Search

The reactions of RuCl(PPh3)2Cp ([Ru]Cl, Cp = cyclopentadienyl) with aryl enynes 1a–1c containing propargyl alcohol and diallylamine groups on the aryl ring give the carbene complexes 2a–2c, each of which contains an indole group. With an additional methylene group, the aryl enyne 1d reacts with [Ru]Cl to afford the dihydroisoquinoline complex 3d. For 1a–1d, the C–N bond-forming process occurs when the triple bond is π-coordinated to the metal center. The reaction of [Ru]Cl with the aryl enyne 1e containing an isoxazole group affords the carbene complex 2e by a C–C bond formation between the isoxazole group and C-β of the triple bond, accompanied by the opening of the isoxazole ring. The reactions of 2a–2c and 2e with O2/NEt3 are assisted by visible light to afford the corresponding aldehydes 4a–4c and 5e. From DFT calculations, visible light results in the partial population of the lowest unoccupied molecular orbital (LUMO), which has Ru=C antibonding character; therefore, the bond is weakened, and the oxygenation/demetallation reactions are slightly promoted.

This paper reports on the experiments undertaken to determine the luminance of control panel assembly (CPA) and push button annunciate (PBA) in cockpits when operated in low and high ambient environment. Referring to the varying ways of commercial airplanes are illuminated, different levels of luminance are chosen to be tested. Psychology scales that measure comfort and legibility when under illumination are used as the two main evaluation indexes, which reflecting the performance of CPA and PBAs with different luminance levels according to the observers’ evaluation scores. 21 observers participated in the study, in which they were asked to give certain assessment. The results suggest that for both fully dark environment and the environment that only has light from the working displays, 0.4fl is the preferable luminance for CPA. For PBAs of different colors, the preferable luminance range is also different.

Dicopper(I) complexes {Cu2(bpnp)(CH3CN)4}(PF6)2] (2), [{Cu2(bpnp)(CH3CN)4}(BAr4F)2] (3) and [Cu2(bpnp)Cl2] (4) were prepared from the complexation of [Cu(CH3CN)4](PF6) with 2,7-bis(2-pyridyl)-1,8-naphthyridine (bpnp) followed by anion metathesis and treatment of chloride sequentially. The X-ray structural analysis of 4 indicates the molecule to have a twofold axis passing through the Cu2Cl2 core, which has the shape of a butterfly, and that the Cu atom is tetrahedrally coordinated with in a Cl2N2 donor set. In preliminary experiments 2 was found to be an effective catalyst in the coupling/cyclization of 2-bromobenzoic acids with amidines, providing the corresponding quinazolinones in good yields. Copyright © 2014 John Wiley & Sons, Ltd.

The coupling reaction of N-propargyl semi-salen compound 1d on [Ru]-Cl ([Ru] = Cp(PPh3)2Ru) generates the carbene complex 3d containing a substituted 2H-chromene unit in 7 d. The precursor vinylidene complex 2d is isolated from the reaction of the propargyl group of 1d with [Ru]-Cl in 12 h. Addition of an o-cresol moiety to Cα and Cβ of the vinylidene ligand of 2d takes place in a longer reaction time to yield 3d. Reactions of [Ru]-Cl with other analogous compounds 1a, 1b, and 1c, in excess, also afford carbene complexes 3a, 3b, and 3c, respectively, in 48 h via a similar coupling process. Their precursor vinylidene complexes 2a, 2b, and 2c are also observed in 12 h. Structures of 2 and 3 are determined on the basis of spectroscopic data. The solid state structure of the dppe analogue 3a′ is further confirmed by X-ray diffraction analysis. The added o-cresol part comes from compounds 1, instead of aldehyde which is confirmed by the cross-coupling reactions of 2 and 1 using mass spectrometry. For compariso...

e14199 Background: Prior study stratified Taiwanese oral cancer specimens (n = 40) and cell lines (n = 7) into three distinct molecular subtypes, namely classical (CL), mesenchymal (MS), and basal (BA). In a cell line derived xenograft (CDX) model, we observed MS grew at least 10-fold slower than CL did in immunodeficient mice. By using RNA-seq to portrait the transcriptomes of human tumor and mouse stroma simultaneously, contribution of mouse innate immunity in restricting the growth of human oral cancer cells was assessed. Methods: A half millions of mycoplasma-free OC3 (MS) or TW2.6 (CL) cells with matrigel were subcutaneously implanted into the flank of 10 to 16 weeks old NOG (NOD/SCID/Il2rgtm). RNAs of CDX tissues from OC3-NOG (n = 7) and TW2.6-NOG (n = 5) were extracted and subjected to stranded mRNA sequencing. Clean reads were aligned to GRCh38 (human) and GRCm38 (mouse), respectively, followed by identifying differentially expressed genes and gene set enrichment analysis. Results: Up-regulation of signature genes for dendritic cells and macrophages and enrichment of innate immunity, including Tnfa-Nfkb signaling, interferon alpha response, interferon gamma response and inflammation were detected in OC3- but not in TW2.6-CDXs. These results suggested that OC3 (MS) was more immunogenic than TW2.6 (CL), which is reminiscent of the inflammatory MS (IMS) subtype of head and neck cancer recently described by Keck et al (n = 938, Clin Cancer Res 2015, 21: p870. PMID: 25492084). Conclusions: By RNA-seq/xenome analysis of CDXs, we provide evidence that compared to CL, MS subtype of oral cancer cells elicited a stronger innate immunity in NOG mouse. Alternatively, CL subtype might have evolved as a prototype with superiority in immune escape.

