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Find video protocols related to scientific articles indexed in Pubmed.
Trisulfur Radical Anion as the Key Intermediate for the Synthesis of Thiophene via the Interaction between Elemental Sulfur and NaOtBu.
Org. Lett.
PUBLISHED: 11-20-2014
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A facile base-promoted sulfur-centered radical generation mode and a single-step protocol for the synthesis of thiophene derivatives using 1,3-diynes via the interaction between elemental sulfur and NaOtBu has been reported. EPR experiments revealed that the trisulfur radical anion acts as a key intermediate of this process. A plausible mechanism has been proposed.
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Specific Gene Repression by CRISPRi System Transferred through Bacterial Conjugation.
ACS Synth Biol
PUBLISHED: 11-20-2014
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In microbial communities, bacterial populations are commonly controlled using indiscriminate, broad range antibiotics. There are few ways to target specific strains effectively without disrupting the entire microbiome and local environment. Here we use conjugation, a natural DNA horizontal transfer process among bacterial species, to deliver an engineered CRISPR interference (CRISPRi) system for targeting specific genes in recipient Escherichia coli cells. We show that delivery of the CRISPRi system is successful and can specifically repress a reporter gene in recipient cells, thereby establishing a new tool for gene regulation across bacterial cells and potentially for bacterial population control.
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Revealing the halide effect on the kinetics of the aerobic oxidation of Cu(i) to Cu(ii).
Chem. Commun. (Camb.)
PUBLISHED: 11-20-2014
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In situ infrared (IR) and X-ray absorption near-edge structure (XANES) spectroscopic investigations reveal that different halide ligands have distinct effects on the aerobic oxidation of Cu(i) to Cu(ii) in the presence of TMEDA (tetramethylethylenediamine). The iodide ligand gives the lowest rate and thus leads to the lowest catalytic reaction rate of aerobic oxidation of hydroquinone to benzoquinone. Further DFT calculations suggest that oxidation of CuI-TMEDA involves a side-on transition state, while oxidation of CuCl-TMEDA involves an end-on transition state which has a lower activation energy.
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Comparison of the effects of extracellular and intracellular organic matter extracted from Microcystis aeruginosa on ultrafiltration membrane fouling: dynamics and mechanisms.
Environ. Sci. Technol.
PUBLISHED: 11-18-2014
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Algae organic matter (AOM), including intracellular organic matter (IOM) and extracellular organic matter (EOM), are major membrane foulants in the treatment of algae-polluted water. In this study, the effects of EOM and IOM (at dissolved organic concentrations of 8 mg/L) on the fouling of a polyethersulfone ultrafiltration (UF) membrane were investigated using a dead-end down-flow UF unit. Changes in the membrane pore geometry and the interaction energy between the membrane and foulants were analyzed based on the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The data (relative standard deviation within 10%) showed that UF was able to retain 57% and 46% of IOM and EOM respectively, while the corresponding membrane fluxes rapidly reduced to 28% and 33% of their respective initial values after a specific filtration volume of only 3.75 mL/cm2. The fouling model implied that cake formation was the major mechanism. Specifically, IOM foulant had a much greater free energy of cohesion (-59.08 mJ/m2) than EOM foulant (3.2 mJ/m2), leading to the formation of a compacted cake layer on the membrane surface. In contrast, small molecules of hydrophobic EOM tended to be adsorbed into the membrane pores, leading to significant reduction of the pore size and membrane flux. Therefore, the overall fouling rates caused by EOM and IOM were comparable when both of the above mentioned mechanisms were considered.
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Cu(II)/Cu(I)-Synergistic Cooperation to Lead the Alkyne C-H Activation.
J. Am. Chem. Soc.
PUBLISHED: 11-11-2014
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An efficient alkyne C-H activation procedure has been well studied which indicated that a Cu(II)/Cu(I) synergistic co-operation might be involved. In situ Raman spectroscopy was engaged to study kinetic behavior, drawing the conclusion that Cu(II) didn't participate in the rate determining step. IR and X-ray absorption spectroscopy evidence were provided for structural information, indicating that Cu(II) alone couldn't accelerate the reduction procedure by simply coordinating with C-C triple bond to activate the terminal alkynes; meanwhile, X-band EPR spectra and solubility showed that Cu(I) and Cu(II) could affect the complication environment of each other. A distinctive Cu(I)-Cu(II) synergistic cooperation intermediate was proposed for the putative mechanism.
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Amide Groups Switch Selectivity: C-H Trifluoromethylation of ?,?-Unsaturated Amides and Subsequent Asymmetric Transformation.
Org. Lett.
PUBLISHED: 11-10-2014
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The first direct C-H ?-trifluoromethylation of unsubstituted or ?-alkyl-substituted ?,?-unsaturated carbonyl compounds under metal-free conditions was realized with excellent regio- and stereoselectivity as well as a very broad substrate scope. Both olefinic and allylic trifluoromethylation products are accessible with high selectivities by altering the substrate substitutions. The resultant olefinic products, namely (E)-?-trifluoromethyl (CF3) ?,?-unsaturated hydroxamic acid derivatives, served as acceptors in organocatalytic asymmetric Michael addition reactions to give hydroxamic acid derivatives bearing a chiral CF3-substituted stereocenter with high enantioselectivities.
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Construction of N-containing heterocycles via oxidative intramolecular N-H/X-H coupling.
Chem. Commun. (Camb.)
PUBLISHED: 11-07-2014
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The preparation of N-containing heterocycles is always the core of synthetic chemistry. Recently, oxidative coupling between two R-H nucleophiles is gaining more attention due to its atom-economy and step-economy, thus there are numerous reports focusing on the N-heterocycle construction via oxidative coupling. This feature article is going to cover the methodology related to the construction of N-heterocycles through oxidative intramolecular N-H/X-H coupling.
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Recent Advances of Transition-Metal Catalyzed Radical Oxidative Cross-Couplings.
Acc. Chem. Res.
PUBLISHED: 11-04-2014
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Conspectus Oxidative cross-coupling reactions between two nucleophiles are a powerful synthetic strategy to synthesize various kinds of functional molecules. Along with the development of transition-metal-catalyzed oxidative cross-coupling reactions, chemists are applying more and more first-row transition metal salts (Fe, Co, etc.) as catalysts. Since first-row transition metals often can go through multiple chemical valence changes, those oxidative cross-couplings can involve single electron transfer processes. In the meantime, chemists have developed diverse mechanistic hypotheses of these types of reactions. However, none of these hypotheses have led to conclusive reaction pathways until now. From studying both our own work and that of others in this field, we believe that radical oxidative cross-coupling reactions can be classified into four models based on the final bond formations. In this Account, we categorize and summarize these models. In model I, one of the starting nucleophiles initially loses one electron to generate its corresponding radical under oxidative conditions. Then, bond formations between this radical and another nucleophile create a new radical, [Nu(1)-Nu(2)](•), followed by a further radical oxidation step to generate the cross-coupling product. The radical oxidative alkenylation with olefin, radical oxidative arylative-annulation, and radical oxidative amidation are examples of this model. In model II, one of the starting nucleophiles loses its two electrons via two steps of single-electron-transfer to generate an electrophilic intermediate, followed by a direct bond formation with the other nucleophile. For example, the oxidative C-O coupling of benzylic sp(3) C-H bonds with carboxylic acids and oxidative C-N coupling of aldehydes with amides are members of this model group. For model III, both nucleophiles are oxidized to their corresponding radicals. Then, the radicals combine to form the final coupling product. The dioxygen-involved radical oxidative cross-couplings between sulfinic acids and olefins or alkynes belong to this bond formation model. Lastly, in model IV, one nucleophile loses two electrons to generate an electrophilic intermediate, while the other nucleophile loses one electron to generate a radical. Then, a bond forms between the cation and the radical to generate a cationic radical, followed by a one-electron reduction to afford the final coupling product. The oxidative coupling between arylboronic acids and simple ethers was classified in this model. At the current stage, there are only a few examples presented for models III and IV, but they represent two types of potentially important transformations. More and more examples of these two models will be developed in the future.
