Mass Difference Research Articles

Complementary collider and astrophysical probes of multi-component Dark Matter

We study a new physics scenario with two inert and one active scalar doublets, hence a 3-Higgs Doublet Model (3HDM). We impose a {Z}_2times {Z}_2^{prime } symmetry onto such a 3HDM with one inert doublet odd under the Z2 transformation and the other odd under the {Z}_2^{prime } one. Such a construction leads to a two-component Dark Matter (DM) model. It has been shown that, when there is a sufficient mass difference between the two DM candidates, it is possible to probe the light DM candidate in the nuclear recoil energy in direct detection experiments and the heavy DM component in the photon flux in indirect detection experiments. With the DM masses at the electroweak scale, we show that, independently of astrophysical probes, this model feature can be tested at the Large Hadron Collider via scalar cascade decays in final states. We study several observable distributions whose shapes hint at the presence of the two different DM candidates.

Comparing 13C methyl and deuterated methyl isotopic labeling for the quantification of methyl cellulose patterns using mass spectrometry

The methyl substitution along and among the polymer chains of methyl cellulose (MC) is commonly analyzed by ESI-MS after perdeuteromethylation of the free-OH groups and partial hydrolysis to cello-oligosaccharides (COS). This method requires a correct quantification of the molar ratios of the constituents belonging to a particular degree of polymerization (DP). However, isotopic effects are most pronounced for H/D since their mass difference is 100%. Therefore, we investigated whether more precise and accurate results could be obtained for the methyl distribution of MC by MS of 13CH3 instead of CD3-etherified O-Me-COS. Internal isotope labeling with 13CH3 makes the COS of each DP chemically and physically much more similar, reducing mass fractionation effects, but at the same time requires more complex isotopic correction for evaluation. Results from syringe pump infusion ESI-TOF-MS with 13CH3 and CD3 as isotope label were equal. However, in the case of LC-MS with a gradient system, 13CH3 was superior to CD3. In the case of CD3, the occurrence of a partial separation of the isotopologs of a particular DP resulted in slight distortion of the methyl distribution since the signal response is significantly dependent on the solvent composition. Isocratic LC levels this problem, but one particular eluent-composition is not sufficient for a series of oligosaccharides with increasing DP due to peak broadening. In summary, 13CH3 is more robust to determine the methyl distribution of MCs. Both syringe pump and gradient-LC-MS measurements are possible, and the more complex isotope correction is not a disadvantage.Graphical abstract

Measurement of the mass and width of the Λc(2625)+ charmed baryon and the branching ratios of Λc(2625)+→Σc0π+ and Λc(2625)+→Σc++π−

Using the entire data sample of 980 fb−1 collected at or near the ϒ(4S) resonance with the Belle detector operating at the KEKB asymmetric-energy e+e− collider, we report the measurement of the mass, width, and the branching ratios of the Λc(2625)+ charmed baryon. The mass difference between Λc(2625)+ and Λc+ is measured to be M(Λc(2625)+)−M(Λc+)=341.518±0.006±0.049 MeV/c2. The upper limit on the width is measured to be Γ(Λc(2625)+)<0.52 MeV/c2 at 90% confidence level. Based on a full Dalitz plot fit, branching ratios with respect to the mode Λc(2625)+→Λc+π+π− are measured to be B(Λc(2625)+→Σc0π+)B(Λc(2625)+→Λc+π+π−)=(5.19±0.23±0.40)% and B(Λc(2625)+→Σc++π−)B(Λc(2625)+→Λc+π+π−)=(5.13±0.26±0.32)%, where the first and second uncertainties are statistical and systematic, respectively. These measurements can be used to further constrain the parameters of the underlying theoretical models.Received 13 December 2022Accepted 20 January 2023DOI:https://doi.org/10.1103/PhysRevD.107.032008Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsCharmed baryonsPropertiesParticle propertiesTechniquesParticle decaysParticles & Fields

Carpal allometry of African apes among mammals.

