222 research outputs found

    Integrated Direct Air Capture and Oxidative Dehydrogenation of Propane with CO2 at Isothermal Conditions

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    Developing routes of utilizing CO2 emissions is important for long-term environmental preservation, as storing such emissions underground will eventually become unsustainable. One way of utilizing CO2 emissions is as a light-oxidant feedstock for oxidative dehydrogenation of propane (ODHP) to propylene. However, the adsorption and reaction steps typically occur at widely different temperatures, meaning that the thermal gradients – and by extension process energy requirements – are often unreasonably high. In recent years, dual-functional materials (DFMs) – i.e., materials comprised of a high temperature adsorbent phase alongside a heterogeneous catalyst – have been employed for combined CO2 adsorption and utilization over one material within a single bed using a reduced thermal gradient. However, these materials have never been formed into practical contactors and have never been applied to ODHP applications. Therefore, in this study we manufactured the first-generation of DFM adsorbent/catalyst monoliths, comprised of CaO (adsorbent) and M@ZSM-5 (M = V-, Ga-, Ti-, or Ni-oxide) heterogeneous catalysts, using our novel direct metal-oxide 3D printing technique. The monoliths were vigorously characterized using N2 physisorption, C3H8-DRIFTS, NH3-TPD, Py-FTIR, H2-TPR, XRD, XPS, and elemental mapping and were assessed for CO2 capture/ODHP utilization at 600–700 ºC. The adsorption/catalysis experiments revealed that these materials can perform both processes effectively at 600 ºC, with reduced propylene yield at higher temperature, which eliminated the need for a thermal gradient between the adsorption and catalysis steps. Between the various samples, the Ti-doped monolith generated the best balance of CO2 conversion (76%) and propylene selectivity (39%), due to the high dispersion of TiO2, favorable redox properties and controlled acidity of the dopant. However, it was also found that varying the metal dopant could be used to control the heuristics of CO2/C3H8 conversion, C3H6 selectivity, and C3H6 yield, meaning that the manufacturing process outlined herein represents a promising way of tuning the chemical properties of structured DFM adsorbent/catalyst materials. More importantly, this study establishes a promising proof-of-concept for 3D printing as a facile means of structuring these exciting composite materials and expands DFMs to the previously unexplored application of ODHP

    Novel Cemented Technique for Trochanteric Fixation and Reconstruction of the Abductor Mechanism in Proximal and Total Femoral Arthroplasty: An Observational Study

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    Background: Little evidence exists regarding the clinical outcomes of cemented trochanteric fixation for abductor mechanism reconstruction in proximal or total femoral replacements. Clinical outcomes were assessed for a novel cemented technique for trochanteric fixation in femoral megaprostheses. Methods: A descriptive series of 13 patients who underwent proximal or total femoral arthroplasty from 2016 to 2019 were reviewed. Radiographic trochanteric displacement \u3e 1 cm defined construct failure. A Kaplan-Meier survival analysis was performed to determine survival rates for these cemented constructs. Demographic information was obtained to better characterize the patient population in whom this technique was used. Results: Eleven patients were included (age = 63.6 years; 45.4% females; body mass index = 31.7). Mean time to final radiographic follow-up was 73.8 weeks. Three of 11 (27.2%) patients had construct failure. Overall, survival at 1 year was 81.8%. At 2 years, survival of cemented constructs was 65.5%. More construct failures occurred in patients who sustained a postoperative dislocation than in those who did not (P = .05). Conclusions: This novel cemented trochanteric fixation technique for reconstruction of the abductor mechanism in femoral megaprostheses had 81.8% survival at 1 year postoperatively. While longitudinal comparative studies with larger samples are needed, the cemented technique may provide a viable alternative to traditional cementless methods of trochanteric fixation. Increased construct failure rates after postoperative dislocation highlight the importance of robust abductor reconstruction in these implants

    Development of the Infant Gut Microbiome Predicts Temperament Across the First Year of Life

