Molecular analysis of the SNF8 gene of Saccharomyces cerevisiae

Mutations in the SNF8 gene impair derepresson of the SUC2 gene, encoding invertase, in response to glucose limitation of Saccharomyces cerevisiae. We report here the cloning of the SNF8 gene by complementation. Sequence analysis predicts a 26 936-dalton product. Disruption of the chromosomal locus caused a five-fold decrease in invertase derepression, defective growth on raffinose, and a sporulation defect in homozygous diploids. Genetic analysis of the interactions of the snf8 null mutation with spt6/ssn20 and ssn6 suppressors distinguished SNF8 from the groups, SNF1, SNF4 and SNF2, SNF5, SNF6. Notably, the snf8 ssn6 double mutants were extremely sick. Mutations of SNF8 and SNF7 showed similar phenotypes and genetic interactions, and the double mutant combination caused no additional phenotypic impairment. These findings suggest that SNF7 and SNF8 are functionally related. The complete nucleotide sequence of SNF8 has been deposited in GenBank under accession number U10361.     

Social and emotional patterns in adulthood: Support for socioemotional selectivity theory.

Explored 2 hypotheses derived from socioemotional selectivity theory: (1) Selective reductions in social interaction begin in early adulthood, and (2) emotional closeness to significant others increases rather than decreases in adulthood even when rate reductions occur. Transcribed interviews with 28 women and 22 men from the Child Guidance Study, conducted over 34 yrs, were reviewed and rated for frequency of interaction, satisfaction with the relationship, and degree of emotional closeness in 6 types of relationships. Interaction frequency with acquaintances and close friends declined from early adulthood on. Interaction frequency with spouses and siblings increased across the same time period, and emotional closeness increased throughout adulthood in relationships with relatives and close friends. Findings suggest that individuals begin narrowing their range of social partners long before old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Editorial: Smart Objects and Technologies for Social Good (GOODTECHS 2017)

Mobile Networks and Applications -     

Challenging Google Search filter bubbles in social and political information: Disconforming evidence from a digital methods case study

This article engages in the debate on supposed online ‘filter bubbles’ by analysing a panel of Google users’ search results on a standardized set of socio-politically themed search queries. In general, the query results appear to be dominated by mainstream media sources, followed at a large distance by civil society and government resources. By means of mixed model regression analyses, with the prominence of different source types in the search results as dependent variables, it was tested whether search results vary across Google Search users. The results indicate that the inclusion of participants as a random effect does not explain variance when controlling for the different query keywords and the time at which the queries were ran. Hence, this study does not support the occurrence of ‘filter bubbles’ in Google Search results in the context of social and political information.     

Structure of His94->Asp carbonic anhydrase II in a new crystalline form reveals a partially occupied zinc binding site

The structure of histidine 94aspartate (H94D) carbonic anhydraseII (CAII) crystallized in an orthorhombic space group has beendetermined to 2.5 Å resolution. This crystal form is notisomorphous with monoclinic wild-type enzyme crystals or withthe monoclinic crystal form of H94D CAII reported earlier [Kiefer,L.L.,Ippolito,J.A., Fierke,C.A. and Christianson,D.W. (1993) J. Am.Chem. Soc., 115, 12581–12582]. In monoclinic H94D CAII,a fully occupied zinc ion is tetrahedrally coordinated by D94,H96, H119 and a water molecule. In orthorhombic H94D CAII, apartially occupied zinc ion is coordinated by H96 and H119 andonly weakly coordinated by a disordered D94 side chain.Thesedifferences are particularly surprising given that the two crystalforms co-precipitate in the same drop in the same experiment.Re-refinement of the orthorhombic crystal form of H94C CAIIand comparison with its corresponding monoclinic crystal formyield similar results. It appears that partial—but notfull—zinc dissociation accompanies the crystallizationof CAII variants in the orthorhombic crystal form, and significantdifferences on the protein surface presumably affect the relativestability of each crystal lattice. These results underscoreanunexpected ambiguity in this protein engineering experiment:which crystal structure of H94D CAII should be correlated withfunctional measurements made in solution?     

Modeling biological gradient formation: combining partial differential equations and Petri nets

Both Petri nets and differential equations are important modeling tools for biological processes. In this paper we demonstrate how these two modeling techniques can be combined to describe biological gradient formation. Parameters derived from partial differential equation describing the process of gradient formation are incorporated in an abstract Petri net model. The quantitative aspects of the resulting model are validated through a case study of gradient formation in the fruit fly.     

Polypyrrole: A drug-eluting membrane for coronary stents

An approach to reducing restenosis after coronary angioplasty is the use of drug-eluting stents (DES), which release, usually over a period of 1 month, a bioactive molecule that interferes with the biological processes responsible for restenosis. Given its biocompatibility and ease of electrochemical synthesis in aqueous medium, we investigated the viability of polypyrrole (pPy) directly electrosynthesized on a metal surface in the presence of an anionic drug as electrolyte. The drug, which is incorporated during the electrosynthesis of p-doped polypyrrole, remains partly entrapped after the discharge of the polymer to the neutral form and can then be released over several days, a suitable time range for drug-eluting stents.     

Irregularly shaped DSC exotherms in the analysis of polymer crystallization

Summary This article details a study of irregularly shaped DSC exotherms of poly(3-hydroxybutyrate) (PHB) developed during isothermal and non-isothermal crystallization. Due to the extreme purity of the polymer, PHB crystallization is mainly initiated by homogeneous nucleation, with the formation of very large spherulites, especially under slow nucleation conditions. When the number of growing spherulites is low, the evolution of latent heat is very sensitive to every act of nucleation as well as to the space limitations in the process of growth, resulting in non-monotonous development of latent heat, with sudden increases and decreases in crystallization rates. This results in non conventional DSC exotherms, under given crystallization conditions, characterized by spikes or shoulders associated to nucleation of new spherulites.     

The effect of image compression on synthetic PROBA-V images

We have carried out an in-depth investigation into the effects of image compression on synthetic Probe for On-Board Autonomy – Vegetation (PROBA-V) scenes and Landsat-derived image tiles. The two image compression implementations used were the TER implementation and a bespoke implementation of the Consultative Committee for Space Data Systems (CCSDS) Blue Book standard, which are functionally identical but operate on different image architectures. This work included (1) the development of an approach for producing synthetic scenes that were appropriate in terms of structure and content, and (2) evaluation of the image compression approach on the two kinds of image in terms of their usefulness for land-cover mapping. The synthetic image (SI) generation approach has been rigorously tested and produces images that are statistically similar to real scenes, both compressed and uncompressed. The results of our work show that the effects of image compression vary significantly between bands and with different compression ratios, and that the impact of image compression on image quality does vary with spatial scale. We also found indications of increased error rate at boundaries within the imagery. While the SI generation process and the processing chain of this imagery are not completely consistent with PROBA-V imagery, agreement was found among many of the results produced by the two approaches.