Fibre composition and enzyme activities in six muscles of the Swedish reindeer (Rangifer tarandus tarandus)

Six skeletal muscles have been studied as regards fibre properties and enzyme activities. The muscles are cranial part of M. gluteobiceps, M. semitendinosus, M. semimembranosus, M. longissimus dorsi, M. brachiocephalicus and M. sternocephalicus. Two histochemical methods were used for fibre identification, one based on myosin ATPase activities after preincubation at pH 4.3 and 4.6 and the other on oxidative capacity measured as NADH dehydrogenase activity. The two methods gave slightly differing results but allowed the general conclusion that of the three fibre types (I, II A and II B) the type II B fibres, which are fast-twitch, glycolytic, make up some 40 - 60 % (mean 50 %) of the muscles. Type I fibres, which are slow-twitch, oxidative, account for 30% of the total muscle volume in the two neck muscles but for only 20% or less in the rest. The third type, II A, which is fast-twitch, oxidative, glycolytic, accounts for only 20% of the volume in the neck muscles but as much as 40% in M. longissimus dorsi. Oxidative capacity is high throughout. This is valid also to the capacity to oxidize fatty acids, though reaching only half the activity previously found in the Svalbard reindeer (Kiessling and Kiessling, 1983). Lactate dehydrogenase activity is comparatively low in all muscles. The high respiratory chain activity and fatty acid oxidation and the low lactate dehydrogenase activities do not fit at all well with the high content of type II B fibres in the muscles. This high II B content is also unexpected when considering the activity pattern of the reindeer. An altogether different role for the type II B fibres, besides the traditional one, is therefore discussed.Fibersammansåttning och enzymaktiviteter i sex muskler från svensk tamren (Rangifer tarandus tarandus).Abstract in Swedish / Sammandrag: Sex skelettmuskler har undersokts med avseende på fiberegenskaper och enzymaktiviteter. De sex musklerna år kranial del av M. gluteobiceps. M. semitendinosus, M. semimembranosus, M. longissimus dorsi, M. brachiocephalicus och M. sternocephalicus. Två histokemiska metoder har anvånts for att identifiera fibrerna, den ena baserad på myosin ATPas aktivitet efter forinkubering vid pH 4,3 och 4,6, den andre på oxidativ kapacitet mått som NADH dehydrogenas aktivitet. De två metoderna gav något olika resultat men tillater den generella slutsatsen att av de tre fibertyperna (I, II A och II B) typ II B fibrerna, som ar snabbt kontraherande, glykolytiska, utgor 40 - 60 % (medelvårde 50 %) av muskelvolymen. Typ I fibrerna, som år langsamt kontraherande, oxidativa, svarar for 30% av totala muskelvolymen i de två halsmusklerna men bara for 20% eller mindre i ovriga muskler. Den tredje typen, II A, som år snabbt kontraherande, oxidativ och glykolytisk, svarar bara for 20 % av volymen i halsmusklerna men enda upp till 40% i M. longissimus dorsi. Den oxidativa kapaciteten år genomgående hog. Detta gåiler aven for kapaciteten att oxidera fettsyror, aven om denna bara uppgår till halva den aktivitet som tidigare påvisats i Svalbardrenens muskler (Kiessling & Kiessling 1983). Laktatdehydrogenas aktiviteten år jåmforelsevis låg i alla muskler. Den hoga aktiviteten hos andingskedjan och fettsyraoxidationen och den låga laktatdehydrogenas aktiviteten ståmmer dåligt med den hoga halten av typ II B fibrer i musklerna. Denna hoga II B halt år också ovåntad med tanke på renens aktivitetsmonster. Dårfor diskuteras en alternativ roll for typ II B fibrerna forutom den traditionella att fungera som kontraktil våvnad.Fiiberien kokoonpano ja entsyymien aktiivisuudet kuudessa lihaksessa ruotsalaisessa porossa. (Rangifer tarandus tarandus).Abstract in Finnish / Yhteenveto: On tutkittu kuutta luurangon lihasta mita fiiberien ominaisuuksiin ja entsyymien aktiivisuuksiin tulee. Lihakset ovat craniaalinen osa seuraavista: M. gluteobiceps, M. semkendmosus, M. semimembranosus, M. longissimus dorsi, M. brachiocephalicus ja M. sternocephalicus. Fiiberien identifioitiin kaytettiin kahta histokemiallista menetelmaa, ensimmainen perustui myosin ATPase aktiivisuuksiin preinkubaation jalkeen pH 4,3:ssa ja 4,6:ssa ja toinen oksidatiiviseen kapasiteettiin mitattuna NADH dehydrogenase aktiivisuutena. Nama kaksi menetelmaa antoivat hienoisen eron, mutta antaa aihetta yleiseen johtopaatokseen, etta niista kolmesta fiiberityypista (I, II A ja II B) tyyppi II B fiiberit, jotka ovat nopeasti supistavia, glycolyyttisia, koostuvat suunnilleen 40 - 60 % (keskimaarin 50 %) lihaksista. Tyyppi I fiiberit, jotka ovat hitaasti supistavia, oksidatiivisia, tekee 30 % lihaksen kokonaismaarasta niissa kahdessa niskalihaksessa, mutta vain 20 % tai vahemman muissa. Kolmas tyyppi, II A, joka on nopeasti supistava, oxidatiivinen, glycolyyttinen, tekee vain 20 % niskalihasten maarasta, mutta niin paljon kuin 40 % M. longissimus dorsi.sta. Oksidatiivinen kapasiteetti on lapeensa korkea. Tama patee myoskin kapasiteettiin oksidoida rasvahappoa, vaikkakin saavuttaa vain puolet aktiivisuudesta aikaisemmista loydoista Huippuvuorten poroissa (Kiessling ja Kiessling, 1983). Lactate dehydrogenase aktiivisuus on verrattain alhainen kaikissa lihaksissa. Korkea respiraatioketju aktiiviteetti ja rasvahappo oksidaatio seka alhainen lactate dehydrogenase aktiivisuudet eivat sovi laisinkaan hyvin yhteen korkea sisaltoisten tyyppi II B fiiberien kanssa lihaksissa. Tama korkea II B sisaltoinen on myoskin odottamaton huomioonottaen poron aktiivisuus kayttaytymisen. Aivan erilainen tehtava tyyppi II B fiibereille, traditionaaliseen verrattuna, on siksi keskusteltu

