Half-sandwich Complexes of Ruthenium; Synthesis and Application to Catalysis

This thesis describes syntheses and catalytic reactivity of several half-sandwich complexes of ruthenium. The neutral ruthenium trihydride complex, Cp(PPri3)RuH3(1), can efficiently catalyse the H/D exchange reaction between various organic substrates and deuterium sources, such as benzene-d6. Moreover, the H/D exchange reactions of polar substrates were also observed in D2O, which is the most attractive deuterium source due to its low cost and low toxicity. Importantly, the H/D exchange under catalytic conditions was achieved not only in aromatic compounds but also in substituted liphatic compounds. Interestingly, in the case of alkanes and alkyl chains, highly selective deuterium incorporation in the terminal methyl positions was observed. It was discovered that the methylene units are engaged in exchange only if the molecule contains a donating functional group, such as O-and N-donors, C=C double bonds, arenes and CH3. The cationic half-sandwich ruthenium complex [Cp(PPri3)Ru(CH3CN)2]+(2) catalyses the chemoselective mono-addition of HSiMe2Ph to pyridine derivatives to selectively give the 1,4-regiospecific, N-silylated products. An ionic hydrosilylation mechanismis suggested based on the experiments. To support this mechanistic proposal, kinetic studies under catalytic conditions were performed. Also, the 1,4-regioselective mono-hydrosilylation of nitrogen containing compounds such as phenanthroline, quinoline and acridine can be achieved with the related Cp*complex [Cp*(phen)Ru(CH3CN)]+(3) (phen = 1,10-phenanthroline) and HSiMe2Ph under mild conditions. The cationic ruthenium complex 2 can also be used as an efficient catalyst for transfer hydrogenation of various organic substrates including carbonyls, imines, nitriles and esters. Secondary alcohols, amines, N-isopropylidene amines and ether compounds can be obtained in moderate to high yields. In addition, other ruthenium complexes, 1,3 and [Cp*(PPri3)Ru(CH3CN)2]+(4), can catalyse transfer hydrogenation of carbonyls although the reactions were sluggish compared to the ones of 2. The possible intermediate, Cp(PPri3)Ru(CH3CN)(H), was characterized by NMR at low temperature and the kinetic studies for the transfer hydrogenation of acetophenone were performed. Recently, chemoselective reduction of acid chlorides to aldehydes catalysed by the complex 2 was reported. To extend the catalytic reactivity of 2, reduction of iminoyl chlorides, which can be readily obtained from secondary amides, to the corresponding imines and aldehydes was investigated. Various substituted iminoyl chlorides were converted into the imines and aldehydes under mild conditions and several products were isolated with moderate yields

Beyond slurry-cast supercapacitor electrodes: PAN/MWNT heteromat-mediated ultrahigh capacitance electrode sheets

Supercapacitors (SCs) have garnered considerable attention as an appealing power source for forthcoming smart energy era. An ultimate challenge facing the SCs is the acquisition of higher energy density without impairing their other electrochemical properties. Herein, we demonstrate a new class of polyacrylonitrile (PAN)/multi-walled carbon tube (MWNT) heteromat-mediated ultrahigh capacitance electrode sheets as an unusual electrode architecture strategy to address the aforementioned issue. Vanadium pentoxide (V2O5) is chosen as a model electrode material to explore the feasibility of the suggested concept. The heteromat V2O5 electrode sheets are produced through one-pot fabrication based on concurrent electrospraying (for V2O5 precursor/MWNT) and electrospinning (for PAN nanofiber) followed by calcination, leading to compact packing of V2O5 materials in intimate contact with MWNTs and PAN nanofibers. As a consequence, the heteromat V2O5 electrode sheets offer three-dimensionally bicontinuous electron (arising from MWNT networks)/ion (from spatially reticulated interstitial voids to be filled with liquid electrolytes) conduction pathways, thereby facilitating redox reaction kinetics of V2O5 materials. In addition, elimination of heavy metallic foil current collectors, in combination with the dense packing of V2O5 materials, significantly increases (electrode sheet-based) specific capacitances far beyond those accessible with conventional slurry-cast electrodes.ope

Kinase-Based Taming of Brain Microglia Toward Disease-Modifying Therapy

Microglia are the primary immune cells residing in the central nervous system (CNS), where they play essential roles in the health and disease. Depending on the CNS inflammatory milieu, they exist in either resting or activated states. Chronic neuroinflammation mediated by activated microglia is now considered to be a common characteristic shared by many neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis, which currently pose a significant socioeconomic burden to the global healthcare system. Accumulating evidence has indicated protein kinases (PKs) as important drug targets for therapeutic interventions of these detrimental diseases. Here, we review recent findings suggesting that selected PKs potentially participate in microglia-mediated neuroinflammation. Taming microglial phenotypes by modulating the activity of these PKs holds great promise for the development of disease-modifying therapies for many neurodegenerative diseases

