The human respiratory gate

NASA Technical Reports Server (NTRS)

Eckberg, Dwain L.

2003-01-01

Respiratory activity phasically alters membrane potentials of preganglionic vagal and sympathetic motoneurones and continuously modulates their responsiveness to stimulatory inputs. The most obvious manifestation of this 'respiratory gating' is respiratory sinus arrhythmia, the rhythmic fluctuations of electrocardiographic R-R intervals observed in healthy resting humans. Phasic autonomic motoneurone firing, reflecting the throughput of the system, depends importantly on the intensity of stimulatory inputs, such that when levels of stimulation are low (as with high arterial pressure and sympathetic activity, or low arterial pressure and vagal activity), respiratory fluctuations of sympathetic or vagal firing are also low. The respiratory gate has a finite capacity, and high levels of stimulation override the ability of respiration to gate autonomic responsiveness. Autonomic throughput also depends importantly on other factors, including especially, the frequency of breathing, the rate at which the gate opens and closes. Respiratory sinus arrhythmia is small at rapid, and large at slow breathing rates. The strong correlation between systolic pressure and R-R intervals at respiratory frequencies reflects the influence of respiration on these two measures, rather than arterial baroreflex physiology. A wide range of evidence suggests that respiratory activity gates the timing of autonomic motoneurone firing, but does not influence its tonic level. I propose that the most enduring significance of respiratory gating is its use as a precisely controlled experimental tool to tease out and better understand otherwise inaccessible human autonomic neurophysiological mechanisms.

Effect of stochastic gating on channel-facilitated transport of non-interacting and strongly repelling solutes.

PubMed

Berezhkovskii, Alexander M; Bezrukov, Sergey M

2017-08-28

Ligand- or voltage-driven stochastic gating-the structural rearrangements by which the channel switches between its open and closed states-is a fundamental property of biological membrane channels. Gating underlies the channel's ability to respond to different stimuli and, therefore, to be functionally regulated by the changing environment. The accepted understanding of the gating effect on the solute flux through the channel is that the mean flux is the product of the flux through the open channel and the probability of finding the channel in the open state. Here, using a diffusion model of channel-facilitated transport, we show that this is true only when the gating is much slower than the dynamics of solute translocation through the channel. If this condition breaks, the mean flux could differ from this simple estimate by orders of magnitude.

RHrFPGA Radiation-Hardened Re-programmable Field-Programmable Gate Array

NASA Technical Reports Server (NTRS)

Sanders, A. B.; LaBel, K. A.; McCabe, J. F.; Gardner, G. A.; Lintz, J.; Ross, C.; Golke, K.; Burns, B.; Carts, M. A.; Kim, H. S.

2004-01-01

Viewgraphs on the development of the Radiation-Hardened Re-programmable Field-Programmable Gate Array (RHrFPGA) are presented. The topics include: 1) Radiation Test Suite; 2) Testing Interface; 3) Test Configuration; 4) Facilities; 5) Test Programs; 6) Test Procedure; and 7) Test Results. A summary of heavy ion and proton testing is also included.

Non-contact respiration monitoring for in-vivo murine micro computed tomography: characterization and imaging applications

NASA Astrophysics Data System (ADS)

Burk, Laurel M.; Lee, Yueh Z.; Wait, J. Matthew; Lu, Jianping; Zhou, Otto Z.

2012-09-01

A cone beam micro-CT has previously been utilized along with a pressure-tracking respiration sensor to acquire prospectively gated images of both wild-type mice and various adult murine disease models. While the pressure applied to the abdomen of the subject by this sensor is small and is generally without physiological effect, certain disease models of interest, as well as very young animals, are prone to atelectasis with added pressure, or they generate too weak a respiration signal with this method to achieve optimal prospective gating. In this work we present a new fibre-optic displacement sensor which monitors respiratory motion of a subject without requiring physical contact. The sensor outputs an analogue signal which can be used for prospective respiration gating in micro-CT imaging. The device was characterized and compared against a pneumatic air chamber pressure sensor for the imaging of adult wild-type mice. The resulting images were found to be of similar quality with respect to physiological motion blur; the quality of the respiration signal trace obtained using the non-contact sensor was comparable to that of the pressure sensor and was superior for gating purposes due to its better signal-to-noise ratio. The non-contact sensor was then used to acquire in-vivo micro-CT images of a murine model for congenital diaphragmatic hernia and of 11-day-old mouse pups. In both cases, quality CT images were successfully acquired using this new respiration sensor. Despite the presence of beam hardening artefacts arising from the presence of a fibre-optic cable in the imaging field, we believe this new technique for respiration monitoring and gating presents an opportunity for in-vivo imaging of disease models which were previously considered too delicate for established animal handling methods.

Study of proton radiation effects among diamond and rectangular gate MOSFET layouts

NASA Astrophysics Data System (ADS)

Seixas, L. E., Jr.; Finco, S.; Silveira, M. A. G.; Medina, N. H.; Gimenez, S. P.

2017-01-01

This paper describes an experimental comparative study of proton ionizing radiation effects between the metal-oxide-semiconductor (MOS) Field Effect Transistors (MOSFETs) implemented with hexagonal gate shapes (diamond) and their respective counterparts designed with the classical rectangular ones, regarding the same gate areas, channel widths and geometrical ratios (W/L). The devices were manufactured by using the 350 nm bulk complementary MOS (CMOS) integrated circuits technology. The diamond MOSFET with α angles higher or equal to 90° tends to present a smaller vulnerability to the high doses ionizing radiation than those observed in the typical rectangular MOSFET counterparts.

Radiation hardening of MOS devices by boron. [for stabilizing gate threshold potential of field effect device

NASA Technical Reports Server (NTRS)

Danchenko, V. (Inventor)

1974-01-01

A technique is described for radiation hardening of MOS devices and specifically for stabilizing the gate threshold potential at room temperature of a radiation subjected MOS field-effect device with a semiconductor substrate, an insulating layer of oxide on the substrate, and a gate electrode disposed on the insulating layer. The boron is introduced within a layer of the oxide of about 100 A-300 A thickness immediately adjacent the semiconductor-insulator interface. The concentration of boron in the oxide layer is preferably maintained on the order of 10 to the 18th power atoms/cu cm. The technique serves to reduce and substantially annihilate radiation induced positive gate charge accumulations.

Effect of stochastic gating on channel-facilitated transport of non-interacting and strongly repelling solutes

NASA Astrophysics Data System (ADS)

Berezhkovskii, Alexander M.; Bezrukov, Sergey M.

2017-08-01

Ligand- or voltage-driven stochastic gating—the structural rearrangements by which the channel switches between its open and closed states—is a fundamental property of biological membrane channels. Gating underlies the channel's ability to respond to different stimuli and, therefore, to be functionally regulated by the changing environment. The accepted understanding of the gating effect on the solute flux through the channel is that the mean flux is the product of the flux through the open channel and the probability of finding the channel in the open state. Here, using a diffusion model of channel-facilitated transport, we show that this is true only when the gating is much slower than the dynamics of solute translocation through the channel. If this condition breaks, the mean flux could differ from this simple estimate by orders of magnitude.

Determination of prospective displacement-based gate threshold for respiratory-gated radiation delivery from retrospective phase-based gate threshold selected at 4D CT simulation.

PubMed

Vedam, S; Archambault, L; Starkschall, G; Mohan, R; Beddar, S

2007-11-01

and delivery gate thresholds to within 0.3%. For patient data analysis, differences between simulation and delivery gate thresholds are reported as a fraction of the total respiratory motion range. For the smaller phase interval, the differences between simulation and delivery gate thresholds are 8 +/- 11% and 14 +/- 21% with and without audio-visual biofeedback, respectively, when the simulation gate threshold is determined based on the mean respiratory displacement within the 40%-60% gating phase interval. For the longer phase interval, corresponding differences are 4 +/- 7% and 8 +/- 15% with and without audiovisual biofeedback, respectively. Alternatively, when the simulation gate threshold is determined based on the maximum average respiratory displacement within the gating phase interval, greater differences between simulation and delivery gate thresholds are observed. A relationship between retrospective simulation gate threshold and prospective delivery gate threshold for respiratory gating is established and validated for regular and nonregular respiratory motion. Using this relationship, the delivery gate threshold can be reliably estimated at the time of 4D CT simulation, thereby improving the accuracy and efficiency of respiratory-gated radiation delivery.

Reduction of the estimated radiation dose and associated patient risk with prospective ECG-gated 256-slice CT coronary angiography

NASA Astrophysics Data System (ADS)

Efstathopoulos, E. P.; Kelekis, N. L.; Pantos, I.; Brountzos, E.; Argentos, S.; Grebáč, J.; Ziaka, D.; Katritsis, D. G.; Seimenis, I.

2009-09-01

Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have been reported. Prospective ECG-gating using a 'step-and-shoot' axial scanning protocol has been shown to reduce radiation exposure effectively while maintaining diagnostic accuracy. 256-slice scanners with 80 mm detector coverage have been currently introduced into practice, but their impact on radiation exposure has not been adequately studied. The aim of this study was to assess radiation doses associated with CT coronary angiography using a 256-slice CT scanner. Radiation doses were estimated for 25 patients scanned with either prospective or retrospective ECG-gating. Image quality was assessed objectively in terms of mean CT attenuation at selected regions of interest on axial coronary images and subjectively by coronary segment quality scoring. It was found that radiation doses associated with prospective ECG-gating were significantly lower than retrospective ECG-gating (3.2 ± 0.6 mSv versus 13.4 ± 2.7 mSv). Consequently, the radiogenic fatal cancer risk for the patient is much lower with prospective gating (0.0176% versus 0.0737%). No statistically significant differences in image quality were observed between the two scanning protocols for both objective and subjective quality assessments. Therefore, prospective ECG-gating using a 'step-and-shoot' protocol that covers the cardiac anatomy in two axial acquisitions effectively reduces radiation doses in 256-slice CT coronary angiography without compromising image quality.

Determination of prospective displacement-based gate threshold for respiratory-gated radiation delivery from retrospective phase-based gate threshold selected at 4D CT simulation

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

Vedam, S.; Archambault, L.; Starkschall, G.

2007-11-15

simulation and delivery gate thresholds to within 0.3%. For patient data analysis, differences between simulation and delivery gate thresholds are reported as a fraction of the total respiratory motion range. For the smaller phase interval, the differences between simulation and delivery gate thresholds are 8{+-}11% and 14{+-}21% with and without audio-visual biofeedback, respectively, when the simulation gate threshold is determined based on the mean respiratory displacement within the 40%-60% gating phase interval. For the longer phase interval, corresponding differences are 4{+-}7% and 8{+-}15% with and without audio-visual biofeedback, respectively. Alternatively, when the simulation gate threshold is determined based on the maximum average respiratory displacement within the gating phase interval, greater differences between simulation and delivery gate thresholds are observed. A relationship between retrospective simulation gate threshold and prospective delivery gate threshold for respiratory gating is established and validated for regular and nonregular respiratory motion. Using this relationship, the delivery gate threshold can be reliably estimated at the time of 4D CT simulation, thereby improving the accuracy and efficiency of respiratory-gated radiation delivery.« less

p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy

PubMed Central

Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

2015-01-01

Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6, heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy. PMID:26177264

p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy.

PubMed

Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

2015-09-01

Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6 , heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Short-Term Facilitation at a Detonator Synapse Requires the Distinct Contribution of Multiple Types of Voltage-Gated Calcium Channels.

PubMed

Chamberland, Simon; Evstratova, Alesya; Tóth, Katalin

2017-05-10

Neuronal calcium elevations are shaped by several key parameters, including the properties, density, and the spatial location of voltage-gated calcium channels (VGCCs). These features allow presynaptic terminals to translate complex firing frequencies and tune the amount of neurotransmitter released. Although synchronous neurotransmitter release relies on both P/Q- and N-type VGCCs at hippocampal mossy fiber-CA3 synapses, the specific contribution of VGCCs to calcium dynamics, neurotransmitter release, and short-term facilitation remains unknown. Here, we used random-access two-photon calcium imaging together with electrophysiology in acute mouse hippocampal slices to dissect the roles of P/Q- and N-type VGCCs. Our results show that N-type VGCCs control glutamate release at a limited number of release sites through highly localized Ca 2+ elevations and support short-term facilitation by enhancing multivesicular release. In contrast, Ca 2+ entry via P/Q-type VGCCs promotes the recruitment of additional release sites through spatially homogeneous Ca 2+ elevations. Altogether, our results highlight the specialized contribution of P/Q- and N-types VGCCs to neurotransmitter release. SIGNIFICANCE STATEMENT In presynaptic terminals, neurotransmitter release is dynamically regulated by the transient opening of different types of voltage-gated calcium channels. Hippocampal giant mossy fiber terminals display extensive short-term facilitation during repetitive activity, with a large several fold postsynaptic response increase. Though, how giant mossy fiber terminals leverage distinct types of voltage-gated calcium channels to mediate short-term facilitation remains unexplored. Here, we find that P/Q- and N-type VGCCs generate different spatial patterns of calcium elevations in giant mossy fiber terminals and support short-term facilitation through specific participation in two mechanisms. Whereas N-type VGCCs contribute only to the synchronization of multivesicular release

Usefulness of a new online patient-specific quality assurance system for respiratory-gated radiotherapy.

PubMed

Kurosawa, Tomoyuki; Tachibana, Hidenobu; Moriya, Shunsuke; Miyakawa, Shin; Nishio, Teiji; Sato, Masanori

2017-11-01

The accuracy of gated irradiation may decrease when treatment is performed with short "beam-on" times. Also, the dose is subject to variation between treatment sessions if the respiratory rate is irregular. We therefore evaluated the impact of the differences between gated and non-gated treatment on doses using a new online quality assurance (QA) system for respiratory-gated radiotherapy. We generated dose estimation models to associate dose and pulse information using a 0.6 cc Farmer chamber and our QA system. During gated irradiation with each of seven regular and irregular respiratory patterns, with the Farmer chamber readings as references, we evaluated our QA system's accuracy. We then used the QA system to assess the impact of respiratory patterns on dose distribution for three lung and three liver radiotherapy plans. Gated and non-gated plans were generated and compared. There was agreement within 1.7% between the ionization chamber and our system for several regular and irregular motion patterns. For dose distributions with measured errors, there were larger differences between gated and non-gated treatment for high-dose regions within the planned treatment volume (PTV). Compared with a non-gated plan, PTV D 95% for a gated plan decreased by -1.5% to -2.6%. Doses to organs at risk were similar with both plans. Our simple system estimated the radiation dose to the patient using only pulse information from the linac, even during irregular respiration. The quality of gated irradiation for each patient can be verified fraction by fraction. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Management of the baseline shift using a new and simple method for respiratory-gated radiation therapy: Detectability and effectiveness of a flexible monitoring system

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

Tachibana, Hidenobu; Kitamura, Nozomi; Ito, Yasushi

2011-07-15

the sternum. The baseline shift-monitoring system with the displacement-based methods for highly accurate respiratory-gated treatments should be used to make most of the displacement-based gating methods. Conclusions: The advent of intensity modulated radiation therapy and volumetric modulated radiation therapy facilitates margin reduction for the planning target volumes and the OARs, but highly accurate irradiation is needed to achieve target coverage and OAR sparing with a small margin. The baseline shifts can affect treatment not only with the respiratory gating system but also without the system. Our system can manage the baseline shift and also enables treatment irradiation to be undertaken with high accuracy.« less

Retrospective respiration-gated whole-body photoacoustic computed tomography of mice

NASA Astrophysics Data System (ADS)

Xia, Jun; Chen, Wanyi; Maslov, Konstantin; Anastasio, Mark A.; Wang, Lihong V.

2014-01-01

Photoacoustic tomography (PAT) is an emerging technique that has a great potential for preclinical whole-body imaging. To date, most whole-body PAT systems require multiple laser shots to generate one cross-sectional image, yielding a frame rate of <1 Hz. Because a mouse breathes at up to 3 Hz, without proper gating mechanisms, acquired images are susceptible to motion artifacts. Here, we introduce, for the first time to our knowledge, retrospective respiratory gating for whole-body photoacoustic computed tomography. This new method involves simultaneous capturing of the animal's respiratory waveform during photoacoustic data acquisition. The recorded photoacoustic signals are sorted and clustered according to the respiratory phase, and an image of the animal at each respiratory phase is reconstructed subsequently from the corresponding cluster. The new method was tested in a ring-shaped confocal photoacoustic computed tomography system with a hardware-limited frame rate of 0.625 Hz. After respiratory gating, we observed sharper vascular and anatomical images at different positions of the animal body. The entire breathing cycle can also be visualized at 20 frames/cycle.

Floating Gate sensor for in-vivo dosimetry in radiation therapies. Design and first characterization.

NASA Astrophysics Data System (ADS)

Faigon, A.; Martinez Vazquez, I.; Carbonetto, S.; García Inza, M.; G

2017-01-01

A floating gate dosimeter was designed and fabricated in a standard CMOS technology. The design guides and characterization are presented. The characterization included the controlled charging by tunneling of the floating gate, and its discharging under irradiation while measuring the transistor drain current whose change is the measure of the absorbed dose. The resolution of the obtained device is close to 1 cGy satisfying the requirements for most radiation therapies dosimetry. Pending statistical proofs, the dosimeter is a potential candidate for wide in-vivo control of radiotherapy treatments.

CMOS gate array characterization procedures

NASA Astrophysics Data System (ADS)

Spratt, James P.

1993-09-01

Present procedures are inadequate for characterizing the radiation hardness of gate array product lines prior to personalization because the selection of circuits to be used, from among all those available in the manufacturer's circuit library, is usually uncontrolled. (Some circuits are fundamentally more radiation resistant than others.) In such cases, differences in hardness can result between different designs of the same logic function. Hardness also varies because many gate arrays feature large custom-designed megacells (e.g., microprocessors and random access memories-MicroP's and RAM's). As a result, different product lines cannot be compared equally. A characterization strategy is needed, along with standardized test vehicle(s), methodology, and conditions, so that users can make informed judgments on which gate arrays are best suited for their needs. The program described developed preferred procedures for the radiation characterization of gate arrays, including a gate array evaluation test vehicle, featuring a canary circuit, designed to define the speed versus hardness envelope of the gate array. A multiplier was chosen for this role, and a baseline multiplier architecture is suggested that could be incorporated into an existing standard evaluation circuit chip.

Respiratory gating based on internal electromagnetic motion monitoring during stereotactic liver radiation therapy: First results.

PubMed

Poulsen, Per Rugaard; Worm, Esben Schjødt; Hansen, Rune; Larsen, Lars Peter; Grau, Cai; Høyer, Morten

2015-01-01

Intrafraction motion may compromise the target dose in stereotactic body radiation therapy (SBRT) of tumors in the liver. Respiratory gating can improve the treatment delivery, but gating based on an external surrogate signal may be inaccurate. This is the first paper reporting on respiratory gating based on internal electromagnetic monitoring during liver SBRT. Two patients with solitary liver metastases were treated with respiratory-gated SBRT guided by three implanted electromagnetic transponders. The treatment was delivered in end-exhale with beam-on when the centroid of the three transponders deviated less than 3 mm [left-right (LR) and anterior-posterior (AP) directions] and 4mm [cranio-caudal (CC)] from the planned position. For each treatment fraction, log files were used to determine the transponder motion during beam-on in the actual gated treatments and in simulated treatments without gating. The motion was used to reconstruct the dose to the clinical target volume (CTV) with and without gating. The reduction in D95 (minimum dose to 95% of the CTV) relative to the plan was calculated for both treatment courses. With gating the maximum course mean (standard deviation) geometrical error in any direction was 1.2 mm (1.8 mm). Without gating the course mean error would mainly increase for Patient 1 [to -2.8 mm (1.6 mm) (LR), 7.1 mm (5.8 mm) (CC), -2.6 mm (2.8mm) (AP)] due to a large systematic cranial baseline drift at each fraction. The errors without gating increased only slightly for Patient 2. The reduction in CTV D95 was 0.5% (gating) and 12.1% (non-gating) for Patient 1 and 0.3% (gating) and 1.7% (non-gating) for Patient 2. The mean duty cycle was 55%. Respiratory gating based on internal electromagnetic motion monitoring was performed for two liver SBRT patients. The gating added robustness to the dose delivery and ensured a high CTV dose even in the presence of large intrafraction motion.

Trapped-Ion Quantum Logic with Global Radiation Fields.

PubMed

Weidt, S; Randall, J; Webster, S C; Lake, K; Webb, A E; Cohen, I; Navickas, T; Lekitsch, B; Retzker, A; Hensinger, W K

2016-11-25

Trapped ions are a promising tool for building a large-scale quantum computer. However, the number of required radiation fields for the realization of quantum gates in any proposed ion-based architecture scales with the number of ions within the quantum computer, posing a major obstacle when imagining a device with millions of ions. Here, we present a fundamentally different approach for trapped-ion quantum computing where this detrimental scaling vanishes. The method is based on individually controlled voltages applied to each logic gate location to facilitate the actual gate operation analogous to a traditional transistor architecture within a classical computer processor. To demonstrate the key principle of this approach we implement a versatile quantum gate method based on long-wavelength radiation and use this method to generate a maximally entangled state of two quantum engineered clock qubits with fidelity 0.985(12). This quantum gate also constitutes a simple-to-implement tool for quantum metrology, sensing, and simulation.

Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapy

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

Cai Jing; McLawhorn, Robert; Read, Paul W.

Purpose: To investigate the effects of breathing variation on gating window internal target volume (ITV{sub GW}) in respiratory gated radiation therapy. Method and Materials: Two-dimensional dynamic MRI (dMRI) of lung motion was acquired in ten volunteers and eight lung cancer patients. Resorted dMRI using 4DCT acquisition method (RedCAM) was generated for selected subjects by simulating the image rebinning process. A dynamic software generated phantom (dSGP) was created by moving a solid circle (to mimic the ''tumor'') with dMRI-determined motion trajectories. The gating window internal target area (ITA{sub GW}, 2D counterpart of ITV{sub GW}) was determined from both RedCAM and dSGP/dMRI.more » Its area (A), major axis (L1), minor axis (L2), and similarity (S) were calculated and compared. Results: In the phantom study of 3 cm tumor, measurements of the ITA{sub GW} from dSGP (A=10.0{+-}1.3 cm{sup 2}, L1=3.8{+-}0.4 cm, and L2=3.3{+-}0.1 cm) are significantly (p<0.001) greater than those from RedCAM (A=8.5{+-}0.7 cm{sup 2}, L1=3.5{+-}0.2 cm, and L2=3.1{+-}0.1 cm). Similarly, the differences are significantly greater (p<0.001) for the 1 cm tumor (A=1.9{+-}0.5 cm{sup 2}, L1=1.9{+-}0.4 cm, and L2=1.3{+-}0.1 cm in dSGP; A=1.3{+-}0.1 cm{sup 2}, L1=1.5{+-}0.2 cm, and L2=1.1{+-}0.1 cm in RedCAM). In patient studies, measurements of the ITA{sub GW} from dMRI (A=15.5{+-}8.2 cm{sup 2}, L1=5.0{+-}1.1 cm, and L2=3.8{+-}1.2 cm) are also significantly greater (p<0.05) than those from RedCAM (A=13.2{+-}8.5 cm{sup 2}, L1=4.3{+-}1.4 cm, and L2=3.7{+-}1.2 cm). Similarities were 0.9{+-}0.1, 0.8{+-}0.1, and 0.8{+-}0.1 in the 3 cm tumor phantom, 1 cm tumor phantom, and patient studies, respectively. Conclusion: ITV{sub GW} can be underestimated by 4DCT due to breathing variations. An additional margin may be needed to account for this potential error in generating a PTV{sub GW}. Cautions need to be taken when generating ITV{sub GW} from 4DCT in respiratory gated radiation therapy

SU-E-J-169: The Dosimetric and Temporal Effects of Respiratory-Gated Radiation Therapy in Lung Cancer Patients

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

Rouabhi, O; Gross, B; Xia, J

2015-06-15

Purpose: To evaluate the dosimetric and temporal effects of high dose rate treatment mode for respiratory-gated radiation therapy in lung cancer patients. Methods: Treatment plans from five lung cancer patients (3 nongated (Group 1), 2 gated at 80EX-80IN (Group 2)) were retrospectively evaluated. The maximum tumor motions range from 6–12 mm. Using the same planning criteria, four new treatment plans, corresponding to four gating windows (20EX–20IN, 40EX–40IN, 60EX–60IN, and 80EX–80IN), were generated for each patient. Mean tumor dose (MTD), mean lung dose (MLD), and lung V20 were used to assess the dosimetric effects. A MATLAB algorithm was developed to computemore » treatment time by considering gantry rotation time, time to position collimator leaves, dose delivery time (scaled relative to the gating window), and communication overhead. Treatment delivery time for each plan was estimated using a 500 MU/min dose rate for the original plans and a 1500 MU/min dose rate for the gated plans. Results: Differences in MTD were less than 1Gy across plans for all five patients. MLD and lung V20 were on average reduced between −16.1% to −6.0% and −20.0% to −7.2%, respectively for non-gated plans when compared with the corresponding gated plans, and between − 5.8% to −4.2% and −7.0% to −5.4%, respectively for plans originally gated at 80EX–80IN when compared with the corresponding 20EX-20IN to 60EX– 60IN gated plans. Treatment delivery times of gated plans using high dose rate were reduced on average between −19.7% (−1.9min) to −27.2% (−2.7min) for originally non-gated plans and −15.6% (−0.9min) to −20.3% (−1.2min) for originally 80EX-80IN gated plans. Conclusion: Respiratory-gated radiation therapy in lung cancer patients can reduce lung toxicity, while maintaining tumor dose. Using a gated high-dose-rate treatment, delivery time comparable to non-gated normal-dose-rate treatment can be achieved. This research is supported by

Organ motion due to respiration: the state of the art and applications in interventional radiology and radiation oncology

NASA Astrophysics Data System (ADS)

Cleary, Kevin R.; Mulcahy, Maureen; Piyasena, Rohan; Zhou, Tong; Dieterich, Sonja; Xu, Sheng; Banovac, Filip; Wong, Kenneth H.

2005-04-01

Tracking organ motion due to respiration is important for precision treatments in interventional radiology and radiation oncology, among other areas. In interventional radiology, the ability to track and compensate for organ motion could lead to more precise biopsies for applications such as lung cancer screening. In radiation oncology, image-guided treatment of tumors is becoming technically possible, and the management of organ motion then becomes a major issue. This paper will review the state-of-the-art in respiratory motion and present two related clinical applications. Respiratory motion is an important topic for future work in image-guided surgery and medical robotics. Issues include how organs move due to respiration, how much they move, how the motion can be compensated for, and what clinical applications can benefit from respiratory motion compensation. Technology that can be applied for this purpose is now becoming available, and as that technology evolves, the subject will become an increasingly interesting and clinically valuable topic of research.

Respirators, internal dose, and Oyster Creek

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

Michal, R.

1996-06-01

This article looks at the experience of Oyster Creek in relaxing the requirements for the use of respirators in all facets of plant maintenance, on the overall dose received by plant maintenance personnel. For Roger Shaw, director of radiological controls for three years at GPU Nuclear Corporation`s Oyster Creek nuclear plant the correct dose balance is determined on a job-by-job basis: Does the job require a respirator, which is an effective means of decreasing worker inhalation of airborne radioactive particles? Will wearing a respirator slow down a worker, consequently increasing whole body radiation exposure by prolonging the time spent inmore » fields of high external radiation? How does respiratory protection affect worker safety and to what degree? While changes to the Nuclear Regulatory Commission`s 10CFR20 have updated the radiation protection requirements for the nuclear industry, certain of the revisions have been directed specifically at reducing worker dose, Shaw said. {open_quotes}It basically delineates that dose is dose,{close_quotes} Shaw said, {open_quotes}regardless of whether it is acquired externally or internally.{close_quotes} The revision of Part 20 changed the industry`s attitude toward internal dose, which had always been viewed negatively. {open_quotes}Internal dose was always seen as preventable by wearing respirators and by using engineering techniques such as ventilation control and decontamination,{close_quotes} Shaw said, {open_quotes}whereas external dose, although reduced where practical, was seen as a fact of the job.{close_quotes}« less

A gated deep inspiration breath‐hold radiation therapy technique using a linear position transducer

PubMed Central

Denissova, Svetlana I.; Yewondwossen, Mammo H.; Andrew, John W.; Hale, Michael E.; Murphy, Carl H.; Purcell, Scott R.

2005-01-01

For patients with thoracic and abdominal lesions, respiration‐induced internal organ motion and deformations during radiation therapy are limiting factors for the administration of high radiation dose. To increase the dose to the tumor and to reduce margins, tumor movement during treatment must be minimized. Currently, several types of breath‐synchronized systems are in use. These systems include respiratory gating, deep inspiration breath‐hold, active breathing control, and voluntary breath‐hold. We used a linear position transducer (LPT) to monitor changes in a patient's abdominal cross‐sectional area. The LPT tracks changes in body circumference during the respiratory cycle using a strap connected to the LPT and wrapped around the patient's torso. The LPT signal is monitored by a computer that provides a real‐time plot of the patient's breathing pattern. In our technique, we use a CT study with multiple gated acquisitions. The Philips Medical Systems Q series CT imaging system is capable of operating in conjunction with a contrast injector. This allows a patient performing the deep inspiration breath‐hold maneuver to send a signal to trigger the CT scanner acquisitions. The LPT system, when interfaced to a LINAC, allows treatment to be delivered only during deep inspiration breath‐hold periods. Treatment stops automatically if the lung volume drops from a preset value. The whole treatment can be accomplished with 1 to 3 breath‐holds. This technique has been used successfully to combine automatically gated radiation delivery with the deep inspiration breath‐hold technique. This improves the accuracy of treatment for moving tumors, providing better target coverage, sparing more healthy tissue, and saving machine time. PACS numbers: 87.53.2j, 87.57.‐s PMID:15770197

SU-E-J-211: Design and Study of In-House Software Based Respiratory Motion Monitoring, Controlling and Breath-Hold Device for Gated Radiotherapy

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

Shanmugam, Senthilkumar

Purpose: The purpose of this present work was to fabricate an in-house software based respiratory monitoring, controlling and breath-hold device using computer software programme which guides the patient to have uniform breath hold in response to request during the gated radiotherapy. Methods: The respiratory controlling device consists of a computer, inhouse software, video goggles, a highly sensitive sensor for measurement of distance, mounting systems, a camera, a respiratory signal device, a speaker and a visual indicator. The computer is used to display the respiratory movements of the patient with digital as well as analogue respiration indicators during the respiration cycle,more » to control, breath-hold and analyze the respiratory movement using indigenously developed software. Results: Studies were conducted with anthropomophic phantoms by simulating the respiratory motion on phantoms and recording the respective movements using the respiratory monitoring device. The results show good agreement between the simulated and measured movements. Further studies were conducted for 60 cancer patients with several types of cancers in the thoracic region. The respiratory movement cycles for each fraction of radiotherapy treatment were recorded and compared. Alarm indications are provided in the system to indicate when the patient breathing movement exceeds the threshold level. This will help the patient to maintain uniform breath hold during the radiotherapy treatment. Our preliminary clinical test results indicate that our device is highly reliable and able to maintain the uniform respiratory motion and breathe hold during the entire course of gated radiotherapy treatment. Conclusion: An indigenous respiratory monitoring device to guide the patient to have uniform breath hold device was fabricated. The alarm feature and the visual waveform indicator in the system guide the patient to have normal respiration. The signal from the device can be connected to the

Gated strip proportional detector

DOEpatents

Morris, C.L.; Idzorek, G.C.; Atencio, L.G.

1985-02-19

A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10/sup 6/. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Gated strip proportional detector

DOEpatents

Morris, Christopher L.; Idzorek, George C.; Atencio, Leroy G.

1987-01-01

A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10.sup.6. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Effect of respiratory gating on reducing lung motion artifacts in PET imaging of lung cancer.

PubMed

Nehmeh, S A; Erdi, Y E; Ling, C C; Rosenzweig, K E; Squire, O D; Braban, L E; Ford, E; Sidhu, K; Mageras, G S; Larson, S M; Humm, J L

2002-03-01

Positron emission tomography (PET) has shown an increase in both sensitivity and specificity over computed tomography (CT) in lung cancer. However, motion artifacts in the 18F fluorodioxydoglucose (FDG) PET images caused by respiration persists to be an important factor in degrading PET image quality and quantification. Motion artifacts lead to two major effects: First, it affects the accuracy of quantitation, producing a reduction of the measured standard uptake value (SUV). Second, the apparent lesion volume is overestimated. Both impact upon the usage of PET images for radiation treatment planning. The first affects the visibility, or contrast, of the lesion. The second results in an increase in the planning target volume, and consequently a greater radiation dose to the normal tissues. One way to compensate for this effect is by applying a multiple-frame capture technique. The PET data are then acquired in synchronization with the respiratory motion. Reduction in smearing due to gating was investigated in both phantoms and patient studies. Phantom studies showed a dependence of the reduction in smearing on the lesion size, the motion amplitude, and the number of bins used for data acquisition. These studies also showed an improvement in the target-to-background ratio, and a more accurate measurement of the SUV. When applied to one patient, respiratory gating showed a 28% reduction in the total lesion volume, and a 56.5% increase in the SUV. This study was conducted as a proof of principle that a gating technique can effectively reduce motion artifacts in PET image acquisition.

Automatic respiration tracking for radiotherapy using optical 3D camera

NASA Astrophysics Data System (ADS)

Li, Tuotuo; Geng, Jason; Li, Shidong

2013-03-01

Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The accurate 3D surface images offer crucial information in image-guided radiation therapy (IGRT) treatments for accurate patient repositioning and respiration management. However, applications of O3D imaging techniques to image-guided radiotherapy have been clinically challenged by body deformation, pathological and anatomical variations among individual patients, extremely high dimensionality of the 3D surface data, and irregular respiration motion. In existing clinical radiation therapy (RT) procedures target displacements are caused by (1) inter-fractional anatomy changes due to weight, swell, food/water intake; (2) intra-fractional variations from anatomy changes within any treatment session due to voluntary/involuntary physiologic processes (e.g. respiration, muscle relaxation); (3) patient setup misalignment in daily reposition due to user errors; and (4) changes of marker or positioning device, etc. Presently, viable solution is lacking for in-vivo tracking of target motion and anatomy changes during the beam-on time without exposing patient with additional ionized radiation or high magnet field. Current O3D-guided radiotherapy systems relay on selected points or areas in the 3D surface to track surface motion. The configuration of the marks or areas may change with time that makes it inconsistent in quantifying and interpreting the respiration patterns. To meet the challenge of performing real-time respiration tracking using O3D imaging technology in IGRT, we propose a new approach to automatic respiration motion analysis based on linear dimensionality reduction technique based on PCA (principle component analysis). Optical 3D image sequence is decomposed with principle component analysis into a limited number of independent (orthogonal) motion patterns (a low dimension eigen-space span by eigen-vectors). New

Gating the glutamate gate of CLC-2 chloride channel by pore occupancy

PubMed Central

De Jesús-Pérez, José J.; Castro-Chong, Alejandra; Shieh, Ru-Chi; Hernández-Carballo, Carmen Y.; De Santiago-Castillo, José A.

2016-01-01

CLC-2 channels are dimeric double-barreled chloride channels that open in response to hyperpolarization. Hyperpolarization activates protopore gates that independently regulate the permeability of the pore in each subunit and the common gate that affects the permeability through both pores. CLC-2 channels lack classic transmembrane voltage–sensing domains; instead, their protopore gates (residing within the pore and each formed by the side chain of a glutamate residue) open under repulsion by permeant intracellular anions or protonation by extracellular H+. Here, we show that voltage-dependent gating of CLC-2: (a) is facilitated when permeant anions (Cl−, Br−, SCN−, and I−) are present in the cytosolic side; (b) happens with poorly permeant anions fluoride, glutamate, gluconate, and methanesulfonate present in the cytosolic side; (c) depends on pore occupancy by permeant and poorly permeant anions; (d) is strongly facilitated by multi-ion occupancy; (e) is absent under likely protonation conditions (pHe = 5.5 or 6.5) in cells dialyzed with acetate (an impermeant anion); and (f) was the same at intracellular pH 7.3 and 4.2; and (g) is observed in both whole-cell and inside-out patches exposed to increasing [Cl−]i under unlikely protonation conditions (pHe = 10). Thus, based on our results we propose that hyperpolarization activates CLC-2 mainly by driving intracellular anions into the channel pores, and that protonation by extracellular H+ plays a minor role in dislodging the glutamate gate. PMID:26666914

Estimation of internal organ motion-induced variance in radiation dose in non-gated radiotherapy

NASA Astrophysics Data System (ADS)

Zhou, Sumin; Zhu, Xiaofeng; Zhang, Mutian; Zheng, Dandan; Lei, Yu; Li, Sicong; Bennion, Nathan; Verma, Vivek; Zhen, Weining; Enke, Charles

2016-12-01

In the delivery of non-gated radiotherapy (RT), owing to intra-fraction organ motion, a certain degree of RT dose uncertainty is present. Herein, we propose a novel mathematical algorithm to estimate the mean and variance of RT dose that is delivered without gating. These parameters are specific to individual internal organ motion, dependent on individual treatment plans, and relevant to the RT delivery process. This algorithm uses images from a patient’s 4D simulation study to model the actual patient internal organ motion during RT delivery. All necessary dose rate calculations are performed in fixed patient internal organ motion states. The analytical and deterministic formulae of mean and variance in dose from non-gated RT were derived directly via statistical averaging of the calculated dose rate over possible random internal organ motion initial phases, and did not require constructing relevant histograms. All results are expressed in dose rate Fourier transform coefficients for computational efficiency. Exact solutions are provided to simplified, yet still clinically relevant, cases. Results from a volumetric-modulated arc therapy (VMAT) patient case are also presented. The results obtained from our mathematical algorithm can aid clinical decisions by providing information regarding both mean and variance of radiation dose to non-gated patients prior to RT delivery.

Diffusive flux in a model of stochastically gated oxygen transport in insect respiration

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

Berezhkovskii, Alexander M.; Shvartsman, Stanislav Y.

Oxygen delivery to insect tissues is controlled by transport through a branched tubular network that is connected to the atmosphere by valve-like gates, known as spiracles. In certain physiological regimes, the spiracles appear to be randomly switching between open and closed states. Quantitative analysis of this regime leads a reaction-diffusion problem with stochastically switching boundary condition. We derive an expression for the diffusive flux at long times in this problem. Our approach starts with the derivation of the passage probability for a single particle that diffuses between a stochastically gated boundary, which models the opening and closing spiracle, and themore » perfectly absorbing boundary, which models oxygen absorption by the tissue. This passage probability is then used to derive an expression giving the diffusive flux as a function of the geometric parameters of the tube and characteristic time scales of diffusion and gate dynamics.« less

Diffusive flux in a model of stochastically gated oxygen transport in insect respiration.

PubMed

Berezhkovskii, Alexander M; Shvartsman, Stanislav Y

2016-05-28

Oxygen delivery to insect tissues is controlled by transport through a branched tubular network that is connected to the atmosphere by valve-like gates, known as spiracles. In certain physiological regimes, the spiracles appear to be randomly switching between open and closed states. Quantitative analysis of this regime leads a reaction-diffusion problem with stochastically switching boundary condition. We derive an expression for the diffusive flux at long times in this problem. Our approach starts with the derivation of the passage probability for a single particle that diffuses between a stochastically gated boundary, which models the opening and closing spiracle, and the perfectly absorbing boundary, which models oxygen absorption by the tissue. This passage probability is then used to derive an expression giving the diffusive flux as a function of the geometric parameters of the tube and characteristic time scales of diffusion and gate dynamics.

A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

NASA Technical Reports Server (NTRS)

Edmonds, L. D.

2016-01-01

Since advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

NASA Technical Reports Server (NTRS)

Edmonds, L. D.

2016-01-01

Because advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

A Prospective Cohort Study of Gated Stereotactic Liver Radiation Therapy Using Continuous Internal Electromagnetic Motion Monitoring.

PubMed

Worm, Esben S; Høyer, Morten; Hansen, Rune; Larsen, Lars P; Weber, Britta; Grau, Cai; Poulsen, Per R

2018-06-01

Intrafraction motion can compromise the treatment accuracy in liver stereotactic body radiation therapy (SBRT). Respiratory gating can improve treatment delivery; however, gating based on external motion surrogates is inaccurate. The present study reports the use of Calypso-based internal electromagnetic motion monitoring for gated liver SBRT. Fifteen patients were included in a study of 3-fraction respiratory gated liver SBRT guided by 3 implanted electromagnetic transponders. The planning target volume was created by a 5-mm axial and 7-mm (n = 12) or 10-mm (n = 3) craniocaudal expansion of the clinical target volume (CTV) and covered with 67% of the prescribed CTV mean dose. Treatment was gated to the end-exhale phase of the respiratory cycle with beam-on when the target deviated <3 mm (left-right/anteroposterior) and 4 mm (craniocaudal) from the planned position, according to the monitored (25-Hz) transponder centroid position. The couch was adjusted remotely if baseline drifts >1 to 2 mm occurred. Log files of transponder motion were used to determine the geometric error and reconstruct the delivered CTV dose in the actual gated treatments and in simulated nongated treatments. No severe side effects were observed in relation to transponder implantation. All 45 treatment fractions were successfully guided using the Calypso system. The mean number of couch corrections during each gated fraction was 2.8 (range 0-7). The mean duty cycle during gated treatment was 62.5% (range 29.1%-84.9%). Without gating, the mean 3-dimensional geometric error during a fraction would have been 5.4 mm (range 2.7-12.1). Gating reduced this error to 2.0 mm (range 1.2-3.0). The patient mean reduction in minimum dose to 95% of the CTV relative to the planned dose was 6.0 percentage points (range 0.7-22.0) without gating and 0.8 percentage point (range 0.2-2.0) with gating. Gating using internal motion monitoring was successfully applied for liver SBRT. It markedly improved the

Evaluation of the MEMS based portable respiratory training system with a tactile sensor for respiratory-gated radiotherapy

NASA Astrophysics Data System (ADS)

Moon, Sun Young; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

2017-10-01

In respiratory-gated radiotherapy, it is important to maintain the regular respiratory cycles of patients. If patients undergo respiration training, their regular breathing pattern is affected. Therefore, we developed a respiratory training system based on a micro electromechanical system (MEMS) and evaluated the feasibility of the MEMS in radiotherapy. By comparing the measured signal before and after radiation exposure, we confirmed the effects of radiation. By evaluating the period of the electric signal emitted by a tactile sensor and its constancy, the performance of the tactile sensor was confirmed. Moreover, by comparing the delay between the motion of the MEMS and the electric signal from the tactile sensor, we confirmed the reaction time of the tactile sensor. The results showed that a baseline shift occurred for an accumulated dose of 400 Gy in the sensor, and both the amplitude and period changed. The period of the signal released by the tactile sensor was 5.39 and its standard deviation was 0.06. Considering the errors from the motion phantom, a standard deviation of 0.06 was desirable. The delay time was within 0.5 s and not distinguishable by a patient. We confirmed the performance of the MEMS and concluded that MEMS could be applied to patients for respiratory-gated radiotherapy.

EduGATE - basic examples for educative purpose using the GATE simulation platform.

PubMed

Pietrzyk, Uwe; Zakhnini, Abdelhamid; Axer, Markus; Sauerzapf, Sophie; Benoit, Didier; Gaens, Michaela

2013-02-01

EduGATE is a collection of basic examples to introduce students to the fundamental physical aspects of medical imaging devices. It is based on the GATE platform, which has received a wide acceptance in the field of simulating medical imaging devices including SPECT, PET, CT and also applications in radiation therapy. GATE can be configured by commands, which are, for the sake of simplicity, listed in a collection of one or more macro files to set up phantoms, multiple types of sources, detection device, and acquisition parameters. The aim of the EduGATE is to use all these helpful features of GATE to provide insights into the physics of medical imaging by means of a collection of very basic and simple GATE macros in connection with analysis programs based on ROOT, a framework for data processing. A graphical user interface to define a configuration is also included. Copyright © 2012. Published by Elsevier GmbH.

Estimating Daytime Ecosystem Respiration to Improve Estimates of Gross Primary Production of a Temperate Forest

PubMed Central

Sun, Jinwei; Wu, Jiabing; Guan, Dexin; Yao, Fuqi; Yuan, Fenghui; Wang, Anzhi; Jin, Changjie

2014-01-01

Leaf respiration is an important component of carbon exchange in terrestrial ecosystems, and estimates of leaf respiration directly affect the accuracy of ecosystem carbon budgets. Leaf respiration is inhibited by light; therefore, gross primary production (GPP) will be overestimated if the reduction in leaf respiration by light is ignored. However, few studies have quantified GPP overestimation with respect to the degree of light inhibition in forest ecosystems. To determine the effect of light inhibition of leaf respiration on GPP estimation, we assessed the variation in leaf respiration of seedlings of the dominant tree species in an old mixed temperate forest with different photosynthetically active radiation levels using the Laisk method. Canopy respiration was estimated by combining the effect of light inhibition on leaf respiration of these species with within-canopy radiation. Leaf respiration decreased exponentially with an increase in light intensity. Canopy respiration and GPP were overestimated by approximately 20.4% and 4.6%, respectively, when leaf respiration reduction in light was ignored compared with the values obtained when light inhibition of leaf respiration was considered. This study indicates that accurate estimates of daytime ecosystem respiration are needed for the accurate evaluation of carbon budgets in temperate forests. In addition, this study provides a valuable approach to accurately estimate GPP by considering leaf respiration reduction in light in other ecosystems. PMID:25419844

SU-E-T-217: Intrinsic Respiratory Gating in Small Animal CT

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

Liu, Y; Smith, M; Mistry, N

Purpose: Preclinical animal models of lung cancer can provide a controlled test-bed for testing dose escalation or function-based-treatment-planning studies. However, to extract lung function, i.e. ventilation, one needs to be able to image the lung at different phases of ventilation (in-hale / ex-hale). Most respiratory-gated imaging using micro-CT involves using an external ventilator and surgical intervention limiting the utility in longitudinal studies. A new intrinsic respiratory retrospective gating method was developed and tested in mice. Methods: A fixed region of interest (ROI) that covers the diaphragm was selected on all projection images to estimate the mean intensity (M). The meanmore » intensity depends on the projection angle and diaphragm position. A 3-point moving average (A) of consecutive M values: Mpre, Mcurrent and Mpost, was calculated to be subtracted from Mcurrent. A fixed threshold was used to enable amplitude based sorting into 4 different phases of respiration. Images at full-inhale and end-exhale phases of respiration were reconstructed using the open source OSCaR. Lung volumes estimated at the 2 phases of respiration were validated against literature values. Results: Intrinsic retrospective gating was accomplished without the use of any external breathing waveform. While projection images were acquired at 360 different angles. Only 138 and 104 projections were used to reconstruct images at full-inhale and end-exhale. This often results in non-uniform under-sampled angular projections leading to some minor streaking artifacts. The calculated expiratory, inspiratory and tidal lung volumes correlated well with the values known from the literature. Conclusion: Our initial result demonstrates an intrinsic gating method that is suitable for flat panel cone beam small animal CT systems. Reduction in streaking artifacts can be accomplished by oversampling the data or using iterative reconstruction methods. This initial experience will enable

Increases in intracellular pH facilitate endocytosis and decrease availability of voltage-gated proton channels in osteoclasts and microglia

PubMed Central

Sakai, Hiromu; Li, Guangshuai; Hino, Yoshiko; Moriura, Yoshie; Kawawaki, Junko; Sawada, Makoto; Kuno, Miyuki

2013-01-01

Voltage-gated proton channels (H+ channels) are highly proton-selective transmembrane pathways. Although the primary determinants for activation are the pH and voltage gradients across the membrane, the current amplitudes fluctuate often when these gradients are constant. The aim of this study was to investigate the role of the intracellular pH (pHi) in regulating the availability of H+ channels in osteoclasts and microglia. In whole-cell clamp recordings, the pHi was elevated after exposure to NH4Cl and returned to the control level after washout. However, the H+ channel conductance did not recover fully when the exposure was prolonged (>5 min). Similar results were observed in osteoclasts and microglia, but not in COS7 cells expressing a murine H+ channel gene (mVSOP). As other electrophysiological properties, like the gating kinetics and voltage dependence for activation, were unchanged, the decreases in the H+ channel conductance were probably due to the decreases in H+ channels available at the plasma membrane. The decreases in the H+ channel conductances were accompanied by reductions in the cell capacitance. Exposure to NH4Cl increased the uptake of the endocytosis marker FM1-43, substantiating the idea that pHi increases facilitated endocytosis. In osteoclasts, whose plasma membrane expresses V-ATPases and H+ channels, pHi increases by these H+-transferring molecules in part facilitated endocytosis. The endocytosis and decreases in the H+ channel conductance were reduced by dynasore, a dynamin blocker. These results suggest that pHi increases in osteoclasts and microglia decrease the numbers of H+ channels available at the plasma membrane through facilitation of dynamin-dependent endocytosis. PMID:24081153

SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

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

Xie, X; Cao, D; Housley, D

2014-06-01

Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-movingmore » platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.« less

4D micro-CT using fast prospective gating

NASA Astrophysics Data System (ADS)

Guo, Xiaolian; Johnston, Samuel M.; Qi, Yi; Johnson, G. Allan; Badea, Cristian T.

2012-01-01

radiation dose associated with the proposed method is in the range of a typical micro-CT dose (256 mGy for the cardiac study). Ignoring respiration does not significantly affect anatomic information in cardiac studies. FPG can deliver short scan times with low-dose 4D micro-CT imaging without sacrificing image quality. FPG can be applied in high-throughput longitudinal studies in a wide range of applications, including drug safety and cardiopulmonary phenotyping.

Issues in quantification of registered respiratory gated PET/CT in the lung

NASA Astrophysics Data System (ADS)

Cuplov, Vesna; Holman, Beverley F.; McClelland, Jamie; Modat, Marc; Hutton, Brian F.; Thielemans, Kris

2018-01-01

PET/CT quantification of lung tissue is limited by several difficulties: the lung density and local volume changes during respiration, the anatomical mismatch between PET and CT and the relative contributions of tissue, air and blood to the PET signal (the tissue fraction effect). Air fraction correction (AFC) has been shown to improve PET image quantification in the lungs. Methods to correct for the movement and anatomical mismatch involve respiratory gating and image registration techniques. While conventional registration methods only account for spatial mismatch, the Jacobian determinant of the deformable registration transformation field can be used to estimate local volume changes and could therefore potentially be used to correct (i.e. Jacobian Correction, JC) the PET signal for changes in concentration due to local volume changes. This work aims to investigate the relationship between variations in the lung due to respiration, specifically density, tracer concentration and local volume changes. In particular, we study the effect of AFC and JC on PET quantitation after registration of respiratory gated PET/CT patient data. Six patients suffering from lung cancer with solitary pulmonary nodules underwent 18 F-FDG PET/cine-CT. The PET data were gated into six respiratory gates using displacement gating based on a real-time position management (RPM) signal and reconstructed with matched gated CT. The PET tracer concentration and tissue density were extracted from registered gated PET and CT images before and after corrections (AFC or JC) and compared to the values from the reference images. Before correction, we observed a linear correlation between the PET tracer concentration values and density. Across all gates and patients, the maximum relative change in PET tracer concentration before (after) AFC was found to be 16.2% (4.1%) and the maximum relative change in tissue density and PET tracer concentration before (after) JC was found to be 17.1% (5.5%) and 16

30 CFR 57.5044 - Respirators.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

30 CFR 57.5044 - Respirators.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

30 CFR 57.5044 - Respirators.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

30 CFR 57.5044 - Respirators.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

30 CFR 57.5044 - Respirators.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

Analysis of Carina Position as Surrogate Marker for Delivering Phase-Gated Radiotherapy

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

Weide, Lineke van der; Soernsen de Koste, John R. van; Lagerwaard, Frank J.