Van der Waals Density Functional for General Geometries

A scheme within density functional theory is proposed that provides a practical way to generalize to unrestricted geometries the method applied with some success to layered geometries [H. Rydberg, et al., Phys. Rev. Lett. 91, 126402 (2003)]. It includes van der Waals forces in a seamless fashion. By expansion to second order in a carefully chosen quantity contained in the long range part of the correlation functional, the nonlocal correlations are expressed in terms of a density-density interaction formula. It contains a relatively simple parametrized kernel, with parameters determined by the local density and its gradient. The proposed functional is applied to rare gas and benzene dimers, where it is shown to give a realistic description.Comment: 4 pages, 4 figure

Nature and strength of bonding in a crystal of semiconducting nanotubes: van der Waals density functional calculations and analytical results

The dispersive interaction between nanotubes is investigated through ab initio theory calculations and in an analytical approximation. A van der Waals density functional (vdW-DF) [Phys. Rev. Lett. 92, 246401 (2004)] is used to determine and compare the binding of a pair of nanotubes as well as in a nanotube crystal. To analyze the interaction and determine the importance of morphology, we furthermore compare results of our ab initio calculations with a simple analytical result that we obtain for a pair of well-separated nanotubes. In contrast to traditional density functional theory calculations, the vdW-DF study predicts an intertube vdW bonding with a strength that is consistent with recent observations for the interlayer binding in graphitics. It also produce a nanotube wall-to-wall separation which is in very good agreement with experiments. Moreover, we find that the vdW-DF result for the nanotube-crystal binding energy can be approximated by a sum of nanotube-pair interactions when these are calculated in vdW-DF. This observation suggests a framework for an efficient implementation of quantum-physical modeling of the CNT bundling in more general nanotube bundles, including nanotube yarn and rope structures.Comment: 10 pages, 4 figure

Transferrin variation and genetic structure of reindeer populations in Scandinavia

