Thin films of a dimeric ruthenium phthalocyanine complex on gold

Thin films of a new dimeric ruthenium phthalocyanine complex bearing a thioester-functionalized axial ligand were formed on gold surfaces. Characterization of the thin films by laser ablation-inductively coupled-mass spectrometry and scanning tunneling microscopy revealed that the films do not have any long-range order. © 2009 Elsevier B.V. All rights reserved

Thin films of Ruthenium Phthalocyanine complexes

Four new ruthenium phthalocyanine complexes bearing axial ligands with thioacetate groups that facilitate thin film formation on gold surfaces are presented. Scanning tunnelling microscopy (STM) images and surface coverage data obtained by solution inductively coupled plasma mass spectrometry (ICP-MS) experiments show that peripheral and axial ligand substituents on the complexes have a significant effect on their surface coverage. A laser ablation ICP-MS technique that provides information about thin films across macro-sized areas is described here for the first time. Using the technique, the maximum surface coverage of a ruthenium phthalocyanine complex was found to occur within one minute of gold substrate immersion in the complexcontaining solution

Quantification method for elemental bio-imaging by LA-ICP-MS using metal spiked PMMA films

A method for quantitative analysis of biological soft tissues by laser ablation-inductively coupled plasma-mass spectrometry has been developed. Polymer film standards were produced by spin coating spiked solutions of polymethylmethacrylate onto quartz substrates. Calibration curves throughout the range of 0-400 μg g-1 yielded correlation coefficients better than 0.999 for 66Zn and 63Cu. Spiked, homogenised soft tissue standards were quantified by LA-ICP-MS against the thin film standards. The results agreed with values calculated from solution nebulisation ICP-MS. A procedure for internal standardisation by employing ruthenium or yttrium in the underlying thin film was also assessed. © The Royal Society of Chemistry 2010

How and When Socially Entrepreneurial Nonprofit Organizations Benefit From Adopting Social Alliance Management Routines to Manage Social Alliances?

Social alliance is defined as the collaboration between for-profit and nonprofit organizations. Building on the insights derived from the resource-based theory, we develop a conceptual framework to explain how socially entrepreneurial nonprofit organizations (SENPOs) can improve their social alliance performance by adopting strategic alliance management routines. We test our framework using the data collected from 203 UK-based SENPOs in the context of cause-related marketing campaign-derived social alliances. Our results confirm a positive relationship between social alliance management routines and social alliance performance. We also find that relational mechanisms, such as mutual trust, relational embeddedness, and relational commitment, mediate the relationship between social alliance management routines and social alliance performance. Moreover, our findings suggest that different types of social alliance motivation can influence the impact of social alliance management routines on different types of the relational mechanisms. In general, we demonstrate that SENPOs can benefit from adopting social alliance management routines and, in addition, highlight how and when the social alliance management routines–social alliance performance relationship might be shaped. Our study offers important academic and managerial implications, and points out future research directions

Domestic horses (Equus caballus) discriminate between negative and positive human nonverbal vocalisations

The ability to discriminate between emotion in vocal signals is highly adaptive in social species. It may also be adaptive for domestic species to distinguish such signals in humans. Here we present a playback study investigating whether horses spontaneously respond in a functionally relevant way towards positive and negative emotion in human nonverbal vocalisations. We presented horses with positively- and negatively-valenced human vocalisations (laughter and growling, respectively) in the absence of all other emotional cues. Horses were found to adopt a freeze posture for significantly longer immediately after hearing negative versus positive human vocalisations, suggesting that negative voices promote vigilance behaviours and may therefore be perceived as more threatening. In support of this interpretation, horses held their ears forwards for longer and performed fewer ear movements in response to negative voices, which further suggest increased vigilance. In addition, horses showed a right-ear/left-hemisphere bias when attending to positive compared with negative voices, suggesting that horses perceive laughter as more positive than growling. These findings raise interesting questions about the potential for universal discrimination of vocal affect and the role of lifetime learning versus other factors in interspecific communication

