High-throughput evaluation of hemolytic activity through precise measurement of colony and hemolytic zone sizes of engineered Bacillus subtilis on blood agar.

Biosurfactants have remarkable characteristics, such as environmental friendliness, high safety, and excellent biodegradability. Surfactin is one of the best-known biosurfactants produced by Bacillus subtilis. Because the biosynthetic pathways of biosurfactants, such as surfactin, are complex, mutagenesis is a useful alternative to typical metabolic engineering approaches for developing high-yield strains. Therefore, there is a need for high-throughput and accurate screening methods for high-yield strains derived from mutant libraries. The blood agar lysis method, which takes advantage of the hemolytic activity of biosurfactants, is one way of determining their concentration. This method includes inoculating microbial cells onto blood-containing agar plates, and biosurfactant production is assessed based on the size of the hemolytic zone formed around each colony. Challenges with the blood agar lysis method include low experimental reproducibility and a lack of established protocols for high-throughput screening. Therefore, in this study, we investigated the effects of the inoculation procedure and media composition on the formation of hemolytic zones. We also developed a workflow to evaluate the number of colonies using robotics. The results revealed that by arranging colonies at appropriate intervals and measuring the areas of colonies and hemolytic rings using image analysis software, it was possible to accurately compare the hemolytic activity among several colonies. Although the use of the blood agar lysis method for screening is limited to surfactants exhibiting hemolytic activity, it is believed that by considering the insights gained from this study, it can contribute to the accurate screening of strains with high productivity.

Engineering Escherichia coli for efficient glutathione production.

Glutathione is a tripeptide of excellent value in the pharmaceutical, food, and cosmetic industries that is currently produced during yeast fermentation. In this case, glutathione accumulates intracellularly, which hinders high production. Here, we engineered Escherichia coli for the efficient production of glutathione. A total of 4.3 g/L glutathione was produced by overexpressing gshA and gshB, which encode cysteine glutamate ligase and glutathione synthetase, respectively, and most of the glutathione was excreted into the culture medium. Further improvements were achieved by inhibiting degradation (Δggt and ΔpepT); deleting gor (Δgor), which encodes glutathione oxide reductase; attenuating glutathione uptake (ΔyliABCD); and enhancing cysteine production (PompF-cysE). The engineered strain KG06 produced 19.6 g/L glutathione after 48 h of fed-batch fermentation with continuous addition of ammonium sulfate as the sulfur source. We also found that continuous feeding of glycine had a crucial role for effective glutathione production. The results of metabolic flux and metabolomic analyses suggested that the conversion of O-acetylserine to cysteine is the rate-limiting step in glutathione production by KG06. The use of sodium thiosulfate largely overcame this limitation, increasing the glutathione titer to 22.0 g/L, which is, to our knowledge, the highest titer reported to date in the literature. This study is the first report of glutathione fermentation without adding cysteine in E. coli. Our findings provide a great potential of E. coli fermentation process for the industrial production of glutathione.

Suspension Culture System for Isolating Cancer Spheroids using Enzymatically Synthesized Cellulose Oligomers.

Isolating cancer cells from tissues and providing an appropriate culture environment are important for a better understanding of cancer behavior. Although various three-dimensional (3D) cell culture systems have been developed, techniques for collecting high-purity spheroids without strong stimulation are required. Herein, we report a 3D cell culture system for the isolation of cancer spheroids using enzymatically synthesized cellulose oligomers (COs) and demonstrate that this system isolates only cancer spheroids under coculture conditions with normal cells. CO suspensions in a serum-containing cell culture medium were prepared to suspend cells without settling. High-purity cancer spheroids could be separated by filtration without strong stimulation because the COs exhibited antibiofouling properties and a viscosity comparable to that of the culture medium. When human hepatocellular carcinoma (HepG2) cells, a model for cancer cells, were cultured in the CO suspensions, they proliferated clonally and efficiently with time. In addition, only developed cancer spheroids from HepG2 cells were collected in the presence of normal cells by using a mesh filter with an appropriate pore size. These results indicate that this approach has potential applications in basic cancer research and cancer drug screening.

