We report on the petrology and geochemistry of the Northwest Africa 2737 (NWA 2737) meteorite that was recovered from the Morrocan Sahara in 2000. It is the second member of the chassignite subclass ...of the SNC (Shergotitte-Nakhlite-Chassignite) group of meteorites that are thought to have originated on Mars. It consists of black olivine- and spinel-cumulate crystals (89.7 and 4.6
wt%, respectively), with intercumulus pyroxenes (augite 3.1
wt% and pigeonite–orthopyroxene 1.0
wt%), analbite glass (1.6
wt%) and apatite (0.2
wt%). Unlike Chassigny, plagioclase has not been observed in NWA 2737. Olivine crystals are rich in Mg, and highly equilibrated (
Fo
=
78.7
±
0.5
mol%). The black color of olivine grains may be related to the strong shock experienced by the meteorite as revealed by the deformation features observed on the macroscopic to the atomic scale. Chromite is zoned from core to rim from Cr
83.4Uv
3.6Sp
13.0 to Cr
72.0Uv
6.9Sp
21.1. Pyroxene compositional trends are similar to those described for Chassigny except that they are richer in Mg. Compositions range from En
78.5Wo
2.7Fs
18.8 to En
76.6Wo
3.2Fs
20.2 for the orthopyroxene, from En
73.5Wo
8.0Fs
18.5 to En
64.0Wo
22.1Fs
13.9for pigeonite, and from En
54.6Wo
32.8Fs
12.6 to En
46.7Wo
44.1Fs
9.2 for augite. Bulk rock oxygen isotope compositions confirm that NWA 2737 is a new member of the martian meteorite clan (Δ
17O
=
0.305
±
0.02‰,
n
=
2). REE abundances measured in NWA 2737 mineral phases are similar to those in Chassigny and suggest a genetic relationship between these two rocks. However, the parent melt of NWA 2737 was less evolved and had a lower Al abundance.
Context. With an orbital distance comparable to that of Saturn in the solar system, β Pictoris b is the closest (semi-major axis ≃9 au) exoplanet that has been imaged to orbit a star. Thus it offers ...unique opportunities for detailed studies of its orbital, physical, and atmospheric properties, and of disk-planet interactions. With the exception of the discovery observations in 2003 with NaCo at the Very Large Telescope (VLT), all following astrometric measurements relative to β Pictoris have been obtained in the southwestern part of the orbit, which severely limits the determination of the planet’s orbital parameters. Aims. We aimed at further constraining β Pictoris b orbital properties using more data, and, in particular, data taken in the northeastern part of the orbit. Methods. We used SPHERE at the VLT to precisely monitor the orbital motion of beta β Pictoris b since first light of the instrument in 2014. Results. We were able to monitor the planet until November 2016, when its angular separation became too small (125 mas, i.e., 1.6 au) and prevented further detection. We redetected β Pictoris b on the northeast side of the disk at a separation of 139 mas and a PA of 30° in September 2018. The planetary orbit is now well constrained. With a semi-major axis (sma) of a = 9.0 ± 0.5 au (1σ), it definitely excludes previously reported possible long orbital periods, and excludes β Pictoris b as the origin of photometric variations that took place in 1981. We also refine the eccentricity and inclination of the planet. From an instrumental point of view, these data demonstrate that it is possible to detect, if they exist, young massive Jupiters that orbit at less than 2 au from a star that is 20 pc away.
