Birth outcome in relation to licorice consumption during pregnancy.

A role for glucocorticoids is suspected in the etiology of low birth weight. The authors tested whether maternal consumption of glycyrrhizin (an inhibitor of cortisol metabolism) in licorice affects birth weight in humans. A sample of 1,049 Finnish women and their healthy singleton infants was studied in 1998. Glycyrrhizin intake was calculated from detailed questionnaires on licorice consumption. Glycyrrhizin exposure was grouped into three levels: low ( or =500 mg/week; n = 110). Birth weight and gestational age (from ultrasound measurements) were obtained from hospital records. Babies with heavy exposure to glycyrrhizin were not significantly lighter at birth, but they were significantly more likely to be born earlier: The odds ratio for being born before 38 weeks' gestation was 2.5 (95% confidence interval: 1.1, 5.5; p = 0.03). Although the effect of heavy glycyrrhizin intake on mean duration of gestation was small (2.52 days) when expressed as an effect on the mean, this shift to the left of the distribution of duration of gestation was sufficient to double the risk of being born before 38 weeks. The association remained in multivariate analyses. In conclusion, heavy glycyrrhizin exposure during pregnancy did not significantly affect birth weight or maternal blood pressure, but it was significantly associated with lower gestational age

Magnetic properties of substitutional Mn in (110) GaAs surface and subsurface layers

Motivated by recent STM experiments, we present a theoretical study of the electronic and magnetic properties of the Mn-induced acceptor level obtained by substituting a single Ga atom in the (110) surface layer of GaAs or in one of the atoms layers below the surface. We employ a kinetic-exchange tight-binding model in which the relaxation of the (110) surface is taken into account. The acceptor wave function is strongly anisotropic in space and its detailed features depend on the depth of the sublayer in which the Mn atom is located. The local-density-of-states (LDOS) on the (110) surface associated with the acceptor level is more sensitive to the direction of the Mn magnetic moment when the Mn atom is located further below the surface. We show that the total magnetic anisotropy energy of the system is due almost entirely to the dependence of the acceptor level energy on Mn spin orientation, and that this quantity is strongly dependent on the depth of the Mn atom.Comment: 14 pages, 13 figure

Chern number spins of Mn acceptor magnets in GaAs

We determine the effective total spin $J$ of local moments formed from acceptor states bound to Mn ions in GaAs by evaluating their magnetic Chern numbers. We find that when individual Mn atoms are close to the sample surface, the total spin changes from $J = 1$ to $J = 2$, due to quenching of the acceptor orbital moment. For Mn pairs in bulk, the total $J$ depends on the pair orientation in the GaAs lattice and on the separation between the Mn atoms. We point out that Berry curvature variation as a function of local moment orientation can profoundly influence the quantum spin dynamics of these magnetic entities.Comment: 4 pages, 3 figure

Magnetic interactions of substitutional Mn pairs in GaAs

We employ a kinetic-exchange tight-binding model to calculate the magnetic interaction and anisotropy energies of a pair of substitutional Mn atoms in GaAs as a function of their separation distance and direction. We find that the most energetically stable configuration is usually one in which the spins are ferromagnetically aligned along the vector connecting the Mn atoms. The ferromagnetic configuration is characterized by a splitting of the topmost unoccupied acceptor levels, which is visible in scanning tunneling microscope studies when the pair is close to the surface and is strongly dependent on pair orientation. The largest acceptor splittings occur when the Mn pair is oriented along the symmetry direction, and the smallest when they are oriented along . We show explicitly that the acceptor splitting is not simply related to the effective exchange interaction between the Mn local moments. The exchange interaction constant is instead more directly related to the width of the distribution of all impurity levels -- occupied and unoccupied. When the Mn pair is at the (110) GaAs surface, both acceptor splitting and effective exchange interaction are very small except for the smallest possible Mn separation.Comment: 25 figure

Microwave Spectroscopy

Contains reports on three research projects.Signal Corps Contract DA36-039-sc-7489

