Deformation Behavior of Body-Centered Cubic Lattice in Polymers.

A body-centered cubic (BCC) lattice is a crystal unit cell structure observed in metals, inorganics, and polymers. The deformation behavior of the BCC lattice in metals has been well elucidated, whereas that of polymers remains unclear. We used a microphase-separated copolymer with randomly oriented grains wherein spherical phases are packed in the BCC lattice. The copolymer showed affine deformation under a strain of 1.8, which is much larger than that observed for metals, followed by spectacular rearrangement and "push-and-shove" deformation. To the best of our knowledge, these structural changes have not yet been observed in metals. These differences in the behavior of metals and polymers arise depending on the contact state of the spherical phases.

Specific deformation behavior of isotactic polypropylene films under a multiaxial stress field.

The specific deformation behavior of crystalline polymer films, namely unoriented crystallized isotactic polypropylene (it PP) films, was investigated under a multiaxial stress field. Changes in the aggregation structure of the films were investigated during the bulge deformation process using in situ small-angle X-ray scattering, wide-angle X-ray diffraction (WAXD) measurements, and polarized high-speed-camera observations. The films had a thickness of approximately 10 µm. The it PP films were fixed at the hole of a plate, then bulge deformation was applied using N2 or He gas pressure, and stress-strain curves were then calculated from the applied pressure and bulge height. Yielding was observed in the stress-strain curves. Below the yield point, in situ WAXD measurements revealed that the crystal lattice expanded isotropically at the center, edge, and bottom of the bulge hole. Above the yield point, a craze started to form slightly near the center, and crazes formed in various directions with a further increase in strain, while the crystal lattice expanded uniaxially along the circumference at the edge and bottom. Crazes oriented in various directions merged and lost birefringence, indicating a change to the isotropic orientation. The different directions of the crazes indicated several directions of stress. In other words, even if multiaxial deformation is applied to a crystalline it PP film, the string-shaped crystalline polymer chain structure produces local anisotropic uniaxial stress.

Primary Aldosteronism with Parathyroid Hormone Elevation: A Single-center Retrospective Study.

Objective Primary aldosteronism (PA) is a major cause of secondary hypertension. The association between PA and other hormone disorders is unclear. The present study aimed to evaluate whether the parathyroid hormone (PTH) value is associated with PA subtypes or specific treatments. Methods We enrolled 135 patients with PA who had their PTH value measured before undergoing a specific treatment. We evaluated whether PTH value is associated with PA subtypes or with specific treatments. The present study is a single-center retrospective study (2011-2018). Results Our study showed that, among the patients with PA, the proportion of those with PTH elevation was >30%. The PTH value was significantly correlated with both the basal plasma aldosterone concentration (PAC) and PAC after a captopril challenge test. However, the PTH value was not significantly different between the patients with unilateral and bilateral PA. We observed that the serum PTH value decreased after treatment of PA with unilateral adrenalectomy or mineralocorticoid receptor antagonists. Conclusion Our findings suggest that the PTH value in PA patients might be associated with the autonomous production of aldosterone. However, there was no correlation between the PTH value and PA subtypes in our study. Additionally, our study showed that targeted treatment for PA may lead to a decrease in the serum PTH levels. Hence, the PTH value could potentially be used as an index for measuring the suitability for PA treatment.

High frequency of type 2 diabetes and impaired glucose tolerance in Japanese subjects with the angiopoietin-like protein 8 R59W variant.

