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91.
Benzanilides containing two or more potentially stereogenic amide axes exist in solution as mixtures of conformers which are detectable by NMR. For simple tertiary benzanilides carrying an ortho substituent on each ring, conformational control can be high (up to about 10:1) providing the substituents are large, indicating that the two axes are in conformational communication with one another. For more complex diamides, conformational communication breaks down, and mixtures of conformers are evident by NMR. 相似文献
92.
Mezcua M Agüera A Lliberia JL Cortés MA Bagó B Fernández-Alba AR 《Journal of chromatography. A》2006,1109(2):222-227
Ultra performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UPLC-MS/MS) has been applied for the accurate and rapid analysis of nine trace level priority pesticides in water. The UPLC technology, based on the use of columns packed with 1.7 microm porous particles combined with higher pressures than those conventionally applied in HPLC, enabled to improve in peak resolution, sensitivity and speed of analysis. UPLC chromatograms showed very sharp peaks with less than 2 s wide at the base, except for alachlor. This enhanced efficiency resulted in an increased separation speed of the whole UPLC-MS/MS procedure that required less than 5 min. Limits of detection, determined for 300 ml water samples after SPE preconcentration were in the range between 0.1 and 20 ng/L. The presence of matrix effects or ion suppression was checked by the obtaining of calibration curves in both pure solvent and matrix matched standards. Other performance characteristics of the method, such as linearity and precision were also satisfactory. Finally, the method was successfully applied to the analysis of two water samples from an inter-laboratory exercise. 相似文献
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Marta Reig Cristian Gozálvez Dr. Vygintas Jankauskas Dr. Valentas Gaidelis Dr. Juozas V. Grazulevicius Dr. Lluís Fajarí Dr. Luis Juliá Dr. Dolores Velasco 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18551-18558
A series of neutral long‐lived purely organic radicals based on the stable [4‐(N‐carbazolyl)‐2,6‐dichlorophenyl]bis(2,4,6‐trichlorophenyl)methyl radical adduct (Cbz‐TTM) is reported herein. All compounds exhibit ambipolar charge‐transport properties under ambient conditions owing to their radical character. High electron and hole mobilities up to 10?2 and 10?3 cm2 V?1 s?1, respectively, were achieved. Xerographic single‐layered photoreceptors were fabricated from the radicals studied herein, exhibiting good xerographic photosensitivity across the visible spectrum. 相似文献
94.
A Photoactivatable Platinum(IV) Anticancer Complex Conjugated to the RNA Ligand Guanidinoneomycin 下载免费PDF全文
Dr. Evyenia Shaili Marta Fernández‐Giménez Savina Rodríguez‐Astor Albert Gandioso Lluís Sandín Carlos García‐Vélez Dr. Anna Massaguer Dr. Guy J. Clarkson Dr. Julie A. Woods Prof. Peter J. Sadler Dr. Vicente Marchán 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18474-18486
A photoactivatable platinum(IV) complex, trans,trans,trans‐[Pt(N3)2(OH)(succ)(py)2] (succ=succinylate, py=pyridine), has been conjugated to guanidinoneomycin to study the effect of this guanidinum‐rich compound on the photoactivation, intracellular accumulation and phototoxicity of the pro‐drug. Surprisingly, trifluoroacetic acid treatment causes the replacement of an azido ligand and the axial hydroxide ligand by trifluoroacetate, as shown by NMR spectroscopy, MS and X‐ray crystallography. Photoactivation of the platinum–guanidinoneomycin conjugate in the presence of 5′‐guanosine monophosphate (5′‐GMP) led to the formation of trans‐[Pt(N3)(py)2(5′‐GMP)]+, as does the parent platinum(IV) complex. Binding of the platinum(II) photoproduct {PtN3(py)2}+ to guanine nucleobases in a short single‐stranded oligonucleotide was also observed. Finally, cellular uptake studies showed that guanidinoneomycin conjugation improved the intracellular accumulation of the platinum(IV) pro‐drug in two cancer cell lines, particularly in SK‐MEL‐28 cells. Notably, the higher phototoxicity of the conjugate in SK‐MEL‐28 cells than in DU‐145 cells suggests a degree of selectivity towards the malignant melanoma cell line. 相似文献
95.
