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Rh system

Xiaoqiang Huang, Shipeng Luo, Olaf Burghaus, Richard D Webster, Klaus Harms, Eric Meggers
We report an unusual reaction design in which a chiral bis-cyclometalated rhodium(iii) complex enables the stereocontrolled chemistry of photo-generated carbon-centered radicals and at the same time catalyzes an enantioselective sulfonyl radical addition to an alkene. Specifically, employing inexpensive and readily available Hantzsch esters as the photoredox mediator, Rh-coordinated prochiral radicals generated by a selective photoinduced single electron reduction are trapped by allyl sulfones in a highly stereocontrolled fashion, providing radical allylation products with up to 97% ee...
October 1, 2017: Chemical Science
Enamul Haque Mojumdar, Quoc Dat Pham, Daniel Topgaard, Emma Sparr
Hydration is a key aspect of the skin that influences its physical and mechanical properties. Here, we investigate the interplay between molecular and macroscopic properties of the outer skin layer - the stratum corneum (SC) and how this varies with hydration. It is shown that hydration leads to changes in the molecular arrangement of the peptides in the keratin filaments as well as dynamics of C-H bond reorientation of amino acids in the protruding terminals of keratin protein within the SC. The changes in molecular structure and dynamics occur at a threshold hydration corresponding to ca...
November 16, 2017: Scientific Reports
Christophe V Deraedt, Rong Ye, Walter Ralston, F Dean Toste, Gabor A Somorjai
Nanoparticles (Pd, Pt, Rh) stabilized by G4OH PAMAM dendrimers and supported in SBA-15 (MNPs/SBA-15 with M= Pd, Pt, Rh) were efficiently used as catalysts in the acceptorless dehydrogenation of tetrahydroquinoline/indoline derivatives in toluene (release of H2) at 130 °C. These catalysts are air stable, very active, robust, and recyclable during the process. The reverse hydrogenation reaction of quinoline derivatives (H2 storage) was also optimized and successfully performed in presence of the same catalysts in toluene at 60 °C under only 1 atmosphere of hydrogen gas...
November 16, 2017: Journal of the American Chemical Society
Dongsheng Rong, Shida Gong, Chaoyang Wang, Qiong Luo, Qian-Shu Li, Yaoming Xie, R Bruce King, Henry F Schaefer
The photochromic dithionite complex Cp*2Rh2(μ-CH2)2(μ-O2SSO2) (Cp* = η(5)-Me5C5) is of interest because it undergoes an unusual fully reversible unimolecular photochemical rearrangement to the isodithionite complex Cp*2Rh2(μ-CH2)2(μ-O2SOSO). In order to obtain more insight into these systems, a comprehensive density functional theory study has been carried out on isomeric Cp2M2(CH2)2(SO2)2 (M = Rh, Ir) derivatives. The experimentally observed rhodium complexes with coupled sulfur dioxide (SO2) units to give dithionite or isodithionite ligands are surprisingly high-energy kinetic isomers in our analysis, reflecting the need for dithionite rather than SO2 for their synthesis...
November 15, 2017: Inorganic Chemistry
Hansol D Lee, Kamal K Ray, Alexei V Tivanski
Currently, the impact of various phase states of aerosols on the climate is not well understood, especially for submicrometer sized aerosol particles that typically have extended life time in the atmosphere. This is largely due to the inherent size-limitations present in current experimental techniques that aim to directly assess the phase states of fine aerosol particles. Here-in we present a technique that uses atomic force microscopy (AFM) to directly probe for the phase states of individual, submicrometer particles by using nanoindentation and nano-Wilhelmy methodologies as a function of relative humidity (RH) and ambient temperature conditions...
November 14, 2017: Analytical Chemistry
Naoto Suzuki, Masatoshi Kawahata, Kentaro Yamaguchi, Toyofumi Suzuki, Kazuo Tomono, Toshiro Fukami
OBJECTIVE: The aim of this study is to evaluated evaluated the relative stability of pharmaceutical cocrystals consisting of paracetamol (APAP) and oxalic acid (OXA) or maleic acid (MLA). SIGNIFICANCE: These observations of cocrystal stability under various conditions are useful coformer criteria when cocrystals are selected as the API in drug development. METHOD: The relative stability was determined from the preferentially formed cocrystals under various conditions...
November 13, 2017: Drug Development and Industrial Pharmacy
John Ewart McGrady, Nicholas Perkins, Mohammed Obies, Graham Heath, Alison Edwards, Vaida Arcisauskaite
We report here the synthesis and physical properties of two new cationic tri-metallic chains, [(PEt3)3RuCl3M'Cl3Ru(PEt3)3]1+, M' = Rh and Ir. These are isostructural with a previously reported 17-electron all-ruthenium analogue, but the switch from an open-shell d5 Ru3+ ion to d6 Rh3+/Ir3+ in the central position has profound impact on the nature of the metal-metal bonding. X-ray crystallography and spectro-electrochemistry, complemented by electronic structure analysis at the DFT and CASSCF levels, indicate that whilst the presence of a Ru3+ ion in the center of the chain allows multi-center covalent bonding to develop, a closed-shell Rh3+/Ir3+ ion pushes the system towards the exchange-coupled limit, where the terminal Ru centers are only weakly interacting...