Morphological variation in African ape carpals has been used to support the idea that Pan and Gorilla evolved knuckle-walking independently. Little work, however, has focused on the effect of body mass on carpal morphology. Here, we compare carpal allometry in Pan and Gorilla to that of other quadrupedal mammals with similar body mass differences. If allometric trends in Pan and Gorilla carpals mirror those of other mammals with similar body mass variation, then body mass differences may provide a more parsimonious explanation for African ape carpal variation than the independent evolution of knuckle-walking. Three linear measurements were collected on the capitate, hamate, lunate, and scaphoid (or scapholunate) of 39 quadrupedal species from six mammalian families/subfamilies. Relationships between linear measurements and estimated body mass were analyzed using reduced major axis regression. Slopes were compared to 0.33 for isometry. Within Hominidae, higher body mass taxa (Gorilla) have relatively anteroposteriorly wider, mediolaterally wider, and/or proximodistally shorter capitates, hamates, and scaphoids than low body mass taxa (Pan). These allometric relationships are mirrored in most, but not all, mammalian families/subfamilies included in the analysis. Within most mammalian families/subfamilies, carpals of high body mass taxa are proximodistally shorter, anteroposteriorly wider, and mediolaterally wider than those of low body mass taxa. These distinctions may be caused by the need to accommodate relatively higher forelimb loading associated with greater body mass. Because these trends occur within multiple mammalian families/subfamilies, some carpal variation in Pan and Gorilla is consistent with body mass differences.

MetaboDirect: an analytical pipeline for the processing of FT-ICR MS-based metabolomic data

BackgroundMicrobiomes are now recognized as the main drivers of ecosystem function ranging from the oceans and soils to humans and bioreactors. However, a grand challenge in microbiome science is to characterize and quantify the chemical currencies of organic matter (i.e., metabolites) that microbes respond to and alter. Critical to this has been the development of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), which has drastically increased molecular characterization of complex organic matter samples, but challenges users with hundreds of millions of data points where readily available, user-friendly, and customizable software tools are lacking.ResultsHere, we build on years of analytical experience with diverse sample types to develop MetaboDirect, an open-source, command-line-based pipeline for the analysis (e.g., chemodiversity analysis, multivariate statistics), visualization (e.g., Van Krevelen diagrams, elemental and molecular class composition plots), and presentation of direct injection high-resolution FT-ICR MS data sets after molecular formula assignment has been performed. When compared to other available FT-ICR MS software, MetaboDirect is superior in that it requires a single line of code to launch a fully automated framework for the generation and visualization of a wide range of plots, with minimal coding experience required. Among the tools evaluated, MetaboDirect is also uniquely able to automatically generate biochemical transformation networks (ab initio) based on mass differences (mass difference network-based approach) that provide an experimental assessment of metabolite connections within a given sample or a complex metabolic system, thereby providing important information about the nature of the samples and the set of microbial reactions or pathways that gave rise to them. Finally, for more experienced users, MetaboDirect allows users to customize plots, outputs, and analyses.ConclusionApplication of MetaboDirect to FT-ICR MS-based metabolomic data sets from a marine phage-bacterial infection experiment and a Sphagnum leachate microbiome incubation experiment showcase the exploration capabilities of the pipeline that will enable the research community to evaluate and interpret their data in greater depth and in less time. It will further advance our knowledge of how microbial communities influence and are influenced by the chemical makeup of the surrounding system. The source code and User’s guide of MetaboDirect are freely available through (https://github.com/Coayala/MetaboDirect) and (https://metabodirect.readthedocs.io/en/latest/), respectively.4Ei9vvQrsS4QW-6gNudv2GVideo

Bioprocess Development and Characterization of a 13C-Labeled Hybrid Bispecific Antibody Produced in Escherichia coli

