Beyond spectroscopy. II. Stellar parameters for over twenty million stars in the northern sky from SAGES DR1 and Gaia DR3

We present precise photometric estimates of stellar parameters, including effective temperature, metallicity, luminosity classification, distance, and stellar age, for nearly 26 million stars using the methodology developed in the first paper of this series, based on the stellar colors from the Stellar Abundances and Galactic Evolution Survey (SAGES) DR1 and Gaia EDR3. The optimal design of stellar-parameter sensitive $uv$ filters by SAGES has enabled us to determine photometric-metallicity estimates down to $-3.5$, similar to our previous results with the SkyMapper Southern Survey (SMSS), yielding a large sample of over five million metal-poor (MP; [Fe/H]$\le -1.0$) stars and nearly one million very metal-poor (VMP; [Fe/H]$\le -2.0$) stars. The typical precision is around $0.1$ dex for both dwarf and giant stars with [Fe/H]$>-1.0$, and 0.15-0.25/0.3-0.4 dex for dwarf/giant stars with [Fe/H]$<-1.0$. Using the precise parallax measurements and stellar colors from Gaia, effective temperature, luminosity classification, distance and stellar age are further derived for our sample stars. This huge data set in the Northern sky from SAGES, together with similar data in the Southern sky from SMSS, will greatly advance our understanding of the Milky Way, in particular its formation and evolution.Comment: 14 pages, 14 figures, 3 tables, accepted by ApJ. arXiv admin note: text overlap with arXiv:2104.1415

The Protective Effect of Propofol Against Ischemia–Reperfusion Injury in the Interlobar Arteries: Reduction of Abnormal Cx43 Expression as a Possible Mechanism

Background/Aims: This experimental study aims to observe whether the protective effect of propofol against renal ischemia–reperfusion injury (IRI) in the rat interlobar artery occurs through altered expression of the gap junction protein connexin 43 (Cx43). Methods: This study randomly divided male Sprague Dawley (SD) rats into an untreated control group, a sham-operated control group (sham group), an ischemia–reperfusion group (IR group), a propofol group (propofol+IR group) and a fat emulsion group (Intralipid group). The ischemia/reperfusion model was prepared through resection of the right kidney and noninvasive arterial occlusion of the left kidney. Forty-five minutes after renal ischemia–reperfusion, an automatic biochemical analyzer was employed to measure blood urea nitrogen (BUN) and serum creatinine (SCr); changes in renal tissue pathology were observed using hematoxylin and eosin (HE) staining, and the vasomotor activity of the interlobar artery was detected using a pressure mechanogram technique. The protein expression of Cx43 in renal artery cross-sections was determined through western blotting. Results: The experimental study confirmed that the BUN and SCr of rats markedly increased after ischemia–reperfusion injury; additionally, we observed some coagulation necrosis and shedding of cells, some solidification of nuclear chromatin, degeneration of cytoplasmic vacuoles, high renal interstitial vascular congestion and obvious inflammatory cell infiltration, characterized by focal hemorrhages. Furthermore, the contraction activity of the renal interlobar artery greatly decreased, and the tension of the arteries in the renal lobe increased remarkably. After the gap junction blocking agents 2-APB and Gap27 were applied, the systolic velocity of blood vessels and the vascular contraction rate both decreased. In addition, the expression of Cx43 in kidney tissues increased markedly. The damage was more severe after 24 h of ischemic reperfusion than after only 4 h. However, after pretreatment with propofol, regardless of whether ischemia–reperfusion was applied for 4 h or 24 h, the previously increased expression of Cx43 decreased obviously, and all forms of renal damage were reversed. Conclusion: Our research suggests new ways for propofol to relieve ischemia–reperfusion injury by decreasing the abnormal expression of the gap junction protein Cx43. This study reveals a novel mechanism for the action of propofol against IRI, and we hope this finding will lead to new treatments for IRI

Noema formIng Cluster survEy (NICE): Discovery of a starbursting galaxy group with a radio-luminous core at z=3.95

The study of distant galaxy groups and clusters at the peak epoch of star formation is limited by the lack of a statistically and homogeneously selected and spectroscopically confirmed sample. Recent discoveries of concentrated starburst activities in cluster cores have opened a new window to hunt for these structures based on their integrated IR luminosities. Hereby we carry out the large NOEMA (NOrthern Extended Millimeter Array) program targeting a statistical sample of infrared-luminous sources associated with overdensities of massive galaxies at z>2, the Noema formIng Cluster survEy (NICE). We present the first result from the ongoing NICE survey, a compact group at z=3.95 in the Lockman Hole field (LH-SBC3), confirmed via four massive (M_star>10^10.5M_sun) galaxies detected in CO(4-3) and [CI](1-0) lines. The four CO-detected members of LH-SBC3 are distributed over a 180 kpc physical scale, and the entire structure has an estimated halo mass of ~10^13Msun and total star formation rate (SFR) of ~4000Msun/yr. In addition, the most massive galaxy hosts a radio-loud AGN with L_1.4GHz, rest = 3.0*10^25W/Hz. The discovery of LH-SBC3 demonstrates the feasibility of our method to efficiently identify high-z compact groups or forming cluster cores. The existence of these starbursting cluster cores up to z~4 provides critical insights into the mass assembly history of the central massive galaxies in clusters.Comment: 7 pages, 7 figures, submitted to A&