1,830 research outputs found
Effects of Market Reform on Access to Food by Low-Income Households: Evidence from Four Countries in Eastern and Southern Africa
Food Consumption/Nutrition/Food Safety, Downloads June 2008 - June 2009: 10,
Using zeta-potential measurements to quantify peptide partition to lipid membranes
© The Author(s) 2011. This article is published with open access at Springerlink.com.Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.Many cellular phenomena occur on the biomembranes. There are plenty of molecules (natural or xenobiotics) that interact directly or partially with the cell membrane. Biomolecules, such as several peptides (e.g., antimicrobial peptides) and proteins, exert their effects at the cell membrane level. This feature makes necessary investigating their interactions with lipids to clarify their mechanisms of action and side effects necessary. The determination of molecular lipid/water partition constants (Kp) is frequently used to quantify the extension of the interaction. The determination of this parameter has been achieved by using different methodologies, such as UV-Vis absorption spectrophotometry, fluorescence spectroscopy and ζ-potential measurements. In this work, we derived and tested a mathematical model to determine the Kp from ζ-potential data. The values obtained with this method were compared with those obtained by fluorescence spectroscopy, which is a regular technique used to quantify the interaction of intrinsically fluorescent peptides with selected biomembrane model systems. Two antimicrobial peptides (BP100 and pepR) were evaluated by this new method. The results obtained by this new methodology show that ζ-potential is a powerful technique to quantify peptide/lipid interactions of a wide variety of charged molecules, overcoming some of the limitations inherent to other techniques, such as the need for fluorescent labeling.This work was partially supported by project PTDC/QUI/ 69937/2006 from Fundação para a Ciência e Tecnologia-Ministério da Ciência, Tecnologia e Ensino Superior (FCT-MCTES, Portugal), and by Fundação Calouste Gulbenkian (Portugal). JMF and MMD also thank FCT-MCTES for grants IMM/BT/37-2010 and SFRH/BD/41750/2007, respectively
Partitioning and purification of polygalacturonases produced by Aspergillus niger URM 5162 using PEG-phosphate in an aqueous two-phase system
Pectinases, or pectinolytic enzymes, are naturally produced by plants, filamentous fungi, bacteria and yeasts. The pectinases are
of great importance to clarify and reduce viscosity in fruit juices, improving and increasing tbe filtration efficiency. When used
in the crushing of grapes or wine must improve juice extraction, reduce the time to clarify and enhance tbe content ofterpenes in
wine. The filamentous fungi most frequently used fur industrial purposes because as much as 90% ofthe enzyme can be excreted
into the culture medium. The partitioning and purification of polygalacturonases (PG) produced by Aspergillus niger URM
5162 were investigated in aqueous two-phase systems (ATPS), furmed by polyetbylene glycol and phosphate salts
(PE(ijlhosphate). To evaluate the effect oftbe 4 independent variables- molar mass ofpolyetbylene glycol (PEG) (400-8000
g1nol MPEG), PEG concentration (12.5-17.5%, w/w- CPEG), phosphate concentration (15-25%, ...W, CPHOS) and pH (6.0, 8.0)
- on the 3 response variables: partition coefficient (K), activity yield (Y) and purification fàctor (PF), a fuctorial design (24) was
used. The endo-polygalacturonases (endo-PG) were prefurentially partitioned in tbe top phase. For endo-PG, the highest values
for the response variables K, Y and PF of 1.23, 74.04% and 8.18, respectively, were obtained for a CPEG of 12.5% (...W), MPEG
of8000 g1nol, and CPHOS of25% (w/w) at pH 6.0. Also, exo-polygalacturonases (exo-PG) were preferentially partitioned in the
top phase. ln tbis case, the highest values ofK (2.40), Y (33.33%), and PF (1.98) were obtained with a MPEG of 8000 g1nol,
CPEG of 12.5% (...W), and CPHOS of25% (...W) at pH 6.0. ln both cases, MPEG had a positive influence on K, Y and PF. The
conditions ofMPEG 8000 g1nol, CPEG of 12.5% (...W), and CPHOS of25% (...W) at pH 6.0 were considered the most suitable
for tbe purification of PG produced by A. niger URM 5162. Furtbermore, MPEG and CPHOS were the most important
independent variables. The PEG/phosphate system is a useful cost-effective altemative for PG purification
‘Trial and error…’, ‘…happy patients’ and ‘…an old toy in the cupboard’: a qualitative investigation of factors that influence practitioners in their prescription of foot orthoses
Background: Foot orthoses are used to manage of a plethora of lower limb conditions. However, whilst the theoretical
foundations might be relatively consistent, actual practices and therefore the experience of patients is likely to be less so.
The factors that affect the prescription decisions that practitioners make about individual patients is unknown and hence
the way in which clinical experience interacts with knowledge from training is not understood. Further, other influences
on orthotic practice may include the adoption (or not) of technology. Hence the aim of this study was to explore, for
the first time, the influences on orthotic practice.
