Publications

Impairment of adipogenesis contributes to the development of obesity-related insulin resistance. The current in vitro approaches for its assessment represent crude estimates of the adipogenic potential because of the disruption of the in vivo microenvironment. A novel assessment of in vivo adipogenesis using the incorporation of the stable isotope deuterium (2H) into the DNA of isolated adipocytes and stroma-vascular fraction from adipose tissue has been developed. In the current study, we have refined this technique by purifying the adipocytes via a negative immune selection and sorting the plastic adherent stroma-vascular (aSV) subfraction (using 3 h culture) that contains mostly adipocyte progenitor cells and ∼10% of small adipocytes. Using a 3-week 8% 2H2O ingestion with a high-fat diet (HFD) or HFD plus pioglitazone (HFD-P), we demonstrate that the fractions of new aSV cells (faSV) and immunopurified adipocytes (fAD) (the ratio of their 2H-enrichment of DNA to the maximal 2H-enrichment of DNA of bone marrow reference cells) recapitulate the known hyperplastic mechanism of weight gain with pioglitazone treatment. We conclude that faSV and fAD are reliable indices of in vivo adipogenesis. The proposed method represents a valuable tool for studying the effect of interventions (drugs, diets, and exercise) on in vivo adipogenesis.

Reliable geochronological results gathered so far (n = 76) have considerably constrained the timing of the emplacement of the Karoo large igneous province (LIP). Yet strikingly missing from this dating effort is the huge southern sill complex cropping out in the >0.6 × 10 6 km 2 Main Karoo sedimentary basin. We present 16 new 40 Ar/ 39 Ar analyses carried out on fresh plagioclase and biotite separates from 15 sill samples collected along a N–S trend in the eastern part of the basin. The results show a large range of plateau and miniplateau ages (176.2 ± 1.3 to 183.8 ± 2.4 Ma), with most dates suggesting a ∼3 Ma (181–184 Ma) duration for the main sill events. The available age database allows correlation of the Karoo LIP emplacement with the Pliensbachian‐Toarcian second‐order biotic extinction, the global warming, and the Toarcian anoxic event (provided that adequate calibration between the 40 K and 238 U decay constant is made). The mass extinction and the isotopic excursions recorded at the base of the Toarcian appear to be synchronous with both the increase of magma emission of the Karoo LIP and the emplacement of the sills. The CO 2 and SO 2 derived from both volcanic emissions as well as carbon‐rich sedimentary layers intruded by sills might be the main culprits of the Pliensbachian‐Toarcian climate perturbations. We propose that the relatively low eruption rate of the Karoo LIP is one of the main reasons explaining why its impact on the biosphere is relatively low contrary to, e.g., the CAMP (Triassic‐Jurassic) and Siberia (Permo‐Triassic) LIPs.

Developing visual perception models for active agents and sensorimotor control are cumbersome to be done in the physical world, as existing algorithms are too slow to efficiently learn in real-time and robots are fragile and costly. This has given rise to learning-in-simulation which consequently casts a question on whether the results transfer to real-world. In this paper, we are concerned with the problem of developing real-world perception for active agents, propose Gibson Virtual Environment for this purpose, and showcase sample perceptual tasks learned therein. Gibson is based on virtualizing real spaces, rather than using artificially designed ones, and currently includes over 1400 floor spaces from 572 full buildings. The main characteristics of Gibson are: I. being from the real-world and reflecting its semantic complexity, II. having an internal synthesis mechanism, "Goggles", enabling deploying the trained models in real-world without needing further domain adaptation, III. embodiment of agents and making them subject to constraints of physics and space.

Abstract not Available.

Decarbonizing the chemicals industry requires net carbon negative technologies capable of displacing current greenhouse gas emitting processes. In particular, the generation of valuable monomers, such as butene, are currently produced by significant greenhouse gas emitting processes, including ethylene oligomerization and crude oil refining, which require high temperatures and pressures. Integrated, tandem solar fuels devices for the conversion of CO 2 to ethylene, using solar-driven CO 2 reduction (CO 2 R), combined with a photothermal reactor for ethylene oligomerization, offers a potential path to producing clean butene from CO 2 , using solar energy as the only driving force. A key challenge for the successful operation of a tandem photo-driven electrochemical-photothermal system is the co-design of the two processes, which are typically optimized under different operating conditions. Specifically, photo-driven electrochemical CO 2 R (pCO 2 R) reactors operate under ambient temperature and pressure conditions while thermally-driven ethylene oligomerization reactors prefer elevated temperatures (80-140 °C) and pressures (30-150 atm) to promote high activity as well as pure ethylene in the inlet stream. Operation of the tandem process under solar-driven conditions imposes additional constraints on the maximum power output of the pCO 2 R reactor and the maximum temperature which can be obtained in the photothermal reactor. Herein, we present an unassisted solar-driven tandem system coupling pCO 2 R with photothermal ethylene oligomerization for the conversion of CO 2 to butene in a single pass. This work presents a critical advancement in the development of solar fuels technologies for larger hydrocarbon generation and identifies the co-design principles which must be considered for implementation of tandem, solar-driven electrochemical-thermal processes.