High-temperature copper oxide superconductors consist of stacked CuO
planes, with electronic band structures and magnetic excitations that are primarily two-dimensional
, but with superconducting ...coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state
within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides
reveals their charge origin, that is, without mixing with magnetic components
. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO
planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems
and argued to play a substantial part in mediating high-temperature superconductivity
.
Glycolysis is critical for cancer stem cell reprogramming; however, the underlying regulatory mechanisms remain elusive. Here, we show that pyruvate dehydrogenase kinase 1 (PDK1) is enriched in ...breast cancer stem cells (BCSCs), whereas depletion of PDK1 remarkably diminishes ALDH
subpopulations, decreases stemness-related transcriptional factor expression, and inhibits sphere-formation ability and tumor growth. Conversely, high levels of PDK1 enhance BCSC properties and are correlated with poor overall survival. In mouse xenograft tumor, PDK1 is accumulated in hypoxic regions and activates glycolysis to promote stem-like traits. Moreover, through screening hypoxia-related long non-coding RNAs (lncRNAs) in PDK1-positive tissue, we find that lncRNA H19 is responsible for glycolysis and BCSC maintenance. Furthermore, H19 knockdown decreases PDK1 expression in hypoxia, and ablation of PDK1 counteracts H19-mediated glycolysis and self-renewal ability in vitro and in vivo. Accordingly, H19 and PDK1 expression exhibits strong correlations in primary breast carcinomas. H19 acting as a competitive endogenous RNA sequesters miRNA let-7 to release Hypoxia-inducible factor 1α, leading to an increase in PDK1 expression. Lastly, aspirin markedly attenuates glycolysis and cancer stem-like characteristics by suppressing both H19 and PDK1. Thus, these novel findings demonstrate that the glycolysis gatekeeper PDK1 has a critical role in BCSC reprogramming and provides a potential therapeutic strategy for breast malignancy.
We utilize Sloan Digital Sky Survey imaging and spectroscopy of 653,000 star-forming galaxies at z60.1 to study the relation between stellar mass and gas-phase metallicity. We derive gas-phase oxygen ...abundances and stellar masses using new techniques that make use of the latest stellar evolutionary synthesis and photoionization models. We find a tight (c0.1 dex) correlation between stellar mass and metallicity spanning over 3 orders of magnitude in stellar mass and a factor of 10 in metallicity. The relation is relatively steep from 10 super(8.5) to 10 super(10.5) M sub( )h70 super(-2), in good accord with known trends between luminosity and metallicity, but flattens above 10 super(10.5) M sub( ). We use indirect estimates of the gas mass based on the Ha luminosity to compare our data to predictions from simple closed box chemical evolution models. We show that metal loss is strongly anticorrelated with baryonic mass, with low-mass dwarf galaxies being 5 times more metal depleted than L* galaxies at z60.1. Evidence for metal depletion is not confined to dwarf galaxies but is found in galaxies with masses as high as 10 super(10) M sub( ). We interpret this as strong evidence of both the ubiquity of galactic winds and their effectiveness in removing metals from galaxy potential wells.
Biochars are being increasingly applied in soil for carbon sequestration, fertility improvement, as well as contamination remediation. Phosphoric acid (H3PO4) pretreatment is a method for biochar ...modification, but the mechanism is not yet fully understood. In this work, biochars and the raw biomass were treated by H3PO4 prior to pyrolysis. Due to an acid catalysis and crosslink, the micropores of the pretreated particles were much more than those without H3PO4 pretreatment, resulting in the dramatical enhancement of specific surface areas of the pretreated particles. Crystalline cellulose (CL) exhibited a greater advantage in the formation of micropores than of amorphous lignin (LG) with H3PO4 modification. The formation mechanisms of micropores were: (a) H+ from H3PO4 contributes to micropores generation via H+ catalysis process; (b) the organic phosphate bridge protected the carbon skeleton from micropore collapse via the crosslinking of phosphate radical. The sorption capacities to carbamazepine (CBZ) and bisphenol A (BPA) increased after H3PO4 modification, which is ascribed to the large hydrophobic surface areas and more abundant micropores. Overall, H3PO4 pretreatment produced biochars with large surface area and high abundance of porous structures. Furthermore, the H3PO4 modified biochars can be applied as high adsorbing material as well as P-rich fertilizer.
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•Phosphoric acid treatment enhances surface area due to the generated micropores.•Cellulose produces more micropores than lignin after phosphoric acid treatment.•Acid catalysis and crosslinking contribute to micropore generation.•Large surface area and pore volume of the treated biochars enhanced the sorption.•Phosphoric acid modified biochars could be applied in P-depleted soil.
H3PO4 pretreatment enhances the sorption of organic pollutants on biochars by generation of micropores.
