Temperature dependence of ultrafast phonon dynamics in graphite

Nonequilibrium optical phonons are generated in graphite following the excitation of electron-hole pairs with a femtosecond laser pulse. Their energy relaxation is probed by means of terahertz pulses. We find that the hot-phonon lifetime increases by a factor of 2 when the sample temperature decreases from 300 to 5 K. These results suggest that the energy relaxation in graphite at room temperature and above is dominated by the anharmonic decay of hot A′1phonons at the K point into acoustic phonons with energies of about 10 meV

Baeyer-Villiger Monooxygenases:Tunable Oxidative Biocatalysts

Pollution, accidents, and misinformation have earned the pharmaceutical and chemical industry a poor public reputation, despite their undisputable importance to society. Biotechnological advances hold the promise to enable a future of drastically reduced environmental impact and rigorously more efficient production routes at the same time. This is exemplified in the Baeyer-Villiger reaction, which offers a simple synthetic route to oxidize ketones to esters, but application is hampered by the requirement of hazardous and dangerous reagents. As an attractive alternative, flavin-containing Baeyer-Villiger monooxygenases (BVMOs) have been investigated for their potential as biocatalysts for a long time, and many variants have been characterized. After a general look at the state of biotechnology, we here summarize the literature on biochemical characterizations, mechanistic and structural investigations, as well as enzyme engineering efforts in BVMOs. With a focus on recent developments, we critically outline the advances toward tuning these enzymes suitable for industrial applications

Observation of inhibited electron-ion coupling in strongly heated graphite

Creating non-equilibrium states of matter with highly unequal electron and lattice temperatures (Tele≠Tion) allows unsurpassed insight into the dynamic coupling between electrons and ions through time-resolved energy relaxation measurements. Recent studies on low-temperature laser-heated graphite suggest a complex energy exchange when compared to other materials. To avoid problems related to surface preparation, crystal quality and poor understanding of the energy deposition and transport mechanisms, we apply a different energy deposition mechanism, via laser-accelerated protons, to isochorically and non-radiatively heat macroscopic graphite samples up to temperatures close to the melting threshold. Using time-resolved x ray diffraction, we show clear evidence of a very small electron-ion energy transfer, yielding approximately three times longer relaxation times than previously reported. This is indicative of the existence of an energy transfer bottleneck in non-equilibrium warm dense matter

Toxicity of lunar dust

The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of substantial research efforts, lunar dust properties, and therefore lunar dust toxicity may differ substantially. In this contribution, past and ongoing work on dust toxicity is reviewed, and major knowledge gaps that prevent an accurate assessment of lunar dust toxicity are identified. Finally, a range of studies using ground-based, low-gravity, and in situ measurements is recommended to address the identified knowledge gaps. Because none of the curated lunar samples exist in a pristine state that preserves the surface reactive chemical aspects thought to be present on the lunar surface, studies using this material carry with them considerable uncertainty in terms of fidelity. As a consequence, in situ data on lunar dust properties will be required to provide ground truth for ground-based studies quantifying the toxicity of dust exposure and the associated health risks during future manned lunar missions.Comment: 62 pages, 9 figures, 2 tables, accepted for publication in Planetary and Space Scienc

A Decline in CCL3-5 Chemokine Gene Expression during Primary Simian-Human Immunodeficiency Virus Infection

BACKGROUND: The CC-chemokines CCL3, CCL4 and CCL5 have been found to block the entry of CCR5-tropic HIV into host cells and to suppress the viral replication in vitro, but the in vivo role of endogenous CC-chemokines in HIV-1 infection is still incompletely understood. METHODOLOGY/PRINCIPLE FINDINGS: In this study, the primate host CCL3, CCL4 and CCL5 gene expression was evaluated in response to simian-human immunodeficiency virus (SHIV) infection in rhesus macaque model. Five rhesus macaques were inoculated with CCR5-tropic SHIV(SF162P4). The mRNA levels of CCL3, CCL4 and CCL5 were measured by real-time PCR at post inoculation day (PID) 0, 7, 14, 21, 35, 56 and 180 in peripheral blood. In addition, a selected subset of samples from CXCR4-tropic SHIV(Ku1)-infected macaques was included with objective to compare the differences in CC-chemokine down-regulation caused by the two SHIVs. Gut-associated lymphoid tissues (GALT) collected from SHIV(SF162P4)-infected animals were also tested by flow cytometry and confocal microscopy to corroborate the gene expression results. Predictably, higher viral loads and CD4+ T cell losses were observed at PID 14 in macaques infected with SHIV(Ku1) than with SHIV(SF162P4). A decline in CC-chemokine gene expression was also found during primary (PID 7-21), but not chronic (PID 180) stage of infection. CONCLUSIONS: It was determined that A) SHIV(SF162P4) down-regulated the CC-chemokine gene expression during acute stage of infection to a greater extent (p<0.05) than SHIV(Ku1), and B) such down-regulation was not paralleled with the CD4+ T cell depletion. Evaluation of CC-chemokine enhancing immunomodulators such as synthetic CpG-oligonucleotides could be explored in future HIV vaccine studies

