Investigation of tenuous plasma environment using Active Spacecraft Potential Control (ASPOC) on Magnetospheric Multiscale (MMS) Mission

NASA Astrophysics Data System (ADS)

Nakamura, Rumi; Jeszenszky, Harald; Torkar, Klaus; Andriopoulou, Maria; Fremuth, Gerhard; Taijmar, Martin; Scharlemann, Carsten; Svenes, Knut; Escoubet, Philippe; Prattes, Gustav; Laky, Gunter; Giner, Franz; Hoelzl, Bernhard

2015-04-01

The NASA's Magnetospheric Multiscale (MMS) Mission is planned to be launched on March 12, 2015. The scientific objectives of the MMS mission are to explore and understand the fundamental plasma physics processes of magnetic reconnection, particle acceleration and turbulence in the Earth's magnetosphere. The region of scientific interest of MMS is in a tenuous plasma environment where the positive spacecraft potential reaches an equilibrium at several tens of Volts. An Active Spacecraft Potential Control (ASPOC) instrument neutralizes the spacecraft potential by releasing positive charge produced by indium ion emitters. ASPOC thereby reduces the potential in order to improve the electric field and low-energy particle measurement. The method has been successfully applied on other spacecraft such as Cluster and Double Star. Two ASPOC units are present on each of the MMS spacecraft. Each unit contains four ion emitters, whereby one emitter per instrument is operated at a time. ASPOC for MMS includes new developments in the design of the emitters and the electronics enabling lower spacecraft potentials, higher reliability, and a more uniform potential structure in the spacecraft's sheath compared to previous missions. Model calculations confirm the findings from previous applications that the plasma measurements will not be affected by the beam's space charge. A perfectly stable spacecraft potential precludes the utilization of the spacecraft as a plasma probe, which is a conventional technique used to estimate ambient plasma density from the spacecraft potential. The small residual variations of the potential controlled by ASPOC, however, still allow to determine ambient plasma density by comparing two closely separated spacecraft and thereby reconstructing the uncontrolled potential variation from the controlled potential. Regular intercalibration of controlled and uncontrolled potentials is expected to increase the reliability of this new method.

Whole genome sequencing in the prevention and control of Staphylococcus aureus infection.

PubMed

Price, J R; Didelot, X; Crook, D W; Llewelyn, M J; Paul, J

2013-01-01

Staphylococcus aureus remains a leading cause of hospital-acquired infection but weaknesses inherent in currently available typing methods impede effective infection prevention and control. The high resolution offered by whole genome sequencing has the potential to revolutionise our understanding and management of S. aureus infection. To outline the practicalities of whole genome sequencing and discuss how it might shape future infection control practice. We review conventional typing methods and compare these with the potential offered by whole genome sequencing. In contrast with conventional methods, whole genome sequencing discriminates down to single nucleotide differences and allows accurate characterisation of transmission events and outbreaks and additionally provides information about the genetic basis of phenotypic characteristics, including antibiotic susceptibility and virulence. However, translating its potential into routine practice will depend on affordability, acceptable turnaround times and on creating a reliable standardised bioinformatic infrastructure. Whole genome sequencing has the potential to provide a universal test that facilitates outbreak investigation, enables the detection of emerging strains and predicts their clinical importance. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Visual evoked potentials of mildly mentally retarded and control children.

PubMed

Gasser, T; Pietz, J; Schellberg, D; Köhler, W

1988-10-01

Visual evoked potentials (VEPs) were recorded from 25 10- to 13-year-old mildly mentally retarded children and compared with those from 31 control children of the same age-range. Correlations of VEPs with age were weak, but a relationship between VEPs and IQ was demonstrated for the control group. The retarded group had significantly longer latencies and higher amplitude peaks than the control group, with the differences occurring primarily over non-specific cortex and for secondary components. Analysis also showed that the retarded group were neurophysiologically heterogeneous. Since the same children had been analyzed earlier by quantitative EEG methods, comparisons are made with respect to these two methods of investigating brain function.

Chemical Ecology of the Colorado Potato Beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), and Potential for Alternative Control Methods

PubMed Central

Sablon, Ludovic; Dickens, Joseph C.; Haubruge, Éric; Verheggen, François J.

2012-01-01

The Colorado potato beetle (CPB) has been a major insect pest to potato farming for over 150 years and various control methods have been established to reduce its impact on potato fields. Crop rotation and pesticide use are currently the most widely used approaches, although alternative methods are being developed. Here we review the role of various volatile and nonvolatile chemicals involved in behavior changes of CPB that may have potential for their control. First, we describe all volatile and nonvolatile chemicals involved in host plant localization and acceptance by CPB beetles, including glycoalcaloids and host plant volatiles used as kairomones. In the second section, we present the chemical signals used by CPB in intraspecific communication, including sex and aggregation pheromones. Some of these chemicals are used by natural enemies of CPBs to locate their prey and are presented in the third section. The last section of this review is devoted a discussion of the potential of some natural chemicals in biological control of CPB and to approaches that already reached efficient field applications. PMID:26466794

Sterility method of pest control and its potential role in an integrated sea lamprey (Petromyzon marinus) control program

USGS Publications Warehouse

Hanson, Lee H.; Manion, Patrick J.

1980-01-01

The sterility method of pest control could be an effective tool in the sea lamprey (Petromyzon marinus) control program in the Great Lakes. Some of the requirements for its successful application have been met. A field study demonstrated that the release of male sea lampreys, sterilized by the injection of 100 mg/kg of P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide (bisazir), will reduce the number of viable larvae produced. The actual reduction in reproductive success that occurred was directly related to the ratio of sterile to normal males in the population. The technique can be used in many ways in an integrated control program and has considerable potential for the more effective control of the sea lamprey. Eradication is a distinct possibility.Key words: sea lamprey, Petromyzon marinus; pest control, fish control, sterile-male technique, sterilization, chemosterilants, bisazir, Great Lakes

Foam property tests to evaluate the potential for longwall shield dust control.

PubMed

Reed, W R; Beck, T W; Zheng, Y; Klima, S; Driscoll, J

2018-01-01

Tests were conducted to determine properties of four foam agents for their potential use in longwall mining dust control. Foam has been tried in underground mining in the past for dust control and is currently being reconsidered for use in underground coal longwall operations in order to help those operations comply with the Mine Safety and Health Administration's lower coal mine respirable dust standard of 1.5 mg/m 3 . Foams were generated using two different methods. One method used compressed air and water pressure to generate foam, while the other method used low-pressure air generated by a blower and water pressure using a foam generator developed by the U.S. National Institute for Occupational Safety and Health. Foam property tests, consisting of a foam expansion ratio test and a water drainage test, were conducted to classify foams. Compressed-air-generated foams tended to have low expansion ratios, from 10 to 19, with high water drainage. Blower-air-generated foams had higher foam expansion ratios, from 30 to 60, with lower water drainage. Foams produced within these ranges of expansion ratios are stable and potentially suitable for dust control. The test results eliminated two foam agents for future testing because they had poor expansion ratios. The remaining two foam agents seem to have properties adequate for dust control. These material property tests can be used to classify foams for their potential use in longwall mining dust control.

Foam property tests to evaluate the potential for longwall shield dust control

PubMed Central

Reed, W.R.; Beck, T.W.; Zheng, Y.; Klima, S.; Driscoll, J.

2018-01-01

Tests were conducted to determine properties of four foam agents for their potential use in longwall mining dust control. Foam has been tried in underground mining in the past for dust control and is currently being reconsidered for use in underground coal longwall operations in order to help those operations comply with the Mine Safety and Health Administration’s lower coal mine respirable dust standard of 1.5 mg/m3. Foams were generated using two different methods. One method used compressed air and water pressure to generate foam, while the other method used low-pressure air generated by a blower and water pressure using a foam generator developed by the U.S. National Institute for Occupational Safety and Health. Foam property tests, consisting of a foam expansion ratio test and a water drainage test, were conducted to classify foams. Compressed-air-generated foams tended to have low expansion ratios, from 10 to 19, with high water drainage. Blower-air-generated foams had higher foam expansion ratios, from 30 to 60, with lower water drainage. Foams produced within these ranges of expansion ratios are stable and potentially suitable for dust control. The test results eliminated two foam agents for future testing because they had poor expansion ratios. The remaining two foam agents seem to have properties adequate for dust control. These material property tests can be used to classify foams for their potential use in longwall mining dust control. PMID:29416179

Field-based random sampling without a sampling frame: control selection for a case-control study in rural Africa.

PubMed

Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E

2001-01-01

Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.

Hydrologic modeling to screen potential environmental management methods for malaria vector control in Niger

NASA Astrophysics Data System (ADS)

Gianotti, Rebecca L.; Bomblies, Arne; Eltahir, Elfatih A. B.

2009-08-01

This paper describes the first use of Hydrology-Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector control in the Sahelian village of Banizoumbou, Niger. The investigation showed that leveling of topographic depressions where temporary breeding habitats form during the rainy season, by altering pool basin microtopography, could reduce the pool persistence time to less than the time needed for establishment of mosquito breeding, approximately 7 days. Undertaking soil surface plowing can also reduce pool persistence time by increasing the infiltration rate through an existing pool basin. Reduction of the pool persistence time to less than the rainfall interstorm period increases the frequency of pool drying events, removing habitat for subadult mosquitoes. Both management approaches could potentially be considered within a given context. This investigation demonstrates that management methods that modify the hydrologic environment have significant potential to contribute to malaria vector control in water-limited, Sahelian Africa.

Control of chemical dynamics by lasers: theoretical considerations.

PubMed

Kondorskiy, Alexey; Nanbu, Shinkoh; Teranishi, Yoshiaki; Nakamura, Hiroki

2010-06-03

Theoretical ideas are proposed for laser control of chemical dynamics. There are the following three elementary processes in chemical dynamics: (i) motion of the wave packet on a single adiabatic potential energy surface, (ii) excitation/de-excitation or pump/dump of wave packet, and (iii) nonadiabatic transitions at conical intersections of potential energy surfaces. A variety of chemical dynamics can be controlled, if we can control these three elementary processes as we desire. For (i) we have formulated the semiclassical guided optimal control theory, which can be applied to multidimensional real systems. The quadratic or periodic frequency chirping method can achieve process (ii) with high efficiency close to 100%. Concerning process (iii) mentioned above, the directed momentum method, in which a predetermined momentum vector is given to the initial wave packet, makes it possible to enhance the desired transitions at conical intersections. In addition to these three processes, the intriguing phenomenon of complete reflection in the nonadiabatic-tunneling-type of potential curve crossing can also be used to control a certain class of chemical dynamics. The basic ideas and theoretical formulations are provided for the above-mentioned processes. To demonstrate the effectiveness of these controlling methods, numerical examples are shown by taking the following processes: (a) vibrational photoisomerization of HCN, (b) selective and complete excitation of the fine structure levels of K and Cs atoms, (c) photoconversion of cyclohexadiene to hexatriene, and (d) photodissociation of OHCl to O + HCl.

Lattice hydrodynamic model based traffic control: A transportation cyber-physical system approach

NASA Astrophysics Data System (ADS)

Liu, Hui; Sun, Dihua; Liu, Weining

2016-11-01

Lattice hydrodynamic model is a typical continuum traffic flow model, which describes the jamming transition of traffic flow properly. Previous studies in lattice hydrodynamic model have shown that the use of control method has the potential to improve traffic conditions. In this paper, a new control method is applied in lattice hydrodynamic model from a transportation cyber-physical system approach, in which only one lattice site needs to be controlled in this control scheme. The simulation verifies the feasibility and validity of this method, which can ensure the efficient and smooth operation of the traffic flow.

Reducing Stator Current Harmonics for a Doubly-Fed Induction Generator Connected to a Distorted Grid

DTIC Science & Technology

2013-09-01

electric grid voltage harmonics, which is a potential obstacle for implementing stable wind -energy systems. Two existing rotor voltage controllers...electric grid voltage harmonics, which is a potential obstacle for implementing stable wind -energy systems. Two existing rotor voltage controllers...speed of the DFIG can be adjusted to optimize turbine efficiency for given wind conditions. A common method for controlling the operating speed is

Electrode Reactions Coupled with Chemical Reactions of Oxygen, Water and Acetaldehyde in an Ionic Liquid: New Approaches for Sensing Volatile Organic Compounds.

PubMed

Chi, Xiaowei; Tang, Yongan; Zeng, Xiangqun

2016-10-20

Water and oxygen are ubiquitous present in ambient conditions. This work studies the unique oxygen, trace water and a volatile organic compound (VOC) acetaldehyde redox chemistry in a hydrophobic and aprotic ionic liquid (IL), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Bmpy] [NTf 2 ]) by cyclic voltammetry and potential step methods. One electron oxygen reduction leads to superoxide radical formation in the IL. Trace water in the IL acts as a protic species that reacts with the superoxide radical. Acetaldehyde is a stronger protic species than water for reacting with the superoxide radical. The presence of trace water in the IL was also demonstrated to facilitate the electro-oxidation of acetaldehyde, with similar mechanism to that in the aqueous solutions. A multiple-step coupling reaction mechanism between water, superoxide radical and acetaldehyde has been described. The unique characteristics of redox chemistry of acetaldehyde in [Bmpy][NTf 2 ] in the presence of oxygen and trace water can be controlled by electrochemical potentials. By controlling the electrode potential windows, several methods including cyclic voltammetry, potential step methods (single-potential, double-potential and triple-potential step methods) were established for the quantification of acetaldehyde. Instead of treating water and oxygen as frustrating interferents to ILs, we found that oxygen and trace water chemistry in [Bmpy][NTf 2 ] can be utilized to develop innovative electrochemical methods for electroanalysis of acetaldehyde.

Electrode Reactions Coupled with Chemical Reactions of Oxygen, Water and Acetaldehyde in an Ionic Liquid: New Approaches for Sensing Volatile Organic Compounds

PubMed Central

Chi, Xiaowei; Tang, Yongan; Zeng, Xiangqun

2017-01-01

Water and oxygen are ubiquitous present in ambient conditions. This work studies the unique oxygen, trace water and a volatile organic compound (VOC) acetaldehyde redox chemistry in a hydrophobic and aprotic ionic liquid (IL), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Bmpy] [NTf2]) by cyclic voltammetry and potential step methods. One electron oxygen reduction leads to superoxide radical formation in the IL. Trace water in the IL acts as a protic species that reacts with the superoxide radical. Acetaldehyde is a stronger protic species than water for reacting with the superoxide radical. The presence of trace water in the IL was also demonstrated to facilitate the electro-oxidation of acetaldehyde, with similar mechanism to that in the aqueous solutions. A multiple-step coupling reaction mechanism between water, superoxide radical and acetaldehyde has been described. The unique characteristics of redox chemistry of acetaldehyde in [Bmpy][NTf2] in the presence of oxygen and trace water can be controlled by electrochemical potentials. By controlling the electrode potential windows, several methods including cyclic voltammetry, potential step methods (single-potential, double-potential and triple-potential step methods) were established for the quantification of acetaldehyde. Instead of treating water and oxygen as frustrating interferents to ILs, we found that oxygen and trace water chemistry in [Bmpy][NTf2] can be utilized to develop innovative electrochemical methods for electroanalysis of acetaldehyde. PMID:29142331

Evaluating efficiency and statistical power of self-controlled case series and self-controlled risk interval designs in vaccine safety.

PubMed

Li, Rongxia; Stewart, Brock; Weintraub, Eric

2016-01-01

The self-controlled case series (SCCS) and self-controlled risk interval (SCRI) designs have recently become widely used in the field of post-licensure vaccine safety monitoring to detect potential elevated risks of adverse events following vaccinations. The SCRI design can be viewed as a subset of the SCCS method in that a reduced comparison time window is used for the analysis. Compared to the SCCS method, the SCRI design has less statistical power due to fewer events occurring in the shorter control interval. In this study, we derived the asymptotic relative efficiency (ARE) between these two methods to quantify this loss in power in the SCRI design. The equation is formulated as [Formula: see text] (a: control window-length ratio between SCRI and SCCS designs; b: ratio of risk window length and control window length in the SCCS design; and [Formula: see text]: relative risk of exposed window to control window). According to this equation, the relative efficiency declines as the ratio of control-period length between SCRI and SCCS methods decreases, or with an increase in the relative risk [Formula: see text]. We provide an example utilizing data from the Vaccine Safety Datalink (VSD) to study the potential elevated risk of febrile seizure following seasonal influenza vaccine in the 2010-2011 season.

An in vitro screening method to evaluate chemicals as potential chemotherapeutants to control Aeromonas hydrophila infection in channel catfish

USDA-ARS?s Scientific Manuscript database

Using catfish gill cells G1B and four chemicals (hydrogen peroxide, sodium chloride, potassium permanganate, and D-mannose), the feasibility of using an in vitro screening method to identify potential effective chemotherapeutants was evaluated in this study. In vitro screening results revealed that,...

Fracture control methods for space vehicles. Volume 1: Fracture control design methods. [for space shuttle configuration planning

NASA Technical Reports Server (NTRS)

Liu, A. F.

1974-01-01

A systematic approach for applying methods for fracture control in the structural components of space vehicles consists of four major steps. The first step is to define the primary load-carrying structural elements and the type of load, environment, and design stress levels acting upon them. The second step is to identify the potential fracture-critical parts by means of a selection logic flow diagram. The third step is to evaluate the safe-life and fail-safe capabilities of the specified part. The last step in the sequence is to apply the control procedures that will prevent damage to the fracture-critical parts. The fracture control methods discussed include fatigue design and analysis methods, methods for preventing crack-like defects, fracture mechanics analysis methods, and nondestructive evaluation methods. An example problem is presented for evaluation of the safe-crack-growth capability of the space shuttle crew compartment skin structure.

Adaptive Engine Technologies for Aviation CO2 Emissions Reduction

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Haller, William J.; Tong, Michael T.

2006-01-01

Adaptive turbine engine technologies are assessed for their potential to reduce carbon dioxide emissions from commercial air transports.Technologies including inlet, fan, and compressor flow control, compressor stall control, blade clearance control, combustion control, active bearings and enabling technologies such as active materials and wireless sensors are discussed. The method of systems assessment is described, including strengths and weaknesses of the approach. Performance benefit estimates are presented for each technology, with a summary of potential emissions reduction possible from the development of new, adaptively controlled engine components.

Evaluation of pH monitoring as a method of processor control.

PubMed

Stears, J G; Gray, J E; Winkler, N T

1979-01-01

Sensitometry and pH values of the developer solution were compared in controlled over-replenishment, developer depletion, fixer contamination experiments, and on a daily quality control basis. The purpose of these comparisons was to evaluate the potential of pH monitoring as a method of processor control, or a supplement to sensitometry as a method of quality control. Reasonable correlation was found between pH values and film density in two of the three experiments but little or no correlation was found in the third experiment and on a day-to-day basis. The conclusion drawn from these comparisons is that pH monitoring has several limitations which render it unsuitable as a method of daily processor quality control as either a primary or supplementary technique. Sensitometry takes into account all the variables encountered in film processing and is the clear method of choice for processor quality control.

Study on a magnetic spiral-type wireless capsule endoscope controlled by rotational external permanent magnet

NASA Astrophysics Data System (ADS)

Ye, Bo; Zhang, Wei; Sun, Zhen-jun; Guo, Lin; Deng, Chao; Chen, Ya-qi; Zhang, Hong-hai; Liu, Sheng

2015-12-01

In this paper, the authors propose rotating an external permanent magnet (EPM) to manipulate the synchronous rotation of a magnetic spiral-type wireless capsule endoscope (WCE), and the synchronous rotation of the WCE is converted to its translational motion in intestinal tract. In order to preliminarily verify the feasibility of this method, a handheld actuator (HA) controlled by micro controller unit, a magnetic spiral-type WCE and a bracket were fabricated, theoretical analysis and simulations about the control distance of this method were performed, and in ex-vivo tests were examined in porcine small intestine to verify the control distance and control performances of this method. It was demonstrated that this method showed good performances in controlling the translational motion of the magnetic spiral-type WCE, and this method has great potential to be used in clinical application.

Size matters: insights from an allometric approach to evaluate control methods for invasive Australian Rhinella marina.

PubMed

Beaty, Lynne E; Salice, Christopher J

2013-10-01

Invasive species are costly and difficult to control. In order to gain a mechanistic understanding of potential control measures, individual-based models uniquely parameterized to reflect the salient life-history characteristics of invasive species are useful. Using invasive Australian Rhinella marina as a case study, we constructed a cohort- and individual-based population simulation that incorporates growth and body size of terrestrial stages. We used this allometric approach to examine the efficacy of nontraditional control methods (i.e., tadpole alarm chemicals and native meat ants) that may have indirect effects on population dynamics mediated by effects on body size. We compared population estimates resulting from these control methods with traditional hand removal. We also conducted a sensitivity analysis to investigate the effect that model parameters, specifically those associated with growth and body size, had on adult population estimates. Incremental increases in hand removal of adults and juveniles caused nonlinear decreases in adult population estimates, suggesting less return with increased investment in hand-removal efforts. Applying tadpole alarm chemicals or meat ants decreased adult population estimates on the same level as removing 15-25% of adults and juveniles by hand. The combined application of tadpole alarm chemicals and meat ants resulted in approximately 80% decrease in adult abundance, the largest of any applied control method. In further support of the nontraditional control methods, which greatly affected the metamorph stage, our model was most sensitive to changes in metamorph survival, juvenile survival, metamorph growth rate, and adult survival. Our results highlight the use and insights that can be gained from individual-based models that incorporate growth and body size and the potential success that nontraditional control methods could have in controlling established, invasive Rhinella marina populations.

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

PubMed Central

Dickey, Michael D.

2016-01-01

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension. Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries. Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude (~500 mN/m to near zero). Furthermore, this method requires only a very modest potential (< 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests. PMID:26863045

Teaching Applied Chemistry in a Pollution Control Context.

ERIC Educational Resources Information Center

Sell, Nancy J.

1982-01-01

Discusses rationale behind and content of a course (Industrial Pollution Control Techniques) combining knowledge from fields of industrial chemistry and chemical engineering and utilizing this knowledge in the context of understanding pollution problems and potential methods of pollution control. (Author/SK)

SUMMARY REPORT CONTROL OF NOX EMISSIONS BY REBURNING

EPA Science Inventory

This report covers NO_x control employing reburning technology: A new, effective method of controlling NO_x emissions from a wide range of stationary combustion sources including large, coal-fired, utility boilers. Although reburning potentially is applicable ...

Aileron controls for wind turbine applications

NASA Technical Reports Server (NTRS)

Miller, D. R.; Putoff, R. L.

1984-01-01

Horizontal axis wind turbines which utilize partial or full variable blade pitch to regulate rotor speed were examined. The weight and costs of these systems indicated a need for alternate methods of rotor control. Aileron control is an alternative which has potential to meet this need. Aileron control rotors were tested on the Mod-O wind turbine to determine their power regulation and shutdown characteristics. Test results for a 20 and 38% chord aileron control rotor are presented. Test is shown that aileron control is a viable method for safety for safely controlling rotor speed, following a loss of general load.

Aileron controls for wind turbine applications

NASA Technical Reports Server (NTRS)

Miller, D. R.; Puthoff, R. L.

1984-01-01

Horizontal axis wind turbines which utilize partial or full variable blade pitch to regulate rotor speed were examined. The weight and costs of these systems indicated a need for alternate methods of rotor control. Aileron control is an alternative which has potential to meet this need. Aileron control rotors were tested on the Mod-O wind turbine to determine their power regulation and shutdown characteristics. Test results for a 20 and 38 percent chord aileron control rotor are presented. Test is shown that aileron control is a viable method for safety for safely controlling rotor speed, following a loss of general load.

Suboptimal artificial potential function sliding mode control for spacecraft rendezvous with obstacle avoidance

NASA Astrophysics Data System (ADS)

Cao, Lu; Qiao, Dong; Xu, Jingwen

2018-02-01

Sub-Optimal Artificial Potential Function Sliding Mode Control (SOAPF-SMC) is proposed for the guidance and control of spacecraft rendezvous considering the obstacles avoidance, which is derived based on the theories of artificial potential function (APF), sliding mode control (SMC) and state dependent riccati equation (SDRE) technique. This new methodology designs a new improved APF to describe the potential field. It can guarantee the value of potential function converge to zero at the desired state. Moreover, the nonlinear terminal sliding mode is introduced to design the sliding mode surface with the potential gradient of APF, which offer a wide variety of controller design alternatives with fast and finite time convergence. Based on the above design, the optimal control theory (SDRE) is also employed to optimal the shape parameter of APF, in order to add some degree of optimality in reducing energy consumption. The new methodology is applied to spacecraft rendezvous with the obstacles avoidance problem, which is simulated to compare with the traditional artificial potential function sliding mode control (APF-SMC) and SDRE to evaluate the energy consumption and control precision. It is demonstrated that the presented method can avoiding dynamical obstacles whilst satisfying the requirements of autonomous rendezvous. In addition, it can save more energy than the traditional APF-SMC and also have better control accuracy than the SDRE.

Control-Volume Analysis Of Thrust-Augmenting Ejectors

NASA Technical Reports Server (NTRS)

Drummond, Colin K.

1990-01-01

New method of analysis of transient flow in thrust-augmenting ejector based on control-volume formulation of governing equations. Considered as potential elements of propulsion subsystems of short-takeoff/vertical-landing airplanes.

Controllable synthesis of rice-shape Alq3 nanoparticles with single crystal structure

NASA Astrophysics Data System (ADS)

Xie, Wanfeng; Fan, Jihui; Song, Hui; Jiang, Feng; Yuan, Huimin; Wei, Zhixian; Ji, Ziwu; Pang, Zhiyong; Han, Shenghao

2016-10-01

We report the controllable growth of rice-shape nanoparticles of Alq3 by an extremely facile self-assembly approach. Possible mechanisms have been proposed to interpret the formation and controlled process of the single crystal nanoparticles. The field-emission performances (turn-on field 7 V μm-1, maximum current density 2.9 mA cm-2) indicate the potential application on miniaturized nano-optoelectronics devices of Alq3-based. This facile method can potentially be used for the controlled synthesis of other functional complexes and organic nanostructures.

Environmental Impacts of Arthropod Biological Control: An Ecological Perspective

USDA-ARS?s Scientific Manuscript database

Arthropod biological control has long been used against insect and mite pests in agriculture production systems, forests, and other natural ecosystems. Depending on the methods of deploying natural enemies and the type of control agents (herbivores, parasitoids, and/or predators), potential environ...

Migratory bird hunter opinions regarding potential management strategies for controlling light goose populations

USGS Publications Warehouse

Dinges, Andrew J.; Webb, Elisabeth B.; Vrtiska, Mark P.; Nilon, Charles H.; Wilhelm Stanis, Sonja A.

2014-01-01

We expanded the Nebraska Light Goose Conservation Order (LGCO) harvest survey (NE, USA) in spring 2012 to assess migratory bird hunter opinions regarding future management strategies for controlling light goose populations. Although hunters strongly agreed that population control of light geese was an important wildlife management issue, they were generally unsupportive of wildlife officials using forms of direct control methods to control light goose populations. Respondents who indicated participation in the 2012 LGCO were also less supportive of any form of direct control compared with migratory bird hunters who did not participate in the LGCO. When presented with alternative methods by wildlife officials for future light goose population control, respondents were most supportive of wildlife agencies selectively shooting light geese on migration and wintering areas and least supportive of wildlife officials using bait with approved chemicals to euthanize light geese. A clear understanding of public perception of various potential direct-control options will likely assist wildlife biologists in making informed decisions on how to proceed with population control of light geese.

Sodium and potassium conductance changes during a membrane action potential.

PubMed

Bezanilla, F; Rojas, E; Taylor, R E

1970-12-01

1. A method for turning a membrane potential control system on and off in less than 10 musec is described. This method was used to record membrane currents in perfused giant axons from Dosidicus gigas and Loligo forbesi after turning on the voltage clamp system at various times during the course of a membrane action potential.2. The membrane current measured just after the capacity charging transient was found to have an almost linear relation to the controlled membrane potential.3. The total membrane conductance taken from these current-voltage curves was found to have a time course during the action potential similar to that found by Cole & Curtis (1939).4. The instantaneous current voltage curves were linear enough to make it possible to obtain a good estimate of the individual sodium and potassium channel conductances, either algebraically or by clamping to the sodium, or potassium, reversal potentials. Good general agreement was obtained with the predictions of the Hodgkin-Huxley equations.5. We consider these results to constitute the first direct experimental demonstration of the conductance changes to sodium and potassium during the course of an action potential.

Computational Fluid Dynamics Simulation Study of Active Power Control in Wind Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul; Aho, Jake; Gebraad, Pieter

2016-08-01

This paper presents an analysis performed on a wind plant's ability to provide active power control services using a high-fidelity computational fluid dynamics-based wind plant simulator. This approach allows examination of the impact on wind turbine wake interactions within a wind plant on performance of the wind plant controller. The paper investigates several control methods for improving performance in waked conditions. One method uses wind plant wake controls, an active field of research in which wind turbine control systems are coordinated to account for their wakes, to improve the overall performance. Results demonstrate the challenge of providing active power controlmore » in waked conditions but also the potential methods for improving this performance.« less

Physically consistent data assimilation method based on feedback control for patient-specific blood flow analysis.

PubMed

Ii, Satoshi; Adib, Mohd Azrul Hisham Mohd; Watanabe, Yoshiyuki; Wada, Shigeo

2018-01-01

This paper presents a novel data assimilation method for patient-specific blood flow analysis based on feedback control theory called the physically consistent feedback control-based data assimilation (PFC-DA) method. In the PFC-DA method, the signal, which is the residual error term of the velocity when comparing the numerical and reference measurement data, is cast as a source term in a Poisson equation for the scalar potential field that induces flow in a closed system. The pressure values at the inlet and outlet boundaries are recursively calculated by this scalar potential field. Hence, the flow field is physically consistent because it is driven by the calculated inlet and outlet pressures, without any artificial body forces. As compared with existing variational approaches, although this PFC-DA method does not guarantee the optimal solution, only one additional Poisson equation for the scalar potential field is required, providing a remarkable improvement for such a small additional computational cost at every iteration. Through numerical examples for 2D and 3D exact flow fields, with both noise-free and noisy reference data as well as a blood flow analysis on a cerebral aneurysm using actual patient data, the robustness and accuracy of this approach is shown. Moreover, the feasibility of a patient-specific practical blood flow analysis is demonstrated. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluation of the resistance of a geopolymer-based drug delivery system to tampering.

PubMed

Cai, Bing; Engqvist, Håkan; Bredenberg, Susanne

2014-04-25

Tamper-resistance is an important property of controlled-release formulations of opioid drugs. Tamper-resistant formulations aim to increase the degree of effort required to override the controlled release of the drug molecules from extended-release formulations for the purpose of non-medical use. In this study, the resistance of a geopolymer-based formulation to tampering was evaluated by comparing it with a commercial controlled-release tablet using several methods commonly used by drug abusers. Because of its high compressive strength and resistance to heat, much more effort and time was required to extract the drug from the geopolymer-based formulation. Moreover, in the drug-release test, the geopolymer-based formulation maintained its controlled-release characteristics after milling, while the drug was released immediately from the milled commercial tablets, potentially resulting in dose dumping. Although the tampering methods used in this study does not cover all methods that abuser could access, the results obtained by the described methods showed that the geopolymer matrix increased the degree of effort required to override the controlled release of the drug, suggesting that the formulation has improved resistance to some common drug-abuse tampering methods. The geopolymer matrix has the potential to make the opioid product less accessible and attractive to non-medical users. Copyright © 2014 Elsevier B.V. All rights reserved.

AI challenges for spacecraft control programs

NASA Technical Reports Server (NTRS)

Lightfoot, Patricia

1986-01-01

The application of AI technology to the spacecraft and experiment command and control systems environment is proposed. The disadvantages of the present methods for analyzing and resolving spacecraft experiment command and control problems are discussed. The potential capabilities and advantages of using AI for the spacecraft and experiment command and control systems are described.

Design, analysis, and interpretation of field quality-control data for water-sampling projects

USGS Publications Warehouse

Mueller, David K.; Schertz, Terry L.; Martin, Jeffrey D.; Sandstrom, Mark W.

2015-01-01

The report provides extensive information about statistical methods used to analyze quality-control data in order to estimate potential bias and variability in environmental data. These methods include construction of confidence intervals on various statistical measures, such as the mean, percentiles and percentages, and standard deviation. The methods are used to compare quality-control results with the larger set of environmental data in order to determine whether the effects of bias and variability might interfere with interpretation of these data. Examples from published reports are presented to illustrate how the methods are applied, how bias and variability are reported, and how the interpretation of environmental data can be qualified based on the quality-control analysis.

Melnikov method approach to control of homoclinic/heteroclinic chaos by weak harmonic excitations.

PubMed

Chacón, Ricardo

2006-09-15

A review on the application of Melnikov's method to control homoclinic and heteroclinic chaos in low-dimensional, non-autonomous and dissipative oscillator systems by weak harmonic excitations is presented, including diverse applications, such as chaotic escape from a potential well, chaotic solitons in Frenkel-Kontorova chains and chaotic-charged particles in the field of an electrostatic wave packet.

Cattle Fever Tick, Rhipicephalus (Boophilus) microplus, (Acari: Ixodidae): potential control on pastures by the application of urea fertilizer

USDA-ARS?s Scientific Manuscript database

The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, spends as much as 80–90% of its life cycle as a larva questing for a host. Standard control methods are limited to on-host applications, leaving a need for methods directed at the pasture infesting stages. Reports from Brazil indic...

Hybrid Method for Power Control Simulation of a Single Fluid Plasma Thruster

NASA Astrophysics Data System (ADS)

Jaisankar, S.; Sheshadri, T. S.

2018-05-01

Propulsive plasma flow through a cylindrical-conical diverging thruster is simulated by a power controlled hybrid method to obtain the basic flow, thermodynamic and electromagnetic variables. Simulation is based on a single fluid model with electromagnetics being described by the equations of potential Poisson, Maxwell and the Ohm's law while the compressible fluid dynamics by the Navier Stokes in cylindrical form. The proposed method solved the electromagnetics and fluid dynamics separately, both to segregate the two prominent scales for an efficient computation and for the delivery of voltage controlled rated power. The magnetic transport is solved for steady state while fluid dynamics is allowed to evolve in time along with an electromagnetic source using schemes based on generalized finite difference discretization. The multistep methodology with power control is employed for simulating fully ionized propulsive flow of argon plasma through the thruster. Numerical solution shows convergence of every part of the solver including grid stability causing the multistep hybrid method to converge for a rated power delivery. Simulation results are reasonably in agreement with the reported physics of plasma flow in the thruster thus indicating the potential utility of this hybrid computational framework, especially when single fluid approximation of plasma is relevant.

Active control of nanolitre droplet contents with convective concentration gradients across permeable walls.

PubMed

Zeitoun, Ramsey I; Goudie, Marcus J; Zwier, Jacob; Mahawilli, David; Burns, Mark A

2011-12-07

Nanolitre droplets in microfluidic devices can be used to perform thousands of independent chemical and biological experiments while minimizing reagents, cost and time. However, the absence of simple and versatile methods capable of controlling the contents of these nanolitre chemical systems limits their scientific potential. To address this, we have developed a method that is simple to fabricate and can continuously control nanolitre chemical systems by integrating a time-resolved convective flow signal across a permeable membrane wall. With this method, we can independently control the volume and concentration of nanolitre-sized drops without ever directly contacting the fluid. Transport occurring in these systems was also analyzed and thoroughly characterized. We achieved volumetric fluid introduction and removal rates ranging from 0.23 to 4.0 pL s(-1). Furthermore, we expanded this method to perform chemical processes. We precipitated silver chloride using a flow signal of sodium chloride and silver nitrate droplets. From there, we were able to separate sodium chloride reactants with a water flow signal, and dissolve silver chloride solids with an ammonia hydroxide flow signal. Finally, we demonstrate the potential to deliver large molecules and perform physical processes like crystallization and particle packing.

Electrical Space Conditioning.

ERIC Educational Resources Information Center

General Electric Co., Cleveland, OH. Large Lamp Dept.

Integrated systems utilizing the heating potential of lighting equipment are discussed in terms of the implications for design and the methods for evaluation and control. General principles cover heat transfer, heat from lamps and luminaires, and control of lighting heat. Suggested systems include--(1) total control systems, (2) bleed-off systems,…

Synthesis of the unmanned aerial vehicle remote control augmentation system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomczyk, Andrzej, E-mail: A.Tomczyk@prz.edu.pl

Medium size Unmanned Aerial Vehicle (UAV) usually flies as an autonomous aircraft including automatic take-off and landing phases. However in the case of the on-board control system failure, the remote steering is using as an emergency procedure. In this reason, remote manual control of unmanned aerial vehicle is used more often during take-of and landing phases. Depends on UAV take-off mass and speed (total energy) the potential crash can be very danger for airplane and environment. So, handling qualities of UAV is important from pilot-operator point of view. In many cases the dynamic properties of remote controlling UAV are notmore » suitable for obtaining the desired properties of the handling qualities. In this case the control augmentation system (CAS) should be applied. Because the potential failure of the on-board control system, the better solution is that the CAS algorithms are placed on the ground station computers. The method of UAV handling qualities shaping in the case of basic control system failure is presented in this paper. The main idea of this method is that UAV reaction on the operator steering signals should be similar - almost the same - as reaction of the 'ideal' remote control aircraft. The model following method was used for controller parameters calculations. The numerical example concerns the medium size MP-02A UAV applied as an aerial observer system.« less

A Review of Transformer Aging and Control Strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gourisetti, Sri Nikhil Gup; Kirkham, Harold; Sivaraman, Deepak

Transformer aging is an important challenge in power system. Distribution transformers themselves are minimally controllable, but smart meters provide excellent, new insights into electrical loads, which insights can be used to understand and mitigate transformer aging. The nature of transformer loads is changing with the integration of distributed energy resources (DERs) and electric vehicles (EVs). This paper first reviews factors that influence the aging of distribution transformers, including root causes of transformer failure. Existing and proposed load control methods are then discussed. A distribution model is introduced to help evaluate potential control methods.

Direct discretization of planar div-curl problems

NASA Technical Reports Server (NTRS)

Nicolaides, R. A.

1989-01-01

A control volume method is proposed for planar div-curl systems. The method is independent of potential and least squares formulations, and works directly with the div-curl system. The novelty of the technique lies in its use of a single local vector field component and two control volumes rather than the other way around. A discrete vector field theory comes quite naturally from this idea and is developed. Error estimates are proved for the method, and other ramifications investigated.

Pilates, Mindfulness and Somatic Education.

PubMed

Caldwell, Karen; Adams, Marianne; Quin, Rebecca; Harrison, Mandy; Greeson, Jeffrey

2013-12-01

The Pilates Method is a form of somatic education with the potential to cultivate mindfulness - a mental quality associated with overall well-being. However, controlled studies are needed to determine whether changes in mindfulness are specific to the Pilates Method or also result from other forms of exercise. This quasi-experimental study compared Pilates Method mat classes and recreational exercise classes on measures of mindfulness and well-being at the beginning, middle and end of a 15 week semester. Total mindfulness scores increased overall for the Pilates Method group but not for the exercise control group, and these increases were directly related to end of semester ratings of self-regulatory self-efficacy, perceived stress and mood. Findings suggest that the Pilates Method specifically enhances mindfulness, and these increases are associated with other measures of wellness. The changes in mindfulness identified in this study support the role of the Pilates Method in the mental well-being of its practitioners and its potential to support dancers' overall well-being.

Pilates, Mindfulness and Somatic Education

PubMed Central

Caldwell, Karen; Quin, Rebecca; Harrison, Mandy; Greeson, Jeffrey

2014-01-01

The Pilates Method is a form of somatic education with the potential to cultivate mindfulness – a mental quality associated with overall well-being. However, controlled studies are needed to determine whether changes in mindfulness are specific to the Pilates Method or also result from other forms of exercise. This quasi-experimental study compared Pilates Method mat classes and recreational exercise classes on measures of mindfulness and well-being at the beginning, middle and end of a 15 week semester. Total mindfulness scores increased overall for the Pilates Method group but not for the exercise control group, and these increases were directly related to end of semester ratings of self-regulatory self-efficacy, perceived stress and mood. Findings suggest that the Pilates Method specifically enhances mindfulness, and these increases are associated with other measures of wellness. The changes in mindfulness identified in this study support the role of the Pilates Method in the mental well-being of its practitioners and its potential to support dancers’ overall well-being. PMID:25328542

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaver, Justin M; Borges, Raymond Charles; Buckner, Mark A

Critical infrastructure Supervisory Control and Data Acquisition (SCADA) systems were designed to operate on closed, proprietary networks where a malicious insider posed the greatest threat potential. The centralization of control and the movement towards open systems and standards has improved the efficiency of industrial control, but has also exposed legacy SCADA systems to security threats that they were not designed to mitigate. This work explores the viability of machine learning methods in detecting the new threat scenarios of command and data injection. Similar to network intrusion detection systems in the cyber security domain, the command and control communications in amore » critical infrastructure setting are monitored, and vetted against examples of benign and malicious command traffic, in order to identify potential attack events. Multiple learning methods are evaluated using a dataset of Remote Terminal Unit communications, which included both normal operations and instances of command and data injection attack scenarios.« less

UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.

PubMed

Chang, Kai; Xia, Yuanqing; Huang, Kaoli

2016-01-01

This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method.

Finite elements and finite differences for transonic flow calculations

NASA Technical Reports Server (NTRS)

Hafez, M. M.; Murman, E. M.; Wellford, L. C.

1978-01-01

The paper reviews the chief finite difference and finite element techniques used for numerical solution of nonlinear mixed elliptic-hyperbolic equations governing transonic flow. The forms of the governing equations for unsteady two-dimensional transonic flow considered are the Euler equation, the full potential equation in both conservative and nonconservative form, the transonic small-disturbance equation in both conservative and nonconservative form, and the hodograph equations for the small-disturbance case and the full-potential case. Finite difference methods considered include time-dependent methods, relaxation methods, semidirect methods, and hybrid methods. Finite element methods include finite element Lax-Wendroff schemes, implicit Galerkin method, mixed variational principles, dual iterative procedures, optimal control methods and least squares.

Demo of Active Resonators on the Active Noise Control Fan

NASA Image and Video Library

1998-10-01

NASA has been involved in several projects to reduce aircraft engine noise. In the 1990s Active Noise Control was investigated as a potential method to reduce aircraft engine noise. A description and demonstration of Active Resonators on the Active Noise Control Fan is shown in this video.

Shape-Controlled Synthesis of Hybrid Nanomaterials via Three-Dimensional Hydrodynamic Focusing

PubMed Central

2015-01-01

Shape-controlled synthesis of nanomaterials through a simple, continuous, and low-cost method is essential to nanomaterials research toward practical applications. Hydrodynamic focusing, with its advantages of simplicity, low-cost, and precise control over reaction conditions, has been used for nanomaterial synthesis. While most studies have focused on improving the uniformity and size control, few have addressed the potential of tuning the shape of the synthesized nanomaterials. Here we demonstrate a facile method to synthesize hybrid materials by three-dimensional hydrodynamic focusing (3D-HF). While keeping the flow rates of the reagents constant and changing only the flow rate of the buffer solution, the molar ratio of two reactants (i.e., tetrathiafulvalene (TTF) and HAuCl4) within the reaction zone varies. The synthesized TTF–Au hybrid materials possess very different and predictable morphologies. The reaction conditions at different buffer flow rates are studied through computational simulation, and the formation mechanisms of different structures are discussed. This simple one-step method to achieve continuous shape-tunable synthesis highlights the potential of 3D-HF in nanomaterials research. PMID:25268035

Shape-controlled synthesis of hybrid nanomaterials via three-dimensional hydrodynamic focusing.

PubMed

Lu, Mengqian; Yang, Shikuan; Ho, Yi-Ping; Grigsby, Christopher L; Leong, Kam W; Huang, Tony Jun

2014-10-28

Shape-controlled synthesis of nanomaterials through a simple, continuous, and low-cost method is essential to nanomaterials research toward practical applications. Hydrodynamic focusing, with its advantages of simplicity, low-cost, and precise control over reaction conditions, has been used for nanomaterial synthesis. While most studies have focused on improving the uniformity and size control, few have addressed the potential of tuning the shape of the synthesized nanomaterials. Here we demonstrate a facile method to synthesize hybrid materials by three-dimensional hydrodynamic focusing (3D-HF). While keeping the flow rates of the reagents constant and changing only the flow rate of the buffer solution, the molar ratio of two reactants (i.e., tetrathiafulvalene (TTF) and HAuCl4) within the reaction zone varies. The synthesized TTF-Au hybrid materials possess very different and predictable morphologies. The reaction conditions at different buffer flow rates are studied through computational simulation, and the formation mechanisms of different structures are discussed. This simple one-step method to achieve continuous shape-tunable synthesis highlights the potential of 3D-HF in nanomaterials research.

Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration.

PubMed

Jäckel, David; Bakkum, Douglas J; Russell, Thomas L; Müller, Jan; Radivojevic, Milos; Frey, Urs; Franke, Felix; Hierlemann, Andreas

2017-04-20

We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron.

Voltage tunability of thermal conductivity in ferroelectric materials

DOEpatents

Ihlefeld, Jon; Hopkins, Patrick Edward

2016-02-09

A method to control thermal energy transport uses mobile coherent interfaces in nanoscale ferroelectric films to scatter phonons. The thermal conductivity can be actively tuned, simply by applying an electrical potential across the ferroelectric material and thereby altering the density of these coherent boundaries to directly impact thermal transport at room temperature and above. The invention eliminates the necessity of using moving components or poor efficiency methods to control heat transfer, enabling a means of thermal energy control at the micro- and nano-scales.

A voltage-controlled capacitive discharge method for electrical activation of peripheral nerves.

PubMed

Rosellini, Will M; Yoo, Paul B; Engineer, Navzer; Armstrong, Scott; Weiner, Richard L; Burress, Chester; Cauller, Larry

2011-01-01

A voltage-controlled capacitive discharge (VCCD) method was investigated as an alternative to rectangular stimulus pulses currently used in peripheral nerve stimulation therapies.  In two anesthetized Gottingen mini pigs, the threshold (total charge per phase) for evoking a compound nerve action potential (CNAP) was compared between constant current (CC) and VCCD methods. Electrical pulses were applied to the tibial and posterior cutaneous femoralis nerves using standard and modified versions of the Medtronic 3778 Octad.  In contrast to CC stimulation, the combined application of VCCD pulses with a modified Octad resulted in a marked decrease (-73 ± 7.4%) in the stimulation threshold for evoking a CNAP. This was consistent for different myelinated fiber types and locations of stimulation.  The VCCD method provides a highly charge-efficient means of activating myelinated fibers that could potentially be used within a wireless peripheral nerve stimulator system. © 2011 International Neuromodulation Society.

Control of operating parameters of laser ceilometers with the application of fiber optic delay line imitation

NASA Astrophysics Data System (ADS)

Kim, A. A.; Klochkov, D. V.; Konyaev, M. A.; Mihaylenko, A. S.

2017-11-01

The article considers the problem of control and verification of the laser ceilometers basic performance parameters and describes an alternative method based on the use of multi-length fiber optic delay line, simulating atmospheric track. The results of the described experiment demonstrate the great potential of this method for inspection and verification procedures of laser ceilometers.

Dynamic control of supplemental lighting for greenhouse

NASA Astrophysics Data System (ADS)

Wang, Yuanxv; Wei, Ruihua; Xu, Lihong

2018-04-01

The development of light-emitting diodes (LED) technology to a large extent reduce the energy consumption of greenhouse, however, the light control methods to realize the energy saving still have great potential. The aim of this paper is to develop a more efficient control method of dynamic control of the LED top-lighting (TL) intensity and the LED inter-lighting (IL) intensity for the greatest economic benefits. A dynamic lighting control algorithm (DLC) based on model is proposed, which defines the economic benefit performance criterion of the supplemental lighting control. The optimal light intensity of TL and IL is calculated in real time according to the algorithm. The simulation shows that economic benefit can be increased by up to 107.35% compared to TL on-off control. It is concluded that DLC is a feasible supplemental light control method, especially under low natural light conditions.

Using Hydrologic Modeling to Screen Potential Environmental Management Methods for Malaria Vector Control in Niger

NASA Astrophysics Data System (ADS)

Gianotti, R. L.; Bomblies, A.; Eltahir, E. A.

2008-12-01

This study describes the use of HYDREMATS, a physically-based distributed hydrology model, to investigate environmental management methods for malaria vector control in the Sahelian village of Banizoumbou, Niger. The model operates at fine spatial and temporal scales to enable explicit simulation of individual pool dynamics and isolation of mosquito breeding habitats. The results showed that leveling of topographic depressions where temporary breeding habitats form during the rainy season could reduce the persistence time of a pool to less than the time needed for establishment of mosquito breeding, approximately 7 days. Increasing the surface soil permeability by ploughing could also reduce the persistence time of a pool but this technique was not as effective as leveling. Therefore it is considered that leveling should be the preferred of the two options where possible. This investigation demonstrates that management methods that modify the hydrologic environment have significant potential to contribute to malaria vector control and human health improvement in Sahelian Africa.

Sodium and potassium conductance changes during a membrane action potential

PubMed Central

Bezanilla, Francisco; Rojas, Eduardo; Taylor, Robert E.

1970-01-01

1. A method for turning a membrane potential control system on and off in less than 10 μsec is described. This method was used to record membrane currents in perfused giant axons from Dosidicus gigas and Loligo forbesi after turning on the voltage clamp system at various times during the course of a membrane action potential. 2. The membrane current measured just after the capacity charging transient was found to have an almost linear relation to the controlled membrane potential. 3. The total membrane conductance taken from these current—voltage curves was found to have a time course during the action potential similar to that found by Cole & Curtis (1939). 4. The instantaneous current voltage curves were linear enough to make it possible to obtain a good estimate of the individual sodium and potassium channel conductances, either algebraically or by clamping to the sodium, or potassium, reversal potentials. Good general agreement was obtained with the predictions of the Hodgkin—Huxley equations. 5. We consider these results to constitute the first direct experimental demonstration of the conductance changes to sodium and potassium during the course of an action potential. PMID:5505231

Distributed systems status and control

NASA Technical Reports Server (NTRS)

Kreidler, David; Vickers, David

1990-01-01

Concepts are investigated for an automated status and control system for a distributed processing environment. System characteristics, data requirements for health assessment, data acquisition methods, system diagnosis methods and control methods were investigated in an attempt to determine the high-level requirements for a system which can be used to assess the health of a distributed processing system and implement control procedures to maintain an accepted level of health for the system. A potential concept for automated status and control includes the use of expert system techniques to assess the health of the system, detect and diagnose faults, and initiate or recommend actions to correct the faults. Therefore, this research included the investigation of methods by which expert systems were developed for real-time environments and distributed systems. The focus is on the features required by real-time expert systems and the tools available to develop real-time expert systems.

Identification of control targets in Boolean molecular network models via computational algebra.

PubMed

Murrugarra, David; Veliz-Cuba, Alan; Aguilar, Boris; Laubenbacher, Reinhard

2016-09-23

Many problems in biomedicine and other areas of the life sciences can be characterized as control problems, with the goal of finding strategies to change a disease or otherwise undesirable state of a biological system into another, more desirable, state through an intervention, such as a drug or other therapeutic treatment. The identification of such strategies is typically based on a mathematical model of the process to be altered through targeted control inputs. This paper focuses on processes at the molecular level that determine the state of an individual cell, involving signaling or gene regulation. The mathematical model type considered is that of Boolean networks. The potential control targets can be represented by a set of nodes and edges that can be manipulated to produce a desired effect on the system. This paper presents a method for the identification of potential intervention targets in Boolean molecular network models using algebraic techniques. The approach exploits an algebraic representation of Boolean networks to encode the control candidates in the network wiring diagram as the solutions of a system of polynomials equations, and then uses computational algebra techniques to find such controllers. The control methods in this paper are validated through the identification of combinatorial interventions in the signaling pathways of previously reported control targets in two well studied systems, a p53-mdm2 network and a blood T cell lymphocyte granular leukemia survival signaling network. Supplementary data is available online and our code in Macaulay2 and Matlab are available via http://www.ms.uky.edu/~dmu228/ControlAlg . This paper presents a novel method for the identification of intervention targets in Boolean network models. The results in this paper show that the proposed methods are useful and efficient for moderately large networks.

REVIEWS OF TOPICAL PROBLEMS: Application of cybernetic methods in physics

NASA Astrophysics Data System (ADS)

Fradkov, Aleksandr L.

2005-02-01

Basic aspects of the subject and methodology for a new and rapidly developing area of research that has emerged at the intersection of physics and control theory (cybernetics) and emphasizes the application of cybernetic methods to the study of physical systems are reviewed. Speed-gradient and Hamiltonian solutions for energy control problems in conservative and dissipative systems are presented. Application examples such as the Kapitza pendulum, controlled overcoming of a potential barrier, and controlling coupled oscillators and molecular systems are presented. A speed-gradient approach to modeling the dynamics of physical systems is discussed.

Sodium influxes in internally perfused squid giant axon during voltage clamp.

PubMed

Atwater, I; Bezanilla, F; Rojas, E

1969-05-01

1. An experimental method for measuring ionic influxes during voltage clamp in the giant axon of Dosidicus is described; the technique combines intracellular perfusion with a method for controlling membrane potential.2. Sodium influx determinations were carried out while applying rectangular pulses of membrane depolarization. The ratio ;measured sodium influx/computed ionic flux during the early current' is 0.92 +/- 0.12.3. Plots of measured sodium influx and computed ionic flux during the early current against membrane potential are very similar. There was evidence that the membrane potential at which the sodium influx vanishes is the potential at which the early current reverses.

Guidelines to birth control counselling of the physically handicapped.

PubMed Central

Szasz, G.; Miller, S.; Anderson, L.

1979-01-01

Birth control counselling of well motivated physically handicapped men and women is discussed in a series of suggested steps: (1) preappointment arrangements are made to ensure physical access to the office, and the partner or a helper may be invited to the visit; (2) the patient is encouraged to name the desired birth control method; (3) the patient's fertility is established from the history and the results of physical examination and laboratory tests; (4) methods of birth control are matched to the patient's physical and mental capabilities; (5) potential side effects of the proposed methods are considered in the light of the handicap; (6) a method is finally recommended that may be a trade-off, with ease of use balanced against efficacy, and living with side effects balanced against the risks of pregnancy; and (7) rechecks are necessary to ensure that the patient is using the method with skill and satisfaction. PMID:156579

Can Land Managers Control Japanese Knotweed? Lessons from Control Tests in Belgium

NASA Astrophysics Data System (ADS)

Delbart, Emmanuel; Mahy, Grégory; Weickmans, Bernard; Henriet, François; Crémer, Sébastien; Pieret, Nora; Vanderhoeven, Sonia; Monty, Arnaud

2012-12-01

Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for land managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides with two application methods (spraying and stem injection), as well as mechanical treatments, on knotweed clones throughout southern Belgium. The tested control methods were selected to be potentially usable by managers, e.g., using legally accepted rates for herbicides. Stem volume, height and density reduction were assessed after one or two years, depending on the control method. Labor estimations were made for each control method. No tested control method completely eradicated the clones. Stem injection with glyphosate-based herbicide (3.6 kg ha-1 of acid equivalent glyphosate) caused the most damage, i.e., no sprouting shoots were observed the year following the injection. The following year, though, stunted shoots appeared. Among the mechanical control methods, repeated cuts combined with native tree transplanting most appreciably reduced knotweed development. The most efficient methods we tested could curb knotweed invasion, but are not likely to be effective in eradicating the species. As such, they should be included in a more integrated restoration strategy, together with prevention and public awareness campaigns.

Antifungal properties of essential oils for improvement of indoor air quality: a review.

PubMed

Whiley, Harriet; Gaskin, Sharyn; Schroder, Tiffany; Ross, Kirstin

2018-03-28

Concerns regarding indoor air quality, particularly the presence of fungi and moulds, are increasing. The potential for essential oils to reduce, control or remove fungi, is gaining interest as they are seen as a "natural" alternative to synthetic chemical fungicides. This review examines published research on essential oils as a method of fungal control in indoor environments. It was difficult to compare the relative performances of essential oils due to differences in research methods and reporting languages. In addition, there are limited studies that scale up laboratory results and assess the efficacy of essential oils within building environments. However, generally, there appears to be some evidence to support the essential oils clove oil, tea tree oil, oregano, thyme and lemon as potential antifungal agents. Essential oils from heartwood, marjoram, cinnamon, lemon basil, caraway, bay tree, fir, peppermint, pine, cedar leaf and manuka were identified in at least one study as having antifungal potential. Future studies should focus on comparing the effectiveness of these essential oils against a large number of fungal isolates from indoor environments. Studies will then need to focus on translating these results into realistic application methods, in actual buildings, and assess the potential for long-term antifungal persistence.

Contaminant treatment method

DOEpatents

Shapiro, Andrew Philip; Thornton, Roy Fred; Salvo, Joseph James

2003-01-01

The present invention provides a method for treating contaminated media. The method comprises introducing remediating ions consisting essentially of ferrous ions, and being peroxide-free, in the contaminated media; applying a potential difference across the contaminated media to cause the remediating ions to migrate into contact with contaminants in the contaminated media; chemically degrading contaminants in the contaminated media by contact with the remediating ions; monitoring the contaminated media for degradation products of the contaminants; and controlling the step of applying the potential difference across the contaminated media in response to the step of monitoring.

Transforming high-dimensional potential energy surfaces into sum-of-products form using Monte Carlo methods

NASA Astrophysics Data System (ADS)

Schröder, Markus; Meyer, Hans-Dieter

2017-08-01

We propose a Monte Carlo method, "Monte Carlo Potfit," for transforming high-dimensional potential energy surfaces evaluated on discrete grid points into a sum-of-products form, more precisely into a Tucker form. To this end we use a variational ansatz in which we replace numerically exact integrals with Monte Carlo integrals. This largely reduces the numerical cost by avoiding the evaluation of the potential on all grid points and allows a treatment of surfaces up to 15-18 degrees of freedom. We furthermore show that the error made with this ansatz can be controlled and vanishes in certain limits. We present calculations on the potential of HFCO to demonstrate the features of the algorithm. To demonstrate the power of the method, we transformed a 15D potential of the protonated water dimer (Zundel cation) in a sum-of-products form and calculated the ground and lowest 26 vibrationally excited states of the Zundel cation with the multi-configuration time-dependent Hartree method.