2008-07-15

Purpose: Respiratory gating can mitigate the effect of tumor mobility in radiotherapy (RT) for lung cancer. Because the tumor is generally not visualized, external surrogates of tumor position are used to trigger respiration-gated RT. We evaluated the suitability of the carina position as a surrogate in respiration-gated RT. Methods and Materials: A total of 30 four-dimensional (4D) computed tomography (CT) scans from 14 patients with lung cancer were retrospectively analyzed. Both uncoached (free breathing) and audio-coached 4D-CT scans were acquired from 9 patients, and 12 uncoached 4D-CT scans were acquired from 5 other patients during a 2-4-week period of stereotacticmore » RT. The repeat scans were co-registered. The carina position was identified on the coronal cut planes in all 4D-CT phases. The correlation between the carina position and the total lung volume for each phase was determined, and the reproducibility of the carina position was studied in the 5 patients with repeat uncoached 4D-CT scans. Results: The mean extent of carina motion in 21 uncoached scans was 5.3 {+-} 1.6 mm in the craniocaudal (CC), 2.3 {+-} 1.4 mm in the anteroposterior, and 1.5 {+-} 0.7 mm in the mediolateral direction. Audio coaching resulted in a twofold increase in carina mobility in all directions. The CC carina position correlated with changes in the total lung volume (R = 0.89 {+-} 0.14), but the correlation was better for the audio-coached than for the uncoached 4D-CT scans (R = 0.93 {+-} 0.08 vs. R = 0.85 {+-} 0.17; paired t test, p = 0.034). Preliminary data from the 5 patients indicated that the CC carina motion correlated better with tumor motion than did the motion of the diaphragm. Conclusions: The CC position of the carina correlated well with the total lung volume, indicating that the carina is a good surrogate for verifying the total lung volume during respiration-gated RT.« less

Voltage-gated Proton Channels

PubMed Central

DeCoursey, Thomas E.

2014-01-01

Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

Optically gated beating-heart imaging

PubMed Central

Taylor, Jonathan M.

2014-01-01

The constant motion of the beating heart presents an obstacle to clear optical imaging, especially 3D imaging, in small animals where direct optical imaging would otherwise be possible. Gating techniques exploit the periodic motion of the heart to computationally “freeze” this movement and overcome motion artifacts. Optically gated imaging represents a recent development of this, where image analysis is used to synchronize acquisition with the heartbeat in a completely non-invasive manner. This article will explain the concept of optical gating, discuss a range of different implementation strategies and their strengths and weaknesses. Finally we will illustrate the usefulness of the technique by discussing applications where optical gating has facilitated novel biological findings by allowing 3D in vivo imaging of cardiac myocytes in their natural environment of the beating heart. PMID:25566083

Accumulation of Mn(II) in Deinococcus radiodurans Facilitates Gamma-Radiation Resistance

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

Daly, Michael J.; Gaidamakova, E; Matrosova, V

2004-11-05

Deinococcus radiodurans is extremely resistant to ionizing radiation. How this bacterium can grow under chronic gamma-radiation (50 Gy/hour) or recover from acute doses greater than 10 kGy is unknown. We show that D. radiodurans accumulates very high intracellular manganese and low iron levels compared to radiation sensitive bacteria, and resistance exhibits a concentration-dependent response to Mn(II). Among the most radiation-resistant bacterial groups reported, Deinococcus, Enterococcus, Lactobacillus and cyanobacteria spp. accumulate Mn(II). In contrast, Shewanella oneidensis and Pseudomonas putida have high Fe but low intracellular Mn concentrations and are very sensitive. We propose that Mn(II) accumulation facilitates recovery from radiation injury.

In vivo self-gated 23 Na MRI at 7 T using an oval-shaped body resonator.

PubMed

Platt, Tanja; Umathum, Reiner; Fiedler, Thomas M; Nagel, Armin M; Bitz, Andreas K; Maier, Florian; Bachert, Peter; Ladd, Mark E; Wielpütz, Mark O; Kauczor, Hans-Ulrich; Behl, Nicolas G R

2018-02-09

This work faces three challenges of sodium ( 23 Na) torso MRI on the way to quantitative 23 Na MRI: Development of a 23 Na radiofrequency transmit and receive coil covering a large part of the human body in width and length for 23 Na MRI at 7 T; reduction of blurring due to respiration in free-breathing 23 Na MRI using a self-gating approach; and reduction of image noise using a compressed-sensing reconstruction. An oval-shaped birdcage resonator with a large field of view of (400 mm) 3 and a homogeneous transmit and receive field distribution was designed, simulated, and implemented on a 7T MR system. In free-breathing 3-dimensional radial 23 Na MRI (acquisition time ≈ 30 minutes), retrospective respiratory self-gating was applied, which sorts the acquired projections into two respiratory states based on the intrinsic respiration-dependent signal changes. Furthermore, a 3-dimensional dictionary-learning compressed-sensing reconstruction was applied. The developed body coil provided homogeneous radiofrequency excitation (flip angle error of 4.9% in central region of interest of 23 × 13 × 10 cm 3 ) and homogeneous signal reception. The self-gating approach allowed for separation of the full data set into two subsets associated with different respiratory states (inhaled and exhaled), and thereby reduced blurring due to respiration in the separated images. Image noise was markedly reduced by the compressed-sensing algorithm. The presented body coil enables full body width 23 Na MRI with long z-axis coverage at 7 T for the first time. Additionally, the retrospective respiratory self-gating performance is demonstrated for free-breathing lung and abdominal 23 Na MRI in 3 subjects. © 2018 International Society for Magnetic Resonance in Medicine.

Accurate respiration measurement using DC-coupled continuous-wave radar sensor for motion-adaptive cancer radiotherapy.

PubMed

Gu, Changzhan; Li, Ruijiang; Zhang, Hualiang; Fung, Albert Y C; Torres, Carlos; Jiang, Steve B; Li, Changzhi

2012-11-01

Accurate respiration measurement is crucial in motion-adaptive cancer radiotherapy. Conventional methods for respiration measurement are undesirable because they are either invasive to the patient or do not have sufficient accuracy. In addition, measurement of external respiration signal based on conventional approaches requires close patient contact to the physical device which often causes patient discomfort and undesirable motion during radiation dose delivery. In this paper, a dc-coupled continuous-wave radar sensor was presented to provide a noncontact and noninvasive approach for respiration measurement. The radar sensor was designed with dc-coupled adaptive tuning architectures that include RF coarse-tuning and baseband fine-tuning, which allows the radar sensor to precisely measure movement with stationary moment and always work with the maximum dynamic range. The accuracy of respiration measurement with the proposed radar sensor was experimentally evaluated using a physical phantom, human subject, and moving plate in a radiotherapy environment. It was shown that respiration measurement with radar sensor while the radiation beam is on is feasible and the measurement has a submillimeter accuracy when compared with a commercial respiration monitoring system which requires patient contact. The proposed radar sensor provides accurate, noninvasive, and noncontact respiration measurement and therefore has a great potential in motion-adaptive radiotherapy.

Self-Gated Late Gadolinium Enhancement at 7T to Image Rats with Reperfused Acute Myocardial Infarction.

PubMed

Wang, Lei; Chen, Yushu; Zhang, Bing; Chen, Wei; Wang, Chunhua; Song, Li; Xu, Ziqian; Zheng, Jie; Gao, Fabao

2018-01-01

A failed electrocardiography (ECG)-trigger often leads to a long acquisition time (TA) and deterioration in image quality. The purpose of this study was to evaluate and optimize the technique of self-gated (SG) cardiovascular magnetic resonance (CMR) for cardiac late gadolinium enhancement (LGE) imaging of rats with myocardial infarction/reperfusion. Cardiovascular magnetic resonance images of 10 rats were obtained using SG-LGE or ECG with respiration double-gating (ECG-RESP-gating) method at 7T to compare differences in image interference and TA between the two methods. A variety of flip angles (FA: 10°-80°) and the number of repetitions (NR: 40, 80, 150, and 300) were investigated to determine optimal scan parameters of SG-LGE technique based on image quality score and contrast-to-noise ratio (CNR). Self-gated late gadolinium enhancement allowed successful scan in 10 (100%) rats. However, only 4 (40%) rats were successfully scanned with the ECG-RESP-gating method. TAs with SG-LGE varied depending on NR used (TA: 41, 82, 154, and 307 seconds, corresponding to NR of 40, 80, 150, and 300, respectively). For the ECG-RESP-gating method, the average TA was 220 seconds. For SG-LGE images, CNR (42.5 ± 5.5, 43.5 ± 7.5, 54 ± 9, 59.5 ± 8.5, 56 ± 13, 54 ± 8, and 41 ± 9) and image quality score (1.85 ± 0.75, 2.20 ± 0.83, 2.85 ± 0.37, 3.85 ± 0.52, 2.8 ± 0.51, 2.45 ± 0.76, and 1.95 ± 0.60) were achieved with different FAs (10°, 15°, 20°, 25°, 30°, 35°, and 40°, respectively). Optimal FAs of 20°-30° and NR of 80 were recommended. Self-gated technique can improve image quality of LGE without irregular ECG or respiration gating. Therefore, SG-LGE can be used an alternative method of ECG-RESP-gating.

Issues in quantification of registered respiratory gated PET/CT in the lung.

PubMed

Cuplov, Vesna; Holman, Beverley F; McClelland, Jamie; Modat, Marc; Hutton, Brian F; Thielemans, Kris

2017-12-14

PET/CT quantification of lung tissue is limited by several difficulties: the lung density and local volume changes during respiration, the anatomical mismatch between PET and CT and the relative contributions of tissue, air and blood to the PET signal (the tissue fraction effect). Air fraction correction (AFC) has been shown to improve PET image quantification in the lungs. Methods to correct for the movement and anatomical mismatch involve respiratory gating and image registration techniques. While conventional registration methods only account for spatial mismatch, the Jacobian determinant of the deformable registration transformation field can be used to estimate local volume changes and could therefore potentially be used to correct (i.e. Jacobian Correction, JC) the PET signal for changes in concentration due to local volume changes. This work aims to investigate the relationship between variations in the lung due to respiration, specifically density, tracer concentration and local volume changes. In particular, we study the effect of AFC and JC on PET quantitation after registration of respiratory gated PET/CT patient data. Six patients suffering from lung cancer with solitary pulmonary nodules underwent [Formula: see text]F-FDG PET/cine-CT. The PET data were gated into six respiratory gates using displacement gating based on a real-time position management (RPM) signal and reconstructed with matched gated CT. The PET tracer concentration and tissue density were extracted from registered gated PET and CT images before and after corrections (AFC or JC) and compared to the values from the reference images. Before correction, we observed a linear correlation between the PET tracer concentration values and density. Across all gates and patients, the maximum relative change in PET tracer concentration before (after) AFC was found to be 16.2% (4.1%) and the maximum relative change in tissue density and PET tracer concentration before (after) JC was found to be 17

Shrubs stimulate heterotrophic respiration in arctic soils

NASA Astrophysics Data System (ADS)

Phillips, C. A.; Wurzburger, N.

2016-12-01

The response of arctic ecosystems to global change will have critical effects on future climate. Climate warming has already triggered the expansion of shrubs across tundra, raising questions about how shrubs will affect ecosystem carbon balance. Shrub litter quality and mycorrhizal symbionts may accelerate the activity of soil microorganisms that facilitate the release of large stores of soil carbon. We investigated how shrubs affect the activity of soil microorganisms by creating soil mesocosms from areas with and without shrub species as dominants of the plant community in arctic Alaska. We hypothesized that relative to their non-shrub counterparts, heterotrophic respiration of shrub soils would: (1) be greater, (2) demonstrate greater response to additions of shrub litter, and (3) be less nutrient limited. We created mesocosms with root-free soils at constant moisture and temperature, and quantified basal heterotrophic soil respiration rates, and the response of respiration to litter and nutrient inputs in a series of laboratory experiments inputs. (1) We found that the presence of shrubs generally produced higher rates of basal soil respiration in both horizons, suggesting that shrubs stimulate microbial activity. (2) Litter addition increased respiration across both horizons with no differences in response between shrub and non-shrub soils. (3) N additions did not increase heterotrophic respiration, but P and N+P additions induced a short respiratory pulse in all soils, suggesting mild P limitation. Collectively, these findings provide evidence that shrubs stimulate heterotrophic microbial activity to enhance carbon loss, but generate new questions about the mechanisms driving these patterns.

GUI to Facilitate Research on Biological Damage from Radiation

NASA Technical Reports Server (NTRS)

Cucinotta, Frances A.; Ponomarev, Artem Lvovich

2010-01-01

A graphical-user-interface (GUI) computer program has been developed to facilitate research on the damage caused by highly energetic particles and photons impinging on living organisms. The program brings together, into one computational workspace, computer codes that have been developed over the years, plus codes that will be developed during the foreseeable future, to address diverse aspects of radiation damage. These include codes that implement radiation-track models, codes for biophysical models of breakage of deoxyribonucleic acid (DNA) by radiation, pattern-recognition programs for extracting quantitative information from biological assays, and image-processing programs that aid visualization of DNA breaks. The radiation-track models are based on transport models of interactions of radiation with matter and solution of the Boltzmann transport equation by use of both theoretical and numerical models. The biophysical models of breakage of DNA by radiation include biopolymer coarse-grained and atomistic models of DNA, stochastic- process models of deposition of energy, and Markov-based probabilistic models of placement of double-strand breaks in DNA. The program is designed for use in the NT, 95, 98, 2000, ME, and XP variants of the Windows operating system.

Effect of respiratory and cardiac gating on the major diffusion-imaging metrics

PubMed Central

Hamaguchi, Hiroyuki; Sugimori, Hiroyuki; Nakanishi, Mitsuhiro; Nakagawa, Shin; Fujiwara, Taro; Yoshida, Hirokazu; Takamori, Sayaka; Shirato, Hiroki

2016-01-01

The effect of respiratory gating on the major diffusion-imaging metrics and that of cardiac gating on mean kurtosis (MK) are not known. For evaluation of whether the major diffusion-imaging metrics—MK, fractional anisotropy (FA), and mean diffusivity (MD) of the brain—varied between gated and non-gated acquisitions, respiratory-gated, cardiac-gated, and non-gated diffusion-imaging of the brain were performed in 10 healthy volunteers. MK, FA, and MD maps were constructed for all acquisitions, and the histograms were constructed. The normalized peak height and location of the histograms were compared among the acquisitions by use of Friedman and post hoc Wilcoxon tests. The effect of the repetition time (TR) on the diffusion-imaging metrics was also tested, and we corrected for its variation among acquisitions, if necessary. The results showed a shift in the peak location of the MK and MD histograms to the right with an increase in TR (p ≤ 0.01). The corrected peak location of the MK histograms, the normalized peak height of the FA histograms, the normalized peak height and the corrected peak location of the MD histograms varied significantly between the gated and non-gated acquisitions (p < 0.05). These results imply an influence of respiration and cardiac pulsation on the major diffusion-imaging metrics. The gating conditions must be kept identical if reproducible results are to be achieved. PMID:27073115

Effect of respiratory and cardiac gating on the major diffusion-imaging metrics.

PubMed

Hamaguchi, Hiroyuki; Tha, Khin Khin; Sugimori, Hiroyuki; Nakanishi, Mitsuhiro; Nakagawa, Shin; Fujiwara, Taro; Yoshida, Hirokazu; Takamori, Sayaka; Shirato, Hiroki

2016-08-01

The effect of respiratory gating on the major diffusion-imaging metrics and that of cardiac gating on mean kurtosis (MK) are not known. For evaluation of whether the major diffusion-imaging metrics-MK, fractional anisotropy (FA), and mean diffusivity (MD) of the brain-varied between gated and non-gated acquisitions, respiratory-gated, cardiac-gated, and non-gated diffusion-imaging of the brain were performed in 10 healthy volunteers. MK, FA, and MD maps were constructed for all acquisitions, and the histograms were constructed. The normalized peak height and location of the histograms were compared among the acquisitions by use of Friedman and post hoc Wilcoxon tests. The effect of the repetition time (TR) on the diffusion-imaging metrics was also tested, and we corrected for its variation among acquisitions, if necessary. The results showed a shift in the peak location of the MK and MD histograms to the right with an increase in TR (p ≤ 0.01). The corrected peak location of the MK histograms, the normalized peak height of the FA histograms, the normalized peak height and the corrected peak location of the MD histograms varied significantly between the gated and non-gated acquisitions (p < 0.05). These results imply an influence of respiration and cardiac pulsation on the major diffusion-imaging metrics. The gating conditions must be kept identical if reproducible results are to be achieved. © The Author(s) 2016.

Motion-gated acquisition for in vivo optical imaging

PubMed Central

Gioux, Sylvain; Ashitate, Yoshitomo; Hutteman, Merlijn; Frangioni, John V.

2009-01-01

Wide-field continuous wave fluorescence imaging, fluorescence lifetime imaging, frequency domain photon migration, and spatially modulated imaging have the potential to provide quantitative measurements in vivo. However, most of these techniques have not yet been successfully translated to the clinic due to challenging environmental constraints. In many circumstances, cardiac and respiratory motion greatly impair image quality and∕or quantitative processing. To address this fundamental problem, we have developed a low-cost, field-programmable gate array–based, hardware-only gating device that delivers a phase-locked acquisition window of arbitrary delay and width that is derived from an unlimited number of pseudo-periodic and nonperiodic input signals. All device features can be controlled manually or via USB serial commands. The working range of the device spans the extremes of mouse electrocardiogram (1000 beats per minute) to human respiration (4 breaths per minute), with timing resolution ⩽0.06%, and jitter ⩽0.008%, of the input signal period. We demonstrate the performance of the gating device, including dramatic improvements in quantitative measurements, in vitro using a motion simulator and in vivo using near-infrared fluorescence angiography of beating pig heart. This gating device should help to enable the clinical translation of promising new optical imaging technologies. PMID:20059276

SU-E-T-651: Quantification of Dosimetric Accuracy of Respiratory Gated Stereotactic Body Radiation Therapy

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

Thiyagarajan, Rajesh; Vikraman, S; Maragathaveni, S

2015-06-15

Purpose: To quantify the dosimetric accuracy of respiratory gated stereotactic body radiation therapy delivery using dynamic thorax phantom. Methods: Three patients with mobile target (2 lung, 1liver) were chosen. Retrospective 4DCT image sets were acquired for using Varian RPM system. An in-house MATLAB program was designed for MIP, MinIP and AvgIP generation. ITV was contoured on MIP image set for lung patients and on MinIP for liver patient. Dynamic IMRT plans were generated on selected phase bin image set in Eclipse (v10.0) planning system. CIRS dynamic thorax phantom was used to perform the dosimetric quality assurance. Patient breathing pattern filemore » from RPM system was converted to phantom compatible file by an in-house MATLAB program. This respiratory pattern fed to the CIRS dynamic thorax phantom. 4DCT image set was acquired for this phantom using patient breathing pattern. Verification plans were generated using patient gating window and delivered on the phantom. Measurements were carried out using with ion chamber and EBT2 film. Exposed films were analyzed and evaluated in FilmQA software. Results: The stability of gated output in comparison with un-gated output was within 0.5%. The Ion chamber measured and TPS calculated dose compared for all the patients. The difference observed was 0.45%, −0.52% and −0.54 for Patient 1, Patient2 and Patient 3 respectively.Gamma value evaluated from EBT film shows pass rates from 92.41% to 99.93% for 3% dose difference and 3mm distance to agreement criteria. Conclusion: Dosimetric accuracy of respiratory gated SBRT delivery for lung and liver was dosimetrically acceptable. The Ion chamber measured dose was within 0.203±0.5659% of the expected dose. Gamma pass rates were within 96.63±3.84% of the expected dose.« less

Single-Event Gate Rupture in Power MOSFETs: A New Radiation Hardness Assurance Approach

NASA Technical Reports Server (NTRS)

Lauenstein, Jean-Marie

2011-01-01

Almost every space mission uses vertical power metal-semiconductor-oxide field-effect transistors (MOSFETs) in its power-supply circuitry. These devices can fail catastrophically due to single-event gate rupture (SEGR) when exposed to energetic heavy ions. To reduce SEGR failure risk, the off-state operating voltages of the devices are derated based upon radiation tests at heavy-ion accelerator facilities. Testing is very expensive. Even so, data from these tests provide only a limited guide to on-orbit performance. In this work, a device simulation-based method is developed to measure the response to strikes from heavy ions unavailable at accelerator facilities but posing potential risk on orbit. This work is the first to show that the present derating factor, which was established from non-radiation reliability concerns, is appropriate to reduce on-orbit SEGR failure risk when applied to data acquired from ions with appropriate penetration range. A second important outcome of this study is the demonstration of the capability and usefulness of this simulation technique for augmenting SEGR data from accelerator beam facilities. The mechanisms of SEGR are two-fold: the gate oxide is weakened by the passage of the ion through it, and the charge ionized along the ion track in the silicon transiently increases the oxide electric field. Most hardness assurance methodologies consider the latter mechanism only. This work demonstrates through experiment and simulation that the gate oxide response should not be neglected. In addition, the premise that the temporary weakening of the oxide due to the ion interaction with it, as opposed to due to the transient oxide field generated from within the silicon, is validated. Based upon these findings, a new approach to radiation hardness assurance for SEGR in power MOSFETs is defined to reduce SEGR risk in space flight projects. Finally, the potential impact of accumulated dose over the course of a space mission on SEGR

Preliminary analysis for integration of spot-scanning proton beam therapy and real-time imaging and gating.

PubMed

Shimizu, S; Matsuura, T; Umezawa, M; Hiramoto, K; Miyamoto, N; Umegaki, K; Shirato, H

2014-07-01

Spot-scanning proton beam therapy (PBT) can create good dose distribution for static targets. However, there exists larger uncertainty for tumors that move due to respiration, bowel gas or other internal circumstances within the patients. We have developed a real-time tumor-tracking radiation therapy (RTRT) system that uses an X-ray linear accelerator gated to the motion of internal fiducial markers introduced in the late 1990s. Relying on more than 10 years of clinical experience and big log data, we established a real-time image gated proton beam therapy system dedicated to spot scanning. Using log data and clinical outcomes derived from the clinical usage of the RTRT system since 1999, we have established a library to be used for in-house simulation for tumor targeting and evaluation. Factors considered to be the dominant causes of the interplay effects related to the spot scanning dedicated proton therapy system are listed and discussed. Total facility design, synchrotron operation cycle, and gating windows were listed as the important factors causing the interplay effects contributing to the irradiation time and motion-induced dose error. Fiducial markers that we have developed and used for the RTRT in X-ray therapy were suggested to have the capacity to improve dose distribution. Accumulated internal motion data in the RTRT system enable us to improve the operation and function of a Spot-scanning proton beam therapy (SSPT) system. A real-time-image gated SSPT system can increase accuracy for treating moving tumors. The system will start clinical service in early 2014. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

SU-E-E-11: Novel Matching Module for Respiration-Gated Motion Tumor of Cone-Beam Computed Tomography (CBCT) to 4DCT

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

Yu, P; Tsai, Y; Nien, H

2015-06-15

Purpose: Four dimensional computed tomography (4DCT) scans reliably record whole respiratory phase and generate internal target volumes (ITV) for radiotherapy planning. However, image guiding with cone-beam computed tomography (CBCT) cannot acquire all or specific respiratory phases. This study was designed to investigate the correlation between average CT and Maximum Intensity Projection (MIP) from 4DCT and CBCT. Methods: Retrospective respiratory gating were performed by GE Discovery CT590 RT. 4DCT and CBCT data from CRIS Dynamic Thorax Phantom with simulated breathing mode were analyzed. The lung tissue equivalent material encompassed 3 cm sphere tissue equivalent material. Simulated breathing cycle period was setmore » as 4 seconds, 5 seconds and 6 seconds for representing variation of patient breathing cycle time, and the sphere material moved toward inferior and superior direction with 1 cm amplitude simulating lung tumor motion during respiration. Results: Under lung window, the volume ratio of CBCT scans to ITVs derived from 10 phases average scans was 1.00 ± 0.02, and 1.03 ± 0.03 for ratio of CBCT scans to MIP scans. Under abdomen window, the ratio of CBCT scans to ITVs derived from 10 phases average scans was 0.39 ± 0.06, and 0.06 ± 0.00 for ratio of CBCT scans to MIP scans. There was a significant difference between lung window Result and abdomen window Result. For reducing image guiding uncertainty, CBCT window was set with width 500 and level-250. The ratio of CBCT scans to ITVs derived from 4 phases average scans with abdomen window was 1.19 ± 0.02, and 1.06 ± 0.01 for ratio of CBCT to MIP scans. Conclusion: CBCT images with suitable window width and level can efficiently reduce image guiding uncertainty for patient with mobile tumor. By our setting, we can match motion tumor to gating tumor location on planning CT more accurately neglecting other motion artifacts during CBCT scans.« less

Ionizing radiation detector

DOEpatents

Thacker, Louis H.

1990-01-01

An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Radiation Effects in Advanced Multiple Gate and Silicon-on-Insulator Transistors

NASA Astrophysics Data System (ADS)

Simoen, Eddy; Gaillardin, Marc; Paillet, Philippe; Reed, Robert A.; Schrimpf, Ron D.; Alles, Michael L.; El-Mamouni, Farah; Fleetwood, Daniel M.; Griffoni, Alessio; Claeys, Cor

2013-06-01

The aim of this review paper is to describe in a comprehensive manner the current understanding of the radiation response of state-of-the-art Silicon-on-Insulator (SOI) and FinFET CMOS technologies. Total Ionizing Dose (TID) response, heavy-ion microdose effects and single-event effects (SEEs) will be discussed. It is shown that a very high TID tolerance can be achieved by narrow-fin SOI FinFET architectures, while bulk FinFETs may exhibit similar TID response to the planar devices. Due to the vertical nature of FinFETs, a specific heavy-ion response can be obtained, whereby the angle of incidence becomes highly important with respect to the vertical sidewall gates. With respect to SEE, the buried oxide in the SOI FinFETs suppresses the diffusion tails from the charge collection in the substrate compared to the planar bulk FinFET devices. Channel lengths and fin widths are now comparable to, or smaller than the dimensions of the region affected by the single ionizing ions or lasers used in testing. This gives rise to a high degree of sensitivity to individual device parameters and source-drain shunting during ion-beam or laser-beam SEE testing. Simulations are used to illuminate the mechanisms observed in radiation testing and the progress and needs for the numerical modeling/simulation of the radiation response of advanced SOI and FinFET transistors are highlighted.

Respirable dust and respirable silica exposure in Ontario gold mines.

PubMed

Verma, Dave K; Rajhans, Gyan S; Malik, Om P; des Tombe, Karen

2014-01-01

A comprehensive survey of respirable dust and respirable silica in Ontario gold mines was conducted by the Ontario Ministry of Labor during 1978-1979. The aim was to assess the feasibility of introducing gravimetric sampling to replace the assessment method which used konimeters, a device which gave results in terms of number of particles per cubic centimeter (ppcc) of air. The study involved both laboratory and field assessments. The field assessment involved measurement of airborne respirable dust and respirable silica at all eight operating gold mines of the time. This article describes the details of the field assessment. A total of 288 long-term (7-8 hr) personal respirable dust air samples were collected from seven occupational categories in eight gold mines. The respirable silica (α-quartz) was determined by x-ray diffraction method. The results show that during 1978-1979, the industry wide mean respirable dust was about 1 mg/m(3), and the mean respirable silica was 0.08 mg/m(3.)The mean% silica in respirable dust was 7.5%. The data set would be useful in future epidemiological and health studies, as well as in assessment of workers' compensation claims for occupational diseases such as silicosis, chronic obstructive pulmonary disease (COPD), and autoimmune diseases such as renal disease and rheumatoid arthritis.

SIFT-based dense pixel tracking on 0.35 T cine-MR images acquired during image-guided radiation therapy with application to gating optimization

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

Mazur, Thomas R., E-mail: tmazur@radonc.wustl.edu, E-mail: hli@radonc.wustl.edu; Fischer-Valuck, Benjamin W.; Wang, Yuhe

Purpose: To first demonstrate the viability of applying an image processing technique for tracking regions on low-contrast cine-MR images acquired during image-guided radiation therapy, and then outline a scheme that uses tracking data for optimizing gating results in a patient-specific manner. Methods: A first-generation MR-IGRT system—treating patients since January 2014—integrates a 0.35 T MR scanner into an annular gantry consisting of three independent Co-60 sources. Obtaining adequate frame rates for capturing relevant patient motion across large fields-of-view currently requires coarse in-plane spatial resolution. This study initially (1) investigate the feasibility of rapidly tracking dense pixel correspondences across single, sagittal planemore » images (with both moderate signal-to-noise and spatial resolution) using a matching objective for highly descriptive vectors called scale-invariant feature transform (SIFT) descriptors associated to all pixels that describe intensity gradients in local regions around each pixel. To more accurately track features, (2) harmonic analysis was then applied to all pixel trajectories within a region-of-interest across a short training period. In particular, the procedure adjusts the motion of outlying trajectories whose relative spectral power within a frequency bandwidth consistent with respiration (or another form of periodic motion) does not exceed a threshold value that is manually specified following the training period. To evaluate the tracking reliability after applying this correction, conventional metrics—including Dice similarity coefficients (DSCs), mean tracking errors (MTEs), and Hausdorff distances (HD)—were used to compare target segmentations obtained via tracking to manually delineated segmentations. Upon confirming the viability of this descriptor-based procedure for reliably tracking features, the study (3) outlines a scheme for optimizing gating parameters—including relative target

Estimating Canopy Dark Respiration for Crop Models

NASA Technical Reports Server (NTRS)

Monje Mejia, Oscar Alberto

2014-01-01

Crop production is obtained from accurate estimates of daily carbon gain.Canopy gross photosynthesis (Pgross) can be estimated from biochemical models of photosynthesis using sun and shaded leaf portions and the amount of intercepted photosyntheticallyactive radiation (PAR).In turn, canopy daily net carbon gain can be estimated from canopy daily gross photosynthesis when canopy dark respiration (Rd) is known.

Coronary CT angiography with single-source and dual-source CT: comparison of image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated protocols.

PubMed

Sabarudin, Akmal; Sun, Zhonghua; Yusof, Ahmad Khairuddin Md

2013-09-30

This study is conducted to investigate and compare image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated coronary CT angiography (CCTA) with the use of single-source CT (SSCT) and dual-source CT (DSCT). A total of 209 patients who underwent CCTA with suspected coronary artery disease scanned with SSCT (n=95) and DSCT (n=114) scanners using prospective ECG-triggered and retrospective ECG-gated protocols were recruited from two institutions. The image was assessed by two experienced observers, while quantitative assessment was performed by measuring the image noise, the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR). Effective dose was calculated using the latest published conversion coefficient factor. A total of 2087 out of 2880 coronary artery segments were assessable, with 98.0% classified as of sufficient and 2.0% as of insufficient image quality for clinical diagnosis. There was no significant difference in overall image quality between prospective ECG-triggered and retrospective gated protocols, whether it was performed with DSCT or SSCT scanners. Prospective ECG-triggered protocol was compared in terms of radiation dose calculation between DSCT (6.5 ± 2.9 mSv) and SSCT (6.2 ± 1.0 mSv) scanners and no significant difference was noted (p=0.99). However, the effective dose was significantly lower with DSCT (18.2 ± 8.3 mSv) than with SSCT (28.3 ± 7.0 mSv) in the retrospective gated protocol. Prospective ECG-triggered CCTA reduces radiation dose significantly compared to retrospective ECG-gated CCTA, while maintaining good image quality. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

A comparison study: image-based vs signal-based retrospective gating on microCT

NASA Astrophysics Data System (ADS)

Liu, Xuan; Salmon, Phil L.; Laperre, Kjell; Sasov, Alexander

2017-09-01

Retrospective gating on animal studies with microCT has gained popularity in recent years. Previously, we use ECG signals for cardiac gating and breathing airflow or video signals of abdominal motion for respiratory gating. This method is adequate and works well for most applications. However, through the years, researchers have noticed some pitfalls in the method. For example, the additional signal acquisition step may increase failure rate in practice. X-Ray image-based gating, on the other hand, does not require any extra step in the scanning. Therefore we investigate imagebased gating techniques. This paper presents a comparison study of the image-based versus signal-based approach to retrospective gating. The two application areas we have studied are respiratory and cardiac imaging for both rats and mice. Image-based respiratory gating on microCT is relatively straightforward and has been done by several other researchers and groups. This method retrieves an intensity curve of a region of interest (ROI) placed in the lung area on all projections. From scans on our systems based on step-and-shoot scanning mode, we confirm that this method is very effective. A detailed comparison between image-based and signal-based gating methods is given. For cardiac gating, breathing motion is not negligible and has to be dealt with. Another difficulty in cardiac gating is the relatively smaller amplitude of cardiac movements comparing to the respirational movements, and the higher heart rate. Higher heart rate requires high speed image acquisition. We have been working on our systems to improve the acquisition speed. A dual gating technique has been developed to achieve adequate cardiac imaging.

Glutathione-facilitated design and fabrication of gold nanoparticle-based logic gates and keypad lock.

PubMed

Huang, Zhenzhen; Wang, Haonan; Yang, Wensheng

2014-07-21

In this paper, we describe how we developed a simple design and fabrication method for logic gates and a device by using a commercially available tripeptide, namely glutathione (GSH), together with metal ions and disodium ethylenediaminetetraacetate (EDTA) to control the dispersion and aggregation of gold nanoparticles (NPs). With the fast adsorption of GSH on gold NPs and the strong coordination of GSH with metal ions, the addition of GSH and Pb(2+) ions immediately resulted in the aggregation of gold NPs, giving rise to an AND function. Either Pb(2+) or Ba(2+) ions induced the aggregation of gold NPs in the presence of GSH, supporting an OR gate. Based on the fact that EDTA has a strong capacity to bind metal ions, thus preventing the aggregation of gold NPs, an INHIBIT gate was also fabricated. More interestingly, we found that the addition sequence of GSH and Hg(2+) ions influenced the aggregation of gold NPs in a controlled manner, which was used to design a sequential logic gate and a three-input keypad lock for potential use in information security. The GSH strategy addresses concerns of low cost, simple fabrication, versatile design and easy operation, and offers a promising platform for the development of functional logic systems.

SU-E-T-439: Fundamental Verification of Respiratory-Gated Spot Scanning Proton Beam Therapy

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

Hamano, H; Yamakawa, T; Hayashi, N

Purpose: The spot-scanning proton beam irradiation with respiratory gating technique provides quite well dose distribution and requires both dosimetric and geometric verification prior to clinical implementation. The purpose of this study is to evaluate the impact of gating irradiation as a fundamental verification. Methods: We evaluated field width, flatness, symmetry, and penumbra in the gated and non-gated proton beams. The respiration motion was distinguished into 3 patterns: 10, 20, and 30 mm. We compared these contents between the gated and non-gated beams. A 200 MeV proton beam from PROBEAT-III unit (Hitachi Co.Ltd) was used in this study. Respiratory gating irradiationmore » was performed by Quasar phantom (MODUS medical devices) with a combination of dedicated respiratory gating system (ANZAI Medical Corporation). For radiochromic film dosimetry, the calibration curve was created with Gafchromic EBT3 film (Ashland) on FilmQA Pro 2014 (Ashland) as film analysis software. Results: The film was calibrated at the middle of spread out Bragg peak in passive proton beam. The field width, flatness and penumbra in non-gated proton irradiation with respiratory motion were larger than those of reference beam without respiratory motion: the maximum errors of the field width, flatness and penumbra in respiratory motion of 30 mm were 1.75% and 40.3% and 39.7%, respectively. The errors of flatness and penumbra in gating beam (motion: 30 mm, gating rate: 25%) were 0.0% and 2.91%, respectively. The results of symmetry in all proton beams with gating technique were within 0.6%. Conclusion: The field width, flatness, symmetry and penumbra were improved with the gating technique in proton beam. The spot scanning proton beam with gating technique is feasible for the motioned target.« less

Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout.

PubMed

Lee, Min Su; Lee, Hee Chul

2014-01-01

In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results.

Aspect Ratio Model for Radiation-Tolerant Dummy Gate-Assisted n-MOSFET Layout

PubMed Central

Lee, Min Su; Lee, Hee Chul

2014-01-01

In order to acquire radiation-tolerant characteristics in integrated circuits, a dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was adopted. The DGA n-MOSFET has a different channel shape compared with the standard n-MOSFET. The standard n-MOSFET has a rectangular channel shape, whereas the DGA n-MOSFET has an extended rectangular shape at the edge of the source and drain, which affects its aspect ratio. In order to increase its practical use, a new aspect ratio model is proposed for the DGA n-MOSFET and this model is evaluated through three-dimensional simulations and measurements of the fabricated devices. The proposed aspect ratio model for the DGA n-MOSFET exhibits good agreement with the simulation and measurement results. PMID:27350975

SU-F-T-479: Estimation of the Accuracy in Respiratory-Gated Radiotherapy

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

Kurosawa, T; Miyakawa, S; Sato, M

Purpose: Irregular respiratory patterns affects dose outputs in respiratorygated radiotherapy and there is no commercially available quality assurance (QA) system for it. We designed and developed a patient specific QA system for respiratory-gated radiotherapy to estimate irradiated output. Methods: Our in-house QA system for gating was composed of a personal computer with the USB-FSIO electronic circuit connecting to the linear accelerator (ONCOR-K, Toshiba Medical Systems). The linac implements a respiratory gating system (AZ-733V, Anzai Medical). During the beam was on, 4.2 V square-wave pulses were continually sent to the system. Our system can receive and count the pulses. At first,more » our system and an oscilloscope were compared to check the performance of our system. Next, basic estimation models were generated when ionization-chamber measurements were performed in gating using regular sinusoidal wave patterns (2.0, 2.5, 4.0, 8.0, 15 sec/cycle). During gated irradiation with the regular patterns, the number of the pulses per one gating window was measured using our system. Correlation between the number of the pulses per one gating and dose per the gating window were assessed to generate the estimation model. Finally, two irregular respiratory patterns were created and the accuracy of the estimation was evaluated. Results: Compared to the oscilloscope, our system worked similarly. The basic models were generated with the accuracy within 0.1%. The results of the gated irradiations with two irregular respiratory patterns show good agreement within 0.4% estimation accuracy. Conclusion: Our developed system shows good estimation for even irregular respiration patterns. The system would be a useful tool to verify the output for respiratory-gated radiotherapy.« less

Design of a radiation tolerant system for total ionizing dose monitoring using floating gate and RadFET dosimeters

NASA Astrophysics Data System (ADS)

Ferraro, R.; Danzeca, S.; Brucoli, M.; Masi, A.; Brugger, M.; Dilillo, L.

2017-04-01

The need for upgrading the Total Ionizing Dose (TID) measurement resolution of the current version of the Radiation Monitoring system for the LHC complex has driven the research of new TID sensors. The sensors being developed nowadays can be defined as Systems On Chip (SOC) with both analog and digital circuitries embedded in the same silicon. A radiation tolerant TID Monitoring System (TIDMon) has been designed to allow the placement of the entire dosimeter readout electronics in very harsh environments such as calibration rooms and even in the mixed radiation field such as the one of the LHC complex. The objective of the TIDMon is to measure the effect of the TID on the new prototype of Floating Gate Dosimeter (FGDOS) without using long cables and with a reliable measurement system. This work introduces the architecture of the TIDMon, the radiation tolerance techniques applied on the controlling electronics as well as the design choices adopted for the system. Finally, results of several tests of TIDMon under different radiation environments such as gamma rays or mixed radiation field at CHARM are presented.

Floating Gate CMOS Dosimeter With Frequency Output

NASA Astrophysics Data System (ADS)

Garcia-Moreno, E.; Isern, E.; Roca, M.; Picos, R.; Font, J.; Cesari, J.; Pineda, A.

2012-04-01

This paper presents a gamma radiation dosimeter based on a floating gate sensor. The sensor is coupled with a signal processing circuitry, which furnishes a square wave output signal, the frequency of which depends on the total dose. Like any other floating gate dosimeter, it exhibits zero bias operation and reprogramming capabilities. The dosimeter has been designed in a standard 0.6 m CMOS technology. The whole dosimeter occupies a silicon area of 450 m250 m. The initial sensitivity to a radiation dose is Hz/rad, and to temperature and supply voltage is kHz/°C and 0.067 kHz/mV, respectively. The lowest detectable dose is less than 1 rad.

Nanogranular SiO2 proton gated silicon layer transistor mimicking biological synapses

NASA Astrophysics Data System (ADS)

Liu, M. J.; Huang, G. S.; Feng, P.; Guo, Q. L.; Shao, F.; Tian, Z. A.; Li, G. J.; Wan, Q.; Mei, Y. F.

2016-06-01

Silicon on insulator (SOI)-based transistors gated by nanogranular SiO2 proton conducting electrolytes were fabricated to mimic synapse behaviors. This SOI-based device has both top proton gate and bottom buried oxide gate. Electrical transfer properties of top proton gate show hysteresis curves different from those of bottom gate, and therefore, excitatory post-synaptic current and paired pulse facilitation (PPF) behavior of biological synapses are mimicked. Moreover, we noticed that PPF index can be effectively tuned by the spike interval applied on the top proton gate. Synaptic behaviors and functions, like short-term memory, and its properties are also experimentally demonstrated in our device. Such SOI-based electronic synapses are promising for building neuromorphic systems.

10 CFR Appendix A to Part 20 - Assigned Protection Factors for Respirators a

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Assigned Protection Factors for Respirators a A Appendix A to Part 20 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Pt. 20.... External radiation hazards and other limitations to permitted exposure such as skin absorption shall be...

10 CFR Appendix A to Part 20 - Assigned Protection Factors for Respirators a

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Assigned Protection Factors for Respirators a A Appendix A to Part 20 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Pt. 20.... External radiation hazards and other limitations to permitted exposure such as skin absorption shall be...

10 CFR Appendix A to Part 20 - Assigned Protection Factors for Respirators a

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Assigned Protection Factors for Respirators a A Appendix A to Part 20 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Pt. 20.... External radiation hazards and other limitations to permitted exposure such as skin absorption shall be...

10 CFR Appendix A to Part 20 - Assigned Protection Factors for Respirators a

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Assigned Protection Factors for Respirators a A Appendix A to Part 20 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Pt. 20.... External radiation hazards and other limitations to permitted exposure such as skin absorption shall be...

10 CFR Appendix A to Part 20 - Assigned Protection Factors for Respirators a

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Assigned Protection Factors for Respirators a A Appendix A to Part 20 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Pt. 20.... External radiation hazards and other limitations to permitted exposure such as skin absorption shall be...

Developing ICALL Tools Using GATE

ERIC Educational Resources Information Center

Wood, Peter

2008-01-01

This article discusses the use of the General Architecture for Text Engineering (GATE) as a tool for the development of ICALL and NLP applications. It outlines a paradigm shift in software development, which is mainly influenced by projects such as the Free Software Foundation. It looks at standards that have been proposed to facilitate the…

Derivation of a respiration trigger signal in small animal list-mode PET based on respiration-induced variations of the ECG signal.

PubMed

Todica, Andrei; Lehner, Sebastian; Wang, Hao; Zacherl, Mathias J; Nekolla, Katharina; Mille, Erik; Xiong, Guoming; Bartenstein, Peter; la Fougère, Christian; Hacker, Marcus; Böning, Guido

2016-02-01

Raw PET list-mode data contains motion artifacts causing image blurring and decreased spatial resolution. Unless corrected, this leads to underestimation of the tracer uptake and overestimation of the lesion size, as well as inaccuracies with regard to left ventricular volume and ejection fraction (LVEF), especially in small animal imaging. A respiratory trigger signal from respiration-induced variations in the electro-cardiogram (ECG) was detected. Original and revised list-mode PET data were used for calculation of left ventricular function parameters using both respiratory gating techniques. For adequately triggered datasets we saw no difference in mean respiratory cycle period between the reference standard (RRS) and the ECG-based (ERS) methods (1120 ± 159 ms vs 1120 ± 159 ms; P = n.s.). While the ECG-based method showed somewhat higher signal noise (66 ± 22 ms vs 51 ± 29 ms; P < .001), both respiratory triggering techniques yielded similar estimates for EDV, ESV, LVEF (RRS: 387 ± 56 µL, 162 ± 34 µL, 59 ± 5%; ERS: 389 ± 59 µL, 163 ± 35 µL, 59 ± 4%; P = n.s.). This study showed that respiratory gating signals can be accurately derived from cardiac trigger information alone, without the additional requirement for dedicated measurement of the respiratory motion in rats.

Implementing a Nitrogen-Based Model for Autotrophic Respiration Using Satellite and Field Observations

NASA Technical Reports Server (NTRS)

Choudhury, Bhaskar J.; Houser, Paul (Technical Monitor)

2001-01-01

The rate of carbon accumulation by terrestrial plant communities in a process-level, mechanistic modeling is the difference of the rate of gross photosynthesis by a canopy (A(sub g)) and autotrophic respiration (R) of the stand. Observations for different biomes often show that R to be a large and variable fraction of A(sub g), ca. 35% to 75%, although other studies suggest the ratio of R and A(sub g) to be less variable. Here, R has been calculated according to the two compartment model as being the sum of maintenance and growth components. The maintenance respiration of foliage and living fine roots for different biomes has been determined objectively from observed nitrogen content of these organs. The sapwood maintenance respiration is based on pipe theory, and checked against an independently derived equation considering sapwood biomass and its maintenance coefficient. The growth respiration has been calculated from the difference of A(sub g) and maintenance respiration. The A(sub g) is obtained as the product of biome-specific radiation use efficiency for gross photosynthesis under unstressed conditions and intercepted photosynthetically active radiation, and adjusted for stress. Calculations have been done using satellite and ground observations for 36 consecutive months (1987-1989) over large contiguous areas (ca. 10(exp 5) sq km) of boreal forests, crop land, temperate deciduous forest, temperate grassland, tropical deciduous forest, tropical evergreen forest, tropical savanna, and tundra. The ratio of annual respiration and gross photosynthesis, (R/A(sub g)), is found to be 0.5-0.6 for temperate and cold adopted biome areas, but somewhat higher for tropical biome areas (0.6-0.7). Interannual variation of the fluxes is found to be generally less than 15%. Calculated fluxes are compared with observations and several previous estimates. Results of sensitivity analysis are presented for uncertainties in parameterization and input data. It is found that

Organ radiation exposure with EOS: GATE simulations versus TLD measurements

NASA Astrophysics Data System (ADS)

Clavel, A. H.; Thevenard-Berger, P.; Verdun, F. R.; Létang, J. M.; Darbon, A.

2016-03-01

EOS® is an innovative X-ray imaging system allowing the acquisition of two simultaneous images of a patient in the standing position, during the vertical scan of two orthogonal fan beams. This study aimed to compute organs radiation exposure to a patient, in the particular geometry of this system. Two different positions of the patient in the machine were studied, corresponding to postero-anterior plus left lateral projections (PA-LLAT) and antero-posterior plus right lateral projections (AP-RLAT). To achieve this goal, a Monte-Carlo simulation was developed based on a GATE environment. To model the physical properties of the patient, a computational phantom was produced based on computed tomography scan data of an anthropomorphic phantom. The simulations provided several organs doses, which were compared to previously published dose results measured with Thermo Luminescent Detectors (TLD) in the same conditions and with the same phantom. The simulation results showed a good agreement with measured doses at the TLD locations, for both AP-RLAT and PA-LLAT projections. This study also showed that the organ dose assessed only from a sample of locations, rather than considering the whole organ, introduced significant bias, depending on organs and projections.

Dual-Gated Motion-Frozen Cardiac PET with Flurpiridaz F 18.

PubMed

Slomka, Piotr J; Rubeaux, Mathieu; Le Meunier, Ludovic; Dey, Damini; Lazewatsky, Joel L; Pan, Tinsu; Dweck, Marc R; Newby, David E; Germano, Guido; Berman, Daniel S

2015-12-01

A novel PET radiotracer, Flurpiridaz F 18, has undergone phase II clinical trial evaluation as a high-resolution PET cardiac perfusion imaging agent. In a subgroup of patients imaged with this agent, we assessed the feasibility and benefit of simultaneous correction of respiratory and cardiac motion. In 16 patients, PET imaging was performed on a 4-ring scanner in dual cardiac and respiratory gating mode. Four sets of data were reconstructed with high-definition reconstruction (HD•PET): ungated and 8-bin electrocardiography-gated images using 5-min acquisition, optimal respiratory gating (ORG)-as developed for oncologic imaging-using a narrow range of breathing amplitude around end-expiration level with 35% of the counts in a 7-min acquisition, and 4-bin respiration-gated and 8-bin electrocardiography-gated images (32 bins in total) using the 7-min acquisition (dual-gating, using all data). Motion-frozen (MF) registration algorithms were applied to electrocardiography-gated and dual-gated data, creating cardiac-MF and dual-MF images. We computed wall thickness, wall/cavity contrast, and contrast-to-noise ratio for standard, ORG, cardiac-MF, and dual-MF images to assess image quality. The wall/cavity contrast was similar for ungated (9.3 ± 2.9) and ORG (9.5 ± 3.2) images and improved for cardiac-MF (10.8 ± 3.6) and dual-MF images (14.8 ± 8.0) (P < 0.05). The contrast-to-noise ratio was 22.2 ± 9.1 with ungated, 24.7 ± 12.2 with ORG, 35.5 ± 12.8 with cardiac-MF, and 42.1 ± 13.2 with dual-MF images (all P < 0.05). The wall thickness was significantly decreased (P < 0.05) with dual-MF (11.6 ± 1.9 mm) compared with ungated (13.9 ± 2.8 mm), ORG (13.1 ± 2.9 mm), and cardiac-MF images (12.1 ± 2.7 mm). Dual (respiratory/cardiac)-gated perfusion imaging with Flurpiridaz F 18 is feasible and improves image resolution, contrast, and contrast-to-noise ratio when MF registration methods are applied. © 2015 by the Society of Nuclear Medicine and Molecular Imaging

Radiation-induced cardiovascular effects

NASA Astrophysics Data System (ADS)

Tapio, Soile

Recent epidemiological studies indicate that exposure to ionising radiation enhances the risk of cardiovascular mortality and morbidity in a moderate but significant manner. Our goal is to identify molecular mechanisms involved in the pathogenesis of radiation-induced cardiovascular disease using cellular and mouse models. Two radiation targets are studied in detail: the vascular endothelium that plays a pivotal role in the regulation of cardiac function, and the myocardium, in particular damage to the cardiac mitochondria. Ionising radiation causes immediate and persistent alterations in several biological pathways in the endothelium in a dose- and dose-rate dependent manner. High acute and cumulative doses result in rapid, non-transient remodelling of the endothelial cytoskeleton, as well as increased lipid peroxidation and protein oxidation of the heart tissue, independent of whether exposure is local or total body. Proteomic and functional changes are observed in lipid metabolism, glycolysis, mitochondrial function (respiration, ROS production etc.), oxidative stress, cellular adhesion, and cellular structure. The transcriptional regulators Akt and PPAR alpha seem to play a central role in the radiation-response of the endothelium and myocardium, respectively. We have recently started co-operation with GSI in Darmstadt to study the effect of heavy ions on the endothelium. Our research will facilitate the identification of biomarkers associated with adverse cardiac effects of ionising radiation and may lead to the development of countermeasures against radiation-induced cardiac damage.