Genetic methods can guide and improve the management of recreational mixed‐stock fisheries by informing stock‐specific estimates of harvest. We applied genetic stock identification and ...parentage‐based tagging to a recreational Chinook Salmon Oncorhynchus tshawytscha fishery in the Columbia River to illustrate the value of genetic analysis in management. We sampled landed catch in 2017 and 2018, assigned the fish to genetic reporting groups, explored temporal trends in harvest composition within and between seasons, and assessed the accuracy and precision of genetic methods against estimates from conventional tagging methodology. The genetic stock identification and parentage‐based tagging produced concordant stock assignments, and the harvest composition estimates were validated with independent data. High assignment rates, relative to expended sampling effort, and precise harvest composition estimates with adequate sample sizes demonstrate that both genetic methods can be complementary, effective tools in advancing harvest assessment and recreational fisheries management. The success of genetic stock identification and parentage‐based tagging supports the expanded application of genetics to similar fisheries, potentially alongside existing or emerging assessment methods, and guides future improvements in data collection and analysis.
In this work, the toxicological assessment towards filamentous fungi (Penicillium sp.) as model eukaryotic organisms of sixteen ionic liquids (containing an imidazolium, pyridinium, or cholinium ...cation) is presented. Amongst these fungi are members which show much higher tolerance towards ionic liquids than any other microorganism so far studied. Furthermore, guided by the paradigm that the choice of an ionic liquid as catalyst can alter the outcome of a given chemical reaction, the ability of ionic liquids to alter the metabolic profile in fungi was studied. The metabolic footprint, as investigated by electrospray ionisation mass spectrometry, revealed that fungal cultures respond to specific ionic liquids by changing their cell biochemistry, resulting in an altered pattern of secondary metabolites.
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•TLL immobilized on superparamagnetic nanoparticles (Fe3O4) functionalized with PEI.•TLL immobilized on superparamagnetic nanoparticles functionalized with APTES.•New strategy to ...obtain of medicament precursors with biocatalyst from SPMN supports.•Efficiency in kinetic resolution of medicament precursor, 50% (conversion).•Efficiency in kinetic resolution of medicament precursor, e.e.=99%.
Superparamagnetic iron oxide nanoparticles (Fe3O4) were prepared by the co-precipitation method and functionalized with 3-amino-propyltriethoxysilane (APTES) or branched-polyethylenimine (PEI). After that, two parallels methods to immobilize the lipase from Thermomyces lanuginosus (TLL) were performed: the first one by ionic exchange and the second one by covalent attachment after the functionalization of the support with glutaraldehyde (GA). X-ray powder diffraction, magnetometry and infrared spectroscopy analysis were used to characterize the TLL preparations. These analyses showed that all samples presented superparamagnetic properties even after the immobilization procedure. The SPMN (superparamagnetic nanoparticle) @APTES covalent preparation had around 450min of half-life time at pH 7.0 and 70°C while that of the free enzyme was 46min. These biocatalysts were evaluated in the kinetic resolution of rac-1-methyl-2-(2,6-dimethylphenoxy)ethyl acetate in different co-solvents (acetonitrile, isopropanol, ethyl ether and tetrahydrofuran). The best results were for the enzyme/substrate ratio of 2:1, in the presence of the ethyl ether or THF (20% v/v both) at 30°C during 24h with the SPMN@PEI-TLL biocatalyst. The conversion attained was 50% and the enantiomeric excess of the product was 99%. The new SPMN support are an excellent strategy to easy recovery of the biocatalyst by applying a magnetic field.
Abstract
We carried out spectroscopic monitoring of 21 low-redshift Seyfert 1 galaxies using the Kast double spectrograph on the 3 m Shane telescope at Lick Observatory from 2016 April to 2017 May. ...Targeting active galactic nuclei (AGNs) with luminosities of
λ
L
λ
(5100 Å) ≈ 10
44
erg s
−1
and predicted H
β
lags of ∼20–30 days or black hole masses of 10
7
–10
8.5
M
⊙
, our campaign probes luminosity-dependent trends in broad-line region (BLR) structure and dynamics as well as to improve calibrations for single-epoch estimates of quasar black hole masses. Here we present the first results from the campaign, including H
β
emission-line light curves, integrated H
β
lag times (8–30 days) measured against
V
-band continuum light curves, velocity-resolved reverberation lags, line widths of the broad H
β
components, and virial black hole mass estimates (10
7.1
–10
8.1
M
⊙
). Our results add significantly to the number of existing velocity-resolved lag measurements and reveal a diversity of BLR gas kinematics at moderately high AGN luminosities. AGN continuum luminosity appears not to be correlated with the type of kinematics that its BLR gas may exhibit. Follow-up direct modeling of this data set will elucidate the detailed kinematics and provide robust dynamical black hole masses for several objects in this sample.
