Promoting Sustainable Food Consumption: An Agent-Based Model About Outcomes of Small Shop Openings

A useful way of promoting sustainable food consumption is to consider the spread of food retail operations focused on food diversification, food specialization, and fresh and local products. These food shops are generally small, which is a great problem for survival against ruthless competition from supermarkets. Our research objective was to construct a simulation with an agent-based model, reproducing the local food consumption market and to investigate how a new, small food retailing shop interacts with this market. As a case study, the model simulates the opening of a small farmers' market. The intent of the model is to reproduce the current status of consumption for food products within a certain territorial context and given time period, and to investigate how consumers' behaviour changes with the opening of the new shop. As a result, we could predict changes in consumers' habits, the economic positioning of new, small shops and its best location. This information is of considerable interest for farmers' markets and also for policymakers

Characterization of nanometer-sized, mechanically exfoliated graphene on the H-passivated Si(100) surface using scanning tunnelling microscopy

We have developed a method for depositing graphene monolayers and bilayers with minimum lateral dimensions of 2-10 nm by the mechanical exfoliation of graphite onto the Si(100)-2x1:H surface. Room temperature, ultra-high vacuum (UHV) tunnelling spectroscopy measurements of nanometer-sized single-layer graphene reveal a size dependent energy gap ranging from 0.1-1 eV. Furthermore, the number of graphene layers can be directly determined from scanning tunnelling microscopy (STM) topographic contours. This atomistic study provides an experimental basis for probing the electronic structure of nanometer-sized graphene which can assist the development of graphene-based nanoelectronics.Comment: Accepted for publication in Nanotechnolog

Two-Stage Two-Locus Models in Genome-Wide Association

Studies in model organisms suggest that epistasis may play an important role in the etiology of complex diseases and traits in humans. With the era of large-scale genome-wide association studies fast approaching, it is important to quantify whether it will be possible to detect interacting loci using realistic sample sizes in humans and to what extent undetected epistasis will adversely affect power to detect association when single-locus approaches are employed. We therefore investigated the power to detect association for an extensive range of two-locus quantitative trait models that incorporated varying degrees of epistasis. We compared the power to detect association using a single-locus model that ignored interaction effects, a full two-locus model that allowed for interactions, and, most important, two two-stage strategies whereby a subset of loci initially identified using single-locus tests were analyzed using the full two-locus model. Despite the penalty introduced by multiple testing, fitting the full two-locus model performed better than single-locus tests for many of the situations considered, particularly when compared with attempts to detect both individual loci. Using a two-stage strategy reduced the computational burden associated with performing an exhaustive two-locus search across the genome but was not as powerful as the exhaustive search when loci interacted. Two-stage approaches also increased the risk of missing interacting loci that contributed little effect at the margins. Based on our extensive simulations, our results suggest that an exhaustive search involving all pairwise combinations of markers across the genome might provide a useful complement to single-locus scans in identifying interacting loci that contribute to moderate proportions of the phenotypic variance

Aluminum(III) Salen Complexes as Active Photoredox Catalysts

Metallosalen are privileged complexes that have found important applications in catalysis. In addition, their luminescent properties have also been studied and used for sensing and biological applications. Salen metal complexes can be efficient photosensitizers, but they can also participate to electron transfer processes. Indeed, we have found that commercially available [Al(Salen)Cl] is an efficient photoredox catalyst for the synergistic stereoselective reaction of alkyl aldehydes with different bromo ketones and malonates to give the corresponding enantioenriched α-alkylated derivatives. The reaction was performed in the presence of a MacMillan catalyst. [Al(Salen)Cl] is able to replace ruthenium complexes, showing that also aluminum complexes can be used in promoting photoredox catalytic reactions

