Thermal degradation of Cross-Linked Polyisoprene and Polychloroprene

Polyisoprene and polychloroprene have been cross-linked either in solution or in solid state using free radical initiators. In the comparable experimental conditions higher cross-linking density was observed in the solid state process. Independent of the cross-linking method, polychloroprene tended to give a higher gel content and cross-link density than does polyisoprene. Infrared characterization of the cross-linked materials showed cis-trans isomerization occurred in the polyisoprene initiated by benzoyl peroxide, whereas no isomerization was found in the samples initiated by dicumyl peroxide. Polyisoprene does not cross-link by heating in a thermal analyzer, whereas polychloroprene easily undergoes cross-linking in such conditions. Infrared spectroscopy showed that in the case of polyisoprene, rearrangements occur upon heating which lead to the formation of terminal double bonds, while polychloroprene loses hydrogen chlorine which leads to a conjugated structure. There is apparently some enhancement of the thermal and thermal oxidative stability of polyisoprene because of the cross-linking. Cross-linked polychloroprene is less thermally stable than the virgin polymer. Cross-linking promotes polymers charring in the main step of weight loss in air, which leads to enhanced transitory char

Snake prices and crocodile appetites: Aquatic wildlife supply and demand on Tonle Sap Lake, Cambodia

Commercial trade is a major driver of over-exploitation of wild species, but the pattern of demand and how it responds to changes in supply is poorly understood. Here we explore the markets for snakes from Tonle Sap Lake in Cambodia to evaluate future exploitation scenarios, identify entry points for conservation and, more generally, to illustrate the value of multi-scale analysis of markets to traded wildlife conservation. In Cambodia, the largest driver of snake exploitation is the domestic trade in snakes as crocodile food. We estimate that farmed crocodiles consume between 2.7 and 12.2 million snakes per year. The market price for crocodiles has been in decline since 2003, which, combined with rising prices for their food, has led to a reduced frequency of feeding and closure of small farms. The large farms that generate a disproportionate amount of the demand for snakes continue to operate in anticipation of future market opportunities, and preferences for snakes could help maintain demand if market prices for crocodiles rise to pre 2003 levels. In the absence of a sustained demand from crocodile farms, it is also possible that alternative markets will develop, such as one for human snack food. The demand for snakes, however, also depends on the availability of substitute resources, principally fish. The substitutability and low price elasticity of demand offers a relatively sustainable form of consumerism. Given the nature of these market drivers, addressing consumer preferences and limiting the protection of snakes to their breeding season are likely to be the most effective tools for conservation. This study highlights the importance of understanding the structure of markets and the behaviour of consumer demand prior to implementing regulations on wildlife hunting and trade

Fis Is Essential for Capsule Production in Pasteurella multocida and Regulates Expression of Other Important Virulence Factors

P. multocida is the causative agent of a wide range of diseases of animals, including fowl cholera in poultry and wild birds. Fowl cholera isolates of P. multocida generally express a capsular polysaccharide composed of hyaluronic acid. There have been reports of spontaneous capsule loss in P. multocida, but the mechanism by which this occurs has not been determined. In this study, we identified three independent strains that had spontaneously lost the ability to produce capsular polysaccharide. Quantitative RT-PCR showed that these strains had significantly reduced transcription of the capsule biosynthetic genes, but DNA sequence analysis identified no mutations within the capsule biosynthetic locus. However, whole-genome sequencing of paired capsulated and acapsular strains identified a single point mutation within the fis gene in the acapsular strain. Sequencing of fis from two independently derived spontaneous acapsular strains showed that each contained a mutation within fis. Complementation of these strains with an intact copy of fis, predicted to encode a transcriptional regulator, returned capsule expression to all strains. Therefore, expression of a functional Fis protein is essential for capsule expression in P. multocida. DNA microarray analysis of one of the spontaneous fis mutants identified approximately 30 genes as down-regulated in the mutant, including pfhB_2, which encodes a filamentous hemagglutinin, a known P. multocida virulence factor, and plpE, which encodes the cross protective surface antigen PlpE. Therefore these experiments define for the first time a mechanism for spontaneous capsule loss in P. multocida and identify Fis as a critical regulator of capsule expression. Furthermore, Fis is involved in the regulation of a range of other P. multocida genes including important virulence factors

Full genome sequence and sfRNA interferon antagonist activity of Zika virus from Recife, Brazil

Background: The outbreak of Zika virus (ZIKV) in the Americas has transformed a previously obscure mosquito-transmitted arbovirus of the Flaviviridae family into a major public health concern. Little is currently known about the evolution and biology of ZIKV and the factors that contribute to the associated pathogenesis. Determining genomic sequences of clinical viral isolates and characterization of elements within these are an important prerequisite to advance our understanding of viral replicative processes and virus-host interactions. Methodology/Principal findings: We obtained a ZIKV isolate from a patient who presented with classical ZIKV-associated symptoms, and used high throughput sequencing and other molecular biology approaches to determine its full genome sequence, including non-coding regions. Genome regions were characterized and compared to the sequences of other isolates where available. Furthermore, we identified a subgenomic flavivirus RNA (sfRNA) in ZIKV-infected cells that has antagonist activity against RIG-I induced type I interferon induction, with a lesser effect on MDA-5 mediated action. Conclusions/Significance: The full-length genome sequence including non-coding regions of a South American ZIKV isolate from a patient with classical symptoms will support efforts to develop genetic tools for this virus. Detection of sfRNA that counteracts interferon responses is likely to be important for further understanding of pathogenesis and virus-host interactions

