Effect of Condensed Water at an Alumina/Epoxy Resin Interface on Curing Reaction

The adhesion of epoxy adhesives to aluminum materials is an important issue in assembling parts for lightweight mobility. Aluminum surfaces typically possess an oxide layer, which readily adsorbs water. In this study, the aggregation states of water and its effect on the curing reaction were examined by placing a water layer between an amorphous alumina surface and a mixture of epoxy and amine components. This study used molecular dynamics simulations and density functional theory calculations. Before the reaction, water molecules strongly adsorbed onto the alumina surface, aggregating excess water. Some water diffused into the epoxy/amine mixture, accelerating the diffusion of unreacted substances. This led to faster reaction kinetics, particularly in proximity to the alumina surface. The adsorption of water molecules onto the alumina surface and the aggregation of excess water were similarly observed even after the curing process. Subsequently, the interaction between the alumina surface and various functional groups of the epoxy/amine mixture was evaluated before and after the reaction. Epoxy monomers had little interaction with the alumina surface before the reaction, whereas hydroxy groups formed by the ring-opening reaction of epoxy groups exhibited notable interaction. Conversely, sulfonyl and amino groups in amine compounds formed hydrogen bonds with OH groups on the alumina surface before the reaction. However, after the reaction, amino groups weakened their interaction with the alumina OH groups as they transformed from primary to tertiary during the curing reaction. Both epoxy and amine monomers/fragments similarly interacted with water molecules, both before and after the reaction. The insights gained from this study are expected to contribute to a better understanding of the impact of moisture absorption on the application of epoxy resins.

Electronic Interaction of Epoxy Resin with Copper at the Adhered Interface

A better understanding of the aggregation states of adhesive molecules in the interfacial region with an adherend is crucial for controlling the adhesion strength and is of great inherent academic interest. The adhesion mechanism has been described through four theories: adsorption, mechanical, diffusion, and electronic. While interfacial characterization techniques have been developed to validate the aforementioned theories, that related to the electronic theory has not yet been thoroughly studied. We here directly detected the electronic interaction between a commonly used thermosetting adhesive, cured epoxy of diglycidyl ether of bisphenol A (DGEBA) and 4,4'-diaminodiphenylmethane (DDM), and copper (Cu). This study used a combination of density functional theory (DFT) calculations and femtosecond transient absorption spectroscopic (TAS) measurements as this epoxy adhesive-Cu pairing is extensively used in electronic device packaging. The DFT calculations predicted that π electrons in a DDM molecule adsorbed onto the Cu surface flowed out onto the Cu surface, resulting in a positive charge on the DDM. TAS measurements for the Cu/epoxy multilayer film, a model sample containing many metal/adhesive interfaces, revealed that the electronic states of excited DDM moieties at the Cu interface were different from those in the bulk region. These results were in good accordance with the prediction by DFT calculations. Thus, it can be concluded that TAS is applicable to characterize the electronic interaction of adhesives with metal adherends in a nondestructive manner.

Molecular Understanding of the Distinction between Adhesive Failure and Cohesive Failure in Adhesive Bonds with Epoxy Resin Adhesives

In the development of adhesives, an understanding of the fracture behavior of the bonded joints is inevitable. Two typical failure modes are known: adhesive failure and cohesive failure. However, a molecular understanding of the cohesive failure process is not as advanced as that of the adhesive failure process. In this study, research was developed to establish a molecular understanding of cohesive failure using the example of a system in which epoxy resin is bonded to a hydroxyl-terminated self-assembled monolayer (SAM) surface. Adhesive failure was modeled as a process in which an epoxy molecule is pulled away from the SAM surface. Cohesive failure, on the other hand, was modeled as the process of an epoxy molecule separating from another epoxy molecule on the SAM surface or breaking of a covalent bond within the epoxy resin. The results of the simulations based on the models described above showed that the results of the calculations using the model of cohesive failure based on the breakdown of intermolecular interactions agreed well with the experimental results in the literature. Therefore, it was suggested that the cohesive failure of epoxy resin adhesives is most likely due to the breakdown of intermolecular interactions between adhesive molecules. We further analyzed the interactions at the adhesive failure and cohesive failure interfaces and found that the interactions at the cohesive failure interface are mainly accounted for by dispersion forces, whereas the interactions at the adhesive failure interface involve not only dispersion forces but also various chemical interactions, including hydrogen bonds. The selectivity between adhesive failure and cohesive failure was explained by the fact that varying the functional group density affected the chemical interactions but not the dispersion forces.

Clinical and ultrasound features of difficult-to-treat rheumatoid arthritis: A multicenter RA ultrasound cohort study

OBJECTIVE

The optimal strategy for difficult-to-treat (D2T) rheumatoid arthritis (RA) has not been identified, and the ultrasound characteristics of D2T RA have not been reported. We investigated the clinical characteristics and factors contributing to the outcome in D2T RA in a multicentre RA ultrasound observational cohort.

METHOD

We reviewed 307 Japanese patients diagnosed with RA who underwent treatment with biological and targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs). We compared the differences in patient characteristics between the D2T RA and non-D2T RA groups. We examined the factors contributing to a good response [defined as b/tsDMARD continuation and Clinical Disease Activity Index (CDAI) ≤ 10 at 12 months] in the D2T RA patient group.

RESULTS

Forty-three patients (14%) were categorized as D2T RA and the remaining 264 (86%) as non-D2T RA at baseline. The grey-scale (GS) score, disease duration, and CDAI at the initiation of treatment were significantly higher in the D2T RA group than in the non-D2T RA group. In contrast, the power Doppler (PD) score was not significantly different between the two groups. Of the 43 D2T RA patients, 20 achieved a good response. The introduction of CTLA4-Ig (n = 5) was significantly associated with a good response in analysis based on inverse probability weighting with propensity score. GS and PD scores at baseline were not significantly associated with therapeutic response at 12 months in D2T RA patients.

CONCLUSIONS

Patients with D2T RA had high clinical and ultrasound activity and poor responses to treatment with b/tsDMARDs. CTLA4-Ig was associated with a good response at 12 months in D2T RA patients.

An immunocytokine consisting of a TNFR2 agonist and TNFR2 scFv enhances the expansion of regulatory T cells through TNFR2 clustering

Regulatory T cells (Tregs) are lymphocytes that play a central role in peripheral immune tolerance. Tregs are promising targets for the prevention and suppression of autoimmune diseases, allergies, and graft-versus-host disease, and treatments aimed at regulating their functions are being developed. In this study, we created a new modality consisting of a protein molecule that suppressed excessive immune responses by effectively and preferentially expanding Tregs. Recent studies reported that tumor necrosis factor receptor type 2 (TNFR2) expressed on Tregs is involved in the proliferation and activation of Tregs. Therefore, we created a functional immunocytokine, named TNFR2-ICK-Ig, consisting of a fusion protein of an anti-TNFR2 single-chain Fv (scFv) and a TNFR2 agonist TNF-α mutant protein, as a new modality that strongly enhances TNFR2 signaling. The formation of agonist-receptor multimerization (TNFR2 cluster) is effective for the induction of a strong TNFR2 signal, similar to the TNFR2 signaling mechanism exhibited by membrane-bound TNF. TNFR2-ICK-Ig improved the TNFR2 signaling activity and promoted TNFR2 cluster formation compared to a TNFR2 agonist TNF-α mutant protein that did not have an immunocytokine structure. Furthermore, the Treg expansion efficiency was enhanced. TNFR2-ICK-Ig promotes its effects via scFv, which crosslinks receptors whereas the agonists transmit stimulatory signals. Therefore, this novel molecule expands Tregs via strong TNFR2 signaling by the formation of TNFR2 clustering.

