Importance of Bridging Molecular and Process Modeling to Design Optimal Adsorbents for Large-Scale CO2 Capture.

ConspectusCarbon capture, utilization, and storage have been identified as key technologies to decarbonize the energy and industrial sectors. Although postcombustion CO2 capture by absorption in aqueous amines is a mature technology, the required high regeneration energy, losses due to degradation and evaporation, and corrosion carry a high economic cost, precluding this technology to be used today at the scale required to mitigate climate change. Solid adsorbent-based systems with high CO2 capacities, high selectivity, and lower regeneration energy are becoming an attractive alternative for this purpose. Conscious of this opportunity, the search for optimal adsorbents for the capture of CO2 has become an urgent task. To accurately assess the performance of CO2 separation by adsorption at the needed scale, adsorbents should be synthesized and fully characterized under the required operating conditions, and the proper design and simulation of the process should be implemented along with techno-economic and environmental assessments. Several works have examined pure CO2 single-component adsorption or binary mixtures of CO2 with nitrogen for different families of adsorbents, primarily addressing their CO2 adsorption capacity and selectivity; however, very limited data is available under other conditions and/or with impurities, mainly due to the intensive experimental (modeling) efforts required for the large number of adsorbents to be studied, posing a challenge for their assessment under the needed conditions. In this regard, molecular simulations can be employed in synergy with experiments, reliably generating missing adsorption properties of mixtures while providing understanding at the molecular level of the mechanism of the adsorption process.This Account provides an outlook on strategies used for the rational design of materials for CO2 capture from different sources from the understanding of the adsorption mechanism at the molecular level. We illustrate with practical examples from our work and others' work how molecular simulations can be reliably used to link the molecular knowledge of novel adsorbents for which limited data exist for CO2 capture adsorption processes. Molecular simulation results of different adsorbents, including MOFs, zeolites, and carbon-based and silica-based materials, are discussed, focusing on understanding the role of physical and chemical adsorption obtained from simulations and quantifying the impact of impurities in the performance of the materials. Furthermore, simulation results can be used for screening adsorbents from basic key performance indicators, such as cycling the working capacity, selectivity, and energy requirement, or for feeding detailed dynamic models to assess their performance in swing adsorption processes on the industrial scale, additionally including monetized performance indicators such as operating expenses, equipment sizes, and compression cost. Moreover, we highlight the role of molecular simulations in guiding strategies for improving the performance of these materials by functionalization with amines or creating hybrid solid materials. We show how integrating models at different scales provides a robust and reliable assessment of the performance of the adsorbent materials under the required industrial conditions, rationally guiding the search for best performers. Trends in additional computational resources that can be used, including machine learning, and perspectives on practical requirements for leveraging CO2 capture adsorption technologies on the needed scale are also discussed.

Bloodstream infection by Rhodococcus corynebacterioides in a pediatric patient diagnosed with high-risk retinoblastoma.

Rhodococcus is a pathogen that is known to cause infections in animals and humans, mainly in cases of immunocompromised patients. A case of a pediatric cancer patient suffering from a bloodstream infection caused by Rhodococcus corynebacterioides was described in this work. Gram positive rods were isolated from blood cultures. The target bacterium was identified using a combination of biochemical tests, the MALDI-TOF mass spectrometry technique, and the analysis of the 16S rRNA sequence. Moreover, an antimicrobial susceptibility test was performed using the E-test. The isolated bacterium was identified as R. corynebacterioides. The 3-year-old patient was successfully treated with vancomycin and meropenem. This is the first published report of R. corynebacterioides in a pediatric patient diagnosed with retinoblastoma that developed a bloodstream infection. R. corynebacterioides should be considered among the opportunistic infectious agents affecting pediatric cancer patients.

High occurrence of CRLF2 abnormalities in Mexican children with B-cell acute lymphoblastic leukemia.