BACKGROUND: Angiopoietin-like protein 8 (ANGPTL8) is considered to be metabolically multifunctional. One notable function still to be elucidated definitively is a betatrophic role in protecting and preserving pancreatic beta-cell function. There is, however, a paucity of data regarding the role of ANGPTL8 in the etiology of type 2 diabetes (T2D), but some findings of human research have suggested the potential for significant involvement. OBJECTIVE: To examine the frequency of T2D and impaired glucose tolerance (IGT) in Japanese subjects with the ANGPTL8 R59W variant. METHODS: ANGPTL8 R59W (Rs2278426, c.194C > T) was determined by polymerase chain reaction-restriction fragment length polymorphism using the restriction enzyme FokI in 797 consecutive Japanese individuals. Subjects with triglyceride levels greater than or equal to 150 mg/dL were considered to be hypertriglyceridemic. RESULTS: Genotype frequencies of ANGPTL8 R59W were as follows: wild-type RR (C/C) 53.5%, RW (C/T) 36.6%, and WW (T/T) 9.9%. T2D and IGT were significantly prevalent in WW and RW subjects relative to RR among all 797 subjects (P = .0138) and also in hypertriglyceridemic subjects (P = .0015). In multiple logistic regression models for the existence of T2D and IGT in hypertriglyceridemic subjects, the odds ratio for heterozygote RW and homozygote WW genotypes to wild-type RR was 2.406 (P = .0017) after controlling the risk factors of age, gender, and body mass index as covariates. CONCLUSIONS: The frequency of ANGPTL8 R59W is significantly higher in Japanese subjects than in other ethnic groups. The rates of T2D and IGT were greater in subjects with the R59W variant. These findings indicate that ANGPTL8 is a participant in diabetes and a potential therapeutic target for T2D prevention, especially in East Asians.

In situ synchrotron radiation X-ray diffraction studies on molecular aggregation structure of nylon 12 films during bulge testing.

It is desirable to establish a method for evaluating mechanical properties, such as modulus and strength, of micrometer and sub-micrometer thick polymer films. Bulge tests, where bulge deformation is imposed on films by the pressure of an inert gas, are suitable for satisfying this demand. However, very few studies on polymer films exist in the literature. In this study, bulge testing equipment for in situ synchrotron radiation wide-angle X-ray diffraction (WAXD) measurements is designed and used to study the relationship between the molecular aggregation structure and the mechanical properties of a crystalline nylon 12 (Ny12) film during bulge testing. Isothermally crystallized and quenched Ny12 films exhibited stress-strain curves similar to those obtained by conventional uniaxial elongation. In situ WAXD measurements during bulge testing revealed that the lattice extension of the crystallites is clearly dependent on crystallinity. Concretely, crystallites in the isothermally crystallized film show higher elastic properties than those in the quenched one. The results of the molecular aggregation structure, including the crystal structure and the amorphous chain surrounding the crystallites, of the films during bulge deformation firstly obtained in this study must be useful for designing toughened polymer films.

Effect of sodium glucose cotransporter 2 inhibitors on obstructive sleep apnea in patients with type 2 diabetes.

Obstructive sleep apnea syndrome (OSAS) is often associated with metabolic disorders such as obesity and type 2 diabetes and may contribute to cardiovascular events. A novel class of antidiabetic drugs, the sodium glucose cotransporter 2 inhibitors (SGLT2i) reduce body weight (BW), although there is limited data on their impact on OSAS. We therefore evaluated the effect of SGLT2i on OSAS in patients with type 2 diabetes. The presented study was a retrospective design in 18 patients with type 2 diabetes with OSAS (4 males, age range 39-81 yr) administrated a SGLT2i. HbA1c, BW, body mass index (BMI), blood pressure (BP) and apnea hypopnea index (AHI) were evaluated before and after SGLT2i administration. The relationships between the reduction in AHI and the other variables were examined using Pearson correlation analysis. We have got result that SGLT2i reduced AHI from 31.9 ± 18.0 to 18.8 ± 11.5 events per hr (p = 0.003). HbA1c, BW and BMI decreased significantly, whereas BP did not. The Pearson correlation analysis showed a significant relationship between the reduction in AHI and pre-administration of AHI. In conclusion, SGLT2i reduced not only HbA1c, BW and BMI but also AHI significantly and therefore has potential as an effective treatment of OSAS.

Biobased Polymer Coating Using Catechol Derivative Urushiol.

