Attention-based solubility prediction of polysulfide and electrolyte analysis for lithium-sulfur batteries.

During the continuous charge and discharge process in lithium-sulfur batteries, one of the next-generation batteries, polysulfides are generated in the battery's electrolyte, and impact its performance in terms of power and capacity by involving the process. The amount of polysulfides in the electrolyte could be estimated by the change of the Gibbs free energy of the electrolyte, [Formula: see text] in the presence of polysulfide. However, obtaining [Formula: see text] of the diverse mixtures of components in the electrolyte is a complex and expensive task that shows itself as a bottleneck in optimization of electrolytes. In this work, we present a machine-learning approach for predicting [Formula: see text] of electrolytes. The proposed architecture utilizes (1) an attention-based model (Attentive FP), a contrastive learning model (MolCLR) or morgan fingerprints to represent chemical components, and (2) transformers to account for the interactions between chemicals in the electrolyte. This architecture was not only capable of predicting electrolyte properties, including those of chemicals not used during training, but also providing insights into chemical interactions within electrolytes. It revealed that interactions with other chemicals relate to the logP and molecular weight of the chemicals.

Hydration and Mechanical Properties of High-Volume Fly Ash Concrete with Nano-Silica and Silica Fume.

This study investigated the effects of nano-silica (NS) and silica fume (SF) on the hydration reaction of high-volume fly ash cement (HVFC) composites. In order to solve the dispersibility problem caused by the agglomeration of NS powder, NS and NSF solutions were prepared. NS content and SF content were used as main variables, and an HVFC paste was prepared in which 50% of the cement volume was replaced by fly ash (FA). The initial heat of hydration was measured using isothermal calorimetry to analyze the effects of NS and SF on the initial hydration properties of the HVFC. In addition, the compressive strength was analyzed by age. The refinement of the pore structure by the nanomaterial was analyzed using mercury intrusion porosimetry (MIP). The results show that the addition of NS and SF shortened the setting time and induction period by accelerating the initial hydration reaction of HVFC composites and improved the compressive strength during the initial stage of hydration. In addition, the micropore structure was improved by the pozzolanic reaction of NS and SF, thereby increasing the compressive strength during the middle stage of hydration.

Qualitative Determination of Polysulfide Species in a Lithium-Sulfur Battery by HR-LC-APCI-MSn with One-Step Derivatization.

Lithium-Sulfur (Li-S) batteries are one of the most promising next-generation batteries due to their ultrahigh energy density up to 500 W h kg-1. However, despite the steady progress during the last several decades, there have been significant challenges for practical applications and commercialization. One of the major issues is controlling the lithium polysulfide (LiPS) shuttling process, which causes premature cell failure. To better understand the mechanism of the LiPS shuttling chemistry, a qualitative and quantitative analysis on polysulfide species in Li-S cell has profound significance for realizing highly efficient sulfur electrochemistry. Here we report a qualitative determination of the derivatized polysulfides in the electrolyte of a custom-made Li-S pouch cell with a high-resolution liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry method for the first time. The ionization efficiency of the methylated polysulfides was affected by the tune parameters such as the corona discharge current, the vaporizer temperature, and the source capillary temperature. It was found that the source capillary temperature was the dominant parameter to increase the peak intensity of CH3S7- ion, which was the smallest peak in the spectrum. An unusual and unique ionization pattern for methylated polysulfides detected in atmospheric pressure chemical ionization negative mode was elucidated by using first-principles calculations.

Self-Healing Products of Cement Pastes with Supplementary Cementitious Materials, Calcium Sulfoaluminate and Crystalline Admixtures.

The phase composition of self-healing products generated in cracks affects self-healing performance. This study investigated the self-healing products of cementitious materials using supplementary cementitious materials (SCMs), a calcium sulfoaluminate (CSA) expansion agent, and crystalline additives (CAs). Ground-granulated blast-furnace slag (GGBFS), fly ash (FA), and silica fume (SF) were used as SCMs, and anhydrite, Na2SO4, Na2CO3, and MgCO3 were used as crystalline additives (CAs). An artificial crack method was used to collect the self-healing products in the crack of the paste. The phase composition of the self-healing products was analyzed through X-ray diffraction (XRD)/Rietveld refinements and thermogravimetry/differential thermogravimetry (TG/DTG) analysis, and their morphology and ion concentration were examined through scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). From the results, the main compound of self-healing products was found to be calcite. GGBFS and FA decreased the content of portlandite, and the use of CAs led to the formation of alkali sulfate and alkali carbonate. The SEM-EDS analysis results showed that when GGBFS and FA were used, a large proportion of the self-healing products contained C-S-H and C-A-H, and the use of CSA led to the formation of monosulfate and ettringite.

