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101.
Maria M Velencoso Agustin SB Gonzalez Joaquin C García‐Martínez Maria J Ramos Antonio De Lucas Juan F Rodriguez 《Polymer International》2013,62(5):783-790
A simple strategy for the synthesis and functionalization of polyurethanes is described. Anionic ring‐opening polymerization was combined with ‘click’ chemistry to synthesize polyols with fluorescent properties. This route allows the incorporation of a wide range of functionalities in the polyols with an easy, clean and highly selective process compatible with several types of functional groups. The proposed strategy opens the way to the production, in a cost‐effective way, of ‘smart’ polyurethanes with non‐conventional properties like fire retardancy, antimite properties, antibacterial properties, etc. Alkynyl groups were introduced into the polyol chains by the controlled addition of glycidyl propargyl ether as co‐monomer during a conventional anionic ring‐opening copolymerization with propylene oxide. Subsequently 4‐azidomethyl‐7‐methoxycoumarin molecules were introduced onto the alkynyl‐polyether polyols by copper‐catalysed cycloaddition reactions to produce end‐functionalized polyols. The chemical structure of the novel polyols was characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography with triple detection and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy. These characterization techniques confirmed the presence of a considerable amount of functional groups in the structure of the polyols. Finally, various fluorescent rigid foams, based on the functionalized polyols, were synthesized. Copyright © 2012 Society of Chemical Industry 相似文献
102.
Greg Mann Dr. Liujie Huo Sebastian Adam Dr. Brunello Nardone Dr. Jeremie Vendome Prof. Nicholas James Westwood Prof. Rolf Müller Dr. Jesko Koehnke 《Chembiochem : a European journal of chemical biology》2016,17(23):2286-2292
The bottromycins are a family of highly modified peptide natural products, which display potent antimicrobial activity against Gram‐positive bacteria, including methicillin‐resistant Staphylococcus aureus. Bottromycins have recently been shown to be ribosomally synthesized and post‐translationally modified peptides (RiPPs). Unique amongst RiPPs, the precursor peptide BotA contains a C‐terminal “follower” sequence, rather than the canonical N‐terminal “leader” sequence. We report herein the structural and biochemical characterization of BotP, a leucyl‐aminopeptidase‐like enzyme from the bottromycin pathway. We demonstrate that BotP is responsible for the removal of the N‐terminal methionine from the precursor peptide. Determining the crystal structures of both apo BotP and BotP in complex with Mn2+ allowed us to model a BotP/substrate complex and to rationalize substrate recognition. Our data represent the first step towards targeted compound modification to unlock the full antibiotic potential of bottro‐ mycin. 相似文献
103.
Eberl HC Mann M Vermeulen M 《Chembiochem : a European journal of chemical biology》2011,12(2):224-234
Mass spectrometry has made many contributions to the chromatin field through the mapping of histone modifications and the identification of protein complexes involved in gene regulation. MS-based proteomics has now evolved from the identification of single protein spots in gels to the identification and quantification of thousands of proteins in complex mixtures. Quantitative approaches also allow comparative and time-resolved analysis of post-translational modifications. An important emerging field is the unbiased interaction analysis of proteins with other proteins, defined protein modifications, specific DNA and RNA sequences, and small molecules. Quantitative proteomics can also accurately monitor whole proteome changes in response to perturbation of the gene expression machinery. We provide an up-to-date review of modern quantitative proteomic technology and its applications in the field of epigenetics. 相似文献
104.