Polyacrylamide gel electrophoresis was used to analyse transferrin variation in herds of semi-domestic reindeer from Scandinavia. The results are compared with previously reported values for other populations of both semi-domestic and wild reindeer using the same techniques as in the present study. In all populations the number of alleles was high, ranging from seven to eleven, and the heterozygosity was correspondingly high, with a mean of 0.749. This high genetic variation in all populations suggests that inbreeding is not widespread among Scandinavian reindeer. The pattern of allele frequency distribution indicates a high degree of genetic heterogeneity in the transferrin locus, both between the different semi-domestic herds and between the different wild populations. The mean value of genetic distance was 0.069 between semi-domestic herds and 0.091 between wild populations. Between semi-domestic and wild populations the genetic distance was particularly high, with a mean of 0.188. This high value was mainly due to a different pattern in the distribution of the two most common transferrin alleles: Tfu was most common among semi-domestic herds, while TfEI was most common among wild populations. These differences in transferrin allele distribution are discussed in relation to possible different origins of semi-domestic and wild reindeer in Scandinavia, or alternatively, to different selection forces acting on transferrin genotypes in semi-domestic and wild populations.Transferrin-variasjon og genetisk struktur hos rein i Skandinavia.Abstact in Norwegian / Sammendrag: Transferrin-variasjon i tamreinflokker ble analysert ved hjelp av polyacrylamid gel elektroforese. Resultatene er sammenlignet med verdier som tidligere er beskrevet for både tamrein og villrein hvor det ble benyttet samme metode som i denne undersøkelsen. I alle populasjonene ble det registrert et høyt antall alleler (7-11) og heterozygositeten var tilsvarende høy med en middelverdi på 0.749. Denne høye graden av genetisk variasjon i alle undersøkte populasjoner indikerer at det ikke foregår mye innavl blant rein i Skandinavia. Utbredelsen av de enkelte allelene viste høy grad av genetisk oppdeling i transferrin-locuset mellom flokker av både tamrein og villrein. Middelverdien for genetisk avstand var 0.069 mellom tamreinflokker og 0.091 mellom villreinflokker. Særlig stor genetisk avstand (middelverdi 0.188) ble funnet mellom tamrein og villrein. Denne store forskjellen skyldes i stor grad forskjellig mønster i utbredelsen av de to vanligste allelene: Tf' var mest vanlig blant tamrein og Tf1' var mest vanlig blant villrein. Denne forskjellen er diskutert i relasjon til forskjellig opprinnelse av tamrein og villrein og alternativt, i relasjon til forskjellig seleksjonskrefter som virker på transferrin genotyper i tamrein og villrein

Enhanced dispersion interaction between quasi-one dimensional conducting collinear structures

Recent investigations have highlighted the failure of a sum of $R^{-6}$ terms to represent the dispersion interaction in parallel metallic, anisotropic, linear or planar nanostructures [J. F. Dobson, A. White, and A. Rubio, Phys. Rev. Lett. 96, 073201 (2006) and references therein]. By applying a simple coupled plasmon approach and using electron hydrodynamics, we numerically evaluate the dispersion (non-contact van der Waals) interaction between two conducting wires in a collinear pointing configuration. This case is compared to that of two insulating wires in an identical geometry, where the dispersion interaction is modelled both within a pairwise summation framework, and by adding a pinning potential to our theory leading to a standard oscillator-type model of insulating dielectric behavior. Our results provide a further example of enhanced dispersion interaction between two conducting nanosystems compared to the case of two insulating ones. Unlike our previous work, this calculation explores a region of relatively close coupling where, although the electronic clouds do not overlap, we are still far from the asymptotic region where a single power law describes the dispersion energy. We find that strong differences in dispersion attraction between metallic and semiconducting / insulating cases persist into this non-asymptotic region. While our theory will need to be supplemented with additional short-ranged terms when the electronic clouds overlap, it does not suffer from the short-distance divergence exhibited by purely asymptotic theories, and gives a natural saturation of the dispersion energy as the wires come into contact.Comment: 10 pages, 5 figures. Added new extended numerical calculations, new figures, extra references and heavily revised tex

FoldIndex©: a simple tool to predict whether a given protein sequence is intrinsically unfolded

Summary: An easy-to-use, versatile and freely available graphic web server, FoldIndex© is described: it predicts if a given protein sequence is intrinsically unfolded implementing the algorithm of Uversky and co-workers, which is based on the average residue hydrophobicity and net charge of the sequence. FoldIndex© has an error rate comparable to that of more sophisticated fold prediction methods. Sliding windows permit identification of large regions within a protein that possess folding propensities different from those of the whole protein. Availability: FoldIndex© can be accessed at http://bioportal.weizmann.ac.il/fldbin/findex Contact: [email protected] Supplementary information: http://www.weizmann.ac.il/sb/faculty_pages/Sussman/papers/suppl/Prilusky_200

