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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Burst and Transient Source Experiment (BATSE) for the Gamma Ray Observatory (GRO)

The Burst and Transient Source Experiment (BATSE) on the Gamma Ray Observatory (GRO) is expected to provide new and better observational data on bursts to test current and future models of burst sources. These data will include: (1) the celestial distribution of hundreds of burst sources over the life of the mission, (2) burst locations within several degrees, within 2 days after their occurrence, (3) observations of weaker bursts and better observations of short timescale fluctuations and spectral variations, (4) observations by a single experiment over a much larger energy range than previously available, and (5) more sensitive measurements of the spectral features which have been observed in many bursts. This paper briefly describes the GRO mission, the BATSE instrumentation and the burst observational capabilities.

Fishman, G. J.↗
DOE OSTI2022

Installation and imaging of thousands of minirhizotrons to phenotype root systems of field-grown plants

Roots are vital to plant performance because they acquire resources from the soil and provide anchorage. However, it remains difficult to assess root system size and distribution because roots are inaccessible in the soil. Existing methods to phenotype entire root systems range from slow, often destructive, methods applied to relatively small numbers of plants in the field to rapid methods that can be applied to large numbers of plants in controlled environment conditions. Much has been learned recently by extensive sampling of the root crown portion of field-grown plants. But, information on large-scale genetic and environmental variation in the size and distribution of root systems in the field remains a key knowledge gap. Minirhizotrons are the only established, non-destructive technology that can address this need in a standard field trial. Prior experiments have used only modest numbers of minirhizotrons, which has limited testing to small numbers of genotypes or environmental conditions. This study addressed the need for methods to install and collect images from thousands of minirhizotrons and thereby help break the phenotyping bottleneck in the field. Over three growing seasons, methods were developed and refined to install and collect images from up to 3038 minirhizotrons per experiment. Modifications were made to four tractors and hydraulic soil corers mounted to them. High quality installation was achieved at an average rate of up to 84.4 minirhizotron tubes per tractor per day. A set of four commercially available minirhizotron camera systems were each transported by wheelbarrow to allow collection of images of mature maize root systems at an average rate of up to 65.3 tubes per day per camera. This resulted in over 300,000 images being collected in as little as 11 days for a single experiment. The scale of minirhizotron installation was increased by two orders of magnitude by simultaneously using four tractor-mounted, hydraulic soil corers with modifications to ensure high quality, rapid operation. Image collection can be achieved at the corresponding scale using commercially available minirhizotron camera systems. Along with recent advances in image analysis, these advances will allow use of minirhizotrons at unprecedented scale to address key knowledge gaps regarding genetic and environmental effects on root system size and distribution in the field.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Testing quantum gravity using pulsed optomechanical systems

An interesting idea, dating back to Feynman [Report from Chapel Hill Conference, edited by C. M. DeWitt and D. Rickles (1957)], argues that quantum mechanics may break down for large masses if one entertains the possibility that gravity can be “classical,” thereby leading to predictions different from conventional low-energy quantum gravity. Despite the technical difficulty in testing such deviations, a large number of experimental proposals have been put forward due to the high level of fundamental interest. Here, we consider the Schrödinger-Newton (SN) theory and the correlated worldline (CWL) theory, and show that they can be distinguished from conventional quantum mechanics, as well as each other, by performing pulsed optomechanics experiments. For CWL specifically we develop a framework resembling the commonly used “Heisenberg-picture” treatment of coupled oscillators, allowing one to perform simple calculations for such systems without delving into the deeper path-integral formalism. We find that discriminating between the theories will be very difficult until experimental control over low frequency quantum optomechanical systems is pushed much further. Furthermore, the predicted departures of SN and CWL from quantum mechanics occur at the same scale, so both alternative models could in principle be probed by a single experiment.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Embedded Fiber Optic Sensors for Measuring Transient Detonation/Shock Behavior;Time-of-Arrival Detection and Waveform Determination.

