An electrochemical rebalance cell for Redox systems

An electrochemical rebalance cell for maintaining electrochemical balance, at the system level, of the acidified aqueous iron chloride and chromium chloride reactant solutions in the redox energy storage system was constructed and evaluated. The electrochemical reaction for the cathode is Fe(+3) + e(-) yields Fe(+2), and that for the anode is 1/2H2 yields H(+) + e(-). The iron (carbon felt) electrode and the hydrogen (platinized carbon) electrode are separated by an anion exchange membrane. The performance of the rebalance cell is discussed as well as the assembly of a single rebalance cell and multicell stacks. Various cell configurations were tested and the results are presented and discussed. The rebalance cell was also used to demonstrate its ability, as a preparative tool, for making high purity solutions of soluble reduced metal ionic species. Preparations of titanium, copper, vanadium and chromium ions in acidified solutions were evaluated

Effects of Liposomes Contained in Thermosensitive Hydrogels as Biomaterials Useful in Neural Tissue Engineering

Indexación: Scopus.Advances in the generation of suitable thermosensitive hydrogels for the delivery of cells in neural tissue engineering demonstrate a delicate relationship between physical properties and capabilities to promote cell proliferation and differentiation. To improve the properties of these materials, it is possible to add liposomes for the controlled release of bioactive elements, which in turn can affect the physical and biological properties of the hydrogels. In the present investigation, different hydrogels based on Pluronic F127 have been formulated with the incorporation of chitosan and two types of liposomes of two different sizes. The rheological and thermal properties and their relation with the neurite proliferation and growth of the PC12 cell line were evaluated. Our results show that the incorporation of liposomes modifies the properties of the hydrogels dependent on the concentration of chitosan and the lipid type in the liposomes, which directly affect the capabilities of the hydrogels to promote the viability and differentiation of PC12 cells. © 2017 by the authors.http://www.mdpi.com/1996-1944/10/10/112

The effect of spatial, spectral and radiometric factors on classification accuracy using thematic mapper data

An experiment of a factorial design was conducted to test the effects on classification accuracy of land cover types due to the improved spatial, spectral and radiometric characteristics of the Thematic Mapper (TM) in comparison to the Multispectral Scanner (MSS). High altitude aircraft scanner data from the Airborne Thematic Mapper instrument was acquired over central California in August, 1983 and used to simulate Thematic Mapper data as well as all combinations of the three characteristics for eight data sets in all. Results for the training sites (field center pixels) showed better classification accuracies for MSS spatial resolution, TM spectral bands and TM radiometry in order of importance

Social Presence in Online Discussion Forums

El uso de foros de discusión en línea como una herramienta para el aprendizaje colaborativo requiere que los estudiantes se perciban mutuamente como personas reales y generen lazos afectivos entre ellos. Se investigó la relación entre la presencia social de los participantes en un foro y sus posiciones en las redes sociales de amistad, consejo, y adversarios formadas con compañeros. Se encontró una correlación negativa entre la centralidad de los participantes en la red de adversarios con el uso de indicadores afectivos, más no con indicadores cohesivos ni interactivos. No se encontraron correlaciones significativas entre la centralidad en las redes de consejo y amistad con ninguno de los tipos de indicadores de presencia social.When using online discussion boards as a tool for collaborative learning, students should be able to perceive each other as real people and create affective bonds between them. This paper assesses the relationship between social presence indicators and participants' messages to an online discussion board and his or her centrality in the advice, friendship, and hindrance social network created by all participants. A negative correlation was found between the use of affective indicators and centrality in the hindrance networks; no significant correlations were found between the centrality in the other networks and any kind of indicator of social presence

A cross-cultural study of leisure among Mexicans in the state of Guerrero, Mexico and Mexican immigrants from Guerrero in the United States

The goal of this study was to (a) Examine the existence and the understanding of the concept of leisure among Mexicans from the state of Guerrero, Mexico and among Mexican immigrants from Guerrero, residing in Chicago, IL with specific emphasis on age, gender, and marital status; (b) Identify forces that shape the experience of leisure among Mexicans from the state of Guerrero and among Mexican immigrants from the state of Guerrero, residing in Chicago, IL; and (c) Identify changes in the understanding of the concept and the meaning of leisure, and in leisure behavior among Mexicans from Guerrero caused by immigration to the United States. In order to collect data for this study, 14 interviews with adult residents of Chilpancingo, Guerrero, Mexico and 10 interviews with adult first generation immigrants from Guerrero to Chicago, Illinois were conducted in 2008 and 2009. The findings of the study revealed that the understanding and the meaning of leisure, tiempo libre, among this population was largely similar to the Western notion of leisure, as it was considered to be a subset of time, free from obligations and compulsory activities. Leisure was also considered a state of being where the individual is free to participate in the activity, desires to participate in the activity, and strives to obtain positive outcomes from participation. The way the immigrants from Guerrero defined and understood leisure did not seem to change with immigration. The important role that family played in the lives of both people in Guerrero and Mexican immigrants in the U.S. had a major impact on their leisure activities. Leisure was planned mostly around the family and each member of the family had a pre-established role depending on his or her age and gender. Some of the activities done in the company of family members included family gatherings where the adults could talk with each other and where the children could interact during an unstructured play. In both locations family factors, economic conditions, social influences, religion, and safety were the major forces that shaped leisure behavior of the participants. The main differences between interviewees residing in Guerrero, Mexico and in Chicago, IL were related to the feeling of having more freedom and choices with regards to leisure activities and increased participation in structured leisure activities after immigration. On the other hand, long work hours, physically strenuous employment, and lack of knowledge of the available leisure options constrained leisure of Mexican immigrants in Chicago. Participants believed that although their incomes in the U.S. were higher than in Mexico, leisure activities were more expensive in the U.S. and, thus, money was a major constraint on leisure. Picnicking and family gatherings were among the most popular activities in both Mexico and the United States, yet they took a new dimension after immigration. Because many immigrants had come to the United States by themselves or with few friends or family members, leisure occasions were used to rebuild social networks. Children and adolescents also had more after school opportunities, which, in turn, allowed parents, and especially mothers, to have more free time for themselves. Women were able to participate in more individual leisure activities mainly because they believed American society was more open to gender equality. However, family roles still played a vital role in their personal lives and women were still expected to put family as their top priority