Development and testing of a weed wiper for roadside vegetative control.

DOT National Transportation Integrated Search

2002-10-01

The objective of the project was to investigate the potential of using the weed wiper applicator : as an alternative method to mowing and broadcast spraying for controlling noxious weds, brush and : plant growth along roadways. An existing weed wiper...

Herbicide Effect on Napiergrass (Pennisetum purpureum Schum.) Control

USDA-ARS?s Scientific Manuscript database

The interest in napiergrass as a renewable cellulosic bio-feedstock for energy production raises concerns with potential methods of control for escaped plants and volunteer plants in successive crops. In greenhouse experiments, hexazinone, glyphosate, and imazapic were applied POST, and CO2 assimila...

Delayed P100-Like Latencies in Multiple Sclerosis: A Preliminary Investigation Using Visual Evoked Spread Spectrum Analysis

PubMed Central

Kiiski, Hanni S. M.; Ní Riada, Sinéad; Lalor, Edmund C.; Gonçalves, Nuno R.; Nolan, Hugh; Whelan, Robert; Lonergan, Róisín; Kelly, Siobhán; O'Brien, Marie Claire; Kinsella, Katie; Bramham, Jessica; Burke, Teresa; Ó Donnchadha, Seán; Hutchinson, Michael; Tubridy, Niall; Reilly, Richard B.

2016-01-01

Conduction along the optic nerve is often slowed in multiple sclerosis (MS). This is typically assessed by measuring the latency of the P100 component of the Visual Evoked Potential (VEP) using electroencephalography. The Visual Evoked Spread Spectrum Analysis (VESPA) method, which involves modulating the contrast of a continuous visual stimulus over time, can produce a visually evoked response analogous to the P100 but with a higher signal-to-noise ratio and potentially higher sensitivity to individual differences in comparison to the VEP. The main objective of the study was to conduct a preliminary investigation into the utility of the VESPA method for probing and monitoring visual dysfunction in multiple sclerosis. The latencies and amplitudes of the P100-like VESPA component were compared between healthy controls and multiple sclerosis patients, and multiple sclerosis subgroups. The P100-like VESPA component activations were examined at baseline and over a 3-year period. The study included 43 multiple sclerosis patients (23 relapsing-remitting MS, 20 secondary-progressive MS) and 42 healthy controls who completed the VESPA at baseline. The follow-up sessions were conducted 12 months after baseline with 24 MS patients (15 relapsing-remitting MS, 9 secondary-progressive MS) and 23 controls, and again at 24 months post-baseline with 19 MS patients (13 relapsing-remitting MS, 6 secondary-progressive MS) and 14 controls. The results showed P100-like VESPA latencies to be delayed in multiple sclerosis compared to healthy controls over the 24-month period. Secondary-progressive MS patients had most pronounced delay in P100-like VESPA latency relative to relapsing-remitting MS and controls. There were no longitudinal P100-like VESPA response differences. These findings suggest that the VESPA method is a reproducible electrophysiological method that may have potential utility in the assessment of visual dysfunction in multiple sclerosis. PMID:26726800

Real-time reflectometry measurement validation in H-mode regimes for plasma position control.

PubMed

Santos, J; Guimarais, L; Manso, M

2010-10-01

It has been shown that in H-mode regimes, reflectometry electron density profiles and an estimate for the density at the separatrix can be jointly used to track the separatrix within the precision required for plasma position control on ITER. We present a method to automatically remove, from the position estimation procedure, measurements performed during collapse and recovery phases of edge localized modes (ELMs). Based on the rejection mechanism, the method also produces an estimate confidence value to be fed to the position feedback controller. Preliminary results show that the method improves the real-time experimental separatrix tracking capabilities and has the potential to eliminate the need for an external online source of ELM event signaling during control feedback operation.

Underpotential deposition-mediated layer-by-layer growth of thin films

DOEpatents

Wang, Jia Xu; Adzic, Radoslav R.

2017-06-27

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves electrochemically exchanging a mediating element on a substrate with a noble metal film by alternatingly sweeping potential in forward and reverse directions for a predetermined number of times in an electrochemical cell. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis.

Advanced Guidance and Control Methods for Reusable Launch Vehicles: Test Results

NASA Technical Reports Server (NTRS)

Hanson, John M.; Jones, Robert E.; Krupp, Don R.; Fogle, Frank R. (Technical Monitor)

2002-01-01

There are a number of approaches to advanced guidance and control (AG&C) that have the potential for achieving the goals of significantly increasing reusable launch vehicle (RLV) safety/reliability and reducing the cost. In this paper, we examine some of these methods and compare the results. We briefly introduce the various methods under test, list the test cases used to demonstrate that the desired results are achieved, show an automated test scoring method that greatly reduces the evaluation effort required, and display results of the tests. Results are shown for the algorithms that have entered testing so far.

Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System.

PubMed

Bagny Beilhe, Leïla; Piou, Cyril; Tadu, Zéphirin; Babin, Régis

2018-06-06

The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.

A computerized test system for thermal-mechanical fatigue crack growth

NASA Technical Reports Server (NTRS)

Marchand, N.; Pelloux, R. M.

1986-01-01

A computerized testing system to measure fatigue crack growth under thermal-mechanical fatigue conditions is described. Built around a servohydraulic machine, the system is capable of a push-pull test under stress-controlled or strain-controlled conditions in the temperature range of 25 to 1050 C. Temperature and mechanical strain are independently controlled by the closed-loop system to simulate the complex inservice strain-temperature relationship. A d-c electrical potential method is used to measure crack growth rates. The correction procedure of the potential signal to take into account powerline and RF-induced noises and thermal changes is described. It is shown that the potential drop technique can be used for physical mechanism studies and for modelling crack tip processes.

NEUTRON DENSITY CONTROL IN A NEUTRONIC REACTOR

DOEpatents

Young, G.J.

1959-06-30

The method and means for controlling the neutron density in a nuclear reactor is described. It describes the method and means for flattening the neutron density distribution curve across the reactor by spacing the absorbing control members to varying depths in the central region closer to the center than to the periphery of the active portion of the reactor to provide a smaller neutron reproduction ratio in the region wherein the members are inserted, than in the remainder of the reactor thereby increasing the over-all potential power output.

The Case for Intelligent Propulsion Control for Fast Engine Response

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Frederick, Dean K.; Guo, Ten-Huei

2009-01-01

Damaged aircraft have occasionally had to rely solely on thrust to maneuver as a consequence of losing hydraulic power needed to operate flight control surfaces. The lack of successful landings in these cases inspired research into more effective methods of utilizing propulsion-only control. That research demonstrated that one of the major contributors to the difficulty in landing is the slow response of the engines as compared to using traditional flight control. To address this, research is being conducted into ways of making the engine more responsive under emergency conditions. This can be achieved by relaxing controller limits, adjusting schedules, and/or redesigning the regulators to increase bandwidth. Any of these methods can enable faster response at the potential expense of engine life and increased likelihood of stall. However, an example sensitivity analysis revealed a complex interaction of the limits and the difficulty in predicting the way to achieve the fastest response. The sensitivity analysis was performed on a realistic engine model, and demonstrated that significantly faster engine response can be achieved compared to standard Bill of Material control. However, the example indicates the need for an intelligent approach to controller limit adjustment in order for the potential to be fulfilled.

Salmonella and eggs: from production to plate.

PubMed

Whiley, Harriet; Ross, Kirstin

2015-02-26

Salmonella contamination of eggs and egg shells has been identified as a public health concern worldwide. A recent shift in consumer preferences has impacted on the egg industry, with a push for cage-free egg production methods. There has also been an increased desire from consumers for raw and unprocessed foods, potentially increasing the risk of salmonellosis. In response to these changes, this review explores the current literature regarding Salmonella contamination of eggs during the production processing through to food handling protocols. The contamination of eggs with Salmonella during the production process is a complex issue, influenced by many variables including flock size, flock age, stress, feed, vaccination, and cleaning routines. Currently there is no consensus regarding the impact of caged, barn and free range egg production has on Salmonella contamination of eggs. The literature regarding the management and control strategies post-collection, during storage, transport and food handling is also reviewed. Pasteurisation and irradiation were identified as the only certain methods for controlling Salmonella and are essential for the protection of high risk groups, whereas control of temperature and pH were identified as potential control methods to minimise the risk for foods containing raw eggs; however, further research is required to provide more detailed control protocols and education programs to reduce the risk of salmonellosis from egg consumption.

Salmonella and Eggs: From Production to Plate

PubMed Central

Whiley, Harriet; Ross, Kirstin

2015-01-01

Salmonella contamination of eggs and egg shells has been identified as a public health concern worldwide. A recent shift in consumer preferences has impacted on the egg industry, with a push for cage-free egg production methods. There has also been an increased desire from consumers for raw and unprocessed foods, potentially increasing the risk of salmonellosis. In response to these changes, this review explores the current literature regarding Salmonella contamination of eggs during the production processing through to food handling protocols. The contamination of eggs with Salmonella during the production process is a complex issue, influenced by many variables including flock size, flock age, stress, feed, vaccination, and cleaning routines. Currently there is no consensus regarding the impact of caged, barn and free range egg production has on Salmonella contamination of eggs. The literature regarding the management and control strategies post-collection, during storage, transport and food handling is also reviewed. Pasteurisation and irradiation were identified as the only certain methods for controlling Salmonella and are essential for the protection of high risk groups, whereas control of temperature and pH were identified as potential control methods to minimise the risk for foods containing raw eggs; however, further research is required to provide more detailed control protocols and education programs to reduce the risk of salmonellosis from egg consumption. PMID:25730295

Temporally controlled release of multiple growth factors from a self-assembling peptide hydrogel

NASA Astrophysics Data System (ADS)

Bruggeman, Kiara F.; Rodriguez, Alexandra L.; Parish, Clare L.; Williams, Richard J.; Nisbet, David R.

2016-09-01

Protein growth factors have demonstrated great potential for tissue repair, but their inherent instability and large size prevents meaningful presentation to biologically protected nervous tissue. Here, we create a nanofibrous network from a self-assembling peptide (SAP) hydrogel to carry and stabilize the growth factors. We significantly reduced growth factor degradation to increase their lifespan by over 40 times. To control the temporal release profile we covalently attached polysaccharide chitosan molecules to the growth factor to increase its interactions with the hydrogel nanofibers and achieved a 4 h delay, demonstrating the potential of this method to provide temporally controlled growth factor delivery. We also describe release rate based analysis to examine the growth factor delivery in more detail than standard cumulative release profiles allow and show that the chitosan attachment method provided a more consistent release profile with a 60% reduction in fluctuations. To prove the potential of this system as a complex growth factor delivery platform we demonstrate for the first time temporally distinct release of multiple growth factors from a single tissue specific SAP hydrogel: a significant goal in regenerative medicine.

Networked event-triggered control: an introduction and research trends

NASA Astrophysics Data System (ADS)

Mahmoud, Magdi S.; Sabih, Muhammad

2014-11-01

A physical system can be studied as either continuous time or discrete-time system depending upon the control objectives. Discrete-time control systems can be further classified into two categories based on the sampling: (1) time-triggered control systems and (2) event-triggered control systems. Time-triggered systems sample states and calculate controls at every sampling instant in a periodic fashion, even in cases when states and calculated control do not change much. This indicates unnecessary and useless data transmission and computation efforts of a time-triggered system, thus inefficiency. For networked systems, the transmission of measurement and control signals, thus, cause unnecessary network traffic. Event-triggered systems, on the other hand, have potential to reduce the communication burden in addition to reducing the computation of control signals. This paper provides an up-to-date survey on the event-triggered methods for control systems and highlights the potential research directions.

Applicator Training Manual for: Agricultural Animal Pest Control.

ERIC Educational Resources Information Center

Christensen, Christian M.

This manual discusses pesticide safety and environmental considerations, pesticide toxicity, residue potential, pesticide formulations, and application techniques. In addition, descriptions of, and methods for controlling insects and related pests that attack cattle, sheep and goats, swine, horses and other equines, and poultry are given. These…

Seaweed Bioactive Compounds against Pathogens and Microalgae: Potential Uses on Pharmacology and Harmful Algae Bloom Control.

PubMed

Zerrifi, Soukaina El Amrani; El Khalloufi, Fatima; Oudra, Brahim; Vasconcelos, Vitor

2018-02-09

Cyanobacteria are found globally due to their adaptation to various environments. The occurrence of cyanobacterial blooms is not a new phenomenon. The bloom-forming and toxin-producing species have been a persistent nuisance all over the world over the last decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. To control cyanobacterial blooms, various strategies, including physical, chemical, and biological methods have been proposed. Nevertheless, the use of those strategies is usually not effective. The isolation of natural compounds from many aquatic and terrestrial plants and seaweeds has become an alternative approach for controlling harmful algae in aquatic systems. Seaweeds have received attention from scientists because of their bioactive compounds with antibacterial, antifungal, anti-microalgae, and antioxidant properties. The undesirable effects of cyanobacteria proliferations and potential control methods are here reviewed, focusing on the use of potent bioactive compounds, isolated from seaweeds, against microalgae and cyanobacteria growth.

Seaweed Bioactive Compounds against Pathogens and Microalgae: Potential Uses on Pharmacology and Harmful Algae Bloom Control

PubMed Central

Zerrifi, Soukaina El Amrani; El Khalloufi, Fatima; Oudra, Brahim; Vasconcelos, Vitor

2018-01-01

Cyanobacteria are found globally due to their adaptation to various environments. The occurrence of cyanobacterial blooms is not a new phenomenon. The bloom-forming and toxin-producing species have been a persistent nuisance all over the world over the last decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. To control cyanobacterial blooms, various strategies, including physical, chemical, and biological methods have been proposed. Nevertheless, the use of those strategies is usually not effective. The isolation of natural compounds from many aquatic and terrestrial plants and seaweeds has become an alternative approach for controlling harmful algae in aquatic systems. Seaweeds have received attention from scientists because of their bioactive compounds with antibacterial, antifungal, anti-microalgae, and antioxidant properties. The undesirable effects of cyanobacteria proliferations and potential control methods are here reviewed, focusing on the use of potent bioactive compounds, isolated from seaweeds, against microalgae and cyanobacteria growth. PMID:29425153

Specifying the Probability Characteristics of Funnel Plot Control Limits: An Investigation of Three Approaches

PubMed Central

Manktelow, Bradley N.; Seaton, Sarah E.

2012-01-01

Background Emphasis is increasingly being placed on the monitoring and comparison of clinical outcomes between healthcare providers. Funnel plots have become a standard graphical methodology to identify outliers and comprise plotting an outcome summary statistic from each provider against a specified ‘target’ together with upper and lower control limits. With discrete probability distributions it is not possible to specify the exact probability that an observation from an ‘in-control’ provider will fall outside the control limits. However, general probability characteristics can be set and specified using interpolation methods. Guidelines recommend that providers falling outside such control limits should be investigated, potentially with significant consequences, so it is important that the properties of the limits are understood. Methods Control limits for funnel plots for the Standardised Mortality Ratio (SMR) based on the Poisson distribution were calculated using three proposed interpolation methods and the probability calculated of an ‘in-control’ provider falling outside of the limits. Examples using published data were shown to demonstrate the potential differences in the identification of outliers. Results The first interpolation method ensured that the probability of an observation of an ‘in control’ provider falling outside either limit was always less than a specified nominal probability (p). The second method resulted in such an observation falling outside either limit with a probability that could be either greater or less than p, depending on the expected number of events. The third method led to a probability that was always greater than, or equal to, p. Conclusion The use of different interpolation methods can lead to differences in the identification of outliers. This is particularly important when the expected number of events is small. We recommend that users of these methods be aware of the differences, and specify which interpolation method is to be used prior to any analysis. PMID:23029202

Performance Characterization, Development, and Application of Artificial Potential Function Guidance Methods

DTIC Science & Technology

2014-03-01

to determine if a system is stabilizable with feedback. 12 that asymptotic stability is guaranteed by Lyapunov theory. The advantage of this method are...discretized dynamics are a sufficient representation of the continuous system . Given these assumptions, the optimal control problem for minimum transit time is...tion (APF) guidance performance when applied to systems with limited control au- thority in a dynamic environment and then to use the findings to

Exploiting Task Constraints for Self-Calibrated Brain-Machine Interface Control Using Error-Related Potentials

PubMed Central

Iturrate, Iñaki; Grizou, Jonathan; Omedes, Jason; Oudeyer, Pierre-Yves; Lopes, Manuel; Montesano, Luis

2015-01-01

This paper presents a new approach for self-calibration BCI for reaching tasks using error-related potentials. The proposed method exploits task constraints to simultaneously calibrate the decoder and control the device, by using a robust likelihood function and an ad-hoc planner to cope with the large uncertainty resulting from the unknown task and decoder. The method has been evaluated in closed-loop online experiments with 8 users using a previously proposed BCI protocol for reaching tasks over a grid. The results show that it is possible to have a usable BCI control from the beginning of the experiment without any prior calibration. Furthermore, comparisons with simulations and previous results obtained using standard calibration hint that both the quality of recorded signals and the performance of the system were comparable to those obtained with a standard calibration approach. PMID:26131890

CdS/TiO2 photoanodes via solution ion transfer method for highly efficient solar hydrogen generation

NASA Astrophysics Data System (ADS)

Krishna Karuturi, Siva; Yew, Rowena; Reddy Narangari, Parvathala; Wong-Leung, Jennifer; Li, Li; Vora, Kaushal; Tan, Hark Hoe; Jagadish, Chennupati

2018-03-01

Cadmium sulfide (CdS) is a unique semiconducting material for solar hydrogen generation applications with a tunable, narrow bandgap that straddles water redox potentials. However, its potential towards efficient solar hydrogen generation has not yet been realized due to low photon-to-current conversions, high charge carrier recombination and the lack of controlled preparation methods. In this work, we demonstrate a highly efficient CdS/TiO2 heterostructured photoelectrode using atomic layer deposition and solution ion transfer reactions. Enabled by the well-controlled deposition of CdS nanocrystals on TiO2 inverse opal (TiIO) nanostructures using the proposed method, a saturation photocurrent density of 9.1 mA cm-2 is realized which is the highest ever reported for CdS-based photoelectrodes. We further demonstrate that the passivation of a CdS surface with an ultrathin amorphous layer (˜1.5 nm) of TiO2 improves the charge collection efficiency at low applied potentials paving the way for unassisted solar hydrogen generation.

Website Physical Activity Interventions: Preferences of Potential Users

ERIC Educational Resources Information Center

Ferney, Shannon L.; Marshall, Alison L.

2006-01-01

Information and communication technologies (particularly websites and e-mail) have the potential to deliver health behavior change programs to large numbers of adults at low cost. Controlled trials using these new media to promote physical activity have produced mixed results. User-centered development methods can assist in understanding the…

Developments in Signature Process Control

NASA Astrophysics Data System (ADS)

Keller, L. B.; Dominski, Marty

1993-01-01

Developments in the adaptive process control technique known as Signature Process Control for Advanced Composites (SPCC) are described. This computer control method for autoclave processing of composites was used to develop an optimum cure cycle for AFR 700B polyamide and for an experimental poly-isoimide. An improved process cycle was developed for Avimid N polyamide. The potential for extending the SPCC technique to pre-preg quality control, press modeling, pultrusion and RTM is briefly discussed.

Controlling ionotropic and metabotropic glutamate receptors with light: principles and potential

PubMed Central

Reiner, Andreas; Levitz, Joshua; Isacoff, Ehud Y.

2014-01-01

Light offers unique advantages for studying and manipulating biomolecules and the cellular processes that they control. Optical control of ionotropic and metabotropic glutamate receptors has garnered significant interest, since these receptors are central to signaling at neuronal synapses and only optical approaches provide the spatial and temporal resolution required to directly probe receptor function in cells and tissue. Following the classical method of glutamate photo-uncaging, recently developed methods have added other forms of remote control, including those with high molecular specificity and genetic targeting. These tools open the door to the direct optical control of synaptic transmission and plasticity, as well as the probing of native receptor function in intact neural circuits. PMID:25573450

Novel strategies for controlling Streptococcus pyogenes infection and associated diseases: from potential peptide vaccines to antibody immunotherapy.

PubMed

Pandey, Manisha; Sekuloski, Silvana; Batzloff, Michael R

2009-07-01

Infections caused by group A streptococcus (GAS) represent a public health problem in both developing and developed countries. The current available methods of prevention are either inadequate or ineffective, which is highlighted by the resurgence in invasive GAS infections over the past two decades. The management of GAS and associated diseases requires new and improved approaches. This review discusses various potential approaches in controlling GAS infections, ranging from prophylactic vaccines to antibody immunotherapy.

Subsonic panel method for designing wing surfaces from pressure distribution

NASA Technical Reports Server (NTRS)

Bristow, D. R.; Hawk, J. D.

1983-01-01

An iterative method has been developed for designing wing section contours corresponding to a prescribed subcritical distribution of pressure. The calculations are initialized by using a surface panel method to analyze a baseline wing or wing-fuselage configuration. A first-order expansion to the baseline panel method equations is then used to calculate a matrix containing the partial derivative of potential at each control point with respect to each unknown geometry parameter. In every iteration cycle, the matrix is used both to calculate the geometry perturbation and to analyze the perturbed geometry. The distribution of potential on the perturbed geometry is established by simple linear extrapolation from the baseline solution. The extrapolated potential is converted to pressure by Bernoulli's equation. Not only is the accuracy of the approach good for very large perturbations, but the computing cost of each complete iteration cycle is substantially less than one analysis solution by a conventional panel method.

Sodium influxes in internally perfused squid giant axon during voltage clamp

PubMed Central

Atwater, I.; Bezanilla, F.; Rojas, E.

1969-01-01

1. An experimental method for measuring ionic influxes during voltage clamp in the giant axon of Dosidicus is described; the technique combines intracellular perfusion with a method for controlling membrane potential. 2. Sodium influx determinations were carried out while applying rectangular pulses of membrane depolarization. The ratio `measured sodium influx/computed ionic flux during the early current' is 0·92 ± 0·12. 3. Plots of measured sodium influx and computed ionic flux during the early current against membrane potential are very similar. There was evidence that the membrane potential at which the sodium influx vanishes is the potential at which the early current reverses. PMID:5767887

Development of space-stable thermal control coatings for use on large space vehicles

NASA Technical Reports Server (NTRS)

Gilligan, J. E.; Harada, Y.

1976-01-01

The potential of zinc orthotitanate as a pigment for spacecraft thermal control was demonstrated. The properties and performance of pigments prepared by solid state, coprecipitation, and mixed oxalate methods were compared. Environmental tests and subsequent spectral analysis were given primary emphasis.

Self-regulating control of parasitic loads in a fuel cell power system

NASA Technical Reports Server (NTRS)

Vasquez, Arturo (Inventor)

2011-01-01

A fuel cell power system comprises an internal or self-regulating control of a system or device requiring a parasitic load. The internal or self-regulating control utilizes certain components and an interconnection scheme to produce a desirable, variable voltage potential (i.e., power) to a system or device requiring parasitic load in response to varying operating conditions or requirements of an external load that is connected to a primary fuel cell stack of the system. Other embodiments comprise a method of designing such a self-regulated control scheme and a method of operating such a fuel cell power system.

On controlling networks of limit-cycle oscillators

NASA Astrophysics Data System (ADS)

Skardal, Per Sebastian; Arenas, Alex

2016-09-01

The control of network-coupled nonlinear dynamical systems is an active area of research in the nonlinear science community. Coupled oscillator networks represent a particularly important family of nonlinear systems, with applications ranging from the power grid to cardiac excitation. Here, we study the control of network-coupled limit cycle oscillators, extending the previous work that focused on phase oscillators. Based on stabilizing a target fixed point, our method aims to attain complete frequency synchronization, i.e., consensus, by applying control to as few oscillators as possible. We develop two types of controls. The first type directs oscillators towards larger amplitudes, while the second does not. We present numerical examples of both control types and comment on the potential failures of the method.

Gone viral? Heard the buzz? A guide for public health practitioners and researchers on how Web 2.0 can subvert advertising restrictions and spread health information.

PubMed

Freeman, B; Chapman, S

2008-09-01

Many nations have banned or curtailed advertising of potentially harmful products to protect public health, particularly in the area of chronic disease control. The growth in Internet-based marketing techniques is subverting these advertising regulations. Explosive rises in use of social networking and user-generated content websites is further fuelling product promotion through electronic media. In contrast, there is a very limited body of public health research on these "new media" advertising methods. This paper provides an overview of these advertising methods and details examples relevant to chronic disease control. There is a vast untapped potential for health practitioners and researchers to exploit these same media for health promotion.

Novel approach for the simultaneous detection of DNA from different fish species based on a nuclear target: quantification potential.

PubMed

Prado, Marta; Boix, Ana; von Holst, Christoph

2012-07-01

The development of DNA-based methods for the identification and quantification of fish in food and feed samples is frequently focused on a specific fish species and/or on the detection of mitochondrial DNA of fish origin. However, a quantitative method for the most common fish species used by the food and feed industry is needed for official control purposes, and such a method should rely on the use of a single-copy nuclear DNA target owing to its more stable copy number in different tissues. In this article, we report on the development of a real-time PCR method based on the use of a nuclear gene as a target for the simultaneous detection of fish DNA from different species and on the evaluation of its quantification potential. The method was tested in 22 different fish species, including those most commonly used by the food and feed industry, and in negative control samples, which included 15 animal species and nine feed ingredients. The results show that the method reported here complies with the requirements concerning specificity and with the criteria required for real-time PCR methods with high sensitivity.

Mixed-Potential NO x and NH 3 Sensors Fabricated by Commercial Manufacturing Methods [Mixed-Potential Sensors NO x and NH 3 Fabricated by Commercial Manufacturing Methods

DOE PAGES

Kreller, Cortney R.; Spernjak, Dusan; Li, Wenxia; ...

2014-08-12

Meeting EPA Tier 3 emissions reduction requirements while simultaneously increasing fuel economy to meet new CAFE standards will require optimization of advanced combustion strategies and emissions control technologies. There is an immediate need for suitable exhaust gas sensor technologies to monitor internal combustion engine tailpipe emissions and to control and maintain efficient operation of the engine and exhaust after treatment systems. NH 3, NO x, and HC sensors could enable onboard diagnostics and combustion control in lean-burn engines, analogous to the role of O 2 sensors in stoichiometric burn engines. Commercial manufacturing methods have been used to fabricate self-heated mixed-potentialmore » sensors in a planar automotive configuration. By altering materials composition and operating conditions, we are able to obtain sensitivity/selectivity to each NH 3, NO x and HCs. In addition, these devices exhibit stable performance over months of testing as a result of the stable morphology of the electrode/electrolyte/gas three-phase interface.« less

Patterning nanofibrils through the templated growth of multiple modified amyloid peptides

PubMed Central

Sakai, Hiroki; Watanabe, Ken; Kudoh, Fuki; Kamada, Rui; Chuman, Yoshiro; Sakaguchi, Kazuyasu

2016-01-01

There has been considerable interest in the patterning of functionalized nanowires because of the potential applications of these materials to the construction of nanodevices. A variety of biomolecular building blocks containing amyloid peptides have been used to functionalize nanowires. However, the patterning of self-assembled nanowires can be challenging because of the difficulties associated with controlling the self-assembly of these functionalized building blocks. Herein, we present a versatile approach for the patterning of nanowires based on the combination of templated fibril growth with a versatile functionalization method using our structure-controllable amyloid peptides (SCAPs). Using this approach, we have succeeded in the formation of multi-type nanowires with tandem domain structures in high yields. Given that the mixing-SCAP method can lead to the formation of tandem fibrils, it is noteworthy that our method allowed us to control the initiation of fibril formation from the gold nanoparticles, which were attached to a short fibril as initiation points. This approach could be used to prepare a wide variety of fibril patterns, and therefore holds great potential for the development of novel self-assembled nanodevices. PMID:27559011

Online market research panel members as controls in case-control studies to investigate gastrointestinal disease outbreaks: early experiences and lessons learnt from the UK.

PubMed

Mook, P; McCormick, J; Kanagarajah, S; Adak, G K; Cleary, P; Elson, R; Gobin, M; Hawker, J; Inns, T; Sinclair, C; Trienekens, S C M; Vivancos, R; McCarthy, N D

2018-03-01

Established methods of recruiting population controls for case-control studies to investigate gastrointestinal disease outbreaks can be time consuming, resulting in delays in identifying the source or vehicle of infection. After an initial evaluation of using online market research panel members as controls in a case-control study to investigate a Salmonella outbreak in 2013, this method was applied in four further studies in the UK between 2014 and 2016. We used data from all five studies and interviews with members of each outbreak control team and market research panel provider to review operational issues, evaluate risk of bias in this approach and consider methods to reduce confounding and bias. The investigators of each outbreak reported likely time and cost savings from using market research controls. There were systematic differences between case and control groups in some studies but no evidence that conclusions on the likely source or vehicle of infection were incorrect. Potential selection biases introduced by using this sampling frame and the low response rate are unclear. Methods that might reduce confounding and some bias should be balanced with concerns for overmatching. Further evaluation of this approach using comparisons with traditional methods and population-based exposure survey data is recommended.

Discussion on a Potential DJ Basin Pneumatic Controller ...

EPA Pesticide Factsheets

ORD NRMRL and Region 8 collaborators are conducting emission measurements and method development studies on pneumatic controllers (PCs) in the Uintah Basin, Utah (and potentially in Colorado), in cooperation with Oil and Natural gas (ONG) operators. ONG operations use PCs for production process control and safety functions. PCs emit gas to the atmosphere as they operate and sometimes they malfunction and emit more than they are supposed to. Because of the very large number of PCs in use, these devices contribute significantly to greenhouse gas (GHG) and volatile organic compound (VOC) emissions. There is considerable uncertainty in levels of real-world PC emissions and measurement methods for PCs are somewhat underdeveloped. In collaboration with EPA R8, the State of Colorado, (and industry participants in Step 2), ORD NRMRL is evaluating a potential follow-on research effort to the Uinta Basin Pneumatic Controller (PC) Study. The Uinta PC Study is described in a recent APPCD Research Highlight (attached )with results summarized in “Assessment of Uinta Basin Oil and Natural Gas Well Pad Pneumatic Controller Emissions”, E. Thoma et al., Journal of Environmental Protection, 8, 394-415, (2017). doi: 10.4236/jep.2017.84029; at (http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=75669). This RAP research was funded by an EPA R8 RARE and ACE Task EM 1.2 (next gen. emissions measurements). For both technical and programmatic reasons, we seek to

The potential use of ultrasound to control the trematode bolbophorus confusus by eliminating the ram's horn snail planorbella trivolvis in commercial aquaculture settings

USDA-ARS?s Scientific Manuscript database

One method in the investigation of acoustics to improve aquaculture production is the use of ultrasound to control the trematode, Bolbophorus confuses, in commercial catfish ponds. The trematode population can be controlled by eliminating the host ram’s horn snail, Planorbella trivolvis, which is ty...

The Utility of Case-Control Methods for Health Policy and Planning Analysis: An Illustration from Kinshasa, Zaire.

ERIC Educational Resources Information Center

Mock, Nancy B.; And Others

1993-01-01

The use of case-control methodology as an applied policy/planning research tool in assessing the potential effectiveness of behavioral interventions is studied in connection with diarrhea control in Zaire. Results with 107 matched pairs of children demonstrate the importance of hygiene-related knowledge and the utility of the research approach.…

The biological control of Pomacea canaliculata population by rice-duck mutualism in paddy fields

Treesearch

Kiang Liang; Jia-en Zhang; Li Fang; Benliang Zaho; Mingzhu Luo; Prem Parajuli; Ying Ouyang

2013-01-01

Duck has been used as a non-chemical control method against Pomacea canaliculata Lamarck, but little is known about its principles that underlie the control of snail populations. An indoor experiment was initially used to observe the predation potential of ducks, followed by replicated field trials. In the indoor studies, ducks effectively preyed on...

Control of spiral waves and turbulent states in a cardiac model by travelling-wave perturbations

NASA Astrophysics Data System (ADS)

Wang, Peng-Ye; Xie, Ping; Yin, Hua-Wei

2003-06-01

We propose a travelling-wave perturbation method to control the spatiotemporal dynamics in a cardiac model. It is numerically demonstrated that the method can successfully suppress the wave instability (alternans in action potential duration) in the one-dimensional case and convert spiral waves and turbulent states to the normal travelling wave states in the two-dimensional case. An experimental scheme is suggested which may provide a new design for a cardiac defibrillator.

Controlling spiral waves and turbulent states in cardiac tissue by traveling wave perturbations

NASA Astrophysics Data System (ADS)

Wang, Peng-Ye; Xie, Ping

2000-03-01

We propose a traveling wave perturbation method to control the spatiotemporal dynamics in cardiac tissue. With a two-variable model we demonstrate that the method can successfully suppress the wave instability (alternans in action potential duration) in the one-dimensional case and convert spiral waves and turbulent states to the normal traveling wave state in the two-dimensional case. An experimental scheme is suggested which may provide a new design for a cardiac defibrillator.

A Model Framework to Estimate Impact and Cost of Genetics-Based Sterile Insect Methods for Dengue Vector Control

PubMed Central

Alphey, Nina; Alphey, Luke; Bonsall, Michael B.

2011-01-01

Vector-borne diseases impose enormous health and economic burdens and additional methods to control vector populations are clearly needed. The Sterile Insect Technique (SIT) has been successful against agricultural pests, but is not in large-scale use for suppressing or eliminating mosquito populations. Genetic RIDL technology (Release of Insects carrying a Dominant Lethal) is a proposed modification that involves releasing insects that are homozygous for a repressible dominant lethal genetic construct rather than being sterilized by irradiation, and could potentially overcome some technical difficulties with the conventional SIT technology. Using the arboviral disease dengue as an example, we combine vector population dynamics and epidemiological models to explore the effect of a program of RIDL releases on disease transmission. We use these to derive a preliminary estimate of the potential cost-effectiveness of vector control by applying estimates of the costs of SIT. We predict that this genetic control strategy could eliminate dengue rapidly from a human community, and at lower expense (approximately US$ 2∼30 per case averted) than the direct and indirect costs of disease (mean US$ 86–190 per case of dengue). The theoretical framework has wider potential use; by appropriately adapting or replacing each component of the framework (entomological, epidemiological, vector control bio-economics and health economics), it could be applied to other vector-borne diseases or vector control strategies and extended to include other health interventions. PMID:21998654

Near common-path optical fiber interferometer for potentially fast on-line microscale-nanoscale surface measurement

NASA Astrophysics Data System (ADS)

Jiang, Xiangqian; Wang, Kaiwei; Martin, Haydn

2006-12-01

We introduce a new surface measurement method for potential online application. Compared with our previous research, the new design is a significant improvement. It also features high stability because it uses a near common-path configuration. The method should be of great benefit to advanced manufacturing, especially for quality and process control in ultraprecision manufacturing and on the production line. Proof-of-concept experiments have been successfully conducted by measuring the system repeatability and the displacements of a mirror surface.

Investigation of an automatic trim algorithm for restructurable aircraft control

NASA Technical Reports Server (NTRS)

Weiss, J.; Eterno, J.; Grunberg, D.; Looze, D.; Ostroff, A.

1986-01-01

This paper develops and solves an automatic trim problem for restructurable aircraft control. The trim solution is applied as a feed-forward control to reject measurable disturbances following control element failures. Disturbance rejection and command following performances are recovered through the automatic feedback control redesign procedure described by Looze et al. (1985). For this project the existence of a failure detection mechanism is assumed, and methods to cope with potential detection and identification inaccuracies are addressed.

Probabilistic dual heuristic programming-based adaptive critic

NASA Astrophysics Data System (ADS)

Herzallah, Randa

2010-02-01

Adaptive critic (AC) methods have common roots as generalisations of dynamic programming for neural reinforcement learning approaches. Since they approximate the dynamic programming solutions, they are potentially suitable for learning in noisy, non-linear and non-stationary environments. In this study, a novel probabilistic dual heuristic programming (DHP)-based AC controller is proposed. Distinct to current approaches, the proposed probabilistic (DHP) AC method takes uncertainties of forward model and inverse controller into consideration. Therefore, it is suitable for deterministic and stochastic control problems characterised by functional uncertainty. Theoretical development of the proposed method is validated by analytically evaluating the correct value of the cost function which satisfies the Bellman equation in a linear quadratic control problem. The target value of the probabilistic critic network is then calculated and shown to be equal to the analytically derived correct value. Full derivation of the Riccati solution for this non-standard stochastic linear quadratic control problem is also provided. Moreover, the performance of the proposed probabilistic controller is demonstrated on linear and non-linear control examples.

System and method for islanding detection and prevention in distributed generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhowmik, Shibashis; Mazhari, Iman; Parkhideh, Babak

Various examples are directed to systems and methods for detecting an islanding condition at an inverter configured to couple a distributed generation system to an electrical grid network. A controller may determine a command frequency and a command frequency variation. The controller may determine that the command frequency variation indicates a potential islanding condition and send to the inverter an instruction to disconnect the distributed generation system from the electrical grid network. When the distributed generation system is disconnected from the electrical grid network, the controller may determine whether the grid network is valid.

The development and use of respirator response functions as part of a workplace exposure monitoring program for control of potential respiratory hazards.

PubMed

Maxim, L D; Allshouse, J N; Chen, S H; Treadway, J; Venturin, D

1998-04-01

The traditional hierarchy of measures for control of potential respiratory hazards in the workplace includes (in order of preference) engineering controls, workplace practices, and use of respiratory protection. Although third in this hierarchy, respirators can be an important component of the control mix-particularly for difficult-to-control jobs, as an interim measure (pending implementation of other controls), and in cases where exposure is intermittent. One of the problems associated with the use of respirators as a control measure is that valid and adequate data on respirator usage are often not available. Absent these data it is difficult to determine the practical effectiveness of respirators and exposure calculations which include the protective effect of respirators are speculative. This paper presents models (and appropriate statistical fitting techniques) suitable for quantification of respirator usage and defines three potentially useful measures of effectiveness for a respirator program. These models are illustrated with monitoring data on refractory ceramic fiber (RCF) developed as part of a Consent Agreement between the RCF industry and the U.S. Environmental Protection Agency. For this substance there are extensive and comprehensive monitoring data available. The models and methods of analysis may prove applicable for other potential respiratory hazards in the workplace. Copyright 1998 Academic Press.

Drag reduction in channel flow using nonlinear control

NASA Technical Reports Server (NTRS)

Keefe, Laurence R.

1993-01-01

Two nonlinear control schemes have been applied to the problem of drag reduction in channel flow. Both schemes have been tested using numerical simulations at a mass flux Reynolds numbers of 4408, utilizing 2D nonlinear neutral modes for goal dynamics. The OGY-method, which requires feedback, reduces drag to 60-80 percent of the turbulent value at the same Reynolds number, and employs forcing only within a thin region near the wall. The H-method, or model-based control, fails to achieve any drag reduction when starting from a fully turbulent initial condition, but shows potential for suppressing or retarding laminar-to-turbulent transition by imposing instead a transition to a low drag, nonlinear traveling wave solution to the Navier-Stokes equation. The drag in this state corresponds to that achieved by the OGY-method. Model-based control requires no feedback, but in experiments to date has required the forcing be imposed within a thicker layer than the OGY-method. Control energy expenditures in both methods are small, representing less than 0.1 percent of the uncontrolled flow's energy.

Acceptability of Positive and Punitive Discipline Methods: Comparisons among Abusive, Potentially Abusive, and Nonabusive Parents.

ERIC Educational Resources Information Center

Kelley, Mary Lou; And Others

1990-01-01

Abusive, potentially abusive, and control group parents (N=62) were presented with vignettes describing a child with either mild or severe behavior problems and asked to rate the acceptability of four discipline procedures (positive reinforcement, timeout, timeout with spanking, and spanking). Overall, parents rated positive reinforcement as more…

Electrochemical biofilm control: a review.

PubMed

Sultana, Sujala T; Babauta, Jerome T; Beyenal, Haluk

2015-01-01

One of the methods of controlling biofilms that has widely been discussed in the literature is to apply a potential or electrical current to a metal surface on which the biofilm is growing. Although electrochemical biofilm control has been studied for decades, the literature is often conflicting, as is detailed in this review. The goals of this review are: (1) to present the current status of knowledge regarding electrochemical biofilm control; (2) to establish a basis for a fundamental definition of electrochemical biofilm control and requirements for studying it; (3) to discuss current proposed mechanisms; and (4) to introduce future directions in the field. It is expected that the review will provide researchers with guidelines on comparing datasets across the literature and generating comparable datasets. The authors believe that, with the correct design, electrochemical biofilm control has great potential for industrial use.

The magnetofection method: using magnetic force to enhance gene delivery.

PubMed

Plank, Christian; Schillinger, Ulrike; Scherer, Franz; Bergemann, Christian; Rémy, Jean-Serge; Krötz, Florian; Anton, Martina; Lausier, Jim; Rosenecker, Joseph

2003-05-01

In order to enhance and target gene delivery we have previously established a novel method, termed magnetofection, which uses magnetic force acting on gene vectors that are associated with magnetic particles. Here we review the benefits, the mechanism and the potential of the method with regard to overcoming physical limitations to gene delivery. Magnetic particle chemistry and physics are discussed, followed by a detailed presentation of vector formulation and optimization work. While magnetofection does not necessarily improve the overall performance of any given standard gene transfer method in vitro, its major potential lies in the extraordinarily rapid and efficient transfection at low vector doses and the possibility of remotely controlled vector targeting in vivo.

A synchronization method for wireless acquisition systems, application to brain computer interfaces.

PubMed

Foerster, M; Bonnet, S; van Langhenhove, A; Porcherot, J; Charvet, G

2013-01-01

A synchronization method for wireless acquisition systems has been developed and implemented on a wireless ECoG recording implant and on a wireless EEG recording helmet. The presented algorithm and hardware implementation allow the precise synchronization of several data streams from several sensor nodes for applications where timing is critical like in event-related potential (ERP) studies. The proposed method has been successfully applied to obtain visual evoked potentials and compared with a reference biosignal amplifier. The control over the exact sampling frequency allows reducing synchronization errors that will otherwise accumulate during a recording. The method is scalable to several sensor nodes communicating with a shared base station.

Antecedents to Organizational Performance: Theoretical and Practical Implications for Aircraft Maintenance Officer Force Development

DTIC Science & Technology

2015-03-26

to my reader, Lieutenant Colonel Robert Overstreet, for helping solidify my research, coaching me through the statistical analysis, and positive...61  Descriptive Statistics .............................................................................................................. 61...common-method bias requires careful assessment of potential sources of bias and implementing procedural and statistical control methods. Podsakoff

Advances in the application of genetic manipulation methods to apicomplexan parasites.

PubMed

Suarez, C E; Bishop, R P; Alzan, H F; Poole, W A; Cooke, B M

2017-10-01

Apicomplexan parasites such as Babesia, Theileria, Eimeria, Cryptosporidium and Toxoplasma greatly impact animal health globally, and improved, cost-effective measures to control them are urgently required. These parasites have complex multi-stage life cycles including obligate intracellular stages. Major gaps in our understanding of the biology of these relatively poorly characterised parasites and the diseases they cause severely limit options for designing novel control methods. Here we review potentially important shared aspects of the biology of these parasites, such as cell invasion, host cell modification, and asexual and sexual reproduction, and explore the potential of the application of relatively well-established or newly emerging genetic manipulation methods, such as classical transfection or gene editing, respectively, for closing important gaps in our knowledge of the function of specific genes and proteins, and the biology of these parasites. In addition, genetic manipulation methods impact the development of novel methods of control of the diseases caused by these economically important parasites. Transient and stable transfection methods, in conjunction with whole and deep genome sequencing, were initially instrumental in improving our understanding of the molecular biology of apicomplexan parasites and paved the way for the application of the more recently developed gene editing methods. The increasingly efficient and more recently developed gene editing methods, in particular those based on the CRISPR/Cas9 system and previous conceptually similar techniques, are already contributing to additional gene function discovery using reverse genetics and related approaches. However, gene editing methods are only possible due to the increasing availability of in vitro culture, transfection, and genome sequencing and analysis techniques. We envisage that rapid progress in the development of novel gene editing techniques applied to apicomplexan parasites of veterinary interest will ultimately lead to the development of novel and more efficient methods for disease control. Published by Elsevier Ltd.

Exploiting the potential of vector control for disease prevention.

PubMed

Townson, H; Nathan, M B; Zaim, M; Guillet, P; Manga, L; Bos, R; Kindhauser, M

2005-12-01

Although vector control has proven highly effective in preventing disease transmission, it is not being used to its full potential, thereby depriving disadvantaged populations of the benefits of well tried and tested methods. Following the discovery of synthetic residual insecticides in the 1940s, large-scale programmes succeeded in bringing many of the important vector-borne diseases under control. By the late 1960s, most vector-borne diseases--with the exception of malaria in Africa--were no longer considered to be of primary public health importance. The result was that control programmes lapsed, resources dwindled, and specialists in vector control disappeared from public health units. Within two decades, many important vector-borne diseases had re-emerged or spread to new areas. The time has come to restore vector control to its key role in the prevention of disease transmission, albeit with an increased emphasis on multiple measures, whether pesticide-based or involving environmental modification, and with a strengthened managerial and operational capacity. Integrated vector management provides a sound conceptual framework for deployment of cost-effective and sustainable methods of vector control. This approach allows for full consideration of the complex determinants of disease transmission, including local disease ecology, the role of human activity in increasing risks of disease transmission, and the socioeconomic conditions of affected communities.

Exploiting the potential of vector control for disease prevention.

PubMed Central

Townson, H.; Nathan, M. B.; Zaim, M.; Guillet, P.; Manga, L.; Bos, R.; Kindhauser, M.

2005-01-01

Although vector control has proven highly effective in preventing disease transmission, it is not being used to its full potential, thereby depriving disadvantaged populations of the benefits of well tried and tested methods. Following the discovery of synthetic residual insecticides in the 1940s, large-scale programmes succeeded in bringing many of the important vector-borne diseases under control. By the late 1960s, most vector-borne diseases--with the exception of malaria in Africa--were no longer considered to be of primary public health importance. The result was that control programmes lapsed, resources dwindled, and specialists in vector control disappeared from public health units. Within two decades, many important vector-borne diseases had re-emerged or spread to new areas. The time has come to restore vector control to its key role in the prevention of disease transmission, albeit with an increased emphasis on multiple measures, whether pesticide-based or involving environmental modification, and with a strengthened managerial and operational capacity. Integrated vector management provides a sound conceptual framework for deployment of cost-effective and sustainable methods of vector control. This approach allows for full consideration of the complex determinants of disease transmission, including local disease ecology, the role of human activity in increasing risks of disease transmission, and the socioeconomic conditions of affected communities. PMID:16462987

Underpotential deposition-mediated layer-by-layer growth of thin films

DOEpatents

Wang, Jia Xu; Adzic, Radoslav R.

2015-05-19

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves the use of underpotential deposition of a first element to mediate the growth of a second material by overpotential deposition. Deposition occurs between a potential positive to the bulk deposition potential for the mediating element where a full monolayer of mediating element forms, and a potential which is less than, or only slightly greater than, the bulk deposition potential of the material to be deposited. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis. This process is especially suitable for the formation of a catalytically active layer on core-shell particles for use in energy conversion devices such as fuel cells.

Controlling ionotropic and metabotropic glutamate receptors with light: principles and potential.

PubMed

Reiner, Andreas; Levitz, Joshua; Isacoff, Ehud Y

2015-02-01

Light offers unique advantages for studying and manipulating biomolecules and the cellular processes that they control. Optical control of ionotropic and metabotropic glutamate receptors has garnered significant interest, since these receptors are central to signaling at neuronal synapses and only optical approaches provide the spatial and temporal resolution required to directly probe receptor function in cells and tissue. Following the classical method of glutamate photo-uncaging, recently developed methods have added other forms of remote control, including those with high molecular specificity and genetic targeting. These tools open the door to the direct optical control of synaptic transmission and plasticity, as well as the probing of native receptor function in intact neural circuits. Copyright © 2014 Elsevier Ltd. All rights reserved.

HIV quality report cards: impact of case-mix adjustment and statistical methods.

PubMed

Ohl, Michael E; Richardson, Kelly K; Goto, Michihiko; Vaughan-Sarrazin, Mary; Schweizer, Marin L; Perencevich, Eli N

2014-10-15

There will be increasing pressure to publicly report and rank the performance of healthcare systems on human immunodeficiency virus (HIV) quality measures. To inform discussion of public reporting, we evaluated the influence of case-mix adjustment when ranking individual care systems on the viral control quality measure. We used data from the Veterans Health Administration (VHA) HIV Clinical Case Registry and administrative databases to estimate case-mix adjusted viral control for 91 local systems caring for 12 368 patients. We compared results using 2 adjustment methods, the observed-to-expected estimator and the risk-standardized ratio. Overall, 10 913 patients (88.2%) achieved viral control (viral load ≤400 copies/mL). Prior to case-mix adjustment, system-level viral control ranged from 51% to 100%. Seventeen (19%) systems were labeled as low outliers (performance significantly below the overall mean) and 11 (12%) as high outliers. Adjustment for case mix (patient demographics, comorbidity, CD4 nadir, time on therapy, and income from VHA administrative databases) reduced the number of low outliers by approximately one-third, but results differed by method. The adjustment model had moderate discrimination (c statistic = 0.66), suggesting potential for unadjusted risk when using administrative data to measure case mix. Case-mix adjustment affects rankings of care systems on the viral control quality measure. Given the sensitivity of rankings to selection of case-mix adjustment methods-and potential for unadjusted risk when using variables limited to current administrative databases-the HIV care community should explore optimal methods for case-mix adjustment before moving forward with public reporting. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Applied dendroecology and environmental forensics. Characterizing and age dating environmental releases: fundamentals and case studies

Treesearch

Jean-Christophe Balouet; Gil Oudijk; Kevin T. Smith; Ioana Petrisor; Hakan Grudd; Bengt Stocklassa

2007-01-01

Dendroecology, or the use of ring patterns to assess the age of trees and environmental factors controlling their growth, is a well-developed method in climatologic studies. This method holds great potential as a forensic tool for age dating, contamination assessment, and characterization of releases. Moreover, the method is independent of the physical presence of...

The role of visual processing in motor learning and control: Insights from electroencephalography.

PubMed

Krigolson, Olav E; Cheng, Darian; Binsted, Gord

2015-05-01

Traditionally our understanding of goal-directed action been derived from either behavioral findings or neuroanatomically derived imaging (i.e., fMRI). While both of these approaches have proven valuable, they lack the ability to determine a direct locus of function while concurrently having the necessary temporal precision needed to understand millisecond scale neural interactions respectively. In this review we summarize some seminal behavioral findings across three broad areas (target perturbation, feed-forward control, and feedback processing) and for each discuss the application of electroencephalography (EEG) to the understanding of the temporal nature of visual cue utilization during movement planning, control, and learning using four existing scalp potentials. Specifically, we examine the appropriateness of using the N100 potential as an indicator of corrective behaviors in response to target perturbation, the N200 as an index of movement planning, the P300 potential as a metric of feed-forward processes, and the feedback-related negativity as an index of motor learning. Although these existing components have potential for insight into cognitive contributions and the timing of the neural processes that contribute to motor control further research is needed to expand the control-related potentials and to develop methods to permit their accurate characterization across a wide range of behavioral tasks. Copyright © 2015 Elsevier B.V. All rights reserved.

Diversity and Control of Spoilage Fungi in Dairy Products: An Update

PubMed Central

Valence, Florence; Mounier, Jérôme

2017-01-01

Fungi are common contaminants of dairy products, which provide a favorable niche for their growth. They are responsible for visible or non-visible defects, such as off-odor and -flavor, and lead to significant food waste and losses as well as important economic losses. Control of fungal spoilage is a major concern for industrials and scientists that are looking for efficient solutions to prevent and/or limit fungal spoilage in dairy products. Several traditional methods also called traditional hurdle technologies are implemented and combined to prevent and control such contaminations. Prevention methods include good manufacturing and hygiene practices, air filtration, and decontamination systems, while control methods include inactivation treatments, temperature control, and modified atmosphere packaging. However, despite technology advances in existing preservation methods, fungal spoilage is still an issue for dairy manufacturers and in recent years, new (bio) preservation technologies are being developed such as the use of bioprotective cultures. This review summarizes our current knowledge on the diversity of spoilage fungi in dairy products and the traditional and (potentially) new hurdle technologies to control their occurrence in dairy foods. PMID:28788096

A new multi-domain method based on an analytical control surface for linear and second-order mean drift wave loads on floating bodies

NASA Astrophysics Data System (ADS)

Liang, Hui; Chen, Xiaobo

2017-10-01

A novel multi-domain method based on an analytical control surface is proposed by combining the use of free-surface Green function and Rankine source function. A cylindrical control surface is introduced to subdivide the fluid domain into external and internal domains. Unlike the traditional domain decomposition strategy or multi-block method, the control surface here is not panelized, on which the velocity potential and normal velocity components are analytically expressed as a series of base functions composed of Laguerre function in vertical coordinate and Fourier series in the circumference. Free-surface Green function is applied in the external domain, and the boundary integral equation is constructed on the control surface in the sense of Galerkin collocation via integrating test functions orthogonal to base functions over the control surface. The external solution gives rise to the so-called Dirichlet-to-Neumann [DN2] and Neumann-to-Dirichlet [ND2] relations on the control surface. Irregular frequencies, which are only dependent on the radius of the control surface, are present in the external solution, and they are removed by extending the boundary integral equation to the interior free surface (circular disc) on which the null normal derivative of potential is imposed, and the dipole distribution is expressed as Fourier-Bessel expansion on the disc. In the internal domain, where the Rankine source function is adopted, new boundary integral equations are formulated. The point collocation is imposed over the body surface and free surface, while the collocation of the Galerkin type is applied on the control surface. The present method is valid in the computation of both linear and second-order mean drift wave loads. Furthermore, the second-order mean drift force based on the middle-field formulation can be calculated analytically by using the coefficients of the Fourier-Laguerre expansion.

A connectionist model for dynamic control

NASA Technical Reports Server (NTRS)

Whitfield, Kevin C.; Goodall, Sharon M.; Reggia, James A.

1989-01-01

The application of a connectionist modeling method known as competition-based spreading activation to a camera tracking task is described. The potential is explored for automation of control and planning applications using connectionist technology. The emphasis is on applications suitable for use in the NASA Space Station and in related space activities. The results are quite general and could be applicable to control systems in general.

Control strategies for systems with limited actuators

NASA Technical Reports Server (NTRS)

Marcopoli, Vincent R.; Phillips, Stephen M.

1994-01-01

This work investigates the effects of actuator saturation in multi-input, multi-output (MIMO) control systems. The adverse system behavior introduced by the saturation nonlinearity is viewed here as resulting from two mechanisms: controller windup - a problem caused by the discrepancy between the limited actuator commands and the corresponding control signals, and directionality - the problem of how to use nonlimited actuators when a limited condition exists. The tracking mode and Hanus methods are two common strategies for dealing with the windup problem. It is seen that while these methods alleviate windup, performance problems remain due to plant directionality. Though high gain conventional antiwindup as well as more general linear methods have the potential to address both windup and directionality, no systematic design method for these schemes has emerged; most approaches used in practice are application driven. An alternative method of addressing the directionality problem is presented which involves the introduction of a control direction preserving nonlinearity to the Hanus antiwindup system. A nonlinearity is subsequently proposed which reduces the conservation inherent in the former direction-preserving approach, improving performance. The concept of multivariable sensitivity is seen to play a key role in the success of the new method.

Telomere length and telomerase in a well-characterized sample of individuals with major depressive disorder compared to controls.

PubMed

Simon, Naomi M; Walton, Zandra E; Bui, Eric; Prescott, Jennifer; Hoge, Elizabeth; Keshaviah, Aparna; Schwarz, Noah; Dryman, Taylor; Ojserkis, Rebecca A; Kovachy, Benjamin; Mischoulon, David; Worthington, John; De Vivo, Immaculata; Fava, Maurizio; Wong, Kwok-Kin

2015-08-01

Leukocyte telomere length (LTL) is a marker of cellular turnover and oxidative stress. Studies suggest major depressive disorder (MDD) is associated with oxidative stress, but examinations of MDD and LTL have yielded mixed results, likely because of differences in measurement methods and unmeasured confounding. This study examined LTL and telomerase activity in 166 individuals with MDD compared to 166 age- and gender-matched matched controls free of any psychiatric disorder, using well-validated assays and clinical assessment methods, and controlling for a range of potential confounders. Subjects aged 18 to 70 were evaluated by trained raters and provided blood for LTL and telomerase activity measurement. LTL was assayed using Southern blot and replicated with qPCR, and telomerase activity was assayed with a repeat amplification protocol using a commercial kit. There was no significant difference in telomere length for individuals with MDD [mean (SD)=9.1 (3.0)kbp] compared to controls [mean(SD)=8.9(2.5)kbp] measured by Southern blot (p=0.65) or by confirmatory qPCR (p=0.91) assays. Controlling for potential confounders did not alter the results. Telomerase activity did not differ by MDD diagnosis overall (p=0.40), but the effect of MDD was significantly modified by gender (t(299)=2.67, p=0.0079) even after controlling for potential confounders, with telomerase activity significantly greater only in males with MDD versus controls. Our well-characterized, well-powered examination of concurrently assessed telomere length and telomerase activity in individuals with clinically significant, chronic MDD and matched controls failed to provide strong evidence of an association of MDD with shorter LTL, while telomerase activity was higher in men with MDD [corrected]. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improved model predictive control of resistive wall modes by error field estimator in EXTRAP T2R

NASA Astrophysics Data System (ADS)

Setiadi, A. C.; Brunsell, P. R.; Frassinetti, L.

2016-12-01

Many implementations of a model-based approach for toroidal plasma have shown better control performance compared to the conventional type of feedback controller. One prerequisite of model-based control is the availability of a control oriented model. This model can be obtained empirically through a systematic procedure called system identification. Such a model is used in this work to design a model predictive controller to stabilize multiple resistive wall modes in EXTRAP T2R reversed-field pinch. Model predictive control is an advanced control method that can optimize the future behaviour of a system. Furthermore, this paper will discuss an additional use of the empirical model which is to estimate the error field in EXTRAP T2R. Two potential methods are discussed that can estimate the error field. The error field estimator is then combined with the model predictive control and yields better radial magnetic field suppression.