Monoclonal antibodies (mAbs) are highly efficacious therapeutics; however, due to their large, dynamic nature, structural perturbations and regional modifications are often difficult to study. Moreover, the homodimeric, symmetrical nature of mAbs makes it difficult to elucidate which heavy chain (HC)-light chain (LC) pairs are responsible for any structural changes, stability concerns, and/or site-specific modifications. Isotopic labeling is an attractive means for selectively incorporating atoms with known mass differences to enable identification/monitoring using techniques such as mass spectrometry (MS) and nuclear magnetic resonance (NMR). However, the isotopic incorporation of atoms into proteins is typically incomplete. Here we present a strategy for incorporating 13C-labeling of half antibodies using an Escherichia coli fermentation system. Unlike previous attempts to generate isotopically labeled mAbs, we provide an industry-relevant, high cell density process that yielded >99% 13C-incorporation using 13C-glucose and 13C-celtone. The isotopic incorporation was performed on a half antibody designed with knob-into-hole technology to enable assembly with its native (naturally abundant) counterpart to generate a hybrid bispecific (BsAb) molecule. This work is intended to provide a framework for producing full-length antibodies, of which half are isotopically labeled, in order to study the individual HC-LC pairs.

Symmetry breaking for semiconductor excitons induced by Coulomb coupling between heavy and light holes

Semiconductor excitons are commonly seen as hydrogen atom. This analogy requires a unique hole mass. In reality, this is not so due to the complexity of the semiconductor band structure. The precise consequences on the exciton physics of the Coulomb coupling between heavy and light holes remain a tricky open problem. Through an ``optimized perturbative'' approach that uses excitons with a flexible hole mass as a basis, we show that for zero exciton wave vector, the heavy-light hole mass difference does not split the $(2\times4)$ exciton degeneracy in zinc-blende-like semiconductors, the hole mass for binding energy being close to the average mass inverse. By contrast, for nonzero exciton wave vector, that physically breaks the crystal symmetry, the exciton degeneracy splits into two branches quantized along the exciton wave vector, with nontrivial center-of-mass dependence not only on the heavy and light hole masses, but also on the electron mass.

Development of an equine muscle condition score

SummaryBackgroundMuscle mass influences performance and health in horses. It is important to be able to easily evaluate muscle mass in horses.ObjectivesTo develop an equine muscle condition score (MCS) to be used by veterinarians, horse owners, trainers and other people involved in horse management and training.Study designObservational, cross‐sectional study.MethodsTwenty‐five Thoroughbred horses at different training levels were included. Initial assessment included body condition score, height and bodyweight. Seven muscles (m. splenius, m. brachiocephalicus, m. multifidus, m. longissimus dorsi, m. gluteus medius, m. semitendinosus and m. tensor fascia latae) were imaged using ultrasonography and measured. Repeatability of ultrasonographic measurements was tested in advance by measuring each muscle 10 times in two horses. Muscle sizes were compared between two groups; trained and untrained to determine difference in muscle mass. Horses were subsequently ranked according to measured muscle mass, and palpable and visual differences between horses at different ranks were identified. A 5‐point MCS was developed. The MCS was tested by an independent, blinded operator in all 25 horses.ResultsUltrasonographic measurement of all muscles had a coefficient of variation under 5%. All muscle sizes were significantly correlated to each other except for m. brachiocephalicus, which was not correlated to m. semitendinosus and m. multifidus. All muscles were significantly larger in trained horses than in untrained horses except for m. brachiocephalicus and m. splenius. After testing, minor adjustments were made to optimise usability of the score.Main limitationsThe study population consisted of very similar horses. Further studies are needed to test the reliability of the MCS in horses of different breeds, disciplines, body condition scores and health.ConclusionThis study resulted in an equine MCS that could identify differences in muscle mass between horses. The resulting MCS was similar to other muscle assessment systems developed independently from our study, thus strengthening the findings.

