Synergistic effects between nitrogen functionalities and metals content on the removal of phosphate ions

The release of phosphate ions in the runoff is today a major threat to the environment and humans. Therefore, it is vital to develop effective technologies to remove phosphate ions from aqueous solutions before they are discharged into runoff and natural water bodies. This study aims to evaluate and proposed a mechanism of phosphate adsorption by using nitrogen and metals-functionalized chars. In order to isolate the contribution of individual components of lignocellulosic biomass, simple cellulose was used for the char production. Five samples of nitrogen-doped chars were produced via annealing cellulose under ammonia gas at different temperatures (500, 600, 700, 800, 850 and 900 ℃). Some of the analytical techniques used for the chars characterization were: Elemental and proximate analysis, gas physisorption analysis, Scanning Electron Microscopy and X-ray photoelectron spectroscopy analysis. These samples were subsequently used for phosphate adsorption. Characterization of the resulting chars shows an increase of the nitrogen content in the samples, where the greater percentage of it appears at a temperature of 800 ℃ (12.5 wt%) and the maximum surface area was for char produced at 900 ℃ (1314 m2/g). To evaluate the effect of nitrogen and metals in char to adsorb phosphate ions, three sets of chars were produced at 800 ℃; char with magnesium and nitrogen (Mg_N_char); char with nitrogen (N_char) and char with magnesium (Mg_N_char). The results show that Mg_N_char sample exhibits a maximum adsorption capacity of 340 mg/g, whereas the Mg_char and N_char samples give an adsorption capacity of 7.8 mg/g and 21.4 mg/g respectively. These results demonstrate that the presence of magnesium and nitrogen in chars is very effective in the retention of phosphate ions. Other metals such as Fe and Ca combined with nitrogen will also be tested, details of the results will be presented at the conference

Radiofrequency Ablation Using a Novel Insulated-Tip Ablation Catheter Can Create Uniform Lesions Comparable in Size to Conventional Irrigated Ablation Catheters While Using a Fraction of the Energy and Irrigation

[EN] Introduction: During radiofrequency ablation (RFA) using conventional RFA catheters (RFC), similar to 90% of the energy dissipates into the bloodstream/surrounding tissue. We hypothesized that a novel insulated-tip ablation catheter (SMT) capable of blocking the radiofrequency path may focus most of the energy into the targeted tissue while utilizing reduced power and irrigation. Methods: This study evaluated the outcomes of RFA using SMT versus an RFC in silico, ex vivo, and in vivo. Radiofrequency applications were delivered over porcine myocardium (ex vivo) and porcine thigh muscle preparations superfused with heparinized blood (in vivo). Altogether, 274 radiofrequency applications were delivered using SMT (4-15 W, 2 or 20 ml/min) and 74 applications using RFC (30 W, 30 ml/min). Results: RFA using SMT proved capable of directing 66.8% of the radiofrequency energy into the targeted tissue. Accordingly, low power-low irrigation RFA using SMT (8-12 W, 2 ml/min) yielded lesion sizes comparable with RFC, whereas high power-high irrigation (15 W, 20 ml/min) RFA with SMT yielded lesions larger than RFC (p < .05). Although SMT was associated with greater impedance drops ex vivo and in vivo, ablation using RFC was associated with increased charring/steam pop/ tissue cavitation (p < .05). Lastly, lesions created with SMT were more homogeneous than RFC (p < .001). Conclusion: Low power-low irrigation (8-12 W, 2 ml/min) RFA using the novel SMT ablation catheter can create more uniform, but comparable-sized lesions as RFC with reduced charring/steam pop/tissue cavitation. High power-high irrigation (15 W, 20 ml/min) RFA with SMT yields lesions larger than RFC.Sirona Medical Technologies, Inc; The Proyecto UNAJ Investiga 2017, Grant/Award Number: 80020170100019UJ; The Spanish Ministerio de Ciencia, Innovacion y Universidades/Agencia Estatal de Investigacion (MCIN/AEI/10.13039/501100011033), Grant/Award Number: RTI2018-094357B-C21Aryana, A.; Irastorza, RM.; Berjano, E.; Cohen, RJ.; Kraus, J.; Haghighi-Mood, A.; Reddy, VY.... (2022). Radiofrequency Ablation Using a Novel Insulated-Tip Ablation Catheter Can Create Uniform Lesions Comparable in Size to Conventional Irrigated Ablation Catheters While Using a Fraction of the Energy and Irrigation. Journal of Cardiovascular Electrophysiology. 33(6):1146-1156. https://doi.org/10.1111/jce.154611146115633