Elucidating the Effects of Chemisorbed Water Molecules on the Adhesive Interactions of Epoxy Resin to γ-Alumina Surfaces

The adhesion mechanism of epoxy resin to the γ-alumina (110) surface was investigated using first-principles density functional theory (DFT). Aluminum materials are lightweight and are used in a wide range of industrial fields. Its surface is oxidized to alumina, and the stable surface is known as the γ-alumina (110) surface. The coverage of hydroxy groups by chemisorbed water molecules on this surface varied depending on the pretreatment temperature. In this study, we investigated the adhesive interactions of epoxy resin on four alumina surfaces with different densities of surface hydroxy groups (0, 3, 6, and 9 OH/nm2) and have discussed their effects. At each interface, the energy curves of the vertically displaced epoxy resin were calculated and the adhesive forces were estimated by differentiating these curves. As the coverage of the surface hydroxy groups increased from 0 to 6 OH/nm2, the adhesive strength gradually decreased. However, the adhesive strength at 9 OH/nm2 was relatively large and almost equal to that at 3 OH/nm2. This inverse volcano-type behavior was analyzed via the decomposition of adhesive forces and the crystal orbital Hamilton population (COHP). The decomposition of adhesive forces into DFT and dispersion components revealed that the inverse volcano-type behavior is derived from the DFT component, and the interfacial interactions owing to the DFT component are accompanied by charge transfer. These were investigated using a COHP analysis, which revealed that this behavior was caused by changes in the activity of the aluminum atoms on the surface and surface reconstruction by chemisorbed water molecules. It is noteworthy that the adhesive strength for 9 OH/nm2 was only 6.9% lower than that for 0 OH/nm2 wherein the chemisorbed water molecules were completely removed from the surface. These results are expected to provide a guideline for the adhesion of epoxy resin to aluminum materials.

Hückel Molecular Orbital Analysis for Stability and Instability of Stacked Aromatic and Stacked Antiaromatic Systems

Face-to-face stacking of aromatic compounds leads to stacked antiaromaticity, while that of antiaromatic compounds leads to stacked aromaticity. This is a prediction with a long history; in the late 2000s, the prediction was confirmed by high-precision quantum chemical calculations, and finally, in 2016, a π-conjugated system with stacked aromaticity was synthesized. Several variations have since been reported, but essentially, they are all the same molecule. To realize stacked aromaticity in a completely new and different molecular system and to trigger an extension of the concept of stacked aromaticity, it is important to understand the origin of stacked aromaticity. The Hückel method, which has been successful in giving qualitatively correct results for π-conjugated systems despite its bold assumptions, is well suited for the analysis of stacked aromaticity. We use this method to model the face-to-face stacking systems of benzene and cyclobutadiene molecules and discuss their stacked antiaromaticity and stacked aromaticity on the basis of their π-electron energies. By further developing the discussion, we search for clues to realize stacked aromaticity in synthesizable molecular systems.

Efficacy of zinc acetate hydrate for hypozincemia in the elderly is influenced by the initial accumulated exposure dose after taking zinc acetate hydrate

This study aimed to determine the efficacy of zinc acetate hydrate (ZAH) for hypozincemia in elderly hospitalized patients with an accumulated exposure of < 1000 mg of ZAH and to explore the factors affecting the therapeutic efficacy of ZAH. Seventy-four patients (mean age, 82 years) were enrolled in this study. All patients (n = 74) had low serum zinc levels (< 80 μg/dL), and the mean serum zinc concentration before ZAH administration was 53.6±10.7 μg/dL. The median serum zinc level (μg/dL) elevated per tablet (25 mg) of ZAH was 1.26 μg/dL, and the patients were divided into two groups, the slightly increased (< 1.26) and significantly increased (≥ 1.26) groups, based on the median cutoff value for the median increase in serum zinc level. A significant difference was found between the slightly increased (0.63±0.35 μg/dL, n = 36) and significantly increased (2.37±0.95 μg/dL, n = 38) groups (p < 0.0001, Wilcoxon rank-sum test). Logistic regression analysis with the accumulated exposure dose of ZAH, sex, and body weight as multivariate variables showed a significant difference in the accumulated exposure dose (total number of tablets per 25 mg: odds ratio, 1.119; 95% confidence interval, 1.052???1.203; p = 0.0009). There was no effect of underlying disease or of diet or zinc-containing intravenous or enteral nutrition on serum zinc levels. These results suggest that at an accumulated exposure of < 1000 mg of ZAH, serum zinc levels tend to increase with smaller accumulated doses. Therefore, serum zinc concentrations should be measured at the accumulated exposure to 500-1000 mg after ZAH initiation for the treatment of zinc deficiency in elderly hospitalized patients.

Bivalent structure of a TNFR2-selective and agonistic TNF-α mutein Fc-fusion protein enhances the expansion activity of regulatory T cells

Recently, TNF receptor type 2 (TNFR2) signaling was found to be involved in the proliferation and activation of regulatory T cells (Tregs), a subpopulation of lymphocytes that suppress immune responses. Tregs mediate peripheral immune tolerance, and the disruption of their functions causes autoimmune diseases or allergy. Therefore, cell expanders or regulators of Tregs that control immunosuppressive activity can be used to treat these diseases. We focused on TNFR2, which is preferentially expressed on Tregs, and created tumor necrosis factor-α (TNF-α) muteins that selectively activate TNFR2 signaling in mice and humans, termed R2agoTNF and R2-7, respectively. In this study, we attempted to optimize the structure of muteins to enhance their TNFR2 agonistic activity and stability in vivo by IgG-Fc fusion following single-chain homo-trimerization. The fusion protein, scR2agoTNF-Fc, enhanced the expansion of CD4+CD25+ Tregs and CD4+Foxp3+ Tregs and contributed to their immunosuppressive activity ex vivo and in vivo in mice. The prophylactic administration of scR2agoTNF-Fc suppressed inflammation in contact hypersensitivity and arthritis mouse models. Furthermore, scR2-7-Fc preferentially expanded Tregs in human peripheral blood mononuclear cells via TNFR2. These TNFR2 agonist-Fc fusion proteins, which have bivalent structures, are novel Treg expanders.

Exploring Metal Nanocluster Catalysts for Ammonia Synthesis Using Informatics Methods: A Concerted Effort of Bayesian Optimization, Swarm Intelligence, and First-Principles Computation

This paper details the use of computational and informatics methods to design metal nanocluster catalysts for efficient ammonia synthesis. Three main problems are tackled: defining a measure of catalytic activity, choosing the best candidate from a large number of possibilities, and identifying the thermodynamically stable cluster catalyst structure. First-principles calculations, Bayesian optimization, and particle swarm optimization are used to obtain a Ti8 nanocluster as a catalyst candidate. The N2 adsorption structure on Ti8 indicates substantial activation of the N2 molecule, while the NH3 adsorption structure suggests that NH3 is likely to undergo easy desorption. The study also reveals several cluster catalyst candidates that break the general trade-off that surfaces that strongly adsorb reactants also strongly adsorb products.