November 13, 2017: Chemistry: a European Journal
Tomoka Ozaki, Junki Matsuoka, Maho Tsubota, Shiori Tomita, Fumiko Sekiguchi, Takeshi Minami, Atsufumi Kawabata
Cav3.2 T-type Ca(2+) channel activity is suppressed by zinc that binds to the extracellular histidine-191 of Cav3.2, and enhanced by H2S that interacts with zinc. Cav3.2 in nociceptors is upregulated in an activity-dependent manner. The enhanced Cav3.2 activity by H2S formed by the upregulated cystathionine-γ-lyase (CSE) is involved in the cyclophosphamide (CPA)-induced cystitis-related bladder pain in mice. We thus asked if zinc deficiency affects the cystitis-related bladder pain in mice by altering Cav3...
November 9, 2017: Toxicology
Gerda Rentschler, Ilia Rodushkin, Milena Cerna, Chunying Chen, Florencia Harari, Raúl Harari, Milena Horvat, Frantiska Hruba, Lucie Kasparova, Kvetoslava Koppova, Andrea Krskova, Mladen Krsnik, Jawhar Laamech, Yu-Feng Li, Lina Löfmark, Thomas Lundh, Nils-Göran Lundström, Badiaa Lyoussi, Darja Mazej, Josko Osredkar, Krystyna Pawlas, Natalia Pawlas, Adam Prokopowicz, Staffan Skerfving, Janja Snoj Tratnik, Vera Spevackova, Zdravko Spiric, Anneli Sundkvist, Ulf Strömberg, Drazenka Vadla, Katerina Wranova, Soumia Zizi, Ingvar A Bergdahl
BACKGROUND: There is little reliable information on human exposure to the metals platinum (Pt), palladium (Pd) and rhodium (Rh), despite their use in enormous quantities in catalytic converters for automobile exhaust systems. OBJECTIVES: To evaluate blood concentrations of Pt (B-Pt), Pd (B-Pd) and Rh (B-Rh) in women from six European and three non-European countries, and to identify potentially influential factors. In addition, molybdenum (Mo) and strontium (Sr) were analysed...
November 2, 2017: International Journal of Hygiene and Environmental Health
Elizna M Schoeman, Eileen V Roulis, Yew-Wah Liew, Jacqueline R Martin, Tanya Powley, Brett Wilson, Glenda M Millard, Eunike C McGowan, Genghis H Lopez, Helen O'Brien, Jennifer A Condon, Robert L Flower, Catherine A Hyland
BACKGROUND: We previously demonstrated that targeted exome sequencing accurately defined blood group genotypes for reference panel samples characterized by serology and single-nucleotide polymorphism (SNP) genotyping. Here we investigate the application of this approach to resolve problematic serology and SNP-typing cases. STUDY DESIGN AND METHODS: The TruSight One sequencing panel and MiSeq platform was used for sequencing. CLC Genomics Workbench software was used for data analysis of the blood group genes implicated in the serology and SNP-typing problem...
November 8, 2017: Transfusion
Oleg Lupan, Fabian Schütt, Vasile Postica, Daria Smazna, Yogendra Kumar Mishra, Rainer Adelung
In this work, the influence of carbon nanotube (CNT) hybridization on ultraviolet (UV) and gas sensing properties of individual and networked ZnO nanowires (NWs) is investigated in detail. The CNT concentration was varied to achieve optimal conditions for the hybrid with improved sensing properties. In case of CNT decorated ZnO nanonetworks, the influence of relative humidity (RH) and applied bias voltage on the UV sensing properties was thoroughly studied. By rising the CNT content to about 2.0 wt% (with respect to the entire ZnO network) the UV sensing response is considerably increased from 150 to 7300 (about 50 times)...
November 7, 2017: Scientific Reports
Nilay Hazari, Jessica E Heimann
Carbon dioxide (CO2) is an appealing feedstock for the sustainable preparation of a variety of carbon-based commodity chemicals because of its high abundance, low cost, and nontoxicity. The high kinetic and thermodynamic stability of CO2, however, means that there are currently only a limited number of practical catalytic systems for the conversion of CO2 into more valuable chemicals, and continued research in this area is required. One promising approach for the eventual transformation of CO2 is to initially insert the molecule into transition-metal-element σ bonds such as M-H, M-OR, M-NR2, and M-CR3 bonds to form products of the type M-OC(O)E (E = H, OR, NR2, or CR3)...
