Co-Channel Interference Mitigation Using Satellite Based Receivers

DTIC Science & Technology

2014-12-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RECEIVERS by John E. Patterson...07-02-2012 to 12-19-2014 4. TITLE AND SUBTITLE CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RE- CEIVERS 5. FUNDING NUMBERS 6. AUTHOR(S...Approved for public release; distribution is unlimited CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RECEIVERS John E. Patterson Commander

40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by a...

40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by a...

40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by a...

40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Inter-precursor mitigation measures... § 93.164 Inter-precursor mitigation measures and offsets. Federal agencies must reduce the same type of... mitigation measures of different precursors of the same criteria pollutant, if such trades are allowed by a...

NOTE: Cell-phone interference with pocket dosimeters

NASA Astrophysics Data System (ADS)

Djajaputra, David; Nehru, Ramasamy; Bruch, Philip M.; Ayyangar, Komanduri M.; Raman, Natarajan V.; Enke, Charles A.

2005-05-01

Accurate reporting of personal dose is required by regulation for hospital personnel that work with radioactive material. Pocket dosimeters are commonly used for monitoring this personal dose. We show that operating a cell phone in the vicinity of a pocket dosimeter can introduce large and erroneous readings of the dosimeter. This note reports a systematic study of this electromagnetic interference. We found that simple practical measures are enough to mitigate this problem, such as increasing the distance between the cell phone and the dosimeter or shielding the dosimeter, while maintaining its sensitivity to ionizing radiation, by placing it inside a common anti-static bag.

Experimental demonstration of an efficient hybrid equalizer for short-reach optical SSB systems

NASA Astrophysics Data System (ADS)

Zhu, Mingyue; Ying, Hao; Zhang, Jing; Yi, Xingwen; Qiu, Kun

2018-02-01

We propose an efficient enhanced hybrid equalizer combining the feed forward equalization (FFE) with a modified Volterra filter to mitigate the linear and nonlinear interference for the short-reach optical single side-band (SSB) system. The optical SSB signal is generated by a relatively low-cost dual-drive Mach-Zehnder modulator (DDMZM). The two driving signals are a pair of Hilbert signals with Nyquist pulse-shaped four-level pulse amplitude modulation (NPAM-4). After the fiber transmission, the neighboring received symbols are strongly correlated due to the pulse spreading in time domain caused by the chromatic dispersion (CD). At the receiver equalization stage, the FFE followed by higher order terms of modified Volterra filter, which utilizes the forward and backward neighboring symbols to construct the kernels with strong correlation, are used as an enhanced hybrid equalizer to mitigate the inter symbol interference (ISI) and nonlinear distortion due to the interaction of the CD and the square-law detection. We experimentally demonstrate that the optical SSB NPAM-4 signal of 40 Gb/s transmitting over 80 km standard single mode fiber (SSMF) with a bit-error-rate (BER) of 7 . 59 × 10-4.

Pilot self-coding applied in optical OFDM systems

NASA Astrophysics Data System (ADS)

Li, Changping; Yi, Ying; Lee, Kyesan

2015-04-01

This paper studies the frequency offset correction technique which can be applied in optical OFDM systems. Through theoretical analysis and computer simulations, we can observe that our proposed scheme named pilot self-coding (PSC) has a distinct influence for rectifying the frequency offset, which could mitigate the OFDM performance deterioration because of inter-carrier interference and common phase error. The main approach is to assign a pilot subcarrier before data subcarriers and copy this subcarrier sequence to the symmetric side. The simulation results verify that our proposed PSC is indeed effective against the high degree of frequency offset.

New hybrid frequency reuse method for packet loss minimization in LTE network.

PubMed

Ali, Nora A; El-Dakroury, Mohamed A; El-Soudani, Magdi; ElSayed, Hany M; Daoud, Ramez M; Amer, Hassanein H

2015-11-01

This paper investigates the problem of inter-cell interference (ICI) in Long Term Evolution (LTE) mobile systems, which is one of the main problems that causes loss of packets between the base station and the mobile station. Recently, different frequency reuse methods, such as soft and fractional frequency reuse, have been introduced in order to mitigate this type of interference. In this paper, minimizing the packet loss between the base station and the mobile station is the main concern. Soft Frequency Reuse (SFR), which is the most popular frequency reuse method, is examined and the amount of packet loss is measured. In order to reduce packet loss, a new hybrid frequency reuse method is implemented. In this method, each cell occupies the same bandwidth of the SFR, but the total system bandwidth is greater than in SFR. This will provide the new method with a lot of new sub-carriers from the neighboring cells to reduce the ICI which represents a big problem in many applications and causes a lot of packets loss. It is found that the new hybrid frequency reuse method has noticeable improvement in the amount of packet loss compared to SFR method in the different frequency bands. Traffic congestion management in Intelligent Transportation system (ITS) is one of the important applications that is affected by the packet loss due to the large amount of traffic that is exchanged between the base station and the mobile node. Therefore, it is used as a studied application for the proposed frequency reuse method and the improvement in the amount of packet loss reached 49.4% in some frequency bands using the new hybrid frequency reuse method.

A Location-Based Duplex Scheme for Cost Effective Rural Broadband Connectivity Using IEEE 802.22 Cognitive Radio Based Wireless Regional Area Networks

NASA Astrophysics Data System (ADS)

Kalidoss, R.; Bhagyaveni, M. A.; Vishvaksenan, K. S.

2014-08-01

The search for a method of utilizing the scarce spectrum in an efficient manner is an active area of research in both academic and industrial communities. IEEE 802.22 is a standard for wireless regional area network (WRAN) based on cognitive radio (CR) that operates over underutilized portions of TV bands (54-862 MHz). Time division duplex (TDD)-based WRAN cells have such advantages as dynamic traffic allocation, traffic asymmetry to users and ease of spectrum allocation. However, these cells suffer from severe cross time slot (CTS) interference when the frames of the cells are not synchronized with adjacent WRAN cells. In this paper, we evaluate the location-based duplex (LBD) scheme for eliminating the CTS interference. The proposed LBD system is much more flexible and efficient in providing asymmetric data service and eliminating CTS interference by exploiting the advantages of both TDD and frequency division duplex (FDD) schemes. We also compare the performance of LBD systems with virtual cell concepts. Furthermore, our simulation results reveal that LBD-based systems outperform the virtual cell approach in terms of the low signal-to-interference (SIR) ratio requirement by mitigating the effects of CTS.

Experimental demonstration of iterative post-equalization algorithm for 37.5-Gbaud PM-16QAM quad-carrier Terabit superchannel.

PubMed

Jia, Zhensheng; Chien, Hung-Chang; Cai, Yi; Yu, Jianjun; Zhang, Chengliang; Li, Junjie; Ma, Yiran; Shang, Dongdong; Zhang, Qi; Shi, Sheping; Wang, Huitao

2015-02-09

We experimentally demonstrate a quad-carrier 1-Tb/s solution with 37.5-GBaud PM-16QAM signal over 37.5-GHz optical grid at 6.7 b/s/Hz net spectral efficiency. Digital Nyquist pulse shaping at the transmitter and post-equalization at the receiver are employed to mitigate the impairments of joint inter-symbol-interference (ISI) and inter-channel-interference (ICI) symbol degradation. The post-equalization algorithms consist of one sample/symbol based decision-directed least mean square (DD-LMS) adaptive filter, digital post filter and maximum likelihood sequence estimation (MLSE), and a positive iterative process among them. By combining these algorithms, the improvement as much as 4-dB OSNR (0.1nm) at SD-FEC limit (Q(2) = 6.25 corresponding to BER = 2.0e-2) is obtained when compared to no such post-equalization process, and transmission over 820-km EDFA-only standard single-mode fiber (SSMF) link is achieved for two 1.2-Tb/s signals with the averaged Q(2) factor larger than 6.5 dB for all sub-channels. Additionally, 50-GBaud 16QAM operating at 1.28 samples/symbol in a DAC is also investigated and successful transmission over 410-km SSMF link is achieved at 62.5-GHz optical grid.

40 CFR 93.164 - Inter-precursor mitigation measures and offsets.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Inter-precursor mitigation measures and...-precursor mitigation measures and offsets. Federal agencies must reduce the same type of pollutant as being increased by the Federal action except the State or Tribe may approve offsets or mitigation measures of...

Drug Target Interference in Immunogenicity Assays: Recommendations and Mitigation Strategies.

PubMed

Zhong, Zhandong Don; Clements-Egan, Adrienne; Gorovits, Boris; Maia, Mauricio; Sumner, Giane; Theobald, Valerie; Wu, Yuling; Rajadhyaksha, Manoj

2017-11-01

Sensitive and specific methodology is required for the detection and characterization of anti-drug antibodies (ADAs). High-quality ADA data enables the evaluation of potential impact of ADAs on the drug pharmacokinetic profile, patient safety, and efficacious response to the drug. Immunogenicity assessments are typically initiated at early stages in preclinical studies and continue throughout the drug development program. One of the potential bioanalytical challenges encountered with ADA testing is the need to identify and mitigate the interference mediated by the presence of soluble drug target. A drug target, when present at sufficiently high circulating concentrations, can potentially interfere with the performance of ADA and neutralizing antibody (NAb) assays, leading to either false-positive or, in some cases, false-negative ADA and NAb assay results. This publication describes various mechanisms of assay interference by soluble drug target, as well as strategies to recognize and mitigate such target interference. Pertinent examples are presented to illustrate the impact of target interference on ADA and NAb assays as well as several mitigation strategies, including the use of anti-target antibodies, soluble versions of the receptors, target-binding proteins, lectins, and solid-phase removal of targets. Furthermore, recommendations for detection and mitigation of such interference in different formats of ADA and NAb assays are provided.

75 FR 17874 - Digital Audio Broadcasting Systems and Their Impact on the Terrestrial Radio Broadcast Service

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-08

... power (ERP), and implements interference mitigation and remediation procedures to resolve promptly..., and the interference mitigation and remediation procedures will make certain that permissible... ERP to more than 4% of authorized analog ERP. 4. Establishes interference remediation procedures that...

Investigation of Inter-Node B Macro Diversity for Single-Carrier Based Radio Access in Evolved UTRA Uplink

NASA Astrophysics Data System (ADS)

Kawai, Hiroyuki; Morimoto, Akihito; Higuchi, Kenichi; Sawahashi, Mamoru

This paper investigates the gain of inter-Node B macro diversity for a scheduled-based shared channel using single-carrier FDMA radio access in the Evolved UTRA (UMTS Terrestrial Radio Access) uplink based on system-level simulations. More specifically, we clarify the gain of inter-Node B soft handover (SHO) with selection combining at the radio frame length level (=10msec) compared to that for hard handover (HHO) for a scheduled-based shared data channel, considering the gains of key packet-specific techniques including channel-dependent scheduling, adaptive modulation and coding (AMC), hybrid automatic repeat request (ARQ) with packet combining, and slow transmission power control (TPC). Simulation results show that the inter-Node B SHO increases the user throughput at the cell edge by approximately 10% for a short cell radius such as 100-300m due to the diversity gain from a sudden change in other-cell interference, which is a feature specific to full scheduled-based packet access. However, it is also shown that the gain of inter-Node B SHO compared to that for HHO is small in a macrocell environment when the cell radius is longer than approximately 500m due to the gains from hybrid ARQ with packet combining, slow TPC, and proportional fairness based channel-dependent scheduling.

Wireless rake-receiver using adaptive filter with a family of partial update algorithms in noise cancellation applications

NASA Astrophysics Data System (ADS)

Fayadh, Rashid A.; Malek, F.; Fadhil, Hilal A.; Aldhaibani, Jaafar A.; Salman, M. K.; Abdullah, Farah Salwani

2015-05-01

For high data rate propagation in wireless ultra-wideband (UWB) communication systems, the inter-symbol interference (ISI), multiple-access interference (MAI), and multiple-users interference (MUI) are influencing the performance of the wireless systems. In this paper, the rake-receiver was presented with the spread signal by direct sequence spread spectrum (DS-SS) technique. The adaptive rake-receiver structure was shown with adjusting the receiver tap weights using least mean squares (LMS), normalized least mean squares (NLMS), and affine projection algorithms (APA) to support the weak signals by noise cancellation and mitigate the interferences. To minimize the data convergence speed and to reduce the computational complexity by the previous algorithms, a well-known approach of partial-updates (PU) adaptive filters were employed with algorithms, such as sequential-partial, periodic-partial, M-max-partial, and selective-partial updates (SPU) in the proposed system. The simulation results of bit error rate (BER) versus signal-to-noise ratio (SNR) are illustrated to show the performance of partial-update algorithms that have nearly comparable performance with the full update adaptive filters. Furthermore, the SPU-partial has closed performance to the full-NLMS and full-APA while the M-max-partial has closed performance to the full-LMS updates algorithms.

On the Benefits of Creeping Wave Antennas in Reducing Interference Between Neighboring Wireless Body Area Networks.

PubMed

Tsouri, Gill R; Zambito, Stephanie R; Venkataraman, Jayanti

2017-02-01

We consider the on-body, off-body, and body-to-body channels in wireless body area networks utilizing creeping wave antennas. Experimental setups are used to gather measurements in the 2.4 GHz band with body area networks operating in an office environment. Data packets providing received signal strength indicators are used to assess the performance of the creeping wave antenna in reducing interference at a neighboring on-body access point while supporting reliable on-body communications. Results demonstrate that creeping wave antennas provide reliable on-body communications while significantly reducing inter-network interference; the inter-network interference is shown to be 10 dB weaker than the on-body signal. In addition, the inter-network interference when both networks utilize creeping wave antennas is shown to be 3 dB weaker than the interference when monopole antennas are used.

HYBRID SILICON-ON-SAPPHIRE/SCALED CMOS INTERFERENCE MITIGATION FRONT END BASED ON SIMULTANEOUS NOISE CANCELLATION, ACTIVE-INTERFERENCE CANCELLATION AND N-PATH-MIXER FILTERING

DTIC Science & Technology

2017-04-01

INTERFERENCE-CANCELLATION AND N-PATH-MIXER FILTERING Harish Krishnaswamy, Negar Reiskarimian, and Linxiao Zhang Columbia University APRIL 2017 Final...INTERFERENCE-CANCELLATION AND N- PATH-MIXER FILTERING 5a. CONTRACT NUMBER FA8650-14-1-7414 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61101E/62716E 6...techniques for developing interference mitigation technology (IMT) enabling frequency-agile, reconfigurable filter -less receivers. Wideband noise

Coexistence Analysis of Adjacent Long Term Evolution (LTE) Systems

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

Aulama, Mohannad M.; Olama, Mohammed M

As the licensing and deployment of Long term evolution (LTE) systems are ramping up, the study of coexistence of LTE systems is an essential topic in civil and military applications. In this paper, we present a coexistence study of adjacent LTE systems aiming at evaluating the effect of inter-system interference on system capacity and performance as a function of some of the most common mitigation techniques: frequency guard band, base station (BS) antenna coupling loss, and user equipment (UE) antenna spacing. A system model is constructed for two collocated macro LTE networks. The developed model takes into consideration the RFmore » propagation environment, power control scheme, and adjacent channel interference. Coexistence studies are performed for a different combination of time/frequency division duplex (TDD/FDD) systems under three different guard-bands of 0MHz, 5MHz, and 10MHz. Numerical results are presented to advice the minimum frequency guard band, BS coupling loss, and UE antenna isolation required for a healthy system operation.« less

OFDM Coupled Compressive Sensing Algorithm for Stepped-Frequency Ground Penetrating Radar

DTIC Science & Technology

2014-10-01

These frequencies are combined in such a way to achieve orthogonality between the carrier frequencies, while mitigating any interference between...in such a way to achieve orthogonality between the carrier frequencies, while mitigating any interference between said frequencies. In CS, a signal...frequency tones is mitigated . Orthogonality requires that the sub-bands are spaced at = is the OFDM symbol period, and k is any

Fast interaction of atoms with crystal surfaces: coherent lighting

NASA Astrophysics Data System (ADS)

Gravielle, M. S.

2017-11-01

Quantum coherence of incident waves results essential for the observation of interference patterns in grazing incidence fast atom diffraction (FAD). In this work we investigate the influence of the impact energy and projectile mass on the transversal length of the surface area that is coherently illuminated by the atomic beam, after passing through a collimating aperture. Such a transversal coherence length controls the general features of the interference structures, being here derived by means of the Van Cittert-Zernike theorem. The coherence length is then used to build the initial coherent wave packet within the Surface Initial Value Representation (SIVR) approximation. The SIVR approach is applied to fast He and Ne atoms impinging grazingly on a LiF(001) surface along a low-indexed crystallographic direction. We found that with the same collimating setup, by varying the impact energy we would be able to control the interference mechanism that prevails in FAD patterns, switching between inter-cell and unit-cell interferences. These findings are relevant to use FAD spectra adequately as a surface analysis tool, as well as to choose the appropriate collimating scheme for the observation of interference effects in a given collision system.

Interference Mitigation Schemes for Wireless Body Area Sensor Networks: A Comparative Survey

PubMed Central

Le, Thien T.T.; Moh, Sangman

2015-01-01

A wireless body area sensor network (WBASN) consists of a coordinator and multiple sensors to monitor the biological signals and functions of the human body. This exciting area has motivated new research and standardization processes, especially in the area of WBASN performance and reliability. In scenarios of mobility or overlapped WBASNs, system performance will be significantly degraded because of unstable signal integrity. Hence, it is necessary to consider interference mitigation in the design. This survey presents a comparative review of interference mitigation schemes in WBASNs. Further, we show that current solutions are limited in reaching satisfactory performance, and thus, more advanced solutions should be developed in the future. PMID:26110407

Indoor visible light communication with smart lighting technology

NASA Astrophysics Data System (ADS)

Das Barman, Abhirup; Halder, Alak

2017-02-01

An indoor visible-light communication performance is investigated utilizing energy efficient white light by 2D LED arrays. Enabled by recent advances in LED technology, IEEE 802.15.7 standardizes high-data-rate visible light communication and advocates for colour shift keying (CSK) modulation to overcome flicker and to support dimming. Voronoi segmentation is employed for decoding N-CSK constellation which has superior performance compared to other existing decoding methods. The two chief performance degrading effects of inter-symbol interference and LED nonlinearity is jointly mitigated using LMS post equalization at the receiver which improves the symbol error rate performance and increases field of view of the receiver. It is found that LMS post equalization symbol at 250MHz offers 7dB SNR improvement at SER10-6

Estimation and uncertainty analysis of dose response in an inter-laboratory experiment

NASA Astrophysics Data System (ADS)

Toman, Blaza; Rösslein, Matthias; Elliott, John T.; Petersen, Elijah J.

2016-02-01

An inter-laboratory experiment for the evaluation of toxic effects of NH2-polystyrene nanoparticles on living human cancer cells was performed with five participating laboratories. Previously published results from nanocytoxicity assays are often contradictory, mostly due to challenges related to producing a reliable cytotoxicity assay protocol for use with nanomaterials. Specific challenges include reproducibility preparing nanoparticle dispersions, biological variability from testing living cell lines, and the potential for nano-related interference effects. In this experiment, such challenges were addressed by developing a detailed experimental protocol and using a specially designed 96-well plate layout which incorporated a range of control measurements to assess multiple factors such as nanomaterial interference, pipetting accuracy, cell seeding density, and instrument performance. Detailed data analysis of these control measurements showed that good control of the experiments was attained by all participants in most cases. The main measurement objective of the study was the estimation of a dose response relationship between concentration of the nanoparticles and metabolic activity of the living cells, under several experimental conditions. The dose curve estimation was achieved by imbedding a three parameter logistic curve in a three level Bayesian hierarchical model, accounting for uncertainty due to all known experimental conditions as well as between laboratory variability in a top-down manner. Computation was performed using Markov Chain Monte Carlo methods. The fit of the model was evaluated using Bayesian posterior predictive probabilities and found to be satisfactory.

Cognitive interference can be mitigated by consonant music and facilitated by dissonant music.

PubMed

Masataka, Nobuo; Perlovsky, Leonid

2013-01-01

Debates on the origins of consonance and dissonance in music have a long history. While some scientists argue that consonance judgments are an acquired competence based on exposure to the musical-system-specific knowledge of a particular culture, others favor a biological explanation for the observed preference for consonance. Here we provide experimental confirmation that this preference plays an adaptive role in human cognition: it reduces cognitive interference. The results of our experiment reveal that exposure to a Mozart minuet mitigates interference, whereas, conversely, when the music is modified to consist of mostly dissonant intervals the interference effect is intensified.

Cognitive interference can be mitigated by consonant music and facilitated by dissonant music

PubMed Central

Masataka, Nobuo; Perlovsky, Leonid

2013-01-01

Debates on the origins of consonance and dissonance in music have a long history. While some scientists argue that consonance judgments are an acquired competence based on exposure to the musical-system-specific knowledge of a particular culture, others favor a biological explanation for the observed preference for consonance. Here we provide experimental confirmation that this preference plays an adaptive role in human cognition: it reduces cognitive interference. The results of our experiment reveal that exposure to a Mozart minuet mitigates interference, whereas, conversely, when the music is modified to consist of mostly dissonant intervals the interference effect is intensified. PMID:23778307

Impulsive interference in communication channels and its mitigation by SPART and other nonlinear filters

NASA Astrophysics Data System (ADS)

Nikitin, Alexei V.; Epard, Marc; Lancaster, John B.; Lutes, Robert L.; Shumaker, Eric A.

2012-12-01

A strong digital communication transmitter in close physical proximity to a receiver of a weak signal can noticeably interfere with the latter even when the respective channels are tens or hundreds of megahertz apart. When time domain observations are made in the signal chain of the receiver between the first mixer and the baseband, this interference is likely to appear impulsive. The impulsive nature of this interference provides an opportunity to reduce its power by nonlinear filtering, improving the quality of the receiver channel. This article describes the mitigation, by a particular nonlinear filter, of the impulsive out-of-band (OOB) interference induced in High Speed Downlink Packet Access (HSDPA) by WiFi transmissions, protocols which coexist in many 3G smartphones and mobile hotspots. Our measurements show a decrease in the maximum error-free bit rate of a 1.95 GHz HSDPA receiver caused by the impulsive interference from an OOB 2.4 GHz WiFi transmission, sometimes down to a small fraction of the rate observed in the absence of the interference. We apply a nonlinear SPART filter to recover a noticeable portion of the lost rate and maintain an error-free connection under much higher levels of the WiFi interference than a receiver that does not contain such a filter. These measurements support our wider investigation of OOB interference resulting from digital modulation, which appears impulsive in a receiver, and its mitigation by nonlinear filters.

Dissociating Interference-Control Processes between Memory and Response

ERIC Educational Resources Information Center

Bissett, Patrick G.; Nee, Derek Evan; Jonides, John

2009-01-01

The ability to mitigate interference is of central importance to cognition. Previous research has provided conflicting accounts about whether operations that resolve interference are singular in character or form a family of functions. Here, the authors examined the relationship between interference-resolution processes acting on working memory…

Low-Complexity Noncoherent Signal Detection for Nanoscale Molecular Communications.

PubMed

Li, Bin; Sun, Mengwei; Wang, Siyi; Guo, Weisi; Zhao, Chenglin

2016-01-01

Nanoscale molecular communication is a viable way of exchanging information between nanomachines. In this investigation, a low-complexity and noncoherent signal detection technique is proposed to mitigate the inter-symbol-interference (ISI) and additive noise. In contrast to existing coherent detection methods of high complexity, the proposed noncoherent signal detector is more practical when the channel conditions are hard to acquire accurately or hidden from the receiver. The proposed scheme employs the molecular concentration difference to detect the ISI corrupted signals and we demonstrate that it can suppress the ISI effectively. The difference in molecular concentration is a stable characteristic, irrespective of the diffusion channel conditions. In terms of complexity, by excluding matrix operations or likelihood calculations, the new detection scheme is particularly suitable for nanoscale molecular communication systems with a small energy budget or limited computation resource.

A New Reassigned Spectrogram Method in Interference Detection for GNSS Receivers.

PubMed

Sun, Kewen; Jin, Tian; Yang, Dongkai

2015-09-02

Interference detection is very important for Global Navigation Satellite System (GNSS) receivers. Current work on interference detection in GNSS receivers has mainly focused on time-frequency (TF) analysis techniques, such as spectrogram and Wigner-Ville distribution (WVD), where the spectrogram approach presents the TF resolution trade-off problem, since the analysis window is used, and the WVD method suffers from the very serious cross-term problem, due to its quadratic TF distribution nature. In order to solve the cross-term problem and to preserve good TF resolution in the TF plane at the same time, in this paper, a new TF distribution by using a reassigned spectrogram has been proposed in interference detection for GNSS receivers. This proposed reassigned spectrogram method efficiently combines the elimination of the cross-term provided by the spectrogram itself according to its inherent nature and the improvement of the TF aggregation property achieved by the reassignment method. Moreover, a notch filter has been adopted in interference mitigation for GNSS receivers, where receiver operating characteristics (ROCs) are used as metrics for the characterization of interference mitigation performance. The proposed interference detection method by using a reassigned spectrogram is evaluated by experiments on GPS L1 signals in the disturbing scenarios in comparison to the state-of-the-art TF analysis approaches. The analysis results show that the proposed interference detection technique effectively overcomes the cross-term problem and also keeps good TF localization properties, which has been proven to be valid and effective to enhance the interference Sensors 2015, 15 22168 detection performance; in addition, the adoption of the notch filter in interference mitigation has shown a significant acquisition performance improvement in terms of ROC curves for GNSS receivers in jamming environments.

A New Reassigned Spectrogram Method in Interference Detection for GNSS Receivers

PubMed Central

Sun, Kewen; Jin, Tian; Yang, Dongkai

2015-01-01

Interference detection is very important for Global Navigation Satellite System (GNSS) receivers. Current work on interference detection in GNSS receivers has mainly focused on time-frequency (TF) analysis techniques, such as spectrogram and Wigner–Ville distribution (WVD), where the spectrogram approach presents the TF resolution trade-off problem, since the analysis window is used, and the WVD method suffers from the very serious cross-term problem, due to its quadratic TF distribution nature. In order to solve the cross-term problem and to preserve good TF resolution in the TF plane at the same time, in this paper, a new TF distribution by using a reassigned spectrogram has been proposed in interference detection for GNSS receivers. This proposed reassigned spectrogram method efficiently combines the elimination of the cross-term provided by the spectrogram itself according to its inherent nature and the improvement of the TF aggregation property achieved by the reassignment method. Moreover, a notch filter has been adopted in interference mitigation for GNSS receivers, where receiver operating characteristics (ROCs) are used as metrics for the characterization of interference mitigation performance. The proposed interference detection method by using a reassigned spectrogram is evaluated by experiments on GPS L1 signals in the disturbing scenarios in comparison to the state-of-the-art TF analysis approaches. The analysis results show that the proposed interference detection technique effectively overcomes the cross-term problem and also keeps good TF localization properties, which has been proven to be valid and effective to enhance the interference detection performance; in addition, the adoption of the notch filter in interference mitigation has shown a significant acquisition performance improvement in terms of ROC curves for GNSS receivers in jamming environments. PMID:26364637

Link Scheduling Algorithm with Interference Prediction for Multiple Mobile WBANs

PubMed Central

Le, Thien T. T.

2017-01-01

As wireless body area networks (WBANs) become a key element in electronic healthcare (e-healthcare) systems, the coexistence of multiple mobile WBANs is becoming an issue. The network performance is negatively affected by the unpredictable movement of the human body. In such an environment, inter-WBAN interference can be caused by the overlapping transmission range of nearby WBANs. We propose a link scheduling algorithm with interference prediction (LSIP) for multiple mobile WBANs, which allows multiple mobile WBANs to transmit at the same time without causing inter-WBAN interference. In the LSIP, a superframe includes the contention access phase using carrier sense multiple access with collision avoidance (CSMA/CA) and the scheduled phase using time division multiple access (TDMA) for non-interfering nodes and interfering nodes, respectively. For interference prediction, we define a parameter called interference duration as the duration during which disparate WBANs interfere with each other. The Bayesian model is used to estimate and classify the interference using a signal to interference plus noise ratio (SINR) and the number of neighboring WBANs. The simulation results show that the proposed LSIP algorithm improves the packet delivery ratio and throughput significantly with acceptable delay. PMID:28956827

A review of fault tolerant control strategies applied to proton exchange membrane fuel cell systems

NASA Astrophysics Data System (ADS)

Dijoux, Etienne; Steiner, Nadia Yousfi; Benne, Michel; Péra, Marie-Cécile; Pérez, Brigitte Grondin

2017-08-01

Fuel cells are powerful systems for power generation. They have a good efficiency and do not generate greenhouse gases. This technology involves a lot of scientific fields, which leads to the appearance of strongly inter-dependent parameters. This makes the system particularly hard to control and increases fault's occurrence frequency. These two issues call for the necessity to maintain the system performance at the expected level, even in faulty operating conditions. It is called "fault tolerant control" (FTC). The present paper aims to give the state of the art of FTC applied to the proton exchange membrane fuel cell (PEMFC). The FTC approach is composed of two parts. First, a diagnosis part allows the identification and the isolation of a fault; it requires a good a priori knowledge of all the possible faults. Then, a control part allows an optimal control strategy to find the best operating point to recover/mitigate the fault; it requires the knowledge of the degradation phenomena and their mitigation strategies.

Coping with Radio Frequency Interference

NASA Astrophysics Data System (ADS)

Lewis, B. M.

2009-01-01

The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

The Myth of Spatial Reuse with Directional Antennas in Indoor Wireless Networks

NASA Astrophysics Data System (ADS)

Lakshmanan, Sriram; Sundaresan, Karthikeyan; Rangarajan, Sampath; Sivakumar, Raghupathy

Interference among co-channel users is a fundamental problem in wireless networks, which prevents nearby links from operating concurrently. Directional antennas allow the radiation patterns of wireless transmitters to be shaped to form directed beams. Conventionally, such beams are assumed to improve the spatial reuse (i.e. concurrency) in indoor wireless networks. In this paper, we use experiments in an indoor office setting of Wifi Access points equipped with directional antennas, to study their potential for interference mitigation and spatial reuse. In contrast to conventional wisdom, we observe that the interference mitigation benefits of directional antennas are minimal. On analyzing our experimental traces we observe that directional links do not reduce interference to nearby links due to the lack of signal confinement due to indoor multipath fading. We then use the insights derived from our study to develop an alternative approach that provides better interference reduction in indoor networks compared to directional links.

An inter-lighting interference cancellation scheme for MISO-VLC systems

NASA Astrophysics Data System (ADS)

Kim, Kyuntak; Lee, Kyujin; Lee, Kyesan

2017-08-01

In this paper, we propose an inter-lighting interference cancellation (ILIC) scheme to reduce the interference between adjacent light-emitting diodes (LEDs) and enhance the transmission capacity of multiple-input-single-output (MISO)-visible light communication (VLC) systems. In indoor environments, multiple LEDs have normally been used as lighting sources, allowing the design of MISO-VLC systems. To enhance the transmission capacity, different data should be simultaneously transmitted from each LED; however, that can lead to interference between adjacent LEDs. In that case, relatively low-received power signals are subjected to large interference because wireless optical systems generally use intensity modulation and direct detection. Thus, only the signal with the highest received power can be detected, while the other received signals cannot be detected. To solve this problem, we propose the ILIC scheme for MISO-VLC systems. The proposed scheme preferentially detects the highest received power signal, and this signal is referred as interference signal by an interference component generator. Then, relatively low-received power signal can be detected by cancelling the interference signal from the total received signals. Therefore, the performance of the proposed scheme can improve the total average bit error rate and throughput of a MISO-VLC system.

Maximizing mitigation benefits-making a difference with strategic inter-resource agency planning : year two technical report.

DOT National Transportation Integrated Search

2014-11-01

The objective of this research project is to assess current mitigation policies and practices in comparison to : resource agency objectives and to identify mitigation strategies and priorities that provide greater cost-benefit potential and implement...

Maximizing mitigation benefits-making a difference with strategic inter-resource agency planning : year one technical report.

DOT National Transportation Integrated Search

2014-04-01

The objective of this research project is to assess current mitigation policies and practices in comparison to : resource agency objectives, and identify mitigation strategies and priorities that provide greater cost-benefit : potential and implement...

Microbial interference mitigates Meloidogyne incognita mediated oxidative stress and augments bacoside content in Bacopa monnieri L.

PubMed

Gupta, Rupali; Singh, Akanksha; Ajayakumar, P V; Pandey, Rakesh

2017-06-01

Microbial interference plays an imperative role in plant development and response to various stresses. However, its involvement in mitigation of oxidative stress generated by plant parasitic nematode in plants remains elusive. In the present investigation, the efficacy of microbe's viz., Chitiniphilus sp. MTN22 and Streptomyces sp. MTN14 single and in combinations was examined to mitigate oxidative stress generated by M. incognita in medicinal plant, Bacopa monnieri. Microbial combination with and without pathogen also enhanced the growth parameters along with secondary metabolites (bacoside) of B. monnieri than the pathogen inoculated control. The study showed that initially the production of hydrogen peroxide (H 2 O 2 ) was higher in dual microbes infected with pathogen which further declined over M. incognita inoculated control plants. Superoxide dismutase and free radical scavenging activity were also highest in the same treatment which was linearly related with least lipid peroxidation and root gall formation in B. monnieri under the biotic stress. Microscopic visualization of total reactive oxygen species (ROS), H 2 O 2 , superoxide radical and programmed cell death in host plant further extended our knowledge and corroborated well with the above findings. Furthermore, scanning electron microscopy confirmed good microbial colonization on the host root surface around nematode penetration sites in plants treated with dual microbes under pathogenic stress. The findings offer novel insight into the mechanism adopted by the synergistic microbial strains in mitigating oxidative stress and simultaneously stimulating bacoside production under pathogenic stress. Copyright © 2017 Elsevier GmbH. All rights reserved.

Declarative memory: sleep protects new memories from interference.

PubMed

Norman, Kenneth A

2006-08-08

Interference is one of the most fundamental phenomena in memory research: acquiring new memories causes forgetting of other, related memories. A new study shows that sleep, interposed between learning episodes, can mitigate the extent to which new (post-sleep) learning interferes with recall of previously acquired knowledge.

IFT&E Industry Report Wind Turbine-Radar Interference Test Summary.

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

Karlson, Benjamin; LeBlanc, Bruce Philip.; Minster, David G

2014-10-01

Wind turbines have grown in size and capacity with today's average turbine having a power capacity of around 1.9 MW, reaching to heights of over 495 feet from ground to blade tip, and operating with speeds at the tip of the blade up to 200 knots. When these machines are installed within the line-of-sight of a radar system, they can cause significant clutter and interference, detrimentally impacting the primary surveillance radar (PSR) performance. The Massachusetts Institute of Technology's Lincoln Laboratory (MIT LL) and Sandia National Laboratories (SNL) were co-funded to conduct field tests and evaluations over two years in ordermore » to: I. Characterize the impact of wind turbines on existing Program-of-Record (POR) air surveillance radars; II. Assess near-term technologies proposed by industry that have the potential to mitigate the interference from wind turbines on radar systems; and III. Collect data and increase technical understanding of interference issues to advance development of long-term mitigation strategies. MIT LL and SNL managed the tests and evaluated resulting data from three flight campaigns to test eight mitigation technologies on terminal (short) and long-range (60 nmi and 250 nmi) radar systems. Combined across the three flight campaigns, more than 460 of hours of flight time were logged. This paper summarizes the Interagency Field Test & Evaluation (IFT&E) program and publicly- available results from the tests. It will also discuss the current wind turbine-radar interference evaluation process within the government and a proposed process to deploy mitigation technologies.« less

Performance of the split-symbol moments SNR estimator in the presence of inter-symbol interference

NASA Technical Reports Server (NTRS)

Shah, B.; Hinedi, S.

1989-01-01

The Split-Symbol Moments Estimator (SSME) is an algorithm that is designed to estimate symbol signal-to-noise ratio (SNR) in the presence of additive white Gaussian noise (AWGN). The performance of the SSME algorithm in band-limited channels is examined. The effects of the resulting inter-symbol interference (ISI) are quantified. All results obtained are in closed form and can be easily evaluated numerically for performance prediction purposes. Furthermore, they are validated through digital simulations.

Combining DCQGMP-Based Sparse Decomposition and MPDR Beamformer for Multi-Type Interferences Mitigation for GNSS Receivers.

PubMed

Guo, Qiang; Qi, Liangang

2017-04-10

In the coexistence of multiple types of interfering signals, the performance of interference suppression methods based on time and frequency domains is degraded seriously, and the technique using an antenna array requires a large enough size and huge hardware costs. To combat multi-type interferences better for GNSS receivers, this paper proposes a cascaded multi-type interferences mitigation method combining improved double chain quantum genetic matching pursuit (DCQGMP)-based sparse decomposition and an MPDR beamformer. The key idea behind the proposed method is that the multiple types of interfering signals can be excised by taking advantage of their sparse features in different domains. In the first stage, the single-tone (multi-tone) and linear chirp interfering signals are canceled by sparse decomposition according to their sparsity in the over-complete dictionary. In order to improve the timeliness of matching pursuit (MP)-based sparse decomposition, a DCQGMP is introduced by combining an improved double chain quantum genetic algorithm (DCQGA) and the MP algorithm, and the DCQGMP algorithm is extended to handle the multi-channel signals according to the correlation among the signals in different channels. In the second stage, the minimum power distortionless response (MPDR) beamformer is utilized to nullify the residuary interferences (e.g., wideband Gaussian noise interferences). Several simulation results show that the proposed method can not only improve the interference mitigation degree of freedom (DoF) of the array antenna, but also effectively deal with the interference arriving from the same direction with the GNSS signal, which can be sparse represented in the over-complete dictionary. Moreover, it does not bring serious distortions into the navigation signal.

Combining DCQGMP-Based Sparse Decomposition and MPDR Beamformer for Multi-Type Interferences Mitigation for GNSS Receivers

PubMed Central

Guo, Qiang; Qi, Liangang

2017-01-01

In the coexistence of multiple types of interfering signals, the performance of interference suppression methods based on time and frequency domains is degraded seriously, and the technique using an antenna array requires a large enough size and huge hardware costs. To combat multi-type interferences better for GNSS receivers, this paper proposes a cascaded multi-type interferences mitigation method combining improved double chain quantum genetic matching pursuit (DCQGMP)-based sparse decomposition and an MPDR beamformer. The key idea behind the proposed method is that the multiple types of interfering signals can be excised by taking advantage of their sparse features in different domains. In the first stage, the single-tone (multi-tone) and linear chirp interfering signals are canceled by sparse decomposition according to their sparsity in the over-complete dictionary. In order to improve the timeliness of matching pursuit (MP)-based sparse decomposition, a DCQGMP is introduced by combining an improved double chain quantum genetic algorithm (DCQGA) and the MP algorithm, and the DCQGMP algorithm is extended to handle the multi-channel signals according to the correlation among the signals in different channels. In the second stage, the minimum power distortionless response (MPDR) beamformer is utilized to nullify the residuary interferences (e.g., wideband Gaussian noise interferences). Several simulation results show that the proposed method can not only improve the interference mitigation degree of freedom (DoF) of the array antenna, but also effectively deal with the interference arriving from the same direction with the GNSS signal, which can be sparse represented in the over-complete dictionary. Moreover, it does not bring serious distortions into the navigation signal. PMID:28394290

Out-of-band and adjacent-channel interference reduction by analog nonlinear filters

NASA Astrophysics Data System (ADS)

Nikitin, Alexei V.; Davidchack, Ruslan L.; Smith, Jeffrey E.

2015-12-01

In a perfect world, we would have `brick wall' filters, no-distortion amplifiers and mixers, and well-coordinated spectrum operations. The real world, however, is prone to various types of unintentional and intentional interference of technogenic (man-made) origin that can disrupt critical communication systems. In this paper, we introduce a methodology for mitigating technogenic interference in communication channels by analog nonlinear filters, with an emphasis on the mitigation of out-of-band and adjacent-channel interference. Interference induced in a communications receiver by external transmitters can be viewed as wide-band non-Gaussian noise affecting a narrower-band signal of interest. This noise may contain a strong component within the receiver passband, which may dominate over the thermal noise. While the total wide-band interference seen by the receiver may or may not be impulsive, we demonstrate that the interfering component due to power emitted by the transmitter into the receiver channel is likely to appear impulsive under a wide range of conditions. We give an example of mechanisms of impulsive interference in digital communication systems resulting from the nonsmooth nature of any physically realizable modulation scheme for transmission of a digital (discontinuous) message. We show that impulsive interference can be effectively mitigated by nonlinear differential limiters (NDLs). An NDL can be configured to behave linearly when the input signal does not contain outliers. When outliers are encountered, the nonlinear response of the NDL limits the magnitude of the respective outliers in the output signal. The signal quality is improved in excess of that achievable by the respective linear filter, increasing the capacity of a communications channel. The behavior of an NDL, and its degree of nonlinearity, is controlled by a single parameter in a manner that enables significantly better overall suppression of the noise-containing impulsive components compared to the respective linear filter. Adaptive configurations of NDLs are similarly controlled by a single parameter and are suitable for improving quality of nonstationary signals under time-varying noise conditions. NDLs are designed to be fully compatible with existing linear devices and systems and to be used as an enhancement, or as a low-cost alternative, to the state-of-art interference mitigation methods.

Goal motives and multiple-goal striving in sport and academia: A person-centered investigation of goal motives and inter-goal relations.

PubMed

Healy, Laura C; Ntoumanis, Nikos; Duda, Joan L

2016-12-01

This investigation extended the goal striving literature by examining motives for two goals being pursued simultaneously. Grounded in self-determination theory, we examined how student-athletes' motives for their sporting and academic goals were associated with inter-goal facilitation and interference. Cross-sectional survey. UK university student-athletes (n=204) identified their most important sporting and academic goals. They then rated their extrinsic, introjected, identified and intrinsic motives for these goals and completed questionnaires assessing inter-goal facilitation and interference. Using a person-centered approach via latent profile analysis, we identified three distinct profiles of goal motives. Auxiliary analyses showed that the profile with high identified motives for both goals reported greater inter-goal facilitation. Extending the previous literature, the findings demonstrate the benefits of autonomous motives when simultaneously pursing goals in sport and academia. Copyright © 2016. Published by Elsevier Ltd.

Performance Enhancement of MC-CDMA System through Novel Sensitive Bit Algorithm Aided Turbo Multi User Detection

PubMed Central

Kumaravel, Rasadurai; Narayanaswamy, Kumaratharan

2015-01-01

Multi carrier code division multiple access (MC-CDMA) system is a promising multi carrier modulation (MCM) technique for high data rate wireless communication over frequency selective fading channels. MC-CDMA system is a combination of code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). The OFDM parts reduce multipath fading and inter symbol interference (ISI) and the CDMA part increases spectrum utilization. Advantages of this technique are its robustness in case of multipath propagation and improve security with the minimize ISI. Nevertheless, due to the loss of orthogonality at the receiver in a mobile environment, the multiple access interference (MAI) appears. The MAI is one of the factors that degrade the bit error rate (BER) performance of MC-CDMA system. The multiuser detection (MUD) and turbo coding are the two dominant techniques for enhancing the performance of the MC-CDMA systems in terms of BER as a solution of overcome to MAI effects. In this paper a low complexity iterative soft sensitive bits algorithm (SBA) aided logarithmic-Maximum a-Posteriori algorithm (Log MAP) based turbo MUD is proposed. Simulation results show that the proposed method provides better BER performance with low complexity decoding, by mitigating the detrimental effects of MAI. PMID:25714917

RFI Mitigation and Testing Employed at GGAO for NASA's Space Geodesy Project (SGP)

NASA Technical Reports Server (NTRS)

Hilliard, Lawrence M.; Rajagopalan, Ganesh; Stevenson, Thomas; Turner, Charles; Bulcha, Berhanu

2017-01-01

Radio Frequency Interference (RFI) Mitigation at Goddard Geophysical and Astronomical Observatory (GGAO) has been addressed in three different ways by NASA's Space Geodesy Project (SGP); masks, blockers, and filters. All of these techniques will be employed at the GGAO, to mitigate the RFI consequences to the Very Long Baseline Interferometer.

Base Station Placement Algorithm for Large-Scale LTE Heterogeneous Networks.

PubMed

Lee, Seungseob; Lee, SuKyoung; Kim, Kyungsoo; Kim, Yoon Hyuk

2015-01-01

Data traffic demands in cellular networks today are increasing at an exponential rate, giving rise to the development of heterogeneous networks (HetNets), in which small cells complement traditional macro cells by extending coverage to indoor areas. However, the deployment of small cells as parts of HetNets creates a key challenge for operators' careful network planning. In particular, massive and unplanned deployment of base stations can cause high interference, resulting in highly degrading network performance. Although different mathematical modeling and optimization methods have been used to approach various problems related to this issue, most traditional network planning models are ill-equipped to deal with HetNet-specific characteristics due to their focus on classical cellular network designs. Furthermore, increased wireless data demands have driven mobile operators to roll out large-scale networks of small long term evolution (LTE) cells. Therefore, in this paper, we aim to derive an optimum network planning algorithm for large-scale LTE HetNets. Recently, attempts have been made to apply evolutionary algorithms (EAs) to the field of radio network planning, since they are characterized as global optimization methods. Yet, EA performance often deteriorates rapidly with the growth of search space dimensionality. To overcome this limitation when designing optimum network deployments for large-scale LTE HetNets, we attempt to decompose the problem and tackle its subcomponents individually. Particularly noting that some HetNet cells have strong correlations due to inter-cell interference, we propose a correlation grouping approach in which cells are grouped together according to their mutual interference. Both the simulation and analytical results indicate that the proposed solution outperforms the random-grouping based EA as well as an EA that detects interacting variables by monitoring the changes in the objective function algorithm in terms of system throughput performance.

Schema benefit vs. proactive interference: Contradicting behavioral outcomes and coexisting neural patterns.

PubMed

Oren, Noga; Shapira-Lichter, Irit; Lerner, Yulia; Tarrasch, Ricardo; Hendler, Talma; Giladi, Nir; Ash, Elissa L

2017-09-01

Prior knowledge can either assist or hinder the ability to learn new information. These contradicting behavioral outcomes, referred to as schema benefit and proactive interference respectively, have been studied separately. Here we examined whether the known neural correlates of each process coexist, and how they are influenced by attentional loading and aging. To this end we used an fMRI task that affected both processes simultaneously by presenting pairs of related short movies in succession. The first movie of each pair provided context for the second movie, which could evoke schema benefit and/or proactive interference. Inclusion of an easy or hard secondary task performed during encoding of the movies, as well as testing both younger (22-35y) and older (65-79y) adults, allowed examining the effect of attentional load and older age on the neural patterns associated with context. Analyses focused on three predefined regions and examined how their inter-subject correlation (inter-SC) and functional connectivity (FC) with the hippocampi changed between the first and second movie. The results in the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC) matched and expanded previous findings: higher inter-SC and lower FC were observed during the second compared to the first movie; yet the differentiation between the first and second movies in these regions was attenuated under high attentional load, pointing to dependency on attentional resources. Instead, at high load there was a significant context effect in the FC of the left ventrolateral prefrontal cortex (vlPFC), and greater FC in the second movie was related to greater proactive interference. Further, older adults showed context effect in the PCC and vlPFC. Intriguingly, older adults with inter-SC mPFC patterns similar to younger adults exhibited schema benefit in our task, while those with inter-SC PCC patterns similar to younger adults showed proactive interference in an independent task. The brain-behavior relationships corroborate the functional significance of these regions and indicate that the mPFC mainly contributes to schema benefit, while the left vlPFC and PCC contribute to proactive interference. Importantly, our findings show that the functions of the regions are retained throughout the lifespan and may predict the predominant behavioral outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

Role of inter-tube coupling and quantum interference on electrical transport in carbon nanotube junctions

NASA Astrophysics Data System (ADS)

Tripathy, Srijeet; Bhattacharyya, Tarun Kanti

2016-09-01

Due to excellent transport properties, Carbon nanotubes (CNTs) show a lot of promise in sensor and interconnect technology. However, recent studies indicate that the conductance in CNT/CNT junctions are strongly affected by the morphology and orientation between the tubes. For proper utilization of such junctions in the development of CNT based technology, it is essential to study the electronic properties of such junctions. This work presents a theoretical study of the electrical transport properties of metallic Carbon nanotube homo-junctions. The study focuses on discerning the role of inter-tube interactions, quantum interference and scattering on the transport properties on junctions between identical tubes. The electronic structure and transport calculations are conducted with an Extended Hückel Theory-Non Equilibrium Green's Function based model. The calculations indicate conductance to be varying with a changing crossing angle, with maximum conductance corresponding to lattice registry, i.e. parallel configuration between the two tubes. Further calculations for such parallel configurations indicate onset of short and long range oscillations in conductance with respect to changing overlap length. These oscillations are attributed to inter-tube coupling effects owing to changing π orbital overlap, carrier scattering and quantum interference of the incident, transmitted and reflected waves at the inter-tube junction.

tf_unet: Generic convolutional neural network U-Net implementation in Tensorflow

NASA Astrophysics Data System (ADS)

Akeret, Joel; Chang, Chihway; Lucchi, Aurelien; Refregier, Alexandre

2016-11-01

tf_unet mitigates radio frequency interference (RFI) signals in radio data using a special type of Convolutional Neural Network, the U-Net, that enables the classification of clean signal and RFI signatures in 2D time-ordered data acquired from a radio telescope. The code is not tied to a specific segmentation and can be used, for example, to detect radio frequency interference (RFI) in radio astronomy or galaxies and stars in widefield imaging data. This U-Net implementation can outperform classical RFI mitigation algorithms.

A New Subcarrier Allocation Strategy for MIMO-OFDMA Multicellular Networks Based on Cooperative Interference Mitigation

PubMed Central

Gkonis, Panagiotis K.; Seimeni, Maria A.; Asimakis, Nikolaos P.; Kaklamani, Dimitra I.; Venieris, Iakovos S.

2014-01-01

The goal of the study presented in this paper is to investigate the performance of a new subcarrier allocation strategy for Orthogonal Frequency Division Multiple Access (OFDMA) multicellular networks which employ Multiple Input Multiple Output (MIMO) architecture. For this reason, a hybrid system-link level simulator has been developed executing independent Monte Carlo (MC) simulations in parallel. Up to two tiers of cells around the central cell are taken into consideration and increased loading per cell. The derived results indicate that this strategy can provide up to 12% capacity gain for 16-QAM modulation and two tiers of cells around the central cell in a symmetric 2 × 2 MIMO configuration. This gain is derived when comparing the proposed strategy to the traditional approach of allocating subcarriers that maximize only the desired user's signal. PMID:24683351

Radiated Interference in Rapid Transit Systems. Volume 1. Theory and Data.

DOT National Transportation Integrated Search

1988-04-01

For the past eight years, the UMTA Office of Systems Engineering, U.S. Department of Transportation, has sponsored a program to delineate and mitigate the effects of electromagnetic interference (EMI) in rail transit operations. Work has proceeded un...

Cyber security with radio frequency interferences mitigation study for satellite systems

NASA Astrophysics Data System (ADS)

Wang, Gang; Wei, Sixiao; Chen, Genshe; Tian, Xin; Shen, Dan; Pham, Khanh; Nguyen, Tien M.; Blasch, Erik

2016-05-01

Satellite systems including the Global Navigation Satellite System (GNSS) and the satellite communications (SATCOM) system provide great convenience and utility to human life including emergency response, wide area efficient communications, and effective transportation. Elements of satellite systems incorporate technologies such as navigation with the global positioning system (GPS), satellite digital video broadcasting, and information transmission with a very small aperture terminal (VSAT), etc. The satellite systems importance is growing in prominence with end users' requirement for globally high data rate transmissions; the cost reduction of launching satellites; development of smaller sized satellites including cubesat, nanosat, picosat, and femtosat; and integrating internet services with satellite networks. However, with the promising benefits, challenges remain to fully develop secure and robust satellite systems with pervasive computing and communications. In this paper, we investigate both cyber security and radio frequency (RF) interferences mitigation for satellite systems, and demonstrate that they are not isolated. The action space for both cyber security and RF interferences are firstly summarized for satellite systems, based on which the mitigation schemes for both cyber security and RF interferences are given. A multi-layered satellite systems structure is provided with cross-layer design considering multi-path routing and channel coding, to provide great security and diversity gains for secure and robust satellite systems.

The Impact of Radio Interference on Future Radio Telescopes

NASA Astrophysics Data System (ADS)

Mitchell, Daniel A.; Robertson, Gordon J.; Sault, Robert J.

While future radio telescopes will require technological advances from the communications industry interference from sources such as satellites and mobile phones is a serious concern. In addition to the fact that the level of interference is growing constantly the increased capabilities of next generation instruments make them more prone to harmful interference. These facilities must have mechanisms to allow operation in a crowded spectrum. In this report some of the factors which may limit the effectiveness of these mechanisms are investigated. Radio astronomy is unique among other observing wavelengths in that the radiation can be fully sampled at a rate which completely specifies the electromagnetic environment. Knowledge of phases and antennae gain factors affords one the opportunity to attempt to mitigate interference from the astronomical data. At present several interference mitigation techniques have been demonstrated to be extremely effective. However the observational scales of the new facilities will push the techniques to their limits. Processes such as signal decorrelation varying antenna gain and instabilities in the primary beam will have a serious effect on some of the algorithms. In addition the sheer volume of data produced will render some techniques computationally and financially impossible.

The interruption of thyroid and interrenal and the inter-hormonal interference in fish: does it promote physiologic adaptation or maladaptation?

PubMed

Peter, Valsa S; Peter, M C Subhash

2011-12-01

Endocrines, the chief components of chemical centers which produce hormones in tune with intrinsic and extrinsic clues, create a chemical bridge between the organism and the environment. In fishes also hormones integrate and modulate many physiologic functions and its synthesis, release, biological actions and metabolic clearance are well regulated. Consequently, thyroid hormones (THs) and cortisol, the products of thyroid and interrenal axes, have been identified for their common integrative actions on metabolic and osmotic functions in fish. On the other hand, many anthropogenic chemical substances, popularly known as endocrine disrupting chemicals, have been shown to disrupt the hormone-receptor signaling pathways in a number fish species. These chemicals which are known for their ability to induce endocrine disruption particularly on thyroid and interrenals can cause malfunction or maladaptation of many vital processes which are involved in the development, growth and reproduction in fish. On the contrary, evidence is presented that the endocrine interrupting agents (EIAs) can cause interruption of thyroid and interrenals, resulting in physiologic compensatory mechanisms which can be adaptive, though such hormonal interactions are less recognized in fishes. The EIAs of physical, chemical and biological origins can specifically interrupt and modify the hormonal interactions between THs and cortisol, resulting in specific patterns of inter-hormonal interference. The physiologic analysis of these inter-hormonal interruptions during acclimation and post-acclimation to intrinsic or extrinsic EIAs reveals that combinations of anti-hormonal, pro-hormonal or stati-hormonal interference may help the fish to fine-tune their metabolic and osmotic performances as part of physiologic adaptation. This novel hypothesis on the phenomenon of inter-hormonal interference and its consequent physiologic interference during thyroid and interrenal interruption thus forms the basis of physiologic acclimation. This interfering action of TH and cortisol during hormonal interruption may subsequently promote ecological adaptation in fish as these physiologic processes ultimately favor them to survive in their hostile environment. Copyright © 2011 Elsevier Inc. All rights reserved.

Mitigation of narrowband interferences by means of a reconfigurable stepped frequency GPR system

NASA Astrophysics Data System (ADS)

Persico, Raffaele; Dei, Devis; Parrini, Filippo; Matera, Loredana

2016-08-01

This paper proposes a new technique for the mitigation of narrowband interferences by making use of an innovative stepped frequency Ground Penetrating Radar (GPR) system, based on the modulation of the integration time of the harmonic components of the signal. This can allow a good rejection of the interference signal without filtering out part of the band of the useful signal (which would involve a loss of information) and without increasing the power of the transmitted signal (which might saturate the receiver and make illegal the level of transmitted power). The price paid for this is an extension of the time needed in order to perform the measurements. We will show that this necessary drawback can be contained by making use of a prototypal reconfigurable stepped frequency GPR system.

Temporal and spatial distribution of global mitigation cost: INDCs and equity

NASA Astrophysics Data System (ADS)

Liu, Jing-Yu; Fujimori, Shinichiro; Masui, Toshihiko

2016-11-01

Each country’s Intended Nationally Determined Contribution (INDC) pledges an emission target for 2025 or 2030. Here, we evaluated the INDC inter-generational and inter-regional equity by comparing scenarios with INDC emissions target in 2030 and with an immediate emission reduction associated with a global uniform carbon price using Asian-Pacific Integrated Model/Computable General Equilibrium. Both scenarios eventually achieve 2 °C target. The results showed that, as compared with an immediate emission reduction scenario, the inter-generational equity status is not favorable for INDC scenario and the future generation suffers more from delayed mitigation. Moreover, this conclusion was robust to the wide range of inequality aversion parameter that determines discount rate. On the other hand, the INDC scenario has better inter-regional equity in the early part of the century than does the immediate emission reduction scenario in which we assume a global carbon price during the period up to 2030. However, inter-regional equity worsens later in the century. The additional emissions reduction to the INDC in 2030 would improve both inter- and inter-regional equity as compared to the current INDC. We also suggest that countries should commit to more emissions reductions in the follow-up INDC communications and that continuous consideration for low-income countries is needed for global climate change cooperation after 2030.

Reducing the harm in rail crashes : analysis of injury mechanisms and mitigation strategies

DOT National Transportation Integrated Search

2016-04-12

Twenty-three commuter and inter-city passenger train : accidents, which occurred over the past twenty years, have been : analyzed. The analysis has assessed the potential effectiveness : of various injury mitigation strategies. The strategies with th...

Radio frequency interference mitigation using deep convolutional neural networks

NASA Astrophysics Data System (ADS)

Akeret, J.; Chang, C.; Lucchi, A.; Refregier, A.

2017-01-01

We propose a novel approach for mitigating radio frequency interference (RFI) signals in radio data using the latest advances in deep learning. We employ a special type of Convolutional Neural Network, the U-Net, that enables the classification of clean signal and RFI signatures in 2D time-ordered data acquired from a radio telescope. We train and assess the performance of this network using the HIDE &SEEK radio data simulation and processing packages, as well as early Science Verification data acquired with the 7m single-dish telescope at the Bleien Observatory. We find that our U-Net implementation is showing competitive accuracy to classical RFI mitigation algorithms such as SEEK's SUMTHRESHOLD implementation. We publish our U-Net software package on GitHub under GPLv3 license.

Combined Effect of Random Transmit Power Control and Inter-Path Interference Cancellation on DS-CDMA Packet Mobile Communications

NASA Astrophysics Data System (ADS)

Kudoh, Eisuke; Ito, Haruki; Wang, Zhisen; Adachi, Fumiyuki

In mobile communication systems, high speed packet data services are demanded. In the high speed data transmission, throughput degrades severely due to severe inter-path interference (IPI). Recently, we proposed a random transmit power control (TPC) to increase the uplink throughput of DS-CDMA packet mobile communications. In this paper, we apply IPI cancellation in addition to the random TPC. We derive the numerical expression of the received signal-to-interference plus noise power ratio (SINR) and introduce IPI cancellation factor. We also derive the numerical expression of system throughput when IPI is cancelled ideally to compare with the Monte Carlo numerically evaluated system throughput. Then we evaluate, by Monte-Carlo numerical computation method, the combined effect of random TPC and IPI cancellation on the uplink throughput of DS-CDMA packet mobile communications.

33 CFR 209.340 - Laboratory investigations and materials testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... hydraulic laboratories, and to the Inter-Agency Sedimentation Project. (c) References. (1) AR 37-20. (2) AR... ordinary business channels. (3) Performance of the work will not interfere with provisions of services... with the same procedures as apply to Division Materials Laboratories. (3) Inter-Agency Sedimentation...

33 CFR 209.340 - Laboratory investigations and materials testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

... hydraulic laboratories, and to the Inter-Agency Sedimentation Project. (c) References. (1) AR 37-20. (2) AR... ordinary business channels. (3) Performance of the work will not interfere with provisions of services... with the same procedures as apply to Division Materials Laboratories. (3) Inter-Agency Sedimentation...

0-6762 : maximizing mitigation benefits-making a difference with strategic inter-resource agency planning.

DOT National Transportation Integrated Search

2014-08-01

Transportation agencies do their best to avoid : and minimize any impacts to the environment, : but some impacts are unavoidable. : Compensatory mitigation is used to offset these : unavoidable impacts to the environment. Over : $3.3 billion is spent...

The microtubule lattice and plus-end association of Drosophila Mini spindles is spatially regulated to fine-tune microtubule dynamics.

PubMed

Currie, Joshua D; Stewman, Shannon; Schimizzi, Gregory; Slep, Kevin C; Ma, Ao; Rogers, Stephen L

2011-11-01

Individual microtubules (MTs) exhibit dynamic instability, a behavior in which they cycle between phases of growth and shrinkage while the total amount of MT polymer remains constant. Dynamic instability is promoted by the conserved XMAP215/Dis1 family of microtubule-associated proteins (MAPs). In this study, we conducted an in vivo structure-function analysis of the Drosophila homologue Mini spindles (Msps). Msps exhibits EB1-dependent and spatially regulated MT localization, targeting to microtubule plus ends in the cell interior and decorating the lattice of growing and shrinking microtubules in the cell periphery. RNA interference rescue experiments revealed that the NH(2)-terminal four TOG domains of Msps function as paired units and were sufficient to promote microtubule dynamics and EB1 comet formation. We also identified TOG5 and novel inter-TOG linker motifs that are required for targeting Msps to the microtubule lattice. These novel microtubule contact sites are necessary for the interplay between the conserved TOG domains and inter-TOG MT binding that underlies the ability of Msps to promote MT dynamic instability.

Beamforming design with proactive interference cancelation in MISO interference channels

NASA Astrophysics Data System (ADS)

Li, Yang; Tian, Yafei; Yang, Chenyang

2015-12-01

In this paper, we design coordinated beamforming at base stations (BSs) to facilitate interference cancelation at users in interference networks, where each BS is equipped with multiple antennas and each user is with a single antenna. By assuming that each user can select the best decoding strategy to mitigate the interference, either canceling the interference after decoding when it is strong or treating it as noise when it is weak, we optimize the beamforming vectors that maximize the sum rate for the networks under different interference scenarios and find the solutions of beamforming with closed-form expressions. The inherent design principles are then analyzed, and the performance gain over passive interference cancelation is demonstrated through simulations in heterogeneous cellular networks.

Multibeam Interferometer Using a Photonic Crystal Fiber with Two Asymmetric Cores for Torsion, Strain and Temperature Sensing

PubMed Central

Naeem, Khurram; Kwon, Il-Bum; Chung, Youngjoo

2017-01-01

We present a fiber-optic multibeam Mach-Zehnder interferometer (m-MZI) for simultaneous multi-parameter measurement. The m-MZI is comprised of a section of photonic crystal fiber integrated with two independent cores of distinct construction and birefringence properties characterized for torsion, strain and temperature sensing. Due to the presence of small core geometry and use of a short fiber length, the sensing device demonstrates inter-modal interference in the small core alongside the dominant inter-core interference between the cores for each of the orthogonal polarizations. The output spectrum of the device is characterized by the three-beam interference model and is polarization-dependent. The two types of interferometers present in the fiber m-MZI exhibit distinct sensitivities to torsion, strain and temperature for different polarizations, and matrix coefficients allowing simultaneous measurement of the three sensing parameters are proposed in experiment. PMID:28085046

Quantum interference effect in electron tunneling through a quantum-dot-ring spin valve

PubMed Central

2011-01-01

Spin-dependent transport through a quantum-dot (QD) ring coupled to ferromagnetic leads with noncollinear magnetizations is studied theoretically. Tunneling current, current spin polarization and tunnel magnetoresistance (TMR) as functions of the bias voltage and the direct coupling strength between the two leads are analyzed by the nonequilibrium Green's function technique. It is shown that the magnitudes of these quantities are sensitive to the relative angle between the leads' magnetic moments and the quantum interference effect originated from the inter-lead coupling. We pay particular attention on the Coulomb blockade regime and find the relative current magnitudes of different magnetization angles can be reversed by tuning the inter-lead coupling strength, resulting in sign change of the TMR. For large enough inter-lead coupling strength, the current spin polarizations for parallel and antiparallel magnetic configurations will approach to unit and zero, respectively. PACS numbers: PMID:21711779

Characterizing Interference in Radio Astronomy Observations through Active and Unsupervised Learning

NASA Technical Reports Server (NTRS)

Doran, G.

2013-01-01

In the process of observing signals from astronomical sources, radio astronomers must mitigate the effects of manmade radio sources such as cell phones, satellites, aircraft, and observatory equipment. Radio frequency interference (RFI) often occurs as short bursts (< 1 ms) across a broad range of frequencies, and can be confused with signals from sources of interest such as pulsars. With ever-increasing volumes of data being produced by observatories, automated strategies are required to detect, classify, and characterize these short "transient" RFI events. We investigate an active learning approach in which an astronomer labels events that are most confusing to a classifier, minimizing the human effort required for classification. We also explore the use of unsupervised clustering techniques, which automatically group events into classes without user input. We apply these techniques to data from the Parkes Multibeam Pulsar Survey to characterize several million detected RFI events from over a thousand hours of observation.

Non-cell-autonomous driving of tumour growth supports sub-clonal heterogeneity.

PubMed

Marusyk, Andriy; Tabassum, Doris P; Altrock, Philipp M; Almendro, Vanessa; Michor, Franziska; Polyak, Kornelia

2014-10-02

Cancers arise through a process of somatic evolution that can result in substantial sub-clonal heterogeneity within tumours. The mechanisms responsible for the coexistence of distinct sub-clones and the biological consequences of this coexistence remain poorly understood. Here we used a mouse xenograft model to investigate the impact of sub-clonal heterogeneity on tumour phenotypes and the competitive expansion of individual clones. We found that tumour growth can be driven by a minor cell subpopulation, which enhances the proliferation of all cells within a tumour by overcoming environmental constraints and yet can be outcompeted by faster proliferating competitors, resulting in tumour collapse. We developed a mathematical modelling framework to identify the rules underlying the generation of intra-tumour clonal heterogeneity. We found that non-cell-autonomous driving of tumour growth, together with clonal interference, stabilizes sub-clonal heterogeneity, thereby enabling inter-clonal interactions that can lead to new phenotypic traits.

Cyclosporine-assisted adipose-derived mesenchymal stem cell therapy to mitigate acute kidney ischemia-reperfusion injury.

