The Chemistry and Kinetics of Polyethylene Pyrolysis: A Process to Produce Fuels and Chemicals.

The annual global production of plastics reached 335 million metric tons in 2016. Most waste plastics are landfilled or enter the natural environment in an uncontrolled manner. Pyrolysis can convert waste plastics, such as polyethylene (PE), to smaller hydrocarbons that can be used as fuels or chemicals. In this work, pyrolysis of PE was studied by thermogravimetric analysis (TGA) and in a fluidized-bed reactor. A kinetic model based on two parallel first-order random-scission steps was developed on the basis of the TGA results. PE was pyrolyzed in a fluidized-bed reactor over the temperature range of 500-600 °C and at residence times of 12.4-20.4 s. The yield of gas-phase products increased from 8.2 to 56.8 wt %, and the yield of liquid-phase products decreased from 81.2 to 28.5 wt % as the temperature increased from 500 to 600 °C. Detailed analysis of the gas- and liquid-phase products revealed their potential as precursors for production of fuels and chemicals. Gas-phase products included hydrogen, C1 -C4 paraffins, C2 -C4 olefins, and 1,3-butadiene. The major liquid-phase products were mono-olefins and cycloalkanes/alkadienes with smaller amounts of n-paraffins, isoparaffins, and aromatics. The carbon-number distribution of the fluidized-bed pyrolysis products suggested contributions of nonrandom reactions of random-scission fragments at low conversion.

Detection of CuAuPd Phase Boundaries Using Core Level Shifts.

A high throughput study has been conducted of the Cu 2p3/2, Au 4f7/2, and Pd 3d3/2 X-ray photoemission spectra obtained from a continuous distribution of CuxAuyPd1-x-y alloy samples prepared as a single composition spread alloy film (CSAF). All three elements exhibit shifts of their core level binding energies with respect to their pure states when diluted into the alloy. The Cu 2p3/2 core level shift (CLS) exhibits additional shifts over the composition ranges at which the CuxAuyPd1-x-y alloy transitions between FCC and B2 phases. This discontinuous CLS has been used to map the extent of the B2 phase across the ternary CuxAuyPd1-x-y alloy composition space. The sensitivity of core level binding energies to the alloy phase offers an opportunity to use XPS to study phases in alloy nanoparticles, ultrathin films, and other morphologies that are not amenable to structure determination by diffraction based methods.

Novel indole-based compounds that differentiate alkylindole-sensitive receptors from cannabinoid receptors and microtubules: Characterization of their activity on glioma cell migration.

Indole-based compounds, such as the alkyl-indole (AI) compound WIN55212-2, activate the cannabinoid receptors, CB1 and CB2, two well-characterized G protein-coupled receptors (GPCR). Reports indicate that several indole-based cannabinoid agonists, including WIN55212-2, lack selectivity and interact with at least two additional targets: AI-sensitive GPCRs and microtubules. Studying how indole-based compounds modulate the activity of these 4 targets has been difficult as selective chemical tools were not available. Here we report the pharmacological characterization of six newly-developed indole-based compounds (ST-11, ST-23, ST-25, ST-29, ST-47 and ST-48) that exhibit distinct binding affinities at AI-sensitive receptors, cannabinoid CB1 and CB2 receptors and the colchicine site of tubulin. Several compounds exhibit some level of selectivity for AI-sensitive receptors, including ST-11 that binds AI-sensitive receptors with a Kd of 52nM and appears to have a weaker affinity for the colchicine site of tubulin (Kd=3.2µM) and does not bind CB1/CB2 receptors. Leveraging these characteristics, we show that activation of AI-sensitive receptors with ST-11 inhibits both the basal and stimulated migration of the Delayed Brain Tumor (DBT) mouse glioma cell line. Our study describes a new series of indole-based compounds that enable the pharmacological and functional differentiation of alkylindole-sensitive receptors from cannabinoid receptors and microtubules.

High-Throughput Screening Across Quaternary Alloy Composition Space: Oxidation of (AlxFeyNi1-x-y)∼0.8Cr∼0.2.