The P2RY8-CRLF2 and IGH-CRLF2 rearrangements induce the overexpression of cytokine receptor-like factor 2 (CRLF2) and have been associated with relapse and poor prognosis in B-cell acute lymphoblastic leukemia (B-ALL). Additionally, they are frequently documented in high-risk Hispanic populations. To better understand the potential causes of the adverse prognosis of childhood B-ALL in Mexico, we analyzed these rearrangements and the CRLF2 mRNA and protein levels in 133 Mexican children with B-ALL. We collected bone marrow samples at diagnosis and evaluated the CRLF2 gene expression by qRT-PCR and the total CRLF2 protein by flow cytometry. P2RY8-CRLF2 and IGH-CRLF2 were detected by RT-PCR and FISH, respectively. The median time of follow-up to determine the prognostic significance of the CRLF2 abnormalities was three years. In 82% of the participants, the mRNA levels correlated with the cell-surface and intracellular CRLF2 protein levels. The P2RY8-CRLF2 rearrangement was present in 31.5% (42/133) of the patients, while the IGH-CRLF2 rearrangement was detected in 13.5% (9/67) of patients with high expression of CRLF2 (6.8% of the total sample). CRLF2 copy number variations (gain) were also detected in 7.5% (5/67) of patients with high protein levels. The overall survival (OS) presented significantly lower rates in patients with high white blood cell count (≥50x109/L) regardless of CRLF2 expression, but high levels of CRLF2 gene expression appears to contribute to the reduction of OS within this group of patients. In conclusion, in our cohort, a high occurrence of CRLF2 abnormalities was documented, particularly the P2RY8-CRLF2 rearrangement, which might represent a characteristic of the Mexican population. Targeted therapy to treat this group of patients could improve OS.

Characterization of Philadelphia-like Pre-B Acute Lymphoblastic Leukemia: Experiences in Mexican Pediatric Patients.

Ph-like subtypes with CRLF2 abnormalities are frequent among Hispano-Latino children with pre-B ALL. Therefore, there is solid ground to suggest that this subtype is frequent in Mexican patients. The genomic complexity of Ph-like subtype constitutes a challenge for diagnosis, as it requires diverse genomic methodologies that are not widely available in diagnostic centers in Mexico. Here, we propose a diagnostic strategy for Ph-like ALL in accordance with our local capacity. Pre-B ALL patients without recurrent gene fusions (104) were classified using a gene-expression profile based on Ph-like signature genes analyzed by qRT-PCR. The expressions of the CRLF2 transcript and protein were determined by qRT-PCR and flow cytometry. The P2RY8::CRLF2, IGH::CRLF2, ABL1/2 rearrangements, and Ik6 isoform were screened using RT-PCR and FISH. Surrogate markers of Jak2-Stat5/Abl/Ras pathways were analyzed by phosphoflow. Mutations in relevant kinases/transcription factors genes in Ph-like were assessed by target-specific NGS. A total of 40 patients (38.5%) were classified as Ph-like; of these, 36 had abnormalities associated with Jak2-Stat5 and 4 had Abl. The rearrangements IGH::CRLF2,P2RY8::CRLF2, and iAMP21 were particularly frequent. We propose a strategy for the detection of Ph-like patients, by analyzing the overexpression/genetic lesions of CRLF2, the Abl phosphorylation of surrogate markers confirmed by gene rearrangements, and Sanger sequencing.

Unveiling the phase behavior of CiEj non-ionic surfactants in water through coarse-grained molecular dynamics simulations.

