1/f Noise in Electron Glasses

We show that 1/f noise is produced in a 3D electron glass by charge fluctuations due to electrons hopping between isolated sites and a percolating network at low temperatures. The low frequency noise spectrum goes as \omega^{-\alpha} with \alpha slightly larger than 1. This result together with the temperature dependence of \alpha and the noise amplitude are in good agreement with the recent experiments. These results hold true both with a flat, noninteracting density of states and with a density of states that includes Coulomb interactions. In the latter case, the density of states has a Coulomb gap that fills in with increasing temperature. For a large Coulomb gap width, this density of states gives a dc conductivity with a hopping exponent of approximately 0.75 which has been observed in recent experiments. For a small Coulomb gap width, the hopping exponent approximately 0.5.Comment: 8 pages, Latex, 6 encapsulated postscript figures, to be published in Phys. Rev.

Protective effects of phenolic constituents from Cytisus multiflorus, Lamium album L. and Thymus citriodorus on liver cells

The present study investigated the antioxidant and cytoprotective effects of purified ethanolic extracts of Cytisus multiflorus, Lamium album L. and Thymus citriodorus plants. These extracts showed high antioxidant activity in DPPH and reducing power assays. Using a model of chemical stress induced by potassium dichromate (DK) in human hepatoblastoma HepG2 cells, 50 ug/mL of C. multiflorus, L. album and T. citriodorus extracts decreased the rate of reactive oxygen species (ROS) production by 35%, 26% and 20%, respectively, when exposed to 25 mu M of DK. This effect was also observed for the treatment of cells with individual polyphenolic compounds determined in the extracts, or with mixtures prepared with individual polyphenolic compounds simulating the phenolic composition of the extracts. Additionally, the purified ethanolic extracts and the prepared polyphenolic mixtures showed a cytoprotective effect against DK-induced toxicity. The overall results emphasize the contribution of polyphenols in antioxidant and cytoprotective properties of the studied plants

Effects of minor compounds from virgin olive oil on inflammatory response in human leukocytes

Mediterranean diet protects against cardiovascular diseases such as atherosclerosis, now considered an inflammatory disorder. Virgin olive oil is one of the most important foods in this diet, leading to the suggestion that health benefits of Mediterranean diet are achieved at least partially due to the consumption of virgin olive oil. Extra virgin olive oil (EVOO) is the highest quality oil based on its chemical and sensorial properties. Our aim was to evaluate the anti-inflammatory effects of minor compounds found in the unsaponifibale fraction of EVOO on activated human monocytes and neutrophils. For this purpose, we isolated monocytes and neutrophils from blood samples of healthy volunteers. We also isolated the unsaponifiable fraction (UF) from EVOO. Cells were incubated with UF at different concentrations and the pro-inflammatory stimulus LPS. Afterwards, RNA was obtained from cells and then converted into cDNA. The relative gene expression of pro-inflammatory and anti-inflammatory markers was assessed by qRT-PCR. We found that UF from EVOO reduced relative gene expression of pro-inflammatory markers in a dose-dependent manner both in human monocytes and neutrophils. In contrast, UF from EVOO increased relative gene expression of anti-inflammatory markers in these cells. These findings unveil a role of UF from EVOO in the benefits from consumption of EVOO in disorders related to inflammation

Wind Resource Assessment on Puna Island

Puna Island, located in the Pacific Ocean off the southern coast of Ecuador, has a population of approximately 3344 inhabitants. However, not all inhabitants have access to electricity, which is largely supplied by diesel generators. Therefore, to identify a renewable, sustainable, environmentally friendly and low-cost alternative, a 40-m-high anemometer tower was installed for wind resource assessment and to determine the possibility of generating electricity from wind energy. Based on mathematical models for electricity generation from wind energy, data were analyzed using the software Windographer and WAsP, to determine a long-term wind speed of 4.8 m/s and a mean wind power density of 272 W/m(2). By simulating the use of a 3.3-MW wind turbine, we demonstrated that as much as 800 kWh could be generated during the hours when the wind reaches its highest speed. In addition to demonstrating the technical feasibility of meeting the electricity demands of Puna Island through wind power, this study exemplifies a method that can be used for wind resource assessment in any location

Increase of the load carrying capacity of aluminium 2024-T3 by means of a NiP-CRC-DLC coating

The present investigation has been conducted in order to evaluate the tribological behavior of an AA2024-T3 aluminum alloy, coated with a NiP-CrC-DLC coating. The effect of NiP as intermediate layer was evaluated by carrying out calculations using ELASTICA © in order to determine its adequate thickness needed to avoid the plastic deformation of the substrate, ensuring then the integrity of the coating. To evaluate the efficiency of these calculations, a number of dry sliding wear tests were performed employing a ball-on-disk configuration, where alumina balls of 6 mm in diameter were used as counterpart. The sliding wear tests were carried out up to a sliding distance of 800 m, with a normal load of 5 N, a linear speed of 5 cm/s and a contact radius of 3 mm. The wear tracks were analyzed by means of scanning electron microscopy (SEM) techniques coupled with energy dispersive spectroscopy (EDS). The wear volume was determined by means of optical profilometry. The results indicate that, under the present testing conditions, the NiP-CrC-DLC coating exhibits a satisfactory behavior from the mechanical stability point of view when the thickness of the NiP layer is higher than 60 µm, since no surface failures were observed at the end of the tests. For the coated system, the magnitude of the friction coefficient was found to be of approximately 0.1 and that of the wear rate was of about 2.31 ± 0.09 x 10-16 m3/N.m. On the contrary, for the uncoated substrate, the friction coefficient was of approximately 0.5 and the wear rate of 5.46 x 10-13 m3/N.m, that is to say, 3 orders of magnitude greater than that determined for the coated system

Implementation of the Enhanced Recovery After Surgery (ERAS®) program in neurosurgery.