Homoserine Lactones,Methyl Oligohydroxybutyrates,and Other Extracellular Metabolites of Macroalgae‐Associated Bacteria of the Roseobacter Clade: Identification and Functions 下载免费PDF全文
Lisa Ziesche Hilke Bruns Marco Dogs Laura Wolter Florian Mann Prof. Irene Wagner‐Döbler Prof. Dr. Thorsten Brinkhoff Prof. Stefan Schulz 《Chembiochem : a European journal of chemical biology》2015,16(14):2094-2107
Twenty‐four strains of marine Roseobacter clade bacteria were isolated from macroalgae and investigated for the production of quorum‐sensing autoinducers, N‐acylhomoserine lactones (AHLs). GC/MS analysis of the extracellular metabolites allowed us to evaluate the release of other small molecules as well. Nineteen strains produced AHLs, ranging from 3‐OH‐C10:0‐HSL (homoserine lactone) to (2E,11Z)‐C18:2‐HSL, but no specific phylogenetic or ecological pattern of individual AHL occurrence was observed when cluster analysis was performed. Other identified compounds included indole, tropone, methyl esters of oligomers of 3‐hydroxybutyric acid, and various amides, such as N‐9‐hexadecenoylalanine methyl ester (9‐C16:1‐NAME), a structural analogue of AHLs. Several compounds were tested for their antibacterial and antialgal activity on marine isolates likely to occur in the habitat of the macroalgae. Both AHLs and 9‐C16:1‐NAME showed high antialgal activity against Skeletonema costatum, whereas their antibacterial activity was low. 相似文献
105.
Soy protein isolate (SPI) was mixed with 10, 20, 30, and 40 wt% of corn cob by solvent casting method. The SPI/corn cob biocomposite films were tested for tensile, morphological, thermal, and enzymatic biodegradation properties. The result demonstrated that, as corn cob content increases, the tensile strength, modulus of elasticity, and thermal stability of biocomposite films increased, but elongation at break and enzymatic biodegradability decreased. Nevertheless, the treated SPI/corn cob biocomposite films with acrylic acid showed improvement in tensile strength, elongation at break, modulus of elasticity, thermal properties, and resistance to biodegradability by enzyme over the untreated SPI/corn cob biocomposite films . J. VINYL ADDIT. TECHNOL., 24:68–74, 2018. © 2015 Society of Plastics Engineers 相似文献
106.
Rekha Mann Kiranmala Laishram Sheikh Ashfaq Ahmed Neelam Malhan 《Ceramics International》2012,38(5):4131-4135
A novel approach of neodymium ion doped yttrium oxide (Nd:Y2O3) amorphous precursor compaction and sintering is being reported for the first time. Precursor of 2 at.% Nd3+ doped Y2O3 was synthesized by gelation of sol of yttrium and neodymium nitrates with l-alanine at 80 °C for 16 h followed by gel combustion in microwave. A part of microwave precursor was heat treated at 700 °C for 5 h to give the partially crystalline Nd:Y2O3 amorphous precursor. Thermogravimetric analysis (TGA) of partially crystalline amorphous precursor of Nd:Y2O3 gave 8.5% total weight loss indicating removal of maximum organics. X-Ray diffraction (XRD) showed broad peaks indicating incomplete crystallization of cubic Nd:Y2O3. Morphology was found to be close to spherical with particles in size range 17–19 nm by TEM. Another part of microwave precursor on calcination at 1000 °C for 3 h led to formation of fully crystalline Nd:Y2O3 with particles in size range of 35–85 nm. Both partially crystalline amorphous precursor and fully crystalline Nd:Y2O3 were compacted at 400 MPa by cold isostatic press and sintered at 1750 °C for 10 h under vacuum (10?5 mbar). The partially crystalline Nd:Y2O3 amorphous precursor densified to 99% with 65% transmission at 2500 nm (0.5 mm thickness) compared to 96% densification with 34% transmission for fully crystalline Nd:Y2O3 without any sintering aids. Retention of cubic phase purity of Y2O3 was observed in both the ceramic pellets post sintering by XRD. Good grain fusion with grain growth to ≤2 μm was observed by scanning electron microscope (SEM) for partially crystalline Nd:Y2O3 amorphous precursor. Thus partially crystalline Nd:Y2O3 amorphous precursor nanopowders, with homogeneous close to spherical fine particles and high reactivity due to ionic mobility of amorphous phase, led to better densification. 相似文献
107.