Integrating respiratory gating into a megavoltage cone-beam CT system

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

Chang Jenghwa; Sillanpaa, Jussi; Ling, Clifton C.

2006-07-15

We have previously described a low-dose megavoltage cone beam computed tomography (MV CBCT) system capable of producing projection image using one beam pulse. In this study, we report on its integration with respiratory gating for gated radiotherapy. The respiratory gating system tracks a reflective marker on the patient's abdomen midway between the xiphoid and umbilicus, and disables radiation delivery when the marker position is outside predefined thresholds. We investigate two strategies for acquiring gated scans. In the continuous rotation-gated acquisition, the linear accelerator (LINAC) is set to the fixed x-ray mode and the gantry makes a 5 min, 360 deg.continuousmore » rotation, during which the gating system turns the radiation beam on and off, resulting in projection images with an uneven distribution of projection angles (e.g., in 70 arcs each covering 2 deg.). In the gated rotation-continuous acquisition, the LINAC is set to the dynamic arc mode, which suspends the gantry rotation when the gating system inhibits the beam, leading to a slightly longer (6-7 min) scan time, but yielding projection images with more evenly distributed projection angles (e.g., {approx}0.8 deg.between two consecutive projection angles). We have tested both data acquisition schemes on stationary (a contrast detail and a thoracic) phantoms and protocol lung patients. For stationary phantoms, a separate motion phantom not visible in the images is used to trigger the RPM system. Frame rate is adjusted so that approximately 450 images (13 MU) are acquired for each scan and three-dimensional tomographic images reconstructed using a Feldkamp filtered backprojection algorithm. The gated rotation-continuous acquisition yield reconstructions free of breathing artifacts. The tumor in parenchymal lung and normal tissues are easily discernible and the boundary between the diaphragm and the lung sharply defined. Contrast-to-noise ratio (CNR) is not degraded relative to nongated scans of

Plastron Respiration Using Commercial Fabrics

PubMed Central

Atherton, Shaun; Brennan, Joseph C.; Morris, Robert H.; Smith, Joshua D.E.; Hamlett, Christopher A.E.; McHale, Glen; Shirtcliffe, Neil J.; Newton, Michael I.

2014-01-01

A variety of insect and arachnid species are able to remain submerged in water indefinitely using plastron respiration. A plastron is a surface-retained film of air produced by surface morphology that acts as an oxygen-carbon dioxide exchange surface. Many highly water repellent and hydrophobic surfaces when placed in water exhibit a silvery sheen which is characteristic of a plastron. In this article, the hydrophobicity of a range of commercially available water repellent fabrics and polymer membranes is investigated, and how the surface of the materials mimics this mechanism of underwater respiration is demonstrated allowing direct extraction of oxygen from oxygenated water. The coverage of the surface with the plastron air layer was measured using confocal microscopy. A zinc/oxygen cell is used to consume oxygen within containers constructed from the different membranes, and the oxygen consumed by the cell is compared to the change in oxygen concentration as measured by an oxygen probe. By comparing the membranes to an air-tight reference sample, it was found that the membranes facilitated oxygen transfer from the water into the container, with the most successful membrane showing a 1.90:1 ratio between the cell oxygen consumption and the change in concentration within the container. PMID:28788469

[Comparison of radiation dose reduction of prospective ECG-gated one beat scan using 320 area detector CT coronary angiography and prospective ECG-gated helical scan with high helical pitch (FlashScan) using 64 multidetector-row CT coronary angiography].

PubMed

Matsutani, Hideyuki; Sano, Tomonari; Kondo, Takeshi; Fujimoto, Shinichiro; Sekine, Takako; Arai, Takehiro; Morita, Hitomi; Takase, Shinichi

2010-12-20

A high radiation dose associated with 64 multidetector-row computed tomography (64-MDCT) is a major concern for physicians and patients alike. A new 320 row area detector computed tomography (ADCT) can obtain a view of the entire heart with one rotation (0.35 s) without requiring the helical method. As such, ADCT is expected to reduce the radiation dose. We studied image quality and radiation dose of ADCT compared to that of 64-MDCT in patients with a low heart rate (HR≤60). Three hundred eighty-five consecutive patients underwent 64-MDCT and 379 patients, ADCT. Patients with an arrhythmia were excluded. Prospective ECG-gated helical scan with high HP (FlashScan) in 64 was used for MDCT and prospective ECG-gated conventional one beat scan, for 320-ADCT. Image quality was visually evaluated by an image quality score. Radiation dose was estimated by DLP (mGy･cm) for 64-MDCT and DLP.e (mGy･cm) for 320-ADCT. Radiation dose of 320-ADCT (208±48 mGy･cm) was significantly (P<0.0001) lower than that of 64-MDCT (484±112 mGy･cm), and image quality score of 320-ADCT (3.0±0.2) was significantly (P=0.0011) higher than that of 64-MDCT (2.9±0.4). Scan time of 320-ADCT (1.4±0.1 s) was also significantly (P<0.0001) shorter than that of 64-MDCT (6.8±0.6 s). 320-ADCT can achieve not only a reduction in radiation dose but also a superior image quality and shortening of scan time compared to 64-MDCT.

Nosepiece respiration monitor

NASA Technical Reports Server (NTRS)

Lavery, A. L.; Long, L. E.; Rice, N. E.

1968-01-01

Comfortable, inexpensive nosepiece respiration monitor produces rapid response signals to most conventional high impedance medical signal conditioners. The monitor measures respiration in a manner that produces a large signal with minimum delay.

Respiratory-gated segment reconstruction for radiation treatment planning using 256-slice CT-scanner during free breathing

NASA Astrophysics Data System (ADS)

Mori, Shinichiro; Endo, Masahiro; Kohno, Ryosuke; Minohara, Shinichi; Kohno, Kazutoshi; Asakura, Hiroshi; Fujiwara, Hideaki; Murase, Kenya

2005-04-01

The conventional respiratory-gated CT scan technique includes anatomic motion induced artifacts due to the low temporal resolution. They are a significant source of error in radiotherapy treatment planning for the thorax and upper abdomen. Temporal resolution and image quality are important factors to minimize planning target volume margin due to the respiratory motion. To achieve high temporal resolution and high signal-to-noise ratio, we developed a respiratory gated segment reconstruction algorithm and adapted it to Feldkamp-Davis-Kress algorithm (FDK) with a 256-detector row CT. The 256-detector row CT could scan approximately 100 mm in the cranio-caudal direction with 0.5 mm slice thickness in one rotation. Data acquisition for the RS-FDK relies on the assistance of the respiratory sensing system by a cine scan mode (table remains stationary). We evaluated RS-FDK in phantom study with the 256-detector row CT and compared it with full scan (FS-FDK) and HS-FDK results with regard to volume accuracy and image noise, and finally adapted the RS-FDK to an animal study. The RS-FDK gave a more accurate volume than the others and it had the same signal-to-noise ratio as the FS-FDK. In the animal study, the RS-FDK visualized the clearest edges of the liver and pulmonary vessels of all the algorithms. In conclusion, the RS-FDK algorithm has a capability of high temporal resolution and high signal-to-noise ratio. Therefore it will be useful when combined with new radiotherapy techniques including image guided radiation therapy (IGRT) and 4D radiation therapy.

Net photosynthesis and respiration of sago pondweed (Potamogeton pectinatus) exposed to herbicides

USGS Publications Warehouse

Fleming, W.J.; Ailstock, M.S.; Momot, J.J.; Hughes, Jane S.; Biddinger, Gregory R.; Mones, Eugene

1995-01-01

We determined net photosynthesis and respiration rates for sago pondweed (potamogeton pectinatus) exposed to various concentrations of 11 herbicides widely used in Maryland during the past decade. Net photosynthesis and respiration were determined by measuring changes in the. oxygen content of solutions containing dilutions of technical grade herbicides. At 20-22? C and 58 umol/m2/sec of photosynthetically active radiation (PAR), oxygen production of undosed plants averaged 0.72-2.03 mg/g fresh wt/h. Respiration rates of undosed plants averaged 0.46-0.60 mg O2/g fresh wt/h. Nominal herbicide concentrations (ng/L) that reduced net photosynthesis by 5O percent (IC5O) were: metribuzin, 8; atrazine, 29; cyanazine, 32; linuron, 70; simazine, 164; and paraquat, 240. IC5O values for 2,4-D, acifluorfen, glyphosate and metolachlor exceeded the maximum test concentration of 10,000 ng/L. The IC5O value for alachlor was estimated to be between 1,000 and 10,000 ng/L. None of the herbicides tested had a significant effect on dark respiration.

Respirator Fact Sheet

MedlinePlus

... the respirator. If I have the right cartridges/filters for a certain hazard, and my mask fits, ... use and maintenance are essential. Will my cartridge/filter and respirator mask protect forever? Cartridges, filters, and ...

In vivo measurements of structure/electrode position changes during respiration for Electrical Impedance Tomography

NASA Astrophysics Data System (ADS)

Zhang, Jie; Qin, Lihong; Allen, Tadashi; Patterson, Robert

2010-04-01

For pulmonary applications of EIT systems, the electrodes are placed around the chest in a 2D ring, and the images are reconstructed based on the assumptions that the object is rigid and the measured resistivity change in EIT images is only caused by the actual resistivity change of tissue. Structural changes are rarely considered. Previous studies have shown that structural changes which result in tissue/organ and electrode position change tend to introduce artifacts to EIT images of the thorax. Since EIT reconstruction is an ill-posed inverse problem, any inaccurate assumptions of object may cause large artifacts in reconstructed images. Accurate information on structure/electrode position changes is necessary to understand factors contributing to the measured resistivity changes and to improve EIT reconstruction algorithm. In this study, in vivo structure/electrode position changes from a healthy male volunteer are investigated during respiration cycle at two levels, the nipple line level and the level approximately 5 cm below. For each level, sixteen fiduciary markers are equally spaced around the surface, the same as the electrode placement for EIT measurements. A MR scanner with respiration-gated ability is used to acquire images of the thorax. MR thoracic images are prospectively acquired corresponding temporally to specific time periods within respiration cycle (FRC, mid tidal volume, tidal volume). The chest expansions in anterior-posterior and lateral directions and inside tissue/organ position changes are then analyzed. The electrode position changes corresponding to different phases of respiration cycle are also measured.

Reverse-engineering flow-cytometry gating strategies for phenotypic labelling and high-performance cell sorting.

PubMed

Becht, Etienne; Simoni, Yannick; Coustan-Smith, Elaine; Maximilien, Evrard; Cheng, Yang; Ng, Lai Guan; Campana, Dario; Newell, Evan

2018-06-21

Recent flow and mass cytometers generate datasets of dimensions 20 to 40 and a million single cells. From these, many tools facilitate the discovery of new cell populations associated with diseases or physiology. These new cell populations require the identification of new gating strategies, but gating strategies become exponentially more difficult to optimize when dimensionality increases. To facilitate this step, we developed Hypergate, an algorithm which given a cell population of interest identifies a gating strategy optimized for high yield and purity. Hypergate achieves higher yield and purity than human experts, Support Vector Machines and Random-Forests on public datasets. We use it to revisit some established gating strategies for the identification of innate lymphoid cells, which identifies concise and efficient strategies that allow gating these cells with fewer parameters but higher yield and purity than the current standards. For phenotypic description, Hypergate's outputs are consistent with fields' knowledge and sparser than those from a competing method. Hypergate is implemented in R and available on CRAN. The source code is published at http://github.com/ebecht/hypergate under an Open Source Initiative-compliant licence. Supplementary data are available at Bioinformatics online.

49 CFR 234.255 - Gate arm and gate mechanism.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be...

49 CFR 234.255 - Gate arm and gate mechanism.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be...

49 CFR 234.255 - Gate arm and gate mechanism.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month. (c...

49 CFR 234.255 - Gate arm and gate mechanism.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month. (c...

49 CFR 234.255 - Gate arm and gate mechanism.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Gate arm and gate mechanism. 234.255 Section 234....255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be observed for proper operation at least once each month. (c...

Soil Respiration And Respiration Partitioning In An Oak-Savannah With A History Of Fertilization

NASA Astrophysics Data System (ADS)

Morris, K. A.; Nair, R.; Schrumpf, M.; Migliavacca, M.

2017-12-01

Soil respiration is a combination of autotrophic and heterotrophic components. These components have different controls and structurally complex ecosystems such as oak-savannahs offer an opportunity to study strongly contrasting conditions (ie., soil from under trees versus open areas) in an environment with similar soil mineralogy and climatic patterns. To measure respiration coming from plant roots, fungal hyphae, and free-living microbes we established stations of soil cores comprised of three selectively permeable meshes under tree canopies and in open grassy areas of a Holm Oak (Quercus ilex) savannah in Extremadura, Spain. Large plots of this ecosystem had previously been fertilized as part of a stoichiometeric imbalance study (in 2015). Stations were installed in Dec. 2016 within four plots; control, N added, P added, and N+P added. Respiration from cores was measured in campaigns at key phenological stages with a portable Li-Cor 8100A unit. Six months after installation > 50% of soil respiration was attributable to free-living microbes. There is a persistent effect of the prior fertilization, resulting in increased soil respiration in open areas regardless of fertilizer type, while respiration from under tree canopies had a varied response. Soil under tree canopies showed distinct sensitivity to stoichiometric imbalance, meaning that addition of N or P alone either did not change respiration or decreased it slightly, while N+P stimulated respiration. We determined that respiration from free-living microbes is a major component of soil respiration even in the most active plant growing season. However, because of the lag between the time of fertilization and the time of measurement, it not possible to say whether treatment responses are due solely to nutrient status of the soil or whether changes in plant biomass and species composition also play a role. Additional work planned at the site will shed light on this uncertainty as well as the contribution of

Comparison between beta radiation dose distribution due to LDR and HDR ocular brachytherapy applicators using GATE Monte Carlo platform.

PubMed

Mostafa, Laoues; Rachid, Khelifi; Ahmed, Sidi Moussa

2016-08-01

Eye applicators with 90Sr/90Y and 106Ru/106Rh beta-ray sources are generally used in brachytherapy for the treatment of eye diseases as uveal melanoma. Whenever, radiation is used in treatment, dosimetry is essential. However, knowledge of the exact dose distribution is a critical decision-making to the outcome of the treatment. The Monte Carlo technique provides a powerful tool for calculation of the dose and dose distributions which helps to predict and determine the doses from different shapes of various types of eye applicators more accurately. The aim of this work consisted in using the Monte Carlo GATE platform to calculate the 3D dose distribution on a mathematical model of the human eye according to international recommendations. Mathematical models were developed for four ophthalmic applicators, two HDR 90Sr applicators SIA.20 and SIA.6, and two LDR 106Ru applicators, a concave CCB model and a flat CCB model. In present work, considering a heterogeneous eye phantom and the chosen tumor, obtained results with the use of GATE for mean doses distributions in a phantom and according to international recommendations show a discrepancy with respect to those specified by the manufacturers. The QC of dosimetric parameters shows that contrarily to the other applicators, the SIA.20 applicator is consistent with recommendations. The GATE platform show that the SIA.20 applicator present better results, namely the dose delivered to critical structures were lower compared to those obtained for the other applicators, and the SIA.6 applicator, simulated with MCNPX generates higher lens doses than those generated by GATE. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Disruption of the IS6-AID linker affects voltage-gated calcium channel inactivation and facilitation.

PubMed

Findeisen, Felix; Minor, Daniel L

2009-03-01

Two processes dominate voltage-gated calcium channel (Ca(V)) inactivation: voltage-dependent inactivation (VDI) and calcium-dependent inactivation (CDI). The Ca(V)beta/Ca(V)alpha(1)-I-II loop and Ca(2+)/calmodulin (CaM)/Ca(V)alpha(1)-C-terminal tail complexes have been shown to modulate each, respectively. Nevertheless, how each complex couples to the pore and whether each affects inactivation independently have remained unresolved. Here, we demonstrate that the IS6-alpha-interaction domain (AID) linker provides a rigid connection between the pore and Ca(V)beta/I-II loop complex by showing that IS6-AID linker polyglycine mutations accelerate Ca(V)1.2 (L-type) and Ca(V)2.1 (P/Q-type) VDI. Remarkably, mutations that either break the rigid IS6-AID linker connection or disrupt Ca(V)beta/I-II association sharply decelerate CDI and reduce a second Ca(2+)/CaM/Ca(V)alpha(1)-C-terminal-mediated process known as calcium-dependent facilitation. Collectively, the data strongly suggest that components traditionally associated solely with VDI, Ca(V)beta and the IS6-AID linker, are essential for calcium-dependent modulation, and that both Ca(V)beta-dependent and CaM-dependent components couple to the pore by a common mechanism requiring Ca(V)beta and an intact IS6-AID linker.

Disruption of the IS6-AID Linker Affects Voltage-gated Calcium Channel Inactivation and Facilitation

PubMed Central

Findeisen, Felix

2009-01-01

Two processes dominate voltage-gated calcium channel (CaV) inactivation: voltage-dependent inactivation (VDI) and calcium-dependent inactivation (CDI). The CaVβ/CaVα1-I-II loop and Ca2+/calmodulin (CaM)/CaVα1–C-terminal tail complexes have been shown to modulate each, respectively. Nevertheless, how each complex couples to the pore and whether each affects inactivation independently have remained unresolved. Here, we demonstrate that the IS6–α-interaction domain (AID) linker provides a rigid connection between the pore and CaVβ/I-II loop complex by showing that IS6-AID linker polyglycine mutations accelerate CaV1.2 (L-type) and CaV2.1 (P/Q-type) VDI. Remarkably, mutations that either break the rigid IS6-AID linker connection or disrupt CaVβ/I-II association sharply decelerate CDI and reduce a second Ca2+/CaM/CaVα1–C-terminal–mediated process known as calcium-dependent facilitation. Collectively, the data strongly suggest that components traditionally associated solely with VDI, CaVβ and the IS6-AID linker, are essential for calcium-dependent modulation, and that both CaVβ-dependent and CaM-dependent components couple to the pore by a common mechanism requiring CaVβ and an intact IS6-AID linker. PMID:19237593

Analogy-Integrated e-Learning Module: Facilitating Students' Conceptual Understanding

ERIC Educational Resources Information Center

Florida, Jennifer

2012-01-01

The study deals with the development of an analogy-integrated e-learning module on Cellular Respiration, which is intended to facilitate conceptual understanding of students with different brain hemisphere dominance and learning styles. The module includes eight analogies originally conceptualized following the specific steps used to prepare…

Gating of proton and water transfer in the respiratory enzyme cytochrome c oxidase.

PubMed

Wikström, Mårten; Ribacka, Camilla; Molin, Mika; Laakkonen, Liisa; Verkhovsky, Michael; Puustinen, Anne

2005-07-26

The membrane-bound enzyme cytochrome c oxidase is responsible for cell respiration in aerobic organisms and conserves free energy from O2 reduction into an electrochemical proton gradient by coupling the redox reaction to proton-pumping across the membrane. O2 reduction produces water at the bimetallic heme a3/CuB active site next to a hydrophobic cavity deep within the membrane. Water molecules in this cavity have been suggested to play an important role in the proton-pumping mechanism. Here, we show by molecular dynamics simulations that the conserved arginine/heme a3 delta-propionate ion pair provides a gate, which exhibits reversible thermal opening that is governed by the redox state and the water molecules in the cavity. An important role of this gate in the proton-pumping mechanism is supported by site-directed mutagenesis experiments. Transport of the product water out of the enzyme must be rigidly controlled to prevent water-mediated proton leaks that could compromise the proton-pumping function. Exit of product water is observed through the same arginine/propionate gate, which provides an explanation for the observed extraordinary spatial specificity of water expulsion from the enzyme.

Direct detector for terahertz radiation

DOEpatents

Wanke, Michael C [Albuquerque, NM; Lee, Mark [Albuquerque, NM; Shaner, Eric A [Albuquerque, NM; Allen, S James [Santa Barbara, CA

2008-09-02

A direct detector for terahertz radiation comprises a grating-gated field-effect transistor with one or more quantum wells that provide a two-dimensional electron gas in the channel region. The grating gate can be a split-grating gate having at least one finger that can be individually biased. Biasing an individual finger of the split-grating gate to near pinch-off greatly increases the detector's resonant response magnitude over prior QW FET detectors while maintaining frequency selectivity. The split-grating-gated QW FET shows a tunable resonant plasmon response to FIR radiation that makes possible an electrically sweepable spectrometer-on-a-chip with no moving mechanical optical parts. Further, the narrow spectral response and signal-to-noise are adequate for use of the split-grating-gated QW FET in a passive, multispectral terahertz imaging system. The detector can be operated in a photoconductive or a photovoltaic mode. Other embodiments include uniform front and back gates to independently vary the carrier densities in the channel region, a thinned substrate to increase bolometric responsivity, and a resistive shunt to connect the fingers of the grating gate in parallel and provide a uniform gate-channel voltage along the length of the channel to increase the responsivity and improve the spectral resolution.

Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

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

Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan

2013-03-01

Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matchingmore » algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties.« less

A study on quantitative analysis of field size and dose by using gating system in 4D conformal radiation treatment

NASA Astrophysics Data System (ADS)

Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Chung, Woon-Kwan; Cho, Jae-Hwan; Lee, Hae-Kag

2012-10-01

This study evaluated the gating-based 4-D conformal radiation therapy (4D-CT) treatment planning by a comparison with the common 3-D conformal radiation therapy (3D-CT) treatment planning and examined the change in treatment field size and dose to the tumors and adjacent normal tissues because an unnecessary dose is also included in the 3-D treatment planning for the radiation treatment of tumors in the chest and abdomen. The 3D-CT and gating-based 4D-CT images were obtained from patients who had undergone radiation treatment for chest and abdomen tumors in the oncology department. After establishing a treatment plan, the CT treatment and planning system were used to measure the change in field size for analysis. A dose volume histogram (DVH) was used to calculate the appropriate dose to planning target volume (PTV) tumors and adjacent normal tissue. The difference in the treatment volume of the chest was 0.6 and 0.83 cm on the X- and Y-axis, respectively, for the gross tumor volume (GTV). Accordingly, the values in the 4D-CT treatment planning were smaller and the dose was more concentrated by 2.7% and 0.9% on the GTV and clinical target volume (CTV), respectively. The normal tissues in the surrounding normal tissues were reduced by 3.0%, 7.2%, 0.4%, 1.7%, 2.6% and 0.2% in the bronchus, chest wall, esophagus, heart, lung and spinal cord, respectively. The difference in the treatment volume of the abdomen was 0.72 cm on the X-axis and 0.51 cm on the Y-axis for the GTV; and 1.06 cm on the X-axis and 1.85 cm on the Y-axis for the PTV. Therefore, the values in the 4D-CT treatment planning were smaller. The dose was concentrated by 6.8% and 4.3% on the GTV and PTV, respectively, whereas the adjacent normal tissues in the cord, Lt. kidney, Rt. kidney, small bowels and whole liver were reduced by 3.2%, 4.2%, 1.5%, 6.2% and 12.7%, respectively. The treatment field size was smaller in volume in the case of the 4D-CT treatment planning. In the DVH, the 4D-CT treatment

REGULATORY MECHANISMS OF CELLULAR RESPIRATION

PubMed Central

Barron, E. S. Guzman; Nelson, Leonard; Ardao, Maria Isabel

1948-01-01

Oxidizing agents of sulfhydryl groups such as iodosobenzoate, alkylating agents such as iodoacetamide, and mercaptide-forming agents such as cadmium chloride, mercuric chloride, p-chloromercuribenzoate, sodium arsenite, and p-carboxyphenylarsine oxide, added in small concentrations to a suspension of sea urchin sperm produced an increase in respiration. When the concentration was increased there was an inhibition. These effects are explained by postulating the presence in the cells of two kinds of sulfhydryl groups: soluble sulfhydryl groups, which regulate cellular respiration, and fixed sulfhydryl groups, present in the protein moiety of enzymes. Small concentrations of sulfhydryl reagents combine only with the first, thus producing an increase in respiration; when the concentration is increased, the fixed sulfhydryl groups are also attacked and inhibition of respiration is the consequence. Other inhibitors of cell respiration, such as cyanide and urethanes, which do not combine with —SH groups, did not stimulate respiration in small concentration. PMID:18891144

Evaluation of tumor localization in respiration motion-corrected cone-beam CT: Prospective study in lung

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

Dzyubak, Oleksandr; Kincaid, Russell; Hertanto, Agung

Purpose: Target localization accuracy of cone-beam CT (CBCT) images used in radiation treatment of respiratory disease sites is affected by motion artifacts (blurring and streaking). The authors have previously reported on a method of respiratory motion correction in thoracic CBCT at end expiration (EE). The previous retrospective study was limited to examination of reducing motion artifacts in a small number of patient cases. They report here on a prospective study in a larger group of lung cancer patients to evaluate respiratory motion-corrected (RMC)-CBCT ability to improve lung tumor localization accuracy and reduce motion artifacts in Linac-mounted CBCT images. A secondmore » study goal examines whether the motion correction derived from a respiration-correlated CT (RCCT) at simulation yields similar tumor localization accuracy at treatment. Methods: In an IRB-approved study, 19 lung cancer patients (22 tumors) received a RCCT at simulation, and on one treatment day received a RCCT, a respiratory-gated CBCT at end expiration, and a 1-min CBCT. A respiration monitor of abdominal displacement was used during all scans. In addition to a CBCT reconstruction without motion correction, the motion correction method was applied to the same 1-min scan. Projection images were sorted into ten bins based on abdominal displacement, and each bin was reconstructed to produce ten intermediate CBCT images. Each intermediate CBCT was deformed to the end expiration state using a motion model derived from RCCT. The deformed intermediate CBCT images were then added to produce a final RMC-CBCT. In order to evaluate the second study goal, the CBCT was corrected in two ways, one using a model derived from the RCCT at simulation [RMC-CBCT(sim)], the other from the RCCT at treatment [RMC-CBCT(tx)]. Image evaluation compared uncorrected CBCT, RMC-CBCT(sim), and RMC-CBCT(tx). The gated CBCT at end expiration served as the criterion standard for comparison. Using automatic rigid image

Evaluation of tumor localization in respiration motion-corrected cone-beam CT: prospective study in lung.

PubMed

Dzyubak, Oleksandr; Kincaid, Russell; Hertanto, Agung; Hu, Yu-Chi; Pham, Hai; Rimner, Andreas; Yorke, Ellen; Zhang, Qinghui; Mageras, Gig S

2014-10-01

Target localization accuracy of cone-beam CT (CBCT) images used in radiation treatment of respiratory disease sites is affected by motion artifacts (blurring and streaking). The authors have previously reported on a method of respiratory motion correction in thoracic CBCT at end expiration (EE). The previous retrospective study was limited to examination of reducing motion artifacts in a small number of patient cases. They report here on a prospective study in a larger group of lung cancer patients to evaluate respiratory motion-corrected (RMC)-CBCT ability to improve lung tumor localization accuracy and reduce motion artifacts in Linac-mounted CBCT images. A second study goal examines whether the motion correction derived from a respiration-correlated CT (RCCT) at simulation yields similar tumor localization accuracy at treatment. In an IRB-approved study, 19 lung cancer patients (22 tumors) received a RCCT at simulation, and on one treatment day received a RCCT, a respiratory-gated CBCT at end expiration, and a 1-min CBCT. A respiration monitor of abdominal displacement was used during all scans. In addition to a CBCT reconstruction without motion correction, the motion correction method was applied to the same 1-min scan. Projection images were sorted into ten bins based on abdominal displacement, and each bin was reconstructed to produce ten intermediate CBCT images. Each intermediate CBCT was deformed to the end expiration state using a motion model derived from RCCT. The deformed intermediate CBCT images were then added to produce a final RMC-CBCT. In order to evaluate the second study goal, the CBCT was corrected in two ways, one using a model derived from the RCCT at simulation [RMC-CBCT(sim)], the other from the RCCT at treatment [RMC-CBCT(tx)]. Image evaluation compared uncorrected CBCT, RMC-CBCT(sim), and RMC-CBCT(tx). The gated CBCT at end expiration served as the criterion standard for comparison. Using automatic rigid image registration, each CBCT was

Interpreting, measuring, and modeling soil respiration

Treesearch

Michael G. Ryan; Beverly E. Law

2005-01-01

This paper reviews the role of soil respiration in determining ecosystem carbon balance, and the conceptual basis for measuring and modeling soil respiration. We developed it to provide background and context for this special issue on soil respiration and to synthesize the presentations and discussions at the workshop. Soil respiration is the largest component of...

SU-G-JeP3-14: Positioning and Dosimetric Uncertainties in Image-Guided Radiation Therapy with Respiratory Gating

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

Ali, I; Hossain, S; Algan, O

Purpose: To investigate quantitatively positioning and dosimetric uncertainties due to 4D-CT intra-phase motion in the internal-target-volume (ITV) associated with radiation therapy using respiratory-gating for patients setup with image-guidance-radiation-therapy (IGRT) using free-breathing or average-phase CT-images. Methods: A lung phantom with an embedded tissue-equivalent target is imaged with CT while it is stationary and moving. Four-sets of structures are outlined: (a) the actual target on CT-images of the stationary-target, (b) ITV on CT-images for the free-moving phantom, (c) ITV’s from the ten different phases (10–100%) and (d) ITV on the CT-images generated from combining 3 phases: 40%–50%–60%. The variations in volume, lengthmore » and center-position of the ITV’s and their effects on dosimetry during dose delivery for patients setup with image-guidance are investigated. Results: Intra-phase motion due to breathing affects the volume, center position and length of the ITVs from different respiratory-phases. The ITV’s vary by about 10% from one phase to another. The largest ITV is measured on the free breathing CT images and the smallest is on the stationary CT-images. The ITV lengths vary by about 4mm where it may shrink or elongated depending on the motion-phase. The center position of the ITV varies between the different motion-phases which shifts upto 10mm from the stationary-position which is nearly equal to motion-amplitude. This causes systematic shifts during dose delivery with beam gating using certain phases (40%–50%–60%) for patients setup with IGRT using free-breathing or average-phase CT-images. The dose coverage of the ITV depends on the margins used for treatment-planning-volume where margins larger than the motion-amplitudes are needed to ensure dose coverage of the ITV. Conclusion: Volume, length, and center position of the ITV’s change between the different motion phases. Large systematic shifts are induced by

Integration of SimSET photon history generator in GATE for efficient Monte Carlo simulations of pinhole SPECT.

PubMed

Chen, Chia-Lin; Wang, Yuchuan; Lee, Jason J S; Tsui, Benjamin M W

2008-07-01

The authors developed and validated an efficient Monte Carlo simulation (MCS) workflow to facilitate small animal pinhole SPECT imaging research. This workflow seamlessly integrates two existing MCS tools: simulation system for emission tomography (SimSET) and GEANT4 application for emission tomography (GATE). Specifically, we retained the strength of GATE in describing complex collimator/detector configurations to meet the anticipated needs for studying advanced pinhole collimation (e.g., multipinhole) geometry, while inserting the fast SimSET photon history generator (PHG) to circumvent the relatively slow GEANT4 MCS code used by GATE in simulating photon interactions inside voxelized phantoms. For validation, data generated from this new SimSET-GATE workflow were compared with those from GATE-only simulations as well as experimental measurements obtained using a commercial small animal pinhole SPECT system. Our results showed excellent agreement (e.g., in system point response functions and energy spectra) between SimSET-GATE and GATE-only simulations, and, more importantly, a significant computational speedup (up to approximately 10-fold) provided by the new workflow. Satisfactory agreement between MCS results and experimental data were also observed. In conclusion, the authors have successfully integrated SimSET photon history generator in GATE for fast and realistic pinhole SPECT simulations, which can facilitate research in, for example, the development and application of quantitative pinhole and multipinhole SPECT for small animal imaging. This integrated simulation tool can also be adapted for studying other preclinical and clinical SPECT techniques.

Diurnal Patterns of Heterotrophic and Autotrophic Soil Respiration in Maize and Switchgrass Bioenergy Cropping Systems

NASA Astrophysics Data System (ADS)

von Haden, A.; Marin-Spiotta, E.; Jackson, R. D.; Kucharik, C. J.

2016-12-01

A high proportion of carbon lost from terrestrial ecosystems occurs via soil CO2 respiration. Soil respiration is comprised of two contrasting sources: heterotrophic respiration (RH) from the decomposition of organic matter and autotrophic respiration (RA) from plant root metabolism. Since the two sources of soil respiration vary widely in their origin, the controls of each source are also likely to differ. However, the challenge of partitioning soil respiration sources in situ has limited our mechanistic understanding of RH and RA. Our objective was to evaluate the in situ diurnal controls of RH and RA in maize (Zea mays L.) and switchgrass (Panicum virgatum L.) bioenergy cropping systems. We hypothesized that both RH and RA would follow diurnal soil temperature trends, but that RA would also respond to diel patterns of photosynthetically active radiation (PAR). We also expected that diurnal soil respiration patterns would vary significantly within the growing season. We evaluated our hypothesis with six diurnal soil respiration campaigns during the 2015 and 2016 growing seasons at Arlington, WI, USA. RH showed clear oscillating diel trends, typically peaking in the mid-afternoon when near-surface soil temperatures were highest. Diurnal RA patterns were more nuanced than RH, but were generally highest in the late afternoon and showed the most pronounced diel trends during peak growing season in July. RA also tended to spike in concert with PAR, but this effect was much more prominent in maize than switchgrass. Continuing efforts will attempt to quantitatively separate the effects of soil temperature and PAR on RA.

A chimeric prokaryotic pentameric ligand–gated channel reveals distinct pathways of activation

DOE PAGES

Schmandt, Nicolaus; Velisetty, Phanindra; Chalamalasetti, Sreevatsa V.; ...

2015-09-28

Recent high resolution structures of several pentameric ligand–gated ion channels have provided unprecedented details of their molecular architecture. However, the conformational dynamics and structural rearrangements that underlie gating and allosteric modulation remain poorly understood. We used a combination of electrophysiology, double electron–electron resonance (DEER) spectroscopy, and x-ray crystallography to investigate activation mechanisms in a novel functional chimera with the extracellular domain (ECD) of amine-gated Erwinia chrysanthemi ligand–gated ion channel, which is activated by primary amines, and the transmembrane domain of Gloeobacter violaceus ligand–gated ion channel, which is activated by protons. We found that the chimera was independently gated by primarymore » amines and by protons. The crystal structure of the chimera in its resting state, at pH 7.0 and in the absence of primary amines, revealed a closed-pore conformation and an ECD that is twisted with respect to the transmembrane region. Amine- and pH-induced conformational changes measured by DEER spectroscopy showed that the chimera exhibits a dual mode of gating that preserves the distinct conformational changes of the parent channels. Collectively, our findings shed light on both conserved and divergent features of gating mechanisms in this class of channels, and will facilitate the design of better allosteric modulators.« less

A chimeric prokaryotic pentameric ligand–gated channel reveals distinct pathways of activation

PubMed Central

Schmandt, Nicolaus; Velisetty, Phanindra; Chalamalasetti, Sreevatsa V.; Stein, Richard A.; Bonner, Ross; Talley, Lauren; Parker, Mark D.; Mchaourab, Hassane S.; Yee, Vivien C.; Lodowski, David T.

2015-01-01

Recent high resolution structures of several pentameric ligand–gated ion channels have provided unprecedented details of their molecular architecture. However, the conformational dynamics and structural rearrangements that underlie gating and allosteric modulation remain poorly understood. We used a combination of electrophysiology, double electron–electron resonance (DEER) spectroscopy, and x-ray crystallography to investigate activation mechanisms in a novel functional chimera with the extracellular domain (ECD) of amine-gated Erwinia chrysanthemi ligand–gated ion channel, which is activated by primary amines, and the transmembrane domain of Gloeobacter violaceus ligand–gated ion channel, which is activated by protons. We found that the chimera was independently gated by primary amines and by protons. The crystal structure of the chimera in its resting state, at pH 7.0 and in the absence of primary amines, revealed a closed-pore conformation and an ECD that is twisted with respect to the transmembrane region. Amine- and pH-induced conformational changes measured by DEER spectroscopy showed that the chimera exhibits a dual mode of gating that preserves the distinct conformational changes of the parent channels. Collectively, our findings shed light on both conserved and divergent features of gating mechanisms in this class of channels, and will facilitate the design of better allosteric modulators. PMID:26415570

On the origins of oxygenic photosynthesis and aerobic respiration in Cyanobacteria.

PubMed

Soo, Rochelle M; Hemp, James; Parks, Donovan H; Fischer, Woodward W; Hugenholtz, Philip

2017-03-31

The origin of oxygenic photosynthesis in Cyanobacteria led to the rise of oxygen on Earth ~2.3 billion years ago, profoundly altering the course of evolution by facilitating the development of aerobic respiration and complex multicellular life. Here we report the genomes of 41 uncultured organisms related to the photosynthetic Cyanobacteria (class Oxyphotobacteria ), including members of the class Melainabacteria and a new class of Cyanobacteria (class Sericytochromatia ) that is basal to the Melainabacteria and Oxyphotobacteria All members of the Melainabacteria and Sericytochromatia lack photosynthetic machinery, indicating that phototrophy was not an ancestral feature of the Cyanobacteria and that Oxyphotobacteria acquired the genes for photosynthesis relatively late in cyanobacterial evolution. We show that all three classes independently acquired aerobic respiratory complexes, supporting the hypothesis that aerobic respiration evolved after oxygenic photosynthesis. Copyright © 2017, American Association for the Advancement of Science.

100-nm gate lithography for double-gate transistors

NASA Astrophysics Data System (ADS)

Krasnoperova, Azalia A.; Zhang, Ying; Babich, Inna V.; Treichler, John; Yoon, Jung H.; Guarini, Kathryn; Solomon, Paul M.

2001-09-01

The double gate field effect transistor (FET) is an exploratory device that promises certain performance advantages compared to traditional CMOS FETs. It can be scaled down further than the traditional devices because of the greater electrostatic control by the gates on the channel (about twice as short a channel length for the same gate oxide thickness), has steeper sub-threshold slope and about double the current for the same width. This paper presents lithographic results for double gate FET's developed at IBM's T. J. Watson Research Center. The device is built on bonded wafers with top and bottom gates self-aligned to each other. The channel is sandwiched between the top and bottom polysilicon gates and the gate length is defined using DUV lithography. An alternating phase shift mask was used to pattern gates with critical dimensions of 75 nm, 100 nm and 125 nm in photoresist. 50 nm gates in photoresist have also been patterned by 20% over-exposure of nominal 100 nm lines. No trim mask was needed because of a specific way the device was laid out. UV110 photoresist from Shipley on AR-3 antireflective layer were used. Process windows, developed and etched patterns are presented.

The impact of breathing guidance and prospective gating during thoracic 4DCT imaging: an XCAT study utilizing lung cancer patient motion

NASA Astrophysics Data System (ADS)

Pollock, Sean; Kipritidis, John; Lee, Danny; Bernatowicz, Kinga; Keall, Paul

2016-09-01

Two interventions to overcome the deleterious impact irregular breathing has on thoracic-abdominal 4D computed tomography (4DCT) are (1) facilitating regular breathing using audiovisual biofeedback (AVB), and (2) prospective respiratory gating of the 4DCT scan based on the real-time respiratory motion. The purpose of this study was to compare the impact of AVB and gating on 4DCT imaging using the 4D eXtended cardiac torso (XCAT) phantom driven by patient breathing patterns. We obtained simultaneous measurements of chest and abdominal walls, thoracic diaphragm, and tumor motion from 6 lung cancer patients under two breathing conditions: (1) AVB, and (2) free breathing. The XCAT phantom was used to simulate 4DCT acquisitions in cine and respiratory gated modes. 4DCT image quality was quantified by artefact detection (NCCdiff), mean square error (MSE), and Dice similarity coefficient of lung and tumor volumes (DSClung, DSCtumor). 4DCT acquisition times and imaging dose were recorded. In cine mode, AVB improved NCCdiff, MSE, DSClung, and DSCtumor by 20% (p  =  0.008), 23% (p  <  0.001), 0.5% (p  <  0.001), and 4.0% (p  <  0.003), respectively. In respiratory gated mode, AVB improved NCCdiff, MSE, and DSClung by 29% (p  <  0.001), 34% (p  <  0.001), 0.4% (p  <  0.001), respectively. AVB increased the cine acquisitions by 15 s and reduced respiratory gated acquisitions by 31 s. AVB increased imaging dose in cine mode by 10%. This was the first study to quantify the impact of breathing guidance and respiratory gating on 4DCT imaging. With the exception of DSCtumor in respiratory gated mode, AVB significantly improved 4DCT image analysis metrics in both cine and respiratory gated modes over free breathing. The results demonstrate that AVB and respiratory-gating can be beneficial interventions to improve 4DCT for cancer radiation therapy, with the biggest gains achieved when these interventions are used

SU-E-J-45: Design and Study of An In-House Respiratory Gating Phantom Platform for Gated Radiotherapy

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

Senthilkumar, S

2014-06-01

Purpose: The main purpose of this work was to develop an in-house low cost respiratory motion phantom platform for testing the accuracy of the gated radiotherapy system and analyze the dosimetric difference during gated radiotherapy. Methods: An in-house respiratory motion platform(RMP) was designed and constructed for testing the targeting accuracy of respiratory tracking system. The RMP consist of acrylic Chest Wall Platform, 2 DC motors, 4 IR sensors, speed controller circuit, 2 LED and 2 moving rods inside the RMP. The velocity of the movement can be varied from 0 to 30 cycles per minute. The platform mounted to amore » base using precision linear bearings. The base and platform are made of clear, 15mm thick polycarbonate plastic and the linear ball bearings are oriented to restrict the platform to a movement of approximately 50mm up and down with very little friction. Results: The targeting accuracy of the respiratory tracking system was evaluated using phantom with and without respiratory movement with varied amplitude. We have found the 5% dose difference to the PTV during the movement in comparison with stable PTV. The RMP can perform sinusoidal motion in 1D with fixed peak to peak motion of 5 to 50mm and cycle interval from 2 to 6 seconds. The RMP was designed to be able to simulate the gross anatomical anterior posterior motion attributable to respiration-induced motion of the thoracic region. Conclusion: The unique RMP simulates breathing providing the means to create a comprehensive program for commissioning, training, quality assurance and dose verification of gated radiotherapy treatments. Create the anterior/posterior movement of a target over a 5 to 50 mm distance to replicate tumor movement. The targeting error of the respiratory tracking system is less than 1.0 mm which shows suitable for clinical treatment with highly performance.« less

Radiation dose to workers due to the inhalation of dust during granite fabrication.

PubMed

Zwack, L M; McCarthy, W B; Stewart, J H; McCarthy, J F; Allen, J G

2014-03-01

There has been very little research conducted to determine internal radiation doses resulting from worker exposure to ionising radiation in granite fabrication shops. To address this issue, we estimated the effective radiation dose of granite workers in US fabrication shops who were exposed to the maximum respirable dust and silica concentrations allowed under current US regulations, and also to concentrations reported in the literature. Radiation doses were calculated using standard methods developed by the International Commission on Radiological Protection. The calculated internal doses were very low, and below both US occupational standards (50 mSv yr(-1)) and limits applicable to the general public (1 mSv yr(-1)). Workers exposed to respirable granite dust concentrations at the US Occupational Safety and Health Administration (OSHA) respirable dust permissible exposure limit (PEL) of 5 mg m(-3) over a full year had an estimated radiation dose of 0.062 mSv yr(-1). Workers exposed to respirable granite dust concentrations at the OSHA silica PEL and at the American Conference of Governmental Industrial Hygienists Threshold Limit Value for a full year had expected radiation doses of 0.007 mSv yr(-1) and 0.002 mSv yr(-1), respectively. Using data from studies of respirable granite dust and silica concentrations measured in granite fabrication shops, we calculated median expected radiation doses that ranged from <0.001 to 0.101 mSv yr(-1).

Comparison of Chest Pain Protocols for Electrocardiography-Gated Dual-Source Cardiothoracic CT in Children and Adults: The Effect of Tube Current Saturation on Radiation Dose Reduction

PubMed Central

2018-01-01

Objective To compare radiation doses between conventional and chest pain protocols using dual-source retrospectively electrocardiography (ECG)-gated cardiothoracic computed tomography (CT) in children and adults and assess the effect of tube current saturation on radiation dose reduction. Materials and Methods This study included 104 patients (16.6 ± 7.7 years, range 5–48 years) that were divided into two groups: those with and those without tube current saturation. The estimated radiation doses of retrospectively ECG-gated spiral cardiothoracic CT were compared between conventional, uniphasic, and biphasic chest pain protocols acquired with the same imaging parameters in the same patients by using paired t tests. Dose reduction percentages, patient ages, volume CT dose index values, and tube current time products per rotation were compared between the two groups by using unpaired t tests. A p value < 0.05 was considered significant. Results The volume CT dose index values of the biphasic chest pain protocol (10.8 ± 3.9 mGy) were significantly lower than those of the conventional protocol (12.2 ± 4.7 mGy, p < 0.001) and those of the uniphasic chest pain protocol (12.9 ± 4.9 mGy, p < 0.001). The dose-saving effect of biphasic chest pain protocol was significantly less with a saturated tube current (4.5 ± 10.2%) than with unsaturated tube current method (14.8 ± 11.5%, p < 0.001). In 76 patients using 100 kVp, patient age showed no significant differences between the groups with and without tube current saturation in all protocols (p > 0.05); the groups with tube current saturation showed significantly higher volume CT dose index values (p < 0.01) and tube current time product per rotation (p < 0.001) than the groups without tube current saturation in all protocols. Conclusion The radiation dose of dual-source retrospectively ECG-gated spiral cardiothoracic CT can be reduced by approximately 15% by using the biphasic chest pain protocol instead of the

Development of three methods for extracting respiration from the surface ECG: a review.

PubMed

Helfenbein, Eric; Firoozabadi, Reza; Chien, Simon; Carlson, Eric; Babaeizadeh, Saeed

2014-01-01

Respiration rate (RR) is a critical vital sign that can be monitored to detect acute changes in patient condition (e.g., apnea) and potentially provide an early warning of impending life-threatening deterioration. Monitoring respiration signals is also critical for detecting sleep disordered breathing such as sleep apnea. Additionally, analyzing a respiration signal can enhance the quality of medical images by gating image acquisition based on the same phase of the patient's respiratory cycle. Although many methods exist for measuring respiration, in this review we focus on three ECG-derived respiration techniques we developed to obtain respiration from an ECG signal. The first step in all three techniques is to analyze the ECG to detect beat locations and classify them. 1) The EDR method is based on analyzing the heart axis shift due to respiration. In our method, one respiration waveform value is calculated for each normal QRS complex by measuring the peak to QRS trough amplitude. Compared to other similar EDR techniques, this method does not need removal of baseline wander from the ECG signal. 2) The RSA method uses instantaneous heart rate variability to derive a respiratory signal. It is based on the observed respiratory sinus arrhythmia governed by baroreflex sensitivity. 3) Our EMGDR method for computing a respiratory waveform uses measurement of electromyogram (EMG) activity created by respiratory effort of the intercostal muscles and diaphragm. The ECG signal is high-pass filtered and processed to reduce ECG components and accentuate the EMG signal before applying RMS and smoothing. Over the last five years, we have performed six studies using the above methods: 1) In 1907 sleep lab patients with >1.5M 30-second epochs, EDR achieved an apnea detection accuracy of 79%. 2) In 24 adult polysomnograms, use of EDR and chest belts for RR computation was compared to airflow RR; mean RR error was EDR: 1.8±2.7 and belts: 0.8±2.1. 3) During cardiac MRI, a

31. The 1701B Main Gate House in March 1944, viewed ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. The 1701-B Main Gate House in March 1944, viewed to the northwest. Its clock alley provided controlled access to the 100-B Area. The second floor was used to read radiation-detecting pencil dosimeters and to replace radiation-detecting film badges worn by employees. P-2006 - B Reactor, Richland, Benton County, WA

TU-AB-BRA-10: Treatment of Gastric MALT Lymphoma Utilizing a Magnetic Resonance Image-Guided Radiation Therapy (MR-IGRT) System: Evaluation of Gating Feasibility

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

Mazur, T; Gach, H; Chundury, A

Purpose: To evaluate the feasibility of real-time, real-anatomy tracking and gating for gastric lymphoma patients treated with magnetic resonance image-guided radiation therapy (MR-IGRT) Methods: Over the last 2 years, 8 patients with gastric lymphoma were treated with 0.3-T, Co-60 MR-IGRT. Post-treatment analysis of real-time cine imaging in the sagittal plane during each patient’s treatment revealed significant motion of the stomach. While this motion was accounted for with generous PTV margins, the system’s capability for real-time, real-anatomy tracking could be used to reduce treatment margins by gating. However, analysis was needed for the feasibility of gating using only the single availablemore » sagittal imaging plane. While any plane may be chosen, if the stomach moves differently where it is not being observed, there may potentially be a mistreatment. To that end, imaging with healthy volunteers was done to ascertain stomach motion over 2–4 min by analyzing multiple parallel sagittal and coronal planes 0.75 cm apart. The stomach was contoured on every slice, and the mean displacement between pairs of contour centroids was used to determine the amount of overall motion. Results: The mean displacement of the centroid in the image plane was 4.3 ± 0.7 mm. The greatest observed motion was more medial with respect to the patient, and less motion laterally, which implies that gating on a plane located closer to MRI isocenter will provide the more conservative scenario as it will turn the radiation delivery off when the stomach is observed to move outside a predetermined boundary. Conclusion: The stomach was observed to move relatively uniformly throughout, with maximum extent of motion closer to where most MRI systems have the best spatial integrity (near isocenter). Analysis of possible PTV margins from the healthy volunteer study (coupled with previous patient data on interfraction volumetric stomach deformation) is pending.« less

Radiation Effects On Emerging Electronic Materials And Devices

DTIC Science & Technology

2010-01-17

RADIATION EFFECTS ON EMERGING ELECTRONIC MATERIALS AND DEVICES FINAL PERFORMANCE REPORT PREPARED FOR: Kitt Reinhardt AFOSR/NE 875 N...and the other with metal gates and a high-K gate dielectric. These devices were programmed using both back-gate pulse and gate induced drain leakage... metal gate process GIDL method Fig. 1. Sensing margin as a function of total ionizing dose for nMOS 1T-DRAM cells programmed by back-gate pulse and

The Ca{sup 2+} channel TRPML3 specifically interacts with the mammalian ATG8 homologue GATE16 to regulate autophagy

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

Choi, Suzy; Kim, Hyun Jin, E-mail: kimhyunjin@skku.edu

2014-01-03

Highlights: •Split-ubiquitin MY2H screen identified GATE16 as an interacting protein of TRPML3. •TRPML3 specifically binds to a mammalian ATG8 homologue GATE16, not to LC3B. •The interaction of TRPML3 with GATE16 facilitates autophagosome formation. •GATE16 is expressed in both autophagosome and extra-autophagosomal compartments. -- Abstract: TRPML3 is a Ca{sup 2+} permeable cation channel expressed in multiple intracellular compartments. Although TRPML3 is implicated in autophagy, how TRPML3 can regulate autophagy is not understood. To search interacting proteins with TRPML3 in autophagy, we performed split-ubiquitin membrane yeast two-hybrid (MY2H) screening with TRPML3-loop as a bait and identified GATE16, a mammalian ATG8 homologue. GSTmore » pull-down assay revealed that TRPML3 and TRPML3-loop specifically bind to GATE16, not to LC3B. Co-immunoprecipitation (co-IP) experiments showed that TRPML3 and TRPML3-loop pull down only the lipidated form of GATE16, indicating that the interaction occurs exclusively at the organellar membrane. The interaction of TRPML3 with GATE16 and GATE16-positive vesicle formation were increased in starvation induced autophagy, suggesting that the interaction facilitates the function of GATE16 in autophagosome formation. However, GATE16 was not required for TRPML3 trafficking to autophagosomes. Experiments using dominant-negative (DN) TRPML3(D458K) showed that GATE16 is localized not only in autophagosomes but also in extra-autophagosomal compartments, by contrast with LC3B. Since GATE16 acts at a later stage of the autophagosome biogenesis, our results suggest that TRPML3 plays a role in autophagosome maturation through the interaction with GATE16, by providing Ca{sup 2+} in the fusion process.« less

Hybrid respiration-signal conditioner

NASA Technical Reports Server (NTRS)

Rinard, G. A.; Steffen, D. A.; Sturm, R. E.

