Sökresultat

Filtyp

Din sökning på "*" gav 530672 sökträffar

Morphometric variation in a hybrid zone between the weed, Silene vulgaris, and the endemic, Silene uniflora ssp petraea (Caryophyllaceae), on the Baltic island of Oland

On the island of Oland the weed, Silene vulgaris (Moench) Garcke, and the endemic, Silene uniflora Roth ssp. petraea, hybridize when brought into contact by anthropogenic disturbance. Variation was studied in transects across a hybrid zone where a linear population of S. vulgaris crossed the native habitat of S. uniflora ssp. petraea. Plants were scored for 20 morphological characters. Although in

A pancreatic islet-specific microRNA regulates insulin secretion

MicroRNAs (miRNAs) constitute a growing class of non-coding RNAs that are thought to regulate gene expression by translational repression(1). Several miRNAs in animals exhibit tissue-specific or developmental-stage-specific expression, indicating that they could play important roles in many biological processes(2-4). To study the role of miRNAs in pancreatic endocrine cells we cloned and identifie

Clinical, immunological and bacteriological evaluation of adverse reactions to skin-penetrating titanium implants in the head and neck region

Between 1977 and October 1989, 445 patients have been treated with bone-anchored skin-penetrating titanium implants for anchorage of facial prostheses or bone-conducting hearing aids, at the Ear, Nose and Throat Department at Sahlgren's Hospital in Gothenburg. The majority of patients had no adverse skin reactions, while a few patients were responsible for the majority of the adverse reactions. Th

In vitro formation of nanocrystalline carbonate apatite - A structural and morphological analogue of atherosclerotic plaques

The in vitro formation of carbonate apatite in solutions with ion concentrations comparable to those in human serum was studied. The composition and morphology of the resulting apatite precipitate displayed a hierarchical assembly of elongated plate-shaped nanocrystals of carbonate apatite analogous to previously characterized bioapatites formed in The main conclusion is that so-called bioapatites

Gram-negative bacteria induce proinflammatory cytokine production by monocytes in the absence of lipopolysaccharide (LPS)

Tumour necrosis factor-alpha (TNF-alpha), IL-1alpha and IL-6 production by human monocytes in response to a clinical strain of the Gram-negative encapsulated bacteria Neisseria meningitidis and an isogenic lpxA- strain deficient in LPS was investigated. Wild-type N. meningitidis at concentrations between 105 and 108 organisms/ml and purified LPS induced proinflammatory cytokine production. High le

Construction of cellobiose-growing and fermenting Saccharomyces cerevisiae strains

beta-Glucosidase genes of fungal origins were isolated and heterologously expressed in Saccharomyces cerevisiae to enable growth on the disaccharide, cellobiose. To promote secretion of the beta-glucosidases, the genes were fused to the secretion signal of the Trichoderma reesei xyn2 gene and constitutively expressed from a multi-copy yeast expression vector under transcriptional control of the S.

The dependence of aerosol effects on clouds and precipitation on cloud-system organization, shear and stability

Precipitation suppression due to an increase of aerosol number concentration in stratiform cloud is well-known. It is not certain whether the suppression applies for deep convection. Recent studies have suggested increasing precipitation from deep convection with increasing aerosols under some, but not all, conditions. Increasing precipitation with increasing aerosols can result from strong intera

Autism spectrum disorder and underlying brain mechanism in the oculoauriculovertebral spectrum

As part of a multidisciplinary study, the rate of autism spectrum disorder (ASD), learning disability (LD), and brain abnormalities was examined in 20 participants (12 males, 8 females; age range 8mo-17y, mean age 8y 1mo) diagnosed as falling within the oculoauriculovertebral spectrum (OAV). A neuropsychiatric examination was performed, including standardized autism diagnostic interviews. Two indi

Quantum ratchets and quantum heat pumps

Quantum ratchets are Brownian motors in which the quantum dynamics of particles induces qualitatively new behavior. We review a series of experiments in which asymmetric semiconductor devices of sub-micron dimensions are used to study quantum ratchets for electrons. In rocked quantum-dot ratchets electron-wave interference is used to create a non-linear voltage response, leading to a ratchet effec

Growing syntactic structure and code-mixing in the weaker language: The Ivy Hypothesis

We present a hypothesis for a specific kind of code-mixing in young bilingual children, during the development of their two first languages, one of which is considerably weaker than the other. Our hypothesis, which we label the Ivy Hypothesis, is that, in the interaction meant to be in the weaker language, the child uses portions of higher syntactic structure lexically instantiated in the stronger

Progress in haemophilic care: ethical issues.

Care of haemophilic patients has dramatically improved during the past 40-50 years. Clotting factor concentrates have become much safer. Expensive treatments such as prophylaxis, immune-tolerance induction, the use of bypassing agents in inhibitor patients, and the replacement of joints have become available. However, there is still a shortage of factor concentrate, and we are yet to discover the

Performance comparison between PID and dead-time compensating controllers

This paper is intended to answer the question: “When is a simple dead-time compensator expected to perform better than a PID?”. The performance criterion used is the integrated absolute error (IAE). It is compared for PI and PID controllers and a simple dead-time compensator (DTC) when a step load disturbance is applied at the plant input. Both stable and integrating processes are considered. For

Surface core level shift of the Be 1s level observed from a Be(0001) single crystal surface

We have used surface sensitive photoelectron spectroscopy to study the Be 1s core level from the Be(0001) single crystal surface. Two core peaks are observed, one from the bulk atoms, and the other from the first layer surface atoms. They are separated in binding energy by 0.50 eV, the surface peak being located at lower binding energy. This experimental surface core level shift (SCS) is compared

Simulating terahertz quantum cascade lasers: Trends from samples from different labs

We present a systematic comparison of the results from our non-equilibrium Green's function formalism with a large number of AlGaAs-GaAs terahertz quantum cascade lasers previously published in the literature. Employing identical material and simulation parameters for all samples, we observe that the discrepancies between measured and calculated peak currents are similar for samples from a given g

Selection of an optimal feature set to predict heart transplantation outcomes

Heart transplantation (HT) is a life saving procedure, but a limited donor supply forces the surgeons to prioritize the recipients. The understanding of factors that predict mortality could help the doctors with this task. The objective of this study is to find locally optimal feature sets to predict survival of HT patients for different time periods. To this end, we applied logistic regression to

In situ hybridization of neuropeptide Y (NPY) mRNA in the goldfish brain

The distribution of neurones expressing neuropeptide Y (NPY) mRNA in the brain of the goldfish was investigated using a non-radioactive in situ hybridization technique. Neurones expressing NPY mRNA were located in cell groups previously shown to exhibit NPY immunoreactivity in the ventral telencephalon, thalamus, optic tectum and a region adjacent to the locus coeruleus. In addition, neurones expr

A boot-strap Poisson-Boltzmann theory for the structure and thermodynamics of chargd colloidal solutions

The structural properties and thermodynamics of one- and two-component solutions of charged colloidal particles with explicit counterions have been investigated by Monte Carlo simulation. A boot-strap Poisson-Boltzmann (BSPB) theory has been developed to interpret these results and the accuracy of its predictions is compared with other existing theories. The BSPB was also used to predict the gas-l

Digitalis: a dangerous drug in atrial fibrillation? An analysis of the SPORTIF III and V data

OBJECTIVE: In heart failure, digitalis increases exercise capacity and reduces morbidity, but has no effect on survival. This raises the suspicion that the inotropic benefits of digitalis may be counteracted by serious adverse effects. Patients with atrial fibrillation (AF) were studied to clarify this. DESIGN: In the Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation (SPORT