Simulation Analysis of Computer-Controlled pressurization for Mixture Ratio Control

NASA Technical Reports Server (NTRS)

Alexander, Leslie A.; Bishop-Behel, Karen; Benfield, Michael P. J.; Kelley, Anthony; Woodcock, Gordon R.

2005-01-01

A procedural code (C++) simulation was developed to investigate potentials for mixture ratio control of pressure-fed spacecraft rocket propulsion systems by measuring propellant flows, tank liquid quantities, or both, and using feedback from these measurements to adjust propellant tank pressures to set the correct operating mixture ratio for minimum propellant residuals. The pressurization system eliminated mechanical regulators in favor of a computer-controlled, servo- driven throttling valve. We found that a quasi-steady state simulation (pressure and flow transients in the pressurization systems resulting from changes in flow control valve position are ignored) is adequate for this purpose. Monte-Carlo methods are used to obtain simulated statistics on propellant depletion. Mixture ratio control algorithms based on proportional-integral-differential (PID) controller methods were developed. These algorithms actually set target tank pressures; the tank pressures are controlled by another PID controller. Simulation indicates this approach can provide reductions in residual propellants.

Unique strategies to control reproduction in camels.

PubMed

Skidmore, J A; Morton, K M; Billah, M

2010-01-01

The reproductive efficiency of camels is low under natural pastural conditions and so the use of artifical insemination and embryo transfer are becoming increasingly important to improve their breeding potential. Methods to control their reproductive cycle are therefore essential. This review describes characteristics of the ovarian follicular wave pattern in camels and exogenous hormonal control of ovulation. It also summarizes the difficulties involved with artifical insemination and analyzing the highly gelatinous semen, and reports on the latest methods used to try and reduce the viscosity and liquefy camel semen. In addition an account is given of different hormonal and physical methods used to synchronise follicular waves, and various hormone treatments used to broaden the availability of ovulated, asynchronous and non-ovulated recipients are discussed.

The role of self-defined race/ethnicity in population structure control.

PubMed

Liu, X-Q; Paterson, A D; John, E M; Knight, J A

2006-07-01

Population-based association studies are powerful tools for the genetic mapping of complex diseases. However, this method is sensitive to potential confounding by population structure. While statistical methods that use genetic markers to detect and control for population structure have been the focus of current literature, the utility of self-defined race/ethnicity in controlling for population structure has been controversial. In this study of 1334 individuals, who self-identified as either African American, European American or Hispanic, we demonstrated that when the true underlying genetic structure and the self-defined racial/ethnic groups were roughly in agreement with each other, the self-defined race/ethnicity information was useful in the control of population structure.

Active control of surge in centrifugal compressors using magnetic thrust bearing actuation

NASA Astrophysics Data System (ADS)

Sanadgol, Dorsa

This research presents a new method for active surge control in centrifugal compressors with unshrouded impellers using a magnetic thrust bearing to modulate the impeller tip clearance. Magnetic bearings offer the potential for active control of flow instabilities. This capability is highly dependent on the sensitivity of the compressor characteristics to blade tip clearance. If the position of the shaft can be actuated with sufficient authority and speed, the induced pressure modulation makes control of surge promising. The active nature of the magnetic bearing system makes the real-time static and dynamic positioning of the rotor and therefore modulation of the impeller tip clearance possible. A theoretical model is first established that describes the sensitivity of the centrifugal compressor characteristic curve to tip clearance variations induced by axial motion of the rotor. Results from simulation of the nonlinear model for a single stage high-speed centrifugal compressor show that using the proposed control method, mass flow and pressure oscillations associated with compressor surge are quickly suppressed with acceptable tip clearance excursions, typically less than 20% of the available clearance. It is shown that it is possible to produce adequate axial excursions in the clearance between the impeller blades and the adjacent stationary shroud using a magnetic thrust bearing with practical levels of drive voltage. This surge control method would allow centrifugal compressors to reliably and safely operate with a wider range than is currently done in the field. The principal advantage of the proposed approach over conventional surge control methods lies in that, in machines already equipped with magnetic bearing, the method can potentially be implemented by simply modifying controller software. This dispenses with the need to introduce additional hardware, permitting adaptation of existing machinery at virtually no cost. In addition, since the controller is designed with the objective of keeping the trajectories on the compressor characteristic curve, the compressor performance and efficiency are no longer sacrificed by excessive recycling to achieve stability. In order to explore these conjectures experimentally, a high speed centrifugal compressor test facility with active magnetic bearings is developed. The test facility can be used for implementing the proposed surge control method and also for assessing the impeller and bearing loads at off-design conditions. This data can then be used to verify and refine analytical models used in compressor design. (Abstract shortened by UMI.)

A full potential inverse method based on a density linearization scheme for wing design

NASA Technical Reports Server (NTRS)

Shankar, V.

1982-01-01

A mixed analysis inverse procedure based on the full potential equation in conservation form was developed to recontour a given base wing to produce density linearization scheme in applying the pressure boundary condition in terms of the velocity potential. The FL030 finite volume analysis code was modified to include the inverse option. The new surface shape information, associated with the modified pressure boundary condition, is calculated at a constant span station based on a mass flux integration. The inverse method is shown to recover the original shape when the analysis pressure is not altered. Inverse calculations for weakening of a strong shock system and for a laminar flow control (LFC) pressure distribution are presented. Two methods for a trailing edge closure model are proposed for further study.

Man-in-the-control-loop simulation of manipulators

NASA Technical Reports Server (NTRS)

Chang, J. L.; Lin, Tsung-Chieh; Yae, K. Harold

1989-01-01

A method to achieve man-in-the-control-loop simulation is presented. Emerging real-time dynamics simulation suggests a potential for creating an interactive design workstation with a human operator in the control loop. The recursive formulation for multibody dynamics simulation is studied to determine requirements for man-in-the-control-loop simulation. High speed computer graphics techniques provides realistic visual cues for the simulator. Backhoe and robot arm simulations are implemented to demonstrate the capability of man-in-the-control-loop simulation.

Thrust vector control algorithm design for the Cassini spacecraft

NASA Technical Reports Server (NTRS)

Enright, Paul J.

1993-01-01

This paper describes a preliminary design of the thrust vector control algorithm for the interplanetary spacecraft, Cassini. Topics of discussion include flight software architecture, modeling of sensors, actuators, and vehicle dynamics, and controller design and analysis via classical methods. Special attention is paid to potential interactions with structural flexibilities and propellant dynamics. Controller performance is evaluated in a simulation environment built around a multi-body dynamics model, which contains nonlinear models of the relevant hardware and preliminary versions of supporting attitude determination and control functions.

Decoding spike timing: the differential reverse correlation method

PubMed Central

Tkačik, Gašper; Magnasco, Marcelo O.

2009-01-01

It is widely acknowledged that detailed timing of action potentials is used to encode information, for example in auditory pathways; however the computational tools required to analyze encoding through timing are still in their infancy. We present a simple example of encoding, based on a recent model of time-frequency analysis, in which units fire action potentials when a certain condition is met, but the timing of the action potential depends also on other features of the stimulus. We show that, as a result, spike-triggered averages are smoothed so much they do not represent the true features of the encoding. Inspired by this example, we present a simple method, differential reverse correlations, that can separate an analysis of what causes a neuron to spike, and what controls its timing. We analyze with this method the leaky integrate-and-fire neuron and show the method accurately reconstructs the model's kernel. PMID:18597928

A Control Framework for Anthropomorphic Biped Walking Based on Stabilizing Feedforward Trajectories.

PubMed

Rezazadeh, Siavash; Gregg, Robert D

2016-10-01

Although dynamic walking methods have had notable successes in control of bipedal robots in the recent years, still most of the humanoid robots rely on quasi-static Zero Moment Point controllers. This work is an attempt to design a highly stable controller for dynamic walking of a human-like model which can be used both for control of humanoid robots and prosthetic legs. The method is based on using time-based trajectories that can induce a highly stable limit cycle to the bipedal robot. The time-based nature of the controller motivates its use to entrain a model of an amputee walking, which can potentially lead to a better coordination of the interaction between the prosthesis and the human. The simulations demonstrate the stability of the controller and its robustness against external perturbations.

Psychology and the Black Experience.

ERIC Educational Resources Information Center

Thomas, Charles W.

The Social Sciences have a conceptual framework that is outside of cultural pluralism and hence, beyond a respect for the dignity of all individuals. There is a continual need to balance the control function of science with its function as a potential agent of social change. However, the scientific method is a controlled inquiry based on a…

Quality Control of an OSCE Using Generalizability Theory and Many-Faceted Rasch Measurement

ERIC Educational Resources Information Center

Iramaneerat, Cherdsak; Yudkowsky, Rachel; Myford, Carol M.; Downing, Steven M.

2008-01-01

An Objective Structured Clinical Examination (OSCE) is an effective method for evaluating competencies. However, scores obtained from an OSCE are vulnerable to many potential measurement errors that cases, items, or standardized patients (SPs) can introduce. Monitoring these sources of errors is an important quality control mechanism to ensure…

Influences of Sentence Length and Syntactic Complexity on the Speech Motor Control of Children Who Stutter

ERIC Educational Resources Information Center

MacPherson, Megan K.; Smith, Anne

2013-01-01

Purpose: To investigate the potential effects of increased sentence length and syntactic complexity on the speech motor control of children who stutter (CWS). Method: Participants repeated sentences of varied length and syntactic complexity. Kinematic measures of articulatory coordination variability and movement duration during perceptually…

Attitude coordination of multi-HUG formation based on multibody system theory

NASA Astrophysics Data System (ADS)

Xue, Dong-yang; Wu, Zhi-liang; Qi, Er-mai; Wang, Yan-hui; Wang, Shu-xin

2017-04-01

Application of multiple hybrid underwater gliders (HUGs) is a promising method for large scale, long-term ocean survey. Attitude coordination has become a requisite for task execution of multi-HUG formation. In this paper, a multibody model is presented for attitude coordination among agents in the HUG formation. The HUG formation is regarded as a multi-rigid body system. The interaction between agents in the formation is described by artificial potential field (APF) approach. Attitude control torque is composed of a conservative torque generated by orientation potential field and a dissipative term related with angular velocity. Dynamic modeling of the multibody system is presented to analyze the dynamic process of the HUG formation. Numerical calculation is carried out to simulate attitude synchronization with two kinds of formation topologies. Results show that attitude synchronization can be fulfilled based on the multibody method described in this paper. It is also indicated that different topologies affect attitude control quality with respect to energy consumption and adjusting time. Low level topology should be adopted during formation control scheme design to achieve a better control effect.

Shape-Controllable Gold Nanoparticle-MoS2 Hybrids Prepared by Tuning Edge-Active Sites and Surface Structures of MoS2 via Temporally Shaped Femtosecond Pulses.

PubMed

Zuo, Pei; Jiang, Lan; Li, Xin; Li, Bo; Xu, Yongda; Shi, Xuesong; Ran, Peng; Ma, Tianbao; Li, Dawei; Qu, Liangti; Lu, Yongfeng; Grigoropoulos, Costas P

2017-03-01

Edge-active site control of MoS 2 is crucial for applications such as chemical catalysis, synthesis of functional composites, and biochemical sensing. This work presents a novel nonthermal method to simultaneously tune surface chemical (edge-active sites) and physical (surface periodic micro/nano structures) properties of MoS 2 using temporally shaped femtosecond pulses, through which shape-controlled gold nanoparticles are in situ and self-assembly grown on MoS 2 surfaces to form Au-MoS 2 hybrids. The edge-active sites with unbound sulfurs of laser-treated MoS 2 drive the reduction of gold nanoparticles, while the surface periodic structures of laser-treated MoS 2 assist the shape-controllable growth of gold nanoparticles. The proposed novel method highlights the broad application potential of MoS 2 ; for example, these Au-MoS 2 hybrids exhibit tunable and highly sensitive SERS activity with an enhancement factor up to 1.2 × 10 7 , indicating the marked potential of MoS 2 in future chemical and biological sensing applications.

A new method to evaluate the biocontrol potential of single spore isolates of fungal entomopathogens

PubMed Central

Posada, Francisco J.; Vega, Fernando E.

2005-01-01

Fifty Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) strains isolated from the coffee berry borer were used to develop a novel screening method aimed at selecting strains with the highest biocontrol potential. The screening method is based on percent insect mortality, average survival time, mortality distribution, percent spore germination, fungal life cycle duration, and spore production on the insect. Based on these parameters, only 11 strains merited further study. The use of a sound scientific protocol for the selection of promising fungal entomopathogens should lead to more efficient use of time, labor, and financial resources in biological control programs. PMID:17119619

[Method for environmental management in paper industry based on pollution control technology simulation].

PubMed

Zhang, Xue-Ying; Wen, Zong-Guo

2014-11-01

To evaluate the reduction potential of industrial water pollutant emissions and to study the application of technology simulation in pollutant control and environment management, an Industrial Reduction Potential Analysis and Environment Management (IRPAEM) model was developed based on coupling of "material-process-technology-product". The model integrated bottom-up modeling and scenario analysis method, and was applied to China's paper industry. Results showed that under CM scenario, the reduction potentials of waster water, COD and ammonia nitrogen would reach 7 x 10(8) t, 39 x 10(4) t and 0.3 x 10(4) t, respectively in 2015, 13.8 x 10(8) t, 56 x 10(4) t and 0.5 x 10(4) t, respectively in 2020. Strengthening the end-treatment would still be the key method to reduce emissions during 2010-2020, while the reduction effect of structure adjustment would be more obvious during 2015-2020. Pollution production could basically reach the domestic or international advanced level of clean production in 2015 and 2020; the index of wastewater and ammonia nitrogen would basically meet the emission standards in 2015 and 2020 while COD would not.

Study on feasible technical potential of coal to electricity in china

NASA Astrophysics Data System (ADS)

Jia, Dexiang; Tan, Xiandong

2017-01-01

The control of bulk coal is one of the important work of air pollution control in China’s future. Existing research mainly focuses on the adaptability, economy, construction and renovation plan, and operation optimization of specific energy substitution utilization, and lacks the strategy research of long-term layout of energy substitution utilization in large area. This paper puts forward a technical potential prediction method of coal to electricity based on the thermal equivalent method, which is based on the characteristics of regional coal consumption, and combined with the trend of adaptability and economy of energy substitution utilization. Also, the paper calculates the comprehensive benefit of coal to electricity according to the varieties of energy consumption and pollutant emission level of unit energy consumption in China’s future. The research result shows that the development technical potential of coal to electricity in China is huge, about 1.8 trillion kWh, including distributed electric heating, heat pump and electric heating boiler, mainly located in North China, East China, and Northeast China. The implementation of coal to electricity has remarkable comprehensive benefits in energy conservation and emission reduction, and improvement of energy consumption safety level. Case study shows the rationality of the proposed method.

A sub-target approach to the kinodynamic motion control of a wheeled mobile robot

NASA Astrophysics Data System (ADS)

Motonaka, Kimiko; Watanabe, Keigo; Maeyama, Shoichi

2018-02-01

A mobile robot with two independently driven wheels is popular, but it is difficult to stabilize it by a continuous controller with a constant gain, due to its nonholonomic property. It is guaranteed that a nonholonomic controlled object can always be converged to an arbitrary point using a switching control method or a quasi-continuous control method based on an invariant manifold in a chained form. From this, the authors already proposed a kinodynamic controller to converge the states of such a two-wheeled mobile robot to the arbitrary target position while avoiding obstacles, by combining the control based on the invariant manifold and the harmonic potential field (HPF). On the other hand, it was confirmed in the previous research that there is a case that the robot cannot avoid the obstacle because there is no enough space to converge the current state to the target state. In this paper, we propose a method that divides the final target position into some sub-target positions and moves the robot step by step, and it is confirmed by the simulation that the robot can converge to the target position while avoiding obstacles using the proposed method.

Leaf hydraulic conductance, measured in situ, declines and recovers daily: leaf hydraulics, water potential and stomatal conductance in four temperate and three tropical tree species

Treesearch

Daniel M. Johnson; David R. Woodruff; Katherien A. McCulloh; Frederick C. Meinzer

2009-01-01

The objectives of this study were to measure Kleaf, using a rehydration kinetics method, (1) in the laboratory (under controlled conditions) across a range of water potentials to construct vulnerability curves (VC) and (2) over the course of the day in the field along with leaf water potential and stomatal conductance. The results presented here...

Mixed methods research in tobacco control with youth and young adults: A methodological review of current strategies

PubMed Central

Seaman, Elizabeth L.; Clark, Rachael S.; Plano Clark, Vicki L.

2017-01-01

Introduction Tobacco use among young people is a complex and serious global dilemma that demands innovative and diverse research approaches. The purpose of this methodological review was to examine the current use of mixed methods research in tobacco control with youth and young adult populations and to develop practical recommendations for tobacco control researchers interested in this methodology. Methods Using PubMed, we searched five peer-reviewed journals that publish tobacco control empirical literature for the use of mixed methods research to study young populations, age 12–25 years. Our team analyzed the features of each article in terms of tobacco control topic, population, youth engagement strategies, and several essential elements of mixed methods research. Results We identified 23 mixed methods studies published by authors from five different countries reported between 2004 and 2015. These 23 articles examined various topics that included tobacco use behavior, tobacco marketing and branding, and cessation among youth and young adults. The most common mixed methods approach was variations of the concurrent design in which the qualitative and quantitative strands were administered at the same time and given equal priority. This review documented several innovative applications of mixed methods research as well as challenges in the reporting of the complex research designs. Conclusions The use of mixed methods research in tobacco control has great potential for advancing the understanding of complex behavioral and sociocultural issues for all groups, especially youth and young adults. PMID:28841689

Methods for estimating population coverage of mass distribution programmes: a review of practices in relation to trachoma control.

PubMed

Cromwell, Elizabeth A; Ngondi, Jeremiah; McFarland, Deborah; King, Jonathan D; Emerson, Paul M

2012-10-01

In the context of trachoma control, population coverage with mass drug administration (MDA) using antibiotics is measured using routine data. Due to the limitations of administrative records as well as the potential for bias from incomplete or incorrect records, a literature review of coverage survey methods applied in neglected tropical disease control programmes and immunisation outreach was conducted to inform the design of coverage surveys for trachoma control. Several methods were identified, including the '30 × 7' survey method for the Expanded Programme on Immunization (EPI 30×7), other cluster random sampling (CRS) methods, lot quality assurance sampling (LQAS), purposive sampling and routine data. When compared against one another, the EPI and other CRS methods produced similar population coverage estimates, whilst LQAS, purposive sampling and use of administrative data did not generate estimates consistent with CRS. In conclusion, CRS methods present a consistent approach for MDA coverage surveys despite different methods of household selection. They merit use until standard guidelines are available. CRS methods should be used to verify population coverage derived from LQAS, purposive sampling methods and administrative reports. Copyright © 2012 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

Experimental investigation of active loads control for aircraft landing gear

NASA Technical Reports Server (NTRS)

Mcgehee, J. R.; Dreher, R. C.

1982-01-01

Aircraft dynamic loads and vibrations resulting from landing impact and from runway and taxiway unevenness are recognized as significant in causing fatigue damage, dynamic stress on the airframe, crew and passenger discomfort, and reduction of the pilot's ability to control the aircraft during ground operations. One potential method for improving operational characteistics of aircraft on the ground is the application of active control technology to the landing gears to reduce ground loads applied to the airframe. An experimental investigation was conducted which simulated the landing dynamics of a light airplane to determine the feasibility and potential of a series hydraulic active control main landing gear. The experiments involved a passive gear and an active control gear. Results of this investigation show that a series hydraulically controlled gear is feasible and that such a gear is very effective in reducing the loads transmitted by the gear to the airframe during ground operations.

Experiments in charge control at geosynchronous orbit - ATS-5 and ATS-6

NASA Technical Reports Server (NTRS)

Olsen, R. C.

1985-01-01

In connection with existing theoretical concepts, it was difficult to explain the negative potentials found in sunlight, first on Applied Technology Satellite-5 (ATS-5) and then on ATS-6. The problem became important when an association between spacecraft charging and anomalies in spacecraft behavior was observed. A study of daylight charging phenomena on ATS-6 was conducted, and an investigation was performed with the objective to determine effective methods of charge control, taking into account the feasibility to utilize the ATS-5 and ATS-6 ion engines as current sources. In the present paper, data and analysis for the ion engine experiments on ATS-5 and ATS-6 are presented. It is shown that electron emission from a satellite with insulating surfaces is not an effective method of charge control because the increase in differential charging which results limits the effectiveness of electron emitters and increases the possibility of electrostatic discharges between surfaces at different potentials.

Nondestructive assessment of pore size in foam-based hybrid composite materials

NASA Astrophysics Data System (ADS)

Chen, M. Y.; Ko, R. T.

2012-05-01

In-situ non-destructive evaluation (NDE) during processing of high temperature polymer based hybrids offers great potential to gain close control and achieve the desired level of pore size, with low overall development cost. During the polymer curing cycle, close control over the evolution of volatiles would be beneficial to avoid the presence of pores or at least control their sizes. Traditional NDE methods cannot realistically be expected to evaluate individual pores in such components, as each pore evolves and grows during curing. However, NDE techniques offer the potential to detect and quantify the macroscopic response of many pores that are undesirable or intentionally introduced into these advanced materials. In this paper, preliminary results will be presented for nondestructive assessment of pore size in foam-based hybrid composite materials using ultrasonic techniques. Pore size was evaluated through the frequency content of the ultrasonic signal. The effects of pore size on the attenuation of ultrasound were studied. Feasibility of this method was demonstrated on two types of foams with various pore sizes.

Modelling Aedes aegypti mosquito control via transgenic and sterile insect techniques: endemics and emerging outbreaks.

PubMed

Seirin Lee, S; Baker, R E; Gaffney, E A; White, S M

2013-08-21

The invasion of pest insects often changes or destroys a native ecosystem, and can result in food shortages and disease endemics. Issues such as the environmental effects of chemical control methods, the economic burden of maintaining control strategies and the risk of pest resistance still remain, and mosquito-borne diseases such as malaria and dengue fever prevail in many countries, infecting over 100 million worldwide in 2010. One environmentally friendly method for mosquito control is the Sterile Insect Technique (SIT). This species-specific method of insect control relies on the mass rearing, sterilization and release of large numbers of sterile insects. An alternative transgenic method is the Release of Insects carrying a Dominant Lethal (RIDL). Our objective is to consider contrasting control strategies for two invasive scenarios via SIT and RIDL: an endemic case and an emerging outbreak. We investigate how the release rate and size of release region influence both the potential for control success and the resources needed to achieve it, under a range of conditions and control strategies, and we discuss advantageous strategies with respect to reducing the release resources and strategy costs (in terms of control mosquito numbers) required to achieve complete eradication of wild-type mosquitoes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Electrically controlled pinning of Dzyaloshinskii-Moriya domain walls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sato, Koji; Tretiakov, Oleg A., E-mail: olegt@imr.tohoku.ac.jp; School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950

We propose a method to all-electrically control a domain-wall position in a ferromagnetic nanowire with Dzyaloshinskii-Moriya interaction. The strength of this interaction can be controlled by an external electric field, which in turn allows a fine tuning of the pinning potential of a spin-spiral domain wall. It allows to create more mobile pinning sites and can also be advantageous for ultra-low power electronics.

Radio frequency heating: a potential method for post-harvest pest control in nuts and dry products

PubMed Central

Wang, Shao-jin; Tang, Ju-ming

2004-01-01

The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applications. There is an urgent need to develop effective and economically viable alternative treatments to replace current phytosanitary and quarantine practices in order to maintain the competitiveness of US agriculture in domestic and international markets. With the reliable heating block system, the thermal death kinetics for fifth-instar codling moth, Indianmeal moth, and navel orangeworm were determined at a heating rate of 18 °C/min. A practical process protocol was developed to control the most heat resistant insect pest, fifth-instar navel orangeworm, in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF) system. RF heating to 55 °C and holding in hot air for at least 5 min resulted in 100% mortality of the fifth-instar navel orangeworm. Rancidity, sensory qualities and shell characteristics were not affected by the treatments. If this method can be economically integrated into the handling process, it should have excellent potential as a disinfestation method for in-shell walnuts. PMID:15362185

Optically controlled phased-array antenna technology for space communication systems

NASA Technical Reports Server (NTRS)

Kunath, Richard R.; Bhasin, Kul B.

1988-01-01

Using MMICs in phased-array applications above 20 GHz requires complex RF and control signal distribution systems. Conventional waveguide, coaxial cable, and microstrip methods are undesirable due to their high weight, high loss, limited mechanical flexibility and large volume. An attractive alternative to these transmission media, for RF and control signal distribution in MMIC phased-array antennas, is optical fiber. Presented are potential system architectures and their associated characteristics. The status of high frequency opto-electronic components needed to realize the potential system architectures is also discussed. It is concluded that an optical fiber network will reduce weight and complexity, and increase reliability and performance, but may require higher power.

Advances in the control of wine spoilage by Zygosaccharomyces and Dekkera/Brettanomyces.

PubMed

Zuehlke, J M; Petrova, B; Edwards, C G

2013-01-01

Understanding the characteristics of yeast spoilage, as well as the available control technologies, is vital to producing consistent, high-quality wine. Zygosaccharomyces bailii contamination may result in refermentation and CO2 production in sweet wines or grape juice concentrate, whereas Brettanomyces bruxellensis spoilage often contributes off-odors and flavors to red wines. Early detection of these yeasts by selective/differential media or genetic methods is important to minimize potential spoilage. More established methods of microbial control include sulfur dioxide, dimethyl dicarbonate, and filtration. Current research is focused on the use of chitosan, pulsed electric fields, low electric current, and ultrasonics as means to protect wine quality.

Adaptively biased molecular dynamics: An umbrella sampling method with a time-dependent potential

NASA Astrophysics Data System (ADS)

Babin, Volodymyr; Karpusenka, Vadzim; Moradi, Mahmoud; Roland, Christopher; Sagui, Celeste

We discuss an adaptively biased molecular dynamics (ABMD) method for the computation of a free energy surface for a set of reaction coordinates. The ABMD method belongs to the general category of umbrella sampling methods with an evolving biasing potential. It is characterized by a small number of control parameters and an O(t) numerical cost with simulation time t. The method naturally allows for extensions based on multiple walkers and replica exchange mechanism. The workings of the method are illustrated with a number of examples, including sugar puckering, and free energy landscapes for polymethionine and polyproline peptides, and for a short β-turn peptide. ABMD has been implemented into the latest version (Case et al., AMBER 10; University of California: San Francisco, 2008) of the AMBER software package and is freely available to the simulation community.

Active control of sound transmission through a double panel partition

NASA Astrophysics Data System (ADS)

Sas, P.; Bao, C.; Augusztinovicz, F.; Desmet, W.

1995-03-01

The feasibility of improving the insertion loss of lightweight double panel partitions by using small loudspeakers as active noise control sources inside the air gap between both panels of the partition is investigated analytically, numerically and experimentally in this paper. A theoretical analysis of the mechanisms of the fluid-structure interaction of double panel structures is presented in order to gain insight into the physical phenomena underlying the behaviour of a coupled vibro-acoustic system controlled by active methods. The analysis, based on modal coupling theory, enables one to derive some qualitative predictions concerning the potentials and limitations of the proposed approach. The theoretical analysis is valid only for geometrically simple structures. For more complex geometries, numerical simulations are required. Therefore the potential use of active noise control inside double panel structures has been analyzed by using coupled finite element and boundary element methods. To verify the conclusions drawn from the theoretical analysis and the numerical calculation and, above all, to demonstrate the potential of the proposed approach, experiments have been conducted with a laboratory set-up. The performance of the proposed approach was evaluated in terms of relative insertion loss measurements. It is shown that a considerable improvement of the insertion loss has been achieved around the lightly damped resonances of the system for the frequency range investigated (60-220 Hz).

Static shape control for adaptive wings

NASA Astrophysics Data System (ADS)

Austin, Fred; Rossi, Michael J.; van Nostrand, William; Knowles, Gareth; Jameson, Antony

1994-09-01

A theoretical method was developed and experimentally validated, to control the static shape of flexible structures by employing internal translational actuators. A finite element model of the structure, without the actuators present, is employed to obtain the multiple-input, multiple-output control-system gain matrices for actuator-load control as well as actuator-displacement control. The method is applied to the quasistatic problem of maintaining an optimum-wing cross section during various transonic-cruise flight conditions to obtain significant reductions in the shock-induced drag. Only small, potentially achievable, adaptive modifications to the profile are required. The adaptive-wing concept employs actuators as truss elements of active ribs to reshape the wing cross section by deforming the structure. Finite element analyses of an adaptive-rib model verify the controlled-structure theory. Experiments on the model were conducted, and arbitrarily selected deformed shapes were accurately achieved.

Green Jobs: Definition and Method of Appraisal of Chemical and Biological Risks

PubMed Central

Cheneval, Erwan; Busque, Marc-Antoine; Ostiguy, Claude; Lavoie, Jacques; Bourbonnais, Robert; Labrèche, France; Bakhiyi, Bouchra; Zayed, Joseph

2016-01-01

In the wake of sustainable development, green jobs are developing rapidly, changing the work environment. However a green job is not automatically a safe job. The aim of the study was to define green jobs, and to establish a preliminary risk assessment of chemical substances and biological agents for workers in Quebec. An operational definition was developed, along with criteria and sustainable development principles to discriminate green jobs from regular jobs. The potential toxicity or hazard associated with their chemical and biological exposures was assessed, and the workers’ exposure appraised using an expert assessment method. A control banding approach was then used to assess risks for workers in selected green jobs. A double entry model allowed us to set priorities in terms of chemical or biological risk. Among jobs that present the highest risk potential, several are related to waste management. The developed method is flexible and could be adapted to better appraise the risks that workers are facing or to propose control measures. PMID:26718400

Artificial Intelligence Based Control Power Optimization on Tailless Aircraft. [ARMD Seedling Fund Phase I

NASA Technical Reports Server (NTRS)

Gern, Frank; Vicroy, Dan D.; Mulani, Sameer B.; Chhabra, Rupanshi; Kapania, Rakesh K.; Schetz, Joseph A.; Brown, Derrell; Princen, Norman H.

2014-01-01

Traditional methods of control allocation optimization have shown difficulties in exploiting the full potential of controlling large arrays of control devices on innovative air vehicles. Artificial neutral networks are inspired by biological nervous systems and neurocomputing has successfully been applied to a variety of complex optimization problems. This project investigates the potential of applying neurocomputing to the control allocation optimization problem of Hybrid Wing Body (HWB) aircraft concepts to minimize control power, hinge moments, and actuator forces, while keeping system weights within acceptable limits. The main objective of this project is to develop a proof-of-concept process suitable to demonstrate the potential of using neurocomputing for optimizing actuation power for aircraft featuring multiple independently actuated control surfaces. A Nastran aeroservoelastic finite element model is used to generate a learning database of hinge moment and actuation power characteristics for an array of flight conditions and control surface deflections. An artificial neural network incorporating a genetic algorithm then uses this training data to perform control allocation optimization for the investigated aircraft configuration. The phase I project showed that optimization results for the sum of required hinge moments are improved by more than 12% over the best Nastran solution by using the neural network optimization process.

Method for synthesizing N.sub.2 O.sub.5

DOEpatents

McGuire, Raymond R.; Coon, Clifford L.; Harrar, Jackson E.; Pearson, Richard K.

1985-01-01

A method and apparatus for electrochemically synthesizing N.sub.2 O.sub.5 includes oxidizing a solution of N.sub.2 O.sub.4 /HNO.sub.3 at an anode, while maintaining a controlled potential between the N.sub.2 O.sub.4 /HNO.sub.3 solution and the anode. A potential of about 1.35 to 2.0 V vs. SCE is preferred, while a potential of about 1.80 V vs. SCE is most preferred. Thereafter, the N.sub.2 O.sub.5 is reacted with either 1.5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DADN) or 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane (TAT) to form cyclotetramethylenetetraamine (HMX).

Method for synthesizing HMX

DOEpatents

McGuire, Raymond R.; Coon, Clifford L.; Harrar, Jackson E.; Pearson, Richard K.

1984-01-01

A method and apparatus for electrochemically synthesizing N.sub.2 O.sub.5 cludes oxidizing a solution of N.sub.2 O.sub.4 /HNO.sub.3 at an anode, while maintaining a controlled potential between the N.sub.2 O.sub.4 /HNO.sub.3 solution and the anode. A potential of about 1.35 to 2.0 V vs. SCE is preferred, while a potential of about 1.80 V vs. SCE is most preferred. Thereafter, the N.sub.2 O.sub.5 is reacted with either 1.5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DADN) or 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane (TAT) to form cyclotetramethylenetetraamine (HMX).

Cell fate reprogramming by control of intracellular network dynamics

NASA Astrophysics Data System (ADS)

Zanudo, Jorge G. T.; Albert, Reka

Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell's fate, such as disease therapeutics and stem cell reprogramming. Although the topic of controlling the dynamics of a system has a long history in control theory, most of this work is not directly applicable to intracellular networks. Here we present a network control method that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our control method takes advantage of certain function-dependent network components and their relation to steady states in order to identify control targets, which are guaranteed to drive any initial state to the target state with 100% effectiveness and need to be applied only transiently for the system to reach and stay in the desired state. We illustrate our method's potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments. This work was supported by NSF Grant PHY 1205840.

Control theory based airfoil design using the Euler equations

NASA Technical Reports Server (NTRS)

Jameson, Antony; Reuther, James

1994-01-01

This paper describes the implementation of optimization techniques based on control theory for airfoil design. In our previous work it was shown that control theory could be employed to devise effective optimization procedures for two-dimensional profiles by using the potential flow equation with either a conformal mapping or a general coordinate system. The goal of our present work is to extend the development to treat the Euler equations in two-dimensions by procedures that can readily be generalized to treat complex shapes in three-dimensions. Therefore, we have developed methods which can address airfoil design through either an analytic mapping or an arbitrary grid perturbation method applied to a finite volume discretization of the Euler equations. Here the control law serves to provide computationally inexpensive gradient information to a standard numerical optimization method. Results are presented for both the inverse problem and drag minimization problem.

Closed Loop Active Flow Separation Detection and Control in a Multistage Compressor

NASA Technical Reports Server (NTRS)

Bright, Michelle M.; Culley, Dennis E.; Braunscheidel, Edward P.; Welch, Gerard E.

2005-01-01

Active closed loop flow control was successfully demonstrated on a full annulus of stator vanes in a low speed axial compressor. Two independent methods of detecting separated flow conditions on the vane suction surface were developed. The first technique detects changes in static pressure along the vane suction surface, while the second method monitors variation in the potential field of the downstream rotor. Both methods may feasibly be used in future engines employing embedded flow control technology. In response to the detection of separated conditions, injection along the suction surface of each vane was used. Injected mass flow on the suction surface of stator vanes is known to reduce separation and the resulting limitation on static pressure rise due to lowered diffusion in the vane passage. A control algorithm was developed which provided a proportional response of the injected mass flow to the degree of separation, thereby minimizing the performance penalty on the compressor system.

Noise-free recovery of optodigital encrypted and multiplexed images.

PubMed

Henao, Rodrigo; Rueda, Edgar; Barrera, John F; Torroba, Roberto

2010-02-01

We present a method that allows storing multiple encrypted data using digital holography and a joint transform correlator architecture with a controllable angle reference wave. In this method, the information is multiplexed by using a key and a different reference wave angle for each object. In the recovering process, the use of different reference wave angles prevents noise produced by the nonrecovered objects from being superimposed on the recovered object; moreover, the position of the recovered object in the exit plane can be fully controlled. We present the theoretical analysis and the experimental results that show the potential and applicability of the method.

Inductive Double-Contingency Analysis of UO2 Powder Bulk Blending Operations at a Commercial Fuel Plant (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skiles, S. K.

1994-12-22

An inductive double-contingency analysis (DCA) method developed by the criticality safety function at the Savannah River Site, was applied in Criticality Safety Evaluations (CSEs) of five major plant process systems at the Westinghouse Electric Corporation`s Commercial Nuclear Fuel Manufacturing Plant in Columbia, South Carolina (WEC-Cola.). The method emphasizes a thorough evaluation of the controls intended to provide barriers against criticality for postulated initiating events, and has been demonstrated effective at identifying common mode failure potential and interdependence among multiple controls. A description of the method and an example of its application is provided.

Nasal Oxytocin for Social Deficits in Childhood Autism: A Randomized Controlled Trial

ERIC Educational Resources Information Center

Dadds, Mark R.; MacDonald, Elayne; Cauchi, Avril; Williams, Katrina; Levy, Florence; Brennan, John

2014-01-01

The last two decades have witnessed a surge in research investigating the application of oxytocin as a method of enhancing social behaviour in humans. Preliminary evidence suggests oxytocin may have potential as an intervention for autism. We evaluated a 5-day "live-in" intervention using a double-blind randomized control trial. 38 male…

Translating Principles of Neural Plasticity into Research on Speech Motor Control Recovery and Rehabilitation

ERIC Educational Resources Information Center

Ludlow, Christy L.; Hoit, Jeannette; Kent, Raymond; Ramig, Lorraine O.; Shrivastav, Rahul; Strand, Edythe; Yorkston, Kathryn; Sapienza, Christine M.

2008-01-01

Purpose: To review the principles of neural plasticity and make recommendations for research on the neural bases for rehabilitation of neurogenic speech disorders. Method: A working group in speech motor control and disorders developed this report, which examines the potential relevance of basic research on the brain mechanisms involved in neural…

Biology and Control of Insect and Related Pests of Livestock in Wyoming. MP-23.

ERIC Educational Resources Information Center

Lloyd, John E.

This document provides information that a potential insecticide applicator can utilize to safely and effectively control insects and related pests of livestock. The first section of the manual discusses the general methods of preparation and application of insecticides. The second section concerns itself with the recognition of insect problems,…

Psychological Vulnerability in Children Next-Born after Stillbirth: A Case-Control Follow-Up Study

ERIC Educational Resources Information Center

Turton, Penelope; Badenhorst, William; Pawlby, Susan; White, Sarah; Hughes, Patricia

2009-01-01

Background: Case studies and anecdotal accounts suggest that perinatal loss may impact upon other children in the family, including those born subsequent to loss. However, there is a dearth of systematically collected quantitative data on this potentially vulnerable group. Methods: Case-controlled follow-up of 52 mothers with history of stillbirth…

Quantum dynamics of light-driven chiral molecular motors.

PubMed

Yamaki, Masahiro; Nakayama, Shin-ichiro; Hoki, Kunihito; Kono, Hirohiko; Fujimura, Yuichi

2009-03-21

The results of theoretical studies on quantum dynamics of light-driven molecular motors with internal rotation are presented. Characteristic features of chiral motors driven by a non-helical, linearly polarized electric field of light are explained on the basis of symmetry argument. The rotational potential of the chiral motor is characterized by a ratchet form. The asymmetric potential determines the directional motion: the rotational direction is toward the gentle slope of the asymmetric potential. This direction is called the intuitive direction. To confirm the unidirectional rotational motion, results of quantum dynamical calculations of randomly-oriented molecular motors are presented. A theoretical design of the smallest light-driven molecular machine is presented. The smallest chiral molecular machine has an optically driven engine and a running propeller on its body. The mechanisms of transmission of driving forces from the engine to the propeller are elucidated by using a quantum dynamical treatment. The results provide a principle for control of optically-driven molecular bevel gears. Temperature effects are discussed using the density operator formalism. An effective method for ultrafast control of rotational motions in any desired direction is presented with the help of a quantum control theory. In this method, visible or UV light pulses are applied to drive the motor via an electronic excited state. A method for driving a large molecular motor consisting of an aromatic hydrocarbon is presented. The molecular motor is operated by interactions between the induced dipole of the molecular motor and the electric field of light pulses.

Towards using musculoskeletal models for intelligent control of physically assistive robots.

PubMed

Carmichael, Marc G; Liu, Dikai

2011-01-01

With the increasing number of robots being developed to physically assist humans in tasks such as rehabilitation and assistive living, more intelligent and personalized control systems are desired. In this paper we propose the use of a musculoskeletal model to estimate the strength of the user, from which information can be utilized to improve control schemes in which robots physically assist humans. An optimization model is developed utilizing a musculoskeletal model to estimate human strength in a specified dynamic state. Results of this optimization as well as methods of using it to observe muscle-based weaknesses in task space are presented. Lastly potential methods and problems in incorporating this model into a robot control system are discussed.

Predictive Thermal Control Applied to HabEx

NASA Technical Reports Server (NTRS)

Brooks, Thomas E.

2017-01-01

Exoplanet science can be accomplished with a telescope that has an internal coronagraph or with an external starshade. An internal coronagraph architecture requires extreme wavefront stability (10 pm change/10 minutes for 10(exp -10) contrast), so every source of wavefront error (WFE) must be controlled. Analysis has been done to estimate the thermal stability required to meet the wavefront stability requirement. This paper illustrates the potential of a new thermal control method called predictive thermal control (PTC) to achieve the required thermal stability. A simple development test using PTC indicates that PTC may meet the thermal stability requirements. Further testing of the PTC method in flight-like environments will be conducted in the X-ray and Cryogenic Facility (XRCF) at Marshall Space Flight Center (MSFC).

Predictive thermal control applied to HabEx

NASA Astrophysics Data System (ADS)

Brooks, Thomas E.

2017-09-01

Exoplanet science can be accomplished with a telescope that has an internal coronagraph or with an external starshade. An internal coronagraph architecture requires extreme wavefront stability (10 pm change/10 minutes for 10-10 contrast), so every source of wavefront error (WFE) must be controlled. Analysis has been done to estimate the thermal stability required to meet the wavefront stability requirement. This paper illustrates the potential of a new thermal control method called predictive thermal control (PTC) to achieve the required thermal stability. A simple development test using PTC indicates that PTC may meet the thermal stability requirements. Further testing of the PTC method in flight-like environments will be conducted in the X-ray and Cryogenic Facility (XRCF) at Marshall Space Flight Center (MSFC).

Mixed methods research in tobacco control with youth and young adults: A methodological review of current strategies.

PubMed

Fryer, Craig S; Seaman, Elizabeth L; Clark, Rachael S; Plano Clark, Vicki L

2017-01-01

Tobacco use among young people is a complex and serious global dilemma that demands innovative and diverse research approaches. The purpose of this methodological review was to examine the current use of mixed methods research in tobacco control with youth and young adult populations and to develop practical recommendations for tobacco control researchers interested in this methodology. Using PubMed, we searched five peer-reviewed journals that publish tobacco control empirical literature for the use of mixed methods research to study young populations, age 12-25 years. Our team analyzed the features of each article in terms of tobacco control topic, population, youth engagement strategies, and several essential elements of mixed methods research. We identified 23 mixed methods studies published by authors from five different countries reported between 2004 and 2015. These 23 articles examined various topics that included tobacco use behavior, tobacco marketing and branding, and cessation among youth and young adults. The most common mixed methods approach was variations of the concurrent design in which the qualitative and quantitative strands were administered at the same time and given equal priority. This review documented several innovative applications of mixed methods research as well as challenges in the reporting of the complex research designs. The use of mixed methods research in tobacco control has great potential for advancing the understanding of complex behavioral and sociocultural issues for all groups, especially youth and young adults.

Mamdani Fuzzy System for Indoor Autonomous Mobile Robot

NASA Astrophysics Data System (ADS)

Khan, M. K. A. Ahamed; Rashid, Razif; Elamvazuthi, I.

2011-06-01

Several control algorithms for autonomous mobile robot navigation have been proposed in the literature. Recently, the employment of non-analytical methods of computing such as fuzzy logic, evolutionary computation, and neural networks has demonstrated the utility and potential of these paradigms for intelligent control of mobile robot navigation. In this paper, Mamdani fuzzy system for an autonomous mobile robot is developed. The paper begins with the discussion on the conventional controller and then followed by the description of fuzzy logic controller in detail.

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.

Differentiating Medicated Patients Suffering from Major Depressive Disorder from Healthy Controls by Spot Urine Measurement of Monoamines and Steroid Hormones

PubMed Central

Wijaya, Chandra S.; Lee, Jovia J. Z.; Husain, Syeda F.; Ho, Cyrus S. H.; McIntyre, Roger S.; Tam, Wilson W.

2018-01-01

Introduction: Major Depressive Disorder (MDD) is a common psychiatric disorder. Currently, there is no objective, cost-effective and non-invasive method to measure biological markers related to the pathogenesis of MDD. Previous studies primarily focused on urinary metabolite markers which are not proximal to the pathogenesis of MDD. Herein, we compare urinary monoamines, steroid hormones and the derived ratios amongst MDD when compared to healthy controls. Methods: Morning urine samples of medicated patients suffering from MDD (n = 47) and healthy controls (n = 41) were collected. Enzyme-linked immunosorbent assay (ELISA) was performed to measure five biomarkers: cortisol, dopamine, noradrenaline, serotonin and sulphate derivative of dehydroepiandrosterone (DHEAS). The mean urinary levels and derived ratios of monoamines and steroid hormones were compared between patients and controls to identify potential biomarkers. The receiver operative characteristic curve (ROC) analysis was conducted to evaluate the diagnostic performance of potential biomarkers. Results: Medicated patients with MDD showed significantly higher spot urine ratio of DHEAS/serotonin (1.56 vs. 1.19, p = 0.004) and lower ratio of serotonin/dopamine (599.71 vs. 888.60, p = 0.008) than healthy controls. A spot urine serotonin/dopamine ratio cut-off of >667.38 had a sensitivity of 73.2% and specificity of 51.1%. Conclusions: Our results suggest that spot urine serotonin/dopamine ratio can be used as an objective diagnostic method for adults with MDD. PMID:29701669

Morphological alterations in the synganglion and integument of Rhipicephalus sanguineus ticks exposed to aqueous extracts of neem leaves (Azadirachta indica A. JUSS).

PubMed

Remedio, R N; Nunes, P H; Anholeto, L A; Camargo-Mathias, M I

2014-12-01

Currently, the necessity of controlling infestation by ticks, especially by Rhipicephalus sanguineus, has led researchers and public health managers around the world to search for new and more efficient control methods. This way, we can highlight neem (Azadirachta indica A. Juss) leaf, bark, and seed extracts, which have been very effective on tick control, and moreover causing less damage to the environment and to the host. This study showed the potential of neem as a control method for R. sanguineus through morphological and morphometric evaluation of the integument and synganglion of females, in semiengorged stage. To attain this, routine techniques of optical microscopy, scanning electron microscopy and morphometry of the cuticle and subcuticle of the integument were applied. Expressive morphological alterations were observed in both organs, presenting a dose-dependent effect. Integument epithelial cells and nerve cells of the synganglion showed signs of cell vacuolation, dilated intercellular boundaries, and cellular disorganization, alterations not previously reported in studies with neem. In addition, variations in subcuticle thickness were also observed. In general, the effects of neem are multiple, and affect the morphology and physiology of target animals in various ways. The results presented in this work are the first evidence of its effects in the coating and nervous system of ticks, thus allowing an indication of neem aqueous extracts as a potential control method of the brown dog tick and opening new perspectives on acaricide use. © 2014 Wiley Periodicals, Inc.

BCIs in the Laboratory and at Home: The Wadsworth Research Program

NASA Astrophysics Data System (ADS)

Sellers, Eric W.; McFarland, Dennis J.; Vaughan, Theresa M.; Wolpaw, Jonathan R.

Many people with severe motor disabilities lack the muscle control that would allow them to rely on conventional methods of augmentative communication and control. Numerous studies over the past two decades have indicated that scalp-recorded electroencephalographic (EEG) activity can be the basis for non-muscular communication and control systems, commonly called brain-computer interfaces (BCIs) [55]. EEG-based BCI systems measure specific features of EEG activity and translate these features into device commands. The most commonly used features are rhythms produced by the sensorimotor cortex [38, 55, 56, 59], slow cortical potentials [4, 5, 23], and the P300 event-related potential [12, 17, 46]. Systems based on sensorimotor rhythms or slow cortical potentials use oscillations or transient signals that are spontaneous in the sense that they are not dependent on specific sensory events. Systems based on the P300 response use transient signals in the EEG that are elicited by specific stimuli.

R-Index Measure of Microencapsulated Tributyrin in Gamma-Cyclodextrin Influenced by Drying Method.

PubMed

Donovan, Joseph D; Lee, Soo-Yeun; Lee, Youngsoo

2016-09-01

Microencapsulation is commonly used in the food industry for a variety of purposes including added ingredient functionally and taste-masking for those ingredients with negative sensory qualities. Tributyrin (TB), a source intestinally-essential butyric acid, possesses negative aroma (cheesy, fecal) and taste (bitter) qualities. This has significantly limited its use in food applications for the potential improvement of intestinal health. Utilizing spray drying and low-temperature oven drying, microcapsules containing TB were produced using whey (WPI), WPI and inulin, and gamma-cyclodextrin (GCD). To determine how microcapsule formulation and drying method affected the perception of TB relative to a control, microencapsulated and free TB were added to an infant formula system and evaluated using the rating method to determine R-index measures. Pooled R-index measures (α = 0.01, 2-tailed, and n = 170) indicated that the only microcapsule not significantly different from the control (R-index below 57.95%) was the GCD and TB oven dried (GCT OD) microcapsule. All other WPI, WPI-inulin, and GCD and TB spray-dried (GCT SD) microcapsules were all significantly different from the control. Average individual R-index results indicated that all microcapsules in infant formula, except for GCT OD, were significantly different (P < 0.01) from the control formula but not from free TB. Spray drying may create microcapsules with surface TB and disturb the GCD-TB complex, allowing free, and surface TB to be perceived by the panelists. The GCT OD microcapsule has the potential to be used for the potential oral treatment of intestinal disorders in functional food applications without the negative sensory qualities of TB. © 2016 Institute of Food Technologists®

Experimental treatment of neoplasic diseases and tumors with iono magnetic therapy

NASA Astrophysics Data System (ADS)

Rizsanyi, Elek Karsay; Quiróz, David Lavan; Huamaccto, Carlos Levano; Marroquín, Erwin Guerra

2001-10-01

The Iono Magnetic Therapy is a alternative control method for cell growth population in pancreas and cerebral cancer. The magnetic field applied to cells with cancer decrease the growth of this cells or their multiplication. We observed a potential difference opposite to cell potential and propose that the ionic interchange is very slow tampering with cell growth in cancer.

Inversion of potential field data using the finite element method on parallel computers

NASA Astrophysics Data System (ADS)

Gross, L.; Altinay, C.; Shaw, S.

2015-11-01

In this paper we present a formulation of the joint inversion of potential field anomaly data as an optimization problem with partial differential equation (PDE) constraints. The problem is solved using the iterative Broyden-Fletcher-Goldfarb-Shanno (BFGS) method with the Hessian operator of the regularization and cross-gradient component of the cost function as preconditioner. We will show that each iterative step requires the solution of several PDEs namely for the potential fields, for the adjoint defects and for the application of the preconditioner. In extension to the traditional discrete formulation the BFGS method is applied to continuous descriptions of the unknown physical properties in combination with an appropriate integral form of the dot product. The PDEs can easily be solved using standard conforming finite element methods (FEMs) with potentially different resolutions. For two examples we demonstrate that the number of PDE solutions required to reach a given tolerance in the BFGS iteration is controlled by weighting regularization and cross-gradient but is independent of the resolution of PDE discretization and that as a consequence the method is weakly scalable with the number of cells on parallel computers. We also show a comparison with the UBC-GIF GRAV3D code.

The use of current source density as electrophysiological correlates in neuropsychiatric disorders: a review of human studies

PubMed Central

Kamarajan, Chella; Pandey, Ashwini K.; Chorlian, David B.; Porjesz, Bernice

2014-01-01

The use of current source density (CSD), the Laplacian of the scalp surface voltage, to map the electrical activity of the brain is a powerful method in studies of cognitive and affective phenomena. During the last few decades, mapping of CSD has been successfully applied to characterize several neuropsychiatric conditions such as alcoholism, schizophrenia, depression, anxiety disorders, childhood/developmental disorders, and neurological conditions (i.e., epilepsy and brain lesions) using electrophysiological data from resting state and during cognitive performance. Use of CSD and Laplacian measures has proven effective in elucidating topographic and activation differences between groups: i) patients with a specific diagnosis vs. healthy controls, ii) subjects at high risk for a specific diagnosis vs. low risk or normal controls, and iii) patients with specific symptom(s) vs. patients without these symptom(s). The present review outlines and summarizes the studies that have employed CSD measures in investigating several neuropsychiatric conditions. The advantages and potential of CSD-based methods in clinical and research applications along with some of the limitations inherent in the CSD-based methods are discussed in the review, as well as future directions to expand the implementation of CSD to other potential clinical applications. As CSD methods have proved to be more advantageous than using scalp potential data to understand topographic and source activations, its clinical applications offer promising potential, not only for a better understanding of a range of psychiatric conditions, but also for a variety of focal neurological disorders, including epilepsy and other conditions involving brain lesions and surgical interventions. PMID:25448264

Implementation of a Biaxial Resonant Fatigue Test Method on a Large Wind Turbine Blade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snowberg, D.; Dana, S.; Hughes, S.

2014-09-01

A biaxial resonant test method was utilized to simultaneously fatigue test a wind turbine blade in the flap and edge (lead-lag) direction. Biaxial resonant blade fatigue testing is an accelerated life test method utilizing oscillating masses on the blade; each mass is independently oscillated at the respective flap and edge blade resonant frequency. The flap and edge resonant frequency were not controlled, nor were they constant for this demonstrated test method. This biaxial resonant test method presented surmountable challenges in test setup simulation, control and data processing. Biaxial resonant testing has the potential to complete test projects faster than single-axismore » testing. The load modulation during a biaxial resonant test may necessitate periodic load application above targets or higher applied test cycles.« less

Population control methods in stochastic extinction and outbreak scenarios.

PubMed

Segura, Juan; Hilker, Frank M; Franco, Daniel

2017-01-01

Adaptive limiter control (ALC) and adaptive threshold harvesting (ATH) are two related control methods that have been shown to stabilize fluctuating populations. Large variations in population abundance can threaten the constancy and the persistence stability of ecological populations, which may impede the success and efficiency of managing natural resources. Here, we consider population models that include biological mechanisms characteristic for causing extinctions on the one hand and pest outbreaks on the other hand. These models include Allee effects and the impact of natural enemies (as is typical of forest defoliating insects). We study the impacts of noise and different levels of biological parameters in three extinction and two outbreak scenarios. Our results show that ALC and ATH have an effect on extinction and outbreak risks only for sufficiently large control intensities. Moreover, there is a clear disparity between the two control methods: in the extinction scenarios, ALC can be effective and ATH can be counterproductive, whereas in the outbreak scenarios the situation is reversed, with ATH being effective and ALC being potentially counterproductive.

Spacecraft applications of advanced global positioning system technology

NASA Technical Reports Server (NTRS)

Huth, Gaylord; Dodds, James; Udalov, Sergei; Austin, Richard; Loomis, Peter; Duboraw, I. Newton, III

1988-01-01

The purpose of this study was to evaluate potential uses of Global Positioning System (GPS) in spacecraft applications in the following areas: attitude control and tracking; structural control; traffic control; and time base definition (synchronization). Each of these functions are addressed. Also addressed are the hardware related issues concerning the application of GPS technology and comparisons are provided with alternative instrumentation methods for specific functions required for an advanced low earth orbit spacecraft.

Alpha Training: A Technique for Changing Behavior in Children and Adults.

ERIC Educational Resources Information Center

Matthews, Doris B.

Several counseling methods have attempted to help individuals change their behavior patterns. Techniques that teach control of the internal functions of the mind, body, and emotions are designed to allow the individual to reach his/her potential. Alpha training is one such method that is concerned with a brain wave pattern yielding an alert,…

Empirical mode decomposition processing to improve multifocal-visual-evoked-potential signal analysis in multiple sclerosis

PubMed Central

2018-01-01

Objective To study the performance of multifocal-visual-evoked-potential (mfVEP) signals filtered using empirical mode decomposition (EMD) in discriminating, based on amplitude, between control and multiple sclerosis (MS) patient groups, and to reduce variability in interocular latency in control subjects. Methods MfVEP signals were obtained from controls, clinically definitive MS and MS-risk progression patients (radiologically isolated syndrome (RIS) and clinically isolated syndrome (CIS)). The conventional method of processing mfVEPs consists of using a 1–35 Hz bandpass frequency filter (XDFT). The EMD algorithm was used to decompose the XDFT signals into several intrinsic mode functions (IMFs). This signal processing was assessed by computing the amplitudes and latencies of the XDFT and IMF signals (XEMD). The amplitudes from the full visual field and from ring 5 (9.8–15° eccentricity) were studied. The discrimination index was calculated between controls and patients. Interocular latency values were computed from the XDFT and XEMD signals in a control database to study variability. Results Using the amplitude of the mfVEP signals filtered with EMD (XEMD) obtains higher discrimination index values than the conventional method when control, MS-risk progression (RIS and CIS) and MS subjects are studied. The lowest variability in interocular latency computations from the control patient database was obtained by comparing the XEMD signals with the XDFT signals. Even better results (amplitude discrimination and latency variability) were obtained in ring 5 (9.8–15° eccentricity of the visual field). Conclusions Filtering mfVEP signals using the EMD algorithm will result in better identification of subjects at risk of developing MS and better accuracy in latency studies. This could be applied to assess visual cortex activity in MS diagnosis and evolution studies. PMID:29677200

Regenerated cellulose capsules for controlled drug delivery: Part III. Developing a fabrication method and evaluating extemporaneous utility for controlled-release.

