Recovering Bioactive Compounds from Olive Oil Filter Cake by Advanced Extraction Techniques

The potential of by-products generated during extra-virgin olive oil (EVOO) filtration as a natural source of phenolic compounds (with demonstrated bioactivity) has been evaluated using pressurized liquid extraction (PLE) and considering mixtures of two GRAS (generally recognized as safe) solvents (ethanol and water) at temperatures ranging from 40 to 175 °C. The extracts were characterized by high-performance liquid chromatography (HPLC) coupled to diode array detection (DAD) and electrospray time-of-flight mass spectrometry (HPLC-DAD-ESI-TOF/MS) to determine the phenolic-composition of the filter cake. The best isolation procedure to extract the phenolic fraction from the filter cake was accomplished using ethanol and water (50:50, v/v) at 120 °C. The main phenolic compounds identified in the samples were characterized as phenolic alcohols or derivatives (hydroxytyrosol and its oxidation product), secoiridoids (decarboxymethylated and hydroxylated forms of oleuropein and ligstroside aglycones), flavones (luteolin and apigenin) and elenolic acid derivatives. The PLE extraction process can be applied to produce enriched extracts with applications as bioactive food ingredients, as well as nutraceuticals.     

Spatial model selection strategies in a SUR framework. The case of regional productivity in EU

The purpose of the paper was to compare two well-known model selection strategies, the so-called Specific-to-General, Stge, and General-to-Specific, Gets, in a context of spatial SUR models. The two strategies use a battery of misspecification tests obtained in a maximum likelihood framework. The robust tests to local misspecification errors in the alternative hypothesis and the common factor test have been developed with this purpose. The paper includes a Monte Carlo experiment to compare their performance in a situation of small sample sizes. The results are mixed: Both alternatives work well under ideal conditions, but their efficiency deteriorates for different departures such as non-normality or endogeneity. All in all, Stge appears to be slightly preferable although our impression is that the two are complementary and can be used in common. The paper finishes with an application to the case of productivity for a large set of European regions.     

Determinants of success for biomedical researchers: a perception-based study in a health science research environment

New institutions are coming to the fore as stakeholders in research, particularly hospitals and clinical departments involved in providing health care. As a result, new environments for research are gaining importance. This study aims to investigate how different individual characteristics, together with collective and contextual factors, affect the activity and performance of researchers in the particular setting of hospitals and research centres affiliated with the Spanish National Health System (NHS). We used a combination of quantitative science indicators and perception-based data obtained through a survey of researchers working at NHS hospitals and research centres. Inbreeding and involvement in clinical research is the combination of factors with the greatest influence on scientific productivity, because these factors are associated with increased scientific output both overall as well as in high-impact journals. Ultimately, however, satisfaction with human resources in research group combined with gender (linked in turn to leadership) is the combination of factors associated most clearly with the most relevant indicator of productivity success, i.e. the number of articles in high-impact journals as principal author. Researchers’ competitiveness in obtaining research funding as principal investigator is associated with a combination of satisfaction with research autonomy and involvement in clinical research. Researchers’ success is not significantly related with their age, seniority and international experience. The way health care institutions manage and combine the factors likely to influence research may be critical for the development and maintenance of research-conducive environments, and ultimately for the success of research carried out in hospitals and other settings within the national public health system.     

Effect on the journal impact factor of the number and document type of citing records: a wide-scale study

We studied the effect on journal impact factors (JIF) of citations from documents labeled as articles and reviews (usually peer reviewed) versus citations coming from other documents. In addition, we studied the effect on JIF of the number of citing records. This number is usually different from the number of citations. We selected a set of 700 journals indexed in the SCI section of JCR that receive a low number of citations. The reason for this choice is that in these instances some citations may have a greater impact on the JIF than in more highly-cited journals. After excluding some journals for different reasons, our sample consisted of 674 journals. We obtained data on citations that contributed to the JIF for the years 1998?C2006. In general, we found that most journals obtained citations that contribute to the impact factor from documents labeled as articles and reviews. In addition, in most of journals the ratio between citations that contributed to the impact factor and citing records was greater than 80% in all years. Thus, in general, we did not find evidence that citations that contributed to the impact factor were dependent on non-peer reviewed documents or only a few citing records.     

Biodegradation of sulfamethazine by Trametes versicolor: Removal from sewage sludge and identification of intermediate products by UPLC-QqTOF-MS

Degradation of the sulfonamide sulfamethazine (SMZ) by the white-rot fungus Trametes versicolor was assessed. Elimination was achieved to nearly undetectable levels after 20 h in liquid medium when SMZ was added at 9 mg L^− 1. Experiments with purified laccase and laccase-mediators resulted in almost complete removal. On the other hand, inhibition of SMZ degradation was observed when piperonilbutoxide, a cytochrome P450-inhibitor, was added to the fungal cultures. UPLC-QqTOF-MS analysis allowed the identification and confirmation of 4 different SMZ degradation intermediates produced by fungal cultures or purified laccase: desulfo-SMZ, N⁴-formyl-SMZ, N⁴-hydroxy-SMZ and desamino-SMZ; nonetheless SMZ mineralization was not demonstrated with the isotopically labeled sulfamethazine-phenyl-¹³C₆ after 7 days. Inoculation of T. versicolor to sterilized sewage sludge in solid-phase systems showed complete elimination of SMZ and also of other sulfonamides (sulfapyridine, sulfathiazole) at real environmental concentrations, making this fungus an interesting candidate for further remediation research.     

Deriving the W-matrix via p-median complete correlation analysis of residuals

Most W-matrices are built on the basis of some metric or distance measure; this paper proposes correlation coefficients as a measure of proximity. The method is applied to the case of Belgium regional data and a small Monte Carlo confirms its utility.     

Evidence of Oxygen Ferromagnetism in ZnO Based Materials

Discoveries of room‐temperature ferromagnetism (RTFM) in semiconductors hold great promise in future spintronics technologies. Unfortunately, this ferromagnetism remains poorly understood and the debate concerning the nature, carrier‐mediated versus defect‐mediated, of this ferromagnetism in semiconducting oxides is still open. Here, by using X‐ray absorption (XAS) and X‐ray magnetic circular dichroism (XMCD), it is demonstrated that the oxygen ions have a ferromagnetic response in different ZnO‐based compounds showing RTFM behavior: ZnO nanoparticles capped with organic molecules and ZnO/ZnS heterostructures. These results demonstrate the intrinsic occurrence of RTFM in these systems, and point out that it is not related to the metallic cation but it relays on the conduction band of the semiconductor.