Linear segmentation algorithm for detecting layer boundary with lidar.

PubMed

Mao, Feiyue; Gong, Wei; Logan, Timothy

2013-11-04

The automatic detection of aerosol- and cloud-layer boundary (base and top) is important in atmospheric lidar data processing, because the boundary information is not only useful for environment and climate studies, but can also be used as input for further data processing. Previous methods have demonstrated limitations in defining the base and top, window-size setting, and have neglected the in-layer attenuation. To overcome these limitations, we present a new layer detection scheme for up-looking lidars based on linear segmentation with a reasonable threshold setting, boundary selecting, and false positive removing strategies. Preliminary results from both real and simulated data show that this algorithm cannot only detect the layer-base as accurate as the simple multi-scale method, but can also detect the layer-top more accurately than that of the simple multi-scale method. Our algorithm can be directly applied to uncalibrated data without requiring any additional measurements or window size selections.

3D change detection in staggered voxels model for robotic sensing and navigation

NASA Astrophysics Data System (ADS)

Liu, Ruixu; Hampshire, Brandon; Asari, Vijayan K.

2016-05-01

3D scene change detection is a challenging problem in robotic sensing and navigation. There are several unpredictable aspects in performing scene change detection. A change detection method which can support various applications in varying environmental conditions is proposed. Point cloud models are acquired from a RGB-D sensor, which provides the required color and depth information. Change detection is performed on robot view point cloud model. A bilateral filter smooths the surface and fills the holes as well as keeps the edge details on depth image. Registration of the point cloud model is implemented by using Random Sample Consensus (RANSAC) algorithm. It uses surface normal as the previous stage for the ground and wall estimate. After preprocessing the data, we create a point voxel model which defines voxel as surface or free space. Then we create a color model which defines each voxel that has a color by the mean of all points' color value in this voxel. The preliminary change detection is detected by XOR subtract on the point voxel model. Next, the eight neighbors for this center voxel are defined. If they are neither all `changed' voxels nor all `no changed' voxels, a histogram of location and hue channel color is estimated. The experimental evaluations performed to evaluate the capability of our algorithm show promising results for novel change detection that indicate all the changing objects with very limited false alarm rate.

Fundamental limits of measurement in telecommunications: Experimental and modeling studies in a test optical network on proposal for the reform of telecommunication quantitations

NASA Astrophysics Data System (ADS)

Egan, James; McMillan, Normal; Denieffe, David

2011-08-01

Proposals for a review of the limits of measurement for telecommunications are made. The measures are based on adapting work from the area of chemical metrology for the field of telecommunications. Currie has introduced recommendations for defining the limits of measurement in chemical metrology and has identified three key fundamental limits of measurement. These are the critical level, the detection limit and the determination limit. Measurements on an optical system are used to illustrate the utility of these measures and discussion is given into the advantages of using these fundamental quantitations over existing methods.

Determination of thiopental in urine sample with high-performance liquid chromatography using iodine-azide reaction as a postcolumn detection system.

PubMed

Zakrzewski, Robert; Ciesielski, Witold

2005-09-25

The reaction between iodine and azide ions induced by thiopental was utilized as a postcolumn reaction for chromatographic determination of thiopental. The method is based on the separation of thiopental on an Nova-Pak CN HP column with an acetonitrile-aqueous solution of sodium azide as a mobile phase, followed by spectrophotometric measurement of the residual iodine (lambda=350 nm) from the postcolumn iodine-azide reaction induced by thiopental after mixing an iodine solution containing iodide ions with the column effluent containing azide ions and thiopental. Chromatograms obtained for thiopental showed negative peaks as a result of the decrease in background absorbance. The detection limit (defined as S/N=3) was 20 nM (0.4 pmol injected amount) for thiopental. Calibration graphs, plotted as peak area versus concentrations, were linear from 40 nM. The elaborated method was applied to determine thiopental in urine samples. The detection limit (defined as S/N=3) was 0.025 nmol/ml urine. Calibration graphs, plotted as peak area versus concentrations, were linear from 0.05 nmol/ml urine. Authentic urine samples were analyzed, thiopental was determined at nmol/ml urine level.

Stability Limits of Circumbinary Planets: Is There a Pile-up in the Kepler CBPs?

NASA Astrophysics Data System (ADS)

Quarles, B.; Satyal, S.; Kostov, V.; Kaib, N.; Haghighipour, N.

2018-04-01

The stability limit for circumbinary planets (CBPs) is not well defined and can depend on initial parameters defining either the planetary orbit and/or the inner binary orbit. We expand on the work of Holman & Wiegert (1999) to develop numerical tools for quick, easy, and accurate determination of the stability limit. The results of our simulations, as well as our numerical tools, are available to the community through Zenodo and GitHub, respectively. We employ a grid interpolation method based on ∼150 million full N-body simulations of initially circular, coplanar systems and compare to the nine known Kepler CBP systems. Using a formalism from planet packing studies, we find that 55% of the Kepler CBP systems allow for an additional equal-mass planet to potentially exist on an interior orbit relative to the observed planet. Therefore, we do not find strong evidence for a pile-up in the Kepler CBP systems and more detections are needed to adequately characterize the formation mechanisms for the CBP population. Observations from the Transiting Exoplanet Survey Satellite are expected to substantially increase the number of detections using the unique geometry of CBP systems, where multiple transits can occur during a single conjunction.

Limits of linearity and detection for some drugs of abuse.

PubMed

Needleman, S B; Romberg, R W

1990-01-01

The limits of linearity (LOL) and detection (LOD) are important factors in establishing the reliability of an analytical procedure for accurately assaying drug concentrations in urine specimens. Multiple analyses of analyte over an extended range of concentrations provide a measure of the ability of the analytical procedure to correctly identify known quantities of drug in a biofluid matrix. Each of the seven drugs of abuse gives linear analytical responses from concentrations at or near their LOD to concentrations several-fold higher than those generally encountered in the drug screening laboratory. The upper LOL exceeds the Department of Navy (DON) cutoff values by factors of approximately 2 to 160. The LOD varies from 0.4 to 5.0% of the DON cutoff value for each drug. The limit of quantitation (LOQ) is calculated as the LOD + 7 SD. The range for LOL is greater for drugs analyzed with deuterated internal standards compared with those using conventional internal standards. For THC acid, cocaine, PCP, and morphine, LOLs are 8 to 160-fold greater than the defined cutoff concentrations. For the other drugs, the LOL's are only 2 to 4-fold greater than the defined cutoff concentrations.

Modeling of a Single-Notch Microfiber Coupler for High-Sensitivity and Low Detection-Limit Refractive Index Sensing.

PubMed

Zhang, Jiali; Shi, Lei; Zhu, Song; Xu, Xinbiao; Zhang, Xinliang

2016-05-11

A highly sensitive refractive index sensor with low detection limit based on an asymmetric optical microfiber coupler is proposed. It is composed of a silica optical microfiber and an As₂Se₃ optical microfiber. Due to the asymmetry of the microfiber materials, a single-notch transmission spectrum is demonstrated by the large refractive index difference between the two optical microfibers. Compared with the symmetric coupler, the bandwidth of the asymmetric structure is over one order of magnitude narrower than that of the former. Therefore, the asymmetric optical microfiber coupler based sensor can reach over one order of magnitude smaller detection limit, which is defined as the minimal detectable refractive index change caused by the surrounding analyte. With the advantage of large evanescent field, the results also show that a sensitivity of up to 3212 nm per refractive index unit with a bandwidth of 12 nm is achieved with the asymmetric optical microfiber coupler. Furthermore, a maximum sensitivity of 4549 nm per refractive index unit can be reached while the radii of the silica optical microfiber and As₂Se₃ optical microfiber are 0.5 μm and a 0.128 μm, respectively. This sensor component may have important potential for low detection-limit physical and biochemical sensing applications.

Automated detection of diabetic retinopathy: barriers to translation into clinical practice.

PubMed

Abramoff, Michael D; Niemeijer, Meindert; Russell, Stephen R

2010-03-01

Automated identification of diabetic retinopathy (DR), the primary cause of blindness and visual loss for those aged 18-65 years, from color images of the retina has enormous potential to increase the quality, cost-effectiveness and accessibility of preventative care for people with diabetes. Through advanced image analysis techniques, retinal images are analyzed for abnormalities that define and correlate with the severity of DR. Translating automated DR detection into clinical practice will require surmounting scientific and nonscientific barriers. Scientific concerns, such as DR detection limits compared with human experts, can be studied and measured. Ethical, legal and political issues can be addressed, but are difficult or impossible to measure. The primary objective of this review is to survey the methods, potential benefits and limitations of automated detection in order to better manage translation into clinical practice, based on extensive experience with the systems we have developed.

Detection method of flexion relaxation phenomenon based on wavelets for patients with low back pain

NASA Astrophysics Data System (ADS)

Nougarou, François; Massicotte, Daniel; Descarreaux, Martin

2012-12-01

The flexion relaxation phenomenon (FRP) can be defined as a reduction or silence of myoelectric activity of the lumbar erector spinae muscle during full trunk flexion. It is typically absent in patients with chronic low back pain (LBP). Before any broad clinical utilization of this neuromuscular response can be made, effective, standardized, and accurate methods of identifying FRP limits are needed. However, this phenomenon is clearly more difficult to detect for LBP patients than for healthy patients. The main goal of this study is to develop an automated method based on wavelet transformation that would improve time point limits detection of surface electromyography signals of the FRP in case of LBP patients. Conventional visual identification and proposed automated methods of time point limits detection of relaxation phase were compared on experimental data using criteria of accuracy and repeatability based on physiological properties. The evaluation demonstrates that the use of wavelet transform (WT) yields better results than methods without wavelet decomposition. Furthermore, methods based on wavelet per packet transform are more effective than algorithms employing discrete WT. Compared to visual detection, in addition to demonstrating an obvious saving of time, the use of wavelet per packet transform improves the accuracy and repeatability in the detection of the FRP limits. These results clearly highlight the value of the proposed technique in identifying onset and offset of the flexion relaxation response in LBP subjects.

Malaria prevalence defined by microscopy, antigen detection, DNA amplification and total nucleic acid amplification in a malaria-endemic region during the peak malaria transmission season.

PubMed

Waitumbi, John N; Gerlach, Jay; Afonina, Irina; Anyona, Samuel B; Koros, Joseph N; Siangla, Joram; Ankoudinova, Irina; Singhal, Mitra; Watts, Kate; Polhemus, Mark E; Vermeulen, Nicolaas M; Mahoney, Walt; Steele, Matt; Domingo, Gonzalo J

2011-07-01

To determine the malaria prevalence by microscopy, antigen detection and nucleic acid detection in a defined subpopulation in a Plasmodium falciparum-endemic region during the peak transmission season. Blood specimens were collected in a cross-sectional study involving children aged 5-10 years (n = 195) presenting with acute fever to two clinics in Western Kenya. All specimens underwent microscopy, HRP2 and aldolase antigen detection by enzyme immunoassay (EIA), parasite-specific DNA and total nucleic acid (RNA and DNA) by real-time PCR (qPCR) and reverse-transcriptase PCR (qRT-PCR). Microscopy detected 65/195 cases of malaria infection [95% confidence interval (CI) 52-78]. HRP2 and aldolase EIA had similar sensitivity levels detecting antigen in 65/195 (95% CI, 52-78) and 57/195 (95% CI, 45-70) cases. Discordants in antigen detection vs. microscopy occurred at <470 parasites/μl and <4900 parasites/μl for HRP2 and aldolase, respectively. Detection of total nucleic acid allowed a 3 log lower limit of detection than just DNA detection by real-time PCR in vitro. In clinical specimens, 114/195 (95% CI, 100-127) were qPCR positive (DNA), and 187/195 (95% CI, 179-191) were qRT-PCR positive (DNA plus RNA). The prevalence of submicroscopic malaria infection was significantly higher when detecting total nucleic acid than just DNA in this outpatient population during the high transmission season. Defining standards for submicroscopic infection will be important for control programmes, diagnostics development efforts and molecular epidemiology studies. © 2011 Blackwell Publishing Ltd.

Plasmonic trace sensing below the photon shot noise limit

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

Pooser, Raphael C.; Lawrie, Benjamin J.

Plasmonic sensors are important detectors of biochemical trace compounds, but those that utilize optical readout are approaching their absolute limits of detection as defined by the Heisenberg uncertainty principle in both differential intensity and phase readout. However, the use of more general minimum uncertainty states in the form of squeezed light can push the noise floor in these sensors below the shot noise limit (SNL) in one analysis variable at the expense of another. Here, we demonstrate a quantum plasmonic sensor whose noise floor is reduced below the SNL in order to perform index of refraction measurements with sensitivities unobtainablemore » with classical plasmonic sensors. The increased signal-to-noise ratio can result in faster detection of analyte concentrations that were previously lost in the noise. As a result, these benefits are the hallmarks of a sensor exploiting quantum readout fields in order to manipulate the limits of the Heisenberg uncertainty principle.« less

Plasmonic trace sensing below the photon shot noise limit

DOE PAGES

Pooser, Raphael C.; Lawrie, Benjamin J.

2015-12-09

Plasmonic sensors are important detectors of biochemical trace compounds, but those that utilize optical readout are approaching their absolute limits of detection as defined by the Heisenberg uncertainty principle in both differential intensity and phase readout. However, the use of more general minimum uncertainty states in the form of squeezed light can push the noise floor in these sensors below the shot noise limit (SNL) in one analysis variable at the expense of another. Here, we demonstrate a quantum plasmonic sensor whose noise floor is reduced below the SNL in order to perform index of refraction measurements with sensitivities unobtainablemore » with classical plasmonic sensors. The increased signal-to-noise ratio can result in faster detection of analyte concentrations that were previously lost in the noise. As a result, these benefits are the hallmarks of a sensor exploiting quantum readout fields in order to manipulate the limits of the Heisenberg uncertainty principle.« less

Optical properties of materials at low temperature and their application to optical detection

NASA Technical Reports Server (NTRS)

Hartwig, W. H.; Tarchi, A. A.

1972-01-01

A lumped model to represent the photodielectric effect is developed. An analog simulation for a sample in a microwave cavity with a static magnetic field is developed. A system to measure continuously the PDE is analyzed. A performance factor to compared PD detectors versus ac photoconductors is computed. The operating conditions are defined for the appropriate noise conditions. The detectivity of the detector is found to be limited by the semiconductor sample noise.

Contingent capture of involuntary visual attention interferes with detection of auditory stimuli

PubMed Central

Kamke, Marc R.; Harris, Jill

2014-01-01

The involuntary capture of attention by salient visual stimuli can be influenced by the behavioral goals of an observer. For example, when searching for a target item, irrelevant items that possess the target-defining characteristic capture attention more strongly than items not possessing that feature. Such contingent capture involves a shift of spatial attention toward the item with the target-defining characteristic. It is not clear, however, if the associated decrements in performance for detecting the target item are entirely due to involuntary orienting of spatial attention. To investigate whether contingent capture also involves a non-spatial interference, adult observers were presented with streams of visual and auditory stimuli and were tasked with simultaneously monitoring for targets in each modality. Visual and auditory targets could be preceded by a lateralized visual distractor that either did, or did not, possess the target-defining feature (a specific color). In agreement with the contingent capture hypothesis, target-colored distractors interfered with visual detection performance (response time and accuracy) more than distractors that did not possess the target color. Importantly, the same pattern of results was obtained for the auditory task: visual target-colored distractors interfered with sound detection. The decrement in auditory performance following a target-colored distractor suggests that contingent capture involves a source of processing interference in addition to that caused by a spatial shift of attention. Specifically, we argue that distractors possessing the target-defining characteristic enter a capacity-limited, serial stage of neural processing, which delays detection of subsequently presented stimuli regardless of the sensory modality. PMID:24920945

Contingent capture of involuntary visual attention interferes with detection of auditory stimuli.

PubMed

Kamke, Marc R; Harris, Jill

2014-01-01

The involuntary capture of attention by salient visual stimuli can be influenced by the behavioral goals of an observer. For example, when searching for a target item, irrelevant items that possess the target-defining characteristic capture attention more strongly than items not possessing that feature. Such contingent capture involves a shift of spatial attention toward the item with the target-defining characteristic. It is not clear, however, if the associated decrements in performance for detecting the target item are entirely due to involuntary orienting of spatial attention. To investigate whether contingent capture also involves a non-spatial interference, adult observers were presented with streams of visual and auditory stimuli and were tasked with simultaneously monitoring for targets in each modality. Visual and auditory targets could be preceded by a lateralized visual distractor that either did, or did not, possess the target-defining feature (a specific color). In agreement with the contingent capture hypothesis, target-colored distractors interfered with visual detection performance (response time and accuracy) more than distractors that did not possess the target color. Importantly, the same pattern of results was obtained for the auditory task: visual target-colored distractors interfered with sound detection. The decrement in auditory performance following a target-colored distractor suggests that contingent capture involves a source of processing interference in addition to that caused by a spatial shift of attention. Specifically, we argue that distractors possessing the target-defining characteristic enter a capacity-limited, serial stage of neural processing, which delays detection of subsequently presented stimuli regardless of the sensory modality.

Trouble Brewing: Using Observations of Invariant Behavior to Detect Malicious Agency in Distributed Control Systems

NASA Astrophysics Data System (ADS)

McEvoy, Thomas Richard; Wolthusen, Stephen D.

Recent research on intrusion detection in supervisory data acquisition and control (SCADA) and DCS systems has focused on anomaly detection at protocol level based on the well-defined nature of traffic on such networks. Here, we consider attacks which compromise sensors or actuators (including physical manipulation), where intrusion may not be readily apparent as data and computational states can be controlled to give an appearance of normality, and sensor and control systems have limited accuracy. To counter these, we propose to consider indirect relations between sensor readings to detect such attacks through concurrent observations as determined by control laws and constraints.

The Changing Role of the Clinical Microbiology Laboratory in Defining Resistance in Gram-negatives.

PubMed

Endimiani, Andrea; Jacobs, Michael R

2016-06-01

The evolution of resistance in Gram-negatives has challenged the clinical microbiology laboratory to implement new methods for their detection. Multidrug-resistant strains present major challenges to conventional and new detection methods. More rapid pathogen identification and antimicrobial susceptibility testing have been developed for use directly on specimens, including fluorescence in situ hybridization tests, automated polymerase chain reaction systems, microarrays, mass spectroscopy, next-generation sequencing, and microfluidics. Review of these methods shows the advances that have been made in rapid detection of resistance in cultures, but limited progress in direct detection from specimens. Copyright © 2016 Elsevier Inc. All rights reserved.

Flexible shrink-induced high surface area electrodes for electrochemiluminescent sensing.

PubMed

Pegan, Jonathan D; Ho, Adrienne Y; Bachman, Mark; Khine, Michelle

2013-11-07

Photolithographically defined metallic thin film on commodity shrink-wrap is leveraged to create robust electrodes. By thermally shrinking the film, electrodes are reduced by 20× in footprint for improved resolution and conductivity with >600% enhancements in electrochemically active surface area; as electrochemiluminescent sensors, they demonstrate improved limits of detection.

Program SimAssem: software for simulating species assemblages and estimating species richness

Treesearch

Gordon C. Reese; Kenneth R. Wilson; Curtis H. Flather

2013-01-01

1. Species richness, the number of species in a defined area, is the most frequently used biodiversity measure. Despite its intuitive appeal and conceptual simplicity, species richness is often difficult to quantify, even in well surveyed areas, because of sampling limitations such as survey effort and species detection probability....

The Limits of Coding with Joint Constraints on Detected and Undetected Error Rates

NASA Technical Reports Server (NTRS)

Dolinar, Sam; Andrews, Kenneth; Pollara, Fabrizio; Divsalar, Dariush

2008-01-01

We develop a remarkably tight upper bound on the performance of a parameterized family of bounded angle maximum-likelihood (BA-ML) incomplete decoders. The new bound for this class of incomplete decoders is calculated from the code's weight enumerator, and is an extension of Poltyrev-type bounds developed for complete ML decoders. This bound can also be applied to bound the average performance of random code ensembles in terms of an ensemble average weight enumerator. We also formulate conditions defining a parameterized family of optimal incomplete decoders, defined to minimize both the total codeword error probability and the undetected error probability for any fixed capability of the decoder to detect errors. We illustrate the gap between optimal and BA-ML incomplete decoding via simulation of a small code.

A Matched Filter Technique for Slow Radio Transient Detection and First Demonstration with the Murchison Widefield Array

NASA Astrophysics Data System (ADS)

Feng, L.; Vaulin, R.; Hewitt, J. N.; Remillard, R.; Kaplan, D. L.; Murphy, Tara; Kudryavtseva, N.; Hancock, P.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Gaensler, B. M.; Greenhill, L. J.; Hazelton, B. J.; Johnston-Hollitt, M.; Lonsdale, C. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.

2017-03-01

Many astronomical sources produce transient phenomena at radio frequencies, but the transient sky at low frequencies (<300 MHz) remains relatively unexplored. Blind surveys with new wide-field radio instruments are setting increasingly stringent limits on the transient surface density on various timescales. Although many of these instruments are limited by classical confusion noise from an ensemble of faint, unresolved sources, one can in principle detect transients below the classical confusion limit to the extent that the classical confusion noise is independent of time. We develop a technique for detecting radio transients that is based on temporal matched filters applied directly to time series of images, rather than relying on source-finding algorithms applied to individual images. This technique has well-defined statistical properties and is applicable to variable and transient searches for both confusion-limited and non-confusion-limited instruments. Using the Murchison Widefield Array as an example, we demonstrate that the technique works well on real data despite the presence of classical confusion noise, sidelobe confusion noise, and other systematic errors. We searched for transients lasting between 2 minutes and 3 months. We found no transients and set improved upper limits on the transient surface density at 182 MHz for flux densities between ˜20 and 200 mJy, providing the best limits to date for hour- and month-long transients.

Market analysis of food products for detection of allergenic walnut (Juglans regia) and pecan (Carya illinoinensis) by real-time PCR.

PubMed

López-Calleja, Inés María; de la Cruz, Silvia; González, Isabel; García, Teresa; Martín, Rosario

2015-06-15

Two real-time polymerase chain reaction (PCR)-based assays for detection of walnut (Juglans regia) and pecan (Carya illinoinensis) traces in a wide range of processed foods are described here. The method consists on a real-time PCR assay targeting the ITS1 region, using a nuclease (TaqMan) probe labeled with FAM and BBQ. The method was positive for walnut and pecan respectively, and negative for all other heterologous plants and animals tested. Using a series of model samples with defined raw walnut in wheat flour and heat-treated walnut in wheat flour with a range of concentrations of 0.1-100,000 mg kg(-1), a practical detection limit of 0.1 mg kg(-1) of walnut content was estimated. Identical binary mixtures were done for pecan, reaching the same limit of detection of 0.1 mg kg(-1). The assay was successfully trialed on a total of 232 commercial foodstuffs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of single ion channel data incorporating time-interval omission and sampling

PubMed Central

The, Yu-Kai; Timmer, Jens

2005-01-01

Hidden Markov models are widely used to describe single channel currents from patch-clamp experiments. The inevitable anti-aliasing filter limits the time resolution of the measurements and therefore the standard hidden Markov model is not adequate anymore. The notion of time-interval omission has been introduced where brief events are not detected. The developed, exact solutions to this problem do not take into account that the measured intervals are limited by the sampling time. In this case the dead-time that specifies the minimal detectable interval length is not defined unambiguously. We show that a wrong choice of the dead-time leads to considerably biased estimates and present the appropriate equations to describe sampled data. PMID:16849220

Plasmodium vivax molecular diagnostics in community surveys: pitfalls and solutions.

PubMed

Gruenberg, Maria; Moniz, Clara Antunes; Hofmann, Natalie Ellen; Wampfler, Rahel; Koepfli, Cristian; Mueller, Ivo; Monteiro, Wuelton Marcelo; Lacerda, Marcus; de Melo, Gisely Cardoso; Kuehn, Andrea; Siqueira, Andre M; Felger, Ingrid

2018-01-30

A distinctive feature of Plasmodium vivax infections is the overall low parasite density in peripheral blood. Thus, identifying asymptomatic infected individuals in endemic communities requires diagnostic tests with high sensitivity. The detection limits of molecular diagnostic tests are primarily defined by the volume of blood analysed and by the copy number of the amplified molecular marker serving as the template for amplification. By using mitochondrial DNA as the multi-copy template, the detection limit can be improved more than tenfold, compared to standard 18S rRNA targets, thereby allowing detection of lower parasite densities. In a very low transmission area in Brazil, application of a mitochondrial DNA-based assay increased prevalence from 4.9 to 6.5%. The usefulness of molecular tests in malaria epidemiological studies is widely recognized, especially when precise prevalence rates are desired. Of concern, however, is the challenge of demonstrating test accuracy and quality control for samples with very low parasite densities. In this case, chance effects in template distribution around the detection limit constrain reproducibility. Rigorous assessment of false positive and false negative test results is, therefore, required to prevent over- or under-estimation of parasite prevalence in epidemiological studies or when monitoring interventions.

Perils of categorical thinking: "Oxic/anoxic" conceptual model in environmental remediation

USGS Publications Warehouse

Bradley, Paul M.

2012-01-01

Given ambient atmospheric oxygen concentrations of about 21 percent (by volume), the lower limit for reliable quantitation of dissolved oxygen concentrations in groundwater samples is in the range of 0.1–0.5 mg/L. Frameworks for assessing in situ redox condition are often applied using a simple two-category (oxic/anoxic) model of oxygen condition. The "oxic" category defines the environmental range in which dissolved oxygen concentrations are clearly expected to impact contaminant biodegradation, either by supporting aerobic biodegradation of electron-donor contaminants like petroleum hydrocarbons or by inhibiting anaerobic biodegradation of electron-acceptor contaminants like chloroethenes. The tendency to label the second category "anoxic" leads to an invalid assumption that oxygen is insignificant when, in fact, the dissolved oxygen concentration is less than detection but otherwise unknown. Expressing dissolved oxygen concentrations as numbers of molecules per volume, dissolved oxygen concentrations that fall below the 0.1 mg/L field detection limit range from 1 to 1017 molecules/L. In light of recent demonstrations of substantial oxygen-linked biodegradation of chloroethene contaminants at dissolved oxygen concentrations well below the 0.1–0.5 mg/L field detection limit, characterizing "less than detection" oxygen concentrations as "insignificant" is invalid.

Programmable and highly resolved in vitro detection of 5-methylcytosine by TALEs.

PubMed

Kubik, Grzegorz; Schmidt, Moritz J; Penner, Johanna E; Summerer, Daniel

2014-06-02

Gene expression is extensively regulated by specific patterns of genomic 5-methylcytosine (mC), but the ability to directly detect this modification at user-defined genomic loci is limited. One reason is the lack of molecules that discriminate between mC and cytosine (C) and at the same time provide inherent, programmable sequence-selectivity. Programmable transcription-activator-like effectors (TALEs) have been observed to exhibit mC-sensitivity in vivo, but to only a limited extent in vitro. We report an mC-detection assay based on TALE control of DNA replication that displays unexpectedly strong mC-discrimination ability in vitro. The status and level of mC modification at single positions in oligonucleotides can be determined unambiguously by this assay, independently of the overall target sequence. Moreover, discrimination is reliably observed for positions bound by N-terminal and central regions of TALEs. This indicates the wide scope and robustness of the approach for highly resolved mC detection and enabled the detection of a single mC in a large, eukaryotic genome. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Axillary, Oral and Rectal Routes of Temperature Measurement During Treatment of Acute Kawasaki Disease.

PubMed

Kanegaye, John T; Jones, Jefferson M; Burns, Jane C; Jain, Sonia; Sun, Xiaoying; Jimenez-Fernandez, Susan; Berry, Erika; Pancheri, Joan M; Jaggi, Preeti; Ramilo, Octavio; Tremoulet, Adriana H

2016-01-01

Important therapeutic decisions are made based on the presence or absence of fever in patients with Kawasaki disease (KD), yet no standard method or threshold exists for temperature measurement during the diagnosis and treatment of these patients. We sought to compare surface and internal (rectal or oral) routes of temperature measurement for the detection of fever as a marker of treatment resistance. From a randomized, placebo-controlled trial of infliximab as an adjunct to primary intravenous immunoglobulin treatment for acute KD, we collected concurrent (within 5 minutes) axillary and internal temperature measurements and performed receiver-operating characteristic and Bland-Altman analyses. We also determined the ability of surface temperatures to detect treatment resistance defined by internal temperature measurements. Among 452 oral-axillary and 439 rectal-axillary pairs from 159 patients, mean axillary temperatures were 0.25 and 0.43 °C lower than oral and rectal temperatures and had high receiver-operating characteristic areas under curves. However, axillary temperatures ≥ 38.0 °C had limited sensitivity to detect fever defined by internal temperatures. Axillary thresholds of 37.5 and 37.2 °C provided maximal sensitivity and specificity to detect oral and rectal temperatures ≥ 38.0 °C, respectively. Axillary temperatures are an insensitive metric for fevers defining treatment resistance. Clinical trials should adopt temperature measurement by the oral or rectal routes for adjudication of treatment resistance in KD.

Developing the Cleanliness Requirements for an Organic-detection Instrument MOMA-MS

NASA Technical Reports Server (NTRS)

Perry, Radford; Canham, John; Lalime, Erin

2015-01-01

The cleanliness requirements for an organic-detection instrument, like the Mars Organic Molecule Analyzer Mass Spectrometer (MOMA-MS), on a Planetary Protection Class IVb mission can be extremely stringent. These include surface molecular and particulate, outgassing, and bioburden. The prime contractor for the European Space Agencys ExoMars 2018 project, Thales Alenia Space Italy, provided requirements based on a standard, conservative approach of defining limits which yielded levels that are unverifiable by standard cleanliness verification methods. Additionally, the conservative method for determining contamination surface area uses underestimation while conservative bioburden surface area relies on overestimation, which results in inconsistencies for the normalized reporting. This presentation will provide a survey of the challenge to define requirements that can be reasonably verified and still remain appropriate to the core science of the ExoMars mission.

Disease management of dairy calves and heifers.

PubMed

McGuirk, Sheila M

2008-03-01

This article focuses on the most important diseases of dairy calves and heifers and presents clinical approaches that can improve detection, diagnosis, and treatment of herd-based problems. A systematic herd investigation strategy is pivotal to define the problems, understand important risk factors, develop a plan, and make recommendations for disease management accurately. A review of records, colostrum and feeding routines, housing and bedding management, routine procedures, vaccination, and treatment protocols begins the investigation and determines which diagnostic procedures and testing strategies are most useful. Disease management is most effective when the problem source is well defined and the exposure can be limited, calf immunity can be enhanced, or a combination of both. Screening examinations performed regularly or done at strategic time points improves detection of disease, can be used to monitor treatment outcomes, and can avoid disease outbreaks.

A radio monitoring survey of ultra-luminous X-ray sources

NASA Astrophysics Data System (ADS)

Körding, E.; Colbert, E.; Falcke, H.

2005-06-01

We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These sources are bright off-nuclear X-ray point sources with luminosities exceeding LX > 1039 erg s-1. A well-defined sample of the 9 nearest ULXs has been monitored eight times over 5 months with the Very Large Array in A and B configuration. Our limiting sensitivity is ≈0.15 mJy (4σ) for radio flares and ≈60 μJy for continuous emission. In M 82 two ULXs seem to have coincident compact radio sources, which are probably supernova remnants. No continuous or flaring radio emission has been detected from any other ULX. Thus, ULXs do not generally emit steady-state radio emission above radio powers of 1.5 × 1017 W/Hz. The non-detections of the continuous emission are consistent with beamed or unbeamed radio emission from accreting black holes of ≤ 103 M⊙ based on the radio/X-ray correlation. Other published radio detections (M 82, NGC 5408) are also discussed in this context. Both detections are significantly above our detection limit. If ULXs have flaring radio emission above 4 × 1017 W/Hz we can give an upper limit on the duty cycle of the flares of 6%. This upper limit is in agreement with the observed number of flares in Galactic radio transients. Additionally we present a yet unreported radio double structure in the nearby low-luminosity AGN NGC 4736.

Enhancing nuclear quadrupole resonance (NQR) signature detection leveraging interference suppression algorithms

NASA Astrophysics Data System (ADS)

DeBardelaben, James A.; Miller, Jeremy K.; Myrick, Wilbur L.; Miller, Joel B.; Gilbreath, G. Charmaine; Bajramaj, Blerta

2012-06-01

Nuclear quadrupole resonance (NQR) is a radio frequency (RF) magnetic spectroscopic technique that has been shown to detect and identify a wide range of explosive materials containing quadrupolar nuclei. The NQR response signal provides a unique signature of the material of interest. The signal is, however, very weak and can be masked by non-stationary RF interference (RFI) and thermal noise, limiting detection distance. In this paper, we investigate the bounds on the NQR detection range for ammonium nitrate. We leverage a low-cost RFI data acquisition system composed of inexpensive B-field sensing and commercial-off-the-shelf (COTS) software-defined radios (SDR). Using collected data as RFI reference signals, we apply adaptive filtering algorithms to mitigate RFI and enable NQR detection techniques to approach theoretical range bounds in tactical environments.

Threat detection of liquid explosives and precursors from their x-ray scattering pattern using energy dispersive detector technology

NASA Astrophysics Data System (ADS)

Kehres, Jan; Lyksborg, Mark; Olsen, Ulrik L.

2017-09-01

Energy dispersive X-ray diffraction (EDXRD) can be applied for identification of liquid threats in luggage scanning in security applications. To define the instrumental design, the framework for data reduction and analysis and test the performance of the threat detection in various scenarios, a flexible laboratory EDXRD test setup was build. A data set of overall 570 EDXRD spectra has been acquired for training and testing of threat identification algorithms. The EDXRD data was acquired with limited count statistics and at multiple detector angles and merged after correction and normalization. Initial testing of the threat detection algorithms with this data set indicate the feasibility of detection levels of > 95 % true positive with < 6 % false positive alarms.

Installation Restoration Program. Remedial Investigation Report: Minnesota Air National Guard Base Duluth International Airport, Duluth, Minnesota. Volume 6

DTIC Science & Technology

1990-01-01

reporting limit. Acceptable RPD in this case is defined as duplicate values within one detection limit of each other. I I I I I I i I i 2567I88-A1...analysis shois the :aboratory to be in ccn:rol. Results for Sa:Dle No. 88092.739 are reported on a wet weight basis, since percen:age moisture was...describes the remedial actions performed on sites confirmed to contain hazardous waste contamination which endangers the human health. The actions

Separation of paralytic shellfish poisoning toxins on Chromarods-SIII by thin-layer chromatography with the Iatroscan (mark 5) and flame thermionic detection.

PubMed

Indrasena, W M; Ackman, R G; Gill, T A

1999-09-10

Thin-layer chromatography (TLC) on Chromarods-SIII with the Iatroscan (Mark-5) and a flame thermionic detector (FTID) was used to develop a rapid method for the detection of paralytic shellfish poisoning (PSP) toxins. The effect of variation in hydrogen (H2) flow, air flow, scan time and detector current on the FTID peak response for both phosphatidylcholine (PC) and PSP were studied in order to define optimum detection conditions. A combination of hydrogen and air flow-rates of 50 ml/min and 1.5-2.0 l/min respectively, along with a scan time of 40 s/rod and detector current of 3.0 A (ampere) or above were found to yield the best results for the detection of PSP compounds. Increasing the detector current level to as high as 3.3 A gave about 130 times more FTID response than did flame ionization detection (FID), for PSP components. Quantities of standards as small as 1 ng neosaxitoxin (NEO), 5 ng saxitoxin (STX), 5 ng B1-toxins (B1), 2 ng gonyautoxin (GTX) 2/3, 6 ng GTX 1/4 and 6 ng C-toxins (C1/C2) could be detected with the FTID. The method detection limits for toxic shellfish tissues using the FTID were 0.4, 2.1, 0.8 and 2.5 micrograms per g tissue for GTX 2/3, STX, NEO and C toxins, respectively. The FTID response increased with increasing detector current and with increasing the scan time. Increasing hydrogen and air flow-rates resulted in decreasing sensitivity within defined limits. Numerous solvent systems were tested, and, solvent consisting of chloroform: methanol-water-acetic acid (30:50:8:2) could separate C toxins from GTX, which eluted ahead of NEO and STX. Accordingly, TLC/FTID with the Iatroscan (Mark-5) seems to be a promising, relatively inexpensive and rapid method of screening plant and animal tissues for PSP toxins.

Thermal Infrared Spectral Band Detection Limits for Unidentified Surface Materials

NASA Technical Reports Server (NTRS)

Kirkland, Laurel E.; Herr, Kenneth C.; Salisbury, John W.

2001-01-01

Infrared emission spectra recorded by airborne or satellite spectrometers can be searched for spectral features to determine the composition of rocks on planetary surfaces. Surface materials are identified by detections of characteristic spectral bands. We show how to define whether to accept an observed spectral feature as a detection when the target material is unknown. We also use remotely sensed spectra measured by the Thermal Emission Spectrometer (TES) and the Spatially Enhanced Broadband Array Spectrograph System to illustrate the importance of instrument parameters and surface properties on band detection limits and how the variation in signal-to-noise ratio with wavelength affects the bands that are most detectable for a given instrument. The spectrometer's sampling interval, spectral resolution, signal-to-noise ratio as a function of wavelength, and the sample's surface properties influence whether the instrument can detect a spectral feature exhibited by a material. As an example, in the 6-13 micrometer wavelength region, massive carbonates exhibit two bands: a very strong, broad feature at approximately 6.5 micrometers and a less intense, sharper band at approximately 11.25 micrometers. Although the 6.5-micrometer band is stronger and broader in laboratory-measured spectra, the 11.25-micrometer band will cause a more detectable feature in TES spectra.

Combustion diagnostic for active engine feedback control

DOEpatents

Green, Jr., Johney Boyd; Daw, Charles Stuart; Wagner, Robert Milton

2007-10-02

This invention detects the crank angle location where combustion switches from premixed to diffusion, referred to as the transition index, and uses that location to define integration limits that measure the portions of heat released during the combustion process that occur during the premixed and diffusion phases. Those integrated premixed and diffusion values are used to develop a metric referred to as the combustion index. The combustion index is defined as the integrated diffusion contribution divided by the integrated premixed contribution. As the EGR rate is increased enough to enter the low temperature combustion regime, PM emissions decrease because more of the combustion process is occurring over the premixed portion of the heat release rate profile and the diffusion portion has been significantly reduced. This information is used to detect when the engine is or is not operating in a low temperature combustion mode and provides that feedback to an engine control algorithm.

Terahertz Computed Tomography of NASA Thermal Protection System Materials

NASA Technical Reports Server (NTRS)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Sensor Data Qualification System (SDQS) Implementation Study

NASA Technical Reports Server (NTRS)

Wong, Edmond; Melcher, Kevin; Fulton, Christopher; Maul, William

2009-01-01

The Sensor Data Qualification System (SDQS) is being developed to provide a sensor fault detection capability for NASA s next-generation launch vehicles. In addition to traditional data qualification techniques (such as limit checks, rate-of-change checks and hardware redundancy checks), SDQS can provide augmented capability through additional techniques that exploit analytical redundancy relationships to enable faster and more sensitive sensor fault detection. This paper documents the results of a study that was conducted to determine the best approach for implementing a SDQS network configuration that spans multiple subsystems, similar to those that may be implemented on future vehicles. The best approach is defined as one that most minimizes computational resource requirements without impacting the detection of sensor failures.

An Energy-Based Approach for Detection and Characterization of Subtle Entities Within Laser Scanning Point-Clouds

NASA Astrophysics Data System (ADS)

Arav, Reuma; Filin, Sagi

2016-06-01

Airborne laser scans present an optimal tool to describe geomorphological features in natural environments. However, a challenge arises in the detection of such phenomena, as they are embedded in the topography, tend to blend into their surroundings and leave only a subtle signature within the data. Most object-recognition studies address mainly urban environments and follow a general pipeline where the data are partitioned into segments with uniform properties. These approaches are restricted to man-made domain and are capable to handle limited features that answer a well-defined geometric form. As natural environments present a more complex set of features, the common interpretation of the data is still manual at large. In this paper, we propose a data-aware detection scheme, unbound to specific domains or shapes. We define the recognition question as an energy optimization problem, solved by variational means. Our approach, based on the level-set method, characterizes geometrically local surfaces within the data, and uses these characteristics as potential field for minimization. The main advantage here is that it allows topological changes of the evolving curves, such as merging and breaking. We demonstrate the proposed methodology on the detection of collapse sinkholes.

Detection of argan oil adulteration with vegetable oils by high-performance liquid chromatography-evaporative light scattering detection.

PubMed

Salghi, Rachid; Armbruster, Wolfgang; Schwack, Wolfgang

2014-06-15

Triacylglycerol profiles were selected as indicator of adulteration of argan oils to carry out a rapid screening of samples for the evaluation of authenticity. Triacylglycerols were separated by high-performance liquid chromatography-evaporative light scattering detection. Different peak area ratios were defined to sensitively detect adulteration of argan oil with vegetable oils such as sunflower, soy bean, and olive oil up to the level of 5%. Based on four reference argan oils, mean limits of detection and quantitation were calculated to approximately 0.4% and 1.3%, respectively. Additionally, 19 more argan oil reference samples were analysed by high-performance liquid chromatography-refractive index detection, resulting in highly comparative results. The overall strategy demonstrated a good applicability in practise, and hence a high potential to be transferred to routine laboratories. Copyright © 2013 Elsevier Ltd. All rights reserved.

Detection limit for rate fluctuations in inhomogeneous Poisson processes

NASA Astrophysics Data System (ADS)

Shintani, Toshiaki; Shinomoto, Shigeru

2012-04-01

Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

Detection limit for rate fluctuations in inhomogeneous Poisson processes.

PubMed

Shintani, Toshiaki; Shinomoto, Shigeru

2012-04-01

Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

Enhancement of Localized Surface Plasmon Resonance polymer based biosensor chips using well-defined glycopolymers for lectin detection.

PubMed

Jin, Yan; Wong, Kok Hou; Granville, Anthony Michael

2016-01-15

Poly(methyl methacrylate) polymer based Localized Surface Plasmon Resonance biosensor chips were successfully fabricated using glycopolymer brushes carrying glucose moieties for the detection of concanavalin A. Poly(pentafluorostyrene), with pre-determined polymer chain lengths, were synthesized via a reversible addition-fragmentation chain transfer polymerization technique. The synthesized poly(pentafluorostyrene), was subsequently converted into glycopolymers via a para-fluoro-thiol "click" reaction and grafted onto the surface of sensor chips. The "glycocluster effect" induced by pendent carbohydrate moieties enabled a stronger affinity for concanavalin A binding, which resulted in a dramatic expansion of the sensors' response range. It was discovered that the longer polymer brushes did not guarantee additional enhancements for the sensor chips. Instead, they could lead to higher detection limits. In this study, the limit of detection for the sensor chips was discovered to be 1.3nmolL(-1) with a saturated response at 1054.2nmolL(-1). In addition to the superior performance, the capabilities of the reported sensor chips can be easily manipulated to detect a diverse range of analytes by "clicking" various sensing elements onto the polymer brushes. Copyright © 2015 Elsevier Inc. All rights reserved.

Multiple SNP Markers Reveal Fine-Scale Population and Deep Phylogeographic Structure in European Anchovy (Engraulis encrasicolus L.)

PubMed Central

Zarraonaindia, Iratxe; Iriondo, Mikel; Albaina, Aitor; Pardo, Miguel Angel; Manzano, Carmen; Grant, W. Stewart; Irigoien, Xabier; Estonba, Andone

2012-01-01

Geographic surveys of allozymes, microsatellites, nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) have detected several genetic subdivisions among European anchovy populations. However, these studies have been limited in their power to detect some aspects of population structure by the use of a single or a few molecular markers, or by limited geographic sampling. We use a multi-marker approach, 47 nDNA and 15 mtDNA single nucleotide polymorphisms (SNPs), to analyze 626 European anchovies from the whole range of the species to resolve shallow and deep levels of population structure. Nuclear SNPs define 10 genetic entities within two larger genetically distinctive groups associated with oceanic variables and different life-history traits. MtDNA SNPs define two deep phylogroups that reflect ancient dispersals and colonizations. These markers define two ecological groups. One major group of Iberian-Atlantic populations is associated with upwelling areas on narrow continental shelves and includes populations spawning and overwintering in coastal areas. A second major group includes northern populations in the North East (NE) Atlantic (including the Bay of Biscay) and the Mediterranean and is associated with wide continental shelves with local larval retention currents. This group tends to spawn and overwinter in oceanic areas. These two groups encompass ten populations that differ from previously defined management stocks in the Alboran Sea, Iberian-Atlantic and Bay of Biscay regions. In addition, a new North Sea-English Channel stock is defined. SNPs indicate that some populations in the Bay of Biscay are genetically closer to North Western (NW) Mediterranean populations than to other populations in the NE Atlantic, likely due to colonizations of the Bay of Biscay and NW Mediterranean by migrants from a common ancestral population. Northern NE Atlantic populations were subsequently established by migrants from the Bay of Biscay. Populations along the Iberian-Atlantic coast appear to have been founded by secondary waves of migrants from a southern refuge. PMID:22860082

Detection And Mapping (DAM) package. Volume 4B: Software System Manual, part 2

NASA Technical Reports Server (NTRS)

Schlosser, E. H.

1980-01-01

Computer programs, graphic devices, and an integrated set of manual procedures designed for efficient production of precisely registered and formatted maps from digital data are presented. The software can be used on any Univac 1100 series computer. The software includes pre-defined spectral limits for use in classifying and mapping surface water for LANDSAT-1, LANDSAT-2, and LANDSAT-3.

Natural occurrence of alternariol and alternariol monomethyl ether in soya beans.

PubMed

Oviedo, M S; Barros, G G; Chulze, S N; Ramirez, M L

2012-08-01

The natural occurrence of alternariol (AOH) and alternariol monomethyl ether (AME) in soya beans harvested in Argentina was evaluated. Both toxins were simultaneously detected by using HPLC analysis coupled with a solid phase extraction column clean-up. Characteristics of this in-house method such as accuracy, precision and detection and quantification limits were defined by means of recovery test with spiked soya bean samples. Out of 50 soya bean samples, 60% showed contamination with the mycotoxins analyzed; among them, 16% were only contaminated with AOH and 14% just with AME. Fifteen of the positive samples showed co-occurrence of both mycotoxins analyzed. AOH was detected in concentrations ranging from 25 to 211 ng/g, whereas AME was found in concentrations ranging from 62 to 1,153 ng/g. Although a limited number of samples were evaluated, this is the first report on the natural occurrence of Alternaria toxins in soya beans and is relevant from the point of view of animal public health.

Detecting Candida albicans in human milk.

PubMed

Morrill, Jimi Francis; Pappagianis, Demosthenes; Heinig, M Jane; Lönnerdal, Bo; Dewey, Kathryn G

2003-01-01

Procedures for diagnosis of mammary candidosis, including laboratory confirmation, are not well defined. Lactoferrin present in human milk can inhibit growth of Candida albicans, thereby limiting the ability to detect yeast infections. The inhibitory effect of various lactoferrin concentrations on the growth of C. albicans in whole human milk was studied. The addition of iron to the milk led to a two- to threefold increase in cell counts when milk contained 3.0 mg of lactoferrin/ml and markedly reduced the likelihood of false-negative culture results. This method may provide the necessary objective support needed for diagnosis of mammary candidosis.

Diagnostic strategy for occult hepatitis B virus infection

PubMed Central

Ocana, Sara; Casas, Maria Luisa; Buhigas, Ingrid; Lledo, Jose Luis

2011-01-01

In 2008, the European Association for the study of the liver (EASL) defined occult hepatitis B virus infection (OBI) as the “presence of hepatitis B virus (HBV) DNA in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing hepatitis B surface antigen (HBsAg) negative by currently available assays”. Several aspects of occult HBV infection are still poorly understood, including the definition itself and a standardized approach for laboratory-based detection, which is the purpose of this review. The clinical significance of OBI has not yet been established; however, in terms of public health, the clinical importance arises from the risk of HBV transmission. Consequently, it is important to detect high-risk groups for occult HBV infection to prevent transmission. The main issue is, perhaps, to identify the target population for screening OBI. Viremia is very low or undetectable in occult HBV infection, even when the most sensitive methods are used, and the detection of the viral DNA reservoir in hepatocytes would provide the best evaluation of occult HBV prevalence in a defined set of patients. However, this diagnostic approach is obviously unsuitable: blood detection of occult hepatitis B requires assays of the highest sensitivity and specificity with a lower limit of detection < 10 IU/mL for HBV DNA and < 0.1 ng/mL for HBsAg. PMID:21472120

Evaluation of Beckman Coulter DxI 800 immunoassay system using clinically oriented performance goals.

PubMed

Akbas, Neval; Schryver, Patricia G; Algeciras-Schimnich, Alicia; Baumann, Nikola A; Block, Darci R; Budd, Jeffrey R; Gaston, S J Stephen; Klee, George G

2014-11-01

We evaluated the analytical performance of 24 immunoassays using the Beckman Coulter DxI 800 immunoassay systems at Mayo Clinic, Rochester, MN for trueness, precision, detection limits, linearity, and consistency (across instruments and reagent lots). Clinically oriented performance goals were defined using the following methods: trueness-published desirable accuracy limits, precision-published desirable biologic variation; detection limits - 0.1 percentile of patient test values, linearity - 50% of total error, and consistency-percentage test values crossing key decision points. Local data were collected for precision, linearity, and consistency. Data were provided by Beckman Coulter, Inc. for trueness and detection limits. All evaluated assays except total thyroxine were within the proposed goals for trueness. Most of the assays met the proposed goals for precision (86% of intra-assay results and 75% of inter-assay results). Five assays had more than 15% of the test results below the minimum detection limits. Carcinoembryonic antigen, total thyroxine and free triiodothyronine exceeded the proposed goals of ±6.3%, ±5% and ±5.7% for dilution linearity. All evaluated assays were within the proposed goals for instrument consistency. Lot-to-lot consistency results for cortisol, ferritin and total thyroxine exceeded the proposed goals of 3.3%, 11.4% and 7% at one medical decision level, while vitamin B12 exceeded the proposed goals of 5.2% and 3.8% at two decision levels. The Beckman Coulter DxI 800 immunoassay system meets most of these proposed goals, even though these clinically focused performance goals represent relatively stringent limits. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Evaluating Measurement of Dynamic Constructs: Defining a Measurement Model of Derivatives

PubMed Central

Estabrook, Ryne

2015-01-01

While measurement evaluation has been embraced as an important step in psychological research, evaluating measurement structures with longitudinal data is fraught with limitations. This paper defines and tests a measurement model of derivatives (MMOD), which is designed to assess the measurement structure of latent constructs both for analyses of between-person differences and for the analysis of change. Simulation results indicate that MMOD outperforms existing models for multivariate analysis and provides equivalent fit to data generation models. Additional simulations show MMOD capable of detecting differences in between-person and within-person factor structures. Model features, applications and future directions are discussed. PMID:24364383

Verification of spectrophotometric method for nitrate analysis in water samples

NASA Astrophysics Data System (ADS)

Kurniawati, Puji; Gusrianti, Reny; Dwisiwi, Bledug Bernanti; Purbaningtias, Tri Esti; Wiyantoko, Bayu

2017-12-01

The aim of this research was to verify the spectrophotometric method to analyze nitrate in water samples using APHA 2012 Section 4500 NO3-B method. The verification parameters used were: linearity, method detection limit, level of quantitation, level of linearity, accuracy and precision. Linearity was obtained by using 0 to 50 mg/L nitrate standard solution and the correlation coefficient of standard calibration linear regression equation was 0.9981. The method detection limit (MDL) was defined as 0,1294 mg/L and limit of quantitation (LOQ) was 0,4117 mg/L. The result of a level of linearity (LOL) was 50 mg/L and nitrate concentration 10 to 50 mg/L was linear with a level of confidence was 99%. The accuracy was determined through recovery value was 109.1907%. The precision value was observed using % relative standard deviation (%RSD) from repeatability and its result was 1.0886%. The tested performance criteria showed that the methodology was verified under the laboratory conditions.

Far-infrared photometry of compact extragalactic objects - Detection of 3C 345

NASA Technical Reports Server (NTRS)

Harvey, P. M.; Wilking, B. A.; Joy, M.

1982-01-01

The first detection of a quasar between 10 and 1000 microns is reported. The observation permits (1) the determination of the intersection of the optical/infrared and millimeter continua; (2) more precise determination of the total luminosity; (3) the placing of limits on the contribution of any thermal dust emission to the total luminosity. The quasar is the first object ever to have been observed whose energy distribution peaks at wavelength of about 100 microns without a large contribution to the total luminosity from thermal dust emission. The observed flux density of 2.2 + or - 0.5 Jy at 100 microns and an upper limit of 0.5 + or - 0.6 Jy at 50 microns clearly define the overall energy distribution and show the quasar to be a powerful far-infrared source.

Serum Cystatin C– Versus Creatinine-Based Definitions of Acute Kidney Injury Following Cardiac Surgery: A Prospective Cohort Study

PubMed Central

Spahillari, Aferdita; Parikh, Chirag R.; Sint, Kyaw; Koyner, Jay L.; Patel, Uptal D.; Edelstein, Charles L.; Passik, Cary S.; Thiessen-Philbrook, Heather; Swaminathan, Madhav; Shlipak, Michael G.

2012-01-01

Background The primary aim of this study was to compare the sensitivity and rapidity of AKI detection by cystatin C relative to creatinine following cardiac surgery. Study Design Prospective cohort study Settings and Participants 1,150 high-risk, adult cardiac surgery patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium. Predictor Changes in serum creatinine and cystatin C Outcome Post-surgical incidence of AKI Measurements Serum creatinine and cystatin C were measured at the preoperative visit and daily on postoperative days 1–5. To allow comparisons between changes in creatinine and cystatin C, AKI endpoints were defined by the relative increases in each marker from baseline (25, 50 and 100%) and the incidence of AKI was compared based upon each marker. Secondary aims were to compare clinical outcomes among patients defined as having AKI by cystatin C and/or creatinine. Results Overall, serum creatinine detected more cases of AKI than cystatin C: 35% developed a ≥25% increase in serum creatinine, whereas only 23% had ≥25% increase in cystatin C (p < 0.001). Creatinine also had higher proportions meeting the 50% (14% and 8%, p<0.001) and 100% (4% and 2%, p=0.005) thresholds for AKI diagnosis. Clinical outcomes were generally not statistically different for AKI cases detected by creatinine or cystatin C. However, for each AKI threshold, patients with AKI confirmed by both markers had significantly higher risk of the combined mortality/dialysis outcome compared with patients with AKI detected by creatinine alone (p=0.002). Limitations There were few adverse clinical outcomes, limiting our ability to detect differences in outcomes between subgroups of patients based upon their definitions of AKI. Conclusion In this large multicenter study, we found that cystatin C was less sensitive for AKI detection compared with creatinine. However, confirmation by cystatin C appeared to identify a subset of AKI patients with substantially higher risk of adverse outcomes. PMID:22809763

Thermal noise limit for ultra-high vacuum noncontact atomic force microscopy

PubMed Central

Lübbe, Jannis; Temmen, Matthias; Rode, Sebastian; Rahe, Philipp; Kühnle, Angelika

2013-01-01

Summary The noise of the frequency-shift signal Δf in noncontact atomic force microscopy (NC-AFM) consists of cantilever thermal noise, tip–surface-interaction noise and instrumental noise from the detection and signal processing systems. We investigate how the displacement-noise spectral density d z at the input of the frequency demodulator propagates to the frequency-shift-noise spectral density d Δ f at the demodulator output in dependence of cantilever properties and settings of the signal processing electronics in the limit of a negligible tip–surface interaction and a measurement under ultrahigh-vacuum conditions. For a quantification of the noise figures, we calibrate the cantilever displacement signal and determine the transfer function of the signal-processing electronics. From the transfer function and the measured d z, we predict d Δ f for specific filter settings, a given level of detection-system noise spectral density d z ds and the cantilever-thermal-noise spectral density d z th. We find an excellent agreement between the calculated and measured values for d Δ f. Furthermore, we demonstrate that thermal noise in d Δ f, defining the ultimate limit in NC-AFM signal detection, can be kept low by a proper choice of the cantilever whereby its Q-factor should be given most attention. A system with a low-noise signal detection and a suitable cantilever, operated with appropriate filter and feedback-loop settings allows room temperature NC-AFM measurements at a low thermal-noise limit with a significant bandwidth. PMID:23400758

Thermal noise limit for ultra-high vacuum noncontact atomic force microscopy.

PubMed

Lübbe, Jannis; Temmen, Matthias; Rode, Sebastian; Rahe, Philipp; Kühnle, Angelika; Reichling, Michael

2013-01-01

The noise of the frequency-shift signal Δf in noncontact atomic force microscopy (NC-AFM) consists of cantilever thermal noise, tip-surface-interaction noise and instrumental noise from the detection and signal processing systems. We investigate how the displacement-noise spectral density d(z) at the input of the frequency demodulator propagates to the frequency-shift-noise spectral density d(Δ) (f) at the demodulator output in dependence of cantilever properties and settings of the signal processing electronics in the limit of a negligible tip-surface interaction and a measurement under ultrahigh-vacuum conditions. For a quantification of the noise figures, we calibrate the cantilever displacement signal and determine the transfer function of the signal-processing electronics. From the transfer function and the measured d(z), we predict d(Δ) (f) for specific filter settings, a given level of detection-system noise spectral density d(z) (ds) and the cantilever-thermal-noise spectral density d(z) (th). We find an excellent agreement between the calculated and measured values for d(Δ) (f). Furthermore, we demonstrate that thermal noise in d(Δ) (f), defining the ultimate limit in NC-AFM signal detection, can be kept low by a proper choice of the cantilever whereby its Q-factor should be given most attention. A system with a low-noise signal detection and a suitable cantilever, operated with appropriate filter and feedback-loop settings allows room temperature NC-AFM measurements at a low thermal-noise limit with a significant bandwidth.

Iterative Strategies for Aftershock Classification in Automatic Seismic Processing Pipelines

NASA Astrophysics Data System (ADS)

Gibbons, Steven J.; Kværna, Tormod; Harris, David B.; Dodge, Douglas A.

2016-04-01

Aftershock sequences following very large earthquakes present enormous challenges to near-realtime generation of seismic bulletins. The increase in analyst resources needed to relocate an inflated number of events is compounded by failures of phase association algorithms and a significant deterioration in the quality of underlying fully automatic event bulletins. Current processing pipelines were designed a generation ago and, due to computational limitations of the time, are usually limited to single passes over the raw data. With current processing capability, multiple passes over the data are feasible. Processing the raw data at each station currently generates parametric data streams which are then scanned by a phase association algorithm to form event hypotheses. We consider the scenario where a large earthquake has occurred and propose to define a region of likely aftershock activity in which events are detected and accurately located using a separate specially targeted semi-automatic process. This effort may focus on so-called pattern detectors, but here we demonstrate a more general grid search algorithm which may cover wider source regions without requiring waveform similarity. Given many well-located aftershocks within our source region, we may remove all associated phases from the original detection lists prior to a new iteration of the phase association algorithm. We provide a proof-of-concept example for the 2015 Gorkha sequence, Nepal, recorded on seismic arrays of the International Monitoring System. Even with very conservative conditions for defining event hypotheses within the aftershock source region, we can automatically remove over half of the original detections which could have been generated by Nepal earthquakes and reduce the likelihood of false associations and spurious event hypotheses. Further reductions in the number of detections in the parametric data streams are likely using correlation and subspace detectors and/or empirical matched field processing.

Aerial Port of Embarkation Capability Planning. Volume 1.

DTIC Science & Technology

1983-09-01

been defined or standardized by 3 Headquarters USAF. One definition of the reception pro- cess limits activites to providing food , shelter, and other...detect errors or omis- sions and direct the cargo or personnel to the appropriate processing area. Additionally, the APOE must supply food and shelter... food and shelter as required for these people (10). For some APOEs this could create excessive workloads simultaneously with maximum deployment

Clinically Practical Magnetic Resonance Protocol for Improved Specifically in Breast Cancer Diagnosis

DTIC Science & Technology

2006-06-01

MRI, MRS, DCE, Choline , Perfusion, Breast Cancer, Diagnosis, Specificity 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18...data analysis, patient recruitment and consent, and can now perform these tasks independently. 3. Through interactions with the DOD representative (Dr...out at 4 cc/sec during perfusion MRI acquisition. The detection of an apparent choline compounds (Cho) peak (S/N > 2) at 3.23 ppm was defined as

NearSense - Advances Towards a Silicon-Based Terahertz Near-Field Imaging Sensor for Ex Vivo Breast Tumour Identification

NASA Astrophysics Data System (ADS)

Mavarani, Laven; Hillger, Philipp; Bücher, Thomas; Grzyb, Janusz; Pfeiffer, Ullrich R.; Cassar, Quentin; Al-Ibadi, Amel; Zimmer, Thomas; Guillet, Jean-Paul; Mounaix, Patrick; MacGrogan, Gaëtan

2018-03-01

Breast Cancer is one of the most frequently diagnosed cancer diseases worldwide, and the most common invasive tumour for women. As with all cancers, early detection plays a major role in reducing the mortality and morbidity rate. Currently, most breast cancers are detected due to clinical symptoms, or by screening mammography. The limitations of these techniques have resulted in research of alternative methods for imaging and detecting breast cancer. Apart from this, it is essential to define precise tumour margins during breast-conserving surgeries to reduce the re-excision rate. This study presents the advances in the development of a silicon-based THz sub-wavelength imager usable in life science applications, especially for tumour margin identification.

PCR-based detection of a rare linear DNA in cell culture.

PubMed

Saveliev, Sergei V.

2002-11-11

The described method allows for detection of rare linear DNA fragments generated during genomic deletions. The predicted limit of the detection is one DNA molecule per 10(7) or more cells. The method is based on anchor PCR and involves gel separation of the linear DNA fragment and chromosomal DNA before amplification. The detailed chemical structure of the ends of the linear DNA can be defined with the use of additional PCR-based protocols. The method was applied to study the short-lived linear DNA generated during programmed genomic deletions in a ciliate. It can be useful in studies of spontaneous DNA deletions in cell culture or for tracking intracellular modifications at the ends of transfected DNA during gene therapy trials.

PCR-based detection of a rare linear DNA in cell culture

PubMed Central

2002-01-01

The described method allows for detection of rare linear DNA fragments generated during genomic deletions. The predicted limit of the detection is one DNA molecule per 107 or more cells. The method is based on anchor PCR and involves gel separation of the linear DNA fragment and chromosomal DNA before amplification. The detailed chemical structure of the ends of the linear DNA can be defined with the use of additional PCR-based protocols. The method was applied to study the short-lived linear DNA generated during programmed genomic deletions in a ciliate. It can be useful in studies of spontaneous DNA deletions in cell culture or for tracking intracellular modifications at the ends of transfected DNA during gene therapy trials. PMID:12734566

Clustering approaches to feature change detection

NASA Astrophysics Data System (ADS)

G-Michael, Tesfaye; Gunzburger, Max; Peterson, Janet

2018-05-01

The automated detection of changes occurring between multi-temporal images is of significant importance in a wide range of medical, environmental, safety, as well as many other settings. The usage of k-means clustering is explored as a means for detecting objects added to a scene. The silhouette score for the clustering is used to define the optimal number of clusters that should be used. For simple images having a limited number of colors, new objects can be detected by examining the change between the optimal number of clusters for the original and modified images. For more complex images, new objects may need to be identified by examining the relative areas covered by corresponding clusters in the original and modified images. Which method is preferable depends on the composition and range of colors present in the images. In addition to describing the clustering and change detection methodology of our proposed approach, we provide some simple illustrations of its application.

Mass-tag enhanced immuno-laser desorption/ionization mass spectrometry for sensitive detection of intact protein antigens.

PubMed

Lorey, Martina; Adler, Belinda; Yan, Hong; Soliymani, Rabah; Ekström, Simon; Yli-Kauhaluoma, Jari; Laurell, Thomas; Baumann, Marc

2015-05-19

A new read-out method for antibody arrays using laser desorption/ionization-mass spectrometry (LDI-MS) is presented. Small, photocleavable reporter molecules with a defined mass called "mass-tags" are used for detection of immunocaptured proteins from human plasma. Using prostate specific antigen (PSA), a biomarker for prostate cancer, as a model antigen, a high sensitivity generic detection methodology based immunocapture with a primary antibody and with a biotin labeled secondary antibody coupled to mass-tagged avidin is demonstrated. As each secondary antibody can bind several avidin molecules, each having a large number of mass-tags, signal amplification can be achieved. The developed PSA sandwich mass-tag analysis method provided a limit of detection below 200 pg/mL (6 pM) for a 10 μL plasma sample, well below the clinically relevant cutoff value of 3-4 ng/mL. This brings the limit of detection (LOD) for detection of intact antigens with matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) down to levels comparable to capture by anti-peptide antibodies selected reaction monitoring (SISCAPA SRM) and enzyme linked immunosorbent assay (ELISA), as 6 pM corresponds to a maximal amount of 60 amol PSA captured on-spot. We propose the potential use of LDI (laser desorption/ionization) with mass-tag read-out implemented in a sandwich assay format for low abundant and/or early disease biomarker detection.

A group filter algorithm for sea mine detection

NASA Astrophysics Data System (ADS)

Cobb, J. Tory; An, Myoung; Tolimieri, Richard

2005-06-01

Automatic detection of sea mines in coastal regions is a difficult task due to the highly variable sea bottom conditions present in the underwater environment. Detection systems must be able to discriminate objects which vary in size, shape, and orientation from naturally occurring and man-made clutter. Additionally, these automated systems must be computationally efficient to be incorporated into unmanned underwater vehicle (UUV) sensor systems characterized by high sensor data rates and limited processing abilities. Using noncommutative group harmonic analysis, a fast, robust sea mine detection system is created. A family of unitary image transforms associated to noncommutative groups is generated and applied to side scan sonar image files supplied by Naval Surface Warfare Center Panama City (NSWC PC). These transforms project key image features, geometrically defined structures with orientations, and localized spectral information into distinct orthogonal components or feature subspaces of the image. The performance of the detection system is compared against the performance of an independent detection system in terms of probability of detection (Pd) and probability of false alarm (Pfa).

Impact of adherence on duration of virological suppression among patients receiving combination antiretroviral therapy.

PubMed

Raboud, J M; Harris, M; Rae, S; Montaner, J S G

2002-04-01

To assess the effect of adherence to antiretroviral therapy on the duration of virological suppression after controlling for whether or not the patient ever attained a plasma viral load below the limit of detection of sensitive HIV-1 RNA assays. Data were combined from three randomized, blinded clinical trials (INCAS, AVANTI-2, and AVANTI-3) that compared the antiviral effects of two- and three-drug antiretroviral regimens. Virological suppression was defined as maintaining a plasma viral load below 1000 copies/mL. Adherence was defined prospectively and measured by patient self-report. Adherence did not have a major impact on the probability of achieving virological suppression for patients receiving dual therapy. However, for patients receiving triple therapy, adherence increased the probability of virological suppression, whether the plasma viral load nadir was above or below the lower limit of quantification. Compared to adherent patients with a plasma viral load nadir below the lower limit of quantification, the relative risk of virological failure was 3.0 for non-adherent patients with a nadir below the limit, 18.1 for adherent patients with a nadir above the limit, and 32.1 for non-adherent patients with a nadir above the limit. For patients receiving current three-drug antiretroviral regimens, adherence to therapy and plasma viral load nadir are important factors determining the duration of virological suppression.

Automatic learning of rules. A practical example of using artificial intelligence to improve computer-based detection of myocardial infarction and left ventricular hypertrophy in the 12-lead ECG.

PubMed

Kaiser, W; Faber, T S; Findeis, M

1996-01-01

The authors developed a computer program that detects myocardial infarction (MI) and left ventricular hypertrophy (LVH) in two steps: (1) by extracting parameter values from a 10-second, 12-lead electrocardiogram, and (2) by classifying the extracted parameter values with rule sets. Every disease has its dedicated set of rules. Hence, there are separate rule sets for anterior MI, inferior MI, and LVH. If at least one rule is satisfied, the disease is said to be detected. The computer program automatically develops these rule sets. A database (learning set) of healthy subjects and patients with MI, LVH, and mixed MI+LVH was used. After defining the rule type, initial limits, and expected quality of the rules (positive predictive value, minimum number of patients), the program creates a set of rules by varying the limits. The general rule type is defined as: disease = lim1l < p1 < or = lim1u and lim2l < p2 < or = lim2u and ... limnl < pn < or = limnu. When defining the rule types, only the parameters (p1 ... pn) that are known as clinical electrocardiographic criteria (amplitudes [mV] of Q, R, and T waves and ST-segment; duration [ms] of Q wave; frontal angle [degrees]) were used. This allowed for submitting the learned rule sets to an independent investigator for medical verification. It also allowed the creation of explanatory texts with the rules. These advantages are not offered by the neurons of a neural network. The learned rules were checked against a test set and the following results were obtained: MI: sensitivity 76.2%, positive predictive value 98.6%; LVH: sensitivity 72.3%, positive predictive value 90.9%. The specificity ratings for MI are better than 98%; for LVH, better than 90%.

Molecular methods for pathogen and microbial community detection and characterization: current and potential application in diagnostic microbiology.

PubMed

Sibley, Christopher D; Peirano, Gisele; Church, Deirdre L

2012-04-01

Clinical microbiology laboratories worldwide have historically relied on phenotypic methods (i.e., culture and biochemical tests) for detection, identification and characterization of virulence traits (e.g., antibiotic resistance genes, toxins) of human pathogens. However, limitations to implementation of molecular methods for human infectious diseases testing are being rapidly overcome allowing for the clinical evaluation and implementation of diverse technologies with expanding diagnostic capabilities. The advantages and limitation of molecular techniques including real-time polymerase chain reaction, partial or whole genome sequencing, molecular typing, microarrays, broad-range PCR and multiplexing will be discussed. Finally, terminal restriction fragment length polymorphism (T-RFLP) and deep sequencing are introduced as technologies at the clinical interface with the potential to dramatically enhance our ability to diagnose infectious diseases and better define the epidemiology and microbial ecology of a wide range of complex infections. Copyright © 2012 Elsevier B.V. All rights reserved.

Computational Reduction of Specimen Noise to Enable Improved Thermography Characterization of Flaws in Graphite Polymer Composites

NASA Technical Reports Server (NTRS)

Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

2014-01-01

Flaw detection and characterization with thermographic techniques in graphite polymer composites are often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These result in a "noise" floor that increases the difficulty of detecting and characterizing deeper flaws. A method is presented for computationally removing a significant amount of the "noise" from near surface porosity by diffusing the early time response, then subtracting it from subsequent responses. Simulations of the thermal response of a composite are utilized in defining the limitations of the technique. This method for reducing the data is shown to give considerable improvement characterizing both the size and depth of damage. Examples are shown for data acquired on specimens with fabricated delaminations and impact damage.

DQE analysis for CCD imaging arrays

NASA Astrophysics Data System (ADS)

Shaw, Rodney

1997-05-01

By consideration of the statistical interaction between exposure quanta and the mechanisms of image detection, the signal-to-noise limitations of a variety of image acquisition technologies are now well understood. However in spite of the growing fields of application for CCD imaging- arrays and the obvious advantages of their multi-level mode of quantum detection, only limited and largely empirical approaches have been made to quantify these advantages on an absolute basis. Here an extension is made of a previous model for noise-free sequential photon-counting to the more general case involving both count-noise and arbitrary separation functions between count levels. This allows a basic model to be developed for the DQE associated with devices which approximate to the CCD mode of operation, and conclusions to be made concerning the roles of the separation-function and count-noise in defining the departure from the ideal photon counter.

Signal Detection Theory Applied to Helicopter Transmission Diagnostic Thresholds

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Keller, Jonathan A.; Wade, Daniel R.

2008-01-01

Helicopter Health Usage Monitoring Systems (HUMS) have potential for providing data to support increasing the service life of a dynamic mechanical component in the transmission of a helicopter. Data collected can demonstrate the HUMS condition indicator responds to a specific component fault with appropriate alert limits and minimal false alarms. Defining thresholds for specific faults requires a tradeoff between the sensitivity of the condition indicator (CI) limit to indicate damage and the number of false alarms. A method using Receiver Operating Characteristic (ROC) curves to assess CI performance was demonstrated using CI data collected from accelerometers installed on several UH60 Black Hawk and AH64 Apache helicopters and an AH64 helicopter component test stand. Results of the analysis indicate ROC curves can be used to reliably assess the performance of commercial HUMS condition indicators to detect damaged gears and bearings in a helicopter transmission.

Computational reduction of specimen noise to enable improved thermography characterization of flaws in graphite polymer composites

NASA Astrophysics Data System (ADS)

Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

2014-05-01

Flaw detection and characterization with thermographic techniques in graphite polymer composites are often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These result in a "noise" floor that increases the difficulty of detecting and characterizing deeper flaws. A method is presented for computationally removing a significant amount of the "noise" from near surface porosity by diffusing the early time response, then subtracting it from subsequent responses. Simulations of the thermal response of a composite are utilized in defining the limitations of the technique. This method for reducing the data is shown to give considerable improvement characterizing both the size and depth of damage. Examples are shown for data acquired on specimens with fabricated delaminations and impact damage.

Tuning fork enhanced interferometric photoacoustic spectroscopy: a new method for trace gas analysis

NASA Astrophysics Data System (ADS)

Köhring, M.; Pohlkötter, A.; Willer, U.; Angelmahr, M.; Schade, W.

2011-01-01

A photoacoustic trace gas sensor based on an optical read-out method of a quartz tuning fork is shown. Instead of conventional piezoelectric signal read-out, as applied in well-known quartz-enhanced photoacoustic spectroscopy (QEPAS), an interferometric read-out method for measurement of the tuning fork's oscillation is presented. To demonstrate the potential of the optical read-out of tuning forks in photoacoustics, a comparison between the performances of a sensor with interferometric read-out and conventional QEPAS with piezoelectric read-out is reported. The two sensors show similar characteristics. The detection limit (L) for the optical read-out is determined to be L opt=(2598±84) ppm (1 σ) compared to L elec=(2579±78) ppm (1 σ) for piezoelectric read-out. In both cases the detection limit is defined by the thermal noise of the tuning fork.

Signal Detection Theory Applied to Helicopter Transmission Diagnostic Thresholds

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Keller, Jonathan A.; Wade, Daniel R.

