Ru-Mg promoted reductive cross-coupling of allyl bromides and alkenes to synthesize 1,7-octadienes with an all-carbon quaternary center.

A Ru-promoted reductive cross-coupling of allyl bromides and electron-deficient alkenes to provide terminal 1,7-octadienes with magnesium as a reductant is reported herein. This approach enables the facile construction of a series of complex terminal 1,7-octadienes with an all-carbon quaternary center under mild reaction conditions, and the synthetic utility of the current method has been demonstrated by a gram scale synthesis. Preliminary mechanism investigations suggested that a radical pathway might not be involved in this transformation.

Controlled Synthesis of α-CF2H or α-CF2Cl Styrenes from the Same Precursors: Dehydrazinative Hydrogenation or Chlorination of 3,3-Difluoroallyl Hydrazines.

By carefully choosing the reaction conditions, we have developed the controllable FeCl3- or CuCl2-mediated dehydrazinative hydrogenation or chlorination of 3,3-difluoroallyl hydrazines to access α-CF2H or α-CF2Cl styrenes. The current reaction provides for the first time a facile method for the direct and selective synthesis of α-CF2H and α-CF2Cl styrenes starting from the same precursors, which is easy to scale up and displays a broad substrate scope and good functional group tolerance. Moreover, product derivatization experiments demonstrated that the resulting α-CF2Cl styrenes are practical and versatile building blocks for the diversified synthesis of fluorinated molecules.

Novel electrochemical sensing platform basing on di-functional stimuli-responsive imprinted polymers for simultaneous extraction and determination of metronidazole.

A novel magnetic-controlled electrochemical sensor has been fabricated by combined photo-responsive surface molecular imprinted polymers (P-SMIPs) and electrochemical sensor. In particular, the P-SMIPs were obtained by living radical polymerization of photo-responsive functional monomer onto the magnetic Fe3O4 modified multi-walled carbon nanotubes nanocomposites. The magnetic glassy carbon electrode was introduced to make the anchoring and removal of P-SMIPs onto the magnetic-controlled glassy carbon electrode easy to manipulate. Driven by UV/vis light, the platform performs releasing and absorption of metronidazole basing on conformational variations of the photo-responsive monomer at the receptor sites part in the P-SMIPs. This process can be tested by the photo-responsive variations of metronidazole electrochemical signal. As the consequence, extracting of P-SMIPs sensor can be conveniently triggered by the controllable UV light intervention measure, leading to effectively improve in both analytes mass transfer rate to the receiving media and extraction efficiency. The experimental result indicated that the excellent recoveries of metronidazole were varied between 77.9% and 89.9% with RSDs ≤4.87% in the biological samples. Therefore, the P-SMIPs sensor shows satisfactory potential in reusable extractions that can be recycled several times with no significant loss of activity, and this utilization strategy can be extended to other analytes, achieving manifold applications of pharmaceutical and environmental.

Self-cleaning electrochemical protein-imprinting biosensor with a dual-driven switchable affinity for sensing bovine serum albumin.

A facile, universal and highly efficient approach for producing a self-cleaning electrochemical protein-imprinting biosensor based on dual stimuli-responsive memory hydrogels via free-radical polymerisation is described. As confirmed by static contact angle and scanning electron microscopy results, the imprinted hydrogels exhibited reversible conformational changes after being simulated by an external electric field and temperature. By exploring the properties of imprinted hydrogels for sensing applications, the electrochemical protein-imprinting biosensor was originally fabricated on a glassy carbon electrode using the drop-casting method. Because of the trigger gates of the temperature and electric field, the biosensor demonstrated excellent self-cleaning behaviours compared with other corresponding electric-field or thermo-responsive imprinting biosensors. Moreover, the prepared biosensor exhibited satisfactory selectivity, good biocompatibility, comparable limits of detection and linearity ranges as well as acceptable stability toward bovine serum albumin. Consequently, the biosensor was successfully employed to simultaneously enrich, detect and extract bovine serum albumin from complex biological samples; the process was dynamic, controllable and harmless to the template under the dual external stimuli. Thus, the proposed biosensor exhibited considerable potential in controlled drug/chemical delivery and smart sensing for bioanalyses involving dual stimuli-responsive behaviours.

Comparative morphology of the internal elastic lamina of cerebral and peripheral arteries.

