scholarly journals Microlensing mass measurement from images of rotating gravitational arcs

2021 ◽  
Author(s):  
Arnaud Cassan ◽  
Clément Ranc ◽  
Olivier Absil ◽  
Łukasz Wyrzykowski ◽  
Krzysztof A. Rybicki ◽  
...  
Keyword(s):  
Mass Measurement

Conformation of eukaryotic ribosomal RNAs

1983 ◽  
Vol 41 ◽  
pp. 592-593
Author(s):  
M. Boublik ◽  
G. Thornton ◽  
G. Oostergetel ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Molecular Weight ◽  
Mass Measurement ◽  
Carbon Film ◽  
Structural Complexity ◽  
Scanning Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Pure Nitrogen ◽  
Freeze Dried ◽  
Scanning Transmission ◽  
Partially Unfolded

Understanding the structural complexity of ribosomes and their role in protein synthesis requires knowledge of the conformation of their components - rRNAs and proteins. Application of dedicated scanning transmission electron microscope (STEM), electrical discharge of the support carbon film in an atmosphere of pure nitrogen, and determination of the molecular weight of individual rRNAs enabled us to obtain high resolution electron microscopic images of unstained freeze-dried rRNA molecules from BHK cells in a form suitable for evaluation of their 3-D structure. Preliminary values for the molecular weight of 28S RNA from the large and 18S RNA from the small ribosomal subunits as obtained by mass measurement were 1.84 x 106 and 0.97 x 106, respectively. Conformation of rRNAs consists, in general, of alternating segments of intramolecular hairpin stems and single stranded loops in a proportion which depends on their ionic environment, the Mg++ concentration in particular. Molecules of 28S RNA (Fig. 1) and 18S RNA (not shown) obtained by freeze-drying from a solution of 60 mM NH+4 acetate and 2 mM Mg++ acetate, pH 7, appear as partially unfolded coils with compact cores suggesting a high degree of ordered secondary structure.

Detection and identification of Catalpol metabolites in the rat plasma, urine and faeces using ultra-high performance liquid chromatography-Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry

2020 ◽  
Vol 21 ◽  
Author(s):  
Zedong Xiang ◽  
Shaoping Wang ◽  
Haoran Li ◽  
Pingping Dong ◽  
Fan Dong ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Performance ◽  
Mass Measurement ◽  
Neutral Loss ◽  
Rat Plasma ◽  
Accurate Mass ◽  
Chromatographic Retention ◽  
Rat Urine ◽  
Q Exactive

Background:: Catalpol, an iridoid glycoside, is one of the richest bioactive components present in Rehmannia glutinosa. More and more metabolites of drugs have exhibit various pharmacological effects, thus providing guidance for clinical application. However, few researches have paid attention on the metabolism of catalpol. Objective:: This study aimed to establish a rapid and effective method to identify catalpol metabolites and evaluate the biotransformation pathways of catalpol in rats. Methods:: In this study, catalpol metabolites in rat urine, plasma and faeces were analyzed by UHPLC-Q-Exactive MS for the characterization of metabolism of catalpol. Based on high-resolution extracted ion chromatograms (HREICs) and parallel reaction monitoring mode (PRM), metabolites of catalpol were identified by comparing the diagnostic product ions (DPIs), chromatographic retention times, neutral loss fragments (NLFs) and accurate mass measurement with those of catalpol reference standard. Results: A total of 29 catalpol metabolites were detected and identified in both negative and positive ion modes. Nine metabolic reactions including deglycosylation, hydroxylation, dihydroxylation, hydrogenation, dehydrogenation, oxidation of methylene to ketone, glucuronidation, glycine conjugation and cysteine conjugation were proposed. Conclusion:: A rapid and effective method based on UHPLC-Q-Exactive MS was developed to mine the metabolism information of catalpol. Results of metabolites and biotransformation pathways of catalpol suggested that when orally administrated, catalpol was firstly metabolized into catalpol aglycone, after which phase Ⅰ and phase Ⅱ reactions occurred. However, hydrophilic chromatography-mass spectrometry still needed to further find the polar metabolites of catalpol.

scholarly journals First Penning trap mass measurement of Ca36

2021 ◽  
Vol 103 (1) ◽  
Author(s):  
J. Surbrook ◽  
G. Bollen ◽  
M. Brodeur ◽  
A. Hamaker ◽  
D. Pérez-Loureiro ◽  
...  
Keyword(s):  
Penning Trap ◽  
Mass Measurement

scholarly journals Physical seed dormancy in Abrus precatorious (Ratti): a scientific validation of indigenous technique

2021 ◽  
Vol 2 ◽  
Author(s):  
Rajender Kumar Sharma
Keyword(s):  
Indigenous People ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Seed Weight ◽  
Mass Measurement ◽  
Storage Period ◽  
Abrus Precatorius ◽  
Moisture Storage ◽  
Moisture Conditions ◽  
Scientific Validation

