Propuesta de una metodología estándar para la caracterización de la organogelificación de aceites comestibles con ceras

Saturated and trans fatty acids play a significant role in the plastic properties of food. However, health recommendations suggest limiting their intake. One approach which got the attention of researchers was to decrease the amount of saturated and trans fatty acids in food by the structuring of edible oils through the crystallization of waxes. The underlying mechanisms that lead to organogelation and the properties that characterize well-structured edible oil have been slow to fully understand due in part to a lack of standardiza­tion in their analysis which often makes the comparison between research results from different laboratories difficult. The aim of this work was to review previously reported methods for the characterization of organo­gelation using vegetable and animal waxes, and to propose a minimal standardization for an organogelation analysis.Los ácidos grasos saturados y trans juegan un rol significativo en las propiedades plásticas de los alimentos. Sin embargo, las recomendaciones de salud sugieren limitar su consumo. Un enfoque que han propuesto investigadores científicos es la disminución en la cantidad de grasas trans y saturadas en la alimenta­ción por medio de la estructuración de aceites comestibles a partir de la cristalización de ceras. Los mecanismos por los cuales la organogelificación ocurre, así como las propiedades que caracterizan una buena estructuración del aceite, han sido descubiertos lentamente debido en parte a la falta de estandarización de los análisis impli­cados, lo que frecuentemente vuelve difícil la comparación entre resultados de investigación de distintos labo­ratorios. El objetivo de este trabajo es realizar una revisión de los principales métodos para la caracterización de la organogelificación y de los organogeles formados usando ceras vegetales y animales, proponiendo una estandarización mínima del análisis de organogelificación

Proximity DC squids in the long junction limit

We report the design and measurement of Superconducting/normal/superconducting (SNS) proximity DC squids in the long junction limit, i.e. superconducting loops interrupted by two normal metal wires roughly a micrometer long. Thanks to the clean interface between the metals, at low temperature a large supercurrent flows through the device. The dc squid-like geometry leads to an almost complete periodic modulation of the critical current through the device by a magnetic flux, with a flux periodicity of a flux quantum h/2e through the SNS loop. In addition, we examine the entire field dependence, notably the low and high field dependence of the maximum switching current. In contrast with the well-known Fraunhoffer-type oscillations typical of short wide junctions, we find a monotonous gaussian extinction of the critical current at high field. As shown in [15], this monotonous dependence is typical of long and narrow diffusive junctions. We also find in some cases a puzzling reentrance at low field. In contrast, the temperature dependence of the critical current is well described by the proximity effect theory, as found by Dubos {\it et al.} [16] on SNS wires in the long junction limit. The switching current distributions and hysteretic IV curves also suggest interesting dynamics of long SNS junctions with an important role played by the diffusion time across the junction.Comment: 12 pages, 16 figure

Direct measurement of the phase coherence length in a GaAs/GaAlAs square network

The low temperature magnetoconductance of a large array of quantum coherentloops exhibits Altshuler-Aronov-Spivak oscillations which periodicitycorresponds to 1/2 flux quantum per loop.We show that the measurement of the harmonics content in a square networkprovides an accurate way to determine the electron phase coherence length$L\_{\phi}$ in units of the lattice length without any adjustableparameters.We use this method to determine $L\_{\phi}$ in a network realised from a 2Delectron gas (2DEG) in a GaAS/GaAlAs heterojunction. The temperaturedependence follows a power law $T^{-1/3}$ from 1.3 K to 25 mK with nosaturation, as expected for 1D diffusive electronic motion andelectron-electron scattering as the main decoherence mechanism.Comment: Additional experimental data in version

Role of Spinophilin in Group I Metabotropic Glutamate Receptor Endocytosis, Signaling, and Synaptic Plasticity

Activation of Group I metabotropic glutamate receptors (mGluRs) activates signaling cascades, resulting in calcium release from intracellular stores, ERK1/2 activation, and long term changes in synaptic activity that are implicated in learning, memory, and neurodegenerative diseases. As such, elucidating the molecular mechanisms underlying Group I mGluR signaling is important for understanding physiological responses initiated by the activation of these receptors. In the current study, we identify the multifunctional scaffolding protein spinophilin as a novel Group I mGluR-interacting protein. We demonstrate that spinophilin interacts with the C-terminal tail and second intracellular loop of Group I mGluRs. Furthermore, we show that interaction of spinophilin with Group I mGluRs attenuates receptor endocytosis and phosphorylation of ERK1/2, an effect that is dependent upon the interaction of spinophilin with the C-terminal PDZ binding motif encoded by Group I mGluRs. Spinophilin knock-out results in enhanced mGluR5 endocytosis as well as increased ERK1/2, AKT, and Ca2+ signaling in primary cortical neurons. In addition, the loss of spinophilin expression results in impaired mGluR5-stimulated LTD. Our results indicate that spinophilin plays an important role in regulating the activity of Group I mGluRs as well as their influence on synaptic activity

The Use of Basal Area Increment to Preserve the Multi-Decadal Climatic Signal in Shrub Growth Ring Chronologies: A Case Study of Betula glandulosa in a Rapidly Warming Environment

