The affinities of extinct organisms are often difficult to resolve using morphological data alone. Chemical analysis of carbonaceous specimens can complement traditional approaches, but the search ...for taxon-specific signals in ancient, thermally altered organic matter is challenging and controversial, partly because suitable positive controls are lacking. Here, we show that non-destructive Fourier Transform Infrared Spectroscopy (FTIR) resolves in-situ molecular fingerprints in the famous 407 Ma Rhynie chert fossil assemblage of Aberdeenshire, Scotland, an important early terrestrial Lagerstätte. Remarkably, unsupervised clustering methods (principal components analysis and K-mean) separate the fossil spectra naturally into eukaryotes and prokaryotes (cyanobacteria). Additional multivariate statistics and machine-learning approaches also differentiate prokaryotes from eukaryotes, and discriminate eukaryotic tissue types, despite the overwhelming influence of silica. We find that these methods can clarify the affinities of morphologically ambiguous taxa; in the Rhynie chert for example, we show that the problematic "nematophytes" have a plant-like composition. Overall, we demonstrate that the famously exquisite preservation of cells, tissues and organisms in the Rhynie chert accompanies similarly impressive preservation of molecular information. These results provide a compelling positive control that validates the use of infrared spectroscopy to investigate the affinity of organic fossils in chert.
In many systematic groups of mammalian species, the evolution of sociality leads to the formation of large social groups (group-size evolution). In rodents, however, the most social species live in ...family groups consisting, as a rule, of a fairly small number of individuals. The family-group lifestyle of some terrestrial sciurids (Sciuridae) and voles (
Microtus
) results in fewer breeding adult females, a decreased litter size, and a longer time before the first reproduction. Statistical analysis of published data performed in this study showed that the transition to the family-group lifestyle leads to decreased potential reproductive success in many muroid rodents: females produce fewer litters and, consequently, fewer pups during the breeding season. However, the potential reproductive success in muroid rodents with a family-group lifestyle could be increased due to delayed offspring dispersal (who spend the severe winter period in family groups) and extensive cooperation in foraging and in defending their territory and food reserves, as well as in care-giving activities. It can be assumed that females of these species produce fewer offspring, yet of “better quality.” Ultimately, social rodent species may gain inclusive fitness benefits because of the higher fitness of their offspring as compared to solitary dwellers and gregarious species.
This study reviews the structure and properties of nanostructured composite conductometric sensors based on semiconducting metal oxides, and the physico-chemical processes occurring when applied for ...detection of ambient reducing gases. It discusses the mechanisms of electronic and chemical sensitization in composites comprised of metal oxides of different electronic and chemical properties. In particular, the relationship between the conductivity mechanisms and sensory effect is examined, considering the transfer of electrons between the oxide components of the composite semiconductor sensor. A separate section is devoted to new systems consisting of composite nanofibers of the core-shell type, the sensory characteristics of which depend on the transfer of electrons between the core and the shell in the nanofiber. It is demonstrated that by changing the nature of the components and their relative locations in such nanofibers, the sensitivity and selectivity of the sensor system can be tailored to various chemical compounds. Thus, the use of composite metal oxide systems can lead to improved efficiency and selectivity of conductometric sensors, and enable the development of sensor systems with the desired operating properties.
Abstract
Timepix4 is a 24.7 × 30.0 mm
2
hybrid pixel detector readout ASIC which has been designed to permit detector tiling on 4 sides. It consists of 448 × 512 pixels which can be bump bonded to a ...sensor with square pixels at a pitch of 55 µm. Like its predecessor, Timepix3, it can operate in data driven mode sending out information (Time of Arrival, ToA and Time over Threshold, ToT) only when a pixel has a hit above a pre-defined and programmable threshold. In this mode hits can be tagged to a time bin of <200 ps and Timepix4 can record hits correctly at incoming rates of ∼3.6 MHz/mm
2
/s. In photon counting (or frame-based) mode it can count incoming hits at rates of up to 5 GHz/mm
2
/s. In both modes data is output via between 2 and 16 serializers each running at a programmable data bandwidth of between 40 Mbps and 10 Gbps. The specifications, architecture and circuit implementation are described along with first electrical measurements and measurements with radioactive sources. In photon counting mode X-ray images have been taken at a threshold of 650 e
−
(with <10 masked pixels). In data driven mode images were taken of ToA/ToT data using a
90
Sr source at a threshold of 800 e
−
(with ∼120 masked pixels).
The effect of polyamine impregnation on the CO2 adsorption properties of two different porous carbons, one microporous and one mesoporous, was studied systematically. The pore filling during ...impregnation with polyamines was shown to result in a fraction of the unfilled micropore volume being blocked for gas adsorption. Thermal gravimetric analysis was used to compare the CO2 capacity at 0.1 bar with respect to the carbon support type, the amount of amine loading, and the type of amine. A 12 fold increase in the CO2 capacity was observed when the impregnated activated carbon was compared to the raw starting material. A heat of adsorption for amine impregnated support of ∼90 kJ mol−1 was found, clearly indicating a chemisorption mechanism. The mesoporous material provided a more efficient support for the amine to interact with the CO2. The interaction between low molecular weight amines and CO2 showed a more efficient utilization of the basic groups in comparison to high molecular weight species.