Abstract Seeds of Abrus precatorius L. (Fabaceae) were used as weight measure by Indigenous people. Where, the seeds were referred as Ratti; a traditional Indian unit of mass measurement. Seed weight fluctuates depending upon age, moisture, storage-period/conditions. Therefore, use of seeds as a weighing unit become dubious and need to be validated. For this purpose, seeds of A. precatorious were subjected to different moisture conditions and periodically monitored. Surprisingly, there was no change in seed weight was observed, indicating the impermeability of seed coat. The later was confirmed by scarification of seed coat which resulted in 53% increase in seed weight against 0% in control. Further, presence of a potent toxin (abrin) in the seed coat protects it from pests and microbes, and contributes to the maintenance of impermeability for longer period of time. The data validates the use of A. precatorious seeds as a weighing unit (ratti) by the indigenous people and discussed.

scholarly journals Optimising top-quark threshold scan at CLIC using genetic algorithm

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
K. Nowak ◽  
A.F. Żarnecki
Keyword(s):  
Genetic Algorithm ◽  
Pair Production ◽  
Top Quark ◽  
Quark Mass ◽  
Mass Measurement ◽  
Production Cross ◽  
Model Parameters ◽  
Top Quark Mass ◽  
Systematic Uncertainties ◽  
Pair Production Cross Section

Abstract One of the important goals at the future e+e− colliders is to measure the top-quark mass and width in a scan of the pair production threshold. However, the shape of the pair-production cross section at the threshold depends also on other model parameters, as the top Yukawa coupling, and the measurement is a subject to many systematic uncertainties. Presented in this work is the study of the top-quark mass determination from the threshold scan at CLIC. The most general approach is used with all relevant model parameters and selected systematic uncertainties included in the fit procedure. Expected constraints from other measurements are also taken into account. It is demonstrated that the top-quark mass can be extracted with precision of the order of 30 to 40 MeV, including considered systematic uncertainties, already for 100 fb−1 of data collected at the threshold. Additional improvement is possible, if the running scenario is optimised. With the optimisation procedure based on the genetic algorithm the statistical uncertainty of the mass measurement can be reduced by about 20%. Influence of the collider luminosity spectra on the expected precision of the measurement is also studied.

Clinical implication of psoas muscle mass measurement for predicting death within 3 months in patients with incurable uterine cervical or corpus malignancy

2021 ◽  
Author(s):  
Hiroyuki Kurosu ◽  
Yukiharu Todo ◽  
Ryutaro Yamada ◽  
Kaoru Minowa ◽  
Tomohiko Tsuruta ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Muscle Mass ◽  
Cancer Cachexia ◽  
Mass Measurement ◽  
Characteristic Curve ◽  
Lumbar Vertebra ◽  
Psoas Muscle ◽  
Data Set ◽  
Cutoff Value ◽  
Computed Tomography Images

Abstract Objective The aim of this study was to find a clinical marker for identifying refractory cancer cachexia. Methods We analyzed computed tomography imaging data, which included the third lumbar vertebra, from 94 patients who died of uterine cervix or corpus malignancy. The time between the date of examination and date of death was the most important attribute for this study, and the computed tomography images were classified into >3 months before death and ≤ 3 months before death. Psoas muscle mass index was defined as the left–right sum of the psoas muscle areas (cm2) at the level of third lumbar vertebra, divided by height squared (m2). Results A data set of 94 computed tomography images was obtained at baseline hospital visit, and a data set of 603 images was obtained at other times. One hundred (16.6%) of the 603 non-baseline images were scanned ≤3 months before death. Mean psoas muscle mass index change rates at >3 months before death and ≤3 months before death were −1.3 and −20.1%, respectively (P < 0.001). Receiver operating characteristic curve analysis yielded a cutoff value of −13.0%. The area under the curve reached a moderate accuracy level (0.777, 95% confidence interval 0.715–0.838). When we used the cutoff value to predict death within 3 months, sensitivity and specificity were 74.0 and 82.1%, respectively. Conclusions Measuring change in psoas muscle mass index might be useful for predicting cancer mortality within 3 months. It could become a potential tool for identifying refractory cancer cachexia.

scholarly journals Nuclear mass measurements with radioactive ion beams

2019 ◽  
Vol 28 (04) ◽  
pp. 1930005 ◽  
Author(s):  
Michael A. Famiano
Keyword(s):  
Mass Measurement ◽  
Measurement Techniques ◽  
Nuclear Mass ◽  
Mass Measurements ◽  
Future Directions ◽  
Advantages And Disadvantages ◽  
Nuclear Masses ◽  
Under Construction ◽  
Very High ◽  
Practical Constraints

Nuclear masses are the most fundamental of all nuclear properties, yet they can provide a wealth of knowledge, including information on astrophysical sites, constraints on existing theory, and fundamental symmetries. In nearly all applications, it is necessary to measure nuclear masses with very high precision. As mass measurements push to more short-lived and more massive nuclei, the practical constraints on mass measurement techniques become more exacting. Various techniques used to measure nuclear masses, including their advantages and disadvantages are described. Descriptions of some of the world facilities at which the nuclear mass measurements are performed are given, and brief summaries of planned facilities are presented. Future directions are mentioned, and conclusions are presented which provide a possible outlook and emphasis on upcoming plans for nuclear mass measurements at existing facilities, those under construction, and those being planned.

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