PubMed

Bhatt, Bhavik; Kumar, Vijay

2016-08-25

In this article, we describe a method to utilize cellulose dissolved in dimethyl sulfoxide and paraformaldehyde solvent system to fabricate two-piece regenerated cellulose hard shell capsules for their potential use as an oral controlled drug delivery a priori vehicle. A systematic evaluation of solution rheology as well as resulting capsule mechanical, visual and thermal analysis was performed to develop a suitable method to repeatedly fabricate RC hard shell capsule halves. Because of the viscoelastic nature of the cellulose solution, a combination of dip-coating and casting method, herein referred to as dip-casting method, was developed. The dip-casting method was formalized by utilizing two-stage 2(2) full factorial design approach in order to determine a suitable approach to fabricate capsules with minimal variability. Thermal annealing is responsible for imparting shape rigidity of the capsules. Proof-of-concept analysis for the utility of these capsules in controlled drug delivery was performed by evaluating the release of KCl from them as well as from commercially available USP equivalent formulations. Release of KCl from cellulose capsules was comparable to extended release capsule formulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Controlling matter waves in momentum space

NASA Astrophysics Data System (ADS)

Lin, De-Hone

2014-07-01

The transformation design method of momentum for matter waves in a harmonic trap is proposed. As applications, we design (1) a momentum invisibility cloak to control the distribution of a wave function in momentum space, (2) a quantum localization cloak that localizes a matter wave around zero momentum, and (3) the unusual quantum states of momentum space. Comprehension of these momentum cloaks in position space through the Fourier transformation is presented. In contrast to the construct of quantum cloaks in position space, the momentum cloaks presented here can only be reached by controlling the spring parameter of the trap and offering a potential there, without needing to control the effective mass of quantum particles themselves. The presented discussions also provide a possible inspiration to help localize and maintain a quantum state in momentum space by way of controlling the shape of a trap and a supplied potential.

30 CFR 250.1606 - Control of wells.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... and safest drilling technologies and state-of-the-art methods to evaluate and minimize the potential..., equipment, natural resources, and the environment. ...

30 CFR 250.1606 - Control of wells.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... and safest drilling technologies and state-of-the-art methods to evaluate and minimize the potential..., equipment, natural resources, and the environment. ...

30 CFR 250.1606 - Control of wells.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... and safest drilling technologies and state-of-the-art methods to evaluate and minimize the potential..., equipment, natural resources, and the environment. ...

Assessment of alternative disposal methods to reduce greenhouse gas emissions from municipal solid waste in India.

PubMed

Yedla, Sudhakar; Sindhu, N T

2016-06-01

Open dumping, the most commonly practiced method of solid waste disposal in Indian cities, creates serious environment and economic challenges, and also contributes significantly to greenhouse gas emissions. The present article attempts to analyse and identify economically effective ways to reduce greenhouse gas emissions from municipal solid waste. The article looks at the selection of appropriate methods for the control of methane emissions. Multivariate functional models are presented, based on theoretical considerations as well as the field measurements to forecast the greenhouse gas mitigation potential for all the methodologies under consideration. Economic feasibility is tested by calculating the unit cost of waste disposal for the respective disposal process. The purpose-built landfill system proposed by Yedla and Parikh has shown promise in controlling greenhouse gas and saving land. However, these studies show that aerobic composting offers the optimal method, both in terms of controlling greenhouse gas emissions and reducing costs, mainly by requiring less land than other methods. © The Author(s) 2016.

Identification of Biocontrol Agents to Control the Fungal Pathogen, Geomyces destructans, in Bats

NASA Astrophysics Data System (ADS)

Braunstein, S.; Cheng, T.

2013-12-01

The fungal pathogen Geomyces destructans (Gd) causes the disease White-nose Syndrome (WNS) in bats and is estimated to have killed millions of bats since its emergence in North America in 2006. Gd is predicted to cause the local extinction of at least three bat species if rates of decline continue unabated. Given the devastating impacts of Gd to bat populations, identifying a viable method for controlling the pathogen is pertinent for conservation of affected bat species. Our work focuses on identifying naturally-occurring skin bacteria on bats that are antagonistic to Gd that could potentially be used as a biocontrol. We cultured bacteria from skin swabs taken from wild bats (Myotis lucifugus, Eptesicus fuscus, Myotis sodalis, Perimyotis subflavus). We conducted challenge experiments to identify bacterial strains that inhibited Gd growth. Bacteria that exhibited antifungal properties were identified using 16S and gyrB markers. Our methods identified several bacteria in the Pseudomonas fluorescens complex as potential biocontrol agents. Future work will continue to test the viability of these bacteria as biocontrol agents via experimental treatments with live captive bats. The failure of previous non-biocontrol methods highlights the importance of developing these bacteria as a biologically-friendly method for controlling Gd. A bat infected with Geomyces destructans. Photo by West Virginia Division of Natural Resources Bacterial culture from the swab of a bat's wings

Controlling enhanced absorption in graphene metamaterial

NASA Astrophysics Data System (ADS)

Zhou, Qihui; Liu, Peiguo; Bian, Li-an; Liu, Hanqing; Liu, Chenxi; Chen, Genghui

2018-04-01

In this paper, a controllable terahertz (THz) metamaterial absorber (MA) is designed with the circuit analog method. Taking advantage of the patterned graphene on SiO2/doped Si/polyimide substrates with a gold reflector, the controllable MA achieves perfect absorption at 0.75 THz. The chemical potential of graphene is regulated by controlling the voltage between graphene and doped Si layers. As the chemical potential varies from 0 eV to 0.5 eV, the MA is changed from reflection (<0.37) to absorption (>0.99). The distributions of surface current and electric field are illustrated to analyze the resonant characteristic of patterned graphene. According to the resonant characteristic, we introduce patterned graphene elements with different dimension in a unit cell, which effectively extends the effective absorption bandwidth (absorption > 0 . 9) from 0.67-0.93 THz to 0.52-0.95 THz. Moreover, replacing part of the graphene structure with gold, the switchable MA is turned into a frequency tunable MA. The absorption peak moves from 0.62 THz to 0.92 THz as the chemical potential increases from 0.1 eV to 0.5 eV. These designs overcome limitation of traditional absorbers and exhibit great potentials in many practical applications.

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.

Anti-tick biological control agents: assessment and future perspectives

USGS Publications Warehouse

Samish, M.; Ginsberg, H.S.; Glazer, I.; Bowman, Alan. S.; Nuttall, Patricia A.

2008-01-01

Widespread and increasing resistance to most available acaracides threatens both global livestock industries and public health. This necessitates better understanding of ticks and the diseases they transmit in the development of new control strategies. Ticks: Biology, Disease and Control is written by an international collection of experts and covers in-depth information on aspects of the biology of the ticks themselves, various veterinary and medical tick-borne pathogens, and aspects of traditional and potential new control methods. A valuable resource for graduate students, academic researchers and professionals, the book covers the whole gamut of ticks and tick-borne diseases from microsatellites to satellite imagery and from exploiting tick saliva for therapeutic drugs to developing drugs to control tick populations. It encompasses the variety of interconnected fields impinging on the economically important and biologically fascinating phenomenon of ticks, the diseases they transmit and methods of their control.

A support vector machine based control application to the experimental three-tank system.

PubMed

Iplikci, Serdar

2010-07-01

This paper presents a support vector machine (SVM) approach to generalized predictive control (GPC) of multiple-input multiple-output (MIMO) nonlinear systems. The possession of higher generalization potential and at the same time avoidance of getting stuck into the local minima have motivated us to employ SVM algorithms for modeling MIMO systems. Based on the SVM model, detailed and compact formulations for calculating predictions and gradient information, which are used in the computation of the optimal control action, are given in the paper. The proposed MIMO SVM-based GPC method has been verified on an experimental three-tank liquid level control system. Experimental results have shown that the proposed method can handle the control task successfully for different reference trajectories. Moreover, a detailed discussion on data gathering, model selection and effects of the control parameters have been given in this paper. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Spatial variation in mortality risk for haematological malignancies near a petrochemical refinery: a population-based case-control study

PubMed Central

Di Salvo, Francesca; Meneghini, Elisabetta; Vieira, Veronica; Baili, Paolo; Mariottini, Mauro; Baldini, Marco; Micheli, Andrea; Sant, Milena

2015-01-01

Introduction The study investigated the geographic variation of mortality risk for hematological malignancies (HMs) in order to identify potential high-risk areas near an Italian petrochemical refinery. Material and methods A population-based case-control study was conducted and residential histories for 171 cases and 338 sex- and age-matched controls were collected. Confounding factors were obtained from interviews with consenting relatives for 109 HM deaths and 267 controls. To produce risk mortality maps, two different approaches were applied. We mapped (1) adptive kernel density relative risk estimation (KDE) for case-control studies which estimates a spatial relative risk function using the ratio between cases and controls’ densities, and (2) estimated odds ratios for case-control study data using generalized additive models (GAMs) to smooth the effect of location, a proxy for exposure, while adjusting for confounding variables. Results No high-risk areas for HM mortality were identified among all subjects (men and women combined), by applying both approaches. Using the adaptive KDE approach, we found a significant increase in death risk only among women in a large area 2–6 km southeast of the refinery and the application of GAMs also identified a similarly-located significant high-risk area among women only (global p-value<0.025). Potential confounding risk factors we considered in the GAM did not alter the results. Conclusion Both approaches identified a high-risk area close to the refinery among women only. Those spatial methods are useful tools for public policy management to determine priority areas for intervention. Our findings suggest several directions for further research in order to identify other potential environmental exposures that may be assessed in forthcoming studies based on detailed exposure modeling. PMID:26073202

Process for control of cell division

NASA Technical Reports Server (NTRS)

Cone, C. D., Jr. (Inventor)

1977-01-01

A method of controlling mitosis of biological cells was developed, which involved inducing a change in the intracellular ionic hierarchy accompanying the cellular electrical transmembrane potential difference (Esubm) of the cells. The ionic hierarchy may be varied by imposing changes on the relative concentrations of Na(+), K(+) and Cl(-), or by directly imposing changes in the physical Esubm level across the cell surface.

Weight-Control Practices Reported by Students in a Maine Middle School

ERIC Educational Resources Information Center

Majka, Alan

2011-01-01

Extension professionals who work with youth are often faced with issues of body weight, diet and/or body image. How we handle these topics has the potential to either help or harm. The goal of the study reported here was to explore the prevalence and types of weight-control methods practiced by middle school students. The majority of students…

Hypnosis control based on the minimum concentration of anesthetic drug for maintaining appropriate hypnosis.

PubMed

Furutani, Eiko; Nishigaki, Yuki; Kanda, Chiaki; Takeda, Toshihiro; Shirakami, Gotaro

2013-01-01

This paper proposes a novel hypnosis control method using Auditory Evoked Potential Index (aepEX) as a hypnosis index. In order to avoid side effects of an anesthetic drug, it is desirable to reduce the amount of an anesthetic drug during surgery. For this purpose many studies of hypnosis control systems have been done. Most of them use Bispectral Index (BIS), another hypnosis index, but it has problems of dependence on anesthetic drugs and nonsmooth change near some particular values. On the other hand, aepEX has an ability of clear distinction between patient consciousness and unconsciousness and independence of anesthetic drugs. The control method proposed in this paper consists of two elements: estimating the minimum effect-site concentration for maintaining appropriate hypnosis and adjusting infusion rate of an anesthetic drug, propofol, using model predictive control. The minimum effect-site concentration is estimated utilizing the property of aepEX pharmacodynamics. The infusion rate of propofol is adjusted so that effect-site concentration of propofol may be kept near and always above the minimum effect-site concentration. Simulation results of hypnosis control using the proposed method show that the minimum concentration can be estimated appropriately and that the proposed control method can maintain hypnosis adequately and reduce the total infusion amount of propofol.

Potential of spark ignition engine for increased fuel efficiency. Final report, January-October 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, T. Jr.; Cole, D.; Bolt, J.A.

The objective of this study was to assess the potential of the spark ignition engine to deliver maximum fuel efficiency at 1981 Statutory Emission Standards in the 1983-1984 timeframe and beyond that to 1990. Based on the results of an extensive literature search, manufacturer's known product plans, and fuel economies of 1978 engines as a baseline, proposed methods of attaining fuel economy while complying with the future standards were ascertained. Methods of engine control optimization, engine design optimization as well as methods of varying engine parameters were considered. The potential improvements in fuel economy associated with these methods, singly andmore » in combination, were determined and are expressed as percentage changes of the fuel economy of the baseline engines. A summary of the principal conclusions are presented, followed by a description of the engine baseline reference, analysis and projection of fuel economy improvements, and a preliminary assessment of the impact of fuel economy benefits on manufacturing cost.« less

Evaluation of thrombolytic potential of three medicinal plants available in Bangladesh, as a potent source of thrombolytic compounds

PubMed Central

Ramjan, Ali; Hossain, Marjan; Runa, Jannatul Ferdous; Md, Hasanuzzaman; Mahmodul, Islam

2014-01-01

Objective: The present study is aimed to investigate in vitro thrombolytic activity of three Bangladeshi medicinal plants Averrhoa bilimbi (Oxalidiaceae), Clerodendrum viscosum (Verbanaceae) and Drynaria quercifolia (Polypodiaceae). Materials and methods: Each the plant was extracted with methanol at room temperature and the concentrated methanolic extracts (MEF) were fractionated by the modified Kupchan partitioning method to render pet-ether soluble fraction (PESF), carbon tetrachloride soluble fraction (CTSF), chloroform soluble fraction (CSF) and aqueous soluble fraction (AQSF). To observe their thrombolytic potential, a prompt and swift method was involved where streptokinase and water were used as positive and negative control, respectively. Result: Among the three plants, AQSF and PESF of D. quercifolia with CTSF of C. viscosum exhibited highest thrombolytic activity by clot lysis of 34.38%, 34.27% and 28.64%, respectively. Among other extracts A. bilimbi, C. viscosun and D.quercifolia showed significant percentage (%) of clot lysis compared to standard streptokinase (41.05%) while the negative control water revealed 3.31 % lysis of clot. Conclusion: From our findings it is observed that all the plants revealed remarkable thrombolytic activity. Therefore, steps should be taken to observe in vivo clot dissolving potential and to isolate active component(s) of these extracts. PMID:25386407

A Simple Method for Decreasing the Liquid Junction Potential in a Flow-through-Type Differential pH Sensor Probe Consisting of pH-FETs by Exerting Spatiotemporal Control of the Liquid Junction

PubMed Central

Yamada, Akira; Mohri, Satoshi; Nakamura, Michihiro; Naruse, Keiji

2015-01-01

The liquid junction potential (LJP), the phenomenon that occurs when two electrolyte solutions of different composition come into contact, prevents accurate measurements in potentiometry. The effect of the LJP is usually remarkable in measurements of diluted solutions with low buffering capacities or low ion concentrations. Our group has constructed a simple method to eliminate the LJP by exerting spatiotemporal control of a liquid junction (LJ) formed between two solutions, a sample solution and a baseline solution (BLS), in a flow-through-type differential pH sensor probe. The method was contrived based on microfluidics. The sensor probe is a differential measurement system composed of two ion-sensitive field-effect transistors (ISFETs) and one Ag/AgCl electrode. With our new method, the border region of the sample solution and BLS is vibrated in order to mix solutions and suppress the overshoot after the sample solution is suctioned into the sensor probe. Compared to the conventional method without vibration, our method shortened the settling time from over two min to 15 s and reduced the measurement error by 86% to within 0.060 pH. This new method will be useful for improving the response characteristics and decreasing the measurement error of many apparatuses that use LJs. PMID:25835300

Optimized multiparametric flow cytometric analysis of circulating endothelial cells and their subpopulations in peripheral blood of patients with solid tumors: a technical analysis.

PubMed

Zhou, Fangbin; Zhou, Yaying; Yang, Ming; Wen, Jinli; Dong, Jun; Tan, Wenyong

2018-01-01

Circulating endothelial cells (CECs) and their subpopulations could be potential novel biomarkers for various malignancies. However, reliable enumerable methods are warranted to further improve their clinical utility. This study aimed to optimize a flow cytometric method (FCM) assay for CECs and subpopulations in peripheral blood for patients with solid cancers. An FCM assay was used to detect and identify CECs. A panel of 60 blood samples, including 44 metastatic cancer patients and 16 healthy controls, were used in this study. Some key issues of CEC enumeration, including sample material and anticoagulant selection, optimal titration of antibodies, lysis/wash procedures of blood sample preparation, conditions of sample storage, sufficient cell events to enhance the signal, fluorescence-minus-one controls instead of isotype controls to reduce background noise, optimal selection of cell surface markers, and evaluating the reproducibility of our method, were integrated and investigated. Wilcoxon and Mann-Whitney U tests were used to determine statistically significant differences. In this validation study, we refined a five-color FCM method to detect CECs and their subpopulations in peripheral blood of patients with solid tumors. Several key technical issues regarding preanalytical elements, FCM data acquisition, and analysis were addressed. Furthermore, we clinically validated the utility of our method. The baseline levels of mature CECs, endothelial progenitor cells, and activated CECs were higher in cancer patients than healthy subjects ( P <0.01). However, there was no significant difference in resting CEC levels between healthy subjects and cancer patients ( P =0.193). We integrated and comprehensively addressed significant technical issues found in previously published assays and validated the reproducibility and sensitivity of our proposed method. Future work is required to explore the potential of our optimized method in clinical oncologic applications.

Evaluation of agricultural nonpoint source pollution potential risk over China with a Transformed-Agricultural Nonpoint Pollution Potential Index method.

PubMed

Yang, Fei; Xu, Zhencheng; Zhu, Yunqiang; He, Chansheng; Wu, Genyi; Qiu, Jin Rong; Fu, Qiang; Liu, Qingsong

2013-01-01

Agricultural nonpoint source (NPS) pollution has been the most important threat to water environment quality. Understanding the spatial distribution of NPS pollution potential risk is important for taking effective measures to control and reduce NPS pollution. A Transformed-Agricultural Nonpoint Pollution Potential Index (T-APPI) model was constructed for evaluating the national NPS pollution potential risk in this study; it was also combined with remote sensing and geographic information system techniques for evaluation on the large scale and at 1 km2 spatial resolution. This model considers many factors contributing to the NPS pollution as the original APPI model, summarized as four indicators of the runoff, sediment production, chemical use and the people and animal load. These four indicators were analysed in detail at 1 km2 spatial resolution throughout China. The T-APPI model distinguished the four indicators into pollution source factors and transport process factors; it also took their relationship into consideration. The studied results showed that T-APPI is a credible and convenient method for NPS pollution potential risk evaluation. The results also indicated that the highest NPS pollution potential risk is distributed in the middle-southern Jiangsu province. Several other regions, including the North China Plain, Chengdu Basin Plain, Jianghan Plain, cultivated lands in Guangdong and Guangxi provinces, also showed serious NPS pollution potential. This study can provide a scientific reference for predicting the future NPS pollution risk throughout China and may be helpful for taking reasonable and effective measures for preventing and controlling NPS pollution.

Electroosmotic flow and mixing in microchannels with the lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Tang, G. H.; Li, Zhuo; Wang, J. K.; He, Y. L.; Tao, W. Q.

2006-11-01

Understanding the electroosmotic flow in microchannels is of both fundamental and practical significance for the design and optimization of various microfluidic devices to control fluid motion. In this paper, a lattice Boltzmann equation, which recovers the nonlinear Poisson-Boltzmann equation, is used to solve the electric potential distribution in the electrolytes, and another lattice Boltzmann equation, which recovers the Navier-Stokes equation including the external force term, is used to solve the velocity fields. The method is validated by the electric potential distribution in the electrolytes and the pressure driven pulsating flow. Steady-state and pulsating electroosmotic flows in two-dimensional parallel uniform and nonuniform charged microchannels are studied with this lattice Boltzmann method. The simulation results show that the heterogeneous surface potential distribution and the electroosmotic pulsating flow can induce chaotic advection and thus enhance the mixing in microfluidic systems efficiently.

Method and apparatus for synthesizing HMX and N/sub 2/O/sub 5/. [Patent application; cyclotetramethylenetetraamine

DOEpatents

McGuire, R.R.; Coon, C.L.; Harrar, J.E.; Pearson, R.K.

1982-07-20

A method and apparatus for electrochemically synthesizing N/sub 2/O/sub 5/ includes oxidizing a solution of N/sub 2/O/sub 4//HNO/sub 3/ at an anode, while maintaining a controlled potential between the N/sub 2/O/sub 4//HNO/sub 3/ solution and the anode. A potential of about 1.35 to 2.0V vs. SCE is preferred, while a potential of about 1.80V vs. SCE is most preferred. Thereafter, the N/sub 2/O/sub 5/ is reacted with either 1.5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DADN) or 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane (TAT) to form cyclotetramethylenetetraamine (HMX).

Amoeba-related health risk in drinking water systems: could monitoring of amoebae be a complementary approach to current quality control strategies?

PubMed

Codony, Francesc; Pérez, Leonardo Martín; Adrados, Bárbara; Agustí, Gemma; Fittipaldi, Mariana; Morató, Jordi

2012-01-01

Culture-based methods for fecal indicator microorganisms are the standard protocol to assess potential health risk from drinking water systems. However, these traditional fecal indicators are inappropriate surrogates for disinfection-resistant fecal pathogens and the indigenous pathogens that grow in drinking water systems. There is now a range of molecular-based methods, such as quantitative PCR, which allow detection of a variety of pathogens and alternative indicators. Hence, in addition to targeting total Escherichia coli (i.e., dead and alive) for the detection of fecal pollution, various amoebae may be suitable to indicate the potential presence of pathogenic amoeba-resisting microorganisms, such as Legionellae. Therefore, monitoring amoeba levels by quantitative PCR could be a useful tool for directly and indirectly evaluating health risk and could also be a complementary approach to current microbial quality control strategies for drinking water systems.

Thiolated polymers as mucoadhesive drug delivery systems.

PubMed

Duggan, Sarah; Cummins, Wayne; O' Donovan, Orla; Hughes, Helen; Owens, Eleanor

2017-03-30

Mucoadhesion is the process of binding a material to the mucosal layer of the body. Utilising both natural and synthetic polymers, mucoadhesive drug delivery is a method of controlled drug release which allows for intimate contact between the polymer and a target tissue. It has the potential to increase bioavailability, decrease potential side effects and offer protection to more sensitive drugs such as proteins and peptide based drugs. The thiolation of polymers has, in the last number of years, come to the fore of mucoadhesive drug delivery, markedly improving mucoadhesion due to the introduction of free thiol groups onto the polymer backbone while also offering a more cohesive polymeric matrix for the slower and more controlled release of drug. This review explores the concept of mucoadhesion and the recent advances in both the polymers and the methods of thiolation used in the synthesis of mucoadhesive drug delivery devices. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural issues affecting mixed methods studies in health research: a qualitative study.

PubMed

O'Cathain, Alicia; Nicholl, Jon; Murphy, Elizabeth

2009-12-09

Health researchers undertake studies which combine qualitative and quantitative methods. Little attention has been paid to the structural issues affecting this mixed methods approach. We explored the facilitators and barriers to undertaking mixed methods studies in health research. Face-to-face semi-structured interviews with 20 researchers experienced in mixed methods research in health in the United Kingdom. Structural facilitators for undertaking mixed methods studies included a perception that funding bodies promoted this approach, and the multidisciplinary constituency of some university departments. Structural barriers to exploiting the potential of these studies included a lack of education and training in mixed methods research, and a lack of templates for reporting mixed methods articles in peer-reviewed journals. The 'hierarchy of evidence' relating to effectiveness studies in health care research, with the randomised controlled trial as the gold standard, appeared to pervade the health research infrastructure. Thus integration of data and findings from qualitative and quantitative components of mixed methods studies, and dissemination of integrated outputs, tended to occur through serendipity and effort, further highlighting the presence of structural constraints. Researchers are agents who may also support current structures - journal reviewers and editors, and directors of postgraduate training courses - and thus have the ability to improve the structural support for exploiting the potential of mixed methods research. The environment for health research in the UK appears to be conducive to mixed methods research but not to exploiting the potential of this approach. Structural change, as well as change in researcher behaviour, will be necessary if researchers are to fully exploit the potential of using mixed methods research.

Toward brain-computer interface based wheelchair control utilizing tactually-evoked event-related potentials

PubMed Central

2014-01-01

Background People with severe disabilities, e.g. due to neurodegenerative disease, depend on technology that allows for accurate wheelchair control. For those who cannot operate a wheelchair with a joystick, brain-computer interfaces (BCI) may offer a valuable option. Technology depending on visual or auditory input may not be feasible as these modalities are dedicated to processing of environmental stimuli (e.g. recognition of obstacles, ambient noise). Herein we thus validated the feasibility of a BCI based on tactually-evoked event-related potentials (ERP) for wheelchair control. Furthermore, we investigated use of a dynamic stopping method to improve speed of the tactile BCI system. Methods Positions of four tactile stimulators represented navigation directions (left thigh: move left; right thigh: move right; abdomen: move forward; lower neck: move backward) and N = 15 participants delivered navigation commands by focusing their attention on the desired tactile stimulus in an oddball-paradigm. Results Participants navigated a virtual wheelchair through a building and eleven participants successfully completed the task of reaching 4 checkpoints in the building. The virtual wheelchair was equipped with simulated shared-control sensors (collision avoidance), yet these sensors were rarely needed. Conclusion We conclude that most participants achieved tactile ERP-BCI control sufficient to reliably operate a wheelchair and dynamic stopping was of high value for tactile ERP classification. Finally, this paper discusses feasibility of tactile ERPs for BCI based wheelchair control. PMID:24428900

Controls on project proponents and environmental impact assessment effectiveness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortolano, L.

The degree of effectiveness of environmental impact assessment (EIA) for particular projects is associated with the existence of mechanisms of organizational control. Five dimensions of EIA effectiveness are considered: procedural compliance, completeness of EIA documents, methods to assess impacts, influence on project decisions, and weight given to environmental factors. Six mechanisms of control are introduced and illustrated by programs and projects in several countries. Experience in the Philippines under President Marcos demonstrates that procedural control in the form of EIA regulations, when used without other control mechanisms, will lead at most to token compliance. Judicial control, as practiced in themore » US, yields high procedural compliance. Evaluative control can yield effective EIA, but some systems based on this form of control treat only a small fraction of the major projects proposed. Both control exerted by development assistance organizations and control by professionals have great potential for yielding effective EIA, but that potential has not been fully realized. Control exerted directly by citizens or agencies not otherwise involved in EIA is uncommon, but cases from Taiwan demonstrate that those controls can be significant. An understanding of relationships between control mechanisms and EIA effectiveness is useful in designing EIA policies and programs.« less

Comparison of a brain-based adaptive system and a manual adaptable system for invoking automation.

PubMed

Bailey, Nathan R; Scerbo, Mark W; Freeman, Frederick G; Mikulka, Peter J; Scott, Lorissa A

2006-01-01

Two experiments are presented examining adaptive and adaptable methods for invoking automation. Empirical investigations of adaptive automation have focused on methods used to invoke automation or on automation-related performance implications. However, no research has addressed whether performance benefits associated with brain-based systems exceed those in which users have control over task allocations. Participants performed monitoring and resource management tasks as well as a tracking task that shifted between automatic and manual modes. In the first experiment, participants worked with an adaptive system that used their electroencephalographic signals to switch the tracking task between automatic and manual modes. Participants were also divided between high- and low-reliability conditions for the system-monitoring task as well as high- and low-complacency potential. For the second experiment, participants operated an adaptable system that gave them manual control over task allocations. Results indicated increased situation awareness (SA) of gauge instrument settings for individuals high in complacency potential using the adaptive system. In addition, participants who had control over automation performed more poorly on the resource management task and reported higher levels of workload. A comparison between systems also revealed enhanced SA of gauge instrument settings and decreased workload in the adaptive condition. The present results suggest that brain-based adaptive automation systems may enhance perceptual level SA while reducing mental workload relative to systems requiring user-initiated control. Potential applications include automated systems for which operator monitoring performance and high-workload conditions are of concern.

Likelihood-based methods for evaluating principal surrogacy in augmented vaccine trials.

PubMed

Liu, Wei; Zhang, Bo; Zhang, Hui; Zhang, Zhiwei

2017-04-01

There is growing interest in assessing immune biomarkers, which are quick to measure and potentially predictive of long-term efficacy, as surrogate endpoints in randomized, placebo-controlled vaccine trials. This can be done under a principal stratification approach, with principal strata defined using a subject's potential immune responses to vaccine and placebo (the latter may be assumed to be zero). In this context, principal surrogacy refers to the extent to which vaccine efficacy varies across principal strata. Because a placebo recipient's potential immune response to vaccine is unobserved in a standard vaccine trial, augmented vaccine trials have been proposed to produce the information needed to evaluate principal surrogacy. This article reviews existing methods based on an estimated likelihood and a pseudo-score (PS) and proposes two new methods based on a semiparametric likelihood (SL) and a pseudo-likelihood (PL), for analyzing augmented vaccine trials. Unlike the PS method, the SL method does not require a model for missingness, which can be advantageous when immune response data are missing by happenstance. The SL method is shown to be asymptotically efficient, and it performs similarly to the PS and PL methods in simulation experiments. The PL method appears to have a computational advantage over the PS and SL methods.

Enhanced factoring with a bose-einstein condensate.

PubMed

Sadgrove, Mark; Kumar, Sanjay; Nakagawa, Ken'ichi

2008-10-31

We present a novel method to realize analog sum computation with a Bose-Einstein condensate in an optical lattice potential subject to controlled phase jumps. We use the method to implement the Gauss sum algorithm for factoring numbers. By exploiting higher order quantum momentum states, we are able to improve the algorithm's accuracy beyond the limits of the usual classical implementation.

Comparing Impact Findings from Design-Based and Model-Based Methods: An Empirical Investigation. NCEE 2017-4026

ERIC Educational Resources Information Center

Kautz, Tim; Schochet, Peter Z.; Tilley, Charles

2017-01-01

A new design-based theory has recently been developed to estimate impacts for randomized controlled trials (RCTs) and basic quasi-experimental designs (QEDs) for a wide range of designs used in social policy research (Imbens & Rubin, 2015; Schochet, 2016). These methods use the potential outcomes framework and known features of study designs…

Generation of large coherent states by bang–bang control of a trapped-ion oscillator

PubMed Central

Alonso, J.; Leupold, F. M.; Solèr, Z. U.; Fadel, M.; Marinelli, M.; Keitch, B. C.; Negnevitsky, V.; Home, J. P.

2016-01-01

Fast control of quantum systems is essential to make use of quantum properties before they degrade by decoherence. This is important for quantum-enhanced information processing, as well as for pushing quantum systems towards the boundary between quantum and classical physics. ‘Bang–bang' control attains the ultimate speed limit by making large changes to control fields much faster than the system can respond, but is often challenging to implement experimentally. Here we demonstrate bang–bang control of a trapped-ion oscillator using nanosecond switching of the trapping potentials. We perform controlled displacements with which we realize coherent states with up to 10,000 quanta of energy. We use these displaced states to verify the form of the ion-light interaction at high excitations far outside the usual regime of operation. These methods provide new possibilities for quantum-state manipulation and generation, alongside the potential for a significant increase in operational clock speed for trapped-ion quantum information processing. PMID:27046513

Fabrication of corneal epithelial cell sheets maintaining colony-forming cells without feeder cells by oxygen-controlled method.

PubMed

Nakajima, Ryota; Takeda, Shizu

2014-01-01

The use of murine 3T3 feeder cells needs to be avoided when fabricating corneal epithelial cell sheets for use in treating ocular surface diseases. However, the expression level of the epithelial stem/progenitor cell marker, p63, is down-regulated in feeder-free culture systems. In this study, in order to fabricate corneal epithelial cell sheets that maintain colony-forming cells without using any feeder cells, we investigated the use of an oxygen-controlled method that was developed previously to fabricate cell sheets efficiently. Rabbit limbal epithelial cells were cultured under hypoxia (1-10% O2) and under normoxia during stratification after reaching confluence. Multilayered corneal epithelial cell sheets were fabricated using an oxygen-controlled method, and immunofluorescence analysis showed that cytokeratin 3 and p63 was expressed in appropriate localization in the cell sheets. The colony-forming efficiency of the cell sheets fabricated by the oxygen-controlled method without feeder cells was significantly higher than that of cell sheets fabricated under 20% O2 without feeder cells. These results indicate that the oxygen-controlled method has the potential to achieve a feeder-free culture system for fabricating corneal epithelial cell sheets for corneal regeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Self-assembly and hierarchical patterning of aligned organic nanowire arrays by solvent evaporation on substrates with patterned wettability.

PubMed

Bao, Rong-Rong; Zhang, Cheng-Yi; Zhang, Xiu-Juan; Ou, Xue-Mei; Lee, Chun-Sing; Jie, Jian-Sheng; Zhang, Xiao-Hong

2013-06-26

The controlled growth and alignment of one-dimensional organic nanostructures at well-defined locations considerably hinders the integration of nanostructures for electronic and optoelectronic applications. Here, we demonstrate a simple process to achieve the growth, alignment, and hierarchical patterning of organic nanowires on substrates with controlled patterns of surface wettability. The first-level pattern is confined by the substrate patterns of wettability. Organic nanostructures are preferentially grown on solvent wettable regions. The second-level pattern is the patterning of aligned organic nanowires deposited by controlling the shape and movement of the solution contact lines during evaporation on the wettable regions. This process is controlled by the cover-hat-controlled method or vertical evaportation method. Therefore, various new patterns of organic nanostructures can be obtained by combing these two levels of patterns. This simple method proves to be a general approach that can be applied to other organic nanostructure systems. Using the as-prepared patterned nanowire arrays, an optoelectronic device (photodetector) is easily fabricated. Hence, the proposed simple, large-scale, low-cost method of preparing patterns of highly ordered organic nanostructures has high potential applications in various electronic and optoelectronic devices.

Biofouling of Water Treatment Membranes: A Review of the Underlying Causes, Monitoring Techniques and Control Measures

PubMed Central

Nguyen, Thang; Roddick, Felicity A.; Fan, Linhua

2012-01-01

Biofouling is a critical issue in membrane water and wastewater treatment as it greatly compromises the efficiency of the treatment processes. It is difficult to control, and significant economic resources have been dedicated to the development of effective biofouling monitoring and control strategies. This paper highlights the underlying causes of membrane biofouling and provides a review on recent developments of potential monitoring and control methods in water and wastewater treatment with the aim of identifying the remaining issues and challenges in this area. PMID:24958430

Development and Evaluation of a Combined Cultivator and Band Sprayer with a Row-Centering RTK-GPS Guidance System

PubMed Central

Perez-Ruiz, Manuel; Carballido, Jacob; Agüera, Juan; Rodríguez-Lizana, Antonio

2013-01-01

Typically, low-pressure sprayers are used to uniformly apply pre- and post-emergent herbicides to control weeds in crop rows. An innovative machine for weed control in inter-row and intra-row areas, with a unique combination of inter-row cultivation tooling and intra-row band spraying for six rows and an electro-hydraulic side-shift frame controlled by a GPS system, was developed and evaluated. Two weed management strategies were tested in the field trials: broadcast spraying (the conventional method) and band spraying with mechanical weed control using RTK-GPS (the experimental method). This approach enabled the comparison between treatments from the perspective of cost savings and efficacy in weed control for a sugar beet crop. During the 2010–2011 season, the herbicide application rate (112 L ha−1) of the experimental method was approximately 50% of the conventional method, and thus a significant reduction in the operating costs of weed management was achieved. A comparison of the 0.2-trimmed means of weed population post-treatment showed that the treatments achieved similar weed control rates at each weed survey date. Sugar beet yields were similar with both methods (p = 0.92). The use of the experimental equipment is cost-effective on ≥20 ha of crops. These initial results show good potential for reducing herbicide application in the Spanish beet industry. PMID:23478600

Development and evaluation of a combined cultivator and band sprayer with a row-centering RTK-GPS guidance system.

PubMed

Perez-Ruiz, Manuel; Carballido, Jacob; Agüera, Juan; Rodríguez-Lizana, Antonio

2013-03-11

Typically, low-pressure sprayers are used to uniformly apply pre- and post-emergent herbicides to control weeds in crop rows. An innovative machine for weed control in inter-row and intra-row areas, with a unique combination of inter-row cultivation tooling and intra-row band spraying for six rows and an electro-hydraulic side-shift frame controlled by a GPS system, was developed and evaluated. Two weed management strategies were tested in the field trials: broadcast spraying (the conventional method) and band spraying with mechanical weed control using RTK-GPS (the experimental method). This approach enabled the comparison between treatments from the perspective of cost savings and efficacy in weed control for a sugar beet crop. During the 2010-2011 season, the herbicide application rate (112 L ha(-1)) of the experimental method was approximately 50% of the conventional method, and thus a significant reduction in the operating costs of weed management was achieved. A comparison of the 0.2-trimmed means of weed population post-treatment showed that the treatments achieved similar weed control rates at each weed survey date. Sugar beet yields were similar with both methods (p = 0.92). The use of the experimental equipment is cost-effective on ≥20 ha of crops. These initial results show good potential for reducing herbicide application in the Spanish beet industry.

Method and automated apparatus for detecting coliform organisms

NASA Technical Reports Server (NTRS)

Dill, W. P.; Taylor, R. E.; Jeffers, E. L. (Inventor)

1980-01-01

Method and automated apparatus are disclosed for determining the time of detection of metabolically produced hydrogen by coliform bacteria cultured in an electroanalytical cell from the time the cell is inoculated with the bacteria. The detection time data provides bacteria concentration values. The apparatus is sequenced and controlled by a digital computer to discharge a spent sample, clean and sterilize the culture cell, provide a bacteria nutrient into the cell, control the temperature of the nutrient, inoculate the nutrient with a bacteria sample, measures the electrical potential difference produced by the cell, and measures the time of detection from inoculation.

The ecology of microorganisms in a small closed system: Potential benefits and problems for space station

NASA Technical Reports Server (NTRS)

Rodgers, E. B.

1986-01-01

The inevitble presence on the space station of microorganisms associated with crew members and their environment will have the potential for both benefits and a range of problems including illness and corrosion of materials. This report reviews the literature presenting information about microorganisms pertinent to Environmental Control and Life Support (ECLS) on the space station. The perspective of the report is ecological, viewing the space station as an ecosystem in which biological relationships are affected by factors such as zero gravity and by closure of a small volume of space. Potential sites and activities of microorganisms on the space station and their environmental limits, microbial standards for the space station, monitoring and control methods, effects of space factors on microorganisms, and extraterrestrial contamination are discussed.

Quantum confinement of exciton-polaritons in a structured (Al,Ga)As microcavity

NASA Astrophysics Data System (ADS)

Kuznetsov, Alexander S.; Helgers, Paul L. J.; Biermann, Klaus; Santos, Paulo V.

2018-05-01

The realization of quantum functionalities with polaritons in an all-semiconductor platform requires the control of the energy and spatial overlap of the wave functions of single polaritons trapped in potentials with precisely controlled shape and size. In this study we reach the confinement of microcavity polaritons in traps with an effective potential width down to 1 µm, produced by patterning the active region of the (Al,Ga)As microcavity between two molecular beam epitaxy growth runs. We correlate spectroscopic and structural data to show that the smooth surface relief of the patterned traps translates into a graded confinement potential characterized by lateral interfaces with a finite lateral width. We show that the structuring method is suitable for the fabrication of arrays of proximal traps, supporting hybridization between adjacent lattice sites.

Encouraging stormwater management using a reverse auction: potential to restore stream ecosystems

EPA Science Inventory

Stormwater runoff is the primary mechanism by which urbanizing landscapes disrupt natural, stream ecosystems. Source control management has been demonstrated as an effective and cost-efficient method for reducing stormwater runoff; however, sufficiently widespread implementation...

Is Wildlife Fertility Control Always Humane?

PubMed Central

Hampton, Jordan O.; Hyndman, Timothy H.; Barnes, Anne; Collins, Teresa

2015-01-01

Simple Summary There are various fertility control methods (modalities) currently available that aim to reduce the abundance of problematic free-ranging mammalian wildlife. Here, we propose that dissimilarities in the mechanism of action indicate these methods produce great variation in animal welfare outcomes. We present a framework to assist managers in minimising animal welfare risks. Abstract Investigation of fertility control techniques to reduce reproductive rates in wildlife populations has been the source of much research. Techniques targeting wildlife fertility have been diverse. Most research into fertility control methods has focused upon efficacy, with few studies rigorously assessing animal welfare beyond opportunistic anecdote. However, fertility control techniques represent several very different mechanisms of action (modalities), each with their own different animal welfare risks. We provide a review of the mechanisms of action for fertility control methods, and consider the role of manipulation of reproductive hormones (“endocrine suppression”) for the long-term ability of animals to behave normally. We consider the potential welfare costs of animal manipulation techniques that are required to administer fertility treatments, including capture, restraint, surgery and drug delivery, and the requirement for repeated administration within the lifetime of an animal. We challenge the assumption that fertility control modalities generate similar and desirable animal welfare outcomes, and we argue that knowledge of reproductive physiology and behaviour should be more adeptly applied to wild animal management decisions. We encourage wildlife managers to carefully assess long-term behavioural risks, associated animal handling techniques, and the importance of positive welfare states when selecting fertility control methods as a means of population control. PMID:26506395

Recent advances in micro-vibration isolation

NASA Astrophysics Data System (ADS)

Liu, Chunchuan; Jing, Xingjian; Daley, Steve; Li, Fengming

2015-05-01

Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the aerospace environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.

Green Jobs: Definition and Method of Appraisal of Chemical and Biological Risks.

PubMed

Cheneval, Erwan; Busque, Marc-Antoine; Ostiguy, Claude; Lavoie, Jacques; Bourbonnais, Robert; Labrèche, France; Bakhiyi, Bouchra; Zayed, Joseph

2016-04-01

In the wake of sustainable development, green jobs are developing rapidly, changing the work environment. However a green job is not automatically a safe job. The aim of the study was to define green jobs, and to establish a preliminary risk assessment of chemical substances and biological agents for workers in Quebec. An operational definition was developed, along with criteria and sustainable development principles to discriminate green jobs from regular jobs. The potential toxicity or hazard associated with their chemical and biological exposures was assessed, and the workers' exposure appraised using an expert assessment method. A control banding approach was then used to assess risks for workers in selected green jobs. A double entry model allowed us to set priorities in terms of chemical or biological risk. Among jobs that present the highest risk potential, several are related to waste management. The developed method is flexible and could be adapted to better appraise the risks that workers are facing or to propose control measures. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

First Experiences Of ISFOC In The Maintenance Of CPV Plants

NASA Astrophysics Data System (ADS)

Sánchez, D.; Martínez, M.; Gil, E.; Rubio, F.; Pachón, J. L.; Banda, P.

2010-10-01

ISFOC CPV Plants are now working in normal operation, so ISFOC is beginning with the Maintenance. Like a first approximation, we have analyzed the incidences in the Energy generation. This analysis results that the tracker is the most vulnerable element of the installation, what it is reasonable, because it is the only mechanical element. In this business, the corrective actions for the Maintenance are very expensive; therefore it is mandatory to define a good policy for the Preventive Maintenance. With this idea, ISFOC is implementing Industrial tools (SCP) to control the Energy generation in order to maintain the Plants operating at its full potential. In this paper, we present the approach we are making to adapt the method to measure the energy generated by the concentrators and how the control charts can be used to organize the Preventive Maintenance actions. Finally, the first results are presented, where we show the potential of this method to organize the Maintenance at the same time we have initial calculations for the availability of the plants obtained with this method.

Dynamic thresholds and a summary ROC curve: Assessing prognostic accuracy of longitudinal markers.

PubMed

Saha-Chaudhuri, P; Heagerty, P J

2018-04-19

Cancer patients, chronic kidney disease patients, and subjects infected with HIV are routinely monitored over time using biomarkers that represent key health status indicators. Furthermore, biomarkers are frequently used to guide initiation of new treatments or to inform changes in intervention strategies. Since key medical decisions can be made on the basis of a longitudinal biomarker, it is important to evaluate the potential accuracy associated with longitudinal monitoring. To characterize the overall accuracy of a time-dependent marker, we introduce a summary ROC curve that displays the overall sensitivity associated with a time-dependent threshold that controls time-varying specificity. The proposed statistical methods are similar to concepts considered in disease screening, yet our methods are novel in choosing a potentially time-dependent threshold to define a positive test, and our methods allow time-specific control of the false-positive rate. The proposed summary ROC curve is a natural averaging of time-dependent incident/dynamic ROC curves and therefore provides a single summary of net error rates that can be achieved in the longitudinal setting. Copyright © 2018 John Wiley & Sons, Ltd.

Assessment of Quadrivalent Human Papillomavirus Vaccine Safety Using the Self-Controlled Tree-Temporal Scan Statistic Signal-Detection Method in the Sentinel System.

PubMed

Yih, W Katherine; Maro, Judith C; Nguyen, Michael; Baker, Meghan A; Balsbaugh, Carolyn; Cole, David V; Dashevsky, Inna; Mba-Jonas, Adamma; Kulldorff, Martin

2018-06-01

The self-controlled tree-temporal scan statistic-a new signal-detection method-can evaluate whether any of a wide variety of health outcomes are temporally associated with receipt of a specific vaccine, while adjusting for multiple testing. Neither health outcomes nor postvaccination potential periods of increased risk need be prespecified. Using US medical claims data in the Food and Drug Administration's Sentinel system, we employed the method to evaluate adverse events occurring after receipt of quadrivalent human papillomavirus vaccine (4vHPV). Incident outcomes recorded in emergency department or inpatient settings within 56 days after first doses of 4vHPV received by 9- through 26.9-year-olds in 2006-2014 were identified using International Classification of Diseases, Ninth Revision, diagnosis codes and analyzed by pairing the new method with a standard hierarchical classification of diagnoses. On scanning diagnoses of 1.9 million 4vHPV recipients, 2 statistically significant categories of adverse events were found: cellulitis on days 2-3 after vaccination and "other complications of surgical and medical procedures" on days 1-3 after vaccination. Cellulitis is a known adverse event. Clinically informed investigation of electronic claims records of the patients with "other complications" did not suggest any previously unknown vaccine safety problem. Considering that thousands of potential short-term adverse events and hundreds of potential risk intervals were evaluated, these findings add significantly to the growing safety record of 4vHPV.

Quantification of Sesquiterpene Lactones in Asteraceae Plant Extracts: Evaluation of their Allergenic Potential

PubMed Central

Salapovic, Helena; Geier, Johannes; Reznicek, Gottfried

2013-01-01

Sesquiterpene lactones (SLs), mainly those with an activated exocyclic methylene group, are important allergens in Asteraceae (Compositae) plants. As a screening tool, the Compositae mix, consisting of five Asteraceae plant extracts with allergenic potential (feverfew, tansy, arnica, yarrow, and German chamomile) is part of several national patch test baseline series. However, the SL content of the Compositae mix may vary due to the source material. Therefore, a simple spectrophotometric method for the quantitative measurement of SLs with the α-methylene-γ-butyrolactone moiety was developed, giving the percentage of allergenic compounds in plant extracts. The method has been validated and five Asteraceae extracts, namely feverfew (Tanacetum parthenium L.), tansy (Tanacetum vulgare L.), arnica (Arnica montana L.), yarrow (Achillea millefolium L.), and German chamomile (Chamomilla recutita L. Rauschert) that have been used in routine patch test screening were evaluated. A good correlation could be found between the results obtained using the proposed spectrophotometric method and the corresponding clinical results. Thus, the introduced method is a valuable tool for evaluating the allergenic potential and for the simple and efficient quality control of plant extracts with allergenic potential. PMID:24106675

Coherent Control About a Conical Intersection

NASA Astrophysics Data System (ADS)

Liekhus-Schmaltz, Chelsea; McCracken, Gregory; Kaldun, Andreas; Cryan, James P.; Bucksbaum, Philip H.

2017-04-01

Conical intersections (CIs) are degeneracies between molecular potential energy surfaces that occur in essentially all molecules with more than three atoms. Many studies have established that CIs allow for non-Born-Oppenheimer (non-adiabatic) molecular dynamics. In addition, CIs have many useful attributes for coherent control that have not been fully studied. Here we demonstrate two modes of control around a CI that make use of these properties. The first method uses a continuous light field, resonant absorption, and stimulated emission to control the population on two intersecting electronic states. The second method uses a pulsed light field and the geometric phase accumulated by a wavepacket traversing a CI to control the shape of the wavepacket. This work was supported by the National Science Foundation under Grant No. PHY-0649578, the DOE SCGSR fellowship program, and the DOE, Office of Science, BES, Chemical Sciences, Geosciences, and Biosciences Division.

Using spacecraft trace contaminant control systems to cure sick building syndrome

NASA Technical Reports Server (NTRS)

Graf, John C.

1994-01-01

Many residential and commercial buildings with centralized, recirculating, heating ventilation and air conditioning systems suffer from 'Sick Building Syndrome.' Ventilation rates are reduced to save energy costs, synthetic building materials off-gas contaminants, and unsafe levels of volatile organic compounds (VOC's) accumulate. These unsafe levels of contaminants can cause irritation of eyes and throat, fatigue and dizziness to building occupants. Increased ventilation, the primary method of treating Sick Building Syndrome is expensive (due to increased energy costs) and recently, the effectiveness of increased ventilation has been questioned. On spacecraft venting is not allowed, so the primary methods of air quality control are; source control, active filtering, and destruction of VOC's. Four non-venting contaminant removal technologies; strict material selection to provide source control, ambient temperature catalytic oxidation, photocatalytic oxidation, and uptake by higher plants, may have potential application for indoor air quality control.

Constrained dynamics approach for motion synchronization and consensus

NASA Astrophysics Data System (ADS)

Bhatia, Divya

In this research we propose to develop constrained dynamical systems based stable attitude synchronization, consensus and tracking (SCT) control laws for the formation of rigid bodies. The generalized constrained dynamics Equations of Motion (EOM) are developed utilizing constraint potential energy functions that enforce communication constraints. Euler-Lagrange equations are employed to develop the non-linear constrained dynamics of multiple vehicle systems. The constraint potential energy is synthesized based on a graph theoretic formulation of the vehicle-vehicle communication. Constraint stabilization is achieved via Baumgarte's method. The performance of these constrained dynamics based formations is evaluated for bounded control authority. The above method has been applied to various cases and the results have been obtained using MATLAB simulations showing stability, synchronization, consensus and tracking of formations. The first case corresponds to an N-pendulum formation without external disturbances, in which the springs and the dampers connected between the pendulums act as the communication constraints. The damper helps in stabilizing the system by damping the motion whereas the spring acts as a communication link relaying relative position information between two connected pendulums. Lyapunov stabilization (energy based stabilization) technique is employed to depict the attitude stabilization and boundedness. Various scenarios involving different values of springs and dampers are simulated and studied. Motivated by the first case study, we study the formation of N 2-link robotic manipulators. The governing EOM for this system is derived using Euler-Lagrange equations. A generalized set of communication constraints are developed for this system using graph theory. The constraints are stabilized using Baumgarte's techniques. The attitude SCT is established for this system and the results are shown for the special case of three 2-link robotic manipulators. These methods are then applied to the formation of N-spacecraft. Modified Rodrigues Parameters (MRP) are used for attitude representation of the spacecraft because of their advantage of being a minimum parameter representation. Constrained non-linear equations of motion for this system are developed and stabilized using a Proportional-Derivative (PD) controller derived based on Baumgarte's method. A system of 3 spacecraft is simulated and the results for SCT are shown and analyzed. Another problem studied in this research is that of maintaining SCT under unknown external disturbances. We use an adaptive control algorithm to derive control laws for the actuator torques and develop an estimation law for the unknown disturbance parameters to achieve SCT. The estimate of the disturbance is added as a feed forward term in the actual control law to obtain the stabilization of a 3-spacecraft formation. The disturbance estimates are generated via a Lyapunov analysis of the closed loop system. In summary, the constrained dynamics method shows a lot of potential in formation control, achieving stabilization, synchronization, consensus and tracking of a set of dynamical systems.

Preparation of ultrasmall porous carbon nanospheres by reverse microemulsion-hydrothermal method

NASA Astrophysics Data System (ADS)

Wang, Jiasheng; Zhao, Yahong; Wang, Wan-Hui; Bao, Ming

Porous carbon nanospheres (CNSs) have wide applications. A big challenge in materials science is synthesis of discrete ultrasmall porous carbon nanospheres. Herein, we report a facile reverse microemulsion-hydrothermal method to prepare discrete porous CNSs. The obtained CNSs possess an average diameter of 20nm and pores of 0.7nm and 3.4nm. Our work has provided a convenient method for the controllable synthesis of ultrasmall porous CNSs with potential applications.

Controlling ferromagnetism of (In,Fe)As semiconductors by electron doping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dang Vu, Nguyen; Fukushima, Tetsuya; Katayama-Yoshida, Hiroshi

2014-02-21

Based on experimental results, using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method and Monte Carlo simulation, we study the mechanism of ferromagnetic behavior of (In,Fe)As. We show that with doped Be atoms occupying in interstitial sites, chemical pair interactions between atoms and magnetic exchange interactions between Fe atoms change due to electron concentration. Therefore, by controlling the doping process, magnetic behavior of (In,Fe)As is controlled and ferromagnetism is observed in this semiconductor.

The control of flexible structure vibrations using a cantilevered adaptive truss

NASA Technical Reports Server (NTRS)

Wynn, Robert H., Jr.; Robertshaw, Harry H.

1991-01-01

Analytical and experimental procedures and design tools are presented for the control of flexible structure vibrations using a cantilevered adaptive truss. Simulated and experimental data are examined for three types of structures: a slender beam, a single curved beam, and two curved beams. The adaptive truss is shown to produce a 6,000-percent increase in damping, demonstrating its potential in vibration control. Good agreement is obtained between the simulated and experimental data, thus validating the modeling methods.

Zeta potential in oil-water-carbonate systems and its impact on oil recovery during controlled salinity water-flooding

PubMed Central

Jackson, Matthew D.; Al-Mahrouqi, Dawoud; Vinogradov, Jan

2016-01-01

Laboratory experiments and field trials have shown that oil recovery from carbonate reservoirs can be increased by modifying the brine composition injected during recovery in a process termed controlled salinity water-flooding (CSW). However, CSW remains poorly understood and there is no method to predict the optimum CSW composition. This work demonstrates for the first time that improved oil recovery (IOR) during CSW is strongly correlated to changes in zeta potential at both the mineral-water and oil-water interfaces. We report experiments in which IOR during CSW occurs only when the change in brine composition induces a repulsive electrostatic force between the oil-brine and mineral-brine interfaces. The polarity of the zeta potential at both interfaces must be determined when designing the optimum CSW composition. A new experimental method is presented that allows this. Results also show for the first time that the zeta potential at the oil-water interface may be positive at conditions relevant to carbonate reservoirs. A key challenge for any model of CSW is to explain why IOR is not always observed. Here we suggest that failures using the conventional (dilution) approach to CSW may have been caused by a positively charged oil-water interface that had not been identified. PMID:27876833

Hazard Identification and Risk Assessment in Water Treatment Plant considering Environmental Health and Safety Practice

NASA Astrophysics Data System (ADS)

Falakh, Fajrul; Setiani, Onny

2018-02-01

Water Treatment Plant (WTP) is an important infrastructure to ensure human health and the environment. In its development, aspects of environmental safety and health are of concern. This paper case study was conducted at the Water Treatment Plant Company in Semarang, Central Java, Indonesia. Hazard identification and risk assessment is one part of the occupational safety and health program at the risk management stage. The purpose of this study was to identify potential hazards using hazard identification methods and risk assessment methods. Risk assessment is done using criteria of severity and probability of accident. The results obtained from this risk assessment are 22 potential hazards present in the water purification process. Extreme categories that exist in the risk assessment are leakage of chlorine and industrial fires. Chlorine and fire leakage gets the highest value because its impact threatens many things, such as industrial disasters that could endanger human life and the environment. Control measures undertaken to avoid potential hazards are to apply the use of personal protective equipment, but management will also be better managed in accordance with hazard control hazards, occupational safety and health programs such as issuing work permits, emergency response training is required, Very useful in overcoming potential hazards that have been determined.

Structural issues affecting mixed methods studies in health research: a qualitative study

PubMed Central

2009-01-01

Background Health researchers undertake studies which combine qualitative and quantitative methods. Little attention has been paid to the structural issues affecting this mixed methods approach. We explored the facilitators and barriers to undertaking mixed methods studies in health research. Methods Face-to-face semi-structured interviews with 20 researchers experienced in mixed methods research in health in the United Kingdom. Results Structural facilitators for undertaking mixed methods studies included a perception that funding bodies promoted this approach, and the multidisciplinary constituency of some university departments. Structural barriers to exploiting the potential of these studies included a lack of education and training in mixed methods research, and a lack of templates for reporting mixed methods articles in peer-reviewed journals. The 'hierarchy of evidence' relating to effectiveness studies in health care research, with the randomised controlled trial as the gold standard, appeared to pervade the health research infrastructure. Thus integration of data and findings from qualitative and quantitative components of mixed methods studies, and dissemination of integrated outputs, tended to occur through serendipity and effort, further highlighting the presence of structural constraints. Researchers are agents who may also support current structures - journal reviewers and editors, and directors of postgraduate training courses - and thus have the ability to improve the structural support for exploiting the potential of mixed methods research. Conclusion The environment for health research in the UK appears to be conducive to mixed methods research but not to exploiting the potential of this approach. Structural change, as well as change in researcher behaviour, will be necessary if researchers are to fully exploit the potential of using mixed methods research. PMID:20003210

Innovative neurophysiological methods in itch research: long-latency evoked potentials after electrical and thermal stimulation in patients with atopic dermatitis.

PubMed

Yudina, Marina M; Toropina, Galina G; Lvov, Andrey; Gieler, Uwe

2011-10-01

The aim of this study was to examine the findings of innovative neurophysiological methods of itch research. Short-latency and pain-related somatosensory-evoked potentials after electrical stimulation, as well as long-latency evoked potentials after thermal stimulation were studied in 38 patients with atopic dermatitis (AD) and 26 healthy volunteers. Quantitative Sensory Testing of thermal perception was performed in 22 patients with AD from the main AD group and in 15 healthy volunteers. Brain hyperactivity to electrical stimuli, delayed thermal-evoked potentials and elevated thermal thresholds were revealed in patients with AD compared with healthy controls. The data indicate small nerve fibre dysfunction in patients with AD, which may contribute to the pathogenesis of AD and chronic itch. The study demonstrates objective approaches to assess the function of small nerve fibres in patients with chronic itch.