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Direct Simulation Evidence of Generation of Oxygen Vacancies at the Golden Cage Au16 and TiO2 (110) Interface for CO Oxidation.
J. Am. Chem. Soc.
PUBLISHED: 10-29-2014
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We show Born-Oppenheimer molecular dynamics (BOMD) simulation evidence of the generation of oxygen vacancies at the golden cage Au16 and TiO2 (110) interface for CO oxidation. Unlike the conventional Langmuir-Hinshelwood (L-H) mechanism, the CO molecule adsorbed at the perimeter Au sites of Au16 tends to attack a nearby lattice oxygen atom on the TiO2 (110) surface rather than the neighboring co-adsorbed molecular O2. Our large-scale BOMD simulation provides, to our knowledge, the first real-time demonstration of feasibility of the Mars-van Krevelen (M-vK) mechanism as evidenced by the generation of oxygen vacancies on the TiO2 surface in the course of the CO oxidation. Furthermore, a comparative study of the CO oxidation at the golden cage Au18 and TiO2 interface suggests that the L-H mechanism is more favorable than the M-vK mechanism due to higher structural robustness of the Au18 cage. It appears that the selection of either M-vK or L-H mechanism for the CO oxidation is dependent on the structural fluxionality of the Au cage clusters on the TiO2 support.
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High-power all-fiber wavelength-tunable thulium doped fiber laser at 2 ?m.
Opt Express
PUBLISHED: 10-17-2014
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Power scaling of an all-fiber wavelength-tunable thulium doped fiber laser (TDFL) based on a monolithic master oscillator power amplifier (MOPA) system is presented. The whole configuration is comprised of a low-power seed oscillator and two stages of double-cladding thulium doped fiber amplifiers (TDFAs). The tuning of the operating wavelength is realized by inserting a spectral tunable filter into the seed oscillator. Maximum average output power of 115 W is obtained at 1950 nm with a linearly fitted slope efficiency of 51.7%. This laser has superior spectral characteristics with wavelength tunable from 1940 nm to 2070 nm. To the best of our knowledge, this is the first demonstration of an all-fiber wavelength-tunable TDFL at 2 ?m with output power exceeding 100 W. The results are of great interest for many application areas.
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LRP4 Is Critical for Neuromuscular Junction Maintenance.
J. Neurosci.
PUBLISHED: 10-17-2014
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The neuromuscular junction (NMJ) is a synapse between motor neurons and skeletal muscle fibers, and is critical for control of muscle contraction. Its formation requires neuronal agrin that acts by binding to LRP4 to stimulate MuSK. Mutations have been identified in agrin, MuSK, and LRP4 in patients with congenital myasthenic syndrome, and patients with myasthenia gravis develop antibodies against agrin, LRP4, and MuSK. However, it remains unclear whether the agrin signaling pathway is critical for NMJ maintenance because null mutation of any of the three genes is perinatal lethal. In this study, we generated imKO mice, a mutant strain whose LRP4 gene can be deleted in muscles by doxycycline (Dox) treatment. Ablation of the LRP4 gene in adult muscle enabled studies of its role in NMJ maintenance. We demonstrate that Dox treatment of P30 mice reduced muscle strength and compound muscle action potentials. AChR clusters became fragmented with diminished junctional folds and synaptic vesicles. The amplitude and frequency of miniature endplate potentials were reduced, indicating impaired neuromuscular transmission and providing cellular mechanisms of adult LRP4 deficiency. We showed that LRP4 ablation led to the loss of synaptic agrin and the 90 kDa fragments, which occurred ahead of other prejunctional and postjunctional components, suggesting that LRP4 may regulate the stability of synaptic agrin. These observations demonstrate that LRP4 is essential for maintaining the structural and functional integrity of the NMJ and that loss of muscle LRP4 in adulthood alone is sufficient to cause myasthenic symptoms.
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Evidence of guest encapsulation within G8 and G10 dendrimers using NMR techniques.
Soft Matter
PUBLISHED: 10-16-2014
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Encapsulation of guest molecules within the interior cavities of dendrimers is promising, but high generation dendrimers show limited encapsulation capacity due to their dense surface shell. Here, for the first time, we prove that high generation polyamidoamine dendrimers, such as generation 8 and generation 10, are able to encapsulate hydrophobic guests using NMR spectroscopy. Guest molecules such as phenylbutazone, dexamethasone sodium phosphate and 9-anthracenecarboxylic acid with molecular weights up to 516 Da are in close proximity to the interior scaffold protons of high generation dendrimers. This encapsulation behavior depends on guest hydrophobicity. Chemical defects and back-folding of terminal groups make it possible for these guest molecules to penetrate through the dense surface shell of high generation dendrimers. These results provide new insights into the host-guest chemistry of dendrimers.
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I2-catalyzed oxidative C(sp(3))-H/S-H coupling: utilizing alkanes and mercaptans as the nucleophiles.
Chem. Commun. (Camb.)
PUBLISHED: 10-10-2014
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By using alkanes and mercaptans as the nucleophiles with di-tert-butyl peroxide (DTBP) as the oxidant, I2-catalyzed oxidative C(sp(3))-H/S-H coupling was achieved. This protocol provides a novel process to construct C(sp(3))-S bonds from commercially available hydrocarbons and mercaptans.
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SEC-10 and RAB-10 coordinate basolateral recycling of clathrin-independent cargo through endosomal tubules in Caenorhabditis elegans.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-09-2014
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Despite the increasing number of regulatory proteins identified in clathrin-independent endocytic (CIE) pathways, our understanding of the exact functions of these proteins and the sequential manner in which they function remains limited. In this study, using the Caenorhabditis elegans intestine as a model, we observed a unique structure of interconnected endosomal tubules, which is required for the basolateral recycling of several CIE cargoes including hTAC, GLUT1, and DAF-4. SEC-10 is a subunit of the octameric protein complex exocyst. Depleting SEC-10 and several other exocyst components disrupted the endosomal tubules into various ring-like structures. An epistasis analysis further suggested that SEC-10 operates at the intermediate step between early endosomes and recycling endosomes. The endosomal tubules were also sensitive to inactivation of the Rab GTPase RAB-10 and disruption of microtubules. Taken together, our data suggest that SEC-10 coordinates with RAB-10 and microtubules to form the endosomal tubular network for efficient recycling of particular CIE cargoes.
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Controllable synthesis of Ni/SiO2 hollow spheres and their excellent catalytic performance in 4-nitrophenol reduction.
Dalton Trans
PUBLISHED: 10-09-2014
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The high cost of noble metal nanoparticles used for catalytic reduction of 4-nitrophenol (4-NP) leads to an extensive study of Ni nanoparticles (NPs) for their low cost and magnetic properties. However, the conventional routes for preparing the ferromagnetic Ni NPs usually lead to large particle size and aggregation. In this study, we propose a simple two-step method for the synthesis of hierarchical Ni NP supported silica magnetic hollow microspheres (Ni/SiO2 MHMs). Tiny Ni NPs are well dispersed on the supports with high loading amounts (15 wt%). The size of Ni NPs can be tuned from 10 nm to 21 nm with the size of Ni/SiO2 MHMs increasing from 230 nm to 800 nm. The as-prepared samples exhibit excellent catalytic activity in the reduction of 4-NP. Furthermore, the experimental results prove that the size of Ni NPs plays an important role in the catalytic activity. The catalytic activity of small sized Ni NPs is higher than that of large sized and many other supported Ni NP catalysts as reported. In particular, the magnetic properties of Ni/SiO2 MHMs make them easy to recycle for reuse.
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Plasminogen kringle 5 induces endothelial cell apoptosis by triggering a voltage-dependent anion channel 1 (VDAC1) positive feedback loop.