It is significant to explore the fatigue contact damage of bi-layer ceramic composites in order to improve the long-time mechanical reliability of bi-layer structured dental restorations. In this study, Hertz contact test was used to compare the fracture modes and the ability of anti-fatigue damage of zirconia and alumina bi-layer composites, to analyze the effect of loading rate and other factors on the damage mechanisms of bi-layer ceramic composites. Cyclic spherical fatigue loading was put on the bi-layer alumina and zirconia composites with different substrates. The samples were observed by high depth of field stereomicroscope and digital optical microscope after test. The results showed that the fatigue contact damage mode of zirconia bi-layer composite was the porcelain fracture from radial cracks without the damage of zirconia core. The fatigue contact damage mode of alumina bi-layer composite was the alumina core failure from radial cracks as the function of contact load. For both of zirconia and alumina bi-layer samples, the number of cycles to the sample failure as the function of same maximum contact load with high loading rate was obviously smaller than low loading rate. The mechanical properties of the substrate materials had limited effects on the number of cycles to the failure of both zirconia and alumina bi-layer samples from contact-induced radial cracks as maximum contact load with low loading rate. The ability of the zirconia bi-layer composites to resist fatigue damage was much higher than that of the alumina bi-layer composites.

To assess the activity and safety of postoperative adjuvant immunotherapy with transfusion of cytokine-induced killer (CIK) cells combined with chemotherapy in patients with colorectal cancer.We retrospectively studied 96 consecutive patients with colorectal cancer who were treated with resection between January 2010 and December 2012 as well as adjuvant chemotherapy. Twenty-one of these patients accepted at least 1 cycle of CIK cell transfusion for immunotherapy (CIK group). Disease free survival (DFS), immune cells and treatment related side effects were assessed. The patients were followed up until May 2013.By the end of follow-up, 10 patients (10.42 %) had died. Eighteen patients (18.75 %) had withdrawn. All the patients in the CIK group are still alive, and only 1 patient had withdrawn. Patients in the CIK group had significantly longer DFS than those in the control group [HR = 0.28, 95 % CI (0.09, 0.91), p = 0.034]. The 2-year DFS rates of patients in the CIK group and the control group were 59.65 ± 24.80 % and 29.35 ± 6.39 %, respectively. The CD4(+)/CD8(+) ratios were significantly lower during the period of chemotherapy than those before chemotherapy (p = 0.0038), while the ratios were significantly higher during the period of CIK cell transfusion than those before CIK therapy (p = 0.0484). There were no immediate adverse reactions to the CIK cell transfusions.Adjuvant transfusion of CIK cells prolongs DFS in patients with colorectal cancer.

Complexation of 2,7-bis(2-pyridyl)-1,8-naphthyridine (bpnp) with Cu2O in formic acid under aerobic conditions provided a dicopper complex [Cu2(bpnp)(μ-OH)(HCOO)3] (1). This complex has been characterized by X-ray crystallographic and spectroscopic analysis. With O2 as the oxidant, complex 1 is an efficient catalyst for the oxidative coupling of alcohols with amines or diamines, leading to the corresponding imines or diimines in good to excellent yields.

Cyclization of terminal arylalkynes containing aldehyde (1a), ketone (1b-c) or hydroxyl (6a-c) functionality on the aryl ring induced by ruthenium complex is investigated. For the reaction of Cp(PPh3)2RuCl with o-ethynyl benzaldehyde 1a, a vinylidene intermediate was formed which is followed by a carbonyl attack to give 2a. However, for 1b-c, with a ketone replacing the aldehyde group, isobenzofuryl carbene complexes (4b-c) were formed as the major products along with the isochromene carbene complexes (2b-c) as the minor products. For three o-enynyl phenol compounds 6a-c with different substituents on the aryl ring, the reactions take place at the triple bond first giving vinylidene intermediates which undergo facile intramolecular cyclization to yield the cyclic oxocarbene complexes 7a-c in excellent yields. Modification of various substituents at Cβ of the carbene ligand of 7 by the use of different alkyl halides can be readily achieved under mild condition. For the chromane ring derivatives 11, the two allyl groups underwent ring closing metathesis reaction in the presence of Grubb's catalyst and yielded the tricyclic product 12. These chemical reactions and their mechanisms are corroborated by structure determinations of two ruthenium complexes using single crystal X-ray diffraction analysis.

The conventional method of producing porcelain standard disc specimens is based on the dental lab method for bilayer ceramic crowns, in order to reflect the clinical using condition. However heavy task is facing to the researchers, which is producing a large amount of the specimens efficiently. The press molding method is used to produce dental porcelain disc specimens in this study. Then, the basic mechanical properties of two groups of porcelain specimens were tested respectively, comparing with handmade and press molding method. The density was measured by Archimedes' method, the flexural strength was tested by biaxial bending test, and the hardness was checked by microhardness tester. The micro features of the specimens before and after bending test were observed under optical microscope and SEM. The results showed that there was no significant difference in the flexural strength, microhardness and density of porcelain discs made by two methods. Air pores were found in all specimens with size between 5-50 micrometers. The size and distribution of pores in the specimens by press molding method are more homogeneous than handmade method. Producing dental porcelain discs for laboratory testing specimens by press molding method was much easy than handmade method. Furthermore, the mechanical properties and microstructures of the specimens made by handmade method and press molding method were almost same.

