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Ionization of helium by potassium positive ions

A continuation of previous attempts to ionize gases by positive ions has been extended to helium using potassium positive ions as high as 750 volts accelerating potential. At pressures between 0.01 and 0.1 mm there is definite evidence of ionization of helium above 150 or 200 volts accelerating potential. The effect is much smaller than in the gases previously reported, but it may be distinguished from the secondary emission of electrons from the metal parts under action of the positive ions. Great difficulty was encountered in changes of intensity of ionization due to impurities in the helium. Some of the uncertainties in previous work have been removed by changing the relative positions of electrodes

Ionization of argon, neon and helium by various alkali ions

Caesium, rubidium, potassium, and sodium positive ions from Kunsman catalyst sources, and lithium ions from spodumene have been used to produce ionization in helium, neon, and argon. In most cases the ionization sets in between 100-150 volts and increases linearly to 750 volts, the highest potential used. Maximum ionization was produced in each gas by the alkali ion closest to it in atomic number

Increasing the density of nanomedicines improves their ultrasound-mediated delivery to tumours

AbstractNanomedicines have provided fresh impetus in the fight against cancer due to their selectivity and power. However, these agents are limited when delivered intravenously due to their rapid clearance from the bloodstream and poor passage from the bloodstream into target tumours. Here we describe a novel stealthing strategy which addresses both these limitations and thereby demonstrate that both the passive and mechanically-mediated tumour accumulation of the model nanomedicine adenovirus (Ad) can be substantially enhanced. In our strategy gold nanoparticles were thoroughly modified with 2kDa polyethyleneglycol (PEG) and then linked to Ad via a single reduction-cleavable 5kDa PEG. The resulting Ad–gold–PEG construct was compared to non-modified Ad or conventionally stealthed Ad–poly[N-(2-hydroxypropyl)methacrylamide] (Ad–PHPMA). Notably, although Ad–gold–PEG was of similar size and surface charge to Ad–PHPMA the increase in density, resulting from the inclusion of the gold nanoparticles, provided a substantial enhancement of ultrasound-mediated transport. In an in vitro tumour mimicking phantom, the level and distance of Ad–gold–PEG transport was shown to be substantially greater than achieved with Ad–PHPMA. In in vivo studies 0.1% of an unmodified Ad dose was shown to accumulate in tumours, whereas over 12% of the injected dose was recovered from the tumours of mice treated with Ad–gold–PEG and ultrasound. Ultimately, a significant increase in anti-tumour efficacy resulted from this strategy. This stealthing and density-increasing technology could ultimately enhance clinical utility of intravenously delivered nanoscale medicines including viruses, liposomes and antibodies

Mapping a candidate gene (MdMYB10) for red flesh and foliage colour in apple

<p>Abstract</p> <p>Background</p> <p>Integrating plant genomics and classical breeding is a challenge for both plant breeders and molecular biologists. Marker-assisted selection (MAS) is a tool that can be used to accelerate the development of novel apple varieties such as cultivars that have fruit with anthocyanin through to the core. In addition, determining the inheritance of novel alleles, such as the one responsible for red flesh, adds to our understanding of allelic variation. Our goal was to map candidate anthocyanin biosynthetic and regulatory genes in a population segregating for the red flesh phenotypes.</p> <p>Results</p> <p>We have identified the <it>Rni </it>locus, a major genetic determinant of the red foliage and red colour in the core of apple fruit. In a population segregating for the red flesh and foliage phenotype we have determined the inheritance of the <it>Rni </it>locus and DNA polymorphisms of candidate anthocyanin biosynthetic and regulatory genes. Simple Sequence Repeats (SSRs) and Single Nucleotide Polymorphisms (SNPs) in the candidate genes were also located on an apple genetic map. We have shown that the MdMYB10 gene co-segregates with the <it>Rni </it>locus and is on Linkage Group (LG) 09 of the apple genome.</p> <p>Conclusion</p> <p>We have performed candidate gene mapping in a fruit tree crop and have provided genetic evidence that red colouration in the fruit core as well as red foliage are both controlled by a single locus named <it>Rni</it>. We have shown that the transcription factor MdMYB10 may be the gene underlying <it>Rni </it>as there were no recombinants between the marker for this gene and the red phenotype in a population of 516 individuals. Associating markers derived from candidate genes with a desirable phenotypic trait has demonstrated the application of genomic tools in a breeding programme of a horticultural crop species.</p

Differences in the distribution of F-actin in outer hair cells along the organ of Corti

There is evidence of differences in the structure, innervation and physiological responses between outer hair cells (OHCs) of the basal and apical turns of the mammalian cochlea. In this study we have used rhodamine-labelled phalloidin to investigate the differential distribution of F-actin in OHCs along the organ of Corti of the guinea pig. Isolated OHCs and surface preparations and cryosections of the organ of Corti were studied. F-actin was observed in stereocilia and the cuticular plate of all OHCs. In addition, some OHCs had a network of F-actin extending from the cuticular plate towards the nucleus. This infracuticular network was observed in most OHCs of the apical cochlear turns but was not seen in any OHCs of the basal turn. These microstructural differences between OHCs of the base and apex could be related to differences in OHC function between the apical and basal portions of the cochlea.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26926/1/0000492.pd