Characterization of polypropyleneimine as an alternative transfection reagent.

Polypropyleneimine (PPI) was examined as a transfection reagent comparing with most widely used polymer, polyethyleneimine (PEI). PPI had better responsiveness to the endosomal pH and showed more condensation ability of plasmid DNA than PEI. Although the cytotoxicity of PPI was somewhat higher than PEI, the transfection efficacy of PPI was comparable with PEI or higher than PEI in some cell line. Thus, PPI would be an alternative transfection reagent.

Efficacy of cEEG and hepatic function to diagnose early acute encephalopathy.

BACKGROUND: Early treatment may improve the prognosis of acute encephalopathy (AE). However, methods for early diagnosis have not yet been established. In this paper, we examined methods for the early diagnosis of AE. METHODS: We extracted data on patients with febrile status epilepticus from the electronic medical records in our department between March 2016 and April 2021. Among these, 79 patients who underwent continuous electroencephalography (cEEG) were included in this study. Patients who exhibited psychomotor retardation or abnormal brain magnetic resonance imaging findings were assigned to Group E (n = 20), and the remaining patients were the control group (Group C, n = 59). The following tests were compared retrospectively between these two groups on admission: cEEG, serum hepatic function tests, and blood coagulation tests. RESULTS: The percentage of patients who exhibited high-amplitude slow waves or flat waves on cEEG at the time of admission was statistically significantly higher in Group E than in Group C (p < 0.01). Moreover, the percentage of patients whose high-amplitude slow waves or flat brain waves on admission disappeared within 6 h after an initial episode of convulsion was statistically significantly lower in Group E than in Group C (p < 0.01). Furthermore, all the items in the coagulation and the hepatic function tests were statistically significantly different in Group E from those in Group C (p < 0.05). CONCLUSION: These results showed that cEEG together with hepatic function and coagulation tests may be useful for the differential diagnosis of AE.

Maximum knee extension velocity without external load is a stronger determinant of gait function than quadriceps strength in the early postoperative period following total knee arthroplasty.

OBJECTIVE: Quadriceps weakness is considered the primary determinant of gait function after total knee arthroplasty (TKA). However, many patients have shown a gap in improvement trends between gait function and quadriceps strength in clinical situations. Factors other than quadriceps strength in the recovery of gait function after TKA may be essential factors. Because muscle power is a more influential determinant of gait function than muscle strength, the maximum knee extension velocity without external load may be a critical parameter of gait function in patients with TKA. This study aimed to identify the importance of knee extension velocity in determining the gait function early after TKA by comparing the quadriceps strength. METHODS: This prospective observational study was conducted in four acute care hospitals. Patients scheduled for unilateral TKA were recruited (n = 186; age, 75.9 ± 6.6 years; 43 males and 143 females). Knee extension velocity was defined as the angular velocity of knee extension without external load as quickly as possible in a seated position. Bilateral knee function (knee extension velocity and quadriceps strength), lateral knee function (pain and range of motion), and gait function (gait speed and Timed Up and Go test (TUG)) were evaluated before and at 2 and 3 weeks after TKA. RESULTS: Both bilateral knee extension velocities and bilateral quadriceps strengths were significantly correlated with gait function. The knee extension velocity on the operation side was the strongest predictor of gait function at all time points in multiple regression analysis. CONCLUSION: These findings identified knee extension velocity on the operation side to be a more influential determinant of gait function than impairments in quadriceps strength. Therefore, training that focuses on knee extension velocity may be recommended as part of the rehabilitation program in the early postoperative period following TKA. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR) UMIN000020036.

Enrichment of Cancer Cells Based on Antibody-Free Selective Cell Adhesion.

