Publications

Cyclic Voltammetry of Copper Metal in Lithium Hydroxide Solution at Elevated Temperatures

A cyclic voltammetric study of copper metal in is described. The results are consistent with the formation of both soluble and insoluble products at the metal surface. The formation and reduction of Cu(III) was found to occur near oxygen evolution at 25δC but not at the higher temperatures due to a sharp reduction in the oxygen evolution overpotential with temperature.

Iridium‐Catalyzed, Silyl‐Directed, <i>peri</i>‐Borylation of C−H Bonds in Fused Polycyclic Arenes and Heteroarenes

Abstract peri ‐Disubstituted naphthalenes exhibit interesting physical properties and unique chemical reactivity, due to the parallel arrangement of the bonds to the two peri ‐disposed substituents. Regioselective installation of a functional group at the position peri to 1‐substituted naphthalenes is challenging due to the steric interaction between the existing substituent and the position at which the second one would be installed. We report an iridium‐catalyzed borylation of the C−H bond peri to a silyl group in naphthalenes and analogous polyaromatic hydrocarbons. The reaction occurs under mild conditions with wide functional group tolerance. The silyl group and the boryl group in the resulting products are precursors to a range of functional groups bound to the naphthalene ring through C−C, C−O, C−N, C−Br and C−Cl bonds.

Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. I. A Reverberation‐based Measurement of the Black Hole Mass

A reverberation-mapping program on NGC 4395, the least luminous known Seyfert 1 galaxy, undertaken with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope yields a measurement of the mass of the central black hole M_BH = (3.6 ± 1.1) × 105 Msun. The observations consist of two visits of five orbits each, in 2004 April and July. During each of these visits, the UV continuum varied by at least 10% (rms), and only C IV λ1549 showed corresponding variations large enough to reliably determine the emission-line lag, which was measured to be of order 1 hr for both visits. The size of the C IV-emitting region is about a factor of 3 smaller than expected if the slope of the broad-line region radius-luminosity relationship is identical to that for the Hβ emission line. NGC 4395 is underluminous even for its small black hole mass; the Eddington ratio of ~1.2 × 10^-3 is lower than that of any other active galactic nucleus for which a black hole mass measurement has been made by emission-line reverberation

Microclimate-plant architectural interactions: Influence of leaf width on the mass and energy exchange of a soybean canopy☆

Carbon capture and conversion using metal–organic frameworks and MOF-based materials

This review summarizes recent advances and highlights the structure–property relationship on metal–organic framework-based materials for carbon dioxide capture and conversion.

Synthesis of precursors to ethylene glycol from formaldehyde and methyl formate catalyzed by heteropoly acids

Nonlinear-elastic fracture mechanics (NLEFM)

This chapter presents a concise description of nonlinear-elastic fracture mechanics, starting with Hutchinson, Rice, Rosengren (HRR) singularity and the definitions of the J-contour integral in terms of a characterizing parameter of the HRR crack-tip stress and displacement fields, a path-independent integral, and as a rate of change in potential energy per unit increase in crack area for a nonlinear-elastic solid. The use of J as a fracture criterion, together with J-solutions for various cracked geometries, is described as a basis for the measurement of the fracture toughness in the presence of plasticity; we provide further assessment of the crack growth toughness that can be quantified in terms of J-based resistance curves. Finally, we explain how modifications of the crack-tip fields in cracked configurations with lower constraint can be characterized in terms of the T-stress, and use this as a basis for a brief introduction to two-parameter characterizations of fracture.

