Search

Geometric isomers of mononuclear ruthenium(II) complexes

Pt nanoparticles stabilized by a polymeric stabilizer of polyacrylic acid were stably adsorbed on an ITO electrode to work effectively and stably for electrocatalytic proton reduction.

A Pt cathode (Pt(w-MeIm)) prepared by a mixed metal-imidazole casting (MiMIC) method showed a remarkably superior hydrogen evolution reaction (HER) performance compared to the cathode prepared without imidazole (Pt(w/o-MeIm)), and the common Pt-based benchmark cathodes of Pt/C or the Pt plate.

A high performance for PEC water oxidation results from the formation of a p–n junction at the interface between CoPi and α-Fe2O3, which is first observed among the hitherto-reported α-Fe2O3/CoPi-based electrodes.

Staphylococcus aureus is a Gram-positive bacterium that plays a role in the pathogenesis of skin lesions in diabetes mellitus, atopic dermatitis, and psoriasis, all of which are associated with elevated non-enzymatic glycation biomarkers. The production of biofilm protects resident bacteria from host immune defenses and antibiotic interventions, prolonging pathogen survival, and risking recurrence after treatment. Glycated proteins formed from keratin and glucose induce biofilm formation in S. aureus, promoting dysbiosis and increasing pathogenicity. In this study, several glycation-inhibiting and advanced glycation endproduct (AGE) crosslink-breaking compounds were assayed for their ability to inhibit glycated keratin-induced biofilm formation as preliminary screening for clinical testing candidates. Ascorbic acid, astaxanthin, clove extract, n-phenacylthiazolium bromide, and rosemary extract were examined in an in vitro static biofilm model with S. aureus strain ATCC 12600. Near complete biofilm inhibition was achieved with astaxanthin (ED50 = 0.060 mg/mL), clove extract (ED50 = 0.0087 mg/mL), n-phenacylthiazolium bromide (ED50 = 5.3 mg/mL), and rosemary extract (ED50 = 1.5 mg/mL). The dosage necessary for biofilm inhibition was not significantly correlated with growth inhibition (R2 = 0.055. p = 0.49). Anti-glycation and AGE breaking compounds with biofilm inhibitory activity are ideal candidates for treatment of S. aureus dysbiosis and skin infection that is associated with elevated skin glycation.

Facile and scalable fabrication of α-Fe2O3 photoanodes using a precursor solution containing FeIII ions and 1-ethylimidazole (EIm) in methanol was demonstrated to afford a rigidly adhered α-Fe2O3 film with a controllable thickness on a fluorine-doped tin oxide (FTO) substrate. EIm ligation to FeIII ions in the precursor solution brought about high crystallinity of three-dimensionally well-interconnected nanoparticles of α-Fe2O3 upon sintering. This is responsible for the 13.6 times higher photocurrent density (at 1.23 V vs reference hydrogen electrode (RHE)) for photoelectrochemical (PEC) water oxidation on the α-Fe2O3 (w-α-Fe2O3) photoanode prepared with EIm compared with that (w/o-α-Fe2O3) prepared without EIm. The w-α-Fe2O3 photoanode provided the highest charge separation efficiency (ηsep) value of 27% among the state-of-the-art pristine α-Fe2O3 photoanodes, providing incident photon-to-current conversion efficiency (IPCE) of 13% at 420 nm and 1.23 V vs RHE. The superior ηsep for the w-α-Fe2O3 photoanode is attributed to the decreased recombination of the photogenerated charge carriers at the grain boundary between nanoparticles, in addition to the higher number of the catalytically active sites and the efficient bulk charge transport in the film, compared with w/o-α-Fe2O3.