Blood-compatible and cell-adhering polymer materials are extremely useful for regenerative medicine and disease diagnosis. (Meth)acryl polymers with high hydrophilicity have been widely used in industries, and attempts to apply these polymers in the medical field are frequently reported. We focused on crosslinked polymer films prepared using bifunctional monomers, which are widely used as coating materials, and attempted to alter the cell adhesion behavior while maintaining blood compatibility by changing the chemical structure of the crosslinker. Four bifunctional monomers were studied, three of which were found to be blood-compatible polymers and to suppress platelet adhesion. The adhesion behavior of cancer cells to polymer films varied; moreover, the cancer model cells MCF-7 [EpCAM(+)] and MDA-MB-231 [EpCAM (-)], with different expression levels of epithelial cell adhesion molecule (EpCAM), showed distinct adhesion behavior for each material. We suggest that a combination of these materials has the potential to selectively capture and enrich highly metastatic cancer cells.

Conformable microneedle pH sensors via the integration of two different siloxane polymers for mapping peripheral artery disease.

Flexible microneedles are important tools that allow access to the inside of biological tissue from the outside without surgery. However, it had been hard to realize microneedle sensor arrays on flexible substrates because of the difficulty of attaining a needle with a high Young's modulus for a selected area on a thin or soft substrate. In this work, we developed a microneedle sensor on a hybrid substrate based on high Young's modulus epoxy siloxane for the microneedles and low Young's modulus polydimethylsiloxane for the conformable substrate. Polyaniline was deposited on the microneedle for pH sensing. The mechanical durability of the device was assessed by insertion into pig skin 1000 times. Last, the flexible microneedle pH sensors showed their utility for monitoring pH distribution in rats in a peripheral artery diseases model.

Effect of bound water content on cell adhesion strength to water-insoluble polymers.

Adhesion of cells on biomaterials plays an essential role in modulating cellular functions. Although hydration of biomaterials occurs under biological conditions, it is challenging to systematically evaluate the correlation of hydrated water content in biomaterials with the cell adhesion strength. In this report, we investigated the effect of bound water content on the adhesion strength of cells on poly(2-methoxyethyl acrylate) (PMEA) analogue substrates. Water-insoluble PMEA analogues were synthesized to fabricate substrates with a systemically controlled bound water content. To assess the surface properties of their substrates, contact angle measurement, atomic force microscopy (AFM), and fluorescence measurement were conducted. To reflect the effect of bound water of PMEA analogues, the relationship between the bound water content and cell adhesion behavior was evaluated under serum-free condition. From the single cell force spectrometry (SCFS) and microscopic analysis, it revealed that the increment of bound water content on the substrates decreased cell adhesion strength and cell spreading on the substrates. The bound water content exhibited a good correlation with adhesion strength, spreading area, circularity, and aspect ratio of cells. Our findings indicate that the bound water content could contribute to the development of a novel biomaterial and evaluation of cell behaviors on biomaterials. STATEMENT OF SIGNIFICANCE: For coordinating cell functions, such as growth, mobility, and differentiation, modulating the adhesion strength between cells and their environments is important. Although the hydration to biomaterials has been reported to be closely related to a antifouling property, the effect of hydration water on the cell adhesion behavior is not well understood. We present the first demonstration of essential relationship between cell adhesion strength and hydrated water on a biomaterials surface using the water-insoluble polymers with different hydrated water content. The results reveal that the hydrated water content of polymer substrates strong correlation with adhesion strength of cells. Collectively, the hydrated water content of the biomaterials will be a predominant factor affecting the cell adhesion strength and behavior.

Poly(tertiary amide acrylate) Copolymers Inspired by Poly(2-oxazoline)s: Their Blood Compatibility and Hydration States.