Context. The internal dynamics of ultra-compact dwarf galaxies (UCDs) has attracted increasing attention, with most of the UCDs studied to date located in the Virgo cluster. Aims. Our aim is to ...perform a comprehensive census of the internal dynamics of UCDs in the Fornax cluster, and to shed light on the nature of the interface between star clusters and galaxies. Methods. We obtained high-resolution spectra of 23 Fornax UCDs with –$10.4>M_V>-13.5$ mag ($10^6<{ M/M_{\sun}<10^8}$), using FLAMES/Giraffe at the VLT. This is the largest homogeneous data set of UCD internal dynamics assembled to date. We derive dynamical $M/L$ ratios for 15 UCDs covered by HST imaging. Results. In the MV–σ plane, UCDs with $M_V<-12$ mag are consistent with the extrapolated Faber-Jackson relation for luminous elliptical galaxies, while most of the fainter UCDs are closer to the extrapolated globular cluster (GC) relation. At a given metallicity, Fornax UCDs have, on average, $M/L$ ratios lower by 30–40% than Virgo UCDs, suggesting possible differences in age or dark matter content between Fornax and Virgo UCDs. For our sample of Fornax UCDs we find no significant correlation between $M/L$ ratio and mass. We combine our data with available $M/L$ ratio measurements of compact stellar systems with $10^4<{ M/M_{\sun}}<10^8$ M, and normalise all $M/L$ estimates to solar metallicity. We find that UCDs ($M \gtrsim 2 \times 10^6~M_{\sun}$) have $M/L$ ratios twice as large as GCs ($M\lesssim 2 \times 10^6~M_{\sun}$). We argue that dynamical evolution has probably had only a small effect on the current $M/L$ ratios of objects in the combined sample, implying that stellar population models tend to under-predict dynamical $M/L$ ratios of UCDs and over-predict those of GCs. Considering the scaling relations of stellar spheroids, we find that UCDs align well along the “Fundamental Manifold”. UCDs can be considered the small-scale end of the galaxy sequence in this context. The alignment for UCDs is especially clear for $r_{\rm e} \gtrsim 7$ pc, which corresponds to dynamical relaxation times that exceed a Hubble time. In contrast, globular clusters exhibit a broader scatter and do not appear to align along the manifold. Conclusions. We argue that UCDs are the smallest dynamically un-relaxed stellar systems, with $M\gtrsim 2 \times 10^6~M_{\sun}$ and $7\lesssim{r_{\rm e}/{\rm pc}} \lesssim 100$. Future studies should aim at explaining the elevated $M/L$ ratios of UCDs and the environmental dependence of their properties.
The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band H
α
+ NII imaging survey carried out with MegaCam at the Canada-France-Hawaii Telescope. During pilot ...observations taken in the spring of 2016 we observed NGC 4330, an intermediate mass (
M
*
≃ 10
9.8
M
⊙
) edge-on star forming spiral currently falling into the core of the Virgo cluster. While previous H
α
observations showed a clumpy complex of ionised gas knots outside the galaxy disc, new deep observations revealed a low surface brightness ~10 kpc tail exhibiting a peculiar filamentary structure. The filaments are remarkably parallel to one another and clearly indicate the direction of motion of the galaxy in the Virgo potential. Motivated by the detection of these features which indicate ongoing gas stripping, we collected literature photometry in 15 bands from the far-UV to the far-IR and deep optical long-slit spectroscopy using the FORS2 instrument at the ESO Very Large Telescope. Using a newly developed Monte Carlo code that jointly fits spectroscopy and photometry, we reconstructed the star formation histories in apertures along the major axis of the galaxy. Our results have been validated against the output of CIGALE, a fitting code which has been previously used for similar studies. We found a clear outside-in gradient with radius of the time when the quenching event started: the outermost radii were stripped ~500 Myr ago, while the stripping reached the inner 5 kpc from the centre in the last 100 Myr. Regions at even smaller radii are currently still forming stars fueled by the presence of HI and H
2
gas. When compared to statistical studies of the quenching timescales in the local Universe we find that ram pressure stripping of the cold gas is an effective mechanism to reduce the transformation times for galaxies falling into massive clusters. Future systematic studies of all the active galaxies observed by VESTIGE in the Virgo cluster will extend these results to a robust statistical framework.
Patients with cancer are purported to have poor COVID-19 outcomes. However, cancer is a heterogeneous group of diseases, encompassing a spectrum of tumour subtypes. The aim of this study was to ...investigate COVID-19 risk according to tumour subtype and patient demographics in patients with cancer in the UK.
We compared adult patients with cancer enrolled in the UK Coronavirus Cancer Monitoring Project (UKCCMP) cohort between March 18 and May 8, 2020, with a parallel non-COVID-19 UK cancer control population from the UK Office for National Statistics (2017 data). The primary outcome of the study was the effect of primary tumour subtype, age, and sex and on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prevalence and the case–fatality rate during hospital admission. We analysed the effect of tumour subtype and patient demographics (age and sex) on prevalence and mortality from COVID-19 using univariable and multivariable models.
