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151.
Facile synthesis of cis and trans olefinic analogues of oxytocin 1 that have carbon in place of sulfur is achieved via ring-closing metathesis (RCM) on a resin-bound linear precursor peptide. Hydrogenation of the cis olefin, 3, proceeds selectively to generate the previously reported saturated derivative 5. Biological testing on rat uterus strips shows that cis compound 3 has an EC50 value of 38 ng/mL (EC50 for oxytocin is 2.7 ng/mL) whereas 5 and trans olefin 4 are less active. [reaction--see text] 相似文献
152.
This paper presents a model of lead-time policies for a production system, such as an integrated steel mill, in which the bottleneck process requires a minimum batch size. An accurate understanding of internal lead-time quotations is necessary for making good customer delivery-date promises, which must take into account processing time, queueing time and time for arrival of the requisite volume of orders to complete the minimum batch size requirement. The problem is modeled as a stochastic dynamic program with a large state space. A computational study demonstrates that lead time for an arriving order should generally be a decreasing function of the amount of that product already on order (and waiting for minimum batch size to accumulate), which leads to a very fast and accurate heuristic. The computational study also provides insights into the relationship between lead-time quotation, arrival rate, and the sensitivity of customers to the length of delivery promises. 相似文献
153.
Kristin Geddes Gary Adamson Neal Dube Susan Crathern Richard C. King 《Rapid communications in mass spectrometry : RCM》2009,23(9):1303-1312
This paper describes an automated workflow for the determination of selected reaction monitoring (SRM) transitions and optimum mass spectrometric (MS) instrument parameters. The approach uses a Nanomate from Advion Biosciences for automated infusion of small amounts of sample in combination with Automaton optimization software from Sciex. The results are stored in the Analyst software Compound Database for automated acquisition method building. Comparisons are presented between the more traditional optimization methods of manual flow injection optimization, Autotune infusion optimization, Automaton flow injection optimization and the Nanomate–Automaton optimization approach. Data is also presented to show that acquisition methods developed on the Sciex model API3000 instrument can be effectively transferred to the Sceix API4000 and API5000 model instruments. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
154.
Susan Jacob Melodie L. Schmitt Mark E. Schlesinger 《Journal of Thermal Analysis and Calorimetry》2010,100(3):897-900
High-temperature differential scanning calorimetry was used to investigate the thermodynamic parameters of the γ–β and β–α transitions in calcium pyrophosphate (Ca2P2O7). The measured enthalpy of transition compared well with previous results when higher heating rates (≥20 K min?1) were used. Recommendations for optimal use of HTDSC in high-temperature phase transition measurements are presented. 相似文献
155.
156.
Fornberg Bengt; Flyer Natasha; Hovde Susan; Piret Cecile 《IMA Journal of Numerical Analysis》2008,28(1):121-142
157.
Zeily Nurachman Dewi Susan Brataningtyas Hartati Lily Maria Goretty Panggabean 《Applied biochemistry and biotechnology》2012,168(5):1065-1075
The potential of the tropical marine benthic-diatom Navicula sp. for biodiesel feedstock was investigated. Growth profiles were analyzed by changing nutrient compositions in three different media (Walne, plain seawater, and modified seawater) and irradiance intensities. Navicula sp. cells showed significant growth in Walne and modified seawater medium but not in plain seawater medium. The microalgae grew well in a pH range of 7.8?C8.4, and the cells were very sensitive to the intensity of direct sunlight exposure. The average cell concentration obtained from the cultures in plain seawater, Walne, and modified seawater media at the beginning of the stationary phase was 0.70, 2.17, and 2.54?g/L, respectively. Electron spray ionization-ion trap-mass spectrometry showed that the triacylglycerols of the algae oil were identified as POP (palmitic-oleic-palmitic), POO (palmitic-oleic-oleic), and OOLn (oleic-oleic-linoleic). The oil productivity of Navicula sp. cultivated in Walne and modified seawater media was 90 and 124???L?L?1 culture d?1. The Navicula sp. biodiesel exhibited a kinematic viscosity of 1.299?mm2/s, density of 0.8347?g/mL, and internal energy of 0.90?kJ/mL. 相似文献
158.
Simon J. Garden Christopher Glidewell John N. Low Susan A. McWilliam Angelo C. Pinto Janet M. S. Skakle Jose C. Torres James L. Wardell 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(10):1212-1214
In the title compound, C7H7IN2O2, the O atoms of the nitro group are disordered over two sets of sites and there is evidence that the intramolecular I⃛nitro interaction is repulsive. In the crystal structure, there are neither strong hydrogen bonds, nor intermolecular I⃛nitro interactions, nor aromatic π–π-stacking interactions. 相似文献
159.
James Elver Johnson Richard Hodzi Susan L. Todd Patrice De Meester Shirley S. C. Chu 《Journal of heterocyclic chemistry》1986,23(5):1423-1426
Alkylation of potassium p-nitrobenzohydroxamate with 1,4-dibromobutane gave 2-(p-nitrobenzoyl)tetrahydro-2H-1,2-oxazine (3). The X-ray crystal structure of 3 has been determined. The crystals are monoclinic, space group P21/n with a = 6.749(1), b = 7.644(1), c = 21.557(2)Å, β = 98.89(1), V = 1098.8(2)Å3 and Z = 4. The structure, which was refined to R = 0.039 using 1340 observed reflections, shows the oxazine and carbonyl oxygen atoms trans to each other. Alkylation of potassium benzohydroxamate with 1,3-dibromobutane gave a mixture of 3-methyl-2-benzoyloxazolidine (4) and 5-methyl-2-benzoyloxazolidine (5). The 1H and 13C nmr spectra of the mixture of 4 and 5 indicates that these cyclic hydroxamates exist predominantly in the s-trans conformation. 相似文献
160.
George D. Bachand Amy Allen Marlene Bachand Komandoor E. Achyuthan Jean Clare Seagrave Susan M. Brozik 《Journal of nanoparticle research》2012,14(10):1-10
This study explores the viability of rare earth-doped zirconia nanophosphors as probable candidates for white light emission. Undoped ZrO2 and single- and double-doped ZrO2:M (where M?=?Tb3+ and Eu3+) nanophosphors have been synthesized using a simple sonochemical process. The products were characterized using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), and photoluminescence spectrophotometry. The SEM micrographs show that resultant nanoparticles have dendritic shape. TEM and HRTEM studies showed that the size of the majority of the nanoparticles were around 28?±?5?nm. Characteristic blue and green emission from Tb3+ ions and red from Eu3+ dopant ions were observed. The CIE coordinates of the double-doped ZrO2:Tb3+ (1.2?%):Eu3+ (0.8?%) nanophosphor lie in the white light region of the chromaticity diagram and show promise as good phosphor materials for new lighting devices. 相似文献