The residual strength of dental porcelain discs were test after cycling fatigue compressive load in this study. Moreover, the effects of stress intensity and cycle frequency to the damage of porcelain were explored. The porcelain specimens were bonded to the epoxy resin blocks, with 12.5mm height. The cycling fatigue contact loads were subjected on the porcelain surfaces of the bi-layer composites with silicon nitride spheres of radius 2.5mm. The crosshead speed was 6mm/min. The top load value was varied from 10N-20N in every load cycles. The cycling number was from 50-300. After cycling test, the residual strength of all porcelain samples was measured by bi-axial bending test. Fractured pieces of the specimens were collected and examined with optical microscope and SEM. On the fracture surfaces of porcelain discs after bi-axial bending test, Hertz cone cracks were presented due to cycling fatigue load. The result showed that the residual strength of dental porcelain had negative correlation with the fatigue load values and cycles. When the fatigue load cycles were lower than 100, the residual strength of porcelain presented no significant different under 10 or 20N fatigue load. In contrary, when the fatigue load cycles were over 100, the residual strength of porcelain was much lower under 20N fatigue load than 10N fatigue load. Based on the limited results of this study, the conclusion could be drawn that the residual strength of porcelain under fatigue compressive stress was main determined by load cycles in the range of small load values. The porcelain could be destroyed after very few cycles if the load is up to a critical value.

Traditional Chinese Medicine (TCM) therapies should be tailored according to the different syndrome types. In order to identify the relationship between the TCM Yin-cold (YC) or Yang-heat (YH) syndrome types and the EGFR gene status, we prospectively studied 310 NSCLC patients. TCM YH or YC was diagnosed by three TCM experts. TCM symptoms and signs were entered into a binary cluster analysis. The relationships between the EGFR gene status, YH or YC syndrome types, and classification by cluster analysis were analyzed using the chi-square test and multivariate logistic regression. In the 299 patients who had their EGFR gene tested, 45.24% YC (76/168) and 25.95% YH (34/131) patients had EGFR mutations (p=0.001). Among the 292 patients entered into the cluster analysis, 132 were classified into group A, with signs and symptoms similar to YC, whereas 160 group B patients were similar to YH. In the 281 patients with EGFR tested, 45.67% group A (58/127) and 28.57% group B patients (44/154) had EGFR mutations (p=0.003). The EGFR status was independently correlated with TCM syndrome type and classification by cluster analysis on multivariate logistic regression. NSCLC patients with YC were more likely to have EGFR gene mutations.

// Yan-juan Zhu 1 , Hai-bo Zhang 1 , Yi-hong Liu 1 , Fu-li Zhang 1 , Ya-zhen Zhu 2 , Yong Li 1 , Jian-ping Bai 1 , Li-rong Liu 1 , Yan-chun Qu 1 , Xin Qu 1 , Xian Chen 1 , Yan Li 1 , Guang-juan Zheng 2 1 Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangdong Provincial Hospital of Chinese Medicine, China 2 Pathology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangdong Provincial Hospital of Chinese Medicine, China Correspondence to: Hai-bo Zhang, email: haibozh@aliyun.com Keywords: droplet digital polymerase chain reaction, epidermal growth factor receptor, non-small cell lung cancer, blood biopsy Received: October 25, 2016 Accepted: December 16, 2016 Published: January 04, 2017 ABSTRACT Detection of circulating tumor DNA using droplet digital polymerase chain reaction (ddPCR) is a highly-sensitive, minimally invasive alternative to serial biopsies for assessment and management of cancer. We used ddPCR to assess the utility of measuring plasma concentrations of common epidermal growth factor receptor ( EGFR ) mutations (L858R, exon 19 deletion, and T790M) in 57 non-small cell lung cancer (NSCLC) patients treated with EGFR tyrosine kinase inhibitors (EGFR-TKIs). High baseline plasma EGFR mutation ( pEGFRmut ) concentrations were associated with shorter progression-free survival (8.43 months) than low baseline pEGFRmut (16.23 months; p = 0.0019). By contrast, there were no differences in tumor shrinkage or overall survival between groups. During EGFR-TKI treatment, pEGFRmut levels decreased to zero in 89.58% of patients. Twenty-five of the 27 patients who progressed had basal pEGFRmut , and 18 also had circulating T790M. All 20 patients with dramatic progression (according to a categorization system for EGFR-TKIs failure) had basal pEGFRmut , and 13 had T790M mutation at progression. These results support the use of ddPCR for analysis of plasma EGFR mutations for prediction of PFS and to monitor clinical responses to EGFR-TKIs in NSCLC patients.

The paper is to design and implement parallel operation of paralleled inverters with interleaved phase shift. For parallel operation, one inverter is used as master module to transmit synchronization signals to trigger the external interrupts of two microcontrollers for synchronous operation to slave module. In this paper, the design of voltage controlled loop feedback controller by proportional-integral controller is employed to have fast transient response with different load conditions. It is proposed that interleaved phase shift for parallel inverters could reduce output voltage ripple of inverter and increase the system response. The experimental results show that the proposed inverter provided a voltage output with low harmonic distortion by the proposed interleaving phase-shift parallel inverter scheme.