Poly(oxyethylene) alkyl ethers, usually denoted by CiEj surfactants, exhibit a rich phase behavior in water, self-assembling to form a variety of 3-D structures with a controllable morphology that find multiple applications across different industrial segments. Hence, being able to describe and understand the effect of molecular structure on the phase behavior of these systems is highly relevant for the efficient design of new materials and their applications. Considering the promising results obtained over the last decade using the MARTINI model to describe ethylene-oxide containing compounds, an extensive assessment of the ability of such a model to describe the phase behavior of CiEj in water was carried out and results are presented here. Given the overall poor temperature transferability of the MARTINI model, mostly due to the lack of an accurate representation of hydrogen bonding, simulations were carried out at a single temperature of 333 K, where most phases are expected to occur according to experiments. Different chain lengths of both the hydrophobic and hydrophilic moieties, spanning a wide range of hydrophilic-lipophilic balance values, were investigated and the phase diagrams of various CiEj surfactants explored over a wide concentration range. The model was able to satisfactorily describe the effect of surfactant structure and concentration on mesophase formation. The stability and dimensions of the obtained phases, and the prediction of some unique features such as the characterization of a singular lamellar phase are presented. The results obtained in this work highlight both the predictive ability and the transferability of the MARTINI forcefield in the description of such systems. Moreover, the model was shown to provide adequate descriptions of the micellar phase in terms of micelle dimensions, critical micelle concentration, and average aggregation number.

Quantifying the effect of polar interactions on the behavior of binary mixtures: Phase, interfacial, and excess properties.

In this work, polar soft-Statistical Associating Fluid Theory (SAFT) was used in a systematic manner to quantify the influence of polar interactions on the phase equilibria, interfacial, and excess properties of binary mixtures. The theory was first validated with available molecular simulation data and then used to isolate the effect of polar interactions on the thermodynamic behavior of the mixtures by fixing the polar moment of one component while changing the polar moment of the second component from non-polar to either highly dipolar or quadrupolar, examining 15 different binary mixtures. It was determined that the type and magnitude of polar interactions have direct implications on the vapor-liquid equilibria (VLE), resulting in azeotropy for systems of either dipolar or quadrupolar fluids when mixed with non-polar or low polar strength fluids, while increasing the polar strength of one component shifts the VLE to be more ideal. Additionally, excess properties and interfacial properties such as interfacial tension, density profiles, and relative adsorption at the interface were also examined, establishing distinct enrichment in the case of mixtures with highly quadrupolar fluids. Finally, polar soft-SAFT was applied to describe the thermodynamic behavior of binary mixtures of experimental systems exhibiting various intermolecular interactions (non-polar and polar), not only demonstrating high accuracy and robustness through agreement with experimental data but also providing insights into the effect of polarity on the interfacial properties of the studied mixtures. This work proves the value of having an accurate theory for isolating the effect of polarity, especially for the design of ad hoc polar solvents.

Patient and health service factors associated with delays in cancer treatment for children without social security in Mexico.

BACKGROUND: The objective was to investigate factors associated with patient-related timing (PRT) to seek healthcare and health service-related timing (HSRT) to diagnose cancer and provide treatment to children without social security in Mexico. PROCEDURE: A cross-sectional survey was conducted in 13 Ministry of Health hospitals in the states of Chihuahua, Jalisco, Mexico City, Morelos, Oaxaca, Puebla, Queretaro, State of Mexico, and Tlaxcala. Study participants were parents of recently diagnosed pediatric cancer patients (≤ 17 years of age). Three groups of factors were investigated: (1) patients (child and parent characteristics); (2) healthcare providers (HCPs) (first-contact HCP, institution, perceptions of barriers to healthcare, etc.); and (3) disease factors (cancer type/site, stage/risk at diagnosis). PRT and HSRT-associated factors were identified using multiple negative binomial regressions. RESULTS: The study included 265 children; 49% sought care when symptoms first appeared. The median PRT was seven days, and the median HSRT was 40 days. Parents' perceptions of long wait times for appointments were associated with longer PRT and HSRT. Residing in the lowest or highest socioeconomic regions and persistent or worsening symptoms increased the probability of longer PRT. Older patient age, HCP requests for imaging tests or prescription for steroids, a higher number of doctors consulted, having a urinary tract cancer, and having an advanced stage or high-risk cancer increased the probability of longer HSRT. CONCLUSION: Strategies to shorten lag time from symptom onset to diagnosis and treatment are urgently needed for childhood cancers in Mexico.