Differences in mating system and predicted parental conflict affect post-pollination reproductive isolation in a flowering plant.

Mating system shifts from outcrossing to selfing are frequent in plant evolution. Relative to outcrossing, selfing is associated with reduced parental conflict over seed provisioning, which may result in postzygotic, asymmetric, reproductive isolation in crosses between populations of different mating systems. To test the hypothesis that post-pollination reproductive isolation between populations increases with increasing differences in mating system and predicted parental conflict, we performed a crossing experiment involving all combinations of three self-compatible populations (with low outcrossing rates), and three self-incompatible populations (with high outcrossing rates) of the arctic-alpine herb Arabis alpina, assessing fitness-related seed and plant traits of the progeny. Predicted levels of parental conflict ("genome strength") were quantified based on strength of self-incompatibility and estimates of outcrossing rates. Crosses between self-compatible and self-incompatible populations yielded very small seeds of low viability, resulting in strong reproductive isolation. In 14 of 15 reciprocal between-population crosses, seeds were heavier when the paternal plant had the stronger genome, and seed mass differences between cross directions increased with an increased difference in parental conflict. Overall, our results suggest that, when sufficiently large, differences in mating system and hence in expected parental conflict may result in strong post-pollination reproductive barriers contributing to speciation.

Reproductive and Morphological Characteristics of Hemidactylus turcicus (Squamata: Gekkonidae) and Tarentola annularis (Squamata: Phyllodactylidae) in Southern Egypt

Hemidactylus turcicus and Tarentola annularis are occasionally sympatric and are ecologically similar in vertical wall microhabitat. For this reason, I studied their sexual, fat-body, and liver cycles for three years. All morphological variables are male-biased in T. annularis, unlike male H. turcicus, which showed significant differences in head sizes only. Females exhibited a spring to summer vitellogenic period with ovulation occurring during mid-spring to mid-summer in T. annularis and from late spring to late summer in H. turcicus. The mean clutch size of oviductal eggs (1.86) and relative clutch mass (0.188) was higher in H. turcicus than in T. annularis (1.67 and 0.132). Relative clutch mass was negatively correlated with snout–vent length in T. annularis but was not in H. turcicus. Sperm were present in the epididymis for eight months in H. turcicus while year-round in T. annularis. Post-breeding, masses of liver and fat body increased in both sexes of both species. There were significant differences in fat body and liver masses between the sexes of both species. Based on the liver-mass cycle, the energy expenditure on reproduction in male and female T. annularis was high compared with the corresponding sexes of H. turcicus. Testicular recrudescence began in late fall or early winter corresponding to lower temperatures, photoperiod, and precipitation. Testicular regression occurred at the highest temperatures in late summer and early fall.

Molecular transformation of dissolved organic matter in refinery wastewaters: Characterized by FT-ICR MS coupled with electrospray ionization and atmospheric pressure photoionization

