Nanostructure,composition and magnetic properties in soft and hard Co–Ni nanoparticles: The effect on the magnetic anisotropy

The magnetic properties of Co–Ni alloys nanoparticles with composition Co₈₀Ni₂₀ and Co₅₀Ni₅₀ and dispersed in a silica matrix are investigated. The effective magnetic anisotropies are evaluated from the analysis of the temperature dependence of the zero-field-cooling magnetizations and from the hysteresis loops at 3 K considering the coherent rotation model. The results show that, on the contrary of what expected, Co₈₀Ni₂₀ nanoparticles have smaller anisotropy than the Co₅₀Ni₅₀ one showing that the magnetic properties of the system can be tuned from soft to hard by simply adjusting the alloy composition. This behaviour can be explained on the basis of the different size and composition of the two systems. Moreover we found that the evaluation of the anisotropy constant depends on the experimental method adopted due to the modifications by interparticle dipolar interactions of the reversal process.     

Antiplatelet treatment for thromboprophylaxis: a step forward or backwards?

A recent meta-analysis from the Antiplatelet Trialists'' Collaboration recommended that antilatelet treatment either alone or, for greater effect, in addition to other proved forms of thromboprophylaxis should be considered for patients at high risk of thromboembolism. This paper argues that the current evidence does not justify the adoption of aspirin or other antiplatelet treatment for venous thromboprophylaxis, especially when more effective alternatives exist. Furthermore, several issues relating to this latest meta-analysis need to be debated.     

Klyflaccisteroids K–M,bioactive steroidal derivatives from a soft coral Klyxum flaccidum

New steroids, klyflaccisteroids K–M (1–3), were isolated from a soft coral Klyxum flaccidum. Their structures were elucidated on the basis of extensive spectroscopic analysis. Klyflaccisteroid K (1) is the unique 9,11-secosteroid with a 5,8-epidioxy-9-ene functional group. Klyflaccisteroid L (2) has an unusual 11-norsteroid skeleton and is the first example of 11-oxasteroid isolated from natural sources. Cytotoxicity assay showed that 1 and 3 possessed moderate to weak cytotoxicity against these cancer cells. Compound 1 was also found to display significant anti-inflammatory activity of suppressing superoxide anion generation (O₂^?) and elastase release, and compound 3 was found to show notable anti-inflammatory activity toward inhibition of elasstase release, too.     

Facile synthesis,optical and conformational characteristics,and efficient intracellular delivery of a peptide–DNA conjugate

Covalent conjugation of disparate peptide and oligonucleotide biomacromolecular species produces peptide–oligonucleotide conjugates (POCs), which are interesting molecules with great potential for use in diverse bioapplications. However, peptide–oligonucleotide conjugation methods are not well established, and the intracellular delivery efficacy of POCs is debatable. Here, we describe a simple method for the synthesis and purification of POCs. When peptides are carefully designed to have a near-neutral charge state, a relatively hydrophobic polarity, and receptor-targeting ligands, synthesis and purification become highly efficient and straightforward. UV–vis, fluorescence, and circular dichroism studies show that both types of molecules mutually influence each other, changing their optical and conformational characteristics in the context of POCs. The combined effect of peptide design strategy, targeting ligands, and relatively hydrophobic property, enables the efficient cellular delivery of POCs.     

Phytoplankton: a significant trophic source for soft corals?

Histological autoradiographs and biochemical analyses show that ¹⁴C-labelled microalgae (diatoms, chlorophytes and dinoflagellates) are used by the soft coral Dendronephthya sp. Digestion of the algae took place at the point of exit of the pharynx into the coelenteron. Ingestion and assimilation of the labelled algae depended on incubation time, cell density, and to a lesser extent on species-specificity. ¹⁴C incorporation into polysaccharides, proteins, lipids and compounds of low molecular weight was analysed. The ¹⁴C-labelling patterns of the four classes of substances varied depending on incubation time and cell density. ¹⁴C incorporation was highest into lipids and proteins. Dissolved labelled algal metabolites, released during incubation into the medium, contributed between 4% and 25% to the total ¹⁴C activity incorporated. The incorporated microalgae contributed a maximum of 26% (average of the four species studied) to the daily organic carbon demand, as calculated from assimilation rates at natural eucaryotic phytoplankton densities and a 1 h incubation period. The calculated contribution to the daily organic carbon demand decreased after prolonged incubation periods to about 5% after 3 h and to 1–3% after 9 h. Thus the main energetic demand of Dendronephthya sp. has to be complemented by other components of the seston. Received in revised form: 17 April 2001 Electronic Publication     