2009-01-01

Helicopter Health Usage Monitoring Systems (HUMS) have potential for providing data to support increasing the service life of a dynamic mechanical component in the transmission of a helicopter. Data collected can demonstrate the HUMS condition indicator responds to a specific component fault with appropriate alert limits and minimal false alarms. Defining thresholds for specific faults requires a tradeoff between the sensitivity of the condition indicator (CI) limit to indicate damage and the number of false alarms. A method using Receiver Operating Characteristic (ROC) curves to assess CI performance was demonstrated using CI data collected from accelerometers installed on several UH60 Black Hawk and AH64 Apache helicopters and an AH64 helicopter component test stand. Results of the analysis indicate ROC curves can be used to reliably assess the performance of commercial HUMS condition indicators to detect damaged gears and bearings in a helicopter transmission.

Estimate of within population incremental selection through branch imbalance in lineage trees

PubMed Central

Liberman, Gilad; Benichou, Jennifer I.C.; Maman, Yaakov; Glanville, Jacob; Alter, Idan; Louzoun, Yoram

2016-01-01

Incremental selection within a population, defined as limited fitness changes following mutation, is an important aspect of many evolutionary processes. Strongly advantageous or deleterious mutations are detected using the synonymous to non-synonymous mutations ratio. However, there are currently no precise methods to estimate incremental selection. We here provide for the first time such a detailed method and show its precision in multiple cases of micro-evolution. The proposed method is a novel mixed lineage tree/sequence based method to detect within population selection as defined by the effect of mutations on the average number of offspring. Specifically, we propose to measure the log of the ratio between the number of leaves in lineage trees branches following synonymous and non-synonymous mutations. The method requires a high enough number of sequences, and a large enough number of independent mutations. It assumes that all mutations are independent events. It does not require of a baseline model and is practically not affected by sampling biases. We show the method's wide applicability by testing it on multiple cases of micro-evolution. We show that it can detect genes and inter-genic regions using the selection rate and detect selection pressures in viral proteins and in the immune response to pathogens. PMID:26586802

Indoor determinants of dustborne allergens in Mexican homes

PubMed Central

Hernández-Cadena, Leticia; Zeldin, Darryl C.; Sever, Michelle L.; Sly, Peter D.; London, Stephanie J.; Escamilla-Nuñez, María Consuelo; Romieu, Isabelle

2015-01-01

Exposure to indoor allergens represents a significant risk factor for allergies and asthma in several parts of the world. In Mexico, few studies have evaluated indoor allergens, including cat, dog, and mouse allergens and the factors that predict their presence. This study evaluates the main environmental and household predictors of high prenatal allergen levels and multiple allergen exposures in a birth cohort from Mexico City. A cross-sectional study was conducted as part of a birth cohort study of 1094 infants recruited during pregnancy and followed until delivery. We collected dust samples in a subset of 264 homes and assessed environmental factors. Der p 1, Der f 1, dust mite group 2, Fel d 1, Can f 1, Rat n 1, Mus m 1, and Bla g 2 concentrations in dust samples were measured using immunoassays. To define detectable allergen levels, the lowest limits of detection for each allergen were taken as cutoff points. Overall allergen exposure was considered high when four or more allergens exceeded detectable levels in the same household. Logistic regression was used for predictive models. Eighty-five percent of homes had at least one allergen in dust over the detection limit, 52.1% had high exposure (four or more allergens above detectable limits), and 11.7% of homes had detectable levels for more than eight allergens. Der p 1, Der p 2, Mus m 1, and Fel d 1 were the most frequent allergens detected. Each allergen had both common and distinct predictors. The main predictors of a high multiple allergen index were the size of the home, pesticide use, mother's age, mother as homemaker, and season. Increased indoor environmental allergen exposure is mainly related to sociodemographic factors and household cleaning. PMID:25715241

Evaluation of a Broad-Spectrum Partially Automated Adverse Event Surveillance System: A Potential Tool for Patient Safety Improvement in Hospitals With Limited Resources.

PubMed

Saikali, Melody; Tanios, Alain; Saab, Antoine

2017-11-21

The aim of the study was to evaluate the sensitivity and resource efficiency of a partially automated adverse event (AE) surveillance system for routine patient safety efforts in hospitals with limited resources. Twenty-eight automated triggers from the hospital information system's clinical and administrative databases identified cases that were then filtered by exclusion criteria per trigger and then reviewed by an interdisciplinary team. The system, developed and implemented using in-house resources, was applied for 45 days of surveillance, for all hospital inpatient admissions (N = 1107). Each trigger was evaluated for its positive predictive value (PPV). Furthermore, the sensitivity of the surveillance system (overall and by AE category) was estimated relative to incidence ranges in the literature. The surveillance system identified a total of 123 AEs among 283 reviewed medical records, yielding an overall PPV of 52%. The tool showed variable levels of sensitivity across and within AE categories when compared with the literature, with a relatively low overall sensitivity estimated between 21% and 44%. Adverse events were detected in 23 of the 36 AE categories defined by an established harm classification system. Furthermore, none of the detected AEs were voluntarily reported. The surveillance system showed variable sensitivity levels across a broad range of AE categories with an acceptable PPV, overcoming certain limitations associated with other harm detection methods. The number of cases captured was substantial, and none had been previously detected or voluntarily reported. For hospitals with limited resources, this methodology provides valuable safety information from which interventions for quality improvement can be formulated.

Using Hashimoto thyroiditis as gold standard to determine the upper limit value of thyroid stimulating hormone in a Chinese cohort.

PubMed

Li, Yu; Chen, Dong-Ning; Cui, Jing; Xin, Zhong; Yang, Guang-Ran; Niu, Ming-Jia; Yang, Jin-Kui

2016-11-06

Subclinical hypothyroidism, commonly caused by Hashimoto thyroiditis (HT), is a risk factor for cardiovascular diseases. This disorder is defined as merely having elevated serum thyroid stimulating hormone (TSH) levels. However, the upper limit of reference range for TSH is debated recently. This study was to determine the cutoff value for the upper normal limit of TSH in a cohort using the prevalence of Hashimoto thyroiditis as "gold" calibration standard. The research population was medical staff of 2856 individuals who took part in health examination annually. Serum free triiodothyronine (FT3), free thyroxine (FT4), TSH, thyroid peroxidase antibody (TPAb), thyroglobulin antibody (TGAb) and other biochemistry parameters were tested. Meanwhile, thyroid ultrasound examination was performed. The diagnosis of HT was based on presence of thyroid antibodies (TPAb and TGAb) and abnormalities of thyroid ultrasound examination. We used two different methods to estimate the cutoff point of TSH based on the prevalence of HT. Joinpoint regression showed the prevalence of HT increased significantly at the ninth decile of TSH value corresponding to 2.9 mU/L. ROC curve showed a TSH cutoff value of 2.6 mU/L with the maximized sensitivity and specificity in identifying HT. Using the newly defined cutoff value of TSH can detect patients with hyperlipidemia more efficiently, which may indicate our approach to define the upper limit of TSH can make more sense from the clinical point of view. A significant increase in the prevalence of HT occurred among individuals with a TSH of 2.6-2.9 mU/L made it possible to determine the cutoff value of normal upper limit of TSH.

A non-earthcentric approach to life detection

NASA Technical Reports Server (NTRS)

Conrad, P. G.; Nealson, K. H.

2001-01-01

The ultimate goal of a comprehensive life detection strategy is never to miss life when we encounter it. To accomplish this goal, we must define life in universal, that is, non-Earthcentric, measurable terms. Next, we must understand the nature of biosignatures observed from the measured parameters of life. And finally, we must have a clear idea of the end-member states for the search--what does life, past life, or no life look like (in terms of the measured parameters) at multiple spatial and temporal scales? If we can approach these problems both in the laboratory and in the field on Earth, then we have a chance of being able to detect life elsewhere in our solar system. What are the required limits of detection at each of those scales? What spatial, spectral, and temporal resolutions are necessary to detect life? These questions are actively being investigated in our group, and in this report, we present our strategy and approach to non-Earthcentric life detection.

Supervised target detection in hyperspectral images using one-class Fukunaga-Koontz Transform

NASA Astrophysics Data System (ADS)

Binol, Hamidullah; Bal, Abdullah

2016-05-01

A novel hyperspectral target detection technique based on Fukunaga-Koontz transform (FKT) is presented. FKT offers significant properties for feature selection and ordering. However, it can only be used to solve multi-pattern classification problems. Target detection may be considered as a two-class classification problem, i.e., target versus background clutter. Nevertheless, background clutter typically contains different types of materials. That's why; target detection techniques are different than classification methods by way of modeling clutter. To avoid the modeling of the background clutter, we have improved one-class FKT (OC-FKT) for target detection. The statistical properties of target training samples are used to define tunnel-like boundary of the target class. Non-target samples are then created synthetically as to be outside of the boundary. Thus, only limited target samples become adequate for training of FKT. The hyperspectral image experiments confirm that the proposed OC-FKT technique provides an effective means for target detection.

Quantifying environmental limiting factors on tree cover using geospatial data.

PubMed

Greenberg, Jonathan A; Santos, Maria J; Dobrowski, Solomon Z; Vanderbilt, Vern C; Ustin, Susan L

2015-01-01

Environmental limiting factors (ELFs) are the thresholds that determine the maximum or minimum biological response for a given suite of environmental conditions. We asked the following questions: 1) Can we detect ELFs on percent tree cover across the eastern slopes of the Lake Tahoe Basin, NV? 2) How are the ELFs distributed spatially? 3) To what extent are unmeasured environmental factors limiting tree cover? ELFs are difficult to quantify as they require significant sample sizes. We addressed this by using geospatial data over a relatively large spatial extent, where the wall-to-wall sampling ensures the inclusion of rare data points which define the minimum or maximum response to environmental factors. We tested mean temperature, minimum temperature, potential evapotranspiration (PET) and PET minus precipitation (PET-P) as potential limiting factors on percent tree cover. We found that the study area showed system-wide limitations on tree cover, and each of the factors showed evidence of being limiting on tree cover. However, only 1.2% of the total area appeared to be limited by the four (4) environmental factors, suggesting other unmeasured factors are limiting much of the tree cover in the study area. Where sites were near their theoretical maximum, non-forest sites (tree cover < 25%) were primarily limited by cold mean temperatures, open-canopy forest sites (tree cover between 25% and 60%) were primarily limited by evaporative demand, and closed-canopy forests were not limited by any particular environmental factor. The detection of ELFs is necessary in order to fully understand the width of limitations that species experience within their geographic range.

Significance and Clinical Management of Persistent Low-Level Viremia and Very-Low-Level Viremia in HIV-1-Infected Patients

PubMed Central

Kelly, Sean; Li, Jonathan Z.; Harrigan, P. Richard; Taiwo, Babafemi

2014-01-01

A goal of HIV therapy is to sustain suppression of the plasma viral load below the detection limits of clinical assays. However, widely followed treatment guidelines diverge in their interpretation and recommended management of persistent viremia of low magnitude, reflecting the limited evidence base for this common clinical finding. Here, we review the incidence, risk factors, and potential consequences of low-level HIV viremia (LLV; defined in this review as a viremia level of 50 to 500 copies/ml) and very-low-level viremia (VLLV; defined as a viremia level of <50 copies/ml detected by clinical assays that have quantification cutoffs of <50 copies/ml). Using this framework, we discuss practical issues related to the diagnosis and management of patients experiencing persistent LLV and VLLV. Compared to viral suppression at <50 or 40 copies/ml, persistent LLV is associated with increased risk of antiretroviral drug resistance and overt virologic failure. Higher immune activation and HIV transmission may be additional undesirable consequences in this population. It is uncertain whether LLV of <200 copies/ml confers independent risks, as this level of viremia may reflect assay-dependent artifacts or biologically meaningful events during suppression. Resistance genotyping should be considered in patients with persistent LLV when feasible, and treatment should be modified if resistance is detected. There is a dearth of clinical evidence to guide management when genotyping is not feasible. Increased availability of genotypic assays for samples with viral loads of <400 copies/ml is needed. PMID:24733471

Orbital Signature Analyzer (OSA): A spacecraft health/safety monitoring and analysis tool

NASA Technical Reports Server (NTRS)

Weaver, Steven; Degeorges, Charles; Bush, Joy; Shendock, Robert; Mandl, Daniel

1993-01-01

Fixed or static limit sensing is employed in control centers to ensure that spacecraft parameters remain within a nominal range. However, many critical parameters, such as power system telemetry, are time-varying and, as such, their 'nominal' range is necessarily time-varying as well. Predicted data, manual limits checking, and widened limit-checking ranges are often employed in an attempt to monitor these parameters without generating excessive limits violations. Generating predicted data and manual limits checking are both resource intensive, while broadening limit ranges for time-varying parameters is clearly inadequate to detect all but catastrophic problems. OSA provides a low-cost solution by using analytically selected data as a reference upon which to base its limits. These limits are always defined relative to the time-varying reference data, rather than as fixed upper and lower limits. In effect, OSA provides individual limits tailored to each value throughout all the data. A side benefit of using relative limits is that they automatically adjust to new reference data. In addition, OSA provides a wealth of analytical by-products in its execution.

[Detection of the largest population susceptible to prescription of a program of exercises in Primary Care to prevent frailty].

PubMed

Rosas Hernández, Ana María; Alejandre Carmona, Sergio; Rodríguez Sánchez, Javier Enrique; Castell Alcalá, Maria Victoria; Otero Puime, Ángel

2018-03-16

Identify the population over 70 year's old treated in primary care who should participate in a physical exercise program to prevent frailty. Analyze the concordance among 2criteria to select the beneficiary population of the program. Population-based cross-sectional study. Primary Care. Elderly over 70 years old, living in the Peñagrande neighborhood (Fuencarral district of Madrid) from the Peñagrande cohort, who accepted to participate in 2015 (n = 332). The main variable of the study is the need for exercise prescription in people over 70 years old at the Primary Care setting. It was identified through 2different definitions: Prefrail (1-2 of 5 Fried criteria) and Independent individuals with physical performance limited, defined by Consensus on frailty and falls prevention among the elderly (independent and with a total SPPB score <10). The 63,8% of participants (n = 196) need exercise prescription based on criteria defined by Fried and/or the consensus for prevention of frailty and falls in the elderly. In 82 cases the 2criteria were met, 80 were prefrail with normal physical performance and 34 were robust with a limited physical performance. The concordance among both criteria is weak (kappa index 0, 27). Almost 2thirds of the elderly have some kind of functional limitation. The criteria of the consensus document to prevent frailty detect half of the pre-frail individuals in the community. Copyright © 2018 The Authors. Publicado por Elsevier España, S.L.U. All rights reserved.

Detection of influenza A virus using carbon nanotubes field effect transistor based DNA sensor

NASA Astrophysics Data System (ADS)

Tran, Thi Luyen; Nguyen, Thi Thuy; Huyen Tran, Thi Thu; Chu, Van Tuan; Thinh Tran, Quang; Tuan Mai, Anh

2017-09-01

The carbon nanotubes field effect transistor (CNTFET) based DNA sensor was developed, in this paper, for detection of influenza A virus DNA. Number of factors that influence the output signal and analytical results were investigated. The initial probe DNA, decides the available DNA strands on CNTs, was 10 μM. The hybridization time for defined single helix was 120 min. The hybridization temperature was set at 30 °C to get a net change in drain current of the DNA sensor without altering properties of any biological compounds. The response time of the DNA sensor was less than one minute with a high reproducibility. In addition, the DNA sensor has a wide linear detection range from 1 pM to 10 nM, and a very low detection limit of 1 pM. Finally, after 7-month storage in 7.4 pH buffer, the output signal of DNA sensor recovered 97%.

Intracardiac Shunting and Stroke in Children: A Systematic Review

PubMed Central

Dowling, Michael M.; Ikemba, Catherine M.

2017-01-01

In adults, patent foramen ovale or other potential intracardiac shunts are established risk factors for stroke via paradoxical embolization. Stroke is less common in children and risk factors differ. The authors examined the literature on intracardiac shunting and stroke in children, identifying the methods employed, the prevalence of detectible intracardiac shunts, associated conditions, and treatments. PubMed searches with keywords related to intracardiac shunting and stroke in children identified articles of interest. Additional articles were identified via citations in these articles or in reviews. The authors found that studies of intracardiac shunting in children with stroke are limited. No controlled studies were identified. Detection methods vary and the prevalence of echocardiographically detectible intracardiac shunting appears lower than reported in adults and autopsy studies. Defining the role of intracardiac shunting in pediatric stroke will require controlled studies with unified detection methods in populations stratified by additional risk factors for paradoxical embolization. Optimal treatment is unclear. PMID:21212453

Detectability of auditory signals presented without defined observation intervals

NASA Technical Reports Server (NTRS)

Watson, C. S.; Nichols, T. L.

1976-01-01

Ability to detect tones in noise was measured without defined observation intervals. Latency density functions were estimated for the first response following a signal and, separately, for the first response following randomly distributed instances of background noise. Detection performance was measured by the maximum separation between the cumulative latency density functions for signal-plus-noise and for noise alone. Values of the index of detectability, estimated by this procedure, were approximately those obtained with a 2-dB weaker signal and defined observation intervals. Simulation of defined- and non-defined-interval tasks with an energy detector showed that this device performs very similarly to the human listener in both cases.

2D Fast Vessel Visualization Using a Vessel Wall Mask Guiding Fine Vessel Detection

PubMed Central

Raptis, Sotirios; Koutsouris, Dimitris

2010-01-01

The paper addresses the fine retinal-vessel's detection issue that is faced in diagnostic applications and aims at assisting in better recognizing fine vessel anomalies in 2D. Our innovation relies in separating key visual features vessels exhibit in order to make the diagnosis of eventual retinopathologies easier to detect. This allows focusing on vessel segments which present fine changes detectable at different sampling scales. We advocate that these changes can be addressed as subsequent stages of the same vessel detection procedure. We first carry out an initial estimate of the basic vessel-wall's network, define the main wall-body, and then try to approach the ridges and branches of the vasculature's using fine detection. Fine vessel screening looks into local structural inconsistencies in vessels properties, into noise, or into not expected intensity variations observed inside pre-known vessel-body areas. The vessels are first modelled sufficiently but not precisely by their walls with a tubular model-structure that is the result of an initial segmentation. This provides a chart of likely Vessel Wall Pixels (VWPs) yielding a form of a likelihood vessel map mainly based on gradient filter's intensity and spatial arrangement parameters (e.g., linear consistency). Specific vessel parameters (centerline, width, location, fall-away rate, main orientation) are post-computed by convolving the image with a set of pre-tuned spatial filters called Matched Filters (MFs). These are easily computed as Gaussian-like 2D forms that use a limited range sub-optimal parameters adjusted to the dominant vessel characteristics obtained by Spatial Grey Level Difference statistics limiting the range of search into vessel widths of 16, 32, and 64 pixels. Sparse pixels are effectively eliminated by applying a limited range Hough Transform (HT) or region growing. Major benefits are limiting the range of parameters, reducing the search-space for post-convolution to only masked regions, representing almost 2% of the 2D volume, good speed versus accuracy/time trade-off. Results show the potentials of our approach in terms of time for detection ROC analysis and accuracy of vessel pixel (VP) detection. PMID:20706682

An observational program to search for radio signals from extraterrestrial intelligence through the use of existing facilities

NASA Technical Reports Server (NTRS)

Edelson, R. E.

1976-01-01

It is argued that a substantial portion of the capability for detecting microwave signals from extraterrestrial civilizations lies not in the application of ever larger antenna collecting areas but rather in the application of millions or billions of simultaneous frequency-channel observations combined with rapid and powerful data processing techniques. The application of these methods to existing facilities is discussed in terms of a program of modest expense and duration which will seek to discover certain classes of extraterrestrial signals of intelligent origin while defining boundaries to the search problem throughout the range of interest. This program will investigate radio-astronomical phenomena of interest and simultaneously define the background of environmental radiation in order to determine physical limitations on both the search strategies and the potential for deep-space communications. Signal parameters that must be determined are examined along with the potential of existing radio-astronomical facilities for detecting narrow-band signals. A seven-year program is described which will carry out a search for extraterrestrial intelligence over 80% of the sky and over the entire frequency range from 1 to 25 GHz with a sensitivity limit varying from 10 to the -21st power W/sq cm at the lowest frequencies to 10 to the -19th power W/sq cm at the higher frequencies.

Reproducible surface-enhanced Raman quantification of biomarkers in multicomponent mixtures.

PubMed

De Luca, Anna Chiara; Reader-Harris, Peter; Mazilu, Michael; Mariggiò, Stefania; Corda, Daniela; Di Falco, Andrea

2014-03-25

Direct and quantitative detection of unlabeled glycerophosphoinositol (GroPIns), an abundant cytosolic phosphoinositide derivative, would allow rapid evaluation of several malignant cell transformations. Here we report label-free analysis of GroPIns via surface-enhanced Raman spectroscopy (SERS) with a sensitivity of 200 nM, well below its apparent concentration in cells. Crucially, our SERS substrates, based on lithographically defined gold nanofeatures, can be used to predict accurately the GroPIns concentration even in multicomponent mixtures, avoiding the preliminary separation of individual compounds. Our results represent a critical step toward the creation of SERS-based biosensor for rapid, label-free, and reproducible detection of specific molecules, overcoming limits of current experimental methods.

Electro-optical system for gunshot detection: analysis, concept, and performance

NASA Astrophysics Data System (ADS)

Kastek, M.; Dulski, R.; Madura, H.; Trzaskawka, P.; Bieszczad, G.; Sosnowski, T.

2011-08-01

The paper discusses technical possibilities to build an effective electro-optical sensor unit for sniper detection using infrared cameras. This unit, comprising of thermal and daylight cameras, can operate as a standalone device but its primary application is a multi-sensor sniper and shot detection system. At first, the analysis was presented of three distinguished phases of sniper activity: before, during and after the shot. On the basis of experimental data the parameters defining the relevant sniper signatures were determined which are essential in assessing the capability of infrared camera to detect sniper activity. A sniper body and muzzle flash were analyzed as targets and the descriptions of phenomena which make it possible to detect sniper activities in infrared spectra as well as analysis of physical limitations were performed. The analyzed infrared systems were simulated using NVTherm software. The calculations for several cameras, equipped with different lenses and detector types were performed. The simulation of detection ranges was performed for the selected scenarios of sniper detection tasks. After the analysis of simulation results, the technical specifications of infrared sniper detection system were discussed, required to provide assumed detection range. Finally the infrared camera setup was proposed which can detected sniper from 1000 meters range.

BIOMARKERS OF OPERATIONAL TOLERANCE IN SOLID ORGAN TRANSPLANTATION

PubMed Central

Heidt, Sebastiaan; Wood, Kathryn J.

2012-01-01

Introduction Long-term immunosuppressive therapy represents a huge burden on transplant recipients, but currently cannot be omitted. Improving long-term transplant outcome by immunosuppressive drug withdrawal may be achieved in patients who have developed (partial) immunological unresponsiveness towards their graft, either spontaneously or through tolerance induction. Reliable biomarkers are essential to define such immunological unresponsiveness and will facilitate controlled immunosuppressive drug weaning as well as provide surrogate end-points for tolerance induction trials. Areas covered Tolerance biomarkers have been defined for both liver and kidney transplantation and can accurately identify operationally tolerant transplant recipients retrospectively. These two tolerance fingerprints are remarkably different, indicating the involvement of distinct mechanisms. Limited data suggest that tolerance biomarkers can be detected in immunosuppressed transplant recipients. Whether these patients can safely have their immunosuppressive drugs withdrawn needs to be established. Expert opinion Mechanistic interpretation of the kidney transplant tolerance biomarker profile dominated by B cell markers remains a challenge in light of experimental evidence suggesting the pivotal involvement of regulatory T cells. Therefore, defining animal models that resemble human transplant tolerance is crucial in understanding the underlying mechanisms. Additionally, to ensure patient safety while monitoring for tolerance, it is essential to develop biomarkers to non-invasively detect early signs of rejection as well. PMID:22988481

Fermi/LAT Observations of Swift/BAT Seyfert Galaxies: On the Contribution of Radio-Quiet Active Galactic Nuclei to the Extragalactic gamma-Ray Background

NASA Technical Reports Server (NTRS)

Teng, Stacy H.; Mushotzky, Richard F.; Sambruna, Rita M.; Davis, David S.; Reynolds, Christopher S.

2011-01-01

We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R(sub X,BAT) where radio-loud objects have logR(sub X,BAT) > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be approx.2x10(exp -11) photons/sq cm/s, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the gamma-ray (1-100 GeV) luminosity of < approx.3x10(exp 41) erg/s. In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

A Survey of Naturally-Occurring Steroid Hormones in Raw Milk and the Associated Health Risks in Tangshan City, Hebei Province, China

PubMed Central

Qu, Xueyin; Su, Chuanyou; Zheng, Nan; Li, Songli; Meng, Lu; Wang, Jiaqi

2017-01-01

In recent years, high levels of hormone residue in food, capable of damaging the health of consumers, have been recorded frequently. In this study, 195 raw milk samples were obtained from Tangshan City, China, and the concentrations of 22 steroid hormones were measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Cortisol was detected in 12.5% of raw milk samples (mean 0.61 µg/kg; range:

Data-driven fault detection, isolation and estimation of aircraft gas turbine engine actuator and sensors

NASA Astrophysics Data System (ADS)

Naderi, E.; Khorasani, K.

2018-02-01

In this work, a data-driven fault detection, isolation, and estimation (FDI&E) methodology is proposed and developed specifically for monitoring the aircraft gas turbine engine actuator and sensors. The proposed FDI&E filters are directly constructed by using only the available system I/O data at each operating point of the engine. The healthy gas turbine engine is stimulated by a sinusoidal input containing a limited number of frequencies. First, the associated system Markov parameters are estimated by using the FFT of the input and output signals to obtain the frequency response of the gas turbine engine. These data are then used for direct design and realization of the fault detection, isolation and estimation filters. Our proposed scheme therefore does not require any a priori knowledge of the system linear model or its number of poles and zeros at each operating point. We have investigated the effects of the size of the frequency response data on the performance of our proposed schemes. We have shown through comprehensive case studies simulations that desirable fault detection, isolation and estimation performance metrics defined in terms of the confusion matrix criterion can be achieved by having access to only the frequency response of the system at only a limited number of frequencies.

Iterative Strategies for Aftershock Classification in Automatic Seismic Processing Pipelines

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

Gibbons, Steven J.; Kvaerna, Tormod; Harris, David B.

We report aftershock sequences following very large earthquakes present enormous challenges to near-real-time generation of seismic bulletins. The increase in analyst resources needed to relocate an inflated number of events is compounded by failures of phase-association algorithms and a significant deterioration in the quality of underlying, fully automatic event bulletins. Current processing pipelines were designed a generation ago, and, due to computational limitations of the time, are usually limited to single passes over the raw data. With current processing capability, multiple passes over the data are feasible. Processing the raw data at each station currently generates parametric data streams thatmore » are then scanned by a phase-association algorithm to form event hypotheses. We consider the scenario in which a large earthquake has occurred and propose to define a region of likely aftershock activity in which events are detected and accurately located, using a separate specially targeted semiautomatic process. This effort may focus on so-called pattern detectors, but here we demonstrate a more general grid-search algorithm that may cover wider source regions without requiring waveform similarity. Given many well-located aftershocks within our source region, we may remove all associated phases from the original detection lists prior to a new iteration of the phase-association algorithm. We provide a proof-of-concept example for the 2015 Gorkha sequence, Nepal, recorded on seismic arrays of the International Monitoring System. Even with very conservative conditions for defining event hypotheses within the aftershock source region, we can automatically remove about half of the original detections that could have been generated by Nepal earthquakes and reduce the likelihood of false associations and spurious event hypotheses. Lastly, further reductions in the number of detections in the parametric data streams are likely, using correlation and subspace detectors and/or empirical matched field processing.« less

Iterative Strategies for Aftershock Classification in Automatic Seismic Processing Pipelines

DOE PAGES

Gibbons, Steven J.; Kvaerna, Tormod; Harris, David B.; ...

2016-06-08

We report aftershock sequences following very large earthquakes present enormous challenges to near-real-time generation of seismic bulletins. The increase in analyst resources needed to relocate an inflated number of events is compounded by failures of phase-association algorithms and a significant deterioration in the quality of underlying, fully automatic event bulletins. Current processing pipelines were designed a generation ago, and, due to computational limitations of the time, are usually limited to single passes over the raw data. With current processing capability, multiple passes over the data are feasible. Processing the raw data at each station currently generates parametric data streams thatmore » are then scanned by a phase-association algorithm to form event hypotheses. We consider the scenario in which a large earthquake has occurred and propose to define a region of likely aftershock activity in which events are detected and accurately located, using a separate specially targeted semiautomatic process. This effort may focus on so-called pattern detectors, but here we demonstrate a more general grid-search algorithm that may cover wider source regions without requiring waveform similarity. Given many well-located aftershocks within our source region, we may remove all associated phases from the original detection lists prior to a new iteration of the phase-association algorithm. We provide a proof-of-concept example for the 2015 Gorkha sequence, Nepal, recorded on seismic arrays of the International Monitoring System. Even with very conservative conditions for defining event hypotheses within the aftershock source region, we can automatically remove about half of the original detections that could have been generated by Nepal earthquakes and reduce the likelihood of false associations and spurious event hypotheses. Lastly, further reductions in the number of detections in the parametric data streams are likely, using correlation and subspace detectors and/or empirical matched field processing.« less

Nitrate and Nitrite Determination in Gunshot Residue Samples by Capillary Electrophoresis in Acidic Run Buffer.

PubMed

Erol, Özge Ö; Erdoğan, Behice Y; Onar, Atiye N

2017-03-01

Simultaneous determination of nitrate and nitrite in gunshot residue has been conducted by capillary electrophoresis using an acidic run buffer (pH 3.5). In previously developed capillary electrophoretic methods, alkaline pH separation buffers were used where nitrite and nitrate possess similar electrophoretic mobility. In this study, the electroosmotic flow has been reversed by using low pH running buffer without any additives. As a result of reversing the electroosmotic flow, very fast analysis has been actualized, well-defined and separated ion peaks emerge in less than 4 min. Besides, the limit of detection was improved by employing large volume sample stacking. Limit of detection values were 6.7 and 4.3 μM for nitrate and nitrite, respectively. In traditional procedure, mechanical agitation is employed for extraction, while in this work the extraction efficiency of ultrasound mixing for 30 min was found sufficient. The proposed method was successfully applied to authentic gunshot residue samples. © 2016 American Academy of Forensic Sciences.

Determining the 95% limit of detection for waterborne pathogen analyses from primary concentration to qPCR.

PubMed

Stokdyk, Joel P; Firnstahl, Aaron D; Spencer, Susan K; Burch, Tucker R; Borchardt, Mark A

2016-06-01

The limit of detection (LOD) for qPCR-based analyses is not consistently defined or determined in studies on waterborne pathogens. Moreover, the LODs reported often reflect the qPCR assay alone rather than the entire sample process. Our objective was to develop an approach to determine the 95% LOD (lowest concentration at which 95% of positive samples are detected) for the entire process of waterborne pathogen detection. We began by spiking the lowest concentration that was consistently positive at the qPCR step (based on its standard curve) into each procedural step working backwards (i.e., extraction, secondary concentration, primary concentration), which established a concentration that was detectable following losses of the pathogen from processing. Using the fraction of positive replicates (n = 10) at this concentration, we selected and analyzed a second, and then third, concentration. If the fraction of positive replicates equaled 1 or 0 for two concentrations, we selected another. We calculated the LOD using probit analysis. To demonstrate our approach we determined the 95% LOD for Salmonella enterica serovar Typhimurium, adenovirus 41, and vaccine-derived poliovirus Sabin 3, which were 11, 12, and 6 genomic copies (gc) per reaction (rxn), respectively (equivalent to 1.3, 1.5, and 4.0 gc L(-1) assuming the 1500 L tap-water sample volume prescribed in EPA Method 1615). This approach limited the number of analyses required and was amenable to testing multiple genetic targets simultaneously (i.e., spiking a single sample with multiple microorganisms). An LOD determined this way can facilitate study design, guide the number of required technical replicates, aid method evaluation, and inform data interpretation. Published by Elsevier Ltd.

Determining the 95% limit of detection for waterborne pathogen analyses from primary concentration to qPCR

USGS Publications Warehouse

Stokdyk, Joel P.; Firnstahl, Aaron; Spencer, Susan K.; Burch, Tucker R; Borchardt, Mark A.

2016-01-01

The limit of detection (LOD) for qPCR-based analyses is not consistently defined or determined in studies on waterborne pathogens. Moreover, the LODs reported often reflect the qPCR assay alone rather than the entire sample process. Our objective was to develop an approach to determine the 95% LOD (lowest concentration at which 95% of positive samples are detected) for the entire process of waterborne pathogen detection. We began by spiking the lowest concentration that was consistently positive at the qPCR step (based on its standard curve) into each procedural step working backwards (i.e., extraction, secondary concentration, primary concentration), which established a concentration that was detectable following losses of the pathogen from processing. Using the fraction of positive replicates (n = 10) at this concentration, we selected and analyzed a second, and then third, concentration. If the fraction of positive replicates equaled 1 or 0 for two concentrations, we selected another. We calculated the LOD using probit analysis. To demonstrate our approach we determined the 95% LOD for Salmonella enterica serovar Typhimurium, adenovirus 41, and vaccine-derived poliovirus Sabin 3, which were 11, 12, and 6 genomic copies (gc) per reaction (rxn), respectively (equivalent to 1.3, 1.5, and 4.0 gc L−1 assuming the 1500 L tap-water sample volume prescribed in EPA Method 1615). This approach limited the number of analyses required and was amenable to testing multiple genetic targets simultaneously (i.e., spiking a single sample with multiple microorganisms). An LOD determined this way can facilitate study design, guide the number of required technical replicates, aid method evaluation, and inform data interpretation.

Salmonella Typhi and Salmonella Paratyphi A elaborate distinct systemic metabolite signatures during enteric fever

PubMed Central

Näsström, Elin; Vu Thieu, Nga Tran; Dongol, Sabina; Karkey, Abhilasha; Voong Vinh, Phat; Ha Thanh, Tuyen; Johansson, Anders; Arjyal, Amit; Thwaites, Guy; Dolecek, Christiane; Basnyat, Buddha; Baker, Stephen; Antti, Henrik

2014-01-01

The host–pathogen interactions induced by Salmonella Typhi and Salmonella Paratyphi A during enteric fever are poorly understood. This knowledge gap, and the human restricted nature of these bacteria, limit our understanding of the disease and impede the development of new diagnostic approaches. To investigate metabolite signals associated with enteric fever we performed two dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC/TOFMS) on plasma from patients with S. Typhi and S. Paratyphi A infections and asymptomatic controls, identifying 695 individual metabolite peaks. Applying supervised pattern recognition, we found highly significant and reproducible metabolite profiles separating S. Typhi cases, S. Paratyphi A cases, and controls, calculating that a combination of six metabolites could accurately define the etiological agent. For the first time we show that reproducible and serovar specific systemic biomarkers can be detected during enteric fever. Our work defines several biologically plausible metabolites that can be used to detect enteric fever, and unlocks the potential of this method in diagnosing other systemic bacterial infections. DOI: http://dx.doi.org/10.7554/eLife.03100.001 PMID:24902583

The Molecular Revolution in Cutaneous Biology: Era of Molecular Diagnostics for Inherited Skin Diseases.

PubMed

McGrath, John A

2017-05-01

The discovery of pathogenic mutations in inherited skin diseases represents one of the major landmarks of late 20th century molecular genetics. Mutation data can provide accurate diagnoses, improve genetic counseling, help define disease mechanisms, establish disease models, and provide a basis for translational research and testing of novel therapeutics. The process of detecting disease mutations, however, has not always been straightforward. Traditional approaches using genetic linkage or candidate gene analysis have often been limited, costly, and slow to yield new insights, but the advent of next-generation sequencing (NGS) technologies has altered the landscape of current gene discovery and mutation detection approaches. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

Study to define low voltage and low temperature operating limits of the Pioneer 10/11 Meteoroid Detection Equipment (MDE) system

NASA Technical Reports Server (NTRS)

Parker, C. D.

1975-01-01

The Pioneer 10/11 meteoroid detection equipment (MDE) pressure cells were tested at liquid nitrogen (LN2) and liquid helium (LHe) temperatures with the excitation voltage controlled as a parameter. The cells failed by firing because of pressurizing gas condensation as the temperature was lowered from LN2 to LHe temperature and when raised from LHe temperature. A study was conducted to determine cell pressure as a function of temperature, and cell failure was estimated as a function of temperature and excitation voltage. The electronic system was also studied, and a profile of primary spacecraft voltage (nominally 28 Vdc) and temperature corresponding to electronic system failure was determined experimentally.

Atrial fibrillation driver mechanisms: Insight from the isolated human heart.

PubMed

Csepe, Thomas A; Hansen, Brian J; Fedorov, Vadim V

2017-01-01

Although there have been great technological advances in the treatment of atrial fibrillation (AF), current therapies remain limited due to a narrow understanding of AF mechanisms in the human heart. This review will highlight our recent studies on explanted human hearts where we developed and employed a novel functional-structural mapping approach by integrating high-resolution simultaneous endo-epicardial and panoramic optical mapping with 3D gadolinium-enhanced MRI to define the spatiotemporal characteristics of AF drivers and their structural substrates. The results allow us to postulate that the primary mechanism of AF maintenance in human hearts is a limited number of localized intramural microanatomic reentrant AF drivers anchored to heart-specific 3D fibrotically insulated myobundle tracks, which may remain hidden to clinical single-surface electrode mapping. We suggest that ex vivo human heart studies, by using an integrated 3D functional and structural mapping approach, will help to reveal defining features of AF drivers as well as validate and improve clinical approaches to detect and target these AF drivers in patients with cardiac diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

Electrochemical detection of aqueous Ag+ based on Ag+-assisted ligation reaction

NASA Astrophysics Data System (ADS)

Miao, Peng; Han, Kun; Wang, Bidou; Luo, Gangyin; Wang, Peng; Chen, Mingli; Tang, Yuguo

2015-03-01

In this work, a novel strategy to fabricate a highly sensitive and selective biosensor for the detection of Ag+ is proposed. Two DNA probes are designed and modified on a gold electrode surface by gold-sulfur chemistry and hybridization. In the presence of Ag+, cytosine-Ag+-cytosine composite forms and facilitates the ligation event on the electrode surface, which can block the release of electrochemical signals labeled on one of the two DNA probes during denaturation process. Ag+ can be sensitively detected with the detection limit of 0.1 nM, which is much lower than the toxicity level defined by U.S. Environmental Protection Agency. This biosensor can easily distinguish Ag+ from other interfering ions and the performances in real water samples are also satisfactory. Moreover, the two DNA probes are designed to contain the recognition sequences of a nicking endonuclease, and the ligated DNA can thus be cleaved at the original site. Therefore, the electrode can be regenerated, which allows the biosensor to be reused for additional tests.

Electrochemical detection of phenolic estrogenic compounds at clay modified carbon paste electrode

NASA Astrophysics Data System (ADS)

Belkamssa, N.; Ouattara, L.; Kawachi, A.; Tsujimura, M.; Isoda, H.; Chtaini, A.; Ksibi, M.

2015-04-01

A simple and sensitive electroanalytical method was developed to determine the Endocrine Disrupting chemical 4-tert-octylphenol on clay modified carbon paste electrode (Clay/CPE). The electrochemical response of the proposed electrode was studied by means of cyclic and square wave voltammetry. It has found that the oxidation of 4-tert-octylphenol on the clay/CPE displayed a well-defined oxidation peak. Under these optimal conditions, a linear relation between concentrations of 4-tert-octylphenol current response was obtained over range of 7.26×10-6 to 3.87×10-7 with a detection and quantification limit of 9.2×10-7 M and 3.06×10-6 M, respectively. The correlation coefficient is 0.9963. The modified electrode showed suitable sensitivity, high stability and an accurate detection of 4-tert-octylphenol. The modified electrode also relevant suitable selectivity for various phenolic estrogenic compounds.

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

Wu, Meiye; Davis, Ryan Wesley; Hatch, Anson

In the early stages of infection, patients develop non-specific or no symptoms at all. While waiting for identification of the infectious agent, precious window of opportunity for early intervention is lost. The standard diagnostics require affinity reagents and sufficient pathogen titers to reach the limit of detection. In the event of a disease outbreak, triaging the at-risk population rapidly and reliably for quarantine and countermeasure is more important than the identification of the pathogen by name. To expand Sandia's portfolio of Biological threat management capabilities, we will utilize Raman spectrometry to analyze immune subsets in whole blood to rapidly distinguishmore » infected from non-infected, and bacterial from viral infection, for the purpose of triage during an emergency outbreak. The goal of this one year LDRD is to determine whether Raman spectroscopy can provide label-free detection of early disease signatures, and define a miniaturized Raman detection system meeting requirements for low- resource settings.« less

Rapid analysis of clenbuterol, salbutamol, procaterol, and fenoterol in pharmaceuticals and human urine by capillary electrophoresis.

PubMed

Sirichai, Somsak; Khanatharana, Proespichaya

2008-09-15

Capillary electrophoresis (CE) with UV detection for the simultaneous and short-time analysis of clenbuterol, salbutamol, procaterol, fenoterol is described and validated. Optimized conditions were found to be a 10 mmoll(-1) borate buffer (pH 10.0), an separation voltage of 19 kV, and a separation temperature of 32 degrees C. Detection was set at 205 nm. Under the optimized conditions, analyses of the four analytes in pharmaceutical and human urine samples were carried out in approximately 1 min. The interference of the sample matrix was not observed. The LOD (limits of detection) defined at S/N of 3:1 was found between 0.5 and 2.0 mgl(-1) for the analytes. The linearity of the detector response was within the range from 2.0 to 30 mgl(-1) with correlation coefficient >0.996.

High-Level Data Races

NASA Technical Reports Server (NTRS)

Artho, Cyrille; Havelund, Klaus; Biere, Armin; Koga, Dennis (Technical Monitor)

2003-01-01

Data races are a common problem in concurrent and multi-threaded programming. They are hard to detect without proper tool support. Despite the successful application of these tools, experience shows that the notion of data race is not powerful enough to capture certain types of inconsistencies occurring in practice. In this paper we investigate data races on a higher abstraction layer. This enables us to detect inconsistent uses of shared variables, even if no classical race condition occurs. For example, a data structure representing a coordinate pair may have to be treated atomically. By lifting the meaning of a data race to a higher level, such problems can now be covered. The paper defines the concepts view and view consistency to give a notation for this novel kind of property. It describes what kinds of errors can be detected with this new definition, and where its limitations are. It also gives a formal guideline for using data structures in a multi-threading environment.

The detection and stabilisation of limit cycle for deterministic finite automata

NASA Astrophysics Data System (ADS)

Han, Xiaoguang; Chen, Zengqiang; Liu, Zhongxin; Zhang, Qing

2018-04-01

In this paper, the topological structure properties of deterministic finite automata (DFA), under the framework of the semi-tensor product of matrices, are investigated. First, the dynamics of DFA are converted into a new algebraic form as a discrete-time linear system by means of Boolean algebra. Using this algebraic description, the approach of calculating the limit cycles of different lengths is given. Second, we present two fundamental concepts, namely, domain of attraction of limit cycle and prereachability set. Based on the prereachability set, an explicit solution of calculating domain of attraction of a limit cycle is completely characterised. Third, we define the globally attractive limit cycle, and then the necessary and sufficient condition for verifying whether all state trajectories of a DFA enter a given limit cycle in a finite number of transitions is given. Fourth, the problem of whether a DFA can be stabilised to a limit cycle by the state feedback controller is discussed. Criteria for limit cycle-stabilisation are established. All state feedback controllers which implement the minimal length trajectories from each state to the limit cycle are obtained by using the proposed algorithm. Finally, an illustrative example is presented to show the theoretical results.

Simple and rapid chemiluminescence aptasensor for Hg2+ in contaminated samples: A new signal amplification mechanism.

PubMed

Qi, Yingying; Xiu, Fu-Rong; Yu, Gending; Huang, Lili; Li, Baoxin

2017-01-15

Detection of ultralow concentration of heavy metal ion Hg 2+ is important for human health protection and environment monitoring because of the gradual accumulation in environmental and biological fields. Herein, we report a convenient chemiluminescence (CL) biosensing platform for ultrasensitive Hg 2+ detection by signal amplification mechanism from positively charged gold nanoparticles ((+)AuNPs). It is based on (+)AuNPs charge effect and aptamer conformation change induced by target to stimulate the generation of CL in the presence of H 2 O 2 and luminol without high salt medium. Notably particularly, the typical problem of the high salt medium from (-) AuNPs system, like influencing aptamers' bind with target and hindering CL reaction can be effectively addressed through the direct introduction of (+)AuNPs. Therefore, the proposed biosensing exhibits a high sensitivity toward target Hg 2+ with a detection limit of 16 pM, which is far below the limit (10nM) defined by the U.S. Environmental Protection Agency in drinkable water, and is about 10-fold lower than the previously reported aptamer-based assays for Hg 2+ . This sensing platform provides a simple, rapid, and cost-effective approach for label-free sensitive detection of Hg 2+ . Moreover, it is universal for the detection of other targets. Undoubtedly, such a direct utilizing of (+)AuNPs' charge effect will provide a new signal amplification way for label-free aptamer-based CL analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

The potential of three different PCR-related approaches for the authentication of mixtures of herbal substances and finished herbal medicinal products.

PubMed

Doganay-Knapp, Kirsten; Orland, Annika; König, Gabriele M; Knöss, Werner

2018-04-01

Herbal substances and preparations thereof play an important role in healthcare systems worldwide. Due to the variety of these products regarding origin, composition and processing procedures, appropriate methodologies for quality assessment need to be considered. A majority of herbal substances is administered as multicomponent mixtures, especially in the field of Traditional Chinese Medicine and ayurvedic medicine, but also in finished medicinal products. Quality assessment of complex mixtures of herbal substances with conventional methods is challenging. Thus, emphasis of the present work was directed on the development of complementary methods to elucidate the composition of mixtures of herbal substances and finished herbal medicinal products. An indispensable prerequisite for the safe and effective use of herbal medicines is the unequivocal authentication of the medicinal plants used therein. In this context, we investigated the potential of three different PCR-related methods in the characterization and authentication of herbal substances. A multiplex PCR assay and a quantitative PCR (qPCR) assay were established to analyze defined mixtures of the herbal substances Quercus cortex, Juglandis folium, Aristolochiae herba, Matricariae flos and Salviae miltiorrhizae radix et rhizoma and a finished herbal medicinal product. Furthermore, a standard cloning approach using universal primers targeting the ITS region was established in order to allow the investigation of herbal mixtures with unknown content. The cloning approach had some limitations regarding the detection/recovery of the components in defined mixtures of herbal substances, but the complementary use of two sets of universal primer pairs increased the detection of components out of the mixture. While the multiplex PCR did not retrace all components in the defined mixtures of herbal substances, the established qPCR resulted in simultaneous and specific detection of the five target sequences in all defined mixtures. These data indicate that for authentication purposes, complementary PCR-related methods are highly recommendable for the analysis of herbal mixtures in parallel. Copyright © 2018 Elsevier GmbH. All rights reserved.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of 86 volatile organic compounds in water by gas chromatography/mass spectrometry, including detections less than reporting limits

USGS Publications Warehouse

Connor, Brooke F.; Rose, Donna L.; Noriega, Mary C.; Murtaugh, Lucinda K.; Abney, Sonja R.

1998-01-01

This report presents precision and accuracy data for volatile organic compounds (VOCs) in the nanogram-per-liter range, including aromatic hydrocarbons, reformulated fuel components, and halogenated hydrocarbons using purge and trap capillary-column gas chromatography/mass spectrometry. One-hundred-four VOCs were initially tested. Of these, 86 are suitable for determination by this method. Selected data are provided for the 18 VOCs that were not included. This method also allows for the reporting of semiquantitative results for tentatively identified VOCs not included in the list of method compounds. Method detection limits, method performance data, preservation study results, and blank results are presented. The authors describe a procedure for reporting low-concentration detections at less than the reporting limit. The nondetection value (NDV) is introduced as a statistically defined reporting limit designed to limit false positives and false negatives to less than 1 percent. Nondetections of method compounds are reported as ?less than NDV.? Positive detections measured at less than NDV are reported as estimated concentrations to alert the data user to decreased confidence in accurate quantitation. Instructions are provided for analysts to report data at less than the reporting limits. This method can support the use of either method reporting limits that censor detections at lower concentrations or the use of NDVs as reporting limits. The data-reporting strategy for providing analytical results at less than the reporting limit is a result of the increased need to identify the presence or absence of environmental contaminants in water samples at increasingly lower concentrations. Long-term method detection limits (LTMDLs) for 86 selected compounds range from 0.013 to 2.452 micrograms per liter (?g/L) and differ from standard method detection limits (MDLs) in that the LTMDLs include the long-term variance of multiple instruments, multiple operators, and multiple calibrations over a longer time. For these reasons, LTMDLs are expected to be slightly higher than standard MDLs. Recoveries for all of the VOCs tested ranged from 36 (tert-butyl formate) to 155 percent (pentachlorobenzene). The majority of the compounds ranged from 85 to 115 percent recovery and had less than 5 percent relative standard deviation for concentrations spiked between 1 to 500 ?g/L in volatile blank-, surface-, and ground-water samples. Recoveries of 60 set spikes at low concentrations ranged from 70 to 114 percent (1,2,3- trimethylbenzene and acetone). Recovery data were collected over 6 months with multiple instruments, operators, and calibrations. In this method, volatile organic compounds are extracted from a water sample by actively purging with helium. The VOCs are collected onto a sorbent trap, thermally desorbed, separated by a Megabore gas chromatographic capillary column, and finally determined by a full-scan quadrupole mass spectrometer. Compound identification is confirmed by the gas chromatographic retention time and by the resultant mass spectrum, typically identified by three unique ions. An unknown compound detected in a sample can be tentatively identified by comparing the unknown mass spectrum to reference spectra in the mass-spectra computer-data system library compiled by the National Institute of Standards and Technology.

Stroke penumbra defined by an MRI-based oxygen challenge technique: 1. Validation using [14C]2-deoxyglucose autoradiography.

PubMed

Robertson, Craig A; McCabe, Christopher; Gallagher, Lindsay; Lopez-Gonzalez, Maria del Rosario; Holmes, William M; Condon, Barrie; Muir, Keith W; Santosh, Celestine; Macrae, I Mhairi

2011-08-01

Accurate identification of ischemic penumbra will improve stroke patient selection for reperfusion therapies and clinical trials. Current magnetic resonance imaging (MRI) techniques have limitations and lack validation. Oxygen challenge T(2)(*) MRI (T(2)(*) OC) uses oxygen as a biotracer to detect tissue metabolism, with penumbra displaying the greatest T(2)(*) signal change during OC. [(14)C]2-deoxyglucose (2-DG) autoradiography was combined with T(2)(*) OC to determine metabolic status of T(2)(*)-defined penumbra. Permanent middle cerebral artery occlusion was induced in anesthetized male Sprague-Dawley rats (n=6). Ischemic injury and perfusion deficit were determined by diffusion- and perfusion-weighted imaging, respectively. At 147 ± 32 minutes after stroke, T(2)(*) signal change was measured during a 5-minute 100% OC, immediately followed by 125 μCi/kg 2-DG, intravenously. Magnetic resonance images were coregistered with the corresponding autoradiograms. Regions of interest were located within ischemic core, T(2)(*)-defined penumbra, equivalent contralateral structures, and a region of hyperglycolysis. A T(2)(*) signal increase of 9.22% ± 3.9% (mean ± s.d.) was recorded in presumed penumbra, which displayed local cerebral glucose utilization values equivalent to contralateral cortex. T(2)(*) signal change was negligible in ischemic core, 3.2% ± 0.78% in contralateral regions, and 1.41% ± 0.62% in hyperglycolytic tissue, located outside OC-defined penumbra and within the diffusion abnormality. The results support the utility of OC-MRI to detect viable penumbral tissue following stroke.

Reverse transcriptase polymerase chain reaction on fine needle aspirates for rapid detection of translocations in synovial sarcoma.

PubMed

Nilsson, G; Wang, M; Wejde, J; Kanter, L; Karlén, J; Tani, E; Kreicbergs, A; Larsson, O

1998-01-01

To evaluate the utilization of fine needle aspiration (FNA) biopsy to obtain material for reverse-transcriptase polymerase chain reaction (RT-PCR) in the detection of the t(X;18)(p11.2;q11.2) translocation in synovial sarcomas. We applied RT-PCR to detection of synovial sarcoma fusion gene transcripts on fine needle aspirates. Five clinical samples were first analyzed: one was a tumor previously diagnosed as malignant hemangiopericytoma, one was a poorly defined tumor, and three were suspected synovial sarcomas. FNA material was transferred directly to the RT-PCR reaction tube without RNA extraction. The t(X;18) translocation could be detected on the limited amount of material that FNA provides. In each of the cases studied the representivity of the tumor samples was confirmed microscopically. Our protocol permits analysis directly on representative samples without extraction of RNA. The results imply that RT-PCR offers reliable detection of sarcoma fusion gene transcripts on fine needle aspirates. The procedure, apart from being applicable to outpatients, is rapid and sensitive.

Development of a PCR Assay to Detect Low Level Trypanosoma cruzi in Blood Specimens Collected with PAXgene Blood DNA Tubes for Clinical Trials Treating Chagas Disease.

PubMed

Wei, Bo; Chen, Lei; Kibukawa, Miho; Kang, John; Waskin, Hetty; Marton, Matthew

2016-12-01

Chagas disease is caused by the parasitic infection of Trypanosoma cruzi (T. cruzi). The STOP CHAGAS clinical trial was initiated in 2011 to evaluate posaconazole in treating Chagas disease, with treatment success defined as negative qualitative PCR results of detecting the parasites in blood specimens collected post-treatment. PAXgene Blood DNA tubes were utilized as a simple procedure to collect and process blood specimens. However, the PAXgene blood specimens challenged published T. cruzi PCR methods, resulting in poor sensitivity and reproducibility. To accurately evaluate the treatment efficacy of the clinical study, we developed and validated a robust PCR assay for detecting low level T. cruzi in PAXgene blood specimens. The assay combines a new DNA extraction method with a custom designed qPCR assay, resulting in limit of detection of 0.005 and 0.01 fg/μl for K98 and CL Brener, two representative strains of two of T. cruzi's discrete typing units. Reliable qPCR standard curves were established for both strains to measure parasite loads, with amplification efficiency ≥ 90% and the lower limit of linearity ≥ 0.05 fg/μl. The assay successfully analyzed the samples collected from the STOP CHAGAS study and may prove useful for future global clinical trials evaluating new therapies for asymptomatic chronic Chagas disease.

FERMI/LAT OBSERVATIONS OF SWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC {gamma}-RAY BACKGROUND

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

Teng, Stacy H.; Mushotzky, Richard F.; Reynolds, Christopher S.

2011-12-01

We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R{sub X,BAT} where radio-loud objects have log R{sub X,BAT} > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be {approx}2 Multiplication-Sign 10{supmore » -11} photons cm{sup -2} s{sup -1}, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the {gamma}-ray (1-100 GeV) luminosity of {approx}< 3 Multiplication-Sign 10{sup 41} erg s{sup -1}. In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.« less

Randomized Prediction Games for Adversarial Machine Learning.

PubMed

Rota Bulo, Samuel; Biggio, Battista; Pillai, Ignazio; Pelillo, Marcello; Roli, Fabio

In spam and malware detection, attackers exploit randomization to obfuscate malicious data and increase their chances of evading detection at test time, e.g., malware code is typically obfuscated using random strings or byte sequences to hide known exploits. Interestingly, randomization has also been proposed to improve security of learning algorithms against evasion attacks, as it results in hiding information about the classifier to the attacker. Recent work has proposed game-theoretical formulations to learn secure classifiers, by simulating different evasion attacks and modifying the classification function accordingly. However, both the classification function and the simulated data manipulations have been modeled in a deterministic manner, without accounting for any form of randomization. In this paper, we overcome this limitation by proposing a randomized prediction game, namely, a noncooperative game-theoretic formulation in which the classifier and the attacker make randomized strategy selections according to some probability distribution defined over the respective strategy set. We show that our approach allows one to improve the tradeoff between attack detection and false alarms with respect to the state-of-the-art secure classifiers, even against attacks that are different from those hypothesized during design, on application examples including handwritten digit recognition, spam, and malware detection.In spam and malware detection, attackers exploit randomization to obfuscate malicious data and increase their chances of evading detection at test time, e.g., malware code is typically obfuscated using random strings or byte sequences to hide known exploits. Interestingly, randomization has also been proposed to improve security of learning algorithms against evasion attacks, as it results in hiding information about the classifier to the attacker. Recent work has proposed game-theoretical formulations to learn secure classifiers, by simulating different evasion attacks and modifying the classification function accordingly. However, both the classification function and the simulated data manipulations have been modeled in a deterministic manner, without accounting for any form of randomization. In this paper, we overcome this limitation by proposing a randomized prediction game, namely, a noncooperative game-theoretic formulation in which the classifier and the attacker make randomized strategy selections according to some probability distribution defined over the respective strategy set. We show that our approach allows one to improve the tradeoff between attack detection and false alarms with respect to the state-of-the-art secure classifiers, even against attacks that are different from those hypothesized during design, on application examples including handwritten digit recognition, spam, and malware detection.

Electrochemical Genosensor To Detect Pathogenic Bacteria (Escherichia coli O157:H7) As Applied in Real Food Samples (Fresh Beef) To Improve Food Safety and Quality Control.

PubMed

Abdalhai, Mandour H; Fernandes, António Maximiano; Xia, Xiaofeng; Musa, Abubakr; Ji, Jian; Sun, Xiulan

2015-05-27

The electrochemical genosensor is one of the most promising methods for the rapid and reliable detection of pathogenic bacteria. In a previous work, we performed an efficient electrochemical genosensor detection of Staphylococcus aureus by using lead sulfide nanoparticles (PbSNPs). As a continuation of this study, in the present work, the electrochemical genosensor was used to detect Escherichia coli O157:H7. The primer and probes were designed using NCBI database and Sigma-Aldrich primer and probe software. The capture and signalizing probes were modified by thiol (SH) and amine (NH2), respectively. Then, the signalizing probe was connected using cadmium sulfide nanoparticles (CdSNPs), which showed well-defined peaks after electrochemical detection. The genosensor was prepared by immobilization of complementary DNA on the gold electrode surface, which hybridizes with a specific fragment gene from pathogenic to make a sandwich structure. The conductivity and sensitivity of the sensor were increased by using multiwalled carbon nanotubes (MWCNT) that had been modified using chitosan deposited as a thin layer on the glass carbon electrode (GCE) surface, followed by a deposit of bismuth. The peak currents of E. coli O157:H7 correlated in a linear fashion with the concentration of tDNA. The detection limit was 1.97 × 10(-14) M, and the correlation coefficient was 0.989. A poorly defined current response was observed as the negative control and baseline. Our results showed high sensitivity and selectivity of the electrochemical DNA biosensor to the pathogenic bacteria E. coli O157:H7. The biosensor was also used to evaluate the detection of pathogen in real beef samples contaminated artificially. Compared with other electrochemical DNA biosensors, we conclude that this genosensor provides for very efficient detection of pathogenic bacteria. Therefore, this method may have potential application in food safety and related fields.

In-fiber Fabry-Perot refractometer assisted by a long-period grating.

PubMed

Mosquera, L; Sáez-Rodriguez, D; Cruz, J L; Andrés, M V

2010-02-15

We present an optical fiber refractometer based on a Fabry-Perot interferometer defined by two fiber Bragg gratings and an intracavity long-period grating that makes the light confined in the resonator interact with the surrounding medium. The external refractive index is monitored by the resonant frequencies of the Fabry-Perot interferometer, which can be measured either in transmission or in reflection. In this first experiment, wavelength shifts measured with a resolution of 0.1 pm have allowed one to establish a refractive index detection limit of 2.1x10(-5).

Direct electrochemistry and electrocatalysis of hemoglobin in graphene oxide and ionic liquid composite film.

PubMed

Sun, Wei; Gong, Shixing; Shi, Fan; Cao, Lili; Ling, Luyang; Zheng, Weizhe; Wang, Wencheng

2014-07-01

In this paper a novel sensing platform based on graphene oxide (GO), ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate and Nafion for the immobilization of hemoglobin (Hb) was adopted with a carbon ionic liquid electrode (CILE) as the substrate electrode, which was denoted as Nafion/Hb-GO-IL/CILE. Spectroscopic results suggested that Hb molecules were not denatured in the composite. A pair of well-defined redox peaks appeared on the cyclic voltammogram, which was attributed to the realization of direct electron transfer of Hb on the electrode. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with the electrochemical parameters calculated. Based on the catalytic ability of the immobilized Hb, Nafion/Hb-GO-IL/CILE exhibited excellent electrocatalytic behavior towards the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.01 to 40.0mM with the detection limit as 3.12 μM (3σ), H2O2 in the concentration range from 0.08 to 635.0 μM with the detection limit as 0.0137 μM (3σ) and NaNO2 in the concentration range from 0.5 to 800.0 μM with the detection limit as 0.0104 μM (3σ). So the proposed bioelectrode could be served as a new third-generation electrochemical sensor without mediator. Copyright © 2014 Elsevier B.V. All rights reserved.

A novel fluorescence-based assay for the rapid detection and quantification of cellular deoxyribonucleoside triphosphates

PubMed Central

Wilson, Peter M.; LaBonte, Melissa J.; Russell, Jared; Louie, Stan; Ghobrial, Andrew A.; Ladner, Robert D.

2011-01-01

Current methods for measuring deoxyribonucleoside triphosphates (dNTPs) employ reagent and labor-intensive assays utilizing radioisotopes in DNA polymerase-based assays and/or chromatography-based approaches. We have developed a rapid and sensitive 96-well fluorescence-based assay to quantify cellular dNTPs utilizing a standard real-time PCR thermocycler. This assay relies on the principle that incorporation of a limiting dNTP is required for primer-extension and Taq polymerase-mediated 5–3′ exonuclease hydrolysis of a dual-quenched fluorophore-labeled probe resulting in fluorescence. The concentration of limiting dNTP is directly proportional to the fluorescence generated. The assay demonstrated excellent linearity (R2 > 0.99) and can be modified to detect between ∼0.5 and 100 pmol of dNTP. The limits of detection (LOD) and quantification (LOQ) for all dNTPs were defined as <0.77 and <1.3 pmol, respectively. The intra-assay and inter-assay variation coefficients were determined to be <4.6% and <10%, respectively with an accuracy of 100 ± 15% for all dNTPs. The assay quantified intracellular dNTPs with similar results obtained from a validated LC–MS/MS approach and successfully measured quantitative differences in dNTP pools in human cancer cells treated with inhibitors of thymidylate metabolism. This assay has important application in research that investigates the influence of pathological conditions or pharmacological agents on dNTP biosynthesis and regulation. PMID:21576234

Creation of an Accurate Algorithm to Detect Snellen Best Documented Visual Acuity from Ophthalmology Electronic Health Record Notes.

PubMed

Mbagwu, Michael; French, Dustin D; Gill, Manjot; Mitchell, Christopher; Jackson, Kathryn; Kho, Abel; Bryar, Paul J

2016-05-04

Visual acuity is the primary measure used in ophthalmology to determine how well a patient can see. Visual acuity for a single eye may be recorded in multiple ways for a single patient visit (eg, Snellen vs. Jäger units vs. font print size), and be recorded for either distance or near vision. Capturing the best documented visual acuity (BDVA) of each eye in an individual patient visit is an important step for making electronic ophthalmology clinical notes useful in research. Currently, there is limited methodology for capturing BDVA in an efficient and accurate manner from electronic health record (EHR) notes. We developed an algorithm to detect BDVA for right and left eyes from defined fields within electronic ophthalmology clinical notes. We designed an algorithm to detect the BDVA from defined fields within 295,218 ophthalmology clinical notes with visual acuity data present. About 5668 unique responses were identified and an algorithm was developed to map all of the unique responses to a structured list of Snellen visual acuities. Visual acuity was captured from a total of 295,218 ophthalmology clinical notes during the study dates. The algorithm identified all visual acuities in the defined visual acuity section for each eye and returned a single BDVA for each eye. A clinician chart review of 100 random patient notes showed a 99% accuracy detecting BDVA from these records and 1% observed error. Our algorithm successfully captures best documented Snellen distance visual acuity from ophthalmology clinical notes and transforms a variety of inputs into a structured Snellen equivalent list. Our work, to the best of our knowledge, represents the first attempt at capturing visual acuity accurately from large numbers of electronic ophthalmology notes. Use of this algorithm can benefit research groups interested in assessing visual acuity for patient centered outcome. All codes used for this study are currently available, and will be made available online at https://phekb.org.

Creation of an Accurate Algorithm to Detect Snellen Best Documented Visual Acuity from Ophthalmology Electronic Health Record Notes

PubMed Central

French, Dustin D; Gill, Manjot; Mitchell, Christopher; Jackson, Kathryn; Kho, Abel; Bryar, Paul J

2016-01-01

Background Visual acuity is the primary measure used in ophthalmology to determine how well a patient can see. Visual acuity for a single eye may be recorded in multiple ways for a single patient visit (eg, Snellen vs. Jäger units vs. font print size), and be recorded for either distance or near vision. Capturing the best documented visual acuity (BDVA) of each eye in an individual patient visit is an important step for making electronic ophthalmology clinical notes useful in research. Objective Currently, there is limited methodology for capturing BDVA in an efficient and accurate manner from electronic health record (EHR) notes. We developed an algorithm to detect BDVA for right and left eyes from defined fields within electronic ophthalmology clinical notes. Methods We designed an algorithm to detect the BDVA from defined fields within 295,218 ophthalmology clinical notes with visual acuity data present. About 5668 unique responses were identified and an algorithm was developed to map all of the unique responses to a structured list of Snellen visual acuities. Results Visual acuity was captured from a total of 295,218 ophthalmology clinical notes during the study dates. The algorithm identified all visual acuities in the defined visual acuity section for each eye and returned a single BDVA for each eye. A clinician chart review of 100 random patient notes showed a 99% accuracy detecting BDVA from these records and 1% observed error. Conclusions Our algorithm successfully captures best documented Snellen distance visual acuity from ophthalmology clinical notes and transforms a variety of inputs into a structured Snellen equivalent list. Our work, to the best of our knowledge, represents the first attempt at capturing visual acuity accurately from large numbers of electronic ophthalmology notes. Use of this algorithm can benefit research groups interested in assessing visual acuity for patient centered outcome. All codes used for this study are currently available, and will be made available online at https://phekb.org. PMID:27146002

Validating the WHO maternal near miss tool: comparing high- and low-resource settings.

PubMed

Witteveen, Tom; Bezstarosti, Hans; de Koning, Ilona; Nelissen, Ellen; Bloemenkamp, Kitty W; van Roosmalen, Jos; van den Akker, Thomas

2017-06-19

WHO proposed the WHO Maternal Near Miss (MNM) tool, classifying women according to several (potentially) life-threatening conditions, to monitor and improve quality of obstetric care. The objective of this study is to analyse merged data of one high- and two low-resource settings where this tool was applied and test whether the tool may be suitable for comparing severe maternal outcome (SMO) between these settings. Using three cohort studies that included SMO cases, during two-year time frames in the Netherlands, Tanzania and Malawi we reassessed all SMO cases (as defined by the original studies) with the WHO MNM tool (five disease-, four intervention- and seven organ dysfunction-based criteria). Main outcome measures were prevalence of MNM criteria and case fatality rates (CFR). A total of 3172 women were studied; 2538 (80.0%) from the Netherlands, 248 (7.8%) from Tanzania and 386 (12.2%) from Malawi. Total SMO detection was 2767 (87.2%) for disease-based criteria, 2504 (78.9%) for intervention-based criteria and 1211 (38.2%) for organ dysfunction-based criteria. Including every woman who received ≥1 unit of blood in low-resource settings as life-threatening, as defined by organ dysfunction criteria, led to more equally distributed populations. In one third of all Dutch and Malawian maternal death cases, organ dysfunction criteria could not be identified from medical records. Applying solely organ dysfunction-based criteria may lead to underreporting of SMO. Therefore, a tool based on defining MNM only upon establishing organ failure is of limited use for comparing settings with varying resources. In low-resource settings, lowering the threshold of transfused units of blood leads to a higher detection rate of MNM. We recommend refined disease-based criteria, accompanied by a limited set of intervention- and organ dysfunction-based criteria to set a measure of severity.

Application of biomarkers in cancer risk management: evaluation from stochastic clonal evolutionary and dynamic system optimization points of view.

PubMed

Li, Xiaohong; Blount, Patricia L; Vaughan, Thomas L; Reid, Brian J

2011-02-01

Aside from primary prevention, early detection remains the most effective way to decrease mortality associated with the majority of solid cancers. Previous cancer screening models are largely based on classification of at-risk populations into three conceptually defined groups (normal, cancer without symptoms, and cancer with symptoms). Unfortunately, this approach has achieved limited successes in reducing cancer mortality. With advances in molecular biology and genomic technologies, many candidate somatic genetic and epigenetic "biomarkers" have been identified as potential predictors of cancer risk. However, none have yet been validated as robust predictors of progression to cancer or shown to reduce cancer mortality. In this Perspective, we first define the necessary and sufficient conditions for precise prediction of future cancer development and early cancer detection within a simple physical model framework. We then evaluate cancer risk prediction and early detection from a dynamic clonal evolution point of view, examining the implications of dynamic clonal evolution of biomarkers and the application of clonal evolution for cancer risk management in clinical practice. Finally, we propose a framework to guide future collaborative research between mathematical modelers and biomarker researchers to design studies to investigate and model dynamic clonal evolution. This approach will allow optimization of available resources for cancer control and intervention timing based on molecular biomarkers in predicting cancer among various risk subsets that dynamically evolve over time.

DNA markers in molecular diagnostics for hepatocellular carcinoma

PubMed Central

Su, Ying-Hsiu; Lin, Selena Y; Song, Wei; Jain, Surbhi

2015-01-01

Hepatocellular carcinoma (HCC) is the one of the leading causes of cancer mortality in the world, mainly due to the difficulty of early detection and limited therapeutic options. The implementation of HCC surveillance programs in well-defined, high-risk populations were only able to detect about 40–50% of HCC at curative stages (Barcelona Clinic Liver Cancer stages 0 & 1) due to the low sensitivities of the current screening methods. The advance of sequencing technologies has identified numerous modifications as potential candidate DNA markers for diagnosis/surveillance. Here we aim to provide an overview of the DNA alterations that result in activation of cancer pathways known to potentially drive HCC carcinogenesis and to summarize performance characteristics of each DNA marker in the periphery (blood or urine) for HCC screening. PMID:25098554

On the spatial coordinate measurement of two identical particles

NASA Astrophysics Data System (ADS)

Marchewka, Avi; Granot, Er'el; Schuss, Zeev

2016-04-01

Theoretically, the coordinate measurement of two identical particles at a point by two narrowly separated narrow detectors, is interpreted in the limit of shrinking width and separation, as the detection of two particles by a single narrow detector. Ordinarily, the ratio between probabilities of point measurements is independent of the width of the narrow detectors. We show here that not only this is not the case, but that in some scenarios the results depend on the way the dimensions shrink to zero. The ratio between the width and the separation determines the detection result. In particular, it is shown that the bunching parameter of bosons is not a well-defined physical property. Moreover, it may suggests that there is a difficulty in quantum measurement theory in the interpretation of coordinate measurement of two particles.

Technical note: Simultaneous carotenoid and vitamin analysis of milk from total mixed ration-fed cows optimized for xanthophyll detection.

PubMed

Stout, M A; Benoist, D M; Drake, M A

2018-06-01

Concentrations of retinol, α-tocopherol, and major carotenoids in dairy products are often determined simultaneously by liquid chromatography. These compounds have different polarity and solubility; thus, extracting them simultaneously can be difficult and inefficient. In milks with low carotenoid concentrations, the xanthophylls lutein and zeaxanthin may not be completely resolved using common extraction techniques. A simplified method was developed to optimize extraction efficiency and the limit of detection and limit of quantification (LoQ) of lutein and zeaxanthin in bovine milk without decreasing sensitivity to other vitamins or carotenoids. The developed method evaluates lutein, zeaxanthin, β-carotene, retinol, and α-tocopherol simultaneously by ultra-high performance liquid chromatography-photodiode array detection. Common saponification temperatures (40-60°C) and concentrations of KOH in water (10-50% KOH wt/vol) were evaluated. Multiple solvents were evaluated for optimal xanthophyll extraction (diethyl ether, dichloromethane, hexane, and tetrahydrofuran) following saponification. The limit of detection and LoQ were defined as 3:1 and 10:1 signal-to-noise ratio, respectively. All experiments were performed in triplicate. The optimal saponification procedure was a concentration of 25% KOH at either 40 or 50°C. Saponified extracts solubilized in solutions containing diethyl ether had greater concentrations of lutein- than hexane- or tetrahydrofuran-based solutions, with peak areas above LoQ values. The solution containing diethyl ether solubilized similar concentrations of retinol, α-tocopherol, and β-carotene when compared with other solutions. The proposed optimized method allows for the simultaneous determination of carotenoids from milk with increased lutein and zeaxanthin sensitivity without sacrificing recovery of retinol, α-tocopherol, and β-carotene. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Measurement of atmospheric ozone by cavity ring-down spectroscopy.

PubMed

Washenfelder, R A; Wagner, N L; Dube, W P; Brown, S S

2011-04-01

Ozone plays a key role in both the Earth's radiative budget and photochemistry. Accurate, robust analytical techniques for measuring its atmospheric abundance are of critical importance. Cavity ring-down spectroscopy has been successfully used for sensitive and accurate measurements of many atmospheric species. However, this technique has not been used for atmospheric measurements of ozone, because the strongest ozone absorption bands occur in the ultraviolet spectral region, where Rayleigh and Mie scattering cause significant cavity losses and dielectric mirror reflectivities are limited. Here, we describe a compact instrument that measures O3 by chemical conversion to NO2 in excess NO, with subsequent detection by cavity ring-down spectroscopy. This method provides a simple, accurate, and high-precision measurement of atmospheric ozone. The instrument consists of two channels. The sum of NO2 and converted O3 (defined as Ox) is measured in the first channel, while NO2 alone is measured in the second channel. NO2 is directly detected in each channel by cavity ring-down spectroscopy with a laser diode light source at 404 nm. The limit of detection for O3 is 26 pptv (2 sigma precision) at 1 s time resolution. The accuracy of the measurement is ±2.2%, with the largest uncertainty being the effective NO2 absorption cross-section. The linear dynamic range of the instrument has been verified from the detection limit to above 200 ppbv (r2>99.99%). The observed precision on signal (2 sigma) with 41 ppbv O3 is 130 pptv in 1 s. Comparison of this instrument to UV absorbance instruments for ambient O3 concentrations shows linear agreement (r2=99.1%) with slope of 1.012±0.002.

