Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “MASS SPECTRA”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Search for resonant and nonresonant new phenomena in high-mass dilepton final states at $\sqrt{s}$ = 13 TeV

A search is presented for physics beyond the standard model (SM) using electron or muon pairs with high invariant mass. A data set of proton-proton collisions collected by the CMS experiment at the LHC at √s = 13 TeV from 2016 to 2018 corresponding to a total integrated luminosity of up to 140 fb -1 is analyzed. No significant deviation is observed with respect to the SM background expectations. Upper limits are presented on the ratio of the product of the production cross section and the branching fraction to dileptons of a new narrow resonance to that of the Z boson. These provide the most stringent lower limits to date on the masses for various spin-1 particles, spin-2 gravitons in the Randall-Sundrum model, as well as spin-1 mediators between the SM and dark matter particles. Lower limits on the ultraviolet cutoff parameter are set both for four-fermion contact interactions and for the Arkani-Hamed, Dimopoulos, and Dvali model with large extra dimensions. Lepton flavor universality is tested at the TeV scale for the first time by comparing the dimuon and dielectron mass spectra. No significant deviation from the SM expectation of unity is observed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Disorder and mimesis at hadron colliders

We discuss how systems with a large number of degrees of freedom and disorder in their mass matrix can play a role in particle physics. We derive results on their mass spectra using, where applicable, QFT techniques. We study concrete realizations of these scenarios in the context of the LHC and HL-LHC, showing that collider events with a large number of soft b-quark jets can be common. Such final states can hide these models from current searches at the LHC. This motivates the ongoing effort aimed at lowering trigger thresholds and expanding data scouting.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Dark matter, sparticle spectroscopy and muon (g - 2) in SU(4) c × SU(2) L × SU(2) R

We explore the sparticle mass spectra including LSP dark matter within the framework of supersymmetric SU(4) c × SU(2) L × SU(2) R (422) models, taking into account the constraints from extensive LHC and cold dark matter searches. The soft supersymmetry-breaking parameters at MGUT can be non-universal, but consistent with the 422 symmetry. We identify a variety of coannihilation scenarios compatible with LSP dark matter, and study the implications for future supersymmetry searches and the ongoing muon g-2 experiment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Building bases of loop integrands

We describe a systematic approach to the construction of loop-integrand bases at arbitrary loop-order, sufficient for the representation of general quantum field theories. We provide a graph-theoretic definition of ‘power-counting’ for multi-loop integrands beyond the planar limit, and show how this can be used to organize bases according to ultraviolet behavior. This allows amplitude integrands to be constructed iteratively. We illustrate these ideas with concrete applications. In particular, we describe complete integrand bases at two loops sufficient to represent arbitrary-multiplicity amplitudes in four (or fewer) dimensions in any massless quantum field theory with the ultraviolet behavior of the Standard Model or better. We also comment on possible extensions of our framework to arbitrary (including regulated) numbers of dimensions, and to theories with arbitrary mass spectra and charges. At three loops, we describe a basis sufficient to capture all ‘leading-(transcendental-)weight’ contributions of any four-dimensional quantum theory; for maximally supersymmetric Yang-Mills theory, this basis should be sufficient to represent all scattering amplitude integrands in the theory — for generic helicities and arbitrary multiplicity.

1/NExpansion↗
DOE OSTI2016

A tale of twin Higgs: natural twin two Higgs doublet models

In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit Z 2 breaking term. Introducing additional twin Higgs could accommodate spontaneous Z 2 breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and Z 2 symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit Z 2 breaking, radiative Z 2 breaking, tadpole-induced Z 2 breaking, and quartic-induced Z 2 breaking. Finally, we investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Synthesis of new 1-benzyl tetrahydropyridin-4-ylidene piperidinium salts and their antiplasmodial and antitrypanosomal activities