Frontier Orbital Views of Stacked Aromaticity

Recent studies have theoretically and experimentally demonstrated that antiaromatic molecules with 4n π electrons exhibit stacked aromaticity according to π-π stacking when arranged in a face-to-face manner. However, the mechanism of its occurrence has not been clearly studied. In this study, we investigated the mechanism of stacked aromaticity using cyclobutadiene. When the antiaromatic molecules are stacked in a face-to-face manner, the orbital interactions between the degenerate singly occupied molecular orbitals (SOMOs) of the monomer unit cause a larger energy gap between the degenerate highest-occupied molecular orbitals (HOMOs) and the lowest-unoccupied molecular orbitals (LUMOs) of the dimer. However, the antiaromatic molecules are more stable in less symmetric conformations, mainly because of pseudo-Jahn-Teller distortions. In the case of cyclobutadiene, the two SOMOs of the monomer unit split into HOMO and LUMO because of the bond alternation. When the molecules are stacked in a face-to-face manner, the HOMO-LUMO gap of the dimer is smaller than that of the monomer due to the interactions between the HOMOs and LUMOs of the two monomer units. When the monomer units are within a specific distance of each other, the HOMO and LUMO of the dimer, which correspond to antibonding and bonding between the units, respectively, are interchanged. This alternation of molecular orbitals may result in an increase in the bond strength between the monomer units, exhibiting stacked aromaticity. We demonstrated that it is possible to control the distance exhibited by stacked aromaticity by engineering the HOMO-LUMO gap of the monomer units.

Transarterial ethiodised oil marking before CT-guided renal cryoablation: evaluation of tumour visibility in various renal cell carcinoma subtypes

AIM

To evaluate ethiodised oil retention of transarterial embolisation using ethiodised oil (ethiodised oil marking) before computed tomography (CT)-guided percutaneous cryoablation (PCA) according to renal cell carcinoma (RCC) subtype.

MATERIALS AND METHODS

Ethiodised oil marking was performed 1-3 days before PCA in 99 patients with 99 RCCs from 2016 to 2020. Ethiodised oil retention on CT images was evaluated retrospectively and CT attenuation values in the tumour were measured. Regions of interest (ROI) were placed on the tumours to calculate: average (ROI-average), maximal (ROI-max), minimum (ROI-min), and standard deviation (ROI-SD). Qualitative scores comprising a five-point scale (5, excellent; 1, poor) were evaluated for the retention scores (RS) of ethiodised oil in the tumour (ethiodised oil-RS) and the visualisation scores (VS) of the boundary between the tumour and renal parenchyma (boundary-VS).

RESULTS

The histological subtypes comprised clear cell (ccRCC; n=85), papillary (pRCC; n=6), and chromophobe/oncocytoma renal cell carcinoma (chrRCC; n=8). The mean ROI-average, ROI-max, and ROI-SD were significantly higher in ccRCCs than in chrRCCs and pRCCs (p<0.05). The mean ethiodised oil-RS was significantly lower in pRCCs than in ccRCCs (p=0.039), and the mean boundary-VS was >4 in all subtypes. Even with poor intratumour ethiodised oil retention (n=6), sufficient boundary-VS was obtained due to "inverted marking." All PCA procedures were completed without additional intravenous contrast material injection at the time of PCA.

CONCLUSION

Regardless of the tumour subtypes, ethiodised oil marking aids in visualising the boundary between the tumour and parenchyma on non-contrast CT in PCA.

Stacking of a Cofacially Stacked Iron Phthalocyanine Dimer on Graphite Achieved High Catalytic CH4 Oxidation Activity Comparable to That of pMMO

Numerous biomimetic molecular catalysts inspired by methane monooxygenases (MMOs) that utilize iron or copper-oxo species as key intermediates have been developed. However, the catalytic methane oxidation activities of biomimetic molecule-based catalysts are still much lower than those of MMOs. Herein, we report that the close stacking of a μ-nitrido-bridged iron phthalocyanine dimer onto a graphite surface is effective in achieving high catalytic methane oxidation activity. The activity is almost 50 times higher than that of other potent molecule-based methane oxidation catalysts and comparable to those of certain MMOs, in an aqueous solution containing H₂O₂. It was demonstrated that the graphite-supported μ-nitrido-bridged iron phthalocyanine dimer oxidized methane, even at room temperature. Electrochemical investigation and density functional theory calculations suggested that the stacking of the catalyst onto graphite induced partial charge transfer from the reactive oxo species of the μ-nitrido-bridged iron phthalocyanine dimer and significantly lowered the singly occupied molecular orbital level, thereby facilitating electron transfer from methane to the catalyst in the proton-coupled electron-transfer process. The cofacially stacked structure is advantageous for stable adhesion of the catalyst molecule on the graphite surface in the oxidative reaction condition and for preventing decreases in the oxo-basicity and generation rate of the terminal iron-oxo species. We also demonstrated that the graphite-supported catalyst exhibited appreciably enhanced activity under photoirradiation owing to the photothermal effect.

Tripodal Triazatruxene Derivative as a Face-On Oriented Hole-Collecting Monolayer for Efficient and Stable Inverted Perovskite Solar Cells

Hole-collecting monolayers have drawn attention in perovskite solar cell research due to their ease of processing, high performance, and good durability. Since molecules in the hole-collecting monolayer are typically composed of functionalized π-conjugated structures, hole extraction is expected to be more efficient when the π-cores are oriented face-on with respect to the adjacent surfaces. However, strategies for reliably controlling the molecular orientation in monolayers remain elusive. In this work, multiple phosphonic acid anchoring groups were used to control the molecular orientation of a series of triazatruxene derivatives chemisorbed on a transparent conducting oxide electrode surface. Using infrared reflection absorption spectroscopy and metastable atom electron spectroscopy, we found that multipodal derivatives align face-on to the electrode surface, while the monopodal counterpart adopts a more tilted configuration. The face-on orientation was found to facilitate hole extraction, leading to inverted perovskite solar cells with enhanced stability and high-power conversion efficiencies up to 23.0%.

Extraordinary Acceleration of an Electrophilic Reaction Driven by the Polar Surface of 2D Aluminosilicate Nanosheets

To increase chemical reaction rates, general solutions include increasing the concentration/temperature and introducing catalysts. In this study, the rate constant of an electrophilic metal coordination reaction is accelerated 23-fold on the surface of layered aluminosilicate (LAS), where the reaction substrate (ligand molecule) induces dielectric polarization owing to the polar and anionic surface. According to the Arrhenius plot, the frequency factor (A) is increased by almost three orders of magnitude on the surface. This leads to the conclusion that the collision efficiency between the ligands and metal ions is enhanced on the surface due to the dielectric polarization. This is surprising because one side of the ligand is obscured by the surface, so the collision efficiency is expected to be decreased. This unique method to accelerate the chemical reaction is expected to expand the range of utilization of LASs, which are chemically inert, abundant, and environmentally friendly. The concept is also applicable to other metal oxides which have polar surfaces, which will be useful for various chemical reactions in the future.

Coordination-Induced Trigger for Activity: N-Heterocyclic Carbene-Decorated Ceria Catalysts Incorporating Cr and Rh with Activity Induction by Surface Adsorption Site Control

A coordination-induced trigger for catalytic activity is proposed on an N-heterocyclic carbene (NHC)-decorated ceria catalyst incorporating Cr and Rh (ICy-r-Cr_0.19Rh_0.06CeO_z). ICy-r-Cr_0.19Rh_0.06CeO_z was prepared by grafting 1,3-dicyclohexylimidazol-2-ylidene (ICy) onto H₂-reduced Cr_0.19Rh_0.06CeO_z (r-Cr_0.19Rh_0.06CeO_z) surfaces, which went on to exhibit substantial catalytic activity for the 1,4-arylation of cyclohexenone with phenylboronic acid, whereas r-Cr_0.19Rh_0.06CeO_z without ICy was inactive. FT-IR, Rh K-edge XAFS, XPS, and photoluminescence spectroscopy showed that the ICy carbene-coordinated Rh nanoclusters were the key active species. The coordination-induced trigger for catalytic activity on the ICy-bearing Rh nanoclusters could not be attributed to electronic donation from ICy to the Rh nanoclusters. DFT calculations suggested that ICy controlled the adsorption sites of the phenyl group on the Rh nanocluster to promote the C-C bond formation of the phenyl group and cyclohexenone.