BACKGROUND Inflammatory lipid mediators in mesenteric lymph (ML), including arachidonic acid (AA), are considered to play an important role in the pathogenesis of multiple-organ dysfunction after hemorrhagic shock. A previous study suggested that vagus nerve stimulation (VNS) could relieve shock-induced gut injury and abrogate ML toxicity, resulting in the prevention of multiple-organ dysfunction. However, the detailed mechanism of VNS in lymph toxicity remains unclear. The study aimed to investigate the relationship between VNS and inflammatory lipid mediators in ML. METHODS Male Sprague-Dawley rats underwent laparotomy and superior mesenteric artery obstruction (SMAO) for 60 minutes to induce intestinal ischemia followed by reperfusion and observation. The ML duct was cannulated, and ML samples were obtained both before and after SMAO. The distal ileum was removed at the end of the observation period. In one group of animals, VNS was performed from 10 minutes before 10 minutes after SMAO (5 V, 0.5 Hz). Liquid chromatography-electrospray ionization-tandem mass spectrometry analysis of AA was performed for each ML sample. The biological activity of ML was examined using a monocyte nuclear factor κ-light-chain-enhancer of activated B cells activation assay. Western blotting of phospholipase A2 group IIA (PLA2-IIA) was also performed for ML and ileum samples. RESULTS Vagus nerve stimulation relieved the SMAO-induced histological gut injury. The concentration of AA and level of nuclear factor κ-light-chain-enhancer of activated B cells activation in ML increased significantly after SMAO, whereas VNS prevented these responses. Western blotting showed PLA2-IIA expression in the ML and ileum after SMAO; however, the appearance of PLA2-IIA band was remarkably decreased in the samples from VNS-treated animals. CONCLUSION The results suggested that VNS could relieve gut injury induced by SMAO and decrease the production of AA in ML by altering PLA2-IIA expression in the gut and ML.

Artificial photosynthesis technologies require transparent thin film catalysts working efficiently for water oxidation in neutral pH media for penetration of light to the inner light-harvesting lay...

A rigidly adhered nitrogen-doped BiVO4 photoanode with a narrow band gap energy (Eg = 2.35 eV) for water oxidation was developed to attain the IPCE value of 35.1% at 440 nm which is among the highe...

The critical bottleneck for water splitting, which is important for sustainable production of hydrogen, has remained in sluggish oxygen evolving reaction (OER) requiring insufficiently low overpote...

Electrocatalytic splitting of water to oxygen and hydrogen is one of the most promising approaches for sustainable production of hydrogen as a carbon-neutral fuel. To establish efficient electrocatalytic water splitting, the overall overpotential for this reaction must be minimized via developing efficient catalysts to promote oxygen and hydrogen evolution at the anode and the cathode, respectively. However, the overpotentials for oxygen evolution are insufficiently low (162–300 mV for a current density of 10 mA cm−2), and the value less than 100 mV still remains untracked. Here, we report the unprecedentedly low of 32 mV for oxygen evolution attained by the formation of a unique motif of nickel sulfide nanowires stuffed into carbon nitride scabbards (NiSx/C3N4), demonstrating electrocatalytic water splitting at the lowest overall overpotential of 72 mV using the NiSx/C3N4 anode. This motif provides a key to guided thought for the development of efficient catalysts for oxygen evolution.

To evaluate the moisturizing function and other effects of royal jelly extract on the skin. The effects of applying an essence containing royal jelly extract on the skin of healthy Japanese males and females were examined.Thirty-five healthy Japanese men and women who were aware of their skin dryness applied an essence containing royal jelly extract or placebo for 4 weeks using the split-face method in a placebo-controlled, double-blind, parallel comparative study. The stratum corneum water content, transepidermal water evaporation, pigmentation, pores, and redness were evaluated.The stratum corneum water content significantly increased by the application of essence containing royal jelly extract to the cheeks for 4 weeks compared with placebo.The application of an essence containing royal jelly extract significantly improved the moisture content of the stratum corneum of the cheeks, confirming the improvement in the moisturizing function of the royal jelly extract. Furthermore, no adverse events were observed at the application site during the application period, and the test products and royal jelly extract contained in the test product were considered highly safe.

Dinuclear ruthenium(II) complexes, proximal,proximal-[Ru2(Hcptpy)2L(μ-Cl)]3+ (Ru2(μ-Cl), Hcptpy = 4′-(4-carboxyphenyl)-2,2′;6′,2″-terpyridine and L = 5-phenyl-2,8-di(2-pyridyl)-1,9,10-anthyridine) ...

Oxygen-evolution-reaction (OER) and oxygen-reduction-reaction (ORR) catalysts on a gas-diffusion carbon paper (CP) electrode have been explored as a current hot topic. Low-cost and earth-abundant F...