Our last study revealed the distinct antiplasmodial and antitrypanosomal activities of 1-benzyl tetrahydropyridin-4-ylidene pyrrolidinium salts. Therefore, we prepared a series of new 1-benzyl tetrahydropyridin-4-ylidene ammonium salts with an alternative amino residue and varying substitution patterns at the benzyl group to investigate the influence of these modifications on the biological activities. All new compounds were characterized by spectroscopic methods like ultraviolet, infrared, nuclear magnetic resonance, as well as high- resolution mass spectra. They were tested for their activities against Plasmodium falciparum and Trypanosoma brucei rhodesiense as well as for their cytotoxicity against L6 cells using microplate assays. The results show that the structure of the amino residue as well as the substitution pattern of the benzyl group influences the biological activities distinctly. Physicochemical parameters are calculated and structure–activity relationships are discussed.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Synthesis, molecular docking, and apoptogenic efficacy of novel N-heterocycle analogs to target B-cell lymphoma 2/X-linked inhibitors of apoptosis proteins to regress melanoma

The novel series of piperidine conjugated benzophenone analogs with amide link 11a–l were synthesized in a multistep process. The structures of these compounds were confirmed by IR, {sup 1}H, {sup 13}C, NMR, and mass spectra and also by elemental analyses. The newly synthesized molecules were screened for selectivity against cancers of different origin through cell based assay system using B16F10, A375, A549, HepG2, ACHN, and MCF7 cells. The results postulated that compound 11f with two bromo groups at the para position in rings A and E and two methyl groups at ortho position in rings B and D evokes target specific action against melanoma highlighting the importance of substituted groups. Down the line studies further inferred compound 11f evokes the apoptotic cellular event leading to cell death. Investigation of eventual mechanism revealed that compound 11f turned out to be a dual inhibitor of B-cell lymphoma-2 and X-linked inhibitors of apoptosis causing the up regulation of Bax and Bad. Further, the antiproliferative effects were mimicked in murine melanoma with similar mechanisms. Molecular docking experiments further confirmed that compound 11f possessed a superior affinity for of B-cell lymphoma-2 and X-linked inhibitors of apoptosis through strong hydrogen bonds. The study implies the identification of compound 11f with selective target against melanoma by inducing apoptogenic effect, which could be the future hope for the treatment of skin cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Synthesis and bioassay of a new class of disubstituted 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazoles

A new class of aroylethenesulfonylmethyl styryl oxadiazoles/thiadiazoles/triazoles and arylsulfonylethenesulfonylmethyl styryl oxadiazoles/thiadiazoles/triazoles were synthesized from the synthetic intermediates E-aroylethenesulfonylacetic acid methyl ester, E-arylsulfonylethenesulfonylacetic acid methyl ester and substituted cinnamic acids adopting conventional and ultrasonication methodologies. All the synthesized compounds were obtained in higher yields and in shorter reaction times in ultrasound irradiation method when compared with conventional method. The structures of all the compounds were characterized by IR, {sup 1}H NMR, {sup 13}C NMR and mass spectra. All the title compounds were tested for antimicrobial activity. The arylsulfonylethenesulfonylmethyl styryl azoles displayed higher antimicrobial activity than the aroylethenesulfonylmethyl styryl azoles. The compounds having triazole moiety showed greater activity than those with oxadiazole and thiadiazole. Amongst all the tested compounds unsubstituted and chloro substituted arylsulfonylethenesulfonyl methyl styryl triazoles are identified as potential antimicrobial agents particularly against B. subtilis and P.chrysogenum. .