The miniaturization of explosive components has driven the need for a corresponding miniaturization of the current diagnostic techniques available to measure the explosive phenomena. Laser interferometry and the use of spectrally coated optical windows have proven to be an essential interrogation technique to acquire particle velocity time history data in one- dimensional gas gun and relatively large-scale explosive experiments. A new diagnostic technique described herein allows for experimental measurement of apparent particle velocity time histories in microscale explosive configurations and can be applied to shocks/non-shocks in inert materials. The diagnostic, Embedded Fiber Optic Sensors (EFOS), has been tested in challenging microscopic experimental configurations that give confidence in the technique's ability to measure the apparent particle velocity time histories of an explosive with pressure outputs in the tenths of kilobars to several kilobars. Embedded Fiber Optic Sensors also allow for several measurements to be acquired in a single experiment because they are microscopic, thus reducing the number of experiments necessary. The future of EFOS technology will focus on further miniaturization, material selection appropriate for the operating pressure regime, and extensive hydrocode and optical analysis to transform apparent particle velocity time histories into true particle velocity time histories as well as the more meaningful pressure time histories.

Chavez, Marcus Alexander↗
NASA NTRS1994

Importance of dose-rate and cell proliferation in the evaluation of biological experimental results

The nuclei of cells within the bodies of astronauts traveling on extended missions outside the geomagnetosphere will experience single traversals of particles with high Linear Energy Transfer (LET) (e.g., one iron ion per one hundred years, on average) superimposed on a background of tracks with low LET (approximately one proton every two to three days, and one helium ion per month). In addition, some cell populations within the body will be proliferating, thus possibly providing increasing numbers of cells with 'initiated' targets for subsequent radiation hits. These temporal characteristics are not generally reproduced in laboratory experimental protocols. Implications of the differences in the temporal patterns of radiation delivery between conventionally designed radiation biology experiments and the pattern to be experienced in space are examined and the importance of dose-rate and cell proliferation are pointed out in the context of radiation risk assessment on long mission in space.

Curtis, S. B.↗
DOE OSTI2017

Can tonne-scale direct detection experiments discover nuclear dark matter?

Models of nuclear dark matter propose that the dark sector contains large composite states consisting of dark nucleons in analogy to Standard Model nuclei. We examine the direct detection phenomenology of a particular class of nuclear dark matter model at the current generation of tonne-scale liquid noble experiments, in particular DEAP-3600 and XENON1T. In our chosen nuclear dark matter scenario distinctive features arise in the recoil energy spectra due to the non-point-like nature of the composite dark matter state. We calculate the number of events required to distinguish these spectra from those of a standard point-like WIMP state with a decaying exponential recoil spectrum. In the most favourable regions of nuclear dark matter parameter space, we find that a few tens of events are needed to distinguish nuclear dark matter from WIMPs at the 3 σ level in a single experiment. Given the total exposure time of DEAP-3600 and XENON1T we find that at best a 2 σ distinction is possible by these experiments individually, while 3 σ sensitivity is reached for a range of parameters by the combination of the two experiments. We show that future upgrades of these experiments have potential to distinguish a large range of nuclear dark matter models from that of a WIMP at greater than 3 σ .