Modifying the side chain of poly(meth)acrylate with moieties originating from biocompatible polymers can be an effective method for developing novel blood-compatible polymers. Inspired by biocompatible poly(2-methyl-2-oxazoline) (PMeOx) and poly(2-ethyl-2-oxazoline) (PEtOx), four water-soluble poly(tertiary amide acylate) analogues bearing a pendant tertiary amide were synthesized. The results of hemolysis and cell viability tests showed that all the poly(tertiary amide acylate) analogues were compatible with red blood cells, HeLa cells, and normal human dermal fibroblasts as PMeOx or PEtOx. Among the four poly(tertiary amide acylate) analogues, poly[2-(N-methylpropionamido)ethyl acrylate] (PPEA) and poly[2-(N-ethylacetamido)ethyl acrylate] (PEAE) showed thermosensitivity in aqueous solution; especially, PPEA (10 mg mL-1) exhibited a lower critical solution temperature of 37 °C. Water-insoluble copolymers were prepared to investigate the possibility of applying these synthesized polymers as blood-compatible coatings. The poly[n-butyl methacrylate70-co-2-(N-methylacetamido)ethyl methacrylate30] (coPAEM) coatings significantly suppressed plasma protein adsorption, denaturation degree of adsorbed fibrinogen, and platelet adhesion. Intermediate water (IW), whose content can generally indicate the blood compatibility of polymers, was found in all hydrated homopolymers and copolymers by differential scanning calorimetry. The present work demonstrated that the tertiary amide moiety in the side chain of poly(meth)acrylate was an effective contributor to blood compatibility and IW.

Effects of Side-Chain Spacing and Length on Hydration States of Poly(2-methoxyethyl acrylate) Analogues: A Molecular Dynamics Study.

Hydration states of polymers are known to directly influence the adsorption of biomolecules. Particularly, intermediate water (IW) has been found able to prevent protein adsorption. Experimental studies have examined the IW content and nonthrombogenicity of poly(2-methoxyethyl acrylate) analogues with different side-chain spacings and lengths, which are HPx (x is the number of backbone carbons in a monomer) and PMCyA (y is the number of carbons in-between ester and ether oxygens of the side-chain) series, respectively. HPx was reported to possess more IW content but lower nonthrombogenicity compared to PMCyA with analogous composition. To understand the reason for the conflict, molecular dynamics simulations were conducted to elucidate the difference in the properties between the HPx and PMCyA. Simulation results showed that the presence of more methylene groups in the side chain more effectively prohibits water penetration in the polymer than those in the polymer backbone, causing a lower IW content in the PMCyA. At a high water content, the methoxy oxygen in the shorter side chain of the HPx cannot effectively bind water compared to that in the PMCyA side chain. HPx side chains may have more room to contact with molecules other than water (e.g., proteins), causing experimentally less nonthrombogenicity of HPx than that of PMCyA. In summary, theoretical simulations successfully explained the difference in the effects of side-chain spacing and length in atomistic scale.

Engineering of Aeromonas caviae Polyhydroxyalkanoate Synthase Through Site-Directed Mutagenesis for Enhanced Polymerization of the 3-Hydroxyhexanoate Unit.

Polyhydroxyalkanoate (PHA) synthase is an enzyme that polymerizes the acyl group of hydroxyacyl-coenzyme A (CoA) substrates. Aeromonas caviae PHA synthase (PhaCAc) is an important biocatalyst for the synthesis of a useful PHA copolymer, poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)]. Previously, a PhaCAc mutant with double mutations in asparagine 149 (replaced by serine [N149S]) and aspartate 171 (replaced by glycine [D171G]) was generated to synthesize a 3HHx-rich P(3HB-co-3HHx) and was named PhaCAc NSDG. In this study, to further increase the 3HHx fraction in biosynthesized PHA, PhaCAc was engineered based on the three-dimensional structural information of PHA synthases. First, a homology model of PhaCAc was built to target the residues for site-directed mutagenesis. Three residues, namely tyrosine 318 (Y318), serine 389 (S389), and leucine 436 (L436), were predicted to be involved in substrate recognition by PhaCAc. These PhaCAc NSDG residues were replaced with other amino acids, and the resulting triple mutants were expressed in the engineered strain of Ralstonia eutropha for application in PHA biosynthesis from palm kernel oil. The S389T mutation allowed the synthesis of P(3HB-co-3HHx) with an increased 3HHx fraction without a significant reduction in PHA yield. Thus, a new workhorse enzyme was successfully engineered for the biosynthesis of a higher 3HHx-fraction polymer.

A fully covered self-expandable metallic stent coated with poly (2-methoxyethyl acrylate) and its derivative: In vitro evaluation of early-stage biliary sludge formation inhibition.