Polar soft-SAFT: theory and comparison with molecular simulations and experimental data of pure polar fluids.

The consideration of polar interactions is of vital importance for the development of predictive and accurate thermodynamic models for polar fluids, as they govern most of their thermodynamic properties, making them highly non-ideal fluids. We present here for the first time the extension of the soft-SAFT equation of state (EoS), named polar soft-SAFT, to explicitly model intermolecular polar interactions (dipolar and quadrupolar), using the approach of Jog and Chapman (P. K. Jog and W. G. Chapman, Mol. Phys., 1999, 97(3), 307-319). The theory is first validated using molecular simulation data for a wide range of polar model systems including Stockmayer fluids, LJ dimers with dipole, and quadrupolar LJ fluids, for a wide range of thermophysical properties such as liquid density, vapour pressure, surface tension and heat capacities. Excellent agreement between polar soft-SAFT and simulation data has been obtained for all examined fluids and properties for systems exhibiting low to intermediate polar strength, while the agreement deteriorates at very high polar strengths. Once validated with simulations, the equation has been applied to calculate vapour-liquid equilibria (VLE), surface tension and second-order derivative properties of systems such as 2-ketone and methane chloride families as showcases for dipolar fluids and the benzene family for quadrupolar fluids, finding very good agreement with experimental data. In order to preserve the robustness of the model, the experimental value of the dipole or quadrupole was used in these calculations, while the additional parameter for the polar fluids was set a priori rather than included in the fitting procedure. The excellent agreement found with simulations and experiments empowers the soft-SAFT equation with new capabilities for the development of robust and accurate molecular models of polar fluids of industrial relevance.

Interfacial anomaly in low global warming potential refrigerant blends as predicted by molecular dynamics simulations.

Understanding the phase behavior and accurately predicting the thermophysical, interfacial and transport properties of low global warming, fourth generation refrigerants is essential for designing and evaluating refrigeration cycle performances and determining the optimal refrigerant or blends for a selected application. In this paper, we have used molecular dynamics simulations to study the vapour-liquid interface of fourth generation refrigerants including 2,3,3,3-tetrafluoropropene (HFO-1234yf), trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), methylpropane (isobutane, HC-600a) and binary mixtures containing HFO-1234yf + HC-600a and HFO-1234ze(E) + HC-600a as new alternatives to third generation refrigerants. We provide predictions on their vapour-liquid equilibrium and interfacial properties (such as density profiles, interface thickness and surface tension) derived from the simulations. The results are compared to the experimental data, when available, and calculations made using the statistical associating fluid theory (SAFT). It is found that the mixtures of HFO-1234yf + HC-600a and HFO-1234ze(E) + HC-600a present azeotropic and aneotropic behavior. Molecular dynamics simulations corroborate the aneotrope already predicted by SAFT for these mixtures, highlighting the robustness of using molecular modeling techniques to investigate the performance of low GWP refrigerants and their blends as complementary tools to obtain the required data for the optimization of these systems. Insights into the molecular behavior at compositions before the aneotrope, at the aneotrope and after the aneotrope are provided based on radial distribution functions. It is shown that HC-600a and HFO molecules tend to stay closer to the same type of molecules and accumulate at different sides of the liquid region to act like pure components at the aneotropic composition.

Insights into the influence of the molecular structures of fluorinated ionic liquids on their thermophysical properties. A soft-SAFT based approach.