Large kinetic asymmetry in the metal-insulator transition nucleated at localized and extended defects

Superheating and supercooling effects are characteristic kinetic processes in first-order phase transitions, and asymmetry between them is widely observed. In materials where electronic and structural degrees of freedom are coupled, a wide, asymmetric hysteresis may occur in the transition between electronic phases. Structural defects are known to seed heterogeneous nucleation of the phase transition, hence reduce the degree of superheating and supercooling. Here we show that in the metal-insulator transition of single-crystal VO${}_{2}$, a large kinetic asymmetry arises from the distinct spatial extension and distribution of two basic types of crystal defects: point defects and twin walls. Nanometer-thick twin walls are constantly consumed but regenerated during the transition to the metal phase, serving as dynamical heterogeneous nucleation seeds and eliminating superheating. On the other hand, the transition back to the insulator phase relies on nucleation at point defects because twinning is structurally forbidden in the metal phase, leading to a large supercooling. By controlling the formation, location, and extinction of these defects, the kinetics of the phase transition might be externally modulated, offering possible routes toward unique memory and logic device technologies.

GPU accelerated t-distributed stochastic neighbor embedding

ChemInform Abstract: Ammonia Synthesis Over Rhenium Single‐Crystal Catalysts. Kinetics, Structure Sensitivity, and Effect of Potassium and Oxygen.

Abstract The NH 3 synthesis over rhenium has been studied in the temp. range 720‐900 K using polycrystalline foils and four single‐crystal Re surfaces, Re(0001), (1O1O), (1120), and Re(1121).

Faculty Opinions recommendation of Identification of inhibitory components toxic toward zymomonas mobilis CP4(pZB5) xylose fermentation.

Thermal maps of gases in heterogeneous reactions

Supernovae 2002en, 2002eo, 2002es, and 2002eu

The Contribution of Hospitals and Health Care Systems to Community Health

This article reviews evidence on hospitals’ and health systems’ impacts on community health improvement. We begin with an overview of the history of community benefit and then discuss the lack of a widely accepted definition and measurement of community benefit activities as well as the expectations and accountability of tax-exempt not-for-profit hospitals and health systems in community initiatives. We highlight the approaches of two systems and identify strategic, cultural, technical, and structural challenges associated with increasing community benefit and health-improvement activities. We conclude by offering recommendations for policy and practice.

CCDC 717865: Experimental Crystal Structure Determination

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.

Productivity and Consumer Regulation—Concepts, Patterns, and Mechanisms

Reduced <i>in vivo</i> hepatic proteome replacement rates but not cell proliferation rates predict maximum lifespan extension in mice

Combating the social and economic consequences of a growing elderly population will require the identification of interventions that slow the development of age-related diseases. Preserved cellular homeostasis and delayed aging have been previously linked to reduced cell proliferation and protein synthesis rates. To determine whether changes in these processes may contribute to or predict delayed aging in mammals, we measured cell proliferation rates and the synthesis and replacement rates (RRs) of over a hundred hepatic proteins in vivo in three different mouse models of extended maximum lifespan (maxLS): Snell Dwarf, calorie-restricted (CR), and rapamycin (Rapa)-treated mice. Cell proliferation rates were not consistently reduced across the models. In contrast, reduced hepatic protein RRs (longer half-lives) were observed in all three models compared to controls. Intriguingly, the degree of mean hepatic protein RR reduction was significantly correlated with the degree of maxLS extension across the models and across different Rapa doses. Absolute rates of hepatic protein synthesis were reduced in Snell Dwarf and CR, but not Rapa-treated mice. Hepatic chaperone levels were unchanged or reduced and glutathione S-transferase synthesis was preserved or increased in all three models, suggesting a reduced demand for protein renewal, possibly due to reduced levels of unfolded or damaged proteins. These data demonstrate that maxLS extension in mammals is associated with improved hepatic proteome homeostasis, as reflected by a reduced demand for protein renewal, and that reduced hepatic protein RRs hold promise as an early biomarker and potential target for interventions that delay aging in mammals.

Elements of plasticity theory

Chapter 13 develops the modern theory for finite elastic-plastic deformations. It covers dissipation and highlights the role of the Eshelby tensor, and recovers the classical theory for isotropic materials using material symmetry arguments. Also developed are the equations of classical slip-line theory for plane-strain deformations.