1979-01-01

Hybrid impedance-pneumograph and respiration-rate signal conditioner element of hand-held vital signs monitor measures changes in impedance of chest during breathing cycle and generates analog respiration signal as output along with synchronous square wave that can be monitored by breath-rate processor.

Organohalide Respiring Bacteria and Reductive Dehalogenases: Key Tools in Organohalide Bioremediation

PubMed Central

Jugder, Bat-Erdene; Ertan, Haluk; Bohl, Susanne; Lee, Matthew; Marquis, Christopher P.; Manefield, Michael

2016-01-01

Organohalides are recalcitrant pollutants that have been responsible for substantial contamination of soils and groundwater. Organohalide-respiring bacteria (ORB) provide a potential solution to remediate contaminated sites, through their ability to use organohalides as terminal electron acceptors to yield energy for growth (i.e., organohalide respiration). Ideally, this process results in non- or lesser-halogenated compounds that are mostly less toxic to the environment or more easily degraded. At the heart of these processes are reductive dehalogenases (RDases), which are membrane bound enzymes coupled with other components that facilitate dehalogenation of organohalides to generate cellular energy. This review focuses on RDases, concentrating on those which have been purified (partially or wholly) and functionally characterized. Further, the paper reviews the major bacteria involved in organohalide breakdown and the evidence for microbial evolution of RDases. Finally, the capacity for using ORB in a bioremediation and bioaugmentation capacity are discussed. PMID:26973626

SU-F-T-634: Feasibility Study of Respiratory Gated RapidArc SBRT Using a 6MV FFF Photon Beam

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

Dou, K; Safaraz, M; Rodgers, J

Purpose: To conduct a feasibility study on retrospective respiratory gating and marker tracking for lung stereotactic body radiotherapy (SBRT) with a gated RapidArc delivery using a 6MV flattened filter free photon mode. Methods: A CIRS dynamic thorax phantom Model 008A with different inserts was used for treatment planning and respiratory gating. 4D CT had a free breathing simulation followed by a respiration gated, ten phased CT using a Philips Brilliance CT with a Varian RPM respiratory gating system. The internal target volume was created from the ten phase gated CT images, followed by exporting to a Varian Eclipse TPS v11more » for treatment planning on the free breath images. Both MIP and AIP were also generated for comparison of planning and target motion tracking. The planned dose was delivered with a 6MV FFF photon beam from a Varian TrueBeam accelerator. Gated target motion was also verified by tracking the implanted makers during delivery using continuous kV imaging in addition to CBCT, kV and MV localization and verification. Results: Gating was studied in three situations of lower, normal, and faster breathing at a respiratory cycle of 5, 15 and 25 breaths per minute, respectively. 4D treatment planning was performed at a normal breathing of 15 breaths per minute. The gated patterns obtained using the TrueBeam IR camera were compared with the planned ones while gating operation was added prior to delivery . Gating was realized only when the measured respiratory patterns matched to the planned ones. The gated target motion was verified within the tolerance by kV and MV imaging. Either free breathing CT or averaged CT images were studied to be good for image guidance to align the target. Conclusion: Gated RapidArc SBRT delivered with a 6MV FFF photon beam is realized using a dynamic lung phantom.« less

Oxide-based synaptic transistors gated by solution-processed gelatin electrolytes

NASA Astrophysics Data System (ADS)

He, Yinke; Sun, Jia; Qian, Chuan; Kong, Ling-An; Gou, Guangyang; Li, Hongjian

2017-04-01

In human brain, a large number of neurons are connected via synapses. Simulation of the synaptic behaviors using electronic devices is the most important step for neuromorphic systems. In this paper, proton conducting gelatin electrolyte-gated oxide field-effect transistors (FETs) were used for emulating synaptic functions, in which the gate electrode is regarded as pre-synaptic neuron and the channel layer as the post-synaptic neuron. In analogy to the biological synapse, a potential spike can be applied at the gate electrode and trigger ionic motion in the gelatin electrolyte, which in turn generates excitatory post-synaptic current (EPSC) in the channel layer. Basic synaptic behaviors including spike time-dependent EPSC, paired-pulse facilitation (PPF), self-adaptation, and frequency-dependent synaptic transmission were successfully mimicked. Such ionic/electronic hybrid devices are beneficial for synaptic electronics and brain-inspired neuromorphic systems.

A novel fission-independent role of dynamin-related protein 1 in cardiac mitochondrial respiration

PubMed Central

Zhang, Huiliang; Wang, Pei; Bisetto, Sara; Yoon, Yisang; Chen, Quan; Sheu, Shey-Shing; Wang, Wang

2017-01-01

Aims Mitochondria in adult cardiomyocytes exhibit static morphology and infrequent dynamic changes, despite the high abundance of fission and fusion regulatory proteins in the heart. Previous reports have indicated that fusion proteins may bear functions beyond morphology regulation. Here, we investigated the role of fission protein, dynamin-related protein 1 (DRP1), on mitochondrial respiration regulation in adult cardiomyocytes. Methods and results By using genetic or pharmacological approaches, we manipulated the activity or protein level of fission and fusion proteins and found they mildly influenced mitochondrial morphology in adult rodent cardiomyocytes, which is in contrast to their significant effect in H9C2 cardiac myoblasts. Intriguingly, inhibiting endogenous DRP1 by dominant-negative DRP1 mutation (K38A), shRNA, or Mdivi-1 suppressed maximal respiration and respiratory control ratio in isolated mitochondria from adult mouse heart or in adult cardiomyocytes from rat. Meanwhile, basal respiration was increased due to increased proton leak. Facilitating mitofusin-mediated fusion by S3 compound, however, failed to inhibit mitochondrial respiration in adult cardiomyocytes. Mechanistically, DRP1 inhibition did not affect the maximal activity of individual respiratory chain complexes or the assembly of supercomplexes. Knocking out cyclophilin D, a regulator of mitochondrial permeability transition pore (mPTP), abolished the effect of DRP1 inhibition on respiration. Finally, DRP1 inhibition decreased transient mPTP-mediated mitochondrial flashes, delayed laser-induced mPTP opening and suppressed mitochondrial reactive oxygen species (ROS). Conclusion These results uncover a novel non-canonical function of the fission protein, DRP1 in maintaining or positively stimulating mitochondrial respiration, bioenergetics and ROS signalling in adult cardiomyocyte, which is likely independent of morphological changes. PMID:27794519

[Dark respiration of terrestrial vegetations: a review].

PubMed

Sun, Jin-Wei; Yuan, Feng-Hui; Guan, De-Xin; Wu, Jia-Bing

2013-06-01

The source and sink effect of terrestrial plants is one of the hotspots in terrestrial ecosystem research under the background of global change. Dark respiration of terrestrial plants accounts for a large fraction of total net carbon balance, playing an important role in the research of carbon cycle under global climate change. However, there is little study on plant dark respiration. This paper summarized the physiological processes of plant dark respiration, measurement methods of the dark respiration, and the effects of plant biology and environmental factors on the dark respiration. The uncertainty of the dark respiration estimation was analyzed, and the future hotspots of related researches were pointed out.

Contribution of bacterial respiration to plankton respiration from 50°N to 44°S in the Atlantic Ocean

NASA Astrophysics Data System (ADS)

García-Martín, E. E.; Aranguren-Gassis, M.; Hartmann, M.; Zubkov, M. V.; Serret, P.

2017-11-01

Marine bacteria play an important role in the global cycling of carbon and therefore in climate regulation. However, the paucity of direct measurements means that our understanding of the magnitude and variability of bacterial respiration in the ocean is poor. Estimations of respiration in the 0.2-0.8 μm size-fraction (considered as bacterial respiration), total plankton community respiration, and the contribution of bacterial respiration to total plankton community respiration were made along two latitudinal transects in the Atlantic Ocean (ca. 50°N-44°S) during 2010 and 2011. Two different methodologies were used: determination of changes in dissolved O2 concentration after standard 24 h dark bottle incubations, and measurements of in vivo reduction of 2-(ρ-iodophenyl)-3-(ρ-nitrophenyl)-5phenyl tetrazolium salt (INT). There was an overall significant correlation (r = 0.44, p < 0.0001, n = 90) between the rates of community respiration estimated by both methods. Depth-integrated community respiration varied as much as threefold between regions. Maximum rates occurred in waters of the western European shelf and Patagonian shelf, and minimum rates in the North and South oligotrophic gyres. Depth-integrated bacterial respiration followed the same pattern as community respiration. There was a significantly higher cell-specific bacterial respiration in the northern subtropical gyre than in the southern subtropical gyre which suggests that bacterial carbon turnover is faster in the northern gyre. The relationships between plankton respiration and physicochemical and biological variables were different in different years. In general, INTT was correlated to both chlorophyll-a and bacterial abundance, while INT0.2-0.8 was only correlated with bacterial abundance. However, in 2010 INTT and INT0.2-0.8 were also correlated with temperature and primary production while in 2011 they were correlated with nitrate + nitrite concentration. The bacterial contribution to depth

Does Short-term Litter Input Manipulation Affect Soil Respiration and the Carbon-isotopic Signature of Soil Respired CO2

NASA Astrophysics Data System (ADS)

Cheng, X.; Wu, J.

2016-12-01

Global change greatly alters the quality and quantity of plant litter inputs to soils, and further impacts soil organic matter (SOM) dynamics and soil respiration. However, the process-based understanding of how soil respiration may change with future shift in litter input is not fully understood. The Detritus Input and Removal Treatment (DIRT) experiment was conducted in coniferous forest (Platycladus orientalis (Linn.) Franco) ecosystem of central China to investigate the impact of above- and belowground litter input on soil respiration and the carbon-isotopic signature of soil respired CO2. Short-term (1-2 years) litter input manipulation significantly affected soil respiration, based on annual flux values, soil respiration was 31.9%, 20.5% and 37.2% lower in no litter (NL), no root (NR) and no input (NRNL), respectively, compared to control (CK). Whereas double litter (DL) treatment increased soil respiration by 9.1% compared to CK. The recalcitrance index of carbon (RIC) and the relative abundance of fungi increased under litter removal or root exclusion treatment (NL, NR and NRNL) compared to CK. Basal soil respiration was positively related to liable C and microbial biomass and negatively related to RIC and fungi to bacteria (F: B) ratio. The carbon-isotopic signature of soil respired CO2 enriched under litter removal and no input treatment, and slightly depleted under litter addition treatment compared to CK. Our results suggest that short-term litter input manipulation can affect the soil respiration by altering substrate availability and microbial community structure, and also impact the carbon-isotopic signature of soil respired CO2 possibly duo to change in the component of soil respiration and soil microclimate.

42 CFR 84.174 - Respirator containers; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Air-Purifying Particulate Respirators § 84.174 Respirator containers; minimum requirements. (a) Except... contamination of respirators which are not removed, and to prevent damage to respirators during transit. ...

Discrete taxa of saprotrophic fungi respire different ages of carbon from Antarctic soils.

PubMed

Newsham, Kevin K; Garnett, Mark H; Robinson, Clare H; Cox, Filipa

2018-05-18

Different organic compounds have distinct residence times in soil and are degraded by specific taxa of saprotrophic fungi. It hence follows that specific fungal taxa should respire carbon of different ages from these compounds to the atmosphere. Here, we test whether this is the case by radiocarbon ( 14 C) dating CO 2 evolved from two gamma radiation-sterilised maritime Antarctic soils inoculated with pure single cultures of four fungi. We show that a member of the Helotiales, which accounted for 41-56% of all fungal sequences in the two soils, respired soil carbon that was aged up to 1,200 years BP and which was 350-400 years older than that respired by the other three taxa. Analyses of the enzyme profile of the Helotialean fungus and the fluxes and δ 13 C values of CO 2 that it evolved suggested that its release of old carbon from soil was associated with efficient cellulose decomposition. Our findings support suggestions that increases in the ages of carbon respired from warmed soils may be caused by changes to the abundances or activities of discrete taxa of microbes, and indicate that the loss of old carbon from soils is driven by specific fungal taxa.

Effects of respirator use on worker performance

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

Cardarelli, R.

1995-03-01

In 1993, EPRI funded Yankee Atomic Electric Company to examine the effects of respirator use on worker efficiency. Phase I of Yankee`s effort was to develop a study design to determine respirator effects. Given success in Phase I, a larger population will be tested to determine if a stasitically significant respirator effect on performance can be measured. This paper summarizes the 1993 EPRI/Yankee Respirator Effects of Pilot Study, and describes the study design for the 1994 EPRI/Yankee Respirator Study to be conducted at the Oyster Creek Nuclear Power Plant. Also described is a summary of respirator effect studies that havemore » been conducted during the last ten (10) years.« less

Evoked pain analgesia in chronic pelvic pain patients using respiratory-gated auricular vagal afferent nerve stimulation.

PubMed

Napadow, Vitaly; Edwards, Robert R; Cahalan, Christine M; Mensing, George; Greenbaum, Seth; Valovska, Assia; Li, Ang; Kim, Jieun; Maeda, Yumi; Park, Kyungmo; Wasan, Ajay D

2012-06-01

Previous vagus nerve stimulation (VNS) studies have demonstrated antinociceptive effects, and recent noninvasive approaches, termed transcutaneous-vagus nerve stimulation (t-VNS), have utilized stimulation of the auricular branch of the vagus nerve in the ear. The dorsal medullary vagal system operates in tune with respiration, and we propose that supplying vagal afferent stimulation gated to the exhalation phase of respiration can optimize t-VNS. Counterbalanced, crossover study. Patients with chronic pelvic pain (CPP) due to endometriosis in a specialty pain clinic. INTERVENTIONS/OUTCOMES: We evaluated evoked pain analgesia for respiratory-gated auricular vagal afferent nerve stimulation (RAVANS) compared with nonvagal auricular stimulation (NVAS). RAVANS and NVAS were evaluated in separate sessions spaced at least 1 week apart. Outcome measures included deep-tissue pain intensity, temporal summation of pain, and anxiety ratings, which were assessed at baseline, during active stimulation, immediately following stimulation, and 15 minutes after stimulus cessation. RAVANS demonstrated a trend for reduced evoked pain intensity and temporal summation of mechanical pain, and significantly reduced anxiety in N = 15 CPP patients, compared with NVAS, with moderate to large effect sizes (η(2) > 0.2). Chronic pain disorders such as CPP are in great need of effective, nonpharmacological options for treatment. RAVANS produced promising antinociceptive effects for quantitative sensory testing (QST) outcomes reflective of the noted hyperalgesia and central sensitization in this patient population. Future studies should evaluate longer-term application of RAVANS to examine its effects on both QST outcomes and clinical pain. Wiley Periodicals, Inc.

Nonlinear properties of gated graphene in a strong electromagnetic field

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

Avetisyan, A. A., E-mail: artakav@ysu.am; Djotyan, A. P., E-mail: adjotyan@ysu.am; Moulopoulos, K., E-mail: cos@ucy.ac.cy

We develop a microscopic theory of a strong electromagnetic field interaction with gated bilayer graphene. Quantum kinetic equations for density matrix are obtained using a tight binding approach within second quantized Hamiltonian in an intense laser field. We show that adiabatically changing the gate potentials with time may produce (at resonant photon energy) a full inversion of the electron population with high density between valence and conduction bands. In the linear regime, excitonic absorption of an electromagnetic radiation in a graphene monolayer with opened energy gap is also studied.

Organic/inorganic hybrid synaptic transistors gated by proton conducting methylcellulose films

NASA Astrophysics Data System (ADS)

Wan, Chang Jin; Zhu, Li Qiang; Wan, Xiang; Shi, Yi; Wan, Qing

2016-01-01

The idea of building a brain-inspired cognitive system has been around for several decades. Recently, electric-double-layer transistors gated by ion conducting electrolytes were reported as the promising candidates for synaptic electronics and neuromorphic system. In this letter, indium-zinc-oxide transistors gated by proton conducting methylcellulose electrolyte films were experimentally demonstrated with synaptic plasticity including paired-pulse facilitation and spatiotemporal-correlated dynamic logic. More importantly, a model based on proton-related electric-double-layer modulation and stretched-exponential decay function was proposed, and the theoretical results are in good agreement with the experimentally measured synaptic behaviors.

Organic/inorganic hybrid synaptic transistors gated by proton conducting methylcellulose films

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

Wan, Chang Jin; Wan, Qing, E-mail: wanqing@nju.edu.cn, E-mail: yshi@nju.edu.cn; Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201

The idea of building a brain-inspired cognitive system has been around for several decades. Recently, electric-double-layer transistors gated by ion conducting electrolytes were reported as the promising candidates for synaptic electronics and neuromorphic system. In this letter, indium-zinc-oxide transistors gated by proton conducting methylcellulose electrolyte films were experimentally demonstrated with synaptic plasticity including paired-pulse facilitation and spatiotemporal-correlated dynamic logic. More importantly, a model based on proton-related electric-double-layer modulation and stretched-exponential decay function was proposed, and the theoretical results are in good agreement with the experimentally measured synaptic behaviors.

A novel optical gating method for laser gated imaging

NASA Astrophysics Data System (ADS)

Ginat, Ran; Schneider, Ron; Zohar, Eyal; Nesher, Ofer

2013-06-01

For the past 15 years, Elbit Systems is developing time-resolved active laser-gated imaging (LGI) systems for various applications. Traditional LGI systems are based on high sensitive gated sensors, synchronized to pulsed laser sources. Elbit propriety multi-pulse per frame method, which is being implemented in LGI systems, improves significantly the imaging quality. A significant characteristic of the LGI is its ability to penetrate a disturbing media, such as rain, haze and some fog types. Current LGI systems are based on image intensifier (II) sensors, limiting the system in spectral response, image quality, reliability and cost. A novel propriety optical gating module was developed in Elbit, untying the dependency of LGI system on II. The optical gating module is not bounded to the radiance wavelength and positioned between the system optics and the sensor. This optical gating method supports the use of conventional solid state sensors. By selecting the appropriate solid state sensor, the new LGI systems can operate at any desired wavelength. In this paper we present the new gating method characteristics, performance and its advantages over the II gating method. The use of the gated imaging systems is described in a variety of applications, including results from latest field experiments.

Basic study on the most relaxing respiration period in children to aid the development of a respiration-leading stuffed toy.

PubMed

Uratani, Hiroki; Yoshino, Kohzoh; Ohsuga, Mieko

2014-01-01

Following natural disasters, accidents, and shocking incidents, some children experience post-traumatic stress disorder (PTSD). The respiration control method, which relaxes the body and mind, may efficiently prevent PTSD. Therefore, we developed a stuffed toy that leads children's respiration using the up-and-down movement of the abdomen to help them relax. We investigated the most appropriate respiration period for children's relaxation. Data from studies on heart rate variability (HRV) biofeedback training suggest that breathing at the respiration period at which HRV is the highest is effective for improving chronic diseases. Therefore, we measured the relationship between the respiration period and physiological indices, including HRV. The participants were 10 children aged 5-12 years. HRV was the highest at a 10-12-s respiration period in all 10 children. However, the most suitable respiration period for smooth breathing and relaxation was different from that at which HRV is the highest. Therefore, the most relaxing respiration periods for children need to be determined by indices other than HRV.

External radioactive markers for PET data-driven respiratory gating in positron emission tomography.

PubMed

Büther, Florian; Ernst, Iris; Hamill, James; Eich, Hans T; Schober, Otmar; Schäfers, Michael; Schäfers, Klaus P

2013-04-01

Respiratory gating is an established approach to overcoming respiration-induced image artefacts in PET. Of special interest in this respect are raw PET data-driven gating methods which do not require additional hardware to acquire respiratory signals during the scan. However, these methods rely heavily on the quality of the acquired PET data (statistical properties, data contrast, etc.). We therefore combined external radioactive markers with data-driven respiratory gating in PET/CT. The feasibility and accuracy of this approach was studied for [(18)F]FDG PET/CT imaging in patients with malignant liver and lung lesions. PET data from 30 patients with abdominal or thoracic [(18)F]FDG-positive lesions (primary tumours or metastases) were included in this prospective study. The patients underwent a 10-min list-mode PET scan with a single bed position following a standard clinical whole-body [(18)F]FDG PET/CT scan. During this scan, one to three radioactive point sources (either (22)Na or (18)F, 50-100 kBq) in a dedicated holder were attached the patient's abdomen. The list mode data acquired were retrospectively analysed for respiratory signals using established data-driven gating approaches and additionally by tracking the motion of the point sources in sinogram space. Gated reconstructions were examined qualitatively, in terms of the amount of respiratory displacement and in respect of changes in local image intensity in the gated images. The presence of the external markers did not affect whole-body PET/CT image quality. Tracking of the markers led to characteristic respiratory curves in all patients. Applying these curves for gated reconstructions resulted in images in which motion was well resolved. Quantitatively, the performance of the external marker-based approach was similar to that of the best intrinsic data-driven methods. Overall, the gain in measured tumour uptake from the nongated to the gated images indicating successful removal of respiratory motion

Changes in soil respiration components and their specific respiration along three successional forests in the subtropics

DOE PAGES

Han, Tianfeng; Liu, Juxiu; Wang, Gangsheng; ...

2016-01-16

1.Understanding how soil respiration components change with forest succession is critical for modelling and predicting soil carbon (C) processes and its sequestration below-ground. The specific respiration (a ratio of respiration to biomass) is increasingly being used as an indicator of forest succession conceptually based on Odum's theory of ecosystem development. However, the hypothesis that specific soil respiration declines with forest succession remains largely untested. 2.We used a trenching method to partition soil respiration into heterotrophic respiration and autotrophic respiration (R H and R A) and then evaluated the specific R H and specific R A in three successional forests inmore » subtropical China. 3.Our results showed a clear seasonality in the influence of forest succession on R H, with no significant differences among the three forests in the dry season but a higher value in the old-growth forest than the other two forests in the wet season. R A in the old-growth forest tended to be the highest among the three forests. Both the specific R H and specific R A decreased with the progressive maturity of three forests. 4.Lastly, our results highlight the importance of forest succession in determining the variation of R H in different seasons. With forest succession, soil microbes and plant roots become more efficient to conserve C resources, which would result in a greater proportion of C retained in soils.« less

A novel fission-independent role of dynamin-related protein 1 in cardiac mitochondrial respiration.

PubMed

Zhang, Huiliang; Wang, Pei; Bisetto, Sara; Yoon, Yisang; Chen, Quan; Sheu, Shey-Shing; Wang, Wang

2017-02-01

Mitochondria in adult cardiomyocytes exhibit static morphology and infrequent dynamic changes, despite the high abundance of fission and fusion regulatory proteins in the heart. Previous reports have indicated that fusion proteins may bear functions beyond morphology regulation. Here, we investigated the role of fission protein, dynamin-related protein 1 (DRP1), on mitochondrial respiration regulation in adult cardiomyocytes. By using genetic or pharmacological approaches, we manipulated the activity or protein level of fission and fusion proteins and found they mildly influenced mitochondrial morphology in adult rodent cardiomyocytes, which is in contrast to their significant effect in H9C2 cardiac myoblasts. Intriguingly, inhibiting endogenous DRP1 by dominant-negative DRP1 mutation (K38A), shRNA, or Mdivi-1 suppressed maximal respiration and respiratory control ratio in isolated mitochondria from adult mouse heart or in adult cardiomyocytes from rat. Meanwhile, basal respiration was increased due to increased proton leak. Facilitating mitofusin-mediated fusion by S3 compound, however, failed to inhibit mitochondrial respiration in adult cardiomyocytes. Mechanistically, DRP1 inhibition did not affect the maximal activity of individual respiratory chain complexes or the assembly of supercomplexes. Knocking out cyclophilin D, a regulator of mitochondrial permeability transition pore (mPTP), abolished the effect of DRP1 inhibition on respiration. Finally, DRP1 inhibition decreased transient mPTP-mediated mitochondrial flashes, delayed laser-induced mPTP opening and suppressed mitochondrial reactive oxygen species (ROS). These results uncover a novel non-canonical function of the fission protein, DRP1 in maintaining or positively stimulating mitochondrial respiration, bioenergetics and ROS signalling in adult cardiomyocyte, which is likely independent of morphological changes. Published on behalf of the European Society of Cardiology. All rights reserved. © The

42 CFR 84.250 - Vinyl chloride respirators; description.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Vinyl chloride respirators; description. 84.250... Respirators § 84.250 Vinyl chloride respirators; description. Vinyl chloride respirators, including all... escape from vinyl chloride atmospheres containing adequate oxygen to support life, are described...

SU-E-T-56: A Novel Approach to Computing Expected Value and Variance of Point Dose From Non-Gated Radiotherapy Delivery

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

Zhou, S; Zhu, X; Zhang, M

Purpose: Randomness in patient internal organ motion phase at the beginning of non-gated radiotherapy delivery may introduce uncertainty to dose received by the patient. Concerns of this dose deviation from the planned one has motivated many researchers to study this phenomenon although unified theoretical framework for computing it is still missing. This study was conducted to develop such framework for analyzing the effect. Methods: Two reasonable assumptions were made: a) patient internal organ motion is stationary and periodic; b) no special arrangement is made to start a non -gated radiotherapy delivery at any specific phase of patient internal organ motion.more » A statistical ensemble was formed consisting of patient’s non-gated radiotherapy deliveries at all equally possible initial organ motion phases. To characterize the patient received dose, statistical ensemble average method is employed to derive formulae for two variables: expected value and variance of dose received by a patient internal point from a non-gated radiotherapy delivery. Fourier Series was utilized to facilitate our analysis. Results: According to our formulae, the two variables can be computed from non-gated radiotherapy generated dose rate time sequences at the point’s corresponding locations on fixed phase 3D CT images sampled evenly in time over one patient internal organ motion period. The expected value of point dose is simply the average of the doses to the point’s corresponding locations on the fixed phase CT images. The variance can be determined by time integration in terms of Fourier Series coefficients of the dose rate time sequences on the same fixed phase 3D CT images. Conclusion: Given a non-gated radiotherapy delivery plan and patient’s 4D CT study, our novel approach can predict the expected value and variance of patient radiation dose. We expect it to play a significant role in determining both quality and robustness of patient non-gated radiotherapy plan.« less

Mitochondrial respiration is sensitive to cytoarchitectural breakdown.

PubMed

Kandel, Judith; Angelin, Alessia A; Wallace, Douglas C; Eckmann, David M

2016-11-07

An abundance of research suggests that cellular mitochondrial and cytoskeletal disruption are related, but few studies have directly investigated causative connections between the two. We previously demonstrated that inhibiting microtubule and microfilament polymerization affects mitochondrial motility on the whole-cell level in fibroblasts. Since mitochondrial motility can be indicative of mitochondrial function, we now further characterize the effects of these cytoskeletal inhibitors on mitochondrial potential, morphology and respiration. We found that although they did not reduce mitochondrial inner membrane potential, cytoskeletal toxins induced significant decreases in basal mitochondrial respiration. In some cases, basal respiration was only affected after cells were pretreated with the calcium ionophore A23187 in order to stress mitochondrial function. In most cases, mitochondrial morphology remained unaffected, but extreme microfilament depolymerization or combined intermediate doses of microtubule and microfilament toxins resulted in decreased mitochondrial lengths. Interestingly, these two particular exposures did not affect mitochondrial respiration in cells not sensitized with A23187, indicating an interplay between mitochondrial morphology and respiration. In all cases, inducing maximal respiration diminished differences between control and experimental groups, suggesting that reduced basal respiration originates as a largely elective rather than pathological symptom of cytoskeletal impairment. However, viability experiments suggest that even this type of respiration decrease may be associated with cell death.

42 CFR 84.130 - Supplied-air respirators; description.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Supplied-air respirators; description. 84.130... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.130 Supplied-air respirators; description. Supplied-air respirators, including all completely...

42 CFR 84.130 - Supplied-air respirators; description.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Supplied-air respirators; description. 84.130... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.130 Supplied-air respirators; description. Supplied-air respirators, including all completely...

42 CFR 84.197 - Respirator containers; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.197... Cartridge Respirators § 84.197 Respirator containers; minimum requirements. Respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

Investigating the impact of audio instruction and audio-visual biofeedback for lung cancer radiation therapy

NASA Astrophysics Data System (ADS)

George, Rohini

Lung cancer accounts for 13% of all cancers in the Unites States and is the leading cause of deaths among both men and women. The five-year survival for lung cancer patients is approximately 15%.(ACS facts & figures) Respiratory motion decreases accuracy of thoracic radiotherapy during imaging and delivery. To account for respiration, generally margins are added during radiation treatment planning, which may cause a substantial dose delivery to normal tissues and increase the normal tissue toxicity. To alleviate the above-mentioned effects of respiratory motion, several motion management techniques are available which can reduce the doses to normal tissues, thereby reducing treatment toxicity and allowing dose escalation to the tumor. This may increase the survival probability of patients who have lung cancer and are receiving radiation therapy. However the accuracy of these motion management techniques are inhibited by respiration irregularity. The rationale of this thesis was to study the improvement in regularity of respiratory motion by breathing coaching for lung cancer patients using audio instructions and audio-visual biofeedback. A total of 331 patient respiratory motion traces, each four minutes in length, were collected from 24 lung cancer patients enrolled in an IRB-approved breathing-training protocol. It was determined that audio-visual biofeedback significantly improved the regularity of respiratory motion compared to free breathing and audio instruction, thus improving the accuracy of respiratory gated radiotherapy. It was also observed that duty cycles below 30% showed insignificant reduction in residual motion while above 50% there was a sharp increase in residual motion. The reproducibility of exhale based gating was higher than that of inhale base gating. Modeling the respiratory cycles it was found that cosine and cosine 4 models had the best correlation with individual respiratory cycles. The overall respiratory motion probability distribution

42 CFR 84.134 - Respirator containers; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.134... Respirators § 84.134 Respirator containers; minimum requirements. Supplied-air respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

Theory of the synchronous motion of an array of floating flap gates oscillating wave surge converter

NASA Astrophysics Data System (ADS)

Michele, Simone; Sammarco, Paolo; d'Errico, Michele

2016-08-01

We consider a finite array of floating flap gates oscillating wave surge converter (OWSC) in water of constant depth. The diffraction and radiation potentials are solved in terms of elliptical coordinates and Mathieu functions. Generated power and capture width ratio of a single gate excited by incoming waves are given in terms of the radiated wave amplitude in the far field. Similar to the case of axially symmetric absorbers, the maximum power extracted is shown to be directly proportional to the incident wave characteristics: energy flux, angle of incidence and wavelength. Accordingly, the capture width ratio is directly proportional to the wavelength, thus giving a design estimate of the maximum efficiency of the system. We then compare the array and the single gate in terms of energy production. For regular waves, we show that excitation of the out-of-phase natural modes of the array increases the power output, while in the case of random seas we show that the array and the single gate achieve the same efficiency.

Programmable Schottky Junctions Based on Ferroelectric Gated MoS2 Transistors

NASA Astrophysics Data System (ADS)

Xiao, Zhiyong; Song, Jingfeng; Drcharme, Stephen; Hong, Xia

We report a programmable Schottky junction based on MoS2 field effect transistors with a SiO2 back gate and a ferroelectric copolymer poly(vinylidene-fluoride-trifluorethylene) (PVDF) top gate. We fabricated mechanically exfoliated single layer MoS2 flakes into two point devices via e-beam lithography, and deposited on the top of the devices ~20 nm PVDF thin films. The polarization of the PVDF layer is controlled locally by conducting atomic force microscopy. The devices exhibit linear ID-VD characteristics when the ferroelectric gate is uniformly polarized in one direction. We then polarized the gate into two domains with opposite polarization directions, and observed that the ID-VD characteristics of the MoS2 channel can be modulated between linear and rectified behaviors depending on the back gate voltage. The nonlinear ID-VD relation emerges when half of the channel is in the semiconductor phase while the other half is in the metallic phase, and it can be well described by the thermionic emission model with a Schottky barrier of ~0.5 eV. The Schottky junction can be erased by re-write the entire channel in the uniform polarization state. Our study facilitates the development of programmable, multifunctional nanoelectronics based on layered 2D TMDs..

Niche divergence facilitated by fine-scale ecological partitioning in a recent cichlid fish adaptive radiation.

PubMed

Ford, Antonia G P; Rüber, Lukas; Newton, Jason; Dasmahapatra, Kanchon K; Balarin, John D; Bruun, Kristoffer; Day, Julia J

2016-12-01

Ecomorphological differentiation is a key feature of adaptive radiations, with a general trend for specialization and niche expansion following divergence. Ecological opportunity afforded by invasion of a new habitat is thought to act as an ecological release, facilitating divergence, and speciation. Here, we investigate trophic adaptive morphology and ecology of an endemic clade of oreochromine cichlid fishes (Alcolapia) that radiated along a herbivorous trophic axis following colonization of an isolated lacustrine environment, and demonstrate phenotype-environment correlation. Ecological and morphological divergence of the Alcolapia species flock are examined in a phylogenomic context, to infer ecological niche occupation within the radiation. Species divergence is observed in both ecology and morphology, supporting the importance of ecological speciation within the radiation. Comparison with an outgroup taxon reveals large-scale ecomorphological divergence but shallow genomic differentiation within the Alcolapia adaptive radiation. Ancestral morphological reconstruction suggests lake colonization by a generalist oreochromine phenotype that diverged in Lake Natron to varied herbivorous morphologies akin to specialist herbivores in Lakes Tanganyika and Malawi. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Radiation effects in LDD MOS devices

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

Woodruff, R.L.; Adams, J.R.

1987-12-01

The purpose of this work is to investigate the response of lightly doped drain (LDD) n-channel transistors to ionizing radiation. Transistors were fabricated with conventional (non-LDD) and lightly doped drain (LDD) structures using both standard (non-hardened) and radiation hardened gate oxides. Characterization of the transistors began with a correlation of the total-dose effects due to 10 keV x-rays with Co-60 gamma rays. The authors find that for the gate oxides and transistor structures investigated in this work, 10 keV x-rays produce more fixed-charge guild-up in the gate oxide, and more interface charge than do Co-60 gamma rays. They determined thatmore » the radiation response of LDD transistors is similar to that of conventional (non-LDD) transistors. In addition, both standard and radiation-hardened transistors subjected to hot carrier stress before irradiation show a similar radiation response. After exposure to 1.0 x 10/sup 6/ rads(Si), non-hardened transistors show increased susceptibility to hot-carrier graduation, while the radiation-hardened transistors exhibit similar hot-carrier degradation to non-irradiated devices. The authors have demonstrated a fully-integrated radiation hardened process tht is solid to 1.0 x 10/sup 6/ rads(Si), and shows promise for achieving 1.0 x 10/sup 7/ rad(Si) total-dose capability.« less

GaSe and GaTe anisotropic layered semiconductors for radiation detectors

NASA Astrophysics Data System (ADS)

Mandal, Krishna C.; Choi, Michael; Kang, Sung Hoon; Rauh, R. David; Wei, Jiuan; Zhang, Hui; Zheng, Lili; Cui, Y.; Groza, M.; Burger, A.

2007-09-01

High quality detector grade GaSe and GaTe single crystals have been grown by a modified vertical Bridgman technique using high purity Ga (7N) and in-house zone refined (ZR) precursor materials (Se and Te). A state-of-the-art computer model, MASTRAPP, is used to model heat and mass transfer in the Bridgman growth system and to predict the stress distribution in the as-grown crystals. The model accounts for heat transfer in the multiphase system, convection in the melt, and interface dynamics. The crystals harvested from ingots of 8-10 cm length and 2.5 cm diameter, have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, low temperature photoluminescence (PL), atomic force microscopy (AFM), and optical absorption/transmission measurements. Single element devices up to 1 cm2 in area have been fabricated from the crystals and tested as radiation detectors by measuring current-voltage (I-V) characteristics and pulse height spectra using 241Am source. The crystals have shown high promise as nuclear detectors with their high dark resistivity (>=10 9 Ω .cm), good charge transport properties (μτ e ~ 1.4x10 -5 cm2/V and μτ h ~ 1.5x10 -5 cm2/V), and relatively good energy resolution (~4% energy resolution at 60 keV). Details of numerical modeling and simulation, detector fabrication, and testing using a 241Am energy source (60 keV) is presented in this paper.

Gating of the designed trimeric/tetrameric voltage-gated H+ channel

PubMed Central

Fujiwara, Yuichiro; Kurokawa, Tatsuki; Takeshita, Kohei; Nakagawa, Atsushi; Larsson, H Peter; Okamura, Yasushi

2013-01-01

The voltage-gated H+ channel functions as a dimer, a configuration that is different from standard tetrameric voltage-gated channels. Each channel protomer has its own permeation pathway. The C-terminal coiled-coil domain has been shown to be necessary for both dimerization and cooperative gating in the two channel protomers. Here we report the gating cooperativity in trimeric and tetrameric Hv channels engineered by altering the hydrophobic core sequence of the coiled-coil assembly domain. Trimeric and tetrameric channels exhibited more rapid and less sigmoidal kinetics of activation of H+ permeation than dimeric channels, suggesting that some channel protomers in trimers and tetramers failed to produce gating cooperativity observed in wild-type dimers. Multimerization of trimer and tetramer channels were confirmed by the biochemical analysis of proteins, including crystallography. These findings indicate that the voltage-gated H+ channel is optimally designed as a dimeric channel on a solid foundation of the sequence pattern of the coiled-coil core, with efficient cooperative gating that ensures sustained and steep voltage-dependent H+ conductance in blood cells. PMID:23165764

Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

NASA Astrophysics Data System (ADS)

Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

2016-04-01

The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

Evoked Pain Analgesia in Chronic Pelvic Pain Patients using Respiratory-gated Auricular Vagal Afferent Nerve Stimulation

PubMed Central

Napadow, Vitaly; Edwards, Robert R; Cahalan, Christine M; Mensing, George; Greenbaum, Seth; Valovska, Assia; Li, Ang; Kim, Jieun; Maeda, Yumi; Park, Kyungmo; Wasan, Ajay D.

2012-01-01

Objective Previous Vagus Nerve Stimulation (VNS) studies have demonstrated anti-nociceptive effects, and recent non-invasive approaches; termed transcutaneous-VNS, or t-VNS, have utilized stimulation of the auricular branch of the vagus nerve in the ear. The dorsal medullary vagal system operates in tune with respiration, and we propose that supplying vagal afferent stimulation gated to the exhalation phase of respiration can optimize t-VNS. Design counterbalanced, crossover study. Patients patients with chronic pelvic pain (CPP) due to endometriosis in a specialty pain clinic. Interventions/Outcomes We evaluated evoked pain analgesia for Respiratory-gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) compared with Non-Vagal Auricular Stimulation (NVAS). RAVANS and NVAS were evaluated in separate sessions spaced at least one week apart. Outcome measures included deep tissue pain intensity, temporal summation of pain, and anxiety ratings, which were assessed at baseline, during active stimulation, immediately following stimulation, and 15 minutes after stimulus cessation. Results RAVANS demonstrated a trend for reduced evoked pain intensity and temporal summation of mechanical pain, and significantly reduced anxiety in N=15 CPP patients, compared to NVAS, with moderate to large effect sizes (eta2>0.2). Conclusion Chronic pain disorders such as CPP are in great need of effective, non-pharmacological options for treatment. RAVANS produced promising anti-nociceptive effects for QST outcomes reflective of the noted hyperalgesia and central sensitization in this patient population. Future studies should evaluate longer-term application of RAVANS to examine its effects on both QST outcomes and clinical pain. PMID:22568773

Peru upwelling plankton respiration: calculations of carbon flux, nutrient retention efficiency and heterotrophic energy production

NASA Astrophysics Data System (ADS)

Packard, T. T.; Osma, N.; Fernández-Urruzola, I.; Codispoti, L. A.; Christensen, J. P.; Gómez, M.

2014-11-01

Oceanic depth profiles of plankton respiration are described by a power function, RCO2 = (RCO2)0(z/z0)b similar to the vertical carbon flux profile. Furthermore, because both ocean processes are closely related, conceptually and mathematically, each can be calculated from the other. The exponent (b), always negative, defines the maximum curvature of the respiration depth-profile and controls the carbon flux. When b is large, the C flux (FC) from the epipelagic ocean is low and the nutrient retention efficiency (NRE) is high allowing these waters to maintain high productivity. The opposite occurs when b is small. This means that the attenuation of respiration in ocean water columns is critical in understanding and predicting both vertical FC as well as the capacity of epipelagic ecosystems to retain their nutrients. The NRE is a new metric defined as the ratio of nutrient regeneration in a seawater layer to the nutrients introduced into that layer via FC. A depth-profile of FC is the integral of water column respiration. This relationship facilitates calculating ocean sections of FC from water column respiration. In a FC section across the Peru upwelling system we found a FC maximum extending down to 400 m, 50 km off the Peru coast. Finally, coupling respiratory electron transport system activity to heterotrophic oxidative phosphorylation promoted the calculation of an ocean section of heterotrophic energy production (HEP). It ranged from 250 to 500 J d-1 m-3 in the euphotic zone, to less than 5 J d-1 m-3 below 200 m on this ocean section.

Radiation Mitigation and Power Optimization Design Tools for Reconfigurable Hardware in Orbit

NASA Technical Reports Server (NTRS)

French, Matthew; Graham, Paul; Wirthlin, Michael; Wang, Li; Larchev, Gregory

2005-01-01

The Reconfigurable Hardware in Orbit (RHinO)project is focused on creating a set of design tools that facilitate and automate design techniques for reconfigurable computing in space, using SRAM-based field-programmable-gate-array (FPGA) technology. In the second year of the project, design tools that leverage an established FPGA design environment have been created to visualize and analyze an FPGA circuit for radiation weaknesses and power inefficiencies. For radiation, a single event Upset (SEU) emulator, persistence analysis tool, and a half-latch removal tool for Xilinx/Virtex-II devices have been created. Research is underway on a persistence mitigation tool and multiple bit upsets (MBU) studies. For power, synthesis level dynamic power visualization and analysis tools have been completed. Power optimization tools are under development and preliminary test results are positive.

Majority logic gate for 3D magnetic computing.

PubMed

Eichwald, Irina; Breitkreutz, Stephan; Ziemys, Grazvydas; Csaba, György; Porod, Wolfgang; Becherer, Markus

2014-08-22

For decades now, microelectronic circuits have been exclusively built from transistors. An alternative way is to use nano-scaled magnets for the realization of digital circuits. This technology, known as nanomagnetic logic (NML), may offer significant improvements in terms of power consumption and integration densities. Further advantages of NML are: non-volatility, radiation hardness, and operation at room temperature. Recent research focuses on the three-dimensional (3D) integration of nanomagnets. Here we show, for the first time, a 3D programmable magnetic logic gate. Its computing operation is based on physically field-interacting nanometer-scaled magnets arranged in a 3D manner. The magnets possess a bistable magnetization state representing the Boolean logic states '0' and '1.' Magneto-optical and magnetic force microscopy measurements prove the correct operation of the gate over many computing cycles. Furthermore, micromagnetic simulations confirm the correct functionality of the gate even for a size in the nanometer-domain. The presented device demonstrates the potential of NML for three-dimensional digital computing, enabling the highest integration densities.

A distinct seasonal pattern of the ratio of soil respiration to total ecosystem respiration in a spruce-dominated forest

Treesearch

E.A. Davidson; A.D. Richardson; K.E. Savage; D.Y. Hollinger

2006-01-01

Annual budgets and fitted temperature response curves for soil respiration and ecosystem respiration provide useful information for partitioning annual carbon budgets of ecosystems, but they may not adequately reveal seasonal variation in the ratios of these two fluxes. Soil respiration (Rs) typically contributes 30-80% of...

Occupational Exposure to Respirable Dust, Respirable Crystalline Silica and Diesel Engine Exhaust Emissions in the London Tunnelling Environment.

PubMed

Galea, Karen S; Mair, Craig; Alexander, Carla; de Vocht, Frank; van Tongeren, Martie

2016-03-01

Personal 8-h shift exposure to respirable dust, diesel engine exhaust emissions (DEEE) (as respirable elemental carbon), and respirable crystalline silica of workers involved in constructing an underground metro railway tunnel was assessed. Black carbon (BC) concentrations were also assessed using a MicroAeth AE51. During sprayed concrete lining (SCL) activities in the tunnel, the geometric mean (GM) respirable dust exposure level was 0.91mg m(-3), with the highest exposure measured on a back-up sprayer (3.20mg m(-3)). The GM respirable crystalline silica concentration for SCL workers was 0.03mg m(-3), with the highest measurement also for the back-up sprayer (0.24mg m(-3)). During tunnel boring machine (TBM) activities, the GM respirable dust concentration was 0.54mg m(-3). The GM respirable elemental carbon concentration for all the TBM operators was 18 µg m(-3); with the highest concentration measured on a segment lifter. The BC concentrations were higher in the SCL environment in comparison to the TBM environment (daily GM 18-54 µg m(-3) versus 3-6 µg m(-3)). This small-scale monitoring campaign provides additional personal data on exposures experienced by underground tunnel construction workers. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Towards a controlled-phase gate using Rydberg-dressed atoms

NASA Astrophysics Data System (ADS)

Hankin, Aaron; Jau, Yuan-Yu; Biedermann, Grant

2014-05-01

We are implementing a controlled-phase gate based on singly trapped neutral atoms whose coupling is mediated by the dipole-dipole interaction of Rydberg states. An off-resonant laser field dresses ground state cesium atoms in a manner conditional on the Rydberg blockade mechanism, providing the required entangling interaction. We will present our progress toward implementing the controlled-phase gate with an analysis of possible sources of decoherence such as RF radiation from wireless communication devices. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Clinical pulmonary function and industrial respirator wear

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

Raven, P.B.; Moss, R.F.; Page, K.

1981-12-01

This investigation was the initial step in determining a clinical pulmonary test which could be used to evaluate workers as to their suitability to industrial respirator wear. Sixty subjects, 12 superior, 37 normal, and 11 moderately impaired with respect to lung function tests were evaluated with a battery of clinical pulmonary tests while wearing an industrial respirator. The respirator was a full-face mask (MSA-Ultravue) demand breathing type equipped with an inspiratory resistance of 85mm H/sub 2/O at 85 L/min air flow and an expiratory resistance of 25mm H/sub 2/O at 85 L/min air flow. Comparisons of these tests were mademore » between the three groups of subjects both with and without a respirator. It appears that those lung tests which measure the flow characteristics of the lung especially those that are effort dependant are more susceptible to change as a result of respirator wear. Hence, the respirator affects the person with superior lung function to a greater degree than the moderately impaired person. It was suggested that the clinical test of 15 second maximum voluntary ventilations (MVV./sub 25/) may be the test of choice for determining worker capability in wearing an industrial respirator.« less

Gating modifier toxins isolated from spider venom: modulation of voltage-gated sodium channels and the role of lipid membranes.

PubMed

Agwa, Akello J; Peigneur, Steve; Chow, Chun Yuen; Lawrence, Nicole; Craik, David J; Tytgat, Jan; King, Glenn F; Henriques, Sonia Troeira; Schroeder, Christina I

2018-04-27

Gating modifier toxins (GMTs) are venom-derived peptides isolated from spiders and other venomous creatures that modulate activity of disease-relevant voltage-gated ion channels and are therefore being pursued as therapeutic leads. The amphipathic surface profile of GMTs has prompted the proposal that some GMTs simultaneously bind to the cell membrane and voltage-gated ion channels in a trimolecular complex. Here we examined whether there is a relationship among spider GMT amphipathicity, membrane binding and potency or selectivity for voltage-gated sodium (NaV) channels. We used NMR spectroscopy and in silico calculations to examine the structures and physicochemical properties of a panel of nine GMTs and deployed surface plasmon resonance to measure GMT affinity for lipids putatively found in proximity to NaV channels. Electrophysiology was used to quantify GMT activity on NaV1.7, an ion channel linked to chronic pain. Selectivity of the peptides was further examined against a panel of NaV channel subtypes. We show that GMTs adsorb to the outer leaflet of anionic lipid bilayers through electrostatic interactions. We did not observe a direct correlation between GMT amphipathicity and affinity for lipid bilayers. Furthermore, GMT-lipid bilayer interactions did not correlate with potency or selectivity for NaVs. We therefore propose that increased membrane binding is unlikely to improve subtype selectivity and that the conserved amphipathic GMT surface profile is an adaptation that facilitates simultaneous modulation of multiple NaVs. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Sliding-gate valve

DOEpatents

Usnick, George B.; Ward, Gene T.; Blair, Henry O.; Roberts, James W.; Warner, Terry N.

1979-01-01

This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

PubMed

Sperling, Or; Earles, J Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

2015-01-01

Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm(-3) yr(-1) on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

Frost Induces Respiration and Accelerates Carbon Depletion in Trees

PubMed Central

Sperling, Or; Earles, J. Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A.

2015-01-01

Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0°C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm-3 yr-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics. PMID:26629819

Measuring respiration rates in marine fish larvae: challenges and advances.