Methods: A qualitative approach was adopted utilising two focus groups (16 consenting participants in total; 15
podiatrists and 1 orthotist) in order to collect the data. An opening question “What factors influence your orthotic
practice?” was followed with trigger questions, which were used to maintain focus. The dialogue was recorded
digitally, transcribed verbatim and a thematic framework was used to analyse the data.
Results: There were five themes: (i) influences on current practice, (ii) components of current practice, (iii) barriers
to technology being used in clinical practice, (iv) how technology could enhance foot orthoses prescription and
measurement of outcomes, and (v) how technology could provide information for practitioners and patients. A final
global theme was agreed by the researchers and the participants: ‘Current orthotic practice is variable and does not
embrace technology as it is perceived as being not fit for purpose in the clinical environment. However, practitioners
do have a desire for technology that is usable and enhances patient focussed assessment, the interventions, the clinical
outcomes and the patient’s engagement throughout these processes’.
Conclusions: In relation to prescribing foot orthoses, practice varies considerably due to multiple influences.
Measurement of outcomes from orthotic practice is a priority but there are no current norms for achieving this.
There have been attempts by practitioners to integrate technology into their practice, but with largely negative
experiences. The process of technology development needs to improve and have a more practice, rather than
technology focus
Spontaneous Interlayer Coherence in Double-Layer Quantum Hall Systems: Symmetry Breaking Interactions, In-Plane Fields and Phase Solitons
At strong magnetic fields double-layer two-dimensional-electron-gas systems
can form an unusual broken symmetry state with spontaneous inter-layer phase
coherence. The system can be mapped to an equivalent system of pseudospin
particles with pseudospin-dependent interactions and easy-plane magnetic order.
In this paper we discuss how the presence of a weak interlayer tunneling term
alters the properties of double-layer systems when the broken symmetry is
present. We use the energy functional and equations of motion derived earlier
to evaluate the zero-temperature response functions of the double-layer system
and use our results to discuss analogies between this system and
Josephson-coupled superconducting films. We also present a qualitative picture
of the low-energy charged excitations of this system. We show that parallel
fields induce a highly collective phase transition to an incommensurate state
with broken translational symmetry.Comment: 26 pages, RevTex, 8 postscript figures (submitted to Phys. Rev. B
Public awareness and engagement in relation to the coastal oil spill in northeast Brazil
Social media data is a rich source of information to assess human activities in catastrophic events. Here, we use social media data to understand how the 2019 Brazilian oil spill influenced social attitudes. Data were collected from the globally popular Instagram platform between August 1, 2019 and March 1, 2020. First, we manually identified the 5 most popular (portuguese language) hashtags related to the oil spill #oleonononordeste;#desastreambiental;#ma rsemoleo;#sosnordeste;#ma rsempetroleo. In the sequence, we collected information on captions, post metadata and users associated with posts retrieved using the selected hashtags. We identified a total of 7,413 posts. These posts were grouped in topics: government (47.76%), protest (24.37%), volunteers (24.45%), biodiversity (0.003%), origin (0.006%), tourism (0.008%) and others (0.016%). All topics had the peak of posts in October and November 2019. Nevertheless, interest in the oil spill was temporary, with most posts appearing in the 2-4 months after the beginning of the disaster. Our findings illustrate the enormous potential of using social media data for understanding and monitoring human engagement with environmental disasters, but also suggest that conservationists and environmental groups may only have a limited 'window of opportunity' to engage and mobilize public support for remediation and restoration efforts.Peer reviewe
MicroRNA Hsa-miR-134 is a circulating biomarker for mesial temporal lobe epilepsy
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Epilepsy is misdiagnosed in up to 25% of patients, leading to serious and long-lasting consequences. Recently, circulating microRNAs have emerged as potential biomarkers in a number of clinical scenarios. The purpose of this study was to identify and to validate circulating microRNAs that could be used as biomarkers in the diagnosis of epilepsy. Quantitative real-time PCR was used to measure plasma levels of three candidate microRNAs in two phases of study: an initial discovery phase with 14 patients with mesial temporal lobe epilepsy (MTLE), 13 with focal cortical dysplasia (FCD) and 16 controls; and a validation cohort constituted of an independent cohort of 65 patients with MTLE and 83 controls. We found hsa-miR-134 downregulated in patients with MTLE (p = 0.018) but not in patients with FCD, when compared to controls. Furthermore, hsa-miR-134 expression could be used to discriminate MTLE patients with an area under the curve (AUC) of 0.75. To further assess the robustness of hsa-miR-134 as a biomarker for MTLE, we studied an independent cohort of 65 patients with MTLE, 27 of whom MTLE patients were responsive to pharmacotherapy, and 38 patients were pharmacoresistant and 83 controls. We confirmed that hsa-miR-134 was significantly downregulated in the plasma of patients with MTLE when compared with controls (p < 0.001). In addition, hsa-miR-134 identified patients with MTLE regardless of their response to pharmacotherapy or the presence of MRI signs of hippocampal sclerosis. We revealed that decreased expression of hsa-miR-134 could be a potential non-invasive biomarker to support the diagnosis of patients with MTLE.Epilepsy is misdiagnosed in up to 25% of patients, leading to serious and long-lasting consequences. Recently, circulating microRNAs have emerged as potential biomarkers in a number of clinical scenarios. The purpose of this study was to identify and to v124FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)2013/07559-3; 2013/00099-7sem informaçãosem informaçã