Reaction of the bis-aminophosphinimine [m-C6H4(HNCH2CH2N═PPh3)] with W(CO)6 afforded [m-C6H4{(CNCH2CH2NH)W(CO)5}2] (2), which underwent N-alkylation with benzyl bromide to yield [m-C6H4{(CNCH2CH2NCH2Ph)W(CO)5}2] (3). A carbene transfer reaction from W(0) to Ir(I) proceeded smoothly via the reaction of 3 with [Ir(COD)Cl]2 under mild conditions to give the diiridium(I) carbene complex [m-C6H4{(CNCH2CH2NH)Ir(CO)2Cl}2] (4). Ligand substitution of 4 with an excess of PPh3 produced the phosphine complex 5. All complexes have been characterized by spectroscopic and elemental analyses. Complexes 2 and 5 were further confirmed by X-ray diffraction studies. Complex 4 is an efficient catalyst for the reductive N,N′-dialkylation of phenylenediamines with alcohols. The mechanistic pathway of the catalysis involving the possible synergistic effect between two metal centers is discussed.

For more than a century, hydrogen sulfide (H(2)S) has been regarded as a toxic gas. This review surveys the growing recognition of the role of H(2)S as an endogenous signaling molecule in mammals, with emphasis on its physiological and pathological pathways in the cardiovascular system. In biological fluids, H(2)S gas is a weak acid that exists as about 15% H(2)S, 85% HS(-), and a trace of S(2-). Here, we use "H(2)S" to refer to this mixture. H(2)S has been found to influence heart contractile functions and may serve as a cardioprotectant for treating ischemic heart diseases and heart failure. Alterations of the endogenous H(2)S level have been found in animal models with various pathological conditions such as myocardial ischemia, spontaneous hypertension, and hypoxic pulmonary hypertension. In the vascular system, H(2)S exerts biphasic regulation of a vascular tone with varying effects based on its concentration and in the presence of nitric oxide. Over the past decade, several H(2)S-releasing compounds (NaHS, Na(2)S, GYY4137, etc.) have been utilized to test the effect of exogenous H(2)S under different physiological and pathological situations in vivo and in vitro. H(2)S has been found to promote angiogenesis and to protect against atherosclerosis and hypertension, while excess H(2)S may promote inflammation in septic or hemorrhagic shock. H(2)S-releasing compounds and inhibitors of H(2)S synthesis hold promise in alleviating specific disease conditions. This comprehensive review covers in detail the effects of H(2)S on the cardiovascular system, especially in disease situations, and also the various underlying mechanisms.

Recently bipolar phosphorescent host materials have attracted wide attention since they can achieve better charge balance and hence better device performance. In this work, we report the synthesis and physical properties of a novel bipolar host material containing the dimesityl borane/carbazole hybrid, CMesB. With a high triplet energy, CMesB is considered a promising universal host material and has been applied to phosphorescent OLEDs of various colors. Red/green/blue/white (RGBW) OLEDs based on CMesB all show high external quantum efficiencies (20.7% for red, 20.0% for green, 16.5% for blue, and 15.7% for white) at practical brightnesses. The results indicate that the bipolar host CMesB with high triplet energy has high potential in manufacturing RGBW OLEDs for display or lighting applications.

The coordination chemistry of RuII ions with [2-(diphenylphosphanyl)-N-(o-hydroxybenzylidene)]aniline (PNO-H) and the methylated analogue PNO-Me have been studied. Thus, [(PNO)RuCl(dmso)2] (1), [(PNO)2Ru] (2), [(PNO)RuCl(PPh3)] (3) and [(PNO)RuCl(CO)2] (4) were synthesized by reactions of various RuII precursors with PNO-H. Treatment of PNO-Me with [RuCl2(dmso)4] resulted in in the formation of [P,N-(PNO-Me)Ru(dmso)2Cl2] (5). However, complexation of PNO-Me with [RuCl2(CO)3(THF)] (THF = tetrahydrofuran) provided a mixture of [P,N-(PNO-Me)Ru(CO)2Cl2] (6) and 4 because O-demethylation took place during the reaction. All of the RuII complexes have been characterized by elemental analysis and spectroscopic techniques, as well as X-ray crystal structural analysis for 2, 4 and 6. The ruthenium complexes investigated in this work, except 2, are good precatalysts for the reductive amination of amine with alcohols, and 4 appears to be the best. Moreover, 4 can catalyze the direct amination of nitrobenzene with benzyl alcohol to the corresponding secondary amine.

Bi-layer all-ceramic dental crowns comprise an inner core made of alumina or zirconia and an outer porcelain shell. The veneer safe from damage is mainly depended on the properties of core materials due to the poor strength and toughness of porcelain. The fracture modes and crack transformation of zirconia/porcelain and alumina/porcelain bi-layer composites reveal the potential feasibilities of improving the fatigue life of all-ceramic restorations. The failure modes of bi-layer composites were confirmed under cyclic spherical fatigue loading by dynamic microcosmic observation. Crack modes and evolvement of bi-layered composites were explored inflecting with fatigue load, cycles, frequency and water environment. Microcosmic morphology of the samples was observed by high depth of field stereomicroscope to determine degree and modes of fatigue damage. The appearance of cone cracks of porcelain surface was almost consistent in both of zirconia and alumina bi-layer composites. However, the pattern and process of the damage are different under cycle fatigue load. Furthermore, process of fatigue damage of bi-layer composites were observed to failure rapidly under water environment in both of zirconia and alumina bi-layer composites.