Although Stat1 is required for many IFN-dependent responses, recent work has shown that IFNγ functions independently of Stat1 to affect the growth of tumor cells or immortalized fibroblasts. We now ...demonstrate that both IFNγ and IFNα/β regulate proliferative responses in cells of the mononuclear phagocyte lineage derived from Stat1-null mice. Using both representational difference analysis and gene arrays, we show that IFNγ exerts its Stat1-independent actions on mononuclear phagocytes by regulating the expression of many genes. This result was confirmed by monitoring changes in expression and function of the corresponding gene products. Regulation of the expression of these genes requires the IFNγ receptor and Jak1. The physiologic relevance of IFN-dependent, Stat1-independent signaling was demonstrated by monitoring antiviral responses in Stat1-null mice. Thus, the IFN receptors engage alternative Stat1-independent signaling pathways that have important physiological consequences.
While the regional climate is the primary selection pressure for whether a plant strategy can survive, however, competitive interactions strongly affect the relative abundances of plant strategies ...within communities. Here, we investigate the relative importance of competition and perturbations on the development of vegetation community structure. To do so, we develop DIVE (Dynamics and Interactions of VEgetation), a simple general model that links plant strategies to their competitive dynamics, using growth and reproduction characteristics that emerge from climatic constraints. The model calculates population dynamics based on establishment, mortality, invasion and exclusion in the presence of different strengths of perturbations, seed and resource competition. The highest levels of diversity were found in simulations without competition as long as mortality is not too high. However, reasonable successional dynamics were only achieved when resource competition is considered. Under high levels of competition, intermediate levels of perturbations were required to obtain coexistence. Since succession and coexistence are observed in plant communities, we conclude that the DIVE model with competition and intermediate levels of perturbation represents an adequate way to model population dynamics. Because of the simplicity and generality of DIVE, it could be used to understand vegetation structure and functioning at the global scale and the response of vegetation to global change.
The blood-brain barrier (BBB) is a specialized vascular interface that restricts the entry of many compounds into brain. This is accomplished through the sealing of vascular endothelial cells ...together with tight junction proteins to prevent paracellular diffusion. In addition, the BBB has a high degree of expression of numerous efflux transporters which actively extrude compounds back into blood. However, when a metastatic lesion develops in brain the vasculature is typically compromised with increases in passive permeability (blood-tumor barrier; BTB). What is not well documented is to what degree active efflux retains function at the BTB despite the changes observed in passive permeability. In addition, there have been previous reports documenting both increased and decreased expression of P-glycoprotein (P-gp) in lesion vasculature. Herein, we simultaneously administer a passive diffusion marker ((14)C-AIB) and a tracer subject to P-gp efflux (rhodamine 123) into a murine preclinical model of brain metastases of breast cancer. We observed that the metastatic lesions had similar expression (p > 0.05; n = 756-1214 vessels evaluated) at the BBB and the BTB. Moreover, tissue distribution of R123 was not significantly (p > 0.05) different between normal brain and the metastatic lesion. It is possible that the similar expression of P-gp on the BBB and the BTB contribute to this phenomenon. Additionally we observed P-gp expression at the metastatic cancer cells adjacent to the vasculature which may also contribute to reduced R123 uptake into the lesion. The data suggest that despite the disrupted integrity of the BTB, efflux mechanisms appear to be intact, and may be functionally comparable to the normal BBB. The BTB is a significant hurdle to delivering drugs to brain metastasis.
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