PubMed

Chen, Yen-Ta; Yang, Chih-Chau; Zhen, Yen-Yi; Wallace, Christopher Glenn; Yang, Jenq-Lin; Sun, Cheuk-Kwan; Tsai, Tzu-Hsien; Sheu, Jiunn-Jye; Chua, Sarah; Chang, Chia-Lo; Cho, Chung-Lung; Leu, Steve; Yip, Hon-Kan

2013-05-31

This study tested the hypothesis that cyclosporine (CsA)-supported syngeneic adipose-derived mesenchymal stem cell (ADMSC) therapy offered superior attenuation of acute ischemia-reperfusion (IR) kidney injury to either therapy alone. Adult Sprague-Dawley rats (n = 40) were equally divided into group 1 (sham controls), group 2 (IR injury), group 3 (IR + CsA (20 mg/kg at 1 and 24 hours after procedure)), group 4 (syngeneic ADMSC (1.2×106) at 1, 6 and 24 hours after procedure), and group 5 (IR + CsA-ADMSC). By 72 hours after the IR procedure, the creatinine level and the ratio of urine protein to creatinine were highest in group 2 and lowest in group 1, and significantly higher in groups 3 and 4 than in group 5 (all P <0.05 for inter-group comparisons), but showed no differences between groups 3 and 4 (P >0.05). The inflammatory biomarkers at mRNA (matrix metalloproteinase-9, RANTES, TNF-α), protein (TNF-α, NF-κB, intercellular adhesion molecule-1, platelet-derived growth factor), and cellular (CD68+) levels of IR kidney showed a similar pattern compared with that of creatinine in all groups (all P <0.05 for inter-group comparisons). The protein expressions of oxidative stress (oxidized protein), reactive oxygen species (NADPH oxidases NOX-1, NOX-2), apoptosis (Bcl-2-associated X protein, caspase-3 and poly(ADP-ribose) polymerase) and DNA damage (phosphorylated H2A histone family member X-positive, proliferating cell nuclear antigen-positive cells) markers exhibited a pattern similar to that of inflammatory mediators amongst all groups (all P <0.05 for inter-group comparisons). Expressions of antioxidant biomarkers at cellular (glutathione peroxidase, glutathione reductase, heme oxygenase-1 (HO-1)) and protein (NADPH dehydrogenase (quinone)-1, HO-1, endothelial nitric oxide synthase) levels, and endothelial progenitor cell markers (C-X-C chemokine receptor type 4-positive, stromal cell-derived factor-1α-positive) were lowest in groups 1 and 2, higher in groups 3 and 4, and highest in group 5 (all P <0.05 for inter-group comparisons). Combination therapy using CsA plus ADMSCs offers improved protection against acute IR kidney injury.

Electromagnetic interference of cardiac rhythmic monitoring devices to radio frequency identification: analytical analysis and mitigation methodology.

PubMed

Ogirala, Ajay; Stachel, Joshua R; Mickle, Marlin H

2011-11-01

Increasing density of wireless communication and development of radio frequency identification (RFID) technology in particular have increased the susceptibility of patients equipped with cardiac rhythmic monitoring devices (CRMD) to environmental electro magnetic interference (EMI). Several organizations reported observing CRMD EMI from different sources. This paper focuses on mathematically analyzing the energy as perceived by the implanted device, i.e., voltage. Radio frequency (RF) energy transmitted by RFID interrogators is considered as an example. A simplified front-end equivalent circuit of a CRMD sensing circuitry is proposed for the analysis following extensive black-box testing of several commercial pacemakers and implantable defibrillators. After careful understanding of the mechanics of the CRMD signal processing in identifying the QRS complex of the heart-beat, a mitigation technique is proposed. The mitigation methodology introduced in this paper is logical in approach, simple to implement and is therefore applicable to all wireless communication protocols.

Robust Nucleus/Cell Detection and Segmentation in Digital Pathology and Microscopy Images: A Comprehensive Review

PubMed Central

Xing, Fuyong; Yang, Lin

2016-01-01

Digital pathology and microscopy image analysis is widely used for comprehensive studies of cell morphology or tissue structure. Manual assessment is labor intensive and prone to inter-observer variations. Computer-aided methods, which can significantly improve the objectivity and reproducibility, have attracted a great deal of interest in recent literatures. Among the pipeline of building a computer-aided diagnosis system, nucleus or cell detection and segmentation play a very important role to describe the molecular morphological information. In the past few decades, many efforts have been devoted to automated nucleus/cell detection and segmentation. In this review, we provide a comprehensive summary of the recent state-of-the-art nucleus/cell segmentation approaches on different types of microscopy images including bright-field, phase-contrast, differential interference contrast (DIC), fluorescence, and electron microscopies. In addition, we discuss the challenges for the current methods and the potential future work of nucleus/cell detection and segmentation. PMID:26742143

Theoretical Limits on Multiuser Molecular Communication in Internet of Nano-Bio Things.

PubMed

Dinc, Ergin; Akan, Ozgur B

2017-06-01

In nano-bio networks, multiple transmitter-receiver pairs will operate in the same medium. Both inter-symbol interference and multi-user interference can cause saturation at the receiver side, and this effect may cause an outage. Thus, we propose a tractable framework to calculate the theoretical operating points for fully absorbing receiver.

The Improvement of Bone-Tendon Fixation by Porous Titanium Interference Screw: A Rabbit Animal Model.

PubMed

Tsai, Pei-I; Chen, Chih-Yu; Huang, Shu-Wei; Yang, Kuo-Yi; Lin, Tzu-Hung; Chen, San-Yuan; Sun, Jui-Sheng

2018-05-04

The interference screw is a widely used fixation device in the anterior cruciate ligament (ACL) reconstruction surgeries. Despite the generally satisfactory results, problems of using interference screws were reported. By using additive manufacturing (AM) technology, we developed an innovative titanium alloy (Ti 6 Al 4 V) interference screw with rough surface and inter-connected porous structure designs to improve the bone-tendon fixation. An innovative Ti 6 Al 4 V interference screws were manufactured by AM technology. In vitro mechanical tests were performed to validate its mechanical properties. Twenty-seven New Zealand white rabbits were randomly divided into control and AM screw groups for biomechanical analyses and histological analysis at 4, 8 and 12 weeks postoperatively; while micro-CT analysis was performed at 12 weeks postoperatively. The biomechanical tests showed that the ultimate failure load in the AM interference screw group was significantly higher than that in the control group at all tested periods. These results were also compatible with the findings of micro-CT and histological analyses. In micro-CT analysis, the bone-screw gap was larger in the control group; while for the additive manufactured screw, the screw and bone growth was in close contact. In histological study, the bone-screw gaps were wider in the control group and were almost invisible in the AM screw group. The innovative AM interference screws with surface roughness and inter-connected porous architectures demonstrated better bone-tendon-implant integration, and resulted in stronger biomechanical characteristics when compared to traditional screws. These advantages can be transferred to future interference screw designs to improve their clinical performance. The AM interference screw could improve graft fixation and eventually result in better biomechanical performance of the bone-tendon-screw construct. The innovative AM interference screws can be transferred to future interference screw designs to improve the performance of implants. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Comparing Pain and Depressive Symptoms of Chronic Opioid Therapy Patients Receiving Dose Reduction and Risk Mitigation Initiatives With Usual Care.

PubMed

Thakral, Manu; Walker, Rod L; Saunders, Kathleen; Shortreed, Susan M; Parchman, Michael; Hansen, Ryan N; Ludman, Evette; Sherman, Karen J; Dublin, Sascha; Von Korff, Michael

2018-01-01

Dose reduction and risk mitigation initiatives have been recommended to reduce opioid-related risks among patients receiving chronic opioid therapy (COT), but questions remain over whether these initiatives worsen pain control and quality of life. In 2014 to 2015, we interviewed 1,588 adult COT patients within a health care system in Washington State and compared those who received dose reduction and risk mitigation initiatives in primary care clinics (intervention) with patients in comparable health care settings without initiatives (control). The primary outcomes were pain assessed using the pain, enjoyment, and general activity (PEG) scale, a 3-item scale to assess global pain intensity and interference, with secondary measures including depression (Patient Health Questionnaire-8 scale). Generalized estimating equations for linear regression models were used to estimate differences in mean scores between intervention and control sites. Estimated differences, adjusted for patient characteristics and weighted for nonresponse, between patients at intervention and control clinics were not clinically significant for the PEG (-.03, 95% confidence interval = -.25 to .19) or Patient Health Questionnaire-8 (-.64, 95% confidence interval = -1.19 to -.08). We found no evidence that COT patients in clinics with dose reduction and risk mitigation initiatives had clinically meaningful differences in pain intensity, interference with activities and enjoyment of life, or depressive symptoms compared with control health care settings. This article evaluates the effect of dose reduction and risk mitigation initiatives, such as those recently recommended by the Centers for Disease Control and Prevention, to reduce risks associated with COT on global pain and interference, depressive symptoms, and perceived pain relief and bothersomeness of side effects. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

GNSS Space-Time Interference Mitigation and Attitude Determination in the Presence of Interference Signals

PubMed Central

Daneshmand, Saeed; Jahromi, Ali Jafarnia; Broumandan, Ali; Lachapelle, Gérard

2015-01-01

The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios. PMID:26016909

GNSS space-time interference mitigation and attitude determination in the presence of interference signals.

PubMed

Daneshmand, Saeed; Jahromi, Ali Jafarnia; Broumandan, Ali; Lachapelle, Gérard

2015-05-26

The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios.

A New Hybrid Scheme for Preventing Channel Interference and Collision in Mobile Networks

NASA Astrophysics Data System (ADS)

Kim, Kyungjun; Han, Kijun

This paper proposes a new hybrid scheme based on a given set of channels for preventing channel interference and collision in mobile networks. The proposed scheme is designed for improving system performance, focusing on enhancement of performance related to path breakage and channel interference. The objective of this scheme is to improve the performance of inter-node communication. Simulation results from this paper show that the new hybrid scheme can reduce a more control message overhead than a conventional random scheme.

Assessment and mitigation of diagnostic-generated electromagnetic interference at the National Ignition Facilitya)

NASA Astrophysics Data System (ADS)

Brown, C. G.; Ayers, J.; Felker, B.; Ferguson, W.; Holder, J. P.; Nagel, S. R.; Piston, K. W.; Simanovskaia, N.; Throop, A. L.; Chung, M.; Hilsabeck, T.

2012-10-01

Electromagnetic interference (EMI) is an ever-present challenge at laser facilities such as the National Ignition Facility (NIF). The major source of EMI at such facilities is laser-target interaction that can generate intense electromagnetic fields within, and outside of, the laser target chamber. In addition, the diagnostics themselves can be a source of EMI, even interfering with themselves. In this paper we describe EMI generated by ARIANE and DIXI, present measurements, and discuss effects of the diagnostic-generated EMI on ARIANE's CCD and on a PMT nearby DIXI. Finally we present some of the efforts we have made to mitigate the effects of diagnostic-generated EMI on NIF diagnostics.

The Mitigation of Radio Noise and Interference from On-Site Sources at Radio Receiving Sites

DTIC Science & Technology

2009-11-01

are rated to handle the maximum signal, noise, and interference power applied to them. All signal splitters and other components that contain ferrite ...other sources on the campus. 83 A.1.5 Data Recording Until a few years ago, data was recorded by freezing the operation of the 7200B display

Extending the time interval for applying herbicide in cut-stump treatments on American beech

Treesearch

Jeffrey D. Kochenderfer; James N. Kochenderfer; Gary W. Miller

2013-01-01

American Beech (Fagus grandifolia Ehrh.) root sprouts often form dense understories that interfere with tree reproduction throughout much of the eastern hardwood region. The cut-stump treatment, whereby herbicide is applied to the stump within a few hours after a larger beech is felled, has been shown to mitigate the interference problem by...

An update on mobile phones interference with medical devices.

PubMed

Mahmoud Pashazadeh, Ali; Aghajani, Mahdi; Nabipour, Iraj; Assadi, Majid

2013-10-01

Mobile phones' electromagnetic interference with medical devices is an important issue for the medical safety of patients who are using life-supporting medical devices. This review mainly focuses on mobile phones' interference with implanted medical devices and with medical equipment located in critical areas of hospitals. A close look at the findings reveals that mobile phones may adversely affect the functioning of medical devices, and the specific effect and the degree of interference depend on the applied technology and the separation distance. According to the studies' findings and the authors' recommendations, besides mitigating interference, using mobile phones at a reasonable distance from medical devices and developing technology standards can lead to their effective use in hospital communication systems.

Radio-Frequency Interference (RFI) Mitigation for the Soil, Moisture Active/Passive (SMAP) Radiometer

NASA Technical Reports Server (NTRS)

Bradley, Damon; Brambora, Cliff; Wong, Mark Englin; Miles, Lynn; Durachka, David; Farmer, Brian; Mohammed, Priscilla; Piepmier, Jeff; Medeiros, Jim; Martin Neil;

Proposal of DCS-OFDM-PON upstream transmission with intensity modulator and collective self-coherent detection

NASA Astrophysics Data System (ADS)

Zhang, Jing; Yang, Heming; Zhao, Difu; Qiu, Kun

2016-07-01

We introduce digital coherent superposition (DCS) into optical access network and propose a DCS-OFDM-PON upstream transmission scheme using intensity modulator and collective self-coherent detection. The generated OFDM signal is real based on Hermitian symmetry, which can be used to estimate the common phase error (CPE) by complex conjugate subcarrier pairs without any pilots. In simulation, we transmit an aggregated 40 Gb/s optical OFDM signal from two ONUs. The transmission performance with DCS is slightly better after 25 km transmission without relative transmission time delay. The fiber distance for different ONUs to RN are not same in general and there is relative transmission time delay between ONUs, which causes inter-carrier-interference (ICI) power increasing and degrades the transmission performance. The DCS can mitigate the ICI power and the DCS-OFDM-PON upstream transmission outperforms the conventional OFDM-PON. The CPE estimation is by using two pairs of complex conjugate subcarriers without redundancy. The power variation can be 9 dB in DCS-OFDM-PON, which is enough to tolerate several kilometers fiber length difference between the ONUs.

Experimental Demonstration of Long-Range Underwater Acoustic Communication Using a Vertical Sensor Array

PubMed Central

Zhao, Anbang; Zeng, Caigao; Hui, Juan; Ma, Lin; Bi, Xuejie

2017-01-01

This paper proposes a composite channel virtual time reversal mirror (CCVTRM) for vertical sensor array (VSA) processing and applies it to long-range underwater acoustic (UWA) communication in shallow water. Because of weak signal-to-noise ratio (SNR), it is unable to accurately estimate the channel impulse response of each sensor of the VSA, thus the traditional passive time reversal mirror (PTRM) cannot perform well in long-range UWA communication in shallow water. However, CCVTRM only needs to estimate the composite channel of the VSA to accomplish time reversal mirror (TRM), which can effectively mitigate the inter-symbol interference (ISI) and reduce the bit error rate (BER). In addition, the calculation of CCVTRM is simpler than traditional PTRM. An UWA communication experiment using a VSA of 12 sensors was conducted in the South China Sea. The experiment achieves a very low BER communication at communication rate of 66.7 bit/s over an 80 km range. The results of the sea trial demonstrate that CCVTRM is feasible and can be applied to long-range UWA communication in shallow water. PMID:28653976

Efficient Graph-Based Resource Allocation Scheme Using Maximal Independent Set for Randomly- Deployed Small Star Networks

PubMed Central

Zhou, Jian; Wang, Lusheng; Wang, Weidong; Zhou, Qingfeng

2017-01-01

In future scenarios of heterogeneous and dense networks, randomly-deployed small star networks (SSNs) become a key paradigm, whose system performance is restricted to inter-SSN interference and requires an efficient resource allocation scheme for interference coordination. Traditional resource allocation schemes do not specifically focus on this paradigm and are usually too time consuming in dense networks. In this article, a very efficient graph-based scheme is proposed, which applies the maximal independent set (MIS) concept in graph theory to help divide SSNs into almost interference-free groups. We first construct an interference graph for the system based on a derived distance threshold indicating for any pair of SSNs whether there is intolerable inter-SSN interference or not. Then, SSNs are divided into MISs, and the same resource can be repetitively used by all the SSNs in each MIS. Empirical parameters and equations are set in the scheme to guarantee high performance. Finally, extensive scenarios both dense and nondense are randomly generated and simulated to demonstrate the performance of our scheme, indicating that it outperforms the classical max K-cut-based scheme in terms of system capacity, utility and especially time cost. Its achieved system capacity, utility and fairness can be close to the near-optimal strategy obtained by a time-consuming simulated annealing search. PMID:29113109

Alternatives to in vivo tests to detect endocrine disrupting chemicals (EDCs) in fish and amphibians--screening for estrogen, androgen and thyroid hormone disruption.

PubMed

Scholz, S; Renner, P; Belanger, S E; Busquet, F; Davi, R; Demeneix, B A; Denny, J S; Léonard, M; McMaster, M E; Villeneuve, D L; Embry, M R

2013-01-01

Endocrine disruption is considered a highly relevant hazard for environmental risk assessment of chemicals, plant protection products, biocides and pharmaceuticals. Therefore, screening tests with a focus on interference with estrogen, androgen, and thyroid hormone pathways in fish and amphibians have been developed. However, they use a large number of animals and short-term alternatives to animal tests would be advantageous. Therefore, the status of alternative assays for endocrine disruption in fish and frogs was assessed by a detailed literature analysis. The aim was to (i) determine the strengths and limitations of alternative assays and (ii) present conclusions regarding chemical specificity, sensitivity, and correlation with in vivo data. Data from 1995 to present were collected related to the detection/testing of estrogen-, androgen-, and thyroid-active chemicals in the following test systems: cell lines, primary cells, fish/frog embryos, yeast and cell-free systems. The review shows that the majority of alternative assays measure effects directly mediated by receptor binding or resulting from interference with hormone synthesis. Other mechanisms were rarely analysed. A database was established and used for a quantitative and comparative analysis. For example, a high correlation was observed between cell-free ligand binding and cell-based reporter cell assays, between fish and frog estrogenic data and between fish embryo tests and in vivo reproductive effects. It was concluded that there is a need for a more systematic study of the predictive capacity of alternative tests and ways to reduce inter- and intra-assay variability.

Characterization and Mitigation of Radio Frequency Interference in PolSAR Data

NASA Astrophysics Data System (ADS)

Tao, Mingliang; Zhou, Feng; Zhang, Zijing

2017-11-01

Polarimetric synthetic aperture radar (PolSAR) is a very important instrument for active remote sensing. However, it is common to find that PolSAR echoes are often contaminated by incoherent electromagnetic interference, which is referred to as radio frequency interference (RFI). The analysis of RFI signatures and its influence on PolSAR data seems to be lacking in existing literatures, especially for PolSAR post products, such as the polarimetric decomposition parameters and clustering result. The goal of this paper is to reveal the link between RFI and polarization, as well as to analyze the impact of interference on PolSAR image and its post products. Qualitative and quantitative analyses of the adverse impact of RFI on the real measured NASA/Jet Propulsion Laboratory (JPL) Uninhabited Aerial Vehicle Synthetic Aperture Radar data set are illustrated from two perspectives, that is, evaluation of imaging quality and interpretation of scattering mechanisms. The point target response and effective number of looks are evaluated for assessing the distortion to focusing quality. Further, we discussed the characteristics of ultra wideband RFI and proposed a mitigation method using nonnegative matrix factorization along azimuth direction. The experimental results indicate the effectiveness of the proposed method.

Minimizing End-to-End Interference in I/O Stacks Spanning Shared Multi-Level Buffer Caches

ERIC Educational Resources Information Center

Patrick, Christina M.

2011-01-01

This thesis presents an end-to-end interference minimizing uniquely designed high performance I/O stack that spans multi-level shared buffer cache hierarchies accessing shared I/O servers to deliver a seamless high performance I/O stack. In this thesis, I show that I can build a superior I/O stack which minimizes the inter-application interference…

Assessment and Mitigation of Diagnostic-Generated Electromagnetic Interference at the National Ignition Facility

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

Brown, C G; Ayers, M J; Felker, B

2012-04-20

Electromagnetic interference (EMI) is an ever-present challenge at laser facilities such as the National Ignition Facility (NIF). The major source of EMI at such facilities is laser-target interaction that can generate intense electromagnetic fields within, and outside of, the laser target chamber. In addition, the diagnostics themselves can be a source of EMI, even interfering with themselves. In this paper we describe EMI generated by ARIANE and DIXI, present measurements, and discuss effects of the diagnostic-generated EMI on ARIANE's CCD and on a PMT nearby DIXI. Finally we present some of the efforts we have made to mitigate the effectsmore » of diagnostic-generated EMI on NIF diagnostics.« less

SU-D-207A-07: The Effects of Inter-Cycle Respiratory Motion Variation On Dose Accumulation in Single Fraction MR-Guided SBRT Treatment of Renal Cell Carcinoma

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

Stemkens, B; Glitzner, M; Kontaxis, C

Purpose: To assess the dose deposition in simulated single-fraction MR-Linac treatments of renal cell carcinoma, when inter-cycle respiratory motion variation is taken into account using online MRI. Methods: Three motion characterization methods, with increasing complexity, were compared to evaluate the effect of inter-cycle motion variation and drifts on the accumulated dose for an SBRT kidney MR-Linac treatment: 1) STATIC, in which static anatomy was assumed, 2) AVG-RESP, in which 4D-MRI phase-volumes were time-weighted, based on the respiratory phase and 3) PCA, in which 3D volumes were generated using a PCA-model, enabling the detection of inter-cycle variations and drifts. An experimentalmore » ITV-based kidney treatment was simulated in a 1.5T magnetic field on three volunteer datasets. For each volunteer a retrospectively sorted 4D-MRI (ten respiratory phases) and fast 2D cine-MR images (temporal resolution = 476ms) were acquired to simulate MR-imaging during radiation. For each method, the high spatio-temporal resolution 3D volumes were non-rigidly registered to obtain deformation vector fields (DVFs). Using the DVFs, pseudo-CTs (generated from the 4D-MRI) were deformed and the dose was accumulated for the entire treatment. The accuracies of all methods were independently determined using an additional, orthogonal 2D-MRI slice. Results: Motion was most accurately estimated using the PCA method, which correctly estimated drifts and inter-cycle variations (RMSE=3.2, 2.2, 1.1mm on average for STATIC, AVG-RESP and PCA, compared to the 2DMRI slice). Dose-volume parameters on the ITV showed moderate changes (D99=35.2, 32.5, 33.8Gy for STATIC, AVG-RESP and PCA). AVG-RESP showed distinct hot/cold spots outside the ITV margin, which were more distributed for the PCA scenario, since inter-cycle variations were not modeled by the AVG-RESP method. Conclusion: Dose differences were observed when inter-cycle variations were taken into account. The increased inter-cycle randomness in motion as captured by the PCA model mitigates the local (erroneous) hotspots estimated by the AVG-RESP method.« less

Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization

NASA Astrophysics Data System (ADS)

Gramajo, A. A.; Della Picca, R.; Arbó, D. G.

2017-08-01

We present a theoretical study of ionization of the hydrogen atom due to an XUV pulse in the presence of an infrared (IR) laser with both fields linearly polarized in the same direction. In particular, we study the energy distribution of photoelectrons emitted perpendicularly to the polarization direction. As we previously showed in Gramajo et al. [Phys. Rev. A 94, 053404 (2016), 10.1103/PhysRevA.94.053404] for parallel emission, by means of a very simple semiclassical model which considers electron trajectories born at different ionization times, the electron energy spectrum can be interpreted as the interplay of intra- and intercycle interferences. However, contrary to the case of parallel emission the intracycle interference pattern stems from the coherent superposition of four electron trajectories giving rise to (i) interference of electron trajectories born during the same half cycle (intra-half-cycle interference) and (ii) interference between electron trajectories born during the first half cycle with those born during the second half cycle (inter-half-cycle interference). The intercycle interference is responsible for the formation of the sidebands. We also show that the destructive inter-half-cycle interference for the absorption and emission of an even number of IR laser photons is responsible for the characteristic sidebands in the perpendicular direction separated by twice the IR photon energy. This contrasts with the emission along the polarization axis (all sideband orders are present) since intra-half-cycle interferences do not exist in that case. The intracycle interference pattern works as a modulation of the sidebands and, in the same way, it is modulated by the intra-half-cycle interference pattern. We analyze the dependence of the energy spectrum on the laser intensity and the time delay between the XUV pulse and the IR laser. Finally, we show that our semiclassical simulations are in very good agreement with quantum calculations within the strong-field approximation and the numerical solution of the time-dependent Schrödinger equation, giving rise to nonzero emission, in contraposition to other theories.

Cyclosporine-assisted adipose-derived mesenchymal stem cell therapy to mitigate acute kidney ischemia–reperfusion injury

PubMed Central

2013-01-01

Introduction This study tested the hypothesis that cyclosporine (CsA)-supported syngeneic adipose-derived mesenchymal stem cell (ADMSC) therapy offered superior attenuation of acute ischemia–reperfusion (IR) kidney injury to either therapy alone. Methods Adult Sprague–Dawley rats (n = 40) were equally divided into group 1 (sham controls), group 2 (IR injury), group 3 (IR + CsA (20 mg/kg at 1 and 24 hours after procedure)), group 4 (syngeneic ADMSC (1.2×106) at 1, 6 and 24 hours after procedure), and group 5 (IR + CsA-ADMSC). Results By 72 hours after the IR procedure, the creatinine level and the ratio of urine protein to creatinine were highest in group 2 and lowest in group 1, and significantly higher in groups 3 and 4 than in group 5 (all P <0.05 for inter-group comparisons), but showed no differences between groups 3 and 4 (P >0.05). The inflammatory biomarkers at mRNA (matrix metalloproteinase-9, RANTES, TNF-α), protein (TNF-α, NF-κB, intercellular adhesion molecule-1, platelet-derived growth factor), and cellular (CD68+) levels of IR kidney showed a similar pattern compared with that of creatinine in all groups (all P <0.05 for inter-group comparisons). The protein expressions of oxidative stress (oxidized protein), reactive oxygen species (NADPH oxidases NOX-1, NOX-2), apoptosis (Bcl-2–associated X protein, caspase-3 and poly(ADP-ribose) polymerase) and DNA damage (phosphorylated H2A histone family member X-positive, proliferating cell nuclear antigen-positive cells) markers exhibited a pattern similar to that of inflammatory mediators amongst all groups (all P <0.05 for inter-group comparisons). Expressions of antioxidant biomarkers at cellular (glutathione peroxidase, glutathione reductase, heme oxygenase-1 (HO-1)) and protein (NADPH dehydrogenase (quinone)-1, HO-1, endothelial nitric oxide synthase) levels, and endothelial progenitor cell markers (C-X-C chemokine receptor type 4-positive, stromal cell-derived factor-1α-positive) were lowest in groups 1 and 2, higher in groups 3 and 4, and highest in group 5 (all P <0.05 for inter-group comparisons). Conclusion Combination therapy using CsA plus ADMSCs offers improved protection against acute IR kidney injury. PMID:23726287

Note: Experimental observation of nano-channel pattern in light sheet laser interference nanolithography system

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

Mohan, Kavya; Mondal, Partha Pratim, E-mail: partha@iap.iisc.ernet.in

We experimentally observed nano-channel-like pattern in a light-sheet based interference nanolithography system. The optical system created nano-channel-like patterned illumination. Coherent counter-propagating light sheets are made to interfere at and near geometrical focus along the propagation z-axis. This results in the formation of nano-channel-like pattern (of size ≈ 300 nm and inter-channel periodicity of ≈337.5 nm) inside the sample due to constructive and destructive interference. In addition, the technique has the ability to generate large area patterning using larger light-sheets. Exciting applications are in the broad field of nanotechnology (nano-electronics and nano-fluidics).

Defense Science Board Task Force on The Future of the Global Positioning System

DTIC Science & Technology

2005-10-01

interference. Incorporate a fully reprogrammable Navigation Payload aboard GPS satellites as soon as practicable to enable future flexibility in signal...its use increases in automobiles , it is becoming a significant factor in E-911-type situations, where emergency vehicles are dispatched to accident...mitigation for GPS against both intentional and unintentional interference. Incorporate a fully reprogrammable Navigation Payload aboard GPS

Family Interference with Work and Workplace Cognitive Failure: The Mitigating Role of Recovery Experiences

ERIC Educational Resources Information Center

Lapierre, Laurent M.; Hammer, Leslie B.; Truxillo, Donald M.; Murphy, Lauren A.

2012-01-01

The first goal of this study was to test whether family interference with work (FIW) is positively related to increased workplace cognitive failure (WCF), which is defined as errors made at work that indicate lapses in memory (e.g., failing to recall work procedures), attention (e.g., not fully listening to instruction), and motor function (e.g.,…

Calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry assays and its application in supporting microdose absolute bioavailability studies.

PubMed

Gu, Huidong; Wang, Jian; Aubry, Anne-Françoise; Jiang, Hao; Zeng, Jianing; Easter, John; Wang, Jun-sheng; Dockens, Randy; Bifano, Marc; Burrell, Richard; Arnold, Mark E

2012-06-05

A methodology for the accurate calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) assays and its application in supporting microdose absolute bioavailability studies are reported for the first time. For simplicity, this calculation methodology and the strategy to minimize the isotopic interference are demonstrated using a simple molecule entity, then applied to actual development drugs. The exact isotopic interferences calculated with this methodology were often much less than the traditionally used, overestimated isotopic interferences simply based on the molecular isotope abundance. One application of the methodology is the selection of a stable isotopically labeled internal standard (SIL-IS) for an LC-MS/MS bioanalytical assay. The second application is the selection of an SIL analogue for use in intravenous (i.v.) microdosing for the determination of absolute bioavailability. In the case of microdosing, the traditional approach of calculating isotopic interferences can result in selecting a labeling scheme that overlabels the i.v.-dosed drug or leads to incorrect conclusions on the feasibility of using an SIL drug and analysis by LC-MS/MS. The methodology presented here can guide the synthesis by accurately calculating the isotopic interferences when labeling at different positions, using different selective reaction monitoring (SRM) transitions or adding more labeling positions. This methodology has been successfully applied to the selection of the labeled i.v.-dosed drugs for use in two microdose absolute bioavailability studies, before initiating the chemical synthesis. With this methodology, significant time and cost saving can be achieved in supporting microdose absolute bioavailability studies with stable labeled drugs.

Director, Operational Test and Evaluation FY 2014 Annual Report

DTIC Science & Technology

2015-01-01

Federal Departments and Agencies. Mitigation measures such as curtailment of wind turbine operations during test periods, identification of alternative...impact of wind turbines on ground-based and airborne radars, and this investment may help mitigate interference of wind turbines with test range...Frequency Active (SURTASS CLFA) Test Plan Tactical Unmanned Aircraft System Tactical Common Data Link (Shadow) FOT&E OTA Test Plan Tempest Wind 2014

Large inter-individual and intra-individual variability in the effect of perceptual load

PubMed Central

Yeshurun, Yaffa

2017-01-01

This study examined whether the recurrent difficulty to replicate results obtained with paradigms measuring distractor processing as a function of perceptual load is due to individual differences. We first reanalyzed, at the individual level, the data of eight previously reported experiments. These reanalyses revealed substantial inter-individual differences, with particularly low percentage of participants whose performance matched the load theory’s predictions (i.e., larger distractor interference with low than high levels of load). Moreover, frequently the results were opposite to the theory's predictions–larger interference in the high than low load condition; and often a reversed compatibility effect emerged–better performance in the incompatible than neutral condition. Subsequently, seven observers participated in five identical experimental sessions. If the observed inter-individual differences are due to some stable trait or perceptual capacity, similar results should have emerged in all sessions of a given participant. However, all seven participants showed large between-sessions variations with similar patterns to those found between participants. These findings question the theoretical foundation implemented with these paradigms, as none of the theories suggested thus far can account for such inter- and intra-individual differences. Thus, these paradigms should be used with caution until further research will provide better understanding of what they actually measure. PMID:28406997

Time manages interference in visual short-term memory.

PubMed

Smith, Amy V; McKeown, Denis; Bunce, David

2017-09-01

Emerging evidence suggests that age-related declines in memory may reflect a failure in pattern separation, a process that is believed to reduce the encoding overlap between similar stimulus representations during memory encoding. Indeed, behavioural pattern separation may be indexed by a visual continuous recognition task in which items are presented in sequence and observers report for each whether it is novel, previously viewed (old), or whether it shares features with a previously viewed item (similar). In comparison to young adults, older adults show a decreased pattern separation when the number of items between "old" and "similar" items is increased. Yet the mechanisms of forgetting underpinning this type of recognition task are yet to be explored in a cognitively homogenous group, with careful control over the parameters of the task, including elapsing time (a critical variable in models of forgetting). By extending the inter-item intervals, number of intervening items and overall decay interval, we observed in a young adult sample (N = 35, M age  = 19.56 years) that the critical factor governing performance was inter-item interval. We argue that tasks using behavioural continuous recognition to index pattern separation in immediate memory will benefit from generous inter-item spacing, offering protection from inter-item interference.

A Novel Capacity Analysis for Wireless Backhaul Mesh Networks

NASA Astrophysics Data System (ADS)

Chung, Tein-Yaw; Lee, Kuan-Chun; Lee, Hsiao-Chih

This paper derived a closed-form expression for inter-flow capacity of a backhaul wireless mesh network (WMN) with centralized scheduling by employing a ring-based approach. Through the definition of an interference area, we are able to accurately describe a bottleneck collision area for a WMN and calculate the upper bound of inter-flow capacity. The closed-form expression shows that the upper bound is a function of the ratio between transmission range and network radius. Simulations and numerical analysis show that our analytic solution can better estimate the inter-flow capacity of WMNs than that of previous approach.

Regulatory T cells and the immune pathogenesis of prenatal infection

PubMed Central

Rowe, Jared H.; Ertelt, James M.; Xin, Lijun; Way, Sing Sing

2013-01-01

Pregnancy in placental mammals offers exceptional comprehensive benefits of in utero protection, nutrition, and elimination of metabolic waste for the developing fetus. However, these advantages also require durable strategies to mitigate maternal rejection of fetal tissue expressing foreign paternal antigens. Since the initial postulate of expanded maternal immune tolerance by Sir Peter Medawar 60 years ago, an amazingly elaborate assortment of molecular and cellular modifications acting both locally at the maternal placental interface and systemically have been shown to silence potentially detrimental maternal immune responses. In turn, simultaneously maintaining host defense against the infinite array of potential pathogens during pregnancy is equally important. Fortunately, resistance against most infections is preserved seamlessly throughout gestation. On the other hand, recent studies on pathogens with unique predisposition for prenatal infection have uncovered distinctive holes in host defense associated with the reproductive process. Using these infections to probe the response during pregnancy, the immune suppressive regulatory subset of maternal CD4 T cells has been increasingly shown to dictate the inter-workings between prenatal infection susceptibility and pathogenesis of ensuing pregnancy complications. Herein, the recent literature suggesting a necessity for maternal regulatory T cells in pregnancy induced immunological shifts that sustain fetal tolerance is reviewed. Additional discussion is focused on how expansion of maternal regulatory T cell suppression may become exploited by pathogens that cause prenatal infection, and the perilous potential of infection induced immune activation that may mitigate fetal tolerance and inadvertently inject hostility into the protective in utero environment. PMID:23929902

Efficient place and route enablement of 5-tracks standard-cells through EUV compatible N5 ruleset

NASA Astrophysics Data System (ADS)

Matti, L.; Gerousis, V.; Berekovic, M.; Debacker, P.; Sherazi, S. M. Y.; Milojevic, D.; Baert, R.; Ryckaert, J.; Kim, Ryoung-han; Verkest, Diederik; Raghavan, P.

2018-03-01

In imec predictive N5 technology platform (poly pitch 42nm, metal pitch 32nm), enabling cell height reduction from 6 to 5 tracks constitutes an interesting opportunity to reduce area of digital IP-blocks without increasing wafer cost. From a physical point of view, the two main challenges of reducing the number of tracks are posed by the increased difficulty of completing inter-cell connections in standard cell design, and by increased pin density that makes more challenging for the router to maintain high placement densities. Both these issues can potentially result into cell and chip area enlargement, thus mitigating or canceling the benefits of moving to 5-Tracks. In this study this side effect was avoided through a careful Design-Technology Co-Optimization approach (DTCO) [1], where a set of design arcs was used in conjunction with an EUV compatible ruleset that allowed efficient 5-Tracks standard cell design, resulting in final area gains up to 17% that were validated through a commercial state-of-the-art Place and Route (P&R) flow.

Systematic impact assessment on inter-basin water transfer projects of the Hanjiang River Basin in China

NASA Astrophysics Data System (ADS)

Zhou, Yanlai; Guo, Shenglian; Hong, Xingjun; Chang, Fi-John

2017-10-01

China's inter-basin water transfer projects have gained increasing attention in recent years. This study proposes an intelligent water allocation methodology for establishing optimal inter-basin water allocation schemes and assessing the impacts of water transfer projects on water-demanding sectors in the Hanjiang River Basin of China. We first analyze water demands for water allocation purpose, and then search optimal water allocation strategies for maximizing the water supply to water-demanding sectors and mitigating the negative impacts by using the Standard Genetic Algorithm (SGA) and Adaptive Genetic Algorithm (AGA), respectively. Lastly, the performance indexes of the water supply system are evaluated under different scenarios of inter-basin water transfer projects. The results indicate that: the AGA with adaptive crossover and mutation operators could increase the average annual water transfer from the Hanjiang River by 0.79 billion m3 (8.8%), the average annual water transfer from the Changjiang River by 0.18 billion m3 (6.5%), and the average annual hydropower generation by 0.49 billion kW h (5.4%) as well as reduce the average annual unmet water demand by 0.40 billion m3 (9.7%), as compared with the those of the SGA. We demonstrate that the proposed intelligent water allocation schemes can significantly mitigate the negative impacts of inter-basin water transfer projects on the reliability, vulnerability and resilience of water supply to the demanding sectors in water-supplying basins. This study has a direct bearing on more intelligent and effectual water allocation management under various scenarios of inter-basin water transfer projects.

Radio Frequency Interference Mitigation

NASA Astrophysics Data System (ADS)

An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

2017-09-01

The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

DTIC Science & Technology

2011-09-30

channel interference mitigation for underwater acoustic MIMO - OFDM . 3) Turbo equalization for OFDM modulated physical layer network coding. 4) Blind CFO...Underwater Acoustic MIMO - OFDM . MIMO - OFDM has been actively studied for high data rate communications over the bandwidthlimited underwater acoustic...with the cochannel interference (CCI) due to parallel transmissions in MIMO - OFDM . Our proposed receiver has the following components: 1

Measurement of the accumulation of water ice on optical components in cryogenic vacuum environments

NASA Astrophysics Data System (ADS)

Moeller, Trevor M.; Montgomery Smith, L.; Collins, Frank G.; Labello, Jesse M.; Rogers, James P.; Lowry, Heard S.; Crider, Dustin H.

2012-11-01

Standard vacuum practices mitigate the presence of water vapor and contamination inside cryogenic vacuum chambers. However, anomalies can occur in the facility that can cause the accumulation of amorphous water ice on optics and test articles. Under certain conditions, the amorphous ice on optical components shatters, which leads to a reduction in signal or failure of the component. An experiment was performed to study and measure the deposition of water (H2O) ice on optical surfaces under high-vacuum cryogenic conditions. Water was introduced into a cryogenic vacuum chamber, via a hydrated molecular sieve zeolite, through an effusion cell and impinged upon a quartz-crystal microbalance (QCM) and first-surface gold-plated mirror. A laser and photodiode setup, external to the vacuum chamber, monitored the multiple-beam interference reflectance of the ice-mirror configuration while the QCM measured the mass deposition. Data indicates that water ice, under these conditions, accumulates as a thin film on optical surfaces to thicknesses over 45 microns and can be detected and measured by nonintrusive optical methods which are based upon multiple-beam interference phenomena. The QCM validated the interference measurements. This experiment established proof-of-concept for a miniature system for monitoring ice accumulation within the chamber.

Radon Mitigation Approach in a Laboratory Measurement Room

PubMed Central

Blanco-Rodríguez, Patricia; Fernández-Serantes, Luis Alfonso; Otero-Pazos, Alberto; Calvo-Rolle, José Luis; de Cos Juez, Francisco Javier

2017-01-01

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to prevent radon from interfering in radioactive measurements. This study describes the implementation of radon mitigation systems at a radioactivity laboratory in order to reduce interferences in the different works carried out. A large set of radon concentration samples is obtained from measurements at the laboratory. While several mitigation methods were taken into account, the final applied solution is explained in detail, obtaining thus very good results by reducing the radon concentration by 76%. PMID:28492468

Radon Mitigation Approach in a Laboratory Measurement Room.

PubMed

Blanco-Rodríguez, Patricia; Fernández-Serantes, Luis Alfonso; Otero-Pazos, Alberto; Calvo-Rolle, José Luis; de Cos Juez, Francisco Javier

2017-05-11

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to prevent radon from interfering in radioactive measurements. This study describes the implementation of radon mitigation systems at a radioactivity laboratory in order to reduce interferences in the different works carried out. A large set of radon concentration samples is obtained from measurements at the laboratory. While several mitigation methods were taken into account, the final applied solution is explained in detail, obtaining thus very good results by reducing the radon concentration by 76%.

Tunable, high-sensitive measurement of inter-dot transition via tunneling induced absorption

NASA Astrophysics Data System (ADS)

Peng, Yandong; Yang, Aihong; Chen, Bing; Li, Lei; Liu, Shande; Guo, Hongju

2016-10-01

A tunable, narrow absorption spectrum induced by resonant tunneling is demonstrated and proposed for measuring interdot tunneling. Tunneling-induced absorption (TIA) arises from constructive interference between different transition paths, and the large nonlinear TIA significantly enhances the total absorption. The narrow nonlinear TIA spectrum is sensitive to inter-dot tunneling, and its sensor characteristics, including sensitivity and bandwidth, are investigated in weak-coupling and strong-coupling regimes, respectively.

Beam Design and User Scheduling for Nonorthogonal Multiple Access With Multiple Antennas Based on Pareto Optimality

NASA Astrophysics Data System (ADS)

Seo, Junyeong; Sung, Youngchul

2018-06-01

In this paper, an efficient transmit beam design and user scheduling method is proposed for multi-user (MU) multiple-input single-output (MISO) non-orthogonal multiple access (NOMA) downlink, based on Pareto-optimality. The proposed beam design and user scheduling method groups simultaneously-served users into multiple clusters with practical two users in each cluster, and then applies spatical zeroforcing (ZF) across clusters to control inter-cluster interference (ICI) and Pareto-optimal beam design with successive interference cancellation (SIC) to two users in each cluster to remove interference to strong users and leverage signal-to-interference-plus-noise ratios (SINRs) of interference-experiencing weak users. The proposed method has flexibility to control the rates of strong and weak users and numerical results show that the proposed method yields good performance.

Light Vector Meson Photoproduction off of 1H at Jefferson Lab and p-w Interference in the Leptonic Decay Channel

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

Djalali, Chaden; Paolone, Michael; Weygand, Dennis

2014-09-01

Although the phenomena of r – w interference has been studied at great length in pionic decay channel over the past 50 years, a study of the interference in a purely electromagnetic production and decay channel has never been performed on an elementary proton target until now. The only published photo-production data of the r - w leptonic decay channel was obtained in the early seventies on C and Be. An investigation of the r - w interference on a Hydrogen was recently completed at Jefferson Lab with the CLAS detector. The di-lepton spectra was fit with two inter- feringmore » relativistic Breit-Wigner functions, and the interference phase was extracted. Preliminary results will be compared to the previous experimental studies in nuclei.« less

Performance Evaluation of Cognitive Interference Channels Using a Spectrum Overlay Strategy

NASA Technical Reports Server (NTRS)

Knoblock, Eric J.

2018-01-01

The use of cognitive radios (CR) and cooperative communications techniques may assist in interference mitigation via sensing of the environment and dynamically altering communications parameters through the use of various mechanisms - one of which is the overlay technique. This report provides a performance analysis of an interference channel with a cognitive transceiver operating in an overlay configuration to evaluate the gains from using cognition. As shown in this report, a cognitive transceiver can simultaneously share spectrum while enhancing performance of non-cognitive nodes via knowledge of the communications channel as well as knowledge of neighboring users' modulation and coding schemes.

Polyatomic interferences on high precision uranium isotope ratio measurements by MC-ICP-MS: Applications to environmental sampling for nuclear safeguards

DOE PAGES

Pollington, Anthony D.; Kinman, William S.; Hanson, Susan K.; ...

2015-09-04

Modern mass spectrometry and separation techniques have made measurement of major uranium isotope ratios a routine task; however accurate and precise measurement of the minor uranium isotopes remains a challenge as sample size decreases. One particular challenge is the presence of isobaric interferences and their impact on the accuracy of minor isotope 234U and 236U measurements. Furthermore, we present techniques used for routine U isotopic analysis of environmental nuclear safeguards samples and evaluate polyatomic interferences that negatively impact accuracy as well as methods to mitigate their impacts.

Soil Moisture Active Passive (SMAP) Microwave Radiometer Radio-Frequency Interference (RFI) Mitigation: Initial On-Orbit Results

NASA Technical Reports Server (NTRS)

Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Johnson, Joel T.; Aksoy, Mustafa; Bringer, Alexandra

2015-01-01

The Soil Moisture Active Passive (SMAP) mission, launched in January 2015, provides global measurements of soil moisture using a microwave radiometer. SMAPs radiometer passband lies within the passive frequency allocation. However, both unauthorized in-band transmitters as well as out-of-band emissions from transmitters operating at frequencies adjacent to this allocated spectrum have been documented as sources of radio frequency interference (RFI) to the L-band radiometers on SMOS and Aquarius. The spectral environment consists of high RFI levels as well as significant occurrences of low level RFI equivalent to 0.1 to 10 K. The SMAP ground processor reports the antenna temperature both before and after RFI mitigation is applied. The difference between these quantities represents the detected RFI level. The presentation will review the SMAP RFI detection and mitigation procedure and discuss early on-orbit RFI measurements from the SMAP radiometer. Assessments of global RFI properties and source types will be provided, as well as the implications of these results for SMAP soil moisture measurements.

Programmed activation of cancer cell apoptosis: A tumor-targeted phototherapeutic topoisomerase I inhibitor

NASA Astrophysics Data System (ADS)

Shin, Weon Sup; Han, Jiyou; Kumar, Rajesh; Lee, Gyung Gyu; Sessler, Jonathan L.; Kim, Jong-Hoon; Kim, Jong Seung

2016-07-01

We report here a tumor-targeting masked phototherapeutic agent 1 (PT-1). This system contains SN-38—a prodrug of the topoisomerase I inhibitor irinotecan. Topoisomerase I is a vital enzyme that controls DNA topology during replication, transcription, and recombination. An elevated level of topoisomerase I is found in many carcinomas, making it an attractive target for the development of effective anticancer drugs. In addition, PT-1 contains both a photo-triggered moiety (nitrovanillin) and a cancer targeting unit (biotin). Upon light activation in cancer cells, PT-1 interferes with DNA re-ligation, diminishes the expression of topoisomerase I, and enhances the expression of inter alia mitochondrial apoptotic genes, death receptors, and caspase enzymes, inducing DNA damage and eventually leading to apoptosis. In vitro and in vivo studies showed significant inhibition of cancer growth and the hybrid system PT-1 thus shows promise as a programmed photo-therapeutic (“phototheranostic”).

Optical Layout Analysis of Polarization Interference Imaging Spectrometer by Jones Calculus in View of both Optical Throughput and Interference Fringe Visibility

NASA Astrophysics Data System (ADS)

Zhang, Xuanni; Zhang, Chunmin

2013-01-01

A polarization interference imaging spectrometer based on Savart polariscope was presented. Its optical throughput was analyzed by Jones calculus. The throughput expression was given, and clearly showed that the optical throughput mainly depended on the intensity of incident light, transmissivity, refractive index and the layout of optical system. The simulation and analysis gave the optimum layout in view of both optical throughput and interference fringe visibility, and verified that the layout of our former design was optimum. The simulation showed that a small deviation from the optimum layout influenced interference fringe visibility little for the optimum one, but influenced severely for others, so a small deviation is admissible in the optimum, and this can mitigate the manufacture difficulty. These results pave the way for further research and engineering design.

A high powered radar interference mitigation technique for communications signal recovery with fpga implementation

DTIC Science & Technology

2017-03-01

2016.7485263.] 14. SUBJECT TERMS parameter estimation; matched- filter detection; QPSK; radar; interference; LSE, cyber, electronic warfare 15. NUMBER OF...signal is routed through a maximum-likelihood detector (MLD), which is a bank of four filters matched to the four symbols of the QPSK constellation... filters matched for each of the QPSK symbols is used to demodulate the signal after cancellation. The matched filters are defined as the complex

Effect of sex, age and genetics on crossover interference in cattle

PubMed Central

Wang, Zhiying; Shen, Botong; Jiang, Jicai; Li, Jinquan; Ma, Li

2016-01-01

Crossovers generated by homologous recombination ensure proper chromosome segregation during meiosis. Crossover interference results in chiasmata being more evenly distributed along chromosomes, but the mechanism underlying crossover interference remains elusive. Based on large pedigrees of Holstein and Jersey cattle with genotype data, we extracted three-generation families, including 147,327 male and 71,687 female meioses in Holstein, and 108,163 male and 37,008 female meioses in Jersey, respectively. We identified crossovers in these meioses and fitted the Housworth-Stahl “interference-escape” model to study crossover interference patterns in the cattle genome. Our result reveals that the degree of crossover interference is stronger in females than in males. We found evidence for inter-chromosomal variation in the level of crossover interference, with smaller chromosomes exhibiting stronger interference. In addition, crossover interference levels decreased with maternal age. Finally, sex-specific GWAS analyses identified one locus near the NEK9 gene on chromosome 10 to have a significant effect on crossover interference levels. This locus has been previously associated with recombination rate in cattle. Collectively, this large-scale analysis provided a comprehensive description of crossover interference across chromosome, sex and age groups, identified associated candidate genes, and produced useful insights into the mechanism of crossover interference. PMID:27892966

Physiologic implications of inter-hormonal interference in fish: lessons from the interaction of adrenaline with cortisol and thyroid hormones in climbing perch (Anabas testudineus Bloch).

PubMed

George, Nimta; Peter, Valsa S; Peter, M C Subhash

2013-01-15

Adrenaline and cortisol, the major stress hormones, are known for its direct control on stress response in fish. Likewise, as an important stress modifier hormone, thyroid hormone has also been implicated in stress response of fish. We tested whether the hypothesis on the phenomenon of inter-hormonal interference, a process that explains the hormonal interactions, operates in fish particularly between adrenaline, cortisol and thyroid hormones. To achieve this goal, indices of acid-base, osmotic and metabolic regulations were quantified after adrenaline challenge in propranolol pre-treated air-breathing fish (Anabas testudineus). Short-term adrenaline (10 ng g(-1)) injection for 30 min produced a rise in plasma cortisol without affecting plasma T(3) and T(4). On the contrary, blocking of adrenaline action with a non-selective blocker, propranolol (25 ng g(-1)) for 90 min reduced plasma cortisol along with plasma T(4) and that indicate a possible interference of these hormones in the absence of adrenaline challenge. Similarly, a reduction in plasma T(3) was found after adrenaline challenge in propranolol pre-treated fish and that suggests a functional synergistic interference of adrenaline with T(3). Adrenaline challenge in these fish, however, failed to abolish this propranolol effect. The remarkable systemic hypercapnia and acidosis by propranolol pre-treatment were reversed by adrenaline challenge, pointing to a direct action of adrenaline on acid-base indices probably by a mechanism which may not require β-adrenergic receptor systems. Interestingly, the prominent adrenaline-induced hyperglycemia, hyperlactemia and hyperuremea were not altered by propranolol treatment. Similarly, adrenaline challenge promoted and propranolol reduced the osmotic competencies of the gills, kidneys and liver of this fish as evident in the sodium and proton pump activities. The modified physiologic actions of adrenaline and its modified interaction with THs and cortisol in blocked fish indicate an interaction of adrenaline with cortisol and THs. Our physiologic evidences thus support the hypothesis of the phenomenon of inter-hormonal interference. Copyright © 2012 Elsevier Inc. All rights reserved.

Blind I/Q imbalance and nonlinear ISI mitigation in Nyquist-SCM direct detection system with cascaded widely linear and Volterra equalizer

NASA Astrophysics Data System (ADS)

Liu, Na; Ju, Cheng

2018-02-01

Nyquist-SCM signal after fiber transmission, direct detection (DD), and analog down-conversion suffers from linear ISI, nonlinear ISI, and I/Q imbalance, simultaneously. Theoretical analysis based on widely linear (WL) and Volterra series is given to explain the relationship and interaction of these three interferences. A blind equalization algorithm, cascaded WL and Volterra equalizer, is designed to mitigate these three interferences. Furthermore, the feasibility of the proposed cascaded algorithm is experimentally demonstrated based on a 40-Gbps data rate 16-quadrature amplitude modulation (QAM) virtual single sideband (VSSB) Nyquist-SCM DD system over 100-km standard single mode fiber (SSMF) transmission. In addition, the performances of conventional strictly linear equalizer, WL equalizer, Volterra equalizer, and cascaded WL and Volterra equalizer are experimentally evaluated, respectively.

Modeling and Measurements for Mitigating Interface from Skyshine

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

Kernan, Warnick J; Mace, Emily K; Siciliano, Edward R

2009-12-21

Skyshine, the radiation scattered in the air above a high-activity gamma-ray source, can produce interference with radiation portal monitor (RPM) systems at distances up to even many hundred meters. Pacific Northwest National Laboratory (PNNL) has been engaged in a campaign of measurements, design work and modeling that explore methods of mitigating the effects of skyshine on outdoor measurements with sensitive instruments. An overview of our work with shielding of skyshine is being reported by us in another paper at this conference. This paper will concentrate on two topics: measurements and modeling with Monte Carlo transport calculations to characterize skyshine frommore » an iridium-192 source, and testing of a prototype louver system, designed and fabricated at PNNL, as a shielding approach to limit the impact of skyshine interference on RPM systems.« less

Dissociating interference-control processes between memory and response.

PubMed

Bissett, Patrick G; Nee, Derek Evan; Jonides, John

2009-09-01

The ability to mitigate interference is of central importance to cognition. Previous research has provided conflicting accounts about whether operations that resolve interference are singular in character or form a family of functions. Here, the authors examined the relationship between interference-resolution processes acting on working memory representations versus responses. The authors combined multiple forms of interference into a single paradigm by merging a directed-forgetting task, which induces proactive interference, with a stop-signal task, which taps response inhibition processes. The results demonstrated that proactive interference and response inhibition produced distinct behavioral signatures that did not interact. By contrast, combining two different measures of response inhibition by merging a go/no-go task variant and a stop signal produced overadditive behavioral interference, demonstrating that different forms of response inhibition tap the same processes. However, not all forms of response conflict interacted, suggesting that inhibition-related functions acting on response selection are dissociable from those acting on response inhibition. These results suggest that inhibition-related functions for memory and responses are dissociable. (c) 2009 APA, all rights reserved.

Mitigation of crosstalk based on CSO-ICA in free space orbital angular momentum multiplexing systems

NASA Astrophysics Data System (ADS)

Xing, Dengke; Liu, Jianfei; Zeng, Xiangye; Lu, Jia; Yi, Ziyao

2018-09-01

Orbital angular momentum (OAM) multiplexing has caused a lot of concerns and researches in recent years because of its great spectral efficiency and many OAM systems in free space channel have been demonstrated. However, due to the existence of atmospheric turbulence, the power of OAM beams will diffuse to beams with neighboring topological charges and inter-mode crosstalk will emerge in these systems, resulting in the system nonavailability in severe cases. In this paper, we introduced independent component analysis (ICA), which is known as a popular method of signal separation, to mitigate inter-mode crosstalk effects; furthermore, aiming at the shortcomings of traditional ICA algorithm's fixed iteration speed, we proposed a joint algorithm, CSO-ICA, to improve the process of solving the separation matrix by taking advantage of fast convergence rate and high convergence precision of chicken swarm algorithm (CSO). We can get the optimal separation matrix by adjusting the step size according to the last iteration in CSO-ICA. Simulation results indicate that the proposed algorithm has a good performance in inter-mode crosstalk mitigation and the optical signal-to-noise ratio (OSNR) requirement of received signals (OAM+2, OAM+4, OAM+6, OAM+8) is reduced about 3.2 dB at bit error ratio (BER) of 3.8 × 10-3. Meanwhile, the convergence speed is much faster than the traditional ICA algorithm by improving about an order of iteration times.

LDPC product coding scheme with extrinsic information for bit patterned media recoding

NASA Astrophysics Data System (ADS)

Jeong, Seongkwon; Lee, Jaejin

2017-05-01

Since the density limit of the current perpendicular magnetic storage system will soon be reached, bit patterned media recording (BPMR) is a promising candidate for the next generation storage system to achieve an areal density beyond 1 Tb/in2. Each recording bit is stored in a fabricated magnetic island and the space between the magnetic islands is nonmagnetic in BPMR. To approach recording densities of 1 Tb/in2, the spacing of the magnetic islands must be less than 25 nm. Consequently, severe inter-symbol interference (ISI) and inter-track interference (ITI) occur. ITI and ISI degrade the performance of BPMR. In this paper, we propose a low-density parity check (LDPC) product coding scheme that exploits extrinsic information for BPMR. This scheme shows an improved bit error rate performance compared to that in which one LDPC code is used.

Coherent detection of position errors in inter-satellite laser communications

NASA Astrophysics Data System (ADS)

Xu, Nan; Liu, Liren; Liu, De'an; Sun, Jianfeng; Luan, Zhu

2007-09-01

Due to the improved receiver sensitivity and wavelength selectivity, coherent detection became an attractive alternative to direct detection in inter-satellite laser communications. A novel method to coherent detection of position errors information is proposed. Coherent communication system generally consists of receive telescope, local oscillator, optical hybrid, photoelectric detector and optical phase lock loop (OPLL). Based on the system composing, this method adds CCD and computer as position error detector. CCD captures interference pattern while detection of transmission data from the transmitter laser. After processed and analyzed by computer, target position information is obtained from characteristic parameter of the interference pattern. The position errors as the control signal of PAT subsystem drive the receiver telescope to keep tracking to the target. Theoretical deviation and analysis is presented. The application extends to coherent laser rang finder, in which object distance and position information can be obtained simultaneously.

47 CFR 95.405 - (CB Rule 5) Where may I operate my CB station?

Code of Federal Regulations, 2011 CFR

2011-10-01

... SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Citizens Band (CB) Radio Service General Provisions § 95... mitigate any potential interference problem with the Arecibo Observatory. If the Commission determines that...

47 CFR 95.405 - (CB Rule 5) Where may I operate my CB station?

Code of Federal Regulations, 2010 CFR

2010-10-01

... SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Citizens Band (CB) Radio Service General Provisions § 95... mitigate any potential interference problem with the Arecibo Observatory. If the Commission determines that...

Apodized RFI filtering of synthetic aperture radar images

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

Doerry, Armin Walter

2014-02-01

Fine resolution Synthetic Aperture Radar (SAR) systems necessarily require wide bandwidths that often overlap spectrum utilized by other wireless services. These other emitters pose a source of Radio Frequency Interference (RFI) to the SAR echo signals that degrades SAR image quality. Filtering, or excising, the offending spectral contaminants will mitigate the interference, but at a cost of often degrading the SAR image in other ways, notably by raising offensive sidelobe levels. This report proposes borrowing an idea from nonlinear sidelobe apodization techniques to suppress interference without the attendant increase in sidelobe levels. The simple post-processing technique is termed Apodized RFImore » Filtering (ARF).« less

Ant Colony Optimization Algorithm for Centralized Dynamic Channel Allocation in Multi-Cell OFDMA Systems

NASA Astrophysics Data System (ADS)

Kim, Hyo-Su; Kim, Dong-Hoi

The dynamic channel allocation (DCA) scheme in multi-cell systems causes serious inter-cell interference (ICI) problem to some existing calls when channels for new calls are allocated. Such a problem can be addressed by advanced centralized DCA design that is able to minimize ICI. Thus, in this paper, a centralized DCA is developed for the downlink of multi-cell orthogonal frequency division multiple access (OFDMA) systems with full spectral reuse. However, in practice, as the search space of channel assignment for centralized DCA scheme in multi-cell systems grows exponentially with the increase of the number of required calls, channels, and cells, it becomes an NP-hard problem and is currently too complicated to find an optimum channel allocation. In this paper, we propose an ant colony optimization (ACO) based DCA scheme using a low-complexity ACO algorithm which is a kind of heuristic algorithm in order to solve the aforementioned problem. Simulation results demonstrate significant performance improvements compared to the existing schemes in terms of the grade of service (GoS) performance and the forced termination probability of existing calls without degrading the system performance of the average throughput.

Enhanced intercarrier interference mitigation based on encoded bit-sequence distribution inside optical superchannels

NASA Astrophysics Data System (ADS)

Torres, Jhon James Granada; Soto, Ana María Cárdenas; González, Neil Guerrero

2016-10-01

In the context of gridless optical multicarrier systems, we propose a method for intercarrier interference (ICI) mitigation which allows bit error correction in scenarios of nonspectral flatness between the subcarriers composing the multicarrier system and sub-Nyquist carrier spacing. We propose a hybrid ICI mitigation technique which exploits the advantages of signal equalization at both levels: the physical level for any digital and analog pulse shaping, and the bit-data level and its ability to incorporate advanced correcting codes. The concatenation of these two complementary techniques consists of a nondata-aided equalizer applied to each optical subcarrier, and a hard-decision forward error correction applied to the sequence of bits distributed along the optical subcarriers regardless of prior subchannel quality assessment as performed in orthogonal frequency-division multiplexing modulations for the implementation of the bit-loading technique. The impact of the ICI is systematically evaluated in terms of bit-error-rate as a function of the carrier frequency spacing and the roll-off factor of the digital pulse-shaping filter for a simulated 3×32-Gbaud single-polarization quadrature phase shift keying Nyquist-wavelength division multiplexing system. After the ICI mitigation, a back-to-back error-free decoding was obtained for sub-Nyquist carrier spacings of 28.5 and 30 GHz and roll-off values of 0.1 and 0.4, respectively.

Neural mechanisms of proactive interference-resolution.

PubMed

Nee, Derek Evan; Jonides, John; Berman, Marc G

2007-12-01

The ability to mitigate interference from information that was previously relevant, but is no longer relevant, is central to successful cognition. Several studies have implicated left ventrolateral prefrontal cortex (VLPFC) as a region tied to this ability, but it is unclear whether this result generalizes across different tasks. In addition, it has been suggested that left anterior prefrontal cortex (APFC) also plays a role in proactive interference-resolution although support for this claim has been limited. The present study used event-related functional magnetic resonance imaging (fMRI) to investigate the role of these regions in resolving proactive-interference across two different tasks performed on the same subjects. Results indicate that both left VLPFC and left APFC are involved in the resolution of proactive interference across tasks. However, different functional networks related to each region suggest dissociable roles for the two regions. Additionally, regions of the posterior cingulate gyrus demonstrated unique involvement in facilitation when short- and long-term memory converged. This pattern of results serves to further specify models of proactive interference-resolution.

Real-Time RFI Mitigation in Pulsar Observations

NASA Astrophysics Data System (ADS)

Ramey, Emily; Joslyn, Nick; Prestage, Richard; Whitehead, Mark; Lam, Michael Timothy; Blattner, Tim; Hawkins, Luke; Viou, Cedric; Masson, Jessica

2018-01-01

As the use of wireless technology has increased around the world, Radio Frequency Interference (RFI) has become more and more of a problem for radio astronomers. Preventative measures exist to limit the presence of RFI, and programs exist to remove it from saved data, but the routine use of algorithms to detect and remove RFI as an observation is occurring is much less common. Such a method would be incredibly useful for observations in which the data must undergo several rounds of processing before being saved, as in pulsar timing studies. Strategies for real-time mitigation have been discussed and tested with simulated data (Buch et al., 2016), but ideally the results of any approach would be validated by a detailed comparison of the final data products - for pulsar timing, the variance in the pulse times of arrival (TOAs) - with and without mitigation applied. The goal of this project is to develop an RFI mitigation approach based on the previously suggested strategies and test this program on actual data from the observation of pulsar J1713+0747. We use a Median Absolute Deviation (MAD) filter to identify interference in the observation and replace the compromised data with random Gaussian noise to match a characteristic radio signal from space. In order to verify our results, we analyze the pulsar’s TOAs obtained both from the mitigated data and from the unmitigated data processed through offline RFI removal software. Comparing the two, our preliminary findings indicate that our program is able to improve the quality of timing results from the observation.

Mitigation of time-varying distortions in Nyquist-WDM systems using machine learning

NASA Astrophysics Data System (ADS)

Granada Torres, Jhon J.; Varughese, Siddharth; Thomas, Varghese A.; Chiuchiarelli, Andrea; Ralph, Stephen E.; Cárdenas Soto, Ana M.; Guerrero González, Neil

2017-11-01

We propose a machine learning-based nonsymmetrical demodulation technique relying on clustering to mitigate time-varying distortions derived from several impairments such as IQ imbalance, bias drift, phase noise and interchannel interference. Experimental results show that those impairments cause centroid movements in the received constellations seen in time-windows of 10k symbols in controlled scenarios. In our demodulation technique, the k-means algorithm iteratively identifies the cluster centroids in the constellation of the received symbols in short time windows by means of the optimization of decision thresholds for a minimum BER. We experimentally verified the effectiveness of this computationally efficient technique in multicarrier 16QAM Nyquist-WDM systems over 270 km links. Our nonsymmetrical demodulation technique outperforms the conventional QAM demodulation technique, reducing the OSNR requirement up to ∼0.8 dB at a BER of 1 × 10-2 for signals affected by interchannel interference.

Analysis of RFI Statistics for Aquarius RFI Detection and Mitigation Improvements

NASA Technical Reports Server (NTRS)

de Matthaeis, Paolo; Soldo, Yan; Le Vine, David M.

2016-01-01

Aquarius is an L-band active/passive sensor designed to globally map sea surface salinity from space. Two instruments, a radar scatterometer and a radiometer, observe the same surface footprint almost simultaneously. The radiometer is the primary instrument for sensing sea surface salinity (SSS), while the scatterometer is included to provide a correction for sea surface roughness, which is a primary source of error in the salinity retrieval. Although the primary objective is the measurement of SSS, the instrument combination operates continuously, acquiring data over land and sea ice as well. An important feature of the data processing includes detection and mitigation of Radio Frequency Interference (RFI) which is done separately for both active and passive instruments. Correcting for RFI is particularly critical over ocean because of the high accuracy required in the brightness temperature measurements for SSS retrieval. It is also necessary for applications of the Aquarius data over land, where man-made interference is widespread, even though less accuracy is required in this case. This paper will provide an overview of the current status of the Aquarius RFI processing and an update on the ongoing work on the improvement of the RFI detection and mitigation performance.