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    Perturbations to the gut microbiome are implicated in altered neurodevelopmental trajectories that may shape life span risk for emotion dysregulation and affective disorders. However, the sensitive periods during which the microbiome may influence neurodevelopment remain understudied. We investigated relationships between gut microbiome composition across infancy and temperament at 12 months of age. In 67 infants, we examined if gut microbiome composition assessed at 1–3 weeks, 2, 6, and 12 months of age was associated with temperament at age 12 months. Stool samples were sequenced using the 16S Illumina MiSeq platform. Temperament was assessed using the Infant Behavior Questionnaire-Revised (IBQ-R). Beta diversity at age 1–3 weeks was associated with surgency/extraversion at age 12 months. Bifidobacterium and Lachnospiraceae abundance at 1–3 weeks of age was positively associated with surgency/extraversion at age 12 months. Klebsiella abundance at 1–3 weeks was negatively associated with surgency/extraversion at 12 months. Concurrent composition was associated with negative affectivity at 12 months, including a positive association with Ruminococcus-1 and a negative association with Lactobacillus. Our findings support a relationship between gut microbiome composition and infant temperament. While exploratory due to the small sample size, these results point to early and late infancy as sensitive periods during which the gut microbiome may exert effects on neurodevelopment

    Contact with Caregivers is Associated with Composition of the Infant Gastrointestinal Microbiome in the First 6 Months of Life

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    Objectives Little is known about how physical contact at birth and early caregiving environments influence the colonization of the infant gastrointestinal microbiome. We investigated how infant contact with caregivers at birth and within the first 2 weeks of life relates to the composition of the gastrointestinal microbiome in a sample of U.S. infants (n = 60). Methods Skin-to-skin and physical contact with caregivers at birth and early caregiving environments were surveyed at 2 weeks postpartum. Stool samples were collected from infants at 2 weeks, 2, 6, and 12 months of age and underwent 16S rRNA sequencing as a proxy for the gastrointestinal microbiome. Associations between early caregiving environments and alpha and beta diversity, and differential abundance of bacteria at the genus level were assessed using PERMANOVA, and negative binomial mixed models in DEseq2. Results Time in physical contact with caregivers explained 10% of variation in beta diversity at 2 weeks\u27 age. The number of caregivers in the first few weeks of life explained 9% of variation in beta diversity at 2 weeks and the number of individuals in physical contact at birth explained 11% of variation in beta diversity at 6 months. Skin-to-skin contact on the day of birth was positively associated with the abundance of eight genera. Infants held for by more individuals had greater abundance of eight genera. Discussion Results reveal a potential mechanism (skin-to-skin and physical contact) by which caregivers influence the infant gastrointestinal microbiome. Our findings contribute to work exploring the social transmission of microbes

    Kepler Eclipsing Binary Stars. VI. Identification of Eclipsing Binaries in the K2 Campaign 0 Data-set

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    The original {\it Kepler} mission observed and characterized over 2400 eclipsing binaries in addition to its prolific exoplanet detections. Despite the mechanical malfunction and subsequent non-recovery of two reaction wheels used to stabilize the instrument, the {\it Kepler} satellite continues collecting data in its repurposed {\it K2} mission surveying a series of fields along the ecliptic plane. Here we present an analysis of the first full baseline {\it K2} data release: the Campaign 0 data-set. In the 7761 light curves, we have identified a total of 207 eclipsing binaries. Of these, 97 are new discoveries that were not previously identified. Our pixel-level analysis of these objects has also resulted in identification of several false positives (observed targets contaminated by neighboring eclipsing binaries), as well as the serendipitous discovery of two short period exoplanet candidates. We provide catalog cross-matched source identifications, orbital periods, morphologies and ephemerides for these eclipsing systems. We also describe the incorporation of the K2 sample into the Kepler Eclipsing Binary Catalog\footnote{\url{keplerebs.villanova.edu/k2}}, present spectroscopic follow-up observations for a limited selection of nine systems, and discuss prospects for upcoming {\it K2} campaigns.Comment: Accepted for publication in MNRAS. 51 pages [20 figures, 8 tables]. Results available online in the Kepler Eclipsing Binary Star Catalog http://keplerebs.villanova.edu/k