Background Intestinal ischemia caused by hemorrhagic shock is known to induce systemic inflammatory responses. Previous studies have shown that mesenteric lymph (ML) plays a crucial role in gut-mediated inflammation. Lipid mediators, such as lysophosphatidylcholines (LPCs) which contain polyunsaturated fatty acids (PUFAs), are present in the post-shock ML. Exosomes are also present in the ML and act as transcellular carriers of lipids; however, their role in post-shock systemic inflammation has not been revealed. Here, we aimed to identify changes in lipid mediators in ML exosomes after intestinal ischemia. Methods Male Sprague-Dawley rats underwent laparotomy, followed by ML duct cannulation. Animals were subjected to 60 min of intestinal ischemia by superior mesenteric artery clamping, followed by 120 min of reperfusion. ML was obtained before and after intestinal ischemia and exosomes were isolated from ML by ultracentrifugation. The biological activity of ML exosomes was determined using the monocyte NF-κB activation assay. Lipids of ML exosomes were extracted and quantified by liquid chromatography/electrospray ionization mass spectrometry. Results ML exosomes-induced NF-κB activation significantly increased after intestinal ischemia and lipid analysis revealed a significant increase in the concentration of PUFA-containing LPCs. Additionally, PUFA-containing LPCs also induced NF-κB activation. Conclusion Our results suggest that biologically active lipid mediators in ML exosomes may be involved in the inflammatory response after intestinal ischemia. Level of evidence Not applicable (Basic Science paper).

A non-heme Fe complex with a tetradentate dicarboxamide N4 in-plane ligand works efficiently and selectively for the electrocatalytic CO2-to-CO conversion in a homogeneous DMF solution. The complex...

A new mononuclear Ru aquo complex [Ru(C8Otpy)(H2dcbpy)(OH2)]2+ with 4,4'-dicarboxy-2,2'-bipyridine (H2dcbpy) and 4'-octyloxy-2,2':6',2''-terpyridine (C8Otpy) ligands was synthesized to investigate electrocatalytic water oxidation by the complex immobilized on a mesoporous indium-doped tin oxide (meso-ITO) electrode using a multi-potential-step chronocoulospectrometric (MPSCCS) technique. UV-visible absorption spectroscopic data indicated that [Ru(C8Otpy)(dcbpy)(OH2)] (RuOH2) is deprotonated to [Ru(C8Otpy)(dcbpy)(OH)]- (RuOH) on the meso-ITO surface even at pH 5.9 of the electrolyte solution. The cyclic voltammogram (CV) of the RuOH/meso-ITO electrode showed a pH-independent redox response at E1/2 = 0.80 V vs. Ag/AgCl in the pH range of 5-12, being assigned to a non-proton-coupled 1e- redox process of RuIIOH/RuIIIOH. The MPSCCS measurement of the RuOH/meso-ITO electrode between 0.2 and 1.5 V vs. Ag/AgCl showed that RuIV species (tentatively RuIVO) exist in a steady state of the electrocatalysis in the initial stage. This suggests that the electrochemical oxidation from RuIVO to RuVO could compete with the water nucleophilic attack for O-O bond formation involved in the rate-determining step under the employed conditions. The possibility that the water nucleophilic attack on RuIVO could also compete with the electrochemical oxidation of RuIVO to RuVO was suggested by the electrocatalytic water oxidation at a low applied potential of 1.4 V prior to the formation potential of RuVO. The MPSCCS measurement at 1.4 V for 1 h showed that RuOH is gradually transformed into an alternative catalyst (most likely RuOx nanoparticles) on the electrode. The MPSCCS technique is promising to reveal the redox reactions and catalytic aspects of molecular catalysts immobilized on an electrode for water oxidation.

A ruthenium complex showing multi-stimuli-responsive isomerization was synthesized. The catalytic activity of this complex toward water oxidation showed responses to visible-light irradiation and heat due to photoisomerization and thermal back-isomerization, respectively. DFT calculations suggested that a pendant moiety in the complex was key to controlling the catalytic activity.