The adhesion and deformation behavior of proteins at the inner surface of fully covered, self-expandable metallic stents coated with biocompatible polymers, poly(2-methoxyethyl acrylate) (PMEA) and poly(3-methoxypropyl acrylate) (PMC3A), were analyzed. Model bile solution, proteins, and bacteria were used to unravel the inhibitory ability of the polymer coatings. Adsorbance of proteins and adherence of bacteria were both strongly inhibited by the polymer coatings. Circulation tests were performed under clinical conditions using human bile from patients. Adsorption/deformation of proteins and early-stage sludge formation were inhibited on stent surfaces coated with PMEA derivatives. The present study revealed that early-stage biliary sludge formation on PMEA- and PMC3A-coated stents was suppressed due to the strong resistance of the polymers to protein adsorption/deformation, brought about by intermediate water in hydrated polymer coatings, which is not present in conventional coating materials, such as silicone and polyurethane.

A randomized, double-blind, phase II study of oral histone deacetylase inhibitor resminostat plus S-1 versus placebo plus S-1 in biliary tract cancers previously treated with gemcitabine plus platinum-based chemotherapy.

PURPOSE: Effective second-line chemotherapy options are limited in treating advanced biliary tract cancers (BTCs). Resminostat is an oral histone deacetylase inhibitor. Such inhibitors increase sensitivity to fluorouracil, the active form of S-1. In the phase I study, addition of resminostat to S-1 was suggested to have promising efficacy for pre-treated BTCs. This study investigated the efficacy and safety of resminostat plus S-1 in second-line therapy for BTCs. METHODS: Patients were randomly assigned to receive resminostat or placebo (200 mg orally per day; days 1-5 and 8-12) and S-1 group (80-120 mg orally per day by body surface area; days 1-14) over a 21-day cycle. The primary endpoint was progression-free survival (PFS). Secondary endpoints comprised overall survival (OS), response rate (RR), disease control rate (DCR), and safety. RESULTS: Among 101 patients enrolled, 50 received resminostat+S-1 and 51 received placebo+S-1. Median PFS was 2.9 months for resminostat+S-1 vs. 3.0 months for placebo+S-1 (HR: 1.154, 95% CI: 0.759-1.757, p = 0.502); median OS was 7.8 months vs. 7.5 months, respectively (HR: 1.049, 95% CI: 0.653-1.684, p = 0.834); the RR and DCR were 6.0% vs. 9.8% and 70.0% vs. 78.4%, respectively. Treatment-related adverse events (TrAEs) of grade ≥ 3 occurring more frequently (≥10% difference) in the resminostat+S-1 than in the placebo+S-1 comprised platelet count decreased (18.0% vs. 2.0%) and decreased appetite (16.0% vs. 2.0%). CONCLUSIONS: Resminostat plus S-1 therapy improved neither PFS nor OS for patients with pre-treated BTCs. Addition of resminostat to S-1 was associated with higher incidence of TrAEs, but these were manageable (JapicCTI-183883).

Molecular Dynamics Study on the Water Mobility and Side-Chain Flexibility of Hydrated Poly(ω-methoxyalkyl acrylate)s.

Intermediate water (IW) is known to play an important role in the antifouling property of biocompatible polymers. However, how IW prevents protein adsorption is still unclear. To understand the role of IW in the antifouling mechanism, molecular dynamics simulation was used to investigate the dynamic properties of water and side-chains for hydrated poly(ω-methoxyalkyl acrylate)s (PMCxA, where x indicates the number of methylene carbons) with x = 1-6 and poly(n-butyl acrylate) (PBA) in this study. Since the polymers uptake more water than their equilibrium water content (EWC) at the polymer/water interface, we analyzed the hydrated polymers at a water content higher than that of EWC. It was found that the water molecules interacting with one polymer oxygen atom (BW1), of which most are IW molecules, in PMC2A exhibit the lowest mobility, while those in PBA and PMC1A show a higher mobility. The result was consistent with the expectation that the biocompatible polymer with a long-resident hydration layer possesses good antifouling property. Through the detailed analysis of side-chain binding with three different types of BW1 molecules, we found that the amount of side-chains simultaneously interacting with two BW1 molecules, which exhibit the highest flexibility among the three kinds of side-chains, is the lowest for PMC1A. The high mobility of BW1 is thus suggested as the main factor for the poor protein adsorption resistance of PMC1A even though it possesses enough IW content and relatively flexible side-chains. Contrarily, a maximum amount of side-chains simultaneously interacting with two BW1 molecules was found in the hydrated PMC3A. The moderate side-chain length of PMC3A allows side-chains to simultaneously interact with two BW1 molecules and minimizes the hydrophobic part attractively interacting with a protein at the polymer/water interface. The unique structure of PMC3A may be the reason causing the best protein adsorption resistance among the PMCxAs.