Adaptive Lévy Walks in Foraging Fallow Deer

Background: Lévy flights are random walks, the step lengths of which come from probability distributions with heavy power-law tails, such that clusters of short steps are connected by rare long steps. Lévy walks maximise search efficiency of mobile foragers. Recently, several studies raised some concerns about the reliability of the statistical analysis used in previous analyses. Further, it is unclear whether Lévy walks represent adaptive strategies or emergent properties determined by the interaction between foragers and resource distribution. Thus two fundamental questions still need to be addressed: the presence of Lévy walks in the wild and whether or not they represent a form of adaptive behaviour. Methodology/Principal Findings: We studied 235 paths of solitary and clustered (i.e. foraging in group) fallow deer (Dama dama), exploiting the same pasture. We used maximum likelihood estimation for discriminating between a power-tailed distribution and the exponential alternative and rank/frequency plots to discriminate between Lévy walks and composite Brownian walks. We showed that solitary deer perform Lévy searches, while clustered animals did not adopt that strategy. Conclusion/Significance: Our demonstration of the presence of Lévy walks is, at our knowledge, the first available which adopts up-to-date statistical methodologies in a terrestrial mammal. Comparing solitary and clustered deer, we concluded that the Lévy walks of solitary deer represent an adaptation maximising encounter rates with forage resources and not a

Utilisation non médicale des médicaments d’ordonnance chez les adolescents utilisant des drogues au Québec

Abstract : OBJECTIVE: To determine the prevalence and factors associated with nonmedical use of prescription medication (NMUPM) among adolescents who use drugs (ages 12 to 17 years) in Quebec. METHOD: Secondary data analyses were carried out with data from a 6-month study, namely, the 2010-2011 Quebec Health Survey of High School Students-a large-scale survey that sought to gain a better understanding of the health and well-being of young Quebecers in high school. Bivariate and multivariate logistic regression analyses were conducted to study NMUPM among adolescents who use drugs, according to sociodemographic characteristics, peer characteristics, health indicators (anxiety, depression, or attention-deficit disorder [ADD] with or without hyperactivity), self-competency, family environment, and substance use (alcohol and drug use) factors. RESULTS: Among adolescents who had used drugs in the previous 12 months, 5.4% (95% CI 4.9% to 6.0%) reported NMUPM. Based on multivariate analyses, having an ADD (adjusted odds ratio [AOR] 1.47; 95% CI 1.13 to 1.91), anxiety disorder (AOR 2.14; 95% CI 1.57 to 2.92), low self-esteem (AOR 1.62; 95% CI 1.26 to 2.08), low self-control (AOR 1.95; 95% CI 1.55 to 2.45), low parental supervision (AOR 1.43; 95% CI 1.11 to 1.83), regular alcohol use (AOR 1.72; 95% CI 1.36 to 2.16), and polysubstance use (AOR 4.09; 95% CI 3.06 to 5.48) were associated with increased odds of reporting NMUPM. CONCLUSIONS: The observed prevalence of NMUPM was lower than expected. However, the associations noted with certain mental health disorders and regular or heavy use of other psychoactive substances are troubling. Clinical implications are discussed.OBJECTIF: Déterminer la prévalence de l’utilisation non médicale des médicaments d’ordonnance (UNMMO) et les facteurs qui y sont associés chez les adolescents (de 12 à 17 ans) qui utilisent des drogues au Québec. MÉTHODE: Des analyses de données secondaires ont été exécutées avec les données d’une étude de 6 mois, l’Enquête québécoise sur la santé des jeunes du secondaire 2010-2011, une enquête de grande envergure visant à obtenir une meilleure compréhension de la santé et du bien-être des jeunes québécois du secondaire. Des analyses de régression logistique bivariée et multivariée ont été menées pour étudier l’UNMMO chez les adolescents qui utilisent des drogues, selon les facteurs des caractéristiques sociodémographiques, des caractéristiques des pairs, des indicateurs de la santé (anxiété, dépression, ou trouble de déficit de l’attention [TDA] avec ou sans hyperactivité), de l’autoefficacité, de l’environnement familial, et de l’utilisation de substances (utilisation d’alcool et de drogues). RÉSULTATS: Parmi les adolescents qui avaient utilisé des drogues dans les 12 mois précédents, 5,4 % (IC à 95 % 4,9 % à 6,0 %) déclaraient une UNMMO. Selon les analyses multivariées, un TDA (ratio de cotes ajusté [RCC] 1,47; IC à 95 % 1,13 à 1,91), un trouble anxieux (RCC 2,14; IC à 95 % 1,57 à 2,92), une faible estime de soi (RCC 1,62; IC à 95 % 1,26 à 2,08), un faible autocontrôle (RCC 1,95; IC à 95 % 1,55 à 2,45), une faible supervision parentale (RCC 1,43; IC à 95 % 1,11 à 1,83), une utilisation d’alcool régulière (RCC 1,72; IC à 95 % 1,36 à 2,16), et une utilisation de polysubstances (RCC 4,09; IC à 95 % 3,06 à 5,48) étaient associés à des probabilités accrues de déclarer une UNMMO. CONCLUSIONS: La prévalence observée de l’UNMMO était plus faible que prévu. Cependant, les associations notées entre certains troubles de santé mentale et l’utilisation régulière ou intensive d’autres substances psychoactives sont inquiétantes. Les implications cliniques sont discutées

