Monodisperse spherical Ni nanoparticles with diameters of 2 nm, 5 nm, and 7 nm were synthesized from the thermal decomposition of a Ni–oleylamine complex. Ni nanocrystal superlattices were generated ...via the controlled evaporation of solvent (see Figure). The nanoparticles were successfully used as catalysts for the Suzuki coupling reaction, and were readily oxidized to produce NiO nanoparticles.
Since its invention in 2006, the broadband chirped pulse Fourier transform spectrometer has transformed the field of microwave spectroscopy. The technique enables the collection of a ≥10 GHz ...bandwidth spectrum in a single shot of the spectrometer, which allows broadband, high-resolution microwave spectra to be acquired several orders of magnitude faster than what was previously possible. We discuss the advantages and challenges associated with the technique and look back on the first ten years of chirped pulse Fourier transform spectroscopy. In addition to enabling faster-than-ever structure determination of increasingly complex species, the technique has given rise to an assortment of entirely new classes of experiments, ranging from chiral sensing by three-wave mixing to microwave detection of multichannel reaction kinetics. However, this is only the beginning. Future generations of microwave experiments will make increasingly creative use of frequency-agile pulse sequences for the coherent manipulation and interrogation of molecular dynamics.
The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor νover ¯_{e} by comparing their prompt signal spectra measured in two identical ...near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor νover ¯_{e} around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor νover ¯_{e} is observed in the deficit of the observed number of νover ¯_{e}. Based on the measured far-to-near ratio of prompt spectra, we obtain sin^{2}2θ_{13}=0.082±0.009(stat)±0.006(syst) and |Δm_{ee}^{2}|=2.62_{-0.23}^{+0.21}(stat)_{-0.13}^{+0.12}(syst)×10^{-3} eV^{2}.
We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively ...short event timescale of tE ∼ 7.5 days. The Einstein radius is unusually small, θE = 0.065 mas, implying that the lens system either has very low mass or lies much closer to the microlensed source than the Sun, or both. A Bayesian analysis yields component masses and source-lens distance , implying that this is a brown-dwarf/Jupiter system that probably lies in the Galactic bulge, a location that is also consistent with the relatively low lens-source relative proper motion = 3.2 0.5 mas yr−1. The projected companion-host separation is , indicating that the planet is placed beyond the snow line of the host, i.e., asl ∼ 0.12 au. Planet formation scenarios combined with the small companion-host mass ratio q ∼ 0.016 and separation suggest that the companion could be the first discovery of a giant planet that formed in a protoplanetary disk around a brown-dwarf host.
Some heptamethine cyanine dyes accumulate in solid tumors in vivo and persist there for several days. The reasons why they accumulate and persist in tumors were incompletely defined, but explanations ...based on uptake into cancer cells via organic anion transporting polypeptides (OATPs) have been widely discussed. All cyanine-based “tumor-seeking dyes” have a chloride centrally placed on the heptamethine bridge (a “meso-chloride”). We were intrigued and perplexed by the correlation between this particular functional group and tumor uptake, so the following study was designed. It features four dyes (1-Cl, 1-Ph, 5-Cl, and 5-Ph) with complementary properties. Dye 1-Cl is otherwise known as MHI-148, and 1-Ph is a close analog wherein the meso-chloride has been replaced by a phenyl group. Data presented here shows that both 1-Cl and 1-Ph form noncovalent adducts with albumin, but only 1-Cl can form a covalent one. Both dyes 5-Cl and 5-Ph have a methylene (CH2) unit replaced by a dimethylammonium functionality (N+Me2). Data presented here shows that both these dyes 5 do not form tight noncovalent adducts with albumin, and only 5-Cl can form a covalent one (though much more slowly than 1-Cl). In tissue culture experiments, uptake of dyes 1 is more impacted by the albumin in the media than by the pan-OATP uptake inhibitor (BSP) that has been used to connect uptake of tumor-seeking dyes in vivo with the OATPs. Uptake of 1-Cl in media containing fluorescein-labeled albumin gave a high degree of colocalization of intracellular fluorescence. No evidence was found for the involvement of OATPs in uptake of the dyes into cells in media containing albumin. In an in vivo tumor model, only the two dyes that can form albumin adducts (1-Cl and 5-Cl) gave intratumor fluorescence that persisted long enough to be clearly discerned over the background (∼4 h); this fluorescence was still observed at 48 h. Tumors could be imaged with a higher contrast if 5-Cl is used instead of 1-Cl, because 5-Cl is cleared more rapidly from healthy tissues. Overall, the evidence is consistent with in vitro and in vivo results and indicates that the two dyes in the test series that accumulate in tumors and persist there (1-Cl and 5-Cl, true tumor-seeking dyes) do so as covalent albumin adducts trapped in tumor tissue via uptake by some cancer cells and via the enhanced permeability and retention (EPR) effect.
The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six 2.8 ... GW(th) reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is 0.920±0.009(stat)±0.014(syst). From this deficit, we determine sin(2)2θ(13)=0.113±0.013(stat)±0.019(syst) based on a rate-only analysis.
Current microlensing surveys are sensitive to free-floating planets down to Earth-mass objects. All published microlensing events attributed to unbound planets were identified based on their short ...timescale (below two days), but lacked an angular Einstein radius measurement (and hence lacked a significant constraint on the lens mass). Here, we present the discovery of a Neptune-mass free-floating planet candidate in the ultrashort (tE = 0.320 0.003 days) microlensing event OGLE-2016-BLG-1540. The event exhibited strong finite-source effects, which allowed us to measure its angular Einstein radius of θE = 9.2 0.5 as. There remains, however, a degeneracy between the lens mass and distance. The combination of the source proper motion and source-lens relative proper motion measurements favors a Neptune-mass lens located in the Galactic disk. However, we cannot rule out that the lens is a Saturn-mass object belonging to the bulge population. We exclude stellar companions up to ∼15 au.
We analyze an ensemble of microlensing events from the 2015 Spitzer microlensing campaign, all of which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations ...from Spitzer and the ground yield measurements of the microlensing parallax vector , from which compact constraints on the microlens properties are derived, including 25% uncertainties on the lens mass and distance. With the current sample, we demonstrate that the majority of microlenses are indeed in the mass range of M dwarfs. The planet sensitivities of all 41 events in the sample are calculated, from which we provide constraints on the planet distribution function. In particular, assuming a planet distribution function that is uniform in , where q is the planet-to-star mass ratio, we find a 95% upper limit on the fraction of stars that host typical microlensing planets of 49%, which is consistent with previous studies. Based on this planet-free sample, we develop the methodology to statistically study the Galactic distribution of planets using microlensing parallax measurements. Under the assumption that the planet distributions are the same in the bulge as in the disk, we predict that ∼1/3 of all planet detections from the microlensing campaigns with Spitzer should be in the bulge. This prediction will be tested with a much larger sample, and deviations from it can be used to constrain the abundance of planets in the bulge relative to the disk.
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