The influence of the copper(II) ion on the formation, morphology, and organization of an arachidic acid monolayer was investigated using Langmuir–Blodgett (LB) monolayers, Π–A isotherms, and ...Brewster angle microscopy (BAM). Our findings indicate that a Cu2+-complexed LB film exhibits an order that depends on the subphase pH, analogous to other metal ions. Yazdanian, M. ; et al. Ionic Interactions of Fatty Acid Monolayers at the Air–Water Interface. Langmuir 1990, 6, 1093–1098. Kurnaz, M. L. ; et al. Morphology of Microphase Separation in Arachidic Acid–Cadmium Arachidate Langmuir–Blodgett Multilayers. J. Phys. Chem. 1996, 100, 11113–11119.The metal ion facilitates the formation of solid-phase films at surface pressures as low as 5 mN/m. The films exhibit a rigid, ordered phase, evidenced by the absence of a collapse point and an increase in surface pressure rather than the typical sharp decrease in surface pressure, indicative of film failure. Amphiphile ionic charge vs pH (i.e., the extent of arachidic acid protonation) plays a role in the observed absence of collapse and the ability of the films to maintain order and cohesion at high surface pressures (ca. 65 mN/m). Additionally, film thickness data suggest that the incorporation of Cu2+ ions induces a change in orientation of the aliphatic chains of the amphiphiles and that amphiphile solubility in the subphase may play a role in the observed film behavior at low surface areas and high pH.
The history of science has frequently included a problem-based impetus toward research that can be translated expeditiously into solutions. A current problem is that psychopathologies, typically ...chronic, contribute hugely to the economic and social burden of medical care, especially in the United States. For behavioral neuroscientists a psychopathology-aimed translational research emphasis particularly involves animal models to facilitate the experimental and invasive work necessary to an understanding of the biology of normal and aberrant behavior. When the etiology of a particular psychopathology is unknown, and there are no specific biomarkers, behavioral parallels between the focal disorder and its putative models become crucial elements in assessing model validity. Evaluation of these parallels is frequently neglected, reflecting in part the lack of a systematic conceptualization of the organization of behavior and how this may be conserved across species. Recent work specifically attempting to bridge this gap suggests that analysis of behaviors that are functional - adaptive in crucial situations such as danger or social contexts - can facilitate an understanding of the parallels between behaviors of human and nonhuman species, including the dysfunctional behaviors of psycho pathologies. As research with animal models comes to provide a more systematic analysis of particular behaviors and their adaptive functions, cross-talk between model and focal psychopathology may be advantageous to understanding both.
We report direct evidence for charge-induced long-range (ca. 100 μm) order in the room-temperature ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4 –), supported on a silica ...surface. We have measured the rotational diffusion dynamics of anionic, cationic, and neutral chromophores as a function of distance from a silica surface. The results reflect the excess charge density gradient induced in the IL by the (negative) charge present on the silica surface. Identical measurements in ethylene glycol reveal spatially invariant reorientation dynamics for all chromophores. Capping the silica support with Me2SiCl2 results in spatially invariant reorientation dynamics in the IL. We understand these data in the context of the IL exhibiting a spatially damped piezoelectric response mediated by IL fluidity and disorder.
The immune system continually battles against pathogen-induced pressures, which often leads to the evolutionary expansion of immune gene families in a species-specific manner. For example, the pals ...gene family expanded to 39 members in the Caenorhabditis elegans genome, in comparison to a single mammalian pals ortholog. Our previous studies have revealed that two members of this family, pals-22 and pals-25, act as antagonistic paralogs to control the Intracellular Pathogen Response (IPR). The IPR is a protective transcriptional response, which is activated upon infection by two molecularly distinct natural intracellular pathogens of C. elegans-the Orsay virus and the fungus Nematocida parisii from the microsporidia phylum. In this study, we identify a previously uncharacterized member of the pals family, pals-17, as a newly described negative regulator of the IPR. pals-17 mutants show constitutive upregulation of IPR gene expression, increased immunity against intracellular pathogens, as well as impaired development and reproduction. We also find that two other previously uncharacterized pals genes, pals-20 and pals-16, are positive regulators of the IPR, acting downstream of pals-17. These positive regulators reverse the effects caused by the loss of pals-17 on IPR gene expression, immunity, and development. We show that the negative IPR regulator protein PALS-17 and the positive IPR regulator protein PALS-20 colocalize inside and at the apical side of intestinal epithelial cells, which are the sites of infection for IPR-inducing pathogens. In summary, our study demonstrates that several pals genes from the expanded pals gene family act as ON/OFF switch modules to regulate a balance between organismal development and immunity against natural intracellular pathogens in C. elegans.