November 8, 2017: Inorganic Chemistry
Huijun Chen, Yipshu Pui, Chengyu Liu, Zhen Chen, Ching-Chiang Su, Michael Hageman, Munir Hussain, Roy Haskell, Kevin Stefanski, Kimberly Foster, Olafur Gudmundsson, Feng Qian
Amorphous phase separation (APS) is commonly observed in amorphous solid dispersions (ASD) when exposed to moisture. The objective of this study was to investigate: 1) the phase behavior of amorphous solid dispersions composed of a poorly water-soluble drug with extremely low crystallization propensity, BMS-817399, and PVP, following exposure to different relative humidity (RH), and 2) the impact of phase separation on the intrinsic dissolution rate of amorphous solid dispersion. Drug-polymer interaction was confirmed in ASDs at different drug loading using Infrared (IR) spectroscopy and water vapor sorption analysis...
October 26, 2017: Journal of Pharmaceutical Sciences
Lihong Xiao, Abou Yobi, Karen L Koster, Yikun He, Melvin J Oliver
The moss Physcomitrella patens, a model system for basal land plants, tolerates several abiotic stresses, including dehydration. We previously reported that Physcomitrella patens survives equilibrium dehydration to -13 MPa in a closed system at 91% RH. Tolerance of desiccation to water potentials below -100 MPa was only achieved by pre-treatment with exogenous ABA. We report here that gametophores, but not protonemata, can survive desiccation below -100 MPa after a gradual drying regime in an open system, without exogenous ABA...
November 6, 2017: Plant, Cell & Environment
Cheng He, Ling Kong, Lijuan Zhou, Jing Xia, Haixia Wei, Min Liu, Hongjuan Peng
The obligate intracellular parasite, Toxoplasma gondii, manipulates the cytoskeleton of its host cells to facilitate infection. A significant rearrangement of host cell vimentin around Toxoplasma parasitophorous vacuoles is observed during the course of infection. ROP18 (TgROP18) is a serine-threonine kinase secreted by T. gondii rhoptry and a major virulence factor; however, the mechanisms by which this kinase modulates host factors remain poorly understood. Different and dynamic patterns of vimentin solubility, phosphorylation, and expression levels were observed in host cells infected with T...
2017: International Journal of Biological Sciences
Sivapragasam Chandrasekaran, Vanitha Sankararajan, Nampoothiri Neelakandhan, Mahalakshmi Ram Kumar
This study, through extensive experiments and mathematical modeling, reveals that other than retention time and wastewater temperature (Tw), atmospheric parameters also play important role in the effective functioning of aquatic macrophyte-based treatment system. Duckweed species Lemna minor is considered in this study. It is observed that the combined effect of atmospheric temperature (Tatm), wind speed (Uw), and relative humidity (RH) can be reflected through one parameter, namely the "apparent temperature" (Ta)...
November 4, 2017: Environmental Monitoring and Assessment
Joonhee Park, Siyeon Kim, Do-Hee Kim, Seongwon Cha, Joo-Young Lee
This study was conducted to investigate the effects of chronic and repetitive diving in cold sea water on physiological responses to cold in older Korean female divers, Haenyeo, who have been exposed to cold water through breath-hold diving since their teens. Young and older females, who have no experience of swimming in cold sea water, were recruited as control groups: older haenyeos (N = 10, 70 ± 3 years of age), young non-diving females (N = 10, 23 ± 2 years), and older non-diving females (N = 6, 73 ± 4 years)...
November 3, 2017: International Journal of Biometeorology
Arshad Bashir Khan, Ram Sharnagat Thakur
OBJECTIVE: To design and evaluate novel, feasible, safe, mucoadhesive intravaginal tablets of tenofovir disoproxil fumarate (TDF). SIGNIFICANCE: It may provide pre-exposure prophylaxis for women against HIV. METHODS: TDF intravaginal tablets were formulated employing poylvinylpyrrolidone (PVP) as the matrix forming polymer and various mucoadhesive polymers such as carbopol 934, 940, chitosan, and sodium carboxymethylcellulose (SCMC). Wet granulation was used...
October 30, 2017: Drug Development and Industrial Pharmacy
Joe M Viljoen, Danélia Botes, Jan H Steenekamp
Viral and fungal dermatological manifestations are often the first and only sign of HIV/AIDS. They are cosmetically disfiguring and threaten the quality of life, but can be treated by acyclovir and ketoconazole, correspondingly. This study attempted the formulation of stable, double fixed-dose acyclovir and ketoconazole novel transmucosal dosage forms, which are able to provide an efficient flux for both compounds. A cream, gel and lip balm formulation containing both drugs were formulated that can be applied to mucosal tissue...
November 1, 2017: European Journal of Pharmaceutical Sciences
Chunxue Zhou, Vanessa H Routh
We previously showed that the glutathione precursor, N-acetylcysteine (NAC), prevented hypoglycemia-associated autonomic failure (HAAF) and impaired activation of ventromedial hypothalamus (VMH) glucose-inhibited (GI) neurons by low glucose after recurrent hypoglycemia (RH) in non-diabetic rats. However, NAC does not normalize glucose sensing by VMH GI neurons when RH occurs during diabetes. We hypothesized that recruiting the thioredoxin (Trx) antioxidant defense system would prevent HAAF and normalize glucose sensing after RH in diabetes...
October 27, 2017: Diabetes
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