Sökresultat

The acidity and basicity of prereduced V-Ti-O catalysts were measured by adsorption of NH3 and CO2. It was found that a high activity in the ammoxidation of 3-picoline corresponds to a relatively small amount of acidic sites. A catalyst selective in the formation of nicotinonitrile requires high concentrations of both acidic and basic sites. These results are discussed, and can be correlated if th

Three aspects on nanocantilevers are presented in this letter. First, we present the fabrication process of 2 mum long freestanding chromium cantilevers with width 150 nm, and thickness 50 nm. Second, a measurement scheme using an atomic force microscope operating in contact mode was employed to study the mechanical properties along the length of the cantilevers. Third, we have investigated extrem

We show how to find series expansions for pi of the form pi = Sigma(n=0)(infinity) S(n)/((mn)(pn)) a(n), is some polynomial in n (depending on m,p,a). We prove that there exist such expansions for m = 8k, p = 4k, a = (-4)(k), for any k, and give explicit examples for such expansions for small values of m, p and a.

Direct and inverse scattering from dispersive media are studied in the time domain. The media are one-dimensional and homogeneous but can be impedance mismatched to the surrounding media. A time-domain method is introduced where the reflection and transmission kernels are obtained from Volterra equations of the second kind. Numerical examples are given based upon both synthetic and measured data f

Hospitalized patients have a right to be assessed for pain and receive optimal pain management, but inadequate pain management is still widely prevalent. Different quality improvement (QI) approaches have been used to improve patients’ experience of pain, with varied results. The aim of this study was to implement a QI program and evaluate its effects on pain management routines in acute care, exp

Autoxidation of five flavonoids representing range of different hydrophilicities (epicatechin gallate (ECG), (+) catechin((+)Q, epicatechin (EC), epigallocatechin gallate (EGCG) and epigallocatechin (EGC)) in three different aqueous solutions: molecular solution, micellar solution (Tween 20) and liposoml dispersion (soybean lecithin) was monitored by HPLC. The rate of oxidaton of the five flvonoid

We present a Monte Carlo study of a model protein with 54 amino acids that folds directly to its native three-helix-bundle state without forming any well-defined intermediate state. The free-energy barrier separating the native and unfolded states of this protein is found to be weak, even at the folding temperature. Nevertheless, we find that melting curves to a good approximation can be described

Traditional explanations for the negative fitness consequences of parasitism have focused on the direct pathogenic effects of infectious agents. However, because of the high selection pressure by the parasites, immune defences are likely to be costly and trade off with other fitness-related traits, such as reproductive effort. In a field experiment, we immunized breeding female flycatchers with no

Purpose Earlier studies have shown that endogenous gonadal hormones play an important role in the etiology of breast cancer among BRCA1/ 2 mutation carriers. So far, little is known about the safety of exogenous hormonal use in mutation carriers. In this study, we examined the association between oral contraceptive use and risk of breast cancer among BRCA1/ 2 carriers. Patients and Methods In the

Intradialytic hypotension (IDH) is one of the most important short-term complications to hemodialysis (HD). Inadequate cardiac filling due to a reduction in the central blood volume is believed to be a major etiological factor. The aim of this study was to evaluate whether these pathophysiologic events are reflected in the central venous oxygen saturation (ScO2) and thoracic admittance (TA) during

The concept of sustainable development at present permeates public discourse. An inter-organisational perspective can be used to analyse the processes through which this concept has found its way into policy and programme in four different settings: the United Nations, the European Communities, the government of Sweden and the city of Lund, Sweden. Although visible in treaties, laws and action pro

Molecularly imprinted nanoparticles are cross-linked polymer colloids containing tailor-made molecular recognition sites. In this study, molecularly imprinted nanoparticles were easily encapsulated within polymer nanofibers using an electrospinning technique to produce a new type of molecular recognition material. Poly(ethylene terephthalate) (PET) was used as the supporting nanofibers matrix to e

It has been proposed that lack of social support in a work place characterized by high levels of stress, may increase the likelihood of future cardiovascular disease. The aim of this study was to analyze the prospective impact of social support at work in combination with self-reported work stress on incidence of myocardial infarction (MI) and stroke in a cohort of 4707 women (mean age: 54.2 years

We present a study of Young's modulus of epitaxially grown InAs nanowires with diameters from 40 to 95 nm. The dynamic behavior of the nanowires is investigated using optical stroboscopic imaging. The Young's modulus, evaluated using the eigenfrequencies of the fundamental and the first excited modes in air, decreases for smaller diameters. To avoid the influence of the electric field on the reson

The Pegomya meridiana species group is established for three Palaearctic species that supposedly all as larvae attack seed-capsules of Hypericum spp. (Clusiaceae). Pegomya meridiana (Villeneuve) and P. provecta (Villeneuve) are widespread Eurasian species, while the third species, P. canariensis Michelsen, is endemic to the western Canary Islands. Synapomorphies for the Pegomya meridiana species g