Anhedonia, the diminished capacity to experience pleasant emotions, is a common, treatment-resistant feature of schizophrenia that is often included among the negative symptoms of this disorder. This ...selective review describes the 3 most commonly used approaches to assess anhedonia in schizophrenia: interview-based measures, self-report trait questionnaires, and laboratory-based assessments of emotional experience. For each assessment approach, psychometric properties, relationships to other symptoms and features of schizophrenia, and relationships with the other assessment approaches are evaluated. It is concluded that anhedonia can be reliably assessed and constitutes a distinctive, clinically important aspect of schizophrenia that should be included in a comprehensive evaluation of negative symptoms. Current efforts to define more precisely the nature of the hedonic deficit in schizophrenia are discussed, and recommendations for optimal assessment of anhedonia in clinical trials of novel treatments for negative symptoms are provided.
Social interactions serve as an evolutionarily important source of stress, and one that is virtually ubiquitous among mammalian species. Animal models of social stress are varied, ranging from a ...focus on acute, intermittent, or chronic exposure involving agonistic behavior, to social isolation. The relative stressfulness of these experiences may depend on the species, sex, and age of the subjects, and subject sex also appears to influence the value of hypothalamic–pituitary–adrenal (HPA) axis activity as a general criterion for stress response: higher glucocorticoid levels are typically found in dominant females in some species. Social stress models often produce victorious and defeated, or dominant and subordinate, animals that may be compared to each other or to controls, but the appropriateness of specific types of comparisons and the interpretations of their differences may vary for the different models. Social stress strongly impacts behavior, generally reducing aggression and enhancing defensiveness, both inside and outside the stress situation. Social and sexual behaviors may be reduced in subordinate animals, as is activity and responsivity to normally rewarding events. However, some components of these changes may be dependent on the presence of a dominant, rather than representing a longer-term and general alteration in behavior. Social stress effects on brain neurotransmitter systems have been most extensively investigated, and most often found in serotonin and noradrenergic systems, with changes also reported for other monoamine and for peptidergic systems. Morphological changes and alterations of neogenesis and of cell survival particularly involving the hippocampus and dentate gyrus have been reported with severe social stress, as have longer-term changes in HPA axis functioning. These findings indicate that social stress models can provide high magnitude and appropriate stressors for research, but additionally suggest a need for caution in interpretation of the findings of these models and care in analysis of their underlying mechanisms.
We have reported previously on the existence of charge-induced long-range organization in the room-temperature ionic liquid (RTIL), BMIM+BF4 –. The induced organization is in the form of a free ...charge density gradient (ρf) that exists over ca. 100 μm into the RTIL in contact with a charged surface. The fluorescence anisotropy decay of a trace-level charged chromophore in the RTIL is measured as a function of distance from the indium-doped tin oxide support surface to probe this free charge density gradient. We report here on the characterization of the free charge density gradient in five different imidazolium RTILs and use these data to evaluate the magnitude of the induced free charge density gradient. Both the extent and magnitude of this gradient depend on the chemical structures of the cationic and anionic constituents of the RTIL used. Control over the magnitude of ρf has implications for the utility of RTILs for a host of applications that remain to be explored fully.
To understand the diverse impact of the crisis across emerging market countries, we explore the role of two shocks—the collapse in trade and the sharp decline in financial flows—in the transmission ...of the crisis from the advanced economies. We first develop a simple open economy model, which allows for imperfect capital mobility and potentially contractionary effects of currency depreciation due to foreign debt exposure. We then look at the cross-country evidence. The data suggest a strong role for both trade and financial shocks. Perhaps surprisingly, the data give little econometric support for a central role of either reserves or exchange rate regimes. We end by presenting case studies for Latvia, Russia, and Chile.
Several studies suggest an increasing prevalence of multiple sclerosis (MS) in Canada. We aimed to validate a case definition for MS using administrative health insurance data, and to describe the ...incidence and prevalence of MS in Manitoba, Canada.
We used provincial administrative claims data to identify persons with demyelinating disease using International Classification of Diseases 9/10 codes and prescription claims. To validate the case definition, questionnaires were mailed to 2,000 randomly selected persons with an encounter for demyelinating disease, requesting permission for medical records review. We used diagnoses abstracted from medical records as the gold standard to evaluate candidate case definitions using administrative data.
From 1984 to 1997, cases of MS using claims data were defined as persons with > or = 7 medical contacts for MS. From 1998 onward, cases were defined as persons with > or = 3 medical contacts. As compared to medical records, this definition had a positive predictive value of 80.5% and negative predictive value of 75.5%. From 1998 to 2006, the average age- and sex-adjusted annual incidence of MS per 100,000 population was 11.4 (95% confidence interval CI 10.7-12.0). The age-adjusted prevalence of MS per 100,000 population increased from 32.6 (95% CI 29.4-35.8) in 1984 to 226.7 (95% CI 218.1-235.3) in 2006, with the peak prevalence shifting to older age groups.
The prevalence of multiple sclerosis (MS) in Manitoba is among the highest in the world. The rising prevalence with minimally changing incidence suggests improving survival. This study supports the use of administrative data to develop case definitions and further define the epidemiology of MS.
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