P430: a retrospective, 1971–2001

The spectral species P430 and its spectral and kinetic properties are briefly reviewed. Currently available evidence shows P430 to be the optic-spectral representation of FeS-A/B, the electron acceptor(s) of Photosystem I (PS I). Retired (formerly with the Charles F. Kettering Research Laboratory, Yellow Springs, Ohio, USA). This revised version was published online in June 2006 with corrections to the Cover Date.     

The rebound effect through industrial ecology’s eyes: a review of LCA-based studies

Purpose

Industrial ecology academics have embraced with great interest the rebound effect principle operationalised within energy economics. By pursuing more comprehensive assessments, they applied tools such as life cycle assessment (LCA) to appraise the environmental consequences of the rebound effect. As a result, the mainstream rebound mechanism was broadened and a diversity of (sometimes inconsistent) definitions and approaches unveiled. To depict the state of play, a comprehensive literature review is needed.

Methods

A literature review has been carried out by targeting scientific documents relevant for the integration of the rebound effect into LCA-based studies. The search was conducted using two approaches: (1) via online catalogues using a defined search criterion and (2) via cross-citation analysis from the documents identified through the first approach.

Results and discussion

By analysing a total of 42 works yielded during our review, it was possible to bring together the various advantages of the life cycle perspective, as well as to identify the main inconsistencies and uninformed claims present in literature. Concretely, three main advantages have been identified and are discussed: (1) the representation of the rebound effect as a multi-dimensional, life cycle estimate, (2) the improvement of the technology explicitness and (3) the broadening of the consumption and production factors leading to the rebound effect. Also, inconsistencies on the definition and classification of the rebound effect have been found among studies.

Conclusions

The review contributes a number of valuable insights to understand how the rebound effect has been treated within the industrial ecology and LCA fields. For instance, the conceptual and methodological refinements introduced by these fields represent a step forward from traditional viewpoints, making the study of the rebound effect more comprehensive and meaningful for environmental assessment and policy making. However, the broadened scope of this new approach unveiled some conceptual inconsistencies, which calls for a common framework. This framework would help the LCA community to consistently integrate the rebound effect as well as to create a common language with other disciplines, favouring learning and co-evolution. We believe that our findings can serve as a starting point in order to delineate such a common framework.     

“More drugs,less crime”: why crime dropped in New York City, 1985–2007

The crime drop in New York City has produced a whole academic literature that is unable to explain the decline. This article argues that this literature has ignored the simplest explanation of all: a simultaneous increase in the supply, and decrease in demand for illegal drugs led to a drop in the price of illegal drugs, which in turn led to a drop in crime. We use ethnography to document the drop in demand, secondary literature to document the increase in supply, and econometric analysis to illustrate Granger causality between drug prices and crime rates. While crime dropped across the nation and internationally, our article is focused on New York City.     

Would a medium-nicotine,low-tar cigarette be less hazardous to health?

Smoking behaviour and exposure to carbon monoxide, nicotine, and tar were studied in 19 middle-tar smokers. All smoked their own brands for three weeks and then switched to either a conventional low-nicotine, low-tar brand (control) or a medium-nicotine, low-tar cigarette for a further three weeks, the order then being reversed. The medium-nicotine, low-tar brand also had a low delivery of carbon monoxide. With the medium-nicotine, low-tar cigarette mouth-level delivery and intake of nicotine was similar to that with the smokers'' usual brands, and significantly greater than with the control low-tar cigarette. Intake of carbon monoxide from the medium-nicotine, low-tar cigarette was significantly less than with either own or control brands. With both low-tar brands mouth-level exposure to tar was reduced relative to smokers'' usual cigarettes. There was no evidence, however, that the reduction in tar exposure was greater with the medium-nicotine brand than with the control low-tar cigarette. Both low tar brands were ''oversmoked relative to subjects'' usual middle-tar cigarettes. The medium-nicotine, low-tar cigarette was marginally more acceptable than the control brand, and the particular design used in the study resulted in a lower intake of carbon monoxide. In terms of reducing mouth-level exposure to tar, however, the medium-nicotine, low-tar cigarette had no advantage over the control low-tar product. In part this was because of the ratio of tar to nicotine delivery obtained by human smokers was not the same as that obtained by smoking machine.     