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2009

Long Term Measurement of the Vapor Pressure of Gold in the Au-C System

Incorporating the {Au(s,l) + graphite} reference in component activity measurements made with the multiple effusion-cell vapor source mass spectrometry (multicell KEMS) technique provides a fixed temperature defining ITS-90 (T(sub mp)(Au) = 1337.33K) and a systematic method to check accuracy. Over a 2 year period delta H sub(298)Au was determined by the 2nd and 3rd law methods in 25 separate experiments and were in the ranges 362.2 plus or minus 3.3 kJmol(sup -1) and 367.8 plus or minus 1.1 kJmol(sup -1), respectively. This 5 kJmol-1 discrepancy is transferred directly to the measured activities. This is unacceptable and the source of this discrepancy needs to be understood and corrected. Accepting the 2nd law value increases p(Au) by about 50 percent, brings the 2nd and 3rd law values into agreement and removes the T dependence in the 3rd law values. While compelling, there is no way to independently determine instrument sensitivities, S(sub Au), with T in a single experiment with KEMS. This lack of capability is stopping a deeper understanding of this problem. In addition, the Au-C phase diagram suggests a eutectic invariant reaction: L-Au(4.7at%C) = FCC-Au(0.08at%C) + C(graphite) at T(sub e) approximately 1323K. This high C concentration in Au(l) must reduce p(Au) in equilibrium with {Au(s,l) + graphite} and raises some critical questions about the Gibbs free energy functions of Au(s,l) and the Au fixed point (T(sub mp)(Au) = 1337.33K) which is always measured in graphite.

Copland, Evan H.↗
DOE OSTI2025

Experimental study of 53 Cr via the (𝑑, 𝑝⁢𝛾) reaction

Excited states in 53 Cr were studied via the 52 Cr ⁢(𝑑, 𝑝⁢𝛾) reaction up to the neutron-separation threshold. Proton-𝛾 angular correlations and 𝛾 decay branching ratios were measured in particle-𝛾 coincidences between the Super-Enge Split-Pole Spectrograph (SE-SPS) and CeBr 3 Array (CeBrA) demonstrator of the John D. Fox Accelerator Laboratory at Florida State University. Previous spin-parity assignments from a (𝑑,𝑝) singles experiment at the SE-SPS are supported and 𝛾-ray transitions in 53 Cr are reported. We firmly assign higher-lying excited states to 53 Cr because overlapping excited states and contaminants could be identified better due to the complementary 𝛾-decay information. We also correct some of the previously reported excitation energies and present a reanalysis of previously measured 52 Cr (𝑑, 𝑝)⁢ 53 Cr angular distributions guided by the complementary 𝛾-ray information. Based on this reanalysis, the fragmentation of the neutron 2⁢𝑝 3/2 , 2⁢𝑝 1/2 , 1⁢𝑓 5/2 , 1⁢𝑔 9/2 , and 2⁢𝑑 5/2 single-particle strengths is reassessed for 53 Cr. Here, a comparison to the corresponding strengths in 55 Fe is presented.

39 ≤ A ≤ 58↗
DOE OSTI2016

Effects of molecular confinement and crowding on horseradish peroxidase kinetics using a nanofluidic gradient mixer

Here, we studied the effects of molecular confinement and crowding on enzyme kinetics at length scales and under conditions similar to those found in biological cells. These experiments were carried out using a nanofluidic network of channels constituting a nanofluidic gradient mixer, providing the basis for measuring multiple experimental conditions simultaneously. Furthermore, the 100 nm × 40 μm nanochannels were wet etched directly into borosilicate glass, then annealed and characterized with fluorescein emission prior to kinetic measurements. The nanofluidic gradient mixer was then used to measure the kinetics of the conversion of the horseradish peroxidase (HRP)-catalyzed conversion of non-fluorescent Amplex Red (AR) to the fluorescent product resorufin in the presence of hydrogen peroxide (H 2 O 2 ). The design of the gradient mixer allows reaction kinetics to be studied under multiple (five) unique solution compositions in a single experiment. In order to characterize the efficiency of the device the effects of confinement on HRP-catalyzed AR conversion kinetics were studied by varying the starting ratio of AR : H 2 O 2 . Equimolar concentrations of Amplex Red and H 2 O 2 yielded the highest reaction rates followed by 2 : 1, 1 : 2, 5 : 1, and finally 1 : 5 [AR] : [H 2 O 2 ]. Under all conditions, initial reaction velocities were decreased by excess H 2 O 2 . Crowding effects on kinetics were studied by increasing solution viscosity in the nanochannels in the range 1.0–1.6 cP with sucrose. Increasing the solution viscosities in these confined geometries decreases the initial reaction velocity at the highest concentration from 3.79 μM min -1 at 1.00 cP to 0.192 μM min -1 at 1.59 cP. Variations in reaction velocity are interpreted in the context of models for HRP catalysis and for molecular crowding.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2021

