SciCombinator

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Concept: Absolute

161

Inertial measurement of motion with Attitude and Heading Reference Systems (AHRS) is emerging as an alternative to 3D motion capture systems in biomechanics. The objectives of this study are: 1) to describe the absolute and relative accuracy of multiple units of commercially available AHRS under various types of motion; and 2) to evaluate the effect of motion velocity on the accuracy of these measurements.

Concepts: Medical statistics, Absolute, Measurement, Psychometrics, Units of measurement, Motion capture, Special relativity, God

28

‘Dibal'lin’ on a budget: The enantioselective total syntheses of transtaganolides A-D are rapidly achieved by a highly diastereoselective Ireland-Claisen/Diels-Alder cascade reaction of an enantioenriched geraniol derivative. Based on X-ray diffraction data, the absolute configuration of these metabolites is established and discussed within the context of existing biosynthetic hypotheses.

Concepts: Diffraction, X-ray, Absolute, Stereochemistry, X-ray crystallography, Cascade reaction

28

The diastereoselective synthesis of the C17-C30 fragment of amphidinol 3 (AM3) 1 was achieved from the enantio-enriched aldehyde 20, Weinreb amide 14 and 2-bromo-3-(trimethylsilyl)propene, which was used as a bifunctional conjunctive reagent. The absolute configuration of the stereogenic centers, in both aldehyde 20 and Weinreb amide 14, were efficiently controlled by using (+)-®-methyl-p-tolylsulfoxide as the unique source of chirality.

Concepts: Absolute, Stereochemistry, Functional groups, Weinreb ketone synthesis

28

Racemates of the diphenolic metabolites (±)-tylopilusin A (1) and (±)-tylopilusin B (2) were isolated from the fruiting bodies of Tylopilus eximius. Their structures were elucidated on the basis of spectroscopic analyses (1D and 2D NMR data and ROESY correlations) and X-ray crystallography. Each racemate was separated into its individual enantiomers, and electronic circular dichroism calculations were used to assign the absolute configuration of (+)- and (-)-tylopilusin A (1) and (+)- and (-)-tylopilusin B (2).

Concepts: DNA, X-ray, Crystallography, Absolute, Stereochemistry, Enantiomer, X-ray crystallography, Racemic mixture

27

Limits to athletic performance have long been a topic of myth and debate. However, sport performance appears to have reached a state of stagnation in recent years, suggesting that the physical capabilities of humans and other athletic species, such as greyhounds and thoroughbreds, cannot progress indefinitely. Although the ultimate capabilities may be predictable, the exact path for the absolute maximal performance values remains difficult to assess and relies on technical innovations, sport regulation, and other parameters that depend on current societal and economic conditions. The aim of this literature review was to assess the possible plateau of top physical capabilities in various events and detail the historical backgrounds and sociocultural, anthropometrical, and physiological factors influencing the progress and regression of athletic performance. Time series of performances in Olympic disciplines, such as track and field and swimming events, from 1896 to 2012 reveal a major decrease in performance development. Such a saturation effect is simultaneous in greyhound, thoroughbred, and frog performances. The genetic condition, exhaustion of phenotypic pools, economic context, and the depletion of optimal morphological traits contribute to the observed limitation of physical capabilities. Present conditions prevailing, we approach absolute physical limits and endure a continued period of world record scarcity. Optional scenarios for further improvements will mostly depend on sport technology and modification competition rules.

Concepts: Gene, Absolute, Performance, Performing arts, Thoroughbred, Greyhound

27

The halo-assisted intramolecular addition of silyl enol ethers with in situ activated lactams yielded (hydroxylated) 1-halo-8-azabicyclo[3,2,1]octane and 1-halo-9-azabicyclo[3,3,1]nonane ring systems, which provided an easy enantioselective access to 6β-silyloxytropane-3-one, 3α,6β-dihydroxytropane, and pervilleine B. The absolute configuration of the natural (-)-pervilleine B was determined to be 1R,3R,5S,6R.