Low-temperature selective oxidation of methane to methanol over a platinum oxide

The low-temperature activation of methane is highly important as a reaction that can dissociate the strongest C-H bond and convert it into useful compounds. This study demonstrated that supported platinum oxide was found to activate methane near room temperature and selectively afford methanol in the presence of oxygen.

Mechanistic origins of accelerated hydrogenation of mixed alkylaromatics by synchronised adsorption over Rh/SiO2

Catalytic reactions of mixed substrates sometimes behave differently from those of individual substrates. For example, the hydrogenation of propylbenzene over Rh/SiO2 proceeds 120% faster in the presence of toluene. Such...

Exploring the Optimal Alloy for Nitrogen Activation by Combining Bayesian Optimization with Density Functional Theory Calculations

Binary alloy catalysts have the potential to exhibit higher activity than monometallic catalysts in nitrogen activation reactions. However, owing to the multiple possible combinations of metal elements constituting binary alloys, an exhaustive search for the optimal combination is difficult. In this study, we searched for the optimal binary alloy catalyst for nitrogen activation reactions using a combination of Bayesian optimization and density functional theory calculations. The optimal alloy catalyst proposed by Bayesian optimization had a surface energy of ∼0.2 eV/Ų and resulted in a low reaction heat for the dissociation of the N≡N bond. We demonstrated that the search for such binary alloy catalysts using Bayesian optimization is more efficient than random search.

Oxidative Addition of Methane and Reductive Elimination of Ethane and Hydrogen on Surfaces: From Pure Metals to Single Atom Alloys

Oxidative addition of CH₄ to the catalyst surface produces CH₃ and H. If the CH₃ species generated on the surface couple with each other, reductive elimination of C₂H₆ may be achieved. Similarly, H's could couple to form H₂. This is the outline of nonoxidative coupling of methane (NOCM). It is difficult to achieve this reaction on a typical Pt catalyst surface. This is because methane is overoxidized and coking occurs. In this study, the authors approach this problem from a molecular aspect, relying on organometallic or complex chemistry concepts. Diagrams obtained by extending the concepts of the Walsh diagram to surface reactions are used extensively. C-H bond activation, i.e., oxidative addition, and C-C and H-H bond formation, i.e., reductive elimination, on metal catalyst surfaces are thoroughly discussed from the point of view of orbital theory. The density functional theory method for structural optimization and accurate energy calculations and the extended Hückel method for detailed analysis of crystal orbital changes and interactions play complementary roles. Limitations of monometallic catalysts are noted. Therefore, a rational design of single atom alloy (SAA) catalysts is attempted. As a result, the effectiveness of the Pt₁/Au(111) SAA catalyst for NOCM is theoretically proposed. On such an SAA surface, one would expect to find a single Pt monatomic site in a sea of inert Au atoms. This is desirable for both inhibiting overoxidation and promoting reductive elimination.

POS1441 INFLUENCE OF ENVIRONMENTAL AND GENETIC FACTORS ON SERUM IGG4 DURING HEALTH CHECKUPS IN NAGASAKI ISLAND STUDY

Background

Although serum IgG4 levels are important for the diagnosis of IgG4-related diseases (IgG4-RD), few studies have validated IgG4 levels in healthy individuals in large resident medical examination cohorts and investigated background factors associated with serum IgG4.

A report on genetic factors shows that HLA loci associate with IgG4-RD found in Japanese nation-wide IgG4-RD registry1). However, environmental and genetic factors related to the elevated serum IgG4 levels, which may closely associate with development of IgG4-RD, have previously been unclear in healthy subjects. The nephelometric immunoassay (NIA) is conventionally used to measure IgG4, but it requires a relatively large amount of serum. The magnetic bead panel assay (MBA), which can evaluate IgG4 levels with only a few ml of serum, has an advantage compared with NIA regarding to required sample volume, but the correlation between the two methods is unclear.

Objectives

First, we attempted to verify the accuracy of the MBA compared to the standard NIA in the first cohort. Next, we examined the relationship between IgG4 measured by the MBA and background information of healthy subjects to identify variables that correlate with serum IgG4 in the second cohort.

Methods

First, Kanazawa University collected 947 samples from the resident health examination, and IgG4 levels were measured by both MBA and NIA, and the correlation between the two was verified using Spearman’s rank correlation coefficient (first cohort). Next (second cohort), serum IgG4 of 3240 samples of Nagasaki Island Study (NaIS), which had started in 2014 collaborating among Nagasaki University and Goto City, Nagasaki Prefecture, intended for research of varying conditions and diseases including IgG4-RD, were then measured by MBA. These subjects were stratified into the two groups as IgG4-high and IgG4-within normal limit using the aforementioned cutoff values, and compared with background information such as age, gender, drinking, smoking, uric acid, serum creatinine, comorbidities and HLA typing, including DRB1*04:06, *04:03, *04:05, *04:10 as disease-susceptibility gene, DRB1*09:01 and DQB1*03:03 as protective gene1).

Results

IgG4 by MBA correlated well with IgG4 by NIA (r=0.94, p-value<0.001) which was determined from Kanazawa samples (N=947). 1,463.6 mg/mL of IgG4 of MBA corresponded to 135 mg/dl, the normal cut-off value for IgG4 by NIA. In the analysis of NaIS samples (N=3240), the overall high IgG4 positivity rate was 6.3%. Multivariable analysis including age, gender, smoking and drinking, led by univariate analysis, showed that gender and smoking were significantly associated with high serum IgG4 positivity (male: odds ratio = 1.8, 95%CI =1.2-2.7, p = 0.009, smoking: odds ratio = 1.7, 95%CI =1.1-2.5, p = 0.012). There was no association between high serum IgG4 level and HLA genotyping.

Conclusion

We concluded that MBA is a good method to measure serum IgG4 even by the very small sample volume. In our study, the prevalence of serum IgG4 positivity was high tendency than previous report2). Our data showed that male and smoking are independent factors associated with high serum IgG4 positivity. There were no association between serum IgG4 level and HLA genotyping in healthy subjects. Further comprehensive investigation is necessary to clarify high risk subjects who will develop IgG4-RD.

References

[1]Terao C, et al. Lancet Rheumatol 2019;1: e14–22.

[2]Carballo I, et al. PLoS One. 2016;11: e0149330.

Disclosure of Interests

None declared

Theoretical Study on the Contribution of Interfacial Functional Groups to the Adhesive Interaction between Epoxy Resins and Aluminum Surfaces

To ensure the quality and reliability of products bonded by epoxy resin adhesives, elucidation of the microscopic adhesion mechanism is essential. The adhesive interaction and bonding strength between epoxy resins and hydroxylated γ-alumina (001) surfaces were investigated by using a combined molecular dynamics (MD) and density functional theory (DFT) study. The curing reaction of an epoxy resin consisting of diglycidyl ether of bisphenol A (DGEBA) and 4,4'-diaminodiphenyl sulfone (DDS) was simulated. The resin structure was divided into fragmentary structures to study the interaction of each functional group with the alumina surface using DFT calculations. From the characteristics of the adhesive structures and the calculated adhesion energies, it was found that the fragments forming hydrogen bonds with hydroxy groups on the alumina surface resulted in large adhesion energies. On the other hand, the fragments adsorbed on the alumina surface via dispersion interactions resulted in small adhesion energies. The adhesion forces evaluated from the Hellmann-Feynman force calculations indicated the significant contribution of the hydroxy groups and benzene ether moieties derived from DGEBA to the adhesive stress of the DGEBA/DDS epoxy resin. The direction of hydrogen bonding between the epoxy resin and the surface and the difference in geometry at the interface between the donor and acceptor of hydrogen bonding played a central role in maintaining the adhesive strength during the failure process of the adhesive interface.