In this study, ZnO sol was prepared by sol-gel method with zinc acetate, triethanolamine and sodium hydroxide as the main material. Then obtained ZnO sol was directly blended with polyacrylate latex to prepare polyacrylate/ZnO nanocomposite. The effects of ZnO sol contents on the mechanical properties and water absorption of polyacrylate/ZnO nanocomposite were investigated in details. The results showed tensile strength of polyacrylate/ZnO nanocomposite reduced, and water absorption of it increased with the increasing of ZnO sol. Transmission electron micrograph (TEM) analysis indicated ZnO sol dispersed uniformly and the size of it was about 20nm. Scanning electronic microscope (SEM) analysis showed ZnO sol and polyacrylate have good compatibility, however, ZnO sol would condensate and form short rods structure during the film forming process.

The reaction of [Ru]-Cl ([Ru] = Cp(PPh3)2Ru) with o-ethynyl-substituted methyl benzoate, followed by a sequential deprotonation and electrophilic alkylation reactions by further reacting with base and various alkyl haloacetates, respectively, generated several disubstituted ruthenium vinylidene complexes. In the deprotonation reactions of these disubstituted vinylidene complexes containing two ester groups, tandem cyclizations of the ligand is accompanied with a methanol elimination to generate a new organometallic product containing a three-ring indenofuranone ligand, which structure has been confirmed by a single-crystal X-ray diffraction analysis. Facile protonation and methylation are observed in these indenofuranone complexes. Additionally, for the simple furyl complex containing an O-benzyl group, a 1,3-migration of the benzyl group is observed to yield a lactone product and a Claisen rearrangement is also observed in analogous complexes with O-allyl or O-propargyl groups.

Hydrogen sulfide (H(2)S), an endogenously produced gasotransmitter, which is soluble in both water and lipids, is now known for its protective effects against various disease models and cellular injuries. A wide range of studies have been published on the protective effects of H(2)S against ischemia-reperfusion injuries, with findings focusing mainly on the heart and liver. It was not until recently that the effect of H(2)S on kidneys gained the attention and interest of researchers, and studies have begun to unveil the role of H(2)S under physiological conditions, as well as during pathological renal diseases. This article will provide a summary of current research findings on the relationship between H(2)S and the kidneys, based on existing literature, with prime emphasis on renal ischemia-reperfusion injuries. In this article, a brief discussion will be dedicated to providing insight of the currently known signaling mechanisms underlying the protective effects of H(2)S in the kidneys.

Glass/ zirconia laminated material is the most commonly used material in the field of dental restoration, although the biocompatibility of such material has been subject to lots of research and the mechanical compatibility and durability have not been deeply researched. This paper, by the research on the contact stress of static and dynamic surfaces of the ceramic material, reveals the physical meaning of damage and fatigue at the interface of material; through contacting with the sphere indentation test and by the investigation of fatigue and damage of the surface and interface of such material in the corresponding time scale as well as by the use of acoustic emission monitoring for detecting the damage process and crack propagation process within the detection layer and the laminated ceramic surface, the time of occurrence and corresponding load can be obtained, which plays an importantly practical role in resolving the forecasting of the changes in material damage and the analysis of fatigue.

Reaction of the ruthenium allenylidene complex [Ru]═C═C═CPh2 (1, [Ru] = Cp(PPh3)2Ru) with the propargylic Grignard reagent R-C≡CCH2MgBr (R = CH3, CH2CH3, Ph) yielded a mixture of two acetylide comp...

The cyclization reaction of several diallyl aromatic amine molecules, each containing an ethynyl group at the ortho position of the aromatic ring, is accompanied by an aza-Claisen rearrangement, causing an allyl group migration to give substituted indole compounds. This cyclization is catalyzed by ruthenium triphenylphosphine and diphenylphosphinoethane (dppe) complexes as well as gold complexes with silver reagent. The less sterically crowded dppe complex is a more efficient catalyst. The mechanism involving a vinylidene intermediate is proposed on the basis of isolation of several intermediates in the ruthenium-catalyzed system. Single crystals of a metal complex with the cyclized ligand were obtained, and the structure was determined by an X-ray diffraction analysis.

Hydrogen sulfide (H2S), an endogenous gaseous mediator, produces both vasorelaxation and vasoconstriction at different concentrations. We found in the present study that NaHS, an H2S donor, produced stronger vasorelaxant and weaker vasoconstrictive effects in HEPES solution compared with those achieved in Krebs solution. We further screened the buffer components and found that bicarbonate (HCO3−) was the ion to influence the effect of H2S. After examining the vasorelaxant effects of acetylcholine, a vasodilator by releasing nitric oxide, and isoprenaline, a β-adrenoceptor agonist, in HEPES and Krebs buffers, we found the HCO3−-dependent effect was specific to H2S. Blockade of anion exchanger-2 activity with 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS) or with HCO3−-free solution abolished the vasoconstrictive effect of NaHS. Moreover, NaHS decreased nitric oxide level in the rat aorta in HCO3−-containing buffer, but this effect was abolished by HCO3−-free buffer or DIDS. In summary, we found for the first time that H2S stimulates anion exchanger to transport extracellular HCO3−in exchange for intracellular superoxide anions, which may further inactivate nitric oxide and induces vasoconstriction.