J. Biol. Chem.
PUBLISHED: 10-08-2014
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Human plasminogen kringle 5 (K5) is known to display its potent anti-angiogenesis effect through inducing endothelial cell (EC) apoptosis, and the voltage-dependent anion channel 1 (VDAC1) has been identified as a receptor of K5. However, the exact role and underlying mechanisms of VDAC1 in K5-induced EC apoptosis remain elusive. In the current study, we showed that K5 increased the protein level of VDAC1, which initiated the mitochondrial apoptosis pathway of ECs. Our findings also showed that K5 inhibited the ubiquitin-dependent degradation of VDAC1 by promoting the phosphorylation of VDAC1, possibly at Ser12 and Thr107. The phosphorylated VDAC1 was attenuated by AKT agonist, GSK3? inhibitor and siRNA?suggesting that K5 increased VDAC1 phosphorylation via the AKT-GSK3? pathway. Furthermore, K5 promoted cell surface translocation of VDAC1, and binding between K5 and VDAC1 was observed on the plasma membrane. HKI protein blocked the impact of K5 on the AKT-GSK3? pathway by competitively inhibiting the interaction of K5 and cell surface VDAC1. Moreover, K5-induced EC apoptosis was suppressed by VDAC1 antibody. These data show for the first time that K5-induced EC apoptosis is mediated by the positive feedback loop of "VDAC1-AKT-GSK3?-VDAC1", which may provide new perspectives on the mechanisms of K5-induced apoptosis.
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Relay cooperation of K2S2O8 and O2 in oxytrifluoromethylation of alkenes using CF3SO2Na.
Chem. Commun. (Camb.)
PUBLISHED: 10-04-2014
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A new radical oxytrifluoromethylation of alkenes via an aerobic Cvinyl-heteroatom bond oxygenation process is reported, in which O2 and a catalytic amount of K2S2O8 work in concert to activate CF3SO2Na. Mechanistic investigation disclosed that CF3SO2? could react with O2 to reinitiate radical chain process.
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A TAK1 Signaling Pathway Critically Regulates Myocardial Survival and Remodeling.
Circulation
PUBLISHED: 10-04-2014
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-Programmed necrosis (necroptosis) plays an important role in development, tissue homeostasis, and disease pathogenesis. The molecular mechanisms that regulate necroptosis in the heart and its physiological relevance in myocardial remodeling and heart failure remain largely unknown.
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A preliminary study on the role of the complement regulatory protein, cluster of differentiation 55, in mice with diabetic neuropathic pain.
Mol Med Rep
PUBLISHED: 10-03-2014
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The aim of this study was to investigate the role of the complement regulatory protein cluster of differentiation 55 (CD55) in the pathogenesis of diabetic neuropathic pain (DNP). Healthy adult male C57BL/6J mice were intraperitoneally injected with streptozotocin (STZ) in order to induce DNP. Peripheral blood glucose and protein, and the mRNA expression levels of C3 and CD55 in the spinal cord were determined. In addition, the behaviors of these mice were observed. The results showed that STZ?treated mice displayed the clinical manifestations of diabetes mellitus, and that their peripheral blood glucose was markedly increased. On the 21st and 28th days following the STZ injection, the mechanical pain threshold and thermal pain threshold of the mice were dramatically reduced (P<0.05). |Additionally, 14 days post?STZ injection, the mRNA expression of C3 in the spinal cord was significantly increased, which continued for 28 days. On the 21st and 28th days, the number of C3 positive cells in the spinal cord was markedly increased. Seven days after the STZ injection, the number of cells positive for CD55 was markedly reduced in the spinal dorsal horn and subsequently remained at a low level. The mRNA expression of CD55 also was significantly reduced (P<0.05) and remained so for 28 days. The reduction in the expression levels of CD55 occurred earlier than the changes in the expression of C3, suggesting that the downregulation of CD55 expression precedes, and has an important role regarding, the activation of C3 in the occurrence and development of DNP.
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Screening aberrant methylation profile in esophageal squamous cell carcinoma for Kazakhs in Xinjiang area of China.
Mol. Biol. Rep.
PUBLISHED: 09-30-2014
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To screen the aberrant methylation genes in esophageal squamous cell carcinoma (ESCC) for Kazakh nationality in Xinjiang, and the aberrant DNA methylation genes pattern provides a clue for deeply study on ESCC mechanism. Illumina Human Methylation 450 K chip was used to screen the genome-wide methylation on six cancer tissues and six adjacent normal tissues of ESCC in Kazakh people. Meanwhile, mRNA library was constructed by scanning the RNA expression on two cancer tissues and two adjacent normal tissues by Hiseq2000. After association study between the methylation profile and expression profile, aberrant DNA methylated genes were screened out and were uploaded to the GoMiner and the KEGG, completing the bioinformatic analysis. There were 227 hypermethylation genes and 6 hypomethylated genes in cancer tissue, mRNA expression varied from 0.0312 to 8,192 in cancer tissues compared with 0.0312-1,024 in adjacent normal tissues. The correlation study indicated that there were 10 loci in 10 down-regulated genes of hypermethylated in negative correlation group. Additionally, there were 11 loci in 10 up-regulated genes in negative group. Using GoMiner to do GO analysis on aberrant DNA methylation genes, RAPGEFL1, TP53AIP1, KIAA1522, DUOXA2 were identified not involved in any biological processes. ALDH1L1 participated in folinic acid catabolism and CAPN1 positively regulated the cell proliferation. And ALDH1L1 involved in one carbon metabolism and CAPN1 participate in the apoptosis process by applying pathway analysis. The aberrant DNA methylation profiles were established and provided a clue for deeply study on ESCC of Kazakh nationality.
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An unexpected deamination reaction after hydrolysis of the pyrimidine (6-4) pyrimidone photoproduct.
Org. Lett.
PUBLISHED: 09-24-2014
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Pyrimidine (6-4) pyrimidone photoproduct (6-4PP), a common DNA photolesion formed under solar irradiation, was indicated to hydrolyze under strong basic conditions, breaking the N3-C4 bond at the 5'-thymine. The reanalysis of this reaction revealed that the resulting water adduct may not be stable as previously proposed; it readily undergoes an esterification reaction induced by the 5-OH group at 6-4PP to form a five-membered ring, eliminating a molecule of ammonia.
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[Distribution, seasonal variation and influence factors of dissolved inorganic arsenic in the Sanggou Bay].
Huan Jing Ke Xue
PUBLISHED: 09-24-2014
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The biogeochemical behavior of arsenic in the aquatic environment has already captured the attentions of scientists due to its complex forms and toxicity. Four cruises were carried out in April, August, October 2011 and January 2012 in the Sanggou Bay. The concentrations of total dissolved inorganic arsenic (TDIAs, TDIAs = [ As(5+] + [As(3+)]) and arsenite (As(3+)) were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS). The concentrations of TDIAs ranged from 3.4-12.4 nmol x L(-1) in April, 8.9-16.9 nmol x L(-1) in August, 14.7-21.3 nmol x L(-1) in October and 13.8-21.9 nmol x L(-1) in January. The concentrations of arsenite ranged from 0.3-2.1 nmol x L(-1), 0.4-3.8 nmol x L(-1), 1.8-4.0 nmol x L(-1) and 0.3-2.9 nmol x L(-1) during four cruises, respectively. The concentrations of TDIAs in spring and summer were lower than those in autumn and winter, and high values of TDIAs appeared in the bay-mouth and the coastal estuary. The concentrations of arsenite in spring and winter were lower than those in summer and autumn. The maximum As(3+)/TDIAs ratios appeared in summer. The mean value of TDIAs in the Sanggou Bay was (13.9 +/- 4.7) nmol x L(-1), which was lower than the national primary drinking in water Standards from USEPA and met the first grade water quality based on the environmental quality standards for surface water of China. It indicates that there is no obvious anthropogenic pollution. The concentrations of TDIAs in the Sanggou Bay were lower than those in the Ailian Bay and the Lidao Bay in spring and summer due to the different hydrological environments and terrestrial inputs. Riverine input, incursion of Yellow Sea and biological activities were the three main factors impacting the distribution of TDIAs in the Sanggou Bay, and the influence of aquaculture activities was particularly significant. The enrichment of arsenic by aquaculture may lead to potential ecological crisis and food safety problems, and need to be paid more attentions to ensure the sustainable development of aquaculture in the Sanggou Bay.
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[Intervention effect of quercetin on inflammatory secretion of cardiac fibroblasts].