Radio Frequency Interference Detection and Mitigation Techniques Using Data from Ecosar 2014 Flight Campaign

NASA Technical Reports Server (NTRS)

Osmanoglu, Batuhan; Rincon, Rafael F.; Lee, SeungKuk; Fatoyinb, Temilola; Bollian, Tobias

2016-01-01

Radio frequency interference (RFI) has strong influence on wide band airborne radar systems, especially operaingat L-band (1-2 GHz) or lower frequencies. EcoSAR is a P-band digital beamforming radar system, and RFI has tobe removed from raw echoes to obtain science quality data. In this paper we describe the current methodologyused to tackle RFI with EcoSAR, and provide an example on its performance. Finally, we discuss the advantagesand disadvantages of the method and mention potential improvements.

Subarray Processing for Projection-based RFI Mitigation in Radio Astronomical Interferometers

NASA Astrophysics Data System (ADS)

Burnett, Mitchell C.; Jeffs, Brian D.; Black, Richard A.; Warnick, Karl F.

2018-04-01

Radio Frequency Interference (RFI) is a major problem for observations in Radio Astronomy (RA). Adaptive spatial filtering techniques such as subspace projection are promising candidates for RFI mitigation; however, for radio interferometric imaging arrays, these have primarily been used in engineering demonstration experiments rather than mainstream scientific observations. This paper considers one reason that adoption of such algorithms is limited: RFI decorrelates across the interferometric array because of long baseline lengths. This occurs when the relative RFI time delay along a baseline is large compared to the frequency channel inverse bandwidth used in the processing chain. Maximum achievable excision of the RFI is limited by covariance matrix estimation error when identifying interference subspace parameters, and decorrelation of the RFI introduces errors that corrupt the subspace estimate, rendering subspace projection ineffective over the entire array. In this work, we present an algorithm that overcomes this challenge of decorrelation by applying subspace projection via subarray processing (SP-SAP). Each subarray is designed to have a set of elements with high mutual correlation in the interferer for better estimation of subspace parameters. In an RFI simulation scenario for the proposed ngVLA interferometric imaging array with 15 kHz channel bandwidth for correlator processing, we show that compared to the former approach of applying subspace projection on the full array, SP-SAP improves mitigation of the RFI on the order of 9 dB. An example of improved image synthesis and reduced RFI artifacts for a simulated image “phantom” using the SP-SAP algorithm is presented.

Nutrient loads exported from managed catchments reveal emergent biogeochemical stationarity

NASA Astrophysics Data System (ADS)

Basu, Nandita B.; Destouni, Georgia; Jawitz, James W.; Thompson, Sally E.; Loukinova, Natalia V.; Darracq, Amélie; Zanardo, Stefano; Yaeger, Mary; Sivapalan, Murugesu; Rinaldo, Andrea; Rao, P. Suresh C.

2010-12-01

Complexity of heterogeneous catchments poses challenges in predicting biogeochemical responses to human alterations and stochastic hydro-climatic drivers. Human interferences and climate change may have contributed to the demise of hydrologic stationarity, but our synthesis of a large body of observational data suggests that anthropogenic impacts have also resulted in the emergence of effective biogeochemical stationarity in managed catchments. Long-term monitoring data from the Mississippi-Atchafalaya River Basin (MARB) and the Baltic Sea Drainage Basin (BSDB) reveal that inter-annual variations in loads (LT) for total-N (TN) and total-P (TP), exported from a catchment are dominantly controlled by discharge (QT) leading inevitably to temporal invariance of the annual, flow-weighted concentration, $\\overline{Cf = (LT/QT). Emergence of this consistent pattern across diverse managed catchments is attributed to the anthropogenic legacy of accumulated nutrient sources generating memory, similar to ubiquitously present sources for geogenic constituents that also exhibit a linear LT-QT relationship. These responses are characteristic of transport-limited systems. In contrast, in the absence of legacy sources in less-managed catchments, $\\overline{Cf values were highly variable and supply limited. We offer a theoretical explanation for the observed patterns at the event scale, and extend it to consider the stochastic nature of rainfall/flow patterns at annual scales. Our analysis suggests that: (1) expected inter-annual variations in LT can be robustly predicted given discharge variations arising from hydro-climatic or anthropogenic forcing, and (2) water-quality problems in receiving inland and coastal waters would persist until the accumulated storages of nutrients have been substantially depleted. The finding has notable implications on catchment management to mitigate adverse water-quality impacts, and on acceleration of global biogeochemical cycles.

Spatial and Temporal Patterns of SMAP Brightness Temperatures for Use in Level 1 TB Characterization

NASA Astrophysics Data System (ADS)

Kim, E. J.

2015-12-01

1. IntroductionThe recent launch of NASA's Soil Moisture Active Passive (SMAP) mission [Entekhabi, et al] has opened the door to improved brightness temperature (TB) calibration of satellite L-band microwave radiometers, through the use of SMAP's lower noise performance and better immunity to man-made interference (vs. ESA's Soil Moisture Ocean Salinity (SMOS) mission [Kerr, et al]), better spatial resolution (vs. NASA's Aquarius sea surface salinity mission [Le Vine, et al]), and cleaner antenna pattern (vs. SMOS). All three radiometers use/used large homogeneous places on Earth's surface as calibration targets—parts of the ocean, Antarctica, and tropical forests. Despite the recent loss of Aquarius data, there is still hope for creating a longer-term L-band data set that spans the timeframe of all 3 missions. 2. Description of Analyses and Expected Results In this paper, we analyze SMAP brightness temperature data to quantify the spatial and temporal characteristics of external target areas in the oceans, Antarctica, forests, and other areas. Existing analyses have examined these targets in terms of averages, standard deviations, and other basic statistics (for Aquarius & SMOS as well). This paper will approach the problem from a signal processing perspective. Coupled with the use of SMAP's novel RFI-mitigated TBs, and the aforementioned lower noise and cleaner antenna pattern, it is expected that of the 3 L-band missions, SMAP should do the best job of characterizing such external targets. The resulting conclusions should be useful to extract the best possible TB calibration from all 3 missions, helping to inter-compare the TB from the 3 missions, and to eventually inter-calibrate the TBs into a single long-term dataset.

High resolution ID-ICP-MS certification of an estuary water reference material (LGC 6016) and analysis of matrix induced polyatomic interferences.

PubMed

Evans, P; Fairman, B

2001-10-01

Reliable trace metal analysis of environmental samples is dependent upon the availability of high accuracy, matrix reference standards. Here, we present Cd, Cu, Ni, Pb and Zn isotope dilution determination for an estuary water certified reference material (LGC 6016). This work highlights the need for high-accuracy techniques in the development of trace element CRMs rather than conventional inter-laboratory trials. Certification of the estuary water LGC6016 was initially determined from a consensus mean from 14 laboratories but this was found to be unsatisfactory due to the large discrepancies in the reported concentrations. The material was re-analysed using isotope dilution ICP-MS techniques. Pb and Cd were determined using a conventional quadrupole ICP-MS (Elan 5000). Cu, Zn and Ni were determined using a magnetic sector ICP-MS (Finnigan Element), which allowed significant polyatomic interferences to be overcome. Using the magnetic sector instrument, precise mass calibration to within 0.02 amu permitted identification of the interferences. Most interferences derived from the sample matrix. For example, the high Na content causes interferences on 63Cu, due to the formation of 40Ar23Na and 23Na2 16O1H, which in a conventional quadrupole instrument would relate to an erroneous increase in signal intensity by up to 20%. For each analyte a combined uncertainty calculation was performed following the Eurachem/GTAC and ISO guideline. For each element a combined uncertainty of 2-3% was found, which represents a 10-fold improvement compared to certification by inter-laboratory comparison. Analysis of the combined uncertainty budget indicates that the majority of systematic uncertainty derives from the instrumental isotope ratio measurements.

50 CFR 216.174 - Mitigation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... operation (including aircraft, surface ships, or submarines) shall monitor for marine mammal vocalizations... mammals. (xvii) Navy aircraft participating in exercises at sea shall conduct and maintain, when... constraints or interfere with the accomplishment of primary operational duties. (xviii) Aircraft with deployed...

50 CFR 216.174 - Mitigation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... operation (including aircraft, surface ships, or submarines) shall monitor for marine mammal vocalizations... mammals. (xvii) Navy aircraft participating in exercises at sea shall conduct and maintain, when... constraints or interfere with the accomplishment of primary operational duties. (xviii) Aircraft with deployed...

50 CFR 216.174 - Mitigation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... operation (including aircraft, surface ships, or submarines) shall monitor for marine mammal vocalizations... mammals. (xvii) Navy aircraft participating in exercises at sea shall conduct and maintain, when... constraints or interfere with the accomplishment of primary operational duties. (xviii) Aircraft with deployed...

76 FR 34230 - Sunshine Act Meeting; Deletion of Agenda Item from June 9, 2011 Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-13

... mitigate space path interference between the 17/24 GHz Broadcasting-Satellite Service (BSS) space stations and current and future Direct Broadcasting Service (DBS) space stations that operate in the same...

Adaptive limited feedback for interference alignment in MIMO interference channels.

PubMed

Zhang, Yang; Zhao, Chenglin; Meng, Juan; Li, Shibao; Li, Li

2016-01-01

It is very important that the radar sensor network has autonomous capabilities such as self-managing, etc. Quite often, MIMO interference channels are applied to radar sensor networks, and for self-managing purpose, interference management in MIMO interference channels is critical. Interference alignment (IA) has the potential to dramatically improve system throughput by effectively mitigating interference in multi-user networks at high signal-to-noise (SNR). However, the implementation of IA predominantly relays on perfect and global channel state information (CSI) at all transceivers. A large amount of CSI has to be fed back to all transmitters, resulting in a proliferation of feedback bits. Thus, IA with limited feedback has been introduced to reduce the sum feedback overhead. In this paper, by exploiting the advantage of heterogeneous path loss, we first investigate the throughput of IA with limited feedback in interference channels while each user transmits multi-streams simultaneously, then we get the upper bound of sum rate in terms of the transmit power and feedback bits. Moreover, we propose a dynamic feedback scheme via bit allocation to reduce the throughput loss due to limited feedback. Simulation results demonstrate that the dynamic feedback scheme achieves better performance in terms of sum rate.

Patterns of light interference produced by damaged cuticle cells in human hair.

PubMed

Gamez-Garcia, Manuel; Lu, Yuan

2007-01-01

Colorful patterns of light interference have been observed to occur in human hair cuticle cells. The light interference phenomenon has been analyzed by optical microscopy. The strong patterns of light interference appeared only in cuticle cells that had been damaged either mechanically or by thermal stresses. Cuticle cells that were not damaged did not produce this phenomenon. The zones of light interference on the hair surface were seen to extend to cuticle sheath areas whose damage was not apparent when analyzed under the Scanning Electron Microscope. The presence of oils and other hydrophobic materials in the hair had a strong effect in the appearance or disappearance of the interference patterns.

L Band Service Compatibility : Part II: Optimum GPS Receiver ABI Compatibility

DOT National Transportation Integrated Search

2015-03-12

Workshop Objectives. This is the Second of Two Parts on Compatibility. Last time, OOBE. Today examine mitigation of Adjacent Band Interference, ABI. Apply Relevant TWG and NPEF (2011) data to engage compatibility analysis. Assert Principle: Dr. Brad ...

Wiener filter preprocessing for OFDM systems in the presence of both nonstationary and stationary phase noises

NASA Astrophysics Data System (ADS)

Zhong, Ke; Lei, Xia; Li, Shaoqian

2013-12-01

Statistics-based intercarrier interference (ICI) mitigation algorithm is proposed for orthogonal frequency division multiplexing systems in presence of both nonstationary and stationary phase noises. By utilizing the statistics of phase noise, which can be obtained from measurements or data sheets, a Wiener filter preprocessing algorithm for ICI mitigation is proposed. The proposed algorithm can be regarded as a performance-improving technique for the previous researches on phase noise cancelation. Simulation results show that the proposed algorithm can effectively mitigate ICI and lower the error floor, and therefore significantly improve the performances of previous researches on phase noise cancelation, especially in the presence of severe phase noise.

Challenge Integrity: The Cell-Penetrating Peptide BP100 Interferes with the Auxin-Actin Oscillator.

PubMed

Eggenberger, Kai; Sanyal, Papia; Hundt, Svenja; Wadhwani, Parvesh; Ulrich, Anne S; Nick, Peter

2017-01-01

Actin filaments are essential for the integrity of the cell membrane. In addition to this structural role, actin can modulate signaling by altering polar auxin flow. On the other hand, the organization of actin filaments is modulated by auxin constituting a self-referring signaling hub. Although the function of this auxin–actin oscillator is not clear, there is evidence for a functional link with stress signaling activated by the NADPH oxidase Respiratory burst oxidase Homolog (RboH). In the current work, we used the cell-penetrating peptide BP100 to induce a mild and transient perturbation of membrane integrity. We followed the response of actin to the BP100 uptake in a green fluorescent protein (GFP)-tagged actin marker line of tobacco Bright Yellow 2 (BY-2) cells by spinning disc confocal microscopy. We observed that BP100 enters in a stepwise manner and reduces the extent of actin remodeling. This actin ‘freezing’ can be rescued by the natural auxin IAA, and mimicked by the auxin-efflux inhibitor 1-napthylphthalamic acid (NPA). We further tested the role of the membrane-localized NADPH oxidase RboH using the specific inhibitor diphenyl iodonium (DPI), and found that DPI acts antagonistically to BP100, although DPI alone can induce a similar actin ‘freezing’ as well. We propose a working model, where the mild violation of membrane integrity by BP100 stimulates RboH, and the resulting elevated levels of reactive oxygen species interfere with actin dynamicity. The mitigating effect of auxin is explained by competition of auxin- and RboH-triggered signaling for superoxide anions. This self-referring auxin–actin–RboH hub might be essential for integrity sensing.

Mesenchymal Stromal Cells Disrupt mTOR-Signaling and Aerobic Glycolysis During T-Cell Activation.

PubMed

Böttcher, Martin; Hofmann, Andreas D; Bruns, Heiko; Haibach, Martina; Loschinski, Romy; Saul, Domenica; Mackensen, Andreas; Le Blanc, Katarina; Jitschin, Regina; Mougiakakos, Dimitrios

2016-02-01

Mesenchymal stromal cells (MSCs) possess numerous regenerative and immune modulating functions. Transplantation across histocompatibility barriers is feasible due to their hypo-immunogenicity. MSCs have emerged as promising tools for treating graft-versus-host disease following allogeneic stem cell transplantation. It is well established that their clinical efficacy is substantially attributed to fine-tuning of T-cell responses. At the same time, increasing evidence suggests that metabolic processes control T-cell function and fate. Here, we investigated the MSCs' impact on the metabolic framework of activated T-cells. In fact, MSCs led to mitigated mTOR signaling. This phenomenon was accompanied by a weaker glycolytic response (including glucose uptake, glycolytic rate, and upregulation of glycolytic machinery) toward T-cell activating stimuli. Notably, MSCs express indoleamine-2,3-dioxygenase (IDO), which mediates T-cell suppressive tryptophan catabolism. Our observations suggest that IDO-induced tryptophan depletion interferes with a tryptophan-sufficiency signal that promotes cellular mTOR activation. Despite an immediate suppression of T-cell responses, MSCs foster a metabolically quiescent T-cell phenotype characterized by reduced mTOR signaling and glycolysis, increased autophagy, and lower oxidative stress levels. In fact, those features have previously been shown to promote generation of long-lived memory cells and it remains to be elucidated how MSC-induced metabolic effects shape in vivo T-cell immunity. © 2015 AlphaMed Press.

How CO2 Leakage May Impact the Role of Geologic Carbon Storage in Climate Mitigation

NASA Astrophysics Data System (ADS)

Peters, C. A.; Deng, H.; Bielicki, J. M.; Fitts, J. P.; Oppenheimer, M.

2014-12-01

Among CCUS technologies (Carbon Capture Utilization and Sequestration), geological storage of CO2 has a large potential to mitigate greenhouse gas emissions, but confidence in its deployment is often clouded by the possibility and cost of leakage. In this study, we took the Michigan sedimentary basin as an example to investigate the monetized risks associated with leakage, using the Risk Interference of Subsurface CO2 Storage (RISCS) model. The model accounts for spatial heterogeneity and variability of hydraulic properties of the subsurface system and permeability of potential leaking wells. In terms of costs, the model quantifies the financial consequences of CO2 escaping back to the atmosphere as well as the costs incurred if CO2 or brine leaks into overlying formations and interferes with other subsurface activities or resources. The monetized leakage risks derived from the RISCS model were then used to modify existing cost curves by shifting them upwards and changing their curvatures. The modified cost curves were used in the integrated assessment model - GCAM (Global Change Assessment Model), which provides policy-relevant results to help inform the potential role of CCUS in future energy systems when carbon mitigation targets and incentives are in place. The results showed that the extent of leakage risks has a significant effect on the extent of CCUS deployment. Under more stringent carbon mitigation policies such as a high carbon tax, higher leakage risks can be afforded and incorporating leakage risks will have a smaller impact on CCUS deployment. Alternatively, if the leakage risks were accounted for by charging a fixed premium, similar to how the risk of nuclear waste disposal is treated, the contribution of CCUS in mitigating climate change varies, depending on the value of the premium.

Discovery, identification and mitigation of isobaric sulfate metabolite interference to a phosphate prodrug in LC-MS/MS bioanalysis: Critical role of method development in ensuring assay quality.

PubMed

Yuan, Long; Ji, Qin C

2018-06-05

Metabolite interferences represent a major risk of inaccurate quantification when using LC-MS/MS bioanalytical assays. During LC-MS/MS bioanalysis of BMS-919194, a phosphate ester prodrug, in plasma samples from rat and monkey GLP toxicology studies, an unknown peak was detected in the MRM channel of the prodrug. This peak was not observed in previous discovery toxicology studies, in which a fast gradient LC-MS/MS method was used. We found out that this unknown peak would co-elute with the prodrug peak when the discovery method was used, therefore, causing significant overestimation of the exposure of the prodrug in the discovery toxicology studies. To understand the nature of this interfering peak and its impact to bioanalytical assay, we further investigated its formation and identification. The interfering compound and the prodrug were found to be isobaric and to have the same major product ions in electrospray ionization positive mode, thus, could not be differentiated using a triple quadrupole mass spectrometer. By using high-resolution mass spectrometry (HRMS), the interfering metabolite was successfully identified to be an isobaric sulfate metabolite of BMS-919194. To the best of our knowledge, this is the first report that a phosphate prodrug was metabolized in vivo to an isobaric sulfate metabolite, and this metabolite caused significant interference to the analysis of the prodrug. This work demonstrated the presence of the interference risk from isobaric sulfate metabolites to the bioanalysis of phosphate prodrugs in real samples. It is critical to evaluate and mitigate potential metabolite interferences during method development, therefore, minimize the related bioanalytical risks and ensure assay quality. Our work also showed the unique advantages of HRMS in identifying potential metabolite interference during LC-MS/MS bioanalysis. Copyright © 2018 Elsevier B.V. All rights reserved.

37 CFR 2.120 - Discovery.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Discovery. 2.120 Section 2... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Procedure in Inter Partes Proceedings § 2.120 Discovery. (a... to disclosure and discovery shall apply in opposition, cancellation, interference and concurrent use...

37 CFR 2.120 - Discovery.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Discovery. 2.120 Section 2... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Procedure in Inter Partes Proceedings § 2.120 Discovery. (a... to disclosure and discovery shall apply in opposition, cancellation, interference and concurrent use...

37 CFR 2.120 - Discovery.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Discovery. 2.120 Section 2... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Procedure in Inter Partes Proceedings § 2.120 Discovery. (a... to disclosure and discovery shall apply in opposition, cancellation, interference and concurrent use...

37 CFR 2.120 - Discovery.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Discovery. 2.120 Section 2... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Procedure in Inter Partes Proceedings § 2.120 Discovery. (a... to disclosure and discovery shall apply in opposition, cancellation, interference and concurrent use...

37 CFR 2.120 - Discovery.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Discovery. 2.120 Section 2... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Procedure in Inter Partes Proceedings § 2.120 Discovery. (a... to disclosure and discovery shall apply in opposition, cancellation, interference and concurrent use...

Iterative decoding of SOVA and LDPC product code for bit-patterned media recoding

NASA Astrophysics Data System (ADS)

Jeong, Seongkwon; Lee, Jaejin

2018-05-01

The demand for high-density storage systems has increased due to the exponential growth of data. Bit-patterned media recording (BPMR) is one of the promising technologies to achieve the density of 1Tbit/in2 and higher. To increase the areal density in BPMR, the spacing between islands needs to be reduced, yet this aggravates inter-symbol interference and inter-track interference and degrades the bit error rate performance. In this paper, we propose a decision feedback scheme using low-density parity check (LDPC) product code for BPMR. This scheme can improve the decoding performance using an iterative approach with extrinsic information and log-likelihood ratio value between iterative soft output Viterbi algorithm and LDPC product code. Simulation results show that the proposed LDPC product code can offer 1.8dB and 2.3dB gains over the one LDPC code at the density of 2.5 and 3 Tb/in2, respectively, when bit error rate is 10-6.

47 CFR 95.1303 - Authorized locations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Authorized locations. 95.1303 Section 95.1303 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... efforts in order to resolve or mitigate any potential interference problem with the Arecibo Observatory...

47 CFR 95.1303 - Authorized locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Authorized locations. 95.1303 Section 95.1303 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... efforts in order to resolve or mitigate any potential interference problem with the Arecibo Observatory...

47 CFR 95.1003 - Authorized locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Authorized locations. 95.1003 Section 95.1003 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... reasonable efforts in order to resolve or mitigate any potential interference problem with the Arecibo...

47 CFR 95.1003 - Authorized locations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Authorized locations. 95.1003 Section 95.1003 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO... reasonable efforts in order to resolve or mitigate any potential interference problem with the Arecibo...

L Band Service Compatibility Part I: Optimum OOBE Compatibility

DOT National Transportation Integrated Search

2014-12-04

Discussion: -- Two Parts - Today we focus on optimum L Band ABC Out of Band Emission into GPS L1, OOBE. - Next ABC meeting will examine GPS-side mitigation of Adjacent Band Interference, ABI. -- Greater Compatibility: OOBE and ABI are distinct but pa...

Assisted entry mitigates text messaging-based driving detriment.

PubMed

Sawyer, Benjamin D; Hancock, Peter A

2012-01-01

Previous research using cell phones indicates that manual manipulation is not a principal component of text messaging relating driving detriment. This paper suggests that manipulation of a phone in conjunction with the cognitive need to compose the message itself co-act to contribute to driving degradation. This being so, drivers sending text messages might experience reduced interference to the driving task if the text messaging itself were assisted through the predictive T9 system. We evaluated undergraduate drivers in a simulator who drove and texted using either Assisted Text entry, via Nokia's T9 system, or unassisted entry via the multitap interface. Results supported the superiority of the T9 system over the multitap system implying that specific assistive technologies can modulate the degradation of capacity which texting tragically induces.

SAPT units turn-on in an interference-dominant environment. [Stand Alone Pressure Transducer

NASA Technical Reports Server (NTRS)

Peng, W.-C.; Yang, C.-C.; Lichtenberg, C.

1990-01-01

A stand alone pressure transducer (SAPT) is a credit-card-sized smart pressure sensor inserted between the tile and the aluminum skin of a space shuttle. Reliably initiating the SAPT units via RF signals in a prelaunch environment is a challenging problem. Multiple-source interference may exist if more than one GSE (ground support equipment) antenna is turned on at the same time to meet the simultaneity requirement of 10 ms. A polygon model for orbiter, external tank, solid rocket booster, and tail service masts is used to simulate the prelaunch environment. Geometric optics is then applied to identify the coverage areas and the areas which are vulnerable to multipath and/or multiple-source interference. Simulation results show that the underside areas of an orbiter have incidence angles exceeding 80 deg. For multipath interference, both sides of the cargo bay areas are found to be vulnerable to a worst-case multipath loss exceeding 20 dB. Multiple-source interference areas are also identified. Mitigation methods for the coverage and interference problem are described. It is shown that multiple-source interference can be eliminated (or controlled) using the time-division-multiplexing method or the time-stamp approach.

Self-selected music-induced reduction of perceived exertion during moderate-intensity exercise does not interfere with post-exercise improvements in inhibitory control.

PubMed

Tanaka, Daichi; Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Hamaoka, Takafumi; Hashimoto, Takeshi; Isaka, Tadao

2018-05-26

Acute aerobic exercise improves inhibitory control (IC). This improvement is often associated with increases in perceived exertion during exercise. However, listening to music during aerobic exercise mitigates an exercise-induced increase in perceived exertion. Thus, it is hypothesized that such effects of music may interfere with exercise-induced improvements in IC. To test this hypothesis, we examined the effect of music on post-exercise IC improvements that were induced by moderate-intensity exercise. Fifteen healthy young men performed cycle ergometer exercise with music or non-music. The exercise was performed using a moderate-intensity of 60% of VO 2 peak for 30 min. The music condition was performed while listening to self-selected music. The non-music condition involved no music. To evaluate IC, the Stroop task was administered before exercise, immediately after exercise, and during the 30-min post-exercise recovery period. The rate of perceived exertion immediately before moderate-intensity exercise completed was significantly lower in music condition than in non-music condition. The IC significantly improved immediately after exercise and during the post-exercise recovery period compared to before exercise in both music and non-music conditions. The post-exercise IC improvements did not significantly differ between the two conditions. These findings indicate that self-selected music-induced mitigation of the increase in perceived exertion during moderate-intensity exercise dose not interfere with exercise-induced improvements in IC. Therefore, we suggest that listening to music may be a beneficial strategy in mitigating the increase in perceived exertion during aerobic exercise without decreasing the positive effects on IC. Copyright © 2018 Elsevier Inc. All rights reserved.

Investigation of material improvements to mitigate the abrasive wear mechanism of concrete crosstie rail seat deterioration (RSD).

DOT National Transportation Integrated Search

2014-11-01

To meet the increasingly stringent design and performance requirements due to increasing cumulative : gross tonnages from heavy-haul freight operations, along with increased high-speed inter-city passenger : rail development, improvements in concrete...

Laser Frequency Noise in Coherent Optical Systems: Spectral Regimes and Impairments.

PubMed

Kakkar, Aditya; Rodrigo Navarro, Jaime; Schatz, Richard; Pang, Xiaodan; Ozolins, Oskars; Udalcovs, Aleksejs; Louchet, Hadrien; Popov, Sergei; Jacobsen, Gunnar

2017-04-12

Coherent communication networks are based on the ability to use multiple dimensions of the lightwave together with electrical domain compensation of transmission impairments. Electrical-domain dispersion compensation (EDC) provides many advantages such as network flexibility and enhanced fiber nonlinearity tolerance, but makes the system more susceptible to laser frequency noise (FN), e.g. to the local oscillator FN in systems with post-reception EDC. Although this problem has been extensively studied, statistically, for links assuming lasers with white-FN, many questions remain unanswered. Particularly, the influence of a realistic non-white FN-spectrum due to e.g., the presence of 1/f-flicker and carrier induced noise remains elusive and a statistical analysis becomes insufficient. Here we provide an experimentally validated theory for coherent optical links with lasers having general non-white FN-spectrum and EDC. The fundamental reason of the increased susceptibility is shown to be FN-induced symbol displacement that causes timing jitter and/or inter/intra symbol interference. We establish that different regimes of the laser FN-spectrum cause a different set of impairments. The influence of the impairments due to some regimes can be reduced by optimizing the corresponding mitigation algorithms, while other regimes cause irretrievable impairments. Theoretical boundaries of these regimes and corresponding criteria applicable to system/laser design are provided.

Contaminant Interferences with SIMS Analyses of Microparticle Impactor Residues on LDEF Surfaces

NASA Technical Reports Server (NTRS)

Simon, C. G.; Batchelor, D.; Griffis, D. P.; Hunter, J. L.; Misra, V.; Ricks, D. A.; Wortman, J. J.

1992-01-01

Elemental analyses of impactor residues on high purity surface exposed to the low earth orbit (LEO) environment for 5.8 years on Long Duration Exposure Facility (LDEF) has revealed several probable sources for microparticles at this altitude, including natural micrometeorites and manmade debris ranging from paint pigments to bits of stainless steel. A myriad of contamination interferences were identified and their effects on impactor debris identification mitigated during the course of this study. These interferences included pre-, post-, and in-flight deposited particulate surface contaminants, as well as indigenous heterogeneous material contaminants. Non-flight contaminants traced to human origins, including spittle and skin oils, contributed significant levels of alkali-rich carbonaceous interferences. A ubiquitous layer of in-flight deposited silicaceous contamination varied in thickness with location on LDEF and proximity to active electrical fields. In-flight deposited (low velocity) contaminants included urine droplets and bits of metal film from eroded thermal blankets.

A beacon interval shifting scheme for interference mitigation in body area networks.

PubMed

Kim, Seungku; Kim, Seokhwan; Kim, Jin-Woo; Eom, Doo-Seop

2012-01-01

This paper investigates the issue of interference avoidance in body area networks (BANs). IEEE 802.15 Task Group 6 presented several schemes to reduce such interference, but these schemes are still not proper solutions for BANs. We present a novel distributed TDMA-based beacon interval shifting scheme that reduces interference in the BANs. A design goal of the scheme is to avoid the wakeup period of each BAN coinciding with other networks by employing carrier sensing before a beacon transmission. We analyze the beacon interval shifting scheme and investigate the proper back-off length when the channel is busy. We compare the performance of the proposed scheme with the schemes presented in IEEE 802.15 Task Group 6 using an OMNeT++ simulation. The simulation results show that the proposed scheme has a lower packet loss, energy consumption, and delivery-latency than the schemes of IEEE 802.15 Task Group 6.

A Beacon Interval Shifting Scheme for Interference Mitigation in Body Area Networks

PubMed Central

Kim, Seungku; Kim, Seokhwan; Kim, Jin-Woo; Eom, Doo-Seop

2012-01-01

This paper investigates the issue of interference avoidance in body area networks (BANs). IEEE 802.15 Task Group 6 presented several schemes to reduce such interference, but these schemes are still not proper solutions for BANs. We present a novel distributed TDMA-based beacon interval shifting scheme that reduces interference in the BANs. A design goal of the scheme is to avoid the wakeup period of each BAN coinciding with other networks by employing carrier sensing before a beacon transmission. We analyze the beacon interval shifting scheme and investigate the proper back-off length when the channel is busy. We compare the performance of the proposed scheme with the schemes presented in IEEE 802.15 Task Group 6 using an OMNeT++ simulation. The simulation results show that the proposed scheme has a lower packet loss, energy consumption, and delivery-latency than the schemes of IEEE 802.15 Task Group 6. PMID:23112639

Inter-model analysis of tsunami-induced coastal currents

NASA Astrophysics Data System (ADS)

Lynett, Patrick J.; Gately, Kara; Wilson, Rick; Montoya, Luis; Arcas, Diego; Aytore, Betul; Bai, Yefei; Bricker, Jeremy D.; Castro, Manuel J.; Cheung, Kwok Fai; David, C. Gabriel; Dogan, Gozde Guney; Escalante, Cipriano; González-Vida, José Manuel; Grilli, Stephan T.; Heitmann, Troy W.; Horrillo, Juan; Kânoğlu, Utku; Kian, Rozita; Kirby, James T.; Li, Wenwen; Macías, Jorge; Nicolsky, Dmitry J.; Ortega, Sergio; Pampell-Manis, Alyssa; Park, Yong Sung; Roeber, Volker; Sharghivand, Naeimeh; Shelby, Michael; Shi, Fengyan; Tehranirad, Babak; Tolkova, Elena; Thio, Hong Kie; Velioğlu, Deniz; Yalçıner, Ahmet Cevdet; Yamazaki, Yoshiki; Zaytsev, Andrey; Zhang, Y. J.

2017-06-01

To help produce accurate and consistent maritime hazard products, the National Tsunami Hazard Mitigation Program organized a benchmarking workshop to evaluate the numerical modeling of tsunami currents. Thirteen teams of international researchers, using a set of tsunami models currently utilized for hazard mitigation studies, presented results for a series of benchmarking problems; these results are summarized in this paper. Comparisons focus on physical situations where the currents are shear and separation driven, and are thus de-coupled from the incident tsunami waveform. In general, we find that models of increasing physical complexity provide better accuracy, and that low-order three-dimensional models are superior to high-order two-dimensional models. Inside separation zones and in areas strongly affected by eddies, the magnitude of both model-data errors and inter-model differences can be the same as the magnitude of the mean flow. Thus, we make arguments for the need of an ensemble modeling approach for areas affected by large-scale turbulent eddies, where deterministic simulation may be misleading. As a result of the analyses presented herein, we expect that tsunami modelers now have a better awareness of their ability to accurately capture the physics of tsunami currents, and therefore a better understanding of how to use these simulation tools for hazard assessment and mitigation efforts.

Mitigation of solvent interference using a short packed column prior to ion mobility spectrometry.

PubMed

Jafari, Mohammad T; Saraji, Mohammad; Mossaddegh, Mehdi

2017-05-15

This paper introduces a novel approach to overcome the solvent interference in corona discharge-ion mobility spectrometry (CD-IMS) based on the time-resolved signals of the solvent and the analyte. To that end, a short Teflon tube was filled with a low amount of squalene or OV-1, which was prepared and located between the injection port and the entrance of the CD-IMS cell. Through this procedure, a sufficient delay (~5s) was obtained between the introduction of the solvent and the analyte into the reaction region of IMS. This resulted in removing the proton by solvent molecules, as well as increasing the effective collision during the analyte ionization, thereby providing an analysis with more sensitivity, accuracy, and precision. To show the column efficiency, ethion and diazinon (organophosphorus pesticides) were selected as the test compounds and their solutions were analyzed by the proposed method. The amount of sorbent, carrier gas flow rate, and the sorbent temperature affecting the sorbent efficiency were optimized by employing the response surface methodology and the central composite design. The proposed method was exhaustively validated in terms of sensitivity, linearity, and repeatability. In particular, the feasibility of direct injection was successfully verified by the satisfactory results, as compared with those achieved without the prior column. The methodology used in this study is very simple and inexpensive, which can overcome the solvent interference when a solution is directly injected into the CD-IMS. Copyright © 2017 Elsevier B.V. All rights reserved.

Coverage Extension and Balancing the Transmitted Power of the Moving Relay Node at LTE-A Cellular Network

PubMed Central

Aldhaibani, Jaafar A.; Yahya, Abid; Ahmad, R. Badlishah

2014-01-01

The poor capacity at cell boundaries is not enough to meet the growing demand and stringent design which required high capacity and throughput irrespective of user's location in the cellular network. In this paper, we propose new schemes for an optimum fixed relay node (RN) placement in LTE-A cellular network to enhance throughput and coverage extension at cell edge region. The proposed approach mitigates interferences between all nodes and ensures optimum utilization with the optimization of transmitted power. Moreover, we proposed a new algorithm to balance the transmitted power of moving relay node (MR) over cell size and providing required SNR and throughput at the users inside vehicle along with reducing the transmitted power consumption by MR. The numerical analysis along with the simulation results indicates that an improvement in capacity for users is 40% increment at downlink transmission from cell capacity. Furthermore, the results revealed that there is saving nearly 75% from transmitted power in MR after using proposed balancing algorithm. ATDI simulator was used to verify the numerical results, which deals with real digital cartographic and standard formats for terrain. PMID:24672378

Coverage extension and balancing the transmitted power of the moving relay node at LTE-A cellular network.

PubMed

Aldhaibani, Jaafar A; Yahya, Abid; Ahmad, R Badlishah

2014-01-01

The poor capacity at cell boundaries is not enough to meet the growing demand and stringent design which required high capacity and throughput irrespective of user's location in the cellular network. In this paper, we propose new schemes for an optimum fixed relay node (RN) placement in LTE-A cellular network to enhance throughput and coverage extension at cell edge region. The proposed approach mitigates interferences between all nodes and ensures optimum utilization with the optimization of transmitted power. Moreover, we proposed a new algorithm to balance the transmitted power of moving relay node (MR) over cell size and providing required SNR and throughput at the users inside vehicle along with reducing the transmitted power consumption by MR. The numerical analysis along with the simulation results indicates that an improvement in capacity for users is 40% increment at downlink transmission from cell capacity. Furthermore, the results revealed that there is saving nearly 75% from transmitted power in MR after using proposed balancing algorithm. ATDI simulator was used to verify the numerical results, which deals with real digital cartographic and standard formats for terrain.

22 CFR 1006.860 - What factors may influence the debarring official's decision?

Code of Federal Regulations, 2010 CFR

2010-04-01

... not necessarily determinative of your present responsibility. In making a debarment decision, the... official's decision? 1006.860 Section 1006.860 Foreign Relations INTER-AMERICAN FOUNDATION GOVERNMENTWIDE... official's decision? This section lists the mitigating and aggravating factors that the debarring official...

Combinatorial resveratrol and quercetin polymeric micelles mitigate doxorubicin induced cardiotoxicity in vitro and in vivo.

PubMed

Cote, Brianna; Carlson, Lisa Janssen; Rao, Deepa A; Alani, Adam W G

2015-09-10

Doxorubicin hydrochloride (ADR) is an anthracycline antibiotic used to treat various cancers. However, due to its extensive cardiotoxic side effects a lifetime cumulative dose limit of 450-550 mg/m2 exists. The postulated mechanism of the cardiotoxicity is generation of reactive oxygen and nitrogen species. Natural products like resveratrol (RES), and quercetin (QUE) are known free radical scavengers and have shown cardioprotective effects. However, concurrent dosing of these natural products with ADR is limited due to their low solubility, and low oral bioavailability. We hypothesize that the combination of RES and QUE in Pluronic® F127 micelles (mRQ) when co-administered with ADR, will be cardioprotective in vitro and in vivo, while maintaining or increasing the efficacy of ADR against cancer cell lines in vitro. We prepared mRQ micelles capable of retaining 1.1mg/mL and 1.42 mg/mL of RES and QUE respectively. The in vitro release of RES and QUE from the micelles followed first order kinetics over 48h. In vitro cell viability and combination index analysis studies in human ovarian cancer cells (SKOV-3) and rat cardiomyocytes (H9C2) showed that RES:QUE: ADR at 10:10:1 ratio was synergistic in SKOV-3 cells and antagonistic in H9C2 cells. Caspase 3/7 activity studies indicated that mRQ did not interfere with ADR caspase activity in SKOV-3 cells but significantly decreased it in H9C2 cells. The generation of reactive oxygen species (ROS) in SKOV-3 and H9C2 cells in the presence of mRQ also indicated no changes in ROS activity in SKOV-3 cells but significant scavenging in H9C2 cells. Healthy mice were exposed to acute doses of ADR and ADR with mRQ. Based on biochemical estimations the presence of mRQ with ADR conferred full cardioprotection in these mice. Concurrent administration of mRQ with ADR at 10:10:1 ratio provides a viable strategy to mitigate acute ADR induced cardiotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

77 FR 7041 - Changes to Implement Inter Partes Review Proceedings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-10

... comments with the public is more easily accomplished. Electronic comments are preferred to be submitted in... public inspection at the Board of Patent Appeals and Interferences, currently located in Madison East..., on, or after the effective date. DATES: The Office solicits comments from the public on this proposed...

Wideband Channel Modeling in Real Atmospheric Environments with Experimental Evaluation

DTIC Science & Technology

2013-04-01

5] D. F. Gingras and P. Gerstoft. 1997. “The Effect of Propagation on Wideband DS - CDMA Systems in the Suburban Environment,” The First IEEE...are commonly used in spread spectrum communication systems such as Code Division Multiple Access ( CDMA ) systems. Narrowband interference mitigation

On Dangerous Anthropogenic Interference and Climate Change Risk (Invited)

NASA Astrophysics Data System (ADS)

Mann, M. E.

2009-12-01

The United Nations Framework Convention on Climate Change (UNFCCC) commits signatory nations (which includes all major nations including the United States) to stabilizing greenhouse gas concentrations at levels short of Dangerous Anthropogenic Interference (“ DAI”) with the climate. To properly define DAI, one must take into account issues that are not only scientific, but, economic, political, and ethical in nature. Defining DAI is furthermore complicated by the inter-generational and regionally-disaggregated nature of the risks associated with climate change. In this talk, I will explore the nature of anthropogenic climate change risks and the notion of DAI.

Conduction properties of thin films from a water soluble carbon nanotube/hemicellulose complex

NASA Astrophysics Data System (ADS)

Shao, Dongkai; Yotprayoonsak, Peerapong; Saunajoki, Ville; Ahlskog, Markus; Virtanen, Jorma; Kangas, Veijo; Volodin, Alexander; Van Haesendonck, Chris; Burdanova, Maria; Mosley, Connor D. W.; Lloyd-Hughes, James

2018-04-01

We have examined the conductive properties of carbon nanotube based thin films, which were prepared via dispersion in water by non-covalent functionalization of the nanotubes with xylan, a type of hemicellulose. Measurements of low temperature conductivity, Kelvin probe force microscopy, and high frequency (THz) conductivity elucidated the intra-tube and inter-tube charge transport processes in this material. The measurements show excellent conductive properties of the as prepared thin films, with bulk conductivity up to 2000 S cm-1. The transport results demonstrate that the hemicellulose does not seriously interfere with the inter-tube conductance.

Nanoscale molecular communication networks: a game-theoretic perspective

NASA Astrophysics Data System (ADS)

Jiang, Chunxiao; Chen, Yan; Ray Liu, K. J.

2015-12-01

Currently, communication between nanomachines is an important topic for the development of novel devices. To implement a nanocommunication system, diffusion-based molecular communication is considered as a promising bio-inspired approach. Various technical issues about molecular communications, including channel capacity, noise and interference, and modulation and coding, have been studied in the literature, while the resource allocation problem among multiple nanomachines has not been well investigated, which is a very important issue since all the nanomachines share the same propagation medium. Considering the limited computation capability of nanomachines and the expensive information exchange cost among them, in this paper, we propose a game-theoretic framework for distributed resource allocation in nanoscale molecular communication systems. We first analyze the inter-symbol and inter-user interference, as well as bit error rate performance, in the molecular communication system. Based on the interference analysis, we formulate the resource allocation problem as a non-cooperative molecule emission control game, where the Nash equilibrium is found and proved to be unique. In order to improve the system efficiency while guaranteeing fairness, we further model the resource allocation problem using a cooperative game based on the Nash bargaining solution, which is proved to be proportionally fair. Simulation results show that the Nash bargaining solution can effectively ensure fairness among multiple nanomachines while achieving comparable social welfare performance with the centralized scheme.

Unraveling Cell Processes: Interference Imaging Interwoven with Data Analysis

PubMed Central

Brazhe, A. R.; Pavlov, A. N.; Erokhova, L. A.; Yusipovich, A. I.; Maksimov, G. V.; Mosekilde, E.; Sosnovtseva, O. V.

2006-01-01

The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution of hemoglobin, and that interference imaging of neurons can show intracellular compartmentalization and submembrane structures. We investigate temporal and spatial variations of the refractive index for different cell types: isolated neurons, mast cells and erythrocytes. We show that the refractive dynamical properties differ from cell type to cell type and depend on the cellular compartment. Our results suggest that low frequency variations (0.1–0.6 Hz) result from plasma membrane processes and that higher frequency variations (20–26 Hz) are related to the movement of vesicles. Using double-wavelet analysis, we study the modulation of the 1 Hz rhythm in neurons and reveal its changes under depolarization and hyperpolarization of the plasma membrane. We conclude that interference microscopy combined with wavelet analysis is a useful technique for non-invasive cell studies, cell visualization, and investigation of plasma membrane properties. PMID:19669463

Intra-operative navigation of a 3-dimensional needle localization system for precision of irreversible electroporation needles in locally advanced pancreatic cancer.

PubMed

Bond, L; Schulz, B; VanMeter, T; Martin, R C G

2017-02-01

Irreversible electroporation (IRE) uses multiple needles and a series of electrical pulses to create pores in cell membranes and cause cell apoptosis. One of the demands of IRE is the precise needle spacing required. Two-dimensional intraoperative ultrasound (2-D iUS) is currently used to measure inter-needle distances but requires significant expertise. This study evaluates the potential of three-dimensional (3-D) image guidance for placing IRE needles and calculating needle spacing. A prospective clinical evaluation of a 3-D needle localization system (Explorer™) was evaluated in consecutive patients from April 2012 through June 2013 for unresectable pancreatic adenocarcinoma. 3-D reconstructions of patients' anatomy were generated from preoperative CT images, which were aligned to the intraoperative space. Thirty consecutive patients with locally advanced pancreatic cancer were treated with IRE. The needle localization system setup added an average of 6.5 min to each procedure. The 3-D needle localization system increased surgeon confidence and ultimately reduced needle placement time. IRE treatment efficacy is highly dependent on accurate needle spacing. The needle localization system evaluated in this study aims to mitigate these issues by providing the surgeon with additional visualization and data in 3-D. The Explorer™ system provides valuable guidance information and inter-needle distance calculations. Copyright © 2016 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

RACOON: a multiuser QoS design for mobile wireless body area networks.

PubMed

Cheng, Shihheng; Huang, Chingyao; Tu, Chun Chen

2011-10-01

In this study, Random Contention-based Resource Allocation (RACOON) medium access control (MAC) protocol is proposed to support the quality of service (QoS) for multi-user mobile wireless body area networks (WBANs). Different from existing QoS designs that focus on a single WBAN, a multiuser WBAN QoS should further consider both inter-WBAN interference and inter-WBAN priorities. Similar problems have been studied in both overlapped wireless local area networks (WLANs) and Bluetooth piconets that need QoS supports. However, these solutions are designed for non-medical transmissions that do not consider any priority scheme for medical applications. Most importantly, these studies focus on only static or low mobility networks. Network mobility of WBANs will introduce unnecessary inter-network collisions and energy waste, which are not considered by these solutions. The proposed multiuser-QoS protocol, RACOON, simultaneously satisfies the inter WBAN QoS requirements and overcomes the performance degradation caused by WBAN mobility. Simulation results verify that RACOON provides better latency and energy control, as compared with WBAN QoS protocols without considering the inter-WBAN requirements.

Performance Analysis of a Hardware Implemented Complex Signal Kurtosis Radio-Frequency Interference Detector

NASA Technical Reports Server (NTRS)

Schoenwald, Adam J.; Bradley, Damon C.; Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Wong, Mark

2016-01-01

In the field of microwave radiometry, Radio Frequency Interference (RFI) consistently degrades the value of scientific results. Through the use of digital receivers and signal processing, the effects of RFI on scientific measurements can be reduced depending on certain circumstances. As technology allows us to implement wider band digital receivers for radiometry, the problem of RFI mitigation changes. Our work focuses on finding a detector that outperforms real kurtosis in wide band scenarios. The algorithm implemented is a complex signal kurtosis detector which was modeled and simulated. The performance of both complex and real signal kurtosis is evaluated for continuous wave, pulsed continuous wave, and wide band quadrature phase shift keying (QPSK) modulations. The use of complex signal kurtosis increased the detectability of interference.

76 FR 32974 - Sunshine Act Meeting; Open Commission Meeting; Thursday, June 9, 2011

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-07

... a Second Report and Order adopting technical rules to mitigate space path interference between the 17/24 GHz Broadcasting- Satellite Service (BSS) space stations and current and future Direct Broadcasting Service (DBS) space stations that operate in the same frequency band. Reforms to certain of the...

The SPS interference problem-electronic system effects and mitigation techniques

NASA Technical Reports Server (NTRS)

Juroshek, J. R.

1980-01-01

The potential for interference between solar power satellites (SPS) and other Earth satellite operations was examined along with interference problems involving specific electronic devices. Conclusions indicate that interference is likely in the 2500 MHz to 2690 MHz direct broadcast satellite band adjacent to SPS. Estimates of the adjacent channel noise from SPS in this band are as high as -124 dBc/4 kHz and -100 dBc/MHz, where dBc represents decibels relative to the total power in the fundamental. A second potential problem is the 7350 MHz, 3d harmonic from SPS that falls within the 7300 MHz to 7450 MHz space to Earth, government, satellite assignment. Catastrophic failures can be produced in integrated circuits when the microwave power levels coupled into inputs and power leads reach 1 to 100 watts. The failures are typically due to bonding wire melting, metallization failures, and junction shorting. Nondestructive interaction or interference, however, generally occurs with coupled power levels of the order of 10 milliwatts. This integration is due to the rectification of microwave energy by the numerous pn junctions within these circuits.

Abstract ID: 176 Geant4 implementation of inter-atomic interference effect in small-angle coherent X-ray scattering for materials of medical interest.

PubMed

Paternò, Gianfranco; Cardarelli, Paolo; Contillo, Adriano; Gambaccini, Mauro; Taibi, Angelo

2018-01-01

Advanced applications of digital mammography such as dual-energy and tomosynthesis require multiple exposures and thus deliver higher dose compared to standard mammograms. A straightforward manner to reduce patient dose without affecting image quality would be removal of the anti-scatter grid, provided that the involved reconstruction algorithms are able to take the scatter figure into account [1]. Monte Carlo simulations are very well suited for the calculation of X-ray scatter distribution and can be used to integrate such information within the reconstruction software. Geant4 is an open source C++ particle tracking code widely used in several physical fields, including medical physics [2,3]. However, the coherent scattering cross section used by the standard Geant4 code does not take into account the influence of molecular interference. According to the independent atomic scattering approximation (the so-called free-atom model), coherent radiation is indistinguishable from primary radiation because its angular distribution is peaked in the forward direction. Since interference effects occur between x-rays scattered by neighbouring atoms in matter, it was shown experimentally that the scatter distribution is affected by the molecular structure of the target, even in amorphous materials. The most important consequence is that the coherent scatter distribution is not peaked in the forward direction, and the position of the maximum is strongly material-dependent [4]. In this contribution, we present the implementation of a method to take into account inter-atomic interference in small-angle coherent scattering in Geant4, including a dedicated data set of suitable molecular form factor values for several materials of clinical interest. Furthermore, we present scatter images of simple geometric phantoms in which the Rayleigh contribution is rigorously evaluated. Copyright © 2017.

Sharing the Earth, Kit II.

ERIC Educational Resources Information Center

1971

Introducing the pupil to the science of ecology is the purpose of Scholastic's Earth Corps Ecology/Conservation Study Kits for grades 3-6. Simple terms are used to show how all living things are inter-related to their environment, to demonstrate the intricate and delicate balance of nature, and to point out how man's interference with nature's…

47 CFR 90.242 - Travelers' information stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the modulation limiter and the modulated stage. At audio frequencies between 3 kHz and 20 kHz this...' information stations. (a) The frequencies 530 through 1700 kHz in 10 kHz increments may be assigned to the... consideration of possible cross-modulation and inter-modulation interference effects which may result from the...

Surface Mediated Protein Disaggregation

NASA Astrophysics Data System (ADS)

Radhakrishna, Mithun; Kumar, Sanat K.

2014-03-01

Preventing protein aggregation is of both biological and industrial importance. Biologically these aggregates are known to cause amyloid type diseases like Alzheimer's and Parkinson's disease. Protein aggregation leads to reduced activity of the enzymes in industrial applications. Inter-protein interactions between the hydrophobic residues of the protein are known to be the major driving force for protein aggregation. In the current paper we show how surface chemistry and curvature can be tuned to mitigate these inter-protein interactions. Our results calculated in the framework of the Hydrophobic-Polar (HP) lattice model show that, inter-protein interactions can be drastically reduced by increasing the surface hydrophobicity to a critical value corresponding to the adsorption transition of the protein. At this value of surface hydrophobicity, proteins lose inter-protein contacts to gain surface contacts and thus the surface helps in reducing the inter-protein interactions. Further, we show that the adsorption of the proteins inside hydrophobic pores of optimal sizes are most efficient both in reducing inter-protein contacts and simultaneously retaining most of the native-contacts due to strong protein-surface interactions coupled with stabilization due to the confinement. Department of Energy (Grant No DE-FG02-11ER46811).

Nyquist WDM superchannel using offset-16QAM and receiver-side digital spectral shaping.

PubMed

Xiang, Meng; Fu, Songnian; Tang, Ming; Tang, Haoyuan; Shum, Perry; Liu, Deming

2014-07-14

The performance of Nyquist WDM superchannel using advanced modulation formats with coherent detection is degraded due to the existence of both inter-symbol interference (ISI) and inter-channel interference (ICI). Here, we propose and numerically investigate a Nyquist WDM superchannel using offset-16QAM and receiver-side digital spectral shaping (RS-DSS), achieving a spectral efficiency up to 7.44 bit/s/Hz with 7% hard-decision forward error correction (HD-FEC) overhead. Compared with Nyquist WDM superchannel using 16QAM and RS-DSS, the proposed system has 1.4 dB improvement of required OSNR at BER = 10(-3) in the case of back-to-back (B2B) transmission. Furthermore, the range of launched optical power allowed beyond HD-FEC threshold is drastically increased from -6 dBm to 1.2 dBm, after 960 km SSMF transmission with EDFA-only. In particular, no more than 1.8 dB required OSNR penalty at BER = 10(-3) is achieved for the proposed system even with the phase difference between channels varying from 0 to 360 degree.

Hierarchical Equation of Motion Investigation of Decoherence and Relaxation Dynamics in Nonequilibrium Transport through Interacting Quantum Dots

NASA Astrophysics Data System (ADS)

Hartle, Rainer; Cohen, Guy; Reichman, David R.; Millis, Andrew J.

2014-03-01

A recently developed hierarchical quantum master equation approach is used to investigate nonequilibrium electron transport through an interacting double quantum dot system in the regime where the inter-dot coupling is weaker than the coupling to the electrodes. The corresponding eigenstates provide tunneling paths that may interfere constructively or destructively, depending on the energy of the tunneling electrons. Electron-electron interactions are shown to quench these interference effects in bias-voltage dependent ways, leading, in particular, to negative differential resistance, population inversion and an enhanced broadening of resonances in the respective transport characteristics. Relaxation times are found to be very long, and to be correlated with very slow dynamics of the inter-dot coherences (off diagonal density matrix elements). The ability of the hierarchical quantum master equation approach to access very long time scales is crucial for the study of this physics. This work is supported by the National Science Foundation (NSF DMR-1006282 and NSF CHE-1213247), the Yad Hanadiv-Rothschild Foundation (via a Rothschild Fellowship for GC) and the Alexander von Humboldt Foundation (via a Feodor Lynen fellowship for RH).

Design of 2*6 optical hybrid in inter-satellite coherent laser communications

NASA Astrophysics Data System (ADS)

Xu, Nan; Liu, Liren; Liu, De'an; Wan, Lingyu; Zhou, Yu

2008-08-01

Compared with direct detection, homodyne binary phase shift keying receivers can achieve the best sensitivity theoretically, and became the trend of the research and application in inter-satellite coherent laser communications. In coherent optical communication systems an optical hybrid is an essential component of the receiver. It demodulates the incoming signal by mixing it with the local oscillator. We present a design of a 2*6 optical hybrid. 4 output ports of the hybrid give the narrow mixed beams of the incoming signal and the local oscillator shifted by 90°for communication, and the others give the wide mixed beams with a shifted degree of 180°for position errors detection. CCD captures the interference pattern from the wide beams, and then the pattern is processed and analyzed by the computer. Target position information is obtained from characteristic parameter of the interference pattern. The position errors as the control signals of PAT (pointing, acquisition and tracking) subsystem drive the receiver telescope to keep tracking to the target. The application extends to coherent laser rang finder.

Static magnetic Faraday rotation spectroscopy combined with a differential scheme for OH detection

NASA Astrophysics Data System (ADS)

Zhao, Weixiong; Deng, Lunhua; Qian, Xiaodong; Fang, Bo; Gai, Yanbo; Chen, Weidong; Gao, Xiaoming; Zhang, Weijun

2015-04-01

The hydroxyl (OH) radical plays a critical role in atmospheric chemistry due to its high reactivity with volatile organic compounds (VOCs) and other trace gaseous species. Because of its very short life time and very low concentration in the atmosphere, interference-free high sensitivity in-situ OH monitoring by laser spectroscopy represents a real challenge. Faraday rotation spectroscopy (FRS) relies on the particular magneto-optic effect observed for paramagnetic species, which makes it capable of enhancing the detection sensitivity and mitigation of spectral interferences from diamagnetic species in the atmosphere. When an AC magnetic field is used, the Zeeman splitting of the molecular absorption line (and thus the magnetic circular birefringence) is modulated. This provides an 'internal modulation' of the sample, which permits to suppress the external noise like interference fringes. An alternative FRS detection scheme is to use a static magnetic field (DC-field) associated with laser wavelength modulation to effectively modulate the Zeeman splitting of the absorption lines. In the DC field case, wavelength modulation of the laser frequency can provide excellent performance compared to most of the sensing systems based on direct absorption and wavelength modulation spectroscopy. The dimension of the DC solenoid is not limited by the resonant frequency of the RLC circuit, which makes large dimension solenoid coil achievable and the absorption base length could be further increased. By employing a combination of the environmental photochemical reactor or smog chamber with multipass absorption cell, one can lower the minimum detection limit for high accuracy atmospheric chemistry studies. In this paper, we report on the development of a DC field based FRS in conjunction with a balanced detection scheme for OH radical detection at 2.8 μm and the construction of OH chemistry research platform which combined a large dimension superconducting magnetic coil with the multipass cell and photochemical reactor chamber for real time in-situ measurement of OH radical concentration in the chamber.

Evaluation of electrosurgical interference to low-power spread-spectrum local area net transceivers.

PubMed

Gibby, G L; Schwab, W K; Miller, W C

1997-11-01

To study whether an electrosurgery device interferes with the operation of a low-power spread-spectrum wireless network adapter. Nonrandomized, unblinded trials with controls, conducted in the corridor of our institution's operating suite using two portable computers equipped with RoamAbout omnidirectional 250 mW spread-spectrum 928 MHz wireless network adapters. To simulate high power electrosurgery interference, a 100-watt continuous electrocoagulation arc was maintained five feet from the receiving adapter, while device reported signal to noise values were measured at 150 feet and 400 feet distance between the wireless-networked computers. At 150 feet range, and with continuous 100-watt electrocoagulation arc five feet from one computer, error-corrected local area net throughput was measured by sending and receiving a large file multiple times. The reported signal to noise (N = 50) decreased with electrocoagulation from 36.42+/-3.47 (control) to 31.85+/-3.64 (electrocoagulation) (p < 0.001) at 400 feet inter-adapter distance, and from 64.53+/-1.43 (control) to 60.12+/-3.77 (electrocoagulation) (p < 0.001) at 150 feet inter-adapter distance. There was no statistically significant change in network throughput (average 93 kbyte/second) at 150 feet inter-adapter distance, either transmitting or receiving during continuous 100 Watt electrocoagulation arc. The manufacturer indicates "acceptable" performance will be obtained with signal to noise values as low as 20. In view of this, while electrocoagulation affects this spread spectrum network adapter, the effects are small even at 400 feet. At a distance of 150 feet, no discernible effect on network communications was found, suggesting that if other obstructions are minimal, within a wide range on one floor of an operating suite, network communications may be maintained using the technology of this wireless spread spectrum network adapter. The impact of such adapters on cardiac pacemakers should be studied. Wireless spread spectrum network adapters are an attractive technology for mobile computer communications in the operating room.

Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things.

PubMed

Wang, Lusheng; Wang, Yamei; Ding, Zhizhong; Wang, Xiumin

2015-09-18

With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified.

Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things

PubMed Central

Wang, Lusheng; Wang, Yamei; Ding, Zhizhong; Wang, Xiumin

2015-01-01

With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified. PMID:26393617

A new topology of fuel cell hybrid power source for efficient operation and high reliability

NASA Astrophysics Data System (ADS)

Bizon, Nicu

2011-03-01

This paper analyzes a new fuel cell Hybrid Power Source (HPS) topology having the feature to mitigate the current ripple of the fuel cell inverter system. In the operation of the inverter system that is grid connected or supplies AC motors in vehicle application, the current ripple normally appears at the DC port of the fuel cell HPS. Consequently, if mitigation measures are not applied, this ripple is back propagated to the fuel cell stack. Other features of the proposed fuel cell HPS are the Maximum Power Point (MPP) tracking, high reliability in operation under sharp power pulses and improved energy efficiency in high power applications. This topology uses an inverter system directly powered from the appropriate fuel cell stack and a controlled buck current source as low power source used for ripple mitigation. The low frequency ripple mitigation is based on active control. The anti-ripple current is injected in HPS output node and this has the LF power spectrum almost the same with the inverter ripple. Consequently, the fuel cell current ripple is mitigated by the designed active control. The ripple mitigation performances are evaluated by indicators that are defined to measure the mitigation ratio of the low frequency harmonics. In this paper it is shown that good performances are obtained by using the hysteretic current control, but better if a dedicated nonlinear controller is used. Two ways to design the nonlinear control law are proposed. First is based on simulation trials that help to draw the characteristic of ripple mitigation ratio vs. fuel cell current ripple. The second is based on Fuzzy Logic Controller (FLC). The ripple factor is up to 1% in both cases.

Power budget of direct-detection ultra-dense WDM-Nyquist-SCM PON with low-complexity SSBI mitigation

NASA Astrophysics Data System (ADS)

Soeiro, Ricardo O. J.; Alves, Tiago M. F.; Cartaxo, Adolfo V. T.

2017-07-01

The power budget (PB) of a direct-detection ultra-dense wavelength division/subcarrier multiplexing (SCM) passive optical network (PON) is assessed numerically for downstream, when a low-complexity iterative signal-to-signal beat interference (SSBI) mitigation technique is employed. Each SCM signal, inserted in a 12.5 GHz width optical channel, is comprised of two or three electrically generated and multiplexed 16-quadrature-amplitude-modulation (QAM) or 32-QAM Nyquist pulse-shaped subcarriers, each with a 7% forward error correction bit rate of 10.7 Gbit/s. The PB and maximum number of optical network units (ONUs) served by each optical line terminal (OLT) are compared with and without SSBI mitigation. When SSBI mitigation is realized, PB gains up to 4.5 dB are attained relative to the PB in the absence of SSBI mitigation. The PB gain enabled by the SSBI mitigation technique proposed in this work increases the number of ONUs served per OLT at least by a factor of 2, for the cases of higher spectral efficiency. In particular, for a SCM signal comprised of three subcarriers, the maximum number of ONUs served per OLT is between 2 and 32, and between 8 and 64, in the absence of SSBI mitigation, and when SSBI mitigation is employed, respectively, depending on the fiber length (up to 50 km) and order of QAM.

Shared Socio-Economic Pathways of the Energy Sector – Quantifying the Narratives

DOE PAGES

Bauer, Nico; Calvin, Katherine; Emmerling, Johannes; ...

2016-08-23

Energy is crucial for supporting basic human needs, development and well-being. The future evolution of the scale and character of the energy system will be fundamentally shaped by socioeconomic conditions and drivers, available energy resources, technologies of energy supply and transformation, and end-use energy demand. However, because energy-related activities are significant sources of greenhouse gas (GHG) emissions and other environmental and social externalities, energy system development will also be influenced by social acceptance and strategic policy choices. All of these uncertainties have important implications for many aspects of economic and environmental sustainability, and climate change in particular. In the Shared-Socioeconomicmore » Pathway (SSP) framework these uncertainties are structured into five narratives, arranged according to the challenges to climate change mitigation and adaptation. In this study we explore future energy sector developments across the five SSPs using Integrated Assessment Models (IAMs), and we also provide summary output and analysis for selected scenarios of global emissions mitigation policies. The mitigation challenge strongly corresponds with global baseline energy sector growth over the 21st century, which varies between 40% and 230% depending on final energy consumer behavior, technological improvements, resource availability and policies. The future baseline CO 2-emission range is even larger, as the most energy-intensive SSP also incorporates a comparatively high share of carbon-intensive fossil fuels, and vice versa. Inter-regional disparities in the SSPs are consistent with the underlying socioeconomic assumptions; these differences are particularly strong in the SSPs with large adaptation challenges, which have little inter-regional convergence in long-term income and final energy demand levels. The scenarios presented do not include feedbacks of climate change on energy sector development. The energy sector SSPs with and without emissions mitigation policies are introduced and analyzed here in order to contribute to future research in climate sciences, mitigation analysis, and studies on impacts, adaptation and vulnerability.« less

School Public Relations: Helping an American Institution Pass Its Most Crucial Test

ERIC Educational Resources Information Center

Boyd, Ellen

2004-01-01

The professional discipline of strategic public relations offers many benefits to organizations. It helps them prevent and mitigate crises. It allows them to identify and manage issues that may interfere with their goals and objectives. It also leads them in building and maintaining quality relationships with strategic publics. However, can the…

Towards Mitigating Heterogeneous Wireless Interference in Spectrum Bands with Unlicensed Access

ERIC Educational Resources Information Center

Nychis, George P.

2013-01-01

In the past two decades, we have seen an unprecedented rise in unlicensed wireless devices and applications of wireless technology. To meet various application constraints, we continually customize the radios and their protocols to the application domain which has led to significant diversity in spectrum use. Unfortunately, this diversity (coupled…

Quantitation of polyamines in cultured cells and tissue homogenates by reversed-phase high-performance liquid chromatography of their benzoyl derivatives.

PubMed

Verkoelen, C F; Romijn, J C; Schroeder, F H; van Schalkwijk, W P; Splinter, T A

1988-04-08

A rapid and simple method, originally described by Redmond and Tseng [J. Chromatogr., 170 (1979) 479] was applied to the analysis of di- and polyamines in cultured human tumour cells and human tumour xenografts. Optimization of the procedures and evaluation of the characteristic features of the assay are described. The (modified) procedure employs precolumn derivatization with benzoyl chloride, extraction of the derivatives by chloroform, separation by reversed-phase high-performance liquid chromatography under isocratic conditions and detection by ultraviolet absorbance measurement at 229 nm. The complete analysis was accomplished within 10 min per sample. The detection limit was ca. 1 pmol. The intra- and inter-assay coefficients of variation were 2.5-4.4% and 3.4-13.1%, respectively. The presence of well known inhibitors of polyamine biosynthesis, such as DL-alpha-difluoromethylornithine and methylglyoxal bis(guanylhydrazone), did not interfere with the assay, and disturbance by cyclohexylamine could be avoided by changing the polarity of the mobile phase. The method proved to be very suitable because it is rapid, simple, requires a minimum of sample pretreatment, and still provides sufficient sensitivity to quantitate polyamines in relatively small amounts of cells (10(5) cells) or tumour tissues (less than 1 mg), even after treatment with inhibitors of polyamine biosynthesis.