B. K. Pant Vivek Arya B. S. Mann 《Journal of Materials Engineering and Performance》2012,21(6):1051-1055
This article deals with plasma ion-nitrocarburising and high power diode laser (HPDL) surface treatment of 13Cr4Ni and X10CrNiMoV1222 martensitic stainless steels to enhance their cavitation erosion resistance. These steels are commonly used in hydro turbines and boiler feed pumps. These treated steels have been evaluated for cavitation erosion resistance and it has been observed that the plasma ion-nitrocarburising process has significantly enhanced the cavitation erosion resistance as compared to untreated steel whereas HPDL-treated steels have shown marginal improvement. This is due to formation of high hardness nitrides during nitrocarburising and formation of moderate hardness martensitic phase due to rapid heating and cooling rates involved in HPDL treatment. The cavitation erosion and micro-hardness data of plasma ion-nitrocarburized as well as HPDL-treated steel samples and their comparison with hard deposits such as stellite and HVOF coating form the main part of the article. 相似文献
108.
As meat is a rich source of the omega-3 fatty acid docosapentaenoic acid (DPA) and Australians consume six times more meat than fish, investigation of the potential health benefit of DPA is warranted. The aims were to compare the effects of seal oil supplementation with fish oil, on measures of plasma lipids and blood pressure in hypertriglyceridaemic subjects. Forty-eight volunteers were recruited from the Wollongong community and were randomly allocated to one of three groups either receiving 1 g/day of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) using one of three oils: seal oil capsules (340 mg eicosapentaenoic acid (EPA), 230 mg DPA, 450 mg DHA), fish oil capsules (210 mg EPA, 30 mg DPA, 810 mg DHA) or placebo capsules (containing sunola oil) for 6 weeks. Plasma triglycerides remained unchanged in the placebo group, whilst reductions of 7 and 14% (P < 0.05) were seen in the fish oil and seal oil groups respectively. Systolic blood pressure improved by 8 and 5 mmHg with seal oil and fish oil respectively (P < 0.05). The mean arterial pressure was significantly lower after seal oil supplementation (P < 0.005) compared with the placebo group. These results indicate that seal oil is as effective as fish oil in lowering plasma triglycerides and blood pressure. 相似文献
109.
Synthesis of Carbonated Vernonia Oil 总被引:3,自引:0,他引:3
Noel Mann Sharathkumar K. Mendon James W. Rawlins Shelby F. Thames 《Journal of the American Oil Chemists' Society》2008,85(8):791-796
The research objective was to determine whether naturally occurring epoxy functional vernonia oil would result in lower viscosity
compounds after converting the virgin oil into the cyclic carbonate using supercritical carbon dioxide as the reactant. The
cyclic carbonate was produced using relatively mild conditions as described in the paper. Carbonated vernonia oil retains
the characteristic low viscosity of vernonia oil, and offers potential as a valuable, biobased intermediate for synthesizing
low viscosity resins. 相似文献
110.
Damien Hunter Kee Heng Navdeep Mann Ravinder Anand-Ivell Richard Ivell 《International journal of molecular sciences》2021,22(8)
Xenobiotic exposure during pregnancy and lactation has been linked to perinatal changes in male reproductive outcomes and other endocrine parameters. This pilot study wished to assess whether brief maternal exposure of rats to xenobiotics dibutyl phthalate (DBP) or diethylstilbestrol (DES) might also cause long-term changes in hypothalamic gene expression or in reproductive behavior of the resulting offspring. Time-mated female Sprague Dawley rats were given either DBP (500 mg/kg body weight, every second day from GD14.5 to PND6), DES (125 µg/kg body weight at GD14.5 and GD16.5 only), or vehicle (n = 8–12 per group) and mild endocrine disruption was confirmed by monitoring postnatal anogenital distance. Hypothalamic RNA from male and female offspring at PND10, PND24 and PND90 was analyzed by qRT-PCR for expression of aromatase, oxytocin, vasopressin, ER-alpha, ER-beta, kisspeptin, and GnRH genes. Reproductive behavior was monitored in male and female offspring from PND60 to PND90. Particularly, DES treatment led to significant changes in hypothalamic gene expression, which for the oxytocin gene was still evident at PND90, as well as in sexual behavior. In conclusion, maternal xenobiotic exposure may not only alter endocrine systems in offspring but, by impacting on brain development at a critical time, can have long-term effects on male or female sexual behavior. 相似文献