排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
2.
Nandy JP Rakic B Sarma BV Babu N Lefrance M Enright GD Leek DM Daniel K Sabourin LA Arya P 《Organic letters》2008,10(6):1143-1146
We report here a practical, enantioselective synthesis of benzofuran-derived, cyclic trans-beta-amino acid scaffold. In two cases, tricyclic derivatives having six- and eight-membered unsaturated lactams were obtained from this versatile scaffold. To explore the biological applications, these compounds were subjected to cell-based assays, using NIH3T3 mouse cells to examine their potency as cell motility inhibitors and identified 18 as a potent cell motility inhibitor (IC50 approximately 40 microM in chamber cell migration assay). 相似文献
3.
A microfluidic device (the HistoFlex) designed to perform and monitor molecular biological assays under dynamic flow conditions on microscope slide-substrates, with special emphasis on analyzing histological tissue sections, is presented. Microscope slides were reversibly sealed onto a cast polydimethylsiloxane (PDMS) insert, patterned with distribution channels and reaction chambers. Topology optimization was used to design reaction chambers with uniform flow conditions. The HistoFlex provided uniform hybridization conditions, across the reaction chamber, as determined by hybridization to microscope slides of spotted DNA microarrays when applying probe concentrations generally used in in situ hybridization (ISH) assays. The HistoFlex's novel ability in online monitoring of an in situ hybridization assay was demonstrated using direct fluorescent detection of hybridization to 18S rRNA. Tissue sections were not visually damaged during assaying, which enabled adapting a complete ISH assay for detection of microRNAs (miRNA). The effects of flow based incubations on hybridization, antibody incubation and Tyramide Signal Amplification (TSA) steps were investigated upon adapting the ISH assay for performing in the HistoFlex. The hybridization step was significantly enhanced using flow based incubations due to improved hybridization efficiency. The HistoFlex device enabled a fast miRNA ISH assay (3 hours) which provided higher hybridization signal intensity compared to using conventional techniques (5 h 40 min). We further demonstrate that the improved hybridization efficiency using the HistoFlex permits more complex assays e.g. those comprising sequential hybridization and detection of two miRNAs to be performed with significantly increased sensitivity. The HistoFlex provides a new histological analysis platform that will allow multiple and sequential assays to be performed under their individual optimum assay conditions. Images can subsequently be recorded either in combination or sequentially through the ability of the HistoFlex to monitor assays without disassembly. 相似文献
4.
Sun Y Perch-Nielsen I Dufva M Sabourin D Bang DD Høgberg J Wolff A 《Analytical and bioanalytical chemistry》2012,402(2):741-748
DNA microarrays have become one of the most powerful tools in the field of genomics and medical diagnosis. Recently, there
has been increased interest in combining microfluidics with microarrays since this approach offers advantages in terms of
portability, reduced analysis time, low consumption of reagents, and increased system integration. Polymers are widely used
for microfluidic systems, but fabrication of microarrays on such materials often requires complicated chemical surface modifications,
which hinders the integration of microarrays into microfluidic systems. In this paper, we demonstrate that simple UV irradiation
can be used to directly immobilize poly(T)poly(C)-tagged DNA oligonucleotide probes on many different types of plastics without
any surface modification. On average, five- and fourfold improvement in immobilization and hybridization efficiency have been
achieved compared to surface-modified slides with aminated DNA probes. Moreover, the TC tag only costs 30% of the commonly
used amino group modifications. Using this microarray fabrication technique, a portable cyclic olefin copolymer biochip containing
eight individually addressable microfluidic channels was developed and used for rapid and parallel identification of Avian
Influenza Virus by DNA hybridization. The one-step, cost-effective DNA-linking method on non-modified polymers significantly
simplifies microarray fabrication procedures and permits great flexibility to plastic material selection, thus making it convenient
to integrate microarrays into plastic microfluidic systems. 相似文献
5.
Anatoli Onopchenko Edward T. Sabourin David A. Danner 《Journal of mass spectrometry : JMS》1985,20(8):505-510
The mass spectra of tetra(alkyl)silanes having one short and three long alkyl groups were recorded (C20? C32). These silanes did not give molecular ions, and the dominant course of fragmentation involved the loss of alkyl groups, followed by elimination of alkenes. The loss of alkyl groups, followed by elimination of alkenes. The loss of alkyl groups followed the sequence iso-Pr>Et, Pr,… C14H29» Me. With alkyl groups longer than hexyl, a rearrangement was observed in which n-alkanes were eliminated from the base ion. When the alkyl group was hexyl, the alkane eliminated was methane; when the alkyl group was heptyl, ethane was expelled; with octyl, it was propane; and with decyl, n-pentane was expelled. Deuterium labeling showed that at least two modes of rearrangement were occurring. 相似文献
6.