Glycative stress is a conception of a state that causes an excess of carbohydrate-derived or fatty acid-derived short-chain aldehydes in the body. Short-chain aldehydes, which are highly reactive, undergo a carbonylation process with lysine and arginine residues in proteins and form advanced glycation endproducts (AGEs). When postprandial hyperglycemia occurs, open-ring glucose with exposed aldehyde groups (-CHO) increases and various carbohydrate-derived aldehydes are formed simultaneously (this phenomenon is named “aldehyde sparks”). Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is an enzyme abundant intracellularly as the keystone of defense against glycative stress and plays a role in metabolizing highly toxic glyceraldehyde, however, under diabetic conditions, the enzyme activity is markedly reduced by forming S-(2-succinyl) cysteine-GAPDH. We also found that a high-fat diet reduced GAPDH activity and increased glyceraldehyde and methylglyoxal. High animal fat diets in particular require caution because they increase preference dependence on animal fat. In the lipid-rich brain, they promotes the formation of lipid-derived AGEs formed by methylglyoxal and acrolein providing evidence of their close association with amyloid cascade, ultimately leading to the onset of Alzheimer-type dementia. Through the process of amylod beta (Aβ) glycation modification and cross-linking, Aβ polymerization is promoted and deposited in the brain. Thus, neurotoxicity is aggravated. Furthermore, Aβ progresses toward being persistent and Aβ clearance is reduced. Tau proteins similarly undergo glycation modification and trigger polymerization. methylglyoxal or acrolein-derived glycated Aβ clearance by primary microglia cultured cells reduced significantly compared to the unglycated Aβ provides evidence of the reduced clearance upon glycation. It was also shown that melatonin, which promotes glycolytic cross-linking degradation, may promote microglial Aβ phagocytosis. We next plan to examine the potential of plant extracts that promote glycation cross-linking degradation to improve Aβ phagocytosis. Advanced Alzheimer-type dementia with a disoriented neural network hardly recovers with treatment. In this review article, we discussed possible future therapeutic strategies for Alzheimer-type dementia by increasing Aβ clearance from the early stage such as the prevention of Aβ-glycation and the promotion of glycated-Aβ degradation, which may be a paradigm shift.

Significance The understanding of O–O bond formation is of great importance for revealing the mechanism of water oxidation in photosynthesis and for developing efficient catalysts for water oxidation in artificial photosynthesis. The O–O bond formation was first observed from low-valent Ru III OH centers, although the high-valent Ru IV or V has been believed to be required for this process so far. The O–O bond formation was demonstrated to be induced by deprotonation of one of the OH ligands of Ru III 2 (OH) 2 centers via intramolecular coupling of the OH and deprotonated O − ligands, conjugated with two-electron transfer from two Ru III centers to their ligands to generated Ru II 2 (μ-OOH).

The understanding of O–O bond formation is of great importance for revealing the mechanism of water oxidation in photosynthesis and for developing efficient catalysts for water oxidation in artificial photosynthesis. The chemical oxidation of the Ru(II)(2)(OH)(OH(2)) core with the vicinal OH and OH(2) ligands was spectroscopically and theoretically investigated to provide a mechanistic insight into the O–O bond formation in the core. We demonstrate O–O bond formation at the low-valent Ru(III)(2)(OH) core with the vicinal OH ligands to form the Ru(II)(2)(μ-OOH) core with a μ-OOH bridge. The O–O bond formation is induced by deprotonation of one of the OH ligands of Ru(III)(2)(OH)(2) via intramolecular coupling of the OH and deprotonated O(−) ligands, conjugated with two-electron transfer from two Ru(III) centers to their ligands. The intersystem crossing between singlet and triple states of Ru(II)(2)(μ-OOH) is easily switched by exchange of H(+) between the μ-OOH bridge and the auxiliary backbone ligand.

Polypyridyl ruthenium(II) complexes have been widely researched as promising functional molecules. We have found unique photoisomerization reactions of polypyridyl ruthenium(II) aquo complexes. Recently we have attempted to provide insight into the mechanism of the photoisomerization of the complexes and distinguish between the distal−/proximal-isomers in their physicochemical properties and functions. Moreover, polypyridyl ruthenium(II) aquo complexes have been intensively studied as active water oxidation catalysts (WOCs) which are indispensable for artificial photosynthesis. The catalytic aspect and mechanism of water oxidation by the distal-/proximal-isomers of polypyridyl ruthenium(II) aquo complexes have been investigated to provide the guided thought to develop more efficient molecular catalysts for water oxidation. The recent progress on the photoisomerization and water oxidation of polypyridyl ruthenium(II) aquo complexes in our group are reviewed to understand the properties and functions of ruthenium complexes.

