Search

Objective: Stress-induced cytotoxicity caused by xenobiotics and endogenous metabolites induces the production of reactive oxygen species and often results in damage to cellular components such as DNA, proteins, and lipids. The cytochrome P450 (CYP) family of enzymes are most abundant in hepatocytes, where they play key roles in regulating cellular stress responses. We aimed to determine the effects of the antioxidant compound, methylsulfonylmethane (MSM), on oxidative stress response, and study the cytochrome P450 family 3 subfamily A (CYP3A) gene expression in fetal horse hepatocytes. Methods: The expression of hepatocyte markers and CYP3A family genes (CYP3A89, CYP3A93, CYP3A94, CYP3A95, CYP3A96, and CYP3A97) were assessed in different organ tissues of the horse and fetal horse liver-derived cells (FHLCs) using quantitative reverse transcription polymerase chain reaction. To elucidate the antioxidant effects of MSM on FHLCs, cell viability, levels of oxidative markers, and gene expression of CYP3A were investigated in H2O2-induced oxidative stress in the presence and absence of MSM. Results: FHLCs exhibited features of liver cells and simultaneously maintained the typical genetic characteristics of normal liver tissue; however, the expression profiles of some liver markers and CYP3A genes, except that of CYP3A93, were different. The expression of CYP3A93 specifically increased after the addition of H2O2 to the culture medium. MSM treatment reduced oxidative stress as well as the expression of CYP3A93 and heme oxygenase 1, an oxidative marker in FHLCs. Conclusion: MSM could reduce oxidative stress and hepatotoxicity in FHLCs by altering CYP3A93 expression and related signaling pathways. [ABSTRACT FROM AUTHOR]

Objective: The study was conducted to investigate variations in the immunophysiological responses to exercise-induced stress in Jeju and Thoroughbred horses. Methods: Blood samples were collected from the jugular veins of adult Jeju (n = 5) and Thoroughbred (n = 5) horses before and after 30 min of exercise. The hematological, biochemical, and immunological profiles of the blood samples were analyzed. Blood smears were stained and observed under a microscope. The concentration of cell-free (cf) DNA in the plasma was determined using real time polymerase chain reaction (PCR). Peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells were separated using Polymorphprep, and the expression of various stress-related and chemokine receptor genes was measured using reverse transcriptase (RT) and real-time PCR. Results: After exercise, Jeju and Thoroughbred horses displayed stress responses with significantly increased rectal temperatures, cortisol levels, and muscle catabolism-associated metabolites. Red blood cell indices were significantly higher in Thoroughbred horses than in Jeju horses after exercise. In addition, exercise-induced stress triggered the formation of neutrophil extracellular traps (NETs) and reduced platelet counts in Jeju horses but not in Thoroughbred horses. Heat shock protein 72 and heat shock protein family A (Hsp70) member 6 expression is rapidly modulated in response to exercise-induced stress in the PBMCs of Jeju horses. The expression of CXC chemokine receptor 4 in PBMCs was higher in Thoroughbred horses than in Jeju horses after exercise. Conclusion: In summary, the different immunophysiological responses of Jeju and Thoroughbred horses explain the differences in the physiological and anatomical properties of the two breeds. The physiology of Thoroughbred horses makes them suitable for racing as they are less sensitive to exercise-induced stress compared to that of Jeju horses. This study provides a basis for investigating the link between exercise-induced stresses and the physiological alteration of horses. Hence, our findings show that some of assessed parameters could be used to determine the endurance performance of horses. [ABSTRACT FROM AUTHOR]

Extracting transient structural information of a solute from time-resolved x-ray diffraction (TRXD) data is not trivial because the signal from a solution contains not only the solute-only term as in the gas phase, but also solvent-related terms. To obtain structural insights, the diffraction signal in q space is often Fourier sine transformed (FT) into r space, and molecular dynamics (MD) simulation-aided signal decomposition into the solute, cage, and solvent terms has so far been indispensable for a clear-cut assignment of structural features. Here we present a convenient method of comparative structural analysis without involving MD simulations by incorporating only isolated-species models for the solute. FT is applied to both the experimental data and candidate isolated-solute models, and comparison of the correlation factors between the experimental FT and the model FTs can distinguish the best candidate among isolated-solute models for the reaction intermediates. The low q region whose influence by solvent-related terms is relatively high can be further excluded, and this mode of truncated Fourier transform (TFT) improves the correlation factors and facilitates the comparison. TFT analysis has been applied to TRXD data on the photodissociation of C2H4I2 in two different solvents (methanol and cyclohexane), HgI2 in methanol, and I3- in methanol excited at 267 nm. The results are consistent with previous conclusions for C2H4I2 in methanol and HgI2 in methanol, and the new TRXD data reveal that the C2H4I transient radical has a bridged structure in cyclohexane and I3- in methanol decomposes into I+I2- upon irradiation at 267 nm. This TFT method should greatly simplify the analysis because it bypasses MD simulations. [ABSTRACT FROM AUTHOR]