Novel Ways to use the International Spacer Station as an Exploration Analog: International Progress in Planning "ISS4Mars"

In October 2020, International Space Station (ISS) Partner Agencies held a set of international workshops to solicit and develop creative and forward-looking ideas for using the ISS as an analog for preparation for Mars missions during its 3rd decade of operations. The workshops brought together participants from nine international space agencies or organizations, with stakeholders consisting of research managers, discipline experts, technology developers, flight physicians, flight operators, and astronauts. Breakout meetings and brainstorming sessions were conducted focusing on the following topics: Critical hazards and countermeasures for the transit to Mars; gravity transitions and early surface operations; environmental control and life support systems; food systems; human microbiome, microbial monitoring, and planetary protection; medical operations for Mars missions; isolation and confinement; autonomous systems and crew-centered autonomy; and communications delay effects on operations. In many cases the scenarios and approaches identified were compelling but challenging to implement under the current utilization structure used to manage the ISS for experiments. Following the series of workshops, a team of utilization leaders across the ISS partnership worked to compile the workshop recommendations and extract a set of use-cases with their prerequisites and constraints. The work considered the following aspects: what can be effectively done on ISS; which new technologies, approaches and scenarios are feasible; what alternatives could be considered; and what steps should be taken to enable integrated testing and future use of ISS as an analog for Mars missions. The final report will be published so that the use cases can be considered in each agency’s strategic planning processes. This paper will cover the process of international assessment in detail and how this process has influenced and broadened the vision of ISS utilization beyond single experiments to integrated studies and testing for future Mars missions. This approach to international collaboration informs both the next decade of international exploration research on the ISS and advancement of its utilization as an analog for deep space missions. For many of the participating partners, it also helps to frame the strategy for human research in Artemis as we begin planning for human missions to the moon. We conclude with a summary of the progress on the actions in the report and the additional implementation discussions that have occurred across the partnership.

Julie A Robinson↗
DOE OSTI2018

Flexible Learning-Free Segmentation and Reconstruction of Neural Volumes

Imaging is a dominant strategy for data collection in neuroscience, yielding stacks of images that often scale to gigabytes of data for a single experiment. Machine learning algorithms from computer vision can serve as a pair of virtual eyes that tirelessly processes these images, automatically detecting and identifying microstructures. Unlike learning methods, our Flexible Learning-free Reconstruction of Imaged Neural volumes (FLoRIN) pipeline exploits structure-specifc contextual clues and requires no training. This approach generalizes across diferent modalities, including serially-sectioned scanning electron microscopy (sSEM) of genetically labeled and contrast enhanced processes, spectral confocal refectance (SCoRe) microscopy, and high-energy synchrotron X-ray microtomography (μCT) of large tissue volumes. We deploy the FLoRIN pipeline on newly published and novel mouse datasets, demonstrating the high biological fdelity of the pipeline’s reconstructions. FLoRIN reconstructions are of sufcient quality for preliminary biological study, for example examining the distribution and morphology of cells or extracting single axons from functional data. Compared to existing supervised learning methods, FLoRIN is one to two orders of magnitude faster and produces high-quality reconstructions that are tolerant to noise and artifacts, as is shown qualitatively and quantitatively.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Publisher Correction: Flexible Learning-Free Segmentation and Reconstruction of Neural Volumes