Voltammetric Thin-Layer Ionophore-Based Films: Part 2. Semi-Empirical Treatment.

PubMed

Yuan, Dajing; Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

2017-01-03

This work reports on a semiempirical treatment that allows one to rationalize and predict experimental conditions for thin-layer ionophore-based films with cation-exchange capacity read out with cyclic voltammetry. The transition between diffusional mass transport and thin-layer regime is described with a parameter (α), which depends on membrane composition, diffusion coefficient, scan rate, and electrode rotating speed. Once the thin-layer regime is fulfilled (α = 1), the membrane behaves in some analogy to a potentiometric sensor with a second discrimination variable (the applied potential) that allows one to operate such electrodes in a multianalyte detection mode owing to the variable applied ion-transfer potentials. The limit of detection of this regime is defined with a second parameter (β = 2) and is chosen in analogy to the definition of the detection limit for potentiometric sensors provided by the IUPAC. The analytical equations were validated through the simulation of the respective cyclic voltammograms under the same experimental conditions. While simulations of high complexity and better accuracy satisfactorily reproduced the experimental voltammograms during the forward and backward potential sweeps (companion paper 1), the semiempirical treatment here, while less accurate, is of low complexity and allows one to quite easily predict relevant experimental conditions for this emergent methodology.

Desulfurization Activated Phosphorothioate DNAzyme for the Detection of Thallium.

PubMed

Huang, Po-Jung Jimmy; Vazin, Mahsa; Liu, Juewen

2015-10-20

Thallium (Tl) is a highly toxic heavy metal situated between mercury and lead in the periodic table. While its neighbors have been thoroughly studied for DNA-based sensing, little is known about thallium detection. In this work, in vitro selection of RNA-cleaving DNAzymes is carried out using Tl(3+) as the target metal cofactor. Both normal DNA and phosphorothioate (PS)-modified DNA are tested for this purpose. While no Tl(3+)-dependent DNAzymes are obtained, a DNA oligonucleotide containing a single PS-modified RNA nucleotide is found to cleave by ∼7% by Tl(3+) at the RNA position. The remaining 93% are desulfurized. By hybridization of this PS-modified oligonucleotide with the Tm7 DNAzyme, the cleavage yield increases to ∼40% in the presence of Tl(3+) and Er(3+). Tm7 is an Er(3+)-dependent RNA-cleaving DNAzyme. It cleaves only the normal substrate but is completely inactive using the PS-modified substrate. Tl(3+) desulfurizes the PS substrate to the normal substrate to be cleaved by Tm7 and Er(3+). This system is engineered into a catalytic beacon for Tl(3+) with a detection limit of 1.5 nM, which is below its maximal contamination limit defined by the U.S. Environmental Protection Agency (10 nM).

A mind map for managing minimal residual disease in acute myeloid leukemia.

PubMed

Benton, Christopher B; Ravandi, Farhad

2017-11-01

Advances in detecting traces of leukemia that were previously unidentifiable have increasingly led to the incorporation of information about residual disease into clinical decision making for patients with leukemia in both the postinduction and consolidation settings. This review discusses current concepts related to minimal residual disease (MRD), which is defined as submicroscopic disease detected during morphologic complete remission. The focus is on acute myeloid leukemia (AML). Basic methods for detecting MRD include flow cytometry, reverse transcription-polymerase chain reaction, and mutation analysis. Several studies using these assays have demonstrated prognostic implications based on MRD-positive vs MRD-negative status. As our understanding of the biological factors responsible for MRD in AML evolves, residual disease should be evaluated in the context of other prognostic markers. Current therapeutic options for managing MRD in AML are limited, and the clinical implications of a positive MRD test result can be significant. Regarding individual patients, an evidence-based approach must be applied while the institution- and assay-specific differences that currently exist are considered. Challenges associated with MRD assessment, such as the limited standardization of available assays and the paucity of effective agents to eradicate MRD, will need to be overcome before physicians who treat leukemia can use MRD as a tool for clinical management.

Faint source detection in ISOCAM images

NASA Astrophysics Data System (ADS)

Starck, J. L.; Aussel, H.; Elbaz, D.; Fadda, D.; Cesarsky, C.

1999-08-01

We present a tool adapted to the detection of faint mid-infrared sources within ISOCAM mosaics. This tool is based on a wavelet analysis which allows us to discriminate sources from cosmic ray impacts at the very limit of the instrument, four orders of magnitudes below IRAS. It is called PRETI for Pattern REcognition Technique for ISOCAM data, because glitches with transient behaviors are isolated in the wavelet space, i.e. frequency space, where they present peculiar signatures in the form of patterns automatically identified and then reconstructed. We have tested PRETI with Monte-Carlo simulations of fake ISOCAM data. These simulations allowed us to define the fraction of remaining false sources due to cosmic rays, the sensitivity and completeness limits as well as the photometric accuracy as a function of the observation parameters. Although the main scientific applications of this technique have appeared or will appear in separated papers, we present here an application to the ISOCAM-Hubble Deep Field image. This work completes and confirms the results already published (\\cite[Aussel et al. 1999]{starck:aussel99}).

Detecting early functional damage in glaucoma suspect and ocular hypertensive patients with the multifocal VEP technique.

PubMed

Thienprasiddhi, Phamornsak; Greenstein, Vivienne C; Chu, David H; Xu, Li; Liebmann, Jeffrey M; Ritch, Robert; Hood, Donald C

2006-08-01

To determine whether the multifocal visual evoked potential (mfVEP) technique can detect early functional damage in ocular hypertensive (OHT) and glaucoma suspect (GS) patients with normal standard achromatic automated perimetry (SAP) results. Twenty-five GS patients (25 eyes), 25 patients with OHT (25 eyes), and 50 normal controls (50 eyes) were enrolled in this study. All GS, OHT and normal control eyes had normal SAP as defined by a pattern standard deviation and mean deviation within the 95% confidence interval and a glaucoma hemifield test within normal limits on the Humphrey visual field 24-2 program. Eyes with GS had optic disc changes consistent with glaucoma with or without raised intraocular pressure (IOP), and eyes with OHT showed no evidence of glaucomatous optic neuropathy and IOPs >or=22 mm Hg. Monocular mfVEPs were obtained from both eyes of each subject using a pattern-reversal dartboard array with 60 sectors. The entire display had a radius of 22.3 degrees. The mfVEPs, for each eye, were defined as abnormal when either the monocular or interocular probability plot had a cluster of 3 or more contiguous points with P<0.05 and at least 2 of these points with P<0.01. The mfVEP results were abnormal in 4% of the eyes from normal subjects. Abnormal mfVEPs were detected in 20% of the eyes of GS patients and 16% of the eyes of OHT patients. Significantly more mfVEP abnormalities were detected in GS patients than in normal controls. However, there was no significant difference in mfVEP results between OHT patients and normal controls. The mfVEP technique can detect visual field deficits in a minority of eyes with glaucomatous optic disks and normal SAP results.

Esophageal Cancer: Associations With (pN+) Lymph Node Metastases.

PubMed

Rice, Thomas W; Ishwaran, Hemant; Hofstetter, Wayne L; Schipper, Paul H; Kesler, Kenneth A; Law, Simon; Lerut, E M R; Denlinger, Chadrick E; Salo, Jarmo A; Scott, Walter J; Watson, Thomas J; Allen, Mark S; Chen, Long-Qi; Rusch, Valerie W; Cerfolio, Robert J; Luketich, James D; Duranceau, Andre; Darling, Gail E; Pera, Manuel; Apperson-Hansen, Carolyn; Blackstone, Eugene H

2017-01-01

To identify the associations of lymph node metastases (pN+), number of positive nodes, and pN subclassification with cancer, treatment, patient, geographic, and institutional variables, and to recommend extent of lymphadenectomy needed to accurately detect pN+ for esophageal cancer. Limited data and traditional analytic techniques have precluded identifying intricate associations of pN+ with other cancer, treatment, and patient characteristics. Data on 5806 esophagectomy patients from the Worldwide Esophageal Cancer Collaboration were analyzed by Random Forest machine learning techniques. pN+, number of positive nodes, and pN subclassification were associated with increasing depth of cancer invasion (pT), increasing cancer length, decreasing cancer differentiation (G), and more regional lymph nodes resected. Lymphadenectomy necessary to accurately detect pN+ is 60 for shorter, well-differentiated cancers (<2.5 cm) and 20 for longer, poorly differentiated ones. In esophageal cancer, pN+, increasing number of positive nodes, and increasing pN classification are associated with deeper invading, longer, and poorly differentiated cancers. Consequently, if the goal of lymphadenectomy is to accurately define pN+ status of such cancers, few nodes need to be removed. Conversely, superficial, shorter, and well-differentiated cancers require a more extensive lymphadenectomy to accurately define pN+ status.

Framework for behavioral analytics in anomaly identification

NASA Astrophysics Data System (ADS)

Touma, Maroun; Bertino, Elisa; Rivera, Brian; Verma, Dinesh; Calo, Seraphin

2017-05-01

Behavioral Analytics (BA) relies on digital breadcrumbs to build user profiles and create clusters of entities that exhibit a large degree of similarity. The prevailing assumption is that an entity will assimilate the group behavior of the cluster it belongs to. Our understanding of BA and its application in different domains continues to evolve and is a direct result of the growing interest in Machine Learning research. When trying to detect security threats, we use BA techniques to identify anomalies, defined in this paper as deviation from the group behavior. Early research papers in this field reveal a high number of false positives where a security alert is triggered based on deviation from the cluster learned behavior but still within the norm of what the system defines as an acceptable behavior. Further, domain specific security policies tend to be narrow and inadequately represent what an entity can do. Hence, they: a) limit the amount of useful data during the learning phase; and, b) lead to violation of policy during the execution phase. In this paper, we propose a framework for future research on the role of policies and behavior security in a coalition setting with emphasis on anomaly detection and individual's deviation from group activities.

[ProteoСat: a tool for planning of proteomic experiments].

PubMed

Skvortsov, V S; Alekseychuk, N N; Khudyakov, D V; Mikurova, A V; Rybina, A V; Novikova, S E; Tikhonova, O V

2015-01-01

ProteoCat is a computer program has been designed to help researchers in the planning of large-scale proteomic experiments. The central part of this program is the subprogram of hydrolysis simulation that supports 4 proteases (trypsin, lysine C, endoproteinases AspN and GluC). For the peptides obtained after virtual hydrolysis or loaded from data file a number of properties important in mass-spectrometric experiments can be calculated or predicted. The data can be analyzed or filtered to reduce a set of peptides. The program is using new and improved modification of our methods developed to predict pI and probability of peptide detection; pI can also be predicted for a number of popular pKa's scales, proposed by other investigators. The algorithm for prediction of peptide retention time was realized similar to the algorithm used in the program SSRCalc. ProteoCat can estimate the coverage of amino acid sequences of proteins under defined limitation on peptides detection, as well as the possibility of assembly of peptide fragments with user-defined size of "sticky" ends. The program has a graphical user interface, written on JAVA and available at http://www.ibmc.msk.ru/LPCIT/ProteoCat.

Surface regions of illusory images are detected with a slower processing speed than those of luminance-defined images.

PubMed

Mihaylova, Milena; Manahilov, Velitchko

2010-11-24

Research has shown that the processing time for discriminating illusory contours is longer than for real contours. We know, however, little whether the visual processes, associated with detecting regions of illusory surfaces, are also slower as those responsible for detecting luminance-defined images. Using a speed-accuracy trade-off (SAT) procedure, we measured accuracy as a function of processing time for detecting illusory Kanizsa-type and luminance-defined squares embedded in 2D static luminance noise. The data revealed that the illusory images were detected at slower processing speed than the real images, while the points in time, when accuracy departed from chance, were not significantly different for both stimuli. The classification images for detecting illusory and real squares showed that observers employed similar detection strategies using surface regions of the real and illusory squares. The lack of significant differences between the x-intercepts of the SAT functions for illusory and luminance-modulated stimuli suggests that the detection of surface regions of both images could be based on activation of a single mechanism (the dorsal magnocellular visual pathway). The slower speed for detecting illusory images as compared to luminance-defined images could be attributed to slower processes of filling-in of regions of illusory images within the dorsal pathway.

Surface inspection system for carriage parts

NASA Astrophysics Data System (ADS)

Denkena, Berend; Acker, Wolfram

2006-04-01

Quality standards are very high in carriage manufacturing, due to the fact, that the visual quality impression is highly relevant for the purchase decision for the customer. In carriage parts even very small dents can be visible on the varnished and polished surface by observing reflections. The industrial demands are to detect these form errors on the unvarnished part. In order to meet the requirements, a stripe projection system for automatic recognition of waviness and form errors is introduced1. It bases on a modified stripe projection method using a high resolution line scan camera. Particular emphasis is put on achieving a short measuring time and a high resolution in depth, aiming at a reliable automatic recognition of dents and waviness of 10 μm on large curved surfaces of approximately 1 m width. The resulting point cloud needs to be filtered in order to detect dents. Therefore a spatial filtering technique is used. This works well on smoothly curved surfaces, if frequency parameters are well defined. On more complex parts like mudguards the method is restricted by the fact that frequencies near the define dent frequencies occur within the surface as well. To allow analysis of complex parts, the system is currently extended by including 3D CAD models into the process of inspection. For smoothly curved surfaces, the measuring speed of the prototype is mainly limited by the amount of light produced by the stripe projector. For complex surfaces the measuring speed is limited by the time consuming matching process. Currently, the development focuses on the improvement of the measuring speed.

Defining a region of optimization based on engine usage data

DOEpatents

Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

2015-08-04

Methods and systems for engine control optimization are provided. One or more operating conditions of a vehicle engine are detected. A value for each of a plurality of engine control parameters is determined based on the detected one or more operating conditions of the vehicle engine. A range of the most commonly detected operating conditions of the vehicle engine is identified and a region of optimization is defined based on the range of the most commonly detected operating conditions of the vehicle engine. The engine control optimization routine is initiated when the one or more operating conditions of the vehicle engine are within the defined region of optimization.

A simple transformation independent method for outlier definition.

PubMed

Johansen, Martin Berg; Christensen, Peter Astrup

2018-04-10

Definition and elimination of outliers is a key element for medical laboratories establishing or verifying reference intervals (RIs). Especially as inclusion of just a few outlying observations may seriously affect the determination of the reference limits. Many methods have been developed for definition of outliers. Several of these methods are developed for the normal distribution and often data require transformation before outlier elimination. We have developed a non-parametric transformation independent outlier definition. The new method relies on drawing reproducible histograms. This is done by using defined bin sizes above and below the median. The method is compared to the method recommended by CLSI/IFCC, which uses Box-Cox transformation (BCT) and Tukey's fences for outlier definition. The comparison is done on eight simulated distributions and an indirect clinical datasets. The comparison on simulated distributions shows that without outliers added the recommended method in general defines fewer outliers. However, when outliers are added on one side the proposed method often produces better results. With outliers on both sides the methods are equally good. Furthermore, it is found that the presence of outliers affects the BCT, and subsequently affects the determined limits of current recommended methods. This is especially seen in skewed distributions. The proposed outlier definition reproduced current RI limits on clinical data containing outliers. We find our simple transformation independent outlier detection method as good as or better than the currently recommended methods.

A graphene oxide based biosensor for microcystins detection by fluorescence resonance energy transfer.

PubMed

Shi, Yan; Wu, Jiazhen; Sun, Yujing; Zhang, Yue; Wen, Zhiwei; Dai, Haichao; Wang, Hongda; Li, Zhuang

2012-01-01

Water safety is one of the most pervasive problems afflicting people throughout the world. Microcystin, a hepatotoxin produced by cyanobacteria, poses a growing and serious threat of water safety. According to World Health Organization (WHO), the limit of content of microcystin-LR (MC-LR) in drinking water is as low as 1 μg/L; it is thus necessary to explore a sensitive method for the trace detection of microcystins (MCs). Based on the observation of gold nanoparticles (Au NPs) induced graphene oxide (GO) fluorescence quenching, a reliable biosensor was developed here for microcystins detection. MCs could be attached on Au NPs through the interaction with single strand-DNA (ss-DNA) modified on Au NPs, which formed Au-DNA-MCs complexes. These MCs in the complexes could be immunologically recognized by the antibodies adsorbed on GO sheets, as a result, Au NPs were close enough to quench the photoluminescence of GO by the fluorescence resonance energy transfer (FRET). The fluorescence intensity decreased with the increase of MCs as more Au NPs linked onto GO surface. The limit of detection was 0.5 and 0.3 μg/L for microcystin-LR and microcystin-RR (MC-RR), respectively, which satisfies the strictest standard of WHO. Well defined results were also obtained in natural lake water and the specificity experiment. The antibody used here could recognize Adda group, the conservative part of MCs, which allowed the biosensor to detect both single toxin and the total content of MCs existing in the water sample. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Streamlined, PCR-based testing for pfhrp2- and pfhrp3-negative Plasmodium falciparum.

PubMed

Parr, Jonathan B; Anderson, Olivia; Juliano, Jonathan J; Meshnick, Steven R

2018-04-02

Rapid diagnostic tests (RDTs) that detect histidine-rich protein 2 (PfHRP2) are used throughout Africa for the diagnosis of Plasmodium falciparum malaria. However, recent reports indicate that parasites lacking the pfhrp2 and/or histidine-rich protein 3 (pfhrp3) genes, which produce antigens detected by these RDTs, are common in select regions of South America, Asia, and Africa. Proving the absence of a gene is challenging, and multiple PCR assays targeting these genes have been described. A detailed characterization and comparison of published assays is needed to facilitate robust and streamlined testing approaches. Among six pfhrp2 and pfhrp3 PCR assays tested, the lower limit of detection ranged from 0.01 pg/µL to 0.1 ng/µL of P. falciparum 3D7 strain DNA, or approximately 0.4-4000 parasite genomes/µL. By lowering the elongation temperature to 60 °C, a tenfold improvement in the limit of detection and/or darker bands for all exon 1 targets and for the first-round reaction of a single exon 2 target was achieved. Additionally, assays targeting exon 1 of either gene yielded spurious amplification of the paralogous gene. Using these data, an optimized testing algorithm for the detection of pfhrp2- and pfhrp3-negative P. falciparum is proposed. Surveillance of pfhrp2- and pfhrp3-negative P. falciparum requires careful laboratory workflows. PCR-based testing methods coupled with microscopy and/or antigen testing serve as useful tools to support policy development. Standardized approaches to the detection of pfhrp2- and pfhrp3-negative P. falciparum should inform efforts to define the impact of these parasites.

Highly Sensitive and Selective Uranium Detection in Natural Water Systems Using a Luminescent Mesoporous Metal-Organic Framework Equipped with Abundant Lewis Basic Sites: A Combined Batch, X-ray Absorption Spectroscopy, and First Principles Simulation Investigation.

PubMed

Liu, Wei; Dai, Xing; Bai, Zhuanling; Wang, Yanlong; Yang, Zaixing; Zhang, Linjuan; Xu, Lin; Chen, Lanhua; Li, Yuxiang; Gui, Daxiang; Diwu, Juan; Wang, Jianqiang; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

2017-04-04

Uranium is not only a strategic resource for the nuclear industry but also a global contaminant with high toxicity. Although several strategies have been established for detecting uranyl ions in water, searching for new uranium sensor material with great sensitivity, selectivity, and stability remains a challenge. We introduce here a hydrolytically stable mesoporous terbium(III)-based MOF material compound 1, whose channels are as large as 27 Å × 23 Å and are equipped with abundant exposed Lewis basic sites, the luminescence intensity of which can be efficiently and selectively quenched by uranyl ions. The detection limit in deionized water reaches 0.9 μg/L, far below the maximum contamination standard of 30 μg/L in drinking water defined by the United States Environmental Protection Agency, making compound 1 currently the only MOF material that can achieve this goal. More importantly, this material exhibits great capability in detecting uranyl ions in natural water systems such as lake water and seawater with pH being adjusted to 4, where huge excesses of competing ions are present. The uranyl detection limits in Dushu Lake water and in seawater were calculated to be 14.0 and 3.5 μg/L, respectively. This great detection capability originates from the selective binding of uranyl ions onto the Lewis basic sites of the MOF material, as demonstrated by synchrotron radiation extended X-ray adsorption fine structure, X-ray adsorption near edge structure, and first principles calculations, further leading to an effective energy transfer between the uranyl ions and the MOF skeleton.

EARLY SCIENCE WITH THE KOREAN VLBI NETWORK: THE QCAL-1 43 GHz CALIBRATOR SURVEY

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

Petrov, Leonid; Lee, Sang-Sung; Kim, Jongsoo

2012-11-01

This paper presents the catalog of correlated flux densities in three ranges of baseline projection lengths of 637 sources from a 43 GHz (Q band) survey observed with the Korean VLBI Network. Of them, 14 objects used as calibrators were previously observed, but 623 sources have not been observed before in the Q band with very long baseline interferometry (VLBI). The goal of this work in the early science phase of the new VLBI array is twofold: to evaluate the performance of the new instrument that operates in a frequency range of 22-129 GHz and to build a list ofmore » objects that can be used as targets and as calibrators. We have observed the list of 799 target sources with declinations down to -40 Degree-Sign . Among them, 724 were observed before with VLBI at 22 GHz and had correlated flux densities greater than 200 mJy. The overall detection rate is 78%. The detection limit, defined as the minimum flux density for a source to be detected with 90% probability in a single observation, was in the range of 115-180 mJy depending on declination. However, some sources as weak as 70 mJy have been detected. Of 623 detected sources, 33 objects are detected for the first time in VLBI mode. We determined their coordinates with a median formal uncertainty of 20 mas. The results of this work set the basis for future efforts to build the complete flux-limited sample of extragalactic sources at frequencies of 22 GHz and higher at 3/4 of the celestial sphere.« less

Outcome by Exercise Echocardiography in Patients with Low Pretest Probability of Coronary Artery Disease.

PubMed

Peteiro, Jesus; Bouzas-Mosquera, Alberto; Broullon, Javier; Sanchez-Fernandez, Gabriel; Perez-Cebey, Lucia; Yañez, Juan; Martinez, Dolores; Vazquez-Rodriguez, Jose M

2016-08-01

Recommendations for testing in patients with low pretest probability of coronary artery disease differ in guidelines from no testing at all to different tests. The aim of this study was to assess the value of exercise echocardiography (ExE) to define outcome in this population. A retrospective analysis was conducted of 1,436 patients with low pretest probability of coronary artery disease (<15%) who underwent initial ExE. Overall mortality, major adverse cardiac events (MACEs), defined as cardiac death or nonfatal myocardial infarction, and revascularization during follow-up, were assessed. Ischemia (development of new wall motion abnormalities with exercise) and fixed wall motion abnormalities were measured. The mean age was 50 ± 12 years. Resting wall motion abnormalities were seen in 13 patients (0.9%) and ischemia in 108 (7.5%). During follow-up, 38 patients died, 10 of cardiac death (annualized death rate, 0.39%); 20 patients had MACEs (annualized MACE rate, 0.21%); and 48 patients (29 with ischemia) underwent revascularization (annualized revascularization rate, 0.51%). The number and percentage of MACEs in the abnormal and normal ExE groups were similar (two [1.7%] vs 18 [1.4%], P = .70), as was the annualized MACE rate (0.31% vs 0.21%, P = .50). Peak left ventricular ejection fraction exhibited a nonsignificant trend for predicting MACEs (P = .11). The number of studies needed to detect an abnormal finding was 12.6 and to detect a patient with extensive ischemia was 26.1. ExE offers limited prognostic information in patients with low pretest probability of coronary artery disease. The small number of abnormal findings on ExE and low event rates and the large number of studies needed to detect an abnormal finding limit further the value of imaging in this population. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Bimetallic 3D nanostar dimers in ring cavities: recyclable and robust surface-enhanced Raman scattering substrates for signal detection from few molecules.

PubMed

Gopalakrishnan, Anisha; Chirumamilla, Manohar; De Angelis, Francesco; Toma, Andrea; Zaccaria, Remo Proietti; Krahne, Roman

2014-08-26

Top-down fabrication of electron-beam lithography (EBL)-defined metallic nanostructures is a successful route to obtain extremely high electromagnetic field enhancement via plasmonic effects in well-defined regions. To this aim, various geometries have been introduced such as disks, triangles, dimers, rings, self-similar lenses, and more. In particular, metallic dimers are highly efficient for surface-enhanced Raman spectroscopy (SERS), and their decoupling from the substrate in a three-dimensional design has proven to further improve their performance. However, the large fabrication time and cost has hindered EBL-defined structures from playing a role in practical applications. Here we present three-dimensional nanostar dimer devices that can be recycled via maskless metal etching and deposition processes, due to conservation of the nanostructure pattern in the 3D geometry of the underlying Si substrate. Furthermore, our 3D-nanostar-dimer-in-ring structures (3D-NSDiRs) incorporate several advantageous aspects for SERS by enhancing the performance of plasmonic dimers via an external ring cavity, by efficient decoupling from the substrate through an elevated 3D design, and by bimetallic AuAg layers that exploit the increased performance of Ag while maintaining the biocompatibility of Au. We demonstrate SERS detection on rhodamine and adenine at extremely low density up to the limit of few molecules and analyze the field enhancement of the 3D-NSDiRs with respect to the exciting wavelength and metal composition.

Perfluorocarbons enhance a T2*-based MRI technique for identifying the penumbra in a rat model of acute ischemic stroke

PubMed Central

Deuchar, Graeme A; Brennan, David; Griffiths, Hugh; Macrae, I  Mhairi; Santosh, Celestine

2013-01-01

Accurate imaging of ischemic penumbra is crucial for improving the management of acute stroke patients. T2* magnetic resonance imaging (MRI) combined with a T2*oxygen challenge (T2*OC) is being developed to detect penumbra based on changes in blood deoxyhemoglobin. Using 100% O2, T2*OC-defined penumbra exhibits ongoing glucose metabolism and tissue recovery on reperfusion. However, potential limitations in translating this technique include a sinus artefact in human scans with delivery of 100% OC and relatively small signal changes. Here we investigate whether an oxygen-carrying perfluorocarbon (PFC) emulsion can enhance the sensitivity of the technique, enabling penumbra detection with lower levels of inspired oxygen. Stroke was induced in male Sprague-Dawley rats (n=17) with ischemic injury and perfusion deficit determined by diffusion and perfusion MRI, respectively. T2* signal change was measured in regions of interest (ROIs) located within ischemic core, T2*OC-defined penumbra and equivalent contralateral areas during 40% O2±prior PFC injection. Region of interest analyses between groups showed that PFC significantly enhanced the T2* response to 40% O2 in T2*-defined penumbra (mean increase of 10.6±2.3% compared to 5.6±1.5% with 40% O2, P<0.001). This enhancement was specific to the penumbra ROI. Perfluorocarbon emulsions therefore enhances the translational potential of the T2*OC technique for identifying penumbra in acute stroke patients. PMID:23801243

Cue combination in a combined feature contrast detection and figure identification task.

PubMed

Meinhardt, Günter; Persike, Malte; Mesenholl, Björn; Hagemann, Cordula

2006-11-01

Target figures defined by feature contrast in spatial frequency, orientation or both cues had to be detected in Gabor random fields and their shape had to be identified in a dual task paradigm. Performance improved with increasing feature contrast and was strongly correlated among both tasks. Subjects performed significantly better with combined cues than with single cues. The improvement due to cue summation was stronger than predicted by the assumption of independent feature specific mechanisms, and increased with the performance level achieved with single cues until it was limited by ceiling effects. Further, cue summation was also strongly correlated among tasks: when there was benefit due to the additional cue in feature contrast detection, there was also benefit in figure identification. For the same performance level achieved with single cues, cue summation was generally larger in figure identification than in feature contrast detection, indicating more benefit when processes of shape and surface formation are involved. Our results suggest that cue combination improves spatial form completion and figure-ground segregation in noisy environments, and therefore leads to more stable object vision.

Detecting spatial regimes in ecosystems

USGS Publications Warehouse

Sundstrom, Shana M.; Eason, Tarsha; Nelson, R. John; Angeler, David G.; Barichievy, Chris; Garmestani, Ahjond S.; Graham, Nicholas A.J.; Granholm, Dean; Gunderson, Lance; Knutson, Melinda; Nash, Kirsty L.; Spanbauer, Trisha; Stow, Craig A.; Allen, Craig R.

2017-01-01

Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological potential (i.e. potential vegetation), and often fail to account for ongoing changes due to stressors such as land use change and climate change and their effects on plant and animal communities. We use Fisher information, an information theory-based method, on both terrestrial and aquatic animal data (U.S. Breeding Bird Survey and marine zooplankton) to identify ecological boundaries, and compare our results to traditional early warning indicators, conventional ecoregion maps and multivariate analyses such as nMDS and cluster analysis. We successfully detected spatial regimes and transitions in both terrestrial and aquatic systems using Fisher information. Furthermore, Fisher information provided explicit spatial information about community change that is absent from other multivariate approaches. Our results suggest that defining spatial regimes based on animal communities may better reflect ecological reality than do traditional ecoregion maps, especially in our current era of rapid and unpredictable ecological change.

A highly selective turn-on fluorescent probe for Al3+ in aqueous solution based on quinoline Schiff-base

NASA Astrophysics Data System (ADS)

Huang, Peng-Cheng; Fang, Hao; Xiong, Jing-Jing; Wu, Fang-Ying

2017-06-01

A new Al3+-specific fluorescent probe NQ was designed and synthesized from 2-hydroxy-1-naphthaldehyde and 2-aminoquinoline. Upon the addition of Al3+, the fluorescent intensity of NQ was significantly enhanced compared with other examined metal ions in aqueous solution. The result of a Job’s plot indicated the formation of a 1:1 complex between the probe and Al3+, and the possible binding mode of the system between NQ and Al3+ was clarified by IR analysis and 1H NMR titration. Moreover, other metal ions examined had little effect on the detection of Al3+. The detection limit of NQ for Al3+ detection was 1.98 μM, which is lower than the level (7.4 μM) in drinking water defined by the World Health Organization. In addition, the fluorescent probe NQ could be recyclable simply through treatment with a proper reagent such as F-, and could also be used for the detection of Al3+ in real samples.

An investigation of the well-water quality: immunosensor for pathogenic Pseudomonas aeruginosa detection based on antibody-modified poly(pyrrole-3 carboxylic acid) screen-printed carbon electrode.

PubMed

Bekir, Karima; Bousimma, Feriel; Barhoumi, Houcine; Fedhila, Kais; Maaref, Abderrazak; Bakhrouf, Amina; Ben Ouada, Hafedh; Namour, Philippe; Jaffrezic-Renault, Nicole; Ben Mansour, Hedi

2015-12-01

In this report, we describe a new immunosensor designed for the detection and the quantification of Pseudomonas aeruginosa bacteria in water. The developed biosensing system was based on the immobilization of purified polyclonal anti P. aeruginosa antibodies on electropolymerized poly(pyrrole-3-carboxylic acid)/glassy carbon electrode. The building of the immunosensor step by step was evaluated by electrochemical measurements such as cyclic voltammetry (CV) and impedance spectroscopy (EIS). The electrochemical signature of the immunosensor was established by the change of the charge transfer resistance when the bacteria suspended in solution became attached to the immobilized antibodies. As a result, stable and high sensitive impedimetric immunosensor was obtained with a sensitivity of 0.19 kΩ/decade defined in the linear range from 10(1) to 10(7) CFU/mL of cellular concentrations. A low detection limit was obtained for the P. aeruginosa bacteria and a high selectivity when other bacteria were occasioned as well as Escherichia coli. The developed immunosensor was applied in detecting pathogenic P. aeruginosa in well-water.

Olfaction in a viscous environment: the "color" of sexual smells in Temora longicornis

NASA Astrophysics Data System (ADS)

Hinow, Peter; Strickler, J. Rudi; Yen, Jeannette

2017-06-01

We investigate chemical aspects of mating in the marine copepod Temora longicornis (Copepoda, Calanoidea). Our emphasis is the female pheromone signaling in form of well-defined trails for males to follow, observed in Doall et al. (Phil Trans R Soc Lond B 353:681-689, 1998). The viscous environment and the properties of the odorants play important roles as the spread of the pheromone trail limits the time during which it is useful for tracing. A key observation from our earlier work is the ability of a searching male to detect the direction of the female and to correct its swimming direction if necessary. We propose a simple mathematical model for the spread of a pheromone from a moving source and carry out numerical simulations of two possible detection mechanisms. We find that a searching agent that is capable to detect a ratio outperforms a searcher that depends on the gradient of a single compound. This suggests that copepod sex pheromones consist of blends of chemical compounds, and that a ratio detection mechanism similar to that in airborne insects is at work.

Consistent detection of global predicates

NASA Technical Reports Server (NTRS)

Cooper, Robert; Marzullo, Keith

1991-01-01

A fundamental problem in debugging and monitoring is detecting whether the state of a system satisfies some predicate. If the system is distributed, then the resulting uncertainty in the state of the system makes such detection, in general, ill-defined. Three algorithms are presented for detecting global predicates in a well-defined way. These algorithms do so by interpreting predicates with respect to the communication that has occurred in the system.

New method for analyzing dark matter direct detection data

NASA Astrophysics Data System (ADS)

Davis, Jonathan H.; Enßlin, Torsten; BÅ`hm, Céline

2014-02-01

The experimental situation of dark matter direct detection has reached an exciting crossroads, with potential hints of a discovery of dark matter (DM) from the CDMS, CoGeNT, CRESST-II and DAMA experiments in tension with null results from xenon-based experiments such as XENON100 and LUX. Given the present controversial experimental status, it is important that the analytical method used to search for DM in direct detection experiments is both robust and flexible enough to deal with data for which the distinction between signal and background points is difficult, and hence where the choice between setting a limit or defining a discovery region is debatable. In this article we propose a novel (Bayesian) analytical method, which can be applied to all direct detection experiments and which extracts the maximum amount of information from the data. We apply our method to the XENON100 experiment data as a worked example, and show that firstly our exclusion limit at 90% confidence is in agreement with their own for the 225 live days data, but is several times stronger for the 100 live days data. Secondly we find that, due to the two points at low values of S1 and S2 in the 225 days data set, our analysis points to either weak consistency with low-mass dark matter or the possible presence of an unknown background. Given the null result from LUX, the latter scenario seems the more plausible.

Batch Statistical Process Monitoring Approach to a Cocrystallization Process.

PubMed

Sarraguça, Mafalda C; Ribeiro, Paulo R S; Dos Santos, Adenilson O; Lopes, João A

2015-12-01

Cocrystals are defined as crystalline structures composed of two or more compounds that are solid at room temperature held together by noncovalent bonds. Their main advantages are the increase of solubility, bioavailability, permeability, stability, and at the same time retaining active pharmaceutical ingredient bioactivity. The cocrystallization between furosemide and nicotinamide by solvent evaporation was monitored on-line using near-infrared spectroscopy (NIRS) as a process analytical technology tool. The near-infrared spectra were analyzed using principal component analysis. Batch statistical process monitoring was used to create control charts to perceive the process trajectory and define control limits. Normal and non-normal operating condition batches were performed and monitored with NIRS. The use of NIRS associated with batch statistical process models allowed the detection of abnormal variations in critical process parameters, like the amount of solvent or amount of initial components present in the cocrystallization. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Differential Item Functioning Detection across Two Methods of Defining Group Comparisons: Pairwise and Composite Group Comparisons

ERIC Educational Resources Information Center

Sari, Halil Ibrahim; Huggins, Anne Corinne

2015-01-01

This study compares two methods of defining groups for the detection of differential item functioning (DIF): (a) pairwise comparisons and (b) composite group comparisons. We aim to emphasize and empirically support the notion that the choice of pairwise versus composite group definitions in DIF is a reflection of how one defines fairness in DIF…

Lake Chapala change detection using time series

NASA Astrophysics Data System (ADS)

López-Caloca, Alejandra; Tapia-Silva, Felipe-Omar; Escalante-Ramírez, Boris

2008-10-01

The Lake Chapala is the largest natural lake in Mexico. It presents a hydrological imbalance problem caused by diminishing intakes from the Lerma River, pollution from said volumes, native vegetation and solid waste. This article presents a study that allows us to determine with high precision the extent of the affectation in both extension and volume reduction of the Lake Chapala in the period going from 1990 to 2007. Through satellite images this above-mentioned period was monitored. Image segmentation was achieved through a Markov Random Field model, extending the application towards edge detection. This allows adequately defining the lake's limits as well as determining new zones within the lake, both changes pertaining the Lake Chapala. Detected changes are related to a hydrological balance study based on measuring variables such as storage volumes, evapotranspiration and water balance. Results show that the changes in the Lake Chapala establish frail conditions which pose a future risk situation. Rehabilitation of the lake requires a hydrologic balance in its banks and aquifers.

An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

NASA Technical Reports Server (NTRS)

Ross, H. Richard

1993-01-01

A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators.

PubMed

Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François

2017-07-27

Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila . These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision.

Counting polymers moving through a single ion channel

NASA Astrophysics Data System (ADS)

Bezrukov, Sergey M.; Vodyanoy, Igor; Parsegian, V. Adrian

1994-07-01

THE change in conductance of a small electrolyte-filled capillary owing to the passage of sub-micrometre-sized particles has long been used for particle counting and sizing. A commercial device for such measurements, the Coulter counter, is able to detect particles of sizes down to several tenths of a micrometre1-3. Nuclepore technology (in which pores are etched particle tracks) has extended the lower limit of size detection to 60-nm particles by using a capillary of diameter 0.45 μm (ref. 4). Here we show that natural channel-forming peptides incorporated into a bilayer lipid membrane can be used to detect the passage of single molecules with gyration radii as small as 5-15 Å. From our experiments with alamethicin pores we infer both the average number and the diffusion coefficients of poly(ethylene glycol) molecules in the pore. Our approach provides a means of observing the statistics and mechanics of flexible polymers moving within the confines of precisely defined single-molecule structures.

Thermographic imaging for high-temperature composite materials: A defect detection study

NASA Technical Reports Server (NTRS)

Roth, Don J.; Bodis, James R.; Bishop, Chip

1995-01-01

The ability of a thermographic imaging technique for detecting flat-bottom hole defects of various diameters and depths was evaluated in four composite systems (two types of ceramic matrix composites, one metal matrix composite, and one polymer matrix composite) of interest as high-temperature structural materials. The holes ranged from 1 to 13 mm in diameter and 0.1 to 2.5 mm in depth in samples approximately 2-3 mm thick. The thermographic imaging system utilized a scanning mirror optical system and infrared (IR) focusing lens in conjunction with a mercury cadmium telluride infrared detector element to obtain high resolution infrared images. High intensity flash lamps located on the same side as the infrared camera were used to heat the samples. After heating, up to 30 images were sequentially acquired at 70-150 msec intervals. Limits of detectability based on depth and diameter of the flat-bottom holes were defined for each composite material. Ultrasonic and radiographic images of the samples were obtained and compared with the thermographic images.

Low-dose electron energy-loss spectroscopy using electron counting direct detectors.

PubMed

Maigné, Alan; Wolf, Matthias

2018-03-01

Since the development of parallel electron energy loss spectroscopy (EELS), charge-coupled devices (CCDs) have been the default detectors for EELS. With the recent development of electron-counting direct-detection cameras, micrographs can be acquired under very low electron doses at significantly improved signal-to-noise ratio. In spectroscopy, in particular in combination with a monochromator, the signal can be extremely weak and the detection limit is principally defined by noise introduced by the detector. Here we report the use of an electron-counting direct-detection camera for EEL spectroscopy. We studied the oxygen K edge of amorphous ice and obtained a signal noise ratio up to 10 times higher than with a conventional CCD.We report the application of electron counting to record time-resolved EEL spectra of a biological protein embedded in amorphous ice, revealing chemical changes observed in situ while exposed by the electron beam. A change in the fine structure of nitrogen K and the carbon K edges were recorded during irradiation. A concentration of 3 at% nitrogen was detected with a total electron dose of only 1.7 e-/Å2, extending the boundaries of EELS signal detection at low electron doses.

Near-infrared photoluminescence biosensing platform with gold nanorods-over-gallium arsenide nanohorn array.

PubMed

Zhang, Yiming; Jiang, Tao; Tang, Longhua

2017-11-15

The near-infrared (NIR) optical detection of biomolecules with high sensitivity and reliability have been expected, however, it is still a challenge. In this work, we present a gold nanorods (AuNRs)-over-gallium arsenide nanohorn-like array (GaAs NHA) system that can be used for the ultrasensitive and specific NIR photoluminescence (PL) detection of DNA and proteins. The fabrication of GaAs NHA involved the technique of colloidal lithography and inductively coupled plasma dry etching, yielding large-area and well-defined nanostructural array, and exhibiting an improved PL emission compared to the planar GaAs substrate. Importantly, we found that the DNA-bridged AuNRs attachment on NHA could further improve the PL intensity from GaAs, and thereby provide the basis for the NIR optical sensing of biological analytes. We demonstrated that DNA and thrombin could be sensitively and specifically detected, with the detection limit of 1 pM for target DNA and 10 pM for thrombin. Such ultrasensitive NIR optical platform can extend to the detection of other biomarkers and is promising for clinical diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Acute respiratory distress syndrome 40 years later: time to revisit its definition.

PubMed

Phua, Jason; Stewart, Thomas E; Ferguson, Niall D

2008-10-01

Acute respiratory distress syndrome is a common disorder associated with significant mortality and morbidity. The aim of this article is to critically evaluate the definition of acute respiratory distress syndrome and examine the impact the definition has on clinical practice and research. Articles from a MEDLINE search (1950 to August 2007) using the Medical Subject Heading respiratory distress syndrome, adult, diagnosis, limited to the English language and human subjects, their relevant bibliographies, and personal collections, were reviewed. The definition of acute respiratory distress syndrome is important to researchers, clinicians, and administrators alike. It has evolved significantly over the last 40 years, culminating in the American-European Consensus Conference definition, which was published in 1994. Although the American-European Consensus Conference definition is widely used, it has some important limitations that may impact on the conduct of clinical research, on resource allocation, and ultimately on the bedside management of such patients. These limitations stem partially from the fact that as defined, acute respiratory distress syndrome is a heterogeneous entity and also involve the reliability and validity of the criteria used in the definition. This article critically evaluates the American-European Consensus Conference definition and its limitations. Importantly, it highlights how these limitations may contribute to clinical trials that have failed to detect a potential true treatment effect. Finally, recommendations are made that could be considered in future definition modifications with an emphasis on the significance of accurately identifying the target population in future trials and subsequently in clinical care. How acute respiratory distress syndrome is defined has a significant impact on the results of randomized, controlled trials and epidemiologic studies. Changes to the current American-European Consensus Conference definition are likely to have an important role in advancing the understanding and management of acute respiratory distress syndrome.

Cryogenic colocalization microscopy for nanometer-distance measurements.

PubMed

Weisenburger, Siegfried; Jing, Bo; Hänni, Dominik; Reymond, Luc; Schuler, Benjamin; Renn, Alois; Sandoghdar, Vahid

2014-03-17

The main limiting factor in spatial resolution of localization microscopy is the number of detected photons. Recently we showed that cryogenic measurements improve the photostability of fluorophores, giving access to Angstrom precision in localization of single molecules. Here, we extend this method to colocalize two fluorophores attached to well-defined positions of a double-stranded DNA. By measuring the separations of the fluorophore pairs prepared at different design positions, we verify the feasibility of cryogenic distance measurement with sub-nanometer accuracy. We discuss the important challenges of our method as well as its potential for further improvement and various applications.

Update on Chemical Analysis of Recovered Hydrazine Family Fuels for Recycling

NASA Technical Reports Server (NTRS)

Davis, C. L.

1997-01-01

The National Aeronautics and Space Administration, Kennedy Space Center, has developed a program to re-use and/or recycle hypergolic propellants recovered from propellant systems. As part of this effort, new techniques were developed to analyze recovered propellants. At the 1996 PDCS, the paper 'Chemical Analysis of Recovered Hydrazine Family Fuels For Recycling' presented analytical techniques used in accordance with KSC specifications which define what recovered propellants are acceptable for recycling. This paper is a follow up to the 1996 paper. Lower detection limits and response linearity were examined for two gas chromatograph methods.

Transmissive Nanohole Arrays for Massively-Parallel Optical Biosensing

PubMed Central

2015-01-01

A high-throughput optical biosensing technique is proposed and demonstrated. This hybrid technique combines optical transmission of nanoholes with colorimetric silver staining. The size and spacing of the nanoholes are chosen so that individual nanoholes can be independently resolved in massive parallel using an ordinary transmission optical microscope, and, in place of determining a spectral shift, the brightness of each nanohole is recorded to greatly simplify the readout. Each nanohole then acts as an independent sensor, and the blocking of nanohole optical transmission by enzymatic silver staining defines the specific detection of a biological agent. Nearly 10000 nanoholes can be simultaneously monitored under the field of view of a typical microscope. As an initial proof of concept, biotinylated lysozyme (biotin-HEL) was used as a model analyte, giving a detection limit as low as 0.1 ng/mL. PMID:25530982

Conductive polymer nanowire gas sensor fabricated by nanoscale soft lithography

NASA Astrophysics Data System (ADS)

Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

2017-12-01

Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation of gas sensors. However, the large-scale fabrication of nanowires is still challenging, which restricts the commercialization of such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive gas sensors by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate, which facilitates device integration. The nanowire chemiresistive gas sensor is demonstrated for NH3 and NO2 detection at room temperature and shows a limit of detection at ppb level, which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with the conventional lithography technique. In comparison with PEDOT:PSS thin-film gas sensors, the nanowire gas sensor exhibits higher sensitivity and a much faster response to gas molecules.

Conductive polymer nanowire gas sensor fabricated by nanoscale soft lithography.

PubMed

Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

2017-12-01

Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation of gas sensors. However, the large-scale fabrication of nanowires is still challenging, which restricts the commercialization of such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive gas sensors by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate, which facilitates device integration. The nanowire chemiresistive gas sensor is demonstrated for NH 3 and NO 2 detection at room temperature and shows a limit of detection at ppb level, which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with the conventional lithography technique. In comparison with PEDOT:PSS thin-film gas sensors, the nanowire gas sensor exhibits higher sensitivity and a much faster response to gas molecules.

Detection of coliform bacteria and Escherichia coli by multiplex polymerase chain reaction: comparison with defined substrate and plating methods for water quality monitoring.

PubMed Central

Bej, A K; McCarty, S C; Atlas, R M

1991-01-01

Multiplex polymerase chain reaction (PCR) and gene probe detection of target lacZ and uidA genes were used to detect total coliform bacteria and Escherichia coli, respectively, for determining water quality. In tests of environmental water samples, the lacZ PCR method gave results statistically equivalent to those of the plate count and defined substrate methods accepted by the U.S. Environmental Protection Agency for water quality monitoring and the uidA PCR method was more sensitive than 4-methylumbelliferyl-beta-D-glucuronide-based defined substrate tests for specific detection of E. coli. Images PMID:1768116

Association of incidental emphysema with annual lung function decline and future development of airflow limitation

PubMed Central

Koo, Hyeon-Kyoung; Jin, Kwang Nam; Kim, Deog Kyeom; Chung, Hee Soon; Lee, Chang-Hoon

2016-01-01

Objectives Emphysema is one of the prognostic factors for rapid lung function decline in patients with COPD, but the impact of incidentally detected emphysema on population without spirometric abnormalities has not been evaluated. This study aimed to determine whether emphysema detected upon computed tomography (CT) screening would accelerate the rate of lung function decline and influence the possibility of future development of airflow limitation in a population without spirometric abnormalities. Materials and methods Subjects who participated in a routine screening for health checkup and follow-up pulmonary function tests for at least 3 years between 2004 and 2010 were retrospectively enrolled. The percentage of low-attenuation area below −950 Hounsfield units (%LAA−950) was calculated automatically. A calculated value of %LAA−950 that exceeded 10% was defined as emphysema. Adjusted annual lung function decline was analyzed using random-slope, random-intercept mixed linear regression models. Results A total of 628 healthy subjects within the normal range of spriometric values were included. Multivariable analysis showed that the emphysema group exhibited a faster decline in forced vital capacity (−33.9 versus −18.8 mL/year; P=0.02). Emphysema was not associated with the development of airflow limitation during follow-up. Conclusion Incidental emphysema quantified using CT scan was significantly associated with a more rapid decline in forced vital capacity in the population with normative spirometric values. However, an association between emphysema and future development of airflow limitation was not observed. PMID:26893550

Evaluation of exposure-response relationships for health effects of microbial bioaerosols - A systematic review.

PubMed

Walser, Sandra M; Gerstner, Doris G; Brenner, Bernhard; Bünger, Jürgen; Eikmann, Thomas; Janssen, Barbara; Kolb, Stefanie; Kolk, Annette; Nowak, Dennis; Raulf, Monika; Sagunski, Helmut; Sedlmaier, Nadja; Suchenwirth, Roland; Wiesmüller, Gerhard; Wollin, Klaus-Michael; Tesseraux, Irene; Herr, Caroline E W

2015-10-01

Studies suggest adverse health effects following exposure to bioaerosols in the environment and in particular at workplaces. However, there is still a lack of health-related exposure limits based on toxicological or epidemiological studies from environmental health or from the working environment. The aim of this study was to derive health-based exposure limits for bioaerosols that can protect the general population as group "at risk" via environmental exposure using analysis of peer-reviewed studies related to occupational medicine, indoor air and environmental health. The derivation of exposure limits should be conducted by the members of a bioaerosol expert panel according to established toxicological criteria. A systematic review was performed in Medline (PubMed) including studies containing both data on exposure measurements and observed health outcomes. In addition, literature recommended by the experts was considered. A comprehensive search strategy was generated and resulted in a total of n=1569 studies in combination with the literature recommendations. Subsequently, abstracts were screened using defined exclusion criteria yielding a final number of n=44 studies. A standardized extraction sheet was used to combine data on health effects and exposure to different bioaerosols. After full-text screening and extraction according to the defined exclusion criteria n=20 studies were selected all related to occupational exposures comprising the working areas wood processing, farming, waste processing and others. These studies were analyzed in collaboration with the bioaerosol expert network in terms of suitability for derivation of health-related exposure limits. The bioaerosol expert network concluded that none of the analyzed studies provided suitable dose-response relationships for derivation of exposure limits. The main reasons were: (1) lack of studies with valid dose-response data; (2) diversity of employed measuring methods for microorganisms and bioaerosol-emitting facilities; (3) heterogeneity of health effects; (4) insufficient exposure assessment. However, several indicator parameters and exposure concentrations could be identified for different bioaerosol-emitting facilities. Nevertheless, health-related exposure limits are urgently needed especially in approval procedures of facilities like composting plants or livestock farms emitting bioaerosols in the neighbourhood of residents. In the regulatory toxicology framework, it is common to use animal experimental studies for derivation of general exposure limits if appropriate environmental epidemiological studies on harmful substances are lacking. This might be another possibility to obtain health-related exposure limits for specific bioaerosol parameters. Furthermore, we recommend to use suitable measurable outcome parameters related to bioaerosols; to measure bioaerosols according to a protocol representative for exposure pattern and duration at the particular work place; to develop standardized detection methods for indicator parameters; to combine different detection methods to compensate for the limitations of each method; to apply new analysis methods to identify the real risk potential. Copyright © 2015 Elsevier GmbH. All rights reserved.

Diagnostic performance of body mass index using the Western Pacific Regional Office of World Health Organization reference standards for body fat percentage.

PubMed

Yoon, Jong Lull; Cho, Jung Jin; Park, Kyung Mi; Noh, Hye Mi; Park, Yong Soon

2015-02-01

Associations between body mass index (BMI), body fat percentage (BF%), and health risks differ between Asian and European populations. BMI is commonly used to diagnose obesity; however, its accuracy in detecting adiposity in Koreans is unknown. The present cross-sectional study aimed at assessing the accuracy of BMI in determining BF%-defined obesity in 6,017 subjects (age 20-69 yr, 43.6% men) from the 2009 Korean National Health and Nutrition Examination Survey. We assessed the diagnostic performance of BMI using the Western Pacific Regional Office of World Health Organization reference standard for BF%-defined obesity by sex and age and identified the optimal BMI cut-off for BF%-defined obesity using receiver operating characteristic curve analysis. BMI-defined obesity (≥25 kg/m(2)) was observed in 38.7% of men and 28.1% of women, with a high specificity (89%, men; 84%, women) but poor sensitivity (56%, men; 72% women) for BF%-defined obesity (25.2%, men; 31.1%, women). The optimal BMI cut-off (24.2 kg/m(2)) had 78% sensitivity and 71% specificity. BMI demonstrated limited diagnostic accuracy for adiposity in Korea. There was a -1.3 kg/m(2) difference in optimal BMI cut-offs between Korea and America, smaller than the 5-unit difference between the Western Pacific Regional Office and global World Health Organization obesity criteria.

Stationary Random Metrics on Hierarchical Graphs Via {(min,+)}-type Recursive Distributional Equations

NASA Astrophysics Data System (ADS)

Khristoforov, Mikhail; Kleptsyn, Victor; Triestino, Michele

2016-07-01

This paper is inspired by the problem of understanding in a mathematical sense the Liouville quantum gravity on surfaces. Here we show how to define a stationary random metric on self-similar spaces which are the limit of nice finite graphs: these are the so-called hierarchical graphs. They possess a well-defined level structure and any level is built using a simple recursion. Stopping the construction at any finite level, we have a discrete random metric space when we set the edges to have random length (using a multiplicative cascade with fixed law {m}). We introduce a tool, the cut-off process, by means of which one finds that renormalizing the sequence of metrics by an exponential factor, they converge in law to a non-trivial metric on the limit space. Such limit law is stationary, in the sense that glueing together a certain number of copies of the random limit space, according to the combinatorics of the brick graph, the obtained random metric has the same law when rescaled by a random factor of law {m} . In other words, the stationary random metric is the solution of a distributional equation. When the measure m has continuous positive density on {mathbf{R}+}, the stationary law is unique up to rescaling and any other distribution tends to a rescaled stationary law under the iterations of the hierarchical transformation. We also investigate topological and geometric properties of the random space when m is log-normal, detecting a phase transition influenced by the branching random walk associated to the multiplicative cascade.

In chronic myeloid leukemia patients on second-line tyrosine kinase inhibitor therapy, deep sequencing of BCR-ABL1 at the time of warning may allow sensitive detection of emerging drug-resistant mutants.

PubMed

Soverini, Simona; De Benedittis, Caterina; Castagnetti, Fausto; Gugliotta, Gabriele; Mancini, Manuela; Bavaro, Luana; Machova Polakova, Katerina; Linhartova, Jana; Iurlo, Alessandra; Russo, Domenico; Pane, Fabrizio; Saglio, Giuseppe; Rosti, Gianantonio; Cavo, Michele; Baccarani, Michele; Martinelli, Giovanni

2016-08-02

Imatinib-resistant chronic myeloid leukemia (CML) patients receiving second-line tyrosine kinase inhibitor (TKI) therapy with dasatinib or nilotinib have a higher risk of disease relapse and progression and not infrequently BCR-ABL1 kinase domain (KD) mutations are implicated in therapeutic failure. In this setting, earlier detection of emerging BCR-ABL1 KD mutations would offer greater chances of efficacy for subsequent salvage therapy and limit the biological consequences of full BCR-ABL1 kinase reactivation. Taking advantage of an already set up and validated next-generation deep amplicon sequencing (DS) assay, we aimed to assess whether DS may allow a larger window of detection of emerging BCR-ABL1 KD mutants predicting for an impending relapse. a total of 125 longitudinal samples from 51 CML patients who had acquired dasatinib- or nilotinib-resistant mutations during second-line therapy were analyzed by DS from the time of failure and mutation detection by conventional sequencing backwards. BCR-ABL1/ABL1%(IS) transcript levels were used to define whether the patient had 'optimal response', 'warning' or 'failure' at the time of first mutation detection by DS. DS was able to backtrack dasatinib- or nilotinib-resistant mutations to the previous sample(s) in 23/51 (45 %) pts. Median mutation burden at the time of first detection by DS was 5.5 % (range, 1.5-17.5 %); median interval between detection by DS and detection by conventional sequencing was 3 months (range, 1-9 months). In 5 cases, the mutations were detectable at baseline. In the remaining cases, response level at the time mutations were first detected by DS could be defined as 'Warning' (according to the 2013 ELN definitions of response to 2nd-line therapy) in 13 cases, as 'Optimal response' in one case, as 'Failure' in 4 cases. No dasatinib- or nilotinib-resistant mutations were detected by DS in 15 randomly selected patients with 'warning' at various timepoints, that later turned into optimal responders with no treatment changes. DS enables a larger window of detection of emerging BCR-ABL1 KD mutations predicting for an impending relapse. A 'Warning' response may represent a rational trigger, besides 'Failure', for DS-based mutation screening in CML patients undergoing second-line TKI therapy.

In vitro chloramphenicol detection in a Haemophilus influenza model using an aptamer-polymer based electrochemical biosensor.

PubMed

Yadav, Saurabh K; Agrawal, Bharati; Chandra, Pranjal; Goyal, Rajendra N

2014-05-15

A sensitive and selective electrochemical biosensor is developed for the determination of chloramphenicol (CAP) exploring its direct electron transfer processes in in-vitro model and pharmaceutical samples. This biosensor exploits a selective binding of CAP with aptamer, immobilized onto the poly-(4-amino-3-hydroxynapthalene sulfonic acid) (p-AHNSA) modified edge plane pyrolytic graphite. The electrochemical reduction of CAP was observed in a well-defined peak. A quartz crystal microbalance (QCM) study is performed to confirm the interaction between the polymer film and the aptamer. Cyclic voltammetry (CV) and square wave voltammetry (SWV) were used to detect CAP. The in-vitro CAP detection is performed using the bacterial strain of Haemophilus influenza. A significant accumulation of CAP by the drug sensitive H. influenza strain is observed for the first time in this study using a biosensor. Various parameters affecting the CAP detection in standard solution and in in vitro detection are optimized. The detection of CAP is linear in the range of 0.1-2500 nM with the detection limit and sensitivity of 0.02 nM and 0.102 µA/nM, respectively. CAP is also detected in the presence of other common antibiotics and proteins present in the real sample matrix, and negligible interference is observed. Copyright © 2013 Elsevier B.V. All rights reserved.

Performance of gout definitions for genetic epidemiological studies: analysis of UK Biobank.

PubMed

Cadzow, Murray; Merriman, Tony R; Dalbeth, Nicola

2017-08-09

Many different combinations of available data have been used to identify gout cases in large genetic studies. The aim of this study was to determine the performance of case definitions of gout using the limited items available in multipurpose cohorts for population-based genetic studies. This research was conducted using the UK Biobank Resource. Data, including genome-wide genotypes, were available for 105,421 European participants aged 40-69 years without kidney disease. Gout definitions and combinations of these definitions were identified from previous epidemiological studies. These definitions were tested for association with 30 urate-associated single-nucleotide polymorphisms (SNPs) by logistic regression, adjusted for age, sex, waist circumference, and ratio of waist circumference to height. Heritability estimates under an additive model were generated using GCTA version 1.26.0 and PLINK version 1.90b3.32 by partitioning the genome. There were 2066 (1.96%) cases defined by self-report of gout, 1652 (1.57%) defined by urate-lowering therapy (ULT) use, 382 (0.36%) defined by hospital diagnosis, 1861 (1.76%) defined by hospital diagnosis or gout-specific medications and 2295 (2.18%) defined by self-report of gout or ULT use. Association with gout at experiment-wide significance (P < 0.0017) was observed for 13 SNPs with gout using the self-report of gout or ULT use definition, 12 SNPs using the self-report of gout definition, 11 SNPs using the hospital diagnosis or gout-specific medication definition, 10 SNPs using ULT use definition and 3 SNPs using hospital diagnosis definition. Heritability estimates ranged from 0.282 to 0.308 for all definitions except hospital diagnosis (0.236). Of the limited items available in multipurpose cohorts, the case definition of self-report of gout or ULT use has high sensitivity and precision for detecting association in genetic epidemiological studies of gout.

A computer-aided detection (CAD) system with a 3D algorithm for small acute intracranial hemorrhage

NASA Astrophysics Data System (ADS)

Wang, Ximing; Fernandez, James; Deshpande, Ruchi; Lee, Joon K.; Chan, Tao; Liu, Brent

2012-02-01

Acute Intracranial hemorrhage (AIH) requires urgent diagnosis in the emergency setting to mitigate eventual sequelae. However, experienced radiologists may not always be available to make a timely diagnosis. This is especially true for small AIH, defined as lesion smaller than 10 mm in size. A computer-aided detection (CAD) system for the detection of small AIH would facilitate timely diagnosis. A previously developed 2D algorithm shows high false positive rates in the evaluation based on LAC/USC cases, due to the limitation of setting up correct coordinate system for the knowledge-based classification system. To achieve a higher sensitivity and specificity, a new 3D algorithm is developed. The algorithm utilizes a top-hat transformation and dynamic threshold map to detect small AIH lesions. Several key structures of brain are detected and are used to set up a 3D anatomical coordinate system. A rule-based classification of the lesion detected is applied based on the anatomical coordinate system. For convenient evaluation in clinical environment, the CAD module is integrated with a stand-alone system. The CAD is evaluated by small AIH cases and matched normal collected in LAC/USC. The result of 3D CAD and the previous 2D CAD has been compared.

Surge detection on an automotive turbocharger during transient phases

NASA Astrophysics Data System (ADS)

Deligant, M.; Danlos, A.; Podevin, P.; Clenci, A.; Guilain, S.

2017-10-01

The surge limit on automotive turbocharger needs to be avoided to prevent operations with pressure and mass flow oscillations. Mild surge is accompanied by noise which is disturbing. Deep surge can cause significant loss of engine power and severe drivability issues. It is necessary to know the stationary limit in order to match a turbocharger with an engine, ensuring enough surge margin. However, this choice does not guarantee surge free operation during transient functioning. In this paper, the surge onset of a compressor while closing a downstream valve is studied. Various tests have been carried out varying the closing time, the position of the initial operating point and the volume of the circuit. The inlet and outlet signals of physical parameters are analyzed with spectral and temporal methods in order to define the instant of the surge occurrence.

Multisensor fusion for the detection of mines and minelike targets

NASA Astrophysics Data System (ADS)

Hanshaw, Terilee

1995-06-01

The US Army's Communications and Electronics Command through the auspices of its Night Vision and Electronics Sensors Directorate (CECOM-NVESD) is actively applying multisensor techniques to the detection of mine targets. This multisensor research results from the 'detection activity' with its broad range of operational conditions and targets. Multisensor operation justifies significant attention by yielding high target detection and low false alarm statistics. Furthermore, recent advances in sensor and computing technologies make its practical application realistic and affordable. The mine detection field-of-endeavor has since its WWI baptismal investigated the known spectra for applicable mine observation phenomena. Countless sensors, algorithms, processors, networks, and other techniques have been investigated to determine candidacy for mine detection. CECOM-NVESD efforts have addressed a wide range of sensors spanning the spectrum from gravity field perturbations, magentic field disturbances, seismic sounding, electromagnetic fields, earth penetrating radar imagery, and infrared/visible/ultraviolet surface imaging technologies. Supplementary analysis has considered sensor candidate applicability by testing under field conditions (versus laboratory), in determination of fieldability. As these field conditions directly effect the probability of detection and false alarms, sensor employment and design must be considered. Consequently, as a given sensor's performance is influenced directly by the operational conditions, tradeoffs are necessary. At present, mass produced and fielded mine detection techniques are limited to those incorporating a single sensor/processor methodology such as, pulse induction and megnetometry, as found in hand held detectors. The most sensitive fielded systems can detect minute metal components in small mine targets but result in very high false alarm rates reducing velocity in operation environments. Furthermore, the actual speed of advance for the entire mission (convoy, movement to engagement, etc.) is determined by the level of difficulty presented in clearance or avoidance activities required in response to the potential 'targets' marked throughout a detection activity. Therefore the application of fielded hand held systems to convoy operations in clearly impractical. CECOM-NVESD efforts are presently seeking to overcome these operational limitations by substantially increasing speed of detection while reducing the false alarm rate through the application of multisensor techniques. The CECOM-NVESD application of multisensor techniques through integration/fusion methods will be defined in this paper.

Baseline predictability of daily east Asian summer monsoon circulation indices

NASA Astrophysics Data System (ADS)

Ai, Shucong; Chen, Quanliang; Li, Jianping; Ding, Ruiqiang; Zhong, Quanjia

2017-05-01

The nonlinear local Lyapunov exponent (NLLE) method is adopted to quantitatively determine the predictability limit of East Asian summer monsoon (EASM) intensity indices on a synoptic timescale. The predictability limit of EASM indices varies widely according to the definitions of indices. EASM indices defined by zonal shear have a limit of around 7 days, which is higher than the predictability limit of EASM indices defined by sea level pressure (SLP) difference and meridional wind shear (about 5 days). The initial error of EASM indices defined by SLP difference and meridional wind shear shows a faster growth than indices defined by zonal wind shear. Furthermore, the indices defined by zonal wind shear appear to fluctuate at lower frequencies, whereas the indices defined by SLP difference and meridional wind shear generally fluctuate at higher frequencies. This result may explain why the daily variability of the EASM indices defined by zonal wind shear tends be more predictable than those defined by SLP difference and meridional wind shear. Analysis of the temporal correlation coefficient (TCC) skill for EASM indices obtained from observations and from NCEP's Global Ensemble Forecasting System (GEFS) historical weather forecast dataset shows that GEFS has a higher forecast skill for the EASM indices defined by zonal wind shear than for indices defined by SLP difference and meridional wind shear. The predictability limit estimated by the NLLE method is shorter than that in GEFS. In addition, the June-September average TCC skill for different daily EASM indices shows significant interannual variations from 1985 to 2015 in GEFS. However, the TCC for different types of EASM indices does not show coherent interannual fluctuations.

Natural history of optical coherence tomography-detected non-flow-limiting edge dissections following drug-eluting stent implantation.

PubMed

Radu, Maria D; Räber, Lorenz; Heo, Jungho; Gogas, Bill D; Jørgensen, Erik; Kelbæk, Henning; Muramatsu, Takashi; Farooq, Vasim; Helqvist, Steffen; Garcia-Garcia, Hector M; Windecker, Stephan; Saunamäki, Kari; Serruys, Patrick W

2014-01-22

Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections--particularly non-flow-limiting--compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

The missing GeV γ-ray binary: Searching for HESS J0632+057 with Fermi-LAT

DOE PAGES

Caliandro, G. A.; Hill, A. B.; Torres, D. F.; ...

2013-09-25

The very high energy (VHE; >100 GeV) source HESS J0632+057 has been recently confirmed as a γ-ray binary, a subclass of the high-mass X-ray binary population, through the detection of an orbital period of 321 d. We performed a deep search for the emission of HESS J0632+057 in the GeV energy range using data from the Fermi Large Area Telescope (LAT). The analysis was challenging due to the source being located in close proximity to the bright γ-ray pulsar PSR J0633+0632 and lying in a crowded region of the Galactic plane where there is prominent diffuse emission. We formulated amore » Bayesian block algorithm adapted to work with weighted photon counts, in order to define the off-pulse phases of PSR J0633+0632. A detailed spectral-spatial model of a 5° circular region centred on the known location of HESS J0632+057 was generated to accurately model the LAT data. No significant emission from the location of HESS J0632+057 was detected in the 0.1–100 GeV energy range integrating over ~3.5 yr of data, with a 95 per cent flux upper limit of F0.1-100 GeV < 3 × 10 –8 ph cm –2 s –1. A search for emission over different phases of the orbit also yielded no significant detection. A search for source emission on shorter time-scales (days–months) did not yield any significant detections. We also report the results of a search for radio pulsations using the 100-m Green Bank Telescope. No periodic signals or individual dispersed bursts of a likely astronomical origin were detected. We estimated the flux density limit of < 90/40 μJy at 2/9 GHz. Furthermore, the LAT flux upper limits combined with the detection of HESS J0632+057 in the 136–400 TeV energy band by the MAGIC collaboration imply that the VHE spectrum must turn over at energies <136 GeV placing constraints on any theoretical models invoked to explain the γ-ray emission.« less

Differential cross-reactivity of monoclonal antibody OPD4 (anti-CD45RO) in macaques.

PubMed

Wang, Xiaolei; Pahar, Bapi; Rasmussen, Terri; Alvarez, Xavier; Dufour, Jason; Rasmussen, Kelsi; Lackner, Andrew A; Veazey, Ronald S

2008-01-01

Immunologic research in nonhuman primates is occasionally limited by the availability of reagents that cross-react in nonhuman primates. One major limitation has been the lack of a monoclonal antibody to CD45RO. Although the monoclonal antibody UCHL-1 is used to detect CD45RO isoforms in humans, it does not react with nonhuman primates, mandating the use of alternative strategies to define "memory" T cell responses in nonhuman primates. The current study examined the reactivity and specificity of another antibody against CD45RO, clone OPD4, in macaques. Here we demonstrate that OPD4 specifically labels memory CD4+ T cells in approximately 44% of rhesus macaques (Macaca mulatta) of Indian but not Chinese origin. In contrast, tissues from pigtail macaques (Macaca nemestrina) react with this clone, indicating that OPD4 may be useful for examining memory CD4+ T cells in certain macaques, but its utility may be limited in other species or even among individual macaques.

Differential cross-reactivity of monoclonal antibody OPD4 (anti-CD45RO) in macaques

PubMed Central

Wang, Xiaolei; Pahar, Bapi; Rasmussen, Terri; Alvarez, Xavier; Dufour, Jason; Rasmussen, Kelsi; Lackner, Andrew A.; Veazey, Ronald S.

2008-01-01

Immunologic research in nonhuman primates is occasionally limited by the availability of reagents that cross react in nonhuman primates. One major limitation has been the lack of a monoclonal antibody to CD45RO. Although the monoclonal antibody UCHL-1 is used to detect CD45RO isoforms in humans, it does not react with nonhuman primates, mandating the use of alternative strategies to define “memory” T cell responses in nonhuman primates. The current study examined the reactivity and specificity of another antibody against CD45RO, clone OPD4, in macaques. Here we demonstrate that OPD4 specifically labels memory CD4+ T cells in ~44% of rhesus macaques (Macaca mulatta) of Indian, but not Chinese origin. In contrast, tissues from pigtail macaques (Macaca nemestrina) react with this clone, indicating that OPD4 may be useful for examining memory CD4+ T cells in certain macaques, but its utility may be limited in other species or even among individual macaques. PMID:18304631

Rotationally resolved spectroscopy of Jupiter Trojans (624) Hektor and (911) Agamemnon

NASA Astrophysics Data System (ADS)

Perna, D.; Bott, N.; Hromakina, T.; Mazzotta Epifani, E.; Dotto, E.; Doressoundiram, A.

2018-03-01

We present the first-ever rotationally resolved spectroscopic investigation of (624) Hektor and (911) Agamemnon, the two largest Jupiter Trojans. The visible and near-infrared spectra that we have obtained at the TNG telescope (La Palma, Spain) do not show any feature or hints of heterogeneity. In particular, we found no hints of water-related absorptions. No cometary activity was detected down to ˜23.5 R mag arcsec-2 based on the complementary photometric data. We estimated upper limits on the dust production rates of Hektor and Agamemnon to be ≈30 and ≈24 kg s-1, respectively. We modelled complete visible and near-infrared spectra of our targets using the Shkuratov formalism to define the upper limit to the presence of water ice and more in general to constrain their surface composition. For both objects, successful models include amorphous carbon, magnesium-rich pyroxene, and kerogen, with an upper limit to the amount of water ice of a few per cent.

Figure-ground segregation by motion contrast and by luminance contrast.

PubMed

Regan, D; Beverley, K I

1984-05-01

Some naturally camouflaged objects are invisible unless they move; their boundaries are then defined by motion contrast between object and background. We compared the visual detection of such camouflaged objects with the detection of objects whose boundaries were defined by luminance contrast. The summation field area is 0.16 deg2 , and the summation time constant is 750 msec for parafoveally viewed objects whose boundaries are defined by motion contrast; these values are, respectively, about 5 and 12 times larger than the corresponding values for objects defined by luminance contrast. The log detection threshold is proportional to the eccentricity for a camouflaged object of constant area. The effect of eccentricity on threshold is less for large objects than for small objects. The log summation field diameter for detecting camouflaged objects is roughly proportional to the eccentricity, increasing to about 20 deg at 32-deg eccentricity. In contrast to the 100:1 increase of summation area for detecting camouflaged objects, the temporal summation time constant changes by only 40% between eccentricities of 0 and 16 deg.

The Time-Domain Matched Filter and the Spectral-Domain Matched Filter in 1-Dimensional NMR Spectroscopy.

PubMed

Spencer, Richard G

2010-09-01

A type of "matched filter" (MF), used extensively in the processing of one-dimensional spectra, is defined by multiplication of a free-induction decay (FID) by a decaying exponential with the same time constant as that of the FID. This maximizes, in a sense to be defined, the signal-to-noise ratio (SNR) in the spectrum obtained after Fourier transformation. However, a different entity known also as the matched filter was introduced by van Vleck in the context of pulse detection in the 1940's and has become widely integrated into signal processing practice. These two types of matched filters appear to be quite distinct. In the NMR case, the "filter", that is, the exponential multiplication, is defined by the characteristics of, and applied to, a time domain signal in order to achieve improved SNR in the spectral domain. In signal processing, the filter is defined by the characteristics of a signal in the spectral domain, and applied in order to improve the SNR in the temporal (pulse) domain. We reconcile these two distinct implementations of the matched filter, demonstrating that the NMR "matched filter" is a special case of the matched filter more rigorously defined in the signal processing literature. In addition, two limitations in the use of the MF are highlighted. First, application of the MF distorts resonance ratios as defined by amplitudes, although not as defined by areas. Second, the MF maximizes SNR with respect to resonance amplitude, while intensities are often more appropriately defined by areas. Maximizing the SNR with respect to area requires a somewhat different approach to matched filtering.