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

A Skyline Plugin for Pathway-Centric Data Browsing

For targeted proteomics to be broadly adopted in biological laboratories as a routine experimental protocol, wet-bench biologists must be able to approach SRM assay design in the same way they approach biological experimental design. Most often, biological hypotheses are envisioned in a set of protein interactions, networks and pathways. We present a plugin for the popular Skyline tool that presents public mass spectrometry data in a pathway-centric view to assist users in browsing available data and determining how to design quantitative experiments. Selected proteins and their underlying mass spectra are imported to Skyline for further assay design (transition selection). The same plugin can be used for hypothesis-drive DIA data analysis, again utilizing the pathway view to help narrow down the set of proteins which will be investigated. The plugin is backed by the PNNL Biodiversity Library, a corpus of 3 million peptides from >100 organisms, and the draft human proteome. Users can upload personal data to the plugin to use the pathway navigation prior to importing their own data into Skyline.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Stable Isotope Labeling for Improved Comparative Analysis of RNA Digests by Mass Spectrometry

Even with the advent of high throughput methods to detect modified ribonucleic acids (RNAs), mass spectrometry remains a reliable method to detect, characterize, and place post-transcriptional modifications within an RNA sequence. Here we have developed a stable isotope labeling comparative analysis of RNA digests (SIL-CARD) approach, which improves upon the original {sup 18}O/{sup 16}O labeling CARD method. Like the original, SIL-CARD allows sequence or modification information from a previously uncharacterized in vivo RNA sample to be obtained by direct comparison with a reference RNA, the sequence of which is known. This reference is in vitro transcribed using a {sup 13}C/{sup 15}N isotopically enriched nucleoside triphosphate (NTP). The two RNAs are digested with an endonuclease, the specificity of which matches the labeled NTP used for transcription. As proof of concept, several transfer RNAs (tRNAs) were characterized by SIL-CARD, where labeled guanosine triphosphate was used for the reference in vitro transcription. RNase T1 digestion products from the in vitro transcript will be 15 Da higher in mass than the same digestion products from the in vivo tRNA that are unmodified, leading to a doublet in the mass spectrum. Singlets, rather than doublets, arise if a sequence variation or a post-transcriptional modification is present that results in a relative mass shift different from 15 Da. Moreover, the use of the in vitro synthesized tRNA transcript allows for quantitative measurement of RNA abundance. Overall, SIL-CARD simplifies data analysis and enhances quantitative RNA modification mapping by mass spectrometry. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

A W-Geometry Ortho-TOF MS with High Resolution and Up to 100% Duty Cycle for MS/MS

Orthogonal injection time-of-flight (orthoTOF) mass spectrometry (MS) is the most prevalent form of TOFMS, owing to its greater control over incoming ion energy, the ability to correct for aberrations in incoming ion velocity and position, and its ability to provide an entire mass spectrum within a single scan. However, the duty cycle of orthoTOFMS is low compared with scanning analyzers, which can have 100% duty cycle when measuring a single type of ion. Typical duty cycles for orthoTOFMS range from 1% to 30%, depending on instrument geometry. Generally, as instrument resolution increases, duty cycle decreases. Additionally, the greatest duty cycle is achieved for the highest m/z ion recorded in the spectrum, and decreases for all other ions as a function of m/z. In a prior publication [Loboda, A.V.; Chernushevich, I.V. J. Am. Soc. Mass Spectrom. 20, 1342–1348 (20)], a novel trapping/release method for restoring the duty cycle of a V-geometry orthoTOFMS to near 100% (referred to as “Zeno pulsing”) was presented. Here, we apply that method to a W-TOF geometry analyzer with analog detection. Across a m/z range of 100–2000, sensitivity gains of ~5–20 are observed, for total ion currents approaching ~10{sup 7} ions·s{sup −1}. Zeno pulsing, or similar strategies for restoring duty cycle, will continue to be important as instrument resolution in orthoTOFMS is increased through the use of ion mirrors. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Electrospray Ionization with High-Resolution Mass Spectrometry as a Tool for Lignomics: Lignin Mass Spectrum Deconvolution