Unit cell of graphene on Ru(0001): a 25 x 25 supercell with 1250 carbon atoms

The structure of a single layer of graphene on Ru(0001) has been studied using surface x-ray diffraction. A surprising superstructure has been determined, whereby 25 x 25 graphene unit cells lie on 23 x 23 unit cells of Ru. Each supercell contains 2 x 2 crystallographically inequivalent subcells caused by corrugation. Strong intensity oscillations in the superstructure rods demonstrate that the Ru substrate is also significantly corrugated down to several monolayers, and that the bonding between graphene and Ru is strong and cannot be caused by van der Waals bonds. Charge transfer from the Ru substrate to the graphene expands and weakens the C-C bonds, which helps accommodate the in-plane tensile stress. The elucidation of this superstructure provides important information in the potential application of graphene as a template for nanocluster arrays.Comment: 9 pages, 3 figures, paper submitted to peer reviewed journa

Copper deficiency anemia after bariatric surgery

Copper is a trace mineral essential to hematopoiesis and to the structure and function of the nervous system. Copper acts as a ligand to ferroxidase II, which oxidizes iron, allowing it to be mobilized and transported from the hepatic stores to the bone marrow to be used in erythropoiesis..Copper deficiency is a rare cause of anemia, leukopenia, and myeloneuropathy. In this report we describe a case of a 49 year-old overweight Caucasian woman who was referred June 2008 to the Obesity Outpatient Clinic at UNIFESP for evaluation of muscular pain and weakness in both legs, fatigue and chronic anemia. The past medical history included Scopinaro Surgery for severe obesity in November 2004 when her weight was approximately 180 Kg (BMI 68.6 kg/m2). She lost considerable weight after surgery, with her weight being stable around 80 kg (BMI 30). Because of clinical manifestations of sub nutrition, protein and vitamin deficiencies and severe anemia, which lead to several hospital admissions, in February 2008 she was submitted to another surgery from conversion of the gastrointestinal surgical Scopinaro procedure to that performed by Capella. She also had a history of hypothyroidism, hyperuricemia and panic syndrome, requiring specific medications, beyond parenteral iron and B12 vitamin therapies for anemia. Physical examination revealed a bilateral edema and no other abnormality. Laboratory tests revealed hypoalbuminemia and hypochromic megaloblastic anemia with normal serum levels of B12 vitamin, iron and ferritin. Due to the persistence of the neurologic symptoms and anemia in spite of adequate iron and B12 vitamin therapies, the hypothesis of copper deficiency was considered and a low serum level of 40μg/dl was found. An oral supplementation with high doses of copper resulted in evident clinical and laboratorial improvements after eight weeks of therapy. The diagnosis of copper deficiency has to be part of the differential diagnosis in patients with unexplained neurologic symptoms, anemia, and leukopenia, especially in those who underwent to previous gastrointestinal surgery

Synthesis, Structure, Photophysics, and Singlet Oxygen Sensitization by a Platinum(II) Complex of Meso-Tetra-Acenaphthyl Porphyrin

A new platinum(II) porphyrin complex has been synthesized and characterized via various spectroscopic techniques. Single-crystal XRD analysis reveals that the geometry around the Pt(II) center is near the perfect square planar geometry. The Pt(II)−N bond distances are in the ranges of 2.005 Å–2.020 Å. The platinum(II) porphyrin derivative exhibited one reversible oxidative couple at +1.10 V and a reversible reductive couple at −1.47 V versus Ag/AgCl. In deaerated dichloromethane solution at 298 K, a strong phosphorescence is observed at 660 nm, with emission quantum yield of 35 % and lifetime of 75 μs. Upon excitation of the acenaphthene chromophores at 300 nm, sensitised phosphorescence of the Pt(II) porphyrin is observed with a unitary efficient energy transfer, demonstrating that this system behaves as a light harvesting antenna. The red phosphorescence is strongly quenched by oxygen, resulting in singlet oxygen production with a very high quantum yield of 88 %. This result indicates that this Pt(II) porphyrin is an excellent photosensitizer for the production of singlet oxygen and will have potential applications in the field of photodynamic therapy as well as oxygen sensors