Effect of Clinker Binder and Aggregates on Autogenous Healing in Post-Crack Flexural Behavior of Concrete Members.

Crack healing has been studied extensively to protect reinforced concrete structures from the ingress of harmful ions. Research examining the regain in the mechanical properties of self-healing composites has focused mostly on the computation of the healing ratio based on the measurement of the tensile and compressive strengths but with poor regard for the flexural performance. However, the regain in the flexural performance should also be investigated for design purposes. The present study performs flexural testing on reinforced concrete members using crushed clinker binder and aggregates as well as crystalline admixtures as healing agents. Healing ratios of 100% for crack widths smaller than 200 µm and 85% to 90% for crack widths of 250 µm were observed according to the admixing of clinker binder and aggregates. Water flow test showed that the members replacing binder by 100% of clinker achieved the best crack healing performance. The crack healing property of concrete improved to some extent the rebar yield load, the members' ultimate load and energy absorption capacity and ductility index. The crack distribution density from the observed crack patterns confirmed the crack healing effect provided by clinker powder. The fine grain size of clinker made it possible to replace fine aggregates and longer healing time increased the crack healing effect.

Pore Structure Characteristics of Foam Composite with Active Carbon.

Characterization of porous materials is essential for predicting and modeling their adsorption performance, strength, and durability. However, studies on the optimization of the pore structure to efficiently remove pollutants in the atmosphere by physical adsorption of construction materials have been insufficient. This study investigated the pore structure characteristics of foam composites. Porous foam composites were fabricated using foam composite with high porosity, open pores, and palm shell active carbon with micropores. The content was substituted 5%, 10%, 15%, and 20% by volume of cement. From the measured nitrogen adsorption isotherm, the pore structure of the foam composite was analyzed using the Brunauer-Emmett-Teller (BET) theory, Barrett-Joyner-Halenda (BJH) analysis, and Harkins-jura adsorption isotherms. From the analysis results, it was found that activated carbon increases the specific surface area and micropore volume of the foam composite. The specific surface area and micropore volume of the foam composite containing 15% activated carbon were 106.48 m2/g and 29.80 cm3/g, respectively, which were the highest values obtained in this study. A foam composite with a high micropore volume was found to be effective for the adsorption of air pollutants.

Li-diffusion at the interface between Li-metal and [Pyr14][TFSI]-ionic liquid: Ab initio molecular dynamics simulations.

We previously reported comprehensive density functional theory-molecular dynamics (DFT-MD) at 400 K to determine the composition and structure of the solid electrolyte interface (SEI) between a Li anode and [Pyr14][TFSI] ionic liquid. In this paper, we examined diffusion rates in both the Li-electrode region and SEI compact layer in smaller 83Li/2[TFSI] and larger 164Li/4[TFSI] systems. At 400 K, the Li-diffusion constant in the Li-region is 1.35 × 10-10 m2/s for 83Li/2[TFSI] and 5.64 × 10-10 m2/s for 164Li/4[TFSI], while for the SEI it is 0.33 × 10-10 m2/s and 0.22 × 10-10 m2/s, thus about one order slower in the SEI compared to the Li-region. This Li-diffusion is dominated by hopping from the neighbor shell of one F or O to the neighbor shell of another. Comparing the Li-diffusion at different temperatures, we find that the activation energy is 0.03 and 0.11 eV for the Li-region in the smaller and larger systems, respectively, while for the SEI it is 0.09 and 0.06 eV.

Interface Structure in Li-Metal/[Pyr14][TFSI]-Ionic Liquid System from ab Initio Molecular Dynamics Simulations.

Ionic liquids (ILs) are promising materials for application in a new generation of Li batteries. They can be used as electrolyte or interlayer or incorporated into other materials. ILs have the ability to form a stable solid electrochemical interface (SEI), which plays an important role in protecting the Li-based electrode from oxidation and the electrolyte from extensive decomposition. Experimentally, it is hardly possible to elicit fine details of the SEI structure. To remedy this situation, we have performed a comprehensive computational study (density functional theory-based molecular dynamics) to determine the composition and structure of the SEI compact layer formed between the Li anode and [Pyr14][TFSI] IL. We found that the [TFSI] anions quickly reacted with Li and decomposed, unlike the [Pyr14] cations which remained stable. The obtained SEI compact layer structure is nonhomogeneous and consists of the atomized S, N, O, F, and C anions oxidized by Li atoms.

Characteristics of South Korean Patients with Hereditary Transthyretin Amyloidosis.