BACKGROUND: Atherosclerosis progresses later and with fewer complicated plaques in cerebral arteries than in peripheral arteries. The internal elastic lamina has been proposed to be important for the migration of smooth muscle cells into the intima during intimal thickening and atherosclerosis. METHODS: A total of 280 segments were retrieved from 14 autopsy specimens. Five sites were selected for analysis in each case: the middle cerebral artery, basilar artery, coronary artery, iliac artery and renal artery. We investigated the differences in the internal elastic lamina of cerebral and peripheral arteries. RESULTS: The average thickness of the internal elastic lamina of the cerebral arteries was larger than that of the peripheral arteries in both the early and advanced atherosclerotic plaque groups. Among the cerebral arteries, the basilar arteries had a thicker internal elastic lamina than the middle cerebral arteries. Among the peripheral arteries, the renal arteries had the thickest internal elastic lamina, followed by the iliac arteries and coronary arteries. Atherosclerosis led to a reduction in the thickness of the internal elastic lamina of the basilar, middle cerebral, and renal arteries. The stratification of the internal elastic lamina of iliac arteries significantly affected its measurement. The internal elastic lamina of coronary arteries was not affected by atherosclerosis, but it appeared fragmented. CONCLUSION: The results suggest that the characteristics of atherosclerotic plaques in cerebral and peripheral arteries may be related to the characteristics of the internal elastic lamina.

gem-Difluoroallylation of Aryl Diazoesters via Catalyst-Free, Blue-Light-Mediated Formal Doyle-Kirmse Reaction.

A first example of low-energy blue-light-mediated formal Doyle-Kirmse reaction for gem-difluoroallylation of aryl diazoesters has been developed. A variety of highly functionalized gem-difluoroallyl containing esters bearing transformable sulfur and bromine groups were efficiently assembled with broad substrate scope under mild, catalyst-free, and additive-free conditions. The reaction represents a practical and environmentally friendly approach for C-CF2 bond formation based on rearrangement strategy, which will find potential applications among drug discovery and development.

Supramolecularly imprinted polymeric solid phase microextraction coatings for synergetic recognition nitrophenols and bisphenol A.

We herein firstly presented supramolecularly imprinted polymeric (SMIP) solid phase microextraction (SPME) coatings which showed synergetic recognition for nitrophenols and bisphenol A. A series of ß-cyclodextrins (ß-CD) with different substituents were successfully designed and synthesized. It was employed as supramolecular functional monomers for SMIPs. The orderly assembling structures settled down under the molecular imprinting process. The four of SMIPs solid phase microextraction coatings showed good selectivity for the template and could be used to extract 4-NP in real water samples. Furthermore, the inclusion effects of derived ß-CDs with the 4-NP were investigated by measuring the UV-vis spectra and the theoretical calculations. The strongest intermolecular force is come from the supramolecular complex of 4-NP and ß-CD-4 which shows the strongest UV-vis spectra absorption value. Meanwhile, the difference of the theoretical calculations value coming from the system of derived ß-CDs and 4-NP is the largest, revealing the strongest electronic interactions between derived ß-CD-4 and 4-NP. Therefore, these polymers possess inclusion interactions from ß-cyclodextrin cavities and hydrogen-bonding interactions from molecular imprinting. Multiple adsorptions triggered off a synergetic recognition for target analytes. The SMIPs also performed highly selective recognition in complex real water sample with sensitive detection limits.

Copper-Catalyzed Dehydrogenative Formal [4 + 2] and [3 + 2] Cycloadditions of Methylnaphthalenes and Electron-Deficient Alkenes.

Higher π-extended naphthalene, contained in methylnaphthalenes, which could capture alkyl radicals via SOMO-LUMO interactions, enabled the development of Cu-catalyzed formal [4 + 2] and [3 + 2] cycloadditions between methylnaphthalenes and electron-deficient alkenes. Under copper catalysis, a series of electron-deficient alkenes and methylnaphthalenes with different substituents were successfully incorporated with di-tert-butyl peroxide (TBP) as an oxidant and radical initiator, providing a wide range of cycloadducts.

Silver-catalyzed nucleophilic substitution of aminals with ethyl diazoacetate: a new pathway to ß-amino-α-diazoesters.

A novel silver-catalyzed nucleophilic substitution of aminals with ethyl diazoacetate producing ß-amino-α-diazoesters has been developed. A series of aminals with different amino moieties and substituents were successfully incorporated in this reaction, which delivered a wide range of ß-amino-α-diazocarbonyl compounds in the presence of a lower catalyst loading in 2 hours.

The Diagnostic Value of Gastrin-17 Detection in Atrophic Gastritis: A Meta-Analysis.