Dissolved organic matter (DOM) in refinery wastewater is an extremely complex mixture of various organic compounds. Using mass spectrometry, it is impossible to characterize all of the DOM molecules with only one ionization source. In this study, negative-ion, electrospray ionization (ESI), positive-ion ESI, and positive-ion atmospheric pressure photoionization (APPI) were coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to analyze the molecular composition of DOM in a refinery wastewater stream during the treatment process. There were obvious differences in the heteroatom composition, number of DOM constituents, and chemical properties in refinery wastewater under the three ionization modes. Acidic CHO and CHOS compounds detected by (−)ESI, basic CHN and CHON compounds detected by (+)ESI, and hydrocarbons detected by (+)APPI were analyzed to determine the molecular transformations that occurred during treatment. In an anaerobic biological treatment process, acidic CHO and CHOS compounds with a high oxygen content were preferentially removed, and acidic CHO and CHOS compounds with a low oxygen content were produced. In an aerobic biological process, acidic CHO and CHOS compounds with a low oxygen content were preferentially removed, and acidic CHO and CHOS compounds with a high oxygen content were produced. The whole biological treatment process has a poor removal efficiency for CHN and CHON compounds, and hydrocarbons. An activated carbon (AC) adsorption process removed different heteroatom compounds mainly with a low oxygen content for acidic and basic compounds. The transformation mechanism of CHO and CHOS compounds in the biological treatment process was analyzed by the Kendrick mass defect (KMD) theory and a mass difference network analysis. In the anaerobic process, large amounts of oxygenated CHO and CHOS compounds were degraded by decarboxylation, deoxydation, demethoxylation, and dehydration reactions, and converted to lower oxygen content compounds. In the aerobic processes, these low oxygen CHO and CHOS compounds mainly underwent carboxylation and oxidation reactions. This study determined the transformation characteristics and mechanisms of different types of organic compounds in refinery wastewater during the treatment process. The results provide guidance for the design and optimization of technologies for refinery wastewater treatment. • Molecular composition of DOM in refinery wastewater was characterized by ESI and APPI FT-ICR MS. • Transformation characteristics and mechanism of different types of compound were investigated. • Biological process could remove acidic CHO and CHOS compounds. • AC adsorption process removed various different heteroatom compounds.

Mechanistic Study into Free Radical-Activated Glycan Dissociations through Isotope-Labeled Cellobioses.

Inspired by the electron-activated dissociation technique, the most potent tool for glycan characterization, we recently developed free radical reagents for glycan structural elucidation. However, the underlying mechanisms of free radical-induced glycan dissociation remain unclear and, therefore, hinder the rational optimization of the free radical reagents and the interpretation of tandem mass spectra, especially the accurate assignment of the relatively low-abundant but information-rich ions. In this work, we selectively incorporate the 13C and/or 18O isotopes into cellobiose to study the mechanisms for free radical-induced dissociation of glycans. The eight isotope-labeled cellobioses include 1-13C, 3-13C, 1'-13C, 2'-13C, 3'-13C, 4'-13C, 5'-13C, and 1'-13C-4-18O-cellobioses. Upon one-step collisional activation, cross-ring (X ions), glycosidic bond (Y-, Z-, and B-related ions), and combinational (Y1 + 0,4X0 ion) cleavages are generated. These fragment ions can be unambiguously assigned and confirmed by the mass difference of isotope labeling. Importantly, the relatively low-abundant but information-rich ions, such as 1,5X0 + H, 1,4X0 + H, 2,4X0 + H-OH, Y1 + 0,4X0, 2,5X1-H, 3,5X0-H, 0,3X0-H, 1,4X0-H, and B2-3H, are confidently assigned. The mechanisms for the formations of these ions are investigated and supported by quantum chemical calculations. These ions are generally initiated by hydrogen abstraction followed by sequential β-elimination and/or radical migration. Here, the mechanistic study for free radical-induced glycan dissociation allows us to interpret all of the free radical-induced fragment ions accurately and, therefore, enables the differentiation of stereochemical isomers. Moreover, it provides fundamental knowledge for the subsequent development of bioinformatics tools to interpret the complex free radical-induced glycan spectra.

Electrical property enhancement and lattice thermal conductivity reduction of n-type Mg3Sb1.5Bi0.5-based Zintl compound by In&Se co-doping

Mg3Sb1.5Bi0.5-based Zintl compounds have attracted extensive attention as potential thermoelectric materials due to their earth-abundant elements. However, pure and intrinsic Mg3Sb1.5Bi0.5 manifests a poor thermoelectric performance because of its low electrical conductivity of about 3 × 102 S/m at room temperature. In this work, In and Se co-doping was carried out to optimize the thermoelectric performance of n-type Mg3Sb1.5Bi0.5-based material. The experimental results revealed that the carrier concentration and mobility of Mg3Sb1.5Bi0.5 significantly increased after In and Se co-doping, leading to an improvement of power factor. Simultaneously, lattice thermal conductivity was significantly reduced due to the large mass difference between In and Mg. A maximum zT of 1.64 at 723 K was obtained for the Mg3.17In0.03Sb1.5Bi0.49Se0.01 sample. And an average zT value of about 1.1 between 300 and 723 K was achieved, which insures its possible application at medium temperature range as a non-toxic and low-cost TE material.