Condensation of tetraphenylporphyrin-2,3-dione with 1,10-phenanthroline-5,6-diamine provided porphyrinphenanthroline (2) as the desired ligand. Metallation of the porphyrinic site of 2 with CoCl2, NiCl2, ZnCl2 and CuCl2 afforded the corresponding metal complexes [Co(2)] (8a), [Ni(2)] (8b), [Zn(2)] (8c) and [Cu(2)] (8d), respectively. Subsequent reactions of these metalloporphyrins with [(COD)PdCl2] yielded the corresponding bimetallic complexes [Co/Pd (9a), Ni/Pd (9b), Zn/Pd (9c) and Cu/Pd (9d)] in high yields. The bimetallic complex 9e (Mg/Pd) was prepared directly by complexation of 2 with MgBr2 and [(COD)PdCl2]. All complexes were characterized by both spectroscopic and elemental analyses. In addition, crystal structure of 9c was determined to confirm its formulation. The use of these bimetallic complexes as pre-catalysts for Mizoroki–Heck coupling reaction has been examined.

A formal intramolecular olefin metathesis process between the C═C double bond of a vinylidene ligand and a pendant vinyl group in several ruthenium complexes, each with a ferrocenyl group, is followed by an additional intramolecular C−C bond formation between a Cp ligand of the ferrocenyl substituent and the vinylidene ligand. The regioselectivity of the C−C bond formation reaction at either the substituted or the nonsubstituted Cp group of the ferrocenyl group is possibly influenced by a steric effect between the neighboring substituent near the ferrocenyl group and the phosphine ligand on the ruthenium metal center. The structure of one ruthenium complex resulting from such a C−C bond formation has been fully characterized by a single-crystal X-ray diffraction analysis.

Reactions of the four 1,6-diynes 1−3 and 7, each with one terminal propargylic alcohol and one internal triple bond containing Me3Si groups, with [Ru]−Cl ([Ru] = Cp(PPh3)2Ru) led to two types of products. In the first type, only the propargylic group is involved in the reaction leading to vinylidene, allenylidene, or acetylide complexes. A C−C bond formation of two triple bonds in 1,6-diynes gave allylcarbene products of the second type. The reaction of 1 with [Ru]−Cl yielded only the first type, giving a mixture of two cationic complexes; the allenylidene complex 8 and the phosphonium acetylide complex 9, the latter resulting from further addition of a phosphine molecule to Cγ of 8. The same reaction in the presence of excess phosphine gave 9 only. However, with an additional methyl group, the 1,6-diyne 2 reacted with [Ru]−Cl to give the allylcarbene complex 11 also with a phosphonium group on the ligand. The reaction proceeds by a cyclization reaction involving two triple bonds on the metal accompanied ...

Iridium complexes [(CO)(2)Ir(NHC-R)Cl] (R = Et-, 3a; PhCH2-, 3b; CH3OCH2CH2-, 3c; o-CH3OC6H4CH2-, 3d; NHC: N-heterocyclic carbene) are prepared via the carbene transfer from [(NHC-R)W(CO)(5)] to [Ir(COD)Cl](2). By using substitution with (CO)-C-13, we are able to estimate the activation energy (Delta G double dagger) of the CO-exchange in 3a-d, which are in the range of 12-13 kcal mol(-1), significantly higher than those for the phosphine analog [(CO)(2)Ir(PCy3)Cl]. Reactions of 3b and 3d with an equimolar amount of PPh3 result in the formation of the corresponding [(NHC-R)Ir(CO)(PPh3)Cl] with the phosphine and NHC in trans arrangement. In contrast, the analogous reaction of 3a or 3c with phosphine undergoes substitution followed by the anion metathesis to yield the corresponding di-substituted [(NHC-R)Ir(CO)(PPh3)(2)]BF4 (5) directly. Treatment of 3b or 3d with excess of PPh3 leads to the similar product of disubstitution 5b and 5d. The analysis for the IR data of carbonyliridium complexes provides the estimation of electron-donating power of NHCs versus phosphines. The NHC moiety on the iridium center cannot be replaced by phosphines, even 1,2-bis(diphenylphohino)ethane (dppe). All the carbene moieties on the iridium complexes are inert toward sulfur treatment, indicating a strong interaction between NHC and the iridium centers. Complexes 3a-c are active on the catalysis of the oxidative cyclization of 2-(o-aminophenyl)ethanol to yield the indole compound. The phosphine substituted complexes or analogs are less active.

Both saturated and unsaturated N-benzyl substituted heterocyclic carbene (NHC) iridum(i) complexes were synthesized. The unsaturated carbene complex [(un-NHC-Bn)Ir(CO)(2)Cl] in the cis form was prepared via the carbene transfer from the corresponding silver complex to [Ir(COD)(2)Cl](2) followed by ligand substitution with CO, whereas the saturated complex was obtained via the transfer from (sat-NHC-Bn)W(CO)(5). The treatment of phosphines with (NHC)Ir(CO)(2)Cl complexes yielded the products with the phosphine ligand trans to the carbene moiety via substitution. X-Ray structural determination shows that distances of Ir-C((carbene)) in both (un-NHC-Bn)Ir(CO)(PR(3))Cl and (un-NHC-Bn)Ir(CO)(PR(3))Cl are essentially the same. Analyses of spectroscopic and crystal structural data of iridium complexes [(NHC)Ir(CO)(PR(3))Cl] and Vaska's complex show similar corresponding data in both types of complexes, suggesting that the studied NHC ligands and phosphines have similar bonding with Ir(i) metal center. All iridium complexes studied in this work illustrated their catalytically activity on N-alkylation of amine with alcohol via hydrogen transfer reduction. It appears no dramatic difference on the catalytic activity among these iridium carbene complexes; but the saturated carbene complex (sat-NHC-Bn)Ir(CO)(PR(3))Cl appears to be slightly more active. For example, the reaction of benzyl alcohol with aniline in the presence of catalyst (1 mol%) under basic conditions at 100 degrees C provided the secondary amine (N-benzylaniline) in 96% yield.

