Magnetoresistance and surface roughness study of the initial growth of electrodeposited Co/Cu multilayers

The giant magnetoresistance (GMR) effect has been widely investigated on electrodeposited ferromagnetic/non-magnetic (FM/NM) multilayers generally containing a large number of bilayers. In most applications of the GMR effect, layered structures consisting of a relatively small number of consecutive FM and NM layers are used. It is of great interest, therefore, to investigate the initial stages of GMR multilayer film growth by electrodeposition. In the present work we have extended our previous studies on ED GMR multilayers to layered structures with a total thickness ranging from a few nanometers up to 70 nm. The evolution of the surface roughness and electrical transport properties of such ultrathin ED Co/Cu layered structures was investigated. Various layer combinations were produced including both Co and Cu either as starting or top layers in order (i) to see differences in the nucleation of the first layer and (ii) to trace out the effect of the so called exchange reaction. Special attention was paid to measure the field dependence of the magnetoresistance, MR(H) in order to derive information for the appearance of superparamagnetic regions in the magnetic layers. This proved to be helpful for monitoring the evolution of the layer microstructure at each step of the deposition sequence

Is degree of sociality associated with reproductive senescence? A comparative analysis across birds and mammals

Our understanding on how widespread reproductive senescence is in the w ild and how the onset and rate of reproductive senescence vary among species in relation to life histories and lifestyles is currently limited. More specifically, whether the species-specific degree of sociality is linked to the occurrence, onset and rate of reproductive senescence remains unknown. Here, we investigate these questions using phylogenetic comparative analyses across 36 bird and 101 mammal species encompassing a wide array of life histories, lifestyles and social traits. We found that female reproductive senescence (1) is widespread and occurs with similar frequency (about two thirds) in birds and mammals; (2) occurs later in life and is slower in birds than in similar-sized mammals; (3) occurs later in life and is lower with an increasingly slower pace of life in both vertebrate classes; and (4) is only weakly associated, if any, with the degree of sociality in both classes after accounting for the effect of body size and pace of life. However, when removing the effect of species differences in pace of life, a higher degree of sociality was associated with later and weaker reproductive senescence in females, which suggests that degree of sociality is either indirectly related to reproductive senescence via the pace of life or simply a direct outcome of the pace of life

Gold-Catalyzed Direct Alkynylation of Azulenes

A novel catalytic method for the direct C–H alkynylation of azulenes is developed. The gold catalyzed functionalization of this special carbacycle is achieved with hypervalent iodonium reagent TIPS-EBX under mild reaction conditions. With the aid of the developed procedure, several TIPS alkynylated azulene derivatives were synthesized bearing important functional groups for further functionalization

Visual Detection of DNA on Paper Chips

On-site DNA analysis for diagnostic or forensic purposes is much anticipated in the future of molecular testing. Yet the challenges to achieve this goal remain large with rapid and inexpensive detection and visualization being key factors for any portable analysis system. We have developed a filter paper-based nucleic acid assay, which is able to identify and distinguish dog and human genomic and mitochondrial samples in a forensic setting. The filter paper material allows for transport by capillary force of the sample DNA through the detection surface, allowing the targets to hybridize specifically to their complementary capture sequences. Coupling micrometer-sized beads to DNA allows the results to be visualized by the naked eye, enabling instant, cost-efficient, and on-site detection, while eliminating the need for advanced expensive instrumentation

Effects of Organic and Conventional Crop Nutrition on Profiles of Polar Metabolites in Grain of Wheat

The profiles of polar metabolites were determined in wholemeal flours of grain from the Broadbalk wheat experiment and from plants grown under organic and low-input systems to study the effects of nutrition on composition. The Broadbalk samples showed increased amino acids, acetate, and choline and decreased fructose and succinate with increasing nitrogen fertilization. Samples receiving farm yard manure had similar grain nitrogen to those receiving 96 kg of N/ha but had higher contents of amino acids, sugars, and organic acids. A comparison of the profiles of grain from organic and low-input systems showed only partial separation, with clear effects of climate and agronomy. However, supervised multivariate analysis showed that the low-input samples had higher contents of many amino acids, raffinose, glucose, organic acids, and choline and lower sucrose, fructose, and glycine. Consequently, although differences between organic and conventional grain occur, these cannot be used to confirm sample identity

Silica-Based Catalyst Supports Are Inert, Are They Not?: Striking Differences in Ethanol Decomposition Reaction Originated from Meso- and Surface-Fine-Structure Evidenced by Small-Angle X‑ray Scattering

6.6 nm Pt nanoparticles with narrow size distribution were anchored on mostly identical, amorphous silica supports (SBA-15, MCF-17, silica foam) and were tested in ethanol decomposition reactions at <300 °C. The reaction on the Pt/SBA-15 was ∼2 times faster (0.073 molecules·site^–1·s^–1) compared with Pt/MCF-17 (0.042 molecules·site^–1·s^–1) and Pt/SF (0.040 molecules·site^–1·s^–1) at 300 °C. In the case of Pt/SF, selectivity toward acetaldehyde was ∼2 times higher compared with the Pt/MCF-17 and Pt/SBA-15 catalysts. In the case of Pt/MCF-17 and Pt/SBA-15, the methane to acetaldehyde ratio was ∼4 times higher compared with the Pt/SF catalyst. The ethene selectivity was ∼1.5 times higher in the case of Pt/SBA-15 compared with Pt/MCF-17 and Pt/SF. Small-angle X-ray scattering (SAXS) studies showed striking differences in the nature of the surface of the different silica supports, which may be responsible for the activation and selectivity deviation in ethanol decomposition reactions. The SBA-15 has the most disordered mesostructure, and SF has a fine surface structure with a diffuse phase boundary, which may result in the high activity and varying selectivity, respectively

Novel Arylalkenylpropargylamines as Neuroprotective, Potent, and Selective Monoamine Oxidase B Inhibitors for the Treatment of Parkinson’s Disease

To develop novel neuroprotective agents, a library of novel arylalkenylpropargylamines was synthesized and tested for inhibitory activities against monoamine oxidases. From this, a number of highly potent and selective monoamine oxidase B inhibitors were identified. Selected compounds were also tested for neuroprotection in in vitro studies with PC-12 cells treated with 6-OHDA and rotenone, respectively. It was observed that some of the compounds tested yielded a marked increase in survival in PC-12 cells treated with the neurotoxins. This indicates that these propargylamines are able to confer protection against the effects of the toxins and may also be considered as novel disease-modifying anti-Parkinsonian agents, which are much needed for the therapy of Parkinson’s disease