We have investigated the mechanism of the superior mechanical robustness of coated thin films of the catechol derivative urushiol. We synthesized hydrogenated urushiol (h-urushiol) by hydrogenating the double bonds in the long alkyl side chain of urushiol, and the physical properties of thin films of mixtures of urushiol and h-urushiol were evaluated. Atomic force microscopy observations revealed that these coated thin films have a homogeneous surface with no phase separation, regardless of the h-urushiol content, arising from the similarity of the chemical structures. The films showed good adhesive properties because the adhesion originates from the catechol structure. In contrast, curing time depended strongly upon the h-urushiol content. The curing of the h-urushiol thin film took 12 h, whereas the urushiol thin film was cured within 10 min. Moreover, the strain-induced elastic buckling instability for mechanical measurements test and the bulge test confirmed that the increase in the h-urushiol content decreased the mechanical strength. Because the double bonds in the urushiol side chain contribute to forming the highly cross-linked structure, the lack of double bonds in h-urushiol resulted in the slow curing and low mechanical strength. Interestingly, the mechanical robustness started to increase over 80 mol % h-urushiol. The saturated long alkyl side chain of h-urushiol faced the surface, and the regular structure of the uniform side chain may improve the mechanical properties of the coated film. Our results will help to develop biomimetic catechol-based coatings.

Spray-assisted nanocoating of the biobased material urushiol.

We have demonstrated the spray-assisted coating of the catechol derivative, urushiol. Spraying a mixture of urushiol and iron(II) acetate formed a uniform coating about 10 nm thick, as confirmed by AFM observations. XPS measurements revealed that various substrates, including polyolefins and thermosetting resins, were successfully coated with urushiol. The coating showed good solvent tolerance and coating adhesion after baking at 100 °C for 10 min or after aerobic oxidation for several days. Interestingly, quartz crystal microbalance (QCM) measurements and strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) revealed that density and Young's modulus of the spray-assisted nanocoatings were higher than those of spray-coated samples. Moreover, the coating was uninvolved in physical properties except surface properties, as demonstrated by several experiments. Because urushiol is a promising biobased material, our unique spray-assisted coating technique could provide a general approach for material-independent surface modification techniques that are environmentally sustainable.

Surface functionalization by decal-like transfer of thermally cross-linked urushiol thin films.

We have demonstrated surface functionalization through the decal-like transfer of thermally cross-linked urushiol thin films onto various substrates. Tensile adhesive strength measurements showed that the film adheres strongly to the surface of various substrates including chemically inert materials, such as polyolefins and thermosetting resins, because of the properties of urushiol. Furthermore, the highly cross-linked structure of urushiol made the films mechanically robust. These two properties allowed the fabrication of practicable thin films for indirect surface modification. Actually, the robust thin film served as a scaffold for an Au thin film, which was then bound to various substrates. Surface-texturing of nanodecal was also demonstrated as an application aspects.

Scaffold for growing dense polymer brushes from a versatile substrate.

We have demonstrated a universal approach to growing polymer brushes from various substrates. Urushiol was mixed with initiator-containing catechol, and it was spin-coated or cast on various substrates. Because urushiol is strongly adhered to various substrates, the thin film can serve as a general scaffold for grafting polymer brushes from various substrates. Note that the film was formed even onto the surface of polyolefins and thermosetting resins that are known as chemically inert materials to functionalize the surface. Moreover, the initiator-immobilized scaffold showed mechanical robustness and chemical inertness because of the flexible long unsaturated hydrocarbon side chain of urushiol. After the grafting of polyelectrolyte PMTAC polymer brushes, the material obtained exhibited hydrophilicity, typical of PMTAC. The concept shown here could provide a general approach for grafting practical polymer brushes from various substrates.

Robust liquid marbles stabilized with surface-modified halloysite nanotubes.

We have demonstrated the fabrication of fluorine-free liquid marbles from halloysite nanotube. Halloysite is a naturally occurring inorganic nanotube that has a high aspect ratio, and the surface was modified with octadecyltrimethoxysilane. The surface-modified halloysite formed pincushion agglomerates on the surface of the liquid droplets, which create superhydrophobic surface similar to that of the plant gall surface prepared by aphids. As a result, the liquid marbles showed high mechanical strength upon impact without the use of low surface energy fluoroalkyl or fluorine-modified materials. Our results suggest a new strategy for designing novel materials for liquid marbles inspired by nature.

