A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products

The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important structural element found in many complex natural products and pharmaceuticals. Owing to the continual discovery of new guanidinecontaining natural products and designed small molecules, rapid and efficient guanidinylation methods are of keen interest to synthetic and medicinal organic chemists. Because the nucleophilicity and basicity of guanidines can affect subsequent chemical transformations, traditional, indirect guanidinylation is typically pursued. Indirect methods commonly employ multiple protection steps involving a latent amine precursor, such as an azide, phthalimide, or carbamate. By circumventing these circuitous methods and employing a direct guanidinylation reaction early in the synthetic sequence, it was possible to forge the linear terminal guanidine containing backbone of clavatadine A to realize a short and streamlined synthesis of this potent factor XIa inhibitor. In practice, guanidine hydrochloride is elaborated with a carefully constructed protecting array that is optimized to survive the synthetic steps to come. In the preparation of clavatadine A, direct guanidinylation of a commercially available diamine eliminated two unnecessary steps from its synthesis. Coupled with the wide variety of known guanidine protecting groups, direct guanidinylation evinces a succinct and efficient practicality inherent to methods that find a home in a synthetic chemist\u27s toolbox

Developing a second, third, and fourth grade environmental unit on water education

Past research into the ability of students to 'bounce back' from everyday academic setback (academic buoyancy) has lacked sensitivity to the contexts in which children demonstrate this behavior. Here we aimed to contextualize past findings by reporting the results of an exploratory investigation that featured: (1) repeated measurement of students' self-reported buoyancy across English, mathematics, science, and physical education; (2) measures of students' psychological appraisal as a test of external validity; (3) a novel national context (England rather than Australia). In total 260 English secondary school students aged 11-16. years completed self-report questionnaires. Students were found to hold relatively consistent views about their ability to bounce back from everyday academic setbacks (e.g., negative feedback, poor results, study stress or pressure) compared to the relatively less consistent views they held regarding the difficulty of the four school subjects as well as corresponding personal competences and effort. These results are discussed in the context of past research, the implications for interventions, and the need for further confirmatory investigations

The instability of planetary systems in binaries: how the Kozai mechanism leads to strong planet-planet interactions

In this letter we consider the evolution of a planetary system around a star inside a wide binary. We simulate numerically the evolution of the planetary orbits for both co-planar and highly-inclined systems. We find that the Kozai mechanism operates in the latter case. This produces a highly eccentric outer planet whose orbit crosses those of some of the inner planets. Strong planet-planet interactions then follow resulting in the ejection of one or more planets. We note that planetary systems resembling our solar system, formed around single stars in stellar clusters may exchange into binaries and thus will be vulnerable to planet stripping. This process will reduce the number of solar-system like planetary systems, and may produce at least some of the observed extra-solar planets.Comment: 5 pages, 2 figures, accepted for publication in MNRAS Letter

Academic buoyancy, student's achievement, and the linking role of control: A cross-lagged analysis of high school students

Background Previous research has indicated that although academic buoyancy and student's achievement are associated, the relationship is relatively modest. Aims We sought to determine whether another construct might link academic buoyancy and student's achievement. Based on prior theoretical and empirical work, we examined a sense of control as one possible linking mechanism. Sample The study analysed data from 2,971 students attending 21 Australian high schools. Methods We conducted a cross-lagged panel design as a first means of disentangling the relative salience of academic buoyancy, control, and achievement (Phase 1). Based upon these results, we proceeded with follow-up analyses of an ordered process model linking the constructs over time (Phase 2). Results Findings showed that buoyancy and achievement were associated with control over time, but not with one another (Phase 1). In addition, control appeared to play a role in how buoyancy influenced achievement and that a cyclical process may operate among the three factors over time (Phase 2). Conclusion The findings suggest that control may play an important role in linking past experiences of academic buoyancy and achievement to subsequent academic buoyancy and achievement.The authors would like to thank the Australian Research Council for funding this research

Is our Sun a Singleton?

Most stars are formed in a cluster or association, where the number density of stars can be high. This means that a large fraction of initially-single stars will undergo close encounters with other stars and/or exchange into binaries. We describe how such close encounters and exchange encounters can affect the properties of a planetary system around a single star. We define a singleton as a single star which has never suffered close encounters with other stars or spent time within a binary system. It may be that planetary systems similar to our own solar system can only survive around singletons. Close encounters or the presence of a stellar companion will perturb the planetary system, often leaving planets on tighter and more eccentric orbits. Thus planetary systems which initially resembled our own solar system may later more closely resemble some of the observed exoplanet systems.Comment: 2 pages, 1 figure. To be published in the proceedings of IAUS246 "Dynamical Evolution of Dense Stellar Systems". Editors: E. Vesperini (Chief Editor), M. Giersz, A. Sill