Glass-alumina bi-layer composite was widely used as dental materials, the reliability and mechanical properties are very important for its practical application. In this work, residual stresses in dental glass-alumina composite and failure mechanism were investigated through finite element analysis and 3-point and ball-on-ring bending tests, respectively. The mechanical behavior of the dental material was studied using the bending tests and indentation method. Small bi-layer disk specimens were prepared for the axis-symmetrical tests using a set of small device in a universal tester. The results indicate that the difference in thermal expansion coefficients between two layers lead to residual stresses in both layers, and the stresses distribution depends on the thickness ratio and temperature difference. Furthermore, a proof testing method was proposed to estimate the workability and reliability of the dental ceramics.

In an investigation into the chemical reactions of N-propargyl pyrroles 1 a-c, containing aldehyde, keto, and ester groups on the pyrrole ring, with [Ru]-Cl ([Ru]=Cp(PPh3 )2 Ru; Cp=C5 H5 ), an aldehyde group in the pyrrole ring is found to play a crucial role in stimulating the cyclization reaction. The reaction of 1 a, containing an aldehyde group, with [Ru]-Cl in the presence of NH4 PF6 yields the vinylidene complex 2 a, which further reacts with allyl amine to give the carbene complex 6 a with a pyrrolizine group. However, if 1 a is first reacted with allyl amine to yield the iminenyne 8 a, then the reaction of 8 a with [Ru]-Cl in the presence of NH4 PF6 yields the ruthenium complex 9 a, containing a cationic pyrrolopyrazinium group, which has been fully characterized by XRD analysis. These results can be adequately explained by coordination of the triple bond of the propargyl group to the ruthenium metal center first, followed by two processes, that is, formation of a vinylidene intermediate or direct nucleophilic attack. Additionally, the deprotonation of 2 a by R4 NOH yields the neutral acetylide complex 3 a. In the presence of NH4 PF6 , the attempted alkylation of 3 a resulted in the formation the Fischer-type amino-carbene complex 5 a as a result of the presence of NH3, which served as a nucleophile. With KPF6, the alkylation of 3 a with ethyl and benzyl bromoacetates afforded the disubstituted vinylidene complexes 10 a and 11 a, containing ester groups, which underwent deprotonation reactions to give the furyl complexes 12 a and 13 a, respectively. For 13 a, containing an O-benzyl group, subsequent 1,3-migration of the benzyl group was observed to yield product 14 a with a lactone unit. Similar reactivity was not observed for the corresponding N-propargyl pyrroles 1 b and 1 c, which contained keto and ester groups, respectively, on the pyrrole ring.

Reaction of o-(diphenylphosphino)(N-benzylidene)aniline (P∼N) with [Ir(COD)Cl]2 affords the substitution product [(P∼N)Ir(COD)Cl] (1). Treatment of 1 with AgBF4 yields the cyclometalated iridium hydride complex [P,N,C-(P∼N)Ir(COD)H]BF4 (2). On the other hand, under atmospheric pressure of CO, carrying out the substitution of [Ir(COD)Cl]2 with P∼N results in the formation of [P,N,C-(P∼N)Ir(CO)HCl] (5). Conversion of 4 into 5 can be achieved by the reaction of 4 with CO in the presence of tetraethylammonium chloride. Both 4 and 5 are characterized by spectroscopic and X-ray structural analyses. All iridium complexes are not good catalysts for hydroamination. However, the combination of 5 with NaB[3,5-C6H3(CF3)2]4 (denoted as NaBArF4) provides a potent catalytic system for both intra- and intermolecular hydroamination of alkynes. Intramolecular reaction of o-(2-phenylethynyl)anilines produces the corresponding indoles in good yields. Furthermore, intermolecular hydroamination takes place smoothly to generate...

Surface and subsurface contact damage in dental ceramics and the influence of microstructure on damage tolerance were investigated in this study through indentation methods. The dependence of the damage tolerance on common materials properties was discussed. A simple expression to estimate quantitatively the damage tolerance via basic material parameters, based on the features of damage tolerance and fracture mechanics is confirmed. And the residual strength of damaged specimen was measured via three-point bending tests.

Coordination chemistry of a new pyridine imidazole-2-ylidene ligand (pyN∧C) system with sterically hindered substituents toward rhodium(I) metal ions has been investigated. The rhodium complex [(pyN∧C)RhCl(COD)] (COD = 1,5-cyclooctadiene) was prepared via the transmetallation from the silver complex [(C-pyN∧C)2Ag]AgI2. Upon the abstraction of chloride, the pyridinyl nitrogen coordinated to the metal center and formed [(C,N-pyN∧C)Rh(COD)]BF4 with the chelation of pyN∧C. The pyridinyl nitrogen donor was found to be labile and could be replaced by various donors such as phosphine, azide and halides. Substitution of COD by various donors does not proceed except strong π-acid ligands such as CO and P(OCH3)3. However, the chelation of pyN∧C was replaced by the bisphosphine (P∼P) to form [(P∼P)2Rh]BF4, which was subsequently oxidized to yield [(P∼P)2Rh(O2)]BF4.