Soft-Decision-Data Reshuffle to Mitigate Pulsed Radio Frequency Interference Impact on Low-Density-Parity-Check Code Performance

NASA Technical Reports Server (NTRS)

Ni, Jianjun David

2011-01-01

This presentation briefly discusses a research effort on mitigation techniques of pulsed radio frequency interference (RFI) on a Low-Density-Parity-Check (LDPC) code. This problem is of considerable interest in the context of providing reliable communications to the space vehicle which might suffer severe degradation due to pulsed RFI sources such as large radars. The LDPC code is one of modern forward-error-correction (FEC) codes which have the decoding performance to approach the Shannon Limit. The LDPC code studied here is the AR4JA (2048, 1024) code recommended by the Consultative Committee for Space Data Systems (CCSDS) and it has been chosen for some spacecraft design. Even though this code is designed as a powerful FEC code in the additive white Gaussian noise channel, simulation data and test results show that the performance of this LDPC decoder is severely degraded when exposed to the pulsed RFI specified in the spacecraft s transponder specifications. An analysis work (through modeling and simulation) has been conducted to evaluate the impact of the pulsed RFI and a few implemental techniques have been investigated to mitigate the pulsed RFI impact by reshuffling the soft-decision-data available at the input of the LDPC decoder. The simulation results show that the LDPC decoding performance of codeword error rate (CWER) under pulsed RFI can be improved up to four orders of magnitude through a simple soft-decision-data reshuffle scheme. This study reveals that an error floor of LDPC decoding performance appears around CWER=1E-4 when the proposed technique is applied to mitigate the pulsed RFI impact. The mechanism causing this error floor remains unknown, further investigation is necessary.

Performance Analysis of a Hardware Implemented Complex Signal Kurtosis Radio-Frequency Interference Detector

NASA Technical Reports Server (NTRS)

Schoenwald, Adam J.; Bradley, Damon C.; Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Wong, Mark

2016-01-01

Radio-frequency interference (RFI) is a known problem for passive remote sensing as evidenced in the L-band radiometers SMOS, Aquarius and more recently, SMAP. Various algorithms have been developed and implemented on SMAP to improve science measurements. This was achieved by the use of a digital microwave radiometer. RFI mitigation becomes more challenging for microwave radiometers operating at higher frequencies in shared allocations. At higher frequencies larger bandwidths are also desirable for lower measurement noise further adding to processing challenges. This work focuses on finding improved RFI mitigation techniques that will be effective at additional frequencies and at higher bandwidths. To aid the development and testing of applicable detection and mitigation techniques, a wide-band RFI algorithm testing environment has been developed using the Reconfigurable Open Architecture Computing Hardware System (ROACH) built by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) Group. The testing environment also consists of various test equipment used to reproduce typical signals that a radiometer may see including those with and without RFI. The testing environment permits quick evaluations of RFI mitigation algorithms as well as show that they are implementable in hardware. The algorithm implemented is a complex signal kurtosis detector which was modeled and simulated. The complex signal kurtosis detector showed improved performance over the real kurtosis detector under certain conditions. The real kurtosis is implemented on SMAP at 24 MHz bandwidth. The complex signal kurtosis algorithm was then implemented in hardware at 200 MHz bandwidth using the ROACH. In this work, performance of the complex signal kurtosis and the real signal kurtosis are compared. Performance evaluations and comparisons in both simulation as well as experimental hardware implementations were done with the use of receiver operating characteristic (ROC) curves.

Work-family conflict and sleep disturbance: the Malaysian working women study.

PubMed

Aazami, Sanaz; Mozafari, Mosayeb; Shamsuddin, Khadijah; Akmal, Syaqirah

2016-01-01

This study aimed at assessing effect of the four dimensions of work-family conflicts (strain and time-based work interference into family and family interference into work) on sleep disturbance in Malaysian working women. This cross-sectional study was conducted among 325 Malaysian married working women. Multiple-stage simple random sampling method was used to recruit women from public service departments of Malaysia. Self-administrated questionnaires were used to measure the study variables and data were analyzed using SPSS version 21. We found that high level of the four dimensions of work-family conflicts significantly increase sleep disturbance. Our analyses also revealed an age-dependent effect of the work-family conflict on sleep disturbance. Women in their 20 to 30 yr old suffer from sleep disturbance due to high level of time-based and strain-based work-interference into family. However, the quality of sleep among women aged 30-39 were affected by strain-based family-interference into work. Finally, women older than 40 yr had significantly disturbed sleep due to strain-based work-interference into family as well as time-based family interference into work. Our findings showed that sleep quality of working women might be disturbed by experiencing high level of work-family conflict. However, the effects of inter-role conflicts on sleep varied among different age groups.

Design and performance investigation of LDPC-coded upstream transmission systems in IM/DD OFDM-PONs

NASA Astrophysics Data System (ADS)

Gong, Xiaoxue; Guo, Lei; Wu, Jingjing; Ning, Zhaolong

2016-12-01

In Intensity-Modulation Direct-Detection (IM/DD) Orthogonal Frequency Division Multiplexing Passive Optical Networks (OFDM-PONs), aside from Subcarrier-to-Subcarrier Intermixing Interferences (SSII) induced by square-law detection, the same laser frequency for data sending from Optical Network Units (ONUs) results in ONU-to-ONU Beating Interferences (OOBI) at the receiver. To mitigate those interferences, we design a Low-Density Parity Check (LDPC)-coded and spectrum-efficient upstream transmission system. A theoretical channel model is also derived, in order to analyze the detrimental factors influencing system performances. Simulation results demonstrate that the receiver sensitivity is improved 3.4 dB and 2.5 dB under QPSK and 8QAM, respectively, after 100 km Standard Single-Mode Fiber (SSMF) transmission. Furthermore, the spectrum efficiency can be improved by about 50%.

Evaluation of RNAi and CRISPR technologies by large-scale gene expression profiling in the Connectivity Map.

PubMed

Smith, Ian; Greenside, Peyton G; Natoli, Ted; Lahr, David L; Wadden, David; Tirosh, Itay; Narayan, Rajiv; Root, David E; Golub, Todd R; Subramanian, Aravind; Doench, John G

2017-11-01

The application of RNA interference (RNAi) to mammalian cells has provided the means to perform phenotypic screens to determine the functions of genes. Although RNAi has revolutionized loss-of-function genetic experiments, it has been difficult to systematically assess the prevalence and consequences of off-target effects. The Connectivity Map (CMAP) represents an unprecedented resource to study the gene expression consequences of expressing short hairpin RNAs (shRNAs). Analysis of signatures for over 13,000 shRNAs applied in 9 cell lines revealed that microRNA (miRNA)-like off-target effects of RNAi are far stronger and more pervasive than generally appreciated. We show that mitigating off-target effects is feasible in these datasets via computational methodologies to produce a consensus gene signature (CGS). In addition, we compared RNAi technology to clustered regularly interspaced short palindromic repeat (CRISPR)-based knockout by analysis of 373 single guide RNAs (sgRNAs) in 6 cells lines and show that the on-target efficacies are comparable, but CRISPR technology is far less susceptible to systematic off-target effects. These results will help guide the proper use and analysis of loss-of-function reagents for the determination of gene function.

Suppression of AC railway power-line interference in ECG signals recorded by public access defibrillators

PubMed Central

Dotsinsky, Ivan

2005-01-01

Background Public access defibrillators (PADs) are now available for more efficient and rapid treatment of out-of-hospital sudden cardiac arrest. PADs are used normally by untrained people on the streets and in sports centers, airports, and other public areas. Therefore, automated detection of ventricular fibrillation, or its exclusion, is of high importance. A special case exists at railway stations, where electric power-line frequency interference is significant. Many countries, especially in Europe, use 16.7 Hz AC power, which introduces high level frequency-varying interference that may compromise fibrillation detection. Method Moving signal averaging is often used for 50/60 Hz interference suppression if its effect on the ECG spectrum has little importance (no morphological analysis is performed). This approach may be also applied to the railway situation, if the interference frequency is continuously detected so as to synchronize the analog-to-digital conversion (ADC) for introducing variable inter-sample intervals. A better solution consists of rated ADC, software frequency measuring, internal irregular re-sampling according to the interference frequency, and a moving average over a constant sample number, followed by regular back re-sampling. Results The proposed method leads to a total railway interference cancellation, together with suppression of inherent noise, while the peak amplitudes of some sharp complexes are reduced. This reduction has negligible effect on accurate fibrillation detection. Conclusion The method is developed in the MATLAB environment and represents a useful tool for real time railway interference suppression. PMID:16309558

Suppression of AC railway power-line interference in ECG signals recorded by public access defibrillators.

PubMed

Dotsinsky, Ivan

2005-11-26

Public access defibrillators (PADs) are now available for more efficient and rapid treatment of out-of-hospital sudden cardiac arrest. PADs are used normally by untrained people on the streets and in sports centers, airports, and other public areas. Therefore, automated detection of ventricular fibrillation, or its exclusion, is of high importance. A special case exists at railway stations, where electric power-line frequency interference is significant. Many countries, especially in Europe, use 16.7 Hz AC power, which introduces high level frequency-varying interference that may compromise fibrillation detection. Moving signal averaging is often used for 50/60 Hz interference suppression if its effect on the ECG spectrum has little importance (no morphological analysis is performed). This approach may be also applied to the railway situation, if the interference frequency is continuously detected so as to synchronize the analog-to-digital conversion (ADC) for introducing variable inter-sample intervals. A better solution consists of rated ADC, software frequency measuring, internal irregular re-sampling according to the interference frequency, and a moving average over a constant sample number, followed by regular back re-sampling. The proposed method leads to a total railway interference cancellation, together with suppression of inherent noise, while the peak amplitudes of some sharp complexes are reduced. This reduction has negligible effect on accurate fibrillation detection. The method is developed in the MATLAB environment and represents a useful tool for real time railway interference suppression.

Packet loss mitigation for biomedical signals in healthcare telemetry.

PubMed

Garudadri, Harinath; Baheti, Pawan K

2009-01-01

In this work, we propose an effective application layer solution for packet loss mitigation in the context of Body Sensor Networks (BSN) and healthcare telemetry. Packet losses occur due to many reasons including excessive path loss, interference from other wireless systems, handoffs, congestion, system loading, etc. A call for action is in order, as packet losses can have extremely adverse impact on many healthcare applications relying on BAN and WAN technologies. Our approach for packet loss mitigation is based on Compressed Sensing (CS), an emerging signal processing concept, wherein significantly fewer sensor measurements than that suggested by Shannon/Nyquist sampling theorem can be used to recover signals with arbitrarily fine resolution. We present simulation results demonstrating graceful degradation of performance with increasing packet loss rate. We also compare the proposed approach with retransmissions. The CS based packet loss mitigation approach was found to maintain up to 99% beat-detection accuracy at packet loss rates of 20%, with a constant latency of less than 2.5 seconds.

Strategies for assessing inter- and intra-specific variation in tree biomass in the interior west

Treesearch

David L.R. Affleck; John M. Goodburn; John D. Shaw

2012-01-01

Wildfire hazard mitigation and bioenergy harvesting have emerged as forest management priorities throughout the Interior West (IW) of the USA. Regional forest inventory and forecasting applications are therefore increasingly focused on tree biomass, including biomass in traditionally non-merchantable components. Yet accurate biomass equations for the latter components...

Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions

NASA Astrophysics Data System (ADS)

Lo, Wei-Yang; Yang, Yong

2014-08-01

Fuel cladding chemical interaction (FCCI) has been identified as one of the crucial issues for developing Ferritic/Martensitic (F/M) stainless steel claddings for metallic fuels in a fast reactor. The anticipated elevated temperature and high neutron flux can significantly aggravate the FCCI, in terms of formation of inter-diffusion and lower melting point eutectic phases. To mitigate the FCCI, vanadium carbide coating as a diffusion barrier was deposited on the HT-9 substrate using a pack cementation diffusion coating (PCDC) method, and the processing temperature was optimized down to 730 °C. A solid metallurgical bonding between the coating layer and substrate was achieved, and the coating is free from through depth cracks. The microstructural characterizations using SEM and TEM show a nanostructured grain structure. EDS/WDS and XRD analysis confirm the phase of coating layer as V2C. Diffusion couple tests at 660 °C for 100 h demonstrate that V2C layer with a thickness of less than 5 μm can effectively eliminate the inter-diffusion between the lanthanide cerium and HT-9 steel.

Earth Is My Home, Kit I.

ERIC Educational Resources Information Center

1971

Introducing the pupil to the science of ecology is the purpose of Scholastic's Earth Corps Ecology/Conservation Study Kits for grades 3-6. Simple terms are used to show how all living things are inter-related to their environment, to demonstrate the intricate and delicate balance of nature, and to point out how man's interference with nature's…

Transient inter-cellular polymeric linker.

PubMed

Ong, Siew-Min; He, Lijuan; Thuy Linh, Nguyen Thi; Tee, Yee-Han; Arooz, Talha; Tang, Guping; Tan, Choon-Hong; Yu, Hanry

2007-09-01

Three-dimensional (3D) tissue-engineered constructs with bio-mimicry cell-cell and cell-matrix interactions are useful in regenerative medicine. In cell-dense and matrix-poor tissues of the internal organs, cells support one another via cell-cell interactions, supplemented by small amount of the extra-cellular matrices (ECM) secreted by the cells. Here we connect HepG2 cells directly but transiently with inter-cellular polymeric linker to facilitate cell-cell interaction and aggregation. The linker consists of a non-toxic low molecular-weight polyethyleneimine (PEI) backbone conjugated with multiple hydrazide groups that can aggregate cells within 30 min by reacting with the aldehyde handles on the chemically modified cell-surface glycoproteins. The cells in the cellular aggregates proliferated; and maintained the cortical actin distribution of the 3D cell morphology while non-aggregated cells died over 7 days of suspension culture. The aggregates lost distinguishable cell-cell boundaries within 3 days; and the ECM fibers became visible around cells from day 3 onwards while the inter-cellular polymeric linker disappeared from the cell surfaces over time. The transient inter-cellular polymeric linker can be useful for forming 3D cellular and tissue constructs without bulk biomaterials or extensive network of engineered ECM for various applications.

Bacterial cell identification in differential interference contrast microscopy images.

PubMed

Obara, Boguslaw; Roberts, Mark A J; Armitage, Judith P; Grau, Vicente

2013-04-23

Microscopy image segmentation lays the foundation for shape analysis, motion tracking, and classification of biological objects. Despite its importance, automated segmentation remains challenging for several widely used non-fluorescence, interference-based microscopy imaging modalities. For example in differential interference contrast microscopy which plays an important role in modern bacterial cell biology. Therefore, new revolutions in the field require the development of tools, technologies and work-flows to extract and exploit information from interference-based imaging data so as to achieve new fundamental biological insights and understanding. We have developed and evaluated a high-throughput image analysis and processing approach to detect and characterize bacterial cells and chemotaxis proteins. Its performance was evaluated using differential interference contrast and fluorescence microscopy images of Rhodobacter sphaeroides. Results demonstrate that the proposed approach provides a fast and robust method for detection and analysis of spatial relationship between bacterial cells and their chemotaxis proteins.

Cellular telephone interference with medical equipment.

PubMed

Tri, Jeffrey L; Severson, Rodney P; Firl, Allen R; Hayes, David L; Abenstein, John P

2005-10-01

To assess the potential electromagnetic interference (EMI) effects that new or current-generation cellular telephones have on medical devices. For this study, performed at the Mayo Clinic in Rochester, Minn, between March 9, 2004, and April 24, 2004, we tested 16 different medical devices with 6 cellular telephones to assess the potential for EMI. Two of the medical devices were tested with both new and old interface modules. The 6 cellular telephones chosen represent the different cellular technology protocols in use: Code Division Multiple Access (2 models), Global System for Mobile communications, Integrated Digital Enhanced Network, Time Division Multiple Access, and analog. The cellular telephones were tested when operating at or near their maximum power output. The medical devices, connected to clinical simulators during testing, were monitored by observing the device displays and alarms. Of 510 tests performed, the incidence of clinically important interference was 1.2%; EMI was Induced in 108 tests (21.2%). Interference occurred in 7 (44%) of the 16 devices tested. Cellular telephones can interfere with medical equipment. Technology changes in both cellular telephones and medical equipment may continue to mitigate or may worsen clinically relevant interference. Compared with cellular telephones tested in previous studies, those currently in use must be closer to medical devices before any interference is noticed. However, periodic testing of cellular telephones to determine their effects on medical equipment will be required.

Robust X-ray angular correlations for the study of meso-structures

DOE PAGES

Lhermitte, Julien R.; Tian, Cheng; Stein, Aaron; ...

2017-05-08

As self-assembling nanomaterials become more sophisticated, it is becoming increasingly important to measure the structural order of finite-sized assemblies of nano-objects. These mesoscale clusters represent an acute challenge to conventional structural probes, owing to the range of implicated size scales (10 nm to several micrometres), the weak scattering signal and the dynamic nature of meso-clusters in native solution environments. The high X-ray flux and coherence of modern synchrotrons present an opportunity to extract structural information from these challenging systems, but conventional ensemble X-ray scattering averages out crucial information about local particle configurations. Conversely, a single meso-cluster scatters too weakly tomore » recover the full diffraction pattern. Using X-ray angular cross-correlation analysis, it is possible to combine multiple noisy measurements to obtain robust structural information. This paper explores the key theoretical limits and experimental challenges that constrain the application of these methods to probing structural order in real nanomaterials. A metric is presented to quantify the signal-to-noise ratio of angular correlations, and it is used to identify several experimental artifacts that arise. In particular, it is found that background scattering, data masking and inter-cluster interference profoundly affect the quality of correlation analyses. A robust workflow is demonstrated for mitigating these effects and extracting reliable angular correlations from realistic experimental data.« less

Cascaded neural networks for sequenced propagation estimation, multiuser detection, and adaptive radio resource control of third-generation wireless networks for multimedia services

NASA Astrophysics Data System (ADS)

Hortos, William S.

1999-03-01

A hybrid neural network approach is presented to estimate radio propagation characteristics and multiuser interference and to evaluate their combined impact on throughput, latency and information loss in third-generation (3G) wireless networks. The latter three performance parameters influence the quality of service (QoS) for multimedia services under consideration for 3G networks. These networks, based on a hierarchical architecture of overlaying macrocells on top of micro- and picocells, are planned to operate in mobile urban and indoor environments with service demands emanating from circuit-switched, packet-switched and satellite-based traffic sources. Candidate radio interfaces for these networks employ a form of wideband CDMA in 5-MHz and wider-bandwidth channels, with possible asynchronous operation of the mobile subscribers. The proposed neural network (NN) architecture allocates network resources to optimize QoS metrics. Parameters of the radio propagation channel are estimated, followed by control of an adaptive antenna array at the base station to minimize interference, and then joint multiuser detection is performed at the base station receiver. These adaptive processing stages are implemented as a sequence of NN techniques that provide their estimates as inputs to a final- stage Kohonen self-organizing feature map (SOFM). The SOFM optimizes the allocation of available network resources to satisfy QoS requirements for variable-rate voice, data and video services. As the first stage of the sequence, a modified feed-forward multilayer perceptron NN is trained on the pilot signals of the mobile subscribers to estimate the parameters of shadowing, multipath fading and delays on the uplinks. A recurrent NN (RNN) forms the second stage to control base stations' adaptive antenna arrays to minimize intra-cell interference. The third stage is based on a Hopfield NN (HNN), modified to detect multiple users on the uplink radio channels to mitigate multiaccess interference, control carrier-sense multiple-access (CSMA) protocols, and refine call handoff procedures. In the final stage, the Kohonen SOFM, operating in a hybrid continuous and discrete space, adaptively allocates the resources of antenna-based cell sectorization, activity monitoring, variable-rate coding, power control, handoff and caller admission to meet user demands for various multimedia services at minimum QoS levels. The performance of the NN cascade is evaluated through simulation of a candidate 3G wireless network using W-CDMA parameters in a small-cell environment. The simulated network consists of a representative number of cells. Mobile users with typical movement patterns are assumed. QoS requirements for different classes of multimedia services are considered. The proposed method is shown to provide relatively low probability of new call blocking and handoff dropping, while maintaining efficient use of the network's radio resources.

A Multipath Mitigation Algorithm for vehicle with Smart Antenna

NASA Astrophysics Data System (ADS)

Ji, Jing; Zhang, Jiantong; Chen, Wei; Su, Deliang

2018-01-01

In this paper, the antenna array adaptive method is used to eliminate the multipath interference in the environment of GPS L1 frequency. Combined with the power inversion (PI) algorithm and the minimum variance no distortion response (MVDR) algorithm, the anti-Simulation and verification of the antenna array, and the program into the FPGA, the actual test on the CBD road, the theoretical analysis of the LCMV criteria and PI and MVDR algorithm principles and characteristics of MVDR algorithm to verify anti-multipath interference performance is better than PI algorithm, The satellite navigation in the field of vehicle engineering practice has some guidance and reference.

Assessment of the Impacts of Radio Frequency Interference on SMAP Radar and Radiometer Measurements

NASA Technical Reports Server (NTRS)

Chen, Curtis W.; Piepmeier, Jeffrey R.; Johnson, Joel T.; Hirad Ghaemi

2012-01-01

The NASA Soil Moisture Active and Passive (SMAP) mission will measure soil moisture with a combination of Lband radar and radiometer measurements. We present an assessment of the expected impact of radio frequency interference (RFI) on SMAP performance, incorporating projections based on recent data collected by the Aquarius and SMOS missions. We discuss the impacts of RFI on the radar and radiometer separately given the differences in (1) RFI environment between the shared radar band and the protected radiometer band, (2) mitigation techniques available for the different measurements, and (3) existing data sources available that can inform predictions for SMAP.

Getting more from visual working memory: Retro-cues enhance retrieval and protect from visual interference.

PubMed

Souza, Alessandra S; Rerko, Laura; Oberauer, Klaus

2016-06-01

Visual working memory (VWM) has a limited capacity. This limitation can be mitigated by the use of focused attention: if attention is drawn to the relevant working memory content before test, performance improves (the so-called retro-cue benefit). This study tests 2 explanations of the retro-cue benefit: (a) Focused attention protects memory representations from interference by visual input at test, and (b) focusing attention enhances retrieval. Across 6 experiments using color recognition and color reproduction tasks, we varied the amount of color interference at test, and the delay between a retrieval cue (i.e., the retro-cue) and the memory test. Retro-cue benefits were larger when the memory test introduced interfering visual stimuli, showing that the retro-cue effect is in part because of protection from visual interference. However, when visual interference was held constant, retro-cue benefits were still obtained whenever the retro-cue enabled retrieval of an object from VWM but delayed response selection. Our results show that accessible information in VWM might be lost in the processes of testing memory because of visual interference and incomplete retrieval. This is not an inevitable state of affairs, though: Focused attention can be used to get the most out of VWM. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Joint channel estimation and multi-user detection for multipath fading channels in DS-CDMA systems

NASA Astrophysics Data System (ADS)

Wu, Sau-Hsuan; Kuo, C.-C. Jay

2002-11-01

The technique of joint blind channel estimation and multiple access interference (MAI) suppression for an asynchronous code-division multiple-access (CDMA) system is investigated in this research. To identify and track dispersive time-varying fading channels and to avoid the phase ambiguity that come with the second-order statistic approaches, a sliding-window scheme using the expectation maximization (EM) algorithm is proposed. The complexity of joint channel equalization and symbol detection for all users increases exponentially with system loading and the channel memory. The situation is exacerbated if strong inter-symbol interference (ISI) exists. To reduce the complexity and the number of samples required for channel estimation, a blind multiuser detector is developed. Together with multi-stage interference cancellation using soft outputs provided by this detector, our algorithm can track fading channels with no phase ambiguity even when channel gains attenuate close to zero.

The use of religion in death penalty sentencing trials.

PubMed

Miller, Monica K; Bornstein, Brian H

2006-12-01

Both prosecutors and defense attorneys have presented religious appeals and testimony about a defendant's religious activities in order to influence capital jurors' sentencing. Courts that have objected to this use of religion fear that religion will improperly influence jurors' decisions and interfere with their ability to weigh aggravators and mitigators. This study investigated the effects of both prosecution and defense appeals. Prosecution appeals did not affect verdict decisions; however, use of religion by the defense affected both verdicts and the weighing of aggravators and mitigators. These results could be due to differences in perceived sincerity and remorse that are conveyed in the various appeals.

Correction of gene expression data: Performance-dependency on inter-replicate and inter-treatment biases.

PubMed

Darbani, Behrooz; Stewart, C Neal; Noeparvar, Shahin; Borg, Søren

2014-10-20

This report investigates for the first time the potential inter-treatment bias source of cell number for gene expression studies. Cell-number bias can affect gene expression analysis when comparing samples with unequal total cellular RNA content or with different RNA extraction efficiencies. For maximal reliability of analysis, therefore, comparisons should be performed at the cellular level. This could be accomplished using an appropriate correction method that can detect and remove the inter-treatment bias for cell-number. Based on inter-treatment variations of reference genes, we introduce an analytical approach to examine the suitability of correction methods by considering the inter-treatment bias as well as the inter-replicate variance, which allows use of the best correction method with minimum residual bias. Analyses of RNA sequencing and microarray data showed that the efficiencies of correction methods are influenced by the inter-treatment bias as well as the inter-replicate variance. Therefore, we recommend inspecting both of the bias sources in order to apply the most efficient correction method. As an alternative correction strategy, sequential application of different correction approaches is also advised. Copyright © 2014 Elsevier B.V. All rights reserved.

Progress Toward In Vivo Use of siRNAs-II

PubMed Central

Rettig, Garrett R; Behlke, Mark A

2012-01-01

RNA interference (RNAi) has been extensively employed for in vivo research since its use was first demonstrated in mammalian cells 10 years ago. Design rules have improved, and it is now routinely possible to obtain reagents that suppress expression of any gene desired. At the same time, increased understanding of the molecular basis of unwanted side effects has led to the development of chemical modification strategies that mitigate these concerns. Delivery remains the single greatest hurdle to widespread adoption of in vivo RNAi methods. However, exciting advances have been made and new delivery systems under development may help to overcome these barriers. This review discusses advances in RNAi biochemistry and biology that impact in vivo use and provides an overview of select publications that demonstrate interesting applications of these principles. Emphasis is placed on work with synthetic, small interfering RNAs (siRNAs) published since the first installment of this review which appeared in 2006. PMID:22186795

Tibetan medicine "RNSP" in treatment of Alzheimer disease.

PubMed

Shi, Jing-Ming; He, Xue; Lian, Hui-Juan; Yuan, Dong-Ya; Hu, Qun-Ying; Sun, Zheng-Qi; Li, Yan-Song; Zeng, Yu-Wen

2015-01-01

Alzheimer disease (Alzheimer Disease, AD) is one of the most common type in senile dementia. Its main pathological features were that a large number of senile plaques gathered in brain extracellular and tangles fibrosis appeared in nerve cells. Currently, the pathogenesis of AD is still uncertain, and scale investigation and combined brain CT, MRI data were analyzed mainly for clinical diagnosis. Mitigation and improvement of the nervous system activity to interfere with the subsequent behavior of the patients are the main methods for treatment. In clinical no drug can really prevent and cure AD. From the view point of Tibetan medicine studies, Tibetan medicine RNSP has effect on improving memory and repairing the neurons in the brain. In this study, we combined the characteristics of AD pathology, pathogenesis, diagnosis and treatment methods to explore the feasibility of Tibetan medicine RNSP for the treatment of AD to provide new ideas for the diagnosis and treatment of AD.

A Localization-Free Interference and Energy Holes Minimization Routing for Underwater Wireless Sensor Networks.

PubMed

Khan, Anwar; Ahmedy, Ismail; Anisi, Mohammad Hossein; Javaid, Nadeem; Ali, Ihsan; Khan, Nawsher; Alsaqer, Mohammed; Mahmood, Hasan

2018-01-09

Interference and energy holes formation in underwater wireless sensor networks (UWSNs) threaten the reliable delivery of data packets from a source to a destination. Interference also causes inefficient utilization of the limited battery power of the sensor nodes in that more power is consumed in the retransmission of the lost packets. Energy holes are dead nodes close to the surface of water, and their early death interrupts data delivery even when the network has live nodes. This paper proposes a localization-free interference and energy holes minimization (LF-IEHM) routing protocol for UWSNs. The proposed algorithm overcomes interference during data packet forwarding by defining a unique packet holding time for every sensor node. The energy holes formation is mitigated by a variable transmission range of the sensor nodes. As compared to the conventional routing protocols, the proposed protocol does not require the localization information of the sensor nodes, which is cumbersome and difficult to obtain, as nodes change their positions with water currents. Simulation results show superior performance of the proposed scheme in terms of packets received at the final destination and end-to-end delay.

Suppression of emission rates improves sonar performance by flying bats.

PubMed

Adams, Amanda M; Davis, Kaylee; Smotherman, Michael

2017-01-31

Echolocating bats face the challenge of actively sensing their environment through their own emissions, while also hearing calls and echoes of nearby conspecifics. How bats mitigate interference is a long-standing question that has both ecological and technological implications, as biosonar systems continue to outperform man-made sonar systems in noisy, cluttered environments. We recently showed that perched bats decreased calling rates in groups, displaying a behavioral strategy resembling the back-off algorithms used in artificial communication networks to optimize information throughput at the group level. We tested whether free-tailed bats (Tadarida brasiliensis) would employ such a coordinated strategy while performing challenging flight maneuvers, and report here that bats navigating obstacles lowered emission rates when hearing artificial playback of another bat's calls. We measured the impact of acoustic interference on navigation performance and show that the calculated reductions in interference rates are sufficient to reduce interference and improve obstacle avoidance. When bats flew in pairs, each bat responded to the presence of the other as an obstacle by increasing emissions, but hearing the sonar emissions of the nearby bat partially suppressed this response. This behavior supports social cohesion by providing a key mechanism for minimizing mutual interference.

Speech interference and transmission on residential balconies with road traffic noise.

PubMed

Naish, Daniel A; Tan, Andy C C; Nur Demirbilek, F

2013-01-01

Balcony acoustic treatments can mitigate the effects of community road traffic noise. To further investigate, a theoretical study into the effects of balcony acoustic treatment combinations on speech interference and transmission is conducted for various street geometries. Nine different balcony types are investigated using a combined specular and diffuse reflection computer model. Diffusion in the model is calculated using the radiosity technique. The balcony types include a standard balcony with or without a ceiling and with various combinations of parapet, ceiling absorption and ceiling shield. A total of 70 balcony and street geometrical configurations are analyzed with each balcony type, resulting in 630 scenarios. In each scenario the reverberation time, speech interference level (SIL) and speech transmission index (STI) are calculated. These indicators are compared to determine trends based on the effects of propagation path, inclusion of opposite buildings and difference with a reference position outside the balcony. The results demonstrate trends in SIL and STI with different balcony types. It is found that an acoustically treated balcony reduces speech interference. A parapet provides the largest improvement, followed by absorption on the ceiling. The largest reductions in speech interference arise when a combination of balcony acoustic treatments are applied.

Suppression of emission rates improves sonar performance by flying bats

PubMed Central

Adams, Amanda M.; Davis, Kaylee; Smotherman, Michael

2017-01-01

Echolocating bats face the challenge of actively sensing their environment through their own emissions, while also hearing calls and echoes of nearby conspecifics. How bats mitigate interference is a long-standing question that has both ecological and technological implications, as biosonar systems continue to outperform man-made sonar systems in noisy, cluttered environments. We recently showed that perched bats decreased calling rates in groups, displaying a behavioral strategy resembling the back-off algorithms used in artificial communication networks to optimize information throughput at the group level. We tested whether free-tailed bats (Tadarida brasiliensis) would employ such a coordinated strategy while performing challenging flight maneuvers, and report here that bats navigating obstacles lowered emission rates when hearing artificial playback of another bat’s calls. We measured the impact of acoustic interference on navigation performance and show that the calculated reductions in interference rates are sufficient to reduce interference and improve obstacle avoidance. When bats flew in pairs, each bat responded to the presence of the other as an obstacle by increasing emissions, but hearing the sonar emissions of the nearby bat partially suppressed this response. This behavior supports social cohesion by providing a key mechanism for minimizing mutual interference. PMID:28139707

A Localization-Free Interference and Energy Holes Minimization Routing for Underwater Wireless Sensor Networks

PubMed Central

Khan, Anwar; Anisi, Mohammad Hossein; Javaid, Nadeem; Khan, Nawsher; Alsaqer, Mohammed; Mahmood, Hasan

2018-01-01

Interference and energy holes formation in underwater wireless sensor networks (UWSNs) threaten the reliable delivery of data packets from a source to a destination. Interference also causes inefficient utilization of the limited battery power of the sensor nodes in that more power is consumed in the retransmission of the lost packets. Energy holes are dead nodes close to the surface of water, and their early death interrupts data delivery even when the network has live nodes. This paper proposes a localization-free interference and energy holes minimization (LF-IEHM) routing protocol for UWSNs. The proposed algorithm overcomes interference during data packet forwarding by defining a unique packet holding time for every sensor node. The energy holes formation is mitigated by a variable transmission range of the sensor nodes. As compared to the conventional routing protocols, the proposed protocol does not require the localization information of the sensor nodes, which is cumbersome and difficult to obtain, as nodes change their positions with water currents. Simulation results show superior performance of the proposed scheme in terms of packets received at the final destination and end-to-end delay. PMID:29315247

Children's Sleep and Academic Achievement: The Moderating Role of Effortful Control

ERIC Educational Resources Information Center

Diaz, Anjolii; Berger, Rebecca; Valiente, Carlos; Eisenberg, Nancy; VanSchyndel, Sarah K.; Tao, Chun; Spinrad, Tracy; Doane, Leah D.; Thompson, Marilyn S.; Silva, Kassondra M.; Southworth, Jody

2017-01-01

Poor sleep is thought to interfere with children's learning and academic achievement (AA). However, existing research and theory indicate there are factors that may mitigate the academic risk associated with poor sleep. The purpose of this study was to examine the moderating role of children's effortful control (EC) on the relation between sleep…

77 FR 12906 - Notice of Release From Federal Grant Assurance Obligations at Fresno Yosemite International...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-02

... continue to use the land as passive wetlands, which will keep the property vacant and compatible with the... generating potential. The planned land use is for water recharge, ponding basin, and passive wetlands. The property will be kept mitigated to ensure that its passive use does not interfere with airport operations...

Mitigating leakage errors due to cavity modes in a superconducting quantum computer

NASA Astrophysics Data System (ADS)

McConkey, T. G.; Béjanin, J. H.; Earnest, C. T.; McRae, C. R. H.; Pagel, Z.; Rinehart, J. R.; Mariantoni, M.

2018-07-01

A practical quantum computer requires quantum bit (qubit) operations with low error probabilities in extensible architectures. We study a packaging method that makes it possible to address hundreds of superconducting qubits by means of coaxial Pogo pins. A qubit chip is housed in a superconducting box, where both box and chip dimensions lead to unwanted modes that can interfere with qubit operations. We analyze these interference effects in the context of qubit coherent leakage and qubit decoherence induced by damped modes. We propose two methods, half-wave fencing and antinode pinning, to mitigate the resulting errors by detuning the resonance frequency of the modes from the qubit frequency. We perform electromagnetic field simulations indicating that the resonance frequency of the modes increases with the number of installed pins and can be engineered to be significantly higher than the highest qubit frequency. We estimate that the error probabilities and decoherence rates due to suitably shifted modes in realistic scenarios can be up to two orders of magnitude lower than the state-of-the-art superconducting qubit error and decoherence rates. Our methods can be extended to different types of packages that do not rely on Pogo pins. Conductive bump bonds, for example, can serve the same purpose in qubit architectures based on flip chip technology. Metalized vias, instead, can be used to mitigate modes due to the increasing size of the dielectric substrate on which qubit arrays are patterned.

Detecting and mitigating wind turbine clutter for airspace radar systems.

PubMed

Wang, Wen-Qin

2013-01-01

It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results.

Detecting and Mitigating Wind Turbine Clutter for Airspace Radar Systems

PubMed Central

2013-01-01

It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. PMID:24385880

Safe use of cellular telephones in hospitals: fundamental principles and case studies.

PubMed

Cohen, Ted; Ellis, Willard S; Morrissey, Joseph J; Bakuzonis, Craig; David, Yadin; Paperman, W David

2005-01-01

Many industries and individuals have embraced cellular telephones. They provide mobile, synchronous communication, which could hypothetically increase the efficiency and safety of inpatient healthcare. However, reports of early analog cellular telephones interfering with critical life-support machines had led many hospitals to strictly prohibit cellular telephones. A literature search revealed that individual hospitals now are allowing cellular telephone use with various policies to prevent electromagnetic interference with medical devices. The fundamental principles underlying electromagnetic interference are immunity, frequency, modulation technology, distance, and power Electromagnetic interference risk mitigation methods based on these principles have been successfully implemented. In one case study, a minimum distance between cellular telephones and medical devices is maintained, with restrictions in critical areas. In another case study, cellular telephone coverage is augmented to automatically control the power of the cellular telephone. While no uniform safety standard yet exists, cellular telephones can be safely used in hospitals when their use is managed carefully.

Analysis of OFDMA receiver with carrier frequency offset and common carrier frequency offset (CCFO)

NASA Astrophysics Data System (ADS)

Gauni, Sabitha; Kumar, R.

2013-01-01

The technique of Orthogonal frequency multiplexing (OFDM) is used to mitigate the multipath effects and to achieve better data rate. When these systems are extended to enable multiple access wireless multimedia communications they are more beneficial. The performance of the OFDM systems degrades with frequency offset and phase offset. The OFDM multiple access (OFDMA) technology allots groups of the OFDM subcarriers allocated to different users for transmission. In this paper we study the interference effects of the individual subcarriers with the neighbouring subcarriers which also plays a role in the system degradation is termed as Multiuser Interference (MUI). The effect of Carrier frequency offset (CFO) on these systems is also taken in account. There are conventional CFO compensation methods for OFDMA systems the CFOs are usually compensated by directly eliminating the intercarrier interference (ICI) caused by the residual CFOs for individual users.

Aboriginal Children and Their Caregivers Living with Low Income: Outcomes from a Two-Generation Preschool Program

ERIC Educational Resources Information Center

Benzies, Karen; Tough, Suzanne; Edwards, Nancy; Mychasiuk, Richelle; Donnelly, Carlene

2011-01-01

The development of preschool children of Aboriginal heritage is jeopardized by the inter-generational transmission of risk that has created, and continues to create, social disadvantage. Early intervention programs are intended to mitigate the impact of social disadvantage. Yet, evidence of the effectiveness of these programs for children of…

Iterative Overlap FDE for Multicode DS-CDMA

NASA Astrophysics Data System (ADS)

Takeda, Kazuaki; Tomeba, Hiromichi; Adachi, Fumiyuki

Recently, a new frequency-domain equalization (FDE) technique, called overlap FDE, that requires no GI insertion was proposed. However, the residual inter/intra-block interference (IBI) cannot completely be removed. In addition to this, for multicode direct sequence code division multiple access (DS-CDMA), the presence of residual interchip interference (ICI) after FDE distorts orthogonality among the spreading codes. In this paper, we propose an iterative overlap FDE for multicode DS-CDMA to suppress both the residual IBI and the residual ICI. In the iterative overlap FDE, joint minimum mean square error (MMSE)-FDE and ICI cancellation is repeated a sufficient number of times. The bit error rate (BER) performance with the iterative overlap FDE is evaluated by computer simulation.

47 CFR 25.213 - Inter-Service coordination requirements for the 1.6/2.4 GHz mobile-satellite service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... radio astronomy service in the 1610.6-1613.8 MHz band against interference from 1.6/2.4 GHz Mobile... System. During periods of radio astronomy observations, land mobile earth stations shall not operate when... astronomy sites: Observatory Latitude (DMS) Longitude (DMS) Arecibo, PR 18 20 46 66 45 11 Green Bank...

47 CFR 25.213 - Inter-Service coordination requirements for the 1.6/2.4 GHz mobile-satellite service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... radio astronomy service in the 1610.6-1613.8 MHz band against interference from 1.6/2.4 GHz Mobile... System. During periods of radio astronomy observations, land mobile earth stations shall not operate when... astronomy sites: Observatory Latitude (DMS) Longitude (DMS) Arecibo, PR 18 20 46 66 45 11 Green Bank...

47 CFR 25.213 - Inter-Service coordination requirements for the 1.6/2.4 GHz mobile-satellite service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... radio astronomy service in the 1610.6-1613.8 MHz band against interference from 1.6/2.4 GHz Mobile... System. During periods of radio astronomy observations, land mobile earth stations shall not operate when... astronomy sites: Observatory Latitude (DMS) Longitude (DMS) Arecibo, PR 18 20 46 66 45 11 Green Bank...

Two-pole microring weight banks.

PubMed

Tait, Alexander N; Wu, Allie X; Ferreira de Lima, Thomas; Nahmias, Mitchell A; Shastri, Bhavin J; Prucnal, Paul R

2018-05-15

Weighted addition is an elemental multi-input to single-output operation that can be implemented with high-performance photonic devices. Microring (MRR) weight banks bring programmable weighted addition to silicon photonics. Prior work showed that their channel limits are affected by coherent inter-channel effects that occur uniquely in weight banks. We fabricate two-pole designs that exploit this inter-channel interference in a way that is robust to dynamic tuning and fabrication variation. Scaling analysis predicts a channel count improvement of 3.4-fold, which is substantially greater than predicted by incoherent analysis used in conventional MRR devices. Advances in weight bank design expand the potential of reconfigurable analog photonic networks and multivariate microwave photonics.

Tonic Inhibitory Control of Dentate Gyrus Granule Cells by α5-Containing GABAA Receptors Reduces Memory Interference.

PubMed

Engin, Elif; Zarnowska, Ewa D; Benke, Dietmar; Tsvetkov, Evgeny; Sigal, Maksim; Keist, Ruth; Bolshakov, Vadim Y; Pearce, Robert A; Rudolph, Uwe

2015-10-07

Interference between similar or overlapping memories formed at different times poses an important challenge on the hippocampal declarative memory system. Difficulties in managing interference are at the core of disabling cognitive deficits in neuropsychiatric disorders. Computational models have suggested that, in the normal brain, the sparse activation of the dentate gyrus granule cells maintained by tonic inhibitory control enables pattern separation, an orthogonalization process that allows distinct representations of memories despite interference. To test this mechanistic hypothesis, we generated mice with significantly reduced expression of the α5-containing GABAA (α5-GABAARs) receptors selectively in the granule cells of the dentate gyrus (α5DGKO mice). α5DGKO mice had reduced tonic inhibition of the granule cells without any change in fast phasic inhibition and showed increased activation in the dentate gyrus when presented with novel stimuli. α5DGKO mice showed impairments in cognitive tasks characterized by high interference, without any deficiencies in low-interference tasks, suggesting specific impairment of pattern separation. Reduction of fast phasic inhibition in the dentate gyrus through granule cell-selective knock-out of α2-GABAARs or the knock-out of the α5-GABAARs in the downstream CA3 area did not detract from pattern separation abilities, which confirms the anatomical and molecular specificity of the findings. In addition to lending empirical support to computational hypotheses, our findings have implications for the treatment of interference-related cognitive symptoms in neuropsychiatric disorders, particularly considering the availability of pharmacological agents selectively targeting α5-GABAARs. Interference between similar memories poses a significant limitation on the hippocampal declarative memory system, and impaired interference management is a cognitive symptom in many disorders. Thus, understanding mechanisms of successful interference management or processes that can lead to interference-related memory problems has high theoretical and translational importance. This study provides empirical evidence that tonic inhibition in the dentate gyrus (DG), which maintains sparseness of neuronal activation in the DG, is essential for management of interference. The specificity of findings to tonic, but not faster, more transient types of neuronal inhibition and to the DG, but not the neighboring brain areas, is presented through control experiments. Thus, the findings link interference management to a specific mechanism, proposed previously by computational models. Copyright © 2015 the authors 0270-6474/15/3513699-15$15.00/0.

Implicit and Explicit Number-Space Associations Differentially Relate to Interference Control in Young Adults With ADHD

PubMed Central

Georges, Carrie; Hoffmann, Danielle; Schiltz, Christine

2018-01-01

Behavioral evidence for the link between numerical and spatial representations comes from the spatial-numerical association of response codes (SNARC) effect, consisting in faster reaction times to small/large numbers with the left/right hand respectively. The SNARC effect is, however, characterized by considerable intra- and inter-individual variability. It depends not only on the explicit or implicit nature of the numerical task, but also relates to interference control. To determine whether the prevalence of the latter relation in the elderly could be ascribed to younger individuals’ ceiling performances on executive control tasks, we determined whether the SNARC effect related to Stroop and/or Flanker effects in 26 young adults with ADHD. We observed a divergent pattern of correlation depending on the type of numerical task used to assess the SNARC effect and the type of interference control measure involved in number-space associations. Namely, stronger number-space associations during parity judgments involving implicit magnitude processing related to weaker interference control in the Stroop but not Flanker task. Conversely, stronger number-space associations during explicit magnitude classifications tended to be associated with better interference control in the Flanker but not Stroop paradigm. The association of stronger parity and magnitude SNARC effects with weaker and better interference control respectively indicates that different mechanisms underlie these relations. Activation of the magnitude-associated spatial code is irrelevant and potentially interferes with parity judgments, but in contrast assists explicit magnitude classifications. Altogether, the present study confirms the contribution of interference control to number-space associations also in young adults. It suggests that magnitude-associated spatial codes in implicit and explicit tasks are monitored by different interference control mechanisms, thereby explaining task-related intra-individual differences in number-space associations. PMID:29881363

Work-family conflict and sleep disturbance: the Malaysian working women study

PubMed Central

AAZAMI, Sanaz; MOZAFARI, Mosayeb; SHAMSUDDIN, Khadijah; AKMAL, Syaqirah

2015-01-01

This study aimed at assessing effect of the four dimensions of work-family conflicts (strain and time-based work interference into family and family interference into work) on sleep disturbance in Malaysian working women. This cross-sectional study was conducted among 325 Malaysian married working women. Multiple-stage simple random sampling method was used to recruit women from public service departments of Malaysia. Self-administrated questionnaires were used to measure the study variables and data were analyzed using SPSS version 21. We found that high level of the four dimensions of work-family conflicts significantly increase sleep disturbance. Our analyses also revealed an age-dependent effect of the work-family conflict on sleep disturbance. Women in their 20 to 30 yr old suffer from sleep disturbance due to high level of time-based and strain-based work-interference into family. However, the quality of sleep among women aged 30–39 were affected by strain-based family-interference into work. Finally, women older than 40 yr had significantly disturbed sleep due to strain-based work-interference into family as well as time-based family interference into work. Our findings showed that sleep quality of working women might be disturbed by experiencing high level of work-family conflict. However, the effects of inter-role conflicts on sleep varied among different age groups. PMID:26423332

RNA interference of argininosuccinate synthetase restores sensitivity to recombinant arginine deiminase (rADI) in resistant cancer cells

PubMed Central

2011-01-01

Background Sensitivity of cancer cells to recombinant arginine deiminase (rADI) depends on expression of argininosuccinate synthetase (AS), a rate-limiting enzyme in synthesis of arginine from citrulline. To understand the efficiency of RNA interfering of AS in sensitizing the resistant cancer cells to rADI, the down regulation of AS transiently and permanently were performed in vitro, respectively. Methods We studied the use of down-regulation of this enzyme by RNA interference in three human cancer cell lines (A375, HeLa, and MCF-7) as a way to restore sensitivity to rADI in resistant cells. The expression of AS at levels of mRNA and protein was determined to understand the effect of RNA interference. Cell viability, cell cycle, and possible mechanism of the restore sensitivity of AS RNA interference in rADI treated cancer cells were evaluated. Results AS DNA was present in all cancer cell lines studied, however, the expression of this enzyme at the mRNA and protein level was different. In two rADI-resistant cell lines, one with endogenous AS expression (MCF-7 cells) and one with induced AS expression (HeLa cells), AS small interference RNA (siRNA) inhibited 37-46% of the expression of AS in MCF-7 cells. ASsiRNA did not affect cell viability in MCF-7 which may be due to the certain amount of residual AS protein. In contrast, ASsiRNA down-regulated almost all AS expression in HeLa cells and caused cell death after rADI treatment. Permanently down-regulated AS expression by short hairpin RNA (shRNA) made MCF-7 cells become sensitive to rADI via the inhibition of 4E-BP1-regulated mTOR signaling pathway. Conclusions Our results demonstrate that rADI-resistance can be altered via AS RNA interference. Although transient enzyme down-regulation (siRNA) did not affect cell viability in MCF-7 cells, permanent down-regulation (shRNA) overcame the problem of rADI-resistance due to the more efficiency in AS silencing. PMID:21453546

The electromagnetic interference of mobile phones on the function of a γ-camera.

PubMed

Javadi, Hamid; Azizmohammadi, Zahra; Mahmoud Pashazadeh, Ali; Neshandar Asli, Isa; Moazzeni, Taleb; Baharfar, Nastaran; Shafiei, Babak; Nabipour, Iraj; Assadi, Majid

2014-03-01

The aim of the present study is to evaluate whether or not the electromagnetic field generated by mobile phones interferes with the function of a SPECT γ-camera during data acquisition. We tested the effects of 7 models of mobile phones on 1 SPECT γ-camera. The mobile phones were tested when making a call, in ringing mode, and in standby mode. The γ-camera function was assessed during data acquisition from a planar source and a point source of Tc with activities of 10 mCi and 3 mCi, respectively. A significant visual decrease in count number was considered to be electromagnetic interference (EMI). The percentage of induced EMI with the γ-camera per mobile phone was in the range of 0% to 100%. The incidence of EMI was mainly observed in the first seconds of ringing and then mitigated in the following frames. Mobile phones are portable sources of electromagnetic radiation, and there is interference potential with the function of SPECT γ-cameras leading to adverse effects on the quality of the acquired images.

Locata Performance Evaluation in the Presence of Wide- and Narrow-Band Interference

NASA Astrophysics Data System (ADS)

Khan, Faisal A.; Rizos, Chris; Dempster, Andrew G.

Classically difficult positioning environments often call for augmentation technology to assist the GPS, or more generally the Global Navigation Satellite System (GNSS) technology. The ground-based ranging technology offers augmentation, and even replacement, to GPS in such environments. However, like any other system relying on wireless technology, a Locata positioning network also faces issues in the presence of RF interference (RFI). This problem is magnified due to the fact that Locata operates in the licence-free 2·4 GHz Industrial, Scientific and Medical (ISM) band. The licence-free nature of this band attracts a much larger number of devices using a wider range of signal types than for licensed bands, resulting in elevation of the noise floor. Also, harmonics from out-of-band signals can act as potential interferers. WiFi devices operating in this band have been identified as the most likely potential interferer, due partially to their use of the whole ISM band, but also because Locata applications often also may use a wireless network. This paper evaluates the performance of Locata in the presence of both narrow- and wide-band interfering signals. Effects of received interference on both raw measurements and final solutions are reported and analysed. Test results show that Locata performance degrades in the presence of received interference. It is also identified that high levels of received interference can affect Locata carriers even if the interference is not in co-frequency situation with the affected carrier. Finally, Locata characteristics have been identified which can be exploited to mitigate RFI issues.

Digital music players cause interference with interrogation telemetry for pacemakers and implantable cardioverter-defibrillators without affecting device function.

PubMed

Webster, Gregory; Jordao, Ligia; Martuscello, Maria; Mahajan, Tarun; Alexander, Mark E; Cecchin, Frank; Triedman, John K; Walsh, Edward P; Berul, Charles I

2008-04-01

Concern exists regarding the potential electromagnetic interaction between pacemakers, implantable cardioverter-defibrillators (ICDs) and digital music players (DMPs). A preliminary study reported interference in 50% of patients whose devices were interrogated near Apple iPods. Given the high prevalence of DMP use among young patients, we sought to define the nature of interference from iPods and evaluate other DMPs. Four DMPs (Apple Nano, Apple Video, SanDisk Sansa and Microsoft Zune) were evaluated against pacemakers and ICDs (PM/ICD). Along with continuous monitoring, we recorded a baseline ECG strip, sensing parameters and lead impedance at baseline and for each device. Among 51 patients evaluated (age 6 to 60 years, median 22), there was no interference with intrinsic device function. Interference with the programmer occurred in 41% of the patients. All four DMPs caused programmer interference, including disabled communication between the PM/ICD and programmer, noise in the ECG channel, and lost marker channel indicators. Sensing parameters and lead impedances exhibited no more than baseline variability. When the DMPs were removed six inches, there were no further programmer telemetry interactions. Contrary to a prior report, we did not identify any evidence for electromagnetic interference between a selection of DMPs and intrinsic function of PM/ICDs. The DMPs did sometimes interfere with device-programmer communication, but not in a way that compromised device function. Therefore, we recommend that DMPs not be used during device interrogation, but suggest that there is reassuring counterevidence to mitigate the current high level of concern for interactions between DMPs and implantable cardiac rhythm devices.

Clustering-based energy-saving algorithm in ultra-dense network

NASA Astrophysics Data System (ADS)

Huang, Junwei; Zhou, Pengguang; Teng, Deyang; Zhang, Renchi; Xu, Hao

2017-06-01

In Ultra-dense Networks (UDN), dense deployment of low power small base stations will cause serious small cells interference and a large amount of energy consumption. The purpose of this paper is to explore the method of reducing small cells interference and energy saving system in UDN, and we innovatively propose a sleep-waking-active (SWA) scheme. The scheme decreases the user outage causing by failure to detect users’ service requests, shortens the opening time of active base stations directly switching to sleep mode; we further proposes a Vertex Surrounding Clustering(VSC) algorithm, which first colours the small cells with the most strongest interference and next extends to the adjacent small cells. VSC algorithm can use the least colour to stain the small cell, reduce the number of iterations and promote the efficiency of colouring. The simulation results show that SWA scheme can effectively improve the system Energy Efficiency (EE), the VSC algorithm can reduce the small cells interference and optimize the users’ Spectrum Efficiency (SE) and throughput.

RFI Detection and Mitigation using Independent Component Analysis as a Pre-Processor

NASA Technical Reports Server (NTRS)

Schoenwald, Adam J.; Gholian, Armen; Bradley, Damon C.; Wong, Mark; Mohammed, Priscilla N.; Piepmeier, Jeffrey R.

2016-01-01

Radio-frequency interference (RFI) has negatively impacted scientific measurements of passive remote sensing satellites. This has been observed in the L-band radiometers Soil Moisture and Ocean Salinity (SMOS), Aquarius and more recently, Soil Moisture Active Passive (SMAP). RFI has also been observed at higher frequencies such as K band. Improvements in technology have allowed wider bandwidth digital back ends for passive microwave radiometry. A complex signal kurtosis radio frequency interference detector was developed to help identify corrupted measurements. This work explores the use of Independent Component Analysis (ICA) as a blind source separation (BSS) technique to pre-process radiometric signals for use with the previously developed real and complex signal kurtosis detectors.

BIOTIN INTERFERENCE WITH ROUTINE CLINICAL IMMUNOASSAYS: UNDERSTAND THE CAUSES AND MITIGATE THE RISKS.

PubMed

Samarasinghe, Shanika; Meah, Farah; Singh, Vinita; Basit, Arshi; Emanuele, Nicholas; Emanuele, Mary Ann; Mazhari, Alaleh; Holmes, Earle W

2017-08-01

The objectives of this report are to review the mechanisms of biotin interference with streptavidin/biotin-based immunoassays, identify automated immunoassay systems vulnerable to biotin interference, describe how to estimate and minimize the risk of biotin interference in vulnerable assays, and review the literature pertaining to biotin interference in endocrine function tests. The data in the manufacturer's "Instructions for Use" for each of the methods utilized by seven immunoassay system were evaluated. We also conducted a systematic search of PubMed/MEDLINE for articles containing terms associated with biotin interference. Available original reports and case series were reviewed. Abstracts from recent scientific meetings were also identified and reviewed. The recent, marked, increase in the use of over-the-counter, high-dose biotin supplements has been accompanied by a steady increase in the number of reports of analytical interference by exogenous biotin in the immunoassays used to evaluate endocrine function. Since immunoassay methods of similar design are also used for the diagnosis and management of anemia, malignancies, autoimmune and infectious diseases, cardiac damage, etc., biotin-related analytical interference is a problem that touches every area of internal medicine. It is important for healthcare personnel to become more aware of immunoassay methods that are vulnerable to biotin interference and to consider biotin supplements as potential sources of falsely increased or decreased test results, especially in cases where a lab result does not correlate with the clinical scenario. FDA = U.S. Food & Drug Administration FT3 = free tri-iodothyronine FT4 = free thyroxine IFUs = instructions for use LH = luteinizing hormone PTH = parathyroid hormone SA/B = streptavidin/biotin TFT = thyroid function test TSH = thyroid-stimulating hormone.

47 CFR 95.206 - (R/C Rule 6) Are there any special restrictions on the location of my R/C station?

Code of Federal Regulations, 2011 CFR

2011-10-01

... COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio... operated in such a manner as to raise environmental problems, under § 1.1307 of this chapter, you must... order to resolve or mitigate any potential interference problem with the Arecibo Observatory. If the...

47 CFR 95.206 - (R/C Rule 6) Are there any special restrictions on the location of my R/C station?

Code of Federal Regulations, 2010 CFR

2010-10-01

... COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio... operated in such a manner as to raise environmental problems, under § 1.1307 of this chapter, you must... order to resolve or mitigate any potential interference problem with the Arecibo Observatory. If the...

Long-range transcriptional interference in E. coli used to construct a dual positive selection system for genetic switches

PubMed Central

Hoffmann, Stefan A.; Kruse, Sabrina M.; Arndt, Katja M.

2016-01-01

Abstract We have investigated transcriptional interference between convergent genes in E. coli and demonstrate substantial interference for inter-promoter distances of as far as 3 kb. Interference can be elicited by both strong σ70 dependent and T7 promoters. In the presented design, a strong promoter driving gene expression of a ‘forward’ gene interferes with the expression of a ‘reverse’ gene by a weak promoter. This arrangement allows inversely correlated gene expression without requiring further regulatory components. Thus, modulation of the activity of the strong promoter alters expression of both the forward and the reverse gene. We used this design to develop a dual selection system for conditional operator site binding, allowing positive selection both for binding and for non-binding to DNA. This study demonstrates the utility of this novel system using the Lac repressor as a model protein for conditional DNA binding, and spectinomycin and chloramphenicol resistance genes as positive selection markers in liquid culture. Randomized LacI libraries were created and subjected to subsequent dual selection, but mispairing IPTG and selection cues in respect to the wild-type LacI response, allowing the isolation of a LacI variant with a reversed IPTG response within three rounds of library generation and dual selection. PMID:26932362

Aquarius Radiometer RFI Detection, Mitigation, and Impact Assessment

NASA Technical Reports Server (NTRS)

Ruf, Christopher; Chen, David; Le Vine, David; de Matthaeis, Paolo; Piepmeier, Jeffrey

2012-01-01

The Aquarius/SAC-D satellite was launched on 10 June 2011 into a sun-synchronous polar orbit and the Aquarius microwave radiometers [1] became operational on 25 August 2011. Since that time, it has been measuring brightness temperatures at 1.4 GHz with vertical, horizontal and 3rd Stokes polarizations . Beginning well before the launch, there has been the concern that Radio Frequency Interference (RFI) could have an appreciable presence. This concern was initiated by, among other things, its prevalence in both early [2] and more recent [3,4] aircraft field experiments using 1.4 GHz radiometers, as well as by the strong RFI environment encountered during the recent ESA SMOS mission, also at 1.4 GHz [5]. As a result, a number of methods for RFI detection and mitigation have been developed and tested. One in particular, "glitch detection" and "pulse blanking" mitigation has been adapted for use by Aquarius [6, 7]. The early on-orbit performance of the Aquarius RFI detection and mitigation algorithm is presented here, together with an assessment of the global RFI environment at 1.4 GHz which can be derived from the Aquarius results.

Recovery of inter-row shading losses using differential power-processing submodule DC–DC converters

DOE PAGES

Doubleday, Kate; Choi, Beomseok; Maksimovic, Dragan; ...

2016-06-17

Large commercial photovoltaic (PV) systems can experience regular and predictable energy loss due to both inter-row shading and reduced diffuse irradiance in tightly spaced arrays. This article investigates the advantages of replacing bypass diodes with submodule-integrated DC-DC converters (subMICs) to mitigate these losses. Yearly simulations of commercial-scale PV systems were conducted considering a range of row-to-row pitches. In the limit case of array spacing (unity ground coverage), subMICs can confer a 7% increase in annual energy output and peak energy density (kW h/m 2). Simulation results are based on efficiency assumptions experimentally confirmed by prototype submodule differential power-processing converters.

The Role of IT Assets in Organizational Accumulation and Appropriation of Social Capital for Business Risk Mitigation and Inter-Organizational Innovation

ERIC Educational Resources Information Center

Simha, Anand N.

2013-01-01

This dissertation comprises of three essays examining the interplay of information technology with various social processes that typically inhabit the organizational space. The first essay presents the concept of a Relationship Memory System (RMS). This study uses grounded theory methodology and interview data collected at a global…

Effects of stand and inter-specific stocking on maximizing standing tree carbon stocks in the eastern United States

Treesearch

Christopher W. Woodall; Anthony W. D' Amato; John B. Bradford; Andrew O. Finley

2011-01-01

There is expanding interest in management strategies that maximize forest carbon (C) storage to mitigate increased atmospheric carbon dioxide. The tremendous tree species diversity and range of stand stocking found across the eastern United States presents a challenge for determining optimal combinations for the maximization of standing tree C storage. Using a...

Comparison of national space debris mitigation standards

NASA Astrophysics Data System (ADS)

Kato, A.

2001-01-01

Several national organizations of the space faring nations have established Space Debris Mitigation Standards or Handbooks to promote efforts to deal with the space debris issue. This paper introduces the characteristics of each document and compares the structure, items and level of requirements. The contents of these standards may be slightly different from each other but the fundamental principles are almost the same; they are (1) prevention of on-orbit breakups, (2) removal of mission terminated spacecraft from the useful orbit regions, and (3) limiting the objects released during normal operations. The Inter-Agency Space Debris Coordination Committee has contributed considerably to this trend. The Committee also found out by its recent survey that some commercial companies have begun to adopt the debris mitigation measures for their projects. However, the number of organizations that have initiated this kind of self-control is still limited, so the next challenge of the Committee is to promote the Space Debris Mitigation Guidelines world-wide. IADC initiated this project in October 1999 and a draft is being circulated among the member agencies.

RGS16 inhibits breast cancer cell growth by mitigating phosphatidylinositol 3-kinase signaling.

PubMed

Liang, Genqing; Bansal, Geetanjali; Xie, Zhihui; Druey, Kirk M

2009-08-07

Aberrant activity of the phosphatidylinositol 3-kinase (PI3K) pathway supports growth of many tumors including those of breast, lung, and prostate. Resistance of breast cancer cells to targeted chemotherapies including tyrosine kinase inhibitors (TKI) has been linked to persistent PI3K activity, which may in part be due to increased membrane expression of epidermal growth factor (EGF) receptors (HER2 and HER3). Recently we found that proteins of the RGS (regulator of G protein signaling) family suppress PI3K activity downstream of the receptor by sequestering its p85alpha subunit from signaling complexes. Because a substantial percentage of breast tumors have RGS16 mutations and reduced RGS16 protein expression, we investigated the link between regulation of PI3K activity by RGS16 and breast cancer cell growth. RGS16 overexpression in MCF7 breast cancer cells inhibited EGF-induced proliferation and Akt phosphorylation, whereas shRNA-mediated extinction of RGS16 augmented cell growth and resistance to TKI treatment. Exposure to TKI also reduced RGS16 expression in MCF7 and BT474 cell lines. RGS16 bound the amino-terminal SH2 and inter-SH2 domains of p85alpha and inhibited its interaction with the EGF receptor-associated adapter protein Gab1. These results suggest that the loss of RGS16 in some breast tumors enhances PI3K signaling elicited by growth factors and thereby promotes proliferation and TKI evasion downstream of HER activation.

Identification and mitigation of interference sources present in SSB-based wireless MRI receiver arrays

PubMed Central

Riffe, Matthew J.; Twieg, Michael D.; Gudino, Natalia; Blumenthal, Colin J.; Heilman, Jeremy A.; Griswold, Mark A.

2013-01-01

Purpose Single sideband amplitude modulation (SSB) is an appealing platform for highly parallel wireless MRI detector arrays because the spacing between channels is ideally limited only by the MRI signal bandwidth. However this assumes that no other sources of interference are present outside that bandwidth. This work investigates the practical interference between multiple SSB-encoded MRI signals. Methods Noise from coil preamplifiers and carrier bleed-through are identified as sources of interference. Two different SSB systems were designed for 1.5T with different noise filtering properties. We show how the differences between the filtered noise profiles impact the received MR signal’s dynamic range (DRsig) and image signal-to-noise ratio (SNR) through simulation, bench measurements, and phantom imaging experiments. Results When operating individually in the MR scanner, both SSB systems were shown to minimally impact the original DRsig and SNR. On the other hand, when all eight channels were operating simultaneously, an average SNR loss was observed to be 12% in the one system, while a second system with more complex filtering was able to achieve a 3% loss in SNR. Conclusion Successful wireless transmission of multiple SSB-encoded MRI signals is possible as long as channel interference is properly managed through design and simulation. PMID:23413242

New developments in the treatment of multiple myeloma - clinical utility of daratumumab.

PubMed

McEllistrim, Cian; Krawczyk, Janusz; O'Dwyer, Michael E

2017-01-01

Multiple myeloma is a clonal disorder of plasma cells that is currently considered incurable. CD38 is a 46 kDa type II transmembrane glycoprotein that is highly expressed on myeloma cells. Daratumumab is a first in-class human IgG1 monoclonal antibody that targets CD38, and has antimyeloma effects through several mechanisms. Single-agent trials show surprising activity in heavily pretreated myeloma patients. Trials in the relapsed setting, where daratumumab is added to lenalidomide and dexamethasone or bortezomib and dexamethasone, have demonstrated significantly improved progression-free survival with acceptable toxicity. In this review, we discuss the mechanism of action, pharmacology and pharmacokinetics of daratumumab and review the available clinical data in detail. We examine how daratumumab interferes with transfusion testing due to the expression of CD38 on the red blood cells, leading to potential difficulties releasing blood products. Daratumumab also affects disease assessments in multiple myeloma, including serum protein electrophoresis, immunofixation and flow cytometry. Strategies to mitigate these effects are discussed. The optimal use of daratumumab has yet to be decided, and several trials are ongoing in the relapsed and upfront setting. We discuss the potential upfront role of this exciting therapy, which has significant potential for increased minimal residual disease negativity and improved progression-free survival even in high-risk groups.

