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81.
α-Substituted Phosphonates. 40. 1-Trimethylammonium-1-diethylphosphono-1-cyanomethylid, a Stable N-Ylid Diethyl-1-dimethylamino-1-cyanomethanephosphonate 4 can be alkylated on nitrogen to the quarternary ammoniumsalts 5 , which by C-deprotonation gives the stable N-ylid 8 . The N-ylid 8 behaves inert against carbonyl compounds and acylating agents, but can be C-alkylated and — involving an ester-dealkylation — C-chlorinated. 相似文献
82.
α-Substituted Phosphonates. 39. Methane-diphosphonic Esters by U.V.-Induced Michaelis-Becker-Reaction Dibromomethane resp. chlorbromomethane reacts with sodium dialkyl phosphite in heptane-/liq.NH3 or in liq. NH3 by u.v. irradiation at low temperatures to give in good yields methane diphosphonic acid tetraalkylesters 1 . In the same manner with sodium diethyl thionophosphite the corresponding methane-bis-thiophosphonic acid tetraethylester 4 is obtained. 相似文献
83.
Hyperketonemia interferes with the metabolic regulation in dairy cows. It is assumed that metabolic and endocrine changes during hyperketonemia also affect metabolic adaptations during inflammatory processes. We therefore studied systemic and local intramammary effects of elevated plasma β-hydroxybutyrate (BHBA) before and during the response to an intramammary lipopolysaccharide (LPS) challenge. Thirteen dairy cows received intravenously either a Na-dl-β-OH-butyrate infusion (n = 5) to achieve a constant plasma BHBA concentration (1.7 ± 0.1 mmol/L), with adjustments of the infusion rates made based on immediate measurements of plasma BHBA every 15 min, or an infusion with a 0.9% NaCl solution (control; n = 8) for 56 h. Infusions started at 0900 h on d 1 and continued until 1700 h 2 d later. Two udder quarters were challenged with 200 μg of Escherichia coli LPS and 2 udder quarters were treated with 0.9% saline solution as control quarters at 48 h after the start of infusion. Blood samples were taken at 1 wk and 2 h before the start of infusions as reference samples and hourly during the infusion. Mammary gland biopsies were taken 1 wk before, and 48 and 56 h (8 h after LPS challenge) after the start of infusions. The mRNA abundance of key factors related to BHBA and fatty acid metabolism, and glucose transporters was determined in mammary tissue biopsies. Blood samples were analyzed for plasma glucose, BHBA, nonesterified fatty acid, urea, insulin, glucagon, and cortisol concentrations. Differences were not different for effects of BHBA infusion on the mRNA abundance of any of the measured target genes in the mammary gland before LPS challenge. Intramammary LPS challenge increased plasma glucose, cortisol, glucagon, and insulin concentrations in both groups but increases in plasma glucose and glucagon concentration were less pronounced in the Na-dl-β-OH-butyrate infusion group than in controls. In response to LPS challenge, plasma BHBA concentration decreased in controls and decreased also slightly in the BHBA-infused animals because the BHBA concentration could not be fully maintained despite a rapid increase in BHBA infusion rate. The change in mRNA abundance of citrate synthase in LPS quarters was significant between the 2 treatment groups. The results indicate that elevated circulating BHBA concentration inhibits gluconeogenesis before and during immune response to LPS challenge, likely because BHBA can replace glucose as an energy source. 相似文献
84.
R.J. van Hoeij J. Dijkstra R.M. Bruckmaier J.J. Gross T.J.G.M. Lam G.J. Remmelink B. Kemp A.T.M. van Knegsel 《Journal of dairy science》2017,100(10):8544-8564
Omitting the dry period (DP) generally reduces milk production in the subsequent lactation. The aim of this study was to evaluate the effect of dietary energy source—glucogenic (G) or lipogenic (L)—and energy level—standard (std) or low—on milk production; energy balance (EB); lactogenic hormones insulin, insulin-like growth factor 1 (IGF-1), and growth hormone (GH); and lactation curve characteristics between wk 1 and 44 postpartum in cows after a 0-d or 30-d DP. Cows (n = 110) were assigned randomly to 3 transition treatments: a 30-d DP with a standard energy level required for expected milk yield [30-d DP(std)], a 0-d DP with the same energy level as cows with a 30-d DP [0-d DP(std)], and a 0-d DP with a low energy level [0-d DP(low)]. In wk 1 to 7, cows were fed the same basal ration but the level of concentrate increased to 6.7 kg/d for cows fed the low energy level and to 8.5 kg/d for cows fed the standard energy level in wk 4. From wk 8 postpartum onward, cows received a G ration (mainly consisting of corn silage and grass silage) or an L ration (mainly consisting of grass silage and sugar beet pulp) with the same energy level contrast (low or std) as in early lactation. Cows fed the G ration had greater milk, lactose, and protein yields, lower milk fat percentage, greater dry matter and energy intakes, and greater plasma IGF-1 concentration compared with cows fed the L ration. Dietary energy source did not affect EB or lactation curve characteristics. In cows with a 0-d DP, the reduced energy level decreased energy intake, EB, and weekly body weight gain, but did not affect milk production or lactation curve characteristics. A 30-d DP resulted in a greater total predicted lactation yield, initial milk yield after calving, peak milk yield, energy intake, energy output in milk, days to conception [only when compared with 0-d DP(low)], plasma GH concentration [only when compared with 0-d DP(std)], and decreased weekly body weight gain compared with a 0-d DP. A 30-d DP decreased both the increasing and the declining slope parameters of the lactation curve and the relative rate of decline in milk yield (indicating greater lactation persistency) compared with a 0-d DP, and decreased plasma insulin and IGF-1 concentration, and EB. In conclusion, feeding a G ration after wk 7 in milk improved energy intake and milk production, but did not affect EB compared with an L ration. For cows without a DP, a reduced dietary energy level did not affect milk production and lactation curve characteristics, but did decrease EB and weekly body weight gain. A 30-d DP increased milk yield and lactation persistency, but decreased milk fat and protein content, EB, and plasma insulin and IGF-1, compared with a 0-d DP. 相似文献
85.