Elena de las Heras Ester Boix-Garriga Francesca Bryden Montserrat Agut Margarita Mora M. Lluïsa Sagristá Ross W. Boyle Norbert Lange Santi Nonell 《Photochemistry and photobiology》2020,96(3):570-580
Active targeting strategies are currently being extensively investigated in order to enhance the selectivity of photodynamic therapy. The aim of the present research was to evaluate whether the external decoration of nanopolymeric carriers with targeting peptides could add more value to a photosensitizer formulation and increase antitumor therapeutic efficacy and selectivity. To this end, we assessed PLGA-PLA-PEG nanoparticles (NPs) covalently attached to a hydrophilic photosensitizer 5-[4-azidophenyl]-10,15,20-tri-(N-methyl-4-pyridinium)porphyrinato zinc (II) trichloride (ZnTriMPyP) and also to c(RGDfK) peptides, in order to target αvβ3 integrin-expressing cells. In vitro phototoxicity investigations showed that the ZnTriMPyP-PLGA-PLA-PEG-c(RGDfK) nanosystem is effective at submicromolar concentrations, is devoid of dark toxicity, successfully targets αvβ3 integrin-expressing cells and is 10-fold more potent than related nanosystems where the PS is occluded instead of covalently bound. 相似文献
96.
Ceria–Zirconia Particles Wrapped in a 2D Carbon Envelope: Improved Low‐Temperature Oxygen Transfer and Oxidation Activity 下载免费PDF全文
Dr. Eleonora Aneggi Dr. Veronica Rico‐Perez Prof. Carla de Leitenburg Prof. Stefano Maschio Dr. Lluís Soler Prof. Jordi Llorca Prof. Alessandro Trovarelli 《Angewandte Chemie (International ed. in English)》2015,54(47):14040-14043
Engineering the interface between different components of heterogeneous catalysts at nanometer level can radically alter their performances. This is particularly true for ceria‐based catalysts where the interactions are critical for obtaining materials with enhanced properties. Here we show that mechanical contact achieved by high‐energy milling of CeO2–ZrO2 powders and carbon soot results in the formation of a core of oxide particles wrapped in a thin carbon envelope. This 2D nanoscale carbon arrangement greatly increases the number and quality of contact points between the oxide and carbon. Consequently, the temperatures of activation and transfer of the oxygen in ceria are shifted to exceptionally low temperatures and the soot combustion rate is boosted. The study confirms the importance of the redox behavior of ceria‐zirconia particles in the mechanism of soot oxidation and shows that the organization of contact points at the nanoscale can significantly modify the reactivity resulting in unexpected properties and functionalities. 相似文献
97.
This paper presents a formulation and resolution of a two-stage stochastic linear programming model with recourse for sow
farms producing piglets. The proposed model considers a medium-term planning horizon and specifically allows optimal replacement
and schedule of purchases to be obtained for the first stage. This model takes into account sow herd dynamics, housing facilities,
reproduction management, herd size with initial and final inventory of sows and uncertain parameters such as litter size,
mortality and fertility rates. These last parameters are explicitly incorporated via a finite set of scenarios. The proposed
model is solved by using the algebraic modelling software OPL Studio from ILOG, in combination with the solver CPLEX to solve
the linear models resulting from different instances considered. The article also presents results obtained with previous
deterministic models assessing the suitability of the stochastic approach. Finally, the conclusions drawn from the study including
an outlook are presented.
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We present three different ways of getting an actually computable enumeration of Q
+ in the sense of being able to know exactly which rational occupies a given position and vice versa. The first enumeration is based on the Pierce expansion model for representing real numbers. The other two are based on regular continued fractions.The first and third authors were supported by UPF Grant, Support d'Iniciació a la Recerca, # F3087613. 相似文献