Kinetic and thermodynamic analysis of leech-derived tryptase inhibitor interaction with bovine tryptase and bovine trypsin

The interaction of leech-derived tryptase inhibitor (LDTI) with bovine liver capsule tryptase (BLCT) and bovine trypsin has been studied using both thermodynamic and kinetic approaches. Several differences were detected: (i) the equilibrium affinity of LDTI for BLCT (K-a = 8.9 x 10(5) M-1) is about 600-fold lower than that for bovine trypsin (K-a = 5.1 x 10(8) M-1); (ii) LDTI behaves as a purely non-competitive inhibitor of BLCT, while it is a purely competitive inhibitor of bovine trypsin. These functional data are compared with those previously reported for the LDTI binding to human tryptase, where tight inhibition occurs at two of the four active sites of the tetramer (K-a = 7.1 x 10(8) M-1). Amino acid sequence alignment of BLCT, human beta II-tryptase and bovine trypsin allows us to infer some possible structural basis for the observed functional differences

Factors influencing abstinence, anticipation, and delay of sex among adolescent boys in high-STI prevalence communities

Purpose Abstinence is a core pregnancy and STI prevention strategy. We explore the attitudinal, behavioral, and family contexts relating to abstinence and the decision to delay sex among adolescent boys. Methods Adolescent boys ages 14–17 were recruited from community sites using a venue-based sampling method. All eligible boys at venues were invited to participate in an electronic survey. Question items included sexual behaviors, attitudes related to sex, relationships, masculine values, and family contextual items. Results We enrolled 667 participants, age 15.7 years, of diverse ethnicity. 252 (38%) were abstinent. Abstinent participants were younger, less likely to report non-coital behaviors, and reported lower conventional masculine values. Among abstinent participants, 62% planned to delay sex, while 38% anticipated sex in the next year. Participants with lower conventional masculine values, and more religious or moral motivations for abstinence were more likely to plan to delay sex. Discussion Abstinence among boys is common, even in high STI risk communities. For these boys, abstinence appears to be a complex behavioral decision, influenced by demographic, behavioral, attitudinal and contextual factors such as age, race, non-coital sexual behaviors and masculine values. Understanding the attitudes and contexts of abstinence, including plans to delay sex, can inform the development of public health programs for early fatherhood and STI prevention

Research with Disadvantaged, Vulnerable and/or Marginalized Adolescents

Disadvantaged, vulnerable and/or marginalized adolescents (DVMAs) are individuals aged 10–19, who are excluded from social, economic and/or educational opportunities enjoyed by other adolescents in their community due to numerous factors beyond their control. These include factors at the social level (such as economic inequality, violence, stigma, racism, migration), family level (including neglect and abuse) and individual level (e.g. disability, ethnicity). DVMAs include adolescents who are immigrants or refugees; sexual minorities; orphans; incarcerated; those who have run away or been turned out of their homes following neglect and/or abuse; those who are trafficked; and those who belong to a stigmatized indigenous, ethnic, tribal or religious groups. Though gender plays an important role within each of these categories and for the group as a whole, in this brief we do not treat all girls and young women as DVMAs. As a result of their social exclusion, DVMAs suffer from health inequities, or avoidable inequalities in their health and well-being compared to the well-being of other adolescents. Research is needed to inform ways to address these inequities

A manifesto for researching entrepreneurial ecosystems

Entrepreneurial ecosystems are the focus of government economic policies around the world for their potential to generate entrepreneur-led economic development. The paper identifies key research questions and challenges to building effective public policy: (i) the limitations of existing data sources, (ii) the need to balance findings from quantitative and qualitative studies, (iii) the danger that entrepreneurial ecosystems will be just a policy fad, (iv) the narrow focus of policy and research on high tech firms and scale-ups, and (v) the need to balance research approaches between simplified models and a complex systems approach. There is a need for a better understanding of the diversity of policy contexts (level of government, country context) and model of ecosystem governance. A more granulated understanding of ecosystem thinking is required, with greater consideration of the diversity of actors and the institutional context, with more attention given to the heterogeneous nature of places and complex interactions between actors and networks. Looking to the future, the potential of new data sources and methodologies is identified. Future research should give greater consideration to the institutional context to understand how policy can better support entrepreneurial activity and the extent to which specific policies can be replicated elsewhere