A Z-scheme graphitic carbon nitride (g-C3N4)/α-Fe2O3 has been incorporated into a three-dimensional porous graphene aerogel. Graphene aerogels are a promising framework in their use for practical photocatalysis by abundant reaction sites, efficient mass transport of reactants and recyclability through their freestanding framework. At the same time, Z-scheme charge transfer among g-C3N4, α-Fe2O3, and conductive graphene inhibits the rapid recombination of the photoinduced electrons and holes. Ternary g-C3N4/α-Fe2O3/graphene aerogels (CNFGA) showed significantly enhanced photocatalytic activity which demonstrated 4.75 times greater methylene blue degradation and 17.5 times higher photocurrent density than those of exfoliated g-C3N4 under visible light. In addition, CNFGA exhibited a robust photostability with a simple recovery method while showing only a ca. 2% decrease in photocatalytic performance after five cycles. These results suggest that this ternary Z-scheme photocatalyst based on a graphene aerogel has potential use in practical photocatalysis for various environmental applications. [ABSTRACT FROM AUTHOR]

Partially restrained (PR) bolted T-stub connections have been widely used in replacement of established fully restrained (FR) welded connections, which are susceptible to sudden brittle failure. These bolted T-stub connections can permit deformation, easily exceeding the allowable limit without any fracture because they are constructed with a design philosophy whereby the plastic deformation concentrates on bolt fasteners made of ductile steel materials. Thus, the PR bolted connections take advantage of excellent energy dissipation capacity in their moment and rotation behavior. However, a considerable amount of residual deformation may occur at the bolted connection subjected to excessive plastic deformation, thereby requiring additional costs to recover the original configuration. In this study, superelastic shape memory alloy (SMA) bolts, which have a recentering capability upon unloading, are fabricated so as to solve these drawbacks, and utilized by replacing conventional steel bolts in the PR bolted T-stub connection. Instead of the full-scale T-stub connection, simplified T-stub components subjected to axial force are designed on the basis of a basic equilibrium theory that transfers the bending moment from the beam to the column and can be converted into equivalent couple forces acting on the beam flange. The feasible failure modes followed by corresponding response mechanisms are taken into consideration for component design with superelastic SMA bolts. The inelastic behaviors of such T-stub components under cyclic loading are simulated by advanced three-dimensional (3D) finite element (FE) analysis. Finally, this study suggests an optimal design for smart recentering T-stub components with respect to recentering and energy dissipation after observing the FE analysis results. [ABSTRACT FROM AUTHOR]

Background: Social changes related to the elderly in regard to factors such as population, region, cohabitant status and depression incidence, have recently been observed. The aim of our study was to investigate the characteristics of elderly suicide attempters according to these changes. Methods: We retrospectively reviewed the medical records of suicide attempters who visited an Emergency Department between January 2013 and March 2016. Patients were classified into an elderly or non-elderly group. Data included demographic, socioeconomic, and clinical characteristics. The Risk-Rescue Rating Scale (RRRS) and Suicide Intent Scale (SIS) scores were calculated. Results: Of 340 patients, 78 were elderly. Male sex, lower educational and financial status, chronic disease, and depression were more common in the elderly group, while previous history of suicide attempt was more frequent in the non-elderly group. RRRS was higher in the elderly group, while SIS was not significantly different between the 2 groups. Unlike the non-elderly group, no correlation between suicide lethality and intention was found in the elderly group. Multiple logistic regression analysis identified that chronic disease, depression, unemployment, cohabitation, and high lethality were risk factors of suicidal attempts in the elderly. Similar results were observed in the study classified by suicide method. Conclusion: Chronic disease, depression, unemployment, and lethality were found to be risk factors of suicidal attempts in the elderly. However, unlike previous reports, several risk factors, including male sex, cohabitation, and suicide intention took on a different aspect in our study. The differences in these characteristics can be an important guide aiming to develop specific elderly suicide precautions. [ABSTRACT FROM AUTHOR]

We present a simple and up-scalable method to produce highly repaired graphene oxide with a large surface area, by introducing spherical multi-layered graphene balls with empty interiors. These graphene balls are prepared via chemical vapor deposition (CVD) of Ni particles on the surface of the graphene oxides (GO). Transmission electron microscopy and Raman spectroscopy results reveal that defects in the GO surfaces are well repaired during the CVD process, with the help of nickel nanoparticles attached to the functional groups of the GO surface, further resulting in a high electrical conductivity of 18,620 S/m. In addition, the graphene balls on the GO surface effectively prevent restacking of the GO layers, thus providing a large surface area of 527 m2/g. Two electrode supercapacitor cells using this highly conductive graphene material demonstrate ideal electrical double layer capacitive behavior, due to the effective use of the outstanding electric conductivity and the large surface area. [ABSTRACT FROM AUTHOR]