Towards a sustainable, participatory and inclusive wild meat sector

The meat of wild species, referred to in this report as 'wild meat', is an essential source of protein and a generator of income for millions of forest-living communities in tropical and subtropical regions. However, unsustainable harvest rates currently endanger the integrity of ecosystems and threaten the livelihoods of many vulnerable households. This report, produced in response to a call from the Secretariat of the Convention on Biological Diversity (CBD), is a technical tool to help users guide actions towards a more sustainable wild meat sector. Here, we present an extensive compilation of the current knowledge on wild meat use, drivers and impacts, and provide recommendations on how to improve wild meat governance and management. In all tropical and subtropical regions, greater wildlife offtakes are being enabled by advances in hunting technologies, as well as the increased penetration of new lands by infrastructure, logging, mining and agriculture. Consumers in fast-growing urban centers largely drive demand for wild meat, where it is eaten as a luxury item rather than as a food staple. This greater pressure from large towns and cities has had significant impacts on wildlife populations and ecosystem integrity. In turn, this jeopardizes the financial 'safety nets' and food security of remote rural and indigenous communities, for whom wild meat can account for much of their dietary protein, as well as an important source of other nutrients. Key to the success of sustainable management is ensuring that wild meat use is considered a cross-sectoral issue; firmly incorporated in national resource and land-use planning. The success of management strategies will depend on an enabling environment at the national level. In many countries a key first step will be the revision of national hunting laws and land tenure governance systems in consultation with multiple stakeholders. Research efforts must focus on producing science-based evidence that governments, communities, NGOs and industries can use to improve management policies and practices. The creation of a sustainable wild meat sector requires interconnected interventions along the entire value chain - focused on local hunting communities, urban consumers and wider society. Well-designed, participatory approaches can enable sustainable management of wild meat supply for local communities, but only if this is strongly complemented by approaches that aim to reduce urban demand

A candidate gene approach to study nematode resistance traits in naturally infected sheep

Sheep naturally acquire a degree of resistant immunity to parasitic worm infection through repeated exposure. However, the immune response and clinical outcome vary greatly between animals. Genetic polymorphisms in genes integral to differential T helper cell polarization may contribute to variation in host response and disease outcome. A total of twelve single nucleotide polymorphisms (SNPs) were sequenced in IL23R, RORC2 and TBX21 from genomic DNA of Scottish Blackface lambs. Of the twelve SNPs, six were non-synonymous (missense), four were within the 3′ UTRs and two were intronic. The association between nine of these SNPs and the traits of body weight, faecal egg count (FEC) and relative T. circumcincta L3-specific IgA antibody levels was assessed in a population of domestic Scottish Blackface ewe lambs and a population of free-living Soay ewe lambs both naturally infected with a mixture of nematodes. There were no significant associations identified between any of the SNPs and phenotypes recorded in either of the populations after adjustment for multiple testing (Bonferroni corrected P value ≤ 0.002). In the Blackface lambs, there was a nominally significant association (P = 0.007) between IL23Rp.V324M and weight at 20 weeks. This association may be worthy of further investigation in a larger sample of sheep

Quantum regression theorem for non-Markovian Lindblad equations

We find the conditions under which a quantum regression theorem can be assumed valid for non-Markovian master equations consisting in Lindblad superoperators with memory kernels. Our considerations are based on a generalized Born-Markov approximation, which allows us to obtain our results from an underlying Hamiltonian description. We demonstrate that a non-Markovian quantum regression theorem can only be granted in a stationary regime if the dynamics satisfies a quantum detailed balance condition. As an example we study the correlations of a two level system embedded in a complex structured reservoir and driven by an external coherent field.Comment: 14 pages, 5 figures. Extended version. The GBMA is deduced from projector technique. A new appendix is adde

Student Employment: Linking College and the Workplace

The focus of National Student Employment Association (formerly the National Association of Student Employment Administrators, or NASEA) publications has always been on students in transition. From the freshman moving from high school to higher education, to the senior attempting the transition to professional employment and financial independence, we always have explored how students can better accomplish these linking experiences. Student employment is a hybrid, serving as a bridge between work and school, and ultimately, a link between school and full-time work. Student employment links elements of financial aid, career development, academic learning, experiential education, and personal development. Student employment, in all of these ways, is a bridge, moving the student from point A to point B. Because of this variety, any publication on student employment must necessarily speak to diverse themes. We have organized this publication in four sections: an introduction followed by three themed sections.https://digitalcommons.brockport.edu/bookshelf/1000/thumbnail.jp

Regulators of G protein Signaling (RGS) proteins (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Regulators of G protein signalling (RGS) proteins display a common RGS domain that interacts with the GTP-bound Gα subunits of heterotrimeric G proteins, enhancing GTP hydrolysis by stabilising the transition state [29, 419, 418], leading to a termination of GPCR signalling. Interactions through protein:protein interactions of many RGS proteins have been identified for targets other than heteromeric G proteins. Sequence analysis of the 20 RGS proteins suggests four families of RGS: RZ, R4, R7 and R12 families. Many of these proteins have been identified to have effects other than through targetting G proteins. Included here is RGS4 for which a number of pharmacological inhibitors have been described