319 (30·6%) of 1044 patients in the UKCCMP cohort died, 295 (92·5%) of whom had a cause of death recorded as due to COVID-19. The all-cause case–fatality rate in patients with cancer after SARS-CoV-2 infection was significantly associated with increasing age, rising from 0·10 in patients aged 40–49 years to 0·48 in those aged 80 years and older. Patients with haematological malignancies (leukaemia, lymphoma, and myeloma) had a more severe COVID-19 trajectory compared with patients with solid organ tumours (odds ratio OR 1·57, 95% CI 1·15–2·15; p<0·0043). Compared with the rest of the UKCCMP cohort, patients with leukaemia showed a significantly increased case–fatality rate (2·25, 1·13–4·57; p=0·023). After correction for age and sex, patients with haematological malignancies who had recent chemotherapy had an increased risk of death during COVID-19-associated hospital admission (OR 2·09, 95% CI 1·09–4·08; p=0·028).
Patients with cancer with different tumour types have differing susceptibility to SARS-CoV-2 infection and COVID-19 phenotypes. We generated individualised risk tables for patients with cancer, considering age, sex, and tumour subtype. Our results could be useful to assist physicians in informed risk–benefit discussions to explain COVID-19 risk and enable an evidenced-based approach to national social isolation policies.
University of Birmingham and University of Oxford.
Using the Hubble Space Telescope (HST) Wide Field Camera (WFC) of the Advanced Camera for Surveys (ACS), we have obtained deep (V, I) photometry of an outer halo field in NGC 5128, to a limiting ...magnitude of I 29. Our photometry directly reveals the core helium burning stellar population (the "red clump" or horizontal branch) in a giant E/S0 galaxy for the first time. The color-magnitude diagram displays a very wide red giant branch (RGB), an asymptotic giant branch (AGB) bump, and the red clump; no noticeable population of blue horizontal branch stars is present, confirming previous suggestions that old, very metal-poor population is not ubiquitous in the halo of this galaxy. From the upper RGB we derive the metallicity distribution, which we find to be very broad and moderately metal-rich, with average M/H = -0.64 and dispersion 0.49 dex. The metallicity distribution function is virtually identical to that found in other halo fields observed previously with HST, but with an enhanced metal-rich population that was partially missed in the previous surveys due to V-band incompleteness for these very red stars. Combining the metallicity-sensitive colors of the RGB stars with the metallicity- and age-sensitive features of the AGB bump and the red clump, we infer the average age of the halo stars to be 68 sub(-3.5) super(+3) Gyr. As part of our study, we present an empirical calibration of the ACS F606W and F814W filters to the standard V and I bands, achieved with ground-based observations of the same field made from the EMMI camera of the New Technology Telescope of the ESO La Silla Observatory.
We present the color distributions of globular cluster (GC) systems for 100 early-type galaxies observed in the ACS Virgo Cluster Survey, the deepest and most homogeneous survey of this kind to date. ...On average, galaxies at all luminosities in our study (-22 < M sub(B) < -15) appear to have bimodal or asymmetric GC color distributions. Almost all galaxies possess a component of metal-poor GCs, with the average fraction of metal-rich GCs ranging from 15% to 60% and increasing with luminosity. The colors of both subpopulations correlate with host galaxy luminosity and color, with the red GCs having a steeper slope. To convert color to metallicity, we introduce a preliminary (g - z)-Fe/H relation calibrated to Galactic, M49, and M87 GCs. This relation is nonlinear, with a steeper slope for Fe/H -0.8. As a result, the metallicities of the metal-poor and metal-rich GCs vary similarly with respect to galaxy luminosity and stellar mass, with relations of Fe/H sub(MP) 8 L super(0.16c0.04) 8 M super(0.17c0.04)* and Fe/H sub(MR) 8 L super(0.26c0.03) 8 M super(0.22c0.03)*, respectively. Although these relations are shallower than the mass-metallicity relation predicted by wind models and observed for dwarf galaxies, they are very similar to the relation observed for star-forming galaxies in the same mass range. The offset between the two GC populations is approximately 1 dex across 3 orders of magnitude in mass, suggesting a nearly universal amount of enrichment between the formation of the two populations of GCs. We also find that although the metal-rich GCs show a larger dispersion in color, it is the metal-poor GCs that have an equal or larger dispersion in metallicity. The similarity in the M sub(*)-Fe/H relations for the two populations implies that the conditions of GC formation for metal-poor and metal-rich GCs could not have been too different. Like the color-magnitude relation, these relations derived from globular clusters present stringent constraints on the formation and evolution of early-type galaxies.
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