A meta-analysis was performed to assess the diagnostic value of gastrin-17 (G-17) for the early detection of chronic atrophic gastritis (CAG).An extensive literature search was performed, with the aim of selecting publications that reported the accuracy of G-17 in predicting CAG, in the following databases: PubMed, Science Direct, Web of Science, Chinese Biological Medicine, Chinese National Knowledge Infrastructure, Wanfang, and VIP. To assess the diagnostic value of G-17, the following statistics were estimated and described: sensitivity, specificity, diagnostic odds ratios (DOR), summary receiver operating characteristic curves, area under the curve (AUC), and 95% confidence intervals (CIs).Thirteen studies that met the inclusion criteria were included in this meta-analysis, comprising 894 patients and 1950 controls. The pooled sensitivity and specificity of these studies were 0.48 (95% CI: 0.45-0.51) and 0.79 (95% CI: 0.77-0.81), respectively. The DOR was 5.93 (95% CI: 2.93-11.99), and the AUC was 0.82.G-17 may have potential diagnostic value because it has good specificity and a moderate DOR and AUC for CAG. However, more studies are needed to improve the sensitivity of this diagnostic tool in the future.

Palladium-Catalyzed Formal Insertion of Carbenoids into Aminals via C-N Bond Activation.

A new strategy for selective insertion of metal carbenes into C-N bond has been developed via Pd-catalyzed C-N bond activation. A series of aminals and α-diazoesters with different substituents were successfully incorporated even in 0.1 mol % of catalyst under mild conditions, affording a wide range of α,ß-diamino acid esters with quarternary carbon-centers. Preliminary mechanistic studies uncovered that the unique electrophilic cyclopalladated species could easily react with diazoacetates to generate a Pd-carbenoid intermediate which was involved in the catalytic cycle.

[Levels of polychlorinated biphenyls in Tibetan and Yi adolescents' hair from Liangshan Prefecture, Sichuan Province].

Adolescents' (11-19 years old) hair samples (n =39) collected from Liangshan prefecture, Sichuan Province were analyzed for 12 dioxin-like polychlorinated biphenyl(DL-PCBs) congeners by gas chromatography-mass spectrometry(GC-MS). The levels and distribution characteristics of DL-PCBs in Tibetan and Yi Adolescents' hair were studied, meanwhile, the relationships between the levels of DL-PCBs and the nationalities, eating habits and genders were addressed. The results indicated that the average concentration of PCBs was (102.2 +/- 14. 3) pg x g(-1) with the range from 9.6 pg x g(-1) to 991.6 pg x g(-1). The concentration levels of this region were relatively low. PCB-77, PCB-105 and PCB-118 were the major congeners, contributing to 84.7% of the total. The levels of PCBs in Yi teenagers' hair were higher than those in Tibetan, and the concentration in hair was related to the frequency of eating meats and drinking milk per week. It might be attributed to the different eating habits of these two nationalities. When gender was considered, significantly higher concentrations were found in female than in male (P < 0.05).

Generation, transmission and infectiosity of chicken MDV aerosols under experimental conditions.

To further investigate the airborne infection mechanism of Marek's disease virus (MDV), a MDV aerosol infection model was established, and the generation, transmission and infectiosity of MDV aerosols were monitored in this study. Two positive/negative pressure isolators, in which SPF chickens were raised, were connected with a closed conduit. Two repetitive trials, Trial 1 (T1) and Trial 2 (T2) were carried out for objective assessment. Air samples were collected using the AGI-30 sampler. Viral DNA in air samples and feather follicle samples were detected using real-time quantitative PCR (QRT-PCR). MDV in air and blood samples was detected by indirect immunofluorescence assay (IFA). In chickens of isolator A (MDV inoculation group), MDV was detected in feather follicles in 100% of the tested chickens at 6 days post inoculation (dpi) in both trials; and MDV was isolated from blood samples at 9-10 dpi. MDV DNA was detected in air samples from isolator A at 12 dpi in T1 and 14 dpi in T2 and concentration of aerosolized MDV DNA was peaked at 3.84 × 10(6)copies/m(3) air at 40 dpi in T1, and 6.17 × 10(5)copies/m(3) air at 38 dpi in T2, respectively. Infectious MDV (cell culture) was isolated from isolator A at 17 in T1 and 19 dpi in T2, respectively. MDV aerosol in Isolator B was almost same as isolator A. Viremia was detected in isolator B at 26-30 dpi. The incidence of viremia in isolator B reached 70% at 3 months post inoculation. These results demonstrated that infected chicken could discharge virus, the MDV could form aerosols and infect neighboring chickens. Understanding the mechanism of generation and infection of MDV aerosols is helpful to prevent and control MD.

Rh-catalyzed oxidative C-H activation/annulation: converting anilines to indoles using molecular oxygen as the sole oxidant.

A practical and efficient Rh(III)-catalyzed aerobic C-H activation has been developed for the facile synthesis of a broad range of indoles from simple anilines and alkynes. The protocol could be conducted under mild conditions and used environmentally friendly oxygen as the sole clear oxidant.