The influence of different forms of early childcare on children's emotional and behavioural development at school entry

Background: Over the past few decades there has been a dramatic increase in maternal employment and, as a result, an increase in the use of non-maternal childcare in the early years. The purpose of this longitudinal study was to examine, in a large representative English sample, the influence of different forms of childcare on children's behavioural and emotional development around the age of school entry. Methods: A sample of 991 families, originally recruited when the children were 3 months old, was assessed around school entry age at 51 months. The main outcome variable was the children's emotional and behavioural functioning, measured by questionnaire completed by both mothers and teachers. A range of repeated assessments were carried out at different time points, including direct observation of the quality of maternal caregiving and observations of the quality of non-parental care, and amount of time spent in different forms of care. Results: The strongest and most consistent influences on behaviour and emotional problems were derived from the home, including lower socio-demographic status, poorer maternal caregiving, parental stress/maternal mental health problems, as well as child gender (being a boy). Non-parental childcare had small effects on child outcome. One finding that did emerge was that children who spent more time in group care, mainly nursery care, were more likely to have behavioural problems, particularly hyperactivity. Conclusions: These findings suggest that interventions to enhance children's emotional and behavioural development might best focus on supporting families and augmenting the quality of care in the home

Ideal cardiovascular health and psychosocial risk factors among Finnish female municipal workers

Aims: Ideal cardiovascular health has been defined by the American Heart Association as the absence of disease and the presence of seven key health factors and behaviours. However, little is known about the mental aspects associated with ideal cardiovascular health metrics. The objective of this study was to assess the relationships between psychosocial risk factors and ideal cardiovascular health metrics among Finnish women at municipal work units. Method: A cross-sectional study was conducted in Finland among 732 female employees (mean +/- SD age 48 +/- 10 years) from ten work units in 2014. Ideal cardiovascular health metrics were evaluated with a physical examination, laboratory tests, medical history and self-administrated questionnaires. Psychosocial risk factors (social isolation, stress, depressive symptoms, anxiety, hostility and type D personality) were assessed with core questions as suggested by the European Society of Cardiology. Results: The prevalence of having 5-7 ideal cardiovascular health metrics was 183 (25.0%), of whom 54.1% had at least one psychosocial risk factor. Anxiety (31.3%), work stress (30.7%) and type D personality (26.1%) were the most prevalent of the psychosocial risk factors. The prevalence of depressive symptoms (pPeer reviewe

Characterization of surface films that develop on pre-oxidized copper in anoxic simulated groundwater with sulphide

Surface films formed on pre-oxidized copper in anoxic simulated groundwater with sulphide were characterized by field emission gun scanning electron microscopy (FEG-SEM), Fourier transform infrared spectroscopy (FT-IR), open circuit potential (OCP) measurements, and via analysing the water chemistry and weight changes in the specimens. Additionally, films developed under identical conditions on pre-oxidized and ground copper specimens were characterized by glow discharge optical emission spectroscopy (GDOES). The results revealed that the sulphide content in the groundwater significantly influences the morphology, composition and thickness of the surface film. The build-up of Cu2S was evidenced at the sulphide contents of 32 mg/L and 320 mg/L. GDOES depth profiling revealed that sulphur and oxygen coexisted in the film all through its thickness, yet the surface was essentially rich in sulphur. The results from characterization are presented in detail in this paper and discussed from the perspective of capabilities of the used methods

The role of psychosocial risk factors in the burden of headache

Purpose: Psychosocial risk factors are common in headache patients and affect the impact of headache in multiple ways. The aim of our study was to assess how psychosocial risk factors correlate with the headache impact test-6 (HIT-6). To our knowledge this is the first study to evaluate the impact of several psychosocial factors on the HIT-6 score. Patients and methods: Our study population consisted of 469 Finnish female employees reporting headache during the past year. Psychosocial risk factors were assessed using validated, self-administered questionnaires: the generalized anxiety disorder 7-item scale (GAD-7) for anxiety, the major depression inventory (MDI) for depressive symptoms, the ENRICHD short social support instrument (ESSI) for social isolation, the cynical distrust scale for hostility and the Bergen burnout indicator (BBI-15) for work stress. Results: Exploratory factor analysis of the HIT-6 scores revealed two factors, one describing psychological and quality of life aspects affected by headache and the other describing severity of pain and functional decline. Internal consistency of the HIT-6 was 0.87 (95% CI: 0.85-0.89). Correlations between the total HIT-6 score and all measured psychosocial risk factors except for hostility were weak, but statistically significant. Conclusion: The HIT-6 questionnaire has good construct validity and it describes reliably and independently the impact of headache without interference of psychosocial factors in general working-aged female population.Peer reviewe