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71.
72.
Cafer Cakal Jerome P. Ferrance James P. Landers Perihan Caglar 《Analytica chimica acta》2011,(1):3012
A novel solid phase extraction microchip with a boronic acid functional affinity monolithic disc was developed in this work. Vinyl phenylboronic acid–ethylene glycol dimethacrylate co-polymer monoliths, which have pore sizes up to 20 μm, were investigated for extraction of catecholamines using adsorption and desorption studies in a batch system. Desorption yields of greater than 90% were achieved for catecholamines at pH 3 and below. Monolithic discs were then formed in chambers in borofloat glass microfluidic chips using in situ UV polymerization. Adsorption on the monolithic discs was performed via electrokinetic flow, with catecholamines determined via laser-induced native fluorescence (LINF) detection following electrokinetic elution. Microchips containing the boronic acid functional polymer discs worked well for extraction of catecholamines, providing greater than 100 fold concentration enrichment. This study demonstrated that a solid phase extraction microchip, containing an easily prepared monolith disc, will be useful for boronate affinity extraction of cis-diol containing compounds. 相似文献
73.
A graph G of order n is called t‐edge‐balanced if G satisfies the property that there exists a positive λ for which every graph of order n and size t is contained in exactly λ distinct subgraphs of isomorphic to G. We call λ the index of G. In this article, we obtain new infinite families of 2‐edge‐balanced graphs. 相似文献
74.
Numerical solution of the Korteweg–de Vries equation is obtained using space-splitting technique and the differential quadrature method based on cosine expansion (CDQM). The details of the CDQM and its implementation to the KdV equation are given. Three test problems are studied to demonstrate the accuracy and efficiency of the proposed method. Accuracy and efficiency are discussed by computing the numerical conserved laws and L2, L∞ error norms. 相似文献
75.
In this paper we investigate discrete spectrum of the non-selfadjoint matrix Sturm-Liouville operator L generated in L2(R+,S) by the differential expression
76.
Salhi M Hideur A Chartier T Brunel M Martel G Ozkul C Sanchez F 《Optics letters》2002,27(15):1294-1296
We have designed and performed an experiment that permitted direct observation of Brillouin backscattering in an Yb-doped double-clad fiber laser. Fifteen Brillouin-shifted frequencies were observed for the first time to our knowledge. We clearly demonstrate that stimulated Brillouin scattering is directly responsible for both fast transient dynamics of the laser and reduction of the laser's pulse width. 相似文献
77.
Systematic Investigation of the Effect of Polymerization Routes on the Gas‐Sorption Properties of Nanoporous Azobenzene Polymers
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Dr. Onur Buyukcakir Sang Hyun Je Dr. Joonho Park Dr. Hasmukh A. Patel Prof. Yousung Jung Prof. Cafer T. Yavuz Prof. Ali Coskun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15320-15327
Functional‐group‐oriented polymerization strategies have contributed significantly to the initial development of porous polymers and have led to the utilization of several well‐known organic transformations in the synthesis of these polymers. Because there are multiple polymerization routes that can be used to introduce the same chemical functionality, it is very important to demonstrate the effect of different polymerization routes on the gas‐sorption properties of these chemically similar polymers. Herein, we have studied the rich chemistry of azobenzenes and synthesized four chemically similar nanoporous azobenzene polymers (NABs) with surface areas of up to 1021 m2 g?1. The polymerization routes have a significant impact on the pore‐size distributions of the NABs, which directly affects the temperature dependence of the CO2/N2 selectivity. A pore‐width maximum of 6–8 Å, narrow pore‐size distribution, and small particle size (20–30 nm) were very critical for high CO2/N2 selectivity and N2 phobicity, which is associated with azo linkages and realized at warm temperatures. Our findings collectively suggest that an investigation of different polymerization routes for the same chemical functionalization is critical to understand fully the combined effect of textural properties, local environment, and chemical functionalization on the gas‐sorption properties of nanoporous polymers. 相似文献
78.