Zhongguo Zhong Yao Za Zhi
PUBLISHED: 09-24-2014
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To establish neonatal rat cardiac fibroblast inflammatory secretion model by using LPS 100 microg x L(-1) combined with ATP 5 mmol x L(-1), in order to study the inhibitory effect of quercetin on the secretion of inflammatory factors TNF-alpha, IL-1beta and IL-6 of cardiac fibroblasts, further investigate the effect of quercetin on the protein expression of p-NF-kappaB p65 (S276) and p-Akt (S473) by western blot, and discuss the inhibitory effect of quercetin on the inflammatory secretion of cardiac fibroblasts. According to the findings, quercetin with the concentrations between 51.74 micromol x L(-1) and 827.81 micromol x L(-1) had no significant effect on the activity of cardiac fibroblasts. Quercetin with the concentrations of 82.78, 41.39, 20.70 micromol x L(-1) could notably inhibit the increase of TNF-alpha and IL-1beta induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 36 h (P < 0.01 or P < 0.05). Quercetin with the concentrations of 82.78, 41.39 micromol x L(-1) could notably inhibit the increase of IL-6 induced LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 36 h (P < 0.05), without any notable effect of quercetin with the concentration of 20.70 micromol x L(-1). Quercetin with the concentrations of 82.78, 41.39, 20. 70 micromol x L(-1) could notably inhibit the NF-kappaB p65 (S276) activation induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 15 min, with the most significant effect in 20.70 micromol x L(-1). Quercetin with the concentrations of 82.78, 41.39, 20.70 micromol x L(-1) could notably inhibit the increase of p-Akt(473) expression induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 240 min (P < 0.05). Therefore, this study believes that quercetin could attenuate the secretion of inflammatory factors TNF-alpha, IL-1beta and IL-6 of cardiac fibroblasts by inhibiting the activation of NF-kappaB p65 (S276) and Akt (473).
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Synergistic Activity of Econazole-Nitrate and Chelerythrine against Clinical Isolates of Candida albicans.
Iran J Pharm Res
PUBLISHED: 09-20-2014
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The aim of this investigation was to assess the in-vitro interaction of two antifungal agents, econazole-nitrate and chelerythrine, against ten fluconazole-resistant clinical isolates and one ATCC type strain 10231 of Candida albicans. The checkerboard microdilution method was performed according to the recommendations of the National Committee for Clinical Laboratory Standards, and the results were determined by visual examination. The interaction intensity was tested in all isolates using the fractional inhibitory concentration index (FICI). These experiments showed synergism between econazole-nitrate and chelerythrine in antifungal activity against C. albicans, and no antagonistic activity was observed in any of the strains tested. Moreover, time-kill curves were performed with selected strains to confirm the positive interactions. The similarity between the results of the FICI values and the time-kill curves revealed that chelerythrine greatly enhances the antifungal effects of econazole-nitrate against isolates of C. albicans. This synergistic effect may markedly reduce the dose of econazole-nitrate required to treat candidiasis, thereby decreasing the econazole-nitrate toxic side effects. This novel synergism might provide a potential combination treatment against fungal infections.
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Copper-Catalyzed Radical Carbooxygenation: Alkylation and Alkoxylation of Styrenes.
Chem Asian J
PUBLISHED: 09-19-2014
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A simple copper-catalyzed direct radical carbooxygenation of styrenes is developed utilizing alkyl bromides as radical resources. This catalytic radical difunctionalization accomplishes both alkylation and alkoxylation of styrenes in one pot. A broad range of styrenes and alcohols are well tolerated in this transformation. The EPR experiment shows that alkyl halides could oxidize Cu(I) to Cu(II) in this transformation.
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Comparison of pre-operation diagnosis of thyroid cancer with fine needle aspiration and core-needle biopsy: a meta-analysis.
Asian Pac. J. Cancer Prev.
PUBLISHED: 09-18-2014
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The aim of this meta-analysis was to compare sensitivities and specificities of fine needle aspiration (FNA) and core needle biopsy (CNB) in the diagnosis of thyroid cancer.
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Pigment Epithelial-derived Factor (PEDF)-triggered Lung Cancer Cell Apoptosis Relies on p53 Protein-driven Fas Ligand (Fas-L) Up-regulation and Fas Protein Cell Surface Translocation.
J. Biol. Chem.
PUBLISHED: 09-15-2014
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Pigment epithelium-derived factor (PEDF), a potent antiangiogenesis agent, has recently attracted attention for targeting tumor cells in several types of tumors. However, less is known about the apoptosis-inducing effect of PEDF on human lung cancer cells and the underlying molecular events. Here we report that PEDF has a growth-suppressive and proapoptotic effect on lung cancer xenografts. Accordingly, in vitro, PEDF apparently induced apoptosis in A549 and Calu-3 cells, predominantly via the Fas-L/Fas death signaling pathway. Interestingly, A549 and Calu-3 cells are insensitive to the Fas-L/Fas apoptosis pathway because of the low level of cell surface Fas. Our results revealed that, in addition to the enhancement of Fas-L expression, PEDF increased the sensitivity of A549 and Calu-3 cells to Fas-L-mediated apoptosis by triggering the translocation of Fas protein to the plasma membrane in a p53- and FAP-1-dependent manner. Similarly, the up-regulation of Fas-L by PEDF was also mediated by p53. Furthermore, peroxisome proliferator-activated receptor ? was determined to be the upstream regulator of p53. Together, these findings uncover a novel mechanism of tumor cell apoptosis induced by PEDF and provide a potential therapeutic strategy for tumors that are insensitive to Fas-L/Fas-dependent apoptosis because of a low level of cell surface Fas.
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Efficient synthesis of 1,2,3-triazoles by copper-mediated c?n and n?n bond formation starting from N-tosylhydrazones and amines.
Chemistry
PUBLISHED: 09-03-2014
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An effective copper-mediated synthesis of 1,5-dialkyl-4-aryl-1,2,3-triazoles and 1,4-dialkyl-5-aryl-1,2,3-triazoles has been achieved by the use of different N-tosylhydrazones and alkyl amines. The scope of the substrates could be extended from anilines to aliphatic amines when 30?mol?% amino acid is added into the reaction mixture. This methodology exhibits many notable features, such as broad substrates scope, high efficiency, and good regioselectivity. Preliminary mechanistic studies indicated that the reaction probably proceeded through a 1-tosyl-2-vinyldiazene intermediate and subsequent aza-Michael addition and N?N bond formation process.
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Polysiloxane-based luminescent elastomers prepared by thiol-ene "click" chemistry.
Chemistry
PUBLISHED: 08-28-2014
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Side-chain vinyl poly(dimethylsiloxane) has been modified with mercaptopropionic acid, methyl 3-mercaptopropionate, and mercaptosuccinic acid. Coordinative bonding of Eu(III) to the functionalized polysiloxanes was then carried out and crosslinked silicone elastomers were prepared by thiol-ene curing reactions of these composites. All these europium complexes could be cast to form transparent, uniform, thin elastomers with good flexibility and thermal stability. The networks were characterized by FTIR, NMR, UV/Vis, and luminescence spectroscopy as well as by scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The europium elastomer luminophores exhibited intense red light at 617?nm under UV excitation at room temperature due to the (5)D0 ?(7)F2 transition in Eu(III) ions. The newly synthesized luminescent materials offer many advantages, including the desired mechanical flexibility. They cannot be dissolved or fused, and so they have potential for use in optical and electronic applications.
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Validation of bmi1 as a therapeutic target of hepatocellular carcinoma in mice.
Int J Mol Sci
PUBLISHED: 08-23-2014
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Bmi1 is a member of the polycomb group family of proteins, and it drives the carcinogenesis of various cancers and governs the self-renewal of multiple types of stem cells. Our previous studies have revealed that Bmi1 acts as an oncogene in hepatic carcinogenesis in an INK4a/ARF locus independent manner. However, whether Bmi1 can be used as a potential target for hepatocellular carcinoma treatment has not been fully confirmed yet. Here, we show that perturbation of Bmi1 expression by using short hairpin RNA can inhibit the tumorigenicity and tumor growth of hepatocellular carcinoma cells both in vitro and in vivo. Importantly, Bmi1 knockdown can block the tumor growth, both in the initiating stages and the fast growing stages. Cellular biology analysis revealed that Bmi1 knockdown induces cell cycle arrest and apoptosis. Our findings verify Bmi1 as a qualified treatment target for hepatocellular carcinoma (HCC) and support Bmi1 targeting treatment with chemotherapeutic agents.
