Search results

Filter

Filetype

Your search for "*" yielded 532974 hits

Aromatic Allylation via Diazotization, Variation of the Allylic Moiety and a Short Route to a Benzazepine Derivative.

A continued study of the recently discovered diazotizative allylation (DiazAll) reaction of aniline derivatives is reported. Several allyl reagents, commonly used in radical allylation reactions, were evaluated, and some of these reagents resulted in allylation when used in the DiazAll reaction. The best result was obtained with allyl bromide. Substituted allylic bromides gave the corresponding al

Interannual and interspecific variation in intensity of the parasitic fly, Philornis downsi, in Darwin’s finches

An integrative approach to managing host–parasite interactions that threaten species communities will benefit from identifying variation in parasite impact across host species, and host–parasite responses to annual climatic variation. We examine interannual, inter- and intraspecific variation in Philornis downsi intensity – an introduced blood sucking fly that causes high fitness costs in Darwin’s

Below-ground responses of silver birch trees exposed to elevated CO2 and O-3 levels during three growing seasons

Field-growing silver birch (Betula pendula Roth) clones (clone 4 and 80) were exposed to elevated CO2 and O-3 in open-top chambers for three consecutive growing seasons (1999-2001). At the beginning of the OTC experiment, all trees were 7 years old. We studied the single and interaction effects of CO2 and O-3 on silver birch below-ground carbon pools (i.e. effects on fine roots and mycorrhizas, so

Characterization of pyrrhotite in Cu-Ni-ore bodies from mines in Botswana by Mossbauer spectroscopy, X-ray diffraction, and thermomagnetometry

Cu-Ni ore bodies from five Botswana mines were investigated, using a combination of X-ray diffraction, thermomagnetic measurements, Mossbauer spectroscopy, and Inductively Coupled Plasma-Atomic Absorption Electro-optic Spectroscopy (ICP-AES). The four dominant phases in the ores were found to be pyrrhotite, magnetite, pentlandite, and chalcopyrite. Mossbauer spectroscopy shows that pyrrhotite is t

High-relaxivity supramolecular aggregates containing peptides and Gd complexes as contrast agents in MRI

Mixed supramolecular aggregates, obtained by assembling together two amphiphilic monomers (C18H37)2NCO(CH2)2CO(AdOO)5-G-CCK8 (AdOO is 8-amino-3,6-dioxaoctanoic acid, CCK8 is C-terminal octapeptide of cholecystokinin) and (C18H37)2NCO(CH2)2COLys(DTPAGlu)CONH2 (DTPAGlu is N,N-bis[2-[bis(carboxyethyl)amino]ethyl]-l-glutamic acid), are characterized for their structural parameters by dynamic light sca

Fouling of electrodialysis membranes by organic substances

In this investigation, the influence of various kinds of organic solutes on the fouling of an anion and a cation selective ED membrane was studied. Fouling by adsorption of organic matter onto the membrane was measured as an increase in the membrane resistance with time. Experiments were performed with a fatty acid (octanoic acid), two anionic surfactants (sodium octanoate and sodium dodecylbenzen

Associations between autoantibodies against apolipoprotein B-100 peptides and vascular complications in patients with type 2 diabetes.

AIMS/HYPOTHESIS: Oxidation of LDL in the arterial extracellular matrix is a key event in the development of atherosclerosis and autoantibodies against oxidised LDL antigens reflect disease severity and the risk of developing acute cardiovascular events. Since type 2 diabetes is associated with increased oxidative stress, we tested the hypothesis that autoantibodies against oxidised LDL antigens ar

Protective effect of low molecular weight heparin on experimental colitis: role of neutrophil recruitment and TNF-alpha production.

OBJECTIVE: The purpose of this study was to examine the impact and mechanism of action of low molecular weight heparin (LMWH) in a model of murine colitis. MATERIALS AND METHODS: Balb/c mice were exposed to 5% dextran sodium sulfate (DSS) in the drinking water for five days. LMWH (500 units/kg/day) was administered by subcutaneous injection prior to and throughout the treatment period with DSS. Cl

Heat transfer enhancement in square ducts with V-shaped ribs

This paper concerns a numerical investigation of the heat and fluid flow in V-shaped ribbed ducts. The Navier-Stokes equations and the energy equation are solved in conjunction with a low Reynolds number k-epsilon turbulence model. The Reynolds turbulent stresses are computed with an explicit algebraic stress model (EASM) while the turbulent heat fluxes are calculated with a simple eddy diffusivit

Elucidation of the phenotypic, functional, and molecular topography of a myeloerythroid progenitor cell hierarchy

The major myeloid blood cell lineages are generated from hematopoietic stem cells by differentiation through a series of increasingly committed progenitor cells. Precise characterization of intermediate progenitors is important for understanding fundamental differentiation processes and a variety of disease states, including leukemia. Here, we evaluated the functional in vitro and in vivo potentia

Backward tilting of the posterior atlantal arch in rheumatoid arthritis

In a retrospective survey of 450 patients with rheumatoid arthritis on whom cervical spine radiography was performed, one patient was found with a backward tilting of the posterior arch of the atlas. With preserved relations anteriorly, the posterior arch was rotated downward in front of the spinous process of the axis, encroaching on the space of the spinal canal.

Hyperfine structure of the ground state in singly ionized manganese

We report the first experimental measurements and theoretical calculations for the hyperfine splitting of the 3d(5) 4s ground state of Mn II. The hyperfine structure constants were determined using Fourier transform spectroscopy with a hollow cathode discharge lamp. The uncertainties in the magnetic dipole constants, A, are between 3 x 10(-4) and 5 x 10(-4) cm(-1). Extensive configuration interact

Acute ethanol exposure attenuates expression of junD in human neuroblastoma cells

This study describes the effects of acute ethanol exposure on the mRNA levels of c-jun,junB and junD in the human neuroblastoma SH-SY5Y cell line. An acute exposure to 100 mM ethanol did not influence the basal and phorbol ester-induced expression of c-jun and junB, whereas the basal mRNA level of junD was attenuated by 30%. This effect was dose- and time-dependent with maximal inhibition being de

A systematic review of the prevalence of Chlamydia trachomatis among European women

The study aim was to establish by systematic review the prevalence of asymptomatic Chlamydia trachomatis infection of the lower female genital tract in Europe and also to assess the extent and effect of screening. The search process was wide ranging, using the electronic databases Medline, Embase and Aidsline and the Internet using the search engines Netscape and Euro-ferret. Studies published in

Self-limited growth of a thin oxide layer on Rh(111)

The oxidation of the Rh(111) surface at oxygen pressures from 10(-10) mbar to 0.5 bar and temperatures between 300 and 900 K has been studied on the atomic scale using a multimethod approach of experimental and theoretical techniques. Oxidation starts at the steps, resulting in a trilayer O-Rh-O surface oxide which, although not thermodynamically stable, prevents further oxidation at intermediate

The hedging performance of electricity futures on the Nordic power exchange

The Nordic Power Exchange (Nord Pool), the first multinational exchange for electricity trading, has existed since January 1996. Spot and futures contracts are traded on this exchange and its typical characteristics are very high volatilities as well as non-normally distributed returns. This article looks at electricity futures and how they can be used for short-term hedging of positions taken in