1,530 research outputs found

    Modelling mineral dust using stereophotogrammetry

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    Real, three-dimensional shape of a dust particle is derived from a pair of scanning-electron microscope images by means of stereophotogrammetry. The resulting shape is discretized, and preliminary discrete-dipole-approximation computations for the single dust particle reveal that scattering by such an irregular shape differs notably from scattering by a sphere or a Gaussian random sphere which both are frequently used shape models for dust particles

    Vuosina 2008–2016 OYS:ssa kuolleiden lasten soveltuvuus elinluovuttajiksi

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    TiivistelmĂ€. Suomessa lapsikuolleisuus on nykyÀÀn pienempiĂ€ maailman tasolla. Lasten kuolleisuus on Suomessa pienentynyt koko viime vuosisadan ajan. Lain mukaan ihminen on kuollut, kun kaikki hĂ€nen aivotoimintonsa ovat pysyvĂ€sti loppuneet. Kuolema voidaan todeta sydĂ€men vielĂ€ sykkiessĂ€, kun tutkittaessa aivoperĂ€iset vasteet puuttuvat ja todetaan ettĂ€ hengityskeskuksen toiminta on loppunut. Aivokuoleman mÀÀritelmĂ€ on sama lapsilla ja aikuisilla. Lapsilla aivokuolemat ovat harvinaisia, jopa lasten teho-osastoilla, jonka takia jokainen aivokuollut tulisi tunnistaa. Elinsiirrot ovat kustannusvaikutteisia hoitomuotoja, jotka usein pelastavat potilaan hengen vaikeimmissa maksan, sydĂ€men ja keuhkojen sairauksissa. Lapset eivĂ€t sÀÀsty elinsiirtojonoissa olemiselta ja lista elinsiirtoa odottavista lapsista on kasvanut. Lapsipotilaiden mÀÀrĂ€ elinluovuttajia sen sijaan on monien vuosien ajan pysynyt samalla tasolla. TĂ€mĂ€n tutkimuksen avulla pyrimme selvittĂ€mÀÀn, toimiiko Pohjois-Pohjanmaan sairaanhoitopiirin alueella lapsipotilaiden kohdalla elinsiirtokandidaattien tunnistaminen ja hoito asetusten mukaisesti. Kartoitimme mahdollisia ongelmakohtia luovuttajakandidaattien tunnistamisessa. TĂ€mĂ€ tutkimus on takautuva rekisteritutkimus. Tutkimukseen otimme mukaan kaikki vuosina 2008–2016 OYS:ssa kuolleet lapset (alle 18-vuotiaat). Tutkimustiedot kerĂ€ttiin ESKO-potilasjĂ€rjestelmĂ€stĂ€ ja tutkimuksessa kĂ€ytettiin aineiston analyysiin SPSS-ohjelmaa. Tutkimustulosten perusteella aivokuolleiksi luokiteltiin 10 potilasta (5,7%). NĂ€istĂ€ potilaista elinluovuttajana toimi yhteensĂ€ viisi potilasta. Kahden potilaan kohdalla aivokuolemaa ei tunnistettu ja huoltajien mielipidettĂ€ elinluovutuksesta ei kysytty. LisĂ€ksi huoltajien kielteinen mielipide elinluovutuksesta esti kahden potilaan kohdalla aivokuolemadiagnoosin lopullisen tekemisen. Lasten yleisimmĂ€t kuolinsyyt OYS:ssa nĂ€inĂ€ vuosina olivat synnynnĂ€iset rakennepoikkeavuudet ja onkologiset sairaudet

    Single scattering by realistic, inhomogeneous mineral dust particles with stereogrammetric shapes

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    Light scattering by single, inhomogeneous mineral dust particles was simulated based on shapes and compositions derived directly from measurements of real dust particles instead of using a mathematical shape model. We demonstrate the use of the stereogrammetric shape retrieval method in the context of single-scattering modelling of mineral dust for four different dust types – all of them inhomogeneous – ranging from compact, equidimensional shapes to very elongated and aggregate shapes. The three-dimensional particle shapes were derived from stereo pairs of scanning-electron microscope images, and inhomogeneous composition was determined by mineralogical interpretation of localized elemental information based on energy-dispersive spectroscopy. Scattering computations were performed for particles of equal-volume diameters, from 0.08 ÎŒm up to 2.8 ÎŒm at 550 nm wavelength, using the discrete-dipole approximation. Particle-to-particle variation in scattering by mineral dust was found to be quite considerable and was not well reproduced by simplified shapes of homogeneous spheres, spheroids, or Gaussian random spheres. Effective-medium approximation results revealed that particle inhomogeneity should be accounted for even for small amounts of absorbing media (here up to 2% of the volume), especially when considering scattering by inhomogeneous particles at size parameters 3<<i>x</i><8. When integrated over a log-normal size distribution, the linear depolarization ratio and single-scattering albedo were also found to be sensitive to inhomogeneity. The methodology applied is work-intensive and the light-scattering method used quite limited in terms of size parameter coverage. It would therefore be desirable to find a sufficiently accurate but simpler approach with fewer limitations for single-scattering modelling of dust. For validation of such a method, the approach presented here could be used for producing reference data when applied to a suitable set of target particles

