Giant microwave absorption in fine powders of superconductors

Enhanced microwave absorption, larger than that in the normal state, is observed in fine grains of type-II superconductors (MgB$_2$ and K$_3$C$_{60}$) for magnetic fields as small as a few $\%$ of the upper critical field. The effect is predicted by the theory of vortex motion in type-II superconductors, however its direct observation has been elusive due to skin-depth limitations; conventional microwave absorption studies employ larger samples where the microwave magnetic field exclusion significantly lowers the absorption. We show that the enhancement is observable in grains smaller than the penetration depth. A quantitative analysis on K$_3$C$_{60}$ in the framework of the Coffey--Clem (CC) theory explains well the temperature dependence of the microwave absorption and also allows to determine the vortex pinning force constant

Ultrafast sensing of photoconductivity decay using microwave resonators

Microwave reflectance probed photoconductivity (or $\mu$-PCD) measurement represents a contactless and non-invasive method to characterize impurity content in semiconductors. Major drawbacks of the method include a difficult separation of reflectance due to dielectric and conduction effects and that the $\mu$-PCD signal is prohibitively weak for highly conducting samples. Both of these limitations could be tackled with the use of microwave resonators due to the well-known sensitivity of resonator parameters to minute changes in the material properties combined with a null measurement. A general misconception is that time resolution of resonator measurements is limited beyond their bandwidth by the readout electronics response time. While it is true for conventional resonator measurements, such as those employing a frequency sweep, we present a time-resolved resonator parameter readout method which overcomes these limitations and allows measurement of complex material parameters and to enhance $\mu$-PCD signals with the ultimate time resolution limit being the resonator time constant. This is achieved by detecting the transient response of microwave resonators on the timescale of a few 100 ns \emph{during} the $\mu$-PCD decay signal. The method employs a high-stability oscillator working with a fixed frequency which results in a stable and highly accurate measurement.Comment: 7 pages, 6 figures+Supplementary Material

Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine

In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown

Revising mtDNA haplotypes of the ancient Hungarian conquerors with next generation sequencing

As part of the effort to create a high resolution representative sequence database of the medieval Hungarian conquerors we have resequenced the entire mtDNA genome of 24 published ancient samples with Next Generation Sequencing, whose haplotypes had been previously determined with traditional PCR based methods. We show that PCR based methods are prone to erroneous haplotype or haplogroup determination due to ambiguous sequence reads, and many of the resequenced samples had been classified inaccurately. The SNaPshot method applied with published ancient DNA authenticity criteria is the most straightforward and cheapest PCR based approach for testing a large number of coding region SNP-s, which greatly facilitates correct haplogroup determination

Isolation and identification of Pyrenophora chaetomioides from winter oat in Hungary

The aim of this study was to identify a fungal pathogen that caused necrotic leaf spots in experimental plots of oat in two remote regions of Hungary, the Southern Great Plain and Central Transdanubia. Two monosporic isolates, one from each region, were subjected to morphological and molecular investigations, and their pathogenicity to oat, barley and wheat seedlings was tested by artifcial inoculations. Morphology of cultures and conidia matched well the description of genus Drechslera, the asexual stage of Pyrenophora. The natural host and higher pathogenicity of both isolates to oat than to barley and wheat suggested that the fungus represented the primarily oat pathogen P. chaetomioides. Although accurate species identifcation could not be achieved due to overlapping morphology and host range among the oat and barley pathogenic Pyrenophora spp., PCR amplifcation and direct sequencing of the ITS1–5.8S–ITS2 region of the nuclear ribosomal DNA revealed 100% identity amongst our isolates and several reference strains of P. chaetomioides, justifying the species identity of the fungus we found on oats. Our study also confrmed an earlier, symptom-based observation about the occurrence of Pyrenophora leaf blotch disease in experimental plots in Hungary, and is the frst to prove the presence of its causal agent, P. chaetomioides, based on isolation and accurate species identifcation

Host-switching events are not always the driver of speciation in social parasites: a case study in Temnothorax (Myrmoxenus) ants (Hymenoptera, Formicidae)

Abstract Host?parasite systems, including social parasites that exploit resources of the host colonies, are fascinating objects for evolutionary biologists mainly due to the dynamic and often rapid host?parasite coevolution. Host-switching events are believed to induce rapid speciation of parasitic species. The socially parasitic ant lineage Myrmoxenus, which corresponds to the monophyletic Temnothorax corsicus group, counts in total a dozen species. Most Myrmoxenus species utilize a single host species, but a few others, like Myrmoxenus ravouxi (André, 1896) and M.?gordiagini Ruzsky, 1902, are known to use multiple host taxa. Myrmoxenus zaleskyi (Sadil, 1953) was described as a putative congener of M.?ravouxi based on its distinct host selection. In this paper, we investigate the diversity of the widely distributed European lineages M.?ravouxi and M.?zaleskyi from multiple and complementary perspectives to understand whether the host preference exhibited by these two forms implies speciation. We integrated evidence from molecular genetics using mitochondrial CO I/CO II genes, including the tLeu-region, and multivariate analyses of morphometric data collected from workers and female sexuals (gynes). Although there is substantial regional host species specificity, results suggest that host switching did not result in phylogenetic or morphological divergence and that the central European M.?zaleskyi can be considered the junior synonym of M.?ravouxi. As the lineage Myrmoxenus has been the subject of considerable evolutionary research, these results are essential to achieve a more accurate picture of host?parasite systems in the future and further strengthen the justification of an integrative approach in studying similarly complex systems. We advise against describing new parasitic species based on host preference unless coupled with marked heritable phenotypic adaptations

Occurrence of barley pathogenic Pyrenophora species and their mating types in Hungary

Net blotch and leaf stripe caused by Pyrenophora teres and P. graminea, respectively, are two major foliar diseases of barley. These two species are able to infect wheat, too. The species composition of these pathogens was examined, for the first time, in four different regions of Hungary in 2006–2010. Altogether 204 isolates were obtained from 99 winter barley, 55 spring barley and 50 wheat leaf samples collected in commercial fields and experimental stations, and species assignment was carried out using species-specific PCR reactions. Most isolates belonged to P. teres f. teres (68%), 26% to P. teres f. maculata and only 6% of the isolates were assigned to P. graminea. Interestingly, all but one of the P. graminea isolates came from the western part of Hungary, while both forms of P. teres occurred in each region. The distribution of mating type genes was also examined in 144 isolates. The overall ratio of MAT1 and MAT2 genes in P. graminea, P. teres f. maculata and P. teres f. teres was 5:3, and close to 2:1 and 1:1, respectively. Both MAT1 and MAT2 isolates of each fungal species/form were distributed in almost all regions over several years, indicating a high potential for sexual outcrossing within local populations of these pathogens. Our survey may be helpful to determine priorities in disease resistance breeding programs. Further studies are in progress to examine the population structure of the most abundant pathogen P. teres f. teres