Ajustement automatique des parametres de coupe pour l'obtention de stabilite dynamique en usinage

NASA Astrophysics Data System (ADS)

Tabet, Ricardo

High speed machining has as principal limitation the dynamic stability of the cutting action which can generate premature wear of the machine spindle and the cutting tool, tool breakage and dimensional errors on the machined part. This phenomenon is known in the literature as chatter and is defined as being self-excited vibrations. This master thesis presents an approach applicable to manufacturing environments that allows eliminating chatter in real time during machining of aerospace aluminum alloys before the damaging effect can occur. A control algorithm is developed in order to detect chatter using a microphone and by analyzing the audio signal in the frequency domain. The analysis allows determining precisely the frequency at which the chatter occurs and therefore, the spindle speed is adjusted in order to make the tooth passing frequency equal to the detected chatter frequency. Also, a new feedrate is determined by keeping a constant chip load and within the physical limits of the cutting tool. The new cutting parameters are then sent out to the machine controller as a command using a communication interface between an external computer and the controller. Multiples experimental tests were conducted to validate the effectiveness to detect and suppress chatter. High speed machining tests, between 15 000 and 33 000 RPM, were performed in order to reflect real conditions for aerospace components manufacturing.

Bioconjugation of zirconium uridine monophosphate: application to myoglobin direct electrochemistry.

PubMed

Qiao, Yuanbiao; Jian, Fangfang; Bai, Qian

2008-03-14

Porous nano-granule of zirconium uridine monophosphate, Zr(UMP)2.H2O is, for the first time, synthesized under mild experimental conditions and applied to the bioconjugation of myoglobin (Mb) to realize its direct electron transfer. UV-vis and resonance Raman spectroscopies prove that Mb in the Zr(UMP)2.H2O film maintains its secondary structure similar to the native state. The conjugation film of the Mb-Zr(UMP)2.H2O on the glassy carbon (GC) electrode gives a well-defined and quasi-reversible cyclic voltammogram, which reflects the direct electron transfer of the heme Fe III/Fe II couple of Mb. On the basis of the satisfying bioelectrocatalysis of the nano-conjugation of Mb and genetic substrate, a kind of mediator-free biosensor for H2O2 is developed. The linear range for H2O2 detection is estimated to be 3.92-180.14 microM. The apparent Michaelis-Menten constant (Km) and the detection limit based on the signal-to-noise ratio of 3 are found to be 196.1 microM and 1.52 microM, respectively. Both the apparent Michaelis-Menten constant and the detection limit herein are much lower than currently reported values from other Mb films. This kind of sensor possesses excellent stability, long-term life (more than 20 days) and good reproducibility.

Point-of-care testing for streptomycin based on aptamer recognizing and digital image colorimetry by smartphone.

PubMed

Lin, Bixia; Yu, Ying; Cao, Yujuan; Guo, Manli; Zhu, Debin; Dai, Jiaxing; Zheng, Minshi

2018-02-15

The rapid detection of antibiotic residual in everyday life is very important for food safety. In order to realize the on-site and visual detection of antibiotic, a POCT method was established by using digital image colorimetry based on smartphone. Streptomycin was taken as the analyte model of antibiotics, streptomycin aptamer preferentially recognized analyte, and the excess aptamer hybridized with the complementary DNA to form the dsDNA. SYBR Green I combined with the dsDNA and then emitted obvious green fluorescence, thus the fluorescence intensity decreased with the increasing of streptomycin concentration. Then a smartphone-based device was constructed as the fluorescence readout. The smartphone camera acquired the images of the fluorescence derived from the samples, and the Touch Color APP installed in smartphone read out the RGB values of the images. There was a linear relationship between the G values and the streptomycin concentrations in the range of 0.1-100µM. The detection limit was 94nM, which was lower than the maximum residue limit defined by World Health Organization. The POCT method was applied for determining streptomycin in chicken and milk samples with recoveries in 94.1-110%. This method had the advantages of good selectivity, simple operation and on-site visualization. Copyright © 2017 Elsevier B.V. All rights reserved.

Test and evaluation of the Airport Surveillance Radar (ASR)-8 wind shear detection system (phase 2), revision

NASA Astrophysics Data System (ADS)

Offi, D. L.; Lewis, W.; Lee, T.; Delamarche, A.

1980-08-01

A wind shear detection system developed by the Wave Propagation Laboratory (WPL) to operate with the Federal Aviation Administration (FAA) Airport Surveillance Radar (ASR)-8 was installed and is being tested at the FAA technical Center. Initial efforts, previously reported in Report NA-78-59-LR, were directed toward hardware and software shakedown and feasibility determination. Second phase tests compared radar with aircraft and tower winds, evaluated the wind shear measurement capability under various weather conditions, and investigated the effectiveness of a simple two-azimuth pointing strategy and system capabilities and limitations. Results showed the system to be compatible with and to operate satisfactorily with the ASR-8. The processing and spectral display of clear air and precipitation returns is feasible. The accuracy of agreement between radar-measured winds and components of the aircraft-measured winds in both radially oriented flights and runway offset flights, using a two-azimuth pointing technique, was examined. Radar versus tower wind agreement was also examined. Potentially dangerous wind shears associated with weather during these tests were detectable. Certain system limitations also have been defined and considered. It is recommended that tests continue to complete definition of and demonstrate capabilities in all weather situations, to optimize performance, and to provide information to specify system design for possible development of a prototype model.

Representation of photon limited data in emission tomography using origin ensembles

NASA Astrophysics Data System (ADS)

Sitek, A.

2008-06-01

Representation and reconstruction of data obtained by emission tomography scanners are challenging due to high noise levels in the data. Typically, images obtained using tomographic measurements are represented using grids. In this work, we define images as sets of origins of events detected during tomographic measurements; we call these origin ensembles (OEs). A state in the ensemble is characterized by a vector of 3N parameters Y, where the parameters are the coordinates of origins of detected events in a three-dimensional space and N is the number of detected events. The 3N-dimensional probability density function (PDF) for that ensemble is derived, and we present an algorithm for OE image estimation from tomographic measurements. A displayable image (e.g. grid based image) is derived from the OE formulation by calculating ensemble expectations based on the PDF using the Markov chain Monte Carlo method. The approach was applied to computer-simulated 3D list-mode positron emission tomography data. The reconstruction errors for a 10 000 000 event acquisition for simulated ranged from 0.1 to 34.8%, depending on object size and sampling density. The method was also applied to experimental data and the results of the OE method were consistent with those obtained by a standard maximum-likelihood approach. The method is a new approach to representation and reconstruction of data obtained by photon-limited emission tomography measurements.

A Leveraged Signal-to-Noise Ratio (LSTNR) Method to Extract Differentially Expressed Genes and Multivariate Patterns of Expression From Noisy and Low-Replication RNAseq Data

PubMed Central

Lozoya, Oswaldo A.; Santos, Janine H.; Woychik, Richard P.

2018-01-01

To life scientists, one important feature offered by RNAseq, a next-generation sequencing tool used to estimate changes in gene expression levels, lies in its unprecedented resolution. It can score countable differences in transcript numbers among thousands of genes and between experimental groups, all at once. However, its high cost limits experimental designs to very small sample sizes, usually N = 3, which often results in statistically underpowered analysis and poor reproducibility. All these issues are compounded by the presence of experimental noise, which is harder to distinguish from instrumental error when sample sizes are limiting (e.g., small-budget pilot tests), experimental populations exhibit biologically heterogeneous or diffuse expression phenotypes (e.g., patient samples), or when discriminating among transcriptional signatures of closely related experimental conditions (e.g., toxicological modes of action, or MOAs). Here, we present a leveraged signal-to-noise ratio (LSTNR) thresholding method, founded on generalized linear modeling (GLM) of aligned read detection limits to extract differentially expressed genes (DEGs) from noisy low-replication RNAseq data. The LSTNR method uses an agnostic independent filtering strategy to define the dynamic range of detected aggregate read counts per gene, and assigns statistical weights that prioritize genes with better sequencing resolution in differential expression analyses. To assess its performance, we implemented the LSTNR method to analyze three separate datasets: first, using a systematically noisy in silico dataset, we demonstrated that LSTNR can extract pre-designed patterns of expression and discriminate between “noise” and “true” differentially expressed pseudogenes at a 100% success rate; then, we illustrated how the LSTNR method can assign patient-derived breast cancer specimens correctly to one out of their four reported molecular subtypes (luminal A, luminal B, Her2-enriched and basal-like); and last, we showed the ability to retrieve five different modes of action (MOA) elicited in livers of rats exposed to three toxicants under three nutritional routes by using the LSTNR method. By combining differential measurements with resolving power to detect DEGs, the LSTNR method offers an alternative approach to interrogate noisy and low-replication RNAseq datasets, which handles multiple biological conditions at once, and defines benchmarks to validate RNAseq experiments with standard benchtop assays. PMID:29868123

Using Cognitive Control in Software Defined Networking for Port Scan Detection

DTIC Science & Technology

2017-07-01

ARL-TR-8059 ● July 2017 US Army Research Laboratory Using Cognitive Control in Software-Defined Networking for Port Scan...Cognitive Control in Software-Defined Networking for Port Scan Detection by Vinod K Mishra Computational and Information Sciences Directorate, ARL...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) July 2017 2. REPORT TYPE

New Substrate-Guided Method of Predicting Slow Conducting Isthmuses of Ventricular Tachycardia: Preliminary Analysis to the Combined Use of Voltage Limit Adjustment and Fast-Fourier Transform Analysis.

PubMed

Kuroki, Kenji; Nogami, Akihiko; Igarashi, Miyako; Masuda, Keita; Kowase, Shinya; Kurosaki, Kenji; Komatsu, Yuki; Naruse, Yoshihisa; Machino, Takeshi; Yamasaki, Hiro; Xu, Dongzhu; Murakoshi, Nobuyuki; Sekiguchi, Yukio; Aonuma, Kazutaka

2018-04-01

Several conducting channels of ventricular tachycardia (VT) can be identified using voltage limit adjustment (VLA) of substrate mapping. However, the sensitivity or specificity to predict a VT isthmus is not high by using VLA alone. This study aimed to evaluate the efficacy of the combined use of VLA and fast-Fourier transform analysis to predict VT isthmuses. VLA and fast-Fourier transform analyses of local ventricular bipolar electrograms during sinus rhythm were performed in 9 postinfarction patients who underwent catheter ablation for a total of 13 monomorphic VTs. Relatively higher voltage areas on an electroanatomical map were defined as high voltage channels (HVCs), and relatively higher fast-Fourier transform areas were defined as high-frequency channels (HFCs). HVCs were classified into full or partial HVCs (the entire or >30% of HVC can be detectable, respectively). Twelve full HVCs were identified in 7 of 9 patients. HFCs were located on 7 of 12 full HVCs. Five VT isthmuses (71%) were included in the 7 full HVC+/HFC+ sites, whereas no VT isthmus was found in the 5 full HVC+/HFC- sites. HFCs were identical to 9 of 16 partial HVCs. Eight VT isthmuses (89%) were included in the 9 partial HVC+/HFC+ sites, whereas no VT isthmus was found in the 7 partial HVC+/HFC- sites. All HVC+/HFC+ sites predicted VT isthmus with a sensitivity of 100% and a specificity of 80%. Combined use of VLA and fast-Fourier transform analysis may be a useful method to detect VT isthmuses. © 2018 American Heart Association, Inc.

Ambient Pressure XPS Study of Mixed Conducting Perovskite-Type SOFC Cathode and Anode Materials under Well-Defined Electrochemical Polarization

PubMed Central

2015-01-01

The oxygen exchange activity of mixed conducting oxide surfaces has been widely investigated, but a detailed understanding of the corresponding reaction mechanisms and the rate-limiting steps is largely still missing. Combined in situ investigation of electrochemically polarized model electrode surfaces under realistic temperature and pressure conditions by near-ambient pressure (NAP) XPS and impedance spectroscopy enables very surface-sensitive chemical analysis and may detect species that are involved in the rate-limiting step. In the present study, acceptor-doped perovskite-type La0.6Sr0.4CoO3-δ (LSC), La0.6Sr0.4FeO3-δ (LSF), and SrTi0.7Fe0.3O3-δ (STF) thin film model electrodes were investigated under well-defined electrochemical polarization as cathodes in oxidizing (O2) and as anodes in reducing (H2/H2O) atmospheres. In oxidizing atmosphere all materials exhibit additional surface species of strontium and oxygen. The polaron-type electronic conduction mechanism of LSF and STF and the metal-like mechanism of LSC are reflected by distinct differences in the valence band spectra. Switching between oxidizing and reducing atmosphere as well as electrochemical polarization cause reversible shifts in the measured binding energy. This can be correlated to a Fermi level shift due to variations in the chemical potential of oxygen. Changes of oxidation states were detected on Fe, which appears as FeIII in oxidizing atmosphere and as mixed FeII/III in H2/H2O. Cathodic polarization in reducing atmosphere leads to the reversible formation of a catalytically active Fe0 phase. PMID:26877827

Stereo and photometric image sequence interpretation for detecting negative obstacles using active gaze control and performing an autonomous jink

NASA Astrophysics Data System (ADS)

Hofmann, Ulrich; Siedersberger, Karl-Heinz

2003-09-01

Driving cross-country, the detection and state estimation relative to negative obstacles like ditches and creeks is mandatory for safe operation. Very often, ditches can be detected both by different photometric properties (soil vs. vegetation) and by range (disparity) discontinuities. Therefore, algorithms should make use of both the photometric and geometric properties to reliably detect obstacles. This has been achieved in UBM's EMS-Vision System (Expectation-based, Multifocal, Saccadic) for autonomous vehicles. The perception system uses Sarnoff's image processing hardware for real-time stereo vision. This sensor provides both gray value and disparity information for each pixel at high resolution and framerates. In order to perform an autonomous jink, the boundaries of an obstacle have to be measured accurately for calculating a safe driving trajectory. Especially, ditches are often very extended, so due to the restricted field of vision of the cameras, active gaze control is necessary to explore the boundaries of an obstacle. For successful measurements of image features the system has to satisfy conditions defined by the perception expert. It has to deal with the time constraints of the active camera platform while performing saccades and to keep the geometric conditions defined by the locomotion expert for performing a jink. Therefore, the experts have to cooperate. This cooperation is controlled by a central decision unit (CD), which has knowledge about the mission and the capabilities available in the system and of their limitations. The central decision unit reacts dependent on the result of situation assessment by starting, parameterizing or stopping actions (instances of capabilities). The approach has been tested with the 5-ton van VaMoRs. Experimental results will be shown for driving in a typical off-road scenario.

Development of a data independent acquisition mass spectrometry workflow to enable glycopeptide analysis without predefined glycan compositional knowledge.

PubMed

Lin, Chi-Hung; Krisp, Christoph; Packer, Nicolle H; Molloy, Mark P

2018-02-10

Glycoproteomics investigates glycan moieties in a site specific manner to reveal the functional roles of protein glycosylation. Identification of glycopeptides from data-dependent acquisition (DDA) relies on high quality MS/MS spectra of glycopeptide precursors and often requires manual validation to ensure confident assignments. In this study, we investigated pseudo-MRM (MRM-HR) and data-independent acquisition (DIA) as alternative acquisition strategies for glycopeptide analysis. These approaches allow data acquisition over the full MS/MS scan range allowing data re-analysis post-acquisition, without data re-acquisition. The advantage of MRM-HR over DDA for N-glycopeptide detection was demonstrated from targeted analysis of bovine fetuin where all three N-glycosylation sites were detected, which was not the case with DDA. To overcome the duty cycle limitation of MRM-HR acquisition needed for analysis of complex samples such as plasma we trialed DIA. This allowed development of a targeted DIA method to identify N-glycopeptides without pre-defined knowledge of the glycan composition, thus providing the potential to identify N-glycopeptides with unexpected structures. This workflow was demonstrated by detection of 59 N-glycosylation sites from 41 glycoproteins from a HILIC enriched human plasma tryptic digest. 21 glycoforms of IgG1 glycopeptides were identified including two truncated structures that are rarely reported. We developed a data-independent mass spectrometry workflow to identify specific glycopeptides from complex biological mixtures. The novelty is that this approach does not require glycan composition to be pre-defined, thereby allowing glycopeptides carrying unexpected glycans to be identified. This is demonstrated through the analysis of immunoglobulins in human plasma where we detected two IgG1 glycoforms that are rarely observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative analysis of detection limits and specificity of molecular diagnostic markers for three pathogens (Microsporidia, Nosema spp.) in the key pollinators Apis mellifera and Bombus terrestris.

PubMed

Erler, Silvio; Lommatzsch, Stefanie; Lattorff, H Michael G

2012-04-01

Global pollinator decline has recently been discussed in the context of honey and bumble bee infections from various pathogens including viruses, bacteria, microsporidia and mites. The microsporidian pathogens Nosema apis, Nosema ceranae and Nosema bombi may in fact be major candidates contributing to this decline. Different molecular and non-molecular detection methods have been developed; however, a comparison, especially of the highly sensitive PCR based methods, is currently lacking. Here, we present the first comparative quantitative real-time PCR study of nine Nosema spp. primers within the framework of primer specificity and sensitivity. With the help of dilution series of defined numbers of spores, we reveal six primer pairs amplifying N. apis, six for N. bombi and four for N. ceranae. All appropriate primer pairs detected an amount of at least 10(4) spores, the majority of which were even as sensitive to detect such low amounts as 10(3) to ten spores. Species specificity of primers was observed for N. apis and N. bombi, but not for N. ceranae. Additionally, we did not find any significant correlation for the amplified fragments with PCR efficiency or the limit of detection. We discuss our findings on the background of false positive and negative results using quantitative real-time PCR. On the basis of these results, future research might be based on appropriate primer selection depending on the experimental needs. Primers may be selected on the basis of specificity or sensitivity. Pathogen species and load may be determined with higher precision enhancing all kinds of diagnostic studies.

Exploring the limits of identifying sub-pixel thermal features using ASTER TIR data

USGS Publications Warehouse

Vaughan, R.G.; Keszthelyi, L.P.; Davies, A.G.; Schneider, D.J.; Jaworowski, C.; Heasler, H.

2010-01-01

Understanding the characteristics of volcanic thermal emissions and how they change with time is important for forecasting and monitoring volcanic activity and potential hazards. Satellite instruments view volcanic thermal features across the globe at various temporal and spatial resolutions. Thermal features that may be a precursor to a major eruption, or indicative of important changes in an on-going eruption can be subtle, making them challenging to reliably identify with satellite instruments. The goal of this study was to explore the limits of the types and magnitudes of thermal anomalies that could be detected using satellite thermal infrared (TIR) data. Specifically, the characterization of sub-pixel thermal features with a wide range of temperatures is considered using ASTER multispectral TIR data. First, theoretical calculations were made to define a "thermal mixing detection threshold" for ASTER, which quantifies the limits of ASTER's ability to resolve sub-pixel thermal mixing over a range of hot target temperatures and % pixel areas. Then, ASTER TIR data were used to model sub-pixel thermal features at the Yellowstone National Park geothermal area (hot spring pools with temperatures from 40 to 90 ??C) and at Mount Erebus Volcano, Antarctica (an active lava lake with temperatures from 200 to 800 ??C). Finally, various sources of uncertainty in sub-pixel thermal calculations were quantified for these empirical measurements, including pixel resampling, atmospheric correction, and background temperature and emissivity assumptions.

Esophageal Cancer: Associations with pN+

PubMed Central

Rice, Thomas W.; Ishwaran, Hemant; Hofstetter, Wayne L.; Schipper, Paul H.; Kesler, Kenneth A.; Law, Simon; Lerut, Toni E.M.R.; Denlinger, Chadrick E.; Salo, Jarmo A.; Scott, Walter J.; Watson, Thomas J.; Allen, Mark S.; Chen, Long-Qi; Rusch, Valerie W.; Cerfolio, Robert J.; Luketich, James D.; Duranceau, Andre; Darling, Gail E.; Pera, Manuel; Apperson-Hansen, Carolyn; Blackstone, Eugene H.

2017-01-01

Objectives 1) To identify the association of positive lymph node metastases (pN+), number of positive nodes, and pN subclassification with cancer, treatment, patient, geographic, and institutional variables, and 2) to recommend extent of lymphadenectomy needed to accurately detect pN+ for esophageal cancer. Summary Background Data Limited data and traditional analytic techniques have precluded identifying intricate associations of pN+ with other cancer, treatment, and patient characteristics. Methods Data on 5,806 esophagectomy patients from the Worldwide Esophageal Cancer Collaboration (WECC) were analyzed by Random Forest machine learning techniques. Results pN+, number of positive nodes, and pN subclassification were associated with increasing depth of cancer invasion (pT), increasing cancer length, decreasing cancer differentiation (G), and more regional lymph nodes resected. Lymphadenectomy necessary to accurately detect pN+ is 60 for shorter, well-differentiated cancers (<2.5 cm) and 20 for longer, poorly differentiated ones. Conclusions In esophageal cancer, pN+, increasing number of positive nodes, and increasing pN classification are associated with deeper invading, longer, and poorly differentiated cancers. Consequently, if the goal of lymphadenectomy is to accurately define pN+ status of such cancers, few nodes need to be removed. Conversely, superficial, shorter, and well-differentiated cancers require a more extensive lymphadenectomy to accurately define pN+ status. PMID:28009736

Impact of voxel size variation on CBCT-based diagnostic outcome in dentistry: a systematic review.

PubMed

Spin-Neto, Rubens; Gotfredsen, Erik; Wenzel, Ann

2013-08-01

The objective of this study was to make a systematic review on the impact of voxel size in cone beam computed tomography (CBCT)-based image acquisition, retrieving evidence regarding the diagnostic outcome of those images. The MEDLINE bibliographic database was searched from 1950 to June 2012 for reports comparing diverse CBCT voxel sizes. The search strategy was limited to English-language publications using the following combined terms in the search strategy: (voxel or FOV or field of view or resolution) and (CBCT or cone beam CT). The results from the review identified 20 publications that qualitatively or quantitatively assessed the influence of voxel size on CBCT-based diagnostic outcome, and in which the methodology/results comprised at least one of the expected parameters (image acquisition, reconstruction protocols, type of diagnostic task, and presence of a gold standard). The diagnostic task assessed in the studies was diverse, including the detection of root fractures, the detection of caries lesions, and accuracy of 3D surface reconstruction and of bony measurements, among others. From the studies assessed, it is clear that no general protocol can be yet defined for CBCT examination of specific diagnostic tasks in dentistry. Rationale in this direction is an important step to define the utility of CBCT imaging.

Bioanalytical procedures for monitoring in utero drug exposure

PubMed Central

Gray, Teresa

2009-01-01

Drug use by pregnant women has been extensively associated with adverse mental, physical, and psychological outcomes in their exposed children. This manuscript reviews bioanalytical methods for in utero drug exposure monitoring for common drugs of abuse in urine, hair, oral fluid, blood, sweat, meconium, amniotic fluid, umbilical cord tissue, nails, and vernix caseosa; neonatal matrices are particularly emphasized. Advantages and limitations of testing different maternal and neonatal biological specimens including ease and invasiveness of collection, and detection time frames, sensitivities, and specificities are described, and specific references for available analytical methods included. Future research involves identifying metabolites unique to fetal drug metabolism to improve detection rates of in utero drug exposure and determining relationships between the amount, frequency, and timing of drug exposure and drug concentrations in infant biological fluids and tissues. Accurate bioanalytical procedures are vital to defining the scope of and resolving this important public health problem. PMID:17370066

Counter unmanned aerial system testing and evaluation methodology

NASA Astrophysics Data System (ADS)

Kouhestani, C.; Woo, B.; Birch, G.

2017-05-01

Unmanned aerial systems (UAS) are increasing in flight times, ease of use, and payload sizes. Detection, classification, tracking, and neutralization of UAS is a necessary capability for infrastructure and facility protection. We discuss test and evaluation methodology developed at Sandia National Laboratories to establish a consistent, defendable, and unbiased means for evaluating counter unmanned aerial system (CUAS) technologies. The test approach described identifies test strategies, performance metrics, UAS types tested, key variables, and the necessary data analysis to accurately quantify the capabilities of CUAS technologies. The tests conducted, as defined by this approach, will allow for the determination of quantifiable limitations, strengths, and weaknesses in terms of detection, tracking, classification, and neutralization. Communicating the results of this testing in such a manner informs decisions by government sponsors and stakeholders that can be used to guide future investments and inform procurement, deployment, and advancement of such systems into their specific venues.

Symmetry as Bias: Rediscovering Special Relativity

NASA Technical Reports Server (NTRS)

Lowry, Michael R.

1992-01-01

This paper describes a rational reconstruction of Einstein's discovery of special relativity, validated through an implementation: the Erlanger program. Einstein's discovery of special relativity revolutionized both the content of physics and the research strategy used by theoretical physicists. This research strategy entails a mutual bootstrapping process between a hypothesis space for biases, defined through different postulated symmetries of the universe, and a hypothesis space for physical theories. The invariance principle mutually constrains these two spaces. The invariance principle enables detecting when an evolving physical theory becomes inconsistent with its bias, and also when the biases for theories describing different phenomena are inconsistent. Structural properties of the invariance principle facilitate generating a new bias when an inconsistency is detected. After a new bias is generated. this principle facilitates reformulating the old, inconsistent theory by treating the latter as a limiting approximation. The structural properties of the invariance principle can be suitably generalized to other types of biases to enable primal-dual learning.

[Breast tomosynthesis: a new tool for diagnosing breast cancer].

PubMed

Martínez Miravete, P; Etxano, J

2015-01-01

Breast cancer continues to be the most common malignant tumor in women in occidental countries. Mammography is currently the technique of choice for screening programs; however, although it has been widely validated, mammography has its limitations, especially in dense breasts. Breast tomosynthesis is a revolutionary advance in the diagnosis of breast cancer. It makes it possible to define lesions that are occult in the glandular tissue and therefore to detect breast tumors that are impossible to see on conventional mammograms. In considering the combined use of mammography and tomosynthesis, many factors must be taken into account apart from cancer detection; these include additional radiation, the recall rate, and the time necessary to carry out and interpret the two tests. In this article, we review the technical principles of tomosynthesis, it main uses, and the future perspective for this imaging technique. Copyright © 2013 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Collection and chemical composition of phloem sap from Citrus sinensis L. Osbeck (sweet orange).

PubMed

Hijaz, Faraj; Killiny, Nabil

2014-01-01

Through utilizing the nutrient-rich phloem sap, sap feeding insects such as psyllids, leafhoppers, and aphids can transmit many phloem-restricted pathogens. On the other hand, multiplication of phloem-limited, uncultivated bacteria such as Candidatus Liberibacter asiaticus (CLas) inside the phloem of citrus indicates that the sap contains all the essential nutrients needed for the pathogen growth. The phloem sap composition of many plants has been studied; however, to our knowledge, there is no available data about citrus phloem sap. In this study, we identified and quantified the chemical components of phloem sap from pineapple sweet orange. Two approaches (EDTA enhanced exudation and centrifugation) were used to collect phloem sap. The collected sap was derivatized with methyl chloroformate (MCF), N-methyl-N- [tert-butyl dimethylsilyl]-trifluroacetamide (MTBSTFA), or trimethylsilyl (TMS) and analyzed with GC-MS revealing 20 amino acids and 8 sugars. Proline, the most abundant amino acid, composed more than 60% of the total amino acids. Tryptophan, tyrosine, leucine, isoleucine, and valine, which are considered essential for phloem sap-sucking insects, were also detected. Sucrose, glucose, fructose, and inositol were the most predominant sugars. In addition, seven organic acids including succinic, fumaric, malic, maleic, threonic, citric, and quinic were detected. All compounds detected in the EDTA-enhanced exudate were also detected in the pure phloem sap using centrifugation. The centrifugation technique allowed estimating the concentration of metabolites. This information expands our knowledge about the nutrition requirement for citrus phloem-limited bacterial pathogen and their vectors, and can help define suitable artificial media to culture them.

Collection and Chemical Composition of Phloem Sap from Citrus sinensis L. Osbeck (Sweet Orange)

PubMed Central

Hijaz, Faraj; Killiny, Nabil

2014-01-01

Through utilizing the nutrient-rich phloem sap, sap feeding insects such as psyllids, leafhoppers, and aphids can transmit many phloem-restricted pathogens. On the other hand, multiplication of phloem-limited, uncultivated bacteria such as Candidatus Liberibacter asiaticus (CLas) inside the phloem of citrus indicates that the sap contains all the essential nutrients needed for the pathogen growth. The phloem sap composition of many plants has been studied; however, to our knowledge, there is no available data about citrus phloem sap. In this study, we identified and quantified the chemical components of phloem sap from pineapple sweet orange. Two approaches (EDTA enhanced exudation and centrifugation) were used to collect phloem sap. The collected sap was derivatized with methyl chloroformate (MCF), N-methyl-N- [tert-butyl dimethylsilyl]-trifluroacetamide (MTBSTFA), or trimethylsilyl (TMS) and analyzed with GC-MS revealing 20 amino acids and 8 sugars. Proline, the most abundant amino acid, composed more than 60% of the total amino acids. Tryptophan, tyrosine, leucine, isoleucine, and valine, which are considered essential for phloem sap-sucking insects, were also detected. Sucrose, glucose, fructose, and inositol were the most predominant sugars. In addition, seven organic acids including succinic, fumaric, malic, maleic, threonic, citric, and quinic were detected. All compounds detected in the EDTA-enhanced exudate were also detected in the pure phloem sap using centrifugation. The centrifugation technique allowed estimating the concentration of metabolites. This information expands our knowledge about the nutrition requirement for citrus phloem-limited bacterial pathogen and their vectors, and can help define suitable artificial media to culture them. PMID:25014027

Detecting Unknown Artificial Urban Surface Materials Based on Spectral Dissimilarity Analysis.

PubMed

Jilge, Marianne; Heiden, Uta; Habermeyer, Martin; Mende, André; Juergens, Carsten

2017-08-08

High resolution imaging spectroscopy data have been recognised as a valuable data resource for augmenting detailed material inventories that serve as input for various urban applications. Image-specific urban spectral libraries are successfully used in urban imaging spectroscopy studies. However, the regional- and sensor-specific transferability of such libraries is limited due to the wide range of different surface materials. With the developed methodology, incomplete urban spectral libraries can be utilised by assuming that unknown surface material spectra are dissimilar to the known spectra in a basic spectral library (BSL). The similarity measure SID-SCA (Spectral Information Divergence-Spectral Correlation Angle) is applied to detect image-specific unknown urban surfaces while avoiding spectral mixtures. These detected unknown materials are categorised into distinct and identifiable material classes based on their spectral and spatial metrics. Experimental results demonstrate a successful redetection of material classes that had been previously erased in order to simulate an incomplete BSL. Additionally, completely new materials e.g., solar panels were identified in the data. It is further shown that the level of incompleteness of the BSL and the defined dissimilarity threshold are decisive for the detection of unknown material classes and the degree of spectral intra-class variability. A detailed accuracy assessment of the pre-classification results, aiming to separate natural and artificial materials, demonstrates spectral confusions between spectrally similar materials utilizing SID-SCA. However, most spectral confusions occur between natural or artificial materials which are not affecting the overall aim. The dissimilarity analysis overcomes the limitations of working with incomplete urban spectral libraries and enables the generation of image-specific training databases.

Rayleigh-wave diffractions due to a void in the layered half space

USGS Publications Warehouse

Xia, J.; Xu, Y.; Miller, R.D.; Nyquist, Jonathan E.

2006-01-01

Void detection is challenging due to the complexity of near-surface materials and the limited resolution of geophysical methods. Although multichannel, high-frequency, surface-wave techniques can provide reliable shear (S)-wave velocities in different geological settings, they are not suitable for detecting voids directly based on anomalies of the S-wave velocity because of limitations on the resolution of S-wave velocity profiles inverted from surface-wave phase velocities. Xia et al. (2006a) derived a Rayleigh-wave diffraction traveltime equation due to a void in the homogeneous half space. Encouraging results of directly detecting a void from Rayleigh-wave diffractions were presented (Xia et al., 2006a). In this paper we used four two-dimensional square voids in the layered half space to demonstrate the feasibility of detecting a void with Rayleigh-wave diffractions. Rayleigh-wave diffractions were recognizable for all these models after removing direct surface waves by F-K filtering. We evaluate the feasibility of applying the Rayleigh-wave diffraction traveltime equation to a void in the layered earth model. The phase velocity of diffracted Rayleigh waves is predominately determined by surrounding materials of a void. The modeling results demonstrate that the Rayleigh-wave diffraction traveltime equation due to a void in the homogeneous half space can be applied to the case of a void in the layered half space. In practice, only two diffraction times are necessary to define the depth to the top of a void and the average velocity of diffracted Rayleigh waves. ?? 2005 Society of Exploration Geophysicists.

Detecting Unknown Artificial Urban Surface Materials Based on Spectral Dissimilarity Analysis

PubMed Central

Jilge, Marianne; Heiden, Uta; Habermeyer, Martin; Mende, André; Juergens, Carsten

2017-01-01

High resolution imaging spectroscopy data have been recognised as a valuable data resource for augmenting detailed material inventories that serve as input for various urban applications. Image-specific urban spectral libraries are successfully used in urban imaging spectroscopy studies. However, the regional- and sensor-specific transferability of such libraries is limited due to the wide range of different surface materials. With the developed methodology, incomplete urban spectral libraries can be utilised by assuming that unknown surface material spectra are dissimilar to the known spectra in a basic spectral library (BSL). The similarity measure SID-SCA (Spectral Information Divergence-Spectral Correlation Angle) is applied to detect image-specific unknown urban surfaces while avoiding spectral mixtures. These detected unknown materials are categorised into distinct and identifiable material classes based on their spectral and spatial metrics. Experimental results demonstrate a successful redetection of material classes that had been previously erased in order to simulate an incomplete BSL. Additionally, completely new materials e.g., solar panels were identified in the data. It is further shown that the level of incompleteness of the BSL and the defined dissimilarity threshold are decisive for the detection of unknown material classes and the degree of spectral intra-class variability. A detailed accuracy assessment of the pre-classification results, aiming to separate natural and artificial materials, demonstrates spectral confusions between spectrally similar materials utilizing SID-SCA. However, most spectral confusions occur between natural or artificial materials which are not affecting the overall aim. The dissimilarity analysis overcomes the limitations of working with incomplete urban spectral libraries and enables the generation of image-specific training databases. PMID:28786947

Visualization of hospital cleanliness in three Japanese hospitals with a tendency toward long-term care

PubMed Central

2014-01-01

Background Hospital cleanliness in hospitals with a tendency toward long-term care in Japan remains unevaluated. We therefore visualized hospital cleanliness in Japan over a 2-month period by two distinct popular methods: ATP bioluminescence (ATP method) and the standard stamp agar method (stamp method). Methods The surfaces of 752 sites within nurse and patient areas in three hospitals located in a central area of Sapporo, Japan were evaluated by the ATP and stamp methods, and each surface was sampled 8 times in 2 months. These areas were located in different ward units (Internal Medicine, Surgery, and Obstetrics and Gynecology). Detection limits for the ATP and stamp methods were determined by spike experiments with a diluted bacterial solution and a wipe test on student tables not in use during winter vacation, respectively. Values were expressed as the fold change over the detection limit, and a sample with a value higher than the detection limit by either method was defined as positive. Results The detection limits were determined to be 127 relative light units (RLU) per 100 cm2 for the ATP method and 5.3 colony-forming units (CFU) per 10 cm2 for the stamp method. The positive frequency of the ATP and stamp methods was 59.8% (450/752) and 47.7% (359/752), respectively, although no significant difference in the positive frequency among the hospitals was seen. Both methods revealed the presence of a wide range of organic contamination spread via hand touching, including microbial contamination, with a preponderance on the entrance floor and in patient rooms. Interestingly, the data of both methods indicated considerable variability regardless of daily visual assessment with usual wiping, and positive surfaces were irregularly seen. Nurse areas were relatively cleaner than patient areas. Finally, there was no significant correlation between the number of patients or medical personnel in the hospital and organic or microbiological contamination. Conclusions Ongoing daily hospital cleanliness is not sufficient in Japanese hospitals with a tendency toward long-term care. PMID:24593868

Visualization of hospital cleanliness in three Japanese hospitals with a tendency toward long-term care.

PubMed

Watanabe, Reina; Shimoda, Tomoko; Yano, Rika; Hayashi, Yasuhiro; Nakamura, Shinji; Matsuo, Junji; Yamaguchi, Hiroyuki

2014-03-04

Hospital cleanliness in hospitals with a tendency toward long-term care in Japan remains unevaluated. We therefore visualized hospital cleanliness in Japan over a 2-month period by two distinct popular methods: ATP bioluminescence (ATP method) and the standard stamp agar method (stamp method). The surfaces of 752 sites within nurse and patient areas in three hospitals located in a central area of Sapporo, Japan were evaluated by the ATP and stamp methods, and each surface was sampled 8 times in 2 months. These areas were located in different ward units (Internal Medicine, Surgery, and Obstetrics and Gynecology). Detection limits for the ATP and stamp methods were determined by spike experiments with a diluted bacterial solution and a wipe test on student tables not in use during winter vacation, respectively. Values were expressed as the fold change over the detection limit, and a sample with a value higher than the detection limit by either method was defined as positive. The detection limits were determined to be 127 relative light units (RLU) per 100 cm2 for the ATP method and 5.3 colony-forming units (CFU) per 10 cm2 for the stamp method. The positive frequency of the ATP and stamp methods was 59.8% (450/752) and 47.7% (359/752), respectively, although no significant difference in the positive frequency among the hospitals was seen. Both methods revealed the presence of a wide range of organic contamination spread via hand touching, including microbial contamination, with a preponderance on the entrance floor and in patient rooms. Interestingly, the data of both methods indicated considerable variability regardless of daily visual assessment with usual wiping, and positive surfaces were irregularly seen. Nurse areas were relatively cleaner than patient areas. Finally, there was no significant correlation between the number of patients or medical personnel in the hospital and organic or microbiological contamination. Ongoing daily hospital cleanliness is not sufficient in Japanese hospitals with a tendency toward long-term care.

Spacetime from Entanglement

NASA Astrophysics Data System (ADS)

Swingle, Brian

2018-03-01

This is an idiosyncratic colloquium-style review of the idea that spacetime and gravity can emerge from entanglement. Drawing inspiration from the conjectured duality between quantum gravity in anti de Sitter space and certain conformal field theories, we argue that tensor networks can be used to define a discrete geometry that encodes entanglement geometrically. With the additional assumption that a continuum limit can be taken, the resulting geometry necessarily obeys Einstein's equations. The discussion takes the point of view that the emergence of spacetime and gravity is a mysterious phenomenon of quantum many-body physics that we would like to understand. We also briefly discuss possible experiments to detect emergent gravity in highly entangled quantum systems.

Estimation of arterial baroreflex sensitivity in relation to carotid artery stiffness.

PubMed

Lipponen, Jukka A; Tarvainen, Mika P; Laitinen, Tomi; Karjalainen, Pasi A; Vanninen, Joonas; Koponen, Timo; Lyyra-Laitinen, Tiina

2012-01-01

Arterial baroreflex has a significant role in regulating blood pressure. It is known that increased stiffness of the carotid sinus affects mecanotransduction of baroreceptors and therefore limits baroreceptors capability to detect changes in blood pressure. By using high resolution ultrasound video signal and continuous measurement of electrocardiogram (ECG) and blood pressure, it is possible to define elastic properties of artery simultaneously with baroreflex sensitivity parameters. In this paper dataset which consist 38 subjects, 11 diabetics and 27 healthy controls was analyzed. Use of diabetic and healthy test subjects gives wide scale of arteries with different elasticity properties, which provide opportunity to validate baroreflex and artery stiffness estimation methods.

X-ray and Optical Observations of NGC 1788

NASA Astrophysics Data System (ADS)

Alcalá, J. M.; Covino, E.; Wachter, S.; Hoard, D. W.; Sterzik, M. F.; Durisen, R. H.; Freyberg, M.; Cooksey, K.

We report on the results of ROSAT High Resolution Imager (HRI) X-ray observations and optical wide-field spectroscopy and imaging in the star forming region NGC 1788. Several new low mass pre-main sequence (PMS) stars have been found based on intermediate resolution spectroscopy. Many new PMS candidate members of NGC 1788 are selected using the spectroscopically confirmed PMS stars to define the PMS locus in color-magnitude diagrams. Some objects with very red colors detected just above the limiting magnitude of our images, are good candidates for young Brown Dwarfs (BDs). The BD nature of these objects need to be confirmed with subsequent IR observations.

Auroral-particle precipitation and trapping caused by electrostatic double layers in the ionosphere.

PubMed

Albert, R D; Lindstrom, P J

1970-12-25

Interpretation of high-resolution angular distribution measurements of the primary auroral electron flux detected by a rocket probe launched into a visible aurora from Fort Churchill in the fall of 1966 leads to the following conclusions. The auroral electron flux is nearly monoenergetic and has a quasi-trapped as well as a precipitating component. The quasi-trapped flux appears to be limited to a region defined by magnetic-mirror points and multiple electrostatic double layers in the ionosphere. The electrostatic field of the double-layer distribution enhances the aurora by lowering the magnetic-mirror points and supplying energy to the primary auroral electrons.

Arsenic contamination of drinking water in Ireland: A spatial analysis of occurrence and potential risk.

PubMed

McGrory, Ellen R; Brown, Colin; Bargary, Norma; Williams, Natalya Hunter; Mannix, Anthony; Zhang, Chaosheng; Henry, Tiernan; Daly, Eve; Nicholas, Sarah; Petrunic, Barbara M; Lee, Monica; Morrison, Liam

2017-02-01

The presence of arsenic in groundwater has become a global concern due to the health risks from drinking water with elevated concentrations. The Water Framework Directive (WFD) of the European Union calls for drinking water risk assessment for member states. The present study amalgamates readily available national and sub-national scale datasets on arsenic in groundwater in the Republic of Ireland. However, due to the presence of high levels of left censoring (i.e. arsenic values below an analytical detection limit) and changes in detection limits over time, the application of conventional statistical methods would inhibit the generation of meaningful results. In order to handle these issues several arsenic databases were integrated and the data modelled using statistical methods appropriate for non-detect data. In addition, geostatistical methods were used to assess principal risk components of elevated arsenic related to lithology, aquifer type and groundwater vulnerability. Geographic statistical methods were used to overcome some of the geographical limitations of the Irish Environmental Protection Agency (EPA) sample database. Nearest-neighbour inverse distance weighting (IDW) and local indicator of spatial association (LISA) methods were used to estimate risk in non-sampled areas. Significant differences were also noted between different aquifer lithologies, indicating that Rhyolite, Sandstone and Shale (Greywackes), and Impure Limestone potentially presented a greater risk of elevated arsenic in groundwaters. Significant differences also occurred among aquifer types with poorly productive aquifers, locally important fractured bedrock aquifers and regionally important fissured bedrock aquifers presenting the highest potential risk of elevated arsenic. No significant differences were detected among different groundwater vulnerability groups as defined by the Geological Survey of Ireland. This research will assist management and future policy directions of groundwater resources at EU level and guide future research focused on understanding arsenic mobilisation processes to facilitate in guiding future development, testing and treatment requirements of groundwater resources. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection of the aerolysin gene in Aeromonas hydrophila by the polymerase chain reaction.

PubMed Central

Pollard, D R; Johnson, W M; Lior, H; Tyler, S D; Rozee, K R

1990-01-01

Synthetic oligonucleotide primers were used in a polymerase chain reaction (PCR) technique to detect the gene for aerolysin in strains of Aeromonas hydrophila and to screen for identical genes in A. caviae, A. sobria, and A. veronii isolated from patients with diarrheal disease. Primers targeted a 209-bp fragment of the aer gene coding for the beta-hemolysin and detected template DNA only in the PCR using nucleic acid (NA) from hemolytic strains of A. hydrophila which were also cytotoxic to Vero and CHO cells and enterotoxic in suckling-mouse assays. PCR amplification of NA from hemolytic A. sobria or nonhemolytic A. hydrophila and A. caviae strains was consistently negative. Primer specificity was determined in the PCR by using NA extracted from 56 strains of bacteria, including hemolytic Escherichia coli and Listeria monocytogenes as well as several recognized enteric pathogens defined in terms of their toxigenicity. The detection limit for the aerolysin gene by PCR amplification was 1 ng of total NA. The PCR clearly identified aerolysin-producing strains of A. hydrophila and may have application as a species-specific virulence test because other hemolytic Aeromonas species tested were negative. Images PMID:2254423

Automatic building detection based on Purposive FastICA (PFICA) algorithm using monocular high resolution Google Earth images

NASA Astrophysics Data System (ADS)

Ghaffarian, Saman; Ghaffarian, Salar

2014-11-01

This paper proposes an improved FastICA model named as Purposive FastICA (PFICA) with initializing by a simple color space transformation and a novel masking approach to automatically detect buildings from high resolution Google Earth imagery. ICA and FastICA algorithms are defined as Blind Source Separation (BSS) techniques for unmixing source signals using the reference data sets. In order to overcome the limitations of the ICA and FastICA algorithms and make them purposeful, we developed a novel method involving three main steps: 1-Improving the FastICA algorithm using Moore-Penrose pseudo inverse matrix model, 2-Automated seeding of the PFICA algorithm based on LUV color space and proposed simple rules to split image into three regions; shadow + vegetation, baresoil + roads and buildings, respectively, 3-Masking out the final building detection results from PFICA outputs utilizing the K-means clustering algorithm with two number of clusters and conducting simple morphological operations to remove noises. Evaluation of the results illustrates that buildings detected from dense and suburban districts with divers characteristics and color combinations using our proposed method have 88.6% and 85.5% overall pixel-based and object-based precision performances, respectively.

Color object detection using spatial-color joint probability functions.

PubMed

Luo, Jiebo; Crandall, David

2006-06-01

Object detection in unconstrained images is an important image understanding problem with many potential applications. There has been little success in creating a single algorithm that can detect arbitrary objects in unconstrained images; instead, algorithms typically must be customized for each specific object. Consequently, it typically requires a large number of exemplars (for rigid objects) or a large amount of human intuition (for nonrigid objects) to develop a robust algorithm. We present a robust algorithm designed to detect a class of compound color objects given a single model image. A compound color object is defined as having a set of multiple, particular colors arranged spatially in a particular way, including flags, logos, cartoon characters, people in uniforms, etc. Our approach is based on a particular type of spatial-color joint probability function called the color edge co-occurrence histogram. In addition, our algorithm employs perceptual color naming to handle color variation, and prescreening to limit the search scope (i.e., size and location) for the object. Experimental results demonstrated that the proposed algorithm is insensitive to object rotation, scaling, partial occlusion, and folding, outperforming a closely related algorithm based on color co-occurrence histograms by a decisive margin.

Ship heading and velocity analysis by wake detection in SAR images

NASA Astrophysics Data System (ADS)

Graziano, Maria Daniela; D'Errico, Marco; Rufino, Giancarlo

2016-11-01

With the aim of ship-route estimation, a wake detection method is developed and applied to COSMO/SkyMed and TerraSAR-X Stripmap SAR images over the Gulf of Naples, Italy. In order to mitigate the intrinsic limitations of the threshold logic, the algorithm identifies the wake features according to the hydrodynamic theory. A post-detection validation phase is performed to classify the features as real wake structures by means of merit indexes defined in the intensity domain. After wake reconstruction, ship heading is evaluated on the basis of turbulent wake direction and ship velocity is estimated by both techniques of azimuth shift and Kelvin pattern wavelength. The method is tested over 34 ship wakes identified by visual inspection in both HH and VV images at different incidence angles. For all wakes, no missed detections are reported and at least the turbulent and one narrow-V wakes are correctly identified, with ship heading successfully estimated. Also, the azimuth shift method is applied to estimate velocity for the 10 ships having route with sufficient angular separation from the satellite ground track. In one case ship velocity is successfully estimated with both methods, showing agreement within 14%.

Detecting spatial regimes in ecosystems | Science Inventory ...

EPA Pesticide Factsheets

Research on early warning indicators has generally focused on assessing temporal transitions with limited application of these methods to detecting spatial regimes. Traditional spatial boundary detection procedures that result in ecoregion maps are typically based on ecological potential (i.e. potential vegetation), and often fail to account for ongoing changes due to stressors such as land use change and climate change and their effects on plant and animal communities. We use Fisher information, an information theory based method, on both terrestrial and aquatic animal data (US Breeding Bird Survey and marine zooplankton) to identify ecological boundaries, and compare our results to traditional early warning indicators, conventional ecoregion maps, and multivariate analysis such as nMDS (non-metric Multidimensional Scaling) and cluster analysis. We successfully detect spatial regimes and transitions in both terrestrial and aquatic systems using Fisher information. Furthermore, Fisher information provided explicit spatial information about community change that is absent from other multivariate approaches. Our results suggest that defining spatial regimes based on animal communities may better reflect ecological reality than do traditional ecoregion maps, especially in our current era of rapid and unpredictable ecological change. Use an information theory based method to identify ecological boundaries and compare our results to traditional early warning

Rapid, highly sensitive detection of herpes simplex virus-1 using multiple antigenic peptide-coated superparamagnetic beads.

PubMed

Ran, Ying-Fen; Fields, Conor; Muzard, Julien; Liauchuk, Viktoryia; Carr, Michael; Hall, William; Lee, Gil U

2014-12-07

A sensitive, rapid, and label free magnetic bead aggregation (MBA) assay has been developed that employs superparamagnetic (SPM) beads to capture, purify, and detect model proteins and the herpes simplex virus (HSV). The MBA assay is based on monitoring the aggregation state of a population of SPM beads using light scattering of individual aggregates. A biotin-streptavidin MBA assay had a femtomolar (fM) level sensitivity for analysis times less than 10 minutes, but the response of the assay becomes nonlinear at high analyte concentrations. A MBA assay for the detection of HSV-1 based on a novel peptide probe resulted in the selective detection of the virus at concentrations as low as 200 viral particles (vp) per mL in less than 30 min. We define the parameters that determine the sensitivity and response of the MBA assay, and the mechanism of enhanced sensitivity of the assay for HSV. The speed, relatively low cost, and ease of application of the MBA assay promise to make it useful for the identification of viral load in resource-limited and point-of-care settings where molecular diagnostics cannot be easily implemented.

Non-invasive genetic sampling of Southern Mule Deer (Odocoileus hemionus fuliginatus) reveals limited movement across California State Route 67 in San Diego County

USGS Publications Warehouse

Mitelberg, Anna; Vandergast, Amy

2016-01-01

—The Southern Mule Deer is a mobile but non-migratory large mammal found throughout southern California and is a covered species in the San Diego Multi-Species Conservation Plan. We assessed deer movement and population connectivity across California State Route 67 and two smaller roads in eastern San Diego County using non-invasive genetic sampling. We collected deer scat pellets between April and November 2015, and genotyped pellets at 15 microsatellites and a sex determination marker. We successfully genotyped 71 unique individuals from throughout the study area and detected nine recapture events. Recaptures were generally found close to original capture locations (within 1.5 km). We did not detect recaptures across roads; however, pedigree analysis detected 21 first order relative pairs, of which approximately 20% were found across State Route 67. Exact tests comparing allele frequencies between groups of individuals in pre-defined geographic clusters detected significant genetic differentiation across State Route 67. In contrast, the assignment-based algorithm of STRUCTURE supported a single genetic cluster across the study area. Our data suggest that State Route 67 may reduce, but does not preclude, movement and gene flow of Southern Mule Deer.

Ultrasensitive and rapid detection of β-conglutin combining aptamers and isothermal recombinase polymerase amplification.

PubMed

Jauset-Rubio, Miriam; Sabaté Del Río, Jonathan; Mairal, Teresa; Svobodová, Markéta; El-Shahawi, Mohammad S; Bashammakh, Abdulaziz S; Alyoubi, Abdulrahman O; O'Sullivan, Ciara K

2017-01-01

Lupin is increasingly being used in a variety of food products due to its nutritional, functional and nutraceutical properties. However, several examples of severe and even fatal food-associated anaphylaxis due to lupin inhalation or ingestion have been reported, resulting in the lupin subunit β-conglutin, being defined as the Lup an 1 allergen by the International Union of Immunological Societies (IUIS) in 2008. Here, we report an innovative method termed aptamer-recombinase polymerase amplification (Apta-RPA) exploiting the affinity and specificity of a DNA aptamer selected against the anaphylactic β-conglutin allergen termed β-conglutin binding aptamer II (β-CBA II), facilitating ultrasensitive detection via isothermal amplification. Combining magnetic beads as the solid phase with Apta-RPA detection, the total assay time was reduced from 210 min to just 25 min, with a limit of detection of 3.5 × 10 -11  M, demonstrating a rapid and ultrasensitive generic methodology that can be used with any aptamer. Future work will focus on further simplification of the assay to a lateral flow format. Graphical Abstract Schematic representation of the rapid and novel bead-based Apta-RPA assay.

Limitations of malaria reactive case detection in an area of low and unstable transmission on the Myanmar-Thailand border.

PubMed

Parker, Daniel M; Landier, Jordi; von Seidlein, Lorenz; Dondorp, Arjen; White, Lisa; Hanboonkunupakarn, Borimas; Maude, Richard J; Nosten, François H

2016-11-25

Reactive case detection is an approach that has been proposed as a tool for malaria elimination in low-transmission settings. It is an intuitively justified approach based on the concept of space-time clustering of malaria cases. When an index malaria clinical case is detected, it triggers reactive screening and treatment in the index house and neighbouring houses. However, the efficacy of this approach at varying screening radii and malaria prevalence remains ill defined. Data were obtained from a detailed demographic and geographic surveillance study in four villages on the Myanmar-Thailand border. Clinical cases were recorded at village malaria clinics and were linked back to patients' residencies. These data were used to simulate the efficacy of reactive case detection for clinical cases using rapid diagnostic tests (RDT). Simulations took clinical cases in a given month and tabulated the number of cases that would have been detected in the following month at varying screening radii around the index houses. Simulations were run independently for both falciparum and vivax malaria. Each simulation of a reactive case detection effort was run in comparison with a strategy using random selection of houses for screening. In approximately half of the screenings for falciparum and 10% for vivax it would have been impossible to detect any malaria cases regardless of the screening strategy because the screening would have occurred during times when there were no cases. When geographically linked cases were present in the simulation, reactive case detection would have only been successful at detecting most malaria cases using larger screening radii (150-m radius and above). At this screening radius and above, reactive case detection does not perform better than random screening of an equal number of houses in the village. Screening within very small radii detects only a very small proportion of cases, but despite this low performance is better than random screening with the same sample size. The results of these simulations indicate that reactive case detection for clinical cases using RDTs has limited ability in halting transmission in regions of low and unstable transmission. This is linked to high spatial heterogeneity of cases, acquisition of malaria infections outside the village, as well missing asymptomatic infections. When cases are few and sporadic, reactive case detection would result in major time and budgetary losses.

Enhanced Reverse Transcription-PCR Assay for Detection of Norovirus Genogroup I

PubMed Central

Dreier, Jens; Störmer, Melanie; Mäde, Dietrich; Burkhardt, Sabine; Kleesiek, Knut

2006-01-01

We have developed a one-tube reverse transcription (RT)-PCR method using the real-time TaqMan PCR system for the detection of norovirus genogroup I (NV GGI). By introduction of a novel probe based on locked nucleic acid technology, we enhanced the sensitivity of the assay compared to those of conventional TaqMan probes. The sensitivity of the NV GGI RT-PCR was determined by probit analysis with defined RNA standards and quantified norovirus isolates to 711 copies/ml (95% detection limit). In order to detect PCR inhibition, we included a heterologous internal control (IC) system based on phage MS2. This internally controlled RT-PCR was tested on different real-time PCR platforms, LightCycler, Rotorgene, Mastercycler EP realplex, and ABI Prism. Compared to the assay without an IC, the duplex RT-PCR exhibited no reduction in sensitivity in clinical samples. In combination with an established NV GGII real-time RT-PCR, we used the novel assay in a routine assay for diagnosis of clinical and food-borne norovirus infection. We applied this novel assay to analyze outbreaks of nonbacterial acute gastroenteritis. Norovirus of GGI was detected in these outbreaks. Sequence and similarity plot analysis of open reading frame 1 (ORF1) and ORF2 showed two genotypes, GGI/2 and GGI/4, in semiclosed communities. PMID:16891482

Functional magnetic resonance imaging activation detection: fuzzy cluster analysis in wavelet and multiwavelet domains.

PubMed

Jahanian, Hesamoddin; Soltanian-Zadeh, Hamid; Hossein-Zadeh, Gholam-Ali

2005-09-01

To present novel feature spaces, based on multiscale decompositions obtained by scalar wavelet and multiwavelet transforms, to remedy problems associated with high dimension of functional magnetic resonance imaging (fMRI) time series (when they are used directly in clustering algorithms) and their poor signal-to-noise ratio (SNR) that limits accurate classification of fMRI time series according to their activation contents. Using randomization, the proposed method finds wavelet/multiwavelet coefficients that represent the activation content of fMRI time series and combines them to define new feature spaces. Using simulated and experimental fMRI data sets, the proposed feature spaces are compared to the cross-correlation (CC) feature space and their performances are evaluated. In these studies, the false positive detection rate is controlled using randomization. To compare different methods, several points of the receiver operating characteristics (ROC) curves, using simulated data, are estimated and compared. The proposed features suppress the effects of confounding signals and improve activation detection sensitivity. Experimental results show improved sensitivity and robustness of the proposed method compared to the conventional CC analysis. More accurate and sensitive activation detection can be achieved using the proposed feature spaces compared to CC feature space. Multiwavelet features show superior detection sensitivity compared to the scalar wavelet features. (c) 2005 Wiley-Liss, Inc.

Enhanced solid-phase recombinase polymerase amplification and electrochemical detection.

PubMed

Del Río, Jonathan Sabaté; Lobato, Ivan Magriñà; Mayboroda, Olena; Katakis, Ioanis; O'Sullivan, Ciara K

2017-05-01

Recombinase polymerase amplification (RPA) is an elegant method for the rapid, isothermal amplification of nucleic acids. Here, we elucidate the optimal surface chemistry for rapid and efficient solid-phase RPA, which was fine-tuned in order to obtain a maximum signal-to-noise ratio, defining the optimal DNA probe density, probe-to-lateral spacer ratio (1:0, 1:1, 1:10 and 1:100) and length of a vertical spacer of the probe as well as investigating the effect of different types of lateral spacers. The use of different labelling strategies was also examined in order to reduce the number of steps required for the analysis, using biotin or horseradish peroxidase-labelled reverse primers. Optimisation of the amplification temperature used and the use of surface blocking agents were also pursued. The combination of these changes facilitated a significantly more rapid amplification and detection protocol, with a lowered limit of detection (LOD) of 1 · 10 -15 M. The optimised protocol was applied to the detection of Francisella tularensis in real samples from hares and a clear correlation with PCR and qPCR results observed and the solid-phase RPA demonstrated to be capable of detecting 500 fM target DNA in real samples. Graphical abstract Relative size of thiolated lateral spacers tested versus the primer and the uvsx recombinase protein.

Nondestructive tests of regenerative chambers. [evaluating nondestructive methods of determining metal bond integrity

NASA Technical Reports Server (NTRS)

Malone, G. A.; Vecchies, L.; Wood, R.

1974-01-01

The capabilities and limitations of nondestructive evaluation methods were studied to detect and locate bond deficiencies in regeneratively cooled thrust chambers for rocket engines. Flat test panels and a cylinder were produced to simulate regeneratively cooled thrust chamber walls. Planned defects with various bond integrities were produced in the panels to evaluate the sensitivity, accuracy, and limitations of nondestructive methods to define and locate bond anomalies. Holography, acoustic emission, and ultrasonic scan were found to yield sufficient data to discern bond quality when used in combination and in selected sequences. Bonding techniques included electroforming and brazing. Materials of construction included electroformed nickel bonded to Nickel 200 and OFHC copper, electroformed copper bonded to OFHC copper, and 300 series stainless steel brazed to OFHC copper. Variations in outer wall strength, wall thickness, and defect size were evaluated for nondestructive test response.

THE MURCHISON WIDEFIELD ARRAY 21 cm POWER SPECTRUM ANALYSIS METHODOLOGY

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

Jacobs, Daniel C.; Beardsley, A. P.; Bowman, Judd D.

2016-07-10

We present the 21 cm power spectrum analysis approach of the Murchison Widefield Array Epoch of Reionization project. In this paper, we compare the outputs of multiple pipelines for the purpose of validating statistical limits cosmological hydrogen at redshifts between 6 and 12. Multiple independent data calibration and reduction pipelines are used to make power spectrum limits on a fiducial night of data. Comparing the outputs of imaging and power spectrum stages highlights differences in calibration, foreground subtraction, and power spectrum calculation. The power spectra found using these different methods span a space defined by the various tradeoffs between speed,more » accuracy, and systematic control. Lessons learned from comparing the pipelines range from the algorithmic to the prosaically mundane; all demonstrate the many pitfalls of neglecting reproducibility. We briefly discuss the way these different methods attempt to handle the question of evaluating a significant detection in the presence of foregrounds.« less

Laser profile changes due to photon-axion induced beam splitting

NASA Astrophysics Data System (ADS)

Scarlett, Carol

2013-09-01

This paper looks at a potentially unique measurable due to photon-axion coupling in an external magnetic field. Traditionally, detection of such a coupling has focused on observation of an optical rotation of the beam's polarization due to either a birefringence or a path length difference (p.l.d.) between two polarization states. Such experiments, utilizing mirror cavities, have been significantly limited in sensitivity; approaching coupling strengths of ~ga=10-7 GeV-1. Here the bifurcation of a beam in a cavity is explored along with the possibility of measuring its influence on the photon density. Simulations indicate that coupling to levels ga~10-12 are, with an appropriate choice of cavity, within measurable limits. This is due to a rapid growth of a signal defined by the energy loss from the center accompanying an increase in the region beyond the beam waist. Finally, the influence of a non-zero axion mass is explored.

Scalable Background-Limited Polarization-Sensitive Detectors for mm-wave Applications

NASA Technical Reports Server (NTRS)

Rostem, Karwan; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Chuss, David T.; Colazo, Felipe A.; Crowe, Erik; Denis, Kevin L.; Essinger-Hileman, Tom; Marriage, Tobias A.;

High time-resolved radon progeny measurements in the Arctic region (Svalbard islands, Norway): results and potentialities

NASA Astrophysics Data System (ADS)

Salzano, Roberto; Pasini, Antonello; Ianniello, Antonietta; Mazzola, Mauro; Traversi, Rita; Udisti, Roberto

2018-05-01

The estimation of radon progeny in the Arctic region represents a scientific challenge due to the required low limit of detection in consideration of the limited radon emanation associated with permafrost dynamics. This preliminary study highlighted, for the first time above 70° N, the possibility to monitor radon progeny in the Arctic region with a higher time resolution. The composition of the radon progeny offered the opportunity to identify air masses dominated by long-range transport, in presence or absence of near-constant radon progeny instead of long- and short-lived progenies. Furthermore, the different ratio between radon and thoron progenies evidenced the contributions of local emissions and atmospheric stability. Two different emanation periods were defined in accordance with the permafrost dynamics at the ground and several accumulation windows were recognized coherently to the meteo-climatic conditions occurring at the study site.

Cytogenetics in the management of acute myeloid leukemia: an update by the Groupe francophone de cytogénétique hématologique (GFCH).

PubMed

Luquet, Isabelle; Bidet, Audrey; Cuccuini, Wendy; Lafage-Pochitaloff, Marina; Mozziconacci, Marie-Joëlle; Terré, Christine

2016-10-01

The karyotype is critical for the evaluation of acute myeloid leukemia (AML) at diagnosis. Cytogenetic abnormalities detected in AML are one of the most powerful independent prognostic factors. It impacts on the choice of treatment in clinical trials. All chromosomes can be targeted, common chromosomal abnormalities are recurrent and may be associated with a cytological well-defined type. In 40% of the cases, the karyotype is normal and must be associated with molecular biology studies that can refine the prognosis. The usefulness of the karyotype is more limited during the follow-up of the patient due to its limited sensitivity, but it is still useful in the clinical management of relapse. Since 2001, the WHO (World Health Organization) classification of hematological malignancies integrates cytogenetic data in the classification of AML. Karyotype is therefore mandatory in the diagnosis of AML.

Recommendations for palliative and bereavement care in the NICU: a family-centered integrative approach.

PubMed

Kenner, C; Press, J; Ryan, D

2015-12-01

Technological advances have increased our ability to detect a life-threatening, life-limiting or lethal problem early in pregnancy, leaving parents months to anticipate a death or a prematurely born infant. Babies can also be born with unanticipated problems that could lead to death. In either scenario, perinatal palliative care should be offered as a strategy for family support. Since the preponderance of professional training focuses on saving lives, many health professionals are uncomfortable with palliative care. This article's purpose is to define best practices for the provision of family-centered perinatal and neonatal palliative care and provision of support to bereaved families experiencing anticipated and unanticipated life-limiting conditions or death of their infant. An overview of core concepts and values is presented, followed by intervention strategies to promote an integrated family-centered approach to palliative and bereavement care. The concluding section presents evidence-based recommendations.

High sensitive THz superconducting hot electron bolometer mixers and transition edge sensors

NASA Astrophysics Data System (ADS)

Zhang, W.; Miao, W.; Zhou, K. M.; Guo, X. H.; Zhong, J. Q.; Shi, S. C.

2016-11-01

Terahertz band, which is roughly defined as 0.1 THz to 10 THz, is an interesting frequency region of the electromagnetic spectrum to be fully explored in astronomy. THz observations play key roles in astrophysics and cosmology. High sensitive heterodyne and direct detectors are the main tools for the detection of molecular spectral lines and fine atomic structure spectral lines, which are very important tracers for probing the physical and chemical properties and dynamic processes of objects such as star and planetary systems. China is planning to build an THz telescope at Dome A, Antarctica, a unique site for ground-based THz observations. We are developing THz superconducting hot electron bolometer (HEB) mixers and transition edge sensors (TES), which are quantum limited and back-ground limited detectors, respectively. Here we first introduce the working principles of superconducting HEB and TES, and then mainly present the results achieved at Purple mountain Observatory.

Defining overweight and obesity among Greek children living in Thessaloniki: International versus local reference standards.

PubMed

Christoforidis, A; Dimitriadou, M; Papadopolou, E; Stilpnopoulou, D; Katzos, G; Athanassiou-Metaxa, M

2011-04-01

Body Mass Index (BMI) offers a simple and reasonable measure of obesity that, with the use of the appropriate reference, can help in the early detection of children with weight problems. Our aim was to compare the two most commonly used international BMI references and the national Greek BMI reference in identifying Greek children being overweight and obese. A group of 1557 children (820 girls and 737 boys, mean age: 11.42 ± 3.51 years) were studied. Weight and height was measured using standard methods, and BMI was calculated. Overweight and obesity were determined using the International Obesity Task Force (IOTF) standards, the Centers for Disease Control and Prevention (CDC) BMI-forage curves and the most recent Greek BMI-for-age curves. RESULTS showed that the IOTF's cut-off limits identifies a significantly higher prevalence of overweight (22.4%) compared with both the CDC's (11.8%, p=0.03) and the Greek's (7.4%, p=0.002) cut-off limits. However, the prevalence of obesity was generally increased when it was determined using the CDC's cut-off limits (13.9%) compared to the prevalence calculated with both the IOTF's (6.5%, p=0.05) and the Greek's (6.9%, n.s.) cut off limits. The use of the national Greek reference standards for BMI underestimates the true prevalence of overweight and obesity. On the contrary, both the IOTF and the CDC standards, although independently, detect an increased number of overweight and obese children and thus they should be adopted in the clinical practice for an earlier identification and a timelier intervention.

Radio Observations of Ultra-Luminous X-Ray Sources and their Implication for Models

NASA Astrophysics Data System (ADS)

Koerding, E. G.; Colbert, E. J. M.; Falcke, H.

2004-05-01

We present the results of a radio monitoring campaign to search for radio emission from nearby ultra-luminous X-ray sources (ULXs). These intriguing sources are bright off-nuclear X-ray point sources with luminosities exceeding LX > 1039 erg/sec. Assuming isotropic emission the Eddington Limit suggests that they harbor intermediate mass black holes. Due to the problems of this explanation also other possibilities are currently discussed, among them are anisotropic emission, super-Eddington accretion flows or relativistically beamed emission from microquasars. Detections of compact radio cores at the positions of ULXs would be a direct hint to jet-emission. However, as the ULX phenomenom is connected to star formation we have to assume that they are strongly accreting objects. Thus, similar to their nearest Galactic cousins, the very high state X-ray binaries (see e.g., GRS 1915), ULXs may show radio flares. A well-defined sample of the 9 nearest ULXs has been monitored eight times during 5 months with the Very Large Array in A and B configuration. Our limiting sensitivity is 0.15 mJy (4 σ ) for flares and 68 μ Jy for continuous emission. In M82 some ULXs seem to be connected to radio supernova remnants. Besides that no flare or continuous emission has been detected. As the timescales of radio flares in ULXs are highly uncertain, it could well be that we have undersampled the lightcurve. However, upper bounds for the probability to detect a flare can be given. The upper limits for the continuous emission are compared with the emission found in NGC 5408 X-1 and with quasars and microquasars. We show that these limits are well in agreement with the microblazar model using the Radio/X-ray correlation of XRBs and AGN. Thus, it could well be that ULXs are microblazers which may be radio loud.

Device and method for screening crystallization conditions in solution crystal growth

NASA Technical Reports Server (NTRS)

Carter, Daniel C. (Inventor)

1995-01-01

A device and method for detecting optimum protein crystallization conditions and for growing protein crystals in either 1g or microgravity environments comprising a housing, defining at least one pair of chambers for containing crystallization solutions is presented. The housing further defines an orifice therein for providing fluid communication between the chambers. The orifice is adapted to receive a tube which contains a gelling substance for limiting the rate of diffusive mixing of the crystallization solutions. The solutions are diffusively mixed over a period of time defined by the quantity of gelling substance sufficient to achieve equilibration and to substantially reduce density driven convection disturbances therein. The device further includes endcaps to seal the first and second chambers. One of the endcaps includes a dialysis chamber which contains protein solution in which protein crystals are grown. Once the endcaps are in place, the protein solution is exposed to the crystallization solutions wherein the solubility of the protein solution is reduced at a rate responsive to the rate of diffusive mixing of the crystallization solutions. This allows for a controlled approach to supersaturation and allows for screening of crystal growth conditions at preselected intervals.

Device and Method for Screening Crystallization Conditions in Solution Crystal Growth

NASA Technical Reports Server (NTRS)

Carter, Daniel C. (Inventor)

1997-01-01

A device and method for detecting optimum protein crystallization conditions and for growing protein crystals in either 1 g or microgravity environments comprising a housing defining at least one pair of chambers for containing crystallization solutions. The housing further defines an orifice therein for providing fluid communication between the chambers. The orifice is adapted to receive a tube which contains a gelling substance for limiting the rate of diffusive mixing of the crystallization solutions. The solutions are diffusively mixed over a period of time defined by the quantity of gelling substance sufficient to achieve equilibration and to substantially reduce density driven convection disturbances therein. The device further includes endcaps to seal the first and second chambers. One of the endcaps includes a dialysis chamber which contains protein solution in which protein crystals are grown. Once the endcaps are in place. the protein solution is exposed to the crystallization solutions wherein the solubility of the protein solution is reduced at a rate responsive to the rate of diffusive mixing of the crystallization solutions. This allows for a controlled approach to supersaturation and allows for screening of crystal growth conditions at preselected intervals.

40 CFR Appendix B to Part 136 - Definition and Procedure for the Determination of the Method Detection Limit-Revision 1.11

Code of Federal Regulations, 2010 CFR

2010-07-01

... calculated method detection limit. To insure that the estimate of the method detection limit is a good...) where: MDL = the method detection limit t(n-1,1- α=.99) = the students' t value appropriate for a 99... Determination of the Method Detection Limit-Revision 1.11 B Appendix B to Part 136 Protection of Environment...

Material limitations on the detection limit in refractometry.

PubMed

Skafte-Pedersen, Peder; Nunes, Pedro S; Xiao, Sanshui; Mortensen, Niels Asger

2009-01-01

We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

Comparison of cyclic correlation and the wavelet method for symbol rate detection

NASA Astrophysics Data System (ADS)

Carr, Richard; Whitney, James

Software defined radio (SDR) is a relatively new technology that holds a great deal of promise in the communication field in general, and, in particular the area of space communications. Tra-ditional communication systems are comprised of a transmitter and a receiver, where through prior planning and scheduling, the transmitter and receiver are pre-configured for a particu-lar communication modality. For any particular modality the radio circuitry is configured to transmit, receive, and resolve one type of modulation at a certain data rate. Traditional radio's are limited by the fact that the circuitry is fixed. Software defined radios on the other hand do not suffer from this limitation. SDR's are comprised mainly of software modules which allow them to be flexible, in that they can resolve various types of modulation types that occur at different data rates. This ability is of very high importance in space where parameters of the communications link may need to be changed due to channel fading, reduced power, or other unforeseen events. In these cases the ability to autonomously change aspects of the radio's con-figuration becomes an absolute necessity in order to maintain communications. In order for the technology to work the receiver has to be able to determine the modulation type and the data rate of the signal. The data rate of the signal is one of the first parameters to be resolved, as it is needed to find the other signal parameters such as modulation type and the signal-to-noise ratio. There are a number of algorithms that have been developed to detect or estimate the data rate of a signal. This paper will investigate two of these algorithms, namely, the cyclic correlation algorithm and a wavelet-based detection algorithm. Both of these algorithms are feature-based algorithms, meaning that they make their estimations based on certain inherent features of the signals to which they are applied. The cyclic correlation algorithm takes advan-tage of the cyclostationary nature of MPSK signals, while the wavelet-based algorithms take advantage of the fact of being able to detect transient changes in the signal, i.e., transitions from `1' to'0'. Both of these algorithms are tested under various signal-to-noise conditions to see which has the better performance, and the results are presented in this paper.

PanCoreGen - Profiling, detecting, annotating protein-coding genes in microbial genomes.