Chemical evidence for the synergistic effect of a cysteinyl thiol on the antioxidant activity of caffeic and dihydrocaffeic esters.

Antioxidant activity of methyl caffeate and methyl dihydrocaffeate in the presence of a cysteinyl thiol was measured in an azo-initiator-induced lipid oxidation system. The coexistence of the thiol was observed to display a synergistic effect on the antioxidant activity of both caffeates. The synergism was observed mainly with respect to the elongation of the induction period, rather than the inhibition rate for lipid oxidation. For methyl caffeate, the maximum elongation of the induction period was observed in the presence of more than two equivalents of the thiol, whereas the maximum effect on the activity of methyl dihydrocaffeate was observed in the presence of more than three equivalents of the thiol. These synergistic effects were analysed by high-performance liquid chromatography and liquid chromatography-mass spectrometry analyses of the intermediates produced during the antioxidation period. The analytical results clarified that the mono-thiol adduct of methyl caffeate and the mono- and di-thiol adducts of methyl dihydrocaffeate contributed to the synergism in the antioxidant activity of both caffeates.

Concealing surface topography by attachment of nanometer-thick film.

Concealing of surface topology of substrates by decal-like attachment of nanomembrane is demonstrated. The nanomembrane attachment provides a flat surface on various substrates, including porous substrates, and the surface property such as wettability was changed to that of the nanomembrane. The monitoring of drying process revealed that a nanomembrane with certain thickness tolerates their flexural deflection during the procedure. Moreover, the supporting position of nanomembranes as well as the physical properties of nanomembranes strongly affected the degree of deflection. The decal-like attachment of nanomembranes shown here is potentially a powerful method for creating a new functional surface that is independent of the topological and chemical properties of the original substrate.

Curcumin: from chemistry to chemistry-based functions.

Curcumin is a yellow pigment found in the spice turmeric and a main functional constituent of the rhizomes of Curcuma longa. The multi-functionality of curcumin has recently attracted much attention in various fields, including food, medicinal, and clinical industries. Three major curcuminoids, curcumin, demethoxycurcumin, and bis-demethoxycurcumin, are distributed in not only Curcuma, but also the Zingiber species; however, distribution of other curcuminoids is very limited in nature. The radical scavenging ability of curcumin, which is the basis of medicinal functionality, is its most important property. Herein, the structures of several rare curcuminoids that have been identified during the past four decades are summarized. Mechanistic studies of the radical trapping stage of curcumin are also comprehensively reviewed, and the studies on antioxidant effects derived from this radical trapping ability of curcuminoids are discussed. Various chemical reactions of curcumin, such as photo-oxidation, enzymatic oxidation, etc. are also summarized. In particular, antioxidation of curcumin in lipid media is introduced as a reaction unique to curcumin.

Chemical interaction between polyphenols and a cysteinyl thiol under radical oxidation conditions.

Chemical interaction between polyphenols and thiols was investigated under radical oxidation conditions using a model cysteinyl thiol derivative, N-benzoylcysteine methyl ester. The radical oxidation was carried out with a stoichiometric amount of 2,2-diphenyl-1-picrylhydrazyl (DPPH), and the decreases in the amounts of polyphenols and the thiol were measured by HPLC analysis. Cross-coupling products between various polyphenols and the thiol were examined by LC-MS in reactions that showed decreases in both the polyphenols and the thiol. The LC-MS results indicated that three phenolic acid esters (methyl caffeate, methyl dihydrocaffeate, and methyl protocatechuate) and six flavonoids (kaempferol, myricetin, luteolin, morin, taxifolin, and catechin) gave corresponding thiol adducts, whereas three polyphenols (methyl ferulate, methyl sinapate, and quercetin) gave only dimers or simple oxidation products without thiol substituents. Thiol adducts of the structurally related compounds methyl caffeate and methyl dihydrocaffeate were isolated, and their chemical structures were determined by NMR analysis. The mechanism for the thiol addition was discussed on the basis of the structures of the products.

