A quasi-hexagonal prism-shaped carbon nitride for photoreduction of carbon dioxide under visible light

Abstract

A quasi-hexagonal prism-shaped carbon nitride (H-C₃N₄) was synthesized from urea-derived C₃N₄ (U-C₃N₄) using an alkaline hydrothermal process. U-C₃N₄ decomposition followed by hydrogen bond rearrangement of hydrolyzed products leads to the formation of a quasi-hexagonal prism-shaped structure. The H-C₃N₄ catalysts displayed superior activity in the photoreduction of CO₂ with H₂O compared to U-C₃N₄. The enhanced photocatalytic activities can be attributed to the promotion of incompletely coordinated nitrogen atom formation in the C₃N₄ molecules.

Graphical abstract

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Removal and recovery of phosphate from water by calcium-silicate composites-novel adsorbents made from waste glass and shells

Abstract

The removal and recovery of phosphate from water by calcium-silicate composite (CSC) and alkali-treated calcium-silicate composite (ASC) was investigated. ASC had a higher specific surface area and total pore volume, and exhibited better performance of phosphate adsorption than CSC. In the batch mode adsorption studies, the isotherm adsorption experiments data fitted well the Langmuir isotherm model and the maximum adsorption capacities were 120 and 73.0 mg/g for ASC and for CSC, respectively. For the kinetic study, the experimental data fitted very well the pseudo-second-order kinetic model. The uptake of phosphate could be performed well over a wide pH range, from 3.0 to 13.0 for ASC and from 4.0 to 13.0 for CSC. The adsorption of phosphate by ASC was very selective even with 10 times higher concentration of other coexistent anions. For the adsorption of low phosphate concentration (10 mg/L), ASC could efficiently remove phosphate at the dosage of 0.8 g/L, while CSC was even difficult to remove phosphate at the dosage of 4.0 g/L. Phosphate fractionation results and FTIR spectra showed that phosphate-Ca complex was formed through phosphate adsorption process. The adsorbed phosphate could be successfully desorbed by 2% citric acid solution, indicating that the adsorbent after adsorbed phosphate could be reusable as fertilizer in the agricultural field.

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Successful dorsomedial prefrontal rTMS for major depression in borderline personality disorder: three cases

Publication date: Available online 2 February 2017
Source:Brain Stimulation
Author(s): Kfir Feffer, Sarah K. Peters, Kamaldeep Bhui, Peter Giacobbe, Jonathan Downar




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Reliability of TMS phosphene threshold estimation: toward a standardized protocol

Publication date: Available online 2 February 2017
Source:Brain Stimulation
Author(s): Chiara Mazzi, Silvia Savazzi, Arman Abrahamyan, Manuela Ruzzoli
BackgroundPhosphenes induced by transcranial magnetic stimulation (TMS) are a subjectively described visual phenomenon employed in basic and clinical research as index of the excitability of retinotopically organized areas in the brain.ObjectivePhosphene threshold estimation is a preliminary step in many TMS experiments in visual cognition for setting the appropriate level of TMS doses; however, the lack of a direct comparison of the available methods for phosphene threshold estimation leaves unsolved the reliability of those methods in setting TMS doses. The present work aims at fulfilling this gap.MethodsWe compared the most common methods for phosphene threshold calculation, namely the Method of Constant Stimuli (MOCS), the Modified Binary Search (MOBS) and the Rapid Estimation of Phosphene Threshold (REPT). In two experiments we tested the reliability of PT estimation under each of the three methods, considering the day of administration, the participants' expertise in phosphene perception and the sensitivity of each method to the initial values used for the threshold calculation.ResultsWe found that MOCS and REPT have comparable reliability when estimating phosphene thresholds, while MOBS estimations appear less stable.ConclusionsBased on our results, researchers and clinicians can estimate phosphene threshold according to MOCS or REPT equally reliably, depending on their specific investigation goals. We suggest several important factors for consideration when calculating phosphene thresholds and describe strategies to adopt in experimental procedures.