Kalman filter control of a model of spatiotemporal cortical dynamics

PubMed Central

Schiff, Steven J; Sauer, Tim

2007-01-01

Recent advances in Kalman filtering to estimate system state and parameters in nonlinear systems have offered the potential to apply such approaches to spatiotemporal nonlinear systems. We here adapt the nonlinear method of unscented Kalman filtering to observe the state and estimate parameters in a computational spatiotemporal excitable system that serves as a model for cerebral cortex. We demonstrate the ability to track spiral wave dynamics, and to use an observer system to calculate control signals delivered through applied electrical fields. We demonstrate how this strategy can control the frequency of such a system, or quench the wave patterns, while minimizing the energy required for such results. These findings are readily testable in experimental applications, and have the potential to be applied to the treatment of human disease. PMID:18310806

Mass univariate analysis of event-related brain potentials/fields I: a critical tutorial review.

PubMed

Groppe, David M; Urbach, Thomas P; Kutas, Marta

2011-12-01

Event-related potentials (ERPs) and magnetic fields (ERFs) are typically analyzed via ANOVAs on mean activity in a priori windows. Advances in computing power and statistics have produced an alternative, mass univariate analyses consisting of thousands of statistical tests and powerful corrections for multiple comparisons. Such analyses are most useful when one has little a priori knowledge of effect locations or latencies, and for delineating effect boundaries. Mass univariate analyses complement and, at times, obviate traditional analyses. Here we review this approach as applied to ERP/ERF data and four methods for multiple comparison correction: strong control of the familywise error rate (FWER) via permutation tests, weak control of FWER via cluster-based permutation tests, false discovery rate control, and control of the generalized FWER. We end with recommendations for their use and introduce free MATLAB software for their implementation. Copyright © 2011 Society for Psychophysiological Research.

Desynchronization in an ensemble of globally coupled chaotic bursting neuronal oscillators by dynamic delayed feedback control

NASA Astrophysics Data System (ADS)

Che, Yanqiu; Yang, Tingting; Li, Ruixue; Li, Huiyan; Han, Chunxiao; Wang, Jiang; Wei, Xile

2015-09-01

In this paper, we propose a dynamic delayed feedback control approach or desynchronization of chaotic-bursting synchronous activities in an ensemble of globally coupled neuronal oscillators. We demonstrate that the difference signal between an ensemble's mean field and its time delayed state, filtered and fed back to the ensemble, can suppress the self-synchronization in the ensemble. These individual units are decoupled and stabilized at the desired desynchronized states while the stimulation signal reduces to the noise level. The effectiveness of the method is illustrated by examples of two different populations of globally coupled chaotic-bursting neurons. The proposed method has potential for mild, effective and demand-controlled therapy of neurological diseases characterized by pathological synchronization.

Moving granular-bed filter development program, Option III: Development of moving granular-bed filter technology for multi-contaminant control. Task 14: Test plan; Topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haas, J.C.; Olivo, C.A.; Wilson, K.B.

1994-04-01

An experimental test plan has been prepared for DOE/METC review and approval to develop a filter media suitable for multi-contaminant control in granular-bed filter (GBF) applications. The plan includes identification, development, and demonstration of methods for enhanced media morphology, chemical reactivity, and mechanical strength. The test plan includes media preparation methods, physical and chemical characterization methods for fresh and reacted media, media evaluation criteria, details of test and analytical equipment, and test matrix of the proposed media testing. A filter media composed of agglomerated limestone and clay was determined to be the best candidate for multi-contaminate control in GBF operation.more » The combined limestone/clay agglomerate has the potential to remove sulfur and alkali species, in addition to particulate, and possibly halogens and trace heavy metals from coal process streams.« less

Fabricating and Controlling Silicon Zigzag Nanowires by Diffusion-Controlled Metal-Assisted Chemical Etching Method.

PubMed

Chen, Yun; Zhang, Cheng; Li, Liyi; Tuan, Chia-Chi; Wu, Fan; Chen, Xin; Gao, Jian; Ding, Yong; Wong, Ching-Ping

2017-07-12

Silicon (Si) zigzag nanowires (NWs) have a great potential in many applications because of its high surface/volume ratio. However, fabricating Si zigzag NWs has been challenging. In this work, a diffusion-controlled metal-assisted chemical etching method is developed to fabricate Si zigzag NWs. By tailoring the composition of etchant to change its diffusivity, etching direction, and etching time, various zigzag NWs can be easily fabricated. In addition, it is also found that a critical length of NW (>1 μm) is needed to form zigzag nanowires. Also, the amplitude of zigzag increases as the location approaches the center of the substrate and the length of zigzag nanowire increases. It is also demonstrated that such zigzag NWs can help the silicon substrate for self-cleaning and antireflection. This method may provide a feasible and economical way to fabricate zigzag NWs and novel structures for broad applications.

Spatially sculpted laser scissors for study of DNA damage and repair

NASA Astrophysics Data System (ADS)

Stephens, Jared; Mohanty, Samarendra K.; Genc, Suzanne; Kong, Xiangduo; Yokomori, Kyoko; Berns, Michael W.

2009-09-01

We present a simple and efficient method for controlled linear induction of DNA damage in live cells. By passing a pulsed laser beam through a cylindrical lens prior to expansion, an elongated elliptical beam profile is created with the ability to expose controlled linear patterns while keeping the beam and the sample stationary. The length and orientation of the beam at the sample plane were reliably controlled by an adjustable aperture and rotation of the cylindrical lens, respectively. Localized immunostaining by the DNA double strand break (DSB) markers phosphorylated H2AX (γH2AX) and Nbs1 in the nuclei of HeLa cells exposed to the ``line scissors'' was shown via confocal imaging. The line scissors method proved more efficient than the scanning mirror and scanning stage methods at induction of DNA DSB damage with the added benefit of having a greater potential for high throughput applications.

Ripple-modulated electronic structure of a 3D topological insulator.

PubMed

Okada, Yoshinori; Zhou, Wenwen; Walkup, D; Dhital, Chetan; Wilson, Stephen D; Madhavan, V

2012-01-01

Three-dimensional topological insulators host linearly dispersing states with unique properties and a strong potential for applications. An important ingredient in realizing some of the more exotic states in topological insulators is the ability to manipulate local electronic properties. Direct analogy to the Dirac material graphene suggests that a possible avenue for controlling local properties is via a controlled structural deformation such as the formation of ripples. However, the influence of such ripples on topological insulators is yet to be explored. Here we use scanning tunnelling microscopy to determine the effects of one-dimensional buckling on the electronic properties of Bi(2)Te(3.) By tracking spatial variations of the interference patterns generated by the Dirac electrons we show that buckling imposes a periodic potential, which locally modulates the surface-state dispersion. This suggests that forming one- and two-dimensional ripples is a viable method for creating nanoscale potential landscapes that can be used to control the properties of Dirac electrons in topological insulators.

CONTROL TECHNOLOGY OVERVIEW REPORT: CFC (CHLOROFLUOROCARBON) EMISSIONS FROM RIGID FOAM MANUFACTURING

EPA Science Inventory

The report estimates total chlorofluorocarbon (CFC) emissions from the various rigid foam manufacturing processes and from the foam products themselves, and examines potential methods for reducing these emissions. Options studied include replacement of CFC-blown products with alt...

An evaluation of several methods for detecting alkali-carbonate reaction.

DOT National Transportation Integrated Search

1972-01-01

Based on the review of previous Council reports, a strategy for the use and control of potentially reactive carbonate rocks is discussed in this report, which lists the previous reports in a bibliography. Specifically, this report discusses an evalua...

EFFECTIVENESS OF SOIL AND WATER CONSERVATION PRACTICES FOR POLLUTION CONTROL

EPA Science Inventory

The potential water quality effects and economic implications of soil and water conservation practices (SWCPs) are identified. Method for estimating the effects of SWCPs on pollutant losses from croplands are presented. Mathematical simulation and linear programming models were u...

Monitoring of International Space Station Telemetry Using Shewhart Control Charts

NASA Technical Reports Server (NTRS)

Fitch, Jeffery T.; Simon, Alan L.; Gouveia, John A.; Hillin, Andrew M.; Hernandez, Steve A.

2012-01-01

Shewhart control charts have been established as an expedient method for analyzing dynamic, trending data in order to identify anomalous subsystem performance as soon as such performance would exceed a statistically established baseline. Additionally, this leading indicator tool integrates a selection methodology that reduces false positive indications, optimizes true leading indicator events, minimizes computer processor unit duty cycles, and addresses human factor concerns (i.e., the potential for flight-controller data overload). This innovation leverages statistical process control, and provides a relatively simple way to allow flight controllers to focus their attention on subtle system changes that could lead to dramatic off-nominal system performance. Finally, this capability improves response time to potential hardware damage and/or crew injury, thereby improving space flight safety. Shewhart control charts require normalized data. However, the telemetry from the ISS Early External Thermal Control System (EETCS) was not normally distributed. A method for normalizing the data was implemented, as was a means of selecting data windows, the number of standard deviations (Sigma Level), the number of consecutive points out of limits (Sequence), and direction (increasing or decreasing trend data). By varying these options, and treating them like dial settings, the number of nuisance alerts and leading indicators were optimized. The goal was to capture all leading indicators while minimizing the number of nuisances. Lean Six Sigma (L6S) design of experiment methodologies were employed. To optimize the results, Perl programming language was used to automate the massive amounts of telemetry data, control chart plots, and the data analysis.

Evaluation of landscape coverings to reduce soil lead hazards in urban residential yards: The Safer Yards Project.

PubMed

Binns, Helen J; Gray, Kimberly A; Chen, Tianyue; Finster, Mary E; Peneff, Nicholas; Schaefer, Peter; Ovsey, Victor; Fernandes, Joyce; Brown, Mavis; Dunlap, Barbara

2004-10-01

This study was designed primarily to evaluate the effectiveness of landscape coverings to reduce the potential for exposure to lead-contaminated soil in an urban neighborhood. Residential properties were randomized in to three groups: application of ground coverings/barriers plus placement of a raised garden bed (RB), application of ground coverings/barriers only (no raised bed, NRB), and control. Outcomes evaluated soil lead concentration (employing a weighting method to assess acute hazard soil lead [areas not fully covered] and potential hazard soil lead [all soil surfaces regardless of covering status]), density of landscape coverings (6 = heavy, > 90% covered; 1 = bare, < 10% covered), lead tracked onto carpeted entryway floor mats, and entryway floor dust lead loadings. Over 1 year, the intervention groups had significantly reduced acute hazard soil lead concentration (median change: RB, -478 ppm; NRB, -698 ppm; control, +52 ppm; Kruskal-Wallis, P = 0.02), enhanced landscape coverings (mean change in score: RB, +0.6; NRB, +1.5; control, -0.6; ANOVA, P < 0.001), and a 50% decrease in lead tracked onto the floor mats. The potential hazard soil lead concentration and the entryway floor dust lead loading did not change significantly. Techniques evaluated by this study are feasible for use by property owners but will require continued maintenance. The long-term sustainability of the method needs further examination.

Quality control and in vitro antioxidant potential of Coriandrum sativum Linn.

PubMed Central

Singh, Mhaveer; Tamboli, E. T.; Kamal, Y. T.; Ahmad, Wasim; Ansari, S. H.; Ahmad, Sayeed

2015-01-01

Background: Coriandrum sativum Linn., commonly known as coriander, is a well-known spice and drug in India. It has various health-related benefits and used in various Unani formulations. In this present study, quality assessment of coriander fruits was carried out by studying anatomical characters, physicochemical tests, and chemoprofiling using high performance thin layer chromatography (HPTLC) and gas chromatography-mass spectroscopy (GC-MS) along with in vitro antioxidant potential. Materials and Methods: Standardization was carried out as per the pharmacopeial guidelines. Estimation of heavy metals, pesticides, and aflatoxins was carried out to ascertain the presence of any contaminant in the sample. Chemoprofiling was achieved by thin layer chromatography (TLC) by optimizing the mobile phase for different extracts. The most of the pharmacological activities of coriander are based on volatile oil constituents. Hence, GC-MS profiling was also carried out using hexane-soluble fraction of hydro-alcoholic extract. The total phenolic contents and in vitro antioxidant efficacy were determined using previously established methods. Results: The quality control and anatomical studies were very valuable for the identification whereas good antioxidant potential was observed when compared to ascorbic acid. The drug was found free of contaminant when analyzed for pesticides and aflatoxins whereas heavy metals were found under reported limits. Conclusion: The work embodied in this present research can be utilized for the identification and the quality control of the coriander fruit. PMID:26681883

Method and apparatus for synthesizing anhydrous HNO.sub.3

DOEpatents

Coon, Clifford L.; Harrar, Jackson E.; Pearson, Richard K.; McGuire, Raymond R.

1984-01-01

A method and apparatus for electrochemically synthesizing anhydrous HNO.sub.3 from an aqueous solution of HNO.sub.3 includes oxidizing a solution of N.sub.2 O.sub.4 /aqueous HNO.sub.3 at an anode, while maintaining a controlled potential between the N.sub.2 O.sub.4 /aqueous HNO.sub.3 solution and the anode. A potential of about 1.80V vs. SCE is preferred. Anhydrous or aqueous HNO.sub.3 may be disposed at the cathode within the electrochemical cell. Aqueous HNO.sub.3 having a water content of up to about 12% by weight is utilized to synthesize anhydrous HNO.sub.3.

Method and apparatus for synthesizing anhydrous HNO/sub 3/. [Patent application

DOEpatents

Coon, C.L.; Harrar, J.E.; Pearson, R.K.; McGuire, R.R.

1982-07-20

A method and apparatus for electrochemically synthesizing anhydrous HNO/sub 3/ from an aqueous solution of HNO/sub 3/- includes oxidizing a solution of N/sub 2/O/sub 4//aqueous HNO/sub 3/ at an anode, while maintaining a controlled potential between the N/sub 2/O/sub 4//aqueous HNO/sub 3/ solution and the anode. A potential of about 1.80V vs. SCE is preferred. Anhydrous or aqueous HNO/sub 3/ may be disposed at the cathode within the electrochemical cell. Aqueous HNO/sub 3/ having a water content of up to about 12% by weight is utilized to synthesize anhydrous HNO/sub 3/.

Endocochlear potential generation is associated with intercellular communication in the stria vascularis: structural analysis in the viable dominant spotting mouse mutant.

PubMed

Carlisle, L; Steel, K; Forge, A

1990-11-01

Deafness in the viable dominant spotting mouse mutant is due to a primary defect of the stria vascularis which results in absence of the positive endocochlear potential in scala media. Endocochlear potentials were measured and the structure of stria vascularis of mutants with potentials close to zero was compared with that in normal littermate controls by use of morphometric methods. The stria vascularis was significantly thinner in mutants. Marginal cells were not significantly different from controls in terms of volume density or intramembrane particle density but the network density of tight junctions was significantly reduced in the mutants. A virtual absence of gap junctions between basal cells and marginal or intermediate cells was observed, but intramembrane particle density and junctional complexes between adjacent basal cells were not different from controls. The volume density of basal cells was significantly greater in mutants. Intermediate cells accounted for a significantly smaller volume density of the stria vascularis in mutants and had a lower density of intramembrane particles than controls. Melanocytes were not identified in the stria vascularis of mutants. These results suggest that communication between marginal, intermediate and basal cells might be important to the normal function of the stria vascularis.

Cleaning method and apparatus

DOEpatents

Jackson, D.D.; Hollen, R.M.

1981-02-27

A method of very thoroughly and quikcly cleaning a guaze electrode used in chemical analyses is given, as well as an automobile cleaning apparatus which makes use of the method. The method generates very little waste solution, and this is very important in analyzing radioactive materials, especially in aqueous solutions. The cleaning apparatus can be used in a larger, fully automated controlled potential coulometric apparatus. About 99.98% of a 5 mg plutonium sample was removed in less than 3 minutes, using only about 60 ml of rinse solution and two main rinse steps.

Development of a colony hybridization method for the enumeration of total and potentially enteropathogenic Vibrio parahaemolyticus in shellfish.

PubMed

Suffredini, Elisabetta; Cozzi, Loredana; Ciccaglioni, Gianni; Croci, Luciana

2014-09-01

Vibrio parahaemolyticus is a marine microorganism, recognized as cause of gastroenteritis outbreaks associated with seafood consumption. In this study the development and the in-house validation of a colony hybridization method for the enumeration of total and potentially pathogenic V. parahaemolyticus is reported. The method included a set of three controls (process, hybridization and detection control) for the full monitoring of the analytical procedure. Four digoxigenin-labeled probes were designed for pathogenic strains enumeration (tdh1, tdh2, trh1 and trh2 probes) and one for total V. parahaemolyticus count (toxR probe). Probes were tested on a panel of 70 reference strains and 356 environmental, food and clinical isolates, determining the inclusivity (tdh: 96.7%, trh: 97.8%, toxR: 99.4%) and the exclusivity (100% for all probes). Accuracy and linearity of the enumeration were evaluated on pure and mixed cultures: slopes of the regression lines ranged from 0.957 to 1.058 depending on the target gene and R(2) was greater than or equal to 0.989 for all reactions. Evaluation was also carried on using four experimentally contaminated seafood matrices (shellfish, finfish, crustaceans and cephalopods) and the slopes of the curves varied from 0.895 (finfish) to 0.987 (cephalopods) for the counts of potentially pathogenic V. parahaemolyticus (R(2)≥0.965) and from 0.965 to 1.073 for total V. parahaemolyticus enumeration (R(2)≥0.981). Validation was performed on 104 naturally contaminated shellfish samples, analyzed in parallel by colony hybridization, ISO/TS 21872-1 and MPN enumeration. Colony hybridization and ISO method showed a relative accuracy of 86.7%, and a statistically significant correlation was present between colony hybridization enumeration and MPN results (r=0.744, p<0.001). The proposed colony hybridization can be a suitable alternative method for the enumeration of total and potentially pathogenic V. parahaemolyticus in seafood. Copyright © 2014 Elsevier B.V. All rights reserved.

Robotic Exoskeletons: A Perspective for the Rehabilitation of Arm Coordination in Stroke Patients

PubMed Central

Jarrassé, Nathanaël; Proietti, Tommaso; Crocher, Vincent; Robertson, Johanna; Sahbani, Anis; Morel, Guillaume; Roby-Brami, Agnès

2014-01-01

Upper-limb impairment after stroke is caused by weakness, loss of individual joint control, spasticity, and abnormal synergies. Upper-limb movement frequently involves abnormal, stereotyped, and fixed synergies, likely related to the increased use of sub-cortical networks following the stroke. The flexible coordination of the shoulder and elbow joints is also disrupted. New methods for motor learning, based on the stimulation of activity-dependent neural plasticity have been developed. These include robots that can adaptively assist active movements and generate many movement repetitions. However, most of these robots only control the movement of the hand in space. The aim of the present text is to analyze the potential of robotic exoskeletons to specifically rehabilitate joint motion and particularly inter-joint coordination. First, a review of studies on upper-limb coordination in stroke patients is presented and the potential for recovery of coordination is examined. Second, issues relating to the mechanical design of exoskeletons and the transmission of constraints between the robotic and human limbs are discussed. The third section considers the development of different methods to control exoskeletons: existing rehabilitation devices and approaches to the control and rehabilitation of joint coordinations are then reviewed, along with preliminary clinical results available. Finally, perspectives and future strategies for the design of control mechanisms for rehabilitation exoskeletons are discussed. PMID:25520638

Self assembled linear polymeric chains with tuneable semiflexibility using isotropic interactions.

PubMed

Abraham, Alex; Chatterji, Apratim

2018-04-21

We propose a two-body spherically symmetric (isotropic) potential such that particles interacting by the potential self-assemble into linear semiflexible polymeric chains without branching. By suitable control of the potential parameters, we can control the persistence length of the polymer and can even introduce a controlled number of branches. Thus we show how to achieve effective directional interactions starting from spherically symmetric potentials. The self-assembled polymers have an exponential distribution of chain lengths akin to what is observed for worm-like micellar systems. On increasing particle density, the polymeric chains self-organize to an ordered line-hexagonal phase where every chain is surrounded by six parallel chains, the transition is first order. On further increase in monomer density, the order is destroyed and we get a branched gel-like phase. This potential can be used to model semi-flexible equilibrium polymers with tunable semiflexibility and excluded volume. The use of the potential is computationally cheap and hence can be used to simulate and probe equilibrium polymer dynamics with long chains. The potential also gives a plausible method of tuning colloidal interactions in experiments such that one can obtain self-assembling polymeric chains made up of colloids and probe polymer dynamics using an optical microscope. Furthermore, we show how a modified potential leads to the observation of an intermediate nematic phase of self-assembled chains in between the low density disordered phase and the line-ordered hexagonal phase.

Self assembled linear polymeric chains with tuneable semiflexibility using isotropic interactions

NASA Astrophysics Data System (ADS)

Abraham, Alex; Chatterji, Apratim

2018-04-01

We propose a two-body spherically symmetric (isotropic) potential such that particles interacting by the potential self-assemble into linear semiflexible polymeric chains without branching. By suitable control of the potential parameters, we can control the persistence length of the polymer and can even introduce a controlled number of branches. Thus we show how to achieve effective directional interactions starting from spherically symmetric potentials. The self-assembled polymers have an exponential distribution of chain lengths akin to what is observed for worm-like micellar systems. On increasing particle density, the polymeric chains self-organize to an ordered line-hexagonal phase where every chain is surrounded by six parallel chains, the transition is first order. On further increase in monomer density, the order is destroyed and we get a branched gel-like phase. This potential can be used to model semi-flexible equilibrium polymers with tunable semiflexibility and excluded volume. The use of the potential is computationally cheap and hence can be used to simulate and probe equilibrium polymer dynamics with long chains. The potential also gives a plausible method of tuning colloidal interactions in experiments such that one can obtain self-assembling polymeric chains made up of colloids and probe polymer dynamics using an optical microscope. Furthermore, we show how a modified potential leads to the observation of an intermediate nematic phase of self-assembled chains in between the low density disordered phase and the line-ordered hexagonal phase.

Vector-control personnel’s knowledge, perceptions and practices towards insecticides used for indoor residual spraying in Limpopo Province, South Africa

PubMed Central

2013-01-01

Background Contradictory arguments regarding the benefits and harm of insecticides, especially DDT, have caused concerns in different societal circles, threatening to undermine the achievements of the indoor residual spraying (IRS) programme in South Africa. These concerns were exacerbated by the screening of a documentary on South African Broadcasting Corporation (SABC) Television with anti-DDT sentiments. Consequently, Limpopo Malaria Control Programme (LMCP) Management advocated for an investigation to determine the potential effect of such campaigns on vector-control personnel’s knowledge and perceived effects of insecticides on human health, with a view to improving the educational materials designed for use in training vector-control personnel. Methods The study was a cross-sectional descriptive survey using a structured field-piloted questionnaire, administered to 233 randomly selected vector-control personnel. Ethical clearance was granted by the University of KwaZulu-Natal. Approval for the study was granted by the Department of Health, Limpopo. Participation in the study was voluntary and all respondents signed informed consent. Descriptive statistics were used to analyse the collected data. Results Most respondents (96.6%) had a positive perception of IRS as a method to control malaria. Despite their positive perception, 93.6% viewed IRS insecticides to be potentially harmful to the users. DDT was perceived to cause long-term reproductive and respiratory effects, whereas alpha-cypermethrin and deltamethrin were largely associated with skin irritation/itchiness and skin burn. Study participants were more worried about DDT’s potential effects on their reproductive system, including poor sexual performance, decline in libido, miscarriage and bearing children with genetic defects. However, none reported personal experience of bearing a child with genetic defects or miscarriage. Most anti-insecticide messages, especially relating to DDT, emanated from sources external to the LMCP, mainly through radio (62%) and television (33.9%) and about 70% believed such messages. While most respondents preferred to work with a moderately itchy deltamethrin, DDT was admittedly the most effective insecticide. Conclusion Vector-control personnel faced health and ethical dilemmas, in that, while they perceived insecticides used for IRS in Limpopo to be potentially harmful to the health of users, as purported through media, they also viewed IRS using insecticides to be effective in controlling malaria. PMID:23618516

Realization of the three-qubit quantum controlled gate based on matching Hermitian generators

NASA Astrophysics Data System (ADS)

Gautam, Kumar; Rawat, Tarun Kumar; Parthasarathy, Harish; Sharma, Navneet; Upadhyaya, Varun

2017-05-01

This paper deals with the design of quantum unitary gate by matching the Hermitian generators. A given complicated quantum controlled gate is approximated by perturbing a simple quantum system with a small time-varying potential. The basic idea is to evaluate the generator H_φ of the perturbed system approximately using first-order perturbation theory in the interaction picture. H_φ depends on a modulating signal φ(t){:} 0≤t≤T which modulates a known potential V. The generator H_φ of the given gate U_g is evaluated using H_g=ι log U_g. The optimal modulating signal φ(t) is chosen so that \\Vert H_g - H_φ \\Vert is a minimum. The simple quantum system chosen for our simulation is harmonic oscillator with charge perturbed by an electric field that is a constant in space but time varying and is controlled externally. This is used to approximate the controlled unitary gate obtained by perturbing the oscillator with an anharmonic term proportional to q^3. Simulations results show significantly small noise-to-signal ratio. Finally, we discuss how the proposed method is particularly suitable for designing some commonly used unitary gates. Another example was chosen to illustrate this method of gate design is the ion-trap model.

Evolutionary Computation with Spatial Receding Horizon Control to Minimize Network Coding Resources

PubMed Central

Leeson, Mark S.

2014-01-01

The minimization of network coding resources, such as coding nodes and links, is a challenging task, not only because it is a NP-hard problem, but also because the problem scale is huge; for example, networks in real world may have thousands or even millions of nodes and links. Genetic algorithms (GAs) have a good potential of resolving NP-hard problems like the network coding problem (NCP), but as a population-based algorithm, serious scalability and applicability problems are often confronted when GAs are applied to large- or huge-scale systems. Inspired by the temporal receding horizon control in control engineering, this paper proposes a novel spatial receding horizon control (SRHC) strategy as a network partitioning technology, and then designs an efficient GA to tackle the NCP. Traditional network partitioning methods can be viewed as a special case of the proposed SRHC, that is, one-step-wide SRHC, whilst the method in this paper is a generalized N-step-wide SRHC, which can make a better use of global information of network topologies. Besides the SRHC strategy, some useful designs are also reported in this paper. The advantages of the proposed SRHC and GA for the NCP are illustrated by extensive experiments, and they have a good potential of being extended to other large-scale complex problems. PMID:24883371

Accurately controlled sequential self-folding structures by polystyrene film

NASA Astrophysics Data System (ADS)

Deng, Dongping; Yang, Yang; Chen, Yong; Lan, Xing; Tice, Jesse

2017-08-01

Four-dimensional (4D) printing overcomes the traditional fabrication limitations by designing heterogeneous materials to enable the printed structures evolve over time (the fourth dimension) under external stimuli. Here, we present a simple 4D printing of self-folding structures that can be sequentially and accurately folded. When heated above their glass transition temperature pre-strained polystyrene films shrink along the XY plane. In our process silver ink traces printed on the film are used to provide heat stimuli by conducting current to trigger the self-folding behavior. The parameters affecting the folding process are studied and discussed. Sequential folding and accurately controlled folding angles are achieved by using printed ink traces and angle lock design. Theoretical analyses are done to guide the design of the folding processes. Programmable structures such as a lock and a three-dimensional antenna are achieved to test the feasibility and potential applications of this method. These self-folding structures change their shapes after fabrication under controlled stimuli (electric current) and have potential applications in the fields of electronics, consumer devices, and robotics. Our design and fabrication method provides an easy way by using silver ink printed on polystyrene films to 4D print self-folding structures for electrically induced sequential folding with angular control.

Identification and evaluation of semiochemicals for the biological control of the beetle Omorgus suberosus (F.) (Coleoptera: Trogidae), a facultative predator of eggs of the sea turtle Lepidochelys olivacea (Eschscholtz).

PubMed

Cortez, Vieyle; Verdú, José R; Ortiz, Antonio J; Halffter, Gonzalo

2017-01-01

The beetle Omorgus suberosus (F.) is a facultative predator of eggs of the olive ridley turtle Lepidochelys olivacea (Eschscholtz). Laboratory and field investigations were conducted in order to characterize volatile attractants of O. suberosus and to explore the potential for application of these volatiles in a selective mass trapping method. Headspace sorptive extraction (HSSE) coupled to thermo-desorption gas chromatography-mass spectrometry (TD-GC-MS) analysis of the volatile constituents from beetles or turtle nests revealed 24 potential compounds. However, electroantennographic (EAG) measurements revealed antennal sensitivity only to indole, linoleic acid, trimethylamine, dimethyl sulphide, dimethyl disulphide and ammonia. Behavioural tests showed that these compounds are highly attractive to O. suberosus. Field trapping experiments revealed that indole and ammonia were more attractive than the other volatile compounds and showed similar attractiveness to that produced by conventional baits (chicken feathers). The use of a combined bait of indole and NH3 would therefore be the most effective trap design. The data presented are the first to demonstrate effective massive capture of O. suberosus using an attractant-based trapping method. These findings have potential for the development of an efficient mass trapping method for control of this beetle as part of efforts towards conservation of L. olivacea at La Escobilla in Oaxaca, Mexico.

Identification and evaluation of semiochemicals for the biological control of the beetle Omorgus suberosus (F.) (Coleoptera: Trogidae), a facultative predator of eggs of the sea turtle Lepidochelys olivacea (Eschscholtz)

PubMed Central

Cortez, Vieyle; Ortiz, Antonio J.; Halffter, Gonzalo

2017-01-01

The beetle Omorgus suberosus (F.) is a facultative predator of eggs of the olive ridley turtle Lepidochelys olivacea (Eschscholtz). Laboratory and field investigations were conducted in order to characterize volatile attractants of O. suberosus and to explore the potential for application of these volatiles in a selective mass trapping method. Headspace sorptive extraction (HSSE) coupled to thermo-desorption gas chromatography–mass spectrometry (TD-GC-MS) analysis of the volatile constituents from beetles or turtle nests revealed 24 potential compounds. However, electroantennographic (EAG) measurements revealed antennal sensitivity only to indole, linoleic acid, trimethylamine, dimethyl sulphide, dimethyl disulphide and ammonia. Behavioural tests showed that these compounds are highly attractive to O. suberosus. Field trapping experiments revealed that indole and ammonia were more attractive than the other volatile compounds and showed similar attractiveness to that produced by conventional baits (chicken feathers). The use of a combined bait of indole and NH3 would therefore be the most effective trap design. The data presented are the first to demonstrate effective massive capture of O. suberosus using an attractant-based trapping method. These findings have potential for the development of an efficient mass trapping method for control of this beetle as part of efforts towards conservation of L. olivacea at La Escobilla in Oaxaca, Mexico. PMID:28192472

A simple ERP method for quantitative analysis of cognitive workload in myoelectric prosthesis control and human-machine interaction.

PubMed

Deeny, Sean; Chicoine, Caitlin; Hargrove, Levi; Parrish, Todd; Jayaraman, Arun

2014-01-01

Common goals in the development of human-machine interface (HMI) technology are to reduce cognitive workload and increase function. However, objective and quantitative outcome measures assessing cognitive workload have not been standardized for HMI research. The present study examines the efficacy of a simple event-related potential (ERP) measure of cortical effort during myoelectric control of a virtual limb for use as an outcome tool. Participants trained and tested on two methods of control, direct control (DC) and pattern recognition control (PRC), while electroencephalographic (EEG) activity was recorded. Eighteen healthy participants with intact limbs were tested using DC and PRC under three conditions: passive viewing, easy, and hard. Novel auditory probes were presented at random intervals during testing, and significant task-difficulty effects were observed in the P200, P300, and a late positive potential (LPP), supporting the efficacy of ERPs as a cognitive workload measure in HMI tasks. LPP amplitude distinguished DC from PRC in the hard condition with higher amplitude in PRC, consistent with lower cognitive workload in PRC relative to DC for complex movements. Participants completed trials faster in the easy condition using DC relative to PRC, but completed trials more slowly using DC relative to PRC in the hard condition. The results provide promising support for ERPs as an outcome measure for cognitive workload in HMI research such as prosthetics, exoskeletons, and other assistive devices, and can be used to evaluate and guide new technologies for more intuitive HMI control.

Cleaning method and apparatus

DOEpatents

Jackson, Darryl D.; Hollen, Robert M.

1983-01-01

A new automatable cleaning apparatus which makes use of a method of very thoroughly and quickly cleaning a gauze electrode used in chemical analyses is given. The method generates very little waste solution, and this is very important in analyzing radioactive materials, especially in aqueous solutions. The cleaning apparatus can be used in a larger, fully automated controlled potential coulometric apparatus. About 99.98% of a 5 mg. plutonium sample was removed in less than 3 minutes, using only about 60 ml. of rinse solution and two main rinse steps.

Coordinated Control of Cross-Flow Turbines

NASA Astrophysics Data System (ADS)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2016-11-01

Cross-flow turbines, also known as vertical-axis turbines, have several advantages over axial-flow turbines for a number of applications including urban wind power, high-density arrays, and marine or fluvial currents. By controlling the angular velocity applied to the turbine as a function of angular blade position, we have demonstrated a 79 percent increase in cross-flow turbine efficiency over constant-velocity control. This strategy uses the downhill simplex method to optimize control parameter profiles during operation of a model turbine in a recirculating water flume. This optimization method is extended to a set of two turbines, where the blade motions and position of the downstream turbine are optimized to beneficially interact with the coherent structures in the wake of the upstream turbine. This control scheme has the potential to enable high-density arrays of cross-flow turbines to operate at cost-effective efficiency. Turbine wake and force measurements are analyzed for insight into the effect of a coordinated control strategy.

Robust Control for Microgravity Vibration Isolation using Fixed Order, Mixed H2/Mu Design

NASA Technical Reports Server (NTRS)

Whorton, Mark

2003-01-01

Many space-science experiments need an active isolation system to provide a sufficiently quiescent microgravity environment. Modern control methods provide the potential for both high-performance and robust stability in the presence of parametric uncertainties that are characteristic of microgravity vibration isolation systems. While H2 and H(infinity) methods are well established, neither provides the levels of attenuation performance and robust stability in a compensator with low order. Mixed H2/H(infinity), controllers provide a means for maximizing robust stability for a given level of mean-square nominal performance while directly optimizing for controller order constraints. This paper demonstrates the benefit of mixed norm design from the perspective of robustness to parametric uncertainties and controller order for microgravity vibration isolation. A nominal performance metric analogous to the mu measure, for robust stability assessment is also introduced in order to define an acceptable trade space from which different control methodologies can be compared.

Comparison of methods for the analysis of relatively simple mediation models.

PubMed

Rijnhart, Judith J M; Twisk, Jos W R; Chinapaw, Mai J M; de Boer, Michiel R; Heymans, Martijn W

2017-09-01

Statistical mediation analysis is an often used method in trials, to unravel the pathways underlying the effect of an intervention on a particular outcome variable. Throughout the years, several methods have been proposed, such as ordinary least square (OLS) regression, structural equation modeling (SEM), and the potential outcomes framework. Most applied researchers do not know that these methods are mathematically equivalent when applied to mediation models with a continuous mediator and outcome variable. Therefore, the aim of this paper was to demonstrate the similarities between OLS regression, SEM, and the potential outcomes framework in three mediation models: 1) a crude model, 2) a confounder-adjusted model, and 3) a model with an interaction term for exposure-mediator interaction. Secondary data analysis of a randomized controlled trial that included 546 schoolchildren. In our data example, the mediator and outcome variable were both continuous. We compared the estimates of the total, direct and indirect effects, proportion mediated, and 95% confidence intervals (CIs) for the indirect effect across OLS regression, SEM, and the potential outcomes framework. OLS regression, SEM, and the potential outcomes framework yielded the same effect estimates in the crude mediation model, the confounder-adjusted mediation model, and the mediation model with an interaction term for exposure-mediator interaction. Since OLS regression, SEM, and the potential outcomes framework yield the same results in three mediation models with a continuous mediator and outcome variable, researchers can continue using the method that is most convenient to them.

Non-contraceptive benefits of hormonal and intrauterine reversible contraceptive methods.

PubMed

Bahamondes, Luis; Valeria Bahamondes, M; Shulman, Lee P

2015-01-01

Most contraceptive methods present benefits beyond contraception; however, despite a large body of evidence, many healthcare professionals (HCPs), users and potential users are unaware of those benefits. This review evaluates the evidence for non-contraceptive benefits of hormonal and non-hormonal contraceptive methods. We searched the medical publications in PubMed, POPLINE, CENTRAL, EMBASE and LILACS for relevant articles, on non-contraceptive benefits of the use of hormonal and intrauterine reversible contraceptive methods, which were published in English between 1980 and July 2014. Articles were identified using the following search terms: 'contraceptive methods', 'benefits', 'cancer', 'anaemia', 'heavy menstrual bleeding (HMB)', 'endometrial hyperplasia', 'endometriosis' and 'leiomyoma'. We identified, through the literature search, evidence that some combined oral contraceptives have benefits in controlling HMB and anaemia, reducing the rate of endometrial, ovarian and colorectal cancer and ectopic pregnancy as well as alleviating symptoms of premenstrual dysphoric disorder. Furthermore, the use of the levonorgestrel-releasing intrauterine system also controls HMB and anaemia and endometrial hyperplasia and cancer, reduces rates of endometrial polyps in users of tamoxifen and alleviates pain associated with endometriosis and adenomyosis. Depot medroxyprogesterone acetate controls crises of pain associated with sickle cell disease and endometriosis. Users of the etonogestrel-releasing contraceptive implant have the benefits of a reduction of pain associated with endometriosis, and users of the copper intrauterine device have reduced rates of endometrial and cervical cancer. Despite the high contraceptive effectiveness of many hormonal and intrauterine reversible contraceptive methods, many HCPs, users and potential users are concerned mainly about side effects and safety of both hormonal and non-hormonal contraceptive methods, and there is scarce information about the many benefits that these methods offer beyond contraception. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

On the Definition of Surface Potentials for Finite-Difference Operators

NASA Technical Reports Server (NTRS)

Tsynkov, S. V.; Bushnell, Dennis M. (Technical Monitor)

2001-01-01

For a class of linear constant-coefficient finite-difference operators of the second order, we introduce the concepts similar to those of conventional single- and double-layer potentials for differential operators. The discrete potentials are defined completely independently of any notion related to the approximation of the continuous potentials on the grid. We rather use all approach based on differentiating, and then inverting the differentiation of a function with surface discontinuity of a particular kind, which is the most general way of introducing surface potentials in the theory of distributions. The resulting finite-difference "surface" potentials appear to be solutions of the corresponding continuous potentials. Primarily, this pertains to the possibility of representing a given solution to the homogeneous equation on the domain as a variety of surface potentials, with the density defined on the domain's boundary. At the same time the discrete surface potentials can be interpreted as one specific realization of the generalized potentials of Calderon's type, and consequently, their approximation properties can be studied independently in the framework of the difference potentials method by Ryaben'kii. The motivation for introducing and analyzing the discrete surface potentials was provided by the problems of active shielding and control of sound, in which the aforementioned source terms that drive the potentials are interpreted as the acoustic control sources that cancel out the unwanted noise on a predetermined region of interest.

Rapid New Methods for Paint Collection and Lead Extraction

EPA Science Inventory

Chronic exposure of children to lead (Ph) can result in permanent physiologic impairment. In adults, it can cause irritability, poor muscle coordination, and nerve damage to the sense organs and nerves controlling the body. Surfaces coated with Pb-containing paints are potential ...

A spectral method for spatial downscaling

EPA Science Inventory

Complex computer models play a crucial role in air quality research. These models are used to evaluate potential regulatory impacts of emission control strategies and to estimate air quality in areas without monitoring data. For both of these purposes, it is important to calibrat...

Exposure assessment and risk management of engineered nanoparticles: Investigation in semiconductor wafer processing

NASA Astrophysics Data System (ADS)

Shepard, Michele N.

Engineered nanomaterials (ENMs) are currently used in hundreds of commercial products and industrial processes, with more applications being investigated. Nanomaterials have unique properties that differ from bulk materials. While these properties may enable technological advancements, the potential risks of ENMs to people and the environment are not yet fully understood. Certain low solubility nanoparticles are more toxic than their bulk material, such that existing occupational exposure limits may not be sufficiently protective for workers. Risk assessments are currently challenging due to gaps in data on the numerous emerging materials and applications as well as method uncertainties and limitations. Chemical mechanical planarization (CMP) processes with engineered nanoparticle abrasives are used for research and commercial manufacturing applications in the semiconductor and related industries. Despite growing use, no published studies addressed occupational exposures to nanoparticles associated with CMP or risk assessment and management practices for these scenarios. Additional studies are needed to evaluate potential sources of workplace exposure or emission, as well as to help test and refine assessment methods. This research was conducted to: identify the lifecycle stages and potential exposure sources for ENMs in CMP processes; characterize worker exposure; determine recommended engineering controls and compare risk assessment models. The study included workplace air and surface sampling and an evaluation of qualitative risk banding approaches. Exposure assessment results indicated the potential for worker contact with ENMs on workplace surfaces but did not identify nanoparticles readily dispersed in air during work tasks. Some increases in respirable particle concentrations were identified, but not consistently. Measured aerosol concentrations by number and mass were well below current reference values for poorly soluble low toxicity nanoparticles. From application and evaluation of qualitative risk assessment approaches, differences in control banding models and results were identified, although output generally agreed with conclusions from air sampling as to whether an upgrade in site engineering controls was recommended. This research helped to improve understanding of potential worker exposures to ENMs in CMP processes, as well as the methods for risk assessment and management of metal oxide nanoparticles in occupational environments.

Method and apparatus for electrokinetic transport

NASA Technical Reports Server (NTRS)

James, Patrick Ismail (Inventor); Stejic, George (Inventor)

2012-01-01

Controlled electrokinetic transport of constituents of liquid media can be achieved by connecting at least two volumes containing liquid media with at least one dielectric medium with opposing dielectric surfaces in direct contact with said liquid media, and establishing at least one conduit across said dielectric medium, with a conduit inner surface surrounding a conduit volume and at least a first opening and a second opening opposite to the first opening. The conduit is arranged to connect two volumes containing liquid media and includes a set of at least three electrodes positioned in proximity of the inner conduit surface. A power supply is arranged to deliver energy to the electrodes such that time-varying potentials inside the conduit volume are established, where the superposition of said potentials represents at least one controllable traveling potential well that can travel between the opposing conduit openings.

EVA Hazards due to TPS Inspection and Repair

NASA Technical Reports Server (NTRS)

Stewart, Christine E.

2007-01-01

Tile inspection and repair activities have implicit hazards associated with them. When an Extra Vehicular Activities (EVA) crewmember and associated hardware are added into the equation, additional hazards are introduced. Potential hazards to the Extravehicular Mobility Unit (EMU), the Orbiter or the crew member themselves are created. In order to accurately assess the risk of performing a TPS inspection or repair, an accurate evaluation of potential hazards and how adequately these hazards are controlled is essential. The EMU could become damaged due to sharp edges, protrusions, thermal extremes, molten metal or impact with the Orbiter. Tools, tethers and the presence of a crew member in the vicinity of the Orbiter Thermal Protection System (TPS) pose hazards to the Orbiter. Hazards such as additional tile or Reinforced Carbon-Carbon (RCC) damage from a loose tool, safety tethers, crewmember or arm impact are introduced. Additionally, there are hazards to the crew which should be addressed. Crew hazards include laser injury, electrical shock, inability to return to the airlock for EMU failures or Orbiter rapid safing scenarios, as well as the potential inadvertent release of a crew member from the arm/boom. The aforementioned hazards are controlled in various ways. Generally, these controls are addressed operationally versus by design, as the majority of the interfaces are to the Orbiter and the Orbiter design did not originally account for tile repair. The Shuttle Remote Manipulator System (SRMS), for instance, was originally designed to deploy experiments, and therefore has insufficient design controls for retention of the Orbiter Boom Sensor System (OBSS). Although multiple methods to repair the Orbiter TPS exist, the majority of the hazards are applicable no matter which specific repair method is being performed. TPS Inspection performed via EVA also presents some of the same hazards. Therefore, the hazards common to all TPS inspection or repair methods will be addressed.

A New Method for the Adaptive Control of Vortex-Wall Interactions

NASA Technical Reports Server (NTRS)

Koumoutsakos, P.

1996-01-01

The control of vortical flows is gaining significance in the design of aeronautical and marine structures. While passive devices have been used effectively in the past, active control strategies have the potential of allowing a leap in the performance of future configurations. The efficiency of control schemes is strongly dependent on the development of accurate flow models that can be devised using information that is available not only from numerical solutions of the governing Navier-Stokes equations but also can be measured experimentally. In that context it is desirable to construct adaptive control schemes using information that can be measured at the wall.

Evaluation of thrombolytic potential of three medicinal plants available in Bangladesh, as a potent source of thrombolytic compounds.

PubMed

Ramjan, Ali; Hossain, Marjan; Runa, Jannatul Ferdous; Md, Hasanuzzaman; Mahmodul, Islam

2014-11-01

The present study is aimed to investigate in vitro thrombolytic activity of three Bangladeshi medicinal plants Averrhoa bilimbi (Oxalidiaceae), Clerodendrum viscosum (Verbanaceae) and Drynaria quercifolia (Polypodiaceae). Each the plant was extracted with methanol at room temperature and the concentrated methanolic extracts (MEF) were fractionated by the modified Kupchan partitioning method to render pet-ether soluble fraction (PESF), carbon tetrachloride soluble fraction (CTSF), chloroform soluble fraction (CSF) and aqueous soluble fraction (AQSF). To observe their thrombolytic potential, a prompt and swift method was involved where streptokinase and water were used as positive and negative control, respectively. Among the three plants, AQSF and PESF of D. quercifolia with CTSF of C. viscosum exhibited highest thrombolytic activity by clot lysis of 34.38%, 34.27% and 28.64%, respectively. Among other extracts A. bilimbi, C. viscosun and D.quercifolia showed significant percentage (%) of clot lysis compared to standard streptokinase (41.05%) while the negative control water revealed 3.31 % lysis of clot. From our findings it is observed that all the plants revealed remarkable thrombolytic activity. Therefore, steps should be taken to observe in vivo clot dissolving potential and to isolate active component(s) of these extracts.

Magnetic steering control of multi-cellular bio-hybrid microswimmers.

PubMed

Carlsen, Rika Wright; Edwards, Matthew R; Zhuang, Jiang; Pacoret, Cecile; Sitti, Metin

2014-10-07

Bio-hybrid devices, which integrate biological cells with synthetic components, have opened a new path in miniaturized systems with the potential to provide actuation and control for systems down to a few microns in size. Here, we address the challenge of remotely controlling bio-hybrid microswimmers propelled by multiple bacterial cells. These devices have been proposed as a viable method for targeted drug delivery but have also been shown to exhibit stochastic motion. We demonstrate a method of remote magnetic control that significantly reduces the stochasticity of the motion, enabling steering control. The demonstrated microswimmers consist of multiple Serratia marcescens (S. marcescens) bacteria attached to a 6 μm-diameter superparamagnetic bead. We characterize their motion and define the parameters governing their controllability. We show that the microswimmers can be controlled along two-dimensional (2-D) trajectories using weak magnetic fields (≤10 mT) and can achieve 2-D swimming speeds up to 7.3 μm s(-1). This magnetic steering approach can be integrated with sensory-based steering in future work, enabling new control strategies for bio-hybrid microsystems.

Do biological-based strategies hold promise to biofouling control in MBRs?

PubMed

Malaeb, Lilian; Le-Clech, Pierre; Vrouwenvelder, Johannes S; Ayoub, George M; Saikaly, Pascal E

2013-10-01

Biofouling in membrane bioreactors (MBRs) remains a primary challenge for their wider application, despite the growing acceptance of MBRs worldwide. Research studies on membrane fouling are extensive in the literature, with more than 200 publications on MBR fouling in the last 3 years; yet, improvements in practice on biofouling control and management have been remarkably slow. Commonly applied cleaning methods are only partially effective and membrane replacement often becomes frequent. The reason for the slow advancement in successful control of biofouling is largely attributed to the complex interactions of involved biological compounds and the lack of representative-for-practice experimental approaches to evaluate potential effective control strategies. Biofouling is driven by microorganisms and their associated extra-cellular polymeric substances (EPS) and microbial products. Microorganisms and their products convene together to form matrices that are commonly treated as a black box in conventional control approaches. Biological-based antifouling strategies seem to be a promising constituent of an effective integrated control approach since they target the essence of biofouling problems. However, biological-based strategies are in their developmental phase and several questions should be addressed to set a roadmap for translating existing and new information into sustainable and effective control techniques. This paper investigates membrane biofouling in MBRs from the microbiological perspective to evaluate the potential of biological-based strategies in offering viable control alternatives. Limitations of available control methods highlight the importance of an integrated anti-fouling approach including biological strategies. Successful development of these strategies requires detailed characterization of microorganisms and EPS through the proper selection of analytical tools and assembly of results. Existing microbiological/EPS studies reveal a number of implications as well as knowledge gaps, warranting future targeted research. Systematic and representative microbiological studies, complementary utilization of molecular and biofilm characterization tools, standardized experimental methods and validation of successful biological-based antifouling strategies for MBR applications are needed. Specifically, in addition, linking these studies to relevant operational conditions in MBRs is an essential step to ultimately develop a better understanding and more effective and directed control strategy for biofouling. Copyright © 2013 Elsevier Ltd. All rights reserved.

Spikes, Local Field Potentials, and Electrocorticogram Characterization during Motor Learning in Rats for Brain Machine Interface Tasks.

PubMed

Marzullo, T C; Dudley, J R; Miller, C R; Trejo, L; Kipke, D R

2005-01-01

Brain machine interface development typically falls into two arenas, invasive extracellular recording and non-invasive electroencephalogram recording methods. The relationship between action potentials and field potentials is not well understood, and investigation of interrelationships may improve design of neuroprosthetic control systems. Rats were trained on a motor learning task whereby they had to insert their noses into an aperture while simultaneously pressing down on levers with their forepaws; spikes, local field potentials (LFPs), and electrocorticograms (ECoGs) over the motor cortex were recorded and characterized. Preliminary results suggest that the LFP activity in lower cortical layers oscillates with the ECoG.

Rapid-Adiabatic Control of Ro-Vibrational Populations in Polyatomic Molecules

NASA Astrophysics Data System (ADS)

Zak, Emil J.; Yachmenev, Andrey

2017-06-01

We present a simple method for control of ro-vibrational populations in polyatomic molecules in the presence of inhomogeneous electric fields [1]. Cooling and trapping of heavy polar polyatomic molecules has become one of the frontier goals in high-resolution molecular spectroscopy, especially in the context of parity violation measurement in chiral compounds [2]. A key step toward reaching this goal would be development of a robust and efficient protocol for control of populations of ro-vibrational states in polyatomic, often floppy molecules. Here we demonstrate a modification of the stark-chirped rapid-adiabatic-passage technique (SCRAP) [3], designed for achieving high levels of control of ro-vibrational populations over a selected region in space. The new method employs inhomogeneous electric fields to generate space- and time- controlled Stark-shifts of energy levels in molecules. Adiabatic passage between ro-vibrational states is enabled by the pump pulse, which raises the value of the Rabi frequency. This Stark-chirped population transfer can be used in manipulation of population differences between high-field-seeking and low-field-seeking states of molecules in the Stark decelerator [4]. Appropriate timing of voltages on electric rods located along the decelerator combined with a single pump laser renders our method as potentially more efficient than traditional Stark decelerator techniques. Simulations for NH_3 show significant improvement in effectiveness of cooling, with respect to the standard 'moving-potential' method [5]. At the same time a high phase-space acceptance of the molecular packet is maintained. E. J. Zak, A. Yachmenev (submitted). C. Medcraft, R. Wolf, M. Schnell, Angew. Chem. Int. Ed., 53, 43, 11656-11659 (2014) M. Oberst, H. Munch, T. Halfman, PRL 99, 173001 (2007). K. Wohlfart, F. Grätz, F. Filsinger, H. Haak, G. Meijer, J. Küpper, Phys. Rev. A 77, 031404(R) (2008). H. L. Bethlem, F. M. H. Crompvoets, R. T. Jongma, S. Y. T. van de Meerakker, G. Meijer, Phys. Rev. A, 65, 053416 (2002).

"We weren't the sort that wanted intimacy every night": Birth control and abstinence in England, c.1930-60.

PubMed

Szreter, Simon; Fisher, Kate

2010-06-10

This article presents an exploration of qualitative evidence on the relationship between birth control and abstinence from an oral history project, which interviewed middle and working-class English men and women, who had married between the late 1920s and the early 1950s. Among the working classes the assumption that men were responsible for birth control choices and the disadvantages that contraceptive methods of all types posed, combined with the fear of pregnancy, acted as a disincentive to have sex and resulted in forms of partial abstinence. Among the middle classes, women had much more access to birth control information and as a consequence a greater range of methods was used, including more female methods. However, the reluctance of couples to discuss sexual matters, and some continued preference for male methods meant that while condoms were the most regularly used middle-class male method, both withdrawal and abstinence were also in evidence. Moreover, although partners were more likely to discuss birth control at the start of their marriages, they were less likely to agree that contraception was a male responsibility and there was greater potential for conflict over contraceptive methods, not infrequently resulting in abstinence. The evidence suggests that sexual and contraceptive practices in marriages in England at the end of the secular fertility decline do not present a picture which straightforwardly correlates with the assumptions represented by the popular thesis that this period of increased fertility control was closely associated with the rise of companionate marriage.

“We weren’t the sort that wanted intimacy every night”: Birth control and abstinence in England, c.1930–60

PubMed Central

Szreter, Simon; Fisher, Kate

2015-01-01

This article presents an exploration of qualitative evidence on the relationship between birth control and abstinence from an oral history project, which interviewed middle and working-class English men and women, who had married between the late 1920s and the early 1950s. Among the working classes the assumption that men were responsible for birth control choices and the disadvantages that contraceptive methods of all types posed, combined with the fear of pregnancy, acted as a disincentive to have sex and resulted in forms of partial abstinence. Among the middle classes, women had much more access to birth control information and as a consequence a greater range of methods was used, including more female methods. However, the reluctance of couples to discuss sexual matters, and some continued preference for male methods meant that while condoms were the most regularly used middle-class male method, both withdrawal and abstinence were also in evidence. Moreover, although partners were more likely to discuss birth control at the start of their marriages, they were less likely to agree that contraception was a male responsibility and there was greater potential for conflict over contraceptive methods, not infrequently resulting in abstinence. The evidence suggests that sexual and contraceptive practices in marriages in England at the end of the secular fertility decline do not present a picture which straightforwardly correlates with the assumptions represented by the popular thesis that this period of increased fertility control was closely associated with the rise of companionate marriage. PMID:25931803

Runaway electron beam control for longitudinally pumped metal vapor lasers

NASA Astrophysics Data System (ADS)

Kolbychev, G. V.; Kolbycheva, P. D.

1995-08-01

Physics and techniques for producing of the pulsed runaway electron beams are considered. The main obstacle for increasing electron energies in the beams is revealed to be a self- breakdown of the e-gun's gas-filled diode. Two methods to suppress the self-breakdown and enhance the volumetric discharge producing the e-beam are offered and examined. Each of them provides 1.5 fold increase of the ceiling potential on the gun. The methods also give the ways to control several guns simultaneously. Resulting in the possibility of realizing the powerful longitudinal pumping of metal-vapor lasers on self-terminated transitions of atoms or ions.

COLD-SAT feasibility study safety analysis

NASA Technical Reports Server (NTRS)

Mchenry, Steven T.; Yost, James M.

1991-01-01

The Cryogenic On-orbit Liquid Depot-Storage, Acquisition, and Transfer (COLD-SAT) satellite presents some unique safety issues. The feasibility study conducted at NASA-Lewis desired a systems safety program that would be involved from the initial design in order to eliminate and/or control the inherent hazards. Because of this, a hazards analysis method was needed that: (1) identified issues that needed to be addressed for a feasibility assessment; and (2) identified all potential hazards that would need to be controlled and/or eliminated during the detailed design phases. The developed analysis method is presented as well as the results generated for the COLD-SAT system.

Impulsivity, Mental Disorder, and Suicide in Rural China

PubMed Central

Lin, Lin; Zhang, Jie

2017-01-01

Aims The purpose of this study was to investigate the relationship among impulsivity, mental disorder, and suicide with a sample of rural young Chinese. Methods Subjects were 392 consecutively recruited male and female suicides aged 15–34 years and 416 community male and female controls of the same age range sampled in rural China. The case-control data were obtained using psychological autopsy method with structured and semi-structured instruments. Results Dysfunctional impulsivity was a significant risk factor regardless of mental disorder in rural China. Conclusions Dysfunctional impulsivity is a potential area for further study of suicidal behavior. The suicide prevention efforts in rural China may address impulsivity. PMID:25764273

Vacuum Powder Injector

NASA Technical Reports Server (NTRS)

Working, Dennis C.

1991-01-01

Method developed to provide uniform impregnation of bundles of carbon-fiber tow with low-solubility, high-melt-flow polymer powder materials to produce composite prepregs. Vacuum powder injector expands bundle of fiber tow, applies polymer to it, then compresses bundle to hold powder. System provides for control of amount of polymer on bundle. Crystallinity of polymer maintained by controlled melt on takeup system. All powder entrapped, and most collected for reuse. Process provides inexpensive and efficient method for making composite materials. Allows for coating of any bundle of fine fibers with powders. Shows high potential for making prepregs of improved materials and for preparation of high-temperature, high-modulus, reinforced thermoplastics.

Methods proposed to achieve air quality standards for mobile sources and technology surveillance.

PubMed Central

Piver, W T

1975-01-01

The methods proposed to meet the 1975 Standards of the Clean Air Act for mobile sources are alternative antiknocks, exhaust emission control devices, and alternative engine designs. Technology surveillance analysis applied to this situation is an attempt to anticipate potential public and environmental health problems from these methods, before they happen. Components of this analysis are exhaust emission characterization, environmental transport and transformation, levels of public and environmental exposure, and the influence of economics on the selection of alternative methods. The purpose of this presentation is to show trends as a result of the interaction of these different components. In no manner can these trends be interpreted explicitly as to what will really happen. Such an analysis is necessary so that public and environmental health officials have the opportunity to act on potential problems before they become manifest. PMID:50944

Evaluating Point of Sale Tobacco Marketing Using Behavioral Laboratory Methods

PubMed Central

Robinson, Jason D.; Drobes, David J.; Brandon, Thomas H.; Wetter, David W.; Cinciripini, Paul M.

