We have performed a search over 3440 deg 2 of Epoch 1 (2017-2019) of the Very Large Array Sky Survey to identify unobscured quasars in the optical (0.2<z<3.2) and obscured active galactic nuclei (AGNs) in the infrared that have brightened dramatically in the radio over the past one to two decades. These sources would have been previously classified as "radio-quiet" quasars based on upper limits from the Faint Images of the Radio Sky at Twenty cm survey (1993-2011), but they are now consistent with "radio-loud" quasars ( -= -L 10 erg s 3 GHz 40 42 1). A quasi-simultaneous, multiband (∼1-18 GHz) follow-up study of 14 sources with the VLA has revealed compact sources (<0 1 or <1 kpc) with peaked radio spectral shapes. The highamplitude variability over decadal timescales at 1.5 GHz (100% to >2500%) but roughly steady fluxes over a few months at 3 GHz are inconsistent with extrinsic variability due to propagation effects, thus favoring an intrinsic origin. We conclude that our sources are powerful quasars hosting compact/young jets. This challenges the generally accepted idea that "radio-loudness" is a property of the quasar/AGN population that remains fixed on human timescales. Our study suggests that frequent episodes of short-lived AGN jets that do not necessarily grow to large scales may be common at high redshift. We speculate that intermittent but powerful jets on subgalactic scales could interact with the interstellar medium, possibly driving feedback capable of influencing galaxy evolution.

Context.— Immune checkpoint inhibitors (CPIs), including cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) inhibitors and the programmed death receptor-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors, are being increasingly used for treating many advanced malignancies. However, CPI therapy is also associated with gastrointestinal and hepatobiliary adverse effects. Objectives.— To review the adverse effects of CPI therapy on the gastrointestinal tract and hepatobiliary system. To describe histopathologic patterns and discuss differential diagnostic considerations in the diagnosis of CPI injuries. Data Sources.— Published peer-reviewed literature in the English language and personal experience in the diagnosis of CPI injuries. Conclusions.— The pathologic manifestations of CPI therapy–induced gastrointestinal and hepatobiliary injury are broad. The patterns of esophageal CPI injury include lymphocytic inflammation and ulcerative esophagitis, while those of gastric injury include chronic active gastritis, lymphocytic gastritis, focal enhancing gastritis, and periglandular inflammation. The duodenal injury may present as duodenitis with villous blunting and granulomas. We also noticed active colitis, microscopic colitis, chronic active colitis, increased apoptosis, ischemic colitis, and nonspecific inflammatory reactive changes in colonic injuries. The reported histologic features of hepatobiliary injuries are panlobular hepatitis, centrilobular necrosis, portal inflammation with bile duct injury, steatosis, nodular regenerative hyperplasia, and secondary sclerosing cholangitis. In summary, we here discuss the pathologic features and differential diagnosis of CPI therapy–induced gastrointestinal and hepatobiliary injury. Recognition of CPI injury is important to determine the proper management that often includes cessation of CPI therapy; and administration of steroids or other immunosuppressive agents, based on severity of injury.

Energetic feedback by Active Galactic Nuclei (AGNs) plays an important evolutionary role in the regulation of star formation (SF) on galactic scales. However, the effects of this feedback as a function of redshift and galaxy properties such as mass, environment and cold gas content remain poorly understood. The broad frequency coverage (1 to 116 GHz), high sensitivity (up to ten times higher than the Karl G. Jansky Very Large Array), and superb angular resolution (maximum baselines of at least a few hundred km) of the proposed next generation Very Large Array (ngVLA) are uniquely poised to revolutionize our understanding of AGNs and their role in galaxy evolution. Here, we provide an overview of the science related to AGN feedback that will be possible in the ngVLA era and present new continuum ngVLA imaging simulations of resolved radio jets spanning a wide range of intrinsic extents. We also consider key computational challenges and discuss exciting opportunities for multi-wavelength synergy with other next-generation instruments, such as the Square Kilometer Array and the James Webb Space Telescope. The unique combination of high-resolution, large collecting area, and wide frequency range will enable significant advancements in our understanding of the effects of jet-driven feedback on sub-galactic scales, particularly for sources with extents of a few pc to a few kpc such as young and/or lower-power radio AGNs, AGNs hosted by low-mass galaxies, radio jets that are interacting strongly with the interstellar medium of the host galaxy, and AGNs at high redshift.