PubMed

Paul, Sandip; Bhardwaj, Archana; Bag, Sumit K; Sokurenko, Evgeni V; Chattopadhyay, Sujay

2015-12-01

A large amount of genomic data, especially from multiple isolates of a single species, has opened new vistas for microbial genomics analysis. Analyzing the pan-genome (i.e. the sum of genetic repertoire) of microbial species is crucial in understanding the dynamics of molecular evolution, where virulence evolution is of major interest. Here we present PanCoreGen - a standalone application for pan- and core-genomic profiling of microbial protein-coding genes. PanCoreGen overcomes key limitations of the existing pan-genomic analysis tools, and develops an integrated annotation-structure for a species-specific pan-genomic profile. It provides important new features for annotating draft genomes/contigs and detecting unidentified genes in annotated genomes. It also generates user-defined group-specific datasets within the pan-genome. Interestingly, analyzing an example-set of Salmonella genomes, we detect potential footprints of adaptive convergence of horizontally transferred genes in two human-restricted pathogenic serovars - Typhi and Paratyphi A. Overall, PanCoreGen represents a state-of-the-art tool for microbial phylogenomics and pathogenomics study. Copyright © 2015 Elsevier Inc. All rights reserved.

Validation of an UHPLC-MS/MS Method for Screening of Antimicrobial Residues in Eggs and Their Application to Analyses of Eggs from Laying Hens Subjected to Pharmacological Treatment

PubMed Central

Caldeira, Letícia Gomes Magnago; Santos, Flávio Alves; de Oliveira, Andréa Melo Garcia; Lima, Josefa Abucater; de Souza, Leonardo Francisco; da Silva, Guilherme Resende; de Assis, Débora Cristina Sampaio

2017-01-01

A multiresidue method by UHPLC/MS-MS was optimized and validated for the screening and semiquantitative detection of antimicrobials residues from tetracyclines, aminoglycosides, quinolones, lincosamides, β-lactams, sulfonamides, and macrolides families in eggs. A qualitative approach was used to ensure adequate sensitivity to detect residues at the level of interest, defined as maximum residue limit (MRL), or less. The applicability of the methods was assessed by analyzing egg samples from hens that had been subjected to pharmacological treatment with neomycin, enrofloxacin, lincomycin, oxytetracycline, and doxycycline during five days and after discontinuation of medication (10 days). The method was adequate for screening all studied analytes in eggs, since the performance parameters ensured a false-compliant rate below or equal to 5%, except for flumequine. In the analyses of eggs from laying hens subjected to pharmacological treatment, all antimicrobial residues were detected throughout the experimental period, even after discontinuation of medication, except for neomycin, demonstrating the applicability of the method for analyses of antimicrobial residues in eggs. PMID:29181222

Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators

PubMed Central

Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François

2017-01-01

Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila. These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision. DOI: http://dx.doi.org/10.7554/eLife.25690.001 PMID:28749338

Nanocolloidal gold-based immuno-dip strip assay for rapid detection of Sudan red I in food samples.

PubMed

Wang, Jia; Wang, Zhanhui; Liu, Jing; Li, Hao; Li, Qing X; Li, Ji; Xu, Ting

2013-02-15

A semiquantitative dip strip assay was developed using nanocolloidal gold-labelled monoclonal antibody (Mab) 8A10 for the rapid detection of Sudan red I in food samples. A protein-Sudan red I conjugate was coated on a nitro cellulose membrane strip in a defined test line. In flow of the complex of nanocolloidal gold labelled-Mab and Sudan red I along the strip, intensive red colour that was formed in the test line reflected the Sudan red I concentration. The test required 10 min and had a visual limit of detection of 10 ng/g Sudan red I in tomato sauce and chilli powder samples. The results of the strip assay agreed well with those of a high performance liquid chromatography method for both spiked and real commercial samples. The strip was stable for at least 2 months at 4°C. The strip assay offers the potential as a useful rapid and simple method for screening of Sudan red I in food samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

Defining the minimal detectable change in scores on the eight-item Morisky Medication Adherence Scale.

PubMed

Muntner, Paul; Joyce, Cara; Holt, Elizabeth; He, Jiang; Morisky, Donald; Webber, Larry S; Krousel-Wood, Marie

2011-05-01

Self-report scales are used to assess medication adherence. Data on how to discriminate change in self-reported adherence over time from random variability are limited. To determine the minimal detectable change for scores on the 8-item Morisky Medication Adherence Scale (MMAS-8). The MMAS-8 was administered twice, using a standard telephone script, with administration separated by 14-22 days, to 210 participants taking antihypertensive medication in the CoSMO (Cohort Study of Medication Adherence among Older Adults). MMAS-8 scores were calculated and participants were grouped into previously defined categories (<6, 6 to <8, and 8 for low, medium, and high adherence). The mean (SD) age of participants was 78.1 (5.8) years, 43.8% were black, and 68.1% were women. Overall, 8.1% (17/210), 16.2% (34/210), and 51.0% (107/210) of participants had low, medium, and high MMAS-8 scores, respectively, at both survey administrations (overall agreement 75.2%; 158/210). The weighted κ statistic was 0.63 (95% CI 0.53 to 0.72). The intraclass correlation coefficient was 0.78. The within-person standard error of the mean for change in MMAS-8 scores was 0.81, which equated to a minimal detectable change of 1.98 points. Only 4.3% (9/210) of the participants had a change in MMAS-8 of 2 or more points between survey administrations. Within-person changes in MMAS-8 scores of 2 or more points over time may represent a real change in antihypertensive medication adherence.

Low-Cost, Disposable, Flexible and Highly Reproducible Screen Printed SERS Substrates for the Detection of Various Chemicals

PubMed Central

Wu, Wei; Liu, Li; Dai, Zhigao; Liu, Juhua; Yang, Shuanglei; Zhou, Li; Xiao, Xiangheng; Jiang, Changzhong; Roy, Vellaisamy A.L.

2015-01-01

Ideal SERS substrates for sensing applications should exhibit strong signal enhancement, generate a reproducible and uniform response, and should be able to fabricate in large-scale and low-cost. Herein, we demonstrate low-cost, highly sensitive, disposable and reproducible SERS substrates by means of screen printing Ag nanoparticles (NPs) on a plastic PET (Polyethylene terephthalate) substrates. While there are many complex methods for the fabrication of SERS substrates, screen printing is suitable for large-area fabrication and overcomes the uneven radial distribution. Using as-printed Ag substrates as the SERS platform, detection of various commonly known chemicals have been done. The SERS detection limit of Rhodamine 6G (R6G) is higher than the concentration of 1 × 10−10 M. The relative standard deviation (RSD) value for 784 points on the detection of R6G and Malachite green (MG) is less than 20% revealing a homogeneous SERS distribution and high reproducibility. Moreover, melamine (MA) is detected in fresh liquid-milk without additional pretreatment, which may accelerate the application of rapid on-line detection of MA in liquid milk. Our screen printing method highlights the use of large-scale printing strategies for the fabrication of well-defined functional nanostructures with applications well beyond the field of SERS sensing. PMID:25974125

A New Approach to Defining Human Touch Temperature Standards

NASA Technical Reports Server (NTRS)

Ungar, Eugene; Stroud, Kenneth

2010-01-01

Defining touch temperature limits for skin contact with both hot and cold objects is important to prevent pain and skin damage, which may affect task performance or become a safety concern. Pain and skin damage depend on the skin temperature during contact, which depends on the contact thermal conductance, the object's initial temperature, and its material properties. However, previous spacecraft standards have incorrectly defined touch temperature limits in terms of a single object temperature value for all materials, or have provided limited material-specific values which do not cover the gamut of likely designs. A new approach has been developed for updated NASA standards, which defines touch temperature limits in terms of skin temperature at pain onset for bare skin contact with hot and cold objects. The authors have developed an analytical verification method for safe hot and cold object temperatures for contact times from 1 second to infinity.

A New Approach to Defining Human Touch Temperature Standards

NASA Technical Reports Server (NTRS)

Ungar, Eugene; Stroud, Kenneth

2009-01-01

Defining touch temperature limits for skin contact with both hot and cold objects is important to prevent pain and skin damage, which may affect task performance or become a safety concern. Pain and skin damage depend on the resulting skin temperature during contact, which depends on the object s initial temperature, its material properties and its ability to transfer heat. However, previous spacecraft standards have incorrectly defined touch temperature limits in terms of a single object temperature value for all materials, or have provided limited material-specific values which do not cover the gamut of most designs. A new approach is being used in new NASA standards, which defines touch temperature limits in terms of skin temperature at pain onset for bare skin contact with hot and cold objects. The authors have developed an analytical verification method for safe hot and cold object temperatures for contact times from 1 second to infinity.

Imaging free radicals in organelles, cells, tissue, and in vivo with immuno-spin trapping.

PubMed

Mason, Ronald Paul

2016-08-01

The accurate and sensitive detection of biological free radicals in a reliable manner is required to define the mechanistic roles of such species in biochemistry, medicine and toxicology. Most of the techniques currently available are either not appropriate to detect free radicals in cells and tissues due to sensitivity limitations (electron spin resonance, ESR) or subject to artifacts that make the validity of the results questionable (fluorescent probe-based analysis). The development of the immuno-spin trapping technique overcomes all these difficulties. This technique is based on the reaction of amino acid- and DNA base-derived radicals with the spin trap 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) to form protein- and DNA-DMPO nitroxide radical adducts, respectively. These adducts have limited stability and decay to produce the very stable macromolecule-DMPO-nitrone product. This stable product can be detected by mass spectrometry, NMR or immunochemistry by the use of anti-DMPO nitrone antibodies. The formation of macromolecule-DMPO-nitrone adducts is based on the selective reaction of free radical addition to the spin trap and is thus not subject to artifacts frequently encountered with other methods for free radical detection. The selectivity of spin trapping for free radicals in biological systems has been proven by ESR. Immuno-spin trapping is proving to be a potent, sensitive (a million times higher sensitivity than ESR), and easy (not quantum mechanical) method to detect low levels of macromolecule-derived radicals produced in vitro and in vivo. Anti-DMPO antibodies have been used to determine the distribution of free radicals in cells and tissues and even in living animals. In summary, the invention of the immuno-spin trapping technique has had a major impact on the ability to accurately and sensitively detect biological free radicals and, subsequently, on our understanding of the role of free radicals in biochemistry, medicine and toxicology. Published by Elsevier B.V.

Material Limitations on the Detection Limit in Refractometry

PubMed Central

Skafte-Pedersen, Peder; Nunes, Pedro S.; Xiao, Sanshui; Mortensen, Niels Asger

2009-01-01

We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly. PMID:22291513

Estimation of pyrethroid pesticide intake using regression ...

EPA Pesticide Factsheets

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation of pesticide intakes for a defined demographic community, and (2) comparison of dietary pesticide intakes between the composite and individual samples. Extant databases were useful for assigning individual samples to composites, but they could not provide the breadth of information needed to facilitate measurable levels in every composite. Composite sample measurements were found to be good predictors of pyrethroid pesticide levels in their individual sample constituents where sufficient measurements are available above the method detection limit. Statistical inference shows little evidence of differences between individual and composite measurements and suggests that regression modeling of food groups based on composite dietary samples may provide an effective tool for estimating dietary pesticide intake for a defined population. The research presented in the journal article will improve community's ability to determine exposures through the dietary route with a less burdensome and costly method.

Generalized Detectability for Discrete Event Systems

PubMed Central

Shu, Shaolong; Lin, Feng

2011-01-01

In our previous work, we investigated detectability of discrete event systems, which is defined as the ability to determine the current and subsequent states of a system based on observation. For different applications, we defined four types of detectabilities: (weak) detectability, strong detectability, (weak) periodic detectability, and strong periodic detectability. In this paper, we extend our results in three aspects. (1) We extend detectability from deterministic systems to nondeterministic systems. Such a generalization is necessary because there are many systems that need to be modeled as nondeterministic discrete event systems. (2) We develop polynomial algorithms to check strong detectability. The previous algorithms are based on observer whose construction is of exponential complexity, while the new algorithms are based on a new automaton called detector. (3) We extend detectability to D-detectability. While detectability requires determining the exact state of a system, D-detectability relaxes this requirement by asking only to distinguish certain pairs of states. With these extensions, the theory on detectability of discrete event systems becomes more applicable in solving many practical problems. PMID:21691432

Applying Flammability Limit Probabilities and the Normoxic Upward Limiting Pressure Concept to NASA STD-6001 Test 1

NASA Technical Reports Server (NTRS)

Olson, Sandra L.; Beeson, Harold; Fernandez-Pello, A. Carlos

2014-01-01

Repeated Test 1 extinction tests near the upward flammability limit are expected to follow a Poisson process trend. This Poisson process trend suggests that rather than define a ULOI and MOC (which requires two limits to be determined), it might be better to define a single upward limit as being where 1/e (where e (approx. equal to 2.7183) is the characteristic time of the normalized Poisson process) of the materials burn, or, rounding, where approximately 1/3 of the samples fail the test (and burn). Recognizing that spacecraft atmospheres will not bound the entire oxygen-pressure parameter space, but actually lie along the normoxic atmosphere control band, we can focus the materials flammability testing along this normoxic band. A Normoxic Upward Limiting Pressure (NULP) is defined that determines the minimum safe total pressure for a material within the constant partial pressure control band. Then, increasing this pressure limit by a factor of safety, we can define the material as being safe to use at the NULP + SF (where SF is on the order of 10 kilopascal, based on existing flammability data). It is recommended that the thickest material to be tested with the current Test 1 igniter should be 3 mm thick (1/8 inches) to avoid the problem of differentiating between an ignition limit and a true flammability limit.

Genetics of human neural tube defects

PubMed Central

Greene, Nicholas D.E.; Stanier, Philip; Copp, Andrew J.

2009-01-01

Neural tube defects (NTDs) are common, severe congenital malformations whose causation involves multiple genes and environmental factors. Although more than 200 genes are known to cause NTDs in mice, there has been rather limited progress in delineating the molecular basis underlying most human NTDs. Numerous genetic studies have been carried out to investigate candidate genes in cohorts of patients, with particular reference to those that participate in folate one-carbon metabolism. Although the homocysteine remethylation gene MTHFR has emerged as a risk factor in some human populations, few other consistent findings have resulted from this approach. Similarly, attention focused on the human homologues of mouse NTD genes has contributed only limited positive findings to date, although an emerging association between genes of the non-canonical Wnt (planar cell polarity) pathway and NTDs provides candidates for future studies. Priorities for the next phase of this research include: (i) larger studies that are sufficiently powered to detect significant associations with relatively minor risk factors; (ii) analysis of multiple candidate genes in groups of well-genotyped individuals to detect possible gene–gene interactions; (iii) use of high throughput genomic technology to evaluate the role of copy number variants and to detect ‘private’ and regulatory mutations, neither of which have been studied to date; (iv) detailed analysis of patient samples stratified by phenotype to enable, for example, hypothesis-driven testing of candidates genes in groups of NTDs with specific defects of folate metabolism, or in groups of fetuses with well-defined phenotypes such as craniorachischisis. PMID:19808787

The Lactose and Galactose Content of Cheese Suitable for Galactosaemia: New Analysis.

PubMed

Portnoi, P A; MacDonald, A

2016-01-01

The UK Medical Advisory Panel of the Galactosaemia Support Group report the lactose and galactose content of 5 brands of mature Cheddar cheese, Comte and Emmi Emmental fondue mix from 32 cheese samples. The Medical Advisory Panel define suitable cheese in galactosaemia to have a lactose and galactose content consistently below 10 mg/100 g. A total of 32 samples (5 types of mature Cheddar cheese, Comte and "Emmi Swiss Fondue", an emmental fondue mix) were analysed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) technology used to perform lactose and galactose analysis. Cheddar cheese types: Valley Spire West Country, Parkham, Lye Cross Vintage, Lye Cross Mature, Tesco West Country Farmhouse Extra Mature and Sainsbury's TTD West Country Farmhouse Extra Mature had a lactose and galactose content consistently below 10 mg/100 g (range <0.05 to 12.65 mg). All Comte samples had a lactose content below the lower limit of detection (<0.05 mg) with galactose content from <0.05 to 1.86 mg/100 g; all samples of Emmi Swiss Fondue had lactose below the lower limit of detection (<0.05 mg) and galactose between 2.19 and 3.04 mg/100 g. All of these cheese types were suitable for inclusion in a low galactose diet for galactosaemia. It is possible that the galactose content of cheese may change over time depending on its processing, fermentation time and packaging techniques.

Tandem Mass Spectrometry for Structural Identification of Sesquiterpene Alkaloids from the Stems of Dendrobium nobile Using LC-QToF.

PubMed

Wang, Yan-Hong; Avula, Bharathi; Abe, Naohito; Wei, Feng; Wang, Mei; Ma, Shuang-Cheng; Ali, Zulfiqar; Elsohly, Mahmoud A; Khan, Ikhlas A

2016-05-01

Dendrobium nobile is one of the fundamental herbs in traditional Chinese medicine. Sesquiterpene alkaloids are the main active components in this plant. Due to weak ultraviolet absorption and low content in D. nobile, these sesquiterpene alkaloids have not been extensively studied using chromatographic methods. Herein, tandem mass spectrometry combined with liquid chromatography separation provides a tool for the identification and characterization of the alkaloids from D. nobile. A total of nine sesquiterpene alkaloids were characterized by ultrahigh-performance liquid chromatography tandem mass spectrometry. These alkaloids can be classified into two subgroups that are represented by dendrobine and nobilonine. Tandem mass spectrometric studies revealed the fragmentation pathways of these two subgroup alkaloids that were used for the identification and characterization of other alkaloids in D. nobile. Characterization of these alkaloids using accurate mass and diagnostic fragments provided a reliable methodology for the analysis of D. nobile by ultrahigh-performance liquid chromatography tandem mass spectrometry. The limit of detection was defined as the signal-to-noise ratio equal to 3 : 1. Limits of detection of dendrobine and nobilonine were less than 30 ng/mL. The developed method was applied for the analysis of various Dendrobium species and related dietary supplements. Alkaloids were identified from D. nobile, but not detected from commercial samples including 13 other Dendrobium species and the 7 dietary supplements. Georg Thieme Verlag KG Stuttgart · New York.

Limits to the radiative decay of the axion

NASA Technical Reports Server (NTRS)

Ressell, M. Ted

1991-01-01

An axion with a mass greater than 1 eV should be detectable through its decay into two photons. The astrophysical and cosmological limits which define a small window of allowed axion mass above 3 eV are discussed. A firm upper bound to the axion's mass of M(sub a) less than or equal to 8 eV is derived by considering the effect of decaying axions upon the diffuse extragalactic background radiation and the brightness of the night sky due to axions in the halo of the Milky Way galaxy. The intergalactic light of clusters of galaxies is shown to be an ideal place to search for an emission line arising from the radiative decay of axions. An unsuccessful search for this emission line in three clusters of galaxies is then detailed. Limits to the presence of any intracluster line emission are derived with the result that axions with masses between 3 and 8 eV are excluded by the data, effectively closing this window of axion mass, unless a severe cancellation of axionic decay amplitudes occurs. The intracluster flux limits are then used to constrain the amplitude of any such model dependence.

Repeatability of normal multifocal VEP: implications for detecting progression.

PubMed

Fortune, Brad; Demirel, Shaban; Zhang, Xian; Hood, Donald C; Johnson, Chris A

2006-04-01

To assess the repeatability of the multifocal visual evoked potential (mfVEP) and to compare it with the repeatability of standard automated perimetry (SAP) in the same group of 50 normal controls retested after 1 year. Our second aim was to assess the repeatability of false alarm rates determined previously for the mfVEP using various cluster criteria. Fifty individuals with normal vision participated in this study (33 females and 17 males). The age range was 26.7 to 77.9 years and the group average age (+/- SD) was 51.4 (+/- 12.1) years. Pattern-reversal mfVEPs were obtained using a dartboard stimulus pattern in VERIS and two 8-minute runs per eye were averaged. The average number of days between the first and second mfVEP tests was 378 (+/- 58). SAP visual fields were obtained within 17.4 (+/- 20.3) days of the mfVEP using the SITA-standard threshold algorithm. Repeatability of mfVEPs and SAP total deviation values were evaluated by calculating point-wise limits of agreement (LOA). Specificity (1-false alarm rate) was evaluated for a range of cluster criteria, whereby the number and probability level of the points defining a cluster were varied. Point-wise LOA for the mfVEP signal-to-noise ratio (SNR) ranged from 2.0 to 4.3 dB, with an average of 2.9 dB across all 60 locations. For SAP, LOA ranged from 2.4 to 8.9 dB, with an average of 4.0 dB (excluding the points immediately above and below the blind spot). Clusters of abnormal points were not likely to repeat on either mfVEP or SAP. When an mfVEP abnormality was defined as the repeat presence (confirmation) of a 3-point (P < 0.05) cluster anywhere within a single hemifield, only 1 (of 200) monocular hemifield was deemed abnormal. Although the LOA of the mfVEP were similar throughout the field, the limited dynamic range of SNR at superior field locations will limit the ability to follow progression in "depth" at those locations. Repeatability of the mfVEP was slightly better than SAP visual fields in this group of controls with a 1-year retest interval. This suggests that progression in early stages should be more easily detectable by mfVEP. However, in certain field locations (eg, superior periphery), the relatively more narrow dynamic range of the SNR of the mfVEP may limit detection of progression to just 1 event. Confirmation of a 3-point cluster abnormality is highly suggestive of a true defect on the mfVEP.

Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa

PubMed Central

Basta, David W.; Bergkessel, Megan

2017-01-01

ABSTRACT Microbial growth arrest can be triggered by diverse factors, one of which is energy limitation due to scarcity of electron donors or acceptors. Genes that govern fitness during energy-limited growth arrest and the extent to which they overlap between different types of energy limitation are poorly defined. In this study, we exploited the fact that Pseudomonas aeruginosa can remain viable over several weeks when limited for organic carbon (pyruvate) as an electron donor or oxygen as an electron acceptor. ATP values were reduced under both types of limitation, yet more severely in the absence of oxygen. Using transposon-insertion sequencing (Tn-seq), we identified fitness determinants in these two energy-limited states. Multiple genes encoding general functions like transcriptional regulation and energy generation were required for fitness during carbon or oxygen limitation, yet many specific genes, and thus specific activities, differed in their relevance between these states. For instance, the global regulator RpoS was required during both types of energy limitation, while other global regulators such as DksA and LasR were required only during carbon or oxygen limitation, respectively. Similarly, certain ribosomal and tRNA modifications were specifically required during oxygen limitation. We validated fitness defects during energy limitation using independently generated mutants of genes detected in our screen. Mutants in distinct functional categories exhibited different fitness dynamics: regulatory genes generally manifested a phenotype early, whereas genes involved in cell wall metabolism were required later. Together, these results provide a new window into how P. aeruginosa survives growth arrest. PMID:29184024

Exploring machine-learning-based control plane intrusion detection techniques in software defined optical networks

NASA Astrophysics Data System (ADS)

Zhang, Huibin; Wang, Yuqiao; Chen, Haoran; Zhao, Yongli; Zhang, Jie

2017-12-01

In software defined optical networks (SDON), the centralized control plane may encounter numerous intrusion threatens which compromise the security level of provisioned services. In this paper, the issue of control plane security is studied and two machine-learning-based control plane intrusion detection techniques are proposed for SDON with properly selected features such as bandwidth, route length, etc. We validate the feasibility and efficiency of the proposed techniques by simulations. Results show an accuracy of 83% for intrusion detection can be achieved with the proposed machine-learning-based control plane intrusion detection techniques.

Automatic quadrature control and measuring system. [using optical coupling circuitry

NASA Technical Reports Server (NTRS)

Hamlet, J. F. (Inventor)

1974-01-01

A quadrature component cancellation and measuring system comprising a detection system for detecting the quadrature component from a primary signal, including reference circuitry to define the phase of the quadrature component for detection is described. A Raysistor optical coupling control device connects an output from the detection system to a circuit driven by a signal based upon the primary signal. Combining circuitry connects the primary signal and the circuit controlled by the Raysistor device to subtract quadrature components. A known current through the optically sensitive element produces a signal defining the magnitude of the quadrature component.

No apparent influence of psychometrically-defined schizotypy on orientation-dependent contextual modulation of visual contrast detection.

PubMed

Mannion, Damien J; Donkin, Chris; Whitford, Thomas J

2017-01-01

We investigated the relationship between psychometrically-defined schizotypy and the ability to detect a visual target pattern. Target detection is typically impaired by a surrounding pattern (context) with an orientation that is parallel to the target, relative to a surrounding pattern with an orientation that is orthogonal to the target (orientation-dependent contextual modulation). Based on reports that this effect is reduced in those with schizophrenia, we hypothesised that there would be a negative relationship between the relative score on psychometrically-defined schizotypy and the relative effect of orientation-dependent contextual modulation. We measured visual contrast detection thresholds and scores on the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) from a non-clinical sample ( N = 100). Contrary to our hypothesis, we find an absence of a monotonic relationship between the relative magnitude of orientation-dependent contextual modulation of visual contrast detection and the relative score on any of the subscales of the O-LIFE. The apparent difference of this result with previous reports on those with schizophrenia suggests that orientation-dependent contextual modulation may be an informative condition in which schizophrenia and psychometrically-defined schizotypy are dissociated. However, further research is also required to clarify the strength of orientation-dependent contextual modulation in those with schizophrenia.

Quantitative analysis of amoxicillin, its major metabolites and ampicillin in eggs by liquid chromatography combined with electrospray ionization tandem mass spectrometry.

PubMed

Sun, Lirui; Jia, Longfei; Xie, Xing; Xie, Kaizhou; Wang, Jianfeng; Liu, Jianyu; Cui, Lulu; Zhang, Genxi; Dai, Guojun; Wang, Jinyu

2016-02-01

In this present study, we developed a simple, rapid and specific method for the quantitative analysis of the contents of amoxicillin (AMO), AMO metabolites and ampicillin (AMP) in eggs. This method uses a simple liquid-liquid extraction with acetonitrile followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimized method has been validated according to requirements defined by the European Union and Food and Drug Administration. Extraction recoveries of the target compounds from the egg at 5, 10 and 25 μg/kg were all higher than 80%, with relative standard deviations not exceeding 10.00%. The limits of quantification in eggs were below the maximum residue limits (MRLs). The decision limits (CCα) ranged between 11.1 and 11.5 μg/kg, while detection capabilities (CCβ) from 12.1 to 13.0 μg/kg. These values were very close to the corresponding MRLs. Finally, the new approach was successfully verified for the quantitative determination of these analytes in 40 commercial eggs from local supermarkets. Copyright © 2015 Elsevier Ltd. All rights reserved.

Short-wavelength automated perimetry and frequency-doubling technology perimetry in glaucoma.

PubMed

Fogagnolo, Paolo; Rossetti, Luca; Ranno, Stefano; Ferreras, Antonio; Orzalesi, Nicola

2008-01-01

Standard automated perimetry (SAP) is today still the clinical standard for the management of glaucoma and its progression, though it has been shown that it may detect the disease only after the death of a high number of retinal ganglion cells (RGCs). A number of "unconventional" perimetries have recently been evaluated by several clinical studies which showed their ability to identify the earliest glaucoma changes; the most promising of these techniques are short-wavelength automated perimetry (SWAP) and frequency-doubling technology perimetry (FDT). The applicability of these techniques is still limited by a number of factors: the limited economic resources allocated to perimetry; the paucity of well-conducted, prospective longitudinal studies showing the superiority of SWAP and FDT over SAP; and the lack of a consensus on the criteria to define test abnormality with these techniques. The aim of this article is to review the rationale, the limits, and the potentiality of SWAP and FDT for glaucoma management and to summarize the tasks required to improve the clinical usefulness of these two instruments in the future.

Serum cystatin C- versus creatinine-based definitions of acute kidney injury following cardiac surgery: a prospective cohort study.

PubMed

Spahillari, Aferdita; Parikh, Chirag R; Sint, Kyaw; Koyner, Jay L; Patel, Uptal D; Edelstein, Charles L; Passik, Cary S; Thiessen-Philbrook, Heather; Swaminathan, Madhav; Shlipak, Michael G

2012-12-01

The primary aim of this study was to compare the sensitivity and rapidity of acute kidney injury (AKI) detection by cystatin C level relative to creatinine level after cardiac surgery. Prospective cohort study. 1,150 high-risk adult cardiac surgery patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium. Changes in serum creatinine and cystatin C levels. Postsurgical incidence of AKI. Serum creatinine and cystatin C were measured at the preoperative visit and daily on postoperative days 1-5. To allow comparisons between changes in creatinine and cystatin C levels, AKI end points were defined by the relative increases in each marker from baseline (25%, 50%, and 100%) and the incidence of AKI was compared based on each marker. Secondary aims were to compare clinical outcomes among patients defined as having AKI by cystatin C and/or creatinine levels. Overall, serum creatinine level detected more cases of AKI than cystatin C level: 35% developed a ≥25% increase in serum creatinine level, whereas only 23% had a ≥25% increase in cystatin C level (P < 0.001). Creatinine level also had higher proportions meeting the 50% (14% and 8%; P < 0.001) and 100% (4% and 2%; P = 0.005) thresholds for AKI diagnosis. Clinical outcomes generally were not statistically different for AKI cases detected by creatinine or cystatin C level. However, for each AKI threshold, patients with AKI confirmed by both markers had a significantly higher risk of the combined mortality/dialysis outcome compared with patients with AKI detected by creatinine level alone (P = 0.002). There were few adverse clinical outcomes, limiting our ability to detect differences in outcomes between subgroups of patients based on their definitions of AKI. In this large multicenter study, we found that cystatin C level was less sensitive for AKI detection than creatinine level. However, confirmation by cystatin C level appeared to identify a subset of patients with AKI with a substantially higher risk of adverse outcomes. Published by Elsevier Inc.

Using light-dependent scleractinia to define the upper boundary of mesophotic coral ecosystems on the reefs of Utila, Honduras.

PubMed

Laverick, Jack H; Andradi-Brown, Dominic A; Rogers, Alex D

2017-01-01

Shallow water zooxanthellate coral reefs grade into ecologically distinct mesophotic coral ecosystems (MCEs) deeper in the euphotic zone. MCEs are widely considered to start at an absolute depth limit of 30m deep, possibly failing to recognise that these are distinct ecological communities that may shift shallower or deeper depending on local environmental conditions. This study aimed to explore whether MCEs represent distinct biological communities, the upper boundary of which can be defined and whether the depth at which they occur may vary above or below 30m. Mixed-gas diving and closed-circuit rebreathers were used to quantitatively survey benthic communities across shallow to mesophotic reef gradients around the island of Utila, Honduras. Depths of up to 85m were sampled, covering the vertical range of the zooxanthellate corals around Utila. We investigate vertical reef zonation using a variety of ecological metrics to identify community shifts with depth, and the appropriateness of different metrics to define the upper MCE boundary. Patterns observed in scleractinian community composition varied between ordination analyses and approaches utilising biodiversity indices. Indices and richness approaches revealed vertical community transition was a gradation. Ordination approaches suggest the possibility of recognising two scleractinian assemblages. We could detect a mesophotic and shallow community while illustrating that belief in a static depth limit is biologically unjustified. The switch between these two communities occurred across bathymetric gradients as small as 10m and as large as 50m in depth. The difference between communities appears to be a loss of shallow specialists and increase in depth-generalist taxa. Therefore, it may be possible to define MCEs by a loss of shallow specialist species. To support a biological definition of mesophotic reefs, we advocate this analytical framework should be applied around the Caribbean and extended into other ocean basins where MCEs are present.

Evolution of a Reconfigurable Processing Platform for a Next Generation Space Software Defined Radio

NASA Technical Reports Server (NTRS)

Kacpura, Thomas J.; Downey, Joseph A.; Anderson, Keffery R.; Baldwin, Keith

2014-01-01

The National Aeronautics and Space Administration (NASA)Harris Ka-Band Software Defined Radio (SDR) is the first, fully reprogrammable space-qualified SDR operating in the Ka-Band frequency range. Providing exceptionally higher data communication rates than previously possible, this SDR offers in-orbit reconfiguration, multi-waveform operation, and fast deployment due to its highly modular hardware and software architecture. Currently in operation on the International Space Station (ISS), this new paradigm of reconfigurable technology is enabling experimenters to investigate navigation and networking in the space environment.The modular SDR and the NASA developed Space Telecommunications Radio System (STRS) architecture standard are the basis for Harris reusable, digital signal processing space platform trademarked as AppSTAR. As a result, two new space radio products are a synthetic aperture radar payload and an Automatic Detection Surveillance Broadcast (ADS-B) receiver. In addition, Harris is currently developing many new products similar to the Ka-Band software defined radio for other applications. For NASAs next generation flight Ka-Band radio development, leveraging these advancements could lead to a more robust and more capable software defined radio.The space environment has special considerations different from terrestrial applications that must be considered for any system operated in space. Each space mission has unique requirements that can make these systems unique. These unique requirements can make products that are expensive and limited in reuse. Space systems put a premium on size, weight and power. A key trade is the amount of reconfigurability in a space system. The more reconfigurable the hardware platform, the easier it is to adapt to the platform to the next mission, and this reduces the amount of non-recurring engineering costs. However, the more reconfigurable platforms often use more spacecraft resources. Software has similar considerations to hardware. Having an architecture standard promotes reuse of software and firmware. Space platforms have limited processor capability, which makes the trade on the amount of amount of flexibility paramount.

Influence of lung CT changes in chronic obstructive pulmonary disease (COPD) on the human lung microbiome

PubMed Central

Schloter-Hai, Brigitte; Kublik, Susanne; Granitsiotis, Michael S.; Boschetto, Piera; Stendardo, Mariarita; Barta, Imre; Dome, Balazs; Deleuze, Jean-François; Boland, Anne; Müller-Quernheim, Joachim; Prasse, Antje; Welte, Tobias; Hohlfeld, Jens; Subramanian, Deepak; Parr, David; Gut, Ivo Glynne; Greulich, Timm; Koczulla, Andreas Rembert; Nowinski, Adam; Gorecka, Dorota; Singh, Dave; Gupta, Sumit; Brightling, Christopher E.; Hoffmann, Harald; Frankenberger, Marion; Hofer, Thomas P.; Burggraf, Dorothe; Heiss-Neumann, Marion; Ziegler-Heitbrock, Loems; Schloter, Michael; zu Castell, Wolfgang

2017-01-01

Background Changes in microbial community composition in the lung of patients suffering from moderate to severe COPD have been well documented. However, knowledge about specific microbiome structures in the human lung associated with CT defined abnormalities is limited. Methods Bacterial community composition derived from brush samples from lungs of 16 patients suffering from different CT defined subtypes of COPD and 9 healthy subjects was analyzed using a cultivation independent barcoding approach applying 454-pyrosequencing of 16S rRNA gene fragment amplicons. Results We could show that bacterial community composition in patients with changes in CT (either airway or emphysema type changes, designated as severe subtypes) was different from community composition in lungs of patients without visible changes in CT as well as from healthy subjects (designated as mild COPD subtype and control group) (PC1, Padj = 0.002). Higher abundance of Prevotella in samples from patients with mild COPD subtype and from controls and of Streptococcus in the severe subtype cases mainly contributed to the separation of bacterial communities of subjects. No significant effects of treatment with inhaled glucocorticoids on bacterial community composition were detected within COPD cases with and without abnormalities in CT in PCoA. Co-occurrence analysis suggests the presence of networks of co-occurring bacteria. Four communities of positively correlated bacteria were revealed. The microbial communities can clearly be distinguished by their associations with the CT defined disease phenotype. Conclusion Our findings indicate that CT detectable structural changes in the lung of COPD patients, which we termed severe subtypes, are associated with alterations in bacterial communities, which may induce further changes in the interaction between microbes and host cells. This might result in a changed interplay with the host immune system. PMID:28704452

Influence of lung CT changes in chronic obstructive pulmonary disease (COPD) on the human lung microbiome.

PubMed

Engel, Marion; Endesfelder, David; Schloter-Hai, Brigitte; Kublik, Susanne; Granitsiotis, Michael S; Boschetto, Piera; Stendardo, Mariarita; Barta, Imre; Dome, Balazs; Deleuze, Jean-François; Boland, Anne; Müller-Quernheim, Joachim; Prasse, Antje; Welte, Tobias; Hohlfeld, Jens; Subramanian, Deepak; Parr, David; Gut, Ivo Glynne; Greulich, Timm; Koczulla, Andreas Rembert; Nowinski, Adam; Gorecka, Dorota; Singh, Dave; Gupta, Sumit; Brightling, Christopher E; Hoffmann, Harald; Frankenberger, Marion; Hofer, Thomas P; Burggraf, Dorothe; Heiss-Neumann, Marion; Ziegler-Heitbrock, Loems; Schloter, Michael; Zu Castell, Wolfgang

2017-01-01

Changes in microbial community composition in the lung of patients suffering from moderate to severe COPD have been well documented. However, knowledge about specific microbiome structures in the human lung associated with CT defined abnormalities is limited. Bacterial community composition derived from brush samples from lungs of 16 patients suffering from different CT defined subtypes of COPD and 9 healthy subjects was analyzed using a cultivation independent barcoding approach applying 454-pyrosequencing of 16S rRNA gene fragment amplicons. We could show that bacterial community composition in patients with changes in CT (either airway or emphysema type changes, designated as severe subtypes) was different from community composition in lungs of patients without visible changes in CT as well as from healthy subjects (designated as mild COPD subtype and control group) (PC1, Padj = 0.002). Higher abundance of Prevotella in samples from patients with mild COPD subtype and from controls and of Streptococcus in the severe subtype cases mainly contributed to the separation of bacterial communities of subjects. No significant effects of treatment with inhaled glucocorticoids on bacterial community composition were detected within COPD cases with and without abnormalities in CT in PCoA. Co-occurrence analysis suggests the presence of networks of co-occurring bacteria. Four communities of positively correlated bacteria were revealed. The microbial communities can clearly be distinguished by their associations with the CT defined disease phenotype. Our findings indicate that CT detectable structural changes in the lung of COPD patients, which we termed severe subtypes, are associated with alterations in bacterial communities, which may induce further changes in the interaction between microbes and host cells. This might result in a changed interplay with the host immune system.

A Methodology for Determining Statistical Performance Compliance for Airborne Doppler Radar with Forward-Looking Turbulence Detection Capability

NASA Technical Reports Server (NTRS)

Bowles, Roland L.; Buck, Bill K.

2009-01-01

The objective of the research developed and presented in this document was to statistically assess turbulence hazard detection performance employing airborne pulse Doppler radar systems. The FAA certification methodology for forward looking airborne turbulence radars will require estimating the probabilities of missed and false hazard indications under operational conditions. Analytical approaches must be used due to the near impossibility of obtaining sufficient statistics experimentally. This report describes an end-to-end analytical technique for estimating these probabilities for Enhanced Turbulence (E-Turb) Radar systems under noise-limited conditions, for a variety of aircraft types, as defined in FAA TSO-C134. This technique provides for one means, but not the only means, by which an applicant can demonstrate compliance to the FAA directed ATDS Working Group performance requirements. Turbulence hazard algorithms were developed that derived predictive estimates of aircraft hazards from basic radar observables. These algorithms were designed to prevent false turbulence indications while accurately predicting areas of elevated turbulence risks to aircraft, passengers, and crew; and were successfully flight tested on a NASA B757-200 and a Delta Air Lines B737-800. Application of this defined methodology for calculating the probability of missed and false hazard indications taking into account the effect of the various algorithms used, is demonstrated for representative transport aircraft and radar performance characteristics.

Old tree with new shoots: silver nanoparticles for label-free and colorimetric mercury ions detection

NASA Astrophysics Data System (ADS)

Gao, Shuyan; Jia, Xiaoxia; Chen, Yanli

2013-01-01

Mercury in the environment from global mercury emissions as well as various forms of contamination poses severe threats to both human health and the environment. Long-term exposure to high levels of Hg-based toxins results in serious and irreversible damage of the central nervous system and other organs. Therefore, the development of effective sensing systems for mercury detection becomes an increasing demand. In this article, a yogurt-mediated silver nanostructure is reported to be unprecedentedly used in the naked-eye and label-free detection of mercury. The method relies on the redox reaction resulting from the electrode potential difference between Ag+/Ag (0.7996 V) and Hg2+/Hg2 2+ (0.920 V) that makes colorless Hg2+ ions which oxidize colored silver nanoparticle (AgNP) to colorless Ag+. The labor-intensive modification of AgNPs and expensive labeling are avoided, and the traditional AuNPs are substituted by AgNPs in this Hg2+ ions sensing platform, which makes it facile, low-cost, and particularly useful for home, clinic, or field applications as well as resource-limited conditions. This sensing system achieves a detection limit as low as 10 nM, lower than the toxicity level of Hg2+ ions in drinking water (30 nM) defined by World Health Organization, and exhibits excellent selectivity, largely free from the matrix effect of the real water samples. This visual label-free Hg2+ ions sensing motif shows great promise for sensing Hg2+ ions in terms of sensitivity, selectivity, cost, and maneuverability. It is also a good example for the organic combination of green chemistry and functional materials, which may trigger interest in furthering biosystems for environmental science applications.

Observing secretory granules with a multiangle evanescent wave microscope.

PubMed Central

Rohrbach, A

2000-01-01

In total internal reflection fluorescence microscopy (TIRFM), fluorophores near a surface can be excited with evanescent waves, which decay exponentially with distance from the interface. Penetration depths of evanescent waves from 60 nm to 300 nm were generated by varying the angle of incidence of a laser beam. With a novel telecentric multiangle evanescent wave microscope, we monitored and investigated both single secretory granules and pools of granules in bovine chromaffin cells. By measuring the fluorescence intensity as a function of penetration depth, it is possible through a Laplace transform to obtain the fluorophore distribution as a function of axial position. We discuss the extent to which it is possible to determine distances and diameters of granules with this microscopy technique by modeling the fluorescent volumes of spheres in evanescent fields. The anisotropic near-field detection of fluorophores and the influence of the detection point-spread function are considered. The diameters of isolated granules between 70 nm and 300 nm have been reconstructed, which is clearly beyond the resolution limit of a confocal microscope. Furthermore, the paper demonstrates how evanescent waves propagate along surfaces and scatter at objects with a higher refractive index. TIRFM will have a limited applicability for quantitative measurements when the parameters used to define evanescent waves are not optimally selected. PMID:10777760

Imaging terahertz radar for security applications

NASA Astrophysics Data System (ADS)

Semenov, Alexei; Richter, Heiko; Böttger, Ute; Hübers, Heinz-Wilhelm

2008-04-01

Detection of concealed threats is a key issue in public security. In short range applications, passive imagers operating at millimeter wavelengths fulfill this task. However, for larger distances, they will suffer from limited spatial resolution. We will describe the design and performance of 0.8-THz imaging radar that is capable to detect concealed objects at a distance of more than 20 meter. The radar highlights the target with the built-in cw transmitter and analyses the returned signal making use of a heterodyne receiver with a single superconducting hot-electron bolometric mixer. With an integration time of 0.3 sec, the receiver distinguishes a temperature difference of 2 K at the 20 m distance. Both the transmitter and the receiver use the same modified Gregorian telescope consisting from two offset elliptic mirrors. The primary mirror defines limits the lateral resolution of the radar to 2 cm at 20 m distance. At this distance, the field of view of the radar has the diameter 0.5 m. It is sampled with a high-speed conical scanner that allows for a frame time less than 5 sec. The transmitter delivers to the target power with a density less than ten microwatt per squared centimeter, which is harmless for human beings. The radar implements a sensor fusion technique that greatly improves the ability to identify concealed objects.

Direct electrochemistry of glucose oxidase and glucose biosensing on a hydroxyl fullerenes modified glassy carbon electrode.

PubMed

Gao, Yun-Fei; Yang, Tian; Yang, Xiao-Lu; Zhang, Yu-Shuai; Xiao, Bao-Lin; Hong, Jun; Sheibani, Nader; Ghourchian, Hedayatollah; Hong, Tao; Moosavi-Movahedi, Ali Akbar

2014-10-15

Direct electrochemistry of glucose oxidase (GOD) was achieved when GOD-hydroxyl fullerenes (HFs) nano-complex was immobilized on a glassy carbon (GC) electrode and protected with a chitosan (Chit) membrane. The ultraviolet-visible absorption spectrometry (UV-vis), transmission electron microscopy (TEM), and circular dichroism spectropolarimeter (CD) methods were utilized for additional characterization of the GOD, GOD-HFs and Chit/GOD-HFs. Chit/HFs may preserve the secondary structure and catalytic properties of GOD. The cyclic voltammograms (CVs) of the modified GC electrode showed a pair of well-defined quasi-reversible redox peaks with the formal potential (E°') of 353 ± 2 mV versus Ag/AgCl at a scan rate of 0.05 V/s. The heterogeneous electron transfer constant (ks) was calculated to be 2.7 ± 0.2s(-1). The modified electrode response to glucose was linear in the concentrations ranging from 0.05 to 1.0mM, with a detection limit of 5 ± 1 μM. The apparent Michaelis-Menten constant (Km(app)) was 694 ± 8 μM. Thus, the modified electrode could be applied as a third generation biosensor for glucose with high sensitivity, selectivity and low detection limit. Copyright © 2014 Elsevier B.V. All rights reserved.

Measuring and statistically testing the size of the effect of a chemical compound on a continuous in-vitro pharmacological response through a new statistical model of response detection limit

PubMed Central

Diaz, Francisco J.; McDonald, Peter R.; Pinter, Abraham; Chaguturu, Rathnam

2018-01-01

Biomolecular screening research frequently searches for the chemical compounds that are most likely to make a biochemical or cell-based assay system produce a strong continuous response. Several doses are tested with each compound and it is assumed that, if there is a dose-response relationship, the relationship follows a monotonic curve, usually a version of the median-effect equation. However, the null hypothesis of no relationship cannot be statistically tested using this equation. We used a linearized version of this equation to define a measure of pharmacological effect size, and use this measure to rank the investigated compounds in order of their overall capability to produce strong responses. The null hypothesis that none of the examined doses of a particular compound produced a strong response can be tested with this approach. The proposed approach is based on a new statistical model of the important concept of response detection limit, a concept that is usually neglected in the analysis of dose-response data with continuous responses. The methodology is illustrated with data from a study searching for compounds that neutralize the infection by a human immunodeficiency virus of brain glioblastoma cells. PMID:24905187

Optimal strategies for observation of active galactic nuclei variability with Imaging Atmospheric Cherenkov Telescopes

NASA Astrophysics Data System (ADS)

Giomi, Matteo; Gerard, Lucie; Maier, Gernot

2016-07-01

Variable emission is one of the defining characteristic of active galactic nuclei (AGN). While providing precious information on the nature and physics of the sources, variability is often challenging to observe with time- and field-of-view-limited astronomical observatories such as Imaging Atmospheric Cherenkov Telescopes (IACTs). In this work, we address two questions relevant for the observation of sources characterized by AGN-like variability: what is the most time-efficient way to detect such sources, and what is the observational bias that can be introduced by the choice of the observing strategy when conducting blind surveys of the sky. Different observing strategies are evaluated using simulated light curves and realistic instrument response functions of the Cherenkov Telescope Array (CTA), a future gamma-ray observatory. We show that strategies that makes use of very small observing windows, spread over large periods of time, allows for a faster detection of the source, and are less influenced by the variability properties of the sources, as compared to strategies that concentrate the observing time in a small number of large observing windows. Although derived using CTA as an example, our conclusions are conceptually valid for any IACTs facility, and in general, to all observatories with small field of view and limited duty cycle.

Molecularly imprinted polymers for the detection of illegal drugs and additives: a review.

PubMed

Xiao, Deli; Jiang, Yue; Bi, Yanping

2018-04-04

This review (with 154 refs.) describes the current status of using molecularly imprinted polymers in the extraction and quantitation of illicit drugs and additives. The review starts with an introduction into some synthesis methods (lump MIPs, spherical MIPs, surface imprinting) of MIPs using illicit drugs and additives as templates. The next section covers applications, with subsections on the detection of illegal additives in food, of doping in sports, and of illicit addictive drugs. A particular focus is directed towards current limitations and challenges, on the optimization of methods for preparation of MIPs, their applicability to aqueous samples, the leakage of template molecules, and the identification of the best balance between adsorption capacity and selectivity factor. At last, the need for convincing characterization methods, the lack of uniform parameters for defining selectivity, and the merits and demerits of MIPs prepared using nanomaterials are addressed. Strategies are suggested to solve existing problems, and future developments are discussed with respect to a more widespread use in relevant fields. Graphical abstract This review gives a comprehensive overview of the advances made in molecularly imprinting of polymers for use in the extraction and quantitation of illicit drugs and additives. Methods for syntheses, highlighted applications, limitations and current challenges are specifically addressed.

Hydrogen peroxide biosensor based on a myoglobin/hydrophilic room temperature ionic liquid film.

PubMed

Safavi, Afsaneh; Farjami, Fatemeh

2010-07-01

The composite film based on Nafion and hydrophilic room temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium chloride ([bmim]Cl) was used as an immobilization matrix to entrap myoglobin (Mb). The study of ionic liquid (IL)-Mb interaction by ultraviolet-visible (UV-vis) spectroscopy showed that Mb retains its native conformation in the presence of IL. The immobilized Mb displayed a pair of well-defined cyclic voltammetric peaks with a formal potential (E(o)(')) of -0.35 V in a 0.1 M phosphate buffer solution (PBS) of pH 7.0. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide, based on which a mediator-free amperometric biosensor for hydrogen peroxide was designed. The linear range for the determination of hydrogen peroxide was from 1.0 to 180 microM with a detection limit of 0.14 microM at a signal/noise ratio of 3. The apparent Michaelis constant (K(m)(app)) for the electrocatalytic reaction was 22.6 microM. The stability, repeatability, and selectivity of the sensor were evaluated. The proposed biosensor has a lower detection limit than many other IL-heme protein-based biosensors and is free from common interference in hydrogen peroxide biosensors. 2010 Elsevier Inc. All rights reserved.

Multi-species sensing using multi-mode absorption spectroscopy with mid-infrared interband cascade lasers

NASA Astrophysics Data System (ADS)

O'Hagan, S.; Northern, J. H.; Gras, B.; Ewart, P.; Kim, C. S.; Kim, M.; Merritt, C. D.; Bewley, W. W.; Canedy, C. L.; Vurgaftman, I.; Meyer, J. R.

2016-06-01

The application of an interband cascade laser, ICL, to multi-mode absorption spectroscopy, MUMAS, in the mid-infrared region is reported. Measurements of individual mode linewidths of the ICL, derived from the pressure dependence of lineshapes in MUMAS signatures of single, isolated, lines in the spectrum of HCl, were found to be in the range 10-80 MHz. Multi-line spectra of methane were recorded using spectrally limited bandwidths, of approximate width 27 cm-1, defined by an interference filter, and consist of approximately 80 modes at spectral locations spanning the 100 cm-1 bandwidth of the ICL output. Calibration of the methane pressures derived from MUMAS data using a capacitance manometer provided measurements with an uncertainty of 1.1 %. Multi-species sensing is demonstrated by the simultaneous detection of methane, acetylene and formaldehyde in a gas mixture. Individual partial pressures of the three gases are derived from best fits of model MUMAS signatures to the data with an experimental error of 10 %. Using an ICL, with an inter-mode interval of ~10 GHz, MUMAS spectra were recorded at pressures in the range 1-10 mbar, and, based on the data, a potential minimum detection limit of the order of 100 ppmv is estimated for MUMAS at atmospheric pressure using an inter-mode interval of 80 GHz.

Detoxification of mercury, cadmium, and lead in Klebsiella aerogenes NCTC 418 growing in continuous culture

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

Aiking, H.; Govers, H.; van 'T Riet, J.

1985-11-01

Klebsiella aerogenes NCTC 418 growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture exhibited sulfide formation and P/sub i/ accumulation as the only demonstrable detoxification mechanisms. In the presence of mercury under similar conditions only HgS formation could be confirmed, by an increased sensitivity to mercury under sulfate-limited conditions, among others. The fact that the cells were most sensitive to cadmium under conditions of phosphate limitation and most sensitive to mercury under conditions of sulfate limitation led to the hypothesis that these inorganic detoxification mechanisms generally depended on a kind of facilitated precipitation. Themore » process was coined thus because heavy metals were probably accumulated and precipitated near the cell perimeter due to the relatively high local concentrations of sulfide and phosphate there. Depending on the growth-limiting nutrient, mercury proved to be 25-fold (phosphate limitation), 75-fold (glycerol limitation), or 150-fold (sulfate limitation) more toxic than cadmium to this organism. In the presence of lead, PbS formation was suggested. since no other detoxification mechanisms were detected, for example, rendering heavy metal ions innocuous as metallo-organic compounds, it was concluded that formation of heavy metal precipitates is crucially important to this organism. In addition, it was observed that several components of a defined mineral medium were able to reduce mercuric ions to elemental mercury. This abiotic mercury volatilization was studied in detail, and its general and environmental implications are discussed.« less

Alpha Cluster Structure in 16O

NASA Astrophysics Data System (ADS)

Dias Rodrigues, Márcia Regina; Borello-Lewin, Thereza; Miyake, Hideaki; Cappuzzello, Francesco; Cavallaro, Manuela; Duarte, José Luciano Miranda; Lima Rodrigues, Cleber; de Souza, Marco Antonio; Horodynski-Matsushigue, Brighitta; Cunsolo, Angelo; Foti, Antonio; Mitsuo Ukita, Gilberto; Neto de Faria, Pedro; Agodi, Clementina; De Napoli, Marzio; Nicolosi, Dario; Bondì, Dario; Carbone, Diana; Tropea, Stefania

2014-03-01

The main purpose of the present work is the investigation of the α-cluster phenomenon in 16O. The 12C(6Li,d)16O reaction was measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. Resonant states around 4α threshold were measured and an energy resolution of 15 keV allows to define states previously unresolved. The angular distributions of the absolute cross sections were determined in a range of 4-40 degree in the center of mass system. The upper limit for the resonance widths was obtained, indicating that the a cluster structure information in this region should be revised.

Sensitive Precise p H Measurement with Large-Area Graphene Field-Effect Transistors at the Quantum-Capacitance Limit

NASA Astrophysics Data System (ADS)

Fakih, Ibrahim; Mahvash, Farzaneh; Siaj, Mohamed; Szkopek, Thomas

2017-10-01

A challenge for p H sensing is decreasing the minimum measurable p H per unit bandwidth in an economical fashion. Minimizing noise to reach the inherent limit imposed by charge fluctuation remains an obstacle. We demonstrate here graphene-based ion-sensing field-effect transistors that saturate the physical limit of sensitivity, defined here as the change in electrical response with respect to p H , and achieve a precision limited by charge-fluctuation noise at the sensing layer. We present a model outlining the necessity for maximizing the device carrier mobility, active sensing area, and capacitive coupling in order to minimize noise. We encapsulate large-area graphene with an ultrathin layer of parylene, a hydrophobic polymer, and deposit an ultrathin, stoichiometric p H -sensing layer of either aluminum oxide or tantalum pentoxide. With these structures, we achieve gate capacitances ˜0.6 μ F /cm2 , approaching the quantum-capacitance limit inherent to graphene, along with a near-Nernstian p H response of ˜55 ±2 mV /p H . We observe field-effect mobilities as high as 7000 cm2 V-1 s-1 with minimal hysteresis as a result of the parylene encapsulation. A detection limit of 0.1 m p H in a 60-Hz electrical bandwidth is observed in optimized graphene transistors.

Defined by Limitations

ERIC Educational Resources Information Center

Arriola, Sonya; Murphy, Katy

2010-01-01

Undocumented students are a population defined by limitations. Their lack of legal residency and any supporting paperwork (e.g., Social Security number, government issued identification) renders them essentially invisible to the American and state governments. They cannot legally work. In many states, they cannot legally drive. After the age of…

Defining overweight and obesity among Greek children living in Thessaloniki: International versus local reference standards

PubMed Central

Christoforidis, A; Dimitriadou, M; Papadopolou, E; Stilpnopoulou, D; Katzos, G; Athanassiou-Metaxa, M

2011-01-01

Background: Body Mass Index (BMI) offers a simple and reasonable measure of obesity that, with the use of the appropriate reference, can help in the early detection of children with weight problems. Our aim was to compare the two most commonly used international BMI references and the national Greek BMI reference in identifying Greek children being overweight and obese. Methods: A group of 1557 children (820 girls and 737 boys, mean age: 11.42 ± 3.51 years) were studied. Weight and height was measured using standard methods, and BMI was calculated. Overweight and obesity were determined using the International Obesity Task Force (IOTF) standards, the Centers for Disease Control and Prevention (CDC) BMI-forage curves and the most recent Greek BMI-for-age curves. Results: Results showed that the IOTF's cut-off limits identifies a significantly higher prevalence of overweight (22.4%) compared with both the CDC's (11.8%, p=0.03) and the Greek's (7.4%, p=0.002) cut-off limits. However, the prevalence of obesity was generally increased when it was determined using the CDC's cut-off limits (13.9%) compared to the prevalence calculated with both the IOTF's (6.5%, p=0.05) and the Greek's (6.9%, n.s.) cut off limits. Conclusions: The use of the national Greek reference standards for BMI underestimates the true prevalence of overweight and obesity. On the contrary, both the IOTF and the CDC standards, although independently, detect an increased number of overweight and obese children and thus they should be adopted in the clinical practice for an earlier identification and a timelier intervention. PMID:22110296

A highly selective and fast-response fluorescent probe based on Cd-MOF for the visual detection of Al3+ ion and quantitative detection of Fe3+ ion

NASA Astrophysics Data System (ADS)

Lv, Rui; Chen, Zhihengyu; Fu, Xin; Yang, Boyi; Li, Hui; Su, Jian; Gu, Wen; Liu, Xin

2018-03-01

A new luminescent Cd(II)-based metal-organic framework, [Cd(PAM)(4-bpdb)1.5]·DMF (Cd-MOF, PAM = 4,4‧-methylenebis(3-hydroxy-2-naphthalene-carboxylic acid) and 4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) was successfully synthesized by solvothermal synthesis method. The Cd-MOF reveals excellent luminescence property which can selectively detect Al3+ and Fe3+ ions among other interfering metal ions. The detection limit is 0.56 μM for Al3+ ion in aqueous solutions, and it is obvious lower than the maximum standard of Al3+ ion in drinking water of 7.41 μM which is defined by the WHO. More importantly, the Cd-MOF shows an obvious luminescent color change from yellow to blue under the UV lamp irradiation at 365 nm with the dropping of Al3+ ion, which can make it apply to the visual detection. And, the detection based on the test paper was explored for the first time. In addition, the Cd-MOF can also be used for quantitative detecting Fe3+ ion, and the LOD for Fe3+ ion can be as low as 0.3 μM which is lower than most reported MOFs. It is worth noting that Fe3+ and Al3+ ions can not interfere with each other. These properties make it become an excellent luminescence sensor for the detection of Al3+ and Fe3+ ions.

An Ultra-Trace Analysis Technique for SF6 Using Gas Chromatography with Negative Ion Chemical Ionization Mass Spectrometry.

PubMed

Jong, Edmund C; Macek, Paul V; Perera, Inoka E; Luxbacher, Kray D; McNair, Harold M

2015-07-01

Sulfur hexafluoride (SF6) is widely used as a tracer gas because of its detectability at low concentrations. This attribute of SF6 allows the quantification of both small-scale flows, such as leakage, and large-scale flows, such as atmospheric currents. SF6's high detection sensitivity also facilitates greater usage efficiency and lower operating cost for tracer deployments by reducing quantity requirements. The detectability of SF6 is produced by its high molecular electronegativity. This property provides a high potential for negative ion formation through electron capture thus naturally translating to selective detection using negative ion chemical ionization mass spectrometry (NCI-MS). This paper investigates the potential of using gas chromatography (GC) with NCI-MS for the detection of SF6. The experimental parameters for an ultra-trace SF6 detection method utilizing minimal customizations of the analytical instrument are detailed. A method for the detection of parts per trillion (ppt) level concentrations of SF6 for the purpose of underground ventilation tracer gas analysis was successfully developed in this study. The method utilized a Shimadzu gas chromatography with negative ion chemical ionization mass spectrometry system equipped with an Agilent J&W HP-porous layer open tubular column coated with an alumina oxide (Al2O3) S column. The method detection limit (MDL) analysis as defined by the Environmental Protection Agency of the tracer data showed the method MDL to be 5.2 ppt. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Parametric Method to Define Area of Allowable Configurations while Changing Position of Restricted Zones

NASA Astrophysics Data System (ADS)

Pritykin, F. N.; Nefedov, D. I.; Rogoza, Yu A.; Zinchenko, Yu V.

2018-03-01

The article presents the findings related to the development of the module for automatic collision detection of the manipulator with restricted zones for virtual motion modeling. It proposes the parametric method for specifying the area of allowable joint configurations. The authors study the cases when restricted zones are specified using the horizontal plane or front-projection planes. The joint coordinate space is specified by rectangular axes in the direction of which the angles defining the displacements in turning pairs are laid off. The authors present the results of modeling which enabled to develop a parametric method for specifying a set of cross-sections defining the shape and position of allowable configurations in different positions of a restricted zone. All joint points that define allowable configurations refer to the indicated sections. The area of allowable configurations is specified analytically by using several kinematic surfaces that limit it. A geometric analysis is developed based on the use of the area of allowable configurations characterizing the position of the manipulator and reported restricted zones. The paper presents numerical calculations related to virtual simulation of the manipulator path performed by the mobile robot Varan when using the developed algorithm and restricted zones. The obtained analytical dependencies allow us to define the area of allowable configurations, which is a knowledge pool to ensure the intelligent control of the manipulator path in a predefined environment. The use of the obtained region to synthesize a joint trajectory makes it possible to correct the manipulator path to foresee and eliminate deadlocks when synthesizing motions along the velocity vector.

Laser Diagnostics for Reacting Flows

DTIC Science & Technology

2010-01-11

noise characteristics of the diagnostic will be in the shot - noise limit , a fundamental limit of the LIF signal intensity... noise related to the discrete nature of photons. In the shot - noise limit , the fluctuation detection limit can be predicted using nVP B S f f  1...detection limit was shot - noise limited . Figure 2.2.3 illustrates the fluctuation detection limits for line LIF imaging. Figure 2.2.3a

Expert and crowd-sourced validation of an individualized sleep spindle detection method employing complex demodulation and individualized normalization

PubMed Central

Ray, Laura B.; Sockeel, Stéphane; Soon, Melissa; Bore, Arnaud; Myhr, Ayako; Stojanoski, Bobby; Cusack, Rhodri; Owen, Adrian M.; Doyon, Julien; Fogel, Stuart M.

2015-01-01

A spindle detection method was developed that: (1) extracts the signal of interest (i.e., spindle-related phasic changes in sigma) relative to ongoing “background” sigma activity using complex demodulation, (2) accounts for variations of spindle characteristics across the night, scalp derivations and between individuals, and (3) employs a minimum number of sometimes arbitrary, user-defined parameters. Complex demodulation was used to extract instantaneous power in the spindle band. To account for intra- and inter-individual differences, the signal was z-score transformed using a 60 s sliding window, per channel, over the course of the recording. Spindle events were detected with a z-score threshold corresponding to a low probability (e.g., 99th percentile). Spindle characteristics, such as amplitude, duration and oscillatory frequency, were derived for each individual spindle following detection, which permits spindles to be subsequently and flexibly categorized as slow or fast spindles from a single detection pass. Spindles were automatically detected in 15 young healthy subjects. Two experts manually identified spindles from C3 during Stage 2 sleep, from each recording; one employing conventional guidelines, and the other, identifying spindles with the aid of a sigma (11–16 Hz) filtered channel. These spindles were then compared between raters and to the automated detection to identify the presence of true positives, true negatives, false positives and false negatives. This method of automated spindle detection resolves or avoids many of the limitations that complicate automated spindle detection, and performs well compared to a group of non-experts, and importantly, has good external validity with respect to the extant literature in terms of the characteristics of automatically detected spindles. PMID:26441604

Calculation of the detection limits for radionuclides identified in gamma-ray spectra based on post-processing peak analysis results.

PubMed

Korun, M; Vodenik, B; Zorko, B

2018-03-01

A new method for calculating the detection limits of gamma-ray spectrometry measurements is presented. The method is applicable for gamma-ray emitters, irrespective of the influences of the peaked background, the origin of the background and the overlap with other peaks. It offers the opportunity for multi-gamma-ray emitters to calculate the common detection limit, corresponding to more peaks. The detection limit is calculated by approximating the dependence of the uncertainty in the indication on its value with a second-order polynomial. In this approach the relation between the input quantities and the detection limit are described by an explicit expression and can be easy investigated. The detection limit is calculated from the data usually provided by the reports of peak-analyzing programs: the peak areas and their uncertainties. As a result, the need to use individual channel contents for calculating the detection limit is bypassed. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Unsupervised kNN Method to Systematically Detect Changes in Protein Localization in High-Throughput Microscopy Images.

PubMed

Lu, Alex Xijie; Moses, Alan M

2016-01-01

Despite the importance of characterizing genes that exhibit subcellular localization changes between conditions in proteome-wide imaging experiments, many recent studies still rely upon manual evaluation to assess the results of high-throughput imaging experiments. We describe and demonstrate an unsupervised k-nearest neighbours method for the detection of localization changes. Compared to previous classification-based supervised change detection methods, our method is much simpler and faster, and operates directly on the feature space to overcome limitations in needing to manually curate training sets that may not generalize well between screens. In addition, the output of our method is flexible in its utility, generating both a quantitatively ranked list of localization changes that permit user-defined cut-offs, and a vector for each gene describing feature-wise direction and magnitude of localization changes. We demonstrate that our method is effective at the detection of localization changes using the Δrpd3 perturbation in Saccharomyces cerevisiae, where we capture 71.4% of previously known changes within the top 10% of ranked genes, and find at least four new localization changes within the top 1% of ranked genes. The results of our analysis indicate that simple unsupervised methods may be able to identify localization changes in images without laborious manual image labelling steps.

Diagnostic value of highly-sensitive chimerism analysis after allogeneic stem cell transplantation.

PubMed

Sellmann, Lea; Rabe, Kim; Bünting, Ivonne; Dammann, Elke; Göhring, Gudrun; Ganser, Arnold; Stadler, Michael; Weissinger, Eva M; Hambach, Lothar

2018-05-02

Conventional analysis of host chimerism (HC) frequently fails to detect relapse before its clinical manifestation in patients with hematological malignancies after allogeneic stem cell transplantation (allo-SCT). Quantitative PCR (qPCR)-based highly-sensitive chimerism analysis extends the detection limit of conventional (short tandem repeats-based) chimerism analysis from 1 to 0.01% host cells in whole blood. To date, the diagnostic value of highly-sensitive chimerism analysis is hardly defined. Here, we applied qPCR-based chimerism analysis to 901 blood samples of 71 out-patients with hematological malignancies after allo-SCT. Receiver operating characteristics (ROC) curves were calculated for absolute HC values and for the increments of HC before relapse. Using the best cut-offs, relapse was detected with sensitivities of 74 or 85% and specificities of 69 or 75%, respectively. Positive predictive values (PPVs) were only 12 or 18%, but the respective negative predictive values were 98 or 99%. Relapse was detected median 38 or 45 days prior to clinical diagnosis, respectively. Considering also durations of steadily increasing HC of more than 28 days improved PPVs to more than 28 or 59%, respectively. Overall, highly-sensitive chimerism analysis excludes relapses with high certainty and predicts relapses with high sensitivity and specificity more than a month prior to clinical diagnosis.

A Comparative Survey of Methods for Remote Heart Rate Detection From Frontal Face Videos

PubMed Central

Wang, Chen; Pun, Thierry; Chanel, Guillaume

2018-01-01

Remotely measuring physiological activity can provide substantial benefits for both the medical and the affective computing applications. Recent research has proposed different methodologies for the unobtrusive detection of heart rate (HR) using human face recordings. These methods are based on subtle color changes or motions of the face due to cardiovascular activities, which are invisible to human eyes but can be captured by digital cameras. Several approaches have been proposed such as signal processing and machine learning. However, these methods are compared with different datasets, and there is consequently no consensus on method performance. In this article, we describe and evaluate several methods defined in literature, from 2008 until present day, for the remote detection of HR using human face recordings. The general HR processing pipeline is divided into three stages: face video processing, face blood volume pulse (BVP) signal extraction, and HR computation. Approaches presented in the paper are classified and grouped according to each stage. At each stage, algorithms are analyzed and compared based on their performance using the public database MAHNOB-HCI. Results found in this article are limited on MAHNOB-HCI dataset. Results show that extracted face skin area contains more BVP information. Blind source separation and peak detection methods are more robust with head motions for estimating HR. PMID:29765940

Detection of shielded nuclear material in a cargo container

NASA Astrophysics Data System (ADS)

Jones, James L.; Norman, Daren R.; Haskell, Kevin J.; Sterbentz, James W.; Yoon, Woo Y.; Watson, Scott M.; Johnson, James T.; Zabriskie, John M.; Bennett, Brion D.; Watson, Richard W.; Moss, Cavin E.; Frank Harmon, J.

2006-06-01

The Idaho National Laboratory, along with Los Alamos National Laboratory and the Idaho State University's Idaho Accelerator Center, are developing electron accelerator-based, photonuclear inspection technologies for the detection of shielded nuclear material within air-, rail-, and especially, maritime-cargo transportation containers. This paper describes a developing prototypical cargo container inspection system utilizing the Pulsed Photonuclear Assessment (PPA) technology, incorporates interchangeable, well-defined, contraband shielding structures (i.e., "calibration" pallets) providing realistic detection data for induced radiation signatures from smuggled nuclear material, and provides various shielded nuclear material detection results. Using a 4.8-kg quantity of depleted uranium, neutron and gamma-ray detection responses are presented for well-defined shielded and unshielded configurations evaluated in a selected cargo container inspection configuration.

Respiratory Motion Management in PET/CT: Applications and Clinical Usefulness.

PubMed

Guerra, Luca; Ponti, Elena De; Morzenti, Sabrina; Spadavecchia, Chiara; Crivellaro, Cinzia

2017-01-01

Breathing movement can introduce heavy bias in both image quality and quantitation in PET/CT. The aim of this paper is a review of the literature to evaluate the benefit of respiratory gating in terms of image quality, quantification and lesion detectability. A review of the literature published in the last 10 years and dealing with gated PET/CT technique has been performed, focusing on improvement in quantification, lesion detectability and diagnostic accuracy in neoplastic lesion. In addition, the improvement in the definition of radiotherapy planning has been evaluated. There is a consistent increase of the Standardized Uptake Value (SUV) in gated PET images when compared to ungated ones, particularly for lesions located in liver and in lung. Respiratory gating can also increase sensitivity, specificity and accuracy of PET/CT. Gated PET/CT can be used for radiation therapy planning, reducing the uncertainty in target definition, optimizing the volume to be treated and reducing the possibility of "missing" during the dose delivery. Moreover, new technologies, able to define the movement of lesions and organs directly from the PET sinogram, can solve some problems that currently are limiting the clinical use of gated PET/CT (i.e.: extended acquisition time, radiation exposure). The published literature demonstrated that respiratory gating PET/CT is a valid technique to improve quantification, lesion detectability of lung and liver tumors and can better define the radiotherapy planning of moving lesions and organs. If new technical improvements for motion compensation will be clinically validated, gated technique could be applied routinely in any PET/CT scan. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A patient self-collection method for longitudinal monitoring of respiratory virus infection in solid organ transplant recipients.

PubMed

Preiksaitis, Carl M; Kuypers, Jane M; Fisher, Cynthia E; Campbell, Angela P; Jerome, Keith R; Huang, Meei-Li; Boeckh, Michael; Limaye, Ajit P

2015-01-01

Methods for the longitudinal study of respiratory virus infections are cumbersome and limit our understanding of the natural history of these infections in solid organ transplant (SOT) recipients. To assess the feasibility and patient acceptability of self-collected foam nasal swabs for detection of respiratory viruses in SOT recipients and to define the virologic and clinical course. We prospectively monitored the course of symptomatic respiratory virus infection in 18 SOT patients (14 lung, 3 liver, and 1 kidney) using patient self-collected swabs. The initial study sample was positive in 15 patients with the following respiratory viruses: rhinovirus (6), metapneumovirus (1), coronavirus (2), respiratory syncytial virus (2), parainfluenza virus (2), and influenza A virus (2). One hundred four weekly self-collected nasal swabs were obtained, with a median of 4 samples per patient (range 1-17). Median duration of viral detection was 21 days (range 4-77 days). Additional new respiratory viruses detected during follow-up of these 15 patients included rhinovirus (3), metapneumovirus (2), coronavirus (1), respiratory syncytial virus (1), parainfluenza virus (1), and adenovirus (1). Specimen collection compliance was good; 16/18 (89%) patients collected all required specimens and 79/86 (92%) follow-up specimens were obtained within the 7 ± 3 day protocol-defined window. All participants agreed or strongly agreed that the procedure was comfortable, simple, and 13/14 (93%) were willing to participate in future studies using this procedure. Self-collected nasal swabs provide a convenient, feasible, and patient-acceptable methodology for longitudinal monitoring of upper respiratory virus infection in SOT recipients. Copyright © 2014 Elsevier B.V. All rights reserved.

Automatic Detection and Classification of Unsafe Events During Power Wheelchair Use.

PubMed

Pineau, Joelle; Moghaddam, Athena K; Yuen, Hiu Kim; Archambault, Philippe S; Routhier, François; Michaud, François; Boissy, Patrick

2014-01-01

Using a powered wheelchair (PW) is a complex task requiring advanced perceptual and motor control skills. Unfortunately, PW incidents and accidents are not uncommon and their consequences can be serious. The objective of this paper is to develop technological tools that can be used to characterize a wheelchair user's driving behavior under various settings. In the experiments conducted, PWs are outfitted with a datalogging platform that records, in real-time, the 3-D acceleration of the PW. Data collection was conducted over 35 different activities, designed to capture a spectrum of PW driving events performed at different speeds (collisions with fixed or moving objects, rolling on incline plane, and rolling across multiple types obstacles). The data was processed using time-series analysis and data mining techniques, to automatically detect and identify the different events. We compared the classification accuracy using four different types of time-series features: 1) time-delay embeddings; 2) time-domain characterization; 3) frequency-domain features; and 4) wavelet transforms. In the analysis, we compared the classification accuracy obtained when distinguishing between safe and unsafe events during each of the 35 different activities. For the purposes of this study, unsafe events were defined as activities containing collisions against objects at different speed, and the remainder were defined as safe events. We were able to accurately detect 98% of unsafe events, with a low (12%) false positive rate, using only five examples of each activity. This proof-of-concept study shows that the proposed approach has the potential of capturing, based on limited input from embedded sensors, contextual information on PW use, and of automatically characterizing a user's PW driving behavior.