Imaging is a dominant strategy for data collection in neuroscience, yielding stacks of images that often scale to gigabytes of data for a single experiment. Machine learning algorithms from computer vision can serve as a pair of virtual eyes that tirelessly processes these images, automatically detecting and identifying microstructures. Unlike learning methods, our Flexible Learning-free Reconstruction of Imaged Neural volumes (FLoRIN) pipeline exploits structure-specific contextual clues and requires no training. This approach generalizes across different modalities, including serially-sectioned scanning electron microscopy (sSEM) of genetically labeled and contrast enhanced processes, spectral confocal reflectance (SCoRe) microscopy, and high-energy synchrotron X-ray microtomography (μCT) of large tissue volumes. We deploy the FLoRIN pipeline on newly published and novel mouse datasets, demonstrating the high biological fidelity of the pipeline’s reconstructions. FLoRIN reconstructions are of sufficient quality for preliminary biological study, for example examining the distribution and morphology of cells or extracting single axons from functional data. Compared to existing supervised learning methods, FLoRIN is one to two orders of magnitude faster and produces high-quality reconstructions that are tolerant to noise and artifacts, as is shown qualitatively and quantitatively.

Shahbazi, Ali↗
DOE OSTI2018

Updated global analysis of neutrino oscillations in the presence of eV-scale sterile neutrinos

Here, we discuss the possibility to explain the anomalies in short-baseline neutrino oscillation experiments in terms of sterile neutrinos. We work in a 3 + 1 framework and pay special attention to recent new data from reactor experiments, IceCube and MINOS+. We find that results from the DANSS and NEOS reactor experiments support the sterile neutrino explanation of the reactor anomaly, based on an analysis that relies solely on the relative comparison of measured reactor spectra. Global data from the ν$_{e}$ disappearance channel favour sterile neutrino oscillations at the 3σ level with Δm$_{41}^{2}$ ≈1.3 eV$^{2}$ and |U$_{e4}$| ≈ 0.1, even without any assumptions on predicted reactor fluxes. In contrast, the anomalies in the ν$_{e}$ appearance channel (dominated by LSND) are in strong tension with improved bounds on ν$_{μ}$ disappearance, mostly driven by MINOS+ and IceCube. Under the sterile neutrino oscillation hypothesis, the p-value for those data sets being consistent is less than 2.6 × 10$^{-6}$. Therefore, an explanation of the LSND anomaly in terms of sterile neutrino oscillations in the 3 + 1 scenario is excluded at the 4.7σ level. This result is robust with respect to variations in the analysis and used data, in particular it depends neither on the theoretically predicted reactor neutrino fluxes, nor on constraints from any single experiment. Irrespective of the anomalies, we provide updated constraints on the allowed mixing strengths |U$_{α4}$| (α = e, μ, τ ) of active neutrinos with a fourth neutrino mass state in the eV range.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

A Miniature Multilevel Structures for Lossless Ion Manipulations Ion Mobility Spectrometer with Wide Mobility Range Separation Capabilities

Here, ion mobility spectrometry employing structures for lossless ion manipulations (SLIM-IMS) is an attractive gas-phase separation technique due to its ability to achieve unprecedented effective ion path lengths (>1 km) and IMS resolving powers in a small footprint. The emergence of multilevel SLIM technology, where ions are transferred between vertically stacked SLIM electrode surfaces, has subsequently allowed for ultralong single pass path lengths (>40 m) to be achieved, enabling ultrahigh resolution IMS measurements to be performed over the entire mobility range in a single experiment. The implementation of multiple SLIM levels requires very little additional space for the SLIM system, and we developed a miniature SLIM module (miniSLIM) based on multilevel SLIM technology and report the performance here. The module is 11.1 cm x 6.7 cm x 1.4 cm (L x W x H) and consists of three SLIM levels totaling 1-meter path length. Ion trajectory simulations were used to optimize the SLIM board spacings and SLIM board thicknesses of the miniSLIM IMS system. Methods of efficiently transferring ions between SLIM levels were examined and a new approach using asymmetric traveling waves (TWs) was developed and implemented in the miniSLIM. We experimentally characterized the performance of the --meter multilevel miniSLIM IMS-MS relative to a drift tube IM--MS using an Agilent tuning mixture and tetraalkylammonium cations. The 1-meter miniSLIM achieved a resolving power of up to 131 (CCS/ΔCCS), ~1.5x higher than achievable with a 78 cm path length drift tube IMS, and successfully transmitted the entire ion mobility range in a single separation. We also demonstrated the miniSLIM’s performance as a standalone IMS system (i.e., without MS), showing baseline separation between Agilent tuning mixture cations with the full mobility range observed, and a standard peptide mixture with different charge states readily differentiated. Overall the miniSLIM provides a compact alternative to high performance IMS instruments possessing similar path lengths.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Oxidative Stress and Skeletal Health with Low-Dose, Low-LET (Linear Energy Transfer) Ionizing Radiation