Intestinal ischemia-reperfusion injury leads to multiple organ injuries via gut-derived mediators following severe injury. Growing evidence suggests that exosomes secreted from intestinal epithelial cells are heavily involved in the development of systemic inflammation, but a full elucidation of its pathology remains to be completed. To produce an integrated understanding of its pathology, this study aimed to reveal the changes in exosome content after ischemic stimulation. Our result showed (1) the proteins involved in inflammation by catalyzing RNAs were upregulated, (2) hsa-miR-21-5p, hsa-miR-23a-3p, and hsa-miR-30d-5p levels were increased while hsa-miR-124-3p level was decreased, (3) the increase in unsaturated lysophosphatidylcholines levels. These results together with those of previous studies, suggest that lysophosphatidylcholines may activate the NK-κB pathway. The proteins and microRNAs jointly act to disrupt negative feedback, thereby increasing inflammation. Thus, our results clarify part of the mechanism of multi-organ failure after intestinal ischemic recanalization, thereby providing a new target for treatment.

We report our experience with needlescopic splenectomy (NS) for the surgical treatment of idiopathic thrombocytopenic purpura using a 3-mm needlescope with three ports. One patient was male and two were females, and their mean age was 58 years. The patient was placed in the right lateral decubitus position. The first 12-mm port was introduced through the lateral margin of the left rectus abdominis muscle, and the other two 3-mm ports were inserted in the left upper quadrant. NS was performed by a standard technique under the observation of 3.3-mm needlescope. The surgical procedure was successfully completed in all the patients. The mean duration of surgery, intra-operative bleeding volume and post-operative hospital stay were 176 min, 70 ml and 4.7 days, respectively. There were no particular peri-operative complications in spite of dense adhesions or simultaneous laparoscopic procedures. Our method is safe and feasible with low morbidity and without impairing cosmetic benefits.

Nanorod architecture of a N2-intercalated WO3 photoanode has been developed by emphasizing the dual role of N2H4, which functioned simultaneously as a structure-directing agent and as a nitrogen so...

The development of efficient catalyst materials for water oxidation is bottleneck to construct artificial photosynthesis that is a promising future energy-providing system. We review the recent progress on development of IrOx electrocatalyst films for water oxidation based on our latest research works. A controlled fabrication approach of an efficient IrOx electrocatalyst films is introduced by a facile spin-coating of a homogenous solution of Ir precursor complexes followed by simple annealing at different temperature. The composition and crystallinity of the IrOx film are tunable by a simple annealing treatment. The electrocatalytic properties of the IrOx film dramatically depended on annealing temperature are characterized to give the noticeably high performance at 300 °C annealing. A soft-template-assisted technique using different polymer surfactants as structure directing agents (SDAs) is illustrated in the spin-coating procedure to reveal impacts of SDAs on nanostructures and electrocatalytic water oxidation performances of the IrOx films. The characterization of the first accessible channel-like open pore architecture of the ordered 2D-hexagonal mesoporous IrOx film is described by a facile one-pot strategy using Pluronic F127 as SDA. The novel controlled nanostructures including mesoporous architecture of IrOx improves electrocatalytic performance for water oxidation relative to a conventional nanoparticulate structure of IrOx coating.

Post-fermented tea (dark tea) is produced from enzyme-inactivated fresh tea leaves by microbial fermentation. Batabata tea and Awaban tea are two major dark teas fermented under aerobic and anaerobic conditions, respectively. However, how their chemical compositions and functionalities change during different post-fermentation processes remains unclear. Nuclear magnetic resonance (NMR)-based analyses showed that (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC) and (-)-epicatechin (EC) decreased in Batabata tea during post-fermentation with aerobic molds. In contrast, EGC and EC increased, and pyrogallol was produced in Awaban tea during post-fermentation with lactic acid bacteria (LAB). The anti-glycation activities of two dark teas were investigated using an in vitro assay system with human serum albumin (HSA). The anti-glycation activity decreased in Batabata tea, but it was retained in Awaban tea during post-fermentation. Our results showed that post-fermentation with LAB was an efficient way to enhance phenol content and that pyrogallol contributed to anti-glycation activity of Awaban tea.