Sökresultat

Filtyp

Din sökning på "*" gav 535705 sökträffar

The influence of predator regime on reproductive traits in Gammarus pulex populations

Selection on traits conferring reduced predation may be opposed by selection on other traits associated with reproduction. Here, we examined the hypothesis that traits associated with reproduction in Gammarus pulex are driven by predation. We studied G. pulex originating from ponds with two different kinds of predator regimes: (1) ponds with fish-often large, non-gap-limited predators and (2) pond

Application of antisense transformation of a barley chitinase in studies of arbuscule formation by a mycorrhizal fungus

Barley (Hordeum vulgare L.) plants of two commercial cultivars were transformed with sense and antisense constructs of a chitinase class II gene in order to develop a transformation system for this gene in barley. Transformation of embryos with the two antisense constructs resulted in ten regenerated plants, while no plants could be obtained using the sense construct. The presence of the inserted

Tumor necrosis factor (TNF)-mediated activation of the p55 TNF receptor negatively regulates maintenance of cycling reconstituting human hematopoietic stem cells

Hematopoietic stem cell (HSC) fate decisions between self-renewal and commitment toward differentiation are tightly regulated in vivo. Recent developments in HSC culture and improvements of human HSC assays have facilitated studies of these processes in vitro. Through such studies stimulatory cytokines critically involved in HSC maintenance in vivo have been demonstrated to also promote HSC self-r

Some attacks on the Bit-search generator

The bit-search generator (BSG) was proposed in 2004 and can be seen as a variant of the shrinking and self-shrinking generators. It has the advantage that it works at rate 1/3 using only one LFSR and some selection logic. We present various attacks on the BSG based on the fact that the output sequence can be uniquely defined by the differential of the input sequence. By knowing only a small part o

The MSX1 homeobox transcription factor is a downstream target of PHOX2B and activates the Delta-Notch pathway in neuroblastoma

Neuroblastoma is an embryonal tumour of the peripheral sympathetic nervous system (SNS). One of the master regulator genes for peripheral SNS differentiation, the homeobox transcription factor PHOX2B, is mutated in familiar and sporadic neuroblastomas. Here we report that inducible expression of PHOX2B in the neuroblastoma cell line SJNB-8 down-regulates MSX1, a homeobox gene important for embryon

The menopause revisited

The continuing growth of female life expectancy has resulted in a marked increase of women in years beyond the menopause. Women can nowadays expect to live one-third of their lives in a potential hormonal deficiency state. Women over 50 comprise 17% of the total population of any country in the modern western world. Any decision regarding their health issues will have a great impact on our limited

Energy Simulations for Glazed Office Buildings in Sweden

Highly glazed buildings are designed by architects to be airy, light and transparent with more access to daylight. Their energy efficiency, however, has become questioned. Therefore, energy simulations of single skin office buildings in Sweden were carried out, using a dynamic energy simulation tool. In order to study the impact of glass on the energy use during the occupation stage, office buildi

Association of HLA-DQ5 and HLA-DR1 with sensitization to organic acidanhydrides

Background Organic acid anhydrides are low molecular weight industrial chemicals, able to cause rhinoconjunctivitis and asthma associated with specific IgE against hapten-carrier protein conjugate. Only a proportion of exposed workers develop IgE-associated allergy to acid anhydrides. Objective We determined whether genetic susceptibility, in particular, HLA Class II alleles may be a risk factor.

A new strychnos alkaloid from Strychnos scheffleri

A phytochemical investigation of the stem bark of Strychnos scheffleri resulted in the isolation of a new strychnos alkaloid N-a-deacetylmalagashine (1) together with the known derivative malagashine (2). Elucidation of the structures was based mainly on ID and 2D NMR and MS studies and by comparison with related compounds.

Decrease in intramuscular lipid droplets and translocation of HSL in response to muscle contraction and epinephrine

A better understanding of skeletal muscle lipid metabolism is needed to identify the molecular mechanisms relating intramuscular triglyceride (IMTG) to muscle metabolism and insulin sensitivity. An increasing number of proteins have been reported to be associated with intracellular triglyceride (TG), among them the PAT family members: perilipin, ADRP ( for adipocyte differentiation-related protein

Effects of the combined ETA and ETB receptor antagonist PD145065 on arteries, arterioles, and veins in the cat hindlimb

The aim of this study was to describe in quantitative terms the effects of ETA and ETB receptor blockade on vascular tone (resistance) in large-bore arterial resistance vessels (> 25 microns), small arterioles (< 25 microns), and veins in the cat gastrocnemius muscle in vivo. In the muscle vascular bed, the combined ETA and ETB receptor antagonist PD145065 (1 mg/kg/min, intra-arterially) abolished

Validation of Gastrointestinal Quality of Life Index in Swedish for Assessing the Impact of Gallstones on Health-Related Quality of Life

The aim of the present study was to validate a Swedish translation of the Gastrointestinal Quality of Life Index (GIQLI) questionnaire in patients with gallstone disease. Sensitivity to change, internal consistency, and test-retest stability were tested in 187 consecutive patients who underwent planned cholecystectomy. Construct validity was assessed by comparing the GIQLI score with the bodily pa

Effect of different cooking methods on the formation of mutagenic compounds in meat.

Hamburgers and chicken fillets were cooked in convection ovens, deep-fried or contact fried and analysed for mutagenic activity using the Ames test. For the three different convection ovens, the cooking parameters studied included the presence of steam, air velocity, air temperature and holding time. For deep-frying and contact frying, the cooking parameters included cooking temperature and cookin

A non-Newtonian model based on limiting shear stress and slip planes - parametric studies

Parametric studies and corresponding results are presented using a theological model based on the limiting shear stress and possible occurrence of slip planes. The model is applied to elastohydrodynamically lubricated line contacts with smooth surfaces and isothermal conditions. A few investigations are carried out where different parameters are varied. The first study investigates the influence o

Strategy-proof and nonbossy allocation of indivisible goods and money

Which strategy-proof nonbossy mechanisms exist in a model with a finite number of indivisible goods (houses, jobs, positions) and a perfectly divisible good (money)? The main finding is that only a finite number of distributions of the divisible good is consistent with strategy-proofness and nonbossiness. Under various additional assumptions - neutrality, individual rationality, object efficiency,

Duality in $H^infty$ Cone Optimization

Positive real cones in the space $H^infty$ appear naturally in many optimization problems of control theory and signal processing. Although such problems can be solved by finite-dimensional approximations (e.g., Ritz projection), all such approximations are conservative, providing one-sided bounds for the optimal value. In order to obtain both upper and lower bounds of the optimal value, a dual pr

How complete and correct was Linnaeus’ knowledge and classification of the Swedish flora?

The degree to which Carolus Linnaeus managed to describe the vascular plant species diversity of his native country, and the proportion of his taxonomic decisions concerning the rank and generic classification of these same species that are considered correct by present-day taxonomists, is analyzed by comparing the most recent checklist of the Swedish flora, excluding later immigrants, with the wo

High GATA-2 expression inhibits human hematopoietic stem and progenitor cell function by effects on cell cycle

Evidence suggests the transcription factor GATA-2 is a critical regulator of murine hematopoietic stem cells. Here, we explore the relation between GATA-2 and cell proliferation and show that inducing GATA-2 increases quiescence (G(0) residency) of murine and human hematopoietic cells. In human cord blood, quiescent fractions (CD34(+)CD38(-)Hoechst(lo)Pyronin Y-lo) express more GATA-2 than cycling