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Pigment epithelium-derived factor (PEDF) inhibits breast cancer metastasis by down-regulating fibronectin.
Breast Cancer Res. Treat.
PUBLISHED: 08-19-2014
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Pigment epithelium-derived factor (PEDF) plays an important role in the tumor growth and metastasis inhibition. It has been reported that PEDF expression is significantly reduced in breast cancer, and associated with disease progression and poor patient outcome. However, the exact mechanism of PEDF on breast cancer metastasis including liver and lung metastasis remains unclear. The present study aims to reveal the impact of PEDF on breast cancer. The orthotopic tumor mice model inoculated by MDA-MB-231 cells stably expressing PEDF or control cells was used to assess liver and lung metastasis of breast cancer. In vitro, migration and invasion experiments were used to detect the metastatic abilities of MDA-MB-231 and SKBR3 breast cancer cells with or without overexpression of PEDF. The metastatic-related molecules including EMT makers, fibronectin, and p-AKT and p-ERK were detected by qRT-PCR, Western blot, and Fluorescent immunocytochemistry. PEDF significantly inhibited breast cancer growth and metastasis in vivo and in vitro. Mechanically, PEDF inhibited breast cancer cell migration and invasion by down-regulating fibronectin and subsequent MMP2/MMP9 reduction via p-ERK and p-AKT signaling pathways. However, PEDF had no effect on EMT conversion in the breast cancer cells which was usually involved in cancer metastasis. Furthermore, the study showed that laminin receptor mediated the down-regulation of fibronectin by PEDF. These results reported for the first time that PEDF inhibited breast cancer metastasis by down-regulating fibronectin via laminin receptor/AKT/ERK pathway. Our findings demonstrated PEDF as a dual effector in limiting breast cancer growth and metastasis and highlighted a new avenue to block breast cancer progression.
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Modeling apple surface temperature dynamics based on weather data.
Sensors (Basel)
PUBLISHED: 08-13-2014
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The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management.
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Lutetium-methanediide-alkyl complexes: synthesis and chemistry.
Chemistry
PUBLISHED: 08-11-2014
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The first four-coordinate methanediide/alkyl lutetium complex (BODDI)Lu2 (CH2 SiMe3 )2 (?2 -CHSiMe3 )(THF)2 (BODDI=ArNC(Me)CHCOCHC(Me)NAr, Ar=2,6-iPr2 C6 H3 ) (1) was synthesized by a thermolysis methodology through ?-H abstraction from a Lu-CH2 SiMe3 group. Complex 1 reacted with equimolar 2,6-iPrC6 H3 NH2 and Ph2 C?O to give the corresponding lutetium bridging imido and oxo complexes (BODDI)Lu2 (CH2 SiMe3 )2 (?2 -N-2,6-iPr2 C6 H3 )(THF)2 (2) and (BODDI)Lu2 (CH2 SiMe3 )2 (?2 -O)(THF)2 (3). Treatment of 3 with Ph2 C?O (4?equiv) caused a rare insertion of Lu-?2 -O bond into the C?O group to afford a diphenylmethyl diolate complex 4. Reaction of 1 with PhN=C?O (2?equiv) led to the migration of SiMe3 to the amido nitrogen atom to give complex (BODDI)Lu2 (CH2 SiMe3 )2 -?-{PhNC(O)CHC(O)NPh(SiMe3 )-?(3) N,O,O}(THF) (5). Reaction of 1 with tBuN?C formed an unprecedented product (BODDI)Lu2 (CH2 SiMe3 ){?2 -[?(2) :?(2) -tBuNC(=CH2 )SiMe2 CHC?NtBu-?(1) N]}(tBuN?C)2 (6) through a cascade reaction of N?C bond insertion, sequential cyclometalative ?-(sp(3) )-H activation, C?C bond formation, and rearrangement of the newly formed carbene intermediate. The possible mechanistic pathways between 1, PhN?C?O, and tBuN?C were elucidated by DFT calculations.
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A Review of Imaging Techniques for Plant Phenotyping.
Sensors (Basel)
PUBLISHED: 08-08-2014
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Given the rapid development of plant genomic technologies, a lack of access to plant phenotyping capabilities limits our ability to dissect the genetics of quantitative traits. Effective, high-throughput phenotyping platforms have recently been developed to solve this problem. In high-throughput phenotyping platforms, a variety of imaging methodologies are being used to collect data for quantitative studies of complex traits related to the growth, yield and adaptation to biotic or abiotic stress (disease, insects, drought and salinity). These imaging techniques include visible imaging (machine vision), imaging spectroscopy (multispectral and hyperspectral remote sensing), thermal infrared imaging, fluorescence imaging, 3D imaging and tomographic imaging (MRT, PET and CT). This paper presents a brief review on these imaging techniques and their applications in plant phenotyping. The features used to apply these imaging techniques to plant phenotyping are described and discussed in this review.
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Copper-catalysed direct radical alkenylation of alkyl bromides.
Org. Biomol. Chem.
PUBLISHED: 07-29-2014
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A copper-catalysed direct radical alkenylation of various benzyl bromides and ?-carbonyl alkyl bromides has been developed. Compared with the recent radical alkenylations which mostly focused on secondary or tertiary alkyl halides, this transformation shows good reactivity to primary alkyl halides and tertiary, secondary alkyl halides were also tolerated. The key initiation step of this transformation is a copper-induced single-electron reduction of C-Br bonds to generate alkyl radical species.
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Carbon-centered radical addition to o?c of amides or esters as a route to c?o bond formations.
Chemistry
PUBLISHED: 07-27-2014
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Among various types of radical reactions, the addition of carbon radicals to unsaturated bonds is a powerful tool for constructing new chemical bonds, in which the typical applied unsaturated substrates include alkenes, alkynes and imines. Carbonyl is perhaps the most common unsaturated group in nature. This work demonstrates a novel C?O bond formation through carbon-centered radical addition to the carbonyl oxygen of amide or ester, in which amide and ester groups are easily activated through the radical process. EPR spectroscopy and radical clock experiments support the radical process for this transformation, and density functional theory (DFT) calculations support the possibility of carbon-centered radical addition to the carbonyl oxygen of amides or esters.
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Direct oxidative esterification of alcohols.
Dalton Trans
PUBLISHED: 07-25-2014
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Esterification is a fundamental transformation in chemistry. Traditional esterification only largely occurs between carboxylic acid derivatives and alcohols, and often involves multistep processes. Developments in the transition-metal-catalysed and metal-free direct esterification of alcohols under oxidative conditions has opened a door to the efficient, sustainable and environmentally friendly synthesis of esters from readily available materials. This Perspective gives an overview which covers the recent development of this emerging field.
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Genome-Scale CRISPR-Mediated Control of Gene Repression and Activation.
Cell
PUBLISHED: 07-15-2014
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While the catalog of mammalian transcripts and their expression levels in different cell types and disease states is rapidly expanding, our understanding of transcript function lags behind. We present a robust technology enabling systematic investigation of the cellular consequences of repressing or inducing individual transcripts. We identify rules for specific targeting of transcriptional repressors (CRISPRi), typically achieving 90%-99% knockdown with minimal off-target effects, and activators (CRISPRa) to endogenous genes via endonuclease-deficient Cas9. Together they enable modulation of gene expression over a ?1,000-fold range. Using these rules, we construct genome-scale CRISPRi and CRISPRa libraries, each of which we validate with two pooled screens. Growth-based screens identify essential genes, tumor suppressors, and regulators of differentiation. Screens for sensitivity to a cholera-diphtheria toxin provide broad insights into the mechanisms of pathogen entry, retrotranslocation and toxicity. Our results establish CRISPRi and CRISPRa as powerful tools that provide rich and complementary information for mapping complex pathways.