2018-01-01

With passage of the 2009 Family Smoking Prevention and Tobacco Control Act, the FDA has authority to regulate tobacco advertising. As bans on traditional advertising venues and promotion of tobacco products have grown, a greater emphasis has been placed on brand exposure and price promotion in displays of products at the point-of-sale (POS). POS marketing seeks to influence attitudes and behavior towards tobacco products using a variety of explicit and implicit messaging approaches. Behavioral laboratory methods have the potential to provide the FDA with a strong scientific base for regulatory actions and a model for testing future manipulations of POS advertisements. We review aspects of POS marketing that potentially influence smoking behavior, including branding, price promotions, health claims, the marketing of emerging tobacco products, and tobacco counter-advertising. We conceptualize how POS marketing potentially influence individual attention, memory, implicit attitudes, and smoking behavior. Finally, we describe specific behavioral laboratory methods that can be adapted to measure the impact of POS marketing on these domains.

Reversible electrochemical modification of the surface of a semiconductor by an atomic-force microscope probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozhukhov, A. S., E-mail: antonkozhukhov@yandex.ru; Sheglov, D. V.; Latyshev, A. V.

A technique for reversible surface modification with an atomic-force-microscope (AFM) probe is suggested. In this method, no significant mechanical or topographic changes occur upon a local variation in the surface potential of a sample under the AFM probe. The method allows a controlled relative change in the ohmic resistance of a channel in a Hall bridge within the range 20–25%.

Wire EDM for Refractory Materials

NASA Technical Reports Server (NTRS)

Zellars, G. R.; Harris, F. E.; Lowell, C. E.; Pollman, W. M.; Rys, V. J.; Wills, R. J.

1982-01-01

In an attempt to reduce fabrication time and costs, Wire Electrical Discharge Machine (Wire EDM) method was investigated as tool for fabricating matched blade roots and disk slots. Eight high-strength nickel-base superalloys were used. Computer-controlled Wire EDM technique provided high quality surfaces with excellent dimensional tolerances. Wire EDM method offers potential for substantial reductions in fabrication costs for "hard to machine" alloys and electrically conductive materials in specific high-precision applications.

Synthesis and humidity sensing analysis of ZnS nanowires

NASA Astrophysics Data System (ADS)

Okur, Salih; Üzar, Neslihan; Tekgüzel, Nesli; Erol, Ayşe; Çetin Arıkan, M.

2012-03-01

ZnS nanowires synthesized by the vapor-liquid-solid (VLS) method and humidity sensing properties of obtained ZnS nanowires were investigated by quartz crystal microbalance (QCM) method and electrical measurements. The synthesized nanowires were exposed to relative humidity (RH) between 22% and 97% under controlled environment. Our experimental results show that ZnS nanowires have a great potential for humidity sensing applications in room temperature operations.

A kernel regression approach to gene-gene interaction detection for case-control studies.

PubMed

Larson, Nicholas B; Schaid, Daniel J

2013-11-01

Gene-gene interactions are increasingly being addressed as a potentially important contributor to the variability of complex traits. Consequently, attentions have moved beyond single locus analysis of association to more complex genetic models. Although several single-marker approaches toward interaction analysis have been developed, such methods suffer from very high testing dimensionality and do not take advantage of existing information, notably the definition of genes as functional units. Here, we propose a comprehensive family of gene-level score tests for identifying genetic elements of disease risk, in particular pairwise gene-gene interactions. Using kernel machine methods, we devise score-based variance component tests under a generalized linear mixed model framework. We conducted simulations based upon coalescent genetic models to evaluate the performance of our approach under a variety of disease models. These simulations indicate that our methods are generally higher powered than alternative gene-level approaches and at worst competitive with exhaustive SNP-level (where SNP is single-nucleotide polymorphism) analyses. Furthermore, we observe that simulated epistatic effects resulted in significant marginal testing results for the involved genes regardless of whether or not true main effects were present. We detail the benefits of our methods and discuss potential genome-wide analysis strategies for gene-gene interaction analysis in a case-control study design. © 2013 WILEY PERIODICALS, INC.

Applications

NASA Astrophysics Data System (ADS)

Stern, Arthur M.

1986-07-01

Economic incentives have spurred numerous applications of genetically engineered organisms in manufacture of pharmaceuticals and industrial chemicals. These successes, involving a variety of methods of genetic manipulation, have dispelled early fears that genetic engineering could not be handled safely, even in the laboratory. Consequently, the potential for applications in the wider environment without physical containment is being considered for agriculture, mining, pollution control, and pest control. These proposed applications range from modest extensions of current plant breeding techniques for new disease-resistant species to radical combinations of organisms (for example, nitrogen-fixing corn plants). These applications raise concerns about potential ecological impacts (see chapter 5), largely because of adverse experiences with both deliberate and inadvertent introductions of nonindigenous species.

Consumer perspectives on a pericoital contraceptive pill in India and Uganda.

PubMed

Cover, Jane K; Drake, Jennifer Kidwell; Kyamwanga, Imelda T; Turyakira, Eleanor; Dargan, Tanya; Kumakech, Edward; Harner-Jay, Claudia

2013-12-01

Studies suggest that women in some countries have adopted emergency contraceptive pills as a routine method of family planning. This practice indicates there may be latent demand for a pericoital contraceptive pill taken only when a woman has sexual intercourse, and labeled and marketed for use as a regular contraceptive method. To understand the appeal and potential market for a pericoital contraceptive pill, 39 focus groups and 23 in-depth interviews were conducted with women and men in Lucknow, Uttar Pradesh, India, and Kampala, Uganda. A total of 281 individuals participated in this qualitative study. In general, women embraced the idea of a female-controlled method that would be easier than taking a daily oral contraceptive pill and that could be taken either before or after sexual intercourse; in Uganda, especially, women approved of the fact that the method could be taken without a partner's knowledge. Although we do not yet know the extent of side effects for this method, women expressed some concerns about the level and nature of potential side effects. The results suggest that a pericoital contraceptive pill would be well-received by consumers in both country settings. If its efficacy and side effects are acceptable, a pericoital contraceptive pill could fill a gap for female-controlled, discreet, coitus-related contraception, particularly among women who do not have sex very frequently.

A realization of sound focused personal audio system using acoustic contrast control.

PubMed

Chang, Ji-Ho; Lee, Chan-Hui; Park, Jin-Young; Kim, Yang-Hann

2009-04-01

A personal audio system that does not use earphone or any wire would have great interest and potential impact on the audio industries. In this study, a line array speaker system is used to localize sound in the listening zone. The contrast control [Choi, J.-W. and Kim, Y.-H. (2002). J. Acoust. Soc. Am. 111, 1695-1700] is applied, which is a method to make acoustically bright zone around the user and acoustically dark zone in other regions by maximizing the ratio of acoustic potential energy density between the bright and the dark zone. This ratio is regarded as acoustic contrast, analogous with what is used for optical devices. For the evaluation of the performance of acoustic contrast control, experiments are performed and the results are compared with those of uncontrolled case and time reversal array.

Conductive polymer nanotube patch for fast and controlled ex vivo transdermal drug delivery.

PubMed

Nguyen, Thao M; Lee, Sebin; Lee, Sang Bok

2014-10-01

To uptake and release hydrophilic model drugs and insulin in a novel conductive polymer (CP) nanotube transdermal patch. The externally controlled transdermal delivery of model drugs and insulin were tested ex vivo and results were compared with CP films. The unique intrinsic properties of CPs provide electrostatic interaction between the model drugs and polymer backbone. When a pulsed potential was applied, the drug delivery release profile mimics that of injection delivery. With a constant potential applied, the release rate constants of the patch system were up to three-times faster than the control (0 V) and released approximately 80% more drug molecules over 24 h. The CP nanotube transdermal patch represents a new and promising drug method, specifically for hydrophilic molecules, which have been a large obstacle for conventional transdermal drug delivery systems.

On-orbit assembly of a team of flexible spacecraft using potential field based method

NASA Astrophysics Data System (ADS)

Chen, Ti; Wen, Hao; Hu, Haiyan; Jin, Dongping

2017-04-01

In this paper, a novel control strategy is developed based on artificial potential field for the on-orbit autonomous assembly of four flexible spacecraft without inter-member collision. Each flexible spacecraft is simplified as a hub-beam model with truncated beam modes in the floating frame of reference and the communication graph among the four spacecraft is assumed to be a ring topology. The four spacecraft are driven to a pre-assembly configuration first and then to the assembly configuration. In order to design the artificial potential field for the first step, each spacecraft is outlined by an ellipse and a virtual leader of circle is introduced. The potential field mainly depends on the attitude error between the flexible spacecraft and its neighbor, the radial Euclidian distance between the ellipse and the circle and the classical Euclidian distance between the centers of the ellipse and the circle. It can be demonstrated that there are no local minima for the potential function and the global minimum is zero. If the function is equal to zero, the solution is not a certain state, but a set. All the states in the set are corresponding to the desired configurations. The Lyapunov analysis guarantees that the four spacecraft asymptotically converge to the target configuration. Moreover, the other potential field is also included to avoid the inter-member collision. In the control design of the second step, only small modification is made for the controller in the first step. Finally, the successful application of the proposed control law to the assembly mission is verified by two case studies.

Effectiveness of public deliberation methods for gathering input on issues in healthcare: Results from a randomized trial.

PubMed

Carman, Kristin L; Mallery, Coretta; Maurer, Maureen; Wang, Grace; Garfinkel, Steve; Yang, Manshu; Gilmore, Dierdre; Windham, Amy; Ginsburg, Marjorie; Sofaer, Shoshanna; Gold, Marthe; Pathak-Sen, Ela; Davies, Todd; Siegel, Joanna; Mangrum, Rikki; Fernandez, Jessica; Richmond, Jennifer; Fishkin, James; Siu Chao, Alice

2015-05-01

Public deliberation elicits informed perspectives on complex issues that are values-laden and lack technical solutions. This Deliberative Methods Demonstration examined the effectiveness of public deliberation for obtaining informed public input regarding the role of medical evidence in U.S. healthcare. We conducted a 5-arm randomized controlled trial, assigning participants to one of four deliberative methods or to a reading materials only (RMO) control group. The four deliberative methods reflected important differences in implementation, including length of the deliberative process and mode of interaction. The project convened 76 groups between August and November 2012 in four U.S. Chicago, IL; Sacramento, CA; Silver Spring, MD; and Durham, NC, capturing a sociodemographically diverse sample with specific attention to ensuring inclusion of Hispanic, African-American, and elderly participants. Of 1774 people recruited, 75% participated: 961 took part in a deliberative method and 377 participants comprised the RMO control group. To assess effectiveness of the deliberative methods overall and of individual methods, we evaluated whether mean pre-post changes on a knowledge and attitude survey were statistically different from the RMO control using ANCOVA. In addition, we calculated mean scores capturing participant views of the impact and value of deliberation. Participating in deliberation increased participants' knowledge of evidence and comparative effectiveness research and shifted participants' attitudes regarding the role of evidence in decision-making. When comparing each deliberative method to the RMO control group, all four deliberative methods resulted in statistically significant change on at least one knowledge or attitude measure. These findings were underscored by self-reports that the experience affected participants' opinions. Public deliberation offers unique potential for those seeking informed input on complex, values-laden topics affecting broad public constituencies. Copyright © 2015 Elsevier Ltd. All rights reserved.

GOM-Face: GKP, EOG, and EMG-based multimodal interface with application to humanoid robot control.

PubMed

Nam, Yunjun; Koo, Bonkon; Cichocki, Andrzej; Choi, Seungjin

2014-02-01

We present a novel human-machine interface, called GOM-Face , and its application to humanoid robot control. The GOM-Face bases its interfacing on three electric potentials measured on the face: 1) glossokinetic potential (GKP), which involves the tongue movement; 2) electrooculogram (EOG), which involves the eye movement; 3) electromyogram, which involves the teeth clenching. Each potential has been individually used for assistive interfacing to provide persons with limb motor disabilities or even complete quadriplegia an alternative communication channel. However, to the best of our knowledge, GOM-Face is the first interface that exploits all these potentials together. We resolved the interference between GKP and EOG by extracting discriminative features from two covariance matrices: a tongue-movement-only data matrix and eye-movement-only data matrix. With the feature extraction method, GOM-Face can detect four kinds of horizontal tongue or eye movements with an accuracy of 86.7% within 2.77 s. We demonstrated the applicability of the GOM-Face to humanoid robot control: users were able to communicate with the robot by selecting from a predefined menu using the eye and tongue movements.

Affective Aspects of Perceived Loss of Control and Potential Implications for Brain-Computer Interfaces.

PubMed

Grissmann, Sebastian; Zander, Thorsten O; Faller, Josef; Brönstrup, Jonas; Kelava, Augustin; Gramann, Klaus; Gerjets, Peter

2017-01-01

Most brain-computer interfaces (BCIs) focus on detecting single aspects of user states (e.g., motor imagery) in the electroencephalogram (EEG) in order to use these aspects as control input for external systems. This communication can be effective, but unaccounted mental processes can interfere with signals used for classification and thereby introduce changes in the signal properties which could potentially impede BCI classification performance. To improve BCI performance, we propose deploying an approach that potentially allows to describe different mental states that could influence BCI performance. To test this approach, we analyzed neural signatures of potential affective states in data collected in a paradigm where the complex user state of perceived loss of control (LOC) was induced. In this article, source localization methods were used to identify brain dynamics with source located outside but affecting the signal of interest originating from the primary motor areas, pointing to interfering processes in the brain during natural human-machine interaction. In particular, we found affective correlates which were related to perceived LOC. We conclude that additional context information about the ongoing user state might help to improve the applicability of BCIs to real-world scenarios.

Affective Aspects of Perceived Loss of Control and Potential Implications for Brain-Computer Interfaces

PubMed Central

Grissmann, Sebastian; Zander, Thorsten O.; Faller, Josef; Brönstrup, Jonas; Kelava, Augustin; Gramann, Klaus; Gerjets, Peter

2017-01-01

Most brain-computer interfaces (BCIs) focus on detecting single aspects of user states (e.g., motor imagery) in the electroencephalogram (EEG) in order to use these aspects as control input for external systems. This communication can be effective, but unaccounted mental processes can interfere with signals used for classification and thereby introduce changes in the signal properties which could potentially impede BCI classification performance. To improve BCI performance, we propose deploying an approach that potentially allows to describe different mental states that could influence BCI performance. To test this approach, we analyzed neural signatures of potential affective states in data collected in a paradigm where the complex user state of perceived loss of control (LOC) was induced. In this article, source localization methods were used to identify brain dynamics with source located outside but affecting the signal of interest originating from the primary motor areas, pointing to interfering processes in the brain during natural human-machine interaction. In particular, we found affective correlates which were related to perceived LOC. We conclude that additional context information about the ongoing user state might help to improve the applicability of BCIs to real-world scenarios. PMID:28769776

Variation in Quarters Dispositions A Force Protection and Readiness Issue Explanations and Control Method

DTIC Science & Technology

1999-08-01

information may be crucial for the early identification of any range of potential health Variation in Quarters Rates 28 threats from food contamination to... GMO Physician 309.89 .0000 Over Family Practice 682.06 .0000 Over Aeromed Physician

All-optical phase modulation in a cavity-polariton Mach–Zehnder interferometer

PubMed Central

Sturm, C.; Tanese, D.; Nguyen, H.S.; Flayac, H.; Galopin, E.; Lemaître, A.; Sagnes, I.; Solnyshkov, D.; Amo, A.; Malpuech, G.; Bloch, J.

2014-01-01

Quantum fluids based on light is a highly developing research field, since they provide a nonlinear platform for developing optical functionalities and quantum simulators. An important issue in this context is the ability to coherently control the properties of the fluid. Here we propose an all-optical approach for controlling the phase of a flow of cavity-polaritons, making use of their strong interactions with localized excitons. Here we illustrate the potential of this method by implementing a compact exciton–polariton interferometer, which output intensity and polarization can be optically controlled. This interferometer is cascadable with already reported polariton devices and is promising for future polaritonic quantum optic experiments. Complex phase patterns could be also engineered using this optical method, providing a key tool to build photonic artificial gauge fields. PMID:24513781

The B-Lynch uterine brace suture, and a bit of this and a bit of that...

PubMed

Karoshi, Mahantesh

2010-03-01

The widespread application of the B-Lynch brace suture to control postpartum hemorrhage has sparked interest in a variety of adjunctive methods, used alone or in combination, to control uterine bleeding. Although the B-Lynch brace suture has been used with good results throughout the world, failures can and do occur in rare instances, especially when the suture is incorrectly placed for use for an inappropriate indication. Four reports of additional methods to control postpartum hemorrhage are published in this issue of IJGO. Three use the B-Lynch brace suture combined with other techniques. The need for additional techniques reminds the reader of the importance of proper suture application for proper indication. Potential reasons for failure of the B-Lynch suture are provided.

Lymphoproliferative and Gamma Interferon Responses to Stress-Regulated Mycobacterium avium subsp. paratuberculosis Recombinant Proteins

PubMed Central

Gurung, Ratna B.; Begg, Douglas J.; Purdie, Auriol C.; de Silva, Kumudika; Bannantine, John P.

2014-01-01

Johne's disease in ruminants is a chronic infection of the intestines caused by Mycobacterium avium subsp. paratuberculosis. An important strategy to control disease is early detection, and a potentially efficient method for early detection is measurement of cell-mediated immune responses developed by the host in response to exposure or infection. One method is to measure lymphoproliferation and cytokine release from the host cells when exposed to the organism or parts of the organism. In this study, 10 recombinant M. avium subsp. paratuberculosis proteins known to be upregulated under in vitro stress conditions were evaluated by examining their ability to evoke memory as a result of exposure by vaccination or oral challenge with live Mycobacterium avium subsp. paratuberculosis. Out of 10 proteins, MAP2698c was found to induce higher cell-mediated immune responses in vaccinated and challenged sheep in comparison to healthy controls. The findings suggest that not all stress-regulated proteins have the diagnostic potential to detect cell-mediated immune responses in ovine paratuberculosis. PMID:24695774

Tissue vascularization through 3D printing: Will technology bring us flow?

PubMed

Paulsen, S J; Miller, J S

2015-05-01

Though in vivo models provide the most physiologically relevant environment for studying tissue function, in vitro studies provide researchers with explicit control over experimental conditions and the potential to develop high throughput testing methods. In recent years, advancements in developmental biology research and imaging techniques have significantly improved our understanding of the processes involved in vascular development. However, the task of recreating the complex, multi-scale vasculature seen in in vivo systems remains elusive. 3D bioprinting offers a potential method to generate controlled vascular networks with hierarchical structure approaching that of in vivo networks. Bioprinting is an interdisciplinary field that relies on advances in 3D printing technology along with advances in imaging and computational modeling, which allow researchers to monitor cellular function and to better understand cellular environment within the printed tissue. As bioprinting technologies improve with regards to resolution, printing speed, available materials, and automation, 3D printing could be used to generate highly controlled vascularized tissues in a high throughput manner for use in regenerative medicine and the development of in vitro tissue models for research in developmental biology and vascular diseases. © 2015 Wiley Periodicals, Inc.

Controlled endolysosomal release of agents by pH-responsive polymer blend particles

PubMed Central

Zhan, Xi; Tran, Kenny K.; Wang, Liguo; Shen, Hong

2015-01-01

Purpose A key step of delivering extracellular agents to its intracellular target is to escape from endosomal/lysosomal compartments, while minimizing the release of digestive enzymes that may compromise cellular functions. In this study, we examined the intracellular distribution of both fluorecent cargoes and enzymes by a particle delivery platform made from the controlled blending of poly (lactic-co-glycolic acid) (PLGA) and a random pH-sensitive copolymer. Methods We utilized both microscopic and biochemical methods to semi-quantitatively assess how the composition of blend particles affects the level of endosomal escape of cargos of various sizes and enzymes into the cytosolic space. Results We demonstrated that these polymeric particles enabled the controlled delivery of cargos into the cytosolic space that was more dependent on the cargo size and less on the composition of blend particles. Blend particles did not induce the rupture of endosomal/lysosomal compartments and released less than 20% of endosomal/lysosomal enzymes. Conclusions This study provides insight into understanding the efficacy and safety of a delivery system for intracellular delivery of biologics and drugs. Blend particles offer a potential platform to target intracellular compartments while potentially minimizing cellular toxicity. PMID:25592550

New Approaches to Minimum-Energy Design of Integer- and Fractional-Order Perfect Control Algorithms

NASA Astrophysics Data System (ADS)

Hunek, Wojciech P.; Wach, Łukasz

2017-10-01

In this paper the new methods concerning the energy-based minimization of the perfect control inputs is presented. For that reason the multivariable integer- and fractional-order models are applied which can be used for describing a various real world processes. Up to now, the classical approaches have been used in forms of minimum-norm/least squares inverses. Notwithstanding, the above-mentioned tool do not guarantee the optimal control corresponding to optimal input energy. Therefore the new class of inversebased methods has been introduced, in particular the new σ- and H-inverse of nonsquare parameter and polynomial matrices. Thus a proposed solution remarkably outperforms the typical ones in systems where the control runs can be understood in terms of different physical quantities, for example heat and mass transfer, electricity etc. A simulation study performed in Matlab/Simulink environment confirms the big potential of the new energy-based approaches.

Supersonic wing and wing-body shape optimization using an adjoint formulation

NASA Technical Reports Server (NTRS)

Reuther, James; Jameson, Antony

1995-01-01

This paper describes the implementation of optimization techniques based on control theory for wing and wing-body design of supersonic configurations. The work represents an extension of our earlier research in which control theory is used to devise a design procedure that significantly reduces the computational cost by employing an adjoint equation. In previous studies it was shown that control theory could be used toeviseransonic design methods for airfoils and wings in which the shape and the surrounding body-fitted mesh are both generated analytically, and the control is the mapping function. The method has also been implemented for both transonic potential flows and transonic flows governed by the Euler equations using an alternative formulation which employs numerically generated grids, so that it can treat more general configurations. Here results are presented for three-dimensional design cases subject to supersonic flows governed by the Euler equation.

Detection and quantification of Plectosphaerella cucumerina, a potential biological control agent of potato cyst nematodes, by using conventional PCR, real-time PCR, selective media, and baiting.

PubMed

Atkins, S D; Clark, I M; Sosnowska, D; Hirsch, P R; Kerry, B R

2003-08-01

Potato cyst nematodes (PCN) are serious pests in commercial potato production, causing yield losses valued at approximately $300 million in the European Community. The nematophagous fungus Plectosphaerella cucumerina has demonstrated its potential as a biological control agent against PCN populations by reducing field populations by up to 60% in trials. The use of biological control agents in the field requires the development of specific techniques to monitor the release, population size, spread or decline, and pathogenicity against its host. A range of methods have therefore been developed to monitor P. cucumerina. A species-specific PCR primer set (PcCF1-PcCR1) was designed that was able to detect the presence of P. cucumerina in soil, root, and nematode samples. PCR was combined with a bait method to identify P. cucumerina from infected nematode eggs, confirming the parasitic ability of the fungus. A selective medium was adapted to isolate the fungus from root and soil samples and was used to quantify the fungus from field sites. A second P. cucumerina-specific primer set (PcRTF1-PcRTR1) and a Taqman probe (PcRTP1) were designed for real-time PCR quantification of the fungus and provided a very sensitive means of detecting the fungus from soil. PCR, bait, and culture methods were combined to investigate the presence and abundance of P. cucumerina from two field sites in the United Kingdom where PCN populations were naturally declining. All methods enabled differences in the activity of P. cucumerina to be detected, and the results demonstrated the importance of using a combination of methods to investigate population size and activity of fungi.

Study of thermal properties of the metastable supersaturated vapor with the integral equation method

NASA Astrophysics Data System (ADS)

Nie, Chu; Geng, Jun; Marlow, W. H.

2008-02-01

Pressure, excess chemical potential, and excess free energy data for different densities of the supersaturated argon vapor at reduced temperatures from 0.7 to 1.2 are obtained by solving the integral equation with perturbation correction to the radial distribution function [F. Lado, Phys. Rev. 135, A1013 (1964)]. For those state points where there is no solution, the integral equation is solved with the interaction between argon atoms modeled by Lennard-Jones potential plus a repulsive potential with one controlling parameter, αexp(-r /σ) and in the end, all the thermal properties are mapped back to the α =0 case. Our pressure data and the spinodal obtained from the current method are compared with a molecular dynamics simulation study [A. Linhart et al., J. Chem. Phys. 122, 144506 (2005)] of the same system.

Components of action potential repolarization in cerebellar parallel fibres.

PubMed

Pekala, Dobromila; Baginskas, Armantas; Szkudlarek, Hanna J; Raastad, Morten

2014-11-15

Repolarization of the presynaptic action potential is essential for transmitter release, excitability and energy expenditure. Little is known about repolarization in thin, unmyelinated axons forming en passant synapses, which represent the most common type of axons in the mammalian brain's grey matter.We used rat cerebellar parallel fibres, an example of typical grey matter axons, to investigate the effects of K(+) channel blockers on repolarization. We show that repolarization is composed of a fast tetraethylammonium (TEA)-sensitive component, determining the width and amplitude of the spike, and a slow margatoxin (MgTX)-sensitive depolarized after-potential (DAP). These two components could be recorded at the granule cell soma as antidromic action potentials and from the axons with a newly developed miniaturized grease-gap method. A considerable proportion of fast repolarization remained in the presence of TEA, MgTX, or both. This residual was abolished by the addition of quinine. The importance of proper control of fast repolarization was demonstrated by somatic recordings of antidromic action potentials. In these experiments, the relatively broad K(+) channel blocker 4-aminopyridine reduced the fast repolarization, resulting in bursts of action potentials forming on top of the DAP. We conclude that repolarization of the action potential in parallel fibres is supported by at least three groups of K(+) channels. Differences in their temporal profiles allow relatively independent control of the spike and the DAP, whereas overlap of their temporal profiles provides robust control of axonal bursting properties.

Considerations for Integrating Women into Closed Occupations in the U.S. Special Operations Forces

DTIC Science & Technology

2015-05-01

effectiveness of integration. Ideally, studies adopting an experimental design (using both test and control groups ) would be preferred, but sample sizes may...data -- a survey of SOF personnel and a series of focus group discussions -- collected by the research team regarding the potential challenges to... controlled positions. This report summarizes our research , analysis, and conclusions. We used a mixed-methods approach. We reviewed the current state of

Theory of the development of alternans in the heart during controlled diastolic interval pacing

NASA Astrophysics Data System (ADS)

Otani, Niels F.

2017-09-01

The beat-to-beat alternation in action potential durations (APDs) in the heart, called APD alternans, has been linked to the development of serious cardiac rhythm disorders, including ventricular tachycardia and fibrillation. The length of the period between action potentials, called the diastolic interval (DI), is a key dynamical variable in the standard theory of alternans development. Thus, methods that control the DI may be useful in preventing dangerous cardiac rhythms. In this study, we examine the dynamics of alternans during controlled-DI pacing using a series of single-cell and one-dimensional (1D) fiber models of alternans dynamics. We find that a model that combines a so-called memory model with a calcium cycling model can reasonably explain two key experimental results: the possibility of alternans during constant-DI pacing and the phase lag of APDs behind DIs during sinusoidal-DI pacing. We also find that these results can be replicated by incorporating the memory model into an amplitude equation description of a 1D fiber. The 1D fiber result is potentially concerning because it seems to suggest that constant-DI control of alternans can only be effective over only a limited region in space.

Major Depressive Disorder and Impulsive Reactivity to Emotion: Toward a Dual Process View of Depression

PubMed Central

Carver, Charles S.; Johnson, Sheri L.; Joormann, Jutta

2012-01-01

Objective Dual process theories of behavior have been used to suggest that vulnerability to depression involves elevated reactivity to emotions. This study tests that idea, examining self-reported reactivity. Design Comparison between persons with at least one lifetime episode of major depressive disorder (lifetime MDD) and those without this diagnosis, controlling for symptoms of alcohol use (a potential externalizing confound) and current symptoms of depression (a potential state-dependent confound). Methods Undergraduates (N = 120) completed a clinical interview to diagnose lifetime MDD and a series of self-reports bearing on diverse aspects of self-control, including reactivity to emotion. Thirty-four were diagnosed with lifetime MDD; 86 did not meet criteria for MDD. The groups were then compared on three factors underlying the scales assessing self-control. Results The MDD group had higher scores than controls on the two factors that reflect impulsive reactivity to diverse emotions, including emotions that are positive in valence. These effects were not explained by associations with either externalizing symptoms or current depressive symptoms. Conclusions Reflexive reactivity to emotions characterizes depression, in addition to some externalizing problems, and it may deserve study as a potential transdiagnostic feature. PMID:23865405

Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

PubMed Central

Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A.; Peterka, Darcy S.; Boyden, Edward S.; Owen, Jonathan S.; Yuste, Rafael; Englund, Dirk

2016-01-01

The negatively charged nitrogen vacancy (NV−) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV− state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials. PMID:27035935

Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential.

PubMed

Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A; Peterka, Darcy S; Boyden, Edward S; Owen, Jonathan S; Yuste, Rafael; Englund, Dirk

2016-04-12

The negatively charged nitrogen vacancy (NV(-)) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV(-) state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

NASA Astrophysics Data System (ADS)

Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A.; Peterka, Darcy S.; Boyden, Edward S.; Owen, Jonathan S.; Yuste, Rafael; Englund, Dirk

2016-04-01

The negatively charged nitrogen vacancy (NV-) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV- state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

Metatranscriptomics and Pyrosequencing Facilitate Discovery of Potential Viral Natural Enemies of the Invasive Caribbean Crazy Ant, Nylanderia pubens

PubMed Central

Valles, Steven M.; Oi, David H.; Yu, Fahong; Tan, Xin-Xing; Buss, Eileen A.

2012-01-01

Background Nylanderia pubens (Forel) is an invasive ant species that in recent years has developed into a serious nuisance problem in the Caribbean and United States. A rapidly expanding range, explosive localized population growth, and control difficulties have elevated this ant to pest status. Professional entomologists and the pest control industry in the United States are urgently trying to understand its biology and develop effective control methods. Currently, no known biological-based control agents are available for use in controlling N. pubens. Methodology and Principal Findings Metagenomics and pyrosequencing techniques were employed to examine the transcriptome of field-collected N. pubens colonies in an effort to identify virus infections with potential to serve as control agents against this pest ant. Pyrosequencing (454-platform) of a non-normalized N. pubens expression library generated 1,306,177 raw sequence reads comprising 450 Mbp. Assembly resulted in generation of 59,017 non-redundant sequences, including 27,348 contigs and 31,669 singlets. BLAST analysis of these non-redundant sequences identified 51 of potential viral origin. Additional analyses winnowed this list of potential viruses to three that appear to replicate in N. pubens. Conclusions Pyrosequencing the transcriptome of field-collected samples of N. pubens has identified at least three sequences that are likely of viral origin and, in which, N. pubens serves as host. In addition, the N. pubens transcriptome provides a genetic resource for the scientific community which is especially important at this early stage of developing a knowledgebase for this new pest. PMID:22384082

Constructing the effect of alternative intervention strategies on historic epidemics.

PubMed

Cook, A R; Gibson, G J; Gottwald, T R; Gilligan, C A

2008-10-06

Data from historical epidemics provide a vital and sometimes under-used resource from which to devise strategies for future control of disease. Previous methods for retrospective analysis of epidemics, in which alternative interventions are compared, do not make full use of the information; by using only partial information on the historical trajectory, augmentation of control may lead to predictions of a paradoxical increase in disease. Here we introduce a novel statistical approach that takes full account of the available information in constructing the effect of alternative intervention strategies in historic epidemics. The key to the method lies in identifying a suitable mapping between the historic and notional outbreaks, under alternative control strategies. We do this by using the Sellke construction as a latent process linking epidemics. We illustrate the application of the method with two examples. First, using temporal data for the common human cold, we show the improvement under the new method in the precision of predictions for different control strategies. Second, we show the generality of the method for retrospective analysis of epidemics by applying it to a spatially extended arboreal epidemic in which we demonstrate the relative effectiveness of host culling strategies that differ in frequency and spatial extent. Some of the inferential and philosophical issues that arise are discussed along with the scope of potential application of the new method.

Aerial cooperative transporting and assembling control using multiple quadrotor-manipulator systems

NASA Astrophysics Data System (ADS)

Qi, Yuhua; Wang, Jianan; Shan, Jiayuan

2018-02-01

In this paper, a fully distributed control scheme for aerial cooperative transporting and assembling is proposed using multiple quadrotor-manipulator systems with each quadrotor equipped with a robotic manipulator. First, the kinematic and dynamic models of a quadrotor with multi-Degree of Freedom (DOF) robotic manipulator are established together using Euler-Lagrange equations. Based on the aggregated dynamic model, the control scheme consisting of position controller, attitude controller and manipulator controller is presented. Regarding cooperative transporting and assembling, multiple quadrotor-manipulator systems should be able to form a desired formation without collision among quadrotors from any initial position. The desired formation is achieved by the distributed position controller and attitude controller, while the collision avoidance is guaranteed by an artificial potential function method. Then, the transporting and assembling tasks request the manipulators to reach the desired angles cooperatively, which is achieved by the distributed manipulator controller. The overall stability of the closed-loop system is proven by a Lyapunov method and Matrosov's theorem. In the end, the proposed control scheme is simplified for the real application and then validated by two formation flying missions of four quadrotors with 2-DOF manipulators.

Investigating the potential use of environmental DNA (eDNA) for genetic monitoring of marine mammals.

PubMed

Foote, Andrew D; Thomsen, Philip Francis; Sveegaard, Signe; Wahlberg, Magnus; Kielgast, Jos; Kyhn, Line A; Salling, Andreas B; Galatius, Anders; Orlando, Ludovic; Gilbert, M Thomas P

2012-01-01

The exploitation of non-invasive samples has been widely used in genetic monitoring of terrestrial species. In aquatic ecosystems, non-invasive samples such as feces, shed hair or skin, are less accessible. However, the use of environmental DNA (eDNA) has recently been shown to be an effective tool for genetic monitoring of species presence in freshwater ecosystems. Detecting species in the marine environment using eDNA potentially offers a greater challenge due to the greater dilution, amount of mixing and salinity compared with most freshwater ecosystems. To determine the potential use of eDNA for genetic monitoring we used specific primers that amplify short mitochondrial DNA sequences to detect the presence of a marine mammal, the harbor porpoise, Phocoena phocoena, in a controlled environment and in natural marine locations. The reliability of the genetic detections was investigated by comparing with detections of harbor porpoise echolocation clicks by static acoustic monitoring devices. While we were able to consistently genetically detect the target species under controlled conditions, the results from natural locations were less consistent and detection by eDNA was less successful than acoustic detections. However, at one site we detected long-finned pilot whale, Globicephala melas, a species rarely sighted in the Baltic. Therefore, with optimization aimed towards processing larger volumes of seawater this method has the potential to compliment current visual and acoustic methods of species detection of marine mammals.

Race, Ethnicity, and Exposure to Alcohol Outlets

PubMed Central

Morrison, Christopher; Gruenewald, Paul J.; Ponicki, William R.

2016-01-01

Objective: Prior studies suggest that Black and Hispanic minority populations are exposed to greater concentrations of alcohol outlets, potentially contributing to health disparities between these populations and the White majority. We tested the alternative hypothesis that urban economic systems cause outlets to concentrate in low-income areas and, controlling for these effects, lower demand among minority populations leads to fewer outlets. Method: Market potential for alcohol sales, a surrogate for demand, was estimated from survey and census data across census block groups for 50 California cities. Hierarchical Bayesian conditional autoregressive Poisson models then estimated relationships between observed geographic distributions of outlets and the market potential for alcohol, income, population size, and racial and ethnic composition. Results: Market potentials were significantly smaller among lower income Black, Hispanic, and Asian populations. Block groups with greater market potential and lower income had greater concentrations of outlets. When we controlled for these effects, the racial and ethnic group composition of block groups was mostly unrelated to outlet concentrations. Conclusions: Health disparities related to exposure to alcohol outlets are primarily driven by distributions of income and population density across neighborhoods. PMID:26751356

Bacillus subtilis based-formulation for the control of postbloom fruit drop of citrus.

PubMed

Klein, Mariana Nadjara; da Silva, Aline Caroline; Kupper, Katia Cristina

2016-12-01

Postbloom fruit drop (PFD) caused by Colletotrichum acutatum affects flowers and causes early fruit drop in all commercial varieties of citrus. Biological control with the isolate ACB-69 of Bacillus subtilis has been considered as a potential method for controlling this disease. This study aimed to develop and optimize a B. subtilis based-formulation with a potential for large-scale applications and evaluate its effect on C. acutatum in vitro and in vivo. Bacillus subtilis based-formulations were developed using different carrier materials, and their ability to control PFD was evaluated. The results of the assays led to the selection of the B. subtilis based-formulation with talc + urea (0.02 %) and talc + ammonium molybdate (1 mM), which inhibited mycelial growth and germination of C. acutatum. Studies with detached citrus flowers showed that the formulations were effective in controlling the pathogen. In field conditions, talc + urea (0.02 %) provided 73 % asymptomatic citrus flowers and 56 % of the average number of effective fruit (ANEF), equating with fungicide treatment. On the contrary, non-treated trees had 8.8 % of asymptomatic citrus flowers and 0.83 % ANEF. The results suggest that B. subtilis based-formulations with talc as the carrier supplemented with a nitrogen source had a high potential for PFD control.

The potentiality of botanicals and their products as an alternative to chemical insecticides to sandflies (Diptera: Psychodidae): a review.

PubMed

Dinesh, Diwakar Singh; Kumari, Seema; Kumar, Vijay; Das, Pradeep

2014-03-01

Use of chemical pesticides is the current method for controlling sandflies. However, resistance is being developed in sandflies against the insecticide of choice that is DDT (dichlorodiphenyl trichloroethane). Botanicals have potential to act as an alternative to chemical insecticides as the crude extracts and active molecules of some plants show insecticidal effect to sandflies. This will lead to safe, easy and environment friendly method for control of sandflies. Therefore, information regarding botanicals acting as alternative to chemical insecticide against sandflies assumes importance in the context of development of resistance to insecticides as well as to prevent environment from contamination. This review deals with some plants and their products having repellent and insecticidal effect to sandflies in India and abroad. Different methods of extraction and their bioassay on sandflies have been emphasized in the text. Various extracts of some plants like Ricinus communis (Euphorbiaceae), Solanum jasminoides (Solanaceae), Bougainvillea glabra (Nyctaginaceae), Capparis spinosa (Capparidaceae), Acalypha fruticosa (Euphorbiaceae) and Tagetes minuta (Asteraceae) had shown repellent/insecticidal effect on sandflies. This review will be useful in conducting the research work to find out botanicals of Indian context having insecticidal effect on sandflies.

Biomimetic Hydrogel Composites for Soil Stabilization and Contaminant Mitigation.

PubMed

Zhao, Zhi; Hamdan, Nasser; Shen, Li; Nan, Hanqing; Almajed, Abdullah; Kavazanjian, Edward; He, Ximin

2016-11-15

We have developed a novel method to synthesize a hyper-branched biomimetic hydrogel network across a soil matrix to improve the mechanical strength of the loose soil and simultaneously mitigate potential contamination due to excessive ammonium. This method successfully yielded a hierarchical structure that possesses the water retention, ion absorption, and soil aggregation capabilities of plant root systems in a chemically controllable manner. Inspired by the robust organic-inorganic composites found in many living organisms, we have combined this hydrogel network with a calcite biomineralization process to stabilize soil. Our experiments demonstrate that poly(acrylic acid) (PAA) can work synergistically with enzyme-induced carbonate precipitation (EICP) to render a versatile, high-performance soil stabilization method. PAA-enhanced EICP provides multiple benefits including lengthening of water supply time, localization of cementation reactions, reduction of harmful byproduct ammonium, and achievement of ultrahigh soil strength. Soil crusts we have obtained can sustain up to 4.8 × 10 3 kPa pressure, a level comparable to cementitious materials. An ammonium removal rate of 96% has also been achieved. These results demonstrate the potential for hydrogel-assisted EICP to provide effective soil improvement and ammonium mitigation for wind erosion control and other applications.

Small UAV Automatic Ground Collision Avoidance System Design Considerations and Flight Test Results

NASA Technical Reports Server (NTRS)

Sorokowski, Paul; Skoog, Mark; Burrows, Scott; Thomas, SaraKatie

2015-01-01

The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center Small Unmanned Aerial Vehicle (SUAV) Automatic Ground Collision Avoidance System (Auto GCAS) project demonstrated several important collision avoidance technologies. First, the SUAV Auto GCAS design included capabilities to take advantage of terrain avoidance maneuvers flying turns to either side as well as straight over terrain. Second, the design also included innovative digital elevation model (DEM) scanning methods. The combination of multi-trajectory options and new scanning methods demonstrated the ability to reduce the nuisance potential of the SUAV while maintaining robust terrain avoidance. Third, the Auto GCAS algorithms were hosted on the processor inside a smartphone, providing a lightweight hardware configuration for use in either the ground control station or on board the test aircraft. Finally, compression of DEM data for the entire Earth and successful hosting of that data on the smartphone was demonstrated. The SUAV Auto GCAS project demonstrated that together these methods and technologies have the potential to dramatically reduce the number of controlled flight into terrain mishaps across a wide range of aviation platforms with similar capabilities including UAVs, general aviation aircraft, helicopters, and model aircraft.

Research Methods in Healthcare Epidemiology and Antimicrobial Stewardship: Use of Administrative and Surveillance Databases.

PubMed

Drees, Marci; Gerber, Jeffrey S; Morgan, Daniel J; Lee, Grace M

2016-11-01

Administrative and surveillance data are used frequently in healthcare epidemiology and antimicrobial stewardship (HE&AS) research because of their wide availability and efficiency. However, data quality issues exist, requiring careful consideration and potential validation of data. This methods paper presents key considerations for using administrative and surveillance data in HE&AS, including types of data available and potential use, data limitations, and the importance of validation. After discussing these issues, we review examples of HE&AS research using administrative data with a focus on scenarios when their use may be advantageous. A checklist is provided to help aid study development in HE&AS using administrative data. Infect Control Hosp Epidemiol 2016;1-10.

Recombinant entomopathogenic agents: a review of biotechnological approaches to pest insect control.

PubMed

Karabörklü, Salih; Azizoglu, Ugur; Azizoglu, Zehra Busra

2017-12-18

Although the use of chemical pesticides has decreased in recent years, it is still a common method of pest control. However, chemical use leads to challenging problems. The harm caused by these chemicals and the length of time that they will remain in the environment is of great concern to the future and safety of humans. Therefore, developing new pest control agents that are safer and environmentally compatible, as well as assuring their widespread use is important. Entomopathogenic agents are microorganisms that play an important role in the biological control of pest insects and are eco-friendly alternatives to chemical control. They consist of viruses (non-cellular organisms), bacteria (prokaryotic organisms), fungi and protists (eukaryotic organisms), and nematodes (multicellular organisms). Genetic modification (recombinant technology) provides potential new methods for developing entomopathogens to manage pests. In this review, we focus on the important roles of recombinant entomopathogens in terms of pest insect control, placing them into perspective with other views to discuss, examine and evaluate the use of entomopathogenic agents in biological control.

Robust Control for The G-Limit Microgravity Vibration Isolation System

NASA Technical Reports Server (NTRS)

Whorton, Mark S.

2004-01-01

Many microgravity science experiments need an active isolation system to provide a sufficiently quiescent acceleration environment. The g-LIMIT vibration isolation system will provide isolation for Microgravity Science Glovebox experiments in the International Space Station. While standard control system technologies have been demonstrated for these applications, modern control methods have the potential for meeting performance requirements while providing robust stability in the presence of parametric uncertainties that are characteristic of microgravity vibration isolation systems. While H2 and H infinity methods are well established, neither provides the levels of attenuation performance and robust stability in a compensator with low order. Mixed H2/mu controllers provide a means for maximizing robust stability for a given level of mean-square nominal performance while directly optimizing for controller order constraints. This paper demonstrates the benefit of mixed norm design from the perspective of robustness to parametric uncertainties and controller order for microgravity vibration isolation. A nominal performance metric analogous to the mu measure for robust stability assessment is also introduced in order to define an acceptable trade space from which different control methodologies can be compared.

Blending of brain-machine interface and vision-guided autonomous robotics improves neuroprosthetic arm performance during grasping.

PubMed

Downey, John E; Weiss, Jeffrey M; Muelling, Katharina; Venkatraman, Arun; Valois, Jean-Sebastien; Hebert, Martial; Bagnell, J Andrew; Schwartz, Andrew B; Collinger, Jennifer L

2016-03-18

Recent studies have shown that brain-machine interfaces (BMIs) offer great potential for restoring upper limb function. However, grasping objects is a complicated task and the signals extracted from the brain may not always be capable of driving these movements reliably. Vision-guided robotic assistance is one possible way to improve BMI performance. We describe a method of shared control where the user controls a prosthetic arm using a BMI and receives assistance with positioning the hand when it approaches an object. Two human subjects with tetraplegia used a robotic arm to complete object transport tasks with and without shared control. The shared control system was designed to provide a balance between BMI-derived intention and computer assistance. An autonomous robotic grasping system identified and tracked objects and defined stable grasp positions for these objects. The system identified when the user intended to interact with an object based on the BMI-controlled movements of the robotic arm. Using shared control, BMI controlled movements and autonomous grasping commands were blended to ensure secure grasps. Both subjects were more successful on object transfer tasks when using shared control compared to BMI control alone. Movements made using shared control were more accurate, more efficient, and less difficult. One participant attempted a task with multiple objects and successfully lifted one of two closely spaced objects in 92 % of trials, demonstrating the potential for users to accurately execute their intention while using shared control. Integration of BMI control with vision-guided robotic assistance led to improved performance on object transfer tasks. Providing assistance while maintaining generalizability will make BMI systems more attractive to potential users. NCT01364480 and NCT01894802 .

Chemical control of ticks on cattle and the resistance of these parasites to acaricides.

PubMed

George, J E; Pound, J M; Davey, R B

2004-01-01

Toward the end of the nineteenth century a complex of problems related to ticks and tick-borne diseases of cattle created a demand for methods to control ticks and reduce losses of cattle. The discovery and use of arsenical solutions in dipping vats for treating cattle to protect them against ticks revolutionized tick and tick-borne disease control programmes. Arsenic dips for cattle were used for about 40 years before the evolution of resistance of ticks to the chemical, and the development and marketing of synthetic organic acaricides after World War II provided superior alternative products. Most of the major groups of organic pesticides are represented on the list of chemicals used to control ticks on cattle. Unfortunately, the successive evolution of resistance of ticks to acaricides in each chemical group with the concomitant reduction in the usefulness of a group of acaricides is a major reason for the diversity of acaricides. Whether a producer chooses a traditional method for treating cattle with an acaricide or uses a new method, he must recognize the benefits, limitations and potential problems with each application method and product. Simulation models and research were the basis of recommendations for tick control strategies advocating approaches that reduced reliance on acaricides. These recommendations for controlling ticks on cattle are in harmony with recommendations for reducing the rate of selection for acaricide resistance. There is a need to transfer knowledge about tick control and resistance mitigation strategies to cattle producers.

Effect of rotation rate on the forces of a rotating cylinder: Simulation and control

NASA Technical Reports Server (NTRS)

Burns, John A.; Ou, Yuh-Roung

1993-01-01

In this paper we present numerical solutions to several optimal control problems for an unsteady viscous flow. The main thrust of this work is devoted to simulation and control of an unsteady flow generated by a circular cylinder undergoing rotary motion. By treating the rotation rate as a control variable, we can formulate two optimal control problems and use a central difference/pseudospectral transform method to numerically compute the optimal control rates. Several types of rotations are considered as potential controls, and we show that a proper synchronization of forcing frequency with the natural vortex shedding frequency can greatly influence the flow. The results here indicate that using moving boundary controls for such systems may provide a feasible mechanism for flow control.

Post-trial follow-up methodology in large randomized controlled trials: a systematic review protocol.

PubMed

Llewellyn-Bennett, Rebecca; Bowman, Louise; Bulbulia, Richard

2016-12-15

Clinical trials typically have a relatively short follow-up period, and may both underestimate potential benefits of treatments investigated, and fail to detect hazards, which can take much longer to emerge. Prolonged follow-up of trial participants after the end of the scheduled trial period can provide important information on both efficacy and safety outcomes. This protocol describes a systematic review to qualitatively compare methods of post-trial follow-up used in large randomized controlled trials. A systematic search of electronic databases and clinical trial registries will use a predefined search strategy. All large (more than 1000 adult participants) randomized controlled trials will be evaluated. Two reviewers will screen and extract data according to this protocol with the aim of 95% concordance of papers checked and discrepancies will be resolved by a third reviewer. Trial methods, participant retention rates and prevalence of missing data will be recorded and compared. The potential for bias will be evaluated using the Cochrane Risk of Bias tool (applied to the methods used during the in-trial period) with the aim of investigating whether the quality of the post-trial follow-up methodology might be predicted by the quality of the methods used for the original trial. Post-trial follow-up can provide valuable information about the long-term benefits and hazards of medical interventions. However, it can be logistically challenging and costly. The aim of this systematic review is to describe how trial participants have been followed-up post-trial in order to inform future post-trial follow-up designs. Not applicable for PROSPERO registration.

The identification and classification of skin irritation hazard by a human patch test.

PubMed

Basketter, D A; Whittle, E; Griffiths, H A; York, M

1994-08-01

There exist various regulatory instruments the purpose of which is to ensure that the intrinsic toxic hazards associated with substances and preparations are identified. In the context of identification of skin irritation potential, the method is normally the Draize test. Guidance notes provided by the OECD and the EEC expect that corrosive substances will have been screened out by a variety of methods. Substances or preparations which cause a sufficient degree of skin irritation will be classified as skin irritants. The primary motivation behind the present work was to introduce the concept that it is possible to assess the hazard potential of a substance or preparation to produce skin irritation in a human study. In the example presented here, 20% sodium lauryl sulfate (SLS) has been chosen as the positive control. With the protocol currently devised, occluded patch treatment with 20% SLS for up to 4 hr produces an irritant response in just over half of the panel. An irritant response is taken as a clinically evident and significant increase in erythema, oedema or dryness--a minimum of a+ reaction on the ICDRG scale. At such a level of response with the positive control (both in terms of intensity and in proportion of the panel), it is then possible to judge and/or to determine statistically, whether the test material has produced a level of skin irritation which is similar to, greater, or lower than the positive control. In this way a human patch test protocol can form a fundamental component of a strategy for the replacement of animals in determination of skin irritation and corrosion potential. By use of a careful and progressive protocol and by comparison of test data against a positive control it is both possible and practical to classify substances and preparations in terms of their skin irritation potential using that endpoint in the species of concern, man.

WE-G-BRA-07: Analyzing the Safety Implications of a Brachytherapy Process Improvement Project Utilizing a Novel System-Theory-Based Hazard-Analysis Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, A; Samost, A; Viswanathan, A

Purpose: To investigate the hazards in cervical-cancer HDR brachytherapy using a novel hazard-analysis technique, System Theoretic Process Analysis (STPA). The applicability and benefit of STPA to the field of radiation oncology is demonstrated. Methods: We analyzed the tandem and ring HDR procedure through observations, discussions with physicists and physicians, and the use of a previously developed process map. Controllers and their respective control actions were identified and arranged into a hierarchical control model of the system, modeling the workflow from applicator insertion through initiating treatment delivery. We then used the STPA process to identify potentially unsafe control actions. Scenarios weremore » then generated from the identified unsafe control actions and used to develop recommendations for system safety constraints. Results: 10 controllers were identified and included in the final model. From these controllers 32 potentially unsafe control actions were identified, leading to more than 120 potential accident scenarios, including both clinical errors (e.g., using outdated imaging studies for planning), and managerial-based incidents (e.g., unsafe equipment, budget, or staffing decisions). Constraints identified from those scenarios include common themes, such as the need for appropriate feedback to give the controllers an adequate mental model to maintain safe boundaries of operations. As an example, one finding was that the likelihood of the potential accident scenario of the applicator breaking during insertion might be reduced by establishing a feedback loop of equipment-usage metrics and equipment-failure reports to the management controller. Conclusion: The utility of STPA in analyzing system hazards in a clinical brachytherapy system was demonstrated. This technique, rooted in system theory, identified scenarios both technical/clinical and managerial in nature. These results suggest that STPA can be successfully used to analyze safety in brachytherapy and may prove to be an alternative to other hazard analysis techniques.« less

An efficient method for computing unsteady transonic aerodynamics of swept wings with control surfaces

NASA Technical Reports Server (NTRS)

Liu, D. D.; Kao, Y. F.; Fung, K. Y.

1989-01-01

A transonic equivalent strip (TES) method was further developed for unsteady flow computations of arbitrary wing planforms. The TES method consists of two consecutive correction steps to a given nonlinear code such as LTRAN2; namely, the chordwise mean flow correction and the spanwise phase correction. The computation procedure requires direct pressure input from other computed or measured data. Otherwise, it does not require airfoil shape or grid generation for given planforms. To validate the computed results, four swept wings of various aspect ratios, including those with control surfaces, are selected as computational examples. Overall trends in unsteady pressures are established with those obtained by XTRAN3S codes, Isogai's full potential code and measured data by NLR and RAE. In comparison with these methods, the TES has achieved considerable saving in computer time and reasonable accuracy which suggests immediate industrial applications.

Controlled assembly of jammed colloidal shells on fluid droplets.

PubMed

Subramaniam, Anand Bala; Abkarian, Manouk; Stone, Howard A

2005-07-01

Assembly of colloidal particles on fluid interfaces is a promising technique for synthesizing two-dimensional microcrystalline materials useful in fields as diverse as biomedicine, materials science, mineral flotation and food processing. Current approaches rely on bulk emulsification methods, require further chemical and thermal treatments, and are restrictive with respect to the materials used. The development of methods that exploit the great potential of interfacial assembly for producing tailored materials have been hampered by the lack of understanding of the assembly process. Here we report a microfluidic method that allows direct visualization and understanding of the dynamics of colloidal crystal growth on curved interfaces. The crystals are periodically ejected to form stable jammed shells, which we refer to as colloidal armour. We propose that the energetic barriers to interfacial crystal growth and organization can be overcome by targeted delivery of colloidal particles through hydrodynamic flows. Our method allows an unprecedented degree of control over armour composition, size and stability.

Controlled assembly of jammed colloidal shells on fluid droplets

NASA Astrophysics Data System (ADS)

Subramaniam, Anand Bala; Abkarian, Manouk; Stone, Howard A.

2005-07-01

Assembly of colloidal particles on fluid interfaces is a promising technique for synthesizing two-dimensional microcrystalline materials useful in fields as diverse as biomedicine, materials science, mineral flotation and food processing. Current approaches rely on bulk emulsification methods, require further chemical and thermal treatments, and are restrictive with respect to the materials used. The development of methods that exploit the great potential of interfacial assembly for producing tailored materials have been hampered by the lack of understanding of the assembly process. Here we report a microfluidic method that allows direct visualization and understanding of the dynamics of colloidal crystal growth on curved interfaces. The crystals are periodically ejected to form stable jammed shells, which we refer to as colloidal armour. We propose that the energetic barriers to interfacial crystal growth and organization can be overcome by targeted delivery of colloidal particles through hydrodynamic flows. Our method allows an unprecedented degree of control over armour composition, size and stability.

Optical Sensor/Actuator Locations for Active Structural Acoustic Control

NASA Technical Reports Server (NTRS)

Padula, Sharon L.; Palumbo, Daniel L.; Kincaid, Rex K.

1998-01-01

Researchers at NASA Langley Research Center have extensive experience using active structural acoustic control (ASAC) for aircraft interior noise reduction. One aspect of ASAC involves the selection of optimum locations for microphone sensors and force actuators. This paper explains the importance of sensor/actuator selection, reviews optimization techniques, and summarizes experimental and numerical results. Three combinatorial optimization problems are described. Two involve the determination of the number and position of piezoelectric actuators, and the other involves the determination of the number and location of the sensors. For each case, a solution method is suggested, and typical results are examined. The first case, a simplified problem with simulated data, is used to illustrate the method. The second and third cases are more representative of the potential of the method and use measured data. The three case studies and laboratory test results establish the usefulness of the numerical methods.

Comparison of Address-based Sampling and Random-digit Dialing Methods for Recruiting Young Men as Controls in a Case-Control Study of Testicular Cancer Susceptibility

PubMed Central

Clagett, Bartholt; Nathanson, Katherine L.; Ciosek, Stephanie L.; McDermoth, Monique; Vaughn, David J.; Mitra, Nandita; Weiss, Andrew; Martonik, Rachel; Kanetsky, Peter A.

2013-01-01

Random-digit dialing (RDD) using landline telephone numbers is the historical gold standard for control recruitment in population-based epidemiologic research. However, increasing cell-phone usage and diminishing response rates suggest that the effectiveness of RDD in recruiting a random sample of the general population, particularly for younger target populations, is decreasing. In this study, we compared landline RDD with alternative methods of control recruitment, including RDD using cell-phone numbers and address-based sampling (ABS), to recruit primarily white men aged 18–55 years into a study of testicular cancer susceptibility conducted in the Philadelphia, Pennsylvania, metropolitan area between 2009 and 2012. With few exceptions, eligible and enrolled controls recruited by means of RDD and ABS were similar with regard to characteristics for which data were collected on the screening survey. While we find ABS to be a comparably effective method of recruiting young males compared with landline RDD, we acknowledge the potential impact that selection bias may have had on our results because of poor overall response rates, which ranged from 11.4% for landline RDD to 1.7% for ABS. PMID:24008901

Ionomic screening of field-grown soybeans identifies mutants with altered seed elemental composition

USDA-ARS?s Scientific Manuscript database

Soybean seeds contain high levels of mineral nutrients essential for human and animal nutrition. High throughput elemental profiling (ionomics) has identified mutants in model plant species grown in controlled environments. Here, we describe a method for identifying potential soybean ionomics mutant...

The Computer in Performance and Instruction: Or, How to Tell the True Color of a Chameleon.