Animal welfare attitudes: Effects of gender and diet in university samples from 22 countries

Animal Welfare Attitudes (AWA) are defined as human attitudes towards the welfare of animals in different dimensions and settings. Demographic factors, such as age and gender are associated with AWA. The aim of this study was to assess gender differences among university students in a large convenience sample from twenty-two nations in AWA. A total of 7914 people participated in the study (5155 women, 2711 men, 48 diverse). Participants completed a questionnaire that collected demographic data, typical diet and responses to the Composite Respect for Animals Scale Short version (CRAS-S). In addition, we used a measure of gender empowerment from the Human Development Report. The largest variance in AWA was explained by diet, followed by country and gender. In terms of diet, 6385 participants reported to be omnivores, 296 as pescatarian, 637 ate a vegetarian diet and 434 were vegans (n = 162 without answer). Diet was related with CRAS-S scores; people with a vegan diet scored higher in AWA than omnivores. Women scored significantly higher on AWA than men. Furthermore, gender differences in AWA increased as gender inequality decreased

Learning Opportunities and Outcomes in Citizen Science: A Heuristic Model for Design and Evaluation

Growing numbers of Citizen Science (CS) projects focus on learning about science through the collaboration of professional scientists and citizen scientists. However, resources for the design and evaluation of CS projects in terms of learning about science are scarce. Therefore, this chapter aims to provide a model for the heuristic analysis of the supply and use of learning opportunities in CS and apply it to different CS projects. We hope that the design of future CS projects considers the MODEL-CS as an approach to enable as many participants with different prerequisites as possible to take advantage of the learning opportunities provided

Integrating institutional and behavioural measures of bribery

Bribery involves individuals exchanging material benefits for a service of a public institution. To understand the process of bribery we need to integrate measures of individual behaviour and institutional attributes rather than rely exclusively on surveys of individual perceptions and experience or macro-level corruption indexes national institutions. This paper integrates institutional and behavioural measures to show that where you live and who you are have independent influence on whether a person pays a bribe. The analysis of 76 nationwide Global Corruption Barometer surveys from six continents provides a date set in which both institutional and individual differences vary greatly. Multi-level multivariate logit analysis is used to test hypotheses about the influence of institutional context and individual contact with public services, socio-economic inequalities and roles, and conflicting behavioural and ethical norms. It finds that path-determined histories of early bureaucratization or colonialism have a major impact after controlling for individual differences. At the individual level, people who frequently make use of public services and perceive government as corrupt are more likely to pay bribes, while socio-economic inequality has no significant influence. While institutional history cannot be changed, changing the design of public services offers is something that contemporary governors could do to reduce the vulnerability of their citizens to bribery

Animal Welfare Attitudes: Effects of Gender and Diet in University Samples from 22 Countries

Animal Welfare Attitudes (AWA) are defined as human attitudes towards the welfare of animals in different dimensions and settings. Demographic factors, such as age and gender are associated with AWA. The aim of this study was to assess gender differences among university students in a large convenience sample from twenty-two nations in AWA. A total of 7914 people participated in the study (5155 women, 2711 men, 48 diverse). Participants completed a questionnaire that collected demographic data, typical diet and responses to the Composite Respect for Animals Scale Short version (CRAS-S). In addition, we used a measure of gender empowerment from the Human Development Report. The largest variance in AWA was explained by diet, followed by country and gender. In terms of diet, 6385 participants reported to be omnivores, 296 as pescatarian, 637 ate a vegetarian diet and 434 were vegans (n = 162 without answer). Diet was related with CRAS-S scores; people with a vegan diet scored higher in AWA than omnivores. Women scored significantly higher on AWA than men. Furthermore, gender differences in AWA increased as gender inequality decreased