Difference in pyruvic acid metabolism between neonatal and adult mouse lungs exposed to hyperoxia.

OBJECTIVE: Neonatal lungs are more tolerant to hyperoxic injury than are adult lungs. This study investigated differences in the response to hyperoxic exposure between neonatal and adult mouse lungs using metabolomics analysis with capillary electrophoresis time-of-flight mass spectrometry (CE- TOFMS). METHODS: Neonatal and adult mice were exposed to 21% or 95% O2 for four days. Subsequently, lung tissue samples were collected and analyzed by CE-TOFMS. Pyruvate dehydrogenase (PDH) enzyme activity was determined using a microplate assay kit. PDH kinase (Pdk) 1, Pdk2, Pdk3, and Pdk4 mRNA expression levels were determined using quantitative reverse transcription-polymerase chain reaction. Pdk4 protein expression was quantified by Western blotting and Pdk4 protein localization was evaluated by immunohistochemistry. RESULTS: Levels of 3-phosphoglyceric acid, 2-phosphoglyceric acid, phosphoenolpyruvic acid, and lactic acid were significantly elevated in the lungs of hyperoxia-exposed versus normoxia-exposed adult mice, whereas no significant differences were observed with hyperoxia exposure in neonatal mice. PDH activity was reduced in the lungs of adult mice only. Pdk4 mRNA expression levels after hyperoxic exposure were significantly elevated in adult mice compared with that in neonatal mice. Conversely, gene expression levels of Pdk1, Pdk2, and Pdk3 did not differ after hyperoxic exposure in either neonatal or adult mice. Pdk4 protein levels were also significantly increased in adult mouse lungs exposed to hyperoxia and were localized mainly to the epithelium of terminal bronchiole. CONCLUSIONS: Specific metabolites associated with glycolysis and gluconeogenesis were altered after hyperoxia exposure in the lungs of adult mice, but not in neonates, which was likely a result of reduced PDH activity due to Pdk4 mRNA upregulation under hyperoxia.

Blood-Compatible Poly(2-methoxyethyl acrylate) Induces Blebbing-like Phenomenon and Promotes Viability of Tumor Cells in Serum-Free Medium.

Circulating tumor cells (CTCs) are highly related to tumor metastasis and an effective technique of detecting/isolating CTCs has been expected to be established for tumor treatments. Previously, we reported that platelets cannot adhere but tumor cells can adhere on poly(2-methoxyethyl acrylate) (PMEA) substrate. In this study, we report that cell viability of human fibrosarcoma (HT-1080) cells was promoted on PMEA substrate in serum-free medium. The significant blebbing-like phenomenon and spontaneous formation of cell aggregation were observed on PMEA substrate. Moreover, cell viability was promoted by activation of Akt signaling pathway via N-cadherin-mediated cell-cell contact. These results suggest that not only capture efficiency and purity but also high cell viability of CTCs can be accomplished by using PMEA substrate. PMEA substrate can be a promising candidate for medical applications such as in vitro screening of anticancer drugs and is an excellent platform for studies and diagnoses of tumor migration and metastasis.

Understanding the Effect of Hydration on the Bio-inert Properties of 2-Hydroxyethyl Methacrylate Copolymers with Small Amounts of Amino- or/and Fluorine-Containing Monomers.