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Directional photomanipulation of breath figure arrays.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 07-15-2014
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Porous polymeric films are of paramount importance in many areas of modern science and technology. However, processing methods typically based on direct writing, imprint, and lithography techniques have low throughput and are often limited to specific fabricated shapes. Herein, we demonstrate the directional photomanipulation of breath figure arrays (BFAs) formed by an azobenzene-containing block copolymer to address the aforementioned problems. Under the irradiation of linearly polarized light, the round pores in the BFAs were converted to rectangular, rhombic, and parallelogram-shaped pores in 30?min, due to the anisotropic mass migration based on the photo-reconfiguration of the azobenzene units. Through a secondary irradiation after rotating the sample by 90°, the transformed pores were apparently recovered. Therefore, this non-contacted, directional photomanipulation technique in conjunction with breath figure processing opens a new route to nano/microporous films with finely tuned features.
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Bone marrow mesenchymal stem cells repair spinal cord ischemia/reperfusion injury by promoting axonal growth and anti-autophagy.
Neural Regen Res
PUBLISHED: 07-14-2014
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Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after transplantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are known to protect against spinal cord ischemia/reperfusion injury through anti-apoptotic effects, the precise mechanisms remain unclear. In the present study, bone marrow mesenchymal stem cells were cultured and proliferated, then transplanted into rats with ischemia/reperfusion injury via retro-orbital injection. Immunohistochemistry and immunofluorescence with subsequent quantification revealed that the expression of the axonal regeneration marker, growth associated protein-43, and the neuronal marker, microtubule-associated protein 2, significantly increased in rats with bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Furthermore, the expression of the autophagy marker, microtubule-associated protein light chain 3B, and Beclin 1, was significantly reduced in rats with the bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Western blot analysis showed that the expression of growth associated protein-43 and neurofilament-H increased but light chain 3B and Beclin 1 decreased in rats with the bone marrow mesenchymal stem cell transplantation. Our results therefore suggest that bone marrow mesenchymal stem cell transplantation promotes neurite growth and regeneration and prevents autophagy. These responses may likely be mechanisms underlying the protective effect of bone marrow mesenchymal stem cells against spinal cord ischemia/reperfusion injury.
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Enhanced expression of SAM-pointed domain-containing Ets-like factor in Chronic rhinosinusitis with nasal polyps.
Laryngoscope
PUBLISHED: 07-11-2014
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Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by significant goblet hyperplasia and mucus hypersecretion. However, the molecular mechanism underlying mucin overexpression in CRSwNP has not been well characterized. This study sought to assess the expression of SAM-pointed domain-containing Ets-like factor (SPDEF) and its regulation of mucin production in CRSwNP patients.
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Two Years versus One Year of Tianjiu Therapy in Sanfu Days for Chronic Asthma: A Clinical Efficacy Observation Trial.
Evid Based Complement Alternat Med
PUBLISHED: 07-05-2014
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Background. Tianjiu therapy has established efficacy against chronic asthma with related symptoms or the medication need during asthma attack. This study aimed to explore the optimal duration of Tianjiu therapy for asthma. Methods. This study was a self-comparison-to-the-baseline study, which comparing treatment with Tianjiu therapy for 1 year and 2 years in the same 102 chronic asthma patients. Totally 6 sessions of Tianjiu treatment were provided, 3 sessions in a year as a course of treatment and totally two years treatment. The primary endpoint was the number of asthma related symptoms which frequently appeared in asthma patients and the frequency of bronchodilator used during asthma attack. Results. The frequency of bronchodilator used during asthma attack significantly improved (? (2) = 46.276, P = 0.000). But the number of asthma related symptoms which frequently appeared in asthma patients added by 1.38 points (95% CI, 0.25 to 2.51), 2.93 ± 0.41 in 1-year group and 4.31 ± 0.41 in the 2-years group (P < 0.05). Conclusions. The effect of 2 years Tianjiu therapy was not as effective as 1 year such treatment for asthma, but the second year Tianjiu therapy was still needed because it has a role to consolidate the curative effect of Tianjiu therapy for asthma.
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Synergistic Pd/enamine catalysis: a strategy for the C-H/C-H oxidative coupling of allylarenes with unactivated ketones.
Org. Lett.
PUBLISHED: 06-25-2014
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By combining catalytic nucleophilic enamine activation with Pd-catalyzed C-H activation of allylarenes, the first oxidative allylic alkylation of unactivated ketones was achieved. Mechanistically, the Pd-catalyzed allylic C-H activation and proline-catalyzed ketone nucleophilic activation worked synergistically for the oxidative cross-coupling between allylarenes and unactivated ketones.
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Structure-kinetic relationship study of organozinc reagents.
Chem. Commun. (Camb.)
PUBLISHED: 06-25-2014
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Phenylzinc reagents prepared from various zinc halides show distinct kinetic features in the palladium-catalyzed Negishi-type oxidative coupling reaction, in which the phenylzinc reagent prepared from ZnI2 gives the highest rate. In situ infrared and X-ray absorption spectroscopy studies show that the higher reaction rate was observed for longer Zn-C bond distances.
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Production and characterization of high efficiency bioflocculant isolated from Klebsiella sp. ZZ-3.
Bioresour. Technol.
PUBLISHED: 06-23-2014
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In this study, a new bioflocculant (ZZ-3) is isolated and evaluated. This novel flocculant was derived Klebsiella, which was identified by 16S rDNA sequencing as well as biochemical and physiological analyses. The composition of ZZ-3 was found to be 84.6% polysaccharides and 6.1% protein. More specifically, the amount (moles) of the polysaccharides rhamnose, mannose, and galactose were found to be 6.48, 2.47, and 1.74 greater than glucose, respectively. Results show ZZ-3 has a relatively high molecular weight (603-1820 kDa) and contains many functional groups (hydroxyl, amide, carboxyl, and methoxyl) that likely contribute to flocculation. The results of microscopic observation, zeta potential measurements, and ZZ-3 bioflocculant structure suggested that bridging was the main mechanism for flocculation with kaolin. Based on a high flocculation efficiency, thermal stability, pH tolerance and the ability to flocculate without additional cations, ZZ-3 shows potential for industrial application.
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Early warning indicators for monitoring the process failure of anaerobic digestion system of food waste.
Bioresour. Technol.
PUBLISHED: 06-16-2014
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To determine reliable state parameters which could be used as early warning indicators of process failure due to the acidification of anaerobic digestion of food waste, three mesophilic anaerobic digesters of food waste with different operation conditions were investigated. Such parameters as gas production, methane content, pH, concentrations of volatile fatty acid (VFA), alkalinity and their combined indicators were evaluated. Results revealed that operation conditions significantly affect the responses of parameters and thus the optimal early warning indicators of each reactor differ from each other. None of the single indicators was universally valid for all the systems. The universally valid indicators should combine several parameters to supply complementary information. A combination of total VFA, the ratio of VFA to total alkalinity (VFA/TA) and the ratio of bicarbonate alkalinity to total alkalinity (BA/TA) can reflect the metabolism of the digesting system and realize rapid and effective early warning.
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Transition-metal-assisted radical/radical cross-coupling: a new strategy to the oxidative C(sp3)-H/N-H cross-coupling.
Org. Lett.
PUBLISHED: 06-12-2014
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A transition-metal-assisted oxidative C(sp(3))-H/N-H cross-coupling reaction of N-alkoxyamides with aliphatic hydrocarbons is described. During the reaction, nitrogen radicals were generated from the oxidation of N-alkoxyamides. Experiments and DFT calculations revealed that transition-metal catalyst could lower the reactivity of the generated nitrogen radical by the coordination of the transition metal, which allowed the selective radical/radical cross-coupling with the transient sp(3) carbon radical to construct C(sp(3))--N bonds. Various C(sp(3))-H bonds could be transformed into C(sp(3))-N bonds through this radical amidation strategy.
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Copper-catalysed oxidative Csp(3)-H methylenation to terminal olefins using DMF.
Chem. Commun. (Camb.)
PUBLISHED: 06-05-2014
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A copper-catalysed direct oxidative Csp(3)-H methylenation to terminal olefins using DMF as one carbon source was developed. In this reaction, various functional groups were well tolerated, thus providing a simple way to construct arylvinylketones and arylvinylpyridines. The preliminary mechanistic investigations revealed that CH2 was from DMF (N-CH3).
