Co-hydrolysis of hydrothermal and dilute acid pretreated populus slurries to support development of a high-throughput pretreatment system

Background The BioEnergy Science Center (BESC) developed a high-throughput screening method to rapidly identify low-recalcitrance biomass variants. Because the customary separation and analysis of liquid and solids between pretreatment and enzymatic hydrolysis used in conventional analyses is slow, labor-intensive and very difficult to automate, a streamlined approach we term 'co-hydrolysis' was developed. In this method, the solids and liquid in the pretreated biomass slurry are not separated, but instead hydrolysis is performed by adding enzymes to the whole pretreated slurry. The effects of pretreatment method, severity and solids loading on co-hydrolysis performance were investigated. Results For hydrothermal pretreatment at solids concentrations of 0.5 to 2%, high enzyme protein loadings of about 100 mg/g of substrate (glucan plus xylan) in the original poplar wood achieved glucose and xylose yields for co-hydrolysis that were comparable with those for washed solids. In addition, although poplar wood sugar yields from co-hydrolysis at 2% solids concentrations fell short of those from hydrolysis of washed solids after dilute sulfuric acid pretreatment even at high enzyme loadings, pretreatment at 0.5% solids concentrations resulted in similar yields for all but the lowest enzyme loading. Conclusions Overall, the influence of severity on susceptibility of pretreated substrates to enzymatic hydrolysis was clearly discernable, showing co-hydrolysis to be a viable approach for identifying plant-pretreatment-enzyme combinations with substantial advantages for sugar production

Unprecedented X-ray Emission from the Fast Blue Optical Transient AT2022tsd

We present the X-ray monitoring campaign of AT2022tsd in the time range $\delta t_{rest} = 23 - 116$ d rest-frame since discovery. With an initial 0.3-10 keV X-ray luminosity of $L_x \approx 10^{44}$ erg s$^{-1}$ at $\delta t_{rest}\approx$ 23 d, AT2022tsd is the most luminous FBOT to date and rivals even the most luminous GRBs. We find no statistical evidence for spectral evolution. The average X-ray spectrum is well described by an absorbed simple power-law spectral model with best-fitting photon index $\Gamma = 1.89 ^{+0.09}_{-0.08}$ and marginal evidence at the 3$\sigma$ confidence level for intrinsic absorption $NH_{int}\approx 4\times10^{19}$ cm$^{-2}$. The X-ray light-curve behavior can be either interpreted as a power-law decay $L_x\propto t^{\alpha}$ with $\alpha\approx -2$ and superimposed X-ray variability, or as a broken power-law with a steeper post-break decay as observed in other FBOTs such as AT2018cow. We briefly compare these results to accretion models of TDEs and GRB afterglow models.Comment: 5 pages, 1 figure, 1 table. Submitted to RNAA

Metabolic Effects Of Duodenojejunal Bypass Surgery In A Rat Model Of Type 1 Diabetes

Background Metabolic surgery has beneficial metabolic effects, including remission of type 2 diabetes. We hypothesized that duodenojejunal bypass (DJB) surgery can protect against development of type 1 diabetes (T1D) by enhancing regulation of cellular and molecular pathways that control glucose homeostasis. Methods BBDP/Wor rats, which are prone to develop spontaneous autoimmune T1D, underwent loop DJB (n = 15) or sham (n = 15) surgery at a median age of 41 days, before development of diabetes. At T1D diagnosis, a subcutaneous insulin pellet was implanted, oral glucose tolerance test was performed 21 days later, and tissues were collected 25 days after onset of T1D. Pancreas and liver tissues were assessed by histology and RT-qPCR. Fecal microbiota composition was analyzed by 16S V4 sequencing. Results Postoperatively, DJB rats weighed less than sham rats (287.8 vs 329.9 g,P = 0.04). In both groups, 14 of 15 rats developed T1D, at similar age of onset (87 days in DJB vs 81 days in sham,P = 0.17). There was no difference in oral glucose tolerance, fasting and stimulated plasma insulin and c-peptide levels, and immunohistochemical analysis of insulin-positive cells in the pancreas. DJB rats needed 1.3 +/- 0.4 insulin implants vs 1.9 +/- 0.5 in sham rats (P = 0.002). Fasting and glucose stimulated glucagon-like peptide 1 (GLP-1) secretion was elevated after DJB surgery. DJB rats had reduced markers of metabolic stress in liver. After DJB, the fecal microbiome changed significantly, including increases inAkkermansiaandRuminococcus, while the changes were minimal in sham rats. Conclusion DJB does not protect against autoimmune T1D in BBDP/Wor rats, but reduces the need for exogenous insulin and facilitates other metabolic benefits including weight loss, increased GLP-1 secretion, reduced hepatic stress, and altered gut microbiome

