Direct and Enantioselective Organocatalytic α-Chlorination of Aldehydes

The first direct enantioselective catalytic α-chlorination of aldehydes has been accomplished. The use of enamine catalysis has provided a new organocatalytic strategy for the enantioselective chlorination of aldehydes to generate α-chloro aldehydes, an important chiral synthon for chemical and medicinal agent synthesis. The use of imidazolidinone 3 as the asymmetric catalyst has been found to mediate the halogenation of a large variety of aldehyde substrates with the perchlorinated quinone 1 serving as the electrophilic chlorinating reagent. A diverse spectrum of aldehyde substrates can also be accommodated in this new organocatalytic transformation. The capacity of catalyst 3 to override the inherent bias of resident stereogenicity in the chlorination of enantiopure β-chiral aldehydes is also described. Catalyst quantities of 5 mol % were generally employed in this study

The First Enantioselective Organocatalytic Mukaiyama−Michael Reaction: A Direct Method for the Synthesis of Enantioenriched γ-Butenolide Architecture

The first enantioselective organocatalytic Mukaiyama−Michael reaction using α,β-unsaturated aldehydes has been accomplished. The use of iminium catalysis has provided a new strategy for the enantioselective addition of 2-silyloxy furans to unsaturated aldehydes to generate a variety of butenolide systems, an important chiral synthon found among many natural isolates. The (2S,5S)-5-benzyl-2-tert-butyl-imidazolidinone amine catalyst has been found to mediate the conjugate addition of a wide variety of substituted and unsubstituted silyloxy furans to unsaturated aldehydes. A diverse range of aldehyde substrates can be accommodated in this new organocatalytic transformation. Application of this new asymmetric technology to the enantioselective total synthesis of spiculisporic acid and the corresponding 5-epi-spiculisporic acid analogue is also discussed

An ALMA Constraint on the GSC 6214-210 B Circum-Substellar Accretion Disk Mass

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of GSC 6214-210 A and B, a solar-mass member of the 5-10 Myr Upper Scorpius association with a 15 $\pm$ 2 Mjup companion orbiting at $\approx$330 AU (2.2"). Previous photometry and spectroscopy spanning 0.3-5 $\mu$m revealed optical and thermal excess as well as strong H$\alpha$ and Pa~$\beta$ emission originating from a circum-substellar accretion disk around GSC 6214-210 B, making it the lowest mass companion with unambiguous evidence of a subdisk. Despite ALMA's unprecedented sensitivity and angular resolution, neither component was detected in our 880 $\mu$m (341 GHz) continuum observations down to a 3-$\sigma$ limit of 0.22 mJy/beam. The corresponding constraints on the dust mass and total mass are <0.15 Mearth and <0.05 Mjup, respectively, or <0.003% and <0.3% of the mass of GSC 6214-210 B itself assuming a 100:1 gas-to-dust ratio and characteristic dust temperature of 10-20 K. If the host star possesses a putative circum-stellar disk then at most it is a meager 0.0015% of the primary mass, implying that giant planet formation has certainly ceased in this system. Considering these limits and its current accretion rate, GSC 6214-210 B appears to be at the end stages of assembly and is not expected to gain any appreciable mass over the next few Myr.Comment: Accepted to ApJ

The Direct and Enantioselective Organocatalytic α-Oxidation of Aldehydes

The first direct enantioselective catalytic α-oxidation of carbonyls has been accomplished. The use of enamine catalysis has provided a new organocatalytic strategy for the enantioselective oxyamination of aldehydes, to generate α-oxyaldehydes, important chiral synthons for natural product and medicinal agent synthesis. The use of l-proline as the asymmetric catalyst has been found to mediate the oxidation of a large variety of aldehyde substrates with nitrosobenzene serving as the electrophilic oxidant. A diverse spectrum of aldehyde substrates can also be accommodated in this new organocatalytic transformation. While catalyst quantities of 2 mol % were generally employed in this study, successful oxidations conducted using catalyst loadings as low as 0.5 mol % are described

Reporter\u27s Occupation and Source of Adverse Device Event Reports Contained in the FDA\u27s MAUDE Database