Coordination of a chiral arsine–oxazoline ligand ( As – N ) toward (COD)PdCl 2 and (COD)PdMeCl leading to ( As – N )PdCl 2 ( 3 ) and ( As – N )PdMeCl ( 4 ) were reported. Both 3 and 4 were characterized by spectroscopic and X-ray single crystal diffraction methods. Treatment of 4 with AgBF 4 in the presence of acetonitrile resulted in the formation of [( As – N )PdMe(CH 3 CN)]BF 4 ( 6 ). Complex 6 catalyzed the copolymerization of CO and olefin, but in low conversions. In fact, the palladium black and [( As – N ) 2 Pd](BF 4 ) 2 ( 7 ) were formed from the copolymerization processes, which may explain the lower catalytic activity of 6 . Crystal structure of 7 was also determined.

Formation of mono- and dinuclear complexes containing ligands stemmed from the condensation of 2,6-diformyl-4-methylphenol derivatives with 2-(diphenylphosphino)aniline (P∼N) was investigated. Condensation of P∼N with 2,6-diformyl-4-methylanisole yielded the desired bis(imine-phosphine) L3, but provided the cyclized benzoazaphospholium compound with 2,6-diformyl-4-methylphenol. Complexation of L3 with (COD)PdCl2 gave the dinuclear complex 4. On the other hand, L3 underwent the intramolecular cyclization in the presence of (DME)NiCl2 via the formation of benzoazaphospholium rings. Template condensation of 2,6-diformyl-4-methylphenol with P∼N in the presence of metal ions yielded the mononuclear nickel(II) and palladium(II) complexes, respectively.

Dinuclear ruthenium cyclopropenyl complexes ([Ru] = (η5-C5H5)(PPh3)2Ru, R = CN, 3a; R = CH2CH2, 3b; R = Ph, 3c) are prepared by deprotonation of corresponding vinylidene complexes {[Ru]CC(CH2R)}2C6H42+ (2). For the vinylidene complex 2d (R = CO2Me) with an ester group, the deprotonation reaction leads to formation of the dinuclear bis-furyl complex (5d). Electrophilic addition of TCNQ to both three-membered rings of 3a yields the zwitterionic bis-vinylidene complex {[Ru]CC[CH(TCNQ)CN]}2C6H4 (4a), which, in the presence of MeOH/n-Bu4NOH, gives the methoxy-substituted bis-cyclopropenyl complex (6a). The proton-induced demethoxylation of 6a generates (7a). The reaction of TMSN3 with 3a gives the bis-tetrazolate complex {[Ru](N4C)CH(CH2CN)}2C6H4 (8a). Trinuclear tris-cyclopropenyl complexes (R = CN, 11a; R = CH2CH2, 11b; R = Ph, 11c) are obtained from deprotonation of {1,3,5-{[Ru]CC(CH2R)C6H4C⋮C}3C6H3}3+ (10). Complex 2b is characterized by X-ray diffraction analysis, and other complexes are characterized by ...

Palladium complexes [(P∼N∼O)PdR]BF 4 containing imine-phosphine-ether tridentate donor were prepared. The behavior of an ether donor, a hemi-labile one, influences the coordination mode of a carbon ligand around the metalcenter. Reaction of excess styrene with [(P∼N∼O)PdMe]BF 4 results in the formation of [(P∼N∼O)Pd(η 3 -CH(CH3)C 6 H 5 )] BF 4 , which is characterized by spectral and crystal structural determination. Copolymerization of olefin and carbon monoxide catalyzed by [(P∼N∼O)PdMe]BF 4 is addressed.

To evaluate the precision of digital impressions taken under simulated clinical impression taking conditions with TRIOS and to compare with the precision of extraoral digitalizations.Six #14-#17 epoxy resin dentitions with extracted #16 tooth preparations embedded were made. For each artificial dentition, (1)a silicone rubber impression was taken with individual tray, poured with type IV plaster,and digitalized with 3Shape D700 model scanner for 10 times; (2) fastened to a dental simulator, 10 digital impressions for each were taken with 3Shape TRIOS intraoral scanner. To assess the precision, best-fit algorithm and 3D comparison were conducted between repeated scan models pairwise by Geomagic Qualify 12.0, exported as averaged errors (AE) and color-coded diagrams. Non-parametric analysis was performed to compare the precisions of digital impressions and model images. The color-coded diagrams were used to show the deviations distributions.The mean of AE for digital impressions was 7.058 281 μm, which was greater than that of 4.092 363 μm for the model images (P0.05). However, the means and medians of AE for digital impressions were no more than 10 μm, which meant that the consistency between the digital impressions was good. The deviations distribution was uniform in the model images,while nonuniform in the digital impressions with greater deviations lay mainly around the shoulders and interproximal surfaces.Digital impressions with TRIOS are of good precision and up to the clinical standard. Shoulders and interproximal surfaces scanning are more difficult.

Pyrazole-1-carboxamidine and formamidinesulfinic acid do not react because of the decomposition of the substrates under this conditions.