Scary Barbie: An Extremely Energetic, Long-Duration Tidal Disruption Event Candidate Without a Detected Host Galaxy at z = 0.995

We report multi-wavelength observations and characterization of the ultraluminous transient AT 2021lwx (ZTF20abrbeie; aka ``Barbie'') identified in the alert stream of the Zwicky Transient Facility (ZTF) using a Recommender Engine For Intelligent Transient Tracking (REFITT) filter on the ANTARES alert broker. From a spectroscopically measured redshift of 0.995, we estimate a peak observed pseudo-bolometric luminosity of log (L$_{\text{max}} / [\text{erg}/\text{s}]$) = 45.7 from slowly fading ztf-$\it{g}$ and ztf-$r$ light curves spanning over 1000 observer-frame days. The host galaxy is not detected in archival Pan-STARRS observations ($g > 23.3$ mag), implying a lower limit to the outburst amplitude of more than 5 mag relative to the quiescent host galaxy. Optical spectra from Lick and Keck Observatories exhibit strong emission lines with narrow cores from the H Balmer series and ultraviolet semi-forbidden lines of Si III] $\lambda$1892, C III] $\lambda$1909, and C II] $\lambda$2325. Typical nebular lines in AGN spectra from ions such as [O II] and [O III] are not detected. These spectral features, along with the smooth light curve that is unlike most AGN flaring activity, and the luminosity that exceeds any observed or theorized supernova, lead us to conclude that AT 2021lwx is most likely an extreme tidal disruption event (TDE). Modeling of ZTF photometry with MOSFiT suggests that the TDE was between a $\approx 14 M_{\odot}$ star and a supermassive black hole of mass $M_{\text{BH}} \sim$ $10^{8} M_{\odot}$. Continued monitoring of the still-evolving light curve along with deep imaging of the field once AT 2021lwx has faded can test this hypothesis and potentially detect the host galaxy.Comment: 15 pages, 4 figures, 1 Table; Version as published in The Astrophysical Journal Letters. Observations of AT 2021lwx published in the paper can be found at https://bsubraya.github.io/research

Roaring to softly whispering : X-Ray emission after ∼3.7 yr at the location of the transient AT2018cow and implications for accretion-powered scenarios

We present the first deep X-ray observations of luminous fast blue optical transient (LFBOT) AT 2018cow at ∼3.7 yr since discovery, together with the reanalysis of the observation at δ t ∼ 220 days. X-ray emission is significantly detected at a location consistent with AT 2018cow. The very soft X-ray spectrum and sustained luminosity are distinct from the spectral and temporal behavior of the LFBOT in the first ∼100 days and would possibly signal the emergence of a new emission component, although a robust association with AT 2018cow can only be claimed at δ t ∼ 220 days, while at δ t ∼ 1350 days contamination of the host galaxy cannot be excluded. We interpret these findings in the context of the late-time panchromatic emission from AT 2018cow, which includes the detection of persistent, slowly fading UV emission with ν L ν ≈ 1039 erg s−1. Similar to previous works (and in analogy with arguments for ultraluminous X-ray sources), these late-time observations are consistent with thin disks around intermediate-mass black holes (with M • ≈ 103–104 M ☉) accreting at sub-Eddington rates. However, differently from previous studies, we find that smaller-mass black holes with M • ≈ 10–100 M ☉ accreting at ≳the Eddington rate cannot be ruled out and provide a natural explanation for the inferred compact size (R out ≈ 40 R ☉) of the accretion disk years after the optical flare. Most importantly, irrespective of the accretor mass, our study lends support to the hypothesis that LFBOTs are accretion-powered phenomena and that, specifically, LFBOTs constitute electromagnetic manifestations of super-Eddington accreting systems that evolve to ≲Eddington over a ≈100-day timescale