New developments in the treatment of multiple myeloma – clinical utility of daratumumab

PubMed Central

McEllistrim, Cian; Krawczyk, Janusz; O’Dwyer, Michael E

2017-01-01

Multiple myeloma is a clonal disorder of plasma cells that is currently considered incurable. CD38 is a 46 kDa type II transmembrane glycoprotein that is highly expressed on myeloma cells. Daratumumab is a first in-class human IgG1 monoclonal antibody that targets CD38, and has antimyeloma effects through several mechanisms. Single-agent trials show surprising activity in heavily pretreated myeloma patients. Trials in the relapsed setting, where daratumumab is added to lenalidomide and dexamethasone or bortezomib and dexamethasone, have demonstrated significantly improved progression-free survival with acceptable toxicity. In this review, we discuss the mechanism of action, pharmacology and pharmacokinetics of daratumumab and review the available clinical data in detail. We examine how daratumumab interferes with transfusion testing due to the expression of CD38 on the red blood cells, leading to potential difficulties releasing blood products. Daratumumab also affects disease assessments in multiple myeloma, including serum protein electrophoresis, immunofixation and flow cytometry. Strategies to mitigate these effects are discussed. The optimal use of daratumumab has yet to be decided, and several trials are ongoing in the relapsed and upfront setting. We discuss the potential upfront role of this exciting therapy, which has significant potential for increased minimal residual disease negativity and improved progression-free survival even in high-risk groups. PMID:28442888

The Influence of Nicotine on Lung Tumor Growth, Cancer Chemotherapy, and Chemotherapy-Induced Peripheral Neuropathy.

PubMed

Kyte, S Lauren; Gewirtz, David A

2018-06-04

Studies in animal models have suggested that nicotine, an agonist of nicotinic acetylcholine receptors (nAChRs), may have the potential to prevent and/or reverse the peripheral neuropathy induced by cancer chemotherapeutic drugs, such as paclitaxel and oxaliplatin. However, a large body of evidence suggests that nicotine may also stimulate lung tumor growth and/or interfere with the effectiveness of cancer chemotherapy. While the reported proliferative effects of nicotine are highly variable, the antagonism of antitumor drug efficacy is more consistent, although this latter effect has been demonstrated primarily in cell culture studies. In contrast, in vitro and in vivo studies from our own laboratory indicate that nicotine fails to enhance the growth of non-small cell lung cancer cells or attenuate the effects of chemotherapy (paclitaxel). Given the inconsistencies in the literature, coupled with our own findings, the weight of evidence suggests that caution may be warranted in proposing to utilize nicotine to mitigate chemotherapy-induced peripheral neuropathy in cancer patients receiving chemotherapy. Conversely, clinical trials could be performed in patients who have completed therapy and are considered to be disease-free to determine whether nicotine, in the form of commercially available patches or gum, is effective in alleviating peripheral neuropathy symptoms. The American Society for Pharmacology and Experimental Therapeutics.

Cognitive software defined radar: waveform design for clutter and interference suppression

NASA Astrophysics Data System (ADS)

Kirk, Benjamin H.; Owen, Jonathan W.; Narayanan, Ram M.; Blunt, Shannon D.; Martone, Anthony F.; Sherbondy, Kelly D.

2017-05-01

Clutter and radio frequency interference (RFI) are prevalent issues in the field of radar and are specifically of interest to of cognitive radar. Here, methods for applying and testing the utility of cognitive radar for clutter and RFI mitigation are explored. Using the adaptable transmit capability, environmental database, and general "awareness" of a cognitive radar system (i.e. spectrum sensing, geographical location, etc.), a matched waveform is synthesized that improves the signal-to-clutter ratio (SCR), assuming at least an estimate of the target response and the environmental clutter response are known a prior i. RFI may also be mitigated by sensing the RF spectrum and adapting the transmit center frequency and bandwidth using methods that optimize bandwidth and signal-to-interference plus noise ratio (SINR) (i.e. the spectrum sensing, multi-objective (SS-MO) algorithm). The improvement is shown by a decrease in the noise floor. The above methods' effectiveness are examined via a test-bed developed around a software defined radio (SDR). Testing and the general use of commercial off the shelf (COTS) devices are desirable for their cost effectiveness, general ease of use, as well as technical and community support, but these devices provide design challenges in order to be effective. The universal software radio peripheral (USRP) X310 SDR is a relatively cheap and portable device that has all the system components of a basic cognitive radar. Design challenges of the SDR include phase coherency between channels, bandwidth limitations, dynamic range, and speed of computation and data communication / recording.

Cell volume and plasma membrane osmotic water permeability in epithelial cell layers measured by interferometry.

PubMed

Farinas, J; Verkman, A S

1996-12-01

The development of strategies to measure plasma membrane osmotic water permeability (Pf) in epithelial cells has been motivated by the identification of a family of molecular water channels. A general approach utilizing interferometry to measure cell shape and volume was developed and applied to measure Pf in cell layers. The method is based on the cell volume dependence of optical path length (OPL) for a light beam passing through the cell. The small changes in OPL were measured by interferometry. A mathematical model was developed to relate the interference signal to cell volume changes for cells of arbitrary shape and size. To validate the model, a Mach-Zehnder interference microscope was used to image OPL in an Madin Darby Canine Kidney (MDCK) cell layer and to reconstruct the three-dimensional cell shape (OPL resolution < lambda/25). As predicted by the model, a doubling of cell volume resulted in a change in OPL that was proportional to the difference in refractive indices between water and the extracellular medium. The time course of relative cell volume in response to an osmotic gradient was computed from serial interference images. To measure cell volume without microscopy and image analysis, a Mach-Zehnder interferometer was constructed in which one of two interfering laser beams passed through a flow chamber containing the cell layer. The interference signal in response to an osmotic gradient was analyzed to quantify the time course of relative cell volume. The calculated MDCK cell plasma membrane Pf of 6.1 x 10(-4) cm/s at 24 degrees C agreed with that obtained by interference microscopy and by a total internal reflection fluorescence method. Interferometry was also applied to measure the apical plasma membrane water permeability of intact toad urinary bladder; Pf increased fivefold after forskolin stimulation to 0.04 cm/s at 23 degrees C. These results establish and validate the application of interferometry to quantify cell volume and osmotic water permeability in cell layers.

Role of tool marks inside spherical mitigation pit fabricated by micro-milling on repairing quality of damaged KH2PO4 crystal

PubMed Central

Chen, Ming-Jun; Cheng, Jian; Yuan, Xiao-Dong; Liao, Wei; Wang, Hai-Jun; Wang, Jing-He; Xiao, Yong; Li, Ming-Quan

2015-01-01

Repairing initial slight damage site into stable structures by engineering techniques is the leading strategy to mitigate the damage growth on large-size components used in laser-driven fusion facilities. For KH2PO4 crystals, serving as frequency converter and optoelectronic switch-Pockels cell, micro-milling has been proven the most promising method to fabricate these stable structures. However, tool marks inside repairing pit would be unavoidably introduced due to the wearing of milling cutter in actual repairing process. Here we quantitatively investigate the effect of tool marks on repairing quality of damaged crystal components by simulating its induced light intensification and testing the laser-induced damage threshold. We found that due to the formation of focusing hot spots and interference ripples, the light intensity is strongly enhanced with the presence of tool marks, especially for those on rear surfaces. Besides, the negative effect of tool marks is mark density dependent and multiple tool marks would aggravate the light intensification. Laser damage tests verified the role of tool marks as weak points, reducing the repairing quality. This work offers new criterion to comprehensively evaluate the quality of repaired optical surfaces to alleviate the bottleneck issue of low laser damage threshold for optical components in laser-driven fusion facilities. PMID:26399624

A unique mitigator sequence determines the species specificity of the major late promoter in adenovirus type 12 DNA.

PubMed Central

Zock, C; Iselt, A; Doerfler, W

1993-01-01

Human adenovirus type 12 (Ad12) cannot replicate in hamster cells, whereas human cells are permissive for Ad12. Ad12 DNA replication and late-gene and virus-associated RNA expression are blocked in hamster cells. Early Ad12 genes are transcribed, and the viral DNA can be integrated into the host genome. Ad12 DNA replication and late-gene transcription can be complemented in hamster cells by E1 functions of Ad2 or Ad5, for which hamster cells are fully permissive (for a review, see W. Doerfler, Adv. Virus Res. 39:89-128, 1991). We have previously demonstrated that a 33-nucleotide mitigator sequence, which is located in the downstream region of the major late promoter (MLP) of Ad12 DNA, is responsible for the inactivity of the Ad12 MLP in hamster cells (C. Zock and W. Doerfler, EMBO J. 9:1615-1623, 1990). A similar negative regulator has not been found in the MLP of Ad2 DNA. We have now studied the mechanism of action of this mitigator element. The results of nuclear run-on experiments document the absence of MLP transcripts in the nuclei of Ad12-infected BHK21 hamster cells. Surprisingly, the mitigator element cannot elicit its function in in vitro transcription experiments with nuclear extracts from both hamster BHK21 and human HeLa cells. Intact nuclear topology and/or tightly bound nuclear elements that cannot be eluted in nuclear extracts are somehow required for recognition of the Ad12 mitigator. Electrophoretic mobility shift assays have not revealed significant differences in the binding of proteins from human HeLa or hamster BHK21 cells to the mitigator sequence in the MLP of Ad12 DNA or to the corresponding sequence in Ad2 DNA. We have converted the sequence of the mitigator in the MLP of Ad12 DNA to the equivalent sequence in the MLP of Ad2 DNA by site-directed mutagenesis. This construct was not active in hamster cells. When the Ad12 mitigator, on the other hand, was inserted into the Ad2 MLP, the latter's function in hamster cells was not compromised. Deletions in the 5' upstream region of the Ad12 MLP have provided evidence for the existence of additional sequences that codetermine the deficiency of the Ad12 MLP in hamster cells. The amphifunctional YY1 protein from HeLa cells can bind specifically to the mitigator and to upstream elements of the MLP of Ad12 DNA.(ABSTRACT TRUNCATED AT 400 WORDS) Images PMID:8419643

The effect of bovine lactoferrin and lactoferricin B on the ability of feline calicivirus (a norovirus surrogate) and poliovirus to infect cell cultures.

PubMed

McCann, K B; Lee, A; Wan, J; Roginski, H; Coventry, M J

2003-01-01

To characterize the effect of bovine lactoferrin and lactoferricin B against feline calicivirus (FCV), a norovirus surrogate and poliovirus (PV), as models for enteric viruses. Crandell-Reese feline kidney (CRFK) cells were used for the propagation of FCV and monkey embryo kidney (MEK) cells for PV. The assays included visual assessment of cell lines for cytopathic effects and determination of the percentage cell death using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium] dye reduction assay. Incubation of bovine lactoferrin with CRFK cells either prior to or together with FCV inoculation substantially reduced FCV infection. In contrast, the interference of lactoferrin with the infection of cells with PV was demonstrated only when lactoferrin was present with cell lines and virus for the entire assay period. Using indirect immunofluorescence, lactoferrin was detected on the surface of both CRFK and MEK cells, suggesting that the interference of viral infection may be attributed to lactoferrin binding to the surfaces of susceptible cells, thereby preventing the attachment of the virus particles. Lactoferricin B, a cationic antimicrobial peptide derived from the N-terminal domain of bovine lactoferrin, reduced FCV but not PV infection. Lactoferrin was shown to interfere with the infection of cells for both FCV and PV. However, lactoferricin B showed no interference of infection with PV and interference with infection for FCV required the presence of lactoferricin B together with the cell line and virus. An in vitro basis is provided for the effects of bovine lactoferrin and lactoferricin B in moderating food-borne infections of enteric viruses.

Fuzzy-logic based Q-Learning interference management algorithms in two-tier networks

NASA Astrophysics Data System (ADS)

Xu, Qiang; Xu, Zezhong; Li, Li; Zheng, Yan

2017-10-01

Unloading from macrocell network and enhancing coverage can be realized by deploying femtocells in the indoor scenario. However, the system performance of the two-tier network could be impaired by the co-tier and cross-tier interference. In this paper, a distributed resource allocation scheme is studied when each femtocell base station is self-governed and the resource cannot be assigned centrally through the gateway. A novel Q-Learning interference management scheme is proposed, that is divided into cooperative and independent part. In the cooperative algorithm, the interference information is exchanged between the cell-edge users which are classified by the fuzzy logic in the same cell. Meanwhile, we allocate the orthogonal subchannels to the high-rate cell-edge users to disperse the interference power when the data rate requirement is satisfied. The resource is assigned directly according to the minimum power principle in the independent algorithm. Simulation results are provided to demonstrate the significant performance improvements in terms of the average data rate, interference power and energy efficiency over the cutting-edge resource allocation algorithms.

Recent Developments in Space Debris Mitigation Policy and Practices

NASA Technical Reports Server (NTRS)

Johnson, Nicholas L.

2006-01-01

In recent years, emphasis has shifted from national efforts to control the space debris population to international ones. Here, too, great progress has been made, most notably by the Inter-Agency Space Debris Coordination Committee (IADC) and the Committee on the Peaceful Uses of Outer Space (COPUOS) of the United Nations. Today, a firm international consensus is rapidly building on the principal space debris mitigation measures. The IADC is an association of the space agencies of ten countries (China, France, Germany, India, Italy, Japan, Russia, Ukraine, the United Kingdom, and the United States) and the European Space Agency, representing 17 countries of which four (France, Germany, Italy, and the United Kingdom) are also full IADC members. At the 17th meeting of the IADC in October 1999, a new Action Item (AI 17.2) was adopted to develop a set of consensus space debris mitigation guidelines. The purpose of the activity was to identify the most valuable space debris mitigation measures and to reach an international agreement on common directives. The IADC Space Debris Mitigation Guidelines (www.iadc-online.org/index.cgi?item=docs_pub) were formally adopted in October 2002 during the Second World Space Congress in Houston, Texas. Two years later a companion document, entitled Support to the IADC Space Debris Mitigation Guidelines, was completed to provide background and clarification for the guidelines.

Performance Analysis of a Hardware Implemented Complex Signal Kurtosis Radio-Frequency Interference Detector

NASA Technical Reports Server (NTRS)

Schoenwald, Adam J.; Bradley, Damon C.; Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Wong, Mark

2016-01-01

Radio-frequency interference (RFI) is a known problem for passive remote sensing as evidenced in the L-band radiometers SMOS, Aquarius and more recently, SMAP. Various algorithms have been developed and implemented on SMAP to improve science measurements. This was achieved by the use of a digital microwave radiometer. RFI mitigation becomes more challenging for microwave radiometers operating at higher frequencies in shared allocations. At higher frequencies larger bandwidths are also desirable for lower measurement noise further adding to processing challenges. This work focuses on finding improved RFI mitigation techniques that will be effective at additional frequencies and at higher bandwidths. To aid the development and testing of applicable detection and mitigation techniques, a wide-band RFI algorithm testing environment has been developed using the Reconfigurable Open Architecture Computing Hardware System (ROACH) built by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) Group. The testing environment also consists of various test equipment used to reproduce typical signals that a radiometer may see including those with and without RFI. The testing environment permits quick evaluations of RFI mitigation algorithms as well as show that they are implementable in hardware. The algorithm implemented is a complex signal kurtosis detector which was modeled and simulated. The complex signal kurtosis detector showed improved performance over the real kurtosis detector under certain conditions. The real kurtosis is implemented on SMAP at 24 MHz bandwidth. The complex signal kurtosis algorithm was then implemented in hardware at 200 MHz bandwidth using the ROACH. In this work, performance of the complex signal kurtosis and the real signal kurtosis are compared. Performance evaluations and comparisons in both simulation as well as experimental hardware implementations were done with the use of receiver operating characteristic (ROC) curves. The complex kurtosis algorithm has the potential to reduce data rate due to onboard processing in addition to improving RFI detection performance.

Joint digital signal processing for superchannel coherent optical communication systems.

PubMed

Liu, Cheng; Pan, Jie; Detwiler, Thomas; Stark, Andrew; Hsueh, Yu-Ting; Chang, Gee-Kung; Ralph, Stephen E

2013-04-08

Ultra-high-speed optical communication systems which can support ≥ 1Tb/s per channel transmission will soon be required to meet the increasing capacity demand. However, 1Tb/s over a single carrier requires either or both a high-level modulation format (i.e. 1024QAM) and a high baud rate. Alternatively, grouping a number of tightly spaced "sub-carriers" to form a terabit superchannel increases channel capacity while minimizing the need for high-level modulation formats and high baud rate, which may allow existing formats, baud rate and components to be exploited. In ideal Nyquist-WDM superchannel systems, optical subcarriers with rectangular spectra are tightly packed at a channel spacing equal to the baud rate, thus achieving the Nyquist bandwidth limit. However, in practical Nyquist-WDM systems, precise electrical or optical control of channel spectra is required to avoid strong inter-channel interference (ICI). Here, we propose and demonstrate a new "super receiver" architecture for practical Nyquist-WDM systems, which jointly detects and demodulates multiple channels simultaneously and mitigates the penalties associated with the limitations of generating ideal Nyquist-WDM spectra. Our receiver-side solution relaxes the filter requirements imposed on the transmitter. Two joint DSP algorithms are developed for linear ICI cancellation and joint carrier-phase recovery. Improved system performance is observed with both experimental and simulation data. Performance analysis under different system configurations is conducted to demonstrate the feasibility and robustness of the proposed joint DSP algorithms.

Capacity and Delay Spread in Multilayer Diffusion-Based Molecular Communication (DBMC) Channel.

PubMed

Md Mustam, Saizalmursidi; Syed-Yusof, Sharifah K; Zubair, Suleiman

2016-10-01

In nanoscale communication, diffusion-based molecular communication (DBMC) in which information is encoded into molecule patterns by a transmitter nanomachine, has emerged as a promising communication system, particularly for biomedical and healthcare applications. Although, numerous studies have been conducted to evaluate and analyze DBMC systems, investigation on DBMC system through a multilayer channel has received less attention. The aims of this paper are to formulate channel characteristics and to evaluate the performance of multilayer DBMC channel in terms of delay spread and capacity. In this paper, the propagation of molecules over an n- layer channel is assumed to follow the Brownian motion and subjected to Fick's law of diffusion. Fourier transform is used to convert time to frequency domain functions. Besides, the multilayer channel is considered as a linear and deterministic channel. For the performance evaluation, the air-water-blood plasma medium representing the simplified multilayer diffusion model in the respiratory system was chosen. It was found that a high channel capacity can be achieved with wide transmission bandwidth, short transmission distance, and high averaged transmitted power. In addition, the findings showed that channel delay spread increases as both the transmission distance, and the pulse duration increased. By setting the symbol duration greater than the pulse duration or delay spread, an inter-symbol interference problem due to previous molecules transmission can be mitigated. These findings can be used as a guide in the development and fabrication of future artificial nanocommunication and nanonetworks systems involving multilayer transmission medium.

Articulatory settings of French-English bilingual speakers

NASA Astrophysics Data System (ADS)

Wilson, Ian

2005-04-01

The idea of a language-specific articulatory setting (AS), an underlying posture of the articulators during speech, has existed for centuries [Laver, Historiogr. Ling. 5 (1978)], but until recently it had eluded direct measurement. In an analysis of x-ray movies of French and English monolingual speakers, Gick et al. [Phonetica (in press)] link AS to inter-speech posture, allowing measurement of AS without interference from segmental targets during speech, and they give quantitative evidence showing AS to be language-specific. In the present study, ultrasound and Optotrak are used to investigate whether bilingual English-French speakers have two ASs, and whether this varies depending on the mode (monolingual or bilingual) these speakers are in. Specifically, for inter-speech posture of the lips, lip aperture and protrusion are measured using Optotrak. For inter-speech posture of the tongue, tongue root retraction, tongue body and tongue tip height are measured using optically-corrected ultrasound. Segmental context is balanced across the two languages ensuring that the sets of sounds before and after an inter-speech posture are consistent across languages. By testing bilingual speakers, vocal tract morphology across languages is controlled for. Results have implications for L2 acquisition, specifically the teaching and acquisition of pronunciation.

External Magnetic Field Reduction Techniques for the Advanced Stirling Radioisotope Generator

NASA Technical Reports Server (NTRS)

Niedra, Janis M.; Geng, Steven M.

2013-01-01

Linear alternators coupled to high efficiency Stirling engines are strong candidates for thermal-to-electric power conversion in space. However, the magnetic field emissions, both AC and DC, of these permanent magnet excited alternators can interfere with sensitive instrumentation onboard a spacecraft. Effective methods to mitigate the AC and DC electromagnetic interference (EMI) from solenoidal type linear alternators (like that used in the Advanced Stirling Convertor) have been developed for potential use in the Advanced Stirling Radioisotope Generator. The methods developed avoid the complexity and extra mass inherent in data extraction from multiple sensors or the use of shielding. This paper discusses these methods, and also provides experimental data obtained during breadboard testing of both AC and DC external magnetic field devices.

Fiber-optic polarization diversity detection for rotary probe optical coherence tomography.

PubMed

Lee, Anthony M D; Pahlevaninezhad, Hamid; Yang, Victor X D; Lam, Stephen; MacAulay, Calum; Lane, Pierre

2014-06-15

We report a polarization diversity detection scheme for optical coherence tomography with a new, custom, miniaturized fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the X and Y OCT polarization channels prior to interference and the PM fiber outputs ensure defined X and Y axes after interference. Advantages for this scheme include easier alignment, lower cost, and easier miniaturization compared to designs with free-space bulk optical components. We demonstrate the utility of the detection system to mitigate the effects of rapidly changing polarization states when imaging with rotating fiber optic probes in Intralipid suspension and during in vivo imaging of human airways.

Identifying Cross-Disciplinary Interactions to Assess and Promote Functional Resilience in Flight Crews During Exploration Missions

NASA Technical Reports Server (NTRS)

Shelhamer, M.; Mindock, J.; Lumpkins, S.

2015-01-01

NASA supports research to mitigate risks to health and performance on extended missions. Typically these risks are investigated independently. In reality, physiological systems are tightly coupled, and related to psychological and inter-individual factors (team cohesion, conflict). We draw on ideas from network theory to assess these interactions and better design a research framework to address them.

The Implementation of the Full Service School Reform Model and Its Impact on Middle School Climate and Student Achievement: An Investigative Study

ERIC Educational Resources Information Center

Johnson, Joseph Hamilton

2012-01-01

The Full Service Schools (FSS) reform model is an inter-agency collaboration between the District of Columbia Public Schools (DCPS), Choices, Inc., Insights Education Group and the DC Department of Mental Health. This comprehensive school reform model is based in the Response to Intervention paradigm and is designed to mitigate student academic…

Military Handbook: Management and Design Guidance Electromagnetic Radiation Hardness for Air Launched Ordnance Systems

DTIC Science & Technology

1981-01-15

system is attacted to the delivery aircraft until it Impacto a target, it is exposed to electromagnetic radiation from emitters aboard the delivery...homogeneous, isotropic, ambient medium may be a lossy dielectric. Antenna computations include cur- rent distribution, input impedance, radiation...permissible ambient interference level in the system, and when determining the expected signal-to-inter- ference ratio of the signal transmission circuits

Mechanisms of carbon nanotube-induced toxicity: Focus on oxidative stress

PubMed Central

Shvedova, Anna A.; Pietroiusti, Antonio; Fadeel, Bengt; Kagan, Valerian E.

2015-01-01

Nanotechnologies are emerging as highly promising technologies in many sectors in the society. However, the increasing use of engineered nanomaterials also raises concerns about inadvertent exposure to these materials and the potential for adverse effects on human health and the environment. Despite several years of intensive investigations, a common paradigm for the understanding of nanoparticle-induced toxicity remains to be firmly established. Here, the so-called oxidative stress paradigm is scrutinized. Does oxidative stress represent a secondary event resulting inevitably from disruption of biochemical processes and the demise of the cell, or a specific, non-random event that plays a role in the induction of cellular damage e.g. apoptosis? The answer to this question will have important ramifications for the development of strategies for mitigation of adverse effects of nanoparticles. Recent examples of global lipidomics studies of nanoparticle-induced tissue damage are discussed along with proteomics and transcriptomics approaches to achieve a comprehensive understanding of the complex and interrelated molecular changes in cells and tissues exposed to nanoparticles. We also discuss instances of non-oxidative stress-mediated cellular damage resulting from direct physical interference of nanomaterials with cellular structures. PMID:22513272

Performance Evaluation of Wearable Sensor Systems: A Case Study in Moderate-Scale Deployment in Hospital Environment.

PubMed

Sun, Wen; Ge, Yu; Zhang, Zhiqiang; Wong, Wai-Choong

2015-09-25

A wearable sensor system enables continuous and remote health monitoring and is widely considered as the next generation of healthcare technology. The performance, the packet error rate (PER) in particular, of a wearable sensor system may deteriorate due to a number of factors, particularly the interference from the other wearable sensor systems in the vicinity. We systematically evaluate the performance of the wearable sensor system in terms of PER in the presence of such interference in this paper. The factors that affect the performance of the wearable sensor system, such as density, traffic load, and transmission power in a realistic moderate-scale deployment case in hospital are all considered. Simulation results show that with 20% duty cycle, only 68.5% of data transmission can achieve the targeted reliability requirement (PER is less than 0.05) even in the off-peak period in hospital. We then suggest some interference mitigation schemes based on the performance evaluation results in the case study.

Over-the-air in-band full-duplex system with hybrid RF optical and baseband digital self-interference cancellation

NASA Astrophysics Data System (ADS)

Zhang, Yunhao; Li, Longsheng; Bi, Meihua; Xiao, Shilin

2017-12-01

In this paper, we propose a hybrid analog optical self-interference cancellation (OSIC) and baseband digital SIC (DSIC) system for over-the-air in-band full-duplex (IBFD) wireless communication. Analog OSIC system is based on optical delay line, electro-absorption modulation lasers (EMLs) and balanced photodetector (BPD), which has the properties of high adjusting precision and broad processing bandwidth. With the help of baseband DSIC, the cancellation depth limitation of OSIC can be mitigated so as to achieve deeper total SIC depth. Experimental results show about 20-dB depth by OSIC and 10-dB more depth by DSIC over 1GHz broad baseband, so that the signal of interest (SOI) overlapped by wideband self-interference (SI) signal is better recovered compared to the IBFD system with OSIC or DSIC only. The hybrid of OSIC and DSIC takes advantages of the merits of optical devices and digital processors to achieve deep cancellation depth over broad bandwidth.

Stage-dependency of apoptosis and the blood-testis barrier in the dogfish shark (Squalus acanthias): cadmium-induced changes as assessed by vital fluorescence techniques.

PubMed

McClusky, Leon M

2006-09-01

Naturally occurring heavy metals and synthetic compounds are potentially harmful for testicular function but evidence linking heavy metal exposure to reduced semen parameters is inconclusive. Elucidation of the exact stage at which the toxicant interferes with spermatogenesis is difficult because the various germ cell stages may have different sensitivities to any given toxicant, germ cell development is influenced by supporting testicular somatic cells and the presence of inter-Sertoli cell tight junctions create a blood-testis barrier, sequestering meiotic and postmeiotic germ cells in a special microenvironment. Sharks such as Squalus acanthias provide a suitable model for studying aspects of vertebrate spermatogenosis because of their unique features: spermatogenesis takes place within spermatocysts and relies mainly on Sertoli cells for somatic cell support; spermatocysts are linearly arranged in a maturational order across the diameter of the elongated testis; spermatocysts containing germ cells at different stages of development are topographically separated, resulting in visible zonation in testicular cross sections. We have used the vital dye acridine orange and a novel fluorescence staining technique to study this model to determine (1) the efficacy of these methods in assays of apoptosis and blood-testis barrier function, (2) the sensitivity of the various spermatogonial generations in Squalus to cadmium (as an illustrative spermatotoxicant) and (3) the way that cadmium might affect more mature spermatogenic stages and other physiological processes in the testis. Our results show that cadmium targets early spermatogenic stages, where it specifically activates a cell death program in susceptible (mature) spermatogonial clones, and negatively affects blood-testis barrier function. Since other parameters are relatively unaffected by cadmium, the effects of this toxicant on apoptosis are presumably process-specific and not attributable to general toxicity.

Interactions between the Space Station and the environment: A preliminary assessment of EMI

NASA Technical Reports Server (NTRS)

Murphy, G. B.; Garrett, Henry B.

1990-01-01

A review of the interactions between proposed Space Station systems/payloads and the environment that contribute to electromagnetic interference was performed. Seven prime sources of interference have been identified. These are: The Space Station power system; active experiments such as beam injection; ASTROMAG; ram and wake density gradients; pick up ions produced by vented or offgassed clouds; waves produced by current loops that include the plasma and structure; arcing from high voltage solar arrays (or possible ESD in polar orbit). This review indicates that: minimizing leakage current from the 20 kHz power system to the structure; keeping the surfaces of the Space Station structure, arrays, and radiators nonconducting; minimizing venting of payloads or systems to non-operational periods; careful placement of payloads sensitive to magnetic field perturbations or wake noise; and designing an operational timeline compatible with experiment requirement are the most effective means of minimizing the effects of this interference. High degrees of uncertainty exist in the estimates of magnitudes of gas emission induced EMI, radiation of 20 kHz and harmonics, ASTROMAG induced interference, and arc threshold/frequency of the solar array. These processes demand further attention so that mitigation efforts are properly calibrated.

Integrated Droplet-Based Microextraction with ESI-MS for Removal of Matrix Interference in Single-Cell Analysis.

PubMed

Zhang, Xiao-Chao; Wei, Zhen-Wei; Gong, Xiao-Yun; Si, Xing-Yu; Zhao, Yao-Yao; Yang, Cheng-Dui; Zhang, Si-Chun; Zhang, Xin-Rong

2016-04-29

Integrating droplet-based microfluidics with mass spectrometry is essential to high-throughput and multiple analysis of single cells. Nevertheless, matrix effects such as the interference of culture medium and intracellular components influence the sensitivity and the accuracy of results in single-cell analysis. To resolve this problem, we developed a method that integrated droplet-based microextraction with single-cell mass spectrometry. Specific extraction solvent was used to selectively obtain intracellular components of interest and remove interference of other components. Using this method, UDP-Glc-NAc, GSH, GSSG, AMP, ADP and ATP were successfully detected in single MCF-7 cells. We also applied the method to study the change of unicellular metabolites in the biological process of dysfunctional oxidative phosphorylation. The method could not only realize matrix-free, selective and sensitive detection of metabolites in single cells, but also have the capability for reliable and high-throughput single-cell analysis.

Polymorphism in liver-stage malaria vaccine candidate proteins: immune evasion and implications for vaccine design.

PubMed

Flanagan, Katie L; Wilson, Kirsty L; Plebanski, Magdalena

2016-01-01

The pre-erythrocytic stage of infection by malaria parasites represents a key target for vaccines that aim to eradicate malaria. Two important broad immune evasion strategies that can interfere with vaccine efficacy include the induction of dendritic cell (DC) dysfunction and regulatory T cells (Tregs) by blood-stage malaria parasites, leading to inefficient priming of T cells targeting liver-stage infections. The parasite also uses 'surgical strike' strategies, whereby polymorphism in pre-erythrocytic antigens can interfere with host immunity. Specifically, we review how even single amino acid changes in T cell epitopes can lead to loss of binding to major histocompatibility complex (MHC), lack of cross-reactivity, or antagonism and immune interference, where simultaneous or sequential stimulation with related variants of the same T cell epitope can cause T cell anergy or the conversion of effector to immunosuppressive T cell phenotypes.

Nitric oxide interferes with islet cell zinc homeostasis.

PubMed

Tartler, U; Kröncke, K D; Meyer, K L; Suschek, C V; Kolb-Bachofen, V

2000-12-01

Zinc is crucial for the biosynthesis, storage, and secretion of insulin in pancreatic islet cells. We have previously presented evidence that NO interferes with cellular Zn(2+) homeostasis and we therefore investigated the influence of chronic NO exposure on the labile islet cell Zn(2+) content. A strong fluorescence activity in a large islet cell subpopulation was found after staining with the Zn(2+)-specific fluorophore Zinquin. Culture for 24 h in the presence of nontoxic concentrations of the slow-releasing NO donor DETA/NO resulted in a significantly reduced Zn(2+)-dependent fluorescence. This appears to be islet specific as in endothelial cells DETA/NO exposure enhanced the Zn(2+)-dependent fluorescence activity in a concentration-dependent manner. These results suggest that NO interferes with cellular Zn(2+) homeostasis, which in islet cells is crucial for proper hormone delivery and thus special cell function. Copyright 2000 Academic Press.

An orientation-independent DIC microscope allows high resolution imaging of epithelial cell migration and wound healing in a cnidarian model.

PubMed

Malamy, J E; Shribak, M

2018-06-01

Epithelial cell dynamics can be difficult to study in intact animals or tissues. Here we use the medusa form of the hydrozoan Clytia hemisphaerica, which is covered with a monolayer of epithelial cells, to test the efficacy of an orientation-independent differential interference contrast microscope for in vivo imaging of wound healing. Orientation-independent differential interference contrast provides an unprecedented resolution phase image of epithelial cells closing a wound in a live, nontransgenic animal model. In particular, the orientation-independent differential interference contrast microscope equipped with a 40x/0.75NA objective lens and using the illumination light with wavelength 546 nm demonstrated a resolution of 460 nm. The repair of individual cells, the adhesion of cells to close a gap, and the concomitant contraction of these cells during closure is clearly visualized. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

Bis-anthracycline WP760 abrogates melanoma cell growth by transcription inhibition, p53 activation and IGF1R downregulation.

PubMed

Olbryt, Magdalena; Rusin, Aleksandra; Fokt, Izabela; Habryka, Anna; Tudrej, Patrycja; Student, Sebastian; Sochanik, Aleksander; Zieliński, Rafał; Priebe, Waldemar

2017-10-01

Anthracycline chemotherapeutics, e.g. doxorubicin and daunorubicin, are active against a broad spectrum of cancers. Their cytotoxicity is mainly attributed to DNA intercalation, interference with topoisomerase activity, and induction of double-stranded DNA breaks. Since modification of anthracyclines can profoundly affect their pharmacological properties we attempted to elucidate the mechanism of action, and identify possible molecular targets, of bis-anthracycline WP760 which previously demonstrated anti-melanoma activity at low nanomolar concentrations. We studied the effect of WP760 on several human melanoma cell lines derived from tumors in various development stages and having different genetic backgrounds. WP760 inhibited cell proliferation (IC 50  = 1-99 nM), impaired clonogenic cell survival (100 nM), and inhibited spheroid growth (≥300 nM). WP760 did not induce double-stranded DNA breaks but strongly inhibited global transcription. Moreover, WP760 caused nucleolar stress and led to activation of the p53 pathway. PCR array analysis showed that WP760 suppressed transcription of ten genes (ABCC1, MTOR, IGF1R, EGFR, GRB2, PRKCA, PRKCE, HDAC4, TXNRD1, AKT1) associated with, inter alia, cytoprotective mechanisms initiated in cancer cells during chemotherapy. Furthermore, WP760 downregulated IGF1R and upregulated PLK2 expression in most of the tested melanoma cell lines. These results suggest that WP760 exerts anti-melanoma activity by targeting global transcription and activation of the p53 pathway and could become suitable as an effective therapeutic agent.

Are anxious workers less productive workers? It depends on the quality of social exchange.

PubMed

McCarthy, Julie M; Trougakos, John P; Cheng, Bonnie Hayden

2016-02-01

In this article, we draw from Conservation of Resources Theory to advance and test a framework which predicts that emotional exhaustion plays an explanatory role underlying the relation between workplace anxiety and job performance. Further, we draw from social exchange theories to predict that leader-member exchange and coworker exchange will mitigate the harmful effects of anxiety on job performance. Findings across a 3-wave study of police officers supported our model. Emotional exhaustion mediated the link between workplace anxiety and job performance, over and above the effect of cognitive interference. Further, coworker exchange mitigated the positive relation between anxiety and emotional exhaustion, while leader-member exchange mitigated the negative relation between emotional exhaustion and job performance. This study elucidates the effects of workplace anxiety on resource depletion via emotional exhaustion and highlights the value of drawing on social resources to offset the potentially harmful effects of workplace anxiety on job performance. (c) 2016 APA, all rights reserved).

Martian Atmospheric Dust Mitigation for ISRU Intakes via Electrostatic Precipitation

NASA Technical Reports Server (NTRS)

Phillips, James R., III; Pollard, Jacob R. S.; Johansen, Michael R.; Mackey, Paul J.; Clements, J. Sid; Calle, Carlos I.

2016-01-01

The Mars 2020 and Mars Sample Return missions expected to fly to Mars within the next ten years will each include an In Situ Resource Utilization (ISRU) system. They convert carbon dioxide in the Martian atmosphere into consumable oxygen at 1% and 20% of the rate required by a full scale human exploration Mars mission, respectively. The ISRU systems will need to draw in the surrounding atmosphere at a rate of 110L/min and 550L/min, respectively, in order to meet their oxygen production goals. Over the duration of each respective mission, a total atmospheric dust mass of 4.86g and 243g will be drawn into each system, respectively. Ingestion of large quantities of dust may interfere with ISRU operations, so a dust mitigation device will be required. The atmospheric volume and dust mass flow rates above will be utilized to simulate Martian environmental conditions in a laboratory electrostatic precipitator being developed to provide active dust mitigation support for atmospheric ISRU systems such as these.

Nuclear Countermeasure Activity of TP508 Linked to Restoration of Endothelial Function and Acceleration of DNA Repair

PubMed Central

Olszewska-Pazdrak, Barbara; McVicar, Scott D.; Rayavara, Kempaiah; Moya, Stephanie M.; Kantara, Carla; Gammarano, Chris; Olszewska, Paulina; Fuller, Gerald M.; Sower, Laurie E.; Carney, Darrell H.

2016-01-01

There is increasing evidence that radiation-induced damage to endothelial cells and loss of endothelial function may contribute to both acute radiation syndromes and long-term effects of whole-body nuclear irradiation. Therefore, several drugs are being developed to mitigate the effects of nuclear radiation, most of these drugs will target and protect or regenerate leukocytes and platelets. Our laboratory has demonstrated that TP508, a 23-amino acid thrombin peptide, activates endothelial cells and stem cells to revascularize and regenerate tissues. We now show that TP508 can mitigate radiation-induced damage to endothelial cells in vitro and in vivo. Our in vitro results demonstrate that human endothelial cells irradiation attenuates nitric oxide (NO) signaling, disrupts tube formation and induces DNA double-strand breaks (DSB). TP508 treatment reverses radiation effects on NO signaling, restores tube formation and accelerates the repair of radiation-induced DSB. The radiation-mitigating effects of TP508 on endothelial cells were also seen in CD-1 mice where systemic injection of TP508 stimulated endothelial cell sprouting from aortic explants after 8 Gy irradiation. Systemic doses of TP508 that mitigated radiation-induced endothelial cell damage, also significantly increased survival of CD-1 mice when injected 24 h after 8.5 Gy exposure. These data suggest that increased survival observed with TP508 treatment may be due to its effects on vascular and microvascular endothelial cells. Our study supports the usage of a regenerative drug such as TP508 to activate endothelial cells as a countermeasure for mitigating the effects of nuclear radiation. PMID:27388041

LITE microscopy: Tilted light-sheet excitation of model organisms offers high resolution and low photobleaching

PubMed Central

Gerbich, Therese M.; Rana, Kishan; Suzuki, Aussie; Schaefer, Kristina N.; Heppert, Jennifer K.; Boothby, Thomas C.; Allbritton, Nancy L.; Gladfelter, Amy S.; Maddox, Amy S.

2018-01-01

Fluorescence microscopy is a powerful approach for studying subcellular dynamics at high spatiotemporal resolution; however, conventional fluorescence microscopy techniques are light-intensive and introduce unnecessary photodamage. Light-sheet fluorescence microscopy (LSFM) mitigates these problems by selectively illuminating the focal plane of the detection objective by using orthogonal excitation. Orthogonal excitation requires geometries that physically limit the detection objective numerical aperture (NA), thereby limiting both light-gathering efficiency (brightness) and native spatial resolution. We present a novel live-cell LSFM method, lateral interference tilted excitation (LITE), in which a tilted light sheet illuminates the detection objective focal plane without a sterically limiting illumination scheme. LITE is thus compatible with any detection objective, including oil immersion, without an upper NA limit. LITE combines the low photodamage of LSFM with high resolution, high brightness, and coverslip-based objectives. We demonstrate the utility of LITE for imaging animal, fungal, and plant model organisms over many hours at high spatiotemporal resolution. PMID:29490939

Rapid mitigation of carrier-induced degradation in commercial silicon solar cells

NASA Astrophysics Data System (ADS)

Hallam, Brett J.; Chan, Catherine E.; Chen, Ran; Wang, Sisi; Ji, Jingjia; Mai, Ly; Abbott, Malcolm D.; Payne, David N. R.; Kim, Moonyong; Chen, Daniel; Chong, CheeMun; Wenham, Stuart R.

2017-08-01

We report on the progress for the understanding of carrier-induced degradation (CID) in p-type mono and multi-crystalline silicon (mc-Si) solar cells, and methods of mitigation. Defect formation is a key aspect to mitigating CID. Illuminated annealing can be used for both mono and mc-Si solar cells to reduce CID. The latest results of an 8-s UNSW advanced hydrogenation process applied to industrial p-type Czochralski PERC solar cells are shown with average efficiency enhancements of 1.1% absolute from eight different solar cell manufacturers. Results from three new industrial CID mitigation tools are presented, reducing CID to 0.8-1.1% relative, compared to 4.2% relative on control cells. Similar advanced hydrogenation processes can also be applied to multi-crystalline silicon passivated emitter with rear local contact (PERC) cells, however to date, the processes take longer and are less effective. Modifications to the firing processes can also suppress CID in multi-crystalline cells during subsequent illumination. The most stable results are achieved with a multi-stage process consisting of a second firing process at a reduced firing temperature, followed by extended illuminated annealing.

Tuning time-frequency methods for the detection of metered HF speech

NASA Astrophysics Data System (ADS)

Nelson, Douglas J.; Smith, Lawrence H.

2002-12-01

Speech is metered if the stresses occur at a nearly regular rate. Metered speech is common in poetry, and it can occur naturally in speech, if the speaker is spelling a word or reciting words or numbers from a list. In radio communications, the CQ request, call sign and other codes are frequently metered. In tactical communications and air traffic control, location, heading and identification codes may be metered. Moreover metering may be expected to survive even in HF communications, which are corrupted by noise, interference and mistuning. For this environment, speech recognition and conventional machine-based methods are not effective. We describe Time-Frequency methods which have been adapted successfully to the problem of mitigation of HF signal conditions and detection of metered speech. These methods are based on modeled time and frequency correlation properties of nearly harmonic functions. We derive these properties and demonstrate a performance gain over conventional correlation and spectral methods. Finally, in addressing the problem of HF single sideband (SSB) communications, the problems of carrier mistuning, interfering signals, such as manual Morse, and fast automatic gain control (AGC) must be addressed. We demonstrate simple methods which may be used to blindly mitigate mistuning and narrowband interference, and effectively invert the fast automatic gain function.

Circular SAR GMTI

NASA Astrophysics Data System (ADS)

Page, Douglas; Owirka, Gregory; Nichols, Howard; Scarborough, Steven

2014-06-01

We describe techniques for improving ground moving target indication (GMTI) performance in multi-channel synthetic aperture radar (SAR) systems. Our approach employs a combination of moving reference processing (MRP) to compensate for defocus of moving target SAR responses and space-time adaptive processing (STAP) to mitigate the effects of strong clutter interference. Using simulated moving target and clutter returns, we demonstrate focusing of the target return using MRP, and discuss the effect of MRP on the clutter response. We also describe formation of adaptive degrees of freedom (DOFs) for STAP filtering of MRP processed data. For the simulated moving target in clutter example, we demonstrate improvement in the signal to interference plus noise (SINR) loss compared to more standard algorithm configurations. In addition to MRP and STAP, the use of tracker feedback, false alarm mitigation, and parameter estimation techniques are also described. A change detection approach for reducing false alarms from clutter discretes is outlined, and processing of a measured data coherent processing interval (CPI) from a continuously orbiting platform is described. The results demonstrate detection and geolocation of a high-value target under track. The endoclutter target is not clearly visible in single-channel SAR chips centered on the GMTI track prediction. Detections are compared to truth data before and after geolocation using measured angle of arrival (AOA).

In vitro development and cytological quality of inter-species (porcine→bovine) cloned embryos are affected by trichostatin A-dependent epigenomic modulation of adult mesenchymal stem cells.

PubMed

Opiela, J; Samiec, M; Romanek, J

2017-07-15

Artificial epigenomic modulation of in vitro cultured mesenchymal stem cells (MSCs) by applying a non-selective HDAC inhibitor, termed TSA, can facilitate more epigenetic reprogramming of transcriptional activity of the somatic cell-descended nuclear genome in NT pig embryos. The results of the present investigation showed that TSA-dependent epigenomic modulation of nuclear donor MSCs highly affects both the in vitro developmental capability and the cytological quality of inter-species (porcine→bovine) cloned embryos. The developmental competences to reach the blastocyst stage among hybrid (porcine→bovine) nuclear-transferred embryos that had been reconstructed with bovine ooplasts and epigenetically modulated porcine MSCs were maintained at a relatively high level. These competences were higher than those noted in studies by other authors, but they were still decreased compared to those of intra-species (porcine) cloned embryos that had been reconstituted with porcine ooplasts and either the cell nuclei of epigenetically transformed MSCs or the cell nuclei of epigenetically non-transformed MSCs. In conclusion, MSCs undergoing TSA-dependent epigenetic transformation were used for the first time as a source of nuclear donor cells not only for inter-species somatic cell cloning in pigs but also for inter-species somatic cell cloning in other livestock species. Moreover, as a result of the current research, efficient sequential physicochemical activation of inter-species nuclear-transferred clonal cybrids derived from bovine ooplasm and porcine MSC nuclei was developed. Copyright © 2017 Elsevier Inc. All rights reserved.

Bangladesh arsenic mitigation programs: lessons from the past

PubMed Central

Milton, Abul Hasnat; Hore, Samar Kumar; Hossain, Mohammad Zahid; Rahman, Mahfuzar

2012-01-01

Ensuring access to safe drinking water by 2015 is a global commitment by the Millennium Development Goals (MDGs). In Bangladesh, significant achievements in providing safe water were made earlier by nationwide tubewell-installation programme. This achievement was overshadowed in 1993 by the presence of arsenic in underground water. A total of 6 million tubewells have been tested for arsenic since then, the results of which warranted immediate mitigation. Mitigation measures included tubewell testing and replacing; usage of deeper wells; surface water preservation and treatment; use of sanitary dug wells, river sand and pond sand filters; rainwater collection and storage; household-scale and large-scale arsenic filtrations; and rural pipeline water supply installation. Shallow tubewell installation was discouraged. Efforts have been made to increase people's awareness. This paper describes the lessons learned about mitigation efforts by the authors from experience of arsenic-related work. In spite of national mitigation plans and efforts, a few challenges still persist: inadequate coordination between stakeholders, differences in inter-sectoral attitudes, inadequate research to identify region-specific, suitable safe water options, poor quality of works by various implementing agencies, and inadequate dissemination of the knowledge and experiences to the people by those organizations. Issues such as long-time adaptation using ground water, poor surface water quality including bad smell and turbidity, and refusal to using neighbor's water have delayed mitigation measures so far. Region-specific mitigation water supply policy led by the health sector could be adopted with multisectoral involvement and responsibility. Large-scale piped water supply could be arranged through Public Private Partnerships (PPP) in new national approach. PMID:22558005

Bangladesh arsenic mitigation programs: lessons from the past.

PubMed

Milton, Abul Hasnat; Hore, Samar Kumar; Hossain, Mohammad Zahid; Rahman, Mahfuzar

2012-01-01

Ensuring access to safe drinking water by 2015 is a global commitment by the Millennium Development Goals (MDGs). In Bangladesh, significant achievements in providing safe water were made earlier by nationwide tubewell-installation programme. This achievement was overshadowed in 1993 by the presence of arsenic in underground water. A total of 6 million tubewells have been tested for arsenic since then, the results of which warranted immediate mitigation. Mitigation measures included tubewell testing and replacing; usage of deeper wells; surface water preservation and treatment; use of sanitary dug wells, river sand and pond sand filters; rainwater collection and storage; household-scale and large-scale arsenic filtrations; and rural pipeline water supply installation. Shallow tubewell installation was discouraged. Efforts have been made to increase people's awareness. This paper describes the lessons learned about mitigation efforts by the authors from experience of arsenic-related work. In spite of national mitigation plans and efforts, a few challenges still persist: inadequate coordination between stakeholders, differences in inter-sectoral attitudes, inadequate research to identify region-specific, suitable safe water options, poor quality of works by various implementing agencies, and inadequate dissemination of the knowledge and experiences to the people by those organizations. Issues such as long-time adaptation using ground water, poor surface water quality including bad smell and turbidity, and refusal to using neighbor's water have delayed mitigation measures so far. Region-specific mitigation water supply policy led by the health sector could be adopted with multisectoral involvement and responsibility. Large-scale piped water supply could be arranged through Public Private Partnerships (PPP) in new national approach.

Between-Trial Forgetting Due to Interference and Time in Motor Adaptation.

PubMed

Kim, Sungshin; Oh, Youngmin; Schweighofer, Nicolas

2015-01-01

Learning a motor task with temporally spaced presentations or with other tasks intermixed between presentations reduces performance during training, but can enhance retention post training. These two effects are known as the spacing and contextual interference effect, respectively. Here, we aimed at testing a unifying hypothesis of the spacing and contextual interference effects in visuomotor adaptation, according to which forgetting between trials due to either spaced presentations or interference by another task will promote between-trial forgetting, which will depress performance during acquisition, but will promote retention. We first performed an experiment with three visuomotor adaptation conditions: a short inter-trial-interval (ITI) condition (SHORT-ITI); a long ITI condition (LONG-ITI); and an alternating condition with two alternated opposite tasks (ALT), with the same single-task ITI as in LONG-ITI. In the SHORT-ITI condition, there was fastest increase in performance during training and largest immediate forgetting in the retention tests. In contrast, in the ALT condition, there was slowest increase in performance during training and little immediate forgetting in the retention tests. Compared to these two conditions, in the LONG-ITI, we found intermediate increase in performance during training and intermediate immediate forgetting. To account for these results, we fitted to the data six possible adaptation models with one or two time scales, and with interference in the fast, or in the slow, or in both time scales. Model comparison confirmed that two time scales and some degree of interferences in either time scale are needed to account for our experimental results. In summary, our results suggest that retention following adaptation is modulated by the degree of between-trial forgetting, which is due to time-based decay in single adaptation task and interferences in multiple adaptation tasks.

Cell volume and plasma membrane osmotic water permeability in epithelial cell layers measured by interferometry.

PubMed Central

Farinas, J; Verkman, A S

1996-01-01

The development of strategies to measure plasma membrane osmotic water permeability (Pf) in epithelial cells has been motivated by the identification of a family of molecular water channels. A general approach utilizing interferometry to measure cell shape and volume was developed and applied to measure Pf in cell layers. The method is based on the cell volume dependence of optical path length (OPL) for a light beam passing through the cell. The small changes in OPL were measured by interferometry. A mathematical model was developed to relate the interference signal to cell volume changes for cells of arbitrary shape and size. To validate the model, a Mach-Zehnder interference microscope was used to image OPL in an Madin Darby Canine Kidney (MDCK) cell layer and to reconstruct the three-dimensional cell shape (OPL resolution < lambda/25). As predicted by the model, a doubling of cell volume resulted in a change in OPL that was proportional to the difference in refractive indices between water and the extracellular medium. The time course of relative cell volume in response to an osmotic gradient was computed from serial interference images. To measure cell volume without microscopy and image analysis, a Mach-Zehnder interferometer was constructed in which one of two interfering laser beams passed through a flow chamber containing the cell layer. The interference signal in response to an osmotic gradient was analyzed to quantify the time course of relative cell volume. The calculated MDCK cell plasma membrane Pf of 6.1 x 10(-4) cm/s at 24 degrees C agreed with that obtained by interference microscopy and by a total internal reflection fluorescence method. Interferometry was also applied to measure the apical plasma membrane water permeability of intact toad urinary bladder; Pf increased fivefold after forskolin stimulation to 0.04 cm/s at 23 degrees C. These results establish and validate the application of interferometry to quantify cell volume and osmotic water permeability in cell layers. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 6 PMID:8968620

Monte Carlo study of x-ray cross talk in a variable resolution x-ray detector

NASA Astrophysics Data System (ADS)

Melnyk, Roman; DiBianca, Frank A.

2003-06-01

A variable resolution x-ray (VRX) detector provides a great increase in the spatial resolution of a CT scanner. An important factor that limits the spatial resolution of the detector is x-ray cross-talk. A theoretical study of the x-ray cross-talk is presented in this paper. In the study, two types of the x-ray cross-talk were considered: inter-cell and inter-arm cross-talk. Both types of the x-ray cross-talk were simulated, using the Monte Carlo method, as functions of the detector field of view (FOV). The simulation was repeated for lead and tungsten separators between detector cells. The inter-cell x-ray cross-talk was maximum at the 34-36 cm FOV, but it was low at small and the maximum FOVs. The inter-arm x-ray cross-talk was high at small and medium FOVs, but it was greatly reduced when variable width collimators were placed on the front surfaces of the detector. The inter-cell, but not inter-arm, x-ray cross-talk was lower for tungsten than for lead separators. From the results, x-ray cross-talk in a VRX detector can be minimized by imaging all objects between 24 cm and 40 cm in diameter with the 40 cm FOV, using tungsten separators, and placing variable width collimators in front of the detector.

Nonlinear regional warming with increasing CO2 concentrations

NASA Astrophysics Data System (ADS)

Good, Peter; Lowe, Jason A.; Andrews, Timothy; Wiltshire, Andrew; Chadwick, Robin; Ridley, Jeff K.; Menary, Matthew B.; Bouttes, Nathaelle; Dufresne, Jean Louis; Gregory, Jonathan M.; Schaller, Nathalie; Shiogama, Hideo

2015-02-01

When considering adaptation measures and global climate mitigation goals, stakeholders need regional-scale climate projections, including the range of plausible warming rates. To assist these stakeholders, it is important to understand whether some locations may see disproportionately high or low warming from additional forcing above targets such as 2 K (ref. ). There is a need to narrow uncertainty in this nonlinear warming, which requires understanding how climate changes as forcings increase from medium to high levels. However, quantifying and understanding regional nonlinear processes is challenging. Here we show that regional-scale warming can be strongly superlinear to successive CO2 doublings, using five different climate models. Ensemble-mean warming is superlinear over most land locations. Further, the inter-model spread tends to be amplified at higher forcing levels, as nonlinearities grow--especially when considering changes per kelvin of global warming. Regional nonlinearities in surface warming arise from nonlinearities in global-mean radiative balance, the Atlantic meridional overturning circulation, surface snow/ice cover and evapotranspiration. For robust adaptation and mitigation advice, therefore, potentially avoidable climate change (the difference between business-as-usual and mitigation scenarios) and unavoidable climate change (change under strong mitigation scenarios) may need different analysis methods.

Proposed FY13 LRIR: Shock-Mitigating Multilayered Mechanical Metamaterials (SM5)

DTIC Science & Technology

2012-08-02

DoD SMART Scholarship for Service Program Awareness Info Sharing Co-Funded Inter- locked 4Approved for Public Release; Distribution Unlimited (PA...Materials Modeling • Rate-dependent • Temperature-dependent • Complex properties Theoretical Mechanics • Dispersion • Wave modes/ polarization ...Dick (Rice) • Wavelet SEM in Plates, PI: Ratan Jha (Clarkson) – Soliton -Based Artificial Nervous System • PI’s: “JK” Yang (USC), Amanda Schrand

The relevance of dietary sodium in hemodialysis

PubMed Central

Mc Causland, Finnian R.; Waikar, Sushrut S.; Brunelli, Steven M.

2013-01-01

Since the earliest days of hemodialysis, dietary sodium restriction has been recommended as a therapeutic means to mitigate problems of extracellular volume overload, hypertension and inter-dialytic weight gain. Recently, there has been a proliferation of human subjects' research examining the potential effects of dietary sodium curtailment. Herein we examine the available evidence with respect to the effects of dietary sodium restriction on clinically relevant endpoints among hemodialysis patients. PMID:23129821

47 CFR 25.213 - Inter-Service coordination requirements for the 1.6/2.4 GHz Mobile-Satellite Service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... radio astronomy service in the 1610.6-1613.8 MHz band against interference from 1.6/2.4 GHz Mobile... System. (i) In the band 1610.6-1613.8 MHz, within a 160 km radius of the following radio astronomy sites... attenuated so that the power flux density it produces in the 1610.6-1613.8 MHz band at any radio astronomy...

47 CFR 25.213 - Inter-Service coordination requirements for the 1.6/2.4 GHz Mobile-Satellite Service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... radio astronomy service in the 1610.6-1613.8 MHz band against interference from 1.6/2.4 GHz Mobile... System. (i) In the band 1610.6-1613.8 MHz, within a 160 km radius of the following radio astronomy sites... attenuated so that the power flux density it produces in the 1610.6-1613.8 MHz band at any radio astronomy...

Technical Digest of the 1998 Summer Topical Meeting on Organic Optics and Optoelectronics

DTIC Science & Technology

1998-07-01

substantially larger voltages (~2x), however, signal distortion and inter- symbol interference due to multiple RF reflections limit their...technology as data page composers. Texas Instrument’s DMD 0-7803-4953-9/98$10.00©1998 IEEE system has already been used in this capacity in several... lithography for fabricating and integrating the heads and sliders. The application of MEMS components and micromachined optical bench packaging techniques

LASER BIOLOGY: Peculiarities of studying an isolated neuron by the method of laser interference microscopy

NASA Astrophysics Data System (ADS)

Yusipovich, Alexander I.; Novikov, Sergey M.; Kazakova, Tatiana A.; Erokhova, Liudmila A.; Brazhe, Nadezda A.; Lazarev, Grigory L.; Maksimov, Georgy V.

2006-09-01

Actual aspects of using a new method of laser interference microscopy (LIM) for studying nerve cells are discussed. The peculiarities of the LIM display of neurons are demonstrated by the example of isolated neurons of a pond snail Lymnaea stagnalis. A comparative analysis of the images of the cell and subcellular structures of a neuron obtained by the methods of interference microscopy, optical transmission microscopy, and confocal microscopy is performed. Various aspects of the application of LIM for studying the lateral dimensions and internal structure of the cytoplasm and organelles of a neuron in cytology and cell physiology are discussed.

Nanoparticle growth and surface chemistry changes in cell-conditioned culture medium.

PubMed

Kendall, Michaela; Hodges, Nikolas J; Whitwell, Harry; Tyrrell, Jess; Cangul, Hakan

2015-02-05

When biomolecules attach to engineered nanoparticle (ENP) surfaces, they confer the particles with a new biological identity. Physical format may also radically alter, changing ENP stability and agglomeration state within seconds. In order to measure which biomolecules are associated with early ENP growth, we studied ENPs in conditioned medium from A549 cell culture, using dynamic light scattering (DLS) and linear trap quadrupole electron transfer dissociation mass spectrometry. Two types of 100 nm polystyrene particles (one uncoated and one with an amine functionalized surface) were used to measure the influence of surface type. In identically prepared conditioned medium, agglomeration was visible in all samples after 1 h, but was variable, indicating inter-sample variability in secretion rates and extracellular medium conditions. In samples conditioned for 1 h or more, ENP agglomeration rates varied significantly. Agglomerate size measured by DLS was well correlated with surface sequestered peptide number for uncoated but not for amine coated polystyrene ENPs. Amine-coated ENPs grew much faster and into larger agglomerates associated with fewer sequestered peptides, but including significant sequestered lactose dehydrogenase. We conclude that interference with extracellular peptide balance and oxidoreductase activity via sequestration is worthy of further study, as increased oxidative stress via this new mechanism may be important for cell toxicity. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The effects of a single bout of exercise on motor memory interference in the trained and untrained hemisphere.

PubMed

Lauber, Benedikt; Franke, Steffen; Taube, Wolfgang; Gollhofer, Albert

2017-04-07

Increasing evidence suggests that cardiovascular exercise has positive effects on motor memory consolidation. In this study, we investigated whether a single session of high-intensity interval training (HIIT) mitigates the effects of practicing an interfering motor task. Furthermore, learning and interference effects were assessed in the actively trained and untrained limb as it is known that unilateral motor learning can cause bilateral adaptations. Subjects performed a ballistic training and then the HIIT either before (HIIT_before) or after (HIIT_after) practicing an interfering accuracy task (AT). The control group (No_HIIT) did not participate in the HIIT but rested instead. Performance in the ballistic task (BT) was tested before and after the ballistic training, after the exercise and practice of the AT and 24h later. After ballistic training, all groups showed comparable increases in performance in the trained and untrained limb. Despite the practice of the AT, HIIT_before maintained their BT performance after the high-intensity interval training whereas HIIT_after (trend) & No_HIIT showed prominent interference effects. After 24h, HIIT_before still did not show any interference effects but further improved ballistic motor performance. HIIT_after counteracted the interference resulting in a comparable BT performance after 24h than directly after the ballistic training while No_HIIT had a significantly lower BT performance in the retention test. The results were similar in the trained and untrained limb. The current results imply that a single session of cardiovascular exercise can prevent motor interference in the trained and untrained hemisphere. Overall learning was best, and interference least, when HIIT was performed before the interfering motor task. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

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.

Domestic violence and employment: a qualitative study.

PubMed

Swanberg, Jennifer E; Logan, T K

2005-01-01

This exploratory study sought to gather detailed information about how domestic violence affects women's employment, specifically to identify the types of job interference tactics used by abusers and their consequences on women's job performance; identify and understand the context associated with disclosure about victimization to employers and coworkers; and identify the supports offered to employees after disclosure. Qualitative analyses, guided by grounded theory, revealed that perpetrators exhibited job interference behaviors before, during, and after work. Abuser tactics reduced women's job performance as measured by absenteeism, tardiness, job leavings, and terminations. Among women who disclosed victimization to employers, informal and formal job supports were offered. Workplace supports led to short-term job retention, but fear and safety issues mitigated employers' attempts to retain workers. ((c) 2005 APA, all rights reserved).

HC-HA/PTX3 Purified From Amniotic Membrane as Novel Regenerative Matrix: Insight Into Relationship Between Inflammation and Regeneration.

PubMed

Tseng, Scheffer C G

2016-04-01

Human limbal palisade of Vogt is an ideal model for studying and practicing regenerative medicine due to their accessibility. Nonresolving inflammation is a common manifestation of limbal stem cell deficiency, which is the major cause of corneal blindness, and presents as a threat to the success of transplanted limbal epithelial stem cells. Clinical studies have shown that the efficacy of transplantation of limbal epithelial stem cells can be augmented by transplantation of cryopreserved human amniotic membrane (AM), which exerts anti-inflammatory, antiscarring, and antiangiogenic action to promote wound healing. Review of published data to determine the molecular action mechanism explaining how AM exerts the aforementioned therapeutic actions. From the water-soluble extract of cryopreserved AM, we have biochemically purified one novel matrix component termed heavy chain (HC)-hyaluronan (HA)/pentraxin 3 (PTX3) as the key relevant tissue characteristic responsible for the aforementioned AM's efficacy. Heavy chain-HA is a complex formed by a covalent linkage between HA and HC1 of inter-α-trypsin inhibitor (IαI) by tumor necrosis factor-stimulated gene-6 (TSG-6). This complex may then be tightly associated with PTX3 to form HC-HA/PTX3 complex. Besides exerting an anti-inflammatory, antiscarring, and antiangiogenic effects, HC-HA/PTX3 complex also uniquely maintains limbal niche cells to support the quiescence of limbal epithelial stem cells. We envision that HC-HA/PTX3 purified from AM can be used as a unique substrate to refine ex vivo expansion of limbal epithelial stem cells by maintaining stem cell quiescence, self-renewal and fate decision. Furthermore, it can also be deployed as a platform to launch new therapeutics in regenerative medicine by mitigating nonresolving inflammation and reinforcing the well-being of stem cell niche.

Optimization of morphological parameters for mitigation pits on rear KDP surface: experiments and numerical modeling.

PubMed

Yang, Hao; Cheng, Jian; Chen, Mingjun; Wang, Jian; Liu, Zhichao; An, Chenhui; Zheng, Yi; Hu, Kehui; Liu, Qi

2017-07-24

In high power laser systems, precision micro-machining is an effective method to mitigate the laser-induced surface damage growth on potassium dihydrogen phosphate (KDP) crystal. Repaired surfaces with smooth spherical and Gaussian contours can alleviate the light field modulation caused by damage site. To obtain the optimal repairing structure parameters, finite element method (FEM) models for simulating the light intensification caused by the mitigation pits on rear KDP surface were established. The light intensity modulation of these repairing profiles was compared by changing the structure parameters. The results indicate the modulation is mainly caused by the mutual interference between the reflected and incident lights on the rear surface. Owing to the total reflection, the light intensity enhancement factors (LIEFs) of the spherical and Gaussian mitigation pits sharply increase when the width-depth ratios are near 5.28 and 3.88, respectively. To achieve the optimal mitigation effect, the width-depth ratios greater than 5.3 and 4.3 should be applied to the spherical and Gaussian repaired contours. Particularly, for the cases of width-depth ratios greater than 5.3, the spherical repaired contour is preferred to achieve lower light intensification. The laser damage test shows that when the width-depth ratios are larger than 5.3, the spherical repaired contour presents higher laser damage resistance than that of Gaussian repaired contour, which agrees well with the simulation results.

School Performance and Disease Interference in Adolescents with Sickle Cell Disease

ERIC Educational Resources Information Center

Crosby, Lori E.; Joffe, Naomi E.; Irwin, Mary Kay; Strong, Heather; Peugh, James; Shook, Lisa; Kalinyak, Karen A.; Mitchell, Monica J.