    Principles of Stakes Fairness in Sport

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    Fairness in sport is not just about assigning the top prizes to the worthiest competitors. It is also about the way the prize structure itself is organised. For many sporting competitions, although it may be acceptable for winners to receive more than losers, it can seem unfair for winners to take everything and for losers to get nothing. Yet this insight leaves unanswered some difficult questions about what stakes fairness requires and which principles of stakes fairness are appropriate for particular competitions. In this article I specify a range of different principles of stakes fairness (ten in total) that could regulate sporting competitions. I also put forward a theoretical method for pairing up appropriate principles of stakes fairness with given sporting competitions. Specifically, I argue that the underlying rationales for holding sporting competitions can provide useful guides for identifying appropriate principles of stakes fairness. I then seek to clarify and work through some of the implications of this method for a sample of real world controversies over sporting prize structures. I also attempt to refine the method in response to two possible objections from indeterminacy and relativism. Finally, I compare and contrast my conclusions with more general philosophical debates about justice

    The Open Source GAITOR Suite for Rodent Gait Analysis

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    Locomotive changes are often associated with disease or injury, and these changes can be quantified through gait analysis. Gait analysis has been applied to preclinical studies, providing quantitative behavioural assessment with a reasonable clinical analogue. However, available gait analysis technology for small animals is somewhat limited. Furthermore, technological and analytical challenges can limit the effectiveness of preclinical gait analysis. The Gait Analysis Instrumentation and Technology Optimized for Rodents (GAITOR) Suite is designed to increase the accessibility of preclinical gait analysis to researchers, facilitating hardware and software customization for broad applications. Here, the GAITOR Suite’s utility is demonstrated in 4 models: a monoiodoacetate (MIA) injection model of joint pain, a sciatic nerve injury model, an elbow joint contracture model, and a spinal cord injury model. The GAITOR Suite identified unique compensatory gait patterns in each model, demonstrating the software’s utility for detecting gait changes in rodent models of highly disparate injuries and diseases. Robust gait analysis may improve preclinical model selection, disease sequelae assessment, and evaluation of potential therapeutics

    Kepler eclipsing binary stars. VII. the catalogue of eclipsing binaries found in the entire Kepler data set

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    The primary Kepler Mission provided nearly continuous monitoring of ~200,000 objects with unprecedented photometric precision. We present the final catalog of eclipsing binary systems within the 105 deg2 Kepler field of view. This release incorporates the full extent of the data from the primary mission (Q0-Q17 Data Release). As a result, new systems have been added, additional false positives have been removed, ephemerides and principal parameters have been recomputed, classifications have been revised to rely on analytical models, and eclipse timing variations have been computed for each system. We identify several classes of systems including those that exhibit tertiary eclipse events, systems that show clear evidence of additional bodies, heartbeat systems, systems with changing eclipse depths, and systems exhibiting only one eclipse event over the duration of the mission. We have updated the period and galactic latitude distribution diagrams and included a catalog completeness evaluation. The total number of identified eclipsing and ellipsoidal binary systems in the Kepler field of view has increased to 2878, 1.3% of all observed Kepler targets

    Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa

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    There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5-6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, 'place provisioning', longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.Social Science and Humanities Research Council of Canada; NORAM; American-Scandinavian Foundation; Fundacao para a Ciencia e Tecnologia [SFRH/BPD/73598/2010]; IGERT [DGE 0801634]; Hyde Family Foundations; Institute of Human Origins; National Science Foundation [BCS-9912465, BCS-0130713, BCS-0524087, BCS-1138073]; John Templeton Foundation to the Institute of Human Origins at Arizona State Universit
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