BACKGROUND AND PURPOSE: This retrospective cross-sectional study included 18 patients from unrelated families harboring mutations of the transthyretin gene (TTR), and analyzed their characteristics and geographical distribution in South Korea. METHODS: The included patients had a diagnosis of systemic amyloidosis, clinical symptoms, such as amyloid neuropathy or cardiomyopathy, and confirmation of a TTR gene mutation using genetic analysis recorded between April 1995 and November 2014. RESULTS: The mean age at disease onset was 49.6 years, and the mean disease duration from symptom onset to diagnosis was 3.67 years. Fifteen of the 18 patients were classified as mixed phenotype, 2 as the neurological phenotype, and only 1 patient as the cardiac phenotype. The most-common mutation pattern in South Korea was Asp38Ala, which was detected in eight patients. Thirteen patients reported their family hometowns, and five of the eight harboring the Asp38Ala mutation were from the Gyeongsang province in southeast Korea. The other eight patients exhibited a widespread geographical distribution. A particularly noteworthy finding was that the valine at position 30 (Val30Met) mutation, which was previously reported as the most-common TTR mutation worldwide and also the most common in the Japanese population, was not detected in the present South Korean patients. CONCLUSIONS: South Korean patients with hereditary TTR amyloidosis exhibited heterogeneous TTR genotypes and clinical phenotypes. The findings of this study suggest that the distribution of TTR amyloidosis in South Korea is due to de novo mutations and/or related to the other countries in East Asia.

Flexural Behavior of HPFRCC Members with Inhomogeneous Material Properties.

In this paper, the flexural behavior of High-performance Fiber-Reinforced Cementitious Composite (HPFRCC) has been investigated, especially focusing on the localization of cracks, which significantly governs the flexural behavior of HPFRCC members. From four points bending tests with HPFRCC members, it was observed that almost evenly distributed cracks formed gradually, followed by a localized crack that determined the failure of the members. In order to investigate the effect of a localized crack on the flexural behavior of HPFRCC members, an analytical procedure has been developed with the consideration of intrinsic inhomogeneous material properties of HPFRCC such as cracking and ultimate tensile strengths. From the comparison, while the predictions with homogeneous material properties overestimated flexural strength and ductility of HPFRCC members, it was found that the analysis results considering localization effect with inhomogeneous material properties showed good agreement with the test results, not only the flexural strength and ductility but also the crack widths. The test results and the developed analysis procedure presented in this paper can be usefully applied for the prediction of flexural behaviors of HPFRCC members by considering the effect of localized cracking behavior.

Comparison of in vitro and in vivo phototoxicity tests with S-(-)-10,11-dihydroxyfarnesic acid methyl ester produced by Beauveria bassiana KACC46831.

Beauveria bassiana is a fungi that is well-known for demonstrating a resistance to environmental change. To confirm whether S-(-)-10,11-dihydroxyfarnesic acid methyl ester (DHFAME) produced by Beauveria bassiana KACC46831 causes phototoxicity when used for cosmetic purposes due to its anti-tyrosinase activity, we conducted in vitro and in vivo phototoxicity tests. There were no significant changes or damage observed in the compound-treated group with regards to skin phototoxicity, while 8-methoxypsoralen, which served as a positive control, induced toxic effects. The in vitro 3T3 neutral red uptake assay, an alternative assessment, was used for further confirmation of the phototoxicity. The results showed that DHFAME did not exhibit phototoxicity at the designated concentrations, with or without UV irradiation in the 3T3 cells. These results indicated that the methyl ester produced by Beauveria bassiana KACC46831 does not induce phototoxicity in the skin. Therefore, the results of the present study indicate that DHFAME shows potential for use as a cosmetic ingredient that does not cause skin phototoxicity.

Heat shock protein 70 (HSP70) expression is associated with poor prognosis in intestinal type gastric cancer.

Heat shock protein 70 (HSP70) is a molecular chaperone which plays an important role in cellular protection against various stressful stimuli and in the regulation of cellular growth and apoptosis. This study was conducted in gastric carcinoma (GC) to assess correlations of HSP70 expression with clinicopathological parameters and overall survival (OS). Tissue microarray blocks were constructed from 172 GCs and immunohistochemically stained for HSP70. Low HSP70 expression was found in 122 GCs (71 %), whereas 50 (29 %) had high expression. HSP70 expression was higher in tumours in the cardia (p = 0.008), with non-signet ring cell histology (p < 0.001), of intestinal type (p = 0.045) and of higher pathological T stage (p = 0.026). When considering the cohort as a whole, HSP70 expression did not correlate with OS (p = 0.092). In intestinal type carcinomas, however, high HSP70 expression significantly correlated with worse OS (p = 0.034). These results suggest that HSP70 expression might be an unfavourable prognostic factor in patients with GC, especially of intestinal type.