2015-01-01

Sickle cell disease (SCD) results in neuropsychological complications that place adolescents at higher risk for limited educational achievement. A first step to developing effective educational interventions is to understand the impact of SCD on school performance. The current study assessed perceptions of school performance, SCD interference and…

Adaptive Significance of Flexistyly in Alpinia blepharocalyx (Zingiberaceae): A Hand-pollination Experiment

PubMed Central

Sun, Shan; Gao, Jiang-Yun; Liao, Wan-Jin; Li, Qing-Jun; Zhang, Da-Yong

2007-01-01

Background and Aims Flexistyly is a sexual dimorphism where there are two morphs that differ in the temporal expression of sexual function and also involve reciprocal movement of the stigmatic surface through a vertical axis during the flowering period. The adaptive significance of flexistyly has been interpreted as a floral mechanism for outcrossing, but it may also function to reduce sexual interference in which styles and stigmas impede the pollen export. Here these two explanations of flexistyly were tested in Alpinia blepharocalyx through a hand-pollination experiment. Methods Hand-pollinations were performed in two temporal morphs and consisted of two sequential pollination treatments, namely self-pollination in the morning and inter-morph pollination in the afternoon (treatment 1) or conversely inter-morph pollination in the morning and self-pollination in the afternoon (treatment 2), and two simultaneous self- and inter-morph cross-pollination treatments either in the morning (treatment 3) or in the afternoon (treatment 4). Seed paternity was then determined to assess relative success of self- versus cross-pollen using allozyme markers. Key Results In the sequential pollination treatments, whether the stigmas of recipients are receptive in the morning is crucial to the success of the pollen deposited. When the cataflexistylous (protandrous) morph served as pollen recipient, early-arriving pollen in the morning can sire only a very small proportion (<15%) of seeds because the stigmas were then unreceptive. However, when the anaflexistylous (protogynous) morph served as pollen recipient, early pollen did gain a large competitive advantage over the late pollen, particularly when cross-pollen arrived first. Simultaneous self- and inter-morph cross-pollination indicated that outcross-pollen is more competitive than self-pollen on receptive stigmas. Conclusions Differential maturing of male and female organs in Alpinia blepharocalyx is sufficient for selfing avoidance, obviating the need for style movements. Instead, the upward style curvature of the cataflexistylous morph in the morning and the anaflexistylous morph in the afternoon most likely represents a means of reducing interference with pollen export. PMID:17237211

The impact of junior doctors' worktime arrangements on their fatigue and well-being.

PubMed

Tucker, Philip; Brown, Menna; Dahlgren, Anna; Davies, Gwyneth; Ebden, Philip; Folkard, Simon; Hutchings, Hayley; Akerstedt, Torbjörn

2010-11-01

Many doctors report working excessively demanding schedules that comply with the European Working Time Directive (EWTD). We compared groups of junior doctors working on different schedules in order to identify which features of schedule design most negatively affected their fatigue and well-being in recent weeks. Completed by 336 doctors, the questionnaires focused on the respondents' personal circumstances, work situation, work schedules, sleep, and perceptions of fatigue, work-life balance and psychological strain. Working 7 consecutive nights was associated with greater accumulated fatigue and greater work-life interference, compared with working just 3 or 4 nights. Having only 1 rest day after working nights was associated with increased fatigue. Working a weekend on-call between 2 consecutive working weeks was associated with increased work-life interference. Working frequent on-calls (either on weekends or during the week) was associated with increased work-life interference and psychological strain. Inter-shift intervals of <10 hours were associated with shorter periods of sleep and increased fatigue. The number of hours worked per week was positively associated with work-life interference and fatigue on night shifts. The current findings identify parameters, in addition to those specified in the EWTD, for designing schedules that limit their impact on doctors' fatigue and well-being.

Different effects of enhanced and reduced expression of pub gene on the formation of embryoid bodies by cultured embryonic mouse stem cell.

PubMed

Novosadova, E V; Manuilova, E S; Arsen'eva, E L; Khaidarova, N V; Dolotov, O V; Inozemtseva, L S; Kozachenkov, K Yu; Tarantul, V Z; Grivennikov, I A

2005-07-01

The effects of pub gene on proliferation and initial stages of differentiation of embryonic mouse stem cells were studied in vitro. To this end we used enhanced expression of human pub gene (hpub) and suppression of expression of mouse endogenous pub gene with RNA-interference in embryonic stem cells. Proliferative activity of genetically modified polyclonal lines of the embryonic stem cells transfected with plasmids carrying expressing hpub gene or plasmids generating small interference RNA to this gene did not differ from that of the control cells. Inhibition of expression of endogenous pub gene in embryonic stem cells using small interference RNA 2-fold decreased the formation of embryoid bodies, at the same time additional expression of exogenous hpub gene almost 2-fold increased their number in comparison with the control. It was hypothesized that pub gene participates in early stages of differentiation of embryonic stem cells leading to the formation of embryoid bodies.

Lovastatin in Aspergillus terreus: fermented rice straw extracts interferes with methane production and gene expression in Methanobrevibacter smithii.

PubMed

Faseleh Jahromi, Mohammad; Liang, Juan Boo; Ho, Yin Wan; Mohamad, Rosfarizan; Goh, Yong Meng; Shokryazdan, Parisa; Chin, James

2013-01-01

Lovastatin, a natural byproduct of some fungi, is able to inhibit HMG-CoA (3-hydroxy-3 methyl glutaryl CoA) reductase. This is a key enzyme involved in isoprenoid synthesis and essential for cell membrane formation in methanogenic Archaea. In this paper, experiments were designed to test the hypothesis that lovastatin secreted by Aspergillus terreus in fermented rice straw extracts (FRSE) can inhibit growth and CH4 production in Methanobrevibacter smithii (a test methanogen). By HPLC analysis, 75% of the total lovastatin in FRSE was in the active hydroxyacid form, and in vitro studies confirmed that this had a stronger effect in reducing both growth and CH4 production in M. smithii compared to commercial lovastatin. Transmission electron micrographs revealed distorted morphological divisions of lovastatin- and FRSE-treated M. smithii cells, supporting its role in blocking normal cell membrane synthesis. Real-time PCR confirmed that both commercial lovastatin and FRSE increased (P < 0.01) the expression of HMG-CoA reductase gene (hmg). In addition, expressions of other gene transcripts in M. smithii. with a key involvement in methanogenesis were also affected. Experimental confirmation that CH4 production is inhibited by lovastatin in A. terreus-fermented rice straw paves the way for its evaluation as a feed additive for mitigating CH4 production in ruminants.

Bone marrow mesenchymal stem cells protect against n-hexane-induced neuropathy through beclin 1-independent inhibition of autophagy.

PubMed

Hao, Jie; Li, Shuangyue; Shi, Xiaoxia; Qian, Zhiqiang; Sun, Yijie; Wang, Dunjia; Zhou, Xueying; Qu, Hongxin; Hu, Shuhai; Zuo, Enjun; Zhang, Cong; Hou, Liyan; Wang, Qingshan; Piao, Fengyuan

2018-03-14

Chronic exposure to n-hexane, a widely used organic solvent in industry, induces central-peripheral neuropathy, which is mediated by its active metabolite, 2,5-hexanedione (HD). We recently reported that transplantation of bone marrow-mesenchymal stem cells (BMSC) significantly ameliorated HD-induced neuronal damage and motor deficits in rats. However, the mechanisms remain unclear. Here, we reported that inhibition of HD-induced autophagy contributed to BMSC-afforded protection. BMSC transplantation significantly reduced the levels of microtubule-associated protein 1 light chain 3-II (LC3-II) and the degradation of sequestosome-1 (p62) in the spinal cord and sciatic nerve of HD-intoxicated rats. Downregulation of autophagy by BMSC was also confirmed in VSC4.1 cells exposed to HD. Moreover, inhibition of autophagy by PIK III mitigated the neurotoxic effects of HD and, meanwhile, abolished BMSC-afforded neuroprotection. Furthermore, we found that BMSC failed to interfere with Beclin 1, but promoted activation of mammalian target of rapamycin (mTOR). Unc-like kinse 1 (ULK1) was further recognized as the downstream target of mTOR responsible for BMSC-mediated inhibition of autophagy. Altogether, BMSC transplantation potently ameliorated HD-induced autophagy through beclin 1-independent activation of mTOR pathway, providing a novel insight for the therapeutic effects of BMSC against n-hexane and other environmental toxicants-induced neurotoxicity.

Lovastatin in Aspergillus terreus: Fermented Rice Straw Extracts Interferes with Methane Production and Gene Expression in Methanobrevibacter smithii

PubMed Central

Liang, Juan Boo; Ho, Yin Wan; Mohamad, Rosfarizan; Goh, Yong Meng; Shokryazdan, Parisa; Chin, James

2013-01-01

Lovastatin, a natural byproduct of some fungi, is able to inhibit HMG-CoA (3-hydroxy-3methyl glutaryl CoA) reductase. This is a key enzyme involved in isoprenoid synthesis and essential for cell membrane formation in methanogenic Archaea. In this paper, experiments were designed to test the hypothesis that lovastatin secreted by Aspergillus terreus in fermented rice straw extracts (FRSE) can inhibit growth and CH4 production in Methanobrevibacter smithii (a test methanogen). By HPLC analysis, 75% of the total lovastatin in FRSE was in the active hydroxyacid form, and in vitro studies confirmed that this had a stronger effect in reducing both growth and CH4 production in M. smithii compared to commercial lovastatin. Transmission electron micrographs revealed distorted morphological divisions of lovastatin- and FRSE-treated M. smithii cells, supporting its role in blocking normal cell membrane synthesis. Real-time PCR confirmed that both commercial lovastatin and FRSE increased (P < 0.01) the expression of HMG-CoA reductase gene (hmg). In addition, expressions of other gene transcripts in M. smithii. with a key involvement in methanogenesis were also affected. Experimental confirmation that CH4 production is inhibited by lovastatin in A. terreus-fermented rice straw paves the way for its evaluation as a feed additive for mitigating CH4 production in ruminants. PMID:23710454

Initial Approaches to Mitigating the Impacts of the AWS-3 Auction (1755-1780 MHz)

DTIC Science & Technology

2015-05-13

band. Specifically, the impact of new Long Term Evolution – Advanced ( LTE -A) services on AMT operations at the Edwards Range. 15. SUBJECT TERMS...AWS-3, Aeronautical Mobile Telemetry, LTE -A, Transition Plan, Transmitters, Receivers, Antenna Systems, Bandwidth Efficient Modulation, Spectrum 16...occupants of the adjacent band which is expected to be 4G LTE -Advanced services • More potential for RF interference from commercial services • Band will

Peculiarities of studying an isolated neuron by the method of laser interference microscopy

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

Yusipovich, Alexander I; Kazakova, Tatiana A; Erokhova, Liudmila A

2006-09-30

Actual aspects of using a new method of laser interference microscopy (LIM) for studying nerve cells are discussed. The peculiarities of the LIM display of neurons are demonstrated by the example of isolated neurons of a pond snail Lymnaea stagnalis. A comparative analysis of the images of the cell and subcellular structures of a neuron obtained by the methods of interference microscopy, optical transmission microscopy, and confocal microscopy is performed. Various aspects of the application of LIM for studying the lateral dimensions and internal structure of the cytoplasm and organelles of a neuron in cytology and cell physiology are discussed.more » (laser biology)« less

Parasol cell mosaics are unlikely to drive the formation of structured orientation maps in primary visual cortex.

PubMed

Hore, Victoria R A; Troy, John B; Eglen, Stephen J

2012-11-01

The receptive fields of on- and off-center parasol cell mosaics independently tile the retina to ensure efficient sampling of visual space. A recent theoretical model represented the on- and off-center mosaics by noisy hexagonal lattices of slightly different density. When the two lattices are overlaid, long-range Moiré interference patterns are generated. These Moiré interference patterns have been suggested to drive the formation of highly structured orientation maps in visual cortex. Here, we show that noisy hexagonal lattices do not capture the spatial statistics of parasol cell mosaics. An alternative model based upon local exclusion zones, termed as the pairwise interaction point process (PIPP) model, generates patterns that are statistically indistinguishable from parasol cell mosaics. A key difference between the PIPP model and the hexagonal lattice model is that the PIPP model does not generate Moiré interference patterns, and hence stimulated orientation maps do not show any hexagonal structure. Finally, we estimate the spatial extent of spatial correlations in parasol cell mosaics to be only 200-350 μm, far less than that required to generate Moiré interference. We conclude that parasol cell mosaics are too disordered to drive the formation of highly structured orientation maps in visual cortex.

Effects of nicotine on response inhibition and interference control.

PubMed

Ettinger, Ulrich; Faiola, Eliana; Kasparbauer, Anna-Maria; Petrovsky, Nadine; Chan, Raymond C K; Liepelt, Roman; Kumari, Veena

2017-04-01

Nicotine is a cholinergic agonist with known pro-cognitive effects in the domains of alerting and orienting attention. However, its effects on attentional top-down functions such as response inhibition and interference control are less well characterised. Here, we investigated the effects of 7 mg transdermal nicotine on performance on a battery of response inhibition and interference control tasks. A sample of N = 44 healthy adult non-smokers performed antisaccade, stop signal, Stroop, go/no-go, flanker, shape matching and Simon tasks, as well as the attentional network test (ANT) and a continuous performance task (CPT). Nicotine was administered in a within-subjects, double-blind, placebo-controlled design, with order of drug administration counterbalanced. Relative to placebo, nicotine led to significantly shorter reaction times on a prosaccade task and on CPT hits but did not significantly improve inhibitory or interference control performance on any task. Instead, nicotine had a negative influence in increasing the interference effect on the Simon task. Nicotine did not alter inter-individual associations between reaction times on congruent trials and error rates on incongruent trials on any task. Finally, there were effects involving order of drug administration, suggesting practice effects but also beneficial nicotine effects when the compound was administered first. Overall, our findings support previous studies showing positive effects of nicotine on basic attentional functions but do not provide direct evidence for an improvement of top-down cognitive control through acute administration of nicotine at this dose in healthy non-smokers.

Implementation of parallel transmit beamforming using orthogonal frequency division multiplexing--achievable resolution and interbeam interference.

PubMed

Demi, Libertario; Viti, Jacopo; Kusters, Lieneke; Guidi, Francesco; Tortoli, Piero; Mischi, Massimo

2013-11-01

The speed of sound in the human body limits the achievable data acquisition rate of pulsed ultrasound scanners. To overcome this limitation, parallel beamforming techniques are used in ultrasound 2-D and 3-D imaging systems. Different parallel beamforming approaches have been proposed. They may be grouped into two major categories: parallel beamforming in reception and parallel beamforming in transmission. The first category is not optimal for harmonic imaging; the second category may be more easily applied to harmonic imaging. However, inter-beam interference represents an issue. To overcome these shortcomings and exploit the benefit of combining harmonic imaging and high data acquisition rate, a new approach has been recently presented which relies on orthogonal frequency division multiplexing (OFDM) to perform parallel beamforming in transmission. In this paper, parallel transmit beamforming using OFDM is implemented for the first time on an ultrasound scanner. An advanced open platform for ultrasound research is used to investigate the axial resolution and interbeam interference achievable with parallel transmit beamforming using OFDM. Both fundamental and second-harmonic imaging modalities have been considered. Results show that, for fundamental imaging, axial resolution in the order of 2 mm can be achieved in combination with interbeam interference in the order of -30 dB. For second-harmonic imaging, axial resolution in the order of 1 mm can be achieved in combination with interbeam interference in the order of -35 dB.

Interference Drop Scheme: Enhancing QoS Provision in Multi-Hop Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Luo, Chang-Yi; Komuro, Nobuyoshi; Takahashi, Kiyoshi; Kasai, Hiroyuki; Ueda, Hiromi; Tsuboi, Toshinori

Ad hoc networking uses wireless technologies to construct networks with no physical infrastructure and so are expected to provide instant networking in areas such as disaster recovery sites and inter-vehicle communication. Unlike conventional wired networks services, services in ad hoc networks are easily disrupted by the frequent changes in traffic and topology. Therefore, solutions to assure the Quality of Services (QoS) in ad hoc networks are different from the conventional ones used in wired networks. In this paper, we propose a new queue management scheme, Interference Drop Scheme (IDS) for ad hoc networks. In the conventional queue management approaches such as FIFO (First-in First-out) and RED (Random Early Detection), a queue is usually managed by a queue length limit. FIFO discards packets according to the queue limit, and RED discards packets in an early and random fashion. IDS, on the other hand, manages the queue according to wireless interference time, which increases as the number of contentions in the MAC layer increases. When there are many MAC contentions, IDS discards TCP data packets. By observing the interference time and discarding TCP data packets, our simulation results show that IDS improves TCP performance and reduces QoS violations in UDP in ad hoc networks with chain, grid, and random topologies. Our simulation results also demonstrate that wireless interference time is a better metric than queue length limit for queue management in multi-hop ad hoc networks.

Effect of low body temperature on associative interference in conditioned taste aversion.

PubMed

Christianson, John P; Anderson, Mathew J; Misanin, James R; Hinderliter, Charles F

2005-06-01

When two novel conditioned stimuli precede an unconditioned stimulus (US), the interval between the two conditioned stimuli (CS1 and CS2) influences the magnitude of the CS-US associability of each CS. As the interval between CS1 and CS2 increases, the associability of CS1 with the US decreases due to interference by CS2 and the associability of CS2 increases, given its temporal proximity to the US. Because hypothermia has been reported to increase the interval at which conditioned taste aversions can be formed, its influence was examined on the above relationship, i.e., how interference from CS2 affects the associability of CS1 with the US. Rats received a conditioned taste aversion procedure where CS1 and CS2 were presented either one after the other or separated by an 80-min. delay. For all subjects, the US or pseudo-US was presented immediately after CS2. When hypothermia was interpolated between the two flavor stimuli that were spaced 80 min. apart, CS2-interference with the CS1-US association was greatly attenuated. We propose that hypothermia modifies internal timing mechanisms such that the externally timed 80-min. CS1-CS2 interval was perceived as much shorter for rats made hypothermic. As a result of this perceived shortened inter-CS interval, CS2 produced less interference for the CS1-US association than would be expected for such a relatively long delay between CS1 and CS2.

A Fast and Scalable Algorithm for Calculating the Achievable Capacity of a Wireless Mesh Network

DTIC Science & Technology

2016-05-09

an optimal wireless transmission schedule for a predetermined set of links without the addition of routing is NP-Hard [5]. We effectively bypass the... wireless communications have used omni-directional antennas, where a user’s transmission inter- feres with others users in all directions. Different...interference from some particular transmission . Hence, δ = ∆(Ḡc) = max(i,j)∈E |Fij |. IV. ALGORITHM FOR RAPIDLY DETERMINING WIRELESS NETWORK CAPACITY In

Psychological Analyses of Courageous Performance in Military Personnel

DTIC Science & Technology

1986-11-01

schedule HR heart rate IBI inter- beat interval N number of subjects NS not statistically significant P probability PCA principal components analysis RAQ...tones in the range of 400 to 600 Hz, set at a level of 60 dB, transmitted for 1 sec binaurally through earphones from a commercial oscillator. The...because of interference on the recording trace. Cardiac activity was measured in terms of heart rate (HR). The number of beats /minute was estimared by

John Glenn Biomedical Engineering Consortium

NASA Technical Reports Server (NTRS)

Nall, Marsha

2004-01-01

The John Glenn Biomedical Engineering Consortium is an inter-institutional research and technology development, beginning with ten projects in FY02 that are aimed at applying GRC expertise in fluid physics and sensor development with local biomedical expertise to mitigate the risks of space flight on the health, safety, and performance of astronauts. It is anticipated that several new technologies will be developed that are applicable to both medical needs in space and on earth.

Performance analysis of a finite radon transform in OFDM system under different channel models

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

Dawood, Sameer A.; Anuar, M. S.; Fayadh, Rashid A.

In this paper, a class of discrete Radon transforms namely Finite Radon Transform (FRAT) was proposed as a modulation technique in the realization of Orthogonal Frequency Division Multiplexing (OFDM). The proposed FRAT operates as a data mapper in the OFDM transceiver instead of the conventional phase shift mapping and quadrature amplitude mapping that are usually used with the standard OFDM based on Fast Fourier Transform (FFT), by the way that ensure increasing the orthogonality of the system. The Fourier domain approach was found here to be the more suitable way for obtaining the forward and inverse FRAT. This structure resultedmore » in a more suitable realization of conventional FFT- OFDM. It was shown that this application increases the orthogonality significantly in this case due to the use of Inverse Fast Fourier Transform (IFFT) twice, namely, in the data mapping and in the sub-carrier modulation also due to the use of an efficient algorithm in determining the FRAT coefficients called the optimal ordering method. The proposed approach was tested and compared with conventional OFDM, for additive white Gaussian noise (AWGN) channel, flat fading channel, and multi-path frequency selective fading channel. The obtained results showed that the proposed system has improved the bit error rate (BER) performance by reducing inter-symbol interference (ISI) and inter-carrier interference (ICI), comparing with conventional OFDM system.« less

Performance analysis of a finite radon transform in OFDM system under different channel models

NASA Astrophysics Data System (ADS)

Dawood, Sameer A.; Malek, F.; Anuar, M. S.; Fayadh, Rashid A.; Abdullah, Farrah Salwani

2015-05-01

In this paper, a class of discrete Radon transforms namely Finite Radon Transform (FRAT) was proposed as a modulation technique in the realization of Orthogonal Frequency Division Multiplexing (OFDM). The proposed FRAT operates as a data mapper in the OFDM transceiver instead of the conventional phase shift mapping and quadrature amplitude mapping that are usually used with the standard OFDM based on Fast Fourier Transform (FFT), by the way that ensure increasing the orthogonality of the system. The Fourier domain approach was found here to be the more suitable way for obtaining the forward and inverse FRAT. This structure resulted in a more suitable realization of conventional FFT- OFDM. It was shown that this application increases the orthogonality significantly in this case due to the use of Inverse Fast Fourier Transform (IFFT) twice, namely, in the data mapping and in the sub-carrier modulation also due to the use of an efficient algorithm in determining the FRAT coefficients called the optimal ordering method. The proposed approach was tested and compared with conventional OFDM, for additive white Gaussian noise (AWGN) channel, flat fading channel, and multi-path frequency selective fading channel. The obtained results showed that the proposed system has improved the bit error rate (BER) performance by reducing inter-symbol interference (ISI) and inter-carrier interference (ICI), comparing with conventional OFDM system.

A Two-Stage Approach for Improving the Convergence of Least-Mean-Square Adaptive Decision-Feedback Equalizers in the Presence of Severe Narrowband Interference

NASA Astrophysics Data System (ADS)

Batra, Arun; Zeidler, James R.; Beex, A. A. Louis

2007-12-01

It has previously been shown that a least-mean-square (LMS) decision-feedback filter can mitigate the effect of narrowband interference (L.-M. Li and L. Milstein, 1983). An adaptive implementation of the filter was shown to converge relatively quickly for mild interference. It is shown here, however, that in the case of severe narrowband interference, the LMS decision-feedback equalizer (DFE) requires a very large number of training symbols for convergence, making it unsuitable for some types of communication systems. This paper investigates the introduction of an LMS prediction-error filter (PEF) as a prefilter to the equalizer and demonstrates that it reduces the convergence time of the two-stage system by as much as two orders of magnitude. It is also shown that the steady-state bit-error rate (BER) performance of the proposed system is still approximately equal to that attained in steady-state by the LMS DFE-only. Finally, it is shown that the two-stage system can be implemented without the use of training symbols. This two-stage structure lowers the complexity of the overall system by reducing the number of filter taps that need to be adapted, while incurring a slight loss in the steady-state BER.

Quantitative interference by cysteine and N-acetylcysteine metabolites during the LC-MS/MS bioanalysis of a small molecule.

PubMed

Barricklow, Jason; Ryder, Tim F; Furlong, Michael T

2009-08-01

During LC-MS/MS quantification of a small molecule in human urine samples from a clinical study, an unexpected peak was observed to nearly co-elute with the analyte of interest in many study samples. Improved chromatographic resolution revealed the presence of at least 3 non-analyte peaks, which were identified as cysteine metabolites and N-acetyl (mercapturic acid) derivatives thereof. These metabolites produced artifact responses in the parent compound MRM channel due to decomposition in the ionization source of the mass spectrometer. Quantitative comparison of the analyte concentrations in study samples using the original chromatographic method and the improved chromatographic separation method demonstrated that the original method substantially over-estimated the analyte concentration in many cases. The substitution of electrospray ionization (ESI) for atmospheric pressure chemical ionization (APCI) nearly eliminated the source instability of these metabolites, which would have mitigated their interference in the quantification of the analyte, even without chromatographic separation. These results 1) demonstrate the potential for thiol metabolite interferences during the quantification of small molecules in pharmacokinetic samples, and 2) underscore the need to carefully evaluate LC-MS/MS methods for molecules that can undergo metabolism to thiol adducts to ensure that they are not susceptible to such interferences during quantification.

A model of work-family conflict and well-being among Malaysian working women.

PubMed

Aazami, Sanaz; Akmal, Syaqirah; Shamsuddin, Khadijah

2015-01-01

Work and family are the two most important domains in a person's life. Lack of balance between work and family can lead to adverse consequences such as psychological distress; however, the effect of work-family conflict on psychological distress might be mediated by job and family dissatisfaction. This study examines a model of the four dimensions of work-family conflict and their consequences on psychological distress. In particular, we test whether job and family satisfaction mediate the effect of the four dimensions of work-family conflict on psychological distress. This cross-sectional study was conducted among 567 Malaysian women who are working in the public services. Structural Equation Modeling confirmed the mediating role of family satisfaction in the effect of strain-based work interference into family and time-based family interference into work on psychological distress. In addition, our results revealed a significant path that links job to family satisfaction. Moreover, time-based work interference into family and strain-based family interference into work significantly and negatively affect job satisfaction, which in turn influence family satisfaction and eventually affect psychological distress. The results of our study show that organizations need to develop and adapt family friendly policies to mitigate level of employees' work-family conflict.

[Managing comprehensive care: a case study in a health district in Bahia State, Brazil].

PubMed

dos Santos, Adriano Maia; Giovanella, Ligia

2016-03-01

This study analyzed management of comprehensive care in a health district in Bahia State, Brazil, at the political, institutional, organizational, and healthcare practice levels and the challenges for establishing coordinated care between municipalities. The information sources were semi-structured interviews with administrators, focal groups with healthcare professionals and users, institutional documents, and observations. A comprehensive and critical analysis was produced with dialectical hermeneutics as the reference. The results show that the Inter-Administrators Regional Commission was the main regional governance strategy. There is a fragmentation between various points and lack of communications linkage in the network. Private interests and partisan political interference overlook the formally agreed-upon flows and create parallel circuits, turning the right to health into currency for trading favors. Such issues hinder coordination of comprehensive care in the inter-municipal network.

Electromagnetic Interference to Flight Navigation and Communication Systems: New Strategies in the Age of Wireless

NASA Technical Reports Server (NTRS)

Ely, Jay J.

2005-01-01

Electromagnetic interference (EMI) promises to be an ever-evolving concern for flight electronic systems. This paper introduces EMI and identifies its impact upon civil aviation radio systems. New wireless services, like mobile phones, text messaging, email, web browsing, radio frequency identification (RFID), and mobile audio/video services are now being introduced into passenger airplanes. FCC and FAA rules governing the use of mobile phones and other portable electronic devices (PEDs) on board airplanes are presented along with a perspective of how these rules are now being rewritten to better facilitate in-flight wireless services. This paper provides a comprehensive overview of NASA cooperative research with the FAA, RTCA, airlines and universities to obtain laboratory radiated emission data for numerous PED types, aircraft radio frequency (RF) coupling measurements, estimated aircraft radio interference thresholds, and direct-effects EMI testing. These elements are combined together to provide high-confidence answers regarding the EMI potential of new wireless products being used on passenger airplanes. This paper presents a vision for harmonizing new wireless services with aeronautical radio services by detecting, assessing, controlling and mitigating the effects of EMI.

Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on 0.1 Ma Toya Tephra, Japan" by Hisatoshi Ito

NASA Astrophysics Data System (ADS)

Guillong, M.; Schmitt, A. K.; Bachmann, O.

2015-04-01

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of eight zircon reference materials and synthetic zircon-hafnon end-members indicate that corrections for abundance sensitivity and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon. Other polyatomic interferences in the mass range 223-233 amu are insignificant. When corrected for abundance sensitivity and interferences, activity ratios of (230Th)/(238U) for the zircon reference materials we used average 1.001 ± 0.010 (1σ error; mean square of weighted deviates MSWD = 1.45; n = 8). This includes the 91500 and Plešovice zircons, which were deemed unsuitable for calibration of (230Th)/(238U) by Ito (2014). Uranium series zircon ages generated by LA-ICP-MS without mitigating (e.g., by high mass resolution) or correcting for abundance sensitivity and molecular interferences on 230Th such as those presented by Ito (2014) are potentially unreliable.

Mitigation of Laser Beam Scintillation in Free-Space Optical Communication Systems Through Coherence-Reducing Optical Materials

NASA Technical Reports Server (NTRS)

Renner, Christoffer J.

2005-01-01

Free-space optical communication systems (also known as lasercom systems) offer several performance advantages over traditional radio frequency communication systems. These advantages include increased data rates and reduced operating power and system weight. One serious limiting factor in a lasercom system is Optical turbulence in Earth's atmosphere. This turbulence breaks up the laser beam used to transmit the information into multiple segments that interfere with each other when the beam is focused onto the receiver. This interference pattern at the receiver changes with time causing fluctuations in the received optical intensity (scintillation). Scintillation leads to intermittent losses of the signal and an overall reduction in the lasercom system's performance. Since scintillation is a coherent effect, reducing the spatial and temporal coherence of the laser beam will reduce the scintillation. Transmitting a laser beam through certain materials is thought to reduce its coherence. Materials that were tested included: sapphire, BK7 glass, fused silica and others. The spatial and temporal coherence of the laser beam was determined by examining the interference patterns (fringes) it formed when interacting with various interferometers and etalons.

Joint Interference Alignment and Power Allocation for K-User Multicell MIMO Channel through Staggered Antenna Switching.

PubMed

Selvaprabhu, Poongundran; Chinnadurai, Sunil; Sarker, Md Abdul Latif; Lee, Moon Ho

2018-01-28

In this paper, we characterise the joint interference alignment (IA) and power allocation strategies for a K -user multicell multiple-input multiple-output (MIMO) Gaussian interference channel. We consider a MIMO interference channel with blind-IA through staggered antenna switching on the receiver. We explore the power allocation and feasibility condition for cooperative cell-edge (CE) mobile users (MUs) by assuming that the channel state information is unknown. The new insight behind the transmission strategy of the proposed scheme is premeditated (randomly generated transmission strategy) and partial cooperative CE MUs, where the transmitter is equipped with a conventional antenna, the receiver is equipped with a reconfigurable multimode antenna (staggered antenna switching pattern), and the receiver switches between preset T modes. Our proposed scheme assists and aligns the desired signals and interference signals to cancel the common interference signals because the received signal must have a corresponding independent signal subspace. The capacity for a K -user multicell MIMO Gaussian interference channel with reconfigurable multimode antennas is completely characterised. Furthermore, we show that the proposed K -user multicell MIMO scheduling and K -user L -cell CEUs partial cooperation algorithms elaborate the generalisation of K -user IA and power allocation strategies. The numerical results demonstrate that the proposed intercell interference scheme with partial-cooperative CE MUs achieves better capacity and signal-to-interference plus noise ratio (SINR) performance compared to noncooperative CE MUs and without intercell interference schemes.

Joint Interference Alignment and Power Allocation for K-User Multicell MIMO Channel through Staggered Antenna Switching

PubMed Central

2018-01-01

In this paper, we characterise the joint interference alignment (IA) and power allocation strategies for a K-user multicell multiple-input multiple-output (MIMO) Gaussian interference channel. We consider a MIMO interference channel with blind-IA through staggered antenna switching on the receiver. We explore the power allocation and feasibility condition for cooperative cell-edge (CE) mobile users (MUs) by assuming that the channel state information is unknown. The new insight behind the transmission strategy of the proposed scheme is premeditated (randomly generated transmission strategy) and partial cooperative CE MUs, where the transmitter is equipped with a conventional antenna, the receiver is equipped with a reconfigurable multimode antenna (staggered antenna switching pattern), and the receiver switches between preset T modes. Our proposed scheme assists and aligns the desired signals and interference signals to cancel the common interference signals because the received signal must have a corresponding independent signal subspace. The capacity for a K-user multicell MIMO Gaussian interference channel with reconfigurable multimode antennas is completely characterised. Furthermore, we show that the proposed K-user multicell MIMO scheduling and K-user L-cell CEUs partial cooperation algorithms elaborate the generalisation of K-user IA and power allocation strategies. The numerical results demonstrate that the proposed intercell interference scheme with partial-cooperative CE MUs achieves better capacity and signal-to-interference plus noise ratio (SINR) performance compared to noncooperative CE MUs and without intercell interference schemes. PMID:29382100

Airborne Remote Observations of L-Band Radio Frequency Interference and Implications for Satellite Missions

NASA Technical Reports Server (NTRS)

Laymon, Charles; Srinivasan, Karthik; Limaye, Ashutosh

2011-01-01

Passive remote sensing of the Earth s surface and atmosphere from space has significant importance in operational and research environmental studies, in particular for the scientific understanding, monitoring and prediction of climate change and its impacts. Passive remote sensing requires the measurement of naturally occurring radiations, usually of very low power levels, which contain essential information on the physical process under investigation. As such, these sensed radio frequency bands are a unique natural resource enabling space borne passive sensing of the atmosphere and the Earth s surface that deserves adequate allocation to the Earth Exploration Satellite Service and absolute protection from interference. Unfortunately, radio frequency interference (RFI) is an increasing problem for Earth remote sensing, particularly for passive observations of natural emissions. Because these natural signals tend to be very weak, even low levels of interference received by a passive sensor may degrade the fidelity of scientific data. The characteristics of RFI (low-level interference and radar-pulse noise) are not well known because there has been no systematic surveillance, spectrum inventory or mapping of RFI. While conducting a flight experiment over central Tennessee in May 2010, RFI, a concern for any instrument operating in the passive L band frequency, was observed across 16 subbands between 1402-1427 MHz. Such a survey provides rare characterization data from which to further develop mitigation technologies as well as to identify bandwidths to avoid in future sensor formulation.

Cell Wall Structure of Coccoid Green Algae as an Important Trade-Off Between Biotic Interference Mechanisms and Multidimensional Cell Growth.

PubMed

Dunker, Susanne; Wilhelm, Christian

2018-01-01

Coccoid green algae can be divided in two groups based on their cell wall structure. One group has a highly chemical resistant cell wall (HR-cell wall) containing algaenan. The other group is more susceptible to chemicals (LR-cell wall - Low resistant cell wall). Algaenan is considered as important molecule to explain cell wall resistance. Interestingly, cell wall types (LR- and HR-cell wall) are not in accordance with the taxonomic classes Chlorophyceae and Trebouxiophyceae, which makes it even more interesting to consider the ecological function. It was already shown that algaenan helps to protect against virus, bacterial and fungal attack, but in this study we show for the first time that green algae with different cell wall properties show different sensitivity against interference competition with the cyanobacterium Microcystis aeruginosa . Based on previous work with co-cultures of M. aeruginosa and two green algae ( Acutodesmus obliquus and Oocystis marssonii ) differing in their cell wall structure, it was shown that M. aeruginosa could impair only the growth of the green algae if they belong to the LR-cell wall type. In this study it was shown that the sensitivity to biotic interference mechanism shows a more general pattern within coccoid green algae species depending on cell wall structure.

Spectral resampling based on user-defined inter-band correlation filter: C3 and C4 grass species classification

NASA Astrophysics Data System (ADS)

Adjorlolo, Clement; Mutanga, Onisimo; Cho, Moses A.; Ismail, Riyad

2013-04-01

In this paper, a user-defined inter-band correlation filter function was used to resample hyperspectral data and thereby mitigate the problem of multicollinearity in classification analysis. The proposed resampling technique convolves the spectral dependence information between a chosen band-centre and its shorter and longer wavelength neighbours. Weighting threshold of inter-band correlation (WTC, Pearson's r) was calculated, whereby r = 1 at the band-centre. Various WTC (r = 0.99, r = 0.95 and r = 0.90) were assessed, and bands with coefficients beyond a chosen threshold were assigned r = 0. The resultant data were used in the random forest analysis to classify in situ C3 and C4 grass canopy reflectance. The respective WTC datasets yielded improved classification accuracies (kappa = 0.82, 0.79 and 0.76) with less correlated wavebands when compared to resampled Hyperion bands (kappa = 0.76). Overall, the results obtained from this study suggested that resampling of hyperspectral data should account for the spectral dependence information to improve overall classification accuracy as well as reducing the problem of multicollinearity.

Isogenic blood-brain barrier models based on patient-derived stem cells display inter-individual differences in cell maturation and functionality.

PubMed

Patel, Ronak; Page, Shyanne; Al-Ahmad, Abraham Jacob

2017-07-01

The blood-brain barrier (BBB) constitutes an important component of the neurovascular unit formed by specialized brain microvascular endothelial cells (BMECs) surrounded by astrocytes, pericytes, and neurons. Recently, isogenic in vitro models of the BBB based on human pluripotent stem cells have been documented, yet the impact of inter-individual variability on the yield and phenotype of such models remains to be documented. In this study, we investigated the impact of inter-individual variability on the yield and phenotype of isogenic models of the BBB, using patient-derived induced pluripotent stem cells (iPSCs). Astrocytes, BMECs, and neurons were differentiated from four asymptomatic patient-derived iPSCs (two males, two females). We differentiated such cells using existing differentiation protocols and quantified expression of cell lineage markers, as well as BBB phenotype, barrier induction, and formation of neurite processes. iPSC-derived BMECs showed barrier properties better than hCMEC/D3 monolayers; however, we noted differences in the expression and activity among iPSC lines. In addition, we noted differences in the differentiation efficiency of these cells into neural stem cells and progenitor cells (as noted by differences in expression of cell lineage markers). Such differences were reflected later in the terminal differentiation, as seen as ability to induce barrier function and to form neurite processes. Although we demonstrated our ability to obtain an isogenic model of the BBB with different patients' iPSCs, we also noted subtle differences in the expression of cell lineage markers and cell maturation processes, suggesting the presence of inter-individual polymorphisms. © 2017 International Society for Neurochemistry.

Incentive and Architecture of Multi-Band Enabled Small Cell and UE for Up-/Down-Link and Control-/User-Plane Splitting for 5G Mobile Networks

NASA Astrophysics Data System (ADS)

Saha, Rony Kumer; Aswakul, Chaodit

2017-01-01

In this paper, a multi-band enabled femtocell base station (FCBS) and user equipment (UE) architecture is proposed in a multi-tier network that consists of small cells, including femtocells and picocells deployed over the coverage of a macrocell for splitting uplink and downlink (UL/DL) as well as control-plane and user-plane (C-/U-plane) for 5G mobile networks. Since splitting is performed at the same FCBS, we define this architecture as the same base station based split architecture (SBSA). For multiple bands, we consider co-channel (CC) microwave and different frequency (DF) 60 GHz millimeter wave (mmWave) bands for FCBSs and UEs with respect to the microwave band used by their over-laid macrocell base station. All femtocells are assumed to be deployed in a 3-dimensional multi-storage building. For CC microwave band, cross-tier CC interference of femtocells with macrocell is avoided using almost blank subframe based enhanced inter-cell interference coordination techniques. The co-existence of CC microwave and DF mmWave bands for SBSA on the same FCBS and UE is first studied to show their performance disparities in terms of system capacity and spectral efficiency in order to provide incentives for employing multiple bands at the same FCBS and UE and identify a suitable band for routing decoupled UL/DL or C-/U-plane traffic. We then present a number of disruptive architectural design alternatives of multi-band enabled SBSA for 5G mobile networks for UL/DL and C-/U-plane splitting, including a disruptive and complete splitting of UL/DL and C-/U-plane as well as a combined UL/DL and C-/U-plane splitting, by exploiting dual connectivity on CC microwave and DF mmWave bands. The outperformances of SBSA in terms of system level capacity, average spectral efficiency, energy efficiency, and control-plane overhead traffic capacity in comparison with different base stations based split architecture (DBSA) are shown. Finally, a number of technical and business perspectives as well as key research issues of SBSA are discussed.

Improving receiver performance of diffusive molecular communication with enzymes.

PubMed

Noel, Adam; Cheung, Karen C; Schober, Robert

2014-03-01

This paper studies the mitigation of intersymbol interference in a diffusive molecular communication system using enzymes that freely diffuse in the propagation environment. The enzymes form reaction intermediates with information molecules and then degrade them so that they cannot interfere with future transmissions. A lower bound expression on the expected number of molecules measured at the receiver is derived. A simple binary receiver detection scheme is proposed where the number of observed molecules is sampled at the time when the maximum number of molecules is expected. Insight is also provided into the selection of an appropriate bit interval. The expected bit error probability is derived as a function of the current and all previously transmitted bits. Simulation results show the accuracy of the bit error probability expression and the improvement in communication performance by having active enzymes present.

Adjacent Channel Interference Reduction for M-WiMAX TDD and WCDMA FDD Coexistence by Utilizing Beamforming in M-WiMAX TDD System

NASA Astrophysics Data System (ADS)

Wang, Yupeng; Chang, Kyunghi

In this paper, we analyze the coexistence issues of M-WiMAX TDD and WCDMA FDD systems. Smart antenna techniques are applied to mitigate the performance loss induced by adjacent channel interference (ACI) in the scenarios where performance is heavily degraded. In addition, an ACI model is proposed to capture the effect of transmit beamforming at the M-WiMAX base station. Furthermore, a MCS-based throughput analysis is proposed, to jointly consider the effects of ACI, system packet error rate requirement, and the available modulation and coding schemes, which is not possible by using the conventional Shannon equation based analysis. From the results, we find that the proposed MCS-based analysis method is quite suitable to analyze the system theoretical throughput in a practical manner.

Hawaiian cultural influences on support for lava flow hazard mitigation measures during the January 1960 eruption of Kīlauea volcano, Kapoho, Hawai‘i

USGS Publications Warehouse

Gregg, Chris E.; Houghton, Bruce F.; Paton, Douglas; Swanson, D.A.; Lachman, R.; Bonk, W.J.

2008-01-01

On average, 72% of respondents favored the construction of earthen barriers to hold back or divert lava and protect Kapoho, but far fewer agreed with the military's use of bombs (14%) to protect Kapoho. In contrast, about one-third of respondents conditionally agreed with the use of bombs. It is suggested that local participation in the bombing strategy may explain the increased conditional acceptance of bombs as a mitigation tool, although this can not be conclusively demonstrated. Belief in Pele and being of Hawaiian ethnicity did not reduce support for the use of barriers, but did reduce support for bombs in both bombing scenarios. The disparity in levels of acceptance of barriers versus bombing and of one bombing strategy versus another suggests that historically public attitudes toward lava flow hazard mitigation strategies were complex. A modern comparative study is needed before the next damaging eruption to inform debates and decisions about whether or not to interfere with the flow of lava. Recent changes in the current eruption of Kīlauea make this a timely topic.

Turbulence mitigation scheme based on spatial diversity in orbital-angular-momentum multiplexed system

NASA Astrophysics Data System (ADS)

Zou, Li; Wang, Le; Zhao, Shengmei

2017-10-01

Atmospheric turbulence (AT) induced crosstalk can significantly impair the performance of free-space optical (FSO) communication link using orbital angular momentum (OAM) multiplexing. In this paper, we propose a spatial diversity (SD) turbulence mitigation scheme in an OAM-multiplexed FSO communication link. First, we present a SD mitigation model for the OAM-multiplexed FSO communication link under AT. Then we present a SD combining technique based on equal gain to enhance AT tolerance of the OAM-multiplexed FSO communication link. The numerical results show that performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme. When the turbulence strength Cn2 is 5 × 10-15m - 2 / 3, the transmission distance is 1000 m and the channel signal-to-noise ratio (SNR) is 20 dB, the bit-error-rate (BER) performance of four spatial multiplexed OAM modes lm = + 1 , + 2 , + 3 , + 4 are 3 fold increase in comparison with those results without the proposed scheme. The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.

A Simple Laboratory Practical to Illustrate RNA Mediated Gene Interference Using Drosophila Cell Culture

ERIC Educational Resources Information Center

Buluwela, Laki; Kamalati, Tahereh; Photiou, Andy; Heathcote, Dean A.; Jones, Michael D.; Ali, Simak

2010-01-01

RNA mediated gene interference (RNAi) is now a key tool in eukaryotic cell and molecular biology research. This article describes a five session laboratory practical, spread over a seven day period, to introduce and illustrate the technique. During the exercise, students working in small groups purify PCR products that encode "in vitro"…

Effects of Cinnamoyloxy-mammeisin from Geopropolis on Osteoclast Differentiation and Porphyromonas gingivalis-Induced Periodontitis.

PubMed

da Cunha, Marcos Guilherme; Ramos-Junior, Erivan Schnaider; Franchin, Marcelo; Taira, Thaise Mayumi; Beutler, John A; Franco, Gilson Cesar Nobre; Ikegaki, Masaharu; de Alencar, Severino Matias; Fukada, Sandra Yasuyo; Rosalen, Pedro Luiz

2017-06-23

Bone-loss-related diseases such as rheumatoid arthritis, osteomyelitis, osteoporosis, and periodontitis are associated with high rates of morbidity worldwide. These disorders are characterized by an imbalance between the formation and activity of osteoblasts and osteoclasts, leading to bone loss. In this context, we evaluated the effect of cinnamoyloxy-mammeisin (CNM), an anti-inflammatory coumarin found in Melipona scutellaris geopropolis, on key targets related to bone remodeling. In the present study we investigated the in vitro effects of CNM on osteoclast differentiation and M-CSF+RANKL-induced osteoclastogenic marker expression. Additionally, the interference of CNM treatment on osteoclast activity was evaluated by zymography and resorption area. Finally, we assessed the capacity of the compound to mitigate alveolar bone loss in vivo in experimental murine periodontitis induced by Porphyromonas gingivalis. We observed that treatment with CNM impaired osteoclast differentiation, as evidenced by a reduced number of tartrate-resistant acid-phosphatase-positive multinucleated cells (TRAP+) as well as the expression of osteoclastogenic markers upon M-CSF+RANKL-induced stimulation. Similarly, we observed reduced gelatinolytic and resorption capacity in M-CSF+RANKL-induced cells in vitro. Lastly, CNM attenuated alveolar bone loss in an experimental murine periodontitis model. These findings indicate that CNM may be considered a promising treatment for bone loss diseases.

Monitoring Interactions Inside Cells by Advanced Spectroscopies: Overview of Copper Transporters and Cisplatin.

PubMed

Lasorsa, Alessia; Natile, Giovanni; Rosato, Antonio; Tadini-Buoninsegni, Francesco; Arnesano, Fabio

2018-02-12

Resistance, either at the onset of the treatment or developed after an initial positive response, is a major limitation of antitumor therapy. In the case of platinum- based drugs, copper transporters have been found to interfere with drug trafficking by facilitating the import or favoring the platinum export and inactivation. The use of powerful spectroscopic, spectrometric and computational methods has allowed a deep structural insight into the mode of interaction of platinum drugs with the metal-binding domains of the transporter proteins. This review article focuses on the mode in which platinum drugs can compete with copper ion for binding to transport proteins and consequent structural and biological effects. Three types of transporters are discussed in detail: copper transporter 1 (Ctr1), the major responsible for Cu+ uptake; antioxidant-1 copper chaperone (Atox1), responsible for copper transfer within the cytoplasm; and copper ATPases (ATP7A/B), responsible for copper export into specific subcellular compartments and outside the cell. The body of knowledge summarized in this review can help in shaping current chemotherapy to optimize the efficacy of platinum drugs (particularly in relation to resistance) and to mitigate adverse effects on copper metabolism. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Preparing for Euro 2012: developing a hazard risk assessment.

PubMed

Wong, Evan G; Razek, Tarek; Luhovy, Artem; Mogilevkina, Irina; Prudnikov, Yuriy; Klimovitskiy, Fedor; Yutovets, Yuriy; Khwaja, Kosar A; Deckelbaum, Dan L

2015-04-01

Risk assessment is a vital step in the disaster-preparedness continuum as it is the foundation of subsequent phases, including mitigation, response, and recovery. To develop a risk assessment tool geared specifically towards the Union of European Football Associations (UEFA) Euro 2012. In partnership with the Donetsk National Medical University, Donetsk Research and Development Institute of Traumatology and Orthopedics, Donetsk Regional Public Health Administration, and the Ministry of Emergency of Ukraine, a table-based tool was created, which, based on historical evidence, identifies relevant potential threats, evaluates their impacts and likelihoods on graded scales based on previous available data, identifies potential mitigating shortcomings, and recommends further mitigation measures. This risk assessment tool has been applied in the vulnerability-assessment-phase of the UEFA Euro 2012. Twenty-three sub-types of potential hazards were identified and analyzed. Ten specific hazards were recognized as likely to very likely to occur, including natural disasters, bombing and blast events, road traffic collisions, and disorderly conduct. Preventative measures, such as increased stadium security and zero tolerance for impaired driving, were recommended. Mitigating factors were suggested, including clear, incident-specific preparedness plans and enhanced inter-agency communication. This hazard risk assessment tool is a simple aid in vulnerability assessment, essential for disaster preparedness and response, and may be applied broadly to future international events.

RNA Interference Therapies for an HIV-1 Functional Cure.

PubMed

Scarborough, Robert J; Gatignol, Anne

2017-12-27

HIV-1 drug therapies can prevent disease progression but cannot eliminate HIV-1 viruses from an infected individual. While there is hope that elimination of HIV-1 can be achieved, several approaches to reach a functional cure (control of HIV-1 replication in the absence of drug therapy) are also under investigation. One of these approaches is the transplant of HIV-1 resistant cells expressing anti-HIV-1 RNAs, proteins or peptides. Small RNAs that use RNA interference pathways to target HIV-1 replication have emerged as competitive candidates for cell transplant therapy and have been included in all gene combinations that have so far entered clinical trials. Here, we review RNA interference pathways in mammalian cells and the design of therapeutic small RNAs that use these pathways to target pathogenic RNA sequences. Studies that have been performed to identify anti-HIV-1 RNA interference therapeutics are also reviewed and perspectives on their use in combination gene therapy to functionally cure HIV-1 infection are provided.

Application of ICP-OES to the determination of CuIn(1-x)Ga(x)Se2 thin films used as absorber materials in solar cell devices.

PubMed

Fernández-Martínez, Rodolfo; Caballero, Raquel; Guillén, Cecilia; Gutiérrez, María Teresa; Rucandio, María Isabel

2005-05-01

CuIn(1-x)Ga(x)Se2 [CIGS; x=Ga/(In+Ga)] thin films are among of the best candidates as absorber materials for solar cell applications. The material quality and main properties of the polycrystalline absorber layer are critically influenced by deviations in the stoichiometry, particularly in the Cu/(In+Ga) atomic ratio. In this work a simple, sensitive and accurate method has been developed for the quantitative determination of these thin films by inductively coupled plasma optical emission spectrometry (ICP-OES). The proposed method involves an acid digestion of the samples to achieve the complete solubilization of CIGS, followed by the analytical determination by ICP-OES. A digestion procedure with 50% HNO3 alone or in the presence of 10% HCl was performed to dissolve those thin films deposited on glass or Mo-coated glass substrates, respectively. Two analytical lines were selected for each element (Cu 324.754 and 327.396 nm, Ga 294.364 and 417.206 nm, In 303.936 and 325.609 nm, Se 196.090 and 203.985 nm, and Mo 202.030 and 379.825 nm) and a study of spectral interferences was performed which showed them to be suitable, since they offered a high sensitivity and no significant inter-element interferences were detected. Detection limits for all elements at the selected lines were found to be appropriate for this kind of application, and the relative standard deviations were lower than 1.5% for all elements with the exception of Se (about 5%). The Cu/(In+Ga) atomic ratios obtained from the application of this method to CIGS thin films were consistent with the study of the structural and morphological properties by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Experimental formation of a fractional vortex in a superconducting bi-layer

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Yamamori, H.; Yanagisawa, T.; Nishio, T.; Arisawa, S.

2018-05-01

We report the experimental formation of a fractional vortex generated by using a thin superconducting bi-layer in the form of a niobium bi-layer, observed as a magnetic flux distribution image taken by a scanning superconducting quantum interference device (SQUID) microscope. Thus, we demonstrated that multi-component superconductivity can be realized by an s-wave conventional superconductor, because, in these superconductors, the magnetic flux is no longer quantized as it is destroyed by the existence of an inter-component phase soliton (i-soliton).

Free-space optics mode-wavelength division multiplexing system using LG modes based on decision feedback equalization

NASA Astrophysics Data System (ADS)

Amphawan, Angela; Ghazi, Alaan; Al-dawoodi, Aras

2017-11-01

A free-space optics mode-wavelength division multiplexing (MWDM) system using Laguerre-Gaussian (LG) modes is designed using decision feedback equalization for controlling mode coupling and combating inter symbol interference so as to increase channel diversity. In this paper, a data rate of 24 Gbps is achieved for a FSO MWDM channel of 2.6 km in length using feedback equalization. Simulation results show significant improvement in eye diagrams and bit-error rates before and after decision feedback equalization.

COLLABORATIVE RESEARCH AND DEVELOPMENT (CR&D) Delivery Order 0068: Anti-fretting Coatings Research and Development

DTIC Science & Technology

2008-02-01

reduction in fatigue strength [10]. One common mitigation strategy to the fretting wear/fatigue problem in titanium alloy compressor blades is to...inter-metallic fretting wear between Ti6Al4V ( Titanium , 6% Aluminum, 4% Vanadium) and cold-sprayed, commercially pure nickel coatings. The results...fretting in an aircraft turbine engine is in the compressor section at the blade /disk interface. The blade /disk interface, also known as the

Interference of daratumumab with pretransfusion testing, mimicking a high-titer, low avidity like antibody.

PubMed

Lin, Mei-Hwa; Liu, Fei-Yun; Wang, Hsiu-Mien; Cho, Hsin-Ching; Lo, Shyh-Chyi

2017-01-01

Daratumumab is a monoclonal immunoglobulin against CD38 and has been approved for treating patients with refractory multiple myeloma. The presence of daratumumab in the sera can interfere with pretransfusion testing due to the weakly expression of CD38 on red cells. The reactivity could be mistaken as autoantibody (if autocontrol is positive) or alloantibody (if autocontrol is negative). We present a case that demonstrates daratumumab could mimic a high titer low avidity (HTLA) alloantibody. A 34-year-old male patient of refractory myeloma was recruited in phase three clinical trial involving daratumumab. Samples were sent to the blood bank for pretransfusion testing. Without knowledge of patient having used daratumumab, we mistook the reactivity in the patient's sera as an HTLA antibody due to the results of negative autocontrol and high titers of antibody activity. Antibody screen showed a panreactive pattern and the reactivity against screening cells was up to a titer of 1: 1240. The reactivity was weaker against cord cells than adult cells, became weaker against ZZAP-treated cells and became negative against DDT-treated cells. A discussion with attending physician finally revealed the reactivity was due to the interference caused by daratumumab. The case demonstrates good communication is essential in performing pretransfusion testing for patients receiving daratumumab and other new biological regimens that can interfere with compatibility test.

Interference of daratumumab with pretransfusion testing, mimicking a high-titer, low avidity like antibody

PubMed Central

Lin, Mei-Hwa; Liu, Fei-Yun; Wang, Hsiu-Mien; Cho, Hsin-Ching; Lo, Shyh-Chyi

2017-01-01

Daratumumab is a monoclonal immunoglobulin against CD38 and has been approved for treating patients with refractory multiple myeloma. The presence of daratumumab in the sera can interfere with pretransfusion testing due to the weakly expression of CD38 on red cells. The reactivity could be mistaken as autoantibody (if autocontrol is positive) or alloantibody (if autocontrol is negative). We present a case that demonstrates daratumumab could mimic a high titer low avidity (HTLA) alloantibody. A 34-year-old male patient of refractory myeloma was recruited in phase three clinical trial involving daratumumab. Samples were sent to the blood bank for pretransfusion testing. Without knowledge of patient having used daratumumab, we mistook the reactivity in the patient's sera as an HTLA antibody due to the results of negative autocontrol and high titers of antibody activity. Antibody screen showed a panreactive pattern and the reactivity against screening cells was up to a titer of 1: 1240. The reactivity was weaker against cord cells than adult cells, became weaker against ZZAP-treated cells and became negative against DDT-treated cells. A discussion with attending physician finally revealed the reactivity was due to the interference caused by daratumumab. The case demonstrates good communication is essential in performing pretransfusion testing for patients receiving daratumumab and other new biological regimens that can interfere with compatibility test. PMID:28970695

Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

NASA Astrophysics Data System (ADS)

Rickly, Pamela; Stevens, Philip S.

2018-01-01

Reactions of the hydroxyl radical (OH) play a central role in the chemistry of the atmosphere, and measurements of its concentration can provide a rigorous test of our understanding of atmospheric oxidation. Several recent studies have shown large discrepancies between measured and modeled OH concentrations in forested areas impacted by emissions of biogenic volatile organic compounds (BVOCs), where modeled concentrations were significantly lower than measurements. A potential reason for some of these discrepancies involves interferences associated with the measurement of OH using the laser-induced fluorescence-fluorescence assay by gas expansion (LIF-FAGE) technique in these environments. In this study, a turbulent flow reactor operating at atmospheric pressure was coupled to a LIF-FAGE cell and the OH signal produced from the ozonolysis of α-pinene, β-pinene, ocimene, isoprene, and 2-methyl-3-buten-2-ol (MBO) was measured. To distinguish between OH produced from the ozonolysis reactions and any OH artifact produced inside the LIF-FAGE cell, an external chemical scrubbing technique was used, allowing for the direct measurement of any interference. An interference under high ozone (between 2 × 1013 and 10 × 1013 cm-3) and BVOC concentrations (between approximately 0.1 × 1012 and 40 × 1012 cm-3) was observed that was not laser generated and was independent of the ozonolysis reaction time. For the ozonolysis of α- and β-pinene, the observed interference accounted for approximately 40 % of the total OH signal, while for the ozonolysis of ocimene the observed interference accounted for approximately 70 % of the total OH signal. Addition of acetic acid to the reactor eliminated the interference, suggesting that the source of the interference in these experiments involved the decomposition of stabilized Criegee intermediates (SCIs) inside the FAGE detection cell. Extrapolation of these measurements to ambient concentrations suggests that these interferences should be below the detection limit of the instrument.

Memory Reactivation Predicts Resistance to Retroactive Interference: Evidence from Multivariate Classification and Pattern Similarity Analyses

PubMed Central

Rugg, Michael D.

2016-01-01

Memory reactivation—the reinstatement of processes and representations engaged when an event is initially experienced—is believed to play an important role in strengthening and updating episodic memory. The present study examines how memory reactivation during a potentially interfering event influences memory for a previously experienced event. Participants underwent fMRI during the encoding phase of an AB/AC interference task in which some words were presented twice in association with two different encoding tasks (AB and AC trials) and other words were presented once (DE trials). The later memory test required retrieval of the encoding tasks associated with each of the study words. Retroactive interference was evident for the AB encoding task and was particularly strong when the AC encoding task was remembered rather than forgotten. We used multivariate classification and pattern similarity analysis (PSA) to measure reactivation of the AB encoding task during AC trials. The results demonstrated that reactivation of generic task information measured with multivariate classification predicted subsequent memory for the AB encoding task regardless of whether interference was strong and weak (trials for which the AC encoding task was remembered or forgotten, respectively). In contrast, reactivation of neural patterns idiosyncratic to a given AB trial measured with PSA only predicted memory when the strength of interference was low. These results suggest that reactivation of features of an initial experience shared across numerous events in the same category, but not features idiosyncratic to a particular event, are important in resisting retroactive interference caused by new learning. SIGNIFICANCE STATEMENT Reactivating a previously encoded memory is believed to provide an opportunity to strengthen the memory, but also to return the memory to a labile state, making it susceptible to interference. However, there is debate as to how memory reactivation elicited by a potentially interfering event influences subsequent retrieval of the memory. The findings of the current study indicate that reactivating features idiosyncratic to a particular experience during interference only influences subsequent memory when interference is relatively weak. Critically, reactivation of generic contextual information predicts subsequent source memory when retroactive interference is either strong and weak. The results indicate that reactivation of generic information about a prior episode mitigates forgetting due to retroactive interference. PMID:27076433

Comparing impacts of climate change and mitigation on global agriculture by 2050

NASA Astrophysics Data System (ADS)

van Meijl, Hans; Havlik, Petr; Lotze-Campen, Hermann; Stehfest, Elke; Witzke, Peter; Pérez Domínguez, Ignacio; Bodirsky, Benjamin Leon; van Dijk, Michiel; Doelman, Jonathan; Fellmann, Thomas; Humpenöder, Florian; Koopman, Jason F. L.; Müller, Christoph; Popp, Alexander; Tabeau, Andrzej; Valin, Hugo; van Zeist, Willem-Jan

2018-06-01

Systematic model inter-comparison helps to narrow discrepancies in the analysis of the future impact of climate change on agricultural production. This paper presents a set of alternative scenarios by five global climate and agro-economic models. Covering integrated assessment (IMAGE), partial equilibrium (CAPRI, GLOBIOM, MAgPIE) and computable general equilibrium (MAGNET) models ensures a good coverage of biophysical and economic agricultural features. These models are harmonized with respect to basic model drivers, to assess the range of potential impacts of climate change on the agricultural sector by 2050. Moreover, they quantify the economic consequences of stringent global emission mitigation efforts, such as non-CO2 emission taxes and land-based mitigation options, to stabilize global warming at 2 °C by the end of the century under different Shared Socioeconomic Pathways. A key contribution of the paper is a vis-à-vis comparison of climate change impacts relative to the impact of mitigation measures. In addition, our scenario design allows assessing the impact of the residual climate change on the mitigation challenge. From a global perspective, the impact of climate change on agricultural production by mid-century is negative but small. A larger negative effect on agricultural production, most pronounced for ruminant meat production, is observed when emission mitigation measures compliant with a 2 °C target are put in place. Our results indicate that a mitigation strategy that embeds residual climate change effects (RCP2.6) has a negative impact on global agricultural production relative to a no-mitigation strategy with stronger climate impacts (RCP6.0). However, this is partially due to the limited impact of the climate change scenarios by 2050. The magnitude of price changes is different amongst models due to methodological differences. Further research to achieve a better harmonization is needed, especially regarding endogenous food and feed demand, including substitution across individual commodities, and endogenous technological change.

Effect of Surface Curvature and Chemistry on Protein Stability, Adsorption and Aggregation

NASA Astrophysics Data System (ADS)

Radhakrishna, Mithun

Enzyme immobilization has been of great industrial importance because of its use in various applications like bio-fuel cells, bio-sensors, drug delivery and bio-catalytic films. Although research on enzyme immobilization dates back to the 1970's, it has been only in the past decade that scientists have started to address the problems involved systematically. Most of the previous works on enzyme immobilization have been retrospective in nature i.e enzymes were immobilized on widely used substrates without a compatibility study between the enzyme and the substrate. Consequently, most of the enzymes lost their activity upon immobilization onto these substrates due to many governing factors like protein-surface and inter-protein interactions. These interactions also play a major role biologically in cell signaling, cell adhesion and inter-protein interactions specifically is believed to be the major cause for neurodegenerative diseases like Alzheimer's and Parkinson's disease. Therefore understanding the role of these forces on proteins is the need of the hour. In my current research, I have mainly focused on two factors a) Surface Curvature b) Surface Chemistry as both of these play a pivotal role in influencing the activity of the enzymes upon immobilization. I study the effect of these factors computationally using a stochastic method known as Monte Carlo simulations. My research work carried out in the frame work of a Hydrophobic-Polar (HP) lattice model for the protein shows that immobilizing enzymes inside moderately hydrophilic or hydrophobic pores results in an enhancement of the enzymatic activity compared to that in the bulk. Our results also indicate that there is an optimal value of surface curvature and hydrophobicity/hydrophilicity where this enhancement of enzymatic activity is highest. Further, our results also show that immobilization of enzymes inside hydrophobic pores of optimal sizes are most effective in mitigating protein-aggregation. These results provide us a rationale to understand the role of chaperonins in protein folding and disaggregation. Our results indicate that strong protein-surface interactions and confinement inducement stability inside pores makes it best suitable for enzyme immobilization.

Relief from glucose interference in microcin B17 biosynthesis by growth in a rotating-wall bioreactor

NASA Technical Reports Server (NTRS)

Fang, A.; Pierson, D. L.; Mishra, S. K.; Demain, A. L.; Peirson, D. L. (Principal Investigator)

2000-01-01

Glucose interference in production of microcin B17 by Escherichia coli ZK650 was decreased sevenfold by growth in a ground-based rotating-wall bioreactor operated in the simulated microgravity mode as compared with growth in flasks. When cells were grown in the bioreactor in the normal gravity mode, relief from glucose interference was even more dramatic, amounting to a decrease in glucose interference of over 100-fold.

Evaluating System Parameters on a Dragonfly using Simulation and Visualization

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

Bhatele, Abhinav; Jain, Nikhil; Livnat, Yarden

The dragon y topology is becoming a popular choice for build- ing high-radix, low-diameter networks with high-bandwidth links. Even with a powerful network, preliminary experi- ments on Edison at NERSC have shown that for communica- tion heavy applications, job interference and thus presumably job placement remains an important factor. In this paper, we explore the e ects of job placement, job sizes, parallel workloads and network con gurations on network through- put to better understand inter-job interference. We use a simulation tool called Damsel y to model the network be- havior of Edison and study the impact of various systemmore » parameters on network throughput. Parallel workloads based on ve representative communication patters are used and the simulation studies on up to 131,072 cores are aided by a new visualization of the dragon y network.« less

Barrier Effects in Non-retinotopic Feature Attribution

PubMed Central

Aydin, Murat; Herzog, Michael H.; Öğmen, Haluk

2011-01-01

When objects move in the environment, their retinal images can undergo drastic changes and features of different objects can be inter-mixed in the retinal image. Notwithstanding these changes and ambiguities, the visual system is capable of establishing correctly feature-object relationships as well as maintaining individual identities of objects through space and time. Recently, by using a Ternus-Pikler display, we have shown that perceived motion correspondences serve as the medium for non-retinotopic attribution of features to objects. The purpose of the work reported in this manuscript was to assess whether perceived motion correspondences provide a sufficient condition for feature attribution. Our results show that the introduction of a static “barrier” stimulus can interfere with the feature attribution process. Our results also indicate that the barrier stops feature attribution based on interferences related to the feature attribution process itself rather than on mechanisms related to perceived motion. PMID:21767561

International round-robin inter-comparison of dye-sensitized and crystalline silicon solar cells

NASA Astrophysics Data System (ADS)

Chen, Chia-Yuan; Ahn, Seung Kyu; Aoki, Dasiuke; Kokubo, Junichi; Yoon, Kyung Hoon; Saito, Hidenori; Lee, Kyung Sik; Magaino, Shinichi; Takagi, Katsuhiko; Lin, Ling-Chuan; Lee, Kun-Mu; Wu, Chun-Guey; Zhou, Hong; Igari, Sanekazu

2017-02-01

An international round-robin inter-comparison of the spectral responsivity (SR) and current-voltage (I-V) characteristics for dye-sensitized solar cells (DSCs) and crystalline silicon solar cells is reported for the first time. The crystalline silicon cells with various spectral responsivities were also calibrated by AIST to validate this round-robin activity. On the basis of the remarkable consistency in Pmax (within ±1.4% among participants) and Isc (within ±1.2% compared to the primary calibration of AIST) of the silicon specimens, the discrepancy in the SR and photovoltaic parameters of five DSCs among three national laboratories can be verified and diagnosed. Recommendations about sample packages, SR and I-V measurement methods as well as the inter-comparison protocol for improving the performance characterization of the mesoscopic DSCs are presented according to the consolidated data and the experience of the participants.