A novel hybrid organosolv: steam explosion method for the efficient fractionation and pretreatment of birch biomass

Background: The main role of pretreatment is to reduce the natural biomass recalcitrance and thus enhance sac- charification yield. A further prerequisite for efficient utilization of all biomass components is their efficient fractiona- tion into well-defined process streams. Currently available pretreatment methods only partially fulfill these criteria. Steam explosion, for example, excels as a pretreatment method but has limited potential for fractionation, whereas organosolv is excellent for delignification but offers poor biomass deconstruction. Results: In this article, a hybrid method combining the cooking and fractionation of conventional organosolv pre - treatment with the implementation of an explosive discharge of the cooking mixture at the end of pretreatment was developed. The effects of various pretreatment parameters (ethanol content, duration, and addition of sulfuric acid) were evaluated. Pretreatment of birch at 200 °C with 60% v/v ethanol and 1% w/w biomass H 2 SO 4 was proven to be the most efficient pretreatment condition yielding pretreated solids with 77.9% w/w cellulose, 8.9% w/w hemicellulose, and 7.0 w/w lignin content. Under these conditions, high delignification of 86.2% was demonstrated. The recovered lignin was of high purity, with cellulose and hemicellulose contents not exceeding 0.31 and 3.25% w/w, respectively, and ash to be < 0.17% w/w in all cases, making it suitable for various applications. The pretreated solids presented high saccharification yields, reaching 68% at low enzyme load (6 FPU/g) and complete saccharification at high enzyme load (22.5 FPU/g). Finally, simultaneous saccharification and fermentation (SSF) at 20% w/w solids yielded an ethanol titer of 80 g/L after 192 h, corresponding to 90% of the theoretical maximum. Conclusions: The novel hybrid method developed in this study allowed for the efficient fractionation of birch biomass and production of pretreated solids with high cellulose and low lignin contents. Moreover, the explosive dis- charge at the end of pretreatment had a positive effect on enzymatic saccharification, resulting in high hydrolyzability of the pretreated solids and elevated ethanol titers in the following high-gravity SSF. To the best of our knowledge, the ethanol concentration obtained with this method is the highest so far for birch biomass

Full wavefunction optimization with quantum Monte Carlo : and its effect on the quality of nodal surfaces of transition metal compounds

For the first time, quantum Monte Carlo orbital optimization of multi-configuration wave functions for transition metal compounds are performed. Diffusion quantum Monte Carlo calculations with partial and full optimization of the guide function are carried out for the dissociation of diatomic transition metal molecules. It is demonstrated that the wavefunction optimization of explicitly correlated wave functions at the variational Monte Carlo level can systematically improve the accuracy of the fixed node diffusion Monte Carlo calculation. In particular energy optimization of the orbitals of a complete active space wave function in the presence of a Jastrow correlation function is required to obtain agreement with the experimental dissociation energy. Furthermore, in the case of FeS it is shown that orbital optimization leads to a correct prediction of the ground state whereas other high-level ab initio wave function calculations fail. The role of the Jastrow factor in DMC calculations with pseudopotentials is investigated. The results suggest that a large Jastrow factor may improve the DMC accuracy substantially at small additional cost

Analysis of phonocardiographic signals using advanced signal processing techniques

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