PubMed

Peck, M A; Moyano, M

2016-01-01

Metabolic costs can be extremely high in marine fish larvae and gaining reliable estimates of the effects of intrinsic and extrinsic factors on those costs is important to understand environmental constraints on early growth and survival. This review provides an historical perspective of measurements of larval marine fish respiration (O2 consumption) including the methods (Winkler, manometric, polarographic, paramagnetic and optodes) and systems (closed system to intermittent-flow) used. This study compares and systematically reviews the results (metabolic rates, ontogenetic changes and taxonomic differences) obtained from 59 studies examining 53 species from 30 families. Standard (anaesthetized or darkness), routine and active respiration rates were reported in 14, 94 and 8% of the studies and much more work has been performed on larvae of temperate (88%) compared with tropical (9%) and polar (3%) species. More than 35% of the studies have been published since 2000 owing to both advances in oxygen sensors and the growing emphasis on understanding physiological effects of environmental change. Common protocols are needed to facilitate cross-taxa comparisons such as the effect of temperature (Q10 : 1·47-3·47), body mass (slope of allometric changes in O2 consumption rate from 0·5 to 1·3) and activity level on metabolic costs as measured via respiration rate. A set of recommendations is provided that will make it easier for researchers to design measurement systems, to judge the reliability of measurements and to make inter-comparisons among studies and species. © 2016 The Fisheries Society of the British Isles.

Evaluation of respiratory and cardiac motion correction schemes in dual gated PET/CT cardiac imaging.

PubMed

Lamare, F; Le Maitre, A; Dawood, M; Schäfers, K P; Fernandez, P; Rimoldi, O E; Visvikis, D

2014-07-01

Cardiac imaging suffers from both respiratory and cardiac motion. One of the proposed solutions involves double gated acquisitions. Although such an approach may lead to both respiratory and cardiac motion compensation there are issues associated with (a) the combination of data from cardiac and respiratory motion bins, and (b) poor statistical quality images as a result of using only part of the acquired data. The main objective of this work was to evaluate different schemes of combining binned data in order to identify the best strategy to reconstruct motion free cardiac images from dual gated positron emission tomography (PET) acquisitions. A digital phantom study as well as seven human studies were used in this evaluation. PET data were acquired in list mode (LM). A real-time position management system and an electrocardiogram device were used to provide the respiratory and cardiac motion triggers registered within the LM file. Acquired data were subsequently binned considering four and six cardiac gates, or the diastole only in combination with eight respiratory amplitude gates. PET images were corrected for attenuation, but no randoms nor scatter corrections were included. Reconstructed images from each of the bins considered above were subsequently used in combination with an affine or an elastic registration algorithm to derive transformation parameters allowing the combination of all acquired data in a particular position in the cardiac and respiratory cycles. Images were assessed in terms of signal-to-noise ratio (SNR), contrast, image profile, coefficient-of-variation (COV), and relative difference of the recovered activity concentration. Regardless of the considered motion compensation strategy, the nonrigid motion model performed better than the affine model, leading to higher SNR and contrast combined with a lower COV. Nevertheless, when compensating for respiration only, no statistically significant differences were observed in the performance of the

Evaluation of respiratory and cardiac motion correction schemes in dual gated PET/CT cardiac imaging

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

Lamare, F., E-mail: frederic.lamare@chu-bordeaux.fr; Fernandez, P.; CNRS, INCIA, UMR 5287, F-33400 Talence

Purpose: Cardiac imaging suffers from both respiratory and cardiac motion. One of the proposed solutions involves double gated acquisitions. Although such an approach may lead to both respiratory and cardiac motion compensation there are issues associated with (a) the combination of data from cardiac and respiratory motion bins, and (b) poor statistical quality images as a result of using only part of the acquired data. The main objective of this work was to evaluate different schemes of combining binned data in order to identify the best strategy to reconstruct motion free cardiac images from dual gated positron emission tomography (PET)more » acquisitions. Methods: A digital phantom study as well as seven human studies were used in this evaluation. PET data were acquired in list mode (LM). A real-time position management system and an electrocardiogram device were used to provide the respiratory and cardiac motion triggers registered within the LM file. Acquired data were subsequently binned considering four and six cardiac gates, or the diastole only in combination with eight respiratory amplitude gates. PET images were corrected for attenuation, but no randoms nor scatter corrections were included. Reconstructed images from each of the bins considered above were subsequently used in combination with an affine or an elastic registration algorithm to derive transformation parameters allowing the combination of all acquired data in a particular position in the cardiac and respiratory cycles. Images were assessed in terms of signal-to-noise ratio (SNR), contrast, image profile, coefficient-of-variation (COV), and relative difference of the recovered activity concentration. Results: Regardless of the considered motion compensation strategy, the nonrigid motion model performed better than the affine model, leading to higher SNR and contrast combined with a lower COV. Nevertheless, when compensating for respiration only, no statistically significant differences were

42 CFR 84.191 - Chemical cartridge respirators; required components.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

42 CFR 84.191 - Chemical cartridge respirators; required components.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

42 CFR 84.191 - Chemical cartridge respirators; required components.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

42 CFR 84.191 - Chemical cartridge respirators; required components.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

42 CFR 84.191 - Chemical cartridge respirators; required components.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

Image-guided adaptive gating of lung cancer radiotherapy: a computer simulation study

NASA Astrophysics Data System (ADS)

Aristophanous, Michalis; Rottmann, Joerg; Park, Sang-June; Nishioka, Seiko; Shirato, Hiroki; Berbeco, Ross I.

2010-08-01

regularity of the breathing pattern suggesting that image-guided adaptive gating should be combined with breath coaching. The adaptive gating window technique was able to track the exhale position of the breathing cycle quite successfully. Out of a total of 53 fractions the duty cycle was greater than 20% for 42 fractions for the fixed gating window technique and for 39 fractions for the adaptive gating window technique. The results of this study suggest that real-time updating of the gating window can result in reliably low residual tumor motion and therefore can facilitate safe margin reduction.

ISAC's Gating-ML 2.0 data exchange standard for gating description.

PubMed

Spidlen, Josef; Moore, Wayne; Brinkman, Ryan R

2015-07-01

The lack of software interoperability with respect to gating has traditionally been a bottleneck preventing the use of multiple analytical tools and reproducibility of flow cytometry data analysis by independent parties. To address this issue, ISAC developed Gating-ML, a computer file format to encode and interchange gates. Gating-ML 1.5 was adopted and published as an ISAC Candidate Recommendation in 2008. Feedback during the probationary period from implementors, including major commercial software companies, instrument vendors, and the wider community, has led to a streamlined Gating-ML 2.0. Gating-ML has been significantly simplified and therefore easier to support by software tools. To aid developers, free, open source reference implementations, compliance tests, and detailed examples are provided to stimulate further commercial adoption. ISAC has approved Gating-ML as a standard ready for deployment in the public domain and encourages its support within the community as it is at a mature stage of development having undergone extensive review and testing, under both theoretical and practical conditions. © 2015 International Society for Advancement of Cytometry.

DNAzyme-Based Logic Gate-Mediated DNA Self-Assembly.

PubMed

Zhang, Cheng; Yang, Jing; Jiang, Shuoxing; Liu, Yan; Yan, Hao

2016-01-13

Controlling DNA self-assembly processes using rationally designed logic gates is a major goal of DNA-based nanotechnology and programming. Such controls could facilitate the hierarchical engineering of complex nanopatterns responding to various molecular triggers or inputs. Here, we demonstrate the use of a series of DNAzyme-based logic gates to control DNA tile self-assembly onto a prescribed DNA origami frame. Logic systems such as "YES," "OR," "AND," and "logic switch" are implemented based on DNAzyme-mediated tile recognition with the DNA origami frame. DNAzyme is designed to play two roles: (1) as an intermediate messenger to motivate downstream reactions and (2) as a final trigger to report fluorescent signals, enabling information relay between the DNA origami-framed tile assembly and fluorescent signaling. The results of this study demonstrate the plausibility of DNAzyme-mediated hierarchical self-assembly and provide new tools for generating dynamic and responsive self-assembly systems.

Monte Carlo Simulation of THz Radiation Detection in GaN MOSFET n+nn+ Channel with Uncentered Gate in n-region

NASA Astrophysics Data System (ADS)

Palermo, C.; Torres, J.; Varani, L.; Gružinskis, V.; Starikov, E.; Shiktorov, P.; Ašmontas, S.; Sužiedelis, A.

2017-10-01

Electron transport and drain current noise in the wurtzite GaN MOSFET have been studied by Monte Carlo particle simulation which simultaneously solves the Boltzmann transport and pseudo-2D Poisson equations. A proper design of GaN MOSFET n+nn+ channel with uncentered gate in n-region to reach the maximum detection sensitivity is proposed. It is shown that the main role in formation of longitudinal transport asymmetry and THz radiation detection is played by optical phonon emission process. It is found that the detection current at 300 K is maximal in frequency range from 0.5 to 7 THz. At higher frequenciea the detection current rapidly decreases due to the inertia of electron motion.

Reversible temperature-dependent differences in brown adipose tissue respiration during torpor in a mammalian hibernator.

PubMed

McFarlane, Sarah V; Mathers, Katherine E; Staples, James F

2017-03-01

Although seasonal modifications of brown adipose tissue (BAT) in hibernators are well documented, we know little about functional regulation of BAT in different phases of hibernation. In the 13-lined ground squirrel, liver mitochondrial respiration is suppressed by up to 70% during torpor. This suppression is reversed during arousal and interbout euthermia (IBE), and corresponds with patterns of maximal activities of electron transport system (ETS) enzymes. Uncoupling of BAT mitochondria is controlled by free fatty acid release stimulated by sympathetic activation of adipocytes, so we hypothesized that further regulation at the level of the ETS would be of little advantage. As predicted, maximal ETS enzyme activities of isolated BAT mitochondria did not differ between torpor and IBE. In contrast to this pattern, respiration rates of mitochondria isolated from torpid individuals were suppressed by ~60% compared with rates from IBE individuals when measured at 37°C. At 10°C, however, mitochondrial respiration rates tended to be greater in torpor than IBE. As a result, the temperature sensitivity (Q 10 ) of mitochondrial respiration was significantly lower in torpor (~1.4) than IBE (~2.4), perhaps facilitating energy savings during entrance into torpor and thermogenesis at low body temperatures. Despite the observed differences in isolated mitochondria, norepinephrine-stimulated respiration rates of isolated BAT adipocytes did not differ between torpor and IBE, perhaps because the adipocyte isolation requires lengthy incubation at 37°C, potentially reversing any changes that occur in torpor. Such changes may include remodeling of BAT mitochondrial membrane phospholipids, which could change in situ enzyme activities and temperature sensitivities. Copyright © 2017 the American Physiological Society.

Cross-correlation of heartbeat and respiration rhythms

NASA Astrophysics Data System (ADS)

Capurro, A.; Malta, C. P.; Diambra, L.; Contreras, P.; Migliaro, E. R.

2005-10-01

The cross-correlation function between respiration and heart beat interval series shows that during metronomized breathing the heart beat follows the respiration more closely than during spontaneous breathing. We reproduced the heart beat interval modulations during metronomized breathing using a biophysical model of the sinoatrial node excited by an input signal formed by the recorded respiration. In the case of spontaneous breathing, a good agreement with the experimental data was obtained only by using an input signal formed by the sum of the recorded respiration and a realization of correlated noise. Metronomized breathing refers to the situation where a subject breathes following the rhythm of a metronome.

BOREAS TE-5 Soil Respiration Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry

2000-01-01

The BOREAS TE-5 team collected measurements in the NSA and SSA on gas exchange, gas composition, and tree growth. Soil respiration data were collected from 26-May-94 to 07-Sep-94 in the BOREAS NSA and SSA to compare the soil respiration rates in different forest sites using a LI-COR 6200 soil respiration chamber (model 6299). The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distrobuted Activity Archive Center (DAAC).

42 CFR 84.190 - Chemical cartridge respirators: description.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

42 CFR 84.190 - Chemical cartridge respirators: description.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

42 CFR 84.190 - Chemical cartridge respirators: description.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

42 CFR 84.190 - Chemical cartridge respirators: description.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

42 CFR 84.190 - Chemical cartridge respirators: description.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

Respirator Performance against Nanoparticles under Simulated Workplace Activities

PubMed Central

Vo, Evanly; Zhuang, Ziqing; Horvatin, Matthew; Liu, Yuewei; He, Xinjian; Rengasamy, Samy

2017-01-01

Filtering facepiece respirators (FFRs) and elastomeric half-mask respirators (EHRs) are commonly used by workers for protection against potentially hazardous particles, including engineered nanoparticles. The purpose of this study was to evaluate the performance of these types of respirators against 10–400 nm particles using human subjects exposed to NaCl aerosols under simulated workplace activities. Simulated workplace protection factors (SWPFs) were measured for eight combinations of respirator models (2 N95 FFRs, 2 P100 FFRs, 2 N95 EHRs, and 2 P100 EHRs) worn by 25 healthy test subjects (13 females and 12 males) with varying face sizes. Before beginning a SWPF test for a given respirator model, each subject had to pass a quantitative fit test. Each SWPF test was performed using a protocol of six exercises for 3 min each: (i) normal breathing, (ii) deep breathing, (iii) moving head side to side, (iv) moving head up and down, (v) bending at the waist, and (vi) a simulated laboratory-vessel cleaning motion. Two scanning mobility particle sizers were used simultaneously to measure the upstream (outside the respirator) and downstream (inside the respirator) test aerosol; SWPF was then calculated as a ratio of the upstream and downstream particle concentrations. In general, geometric mean SWPF (GM-SWPF) was highest for the P100 EHRs, followed by P100 FFRs, N95 EHRs, and N95 FFRs. This trend holds true for nanoparticles (10–100 nm), larger size particles (100–400 nm), and the ‘all size’ range (10–400 nm). All respirators provided better or similar performance levels for 10–100 nm particles as compared to larger 100–400 nm particles. This study found that class P100 respirators provided higher SWPFs compared to class N95 respirators (P<0.05) for both FFR and EHR types. All respirators provided expected performance (i.e. fifth percentile SWPF > 10) against all particle size ranges tested. PMID:26180261

RESPIRATION AND INTENSITY DEPENDENCE OF PHOTOSYNTHESIS IN CHLORELLA

PubMed Central

Brackett, Frederick S.; Olson, Rodney A.; Crickard, Robert G.

1953-01-01

1. Respiration changes as a result of illumination. 2. In the absence of glucose or other supply of substrate, respiration decays in the dark showing at least two types—a fast decay in a few minutes and a slow decay lasting hours. 3. Respiratory response to illumination is delayed. 4. Intermittent illumination (in the absence of glucose, etc.) produces a periodic variation in respiration with a delay or phase lag. 5. Periodic variation of respiration may produce a higher average value in the dark than in the light due to the lag and depending upon the period of intermittent illumination. 6. Based upon average respiration values our data confirm the Kok effect. 7. Interpolated values of respiration, however, result in photosynthetic rates which are linearly dependent upon intensity of illumination. 8. Thus the quantum efficiency is found to be independent of intensity, over the wide range of intensities investigated. PMID:13035068

Coronary CT Angiography Incorporating Doppler-Guided Prospective ECG Gating in Patients with High Heart Rate: Comparison with Results of Traditional Prospective ECG Gating

PubMed Central

Li, Min; Yu, Bing-bing; Wu, Jian-hua; Xu, Lin; Sun, Gang

2013-01-01

Purpose As Doppler ultrasound has been proven to be an effective tool to predict and compress the optimal pulsing windows, we evaluated the effective dose and diagnostic accuracy of coronary CT angiography (CTA) incorporating Doppler-guided prospective electrocardiograph (ECG) gating, which presets pulsing windows according to Doppler analysis, in patients with a heart rate >65 bpm. Materials and Methods 119 patients with a heart rate >65 bpm who were scheduled for invasive coronary angiography were prospectively studied, and patients were randomly divided into traditional prospective (n = 61) and Doppler-guided prospective (n = 58) ECG gating groups. The exposure window of traditional prospective ECG gating was set at 30%–80% of the cardiac cycle. For the Doppler group, the length of diastasis was analyzed by Doppler. For lengths greater than 90 ms, the pulsing window was preset during diastole (during 60%–80%); otherwise, the optimal pulsing intervals were moved from diastole to systole (during 30%–50%). Results The mean heart rates of the traditional ECG and the Doppler-guided group during CT scanning were 75.0±7.7 bpm (range, 66–96 bpm) and 76.5±5.4 bpm (range: 66–105 bpm), respectively. The results indicated that whereas the image quality showed no significant difference between the traditional and Doppler groups (P = 0.42), the radiation dose of the Doppler group was significantly lower than that of the traditional group (5.2±3.4mSv vs. 9.3±4.5mSv, P<0.001). The sensitivities of CTA applying traditional and Doppler-guided prospective ECG gating to diagnose stenosis on a segment level were 95.5% and 94.3%, respectively; specificities 98.0% and 97.1%, respectively; positive predictive values 90.7% and 88.2%, respectively; negative predictive values 99.0% and 98.7%, respectively. There was no statistical difference in concordance between the traditional and Doppler groups (P = 0.22). Conclusion Doppler-guided prospective ECG gating

What controls respiration rate in stored sugarbeet roots

USDA-ARS?s Scientific Manuscript database

Although respiration is estimated to be responsible for 60 to 80% of the sucrose lost during storage, the mechanisms by which sugarbeet roots regulate their respiration rate are unknown. In plants, respiration rate is regulated by (1) available respiratory capacity, (2) cellular energy status, (3) ...

An Evaluation of an Aftermarket Local Exhaust Ventilation Device for Suppressing Respirable Dust and Respirable Crystalline Silica Dust from Powered Saws

PubMed Central

Garcia, Alberto; Jones, Erica; Echt, Alan S.; Hall, Ronald M.

2015-01-01

The objective of this study was to quantify the respirable dust and respirable silica exposures of roofing workers using an electric powered circular saw with an aftermarket local exhaust ventilation attachment to cut concrete roofing tiles. The study was conducted to determine whether the local exhaust ventilation attachment was able to control respirable dust and respirable silica exposure below occupational exposure limits. Time-integrated filter samples and direct reading respirable dust concentrations were evaluated. The local exhaust ventilation consisted of a shroud attached to the cutting plane of the saw; the shroud was then connected to a small electric axial fan, which is intended to collect dust at the point of generation. All sampling was conducted with the control in use. Roofers are defined as those individuals who solely lay tiles. Cutters/roofers are defined as those workers who operate the powered saw to cut tiles and also lay tiles. Respirable dust from this evaluation ranged from 0.13 to 6.59 milligrams per cubic meter (mg/m3) with a geometric mean of 0.38 mg/m3 for roofers and from 0.45 to 3.82 mg/m3 with a geometric mean of 1.84 mg/m3 for cutters/roofers. Cutters/roofers usually handle areas close to crevices, edges, or tips of the roof whereas roofers handle areas where complete tiles can be placed. The respirable dust exposures for all cutters/roofers indicated concentrations exceeding the Occupational Safety and Health Administration’s (OSHA) permissible exposure limit (PEL) for respirable dust containing silica; it was also exceeded for some of the roofers. The respirable silica concentrations ranged from 0.04 to 0.15 mg/m3 with an average of 0.09 mg/m3 for roofers, and from 0.13 to 1.21 mg/m3 with an average of 0.48 mg/m3 for cutters/roofers. As with respirable dust, the respirable silica exposures to cutters/roofers were higher than the exposures for roofers. PMID:25148513

An evaluation of an aftermarket local exhaust ventilation device for suppressing respirable dust and respirable crystalline silica dust from powered saws.

PubMed

Garcia, Alberto; Jones, Erica; Echt, Alan S; Hall, Ronald M

2014-01-01

The objective of this study was to quantify the respirable dust and respirable silica exposures of roofing workers using an electric-powered circular saw with an aftermarket local exhaust ventilation attachment to cut concrete roofing tiles. The study was conducted to determine whether the local exhaust ventilation attachment was able to control respirable dust and respirable silica exposure below occupational exposure limits (OELs). Time-integrated filter samples and direct reading respirable dust concentrations were evaluated. The local exhaust ventilation consisted of a shroud attached to the cutting plane of the saw; the shroud was then connected to a small electric axial fan, which is intended to collect dust at the point of generation. All sampling was conducted with the control in use. Roofers are defined as those individuals who only lay tiles. Cutters/roofers are defined as those workers who operate the powered saw to cut tiles and also lay tiles. Respirable dust from this evaluation ranged from 0.13 to 6.59 milligrams per cubic meter (mg/m(3)) with a geometric mean of 0.38 mg/m(3) for roofers and from 0.45 to 3.82 mg/m(3) with a geometric mean of 1.84 mg/m(3) for cutters/roofers. Cutters/roofers usually handle areas close to crevices, edges, or tips of the roof whereas roofers handle areas where complete tiles can be placed. The respirable dust exposures for all cutters/roofers indicated concentrations exceeding the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) for respirable dust containing silica; it was also exceeded for some of the roofers. The respirable silica concentrations ranged from 0.04 to 0.15 mg/m(3) with a geometric mean of 0.09 mg/m(3) for roofers, and from 0.13 to 1.21 mg/m(3) with a geometric mean of 0.48 mg/m(3) for cutters/roofers. As with respirable dust, the respirable silica exposures for cutters/roofers were higher than the exposures for roofers.

Improving respiration measurements with gas exchange analyzers.

PubMed

Montero, R; Ribas-Carbó, M; Del Saz, N F; El Aou-Ouad, H; Berry, J A; Flexas, J; Bota, J

2016-12-01

Dark respiration measurements with open-flow gas exchange analyzers are often questioned for their low accuracy as their low values often reach the precision limit of the instrument. Respiration was measured in five species, two hypostomatous (Vitis Vinifera L. and Acanthus mollis) and three amphistomatous, one with similar amount of stomata in both sides (Eucalyptus citriodora) and two with different stomata density (Brassica oleracea and Vicia faba). CO 2 differential (ΔCO 2 ) increased two-fold with no change in apparent R d , when the two leaves with higher stomatal density faced outside. These results showed a clear effect of the position of stomata on ΔCO 2 . Therefore, it can be concluded that leaf position is important to guarantee the improvement of respiration measurements increasing ΔCO 2 without affecting the respiration results by leaf or mass units. This method will help to increase the accuracy of leaf respiration measurements using gas exchange analyzers. Copyright © 2016 Elsevier GmbH. All rights reserved.

Field programmable gate arrays: Evaluation report for space-flight application

NASA Technical Reports Server (NTRS)

Sandoe, Mike; Davarpanah, Mike; Soliman, Kamal; Suszko, Steven; Mackey, Susan

1992-01-01

Field Programmable Gate Arrays commonly called FPGA's are the newer generation of field programmable devices and offer more flexibility in the logic modules they incorporate and in how they are interconnected. The flexibility, the number of logic building blocks available, and the high gate densities achievable are why users find FPGA's attractive. These attributes are important in reducing product development costs and shortening the development cycle. The aerospace community is interested in incorporating this new generation of field programmable technology in space applications. To this end, a consortium was formed to evaluate the quality, reliability, and radiation performance of FPGA's. This report presents the test results on FPGA parts provided by ACTEL Corporation.

Quantifying soil respiration at landscape scales. Chapter 11

Treesearch

John B. Bradford; Michael G. Ryan

2008-01-01

Soil CO2, efflux, or soil respiration, represents a substantial component of carbon cycling in terrestrial ecosystems. Consequently, quantifying soil respiration over large areas and long time periods is an increasingly important goal. However, soil respiration rates vary dramatically in space and time in response to both environmental conditions...

Photosynthesis and Respiration in a Jar.

ERIC Educational Resources Information Center

Buttner, Joseph K.

2000-01-01

Describes an activity that reduces the biosphere to a water-filled jar to simulate the relationship between cellular respiration, photosynthesis, and energy. Allows students in high school biology and related courses to explore quantitatively cellular respiration and photosynthesis in almost any laboratory setting. (ASK)

Not so hot: Rapid recovery of soil temperature and respiration following tornado damage, regardless of disturbance severity

NASA Astrophysics Data System (ADS)

Nagendra, U.; Peterson, C.

2013-12-01

Forest disturbances such as tornadoes are expected to raise soil temperatures and increase soil respiration. Opening canopy gaps allows solar radiation to heat the forest floor, and damaged plant roots provide fuel for decomposition. Patches of disturbed forest can range from low severity (some defoliation, broken branches) to high severity (uprooted or snapped trees). Disturbance severity affects plant population and community processes, such as regeneration mode, species diversity, and community structure. We expect disturbance severity to also affect ecosystem processes such as soil respiration. Severe disturbances cause more distinct, and often larger, canopy gaps than mild disturbances, and damage more standing biomass, both above- and below-ground. We would expect these larger gaps and greater litter amounts to increase soil temperature and respiration in more severely disturbed forest patches. In April 2011, a moderate (EF-3) tornado damaged portions of the Chattahoochee National Forest in NE Georgia, USA. Our lab has been characterizing the damage and regeneration in sections of the forest since summer 2011. In Spring 2013, we installed 4 iButton temperature sensors in each of 14 plots across a range of disturbance severity (for a total of 56 sensors). Severity was determined by percent of initial tree basal area downed by the tornado, and ranged from 8% to 100% basal area down. The iButtons monitored soil temperature at a depth of 5 cm every hour for 85 days. In July 2013, integrated 24-hour soil respiration was measured at the same locations using soda lime absorption in sealed PVC collars. Soil temperature at 5 cm averaged 12.66 °C. Contrary to expectations, average daily temperatures did not increase with greater plot damage severity (R2 = 0.001). Daily variation was only slightly higher in plots of very high severity. Overall, soil temperatures appeared to have returned to pre-disturbance temperatures more quickly than expected. Results for upcoming

High resolution radiometric measurements of convective storms during the GATE experiment

NASA Technical Reports Server (NTRS)

Fowler, G.; Lisa, A. S.

1976-01-01

Using passive microwave data from the NASA CV-990 aircraft and radar data collected during the Global Atmospheric Research Program Atlantic Tropical Experiment (GATE), an empirical model was developed relating brightness temperatures sensed at 19.35 GHz to surface rainfall rates. This model agreed well with theoretical computations of the relationship between microwave radiation and precipitation in the tropics. The GATE aircraft microwave data was then used to determine the detailed structure of convective systems. The high spatial resolution of the data permitted identification of individual cells which retained unique identities throughout their lifetimes in larger cloud masses and allowed analysis of the effects of cloud merger.

Optical NAND gate

DOEpatents

Skogen, Erik J [Albuquerque, NM; Raring, James [Goleta, CA; Tauke-Pedretti, Anna [Albuquerque, NM

2011-08-09

An optical NAND gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator and a photodetector. One pair of the optical waveguide devices is electrically connected in parallel to operate as an optical AND gate; and the other pair of the optical waveguide devices is connected in series to operate as an optical NOT gate (i.e. an optical inverter). The optical NAND gate utilizes two digital optical inputs and a continuous light input to provide a NAND function output. The optical NAND gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

Two CMOS gate arrays for the EPACT experiment

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

Winkert, G.

1992-08-01

Two semicustom CMOS digital gate arrays are described in this paper which have been developed for the Energetic Particles: Acceleration, Composition, and Transport (EPACT) experiment. The first device, the 'Event Counters: 16 by 24-bit' (EC1624), implements sixteen 24-bit ripple counters and has flexible counting and readout options. The second device, the 'Serial Transmitter/Receiver' (SXR), is a multi-personality chip that can be used at either end of a serial, synchronous communications data link. It can be configured as a master in a central control unit, or as one of many slaves within remote assemblies. Together a network of SXRs allows formore » commanding and verification of distributed control signals. Both gate arrays are radiation hardened and qualified for space flight use. The architecture of each chip is presented and the benefits to the experiment summarized.« less

Antibiotic efficacy is linked to bacterial cellular respiration

PubMed Central

Lobritz, Michael A.; Belenky, Peter; Porter, Caroline B. M.; Gutierrez, Arnaud; Yang, Jason H.; Schwarz, Eric G.; Dwyer, Daniel J.; Khalil, Ahmad S.; Collins, James J.

2015-01-01

Bacteriostatic and bactericidal antibiotic treatments result in two fundamentally different phenotypic outcomes—the inhibition of bacterial growth or, alternatively, cell death. Most antibiotics inhibit processes that are major consumers of cellular energy output, suggesting that antibiotic treatment may have important downstream consequences on bacterial metabolism. We hypothesized that the specific metabolic effects of bacteriostatic and bactericidal antibiotics contribute to their overall efficacy. We leveraged the opposing phenotypes of bacteriostatic and bactericidal drugs in combination to investigate their activity. Growth inhibition from bacteriostatic antibiotics was associated with suppressed cellular respiration whereas cell death from most bactericidal antibiotics was associated with accelerated respiration. In combination, suppression of cellular respiration by the bacteriostatic antibiotic was the dominant effect, blocking bactericidal killing. Global metabolic profiling of bacteriostatic antibiotic treatment revealed that accumulation of metabolites involved in specific drug target activity was linked to the buildup of energy metabolites that feed the electron transport chain. Inhibition of cellular respiration by knockout of the cytochrome oxidases was sufficient to attenuate bactericidal lethality whereas acceleration of basal respiration by genetically uncoupling ATP synthesis from electron transport resulted in potentiation of the killing effect of bactericidal antibiotics. This work identifies a link between antibiotic-induced cellular respiration and bactericidal lethality and demonstrates that bactericidal activity can be arrested by attenuated respiration and potentiated by accelerated respiration. Our data collectively show that antibiotics perturb the metabolic state of bacteria and that the metabolic state of bacteria impacts antibiotic efficacy. PMID:26100898

Radiation sensors based on the generation of mobile protons in organic dielectrics.

PubMed

Kapetanakis, Eleftherios; Douvas, Antonios M; Argitis, Panagiotis; Normand, Pascal

2013-06-26

A sensing scheme based on mobile protons generated by radiation, including ionizing radiation (IonR), in organic gate dielectrics is investigated for the development of metal-insulator-semiconductor (MIS)-type dosimeters. Application of an electric field to the gate dielectric moves the protons and thereby alters the flat band voltage (VFB) of the MIS device. The shift in the VFB is proportional to the IonR-generated protons and, therefore, to the IonR total dose. Triphenylsulfonium nonaflate (TPSNF) photoacid generator (PAG)-containing poly(methyl methacrylate) (PMMA) polymeric films was selected as radiation-sensitive gate dielectrics. The effects of UV (249 nm) and gamma (Co-60) irradiations on the high-frequency capacitance versus the gate voltage (C-VG) curves of the MIS devices were investigated for different total dose values. Systematic improvements in sensitivity can be accomplished by increasing the concentration of the TPSNF molecules embedded in the polymeric matrix.

Radiation hardening of gated x-ray imagers for the National Ignition Facility (invited).

PubMed

Bell, P M; Bradley, D K; Kilkenny, J D; Conder, A; Cerjan, C; Hagmann, C; Hey, D; Izumi, N; Moody, J; Teruya, A; Celeste, J; Kimbrough, J; Khater, H; Eckart, M J; Ayers, J

2010-10-01

The National Ignition Facility will soon be producing x-ray flux and neutron yields higher than any produced in laser driven implosion experiments in the past. Even a non-igniting capsule will require x-ray imaging of near burning plasmas at 10(17) neutrons, requiring x-ray recording systems to work in more hostile conditions than we have encountered in past laser facilities. We will present modeling, experimental data and design concepts for x-ray imaging with electronic recording systems for this environment (ARIANE). A novel instrument, active readout in a nuclear environment, is described which uses the time-of-flight difference between the gated x-ray signal and the neutron which induces a background signal to increase the yield at which gated cameras can be used.

Advanced p-MOSFET Ionizing-Radiation Dosimeter

NASA Technical Reports Server (NTRS)

Buehler, Martin G.; Blaes, Brent R.

1994-01-01

Circuit measures total dose of ionizing radiation in terms of shift in threshold gate voltage of doped-channel metal oxide/semiconductor field-effect transistor (p-MOSFET). Drain current set at temperature-independent point to increase accuracy in determination of radiation dose.

Patient training in respiratory-gated radiotherapy

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

Kini, Vijay R.; Vedam, Subrahmanya S.; Keall, Paul J.

2003-03-31

Respiratory gating is used to counter the effects of organ motion during radiotherapy for chest tumors. The effects of variations in patient breathing patterns during a single treatment and from day to day are unknown. We evaluated the feasibility of using patient training tools and their effect on the breathing cycle regularity and reproducibility during respiratory-gated radiotherapy. To monitor respiratory patterns, we used a component of a commercially available respiratory-gated radiotherapy system (Real Time Position Management (RPM) System, Varian Oncology Systems, Palo Alto, CA 94304). This passive marker video tracking system consists of reflective markers placed on the patient's chestmore » or abdomen, which are detected by a wall-mounted video camera. Software installed on a PC interfaced to this camera detects the marker motion digitally and records it. The marker position as a function of time serves as the motion signal that may be used to trigger imaging or treatment. The training tools used were audio prompting and visual feedback, with free breathing as a control. The audio prompting method used instructions to 'breathe in' or 'breathe out' at periodic intervals deduced from patients' own breathing patterns. In the visual feedback method, patients were shown a real-time trace of their abdominal wall motion due to breathing. Using this, they were asked to maintain a constant amplitude of motion. Motion traces of the abdominal wall were recorded for each patient for various maneuvers. Free breathing showed a variable amplitude and frequency. Audio prompting resulted in a reproducible frequency; however, the variability and the magnitude of amplitude increased. Visual feedback gave a better control over the amplitude but showed minor variations in frequency. We concluded that training improves the reproducibility of amplitude and frequency of patient breathing cycles. This may increase the accuracy of respiratory-gated radiation therapy.« less

Transparently wrap-gated semiconductor nanowire arrays for studies of gate-controlled photoluminescence

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

Nylund, Gustav; Storm, Kristian; Torstensson, Henrik

2013-12-04

We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure.

Dual-Gate p-GaN Gate High Electron Mobility Transistors for Steep Subthreshold Slope.

PubMed

Bae, Jong-Ho; Lee, Jong-Ho

2016-05-01

A steep subthreshold slope characteristic is achieved through p-GaN gate HEMT with dual-gate structure. Obtained subthreshold slope is less than 120 μV/dec. Based on the measured and simulated data obtained from single-gate device, breakdown of parasitic floating-base bipolar transistor and floating gate charged with holes are responsible to increase abruptly in drain current. In the dual-gate device, on-current degrades with high temperature but subthreshold slope is not changed. To observe the switching speed of dual-gate device and transient response of drain current are measured. According to the transient responses of drain current, switching speed of the dual-gate device is about 10(-5) sec.

Peruvian upwelling plankton respiration: calculations of carbon flux, nutrient retention efficiency, and heterotrophic energy production

NASA Astrophysics Data System (ADS)

Packard, T. T.; Osma, N.; Fernández-Urruzola, I.; Codispoti, L. A.; Christensen, J. P.; Gómez, M.

2015-05-01

Oceanic depth profiles of plankton respiration are described by a power function, RCO2 = (RCO2)0 (z/z0)b, similar to the vertical carbon flux profile. Furthermore, because both ocean processes are closely related, conceptually and mathematically, each can be calculated from the other. The exponent b, always negative, defines the maximum curvature of the respiration-depth profile and controls the carbon flux. When |b| is large, the carbon flux (FC) from the epipelagic ocean is low and the nutrient retention efficiency (NRE) is high, allowing these waters to maintain high productivity. The opposite occurs when |b| is small. This means that the attenuation of respiration in ocean water columns is critical in understanding and predicting both vertical FC as well as the capacity of epipelagic ecosystems to retain their nutrients. The ratio of seawater RCO2 to incoming FC is the NRE, a new metric that represents nutrient regeneration in a seawater layer in reference to the nutrients introduced into that layer via FC. A depth profile of FC is the integral of water column respiration. This relationship facilitates calculating ocean sections of FC from water column respiration. In an FC section and in a NRE section across the Peruvian upwelling system we found an FC maximum and a NRE minimum extending down to 400 m, 50 km off the Peruvian coast over the upper part of the continental slope. Finally, considering the coupling between respiratory electron transport system activity and heterotrophic oxidative phosphorylation promoted the calculation of an ocean section of heterotrophic energy production (HEP). It ranged from 250 to 500 J d-1 m-3 in the euphotic zone to less than 5 J d-1 m-3 below 200 m on this ocean section.

Reverse engineering model structures for soil and ecosystem respiration: the potential of gene expression programming

NASA Astrophysics Data System (ADS)

Ilie, Iulia; Dittrich, Peter; Carvalhais, Nuno; Jung, Martin; Heinemeyer, Andreas; Migliavacca, Mirco; Morison, James I. L.; Sippel, Sebastian; Subke, Jens-Arne; Wilkinson, Matthew; Mahecha, Miguel D.

2017-09-01

Accurate model representation of land-atmosphere carbon fluxes is essential for climate projections. However, the exact responses of carbon cycle processes to climatic drivers often remain uncertain. Presently, knowledge derived from experiments, complemented by a steadily evolving body of mechanistic theory, provides the main basis for developing such models. The strongly increasing availability of measurements may facilitate new ways of identifying suitable model structures using machine learning. Here, we explore the potential of gene expression programming (GEP) to derive relevant model formulations based solely on the signals present in data by automatically applying various mathematical transformations to potential predictors and repeatedly evolving the resulting model structures. In contrast to most other machine learning regression techniques, the GEP approach generates readable models that allow for prediction and possibly for interpretation. Our study is based on two cases: artificially generated data and real observations. Simulations based on artificial data show that GEP is successful in identifying prescribed functions, with the prediction capacity of the models comparable to four state-of-the-art machine learning methods (random forests, support vector machines, artificial neural networks, and kernel ridge regressions). Based on real observations we explore the responses of the different components of terrestrial respiration at an oak forest in south-eastern England. We find that the GEP-retrieved models are often better in prediction than some established respiration models. Based on their structures, we find previously unconsidered exponential dependencies of respiration on seasonal ecosystem carbon assimilation and water dynamics. We noticed that the GEP models are only partly portable across respiration components, the identification of a general terrestrial respiration model possibly prevented by equifinality issues. Overall, GEP

Nutrients and temperature additively increase stream microbial respiration

Treesearch

David W. P. Manning; Amy D. Rosemond; Vladislav Gulis; Jonathan P. Benstead; John S. Kominoski

2017-01-01

Rising temperatures and nutrient enrichment are co‐occurring global‐change drivers that stimulate microbial respiration of detrital carbon, but nutrient effects on the temperature dependence of respiration in aquatic ecosystems remain uncertain. We measured respiration rates associated with leaf litter, wood, and fine benthic organic matter (FBOM) across...

Single-Frequency Ultrasound-Based Respiration Rate Estimation with Smartphones.

PubMed

Ge, Linfei; Zhang, Jin; Wei, Jing

2018-01-01

Respiration monitoring is helpful in disease prevention and diagnosis. Traditional respiration monitoring requires users to wear devices on their bodies, which is inconvenient for them. In this paper, we aim to design a noncontact respiration rate detection system utilizing off-the-shelf smartphones. We utilize the single-frequency ultrasound as the media to detect the respiration activity. By analyzing the ultrasound signals received by the built-in microphone sensor in a smartphone, our system can derive the respiration rate of the user. The advantage of our method is that the transmitted signal is easy to generate and the signal analysis is simple, which has lower power consumption and thus is suitable for long-term monitoring in daily life. The experimental result shows that our system can achieve accurate respiration rate estimation under various scenarios.

Integration of CO2 flux and remotely-sensed data for primary production and ecosystem respiration analyses in the Northern Great Plains: potential for quantitative spatial extrapolation

USGS Publications Warehouse

Gilmanov, Tagir G.; Tieszen, Larry L.; Wylie, Bruce K.; Flanagan, Larry B.; Frank, Albert B.; Haferkamp, Marshall R.; Meyers, Tilden P.; Morgan, Jack A.

2005-01-01

Aim  Extrapolation of tower CO2 fluxes will be greatly facilitated if robust relationships between flux components and remotely sensed factors are established. Long-term measurements at five Northern Great Plains locations were used to obtain relationships between CO2fluxes and photosynthetically active radiation (Q), other on-site factors, and Normalized Difference Vegetation Index (NDVI) from the SPOT VEGETATION data set. Location  CO2 flux data from the following stations and years were analysed: Lethbridge, Alberta 1998–2001; Fort Peck, MT 2000, 2002; Miles City, MT 2000–01; Mandan, ND 1999–2001; and Cheyenne, WY 1997–98. Results  Analyses based on light-response functions allowed partitioning net CO2 flux (F) into gross primary productivity (Pg) and ecosystem respiration (Re). Weekly averages of daytime respiration, γday, estimated from light responses were closely correlated with weekly averages of measured night-time respiration, γnight (R2 0.64 to 0.95). Daytime respiration tended to be higher than night-time respiration, and regressions of γday on γnight for all sites were different from 1 : 1 relationships. Over 13 site-years, gross primary production varied from 459 to 2491 g CO2 m−2 year−1, ecosystem respiration from 996 to 1881 g CO2 m−2 year−1, and net ecosystem exchange from −537 (source) to +610 g CO2 m−2 year−1 (sink). Maximum daily ecological light-use efficiencies, ɛd,max = Pg/Q, were in the range 0.014 to 0.032 mol CO2 (mol incident quanta)−1. Main conclusions  Ten-day average Pg was significantly more highly correlated with NDVI than 10-day average daytime flux, Pd (R2 = 0.46 to 0.77 for Pg-NDVI and 0.05 to 0.58 for Pd-NDVI relationships). Ten-day average Re was also positively correlated with NDVI, with R2values from 0.57 to 0.77. Patterns of the relationships of Pg and Re with NDVI and other factors indicate possibilities for establishing multivariate

Transient elevation of glycolysis confers radio-resistance by facilitating DNA repair in cells.

PubMed

Bhatt, Anant Narayan; Chauhan, Ankit; Khanna, Suchit; Rai, Yogesh; Singh, Saurabh; Soni, Ravi; Kalra, Namita; Dwarakanath, Bilikere S

2015-05-01

Cancer cells exhibit increased glycolysis for ATP production (the Warburg effect) and macromolecular biosynthesis; it is also linked with therapeutic resistance that is generally associated with compromised respiratory metabolism. Molecular mechanisms underlying radio-resistance linked to elevated glycolysis remain incompletely understood. We stimulated glycolysis using mitochondrial respiratory modifiers (MRMs viz. di-nitro phenol, DNP; Photosan-3, PS3; Methylene blue, MB) in established human cell lines (HEK293, BMG-1 and OCT-1). Glucose utilization and lactate production, levels of glucose transporters and glycolytic enzymes were investigated as indices of glycolysis. Clonogenic survival, DNA repair and cytogenetic damage were studied as parameters of radiation response. MRMs induced the glycolysis by enhancing the levels of two important regulators of glucose metabolism GLUT-1 and HK-II and resulted in 2 fold increase in glucose consumption and lactate production. This increase in glycolysis resulted in resistance against radiation-induced cell death (clonogenic survival) in different cell lines at an absorbed dose of 5 Gy. Inhibition of glucose uptake and glycolysis (using fasentin, 2-deoxy-D-glucose and 3-bromopyruvate) in DNP treated cells failed to increase the clonogenic survival of irradiated cells, suggesting that radio-resistance linked to inhibition of mitochondrial respiration is glycolysis dependent. Elevated glycolysis also facilitated rejoining of radiation-induced DNA strand breaks by activating both non-homologous end joining (NHEJ) and homologous recombination (HR) pathways of DNA double strand break repair leading to a reduction in radiation-induced cytogenetic damage (micronuclei formation) in these cells. These findings suggest that enhanced glycolysis generally observed in cancer cells may be responsible for the radio-resistance, partly by enhancing the repair of DNA damage.

Top-gate pentacene-based organic field-effect transistor with amorphous rubrene gate insulator

NASA Astrophysics Data System (ADS)

Hiroki, Mizuha; Maeda, Yasutaka; Ohmi, Shun-ichiro

2018-02-01

The scaling of organic field-effect transistors (OFETs) is necessary for high-density integration and for this, OFETs with a top-gate configuration are required. There have been several reports of damageless lithography processes for organic semiconductor or insulator layers. However, it is still difficult to fabricate scaled OFETs with a top-gate configuration. In this study, the lift-off process and the device characteristics of the OFETs with a top-gate configuration utilizing an amorphous (α) rubrene gate insulator were investigated. We have confirmed that α-rubrene shows an insulating property, and its extracted linear mobility was 2.5 × 10-2 cm2/(V·s). The gate length and width were 10 and 60 µm, respectively. From these results, the OFET with a top-gate configuration utilizing an α-rubrene gate insulator is promising for the high-density integration of scaled OFETs.

Eye tracking and gating system for proton therapy of orbital tumors

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

Shin, Dongho; Yoo, Seung Hoon; Moon, Sung Ho

2012-07-15

Purpose: A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. Methods: We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To measure the pixel spacing of an image consistently, four different calibration modes such as the point-detection, the edge-detection, the line-measurement, and the manual measurement mode were suggested and used. After these methods were applied to proton therapy, gating was performed, and radiation dose distributions were evaluated. Results: Moving phantom verification measurements resulted in errorsmore » of less than 0.1 mm for given ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure. The analysis from clinical results suggests that the average of eye movements depends distinctively on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively. Conclusions: The developed automatic eye-tracking based beam-gating system enabled us to perform high-precision proton radiotherapy of orbital tumors.« less

42 CFR 84.253 - Chemical-cartridge respirators; requirements and tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical-cartridge respirators; requirements and... DEVICES Special Use Respirators § 84.253 Chemical-cartridge respirators; requirements and tests. (a... for chemical-cartridge respirators prescribed in Subpart L of this part are applicable to replaceable...

42 CFR 84.253 - Chemical-cartridge respirators; requirements and tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical-cartridge respirators; requirements and... DEVICES Special Use Respirators § 84.253 Chemical-cartridge respirators; requirements and tests. (a... for chemical-cartridge respirators prescribed in Subpart L of this part are applicable to replaceable...

Global spatiotemporal distribution of soil respiration modeled using a global database

NASA Astrophysics Data System (ADS)

Hashimoto, S.; Carvalhais, N.; Ito, A.; Migliavacca, M.; Nishina, K.; Reichstein, M.

2015-07-01

The flux of carbon dioxide from the soil to the atmosphere (soil respiration) is one of the major fluxes in the global carbon cycle. At present, the accumulated field observation data cover a wide range of geographical locations and climate conditions. However, there are still large uncertainties in the magnitude and spatiotemporal variation of global soil respiration. Using a global soil respiration data set, we developed a climate-driven model of soil respiration by modifying and updating Raich's model, and the global spatiotemporal distribution of soil respiration was examined using this model. The model was applied at a spatial resolution of 0.5°and a monthly time step. Soil respiration was divided into the heterotrophic and autotrophic components of respiration using an empirical model. The estimated mean annual global soil respiration was 91 Pg C yr-1 (between 1965 and 2012; Monte Carlo 95 % confidence interval: 87-95 Pg C yr-1) and increased at the rate of 0.09 Pg C yr-2. The contribution of soil respiration from boreal regions to the total increase in global soil respiration was on the same order of magnitude as that of tropical and temperate regions, despite a lower absolute magnitude of soil respiration in boreal regions. The estimated annual global heterotrophic respiration and global autotrophic respiration were 51 and 40 Pg C yr-1, respectively. The global soil respiration responded to the increase in air temperature at the rate of 3.3 Pg C yr-1 °C-1, and Q10 = 1.4. Our study scaled up observed soil respiration values from field measurements to estimate global soil respiration and provide a data-oriented estimate of global soil respiration. The estimates are based on a semi-empirical model parameterized with over one thousand data points. Our analysis indicates that the climate controls on soil respiration may translate into an increasing trend in global soil respiration and our analysis emphasizes the relevance of the soil carbon flux from soil to

Plant growth and respiration re-visited: maintenance respiration defined – it is an emergent property of, not a separate process within, the system – and why the respiration : photosynthesis ratio is conservative

PubMed Central

Thornley, John H. M.

2011-01-01

Background and Aims Plant growth and respiration still has unresolved issues, examined here using a model. The aims of this work are to compare the model's predictions with McCree's observation-based respiration equation which led to the ‘growth respiration/maintenance respiration paradigm’ (GMRP) – this is required to give the model credibility; to clarify the nature of maintenance respiration (MR) using a model which does not represent MR explicitly; and to examine algebraic and numerical predictions for the respiration:photosynthesis ratio. Methods A two-state variable growth model is constructed, with structure and substrate, applicable on plant to ecosystem scales. Four processes are represented: photosynthesis, growth with growth respiration (GR), senescence giving a flux towards litter, and a recycling of some of this flux. There are four significant parameters: growth efficiency, rate constants for substrate utilization and structure senescence, and fraction of structure returned to the substrate pool. Key Results The model can simulate McCree's data on respiration, providing an alternative interpretation to the GMRP. The model's parameters are related to parameters used in this paradigm. MR is defined and calculated in terms of the model's parameters in two ways: first during exponential growth at zero growth rate; and secondly at equilibrium. The approaches concur. The equilibrium respiration:photosynthesis ratio has the value of 0·4, depending only on growth efficiency and recycling fraction. Conclusions McCree's equation is an approximation that the model can describe; it is mistaken to interpret his second coefficient as a maintenance requirement. An MR rate is defined and extracted algebraically from the model. MR as a specific process is not required and may be replaced with an approach from which an MR rate emerges. The model suggests that the respiration:photosynthesis ratio is conservative because it depends on two parameters only whose

Terahertz amplification in RTD-gated HEMTs with a grating-gate wave coupling topology

NASA Astrophysics Data System (ADS)

Condori Quispe, Hugo O.; Encomendero-Risco, Jimy J.; Xing, Huili Grace; Sensale-Rodriguez, Berardi

2016-08-01

We theoretically analyze the operation of a terahertz amplifier consisting of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT) in a grating-gate topology. In these devices, the key element enabling substantial power gain is the efficient coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e., the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as discussed in previous works, therefore potentially enabling terahertz amplification with associated power gains >40 dB.

The effect of UV-B radiation on photosynthesis and respiration of phytoplankton, benthic macroalgae and seagrasses.

PubMed

Larkum, A W; Wood, W F

1993-04-01

Several species of marine benthic algae, four species of phytoplankton and two species of seagrass have been subjected to ultraviolet B irradiation for varying lengths of time and the effects on respiration, photosynthesis and fluorescence rise kinetics studied. No effect on respiration was found. Photosynthesis was inhibited to a variable degree in all groups of plants after irradiation over periods of up to 1 h and variable fluorescence was also inhibited in a similar way. The most sensitive plants were phytoplankton and deep-water benthic algae. Intertidal benthic algae were the least sensitive to UV-B irradiation and this may be related to adaptation, through the accumulation of UV-B screening compounds, to high light/high UV-B levels. Inhibition of variable fluorescence (Fv) of the fluorescence rise curve was a fast and sensitive indicator of UV-B damage. Two plants studied, a brown alga and a seagrass, showed very poor recovery of Fv over a period of 32 h.