Materials exhibiting "bio-inert properties" are essential for developing medical devices because they are less recognized as foreign substances by proteins and cells in the living body. We have reported that the presence of intermediate water (IW) with the water molecules loosely bound to a polymer is a useful index of the bio-inertness of materials. Here, we analyzed the hydration state and the responses to biomolecules of poly(2-hydroxyethyl methacrylate) (PHEMA) copolymers including small amounts of 2-(dimethylamino)ethyl methacrylate (DMAEMA) (N-series) or/and 2,2,2-trifluoroethyl methacrylate (TFEMA) (F-series). The hydration structure was analyzed by differential scanning calorimetry (DSC), the molecular mobility of the produced copolymers by temperature derivative of DSC (DDSC), and the water mobility by solid 1H pulse nuclear magnetic resonance (NMR). Although the homopolymers did not show bio-inert properties, the binary and ternary PHEMA copolymers with low comonomer contents showed higher bio-inert properties than those of PHEMA homopolymers. The hydration state of PHEMA was changed by introducing a small amount of comonomers. The mobility of both water molecules and hydrated polymers was changed in the N-series nonfreezing water (NFW) with the water molecules tightly bound to a polymer and was shifted to high-mobility IW and free water (FW) with the water molecules scarcely bound to a polymer. On the other hand, in the F-series, FW turned to IW and NFW. Additionally, a synergetic effect was postulated when both comonomers coexist in the copolymers of HEMA, which was expressed by widening the temperature range of cold crystallization, contributing to further improvement of the bio-inert properties.

Elucidating the Feature of Intermediate Water in Hydrated Poly(ω-methoxyalkyl acrylate)s by Molecular Dynamics Simulation and Differential Scanning Calorimetry Measurement.

Intermediate water (IW) has been reported to play an important role in nonthrombogenicity of biomaterials. However, clear insights into the IW in the hydrated polymer are still debated. In this study, a series of molecular dynamics simulations was performed to identify the IW structure in hydrated poly(ω-methoxyalkyl acrylate)s (PMCxAs, where x indicates the number of methylene carbons) with x = 1-6. Through the quantitative comparison with experimental measurements, IW molecules were suggested to mainly come from the water interacting with an oxygen atom of the polymers, while most of the nonfreezing water (NFW) molecules corresponded to the water interacting with two polymer oxygen atoms. In addition, the IW molecules were found to effectively enhance the flexibility of the PMCxA side chains in comparison with the NFW molecules. The variations of the saturated IW content and the side-chain flexibility with the methylene carbon chain length of PMCxA were also found to be correlated with the experimental nonthrombogenicity of PMCxA, suggesting that the polymer with the more saturated IW content and higher chain flexibility possesses better nonthrombogenicity. Furthermore, through the analyses of the interplays between the IW and polymer and between IW and its adjacent water, we found that the presence of the unique interaction between IW and its adjacent water in the hydrated poly(2-methoxyethyl acrylate) (PMEA) is the main factor causing different cold crystallization behaviors of PMEA from the other PMCxAs rather than the interaction between water and the PMCxA matrix. The findings will be useful in the development of new nonthrombogenic materials.

Majorana Multipole Response of Topological Superconductors.

In contrast to elementary Majorana particles, emergent Majorana fermions (MFs) in condensed-matter systems may have electromagnetic multipoles. We developed a general theory of magnetic multipoles for helical MFs on time-reversal-invariant superconductors. The results show that the multipole response is governed by crystal symmetry, and that a one-to-one correspondence exists between the symmetry of Cooper pairs and the representation of magnetic multipoles under crystal symmetry. The latter property provides a way to identify unconventional pairing symmetry via the magnetic response of helical MFs. We also find that most helical MFs exhibit a magnetic-dipole response, but those on superconductors with spin-3/2 electrons may display a magnetic-octupole response in leading order, which uniquely characterizes high-spin superconductors. Detection of such an octupole response provides direct evidence of high-spin superconductivity, such as in half-Heusler superconductors.