We performed in vivo and in vitro experiments to accomplish the following specific aims of this project: 1) determine if low dose, low LET radiation affects skeletal remodeling at structural, cellular and molecular levels and 2) determine if low dose, low LET radiation modulates skeletal health during aging via oxidative mechanisms. A third aim is supported by NASA supplement to this DOE grant focusing on the influence of high LET radiation on bone. A series of experiments were conducted at the NASA Space Radiation Laboratory at Brookhaven, NSRL-BNL, using iron (56Fe) or a sequential exposure to protons / iron / protons, and separate experiments at NASA Ames Research Center (ARC) using 137Cs. The following provides a summary of key findings. (1) Exposure of nine-week old female mice to priming doses of gamma radiation (10cGy x 5) did not significantly affect bone volume/total volume (BV/TV) or microarchitecture as analyzed by 3D microcomputed tomography. As expected, exposure to the challenge dose of 2 Gy gamma irradiation resulted in significant decreases in BV/TV. The priming dose combined with the 2Gy challenge dose had no further effect on BV/TV compared to challenge dose alone, with the sole exception of the Structural Model Index (SMI). SMI reflects the ratio of rods-to-plates in cancellous bone tissue, such that higher SMI values indicate a tendency toward a weaker structure compared to lower SMI values. Mice treated with both priming and challenge dose had 25% higher SMI values compared to sham-irradiated controls and 7% higher values compared to mice treated with the challenge dose alone. Thus, although this priming regimen had relatively modest effects on cancellous tissue, the difference in SMI suggests this fractionated priming doses have adverse, rather than beneficial, effects on bone structure. (2) In 10-week old male mice, a single exposure to 100cGy of 137Cs reduces trabecular bone number and connectivity density by 20% and 36% respectively one month after irradiation (IR). At four months post-IR, these animals were comparable to sham-treated controls with regards to the abovementioned structural parameters. Irradation at 1 or 10 cGy did not result in any significant changes in bone structural parameters. (3) Irradiation of 16-wk old male mice with high doses of 56Fe or proton (50 or 200cGy), but not at low doses (5 or 10cGy), showed a similar loss of cancellous BV/TV and trabecular number at five weeks post-IR. (4) Age-related bone loss overtook acute radiation-induced decrements in bone structure within four months post-IR with 100 cGy gamma and 12 months post-IR with 200 cGy iron. Transgenic mice globally overexpressing human catalase gene in mitochondria did not exhibit cancellous bone loss as assessed at four month post-IR with 10 cGy proton, 50 cGy iron, or in combination. (5) The cellular and molecular mechanisms responsible for loss of bone with radiation are mediated primarily through increased osteoclastogenesis. Our data provide evidence that there are increases in gene expression of TNF alpha and MCP1 in the bone marrow cells 24 hours post-IR and of osteoclastogenic differentiation factor RANKL by day 3. These cytokines in the marrow may stimulate mature osteoclasts or drive osteoclastogenesis from precursors. (6) Osteoblastogenesis from marrow progenitors evaluated ex vivo decreased following whole body 56Fe irradiation at a dose threshold between 20 and 50 cGy whereas osteoclastogenesis ex vivo increased with doses as low as 10cGy two days post-IR of mice. However, the latter finding was not observed in more than a single experiment. (7) Gamma irradiation of cells in vitro requires relatively high doses (200cGy) to disturb normal osteoblastogenesis and osteoclastogenesis as evidenced by decrements in mineralized nodule formation, osteoclast counts, and expression of osteoblast related genes such as runx2, col1a1. (8) We also investigated the effect of antioxidants on osteoblastogenesis following low dose in vitro gamma irradiation (15cGy) on day four bone marrow stromal cell cultures. Superoxide dismutase (SOD) was added to the cell culture medium for 2 or 3 days post-irradiation and cell colonies were counted on days 7 and 10. SOD treatment increased cell growth as measured by DNA content and colony forming units (CFU) in both irradiated cells and 0 cGy control groups. However, low dose radiation of 15cGy abolished SOD stimulatory effects on cell growth and CFU number. These results suggest that exogenous SOD increases osteoblast cell growth and colony formation and that low-dose radiation (15cGy) can interfere with the antioxidant effects. In summary, our findings indicate that acute, whole body irradiation at high doses (50-200 cGy) results in prompt tissue degradation and bone loss. Lower doses (<50 cGy) do not cause bone structural deterioration but may deplete stem/progenitor cell pools in the bone marrow.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