The capability to characterize lignin, lignocellulose, and their degradation products is essential for the development of new renewable feedstocks. Electrospray ionization high-resolution time-of-flight mass spectrometry (ESI-HR TOF-MS) method was developed expanding the lignomics toolkit while targeting the simultaneous detection of low and high molecular weight (MW) lignin species. The effect of a broad range of electrolytes and various ionization conditions on ion formation and ionization effectiveness was studied using a suite of mono-, di-, and triarene lignin model compounds as well as kraft alkali lignin. Contrary to the previous studies, the positive ionization mode was found to be more effective for methoxy-substituted arenes and polyphenols, i.e., species of a broadly varied MW structurally similar to the native lignin. For the first time, we report an effective formation of multiply charged species of lignin with the subsequent mass spectrum deconvolution in the presence of 100 mmol L{sup −1} formic acid in the positive ESI mode. The developed method enabled the detection of lignin species with an MW between 150 and 9000 Da or higher, depending on the mass analyzer. The obtained M{sub n} and M{sub w} values of 1500 and 2500 Da, respectively, were in good agreement with those determined by gel permeation chromatography. Furthermore, the deconvoluted ESI mass spectrum was similar to that obtained with matrix-assisted laser desorption/ionization (MALDI)-HR TOF-MS, yet featuring a higher signal-to-noise ratio. The formation of multiply charged species was confirmed with ion mobility ESI-HR Q-TOF-MS. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Improved Quantitative Dynamic Range of Time-of-Flight Mass Spectrometry by Simultaneously Waveform-Averaging and Ion-Counting Data Acquisition

Two different types of data acquisition methods, “averaging mode” and “ion-counting mode”, have been used in a time-of-flight (TOF) mass spectrometry. The most common method is an averaging mode that sums waveform signals obtained from each flight cycle. While it is possible to process many ions arriving at the same TOF in one flight cycle, low-abundance ions are difficult to measure because ion signals are overwhelmed by noises from the detection system. An ion-counting mode is suitable for the detection of such low-concentration ions, but counting loss occurs when two or more ions arrive at the detector within the dead time of the acquisition system. In this study, we introduce a technique that combines two methods to measure target ions with a high concentration difference, i.e., averaging mode and ion-counting mode are used simultaneously for high abundant and trace ions, respectively. By processing waveforms concurrently during data acquisition, one can choose to analyze either or both types of data to achieve a highly quantitative mass spectrum over a wide range of sample concentrations. The result of the argon isotope analysis shows that this method provides a more accurate determination of the isotope ratio compared to averaging mode alone at one-twentieth of the analysis time required by ion-counting alone. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Tannic Acid: a Novel Calibrator for Facile and Accurate Mass Measurement of Electrospray Ionization Mass Spectrometry

Accurate mass calibration is beneficial to the identification of the unknown compounds quickly and accurately. The ESI mass spectrum of tannic acid (TA) tends to a normal distribution of the cluster ion peaks in m/z range from 371.0368 to 1739.1169. Based on the interesting result, we reported the use of TA, a natural plant polyphenol, as a novel calibrator for electrospray ionization mass spectrometry (ESI MS), which has the following three advantages, including (1) easy preparation, (2) the calibration range of m/z 200~2000, and (3) the calibration error is around 3.00 ppm in positive ion mode, which is less than the use of sodium formate (SF) and Prod #88323 calibrators. This TA calibrator has great potential for the wide applications in biological, chemical, and pharmacal analysis. .

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Zirconium chloride molecular species: combining electron impact mass spectrometry and first principles calculations

Zirconium tetrachloride was synthesized from the reaction between zirconium metal and chlorine gas at 300 °C and was analyzed by electron impact mass spectrometry (EI-MS). Substantial fragmentation products of ZrCl 4 were observed in the mass spectra, with ZrCl 3 being the most abundant species, followed by ZrCl 2 , ZrCl, and Zr. The predicted geometry and kinetic stability of the fragments previously mentioned were investigated by density functional theory (DFT) calculations. Here, energetics of the dissociation processes support the most stable fragment to be ZrCl 3 while the least abundant are ZrCl and ZrCl 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Application of Atmospheric Gases and Particulate Matter to the Assessment of Urban Heat Island