Composition spread alloy films (CSAFs) are commonly used as libraries for high-throughput screening of composition-property relationships in multicomponent materials science. Because lateral gradients afford two degrees of freedom, an n-component CSAF can, in principle, contain any composition range falling on a continuous two-dimensional surface through an (n - 1)-dimensional composition space. However, depending on the complexity of the CSAF gradients, characterizing and graphically representing this composition range may not be straightforward when n ≥ 4. The standard approach for combinatorial studies performed using quaternary or higher-order CSAFs has been to use fixed stoichiometric ratios of one or more components to force the composition range to fall on some well-defined plane in the composition space. In this work, we explore the synthesis of quaternary Al-Fe-Ni-Cr CSAFs with a rotatable shadow mask CSAF deposition tool, in which none of the component ratios are fixed. On the basis of the unique gradient geometry produced by the tool, we show that the continuous quaternary composition range of the CSAF can be rigorously represented using a set of two-dimensional "pseudoternary" composition diagrams. We then perform a case study of (AlxFeyNi1-x-y)∼0.8Cr∼0.2 oxidation in dry air at 427 °C to demonstrate how such CSAFs can be used to screen an alloy property across a continuous two-dimensional subspace of a quaternary composition space. We identify a continuous boundary through the (AlxFeyNi1-x-y)∼0.8Cr∼0.2 subspace at which the oxygen uptake into the CSAF between 1 and 16 h oxidation time increases abruptly with decreasing Al content. The results are compared to a previous study of the oxidation of AlxFeyNi1-x-y CSAFs in dry air at 427 °C.

Assessment of a High-Throughput Methodology for the Study of Alloy Oxidation using AlxFeyNi1-x-y Composition Gradient Thin Films.

The high-temperature oxidation of multicomponent metal alloys exhibits complex dependencies on composition, which are not fully understood for many systems. Combinatorial screening of the oxidation of many different compositions of a given alloy offers an ideal means for gaining fundamental insights into such systems. We have previously developed a high-throughput methodology for studying AlxFeyNi1-x-y alloy oxidation using ∼100 nm thick composition spread alloy films (CSAFs). In this work, we critically assess two aspects of this methodology: the sensitivity of CSAF oxidation behavior to variations in AlxFeyNi1-x-y composition and the differences between the oxidation behavior of ∼100 nm thick CSAFs and that of bulk AlxFeyNi1-x-y alloys. This was done by focusing specifically on AlxFe1-x and AlxNi1-x oxidation in dry air at 427 °C. Transitions between phenomenologically distinguishable types of oxidation behavior are found to occur over CSAF compositional ranges of <2 at. %. The oxidation of AlxFe1-x CSAFs is found to be very similar to that of bulk AlxFe1-x alloys, but some minor differences between CSAF and bulk behavior are observed for AlxNi1-x oxidation. On the basis of our assessment, high-throughput studies of CSAF oxidation appear to be an effective method for gaining fundamental insights into the composition dependence of the oxidation of bulk alloys.

Haunted by the ghost in the machine. Commentary on "The spirituality of human consciousness: a Catholic evaluation of some current neuro-scientific interpretations".

Metaphysical and epistemological dualism informs much contemporary discussion of the relationships of science and religion, in particular in relation to the neurosciences and the religious understanding of the human person. This dualism is a foundational artifact of modern culture; however, contemporary scientific research and historical theological scholarship encourage a more holistic view wherein human personhood is most fittingly understood as an emergent phenomenon of, but not simply reducible to, evolutionary and developmental neurobiology.

Building a cardiology practice.

This study was designed to quantify the clinical and marketing effectiveness of the Pocket EKG Clinical Based Marketing Program by measuring its impact on new patient visits, patient satisfaction, payor negotiations, and patient management at Pikes Peak Cardiology (PPC), Colorado Springs, Colorado. New patient visits were found to increase by 22% for 6.5 consecutive years. Ninety-two percent of patients surveyed found that the Pocket EKG Card promoted loyalty to the cardiology practice. The Pocket EKG Patient Satisfaction Survey was proven to satisfy Health Plan Employer Data and Information Set (HEDIS) guidelines as required in payor contracting. Finally, access to a baseline electrocardiogram contributed to a 54% reduction in unnecessary hospitalization. The Pocket EKG Clinical Based Marketing Program proved to successfully market PPC to its three customers: patients, payors, and primary care physicians.