PI3K and Bcl-2 inhibition primes glioblastoma cells to apoptosis through downregulation of Mcl-1 and Phospho-BAD.

PubMed

Pareja, Fresia; Macleod, David; Shu, Chang; Crary, John F; Canoll, Peter D; Ross, Alonzo H; Siegelin, Markus D

2014-07-01

Glioblastoma multiforme (GBM) is a highly malignant human brain neoplasm with limited therapeutic options. GBMs display a deregulated apoptotic pathway with high levels of the antiapoptotic Bcl-2 family of proteins and overt activity of the phosphatidylinositol 3-kinase (PI3K) signaling pathway. Therefore, combined interference of the PI3K pathway and the Bcl-2 family of proteins is a reasonable therapeutic strategy. ABT-263 (Navitoclax), an orally available small-molecule Bcl-2 inhibitor, and GDC-0941, a PI3K inhibitor, were used to treat established glioblastoma and glioblastoma neurosphere cells, alone or in combination. Although GDC-0941 alone had a modest effect on cell viability, treatment with ABT-263 displayed a marked reduction of cell viability and induction of apoptotic cell death. Moreover, combinatorial therapy using ABT-263 and GDC-0941 showed an enhanced effect, with a further decrease in cellular viability. Furthermore, combination treatment abrogated the ability of stem cell-like glioma cells to form neurospheres. ABT-263 and GDC-0941, in combination, resulted in a consistent and significant increase of Annexin V positive cells and loss of mitochondrial membrane potential compared with either monotherapy. The combination treatment led to enhanced cleavage of both initiator and effector caspases. Mechanistically, GDC-0941 depleted pAKT (Serine 473) levels and suppressed Mcl-1 protein levels, lowering the threshold for the cytotoxic actions of ABT-263. GDC-0941 decreased Mcl-1 in a posttranslational manner and significantly decreased the half-life of Mcl-1 protein. Ectopic expression of human Mcl-1 mitigated apoptotic cell death induced by the drug combination. Furthermore, GDC-0941 modulated the phosphorylation status of BAD, thereby further enhancing ABT-263-mediated cell death. Combination therapy with ABT-263 and GDC-0941 has novel therapeutic potential by specifically targeting aberrantly active, deregulated pathways in GBM, overcoming endogenous resistance to apoptosis. ©2014 American Association for Cancer Research.

Recent improvements of the JET lithium beam diagnostica)

NASA Astrophysics Data System (ADS)

Brix, M.; Dodt, D.; Dunai, D.; Lupelli, I.; Marsen, S.; Melson, T. F.; Meszaros, B.; Morgan, P.; Petravich, G.; Refy, D. I.; Silva, C.; Stamp, M.; Szabolics, T.; Zastrow, K.-D.; Zoletnik, S.; JET-EFDA Contributors

2012-10-01

A 60 kV neutral lithium diagnostic beam probes the edge plasma of JET for the measurement of electron density profiles. This paper describes recent enhancements of the diagnostic setup, new procedures for calibration and protection measures for the lithium ion gun during massive gas puffs for disruption mitigation. New light splitting optics allow in parallel beam emission measurements with a new double entrance slit CCD spectrometer (spectrally resolved) and a new interference filter avalanche photodiode camera (fast density and fluctuation studies).

Technical Solution for Mitigating Radio-Frequency (RF) Interference to Air Traffic Control Communications

DTIC Science & Technology

2013-09-01

the fiber-optic receiver. When electrical power was restored by reinserting the plug, there could be no guarantee that all of the relays within the...useable set of coded instructions was expected to take approximately 3 man-months to develop and would incur costs, in labor , much greater than the...man-hour labor load was expected to be only about a month, the inability to quickly verify a “final” circuit design represented the highest risk

Magnetic resonance imaging following InterStim®: an institutional experience with imaging safety and patient satisfaction.

PubMed

Chermansky, Christopher J; Krlin, Ryan M; Holley, Thomas D; Woo, Howard H; Winters, J Christian

2011-11-01

We retrospectively assessed patient safety and satisfaction after magnetic resonance imaging (MRI) in patients with an InterStim® unit. The records of all patients implanted with InterStim® between 1998 and 2006 were reviewed. Nine of these patients underwent MRI following InterStim® implantation. The patients' neurologists requested the MRI exams for medical reasons. Both 0.6  Tesla (T) and 1.5  T machines were used. Patient safety, interference of implanted pulse generator (IPG) with radiological interpretation, and patient satisfaction were assessed in these patients. The first patient in the series had IPG failure following MRI. For this patient, the voltage amplitude was set to zero, the IPG was turned off, and the IPG magnetic switch was left on. The patient underwent MRI uneventfully; however, the IPG did not function upon reprogramming. The IPG magnetic switch was turned off for the eight subsequent patients, all of whom underwent MRI safely. In addition, all of their IPGs functioned appropriately following reprogramming. Of the 15 MRIs performed, the lumbar spine was imaged in eight studies, the pelvis was imaged in one study, and the remaining examinations involved imaging the brain or cervical spine. Neither the IPG nor the sacral leads interfered with MRI interpretation. None of the eight patients perceived a change in perception or satisfaction following MRI. Although we don't advocate the routine use of MRI following InterStim® implantation, our experience suggests MRI may be feasible under controlled conditions and without adverse events. Copyright © 2011 Wiley Periodicals, Inc.

The ng_ζ1 toxin of the gonococcal epsilon/zeta toxin/antitoxin system drains precursors for cell wall synthesis.

PubMed

Rocker, Andrea; Peschke, Madeleine; Kittilä, Tiia; Sakson, Roman; Brieke, Clara; Meinhart, Anton

2018-04-27

Bacterial toxin-antitoxin complexes are emerging as key players modulating bacterial physiology as activation of toxins induces stasis or programmed cell death by interference with vital cellular processes. Zeta toxins, which are prevalent in many bacterial genomes, were shown to interfere with cell wall formation by perturbing peptidoglycan synthesis in Gram-positive bacteria. Here, we characterize the epsilon/zeta toxin-antitoxin (TA) homologue from the Gram-negative pathogen Neisseria gonorrhoeae termed ng_ɛ1 / ng_ζ1. Contrary to previously studied streptococcal epsilon/zeta TA systems, ng_ɛ1 has an epsilon-unrelated fold and ng_ζ1 displays broader substrate specificity and phosphorylates multiple UDP-activated sugars that are precursors of peptidoglycan and lipopolysaccharide synthesis. Moreover, the phosphorylation site is different from the streptococcal zeta toxins, resulting in a different interference with cell wall synthesis. This difference most likely reflects adaptation to the individual cell wall composition of Gram-negative and Gram-positive organisms but also the distinct involvement of cell wall components in virulence.

Silencing the hsp25 Gene Eliminates Migration Capability of the Highly Metastatic Murine 4T1 Breast Adenocarcinoma Cell

PubMed Central

Bausero, Maria A.; Bharti, Ajit; Page, Diana T.; Perez, Kristen D.; Eng, Jason W.-L.; Ordonez, Susana L.; Jantschitsch, Christian; Kindas-Muegge, Ingela; Ciocca, Daniel; Asea, Alexzander

2006-01-01

The 25-kDa heat shock protein (Hsp25) is associated with various malignancies and is expressed at high levels in biopsies as well as circulating in the serum of breast cancer patients. In this study, we used RNA interference technology to silence the hsp25 gene in 4T1 breast adenocarcinoma cells, known as a poorly immunogenic, highly metastatic cell line. We demonstrate that transfection of 4T1 cells with short interference RNA-Hsp25 dramatically inhibits proliferation as compared with control transfected cells. In addition, we show that 4T1 cells transfected with short interference RNA-Hsp25 abrogates tumor migration potential by a mechanism that is in part due to the repression of matrix metalloproteinase 9 expression and a concomitant upregulation of its antagonist, tissue inhibitor metalloproteinase 1. Taken together, these findings provide a model system for the study of metastatic potential of tumors and are suggestive of an earlier unrecognized role for Hsp25 in tumor migration. PMID:16340246

Silencing the hsp25 gene eliminates migration capability of the highly metastatic murine 4T1 breast adenocarcinoma cell.

PubMed

Bausero, Maria A; Bharti, Ajit; Page, Diana T; Perez, Kristen D; Eng, Jason W-L; Ordonez, Susana L; Asea, Edwina E; Jantschitsch, Christian; Kindas-Muegge, Ingela; Ciocca, Daniel; Asea, Alexzander

2006-01-01

The 25-kDa heat shock protein (Hsp25) is associated with various malignancies and is expressed at high levels in biopsies as well as circulating in the serum of breast cancer patients. In this study, we used RNA interference technology to silence the hsp25 gene in 4T1 breast adenocarcinoma cells, known as a poorly immunogenic, highly metastatic cell line. We demonstrate that transfection of 4T1 cells with short interference RNA-Hsp25 dramatically inhibits proliferation as compared with control transfected cells. In addition, we show that 4T1 cells transfected with short interference RNA-Hsp25 abrogates tumor migration potential by a mechanism that is in part due to the repression of matrix metalloproteinase 9 expression and a concomitant upregulation of its antagonist, tissue inhibitor metalloproteinase 1. Taken together, these findings provide a model system for the study of metastatic potential of tumors and are suggestive of an earlier unrecognized role for Hsp25 in tumor migration. Copyright 2006 S. Karger AG, Basel.

Measurement of TFF3 mRNA in aspirates from thyroid nodules using mesh filtration: the first clinical trial in 130 cases.

PubMed

Yamada, Hiroya; Takano, Toru; Kihara, Minoru; Hirokawa, Mitsuyoshi; Yoshida, Hiroshi; Watanabe, Mikio; Iwatani, Yoshinori; Hidaka, Yoh; Miyauchi, Akira

2012-01-01

Measurement of gene expression levels in thyroid tumor cells in aspirates was difficult because it is interfered with peripheral blood cells or infiltrating lymphocytes. In this study, we established a novel method to separate thyroid tumor cells from blood cells efficiently with mesh filtration. The expression level of trefoil factor 3 (TFF3) mRNA was estimated using LGALS3 mRNA as an internal control (T/G ratio) in 148 preoperative thyroid aspirates. Intra-assay coefficients of variation (CV) of T/G ratio for high, moderate, and low samples were 6.5%, 2.5%, and 9.7%, respectively, and inter-assay CV for high, moderate, and low samples were 27.7%, 21.9%, and 38.2%, respectively. Nondiagnostic samples in terms of T/G ratio and cytology were 12.2% and 16.9%, respectively. We observed no interference with the data by contaminating blood cells. Among these patients, 12 patients received more than two repeated aspirations. We did not observe a marked day-to-day variation except in two cases. All 13 preoperative aspirates diagnosed as malignant by cytology showed an extremely low T/G ratio, whereas 93 aspirates diagnosed as benign by cytology showed extremely varied T/G ratios and 21.5% of them showed a T/G ratio below the cut-off value. Eleven cases underwent surgery. All nodules showing a low T/G ratio were diagnosed as papillary carcinoma by pathological diagnosis. However, one nodule diagnosed as follicular adenoma after surgery showed a high T/G ratio. Our present method may be a promising preoperative test for measuring mRNAs in thyroid aspirates.

Maternal T-Cell Engraftment Interferes With Human Leukocyte Antigen Typing in Severe Combined Immunodeficiency.

PubMed

Liu, Chang; Duffy, Brian; Bednarski, Jeffrey J; Calhoun, Cecelia; Lay, Lindsay; Rundblad, Barrett; Payton, Jacqueline E; Mohanakumar, Thalachallour

2016-02-01

To report the laboratory investigation of a case of severe combined immunodeficiency (SCID) with maternal T-cell engraftment, focusing on the interference of human leukocyte antigen (HLA) typing by blood chimerism. HLA typing was performed with three different methods, including sequence-specific primer (SSP), sequence-specific oligonucleotide, and Sanger sequencing on peripheral blood leukocytes and buccal cells, from a 3-month-old boy and peripheral blood leukocytes from his parents. Short tandem repeat (STR) testing was performed in parallel. HLA typing of the patient's peripheral blood leukocytes using the SSP method demonstrated three different alleles for each of the HLA-B and HLA-C loci, with both maternal alleles present at each locus. Typing results from the patient's buccal cells showed a normal pattern of inheritance for paternal and maternal haplotypes. STR enrichment testing of the patient's CD3+ T lymphocytes and CD15+ myeloid cells confirmed maternal T-cell engraftment, while the myeloid cell profile matched the patient's buccal cells. Maternal T-cell engraftment may interfere with HLA typing in patients with SCID. Selection of the appropriate typing methods and specimens is critical for accurate HLA typing and immunologic assessment before allogeneic hematopoietic stem cell transplantation. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Age and CD161 Expression Contribute to Inter-Individual Variation in Interleukin-23 Response in CD8+ Memory Human T Cells

PubMed Central

Abraham, Clara; Cho, Judy H.

2013-01-01

The interleukin-23 (IL-23) pathway plays a critical role in the pathogenesis of multiple chronic inflammatory disorders, however, inter-individual variability in IL-23-induced signal transduction in circulating human lymphocytes has not been well-defined. In this study, we observed marked, reproducible inter-individual differences in IL-23 responsiveness (measured by STAT3 phosphorylation) in peripheral blood CD8+CD45RO+ memory T and CD3+CD56+ NKT cells. Age, but not gender, was a significant (Pearson’s correlation coefficient, r = −0.37, p = 0.001) source of variability observed in CD8+CD45RO+ memory T cells, with IL-23 responsiveness gradually decreasing with increasing age. Relative to cells from individuals demonstrating low responsiveness to IL-23 stimulation, CD8+CD45RO+ memory T cells from individuals demonstrating high responsiveness to IL-23 stimulation showed increased gene expression for IL-23 receptor (IL-23R), RORC (RORγt) and CD161 (KLRB1), whereas RORA (RORα) and STAT3 expression were equivalent. Similar to CD4+ memory T cells, IL-23 responsiveness is confined to the CD161+ subset in CD8+CD45RO+ memory T cells, suggesting a similar CD161+ precursor as has been reported for CD4+ Th17 cells. We observed a very strong positive correlation between IL-23 responsiveness and the fraction of CD161+, CD8+CD45RO+ memory T cells (r = 0.80, p<0.001). Moreover, the fraction of CD161+, CD8+CD45RO+ memory T cells gradually decreases with aging (r = −0.34, p = 0.05). Our data define the inter-individual differences in IL-23 responsiveness in peripheral blood lymphocytes from the general population. Variable expression of CD161, IL-23R and RORC affects IL-23 responsiveness and contributes to the inter-individual susceptibility to IL-23-mediated defenses and inflammatory processes. PMID:23469228

CRISPR interference: RNA-directed adaptive immunity in bacteria and archaea

PubMed Central

Marraffini, Luciano A.; Sontheimer, Erik J.

2010-01-01

Sequence-directed genetic interference pathways control gene expression and preserve genome integrity in all kingdoms of life. The importance of such pathways is highlighted by the extensive study of RNA interference (RNAi) and related processes in eukaryotes. In many bacteria and most archaea, clustered, regularly interspaced short palindromic repeats (CRISPRs) are involved in a more recently discovered interference pathway that protects cells from bacteriophages and conjugative plasmids. CRISPR sequences provide an adaptive, heritable record of past infections and express CRISPR RNAs — small RNAs that target invasive nucleic acids. Here, we review the mechanisms of CRISPR interference and its roles in microbial physiology and evolution. We also discuss potential applications of this novel interference pathway. PMID:20125085

High Precision NO2 and NO measurements with the ICAD instrument during s-b-s campaign Hohenpeißenberg 2016

NASA Astrophysics Data System (ADS)

Pöhler, Denis; Lutz, Erik; Horbanski, Martin; Lampel, Johannes; Platt, Ulrich

2017-04-01

Nitrogen Oxides (NOx = NO2 + NO) play a major role in air pollution and atmospheric chemistry. Beside health effects they influence e.g. acid rain, ozone and oxidation capacity. But precise NO2 and NO measurements are still difficult. State of the art NO2 / NO instruments show significant interferences e.g. to H2O and HONO, problems of zero point and calibration drifts, temperature and also vibration influences. Other systems, especially low cost sensors, feature significant problems in terms of measurement accuracy and reliability. To overcome these problems we developed a direct spectroscopic NO2 / NOx ICAD instrument (Iterative Cavity Enhanced DOAS). It feature high accuracy, is relatively small, mobile and requires only low power consumption. During a side by side (s-b-s) inter-comparison campaign at the Meteorological Observatory Hohenpeißenberg (DWD) 2016 the performance of different instruments for NO2, NO and NOx were investigated under natural and artificial conditions. The concentration ranged from few ppt up to 100ppb. The inter-comparison demonstrates excellent performance of our ICAD in terms of accuracy and drift. In comparison to other techniques it features no interferences to different humidity's, temperatures and interfering gases. Also the zero point and calibration is absolutely stable. As the instrument is also much simpler and easier to operate, it has many advantages in comparison to other instruments. The characteristics of the instruments and results of the campaign will be presented.

NASA-FAA-NOAA Partnering Strategy

NASA Technical Reports Server (NTRS)

Colantonio, Ron

2003-01-01

This viewgraph presentation provides an overview of NASA-FAA (Federal Aviation Administration) and NOAA (National Oceanic and Atmospheric Administration) collaboration efforts particularly in the area of aviation and aircraft safety. Five technology areas are being jointly by these agencies: (1) aviation weather information; (2) weather products; (3) automet technologies; (4) forward looking weather sensors and (5) turbulence controls and mitigation systems. Memorandum of Agreements (MOU) between these agencies are reviewed. A general review of the pros and pitfalls of inter-agency collaborations is also presented.

Emergence and migration of trunk neural crest cells in a snake, the California Kingsnake (Lampropeltis getula californiae)

PubMed Central

2010-01-01

Background The neural crest is a group of multipotent cells that emerges after an epithelial-to-mesenchymal transition from the dorsal neural tube early during development. These cells then migrate throughout the embryo, giving rise to a wide variety derivatives including the peripheral nervous system, craniofacial skeleton, pigment cells, and endocrine organs. While much is known about neural crest cells in mammals, birds, amphibians and fish, relatively little is known about their development in non-avian reptiles like snakes and lizards. Results In this study, we show for the first time ever trunk neural crest migration in a snake by labeling it with DiI and immunofluorescence. As in birds and mammals, we find that early migrating trunk neural crest cells use both a ventromedial pathway and an inter-somitic pathway in the snake. However, unlike birds and mammals, we also observed large numbers of late migrating neural crest cells utilizing the inter-somitic pathway in snake. Conclusions We found that while trunk neural crest migration in snakes is very similar to that of other amniotes, the inter-somitic pathway is used more extensively by late-migrating trunk neural crest cells in snake. PMID:20482793

Emergence and migration of trunk neural crest cells in a snake, the California Kingsnake (Lampropeltis getula californiae).

PubMed

Reyes, Michelle; Zandberg, Katrina; Desmawati, Iska; de Bellard, Maria E

2010-05-18

The neural crest is a group of multipotent cells that emerges after an epithelial-to-mesenchymal transition from the dorsal neural tube early during development. These cells then migrate throughout the embryo, giving rise to a wide variety derivatives including the peripheral nervous system, craniofacial skeleton, pigment cells, and endocrine organs. While much is known about neural crest cells in mammals, birds, amphibians and fish, relatively little is known about their development in non-avian reptiles like snakes and lizards. In this study, we show for the first time ever trunk neural crest migration in a snake by labeling it with DiI and immunofluorescence. As in birds and mammals, we find that early migrating trunk neural crest cells use both a ventromedial pathway and an inter-somitic pathway in the snake. However, unlike birds and mammals, we also observed large numbers of late migrating neural crest cells utilizing the inter-somitic pathway in snake. We found that while trunk neural crest migration in snakes is very similar to that of other amniotes, the inter-somitic pathway is used more extensively by late-migrating trunk neural crest cells in snake.

[Mechanism of protective effects of tumor necrosis factor receptor associated protein 1 on hypoxic cardiomyocytes of rats].

PubMed

Xiang, F; Zhang, D X; Ma, S Y; Huang, Y S

2016-12-20

Objective: To investigate the mechanism of protective effects of tumor necrosis factor receptor associated protein 1 (TRAP1) on hypoxic cardiomyocytes of rats. Methods: Primary cultured cardiomyocytes were obtained from neonatal Sprague-Dawley rats (aged 1 to 3 days) and then used in the following experiments. (1) Cells were divided into group TRAP1 and control group according to the random number table (the same grouping method below), and then the total protein of cells was extracted. Total protein of cells in group TRAP1 was added with mouse anti-rat TRAP1 monoclonal antibody, while that in control group was added with the same type of IgG from mouse. Co-immunoprecipitation and protein mass spectrography analysis were used to determine the possible proteins interacted with TRAP1. (2) Cells were divided into normoxia blank control group (NBC), normoxia+ TRAP1 interference control group (NTIC), normoxia+ TRAP1 interference group (NTI), normoxia+ TRAP1 over-expression control group (NTOC), and normoxia+ TRAP1 over-expression group (NTO), with 1 well in each group. Cells in group NBC were routinely cultured, while cells in the latter four groups were respectively added with TRAP1 RNA interference empty virus vector, TRAP1 RNA interference adenovirus vector, TRAP1 over-expression empty virus vector, and TRAP1 over-expression adenovirus vector. Another batch of cells were divided into group NBC, hypoxic blank control group (HBC), hypoxic+ TRAP1 interference control group (HTIC), hypoxic+ TRAP1 interference group (HTI), hypoxic+ TRAP1 over-expression control group (HTOC), and hypoxic+ TRAP1 over-expression group (HTO), with 1 well in each group. Cells in hypoxic groups were under hypoxic condition for 6 hours after being treated as those in the corresponding normoxia groups, respectively. The mRNA expression of cytochrome c oxidase subunit Ⅱ (COXⅡ) of cells in each group was detected by real time fluorescent quantitive reverse transcription polymerase chain reaction. Experiments were repeated for three times. (3) Cells were divided into group NBC, group HBC, group HTOC, group HTO, hypoxic+ TRAP1 over-expression+ COXⅡinterference control group (HTOCIC), and hypoxic+ TRAP1 over-expression+ COXⅡinterference group (HTOCI), with 3 wells in each group. Cells in the previous 4 groups were treated as those in experiment (2). Cells in group HTOCIC and HTOCI were respectively transfected with COXⅡ RNA interference empty virus vector and COXⅡ RNA interference adenovirus vector, and then both added with TRAP1 over-expression adenovirus vector. The proliferation activity of cells was determined by cell counting kit 8 and microplate reader, and the ratio of death cells was measured by propidium lodide and Hoechst 33342 staining. Another batch of cells were divided into group NBC, group HBC, group HTIC, group HTI, hypoxic+ TRAP1 interference+ COXⅡover-expression control group (HTICOC), and hypoxic+ TRAP1 interference+ COXⅡ over-expression group (HTICO), with 3 wells in each group. Cells in the previous 4 groups were treated as those in experiment (2). Cells in group HTICOC and HTICO were both transfected with TRAP1 RNA interference adenovirus vector, and then respectively added with COXⅡ over-expression empty virus vector and COXⅡ over-expression adenovirus vector. The proliferation activity of cells and the ratio of death cells were detected as before. Experiments were repeated for three times. Data were processed with one-way analysis of variance and LSD test. Results: (1) The expression of TRAP1 was found in cells of group TRAP1, while that was not found in cells of control group. The possible proteins interacted with TRAP1 were keratin, COXⅡ, and an unknown protein with predicted molecular weight 13×10 3 . (2) Compared with that in group NBC, the mRNA expression of COXⅡof cells had no significant change in group NTIC and group NTOC (with P values above 0.05), but significantly decreased in group NTI ( P <0.01), and significantly increased in group NTO ( P <0.01). Compared with that in group NBC, the mRNA expression of COXⅡof cells in group HBC was significantly decreased ( P <0.01). Compared with that in group HBC, the mRNA expression of COXⅡof cells had no significant change in group HTIC and group HTOC (with P values above 0.05), but significantly decreased in group HTI ( P <0.01), and significantly increased in group HTO ( P <0.01). (3) The proliferation activity of cells in group NBC, group HBC, group HTOC, group HTO, group HTOCIC, and group HTOCI was respectively 0.498±0.022, 0.303±0.018, 0.313±0.032, 0.456±0.031, 0.448±0.034, and 0.335±0.026, and the ratios of death cells in above groups were respectively (4.7±1.5)%, (24.7±3.1)%, (26.0±2.7)%, (13.3±2.5)%, (12.7±2.1)%, and (21.0±1.7)%. Compared with those in group NBC, the proliferation activity of cells in HBC was decreased, while the ratio of death cells was increased (with P values below 0.01). Compared with those in group HBC, the proliferation activity of cells and the ratio of death cells in group HTOC had no significant change (with P values above 0.05), while the proliferation activity of cells was increased and the ratio of death cells was decreased in group HTO (with P values below 0.01). Compared with those in group HTO, the proliferation activity of cells and the ratio of death cells in group HTOCIC had no significant change (with P values above 0.05), while the proliferation activity of cells was decreased and the ratio of death cells was increased in group HTOCI (with P values below 0.01). (4) The proliferation activity of cells in group NBC, group HBC, group HTIC, group HTI, group HTICOC, and group HTICO was respectively 0.444±0.025, 0.275±0.016, 0.283±0.021, 0.150±0.009, 0.135±0.011, and 0.237±0.017, and the ratios of death cells in above groups were respectively (3.7±0.6)%, (21.0±2.7)%, (20.3±3.1)%, (31.7±2.5)%, (33.3±3.2)%, and (19.3±1.5)%. Compared with those in group HBC, the proliferation activity of cells and the ratio of death cells in group HTIC had no significant change (with P values above 0.05). Compared with those in group HBC and group HTIC, the proliferation activity of cells was decreased and the ratio of death cells was significantly increased in group HTI (with P values below 0.01). Compared with those in group HTI, the proliferation activity of cells and the ratio of death cells in group HTICOC had no significant change (with P values above 0.05), while the proliferation activity of cells was increased and the ratio of death cells was significantly decreased in group HTICO (with P values below 0.01). Conclusions: TRAP1 can up-regulate the expression of COXⅡ mRNA, and COXⅡ is one of the downstream effector molecules that TRAP1 mediates its protective effects on hypoxic cardiomyocytes.

The detailed characteristics of positive corona current pulses in the line-to-plane electrodes

NASA Astrophysics Data System (ADS)

Xuebao, LI; Dayong, LI; Qian, ZHANG; Yinfei, LI; Xiang, CUI; Tiebing, LU

2018-05-01

The corona current pulses generated by corona discharge are the sources of the radio interference from transmission lines and the detailed characteristics of the corona current pulses from conductor should be investigated in order to reveal their generation mechanism. In this paper, the line-to-plane electrodes are designed to measure and analyze the characteristics of corona current pulses from positive corona discharges. The influences of inter-electrode gap and line diameters on the detail characteristics of corona current pulses, such as pulse amplitude, rise time, duration time and repetition frequency, are carefully analyzed. The obtained results show that the pulse amplitude and the repetition frequency increase with the diameter of line electrode when the electric fields on the surface of line electrodes are same. With the increase of inter-electrode gap, the pulse amplitude and the repetition frequency first decrease and then turn to be stable, while the rise time first increases and finally turns to be stable. The distributions of electric field and space charges under the line electrodes are calculated, and the influences of inter-electrode gap and line electrode diameter on the experimental results are qualitatively explained.

Improved Calibration through SMAP RFI Change Detection

NASA Technical Reports Server (NTRS)

Piepmeier, Jeffrey; De Amici, Giovanni; Mohammed, Priscilla; Peng, Jinzheng

2017-01-01

Anthropogenic Radio-Frequency Interference (RFI) drove both the SMAP (Soil Moisture Active Passive) microwave radiometer hardware and Level 1 science algorithm designs to use new technology and techniques for the first time on a spaceflight project. Care was taken to provide special features allowing the detection and removal of harmful interference in order to meet the error budget. Nonetheless, the project accepted a risk that RFI and its mitigation would exceed the 1.3-K error budget. Thus, RFI will likely remain a challenge afterwards due to its changing and uncertain nature. To address the challenge, we seek to answer the following questions: How does RFI evolve over the SMAP lifetime? What calibration error does the changing RFI environment cause? Can time series information be exploited to reduce these errors and improve calibration for all science products reliant upon SMAP radiometer data? In this talk, we address the first question.

Effects of nutrient enrichment on Prymnesium parvum population dynamics and toxicity: Results from field experiments, Lake Possum Kingdom, USA

USGS Publications Warehouse

Roelke, D.L.; Errera, R.M.; Riesling, R.; Brooks, B.W.; Grover, J.P.; Schwierzke, L.; Urena-Boeck, F.; Baker, J.; Pinckney, J.L.

2007-01-01

Large fish kills associated with toxic populations of the haptophyte Prymnesium parvum occur worldwide. In the past 5 yr, incidences of P. parvum blooms in inland water bodies of Texas (USA) have increased dramatically, where cell densities in excess of 1 ?? 107 cells l-1 are typically observed. We conducted field experiments (Lake Possum Kingdom) during the fall and early spring of 28 d duration using 24 enclosures of 1.57 m 3 each. The experiments investigated the effect of nutrient enrichment, immigration of P. parvum and addition of barley straw extract on phytoplankton biomass and assemblage structure, P. parvum population density, zooplankton biomass and assemblage structure, bacteria, and toxicity. Nutrient enrichment stimulated P. parvum population growth beyond bloom proportions (>1 ?? 107 cells l-1). However, P. parvum did not dominate the assemblage under these conditions, as it does during natural blooms. Instead, euglenophytes and chlorophytes dominated. Toxicity, estimated using fish (Pimephales promelas) and cladoceran (Daphnia magna) bioassays and which is linked to P. parvum's allelopathic and mixotrophic effectiveness, was greatly reduced (eliminated in many cases) under conditions of nutrient enrichment. The suppression of toxicity by nutrient addition suggested that targeted and time-limited nutrient manipulations might be used to mitigate the effects of P. parvum blooms. Immigration of P. parvum into natural assemblages and addition of barley straw extract had no significant effect on plankton dynamics. ?? Inter-Research 2007.

Sensitive Detection of the Natural Killer Cell-Mediated Cytotoxicity of Anti-CD20 Antibodies and Its Impairment by B-Cell Receptor Pathway Inhibitors

PubMed Central

Knödgen, Eva; Göckeritz, Elisa; Vondey, Verena; Neumann, Lars; Herter, Sylvia; Klein, Christian; Hallek, Michael

2018-01-01

The antibody-dependent cell-mediated cytotoxicity (ADCC) of the anti-CD20 monoclonal antibodies (mAbs) rituximab and obinutuzumab against the cell line Raji and isolated CLL cells and its potential impairment by kinase inhibitors (KI) was determined via lactate dehydrogenase release or calcein retention, respectively, using genetically modified NK92 cells expressing CD16-176V as effector cells. Compared to peripheral blood mononuclear cells, recombinant effector cell lines showed substantial alloreactivity-related cytotoxicity without addition of mAbs but afforded determination of ADCC with reduced interassay variability. The cytotoxicity owing to alloreactivity was less susceptible to interference by KI than the ADCC of anti-CD20 mAbs, which was markedly diminished by ibrutinib, but not by idelalisib. Compared to rituximab, the ADCC of obinutuzumab against primary CLL cells showed approximately 30% higher efficacy and less interference with KI. Irreversible BTK inhibitors at a clinically relevant concentration of 1 μM only weakly impaired the ADCC of anti-CD20 mAbs, with less influence in combinations with obinutuzumab than with rituximab and by acalabrutinib than by ibrutinib or tirabrutinib. In summary, NK cell line-based assays permitted the sensitive detection of ADCC of therapeutic anti-CD20 mAbs against CLL cells and of the interference of KI with this important killing mechanism. PMID:29750146

Electrochemical cell structure including an ionomeric barrier

DOEpatents

Lambert, Timothy N.; Hibbs, Michael

2017-06-20

An apparatus includes an electrochemical half-cell comprising: an electrolyte, an anode; and an ionomeric barrier positioned between the electrolyte and the anode. The anode may comprise a multi-electron vanadium phosphorous alloy, such as VP.sub.x, wherein x is 1-5. The electrochemical half-cell is configured to oxidize the vanadium and phosphorous alloy to release electrons. A method of mitigating corrosion in an electrochemical cell includes disposing an ionomeric barrier in a path of electrolyte or ion flow to an anode and mitigating anion accumulation on the surface of the anode.

Electrostatic Charging of the Pathfinder Rover

NASA Technical Reports Server (NTRS)

Siebert, Mark W.; Kolecki, Joseph C.

1996-01-01

The Mars Pathfinder mission will send a lander and a rover to the martian surface. Because of the extremely dry conditions on Mars, electrostatic charging of the rover is expected to occur as it moves about. Charge accumulation may result in high electrical potentials and discharge through the martian atmosphere. Such discharge could interfere with the operation of electrical elements on the rover. A strategy was sought to mitigate this charge accumulation as a precautionary measure. Ground tests were performed to demonstrate charging in laboratory conditions simulating the surface conditions expected at Mars. Tests showed that a rover wheel, driven at typical rover speeds, will accumulate electrical charge and develop significant electrical potentials (average observed, 110 volts). Measurements were made of wheel electrical potential, and wheel capacitance. From these quantities, the amount of absolute charge was estimated. An engineering solution was developed and recommended to mitigate charge accumulation. That solution has been implemented on the actual rover.

Development of RFI Mitigation Techniques with Digital Beamforming

NASA Technical Reports Server (NTRS)

Bollian, Tobias; Rincon, Rafael; Fatoyinbo, Temilola; Osmanoglu, Batuhan

2016-01-01

Remote sensing radars with longer wavelengths penetrate deeper into the observed scene and are more suitable for the scientific observation of ice sheets or vegetation. Therefore, SAR systems are moving to lower frequencies like L- or P-band. However, as the frequency spectrum is a limited resource, this means that the occupied frequency band has to be shared with existing users. These users can have serious impact on the imaging quality. Radio frequency interference (RFI) that arrives at the antenna together with the SAR backscatter is causing a drop of the signal-to-noise ratio. Despite the high processing gain of the SAR signal, artifacts can appear in the image if the RFI is strong enough. This can lead to a corruption of the acquired data and make it unsuitable for scientific purposes. Hence, the investigation of methods for RFI mitigation is critical to the performance of radar missions and to ensure they meet their main task.

No saturation in the accumulation of alien species worldwide.

PubMed

Seebens, Hanno; Blackburn, Tim M; Dyer, Ellie E; Genovesi, Piero; Hulme, Philip E; Jeschke, Jonathan M; Pagad, Shyama; Pyšek, Petr; Winter, Marten; Arianoutsou, Margarita; Bacher, Sven; Blasius, Bernd; Brundu, Giuseppe; Capinha, César; Celesti-Grapow, Laura; Dawson, Wayne; Dullinger, Stefan; Fuentes, Nicol; Jäger, Heinke; Kartesz, John; Kenis, Marc; Kreft, Holger; Kühn, Ingolf; Lenzner, Bernd; Liebhold, Andrew; Mosena, Alexander; Moser, Dietmar; Nishino, Misako; Pearman, David; Pergl, Jan; Rabitsch, Wolfgang; Rojas-Sandoval, Julissa; Roques, Alain; Rorke, Stephanie; Rossinelli, Silvia; Roy, Helen E; Scalera, Riccardo; Schindler, Stefan; Štajerová, Kateřina; Tokarska-Guzik, Barbara; van Kleunen, Mark; Walker, Kevin; Weigelt, Patrick; Yamanaka, Takehiko; Essl, Franz

2017-02-15

Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970-2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.

Assessing Inter-Sectoral Climate Change Risks: The Role of ISIMIP

NASA Technical Reports Server (NTRS)

Rosenzweig, Cynthia; Arnell, Nigel W.; Ebi, Kristie L.; Lotze-Campen, Hermann; Raes, Frank; Rapley, Chris; Smith, Mark Stafford; Cramer, Wolfgang; Frieler, Katja; Reyer, Christopher P. O.;

No saturation in the accumulation of alien species worldwide

PubMed Central

Seebens, Hanno; Blackburn, Tim M.; Dyer, Ellie E.; Genovesi, Piero; Hulme, Philip E.; Jeschke, Jonathan M.; Pagad, Shyama; Pyšek, Petr; Winter, Marten; Arianoutsou, Margarita; Bacher, Sven; Blasius, Bernd; Brundu, Giuseppe; Capinha, César; Celesti-Grapow, Laura; Dawson, Wayne; Dullinger, Stefan; Fuentes, Nicol; Jäger, Heinke; Kartesz, John; Kenis, Marc; Kreft, Holger; Kühn, Ingolf; Lenzner, Bernd; Liebhold, Andrew; Mosena, Alexander; Moser, Dietmar; Nishino, Misako; Pearman, David; Pergl, Jan; Rabitsch, Wolfgang; Rojas-Sandoval, Julissa; Roques, Alain; Rorke, Stephanie; Rossinelli, Silvia; Roy, Helen E.; Scalera, Riccardo; Schindler, Stefan; Štajerová, Kateřina; Tokarska-Guzik, Barbara; van Kleunen, Mark; Walker, Kevin; Weigelt, Patrick; Yamanaka, Takehiko; Essl, Franz

2017-01-01

Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization. PMID:28198420

Using Vegetation Barriers to Improving Wireless Network Isolation and Security

NASA Astrophysics Data System (ADS)

Cuiñas, Iñigo; Gómez, Paula; Sánchez, Manuel García; Alejos, Ana Vázquez

The increasing number of wireless LANs using the same spectrum allocation could induce multiple interferences and it also could force the active LANs to continuously retransmit data in order to solve this problem: this solution overloads the spectrum bands as well as collapses the LAN transmission capacity. This upcoming problem can be mitigated by using different techniques, being site shielding one of them. If radio systems could be safeguarded against radiation from transmitters out of the specific network, the frequency reuse is improved and, as a consequence, the number of WLANs sharing the same area may increase maintaining the required quality standards. The proposal of this paper is the use of bushes as a hurdle to attenuate signals from other networks and, so that, to defend the own wireless system from outer interferences. A measurement campaign has been performed in order to test this application of vegetal elements. This campaign was focused on determining the attenuation induced by several specimens of seven different vegetal species. Then, the relation between the induced attenuation and the interference from adjacent networks has been computed in terms of separation between networks. The network protection against outer unauthorized access could be also improved by means of the proposed technique.

Adaptive Detection and ISI Mitigation for Mobile Molecular Communication.

PubMed

Chang, Ge; Lin, Lin; Yan, Hao

2018-03-01

Current studies on modulation and detection schemes in molecular communication mainly focus on the scenarios with static transmitters and receivers. However, mobile molecular communication is needed in many envisioned applications, such as target tracking and drug delivery. Until now, investigations about mobile molecular communication have been limited. In this paper, a static transmitter and a mobile bacterium-based receiver performing random walk are considered. In this mobile scenario, the channel impulse response changes due to the dynamic change of the distance between the transmitter and the receiver. Detection schemes based on fixed distance fail in signal detection in such a scenario. Furthermore, the intersymbol interference (ISI) effect becomes more complex due to the dynamic character of the signal which makes the estimation and mitigation of the ISI even more difficult. In this paper, an adaptive ISI mitigation method and two adaptive detection schemes are proposed for this mobile scenario. In the proposed scheme, adaptive ISI mitigation, estimation of dynamic distance, and the corresponding impulse response reconstruction are performed in each symbol interval. Based on the dynamic channel impulse response in each interval, two adaptive detection schemes, concentration-based adaptive threshold detection and peak-time-based adaptive detection, are proposed for signal detection. Simulations demonstrate that the ISI effect is significantly reduced and the adaptive detection schemes are reliable and robust for mobile molecular communication.

The pyruvic acid analog 3-bromopyruvate interferes with the tetrazolium reagent MTS in the evaluation of cytotoxicity.

PubMed

Ganapathy-Kanniappan, Shanmugasundaram; Geschwind, Jean-Francois H; Kunjithapatham, Rani; Buijs, Manon; Syed, Labiq H; Rao, Pramod P; Ota, Shinichi; Vali, Mustafa

2010-04-01

3-Bromopyruvate (3BrPA) is a pyruvate analog known for its alkylating property. Recently, several reports have documented the antiglycolytic and anticancer effects of 3BrPA and its potential for therapeutic applications. 3BrPA-mediated cytotoxicity has been evaluated in vitro by various methods including tetrazolium salt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide)-based assays such as MTT, MTS, and so on. However, growing body of evidences has shown that tetrazolium reagent may interfere with the test compounds. In this study, we investigated whether the tetrazolium reagent interferes with the assessment of 3BrPA cytotoxicity. The results of the tetrazolium-based MTS assay were compared with 3 distinct cell viability detection methods, that is, Trypan Blue staining, ATP depletion, and Annexin V staining in 2 different cell lines, Vx-2 and HepG2. The MTS assay data showed false positive results by indicating increased cell viability at 1 mM and 2 mM 3BrPA whereas the other cell viability assays demonstrated that both Vx-2 and HepG2 cells are not viable at the same treatment conditions. In order to validate the direct interaction of 3BrPA with MTS reagent, we tested cell-free media incubated with different concentrations of 3BrPA. The results of cell-free media showed an increase in absorbance in a dose-dependent manner confirming the interaction of MTS with 3BrPA. Thus, our data clearly demonstrate that 3BrPA interferes with the accuracy of MTS-based cytotoxicity evaluation. Hence, we suggest that employing multiple methods of biochemical as well as morphological cytotoxicity assays is critical to evaluate 3BrPA-mediated cell death.

Cosine Directional Tuning of Theta Cell Burst Frequencies: Evidence for Spatial Coding by Oscillatory Interference

PubMed Central

Welday, Adam C.; Shlifer, I. Gary; Bloom, Matthew L.; Zhang, Kechen

2011-01-01

The rodent septohippocampal system contains “theta cells,” which burst rhythmically at 4–12 Hz, but the functional significance of this rhythm remains poorly understood (Buzsáki, 2006). Theta rhythm commonly modulates the spike trains of spatially tuned neurons such as place (O'Keefe and Dostrovsky, 1971), head direction (Tsanov et al., 2011a), grid (Hafting et al., 2005), and border cells (Savelli et al., 2008; Solstad et al., 2008). An “oscillatory interference” theory has hypothesized that some of these spatially tuned neurons may derive their positional firing from phase interference among theta oscillations with frequencies that are modulated by the speed and direction of translational movements (Burgess et al., 2005, 2007). This theory is supported by studies reporting modulation of theta frequency by movement speed (Rivas et al., 1996; Geisler et al., 2007; Jeewajee et al., 2008a), but modulation of theta frequency by movement direction has never been observed. Here we recorded theta cells from hippocampus, medial septum, and anterior thalamus of freely behaving rats. Theta cell burst frequencies varied as the cosine of the rat's movement direction, and this directional tuning was influenced by landmark cues, in agreement with predictions of the oscillatory interference theory. Computer simulations and mathematical analysis demonstrated how a postsynaptic neuron can detect location-dependent synchrony among inputs from such theta cells, and thereby mimic the spatial tuning properties of place, grid, or border cells. These results suggest that theta cells may serve a high-level computational function by encoding a basis set of oscillatory signals that interfere with one another to synthesize spatial memory representations. PMID:22072668

Antitumor Lipids--Structure, Functions, and Medical Applications.

PubMed

Kostadinova, Aneliya; Topouzova-Hristova, Tanya; Momchilova, Albena; Tzoneva, Rumiana; Berger, Martin R

2015-01-01

Cell proliferation and metastasis are considered hallmarks of tumor progression. Therefore, efforts have been made to develop novel anticancer drugs that inhibit both the proliferation and the motility of tumor cells. Synthetic antitumor lipids (ATLs), which are chemically divided into two main classes, comprise (i) alkylphospholipids (APLs) and (ii) alkylphosphocholines (APCs). They represent a new entity of drugs with distinct antiproliferative properties in tumor cells. These compounds do not interfere with the DNA or mitotic spindle apparatus of the cell, instead, they incorporate into cell membranes, where they accumulate and interfere with lipid metabolism and lipid-dependent signaling pathways. Recently, it has been shown that the most commonly studied APLs inhibit proliferation by inducing apoptosis in malignant cells while leaving normal cells unaffected and are potent sensitizers of conventional chemo- and radiotherapy, as well as of electrical field therapy. APLs resist catabolic degradation to a large extent, therefore accumulate in the cell and interfere with lipid-dependent survival signaling pathways, notably PI3K-Akt and Raf-Erk1/2, and de novo phospholipid biosynthesis. They are internalized in the cell membrane via raft domains and cause downstream reactions as inhibition of cell growth and migration, cell cycle arrest, actin stress fibers collapse, and apoptosis. This review summarizes the in vitro, in vivo, and clinical trials of most common ATLs and their mode of action at molecular and biochemical levels. © 2015 Elsevier Inc. All rights reserved.

White Sturgeon Mitigation and Restoration in the Columbia and Snake Rivers Upstream from Bonneville Dam; Annual Progress Report, April 2007 - March 2008.

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

Mallette, Christine

2009-07-28

We report on our progress from April 2007 through March 2008 on determining the effects of mitigative measures on productivity of white sturgeon populations in the Columbia River downstream from McNary Dam, and on determining the status and habitat requirements of white sturgeon populations in the Columbia and Snake rivers upstream from McNary Dam. The study is a cooperative effort by the Oregon Department of Fish and Wildlife (ODFW; Report A), Washington Department of Fish and Wildlife (WDFW; Report B), Columbia River Inter-Tribal Fish Commission (CRITFC; Report C), and Montana State University (MSU; Report D). This is a multi-year studymore » with many objectives requiring more than one year to complete; therefore, findings from a given year may be part of more significant findings yet to be reported.« less

Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System

NASA Astrophysics Data System (ADS)

Bhende, C. N.; Kalam, A.; Malla, S. G.

2016-04-01

Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.

Line edge roughness (LER) mitigation studies specific to interference-like lithography

NASA Astrophysics Data System (ADS)

Baylav, Burak; Estroff, Andrew; Xie, Peng; Smith, Bruce W.

2013-04-01

Line edge roughness (LER) is a common problem to most lithography approaches and is seen as the main resolution limiter for advanced technology nodes1. There are several contributors to LER such as chemical/optical shot noise, random nature of acid diffusion, development process, and concentration of acid generator/base quencher. Since interference-like lithography (IL) is used to define one directional gridded patterns, some LER mitigation approaches specific to IL-like imaging can be explored. Two methods investigated in this work for this goal are (i) translational image averaging along the line direction and (ii) pupil plane filtering. Experiments regarding the former were performed on both interferometric and projection lithography systems. Projection lithography experiments showed a small amount of reduction in low/mid frequency LER value for image averaged cases at pitch of 150 nm (193 nm illumination, 0.93 NA) with less change for smaller pitches. Aerial image smearing did not significantly increase LER since it was directional. Simulation showed less than 1% reduction in NILS (compared to a static, smooth mask equivalent) with ideal alignment. In addition, description of pupil plane filtering on the transfer of mask roughness is given. When astigmatism-like aberrations were introduced in the pupil, transfer of mask roughness is decreased at best focus. It is important to exclude main diffraction orders from the filtering to prevent contrast and NILS loss. These ideas can be valuable as projection lithography approaches to conditions similar to IL (e.g. strong RET methods).

Cell Membrane Tracking in Living Brain Tissue Using Differential Interference Contrast Microscopy.

PubMed

Lee, John; Kolb, Ilya; Forest, Craig R; Rozell, Christopher J

2018-04-01

Differential interference contrast (DIC) microscopy is widely used for observing unstained biological samples that are otherwise optically transparent. Combining this optical technique with machine vision could enable the automation of many life science experiments; however, identifying relevant features under DIC is challenging. In particular, precise tracking of cell boundaries in a thick ( ) slice of tissue has not previously been accomplished. We present a novel deconvolution algorithm that achieves the state-of-the-art performance at identifying and tracking these membrane locations. Our proposed algorithm is formulated as a regularized least squares optimization that incorporates a filtering mechanism to handle organic tissue interference and a robust edge-sparsity regularizer that integrates dynamic edge tracking capabilities. As a secondary contribution, this paper also describes new community infrastructure in the form of a MATLAB toolbox for accurately simulating DIC microscopy images of in vitro brain slices. Building on existing DIC optics modeling, our simulation framework additionally contributes an accurate representation of interference from organic tissue, neuronal cell-shapes, and tissue motion due to the action of the pipette. This simulator allows us to better understand the image statistics (to improve algorithms), as well as quantitatively test cell segmentation and tracking algorithms in scenarios, where ground truth data is fully known.

Quantifying the increasing sensitivity of power systems to climate variability

NASA Astrophysics Data System (ADS)

Bloomfield, H. C.; Brayshaw, D. J.; Shaffrey, L. C.; Coker, P. J.; Thornton, H. E.

2016-12-01

Large quantities of weather-dependent renewable energy generation are expected in power systems under climate change mitigation policies, yet little attention has been given to the impact of long term climate variability. By combining state-of-the-art multi-decadal meteorological records with a parsimonious representation of a power system, this study characterises the impact of year-to-year climate variability on multiple aspects of the power system of Great Britain (including coal, gas and nuclear generation), demonstrating why multi-decadal approaches are necessary. All aspects of the example system are impacted by inter-annual climate variability, with the impacts being most pronounced for baseload generation. The impacts of inter-annual climate variability increase in a 2025 wind-power scenario, with a 4-fold increase in the inter-annual range of operating hours for baseload such as nuclear. The impacts on peak load and peaking-plant are comparably small. Less than 10 years of power supply and demand data are shown to be insufficient for providing robust power system planning guidance. This suggests renewable integration studies—widely used in policy, investment and system design—should adopt a more robust approach to climate characterisation.

A most spectrum-efficient duplexing system: CDD

NASA Astrophysics Data System (ADS)

Lee, William C. Y.

2001-10-01

The game to play in wireless communications when it comes to increasing spectrum efficiency is to eliminate interference. Currently, all cellular systems use FDD (Frequency Division Duplexing) in an attempt to eliminate the interference from the adjacent cells. Through the use of many technologies only one type of interference remains and that is the adjacent base-tohome mobile interference. TDD (Time Division Duplexing) has not been used for mobile cellular systems, not only because of the adjacent base-to-home mobile interference, but also because of the additional adjacent base-to-home base interference, and adjacent mobile-to-home mobile interference. Therefore, TDD can only be used for small, confined area systems. CDD (Code Division Duplexing) can eliminate all three kinds of interference; the adjacent base-to-home mobile, the adjacent baseto-home base, and the adjacent mobile- to- home in cellular systems. Eliminating each of these interferences makes CDD the most spectrum efficient duplexing system. This talk will elaborate on a set of smart codes, which will make an efficient CDD system a reality.

Preface: cardiac control pathways: signaling and transport phenomena.

PubMed

Sideman, Samuel

2008-03-01

Signaling is part of a complex system of communication that governs basic cellular functions and coordinates cellular activity. Transfer of ions and signaling molecules and their interactions with appropriate receptors, transmembrane transport, and the consequent intracellular interactions and functional cellular response represent a complex system of interwoven phenomena of transport, signaling, conformational changes, chemical activation, and/or genetic expression. The well-being of the cell thus depends on a harmonic orchestration of all these events and the existence of control mechanisms that assure the normal behavior of the various parameters involved and their orderly expression. The ability of cells to sustain life by perceiving and responding correctly to their microenvironment is the basis for development, tissue repair, and immunity, as well as normal tissue homeostasis. Natural deviations, or human-induced interference in the signaling pathways and/or inter- and intracellular transport and information transfer, are responsible for the generation, modulation, and control of diseases. The present overview aims to highlight some major topics of the highly complex cellular information transfer processes and their control mechanisms. Our goal is to contribute to the understanding of the normal and pathophysiological phenomena associated with cardiac functions so that more efficient therapeutic modalities can be developed. Our objective in this volume is to identify and enhance the study of some basic passive and active physical and chemical transport phenomena, physiological signaling pathways, and their biological consequences.

New spatial diversity equalizer based on PLL

NASA Astrophysics Data System (ADS)

Rao, Wei

2011-10-01

A new Spatial Diversity Equalizer (SDE) based on phase-locked loop (PLL) is proposed to overcome the inter-symbol interference (ISI) and phase rotations simultaneously in the digital communication system. The proposed SDE consists of equal gain combining technique based on a famous blind equalization algorithm constant modulus algorithm (CMA) and a PLL. Compared with conventional SDE, the proposed SDE has not only faster convergence rate and lower residual error but also the ability to recover carrier phase rotation. The efficiency of the method is proved by computer simulation.

Optimal designs of bioretention cells in shallow groundwater

NASA Astrophysics Data System (ADS)

Zhang, K.; Chui, T. F. M.

2017-12-01

Bioretention cells, as one representative low impact development practices, have been proved to be effective in controlling surface runoff, removing pollutants and recharging groundwater. However, they are often not recommended in shallow groundwater areas due to potential groundwater pollution, reduction in runoff control performance and groundwater drainage through the underdrain. Most design guidelines only require a minimum distance between bioretention cell bottom and seasonal high groundwater table without guiding the design of bioretention cells to mitigate the problem of shallow groundwater. This study therefore proposed some design recommendations of bioretention cells for different rainfall runoff loads, native soil types and initial water table depths. A variably saturated flow model was employed to conduct event-based simulations on one single hypothetical bioretention cell in shallow groundwater, which was calibrated using experimental and simulation data of an on-site bioretention cell. A wide range of climatic and geophysical factors (i.e. initial groundwater depths, native soils, rainfall runoff loads) and bioretention designs (i.e. media soil types and underdrain sizes) were considered. Surface runoff reduction, time before groundwater mound formation, as well as maximum height of groundwater mound were evaluated. Less-permeable media types (i.e. sandy loam) are recommended in areas with many extreme rainfall events (i.e. 40 - 70 mm/h or larger) and of shallower groundwater, which can better protect groundwater from mounding and possibly contamination although may slightly compromise the runoff control performance. For areas having seasonal high groundwater table of 0 - 1 m below bioretention bottom, underdrain is recommended to maintain good infiltration capacity without draining groundwater. However, underdrain is not recommended for areas of groundwater table always near or above the bioretention bottom, only if an impermeable sheet is added. Generally, groundwater interference is a concern only when groundwater table is above 1 - 2.5 m below bioretention bottom and runoff loads are very high. The results of this study overall could benefit the implementation of bioretention cells in shallow groundwater areas, and the establishment of relevant design guidelines.

Visualizing multiple inter-organelle contact sites using the organelle-targeted split-GFP system.

PubMed

Kakimoto, Yuriko; Tashiro, Shinya; Kojima, Rieko; Morozumi, Yuki; Endo, Toshiya; Tamura, Yasushi

2018-04-18

Functional integrity of eukaryotic organelles relies on direct physical contacts between distinct organelles. However, the entity of organelle-tethering factors is not well understood due to lack of means to analyze inter-organelle interactions in living cells. Here we evaluate the split-GFP system for visualizing organelle contact sites in vivo and show its advantages and disadvantages. We observed punctate GFP signals from the split-GFP fragments targeted to any pairs of organelles among the ER, mitochondria, peroxisomes, vacuole and lipid droplets in yeast cells, which suggests that these organelles form contact sites with multiple organelles simultaneously although it is difficult to rule out the possibilities that these organelle contacts sites are artificially formed by the irreversible associations of the split-GFP probes. Importantly, split-GFP signals in the overlapped regions of the ER and mitochondria were mainly co-localized with ERMES, an authentic ER-mitochondria tethering structure, suggesting that split-GFP assembly depends on the preexisting inter-organelle contact sites. We also confirmed that the split-GFP system can be applied to detection of the ER-mitochondria contact sites in HeLa cells. We thus propose that the split-GFP system is a potential tool to observe and analyze inter-organelle contact sites in living yeast and mammalian cells.

Phase resolved and coherence gated en face reflection imaging of multilayered embryonal carcinoma cells

NASA Astrophysics Data System (ADS)

Yamauchi, Toyohiko; Fukami, Tadashi; Iwai, Hidenao; Yamashita, Yutaka

2012-03-01

Embryonal carcinoma (EC) cells, which are cell lines derived from teratocarcinomas, have characteristics in common with stem cells and differentiate into many kinds of functional cells. Similar to embryonic stem (ES) cells, undifferentiated EC cells form multi-layered spheroids. In order to visualize the three-dimensional structure of multilayered EC cells without labeling, we employed full-field interference microscopy with the aid of a low-coherence quantitative phase microscope, which is a reflection-type interference microscope employing the digital holographic technique with a low-coherent light source. Owing to the low-coherency of the light-source (halogen lamp), only the light reflected from reflective surface at a specific sectioning height generates an interference image on the CCD camera. P19CL6 EC cells, derived from mouse teratocarcinomas, formed spheroids that are about 50 to 200 micrometers in diameter. Since the height of each cell is around 10 micrometers, it is assumed that each spheroid has 5 to 20 cell layers. The P19CL6 spheroids were imaged in an upright configuration and the horizontally sectioned reflection images of the sample were obtained by sequentially and vertically scanning the zero-path-length height. Our results show the threedimensional structure of the spheroids, in which plasma and nuclear membranes were distinguishably imaged. The results imply that our technique is further capable of imaging induced pluripotent stem (iPS) cells for the assessment of cell properties including their pluripotency.

Aberrant expression of the tight junction molecules claudin-1 and zonula occludens-1 mediates cell growth and invasion in oral squamous cell carcinoma.

PubMed

Babkair, Hamzah; Yamazaki, Manabu; Uddin, Md Shihab; Maruyama, Satoshi; Abé, Tatsuya; Essa, Ahmed; Sumita, Yoshimasa; Ahsan, Md Shahidul; Swelam, Wael; Cheng, Jun; Saku, Takashi

2016-11-01

We reported that altered cell contact mediated by E-cadherin is an initial event in the pathogenesis of oral epithelial malignancies. To assess other effects of cell adhesion, we examined the expression levels of tight junction (TJ) molecules in oral carcinoma in situ (CIS) and squamous cell carcinoma (SCC). To identify changes in the expression of TJ molecules, we conducted an analysis of the immunohistochemical profiles of claudin-1 (CLDN-1) and zonula occludens-1 (ZO-1) in surgical specimens acquired from patients with oral SCC containing foci of epithelial dysplasia or from patients with CIS. We used immunofluorescence, Western blotting, reverse-transcription polymerase chain reaction, and RNA interference to evaluate the functions of CLDN-1 and ZO-1 in cultured oral SCC cells. TJ molecules were not detected in normal oral epithelial tissues but were expressed in SCC/CIS cells. ZO-1 was localized within the nucleus of proliferating cells. When CLDN-1 expression was inhibited by transfecting cells with specific small interference RNAs, SCC cells dissociated, and their ability to proliferate and invade Matrigel was inhibited. In contrast, although RNA interference-mediated inhibition of ZO-1 expression did not affect cell morphology, it inhibited cell proliferation and invasiveness. Our findings indicated that the detection of TJ molecules in the oral epithelia may serve as a marker for the malignant phenotype of cells in which CLDN-1 regulates proliferation and invasion. Copyright © 2016 Elsevier Inc. All rights reserved.

Enhanced susceptibility of cancer cells to oncolytic rhabdo-virotherapy by expression of Nodamura virus protein B2 as a suppressor of RNA interference.

PubMed

Bastin, Donald; Aitken, Amelia S; Pelin, Adrian; Pikor, Larissa A; Crupi, Mathieu J F; Huh, Michael S; Bourgeois-Daigneault, Marie-Claude; Bell, John C; Ilkow, Carolina S

2018-06-19

Antiviral responses are barriers that must be overcome for efficacy of oncolytic virotherapy. In mammalian cells, antiviral responses involve the interferon pathway, a protein-signaling cascade that alerts the immune system and limits virus propagation. Tumour-specific defects in interferon signaling enhance viral infection and responses to oncolytic virotherapy, but many human cancers are still refractory to oncolytic viruses. Given that invertebrates, fungi and plants rely on RNA interference pathways for antiviral protection, we investigated the potential involvement of this alternative antiviral mechanism in cancer cells. Here, we detected viral genome-derived small RNAs, indicative of RNAi-mediated antiviral responses, in human cancer cells. As viruses may encode suppressors of the RNA interference pathways, we engineered an oncolytic vesicular stomatitis virus variant to encode the Nodamura virus protein B2, a known inhibitor of RNAi-mediated immune responses. B2-expressing oncolytic virus showed enhanced viral replication and cytotoxicity, impaired viral genome cleavage and altered microRNA processing in cancer cells. Our data establish the improved therapeutic potential of our novel virus which targets the RNAi-mediated antiviral defense of cancer cells.

Mitigating Thermal Runaway Risk in Lithium Ion Batteries

NASA Technical Reports Server (NTRS)

Darcy, Eric; Jeevarajan, Judy; Russell, Samuel

2014-01-01

The JSC/NESC team has successfully demonstrated Thermal Runaway (TR) risk reduction in a lithium ion battery for human space flight by developing and implementing verifiable design features which interrupt energy transfer between adjacent electrochemical cells. Conventional lithium ion (li-Ion) batteries can fail catastrophically as a result of a single cell going into thermal runaway. Thermal runaway results when an internal component fails to separate electrode materials leading to localized heating and complete combustion of the lithium ion cell. Previously, the greatest control to minimize the probability of cell failure was individual cell screening. Combining thermal runaway propagation mitigation design features with a comprehensive screening program reduces both the probability, and the severity, of a single cell failure.

Glyceryl trinitrate and caprylic acid for the mitigation of the Desulfovibrio vulgaris biofilm on C1018 carbon steel.

PubMed

Li, Y; Zhang, P; Cai, W; Rosenblatt, J S; Raad, I I; Xu, D; Gu, T

2016-02-01

Microbiologically influenced corrosion (MIC), also known as biocorrosion, is caused by corrosive biofilms. MIC is a growing problem, especially in the oil and gas industry. Among various corrosive microbes, sulfate reducing bacteria (SRB) are often the leading culprit. Biofilm mitigation is the key to MIC mitigation. Biocide applications against biofilms promote resistance over time. Thus, it is imperative to develop new biodegradable and cost-effective biocides for large-scale field applications. Using the corrosive Desulfovibrio vulgaris (an SRB) biofilm as a model biofilm, this work demonstrated that a cocktail of glyceryl trinitrate (GTN) and caprylic acid (CA) was very effective for biofilm prevention and mitigation of established biofilms on C1018 carbon steel coupons. The most probable number sessile cell count data and confocal laser scanning microscope biofilm images proved that the biocide cocktail of 25 ppm (w/w) GTN + 0.1% (w/w) CA successfully prevented the D. vulgaris biofilm establishment on C1018 carbon steel coupons while 100 ppm GTN + 0.1% CA effectively mitigated pre-established D. vulgaris biofilms on C1018 carbon steel coupons. In both cases, the cocktails were able to reduce the sessile cell count from 10(6) cells/cm(2) to an undetectable level.

Infection of Mosquito Cells (C6/36) by Dengue-2 Virus Interferes with Subsequent Infection by Yellow Fever Virus.

PubMed

Abrao, Emiliana Pereira; da Fonseca, Benedito Antônio Lopes

2016-02-01

Dengue is one of the most important diseases caused by arboviruses in the world. Yellow fever is another arthropod-borne disease of great importance to public health that is endemic to tropical regions of Africa and the Americas. Both yellow fever and dengue viruses are flaviviruses transmitted by Aedes aegypti mosquitoes, and then, it is reasonable to consider that in a given moment, mosquito cells could be coinfected by both viruses. Therefore, we decided to evaluate if sequential infections of dengue and yellow fever viruses (and vice-versa) in mosquito cells could affect the virus replication patterns. Using immunofluorescence and real-time PCR-based replication assays in Aedes albopictus C6/36 cells with single or sequential infections with both viruses, we demonstrated the occurrence of viral interference, also called superinfection exclusion, between these two viruses. Our results show that this interference pattern is particularly evident when cells were first infected with dengue virus and subsequently with yellow fever virus (YFV). Reduction in dengue virus replication, although to a lower extent, was also observed when C6/36 cells were initially infected with YFV followed by dengue virus infection. Although the importance that these findings have on nature is unknown, this study provides evidence, at the cellular level, of the occurrence of replication interference between dengue and yellow fever viruses and raises the question if superinfection exclusion could be a possible explanation, at least partially, for the reported lack of urban yellow fever occurrence in regions where a high level of dengue transmission occurs.

Performance Analysis of Integrated Wireless Sensor and Multibeam Satellite Networks Under Terrestrial Interference

PubMed Central

Li, Hongjun; Yin, Hao; Gong, Xiangwu; Dong, Feihong; Ren, Baoquan; He, Yuanzhi; Wang, Jingchao

2016-01-01

This paper investigates the performance of integrated wireless sensor and multibeam satellite networks (IWSMSNs) under terrestrial interference. The IWSMSNs constitute sensor nodes (SNs), satellite sinks (SSs), multibeam satellite and remote monitoring hosts (RMHs). The multibeam satellite covers multiple beams and multiple SSs in each beam. The SSs can be directly used as SNs to transmit sensing data to RMHs via the satellite, and they can also be used to collect the sensing data from other SNs to transmit to the RMHs. We propose the hybrid one-dimensional (1D) and 2D beam models including the equivalent intra-beam interference factor β from terrestrial communication networks (TCNs) and the equivalent inter-beam interference factor α from adjacent beams. The terrestrial interference is possibly due to the signals from the TCNs or the signals of sinks being transmitted to other satellite networks. The closed-form approximations of capacity per beam are derived for the return link of IWSMSNs under terrestrial interference by using the Haar approximations where the IWSMSNs experience the Rician fading channel. The optimal joint decoding capacity can be considered as the upper bound where all of the SSs’ signals can be jointly decoded by a super-receiver on board the multibeam satellite or a gateway station that knows all of the code books. While the linear minimum mean square error (MMSE) capacity is where all of the signals of SSs are decoded singularly by a multibeam satellite or a gateway station. The simulations show that the optimal capacities are obviously higher than the MMSE capacities under the same conditions, while the capacities are lowered by Rician fading and converge as the Rician factor increases. α and β jointly affect the performance of hybrid 1D and 2D beam models, and the number of SSs also contributes different effects on the optimal capacity and MMSE capacity of the IWSMSNs. PMID:27754438

Transportable and vibration-free full-field low-coherent quantitative phase microscope

NASA Astrophysics Data System (ADS)

Yamauchi, Toyohiko; Yamada, Hidenao; Goto, Kentaro; Matsui, Hisayuki; Yasuhiko, Osamu; Ueda, Yukio

2018-02-01

We developed a transportable Linnik-type full-field low-coherent quantitative phase microscope that is able to compensate for optical path length (OPL) disturbance due to environmental mechanical noises. Though two-beam interferometers such as Linnik ones suffer from unstable OPL difference, we overcame this problem with a mechanical feedback system based on digital signal-processing that controls the OPL difference in sub-nanometer resolution precisely with a feedback bandwidth of 4 kHz. The developed setup has a footprint of 200 mm by 200 mm, a height of 500 mm, and a weight of 4.5 kilograms. In the transmission imaging mode, cells were cultured on a reflection-enhanced glass-bottom dish, and we obtained interference images sequentially while performing stepwise quarter-wavelength phase-shifting. Real-time image processing, including retrieval of the unwrapped phase from interference images and its background correction, along with the acquisition of interference images, was performed on a laptop computer. Emulation of the phase contrast (PhC) images and the differential interference contrast (DIC) images was also performed in real time. Moreover, our setup was applied for full-field cell membrane imaging in the reflection mode, where the cells were cultured on an anti-reflection (AR)-coated glass-bottom dish. The phase and intensity of the light reflected by the membrane revealed the outer shape of the cells independent of the refractive index. In this paper, we show imaging results on cultured cells in both transmission and reflection modes.