Thawing permafrost increases old soil and autotrophic respiration in tundra: partitioning ecosystem respiration using δ(13) C and ∆(14) C.

PubMed

Hicks Pries, Caitlin E; Schuur, Edward A G; Crummer, Kathryn G

2013-02-01

Ecosystem respiration (Reco ) is one of the largest terrestrial carbon (C) fluxes. The effect of climate change on Reco depends on the responses of its autotrophic and heterotrophic components. How autotrophic and heterotrophic respiration sources respond to climate change is especially important in ecosystems underlain by permafrost. Permafrost ecosystems contain vast stores of soil C (1672 Pg) and are located in northern latitudes where climate change is accelerated. Warming will cause a positive feedback to climate change if heterotrophic respiration increases without corresponding increases in primary production. We quantified the response of autotrophic and heterotrophic respiration to permafrost thaw across the 2008 and 2009 growing seasons. We partitioned Reco using Δ(14) C and δ(13) C into four sources-two autotrophic (above - and belowground plant structures) and two heterotrophic (young and old soil). We sampled the Δ(14) C and δ(13) C of sources using incubations and the Δ(14) C and δ(13) C of Reco using field measurements. We then used a Bayesian mixing model to solve for the most likely contributions of each source to Reco . Autotrophic respiration ranged from 40 to 70% of Reco and was greatest at the height of the growing season. Old soil heterotrophic respiration ranged from 6 to 18% of Reco and was greatest where permafrost thaw was deepest. Overall, growing season fluxes of autotrophic and old soil heterotrophic respiration increased as permafrost thaw deepened. Areas with greater thaw also had the greatest primary production. Warming in permafrost ecosystems therefore leads to increased plant and old soil respiration that is initially compensated by increased net primary productivity. However, barring large shifts in plant community composition, future increases in old soil respiration will likely outpace productivity, resulting in a positive feedback to climate change. © 2012 Blackwell Publishing Ltd.

[The development of a respiration and temperature monitor].

PubMed

Du, X; Wu, B; Liu, Y; He, Q; Xiao, J

2001-12-01

This paper introduces the design of a monitoring system to measure the respiration and temperature of a body with an 8Xc196 single-chip microcomputer. This system can measure and display the respiration wave, respiration frequency and the body temperature in real-time with a liquid crystal display (LCD) and give an alarm when the parameters are beyond the normal scope. In addition, this device can provide a 24 hours trend graph of the respiration frequency and the body temperature parameters measured. Data can also be exchanged through serial communication interfaces (RS232) between the PC and the monitor.

Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

PubMed Central

Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

2015-01-01

Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (R A) and heterotrophic (R H) in total soil (R T) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.–Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of R H and R A to R T for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to R T, accounted for over 63% of R H. 3) AT and ST were significantly positively correlated with R T and its components (p<0.05), and were major factors affecting soil respiration. 4) Components of soil respiration were significantly different between two forest stands (p<0.05), indicating that vegetation types played a role in soil respiration and its components. PMID:25680112

Single-Frequency Ultrasound-Based Respiration Rate Estimation with Smartphones

PubMed Central

Wei, Jing

2018-01-01

Respiration monitoring is helpful in disease prevention and diagnosis. Traditional respiration monitoring requires users to wear devices on their bodies, which is inconvenient for them. In this paper, we aim to design a noncontact respiration rate detection system utilizing off-the-shelf smartphones. We utilize the single-frequency ultrasound as the media to detect the respiration activity. By analyzing the ultrasound signals received by the built-in microphone sensor in a smartphone, our system can derive the respiration rate of the user. The advantage of our method is that the transmitted signal is easy to generate and the signal analysis is simple, which has lower power consumption and thus is suitable for long-term monitoring in daily life. The experimental result shows that our system can achieve accurate respiration rate estimation under various scenarios. PMID:29853985

A STUDY OF THE EFFECT OF GAMMA RADIATION ON APPLES

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

Smock, R.M.; Sparrow, A.H.

1957-01-01

Gamma radiation (cobalt source) of Rhode Island Greening apples did not lower the respiration rate. The 40,000 r lot had a higher than normal rate. This lot also softened more during the holding period at.74 deg F. Dosages over 10,000 r seemed to aggravate mealy breakdown. Dosages of 20,000 amd 40,000 r reduced the production of ethylene and volatiles other than ethylene. The respiration rate of Cortland apples was reduced slightly by gamma radiation. Keeping quality of this variety in storage was not affected, except for the 30,000 r lot which was slightly softer. Weight losses were not affected bymore » radiation. No commercially important benefits were observed with either variety. (auth)« less

3. VIEW OF MECHANICAL GATE LIFTING MECHANISM (MULE) AND GATE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW OF MECHANICAL GATE LIFTING MECHANISM (MULE) AND GATE RACKS, LOOKING EAST - Nine Mile Hydroelectric Development, Powerhouse, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

Velocity-amplified microbial respiration rates in the lower Amazon River: Amazon River respiration

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

Ward, Nicholas D.; Sawakuchi, Henrique O.; Neu, Vania

Most measurements of respiration rates in large tropical rivers do not account for the influence of river flow conditions on microbial activity. We developed a ship-board spinning incubation system for measuring O2 drawdown under different rotation velocities and deployed the system along the lower Amazon River during four hydrologic periods. Average respiration rates in incubation chambers rotated at 0.22 and 0.66 m s-1 were 1.4 and 2.4 times higher than stationary chambers, respectively. On average, depth-integrated respiration rates in chambers spun at 0.22 and 0.66 m s-1 accounted for 64 ± 22% and 104 ± 36% of CO2 outgassing rates,more » respectively, in mainstem sites. Continuous measurements of in situ pCO2 were also made along with cross-channel profiles of river velocity. A positive correlation between river velocity and pCO2 was observed along the lower river (r2=0.67-0.96) and throughout a tidal cycle.« less

Respiration from the organ level to the stand

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

Sprugel, D.G.; Ryan, M.G.; Brooks, J.R.

1995-07-01

The status of efforts to estimate respiration of conifers varies sharply from one tissue to another. There have been numerous measurements of foliage respiration in conifers, but relatively few measurements of within-stand variation in reference to parameters that might be used for scaling. However, a number of logical models for scaling have been proposed (e.g., light, age, or N) and general directions for future research seem well established. There are far fewer measurements of woody-tissue respiration that might be useful for scaling, but some consensus seems to have developed that the use of sapwood biomass and growth rates as indicesmore » may provide the key to scaling woody-tissue respiration up to the stand level. Root respiration is still bogged down by a plurality of methods, each of which seems to have some serious disadvantages, so that even the nature of within-stand variation is poorly known. Successful and believable scaling of root respiration from tissue-specific measurements to the stand level seems to be far in the future. Finally, proxy measurements such as litterfall and N concentration can and have been used to estimate respiration for whole stands without measuring tissue-specific rates at all, but all of these techniques require assumptions that need further testing before they will be generally accepted.« less

Quantum information processing with long-wavelength radiation

NASA Astrophysics Data System (ADS)

Murgia, David; Weidt, Sebastian; Randall, Joseph; Lekitsch, Bjoern; Webster, Simon; Navickas, Tomas; Grounds, Anton; Rodriguez, Andrea; Webb, Anna; Standing, Eamon; Pearce, Stuart; Sari, Ibrahim; Kiang, Kian; Rattanasonti, Hwanjit; Kraft, Michael; Hensinger, Winfried

To this point, the entanglement of ions has predominantly been performed using lasers. Using long wavelength radiation with static magnetic field gradients provides an architecture to simplify construction of a large scale quantum computer. The use of microwave-dressed states protects against decoherence from fluctuating magnetic fields, with radio-frequency fields used for qubit manipulation. I will report the realisation of spin-motion entanglement using long-wavelength radiation, and a new method to efficiently prepare dressed-state qubits and qutrits, reducing experimental complexity of gate operations. I will also report demonstration of ground state cooling using long wavelength radiation, which may increase two-qubit entanglement fidelity. I will then report demonstration of a high-fidelity long-wavelength two-ion quantum gate using dressed states. Combining these results with microfabricated ion traps allows for scaling towards a large scale ion trap quantum computer, and provides a platform for quantum simulations of fundamental physics. I will report progress towards the operation of microchip ion traps with extremely high magnetic field gradients for multi-ion quantum gates.

2. VIEW OF MECHANICAL GATE LIFTING MECHANISM (MULE) AND GATE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VIEW OF MECHANICAL GATE LIFTING MECHANISM (MULE) AND GATE LIFTING RACKS, LOOKING WEST - Nine Mile Hydroelectric Development, Powerhouse, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

Terahertz amplification in RTD-gated HEMTs with a grating-gate wave coupling topology

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

Condori Quispe, Hugo O.; Sensale-Rodriguez, Berardi; Encomendero-Risco, Jimy J.

2016-08-08

We theoretically analyze the operation of a terahertz amplifier consisting of a resonant-tunneling-diode gated high-electron-mobility transistor (RTD-gated HEMT) in a grating-gate topology. In these devices, the key element enabling substantial power gain is the efficient coupling of terahertz waves into and out of plasmons in the RTD-gated HEMT channel, i.e., the gain medium, via the grating-gate itself, part of the active device, rather than by an external antenna structure as discussed in previous works, therefore potentially enabling terahertz amplification with associated power gains >40 dB.

Low-power DRAM-compatible Replacement Gate High-k/Metal Gate Stacks

NASA Astrophysics Data System (ADS)

Ritzenthaler, R.; Schram, T.; Bury, E.; Spessot, A.; Caillat, C.; Srividya, V.; Sebaai, F.; Mitard, J.; Ragnarsson, L.-Å.; Groeseneken, G.; Horiguchi, N.; Fazan, P.; Thean, A.

2013-06-01

In this work, the possibility of integration of High-k/Metal Gate (HKMG), Replacement Metal Gate (RMG) gate stacks for low power DRAM compatible transistors is studied. First, it is shown that RMG gate stacks used for Logic applications need to be seriously reconsidered, because of the additional anneal(s) needed in a DRAM process. New solutions are therefore developed. A PMOS stack HfO2/TiN with TiN deposited in three times combined with Work Function metal oxidations is demonstrated, featuring a very good Work Function of 4.95 eV. On the other hand, the NMOS side is shown to be a thornier problem to solve: a new solution based on the use of oxidized Ta as a diffusion barrier is proposed, and a HfO2/TiN/TaOX/TiAl/TiN/TiN gate stack featuring an aggressive Work Function of 4.35 eV (allowing a Work Function separation of 600 mV between NMOS and PMOS) is demonstrated. This work paves the way toward the integration of gate-last options for DRAM periphery transistors.

Respirable dust measured downwind during rock dust application.

PubMed

Harris, M L; Organiscak, J; Klima, S; Perera, I E

2017-05-01

The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

Radiation-induced cardiomyopathy as a function of radiation beam gating to the cardiac cycle

NASA Astrophysics Data System (ADS)

Gladstone, David J.; Flanagan, Michael F.; Southworth, Jean B.; Hadley, Vaughn; Thibualt, Melissa Wei; Hug, Eugen B.; Hoopes, P. Jack

2004-04-01

Portions of the heart are often unavoidably included in the primary treatment volume during thoracic radiotherapy, and radiation-induced heart disease has been observed as a treatment-related complication. Such complications have been observed in humans following radiation therapy for Hodgkin's disease and treatment of the left breast for carcinoma. Recent attempts have been made to prevent re-stenosis following angioplasty procedures using external beam irradiation. These attempts were not successful, however, due to the large volume of heart included in the treatment field and subsequent cardiac morbidity. We suggest a mechanism for sparing the heart from radiation damage by synchronizing the radiation beam with the cardiac cycle and delivering radiation only when the heart is in a relatively hypoxic state. We present data from a rat model testing this hypothesis and show that radiation damage to the heart can be altered by synchronizing the radiation beam with the cardiac cycle. This technique may be useful in reducing radiation damage to the heart secondary to treatment for diseases such as Hodgkin's disease and breast cancer.

Fault handling schemes in electronic systems with specific application to radiation tolerance and VLSI design

NASA Technical Reports Server (NTRS)

Attia, John Okyere

1993-01-01

Naturally occurring space radiation particles can produce transient and permanent changes in the electrical properties of electronic devices and systems. In this work, the transient radiation effects on DRAM and CMOS SRAM were considered. In addition, the effect of total ionizing dose radiation of the switching times of CMOS logic gates were investigated. Effects of transient radiation on the column and cell of MOS dynamic memory cell was simulated using SPICE. It was found that the critical charge of the bitline was higher than that of the cell. In addition, the critical charge of the combined cell-bitline was found to be dependent on the gate voltage of the access transistor. In addition, the effect of total ionizing dose radiation on the switching times of CMOS logic gate was obtained. The results of this work indicate that, the rise time of CMOS logic gates increases, while the fall time decreases with an increase in total ionizing dose radiation. Also, by increasing the size of the P-channel transistor with respect to that of the N-channel transistor, the propagation delay of CMOS logic gate can be made to decrease with, or be independent of an increase in total ionizing dose radiation. Furthermore, a method was developed for replacing polysilicon feedback resistance of SRAMs with a switched capacitor network. A switched capacitor SRAM was implemented using MOS Technology. The critical change of the switched capacitor SRAM has a very large critical charge. The results of this work indicate that switched capacitor SRAM is a viable alternative to SRAM with polysilicon feedback resistance.

WE-EF-303-05: Development and Commissioning of Real-Time Imaging Function for Respiratory-Gated Spot-Scanning Proton Beam Therapy

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

Miyamoto, N; Takao, S; Matsuura, T

2015-06-15

Purpose: To realize real-time-image gated proton beam therapy (RGPT) for treating mobile tumors. Methods: The rotating gantry of spot scanning proton beam therapy has been designed to equip two x-ray fluoroscopy devices that enable real-time imaging of the internal fiducial markers during respiration. Three-dimensional position of the fiducial marker located near the tumor can be calculated from the fluoroscopic images obtained from orthogonal directions and therapeutic beam is gated only when the fiducial marker is within the predefined gating window. Image acquisition rate can be selected from discrete value ranging from 0.1 Hz to 30 Hz. In order to confirmmore » the effectiveness of RGPT and apply it clinically, clinical commissioning was conducted. Commissioning tests were categorized to main three parts including geometric accuracy, temporal accuracy and dosimetric evaluation. Results: Developed real-time imaging function has been installed and its basic performances have been confirmed. In the evaluation of geometric accuracy, coincidence of three-dimensional treatment room coordinate system and imaging coordinate system was confirmed to be less than 1 mm. Fiducial markers (gold sphere and coil) were able to be tracked in simulated clinical condition using an anthropomorphic chest phantom. In the evaluation of temporal accuracy, latency from image acquisition to gate on/off signal was about 60 msec in typical case. In dosimetric evaluation, treatment beam characteristics including beam irradiation position and dose output were stable in gated irradiation. Homogeneity indices to the mobile target were 0.99 (static), 0.89 (w/o gating, motion is parallel to direction of scan), 0.75 (w/o gating, perpendicular), 0.98 (w/ gating, parallel) and 0.93 (w/ gating, perpendicular). Dose homogeneity to the mobile target can be maintained in RGPT. Conclusion: Real-time imaging function utilizing x-ray fluoroscopy has been developed and commissioned successfully in order

Constraining Night Time Ecosystem Respiration by Inverse Approaches

NASA Astrophysics Data System (ADS)

Juang, J.; Stoy, P. C.; Siqueira, M. B.; Katul, G. G.

2004-12-01

Estimating nighttime ecosystem respiration remains a key challenge in quantifying ecosystem carbon budgets. Currently, nighttime eddy-covariance (EC) flux measurements are plagued by uncertainties often attributed to poor mixing within the canopy volume, non-turbulent transport of CO2 into and out of the canopy, and non-stationarity and intermittency. Here, we explore the use of second-order closure models to estimate nighttime ecosystem respiration by mathematically linking sources of CO2 to mean concentration profiles via the continuity and the CO2 flux budget equation modified to include thermal stratification. By forcing this model to match, in a root-mean squared sense, the nighttime measured mean CO2 concentration profiles within the canopy the above ground CO2 production and forest floor respiration can be estimated via multi-dimensional optimization techniques. We show that in a maturing pine and a mature hardwood forest, these optimized CO2 sources are (1) consistently larger than the eddy covariance flux measurements above the canopy, and (2) agree well with chamber-based measurements. We also show that by linking the optimized nighttime ecosystem respiration to temperature measurements, the estimated annual ecosystem respiration from this approach agrees well with biometric estimates, at least when compared to eddy-covariance methods conditioned on a friction velocity threshold. The difference between the annual ecosystem respiration obtained by this optimization method and the friction-velocity thresholded night-time EC fluxes can be as large as 700 g C m-2 (in 2003) for the maturing pine forest, which is about 40% of the ecosystem respiration. For 2001 and 2002, the annual ecosystem respiration differences between the EC-based and the proposed approach were on the order of 300 to 400 g C m-2.

Creatine kinase and mitochondrial respiration in hearts of trout, cod and freshwater turtle.

PubMed

Birkedal, R; Gesser, H

2003-08-01

The importance of the creatine kinase system in the cardiac muscle of ectothermic vertebrates is unclear. Mammalian cardiac muscle seems to be structurally organized in a manner that compartmentalizes the intracellular environment as evidenced by the substantially higher mitochondrial apparent Km for ADP in skinned fibres compared to isolated mitochondria. A mitochondrial fraction of creatine kinase is functionally coupled to the mitochondrial respiration, and the transport of phosphocreatine and creatine as energy equivalents of ATP and ADP, respectively, increases the mitochondrial apparent ADP affinity, i.e. lowers the Km. This function of creatine kinase seems to be absent in hearts of frog species. To find out whether this applies to hearts of ectothermic vertebrate species in general, we investigated the effect of creatine on the mitochondrial respiration of saponin-skinned fibres from the ventricle of rainbow trout, Atlantic cod and freshwater turtle. For all three species, the apparent Km for ADP appeared to be substantially higher than for isolated mitochondria. Creatine lowered this Km in trout and turtle, thus indicating a functional coupling between mitochondrial creatine kinase and respiration. However, creatine had no effect on Km in cod ventricle. In conclusion, the creatine kinase-system in trout and turtle hearts seems to fulfil the same functions as in the mammalian heart, i.e. facilitating energy transport and communication between cellular compartments. In cod heart, however, this does not seem to be the case.

42 CFR 84.131 - Supplied-air respirators; required components.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Facepiece, hood, or helmet; (2) Air supply valve, orifice, or demand or pressure-demand regulator; (3) Hand... 42 Public Health 1 2010-10-01 2010-10-01 false Supplied-air respirators; required components. 84... Supplied-Air Respirators § 84.131 Supplied-air respirators; required components. (a) Each supplied-air...

Thermal adaptation of heterotrophic soil respiration in laboratory microcosms.

Treesearch

Mark A. Bradford; Brian W. Watts; Christian A. Davies

2010-01-01

Respiration of heterotrophic microorganisms decomposing soil organic carbon releases carbon dioxide from soils to the atmosphere. In the short term, soil microbial respiration is strongly dependent on temperature. In the long term, the response of heterotrophic soil respiration to temperature is uncertain. However, following established evolutionary tradeoffs, mass-...

Non-ECG-gated unenhanced MRA of the carotids: optimization and clinical feasibility.

PubMed

Raoult, H; Gauvrit, J Y; Schmitt, P; Le Couls, V; Bannier, E

2013-11-01

To optimise and assess the clinical feasibility of a carotid non-ECG-gated unenhanced MRA sequence. Sixteen healthy volunteers and 11 patients presenting with internal carotid artery (ICA) disease underwent large field-of-view balanced steady-state free precession (bSSFP) unenhanced MRA at 3T. Sampling schemes acquiring the k-space centre either early (kCE) or late (kCL) in the acquisition window were evaluated. Signal and image quality was scored in comparison to ECG-gated kCE unenhanced MRA and TOF. For patients, computed tomography angiography was used as the reference. In volunteers, kCE sampling yielded higher image quality than kCL and TOF, with fewer flow artefacts and improved signal homogeneity. kCE unenhanced MRA image quality was higher without ECG-gating. Arterial signal and artery/vein contrast were higher with both bSSFP sampling schemes than with TOF. The kCE sequence allowed correct quantification of ten significant stenoses, and it facilitated the identification of an infrapetrous dysplasia, which was outside of the TOF imaging coverage. Non-ECG-gated bSSFP carotid imaging offers high-quality images and is a promising sequence for carotid disease diagnosis in a short acquisition time with high spatial resolution and a large field of view. • Non-ECG-gated unenhanced bSSFP MRA offers high-quality imaging of the carotid arteries. • Sequences using early acquisition of the k-space centre achieve higher image quality. • Non-ECG-gated unenhanced bSSFP MRA allows quantification of significant carotid stenosis. • Short MR acquisition times and ungated sequences are helpful in clinical practice. • High 3D spatial resolution and a large field of view improve diagnostic performance.

Respirators: Air Purifying, Self-Study, Course 40723

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

Chochoms, Michael

Respirators: Air Purifying Self-Study (COURSE 40723) is designed for Los Alamos National Laboratory (LANL) workers, support services subcontractors, and other LANL subcontractors who work under the LANL Respiratory Protection Program (RPP). This course also meets the air-purifying respirators (APRs) retraining requirement.

A study of respiration-correlated cone-beam CT scans to correct target positioning errors in radiotherapy of thoracic cancer

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

Santoro, J. P.; McNamara, J.; Yorke, E.

2012-10-15

Purpose: There is increasingly widespread usage of cone-beam CT (CBCT) for guiding radiation treatment in advanced-stage lung tumors, but difficulties associated with daily CBCT in conventionally fractionated treatments include imaging dose to the patient, increased workload and longer treatment times. Respiration-correlated cone-beam CT (RC-CBCT) can improve localization accuracy in mobile lung tumors, but further increases the time and workload for conventionally fractionated treatments. This study investigates whether RC-CBCT-guided correction of systematic tumor deviations in standard fractionated lung tumor radiation treatments is more effective than 2D image-based correction of skeletal deviations alone. A second study goal compares respiration-correlated vs respiration-averaged imagesmore » for determining tumor deviations. Methods: Eleven stage II-IV nonsmall cell lung cancer patients are enrolled in an IRB-approved prospective off-line protocol using RC-CBCT guidance to correct for systematic errors in GTV position. Patients receive a respiration-correlated planning CT (RCCT) at simulation, daily kilovoltage RC-CBCT scans during the first week of treatment and weekly scans thereafter. Four types of correction methods are compared: (1) systematic error in gross tumor volume (GTV) position, (2) systematic error in skeletal anatomy, (3) daily skeletal corrections, and (4) weekly skeletal corrections. The comparison is in terms of weighted average of the residual GTV deviations measured from the RC-CBCT scans and representing the estimated residual deviation over the treatment course. In the second study goal, GTV deviations computed from matching RCCT and RC-CBCT are compared to deviations computed from matching respiration-averaged images consisting of a CBCT reconstructed using all projections and an average-intensity-projection CT computed from the RCCT. Results: Of the eleven patients in the GTV-based systematic correction protocol, two required no

EPA Extends Comment Period for Draft Label Revisions on Respirators

EPA Pesticide Factsheets

Extending Comment Period for Draft Label Revisions on Respirators, Bring the respirator descriptions on pesticide labels into conformance with the current National Institute for Occupational Safety and Health (NIOSH) respirator language

Validation of the Spatial Accuracy of the ExacTracRTM Adaptive Gating System

NASA Astrophysics Data System (ADS)

Twork, Gregory

Stereotactic body radiation therapy (SBRT) is a method of treatment that is used in extracranial locations, including the abdominal and thoracic cavities, as well as spinal and paraspinal locations. At the McGill University Health Centre, liver SBRT treatments include gating, which places the treatment beam on a duty cycle controlled by tracking of fiducial markers moving with the patient's breathing cycle. Respiratory gated treatments aim to spare normal tissue, while delivering a dose properly to a moving target. The ExacTracRTM system (BrainLAB AG Germany) is an image-guided radiotherapy system consisting of a combination of infra-red (IR) cameras and dual kilovoltage (kV) X-ray tubes. The IR system is used to track patient positioning and respiratory motion, while the kV X-rays are used to determine a positional shift based on internal anatomy or fiducial markers. In order to validate the system's ability to treat under gating conditions, each step of the SBRT process was evaluated quantitatively. Initially the system was tested under ideal static conditions, followed by a study including gated parameters. The uncertainties of the isocenters, positioning algorithm, planning computed tomography (CT) and four dimensional CT (4DCT) scans, gating window size and tumor motion were evaluated for their contributions to the total uncertainty in treatment. The mechanical isocenter and 4DCT were found to be the largest sources of uncertainty. However, for tumors with large internal amplitudes (>2.25 cm) that are treated with large gating windows (>30%) the gating parameters can contribute more than 1.1 +/- 1.8 mm.

Down-regulation of respiration in pear fruit depends on temperature.

PubMed

Ho, Quang Tri; Hertog, Maarten L A T M; Verboven, Pieter; Ambaw, Alemayehu; Rogge, Seppe; Verlinden, Bert E; Nicolaï, Bart M

2018-04-09

The respiration rate of plant tissues decreases when the amount of available O2 is reduced. There is, however, a debate on whether the respiration rate is controlled either by diffusion limitation of oxygen or through regulatory processes at the level of the transcriptome. We used experimental and modelling approaches to demonstrate that both diffusion limitation and metabolic regulation affect the response of respiration of bulky plant organs such as fruit to reduced O2 levels in the surrounding atmosphere. Diffusion limitation greatly affects fruit respiration at high temperature, but at low temperature respiration is reduced through a regulatory process, presumably a response to a signal generated by a plant oxygen sensor. The response of respiration to O2 is time dependent and is highly sensitive, particularly at low O2 levels in the surrounding atmosphere. Down-regulation of the respiration at low temperatures may save internal O2 and relieve hypoxic conditions in the fruit.

Serial DNA relay in DNA logic gates by electrical fusion and mechanical splitting of droplets

PubMed Central

Kawano, Ryuji; Takinoue, Masahiro; Osaki, Toshihisa; Kamiya, Koki; Miki, Norihisa

2017-01-01

DNA logic circuits utilizing DNA hybridization and/or enzymatic reactions have drawn increasing attention for their potential applications in the diagnosis and treatment of cellular diseases. The compartmentalization of such a system into a microdroplet considerably helps to precisely regulate local interactions and reactions between molecules. In this study, we introduced a relay approach for enabling the transfer of DNA from one droplet to another to implement multi-step sequential logic operations. We proposed electrical fusion and mechanical splitting of droplets to facilitate the DNA flow at the inputs, logic operation, output, and serial connection between two logic gates. We developed Negative-OR operations integrated by a serial connection of the OR gate and NOT gate incorporated in a series of droplets. The four types of input defined by the presence/absence of DNA in the input droplet pair were correctly reflected in the readout at the Negative-OR gate. The proposed approach potentially allows for serial and parallel logic operations that could be used for complex diagnostic applications. PMID:28700641

Robust fluoroscopic respiratory gating for lung cancer radiotherapy without implanted fiducial markers

NASA Astrophysics Data System (ADS)

Cui, Ying; Dy, Jennifer G.; Sharp, Greg C.; Alexander, Brian; Jiang, Steve B.

2007-02-01

For gated lung cancer radiotherapy, it is difficult to generate accurate gating signals due to the large uncertainties when using external surrogates and the risk of pneumothorax when using implanted fiducial markers. We have previously investigated and demonstrated the feasibility of generating gating signals using the correlation scores between the reference template image and the fluoroscopic images acquired during the treatment. In this paper, we present an in-depth study, aiming at the improvement of robustness of the algorithm and its validation using multiple sets of patient data. Three different template generating and matching methods have been developed and evaluated: (1) single template method, (2) multiple template method, and (3) template clustering method. Using the fluoroscopic data acquired during patient setup before each fraction of treatment, reference templates are built that represent the tumour position and shape in the gating window, which is assumed to be at the end-of-exhale phase. For the single template method, all the setup images within the gating window are averaged to generate a composite template. For the multiple template method, each setup image in the gating window is considered as a reference template and used to generate an ensemble of correlation scores. All the scores are then combined to generate the gating signal. For the template clustering method, clustering (grouping of similar objects together) is performed to reduce the large number of reference templates into a few representative ones. Each of these methods has been evaluated against the reference gating signal as manually determined by a radiation oncologist. Five patient datasets were used for evaluation. In each case, gated treatments were simulated at both 35% and 50% duty cycles. False positive, negative and total error rates were computed. Experiments show that the single template method is sensitive to noise; the multiple template and clustering methods are more

20 CFR 410.462 - Presumption relating to respirable disease.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Presumption relating to respirable disease... Pneumoconiosis § 410.462 Presumption relating to respirable disease. (a) Even though the existence of... was employed for 10 years or more in the Nation's coal mines and died from a respirable disease, it...

20 CFR 410.462 - Presumption relating to respirable disease.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Presumption relating to respirable disease... Pneumoconiosis § 410.462 Presumption relating to respirable disease. (a) Even though the existence of... was employed for 10 years or more in the Nation's coal mines and died from a respirable disease, it...

Markerless gating for lung cancer radiotherapy based on machine learning techniques

NASA Astrophysics Data System (ADS)

Lin, Tong; Li, Ruijiang; Tang, Xiaoli; Dy, Jennifer G.; Jiang, Steve B.

2009-03-01

In lung cancer radiotherapy, radiation to a mobile target can be delivered by respiratory gating, for which we need to know whether the target is inside or outside a predefined gating window at any time point during the treatment. This can be achieved by tracking one or more fiducial markers implanted inside or near the target, either fluoroscopically or electromagnetically. However, the clinical implementation of marker tracking is limited for lung cancer radiotherapy mainly due to the risk of pneumothorax. Therefore, gating without implanted fiducial markers is a promising clinical direction. We have developed several template-matching methods for fluoroscopic marker-less gating. Recently, we have modeled the gating problem as a binary pattern classification problem, in which principal component analysis (PCA) and support vector machine (SVM) are combined to perform the classification task. Following the same framework, we investigated different combinations of dimensionality reduction techniques (PCA and four nonlinear manifold learning methods) and two machine learning classification methods (artificial neural networks—ANN and SVM). Performance was evaluated on ten fluoroscopic image sequences of nine lung cancer patients. We found that among all combinations of dimensionality reduction techniques and classification methods, PCA combined with either ANN or SVM achieved a better performance than the other nonlinear manifold learning methods. ANN when combined with PCA achieves a better performance than SVM in terms of classification accuracy and recall rate, although the target coverage is similar for the two classification methods. Furthermore, the running time for both ANN and SVM with PCA is within tolerance for real-time applications. Overall, ANN combined with PCA is a better candidate than other combinations we investigated in this work for real-time gated radiotherapy.

Deletion of cytosolic gating ring decreases gate and voltage sensor coupling in BK channels.

PubMed

Zhang, Guohui; Geng, Yanyan; Jin, Yakang; Shi, Jingyi; McFarland, Kelli; Magleby, Karl L; Salkoff, Lawrence; Cui, Jianmin

2017-03-06

Large conductance Ca 2+ -activated K + channels (BK channels) gate open in response to both membrane voltage and intracellular Ca 2+ The channel is formed by a central pore-gate domain (PGD), which spans the membrane, plus transmembrane voltage sensors and a cytoplasmic gating ring that acts as a Ca 2+ sensor. How these voltage and Ca 2+ sensors influence the common activation gate, and interact with each other, is unclear. A previous study showed that a BK channel core lacking the entire cytoplasmic gating ring (Core-MT) was devoid of Ca 2+ activation but retained voltage sensitivity (Budelli et al. 2013. Proc. Natl. Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1313433110). In this study, we measure voltage sensor activation and pore opening in this Core-MT channel over a wide range of voltages. We record gating currents and find that voltage sensor activation in this truncated channel is similar to WT but that the coupling between voltage sensor activation and gating of the pore is reduced. These results suggest that the gating ring, in addition to being the Ca 2+ sensor, enhances the effective coupling between voltage sensors and the PGD. We also find that removal of the gating ring alters modulation of the channels by the BK channel's β1 and β2 subunits. © 2017 Zhang et al.

Deletion of cytosolic gating ring decreases gate and voltage sensor coupling in BK channels

PubMed Central

Zhang, Guohui; Shi, Jingyi; McFarland, Kelli; Magleby, Karl L.; Salkoff, Lawrence

2017-01-01

Large conductance Ca2+-activated K+ channels (BK channels) gate open in response to both membrane voltage and intracellular Ca2+. The channel is formed by a central pore-gate domain (PGD), which spans the membrane, plus transmembrane voltage sensors and a cytoplasmic gating ring that acts as a Ca2+ sensor. How these voltage and Ca2+ sensors influence the common activation gate, and interact with each other, is unclear. A previous study showed that a BK channel core lacking the entire cytoplasmic gating ring (Core-MT) was devoid of Ca2+ activation but retained voltage sensitivity (Budelli et al. 2013. Proc. Natl. Acad. Sci. USA. http://dx.doi.org/10.1073/pnas.1313433110). In this study, we measure voltage sensor activation and pore opening in this Core-MT channel over a wide range of voltages. We record gating currents and find that voltage sensor activation in this truncated channel is similar to WT but that the coupling between voltage sensor activation and gating of the pore is reduced. These results suggest that the gating ring, in addition to being the Ca2+ sensor, enhances the effective coupling between voltage sensors and the PGD. We also find that removal of the gating ring alters modulation of the channels by the BK channel’s β1 and β2 subunits. PMID:28196879

Watershed-Scale Heterogeneity of the Biophysical Controls on Soil Respiration

NASA Astrophysics Data System (ADS)

Riveros, D. A.; Pacific, V. J.; McGlynn, B. L.; Welsch, D. L.; Epstein, H. E.; Muth, D. J.; Marshall, L.; Wraith, J.

2006-12-01

Large gaps exist in our understanding of the variability of soil respiration response to changing hydrologic conditions across spatial and temporal scales. Determining the linkages between the hydrologic cycle and the biophysical controls of soil respiration from the local point, to the plot, to the watershed scale is critical to understanding the dynamics of net ecosystem CO2 exchange (NEE). To study the biophysical controls of soil respiration, we measured soil CO2 concentration, soil CO2 flux, dissolved CO2 in stream water, soil moisture, soil temperature, groundwater dynamics, and precipitation at 20-minute intervals throughout the growing season at 4 sites and at weekly intervals at 62 sites covering the range of topographic position, slope, aspect, land cover, and upslope accumulated area conditions in a 555-ha subalpine watershed in central Montana. Our goal was to quantify watershed-scale heterogeneity in soil CO2 concentrations and surface efflux and gain understanding of the biophysical controls on soil respiration. We seek to improve our ability to evaluate and predict soil respiration responses to a dynamic hydrologic cycle across multiple temporal and spatial scales. We found that time lags between biophysical controls and soil respiration can occur from hourly to daily scales. The sensitivity of soil respiration to changes in environmental conditions is controlled by the antecedent soil moisture and by topographic position. At the watershed scale, significant differences in soil respiration exist between upland (dry) and lowland (wet) sites. However, differences in the magnitude and timing of soil respiration also exist within upland settings due to heterogeneity in soil temperature, soil moisture, and soil organic matter. Finally, we used a process-based model to simulate respiration at different times of the year across spatial locations. Our simulations highlight the importance of autotrophic and heterotrophic respiration (production) over

Quantifying the influence of respiration and cardiac pulsations on cerebrospinal fluid dynamics using real-time phase-contrast MRI.

PubMed

Yildiz, Selda; Thyagaraj, Suraj; Jin, Ning; Zhong, Xiaodong; Heidari Pahlavian, Soroush; Martin, Bryn A; Loth, Francis; Oshinski, John; Sabra, Karim G

2017-08-01

To validate a real-time phase contrast magnetic resonance imaging (RT-PCMRI) sequence in a controlled phantom model, and to quantify the relative contributions of respiration and cardiac pulsations on cerebrospinal fluid (CSF) velocity at the level of the foramen magnum (FM). To validate the 3T MRI techniques, in vitro studies used a realistic model of the spinal subarachnoid space driven by pulsatile flow waveforms mimicking the respiratory and cardiac components of CSF flow. Subsequently, CSF flow was measured continuously during 1-minute RT-PCMRI acquisitions at the FM while healthy subjects (N = 20) performed natural breathing, deep breathing, breath-holding, and coughing. Conventional cardiac-gated PCMRI was obtained for comparison. A frequency domain power ratio analysis determined the relative contribution of respiration versus cardiac ([r/c]) components of CSF velocity. In vitro studies demonstrating the accuracy of RT-PCMRI within 5% of input values showed that conventional PCMRI measures only the cardiac component of CSF velocity (0.42 ± 0.02 cm/s), averages out respiratory effects, and underestimates the magnitude of CSF velocity (0.96 ± 0.07 cm/s). In vivo RT-PCMRI measurements indicated the ratio of respiratory to cardiac velocity pulsations averaged over all subjects as [r/c = 0.14 ± 0.27] and [r/c = 0.40 ± 0.47] for natural and deep breathing, respectively. During coughing, the peak CSF velocity increased by a factor of 2.27 ± 1.40. RT-PCMRI can noninvasively measure instantaneous CSF velocity driven by cardiac pulsations, respiration, and coughing in real time. A comparable contribution of respiration and cardiac pulsations on CSF velocity was found during deep breathing but not during natural breathing. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:431-439. © 2017 International Society for Magnetic Resonance in Medicine.

Implementing conventional logic unconventionally: photochromic molecular populations as registers and logic gates.

PubMed

Chaplin, J C; Russell, N A; Krasnogor, N

2012-07-01

In this paper we detail experimental methods to implement registers, logic gates and logic circuits using populations of photochromic molecules exposed to sequences of light pulses. Photochromic molecules are molecules with two or more stable states that can be switched reversibly between states by illuminating with appropriate wavelengths of radiation. Registers are implemented by using the concentration of molecules in each state in a given sample to represent an integer value. The register's value can then be read using the intensity of a fluorescence signal from the sample. Logic gates have been implemented using a register with inputs in the form of light pulses to implement 1-input/1-output and 2-input/1-output logic gates. A proof of concept logic circuit is also demonstrated; coupled with the software workflow describe the transition from a circuit design to the corresponding sequence of light pulses. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Advanced insulated gate bipolar transistor gate drive

DOEpatents

Short, James Evans [Monongahela, PA; West, Shawn Michael [West Mifflin, PA; Fabean, Robert J [Donora, PA

2009-08-04

A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

Improved scatterer property estimates from ultrasound backscatter for small gate lengths using a gate-edge correction factor

NASA Astrophysics Data System (ADS)

Oelze, Michael L.; O'Brien, William D.

2004-11-01

Backscattered rf signals used to construct conventional ultrasound B-mode images contain frequency-dependent information that can be examined through the backscattered power spectrum. The backscattered power spectrum is found by taking the magnitude squared of the Fourier transform of a gated time segment corresponding to a region in the scattering volume. When a time segment is gated, the edges of the gated regions change the frequency content of the backscattered power spectrum due to truncating of the waveform. Tapered windows, like the Hanning window, and longer gate lengths reduce the relative contribution of the gate-edge effects. A new gate-edge correction factor was developed that partially accounted for the edge effects. The gate-edge correction factor gave more accurate estimates of scatterer properties at small gate lengths compared to conventional windowing functions. The gate-edge correction factor gave estimates of scatterer properties within 5% of actual values at very small gate lengths (less than 5 spatial pulse lengths) in both simulations and from measurements on glass-bead phantoms. While the gate-edge correction factor gave higher accuracy of estimates at smaller gate lengths, the precision of estimates was not improved at small gate lengths over conventional windowing functions. .

Respiration of the external mycelium in the arbuscular mycorrhizal symbiosis shows strong dependence on recent photosynthates and acclimation to temperature.

PubMed

Heinemeyer, A; Ineson, P; Ostle, N; Fitter, A H

2006-01-01

* Although arbuscular mycorrhizal (AM) fungi are a major pathway in the global carbon cycle, their basic biology and, in particular, their respiratory response to temperature remain obscure. * A pulse label of the stable isotope (13)C was applied to Plantago lanceolata, either uninoculated or inoculated with the AM fungus Glomus mosseae. The extra-radical mycelium (ERM) of the fungus was allowed to grow into a separate hyphal compartment excluding roots. We determined the carbon costs of the ERM and tested for a direct temperature effect on its respiration by measuring total carbon and the (13)C:(12)C ratio of respired CO(2). With a second pulse we tested for acclimation of ERM respiration after 2 wk of soil warming. * Root colonization remained unchanged between the two pulses but warming the hyphal compartment increased ERM length. delta(13)C signals peaked within the first 10 h and were higher in mycorrhizal treatments. The concentration of CO(2) in the gas samples fluctuated diurnally and was highest in the mycorrhizal treatments but was unaffected by temperature. Heating increased ERM respiration only after the first pulse and reduced specific ERM respiration rates after the second pulse; however, both pulses strongly depended on radiation flux. * The results indicate a fast ERM acclimation to temperature, and that light is the key factor controlling carbon allocation to the fungus.

Recent Radiation Test Results for Trench Power MOSFETs

NASA Technical Reports Server (NTRS)

Lauenstein, Jean-Marie; Casey, Megan C.; Wilcox, Edward P.; Phan, Anthony M.; Kim, Hak S.; Topper, Alyson D.; Ladbury, Raymond L.; Label, Kenneth A.

2017-01-01

Single-event effect (SEE) radiation test results are presented for various trench-gate power MOSFETs. The heavy-ion response of the first (and only) radiation-hardened trench-gate power MOSFET is evaluated: the manufacturer SEE response curve is verified and importantly, no localized dosing effects are measured, distinguishing it from other, non-hardened trench-gate power MOSFETs. Evaluations are made of n-type commercial and both n- and p-type automotive grade trench-gate device using ions comparable to of those on the low linear energy transfer (LET) side of the iron knee of the galactic cosmic ray spectrum, to explore suitability of these parts for missions with higher risk tolerance and shorter duration, such as CubeSats. Part-to-part variability of SEE threshold suggests testing with larger sample sizes and applying more aggressive derating to avoid on-orbit failures. The n-type devices yielded expected localized dosing effects including when irradiated in an unbiased (0-V) configuration, adding to the challenge of inserting these parts into space flight missions.

Effects of simulated warming on soil respiration to XiaoPo lake

NASA Astrophysics Data System (ADS)

Zhao, Shuangkai; Chen, Kelong; Wu, Chengyong; Mao, Yahui

2018-02-01

The main flux of carbon cycling in terrestrial and atmospheric ecosystems is soil respiration, and soil respiration is one of the main ways of soil carbon output. This is of great significance to explore the dynamic changes of soil respiration rate and its effect on temperature rise, and the correlation between environmental factors and soil respiration. In this study, we used the open soil carbon flux measurement system (LI-8100, LI-COR, NE) in the experimental area of the XiaoPo Lake wetland in the Qinghai Lake Basin, and the Kobresia (Rs) were measured, and the soil respiration was simulated by simulated temperature (OTC) and natural state. The results showed that the temperature of 5 cm soil was 1.37 °C higher than that of the control during the experiment, and the effect of warming was obvious. The respiration rate of soil under warming and natural conditions showed obvious diurnal variation and monthly variation. The effect of warming on soil respiration rate was promoted and the effect of precipitation on soil respiration rate was inhibited. Further studies have shown that the relationship between soil respiration and 5 cm soil temperature under the control and warming treatments can be described by the exponential equation, and the correlation analysis between the two plots shows a very significant exponential relationship (p < 0.001). The warming treatment not only increased the Q10 value of soil respiration rate, but also increased the sensitivity of soil respiration rate. The relationship between soil respiration and soil moisture can be explained by the quadratic linear equation (p < 0.05). It can be concluded that under the condition of sufficient rainfall, the soil temperature is the main influencing factor of soil respiration in this region.

How much work is expended for respiration?

PubMed

Johnson, A T

1993-01-01

The rate of work expended to move air in the respiratory system has been determined for five different airflow waveshapes, a non-linear respiratory model and five exercise levels. As expected, the rectangular waveshape was the most efficient. Model conditions were then changed one a time: (i) starting lung volume was allowed to vary, (ii) exhalation flow limitation was added, (iii) respiration was considered to be a metabolic burden determining part of the ventilation requirement and (iv) a respirator mask was added. Although there is no direct work advantage to varying initial lung volume, such volume changes appear to be dictated by the asymmetry of lung recoil pressure about the lung relaxation volume; allowing the work of respiration to become a metabolic burden clearly shows why respiratory waveforms change from rest to exercise; and, adding a respirator imposes a severe respiratory burden on the wearer engaging in moderate, heavy and very heavy exercise.

Do Tree Stems Recapture Respired CO2?

NASA Astrophysics Data System (ADS)

Hilman, B.; Angert, A.

2016-12-01

Tree stem respiration is an important, yet not well understood, component of the terrestrial carbon cycle. Predicting how trees as whole organisms respond to changes in climate and atmospheric CO2 requires understanding of the variability in the fraction of assimilated carbon allocated to respiration, versus the allocation to growth, damage repair, and to rhizosphere symbionts. Here we used the ratio of CO2 efflux/O2 influx (Apparent Respiratory Quotient, ARQ) to study stem respiration. The ARQ in trees stems is predicted to be 1.0, as a result of carbohydrates metabolism. Lower than 1.0 ARQ values may indicate a local assimilation of respired CO2, or dissolution and transport of CO2 in the xylem stream. We measured stems ARQ in 16 tree species at tropical, Mediterranean and temperate ecosystems using stem chambers and in-vitro incubations. The CO2 and O2 were measured by a system we developed, which is based on an IRGA and a Fuel-cell O2 analyzer (Hilman and Angert 2016). We found typical values of ARQ in the range of 0.4-0.8. Since incubations of detach stem tissues yielded similar ARQ values, and since the influence of natural variations in the transpiration stream on ARQ was found to be small, we conclude that the removal of the respired CO2 is not via dissolution in the xylem stream. Using 13C labeling, dark fixation of stem tissues was detected, which is most probably phosphoenolpyruvate carboxylase (PEPC) mediated. Hence, we suggest that in-stem dark fixation of respired CO2 to organic acids (e.g. malate) affects the outgoing efflux. Further research should determine if these organic acids are transported to the canopy, stored in the stem, or transported to the roots to serve as exudates. Hilman B, Angert A (2016) Measuring the ratio of CO2 efflux to O2 influx in tree stem respiration. Tree Physiol 2016, doi: 10.1093/treephys/tpw057

DIFMOS - A floating-gate electrically erasable nonvolatile semiconductor memory technology. [Dual Injector Floating-gate MOS

NASA Technical Reports Server (NTRS)

Gosney, W. M.

1977-01-01

Electrically alterable read-only memories (EAROM's) or reprogrammable read-only memories (RPROM's) can be fabricated using a single-level metal-gate p-channel MOS technology with all conventional processing steps. Given the acronym DIFMOS for dual-injector floating-gate MOS, this technology utilizes the floating-gate technique for nonvolatile storage of data. Avalanche injection of hot electrons through gate oxide from a special injector diode in each bit is used to charge the floating gates. A second injector structure included in each bit permits discharge of the floating gate by avalanche injection of holes through gate oxide. The overall design of the DIFMOS bit is dictated by the physical considerations required for each of the avalanche injector types. The end result is a circuit technology which can provide fully decoded bit-erasable EAROM-type circuits using conventional manufacturing techniques.

20 CFR 718.303 - Death from a respirable disease.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Death from a respirable disease. 718.303... Death from a respirable disease. (a)(1) If a deceased miner was employed for ten or more years in one or more coal mines and died from a respirable disease, there shall be a rebuttable presumption that his or...

30 CFR 70.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

30 CFR 70.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

30 CFR 70.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

30 CFR 70.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

Breathing simulator of workers for respirator performance test

PubMed Central

YUASA, Hisashi; KUMITA, Mikio; HONDA, Takeshi; KIMURA, Kazushi; NOZAKI, Kosuke; EMI, Hitoshi; OTANI, Yoshio

2014-01-01

Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker’s respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns. PMID:25382381

Breathing simulator of workers for respirator performance test.

PubMed

Yuasa, Hisashi; Kumita, Mikio; Honda, Takeshi; Kimura, Kazushi; Nozaki, Kosuke; Emi, Hitoshi; Otani, Yoshio

2015-01-01

Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker's respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns.

Energetics of Respiration and Oxidative Phosphorylation in Mycobacteria.

PubMed

Cook, Gregory M; Hards, Kiel; Vilchèze, Catherine; Hartman, Travis; Berney, Michael

2014-06-01

Mycobacteria inhabit a wide range of intracellular and extracellular environments. Many of these environments are highly dynamic and therefore mycobacteria are faced with the constant challenge of redirecting their metabolic activity to be commensurate with either replicative growth or a non-replicative quiescence. A fundamental feature in this adaptation is the ability of mycobacteria to respire, regenerate reducing equivalents and generate ATP via oxidative phosphorylation. Mycobacteria harbor multiple primary dehydrogenases to fuel the electron transport chain and two terminal respiratory oxidases, an aa3 -type cytochrome c oxidase and cytochrome bd-type menaquinol oxidase, are present for dioxygen reduction coupled to the generation of a protonmotive force. Hypoxia leads to the downregulation of key respiratory complexes, but the molecular mechanisms regulating this expression are unknown. Despite being obligate aerobes, mycobacteria have the ability to metabolize in the absence of oxygen and a number of reductases are present to facilitate the turnover of reducing equivalents under these conditions (e.g. nitrate reductase, succinate dehydrogenase/fumarate reductase). Hydrogenases and ferredoxins are also present in the genomes of mycobacteria suggesting the ability of these bacteria to adapt to an anaerobic-type of metabolism in the absence of oxygen. ATP synthesis by the membrane-bound F1FO-ATP synthase is essential for growing and non-growing mycobacteria and the enzyme is able to function over a wide range of protonmotive force values (aerobic to hypoxic). The discovery of lead compounds that target respiration and oxidative phosphorylation in Mycobacterium tuberculosis highlights the importance of this area for the generation of new front line drugs to combat tuberculosis.

Impact of gate geometry on ionic liquid gated ionotronic systems

DOE PAGES

Wong, Anthony T.; Noh, Joo Hyon; Pudasaini, Pushpa Raj; ...

2017-01-23

Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard “side gate” 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. Finally, these findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

Historical climate controls soil respiration responses to current soil moisture.

PubMed

Hawkes, Christine V; Waring, Bonnie G; Rocca, Jennifer D; Kivlin, Stephanie N

2017-06-13

Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40-70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil moisture, which remain unresolved in ecosystem models. A common assumption of large-scale models is that soil microorganisms respond to moisture in the same way, regardless of location or climate. Here, we show that soil respiration is constrained by historical climate. We find that historical rainfall controls both the moisture dependence and sensitivity of respiration. Moisture sensitivity, defined as the slope of respiration vs. moisture, increased fourfold across a 480-mm rainfall gradient, resulting in twofold greater carbon loss on average in historically wetter soils compared with historically drier soils. The respiration-moisture relationship was resistant to environmental change in field common gardens and field rainfall manipulations, supporting a persistent effect of historical climate on microbial respiration. Based on these results, predicting future carbon cycling with climate change will require an understanding of the spatial variation and temporal lags in microbial responses created by historical rainfall.

