In the National Mycobacterium Reference Laboratory of the Israeli National Public Health Laboratory (hereafter referred to
as “the laboratory”), three methods are employed for the molecular epidemiology of Mycobacterium tuberculosis: IS6110 restriction fragment length polymorphism typing (RFLP typing), 43 spacer oligonucleotide typing (spoligotyping),
and 24 loci Mycobacterial Interspersed Repeating Unit—Variable Number of Tandem Repeats typing (MIRU-VNTR typing). In this
article, we describe the main practical aspects concerning quality assurance of these methods that are based on standardized,
internationally agreed upon conditions, including consensus reference strains and markers. All three methods were validated
by classical epidemiology (confirmed transmission) and clinical information. The laboratory has introduced a new 5 colors,
4 primer sets multiplex modification of the optimal 24-miru typing system that includes an easily produced in-house internal
standard for the high-throughput capillary electrophoresis system. Quantitative measurement of the internal standards yielded
statistics for measurement uncertainty that include the frequency distribution, mean, standard deviation, 95% confidence interval
and coefficient of variation. Use of the new internal standard developed in our laboratory allowed us to introduce the first
quantitative evaluation of the system performance of the AB3130xl capillary electrophoresis genetic analyzer for MIRU-VNTR
typing. The results are discussed in terms of expected accuracy and precision of MIRU-VNTR results, and possible implications
for forensic microsatellite typing which may be much more sensitive to the observed intra- and inter-plate variation. 相似文献
The way the arrangement of small conductors of ionic current on biological membranes regulates flux is an open physical question. We study this problem by a model of diffusion through a cluster of channels in an impermeable biological cell membrane. We show that the flux depends on the relative distance between the channels and show that moving two contiguous channels apart may increase the flux by nearly 50%. Brownian simulations in 2 and 3 dimensions agree with the theoretical results. 相似文献
Synthesis at the nanoscale has progressed at a very fast pace during the last decades. The main challenge today lies in precise localization to achieve efficient nanofabrication of devices. In the present work, we report on a novel method for the patterning of gold metallic nanoparticles into nanostructures on a silicon-on-insulator (SOI) wafer. The fabrication makes use of relatively accessible equipment, a scanning electron microscope (SEM), and wet chemical synthesis. The electron beam implants electrons into the insulating material, which further anchors the positively charged Au nanoparticles by electrostatic attraction. The novel fabrication method was applied to several substrates useful in microelectronics to add plasmonic particles. The resolution and surface density of the deposition were tuned, respectively, by the electron energy (acceleration voltage) and the dose of electronic irradiation. We easily achieved the smallest written feature of 68?±?18 nm on SOI, and the technique can be extended to any positively charged nanoparticles, while the resolution is in principle limited by the particle size distribution and the scattering of the electrons in the substrate.