Atomic Supersymmetry, Rydberg Wave Packets, and Radial Squeezed States

We study radial wave packets produced by short-pulsed laser fields acting on Rydberg atoms, using analytical tools from supersymmetry-based quantum-defect theory. We begin with a time-dependent perturbative calculation for alkali-metal atoms, incorporating the atomic-excitation process. This provides insight into the general wave packet behavior and demonstrates agreement with conventional theory. We then obtain an alternative analytical description of a radial wave packet as a member of a particular family of squeezed states, which we call radial squeezed states. By construction, these have close to minimum uncertainty in the radial coordinates during the first pass through the outer apsidal point. The properties of radial squeezed states are investigated, and they are shown to provide a description of certain aspects of Rydberg atoms excited by short-pulsed laser fields. We derive expressions for the time evolution and the autocorrelation of the radial squeezed states, and we study numerically and analytically their behavior in several alkali-metal atoms. Full and fractional revivals are observed. Comparisons show agreement with other theoretical results and with experiment.Comment: published in Physical Review

Passive and active suicidal ideation in a population-based sample of older adults: Associations with polygenic risk scores of relevance for suicidal behavior

Introduction: There are few studies investigating genetic factors related to suicidal ideation or behavior in older adult populations. Our aim was to test associations between passive and active suicidal ideation and polygenic risk scores (PRSs) for suicidality and other traits of relevance for suicidality in old age (i.e. depression, neuroticism, loneliness, Alzheimer’s disease, cognitive performance, educational attainment, and several specified vascular diseases) in a population-based sample aged 70 years and older. / Methods: Participants in the prospective H70 study in Gothenburg, Sweden, took part in a psychiatric examination that included the Paykel questions on active and passive suicidal ideation. Genotyping was performed with the Neurochip (Illumina). After quality control of the genetic data the sample included 3467 participants. PRSs for suicidality and other related traits were calculated based on summary statistics from recent GWASs of relevance. Exclusion of persons with dementia or incomplete data on suicidal ideation yielded 3019 participants, age range 70–101 years. Associations between past year suicidal ideation (any level) and selected PRSs were analysed using general estimation equation (GEE) models, adjusted for sex and age. / Results: We observed associations between passive/active suicidal ideation and PRSs for depression (three versions), neuroticism, and general cognitive performance. After excluding individuals with current major depressive disorder (MDD), similar associations were seen with PRS for neuroticism, general cognitive performance and two PRSs for depression. No associations were found between suicidal ideation and PRSs for suicidality, loneliness, Alzheimer’s disease, educational attainment, or vascular disease. / Discussion: Our results could indicate which types of genetic susceptibility that are of importance for suicidality in old age, and these findings can help to shed light on potential mechanisms that may be involved in passive and active suicidal ideation in late-life, also in those with no current MDD. However, due to the limited sample size, the results need to be interpreted with caution until replicated in larger samples

Semiconducting Monolayer Materials as a Tunable Platform for Excitonic Solar Cells

The recent advent of two-dimensional monolayer materials with tunable optoelectronic properties and high carrier mobility offers renewed opportunities for efficient, ultra-thin excitonic solar cells alternative to those based on conjugated polymer and small molecule donors. Using first-principles density functional theory and many-body calculations, we demonstrate that monolayers of hexagonal BN and graphene (CBN) combined with commonly used acceptors such as PCBM fullerene or semiconducting carbon nanotubes can provide excitonic solar cells with tunable absorber gap, donor-acceptor interface band alignment, and power conversion efficiency, as well as novel device architectures. For the case of CBN-PCBM devices, we predict the limit of power conversion efficiencies to be in the 10 - 20% range depending on the CBN monolayer structure. Our results demonstrate the possibility of using monolayer materials in tunable, efficient, polymer-free thin-film solar cells in which unexplored exciton and carrier transport regimes are at play.Comment: 7 pages, 5 figure

Many-body GW calculations of ground-state properties: Quasi-2D electron systems and van der Waals forces

We present GW many-body results for ground-state properties of two simple but very distinct families of inhomogeneous systems in which traditional implementations of density-functional theory (DFT) fail drastically. The GW approach gives notably better results than the well-known random-phase approximation, at a similar computational cost. These results establish GW as a superior alternative to standard DFT schemes without the expensive numerical effort required by quantum Monte Carlo simulations