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Validating Safecast data by comparisons to a U. S. Department of Energy Fukushima Prefecture aerial survey

Publication date: May 2017
Source:Journal of Environmental Radioactivity, Volume 171
Author(s): Mark Coletti, Carolynne Hultquist, William G. Kennedy, Guido Cervone
Safecast is a volunteered geographic information (VGI) project where the lay public uses hand-held sensors to collect radiation measurements that are then made freely available under the Creative Commons CC0 license. However, Safecast data fidelity is uncertain given the sensor kits are hand assembled with various levels of technical proficiency, and the sensors may not be properly deployed. Our objective was to validate Safecast data by comparing Safecast data with authoritative data collected by the U. S. Department of Energy (DOE) and the U. S. National Nuclear Security Administration (NNSA) gathered in the Fukushima Prefecture shortly after the Daiichi nuclear power plant catastrophe. We found that the two data sets were highly correlated, though the DOE/NNSA observations were generally higher than the Safecast measurements. We concluded that this high correlation alone makes Safecast a viable data source for detecting and monitoring radiation.



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Modeling watershed-scale 137Cs transport in a forested catchment affected by the Fukushima Dai-ichi Nuclear Power Plant accident

Publication date: May 2017
Source:Journal of Environmental Radioactivity, Volume 171
Author(s): Lezhang Wei, Tsuyoshi Kinouchi, Kazuya Yoshimura, Mark L. Velleux
The Fukushima nuclear accident in 2011 resulted in ¹³⁷Cs contamination of large areas in northeast Japan. A watershed-scale ¹³⁷Cs transport model was developed and applied to a forested catchment in Fukushima area. This model considers ¹³⁷Cs wash-off from vegetation, movement through soils, and transport of dissolved and particulate ¹³⁷Cs adsorbed to clay, silt and sand. Comparisons between measurements and simulations demonstrated that the model well reproduced ¹³⁷Cs concentrations in the stream fed from the catchment. Simulations estimated that 0.57 TBq of ¹³⁷Cs was exported from the catchment between June, 2011 and December, 2014. Transport largely occurred with eroded sediment particles at a ratio of 17:70:13 of clay, silt, and sand. The overall ¹³⁷Cs reduction ratio by rainfall-runoff wash-off was about 1.6%. Appreciable ¹³⁷Cs remained in the catchment at the end of 2014. The largest rate of ¹³⁷Cs reduction by wash-off was simulated to occur in subwatersheds of the upper catchment. However, despite relatively low initial deposition, middle portions of the watershed exported proportionately more ¹³⁷Cs by rainfall-runoff processes. Simulations indicated that much of the transported ¹³⁷Cs originates from erosion over hillsides and river banks. These results suggested that areas where ¹³⁷Cs accumulates with redeposited sediments can be targeted for decontamination and also provided insight into ¹³⁷Cs transport at the watershed scale to assess risk management and decontamination planning efforts.



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Temporal Stability of Multiple Response Systems to 7.5% Carbon Dioxide Challenge

Publication date: Available online 2 February 2017
Source:Biological Psychology
Author(s): Roxann Roberson-Nay, Eugenia I. Gorlin, Jessica R. Beadel, Therese Cash, Scott Vrana, Bethany A. Teachman
Self-reported anxiety, and potentially physiological response, to maintained inhalation of carbon dioxide (CO2) enriched air shows promise as a putative marker of panic reactivity and vulnerability. Temporal stability of response systems during low-dose, steady-state CO2 breathing challenge is lacking. Outcomes on multiple levels were measured two times, one week apart, in 93 individuals. Stability was highest during the CO2 breathing phase compared to pre-CO2 and recovery phases, with anxiety ratings, respiratory rate, skin conductance level, and heart rate demonstrating good to excellent temporal stability (ICCs ≥ 0.71). Cognitive symptoms tied to panic were somewhat less stable (ICC=0.58) than physical symptoms (ICC=0.74) during CO2 breathing. Escape/avoidance behaviors and DSM-5 panic attacks were not stable. Large effect sizes between task phases also were observed. Overall, results suggest good-excellent levels of temporal stability for multiple outcomes during respiratory stimulation via 7.5% CO2.



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