Resazurin as a Proxy for Estimating Stream Respiration

NASA Astrophysics Data System (ADS)

Gonzalez Pinzon, R. A.; Haggerty, R.; Argerich, A.; Briggs, M.; Lautz, L. K.; Lemke, D.; Hare, D. K.

2010-12-01

Hydrologic retention in stream ecosystems favors the reactions of solutes and nutrients in metabolically active transient storage (MATS) zones. These zones are hot spots where metabolic activity is expected to contribute significantly to ecosystem respiration. We compare the results of a series of coinjections of resazurin (Raz) as a redox sensitive tracer, and NaCl as a conservative tracer to investigate the function of MATS zones. Raz is a dye that undergoes an irreversible reduction to resorufin (Rru) when exposed to aerobic respiration. To characterize the transformation of Raz we measured the BTC of the tracers at the boundary conditions, and during plateau concentrations we sampled the longitudinal profile of surface water. We also used the two-station diel technique to quantify gross primary production (GPP) and community respiration (CR) within the reaches. Injections have been performed in streams with different morphology, streambed composition, and riparian vegetation in Oregon-USA (WS 1 and WS 3 in the HJ Andrews Forest LTER, and Drift Creek), Spain (Riera de Santa Fe del Montseny, Catalonia) and Wyoming-USA (Cherry Creek). The results support the idea that under different ranges of community respiration, the transformation of Raz to Rru is a proxy for quantifying MATS, characterizing spatial heterogeneity in respiration rates, and ultimately, could be used to estimate ecosystem respiration in environments where direct measurement is challenging.

Effects of respirators under heat/work conditions

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

James, R.; Dukes-Dobos, F.; Smith, R.

Physiological responses and perceived strain of five unacclimatized male subjects were studied. The subjects were exposed to heat during an exercise task and were evaluated while wearing half and full facepiece, cartridge-type, air-purifying respirators, and without a respirator. The exercise consisted of walking on a treadmill for a period of 1 hour in a controlled environmental chamber at each of two different energy expenditure levels (200 and 400 kcal/hr)(approx. = 58 and 116 Watts) and two different heat exposures (air temperatures of 25/sup 0/C and 43.3./sup 0/C). The results indicated that wearing a full facepiece respirator imposed significant physiological strainmore » added to that caused by the heat and workloads used in the study. Five of the six physiological measures show this increased physiological strain: (1) heart rate; (2) minute ventilation; (3) oxygen consumption; (4) energy expenditure; and (5) oral temperature. There was no detectable effect on sweat rate. Although subjective ratings indicated more discomfort with increasing physiological strain, the observed correlations between such measures were low (T/sub b/ < .60). The net consequence of the significant effects indicates that workers' tolerance to moderate or high levels of work under hot conditions while wearing a respirator is reduced. The reduction is more pronounced when wearing a full mask than when wearing a half mask. Changes in respirator design which minimize respiratory dead space are suggested to alleviate this problem. Otherwise, prevention of excessive physiological strain from respirator use when working at moderate or higher levels at hot job sites could necessitate more rest breaks or limiting work time under such conditions.« less

Abnormal mitochondrial respiration in failed human myocardium.

PubMed

Sharov, V G; Todor, A V; Silverman, N; Goldstein, S; Sabbah, H N

2000-12-01

Chronic heart failure (HF) is associated with morphologic abnormalities of cardiac mitochondria including hyperplasia, reduced organelle size and compromised structural integrity. In this study, we examined whether functional abnormalities of mitochondrial respiration are also present in myocardium of patients with advanced HF. Mitochondrial respiration was examined using a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles obtained from myocardium of failed explanted human hearts due to ischemic (ICM, n=9) or idiopathic dilated (IDC, n=9) cardiomyopathy. Myocardial specimens from five normal donor hearts served as controls (CON). Basal respiratory rate, respiratory rate after addition of the substrates glutamate and malate (V(SUB)), state 3 respiration (after addition of ADP, V(ADP)) and respiration after the addition of atractyloside (V(AT)) were measured in scar-free muscle bundles obtained from the subendocardial (ENDO) and subepicardial (EPI) thirds of the left ventricular (LV) free wall, interventricular septum and right ventricular (RV) free wall. There were no differences in basal and substrate-supported respiration between CON and HF regardless of etiology. V(ADP)was significantly depressed both in ICM and IDC compared to CON in all the regions studied. The respiratory control ratio, V(ADP)/V(AT), was also significantly decreased in HF compared to CON. In both ICM and IDC, V(ADP)was significantly lower in ENDO compared to EPI. The results indicate that mitochondrial respiration is abnormal in the failing human heart. The findings support the concept of low myocardial energy production in HF via oxidative phosphorylation, an abnormality with a potentially impact on global cardiac performance. Copyright 2000 Academic Press.

Recommended test methods and pass/fail criteria for a respirator fit capability test of half-mask air-purifying respirators

PubMed Central

Zhuang, Ziqing; Bergman, Michael; Lei, Zhipeng; Niezgoda, George; Shaffer, Ronald

2017-01-01

This study assessed key test parameters and pass/fail criteria options for developing a respirator fit capability (RFC) test for half-mask air-purifying particulate respirators. Using a 25-subject test panel, benchmark RFC data were collected for 101 National Institute for Occupational Safety and Health-certified respirator models. These models were further grouped into 61 one-, two-, or three-size families. Fit testing was done using a PortaCount® Plus with N95-Companion accessory and an Occupational Safety and Health Administration-accepted quantitative fit test protocol. Three repeated tests (donnings) per subject/respirator model combination were performed. The panel passing rate (PPR) (number or percentage of the 25-subject panel achieving acceptable fit) was determined for each model using five different alternative criteria for determining acceptable fit. When the 101 models are evaluated individually (i.e., not grouped by families), the percentages of models capable of fitting >75% (19/25 subjects) of the panel were 29% and 32% for subjects achieving a fit factor ≥100 for at least one of the first two donnings and at least one of three donnings, respectively. When the models are evaluated grouped into families and using >75% of panel subjects achieving a fit factor ≥100 for at least one of two donnings as the PPR pass/fail criterion, 48% of all models can pass. When >50% (13/25 subjects) of panel subjects was the PPR criterion, the percentage of passing models increased to 70%. Testing respirators grouped into families and evaluating the first two donnings for each of two respirator sizes provided the best balance between meeting end user expectations and creating a performance bar for manufacturers. Specifying the test criterion for a subject obtaining acceptable fit as achieving a fit factor ≥100 on at least one out of the two donnings is reasonable because a majority of existing respirator families can achieve an PPR of >50% using this criterion

Recommended test methods and pass/fail criteria for a respirator fit capability test of half-mask air-purifying respirators.

PubMed

Zhuang, Ziqing; Bergman, Michael; Lei, Zhipeng; Niezgoda, George; Shaffer, Ronald

2017-06-01

This study assessed key test parameters and pass/fail criteria options for developing a respirator fit capability (RFC) test for half-mask air-purifying particulate respirators. Using a 25-subject test panel, benchmark RFC data were collected for 101 National Institute for Occupational Safety and Health-certified respirator models. These models were further grouped into 61 one-, two-, or three-size families. Fit testing was done using a PortaCount® Plus with N95-Companion accessory and an Occupational Safety and Health Administration-accepted quantitative fit test protocol. Three repeated tests (donnings) per subject/respirator model combination were performed. The panel passing rate (PPR) (number or percentage of the 25-subject panel achieving acceptable fit) was determined for each model using five different alternative criteria for determining acceptable fit. When the 101 models are evaluated individually (i.e., not grouped by families), the percentages of models capable of fitting >75% (19/25 subjects) of the panel were 29% and 32% for subjects achieving a fit factor ≥100 for at least one of the first two donnings and at least one of three donnings, respectively. When the models are evaluated grouped into families and using >75% of panel subjects achieving a fit factor ≥100 for at least one of two donnings as the PPR pass/fail criterion, 48% of all models can pass. When >50% (13/25 subjects) of panel subjects was the PPR criterion, the percentage of passing models increased to 70%. Testing respirators grouped into families and evaluating the first two donnings for each of two respirator sizes provided the best balance between meeting end user expectations and creating a performance bar for manufacturers. Specifying the test criterion for a subject obtaining acceptable fit as achieving a fit factor ≥100 on at least one out of the two donnings is reasonable because a majority of existing respirator families can achieve an PPR of >50% using this criterion

Enhancing the carbon capture capacities of a rigid ultra-microporous MOF through gate-opening at low CO2 pressures assisted by swiveling oxalate pillars.

PubMed

Banerjee, Aparna; Nandi, Shyamapada; Nasa, Parveen; Vaidhyanathan, Ramanathan

2016-01-31

Porosity enhancement assisted by an unusual gate opening has been realized in an exceptionally rigid ultra-microporous framework. The gate-opening has been attributed to the presence of symmetrically positioned Zn-O bonds of the Zn-oxalate units that facilitate subtle swiveling motion resulting in a drastic improvement (42%) in the CO2 capacity without compromising the CO2/N2 selectivity.

Seasonality of temperate forest photosynthesis and daytime respiration.

PubMed

Wehr, R; Munger, J W; McManus, J B; Nelson, D D; Zahniser, M S; Davidson, E A; Wofsy, S C; Saleska, S R

2016-06-30

Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment. The consequent view of temperate deciduous forests (an important CO2 sink) is that, first, ecosystem respiration is greater during the day than at night; and second, ecosystem photosynthetic light-use efficiency peaks after leaf expansion in spring and then declines, presumably because of leaf ageing or water stress. This view has underlain the development of terrestrial biosphere models used in climate prediction and of remote sensing indices of global biosphere productivity. Here, we use new isotopic instrumentation to determine ecosystem photosynthesis and daytime respiration in a temperate deciduous forest over a three-year period. We find that ecosystem respiration is lower during the day than at night-the first robust evidence of the inhibition of leaf respiration by light at the ecosystem scale. Because they do not capture this effect, standard approaches overestimate ecosystem photosynthesis and daytime respiration in the first half of the growing season at our site, and inaccurately portray ecosystem photosynthetic light-use efficiency. These findings revise our understanding of forest-atmosphere carbon exchange, and provide a basis for investigating how leaf-level physiological dynamics manifest at the canopy scale in other ecosystems.

The four-gate transistor

NASA Technical Reports Server (NTRS)

Mojarradi, M. M.; Cristoveanu, S.; Allibert, F.; France, G.; Blalock, B.; Durfrene, B.

2002-01-01

The four-gate transistor or G4-FET combines MOSFET and JFET principles in a single SOI device. Experimental results reveal that each gate can modulate the drain current. Numerical simulations are presented to clarify the mechanisms of operation. The new device shows enhanced functionality, due to the combinatorial action of the four gates, and opens rather revolutionary applications.

Root Zone Respiration on Hydroponically Grown Wheat Plant Systems

NASA Technical Reports Server (NTRS)

Soler-Crespo, R. A.; Monje, O. A.

2010-01-01

Root respiration is a biological phenomenon that controls plant growth and physiological development during a plant's lifespan. This process is dependent on the availability of oxygen in the system where the plant is located. In hydroponic systems, where plants are submerged in a solution containing vital nutrients but no type of soil, the availability of oxygen arises from the dissolved oxygen concentration in the solution. This oxygen concentration is dependent on the , gas-liquid interface formed on the upper surface of the liquid, as given by Henry's Law, depending on pressure and temperature conditions. Respiration rates of the plants rise as biomass and root zone increase with age. The respiration rate of Apogee wheat plants (Triticum aestivum) was measured as a function of light intensity (catalytic for photosynthesis) and CO2 concentration to determine their effect on respiration rates. To determine their effects on respiration rate and plant growth microbial communities were introduced into the system, by Innoculum. Surfactants were introduced, simulating gray-water usage in space, as another factor to determine their effect on chemical oxygen demand of microbials and on respiration rates of the plants. It is expected to see small effects from changes in CO2 concentration or light levels, and to see root respiration decrease in an exponential manner with plant age and microbial activity.

Direct reading of electrocardiograms and respiration rates

NASA Technical Reports Server (NTRS)

Wise, J. P.

1969-01-01

Technique for reading heart and respiration rates is more accurate and direct than the previous method. Index of a plastic calibrated card is aligned with a point on the electrocardiogram. Complexes are counted as indicated on the card and heart or respiration rate is read directly from the appropriate scale.

Active Site Gate Dynamics Modulate the Catalytic Activity of the Ubiquitination Enzyme E2-25K.

PubMed

Rout, Manoj K; Lee, Brian L; Lin, Aiyang; Xiao, Wei; Spyracopoulos, Leo

2018-05-03

The ubiquitin proteasome system (UPS) signals for degradation of proteins through attachment of K48-linked polyubiquitin chains, or alterations in protein-protein recognition through attachment of K63-linked chains. Target proteins are ubiquitinated in three sequential chemical steps by a three-component enzyme system. Ubiquitination, or E2 enzymes, catalyze the central step by facilitating reaction of a target protein lysine with the C-terminus of Ub that is attached to the active site cysteine of the E2 through a thioester bond. E2 reactivity is modulated by dynamics of an active site gate, whose central residue packs against the active site cysteine in a closed conformation. Interestingly, for the E2 Ubc13, which specifically catalyzes K63-linked ubiquitination, the central gate residue adopts an open conformation. We set out to determine if active site gate dynamics play a role in catalysis for E2-25K, which adopts the canonical, closed gate conformation, and which selectively synthesizes K48-linked ubiquitin chains. Gate dynamics were characterized using mutagenesis of key residues, combined with enzyme kinetics measurements, and main chain NMR relaxation. The experimental data were interpreted with all atom MD simulations. The data indicate that active site gate opening and closing rates for E2-25K are precisely balanced.

Thinning but not understory removal increased heterotrophic respiration and total soil respiration in Pinus massoniana stands.

PubMed

Lei, Lei; Xiao, Wenfa; Zeng, Lixiong; Zhu, Jianhua; Huang, Zhilin; Cheng, Ruimei; Gao, Shangkun; Li, Mai-He

2018-04-15

Quantifying soil respiration (R s ) and its components [autotrophic respiration (R a ) and heterotrophic respiration (R h )] in relation to forest management is vital to accurately evaluate forest carbon balance. Thus, R s , R a , and R h were continuously monitored from November 2013 to November 2016 in Pinus massoniana forests subjected to four different management practices in China. We hypothesized that understory removal and thinning decrease R a and R h and thus R s , and these decreases will change with time following UR and thinning. Mean values of R s , R a , and R h in light thinned plots (LT=15% of tree basal area thinned) and heavily thinned plots (HT=70% of tree basal area thinned) were significantly higher than in control (CK) and understory removal plots (UR). The annual R h /R s ratio ranged from 58% to 70% across all treatments, and this ratio was significantly higher in HT and LT than in UR and CK. Only HT significantly increased soil temperature. Soil temperature could better explain R h (R 2 =0.69-0.96) than R a (R 2 =0.51-0.86). HT and LT increased Q 10 for both R a and R h , except for R h in UR. Soil moisture content (W; %) was significantly higher in HT than in other treatments, but W had limited effects on soil respiration in that rain-rich subtropical China. This result suggests that global warming alone, or in combination with clear-cutting or canopy tree thinning will markedly increase soil heterotrophic respiration and thus the total soil CO 2 emission. To get firewood for local people and to reduce soil CO 2 emissions under global warming, canopy trees are needed to be protected and understory shrubs may be allowed to be used in the subtropical China. Copyright © 2017 Elsevier B.V. All rights reserved.

Moisture Limitations Dominate the Seasonality of Heterotrophic Respiration in the Southern Hemisphere

NASA Astrophysics Data System (ADS)

Konings, A. G.; Bloom, A. A.; Liu, J.; Parazoo, N.; Schimel, D.; Bowman, K. W.

2016-12-01

Heterotrophic respiration is the dominant process causing the loss of soil organic carbon, the largest stock of carbon on earth. Temperature, soil moisture, substrate availability, and soil microbial composition can all affect the rate of heterotrophic respiration. Without isotopic or root-specific measurements, it can be difficult to separate the total soil respiration into autotrophic and heterotrophic respiration. As a result, the large-scale variability and seasonality of heterotrophic respiration remains unknown, especially outside the mid-latitudes. In this study, we use remote-sensing based observational constraints to estimate heterotrophic respiration at large scales. We combine net ecosystem exchange estimates from atmospheric inversions of the Carbon Monitoring System-Flux project (CMS-Flux) with a recently derived optimally-scaled GPP dataset based on satellite-observed solar-induced fluorescence variations to estimate total ecosystem respiration. The ecosystem respiration is then separated into autotrophic and heterotrophic components based on a spatially-varying carbon use efficiency retrieved in a model-data fusion framework (CARDAMOM). The three datasets are combined into a Bayesian framework to derive the uncertainty distribution of global heterotrophic respiration allowing only physically realistic solutions (appropriate signs for all fluxes), In most Southern Hemisphere regions where precipitation and temperature are anti-correlated (e.g. dry African woodlands, Sahel, Southern India, etc..), the seasonality of heterotrophic respiration follows precipitation, not temperature. This results in an apparent anti-correlation between heterotrophic respiration and temperature. By comparison, a data-constrained terrestrial ecosystem model that does not simulate an effect of soil moisture on heterotrophic respiration did not show this anti-correlation. Data-driven heterotrophic respiration estimates such as those presented here may be used to benchmark

30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

12. INTERIOR VIEW OF GATE OPERATOR ROOM, SHOWING SLIDES GATE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. INTERIOR VIEW OF GATE OPERATOR ROOM, SHOWING SLIDES GATE OPERATORS, LOOKING NORTHWEST. - Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates.

PubMed

Fendt, Sarah-Maria; Sauer, Uwe

2010-02-18

Depending on the carbon source, Saccharomyces cerevisiae displays various degrees of respiration. These range from complete respiration as in the case of ethanol, to almost complete fermentation, and thus very low degrees of respiration on glucose. While many key regulators are known for these extreme cases, we focus here on regulators that are relevant at intermediate levels of respiration. We address this question by linking the functional degree of respiration to transcriptional regulation via enzyme abundances. Specifically, we investigated aerobic batch cultures with the differently repressive carbon sources glucose, mannose, galactose and pyruvate. Based on 13C flux analysis, we found that the respiratory contribution to cellular energy production was largely absent on glucose and mannose, intermediate on galactose and highest on pyruvate. In vivo abundances of 40 respiratory enzymes were quantified by GFP-fusions under each condition. During growth on the partly and fully respired substrates galactose and pyruvate, several TCA cycle and respiratory chain enzymes were significantly up-regulated. From these enzyme levels and the known regulatory network structure, we determined the probability for a given transcription factor to cause the coordinated expression changes. The most probable transcription factors to regulate the different degrees of respiration were Gcr1p, Cat8p, the Rtg-proteins and the Hap-complex. For the latter three ones we confirmed their importance for respiration by quantifying the degree of respiration and biomass yields in the corresponding deletion strains. Cat8p is required for wild-type like respiration, independent of its known activation of gluconeogenic genes. The Rtg-proteins and the Hap-complex are essential for wild-type like respiration under partially respiratory conditions. Under fully respiratory conditions, the Hap-complex, but not the Rtg-proteins are essential for respiration.

Temperature response of soil respiration largely unaltered with experimental warming.

PubMed

Carey, Joanna C; Tang, Jianwu; Templer, Pamela H; Kroeger, Kevin D; Crowther, Thomas W; Burton, Andrew J; Dukes, Jeffrey S; Emmett, Bridget; Frey, Serita D; Heskel, Mary A; Jiang, Lifen; Machmuller, Megan B; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B; Reinsch, Sabine; Wang, Xin; Allison, Steven D; Bamminger, Chris; Bridgham, Scott; Collins, Scott L; de Dato, Giovanbattista; Eddy, William C; Enquist, Brian J; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R; Larsen, Klaus Steenberg; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M; Peñuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward; Reinmann, Andrew B; Reynolds, Lorien L; Schmidt, Inger K; Shaver, Gaius R; Strong, Aaron L; Suseela, Vidya; Tietema, Albert

2016-11-29

The respiratory release of carbon dioxide (CO 2 ) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

Temperature response of soil respiration largely unaltered with experimental warming

USGS Publications Warehouse

Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott; Collins, Scott L.; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Steenberg Larsen, Klaus; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Penuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward B.; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert

2016-01-01

The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

Temperature response of soil respiration largely unaltered with experimental warming

PubMed Central

Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Peñuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert

2016-01-01

The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming. PMID:27849609

Reading Gate Positions with a Smartphone

NASA Astrophysics Data System (ADS)

van Overloop, Peter-Jules; Hut, Rolf

2015-04-01

Worldwide many flow gates are built in water networks in order to direct water to appropriate locations. Most of these gates are adjusted manually by field operators of water management organizations and it is often centrally not known what the new position of the gate is. This makes centralized management of the entire water network difficult. One of the reasons why the measurement of the gate position is usually not executed, is that for certain gates it is not easy to do such a reading. Tilting weirs or radial gates are examples where operators need special equipment (measuring rod and long level) to determine the position and it could even be a risky procedure. Another issue is that once the measurement is done, the value is jotted down in a notebook and later, at the office, entered in a computer system. So the entire monitoring procedure is not real-time and prone to human errors. A new way of monitoring gate positions is introduced. It consists of a level that is attached to the gate and an app with which a picture can be taken from the level. Using dedicated pattern recognition algorithms, the gate position can be read by using the angle of the level versus reference points on the gate, the radius of that gate and the absolute level of the joint around which the gate turn. The method uses gps-localization of the smartphone to store the gate position in the right location in the central database.

Novel Quantum Dot Gate FETs and Nonvolatile Memories Using Lattice-Matched II-VI Gate Insulators

NASA Astrophysics Data System (ADS)

Jain, F. C.; Suarez, E.; Gogna, M.; Alamoody, F.; Butkiewicus, D.; Hohner, R.; Liaskas, T.; Karmakar, S.; Chan, P.-Y.; Miller, B.; Chandy, J.; Heller, E.

2009-08-01

This paper presents the successful use of ZnS/ZnMgS and other II-VI layers (lattice-matched or pseudomorphic) as high- k gate dielectrics in the fabrication of quantum dot (QD) gate Si field-effect transistors (FETs) and nonvolatile memory structures. Quantum dot gate FETs and nonvolatile memories have been fabricated in two basic configurations: (1) monodispersed cladded Ge nanocrystals (e.g., GeO x -cladded-Ge quantum dots) site-specifically self-assembled over the lattice-matched ZnMgS gate insulator in the channel region, and (2) ZnTe-ZnMgTe quantum dots formed by self-organization, using metalorganic chemical vapor-phase deposition (MOCVD), on ZnS-ZnMgS gate insulator layers grown epitaxially on Si substrates. Self-assembled GeO x -cladded Ge QD gate FETs, exhibiting three-state behavior, are also described. Preliminary results on InGaAs-on-InP FETs, using ZnMgSeTe/ZnSe gate insulator layers, are presented.

Efficient Z gates for quantum computing

NASA Astrophysics Data System (ADS)

McKay, David C.; Wood, Christopher J.; Sheldon, Sarah; Chow, Jerry M.; Gambetta, Jay M.

2017-08-01

For superconducting qubits, microwave pulses drive rotations around the Bloch sphere. The phase of these drives can be used to generate zero-duration arbitrary virtual Z gates, which, combined with two Xπ /2 gates, can generate any SU(2) gate. Here we show how to best utilize these virtual Z gates to both improve algorithms and correct pulse errors. We perform randomized benchmarking using a Clifford set of Hadamard and Z gates and show that the error per Clifford is reduced versus a set consisting of standard finite-duration X and Y gates. Z gates can correct unitary rotation errors for weakly anharmonic qubits as an alternative to pulse-shaping techniques such as derivative removal by adiabatic gate (DRAG). We investigate leakage and show that a combination of DRAG pulse shaping to minimize leakage and Z gates to correct rotation errors realizes a 13.3 ns Xπ /2 gate characterized by low error [1.95 (3 ) ×10-4] and low leakage [3.1 (6 ) ×10-6] . Ultimately leakage is limited by the finite temperature of the qubit, but this limit is two orders of magnitude smaller than pulse errors due to decoherence.

Global variability in leaf respiration in relation to climate and leaf traits

NASA Astrophysics Data System (ADS)

Atkin, Owen K.

2015-04-01

Leaf respiration plays a vital role in regulating ecosystem functioning and the Earth's climate. Because of this, it is imperative that that Earth-system, climate and ecosystem-level models be able to accurately predict variations in rates of leaf respiration. In the field of photosynthesis research, the F/vC/B model has enabled modellers to accurately predict variations in photosynthesis through time and space. By contrast, we lack an equivalent biochemical model to predict variations in leaf respiration. Consequently, we need to rely on phenomenological approaches to model variations in respiration across the Earth's surface. Such approaches require that we develop a thorough understanding of how rates of respiration vary among species and whether global environmental gradients play a role in determining variations in leaf respiration. Dealing with these issues requires that data sets be assembled on rates of leaf respiration in biomes across the Earth's surface. In this talk, I will use a newly-assembled global database on leaf respiration and associated traits (including photosynthesis) to highlight variation in leaf respiration (and the balance between respiration and photosynthesis) across global gradients in growth temperature and aridity.

Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

DOE PAGES

Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; ...

2015-10-09

Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variationmore » of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. We find these results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Finally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.« less

Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

NASA Astrophysics Data System (ADS)

Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

2015-11-01

Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.

Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration

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

Shrestha, Uttam M.; Seo, Youngho; Botvinick, Elias H.

Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variationmore » of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. We find these results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Finally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.« less

Image reconstruction in higher dimensions: myocardial perfusion imaging of tracer dynamics with cardiac motion due to deformation and respiration.

PubMed

Shrestha, Uttam M; Seo, Youngho; Botvinick, Elias H; Gullberg, Grant T

2015-11-07

Myocardial perfusion imaging (MPI) using slow rotating large field of view cameras requires spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration. In vivo, MPI contains additional degrees of freedom involving unavoidable motion of the heart due to quasiperiodic beating and the effects of respiration, which can severely degrade the quality of the images. This work develops a technique for a single photon emission computed tomography (SPECT) that reconstructs the distribution of the radiotracer concentration in the myocardium using a tensor product of different sets of basis functions that approximately describe the spatiotemporal variation of the radiotracer concentration and the motion of the heart. In this study the temporal B-spline basis functions are chosen to reflect the dynamics of the radiotracer, while the intrinsic deformation and the extrinsic motion of the heart are described by a product of a discrete set of Gaussian basis functions. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it deforms due to cardiac beating, and is displaced due to respiratory motion. These results are compared with the conventional 4D-spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. The higher dimensional reconstruction method proposed here improves bias, yet the signal-to-noise ratio (SNR) decreases slightly due to redistribution of the counts over the cardiac-respiratory gates. Additionally, there is a trade-off between the number of gates and the number of projections per gate to achieve high contrast images.

Temporal changes of soil respiration under different tree species.

PubMed

Akburak, Serdar; Makineci, Ender

2013-04-01

Soil respiration rates were measured monthly (from April 2007 to March 2008) under four adjacent coniferous plantation sites [Oriental spruce (Picea orientalis L.), Austrian pine (Pinus nigra Arnold), Turkish fir (Abies bornmulleriana L.), and Scots pine (Pinus sylvestris L.)] and adjacent natural Sessile oak forest (Quercus petraea L.) in Belgrad Forest-Istanbul/Turkey. Also, soil moisture, soil temperature, and fine root biomass were determined to identify the underlying environmental variables among sites which are most likely causing differences in soil respiration. Mean annual soil moisture was determined to be between 6.3 % and 8.1 %, and mean annual temperature ranged from 13.0°C to 14.2°C under all species. Mean annual fine root biomass changed between 368.09 g/m(2) and 883.71 g/m(2) indicating significant differences among species. Except May 2007, monthly soil respiration rates show significantly difference among species. However, focusing on tree species, differences of mean annual respiration rates did not differ significantly. Mean annual soil respiration ranged from 0.56 to 1.09 g C/m(2)/day. The highest rates of soil respiration reached on autumn months and the lowest rates were determined on summer season. Soil temperature, soil moisture, and fine root biomass explain mean annual soil respiration rates at the highest under Austrian pine (R (2) = 0.562) and the lowest (R (2) = 0.223) under Turkish fir.

Smart Adsorbents with Photoregulated Molecular Gates for Both Selective Adsorption and Efficient Regeneration.

PubMed

Cheng, Lei; Jiang, Yao; Yan, Ni; Shan, Shu-Feng; Liu, Xiao-Qin; Sun, Lin-Bing

2016-09-07

Selective adsorption and efficient regeneration are two crucial issues for adsorption processes; unfortunately, only one of them instead of both is favored by traditional adsorbents with fixed pore orifices. Herein, we fabricated a new generation of smart adsorbents through grafting photoresponsive molecules, namely, 4-(3-triethoxysilylpropyl-ureido)azobenzene (AB-TPI), onto pore orifices of the support mesoporous silica. The azobenzene (AB) derivatives serve as the molecular gates of mesopores and are reversibly opened and closed upon light irradiation. Irradiation with visible light (450 nm) causes AB molecules to isomerize from cis to trans configuration, and the molecular gates are closed. It is easy for smaller adsorbates to enter while difficult for the larger ones, and the selective adsorption is consequently facilitated. Upon irradiation with UV light (365 nm), the AB molecules are transformed from trans to cis isomers, promoting the desorption of adsorbates due to the opened molecular gates. The present smart adsorbents can consequently benefit not only selective adsorption but also efficient desorption, which are exceedingly desirable for adsorptive separation but impossible for traditional adsorbents with fixed pore orifices.

Optical XOR gate

DOEpatents

Vawter, G. Allen

2013-11-12

An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

Optical NOR gate

DOEpatents

Skogen, Erik J [Albuquerque, NM; Tauke-Pedretti, Anna [Albuquerque, NM

2011-09-06

An optical NOR gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical NOR gate utilizes two digital optical inputs and a continuous light input to provide a NOR function digital optical output. The optical NOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

Sequential interaction of chloride and proton ions with the fast gate steer the voltage-dependent gating in ClC-2 chloride channels

PubMed Central

Sánchez-Rodríguez, Jorge E; De Santiago-Castillo, José A; Contreras-Vite, Juan Antonio; Nieto-Delgado, Pablo G; Castro-Chong, Alejandra; Arreola, Jorge

2012-01-01

The interaction of either H+ or Cl− ions with the fast gate is the major source of voltage (Vm) dependence in ClC Cl− channels. However, the mechanism by which these ions confer Vm dependence to the ClC-2 Cl− channel remains unclear. By determining the Vm dependence of normalized conductance (Gnorm(Vm)), an index of open probability, ClC-2 gating was studied at different [H+]i, [H+]o and [Cl−]i. Changing [H+]i by five orders of magnitude whilst [Cl−]i/[Cl−]o = 140/140 or 10/140 mm slightly shifted Gnorm(Vm) to negative Vm without altering the onset kinetics; however, channel closing was slower at acidic pHi. A similar change in [H+]o with [Cl−]i/[Cl−]o = 140/140 mm enhanced Gnorm in a bell-shaped manner and shifted Gnorm(Vm) curves to positive Vm. Importantly, Gnorm was >0 with [H+]o = 10−10 m but channel closing was slower when [H+]o or [Cl−]i increased implying that ClC-2 was opened without protonation and that external H+ and/or internal Cl− ions stabilized the open conformation. The analysis of kinetics and steady-state properties at different [H+]o and [Cl−]i was carried out using a gating Scheme coupled to Cl− permeation. Unlike previous results showing Vm-dependent protonation, our analysis revealed that fast gate protonation was Vm and Cl− independent and the equilibrium constant for closed–open transition of unprotonated channels was facilitated by elevated [Cl−]i in a Vm-dependent manner. Hence a Vm dependence of pore occupancy by Cl− induces a conformational change in unprotonated closed channels, before the pore opens, and the open conformation is stabilized by Cl− occupancy and Vm-independent protonation. PMID:22753549

Effect of gate bias sweep rate on the threshold voltage of in-plane gate nanowire transistor

NASA Astrophysics Data System (ADS)

Liu, H. X.; Li, J.; Tan, R. R.

2018-01-01

In2O3 nanowire electric-double-layer (EDL) transistors with in-plane gate gated by SiO2 solid-electrolyte are fabricated on transparent glass substrates. The gate voltage sweep rates can effectively modulate the threshold voltage (Vth) of nanowire device. Both depletion mode and enhancement mode are realized, and the Vth shift of the nanowire transistors is estimated to be 0.73V (without light). This phenomenon is due to increased adsorption of oxygen on the nanowire surface by the slower gate voltage sweep rates. Adsorbed oxygens capture electrons and cause a surface of nanowire channel was depleted. The operation voltage of transistor was 1.0 V, because the EDL gate dielectric can lead to high gate dielectric capacitance. These transparent in-plane gate nanowire transistors are promising for “see-through” nanoscale sensors.

Development of an Advanced Respirator Fit Test Headform (Postprint)

DTIC Science & Technology

2012-11-01

needed to measure the fit of N95 filtering facepiece respirators (FFRs) for protection studies against viable airborne particles. The objective of...N95 filtering facepiece respirators (FFRs) for pro- tection studies against viable airborne particles. A Static (i.e., non-moving, non-speaking...The N95 class of filtering facepiece respirators (FFRs) is commonly used to re- duce exposure to airborne particles, including oil-free aerosols (dusts

Optimizing Controlling-Value-Based Power Gating with Gate Count and Switching Activity

NASA Astrophysics Data System (ADS)

Chen, Lei; Kimura, Shinji

In this paper, a new heuristic algorithm is proposed to optimize the power domain clustering in controlling-value-based (CV-based) power gating technology. In this algorithm, both the switching activity of sleep signals (p) and the overall numbers of sleep gates (gate count, N) are considered, and the sum of the product of p and N is optimized. The algorithm effectively exerts the total power reduction obtained from the CV-based power gating. Even when the maximum depth is kept to be the same, the proposed algorithm can still achieve power reduction approximately 10% more than that of the prior algorithms. Furthermore, detailed comparison between the proposed heuristic algorithm and other possible heuristic algorithms are also presented. HSPICE simulation results show that over 26% of total power reduction can be obtained by using the new heuristic algorithm. In addition, the effect of dynamic power reduction through the CV-based power gating method and the delay overhead caused by the switching of sleep transistors are also shown in this paper.

Quantum computing gates via optimal control

NASA Astrophysics Data System (ADS)

Atia, Yosi; Elias, Yuval; Mor, Tal; Weinstein, Yossi

2014-10-01

We demonstrate the use of optimal control to design two entropy-manipulating quantum gates which are more complex than the corresponding, commonly used, gates, such as CNOT and Toffoli (CCNOT): A two-qubit gate called polarization exchange (PE) and a three-qubit gate called polarization compression (COMP) were designed using GRAPE, an optimal control algorithm. Both gates were designed for a three-spin system. Our design provided efficient and robust nuclear magnetic resonance (NMR) radio frequency (RF) pulses for 13C2-trichloroethylene (TCE), our chosen three-spin system. We then experimentally applied these two quantum gates onto TCE at the NMR lab. Such design of these gates and others could be relevant for near-future applications of quantum computing devices.

Hybrid respiration in the denitrifying mitochondria of Fusarium oxysporum.

PubMed

Takaya, Naoki; Kuwazaki, Seigo; Adachi, Yoshiaki; Suzuki, Sawako; Kikuchi, Tomoko; Nakamura, Hiro; Shiro, Yoshitsugu; Shoun, Hirofumi

2003-04-01

Induction of the mitochondrial nitrate-respiration (denitrification) system of the fungus Fusarium oxysporum requires the supply of low levels of oxygen (O(2)). Here we show that O(2) and nitrate (NO(3)(-)) respiration function simultaneously in the mitochondria of fungal cells incubated under hypoxic, denitrifying conditions in which both O(2) and NO(3)(-) act as the terminal electron acceptors. The NO(3)(-) and nitrite (NO(2)(-)) reductases involved in fungal denitrification share the mitochondrial respiratory chain with cytochrome oxidase. F. oxysporum cytochrome c(549) can serve as an electron donor for both NO(2)(-) reductase and cytochrome oxidase. We are the first to demonstrate hybrid respiration in respiring eukaryotic mitochondria.

Signatures of Mechanosensitive Gating.

PubMed

Morris, Richard G

2017-01-10

The question of how mechanically gated membrane channels open and close is notoriously difficult to address, especially if the protein structure is not available. This perspective highlights the relevance of micropipette-aspirated single-particle tracking-used to obtain a channel's diffusion coefficient, D, as a function of applied membrane tension, σ-as an indirect assay for determining functional behavior in mechanosensitive channels. While ensuring that the protein remains integral to the membrane, such methods can be used to identify not only the gating mechanism of a protein, but also associated physical moduli, such as torsional and dilational rigidity, which correspond to the protein's effective shape change. As an example, three distinct D-versus-σ "signatures" are calculated, corresponding to gating by dilation, gating by tilt, and gating by a combination of both dilation and tilt. Both advantages and disadvantages of the approach are discussed. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Respiration in Aquatic Insects.

ERIC Educational Resources Information Center

MacFarland, John

1985-01-01

This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

Dynamic characteristics of soil respiration in Yellow River Delta wetlands, China

NASA Astrophysics Data System (ADS)

Wang, Xiao; Luo, Xianxiang; Jia, Hongli; Zheng, Hao

2018-02-01

The stable soil carbon (C) pool in coastal wetlands, referred to as "blue C", which has been extensively damaged by climate change and soil degradation, is of importance to maintain global C cycle. Therefore, to investigate the dynamic characteristics of soil respiration rate and evaluate C budgets in coastal wetlands are urgently. In this study, the diurnal and seasonal variation of soil respiration rate in the reed wetland land (RL) and the bare wetland land (BL) was measured in situ with the dynamic gas-infrared CO2 method in four seasons, and the factors impacted on the dynamic characteristics of soil respiration were investigated. The results showed that the diurnal variation of soil respiration rate consistently presented a "U" curve pattern in April, July, and September, with the maximum values at 12:00 a.m. and the minimum values at 6:00 a.m. In the same season, the diurnal soil respiration rate in RL was significantly greater than those in BL (P < 0.05). In April, July, and September, the mean diurnal soil respiration rate was 0.14, 0.42, and 0.39 μmol m-2 s-1 in RL, 0.05, 0.22, 0.13, and 0.01 μmol m-2 s-1 in BL, respectively. Soil surface temperature was the primary factor that influenced soil respiration, which was confirmed by the exponential positive correlation between the soil respiration rate and soil surface temperature in BL and RL (P < 0.05). In addition, the high salinity of soils suppressed soil respiration, confirming by the significantly negative correlation between soil respiration rate and the content of soluble salt. These results will be useful for understanding the mechanisms underlying soil respiration and elevating C sequestration potential in the coastal wetlands.

Ozone removal capability of a welding fume respirator containing activated charcoal.

PubMed

Johnston, A R; Dyrud, J F; Shih, Y T

1989-09-01

Development of air purifying respirators for protection against ozone has been slowed by concerns about oxidation of charcoal and other available sorbents. The suitability of a charcoal sorbent for low concentrations of ozone was evaluated as a part of the development of a half-mask air purifying respirator designed for welding fumes and ozone. Testing of the respirator confirmed that charcoal can be a suitable sorbent for low levels of ozone. Where the respirator is properly selected, fit tested, and worn, respirator use against welding fumes and ozone at concentrations not exceeding 10 times the permissible exposure limit had been recommended.

Development of deformable moving lung phantom to simulate respiratory motion in radiotherapy

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

Kim, Jina; Lee, Youngkyu; Shin, Hunjoo

Radiation treatment requires high accuracy to protect healthy organs and destroy the tumor. However, tumors located near the diaphragm constantly move during treatment. Respiration-gated radiotherapy has significant potential for the improvement of the irradiation of tumor sites affected by respiratory motion, such as lung and liver tumors. To measure and minimize the effects of respiratory motion, a realistic deformable phantom is required for use as a gold standard. The purpose of this study was to develop and study the characteristics of a deformable moving lung (DML) phantom, such as simulation, tissue equivalence, and rate of deformation. The rate of changemore » of the lung volume, target deformation, and respiratory signals were measured in this study; they were accurately measured using a realistic deformable phantom. The measured volume difference was 31%, which closely corresponds to the average difference in human respiration, and the target movement was − 30 to + 32 mm. The measured signals accurately described human respiratory signals. This DML phantom would be useful for the estimation of deformable image registration and in respiration-gated radiotherapy. This study shows that the developed DML phantom can exactly simulate the patient's respiratory signal and it acts as a deformable 4-dimensional simulation of a patient's lung with sufficient volume change.« less

BACTERIAL RESPIRATION OF ARSENIC AND SELENIUM. (R826105)

EPA Science Inventory

Abstract

Oxyanions of arsenic and selenium can be used in microbial anaerobic respiration as terminal electron acceptors. The detection of arsenate and selenate respiring bacteria in numerous pristine and contaminated environments and their rapid appearance in enrichme...

Synaptic behaviors of thin-film transistor with a Pt/HfO x /n-type indium-gallium-zinc oxide gate stack.

PubMed

Yang, Paul; Park, Daehoon; Beom, Keonwon; Kim, Hyung Jun; Kang, Chi Jung; Yoon, Tae-Sik

2018-07-20

We report a variety of synaptic behaviors in a thin-film transistor (TFT) with a metal-oxide-semiconductor gate stack that has a Pt/HfO x /n-type indium-gallium-zinc oxide (n-IGZO) structure. The three-terminal synaptic TFT exhibits a tunable synaptic weight with a drain current modulation upon repeated application of gate and drain voltages. The synaptic weight modulation is analog, voltage-polarity dependent reversible, and strong with a dynamic range of multiple orders of magnitude (>10 4 ). This modulation process emulates biological synaptic potentiation, depression, excitatory-postsynaptic current, paired-pulse facilitation, and short-term to long-term memory transition behaviors as a result of repeated pulsing with respect to the pulse amplitude, width, repetition number, and the interval between pulses. These synaptic behaviors are interpreted based on the changes in the capacitance of the Pt/HfO x /n-IGZO gate stack, the channel mobility, and the threshold voltage that result from the redistribution of oxygen ions by the applied gate voltage. These results demonstrate the potential of this structure for three-terminal synaptic transistor using the gate stack composed of the HfO x gate insulator and the IGZO channel layer.

Synaptic behaviors of thin-film transistor with a Pt/HfO x /n-type indium–gallium–zinc oxide gate stack

NASA Astrophysics Data System (ADS)

Yang, Paul; Park, Daehoon; Beom, Keonwon; Kim, Hyung Jun; Kang, Chi Jung; Yoon, Tae-Sik

2018-07-01

We report a variety of synaptic behaviors in a thin-film transistor (TFT) with a metal-oxide-semiconductor gate stack that has a Pt/HfO x /n-type indium–gallium–zinc oxide (n-IGZO) structure. The three-terminal synaptic TFT exhibits a tunable synaptic weight with a drain current modulation upon repeated application of gate and drain voltages. The synaptic weight modulation is analog, voltage-polarity dependent reversible, and strong with a dynamic range of multiple orders of magnitude (>104). This modulation process emulates biological synaptic potentiation, depression, excitatory-postsynaptic current, paired-pulse facilitation, and short-term to long-term memory transition behaviors as a result of repeated pulsing with respect to the pulse amplitude, width, repetition number, and the interval between pulses. These synaptic behaviors are interpreted based on the changes in the capacitance of the Pt/HfO x /n-IGZO gate stack, the channel mobility, and the threshold voltage that result from the redistribution of oxygen ions by the applied gate voltage. These results demonstrate the potential of this structure for three-terminal synaptic transistor using the gate stack composed of the HfO x gate insulator and the IGZO channel layer.

Soil Respiration in Semiarid Temperate Grasslands under Various Land Management

PubMed Central

Hou, Xiangyang; Schellenberg, Michael P.

2016-01-01

Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17μmol.m−2.s−1) and clipping (2.06μmol.m−2.s−1) than under grazing (1.65μmol.m−2.s−1) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China. PMID:26808376

Historical climate controls soil respiration responses to current soil moisture

PubMed Central

Waring, Bonnie G.; Rocca, Jennifer D.; Kivlin, Stephanie N.

2017-01-01

Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40–70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil moisture, which remain unresolved in ecosystem models. A common assumption of large-scale models is that soil microorganisms respond to moisture in the same way, regardless of location or climate. Here, we show that soil respiration is constrained by historical climate. We find that historical rainfall controls both the moisture dependence and sensitivity of respiration. Moisture sensitivity, defined as the slope of respiration vs. moisture, increased fourfold across a 480-mm rainfall gradient, resulting in twofold greater carbon loss on average in historically wetter soils compared with historically drier soils. The respiration–moisture relationship was resistant to environmental change in field common gardens and field rainfall manipulations, supporting a persistent effect of historical climate on microbial respiration. Based on these results, predicting future carbon cycling with climate change will require an understanding of the spatial variation and temporal lags in microbial responses created by historical rainfall. PMID:28559315

Microbial Iron Respiration Can Protect Steel from Corrosion

PubMed Central

Dubiel, M.; Hsu, C. H.; Chien, C. C.; Mansfeld, F.; Newman, D. K.

2002-01-01

Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration. PMID:11872499

Gating Topology of the Proton-Coupled Oligopeptide Symporters

PubMed Central

Fowler, Philip W.; Orwick-Rydmark, Marcella; Radestock, Sebastian; Solcan, Nicolae; Dijkman, Patricia M.; Lyons, Joseph A.; Kwok, Jane; Caffrey, Martin; Watts, Anthony; Forrest, Lucy R.; Newstead, Simon

2015-01-01

Summary Proton-coupled oligopeptide transporters belong to the major facilitator superfamily (MFS) of membrane transporters. Recent crystal structures suggest the MFS fold facilitates transport through rearrangement of their two six-helix bundles around a central ligand binding site; how this is achieved, however, is poorly understood. Using modeling, molecular dynamics, crystallography, functional assays, and site-directed spin labeling combined with double electron-electron resonance (DEER) spectroscopy, we present a detailed study of the transport dynamics of two bacterial oligopeptide transporters, PepTSo and PepTSt. Our results identify several salt bridges that stabilize outward-facing conformations and we show that, for all the current structures of MFS transporters, the first two helices of each of the four inverted-topology repeat units form half of either the periplasmic or cytoplasmic gate and that these function cooperatively in a scissor-like motion to control access to the peptide binding site during transport. PMID:25651061

Anomalous radiation effects in fully depleted SOI MOSFETs fabricated on SIMOX

NASA Astrophysics Data System (ADS)

Li, Ying; Niu, Guofu; Cressler, J. D.; Patel, J.; Marshall, C. J.; Marshall, P. W.; Kim, H. S.; Reed, R. A.; Palmer, M. J.

2001-12-01

We investigate the proton tolerance of fully depleted silicon-on-insulator (SOI) MOSFETs with H-gate and regular-gate structural configurations. For the front-gate characteristics, the H-gate does not show the edge leakage observed in the regular-gate transistor. An anomalous kink in the back-gate linear I/sub D/-V/sub GS/ characteristics of the fully depleted SOI nFETs has been observed at high radiation doses. This kink is attributed to charged traps generated in the bandgap at the buried oxide/silicon film interface during irradiation. Extensive two-dimensional simulations with MEDICI were used to understand the physical origin of this kink. We also report unusual self-annealing effects in the devices when they are cooled to liquid nitrogen temperature.

Polymer-electrolyte-gated nanowire synaptic transistors for neuromorphic applications

NASA Astrophysics Data System (ADS)

Zou, Can; Sun, Jia; Gou, Guangyang; Kong, Ling-An; Qian, Chuan; Dai, Guozhang; Yang, Junliang; Guo, Guang-hua

2017-09-01

Polymer-electrolytes are formed by dissolving a salt in polymer instead of water, the conducting mechanism involves the segmental motion-assisted diffusion of ion in the polymer matrix. Here, we report on the fabrication of tin oxide (SnO2) nanowire synaptic transistors using polymer-electrolyte gating. A thin layer of poly(ethylene oxide) and lithium perchlorate (PEO/LiClO4) was deposited on top of the devices, which was used to boost device performances. A voltage spike applied on the in-plane gate attracts ions toward the polymer-electrolyte/SnO2 nanowire interface and the ions are gradually returned after the pulse is removed, which can induce a dynamic excitatory postsynaptic current in the nanowire channel. The SnO2 synaptic transistors exhibit the behavior of short-term plasticity like the paired-pulse facilitation and self-adaptation, which is related to the electric double-effect regulation. In addition, the synaptic logic functions and the logical function transformation are also discussed. Such single SnO2 nanowire-based synaptic transistors are of great importance for future neuromorphic devices.

Radiation Hardened Electronics for Extreme Environments

NASA Technical Reports Server (NTRS)

Keys, Andrew S.; Watson, Michael D.

2007-01-01

The Radiation Hardened Electronics for Space Environments (RHESE) project consists of a series of tasks designed to develop and mature a broad spectrum of radiation hardened and low temperature electronics technologies. Three approaches are being taken to address radiation hardening: improved material hardness, design techniques to improve radiation tolerance, and software methods to improve radiation tolerance. Within these approaches various technology products are being addressed including Field Programmable Gate Arrays (FPGA), Field Programmable Analog Arrays (FPAA), MEMS Serial Processors, Reconfigurable Processors, and Parallel Processors. In addition to radiation hardening, low temperature extremes are addressed with a focus on material and design approaches.

BOREAS TE-2 Wood Respiration Data

NASA Technical Reports Server (NTRS)

Ryan, Michael G.; Lavigne, Michael; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

2000-01-01

The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set contains measurements of wood respiration conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

BOREAS TE-2 Foliage Respiration Data

NASA Technical Reports Server (NTRS)

Ryan, Michael G.; Hall, Forrest G. (Editor); Lavigne, Michael; Papagno, Andrea (Editor)

2000-01-01

The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set contains measurements of foliar respiration conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

49 CFR 234.223 - Gate arm.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Gate arm. 234.223 Section 234.223 Transportation... SYSTEMS Maintenance, Inspection, and Testing Maintenance Standards § 234.223 Gate arm. Each gate arm, when... maintained in a condition sufficient to be clearly viewed by approaching highway users. Each gate arm shall...

49 CFR 234.223 - Gate arm.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Gate arm. 234.223 Section 234.223 Transportation... SYSTEMS Maintenance, Inspection, and Testing Maintenance Standards § 234.223 Gate arm. Each gate arm, when... maintained in a condition sufficient to be clearly viewed by approaching highway users. Each gate arm shall...

49 CFR 234.223 - Gate arm.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Gate arm. 234.223 Section 234.223 Transportation... SYSTEMS Maintenance, Inspection, and Testing Maintenance Standards § 234.223 Gate arm. Each gate arm, when... maintained in a condition sufficient to be clearly viewed by approaching highway users. Each gate arm shall...

Glycolysis-respiration relationships in a neuroblastoma cell line.