A Review on Quantitative Multiplexed Proteomics

Over the last few decades, mass spectrometry-based proteomics has become an increasingly powerful tool that is now able to routinely detect and quantify thousands of proteins. A major advance for global protein quantification was the introduction of isobaric tags, which in a single experiment enable the global quantification of proteins across multiple samples. We refer to these methods as multiplexed proteomics. We discuss the principles, advantages, and drawbacks of various multiplexed proteomics techniques, and compare them to alternative approaches. We discuss how the emerging combination of multiplexing with targeted proteomics might enable the reliable and high-quality quantification of very low-abundance proteins across multiple conditions. We suggest that fusing multiplexed proteomics with data-independent acquisition approaches might enable the comparison of hundreds of different samples without missing values while maintaining the superb measurement precision and accuracy obtainable with isobaric tag quantification.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Simultaneous determination of CKM angle γ and charm mixing parameters

A combination of measurements sensitive to the CP violation angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle and to the charm mixing parameters that describe oscillations between D 0 and $ \overline{D} $ 0 mesons is performed. Results from the charm and beauty sectors, based on data collected with the LHCb detector at CERN’s Large Hadron Collider, are combined for the first time. This method provides an improvement on the precision of the charm mixing parameter y by a factor of two with respect to the current world average. The charm mixing parameters are determined to be $ x=\left({0.400}_{-0.053}^{+0.052}\right)\% $ and y = $ \left({0.630}_{-0.030}^{+0.033}\right)\% $. The angle γ is found to be γ = ($ 65.4_{-4.2}^{+3.8} $)° and is the most precise determination from a single experiment.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Electron Transfer Dissociation of All Ions at All Times, MS{sup ETD}, in a Quadrupole Time-of-Flight (Q-ToF) Mass Spectrometer

Data-independent mass spectral acquisition is particularly powerful when combined with ultra-performance liquid chromatography (LC) that provides excellent separation of most components present in a given sample. Data-independent analysis (DIA) consists of alternating full MS scans and scans with fragmentation of all ions within a selected m/z range, providing precursor masses and structure information, respectively. Fragmentation spectra are acquired either by sequential isolation and fragmentation of sliding m/z ranges or fragmenting all ions entering the MS instrument with no ion isolation, termed broadband DIA. Previously, broadband DIA has only been possible using collision induced dissociation (CID). Here, we report the use of electron transfer dissociation (ETD) as the fragmentation technique in broadband DIA instead of traditional collision induced dissociation (CID) during MS{sup E}. In this approach, which we refer to as MS{sup ETD}, we implement the inherent benefits provided by ETD, such as discrimination of leucine and isoleucine, in a DIA setup. The combination of DIA analysis and ETD fragmentation with supplemental CID energy provides a powerful platform to obtain information on all precursors and their sequence from a single experiment. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