Fluorinated ionic liquids (FILs) are a unique family of ionic liquids with remarkable properties, including the formation of three nano-segregated domains, which are very attractive for several emerging applications. However, the amount of available experimental data to fully characterize them is very scarce. We propose a systematic methodology to build FIL transferable molecular models within the soft-SAFT framework to describe the behaviour of FILs and their mixtures. A total of 38 FILs (pyridinium- and imidazolium-based FILs conjugated with fluorinated anions such as [N(CF3SO2)2]-, [CF3SO3]-, [CF3CO2]-, [C4F9SO3]- and [C4F9CO2]-) have been modelled for this purpose using available data, paying special attention to the physical meaning of the parameters. The models are used to obtain molecular insights into the influence of the anion and cation molecular structures on the thermophysical properties of the FILs. It is concluded that the anion and anion fluorination are the leading features in the thermophysical properties investigated, as captured by soft-SAFT. Models for three FILs not included in the parametrization study were built from the transferable parameters, in excellent agreement with experimental data, underlining the robustness of the soft-SAFT approach. The methodology presented here allows a direct connection between the molecular characteristics of the FILs, the influence on their behaviour, and how this can be captured by a molecular-based equation of state. The procedure allows assembling FIL models with high predictive capabilities in an intuitive way regarding the process of parametrization from the molecular structure, allowing us to characterize their thermophysical behaviour where limited experimental data are available.

A methodology to parameterize SAFT-type equations of state for solid precursors of deep eutectic solvents: the example of cholinium chloride.

Given the recent boom of applications for deep eutectic solvents (DES), there is a need for robust and accurate thermodynamic models that are able to describe them. Recent works have used molecular-based equations of state, derived from the Statistical Associating Fluid Theory (SAFT), to model DES due to their ability to explicitly account for hydrogen bonding, which is thought to govern the formation of a DES. However, the application of these association models to DES is a non-trivial task, because pure fluid data for several DES precursors are not available to be used in the model parameterization. The alternative parameterization procedures currently employed have evident flaws including the use of oversimplified association schemes, lack of transferability, inability to provide fundamental solid-liquid equilibrium data, and an overall poor accuracy. This work highlights the disadvantages of the current approaches while providing a novel methodology for the development of coarse-grained models applicable to DES. By proposing a more realistic association scheme and regressing the model parameters from experimental data that can be easily measured for a representative DES, a new coarse-grained model for [Ch]Cl, the most used DES precursor, was developed for soft-SAFT. The good performance and versatility of the new model were then successfully demonstrated through the modelling of a wide variety of [Ch]Cl-based DES, providing accurate descriptions of densities, vapor-liquid equilibria and solid-liquid equilibria data, for both binary and ternary systems. Furthermore, the novel approach can easily be applied to other SAFT-type models and extended to other solid DES precursors such as urea.

Thermophysical Characterization of Ionic Liquids Based on the Perfluorobutanesulfonate Anion: Experimental and Soft-SAFT Modeling Results.

Fluorinated ionic liquids (FILs) exhibit complex molecular behavior, where three different nanodomains (polar, hydrogenated nonpolar, and fluorinated nonpolar) have been identified by molecular simulations. Given the high number of possible anion/cation combinations, a theoretical tool able to describe the thermophysical properties of these compounds in a systematic, rapid, and accurate manner is highly desirable. We present here a combined experimental-theoretical methodology to obtain the phase, interface, and transport properties of the 1-alkyl-3-methylimidazolium perfluorobutanesulfonate ([Cn C1 Im][C4 F9 SO3 ]) family. In addition to providing new experimental data, an extended version of the Statistical Associating Fluid Theory (soft-SAFT) is used to describe the physicochemical behavior of the [Cn C1 Im][C4 F9 SO3 ] family. A mesoscopic molecular model is built based on the analysis of the chemical structures of these FILs, and supported by quantum chemical calculations to study the charge distribution of the anion, where only the basic physical features are considered. The resulting molecular parameters are related to the molecular weight, providing the basis for thermophysical predictions of similar compounds. The theory is also able to predict the minimum in the surface tension versus the length of the hydrogenated alkyl chain, experimentally found at n=8. The viscosity parameters are also in agreement with the free-volume calculations obtained from experiments.

Pharmaceutical Removal from Water Effluents by Adsorption on Activated Carbons: A Monte Carlo Simulation Study.