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The alteration of inflammatory markers and apoptosis on chronic prostatitis induced by estrogen and androgen.
Int Urol Nephrol
PUBLISHED: 06-02-2014
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The age-related decline of the testosterone-to-estrogen (T-to-E2) ratio in serum is associated with the increased prevalence of prostatic inflammation. The goal of the study was to induce prostatic inflammation with E2 and androgen treatment and to explore the inflammatory markers and apoptosis on prostatitis.
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A Protein-Tagging System for Signal Amplification in Gene Expression and Fluorescence Imaging.
Cell
PUBLISHED: 06-01-2014
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Signals in many biological processes can be amplified by recruiting multiple copies of regulatory proteins to a site of action. Harnessing this principle, we have developed a protein scaffold, a repeating peptide array termed SunTag, which can recruit multiple copies of an antibody-fusion protein. We show that the SunTag can recruit up to 24 copies of GFP, thereby enabling long-term imaging of single protein molecules in living cells. We also use the SunTag to create a potent synthetic transcription factor by recruiting multiple copies of a transcriptional activation domain to a nuclease-deficient CRISPR/Cas9 protein and demonstrate strong activation of endogenous gene expression and re-engineered cell behavior with this system. Thus, the SunTag provides a versatile platform for multimerizing proteins on a target protein scaffold and is likely to have many applications in imaging and controlling biological outputs.
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Effect of caffeic acid derivatives on polychlorinated biphenyls induced hepatotoxicity in male mice.
J Biomed Res
PUBLISHED: 05-31-2014
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Chronic exposure to coplanar polychlorinated biphenyls (PCBs), a potent inducer of toxic reactive oxygen species (ROS), in the environment and food can cause liver diseases. It remains unknown whether caffeic acid derivatives (CADs) exerted protective effect on PCB-induced hepatotoxicity. We sought to evaluate the activities of 3 CADs on PCB169-induced oxidative stress and DNA damage in the liver. Male ICR mice were administered with 1??mol/mL PCB169 at 5?mL/kg body weight for 2 weeks. The mice were given CADs by gastric gavage for 3 weeks. We found that PCB169 decreased the growth rate and reduced the levels of superoxide dismutase (SOD), glutathione (GSH) and GSH peroxidase (GPx). It increased the liver weight, malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels and CYP1A1 activity in the liver tissues and plasma of mice (P<0.05). Pretreatment of mice with CADs restored the above parameters to normal levels. There was a synergistic protective effect between CADs in preventing MDA and 8-OHdG formation and inducing CYP1A1 and phase II metabolism enzyme (SOD, GPx) activities (P<0.05). In conclusion, PCB169 induced hepatotoxicity and pretreatment with CADs had synergistic protective effects on liver damage.
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Numerical well testing interpretation model and applications in crossflow double-layer reservoirs by polymer flooding.
ScientificWorldJournal
PUBLISHED: 05-19-2014
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This work presents numerical well testing interpretation model and analysis techniques to evaluate formation by using pressure transient data acquired with logging tools in crossflow double-layer reservoirs by polymer flooding. A well testing model is established based on rheology experiments and by considering shear, diffusion, convection, inaccessible pore volume (IPV), permeability reduction, wellbore storage effect, and skin factors. The type curves were then developed based on this model, and parameter sensitivity is analyzed. Our research shows that the type curves have five segments with different flow status: (I) wellbore storage section, (II) intermediate flow section (transient section), (III) mid-radial flow section, (IV) crossflow section (from low permeability layer to high permeability layer), and (V) systematic radial flow section. The polymer flooding field tests prove that our model can accurately determine formation parameters in crossflow double-layer reservoirs by polymer flooding. Moreover, formation damage caused by polymer flooding can also be evaluated by comparison of the interpreted permeability with initial layered permeability before polymer flooding. Comparison of the analysis of numerical solution based on flow mechanism with observed polymer flooding field test data highlights the potential for the application of this interpretation method in formation evaluation and enhanced oil recovery (EOR).
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Spectroscopic properties of a series of Co(II) coordination polymers and the influence of Co(II) coordination environment on photoelectric property.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 04-29-2014
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Four Co(II) coordination polymers, [Co(suc)]n1, [Co(pdc)]n2, {[Co7(suc)4(OH)6(H2O)3]·8H2O}n3, {[Co(bdc)(phen)(H2O)]·H2O}n4 (H2suc=succinic acid, H2pdc=pyridine-3,4-dicarboxylic acid, H2bdc=1,2-benzenedicarboxylic acid, phen=1,10-phenanthroline) were hydrothermally synthesized and characterized by X-ray single-crystal diffraction, surface photovoltage spectroscopy (SPS), electrical conductivity, thermogravimetric analysis (TG), ultraviolet visible and near-infrared absorption spectrum (UV-Vis-NIR), infrared spectrum (IR), and elemental analysis. The structural analyses indicate that the coordination numbers of the Co(II) ions are 4, 5, 6 and 6 for the polymers 1-4, respectively. And polymers 1 and 2 exhibit 3D structure formed by suc(2-) and pdc(2-) anions bridging Co(II) ions, respectively. Polymer 3 exhibits a 2D structure with suc(2-) anions bridging seven-nuclear [Co7(OH)6(H2O)3](3-) unit and polymer 4 is a 1D structure bridged by bdc(2-) anions. The surface photoelectric properties of the cobalt polymers were mainly studied by SPS. The results of SPS reveal that all polymers possess certain photoelectric conversion property in the range of 300-800nm. The influences of the structure, coordination micro-environment of central metal ion and structural dimensionality on response bands of SPS were discussed.
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A glucose biosensor based on the synergistic action of nanometer-sized TiO2 and polyaniline.
Talanta
PUBLISHED: 04-25-2014
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Polyaniline/active carbon (PANI) and nanometer-sized TiO2 (n-TiO2) were prepared by oxidation and sol-gel methods, respectively, and were then used as a zymophore to modify a glassy carbon electrode (GCE) and a GOx/n-TiO2/PANI/GCE sensor with a synergistic effect was established. A series of performance evaluations for the modified material and sensor was studied in detail through cyclic voltammetry (CV) and a chronoamperometry (CA) method. The results showed that the sensor had a good response to glucose and that the electron of the GOx molecule was transferred directly onto the sensor, and a linear relationship between the GOx redox peak current and the sweep speed was found. The apparent transmission speed constant, k, for dissimilar electrode charges was 1.35s(-1), 95% of the maximum steady current for the GOx/n-TiO2/PANI/GCE sensor could be reached in 10s, the linear range of the detected glucose concentration was from 0.02 mM to 6.0mM, the sensitivity was 6.31 ?A mM(-1)cm(-2), and the limit of detection was 18 ?M. The sensor had good selectivity and stability and could be maintained at 82% of the initial activity for 30 days.
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[Microwave radiation induces injury to GC-2spd cells].
Zhonghua Nan Ke Xue
PUBLISHED: 04-18-2014
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To explore the impact of microwave radiation on GC-2spd cells.
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A versatile framework for microbial engineering using synthetic non-coding RNAs.
Nat. Rev. Microbiol.
PUBLISHED: 04-17-2014
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Synthetic non-coding RNAs have emerged as a versatile class of molecular devices that have a diverse range of programmable functions, including signal sensing, gene regulation and the modulation of molecular interactions. Owing to their small size and the central role of Watson-Crick base pairing in determining their structure, function and interactions, several distinct types of synthetic non-coding RNA regulators that are functional at the DNA, mRNA and protein levels have been experimentally characterized and computationally modelled. These engineered devices can be incorporated into genetic circuits, enabling the more efficient creation of complex synthetic biological systems. In this Review, we summarize recent progress in engineering synthetic non-coding RNA devices and their application to genetic and cellular engineering in a broad range of microorganisms.
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Fe-Catalysed oxidative C-H/N-H coupling between aldehydes and simple amides.
Chem. Commun. (Camb.)