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•A study of two carbons, one microporous and one mesoporous, impregnated with amines.•Larger pores enable a more efficient interaction between CO2 and impregnated amine.•Lower molecular weight amines interact more efficiently with CO2 during adsorption.•Amine impregnation blocked a fraction of the micropore volume for gas adsorption.
The Timepix3, hybrid pixel detector (HPD) readout chip, a successor to the Timepix 1 chip, can record time-of-arrival (ToA) and time-over-threshold (ToT) simultaneously in each pixel. ToA information ...is recorded in a 14-bit register at 40 MHz and can be refined by a further 4 bits with a nominal resolution of 1.5625 ns (640 MHz). ToT is recorded in a 10-bit over-flow controlled counter at 40 MHz. Pixels can be programmed to record 14 bits of integral ToT and 10 bits of event counting, both at 40 MHz. A new architecture has been designed for sparse readout and can achieve a throughput of up to 40 Mhits/s/cm super(2). The digital design uses a mixture of commercial and custom standard cell libraries and was verified using Open Verification Methodology (OVM) and commercial timing analysis tools. The analog front-end and a voltage-controlled oscillator for 1.5625 ns timing resolution have been designed using full custom techniques.
Herein, we describe the identification, chemical optimization, and preclinical characterization of novel soluble guanylate cyclase (sGC) stimulators. Given the very broad therapeutic opportunities ...for sGC stimulators, new tailored molecules for distinct indications with specific pharmacokinetics, tissue distribution, and physicochemical properties will be required in the future. Here, we report the ultrahigh-throughput (uHTS)-based discovery of a new class of sGC stimulators from an imidazo1,2-apyridine lead series. Through the extensive and staggered optimization of the initial screening hit, liabilities such as potency, metabolic stability, permeation, and solubility could be substantially improved in parallel. These efforts resulted ultimately in the discovery of the new sGC stimulators 22 and 28. It turned out that BAY 1165747 (BAY-747, 28) could be an ideal treatment alternative for patients with hypertension, especially those not responding to standard anti-hypertensive therapy (resistant hypertension). BAY-747 (28) demonstrated sustained hemodynamic effects up to 24 h in phase 1 studies.
Methods of contemporary physical materials science are applied for the analysis of structural and phase states, tribological and mechanical properties of hypoeutectic silumin treated by electron ...beams with parameters as follow: energy density — 10–35 J/cm2, pulse duration — 10 µs, number of pulses — 3, pulse-repetition frequency — 0.3 Hz. The initial structure of silumin comprises grains of aluminium-based solid solution, eutectic grains, inclusions of silicon and intermetallic compounds with different shapes and sizes. Electron beam treatment (EBT) with energy density of 20–35 J/cm2 causes melting of the surface layer, dissolution of silicon inclusions and intermetallic compounds. A structure of high-speed cellular crystallization is formed, and submicro- and nanosize particles of the second phase are reprecipitated. An average size of crystallization cells are of 0.3–0.5 µm at the irradiated surface and of 0.4–0.8 µm on the lower edge of the layer with the cellular structure. The graded structure and phase states are analysed at a depth of up to 120 µm. The submicron grains of lamellar eutectic are detected at a depth of 15 µm. The lateral sizes of eutectic lamellae are within the range of 25–50 nm. The study indicates that nanohardness of irradiated silumin changes nonmonotonously and reaches its maximum at a depth of about 30 µm, which is approximately four times higher than hardness in the initial state. Hardness of the layer close to the irradiated surface (that is at a depth of about 5 µm) is higher by a factor of about 1.6 than that of as-cast silumin. The paper provides physical interpretation of the changes occurring in structure and properties during irradiation.
—The territorial structure and social organization of artificial groups of two subspecies of the midday gerbil (
Meriones meridianus nogaiorum, M. m. psammophilus
) were studied under seminatural ...conditions. No significant differences in the space use system of these subspecies were found. The structure of social interactions was identical in females but different in males:
M. m. nogaiorum
males exhibited a dominance hierarchy, while a despotic dominance was found in
M. m. psammophilus
males.
M. m. psammophilus
females also exhibited dominance hierarchy in enclosures, in addition, avoiding same-sex conspecifics seems to be a typical behavioral strategy of
M. m. psammophilus.
These findings support our suggestion that Tuvan–Mongolian
M. m. psammophilus
populations should be treated as a distinct species.
•The pearlite defect structure under severe plastic deformation is studied.•The formation of ‘channels of deformation’ is detected.•The formation of dynamic recrystallization grains is found.•The ...scalar and excess dislocation densities are estimated.•Their dependences on distance to surface of loading are established.
By the methods of transmission electron microscopy (TEM) at micro- and nanoscale levels the quantitative transformations of structure at a depth of 0, 2, 5, 10 mm along central axis and symmetry axis of fillet head of lengthy differentially quenched rails after severe plastic deformation (passed tonnage of 1770 mln. gross tons) are revealed. At a microscale level the transformation of cementite plates by newly formed grain boundaries absorption of carbon atoms from bulk carbides is established. At a nanoscale level the subgrain structure, being formed in surface layers, contains cementite nanodimensional particles, localized in junctions and along subgrain boundaries. This type of structure was formed as a result of dynamic recrystallization under megaplastic deformation being realized in a process of extremely long-term service of rails. The formation of so-called ‘channels of deformation’ is determined. It is shown that scalar and excess dislocation density in ferrite constituent of steel structure increases as the rail head surface is approached.
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