Nonlinear resonance interaction of ultrasonic waves under applied stress

Copyright 1984 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 56(1), 235-237, 1984 and may be found at http://dx.doi.org/10.1063/1.33375

DNA-viivakoodaus elintarvikkeiden aitoustutkimuksissa

Opinnäytetyön tarkoituksena oli ottaa käyttöön ja validoida DNA-viivakoodaus-menetelmä Elintarviketurvallisuusvirasto Eviralle. DNA-viivakoodaus oli alun perin ekologisiin tutkimuksiin kehitelty menetelmä, mutta pian siitä huomattiin olevan hyötyä myös muilla tutkimusalueilla, kuten elintarvikkeiden aitoustutkimuksissa. Elintarvikepetoksia ja etenkin mereneläviin kohdistuvia väärennöksiä paljastuu yhä enemmän maailmalla. Suomessa näitä väärennöksiä ei ole kovinkaan paljoa tutkittu aikaisemmin. DNA-viivakoodaus-menetelmä perustuu siihen, että genomista on valittu alue, jossa lajin sisällä emäsjärjestys vaihtelee mahdollisimman vähän ja eri lajien välillä suuresti. Lajit voidaan erottaa toisistaan viivakoodialueen sekvenssien perusteella. Eläinlajeilla käytetään usein mitokondriaalisen DNA:n sytokromi c oksidaasi 1 -geeniä (CO1) ja kasveilla kloroplastin maturaasi K (matK)- ja ribuloosi bisfosfaatti karboksylaasi iso alayksikkö (rbcL) -geenejä. Opinnäytetyön laboratorio-osuus suoritettiin pääosin Yhdysvaltain elintarvike- ja lääkevirasto FDA:n laatiman työohjeen mukaisesti. Kalanäytteestä eristettiin DNA, josta monistettiin PCR:llä tietty nukleotidijakso. PCR-tuote puhdistettiin ja sekvensoitiin. Sekvensoinnin tulokset käsiteltiin bioinformatiikan työkaluin ja saatuja sekvenssejä verrattiin sekvenssitietokantoihin, jolloin saatiin selville näytteen kalalaji. Menetelmän käyttöönotto onnistui hyvin. DNA-eristys onnistui, mikäli näytemäärä ei ollut liian suuri. Erilaiset matriisit, kuten savustettu tai suolattu kala, eivät aiheuttaneet ongelmia. Poikkeuksena olivat ainoastaan liian prosessoidut tuotteet, kuten öljyyn säilötty purkkikala. Työssä käytetyt alukkeet toimivat usealle lajille, ja lajintunnistus onnistui vähintään sukutasolle asti. Alustavien tutkimusten perusteella samat alukkeet ja menetelmä soveltuvat myös eläinlajien määritykseen.The purpose of this Bachelor’s thesis was to implement and validate a DNA barcoding method for Finnish Food Safety Authority Evira. DNA barcoding method was originally developed for ecological studies, but soon it was found to be useful in other areas of research as well, such as food authenticity studies. Increasing amount of food frauds, especially seafood forgeries have been found around the world. In Finland, these forgeries have not been studied intensively until recently. DNA barcoding method is based on analysis of a selected area in the genome. The selected genome area should have as little sequence variety as possible within a species and as much as possible between different species. Species can be identified by the sequences of the barcode region. The cytochrome c oxidase subunit 1 gene (CO1) from mitochondrial DNA is often used with animal identification, and maturase K (matK) and ribulose bisphosphate carboxylase large chain (rbcL) genes from the chloroplast are used when researching plants. The laboratory work in this thesis was carried out mainly in accordance with the standard operating procedure made by the U.S. Food and Drug Administration FDA. The DNA was extracted from the fish sample, and a specific nucleotide sequence was amplified from the DNA. The PCR product was purified and sequenced. The results of the sequencing were processed with bioinformatics tools, and the gained sequences were compared to sequence databases to identify the species of the fish sample. The implementation of this method was successful. DNA extraction succeeded if the sample was not too large. Different matrices, such as smoked or salted fish, did not cause problems. The only exceptions were too far processed products, such as fish canned in oil. The primers used in this thesis were functional in many species and the identification of the species was successful until the family level at least. On the bases of the preliminary studies, the same primers and method are also suitable for the identification of several animal species

Resonance EMAT system for acoustoelastic stress measurement in sheet metals

Copyright 1993 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 64(11), 3198-3205, 1993 and may be found at http://dx.doi.org/10.1063/1.114432

Glasslike vs. crystalline thermal conductivity in carrier-tuned Ba8Ga16X30 clathrates (X = Ge, Sn)

The present controversy over the origin of glasslike thermal conductivity observed in certain crystalline materials is addressed by studies on single-crystal x-ray diffraction, thermal conductivity k(T) and specific heat Cp(T) of carrier-tuned Ba8Ga16X30 (X = Ge, Sn) clathrates. These crystals show radically different low-temperature k(T) behaviors depending on whether their charge carriers are electrons or holes, displaying the usual crystalline peak in the former case and an anomalous glasslike plateau in the latter. In contrast, Cp(T) above 4 K and the general structural properties are essentially insensitive to carrier tuning. We analyze these combined results within the framework of a Tunneling/Resonant/Rayleigh scatterings model, and conclude that the evolution from crystalline to glasslike k(T) is accompanied by an increase both in the effective density of tunnelling states and in the resonant scattering level, while neither one of these contributions can solely account for the observed changes in the full temperature range. This suggests that the most relevant factor which determines crystalline or glasslike behavior is the coupling strength between the guest vibrational modes and the frameworks with different charge carriers.Comment: 8 pages, 4 figures, 4 tables, submitted to Phys. Rev.

Preliminary examination of the Yamato-86032 lunar meteorite: II. Major and trace element chemistry

The chemical composition of the new lunar meteorite Yamato-86032 has been studied by several laboratories in a consortium study. A preliminary report on the first analytical results from seven laboratories is given in this paper. The meteorite, which is the largest lunar meteorite recovered so far, is more heavily shocked than the other five lunar meteorites, which makes it difficult to classify the rock exactly. Although it may be classified as an anorthositic breccia the trace element composition of Y-86032 is somewhat different from the composition of the other known lunar meteorites. The major element chemistry of Y-86032 is similar to the other lunar meteorites, except for the iron content, which is lower by a factor of about 1. 4. Since the magnesium abundance is nearly identical there is a disparity in the mg ratio. The REE abundances in Y-86032 are very low and comparable to Y-82192/3. There is no evidence of any KREEP component. The abundances of several lithophile and incompatible elements are lower in Y-86032 than in the other lunar meteorites. The siderophile element contents are low and vary between individual chips. Sc, Cr, Mn, and Co have significantly lower abundances than in Y-82192/3. The chemical investigations demonstrate that Y-86032 is a new and important sample from the lunar highlands

Goldstone Mode Relaxation in a Quantum Hall Ferromagnet due to Hyperfine Interaction with Nuclei

Spin relaxation in quantum Hall ferromagnet regimes is studied. As the initial non-equilibrium state, a coherent deviation of the spin system from the ${\vec B}$ direction is considered and the breakdown of this Goldstone-mode state due to hyperfine coupling to nuclei is analyzed. The relaxation occurring non-exponentially with time is studied in terms of annihilation processes in the "Goldstone condensate" formed by "zero spin excitons". The relaxation rate is calculated analytically even if the initial deviation is not small. This relaxation channel competes with the relaxation mechanisms due to spin-orbit coupling, and at strong magnetic fields it becomes dominating.Comment: 8 page