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We suggest a physical picture of the catalytic act combining together the energy transfer and the synchronisation of the best electron density in the reactant and active site as a consecutive sequence of events. Activity and selectivity at molecular level are defined. Geometry requirements seem to be linked to energy and time requirements. Our proposal for developing new catalysts at the molecular
Trilobites from the Middle and Upper Ordovician Andersön Shale Formation in Jämtland, central Sweden, and the Middle Ordovician Killeröd Formation in Skåne (Scania), southern Sweden, are revised and discussed. These formations have several genera and a few species in common, e.g. Botrioides efflorescens (Hadding, 1913a) and Pseudomegalaspis patagiata (Törnquist, 1884). The regional and vertical di
The use of intranasal steroids for the treatment of allergic and vasomotor rhinitis has doubled during the past 5 years. The number of reported cases of nasal septum perforation has increased correspondingly. The mechanism behind this is unknown, and steroid-induced septum perforation is rarely described in the literature. In order to describe the course of events and to form an idea of the extent
In a prospective study on 516 breast cancer patients flow cytometry DNA ploidy and number of cell populations (defined as number of DNA stem lines) detected in the primary tumor were evaluated for prognostic purposes. the median follow-up time was about 5 years. in the 241 node negative cases, those patients with three or more cell populations had the worst prognosis, with a distant recurrence-fre
The alpha-adrenoceptor-mediated contractile effects of noradrenaline (alpha 1 + alpha 2), phenylephrine (alpha 1) and clonidine (alpha 2) on human saphenous veins were investigated in vivo and in vitro. By infusion (0.3 ml min-1) of the drugs (increasing concentrations in the infused solution) into distended (40 mmHg) saphenous veins in six healthy subjects, local vasoconstriction was induced, mea
We analysed and compared the functioning of UV-B screening pigments in plants from marine, fresh water and terrestrial ecosystems, along the evolutionary line of cyanobacteria, unicellular algae, primitive multicellular algae, charophycean algae, lichens, mosses and higher plants, including amphibious macrophytes. Lichens were also included in the study. We were interested in the following key asp
Objective: To see whether there was an increasing incidence of adenocarcinoma of the oesophagus and gastric cardia in the Swedish population. If there is a rising trend and variations in it can be found, could it be explained as a period or cohort phenomenon:? The data were also compared with the incidence of squamous cell carcinoma and gastric cancer with the gastric cardia excluded. Design: Retr
PURPOSE. Structures derived from periocular mesenchyme arise by complex interactions between neural crest and mesoderm. Defects in development or function of structures derived from periocular mesenchyme result in debilitating vision loss, including glaucoma. The determination of long-term fates for neural crest and mesoderm in mammals has been inhibited by the lack of suitable marking systems. In
Aerosol number concentrations in three size ranges (d(p) > 4, d(p) > 12, 18 less than or equal to, dp less than or equal to, 135 nm) and sulfur mass from impactor samples were collected over a total of about 120 sampling hours on 18 long-range commercial flights between the northern mid-latitudes and the equatorial region covering an altitude range between 8.8 and 11.2 km. The data were evaluated
Experimental studies have shown that remodelling of the atrial myocardium is linked to the occurrence and perpetuation of atrial fibrillation (AF). Clinical evidence, however, is insufficient. We recorded monophasic action potentials (MAP) during AF from one to three sites in the right atrium in seven patients with chronic AF (CAF) and in 11 patients with paroxysmal AF (PAF). The fibrillatory (FF)
OBJECTIVE. The aim of the study was to describe the association between clinical risk factors in diabetic patients with food ulcers in relation to outcome. DESIGN. A prospective study of 314 consecutively presenting diabetic patients with foot ulcers referred to the Department of Internal Medicine between July 1, 1983 and June 30, 1987. All patients were followed to final outcome. SETTING. All pat
The pattern of linearly polarized light in the sky can be used for orientation behavior by many insects. Although such behavioral responses have been well described in bees and ants over several decades, until recently it remained largely elusive how polarized-light information is processed in the insect brain. However, over the last decade, substantial advances in understanding polarized- light p
In this article an analytical and empirical model for describing tool life and tool wear in metal cutting is presented. The model is based on combining the Colding tool life equation and an extended version of the Archard wear function. It is shown that through the combining of these two models a substantial saving of resources can be achieved in terms of the workpiece material required, as well a
The co-adsorption of Cd(II) and glyphosate (N-(phosphonomethyl)glycine, PMG) at the manganite (gamma-MnOOH) surface has been studied in the pH range 6-10 at 25 degrees C and with 0.1 M Na(Cl) as ionic medium. Batch adsorption experiments, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine Structure (EXAFS) spectroscopy were use
The morphology and viscoelastic properties of films prepared from bimodal latex blends containing equal weight fractions of soft and hard latex particles were investigated as a function of the particle sizes and the particle size ratio (soft particle diameter/hard particle diameter). Minimum film formation temperature (MFT) measurements were associated with transmission electron microscopy (TEM) t
BACKGROUND: The planning target volume in radiotherapy treatment planning takes into account both movements of the clinical target volume (CTV) and set-up deviations. MATERIALS AND METHODS: A group of patients who received radiotherapy for lung cancer were studied. In order to measure the CTV movements due to respiration and other internal organ motions, fluoroscopy was performed for 20 patients.
Cognitive deficits and impaired olfactory function are observed in early stages of Huntington's disease (HD). The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) is strongly associated with plastic events in the brain. During adulthood, it is most abundantly expressed in the hippocampus and the piriform cortex, which are involved in cognition and olfaction, respectively. We sho
