Publications

Abstract Blastocyst MHC is a recently identified mouse MHC class Ib gene, which is selectively expressed in blastocyst and placenta, and may be the mouse homolog of HLA-G gene the products of which have been implicated in protection of fetal trophoblasts from maternal NK cells and evasion of some tumor cells from NK cell attack. In this study, we identified two blastocyst MHC gene transcripts encoding a full-length α-chain (bc1) and an alternatively spliced form lacking the α2 domain (bc2), which may be homologous to HLA-G1 and HLA-G2, respectively. Both placenta and a teratocarcinoma cell line predominantly expressed the bc2 transcript. When these cDNAs were expressed in TAP-deficient RMA-S or TAP-sufficient RMA cells, only bc1 protein was expressed on the surface of RMA cells, but both bc1 and bc2 proteins were retained in the cytoplasm of RMA-S cells. Significantly, the RMA-S cells expressing either bc1 or bc2 were protected from lysis by NK cells in vitro. This protection was at least partly mediated by up-regulation of Qa-1b expression on the surface of RMA-S cells, which engaged the CD94/NKG2A inhibitory receptor on NK cells. More importantly, the bc1- or bc2-expressing RMA-S cells were significantly protected from NK cell-mediated rejection in vivo. These results suggested a role for blastocyst MHC in protecting TAP-deficient trophoblasts and tumor cells from NK cell attack in vivo.

We observed supernova 1987A (SN 1987A) with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) in 1999 September and again with the Advanced Camera for Surveys (ACS) on the HST in 2003 November. Our spectral observations cover ultraviolet (UV) and optical wavelengths from 1140 to 10266 Å, and our imaging observations cover UV and optical wavelengths from 2900 to 9650 Å. No point source is observed in the remnant. We obtain a limiting flux of F opt ≤ 1.6 × 10 -14 ergs s -1 cm -2 in the wavelength range 2900-9650 Å for any continuum emitter at the center of the supernova remnant (SNR). This corresponds to an intrinsic luminosity of L opt ≤ 5 × 10 33 ergs s -1. It is likely that the SNR contains opaque dust that absorbs UV and optical emission, resulting in an attenuation of ∼35% due to dust absorption in the SNR. Correcting for this level of dust absorption would increase our upper limit on the luminosity of a continuum source by a factor of 1.54. Taking into account dust absorption in the remnant, we find a limit of L opt ≤ 8 × 10 33 ergs s -1. We compare this upper bound with empirical evidence from point sources in other supernova remnants and with theoretical models for possible compact sources. We show that any survivor of a possible binary system must be no more luminous than an F6 main-sequence star. Bright young pulsars such as Kes 75 or the Crab pulsar are excluded by optical and X-ray limits on SN 1987A. Other nonplerionic X-ray point sources have luminosities similar to the limits on a point source in SN 1987 A; RCW 103 and Cas A are slightly brighter than the limits on SN 1987A, while Pup A is slightly fainter. Of the young pulsars known to be associated with SNRs, those with ages ≤5000 yr are all too bright in X-rays to be compatible with the limits on SN 1987A. Examining theoretical models for accretion onto a compact object, we find that spherical accretion onto a neutron star is firmly ruled out and that spherical accretion onto a black hole is possible only if there is a larger amount of dust absorption in the remnant than predicted. In the case of thin-disk accretion, our flux limit requires a small disk, no larger than 10 10 cm, with an accretion rate no more than 0.3 times the Eddington accretion rate. Possible ways to hide a surviving compact object include the removal of all surrounding material at early times by a photon-driven wind, a small accretion disk, or very high levels of dust absorption in the remnant. It will not be easy to improve substantially on our optical-UV limit for a point source in SN 1987A, although we can hope that a better understanding of the thermal infrared emission will provide a more complete picture of the possible energy sources at the center of SN 1987 A.

Abstract We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star–black hole (NSBH) merger GW190814. We searched the GW190814 localization region (19 deg 2 for the 90th percentile best localization), covering a total of 51 deg 2 and 94.6% of the two-dimensional localization region. Analyzing the properties of 189 transients that we consider as candidate counterparts to the NSBH merger, including their localizations, discovery times from merger, optical spectra, likely host galaxy redshifts, and photometric evolution, we conclude that none of these objects are likely to be associated with GW190814. Based on this finding, we consider the likely optical properties of an electromagnetic counterpart to GW190814, including possible kilonovae and short gamma-ray burst afterglows. Using the joint limits from our follow-up imaging, we conclude that a counterpart with an r -band decline rate of 0.68 mag day −1 , similar to the kilonova AT 2017gfo, could peak at an absolute magnitude of at most −17.8 mag (50% confidence). Our data are not constraining for “red” kilonovae and rule out “blue” kilonovae with M > 0.5 M ⊙ (30% confidence). We strongly rule out all known types of short gamma-ray burst afterglows with viewing angles <17° assuming an initial jet opening angle of ∼5.°2 and explosion energies and circumburst densities similar to afterglows explored in the literature. Finally, we explore the possibility that GW190814 merged in the disk of an active galactic nucleus, of which we find four in the localization region, but we do not find any candidate counterparts among these sources.

Evidence of effective methods for managing these illnesses has been reported, but it is not known how widely these methods or information technology are used in primary care outside the USA. The paper gives the first comprehensive nation-wide data on the use of evidence-based practices and computer systems for managing chronic illness in primary care in a European public health care system. It provides information allowing targeted actions which would improve quality of care which are low cost and high cost saving in the long term.