Peel Adhesion Strength between Epoxy Resin and Hydrated Silica Surfaces: A Density Functional Theory Study

Adhesive strength is known to change significantly depending on the direction of the force applied. In this study, the peel and tensile adhesive forces between the hydroxylated silica (001) surface and epoxy resin are estimated based on quantum chemical calculations. Here, density functional theory (DFT) with dispersion correction is used. In the peel process, the epoxy resin is pulled off from the terminal part, while in the tensile process, the entire epoxy resin is pulled off vertically. As a result of these calculations, the maximum adhesive force in the peel process is decreased to be about 40% of that in the tensile process. The adhesion force-displacement curve for the peeling process shows two characteristic peaks corresponding to the process where the adhesive molecule horizontally oriented to the surface shifts to a vertical orientation to the surface and the process where the vertical adhesive molecule is dissociated from the surface. Force decomposition analysis is performed to further understand the peel adhesion force; the contribution of the dispersion force is found to be slightly larger than that of the DFT force. This feature is common to the tensile process as well. Each force in the peel process is about 40% smaller than the corresponding force in the tensile process.

Homogeneous catalyst modifier for alkyne semi-hydrogenation: systematic screening in an automated flow reactor and computational study on mechanisms

21 types of modifiers are screened for palladium catalysed semi-hydrogenation of alkynes with varying catalyst type, reaction time, and target substrate using an automated flow reactor system.

Shear adhesive strength between epoxy resin and copper surfaces: a density functional theory study

Shear adhesive strengths of epoxy resin for copper and copper oxide surfaces are estimated based on quantum chemical calculations. Shear adhesion has periodicity, and its origin is revealed.

Molecular Dynamics Study on the Thermal Aspects of the Effect of Water Molecules at the Adhesive Interface on an Adhesive Structure

The presence of adsorbed water on hydrophilic solid surfaces should be taken into account, especially in humid environments. It significantly reduces the adhesive strength between the epoxy resin and the adherend surface. Here, the adhesion structure of interfacial water sandwiched between bisphenol A epoxy resin and a hydroxylated silica (001) surface is investigated with microsecond molecular dynamics simulations. Specifically, interfacial water layers with initial thicknesses of 7.5, 10, and 20 Å are modeled. The density curves of water and the diglycidyl ether of bisphenol A show that at room temperature, the surface of the silica with hydroxyl groups is completely covered with a thick layer of water. For water layers thinner than 10 Å, the density of epoxy resin on the silica surface increases when the system is heated and does not return to the original density when the system is cooled. Furthermore, calculation of the interaction energy revealed that the exclusion of water from the hydroxylated surface by epoxy resin during heating can contribute to the increase in the adhesive interaction between the epoxy resin and the silica surface with hydroxyl groups.

Elucidation of Adhesive Interaction between the Epoxy Molding Compound and Cu Lead Frames

Clarification of adhesive interactions in semiconductor packages can improve reliability of power electronics. In this study, the adhesion interfaces between the epoxy molding compound and Cu-based lead frames were analyzed using the density functional theory. A resin fragment was prepared based on the polymer framework formed in the curing reaction of epoxy cresol novolac (ECN) and phenol novolac (PN), which are typical molding materials. The resin fragment was optimized on the surfaces of Cu and Cu2O. We calculated the charge density differences for adhesion structures and discussed the origin of adhesive interactions. The ECN-PN fragment's adhesion to the Cu surface relied mainly on dispersion forces, whereas in the case of Cu2O, the resin bonded chemically to the surface via (1) σ-bonds formed between the ECN-PN's OH group oxygen and coordinatively unsaturated copper (CuCUS) and (2) hydrogen bonds between resin's OH groups and coordinatively unsaturated oxygen (OCUS) located close to to CuCUS, resulting in a stable adhesive structure. The energy required to detach the resin fragment from the optimized structure was determined using the nudged elastic band method in each model of the adhesive interface. Morse potential curve was used to approximate the obtained energy, and the energy differentiation by detachment distance yielded the theoretical adhesive force. The maximum adhesive stress was 1.6 and 2.2 GPa for the Cu and Cu2O surfaces, respectively. The extent to which the ECN-PN fragment bonded to the Cu2O surface stabilized was 0.5 eV higher than in the case of the Cu surface.

Cavin-1 modulates BMP/Smad signaling through the interaction of Caveolin-1 with BMPRII in pulmonary artery endothelial cells

Background

Pulmonary hypertension (PH) is a progressive disease associated with poor outcomes. Caveolin-1 (Cav1) and Cavin-1 are components of caveolae, and Cav1 is identified as a related gene of pulmonary arterial hypertension (PAH). Gene mutations of bone morphogenetic protein type II receptor (BMPRII) is the most common cause of PAH. BMPRII is localized in caveolae and associates with Cav1. However, the role of the Caveolin-Cavin system on the BMP/Smad signaling and the PAH progression has not been well-known.

Purpose

Our study aims to investigate the relationship between Caveolin-Cavin system and BMP/Smad signaling pathway in pulmonary artery endothelial cells (PAECs). [Methods] Cav1 knockout mice were used to assess PH, and caveolae in PAECs were observed by electron microscope. After knocking down Cav1 and/or Cavin-1 in human PAECs (hPAECs) using siRNA, we evaluated the phosphorylation of Smad by Western blotting. Apoptosis was explored by flow cytometry. To assess the interaction between Cav1 and BMPRII, and the effect of Cavin-1 for this interaction and BMP/Smad signaling, we performed immunoprecipitation, Co-immunostaining, Proximal Ligation Assay (PLA), GST pulldown assay, and Western blotting.

Results

As in previous reports, Cav1 knockout mice exhibited PH with pulmonary vascular remodeling and right ventricular hypertrophy and PAECs isolated from Cav1 knockout mice showed caveolae disappearance. Cav1 knockdown in hPAECs reduced BMPRII at the plasma membrane and Smad 1/5/9 phosphorylation. Cav1 knockdown also significantly increased hypoxia-induced apoptosis in hPAECs. Co-immunostaining revealed that Cav1 was associated with BMPRII at the membrane of hPAECs. Cavin-1 inhibited the interaction of BMPRII with Cav1 and reduced BMPRII localization on the membrane of hPAECs. GST pulldown assay revealed that Cavin-1 and BMPRII were associated with Cav1 through the scaffolding domain in Cav1. These findings suggest that Cavin-1 and BMPRII are competitively associated with Cav1. Cavin-1 knockdown improved the interaction between Cav1 and BMPRII and inhibited both BMPRII reduction at the plasma membrane and Smad 1/5/9 dephosphorylation.

Conclusions

Cavin-1 affects the interaction of Cav1 with BMPRII at the plasma membrane and modulates BMP/Smad signaling in PAECs. The binding of Cavin-1 to Cav1 enhances the interaction between BMPR2 and Cav1, resulting in stabilization of BMPRII localization at the plasma membrane in PAECs and prevention of BMP/Smad signaling attenuation, which is important for PAH development.

Funding Acknowledgement

Type of funding sources: None.

Competition between Hydrogen Bonding and Dispersion Force in Water Adsorption and Epoxy Adhesion to Boron Nitride: From the Flat to the Curved

Hexagonal boron nitride (h-BN) is a material with excellent thermal conductivity and electrical insulation, used as an additive to various matrices. To increase the affinity of h-BN to them, hydrogen bonds should be formed at the interface. In reality, however, they are not formed; the N atoms are not capable of accepting hydrogen bonds due to the delocalization of their lone pair electrons over the B-N π bonds. To make it form hydrogen bonds, one may need to break the planarity of h-BN so that the orbital overlap in the B-N π bonds can be reduced. This idea is verified with first-principles calculations on the adsorption of a water molecule on hypothetical h-BN surfaces, the planarity of which is broken. One can do it in silico but not in vitro. BN nanotubes (BNNTs) are considered as a more realistic BN surface with nonplanarity. The hydrogen bond is shown to become stronger as the curvature of the tube increases. On the contrary, the strength of the dispersion force acting at the interface becomes weaker. In water adsorption, these two interactions are in competition with each other. However, in epoxy adhesion, the interaction due to dispersion forces is overwhelmingly stronger than that due to hydrogen bonding. The smaller the curvature of the surface, the smaller the distance between more atoms at the interface; thus, the interaction due to dispersion forces maximized.