Distribution and Abundance of Fin whales and other baleen whales in the European Atlantic
The abundance of fin whales (Balaenoptera physalus) and other baleen whales was generated from data collected during
shipboard sightings surveys as part of the Cetacean Offshore Distribution and Abundance in the European Atlantic project
(CODA). The survey area covered offshore waters beyond the continental shelf of the UK, Ireland, France and Spain. The area
was stratified into four blocks and was surveyed by five ships during July 2007. Double platform methods employing the trialconfiguration
method (BT-method) were used. Fin, sei (B. borealis) and minke whales (B. acutorostrata) were positively
identified, with possible sightings of blue whales (B. musculus). Abundance was estimated for these species and for “large baleen
whales” which included fin, sei, fin/sei and blue whales. Abundance for the larger species was estimated using the Mark-
Recapture Line Transect design-based method and also model-based methods using density surface modelling. Sample size
limitations dictated that conventional line transect sampling methods were used to estimate the abundance of minke whales.
Estimates from the two methods were comparable but model-based methods improved the precision and were considered best
estimates. The density of large baleen whale species was greatest in the southern end of the survey area and water depth,
temperature and distance to the 2000m contour were important predictors of their distribution. The total abundance estimated for
the entire survey area was 9,019 (CV=0.11) fin whales and 9,619 (CV= 0.11) large baleen whales. The uncertainty around these
estimates due to duplicate classification and species identification were explored. The fin whale estimate is likely to be
underestimated because it excludes unidentified large whales, of which a large proportion was likely to have been fin whales.
Notwithstanding this, these large baleen whale abundance estimates are the first robust estimates (corrected for responsive
movement and g(0)) for this area. The estimated abundance of minke whales was 6,765 (CV=0.99) and sightings were restricted
to the northern blocks of the survey area. The minke whale estimate, although imprecise and likely underestimated, does provide a
baseline figure for this area and, when considered with results from the SCANS-II continental shelf surveys of July 2005, gives a
more comprehensive picture of this species in the European Atlantic. These abundance estimates are important contributions to
the conservation and management of these species in the Northeast Atlantic
Activation of Type 1 Cannabinoid Receptor (CB1R) promotes neurogenesis in murine subventricular zone cell cultures
The endocannabinoid system has been implicated in the modulation of adult neurogenesis. Here, we describe the effect of type 1 cannabinoid receptor (CB1R) activation on self-renewal, proliferation and neuronal differentiation in mouse neonatal subventricular zone (SVZ) stem/progenitor cell cultures. Expression of CB1R was detected in SVZ-derived immature cells (Nestin-positive), neurons and astrocytes. Stimulation of the CB1R by (R)-(+)-Methanandamide (R-m-AEA) increased self-renewal of SVZ cells, as assessed by counting the number of secondary neurospheres and the number of Sox2+/+ cell pairs, an effect blocked by Notch pathway inhibition. Moreover, R-m-AEA treatment for 48 h, increased proliferation as assessed by BrdU incorporation assay, an effect mediated by activation of MAPK-ERK and AKT pathways. Surprisingly, stimulation of CB1R by R-m-AEA also promoted neuronal differentiation (without affecting glial differentiation), at 7 days, as shown by counting the number of NeuN-positive neurons in the cultures. Moreover, by monitoring intracellular calcium concentrations ([Ca2+](i)) in single cells following KCl and histamine stimuli, a method that allows the functional evaluation of neuronal differentiation, we observed an increase in neuronal-like cells. This proneurogenic effect was blocked when SVZ cells were co-incubated with R-m-AEA and the CB1R antagonist AM 251, for 7 days, thus indicating that this effect involves CB1R activation. In accordance with an effect on neuronal differentiation and maturation, R-m-AEA also increased neurite growth, as evaluated by quantifying and measuring the number of MAP2-positive processes. Taken together, these results demonstrate that CB1R activation induces proliferation, self-renewal and neuronal differentiation from mouse neonatal SVZ cell cultures.Fundacao para a Ciencia e a Tecnologia - Portugal [POCTI/SAU-NEU/68465/2006, PTDC/SAU-NEU/104415/2008, PTDC/SAU-NEU/101783/2008, POCTI/SAU-NEU/110838/2009]; Fundacao Calouste Gulbenkian [96542]; Fundacao para a Ciencia e Tecnologiainfo:eu-repo/semantics/publishedVersio
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