Climate warming at high latitudes has contributed to the growing interest in shrub tree-ring analysis. Shrub architecture presents new challenges for dendrochronology, such as the seemingly lower and inconsistent climatic sensitivity of stems vs. root collars. Shrub stems may thus be considered as sub-optimal to study climate–growth relationships. In this paper, we propose that the lower climatic sensitivity of stems could be caused by the use of unsuitable detrending methods for chronologies spanning decades rather than centuries. We hypothesize that the conversion of the ring width (RW) to basal area increment (BAI) is better suited than traditional detrending methods to removing age/size-related trends without removing multi-decadal climate signals. Using stem and root collar samples collected from three sites in the forest–tundra ecotone of eastern Canada, we compared the climate–growth relationships of these two approaches for stems and root collars using mixed-effects models. The climate sensitivity was, on average, 4.9 and 2.7 times higher with BAI than with detrended (mean-centered) RW chronologies for stems and root collars, respectively. The climatic drivers of radial growth were identical for stems and root collars when using BAI (July temperature and March precipitation), but were inconsistent when using detrended RW series (root collars: July temperature and March precipitation at all sites; stems: April and June temperature, depending on the site). Although the use of BAI showed promising results for studying long-term climate signals in shrub growth chronologies, further studies focusing on different species and locations are needed before the use of BAI can become broadly used in shrub dendrochronology

Prion Protein Polymorphisms Affect Chronic Wasting Disease Progression

Analysis of the PRNP gene in cervids naturally infected with chronic wasting disease (CWD) suggested that PRNP polymorphisms affect the susceptibility of deer to infection. To test this effect, we orally inoculated 12 white-tailed deer with CWD agent. Three different PRNP alleles, wild-type (wt; glutamine at amino acid 95 and glycine at 96), Q95H (glutamine to histidine at amino acid position 95) and G96S (glycine to serine at position 96) were represented in the study cohort with 5 wt/wt, 3 wt/G96S, and 1 each wt/Q95H and Q95H/G96S. Two animals were lost to follow-up due to intercurrent disease. The inoculum was prepared from Wisconsin hunter-harvested homozygous wt/wt animals. All infected deer presented with clinical signs of CWD; the orally infected wt/wt had an average survival period of 693 days post inoculation (dpi) and G96S/wt deer had an average survival period of 956 dpi. The Q95H/wt and Q95H/G96S deer succumbed to CWD at 1,508 and 1,596 dpi respectively. These data show that polymorphisms in the PRNP gene affect CWD incubation period. Deer heterozygous for the PRNP alleles had extended incubation periods with the Q95H allele having the greatest effect

Presence and Seeding Activity of Pathological Prion Protein (PrPTSE) in Skeletal Muscles of White-Tailed Deer Infected with Chronic Wasting Disease

Chronic wasting disease (CWD) is a contagious, rapidly spreading transmissible spongiform encephalopathy (TSE), or prion disease, occurring in cervids such as white tailed-deer (WTD), mule deer or elk in North America. Despite efficient horizontal transmission of CWD among cervids natural transmission of the disease to other species has not yet been observed. Here, we report for the first time a direct biochemical demonstration of pathological prion protein PrPTSE and of PrPTSE-associated seeding activity, the static and dynamic biochemical markers for biological prion infectivity, respectively, in skeletal muscles of CWD-infected cervids, i. e. WTD for which no clinical signs of CWD had been recognized. The presence of PrPTSE was detected by Western- and postfixed frozen tissue blotting, while the seeding activity of PrPTSE was revealed by protein misfolding cyclic amplification (PMCA). Semi-quantitative Western blotting indicated that the concentration of PrPTSE in skeletal muscles of CWD-infected WTD was approximately 2000-10000 -fold lower than in brain tissue. Tissue-blot-analyses revealed that PrPTSE was located in muscle-associated nerve fascicles but not, in detectable amounts, in myocytes. The presence and seeding activity of PrPTSE in skeletal muscle from CWD-infected cervids suggests prevention of such tissue in the human diet as a precautionary measure for food safety, pending on further clarification of whether CWD may be transmissible to humans

How to measure, report and verify soil carbon change to realize the potential of soil carbon sequestration for atmospheric greenhouse gas removal

Global Change Biology published by John Wiley & Sons Ltd There is growing international interest in better managing soils to increase soil organic carbon (SOC) content to contribute to climate change mitigation, to enhance resilience to climate change and to underpin food security, through initiatives such as international ‘4p1000’ initiative and the FAO\u27s Global assessment of SOC sequestration potential (GSOCseq) programme. Since SOC content of soils cannot be easily measured, a key barrier to implementing programmes to increase SOC at large scale, is the need for credible and reliable measurement/monitoring, reporting and verification (MRV) platforms, both for national reporting and for emissions trading. Without such platforms, investments could be considered risky. In this paper, we review methods and challenges of measuring SOC change directly in soils, before examining some recent novel developments that show promise for quantifying SOC. We describe how repeat soil surveys are used to estimate changes in SOC over time, and how long-term experiments and space-for-time substitution sites can serve as sources of knowledge and can be used to test models, and as potential benchmark sites in global frameworks to estimate SOC change. We briefly consider models that can be used to simulate and project change in SOC and examine the MRV platforms for SOC change already in use in various countries/regions. In the final section, we bring together the various components described in this review, to describe a new vision for a global framework for MRV of SOC change, to support national and international initiatives seeking to effect change in the way we manage our soils