Magnetic Anisotropy of Isolated Cobalt Nanoplatelets

Motivated in part by experiments performed by M.H. Pan et al. (nanoletters, v.5, p 83, 2005), we have undertaken a theoretical study of the the magnetic properties of two-monolayer thick Co nanoplatelets with an equilateral triangular shape. The analysis is carried out using a microscopic Slater-Koster tight-binding model with atomic exchange and spin-orbit interactions designed to realistically capture the salient magnetic features of large nanoclusters containing up to 350 atoms. Two different truncations of the FCC lattice are studied, in which the nanoplatelet surface is aligned parallel to the FCC (111) and (001)crystal planes respectively. We find that the higher coordination number in the (111) truncated crystal is more likely to reproduce the perpendicular easy direction found in experiment. Qualitatively, the most important parameter governing the anisotropy of the model is found to be the value of the intra-atomic exchange integral J. If we set the value of J near the bulk value in order to reproduce the experimentally observed magnitude of the magnetic moments, we find both quasi-easy-planes and perpendicular easy directions. At larger values of J we find that the easy-axis of magnetization is perpendicular to the surface, and the value of the magnetic anisotropy energy per atom is larger. The possible role of hybridization with substrate surface states in the experimental systems is discussed.Comment: 15 pages, 13 figure

Microwave Spectroscopy

Contains reports on three research projects

Muistisairaiden liikunnallisen kuntoutuksen vaikuttavuus : Satunnaistettu vertailutukimus

Tutkimuksen tavoitteena oli selvittää satunnaistetulla,kontrolloidulla asetelmalla liikunnallisen harjoittelun vaikuttavuutta kotona asuvien, Alzheimerin tautia sairastavien toimintakyvyn eri ulottuvuuksiin, heidän omaishoitajiensa elämänlaatuun sekä molempien palveluiden käyttöön ja niiden kustannuksiin vuosina 2008–2011. Tutkimukseen osallistui 210 pariskuntaa, joista toinen puoliso oli muistisairaan omaishoitaja. Pariskunnat randomoitiin kolmeen yhtä suureen ryhmään: 1) ryhmäkuntoutusryhmään (liikuntaharjoittelua neljä tuntia kaksi kertaa viikossa päiväkeskuksessa vuoden ajan), 2) kotikuntoutusryhmään (tunti kaksi kertaa viikossa kotona vuoden ajan fysioterapeutin ohjauksessa) ja 3) vertailuryhmään (tavallinen kunnallinen hoito). Tutkimushoitajan haastattelut tehtiin lähtötilanteessa sekä 3:n, 6:n, 12:n ja 24 kuukauden kohdalla. Päätulosmuuttujat olivat muistisairaan ihmisen toimintakyky (mitattiin FIM-toimintakykymittarilla) sekä liikuntakyky (mitattiin Guralnikin liikuntakyky- ja tasapainotesteillä = SPPB). Kotona annetulla räätälöidyllä kuntoutuksella voidaan hidastaa muistisairaiden fyysisen toimintakyvyn (mitattu FIM-mittarilla) heikkenemistä merkitsevästi. Liikuntatesteissä (SPPB) ei ollut eroja ryhmien välillä. Myös kognitiossa näkyi myönteinen muutos toiminnanohjauksen osalta kellotestillä mitattuna kotikuntoutusryhmässä. Ryhmäkuntoutuksessa palveluiden kokonaiskustannusten säästöt olivat merkittävät, joskaan muutokset toimintakyvyssä eivät saavuttaneet tilastollista merkitsevyyttä. Omaisten elämänlaadussa tai muissa mittareissa ei ollut merkitseviä eroja interventioryhmien ja vertailuryhmien välillä. Kaatumiset vähenivät molemmissa interventioryhmissä. Kuolemanvaara näytti pienentyneen kotikuntoutusryhmässä. Tutkimuksessa luotiin kuntoutusmalli, joka parantaa Alzheimerin tautia sairastavien toimintakykyä lisäämättä sosiaali- ja terveyspalveluiden kokonaiskustannuksia.15,00 euro