Defect-Seeded Atomic Layer Deposition of Metal Oxides on the Basal Plane of 2D Layered Materials

Atomic layer deposition (ALD) on mechanically exfoliated 2D layered materials spontaneously produces network patterns of metal oxide nanoparticles in triangular and linear deposits on the basal surface. The network patterns formed under a range of ALD conditions and were independent of the orientation of the substrate in the ALD reactor. The patterns were produced on MoS2 or HOPG when either tetrakis(dimethylamido)titanium or bis(ethylcyclopentadienyl)manganese were used as precursors, suggesting that the phenomenon is general for 2D materials. Transmission electron microscopy revealed the presence, prior to deposition, of dislocation networks along the basal plane of mechanically exfoliated 2D flakes, indicating that periodical basal plane defects related to disruptions in the van der Waals stacking of layers, such as perfect line dislocations and triangular extended stacking faults networks, introduce a surface reactivity landscape that leads to the emergence of patterned deposition

Pericentromeric heterochromatin is hierarchically organized and spatially contacts H3K9me2 islands in euchromatin.

Membraneless pericentromeric heterochromatin (PCH) domains play vital roles in chromosome dynamics and genome stability. However, our current understanding of 3D genome organization does not include PCH domains because of technical challenges associated with repetitive sequences enriched in PCH genomic regions. We investigated the 3D architecture of Drosophila melanogaster PCH domains and their spatial associations with the euchromatic genome by developing a novel analysis method that incorporates genome-wide Hi-C reads originating from PCH DNA. Combined with cytogenetic analysis, we reveal a hierarchical organization of the PCH domains into distinct territories. Strikingly, H3K9me2-enriched regions embedded in the euchromatic genome show prevalent 3D interactions with the PCH domain. These spatial contacts require H3K9me2 enrichment, are likely mediated by liquid-liquid phase separation, and may influence organismal fitness. Our findings have important implications for how PCH architecture influences the function and evolution of both repetitive heterochromatin and the gene-rich euchromatin

Phase diagram study of a two-dimensional frustrated antiferromagnet via unsupervised machine learning

We apply unsupervised learning techniques to classify the different phases of the $J_1-J_2$ antiferromagnetic Ising model on the honeycomb lattice. We construct the phase diagram of the system using convolutional autoencoders. These neural networks can detect phase transitions in the system via `anomaly detection', without the need for any label or a priori knowledge of the phases. We present different ways of training these autoencoders and we evaluate them to discriminate between distinct magnetic phases. In this process, we highlight the case of high temperature or even random training data. Finally, we analyze the capability of the autoencoder to detect the ground state degeneracy through the reconstruction error.Comment: 11 pages, 15 figure

Adjuvants : an essential component of neisseria vaccines

Adjuvants may be classified into delivery systems and immune potentiator or modulator molecules based on their mechanism of action. Neisseria vaccines containing traditional adjuvants such as aluminium salts have existed for long time, but meningitis caused by Neisseria meningitidis serogroups, particularly serogroup B, continues to be a global health problem. Novel strategies have applied in silico and recombinant technologies to develop "universal" antigens (e.g. proteins, peptides and plasmid DNA) for vaccines, but these antigens have been shown to be poorly immunogenic even when alum adjuvanted, implying a need for better vaccine design. In this work we review the use of natural, detoxified, or synthetic molecules in combination with antigens to activate the innate immune system and to modulate the adaptive immune responses. In the main, antigenic and imune potentiator signals are delivered using nano-, micro-particles, alum, or emulsions. The importance of interaction between adjuvants and antigens to activate and target dendritic cells, the bridge between the innate and adaptive immune systems, will be discussed. In addition, nasal vaccine strategies based on the development of mucosal adjuvants and Neisseria derivatives to eliminate the pathogen at the site of infection provide promising adjuvants effective not only against respiratory pathogens, but also against pathogens responsible for enteric and sexually transmitted diseases