Radio analysis of SN2004C reveals an unusual CSM density profile as a harbinger of core collapse

We present extensive multifrequency Karl G. Jansky Very Large Array (VLA) and Very Long Baseline Array (VLBA) observations of the radio-bright supernova (SN) IIb SN 2004C that span ∼40–2793 days post-explosion. We interpret the temporal evolution of the radio spectral energy distribution in the context of synchrotron self-absorbed emission from the explosion's forward shock as it expands in the circumstellar medium (CSM) previously sculpted by the mass-loss history of the stellar progenitor. VLBA observations and modeling of the VLA data point to a blastwave with average velocity ∼0.06 c that carries an energy of ≈1049 erg. Our modeling further reveals a flat CSM density profile ρCSM ∝ R−0.03±0.22 up to a break radius Rbr ≈ (1.96 ± 0.10) × 1016 cm, with a steep density gradient following ρCSM ∝ R−2.3±0.5 at larger radii. We infer that the flat part of the density profile corresponds to a CSM shell with mass ∼0.021 M☉, and that the progenitor's effective mass-loss rate varied with time over the range (50–500) × 10−5 M☉ yr−1 for an adopted wind velocity vw = 1000 km s−1 and shock microphysical parameters epsilone = 0.1, epsilonB = 0.01. These results add to the mounting observational evidence for departures from the traditional single-wind mass-loss scenarios in evolved, massive stars in the centuries leading up to core collapse. Potentially viable scenarios include mass loss powered by gravity waves and/or interaction with a binary companion

Obesity surgery and risk of colorectal and other obesity-related cancers: An English population-based cohort study

Background: The association between obesity surgery (OS) and cancer risk remains unclear. We investigated this association across the English National Health Service. A population-based Swedish study has previously suggested that OS may increase the risk of developing colorectal cancer (CRC). Methods: A retrospective observational study of individuals who underwent OS (surgery cohort) or diagnosed with obesity, but had no OS (no-surgery cohort) (1997–2013) were identified using Hospital Episode Statistics. Subsequent diagnosis of CRC, breast, endometrial, kidney and lung cancer, as well as time ‘at risk’, were determined by linkage to National Cancer Registration & Analysis Service and Office of National Statistics data, respectively. Standardised incidence ratios (SIR) in relation to OS were calculated. Results: 1 002 607 obese patients were identified, of whom 3.9% (n = 39 747) underwent OS. In the no-surgery obese population, 3 237 developed CRC (SIR 1.12 [95% CI 1.08–1.16]). In those who underwent OS, 43 developed CRC (SIR 1.26 [95% CI 0.92–1.71]). The OS cohort demonstrated decreased breast cancer risk (SIR 0.76 [95% CI 0.62–0.92]), unlike the no surgery cohort (SIR 1.08 [95% CI 1.04–1.11]). Increased risk of endometrial and kidney cancer was observed in surgery and no-surgery cohorts. Conclusions: CRC risk is increased in individuals diagnosed as obese. Prior obesity surgery was not associated with an increased CRC risk. However, the OS population was small, with limited follow-up. Risk of breast cancer after OS is reduced compared with the obese no-surgery population, while the risk of endometrial and kidney cancers remained elevated after OS

