10,000 publications from this institution
Reactive carbon capture (RCC) is a promising solution for carbon capture and utilization. RCC involves CO2 capture, typically with amine solutions to form carbamate, followed by immediate conversion into value-added chemicals and fuels, typically via electrochemical means. RCC may enhance CO2 reduction (CO2R) by overcoming the inherent limiting low solubility of CO2 in aqueous solutions. In this work, we present a systematic study of the influence of monoethanolamine (MEA) on CO2R performance over an Ag cathode in KHCO3 electrolytes. Contrary to prior work, the study finds no evidence for the direct reduction of carbamate anions. Instead, the presence of MEA suppresses the rate of CO formation while increasing that of H2. These results are supported by a boundary-layer continuum model of mass transport and reaction that correctly predicts experimental trends and demonstrates that MEA reduces the concentration of CO2 near the cathode. Thus, alternative strategies are necessary to achieve RCC in aqueous environments.
The COVID-19 pandemic increased remote working, online shopping, and telehealth, with important differences across socioeconomic groups in their ability to use such new technologies. Orkun Saka, Barry Eichengreen, and Cevat Giray Aksoy investigate past epidemics and find that they significantly increase the likelihood that individuals do their banking using the internet, mobile banks, and automated teller machines (ATMs). But inequality plays a role. Individuals who already have internet coverage are more likely to shift toward online banking during an epidemic.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
We present 84 spectra of Type Ib/c and Type IIb supernovae (SNe), describing the individual SNe in detail. The relative depths of the helium absorption lines in the spectra of the SNe Ib appear to provide a measurement of the temporal evolution of the SN, with He I 5876 and He I 7065 growing in strength relative to He I 6678 over time. Light curves for three of the SNe Ib provide a sequence for correlating the helium-line strengths. We find that some SNe Ic show evidence for weak helium absorption, but most do not. Aside from the presence or absence of the helium lines, there are other spectroscopic differences between SNe Ib and SNe Ic. On average, the O I 7774 line is stronger in SNe Ic than in SNe Ib. In addition, the SNe Ic have distinctly broader emission lines at late times, indicating either a consistently larger explosion energy and/or lower envelope mass for SNe Ic than for SNe Ib. While SNe Ib appear to be basically homogeneous, the SNe Ic are quite heterogeneous in their spectroscopic characteristics. Three SNe Ic that may have been associated with gamma-ray bursts are also discussed; two of these have clearly peculiar spectra, while the third seems fairly typical.
Cytotoxic T lymphocytes (CTL) can recognize antigenic peptides bound in a groove formed by the alpha 1 and alpha 2 domains of the heterodimeric major histocompatibility complex class I molecule. Proper assembly, transport, and stability of functional class I molecules is thought to require beta 2 microglobulin (beta 2m), the light chain of the class I heterodimer. We show here that the requirement for beta 2m is not absolute. beta 2m- cells can be stained by the Db alpha 1 domain-specific B22-249.1 monoclonal antibody, which detects a conformation-dependent epitope. Furthermore, beta 2m- Con A blast target cells can be lysed by alloreactive CTL, even in serum-free conditions. Contrary to previous reports, the expression of low levels of conformed Db heavy (H) chains is a property to both normal and transformed beta 2m- cells. Finally, we present evidence that a subset of properly conformed H chains, free of beta 2m, may have almost equal representation on beta 2m+ and beta 2m- cells.
Abstract Objective Building on the original taxonomy of hospital‐based health systems from 20 years ago, we develop a new taxonomy to inform emerging public policy and practice developments. Data Sources The 2016 American Hospital Association's (AHA) Annual Survey; the 2016 IQVIA Healthcare Organizations and Systems (HCOS) database; and the 2017‐2018 National Survey of Healthcare Organizations and Systems (NSHOS). Study Design Cluster analysis of the 2016 AHA Annual Survey data to derive measures of differentiation, centralization, and integration to create categories or types of hospital‐based health systems. Data Collection Principal components factor analysis with varimax rotation generating the factors used in the cluster algorithms. Principal Findings Among the four cluster types, 54% (N = 202) of systems are decentralized (−0.35) and relatively less differentiated (−0.37); 23% of systems (N = 85) are highly differentiated (1.28) but relatively decentralized (−0.29); 15% (N = 57) are highly centralized (2.04) and highly differentiated (0.65); and approximately 9 percent (N = 33) are least differentiated (−1.35) and most decentralized (−0.64). Despite differences in calculation, the Highly Centralized, Highly Differentiated System Cluster and the Undifferentiated, Decentralized System Cluster were similar to those identified 20 years ago. The other two system clusters contained similarities as well as differences from those 20 years ago. Overall, 82 percent of the systems remain relatively decentralized suggesting they operate largely as holding companies allowing autonomy to individual hospitals operating within the system. Conclusions The new taxonomy of hospital‐based health systems bears similarities as well as differences from 20 years ago. Important applications of the taxonomy for addressing current challenges facing the healthcare system, such as the transition to value‐based payment models, continued consolidation, and the growing importance of the social determinants of health, are highlighted.
Reduced sleep duration is associated with HOMA-IR in adolescence. Long sleep duration is not associated. Interventions to extend sleep duration may reduce diabetes risk in youth.
Abstract Hydrosilierungsreaktionen repräsentieren eine wichtige Klasse von chemischen Umwandlungen, und somit besteht ein erhebliches Interesse, den Umfang dieser Reaktionen durch die Entwicklung neuer Katalysatoren zu erweitern. Ein Hauptanliegen, das aus diesen Untersuchungen erwächst, ist die Entwicklung von Katalysatoren mit elektrophilem Charakter, die mittels Si‐H‐Aktivierung die Elektrophilie auf Silicium übertragen. Dieser Mechanismustyp wurde für Katalysatoren vorgeschlagen, die sich von den Übergangsmetallen der 4. Gruppe bis hin zu Hauptgruppenelementverbindungen der 15. Gruppe erstrecken. Zudem sind andere elektrophile Siliciumspezies wie Silylenkomplexe und η 3 ‐H 2 SiRR′‐Komplexe als Intermediate in Hydrosilierungsreaktionen identifiziert worden. In diesem Aufsatz werden unterschiedliche Typen von Katalysatoren verglichen, um die enorme Breite an Hydrosilierungsmechanismen aufzuzeigen, die über elektrophile Siliciumzentren verlaufen. Die Bedeutung dieser Katalysatoren für die Entwicklung neuer Hydrosilierungsreaktionen wird diskutiert.
Mapping sidewalks in urban environments is key in the creation of pedestrian-friendly, sustainable cities. Currently, urban planners are hindered by a lack of information available in a format suitable for the large-scale analysis of sidewalk design. To demonstrate the impact that information technology could have in this area, we leverage techniques from machine learning and computer vision to gather information about the presence and quality of sidewalks in map images. In particular, we identify sidewalk segments in street view images using a random forest classifier, utilizing a set of local and global features that include geometric context, presence of lanes, pixel color, and location. Our results illustrate that this approach is effective in classifying sidewalk segments in a large set of street view images. This algorithm can be easily extended to other datasets, and can be automated to gather complete, fine-grained details about sidewalks for arbitrarily large urban environments.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