Ultrasound efficacy of targeted-synthetic disease-modifying anti-rheumatic drug treatment in rheumatoid arthritis: a multicenter prospective cohort study in Japan

OBJECTIVE

This study investigated the effectiveness of treatment with Janus kinase (JAK) inhibitors in rheumatoid arthritis (RA) assessed by ultrasonography (US) activity, and the influence of patient characteristics and previous treatments.

METHOD

This prospective study assessed 60 treatment initiations among 53 Japanese patients diagnosed with RA who underwent treatment with JAK inhibitors during June 2013 to February 2020. Of the 53 patients, seven patients were enrolled in duplicate because they were treated with two different JAK inhibitors at different periods. For each case, the improvement rate on the power Doppler (PD) score was assessed at 6 month follow-up. Median improvement rate of PD score was used to classify cases as either US responders or non-responders, and patient characteristics were compared between the two groups.

RESULTS

All indicators of clinical disease activity and US activity showed a significant improvement at 3 months compared with baseline. Although the JAK inhibitor-cycler group and the interleukin-6 (IL-6) inhibitor inadequate response (IR) group tended to show a later improvement for US activity, all indicators of clinical disease activity and US activity showed a significant improvement at 6 months compared with baseline for both groups. Multivariate analysis showed that concomitant methotrexate use and an IR to the previous biologic or targeted-synthetic disease-modifying anti-rheumatic drug (b/tsDMARD) treatment were independently and significantly associated with US responders.

CONCLUSION

Use of a JAK inhibitor in combination with methotrexate and an absence of IR to any previous b/tsDMARDs demonstrated superior effectiveness for patients with RA.

Bonding of C1 fragments on metal nanoclusters: a search for methane conversion catalysts with swarm intelligence

There is a need for a catalyst that can directly convert methane into useful substances. The use of Ni as a catalyst for the steam reforming of methane has led us to look at Ni nanoclusters as potential candidates for the direct conversion of methane. Fe, Co, Cu, and Zn nanoclusters are also focused on. How the type of C1 fragments (CH4, CH3, CH2, CH, and C) stabilized by the metal nanoclusters as adsorbed species varies with metal species is theoretically investigated. The particle swarm optimization algorithm, which is based on swarm intelligence, as well as density functional theory, is used for this calculation. The Ni nanoclusters are found to preferentially adsorb C as a stable species, the Fe and the Co nanoclusters both CH and CH3, and the Cu nanoclusters CH3; the Zn nanoclusters are found not to chemisorb any C1 fragment. The methane activation capacity can be ranked in the order of Ni > Fe > Co > Cu > Zn. The highest methane activation capacity of Ni is due to the strongest covalent nature of the interaction between Ni and the adsorbed species. The ionicity of the bond between Fe and the adsorbed species is higher than that between Co and the adsorbed species, while the covalent nature of the bonds is comparable for both. The weak methane activation ability of Cu compared to Fe, Co, and Ni is found to be due to the fact that both the covalent and ionic bond strengths between Cu and the adsorbed species are weak. Zn and the adsorbed species form neither ionic nor covalent bonds. These results indicate that the Fe and the Co nanoclusters as well as the Ni may lead to the over-oxidation of methane, whereas the Zn nanoclusters cannot activate methane in the first place; therefore, their application to direct methane conversion catalysts is unlikely. Since the Cu nanoclusters do not adsorb C and CH as stable species, but CH3 stably, the Cu nanoclusters are expected to work as a catalyst for the direct conversion of methane.

POS1429 ORAL DYSBIOSIS REFLECTS THE IMMUNOLOGICAL ALTERATION OF RA REGARDING TO HLA DRB1*SE, ACPA AND CIGARETTE SMOKING: NAGASAKI ISLAND STUDY

Background:

Anti-citrullinated protein antibody (ACPA) production is observed in several organs even prior to the onset of rheumatoid arthritis (RA), and oral mucosa is considered to be one of the important tissues. Saliva is considered to reflect the oral microbiota(oralMB) including periodontal disease. A gene-environment interaction between cigarette smoking and shared epitope genes in HLA-DRB1*shared epitope (SE) provides a high risk of ACPA-positive RA. However, the interaction of HLA-DRB1*SE, ACPA, cigarette smoking and oralMB of RA patients remains to be elucidated.

Objectives:

We investigated that the difference of oralMB among RA patients and healthy subjects(HS) regarding to ACPA, HLA-DRB1*SE and cigarette smoking.

Methods:

The Nagasaki Island Study, which had started in 2014 collaborating with Goto City, Nagasaki Prefecture, Japan, is intended for research of the preclinical stage of RA, including ACPA, HLA genotype screening, oralMB and lifestyle habit. Both of blood and salivary samples were obtained from 1422 subjects out of 4276 participants in this study from 2016 to 2018. ACPA positivity was 1.7 % in total 4276 subjects. At this point, we selected 291 subjects, who were ACPA positive non-RA HS(n=22) and patients with RA (n=33, 11 subjects were ACPA positive and 22 ACPA negative, respectively) as the case, age and gender matched ACPA negative non-RA HS (n=236) as the control. In RA subjects, current smoker was n=1(3.0%) and ever smoker was n=8(24.2%). In HS, current smoker was n=29(11.2%) and ever smoker was n=55(21.3%). ACPA was measured by ELISA, and HLA genotyping was quantified by next-generation sequencing (Ref.1). The operational taxonomic unit (OTU) analysis using 16S rRNA gene sequencing were performed. The richness of microbial diversity within subject (α-diversity) was scaled via Shannon entropy. The dissimilarity between microbial community composition was calculated using Bray-Curtis distance as a scale, and differences between groups (β-diversity) were tested by permutational multivariate analysis of variance (PERMANOVA). In addition, UniFrac distance calculated in consideration of the distance on the phylogenetic tree were performed.

Results:

Median age 71 y.o., % Female 58.4 %. Among RA and non-RA subjects, not α-diversity but β-diversity was statistically smaller significantly in RA (p=0.022). In the HS, there was no decrease in α-diversity between the ACPA-positive and HLA-DRB1*SE-positive groups, but in the ACPA-positive group, there was a decrease in α-diversity in the HLA-DRB1*SE-positive group. When we compared α-diversity stratified by the presence or absence of three factors (RA, ACPA, and HLA-DRB1*SE), the RA group with ACPA and HLA-DRB1*SE positive tended to have the lowest diversity (Figure 1 lower right). RA subjects, presence of HLA-DRB1*SE did not show the difference but the tendency of lower α-diversity (p=0.29).

Conclusion:

HS with ACPA-positive HLA-DRB1*SE tended to show lower α-diversity than ACPA-positive HS and HLA-DRB1*SE positive HS. Furthermore, RA subjects with ACPA-positive HLA-DRB1*SE showed lower α-diversity than HS with ACPA-positive HLA-DRB1*SE.

Our study suggested that the oral dysbiosis may reflect the immunological status of patients with RA. Because of the small number of ACPA-positive patients, stratification by smoking history was difficult. Further examination is needed to clarify the gene-environment interaction and microbiome.

