ABSTRACT We present the first year of Hubble Space Telescope imaging of the unique supernova (SN) "Refsdal," a gravitationally lensed SN at z = 1.488 0.001 with multiple images behind the galaxy ...cluster MACS J1149.6+2223. The first four observed images of SN Refsdal (images S1-S4) exhibited a slow rise (over ∼150 days) to reach a broad peak brightness around 2015 April 20. Using a set of light curve templates constructed from SN 1987A-like peculiar Type II SNe, we measure time delays for the four images relative to S1 of 4 4 (for S2), 2 5 (S3), and 24 7 days (S4). The measured magnification ratios relative to S1 are 1.15 0.05 (S2), 1.01 0.04 (S3), and 0.34 0.02 (S4). None of the template light curves fully captures the photometric behavior of SN Refsdal, so we also derive complementary measurements for these parameters using polynomials to represent the intrinsic light curve shape. These more flexible fits deliver fully consistent time delays of 7 2 (S2), 0.6 3 (S3), and 27 8 days (S4). The lensing magnification ratios are similarly consistent, measured as 1.17 0.02 (S2), 1.00 0.01 (S3), and 0.38 0.02 (S4). We compare these measurements against published predictions from lens models, and find that the majority of model predictions are in very good agreement with our measurements. Finally, we discuss avenues for future improvement of time delay measurements-both for SN Refsdal and for other strongly lensed SNe yet to come.
The prediction of a supersonic solar wind
was first confirmed by spacecraft near Earth
and later by spacecraft at heliocentric distances as small as 62 solar radii
. These missions showed that plasma ...accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy
. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams
. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii
, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age
.
ABSTRACT We have acquired Hubble Space Telescope (HST) and Very Large Telescope near-infrared spectra and images of supernova (SN) Refsdal after its discovery as an Einstein cross in fall 2014. The ...HST light curve of SN Refsdal has a shape consistent with the distinctive, slowly rising light curves of SN 1987A-like SNe, and we find strong evidence for a broad H P-Cygni profile and Na I D absorption in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, largely powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show broad and strong H and Na I D absorption. From the grism spectrum, we measure an H expansion velocity consistent with those of SN 1987A-like SNe at a similar phase. The luminosity, evolution, and Gaussian profile of the H emission of the WFC3 and X-shooter spectra, separated by ∼2.5 months in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, photometry of SN Refsdal favors bluer B − V and V − R colors and one of the largest luminosities for the assumed range of potential magnifications. The evolution of the light curve at late times will provide additional evidence about the potential existence of any substantial circumstellar material. Using MOSFIRE and X-shooter spectra, we estimate a subsolar host-galaxy metallicity (8.3 0.1 dex and <8.4 dex, respectively) near the explosion site.
The primary aim of this study was to evaluate the antitumor efficacy of the bromodomain inhibitor JQ1 in pancreatic ductal adenocarcinoma (PDAC) patient-derived xenograft (tumorgraft) models. A ...secondary aim of the study was to evaluate whether JQ1 decreases expression of the oncogene c-Myc in PDAC tumors, as has been reported for other tumor types. We used five PDAC tumorgraft models that retain specific characteristics of tumors of origin to evaluate the antitumor efficacy of JQ1. Tumor-bearing mice were treated with JQ1 (50 mg/kg daily for 21 or 28 days). Expression analyses were performed with tumors harvested from host mice after treatment with JQ1 or vehicle control. An nCounter PanCancer Pathways Panel (NanoString Technologies) of 230 cancer-related genes was used to identify gene products affected by JQ1. Quantitative RT-PCR, immunohistochemistry and immunoblots were carried out to confirm that changes in RNA expression reflected changes in protein expression. JQ1 inhibited the growth of all five tumorgraft models (P<0.05), each of which harbors a KRAS mutation; but induced no consistent change in expression of c-Myc protein. Expression profiling identified CDC25B, a regulator of cell cycle progression, as one of the three RNA species (TIMP3, LMO2 and CDC25B) downregulated by JQ1 (P<0.05). Inhibition of tumor progression was more closely related to decreased expression of nuclear CDC25B than to changes in c-Myc expression. JQ1 and other agents that inhibit the function of proteins with bromodomains merit further investigation for treating PDAC tumors. Work is ongoing in our laboratory to identify effective drug combinations that include JQ1.