Over the past decade, Enhanced Recovery After Surgery (ERAS®) guidelines have been proven to simplify postoperative care and improve recovery in several surgical disciplines. The authors set out to create and launch an ERAS® program for cranial neurosurgery that meets official ERAS® Society standards. The authors summarize the successive steps taken to achieve this goal in two specific neurosurgical conditions and describe the challenges they faced. Pituitary neuroendocrine tumors (Pit-NET) resected by a transsphenoidal approach and craniosynostosis (Cs) repair were selected as appropriate targets for the implementation of ERAS® program in the Department of Neurosurgery. A multidisciplinary team with experience in managing these pathologies was created. A specialized ERAS® nurse coordinator was hired. An ERAS® certification process was performed involving 4 seminars separated by 3 active phases under the supervision of an ERAS® coach. The ERAS® Pit-NET team included 8 active members. The ERAS® Cs team included 12 active members. Through the ERAS® certification process, areas for improvement were identified, local protocols were written, and the ERAS® program was implemented. Patient-centered strategies were developed to increase compliance with the ERAS® protocols. A prospective database was designed for ongoing program evaluation. Certification was achieved in 18 months. Direct costs and time requirements are reported. Successful ERAS® certification requires a committed multidisciplinary team, an ERAS® coach, and a dedicated nurse coordinator

Em busca de antioxidantes e agentes hepatoprotetores em plantas

As plantas são usadas desde há séculos pelo Homem devido aos seus efeitos benéficos para a saúde, no entanto na maior parte dos casos, nem a composição química nem o mecanismo associado a cada efeito se encontram descritos. De entre as plantas mediterrânicas mais usadas, podem destacar-se espécies das famílias Lamiaceae e Fabaceae, que são reconhecidas fontes de compostos fenólicos. Dado o largo espetro de efeitos biológicos que são atribuídos a este tipo de compostos, vários estudos têm sido desenvolvidos com vista à sua aplicação na indústria farmacêutica, alimentar e cosmética. Esta apresentação focará alguns dos efeitos biológicos descritos na literatura para plantas das famílias Lamiaceae e Fabaceae, com especial ênfase nos géneros Cytisus, Lamium, Lavandula, Leonurus, Mentha e Thymus. Exemplos dos compostos naturais associados a esses benefícios serão igualmente indicados. Adicionalmente, serão apresentados resultados relativos ao efeito antioxidante e efeito hepatoprotetor de extractos etanólicos obtidos a partir de plantas de espécies dos géneros mencionados e que estão pouco exploradas até ao momento, nomeadamente a Cytisus multiflorus, Lamium album, Lavandula dentata, Leonurus cardiaca, Mentha aquatica e o Thymus citriodorus. Os resultados mostram que a maior parte dos extratos das plantas estudadas possuem uma elevada capacidade antioxidante, tal como demonstrado em modelos químicos e num modelo biológico. Alguns extratos, em particular os das plantas L. album e C. multiflorus, demonstraram ainda moderado poder hepatoprotetor. Para além disso, experiências efetuadas com compostos fenólicos puros permitem afirmar que estes efeitos estão intimamente relacionados com o seu conteúdo em compostos fenólicos. Os estudos até à data sugerem que estas plantas podem ter potencial para aplicação industrial. Estudos adicionais, incluindo modelos in vivo, são agora necessários para determinarem essa aplicação

Further Characterization of the Electrogenicity and pH Sensitivity of the Human Organic Anion-Transporting Polypeptides OATP1B1 and OATP1B3

Organic anion-transporting polypeptides (OATPs) are involved in the liver uptake of many endogenous and xenobiotic compounds, such as bile acids and drugs, respectively. Using Xenopus laevis oocytes and Chinese hamster ovary (CHO) cells expressing rat Oatp1a1, human OATP1B1, or OATP1B3, the sensitivity of these transporters to extracellular/intracellular pH (pHo/pHi) and changes in plasma membrane potential (ΔΨ) was investigated. In X. laevis oocytes, nonspecific plasma membrane permeability increased only at pHo below 4.5. Above this value, both using oocytes and CHO cells, extracellular acidification affected differently the specific transport of taurocholic acid (TCA) and estradiol 17β-d-glucuronide (E217βG) by Oatp1a1 (stimulation), OATP1B1 (inhibition), and OATP1B3 (stimulation). Changes in substrate uptake in the presence of valinomycin (K+-ionophore), carbonyl cyanide 3-chlorophenylhydrazone and nigericin (protonophores), and amiloride (Na+/H+-inhibitor) and cation replacement in the medium were studied with fluorescent probes for measuring substrate uptake (cholylglycyl amidofluorescein) and changes in pHi (SNARF-4F) and ΔΨ [DilC1(5)]. The results suggest that activity of these three carriers is sodium/potassium-independent and affected differently by changes in pHo and ΔΨ: Oatp1a1 was confirmed to be an electroneutral anion exchanger, whereas the function of both OATP1B1 and OATP1B3 was markedly affected by the magnitude of ΔΨ. Moreover, electrophysiological measurements revealed the existence of a net anion influx associated to OATP1B1/OATP1B3-mediated transport of TCA, E217βG, and estrone-3-sulfate. Furthermore, a leakage of Na+ through OATP1B1 and OATP1B3, which is not coupled to substrate transport, was found. In conclusion, these results suggest that OATP1B1 and OATP1B3 are electrogenic transporters whose activity may be strongly affected under circumstances of displacement of local pH