Mass Spectrometry Strategies for Clinical Metabolomics and Lipidomics in Psychiatry, Neurology, and Neuro-Oncology

PubMed Central

Wood, Paul L

2014-01-01

Metabolomics research has the potential to provide biomarkers for the detection of disease, for subtyping complex disease populations, for monitoring disease progression and therapy, and for defining new molecular targets for therapeutic intervention. These potentials are far from being realized because of a number of technical, conceptual, financial, and bioinformatics issues. Mass spectrometry provides analytical platforms that address the technical barriers to success in metabolomics research; however, the limited commercial availability of analytical and stable isotope standards has created a bottleneck for the absolute quantitation of a number of metabolites. Conceptual and financial factors contribute to the generation of statistically under-powered clinical studies, whereas bioinformatics issues result in the publication of a large number of unidentified metabolites. The path forward in this field involves targeted metabolomics analyses of large control and patient populations to define both the normal range of a defined metabolite and the potential heterogeneity (eg, bimodal) in complex patient populations. This approach requires that metabolomics research groups, in addition to developing a number of analytical platforms, build sufficient chemistry resources to supply the analytical standards required for absolute metabolite quantitation. Examples of metabolomics evaluations of sulfur amino-acid metabolism in psychiatry, neurology, and neuro-oncology and of lipidomics in neurology will be reviewed. PMID:23842599

Treatment outcomes in patients with third-generation cephalosporin-resistant Enterobacter bacteremia.

PubMed

O'Neal, Catherine S; O'Neal, Hollis R; Daniels, Titus L; Talbot, Thomas R

2012-10-01

Infections with resistant Enterobacter spp. are increasingly described, yet data on outcomes associated with these infections are limited. A retrospective cohort study was conducted to investigate outcomes of hospitalized patients with third-generation cephalosporin-resistant (CR) Enterobacter bacteremia. Cephalosporin resistance was detected using cefotaxime and cefpodoxime. Patients with Enterobacter spp. bacteremia from January 2006 through February 2008 defined the population. We defined cases as those with CR isolates; controls were patients with bacteremia due to non-CR isolates. Treatment failure was defined as persistence of the presenting signs of infection 72 h after initial culture collection. Of the 95 Enterobacter cases identified, 31 (33%) were CR. CR cases were significantly associated with treatment failure (odds ratio (OR) 2.81, 95% confidence interval (CI) 1.14-6.94). This association was not seen after adjustment for age, simplified acute physiology score (SAPS II), and inappropriate empiric antibiotic therapy. Inappropriate empiric therapy (adjusted OR 3.86, 95% CI 1.32-11.31) and SAPS II score (adjusted OR 1.09, 95% CI 1.02-1.16) were significantly associated with treatment failure in the multivariate analysis. Third-generation cephalosporin-resistant Enterobacter bacteremia is associated with treatment failure due to receipt of inappropriate empiric antibiotic therapy and severity of illness.

Mass spectrometry strategies for clinical metabolomics and lipidomics in psychiatry, neurology, and neuro-oncology.

PubMed

Wood, Paul L

2014-01-01

Metabolomics research has the potential to provide biomarkers for the detection of disease, for subtyping complex disease populations, for monitoring disease progression and therapy, and for defining new molecular targets for therapeutic intervention. These potentials are far from being realized because of a number of technical, conceptual, financial, and bioinformatics issues. Mass spectrometry provides analytical platforms that address the technical barriers to success in metabolomics research; however, the limited commercial availability of analytical and stable isotope standards has created a bottleneck for the absolute quantitation of a number of metabolites. Conceptual and financial factors contribute to the generation of statistically under-powered clinical studies, whereas bioinformatics issues result in the publication of a large number of unidentified metabolites. The path forward in this field involves targeted metabolomics analyses of large control and patient populations to define both the normal range of a defined metabolite and the potential heterogeneity (eg, bimodal) in complex patient populations. This approach requires that metabolomics research groups, in addition to developing a number of analytical platforms, build sufficient chemistry resources to supply the analytical standards required for absolute metabolite quantitation. Examples of metabolomics evaluations of sulfur amino-acid metabolism in psychiatry, neurology, and neuro-oncology and of lipidomics in neurology will be reviewed.

Landmark-based deep multi-instance learning for brain disease diagnosis.

PubMed

Liu, Mingxia; Zhang, Jun; Adeli, Ehsan; Shen, Dinggang

2018-01-01

In conventional Magnetic Resonance (MR) image based methods, two stages are often involved to capture brain structural information for disease diagnosis, i.e., 1) manually partitioning each MR image into a number of regions-of-interest (ROIs), and 2) extracting pre-defined features from each ROI for diagnosis with a certain classifier. However, these pre-defined features often limit the performance of the diagnosis, due to challenges in 1) defining the ROIs and 2) extracting effective disease-related features. In this paper, we propose a landmark-based deep multi-instance learning (LDMIL) framework for brain disease diagnosis. Specifically, we first adopt a data-driven learning approach to discover disease-related anatomical landmarks in the brain MR images, along with their nearby image patches. Then, our LDMIL framework learns an end-to-end MR image classifier for capturing both the local structural information conveyed by image patches located by landmarks and the global structural information derived from all detected landmarks. We have evaluated our proposed framework on 1526 subjects from three public datasets (i.e., ADNI-1, ADNI-2, and MIRIAD), and the experimental results show that our framework can achieve superior performance over state-of-the-art approaches. Copyright © 2017 Elsevier B.V. All rights reserved.

Simple and rapid fabrication of disposable carbon-based electrochemical cells using an electronic craft cutter for sensor and biosensor applications.

PubMed

Afonso, André S; Uliana, Carolina V; Martucci, Diego H; Faria, Ronaldo C

2016-01-01

This work describes the construction of an all-plastic disposable carbon-based electrochemical cell (DCell) using a simple procedure based on the use of a home cutter printer for prototyping and laminating. The cutter printer and adhesive vinyl films were used to produce three electrodes in an electrochemical cell layout, and a laminating process was then used to define the geometric area and insulate the electrodes. The DCell showed excellent performance in several applications including the determination of toxic metals in water samples, the immobilization of DNA and the detection of Salmonella. An unmodified DCell was applied for Pb and Cd detection in the range of 100-300 ng mL(-1) with a limit of detection of 50 and 39 ng mL(-1) for Cd and Pb, respectively. DNA was successfully immobilized on a DCell and used for studies of interaction between bisphenol A and DNA. The square wave voltammetry of a DNA modified DCell presented a guanine oxidation current 2.5 times greater after exposure of the electrode to bisphenol A and no current variation for the adenine moiety indicating that bisphenol A showed a preference for DNA interaction sites. A magneto-immunoassay was developed using a DCell for Salmonella detection in milk samples. The system presented a linear range from 100 to 700 cells mL(-1) with a limit of detection of 100 cells mL(-1) and good recovery values between 93% and 101% in milk samples, with no interference from Escherichia coli. Using the proposed method, hundreds of DCells can be assembled in less than two hours, at a material cost of less than US $0.02 per cell. The all-plastic disposable electrochemical cell developed was successfully applied as an electrochemical sensor and biosensor. The feasibility of the developed all-plastic disposable electrochemical cell was demonstrated in applications as both sensor and biosensor. Copyright © 2015 Elsevier B.V. All rights reserved.

A test strip platform based on DNA-functionalized gold nanoparticles for on-site detection of mercury (II) ions.

PubMed

Guo, Zhiyong; Duan, Jing; Yang, Fei; Li, Min; Hao, Tingting; Wang, Sui; Wei, Danyi

2012-05-15

A test strip, based on DNA-functionalized gold nanoparticles for Hg(2+) detection, has been developed, optimized and validated. The developed colorimetric mercury sensor system exhibited a highly sensitive and selective response to mercury. The measurement principle is based on thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and streptavidin-biotin interaction. A biotin-labeled and thiolated DNA was immobilized on the gold nanoparticles (AuNPs) surface through a self-assembling method. Another thymine-rich DNA, which was introduced to form DNA duplexes on the AuNPs surface with thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination in the presence of Hg(2+), was immobilized on the nitrocellulose membrane as the test zone. When Hg(2+) ions were introduced into this system, they induced the two strands of DNA to intertwist by forming T-Hg(2+)-T bonds resulting in a red line at the test zone. The biotin-labeled and thiolated DNA-functionalized AuNPs could be captured by streptavidin which was immobilized on the nitrocellulose membrane as the control zone. Under optimized conditions, the detection limit for Hg(2+) was 3 nM, which is lower than the 10nM, maximum contaminant limit defined by the US Environmental Protection Agency (EPA) for drinking water. A parallel analysis of Hg(2+) in pool water samples using cold vapor atomic absorption spectrometry showed comparable results to those obtained from the strip test. Therefore, the results obtained in this study could be used as basic research for the development of Hg(2+) detection, and the method developed could be a potential on-site screening tool for the rapid detection of Hg(2+) in different water samples without special instrumentation. All experimental variables that influence the test strip response were optimized and reported. Copyright © 2012 Elsevier B.V. All rights reserved.

Methods for Combining Payload Parameter Variations with Input Environment

NASA Technical Reports Server (NTRS)

Merchant, D. H.; Straayer, J. W.

1975-01-01

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occuring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular value of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the methods are also presented.

Practical and regenerable electrochemical aptasensor based on nanoporous gold and thymine-Hg2+-thymine base pairs for Hg2+ detection.

PubMed

Zeng, Guangming; Zhang, Chen; Huang, Danlian; Lai, Cui; Tang, Lin; Zhou, Yaoyu; Xu, Piao; Wang, Hou; Qin, Lei; Cheng, Min

2017-04-15

A simple, practical and reusable electrochemical aptasensor, based on thymine-Hg 2+ -thymine (T-Hg 2+ -T) coordination chemistry and nanoporous gold (NPG) for signal amplification, was designed for sensitive and selective detection of mercury ions (Hg 2+ ). The thiol modified T-rich hairpin capture probe was self-assembled onto the surface of the NPG modified electrode for hybridizing with ferrocene-labeled T-rich probe in the presence of Hg 2+ via T-Hg 2+ -T coordination chemistry. As a result, the hairpin capture probe was opened, and the ferrocene tags were close to the NPG modified electrode. Taking advantage of the amplification effect of NPG electrode for increasing the reaction sites of thiol modified capture probe, the proposed electrochemical aptasensor could detect Hg 2+ quantitatively in the range of 0.01-5000nM, with a detection limit as low as 0.0036nM which is much lower than the maximum contamination level for Hg 2+ in drinking water defined by the U.S. Environmental Protection Agency. Moreover, the proposed electrochemical aptasensor can be regenerated by adding cysteine and Mg 2+ . The aptasensor was also used to detect Hg 2+ from real water samples, and the results showed excellent agreement with the values determined by atomic fluorescence spectrometer. This aptasensor showed a promising potential for on-site detecting Hg 2+ in drinking water. Copyright © 2016 Elsevier B.V. All rights reserved.

Where and When: Optimal Scheduling of the Electromagnetic Follow-up of Gravitational-wave Events Based on Counterpart Light-curve Models

NASA Astrophysics Data System (ADS)

Salafia, Om Sharan; Colpi, Monica; Branchesi, Marica; Chassande-Mottin, Eric; Ghirlanda, Giancarlo; Ghisellini, Gabriele; Vergani, Susanna D.

2017-09-01

The electromagnetic (EM) follow-up of a gravitational-wave (GW) event requires scanning a wide sky region, defined by the so-called “skymap,” to detect and identify a transient counterpart. We propose a novel method that exploits the information encoded in the GW signal to construct a “detectability map,” which represents the time-dependent (“when”) probability of detecting the transient at each position of the skymap (“where”). Focusing on the case of a neutron star binary inspiral, we model the associated short gamma-ray burst afterglow and macronova emission using the probability distributions of binary parameters (sky position, distance, orbit inclination, mass ratio) extracted from the GW signal as inputs. The resulting family of possible light curves is the basis for constructing the detectability map. As a practical example, we apply the method to a simulated GW signal produced by a neutron star merger at 75 Mpc whose localization uncertainty is very large (˜1500 deg2). We construct observing strategies for optical, infrared, and radio facilities based on the detectability maps, taking VST, VISTA, and MeerKAT as prototypes. Assuming limiting fluxes of r˜ 24.5, J˜ 22.4 (AB magnitudes), and 500 μ {Jy} (1.4 {GHz}) for ˜1000 s of exposure each, the afterglow and macronova emissions are successfully detected with a minimum observing time of 7, 15, and 5 hr respectively.

Automated detection of periventricular veins on 7 T brain MRI

NASA Astrophysics Data System (ADS)

Kuijf, Hugo J.; Bouvy, Willem H.; Zwanenburg, Jaco J. M.; Viergever, Max A.; Biessels, Geert Jan; Vincken, Koen L.

2015-03-01

Cerebral small vessel disease is common in elderly persons and a leading cause of cognitive decline, dementia, and acute stroke. With the introduction of ultra-high field strength 7.0T MRI, it is possible to visualize small vessels in the brain. In this work, a proof-of-principle study is conducted to assess the feasibility of automatically detecting periventricular veins. Periventricular veins are organized in a fan-pattern and drain venous blood from the brain towards the caudate vein of Schlesinger, which is situated along the lateral ventricles. Just outside this vein, a region-of- interest (ROI) through which all periventricular veins must cross is defined. Within this ROI, a combination of the vesselness filter, tubular tracking, and hysteresis thresholding is applied to locate periventricular veins. All detected locations were evaluated by an expert human observer. The results showed a positive predictive value of 88% and a sensitivity of 95% for detecting periventricular veins. The proposed method shows good results in detecting periventricular veins in the brain on 7.0T MR images. Compared to previous works, that only use a 1D or 2D ROI and limited image processing, our work presents a more comprehensive definition of the ROI, advanced image processing techniques to detect periventricular veins, and a quantitative analysis of the performance. The results of this proof-of-principle study are promising and will be used to assess periventricular veins on 7.0T brain MRI.

A face in a (temporal) crowd.

PubMed

Hacker, Catrina M; Meschke, Emily X; Biederman, Irving

2018-03-20

Familiar objects, specified by name, can be identified with high accuracy when embedded in a rapidly presented sequence of images at rates exceeding 10 images/s. Not only can target objects be detected at such brief presentation rates, they can also be detected under high uncertainty, where their classification is defined negatively, e.g., "Not a Tool." The identification of a familiar speaker's voice declines precipitously when uncertainty is increased from one to a mere handful of possible speakers. Is the limitation imposed by uncertainty, i.e., the number of possible individuals, a general characteristic of processes for person individuation such that the identifiability of a familiar face would undergo a similar decline with uncertainty? Specifically, could the presence of an unnamed celebrity, thus any celebrity, be detected when presented in a rapid sequence of unfamiliar faces? If so, could the celebrity be identified? Despite the markedly greater physical similarity of faces compared to objects that are, say, not tools, the presence of a celebrity could be detected with moderately high accuracy (∼75%) at rates exceeding 7 faces/s. False alarms were exceedingly rare as almost all the errors were misses. Detection accuracy by moderate congenital prosopagnosics was lower than controls, but still well above chance. Given the detection of the presence of a celebrity, all subjects were almost always able to identify that celebrity, providing no role for a covert familiarity signal outside of awareness. Copyright © 2018 Elsevier Ltd. All rights reserved.

White matter microstructure and cognitive decline in metabolic syndrome: a review of diffusion tensor imaging.

PubMed

Alfaro, Freddy J; Gavrieli, Anna; Saade-Lemus, Patricia; Lioutas, Vasileios-Arsenios; Upadhyay, Jagriti; Novak, Vera

2018-01-01

Metabolic syndrome is a cluster of cardiovascular risk factors defined by the presence of abdominal obesity, glucose intolerance, hypertension and/or dyslipidemia. It is a major public health epidemic worldwide, and a known risk factor for the development of cognitive dysfunction and dementia. Several studies have demonstrated a positive association between the presence of metabolic syndrome and worse cognitive outcomes, however, evidence of brain structure pathology is limited. Diffusion tensor imaging has offered new opportunities to detect microstructural white matter changes in metabolic syndrome, and a possibility to detect associations between functional and structural abnormalities. This review analyzes the impact of metabolic syndrome on white matter microstructural integrity, brain structure abnormalities and their relationship to cognitive function. Each of the metabolic syndrome components exerts a specific signature of white matter microstructural abnormalities. Metabolic syndrome and its components exert both additive/synergistic, as well as, independent effects on brain microstructure thus accelerating brain aging and cognitive decline. Copyright © 2017 Elsevier Inc. All rights reserved.

Optical Coherence Tomography Angiography Features of Diabetic Retinopathy

PubMed Central

Hwang, Thomas S.; Jia, Yali; Gao, Simon S.; Bailey, Steven T.; Lauer, Andreas K.; Flaxel, Christina J.; Wilson, David J.; Huang, David

2015-01-01

Purpose To describe the optical coherence tomography (OCT) angiography features of diabetic retinopathy Methods Using a 70kHz OCT and the split-spectrum amplitude decorrelation angiography (SSADA) algorithm, 6 × 6 mm 3-dimensional angiograms of the macula of 4 patients with diabetic retinopathy were obtained and compared with fluorescein angiography (FA) for features catalogued by the Early Treatment of Diabetic Retinopathy Study. Results OCT angiography detected enlargement and distortion of the foveal avascular zone, retinal capillary dropout, and pruning of arteriolar branches. Areas of capillary loss obscured by fluorescein leakage on FA were more clearly defined on OCT angiography. Some areas of focal leakage on FA that were thought to be microaneurysms were found to be small tufts of neovascularization that extended above the inner limiting membrane. Conclusion OCT angiography does not show leakage, but can better delineate areas of capillary dropout and detect early retinal neovascularization. This new noninvasive angiography technology may be useful for routine surveillance of proliferative and ischemic changes in diabetic retinopathy. PMID:26308529

Red-emitting fluorescent probe for detecting hypochlorite acid in vitro and in vivo.

PubMed

Chen, Hong; Sun, Tao; Qiao, Xiao-Guang; Tang, Qian-Oian; Zhao, Shan-Chao; Zhou, Zhan

2018-06-12

Due to the importance of hypochlorous acid (HClO) in biological and industrial, development of fluorescent probes for HClO has been an active research area. Here, a new red-emitting ratiometric fluorescent probe (P) was synthesized and well defined characterization via NMR, HR-MS, and fluorescence spectrum, which serves as a selective and sensitive probe for ClO - group. The probe showed a ratiometric fluorescent response to hypochlorite at the emission intensities ratio (I 480 /I 612 ) increasing from 0.28 to 27.46. The emission intensities ratio (I 480 /I 612 ) was linearly enhanced (I 480 /I 612  = 0.064 X + 0.096) with the ClO - concentration range from 1 to 30 μM. The detection limitation for ClO - in aqueous solution is 0.47 μM. Moreover, this biocompatible red-emitting ratiometric fluorescent probe was utilized to the fluorescence imaging of ClO - in living cells and Zebrafish. Copyright © 2018. Published by Elsevier B.V.

Intrusion Detection: Generics and State-of-the-Art (la Detection de l’intrusion: Modeles generiques et etat de l’art)

DTIC Science & Technology

2002-01-01

by the user for a number of possible pre-defined intrusions. One of these pre-defined intrusions is the command “get /etc/ passwd ”. If this command is...Application-level firewalls: which check communication at the application level. An example is the string get /etc/ passwd in the ftp protocol

Development of a simple screening tool for opportunistic COPD case finding in primary care in Latin America: The PUMA study.

PubMed

López Varela, Maria Victorina; Montes de Oca, Maria; Rey, Alejandra; Casas, Alejandro; Stirbulov, Roberto; Di Boscio, Valentina

2016-10-01

Opportunistic chronic obstructive pulmonary disease (COPD) case finding approaches for high-risk individuals with or without symptoms is a feasible option for disease identification. PUMA is an opportunistic case finding study conducted in primary care setting of Argentina, Colombia, Venezuela and Uruguay. The objectives were to measure COPD prevalence in an at-risk population visiting primary care for any reason, to assess the yield of this opportunistic approach and the accuracy of a score developed to detect COPD. Subjects attending routine primary care visits, ≥40 years of age, current or former smokers or exposed to biomass smoke, completed a questionnaire and performed spirometry. COPD was defined as post-bronchodilator (post-BD) forced expiratory volume in 1 s (FEV1 )/forced vital capacity (FVC) < 0.70 and the lower limit of normal of FEV1 /FVC. A total of 1743 subjects completed the interview; 1540 performed acceptable spirometry. COPD prevalence was 20.1% (n = 309; ranging from 11.0% in Venezuela to 29.6% in Argentina) when defined using post-BD FEV1 /FVC < 0.70, and 14.7% (n = 226; ranging from 8.3% in Venezuela to 21.8% in Colombia) using the lower limit of normal. Logistic regression analysis for both definitions showed that the risk of COPD was significantly higher for persons >50 years, heavy smokers (>30 pack-years), with dyspnoea, and having prior spirometry. A simple score and a weighted score constructed using the following predictive factors: gender, age, pack-years smoking, dyspnoea, sputum, cough and spirometry, had a mean accuracy for detecting COPD (post-BD FEV1 /FVC < 0.70) of 76% and 79% for the simple and weighted scores, respectively. This simple seven-item score is an accurate screening tool to select subjects for spirometry in primary care. © 2016 Asian Pacific Society of Respirology.

Wire-chamber radiation detector with discharge control

DOEpatents

Perez-Mendez, V.; Mulera, T.A.

1982-03-29

A wire chamber; radiation detector has spaced apart parallel electrodes and grids defining an ignition region in which charged particles or other ionizing radiations initiate brief localized avalanche discharges and defining an adjacent memory region in which sustained glow discharges are initiated by the primary discharges. Conductors of the grids at each side of the memory section extend in orthogonal directions enabling readout of the X-Y coordinates of locations at which charged particles were detected by sequentially transmitting pulses to the conductors of one grid while detecting transmissions of the pulses to the orthogonal conductors of the other grid through glow discharges. One of the grids bounding the memory region is defined by an array of conductive elements each of which is connected to the associated readout conductor through a separate resistance. The wire chamber avoids ambiguities and imprecisions in the readout of coordinates when large numbers of simultaneous or; near simultaneous charged particles have been detected. Down time between detection periods and the generation of radio frequency noise are also reduced.

Full Viral Suppression, Low-Level Viremia, and Quantifiable Plasma HIV-RNA at the End of Pregnancy in HIV-Infected Women on Antiretroviral Treatment.

PubMed

Baroncelli, Silvia; Pirillo, Maria F; Tamburrini, Enrica; Guaraldi, Giovanni; Pinnetti, Carmela; Degli Antoni, Anna; Galluzzo, Clementina M; Stentarelli, Chiara; Amici, Roberta; Floridia, Marco

2015-07-01

There is limited information on full viral suppression and low-level HIV-RNA viremia in HIV-infected women at the end of pregnancy. We investigated HIV-RNA levels close to delivery in women on antiretroviral treatment in order to define rates of complete suppression, low-level viremia, and quantifiable HIV-RNA, exploring as potential determinants some clinical and viroimmunological variables. Plasma samples from a national study in Italy, collected between 2003 and 2012, were used. According to plasma HIV-RNA levels, three groups were defined: full suppression (target not detected), low-level viremia (target detected but <37 copies/ml), and quantifiable HIV-RNA (≥37 copies/ml). Multivariable logistic regression was used to define determinants of full viral suppression and of quantifiable HIV-RNA. Among 107 women evaluated at a median gestational age of 35 weeks, 90 (84.1%) had HIV-RNA <37 copies/ml. Most of them (59/90, 65.6%) had full suppression, with the remaining (31/90, 34.4%) showing low-level viremia (median: 11.9 copies/ml; IQR 7.4-16.3). Among the 17 women with quantifiable viral load, median HIV-RNA was 109 copies/ml (IQR 46-251), with only one case showing resistance (mutation M184V; rate: 9.1%). In multivariable analyses, women with higher baseline HIV-RNA levels and with hepatitis C virus (HCV) coinfection were significantly more likely to have quantifiable HIV-RNA in late pregnancy. Full viral suppression was significantly more likely with nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens and significantly less likely with higher HIV-RNA in early pregnancy. No cases of HIV transmission occurred. In conclusion, HIV-infected pregnant women showed a high rate of viral suppression and a low resistance rate before delivery. In most cases no target HIV-RNA was detected in plasma, suggesting a low risk of subsequent virological rebound and development of resistance. Women with high levels of HIV-RNA in early pregnancy and those who have concomitant HCV infection should be considered at higher risk of having quantifiable HIV-RNA at the end of pregnancy.

ARM-microcontroller based portable nitrite electrochemical analyzer using cytochrome c reductase biofunctionalized onto screen printed carbon electrode.

PubMed

Santharaman, Paulraj; Venkatesh, Krishna Arun; Vairamani, Kanagavel; Benjamin, Alby Robson; Sethy, Niroj K; Bhargava, Kalpana; Karunakaran, Chandran

2017-04-15

Nitrite (NO 2 - ) supplementation limits hypoxia-induced oxidative stress and activates the alternate NO pathway which may partially account for the nitrite-mediated cardioprotection. So, sensitive and selective biosensors with point-of-care devices need to be explored to detect the physiological nitrite level due to its important role in human pathophysiology. In this work, cytochrome c reductase (CcR) biofunctionalized self assembled monolayer (SAM) functionalized on gold nanoparticles (GNPs) in polypyrrole (PPy) nanocomposite onto the screen printed carbon electrode (SPCE) was investigated as a biosensor for the detection of nitrite based on its electrochemical and catalytic properties. CcR was covalently coupled with SAM layers on GNPs by using EDC and NHS. Direct electrochemical response of CcR biofunctionalized electrodes showed a couple of well-defined and nearly reversible cyclic voltammetric peaks at -0.34 and -0.45 vs. Ag/AgCl. Under optimal conditions, the biosensor could be used for the determination of NO 2 - with a linear range from 0.1-1600µm and a detection limit of 60nM with a sensitivity of 0.172µAµM -1 cm -2 . Further, we have designed and developed a novel and cost effective portable electrochemical analyzer for the measurement of NO 2 - in hypoxia induced H9c2 cardiac cells using ARM microcontroller. The results obtained here using the developed portable electrochemical nitrite analyzer were also compared with the standard cyclic voltammetry instrument and found in agreement with each other. Copyright © 2016 Elsevier B.V. All rights reserved.

Role of imaging and biopsy to assess local recurrence after definitive treatment for prostate carcinoma (surgery, radiotherapy, cryotherapy, HIFU).

PubMed

Martino, Pasquale; Scattoni, Vincenzo; Galosi, Andrea B; Consonni, Paolo; Trombetta, Carlo; Palazzo, Silvano; Maccagnano, Carmen; Liguori, Giovanni; Valentino, Massimo; Battaglia, Michele; Barozzi, Libero

2011-10-01

Defining the site of recurrent disease early after definitive treatment for a localized prostate cancer is a critical issue as it may greatly influence the subsequent therapeutic strategy or patient management. A systematic review of the literature was performed by searching Medline from January 1995 up to January 2011. Electronic searches were limited to the English language, and the keywords prostate cancer, radiotherapy [RT], high intensity focused ultrasound [HIFU], cryotherapy [CRIO], transrectal ultrasound [TRUS], magnetic resonance [MRI], PET/TC, and prostate biopsy were used. Despite the fact that diagnosis of a local recurrence is based on PSA values and kinetics, imaging by means of different techniques may be a prerequisite for effective disease management. Unfortunately, prostate cancer local recurrences are very difficult to detect by TRUS and conventional imaging that have shown limited accuracy at least at early stages. On the contrary, functional and molecular imaging such as dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI), offers the possibility of imaging molecular or cellular processes of individual tumors. Recently, PET/CT, using 11C-choline, 18F-fluorocholine or 11C-acetate has been successfully proposed in detecting local recurrences as well as distant metastases. Nevertheless, in controversial cases, it is necessary to perform a biopsy of the prostatic fossa or a biopsy of the prostate to assess the presence of a local recurrence under guidance of MRI or TRUS findings. It is likely that imaging will be extensively used in the future to detect and localize prostate cancer local recurrences before salvage treatment.

Investigating bacterial populations in styrene-degrading biofilters by 16S rDNA tag pyrosequencing.

PubMed

Portune, Kevin J; Pérez, M Carmen; Álvarez-Hornos, F Javier; Gabaldón, Carmen

2015-01-01

Microbial biofilms are essential components in the elimination of pollutants within biofilters, yet still little is known regarding the complex relationships between microbial community structure and biodegradation function within these engineered ecosystems. To further explore this relationship, 16S rDNA tag pyrosequencing was applied to samples taken at four time points from a styrene-degrading biofilter undergoing variable operating conditions. Changes in microbial structure were observed between different stages of biofilter operation, and the level of styrene concentration was revealed to be a critical factor affecting these changes. Bacterial genera Azoarcus and Pseudomonas were among the dominant classified genera in the biofilter. Canonical correspondence analysis (CCA) and correlation analysis revealed that the genera Brevundimonas, Hydrogenophaga, and Achromobacter may play important roles in styrene degradation under increasing styrene concentrations. No significant correlations (P > 0.05) could be detected between biofilter operational/functional parameters and biodiversity measurements, although biological heterogeneity within biofilms and/or technical variability within pyrosequencing may have considerably affected these results. Percentages of selected bacterial taxonomic groups detected by fluorescence in situ hybridization (FISH) were compared to results from pyrosequencing in order to assess the effectiveness and limitations of each method for identifying each microbial taxon. Comparison of results revealed discrepancies between the two methods in the detected percentages of numerous taxonomic groups. Biases and technical limitations of both FISH and pyrosequencing, such as the binding of FISH probes to non-target microbial groups and lack of classification of sequences for defined taxonomic groups from pyrosequencing, may partially explain some differences between the two methods.

Unresolved fine-scale structure in solar coronal loop-tops

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

Scullion, E.; Van der Voort, L. Rouppe; Wedemeyer, S.

2014-12-10

New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer substructures within coronal loop cross-sections, in order to understand the nature of the solar corona. Here, we push this lower limit further to search for the finest coronal loop substructures, through taking advantage of the resolving power of the Swedish 1 m Solar Telescope/CRisp Imaging Spectro-Polarimeter (CRISP), together with co-observations from the Solar Dynamics Observatory/Atmospheric Image Assembly (AIA). High-resolution imaging of the chromospheric Hα 656.28 nm spectral line core and wings can, under certainmore » circumstances, allow one to deduce the topology of the local magnetic environment of the solar atmosphere where its observed. Here, we study post-flare coronal loops, which become filled with evaporated chromosphere that rapidly condenses into chromospheric clumps of plasma (detectable in Hα) known as a coronal rain, to investigate their fine-scale structure. We identify, through analysis of three data sets, large-scale catastrophic cooling in coronal loop-tops and the existence of multi-thermal, multi-stranded substructures. Many cool strands even extend fully intact from loop-top to footpoint. We discover that coronal loop fine-scale strands can appear bunched with as many as eight parallel strands within an AIA coronal loop cross-section. The strand number density versus cross-sectional width distribution, as detected by CRISP within AIA-defined coronal loops, most likely peaks at well below 100 km, and currently, 69% of the substructure strands are statistically unresolved in AIA coronal loops.« less

The HARPS search for southern extra-solar planets . XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone

NASA Astrophysics Data System (ADS)

Lo Curto, G.; Mayor, M.; Benz, W.; Bouchy, F.; Hébrard, G.; Lovis, C.; Moutou, C.; Naef, D.; Pepe, F.; Queloz, D.; Santos, N. C.; Segransan, D.; Udry, S.

2013-03-01

The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey of ≈850 nearby solar-type stars, and in the course of the past nine years we have monitored the radial velocity of HD 103774, HD 109271, and BD-061339. In this work we present the detection of five planets orbiting these stars, with msin (i) between 0.6 and 7 Neptune masses, four of which are in two multiple systems, comprising one super-Earth and one planet within the habitable zone of a late-type dwarf. Although for strategic reasons we chose efficiency over precision in this survey, we have the capability to detect planets down to the Neptune and super-Earth mass range as well as multiple systems, provided that enough data points are made available. Based on observations made with the HARPS instrument on the ESO 3.6 m telescope at La Silla (Chile), under the GTO program ID 072.C-0488 and the regular programs: 085.C-0019, 087.C-0831 and 089.C-0732. RV data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A59

Synthesis of zinc oxide nanoparticles on graphene-carbon nanotube hybrid for glucose biosensor applications.

PubMed

Hwa, Kuo-Yuan; Subramani, Boopathi

2014-12-15

Synthesis of zinc oxide nanoparticles incorporated graphene-carbon nanotubes hybrid (GR-CNT-ZnO) through a simple, one-pot method is demonstrated. The as-synthesized GR-CNT-ZnO composite is applied to fabricate an enzyme based glucose biosensor. The GOx immobilized on GR-CNT-ZnO composite exhibits well-defined redox peaks with a peak potential separation (ΔEp) of about 26 mV with enhanced peak currents, indicating a fast electron transfer at the modified electrode surface. The cyclic voltammetry measurements revealed that the modified film has high electrocatalytic ability towards glucose detection in the presence of oxygen. The proposed sensor has a wide linear detection range from 10 μM to 6.5 mM of glucose with a limit of detection (LOD) of 4.5 (±0.08) μM. In addition, the sensor possessed appreciable repeatability, reproducibility and remarkable stability for the sensitive determination of glucose. The practicality of this sensor has been demonstrated in human serum samples, with results being in good agreement with those determined using a standard photometric method. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of graphene-ionic liquid-chitosan composite-modified carbon molecular wire electrode for the sensitive determination of adenosine-5'-monophosphate.

PubMed

Shi, Fan; Gong, Shixing; Xu, Li; Zhu, Huanhuan; Sun, Zhenfan; Sun, Wei

2013-12-01

In this paper, a graphene (GR) ionic liquid (IL) 1-octyl-3-methylimidazolium hexafluorophosphate and chitosan composite-modified carbon molecular wire electrode (CMWE) was fabricated by a drop-casting method and further applied to the sensitive electrochemical detection of adenosine-5'-monophosphate (AMP). CMWE was prepared with diphenylacetylene (DPA) as the modifier and the binder. The properties of modified electrode were examined by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical behaviors of AMP was carefully investigated with enhanced responses appeared, which was due to the presence of GR-IL composite on the electrode surface with excellent electrocatalytic ability. A well-defined oxidation peak of AMP appeared at 1.314 V and the electrochemical parameters were calculated by electrochemical methods. Under the selected conditions, the oxidation peak current of AMP was proportional to its concentration in the range from 0.01 μM to 80.0 μM with the detection limit as 3.42 nM (3σ) by differential pulse voltammetry. The proposed method exhibited good selectivity and was applied to the detection of vidarabine monophosphate injection samples with satisfactory results. © 2013.

Development of a simple fluorescence-based microplate method for the high-throughput analysis of proline in wine samples.

PubMed

Robert-Peillard, Fabien; Boudenne, Jean-Luc; Coulomb, Bruno

2014-05-01

This paper presents a simple, accurate and multi-sample method for the determination of proline in wines thanks to a 96-well microplate technique. Proline is the most abundant amino acid in wine and is an important parameter related to wine characteristics or maturation processes of grape. In the current study, an improved application of the general method based on sodium hypochlorite oxidation and o-phthaldialdehyde (OPA)-thiol spectrofluorometric detection is described. The main interfering compounds for specific proline detection in wines are strongly reduced by selective reaction with OPA in a preliminary step under well-defined pH conditions. Application of the protocol after a 500-fold dilution of wine samples provides a working range between 0.02 and 2.90gL(-1), with a limit of detection of 7.50mgL(-1). Comparison and validation on real wine samples by ion-exchange chromatography prove that this procedure yields accurate results. Simplicity of the protocol used, with no need for centrifugation or filtration, organic solvents or high temperature enables its full implementation in plastic microplates and efficient application for routine analysis of proline in wines. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Comparative Analysis of Community Detection Algorithms on Artificial Networks

PubMed Central

Yang, Zhao; Algesheimer, René; Tessone, Claudio J.

2016-01-01

Many community detection algorithms have been developed to uncover the mesoscopic properties of complex networks. However how good an algorithm is, in terms of accuracy and computing time, remains still open. Testing algorithms on real-world network has certain restrictions which made their insights potentially biased: the networks are usually small, and the underlying communities are not defined objectively. In this study, we employ the Lancichinetti-Fortunato-Radicchi benchmark graph to test eight state-of-the-art algorithms. We quantify the accuracy using complementary measures and algorithms’ computing time. Based on simple network properties and the aforementioned results, we provide guidelines that help to choose the most adequate community detection algorithm for a given network. Moreover, these rules allow uncovering limitations in the use of specific algorithms given macroscopic network properties. Our contribution is threefold: firstly, we provide actual techniques to determine which is the most suited algorithm in most circumstances based on observable properties of the network under consideration. Secondly, we use the mixing parameter as an easily measurable indicator of finding the ranges of reliability of the different algorithms. Finally, we study the dependency with network size focusing on both the algorithm’s predicting power and the effective computing time. PMID:27476470

Modeling and Measurement Constraints in Fault Diagnostics for HVAC Systems

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

Najafi, Massieh; Auslander, David M.; Bartlett, Peter L.

2010-05-30

Many studies have shown that energy savings of five to fifteen percent are achievable in commercial buildings by detecting and correcting building faults, and optimizing building control systems. However, in spite of good progress in developing tools for determining HVAC diagnostics, methods to detect faults in HVAC systems are still generally undeveloped. Most approaches use numerical filtering or parameter estimation methods to compare data from energy meters and building sensors to predictions from mathematical or statistical models. They are effective when models are relatively accurate and data contain few errors. In this paper, we address the case where models aremore » imperfect and data are variable, uncertain, and can contain error. We apply a Bayesian updating approach that is systematic in managing and accounting for most forms of model and data errors. The proposed method uses both knowledge of first principle modeling and empirical results to analyze the system performance within the boundaries defined by practical constraints. We demonstrate the approach by detecting faults in commercial building air handling units. We find that the limitations that exist in air handling unit diagnostics due to practical constraints can generally be effectively addressed through the proposed approach.« less

Cross Matching of VIIRS Boat Detection and Vessel Monitoring System Tracks

NASA Astrophysics Data System (ADS)

Hsu, F. C.; Elvidge, C.; Zhizhin, M. N.; Baugh, K.; Ghosh, T.

2016-12-01

One approach to commercial fishing is to use use bright lights at night to attract catch. This is a widely used practice in East and Southeast Asia, but can also be found in other fisheries. In some cases, the deployed lighting exceeds 100,000 watts. Such lighting is distinctive in dark ocean and can even be seen from space with sensor such as Visible Infrared Imaging Radiometer Suite Day/Night Band (VIIRS-DNB). We have developed a VIIRS Boat Detection (VBD) system, which outputs lists of boat locations in near real time. One of the standard methods fishery agencies use to collect geospatial data on fishing boats is to require boats to carry Vessel Monitoring System beacons. We developed an algorithm to cross-match VBD data with VMS tracks. With this we are able to identify fishing boats that do not carry VMS beacons. In certain situations, this is an indicator of illegal fishing. The other application for this cross-matching is to define the VIIRS detection limits and developing a calibration to estimate deployed wattage. Here we demonstrate results of cross matching VBD and VMS for Indonesia as example to showcase its potential.

Percutaneous coronary angioscopy and stents

NASA Astrophysics Data System (ADS)

Heuser, Richard R.

1994-05-01

With the expanding array of therapies available for coronary intervention, the invasive cardiologist has many choices for treating a specific lesion in an individual patient. Certain types of lesions might respond more effectively with stents, particularly the rigid Palmax- Schatz device. Thrombus and dissection immediately following stent placement are associated with early occlusion, and the interventionist must be able to assess their presence pre- and post-stenting. Angiography is deficient in quantifying minimal disease and in defining lesion architecture and composition, as well as the plaque rupture and thrombosis associated with unstable angina. It is also imprecise in detecting dissection and thrombus. Intravascular ultrasound (IVUS) provides high-resolution images that delineate irregularities and other structures inside the lumen and within the vessel wall and surrounding tissues. Like angiography, IVUS has limited specificity for thrombus differentiation. Angioscopy is superior to angiography and IVUS in detecting thrombus and dissection. Angioscopy allows the clinician to assess the appearance of stent struts after deployment and at follow-up. This may aid in reducing acute complications as well as restenosis. Follow-up angioscopy of stents to detect thrombus or exposed struts may guide therapy in a patient who has clinical symptoms of restenosis.

Two-dimensional ytterbium oxide nanodisks based biosensor for selective detection of urea.

PubMed

Ibrahim, Ahmed A; Ahmad, Rafiq; Umar, Ahmad; Al-Assiri, M S; Al-Salami, A E; Kumar, Rajesh; Ansari, S G; Baskoutas, S

2017-12-15

Herein, we demonstrate synthesis and application of two-dimensional (2D) rectangular ytterbium oxide (Yb 2 O 3 ) nanodisks via a facile hydrothermal method. The structural, morphological, compositional, crystallinity, and phase properties of as-synthesized nanodisks were carried out using several analytical techniques that showed well defined 2D rectangular nanodisks/sheet like morphologies. The average thickness and edge length of the nanosheet structures were 20 ± 5nm and 600 ± 50nm, respectively. To develop urea biosensor, glassy carbon electrodes (GCE) were modified with Yb 2 O 3 nanodisks, followed by urease immobilization and Nafion membrane covering (GCE/Yb 2 O 3 /Urease/Nafion). The fabricated biosensor showed sensitivity of 124.84μAmM -1 cm -2 , wide linear range of 0.05-19mM, detection limit down to ~ 2μM, and fast response time of ~ 3s. The developed biosensor was also used for the urea detection in water samples through spike-recovery experiments, which illustrates satisfactory recoveries. In addition, the obtained desirable selectivity towards specific interfering species, long-term stability, reproducibility, and repeatability further confirm the potency of as-fabricated urea biosensor. Copyright © 2017 Elsevier B.V. All rights reserved.

Mapping quantitative trait loci for traits defined as ratios.

PubMed

Yang, Runqing; Li, Jiahan; Xu, Shizhong

2008-03-01

Many traits are defined as ratios of two quantitative traits. Methods of QTL mapping for regular quantitative traits are not optimal when applied to ratios due to lack of normality for traits defined as ratios. We develop a new method of QTL mapping for traits defined as ratios. The new method uses a special linear combination of the two component traits, and thus takes advantage of the normal property of the new variable. Simulation study shows that the new method can substantially increase the statistical power of QTL detection relative to the method which treats ratios as regular quantitative traits. The new method also outperforms the method that uses Box-Cox transformed ratio as the phenotype. A real example of QTL mapping for relative growth rate in soybean demonstrates that the new method can detect more QTL than existing methods of QTL mapping for traits defined as ratios.

A technique for setting analytical thresholds in massively parallel sequencing-based forensic DNA analysis

PubMed Central

2017-01-01

Amplicon (targeted) sequencing by massively parallel sequencing (PCR-MPS) is a potential method for use in forensic DNA analyses. In this application, PCR-MPS may supplement or replace other instrumental analysis methods such as capillary electrophoresis and Sanger sequencing for STR and mitochondrial DNA typing, respectively. PCR-MPS also may enable the expansion of forensic DNA analysis methods to include new marker systems such as single nucleotide polymorphisms (SNPs) and insertion/deletions (indels) that currently are assayable using various instrumental analysis methods including microarray and quantitative PCR. Acceptance of PCR-MPS as a forensic method will depend in part upon developing protocols and criteria that define the limitations of a method, including a defensible analytical threshold or method detection limit. This paper describes an approach to establish objective analytical thresholds suitable for multiplexed PCR-MPS methods. A definition is proposed for PCR-MPS method background noise, and an analytical threshold based on background noise is described. PMID:28542338

Consequences of Spin-Orbit Coupling at the Single Hole Level: Spin-Flip Tunneling and the Anisotropic g Factor

NASA Astrophysics Data System (ADS)

Bogan, A.; Studenikin, S. A.; Korkusinski, M.; Aers, G. C.; Gaudreau, L.; Zawadzki, P.; Sachrajda, A. S.; Tracy, L. A.; Reno, J. L.; Hargett, T. W.

2017-04-01

Hole transport experiments were performed on a gated double quantum dot device defined in a p -GaAs /AlGaAs heterostructure with a single hole occupancy in each dot. The charging diagram of the device was mapped out using charge detection confirming that the single hole limit is reached. In that limit, a detailed study of the two-hole spin system was performed using high bias magnetotransport spectroscopy. In contrast to electron systems, the hole spin was found not to be conserved during interdot resonant tunneling. This allows one to fully map out the two-hole energy spectrum as a function of the magnitude and the direction of the external magnetic field. The heavy-hole g factor was extracted and shown to be strongly anisotropic, with a value of 1.45 for a perpendicular field and close to zero for an in-plane field as required for hybridizing schemes between spin and photonic quantum platforms.

A technique for setting analytical thresholds in massively parallel sequencing-based forensic DNA analysis.

PubMed

Young, Brian; King, Jonathan L; Budowle, Bruce; Armogida, Luigi

2017-01-01

Amplicon (targeted) sequencing by massively parallel sequencing (PCR-MPS) is a potential method for use in forensic DNA analyses. In this application, PCR-MPS may supplement or replace other instrumental analysis methods such as capillary electrophoresis and Sanger sequencing for STR and mitochondrial DNA typing, respectively. PCR-MPS also may enable the expansion of forensic DNA analysis methods to include new marker systems such as single nucleotide polymorphisms (SNPs) and insertion/deletions (indels) that currently are assayable using various instrumental analysis methods including microarray and quantitative PCR. Acceptance of PCR-MPS as a forensic method will depend in part upon developing protocols and criteria that define the limitations of a method, including a defensible analytical threshold or method detection limit. This paper describes an approach to establish objective analytical thresholds suitable for multiplexed PCR-MPS methods. A definition is proposed for PCR-MPS method background noise, and an analytical threshold based on background noise is described.

Consequences of Spin-Orbit Coupling at the Single Hole Level: Spin-Flip Tunneling and the Anisotropic g Factor.

PubMed

Bogan, A; Studenikin, S A; Korkusinski, M; Aers, G C; Gaudreau, L; Zawadzki, P; Sachrajda, A S; Tracy, L A; Reno, J L; Hargett, T W

2017-04-21

Hole transport experiments were performed on a gated double quantum dot device defined in a p-GaAs/AlGaAs heterostructure with a single hole occupancy in each dot. The charging diagram of the device was mapped out using charge detection confirming that the single hole limit is reached. In that limit, a detailed study of the two-hole spin system was performed using high bias magnetotransport spectroscopy. In contrast to electron systems, the hole spin was found not to be conserved during interdot resonant tunneling. This allows one to fully map out the two-hole energy spectrum as a function of the magnitude and the direction of the external magnetic field. The heavy-hole g factor was extracted and shown to be strongly anisotropic, with a value of 1.45 for a perpendicular field and close to zero for an in-plane field as required for hybridizing schemes between spin and photonic quantum platforms.

The use of computational inspection to identify process window limiting hotspots and predict sub-15nm defects with high capture rate

NASA Astrophysics Data System (ADS)

Ham, Boo-Hyun; Kim, Il-Hwan; Park, Sung-Sik; Yeo, Sun-Young; Kim, Sang-Jin; Park, Dong-Woon; Park, Joon-Soo; Ryu, Chang-Hoon; Son, Bo-Kyeong; Hwang, Kyung-Bae; Shin, Jae-Min; Shin, Jangho; Park, Ki-Yeop; Park, Sean; Liu, Lei; Tien, Ming-Chun; Nachtwein, Angelique; Jochemsen, Marinus; Yan, Philip; Hu, Vincent; Jones, Christopher

2017-03-01

As critical dimensions for advanced two dimensional (2D) DUV patterning continue to shrink, the exact process window becomes increasingly difficult to determine. The defect size criteria shrink with the patterning critical dimensions and are well below the resolution of current optical inspection tools. As a result, it is more challenging for traditional bright field inspection tools to accurately discover the hotspots that define the process window. In this study, we use a novel computational inspection method to identify the depth-of-focus limiting features of a 10 nm node mask with 2D metal structures (single exposure) and compare the results to those obtained with a traditional process windows qualification (PWQ) method based on utilizing a focus modulated wafer and bright field inspection (BFI) to detect hotspot defects. The method is extended to litho-etch litho-etch (LELE) on a different test vehicle to show that overlay related bridging hotspots also can be identified.

Health care cost implications of sildenafil citrate.

PubMed

Miner, Martin

2004-09-01

As prescription drug expenditures increase, third-party payors are increasingly scrutinizing costs and reimbursement guidelines, such as for medications that treat chronic conditions that are not necessarily directly life threatening (i.e., obesity, nicotine addiction, and erectile dysfunction). To review the costs and consequences of pharmacy benefit reimbursement policies related to erectile dysfunction therapies, using sildenafil citrate as the case study. Data and references were found through searches of PubMed and Google. To meet the varied health needs of a defined population under reasonable resource constraints requires analysis of cost and of the economic and non-economic consequences of a treatment. Based on analysis of sildenafil data, oral therapy of erectile dysfunction provides substantial cost savings when compared with other treatment options and contributes insignificant overall costs to health plans. Regardless, health plans impose controls to limit reimbursement. Because erectile dysfunction is often a precursor to other conditions, such limitations could compromise detection and management of underlying disease (e.g., depressive, cardiovascular, and urogenital). Reimbursement restrictions may also decrease membership satisfaction and re-enrollment rates.

Consequences of spin-orbit coupling at the single hole level: Spin-flip tunneling and the anisotropic g factor

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

Bogan, A.; Studenikin, Sergei A.; Korkusinski, M.

Hole transport experiments were performed on a gated double quantum dot device defined in a p-GaAs/AlGaAs heterostructure with a single hole occupancy in each dot. The charging diagram of the device was mapped out using charge detection confirming that the single hole limit is reached. In that limit, a detailed study of the two-hole spin system was performed using high bias magnetotransport spectroscopy. In contrast to electron systems, the hole spin was found not to be conserved during interdot resonant tunneling. This allows one to fully map out the two-hole energy spectrum as a function of the magnitude and themore » direction of the external magnetic field. As a result, the heavy-hole g factor was extracted and shown to be strongly anisotropic, with a value of 1.45 for a perpendicular field and close to zero for an in-plane field as required for hybridizing schemes between spin and photonic quantum platforms.« less

S-Layer Protein-Based Biosensors.

PubMed

Schuster, Bernhard

2018-04-11

The present paper highlights the application of bacterial surface (S-) layer proteins as versatile components for the fabrication of biosensors. One technologically relevant feature of S-layer proteins is their ability to self-assemble on many surfaces and interfaces to form a crystalline two-dimensional (2D) protein lattice. The S-layer lattice on the surface of a biosensor becomes part of the interface architecture linking the bioreceptor to the transducer interface, which may cause signal amplification. The S-layer lattice as ultrathin, highly porous structure with functional groups in a well-defined special distribution and orientation and an overall anti-fouling characteristics can significantly raise the limit in terms of variety and the ease of bioreceptor immobilization, compactness of bioreceptor molecule arrangement, sensitivity, specificity, and detection limit for many types of biosensors. The present paper discusses and summarizes examples for the successful implementation of S-layer lattices on biosensor surfaces in order to give a comprehensive overview on the application potential of these bioinspired S-layer protein-based biosensors.

Gear Damage Detection Using Oil Debris Analysis

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.

2001-01-01

The purpose of this paper was to verify, when using an oil debris sensor, that accumulated mass predicts gear pitting damage and to identify a method to set threshold limits for damaged gears. Oil debris data was collected from 8 experiments with no damage and 8 with pitting damage in the NASA Glenn Spur Gear Fatigue Rig. Oil debris feature analysis was performed on this data. Video images of damage progression were also collected from 6 of the experiments with pitting damage. During each test, data from an oil debris sensor was monitored and recorded for the occurrence of pitting damage. The data measured from the oil debris sensor during experiments with damage and with no damage was used to identify membership functions to build a simple fuzzy logic model. Using fuzzy logic techniques and the oil debris data, threshold limits were defined that discriminate between stages of pitting wear. Results indicate accumulated mass combined with fuzzy logic analysis techniques is a good predictor of pitting damage on spur gears.

Consequences of spin-orbit coupling at the single hole level: Spin-flip tunneling and the anisotropic g factor

DOE PAGES

Bogan, A.; Studenikin, Sergei A.; Korkusinski, M.; ...

2017-04-20

Hole transport experiments were performed on a gated double quantum dot device defined in a p-GaAs/AlGaAs heterostructure with a single hole occupancy in each dot. The charging diagram of the device was mapped out using charge detection confirming that the single hole limit is reached. In that limit, a detailed study of the two-hole spin system was performed using high bias magnetotransport spectroscopy. In contrast to electron systems, the hole spin was found not to be conserved during interdot resonant tunneling. This allows one to fully map out the two-hole energy spectrum as a function of the magnitude and themore » direction of the external magnetic field. As a result, the heavy-hole g factor was extracted and shown to be strongly anisotropic, with a value of 1.45 for a perpendicular field and close to zero for an in-plane field as required for hybridizing schemes between spin and photonic quantum platforms.« less

The development of extraterrestrial civilizations and physical laws

NASA Astrophysics Data System (ADS)

Troitskii, V. S.

Consideration is given to the limiting characteristics of extraterrestrial civilizations as allowed by physical laws, and to the possible pathways and levels of development of such civilizations. The concept of an extraterrestrial civilization is defined in terms of the exchange of information, energy and matter both within a community of intelligent beings and between the community and its environment. The possible characteristics of such a civilization are then examined, including amount of populated space, population and population density, energy requirements and supply, information content, transportation capacity and lifetimes, and it is shown that the space occupiable by an extraterrestrial civilization is limited to the space around its star, due to the finite velocity of transport processes. The development of a type II civilization, making use of energy on the order of that put out by its star, is then examined, and constraints on energy production in such a civilization making impossible the establishment of an omnidirectional radio beacon detectable throughout the Galaxy are pointed out.

Microbial Ecosystems from the Deepest Regions of the Terrestrial Deep Biosphere

NASA Astrophysics Data System (ADS)

Moser, D. P.

2011-12-01

Although recent discoveries from four continents support the existence of microbial ecosystems across vast regions of our planet's inner space, very little is known about the abundance, distribution, diversity, or ultimate depth limit of subsurface microbial life. These deep lithospheric inhabitants must contend with a variety of potential challenges including high temperature, pressure and salinity, extreme isolation, and low energy flux. Interestingly, although deep microbial ecosystems are assumed to be energy and nutrient limited, it is often difficult to identify any one limiting substrate and the energy for deep life is often present in relative abundance (e.g. as geologically-produced hydrogen or other reduced gases). Recently, the concept of radiation-supported deep microbial ecosystems has gained traction in the literature. In particular, one bacterium, a Firmicute denoted Candidatus Desulforudis audaxviator, has been shown to be prominent, and in cases dominate, in deep fracture fluids from across the Witwatersrand basin of South Africa, where it appears to persist by utilizing H2 and SO42- derived from radiochemical reactions in U-rich host rock. Until recently, these mines were thought to define the geographic limit of this genus and species; however, our recent North American detection of D. audaxviator in radioactive subsurface water resulting from underground nuclear tests both supports earlier assertions concerning the radiochemical lifestyle of D. audaxviator and greatly expands its range. Results such as these suggest that novel modes of life operating without inputs from the photosphere are possible, and thus may have implications for the likelihood of detecting life off the Earth (e.g. in the Martian subsurface). In addition to underground nuclear detonation cavities, this talk will consider insights gained from ongoing microbial ecology assessments from several to date unexplored deep ecosystems accessed via deep mines in the Black Hills (USA) and Canadian Shield (Canada) and exploratory boreholes in the Southern Great Basin (USA). The tantalizing possibility that several of these new potential habitats have exceeded some limit for life will be also be explored.

Methods for combining payload parameter variations with input environment. [calculating design limit loads compatible with probabilistic structural design criteria

NASA Technical Reports Server (NTRS)

Merchant, D. H.

1976-01-01

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occurring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the method are also presented.

Extracellular Vesicle (EV) Array: microarray capturing of exosomes and other extracellular vesicles for multiplexed phenotyping.

PubMed

Jørgensen, Malene; Bæk, Rikke; Pedersen, Shona; Søndergaard, Evo K L; Kristensen, Søren R; Varming, Kim

2013-01-01

Exosomes are one of the several types of cell-derived vesicles with a diameter of 30-100 nm. These extracellular vesicles are recognized as potential markers of human diseases such as cancer. However, their use in diagnostic tests requires an objective and high-throughput method to define their phenotype and determine their concentration in biological fluids. To identify circulating as well as cell culture-derived vesicles, the current standard is immunoblotting or a flow cytometrical analysis for specific proteins, both of which requires large amounts of purified vesicles. Based on the technology of protein microarray, we hereby present a highly sensitive Extracellular Vesicle (EV) Array capable of detecting and phenotyping exosomes and other extracellular vesicles from unpurified starting material in a high-throughput manner. To only detect the exosomes captured on the EV Array, a cocktail of antibodies against the tetraspanins CD9, CD63 and CD81 was used. These antibodies were selected to ensure that all exosomes captured are detected, and concomitantly excluding the detection of other types of microvesicles. The limit of detection (LOD) was determined on exosomes derived from the colon cancer cell line LS180. It clarified that supernatant from only approximately 10(4) cells was needed to obtain signals or that only 2.5×10(4) exosomes were required for each microarray spot (~1 nL). Phenotyping was performed on plasma (1-10 µL) from 7 healthy donors, which were applied to the EV Array with a panel of antibodies against 21 different cellular surface antigens and cancer antigens. For each donor, there was considerable heterogeneity in the expression levels of individual markers. The protein profiles of the exosomes (defined as positive for CD9, CD63 and CD81) revealed that only the expression level of CD9 and CD81 was approximately equal in the 7 donors. This implies questioning the use of CD63 as a standard exosomal marker since the expression level of this tetraspanin was considerably lower.

Cloning of the koi herpesvirus (KHV) gene encoding thymidine kinase and its use for a highly sensitive PCR based diagnosis

PubMed Central

Bercovier, Herve; Fishman, Yolanta; Nahary, Ronen; Sinai, Sharon; Zlotkin, Amir; Eyngor, Marina; Gilad, Oren; Eldar, Avi; Hedrick, Ronald P

2005-01-01

Background Outbreaks with mass mortality among common carp Cyprinus carpio carpio and koi Cyprinus carpio koi have occurred worldwide since 1998. The herpes-like virus isolated from diseased fish is different from Herpesvirus cyprini and channel catfish virus and was accordingly designated koi herpesvirus (KHV). Diagnosis of KHV infection based on viral isolation and current PCR assays has a limited sensitivity and therefore new tools for the diagnosis of KHV infections are necessary. Results A robust and sensitive PCR assay based on a defined gene sequence of KHV was developed to improve the diagnosis of KHV infection. From a KHV genomic library, a hypothetical thymidine kinase gene (TK) was identified, subcloned and expressed as a recombinant protein. Preliminary characterization of the recombinant TK showed that it has a kinase activity using dTTP but not dCTP as a substrate. A PCR assay based on primers selected from the defined DNA sequence of the TK gene was developed and resulted in a 409 bp amplified fragment. The TK based PCR assay did not amplify the DNAs of other fish herpesviruses such as Herpesvirus cyprini (CHV) and the channel catfish virus (CCV). The TK based PCR assay was specific for the detection of KHV and was able to detect as little as 10 fentograms of KHV DNA corresponding to 30 virions. The TK based PCR was compared to previously described PCR assays and to viral culture in diseased fish and was shown to be the most sensitive method of diagnosis of KHV infection. Conclusion The TK based PCR assay developed in this work was shown to be specific for the detection of KHV. The TK based PCR assay was more sensitive for the detection of KHV than previously described PCR assays; it was as sensitive as virus isolation which is the golden standard method for KHV diagnosis and was able to detect as little as 10 fentograms of KHV DNA corresponding to 30 virions. PMID:15774009

Longitudinal profiles of highly sensitive hepatitis B surface antigen levels: re-evaluation of HBsAg seroclearance.

PubMed

Seto, Wai-Kay; Tanaka, Yasuhito; Wong, Danny K-H; Shinkai, Noboru; Cheung, Ka-Shing; Liu, Kevin S-H; Fung, James; Lai, Ching-Lung; Yuen, Man-Fung

2016-05-01

Serologic profiles after hepatitis B surface antigen (HBsAg) seroclearance in chronic hepatitis B (CHB) have not been well-studied. We employed a highly sensitive HBsAg (hs-HBsAg) assay (lower detection limit 0.5 mIU/ml), 100 times more sensitive than conventional HBsAg measurements. CHB patients achieving HBsAg seroclearance defined by conventional assays were followed up for serum hs-HBsAg, HBV DNA and antibody to HBsAg (anti-HBs) levels at 0 months, 6-12 months and 3-5 years after HBsAg seroclearance. Factors associated with hs-HBsAg detectability were determined. One hundred and nine patients were recruited; 94 (86.2%) were followed up to years 3-5; and 25 patients (22.9%) were on nucleoside analogue therapy for a median duration of 6.0 (range 1.5-12.7) years before HBsAg seroclearance. Detectable hs-HBsAg was noted in 88 (80.7%), 60 (55.0%) and 20 (21.3%) patients at 0 months, 6-12 months and 3-5 years respectively. At years 3-5, genotype B patients, when compared to genotype C patients, had a higher anti-HBs positive rate (63.2% and 41.1% respectively, P = 0.036). Serum anti-HBs positivity, when compared to persistent anti-HBs negativity, was associated with a lower rate of hs-HBsAg detection (7.4% and 40% respectively, P < 0.001). Multivariate analysis showed anti-HBs negativity at years 3-5 to be independently associated with persistently positive hs-HBsAg (P = 0.007, odds ratio 7.1, 95% confidence interval 1.7-29.3). Serum hs-HBsAg could detect HBsAg presence in a substantial proportion of CHB after HBsAg seroclearance defined by conventional assays, especially among anti-HBs negative individuals. Serum hs-HBsAg could potentially assist differentiating HBsAg-negative CHB from individuals with only past HBV exposure without carrier state. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be emitting pollutants in excess of the federal emission standards or family emission limits, as defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were... communication sent to locomotive or locomotive engine owners or dealers shall contain any statement or...

Spectral characterization as a tool for parchment analysis

NASA Astrophysics Data System (ADS)

Radis, Michela; Iacomussi, Paola; Rossi, Giuseppe

2015-06-01

The paper presents an investigation on the correlation between spectral characteristics and conservation conditions of parchment to define a NON invasive methodology able to detect and monitor deterioration process in historical parchment without the need of taking small samples. To verify the feasibility and define the most appropriate measurement method, several samples of contemporary parchments, produced following ancient recipes and coming from different animal species, with different degrees of artificially induced damage, were analyzed. The SRF and STF of each sample were measured in the same point, before and after each step of the artificial ageing treatment. Having at disposal a parchment coming from a whole lamb leather, allowed also the study of the correlations between the variations of SRF - STF and the intrinsic factors of a parchment like the variability of animal skin anatomy and of manufacturing. Analyzing different samples allowed also the definition of the measuring method sensitivity and of reference spectrum for the different animal species parchments with accuracy limits. The definition of a reference spectrum of not damaged parchment with acceptability limits is a necessary step for understanding, through SRF - STF measurements, historical parchments conservation conditions: indeed it is necessary to know if deviations from the reference spectrum are ascribable to damage or only to parchment anatomic/production variability. As a case study, the method has been applied to two historical parchment scrolls stored at the Archivio di Stato di Torino (Italy). The SRF - STF of both scrolls was acquired in several points of the scroll, the average spectrum of each scroll was compared with the reference spectra with the relative tolerance limits, recognizing the animal species and damage alterations and demonstrating the feasibility of the method.

Three-Dimensional Distribution of Larval Fish Habitats in the Shallow Oxygen Minimum Zone in the Eastern Tropical Pacific Ocean off Mexico

NASA Astrophysics Data System (ADS)

Davies, S.; Sanchez Velasco, L.; Beier, E.; Godinez, V. M.; Barton, E. D.; Tamayo, A.

2016-02-01

Three-dimensional distribution of larval fish habitats was analyzed, from the upper limit of the shallow oxygen minimum zone ( 0.2 mL/L) to the sea surface, in the eastern tropical Pacific Ocean off Mexico in February 2010.The upper limit rises from 250 m depth in the entrance of the Gulf of California to 80 m depth off Cabo Corrientes. Three larval fish habitats were defined statistically: (i) a Gulf of California habitat dominated by Anchoa spp. larvae (epipelagic species), constrained to the oxygenated surface layer (>3.5 mL/L) in and above the thermocline ( 60 m depth), and separated by a salinity front from the Tropical Pacific habitat; (ii) a Tropical Pacific habitat, dominated by Vinciguerria lucetia larvae (mesopelagic species), located throughout the sampled water column, but with the highest abundance in the oxygenated upper layer above the thermocline; (iii) an Oxygen Minimum habitat defined mostly below the thermocline in hypoxic (<1 mL/L; 70 m depth) and anoxic (<0.2 mL/L; 80 m depth) water off Cabo Corrientes. This subsurface hypoxic habitat had the highest species richness and larval abundance, with dominance of Bregmaceros bathymaster, an endemic neritic pelagic species; which was an unexpected result. This maybe associated with the shoaling of the upper limit of the shallow oxygen minimum zone near the coast, a result of the strong costal upwelling detected by the Bakun Index. In this region of strong and semi-continuous coastal upwelling in the eastern tropical Pacific off Mexico, the shallow hypoxic water does not have dramatic effects on the total larval fish abundance but appears to affect species composition.

40 CFR Table 1 to Subpart Yyyy of... - Emission Limitations

Code of Federal Regulations, 2011 CFR

2011-07-01

... turbine as defined in this subpart, 3. a diffusion flame gas-fired stationary combustion turbine as defined in this subpart, or 4. a diffusion flame oil-fired stationary combustion turbine as defined in...

40 CFR Table 1 to Subpart Yyyy of... - Emission Limitations

Code of Federal Regulations, 2010 CFR

2010-07-01

... turbine as defined in this subpart, 3. a diffusion flame gas-fired stationary combustion turbine as defined in this subpart, or 4. a diffusion flame oil-fired stationary combustion turbine as defined in...

Search times and probability of detection in time-limited search

NASA Astrophysics Data System (ADS)

Wilson, David; Devitt, Nicole; Maurer, Tana

2005-05-01

When modeling the search and target acquisition process, probability of detection as a function of time is important to war games and physical entity simulations. Recent US Army RDECOM CERDEC Night Vision and Electronics Sensor Directorate modeling of search and detection has focused on time-limited search. Developing the relationship between detection probability and time of search as a differential equation is explored. One of the parameters in the current formula for probability of detection in time-limited search corresponds to the mean time to detect in time-unlimited search. However, the mean time to detect in time-limited search is shorter than the mean time to detect in time-unlimited search and the relationship between them is a mathematical relationship between these two mean times. This simple relationship is derived.

The interaction between breathing and swallowing in amyotrophic lateral sclerosis.

PubMed

Erdem, Nazan Simsek; Karaali, Kamil; Ünal, Ali; Kızılay, Ferah; Öğüş, Candan; Uysal, Hilmi

2016-12-01

The aim of the study is to determine the association between respiratory swallow patterns in amyotrophic lateral sclerosis (ALS) patients. Furthermore, it aims to clarify the role of the dysphagia limit in defining the relationship between swallowing disorders and respiratory disorders. Functional rating scales were used to describe swallowing and respiratory function. Swallowing was observed using the dysphagia limit. Dysphagia limit is the volume at which a second or more swallows are required to swallow the whole bolus. Laryngeal and chest movement sensors, pulmonary function tests, submental, and diaphragm electromyography activity were used to evaluate the relationship between swallowing and respiratory phase. Of the 27 patients included in the study, 14 were dysphagic and 13 were non-dysphagic. Tests showed normal respiratory function in 11 of the non-dysphagic patients and 3 of the dysphagic patients. There was a high correlation between the dysphagia limit and Amyotrophic Lateral Sclerosis Functional Rating Scale swallowing parameters. Non-dysphagic patients were able to swallow during inspiration but only six patients in the dysphagic group were able to swallow during inspiration. The occurrence of dysphagia in ALS is related to piecemeal deglutition and respiration consistency during swallowing. Detecting the timing of disturbances in the relationship between swallowing and respiration may be a way of identifying dysphagia. Dysphagia limit may be a useful, complementary test for assessing swallowing disturbances in amyotrophic lateral sclerosis.

GOODS-Herschel: identification of the individual galaxies responsible for the 80-290 μm cosmic infrared background

NASA Astrophysics Data System (ADS)

Leiton, R.; Elbaz, D.; Okumura, K.; Hwang, H. S.; Magdis, G.; Magnelli, B.; Valtchanov, I.; Dickinson, M.; Béthermin, M.; Schreiber, C.; Charmandaris, V.; Dole, H.; Juneau, S.; Le Borgne, D.; Pannella, M.; Pope, A.; Popesso, P.

2015-07-01

Aims: We propose a new method of pushing Herschel to its faintest detection limits using universal trends in the redshift evolution of the far infrared over 24 μm colours in the well-sampled GOODS-North field. An extension to other fields with less multi-wavelength information is presented. This method is applied here to raise the contribution of individually detected Herschel sources to the cosmic infrared background (CIRB) by a factor 5 close to its peak at 250 μm and more than 3 in the 350 and 500 μm bands. Methods: We produce realistic mock Herschel images of the deep PACS and SPIRE images of the GOODS-North field from the GOODS-Herschel key program and use them to quantify the confusion noise at the position of individual sources, i.e., estimate a "local confusion noise". Two methods are used to identify sources with reliable photometric accuracy extracted using 24 μm prior positions. The clean index (CI), previously defined but validated here with simulations, which measures the presence of bright 24 μm neighbours and the photometric accuracy index (PAI) directly extracted from the mock Herschel images. Results: Both methods converge to comparable depths and fractions of the CIRB resolved into sources individually detected with Herschel. After correction for completeness, thanks to our mock Herschel images, individually detected sources make up as much as 54% and 60% of the CIRB in the PACS bands down to 1.1 mJy at 100 μm and 2.2 mJy at 160 μm and 55, 33, and 13% of the CIRB in the SPIRE bands down to 2.5, 5, and 9 mJy at 250 μm, 350 μm, and 500 μm, respectively. The latter depths improve the detection limits of Herschel by factors of 5 at 250 μm, and 3 at 350 μm and 500 μm as compared to the standard confusion limit. Interestingly, the dominant contributors to the CIRB in all Herschel bands appear to be distant siblings of the Milky Way (z ~ 0.96 for λ< 300 μm) with a stellar mass of M⋆ ~ 9 × 1010M⊙.

Day-On, Day-Off emtricitabine, tenofovir disoproxil fumarate and efavirenz single tablet regimen (DODO) as maintenance therapy in HIV-infected patients.

PubMed

Costantini, Andrea; Tontini, Chiara; Rocchi, Monia; Martini, Matteo; Butini, Luca

2018-06-01

Reduced dose schedules may be feasible options to simplify antiretroviral therapy (ART) in selected HIV-1-infected individuals. Efficacy and safety of a Day-on, Day-off (DODO) schedule of tenofovir disoproxil fumarate, emtricitabine and efavirenz (FTC/TDF/EFV) single tablet regimen (STR) was assessed. Twenty-seven patients were prescribed the DODO schedule and were monitored for 48 weeks. Switching criteria were: no previous ART failure, no AIDS-defining illnesses, T CD4 cell nadir >200/mmc, and HIV-RNA below detection limit (40 copies/mL) for at least six months. Clinical and laboratory data, including plasma HIV-RNA levels, T CD4 and CD8 counts, liver and kidney function, lipid levels and ultrasensitive C-reactive protein (us-CRP) were assessed at baseline, week 4, 12, 24, and 48. Statistical analysis was performed by paired Student's T-test for comparison between baseline and each time point and Chi square test for CD4/CD8 ratio comparison. In all, 26 out of 27 patients maintained plasma HIV-RNA levels below the detection limit through the entire follow-up. One patient experienced low level plasma HIV-RNA rebound at week 36 (47 copies/ml) and immediately reverted to the conventional dose schedule of FTC/TDF/EFV; plasma HIV-RNA was undetectable after four weeks. No major changes on liver and kidney function tests, lipid levels and us-CRP were observed. Although no profound modifications of T CD4 count were observed during follow-up, the CD4/CD8 ratio increased significantly at week 48 compared to the baseline (p<0.05). In conclusion, 48-week DODO administration of the fixed dose FTC/TDF/EFV STR combination was safe and effective in maintaining HIV viral replication below the detection limit in a selected group of HIV-1-infected individuals.

Direct electrochemistry with enhanced electrocatalytic activity of hemoglobin in hybrid modified electrodes composed of graphene and multi-walled carbon nanotubes.

PubMed

Sun, Wei; Cao, Lili; Deng, Ying; Gong, Shixing; Shi, Fan; Li, Gaonan; Sun, Zhenfan

2013-06-05

A graphene (GR) and multi-walled carbon nanotubes (MWCNT) hybrid was prepared and modified on a 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on GR-MWCNT/CILE surface with Nafion as the film forming material and the modified electrode was denoted as Nafion/Hb-GR-MWCNT/CILE. Spectroscopic results revealed that Hb molecules retained its native structure in the GR-MWCNT hybird. Electrochemical behaviors of Hb were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks obtained, which indicated that direct electron transfer of Hb was realized in the hybrid modified electrode. The result could be attributed to the synergistic effects of GR-MWCNT hybrid with enlarged surface area and improved conductivity through the formation of a three-dimensional network. Electrochemical parameters of the immobilized Hb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.03, the charge transfer coefficient (a) as 0.58 and the electron-transfer rate constant (ks) as 0.97 s(-1). The Hb modified electrode showed good electrocatalytic ability toward the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.05 to 38.0 mmol L(-1) with a detection limit of 0.0153 mmol L(-1) (3σ), H2O2 in the concentration range from 0.1 to 516.0 mmol L(-1) with a detection limit of 34.9 nmol/L (3σ) and NaNO2 in the concentration range from 0.5 to 650.0 mmol L(-1) with a detection limit of 0.282 μmol L(-1) (3σ). So the proposed electrode had the potential application in the third-generation electrochemical biosensors without mediator. Copyright © 2013 Elsevier B.V. All rights reserved.