The what and where of adding channel noise to the Hodgkin-Huxley equations

One of the most celebrated successes in computational biology is the Hodgkin-Huxley framework for modeling electrically active cells. This framework, expressed through a set of differential equations, synthesizes the impact of ionic currents on a cell's voltage -- and the highly nonlinear impact of that voltage back on the currents themselves -- into the rapid push and pull of the action potential. Latter studies confirmed that these cellular dynamics are orchestrated by individual ion channels, whose conformational changes regulate the conductance of each ionic current. Thus, kinetic equations familiar from physical chemistry are the natural setting for describing conductances; for small-to-moderate numbers of channels, these will predict fluctuations in conductances and stochasticity in the resulting action potentials. At first glance, the kinetic equations provide a far more complex (and higher-dimensional) description than the original Hodgkin-Huxley equations. This has prompted more than a decade of efforts to capture channel fluctuations with noise terms added to the Hodgkin-Huxley equations. Many of these approaches, while intuitively appealing, produce quantitative errors when compared to kinetic equations; others, as only very recently demonstrated, are both accurate and relatively simple. We review what works, what doesn't, and why, seeking to build a bridge to well-established results for the deterministic Hodgkin-Huxley equations. As such, we hope that this review will speed emerging studies of how channel noise modulates electrophysiological dynamics and function. We supply user-friendly Matlab simulation code of these stochastic versions of the Hodgkin-Huxley equations on the ModelDB website (accession number 138950) and http://www.amath.washington.edu/~etsb/tutorials.html.Comment: 14 pages, 3 figures, review articl

Targeting the Replication Initiator of the Second Vibrio Chromosome: Towards Generation of Vibrionaceae-Specific Antimicrobial Agents

The Vibrionaceae is comprised of numerous aquatic species and includes several human pathogens, such as Vibrio cholerae, the cause of cholera. All organisms in this family have two chromosomes, and replication of the smaller one depends on rctB, a gene that is restricted to the Vibrionaceae. Given the increasing prevalence of multi-drug resistance in pathogenic vibrios, there is a need for new targets and drugs to combat these pathogens. Here, we carried out a high throughput cell-based screen to find small molecule inhibitors of RctB. We identified a compound that blocked growth of an E. coli strain bearing an rctB-dependent plasmid but did not influence growth of E. coli lacking this plasmid. This compound, designated vibrepin, had potent cidal activity against V. cholerae and inhibited the growth of all vibrio species tested. Vibrepin blocked RctB oriCII unwinding, apparently by promoting formation of large non-functional RctB complexes. Although vibrepin also appears to have targets other than RctB, our findings suggest that RctB is an attractive target for generation of novel antibiotics that only block growth of vibrios. Vibrio-specific agents, unlike antibiotics currently used in clinical practice, will not engender resistance in the normal human flora or in non-vibrio environmental microorganisms