Roger Yate Stanier, 1916–1982: a transcendent journey

The Tenth International Symposium on Phototrophic Prokaryotes (Barcelona, 26-31 August 2000) was the latest in a series of conferences initiated by Roger Stanier in 1971 to create ties within the community of scientists working with cyanobacteria or green and purple bacteria. Consonant with Stanier's own work, the subjects of these conferences range broadly from systematics and ecology through genetics, biochemistry and physiology. The effort to define comprehensively the place of bacteria in the living world was the leitmotif in Stanier's work, the subject of one of his earliest papers (in 1941), and revisited for the final time in his autobiographical memoir of 1980. Salvador Luria noted that Stanier "...always pursued broad naturalistic interests along with chemical ones, deliberately emphasizing morphology and ecology side by side with biochemistry." Chronologically, Stanier's work addressed taxonomic and nutritional aspects of the cytophagas, enzyme induction and patterns of regulation of enzyme synthesis, aromatic degradative pathways, characterization of what would subsequently be called 70S bacterial ribosomes, the regulation of bacteriochlorophyll synthesis by nonsulfur purple bacteria, protection by carotenoids against photooxidative damage, the path of carbon in heterotrophy, the molecular basis of streptomycin dependence, the life cycle of Caulobacter, the taxonomy of pseudomonads, and, for the last 12 years of his life, wide-ranging studies of the cyanobacteria.     

Caseoperoxidase,mixed β-casein–SDS–hemin–imidazole complex: a nano artificial enzyme

A novel peroxidase-like artificial enzyme, named “caseoperoxidase”, was biomimetically designed using a nano artificial amino acid apo-protein hydrophobic pocket. This four-component nano artificial enzyme containing heme–imidazole–β-casein–SDS exhibited high activity growth and k_cat performance toward the native horseradish peroxidase demonstrated by the steady state kinetics using UV–vis spectrophotometry. The hydrophobicity and secondary structure of the caseoperoxidase were studied by ANS fluorescence and circular dichroism spectroscopy. Camel β-casein (Cβ-casein) was selected as an appropriate apo-protein for the heme active site because of its innate flexibility and exalted hydrophobicity. This selection was confirmed by homology modeling method. Heme docking into the newly obtained Cβ-casein structure indicated one heme was mainly incorporated with Cβ-casein. The presence of a main electrostatic site for the active site in the Cβ-casein was also confirmed by experimental methods through Wyman binding potential and isothermal titration calorimetry. The existence of Cβ-casein protein in this biocatalyst lowered the suicide inactivation and provided a suitable protective role for the heme active-site. Additional experiments confirmed the retention of caseoperoxidase structure and function as an artificial enzyme.     

Hamsters Running on Time: Is the Lateral Habenula a Part of the Clock?

Previous anatomical and physiological studies have implicated the lateral habenula, and especially its medial division (LHbM), as a candidate component of the circadian timing system in rodents. We assayed lateral habenula rhythmicity in rodents using c‐FOS immunohistochemistry and found a robust rhythm in immunoreactive cell counts in the LHbM, with higher counts during the dark phase of a light‐dark (LD) cycle and during subjective night in constant darkness. We have also observed an obvious asymmetry of c‐FOS expression in the LHbM of behaviorally “split” hamsters in constant light, but only during their active phase (when they were running in wheels). Locomotor activity rhythms appear to be regulated by the suprachiasmatic nucleus (SCN) via multiple output pathways, one of which might be diffusible while the other might be neural, involving the lateral habenula.