Data-intensive computing (DISC) frameworks scale by partitioning a job across a set of fault-tolerant tasks, then diffusing those tasks across large clusters. Multi-tenanted clusters must accommodate service-level objectives (SLO) in their resource model, often expressed as a maximum latency for allocating the desired set of resources to every job. When jobs are partitioned into tasks statically, a cluster cannot meet its SLOs while maintaining both high utilization and efficiency. Ideally, we want to give resources to jobs when they are free but would expect to reclaim them instantaneously when new jobs arrive, without losing work. DISC frameworks do not support such elasticity because interrupting running tasks incurs high overheads. Amoeba enables lightweight elasticity in DISC frameworks by identifying points at which running tasks of over-provisioned jobs can be safely exited, committing their outputs, and spawning new tasks for the remaining work. Effectively, tasks of DISC jobs are now sized dynamically in response to global resource scarcity or abundance. Simulation and deployment of our prototype shows that Amoeba speeds up jobs by 32% without compromising utilization or efficiency.

view Abstract Citations (30) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Gravitational Lens Candidate Discovered with the Hubble Space Telescope Maoz, Dan ; Bahcall, John N. ; Schneider, Donald P. ; Doxsey, Rodger ; Bahcall, Neta A. ; Filippenko, Alexei V. ; Goss, W. M. ; Lahav, Ofer ; Yanny, Brian Abstract We report evidence for gravitational lensing of the high-redshift (z = 3.8) quasar 1208+101, observed as part of the Snapshot Survey with the Hubble Space Telescope Planetary Camera. An HST V image taken on gyroscopes resolves the quasar into three point-source components, with the two fainter images having separations of 0.1" and 0.5" from the central bright component. A radio observation of the quasar with the Very Large Array at 2 cm shows that, like most quasars of this redshift, 1208+101 is radio-quiet. Based on positional information alone, the probability that the observed optical components are chance superpositions of Galactic stars is small, but not negligible. Analysis of a combined ground-based spectrum of all three components, using the relative brightnesses from the HST image, supports the lensing hypothesis. If all the components are lensed images of the quasar, the observed configuration cannot be reproduced by simple lens models. Future HST observations can test the lensing hypothesis for 1208+101. Publication: The Astrophysical Journal Pub Date: February 1992 DOI: 10.1086/186278 Bibcode: 1992ApJ...386L...1M Keywords: Gravitational Lenses; Hubble Space Telescope; Quasars; Radio Astronomy; Red Shift; Very Large Array (Vla); Milky Way Galaxy; Point Spread Functions; Radio Telescopes; Astrophysics; COSMOLOGY: GRAVITATIONAL LENSING; GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: 1208; 101 full text sources ADS | data products SIMBAD (5) NED (4) MAST (1) ESA (1)

1. The effects of purified diets containing 70% glucose or 70% fructose on the activation state of hepatic pyruvate dehydrogenase (PDHa), activity of mitochondrial PDH kinase, plasma triacylglycerols (TG) and hepatic lipogenesis de novo in rats were measured. 2. Plasma TG were significantly increased in the fructose-fed compared with the glucose-fed group (125 +/- 45 mg/dl versus 57 +/- 19 mg/dl; P less than 0.002) after 3-5 weeks on the diet despite less daily food intake. 3. Hepatic PDHa in fructose-fed rats was 144% of the value in glucose-fed rats (15.4 +/- 1.2% versus 10.7 +/- 0.5%; P less than 0.002), whereas cardiac muscle PDHa was not different (45.5 +/- 6.6% versus 41.0 +/- 7.8%). 4. Intrinsic hepatic PDH kinase activity was decreased to 34% of glucose-fed values by fructose feeding (-k = 3.56 +/- 0.39 versus 10.41 +/- 1.85 min-1; P less than 0.005). 5. The fractional contribution to very-low-density-lipoprotein palmitate from hepatic lipogenesis de novo, measured by a stable-isotope mass-spectrometric method, was 10.49 +/- 2.42% (n = 8) in fructose-fed rats versus 5.55 +/- 1.38% (n = 9) in glucose-fed rats (P less than 0.05), and 2.66 +/- 2.39% (n = 3) in chow-fed rats (P less than 0.05 versus fructose-fed group). The absolute contribution to circulating TG from lipogenesis de novo was also significantly higher in the fructose-fed than in the glucose-fed group (14.9 +/- 5.1 mg/dl versus 2.9 +/- 0.6 mg/dl; P less than 0.05) 6. Portal insulin concentrations were significantly higher in the fructose-fed rats (206 +/- 49 mu-units/ml versus 81 +/- 15 mu-units/ml; P less than 0.05). 7. In conclusion, dietary fructose appears to have a specific activating effect on hepatic PDH, mediated at least in part by inhibition of PDH kinase. These results are consistent with increased flux through hepatic PDH and synthesis of new fat, not just increased re-esterification of non-esterified fatty acids.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

New methods for the general asymmetric synthesis of sulfonimidamides are of great interest due to their applications in medicinal chemistry, agrochemical discovery, and academic research. We report a palladium-catalyzed cross-coupling method for the enantioselective aryl-carbonylation of sulfonimidamides. Using data science techniques, a virtual library of calculated bisphosphine ligand descriptors was used to guide reaction optimization by effectively sampling the catalyst chemical space. The optimized conditions identified using this approach provided the desired product in excellent yield and enantioselectivity. As the next step, a data science-driven strategy was also used to explore a diverse set of aryl and heteroaryl iodides, providing key information about the scope and limitations of the method. Furthermore, we tested a range of racemic sulfonimidamides for compatibility of this coupling partner. The developed method offers a general and efficient strategy for accessing enantioenriched sulfonimidamides, which should facilitate their application in industrial and academic settings.