Multidrug and extensively drug-resistant tuberculosis.

PubMed

Maitre, T; Aubry, A; Jarlier, V; Robert, J; Veziris, N

2017-02-01

The emergence of drug-resistant tuberculosis (TB) compromises global tuberculosis control. The incidence of multidrug-resistant strains (MDR) defined as resistant to the two main antituberculosis drugs, rifampicin and isoniazid, was raised in the 1990s. Ten percent of these strains have developed additional resistance to the main second-line antituberculosis drugs: fluoroquinolones and aminoglycosides. These strains are defined as extensively drug-resistant (XDR). The prognosis of MDR-TB and XDR-TB is poor due to limited therapeutic resources. However, many new innovations may lead to a radical change in this field. Genotypic testing is now able to detect drug resistance within a few hours. Genotypic diagnosis of rifampicin resistance is now recommended in France for each new case of TB. The currently recommended treatment for MDR-TB is long (18-24 months) and toxic. It is, however, on the verge of being replaced by a 9-month treatment. New antituberculosis drugs such as bedaquiline and delamanid should also improve the prognosis of MDR-TB and XDR-TB. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Convergent? Minds? Some questions about mental evolution.

PubMed

Cartmill, Matt

2017-06-06

In investigating convergent minds, we need to be sure that the things we are looking at are both minds and convergent. In determining whether a shared character state represents a convergence between two organisms, we must know the wider distribution and primitive state of that character so that we can map that character and its state transitions onto a phylogenetic tree. When we do this, some apparently primitive shared traits may prove to represent convergent losses of cognitive capacities. To avoid having to talk about the minds of plants and paramecia, we need to go beyond assessments of behaviourally defined cognition to ask questions about mind in the primary sense of the word, defined by the presence of mental events and consciousness. These phenomena depend upon the possession of brains of adequate size and centralized ontogeny and organization. They are probably limited to vertebrates. Recent discoveries suggest that consciousness is adaptively valuable as a late error-detection mechanism in the initiation of action, and point to experimental techniques for assessing its presence or absence in non-human mammals.

Computerized EEG analysis for studying the effect of drugs on the central nervous system.

PubMed

Rosadini, G; Cavazza, B; Rodriguez, G; Sannita, W G; Siccardi, A

1977-11-01

Samples of our experience in quantitative pharmaco-EEG are reviewed to discuss and define its applicability and limits. Simple processing systems, such as the computation of Hjorth's descriptors, are useful for on-line monitoring of drug-induced EEG modifications which are evident also at the visual visual analysis. Power spectral analysis is suitable to identify and quantify EEG effects not evident at the visual inspection. It demonstrated how the EEG effects of compounds in a long-acting formulation vary according to the sampling time and the explored cerebral area. EEG modifications not detected by power spectral analysis can be defined by comparing statistically (F test) the spectral values of the EEG from a single lead at the different samples (longitudinal comparison), or the spectral values from different leads at any sample (intrahemispheric comparison). The presently available procedures of quantitative pharmaco-EEG are effective when applied to the study of mutltilead EEG recordings in a statistically significant sample of population. They do not seem reliable in the monitoring of directing of neuropyschiatric therapies in single patients, due to individual variability of drug effects.

Chronic Iron Limitation Confers Transient Resistance to Oxidative Stress in Marine Diatoms.

PubMed

Graff van Creveld, Shiri; Rosenwasser, Shilo; Levin, Yishai; Vardi, Assaf

2016-10-01

Diatoms are single-celled, photosynthetic, bloom-forming algae that are responsible for at least 20% of global primary production. Nevertheless, more than 30% of the oceans are considered "ocean deserts" due to iron limitation. We used the diatom Phaeodactylum tricornutum as a model system to explore diatom's response to iron limitation and its interplay with susceptibility to oxidative stress. By analyzing physiological parameters and proteome profiling, we defined two distinct phases: short-term (<3 d, phase I) and chronic (>5 d, phase II) iron limitation. While at phase I no significant changes in physiological parameters were observed, molecular markers for iron starvation, such as Iron Starvation Induced Protein and flavodoxin, were highly up-regulated. At phase II, down-regulation of numerous iron-containing proteins was detected in parallel to reduction in growth rate, chlorophyll content, photosynthetic activity, respiration rate, and antioxidant capacity. Intriguingly, while application of oxidative stress to phase I and II iron-limited cells similarly oxidized the reduced glutathione (GSH) pool, phase II iron limitation exhibited transient resistance to oxidative stress, despite the down regulation of many antioxidant proteins. By comparing proteomic profiles of P. tricornutum under iron limitation and metatranscriptomic data of an iron enrichment experiment conducted in the Pacific Ocean, we propose that iron-limited cells in the natural environment resemble the phase II metabolic state. These results provide insights into the trade-off between optimal growth rate and susceptibility to oxidative stress in the response of diatoms to iron quota in the marine environment. © 2016 American Society of Plant Biologists. All Rights Reserved.

Chronic Iron Limitation Confers Transient Resistance to Oxidative Stress in Marine Diatoms1

PubMed Central

Graff van Creveld, Shiri; Rosenwasser, Shilo; Vardi, Assaf

2016-01-01

Diatoms are single-celled, photosynthetic, bloom-forming algae that are responsible for at least 20% of global primary production. Nevertheless, more than 30% of the oceans are considered “ocean deserts” due to iron limitation. We used the diatom Phaeodactylum tricornutum as a model system to explore diatom’s response to iron limitation and its interplay with susceptibility to oxidative stress. By analyzing physiological parameters and proteome profiling, we defined two distinct phases: short-term (<3 d, phase I) and chronic (>5 d, phase II) iron limitation. While at phase I no significant changes in physiological parameters were observed, molecular markers for iron starvation, such as Iron Starvation Induced Protein and flavodoxin, were highly up-regulated. At phase II, down-regulation of numerous iron-containing proteins was detected in parallel to reduction in growth rate, chlorophyll content, photosynthetic activity, respiration rate, and antioxidant capacity. Intriguingly, while application of oxidative stress to phase I and II iron-limited cells similarly oxidized the reduced glutathione (GSH) pool, phase II iron limitation exhibited transient resistance to oxidative stress, despite the down regulation of many antioxidant proteins. By comparing proteomic profiles of P. tricornutum under iron limitation and metatranscriptomic data of an iron enrichment experiment conducted in the Pacific Ocean, we propose that iron-limited cells in the natural environment resemble the phase II metabolic state. These results provide insights into the trade-off between optimal growth rate and susceptibility to oxidative stress in the response of diatoms to iron quota in the marine environment. PMID:27503604

Shot noise limited detection of OH using the technique of laser induced fluorescence

NASA Technical Reports Server (NTRS)

Bakalyar, D. M.; Davis, L. I., Jr.; Guo, C.; James, J. V.; Kakos, S.; Morris, P. T.; Wang, C. C.

1984-01-01

Nearly shot-noise limited detection of OH using the technique of laser-induced fluorescence is reported. A LIDAR configuration is used to excite fluorescence in a large volume and a narrow-bandwidth interference filter provides spectral discrimination. This arrangement alleviates the effect of ozone interference and facilitates image processing at relatively close distances. The detection limit is determined mainly by the shot-noise of the solar background. Ground-based measurements in Dearborn indicate a detection limit of better than 1 x 10 to the 6th power OH/cubic cm over a forty-minute acquisition period. Under favorable conditions, a comparable detection limit was also observed for airborne measurements.

Shot noise limited detection of OH using the technique of laser-induced fluorescence

NASA Technical Reports Server (NTRS)

Bakalyar, D. M.; Davis, L. I., Jr.; Guo, C.; James, J. V.; Wang, C. C.; Kakos, S.; Morris, P. T.

1984-01-01

Nearly shot-noise limited detection of OH using the technique of laser-induced fluorescence is reported. A LIDAR configuration is used to excite fluoresence in a large volume and a narrow-bandwidth interference filter provides spectral discrimination. This arrangement alleviates the effect of ozone interference and facilitates image processing at relatively close distances. The detection limit is determined mainly by the short-noise of the solar background. Ground-based measurements in Dearborn indicate a detection limit of better than 1 x 10 to the 6th power OH/cubic cm over a forty-minute acquisition period. Under favorable conditions, a comparable detection limit was also observed for airborne measurements.

Detecting natural occlusion boundaries using local cues

PubMed Central

DiMattina, Christopher; Fox, Sean A.; Lewicki, Michael S.

2012-01-01

Occlusion boundaries and junctions provide important cues for inferring three-dimensional scene organization from two-dimensional images. Although several investigators in machine vision have developed algorithms for detecting occlusions and other edges in natural images, relatively few psychophysics or neurophysiology studies have investigated what features are used by the visual system to detect natural occlusions. In this study, we addressed this question using a psychophysical experiment where subjects discriminated image patches containing occlusions from patches containing surfaces. Image patches were drawn from a novel occlusion database containing labeled occlusion boundaries and textured surfaces in a variety of natural scenes. Consistent with related previous work, we found that relatively large image patches were needed to attain reliable performance, suggesting that human subjects integrate complex information over a large spatial region to detect natural occlusions. By defining machine observers using a set of previously studied features measured from natural occlusions and surfaces, we demonstrate that simple features defined at the spatial scale of the image patch are insufficient to account for human performance in the task. To define machine observers using a more biologically plausible multiscale feature set, we trained standard linear and neural network classifiers on the rectified outputs of a Gabor filter bank applied to the image patches. We found that simple linear classifiers could not match human performance, while a neural network classifier combining filter information across location and spatial scale compared well. These results demonstrate the importance of combining a variety of cues defined at multiple spatial scales for detecting natural occlusions. PMID:23255731

Evaluation of volatile organic compound (VOC) blank data and application of study reporting levels to groundwater data collected for the California GAMA Priority Basin Project, May 2004 through September 2010

USGS Publications Warehouse

Fram, Miranda S.; Olsen, Lisa D.; Belitz, Kenneth

2012-01-01

Volatile organic compounds (VOCs) were analyzed in quality-control samples collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. From May 2004 through September 2010, a total of 2,026 groundwater samples, 211 field blanks, and 109 source-solution blanks were collected and analyzed for concentrations of 85 VOCs. Results from analyses of these field and source-solution blanks and of 2,411 laboratory instrument blanks during the same time period were used to assess the quality of data for the 2,026 groundwater samples. Eighteen VOCs were detected in field blanks or source-solution blanks: acetone, benzene, bromodichloromethane, 2-butanone, carbon disulfide, chloroform, 1,1-dichloroethene, dichloromethane, ethylbenzene, tetrachloroethene, styrene, tetrahydrofuran, toluene, trichloroethene, trichlorofluoromethane, 1,2,4-trimethylbenzene, m- and p-xylenes, and o-xylene. The objective of the evaluation of the VOC-blank data was to determine if study reporting levels (SRLs) were needed for any of the VOCs detected in blanks to ensure the quality of the data from groundwater samples. An SRL is equivalent to a raised reporting level that is used in place of the reporting level used by the analyzing laboratory [long‑term method detection level (LT-MDL) or laboratory reporting level (LRL)] to reduce the probability of reporting false-positive detections. Evaluation of VOC-blank data was done in three stages: (1) identification of a set of representative quality‑control field blanks (QCFBs) to be used for calculation of SRLs and identification of VOCs amenable to the SRL approach, (2) evaluation of potential sources of contamination to blanks and groundwater samples by VOCs detected in field blanks, and (3) selection of appropriate SRLs from among four potential SRLs for VOCs detected in field blanks and application of those SRLs to the groundwater data. An important conclusion from this study is that to ensure the quality of the data from groundwater samples, it was necessary to apply different methods of determining SRLs from field blank data to different VOCs, rather than use the same method for all VOCs. Four potential SRL values were defined by using three approaches: two values were defined by using a binomial probability method based on one-sided, nonparametric upper confidence limits, one was defined as equal to the maximum concentration detected in the field blanks, and one was defined as equal to the maximum laboratory method detection level used during the period when samples were collected for the project. The differences in detection frequencies and concentrations among different types of blanks (laboratory instrument blanks, source-solution blanks, and field blanks collected with three different sampling equipment configurations) and groundwater samples were used to infer the sources and mechanisms of contamination for each VOC detection in field blanks. Other chemical data for the groundwater samples (oxidation-reduction state, co-occurrence of VOCs, groundwater age) and ancillary information about the well sites (land use, presence of known sources of contamination) were used to evaluate whether the patterns of detections of VOCs in groundwater samples before and after application of potential SRLs were plausible. On this basis, the appropriate SRL was selected for each VOC that was determined to require an SRL. The SRLs for ethylbenzene [0.06 microgram per liter (μg/L)], m- and p-xylenes (0.33 μg/L), o-xylene (0.12 μg/L), toluene (0.69 μg/L), and 1,2,4-trimethylbenzene (0.56 μg/L) corresponded to the highest concentrations detected in the QCFBs and were selected because they resulted in the most censoring of groundwater data. Comparisons of hydrocarbon ratios in groundwater samples and blanks and comparisons between detection frequencies of the five hydrocarbons in groundwater samples and different types of blanks suggested three dominant sources of contamination that affected groundwater samples and blanks: (1) ethylbenzene, m- and p-xylenes, o-xylene, and toluene from fuel or exhaust components sorbed onto sampling lines, (2) toluene from vials and the source blank water, and (3) 1,2,4-trimethylbenzene from materials used for collection of samples for radon-222 analysis.

The Savannah River Site`s Groundwater Monitoring Program. Second quarter, 1991

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

Not Available

1992-01-10

The Environmental Protection Department/Environmental Monitoring Section (EPD/EMS) administers the Savannah River Site`s (SRS) Groundwater Monitoring Program. During second quarter 1991 EPD/EMS conducted extensive sampling of monitoring wells. EPD/EMS established two sets of flagging criteria in 1986 to assist in the management of sample results. The flagging criteria do not define contamination levels; instead, they aid personnel in sample scheduling, interpretation of data, and trend identification. Beginning in 1991, the flagging criteria are based on EPA drinking water standards and method detection limits. A detailed explanation of the current flagging criteria is presented in the Flagging Criteria section of this document.more » Analytical results from second quarter 1991 are listed in this report.« less

The Savannah River Site's Groundwater Monitoring Program

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

Not Available

1992-01-10

The Environmental Protection Department/Environmental Monitoring Section (EPD/EMS) administers the Savannah River Site's (SRS) Groundwater Monitoring Program. During second quarter 1991 EPD/EMS conducted extensive sampling of monitoring wells. EPD/EMS established two sets of flagging criteria in 1986 to assist in the management of sample results. The flagging criteria do not define contamination levels; instead, they aid personnel in sample scheduling, interpretation of data, and trend identification. Beginning in 1991, the flagging criteria are based on EPA drinking water standards and method detection limits. A detailed explanation of the current flagging criteria is presented in the Flagging Criteria section of this document.more » Analytical results from second quarter 1991 are listed in this report.« less

Measurement of neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photon induced reaction on natC using laser electron photon beam at NewSUBARU

NASA Astrophysics Data System (ADS)

Itoga, Toshiro; Nakashima, Hiroshi; Sanami, Toshiya; Namito, Yoshihito; Kirihara, Yoichi; Miyamoto, Shuji; Takemoto, Akinori; Yamaguchi, Masashi; Asano, Yoshihiro

2017-09-01

Photo-neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photons on natC were measured using laser Compton scattering facility at NewSUBARU BL01. The photon energy spectra were evaluated through measurements and simulations with collimator sizes and arrangements for the laser electron photon. The neutron energy spectra for the natC(g,xn) reaction were measured at 60 degrees in horizontal and 90 degrees in horizontal and vertical with respect to incident photon. The spectra show almost isotropic angular distribution and flat energy distribution from detection threshold to upper limit defined by reaction Q-value.

Development of a Novel Two Dimensional Surface Plasmon Resonance Sensor Using Multiplied Beam Splitting Optics

PubMed Central

Hemmi, Akihide; Mizumura, Ryosuke; Kawanishi, Ryuta; Nakajima, Hizuru; Zeng, Hulie; Uchiyama, Katsumi; Kaneki, Noriaki; Imato, Toshihiko

2013-01-01

A novel two dimensional surface plasmon resonance (SPR) sensor system with a multi-point sensing region is described. The use of multiplied beam splitting optics, as a core technology, permitted multi-point sensing to be achieved. This system was capable of simultaneously measuring nine sensing points. Calibration curves for sucrose obtained on nine sensing points were linear in the range of 0–10% with a correlation factor of 0.996–0.998 with a relative standard deviation of 0.090–4.0%. The detection limits defined as S/N = 3 were 1.98 × 10−6–3.91 × 10−5 RIU. This sensitivity is comparable to that of conventional SPR sensors. PMID:23299626

Physical examination of the hemodialysis arteriovenous fistula to detect early dysfunction.

PubMed

Abreo, Kenneth; Amin, Bakhtiar M; Abreo, Adrian P

2018-04-01

The maintenance of vascular access patency for end-stage renal disease patients on hemodialysis is necessary for survival. Many nephrologists, nurse practitioners, and nurses have limited experience with the physical examination of the arteriovenous fistula. In this review, we define key terms used in the assessment of an arteriovenous fistula. We discuss the arteriovenous fistula physical exam, including details of inspection, palpation, and auscultation. Using these concepts, we review the abnormal findings that can assist practitioners in determining the location of a stenosis. We review the existing literature that validates physical exam findings with gold standard tests such as ultrasound and angiography. Finally, we review data supporting the value of training physicians and nurses in arteriovenous fistula physical examination.

[Chronic urticaria in childhood : Rational diagnostics and treatment].

PubMed

Ott, H

2017-07-01

Chronic urticaria (CU) is defined by episodes of urticaria with or without angioedema, which recur daily or nearly daily over more than 6 weeks. Sudden manifestations of CU with or without known causes are termed chronic spontaneous urticaria, which is differentiated from chronic inducible urticaria. The differential diagnoses of CU in childhood range from self-limiting dermatoses to severe systemic diseases. Further targeted steps are taken to detect potential trigger factors or underlying illnesses only if suspicion arises on anamnestic grounds and CU is best treated in accordance with international guidelines. First-line therapy consists of non-sedating H 1 -antihistamines at approved or even higher doses. If symptoms persist, additional treatment with omalizumab, cyclosporine or montelukast can be initiated after careful individual consideration.

The Savannah River Site's Groundwater Monitoring Program: Second quarter 1992

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

Rogers, C.D.

1992-10-07

The Environmental Protection Department/Environmental Monitoring Section (EPD/EMS) administers the Savannah River Site's (SRS) Groundwater Monitoring Program. During second quarter 1992, EPD/EMS conducted extensive sampling of monitoring wells. EPD/EMS established two sets of criteria to assist in the management of sample results. The flagging criteria do not define contamination levels; instead, they aid personnel in sample scheduling, interpretation of data, and trend identification. Since 1991, the flagging criteria have been based on the federal Environmental Protection Agency (EPA) drinking water standards and on method detection limits. A detailed explanation of the current flagging criteria is presented in the Flagging Criteria sectionmore » of this document. Analytical results from second quarter 1992 are listed in this report.« less

Error Recovery in the Time-Triggered Paradigm with FTT-CAN.

PubMed

Marques, Luis; Vasconcelos, Verónica; Pedreiras, Paulo; Almeida, Luís

2018-01-11

Data networks are naturally prone to interferences that can corrupt messages, leading to performance degradation or even to critical failure of the corresponding distributed system. To improve resilience of critical systems, time-triggered networks are frequently used, based on communication schedules defined at design-time. These networks offer prompt error detection, but slow error recovery that can only be compensated with bandwidth overprovisioning. On the contrary, the Flexible Time-Triggered (FTT) paradigm uses online traffic scheduling, which enables a compromise between error detection and recovery that can achieve timely recovery with a fraction of the needed bandwidth. This article presents a new method to recover transmission errors in a time-triggered Controller Area Network (CAN) network, based on the Flexible Time-Triggered paradigm, namely FTT-CAN. The method is based on using a server (traffic shaper) to regulate the retransmission of corrupted or omitted messages. We show how to design the server to simultaneously: (1) meet a predefined reliability goal, when considering worst case error recovery scenarios bounded probabilistically by a Poisson process that models the fault arrival rate; and, (2) limit the direct and indirect interference in the message set, preserving overall system schedulability. Extensive simulations with multiple scenarios, based on practical and randomly generated systems, show a reduction of two orders of magnitude in the average bandwidth taken by the proposed error recovery mechanism, when compared with traditional approaches available in the literature based on adding extra pre-defined transmission slots.

Developing tools for the safety specification in risk management plans: lessons learned from a pilot project.

PubMed

Cooper, Andrew J P; Lettis, Sally; Chapman, Charlotte L; Evans, Stephen J W; Waller, Patrick C; Shakir, Saad; Payvandi, Nassrin; Murray, Alison B

2008-05-01

Following the adoption of the ICH E2E guideline, risk management plans (RMP) defining the cumulative safety experience and identifying limitations in safety information are now required for marketing authorisation applications (MAA). A collaborative research project was conducted to gain experience with tools for presenting and evaluating data in the safety specification. This paper presents those tools found to be useful and the lessons learned from their use. Archive data from a successful MAA were utilised. Methods were assessed for demonstrating the extent of clinical safety experience, evaluating the sensitivity of the clinical trial data to detect treatment differences and identifying safety signals from adverse event and laboratory data to define the extent of safety knowledge with the drug. The extent of clinical safety experience was demonstrated by plots of patient exposure over time. Adverse event data were presented using dot plots, which display the percentages of patients with the events of interest, the odds ratio, and 95% confidence interval. Power and confidence interval plots were utilised for evaluating the sensitivity of the clinical database to detect treatment differences. Box and whisker plots were used to display laboratory data. This project enabled us to identify new evidence-based methods for presenting and evaluating clinical safety data. These methods represent an advance in the way safety data from clinical trials can be analysed and presented. This project emphasises the importance of early and comprehensive planning of the safety package, including evaluation of the use of epidemiology data.

Error Recovery in the Time-Triggered Paradigm with FTT-CAN

PubMed Central

Pedreiras, Paulo; Almeida, Luís

2018-01-01

Data networks are naturally prone to interferences that can corrupt messages, leading to performance degradation or even to critical failure of the corresponding distributed system. To improve resilience of critical systems, time-triggered networks are frequently used, based on communication schedules defined at design-time. These networks offer prompt error detection, but slow error recovery that can only be compensated with bandwidth overprovisioning. On the contrary, the Flexible Time-Triggered (FTT) paradigm uses online traffic scheduling, which enables a compromise between error detection and recovery that can achieve timely recovery with a fraction of the needed bandwidth. This article presents a new method to recover transmission errors in a time-triggered Controller Area Network (CAN) network, based on the Flexible Time-Triggered paradigm, namely FTT-CAN. The method is based on using a server (traffic shaper) to regulate the retransmission of corrupted or omitted messages. We show how to design the server to simultaneously: (1) meet a predefined reliability goal, when considering worst case error recovery scenarios bounded probabilistically by a Poisson process that models the fault arrival rate; and, (2) limit the direct and indirect interference in the message set, preserving overall system schedulability. Extensive simulations with multiple scenarios, based on practical and randomly generated systems, show a reduction of two orders of magnitude in the average bandwidth taken by the proposed error recovery mechanism, when compared with traditional approaches available in the literature based on adding extra pre-defined transmission slots. PMID:29324723

A results-based process for evaluation of diverse visual analytics tools

NASA Astrophysics Data System (ADS)

Rubin, Gary; Berger, David H.

2013-05-01

With the pervasiveness of still and full-motion imagery in commercial and military applications, the need to ingest and analyze these media has grown rapidly in recent years. Additionally, video hosting and live camera websites provide a near real-time view of our changing world with unprecedented spatial coverage. To take advantage of these controlled and crowd-sourced opportunities, sophisticated visual analytics (VA) tools are required to accurately and efficiently convert raw imagery into usable information. Whether investing in VA products or evaluating algorithms for potential development, it is important for stakeholders to understand the capabilities and limitations of visual analytics tools. Visual analytics algorithms are being applied to problems related to Intelligence, Surveillance, and Reconnaissance (ISR), facility security, and public safety monitoring, to name a few. The diversity of requirements means that a onesize- fits-all approach to performance assessment will not work. We present a process for evaluating the efficacy of algorithms in real-world conditions, thereby allowing users and developers of video analytics software to understand software capabilities and identify potential shortcomings. The results-based approach described in this paper uses an analysis of end-user requirements and Concept of Operations (CONOPS) to define Measures of Effectiveness (MOEs), test data requirements, and evaluation strategies. We define metrics that individually do not fully characterize a system, but when used together, are a powerful way to reveal both strengths and weaknesses. We provide examples of data products, such as heatmaps, performance maps, detection timelines, and rank-based probability-of-detection curves.

Indocyanine green videoangiography "in negative": definition and usefulness in spinal dural arteriovenous fistulae.

PubMed

Simal Julián, Juan Antonio; Miranda Lloret, Pablo; López González, Antonio; Evangelista Zamora, Rocío; Botella Asunción, Carlos

2013-05-01

Indocyanine green videoangiography (IGV) has proven its effectiveness in the field of exovascular neurosurgery, both in the intracranial and spinal compartment, but is necessary to define a systematic process for the performance of the IGV to facilitate its interpretation during the procedure. We have defined and applied the concept of videoangiography "in negative" (INIGV) to spinal dural arteriovenous fistulae (dAVF) for the detection and treatment of arteriovenous shunts, so called because the first phase is performed with the vessel suggestive of being pathological occluded. A Pentero-operating microscope with near-infrared IGV-integrated system (Carl Zeiss Co., Germany) was used. At our institution, 24 patients were treated for a spinal dAVF between 1995 and 2011, only in the last 4 cases, INIGV was performed. We describe the IGV in negative procedure and show the most illustrative cases. In all cases, the fistula occlusion was confirmed by postoperative selective digital subtraction angiography (DSA). INIGV demonstrate its capacity in detecting vessels not actually arterialized that should be respected and avoid some of the main limitations of the conventional IGV. This is a technical description about an Indocyanine green (ICG) videoangiographic procedure modification that is superior to merely performing ICG before and after clipping of a dAVF. The INIGV results are rapid and easy to interpret procedure and provide great advantages to the dAVF treatment. Nevertheless, further studies are needed with a larger sample size to determine if INIGV may reduce the need to perform immediate postoperative DSA.

J-2X Turbopump Cavitation Diagnostics

NASA Technical Reports Server (NTRS)

Santi, I. Michael; Butas, John P.; Tyler, Thomas R., Jr.; Aguilar, Robert; Sowers, T. Shane

2010-01-01

The J-2X is the upper stage engine currently being designed by Pratt & Whitney Rocketdyne (PWR) for the Ares I Crew Launch Vehicle (CLV). Propellant supply requirements for the J-2X are defined by the Ares Upper Stage to J-2X Interface Control Document (ICD). Supply conditions outside ICD defined start or run boxes can induce turbopump cavitation leading to interruption of J-2X propellant flow during hot fire operation. In severe cases, cavitation can lead to uncontained engine failure with the potential to cause a vehicle catastrophic event. Turbopump and engine system performance models supported by system design information and test data are required to predict existence, severity, and consequences of a cavitation event. A cavitation model for each of the J-2X fuel and oxidizer turbopumps was developed using data from pump water flow test facilities at Pratt & Whitney Rocketdyne (PWR) and Marshall Space Flight Center (MSFC) together with data from Powerpack 1A testing at Stennis Space Center (SSC) and from heritage systems. These component models were implemented within the PWR J-2X Real Time Model (RTM) to provide a foundation for predicting system level effects following turbopump cavitation. The RTM serves as a general failure simulation platform supporting estimation of J-2X redline system effectiveness. A study to compare cavitation induced conditions with component level structural limit thresholds throughout the engine was performed using the RTM. Results provided insight into system level turbopump cavitation effects and redline system effectiveness in preventing structural limit violations. A need to better understand structural limits and redline system failure mitigation potential in the event of fuel side cavitation was indicated. This paper examines study results, efforts to mature J-2X turbopump cavitation models and structural limits, and issues with engine redline detection of cavitation and the use of vehicle-side abort triggers to augment the engine redline system.

Association of Low Lean Mass With Frailty and Physical Performance: A Comparison Between Two Operational Definitions of Sarcopenia-Data From the Berlin Aging Study II (BASE-II).

PubMed

Spira, Dominik; Buchmann, Nikolaus; Nikolov, Jivko; Demuth, Ilja; Steinhagen-Thiessen, Elisabeth; Eckardt, Rahel; Norman, Kristina

2015-06-01

For prevention and treatment of sarcopenia, defined as a decline in lean mass, reliable diagnostic criteria and cutpoints reflecting a clinically relevant threshold are indispensable. As of yet, various parameters have been proposed but no gold standard exists. The aim of this study was to compare cutpoints of appendicular lean mass related to body mass index (ALMBMI) or height (ALM/height(2)) regarding their association with self-reported physical limitations and frailty status in a sample of community-dwelling older adults. A total of 1,343 participants from the Berlin Aging Study II were included. ALM index was assessed with dual-energy X-ray absorptiometry. Limitations in physical performance were assessed via questionnaire and frailty status was defined according to the Fried criteria. In a risk factor-adjusted analysis, participants with an ALMBMI below the cutpoints had 1.4-2.8 times higher odds of difficulties in several domains of physical activity (p = .031 to p < .0001) compared with participants with normal ALMBMI. In participants with low ALM/height(2), no associations with physical limitations were found. Moreover, the odds of being prefrail/frail were statistically significant for the low ALMBMI group only (odds ratio = 2.403, 95% confidence interval: 1.671-3.454, p < .0001) and not for the low ALM/height(2) group. This study showed striking differences between the two operational criteria ALM/height(2) and ALMBMI concerning their association with physical limitations and prefrailty/frailty. The low ALMBMI cutpoints seem suitable to detect patients at risk for negative outcomes such as frailty who might benefit from interventions targeted at improving lean mass. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Visible spectrum-based non-contact HRV and dPTT for stress detection

NASA Astrophysics Data System (ADS)

Kaur, Balvinder; Hutchinson, J. Andrew; Ikonomidou, Vasiliki N.

2017-05-01

Stress is a major health concern that not only compromises our quality of life, but also affects our physical health and well-being. Despite its importance, our ability to objectively detect and quantify it in a real-time, non-invasive manner is very limited. This capability would have a wide variety of medical, military, and security applications. We have developed a pipeline of image and signal processing algorithms to make such a system practical, which includes remote cardiac pulse detection based on visible spectrum videos and physiological stress detection based on the variability in the remotely detected cardiac signals. First, to determine a reliable cardiac pulse, principal component analysis (PCA) was applied for noise reduction and independent component analysis (ICA) was applied for source selection. To determine accurate cardiac timing for heart rate variability (HRV) analysis, a blind source separation method based least squares (LS) estimate was used to determine signal peaks that were closely related to R-peaks of the electrocardiogram (ECG) signal. A new metric, differential pulse transit time (dPTT), defined as the difference in arrival time of the remotely acquired cardiac signal at two separate distal locations, was derived. It was demonstrated that the remotely acquired metrics, HRV and dPTT, have potential for remote stress detection. The developed algorithms were tested against human subject data collected under two physiological conditions using the modified Trier Social Stress Test (TSST) and the Affective Stress Response Test (ASRT). This research provides evidence that the variability in remotely-acquired blood wave (BW) signals can be used for stress (high and mild) detection, and as a guide for further development of a real-time remote stress detection system based on remote HRV and dPTT.

Longitudinal Change Detected by Spectral Domain Optical Coherence Tomography in the Optic Nerve Head and Peripapillary Retina in Experimental Glaucoma

PubMed Central

Strouthidis, Nicholas G.; Fortune, Brad; Yang, Hongli; Sigal, Ian A.

2011-01-01

Purpose. To investigate whether longitudinal changes deep within the optic nerve head (ONH) are detectable by spectral domain optical coherence tomography (SDOCT) in experimental glaucoma (EG) and whether these changes are detectable at the onset of Heidelberg Retina Tomography (HRT; Heidelberg Engineering, Heidelberg, Germany)–defined surface topography depression. Methods. Longitudinal SDOCT imaging (Spectralis; Heidelberg Engineering) was performed in both eyes of nine rhesus macaques every 1 to 3 weeks. One eye of each underwent trabecular laser-induced IOP elevation. Four masked operators delineated internal limiting membrane (ILM), retinal nerve fiber layer (RNFL), Bruch's membrane/retinal pigment epithelium (BM/RPE), neural canal opening (NCO), and anterior lamina cribrosa surface (ALCS) by using custom software. Longitudinal changes were assessed and compared between the EG and control (nonlasered) eyes at the onset of HRT-detected surface depression (follow-up 1; [FU1]) and at the most recent image (follow-up 2; [FU2]). Results. Mean IOP in EG eyes was 7.1 to 24.6 mm Hg at FU1 and 13.5 to 31.9 mm Hg at FU2. In control eyes, the mean IOP was 7.2 to 12.6 mm Hg (FU1) and 8.9 to 16.0 mm Hg (FU2). At FU1, neuroretinal rim decreased and ALCS depth increased significantly (paired t-test, P < 0.01); no change in RNFL thickness was detected. At FU2, however, significant prelaminar tissue thinning, posterior displacement of NCO, and RNFL thinning were observed. Conclusions. Longitudinal SDOCT imaging can detect deep ONH changes in EG eyes, the earliest of which are present at the onset of HRT-detected ONH surface height depression. These parameters represent realistic targets for SDOCT detection of glaucomatous progression in human subjects. PMID:21217108

Differential Item Functioning Detection Across Two Methods of Defining Group Comparisons

PubMed Central

Sari, Halil Ibrahim

2014-01-01

This study compares two methods of defining groups for the detection of differential item functioning (DIF): (a) pairwise comparisons and (b) composite group comparisons. We aim to emphasize and empirically support the notion that the choice of pairwise versus composite group definitions in DIF is a reflection of how one defines fairness in DIF studies. In this study, a simulation was conducted based on data from a 60-item ACT Mathematics test (ACT; Hanson & Béguin). The unsigned area measure method (Raju) was used as the DIF detection method. An application to operational data was also completed in the study, as well as a comparison of observed Type I error rates and false discovery rates across the two methods of defining groups. Results indicate that the amount of flagged DIF or interpretations about DIF in all conditions were not the same across the two methods, and there may be some benefits to using composite group approaches. The results are discussed in connection to differing definitions of fairness. Recommendations for practice are made. PMID:29795837

Re-evaluation of groundwater monitoring data for glyphosate and bentazone by taking detection limits into account.

PubMed

Hansen, Claus Toni; Ritz, Christian; Gerhard, Daniel; Jensen, Jens Erik; Streibig, Jens Carl

2015-12-01

Current regulatory assessment of pesticide contamination of Danish groundwater is exclusively based on samples with pesticide concentrations above detection limit. Here we demonstrate that a realistic quantification of pesticide contamination requires the inclusion of "non-detect" samples i.e. samples with concentrations below the detection limit, as left-censored observations. The median calculated pesticide concentrations are shown to be reduced 10(4) to 10(5) fold for two representative herbicides (glyphosate and bentazone) relative to the median concentrations based upon observations above detection limits alone. Copyright © 2015 Elsevier B.V. All rights reserved.

A Methodological Framework for Model Selection in Interrupted Time Series Studies.

PubMed

Lopez Bernal, J; Soumerai, S; Gasparrini, A

2018-06-06

Interrupted time series is a powerful and increasingly popular design for evaluating public health and health service interventions. The design involves analysing trends in the outcome of interest and estimating the change in trend following an intervention relative to the counterfactual (the expected ongoing trend if the intervention had not occurred). There are two key components to modelling this effect: first, defining the counterfactual; second, defining the type of effect that the intervention is expected to have on the outcome, known as the impact model. The counterfactual is defined by extrapolating the underlying trends observed before the intervention to the post-intervention period. In doing this, authors must consider the pre-intervention period that will be included, any time varying confounders, whether trends may vary within different subgroups of the population and whether trends are linear or non-linear. Defining the impact model involves specifying the parameters that model the intervention, including for instance whether to allow for an abrupt level change or a gradual slope change, whether to allow for a lag before any effect on the outcome, whether to allow a transition period during which the intervention is being implemented and whether a ceiling or floor effect might be expected. Inappropriate model specification can bias the results of an interrupted time series analysis and using a model that is not closely tailored to the intervention or testing multiple models increases the risk of false positives being detected. It is important that authors use substantive knowledge to customise their interrupted time series model a priori to the intervention and outcome under study. Where there is uncertainty in model specification, authors should consider using separate data sources to define the intervention, running limited sensitivity analyses or undertaking initial exploratory studies. Copyright © 2018. Published by Elsevier Inc.

Enhanced spectrophotometric detection of Hg in water samples by surface plasmon resonance of Au nanoparticles after preconcentration with vortex-assisted liquid-liquid microextraction

NASA Astrophysics Data System (ADS)

Martinis, Estefanía M.; Wuilloud, Rodolfo G.

2016-10-01

This article presents an efficient, simple, and cost-effective method for the determination of trace amounts of Hg by vortex-assisted liquid-liquid microextraction (VALLME) coupled to microvolume UV-Vis spectrophotometry. This method correlates changes in the intensity of localized surface plasmon resonance (LSPR) of tetraoctylammonium bromide (TOABr) coated Au nanoparticles (NPs) after interaction with Hg2+ ion. Spectroscopic measurements of the TOABr-coated Au NPs phase with particular absorption properties (strong and well-defined absorption bands) after analyte extraction by VALLME, provide an accurate and sensitive determination of Hg in water samples, comparable with measurements obtained by atomic absorption spectrometry (AAS). Different variables including sample volume, extraction time, and TOABr-coated Au NPs dispersion volume were carefully studied; final experimental conditions were 5 mL, 120 μL and 5 min respectively. The limit of detection (LOD) was 0.8 ng mL- 1. The calibration curve was linear at concentrations between the limit of quantification (LOQ) (4.9 ng mL- 1) and up to at least 120 ng mL- 1 of Hg. The relative standard deviation for six replicate determinations of 20 ng mL- 1 of Hg was 4.7%. This method exhibited an excellent analytical performance in terms of selectivity and sensitivity and it was finally applied for Hg determination in spiked tap and mineral water samples.

Modeling the Dynamics of High-Grade Serous Ovarian Cancer Progression for Transvaginal Ultrasound-Based Screening and Early Detection

PubMed Central

Lee, Jung-Min; Levy, Doron

2016-01-01

High-grade serous ovarian cancer (HGSOC) represents the majority of ovarian cancers and accounts for the largest proportion of deaths from the disease. A timely detection of low volume HGSOC should be the goal of any screening studies. However, numerous transvaginal ultrasound (TVU) detection-based population studies aimed at detecting low-volume disease have not yielded reduced mortality rates. A quantitative invalidation of TVU as an effective HGSOC screening strategy is a necessary next step. Herein, we propose a mathematical model for a quantitative explanation on the reported failure of TVU-based screening to improve HGSOC low-volume detectability and overall survival.We develop a novel in silico mathematical assessment of the efficacy of a unimodal TVU monitoring regimen as a strategy aimed at detecting low-volume HGSOC in cancer-positive cases, defined as cases for which the inception of the first malignant cell has already occurred. Our findings show that the median window of opportunity interval length for TVU monitoring and HGSOC detection is approximately 1.76 years. This does not translate into reduced mortality levels or improved detection accuracy in an in silico cohort across multiple TVU monitoring frequencies or detection sensitivities. We demonstrate that even a semiannual, unimodal TVU monitoring protocol is expected to miss detectable HGSOC. Lastly, we find that circa 50% of the simulated HGSOC growth curves never reach the baseline detectability threshold, and that on average, 5–7 infrequent, rate-limiting stochastic changes in the growth parameters are associated with reaching HGSOC detectability and mortality thresholds respectively. Focusing on a malignancy poorly studied in the mathematical oncology community, our model captures the dynamic, temporal evolution of HGSOC progression. Our mathematical model is consistent with recent case reports and prospective TVU screening population studies, and provides support to the empirical recommendation against frequent HGSOC screening. PMID:27257824

49 CFR 71.1 - Limits defined; exceptions authorized for certain rail operating purposes only.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation STANDARD TIME ZONE BOUNDARIES § 71.1 Limits defined; exceptions authorized for certain rail... zones established by section 1 of the Standard Time Act, as amended by section 4 of the Uniform Time Act... carriers, whose operations cross the time zone boundaries prescribed by this part, authorizing them to...

40 CFR Table 3 to Subpart Jjjjjj... - Operating Limits for Boilers With Emission Limits

Code of Federal Regulations, 2013 CFR

2013-07-01

... as defined in § 63.11237. 4. Dry sorbent or activated carbon injection control Maintain the 30-day rolling average sorbent or activated carbon injection rate at or above the minimum sorbent injection rate or minimum activated carbon injection rate as defined in § 63.11237. When your boiler operates at...

Defining and Applying Limits for Test and Flight Through the Project Lifecycle GSFC Standard. [Scope: Non-Cryogenic Systems Tested in Vacuum

NASA Technical Reports Server (NTRS)

Mosier, Carol

2015-01-01

The presentation will be given at the Annual Thermal Fluids Analysis Workshop (TFAWS 2015, NCTS 21070-15) hosted by the Goddard SpaceFlight Center (GSFC) Thermal Engineering Branch (Code 545). The powerpoint presentation details the process of defining limits throughout the lifecycle of a flight project.

Detection of Shielded Nuclear Material in a Cargo Container

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

J. L. Jones; D. R. Norman; K. J. Haskell

The Idaho National Laboratory, along with Los Alamos National Laboratory and the Idaho State University’s Idaho Accelerator Center, are developing electron accelerator-based, photonuclear inspection technologies for the detection of shielded nuclear material within air-, rail-, and especially, maritime-cargo transportation containers. This paper describes a developing prototypical cargo container inspection system utilizing the Pulsed Photonuclear Assessment (PPA) technology, incorporates interchangeable, well-defined, contraband shielding structures (i.e., "calibration" pallets) providing realistic detection data for induced radiation signatures from smuggled nuclear material, and provides various shielded nuclear material detection results. Using a 4.8-kg quantity of depleted uranium, neutron and gamma-ray detection responses are presentedmore » for well-defined shielded and unshielded configurations evaluated in a selected cargo container inspection configuration. © 2001 Elsevier Science. All rights reserved« less

An electrochemiluminescence biosensor for endonuclease EcoRI detection.

PubMed

Li, Yingjie; Li, Yuqin; Wu, Yaoyu; Lu, Fushen; Chen, Yaowen; Gao, Wenhua

2017-03-15

Endonucleases cleavage of DNA plays an important role in biological and medicinal chemistry. This work was going to develop a reliable and sensitive electrochemiluminescent (ECL) biosensor for detecting endonucleases by using gold nanoparticles graphene composite (GNPs-graphene) as a signal amplifier. Firstly, the GNPs and graphene were simultaneously deposited on the glassy carbon electrode (GCE) by cyclic voltammetry. Then a stem DNA was anchored on the surface of GCE. And with a modifying DNA introduced into the electrode by DNA assembly, a strong ECL signal was obtained. After a DNA modified with ferrocene assembly to the stem DNA, the ECL signal had a sharp decrease due to the quench effect of ferrocene to and the biosensor comes into being a "off" state. With the effect of endonuclease, the ECL signal had a recovery because of the ferrocene being released and the biosensor formed a "on" state. Moreover, the recovery of ECL signal was related to the concentration of endonucleases. Combining specific defined DNA and endonuclease, this method has a potential to detect different endonucleases. In this work, we took the EcoRI as an example to identify the feasibility of ECL biosensor in applying in sensitive detection of endonucleases using a GNPs-graphene signal amplifier. Under optimal condition, the proposed biosensor obtained a low limit of detection (LOD) 5.6×10 -5 UmL -1 . And the stability, selectivity and reproducibility of the biosensor also were researched. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel paper-based device coupled with a silver nanoparticle-modified boron-doped diamond electrode for cholesterol detection.

PubMed

Nantaphol, Siriwan; Chailapakul, Orawon; Siangproh, Weena

2015-09-03

A novel paper-based analytical device (PAD) coupled with a silver nanoparticle-modified boron-doped diamond (AgNP/BDD) electrode was first developed as a cholesterol sensor. The AgNP/BDD electrode was used as working electrode after modification by AgNPs using an electrodeposition method. Wax printing was used to define the hydrophilic and hydrophobic areas on filter paper, and then counter and reference electrodes were fabricated on the hydrophilic area by screen-printing in house. For the amperometric detection, cholesterol and cholesterol oxidase (ChOx) were directly drop-cast onto the hydrophilic area, and H2O2 produced from the enzymatic reaction was monitored. The fabricated device demonstrated a good linearity (0.39 mg dL(-1) to 270.69 mg dL(-1)), low detection limit (0.25 mg dL(-1)), and high sensitivity (49.61 μA mM(-1) cm(-2)). The precision value for ten replicates was 3.76% RSD for 1 mM H2O2. In addition, this biosensor exhibited very high selectivity for cholesterol detection and excellent recoveries for bovine serum analysis (in the range of 99.6-100.8%). The results showed that this new sensing platform will be an alternative tool for cholesterol detection in routine diagnosis and offers the advantages of low sample/reagent consumption, low cost, portability, and short analysis time. Copyright © 2015 Elsevier B.V. All rights reserved.

The Use of COLD-PCR and High-Resolution Melting Analysis Improves the Limit of Detection of KRAS and BRAF Mutations in Colorectal Cancer

PubMed Central

Mancini, Irene; Santucci, Claudio; Sestini, Roberta; Simi, Lisa; Pratesi, Nicola; Cianchi, Fabio; Valanzano, Rosa; Pinzani, Pamela; Orlando, Claudio

2010-01-01

Fast and reliable tests to detect mutations in human cancers are required to better define clinical samples and orient targeted therapies. KRAS mutations occur in 30–50% of colorectal cancers (CRCs) and represent a marker of clinical resistance to cetuximab therapy. In addition, the BRAF V600E is mutated in about 10% of CRCs, and the development of a specific inhibitor of mutant BRAF kinase has prompted a growing interest in BRAFV600E detection. Traditional methods, such as PCR and direct sequencing, do not detect low-level mutations in cancer, resulting in false negative diagnoses. In this study, we designed a protocol to detect mutations of KRAS and BRAFV600E in 117 sporadic CRCs based on coamplification at lower denaturation temperature PCR (COLD-PCR) and high-resolution melting (HRM). Using traditional PCR and direct sequencing, we found KRAS mutations in 47 (40%) patients and BRAFV600E in 10 (8.5%). The use of COLD-PCR in apparently wild-type samples allowed us to identify 15 newly mutated CRCs (10 for KRAS and 5 for BRAFV600E), raising the percentage of mutated CRCs to 48.7% for KRAS and to 12.8% for BRAFV600E. Therefore, COLD-PCR combined with HRM permits the correct identification of less represented mutations in CRC and better selection of patients eligible for targeted therapies, without requiring expensive and time-consuming procedures. PMID:20616366

Galaxy And Mass Assembly (GAMA): detection of low-surface-brightness galaxies from SDSS data

NASA Astrophysics Data System (ADS)

Williams, Richard P.; Baldry, I. K.; Kelvin, L. S.; James, P. A.; Driver, S. P.; Prescott, M.; Brough, S.; Brown, M. J. I.; Davies, L. J. M.; Holwerda, B. W.; Liske, J.; Norberg, P.; Moffett, A. J.; Wright, A. H.

2016-12-01

We report on a search for new low-surface-brightness galaxies (LSBGs) using Sloan Digital Sky Survey (SDSS) data within the Galaxy And Mass Assembly (GAMA) equatorial fields. The search method consisted of masking objects detected with SDSS PHOTO, combining gri images weighted to maximize the expected signal-to-noise ratio, and smoothing the images. The processed images were then run through a detection algorithm that finds all pixels above a set threshold and groups them based on their proximity to one another. The list of detections was cleaned of contaminants such as diffraction spikes and the faint wings of masked objects. From these, selecting potentially the brightest in terms of total flux, a list of 343 LSBGs was produced having been confirmed using VISTA Kilo-degree Infrared Galaxy Survey (VIKING) imaging. The photometry of this sample was refined using the deeper VIKING Z band as the aperture-defining band. Measuring their g - I and J - K colours shows that most are consistent with being at redshifts less than 0.2. The photometry is carried out using an AUTO aperture for each detection giving surface brightnesses of μr ≳ 25 mag arcsec-2 and magnitudes of r > 19.8 mag. None of these galaxies are bright enough to be within the GAMA main survey limit but could be part of future deeper surveys to measure the low-mass end of the galaxy stellar mass function.

Modular nucleic acid assembled p/MHC microarrays for multiplexed sorting of antigen-specific T cells.

PubMed

Kwong, Gabriel A; Radu, Caius G; Hwang, Kiwook; Shu, Chengyi J; Ma, Chao; Koya, Richard C; Comin-Anduix, Begonya; Hadrup, Sine Reker; Bailey, Ryan C; Witte, Owen N; Schumacher, Ton N; Ribas, Antoni; Heath, James R

2009-07-22

The human immune system consists of a large number of T cells capable of recognizing and responding to antigens derived from various sources. The development of peptide-major histocompatibility (p/MHC) tetrameric complexes has enabled the direct detection of these antigen-specific T cells. With the goal of increasing throughput and multiplexing of T cell detection, protein microarrays spotted with defined p/MHC complexes have been reported, but studies have been limited due to the inherent instability and reproducibility of arrays produced via conventional spotted methods. Herein, we report on a platform for the detection of antigen-specific T cells on glass substrates that offers significant advantages over existing surface-bound schemes. In this approach, called "Nucleic Acid Cell Sorting (NACS)", single-stranded DNA oligomers conjugated site-specifically to p/MHC tetramers are employed to immobilize p/MHC tetramers via hybridization to a complementary-printed substrate. Fully assembled p/MHC arrays are used to detect and enumerate T cells captured from cellular suspensions, including primary human T cells collected from cancer patients. NACS arrays outperform conventional spotted arrays assessed in key criteria such as repeatability and homogeneity. The versatility of employing DNA sequences for cell sorting is exploited to enable the programmed, selective release of target populations of immobilized T cells with restriction endonucleases for downstream analysis. Because of the performance, facile and modular assembly of p/MHC tetramer arrays, NACS holds promise as a versatile platform for multiplexed T cell detection.

Assessing agreement between malaria slide density readings.

PubMed

Alexander, Neal; Schellenberg, David; Ngasala, Billy; Petzold, Max; Drakeley, Chris; Sutherland, Colin

2010-01-04

Several criteria have been used to assess agreement between replicate slide readings of malaria parasite density. Such criteria may be based on percent difference, or absolute difference, or a combination. Neither the rationale for choosing between these types of criteria, nor that for choosing the magnitude of difference which defines acceptable agreement, are clear. The current paper seeks a procedure which avoids the disadvantages of these current options and whose parameter values are more clearly justified. Variation of parasite density within a slide is expected, even when it has been prepared from a homogeneous sample. This places lower limits on sensitivity and observer agreement, quantified by the Poisson distribution. This means that, if a criterion of fixed percent difference criterion is used for satisfactory agreement, the number of discrepant readings is over-estimated at low parasite densities. With a criterion of fixed absolute difference, the same happens at high parasite densities. For an ideal slide, following the Poisson distribution, a criterion based on a constant difference in square root counts would apply for all densities. This can be back-transformed to a difference in absolute counts, which, as expected, gives a wider range of acceptable agreement at higher average densities. In an example dataset from Tanzania, observed differences in square root counts correspond to a 95% limits of agreement of -2,800 and +2,500 parasites/microl at average density of 2,000 parasites/microl, and -6,200 and +5,700 parasites/microl at 10,000 parasites/microl. However, there were more outliers beyond those ranges at higher densities, meaning that actual coverage of these ranges was not a constant 95%, but decreased with density. In a second study, a trial of microscopist training, the corresponding ranges of agreement are wider and asymmetrical: -8,600 to +5,200/microl, and -19,200 to +11,700/microl, respectively. By comparison, the optimal limits of agreement, corresponding to Poisson variation, are +/- 780 and +/- 1,800 parasites/microl, respectively. The focus of this approach on the volume of blood read leads to other conclusions. For example, no matter how large a volume of blood is read, some densities are too low to be reliably detected, which in turn means that disagreements on slide positivity may simply result from within-slide variation, rather than reading errors. The proposed method defines limits of acceptable agreement in a way which allows for the natural increase in variability with parasite density. This includes defining the levels of between-reader variability, which are consistent with random variation: disagreements within these limits should not trigger additional readings. This approach merits investigation in other settings, in order to determine both the extent of its applicability, and appropriate numerical values for limits of agreement.

Task-oriented quality assessment and adaptation in real-time mission critical video streaming applications

NASA Astrophysics Data System (ADS)

Nightingale, James; Wang, Qi; Grecos, Christos

2015-02-01

In recent years video traffic has become the dominant application on the Internet with global year-on-year increases in video-oriented consumer services. Driven by improved bandwidth in both mobile and fixed networks, steadily reducing hardware costs and the development of new technologies, many existing and new classes of commercial and industrial video applications are now being upgraded or emerging. Some of the use cases for these applications include areas such as public and private security monitoring for loss prevention or intruder detection, industrial process monitoring and critical infrastructure monitoring. The use of video is becoming commonplace in defence, security, commercial, industrial, educational and health contexts. Towards optimal performances, the design or optimisation in each of these applications should be context aware and task oriented with the characteristics of the video stream (frame rate, spatial resolution, bandwidth etc.) chosen to match the use case requirements. For example, in the security domain, a task-oriented consideration may be that higher resolution video would be required to identify an intruder than to simply detect his presence. Whilst in the same case, contextual factors such as the requirement to transmit over a resource-limited wireless link, may impose constraints on the selection of optimum task-oriented parameters. This paper presents a novel, conceptually simple and easily implemented method of assessing video quality relative to its suitability for a particular task and dynamically adapting videos streams during transmission to ensure that the task can be successfully completed. Firstly we defined two principle classes of tasks: recognition tasks and event detection tasks. These task classes are further subdivided into a set of task-related profiles, each of which is associated with a set of taskoriented attributes (minimum spatial resolution, minimum frame rate etc.). For example, in the detection class, profiles for intruder detection will require different temporal characteristics (frame rate) from those used for detection of high motion objects such as vehicles or aircrafts. We also define a set of contextual attributes that are associated with each instance of a running application that include resource constraints imposed by the transmission system employed and the hardware platforms used as source and destination of the video stream. Empirical results are presented and analysed to demonstrate the advantages of the proposed schemes.

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

PubMed Central

Brencic, Anja; Winans, Stephen C.

2005-01-01

Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described. PMID:15755957

Driver behavior at rail-highway grade crossings : a signal detection theory analysis

DOT National Transportation Integrated Search

1996-01-01

Signal Detection Theory (SDT) is often used in studies of sensory psychology and perception to describe laboratory experiments in which subjects are asked to detect small changes in very wellcontrolled, precisely defined stimuli such as the intensity...

Swallowable fluorometric capsule for wireless triage of gastrointestinal bleeding.

PubMed

Nemiroski, A; Ryou, M; Thompson, C C; Westervelt, R M

2015-12-07

Real-time detection of gastrointestinal bleeding remains a major challenge because there does not yet exist a minimally invasive technology that can both i) monitor for blood from an active hemorrhage and ii) uniquely distinguish it from blood left over from an inactive hemorrhage. Such a device would be an important tool for clinical triage. One promising solution, which we have proposed previously, is to inject a fluorescent dye into the blood stream and to use it as a distinctive marker of active bleeding by monitoring leakage into the gastrointestinal tract with a wireless fluorometer. This paper reports, for the first time to our knowledge, the development of a swallowable, wireless capsule with a built-in fluorometer capable of detecting fluorescein in blood, and intended for monitoring gastrointestinal bleeding in the stomach. The embedded, compact fluorometer uses pinholes to define a microliter sensing volume and to eliminate bulky optical components. The proof-of-concept capsule integrates optics, low-noise analog sensing electronics, a microcontroller, battery, and low power Zigbee radio, all into a cylindrical package measuring 11 mm × 27 mm and weighing 10 g. Bench-top experiments demonstrate wireless fluorometry with a limit-of-detection of 20 nM aqueous fluorescein. This device represents a major step towards a technology that would enable simple, rapid detection of active gastrointestinal bleeding, a capability that would save precious time and resources and, ultimately, reduce complications in patients.

Silk provides a new avenue for third generation biosensors: Sensitive, selective and stable electrochemical detection of nitric oxide.

PubMed

Musameh, Mustafa M; Dunn, Christopher J; Uddin, Md Hemayet; Sutherland, Tara D; Rapson, Trevor D

2018-04-30

Using heme entrapped in recombinant silk films, we have produced 3rd generation biosensors, which allow direct electron transfer from the heme center to an electrode avoiding the need for electron mediators. Here, we demonstrate the use of these heme-silk films for the detection of nitric oxide (NO) at nanomolar levels in the presence and absence of oxygen. The sensor was prepared by drop-casting a silk solution on a glassy carbon electrode modified with multiwalled carbon nanotubes (MWCNT) followed by infusion with heme. The sensor was characterized by cyclic voltammetry and showed well defined and reversible Fe + / Fe 3+ redox couple activity, with NO detection by oxidation at potentials above +0.45V or reduction at potentials below - 0.7V. Evaluation of the effect of pH on the sensor response to NO reduction indicated a maximum response at pH 3. The sensor showed good linearity in the concentration range from 19 to 190nM (R 2 = 0.99) with a detection limit of 2nM. The sensor had excellent selectivity towards NO with no or negligible interference from oxygen, nitrite, nitrate, dopamine and ascorbic acid and retained 86% of response after 2 months of operation and storage at room temperature. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Speech-in-Noise Tests and Supra-threshold Auditory Evoked Potentials as Metrics for Noise Damage and Clinical Trial Outcome Measures.

PubMed

Le Prell, Colleen G; Brungart, Douglas S

2016-09-01

In humans, the accepted clinical standards for detecting hearing loss are the behavioral audiogram, based on the absolute detection threshold of pure-tones, and the threshold auditory brainstem response (ABR). The audiogram and the threshold ABR are reliable and sensitive measures of hearing thresholds in human listeners. However, recent results from noise-exposed animals demonstrate that noise exposure can cause substantial neurodegeneration in the peripheral auditory system without degrading pure-tone audiometric thresholds. It has been suggested that clinical measures of auditory performance conducted with stimuli presented above the detection threshold may be more sensitive than the behavioral audiogram in detecting early-stage noise-induced hearing loss in listeners with audiometric thresholds within normal limits. Supra-threshold speech-in-noise testing and supra-threshold ABR responses are reviewed here, given that they may be useful supplements to the behavioral audiogram for assessment of possible neurodegeneration in noise-exposed listeners. Supra-threshold tests may be useful for assessing the effects of noise on the human inner ear, and the effectiveness of interventions designed to prevent noise trauma. The current state of the science does not necessarily allow us to define a single set of best practice protocols. Nonetheless, we encourage investigators to incorporate these metrics into test batteries when feasible, with an effort to standardize procedures to the greatest extent possible as new reports emerge.

Wireless tamper detection sensor and sensing system

NASA Technical Reports Server (NTRS)

Woodard, Stanley E. (Inventor); Taylor, Bryant D. (Inventor)

2011-01-01

A wireless tamper detection sensor is defined by a perforated electrical conductor. The conductor is shaped to form a geometric pattern between first and second ends thereof such that the conductor defines an open-circuit that can store and transfer electrical and magnetic energy. The conductor resonates in the presence of a time-varying magnetic field to generate a harmonic response. The harmonic response changes when the conductor experiences a change in its geometric pattern due to severing of the conductor along at least a portion of the perforations. A magnetic field response recorder is used to wirelessly transmit the time-varying magnetic field and wirelessly detecting the conductor's harmonic response.

Historical development of limits of acceptable change: conceptual clarifications and possible extensions

Treesearch

David N. Cole; George H. Stankey

1997-01-01

The Limits of Acceptable Change (LAC) process was developed to deal with the issue of recreational carrying capacity. For that purpose, the LAC process sought to explicitly define a compromise between resource/visitor experience protection and recreation use goals. The most critical and unique element of the process is the specification of LAC standards that define...

Defining fire and wilderness objectives: Applying limits of acceptable change

Treesearch

David N. Cole

1995-01-01

The Limits of Acceptable Change (LAC) planning process was developed to help define objectives for recreation management in wilderness. This process can be applied to fire in wilderness if its conceptual foundation is broadened. LAC would lead decision makers to identify a compromise between the goal of allowing fire to play its natural role in wilderness and various...

LIMITATIONS ON THE USES OF MULTIMEDIA EXPOSURE MEASUREMENTS FOR MULTIPATHWAY EXPOSURE ASSESSMENT - PART I: HANDLING OBSERVATIONS BELOW DETECTION LIMITS

EPA Science Inventory

Multimedia data from two probability-based exposure studies were investigated in terms of how censoring of non-detects affected estimation of population parameters and associations. Appropriate methods for handling censored below-detection-limit (BDL) values in this context were...

Use of surface-geophysical methods to assess riverbed scour at bridge piers

USGS Publications Warehouse

Gorin, S.R.; Haeni, F.P.

1989-01-01

A ground-penetrating-radar system, and three seismic systems--color fathometer, tuned transducer, and black-and-white fathometer--were used to evaluate river-bed scour at the Charter Oak, Founder 's and Bulkeley Bridges in Hartford, Connecticut. Cross-sections of the channel and some lateral sections were run at each bridge in June and July 1987, and significant scour at piers supporting each of these bridges was recorded. Each of the four geophysical systems proved to have advantages and limitations. The ground penetrating radar system used single and dual 80 megahertz antennae floating in the water to transmit and receive the signal. The method was successful in water less than 25 ft deep, and in resistive earth materials. The geometry of existing scour holes and the extent of post-scour sedimentation were clearly defined. The color fathometer, operating at a signal frequency of 20 kilohertz, delineated existing scour-hole geometry, detected infilling of scour holes, and provided qualitative information about the physical properties of sediments. The tuned transducer, operating at a signal frequency of 14 kilohertz, defined scour-hole geometry and the extent of post-scour sediment deposition. Both of these systems were effective in water greater than 5 ft deep. At a signal frequency of 200 kilohertz, the black-and-white fathometer could not penetrate post-scour deposits, but it was useful in defining existing scour-holed geometry in water of any depth. (USGS)

Phylogenetic continuum indicates "galaxies" in the protein universe: preliminary results on the natural group structures of proteins.

PubMed

Ladunga, I

1992-04-01

The markedly nonuniform, even systematic distribution of sequences in the protein "universe" has been analyzed by methods of protein taxonomy. Mapping of the natural hierarchical system of proteins has revealed some dense cores, i.e., well-defined clusterings of proteins that seem to be natural structural groupings, possibly seeds for a future protein taxonomy. The aim was not to force proteins into more or less man-made categories by discriminant analysis, but to find structurally similar groups, possibly of common evolutionary origin. Single-valued distance measures between pairs of superfamilies from the Protein Identification Resource were defined by two chi 2-like methods on tripeptide frequencies and the variable-length subsequence identity method derived from dot-matrix comparisons. Distance matrices were processed by several methods of cluster analysis to detect phylogenetic continuum between highly divergent proteins. Only well-defined clusters characterized by relatively unique structural, intracellular environmental, organismal, and functional attribute states were selected as major protein groups, including subsets of viral and Escherichia coli proteins, hormones, inhibitors, plant, ribosomal, serum and structural proteins, amino acid synthases, and clusters dominated by certain oxidoreductases and apolar and DNA-associated enzymes. The limited repertoire of functional patterns due to small genome size, the high rate of recombination, specific features of the bacterial membranes, or of the virus cycle canalize certain proteins of viruses and Gram-negative bacteria, respectively, to organismal groups.

9 CFR 94.0 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... detected, had in place prior to the detection of BSE in an indigenous ruminant, risk mitigation measures... kept. Region. Any defined geographic land area identifiable by geological, political, or surveyed...

Ground-based detectability of terrestrial and Jovian extrasolar planets: observations of CM Draconis at Lick Observatory.

PubMed

Doyle, L R; Dunham, E T; Deeg, H J; Blue, J E; Jenkins, J M

1996-06-25

The detection of terrestrial-sized extrasolar planets from the ground has been thought to be virtually impossible due to atmospheric scintillation limits. However, we show that this is not the case especially selected (but nevertheless main sequence) stars, namely small eclipsing binaries. For the smallest of these systems, CM Draconis, several months to a few years of photometric observations with 1-m-class telescopes will be sufficient to detect the transits of any short-period planets of sizes > or = 1.5 Earth radii (RE), using cross-correlation analysis with moderately good photometry. Somewhat larger telescopes will be needed to extend this detectability to terrestrial planets in larger eclipsing binary systems. (We arbitrarily define "terrestrial planets" herein as those whose disc areas are closer to that of Earth's than Neptune's i.e., less than about 2.78 RE.) As a "spin-off" of such observations, we will also be able to detect the presence of Jovian-mass planets without transits using the timing of the eclipse minima. Eclipse minima will drift in time as the binary system is offset by a sufficiently massive planet (i.e., one Jupiter mass) about the binary/giant-planet barycenter, causing a periodic variation in the light travel time to the observer. We present here an outline of present observations taking place at the University of California Lick Observatory using the Crossley 0.9-m telescope in collaboration with other observatories (in South Korea, Crete, France, Canary Islands, and New York) to detect or constrain the existence of terrestrial planets around main sequence eclipsing binary star systems, starting with CM Draconis. We demonstrate the applicability of photometric data to the general detection of gas giant planets via eclipse minima timings in many other small-mass eclipsing binary systems as well.

Rapid response radiation sensors for homeland security applications

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sanjoy; Maurer, Richard; Guss, Paul

2014-09-01

The National Security Technologies, LLC, Remote Sensing Laboratory is developing a rapid response radiation detection system for homeland security field applications. The intelligence-driven system is deployed only when non-radiological information about the target is verifiable. The survey area is often limited, so the detection range is small; in most cases covering a distance of 10 meters or less suffices. Definitive response is required in no more than 3 seconds and should minimize false negative alarms, but can err on the side of positive false alarms. The detection system is rapidly reconfigurable in terms of size, shape, and outer appearance; it is a plug-and-play system. Multiple radiation detection components (viz., two or more sodium iodide scintillators) are used to independently "over-determine" the existence of the threat object. Rapid response electronic dose rate meters are also included in the equipment suite. Carefully studied threat signatures are the basis of the decision making. The use of Rad-Detect predictive modeling provides information on the nature of the threat object. Rad-Detect provides accurate dose rate from heavily shielded large sources; for example those lost in Mexico were Category 1 radiation sources (~3,000 Ci of 60Co), the most dangerous of five categories defined by the International Atomic Energy Agency. Taken out of their shielding containers, Category 1 sources can kill anyone who is exposed to them at close range for a few minutes to an hour. Whenever possible sub-second data acquisition will be attempted, and, when deployed, the system will be characterized for false alarm rates. Although the radiation detection materials selected are fast (viz., faster scintillators), their speed is secondary to sensitivity, which is of primary importance. Results from these efforts will be discussed and demonstrated.

Ground-based detectability of terrestrial and Jovian extrasolar planets: observations of CM Draconis at Lick Observatory

NASA Technical Reports Server (NTRS)

Doyle, L. R.; Dunham, E. T.; Deeg, H. J.; Blue, J. E.; Jenkins, J. M.

1996-01-01

The detection of terrestrial-sized extrasolar planets from the ground has been thought to be virtually impossible due to atmospheric scintillation limits. However, we show that this is not the case especially selected (but nevertheless main sequence) stars, namely small eclipsing binaries. For the smallest of these systems, CM Draconis, several months to a few years of photometric observations with 1-m-class telescopes will be sufficient to detect the transits of any short-period planets of sizes > or = 1.5 Earth radii (RE), using cross-correlation analysis with moderately good photometry. Somewhat larger telescopes will be needed to extend this detectability to terrestrial planets in larger eclipsing binary systems. (We arbitrarily define "terrestrial planets" herein as those whose disc areas are closer to that of Earth's than Neptune's i.e., less than about 2.78 RE.) As a "spin-off" of such observations, we will also be able to detect the presence of Jovian-mass planets without transits using the timing of the eclipse minima. Eclipse minima will drift in time as the binary system is offset by a sufficiently massive planet (i.e., one Jupiter mass) about the binary/giant-planet barycenter, causing a periodic variation in the light travel time to the observer. We present here an outline of present observations taking place at the University of California Lick Observatory using the Crossley 0.9-m telescope in collaboration with other observatories (in South Korea, Crete, France, Canary Islands, and New York) to detect or constrain the existence of terrestrial planets around main sequence eclipsing binary star systems, starting with CM Draconis. We demonstrate the applicability of photometric data to the general detection of gas giant planets via eclipse minima timings in many other small-mass eclipsing binary systems as well.

Health Service Utilisation, Detection Rates by Family Practitioners, and Management of Patients with Common Mental Disorders in French Family Practice.

PubMed

Norton, Joanna; Engberink, Agnès Oude; Gandubert, Catherine; Ritchie, Karen; Mann, Anthony; David, Michel; Capdevielle, Delphine

2017-08-01

Provide up-to-date detection rates for common mental disorders (CMD) and examine patient service-use since the Preferred Doctor scheme was introduced to France in 2005, with patients encouraged to register with and consult a family practitioner (FP) of their choice. Study of 1133 consecutive patients consulting 38 FPs in the Montpellier region, replicating a study performed before the scheme. Patients in the waiting room completed the self-report Patient Health Questionnaire (PHQ) and Client Service-Receipt Inventory with questions on registration with a Preferred Doctor and doctor-shopping. CMD was defined as reaching PHQ criteria for depression, somatoform, panic or anxiety disorder. For each patient, FPs completed a questionnaire capturing psychiatric caseness. 81.2% of patients were seeing their Preferred Doctor on the survey-day. Of those with a CMD, 52.6% were detected by the FP. This increased with CMD severity and comorbidity. Detected cases were more likely to be consulting their Preferred Doctor (84.7% versus 79.4% for non-detected cases, p = 0.05) rather than another FP. They declared more visits to psychiatrists (17.2% versus 6.7%, p = 0.002). There was no association with consultation frequency or doctor-shopping, which both declined between the two studies. The CMD detection rate is relatively high, with no increase compared to our previous study, despite a decline in doctor-shopping. An explanation is the same high proportion of patients visiting their usual FP on the survey-day at both periods, suggesting a limited impact of the scheme on care continuity. FP action taken highlights the importance of improving detection for providing care to patients with CMDs.

Health Service Utilisation, Detection Rates by Family Practitioners, and Management of Patients with Common Mental Disorders in French Family Practice

PubMed Central

Engberink, Agnès Oude; Gandubert, Catherine; Ritchie, Karen; Mann, Anthony; David, Michel; Capdevielle, Delphine

2017-01-01

Objective: Provide up-to-date detection rates for common mental disorders (CMD) and examine patient service-use since the Preferred Doctor scheme was introduced to France in 2005, with patients encouraged to register with and consult a family practitioner (FP) of their choice. Methods: Study of 1133 consecutive patients consulting 38 FPs in the Montpellier region, replicating a study performed before the scheme. Patients in the waiting room completed the self-report Patient Health Questionnaire (PHQ) and Client Service-Receipt Inventory with questions on registration with a Preferred Doctor and doctor-shopping. CMD was defined as reaching PHQ criteria for depression, somatoform, panic or anxiety disorder. For each patient, FPs completed a questionnaire capturing psychiatric caseness. Results: 81.2% of patients were seeing their Preferred Doctor on the survey-day. Of those with a CMD, 52.6% were detected by the FP. This increased with CMD severity and comorbidity. Detected cases were more likely to be consulting their Preferred Doctor (84.7% versus 79.4% for non-detected cases, p = 0.05) rather than another FP. They declared more visits to psychiatrists (17.2% versus 6.7%, p = 0.002). There was no association with consultation frequency or doctor-shopping, which both declined between the two studies. Conclusion: The CMD detection rate is relatively high, with no increase compared to our previous study, despite a decline in doctor-shopping. An explanation is the same high proportion of patients visiting their usual FP on the survey-day at both periods, suggesting a limited impact of the scheme on care continuity. FP action taken highlights the importance of improving detection for providing care to patients with CMDs. PMID:28107037

IP-FCM measures physiologic protein-protein interactions modulated by signal transduction and small-molecule drug inhibition.

PubMed

Smith, Stephen E P; Bida, Anya T; Davis, Tessa R; Sicotte, Hugues; Patterson, Steven E; Gil, Diana; Schrum, Adam G

2012-01-01

Protein-protein interactions (PPI) mediate the formation of intermolecular networks that control biological signaling. For this reason, PPIs are of outstanding interest in pharmacology, as they display high specificity and may represent a vast pool of potentially druggable targets. However, the study of physiologic PPIs can be limited by conventional assays that often have large sample requirements and relatively low sensitivity. Here, we build on a novel method, immunoprecipitation detected by flow cytometry (IP-FCM), to assess PPI modulation during either signal transduction or pharmacologic inhibition by two different classes of small-molecule compounds. First, we showed that IP-FCM can detect statistically significant differences in samples possessing a defined PPI change as low as 10%. This sensitivity allowed IP-FCM to detect a PPI that increases transiently during T cell signaling, the antigen-inducible interaction between ZAP70 and the T cell antigen receptor (TCR)/CD3 complex. In contrast, IP-FCM detected no ZAP70 recruitment when T cells were stimulated with antigen in the presence of the src-family kinase inhibitor, PP2. Further, we tested whether IP-FCM possessed sufficient sensitivity to detect the effect of a second, rare class of compounds called SMIPPI (small-molecule inhibitor of PPI). We found that the first-generation non-optimized SMIPPI, Ro-26-4550, inhibited the IL-2:CD25 interaction detected by IP-FCM. This inhibition was detectable using either a recombinant CD25-Fc chimera or physiologic full-length CD25 captured from T cell lysates. Thus, we demonstrate that IP-FCM is a sensitive tool for measuring physiologic PPIs that are modulated by signal transduction and pharmacologic inhibition.

Defined contribution: a part of our future.

PubMed Central

Baugh, Reginald F.

