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Abstract Internal signals from the body and external signals from the environment are processed by brain-wide circuits to guide behavior. However, the complete brain-wide circuit activity underlying interoception—the perception of bodily signals—and its interactions with sensorimotor circuits remain unclear due to technical barriers to accessing whole-brain activity at the cellular level during organ physiology perturbations. We developed an all-optical system for whole-brain neuronal imaging in behaving larval zebrafish during optical uncaging of gut-targeted nutrients and visuo-motor stimulation. Widespread neural activity throughout the brain encoded nutrient delivery, unfolding on multiple timescales across many specific peripheral and central regions. Evoked activity depended on delivery location and occurred with amino acids and D-glucose, but not L-glucose. Many gut-sensitive neurons also responded to swimming and visual stimuli, with brainstem areas primarily integrating gut and motor signals and midbrain regions integrating gut and visual signals. This platform links body-brain communication studies to brain-wide neural computation in awake, behaving vertebrates. 

Isoprene is one of the most common biogenic volatile organic compounds (BVOC) in the atmosphere, produced by many plants. Isoprene undergoes oxidation to form gaseous isoprene epoxydiols (IEPOX) under low-NOx conditions, which can lead to the formation of secondary organic aerosol (SOA) particles. SOA-containing particles affect climate by scattering and absorbing solar radiation or acting as cloud condensation nuclei (CCN). High concentrations of SOA are also associated with adverse health impacts in people. While in the atmosphere, IEPOX SOA particles continue to undergo reactions with atmospheric oxidants, including hydroxyl radical (OH). To isolate and probe this process, we studied atmospheric chemical processes in an aerosol chamber to better understand the evolution of heterogeneous OH oxidation of IEPOX-derived SOA particles. Since very little is understood about the structural and spectroscopic properties because of the complexity of their many sources and atmospheric processing, individual particle measurements are necessary to provide better understanding of the composition of IEPOX SOA. We injected particles composed of mixtures of ammonium sulfate and sulfuric acid across a range of acidities(PH = 0.5 – 2.5) and gas-phase IEPOX into the chamber to generate SOA. The SOA particles were then sent to an oxidation flow reactor, and exposed to different OH concentrations representative of aging of a number of days. We kept relative humidity (RH) constant at ~65%, the temperature was ~23 °C, and levels of oxidation were controlled by adjusting lamp intensity. After oxidized SOA was impacted on quartz substrates, we used single-particle Raman microspectroscopy to identify their functional group compositions. From the Raman vibrational spectra of submicron particles (~500-1000 nm aerodynamic diameter), we observed a distinct difference in core-shell morphology and composition: an organic outer layer and an aqueous-inorganic core. The core also has significantly more CH-stretch than the shell. Small changes were also observed with increasing oxidation, which are important to consider when predicting SOA particle evolution in the atmosphere. 

Isoprene has a strong effect on the oxidative capacity of the troposphere due to its abundance. Under low-NOx conditions, isoprene oxidizes to form isoprene-derived epoxydiols (IEPOX), contributing significantly to secondary organic aerosol (SOA) through heterogeneous reactions. In particular, organosulfates (OSs) can form from acid-driven reactive uptake of IEPOX onto preexisting particles followed by nucleophilic addition of inorganic sulfate, and they are an important component of SOA mass, primarily in submicron particles with long atmospheric lifetimes. Fundamental understanding of SOA and OS evolution in particles, including the formation of new compounds by oxidation as well as corresponding viscosity changes, is limited, particularly across relative humidity (RH) conditions above and below the deliquescence of typical sulfate aerosol particles. In a 2-m3 indoor chamber held at various RH values (30 – 80%), SOA was generated from reactive uptake of gas-phase IEPOX onto acidic ammonium sulfate aerosols (pH = 0.5 – 2.5) and then aged in an oxidation flow reactor (OFR) for 0 – 24 days of equivalent atmospheric ·OH exposure. We investigated the extent of inorganic sulfate conversion to organosulfate, formation of oligomers, single-particle physicochemical properties, such as viscosity and phase state, and oxidation kinetics. Chemical composition of particle-phase species, as well as aerosol morphological changes, are analyzed as a function of RH, oxidant exposure times, and particle acidity to better understand SOA and OS formation and destruction mechanisms in the ambient atmosphere. 

Abstract The manifestation of acute kidney injury (AKI) is associated with poor patient outcomes, with treatment options limited to hydration or renal replacement therapies. The onset of AKI is often associated with a surfeit of reactive oxygen species. Here, it is shown that selenium‐doped carbon quantum dots (SeCQDs) have broad‐spectrum antioxidant properties and prominent renal accumulation in both healthy and AKI mice. Due to these properties, SeCQDs treat or prevent two clinically relevant cases of AKI induced in murine models by either rhabdomyolysis or cisplatin using only 1 or 50 µg per mouse, respectively. The attenuation of AKI in both models is confirmed by blood serum measurements, kidney tissue staining, and relevant biomarkers. The therapeutic efficacy of SeCQDs exceeds amifostine, a drug approved by the Food and Drug Administration that also acts by scavenging free radicals. The findings indicate that SeCQDs show great potential as a treatment option for AKI and possibly other ROS‐related diseases.