Impacts of gender, weather, and workplace differences in farm worker's gear

Background: The farmers cannot help working in outdoor conditions which have high humidity and solar radiation during the harvest period. Wearable items including clothing are the nearest environment of human body, and to understand the current state of them can be a way to set up an active prevention strategy against the health risk from heat stress in summertime agriculture. The aim of this study was to investigate the work wear and accessories which the elderly farmers used during agricultural working. Methods: One hundred twenty farmers (49 males and 71 females) working in nine separate sites on different days took part in this study. The average age of subjects was 61 years old. We examined the types of working posture, clothing, and items that the farmers used and/or wore. We also interviewed the farmers to know why they used such items while working. Results: The results of this study were as follows: (1) Farmers worked in the thermal environment which was over wet bulb globe temperature (WBGT) reference value, and the farmers could suffer heat stress due to workload induced from wearing conventional long-sleeved shirts and long trousers which were 0.66 clo in average under this summertime working thermal condition. (2) The farmers tended to change the layer of upper clothing for adapting to weather condition. (3) The types of footwear used seemed to be related with facilities as well as weather, and farmers tended to wear lighter footwear when the weather is hotter or when they work in PVC greenhouse. The majority of elderly farmers wore loafers and rubber shoes which had indistinguishable thin soles. (4) The types of hats showed the difference between facilities as well as gender and only 31.7 % of all participants used long brims. (5) Korean elderly farmers did not use any active cooling item as agricultural auxiliary tools in summer harvesting time. Conclusions: Korean elderly farmers worked in poor surroundings which could threaten their health and safety and seemed not to adjust their workload and clothing during summer harvest season. Thus, it would be necessary to monitor individual responses in order to ensure that the risk of heat stress is preventedopen

(E)-4-{[(Pyridin-4-yl­methyl­idene)amino]­meth­yl}benzoic acid

The title mol­ecule, C14H12N2O2, exhibits a V-shaped conformation with a dihedral angle of 59.69 (3)° between the benzene and pyridine rings. In the crystal, O—H⋯N hydrogen bonds link the mol­ecules into zigzag chains along [010]

Optic neuritis caused by aspergilloma within Onodi cell pyomucocele in a 62-year-old woman

Onodi cells are anatomical variants of the posterior ethmoidal cells, which are greatly pneumatized laterally, and to some degree superiorly, to the sphenoid sinuses. Th e clinical importance of the Onodi cell is that it contains the optic canal and lies in close proximity to the optic nerve. Although the incidence of Onodi cell pathologies such as mucocele is extremely low, they may cause ophthalmological complications due to the close anatomical proximity between the Onodi cell and the optic nerve. Optic neuritis caused by aspergillosis of the Onodi cell, presenting in the Emergency Department as an aspergilloma within a pyomucocele, has not been reported previously. Here, we describe the fi rst such case; the aspergilloma within the pyomucocele was completely removed via surgical endoscopy

The Role of Echocardiography in Evaluating Cardiovascular Diseases in Patients with Diabetes Mellitus

Patients with diabetes mellitus are highly susceptible to cardiovascular complications, which are directly correlated with cardiovascular morbidity and mortality. In addition to coronary artery disease, there is growing awareness of the risk and prevalence of heart failure (HF) in patients with diabetes. Echocardiography is an essential diagnostic modality commonly performed in patients with symptoms suggestive of cardiovascular diseases (CVD), such as dyspnea or chest pain, to establish or rule out the cause of symptoms. Conventional echocardiographic parameters, such as left ventricular ejection fraction, are helpful not only for diagnosing CVD but also for determining severity, treatment strategy, prognosis, and response to treatment. Echocardiographic myocardial strain, a novel echocardiographic technique, enables the detection of early changes in ventricular dysfunction before HF symptoms develop. This article aims to review the role of echocardiography in evaluating CVD in patients with diabetes mellitus and how to use it in patients with suspected cardiac diseases

Turbo Warrants under Hybrid Stochastic and Local Volatility

This paper considers the pricing of turbo warrants under a hybrid stochastic and local volatility model. The model consists of the constant elasticity of variance model incorporated by a fast fluctuating Ornstein-Uhlenbeck process for stochastic volatility. The sensitive structure of the turbo warrant price is revealed by asymptotic analysis and numerical computation based on the observation that the elasticity of variance controls leverage effects and plays an important role in characterizing various phases of volatile markets