The Sexual Health Needs of Adolescent Boys Involved in a Pregnancy

Objectives: Little is known about fatherhood in middle adolescence. In order to better understand their sexual health needs, we describe relationship characteristics, perception of masculinity and associated STI risk behaviors in a community-based sample of urban middle adolescent boys who have fathered a child or been involved with a pregnancy. Methods: We employed venue-based sampling to recruit 339 boys (14-17 years old) in neighborhoods with high STI prevalence. We administered a brief survey on sexual, relationship and pregnancy history, STI risk, juvenile justice involvement, and masculinity. Results: Fifteen percent had either fathered a child or been involved with a pregnancy. In multivariate analysis, controlling for age and ethnicity, adolescent fathers were more likely to be involved with juvenile justice and engage in STI risk behaviors. These included condom non-use and partner checking a cell phone. Although of borderline significance, older partners, past STI testing, and drug or alcohol use at last sex improved model fit. Conclusion: Adolescent fathers have distinct relational and sexual health needs. Their specific needs should be targeted by prevention programs. Implications and Contribution: Most research on young men involved in pregnancy is with older adolescents/young adults, and in clinical or institutional settings. Using community engagement and venue-based sampling, this study describes sexual behaviors, masculinity, and relationship characteristics among 14-17 year old boys who have caused a pregnancy. Findings identify their distinct sexual health needs

Fabrication of metallic patterns by microstencil lithography on polymer surfaces suitable as microelectrodes in integrated microfluidic systems

Microstencil lithography, i.e. local deposition of micrometer scale patterns through small shadow masks, is a promising method for metal micropattern definition on polymer substrates that cannot be structured using organic-solvent-based photoresist technology. We propose to apply microstencil lithography to fabricate microelectrodes on flat and 3D polymer substrates, such as PMMA or SU-8, which form parts of microfluidic systems with integrated microelectrodes. Microstencil lithography is accompanied by two main issues when considered for application as a low-cost, reproducible alternative to standard photolithography on polymer substrates. In this paper we assess in detail (i) the reduction of aperture size (clogging) after several metal evaporation steps and corresponding change of deposited pattern size and (ii) loss in the resolution (blurring) of the deposited microstructures when there is a several micrometers large gap between the stencil membrane and the substrate. The clogging of stencil apertures induced by titanium and copper evaporation was checked after each evaporation step, and it was determined that approximately 50% of the thickness of the evaporated metals was deposited on the side walls of the stencil apertures. The influence of a gap on the deposited structures was analyzed by using 18 um thick SU-8 spacers placed between the microstencil and the substrate. The presence of an 18 um gapmade the deposited structures notably blurred. The blurring mechanism of deposited structures is discussed based on a simplified geometrical model. The results obtained in this paper allow assessing the feasibility of using stencil-based lithography for unconventional surface patterning, which shows the limits of the proposed method, but also provides a guideline on a possible implementation for combined polymer-electrode microsystems, where standard photoresist technology fails

Pleosporales

One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae

Isolation and Maintenance-Free Culture of Contractile Myotubes from Manduca sexta Embryos

Skeletal muscle tissue engineering has the potential to treat tissue loss and degenerative diseases. However, these systems are also applicable for a variety of devices where actuation is needed, such as microelectromechanical systems (MEMS) and robotics. Most current efforts to generate muscle bioactuators are focused on using mammalian cells, which require exacting conditions for survival and function. In contrast, invertebrate cells are more environmentally robust, metabolically adaptable and relatively autonomous. Our hypothesis is that the use of invertebrate muscle cells will obviate many of the limitations encountered when mammalian cells are used for bioactuation. We focus on the tobacco hornworm, Manduca sexta, due to its easy availability, large size and well-characterized muscle contractile properties. Using isolated embryonic cells, we have developed culture conditions to grow and characterize contractile M. sexta muscles. The insect hormone 20-hydroxyecdysone was used to induce differentiation in the system, resulting in cells that stained positive for myosin, contract spontaneously for the duration of the culture, and do not require media changes over periods of more than a month. These cells proliferate under normal conditions, but the application of juvenile hormone induced further proliferation and inhibited differentiation. Cellular metabolism under normal and low glucose conditions was compared for C2C12 mouse and M. sexta myoblast cells. While differentiated C2C12 cells consumed glucose and produced lactate over one week as expected, M. sexta muscle did not consume significant glucose, and lactate production exceeded mammalian muscle production on a per cell basis. Contractile properties were evaluated using index of movement analysis, which demonstrated the potential of these cells to perform mechanical work. The ability of cultured M. sexta muscle to continuously function at ambient conditions without medium replenishment, combined with the interesting metabolic properties, suggests that this cell source is a promising candidate for further investigation toward bioactuator applications