PUBLISHED: 04-01-2014
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A novel oxidative coupling of aldehydes with simple amides, most likely involving a radical process, was achieved through the use of an iron catalyst. Various amides were utilized as substrates to easily construct imides by coupling with aldehydes. A catalytic cycle involving the benzoyl halide intermediate is proposed based on our experimental results.
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Revealing the metal-like behavior of iodine: an iodide-catalysed radical oxidative alkenylation.
Chem. Commun. (Camb.)
PUBLISHED: 03-19-2014
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In this work, we have described an alternative alkenylation approach to illustrate the metal-like behaviour of iodine in cross-coupling reactions. Alkenylation could proceed through iodide catalysed radical initiation, radical addition and iodine promoted alkenyl functionality recovery. Catalytic HI elimination similar to the ?-hydride elimination of transition metals was realized for the radical alkenylation of sulfonyl hydrazides. Operando IR and cyclic voltammetry experiments were carried out to confirm the crucial role of iodine in the radical alkenylation process.
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Copper-catalysed oxidative C-H/C-H coupling between olefins and simple ethers.
Chem. Commun. (Camb.)
PUBLISHED: 02-26-2014
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The first copper-catalysed oxidative alkenylation of simple ethers to construct allylic ethers was successfully achieved. Different substituted olefins and simple ethers could be cross-coupled well to generate the corresponding alkenylation products. Notably, open-chain ethers were also found to be efficient coupling partners in this reaction. This reaction is likely to proceed via a radical process.
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A reagent-free oxidative cyclization approach to indolizine derivatives from ?-picoline derivatives and nitroolefins.
Chem Asian J
PUBLISHED: 02-21-2014
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A reagent-free oxidative cyclization between ?-picoline derivatives and nitroolefins has been developed. This approach, in which the nitro group acts as an internal oxidant, provides an extremely simple, efficient, and atom-economic way to construct heteroaromatic indolizine derivatives.
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Molecular etiology of non-dominant, non-syndromic, mild-to-moderate childhood hearing impairment in Chinese Hans.
Am. J. Med. Genet. A
PUBLISHED: 02-10-2014
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Childhood hearing impairment (HI) is genetically heterogeneous. Compared with the severe-to-profound HI, the molecular etiology of mild-to-moderate HI in children has been less well characterized, especially for those not inherited in the dominant mode. In this study, we recruited 114 probands with non-dominant, non-syndromic, mild-to-moderate childhood HI. Sequencing of GJB2, SLC26A4, and MTRNR1 identified causative mutations in 30.7% (35/114), 4.4% (5/114), and 4.4% (5/114) of subjects, respectively. A majority (62.9%) of bi-allelic GJB2 mutations have non-truncating mutations in at least one allele. In 10 multiplex probands with no GJB2, SLC26A4, and MTRNR1 mutations identified, targeted next-generation sequencing (NGS) of 79 known deafness genes did not identify any additional causes. Our data showed that the molecular etiology of mild-to-moderate childhood HI is considerably different from what reported for severe-to-profound HI and far from complete for those inherited in non-dominant modes. © 2014 Wiley Periodicals, Inc.
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Aging-related neurodegeneration eliminates male courtship choice in Drosophila.
Neurobiol. Aging
PUBLISHED: 02-01-2014
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Choices between 2 options, one liked and one disliked, are effortless for an animal, whereas those among 2 equally liked options are more difficult to determine and might depend on an unknown mechanism. Here, we report that in the fruit fly Drosophila melanogaster, both younger virgin females and older ones are "liked options" to males. However, when given the choice, males tend to be fastidious and prefer younger virgin females to older ones. Besides, aging eliminates males' preference for younger mates, which can be mimicked by ectopically expressing the human amyloid precursor protein in their central nervous system. Furthermore, we examined the effect of neurodegeneration in Drosophila courtship circuit and confirmed that male courtship preference for younger mates was abrogated by neurodegeneration. Our work, thus characterizes a novel choice behavior that can be decisions after comparison and also reveals the critical role of neurodegeneration in this behavior, which provides new insights on decision-making mechanisms.
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Palladium-catalyzed oxidative carbonylation of N-allylamines for the synthesis of ?-lactams.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 01-28-2014
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?-Lactam scaffolds are considered to be ideal building blocks for the synthesis of nitrogen-containing compounds. A new palladium-catalyzed oxidative carbonylation of N-allylamines for the synthesis of ?-methylene-?-lactams is reported. DFT calculations suggest that the formation of ?-lactams via a four-membered-ring transition state is favorable.
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CO/C-H as an acylating reagent: a palladium-catalyzed aerobic oxidative carbonylative esterification of alcohols.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 01-20-2014
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A palladium-catalyzed oxidative carbonylative esterification of a variety of functionalized alcohols under base- and ligand-free conditions has been demonstrated. A CO/olefin combination was utilized as the acylating reagent with O2 as a benign oxidant. Notably, the scope of the substrate alcohols has been greatly broadened.
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A new surgical procedure for palmar hyperhidrosis: is it possible to perform endoscopic sympathectomy under deep sedation without intubation?
Eur J Cardiothorac Surg
PUBLISHED: 01-19-2014
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Palmar hyperhidrosis (PH) is a common dysfunctional disorder, with endoscopic thoracic sympathectomy (ETS) being the most popular treatment method. However, until now, there is little improvement to this technique. In this paper, we present a new alternative to the conventional surgical method.
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Synthesis of 6-acyl phenanthridines by oxidative radical decarboxylation-cyclization of ?-oxocarboxylates and isocyanides.
Chem. Commun. (Camb.)
PUBLISHED: 01-14-2014
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A silver catalysed synthesis of 6-acyl phenanthridines by oxidative radical decarboxylation-cyclization of ?-oxocarboxylates and isocyanides was developed. This reaction provided a novel method to realize C1 insertion via a radical process and various functional groups were well-tolerated.
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Jellyfish skin polysaccharides: extraction and inhibitory activity on macrophage-derived foam cell formation.
Carbohydr Polym
PUBLISHED: 01-11-2014
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In this work, response surface methodology was used to determine optimum conditions for extraction of polysaccharides from jellyfish skin (JSP). The optimum parameters were found to be raw material to water ratio 1:7.5 (w/v), extraction temperature 100°C and extraction time 4h. Under these conditions, the JSP yield reached 1.007 mg/g. Papain (15 U/mL) in combination with Sevag reagent was beneficial in removing proteins from JSP. After precipitation with ethanol at final concentration of 40%, 60% and 80% in turn, three polysaccharide fractions of JSP1, JSP2 and JSP3 were obtained from JSP, respectively. The three fractions exhibited different physicochemical properties with respect to molecular weight distribution, monosaccharide composition, infrared absorption spectra, and glycosyl bond composition. In addition, JSP3 showed strong inhibitory effects on oxidized low-density lipoprotein (oxLDL) induced conversion of macrophages into foam cells, which possibly attributed to the down-regulation of some atherogenesis-related gene expressions.
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Interleukin-6 -634C/G polymorphism is associated with lung cancer risk: a meta-analysis.
Tumour Biol.
PUBLISHED: 01-10-2014
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Several studies have examined the associations of polymorphisms in interleukin-6 (IL6) with lung cancer (LC) risk. However, the results were conflicting. Thus, a meta-analysis was conducted to determine the relationship between IL6 polymorphisms and LC risk. Databases including PubMed, EMBASE, Wanfang, and China National Knowledge Infrastructure (CNKI) were searched. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Thirteen studies were included in this meta-analysis. Overall, a significant association between IL6 -634C/G polymorphism and LC susceptibility was observed for GG?+?CG vs. CC (OR?=?1.33, 95% CI 1.20-1.47, P?
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Direct observation of reduction of Cu(II) to Cu(I) by terminal alkynes.
J. Am. Chem. Soc.
PUBLISHED: 01-10-2014
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X-ray absorption spectroscopy and in situ electron paramagnetic resonance evidence were provided for the reduction of Cu(II) to Cu(I) species by alkynes in the presence of tetramethylethylenediamine (TMEDA), in which TMEDA plays dual roles as both ligand and base. The structures of the starting Cu(II) species and the obtained Cu(I) species were determined as (TMEDA)CuCl2 and [(TMEDA)CuCl]2 dimer, respectively.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.