References:

[1]Kawaguchi S, et al. Methods Mol Biol 2018;1802: 22.

Disclosure of Interests:

None declared

Mixed Anion Control of the Partial Oxidation of Methane to Methanol on the β-PtO2 Surface

Although the C-H bond of methane is very strong, it can be easily dissociated on the (110) surface of β-PtO2. This is because a very stable Pt-C bond is formed between the coordinatively unsaturated Pt atom and CH3 on the surface. Owing to the stable nature of the Pt-C bond, CH3 is strongly bound to the surface. When it comes to methanol synthesis from methane, the Pt-C bond has to be cleaved to form a C-O bond during the reaction process. However, this is unlikely to occur on the β-PtO2 surface: The activation energy of the process is calculated to be so large as 47.9 kcal/mol. If the surface can be modified in such a way that the ability for the C-H bond activation is maintained but the Pt-C bond is weakened, a catalyst combining the functions of C-H bond cleavage and C-O bond formation can be created. For this purpose, analyzing the orbital interactions on the surface is found to be very useful, resulting in a prediction that the Pt-C bond can be weakened by replacing the O atom trans to the C atom with a N atom. This would be a sort of process to make β-PtO2 a mixed anion compound. Density functional theory simulations of catalytic reactions on the β-PtO2 surface show that the activation energy of the rate-limiting step of methanol synthesis can be reduced to 27.7 kcal/mol by doping the surface with N.

Theoretical Study on the Adhesion Interaction between Epoxy Resin Including Curing Agent and Plated Gold Surface

In this study, the adhesive interaction between gold and epoxy resin is theoretically investigated. These materials make up crucial components of a wide range of electronic devices. The objectives of the study are (1) to elucidate the bonding mechanism between epoxy resin and a realistic gold surface, and (2) to obtain a device-design guideline for superior adhesion, thus reducing the bonding breakage that may potentially cause device failure. Die pad surfaces used in chip attachment methods for microelectronics are usually fabricated using an electrolytic plating technique. This technique involves ionic gold solutions like K[Au(CN)₂]. The combined theoretical and experimental studies previously carried out by the authors have revealed that the CN^- counteranion of the gold cation has a high affinity for gold and is likely to remain on the realistic gold surface generated by plating. However, the cyano group content on the surface of the plated gold is still unknown. Therefore, gold surfaces embedded with cyano groups with various coverages are constructed. The effect of the varying coverage of the cyano groups on the adhesion strength is inspected using first-principles density functional theory calculations. As the number of cyano groups on the surface increases, the direct interaction between the gold surface and the epoxy resin is hindered, but the hydroxy and amino groups in the epoxy resin and hardener form more hydrogen bonds with the cyano groups adsorbed on the surface. It is found that the surface with intermediate cyano coverage (about 33%) yields the highest adhesive strength.

Characterization of a TNFR2-Selective Agonistic TNF-α Mutant and Its Derivatives as an Optimal Regulatory T Cell Expander

Regulatory T cells (Tregs) are a subpopulation of lymphocytes that play a role in suppressing and regulating immune responses. Recently, it was suggested that controlling the functions and activities of Tregs might be applicable to the treatment of human diseases such as autoimmune diseases, organ transplant rejection, and graft-versus-host disease. TNF receptor type 2 (TNFR2) is a target molecule that modulates Treg functions. In this study, we investigated the role of TNFR2 signaling in the differentiation and activation of mouse Tregs. We previously reported the generation of a TNFR2-selective agonist TNF mutant, termed R2agoTNF, by using our unique cytokine modification method based on phage display. R2agoTNF activates cell signaling via mouse TNFR2. In this study, we evaluated the efficacy of R2agoTNF for the proliferation and activation of Tregs in mice. R2agoTNF expanded and activated mouse CD4⁺CD25⁺ Tregs ex vivo. The structural optimization of R2agoTNF by internal cross-linking or IgG-Fc fusion selectively and effectively enhanced Treg expansion in vivo. Furthermore, the IgG-Fc fusion protein suppressed skin-contact hypersensitivity reactions in mice. TNFR2 agonists are expected to be new Treg expanders.

Effect of infant pelage colour on infant caring by other group members: a case study of wild Javan lutungs (Trachypithecus auratus)

We observed interactions of group members with seven Javan lutungs (Trachypithecus auratus) infants from January to March 2018. Infants’ pelage colouration changed from bright yellow to black, and it took about 2.9 months (on average) until the yellowness disappeared, and about 6.1 months (on average) until the colouration change was completed. Infants with yellow pelage spent more time being held and screaming, while infants with black pelage spent more time moving and feeding. The number of neighbouring animals decreased as the infants’ pelage became black, which implied that group members are attracted to the yellowness of infants. As the pelage became black and the infant aged, the neighbouring animals exhibited more social behaviour. Our results implied that bright yellow pelage colour triggers their parental instincts. The bright pelage colour would benefit infants because group members protect them from unfamiliar males and predators.

From Infection Clusters to Metal Clusters: Significance of the Lowest Occupied Molecular Orbital (LOMO)

In this paper, the nature of the lowest-energy electrons is detailed. The orbital occupied by such electrons can be termed the lowest occupied molecular orbital (LOMO). There is a good correspondence between the Hückel method in chemistry and graph theory in mathematics; the molecular orbital, which chemists view as the distribution of an electron with a specific energy, is to mathematicians an algebraic entity, an eigenvector. The mathematical counterpart of LOMO is known as eigenvector centrality, a centrality measure characterizing nodes in networks. It may be instrumental in solving some problems in chemistry, and also it has implications for the challenge facing humanity today. This paper starts with a demonstration of the transmission of infectious disease in social networks, although it is unusual for a chemistry paper but may be a suitable example for understanding what the centrality (LOMO) is all about. The converged distribution of infected patients on the network coincides with the distribution of the LOMO of a molecule that shares the same network structure or topology. This is because the mathematical structures behind graph theory and quantum mechanics are common. Furthermore, the LOMO coefficient can be regarded as a manifestation of the centrality of atoms in an atomic assembly, indicating which atom plays the most important role in the assembly or which one has the greatest influence on the network of these atoms. Therefore, it is proposed that one can predict the binding energy of a metal atom to its cluster based on its LOMO coefficient. A possible improvement of the descriptor using a more sophisticated centrality measure is also discussed.

Neutropenia and survival outcomes in metastatic colorectal cancer patients treated with trifluridine/tipiracil in the RECOURSE and J003 trials

Background:

The phase II J003 (N = 169) and phase III RECOURSE (N = 800) trials demonstrated a significant improvement in survival with trifluridine (FTD)/tipiracil (TPI) versus placebo in patients with refractory metastatic colorectal cancer. This post hoc analysis investigated pharmacokinetic data of FTD/TPI exposure and pharmacodynamic markers, such as chemotherapy-induced neutropenia (CIN) and clinical outcomes.

Patients and methods:

A total of 210 patients from RECOURSE were enrolled in this substudy. A limited sampling approach was used, with three pharmacokinetic samples drawn on day 12 of cycle 1. Patients were categorized as being above or below the median area under the plasma concentration–time curve (AUC) for FTD and TPI. We conducted a post hoc analysis using the entire RECOURSE population to determine the correlations between CIN and clinical outcome. We then carried out a similar analysis on the J003 trial to validate the results.

Results:

In the RECOURSE subset, patients in the high FTD AUC group had a significantly increased CIN risk. Analyses of the entire population demonstrated that FTD/TPI-treated patients with CIN of any grade in cycles 1 and 2 had significantly longer median overall survival (OS) and progression-free survival (PFS) than patients who did not develop CIN and patients in the placebo group. Patients who required an FTD/TPI treatment delay had increased OS and PFS versus those in the placebo group and those who did not develop CIN. Similar results were obtained in the J003 cohort.

