We report the detection of a faint point-like feature possibly related to ongoing planet-formation in the disk of the transition disk star HD 169142. The point-like feature has a Amag(L) ~ 6.4, at a ...separation of ~0".'11 and position angle ~0degrees. Given its lack of an H or KS counterpart despite its relative brightness, this candidate cannot be explained by purely photospheric emission and must be a disk feature heated by an as yet unknown source. Its extremely red colors make it highly unlikely to be a background object, but future multi-wavelength follow up is necessary for confirmation and characterization of this feature.
Orbital monitoring of M-type binaries is essential for constraining their fundamental properties. This is particularly useful in young systems, where the extended pre-main-sequence evolution can ...allow for precise isochronal dating. Here, we present the continued astrometric monitoring of the more than 200 binaries of the AstraLux Large Multiplicity Survey, building both on our previous work, archival data, and new astrometric data spanning the range of 2010-2012. The sample is very young overall-all included stars have known X-ray emission, and a significant fraction (18%) of them have recently also been identified as members of young moving groups in the solar neighborhood. We identify ~30 targets that both have indications of being young and for which an orbit either has been closed or appears possible to close in a reasonable time frame (a few years to a few decades). One of these cases, GJ 4326, is, however, identified as probably being substantially older than has been implied from its apparent moving group membership, based on astrometric and isochronal arguments. With further astrometric monitoring, these targets will provide a set of empirical isochrones, against which theoretical isochrones can be calibrated, and which can be used to evaluate the precise ages of nearby young moving groups.
The cloning of the jellyfish gfp (green fluorescent protein) gene and its alteration for expression in subcellular locations in transformed plant cells have resulted in new views of intracellular ...organization and dynamics. Fusions of GFP with entire proteins of known or unknown function have shown where the proteins are located and whether the proteins move from one compartment to another. GFP and variants with different spectral properties have been deliberately targeted to separate compartments to determine their size, shape, mobility, and dynamic changes during development or environmental response. Fluorescence Resonance Energy Transfer (FRET) between GFP variants can discern protein/ protein interactions. GFP has been used as a sensor to detect changes or differences in calcium, pH, voltage, metal, and enzyme activity. Photobleaching and photoactivation of GFP as well as fluorescence correlation spectroscopy can measure rates of diffusion and movement of GFP within or between compartments. This review covers past applications of these methods as well as promising developments in GFP imaging for understanding the functional organization of plant cells.
Among thermoplastics, polypropylene (PP) is outstanding with respect to its high versatility in terms of its tailoring property profiles for diversified applications, high resource and energy ...efficiency, environmentally friendly catalytic polymerization process, and recycling capability. However, additive manufacturing of PP by means of fused filament fabrication (FFF), also known as fused deposition modeling, suffers from several drawbacks like high shrinkage, massive warpage, and poor adhesion to common build plates. Herein, we overcome these problems by exploiting glass fiber-reinforced nanophase-separated PP reactor blends (Catalloy process resins). Catalloy is a polymerization process to create PP reactor blends containing dispersed ethylene/1-olefin copolymer rubber nanophases. A warpage quantification method confirms that 3D-printed Catalloy-based PP composites exhibit exceptionally low warpage and successfully compete with amorphous thermoplastics like acrylonitrile-butadiene styrene in printability, build plate adhesion, and printing precision. Microscopic imaging and the measurement of mechanical properties along and perpendicular to the 3D printing direction verify the rapid, highly efficient fusion of the deposited polymer strands. The resulting mechanical properties are very similar to those of injection-molded Catalloy-based composites even at high printing speeds. As evidenced by micro-computer tomography imaging, an unprecedented FFF process-mediated tuning of the fiber orientation is achieved. This allows for precisely tailoring both unidirectional and tuned multidirectional composites via computer design.
Individual plastids of vascular plants have generally been considered to be discrete autonomous entities that do not directly communicate with each other. However, transgenic plants in which the ...plastid stroma was labeled with green fluorescent protein (GFP), thin tubular projections emanated from individual plastids and sometimes connected to other plastids. Flow of GFP between interconnected plastids could be observed when a single plastid or an interconnecting plastid tubule was photobleached an the loss of green fluorescence by both plastids was seen. These tubules allow the exchange of molecules within an interplastid communication system, which may facilitate the coordination of plastid activities
Palladium catalysts have been widely adopted for organic synthesis and diverse industrial applications given their efficacy and safety, yet their biological in vivo use has been limited to date. Here ...we show that nanoencapsulated palladium is an effective means to target and treat disease through in vivo catalysis. Palladium nanoparticles (Pd-NPs) were created by screening different Pd compounds and then encapsulating bistri(2-furyl)phosphinepalladium(II) dichloride in a biocompatible poly(lactic-co-glycolic acid)-b-polyethyleneglycol platform. Using mouse models of cancer, the NPs efficiently accumulated in tumours, where the Pd-NP activated different model prodrugs. Longitudinal studies confirmed that prodrug activation by Pd-NP inhibits tumour growth, extends survival in tumour-bearing mice and mitigates toxicity compared to standard doxorubicin formulations. Thus, here we demonstrate safe and efficacious in vivo catalytic activity of a Pd compound in mammals.
VISION – Vienna survey in Orion Großschedl, Josefa Elisabeth; Alves, João; Teixeira, Paula S. ...