2003-01-01

Rising employer health care costs and consumer backlash against managed care are trends fostering the development of defined contribution plans. Defined contribution plans limit employer responsibility to a fixed financial contribution rather than a benefit program and dramatically increase consumer responsibility for health care decision making. Possible outcomes of widespread adoption of defined contribution plans are presented. PMID:12934869

Direct electron transfer of glucose oxidase-boron doped diamond interface: a new solution for a classical problem.

PubMed

Bai, Yan-Feng; Xu, Tai-Bin; Luong, John H T; Cui, Hui-Fang

2014-05-20

A planar boron-doped diamond (BDD) electrode was treated with KOH and functionalized with 3-aminopropyltriethoxysilane (APTES) to serve as a biosensing platform for biomolecule immobilization with glucose oxidase (GOx) as a test model. The free amino groups of GOx and APTES were cross-linked by glutaraldehyde (X), a bifunctional chemical to form a stable enzyme layer (GOx-X-APTES) on BDD. Micrographs obtained by scanning electron microscopy revealed that a mesoporous structure uniformly covered the BDD surface. Cyclic voltammetry of GOx immobilized showed a pair of well-defined redox peaks in neutral phosphate buffer solution, corresponding to the direct electron transfer of GOx. The apparent heterogeneous electron transfer rate constant of the immobilized GOx was estimated to be 8.85 ± 0.47 s(-1), considerably higher than the literature reported values. The determination of glucose was carried out by amperometry at -0.40 V, and the developed biosensor showed good reproducibility and stability with a detection limit of 20 μM. Both ascorbic and uric acids at normal physiological conditions did not provoke any signals. The dynamic range of glucose detection was further extended by covering the enzyme electrode with a thin Nafion layer. The Nafion/GOx-X-APTES/BDD biosensor showed excellent stability, a detection limit of 30 μM, a linear range between 35 μM and 8 mM, and a dynamic range up to 14 mM. Such analytical performances were compared favorably with other complicated sensing schemes using nanomaterials, redox polymers, and nanowires. The APTES-functionalized BDD could be easily extended to immobilize other redox enzymes or proteins of interests.

Predicting subtle behavioral responses of invertebrates to soil contaminants

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

Donkin, S.G.

1995-12-31

At concentration levels well below those which cause death and injury to soil invertebrates, a toxic chemical plume may yet effectively damage a soil ecosystem by triggering avoidance behavior among sensitive invertebrates as they move along the concentration gradient. The result may be a soil ecosystem lacking the benefits of effective nutrient cycling and mineralization which a thriving invertebrate population provides. While determining actual detection limits of invertebrates for chemical gradients in soils is experimentally difficult, theoretical calculations have suggested that such limits may be extremely low, and hence many organisms may sense and avoid concentrations of chemicals far belowmore » levels commonly considered acceptable. The minimum gradient (G) that can be detected by a receptor depends on the receptor radius (R), the chemical concentration (C), the diffusion constant of the chemical (D), the velocity of the organism (v), and the time over which the receptor integrates the chemical signal (t). In addition, the characteristics of that gradient are determined by interactions between the chemical and the soil particles (sorption/desorption), and advection through the pore spaces. The example of lead (Pb), a neurotoxic metal with demonstrated behavioral effects on the free-living nematode Caenorhabditis elegans, is used to model a chemical migrating through a soil. Based on experimentally determined Pb concentrations which elicited avoidance behavior in nematodes, and sorption characteristics of defined Pb-soil systems, the minimum detectable gradient (G) produced by a solubilized Pb plume in several soils was modeled. The results predict maximum allowable Pb levels in a soil if a healthy invertebrate community is desired, and suggest areas for further research into the subtle behavioral effects of environmental toxicants ore sensitive invertebrates.« less

A practical approach to determination of laboratory GC-MS limits of detection.

PubMed

Underwood, P J; Kananen, G E; Armitage, E K

1997-01-01

Determination of limit of detection (LOD) values in a forensic laboratory serves a fundamental forensic requirement for assay performance. In addition to demonstrating assay capability, LOD values can also be used to fulfill certification requirements of a high-volume forensic drug laboratory. The LOD was defined as the lowest concentration of drug that the laboratory can detect in a specimen with forensic certainty at a minimum of 85% of the time. Overall batch acceptance criteria included acceptable quantitation of control materials (within 20% of target), acceptable chromatography (symmetry, peak integration, peak shape, peak, and baseline resolution), retention time within +/-1% of the extracted standard, and mass ion ratios within +/-20% of the extracted standard mass ion ratios. Individual specimen acceptance criteria were the same as the batch acceptance criteria excluding the quantitation requirement. Data were collected from all instruments on different runs. A minimum of ten data points was required for each certified instrument, and a minimum of 85% of data points was acceptable. Quantitation within +/-20% of the LOD concentration was not required, but acceptable mass ratios were required. Data points with poor chromatography (internal standard failed mass ratios; interference of the baseline, for example, shoulders; asymmetry; and baseline resolution) was omitted from the acceptable rate calculation. Data points with good chromatography with failed mass ion ratios were included in the acceptable rate calculation. With these criteria, we established the following LODs: 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid, 2 ng/mL; benzoylecgonine, 5 ng/mL; phencyclidine, 2.5 ng/mL; amphetamine, 150 ng/mL; methamphetamine, 100 ng/mL; codeine, 500 ng/mL; and morphine, 1000 ng/mL.

Thermal background noise limitations

NASA Technical Reports Server (NTRS)

Gulkis, S.

1982-01-01

Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

H.E.S.S. discovery of VHE γ-rays from the quasar PKS 1510-089

NASA Astrophysics Data System (ADS)

H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balenderan, S.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker Tjus, J.; Behera, B.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Chaves, R. C. G.; Cheesebrough, A.; Colafrancesco, S.; Cologna, G.; Conrad, J.; Couturier, C.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; deWilt, P.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; O'C. Drury, L.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fernandez, D.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Gast, H.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Göring, D.; Grondin, M.-H.; Grudzińska, M.; Häffner, S.; Hague, J. D.; Hahn, J.; Hampf, D.; Harris, J.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Khélifi, B.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lefaucheur, J.; Lemoine-Goumard, M.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, G.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Menzler, U.; Moderski, R.; Mohamed, M.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nguyen, N.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Parsons, R. D.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Raue, M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Trichard, C.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Wouters, D.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H. S.

2013-06-01

The quasar PKS 1510-089 (z = 0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in the optical and GeV bands, to search for very high energy (VHE, defined as E ≥ 0.1 TeV) emission. VHE γ-rays were detected with a statistical significance of 9.2 standard deviations in 15.8 h of H.E.S.S. data taken during March and April 2009. A VHE integral flux of I(0.15 TeV < E < 1.0 TeV)= (1.0 ± 0.2stat ± 0.2sys) × 10-11 cm-2 s-1 is measured. The best-fit power law to the VHE data has a photon index of Γ = 5.4 ± 0.7stat ± 0.3sys. The GeV and optical light curves show pronounced variability during the period of H.E.S.S. observations. However, there is insufficient evidence to claim statistically significant variability in the VHE data. Because of its relatively high redshift, the VHE flux from PKS 1510-089 should suffer considerable attenuation in the intergalactic space due to the extragalactic background light (EBL). Hence, the measured γ-ray spectrum is used to derive upper limits on the opacity due to EBL, which are found to be comparable with the previously derived limits from relatively-nearby BL Lac objects. Unlike typical VHE-detected blazars where the broadband spectrum is dominated by nonthermal radiation at all wavelengths, the quasar PKS 1510-089 has a bright thermal component in the optical to UV frequency band. Among all VHE detected blazars, PKS 1510-089 has the most luminous broad line region. The detection of VHE emission from this quasar indicates a low level of γ - γ absorption on the internal optical to UV photon field.

Analysis of hepatitis C NS5A resistance associated polymorphisms using ultra deep single molecule real time (SMRT) sequencing.

PubMed

Bergfors, Assar; Leenheer, Daniël; Bergqvist, Anders; Ameur, Adam; Lennerstrand, Johan

2016-02-01

Development of Hepatitis C virus (HCV) resistance against direct-acting antivirals (DAAs), including NS5A inhibitors, is an obstacle to successful treatment of HCV when DAAs are used in sub-optimal combinations. Furthermore, it has been shown that baseline (pre-existing) resistance against DAAs is present in treatment naïve-patients and this will potentially complicate future treatment strategies in different HCV genotypes (GTs). Thus the aim was to detect low levels of NS5A resistant associated variants (RAVs) in a limited sample set of treatment-naïve patients of HCV GT1a and 3a, since such polymorphisms can display in vitro resistance as high as 60000 fold. Ultra-deep single molecule real time (SMRT) sequencing with the Pacific Biosciences (PacBio) RSII instrument was used to detect these RAVs. The SMRT sequencing was conducted on ten samples; three of them positive with Sanger sequencing (GT1a Q30H and Y93N, and GT3a Y93H), five GT1a samples, and two GT3a non-positive samples. The same methods were applied to the HCV GT1a H77-plasmid in a dilution series, in order to determine the error rates of replication, which in turn was used to determine the limit of detection (LOD), as defined by mean + 3SD, of minority variants down to 0.24%. We found important baseline NS5A RAVs at levels between 0.24 and 0.5%, which could potentially have clinical relevance. This new method with low level detection of baseline RAVs could be useful in predicting the most cost-efficient combination of DAA treatment, and reduce the treatment duration for an HCV infected individual. Copyright © 2015 Elsevier B.V. All rights reserved.

Exposure to carcinogens for defined job categories in Norway's offshore petroleum industry, 1970 to 2005

PubMed Central

Steinsvåg, Kjersti; Bråtveit, Magne; Moen, Bente E

2007-01-01

Objectives To identify and describe the exposure to selected known and suspected carcinogenic agents, mixtures and exposure circumstances for defined job categories in Norway's offshore petroleum industry from 1970 to 2005, in order to provide exposure information for a planned cohort study on cancer. Methods Background information on possible exposure was obtained through company visits, including interviewing key personnel (n = 83) and collecting monitoring reports (n = 118) and other relevant documents (n = 329). On the basis of a previous questionnaire administered to present and former offshore employees in 1998, 27 job categories were defined. Results This study indicated possible exposure to 18 known and suspected carcinogenic agents, mixtures or exposure circumstances. Monitoring reports were obtained on seven agents (benzene, mineral oil mist and vapour, respirable and total dust, asbestos fibres, refractory ceramic fibres, formaldehyde and tetrachloroethylene). The mean exposure level of 367 personal samples of benzene was 0.037 ppm (range: less than the limit of detection to 2.6 ppm). Asbestos fibres were detected (0.03 fibres/cm3) when asbestos‐containing brake bands were used in drilling draw work in 1988. Personal samples of formaldehyde in the process area ranged from 0.06 to 0.29 mg/m3. Descriptions of products containing known and suspected carcinogens, exposure sources and processes were extracted from the collected documentation and the interviews of key personnel. Conclusions This study described exposure to 18 known and suspected carcinogenic agents, mixtures and exposure circumstances for 27 job categories in Norway's offshore petroleum industry. For a planned cohort study on cancer, quantitative estimates of exposure to benzene, and mineral oil mist and vapour might be developed. For the other agents, information in the present study can be used for further assessment of exposure, for instance, by expert judgement. More systematic exposure surveillance is needed in this industry. For future studies, new monitoring programmes need to be implemented. PMID:17043075

Exposure to carcinogens for defined job categories in Norway's offshore petroleum industry, 1970 to 2005.

PubMed

Steinsvåg, Kjersti; Bråtveit, Magne; Moen, Bente E

2007-04-01

To identify and describe the exposure to selected known and suspected carcinogenic agents, mixtures and exposure circumstances for defined job categories in Norway's offshore petroleum industry from 1970 to 2005, in order to provide exposure information for a planned cohort study on cancer. Background information on possible exposure was obtained through company visits, including interviewing key personnel (n = 83) and collecting monitoring reports (n = 118) and other relevant documents (n = 329). On the basis of a previous questionnaire administered to present and former offshore employees in 1998, 27 job categories were defined. This study indicated possible exposure to 18 known and suspected carcinogenic agents, mixtures or exposure circumstances. Monitoring reports were obtained on seven agents (benzene, mineral oil mist and vapour, respirable and total dust, asbestos fibres, refractory ceramic fibres, formaldehyde and tetrachloroethylene). The mean exposure level of 367 personal samples of benzene was 0.037 ppm (range: less than the limit of detection to 2.6 ppm). Asbestos fibres were detected (0.03 fibres/cm3) when asbestos-containing brake bands were used in drilling draw work in 1988. Personal samples of formaldehyde in the process area ranged from 0.06 to 0.29 mg/m3. Descriptions of products containing known and suspected carcinogens, exposure sources and processes were extracted from the collected documentation and the interviews of key personnel. This study described exposure to 18 known and suspected carcinogenic agents, mixtures and exposure circumstances for 27 job categories in Norway's offshore petroleum industry. For a planned cohort study on cancer, quantitative estimates of exposure to benzene, and mineral oil mist and vapour might be developed. For the other agents, information in the present study can be used for further assessment of exposure, for instance, by expert judgement. More systematic exposure surveillance is needed in this industry. For future studies, new monitoring programmes need to be implemented.

Statistical process control and verifying positional accuracy of a cobra motion couch using step-wedge quality assurance tool.

PubMed

Binny, Diana; Lancaster, Craig M; Trapp, Jamie V; Crowe, Scott B

2017-09-01

This study utilizes process control techniques to identify action limits for TomoTherapy couch positioning quality assurance tests. A test was introduced to monitor accuracy of the applied couch offset detection in the TomoTherapy Hi-Art treatment system using the TQA "Step-Wedge Helical" module and MVCT detector. Individual X-charts, process capability (cp), probability (P), and acceptability (cpk) indices were used to monitor a 4-year couch IEC offset data to detect systematic and random errors in the couch positional accuracy for different action levels. Process capability tests were also performed on the retrospective data to define tolerances based on user-specified levels. A second study was carried out whereby physical couch offsets were applied using the TQA module and the MVCT detector was used to detect the observed variations. Random and systematic variations were observed for the SPC-based upper and lower control limits, and investigations were carried out to maintain the ongoing stability of the process for a 4-year and a three-monthly period. Local trend analysis showed mean variations up to ±0.5 mm in the three-monthly analysis period for all IEC offset measurements. Variations were also observed in the detected versus applied offsets using the MVCT detector in the second study largely in the vertical direction, and actions were taken to remediate this error. Based on the results, it was recommended that imaging shifts in each coordinate direction be only applied after assessing the machine for applied versus detected test results using the step helical module. User-specified tolerance levels of at least ±2 mm were recommended for a test frequency of once every 3 months to improve couch positional accuracy. SPC enables detection of systematic variations prior to reaching machine tolerance levels. Couch encoding system recalibrations reduced variations to user-specified levels and a monitoring period of 3 months using SPC facilitated in detecting systematic and random variations. SPC analysis for couch positional accuracy enabled greater control in the identification of errors, thereby increasing confidence levels in daily treatment setups. © 2017 Royal Brisbane and Women's Hospital, Metro North Hospital and Health Service. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

STATISTICAL METHODS FOR ENVIRONMENTAL APPLICATIONS USING DATA SETS WITH BELOW DETECTION LIMIT OBSERVATIONS AS INCORPORTED IN PROUCL 4.0

EPA Science Inventory

Nondetect (ND) or below detection limit (BDL) results cannot be measured accurately, and, therefore, are reported as less than certain detection limit (DL) values. However, since the presence of some contaminants (e.g., dioxin) in environmental media may pose a threat to human he...

Reactive case detection for malaria elimination: real-life experience from an ongoing program in Swaziland.

PubMed

Sturrock, Hugh J W; Novotny, Joe M; Kunene, Simon; Dlamini, Sabelo; Zulu, Zulisile; Cohen, Justin M; Hsiang, Michelle S; Greenhouse, Bryan; Gosling, Roly D

2013-01-01

As countries move towards malaria elimination, methods to identify infections among populations who do not seek treatment are required. Reactive case detection, whereby individuals living in close proximity to passively detected cases are screened and treated, is one approach being used by a number of countries including Swaziland. An outstanding issue is establishing the epidemiologically and operationally optimal screening radius around each passively detected index case. Using data collected between December 2009 and June 2012 from reactive case detection (RACD) activities in Swaziland, we evaluated the effect of screening radius and other risk factors on the probability of detecting cases by reactive case detection. Using satellite imagery, we also evaluated the household coverage achieved during reactive case detection. Over the study period, 250 cases triggered RACD, which identified a further 74 cases, showing the value of RACD over passive surveillance alone. Results suggest that the odds of detecting a case within the household of the index case were significantly higher than in neighbouring households (odds ratio (OR) 13, 95% CI 3.1-54.4). Furthermore, cases were more likely to be detected when RACD was conducted within a week of the index presenting at a health facility (OR 8.7, 95% CI 1.1-66.4) and if the index household had not been sprayed with insecticide (OR sprayed vs not sprayed 0.11, 95% CI 0.03-0.46). The large number of households missed during RACD indicates that a 1 km screening radius may be impractical in such resource limited settings such as Swaziland. Future RACD in Swaziland could be made more effective by achieving high coverage amongst individuals located near to index cases and in areas where spraying has not been conducted. As well as allowing the programme to implement RACD more rapidly, this would help to more precisely define the optimal screening radius.

Comparison of kinematic and dynamic leg trajectory optimization techniques for biped robot locomotion

NASA Astrophysics Data System (ADS)

Khusainov, R.; Klimchik, A.; Magid, E.

2017-01-01

The paper presents comparison analysis of two approaches in defining leg trajectories for biped locomotion. The first one operates only with kinematic limitations of leg joints and finds the maximum possible locomotion speed for given limits. The second approach defines leg trajectories from the dynamic stability point of view and utilizes ZMP criteria. We show that two methods give different trajectories and demonstrate that trajectories based on pure dynamic optimization cannot be realized due to joint limits. Kinematic optimization provides unstable solution which can be balanced by upper body movement.

Report for Batch Leach Analyses on Sediments at 100-HR-3 Operable Unit, Boreholes C7620, C7621, C7622, C7623, C7626, C7627, C7628, C7629, C7630, and C7866. Revision 1.

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

Lindberg, Michael J.

2012-04-25

This is a revision to a previously released report. This revision contains additional analytical results for the sample with HEIS number B2H4X7. Between November 4, 2010 and October 26, 2011 sediment samples were received from 100-HR-3 Operable Unit for geochemical studies. The analyses for this project were performed at the 331 building located in the 300 Area of the Hanford Site. The analyses were performed according to Pacific Northwest National Laboratory (PNNL) approved procedures and/or nationally recognized test procedures. The data sets include the sample identification numbers, analytical results, estimated quantification limits (EQL), and quality control data. The preparatory andmore » analytical quality control requirements, calibration requirements, acceptance criteria, and failure actions are defined in the on-line QA plan 'Conducting Analytical Work in Support of Regulatory Programs' (CAW). This QA plan implements the Hanford Analytical Services Quality Assurance Requirements Documents (HASQARD) for PNNL. Samples were received with a chain of custody (COC) and were analyzed according to the sample identification numbers supplied by the client. All Samples were refrigerated upon receipt until prepared for analysis. All samples were received with custody seals intact unless noted in the Case Narrative. Holding time is defined as the time from sample preparation to the time of analyses. The prescribed holding times were met for all analytes unless noted in the Case Narrative. All reported analytical results meet the requirements of the CAW or client specified SOW unless noted in the case narrative. Due to the requirements of the statement of work and sampling events in the field, the 28 day and the 48 hr requirements cannot be met. The statement of work requires samples to be selected at the completion of the borehole. It is not always possible to complete a borehole and have the samples shipped to the laboratory within the hold time requirements. Duplicate RPD for Uranium 238 (38.9%) was above the acceptance limit (35) in 1E05003-DUP1 for ICPMS-Tc-U-WE The sample result is less than 10 times the detection limits. Duplicate recoveries are not applicable to this analyte. Duplicate RPD for Silver 107 (68.2%) was above the acceptance limit (35) in 2C06004-DUP1 for ICPMS-RCRA-AE The sample result is less than 10 times the detection limits. Duplicate recoveries are not applicable to this analyte. Matrix Spike Recovery for Chromium, Hexavalent (48.8%) was outside acceptance limits (75-125) in 1E23001-MS1 for Hexavalent Chromium/Soil. Potential Matrix interference. Sample results associated with this batch are below the EQL. There should be no impact to the data as reported. Matrix Spike Recovery for Chromium, Hexavalent (50.2%) was outside acceptance limits (75-125) in 2B22010-MS1 for Hexavalent Chromium/Soil. Potential Matrix interference. Sample results associated with this batch are below the EQL. There should be no impact to the data as reported.« less

Non-targeted, high resolution mass spectrometry strategy for simultaneous monitoring of xenobiotics and endogenous compounds in green sea turtles on the Great Barrier Reef.

PubMed

Heffernan, Amy L; Gómez-Ramos, Maria M; Gaus, Caroline; Vijayasarathy, Soumini; Bell, Ian; Hof, Christine; Mueller, Jochen F; Gómez-Ramos, Maria J

2017-12-01

Chemical contamination poses a threat to ecosystem, biota and human health, and identifying these hazards is a complex challenge. Traditional hazard identification relies on a priori-defined targets of limited chemical scope, and is generally inappropriate for exploratory studies such as explaining toxicological effects in environmental systems. Here we present a non-target high resolution mass spectrometry environmental monitoring study with multivariate statistical analysis to simultaneously detect biomarkers of exposure (e.g. xenobiotics) and biomarkers of effect in whole turtle blood. Borrowing the concept from clinical chemistry, a case-control sampling approach was used to investigate the potential influence of xenobiotics of anthropogenic origin on free-ranging green sea turtles (Chelonia mydas) from a remote, offshore 'control' site; and two coastal 'case' sites influenced by urban/industrial and agricultural activities, respectively, on the Great Barrier Reef in North Queensland, Australia. Multiple biomarkers of exposure, including sulfonic acids (n=9), a carbamate insecticide metabolite, and other industrial chemicals; and five biomarkers of effect (lipid peroxidation products), were detected in case sites. Additionally, two endogenous biomarkers of neuroinflammation and oxidative stress were identified, and showed moderate-to-strong correlations with clinical measures of inflammation and liver dysfunction. Our data filtering strategy overcomes limitations of traditional a priori selection of target compounds, and adds to the limited environmental xenobiotic metabolomics literature. To our knowledge this is the first case-control study of xenobiotics in marine megafauna, and demonstrates the utility of green sea turtles to link internal and external exposure, to explain potential toxicological effects in environmental systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Universal EUV in-band intensity detector

DOEpatents

Berger, Kurt W.

2004-08-24

Extreme ultraviolet light is detected using a universal in-band detector for detecting extreme ultraviolet radiation that includes: (a) an EUV sensitive photodiode having a diode active area that generates a current responsive to EUV radiation; (b) one or more mirrors that reflects EUV radiation having a defined wavelength(s) to the diode active area; and (c) a mask defining a pinhole that is positioned above the diode active area, wherein EUV radiation passing through the pinhole is restricted substantially to illuminating the diode active area.

Influence of slope on fire spread rate

Treesearch

B.W. Butler; W.R. Anderson; E.A. Catchpole

2007-01-01

Data demonstrate the effect of slope on heading and backing fires burning through woody fuels. The data indicate that the upper limit of heading fire rate of spread is defined by the rate of spread up a vertical fuel array, and the lower limit is defined by the rate of spread of a backing fire burning downslope. The minimum spread rate is found to occur at nominally --...

Epidemiologic Evaluation of Measurement Data in the Presence of Detection Limits

PubMed Central

Lubin, Jay H.; Colt, Joanne S.; Camann, David; Davis, Scott; Cerhan, James R.; Severson, Richard K.; Bernstein, Leslie; Hartge, Patricia

2004-01-01

Quantitative measurements of environmental factors greatly improve the quality of epidemiologic studies but can pose challenges because of the presence of upper or lower detection limits or interfering compounds, which do not allow for precise measured values. We consider the regression of an environmental measurement (dependent variable) on several covariates (independent variables). Various strategies are commonly employed to impute values for interval-measured data, including assignment of one-half the detection limit to nondetected values or of “fill-in” values randomly selected from an appropriate distribution. On the basis of a limited simulation study, we found that the former approach can be biased unless the percentage of measurements below detection limits is small (5–10%). The fill-in approach generally produces unbiased parameter estimates but may produce biased variance estimates and thereby distort inference when 30% or more of the data are below detection limits. Truncated data methods (e.g., Tobit regression) and multiple imputation offer two unbiased approaches for analyzing measurement data with detection limits. If interest resides solely on regression parameters, then Tobit regression can be used. If individualized values for measurements below detection limits are needed for additional analysis, such as relative risk regression or graphical display, then multiple imputation produces unbiased estimates and nominal confidence intervals unless the proportion of missing data is extreme. We illustrate various approaches using measurements of pesticide residues in carpet dust in control subjects from a case–control study of non-Hodgkin lymphoma. PMID:15579415

Non-enzymatic detection of glucose using poly(azure A)-nickel modified glassy carbon electrode.

PubMed

Liu, Tong; Luo, Yiqun; Zhu, Jiaming; Kong, Liyan; Wang, Wen; Tan, Liang

2016-08-15

A simple, sensitive and selective non-enzymatic glucose sensor was constructed in this paper. The poly(azure A)-nickel modified glassy carbon electrode was successfully fabricated by the electropolymerization of azure A and the adsorption of Ni(2+). The Ni modified electrode, which was characterized by scanning electron microscope, cyclic voltammetry, electrochemical impedance spectra and X-ray photoelectron spectroscopy measurements, respectively, displayed well-defined current responses of the Ni(III)/Ni(II) couple and showed a good activity for electrocatalytic oxidation of glucose in alkaline medium. Under the optimized conditions, the developed sensor exhibited a broad linear calibration range of 5 μM-12mM for quantification of glucose and a low detection limit of 0.64μM (3σ). The excellent analytical performance including simple structure, fast response time, good anti-interference ability, satisfying stability and reliable reproducibility were also found from the proposed amperometric sensor. The results were satisfactory for the determination of glucose in human serum samples as comparison to those from a local hospital. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of sulfur in kerosene by combustion and molecular absorption spectrometry in the gas phase

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

Ruschak, M.L.; Syty, A.

1982-08-01

A technique of nonflame molecular adsorption in the gas phase developed for the determination of sulfite trapped in tetrachloromercurate, is described herein for application to the determination of total sulfur in kerosene. The burner head is removed from the atomic absorption spectrometer and replaced with a flow-through absorption cell. A special reaction vessel is used to evolve SO/sub 2/ from the sulfite in a precise and convenient manner. The transient absorbance caused by the SO/sub 2/, as it is carried through the absorption cell, is measured. Both spiked and unspiked samples of kerosene were analyzed, and the reproducibility of themore » repeated runs is evidenced by a relative standard deviation from the mean of 5% for the unspiked kerosene and 4% for the spiked kerosene. If the detection level is defined as that concentration of S which gives a % S twice the standard deviation from the mean yields, the detection limit for the present method is 0.002% S by weight in kerosene.« less

Quantifying the relationship between sequence and three-dimensional structure conservation in RNA

PubMed Central

2010-01-01

Background In recent years, the number of available RNA structures has rapidly grown reflecting the increased interest on RNA biology. Similarly to the studies carried out two decades ago for proteins, which gave the fundamental grounds for developing comparative protein structure prediction methods, we are now able to quantify the relationship between sequence and structure conservation in RNA. Results Here we introduce an all-against-all sequence- and three-dimensional (3D) structure-based comparison of a representative set of RNA structures, which have allowed us to quantitatively confirm that: (i) there is a measurable relationship between sequence and structure conservation that weakens for alignments resulting in below 60% sequence identity, (ii) evolution tends to conserve more RNA structure than sequence, and (iii) there is a twilight zone for RNA homology detection. Discussion The computational analysis here presented quantitatively describes the relationship between sequence and structure for RNA molecules and defines a twilight zone region for detecting RNA homology. Our work could represent the theoretical basis and limitations for future developments in comparative RNA 3D structure prediction. PMID:20550657

Integrating Machine Learning into Space Operations

NASA Astrophysics Data System (ADS)

Kelly, K. G.

There are significant challenges with managing activities in space, which for the scope of this paper are primarily the identification of objects in orbit, maintaining accurate estimates of the orbits of those objects, detecting changes to those orbits, warning of possible collisions between objects and detection of anomalous behavior. The challenges come from the large amounts of data to be processed, which is often incomplete and noisy, limitations on the ability to influence objects in space and the overall strategic importance of space to national interests. The focus of this paper is on defining an approach to leverage the improved capabilities that are possible using state of the art machine learning in a way that empowers operations personnel without sacrificing the security and mission assurance associated with manual operations performed by trained personnel. There has been significant research in the development of algorithms and techniques for applying machine learning in this domain, but deploying new techniques into such a mission critical domain is difficult and time consuming. Establishing a common framework could improve the efficiency with which new techniques are integrated into operations and the overall effectiveness at providing improvements.

Signatures of mountain building: Detrital zircon U/Pb ages from northeast Tibet

USGS Publications Warehouse

Lease, Richard O.; Burbank, Douglas W.; Gehrels, George E.; Wang, Zhicai; Yuan, Daoyang

2007-01-01

Although detrital zircon has proven to be a powerful tool for determining provenance, past work has focused primarily on delimiting regional source terranes. Here we explore the limits of spatial resolution and stratigraphic sensitivity of detrital zircon in ascertaining provenance, and we demonstrate its ability to detect source changes for terranes separated by only a few tens of kilometers. For such an analysis to succeed for a given mountain, discrete intrarange source terranes must have unique U/Pb zircon age signatures and sediments eroded from the range must have well-defined depositional ages. Here we use ∼1400 single-grain U/Pb zircon ages from northeastern Tibet to identify and analyze an area that satisfies these conditions. This analysis shows that the edges of intermontane basins are stratigraphically sensitive to discrete, punctuated changes in local source terranes. By tracking eroding rock units chronologically through the stratigraphic record, this sensitivity permits the detection of the differential rock uplift and progressive erosion that began ca. 8 Ma in the Laji Shan, a 10-25-km-wide range in northeastern Tibet with a unique U/Pb age signature.

SOME GEOCHEMICAL METHODS OF URANIUM EXPLORATION

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

Illsley, C.T.; Bills, C.W.; Pollock, J.W.

Geochemical research and development projects were carried on to provide basic information which may be applied to exploration or general studies of uranium geology. The applications and limitations of various aspects of geochemistry to uranium geological problems are considerd. Modifications of existing analytical techniques were made and tested in the laboratory and in the field. These include rapid quantitative determination of unranium in water, soil and peat, and of trace amounts of sulfate and phosphate in water. Geochemical anomaly'' has been defined as a significant departure from the average abundance background of an element where the distribution has not beenmore » disturbed by mineralization. The detection and significance of geocthemical anomalies are directly related to the mobility of the element being sought in the zone of weathering. Mobility of uranium is governed by complex physical, chemical, and biological factors. For uranium anomalies in surface materils, the chemicaly factors affecting mobility are the most sigificant. The effects of pH, solubility, coprecipitution, adsorption complexion, or compound formation are discussed in relation to anomalies detected in water, soil, and stream sediments. (auth)« less

Strategies for automatic processing of large aftershock sequences

NASA Astrophysics Data System (ADS)

Kvaerna, T.; Gibbons, S. J.

2017-12-01

Aftershock sequences following major earthquakes present great challenges to seismic bulletin generation. The analyst resources needed to locate events increase with increased event numbers as the quality of underlying, fully automatic, event lists deteriorates. While current pipelines, designed a generation ago, are usually limited to single passes over the raw data, modern systems also allow multiple passes. Processing the raw data from each station currently generates parametric data streams that are later subject to phase-association algorithms which form event hypotheses. We consider a major earthquake scenario and propose to define a region of likely aftershock activity in which we will detect and accurately locate events using a separate, specially targeted, semi-automatic process. This effort may use either pattern detectors or more general algorithms that cover wider source regions without requiring waveform similarity. An iterative procedure to generate automatic bulletins would incorporate all the aftershock event hypotheses generated by the auxiliary process, and filter all phases from these events from the original detection lists prior to a new iteration of the global phase-association algorithm.

An electrochemiluminescent biosensor for glucose based on the electrochemiluminescence of luminol on the nafion/glucose oxidase/poly(nickel(II)tetrasulfophthalocyanine)/multi-walled carbon nanotubes modified electrode.

PubMed

Qiu, Bin; Lin, Zhenyu; Wang, Jian; Chen, Zhihuang; Chen, Jinhua; Chen, Guonan

2009-04-15

A poly(nickel(II) tetrasulfophthalocyanine)/multi-walled carbon nanotubes composite modified electrode (polyNiTSPc/MWNTs) was fabricated by electropolymerization of NiTSPc on MWNTs-modified glassy carbon electrode (GCE). The modified electrode was found to be able to greatly improve the emission of luminol electrochemiluminescence (ECL) in a solution containing hydrogen peroxide. Glucose oxidase (GOD) was immobilized on the surface of polyNiTSPc/MWNTs modified GC electrode by Nafion to establish an ECL glucose sensor. Under the optimum conditions, the linear response range of glucose was 1.0x10(-6) to 1.0x10(-4) mol L(-1) with a detection limit of 8.0x10(-8) mol L(-1) (defined as the concentration that could be detected at the signal-to-noise ratio of 3). The ECL sensor showed an outstanding well reproducibility and long-term stability. The established method has been applied to determine the glucose concentrations in real serum samples with satisfactory results.

Determination of the hormonal growth promoter 17alpha-methyltestosterone in food-producing animals: bovine hair analysis by HPLC-MS/MS.

PubMed

Regal, P; Nebot, C; Vázquez, B I; Cepeda, A; Fente, C A

2010-01-01

This paper describes the development, validation and application of a confirmatory method to detect 17alpha-methyltestosterone (MT) in bovine hair, to aid in controlling the administration of this growth promoter in meat-producing animals. After cryogenic grinding, MT was removed from the hair matrix using a single step extraction procedure with acetonitrile. Hydroxylamine derivatisation was used to enhance analyte determination with an electrospray ionisation (ESI) source. Determination was carried out using a triple quadrupole liquid chromatography tandem mass spectrometer (LC-MS/MS) in multiple reaction monitoring mode (MRM). The method was validated in accordance with the criteria defined in Commission Decision 2002/657/EC and using deuterated testosterone (T-d(3)) as the internal standard. The decision limit (CCalpha) was 0.07 ng g(-1) and the detection capability (CCbeta) was 0.12 ng g(-1). Repeatability was CV% (7%), within-laboratory reproducibility was CV% (11.0%), and trueness was (87%). Applicability of the method was demonstrated in an animal study. Samples obtained from animal experiments were analyzed and the presence of MT was confirmed.

Validation of AN Hplc-Dad Method for the Classification of Green Teas

NASA Astrophysics Data System (ADS)

Yu, Jingbo; Ye, Nengsheng; Gu, Xuexin; Liu, Ni

A reversed phase high performance liquid chromatography (RP-HPLC) separation coupled with diode array detection (DAD) and electrospray ionization mass spectrometer (ESI/MS) was developed and optimized for the classification of green teas. Five catechins [epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechin (EC), gallocatechin gallate (GCG), epicatechin gallate (ECG)] had been identified and quantified by the HPLC-DAD-ESI/MS/MS method. The limit of detection (LOD) of five catechins was within the range of 1.25-15 ng. All the analytes exhibited good linearity up to 2500 ng. These compounds were considered as chemical descriptors to define groups of green teas. Chemometric methods including principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied for the purpose. Twelve green tea samples originating from different regions were subjected to reveal the natural groups. The results showed that the analyzed green teas were differentiated mainly by provenance; HCA afforded an excellent performance in terms of recognition and prediction abilities. This method was accurate and reproducible, providing a potential approach for authentication of green teas.

Indocyanine green detects sentinel lymph nodes in early breast cancer.

PubMed

Liu, Jun; Huang, Linping; Wang, Ning; Chen, Ping

2017-04-01

Objective To explore the clinical value of indocyanine green (ICG) for the fluorescence-guided detection of sentinel lymph nodes (SLNs) during sentinel lymph node biopsy (SLNB) in patients with early breast cancer. Methods This retrospective study included female patients with breast cancer. Patients were administered methylene blue and ICG using standard techniques. All SLNs that were collected during surgery were submitted for pathological examination. SLNs were defined as those that were either fluorescent, blue, fluorescent and blue or palpably suspicious. Surgical complications, axillary recurrence, distant metastasis and overall survival rates were observed postoperatively. Results A total of 60 patients were enrolled in the study. The fluorescence detection rate of SLNs was 100% ( n = 177), with a mean of 2.95 SLNs per patient. The methylene blue staining rate was 88.3% ( n = 106), with a mean of 1.77 SLNs per patient. Pathological assessment of intraoperative frozen specimens revealed SLN metastases in 10 patients, who immediately underwent axillary lymph node dissection. No patient had axillary recurrence or distant metastases, with a survival rate of 100%. Patients who underwent SLNB showed good appearance in the axillary wound, with no limited shoulder joint abduction and upper limb oedema. Conclusion Fluorescence-guided SLNB has several advantages and is suitable for clinical application.

Real-time redox speciation of iron in estuarine and coastal surface waters.

PubMed

Huang, Yongming; Yuan, Dongxing; Zhu, Yong; Feng, Sichao

2015-03-17

An automated, shipboard-use system was developed for real-time speciation of iron in coastal surface waters. It comprised a towed Fish underway sampler and a modified reverse flow injection analysis system with a liquid waveguide capillary flow cell-spectrophotometric detection device. The detection was based on the reaction between ferrozine and Fe(II). The detection limits of 0.3 and 0.7 nM were achieved for Fe(II) and Fe(II+III), together with their respective dynamic linear ranges of 0.5-250 and 0.9-250 nM. The system was successfully deployed and run consecutively for about 1 week during a cruise in August 2009 to the East China Sea off the Changjiang Estuary. The distribution of operationally defined field dissolvable Fe(II) and Fe(II+III) (expressed as Fea(II) and Fea(II+III)) in these areas was obtained, which showed that both Fea(II) and Fea(II+III) concentrations decreased with salinity when there were relatively high Fea(II) concentrations (up to about 120 nM) near shore. A distinct distribution of Fea(II) to Fea(II+III) ratios was also revealed, with a ratio of 0.58 in the water off Changjiang Estuary and 0.19 in the open ocean.

Mapping gullies, dunes, lava fields, and landslides via surface roughness

NASA Astrophysics Data System (ADS)

Korzeniowska, Karolina; Pfeifer, Norbert; Landtwing, Stephan

2018-01-01

Gully erosion is a widespread and significant process involved in soil and land degradation. Mapping gullies helps to quantify past, and anticipate future, soil losses. Digital terrain models offer promising data for automatically detecting and mapping gullies especially in vegetated areas, although methods vary widely measures of local terrain roughness are the most varied and debated among these methods. Rarely do studies test the performance of roughness metrics for mapping gullies, limiting their applicability to small training areas. To this end, we systematically explored how local terrain roughness derived from high-resolution Light Detection And Ranging (LiDAR) data can aid in the unsupervised detection of gullies over a large area. We also tested expanding this method for other landforms diagnostic of similarly abrupt land-surface changes, including lava fields, dunes, and landslides, as well as investigating the influence of different roughness thresholds, resolutions of kernels, and input data resolution, and comparing our method with previously published roughness algorithms. Our results show that total curvature is a suitable metric for recognising analysed gullies and lava fields from LiDAR data, with comparable success to that of more sophisticated roughness metrics. Tested dunes or landslides remain difficult to distinguish from the surrounding landscape, partly because they are not easily defined in terms of their topographic signature.

Odour-causing compounds in air samples: gas-liquid partition coefficients and determination using solid-phase microextraction and GC with mass spectrometric detection.

PubMed

Godayol, Anna; Alonso, Mònica; Sanchez, Juan M; Anticó, Enriqueta

2013-03-01

A quantification method based on solid-phase microextraction followed by GC coupled to MS was developed for the determination of gas-liquid partition coefficients and for the air monitoring of a group of odour-causing compounds that had previously been found in wastewater samples including dimethyl disulphide, phenol, indole, skatole, octanal, nonanal, benzothiazole and some terpenes. Using a divinylbenzene/carboxen/polydimethylsiloxane fibre, adsorption kinetics have been studied to define an extraction time that would avoid coating saturation. It was found that for an extraction time of 10 min, external calibration could be performed in the range of 0.4-100 μg/m(3), with detection limits between 0.1 and 20 μg/m(3). Inter-day precision of the developed method was evaluated (n = 5) and RSD values between 12 and 24% were obtained for all compounds. The proposed method has been applied to the analysis of air samples surrounding a wastewater treatment plant in Catalonia (Spain). In all air samples evaluated, dimethyl disulphide, limonene and phenol were detected, and the first two were the compounds that showed the highest partition coefficients. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detecting microsatellites within genomes: significant variation among algorithms.

PubMed

Leclercq, Sébastien; Rivals, Eric; Jarne, Philippe

2007-04-18

Microsatellites are short, tandemly-repeated DNA sequences which are widely distributed among genomes. Their structure, role and evolution can be analyzed based on exhaustive extraction from sequenced genomes. Several dedicated algorithms have been developed for this purpose. Here, we compared the detection efficiency of five of them (TRF, Mreps, Sputnik, STAR, and RepeatMasker). Our analysis was first conducted on the human X chromosome, and microsatellite distributions were characterized by microsatellite number, length, and divergence from a pure motif. The algorithms work with user-defined parameters, and we demonstrate that the parameter values chosen can strongly influence microsatellite distributions. The five algorithms were then compared by fixing parameters settings, and the analysis was extended to three other genomes (Saccharomyces cerevisiae, Neurospora crassa and Drosophila melanogaster) spanning a wide range of size and structure. Significant differences for all characteristics of microsatellites were observed among algorithms, but not among genomes, for both perfect and imperfect microsatellites. Striking differences were detected for short microsatellites (below 20 bp), regardless of motif. Since the algorithm used strongly influences empirical distributions, studies analyzing microsatellite evolution based on a comparison between empirical and theoretical size distributions should therefore be considered with caution. We also discuss why a typological definition of microsatellites limits our capacity to capture their genomic distributions.

Detecting microsatellites within genomes: significant variation among algorithms

PubMed Central

Leclercq, Sébastien; Rivals, Eric; Jarne, Philippe

2007-01-01

Background Microsatellites are short, tandemly-repeated DNA sequences which are widely distributed among genomes. Their structure, role and evolution can be analyzed based on exhaustive extraction from sequenced genomes. Several dedicated algorithms have been developed for this purpose. Here, we compared the detection efficiency of five of them (TRF, Mreps, Sputnik, STAR, and RepeatMasker). Results Our analysis was first conducted on the human X chromosome, and microsatellite distributions were characterized by microsatellite number, length, and divergence from a pure motif. The algorithms work with user-defined parameters, and we demonstrate that the parameter values chosen can strongly influence microsatellite distributions. The five algorithms were then compared by fixing parameters settings, and the analysis was extended to three other genomes (Saccharomyces cerevisiae, Neurospora crassa and Drosophila melanogaster) spanning a wide range of size and structure. Significant differences for all characteristics of microsatellites were observed among algorithms, but not among genomes, for both perfect and imperfect microsatellites. Striking differences were detected for short microsatellites (below 20 bp), regardless of motif. Conclusion Since the algorithm used strongly influences empirical distributions, studies analyzing microsatellite evolution based on a comparison between empirical and theoretical size distributions should therefore be considered with caution. We also discuss why a typological definition of microsatellites limits our capacity to capture their genomic distributions. PMID:17442102

Infrasound array criteria for automatic detection and front velocity estimation of snow avalanches: towards a real-time early-warning system

NASA Astrophysics Data System (ADS)

Marchetti, E.; Ripepe, M.; Ulivieri, G.; Kogelnig, A.

2015-11-01

Avalanche risk management is strongly related to the ability to identify and timely report the occurrence of snow avalanches. Infrasound has been applied to avalanche research and monitoring for the last 20 years but it never turned into an operational tool to identify clear signals related to avalanches. We present here a method based on the analysis of infrasound signals recorded by a small aperture array in Ischgl (Austria), which provides a significant improvement to overcome this limit. The method is based on array-derived wave parameters, such as back azimuth and apparent velocity. The method defines threshold criteria for automatic avalanche identification by considering avalanches as a moving source of infrasound. We validate the efficiency of the automatic infrasound detection with continuous observations with Doppler radar and we show how the velocity of a snow avalanche in any given path around the array can be efficiently derived. Our results indicate that a proper infrasound array analysis allows a robust, real-time, remote detection of snow avalanches that is able to provide the number and the time of occurrence of snow avalanches occurring all around the array, which represent key information for a proper validation of avalanche forecast models and risk management in a given area.

Novel hybrid structure silica/CdTe/molecularly imprinted polymer: synthesis, specific recognition, and quantitative fluorescence detection of bovine hemoglobin.

PubMed

Li, Dong-Yan; He, Xi-Wen; Chen, Yang; Li, Wen-You; Zhang, Yu-Kui

2013-12-11

This work presented a novel strategy for the synthesis of the hybrid structure silica/CdTe/molecularly imprinted polymer (Si-NP/CdTe/MIP) to recognize and detect the template bovine hemoglobin (BHb). First, amino-functionalized silica nanoparticles (Si-NP) and carboxyl-terminated CdTe quantum dots (QDs) were assembled into composite nanoparticles (Si-NP/CdTe) using the EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) chemistry. Next, Si-NP/CdTe/MIP was synthesized by anchoring molecularly imprinted polymer (MIP) layer on the surface of Si-NP/CdTe through the sol-gel technique and surface imprinting technique. The hybrid structure possessed the selectivity of molecular imprinting technique and the sensitivity of CdTe QDs as well as well-defined morphology. The binding experiment and fluorescence method demonstrated its special recognition performance toward the template BHb. Under the optimized conditions, the fluorescence intensity of the Si-NP/CdTe/MIP decreased linearly with the increase of BHb in the concentration range 0.02-2.1 μM, and the detection limit was 9.4 nM. Moreover, the reusability and reproducibility and the successful applications in practical samples indicated the synthesis of Si-NP/CdTe/MIP provided an alternative solution for special recognition and determination of protein from real samples.

Serial detection of Epstein-Barr virus DNA in sera and peripheral blood leukocyte samples of pediatric renal allograft recipients with persistent mononucleosis-like symptoms defines patients at risk to develop post-transplant lymphoproliferative disease.

PubMed

Campe, Hartmut; Jaeger, Gundula; Abou-Ajram, Claudia; Nitschko, Hans; Griebel, Martin; Montoya, Carmen; Klare, Bernd; Koszinowski, Ulrich

2003-02-01

We tested blood samples of 25 pediatric renal transplant recipients for Epstein-Barr virus (EBV) DNA load by quantitative polymerase chain reaction (PCR). Eleven of these transplant recipients showed clinical persistent mononucleosis-like symptoms years after transplantation (Tx). A quantitation of EBV DNA by PCR in peripheral blood lymphocyte (PBL) and serum samples revealed variable EBV DNA titers. The majority of EBV PCR results in samples of the 14 asymptomatic transplant recipients was repeatedly below detection limit. In contrast, patients with mononucleosis-like symptoms showed persistent EBV genome titers over a period of 6 months, ranging from 75 to 18 750 copies/10 000 PBL and from 680 to 335 000 copies/mL serum, respectively. One child suffering from this mononucleosis-like condition developed an EBV-associated Burkitt-like lymphoma 29 months after Tx. Whereas clinical and histological investigations did not indicate a post-transplant lymphoproliferative disorder (PTLD) until tumor detection, EBV titers in PBL and serum had been high for at least 8 months. We propose that pediatric transplant recipients who show both, recurrent mononucleosis-like symptoms and a sustained high EBV genome load, are at increased risk for severe EBV-related post-transplant complications.

Diagnosis and classification of hematologic malignancies on the basis of genetics

PubMed Central

2017-01-01

Genomic analysis has greatly influenced the diagnosis and clinical management of patients affected by diverse forms of hematologic malignancies. Here, we review how genetic alterations define subclasses of patients with acute leukemias, myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPNs), non-Hodgkin lymphomas, and classical Hodgkin lymphoma. These include new subtypes of acute myeloid leukemia defined by mutations in RUNX1 or BCR-ABL1 translocations as well as a constellation of somatic structural DNA alterations in acute lymphoblastic leukemia. Among patients with MDS, detection of mutations in SF3B1 define a subgroup of patients with the ring sideroblast form of MDS and a favorable prognosis. For patients with MPNs, detection of the BCR-ABL1 fusion delineates chronic myeloid leukemia from classic BCR-ABL1− MPNs, which are largely defined by mutations in JAK2, CALR, or MPL. In the B-cell lymphomas, detection of characteristic rearrangements involving MYC in Burkitt lymphoma, BCL2 in follicular lymphoma, and MYC/BCL2/BCL6 in high-grade B-cell lymphomas are essential for diagnosis. In T-cell lymphomas, anaplastic large-cell lymphoma is defined by mutually exclusive rearrangements of ALK, DUSP22/IRF4, and TP63. Genetic alterations affecting TP53 and the mutational status of the immunoglobulin heavy-chain variable region are important in clinical management of chronic lymphocytic leukemia. Additionally, detection of BRAFV600E mutations is helpful in the diagnosis of classical hairy cell leukemia and a number of histiocytic neoplasms. Numerous additional examples provided here demonstrate how clinical evaluation of genomic alterations have refined classification of myeloid neoplasms and major forms of lymphomas arising from B, T, or natural killer cells. PMID:28600336

A method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry.

PubMed

Parkinson, I S; Ward, M K; Kerr, D N

1982-10-27

A simple but reliable method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry is described. No preparatory procedures are required for water samples, although serum is mixed with a wetting agent (Triton X-100) to allow complete combustion of the samples and to improve analytical precision. Precautions to prevent contamination during sample handling are discussed and instrumental parameters are defined. The method has a sensitivity of 35.5 pg and detection limits of 2.3 micrograms Al/l for serum and 1.3 micrograms Al/l for water. The method was used to determine the aluminium concentration in serum of 46 normal subjects. The mean aluminium content was 7.3 micrograms/l (range 2--15 micrograms/l.

Policy, phylogeny, and the parasite.

PubMed

Stentiford, Grant D; Feist, Stephen W; Stone, David M; Peeler, Edmund J; Bass, David

2014-06-01

Animal diseases gain political attention by their inclusion on lists of global bodies such as those of the World Organisation for Animal Health (OIE). Inclusion requires national governments to report outbreaks promptly but may lead to trading restrictions between nations in an attempt to limit spread. Detection therefore has consequences that may have direct impact from farm to state levels. We consider here current approaches to discriminating listed parasites from related but unlisted counterparts. We outline necessary drivers for the discrimination of important taxa and how these may be influenced by national policies. Further, we propose a set of 'best practice' measures, broadly based upon current taxonomic philosophies for protists and metazoans, that should be applied when defining taxa for listing as notifiable. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

European research priorities for intracerebral haemorrhage.

PubMed

Steiner, Thorsten; Petersson, Jesper; Al-Shahi Salman, Rustam; Christensen, Hanne; Cordonnier, Charlotte; Csiba, Laszlo; Harnof, Sagi; Krieger, Derk; Mendelow, David; Molina, Carlos; Montaner, Joan; Overgaard, Karsten; Roine, Risto O; Schmutzhard, Erich; Tatlisumak, Turgut; Toni, Danilo; Stapf, Christian

2011-01-01

Over 2 million people are affected by intracerebral haemorrhage (ICH) worldwide every year, one third of them dying within 1 month, and many survivors being left with permanent disability. Unlike most other stroke types, the incidence, morbidity and mortality of ICH have not declined over time. No standardised diagnostic workup for the detection of the various underlying causes of ICH currently exists, and the evidence for medical or surgical therapeutic interventions remains limited. A dedicated European research programme for ICH is needed to identify ways to reduce the burden of ICH-related death and disability. The European Research Network on Intracerebral Haemorrhage EURONICH is a multidisciplinary academic research collaboration that has been established to define current research priorities and to conduct large clinical studies on all aspects of ICH. Copyright © 2011 S. Karger AG, Basel.

Detection and characterization of multi-filament evolution during resistive switching

DOE PAGES

Mickel, Patrick R.; Lohn, Andrew J.; Marinella, Matthew J.

2014-08-05

We present resistive switching data in TaO x memristors displaying signatures of multi-filament switching modes, and develop a geometrically defined equivalent circuit to separate the individual resistances and powers dissipated in each filament. Using these resolved values, we compare the individual switching curves of each filament and demonstrate that the switching data of each filament collapse onto a single switching curve determined by the analytical steady-state resistive switching solution for filamentary switching. Analyzing our results in terms of this solution, we determine the switching temperature, heat flow, conductivity, and time evolving areas of each filament during resistive switching. Finally, wemore » discuss operational modes which may limit the formation of additional conducting filaments, potentially leading to increased device endurance.« less

Analysis of Temperature Variability in Medication Storage Compartments in Emergency Transport Helicopters.

PubMed

O'Donnell, Margaret A; Whitfield, Justin

The purpose of this study was to determine whether the temperature in medication storage compartments in air medical helicopters was within United States Pharmacopeia (USP)-defined limits for controlled room temperature. This was a prospective study using data obtained from a continuous temperature monitoring device. A total of 4 monitors were placed within 2 medication storage locations in 2 identical helicopters. The data collection period lasted 2 weeks during the summer and winter seasons. Data retrieved from monitors were compared against USP parameters for proper medication storage. Results documented temperatures outside the acceptable range a majority of the time with temperatures above the high limit during summer and below the low limit during winter. The study determined that compartments used for medication storage frequently fell outside of the range for USP-defined limits for medication storage. Flight programs should monitor storage areas, carefully taking actions to keep medication within defined ranges. Copyright © 2016 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.

Censoring: a new approach for detection limits in total-reflection X-ray fluorescence

NASA Astrophysics Data System (ADS)

Pajek, M.; Kubala-Kukuś, A.; Braziewicz, J.

2004-08-01

It is shown that the detection limits in the total-reflection X-ray fluorescence (TXRF), which restrict quantification of very low concentrations of trace elements in the samples, can be accounted for using the statistical concept of censoring. We demonstrate that the incomplete TXRF measurements containing the so-called "nondetects", i.e. the non-measured concentrations falling below the detection limits and represented by the estimated detection limit values, can be viewed as the left random-censored data, which can be further analyzed using the Kaplan-Meier (KM) method correcting for nondetects. Within this approach, which uses the Kaplan-Meier product-limit estimator to obtain the cumulative distribution function corrected for the nondetects, the mean value and median of the detection limit censored concentrations can be estimated in a non-parametric way. The Monte Carlo simulations performed show that the Kaplan-Meier approach yields highly accurate estimates for the mean and median concentrations, being within a few percent with respect to the simulated, uncensored data. This means that the uncertainties of KM estimated mean value and median are limited in fact only by the number of studied samples and not by the applied correction procedure for nondetects itself. On the other hand, it is observed that, in case when the concentration of a given element is not measured in all the samples, simple approaches to estimate a mean concentration value from the data yield erroneous, systematically biased results. The discussed random-left censoring approach was applied to analyze the TXRF detection-limit-censored concentration measurements of trace elements in biomedical samples. We emphasize that the Kaplan-Meier approach allows one to estimate the mean concentrations being substantially below the mean level of detection limits. Consequently, this approach gives a new access to lower the effective detection limits for TXRF method, which is of prime interest for investigation of metallic impurities on the silicon wafers.

Ultrasensitive Detection of Shigella Species in Blood and Stool.

PubMed

Luo, Jieling; Wang, Jiapeng; Mathew, Anup S; Yau, Siu-Tung

2016-02-16

A modified immunosensing system with voltage-controlled signal amplification was used to detect Shigella in stool and blood matrixes at the single-digit CFU level. Inactivated Shigella was spiked in these matrixes and detected directly. The detection was completed in 78 min. Detection limits of 21 CFU/mL and 18 CFU/mL were achieved in stool and blood, respectively, corresponding to 2-7 CFUs immobilized on the detecting electrode. The outcome of the detection of extremely low bacterium concentration, i.e., below 100 CFU/mL, blood samples show a random nature. An analysis of the detection probabilities indicates the correlation between the sample volume and the success of detection and suggests that sample volume is critical for ultrasensitive detection of bacteria. The calculated detection limit is qualitatively in agreement with the empirically determined detection limit. The demonstrated ultrasensitive detection of Shigella on the single-digit CFU level suggests the feasibility of the direct detection of the bacterium in the samples without performing a culture.

Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

NASA Astrophysics Data System (ADS)

Voichick, Nicholas; Topping, David J.; Griffiths, Ronald E.

2018-03-01

Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator-prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples) are necessary to correct these low false turbidity measurements and accurately measure turbidity.

Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

USGS Publications Warehouse

Voichick, Nicholas; Topping, David; Griffiths, Ronald

2018-01-01

Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator–prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples) are necessary to correct these low false turbidity measurements and accurately measure turbidity.

A validated analytical method to study the long-term stability of natural and synthetic glucocorticoids in livestock urine using ultra-high performance liquid chromatography coupled to Orbitrap-high resolution mass spectrometry.

PubMed

De Clercq, Nathalie; Julie, Vanden Bussche; Croubels, Siska; Delahaut, Philippe; Vanhaecke, Lynn

2013-08-02

Due to their growth-promoting effects, the use of synthetic glucocorticoids is strictly regulated in the European Union (Council Directive 2003/74/EC). In the frame of the national control plans, which should ensure the absence of residues in food products of animal origin, in recent years, a higher frequency of prednisolone positive bovine urines has been observed. This has raised questions with respect to the stability of natural corticoids in the respective urine samples and their potential to be transformed into synthetic analogs. In this study, a ultra high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) methodology was developed to examine the stability of glucocorticoids in bovine urine under various storage conditions (up to 20 weeks) and to define suitable conditions for sample handling and storage, using an Orbitrap Exactive™. To this end, an extraction procedure was optimized using a Plackett-Burman experimental design to determine the key conditions for optimal extraction of glucocorticoids from urine. Next, the analytical method was successfully validated according to the guidelines of CD 2002/657/EC. Decision limits and detection capabilities for prednisolone, prednisone and methylprednisolone ranged, respectively, from 0.1 to 0.5μgL(-1) and from 0.3 to 0.8μgL(-1). For the natural glucocorticoids limits of detection and limits of quantification for dihydrocortisone, cortisol and cortisone ranged, respectively, from 0.1 to 0.2μgL(-1) and from 0.3 to 0.8μgL(-1). The stability study demonstrated that filter-sterilization of urine, storage at -80°C, and acidic conditions (pH 3) were optimal for preservation of glucocorticoids in urine and able to significantly limit degradation up to 20 weeks. Copyright © 2013 Elsevier B.V. All rights reserved.

Virtual rigid body: a new optical tracking paradigm in image-guided interventions

NASA Astrophysics Data System (ADS)

Cheng, Alexis; Lee, David S.; Deshmukh, Nishikant; Boctor, Emad M.

2015-03-01

Tracking technology is often necessary for image-guided surgical interventions. Optical tracking is one the options, but it suffers from line of sight and workspace limitations. Optical tracking is accomplished by attaching a rigid body marker, having a pattern for pose detection, onto a tool or device. A larger rigid body results in more accurate tracking, but at the same time large size limits its usage in a crowded surgical workspace. This work presents a prototype of a novel optical tracking method using a virtual rigid body (VRB). We define the VRB as a 3D rigid body marker in the form of pattern on a surface generated from a light source. Its pose can be recovered by observing the projected pattern with a stereo-camera system. The rigid body's size is no longer physically limited as we can manufacture small size light sources. Conventional optical tracking also requires line of sight to the rigid body. VRB overcomes these limitations by detecting a pattern projected onto the surface. We can project the pattern onto a region of interest, allowing the pattern to always be in the view of the optical tracker. This helps to decrease the occurrence of occlusions. This manuscript describes the method and results compared with conventional optical tracking in an experiment setup using known motions. The experiments are done using an optical tracker and a linear-stage, resulting in targeting errors of 0.38mm+/-0.28mm with our method compared to 0.23mm+/-0.22mm with conventional optical markers. Another experiment that replaced the linear stage with a robot arm resulted in rotational errors of 0.50+/-0.31° and 2.68+/-2.20° and the translation errors of 0.18+/-0.10 mm and 0.03+/-0.02 mm respectively.

Validation of a method for the determination of 120 pesticide residues in apples and cucumbers by LC-MS/MS.

PubMed

Ramadan, Gouda; Al Jabir, Muna; Alabdulmalik, Najat; Mohammed, Ali

2016-05-01

Most countries have clearly defined regulations governing the use of pesticides in agricultural activity. The application of pesticides in agriculture usually leads to a residual amount of these pesticides on food products such as fruit and vegetables. The presence of pesticide residues on these foods destined for human consumption may pose food safety risks to consumers. To protect consumers, national authorities have established maximum limits for pesticide residues in foods. These limits can only be enforced if there are methods available to detect and monitor their concentrations in the applicable food products. To support the enforcement of this legislation, we have developed a multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of 120 pesticide residues in apples and cucumbers which has been validated and implemented in the routine monitoring and surveillance programme for these pesticides. In this method, apple and cucumber samples are extracted using the QuEChERS method (quick, easy, cheap, effective, rugged, and safe) and the extracts were analyzed directly by LC-MS/MS. The mean recoveries at three different concentrations of 0.01 µg/g , 0.05 µg/g, and 0.1 µg/g over the analytical range varied between 70 and 120%. The repeatability of the method expressed as %RSD was less than 20%. The limit of detection (LOD) of the method ranged between 0.0014 and 0.0110 µg/g for apples and between 0.0012 and 0.0075 µg/g for cucumbers. The limit of quantification (LOQ) of the method was 0.01 µg/g for apples and cucumbers. The method has been used for the analysis of over 600 apple and 550 cucumber samples over the past two years. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Fluorescein Dye Penetration in Round Top Rhyolite (Hudspeth County, Texas, USA) to Reveal Micro-permeability and Optimize Grain Size for Heavy REE Heap Leach

NASA Astrophysics Data System (ADS)

Negron, L. M.; Clague, J. W.; Gorski, D.; Amaya, M. A.; Pingitore, N. E.

2013-12-01

Millimeter- and micrometer-scale permeability of fine-grained igneous rocks has generated limited research interest. Nonetheless, the scale and distribution of such micro-permeability determines fluid penetration and pathways, parameters that define both the ability to heap leach a rock and the optimal grain size for such an operation. Texas Rare Earth Resources is evaluating the possibility of heap leaching of yttrium and heavy rare earth elements (YHREE) from the peraluminous rhyolite laccolith that forms one-mile-diameter Round Top Mountain. The YHREEs in this immense, surface-exposed deposit (minimum 1.6 billion tons, Texas Bureau Economic Geology) are dilute and diffuse, suggesting leaching as the best option for recovery. The REE grade is 0.05% and YHREEs comprise more than 70% of the total REE content. The YHREEs are hosted exclusively in micron-scale yttrofluorite grains, which proved soluble in dilute sulfuric acid. Laboratory experiments showed YHREE recoveries of up to 90%. Within limits, recoveries decrease with larger grain sizes, and increase with acid strength and exposure time. Our research question centers on dissolution effectiveness: Is YHREE recovery, relative to grain size, limited by (1) diffusion time of acid into, and dissolved solids, including YHREEs, out of the micro-permeability paths inherent in the rock particles; (2) the effective lengths of the natural micro-permeability paths in the rock; or (3) the putative role of the acid in dissolving new micro-paths into the grains? The maximum grain size should not exceed twice the typical path length (unless acid creates new paths), lest YHREEs in the core of a larger grain than that not be reached by acid. If instead diffusion time is limiting, longer leach time may prove effective. Rather than perform an extensive and expensive series of laboratory leaching experiments--some of which would be several months in duration--to determine optimal grain size, we developed a technique to efficiently determine the limits of penetration of water into the rhyolite. We cut parallel-sided slabs of Round Top rhyolite at staged thickness up to 10 mm. We then wet one side and view the opposite side over time under UV light to detect breakthrough of the fluorescein dye. Because of its extremely low visual detection limits, well below the ppm level, the dye has been widely used in biochemical research, as a tracer in surface and ground water studies, in delineating invisible cracks in such structural material as motor blocks, and in detecting corneal abrasions. We have been successful in detecting breakthrough at different rhyolite thicknesses. Continuing studies focus on mapping of the 2-dimensional distribution of the permeability via hand lens and low-power microscope; use of visible light dyes; and examination of specimens pre- and post-acid leaching to determine whether acid exposure produced significant new micro-permeability.

Laboratory sample stability. Is it possible to define a consensus stability function? An example of five blood magnitudes.

PubMed

Gómez Rioja, Rubén; Martínez Espartosa, Débora; Segovia, Marta; Ibarz, Mercedes; Llopis, María Antonia; Bauça, Josep Miquel; Marzana, Itziar; Barba, Nuria; Ventura, Monserrat; García Del Pino, Isabel; Puente, Juan José; Caballero, Andrea; Gómez, Carolina; García Álvarez, Ana; Alsina, María Jesús; Álvarez, Virtudes

2018-05-05

The stability limit of an analyte in a biological sample can be defined as the time required until a measured property acquires a bias higher than a defined specification. Many studies assessing stability and presenting recommendations of stability limits are available, but differences among them are frequent. The aim of this study was to classify and to grade a set of bibliographic studies on the stability of five common blood measurands and subsequently generate a consensus stability function. First, a bibliographic search was made for stability studies for five analytes in blood: alanine aminotransferase (ALT), glucose, phosphorus, potassium and prostate specific antigen (PSA). The quality of every study was evaluated using an in-house grading tool. Second, the different conditions of stability were uniformly defined and the percent deviation (PD%) over time for each analyte and condition were scattered while unifying studies with similar conditions. From the 37 articles considered as valid, up to 130 experiments were evaluated and 629 PD% data were included (106 for ALT, 180 for glucose, 113 for phosphorus, 145 for potassium and 85 for PSA). Consensus stability equations were established for glucose, potassium, phosphorus and PSA, but not for ALT. Time is the main variable affecting stability in medical laboratory samples. Bibliographic studies differ in recommedations of stability limits mainly because of different specifications for maximum allowable error. Definition of a consensus stability function in specific conditions can help laboratories define stability limits using their own quality specifications.

The Effect of Symbology Location and Format on Attentional Deployment within a Cockpit Display of Traffic Information

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Liao, Min-Ju; Tse, Stephen

2003-01-01

The present experiment employed target detection tasks to investigate attentional deployment during visual search for target aircraft symbols on a cockpit display of traffic information (CDTI). Targets were defined by either a geometric property (aircraft on a collision course with Ownship) or a textual property (aircraft with associated altitude tags indicating an even altitude level). Effects of target location and target brightness (highlighting) were examined. Target location was systematically related to target detection time, and this interacted with the target's defining property (collision geometry or associated text). Highlighting (which was not linked to whether an aircraft symbol was the target) did not influence target detection time.

Content modification attacks on consensus seeking multi-agent system with double-integrator dynamics.

PubMed

Dong, Yimeng; Gupta, Nirupam; Chopra, Nikhil

2016-11-01

In this paper, vulnerability of a distributed consensus seeking multi-agent system (MAS) with double-integrator dynamics against edge-bound content modification cyber attacks is studied. In particular, we define a specific edge-bound content modification cyber attack called malignant content modification attack (MCoMA), which results in unbounded growth of an appropriately defined group disagreement vector. Properties of MCoMA are utilized to design detection and mitigation algorithms so as to impart resilience in the considered MAS against MCoMA. Additionally, the proposed detection mechanism is extended to detect the general edge-bound content modification attacks (not just MCoMA). Finally, the efficacies of the proposed results are illustrated through numerical simulations.

Content modification attacks on consensus seeking multi-agent system with double-integrator dynamics

NASA Astrophysics Data System (ADS)

Dong, Yimeng; Gupta, Nirupam; Chopra, Nikhil

2016-11-01

In this paper, vulnerability of a distributed consensus seeking multi-agent system (MAS) with double-integrator dynamics against edge-bound content modification cyber attacks is studied. In particular, we define a specific edge-bound content modification cyber attack called malignant content modification attack (MCoMA), which results in unbounded growth of an appropriately defined group disagreement vector. Properties of MCoMA are utilized to design detection and mitigation algorithms so as to impart resilience in the considered MAS against MCoMA. Additionally, the proposed detection mechanism is extended to detect the general edge-bound content modification attacks (not just MCoMA). Finally, the efficacies of the proposed results are illustrated through numerical simulations.

Characteristics of color memory for natural scenes

NASA Astrophysics Data System (ADS)

Amano, Kinjiro; Uchikawa, Keiji; Kuriki, Ichiro

2002-08-01

To study the characteristics of color memory for natural images, a memory-identification task was performed with differing color contrasts; three of the contrasts were defined by chromatic and luminance components of the image, and the others were defined with respect to the categorical colors. After observing a series of pictures successively, subjects identified the pictures using a confidence rating. Detection of increased contrasts tended to be harder than detection of decreased contrasts, suggesting that the chromaticness of pictures is enhanced in memory. Detecting changes within each color category was more difficult than across the categories. A multiple mechanism that processes color differences and categorical colors is briefly considered. 2002 Optical Society of America

Performance of the New Aptima HCV Quant Dx Assay in Comparison to the Cobas TaqMan HCV2 Test for Use with the High Pure System in Detection and Quantification of Hepatitis C Virus RNA in Plasma or Serum.

PubMed

Schalasta, Gunnar; Speicher, Andrea; Börner, Anna; Enders, Martin

2016-04-01

Quantitating the level of hepatitis C virus (HCV) RNA is the standard of care for monitoring HCV-infected patients during treatment. The performances of commercially available assays differ for precision, limit of detection, and limit of quantitation (LOQ). Here, we compare the performance of the Hologic Aptima HCV Quant Dx assay (Aptima) to that of the Roche Cobas TaqMan HCV test, version 2.0, using the High Pure system (HPS/CTM), considered a reference assay since it has been used in trials defining clinical decision points in patient care. The assays' performance characteristics were assessed using HCV RNA reference panels and plasma/serum from chronically HCV-infected patients. The agreement between the assays for the 3 reference panels was good, with a difference in quantitation values of <0.5 log. High concordance was demonstrated between the assays for 245 clinical samples (kappa = 0.80; 95% confidence interval [CI], 0.720 to 0.881); however, Aptima detected and/or quantitated 20 samples that HPS/CTM did not detect, while Aptima did not detect 1 sample that was quantitated by HPS/CTM. For the 165 samples quantitated by both assays, the values were highly correlated (R= 0.98;P< 0.0001). The linearity of quantitation from concentrations of 1.4 to 6 log was excellent for both assays for all HCV genotypes (GT) tested (GT 1a, 1b, 2b, and 3a) (R(2)> 0.99). The assays had similar levels of total and intra-assay variability across all genotypes at concentrations from 1,000 to 25 IU/ml. Aptima had a greater analytical sensitivity, quantitating more than 50% of replicates at 25-IU/ml target. Aptima showed performance characteristics comparable to those of HPS/CTM and increased sensitivity, making it suitable for use as a clinical diagnostic tool on the fully automated Panther platform. Copyright © 2016 Schalasta et al.

Feasibility of detecting near-surface feature with Rayleigh-wave diffraction

USGS Publications Warehouse

Xia, J.; Nyquist, Jonathan E.; Xu, Y.; Roth, M.J.S.; Miller, R.D.

2007-01-01

Detection of near-surfaces features such as voids and faults is challenging due to the complexity of near-surface materials and the limited resolution of geophysical methods. Although multichannel, high-frequency, surface-wave techniques can provide reliable shear (S)-wave velocities in different geological settings, they are not suitable for detecting voids directly based on anomalies of the S-wave velocity because of limitations on the resolution of S-wave velocity profiles inverted from surface-wave phase velocities. Therefore, we studied the feasibility of directly detecting near-surfaces features with surface-wave diffractions. Based on the properties of surface waves, we have derived a Rayleigh-wave diffraction traveltime equation. We also have solved the equation for the depth to the top of a void and an average velocity of Rayleigh waves. Using these equations, the depth to the top of a void/fault can be determined based on traveltime data from a diffraction curve. In practice, only two diffraction times are necessary to define the depth to the top of a void/fault and the average Rayleigh-wave velocity that generates the diffraction curve. We used four two-dimensional square voids to demonstrate the feasibility of detecting a void with Rayleigh-wave diffractions: a 2??m by 2??m with a depth to the top of the void of 2??m, 4??m by 4??m with a depth to the top of the void of 7??m, and 6??m by 6??m with depths to the top of the void 12??m and 17??m. We also modeled surface waves due to a vertical fault. Rayleigh-wave diffractions were recognizable for all these models after FK filtering was applied to the synthetic data. The Rayleigh-wave diffraction traveltime equation was verified by the modeled data. Modeling results suggested that FK filtering is critical to enhance diffracted surface waves. A real-world example is presented to show how to utilize the derived equation of surface-wave diffractions. ?? 2006 Elsevier B.V. All rights reserved.

Diurnal remote sensing of coastal/oceanic waters: a radiometric analysis for Geostationary Coastal and Air Pollution Events.

PubMed

Pahlevan, Nima; Lee, Zhongping; Hu, Chuanmin; Schott, John R

2014-02-01

Optical remote sensing systems aboard geostationary platforms can provide high-frequency observations of bio-optical properties in dynamical coastal/oceanic waters. From the end-user standpoint, it is recognized that the fidelity of daily science products relies heavily on the radiometric sensitivity/performance of the imaging system. This study aims to determine the theoretical detection limits for bio-optical properties observed diurnally from a geostationary orbit. The analysis is based upon coupled radiative transfer simulations and the minimum radiometric requirements defined for the GEOstationary Coastal and Air Pollution Events (GEO-CAPE) mission. The diurnal detection limits are found for the optically active constituents of water, including near-surface concentrations of chlorophyll-a (CHL) and total suspended solids (TSS), and the absorption of colored dissolved organic matter (aCDOM). The diurnal top-of-atmosphere radiance (Lt) is modeled for several locations across the field of regard (FOR) to investigate the radiometric sensitivity at different imaging geometries. It is found that, in oceanic waters (CHL=0.07  mg/m3), detecting changes smaller than 0.01  mg/m3 in CHL is feasible for all locations and hours except for late afternoon observations on the edge of the FOR. For more trophic/turbid waters (0.6