High-Throughput Quantitative Glycomics Enabled by 12-plex Isobaric Multiplex Labeling Reagents for Carbonyl-Containing Compound (SUGAR) Tags.

Glycans, which are widely distributed on most proteins and cell surfaces, are a class of important biomolecules playing crucial roles in various biological processes such as immune response and cellular communication. Modern mass spectrometry (MS) coupled with novel chemical probes greatly facilitates routine analysis of glycans. However, the requirement of high-throughput analysis still calls for advanced tools to be developed. Recently, we devised isobaric multiplex reagents for carbonyl-containing compound (SUGAR) tags for 4-plex N-glycan analysis. To further improve the throughput, we utilized the subtle mass differences among different isotopologues and expanded the multiplexing capacity to 12 channels, a 3-fold throughput improvement for the original SUGAR tag design and achieved high-throughput N-glycan analysis in a single LC-MS/MS injection. We then applied 12-plex SUGAR tags to profile the N-glycans in four subtypes of human Immunoglobulin G (IgG) and to investigate the N-glycan changes in the endometrial cancer cells (ECC1) treated with Atovaquone, a quinone antimicrobial medication, and a dihydroorotate dehydrogenase (DHODH) inhibitor. Data are available via ProteomeXchange with the identifier PXD038501.

Interface design of transparent thermoelectric epitaxial ZnO/SnO2 multilayer film for simultaneous realization of low thermal conductivity and high optical transmittance

A transparent thermoelectric material requires not only high thermoelectric performance but also high optical transmittance. However, in transparent nanostructured thermoelectric materials, the nanostructure interface brings the trade-off relationship between thermal conductivity and optical transmittance. We propose an approach for the simultaneous control of thermal conductivity and optical transmittance in the epitaxial nanostructured films, where carriers can be smoothly transported. This is realized by the interface design based on the three strategies: (1) a large atomic mass difference at the heterointerface for low thermal conductivity; (2) heterointerface with almost the same refractive index and flat surface for high optical transmittance; and (3) epitaxial heterointerface for smooth carrier transport. We formed epitaxial ZnO/SnO2 multilayer films based on this design guideline. The multilayer films exhibit lower thermal conductivity and higher optical transmittance than an ever reported transparent nanostructured thermoelectric material. These results highlight that this design is promising to realize high-performance transparent nanostructured thermoelectric materials.

High-Sensitivity Wireless Sensing Using Amorphous Magnetic Microwires

Glass-coated amorphous ferromagnetic microwires subjected to variations in mass loading and parallel wire arrays with 0.5–6-cm interwire spacing were found to deliver exceptional magnetomechanical and wireless giant magnetoimpedance (GMI) responses, in the kilohertz and microwave range, respectively. The microwires allow wireless quantification of microgram mass differences: the magnetomechanical resonance frequency measured in zero applied field demonstrates an approximately linear decrease of 3 Hz/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g}$ </tex-math></inline-formula> , and a sensitivity response that is ten times greater than that reported for commercial METGLAS-type amorphous magnetic ribbons of comparable length. Microwave giant magnetoimpedance data collected from planar arrays of parallel microwires show either constructive or destructive interference when compared to data obtained from a single microwire. The exceptional responsiveness of the glass-coated amorphous ferromagnetic microwires to mass loading and to geometric arrangement, along with their small diameter and ease of fabrication, highlights their promise for a wide variety of sensor applications, including biosensing, civil infrastructure monitoring, and high-throughput remote detection schemes.