Nick Mitsios Mohamad Saka Jerzy Krupinski Roberta Pennucci Coral Sanfeliu Qiuyu Wang Francisco Rubio John Gaffney Pat Kumar Shant Kumar Matthew Sullivan Mark Slevin 《BMC neuroscience》2007,8(1):1-14
Background
Our goal was to examine the spatiotemporal integration of tactile information in the hand representation of human primary somatosensory cortex (anterior parietal somatosensory areas 3b and 1), secondary somatosensory cortex (S2), and the parietal ventral area (PV), using high-resolution whole-head magnetoencephalography (MEG). To examine representational overlap and adaptation in bilateral somatosensory cortices, we used an oddball paradigm to characterize the representation of the index finger (D2; deviant stimulus) as a function of the location of the standard stimulus in both right- and left-handed subjects.Results
We found that responses to deviant stimuli presented in the context of standard stimuli with an interstimulus interval (ISI) of 0.33s were significantly and bilaterally attenuated compared to deviant stimulation alone in S2/PV, but not in anterior parietal cortex. This attenuation was dependent upon the distance between the deviant and standard stimuli: greater attenuation was found when the standard was immediately adjacent to the deviant (D3 and D2 respectively), with attenuation decreasing for non-adjacent fingers (D4 and opposite D2). We also found that cutaneous mechanical stimulation consistently elicited not only a strong early contralateral cortical response but also a weak ipsilateral response in anterior parietal cortex. This ipsilateral response appeared an average of 10.7 ± 6.1 ms later than the early contralateral response. In addition, no hemispheric differences either in response amplitude, response latencies or oddball responses were found, independent of handedness.Conclusion
Our findings are consistent with the large receptive fields and long neuronal recovery cycles that have been described in S2/PV, and suggest that this expression of spatiotemporal integration underlies the complex functions associated with this region. The early ipsilateral response suggests that anterior parietal fields also receive tactile input from the ipsilateral hand. The lack of a hemispheric difference in responses to digit stimulation supports a lack of any functional asymmetry in human somatosensory cortex. 相似文献79.
Vidak Raičević Niko Radulović Ljiljana Jovanović Marko Rodić Ivana Kuzminac Dimitar Jakimov Tanja Wrodnigg Tim-Oliver Knedel Christoph Janiak Marija Sakač 《应用有机金属化学》2020,34(10):e5889
Conjugates of ferrocene with steroidal estrogens as selective antiproliferative agents against hormone-dependent breast cancer cells are believed to be limited by the inherent estrogenicity of the conjugates. Motivated by a significant cytotoxicity of the ester of ferrocenecarboxylic acid and the phenolic group of estradiol toward such a cell line, we decided to explore other a -ring-tethered ferrocene–estra-1,3,5(10)-triene conjugates; in this study, ferrocenylmethylation of estradiol and estrone with (ferrocenylmethyl)trimethylammonium iodide in the presence of potassium carbonate yielded five new compounds ( 1 – 5 ). In dimethylformamide, only O-alkylated products formed ( 1 and 3 ), while a mixture of O- and C-alkylated products was obtained when methanol was used ( 2 , 4 , and 5 in addition to 1 and 3 ). All compounds were characterized using 1D and 2D NMR, IR, UV–Vis, and high-resolution mass spectrometry. Two of the conjugates, a 3-O- and a 4-C-alkylated derivative of estrone ( 3 and 4 , respectively), were also analyzed using single-crystal X-ray diffraction. A cyclic voltammetric investigation of the electrochemical properties of 1 – 5 was performed. While some of the compounds were shown to have a slight-to-moderate antiproliferative activity against at least one of the six tested human tumor cell lines and were nontoxic to (the noncancerous) fetal human fibroblasts, compound 2 (4-(ferrocenylmethyl)estra-1,3,5(10)-triene-3,17β-diol) with an IC50 value of 0.34 μM was found to be more active against the hormone-dependent breast cancer cell line MCF-7 than doxorubicin. These results suggest that a -ring substitution of steroidal estrogens is a plausible strategy for preparing other ferrocene–steroid conjugates acting against tumor cells. 相似文献
80.
Dizman Serdar Akdemir Tolga Yeşilkanat Cafer Mert Nevruzoglu Vagif Bal Esra Keser Recep 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(6):2533-2544
Journal of Radioanalytical and Nuclear Chemistry - In this study, natural and artificial radioactivity concentrations in sediment samples taken from ?av?at Black Lake located on the... 相似文献