Photoreduction of Shewanella oneidensis Extracellular Cytochromes by Organic Chromophores and Dye‐Sensitized TiO2 下载免费PDF全文
Emma V. Ainsworth Dr. Colin W. J. Lockwood Dr. Gaye F. White Dr. Ee Taek Hwang Dr. Tsubasa Sakai Manuela A. Gross Prof. David J. Richardson Dr. Thomas A. Clarke Dr. Lars J. C. Jeuken Dr. Erwin Reisner Prof. Julea N. Butt 《Chembiochem : a European journal of chemical biology》2016,17(24):2324-2333
The transfer of photoenergized electrons from extracellular photosensitizers across a bacterial cell envelope to drive intracellular chemical transformations represents an attractive way to harness nature's catalytic machinery for solar‐assisted chemical synthesis. In Shewanella oneidensis MR‐1 (MR‐1), trans‐outer‐membrane electron transfer is performed by the extracellular cytochromes MtrC and OmcA acting together with the outer‐membrane‐spanning porin ? cytochrome complex (MtrAB). Here we demonstrate photoreduction of solutions of MtrC, OmcA, and the MtrCAB complex by soluble photosensitizers: namely, eosin Y, fluorescein, proflavine, flavin, and adenine dinucleotide, as well as by riboflavin and flavin mononucleotide, two compounds secreted by MR‐1. We show photoreduction of MtrC and OmcA adsorbed on RuII‐dye‐sensitized TiO2 nanoparticles and that these protein‐coated particles perform photocatalytic reduction of solutions of MtrC, OmcA, and MtrCAB. These findings provide a framework for informed development of strategies for using the outer‐membrane‐associated cytochromes of MR‐1 for solar‐driven microbial synthesis in natural and engineered bacteria. 相似文献
86.
α-Substituted Phosphonates. 43. Synthesis and Reactivity of 1,2,3,4-Tetrahydroisochinolin-1-phosphonates N-Alkyl- and N-arylsubstituted 1,2,3,4-tetrahydroisochinolin-1-phosphonates 1 have been synthesized from the corresponding 3,4-dihydroisochinoliniumbromides 7 and triethyl-phosphite. The N-unsubstituted 1,2,3,4-tetrahydroisochinolin-1-phosphonate 10 is available starting from the 1,2,3,4-tetrahydroisochinolin-1-phosphonic acid by esterification with triethylformate and splitting off the formyl group of the primarily formed N-formyl derivative 14 . – N-Quarternated tetrahydroisochinolines 19 and the 1-phosphorylated derivatives 17 , respectively react with triethyl-phosphite in an unexpected way by dealkylation and not by splitting off the isochinolinring. – By Horner-synthesis with 1 the 1-aralkylidene-isochinolines 23 are available in moderate yields. 相似文献
87.
Donggeon Han Yasser Khan Jonathan Ting Simon M. King Nir Yaacobi‐Gross Martin J. Humphries Christopher J. Newsome Ana C. Arias 《Advanced materials (Deerfield Beach, Fla.)》2017,29(22)
A method to print two materials of different functionality during the same printing step is presented. In printed electronics, devices are built layer by layer and conventionally only one type of material is deposited in one pass. Here, the challenges involving printing of two emissive materials to form polymer light‐emitting diodes (PLEDs) that emit light of different wavelengths without any significant changes in the device characteristics are described. The surface‐energy‐patterning technique is utilized to print materials in regions of interest. This technique proves beneficial in reducing the amount of ink used during blade coating and improving the reproducibility of printed films. A variety of colors (green, red, and near‐infrared) are demonstrated and characterized. This is the first known attempt to print multiple materials by blade coating. These devices are further used in conjunction with a commercially available photodiode to perform blood oxygenation measurements on the wrist, where common accessories are worn. Prior to actual application, the threshold conditions for each color are discussed, in order to acquire a stable and reproducible photoplethysmogram (PPG) signal. Finally, based on the conditions, PPG and oxygenation measurements are successfully performed on the wrist with green and red PLEDs. 相似文献
88.
89.
This special issue is the result of sustained and highly collaborative efforts to improve the use of remotely sensed data to inform management of protected areas. The 15 papers in the issue address a diverse range of topics. These papers provide a conceptual basis and a framework for establishing monitoring programs, techniques and methods to make operational the use of remotely sensed data, case studies, and synthesis papers liking remotely sensed data to models used to inform ecological assessments. Studies in this issue necessarily confront the universal challenges of scale, both spatial and temporal, and the sometimes tenuous link between observed patterns and significant ecological process. A clear message is that the information needs of resource managers require information across scales, and these information demands will continue to motivate advances in the collection and analysis of remotely sensed data. This compilation of papers is unusual in (1) articulating a basic, if somewhat technical, foundation of remote sensing that is required for resource managers to effectively collaborate with remote sensing specialists, and (2) providing a framework for addressing monitoring resource issues that is likely to be of interest to many remote sensing specialists. We hope these papers inspire broader use of remotely sensed data to manage the increasingly rare and valuable resources in protected areas around the world. 相似文献
90.