Concepts: Absolute, Functional groups, In situ, Integer, Multiplication, Lactam, Lactams

27

From the fruits of the tropical tree Aphanamixis grandifolia, five new evodulone-type limonoids, aphanalides I-M (1-5), one new apo-tirucallane-type triterpenoid, polystanin E (6), and three new chain-like diterpenoids, nemoralisins A-C (7-9), along with 12 known compounds were identified. The absolute configurations were determined by a combination of single-crystal X-ray diffraction studies, Mo2(OAc)4-induced electronic circular dichroism (ECD) data, the Mosher ester method, and calculated ECD data. The cytotoxicities of all the isolates and the insecticidal activities of the limonoids were evaluated.

Concepts: DNA, Diffraction, X-ray, Absolute, Terpenoid, Circular dichroism

27

OBJECTIVE: Clinical assessment of the SPA(PLUS)® system for the determination of the serum free light chains Kappa (κ FLC) and Lambda (λ FLC) compared to the BNII®. DESIGN AND METHODS: 126 serum specimen from our routine activity were analysed on two different analysers: the BNII® (immunonephelometry, Siemens) and the SPA(PLUS) ® (turbidimetry, Binding Site). We compared the absolute values of the serum κ FLC and λ FLC, as well as the FLC κ/λ ratio on both analysers. These results were further evaluated together with the clinical history of the patients. RESULTS: Regression analysis between the BNII® and the SPA(PLUS)® for κ FLC and λ FLC did not display any significant differences between both methods in the normal and pathological ranges. Nevertheless, some differences have been observed for some patients in the absolute value of the involved light chain, with potential clinical implications. CONCLUSION: The results show overall good concordance between both methods. However, it is recommended that the monitoring of patients affected by monoclonal gammapathies by measuring FLC, be performed in the same laboratory and by the same method. Moreover, the FLC results should always be interpreted together with other laboratory tests taking into account the patient’s diagnosis.

Concepts: Statistics, Patient, Hospital, Absolute, Value, Derivative, Immunoglobulin light chain, Absolute value

25

Two new hydroxycitric acid lactone derivatives named cinatrins D (1) and E (2), and a new γ-lactam, virgaricin B (3), along with a known similar compound, virgaricin (4), were isolated from a fermentation broth of the fungus Virgaria boninensis FKI-4958. The absolute stereo structures of the new compounds were established by a combination of spectroscopic methods and chemical modifications. All three newly discovered compounds possessed weak antibacterial activity.The Journal of Antibiotics advance online publication, 22 April 2015; doi:10.1038/ja.2015.45.

Concepts: Spectroscopy, Alcohol, Bacteria, Absolute, Ethanol, Chemical compound, New York City, Near infrared spectroscopy

8

Haematopoietic stem cells (HSCs) arise in the developing aorta during embryogenesis. The number of HSC clones born has been estimated through transplantation, but experimental approaches to assess the absolute number of forming HSCs in a native setting have remained challenging. Here, we applied single-cell and clonal analysis of HSCs in zebrafish to quantify developing HSCs. Targeting creER(T2) in developing cd41:eGFP(+) HSCs enabled long-term assessment of their blood contribution. We also applied the Brainbow-based multicolour Zebrabow system with drl:creER(T2) that is active in early haematopoiesis to induce heritable colour barcoding unique to each HSC and its progeny. Our findings reveal that approximately 21 HSC clones exist prior to HSC emergence and 30 clones are present during peak production from aortic endothelium. Our methods further reveal that stress haematopoiesis, including sublethal irradiation and transplantation, reduces clonal diversity. Our findings provide quantitative insights into the early clonal events that regulate haematopoietic development.

Concepts: Absolute, Heart, Fish, Assessment, Hematology, Aorta, Peak oil, Haematopoiesis