Carol L. K. Sabourin Abbie G. Freeman Donna F. Kusewitt Ronald D. Ley 《Photochemistry and photobiology》1992,55(3):417-424
Chronic exposure of the gray, short-tailed oppossum, Monodelphis domestica to ultraviolet radiation (UVR) induces mesenchymal tumors of the cornea. High molecular weight DNA samples from 6 UVR-induced corneal tumors were assayed for their ability to transform NIH 3T3 cells to tumorigenicity. NIH 3T3 cells transfected with DNA from 5 of the corneal tumors produced 14 tumors in nude mice. Cell lines were established from these tumors. DNA from 13 of 14 tumor cell lines contained repetitive opossum DNA sequences. Southern blot analysis revealed that DNA from 3 of 4 cell lines derived from tumorigenic NIH 3T3 cells transfected with DNA from a single oppossum tumor contained opossum Ki-ras oncogene sequences in addition to the murine Ki-ras gene. Northern blot analysis of mRNA from a mouse tumor cell line containing opossum Ki-ras gene sequences showed mRNA species identical in size to opossum Ki-ras mRNA, as well as murine Ki-ras mRNA species. These results suggest that an activated Ki-ras oncogene was present in one of the original opossum corneal tumors tested. Thus, activation of Ki-ras may play a role in the development of UVR-induced corneal tumors in Monodelphis domestica. Further characterization of ras oncogenes in these opossum tumors may provide information on the molecular mechanisms by which UVR induces corneal tumors in this species. 相似文献
7.
Arto Heiskanen Vasile Coman Natalie Kostesha David Sabourin Nick Haslett Keith Baronian Lo Gorton Martin Dufva Jenny Emnéus 《Analytical and bioanalytical chemistry》2013,405(11):3847-3858
Conventionally, microbial bioelectrochemical assays have been conducted using immobilized cells on an electrode that is placed in an electrochemical batch cell. In this paper, we describe a developed microfluidic platform with integrated microelectrode arrays for automated bioelectrochemical assays utilizing a new double mediator system to map redox metabolism and screen for genetic modifications in Saccharomyces cerevisiae cells. The function of this new double mediator system based on menadione and osmium redox polymer (PVI-Os) is demonstrated. “Wiring” of S. cerevisiae cells using PVI-Os shows a significant improvement of bioelectrochemical monitoring in a microfluidic environment and functions as an effective immobilization matrix for cells that are not strongly adherent. The function of the developed microfluidic platform is demonstrated using two strains of S. cerevisiae, ENY.WA and its deletion mutant EBY44, which lacks the enzyme phosphoglucose isomerase. The cellular responses to introduced glucose and fructose were recorded for the two S. cerevisiae strains, and the obtained results are compared with previously published work when using an electrochemical batch cell, indicating that microfluidic bioelectrochemical assays employing the menadione–PVI-Os double mediator system provides an effective means to conduct automated microbial assays. Figure
Microfluidic platform for bioelectrochemical assays using osmium redox polymer “wired” living yeast cells 相似文献
8.
9.
10.
Sabourin P Gottlieb H Pollack GS 《The Journal of the Acoustical Society of America》2008,123(5):2910-2917
Signal processing in the auditory interneuron Omega Neuron 1 (ON1) of the cricket Teleogryllus oceanicus was compared at high- and low-carrier frequencies in three different experimental paradigms. First, integration time, which corresponds to the time it takes for a neuron to reach threshold when stimulated at the minimum effective intensity, was found to be significantly shorter at high-carrier frequency than at low-carrier frequency. Second, phase locking to sinusoidally amplitude modulated signals was more efficient at high frequency, especially at high modulation rates and low modulation depths. Finally, we examined the efficiency with which ON1 detects gaps in a constant tone. As reflected by the decrease in firing rate in the vicinity of the gap, ON1 is better at detecting gaps at low-carrier frequency. Following a gap, firing rate increases beyond the pre-gap level. This "rebound" phenomenon is similar for low- and high-carrier frequencies. 相似文献