Post-Neutron Mass Yield Distribution in the Thermal Neutron Induced Fission of 233U

In the thermal neutron–induced fission of 233U, the cumulative and independent yields of various fission products within the mass ranges of 77 to 109 and 123 to 155 have been measured by using an off-line gamma-ray spectrometric technique. The lower yields of 86Br and 136I than usual trend indicate the formation of delayed neutron emitters 87Br and 137I. From the cumulative yields, the post-neutron mass yield distribution was obtained after applying the charge distribution correction. The data from the present and earlier work of our laboratory in the 233U(nth,f) reaction were compared with similar data of 232,235U(nth,f) and 238U(n,f) reactions to examine the effect of mass difference of the fissioning systems on the fine structure of the mass yield distribution. The mass yield distribution in the 233U(nth,f) reaction was also compared with those of 229Th(nth,f), 241Pu(nth,f), and 245Cm(nth,f) reactions to examine the effect of charge and mass difference of the fissioning systems and also to examine the different behaviors of standard I and standard II asymmetric modes of fission.

Investigation of dry-wet cycles effect on the durability of modified rubberised concrete

For communities and property in flood-prone locations, the performance of construction materials during flood occurrences is important. Limited investigations are available on the influence of dry-wet water cycles on rubberised concrete after rubber crumbs treatment. Several tests are done to assess rubberised concrete's mechanical and durability characteristics and compare it to conventional concrete. An optimum amount (15%) of rubber crumbs are utilised for partially replacing fine aggregate in concrete. Physical appearance, surface cracks, compressive strength, mass difference and ultrasonic pulse velocity of RuC have been tested under water dry-wet cycles. After dry-wet cycles, RuC gains its compressive strength, mass and ultrasonic pulse velocity. No harmful effect is found under dry-wet cycles of water. After rubber crumbs treatment and using pozzolana-based cement, the rubberised concrete can struggle with dry-wet water cycles during flood conditions for a long duration.

Precise estimate of charged Wino decay rate

The Wino is an SU(2)L triplet Majorana fermion and a well-motivated dark matter candidate. The mass difference between the charged and the neutral Winos is small thanks to the SU(2)L symmetry. The small mass difference makes the charged Wino metastable, which provides disappearing charged track signatures at collider experiments. The constraint on the Wino dark matter at the LHC strongly depends on the Wino lifetime. We compute the next-to-leading order (NLO) correction of the charged Wino decay and make the most precise estimate of the decay rate. We find that the NLO decay rate is determined by the mass difference and scarcely depend on the Wino mass itself in the heavy Wino limit. As a result, we find the NLO correction gives a minor impact on the lifetime of 2–4% increase.

Systematic analysis of in-source modifications of primary metabolites during flow-injection time-of-flight mass spectrometry

Flow-injection mass spectrometry (FI-MS) enables metabolomics studies with a very high sample-throughput. However, FI-MS is prone to in-source modifications of analytes because samples are directly injected into the electrospray ionization source of a mass spectrometer without prior chromatographic separation. Here, we spiked authentic standards of 160 primary metabolites individually into an Escherichia coli metabolite extract and measured the thus derived 160 spike-in samples by FI-MS. Our results demonstrate that FI-MS can capture a wide range of chemically diverse analytes within 30 s measurement time. However, the data also revealed extensive in-source modifications. Across all 160 spike-in samples, we identified significant increases of 11,013 ion peaks in positive and negative mode combined. To explain these unknown m/z features, we connected them to the m/z feature of the (de-)protonated metabolite using information about mass differences and MS2 spectra. This resulted in networks that explained on average 49 % of all significant features. The networks showed that a single metabolite undergoes compound specific and often sequential in-source modifications like adductions, chemical reactions, and fragmentations. Our results show that FI-MS generates complex MS1 spectra, which leads to an overestimation of significant features, but neutral losses and MS2 spectra explain many of these features.