Conclusions:

In RECOURSE, patients with higher FTD drug exposure had an increased CIN risk. FTD/TPI-treated patients who developed CIN had improved OS and PFS versus those in the placebo group and those who did not develop CIN. Similar findings were reported in the J003 cohort, thus validating the RECOURSE results. The occurrence of CIN may be a useful predictor of treatment outcomes for FTD/TPI-treated patients.

ClinicalTrials.gov identifier:

NCT01607957 (RECOURSE).

Japan Pharmaceutical Information Center number:

JapicCTI-090880 (J003).

Cavin-1 regulates BMP/Smad signaling through the interaction of Caveolin-1 with BMPRII in pulmonary artery endothelial cells

Background

Pulmonary hypertension (PH) is a progressive disease associated with poor outcome. Caveolin-1 (Cav1) is a component of caveolae and classified as a related gene of pulmonary arterial hypertension (PAH). Gene mutations of bone morphogenetic protein type II receptor (BMPRII) is a most common cause of PAH. BMPRII is localized in caveolae and associates with Cav1. However, the role of the Caveolin-Cavin system on the BMP/Smad signaling and the PAH progression has not been well-known.

Purpose

The aim of our study is to investigate the relationship between Caveolin-Cavin system and BMP/Smad signaling pathway and explore the mechanism of downstream signal transduction of BMP signaling by the interaction between Caveolin and BMPRII.

Methods

Cav1 knockout mice were used to assess PH and caveolae in pulmonary artery endothelial cells were observed by electron microscope. Cav1 and Cavin-1, which is a component of caveolae and form a complex with Cav1, were knocked-down in human pulmonary artery endothelial cell (hPAEC) using siRNA and phosphorylation of Smad signal was evaluated. Apoptosis of these cells was explored by flow cytometry. We investigated the interaction between Cav1 and BMPRII, and evaluated whether Cavin-1 affects this interaction and signal transduction of BMP signaling.

Results

As previously described, deletion of Cav1 revealed disappearance of caveolae in pulmonary artery endothelial cells (PAECs), and Cav1 knockout mice exhibited PH with pulmonary vascular remodeling and right ventricular hypertrophy. We then examined roles of Cav1 in human PAECs (hPAECs). Cav1 knockdown in hPAECs reduced phosphorylation of Smad 1/5/9. In addition, Cav1 knockdown significantly increased hypoxia-induced apoptosis in hPAEC. Knockdown of Cavin-1 reversed phosphorylation of Smad 1/5/9 decreased by Cav1 knockdown in BMP9 stimulation. Cavin-1 reversed the expression of BMPRII decreased by overexpression of Cav1. Cav1 was associated with Cavin-1 at the plasma membrane in PAECs. Cav1 also associated with BMPRII at the membrane of hPAECs that was inhibited by Cavin-1, and Cavin-1 reduced the localization of BMPRII to the membrane of hPAECs. These results suggest that BMPRII interacts with Cav1 via Cavin-1-associated localization at the plasma membrane in hPAECs, resulting in regulating BMP/Smad signaling pathway and involving in the development of PAH.

Conclusions

Cavin-1 affects the interaction of Cav1 with BMPRII at the membrane of PAECs, and regulates BMP/Smad signaling. These results reveal a previously undescribed function of Cavin-Caveolin system in the development of PAH through regulation of BMP/Smad signaling.

Funding Acknowledgement

Type of funding source: None

SDPR/Cavin-2 loss inhibits monocyte adhesion to endothelial cells in abdominal aortic aneurysm via suppressing the expression of adhesion molecules

Background

Abdominal aortic aneurysm (AAA) is a common and life-threatening vascular disease. The initial phase of AAA progression is vascular inflammation. Inflammation sites present adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1). These molecules play a crucial role in recruiting inflammatory cells to endothelial cells through NF-κB signaling. Endothelial cells express serum deprivation response (SDPR)/Cavin-2 localized in caveolae on the cell membrane. Although Cavin-2 is involved in such as cell proliferation, migration, and signal transduction, the role of Cavin-2 in vascular inflammation in the development of AAA is still unclear.

Purpose

To assess the influence of Cavin-2 deficiency in AAA development and clarify the role of Cavin-2 in the regulation of inflammatory cell adhesion in endothelial cells.

Methods

CaCl2-induced AAAs were induced by the periaortic application of 0.5 M CaCl2 in male SDPR-knockout (KO) and wild-type (WT) mice at 8–10 weeks of age. Angiotensin II (Ang II)-induced AAAs were created by 4-week-subcutaneous drug infusion in male ApoE-KO and ApoE/Cavin-2-double KO (DKO) mice at 24 weeks of age. Inflammatory response and cell adhesion were evaluated using human aortic endothelial cells (HAECs) and human monocytes (THP-1 cells).

Results

Six weeks after CaCl2 treatment, Cavin-2 deficiency significantly attenuated the development of AAAs. Elastin degradation was markedly suppressed and F4/80-positive macrophages infiltration in aortic walls were decreased in Cavin-2-KO mice. Although Ang II infusion for 4 weeks formed AAAs in ApoE KO mice and ApoE/Cavin-2-DKO mice, ApoE/Cavin-2-DKO mice exhibited the suppression of AAA formation independently of blood pressure. Immunohistochemical staining showed VCAM-1 expression on endothelial cells was suppressed in ApoE/Cavin-2-DKO mice. Further, in vitro co-culture experiment, the number of THP-1 cells adhered to TNF-treated SDPR-knockdown HAECs was decreased compared with that to control HAECs. Moreover, mRNA expression of VCAM-1 and ICAM-1 was decreased in TNFα-treated SDPR-knockdown HAECSs. Protein expression of VCAM-1 was also suppressed in TNFα-treated SDPR-knockdown HAECSs. The activity of NF-κB p65, an upstream regulator of VCAM-1 and ICAM-1,tended to be suppressed in TNFα-treated SDPR-knockdown HAECs.

Conclusion

In this study, we revealed that SDPR/Cavin-2 loss attenuated AAA development with the suppression of elastin degradation and macrophage infiltration. Our findings suggest that SDPR/Cavin-2 in the endothelial cells regulates the expression of adhesion molecules via NF-κB signaling and promotes the adhesion and infiltration of inflammatory cells to the aortic wall.

Funding Acknowledgement

Type of funding source: None

Role of Hydrogen-Bonding and OH-π Interactions in the Adhesion of Epoxy Resin on Hydrophilic Surfaces

Epoxy resin adhesives are widely used for joining metal alloys in various industrial fields. To elucidate the adhesion mechanism microscopically, we investigated the interfacial interactions of epoxy resin with hydroxylated silica (0 0 1) and γ-alumina (0 0 1) surfaces using periodic density functional theory calculations as well as density of states (DOS) and crystal orbital Hamilton population (COHP) analyses. To better understand the interfacial interactions, we employed and analyzed water and benzene molecules as hydrophilic and hydrophobic adsorbates, respectively. Structural features and calculated adhesion energies reveal that these small adsorbates have a higher affinity for the γ-alumina surface than that for the silica surface, while a fragmentary model for the epoxy resin exhibits a strong interaction with the silica surface. This discrepancy suggests that the structural features of the hydroxylated silica surface dictate its affinity to a specific species. Partial DOS and COHP curves provide evidence for the presence of OH-π interactions between the OH groups on the surfaces and the benzene rings of the epoxy resin fragments. The orbital interaction energies of the H-bonding and OH-π interactions evaluated from the integrated COHP indicate that the OH-π interaction is a nonnegligible origin of the adhesion interaction, even when polymers with hydrophobic benzene rings are adsorbed on hydroxylated surfaces.