Introduction: A review of the medical device adverse events submitted to the United States Food & Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) database was undertaken to determine the major sources of the information. Methods: The reporter’s occupation and source of the medical device report were determined for acquisition dates Jan 1, 1997 to Dec 31, 2018. A total of 7,766,737 adverse event records were analyzed. Results: 96.6% of reports originated with the manufacturer. Patients (patients/family/friend) were the most frequent submitter of reports directly to the FDA, almost five times as often as physicians. Nurses submitted reports directly to the FDA 2.77 times as often as physicians. Only 0.49% of physician reports were submitted directly to the FDA, representing 0.09% of total MAUDE reports. Conclusion: Increasing physician reporting directly to the FDA and MAUDE through the MedWatch reporting system is an imperative. Incorporating information from the perspective of the physician has the potential of increasing the quality of the data and improving the reliability of post-market surveillance

Via-SEES: Variability in Atmosphere from Solar Energetic Electrons

Variability In Atmosphere from Solar Energetic Electron Study (VIA-SEES) is a hybrid science mission and technology development campaign from the Earth and Planetary Exploration Technologies (EPET) program at the University of Hawai’i. It is oriented around establishing a direct correlation between Solar Radiation Events (SREs) and Variability in Atmospheric gases, specifically Nitric and Nitrous Oxide, as well as Ozone. The mission is intended to fly on a 3U CubeSat and will collect a data set which is multimodal. To achieve robust performance, a variety of techniques are employed to make the science data set easier to interpret by an analyst. It is important to consider the format of the data sets, which is generally given by the instrument collecting the data. To allow for a better establishment of an anticoincidence, meaning that there is a precise correlation between 2 readings on the same index, a systems engineering approach is taken. This is as the science mission requirements should drive the design of the mission. A comprehensive approach is taken in the design of the VIA-SEES spacecraft, to maximize the scientific value of the mission

A Spatially Resolved Inner Hole in the Disk around GM Aurigae

We present 0.3 arcsec resolution observations of the disk around GM Aurigae with the Submillimeter Array (SMA) at a wavelength of 860 um and with the Plateau de Bure Interferometer at a wavelength of 1.3 mm. These observations probe the distribution of disk material on spatial scales commensurate with the size of the inner hole predicted by models of the spectral energy distribution. The data clearly indicate a sharp decrease in millimeter optical depth at the disk center, consistent with a deficit of material at distances less than ~20 AU from the star. We refine the accretion disk model of Calvet et al. (2005) based on the unresolved spectral energy distribution (SED) and demonstrate that it reproduces well the spatially resolved millimeter continuum data at both available wavelengths. We also present complementary SMA observations of CO J=3-2 and J=2-1 emission from the disk at 2" resolution. The observed CO morphology is consistent with the continuum model prediction, with two significant deviations: (1) the emission displays a larger CO J=3-2/J=2-1 line ratio than predicted, which may indicate additional heating of gas in the upper disk layers; and (2) the position angle of the kinematic rotation pattern differs by 11 +/- 2 degrees from that measured at smaller scales from the dust continuum, which may indicate the presence of a warp. We note that photoevaporation, grain growth, and binarity are unlikely mechanisms for inducing the observed sharp decrease in opacity or surface density at the disk center. The inner hole plausibly results from the dynamical influence of a planet on the disk material. Warping induced by a planet could also potentially explain the difference in position angle between the continuum and CO data sets.Comment: 12 pages, 6 figures, accepted for publication in Ap

Are language production problems apparent in adults who no longer meet diagnostic criteria for attention-deficit/hyperactivity disorder?

In this study, we examined sentence production in a sample of adults (N = 21) who had had attention-deficit/hyperactivity disorder (ADHD) as children, but as adults no longer met DSM-IV diagnostic criteria (APA, 2000). This “remitted” group was assessed on a sentence production task. On each trial, participants saw two objects and a verb. Their task was to construct a sentence using the objects as arguments of the verb. Results showed more ungrammatical and disfluent utterances with one particular type of verb (i.e., participle). In a second set of analyses, we compared the remitted group to both control participants and a “persistent” group, who had ADHD as children and as adults. Results showed that remitters were more likely to produce ungrammatical utterances and to make repair disfluencies compared to controls, and they patterned more similarly to ADHD participants. Conclusions focus on language output in remitted ADHD, and the role of executive functions in language production