29 research outputs found
Characterization of Biochars Produced From Peanut Hulls and Pine Wood with Different Pyrolysis Conditions
Background
Application of modern biomass pyrolysis methods for production of biofuels and biochar is potentially a significant approach to enable global carbon capture and sequestration. To realize this potential, it is essential to develop methods that produce biochar with the characteristics needed for effective soil amendment.
Methods
Biochar materials were produced from peanut hulls and pine wood with different pyrolysis conditions, then characterized by cation exchange (CEC) capacity assays, nitrogen adsorption–desorption isotherm measurements, micro/nanostructural imaging, infrared spectra and elemental analyses.
Results
Under a standard assay condition of pH 8.5, the CEC values of the peanut hull-derived biochar materials, ranging from 6.22 to 66.56 cmol kg−1, are significantly higher than those of the southern yellow pine-derived biochar, which are near zero or negative. The biochar produced from peanut hulls with a steam activation process yielded the highest CEC value of 66.56 cmol kg−1, which is about 5 times higher than the cation exchange capacity (12.51 cmol kg−1) of a reference soil sample. Notably, biochar produced from peanut hulls with batch barrel retort pyrolysis also has a much higher CEC value (60.12 cmol kg−1) than that (12.45 cmol kg−1) from Eprida’s H2-producing continuous steam injection process. The CEC values were shown to correlate well with the ratios of oxygen atoms to carbon atoms (O:C ratios) in the biochar materials. The higher O:C ratio in a biochar material may indicate the presence of more hydroxyl, carboxylate, and carbonyl groups that contribute to a higher CEC value for the biochar product. In addition, the increase in surface area can also play a role in increasing the CEC value of biochar, as in the case of the steam activation char.
Conclusion
Comparison of characterization results indicated that CEC value is determined not only by the type of the source biomass materials but also by the pyrolysis conditions. Biochar with the desirable characteristics of extremely high surface area (700 m2/g) and cation exchange capacity (\u3e 60 cmol kg) was created through steam activation
The Effects of Ceria Loading on Three-Way Catalysts for Passive SCR Operation
Passive SCR systems, which employ both a three-way catalyst and SCR catalyst, are effective for the reduction of nitrogen oxide (NOx) emissions from lean burn gasoline engines. However, questions remain regarding the effect of three-way catalyst formulations on their performance in these systems. Here, Pd/CeOx/Al2O3 catalysts with variable CeOx loading were synthesized, characterized, and evaluated to determine the effects of CeOx on catalyst performance. While a small amount of ceria was beneficial for promoting essential reactions, excess ceria was detrimental due to the increase in oxygen storage capacity. Additionally, insights into potential reaction pathways for NH3 production were determined
The Effects of Ceria Loading on Three-Way Catalysts for Passive SCR Operation
Passive SCR systems, which employ both a three-way catalyst and SCR catalyst, are effective for the reduction of nitrogen oxide (NOx) emissions from lean burn gasoline engines. However, questions remain regarding the effect of three-way catalyst formulations on their performance in these systems. Here, Pd/CeOx/Al2O3 catalysts with variable CeOx loading were synthesized, characterized, and evaluated to determine the effects of CeOx on catalyst performance. While a small amount of ceria was beneficial for promoting essential reactions, excess ceria was detrimental due to the increase in oxygen storage capacity. Additionally, insights into potential reaction pathways for NH3 production were determined
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A US perspective on closing the carbon cycle to defossilize difficult-to-electrify segments of our economy
Electrification to reduce or eliminate greenhouse gas emissions is essential to mitigate climate change. However, a substantial portion of our manufacturing and transportation infrastructure will be difficult to electrify and/or will continue to use carbon as a key component, including areas in aviation, heavy-duty and marine transportation, and the chemical industry. In this Roadmap, we explore how multidisciplinary approaches will enable us to close the carbon cycle and create a circular economy by defossilizing these difficult-to-electrify areas and those that will continue to need carbon. We discuss two approaches for this: developing carbon alternatives and improving our ability to reuse carbon, enabled by separations. Furthermore, we posit that co-design and use-driven fundamental science are essential to reach aggressive greenhouse gas reduction targets
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two
Background
The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd.
