Thin-layer chromatographic collector-eluter.

A combination thin-layer chromatographic collector and elution apparatus is described. The device is designed to minimize manipulations and maximize accuracy and can be used for both analytical and small-scale preparative separations.     

Voltage-dependent conductance induced by hemocyanin in black lipid films

When hemocyanin is added to a black lipid film, the conductance increases in discrete steps. For negative potentials the single step conductance is constant, but for positive potentials the step conductance appears to decrease as the potential increases. At high positive potentials the conductance fluctuates between several levels. These data suggest that, in lipid membranes, hemocyanin conducts ions through discrete channels. The voltage-dependent conductance observed at high levels of conductance seems to be a consequence of the properties of the conductance of the single channel.     

The nature of the voltage-dependent conductance of the hemocyanin channel.

The electrical responses of individual hemocyanain channels in oxidized cholesterol membranes demonstrate that the voltage-dependent conductance of many-chanel membranes arises from two different mechanisms. These are the voltage-dependent redistribution of channels among several discrete single-channel conductance states themselves. The relaxation time for the discrete conductance changes is of the order of seconds nd the relaxation time of the continuous conductance changes is of the order 10(-4) seconds. As salt concentration in the bathing medium is increased, the single-channel conductance first increases lineary and then saturates. The characteristics of the saturation curves suggest that the continuous conductance changes occur at the edges of the channel and that the mean time an ion spends in the channel is 4 nanoseconds...     

Distribution of interstitial retinol-binding protein (IRBP) in the vertebrates

Immunoblots of interphotoreceptor matrix preparations from 20 species belonging to six vertebrate classes were probed with antibodies against bovine interstitial retinol-binding protein (b-IRBP). Each preparation displayed an immunoreactive protein band. In the Osteichthyes, the apparent Mr of this band was 67,600 +/- 2,700 (mean +/- SD, n = 8). In two of the Osteichthyes, the band was resolved into a closely spaced doublet. Including previously published data for five mammals and one amphibian, species from the other classes (Chondrichthyes, one species; Amphibia, four species; Reptilia, one species; Aves, one species; Mammalia, nine species) had IRBPs with Mr that averaged 2.0 times that of the Osteichthyes, namely 134,200 +/- 8,600 (mean +/- SD, n = 17). Frog IRBP was very similar to mammalian IRBP in terms of its immunohistochemical distribution (determined with rabbit anti-frog IRBP antibodies), its molecular weight (sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel-filtration chromatography), retinol- and concanavalin A-binding ability, and because it was synthesized and secreted in vitro by the isolated retina but not by the pigmented layers of eye. Goldfish IRBP apparently binds exogenous (3H)-retinol but does not bind concanavalin A and has about half the Mr of frog IRBP. The occurrence of IRBP-like proteins cross-reacting with anti b-IRBP antibodies in the interphotoreceptor matrix of all six major vertebrate classes is consistent with the hypothesis that IRBP is an important element in the vertebrate visual cycle.     

Nasal Priming with Lactobacillus rhamnosus CRL1505 Stimulates Mononuclear Phagocytes of Immunocompromised Malnourished Mice: Improvement of Respiratory Immune Response

The effect of Lactobacillus rhamnosus CRL1505 (Lr) on macrophages (Ma) and dendritic cells (DC) in the orchestration of anti-pneumococcal immunity was stud     

A standardized assessment of forest mammal communities reveals consistent functional composition and vulnerability across the tropics

The understanding of global diversity patterns has benefitted from a focus on functional traits and how they relate to variation in environmental conditions among assemblages. Distant communities in similar environments often share characteristics, and for tropical forest mammals, this functional trait convergence has been demonstrated at coarse scales (110–200 km resolution), but less is known about how these patterns manifest at fine scales, where local processes (e.g. habitat features and anthropogenic activities) and biotic interactions occur. Here, we used standardized camera trapping data and a novel analytical method that accounts for imperfect detection to assess how the functional composition of terrestrial mammal communities for two traits – trophic guild and body mass – varies across 16 protected areas in tropical forests and three continents, in relation to the extent of protected habitat and anthropogenic pressures. We found that despite their taxonomic differences, communities generally have a consistent trophic guild composition, and respond similarly to these factors. Insectivores were found to be sensitive to the size of protected habitat and surrounding human population density. Body mass distribution varied little among communities both in terms of central tendency and spread, and interestingly, community average body mass declined with proximity to human settlements. Results indicate predicted trait convergence among assemblages at the coarse scale reflects consistent functional composition among communities at the local scale, suggesting that broadly similar habitats and selective pressures shaped communities with similar trophic strategies and responses to drivers of change. These similarities provide a foundation for assessing assemblages under anthropogenic threats and sharing conservation measures.     

A social panorama within the life cycle thinking and the circular economy: a literature review

Purpose

This literature review aims to present the current methodologies that have been developed to perform a social life cycle assessment (sLCA) and to display the main differences among them. In addition to that, to identify the nexus between sLCA and circular economy (CE) and to what extent this life cycle technique has been involved within CE studies.

Methods

An analysis of scientific literature using online databases was made. A total of 76 publications, including all industry sectors worldwide, were chosen spanning 11 years, from 2009 to 2020. Special attention was made to the methodology used to assess the social impacts, the impact categories analyzed, and whether there is or not a circular economy case. All the impact categories of both UNEP/SETAC and PSIA were taken into account when doing the review, and the top three of the categories are mentioned here.

Results and discussion

The leadership of the UNEP/SETAC methodology is clear with 58 cases. Almost 90% of the case studies are focused on products while the remaining ones are related with services. Workers are the most considered stakeholder when conducting an sLCA research, followed by local communities and society. Regarding the impact assessment, the performance reference point (PRP) was the most common method used. When considering the CE even when some cases included the end-of-life stage in the system boundaries, the studies did not consider the actors from that stage; excluding these cases, one out of four articles has a link with CE, a promising proportion taking into account the early stage of both concepts (i.e., sLCA and CE).

Conclusions

UNEP/SETAC guidelines seem to be the most promising methodology due to its reception among the scientific community. However, a more industry-oriented approach is proposed by the Roundtable for Product Social Metrics (PSIA) in a way to respond to manufacturing companies’ demand. Regardless of the type of methodology to be implemented, workers represent the key stakeholder when assessing social impacts. The change in usual patterns is leading to a change in the way how stakeholders interact and therefore new and more impacts may arise, and that is the reason why it is important to include the CE into the sLCA. A series of challenges such as the feasibility of aggregating all the life cycle techniques to one (life cycle sustainability assessment), data availability, and quality are still present for the moment.