Adsorption on activated carbons of five pharmaceutical molecules (ibuprofen, diclofenac, naproxen, paracetamol, and amoxicillin) in aqueous mixtures has been investigated by molecular simulations using the Grand Canonical Monte Carlo (GCMC) method. A virtual nanoporous carbon model based on polyaromatic units with defects and polar-oxygenated sites was used for this purpose. The simulation results show excellent agreement with available experimental data. The adsorption capacities of the carbons for the five drugs were quite different and were linked, essentially, to their molecular dimensions and atom affinities. The uptake behavior follows the trend PRM > DCF, NPX > IBP > AMX in all the studied structures. This work is a further step in order to describe macroscopic adsorption performance of activated carbons in drug removal applications.

The phase and interfacial properties of azeotropic refrigerants: the prediction of aneotropes from molecular theory.

The use of hydrofluorocarbons (HFCs) as alternative non-ozone depleting refrigerants for chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) has grown during the last couple of decades. Owing to their considerable global warming potential, a global deal has been reached recently to limit the production and consumption of HFCs. For rational design of new refrigerants that are environmentally friendlier, the thermodynamics of current ones need to be well understood first. In this work, we examine the phase behavior of azeotropic refrigerants obtained by mixing HFCs with normal alkanes. The vapor-liquid equilibria (VLE) of these binary systems exhibit positive deviation from Raoult's law in the bulk, and a negative deviation from surface ideality (aneotrope) at the interface. The phase equilibria, second order thermodynamic derivative properties and interfacial properties of these complex systems were studied here using a modified version of the Statistical Associating Fluid Theory (SAFT) combined with Density Gradient Theory (DGT). The model was able to accurately capture the azeotropic nature of the phase equilibria and predict their composition and pressure at temperatures where experimental data are limited. In addition, accurate descriptions of the interfacial tensions were also obtained when compared with available experimental data, predicting the minimum found in surface tension as a function of composition. The molecular-based theory allowed the calculation of interfacial properties for which there is no experimental data available yet. Predictions show that the aneotrope occurs at a lower HFC composition for R-152a and R-134a systems in comparison to R-143a and R-125 systems. According to the calculated density profiles, HFC molecules appear to be preferentially adsorbed at the interface causing the surface tension of the n-alkane rich phase to decrease at low HFC concentrations. At high HFC concentrations, the phenomenon is inverted and n-alkane molecules are preferentially adsorbed causing the surface tension of the HFC rich phase to decrease. Consequently, the aneotrope point can be defined as the state at which the surface activity of both molecules is identical, or the relative adsorption of one component versus the other at the interface becomes zero.

Assessment of Anticancer Properties of Argemone mexicana L. and Berberine: A Comparative Study.

Argemone mexicana L. has been used in traditional Mexican medicine. Among its bioactive constituents, berberine (BER) has garnered attention for its cytotoxic properties against different tumor cell lines. This study investigates the in vitro toxicity against HEP-G2 (human hepatocellular carcinoma) and murine lymphoma (L5178Y-R) cells using the MTT assay of the methanol extract (AmexM), sub-partitions of A. mexicana, and BER. Selectivity indices (SIs) were determined by comparing their cytotoxic effects on VERO (monkey kidney epithelial) and PBMC (human peripheral blood mononuclear) non-tumoral cells. Additionally, the anti-hemolytic effect of these treatments was assessed using the AAPH method. The treatment with the most promising activity against tumor cells and anti-hemolytic efficacy underwent further evaluation for toxicity in Artemia salina and antioxidant activities using DPPH, ABTS, and FRAP assays. BER demonstrated an IC50 = 56.86 µg/mL in HEP-G2 cells and IC50 < 5.0 µg/mL in L5178Y-R cells, with SI values of 15.97 and >5.40 in VERO and PBMC cells, respectively. No significant hemolytic effects were observed, although AmexM and BER exhibited the highest anti-hemolytic activity. BER also demonstrated superior antioxidant efficacy, with lower toxicity in A. salina nauplii compared to the control. Additionally, BER significantly attenuated nitric oxide production. This study highlights the antiproliferative effects of A. mexicana, particularly BER, against HEP-G2 and L5178Y-R tumor cell lines, along with its selectivity towards normal cells. Furthermore, its anti-hemolytic and antioxidant potentials were demonstrated, suggesting that BER is a promising candidate for potent chemotherapeutic agents.