There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, ...which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in
Rn and
Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.
With the advent of new wide-field, high-cadence optical transient surveys, our understanding of the diversity of core-collapse supernovae has grown tremendously in the last decade. However, the ...pre-supernova evolution of massive stars, which sets the physical backdrop to these violent events, is theoretically not well understood and difficult to probe observationally. Here we report the discovery of the supernova iPTF 13dqy = SN 2013fs a mere ∼3 h after explosion. Our rapid follow-up observations, which include multiwavelength photometry and extremely early (beginning at ∼6 h post-explosion) spectra, map the distribution of material in the immediate environment (<, ~1015 cm) of the exploding star and establish that it was surrounded by circumstellar material (CSM) that was ejected during the final ∼1 yr prior to explosion at a high rate, around 10-3 solar masses per year. The complete disappearance of flash-ionized emission lines within the first several days requires that the dense CSM be confined to within <, ~1015 cm, consistent with radio non-detections at 70-100 days. The observations indicate that iPTF 13dqy was a regular type II supernova; thus, the finding that the probable red supergiant progenitor of this common explosion ejected material at a highly elevated rate just prior to its demise suggests that pre-supernova instabilities may be common among exploding massive stars.
Polymeric gels have been an important category for material scientists due its versatile structural features. Hence, hydrogels are being used to reduce excess production water in oil reservoirs. In ...this work, cross-linked partially hydrolyzed polyacrylamide (HPAM) composite hydrogels impregnated with bentonite clay (Bent) and bentonite clay modified (Orgbentent) with the surfactant hexadecyltrimethylammonium bromide were synthesized and characterized as a sealing agent in high water producing permeable zones in the petroleum industry. The concept of utilizing hydrophobically modified clay as an inorganic additive in the hydrogel matrix emanates from the fact that this additive exhibit greater interaction with the polymer chains. These interactions can promote the inherent properties of the hydrogel. Polyethyleneimine (PEI) was chosen as the cross-linking agent. HPAM/PEI conventional hydrogels and HPAM/PEI/Bent and HPAM/PEI/Orgbent at 100 mg·L–1 clay were synthesized. The developed hydrogels were characterized by a hybrid rheometer and Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) instruments. Rheological results reveal that the (HPAM/PEI/Bent-3 and HPAM/PEI/Orgbent-3) composite hydrogels showed higher elastic modulus (G′) and durability in the studied conditions (stable at 30 days) than conventional ones (HPAM/PEI), indicating the dispersion and reinforcing effect of clay. The functional groups of these hydrogels were confirmed by FTIR, and TGA demonstrated the structural reinforcement due to the presence of the clays, which had lower weight loss than the conventional hydrogel. The hydrogel morphologies were analyzed by SEM, and the results corroborated with those obtained by TGA, indicating better structural reinforcement when using organophilic clay.
Bosutinib is approved for newly diagnosed Philadelphia chromosome-positive (Ph+) chronic phase (CP) chronic myeloid leukemia (CML) and for Ph+ CP, accelerated (AP), or blast (BP) phase CML after ...prior treatment with tyrosine kinase inhibitors (TKIs). In the ongoing phase 4 BYOND study (NCT02228382), 163 CML patients resistant/intolerant to prior TKIs (n = 156 Ph+ CP CML, n = 4 Ph+ AP CML, n = 3 Ph-negative/BCR-ABL1+ CML) received bosutinib 500 mg once daily (starting dose). As of ≥1 year after last enrolled patient (median treatment duration 23.7 months), 56.4% of Ph+ CP CML patients remained on bosutinib. Primary endpoint of cumulative confirmed major cytogenetic response (MCyR) rate by 1 year was 75.8% in Ph+ CP CML patients after one or two prior TKIs and 62.2% after three prior TKIs. Cumulative complete cytogenetic response (CCyR) and major molecular response (MMR) rates by 1 year were 80.6% and 70.5%, respectively, in Ph+ CP CML patients overall. No patient progressed to AP/BP on treatment. Across all patients, the most common treatment-emergent adverse events were diarrhea (87.7%), nausea (39.9%), and vomiting (32.5%). The majority of patients had confirmed MCyR by 1 year and MMR by 1 year, further supporting bosutinib use for Ph+ CP CML patients resistant/intolerant to prior TKIs.
PDF