Late relapse of diabetes after bariatric surgery: not rare, but not a failure

Objective: To characterize the status of cardiometabolic risk factors after late relapse of type 2 diabetes mellitus (T2DM) and to identify factors predicting relapse after initial diabetes remission following bariatric surgery to construct prediction models for clinical practice. Research design and methods: Outcomes of 736 patients with T2DM who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) at an academic center (2004–2012) and had ≥5 years’ glycemic follow-up were assessed. Of 736 patients, 425 (58%) experienced diabetes remission (HbA1c <6.5% [48 mmol/mol] with patients off medications) in the 1st year after surgery. These 425 patients were followed for a median of 8 years (range 5–14) to characterize late relapse of diabetes. Results: In 136 (32%) patients who experienced late relapse, a statistically significant improvement in glycemic control, number of diabetes medications including insulin use, blood pressure, and lipid profile was still observed at long-term. Independent baseline predictors of late relapse were preoperative number of diabetes medications, duration of T2DM before surgery, and SG versus RYGB. Furthermore, patients who relapsed lost less weight during the 1st year after surgery and regained more weight afterward. Prediction models were constructed and externally validated. Conclusions: While late relapse of T2DM is a real phenomenon (one-third of our cohort), it should not be considered a failure, as the trajectory of the disease and its related cardiometabolic risk factors is changed favorably after bariatric surgery. Earlier surgical intervention, RYGB (compared with SG) and more weight loss (less late weight regain) are associated with less diabetes relapse in the long-term

The Young Supernova Experiment: Survey Goals, Overview, and Operations

Time domain science has undergone a revolution over the past decade, with tens of thousands of new supernovae (SNe) discovered each year. However, several observational domains, including SNe within days or hours of explosion and faint, red transients, are just beginning to be explored. Here, we present the Young Supernova Experiment (YSE), a novel optical time-domain survey on the Pan-STARRS telescopes. Our survey is designed to obtain well-sampled $griz$ light curves for thousands of transient events up to $z \approx 0.2$. This large sample of transients with 4-band light curves will lay the foundation for the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope, providing a critical training set in similar filters and a well-calibrated low-redshift anchor of cosmologically useful SNe Ia to benefit dark energy science. As the name suggests, YSE complements and extends other ongoing time-domain surveys by discovering fast-rising SNe within a few hours to days of explosion. YSE is the only current four-band time-domain survey and is able to discover transients as faint $\sim$21.5 mag in $gri$ and $\sim$20.5 mag in $z$, depths that allow us to probe the earliest epochs of stellar explosions. YSE is currently observing approximately 750 square degrees of sky every three days and we plan to increase the area to 1500 square degrees in the near future. When operating at full capacity, survey simulations show that YSE will find $\sim$5000 new SNe per year and at least two SNe within three days of explosion per month. To date, YSE has discovered or observed 8.3% of the transient candidates reported to the International Astronomical Union in 2020. We present an overview of YSE, including science goals, survey characteristics and a summary of our transient discoveries to date.Comment: ApJ, in press; more information at https://yse.ucsc.edu

SN 2023ixf in Messier 101: Photo-ionization of Dense, Close-in Circumstellar Material in a Nearby Type II Supernova

We present UV/optical observations and models of supernova (SN) 2023ixf, a type II SN located in Messier 101 at 6.9 Mpc. Early-time ("flash") spectroscopy of SN 2023ixf, obtained primarily at Lick Observatory, reveals emission lines of H I, He I/II, C IV, and N III/IV/V with a narrow core and broad, symmetric wings arising from the photo-ionization of dense, close-in circumstellar material (CSM) located around the progenitor star prior to shock breakout. These electron-scattering broadened line profiles persist for $\sim$8 days with respect to first light, at which time Doppler broadened features from the fastest SN ejecta form, suggesting a reduction in CSM density at $r \gtrsim 10^{15}$ cm. The early-time light curve of SN2023ixf shows peak absolute magnitudes (e.g., $M_{u} = -18.6$ mag, $M_{g} = -18.4$ mag) that are $\gtrsim 2$ mag brighter than typical type II supernovae, this photometric boost also being consistent with the shock power supplied from CSM interaction. Comparison of SN 2023ixf to a grid of light curve and multi-epoch spectral models from the non-LTE radiative transfer code CMFGEN and the radiation-hydrodynamics code HERACLES suggests dense, solar-metallicity, CSM confined to $r = (0.5-1) \times 10^{15}$ cm and a progenitor mass-loss rate of $\dot{M} = 10^{-2}$ M$_{\odot}$yr$^{-1}$. For the assumed progenitor wind velocity of $v_w = 50$ km s$^{-1}$, this corresponds to enhanced mass-loss (i.e., ``super-wind'' phase) during the last $\sim$3-6 years before explosion.Comment: 18 pages, 8 figures. Submitted to ApJ