    Adipose tissue NAD(+)-homeostasis, sirtuins and poly(ADP-ribose) polymerases - important players in mitochondrial metabolism and metabolic health

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    Obesity, a chronic state of energy overload, is characterized by adipose tissue dysfunction that is considered to be the major driver for obesity associated metabolic complications. The reasons for adipose tissue dysfunction are incompletely understood, but one potential contributing factor is adipose tissue mitochondrial dysfunction. Derangements of adipose tissue mitochondrial biogenesis and pathways associate with obesity and metabolic diseases. Mitochondria are central organelles in energy metabolism through their role in energy derivation through catabolic oxidative reactions. The mitochondrial processes are dependent on the proper NAD(+)/NADH redox balance and NAD+ is essential for reactions catalyzed by the key regulators of mitochondrial metabolism, sirtuins (SIRTs) and poly(ADP-ribose) polymerases (PARPs). Notably, obesity is associated with disturbed adipose tissue NAD(+) homeostasis and the balance of SIRT and PARP activities. In this review we aim to summarize existing literature on the maintenance of intracellular NAD(+) pools and the function of SIRTs and PARPs in adipose tissue during normal and obese conditions, with the purpose of comprehending their potential role in mitochondrial derangements and obesity associated metabolic complications. Understanding the molecular mechanisms that are the root cause of the adipose tissue mitochondrial derangements is crucial for developing new effective strategies to reverse obesity associated metabolic complications.Peer reviewe

    Water and Blood Repellent Flexible Tubes

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    A top-down scalable method to produce flexible water and blood repellent tubes is introduced. The method is based on replication of overhanging nanostructures from an aluminum tube template to polydimethylsiloxane (PDMS) via atomic layer deposition (ALD) assisted sacrificial etching. The nanostructured PDMS/titania tubes are superhydrophobic with water contact angles 163 +/- 1 degrees (advancing) and 157 +/- 1 degrees (receding) without any further coating. Droplets are able to slide through a 4 mm (inner diameter) tube with low sliding angles of less than 10 degrees for a 35 mu L droplet. The superhydrophobic tube shows up to 5,000 times increase in acceleration of a sliding droplet compared to a control tube depending on the inclination angle. Compared to a free falling droplet, the superhydrophobic tube reduced the acceleration by only 38.55%, as compared to a 99.99% reduction for a control tube. The superhydrophobic tubes are blood repellent. Blood droplets (35 mu L) roll through the tubes at 15 degrees sliding angles without leaving a bloodstain. The tube surface is resistant to adhesion of activated platelets unlike planar control titania and smooth PDMS surfaces.Peer reviewe

    Isomeric states close to doubly magic 132^{132}Sn studied with JYFLTRAP

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    The double Penning trap mass spectrometer JYFLTRAP has been employed to measure masses and excitation energies for 11/2−11/2^- isomers in 121^{121}Cd, 123^{123}Cd, 125^{125}Cd and 133^{133}Te, for 1/2−1/2^- isomers in 129^{129}In and 131^{131}In, and for 7−7^- isomers in 130^{130}Sn and 134^{134}Sb. These first direct mass measurements of the Cd and In isomers reveal deviations to the excitation energies based on results from beta-decay experiments and yield new information on neutron- and proton-hole states close to 132^{132}Sn. A new excitation energy of 144(4) keV has been determined for 123^{123}Cdm^m. A good agreement with the precisely known excitation energies of 121^{121}Cdm^m, 130^{130}Snm^m, and 134^{134}Sbm^m has been found.Comment: 10 pages, 6 figures, submitted to Phys. Rev.

    Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V

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    The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and 46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table

    Non-Gaussianity from Instant and Tachyonic Preheating

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    We study non-Gaussianity in two distinct models of preheating: instant and tachyonic. In instant preheating non-Gaussianity is sourced by the local terms generated through the coupled perturbations of the two scalar fields. We find that the non-Gaussianity parameter is given by fNLϕ∌2g<O(1)f_{NL}^{\phi}\sim 2g < O(1), where gg is a coupling constant, so that instant preheating is unlikely to be constrained by WMAP or Planck. In the case of tachyonic preheating non-Gaussianity arises solely from the instability of the tachyon matter and is found to be large. We find that for single field inflation the present WMAP data implies a bound V01/4/MP≀10−4V_{0}^{1/4}/M_{P}\leq 10^{-4} on the scale of tachyonic instability. We argue that the tachyonic preheating limits are useful also for string-motivated inflationary models.Comment: 12 pages, 1 figure, additional discussion, improved constraint on the scale of tachyonic preheatin

    Precision mass measurements of radioactive nuclei at JYFLTRAP

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    The Penning trap mass spectrometer JYFLTRAP was used to measure the atomic masses of radioactive nuclei with an uncertainty better than 10 keV. The atomic masses of the neutron-deficient nuclei around the N = Z line were measured to improve the understanding of the rp-process path and the SbSnTe cycle. Furthermore, the masses of the neutron-rich gallium (Z = 31) to palladium (Z = 46) nuclei have been measured. The physics impacts on the nuclear structure and the r-process paths are reviewed. A better understanding of the nuclear deformation is presented by studying the pairing energy around A = 100.Comment: 4 pages and 4 figures, RNB7 conf. pro
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