Effect of immobilized amines on the sorption properties of solid materials: impregnation versus grafting.

The underlying mechanism of the adsorption process in functionalized materials is not yet fully understood. This incomplete understanding limits the possibility of designing optimal adsorbent materials for different applications. Hence, the availability of complementary methods to advance this field is of great interest. We present here results concerning the adsorption of CO(2) in amine-functionalized silica materials by Monte Carlo simulations, providing new insights into the capture process. Two different mechanisms of functionalization are compared: impregnation (a physical mixture of the amine and the support) and grafting (a chemical bond is formed between the amine and the support). We evaluate in this work a model of MCM-41 for N(2) and CO(2) adsorption with varying degrees of density of the functionalized chains. The results indicate that the mobility of the impregnated chains allows the creation of a network of microcavities, which enhance the low-pressure adsorption capabilities of these materials. Molecular simulations allow us to study in detail the conformational changes in the functionalized chains during the adsorption process. Materials functionalized densely by grafting undergo a change in the preferential orientation of the chains, which allows the adsorption of additional molecules close to the surface of the support. The adsorption of gas molecules close to the pore surface is usually the most energetically favorable configuration; however, for densely grafted materials the adsorption close to the surface occurs only at pressures large enough to provide energy to displace the functionalized chains.

Exploring the Potential of Hierarchical Zeolite-Templated Carbon Materials for High-Performance Li-O2 Batteries: Insights from Molecular Simulations.

The commercialization of ultrahigh capacity lithium-oxygen (Li-O2) batteries is highly dependent on the cathode architecture, and a better understanding of its role in species transport and solid discharge product (i.e., Li2O2) formation is critical to improving the discharge capacity. Tailoring the pore size distribution in the cathode structure can enhance the ion mobility and increase the number of reaction sites to improve the formation of solid Li2O2. In this work, the potential of hierarchical zeolite-templated carbon (ZTC) structures as novel electrodes for Li-O2 batteries was investigated by using reactive force field molecular dynamics simulation (reaxFF-MD). Initially, 47 microporous zeolite-templated carbon morphologies were screened based on microporosity and specific area. Among them, four structures (i.e., RHO-, BEA-, MFI-, and FAU-ZTCs) were selected for further investigation including hierarchical features in their structures. Discharge product cluster analysis, self-diffusivities, and density number profiles of Li+, O2, and dimethyl sulfoxide (DMSO) electrolyte were obtained to find that the RHO-type ZTC exhibited enhanced mass transfer compared to conventional microporous ZTC (approximately 31% for O2, 44% for Li+, and 91% for DMSO) electrodes. This is due to the promoted formation of small-sized product clusters, creating more accessible sites for oxygen reduction reaction and mass transport. These findings indicate how hierarchical ZTC electrodes with micro- and mesopores can enhance the discharge performance of aprotic Li-O2 batteries, providing molecular insights into the underlying phenomena.

Survival estimates of childhood malignancies treated at the Mexican telethon pediatric oncology hospital.