Methods
We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background.
Results
First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001).
Conclusions
In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
Fluorescent 1,8-Naphthalimide Dyes as Photochemical Sensors for the Detection of Transition Metal Ion Concentrations in Non-aqueous Solutions
Designing molecules that combine a fluorophore and receptor in a modular fashion is a growing field used for chemical sensing. The photoactive supramolecule Nbutyl- 4(2\u27 -aminoethyl)amino-1,8-naphthalimide is shown to be capable of considerable tuning to satisfy the requirements of a versatile sensing system. In this research it is shown that efficient through-space intramolecular photoinduced electron transfer (PET) between the fluorophore and amino group (used here as a receptor for the metals and protons) is responsible for the photoreactive signaling pathway. There exists an intramolecular charge transfer reaction leading from a locally excited (LE) state to a charge transfer state in the singlet excited state which causes the fluorescence to exhibit dual emission. The normal or planar conformation (LE) occurs at the shorter wavelength due to coupling of the lone pair of electrons on the proximal amine with the electrons on the p-orbital of the aromatic naphthalimide. The other conformation exists as the longer wavelength, or anomalous band, is described as the twisted intramolecular charge transfer (TICT) state, arising from the decoupling of the electron pairs. The phenomenon of molecular fluorescence possesses many features that make it suitable for real-time monitoring and responding to atomic and molecular species. It is shown in this work that this naphthalimide is an efficient system where measurable spectral changes in the locally excited state and TICT state are dependent upon transition metal complexation, pH, and temperature. It is observed that a fluorescence enhancement of the LE state occurs at acidic pH, high temperatures, or in the presence of complexing metal ions, whereas the TICT state predominates at basic pH levels, lower temperatures or the absence of complexing metal ions. Because these cnvironmcnlal changes affect the naphthalimide\u27s equilibrium between the TICT excited state and LE excited state, the ratio of the TICT and LE excited states can be used to measure physical properties of the naphthalirnide such as the metal binding affinity and pKa values. The photophysical properties of this sensor and its fluorescence response toward the changing environment of metal complexation, pH and temperature are reported here
Quantum Cascade Laser Infrared Spectroscopy for Online Monitoring of Hydroxylamine Nitrate
We describe a new approach for high sensitivity and real-time online measurements to monitor the kinetics in the processing of nuclear materials and other chemical reactions. Mid infrared (Mid-IR) quantum cascade laser (QCL) high-resolution spectroscopy was used for rapid and continuous sampling of nitrates in aqueous and organic reactive systems, using pattern recognition analysis and high sensitivity to detect and identify chemical species. In this standoff or off-set method, the collection of a sample for analysis is not required. To perform the analysis, a flow cell was used for in situ sampling of a liquid slipstream. A prototype was designed based on attenuated total reflection (ATR) coupled with the QCL beam to detect and identify chemical changes and be deployed in hostile environments, either radiological or chemical. The limit of detection (LOD) and the limit of quantification (LOQ) at 3σ for hydroxylamine nitrate ranged from 0.3 to 3 and from 3.5 to 10 g·L−1, respectively, for the nitrate system at three peaks with wavelengths between 3.8 and 9.8 μm
Sequential Stereotype Priming: A Meta-Analysis
© 2017, 2017 by the Society for Personality and Social Psychology, Inc. Psychological interest in stereotype measurement has spanned nearly a century, with researchers adopting implicit measures in the 1980s to complement explicit measures. One of the most frequently used implicit measures of stereotypes is the sequential priming paradigm. The current meta-analysis examines stereotype priming, focusing specifically on this paradigm. To contribute to ongoing discussions regarding methodological rigor in social psychology, one primary goal was to identify methodological moderators of the stereotype priming effect—whether priming is due to a relation between the prime and target stimuli, the prime and target response, participant task, stereotype dimension, stimulus onset asynchrony (SOA), and stimuli type. Data from 39 studies yielded 87 individual effect sizes from 5,497 participants. Analyses revealed that stereotype priming is significantly moderated by the presence of prime–response relations, participant task, stereotype dimension, target stimulus type, SOA, and prime repetition. These results carry both practical and theoretical implications for future research on stereotype priming