Photovoltaic performance of dye-sensitized solar cell low temperature growth of ZnO nanorods using chemical bath deposition.

Nanostructured ZnO photoelectrodes were synthesized on fluorine-doped tin oxide (FTO) glass substrates that were spin-coated with a sol-gel based ZnO seed layer via a chemical bath deposition (CBD) method at varying times of 1, 2, 4, and 8 h. Then, TiO2 nanoparticulate electrodes were prepared on ZnO nanorods using the doctor blade technique. The uniformly grown ZnO nanorod layer had a length of approximately 710 nm on the FTO glass substrate with wurtzite structures which was confirmed through X-ray diffraction patterns. The length and diameter of the ZnO nanorods increased with an increase in the deposition time. The DSSCs fabricated with TiO2 nanoparticulate/grown ZnO nanorods and grown for 8 h showed the maximum efficiency (5.51%) with a short circuit current density (J(sc)) of 12.21 mA/cm2 and an open circuit voltage (V(oc)) of 0.70 at 100 mW/cm2 light intensity.

[100] Directed Cu-doped h-CoO nanorods: elucidation of the growth mechanism and application to lithium-ion batteries.

Thermal decomposition of Co(acac)(3) and Cu(acac)(2) in benzylamine leads to the formation of [100] directed Cu-doped h-CoO nanorods, which are very stable in an aqueous solution. The formation mechanism of the [100] directed Cu-doped h-CoO nanorods is fully elucidated by using first-principles calculations, demonstrating that Cu-doping not only changes the growth direction but also enhances the stability of the nanorods significantly. Evaluation of the electrochemical performance of Cu-doped h-CoO nanorods shows high initial Coulombic efficiency and ultrahigh capacity with excellent cycling performance, indicating their suitability as an anode material for next generation lithium-ion batteries.

Comparison of the Sequential Organ Failure Assessment, Acute Physiology and Chronic Health Evaluation II scoring system, and Trauma and Injury Severity Score method for predicting the outcomes of intensive care unit trauma patients.

PURPOSE: The aim of this study was to assess the ability of the Sequential Organ Failure Assessment (SOFA), Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system, and Trauma and Injury Severity Score (TRISS) method to predict group mortality for intensive care unit (ICU) trauma patients. METHODS: The medical records of 706 consecutive major trauma patients admitted to the ICU of Samsung Changwon Hospital from May 2006 to April 2010 were retrospectively examined. The SOFA and the APACHE II scores were calculated based on data from the first 24 hours of ICU admission, and the TRISS was calculated using initial laboratory data from the emergency department and operative data. The probability of death was calculated for each patient based on the SOFA score, APACHE II score, and TRISS equations. The ability to predict group mortality for the SOFA score, APACHE II score, and TRISS method was assessed by using 2-by-2 decision matrices and receiver operating characteristic curve analysis and calibration analysis. RESULTS: In 2-by-2 decision matrices with a decision criterion of 0.5, the sensitivities, specificities, and accuracies were 74.1%, 97.1%, and 92.4%, respectively, for the SOFA score; 58.5%, 99.6%, and 91.1%, respectively, for the APACHE II scoring system; and 52.4%, 94.8%, and 86.0%, respectively, for the TRISS method. In the receiver operating characteristic curve analysis, the areas under the curve for the SOFA score, APACHE II scoring system, and TRISS method were 0.953, 0.950, and 0.922, respectively. CONCLUSION: The results from the present study showed that the SOFA score was not different from APACHE II scoring system and TRISS in predicting the outcomes for ICU trauma patients. However, the method for calculating SOFA scores is easier and simpler than APACHE II and TRISS.

A radical polymer as a two-dimensional organic half metal.

Given that half-metals are promising futuristic materials for spintronics, organic materials showing half-metal character are highly desirable for spintronic devices, not only owing to their weak spin-orbit and hyperfine interactions, but also their light and flexible properties. We predict that a two-dimensional organic 2,4,6-tri-(1,3,5-triazinyl)methyl radical polymer has half-metallic properties as well as a spontaneous magnetic ordering at ambient temperature. The quantum transmission is studied based on the nonequilibrium Green function theory coupled with density functional theory. The half-metallic property in the triazine-based polymer depends mainly on the nature of the p-band in contrast to of conventional half metals in which the nature of the d-band is more important.

Comparison of cationic, anionic and neutral hydrogen bonded dimers.

