1,530 research outputs found
Modelling mineral dust using stereophotogrammetry
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 2008â2016 OYS:ssa kuolleiden lasten soveltuvuus elinluovuttajiksi
TiivistelmÀ. Suomessa lapsikuolleisuus on nykyÀÀn pienempiÀ maailman tasolla. Lasten kuolleisuus on Suomessa pienentynyt koko viime vuosisadan ajan. Lain mukaan ihminen on kuollut, kun kaikki hÀnen aivotoimintonsa ovat pysyvÀsti loppuneet. Kuolema voidaan todeta sydÀmen vielÀ sykkiessÀ, kun tutkittaessa aivoperÀiset vasteet puuttuvat ja todetaan ettÀ hengityskeskuksen toiminta on loppunut. Aivokuoleman mÀÀritelmÀ 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, sydÀmen ja keuhkojen sairauksissa. Lapset eivÀt sÀÀsty elinsiirtojonoissa olemiselta ja lista elinsiirtoa odottavista lapsista on kasvanut. Lapsipotilaiden mÀÀrÀ 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 2008â2016 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
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
â all of them inhomogeneous â 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
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
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 Sn studied with JYFLTRAP
The double Penning trap mass spectrometer JYFLTRAP has been employed to
measure masses and excitation energies for isomers in Cd,
Cd, Cd and Te, for isomers in In and
In, and for isomers in Sn and 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 Sn. A new
excitation energy of 144(4) keV has been determined for Cd. A good
agreement with the precisely known excitation energies of Cd,
Sn, and Sb 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
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
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 ,
where 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 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
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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