Background: Urban heat island (UHI), where built areas are warmer compared to non-urban regions, increases human related diseases and mortality. A key challenge in UHI analysis is the designation of sites as urban or suburban/rural; however, the growing complexity of green spaces in urban areas and the predominance of the transportation sector in nonurban areas creates a dilemma for distinct delineation. Objectives: This study aims to utilize the variability of atmospheric components such as particulate matter (PM), inorganic gases, and volatile organic compounds (VOCs) as direct tracers of the degree of urbanization for ground-based measurements to fully comprehend UHI in convoluted regions with indistinct delineation of urban and nonurban environments. Methods: Atmospheric gases and aerosols were used as direct tracers of urbanization for UHI analysis. Inorganic gases and particulate matter were monitored in two sites in a southeastern US city with varying degrees of urbanization. VOCs were analyzed using a proton transfer reaction time-of-flight mass spectrometer. Results: The more-urbanized site exhibited warmer night conditions and elevated total oxidant levels, leading to the formation of nanometer-sized particles. Machine learning analysis revealed similar atmospheric pollutant profiles for both sites, suggesting comparable sources and variability. Biogenic VOCs were enhanced at the less-urbanized site; however, levels of anthropogenic aromatic VOCs were comparable for both sites. A comprehensive mass spectra analysis revealed distinct molecular backbones per site that further affirmed the applicability of VOCs as indicators of urbanization. Conclusion: This study concludes that VOCs provide more direct and accurate information than typical inorganic gases and PM parameters for characterizing the degree of urbanization. Further exploration of VOCs can enhance our understanding of UHI dynamics and its interaction with vegetation in urban green spaces.

Air quality sensor↗
DOE OSTI2018

LncRNA MALAT1 regulates oxLDL-induced CD36 expression via activating β-catenin

Highlights: • The role of MALAT1 in lipid uptake was explored. • The regulatory mechanism of oxLDL-induced CD36 was also involved. • We first found oxLDL induces MALAT1 transcription by activating the NF-κB pathway. • MALAT1 promotes lipid uptake by promoting CD36 expression via activating β-catenin. The expression of scavenger receptors in macrophages regulating lipid uptake plays an important role in foam cell formation and the subsequent atherosclerotic plaque formation. Long non-coding RNA MALAT1 is abundantly expressed in THP-1-derived macrophages, and oxidized low-density lipoprotein promotes its transcription by qRT-PCR and RNA FISH detection. Through chemical inhibitor treatments and by performing a dual luciferase reporter analysis, we found that oxLDL induces MALAT1 transcription through the NF-κB pathway. The knockdown of MALAT1 using siRNA transfection affects lipid uptake in macrophages. To understand the details, we checked the scavenger receptors, which mainly control lipid uptake, and found that MALAT1 knockdown decreased CD36 expression. Additionally, we also incubated macrophages with actinomycin D, combined with a dual luciferase reporter analysis, and we found that MALAT1 influenced CD36 expression at the transcription level. We aim to investigate the detailed mechanism by which MALAT1 promotes CD36 transcription, and thus, we designed and synthesized biotin-TEG labeled oligonucleotides to precipitate the MALAT1 RNA-DNA-protein complex in vivo. Combined with SDS-PAGE electrophoresis and a subsequent mass spectra analysis, β-catenin, a transcription factor that promotes CD36 transcription, was found in the complex. By performing R-IPs, we validated that β-catenin was bound to MALAT1 under the oxLDL treatment. In addition, using VAX939, a chemical inhibitor of β-catenin, MALAT1 was demonstrated to promote CD36 transcription partly via β-catenin. We also performed chips to detect whether MALAT1 affects β-catenin accumulation in the binding sites of the CD36 promoter and found that MALAT1 knockdown decreases β-catenin binding to the CD36 promoter and vice versa. In conclusion, oxLDL induced MALAT1 transcription and MALAT1 recruits β-catenin to binding sites on the CD36 promoter to induce CD36 expression, which enhances lipid uptake in macrophages.

60 APPLIED LIFE SCIENCES↗