Astronomy and astrophysics (Berlin),
02/2019, Letnik:
622
Journal Article
Recenzirano
Odprti dostop
We have extended and refined the existing young stellar object (YSO) catalogs for the Orion A molecular cloud, the closest massive star-forming region to Earth. This updated catalog is driven by the ...large spatial coverage (18.3 deg2, ∼950 pc2), seeing limited resolution (∼0.7″), and sensitivity (Ks < 19 mag) of the ESO-VISTA near-infrared survey of the Orion A cloud (VISION). Combined with archival mid- to far-infrared data, the VISTA data allow for a refined and more robust source selection. We estimate that among previously known protostars and pre-main-sequence stars with disks, source contamination levels (false positives) are at least ∼6.4% and ∼2.3%, respectively, mostly due to background galaxies and nebulosities. We identify 274 new YSO candidates using VISTA/Spitzer based selections within previously analyzed regions, and VISTA/WISE based selections to add sources in the surroundings, beyond previously analyzed regions. The WISE selection method recovers about 59% of the known YSOs in Orion A’s low-mass star-forming part L1641, which shows what can be achieved by the all-sky WISE survey in combination with deep near-infrared data in regions without the influence of massive stars. The new catalog contains 2980 YSOs, which were classified based on the de-reddened mid-infrared spectral index into 188 protostars, 185 flat-spectrum sources, and 2607 pre-main-sequence stars with circumstellar disks. We find a statistically significant difference in the spatial distribution of the three evolutionary classes with respect to regions of high dust column-density, confirming that flat-spectrum sources are at a younger evolutionary phase compared to Class IIs, and are not a sub-sample seen at particular viewing angles.
Monoclonal antibodies (mAbs) targeting the immune checkpoint anti-programmed cell death protein 1 (aPD-1) have demonstrated impressive benefits for the treatment of some cancers; however, these drugs ...are not always effective, and we still have a limited understanding of the mechanisms that contribute to their efficacy or lack thereof. We used in vivo imaging to uncover the fate and activity of aPD-1 mAbs in real time and at subcellular resolution in mice. We show that aPD-1 mAbs effectively bind PD-1
tumor-infiltrating CD8
T cells at early time points after administration. However, this engagement is transient, and aPD-1 mAbs are captured within minutes from the T cell surface by PD-1
tumor-associated macrophages. We further show that macrophage accrual of aPD-1 mAbs depends both on the drug's Fc domain glycan and on Fcγ receptors (FcγRs) expressed by host myeloid cells and extend these findings to the human setting. Finally, we demonstrate that in vivo blockade of FcγRs before aPD-1 mAb administration substantially prolongs aPD-1 mAb binding to tumor-infiltrating CD8
T cells and enhances immunotherapy-induced tumor regression in mice. These investigations yield insight into aPD-1 target engagement in vivo and identify specific Fc/FcγR interactions that can be modulated to improve checkpoint blockade therapy.
Cells in complex organisms undergo frequent functional changes, but few methods allow comprehensive longitudinal profiling of living cells. Here we introduce scission-accelerated fluorophore exchange ...(SAFE), a method for multiplexed temporospatial imaging of living cells with immunofluorescence. SAFE uses a rapid bioorthogonal click chemistry to remove immunofluorescent signals from the surface of labeled cells, cycling the nanomolar-concentration reagents in seconds and enabling multiple rounds of staining of the same samples. It is non-toxic and functional in both dispersed cells and intact living tissues. We demonstrate multiparameter (n ≥ 14), non-disruptive imaging of murine peripheral blood mononuclear and bone marrow cells to profile cellular differentiation. We also show longitudinal multiplexed imaging of bone marrow progenitor cells as they develop into neutrophils over 6 days and real-time multiplexed cycling of living mouse hepatic tissues. We anticipate that SAFE will find broad utility for investigating physiologic dynamics in living systems.
The K-type binary star HD 102077 was proposed as a candidate member of the TW Hydrae association (TWA) which is a young (5−15 Myr) moving group in close proximity (~50 pc) to the solar system. The ...aim of this work is to verify this hypothesis by different means. We first combine diffraction-limited observations from the ESO NTT 3.5 m telescope in SDSS-i′ and SDSS-z′ passbands (three epochs) and ESO 3.6 m telescope in H-band (one epoch) with literature data to obtain a new, amended orbit fit of the visual binary. We then estimate the spectral types of both components from the i′ − z′ colours and reanalyse the Hipparcos parallax and proper motion taking the orbital motion into account. Moreover, we use two high-resolution spectra of HD 102077 obtained with the fibre-fed optical echelle spectrograph FEROS at the MPG/ESO 2.2 m telescope to determine the radial velocity and the lithium equivalent width (EW) of the system. Finally, we use all the information to discuss the kinematic properties of HD 102077 and to estimate the age of the system. The orbital elements of the HD 102077 trajectory are well constrained and we derive a total system mass of 2.6 ± 0.8 M⊙ and a semi-major axis of 14.9 ± 1.6 AU. From the i′ − z′ colours we infer an integrated spectral type of K2V, and individual spectral types of K0 ± 1 and K5 ± 1 for primary and secondary, respectively. The radial velocity corrected for the orbital motion of the system is 17.6 ± 2 km s-1. Even though the parallax determination from the Hipparcos data is not influenced by the orbital motion, the proper motion changes to μα ∗ cosδ = −137.84 ± 1.26 mas yr-1 and μδ = −33.53 ± 1.45 mas yr-1. With the resultant space motion, the probability of HD 102077 being a member of TWA is less than 1%. Furthermore, the lithium equivalent width of 200 ± 4 mÅ is consistent with an age between 30 Myr and 120 Myr and thus older than the predicted age of TWA. The comparison of HD 102077’s temperature and luminosity to isochrones supports this result. In conclusion, HD 102077’s age, galactic space motion, and position do not fit TWA or any other young moving group.
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