BACKGROUND: Pediatric cancer incidence in Mexico is ~160/million/year with leukemias making 49.8% of the cases. While survival rates have been reported in various Mexican studies, no data is available from the Telethon Pediatric Oncology Hospital-HITO, a nonprofit private institution specialized exclusively in comprehensive pediatric oncology care in the country that closely follows high-income countries' advanced standards of cancer care. AIM: To determine overall survival (OS) and relapse-free survival (RFS) in patients treated at HITO between December 2013 and February 2018. METHODS AND RESULTS: Secondary analysis of data extracted from medical records. It included 286 children aged 0-17 years diagnosed with various cancers grouped into three categories based on location: (1) Acute lymphoblastic leukemia (ALL), (2) tumors within the central nervous system (TWCNS), and (3) tumors outside the CNS (TOCNS). OS and RFS rates for patients who completed 1 (n = 230) and 3 (n = 132) years of follow-up after admission were computed by sex, age, and cancer location, and separately for a subsample (1-year = 191, 3-years = 110) who fulfilled the HITO criteria (no prior treatment, underwent surgery/chemotherapy when indicated, and initiated therapy). TOCNS accounted for 45.1%, but ALL was the most frequent single diagnosis with 28%. Three-year OS for patients with ALL, TWCNS, and TOCNS who fulfilled the HITO criteria were 91.9%, 86.7%, and 79.3%, respectively; for 3-year RFS these were 89.2%, 60%, and 72.4%. Boys showed slightly higher OS and RFS, but no major differences or trends were seen by age group. CONCLUSION: This study sets a relevant reference in terms of survival and relapse for children with cancer in Mexico treated at a private oncology center that uses a comprehensive and integrated therapeutic model.

Searching for Sustainable Refrigerants by Bridging Molecular Modeling with Machine Learning.

We present here a novel integrated approach employing machine learning algorithms for predicting thermophysical properties of fluids. The approach allows obtaining molecular parameters to be used in the polar soft-statistical associating fluid theory (SAFT) equation of state using molecular descriptors obtained from the conductor-like screening model for real solvents (COSMO-RS). The procedure is used for modeling 18 refrigerants including hydrofluorocarbons, hydrofluoroolefins, and hydrochlorofluoroolefins. The training dataset included six inputs obtained from COSMO-RS and five outputs from polar soft-SAFT parameters, with the accurate algorithm training ensured by its high statistical accuracy. The predicted molecular parameters were used in polar soft-SAFT for evaluating the thermophysical properties of the refrigerants such as density, vapor pressure, heat capacity, enthalpy of vaporization, and speed of sound. Predictions provided a good level of accuracy (AADs = 1.3-10.5%) compared to experimental data, and within a similar level of accuracy using parameters obtained from standard fitting procedures. Moreover, the predicted parameters provided a comparable level of predictive accuracy to parameters obtained from standard procedure when extended to modeling selected binary mixtures. The proposed approach enables bridging the gap in the data of thermodynamic properties of low global warming potential refrigerants, which hinders their technical evaluation and hence their final application.

Adhesion and Cohesion of Silica Surfaces with Quartz Cement: A Molecular Simulations Study.

This study focuses on developing an adhesive and cohesive molecular modeling approach to study the properties of silica surfaces and quartz cement interfaces. Atomic models were created based on reported silica surface configurations and quartz cement. For the first time, molecular dynamics (MD) simulations were conducted to investigate the cohesion and adhesion properties by predicting the interaction energy and the adhesion pressure at the cement and silica surface interface. Results show that the adhesion pressure depends on the area density (per nm2) and degree of ionization, and van der Waals forces are the major contributor to the interactions between the cement and silica surfaces. Moreover, it is shown that adhesion pressure could be the actual rock failure mechanism in contrast to the reported literature which considers cohesion as the failure mechanism. The bonding energy factors for both "dry" and "wet" conditions were used to predict the water effect on the adhesion pressure at the cement-surface interface, revealing that H2O can cause a significant reduction in adhesion pressure. In addition, relating the adhesion pressure to the dimensionless area ratio of the cement to silica surfaces resulted in a good correlation that could be used to distribute the adhesion pressure in a rock system based on the area of interactions between the cement and the surface. This study shows that MD simulations can be used to understand the chemomechanics relationship fundamental of cement-surfaces of a reservoir rock at a molecular/atomic level and to predict the rock mechanical failure for sandstones, limestones, and shales.