Sökresultat

Filtyp

Din sökning på "*" gav 527856 sökträffar

A femtosecond X-ray/optical cross-correlator

For a fundamental understanding of ultrafast dynamics in chemistry, biology and materials science it has been a long-standing dream to record a molecular movie in which both the atomic trajectories and the chemical states of every atom in matter are followed in real time(1). Free- electron lasers provide this perspective as they deliver brilliant femtosecond X-ray pulses spanning a wide photon ene

Clinical characteristics and biological parameters in temperamental clusters of suicide attempters

A sample of 215 suicide attempters was categorized in a cluster analysis into four groups according to temperamental trails. Monoamine metabolites in the cerebrospinal fluid were analysed (n = 106). Dexamethasone suppression tests (DST) were performed (n = 154) and the activity of the enzyme monoamine oxidase in platelets (pl-MAO) was assessed (n = 103). Patients belonging to the two clusters with

ST-recovery loop of exercise-induced ST deviation in the identification of coronary artery disease: Which parameters should we measure?

This study aimed to characterize the ST-recovery loop and assess which range of heart rates (HRs) best discriminates between patients with and without significant coronary artery stenosis. Bicycle exercise tests were undertaken in 44 men and IS women with coronary artery disease (CAD) and in 59 controls (26 men, 33 women) in the same age range with no signs of CAD. The ST level and the ST-segment

Local vega index and variance reduction methods

In this article we discuss a generalization of the Greek called vega which is used to study the stability of option prices and hedging portfolios with respect to the volatility in various models. We call this generalization the local vega index. We compute through Monte Carlo simulations this index in the cases of Asian options under the classical Black-Scholes setup. Simulation methods using Mall

Male coloration reveals different components of immunocompetence in ostriches, Struthio camelus

It has been suggested that secondary sexual ornamentation signals male ability to resist infections, as only high-quality individuals are able to invest both in high immune defence and elaborate ornament expression. Such ornaments could thus serve as indicators of male quality and could be used by females in choosing mates. Ostriches are sexually dimorphic with regard to coloration of their feathe

Cancer incidence in 13811 patients skin tested for allergy

Aim. Several studies have shown a negative correlation between cancer and atopy-related diseases. There are also a few reports of a positive relationship. We wanted to further evaluate these relationships in a prospective study. Subjects and methods. The incidence of malignant diseases among adult patients with atopy-related diseases (asthma, rhinitis, urticaria, eczema etc; n=13811), who had been

Aromatic O-glycosylation

Carbohydrates carrying an aromatic aglycon are important natural products and thus key synthetic targets. However, due to the electron-withdrawing properties of aromatic rings, phenols are difficult to glycosylate. This review covers the most common carbohydrate donors used for aromatic O-glycosylation (anomeric acetates, halides, trichloroacetimidates and thioglycosides) as well as some less comm

Nanoparticle-based pseudostationary phases in capillary electrochromatography.

During the past decades, research has been performed to enhance selectivity in CE by introducing different types of additives into the electrolyte. Research concerning this has taken many directions, especially during the last 5 years. A promising technique, which benefits from no packing or frits, is to use nanoparticles as the pseudostationary phase (PSP) in CEC. PSPs have the advantage of intro

Endemism Predicts Intrinsic Vulnerability to Nonindigenous Species on Islands.

Abstract: While numerous efforts have been made to identify and quantify factors controlling invasibility of biological communities, less attention has been given to analyzing the expressions of vulnerability to nonindigenous species (NIS). Using the International Union for the Conservation of Nature and Natural Resources Red List database for birds, mammals, and amphibians and the Invasive Specie

Colour perception in a dichromat

Most mammals have dichromatic colour vision based on two different types of cones: a short-wavelength-sensitive cone and a long-wavelength-sensitive cone. Comparing the signal from two cone types gives rise to a one-dimensional chromatic space when brightness is excluded. The so-called ‘neutral point’ refers to the wavelength that the animal cannot distinguish from achromatic light such as white o

An integrated palaeoenvironmental investigation of a 6200 year old peat sequence from Ile de la Possession, Iles Crozet, sub-Antarctica

A 6200 year old peat sequence, cored in a volcanic crater on the sub-Antarctic Ile de la Possession (Iles Crozet), has been investigated, based on a multi-proxy approach. The methods applied are macrobotanical (mosses, seeds and fruits) and diatom analyses, complemented by geochemical (Rock-Eval6) and rock magnetic measurements. The chronology of the core is based on 5 radiocarbon dates. When comb

A reevaluation of the validity of unrestrained plethysmography in mice

Presently, unrestrained plethysmography is widely used to assess bronchial responsiveness in mice. An empirical quantity known as enhanced pause is derived from the plethysmographic box pressure [P-b( t), where t is time] and assumed to be an index of bronchoconstriction. We show that P-b(t) is determined largely by gas conditioning when normal mice breathe spontaneously inside a closed chamber in

Initiation of the decorin glycosaminoglycan chain in the endoplasmic reticulum-Golgi intermediate compartment

We have transiently expressed decorin with a C- terminal KDEL endoplasmic reticulum retention signal peptide in COS- 7 cells to study initiation of galactosaminoglycan synthesis in the endoplasmic reticulum- Golgi intermediate compartment. All decorin- KDEL molecules were substituted with N- linked oligosaccharides sensitive to endoglycosidase H, indicating that the core protein was located proxim