Radical scavenging activity of spring mountain herbs in the Shikoku mountain area and identification of antiradical constituents by simple HPLC detection and LC-MS methods.

The functionality of spring mountain herbs, which were collected in the Kajigamori mountain area of Shikoku area in Japan, was investigated in the course of our studies for utilizing local plant resources. The radical scavenging activity of the extracts from seventeen herbs was measured. Among these herbs, two extracts from Polystichym ovato-paleaceum (Japanese name: Tsuyanashiinode) and Sambucus racemosa subsp. sieboldiana (Japanese name: Niwatoko) showed potent DPPH radical scavenging activity. The material evidence for the potent activity of the extracts was studied by a combination of our developed method for detecting antiradical compounds, LC-MS/MS, and enzymatic hydrolysis.

Synthesis of manzacidin A and C: efficient construction of quaternary carbon stereocenters bearing nitrogen substituents.

An efficient synthetic method for stereoselective construction of asymmetric quaternary carbon stereocenters, bearing nitrogen in the form of Boc-protected allyl amines, has been developed. This methodology is employed in the synthesis of marine alkaloids, manzacidin A and C.

Structure and function of the oxidation products of polyphenols and identification of potent lipoxygenase inhibitors from Fe-catalyzed oxidation of resveratrol.

Polyphenols have recently attracted much attention as potent antioxidants and related bioactive substances. These potent antioxidative polyphenols are very oxidizable due to their chemical properties, and their oxidation products must accumulate in the oxidizing foods when they are contained as the active ingredients. In this investigation, 30 polyphenols and related phenolics were oxidized with oxygen in the presence of a catalytic amount of Fe ions. Piceatannol, catechin, epicatechin, hydroxytyrosol, carnosol, and carnosic acid were oxidized very quickly. Sinapic acid, caffeic acid, chlorogenic acid, rosmarinic acid, gallic acid, propyl gallate, α-tocopherol, quercetin, and nordihydroguaiaretic acid were moderately oxidized. Protocatechuic acid, syringic acid, taxifolin, resveratrol, gentisic acid, secoisolariciresinol, and ellagic acid were oxidized for 19-20 days; however, their oxidation was very slow and did not complete. The other phenolics were not oxidized. The obtained oxidation products were next subjected to a lipoxygenase inhibition assay and the results compared to those of the corresponding phenols. Very interestingly, the oxidation product from resveratrol showed a high inhibitory activity, whereas resveratrol itself had no activity and its oxidation efficiency was low. To clarify the inhibition principle of the oxidation product, an LC-MS analysis was carried out on the oxidation product. The analytical results showed that they are the oligomeric and degraded compounds of resveratrol. Among them, the structures of three dimeric compounds were successfully identified, and their activity data clarified that the closed ring dimers were potent lipoxygenase inhibitors, whereas the opened ring dimer was not. It should be noted that resveratrol had almost no lipoxygenase inhibitory activity, contrary to some researchers' findings.

Syntheses of secocyclolignanes and comparative antioxidative activity between secocyclolignane and the dibenzyl type of lignan.

The antioxidative activity of secocyclolignanes was compared with that of the corresponding dibenzyl lignans for the first time. The radical scavenging activity of the secocyclolignanes was weaker than that of the corresponding dibenzyl lignans, the butane diol type showing the highest activity. The butane type of secocyclolignane exhibited the highest antioxidant activity of the unsaturated fatty acid.

A novel ring-expanded product with enhanced tyrosinase inhibitory activity from classical Fe-catalyzed oxidation of rosmarinic acid, a potent antioxidative Lamiaceae polyphenol.

The iron-ion catalyzed oxidation of the ethanol solution of rosmarinic acid, a potent antioxidant polyphenol of Lamiaceae (Labiatae) plants, afforded a highly tyrosinase-inhibitory active product. The structure of the active product in the oxidation product mixture was determined using extensive NMR spectroscopy to have a novel oxygen-containing seven-membered ring system. The formation mechanism of the unique ring structure from the catechol part of the rosmarinic acid was proposed.