ERIC Educational Resources Information Center

Davis, Richard

1979-01-01

Discusses such potential uses for the computer in employee training programs as management support for training and performance, training project control, improved design and development methods, training program implementation and delivery, and program evaluation, revision, and maintenance. (JEG)

Genotypic variation in traits controlling carbon flux responses to precipitation in switchgrass

USDA-ARS?s Scientific Manuscript database

Background/Questions/Methods Fluxes of carbon in terrestrial ecosystems are key indicators of their productivity and carbon storage potential. Ecosystem fluxes will be impacted by climate change, especially changes in rainfall amount. Fluxes may also be affected by plant traits, including abovegr...

What food and feeding rates are optimum for the Chironomus dilutus sediment toxicity test method?

EPA Science Inventory

Laboratory tests with benthic macroinvertebrates conducted using standard toxicity test procedures are used to assess the potential toxicity of contaminated sediments. Results are compared across sites or for batches of samples, and the performance of organisms in control treatme...

EVALUATION OF GEOPHYSICAL METHODS FOR THE DETECTION OF SUBSURFACE TETRACHLOROETHYLENE IN CONTROLLED SPILL EXPERIMENTS

EPA Science Inventory

This paper presents some of the results of five of the techniques: cross borehole complex resistivity (CR) also referred to as spectral induced polarization (SIP), cross borehole high resolution seismic (HRS), borehole self potential (SP), surface ground penetration radar (GPR), ...

An EST database of the Caribbean fruit fly, Anastrephas suspensa (Diptera:Tephritidae)

USDA-ARS?s Scientific Manuscript database

The ability to create transgenic strains of economically and medically important insect species has the potential to greatly improve existing biological control methods, which is a major goal of our laboratory at the Center for Medical, Agricultural and Veterinary Entomology, USDA, Agricultural Rese...

Characterizing a novel strain of Bacillus amyloliquefaciens BAC03 for potential biological control application

USDA-ARS?s Scientific Manuscript database

Aims: Identify and characterize a bacterial strain from suppressive soil, BAC03, evaluate its antimicrobial activity against Streptomyces scabies and other microorganisms, and characterize an antimicrobial substance produced by this strain. Methods and Results: Bacterial strain BAC03 (isolated from ...

Tunable thermal expansion in framework materials through redox intercalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jun; Gao, Qilong; Sanson, Andrea

Thermal expansion properties of solids are of fundamental interest and control of thermal expansion is important for practical applications but can be difficult to achieve. Many framework type materials show negative thermal expansion when internal cages are empty but positive thermal expansion when additional atoms or molecules fill internal voids present, offering a potential route for control. Here we show that redox intercalation offers an effective method to control thermal expansion from positive to zero to negative by insertion of Li ions into the simple negative thermal expansion framework material ScF 3, doped with 10% Fe to enable reduction. Themore » small concentration of intercalated Li ions has a strong influence through steric hindrance of transverse fluoride ion vibrations, which directly controls the thermal expansion. As a result, redox intercalation of guest ions is thus likely to be a general and effective method for controlling thermal expansion in the many known framework materials with phonon-driven negative thermal expansion.« less

Modelling malaria control by introduction of larvivorous fish.

PubMed

Lou, Yijun; Zhao, Xiao-Qiang

2011-10-01

Malaria creates serious health and economic problems which call for integrated management strategies to disrupt interactions among mosquitoes, the parasite and humans. In order to reduce the intensity of malaria transmission, malaria vector control may be implemented to protect individuals against infective mosquito bites. As a sustainable larval control method, the use of larvivorous fish is promoted in some circumstances. To evaluate the potential impacts of this biological control measure on malaria transmission, we propose and investigate a mathematical model describing the linked dynamics between the host-vector interaction and the predator-prey interaction. The model, which consists of five ordinary differential equations, is rigorously analysed via theories and methods of dynamical systems. We derive four biologically plausible and insightful quantities (reproduction numbers) that completely determine the community composition. Our results suggest that the introduction of larvivorous fish can, in principle, have important consequences for malaria dynamics, but also indicate that this would require strong predators on larval mosquitoes. Integrated strategies of malaria control are analysed to demonstrate the biological application of our developed theory.

Tunable thermal expansion in framework materials through redox intercalation

DOE PAGES

Chen, Jun; Gao, Qilong; Sanson, Andrea; ...

2017-02-09

Thermal expansion properties of solids are of fundamental interest and control of thermal expansion is important for practical applications but can be difficult to achieve. Many framework type materials show negative thermal expansion when internal cages are empty but positive thermal expansion when additional atoms or molecules fill internal voids present, offering a potential route for control. Here we show that redox intercalation offers an effective method to control thermal expansion from positive to zero to negative by insertion of Li ions into the simple negative thermal expansion framework material ScF 3, doped with 10% Fe to enable reduction. Themore » small concentration of intercalated Li ions has a strong influence through steric hindrance of transverse fluoride ion vibrations, which directly controls the thermal expansion. As a result, redox intercalation of guest ions is thus likely to be a general and effective method for controlling thermal expansion in the many known framework materials with phonon-driven negative thermal expansion.« less

Conditioning of Model Identification Task in Immune Inspired Optimizer SILO

NASA Astrophysics Data System (ADS)

Wojdan, K.; Swirski, K.; Warchol, M.; Maciorowski, M.

2009-10-01

Methods which provide good conditioning of model identification task in immune inspired, steady-state controller SILO (Stochastic Immune Layer Optimizer) are presented in this paper. These methods are implemented in a model based optimization algorithm. The first method uses a safe model to assure that gains of the process's model can be estimated. The second method is responsible for elimination of potential linear dependences between columns of observation matrix. Moreover new results from one of SILO implementation in polish power plant are presented. They confirm high efficiency of the presented solution in solving technical problems.

Small Unmanned Aircraft Electromagnetic Interference (EMI) Initial Assessment

NASA Technical Reports Server (NTRS)

Jung, Jaewoo; Ippolito, Corey; Rogers, Christopher; Kerczewski, Robert; Downey, Alan; Matheou, Konstantin

2018-01-01

With many applications envisioned for small Unmanned Aircraft Systems (sUAS), and potentially millions of sUAS expected to be in operation in the future, the electromagnetic interference environment associated with the sUAS is of interest to understanding the potential performance impacts on the sUAS command and control communications link as well as the sUAS payload and payload links. As part of NASA's UAS Traffic Management (UTM) Project, flight experiments are planned to characterize the RF environment at altitudes up to 400 ft to better understand how UTM command and control links can be expected to perform. The flight experiments will use an RF channel sensing payload attached to an sUAS. In terms of the payload being capable of measuring relatively low level signals at altitude, electromagnetic interference (EMI) emanating from the sUAS vehicle itself could potentially complicate the measurement process. For this reason, NASA was interested in measuring the EMI performance of the sUAS planned for these flight experiments, a DJI model S1000. The S1000 was thus measured in a controlled EMI test chamber at the NASA Ames Research Center. The S1000 is a carbon fiber based platform with eight rotors. As such, the EMI test results represent potential performance of a number of similar sUAS types. sUAS platforms significantly different from the S1000 may also require EMI testing, and the method employed for NASA's S1000 EMI tests can be applied to other platforms. In this paper we describe the UTM project, the RF channel sensing payload, the EMI testing method and EMI test results for the S1000, and discuss the implications of these results.

Small Unmanned Aircraft Electromagnetic Interference (EMI) Initial Assessment

NASA Technical Reports Server (NTRS)

Jung, Jaewoo; Ippolito, Corey; Rogers, Christopher; Kerczewski, Robert; Downey, Alan; Matheou, Konstantin

2018-01-01

With many applications envisioned for small Unmanned Aircraft Systems (sUAS), and potentially millions of sUAS expected to be in operation in the future, the electromagnetic interference environment associated with the sUAS is of interest to understanding the potential performance impacts on the sUAS command and control communications link as well as the sUAS payload and payload links. As part of NASAâ€"TM"s UAS Traffic Management (UTM) Project, flight experiments are planned to characterize the RF environment at altitudes up to 400 ft to better understand how UTM command and control links can be expected to perform. The flight experiments will use an RF channel sensing payload attached to an sUAS. In terms of the payload being capable of measuring relatively low level signals at altitude, electromagnetic interference (EMI) emanating from the sUAS vehicle itself could potentially complicate the measurement process. For this reason, NASA was interested in measuring the EMI performance of the sUAS planned for these flight experiments, a DJI model S1000. The S1000 was thus measured in a controlled EMI test chamber at the NASA Ames Research Center. The S1000 is a carbon fiber based platform with eight rotors. As such, the EMI test results represent potential performance of a number of similar sUAS types. sUAS platforms significantly different from the S1000 may also require EMI testing, and the method employed for NASAâ€"TM"s S1000 EMI tests can be applied to other platforms. In this paper we describe the UTM project, the RF channel sensing payload, the EMI testing method and EMI test results for the S1000, and discuss the implications of these results.

Advantages and limitations of the Five Domains model for assessing welfare impacts associated with vertebrate pest control.

PubMed

Beausoleil, N J; Mellor, D J

2015-01-01

Many pest control activities have the potential to impact negatively on the welfare of animals, and animal welfare is an important consideration in the development, implementation and evaluation of ethically defensible vertebrate pest control. Thus, reliable and accurate methods for assessing welfare impacts are required. The Five Domains model provides a systematic method for identifying potential or actual welfare impacts associated with an event or situation in four physical or functional domains (nutrition, environment, health or functional status, behaviour) and one mental domain (overall mental or affective state). Here we evaluate the advantages and limitations of the Five Domains model for this purpose and illustrate them using specific examples from a recent assessment of the welfare impacts of poisons used to lethally control possums in New Zealand. The model has a number of advantages which include the following: the systematic identification of a wide range of impacts associated with a variety of control tools; the production of relative rankings of tools in terms of their welfare impacts; the easy incorporation of new information into assessments; and the highlighting of additional information needed. For example, a recent analysis of sodium fluoroacetate (1080) poisoning in possums revealed the need for more information on the period from the onset of clinical signs to the point at which consciousness is lost, as well as on the level of consciousness during or after the occurrence of muscle spasms and seizures. The model is also valuable because it clearly separates physical or functional and affective impacts, encourages more comprehensive consideration of negative affective experiences than has occurred in the past, and allows development and evaluation of targeted mitigation strategies. Caution must be used in interpreting and applying the outputs of the model, most importantly because relative rankings or grades are fundamentally qualitative in nature. Certain domains are more useful for evaluating impacts associated with slower/longer-acting tools than for faster-acting methods, and it may be easier to identify impacts in some domains than others. Overall, we conclude that the Five Domains model advances evaluation of the animal welfare impacts of vertebrate pest control methods, provided users are cognisant of its limitations.

Association between depression and glycemic control among type 2 diabetes patients in Lima, Peru

PubMed Central

Crispín‐Trebejo, Brenda; Bernabé‐Ortiz, Antonio

2015-01-01

Abstract Introduction There is limited and controversial information regarding the potential impact of depression on glycemic control. This study aims to evaluate the association between depression and poor glycemic control. In addition, the prevalence of depression and rates of poor glycemic control were determined. Methods Cross‐sectional study performed in the endocrinology unit of two hospitals of ESSALUD in Peru. The outcome of interest was poor glycemic control, evaluated by glycated hemoglobin (HbA1c: < 7% versus ≥ 7%), whereas the exposure of interest was depression defined as 15 or more points in the Patient Health Questionnaire‐9 tool. The association of interest was evaluated using Poisson regression models with robust standard errors reporting prevalence ratios (PR) and 95% confidence intervals (95% CI) adjusting for potential confounders. Results A total of 277 participants, 184 (66.4%) males, mean age 59.0 (SD: 4.8), and 7.1 (SD: 6.8) years of disease were analyzed. Only 31 participants (11.2%; 95% CI: 7.5%–14.9%) had moderately severe or severe depression, whereas 70 (25.3%; 95% CI 20.3%–30.8%) had good glycemic control. Depression increased the probability of having poor glycemic control (PR = 1.32; 95% CI 1.15–1.51) after adjusting for several potential confounders. Conclusions There is an association between depression and poor glycemic control among type 2 diabetes patients. Our results suggest that early detection of depression might be important to facilitate appropriate glycemic control and avoid further metabolic complications. PMID:26037488

Double-cross hydrostatic pressure sample injection for chip CE: variable sample plug volume and minimum number of electrodes.

PubMed

Luo, Yong; Wu, Dapeng; Zeng, Shaojiang; Gai, Hongwei; Long, Zhicheng; Shen, Zheng; Dai, Zhongpeng; Qin, Jianhua; Lin, Bingcheng

2006-09-01

A novel sample injection method for chip CE was presented. This injection method uses hydrostatic pressure, generated by emptying the sample waste reservoir, for sample loading and electrokinetic force for dispensing. The injection was performed on a double-cross microchip. One cross, created by the sample and separation channels, is used for formation of a sample plug. Another cross, formed by the sample and controlling channels, is used for plug control. By varying the electric field in the controlling channel, the sample plug volume can be linearly adjusted. Hydrostatic pressure takes advantage of its ease of generation on a microfluidic chip, without any electrode or external pressure pump, thus allowing a sample injection with a minimum number of electrodes. The potential of this injection method was demonstrated by a four-separation-channel chip CE system. In this system, parallel sample separation can be achieved with only two electrodes, which is otherwise impossible with conventional injection methods. Hydrostatic pressure maintains the sample composition during the sample loading, allowing the injection to be free of injection bias.

Controlling effect of geometrically defined local structural changes on chaotic Hamiltonian systems.

PubMed

Ben Zion, Yossi; Horwitz, Lawrence

2010-04-01

An effective characterization of chaotic conservative Hamiltonian systems in terms of the curvature associated with a Riemannian metric tensor derived from the structure of the Hamiltonian has been extended to a wide class of potential models of standard form through definition of a conformal metric. The geodesic equations reproduce the Hamilton equations of the original potential model through an inverse map in the tangent space. The second covariant derivative of the geodesic deviation in this space generates a dynamical curvature, resulting in (energy-dependent) criteria for unstable behavior different from the usual Lyapunov criteria. We show here that this criterion can be constructively used to modify locally the potential of a chaotic Hamiltonian model in such a way that stable motion is achieved. Since our criterion for instability is local in coordinate space, these results provide a minimal method for achieving control of a chaotic system.

Spatial Brain Control Interface using Optical and Electrophysiological Measures

DTIC Science & Technology

2013-08-27

appropriate for implementing a reliable brain-computer interface ( BCI ). The LSVM method 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 27-08-2013 13...Machine (LSVM) was the most appropriate for implementing a reliable brain-computer interface ( BCI ). The LSVM method was applied to the imaging data...local field potentials proved to be fast and strongly tuned for the spatial parameters of the task. Thus, a reliable BCI that can predict upcoming

On the potential of redox potential measurements for the characterization of greenhouse gas emissions - preliminary results

NASA Astrophysics Data System (ADS)

Wang, Jihuan; Bogena, Heye; Brüggemann, Nicolas

2017-04-01

Soil greenhouse gas (GHG) emissions contribute to global warming. In order to support mitigation measures against global warming it is important to understand the controlling processes of GHG emissions. Previous studies focused mainly on the paddy rice fields or wetlands showed a strong relationship between soil redox potential and GHG emission (e.g. N2O). Recent sensor developments open the possibility for the long-term monitoring of field scale soil redox potential changes. Here, we performed laboratory lysimeter experiments to investigate how changes in the redox potential, induced by changes in the water level, affect GHG emissions from agricultural soil. Under our experimental conditions, we found that N2O emissions followed closely the changes in redox potential. The dynamics of redox potential were induced by changing the water-table depth in a laboratory lysimeter. During saturated conditions we found a clear negative correlation between redox potentials and N2O emission rates N2O. After switching from saturated to unsaturated conditions, N2O emission quickly decreased. In contrast, the emissions of CO2 increased with increasing soil redox potentials. The level of N2O emission also depended on the fertilization level of the soil. We propose that redox potential measurements are a viable method for better understanding of the controlling factors of GHG emission and the development agricultural management practices to reduce such emissions.

Determination of the Geometric Form of a Plane of a Tectonic Gap as the Inverse III-posed Problem of Mathematical Physics

NASA Astrophysics Data System (ADS)

Sirota, Dmitry; Ivanov, Vadim

2017-11-01

Any mining operations influence stability of natural and technogenic massifs are the reason of emergence of the sources of differences of mechanical tension. These sources generate a quasistationary electric field with a Newtonian potential. The paper reviews the method of determining the shape and size of a flat source field with this kind of potential. This common problem meets in many fields of mining: geological exploration mineral resources, ore deposits, control of mining by underground method, determining coal self-heating source, localization of the rock crack's sources and other applied problems of practical physics. This problems are ill-posed and inverse and solved by converting to Fredholm-Uryson integral equation of the first kind. This equation will be solved by A.N. Tikhonov regularization method.

Generating size-controlled embryoid bodies using laser direct-write.

PubMed

Dias, A D; Unser, A M; Xie, Y; Chrisey, D B; Corr, D T

2014-06-01

Embryonic stem cells (ESCs) have the potential to self-renew and differentiate into any specialized cell type. One common method to differentiate ESCs in vitro is through embryoid bodies (EBs), three-dimensional cellular aggregates that spontaneously self-assemble and generally express markers for the three germ layers, endoderm, ectoderm, and mesoderm. It has been previously shown that both EB size and 2D colony size each influence differentiation. We hypothesized that we could control the size of the EB formed by mouse ESCs (mESCs) by using a cell printing method, laser direct-write (LDW), to control both the size of the initial printed colony and the local cell density in printed colonies. After printing mESCs at various printed colony sizes and printing densities, two-way ANOVAs indicated that the EB diameter was influenced by printing density after three days (p = 0.0002), while there was no effect of the printed colony diameter on the EB diameter at the same timepoint (p = 0.74). There was no significant interaction between these two factors. Tukey's honestly significant difference test showed that high-density colonies formed significantly larger EBs, suggesting that printed mESCs quickly aggregate with nearby cells. Thus, EBs can be engineered to a desired size by controlling printing density, which will influence the design of future differentiation studies. Herein, we highlight the capacity of LDW to control the local cell density and colony size independently, at prescribed spatial locations, potentially leading to better stem cell maintenance and directed differentiation.

Development of MCAERO wing design panel method with interactive graphics module

NASA Technical Reports Server (NTRS)

Hawk, J. D.; Bristow, D. R.

1984-01-01

A reliable and efficient iterative method has been developed for designing wing section contours corresponding to a prescribed subcritical pressure distribution. The design process is initialized by using MCAERO (MCAIR 3-D Subsonic Potential Flow Analysis Code) to analyze a baseline configuration. A second program DMCAERO is then used to calculate a matrix containing the partial derivative of potential at each control point with respect to each unknown geometry parameter by applying a first-order expansion to the baseline equations in MCAERO. This matrix is calculated only once but is used in each iteration cycle to calculate the geometry perturbation and to analyze the perturbed geometry. The potential on the new geometry is calculated by linear extrapolation from the baseline solution. This extrapolated potential is converted to velocity by numerical differentiation, and velocity is converted to pressure by using Bernoulli's equation. There is an interactive graphics option which allows the user to graphically display the results of the design process and to interactively change either the geometry or the prescribed pressure distribution.

Pattern Recognition Control Design

NASA Technical Reports Server (NTRS)

Gambone, Elisabeth A.

2018-01-01

Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.

Controlling measures of micro-plastic and nano pollutants: A short review of disposing waste toners.

PubMed

Ruan, Jujun; Qin, Baojia; Huang, Jiaxin

2018-05-31

Micro-plastic and nano-particle have been the focal pollutants in environmental science. The printer toner is omitted micro-plastic and nano pollutant. It is comprised of micro polyacrylate styrene and nano-Fe 3 O 4 particles. Polyacrylate styrene and nano-metal were proved to be irreversibly toxic to biological cells. Therefore, toners have the potential environmental risk and healthy harm due to include micro plastics and nano-metal. To our knowledge, few studies provided the specific collection and treatment of micro-plastic pollutant. This paper has chosen a kind of micro-plastic and nano pollutant toxic toner and provided technical guidance and inspiration for controlling the micro-plastic and nano pollutants. The method of vacuum-gasification-condensation was adopted for controlling the micro-plastic and nano pollutant toner. We believe this review will open up a potential avenue for controlling micro-plastic and nano pollutants for environmental protection. Copyright © 2018 Elsevier Ltd. All rights reserved.

Confinement control mechanism for two-electron Hulthen quantum dots in plasmas

NASA Astrophysics Data System (ADS)

Bahar, M. K.; Soylu, A.

2018-05-01

In this study, for the first time, the energies of two-electron Hulthen quantum dots (TEHQdots) embedded in Debye and quantum plasmas modeled by the more general exponential cosine screened Coulomb (MGECSC) potential under the combined influence of electric and magnetic fields are investigated by numerically solving the Schrödinger equation using the asymptotic iteration method. To do this, the four different forms of the MGECSC potential, which set through the different cases of the potential parameters, are taken into consideration. We propose that plasma environments form considerable quantum mechanical effects for quantum dots and other atomic systems and that plasmas are important experimental arguments. In this study, by considering the quantum dot parameters, the external field parameters, and the plasma screening parameters, a control mechanism of the confinement on energies of TEHQdots and the frequency of the radiation emitted by TEHQdots as a result of any excitation is discussed. In this mechanism, the behaviors, similarities, the functionalities of the control parameters, and the influences of plasmas on these quantities are explored.

The Development of DNA Based Methods for the Reliable and Efficient Identification of Nicotiana tabacum in Tobacco and Its Derived Products

PubMed Central

Fan, Wei; Li, Rong; Li, Sifan; Ping, Wenli; Li, Shujun; Naumova, Alexandra; Peelen, Tamara; Yuan, Zheng; Zhang, Dabing

2016-01-01

Reliable methods are needed to detect the presence of tobacco components in tobacco products to effectively control smuggling and classify tariff and excise in tobacco industry to control illegal tobacco trade. In this study, two sensitive and specific DNA based methods, one quantitative real-time PCR (qPCR) assay and the other loop-mediated isothermal amplification (LAMP) assay, were developed for the reliable and efficient detection of the presence of tobacco (Nicotiana tabacum) in various tobacco samples and commodities. Both assays targeted the same sequence of the uridine 5′-monophosphate synthase (UMPS), and their specificities and sensitivities were determined with various plant materials. Both qPCR and LAMP methods were reliable and accurate in the rapid detection of tobacco components in various practical samples, including customs samples, reconstituted tobacco samples, and locally purchased cigarettes, showing high potential for their application in tobacco identification, particularly in the special cases where the morphology or chemical compositions of tobacco have been disrupted. Therefore, combining both methods would facilitate not only the detection of tobacco smuggling control, but also the detection of tariff classification and of excise. PMID:27635142

Advanced scanning probe lithography.

PubMed

Garcia, Ricardo; Knoll, Armin W; Riedo, Elisa

2014-08-01

The nanoscale control afforded by scanning probe microscopes has prompted the development of a wide variety of scanning-probe-based patterning methods. Some of these methods have demonstrated a high degree of robustness and patterning capabilities that are unmatched by other lithographic techniques. However, the limited throughput of scanning probe lithography has prevented its exploitation in technological applications. Here, we review the fundamentals of scanning probe lithography and its use in materials science and nanotechnology. We focus on robust methods, such as those based on thermal effects, chemical reactions and voltage-induced processes, that demonstrate a potential for applications.

Application of active electrode compensation to perform continuous voltage-clamp recordings with sharp microelectrodes.

PubMed

Gómez-González, J F; Destexhe, A; Bal, T

2014-10-01

Electrophysiological recordings of single neurons in brain tissues are very common in neuroscience. Glass microelectrodes filled with an electrolyte are used to impale the cell membrane in order to record the membrane potential or to inject current. Their high resistance induces a high voltage drop when passing current and it is essential to correct the voltage measurements. In particular, for voltage clamping, the traditional alternatives are two-electrode voltage-clamp technique or discontinuous single electrode voltage-clamp (dSEVC). Nevertheless, it is generally difficult to impale two electrodes in a same neuron and the switching frequency is limited to low frequencies in the case of dSEVC. We present a novel fully computer-implemented alternative to perform continuous voltage-clamp recordings with a single sharp-electrode. To reach such voltage-clamp recordings, we combine an active electrode compensation algorithm (AEC) with a digital controller (AECVC). We applied two types of control-systems: a linear controller (proportional plus integrative controller) and a model-based controller (optimal control). We compared the performance of the two methods to dSEVC using a dynamic model cell and experiments in brain slices. The AECVC method provides an entirely digital method to perform continuous recording and smooth switching between voltage-clamp, current clamp or dynamic-clamp configurations without introducing artifacts.

Funnel plot control limits to identify poorly performing healthcare providers when there is uncertainty in the value of the benchmark.

PubMed

Manktelow, Bradley N; Seaton, Sarah E; Evans, T Alun

2016-12-01

There is an increasing use of statistical methods, such as funnel plots, to identify poorly performing healthcare providers. Funnel plots comprise the construction of control limits around a benchmark and providers with outcomes falling outside the limits are investigated as potential outliers. The benchmark is usually estimated from observed data but uncertainty in this estimate is usually ignored when constructing control limits. In this paper, the use of funnel plots in the presence of uncertainty in the value of the benchmark is reviewed for outcomes from a Binomial distribution. Two methods to derive the control limits are shown: (i) prediction intervals; (ii) tolerance intervals Tolerance intervals formally include the uncertainty in the value of the benchmark while prediction intervals do not. The probability properties of 95% control limits derived using each method were investigated through hypothesised scenarios. Neither prediction intervals nor tolerance intervals produce funnel plot control limits that satisfy the nominal probability characteristics when there is uncertainty in the value of the benchmark. This is not necessarily to say that funnel plots have no role to play in healthcare, but that without the development of intervals satisfying the nominal probability characteristics they must be interpreted with care. © The Author(s) 2014.

Assessment of exposure to EMF in a Danish case-control study of childhood cancer.

PubMed

Jensen, J K; Olsen, J H; Folkersen, E

1994-01-01

In Denmark it is permitted to draw overhead lines across residential areas. In connection with a Danish case-control study we developed a method for estimating the historical values of magnetic fields at residences. The study included 1,707 cases with childhood cancer and 4,788 matched population controls. A total of 16,082 different addresses had been occupied by the families from the time of conception until the date of diagnosis. The values of the extreme, maximum, middle and minimum 50 Hz magnetic field strengths originating from a 50-400 kV high-voltage installation were estimated for each of the dwellings included in a potential exposure area. 30 children were exposed to an average level of magnetic fields of 0.1 microT or more. The evaluated Danish method of exposure assessment was compared with the method for residential wiring codes developed by Wertheimer and Leeper /1/. We concluded that the US wiring codes are inappropriate for use in connection with the Danish electricity transmission system.

Feature tracking CMR reveals abnormal strain in preclinical arrhythmogenic right ventricular dysplasia/ cardiomyopathy: a multisoftware feasibility and clinical implementation study.

PubMed

Bourfiss, Mimount; Vigneault, Davis M; Aliyari Ghasebeh, Mounes; Murray, Brittney; James, Cynthia A; Tichnell, Crystal; Mohamed Hoesein, Firdaus A; Zimmerman, Stefan L; Kamel, Ihab R; Calkins, Hugh; Tandri, Harikrishna; Velthuis, Birgitta K; Bluemke, David A; Te Riele, Anneline S J M

2017-09-01

Regional right ventricular (RV) dysfunction is the hallmark of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C), but is currently only qualitatively evaluated in the clinical setting. Feature Tracking Cardiovascular Magnetic Resonance (FT-CMR) is a novel quantitative method that uses cine CMR to calculate strain values. However, most prior FT-CMR studies in ARVD/C have focused on global RV strain using different software methods, complicating implementation of FT-CMR in clinical practice. We aimed to assess the clinical value of global and regional strain using FT-CMR in ARVD/C and to determine differences between commercially available FT-CMR software packages. We analyzed cine CMR images of 110 subjects (39 overt ARVD/C [mutation+/phenotype+], 40 preclinical ARVD/C [mutation+/phenotype-] and 31 control) for global and regional (subtricuspid, anterior, apical) RV strain in the horizontal longitudinal axis using four FT-CMR software methods (Multimodality Tissue Tracking, TomTec, Medis and Circle Cardiovascular Imaging). Intersoftware agreement was assessed using Bland Altman plots. For global strain, all methods showed reduced strain in overt ARVD/C patients compared to control subjects (p < 0.041), whereas none distinguished preclinical from control subjects (p > 0.275). For regional strain, overt ARVD/C patients showed reduced strain compared to control subjects in all segments which reached statistical significance in the subtricuspid region for all software methods (p < 0.037), in the anterior wall for two methods (p < 0.005) and in the apex for one method (p = 0.012). Preclinical subjects showed abnormal subtricuspid strain compared to control subjects using one of the software methods (p = 0.009). Agreement between software methods for absolute strain values was low (Intraclass Correlation Coefficient = 0.373). Despite large intersoftware variability of FT-CMR derived strain values, all four software methods distinguished overt ARVD/C patients from control subjects by both global and subtricuspid strain values. In the subtricuspid region, one software package distinguished preclinical from control subjects, suggesting the potential to identify early ARVD/C prior to overt disease expression.

Diffusing colloidal probes of protein-carbohydrate interactions.

PubMed

Eichmann, Shannon L; Meric, Gulsum; Swavola, Julia C; Bevan, Michael A

2013-02-19

We present diffusing colloidal probe measurements of weak, multivalent, specific protein-polysaccharide interactions mediated by a competing monosaccharide. Specifically, we used integrated evanescent wave and video microscopy methods to monitor the three-dimensional Brownian excursions of conconavilin A (ConA) decorated colloids interacting with dextran-functionalized surfaces in the presence of glucose. Particle trajectories were interpreted as binding lifetime histograms, binding isotherms, and potentials of mean force. Binding lifetimes and isotherms showed clear trends of decreasing ConA-dextran-specific binding with increasing glucose concentration, consistent with expectations. Net potentials were accurately captured by superposition of a short-range, glucose-independent ConA-dextran repulsion and a longer-range, glucose-dependent dextran bridging attraction modeled as a harmonic potential. For glucose concentrations greater than 100 mM, the net ConA-dextran potential was found to have only a nonspecific repulsion, similar to that of bovine serum albumin (BSA) decorated colloids over dextran determined in control experiments. Our results demonstrate the first use of optical microscopy methods to quantify the connections between potentials of mean force and the binding behavior of ConA-decorated colloids on dextran-functionalized surfaces.

In-house coordination for organ donation--single-center experience in a pilot project in Germany (2006 to 2013).

PubMed

Kaiser, G M; Wirges, U; Becker, S; Baier, C; Radunz, S; Kraus, H; Paul, A

2014-01-01

A challenge for solid organ transplantation in Germany is the shortage of organs. In an effort to increase donation rates, some federal states mandated hospitals to install transplantation officers to coordinate, evaluate, and enhance the donation and transplantation processes. In 2009 the German Foundation for Organ Transplantation (DSO) implemented the In-House Coordination Project, which includes retrospective, quarterly, information technology-based case analyses of all deceased patients with primary or secondary brain injury in regard to the organ donation process in maximum care hospitals. From 2006 to 2008 an analysis of potential organ donors was performed in our hospital using a time-consuming, complex method using questionnaires, hand-written patient files, and the hospital IT documentation system (standard method). Analyses in the In-House Coordination Project are instead carried out by a proprietary semiautomated IT tool called Transplant Check, which uses easily accessible standard data records of the hospital controlling and accounting unit. The aim of our study was to compare the results of the standard method and Transplant Check in detecting and evaluating potential donors. To do so, the same period of time (2006 to 2008) was re-evaluated using the IT tool. Transplant Check was able to record significantly more patients who fulfilled the criteria for inclusion than the standard method (641 vs 424). The methods displayed a wide overlap, apart from 22 patients who were only recorded by the standard method. In these cases, the accompanying brain injury diagnosis was not recorded in the controlling and accounting unit data records due to little relative clinical significance. None of the 22 patients fulfilled the criteria for brain death. In summary, Transplant Check is an easy-to-use, reliable, and valid tool for evaluating donor potential in a maximum care hospital. Therefore from 2010 on, analyses were performed exclusively with Transplant Check at our university hospital. Copyright © 2014 Elsevier Inc. All rights reserved.

Induction of antimicrobial 3-deoxyflavonoids in pome fruit trees controls fire blight.

PubMed

Halbwirth, Heidrun; Fischer, Thilo C; Roemmelt, Susanne; Spinelli, Francesco; Schlangen, Karin; Peterek, Silke; Sabatini, Emidio; Messina, Christian; Speakman, John-Bryan; Andreotti, Carlo; Rademacher, Wilhelm; Bazzi, Carlo; Costa, Guglielmo; Treutter, Dieter; Forkmann, Gert; Stich, Karl

2003-01-01

Fire blight, a devastating bacterial disease in pome fruits, causes severe economic losses worldwide. Hitherto, an effective control could only be achieved by using antibiotics, but this implies potential risks for human health, livestock and environment. A new approach allows transient inhibition of a step in the flavonoid pathway, thereby inducing the formation of a novel antimicrobial 3-deoxyflavonoid controlling fire blight in apple and pear leaves. This compound is closely related to natural phytoalexins in sorghum. The approach does not only provide a safe method to control fire blight: Resistance against different pathogens is also induced in other crop plants.

Size-Dependent Optoelectronic Properties and Controlled Doping of Semiconductor Quantum Dots

NASA Astrophysics Data System (ADS)

Engel, Jesse Hart

Given a rapidly developing world, the need exists for inexpensive renewable energy alternatives to help avoid drastic climate change. Photovoltaics have the potential to fill the energy needs of the future, but significant cost decreases are necessary for widespread adoption. Semiconductor nanocrystals, also known as quantum dots, are a nascent technology with long term potential to enable inexpensive and high efficiency photovoltaics. When deposited as a film, quantum dots form unique nanocomposites whose electronic and optical properties can be broadly tuned through manipulation of their individual constituents. The contents of this thesis explore methods to understand and optimize the optoelectronic properties of PbSe quantum dot films for use in photovoltaic applications. Systematic optimization of photovoltaic performance is demonstrated as a function of nanocrystal size, establishing the potential for utilizing extreme quantum confinement to improve device energetics and alignment. Detailed investigations of the mechanisms of electrical transport are performed, revealing that electronic coupling in quantum dot films is significantly less than often assumed based on optical shifts. A method is proposed to employ extended regions of built-in electrical field, through controlled doping, to sidestep issues of poor transport. To this end, treatments with chemical redox agents are found to effect profound and reversible doping within nanocrystal films, sufficient to enable their use as chemical sensors, but lacking the precision required for optoelectronic applications. Finally, a novel doping method employing "redox buffers" is presented to enact precise, stable, and reversible charge-transfer doping in porous semiconductor films. An example of oxidatively doping PbSe quantum dot thin films is presented, and the future potential for redox buffers in photovoltaic applications is examined.

FNAS phase partitions

NASA Technical Reports Server (NTRS)

Vanalstine, James M.

1993-01-01

Project NAS8-36955 D.O. #100 initially involved the following tasks: (1) evaluation of various coatings' ability to control wall wetting and surface zeta potential expression; (2) testing various methods to mix and control the demixing of phase systems; and (3) videomicroscopic investigation of cell partition. Three complementary areas were identified for modification and extension of the original contract. They were: (1) identification of new supports for column cell partition; (2) electrokinetic detection of protein adsorption; and (3) emulsion studies related to bioseparations.

Oral Treatment of Rodents with Insecticides for Control of Sand Flies (Diptera: Psychodidae) and the Fluorescent Tracer Technique (FTT) as a Tool to Evaluate Potential Sand Fly Control Methods

DTIC Science & Technology

2011-03-01

chitin synthesis inhibitors diflubenzuron and novaluron evaluated in these studies were...effective against sand fly larvae and palatable to hamsters. In contrast to the chitin synthesis inhibitors and juvenile hormone analogs...concentrations (mg/kg) Effects Chitin synthesis inhibitor Diflubenzuron 8.97, 89.7, 897 Mortality at larva-to-pupa molt Novaluron 9.88, 98.8,

Classical Optimal Control for Energy Minimization Based On Diffeomorphic Modulation under Observable-Response-Preserving Homotopy.

PubMed

Soley, Micheline B; Markmann, Andreas; Batista, Victor S

2018-06-12

We introduce the so-called "Classical Optimal Control Optimization" (COCO) method for global energy minimization based on the implementation of the diffeomorphic modulation under observable-response-preserving homotopy (DMORPH) gradient algorithm. A probe particle with time-dependent mass m( t;β) and dipole μ( r, t;β) is evolved classically on the potential energy surface V( r) coupled to an electric field E( t;β), as described by the time-dependent density of states represented on a grid, or otherwise as a linear combination of Gaussians generated by the k-means clustering algorithm. Control parameters β defining m( t;β), μ( r, t;β), and E( t;β) are optimized by following the gradients of the energy with respect to β, adapting them to steer the particle toward the global minimum energy configuration. We find that the resulting COCO algorithm is capable of resolving near-degenerate states separated by large energy barriers and successfully locates the global minima of golf potentials on flat and rugged surfaces, previously explored for testing quantum annealing methodologies and the quantum optimal control optimization (QuOCO) method. Preliminary results show successful energy minimization of multidimensional Lennard-Jones clusters. Beyond the analysis of energy minimization in the specific model systems investigated, we anticipate COCO should be valuable for solving minimization problems in general, including optimization of parameters in applications to machine learning and molecular structure determination.

Migraine classification using magnetic resonance imaging resting-state functional connectivity data.

PubMed

Chong, Catherine D; Gaw, Nathan; Fu, Yinlin; Li, Jing; Wu, Teresa; Schwedt, Todd J

2017-08-01

Background This study used machine-learning techniques to develop discriminative brain-connectivity biomarkers from resting-state functional magnetic resonance neuroimaging ( rs-fMRI) data that distinguish between individual migraine patients and healthy controls. Methods This study included 58 migraine patients (mean age = 36.3 years; SD = 11.5) and 50 healthy controls (mean age = 35.9 years; SD = 11.0). The functional connections of 33 seeded pain-related regions were used as input for a brain classification algorithm that tested the accuracy of determining whether an individual brain MRI belongs to someone with migraine or to a healthy control. Results The best classification accuracy using a 10-fold cross-validation method was 86.1%. Resting functional connectivity of the right middle temporal, posterior insula, middle cingulate, left ventromedial prefrontal and bilateral amygdala regions best discriminated the migraine brain from that of a healthy control. Migraineurs with longer disease durations were classified more accurately (>14 years; 96.7% accuracy) compared to migraineurs with shorter disease durations (≤14 years; 82.1% accuracy). Conclusions Classification of migraine using rs-fMRI provides insights into pain circuits that are altered in migraine and could potentially contribute to the development of a new, noninvasive migraine biomarker. Migraineurs with longer disease burden were classified more accurately than migraineurs with shorter disease burden, potentially indicating that disease duration leads to reorganization of brain circuitry.

Ensemble modelling and structured decision-making to support Emergency Disease Management.

PubMed

Webb, Colleen T; Ferrari, Matthew; Lindström, Tom; Carpenter, Tim; Dürr, Salome; Garner, Graeme; Jewell, Chris; Stevenson, Mark; Ward, Michael P; Werkman, Marleen; Backer, Jantien; Tildesley, Michael

2017-03-01

Epidemiological models in animal health are commonly used as decision-support tools to understand the impact of various control actions on infection spread in susceptible populations. Different models contain different assumptions and parameterizations, and policy decisions might be improved by considering outputs from multiple models. However, a transparent decision-support framework to integrate outputs from multiple models is nascent in epidemiology. Ensemble modelling and structured decision-making integrate the outputs of multiple models, compare policy actions and support policy decision-making. We briefly review the epidemiological application of ensemble modelling and structured decision-making and illustrate the potential of these methods using foot and mouth disease (FMD) models. In case study one, we apply structured decision-making to compare five possible control actions across three FMD models and show which control actions and outbreak costs are robustly supported and which are impacted by model uncertainty. In case study two, we develop a methodology for weighting the outputs of different models and show how different weighting schemes may impact the choice of control action. Using these case studies, we broadly illustrate the potential of ensemble modelling and structured decision-making in epidemiology to provide better information for decision-making and outline necessary development of these methods for their further application. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Electrowetting Controlled Tunable Liquid Microlens

NASA Astrophysics Data System (ADS)

Krupenkin, Tom; Yang, Shu

2002-03-01

Electrowetting potentially provides a convenient way to control the shape and position of the liquid droplet on a rigid substrate. However, the effectiveness of this method relies strongly on the precise control of the surface properties of the substrate. Here we present a tunable liquid microlens capable of adjusting the position of its focal spot in all three dimensions. The microlens consists of a droplet of a transparent conductive liquid placed on a dielectric substrate with a hydrophobic coating. By varying the voltage applied to the structure, both the position and the curvature of the microlens can be changed. The influence of the bulk and surface properties of the materials on the microlens behavior is experimentally investigated and supported by theoretical calculations. Some of the potential problems associated with the stick-slip behavior and contact angle hysteresis are outlined and possible ways to prevent them are suggested.

Fabrication of hydroxyapatite ceramics with controlled pore characteristics by slip casting.

PubMed

Yao, Xiumin; Tan, Shouhong; Jiang, Dongliang

2005-02-01

Porous hydroxyapatite (HAp) ceramics with controlled pore characteristics were fabricated using slip casting method by mixing PMMA with HAp powder. The optimum conditions of HAp slip for slip casting was achieved by employing various experimental techniques, zeta potential and sedimentation, as a function of pH of the slips in the pH range of 4-12. HAp suspensions displayed an absolute maximum in zeta potential values and a minimum in sedimentation height at pH 11.5. The optimal amount of dispersant for the HAp suspensions was found at 1.0 wt% according to the viscosity of 25 vol% HAp slurry. The rheological behaviour of HAp slurry displays a shear-thinning behavior without thixotropy, which is needed in slip casting processing. The pore characteristics of sintered porous hydroxyapatite bioceramics can be controlled by added PMMA particle size and volume. The obtained ceramics exhibit higher strength than those obtained by dry pressing.

Pokeweed (Phytolacca americana): possible source of a molluscicide

Treesearch

Arnold Krochmal; P.W. LeQuesne; P.W. LeQuesne

1970-01-01

Pokeweed, a plant abundant in Appalachia, exhibits some chemical similarities to a related species that has shown molluscicidal properties. Because this suggests that pokeweed, Phytolacca americana L. (P. decandra L.), has potential for controlling fresh-water snails, we have compiled this report of its chenlical composition, uses, propagation methods, and other...

Efficacy of white mustard and soybean meal as a bioherbicide in organic broccoli and spinach production

USDA-ARS?s Scientific Manuscript database

Weed control in organic cropping systems generally rely on mechanical or physical methods because of the lack of reliable organically accepted herbicides. Among the several potential bioherbicides being explored, white mustard (Sinapis alba) seed meal is among those bioherbicides that have been sho...

Potential Transport and Degradation of “Aged” Pesticide Residues in Soil

USDA-ARS?s Scientific Manuscript database

Increased pesticide residence time in soil, or “aging”, has been shown to affect the sorption-desorption of pesticides in the soil, which in turn can control transport and degradation processes. Aging effects have been characterized by batch sequential extraction methods, in which sorption coefficie...

Potential transport and degradation of “Aged” pesticide residues in soil

USDA-ARS?s Scientific Manuscript database

“Aging” has been shown to affect the sorption-desorption of pesticides in the soil, which in turn can control transport and degradation processes. Aging effects have been characterized by batch sequential extraction methods, in which sorption coefficients (i.e. Kd) are determined for the chemical re...

Workshop Report: Considerations for Developing Leaching Test Methods for Semi- and Non-Volatile Organic Compounds

EPA Pesticide Factsheets

Documents a September 2015 workshop on how to evaluate the potential for leaching of semi- or non-volatile organic constituents at contaminated sites where in place treatment has been used to control migration, and from waste that is disposed or re-used.

Examining the Intergenerational Transmission of Violence in a New Zealand Birth Cohort

ERIC Educational Resources Information Center

Fergusson, David M.; Boden, Joseph M.; Horwood, L. John

2006-01-01

Objective: This paper examines whether exposure to interparental violence in childhood predicts subsequent involvement in interpartner violence and violent crime after controlling for potentially confounding factors. Method: The investigation analyses data from the Christchurch Health and Development Study, a prospective, longitudinal study of a…

Body Mass Index Measurement in Schools

ERIC Educational Resources Information Center

Nihiser, Allison J.; Lee, Sarah M.; Wechsler, Howell; McKenna, Mary; Odom, Erica; Reinold, Chris; Thompson, Diane; Grummer-Strawn, Larry

2007-01-01

Background: School-based body mass index (BMI) measurement has attracted much attention across the nation from researchers, school officials, legislators, and the media as a potential approach to address obesity among youth. Methods: An expert panel, convened by the Centers for Disease Control and Prevention (CDC) in 2005, reviewed and provided…

Orienting apples for imaging using their inertial properties and random apple loading

USDA-ARS?s Scientific Manuscript database

The inability to control apple orientation during imaging has hindered development of automated systems for sorting apples for defects such as bruises and for safety issues such as fecal contamination. Recently, a potential method for orienting apples based on their inertial properties was discovere...

Assessment of 16 chemicals on proliferation and apoptosis in human neuroprogenitor cells using high-content image analysis (HCA).

EPA Science Inventory

The need for efficient methods of screening chemicals for the potential to cause developmental neurotoxicity is paramount. We previously described optimization of an HCA assay for proliferation and apoptosis in ReNcell CX cells (ReN), identifying appropriate controls. Utility of ...

Early Primary Invasion Scientists

ERIC Educational Resources Information Center

Spellman, Katie V.; Villano, Christine P.

2011-01-01

"We really need to get the government involved," said one student, holding his graph up to USDA scientist Steve Seefeldt. Dr. Steve studies methods to control "invasive" plants, plants that have been introduced to an area by humans and have potential to spread rapidly and negatively affect ecosystems. The first grader and his…

Functional and morphological analysis of putative chemoreception-related proteins in the lone star tick, Amblyomma americanum

USDA-ARS?s Scientific Manuscript database

Ehrlichiosis, a potentially fatal infection, is caused by rickettsial bacteria transmitted by the lone star tick, Amblyomma americanum. We previously analyzed the chemosensory appendage proteome of A. americanum as part of a project to develop new chemosensory-based vector control methods. Among the...

School Occupational Exposure to Bloodborne Pathogens. A Report To Provide Information.

ERIC Educational Resources Information Center

Iowa State Dept. of Education, Des Moines. Bureau of Special Education.

This report discusses a federally mandated standard concerning establishment of a program to reduce exposure to blood and other potentially infectious materials (OPIM) in Iowa schools and education agencies. The standard includes the following components: introduction, scope and application, definitions, exposure control, methods of compliance,…

Fault classification method for the driving safety of electrified vehicles

NASA Astrophysics Data System (ADS)

Wanner, Daniel; Drugge, Lars; Stensson Trigell, Annika

2014-05-01

A fault classification method is proposed which has been applied to an electric vehicle. Potential faults in the different subsystems that can affect the vehicle directional stability were collected in a failure mode and effect analysis. Similar driveline faults were grouped together if they resembled each other with respect to their influence on the vehicle dynamic behaviour. The faults were physically modelled in a simulation environment before they were induced in a detailed vehicle model under normal driving conditions. A special focus was placed on faults in the driveline of electric vehicles employing in-wheel motors of the permanent magnet type. Several failures caused by mechanical and other faults were analysed as well. The fault classification method consists of a controllability ranking developed according to the functional safety standard ISO 26262. The controllability of a fault was determined with three parameters covering the influence of the longitudinal, lateral and yaw motion of the vehicle. The simulation results were analysed and the faults were classified according to their controllability using the proposed method. It was shown that the controllability decreased specifically with increasing lateral acceleration and increasing speed. The results for the electric driveline faults show that this trend cannot be generalised for all the faults, as the controllability deteriorated for some faults during manoeuvres with low lateral acceleration and low speed. The proposed method is generic and can be applied to various other types of road vehicles and faults.

Ensuring pain relief for children at the end of life

PubMed Central

Grégoire, Marie-Claude; Frager, Gerri

2006-01-01

Pain management in the context of pediatric palliative care can be challenging. The present article reviews, through a case-based presentation, the nonpharmacological and pharmacological methods used to ensure adequate pain control in children facing end of life. Details on the impressive range of opioid dosages required and routes of administration are highlighted from published literature and clinical experience. Where available, evidence-based recommendations are provided. Potential side effects of pain medication and barriers to good pain control are discussed. Novel analgesics and innovative delivery methods are presented as future tools enhancing pain relief at the end of life. Some challenges to ethically grounded research in this important context of care are reviewed. PMID:16960633

Carbon monoxide – physiology, detection and controlled release

PubMed Central

Heinemann, Stefan H.; Hoshi, Toshinori; Westerhausen, Matthias

2014-01-01

Carbon monoxide (CO) is increasingly recognized as a cell-signalling molecule akin to nitric oxide (NO). CO has attracted particular attention as a potential therapeutic agent because of its reported anti-hypertensive, anti-inflammatory and cell-protective effects. We discuss recent progress in identifying new effector systems and elucidating the mechanisms of action of CO on, e.g., ion channels, as well as the design of novel methods to monitor CO in cellular environments. We also report on recent developments in the area of CO-releasing molecules (CORMs) and materials for controlled CO application. Novel triggers for CO release, metal carbonyls and degradation mechanisms of CORMs, are highlighted. In addition, potential formulations of CORMs for targeted CO release are discussed. PMID:24556640

Automation technology for aerospace power management

NASA Technical Reports Server (NTRS)

Larsen, R. L.

1982-01-01

The growing size and complexity of spacecraft power systems coupled with limited space/ground communications necessitate increasingly automated onboard control systems. Research in computer science, particularly artificial intelligence has developed methods and techniques for constructing man-machine systems with problem-solving expertise in limited domains which may contribute to the automation of power systems. Since these systems perform tasks which are typically performed by human experts they have become known as Expert Systems. A review of the current state of the art in expert systems technology is presented, and potential applications in power systems management are considered. It is concluded that expert systems appear to have significant potential for improving the productivity of operations personnel in aerospace applications, and in automating the control of many aerospace systems.

Setup for potential bias experiments on the Saha Institute of Nuclear Physics tokamak

NASA Astrophysics Data System (ADS)

Ghosh, J.; Pal, R.; Chattopadhyay, P. K.

1999-12-01

An experimental setup for studying the influence of the radial electric field on very low qa plasma on the Saha Institute of Nuclear Physics tokamak is presented. A high current, high voltage pulsed power supply, using a semiconductor controlled rectifier (SCR) as a dc switch is developed and used to bias a tungsten electrode inserted inside the plasma. The electrode's exposed length and its position inside the plasma are controlled by a double bellows assembly to optimize the electrode-exposed length. We show that using the force commutation method to turn the SCR off to get the power pulse desired has good potential for carrying out similar kinds of studies, especially in a low budget small tokamak.

Results from conceptual design study of potential early commercial MHD/steam power plants

NASA Technical Reports Server (NTRS)

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1981-01-01

This paper presents conceptual design information for a potential early MHD power plant developed in the second phase of a joint study of such plants. Conceptual designs of plant components and equipment with performance, operational characteristics and costs are reported on. Plant economics and overall performance including full and part load operation are reviewed. Environmental aspects and the methods incorporated in plant design for emission control of sulfur and nitrogen oxides are reviewed. Results from reliability/availability analysis conducted are also included.

The Potential Utility of Urinary Biomarkers for Risk Prediction in Combat Casualties: A Prospective Observational Cohort Study

DTIC Science & Technology

2015-06-16

are associated with poor outcomes, including death and the need for renal replacement therapy. Methods : We conducted a prospective, observational study...penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 16 JUN 2015...2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE The Potential Utility of Urinary Biomarkers for Risk Prediction in Combat

Saltcedar and Russian Olive Control Demonstration Act Science Assessment

USGS Publications Warehouse

Shafroth, Patrick B.; Brown, Curtis A.; Merritt, David M.

2010-01-01

The primary intent of this document is to provide the science assessment called for under The Saltcedar and Russian Olive Control Demonstration Act of 2006 (Public Law 109-320; the Act). A secondary purpose is to provide a common background for applicants for prospective demonstration projects, should funds be appropriated for this second phase of the Act. This document synthesizes the state-of-the-science on the following topics: the distribution and abundance (extent) of saltcedar (Tamarix spp.) and Russian olive (Elaeagnus angustifolia) in the Western United States, potential for water savings associated with controlling saltcedar and Russian olive and the associated restoration of occupied sites, considerations related to wildlife use of saltcedar and Russian olive habitat or restored habitats, methods to control saltcedar and Russian olive, possible utilization of dead biomass following removal of saltcedar and Russian olive, and approaches and challenges associated with revegetation or restoration following control efforts. A concluding chapter discusses possible long-term management strategies, needs for additional study, potentially useful field demonstration projects, and a planning process for on-the-ground projects involving removal of saltcedar and Russian olive.

Communication: Analytical optimal pulse shapes obtained with the aid of genetic algorithms: Controlling the photoisomerization yield of retinal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerrero, R. D., E-mail: rdguerrerom@unal.edu.co; Arango, C. A., E-mail: caarango@icesi.edu.co; Reyes, A., E-mail: areyesv@unal.edu.co

We recently proposed a Quantum Optimal Control (QOC) method constrained to build pulses from analytical pulse shapes [R. D. Guerrero et al., J. Chem. Phys. 143(12), 124108 (2015)]. This approach was applied to control the dissociation channel yields of the diatomic molecule KH, considering three potential energy curves and one degree of freedom. In this work, we utilized this methodology to study the strong field control of the cis-trans photoisomerization of 11-cis retinal. This more complex system was modeled with a Hamiltonian comprising two potential energy surfaces and two degrees of freedom. The resulting optimal pulse, made of 6 linearlymore » chirped pulses, was capable of controlling the population of the trans isomer on the ground electronic surface for nearly 200 fs. The simplicity of the pulse generated with our QOC approach offers two clear advantages: a direct analysis of the sequence of events occurring during the driven dynamics, and its reproducibility in the laboratory with current laser technologies.« less

Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes

NASA Technical Reports Server (NTRS)

Powell, Clemans A.; Sullivan, Brenda M.

2000-01-01

Active noise control technology offers the potential for weight-efficient aircraft interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.

Importance of ticks and their chemical and immunological control in livestock*

PubMed Central

Rajput, Zahid Iqbal; Hu, Song-hua; Chen, Wan-jun; Arijo, Abdullah G.; Xiao, Chen-wen

2006-01-01

The medical and economic importance of ticks has long been recognized due to their ability to transmit diseases to humans and animals. Ticks cause great economic losses to livestock, and adversely affect livestock hosts in several ways. Loss of blood is a direct effect of ticks acting as potential vector for haemo-protozoa and helminth parasites. Blood sucking by large numbers of ticks causes reduction in live weight and anemia among domestic animals, while their bites also reduce the quality of hides. However, major losses caused by ticks are due to their ability to transmit protozoan, rickettsial and viral diseases of livestock, which are of great economic importance world-wide. There are quite a few methods for controlling ticks, but every method has certain shortcomings. The present review is focused on ticks importance and their control. PMID:17048307

Manipulation of P2X Receptor Activities by Light Stimulation.

PubMed

Kim, Sang Seong

2016-01-01

P2X receptors are involved in amplification of inflammatory responses in peripheral nociceptive fibers and in mediating pain-related signals to the CNS. Control of P2X activation has significant importance in managing unwanted hypersensitive neuron responses. To overcome the limitations of chemical ligand treatment, optical stimulation methods of optogenetics and photoswitching achieve efficient control of P2X activation while allowing specificity at the target site and convenient stimulation by light illumination. There are many potential applications for photosensitive elements, such as improved uncaging methods, photoisomerizable ligands, photoswitches, and gold nanoparticles. Each technique has both advantages and downsides, and techniques are selected according to the purpose of the application. Technical advances not only provide novel approaches to manage inflammation or pain mediated by P2X receptors but also suggest a similar approach for controlling other ion channels.

A perfect correlate does not a surrogate make

PubMed Central

Baker, Stuart G; Kramer, Barnett S

2003-01-01

Background There is common belief among some medical researchers that if a potential surrogate endpoint is highly correlated with a true endpoint, then a positive (or negative) difference in potential surrogate endpoints between randomization groups would imply a positive (or negative) difference in unobserved true endpoints between randomization groups. We investigate this belief when the potential surrogate and unobserved true endpoints are perfectly correlated within each randomization group. Methods We use a graphical approach. The vertical axis is the unobserved true endpoint and the horizontal axis is the potential surrogate endpoint. Perfect correlation within each randomization group implies that, for each randomization group, potential surrogate and true endpoints are related by a straight line. In this scenario the investigator does not know the slopes or intercepts. We consider a plausible example where the slope of the line is higher for the experimental group than for the control group. Results In our example with unknown lines, a decrease in mean potential surrogate endpoints from control to experimental groups corresponds to an increase in mean true endpoint from control to experimental groups. Thus the potential surrogate endpoints give the wrong inference. Similar results hold for binary potential surrogate and true outcomes (although the notion of correlation does not apply). The potential surrogate endpointwould give the correct inference if either (i) the unknown lines for the two group coincided, which means that the distribution of true endpoint conditional on potential surrogate endpoint does not depend on treatment group, which is called the Prentice Criterion or (ii) if one could accurately predict the lines based on data from prior studies. Conclusion Perfect correlation between potential surrogate and unobserved true outcomes within randomized groups does not guarantee correct inference based on a potential surrogate endpoint. Even in early phase trials, investigators should not base conclusions on potential surrogate endpoints in which the only validation is high correlation with the true endpoint within a group. PMID:12962545

A novel method for beef potentiator preparation and identification of its characteristic aroma compounds.

PubMed

Gao, Xianli; Yan, Shuang; Yang, Bao; Lu, Jian; Jin, Zhao

2014-06-01

Beef potentiator (BP) is the most popular savoury flavour and regarded as the soul of the modern food industry. In this work, BP was prepared by a novel method with Aspergillus oryzae and Aspergillus niger (BPSF). Three other BPs prepared using commercial enzymes (Protamex, Flavourzyme and papain; BPCEs) were used as controls to investigate its aroma characteristics and related compounds. Sensory evaluation showed that BPSF possessed more favourable and distinctive sauce-like, meat-like, roast and alcoholic attributes when compared with BPCEs. Significantly higher contents (peak areas) and proportions of pyrazines, pyrroles, sulfurous compounds and alcohols in BPSF were responsible for its sensory characteristics, and most of these aroma compounds were derived from microbial metabolism during beef koji preparation and the Maillard reaction. BP prepared by synergistic fermentation with A. oryzae and A. niger is a potential alternative for BP preparation. © 2013 Society of Chemical Industry.