PubMed

Swerdlow, Russell H; E, Lezi; Aires, Daniel; Lu, Jianghua

2013-04-01

Although some reciprocal glycolysis-respiration relationships are well recognized, the relationship between reduced glycolysis flux and mitochondrial respiration has not been critically characterized. We concomitantly measured the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of SH-SY5Y neuroblastoma cells under free and restricted glycolysis flux conditions. Under conditions of fixed energy demand ECAR and OCR values showed a reciprocal relationship. In addition to observing an expected Crabtree effect in which increasing glucose availability raised the ECAR and reduced the OCR, a novel reciprocal relationship was documented in which reducing the ECAR via glucose deprivation or glycolysis inhibition increased the OCR. Substituting galactose for glucose, which reduces net glycolysis ATP yield without blocking glycolysis flux, similarly reduced the ECAR and increased the OCR. We further determined how reduced ECAR conditions affect proteins that associate with energy sensing and energy response pathways. ERK phosphorylation, SIRT1, and HIF1a decreased while AKT, p38, and AMPK phosphorylation increased. These data document a novel intracellular glycolysis-respiration effect in which restricting glycolysis flux increases mitochondrial respiration. Since this effect can be used to manipulate cell bioenergetic infrastructures, this particular glycolysis-respiration effect can practically inform the development of new mitochondrial medicine approaches. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparing organic versus conventional soil management on soil respiration.

PubMed

Mátyás, Bence; Chiluisa Andrade, Maritza Elizabeth; Yandun Chida, Nora Carmen; Taipe Velasco, Carina Maribel; Gavilanes Morales, Denisse Estefania; Miño Montero, Gisella Nicole; Ramirez Cando, Lenin Javier; Lizano Acevedo, Ronnie Xavier

2018-01-01

Soil management has great potential to affect soil respiration. In this study, we investigated the effects of organic versus conventional soil management on soil respiration.  We measured the main soil physical-chemical properties from conventional and organic managed soil in Ecuador. Soil respiration was determined using alkaline absorption according to Witkamp.  Soil properties such as organic matter, nitrogen, and humidity, were comparable between conventional and organic soils in the present study, and in a further analysis there was no statically significant correlation with soil respiration. Therefore, even though organic farmers tend to apply more organic material to their fields, but this did not result in a significantly higher CO2 production in their soils in the present study.

Comparing organic versus conventional soil management on soil respiration

PubMed Central

Mátyás, Bence; Chiluisa Andrade, Maritza Elizabeth; Yandun Chida, Nora Carmen; Taipe Velasco, Carina Maribel; Gavilanes Morales, Denisse Estefania; Miño Montero, Gisella Nicole; Ramirez Cando, Lenin Javier; Lizano Acevedo, Ronnie Xavier

2018-01-01

Soil management has great potential to affect soil respiration. In this study, we investigated the effects of organic versus conventional soil management on soil respiration.  We measured the main soil physical-chemical properties from conventional and organic managed soil in Ecuador. Soil respiration was determined using alkaline absorption according to Witkamp.  Soil properties such as organic matter, nitrogen, and humidity, were comparable between conventional and organic soils in the present study, and in a further analysis there was no statically significant correlation with soil respiration. Therefore, even though organic farmers tend to apply more organic material to their fields, but this did not result in a significantly higher CO2 production in their soils in the present study. PMID:29623193

Electron transporting water-gated thin film transistors

NASA Astrophysics Data System (ADS)

Al Naim, Abdullah; Grell, Martin

2012-10-01

We demonstrate an electron-transporting water-gated thin film transistor, using thermally converted precursor-route zinc-oxide (ZnO) intrinsic semiconductors with hexamethyldisilazene (HMDS) hydrophobic surface modification. Water gated HMDS-ZnO thin film transistors (TFT) display low threshold and high electron mobility. ZnO films constitute an attractive alternative to organic semiconductors for TFT transducers in sensor applications for waterborne analytes. Despite the use of an electrolyte as gate medium, the gate geometry (shape of gate electrode and distance between gate electrode and TFT channel) is relevant for optimum performance of water-gated TFTs.

N-Channel field-effect transistors with floating gates for extracellular recordings.

PubMed

Meyburg, Sven; Goryll, Michael; Moers, Jürgen; Ingebrandt, Sven; Böcker-Meffert, Simone; Lüth, Hans; Offenhäusser, Andreas

2006-01-15

A field-effect transistor (FET) for recording extracellular signals from electrogenic cells is presented. The so-called floating gate architecture combines a complementary metal oxide semiconductor (CMOS)-type n-channel transistor with an independent sensing area. This concept allows the transistor and sensing area to be optimised separately. The devices are robust and can be reused several times. The noise level of the devices was smaller than of comparable non-metallised gate FETs. In addition to the usual drift of FET devices, we observed a long-term drift that has to be controlled for future long-term measurements. The device performance for extracellular signal recording was tested using embryonic rat cardiac myocytes cultured on fibronectin-coated chips. The extracellular cell signals were recorded before and after the addition of the cardioactive isoproterenol. The signal shapes of the measured action potentials were comparable to the non-metallised gate FETs previously used in similar experiments. The fabrication of the devices involved the process steps of standard CMOS that were necessary to create n-channel transistors. The implementation of a complete CMOS process would facilitate the integration of the logical circuits necessary for signal pre-processing on a chip, which is a prerequisite for a greater number of sensor spots in future layouts.

49 CFR 234.223 - Gate arm.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less than...

49 CFR 234.223 - Gate arm.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less than...

30 CFR 70.300 - Respiratory equipment; respirable dust.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

30 CFR 70.300 - Respiratory equipment; respirable dust.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

30 CFR 70.300 - Respiratory equipment; respirable dust.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

30 CFR 70.300 - Respiratory equipment; respirable dust.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

30 CFR 70.300 - Respiratory equipment; respirable dust.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic ECG/respirator synchronizer. 892.1970 Section 892.1970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator...

Seawater Respiration, Carbon Flux, Nutrient Retention Efficiency and Heterotrophic Energy Production in the Peruvian Upwelling

NASA Astrophysics Data System (ADS)

Packard, T. T.; Osma, N.; Fernández-Urruzola, I.; Codispoti, L. A.; Christensen, J. P.; Gómez, M.

2016-02-01

Oceanic depth profiles of seawater respiration (R) and vertical carbon flux are described by similar power functions and because they are conceptually and mathematically related, they can be calculated from one another. The maximum curvature of the respiration depth profile controls carbon flux. When the curvature is sharp, the carbon flux (FC) from the epipelagic ocean is low and the nutrient retention efficiency (NRE) is high allowing these waters to maintain high productivity. When the curvature is weak, NRE is low, seawater becomes nutrient impoverished, and productivity is reduced. This means that the attenuation of respiration in ocean water columns is critical in understanding and predicting vertical FC, the capacity of epipelagic ecosystems to retain their nutrients, and primary productivity. The new metric, NRE, is the ratio of nutrient regeneration in a seawater layer to the nutrients introduced into it. In other words, NRE = R/FC. A depth profile of FC is the integral of water column R. This relationship facilitates calculating ocean sections of FC. In a FC section across the Peru upwelling system we found a carbon flux maximum extending down to 400 m, 50 km off the Peru coast. Along this same section, by coupling respiratory electron transport system activity to heterotrophic oxidative phosphorylation, we calculated an ocean section of heterotrophic energy production (HEP). In the euphotic zone, HEP ranged from 250 to 500 J d-1 m-3. Below 200m, HEP dropped to less than 5 J d-1 m-3.

Controls on Ecosystem and Root Respiration in an Alaskan Peatland

NASA Astrophysics Data System (ADS)

McConnell, N. A.; McGuire, A. D.; Harden, J. W.; Kane, E. S.; Turetsky, M. R.

2010-12-01

Boreal ecosystems cover 14% of the vegetated surface on earth and account for 25-30% of the world’s soil carbon (C), mainly due to large carbon stocks in deep peat and frozen soil layers. While peatlands have served as historical sinks of carbon, global climate change may trigger re-release of C to the atmosphere and may turn these ecosystems into net C sources. Rates of C release from a peatland are determined by regional climate and local biotic and abiotic factors such as vegetation cover, thaw depth, and peat thickness. Soil CO2 fluxes are driven by both autotrophic (plant) respiration and heterotrophic (microbial) respiration. Thus, changes in plant and microbial activity in the soil will impact CO2 emissions from peatlands. In this study, we explored environmental and vegetation controls on ecosystem respiration and root respiration in a variety of wetland sites. The study was conducted at the Alaskan Peatland Experiment (APEX; www.uoguelph.ca/APEX) sites in the Bonanza Creek Experimental Forest located 35 km southwest of Fairbanks Alaska. We measured ecosystem respiration, root respiration, and monitored a suite of environmental variables along a vegetation and soil moisture gradient including a black spruce stand with permafrost, a shrubby site with permafrost, a tussock grass site, and a herbaceous open rich fen. Within the rich fen, we have been conducting water table manipulations including a control, lowered, and raised water table treatment. In each of our sites, we measured total ecosystem respiration using static chambers and root respiration by harvesting roots from the uppermost 20 cm and placing them in a root cuvette to obtain a root flux. Ecosystem respiration (ER) on a μmol/m2/sec basis varied across sites. Water table was a significant predictor of ER at the lowered manipulation site and temperature was a strong predictor at the control site in the rich fen. Water table and temperature were both significant predictors of ER at the raised

Calmodulin-dependent gating of Ca(v)1.2 calcium channels in the absence of Ca(v)beta subunits.

PubMed

Ravindran, Arippa; Lao, Qi Zong; Harry, Jo Beth; Abrahimi, Parwiz; Kobrinsky, Evgeny; Soldatov, Nikolai M

2008-06-10

It is generally accepted that to generate calcium currents in response to depolarization, Ca(v)1.2 calcium channels require association of the pore-forming alpha(1C) subunit with accessory Ca(v)beta and alpha(2)delta subunits. A single calmodulin (CaM) molecule is tethered to the C-terminal alpha(1C)-LA/IQ region and mediates Ca2+-dependent inactivation of the channel. Ca(v)beta subunits are stably associated with the alpha(1C)-interaction domain site of the cytoplasmic linker between internal repeats I and II and also interact dynamically, in a Ca2+-dependent manner, with the alpha(1C)-IQ region. Here, we describe a surprising discovery that coexpression of exogenous CaM (CaM(ex)) with alpha(1C)/alpha(2)delta in COS1 cells in the absence of Ca(v)beta subunits stimulates the plasma membrane targeting of alpha(1C), facilitates calcium channel gating, and supports Ca2+-dependent inactivation. Neither real-time PCR with primers complementary to monkey Ca(v)beta subunits nor coimmunoprecipitation analysis with exogenous alpha(1C) revealed an induction of endogenous Ca(v)beta subunits that could be linked to the effect of CaM(ex). Coexpression of a calcium-insensitive CaM mutant CaM(1234) also facilitated gating of Ca(v)beta-free Ca(v)1.2 channels but did not support Ca2+-dependent inactivation. Our results show there is a functional matchup between CaM(ex) and Ca(v)beta subunits that, in the absence of Ca(v)beta, renders Ca2+ channel gating facilitated by CaM molecules other than the one tethered to LA/IQ to support Ca2+-dependent inactivation. Thus, coexpression of CaM(ex) creates conditions when the channel gating, voltage- and Ca2+-dependent inactivation, and plasma-membrane targeting occur in the absence of Ca(v)beta. We suggest that CaM(ex) affects specific Ca(v)beta-free conformations of the channel that are not available to endogenous CaM.

Insulin resistance in HIV-infected youth is associated with decreased mitochondrial respiration.

PubMed

Takemoto, Jody K; Miller, Tracie L; Wang, Jiajia; Jacobson, Denise L; Geffner, Mitchell E; Van Dyke, Russell B; Gerschenson, Mariana

2017-01-02

To identify relationships between insulin resistance (IR) and mitochondrial respiration in perinatally HIV-infected youth. Case-control study. Mitochondrial respiration was assessed in perinatally HIV-infected youth in Tanner stages 2-5, 25 youth with IR (IR+) and 50 without IR (IR-) who were enrolled in the Pediatric HIV/AIDS Cohort Study. IR was defined as a homeostatic model of assessment for IR value at least 4.0. A novel, high-throughput oximetry method was used to evaluate cellular respiration in peripheral blood mononuclear cells. Unadjusted and adjusted differences in mitochondrial respiration markers between IR+ and IR- were evaluated, as were correlations between mitochondrial respiration markers and biochemical measurements. IR+ and IR- youth were similar on age, sex, and race/ethnicity. Mean age was 16.5 and 15.6 years in IR+ and IR-, respectively. The IR+ group had significantly higher mean BMI and metabolic analytes (fasting glucose, insulin, cholesterol, triglycerides, and venous lactate and pyruvate) compared with the IR-. Mitochondrial respiration markers were, on average, lower in the IR+ compared with IR-, including basal respiration (417.5 vs. 597.5 pmol, P = 0.074), ATP production (11 513 vs. 15 202 pmol, P = 0.078), proton leak (584.6 vs. 790.0 pmol, P = 0.033), maximal respiration (1815 vs. 2399 pmol, P = 0.025), and spare respiration capacity (1162 vs. 2017 pmol, P = 0.032). Nonmitochondrial respiration did not differ by IR status. The results did not change when adjusted for age. HIV-infected youth with IR have lower mitochondrial respiration markers when compared to youth without IR. Disordered mitochondrial respiration may be a potential mechanism for IR in this population.

Nonvolatile “AND,” “OR,” and “NOT” Boolean logic gates based on phase-change memory

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

Li, Y.; Zhong, Y. P.; Deng, Y. F.

2013-12-21

Electronic devices or circuits that can implement both logic and memory functions are regarded as the building blocks for future massive parallel computing beyond von Neumann architecture. Here we proposed phase-change memory (PCM)-based nonvolatile logic gates capable of AND, OR, and NOT Boolean logic operations verified in SPICE simulations and circuit experiments. The logic operations are parallel computing and results can be stored directly in the states of the logic gates, facilitating the combination of computing and memory in the same circuit. These results are encouraging for ultralow-power and high-speed nonvolatile logic circuit design based on novel memory devices.

Mobius Assembly: A versatile Golden-Gate framework towards universal DNA assembly

PubMed Central

Andreou, Andreas I.

2018-01-01

Synthetic biology builds upon the foundation of engineering principles, prompting innovation and improvement in biotechnology via a design-build-test-learn cycle. A community-wide standard in DNA assembly would enable bio-molecular engineering at the levels of predictivity and universality in design and construction that are comparable to other engineering fields. Golden Gate Assembly technology, with its robust capability to unidirectionally assemble numerous DNA fragments in a one-tube reaction, has the potential to deliver a universal standard framework for DNA assembly. While current Golden Gate Assembly frameworks (e.g. MoClo and Golden Braid) render either high cloning capacity or vector toolkit simplicity, the technology can be made more versatile—simple, streamlined, and cost/labor-efficient, without compromising capacity. Here we report the development of a new Golden Gate Assembly framework named Mobius Assembly, which combines vector toolkit simplicity with high cloning capacity. It is based on a two-level, hierarchical approach and utilizes a low-frequency cutter to reduce domestication requirements. Mobius Assembly embraces the standard overhang designs designated by MoClo, Golden Braid, and Phytobricks and is largely compatible with already available Golden Gate part libraries. In addition, dropout cassettes encoding chromogenic proteins were implemented for cost-free visible cloning screening that color-code different cloning levels. As proofs of concept, we have successfully assembled up to 16 transcriptional units of various pigmentation genes in both operon and multigene arrangements. Taken together, Mobius Assembly delivers enhanced versatility and efficiency in DNA assembly, facilitating improved standardization and automation. PMID:29293531

Mobius Assembly: A versatile Golden-Gate framework towards universal DNA assembly.

PubMed

Andreou, Andreas I; Nakayama, Naomi

2018-01-01

Synthetic biology builds upon the foundation of engineering principles, prompting innovation and improvement in biotechnology via a design-build-test-learn cycle. A community-wide standard in DNA assembly would enable bio-molecular engineering at the levels of predictivity and universality in design and construction that are comparable to other engineering fields. Golden Gate Assembly technology, with its robust capability to unidirectionally assemble numerous DNA fragments in a one-tube reaction, has the potential to deliver a universal standard framework for DNA assembly. While current Golden Gate Assembly frameworks (e.g. MoClo and Golden Braid) render either high cloning capacity or vector toolkit simplicity, the technology can be made more versatile-simple, streamlined, and cost/labor-efficient, without compromising capacity. Here we report the development of a new Golden Gate Assembly framework named Mobius Assembly, which combines vector toolkit simplicity with high cloning capacity. It is based on a two-level, hierarchical approach and utilizes a low-frequency cutter to reduce domestication requirements. Mobius Assembly embraces the standard overhang designs designated by MoClo, Golden Braid, and Phytobricks and is largely compatible with already available Golden Gate part libraries. In addition, dropout cassettes encoding chromogenic proteins were implemented for cost-free visible cloning screening that color-code different cloning levels. As proofs of concept, we have successfully assembled up to 16 transcriptional units of various pigmentation genes in both operon and multigene arrangements. Taken together, Mobius Assembly delivers enhanced versatility and efficiency in DNA assembly, facilitating improved standardization and automation.

Soil Respiration and Student Inquiry: A Perfect Match

ERIC Educational Resources Information Center

Hoyt, Catherine Marie; Wallenstein, Matthew David

2011-01-01

This activity explores the cycling of carbon between the atmosphere (primarily as CO[subscript 2]) and biomass in plants, animals, and microscopic organisms. Students design soil respiration experiments using a protocol that resembles current practice in soil ecology. Three methods for measuring soil respiration are presented. Student-derived…

30 CFR 72.700 - Respiratory equipment; respirable dust.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respiratory equipment; respirable dust. 72.700... SAFETY AND HEALTH HEALTH STANDARDS FOR COAL MINES Miscellaneous § 72.700 Respiratory equipment; respirable dust. (a) Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be made available to...

Sliding-gate valve for use with abrasive materials

DOEpatents

Ayers, Jr., William J.; Carter, Charles R.; Griffith, Richard A.; Loomis, Richard B.; Notestein, John E.

1985-01-01

The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable gates, contained in separate chambers. The upper gate provides a solids-flow control function, whereas the lower gate provides a pressure-sealing function. The lower gate is supported by means for (a) lifting that gate into sealing engagement with its seat when the gate is in its open and closed positions and (b) lowering the gate out of contact with its seat to permit abrasion-free transit of the gate between its open and closed positions. When closed, the upper gate isolates the lower gate from the solids. Because of this shielding action, the sealing surface of the lower gate is not exposed to solids during transit or when it is being lifted or lowered. The chamber containing the lower gate normally is pressurized slightly, and a sweep gas is directed inwardly across the lower-gate sealing surface during the vertical translation of the gate.

Boreal and temperate trees show strong acclimation of respiration to warming.

PubMed

Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

2016-03-31

Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

Global Soil Respiration: Interaction with Environmental Variables and Response to Climate Change

NASA Astrophysics Data System (ADS)

Jian, J.; Steele, M.

2016-12-01

Background, methods, objectivesTerrestrial ecosystems take up around 1.7 Pg C per year; however, the role of terrestrial ecosystems as a carbon sink may change to carbon source by 2050, as a result of positive feedback of soil respiration response to global warming. Nevertheless, limited evidence shows that soil carbon is decreasing and the role of terrestrial ecosystems is changing under warming. One possibility is the positive feedback may slow due to the acclimation of soil respiration as a result of decreasing temperature sensitivity (Q10) with warming. To verify and quantify the uncertainty in soil carbon cycling and feedbacks to climate change, we assembled soil respiration observations from 1961 to 2014 from 724 publications into a monthly global soil respiration database (MSRDB), which included 13482 soil respiration measurements together with 38 other ancillary measurements from 538 sites. Using this database we examined macroscale variation in the relationship between soil respiration and air temperature, precipitation, leaf area index and soil properties. We also quantified global soil respiration, the sources of uncertainty, and its feedback to warming based on climate region-oriented models with variant Q10function. Results and ConclusionsOur results showed substantial heterogeneity in the relationship between soil respiration and environmental factors across different climate regions. For example, soil respiration was strongly related to vegetation (via leaf area index) in colder regions, but not in tropical region. Only in tropical and arid regions did soil properties explain any variation in soil respiration. Global annual mean soil respiration from 1961 to 2014 was estimated to be 72.41 Pg C yr-1 based on monthly global soil respiration database, 25 Pg lower than estimated based on yearly soil respiration database. By using the variable Q10 models, we estimated that global soil respiration increased at a rate of 0.03 Pg C yr-1 from 1961 to 2014

Intelligent layered nanoflare: ``lab-on-a-nanoparticle'' for multiple DNA logic gate operations and efficient intracellular delivery

NASA Astrophysics Data System (ADS)

Yang, Bin; Zhang, Xiao-Bing; Kang, Li-Ping; Huang, Zhi-Mei; Shen, Guo-Li; Yu, Ru-Qin; Tan, Weihong

2014-07-01

DNA strand displacement cascades have been engineered to construct various fascinating DNA circuits. However, biological applications are limited by the insufficient cellular internalization of naked DNA structures, as well as the separated multicomponent feature. In this work, these problems are addressed by the development of a novel DNA nanodevice, termed intelligent layered nanoflare, which integrates DNA computing at the nanoscale, via the self-assembly of DNA flares on a single gold nanoparticle. As a ``lab-on-a-nanoparticle'', the intelligent layered nanoflare could be engineered to perform a variety of Boolean logic gate operations, including three basic logic gates, one three-input AND gate, and two complex logic operations, in a digital non-leaky way. In addition, the layered nanoflare can serve as a programmable strategy to sequentially tune the size of nanoparticles, as well as a new fingerprint spectrum technique for intelligent multiplex biosensing. More importantly, the nanoflare developed here can also act as a single entity for intracellular DNA logic gate delivery, without the need of commercial transfection agents or other auxiliary carriers. By incorporating DNA circuits on nanoparticles, the presented layered nanoflare will broaden the applications of DNA circuits in biological systems, and facilitate the development of DNA nanotechnology.DNA strand displacement cascades have been engineered to construct various fascinating DNA circuits. However, biological applications are limited by the insufficient cellular internalization of naked DNA structures, as well as the separated multicomponent feature. In this work, these problems are addressed by the development of a novel DNA nanodevice, termed intelligent layered nanoflare, which integrates DNA computing at the nanoscale, via the self-assembly of DNA flares on a single gold nanoparticle. As a ``lab-on-a-nanoparticle'', the intelligent layered nanoflare could be engineered to perform a variety of

Alterations in Respiration Rate and Glycolytic Intermediates in Wounded Sugarbeet Roots

USDA-ARS?s Scientific Manuscript database

Wounding of sugarbeet roots causes an increase in respiration rate, which contributes to postharvest sucrose losses. Although respiration is estimated to cause 60 to 80% of postharvest sucrose losses, the mechanisms that regulate respiration rate in wounded sugarbeet roots are not well know. To id...

30 CFR 71.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2012 CFR

2012-07-01

... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

30 CFR 71.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2011 CFR

2011-07-01

... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

30 CFR 71.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2014 CFR

2014-07-01

... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

30 CFR 71.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2010 CFR

2010-07-01

... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

30 CFR 71.101 - Respirable dust standard when quartz is present.

Code of Federal Regulations, 2013 CFR

2013-07-01

... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

NOTE: A feasibility study of markerless fluoroscopic gating for lung cancer radiotherapy using 4DCT templates

NASA Astrophysics Data System (ADS)

Li, Ruijiang; Lewis, John H.; Cerviño, Laura I.; Jiang, Steve B.

2009-10-01

A major difficulty in conformal lung cancer radiotherapy is respiratory organ motion, which may cause clinically significant targeting errors. Respiratory-gated radiotherapy allows for more precise delivery of prescribed radiation dose to the tumor, while minimizing normal tissue complications. Gating based on external surrogates is limited by its lack of accuracy, while gating based on implanted fiducial markers is limited primarily by the risk of pneumothorax due to marker implantation. Techniques for fluoroscopic gating without implanted fiducial markers (markerless gating) have been developed. These techniques usually require a training fluoroscopic image dataset with marked tumor positions in the images, which limits their clinical implementation. To remove this requirement, this study presents a markerless fluoroscopic gating algorithm based on 4DCT templates. To generate gating signals, we explored the application of three similarity measures or scores between fluoroscopic images and the reference 4DCT template: un-normalized cross-correlation (CC), normalized cross-correlation (NCC) and normalized mutual information (NMI), as well as average intensity (AI) of the region of interest (ROI) in the fluoroscopic images. Performance was evaluated using fluoroscopic and 4DCT data from three lung cancer patients. On average, gating based on CC achieves the highest treatment accuracy given the same efficiency, with a high target coverage (average between 91.9% and 98.6%) for a wide range of nominal duty cycles (20-50%). AI works well for two patients out of three, but failed for the third patient due to interference from the heart. Gating based on NCC and NMI usually failed below 50% nominal duty cycle. Based on this preliminary study with three patients, we found that the proposed CC-based gating algorithm can generate accurate and robust gating signals when using 4DCT reference template. However, this observation is based on results obtained from a very limited

Reversible logic gates on Physarum Polycephalum

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

Schumann, Andrew

2015-03-10

In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

Travels with Gates - August 2010

Science.gov Websites

combat floods that are affecting 14 million people. Story Biography Speeches Travels Photo Essays Gates Visits Navy Special Warefare Training More Photo Essays Gates Attends Graduation in San Diego Gates Photo Essays News Photos Week In Photos Videos DIMOC DOD/Military Seals DoD Flickr Secretary of Defense

Quantum gates with controlled adiabatic evolutions

NASA Astrophysics Data System (ADS)

Hen, Itay

2015-02-01

We introduce a class of quantum adiabatic evolutions that we claim may be interpreted as the equivalents of the unitary gates of the quantum gate model. We argue that these gates form a universal set and may therefore be used as building blocks in the construction of arbitrary "adiabatic circuits," analogously to the manner in which gates are used in the circuit model. One implication of the above construction is that arbitrary classical boolean circuits as well as gate model circuits may be directly translated to adiabatic algorithms with no additional resources or complexities. We show that while these adiabatic algorithms fail to exhibit certain aspects of the inherent fault tolerance of traditional quantum adiabatic algorithms, they may have certain other experimental advantages acting as quantum gates.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes.

PubMed

Baranov, Viktor; Lewandowski, Jörg; Krause, Stefan

2016-08-01

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m(2) was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. © 2016 The Authors.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes

PubMed Central

Krause, Stefan

2016-01-01

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. PMID:27484649

Field performance measurements of half-facepiece respirators: steel mill operations.

PubMed

Myers, W R; Zhuang, Z

1998-11-01

Ambient and in-facepiece samples to evaluate the protection provided by negative-pressure, half-facepiece respirators were collected on workers in different areas of a steel mill including a sinter plant and a basic oxygen process shop. Protection was assessed by workplace protection factors (WPF). All the in-facepiece concentrations were dramatically less than the corresponding ambient concentration levels or permissible exposure limits. The geometric mean (GM) ambient and in-facepiece concentrations of iron were found to vary among tasks. Significant differences were also found to occur between the GM ambient exposure levels in which some of the respirators were used. Significant differences in respirator performance as measured by WPF or in-facepiece iron concentration were observed among different brands of respirators. For all job classifications and at all levels of airborne exposure, the fifth percentile estimates for the WPF distributions for each brand of respirator were all greater than 20.

Oleyl group-functionalized insulating gate transistors for measuring extracellular pH of floating cells

NASA Astrophysics Data System (ADS)

Imaizumi, Yuki; Goda, Tatsuro; Toya, Yutaro; Matsumoto, Akira; Miyahara, Yuji

2016-01-01

The extracellular ionic microenvironment has a close relationship to biological activities such as by cellular respiration, cancer development, and immune response. A system composed of ion-sensitive field-effect transistors (ISFET), cells, and program-controlled fluidics has enabled the acquisition of real-time information about the integrity of the cell membrane via pH measurement. Here we aimed to extend this system toward floating cells such as T lymphocytes for investigating complement activation and pharmacokinetics through alternations in the plasma membrane integrity. We functionalized the surface of tantalum oxide gate insulator of ISFET with oleyl-tethered phosphonic acid for interacting with the plasma membranes of floating cells without affecting the cell signaling. The surface modification was characterized by X-ray photoelectron spectroscopy and water contact angle measurements. The Nernst response of -37.8 mV/pH was obtained for the surface-modified ISFET at 37 °C. The oleyl group-functionalized gate insulator successfully captured Jurkat T cells in a fluidic condition without acute cytotoxicity. The system was able to record the time course of pH changes at the cells/ISFET interface during the process of instant addition and withdrawal of ammonium chloride. Further, the plasma membrane injury of floating cells after exposure by detergent Triton™ X-100 was successfully determined using the modified ISFET with enhanced sensitivity as compared with conventional hemolysis assays.

Oleyl group-functionalized insulating gate transistors for measuring extracellular pH of floating cells

PubMed Central

Imaizumi, Yuki; Goda, Tatsuro; Toya, Yutaro; Matsumoto, Akira; Miyahara, Yuji

2016-01-01

Abstract The extracellular ionic microenvironment has a close relationship to biological activities such as by cellular respiration, cancer development, and immune response. A system composed of ion-sensitive field-effect transistors (ISFET), cells, and program-controlled fluidics has enabled the acquisition of real-time information about the integrity of the cell membrane via pH measurement. Here we aimed to extend this system toward floating cells such as T lymphocytes for investigating complement activation and pharmacokinetics through alternations in the plasma membrane integrity. We functionalized the surface of tantalum oxide gate insulator of ISFET with oleyl-tethered phosphonic acid for interacting with the plasma membranes of floating cells without affecting the cell signaling. The surface modification was characterized by X-ray photoelectron spectroscopy and water contact angle measurements. The Nernst response of −37.8 mV/pH was obtained for the surface-modified ISFET at 37 °C. The oleyl group-functionalized gate insulator successfully captured Jurkat T cells in a fluidic condition without acute cytotoxicity. The system was able to record the time course of pH changes at the cells/ISFET interface during the process of instant addition and withdrawal of ammonium chloride. Further, the plasma membrane injury of floating cells after exposure by detergent Triton™ X-100 was successfully determined using the modified ISFET with enhanced sensitivity as compared with conventional hemolysis assays. PMID:27877886

Models for Total-Dose Radiation Effects in Non-Volatile Memory

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

Campbell, Philip Montgomery; Wix, Steven D.

The objective of this work is to develop models to predict radiation effects in non- volatile memory: flash memory and ferroelectric RAM. In flash memory experiments have found that the internal high-voltage generators (charge pumps) are the most sensitive to radiation damage. Models are presented for radiation effects in charge pumps that demonstrate the experimental results. Floating gate models are developed for the memory cell in two types of flash memory devices by Intel and Samsung. These models utilize Fowler-Nordheim tunneling and hot electron injection to charge and erase the floating gate. Erase times are calculated from the models andmore » compared with experimental results for different radiation doses. FRAM is less sensitive to radiation than flash memory, but measurements show that above 100 Krad FRAM suffers from a large increase in leakage current. A model for this effect is developed which compares closely with the measurements.« less

BOREAS TE-2 Root Respiration Data

NASA Technical Reports Server (NTRS)

Ryan, Michael G.; Lavigne, Michael; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

2000-01-01

The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set includes means of tree root respiration measurements on roots having diameters ranging from 0 to 2 mm conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Measuring priming using 14C of respired CO2: effects on respiration source pools and interactions with warming

NASA Astrophysics Data System (ADS)

Hopkins, F. M.; Trumbore, S.

2011-12-01

The role of substrate availability on soil carbon turnover is a critical unknown in predicting future soil carbon stocks. Substrate composition and availability can be altered by land cover change, warming, and nitrogen deposition, which can in turn affect soil carbon stocks through the priming effect. In particular, little is understood about the interaction between warming and changing substrate concentration. We examined the interactions between global change factors and the priming effect using sucrose addition to incubations of soils from two forest Free Air CO2 Enrichment (FACE) sites (Duke and Aspen). In addition to the in situ global change manipulations conducted at these sites, the CO2 fertilization procedure over the decade-long experiment labeled soil carbon pools with fossil-derived carbon (depleted in 14C relative to the background isotope content of soil carbon), allowing us to determine the effect of priming on respiration of soil carbon substrates of different ages. Thus, we used the carbon-13 signature of sucrose-derived CO2 to account for losses of substrate C, and the carbon-14 signature to partition fluxes of soil-derived CO2 between pre-FACE (> 10 y) and FACE derived (< 10 y) carbon sources. At both sites, we observed a positive priming effect-an increase in the rate of soil carbon derived respiration due to sucrose addition. However, the effect of substrate addition on respiratory source pools, as measured by 14C of respiration, varied greatly. At Duke FACE, we observed an increase in 14C content of CO2 of primed soil carbon, whereas at Aspen, we observed no difference. The amount of CO2 released by priming increased with temperature, but was proportionally similar to the amount of increase in basal respiration rates (no differences in Q10). At Duke, both warming and priming served to increase the 14C of respiration, whereas only warming changed 14C of respiration at Aspen. Despite similar overall carbon stocks, differences in the source of

Radiation Tolerant, FPGA-Based SmallSat Computer System

NASA Technical Reports Server (NTRS)

LaMeres, Brock J.; Crum, Gary A.; Martinez, Andres; Petro, Andrew

2015-01-01

The Radiation Tolerant, FPGA-based SmallSat Computer System (RadSat) computing platform exploits a commercial off-the-shelf (COTS) Field Programmable Gate Array (FPGA) with real-time partial reconfiguration to provide increased performance, power efficiency and radiation tolerance at a fraction of the cost of existing radiation hardened computing solutions. This technology is ideal for small spacecraft that require state-of-the-art on-board processing in harsh radiation environments but where using radiation hardened processors is cost prohibitive.

Stanford, Duke, Rice,... and Gates?

ERIC Educational Resources Information Center

Carey, Kevin

2009-01-01

This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

Hysteresis in voltage-gated channels.

PubMed

Villalba-Galea, Carlos A

2017-03-04

Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

Hysteresis in voltage-gated channels

PubMed Central

2017-01-01

ABSTRACT Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels. PMID:27689426

Changes in mitochondrial respiration in the human placenta over gestation.

PubMed

Holland, Olivia J; Hickey, Anthony J R; Alvsaker, Anna; Moran, Stephanie; Hedges, Christopher; Chamley, Lawrence W; Perkins, Anthony V

2017-09-01

Placental mitochondria are subjected to micro-environmental changes throughout gestation, in particular large variations in oxygen. How placental mitochondrial respiration adapts to changing oxygen concentrations remains unexplored. Additionally, placental tissue is often studied in culture; however, the effect of culture on placental mitochondria is unclear. Placental tissue was obtained from first trimester and term (laboured and non-laboured) pregnancies, and selectively permeabilized to access mitochondria. Respirometry was used to compare respiration states and substrate use in mitochondria. Additionally, explants of placental tissue were cultured for four, 12, 24, 48, or 96 h and respiration measured. Mitochondrial respiration decreased at 11 weeks compared to earlier gestations (p = 0.05-0.001), and mitochondrial content increased at 12-13 weeks compared to 7-10 weeks (p = 0.042). In term placentae, oxidative phosphorylation (OXPHOS) through mitochondrial complex IV (p < 0.001), the relative proportion of OXPHOS CI (p < 0.001), the total capacity of the respiratory system (p = 0.003), and mitochondrial content (p < 0.001) were higher compared to first trimester. Respiration was increased (p ≤ 0.006-0.001) in laboured compared to non-laboured placenta. After four hours of culture, respiration was depressed compared to fresh tissue from the same placenta and continued to decline with time in culture. Markers of apoptosis were increased, while markers of autophagy, mitochondrial biogenesis, and mitochondrial membrane potential were decreased after four hours of culture. Respiration and mitochondrial content alter over gestation/with labour. Decreased respiration at 11 weeks and increased mitochondrial content at 12-13 weeks may relate to onset of maternal blood flow, and increased respiration as a result of labour may be an adaptation to ischaemia-reperfusion. At term, mitochondria were more susceptible to changes in respiratory function

Interpreting diel hysteresis between soil respiration and temperature

Treesearch

C. Phillips; N. Nickerson; D. Risk; B.J. Bond

2011-01-01

Increasing use of automated soil respiration chambers in recent years has demonstrated complex diel relationships between soil respiration and temperature that are not apparent from less frequent measurements. Soil surface flux is often lagged from soil temperature by several hours, which results in semielliptical hysteresis loops when surface flux is plotted as a...

Supporting aspartate biosynthesis is an essential function of respiration in proliferating cells

PubMed Central

Sullivan, Lucas B.; Gui, Dan Y.; Hosios, Aaron M.; Bush, Lauren N.; Freinkman, Elizaveta; Vander Heiden, Matthew G.

2015-01-01

Summary Mitochondrial respiration is important for cell proliferation, however the specific metabolic requirements fulfilled by respiration to support proliferation have not been defined. Here we show that a major role of respiration in proliferating cells is to provide electron acceptors for aspartate synthesis. This finding is consistent with the observation that cells lacking a functional respiratory chain are auxotrophic for pyruvate, which serves as an exogenous electron acceptor. Further, the pyruvate requirement can be fulfilled with an alternative electron acceptor, alpha-ketobutyrate, which provides cells neither carbon nor ATP. Alpha-ketobutyrate restores proliferation when respiration is inhibited, suggesting that an alternative electron acceptor can substitute for respiration to support proliferation. We find that electron acceptors are limiting for producing aspartate, and supplying aspartate enables proliferation of respiration deficient cells in the absence of exogenous electron acceptors. Together, these data argue a major function of respiration in proliferating cells is to support aspartate synthesis. PMID:26232225

Supporting Aspartate Biosynthesis Is an Essential Function of Respiration in Proliferating Cells.

PubMed

Sullivan, Lucas B; Gui, Dan Y; Hosios, Aaron M; Bush, Lauren N; Freinkman, Elizaveta; Vander Heiden, Matthew G

2015-07-30

Mitochondrial respiration is important for cell proliferation; however, the specific metabolic requirements fulfilled by respiration to support proliferation have not been defined. Here, we show that a major role of respiration in proliferating cells is to provide electron acceptors for aspartate synthesis. This finding is consistent with the observation that cells lacking a functional respiratory chain are auxotrophic for pyruvate, which serves as an exogenous electron acceptor. Further, the pyruvate requirement can be fulfilled with an alternative electron acceptor, alpha-ketobutyrate, which provides cells neither carbon nor ATP. Alpha-ketobutyrate restores proliferation when respiration is inhibited, suggesting that an alternative electron acceptor can substitute for respiration to support proliferation. We find that electron acceptors are limiting for producing aspartate, and supplying aspartate enables proliferation of respiration deficient cells in the absence of exogenous electron acceptors. Together, these data argue a major function of respiration in proliferating cells is to support aspartate synthesis. Copyright © 2015 Elsevier Inc. All rights reserved.

Benchmarking gate-based quantum computers

NASA Astrophysics Data System (ADS)

Michielsen, Kristel; Nocon, Madita; Willsch, Dennis; Jin, Fengping; Lippert, Thomas; De Raedt, Hans

2017-11-01

With the advent of public access to small gate-based quantum processors, it becomes necessary to develop a benchmarking methodology such that independent researchers can validate the operation of these processors. We explore the usefulness of a number of simple quantum circuits as benchmarks for gate-based quantum computing devices and show that circuits performing identity operations are very simple, scalable and sensitive to gate errors and are therefore very well suited for this task. We illustrate the procedure by presenting benchmark results for the IBM Quantum Experience, a cloud-based platform for gate-based quantum computing.

Respirable concrete dust--silicosis hazard in the construction industry.

PubMed

Linch, Kenneth D

2002-03-01

Concrete is an extremely important part of the infrastructure of modern life and must be replaced as it ages. Many of the methods of removing, repairing, or altering existing concrete structures have the potential for producing vast quantities of respirable dust. Since crystalline silica in the form of quartz is a major component of concrete, airborne respirable quartz dust may be produced during construction work involving the disturbance of concrete, thereby producing a silicosis hazard for exposed workers. Silicosis is a debilitating and sometimes fatal lung disease resulting from breathing microscopic particles of crystalline silica. Between 1992 and 1998, the National Institute for Occupational Safety and Health (NIOSH) made visits to construction projects where concrete was being mechanically disturbed in order to obtain data concerning respirable crystalline silica dust exposures. The construction activities studied included: abrasive blasting, concrete pavement sawing and drilling, and asphalt/concrete milling. Air samples of respirable dust were obtained using 10-mm nylon cyclone pre-separators, 37-mm polyvinyl chloride (PVC) filters, and constant-flow pumps calibrated at 1.7 L/min. In addition, high-volume respirable dust samples were obtained on 37-mm PVC filters using 1/2" metal cyclones (Sensidyne model 18) and constant-flow pumps calibrated at 9.0 L/min. Air sample analysis included total weight gain by gravimetric analysis according to NIOSH Analytical Method 600 and respirable crystalline silica (quartz and cristobalite) using x-ray diffraction, as per NIOSH Analytical Method 7500. For abrasive blasting of concrete structures, the respirable crystalline silica (quartz) concentration ranged up to 14.0 mg/m3 for a 96-minute sample resulting in an eight-hour time-weighted average (TWA) of 2.8 mg/m3. For drilling concrete highway pavement the respirable quartz concentrations ranged up to 4.4 mg/m3 for a 358-minute sample, resulting in an eight-hour TWA

Unifying Gate Synthesis and Magic State Distillation.

PubMed

Campbell, Earl T; Howard, Mark

2017-02-10

The leading paradigm for performing a computation on quantum memories can be encapsulated as distill-then-synthesize. Initially, one performs several rounds of distillation to create high-fidelity magic states that provide one good T gate, an essential quantum logic gate. Subsequently, gate synthesis intersperses many T gates with Clifford gates to realize a desired circuit. We introduce a unified framework that implements one round of distillation and multiquibit gate synthesis in a single step. Typically, our method uses the same number of T gates as conventional synthesis but with the added benefit of quadratic error suppression. Because of this, one less round of magic state distillation needs to be performed, leading to significant resource savings.

Fatal injuries in the United States involving respirators, 1984-1995.

PubMed

Suruda, Anthony; Milliken, William; Stephenson, Dale; Sesek, Richard

2003-04-01

There is little published information concerning the epidemiology of fatal injuries involving respiratory protection. We compiled a case series from U.S. Occupational Safety and Health Administration investigation reports from 1984 through 1995. For the 12-year period there were 41 incidents resulting in 45 deaths due to asphyxiation or chemical poisoning while wearing a respirator. There were 23 deaths related to airline respirators, 17 deaths involving use of negative pressure (air purifying) respirators, and 5 deaths involving self-contained breathing apparatus. Among the 23 deaths involving airline respirators, 15 were associated with compatible connection couplings for breathable air and inert gases. Three workers with beards died who wore tight-fitting respirators in an atmosphere that was immediately dangerous to life and health. Most of the fatalities involved regulatory and procedural violations, and would have been prevented by proper training and compliance with existing regulations. The information concerning the victims was limited but it did not appear that medical screening would have prevented any of the deaths.

Effect of test exercises and mask donning on measured respirator fit.

PubMed

Crutchfield, C D; Fairbank, E O; Greenstein, S L

1999-12-01

Quantitative respirator fit test protocols are typically defined by a series of fit test exercises. A rationale for the protocols that have been developed is generally not available. There also is little information available that describes the effect or effectiveness of the fit test exercises currently specified in respiratory protection standards. This study was designed to assess the relative impact of fit test exercises and mask donning on respirator fit as measured by a controlled negative pressure and an ambient aerosol fit test system. Multiple donnings of two different sizes of identical respirator models by each of 14 test subjects showed that donning affects respirator fit to a greater degree than fit test exercises. Currently specified fit test protocols emphasize test exercises, and the determination of fit is based on a single mask donning. A rationale for a modified fit test protocol based on fewer, more targeted test exercises and multiple mask donnings is presented. The modified protocol identified inadequately fitting respirators as effectively as the currently specified Occupational Safety and Health Administration (OSHA) quantitative fit test protocol. The controlled negative pressure system measured significantly (p < 0.0001) more respirator leakage than the ambient aerosol fit test system. The bend over fit test exercise was found to be predictive of poor respirator fit by both fit test systems. For the better fitting respirators, only the talking exercise generated aerosol fit factors that were significantly lower (p < 0.0001) than corresponding donning fit factors.

Tai Chi training reduced coupling between respiration and postural control.

PubMed

Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

2016-01-01

In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body's center-of-mass including those caused by spontaneous respiration. Both aging and disease increase "posturo-respiratory synchronization;" which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86 ± 5 yrs) or educational-control program (n=34, 85 ± 6 yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (p<0.001). Tai Chi training did not affect traditional parameters of standing postural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part

Tai Chi training reduced coupling between respiration and postural control

PubMed Central

Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

2015-01-01

In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body’s center-of-mass including those caused by spontaneous respiration. Both aging and disease increase “posturo-respiratory synchronization;” which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86±5yrs) or educational-control program (n=34, 85±6yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (p<0.001). Tai Chi training did not affect traditional parameters of standing postural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part

Small ecosystem engineers as important regulators of lake's sediment respiration.

NASA Astrophysics Data System (ADS)

Baranov, Victor; Lewandowski, Joerg; Krause, Stefan; Romeijn, Paul

2016-04-01

Although shallow lakes are covering only about 1.5% of the land surface of the Earth, they are responsible for sequestration of carbon amounts similar or even larger than those sequestered in all marine sediments. One of the most important drivers of the carbon sequestration in lakes is sediment respiration. Especially in shallow lakes, bioturbation, i.e. the biogenic reworking of the sediment matrix and the transport of fluids within the sediment, severely impacts on sediment respiration. Widespread freshwater bioturbators such as chironomid larvae (Diptera, Chironomidae) are building tubes in the sediment and actively pump water through their burrows (ventilation). In the present work we study how different organism densities and temperatures (5-30°C) impact on respiration rates. In a microcosm experiment the bioreactive resazurin/resorufin smart tracer system was applied for quantifying the impacts of different densities of Chironomidae (Diptera) larvae (0, 1000, 2000 larvae/m2) on sediment respiration. Tracer transformation rates (and sediment respiration) were correlated with larval densities with highest transformation rates occurring in microcosms with highest larval densities. Respiration differences between defaunated sediment and sediment with 1000 and 2000 larvae per m2 was insignificant at 5 °C, and was progressively increasing with rising temperatures. At 30 °C respiration rates of sediment with 2000 larvae per m2 was 4.8 times higher than those of defaunated sediment. We interpret this as an effect of temperature on larval metabolic and locomotory activity. Furthermore, bacterial communities are benefiting from the combination of the high water temperatures and bioirrigation as bacterial community are able to maintain high metabolic rates due to oxygen supplied by bioirrigation. In the context of global climate change that means that chironomid ecosystem engineering activity will have a profound and increasing impact on lake sediment respiration

Occupational Exposure to Respirable Crystalline Silica. Final rule.

PubMed

2016-03-25

The Occupational Safety and Health Administration (OSHA) is amending its existing standards for occupational exposure to respirable crystalline silica. OSHA has determined that employees exposed to respirable crystalline silica at the previous permissible exposure limits face a significant risk of material impairment to their health. The evidence in the record for this rulemaking indicates that workers exposed to respirable crystalline silica are at increased risk of developing silicosis and other non-malignant respiratory diseases, lung cancer, and kidney disease. This final rule establishes a new permissible exposure limit of 50 micrograms of respirable crystalline silica per cubic meter of air (50 [mu]g/m\\3\\) as an 8-hour time-weighted average in all industries covered by the rule. It also includes other provisions to protect employees, such as requirements for exposure assessment, methods for controlling exposure, respiratory protection, medical surveillance, hazard communication, and recordkeeping. OSHA is issuing two separate standards--one for general industry and maritime, and the other for construction--in order to tailor requirements to the circumstances found in these sectors.

Automated Road Closure Gate

DOT National Transportation Integrated Search

2000-05-01

This report presents the procedures involved in the research, design, construction, and testing of an Automated Road Closure Gate. The current road closure gates used in South Dakota are often unsafe and difficult to operate. This report will assist ...

Site-Directed Spin Labeling Reveals Pentameric Ligand-Gated Ion Channel Gating Motions

PubMed Central

Dellisanti, Cosma D.; Ghosh, Borna; Hanson, Susan M.; Raspanti, James M.; Grant, Valerie A.; Diarra, Gaoussou M.; Schuh, Abby M.; Satyshur, Kenneth; Klug, Candice S.; Czajkowski, Cynthia

2013-01-01

Pentameric ligand-gated ion channels (pLGICs) are neurotransmitter-activated receptors that mediate fast synaptic transmission. In pLGICs, binding of agonist to the extracellular domain triggers a structural rearrangement that leads to the opening of an ion-conducting pore in the transmembrane domain and, in the continued presence of neurotransmitter, the channels desensitize (close). The flexible loops in each subunit that connect the extracellular binding domain (loops 2, 7, and 9) to the transmembrane channel domain (M2–M3 loop) are essential for coupling ligand binding to channel gating. Comparing the crystal structures of two bacterial pLGIC homologues, ELIC and the proton-activated GLIC, suggests channel gating is associated with rearrangements in these loops, but whether these motions accurately predict the motions in functional lipid-embedded pLGICs is unknown. Here, using site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy and functional GLIC channels reconstituted into liposomes, we examined if, and how far, the loops at the ECD/TMD gating interface move during proton-dependent gating transitions from the resting to desensitized state. Loop 9 moves ∼9 Å inward toward the channel lumen in response to proton-induced desensitization. Loop 9 motions were not observed when GLIC was in detergent micelles, suggesting detergent solubilization traps the protein in a nonactivatable state and lipids are required for functional gating transitions. Proton-induced desensitization immobilizes loop 2 with little change in position. Proton-induced motion of the M2–M3 loop was not observed, suggesting its conformation is nearly identical in closed and desensitized states. Our experimentally derived distance measurements of spin-labeled GLIC suggest ELIC is not a good model for the functional resting state of GLIC, and that the crystal structure of GLIC does not correspond to a desensitized state. These findings advance our

Aerosol penetration through respirator exhalation valves.

PubMed

Bellin, P; Hinds, W C

1990-10-01

Exhalation valves are a critical component of industrial respirators. They are designed to permit minimal inward leakage of air contaminants during inhalation and provide low resistance during exhalation. Under normal conditions, penetration of aerosol through exhalation valves is minimal. The exhalation valve is, however, a vulnerable component of a respirator and under actual working conditions may become dirty or damaged to the point of causing significant leakage. Aerosol penetration was measured for normal exhalation valves and valves compromised by paint or fine copper wires on the valve seat. Penetration increased with increasing wire diameter. A wire 250 microns in diameter allowed greater than 1% penetration into the mask cavity. Dirt or paint accumulated on the exhalation valve allowed a similar level of penetration. Work rate had little effect on observed penetration. Penetration decreased significantly with increasing aerosol particle size. The amount of material on the valve or valve seat necessary for significant (greater than 0.5%) inward leakage in a half-mask respirator could be readily observed by careful inspection of the exhalation valve and its seat in good lighting conditions.