Spectroscopic confirmation of two luminous galaxies at a redshift of 14.

The first observations of the James Webb Space Telescope (JWST) have revolutionized our understanding of the Universe by identifying galaxies at redshift z ≈ 13 (refs. 1-3). In addition, the discovery of many luminous galaxies at Cosmic Dawn (z > 10) has suggested that galaxies developed rapidly, in apparent tension with many standard models4-8. However, most of these galaxies lack spectroscopic confirmation, so their distances and properties are uncertain. Here we present JWST Advanced Deep Extragalactic Survey-Near-Infrared Spectrograph spectroscopic confirmation of two luminous galaxies at z = 14.32 - 0.20 + 0.08 and z = 13.90 ± 0.17. The spectra reveal ultraviolet continua with prominent Lyman-α breaks but no detected emission lines. This discovery proves that luminous galaxies were already in place 300 million years after the Big Bang and are more common than what was expected before JWST. The most distant of the two galaxies is unexpectedly luminous and is spatially resolved with a radius of 260 parsecs. Considering also the very steep ultraviolet slope of the second galaxy, we conclude that both are dominated by stellar continuum emission, showing that the excess of luminous galaxies in the early Universe cannot be entirely explained by accretion onto black holes. Galaxy formation models will need to address the existence of such large and luminous galaxies so early in cosmic history.

Association between transfusion of blood products and acute kidney injury following cardiac surgery.

BACKGROUND: Acute kidney injury (AKI) is a serious complication following cardiac surgery associated with increased mortality. Red blood cell transfusion enhances the risk of developing AKI. However, the impact of other blood products on AKI is virtually unexplored. The aim of this study was to explore if transfusion of red blood cells, fresh frozen plasma and platelets alone or in combination were associated with postoperative AKI. METHODS: Patients undergoing elective on-pump cardiac surgery were included (n = 1960) between 2012 to 2014. Transfusion data were collected intraoperatively and until the first postoperative day. AKI was classified according to the KDIGO criteria. Data were analysed using univariate and stepwise multiple logistic regression with adjustment for clinical risk factors and complementary blood products. RESULTS: AKI was observed in 542 patients (27.7%). In univariate analysis and following adjustment for clinical risk factors, administration of red blood cells, freshfrozen plasma and platelets were all independently associated with KDIGO stage 2-3. Following additional adjustment for complementary blood products, only red blood cell transfusion remained significantly associated with AKI. A dose-dependent association between volume of red blood cells and degree of AKI severity was observed. CONCLUSION: Transfusion of all blood products in a dose-dependent manner increased the risk for AKI. However, in multivariate analysis combining all blood products, only red blood cell transfusion remained significantly associated with AKI development.

Duration of critically low oxygen delivery is associated with acute kidney injury after cardiac surgery.

BACKGROUND: Acute kidney injury is a serious complication following cardiac surgery associated with mortality. Restricted oxygen delivery is a potential risk factor for acute kidney injury. The aim of this study was to investigate the impact of the duration of low oxygen delivery (<272 mL  min-1  m-2 ), during cardiopulmonary bypass on kidney function. METHODS: Patients undergoing coronary artery bypass graft surgery ± valve repair were included n = 1968. Oxygen delivery was monitored during cardiopulmonary bypass. Data were explored using multiple regression analyses regarding association between low oxygen delivery and renal replacement therapy (RRT), acute kidney injury (AKI) and post-operative peak serum creatinine (PPSC). RESULTS: Post-operative peak serum creatinine, incidence of acute kidney injury, and need for dialysis increased in a dose-dependent manner in relation to duration of a mean oxygen delivery <272 mL  min-1  m-2 . Using multiple regression analyses, only exposure for at least 30 minutes was independently associated with increased PPSC and AKI. In contrast, both short (1-5 min, OR: 2.58 [1.20, 5.54]; P = .015) and at least 30-minute (OR: 2.85 [1.27-6.41]; P = .011) exposure to low DO2 were both independently associated with the need for RRT. CONCLUSION: A low oxygen delivery during cardiopulmonary bypass was in a dose-dependent manner associated with an increased risk of renal injury.