Marketing considerations in home health care.

PubMed

Tanner, D J

1985-12-01

Methods for conducting a comprehensive analysis of the potential for strategic entry or expansion in the home health-care (HHC) market are discussed. By conducting a comprehensive analysis of the HHC market, hospital pharmacists can evaluate the feasibility of developing and implementing a hospital-based HHC service. A comprehensive market analysis should include an initial assessment of potential product-line offerings, development of strengths-and-weaknesses and opportunities-and-threats profiles, evaluations of competing providers of HHC and regulatory issues, and formulation of a business plan. The potential impact of program structure, operations management, product pricing, advertising and promotion, and marketing controls should also be considered. The hospital pharmacist has a unique opportunity to further the organizational objectives of the hospital by participating in the provision of HHC; a comprehensive market analysis represents a useful method of assessing the benefits and costs associated with providing integrated HHC services.

Anticoagulation Control in Patients With Nonvalvular Atrial Fibrillation Attended at Primary Care Centers in Spain: The PAULA Study.

PubMed

Barrios, Vivencio; Escobar, Carlos; Prieto, Luis; Osorio, Genoveva; Polo, José; Lobos, José María; Vargas, Diego; García, Nicolás

2015-09-01

To determine the current status of anticoagulation control in patients with nonvalvular atrial fibrillation treated with vitamin K antagonists in the primary care setting in Spain. The PAULA study was a multicenter cross-sectional/retrospective observational study conducted throughout Spain. The study included patients with nonvalvular atrial fibrillation who had been receiving vitamin K antagonist therapy during the past year and were attended at primary care centers. International normalized ratio (INR) values over the past 12 months were recorded. The degree of anticoagulation control was defined as the time the patient had remained within the therapeutic range and was determined by both the direct method (poor control < 60%) and by the Rosendaal method (poor control < 65%). The study assessed 1524 patients (mean age, 77.4 ± 8.7 years; 48.6% women; 64.2% in permanent atrial fibrillation; CHADS2 mean, 2.3 ± 1.2; CHA2DS2-VASc, 3.9 ± 1.5, and HAS-BLED, 1.6 ± 0.9). The mean number of INR readings recorded per patient was 14.4 ± 3.8. A total of 56.9% of patients had adequate INR control according to the direct method and 60.6% according to the Rosendaal method. The multivariate analysis identified the following predictors for poor INR control: female sex, dietary habits potentially affecting anticoagulation with vitamin K antagonists, multidrug therapy, and a history of labile INR. Approximately 40% of patients (43.1% by the direct method and 39.4% by the Rosendaal method) with nonvalvular atrial fibrillation who were receiving anticoagulation therapy with vitamin K antagonists in primary care in Spain had poor anticoagulation control during the previous 12 months. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Public acceptance of management methods under different human-wildlife conflict scenarios.

PubMed

Liordos, Vasilios; Kontsiotis, Vasileios J; Georgari, Marina; Baltzi, Kerasia; Baltzi, Ioanna

2017-02-01

Wildlife management seeks to minimise public controversy for successful application of wildlife control methods. Human dimensions research in wildlife seeks a better understanding of public preferences for effective human-wildlife conflict resolution. In face to face interviews, 630 adults in Greece were asked to rate on a 5-point Likert-like scale their acceptance of 3 management methods, i.e., do nothing, non-lethal control, and lethal control, in the context of 5 human-wildlife conflict scenarios: 1) corvids damage crops; 2) starlings damage crops; 3) starlings foul urban structures; 4) coypus damage crops; and 5) coypus transfer disease. Univariate GLMs determined occupation, hunting membership and their interaction as the stronger predictors of public acceptance, generating 4 stakeholder groups: the general public, farmers, hunters, and farmers-hunters. Differences in acceptance and consensus among stakeholder groups were assessed using the Potential for Conflict Index 2 (PCI 2 ). All 4 stakeholder groups agreed that doing nothing was unacceptable and non-lethal control acceptable in all 5 scenarios, with generally high consensus within and between groups. The lethal control method was more controversial and became increasingly more acceptable as the severity of scenarios was increased and between non-native and native species. Lethal control was unacceptable for the general public in all scenarios. Farmers accepted lethal methods in the corvids and starlings scenarios, were neutral in the coypus damage crops scenario, whereas they accepted lethal control when coypus transfer disease. Hunters' opinion was neutral in the corvids, starlings and coypus damage crops and starlings foul urban structures scenarios, but they accepted lethal methods in the coypus transfer disease scenario. Farmers-hunters considered lethal control acceptable in all 5 scenarios. Implications from this study could be used for designing a socio-ecological approach which incorporates wildlife management with public interests. The studied species have a wide distribution, therefore present findings might also prove useful elsewhere. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of Contamination Inspection and Analysis Methods through Modeling System Performance

NASA Technical Reports Server (NTRS)

Seasly, Elaine; Dever, Jason; Stuban, Steven M. F.

2016-01-01

Contamination is usually identified as a risk on the risk register for sensitive space systems hardware. Despite detailed, time-consuming, and costly contamination control efforts during assembly, integration, and test of space systems, contaminants are still found during visual inspections of hardware. Improved methods are needed to gather information during systems integration to catch potential contamination issues earlier and manage contamination risks better. This research explores evaluation of contamination inspection and analysis methods to determine optical system sensitivity to minimum detectable molecular contamination levels based on IEST-STD-CC1246E non-volatile residue (NVR) cleanliness levels. Potential future degradation of the system is modeled given chosen modules representative of optical elements in an optical system, minimum detectable molecular contamination levels for a chosen inspection and analysis method, and determining the effect of contamination on the system. By modeling system performance based on when molecular contamination is detected during systems integration and at what cleanliness level, the decision maker can perform trades amongst different inspection and analysis methods and determine if a planned method is adequate to meet system requirements and manage contamination risk.

Implementation of a generic SFC-MS method for the quality control of potentially counterfeited medicinal cannabis with synthetic cannabinoids.

PubMed

Jambo, Hugues; Dispas, Amandine; Avohou, Hermane T; André, Sébastien; Hubert, Cédric; Lebrun, Pierre; Ziemons, Éric; Hubert, Philippe

2018-06-05

In this study, we describe the development of a SFC-MS method for the quality control of cannabis plants that could be potentially adulterated with synthetic cannabinoids. Considering the high number of already available synthetic cannabinoids and the high rate of development of novel structures, we aimed to develop a generic method suitable for the analysis of a large panel of substances using seventeen synthetic cannabinoids from multiple classes as model compounds. Firstly, a suitable column was chosen after a screening phase. Secondly, optimal operating conditions were obtained following a robust optimization strategy based on a design of experiments and design space methodology (DoE-DS). Finally, the quantitative performances of the method were assessed with a validation according to the total error approach. The developed method has a run time of 9.4 min. It uses a simple modifier composition of methanol with 2% H 2 O and requires minimal sample preparation. It can chromatographically separate natural cannabinoids (except THC-A and CBD-A) from the synthetics assessed. Also, the use of mass spectrometry provides sensitivity and specificity. Moreover, this quality by design (QbD) approach permits the tuning of the method (within the DS) during routine analysis to achieve a desirable separation since the future compounds that should be analyzed could be unknown. The method was validated for the quantitation of a selected synthetic cannabinoid in fiber-type cannabis matrix over the range of 2.5% - 7.5% (w/w) with LOD value as low as 14.4 ng/mL. This generic method should be easy to implement in customs or QC laboratories in the context of counterfeit drugs tracking. Copyright © 2018 Elsevier B.V. All rights reserved.

Aerodynamic shape optimization using control theory

NASA Technical Reports Server (NTRS)

Reuther, James

1996-01-01

Aerodynamic shape design has long persisted as a difficult scientific challenge due its highly nonlinear flow physics and daunting geometric complexity. However, with the emergence of Computational Fluid Dynamics (CFD) it has become possible to make accurate predictions of flows which are not dominated by viscous effects. It is thus worthwhile to explore the extension of CFD methods for flow analysis to the treatment of aerodynamic shape design. Two new aerodynamic shape design methods are developed which combine existing CFD technology, optimal control theory, and numerical optimization techniques. Flow analysis methods for the potential flow equation and the Euler equations form the basis of the two respective design methods. In each case, optimal control theory is used to derive the adjoint differential equations, the solution of which provides the necessary gradient information to a numerical optimization method much more efficiently then by conventional finite differencing. Each technique uses a quasi-Newton numerical optimization algorithm to drive an aerodynamic objective function toward a minimum. An analytic grid perturbation method is developed to modify body fitted meshes to accommodate shape changes during the design process. Both Hicks-Henne perturbation functions and B-spline control points are explored as suitable design variables. The new methods prove to be computationally efficient and robust, and can be used for practical airfoil design including geometric and aerodynamic constraints. Objective functions are chosen to allow both inverse design to a target pressure distribution and wave drag minimization. Several design cases are presented for each method illustrating its practicality and efficiency. These include non-lifting and lifting airfoils operating at both subsonic and transonic conditions.

SDRE controller for motion design of cable-suspended robot with uncertainties and moving obstacles

NASA Astrophysics Data System (ADS)

Behboodi, Ahad; Salehi, Seyedmohammad

2017-10-01

In this paper an optimal control approach for nonlinear dynamical systems was proposed based on State Dependent Riccati Equation (SDRE) and its robustness against uncertainties is shown by simulation results. The proposed method was applied on a spatial six-cable suspended robot, which was designed to carry loads or perform different tasks in huge workspaces. Motion planning for cable-suspended robots in such a big workspace is subjected to uncertainties and obstacles. First, we emphasized the ability of SDRE to construct a systematic basis and efficient design of controller for wide variety of nonlinear dynamical systems. Then we showed how this systematic design improved the robustness of the system and facilitated the integration of motion planning techniques with the controller. In particular, obstacle avoidance technique based on artificial potential field (APF) can be easily combined with SDRE controller with efficient performance. Due to difficulties of exact solution for SDRE, an approximation method was used based on power series expansion. The efficiency and robustness of the SDRE controller was illustrated on a six-cable suspended robot with proper simulations.

PSO-tuned PID controller for coupled tank system via priority-based fitness scheme

NASA Astrophysics Data System (ADS)

Jaafar, Hazriq Izzuan; Hussien, Sharifah Yuslinda Syed; Selamat, Nur Asmiza; Abidin, Amar Faiz Zainal; Aras, Mohd Shahrieel Mohd; Nasir, Mohamad Na'im Mohd; Bohari, Zul Hasrizal

2015-05-01

The industrial applications of Coupled Tank System (CTS) are widely used especially in chemical process industries. The overall process is require liquids to be pumped, stored in the tank and pumped again to another tank. Nevertheless, the level of liquid in tank need to be controlled and flow between two tanks must be regulated. This paper presents development of an optimal PID controller for controlling the desired liquid level of the CTS. Two method of Particle Swarm Optimization (PSO) algorithm will be tested in optimizing the PID controller parameters. These two methods of PSO are standard Particle Swarm Optimization (PSO) and Priority-based Fitness Scheme in Particle Swarm Optimization (PFPSO). Simulation is conducted within Matlab environment to verify the performance of the system in terms of settling time (Ts), steady state error (SSE) and overshoot (OS). It has been demonstrated that implementation of PSO via Priority-based Fitness Scheme (PFPSO) for this system is potential technique to control the desired liquid level and improve the system performances compared with standard PSO.

Sliding Mode Approaches for Robust Control, State Estimation, Secure Communication, and Fault Diagnosis in Nuclear Systems

NASA Astrophysics Data System (ADS)

Ablay, Gunyaz

Using traditional control methods for controller design, parameter estimation and fault diagnosis may lead to poor results with nuclear systems in practice because of approximations and uncertainties in the system models used, possibly resulting in unexpected plant unavailability. This experience has led to an interest in development of robust control, estimation and fault diagnosis methods. One particularly robust approach is the sliding mode control methodology. Sliding mode approaches have been of great interest and importance in industry and engineering in the recent decades due to their potential for producing economic, safe and reliable designs. In order to utilize these advantages, sliding mode approaches are implemented for robust control, state estimation, secure communication and fault diagnosis in nuclear plant systems. In addition, a sliding mode output observer is developed for fault diagnosis in dynamical systems. To validate the effectiveness of the methodologies, several nuclear plant system models are considered for applications, including point reactor kinetics, xenon concentration dynamics, an uncertain pressurizer model, a U-tube steam generator model and a coupled nonlinear nuclear reactor model.

Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix D. Assessment of NO/sub x/ control technology for coal fired utility boilers. [Low-excess-air, staged combustion, flu gas recirculation and burner design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-12-01

An NOx control technology assessment study was conducted to examine the effectiveness of low-excess-air firing, staged combustion, flue gas recirculation, and current burner/boiler designs as applied to coal-fired utility boilers. Significant variations in NOx emissions exist with boiler type, firing method, and coal type, but a relative comparison of emissions control performance, cost, and operational considerations is presented for each method. The study emphasized the numerous operational factors that are of major importance to the user in selecting and implementing a combustion modification technique. Staged combustion and low-excess-air operation were identified as the most cost-effective methods for existing units. Closemore » control of local air/fuel ratios and rigorous combustion equipment maintenance are essential to the success of both methods. Flue gas recirculation is relatively ineffective and has the added concern of tube erosion. More research is needed to resolve potential corrosion concerns with low-NOx operating modes. Low-NOx burners in conjunction with a compartmentalized windbox are capable of meeting a 0.6-lb/million Btu emission level on new units. Advanced burner designs are being developed to meet research emission goals of approximately 0.25 lb/MBtu.« less

A multi-refuge study to evaluate the effectiveness of growing-season and dormant-season burns to control cattail

USGS Publications Warehouse

Gleason, Robert A.; Tangen, Brian A.; Laubhan, Murray K.; Lor, Socheata

2012-01-01

Proliferation of invasive cattails (for example, Typha x glauca, T. angustifolia) is a concern of wetland managers across the country, and numerous methods have been used to control the spatial extent and density of the plant. To date, however, no single method has proven widely or consistently effective at reducing the long-term growth and spread of these species. We performed a multi-refuge study to evaluate the relative effects of growing-season and dormant-season prescribed burns on cattail production and to gain insight on variables such as soil moisture, groundwater, and biomass that affect the efficacy of burning as a control method. Results indicate total cattail cover recovers to pre-burn levels within 1 year regardless of whether the controlled burn was implemented during the growing season or dormant season. Growing-season burns, however, did result in lower aboveground and belowground cattail biomass 1-year post-burn, whereas no significant change in biomass was detected for dormant-season burns. Study results support the premise that burns implemented during the growing season should have a greater effect on nutrient reserves and cattail re-growth. Results from this and other studies suggest long-term research that incorporates multiple management strategies will be required to evaluate the potential of prescribed burning as a method to control cattail.

Pulsed laser versus electrical energy for peripheral nerve stimulation

PubMed Central

Wells, Jonathon; Konrad, Peter; Kao, Chris; Jansen, E. Duco; Mahadevan-Jansen, Anita

2010-01-01

Transient optical neural stimulation has previously been shown to elicit highly controlled, artifact-free potentials within the nervous system in a non-contact fashion without resulting in damage to tissue. This paper presents the physiologic validity of elicited nerve and muscle potentials from pulsed laser induced stimulation of the peripheral nerve in a comparative study with the standard method of electrically evoked potentials. Herein, the fundamental physical properties underlying the two techniques are contrasted. Key laser parameters for efficient optical stimulation of the peripheral nerve are detailed. Strength response curves are shown to be linear for each stimulation modality, although fewer axons can be recruited with optically evoked potentials. Results compare the relative transient energy requirements for stimulation using each technique and demonstrate that optical methods can selectively excite functional nerve stimulation. Adjacent stimulation and recording of compound nerve potentials in their entirety from optical and electrical stimulation are presented, with optical responses shown to be free of any stimulation artifact. Thus, use of a pulsed laser exhibits some advantages when compared to standard electrical means for excitation of muscle potentials in the peripheral nerve in the research domain and possibly for clinical diagnostics in the future. PMID:17537515

Isolation of osteoprogenitors from human jaw periosteal cells: a comparison of two magnetic separation methods.

PubMed

Olbrich, Marcus; Rieger, Melanie; Reinert, Siegmar; Alexander, Dorothea

2012-01-01

Human jaw periosteum tissue contains osteoprogenitors that have potential for tissue engineering applications in oral and maxillofacial surgeries. To isolate osteoprogenitor cells from heterogeneous cell populations, we used the specific mesenchymal stem cell antigen-1 (MSCA-1) antibody and compared two magnetic separation methods. We analyzed the obtained MSCA-1(+) and MSCA-1(-) fractions in terms of purity, yield of positive/negative cells and proliferative and mineralization potentials. The analysis of cell viability after separation revealed that the EasySep method yielded higher viability rates, whereas the flow cytometry results showed a higher purity for the MACS-separated cell fractions. The mineralization capacity of the osteogenic induced MSCA-1(+) cells compared with the MSCA-1(-) controls using MACS was 5-fold higher, whereas the same comparison after EasySep showed no significant differences between both fractions. By analyzing cell proliferation, we detected a significant difference between the proliferative potential of the osteogenic cells versus untreated cells after the MACS and EasySep separations. The differentiated cells after MACS separation adjusted their proliferative capacity, whereas the EasySep-separated cells failed to do so. The protein expression analysis showed small differences between the two separation methods. Our findings suggest that MACS is a more suitable separation method to isolate osteoprogenitors from the entire jaw periosteal cell population.

Reliable determination of new lipid peroxidation compounds as potential early Alzheimer Disease biomarkers.

PubMed

García-Blanco, Ana; Peña-Bautista, Carmen; Oger, Camille; Vigor, Claire; Galano, Jean-Marie; Durand, Thierry; Martín-Ibáñez, Nuria; Baquero, Miguel; Vento, Máximo; Cháfer-Pericás, Consuelo

2018-07-01

Lipid peroxidation plays an important role in Alzheimer Disease, so corresponding metabolites found in urine samples could be potential biomarkers. The aim of this work is to develop a reliable ultra-performance liquid chromatography-tandem mass spectrometry analytical method to determine a new set of lipid peroxidation compounds in urine samples. Excellent sensitivity was achieved with limits of detection between 0.08 and 17 nmol L -1 , which renders this method suitable to monitor analytes concentrations in real samples. The method's precision was satisfactory with coefficients of variation around 5-17% (intra-day) and 8-19% (inter-day). The accuracy of the method was assessed by analysis of spiked urine samples obtaining recoveries between 70% and 120% for most of the analytes. The utility of the described method was tested by analyzing urine samples from patients early diagnosed with mild cognitive impairment or mild dementia Alzheimer Disease following the clinical standard criteria. As preliminary results, some analytes (17(RS)-10-epi-SC-Δ 15 -11-dihomo-IsoF, PGE 2 ) and total parameters (Neuroprostanes, Isoprostanes, Isofurans) show differences between the control and the clinical groups. So, these analytes could be potential early Alzheimer Disease biomarkers assessing the patients' pro-oxidant condition. Copyright © 2018 Elsevier B.V. All rights reserved.

Investigation of urinary volatile organic metabolites as potential cancer biomarkers by solid-phase microextraction in combination with gas chromatography-mass spectrometry

PubMed Central

Silva, C L; Passos, M; Câmara, J S

2011-01-01

Background: Non-invasive diagnostic strategies aimed at identifying biomarkers of cancer are of great interest for early cancer detection. Urine is potentially a rich source of volatile organic metabolites (VOMs) that can be used as potential cancer biomarkers. Our aim was to develop a generally reliable, rapid, sensitive, and robust analytical method for screening large numbers of urine samples, resulting in a broad spectrum of native VOMs, as a tool to evaluate the potential of these metabolites in the early diagnosis of cancer. Methods: To investigate urinary volatile metabolites as potential cancer biomarkers, urine samples from 33 cancer patients (oncological group: 14 leukaemia, 12 colorectal and 7 lymphoma) and 21 healthy (control group, cancer-free) individuals were qualitatively and quantitatively analysed. Dynamic solid-phase microextraction in headspace mode (dHS-SPME) using a carboxen-polydimethylsiloxane (CAR/PDMS) sorbent in combination with GC-qMS-based metabolomics was applied to isolate and identify the volatile metabolites. This method provides a potential non-invasive method for early cancer diagnosis as a first approach. To fulfil this objective, three important dHS-SPME experimental parameters that influence extraction efficiency (fibre coating, extraction time and temperature of sampling) were optimised using a univariate optimisation design. The highest extraction efficiency was obtained when sampling was performed at 50°C for 60 min using samples with high ionic strengths (17% sodium chloride, w v−1) and under agitation. Results: A total of 82 volatile metabolites belonging to distinct chemical classes were identified in the control and oncological groups. Benzene derivatives, terpenoids and phenols were the most common classes for the oncological group, whereas ketones and sulphur compounds were the main classes that were isolated from the urine headspace of healthy subjects. The results demonstrate that compound concentrations were dramatically different between cancer patients and healthy volunteers. The positive rates of 16 patients among the 82 identified were found to be statistically different (P<0.05). A significant increase in the peak area of 2-methyl-3-phenyl-2-propenal, p-cymene, anisole, 4-methyl-phenol and 1,2-dihydro-1,1,6-trimethyl-naphthalene in cancer patients was observed. On average, statistically significant lower abundances of dimethyl disulphide were found in cancer patients. Conclusions: Gas chromatographic peak areas were submitted to multivariate analysis (principal component analysis and supervised linear discriminant analysis) to visualise clusters within cases and to detect the volatile metabolites that are able to differentiate cancer patients from healthy individuals. Very good discrimination within cancer groups and between cancer and control groups was achieved. PMID:22085842

New DEA rules expand options for controlled substance disposal.

PubMed

Peterson, David M

2015-03-01

Prescription drug abuse and overdose are rapidly growing problems in the United States. The United States federal Disposal of Controlled Substances Rule became effective 9 October 2014, implementing the Secure and Responsible Drug Disposal Act of 2010 (Disposal Act). These regulations target escalating prescription drug misuse by reducing accumulation of unused controlled substances that may be abused, diverted or accidentally ingested. Clinical areas that can now participate in collecting unused controlled substances include retail pharmacies, hospitals or clinics with an onsite pharmacy, and narcotic treatment programs. Collection methods include placing a controlled substance collection receptacle or instituting a mail-back program. Because prompt onsite destruction of collected items is required of mail-back programs, collection receptacles are more likely to be used in clinical areas. Retail pharmacies and hospitals or clinics with an onsite pharmacy may also place and maintain collection receptacles at long-term care facilities. The Act and Rule are intended to increase controlled substance disposal methods and expand local involvement in collection of unused controlled substances. Potential barriers to participating in controlled substance collection include acquisition of suitable collection receptacles and liners, lack of available space meeting the necessary criteria, lack of employee time for verification and inventory requirements, and program costs.

The biocompatibility of modified experimental Portland cements with potential for use in dentistry.

PubMed

Camilleri, J

2008-12-01

To evaluate the biocompatibility of a group of new potential dental materials and their eluants by assessing cell viability. Calcium sulpho-aluminate cement (CSA), calcium fluoro-aluminate cement (CFA) and glass-ionomer cement (GIC; Ketac Molar), used as the control, were tested for biocompatibility. Using a direct test method cell viability was measured quantitatively using alamarBluetrade mark dye, and an indirect test method where cells were grown on material elutions and cell viability was assessed using methyltetrazolium (MTT) assay as recommended by ISO 10 993-Part 5 for in vitro testing. Statistical analysis was performed by analysis of variance and Tukey multi-comparison test method. Elution collected from the prototype cements and the GIC cured for 1 and 7 days allowed high cell activity after 24 h cell exposure, which reduced after 48 h when compared to the nontoxic glass-ionomer control, but increased significantly after 72 h cell contact. Elutions collected after 28 days revealed reduced cell activity at all cell exposure times. Cells placed in direct contact with the prototype materials showed reduced cell activity when compared with the control. Cell growth was poor when seeded in direct contact with the prototype cements. GIC encouraged cell growth after 1 day of contact. The eluted species for all the cements tested exhibited adequate cell viability in the early ages with reduced cell activity at 28 days. Changes in the production of calcium hydroxide as a by-product of cement hydration affect the material biocompatibility adversely.

Improving power and robustness for detecting genetic association with extreme-value sampling design.

PubMed

Chen, Hua Yun; Li, Mingyao

2011-12-01

Extreme-value sampling design that samples subjects with extremely large or small quantitative trait values is commonly used in genetic association studies. Samples in such designs are often treated as "cases" and "controls" and analyzed using logistic regression. Such a case-control analysis ignores the potential dose-response relationship between the quantitative trait and the underlying trait locus and thus may lead to loss of power in detecting genetic association. An alternative approach to analyzing such data is to model the dose-response relationship by a linear regression model. However, parameter estimation from this model can be biased, which may lead to inflated type I errors. We propose a robust and efficient approach that takes into consideration of both the biased sampling design and the potential dose-response relationship. Extensive simulations demonstrate that the proposed method is more powerful than the traditional logistic regression analysis and is more robust than the linear regression analysis. We applied our method to the analysis of a candidate gene association study on high-density lipoprotein cholesterol (HDL-C) which includes study subjects with extremely high or low HDL-C levels. Using our method, we identified several SNPs showing a stronger evidence of association with HDL-C than the traditional case-control logistic regression analysis. Our results suggest that it is important to appropriately model the quantitative traits and to adjust for the biased sampling when dose-response relationship exists in extreme-value sampling designs. © 2011 Wiley Periodicals, Inc.

Field investigation on the repellent activity of some aromatic plants by traditional means against Anopheles arabiensis and An. pharoensis (Diptera: Culicidae) around Koka, central Ethiopia.

PubMed

Dugassa, Sisay; Medhin, Girmay; Balkew, Meshesha; Seyoum, Aklilu; Gebre-Michael, Teshome

2009-10-01

A study was undertaken to evaluate the impact of traditional application methods of mosquito repellent plants in the reduction of the human-vector contact of malaria vectors in central Ethiopia. The plants (Corymbia citriodora, Eucalyptus camaldulensis, Ocimum suave and Ocimum basilicum) were tested by thermal expulsion and direct burning on traditional stoves in the field against two important malaria vectors in Ethiopia (Anopheles arabiensis and An. pharoensis). A Latin-square design was applied for randomly assigning the treatment plants and control to experimental houses over different nights. The percentage repellency of each candidate plant by both application methods was estimated from the catches of mosquitoes in the treatment and control houses. On direct burning of the plants, O. basilicum showed the highest percentage repellency (73.11%, P<0.001) and E. camaldulensis the least repellency (65.29%, P<0.001) against An. arabiensis. By the same method of application, C. citriodora on the other hand gave the highest repellency (72.87%, P<0.001) while E. camaldulensis was still the least repellent plant (66.60%, P<0.001) against An. pharoensis. On thermal expulsion, C. citriodora exhibited the highest repellency (78.69%, P<0.001) while E. camaldulensis was the lowest repellent plant (71.91%, P<0.001) against An. arabiensis. Against An. pharoensis, C. citriodora gave the highest repellency (72.9%, P<0.001) while E. camaldulensis still gave the least repellency (72.2%, P<0.001) on the same method of application. All the tested plants by both methods of application gave partial but significant protection (>65%) against the house-entry and biting of two important malaria vectors in Ethiopia, and thus have a potential to be used at least as supplements to other control methods. However, feasibility and actual impact on disease transmission need to be known on these and other potentially useful plants.

Controlling range expansion in habitat networks by adaptively targeting source populations.

PubMed

Hock, Karlo; Wolff, Nicholas H; Beeden, Roger; Hoey, Jessica; Condie, Scott A; Anthony, Kenneth R N; Possingham, Hugh P; Mumby, Peter J

2016-08-01

Controlling the spread of invasive species, pests, and pathogens is often logistically limited to interventions that target specific locations at specific periods. However, in complex, highly connected systems, such as marine environments connected by ocean currents, populations spread dynamically in both space and time via transient connectivity links. This results in nondeterministic future distributions of species in which local populations emerge dynamically and concurrently over a large area. The challenge, therefore, is to choose intervention locations that will maximize the effectiveness of the control efforts. We propose a novel method to manage dynamic species invasions and outbreaks that identifies the intervention locations most likely to curtail population expansion by selectively targeting local populations most likely to expand their future range. Critically, at any point during the development of the invasion or outbreak, the method identifies the local intervention that maximizes the long-term benefit across the ecosystem by restricting species' potential to spread. In so doing, the method adaptively selects the intervention targets under dynamically changing circumstances. To illustrate the effectiveness of the method we applied it to controlling the spread of crown-of-thorns starfish (Acanthaster sp.) outbreaks across Australia's Great Barrier Reef. Application of our method resulted in an 18-fold relative improvement in management outcomes compared with a random targeting of reefs in putative starfish control scenarios. Although we focused on applying the method to reducing the spread of an unwanted species, it can also be used to facilitate the spread of desirable species through connectivity networks. For example, the method could be used to select those fragments of habitat most likely to rebuild a population if they were sufficiently well protected. © 2016 Society for Conservation Biology.

On-Line Control of Glucose Concentration in High-Yielding Mammalian Cell Cultures Enabled Through Oxygen Transfer Rate Measurements.

PubMed

Goldrick, Stephen; Lee, Kenneth; Spencer, Christopher; Holmes, William; Kuiper, Marcel; Turner, Richard; Farid, Suzanne S

2018-04-01

Glucose control is vital to ensure consistent growth and protein production in mammalian cell cultures. The typical fed-batch glucose control strategy involving bolus glucose additions based on infrequent off-line daily samples results in cells experiencing significant glucose concentration fluctuations that can influence product quality and growth. This study proposes an on-line method to control and manipulate glucose utilizing readily available process measurements. The method generates a correlation between the cumulative oxygen transfer rate and the cumulative glucose consumed. This correlation generates an on-line prediction of glucose that has been successfully incorporated into a control algorithm manipulating the glucose feed-rate. This advanced process control (APC) strategy enables the glucose concentration to be maintained at an adjustable set-point and has been found to significantly reduce the deviation in glucose concentration in comparison to conventional operation. This method has been validated to produce various therapeutic proteins across cell lines with different glucose consumption demands and is successfully demonstrated on micro (15 mL), laboratory (7 L), and pilot (50 L) scale systems. This novel APC strategy is simple to implement and offers the potential to significantly enhance the glucose control strategy for scales spanning micro-scale systems through to full scale industrial bioreactors. © 2018 The Authors. Biotechnology Journal Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Experimental Investigation of Ice Phase Change Material Heat Exchangers

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Stephan, Ryan A.

2011-01-01

Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

Experimental Investigation of Ice Phase Change Material Heat Exchangers

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Stephan, Ryan A.

2012-01-01

Phase change materials (PCM) may be useful for spacecraft thermal control systems that involve cyclical heat loads or cyclical thermal environments. Thermal energy can be stored in the PCM during peak heat loads or in adverse thermal environments. The stored thermal energy can then be released later during minimum heat loads or in more favorable thermal environments. This can result in a decreased turndown ratio for the radiator and a reduced system mass. The use of water as a PCM rather than the more traditional paraffin wax has the potential for significant mass reduction since the latent heat of formation of water is approximately 70% greater than that of wax. One of the potential drawbacks of using ice as a PCM is its potential to rupture its container as water expands upon freezing. In order to develop a space qualified ice PCM heat exchanger, failure mechanisms must first be understood. Therefore, a methodical experimental investigation has been undertaken to demonstrate and document specific failure mechanisms due to ice expansion in the PCM. A number of ice PCM heat exchangers were fabricated and tested. Additionally, methods for controlling void location in order to reduce the risk of damage due to ice expansion were investigated. This paper presents an overview of the results of this investigation from the past three years.

A multi-scale residual-based anti-hourglass control for compatible staggered Lagrangian hydrodynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kucharik, M.; Scovazzi, Guglielmo; Shashkov, Mikhail Jurievich

Hourglassing is a well-known pathological numerical artifact affecting the robustness and accuracy of Lagrangian methods. There exist a large number of hourglass control/suppression strategies. In the community of the staggered compatible Lagrangian methods, the approach of sub-zonal pressure forces is among the most widely used. However, this approach is known to add numerical strength to the solution, which can cause potential problems in certain types of simulations, for instance in simulations of various instabilities. To avoid this complication, we have adapted the multi-scale residual-based stabilization typically used in the finite element approach for staggered compatible framework. In this study, wemore » describe two discretizations of the new approach and demonstrate their properties and compare with the method of sub-zonal pressure forces on selected numerical problems.« less

Depressing thermal conductivity of fullerene by caging rare gas

NASA Astrophysics Data System (ADS)

Li, Jian; Zheng, Dong-Qin; Zhong, Wei-Rong

2016-01-01

We have investigated the thermal conductivity of C60 and its derivatives caged with rare gas by using the nonequilibrium molecular dynamics method. It is reported that embedding C60 with different rare gas atoms has a significant impact on its thermal conductivity. We analyze the phenomenon through the phonon spectra of rare gas atom and the C-C bonds length of C60. When the number of atoms inside the C60 increases, the phonon spectra band width of rare gas expands and the length of C-C bonds becomes longer, which contributes to the depression of the thermal conductivity of C60. The method is applied to control the thermal conductivity of C60 chains, which maybe a kind of potential materials in thermal circuits. Our results also provide a controllable method for the thermal management in nanoscale materials.

Classification of Weed Species Using Artificial Neural Networks Based on Color Leaf Texture Feature

NASA Astrophysics Data System (ADS)

Li, Zhichen; An, Qiu; Ji, Changying

The potential impact of herbicide utilization compel people to use new method of weed control. Selective herbicide application is optimal method to reduce herbicide usage while maintain weed control. The key of selective herbicide is how to discriminate weed exactly. The HIS color co-occurrence method (CCM) texture analysis techniques was used to extract four texture parameters: Angular second moment (ASM), Entropy(E), Inertia quadrature (IQ), and Inverse difference moment or local homogeneity (IDM).The weed species selected for studying were Arthraxon hispidus, Digitaria sanguinalis, Petunia, Cyperus, Alternanthera Philoxeroides and Corchoropsis psilocarpa. The software of neuroshell2 was used for designing the structure of the neural network, training and test the data. It was found that the 8-40-1 artificial neural network provided the best classification performance and was capable of classification accuracies of 78%.

A multi-scale residual-based anti-hourglass control for compatible staggered Lagrangian hydrodynamics

DOE PAGES

Kucharik, M.; Scovazzi, Guglielmo; Shashkov, Mikhail Jurievich; ...

2017-10-28

Hourglassing is a well-known pathological numerical artifact affecting the robustness and accuracy of Lagrangian methods. There exist a large number of hourglass control/suppression strategies. In the community of the staggered compatible Lagrangian methods, the approach of sub-zonal pressure forces is among the most widely used. However, this approach is known to add numerical strength to the solution, which can cause potential problems in certain types of simulations, for instance in simulations of various instabilities. To avoid this complication, we have adapted the multi-scale residual-based stabilization typically used in the finite element approach for staggered compatible framework. In this study, wemore » describe two discretizations of the new approach and demonstrate their properties and compare with the method of sub-zonal pressure forces on selected numerical problems.« less

System and Method for Providing Model-Based Alerting of Spatial Disorientation to a Pilot

NASA Technical Reports Server (NTRS)

Johnson, Steve (Inventor); Conner, Kevin J (Inventor); Mathan, Santosh (Inventor)

2015-01-01

A system and method monitor aircraft state parameters, for example, aircraft movement and flight parameters, applies those inputs to a spatial disorientation model, and makes a prediction of when pilot may become spatially disoriented. Once the system predicts a potentially disoriented pilot, the sensitivity for alerting the pilot to conditions exceeding a threshold can be increased and allow for an earlier alert to mitigate the possibility of an incorrect control input.

Silver biocide's real-world success.

PubMed

Pearson, Susan

2015-03-01

Although temperature control has been the UK's longest-serving means of controlling the growth and proliferation of Legionella in hot and cold water systems, there are other factors, including major rises in energy costs, that warrant the use of biocides--including in the healthcare sector. In 2000, the HSE's new 'L8' guidelines took this into account, giving equal weight to both temperature reg~mes and biocides, such as chlorine dioxide, as control methods. Susan Pearson BSc reports on one potentially effective biocide- silver hydrogen peroxide, explains how it 'works' in practice, and highlights the recent 'real-world' evidence of its effectiveness and advantages.

Refining fuzzy logic controllers with machine learning

NASA Technical Reports Server (NTRS)

Berenji, Hamid R.

1994-01-01

In this paper, we describe the GARIC (Generalized Approximate Reasoning-Based Intelligent Control) architecture, which learns from its past performance and modifies the labels in the fuzzy rules to improve performance. It uses fuzzy reinforcement learning which is a hybrid method of fuzzy logic and reinforcement learning. This technology can simplify and automate the application of fuzzy logic control to a variety of systems. GARIC has been applied in simulation studies of the Space Shuttle rendezvous and docking experiments. It has the potential of being applied in other aerospace systems as well as in consumer products such as appliances, cameras, and cars.

Magnetically controlled multifrequency invisibility cloak with a single shell of ferrite material

NASA Astrophysics Data System (ADS)

Wang, Xiaohua; Liu, Youwen

2015-02-01

A magnetically controlled multifrequency invisibility cloak with a single shell of the isotropic and homogeneous ferrite material has been investigated based on the scattering cancellation method from the Mie scattering theory. The analytical and simulated results have demonstrated that such this shell can drastically reduce the total scattering cross-section of this cloaking system at multiple frequencies. These multiple cloaking frequencies of this shell can be externally controlled since the magnetic permeability of ferrites is well tuned by the applied magnetic field. This may provide a potential way to design a tunable multifrequency invisibility cloak with considerable flexibility.

Accurate calibration and control of relative humidity close to 100% by X-raying a DOPC multilayer

DOE PAGES

Ma, Yicong; Ghosh, Sajal K.; Bera, Sambhunath; ...

2015-01-01

Here in this study, we have designed a compact sample chamber that can achieve accurate and continuous control of the relative humidity (RH) in the vicinity of 100%. A 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayer can be used as a humidity sensor by measuring its inter-layer repeat distance (d-spacing) via X-ray diffraction. We convert from DOPC d-spacing to RH according to a theory given in the literature and previously measured data of DOPC multilamellar vesicles in polyvinylpyrrolidone (PVP) solutions. This curve can be used for calibration of RH close to 100%, a regime where conventional sensors do not have sufficient accuracy. We demonstratemore » that this control method can provide RH accuracies of 0.1 to 0.01%, which is a factor of 10–100 improvement compared to existing methods of humidity control. Our method provides fine tuning capability of RH continuously for a single sample, whereas the PVP solution method requires new samples to be made for each PVP concentration. The use of this cell also potentially removes the need for an X-ray or neutron beam to pass through bulk water if one wishes to work close to biologically relevant conditions of nearly 100% RH.« less

Novel bacteriophage therapy for controlling metallo-beta-lactamase producing Pseudomonas aeruginosa infection in Catfish

PubMed Central

2013-01-01

Background The bacteriophage therapy is an effective antimicrobial approach with potentially important applications in medicine and biotechnology which can be seen as an additional string in the bow. Emerging drug resistant bacteria in aquaculture industry due to unrestricted use of antibiotics warrants more sustainable and environmental friendly strategies for controlling fish infections. The isolated bacteria from fish lesions was characterised based on isolation on selective and differential medium like Pseudomonas agar, gram staining, biochemical tests and 16SrRNA sequencing. The metallo-beta-lactamase (MBL) producing bacterial isolate was evaluated using Imipenem - Ethylenediaminetetraacetic acid (EDTA) disk method. The specific bacteriophage was isolated and concentrated using coal bed developed in our lab at CSIR-NEERI. The isolated and enriched bacteriophage was characterised by nucleotide sequencing and electron microscopy. The phage therapy was applied for treating ulcerative lesion in fish. Results The pathogenic bacterium responsible for causing ulcerative lesions in catfish species (Clarias gariepinus) was identified as Pseudomonas aeruginosa. One out of twenty P. aeruginosa isolate showing multi drug resistance (MDR) was incidentally found to be MBL producing as determined by Imipenem-EDTA disk method. The phage therapy effectively cured the ulcerative lesions of the infected fish in 8–10 days of treatment, with a sevenfold reduction of the lesion with untreated infection control. Conclusion Bacteriophage therapy can have potential applications soon as an alternative or as a complement to antibiotic treatment in the aquaculture. We present bacteriophage therapy as a treatment method for controlling MDR P. aeruginosa infection in C. gariepinus. To the best of our knowledge this is a first report of application of phage therapy against MBL producing P. aeruginosa isolated from aquatic ecosystem. PMID:24369750

Novel bacteriophage therapy for controlling metallo-beta-lactamase producing Pseudomonas aeruginosa infection in catfish.

PubMed

Khairnar, Krishna; Raut, Mahendra P; Chandekar, Rajshree H; Sanmukh, Swapnil G; Paunikar, Waman N

2013-12-26

The bacteriophage therapy is an effective antimicrobial approach with potentially important applications in medicine and biotechnology which can be seen as an additional string in the bow. Emerging drug resistant bacteria in aquaculture industry due to unrestricted use of antibiotics warrants more sustainable and environmental friendly strategies for controlling fish infections.The isolated bacteria from fish lesions was characterised based on isolation on selective and differential medium like Pseudomonas agar, gram staining, biochemical tests and 16SrRNA sequencing. The metallo-beta-lactamase (MBL) producing bacterial isolate was evaluated using Imipenem - Ethylenediaminetetraacetic acid (EDTA) disk method. The specific bacteriophage was isolated and concentrated using coal bed developed in our lab at CSIR-NEERI. The isolated and enriched bacteriophage was characterised by nucleotide sequencing and electron microscopy. The phage therapy was applied for treating ulcerative lesion in fish. The pathogenic bacterium responsible for causing ulcerative lesions in catfish species (Clarias gariepinus) was identified as Pseudomonas aeruginosa. One out of twenty P. aeruginosa isolate showing multi drug resistance (MDR) was incidentally found to be MBL producing as determined by Imipenem-EDTA disk method. The phage therapy effectively cured the ulcerative lesions of the infected fish in 8-10 days of treatment, with a sevenfold reduction of the lesion with untreated infection control. Bacteriophage therapy can have potential applications soon as an alternative or as a complement to antibiotic treatment in the aquaculture. We present bacteriophage therapy as a treatment method for controlling MDR P. aeruginosa infection in C. gariepinus. To the best of our knowledge this is a first report of application of phage therapy against MBL producing P. aeruginosa isolated from aquatic ecosystem.

Toward Balance Recovery With Leg Prostheses Using Neuromuscular Model Control

PubMed Central

Geyer, Hartmut

2016-01-01

Objective Lower limb amputees are at high risk of falling as current prosthetic legs provide only limited functionality for recovering balance after unexpected disturbances. For instance, the most established control method used on powered leg prostheses tracks local joint impedance functions without taking the global function of the leg in balance recovery into account. Here we explore an alternative control policy for powered transfemoral prostheses that considers the global leg function and is based on a neuromuscular model of human locomotion. Methods We adapt this model to describe and simulate an amputee walking with a powered prosthesis using the proposed control, and evaluate the gait robustness when confronted with rough ground and swing leg disturbances. We then implement and partially evaluate the resulting controller on a leg prosthesis prototype worn by a non-amputee user. Results In simulation, the proposed prosthesis control leads to gaits that are more robust than those obtained by the impedance control method. The initial hardware experiments with the prosthesis prototype show that the proposed control reproduces normal walking patterns qualitatively and effectively responds to disturbances in early and late swing. However, the response to mid-swing disturbances neither replicates human responses nor averts falls. Conclusions The neuromuscular model control is a promising alternative to existing prosthesis controls, although further research will need to improve on the initial implementation and determine how well these results transfer to amputee gait. Significance This work provides a potential avenue for future development of control policies that help improve amputee balance recovery. PMID:26315935

Fast and Accurate Microplate Method (Biolog MT2) for Detection of Fusarium Fungicides Resistance/Sensitivity.

PubMed

Frąc, Magdalena; Gryta, Agata; Oszust, Karolina; Kotowicz, Natalia

2016-01-01

The need for finding fungicides against Fusarium is a key step in the chemical plant protection and using appropriate chemical agents. Existing, conventional methods of evaluation of Fusarium isolates resistance to fungicides are costly, time-consuming and potentially environmentally harmful due to usage of high amounts of potentially toxic chemicals. Therefore, the development of fast, accurate and effective detection methods for Fusarium resistance to fungicides is urgently required. MT2 microplates (Biolog(TM)) method is traditionally used for bacteria identification and the evaluation of their ability to utilize different carbon substrates. However, to the best of our knowledge, there is no reports concerning the use of this technical tool to determine fungicides resistance of the Fusarium isolates. For this reason, the objectives of this study are to develop a fast method for Fusarium resistance to fungicides detection and to validate the effectiveness approach between both traditional hole-plate and MT2 microplates assays. In presented study MT2 microplate-based assay was evaluated for potential use as an alternative resistance detection method. This was carried out using three commercially available fungicides, containing following active substances: triazoles (tebuconazole), benzimidazoles (carbendazim) and strobilurins (azoxystrobin), in six concentrations (0, 0.0005, 0.005, 0.05, 0.1, 0.2%), for nine selected Fusarium isolates. In this study, the particular concentrations of each fungicides was loaded into MT2 microplate wells. The wells were inoculated with the Fusarium mycelium suspended in PM4-IF inoculating fluid. Before inoculation the suspension was standardized for each isolates into 75% of transmittance. Traditional hole-plate method was used as a control assay. The fungicides concentrations in control method were the following: 0, 0.0005, 0.005, 0.05, 0.5, 1, 2, 5, 10, 25, and 50%. Strong relationships between MT2 microplate and traditional hole-plate methods were observed regarding to the detection of Fusarium resistance to various fungicides and their concentrations. The tebuconazole was most potent, providing increased efficiency in the growth inhibition of all tested isolates. Almost all among tested isolates were resistant to azoxystrobin-based fungicide. Overall, the MT2 microplates method was effective and timesaving, alternative method for determining Fusarium resistance/sensitivity to fungicides, compering to traditional hole-plate approach.

Fast and Accurate Microplate Method (Biolog MT2) for Detection of Fusarium Fungicides Resistance/Sensitivity

PubMed Central

Frąc, Magdalena; Gryta, Agata; Oszust, Karolina; Kotowicz, Natalia

2016-01-01

The need for finding fungicides against Fusarium is a key step in the chemical plant protection and using appropriate chemical agents. Existing, conventional methods of evaluation of Fusarium isolates resistance to fungicides are costly, time-consuming and potentially environmentally harmful due to usage of high amounts of potentially toxic chemicals. Therefore, the development of fast, accurate and effective detection methods for Fusarium resistance to fungicides is urgently required. MT2 microplates (BiologTM) method is traditionally used for bacteria identification and the evaluation of their ability to utilize different carbon substrates. However, to the best of our knowledge, there is no reports concerning the use of this technical tool to determine fungicides resistance of the Fusarium isolates. For this reason, the objectives of this study are to develop a fast method for Fusarium resistance to fungicides detection and to validate the effectiveness approach between both traditional hole-plate and MT2 microplates assays. In presented study MT2 microplate-based assay was evaluated for potential use as an alternative resistance detection method. This was carried out using three commercially available fungicides, containing following active substances: triazoles (tebuconazole), benzimidazoles (carbendazim) and strobilurins (azoxystrobin), in six concentrations (0, 0.0005, 0.005, 0.05, 0.1, 0.2%), for nine selected Fusarium isolates. In this study, the particular concentrations of each fungicides was loaded into MT2 microplate wells. The wells were inoculated with the Fusarium mycelium suspended in PM4-IF inoculating fluid. Before inoculation the suspension was standardized for each isolates into 75% of transmittance. Traditional hole-plate method was used as a control assay. The fungicides concentrations in control method were the following: 0, 0.0005, 0.005, 0.05, 0.5, 1, 2, 5, 10, 25, and 50%. Strong relationships between MT2 microplate and traditional hole-plate methods were observed regarding to the detection of Fusarium resistance to various fungicides and their concentrations. The tebuconazole was most potent, providing increased efficiency in the growth inhibition of all tested isolates. Almost all among tested isolates were resistant to azoxystrobin-based fungicide. Overall, the MT2 microplates method was effective and timesaving, alternative method for determining Fusarium resistance/sensitivity to fungicides, compering to traditional hole-plate approach. PMID:27092136

Implementation of a Surface Electromyography-Based Upper Extremity Exoskeleton Controller Using Learning from Demonstration.

PubMed

Siu, Ho Chit; Arenas, Ana M; Sun, Tingxiao; Stirling, Leia A

2018-02-05

Upper-extremity exoskeletons have demonstrated potential as augmentative, assistive, and rehabilitative devices. Typical control of upper-extremity exoskeletons have relied on switches, force/torque sensors, and surface electromyography (sEMG), but these systems are usually reactionary, and/or rely on entirely hand-tuned parameters. sEMG-based systems may be able to provide anticipatory control, since they interface directly with muscle signals, but typically require expert placement of sensors on muscle bodies. We present an implementation of an adaptive sEMG-based exoskeleton controller that learns a mapping between muscle activation and the desired system state during interaction with a user, generating a personalized sEMG feature classifier to allow for anticipatory control. This system is robust to novice placement of sEMG sensors, as well as subdermal muscle shifts. We validate this method with 18 subjects using a thumb exoskeleton to complete a book-placement task. This learning-from-demonstration system for exoskeleton control allows for very short training times, as well as the potential for improvement in intent recognition over time, and adaptation to physiological changes in the user, such as those due to fatigue.

Implementation of a Surface Electromyography-Based Upper Extremity Exoskeleton Controller Using Learning from Demonstration

PubMed Central

Arenas, Ana M.; Sun, Tingxiao

2018-01-01

Upper-extremity exoskeletons have demonstrated potential as augmentative, assistive, and rehabilitative devices. Typical control of upper-extremity exoskeletons have relied on switches, force/torque sensors, and surface electromyography (sEMG), but these systems are usually reactionary, and/or rely on entirely hand-tuned parameters. sEMG-based systems may be able to provide anticipatory control, since they interface directly with muscle signals, but typically require expert placement of sensors on muscle bodies. We present an implementation of an adaptive sEMG-based exoskeleton controller that learns a mapping between muscle activation and the desired system state during interaction with a user, generating a personalized sEMG feature classifier to allow for anticipatory control. This system is robust to novice placement of sEMG sensors, as well as subdermal muscle shifts. We validate this method with 18 subjects using a thumb exoskeleton to complete a book-placement task. This learning-from-demonstration system for exoskeleton control allows for very short training times, as well as the potential for improvement in intent recognition over time, and adaptation to physiological changes in the user, such as those due to fatigue. PMID:29401754

Decision support for evidence-based integration of disease control: A proof of concept for malaria and schistosomiasis

PubMed Central

Graeden, Ellie; Kerr, Justin; Sorrell, Erin M.; Katz, Rebecca

2018-01-01

Managing infectious disease requires rapid and effective response to support decision making. The decisions are complex and require understanding of the diseases, disease intervention and control measures, and the disease-relevant characteristics of the local community. Though disease modeling frameworks have been developed to address these questions, the complexity of current models presents a significant barrier to community-level decision makers in using the outputs of the most scientifically robust methods to support pragmatic decisions about implementing a public health response effort, even for endemic diseases with which they are already familiar. Here, we describe the development of an application available on the internet, including from mobile devices, with a simple user interface, to support on-the-ground decision-making for integrating disease control programs, given local conditions and practical constraints. The model upon which the tool is built provides predictive analysis for the effectiveness of integration of schistosomiasis and malaria control, two diseases with extensive geographical and epidemiological overlap, and which result in significant morbidity and mortality in affected regions. Working with data from countries across sub-Saharan Africa and the Middle East, we present a proof-of-principle method and corresponding prototype tool to provide guidance on how to optimize integration of vertical disease control programs. This method and tool demonstrate significant progress in effectively translating the best available scientific models to support practical decision making on the ground with the potential to significantly increase the efficacy and cost-effectiveness of disease control. Author summary Designing and implementing effective programs for infectious disease control requires complex decision-making, informed by an understanding of the diseases, the types of disease interventions and control measures available, and the disease-relevant characteristics of the local community. Though disease modeling frameworks have been developed to address these questions and support decision-making, the complexity of current models presents a significant barrier to on-the-ground end users. The picture is further complicated when considering approaches for integration of different disease control programs, where co-infection dynamics, treatment interactions, and other variables must also be taken into account. Here, we describe the development of an application available on the internet with a simple user interface, to support on-the-ground decision-making for integrating disease control, given local conditions and practical constraints. The model upon which the tool is built provides predictive analysis for the effectiveness of integration of schistosomiasis and malaria control, two diseases with extensive geographical and epidemiological overlap. This proof-of-concept method and tool demonstrate significant progress in effectively translating the best available scientific models to support pragmatic decision-making on the ground, with the potential to significantly increase the impact and cost-effectiveness of disease control. PMID:29649260

Acoustic Streaming in Microgravity: Flow Stability and Heat Transfer Enhancement

NASA Technical Reports Server (NTRS)

Trinh, E. H.

1999-01-01

Experimental results are presented for drops and bubbles levitated in a liquid host, with particular attention given to the effect of shape oscillations and capillary waves on the local flow fields. Some preliminary results are also presented on the use of streaming flows for the control of evaporation rate and rotation of electrostatically levitated droplets in 1 g. The results demonstrate the potential for the technological application of acoustic methods to active control of forced convection in microgravity.

[Predacious nematode-destroying fungi].

PubMed

Czygier, M; Boguś, M I

2001-01-01

Gastrointestinal nematodes are considered a serious economic problem affecting the livestock industry around the world. Current methods of their control, relaying mainly on organic drugs, are not sustainable because parasites develop resistance to anthelmintic and bacause of increasing public concern about chemicals residues in livestock products and environment. Nematode-trapping fungi offer a very promissing, nonchemotherapeutic approach to nematode parasite control. Their potential in preventing nematodosis is well documented. In this paper we outline the present knowlege on mechanisms involved in trapping and killing nematodes by the predacious nematode-destroying fungi.

Taking a Bite out of Malaria: Controlled Human Malaria Infection by Needle and Syringe

DTIC Science & Technology

2013-01-01

sporozoites (PfSPZ Challenge).1 Because of the potential of this “challenge in a bottle” to standardize and dramatically expand the use of controlled human...to CHMI5,6 since CHMI using mosquitoes that had fed on in vitro cultures of P. falciparum was introduced in 1986.14 Investigators frommultiple...conduct of CHMI and a second document for the microscopy methods used to determine the patency endpoint.15 Nevertheless, CHMI based upon the bites of

Overview of Considerations in Assessing the Biomass Potential of Army Installations.

DTIC Science & Technology

1981-08-01

stage. Will the species grow well in poor soils and on harsh, open sites? Trees that met these standards were then grouped according to their...frequency of fire, (2) reduces the need of fire control methods such as controlled burns, and (3) makes site preparation easier.21 Whole-tree chipping...the "aesthetic" value of the stand is increased.22 The negative effect most often thought to occur with whole-tree chipping is loss of soil nutrients

Limited Qualities Evaluation of Longitudinal Flight Control Systems Designed Using Multiobjective Control Design Techniques (HAVE INFINITY II)

DTIC Science & Technology

1998-06-01

analytical phase of this research. Finally, the mixed H2/H-Infinity method optimally tradeoff the different benefits offered by the separate H2 and H...potential benefits of the multiobjective design techniques used. Due to the HAVE INFINITY I test results, AFIT made the decision to continue the...sensitivity and complimentary sensitivity weighting, and a mixed H2/H-Infinity design that compromised the benefits of both design techniques optimally. The

The Arms Control and Crisis Management Potential of the Proposed International Satellite Monitoring Agency (ISMA)

DTIC Science & Technology

1984-12-01

unbiased scientific method , is widespread in the West. This is particularly true of the two arms control functions to which an ISMA would contribute...Elizabeth Young (Lord and Lady Kennett), Neitber Red Nor Dead:_ The Case for Dis• aumAmjeif, Social Democratic Party (SDP), Open Forum Paper No. 2...in the national interest. The Soviet Union is not the first, and is unlikely to be the last, country to adopt a . narrow, constructionist approach to

3DD - Three Dimensional Disposal of Spent Nuclear Fuel - 12449

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dvorakova, Marketa; Slovak, Jiri

2012-07-01

Three dimensional disposal is being considered as a way in which to store long-term spent nuclear fuel in underground disposal facilities in the Czech Republic. This method involves a combination of the two most common internationally recognised disposal methods in order to practically apply the advantages of both whilst, at the same time, eliminating their weaknesses; the method also allows easy removal in case of potential re-use. The proposed method for the disposal of spent nuclear fuel will reduce the areal requirements of future deep geological repositories by more than 30%. It will also simplify the container handling process bymore » using gravitational forces in order to meet requirements concerning the controllability of processes and ensuring operational and nuclear safety. With regard to the issue of the efficient potential removal of waste containers, this project offers an ingenious solution which does not disrupt the overall stability of the original disposal complex. (authors)« less

Investigation for Molecular Attraction Impact Between Contacting Surfaces in Micro-Gears

NASA Astrophysics Data System (ADS)

Yang, Ping; Li, Xialong; Zhao, Yanfang; Yang, Haiying; Wang, Shuting; Yang, Jianming

2013-10-01

The aim of this research work is to provide a systematic method to perform molecular attraction impact between contacting surfaces in micro-gear train. This method is established by integrating involute profile analysis and molecular dynamics simulation. A mathematical computation of micro-gear involute is presented based on geometrical properties, Taylor expression and Hamaker assumption. In the meantime, Morse potential function and the cut-off radius are introduced with a molecular dynamics simulation. So a hybrid computational method for the Van Der Waals force between the contacting faces in micro-gear train is developed. An example is illustrated to show the performance of this method. The results show that the change of Van Der Waals force in micro-gear train has a nonlinear characteristic with parameters change such as the modulus of the gear and the tooth number of gear etc. The procedure implies a potential feasibility that we can control the Van Der Waals force by adjusting the manufacturing parameters for gear train design.