Short Strong Hydrogen Bonds (SSHBs) play an important role in many fields of physics, chemistry and biology. Since it is known that SSHBs exist in many biological systems, the role of hydrogen bonding motifs has been particularly interesting in enzyme catalysis, bio-metabolism, protein folding and proton transport phenomena. To explore the characteristic features of neutral, anionic and cationic hydrogen bonds, we have carried out theoretical studies of diverse homogeneous and heterogeneous hydrogen bonded dimers including water, peroxides, alcohols, ethers, aldehydes, ketones, carboxylic acids, anhydrides, and nitriles. Geometry optimization and harmonic frequency calculations are performed at the levels of Density Functional Theory (DFT) and Møller-Plesset second order perturbation (MP2) theory. First principles Car-Parrinello molecular dynamics (CPMD) simulations are performed to obtain IR spectra derived from velocity- and dipole-autocorrelation functions. We find that the hydrogen bond energy is roughly inversely proportional to the fourth power of the r(O/N-H) distance. Namely, the polarization of the proton accepting O/N atom by the proton-donating H atom reflects most of the binding energy in these diverse cation/anion/neutral hydrogen bonds. The present study gives deeper insight into the nature of hydrogen-bonded dimers including SSHBs.

Application of quantum chemistry to nanotechnology: electron and spin transport in molecular devices.

Rapid progress of nanotechnology requires developing novel theoretical methods to explain complicated experimental results and predict new functions of nanodevices. Thus, for the last decade, one of the challenging works of quantum chemistry is to understand the electron and spin transport phenomena in molecular devices. This critical review provides an extensive survey of on-going research and its current status in molecular electronics with the focus on theoretical applications to diverse types of devices along with a brief introduction of theoretical methods and its practical implementation scheme. The topics cover diverse molecular devices such as molecular wires, rectifiers, field effect transistors, electrical and optical switching devices, nanosensors, spin-valve devices, negative differential resistance devices and inelastic electron tunnelling spectroscopy. The limitations of the presented method and the possible approaches to overcome the limitations are addressed (183 references).

Neutral and Anionic Gold Decamers: Planar Structure with Unusual Spatial Charge-Spin Separation.

We have investigated the issue of two-dimensional (2D) versus three-dimensional (3D) structures for neutral-state Au10 and clarified the lowest-energy structure among a few 2D Au10(-) isomers. Though almost all previous works were based on density functional theory (DFT), we here carried out not only extensive DFT calculations but also high levels of ab initio calculations of Möller-Plesset second order perturbation theory (MP2), and coupled cluster theory with single and double excitations (CCSD) including perturbative triple excitations [CCSD(T)]. While DFT favors 2D structures, MP2 and CCSD(T) favor 3D structures for moderate-sized basis sets. However, we note that the basis-set superposition error (BSSE) corrections make the ab intio results favor 2D structures too. The near-degeneracy (driven by relativistic effects) of 5d and 6s orbitals of gold helps stabilize acute apex gold atoms, resulting in 2D structures. The planar triangular structures of a local minimum Au10 (triplet) and the global minimum Au10(-) show remarkable spatial charge-spin separation due to their singly occupied molecular orbital(s). By the same reason, Au10(-) shows much larger vertical detachment energy than other even-numbered gold cluster anions.

Increased tissue transglutaminase expression in human atherosclerotic coronary arteries.

BACKGROUND AND OBJECTIVE: Transglutaminase 2 (TGase 2) is a calcium-dependent cross-linking enzyme that catalyzes a covalent iso-peptide bond between two proteins. Interestingly, this catalysis can activate the nuclear factor-kappaB (NF-kappaB) through the polymerization of the inhibitory protein of NF-kappaB (I-kappaB). The objective of the present study was to investigate the expression of TGase 2 in the human atherosclerotic human coronary artery, and the possible roles of TGase 2 in NF-kappaB activation. METHODS AND RESULTS: We explored whether expressions of TGase 2 and NF-kappaB are associated in atherosclerosis. Using human samples, we found that TGase 2 was markedly higher than normal in the neointimal tissue of atherosclerotic coronary arteries with atherosclerosis progression. TGase 2 activity was also increased approximately two-fold in the atherosclerotic vascular wall. In immunofluorescence analysis, NF-kappaB, COX-2, and TNF-alpha were co-localized at TGase 2-positive neointimal smooth muscle cells. A promoter assay test showed that NF-kappaB activity increased in both the human monocyte and human breast carcinoma cell by TGase 2, and that TGase 2-mediated NF-kappaB activation was reversed by TGase 2 siRNA. CONCLUSION: According to these results, we suggest that TGase 2 may function as an activator in the NF-kappaB pathway; this effect may occur in the atherosclerotic vessel wall.