The Use of ICP-MS and IC-ICP-MS in Environmental and Exposure Assesssment

EPA Science Inventory

OVERVIEW: Application of collision/reaction cell interference reduction technology for the minimization of polyatomic interferences in environmental matrices. Improved risk assessments through the use of arsenic speciation approaches that estimate the bio-accessibility asso...

Balancing Uplink and Downlink under Asymmetric Traffic Environments Using Distributed Receive Antennas

NASA Astrophysics Data System (ADS)

Sohn, Illsoo; Lee, Byong Ok; Lee, Kwang Bok

Recently, multimedia services are increasing with the widespread use of various wireless applications such as web browsers, real-time video, and interactive games, which results in traffic asymmetry between the uplink and downlink. Hence, time division duplex (TDD) systems which provide advantages in efficient bandwidth utilization under asymmetric traffic environments have become one of the most important issues in future mobile cellular systems. It is known that two types of intercell interference, referred to as crossed-slot interference, additionally arise in TDD systems; the performances of the uplink and downlink transmissions are degraded by BS-to-BS crossed-slot interference and MS-to-MS crossed-slot interference, respectively. The resulting performance unbalance between the uplink and downlink makes network deployment severely inefficient. Previous works have proposed intelligent time slot allocation algorithms to mitigate the crossed-slot interference problem. However, they require centralized control, which causes large signaling overhead in the network. In this paper, we propose to change the shape of the cellular structure itself. The conventional cellular structure is easily transformed into the proposed cellular structure with distributed receive antennas (DRAs). We set up statistical Markov chain traffic model and analyze the bit error performances of the conventional cellular structure and proposed cellular structure under asymmetric traffic environments. Numerical results show that the uplink and downlink performances of the proposed cellular structure become balanced with the proper number of DRAs and thus the proposed cellular structure is notably cost-effective in network deployment compared to the conventional cellular structure. As a result, extending the conventional cellular structure into the proposed cellular structure with DRAs is a remarkably cost-effective solution to support asymmetric traffic environments in future mobile cellular systems.

Genome-Wide Association Study of L-Arginine and Dimethylarginines Reveals Novel Metabolic Pathway for Symmetric Dimethylarginine

PubMed Central

Lüneburg, Nicole; Lieb, Wolfgang; Zeller, Tanja; Chen, Ming-Huei; Maas, Renke; Carter, Angela M.; Xanthakis, Vanessa; Glazer, Nicole L; Schwedhelm, Edzard; Seshadri, Sudha; Ikram, M. Arfan; Longstreth, W.T.; Fornage, Myriam; König, Inke R.; Loley, Christina; Ojeda, Francisco M.; Schillert, Arne; Wang, Thomas J.; Sticht, Heinrich; Kittel, Anja; König, Jörg; Benjamin, Emelia J.; Sullivan, Lisa M.; Bernges, Isabel; Anderssohn, Maike; Ziegler, Andreas; Gieger, Christian; Illig, Thomas; Meisinger, Christa; Wichmann, H.-Erich; Wild, Philipp S.; Schunkert, Heribert; Psaty, Bruce M.; Wiggins, Kerri L.; Heckbert, Susan R.; Smith, Nicholas; Lackner, Karl; Lunetta, Kathryn L.; Blankenberg, Stefan; Erdmann, Jeanette; Munzel, Thomas; Grant, Peter J.; Vasan, Ramachandran S.; Böger, Rainer H.

2016-01-01

Background Dimethylarginines (DMA) interfere with nitric oxide (NO) formation by inhibiting NO synthase (asymmetric dimethylarginine, ADMA) and L-arginine uptake into the cell (ADMA and symmetric dimethylarginine, SDMA). In prospective clinical studies ADMA has been characterized as a cardiovascular risk marker whereas SDMA is a novel marker for renal function and associated with all-cause mortality after ischemic stroke. The aim of the current study was to characterise the environmental and genetic contributions to inter-individual variability of these biomarkers. Methods and Results This study comprised a genome-wide association analysis of 3 well-characterized population-based cohorts (FHS (n=2992), GHS (n=4354) and MONICA/KORA F3 (n=581)) and identified replicated loci (DDAH1, MED23, Arg1 and AGXT2) associated with the inter-individual variability in ADMA, L-arginine and SDMA. Experimental in-silico and in-vitro studies confirmed functional significance of the identified AGXT2 variants. Clinical outcome analysis in 384 patients of the Leeds stroke study demonstrated an association between increased plasma levels of SDMA, AGXT2 variants and various cardiometabolic risk factors. AGXT2 variants were not associated with post-stroke survival in the Leeds study, nor were they associated with incident stroke in the CHARGE consortium. Conclusion These GWAS support the importance of DDAH1 and MED23/Arg1 in regulating ADMA and L-arginine metabolism, respectively, and identify a novel regulatory renal pathway for SDMA by AGXT2. AGXT2 variants might explain part of the pathogenic link between SDMA, renal function, and outcome. An association between AGXT2 variants and stroke is unclear and warrants further investigation. PMID:25245031

Intercellular communications-redox interactions in radiation toxicity; potential targets for radiation mitigation.

PubMed

Farhood, Bagher; Goradel, Nasser Hashemi; Mortezaee, Keywan; Khanlarkhani, Neda; Salehi, Ensieh; Nashtaei, Maryam Shabani; Shabeeb, Dheyauldeen; Musa, Ahmed Eleojo; Fallah, Hengameh; Najafi, Masoud

2018-06-17

Nowadays, using ionizing radiation (IR) is necessary for clinical, agricultural, nuclear energy or industrial applications. Accidental exposure to IR after a radiation terror or disaster poses a threat to human. In contrast to the old dogma of radiation toxicity, several experiments during the last two recent decades have revealed that intercellular signaling and communications play a key role in this procedure. Elevated level of cytokines and other intercellular signals increase oxidative damage and inflammatory responses via reduction/oxidation interactions (redox system). Intercellular signals induce production of free radicals and inflammatory mediators by some intermediate enzymes such as cyclooxygenase-2 (COX-2), nitric oxide synthase (NOS), NADPH oxidase, and also via triggering mitochondrial ROS. Furthermore, these signals facilitate cell to cell contact and increasing cell toxicity via cohort effect. Nitric oxide is a free radical with ability to act as an intercellular signal that induce DNA damage and changes in some signaling pathways in irradiated as well as non-irradiated adjacent cells. Targeting of these mediators by some anti-inflammatory agents or via antioxidants such as mitochondrial ROS scavengers opens a window to mitigate radiation toxicity after an accidental exposure. Experiments which have been done so far suggests that some cytokines such as IL-1β, TNF-α, TGF-β, IL-4 and IL-13 are some interesting targets that depend on irradiated organs and may help mitigate radiation toxicity. Moreover, animal experiments in recent years indicated that targeting of toll like receptors (TLRs) may be more useful for radioprotection and mitigation. In this review, we aimed to describe the role of intercellular interactions in oxidative injury, inflammation, cell death and killing effects of IR. Moreover, we described evidence on potential mitigation of radiation injury via targeting of these mediators.

Deterministic filtering of breakdown flashing at telecom wavelengths

NASA Astrophysics Data System (ADS)

Marini, Loris; Camphausen, Robin; Eggleton, Benjamin J.; Palomba, Stefano

2017-11-01

Breakdown flashes are undesired photo-emissions from the active area of single-photon avalanche photo-diodes. They arise from radiative recombinations of hot carriers generated during an avalanche and can induce crosstalk, compromise the measurement of optical quantum states, and hinder the security of quantum communications. Although the spectrum of this emission extends over hundreds of nanometers, active quenching may lead to a smaller uncertainty in the time of emission, thus enabling deterministic filtering. Our results pave the way to broadband interference mitigation in time-correlated single-photon applications.

Bioelectrocatalytic NAD+/NADH inter-conversion: transformation of an enzymatic fuel cell into an enzymatic redox flow battery.

PubMed

Quah, Timothy; Milton, Ross D; Abdellaoui, Sofiene; Minteer, Shelley D

2017-07-25

Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD + . We demonstrate how bioelectrocatalytic NAD + /NADH inter-conversion can transform a glucose/O 2 enzymatic fuel cell (EFC) with an open circuit potential (OCP) of 1.1 V into an enzymatic redox flow battery (ERFB), which can be rapidly recharged by operation as an EFC.

SDN-controlled topology-reconfigurable optical mobile fronthaul architecture for bidirectional CoMP and low latency inter-cell D2D in the 5G mobile era.

PubMed

Cvijetic, Neda; Tanaka, Akihiro; Kanonakis, Konstantinos; Wang, Ting

2014-08-25

We demonstrate the first SDN-controlled optical topology-reconfigurable mobile fronthaul (MFH) architecture for bidirectional coordinated multipoint (CoMP) and low latency inter-cell device-to-device (D2D) connectivity in the 5G mobile networking era. SDN-based OpenFlow control is used to dynamically instantiate the CoMP and inter-cell D2D features as match/action combinations in control plane flow tables of software-defined optical and electrical switching elements. Dynamic re-configurability is thereby introduced into the optical MFH topology, while maintaining back-compatibility with legacy fiber deployments. 10 Gb/s peak rates with <7 μs back-to-back transmission latency and 29.6 dB total power budget are experimentally demonstrated, confirming the attractiveness of the new approach for optical MFH of future 5G mobile systems.

Overcoming interference with the detection of a stable isotopically labeled microtracer in the evaluation of beclabuvir absolute bioavailability using a concomitant microtracer approach.

PubMed

Jiang, Hao; Titsch, Craig; Zeng, Jianing; Jones, Barry; Joyce, Philip; Gandhi, Yash; Turley, Wesley; Burrell, Richard; Aubry, Anne F; Arnold, Mark E

2017-09-05

The oral absolute bioavailability of beclabuvir in healthy subjects was determined using a microdose (100μg) of the stable isotopically labeled tracer via intravenous (IV) infusion started after oral dosing of beclabuvir (150mg). To simultaneously analyze the concentrations of the IV microtracer ([ 13 C 6 ]beclabuvir) and beclabuvir in plasma samples, a liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) method was initially developed. Surprisingly beclabuvir significantly interfered with the IV microtracer detection when using the selected reaction monitoring (SRM) in the assay. An interfering component from the drug substance was observed using a high resolution mass spectrometer (HRMS). The mass-to-charge (m/z) of the interfering component was -32ppm different from the nominal value for the IV microtracer and thus could not be differentiated in the SRM assay by the unit mass resolution. To overcome this interference, we evaluated two approaches by either monitoring an alternative product ion using the SRM assay or isolating the interfering component using the parallel reaction monitoring (PRM) assay on the HRMS. This case study has demonstrated two practical approaches for overcoming interferences with the detection of stable isotopically labeled IV microtracers in the evaluation of absolute bioavailability, which provides users the flexibility in using either LC-MS/MS or HRMS to mitigate unpredicted interferences in the assay to support microtracer absolute bioavailability studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Neuromodulation on Excitatory-Inhibitory Neural Network Dynamics Depend on Network Connectivity Structure

NASA Astrophysics Data System (ADS)

Rich, Scott; Zochowski, Michal; Booth, Victoria

2018-01-01

Acetylcholine (ACh), one of the brain's most potent neuromodulators, can affect intrinsic neuron properties through blockade of an M-type potassium current. The effect of ACh on excitatory and inhibitory cells with this potassium channel modulates their membrane excitability, which in turn affects their tendency to synchronize in networks. Here, we study the resulting changes in dynamics in networks with inter-connected excitatory and inhibitory populations (E-I networks), which are ubiquitous in the brain. Utilizing biophysical models of E-I networks, we analyze how the network connectivity structure in terms of synaptic connectivity alters the influence of ACh on the generation of synchronous excitatory bursting. We investigate networks containing all combinations of excitatory and inhibitory cells with high (Type I properties) or low (Type II properties) modulatory tone. To vary network connectivity structure, we focus on the effects of the strengths of inter-connections between excitatory and inhibitory cells (E-I synapses and I-E synapses), and the strengths of intra-connections among excitatory cells (E-E synapses) and among inhibitory cells (I-I synapses). We show that the presence of ACh may or may not affect the generation of network synchrony depending on the network connectivity. Specifically, strong network inter-connectivity induces synchronous excitatory bursting regardless of the cellular propensity for synchronization, which aligns with predictions of the PING model. However, when a network's intra-connectivity dominates its inter-connectivity, the propensity for synchrony of either inhibitory or excitatory cells can determine the generation of network-wide bursting.

Disruption of lipid rafts interferes with the interaction of Toxoplasma gondii with macrophages and epithelial cells.

PubMed

Cruz, Karla Dias; Cruz, Thayana Araújo; Veras de Moraes, Gabriela; Paredes-Santos, Tatiana Christina; Attias, Marcia; de Souza, Wanderley

2014-01-01

The intracellular parasite Toxoplasma gondii can penetrate any warm-blooded animal cell. Conserved molecular assemblies of host cell plasma membranes should be involved in the parasite-host cell recognition. Lipid rafts are well-conserved membrane microdomains that contain high concentrations of cholesterol, sphingolipids, glycosylphosphatidylinositol, GPI-anchored proteins, and dually acylated proteins such as members of the Src family of tyrosine kinases. Disturbing lipid rafts of mouse peritoneal macrophages and epithelial cells of the lineage LLC-MK2 with methyl-beta cyclodextrin (M β CD) and filipin, which interfere with cholesterol or lidocaine, significantly inhibited internalization of T. gondii in both cell types, although adhesion remained unaffected in macrophages and decreased only in LLC-MK2 cells. Scanning and transmission electron microscopy confirmed these observations. Results are discussed in terms of the original role of macrophages as professional phagocytes versus the LLC-MK2 cell lineage originated from kidney epithelial cells.

The mathematical cell model reconstructed from interference microscopy data

NASA Astrophysics Data System (ADS)

Rogotnev, A. A.; Nikitiuk, A. S.; Naimark, O. B.; Nebogatikov, V. O.; Grishko, V. V.

2017-09-01

The mathematical model of cell dynamics is developed to link the dynamics of the phase cell thickness with the signs of the oncological pathology. The measurements of irregular oscillations of cancer cells phase thickness were made with laser interference microscope MIM-340 in order to substantiate this model. These data related to the dynamics of phase thickness for different cross-sections of cells (nuclei, nucleolus, and cytoplasm) allow the reconstruction of the attractor of dynamic system. The attractor can be associated with specific types of collective modes of phase thickness responsible for the normal and cancerous cell dynamics. Specific type of evolution operator was determined using an algorithm of designing of the mathematical cell model and temporal phase thickness data for cancerous and normal cells. Qualitative correspondence of attractor types to the cell states was analyzed in terms of morphological signs associated with maximum value of mean square irregular oscillations of phase thickness dynamics.

Cytocompatibility of Direct Laser Interference-patterned Titanium Surfaces for Implants.

PubMed

Hartjen, Philip; Nada, Ola; Silva, Thiago Gundelwein; Precht, Clarissa; Henningsen, Anders; Holthaus, Marzellus GROßE; Gulow, Nikolai; Friedrich, Reinhard E; Hanken, Henning; Heiland, Max; Zwahr, Christoph; Smeets, Ralf; Jung, Ole

2017-01-01

In an effort to generate titanium surfaces for implants with improved osseointegration, we used direct laser interference patterning (DLIP) to modify the surface of pure titanium grade 4 of four different structures. We assessed in vitro cytoxicity and cell attachment, as well as the viability and proliferation of cells cultured directly on the surfaces. Attachment of the cells to the modified surfaces was comparably good compared to that of cells on grit-blasted and acid-etched reference titanium surfaces. In concordance with this, viability and proliferation of the cells directly cultured on the specimens were similar on all the titanium surfaces, regardless of the laser modification, indicating good cytocompatibility. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Ethnicity-Dependent and -Independent Heterogeneity in Healthy Normal Breast Hierarchy Impacts Tumor Characterization

PubMed Central

Nakshatri, Harikrishna; Anjanappa, Manjushree; Bhat-Nakshatri, Poornima

2015-01-01

Recent reports of widespread genetic variation affecting regulation of gene expression raise the possibility of significant inter-individual differences in stem-progenitor-mature cell hierarchy in adult organs. This has not been explored because of paucity of methods to quantitatively assess subpopulation of normal epithelial cells on individual basis. We report the remarkable inter-individual differences in differentiation capabilities as documented by phenotypic heterogeneity in stem-progenitor-mature cell hierarchy of the normal breast. Ethnicity and genetic predisposition are partly responsible for this heterogeneity, evidenced by the finding that CD44+/CD24- and PROCR+/EpCAM- multi-potent stem cells were elevated significantly in African American women compared with Caucasians. ALDEFLUOR+ luminal stem/progenitor cells were lower in BRCA1-mutation carriers compared with cells from healthy donors (p = 0.0014). Moreover, tumor and adjoining-normal breast cells of the same patients showed distinct CD49f+/EpCAM+ progenitor, CD271+/EpCAM- basal, and ALDEFLUOR+ cell profiles. These inter-individual differences in the rate of differentiation in the normal breast may contribute to a substantial proportion of transcriptome, epigenome, and signaling pathway alterations and consequently has the potential to spuriously magnify the extent of documented tumor-specific gene expression. Therefore, comparative analysis of phenotypically defined subpopulations of normal and tumor cells on an individual basis may be required to identify cancer-specific aberrations. PMID:26311223

Ethnicity-Dependent and -Independent Heterogeneity in Healthy Normal Breast Hierarchy Impacts Tumor Characterization.

PubMed

Nakshatri, Harikrishna; Anjanappa, Manjushree; Bhat-Nakshatri, Poornima

2015-08-27

Recent reports of widespread genetic variation affecting regulation of gene expression raise the possibility of significant inter-individual differences in stem-progenitor-mature cell hierarchy in adult organs. This has not been explored because of paucity of methods to quantitatively assess subpopulation of normal epithelial cells on individual basis. We report the remarkable inter-individual differences in differentiation capabilities as documented by phenotypic heterogeneity in stem-progenitor-mature cell hierarchy of the normal breast. Ethnicity and genetic predisposition are partly responsible for this heterogeneity, evidenced by the finding that CD44+/CD24- and PROCR+/EpCAM- multi-potent stem cells were elevated significantly in African American women compared with Caucasians. ALDEFLUOR+ luminal stem/progenitor cells were lower in BRCA1-mutation carriers compared with cells from healthy donors (p = 0.0014). Moreover, tumor and adjoining-normal breast cells of the same patients showed distinct CD49f+/EpCAM+ progenitor, CD271+/EpCAM- basal, and ALDEFLUOR+ cell profiles. These inter-individual differences in the rate of differentiation in the normal breast may contribute to a substantial proportion of transcriptome, epigenome, and signaling pathway alterations and consequently has the potential to spuriously magnify the extent of documented tumor-specific gene expression. Therefore, comparative analysis of phenotypically defined subpopulations of normal and tumor cells on an individual basis may be required to identify cancer-specific aberrations.

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

Gough, Mallory, E-mail: m.gough1@lancaster.ac.uk; Blanthorn-Hazell, Sophee, E-mail: s.blanthorn-hazell@lancaster.ac.uk; Delury, Craig, E-mail: c.delury@lancaster.ac.uk

Highlights: • Copper levels are elevated in the tumour microenvironment. • APP mitigates copper-induced growth inhibition of DU145 prostate cancer (PCa) cells. • The APP intracellular domain is a prerequisite; soluble forms have no effect. • The E1 CuBD of APP is also a prerequisite. • APP copper binding potentially mitigates copper-induced PCa cell growth inhibition. - Abstract: Copper plays an important role in the aetiology and growth of tumours and levels of the metal are increased in the serum and tumour tissue of patients affected by a range of cancers including prostate cancer (PCa). The molecular mechanisms that enablemore » cancer cells to proliferate in the presence of elevated copper levels are, therefore, of key importance in our understanding of tumour growth progression. In the current study, we have examined the role played by the amyloid precursor protein (APP) in mitigating copper-induced growth inhibition of the PCa cell line, DU145. A range of APP molecular constructs were stably over-expressed in DU145 cells and their effects on cell proliferation in the presence of copper were monitored. Our results show that endogenous APP expression was induced by sub-toxic copper concentrations in DU145 cells and over-expression of the wild-type protein was able to mitigate copper-induced growth inhibition via a mechanism involving the cytosolic and E1 copper binding domains of the full-length protein. APP likely represents one of a range of copper binding proteins that PCa cells employ in order to ensure efficient proliferation despite elevated concentrations of the metal within the tumour microenvironment. Targeting the expression of such proteins may contribute to therapeutic strategies for the treatment of cancers.« less

Atomistic molecular dynamics simulations of bioactive engrailed 1 interference peptides (EN1-iPeps).

PubMed

Gandhi, Neha S; Blancafort, Pilar; Mancera, Ricardo L

2018-04-27

The neural-specific transcription factor Engrailed 1 - is overexpressed in basal-like breast tumours. Synthetic interference peptides - comprising a cell-penetrating peptide/nuclear localisation sequence and the Engrailed 1-specific sequence from the N-terminus have been engineered to produce a strong apoptotic response in tumour cells overexpressing EN1, with no toxicity to normal or non Engrailed 1-expressing cells. Here scaled molecular dynamics simulations were used to study the conformational dynamics of these interference peptides in aqueous solution to characterise their structure and dynamics. Transitions from disordered to α-helical conformation, stabilised by hydrogen bonds and proline-aromatic interactions, were observed throughout the simulations. The backbone of the wild-type peptide folds to a similar conformation as that found in ternary complexes of anterior Hox proteins with conserved hexapeptide motifs important for recognition of pre-B-cell leukemia Homeobox 1, indicating that the motif may possess an intrinsic preference for helical structure. The predicted NMR chemical shifts of these peptides are consistent with the Hox hexapeptides in solution and Engrailed 2 NMR data. These findings highlight the importance of aromatic residues in determining the structure of Engrailed 1 interference peptides, shedding light on the rational design strategy of molecules that could be adopted to inhibit other transcription factors overexpressed in other cancer types, potentially including other transcription factor families that require highly conserved and cooperative protein-protein partnerships for biological activity.

EDTA analysis on the Roche MODULAR analyser.

PubMed

Davidson, D F

2007-05-01

Patient specimens can be subject to subtle interference from cross contamination by liquid-based, potassium-containing EDTA anticoagulant, leading to misinterpretation of results. A rapid method for EDTA analysis to detect such contamination is described. An in-house EDTA assay on the Roche MODULAR analyser was assessed for accuracy and precision by comparison with an adjusted calcium difference measurement (atomic absorption and o-cresolphthalein complexone colorimetry). EDTA method versus adjusted calcium difference showed: slope = 1.038 (95% confidence interval [CI] 0.949-1.131); intercept = 0.073 (95% CI 0.018-0.132) mmol/L; r = 0.914; n = 94. However, inter-assay precision of the calcium difference method was estimated to be poorer (coefficient of variation 24.8% versus 3.4% for the automated colorimetric method at an EDTA concentration of 0.25 mmol/L). Unequivocal contamination was observed at an EDTA concentration of > or =0.2 mmol/L. The automated method showed positive interference from haemolysis and negative interference from oxalate. The method was unaffected by lipaemia (triglycerides <20 mmol/L), icterus (bilirubin <500 micromol/L), glucose (<100 mmol/L), iron (<100 micromol/L), and citrate, phosphate or fluoride (all <2.5 mmol/L). The automated colorimetric assay described is an accurate, precise and rapid (3 min) means of detecting EDTA contamination of unhaemolysed biochemistry specimens.

Calling louder and longer: how bats use biosonar under severe acoustic interference from other bats

PubMed Central

Amichai, Eran; Blumrosen, Gaddi; Yovel, Yossi

2015-01-01

Active-sensing systems such as echolocation provide animals with distinct advantages in dark environments. For social animals, however, like many bat species, active sensing can present problems as well: when many individuals emit bio-sonar calls simultaneously, detecting and recognizing the faint echoes generated by one's own calls amid the general cacophony of the group becomes challenging. This problem is often termed ‘jamming’ and bats have been hypothesized to solve it by shifting the spectral content of their calls to decrease the overlap with the jamming signals. We tested bats’ response in situations of extreme interference, mimicking a high density of bats. We played-back bat echolocation calls from multiple speakers, to jam flying Pipistrellus kuhlii bats, simulating a naturally occurring situation of many bats flying in proximity. We examined behavioural and echolocation parameters during search phase and target approach. Under severe interference, bats emitted calls of higher intensity and longer duration, and called more often. Slight spectral shifts were observed but they did not decrease the spectral overlap with jamming signals. We also found that pre-existing inter-individual spectral differences could allow self-call recognition. Results suggest that the bats’ response aimed to increase the signal-to-noise ratio and not to avoid spectral overlap. PMID:26702045

Calling louder and longer: how bats use biosonar under severe acoustic interference from other bats.

PubMed

Amichai, Eran; Blumrosen, Gaddi; Yovel, Yossi

2015-12-22

Active-sensing systems such as echolocation provide animals with distinct advantages in dark environments. For social animals, however, like many bat species, active sensing can present problems as well: when many individuals emit bio-sonar calls simultaneously, detecting and recognizing the faint echoes generated by one's own calls amid the general cacophony of the group becomes challenging. This problem is often termed 'jamming' and bats have been hypothesized to solve it by shifting the spectral content of their calls to decrease the overlap with the jamming signals. We tested bats' response in situations of extreme interference, mimicking a high density of bats. We played-back bat echolocation calls from multiple speakers, to jam flying Pipistrellus kuhlii bats, simulating a naturally occurring situation of many bats flying in proximity. We examined behavioural and echolocation parameters during search phase and target approach. Under severe interference, bats emitted calls of higher intensity and longer duration, and called more often. Slight spectral shifts were observed but they did not decrease the spectral overlap with jamming signals. We also found that pre-existing inter-individual spectral differences could allow self-call recognition. Results suggest that the bats' response aimed to increase the signal-to-noise ratio and not to avoid spectral overlap. © 2015 The Author(s).

Differential effects of non-informative vision and visual interference on haptic spatial processing

PubMed Central

van Rheede, Joram J.; Postma, Albert; Kappers, Astrid M. L.

2008-01-01

The primary purpose of this study was to examine the effects of non-informative vision and visual interference upon haptic spatial processing, which supposedly derives from an interaction between an allocentric and egocentric reference frame. To this end, a haptic parallelity task served as baseline to determine the participant-dependent biasing influence of the egocentric reference frame. As expected, large systematic participant-dependent deviations from veridicality were observed. In the second experiment we probed the effect of non-informative vision on the egocentric bias. Moreover, orienting mechanisms (gazing directions) were studied with respect to the presentation of haptic information in a specific hemispace. Non-informative vision proved to have a beneficial effect on haptic spatial processing. No effect of gazing direction or hemispace was observed. In the third experiment we investigated the effect of simultaneously presented interfering visual information on the haptic bias. Interfering visual information parametrically influenced haptic performance. The interplay of reference frames that subserves haptic spatial processing was found to be related to both the effects of non-informative vision and visual interference. These results suggest that spatial representations are influenced by direct cross-modal interactions; inter-participant differences in the haptic modality resulted in differential effects of the visual modality. PMID:18553074

Knockdown of CkrL by shRNA deteriorates hypoxia/reoxygenation-induced H9C2 cardiomyocyte apoptosis and survival inhibition Via Bax and downregulation of P-Erk1/2.

PubMed

Zhang, Zhi-Sheng; Yang, Dong-Yan; Fu, Yan-Bo; Zhang, Lei; Zhao, Qian-Ping; Li, Gang

2015-03-01

Integrin β1 subunit and its downstream molecule integrin-linked kinase and focal adhesion kinase have been confirmed to be essential to cell survival and inhibition of apoptosis and hypoxia/reoxygenation (H/R)-induced injuries in cardiomyocytes. However, it is still unclear whether CrkL [v-crk avian sarcoma virus CT-10 oncogene homolog (Crk)-like], which acts also as a component of the integrin pathway, could also affect H/R-induced injuries in the cardiomyocytes. The rat-derived H9C2 cardiomyocytes were infected with a CrkL small hairpin RNA interference recombinant lentivirus, which knockdowns the endogenous CrkL expression in the cardiomyocytes. Apoptosis, cell proliferation and survival were examined in the H9C2 cardiomyocytes treated with either H/R or not. Results showed that knockdown of CrkL could significantly increase apoptosis and inhibition of the cell proliferation and survival and deteriorate the previously mentioned injuries induced by H/R. In contrast, overexpression of human CrkL could relieve the exacerbation of the previously mentioned injuries induced by CrkL knockdown in the H9C2 cardiomyocytes via regulation of Bax and extracellular signal-regulated kinase1/2 (p-ERK1/2). In conclusion, these results confirmed that knockdown of CrkL could deteriorate H/R-induced apoptosis and cell survival inhibition in rat-derived H9C2 cardiomyocytes via Bax and downregulation of p-ERK1/2. It implies that CrkL could mitigate H/R-induced injuries in the cardiomyocytes. Copyright © 2015 John Wiley & Sons, Ltd.

Cellular chromosome DNA interferes with fluorescence quantitative real-time PCR detection of HBV DNA in culture medium.

PubMed

Pan, Xiao-Ben; Wei, Lai; Han, Jin-Chao; Gao, Yan

2008-01-01

Fluorescence quantitative real-time PCR (FQ-PCR) is a recently developed technique increasingly used for clinical diagnosis by detection of hepatitis B virus (HBV) DNA in serum. FQ-PCR is also used in scientific research for detection of HBV DNA in cell culture. Understanding potential FQ-PCR interference factors can improve the accuracy of HBV DNA quantification in cell culture medium. HBV positive serum was diluted with culture medium to produce three test groups with HBV DNA levels of 5 x 10(7) copies/ml (high), 5 x 10(5) copies/ml (medium), and 5 x 10(3) copies/ml (low). Chromosome DNA was extracted from HepG2 cells and then added to high, medium, and low group samples at final concentrations of 0, 12.5, 25, 50, and 100 microg/ml. The samples were quantified by FQ-PCR and data were evaluated using statistical software. No marked changes were seen in the quantitative curves for high level HBV DNA samples when the samples were supplemented with 0-100 microg/ml of chromosome DNA. Interference was observed in medium level samples when 50 and 100 microg/ml of chromosome DNA was added. Interference was also observed in low level HBV DNA samples when the concentration of added chromosome DNA was greater than 25 microg/ml. The interference was eliminated when samples were digested by DNase I prior to PCR detection. In Conclusions, the presence of cellular chromosome DNA can interfere with the detection of HBV DNA by FQ-PCR. Removal of cellular chromosome DNA from culture media prior to FQ-PCR is necessary for reliable HBV DNA quantitative detection. (c) 2007 Wiley-Liss, Inc.

Stromal Progenitor Cells in Mitigation of Non-Hematopoietic Radiation Injuries

PubMed Central

Kulkarni, Shilpa; Wang, Timothy C.; Guha, Chandan

2016-01-01

Purpose of review Therapeutic exposure to high doses of radiation can severely impair organ function due to ablation of stem cells. Normal tissue injury is a dose-limiting toxicity for radiation therapy (RT). Although advances in the delivery of high precision conformal RT has increased normal tissue sparing, mitigating and therapeutic strategies that could alleviate early and chronic radiation effects are urgently needed in order to deliver curative doses of RT, especially in abdominal, pelvic and thoracic malignancies. Radiation-induced gastrointestinal injury is also a major cause of lethality from accidental or intentional exposure to whole body irradiation in the case of nuclear accidents or terrorism. This review examines the therapeutic options for mitigation of non-hematopoietic radiation injuries. Recent findings We have developed stem cell based therapies for the mitigation of acute radiation syndrome (ARS) and radiation-induced gastrointestinal syndrome (RIGS). This is a promising option because of the robustness of standardized isolation and transplantation of stromal cells protocols, and their ability to support and replace radiation-damaged stem cells and stem cell niche. Stromal progenitor cells (SPC) represent a unique multipotent and heterogeneous cell population with regenerative, immunosuppressive, anti-inflammatory, and wound healing properties. SPC are also known to secrete various key cytokines and growth factors such as platelet derived growth factors (PDGF), keratinocyte growth factor (KGF), R-spondins (Rspo), and may consequently exert their regenerative effects via paracrine function. Additionally, secretory vesicles such as exosomes or microparticles can potentially be a cell-free alternative replacing the cell transplant in some cases. Summary This review highlights the beneficial effects of SPC on tissue regeneration with their ability to (a) target the irradiated tissues, (b) recruit host stromal cells, (c) regenerate endothelium and epithelium, (d) and secrete regenerative and immunomodulatory paracrine signals to control inflammation, ulceration, wound healing and fibrosis. PMID:28462013

Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response

PubMed Central

Busch, Andrea W.U.; Montgomery, Beronda L.

2015-01-01

Tetrapyrroles are involved in light harvesting and light perception, electron-transfer reactions, and as co-factors for key enzymes and sensory proteins. Under conditions in which cells exhibit stress-induced imbalances of photosynthetic reactions, or light absorption exceeds the ability of the cell to use photoexcitation energy in synthesis reactions, redox imbalance can occur in photosynthetic cells. Such conditions can lead to the generation of reactive oxygen species (ROS) associated with alterations in tetrapyrrole homeostasis. ROS accumulation can result in cellular damage and detrimental effects on organismal fitness, or ROS molecules can serve as signals to induce a protective or damage-mitigating oxidative stress signaling response in cells. Induced oxidative stress responses include tetrapyrrole-dependent and -independent mechanisms for mitigating ROS generation and/or accumulation. Thus, tetrapyrroles can be contributors to oxidative stress, but are also essential in the oxidative stress response to protect cells by contributing to detoxification of ROS. In this review, we highlight the interconnection and interdependence of tetrapyrrole metabolism with the occurrence of oxidative stress and protective oxidative stress signaling responses in photosynthetic organisms. PMID:25618582

Decoupled Modulation Control

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

Wang, Shaobu; Huang, Renke; Huang, Zhenyu

The objective of this research work is to develop decoupled modulation control methods for damping inter-area oscillations with low frequencies, so the damping control can be more effective and easier to design with less interference among different oscillation modes in the power system. A signal-decoupling algorithm was developed that can enable separation of multiple oscillation frequency contents and extraction of a “pure” oscillation frequency mode that are fed into Power System Stabilizers (PSSs) as the modulation input signals. As a result, instead of introducing interferences between different oscillation modes from the traditional approaches, the output of the new PSS modulationmore » control signal mainly affects only one oscillation mode of interest. The new decoupled modulation damping control algorithm has been successfully developed and tested on the standard IEEE 4-machine 2-area test system and a minniWECC system. The results are compared against traditional modulation controls, which demonstrates the validity and effectiveness of the newly-developed decoupled modulation damping control algorithm.« less

Comparison of digital signal-signal beat interference compensation techniques in direct-detection subcarrier modulation systems.

PubMed

Li, Zhe; Erkilinc, M Sezer; Galdino, Lidia; Shi, Kai; Thomsen, Benn C; Bayvel, Polina; Killey, Robert I

2016-12-12

Single-polarization direct-detection transceivers may offer advantages compared to digital coherent technology for some metro, back-haul, access and inter-data center applications since they offer low-cost and complexity solutions. However, a direct-detection receiver introduces nonlinearity upon photo detection, since it is a square-law device, which results in signal distortion due to signal-signal beat interference (SSBI). Consequently, it is desirable to develop effective and low-cost SSBI compensation techniques to improve the performance of such transceivers. In this paper, we compare the performance of a number of recently proposed digital signal processing-based SSBI compensation schemes, including the use of single- and two-stage linearization filters, an iterative linearization filter and a SSBI estimation and cancellation technique. Their performance is assessed experimentally using a 7 × 25 Gb/s wavelength division multiplexed (WDM) single-sideband 16-QAM Nyquist-subcarrier modulation system operating at a net information spectral density of 2.3 (b/s)/Hz.

Sharing possibilities amongst CDMA Mobile Satellite Systems, and impacts of terminal characteristics on sharing

NASA Astrophysics Data System (ADS)

Bambace, Luís Antonio Waack; Ceballos, Décio Castilho

CDMA Mobile Satellite Systems (CDMA MSS) are able to co-directional, co-frequency and co-coverage sharing, and they are strongly interdependent in case of such a sharing. It is also known that the success of any telecommunication project is the use of the correct media to each task. Operators have a clear sight of such a media adequacy in traditional systems, but not necessarily in the case of Mobile Satellite Systems. This creates a risk that a wrong market objective operator causes trouble to other systems. This paper deals with the sharing alternatives for up to four CDMA MSS operating in the same frequency band, and analysts both: satellite to user downlink and user to satellite uplink. The influence of several items in capacity is here treated. The scope includes: downlink power flux density: code availability; single system internal interference; inter-system interference; diversity schemes: average link impairments, margins; user cooperation; terminal specifications and the dependence of the insulation between RHCP and LHCP with fade.

Examination of the potential for adaptive chirality of the nitrogen chiral center in aza-aspartame.

PubMed

Bouayad-Gervais, Samir H; Lubell, William D

2013-11-28

The potential for dynamic chirality of an azapeptide nitrogen was examined by substitution of nitrogen for the α-carbon of the aspartate residue in the sweetener S,S-aspartame. Considering that S,S- and R,S-aspartame possess sweet and bitter tastes, respectively, a bitter-sweet taste of aza-aspartame 9 could be indicative of a low isomerization barrier for nitrogen chirality inter-conversion. Aza-aspartame 9 was synthesized by a combination of hydrazine and peptide chemistry. Crystallization of 9 indicated a R,S-configuration in the solid state; however, the aza-residue chiral center was considerably flattened relative to its natural amino acid counterpart. On tasting, the authors considered aza-aspartame 9 to be slightly bitter or tasteless. The lack of bitter sweet taste of aza-aspartame 9 may be due to flattening from sp2 hybridization in the urea as well as a high barrier for sp3 nitrogen inter-conversion, both of which may interfere with recognition by taste receptors.

Cell nuclei segmentation in fluorescence microscopy images using inter- and intra-region discriminative information.

PubMed

Song, Yang; Cai, Weidong; Feng, David Dagan; Chen, Mei

2013-01-01

Automated segmentation of cell nuclei in microscopic images is critical to high throughput analysis of the ever increasing amount of data. Although cell nuclei are generally visually distinguishable for human, automated segmentation faces challenges when there is significant intensity inhomogeneity among cell nuclei or in the background. In this paper, we propose an effective method for automated cell nucleus segmentation using a three-step approach. It first obtains an initial segmentation by extracting salient regions in the image, then reduces false positives using inter-region feature discrimination, and finally refines the boundary of the cell nuclei using intra-region contrast information. This method has been evaluated on two publicly available datasets of fluorescence microscopic images with 4009 cells, and has achieved superior performance compared to popular state of the art methods using established metrics.

CENP-E Kinesin Interacts with SKAP Protein to Orchestrate Accurate Chromosome Segregation in Mitosis*

PubMed Central

Huang, Yuejia; Wang, Wenwen; Yao, Phil; Wang, Xiwei; Liu, Xing; Zhuang, Xiaoxuan; Yan, Feng; Zhou, Jinhua; Du, Jian; Ward, Tarsha; Zou, Hanfa; Zhang, Jiancun; Fang, Guowei; Ding, Xia; Dou, Zhen; Yao, Xuebiao

2012-01-01

Mitotic chromosome segregation is orchestrated by the dynamic interaction of spindle microtubules with the kinetochore. Although previous studies show that the mitotic kinesin CENP-E forms a link between attachment of the spindle microtubule to the kinetochore and the mitotic checkpoint signaling cascade, the molecular mechanism underlying dynamic kinetochore-microtubule interactions in mammalian cells remains elusive. Here, we identify a novel interaction between CENP-E and SKAP that functions synergistically in governing dynamic kinetochore-microtubule interactions. SKAP binds to the C-terminal tail of CENP-E in vitro and is essential for an accurate kinetochore-microtubule attachment in vivo. Immunoelectron microscopic analysis indicates that SKAP is a constituent of the kinetochore corona fibers of mammalian centromeres. Depletion of SKAP or CENP-E by RNA interference results in a dramatic reduction of inter-kinetochore tension, which causes chromosome mis-segregation with a prolonged delay in achieving metaphase alignment. Importantly, SKAP binds to microtubules in vitro, and this interaction is synergized by CENP-E. Based on these findings, we propose that SKAP cooperates with CENP-E to orchestrate dynamic kinetochore-microtubule interaction for faithful chromosome segregation. PMID:22110139

Sequencing of Single Pollen Nuclei Reveals Meiotic Recombination Events at Megabase Resolution and Circumvents Segregation Distortion Caused by Postmeiotic Processes

PubMed Central

Dreissig, Steven; Fuchs, Jörg; Himmelbach, Axel; Mascher, Martin; Houben, Andreas

2017-01-01

Meiotic recombination is a fundamental mechanism to generate novel allelic combinations which can be harnessed by breeders to achieve crop improvement. The recombination landscape of many crop species, including the major crop barley, is characterized by a dearth of recombination in 65% of the genome. In addition, segregation distortion caused by selection on genetically linked loci is a frequent and undesirable phenomenon in double haploid populations which hampers genetic mapping and breeding. Here, we present an approach to directly investigate recombination at the DNA sequence level by combining flow-sorting of haploid pollen nuclei of barley with single-cell genome sequencing. We confirm the skewed distribution of recombination events toward distal chromosomal regions at megabase resolution and show that segregation distortion is almost absent if directly measured in pollen. Furthermore, we show a bimodal distribution of inter-crossover distances, which supports the existence of two classes of crossovers which are sensitive or less sensitive to physical interference. We conclude that single pollen nuclei sequencing is an approach capable of revealing recombination patterns in the absence of segregation distortion. PMID:29018459

IRCI-Free MIMO-OFDM SAR Using Circularly Shifted Zadoff-Chu Sequences

NASA Astrophysics Data System (ADS)

Cao, Yun-He; Xia, Xiang-Gen

2015-05-01

Cyclic prefix (CP) based MIMO-OFDM radar has been recently proposed for distributed transmit antennas, where there is no inter-range-cell interference (IRCI). It can collect full spatial diversity and each transmitter transmits signals with the same frequency band, i.e., the range resolution is not reduced. However, it needs to transmit multiple OFDM pulses consecutively to obtain range profiles for a single swath, which may be too long in time for a reasonable swath width. In this letter, we propose a CP based MIMO-OFDM synthetic aperture radar (SAR) system, where each transmitter transmits only a single OFDM pulse to obtain range profiles for a swath and has the same frequency band, thus the range resolution is not reduced. It is IRCI free and can collect the full spatial diversity if the transmit antennas are distributed. Our main idea is to use circularly shifted Zadoff-Chu sequences as the weighting coefficients in the OFDM pulses for different transmit antennas and apply spatial filters with multiple receive antennas to divide the whole swath into multiple subswaths, and then each subswath is reconstructed/imaged using our proposed IRCI free range reconstruction method.

Argonaute2 and LaminB modulate gene expression by controlling chromatin topology

PubMed Central

Nazer, Ezequiel; Dale, Ryan K.; Chinen, Madoka; Radmanesh, Behram

2018-01-01

Drosophila Argonaute2 (AGO2) has been shown to regulate expression of certain loci in an RNA interference (RNAi)-independent manner, but its genome-wide function on chromatin remains unknown. Here, we identified the nuclear scaffolding protein LaminB as a novel interactor of AGO2. When either AGO2 or LaminB are depleted in Kc cells, similar transcription changes are observed genome-wide. In particular, changes in expression occur mainly in active or potentially active chromatin, both inside and outside LaminB-associated domains (LADs). Furthermore, we identified a somatic target of AGO2 transcriptional repression, no hitter (nht), which is immersed in a LAD located within a repressive topologically-associated domain (TAD). Null mutation but not catalytic inactivation of AGO2 leads to ectopic expression of nht and downstream spermatogenesis genes. Depletion of either AGO2 or LaminB results in reduced looping interactions within the nht TAD as well as ectopic inter-TAD interactions, as detected by 4C-seq analysis. Overall, our findings reveal coordination of AGO2 and LaminB function to dictate genome architecture and thereby regulate gene expression. PMID:29529026

[Assessment of lipid layer thickness of tear film in the diagnosis of dry-eye syndrome in children after the hematopoietic stem cell transplantation].

PubMed

Kurpińska, Małgorzata; Gorczyńska, Ewa; Owoc-Lempach, Joanna; Bernacka, Aleksandra; Misiuk-Hojło, Marta; Chybicka, Alicja

2011-01-01

Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS) is recognized as the most frequent ocular complication after allogeneic stem cell transplantation (allo-SCT). KCS can appear either due to insufficient tear production or excessive tear evaporation, both resulting in tears hyperosmolarity that leads to ocular damage. The evaporation rate and better film stability is determined primarily by the status of the lipid layer. Observation and classification of tear film lipid layer interference patterns in normal and dry eyes in patients after allogeneic stem cell transplantation with a follow-up time of 6 months-5 years (median 26.54 months). Investigation of the relation between the lipid layer interference patterns in normal and dry eyes and the results of other dry eye examinations and complaints. Relation between DES and conditioning regimes, including total body irradiation and high-dose chemotherapy, immunosuppressive drugs, the time after allogeneic stem cell transplantation and chronic graft-versus-host disease. Precorneal tears lipid layer interference patterns, were examined in 114 eyes in treatment group with the Tearscope-plus. Patient with dry eye were identified on the basis of Schirmer test scores and/or tear breakup time, and positive lissamine and/or fluorescein staining. 42 of 114 eyes (36.8%) developed DES after allo-SCT A significant correlation between thickness of lipid layer and BUT, Schirmer test, lissamine green and fluorescein staining was found in the treatment group. A significant association was found between present chronic GVHD and DES in children. DES was not associated with TBI, corticosteroids, immunosuppressive drugs and the time in the present study. Tears lipid layer interference patterns are highly correlated with the diagnosis of DES. Tears lipid layer interference patterns ( noninvasive method), can be used to diagnose early DES in children after allo-SCT. Chronic GVHD play a major role in development of DES. dry eye syndrome, graft versus host disease, stem cell transplantation.

RNA targeting with CRISPR-Cas13.

PubMed

Abudayyeh, Omar O; Gootenberg, Jonathan S; Essletzbichler, Patrick; Han, Shuo; Joung, Julia; Belanto, Joseph J; Verdine, Vanessa; Cox, David B T; Kellner, Max J; Regev, Aviv; Lander, Eric S; Voytas, Daniel F; Ting, Alice Y; Zhang, Feng

2017-10-12

RNA has important and diverse roles in biology, but molecular tools to manipulate and measure it are limited. For example, RNA interference can efficiently knockdown RNAs, but it is prone to off-target effects, and visualizing RNAs typically relies on the introduction of exogenous tags. Here we demonstrate that the class 2 type VI RNA-guided RNA-targeting CRISPR-Cas effector Cas13a (previously known as C2c2) can be engineered for mammalian cell RNA knockdown and binding. After initial screening of 15 orthologues, we identified Cas13a from Leptotrichia wadei (LwaCas13a) as the most effective in an interference assay in Escherichia coli. LwaCas13a can be heterologously expressed in mammalian and plant cells for targeted knockdown of either reporter or endogenous transcripts with comparable levels of knockdown as RNA interference and improved specificity. Catalytically inactive LwaCas13a maintains targeted RNA binding activity, which we leveraged for programmable tracking of transcripts in live cells. Our results establish CRISPR-Cas13a as a flexible platform for studying RNA in mammalian cells and therapeutic development.

Wave interference: mechanics of the standing wave component and the illusion of "which way" information

NASA Astrophysics Data System (ADS)

Hudgins, W. R.; Meulenberg, A.; Penland, R. F.

2015-09-01

Two adjacent coherent light beams, 180° out of phase and traveling on adjacent, parallel paths, remain visibly separated by the null (dark) zone from their mutual interference pattern as they merge. Each half of the pattern can be traced to one of the beams. Does such an experiment provide both "which way" and momentum knowledge? To answer this question, we demonstrate, by examining behavior of wave momentum and energy in a medium, that interfering waves interact. Central to the mechanism of interference is a standing wave component resulting from the combination of coherent waves. We show the mathematics for the formation of the standing wave component and for wave momentum involved in the waves' interaction. In water and in open coaxial cable, we observe that standing waves form cells bounded "reflection zones" where wave momentum from adjacent cells is reversed, confining oscillating energy to each cell. Applying principles observed in standing waves in media to the standing wave component of interfering light beams, we identify dark (null) regions to be the reflection zones. Each part of the interference pattern is affected by interactions between other parts, obscuring "which-way" information. We demonstrated physical interaction experimentally using two beams interfering slightly with one dark zone between them. Blocking one beam "downstream" from the interference region removed the null zone and allowed the remaining beam to evolve to a footprint of a single beam.

Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

DOEpatents

Brown, Edward J.; Baldasaro, Paul F.; Dziendziel, Randolph J.

1997-01-01

A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength .lambda..sub.IF approximately equal to the bandgap wavelength .lambda..sub.g of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5.lambda..sub.IF to .lambda..sub.IF and reflect from .lambda..sub.IF to about 2.lambda..sub.IF ; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5.lambda..sub.IF.

Reduction of polyatomic interferences in ICP-MS by collision/reaction cell (CRC-ICP-MS) techniques

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

Eiden, Greg C; Barinaga, Charles J; Koppenaal, David W

2012-05-01

Polyatomic and other spectral interferences in plasma source mass spectrometry (PSMS) can be dramatically reduced using collision and reaction cells (CRC). These devices have been used for decades in fundamental studies of ion-molecule chemistry, but have only recently been applied to PSMS. Benefits of this approach as applied in inductively coupled plasma MS (ICP-MS) include interference reduction, isobar separation, and thermalization/focusing of ions. Novel ion-molecule chemistry schemes are now routinely designed and empirically evaluated with relative ease. These “chemical resolution” techniques can avert interferences requiring mass spectral resolutions of >600,000 (m/m). Purely physical ion beam processes, including collisional dampening andmore » collisional dissociation, are also employed to provide improved sensitivity, resolution, and spectral simplicity. CRC techniques are now firmly entrenched in current-day ICP-MS technology, enabling unprecedented flexibility and freedom from many spectral interferences. A significant body of applications has now been reported in the literature. CRC techniques are found to be most useful for specialized or difficult analytical needs and situations, and are employed in both single- and multi-element determination modes.« less

Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 1): Development of theoretical models for design considerations.

PubMed

Sahoo, B K; Sudeep Kumara, K; Karunakara, N; Gaware, J J; Sapra, B K; Mayya, Y S

2017-06-01

Regulating the environmental discharge of 220 Rn (historically known as thoron) and its decay products from thorium processing facilities is important for protection of environment and general public living in the vicinities. Activated charcoal provides an effective solution to this problem because of its high adsorption capacity to gaseous element like radon. In order to design and develop a charcoal based Thoron Mitigation System, a mathematical model has been developed in the present work for studying the 220 Rn transport and adsorption in a flow through charcoal bed and estimating the 220 Rn mitigation factor (MF) as a function of system and operating parameters. The model accounts for inter- and intra-grain diffusion, advection, radioactive decay and adsorption processes. Also, the effects of large void fluctuation and wall channeling on the mitigation factor have been included through a statistical model. Closed form solution has been provided for the MF in terms of adsorption coefficient, system dimensions, grain size, flow rate and void fluctuation exponent. It is shown that the delay effects due to intra grain diffusion plays a significant role thereby rendering external equilibrium assumptions unsuitable. Also, the application of the statistical model clearly demonstrates the transition from the exponential MF to a power-law form and shows how the occurrence of channels with low probability can lower mitigation factor by several orders of magnitude. As a part of aiding design, the model is further extended to optimise the bed dimensions in respect of pressure drop and MF. The application of the results for the design and development of a practically useful charcoal bed is discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biology of lung cancer: genetic mutation, epithelial-mesenchymal transition, and cancer stem cells.

PubMed

Aoi, Takashi

2016-09-01

At present, most cases of unresectable cancer cannot be cured. Genetic mutations, EMT, and cancer stem cells are three major issues linked to poor prognosis in such cases, all connected by inter- and intra-tumor heterogeneity. Issues on inter-/intra-tumor heterogeneity of genetic mutation could be resolved with recent and future technologies of deep sequencers, whereas, regarding such issues as the "same genome, different epigenome/phenotype", we expect to solve many of these problems in the future through further research in stem cell biology. We herein review and discuss the three major issues in the biology of cancers, especially from the standpoint of stem cell biology.

Haemophilus haemolyticus Interaction with Host Cells Is Different to Nontypeable Haemophilus influenzae and Prevents NTHi Association with Epithelial Cells

PubMed Central

Pickering, Janessa L.; Prosser, Amy; Corscadden, Karli J.; de Gier, Camilla; Richmond, Peter C.; Zhang, Guicheng; Thornton, Ruth B.; Kirkham, Lea-Ann S.

2016-01-01

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that resides in the upper respiratory tract and contributes to a significant burden of respiratory related diseases in children and adults. Haemophilus haemolyticus is a respiratory tract commensal that can be misidentified as NTHi due to high levels of genetic relatedness. There are reports of invasive disease from H. haemolyticus, which further blurs the species boundary with NTHi. To investigate differences in pathogenicity between these species, we optimized an in vitro epithelial cell model to compare the interaction of 10 H. haemolyticus strains with 4 NTHi and 4 H. influenzae-like haemophili. There was inter- and intra-species variability but overall, H. haemolyticus had reduced capacity to attach to and invade nasopharyngeal and bronchoalveolar epithelial cell lines (D562 and A549) within 3 h when compared with NTHi. H. haemolyticus was cytotoxic to both cell lines at 24 h, whereas NTHi was not. Nasopharyngeal epithelium challenged with some H. haemolyticus strains released high levels of inflammatory mediators IL-6 and IL-8, whereas NTHi did not elicit an inflammatory response despite higher levels of cell association and invasion. Furthermore, peripheral blood mononuclear cells stimulated with H. haemolyticus or NTHi released similar and high levels of IL-6, IL-8, IL-10, IL-1β, and TNFα when compared with unstimulated cells but only NTHi elicited an IFNγ response. Due to the relatedness of H. haemolyticus and NTHi, we hypothesized that H. haemolyticus may compete with NTHi for colonization of the respiratory tract. We observed that in vitro pre-treatment of epithelial cells with H. haemolyticus significantly reduced NTHi attachment, suggesting interference or competition between the two species is possible and warrants further investigation. In conclusion, H. haemolyticus interacts differently with host cells compared to NTHi, with different immunostimulatory and cytotoxic properties. This study provides an in vitro model for further investigation into the pathogenesis of Haemophilus species and the foundation for exploring whether H. haemolyticus can be used to prevent NTHi disease. PMID:27242968

Interference of a synthetic C18 juvenile hormone with mammalian cells in vitro, I. Effects on growth and morphology.

PubMed

Zielińska, Z M; Laskowska-Bozek, H; Jastreboff, P

1978-01-01

Some of structural and functional analogs of juvenile hormones are now under field examinations as growth inhibitors of some pest-insect populations. So far however very little is known about the possible interference of these compounds with mammalian cells or organisms. In this research the interference of a synthetic preparation of the insect C18 juvenile hormone with mouse embryo fibroblasts (ME-cells) and mouse cells of an established line (L-cells) was studied. Aliquots of juvenile hormone solution or those of the solvent (DMSO plus ethanol, 9:1) were included into the culture medium and after defined times of contact the cells were tested for their morphology, pattern of growth, proliferation rate and viability. The data for the parameters under examination were evaluated by means of the analysis of variance and checked by the Tuckey test. The sensitivity of ME-cells and L-cells to the agent tested was compared by means of the analysis of variance of the data for mitotic indices of these cells and by evaluation of the number of dead cells in cultures under the particular conditions of the experiments. The main findings can be summarized as follows: 1. Cells of both types are evidently more sensitive to juvenile hormone than to the solvent. 2. ME-cells are more sensitive to both agents than are L-cells. 3. The concentrations of the hormone in the medium required to evoked the cytocidal effect on the mouse cells similarly as those affecting some insect non-target cells were far above concentrations found in insect blood, but they were of the same order of magnitude as those used in physiological experiments with insect organs in vitro.

Topography and refractometry of sperm cells using spatial light interference microscopy

NASA Astrophysics Data System (ADS)

Liu, Lina; Kandel, Mikhail E.; Rubessa, Marcello; Schreiber, Sierra; Wheeler, Mathew B.; Popescu, Gabriel

2018-02-01

Characterization of spermatozoon viability is a common test in treating infertility. Recently, it has been shown that label-free, phase-sensitive imaging can provide a valuable alternative for this type of assay. We employ spatial light interference microscopy (SLIM) to perform high-accuracy single-cell phase imaging and decouple the average thickness and refractive index information for the population. This procedure was enabled by quantitative-phase imaging cells on media of two different refractive indices and using a numerical tool to remove the curvature from the cell tails. This way, we achieved ensemble averaging of topography and refractometry of 100 cells in each of the two groups. The results show that the thickness profile of the cell tail goes down to 150 nm and the refractive index can reach values of 1.6 close to the head.

Study of morphological changes in breast cancer cells MCF-7 under the action of pro-apoptotic agents with laser modulation interference microscope MIM-340

NASA Astrophysics Data System (ADS)

Nebogatikov, V.; Nikitiuk, A.; Konysheva, A.; Ignatyev, P.; Grishko, V.; Naimark, O.

2017-09-01

Quantitative phase microscopy is a new method to measure and evaluate the microlevel processes characterized by the high resolution and providing ample opportunities to quantitatively analyze various parameters, including specimens from biological matter. In this study, a laser interference microscope was used to evaluate the state of cancer cells (living and apoptotic). Apoptotic cancer cells were obtained by treatment of MCF-7 cells with the use of betulin-based α-bromomethyl ketone (BMK) derivative. When using the microscope, the main differences in the morphometric parameters of living and apoptotic cells such as height, diameter, perimeter, area and volume were appraised. The criteria that can be used as markers of apoptosis activation were identified.

Investigating the Consequences of Interference between Multiple CD8+ T Cell Escape Mutations in Early HIV Infection

PubMed Central

Garcia, Victor; Feldman, Marcus W.; Regoes, Roland R.

2016-01-01

During early human immunodeficiency virus (HIV) infection multiple CD8+ T cell responses are elicited almost simultaneously. These responses exert strong selective pressures on different parts of HIV’s genome, and select for mutations that escape recognition and are thus beneficial to the virus. Some studies reveal that the later these escape mutations emerge, the more slowly they go to fixation. This pattern of escape rate decrease(ERD) can arise by distinct mechanisms. In particular, in large populations with high beneficial mutation rates interference among different escape strains –an effect that can emerge in evolution with asexual reproduction and results in delayed fixation times of beneficial mutations compared to sexual reproduction– could significantly impact the escape rates of mutations. In this paper, we investigated how interference between these concurrent escape mutations affects their escape rates in systems with multiple epitopes, and whether it could be a source of the ERD pattern. To address these issues, we developed a multilocus Wright-Fisher model of HIV dynamics with selection, mutation and recombination, serving as a null-model for interference. We also derived an interference-free null model assuming initial neutral evolution before immune response elicitation. We found that interference between several equally selectively advantageous mutations can generate the observed ERD pattern. We also found that the number of loci, as well as recombination rates substantially affect ERD. These effects can be explained by the underexponential decline of escape rates over time. Lastly, we found that the observed ERD pattern in HIV infected individuals is consistent with both independent, interference-free mutations as well as interference effects. Our results confirm that interference effects should be considered when analyzing HIV escape mutations. The challenge in estimating escape rates and mutation-associated selective coefficients posed by interference effects cannot simply be overcome by improved sampling frequencies or sizes. This problem is a consequence of the fundamental shortcomings of current estimation techniques under interference regimes. Hence, accounting for the stochastic nature of competition between mutations demands novel estimation methodologies based on the analysis of HIV strains, rather than mutation frequencies. PMID:26829720

A Reliable Data Transmission Model for IEEE 802.15.4e Enabled Wireless Sensor Network under WiFi Interference.

PubMed

Sahoo, Prasan Kumar; Pattanaik, Sudhir Ranjan; Wu, Shih-Lin

2017-06-07

The IEEE 802.15.4e standard proposes Medium Access Control (MAC) to support collision-free wireless channel access mechanisms for industrial, commercial and healthcare applications. However, unnecessary wastage of energy and bandwidth consumption occur due to inefficient backoff management and collisions. In this paper, a new channel access mechanism is designed for the buffer constraint sensor devices to reduce the packet drop rate, energy consumption and collisions. In order to avoid collision due to the hidden terminal problem, a new frame structure is designed for the data transmission. A new superframe structure is proposed to mitigate the problems due to WiFi and ZigBee interference. A modified superframe structure with a new retransmission opportunity for failure devices is proposed to reduce the collisions and retransmission delay with high reliability. Performance evaluation and validation of our scheme indicate that the packet drop rate, throughput, reliability, energy consumption and average delay of the nodes can be improved significantly.

Resistence seam welding thin copper foils

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

Hollar, D.L. Jr.

1991-02-01

Use of flat flexible circuits in the electronics industry is expanding. The term flexible circuits'' is defined here as copper foil which has been bonded to an insulating film such as Kapton film. The foil is photo processed to produce individual circuit paths similar to printed circuit boards. Another insulating film is laminated over the conductors to complete the flexible circuit. Flexible circuits, like multiwire cables, are susceptible to electromagnetic radiation (EMR) interference. On multiwire cables the interference problem is mitigated by adding a woven wire braid shielding over the conductors. Shielding on flexible circuits is accomplished by enclosing themore » circuits in a copper foil envelope. However, the copper foil must be electrically sealed around the flexcircuit to be effective. Ultimately, a resistance seam welding process and appropriate equipment were developed which would provide the required electrical seal between two layers of 2-oz (0.0028-inch thick) copper foil on a 1.1-inch wide, 30-inch long, 0.040-inch thick flexible circuit. 4 refs., 19 figs.« less

Towards a Cognitive Radar: Canada's Third-Generation High Frequency Surface Wave Radar (HFSWR) for Surveillance of the 200 Nautical Mile Exclusive Economic Zone.

PubMed

Ponsford, Anthony; McKerracher, Rick; Ding, Zhen; Moo, Peter; Yee, Derek

2017-07-07

Canada's third-generation HFSWR forms the foundation of a maritime domain awareness system that provides enforcement agencies with real-time persistent surveillance out to and beyond the 200 nautical mile exclusive economic zone (EEZ). Cognitive sense-and-adapt technology and dynamic spectrum management ensures robust and resilient operation in the highly congested High Frequency (HF) band. Dynamic spectrum access enables the system to simultaneously operate on two frequencies on a non-interference and non-protected basis, without impacting other spectrum users. Sense-and-adapt technologies ensure that the system instantaneously switches to a new vacant channel on the detection of another user or unwanted jamming signal. Adaptive signal processing techniques mitigate against electrical noise, interference and clutter. Sense-and-adapt techniques applied at the detector and tracker stages maximize the probability of track initiation whilst minimizing the probability of false or otherwise erroneous track data.

Theoretical analysis and modeling of a photonic integrated circuit for frequency 8-tupled and 24-tupled millimeter wave signal generation.

PubMed

Hasan, Mehedi; Guemri, Rabiaa; Maldonado-Basilio, Ramón; Lucarz, Frédéric; de Bougrenet de la Tocnaye, Jean-Louis; Hall, Trevor

2014-12-15

A photonic circuit design for implementing frequency 8-tupling and 24-tupling is proposed. The front- and back-end of the circuit comprises 4×4 MMI couplers enclosing an array of four pairs of phase modulators and 2×2 MMI couplers. The proposed design for frequency multiplication requires no optical or electrical filters, the operation is not limited to carefully adjusted modulation indexes, and the drift originated from static DC bias is mitigated by making use of the intrinsic phase relations of multi-mode interference couplers. A transfer matrix approach is used to represent the main building blocks of the design and hence to describe the operation of the frequency 8-tupling and 24-tupling. The concept is theoretically developed and demonstrated by simulations. Ideal and imperfect power imbalances in the multi-mode interference couplers, as well as ideal and imperfect phases of the electric drives to the phase modulators, are analyzed.

The Effect of Oral Medication on Wound Healing.

PubMed

Levine, Jeffrey M

2017-03-01

The purpose of this learning activity is to provide information about the effects of oral medications on wound healing. This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to:1. Identify oral medications that aid in wound healing.2. Recognize oral medications that interfere with wound healing. Given the accelerated medical discoveries of recent decades, there is a surprising lack of oral medications that directly improve wound healing. Of the oral medications available, most target ancillary aspects of wound care such as pain management, infection mitigation, and nutrition. This article describes oral pharmacologic agents intended to build new tissue and aid in wound healing, as well as an introduction to oral medications that interfere with wound healing. This review will not discuss the pharmacology of pain management or treatment of infection, nor will it address nutritional supplements.

A Reliable Data Transmission Model for IEEE 802.15.4e Enabled Wireless Sensor Network under WiFi Interference

PubMed Central

Sahoo, Prasan Kumar; Pattanaik, Sudhir Ranjan; Wu, Shih-Lin

2017-01-01

The IEEE 802.15.4e standard proposes Medium Access Control (MAC) to support collision-free wireless channel access mechanisms for industrial, commercial and healthcare applications. However, unnecessary wastage of energy and bandwidth consumption occur due to inefficient backoff management and collisions. In this paper, a new channel access mechanism is designed for the buffer constraint sensor devices to reduce the packet drop rate, energy consumption and collisions. In order to avoid collision due to the hidden terminal problem, a new frame structure is designed for the data transmission. A new superframe structure is proposed to mitigate the problems due to WiFi and ZigBee interference. A modified superframe structure with a new retransmission opportunity for failure devices is proposed to reduce the collisions and retransmission delay with high reliability. Performance evaluation and validation of our scheme indicate that the packet drop rate, throughput, reliability, energy consumption and average delay of the nodes can be improved significantly. PMID:28590434