Self-assembly behavior of colistin and its prodrug colistin methanesulfonate : implications for solution stability and solubilization

Colistin is an amphiphilic antibiotic that has re-emerged into clinical use due to the increasing prevalence of difficult-to-treat Gram-negative infections. The existence of self-assembling colloids in solutions of colistin and its derivative prodrug, colistin methanesulfonate (CMS), was investigated. Colistin and CMS reduced the air−water interfacial tension, and dynamic light scattering (DLS) studies showed the existence of 2.07 ± 0.3 nm aggregates above 1.5 mM for colistin and of 1.98 ± 0.36 nm aggregates for CMS above 3.5 mM (mean ± SD). Above the respective critical micelle concentrations (CMC) the solubility of azithromycin, a hydrophobic antibiotic, increased approximately linearly with increasing surfactant concentration (5:1 mol ratio colistin:azithromycin), suggestive of hydrophobic domains within the micellar cores. Rapid conversion of CMS to colistin occurred below the CMC (60% over 48 h), while conversion above the CMC was less than 1%. The formation of colistin and CMS micelles demonstrated in this study is the proposed mechanism for solubilization of azithromycin and the concentration-dependent stability of CMS.

Impact of an empowerment-based parent education program on the reduction of youth suicide risk factors

Purpose: To evaluate the impact of parent education groups on youth suicide risk factors. The potential for informal transmission of intervention impacts within school communities was assessed.

Methods: Parent education groups were offered to volunteers from 14 high schools that were closely matched to 14 comparison schools. The professionally led groups aimed to empower parents to assist one another to improve communication skills and relationships with adolescents. Australian 8th-grade students (aged 14 years) responded to classroom surveys repeated at baseline and after 3 months. Logistic regression was used to test for intervention impacts on adolescent substance use, deliquency, self-harm behavior, and depression. There were no differences between the intervention (n = 305) and comparison (n = 272) samples at baseline on the measures of depression, health behavior, or family relationships.

Results: Students in the intervention schools demonstrated increased maternal care (adjusted odds ratio [AOR] 1.9), reductions in conflict with parents (AOR .5), reduced substance use (AOR .5 to .6), and less delinquency (AOR .2). Parent education group participants were more likely to be sole parents and their children reported higher rates of substance use at baseline. Intervention impacts revealed a dose-response with the largest impacts associated with directly participating parents, but significant impacts were also evident for others in the intervention schools. Where best friend dyads were identified, the best friend’s positive family relationships reduced subsequent substance use among respondents. This and other social contagion processes were posited to explain the transfer of positive impacts beyond the minority of directly participating families.

Conclusions: A whole-school parent education intervention demonstrated promising impacts on a range of risk behaviors and protective factors relevant to youth self-harm and suicide.

Self-assembly and film stability of a micelle of a single-chain quaternary ammonium amphiphile containing azobenzene on mica

The self-assembling behavior of a single-chain quaternary ammonium amphiphile bearing azobenzene (C₁₂AzoC₆N⁺) on freshly cleaved mica sheet has been investigated by atomic force microscopy (AFM) method. Confocal microscopic Raman spectra confirm the adsorption of the self-assembled monolayer structure. Ex-situ AFM reveals that C₁₂AzoC₆N⁺ forms branch-like stripes indicating the fusion and reorganization of the micelles during drying in air as the in-situ AFM has revealed that surfactant forms spherical micelles on the mica surface. The nano-sized surface structure is strongly dependent on the change of molecular structure, which resulted from photo-induced isomerization. The nano-sized stripe is quite stable even being annealed at 90 °C for 4 h.

Suicidal intent within an acute Australian self-harming cohort

The relationship between predisposing risk factors and precipitating life events of individuals presenting to an emergency department with Deliberate Self-Harm was investigated. Poor mental health and childhood abuse were related to suicide intent, only individuals' perceptions regarding their current life events were directly associated with lethality of the self-harm act. The portfolio illustrates the issues inherent in the treatment and management of schizophrenia and the potential of CBT in addressing symptoms and sequelae of acute psychosis. Four case studies are presented.

Self-injury and eating pathology

It was found that Urgency and lack of Perseverance were significantly elevated in women with self-injury or eating pathology, and significantly higher again in women with both these syndromes. A longitudinal design found that self-injury tends to progress from milder, compulsive forms, to more severe, impulsive forms over time. The portfolio examines the frequent co-occurrence of substance use and psychiatric disorders (Dual Diagnosis). Four primary conceptualisations of how dual diagnoses develop and present are discussed. These models are then applied to inform four case studies.

The natural history of self-harm from adolescence to young adulthood : a population-based cohort study

Background Knowledge about the natural history of self-harm is scarce, especially during the transition from adolescence to young adulthood, a period characterised by a sharp rise in self-inflicted deaths. From a repeated measures cohort of a representative sample, we describe the course of self-harm from middle adolescence to young adulthood.

Methods A stratified, random sample of 1943 adolescents was recruited from 44 schools across the state of Victoria, Australia, between August, 1992, and January, 2008. We obtained data pertaining to self-harm from questionnaires and telephone interviews at seven waves of follow-up, commencing at mean age 15·9 years (SD 0·49) and ending at mean age 29·0 years (SD 0·59). Summary adolescent measures (waves three to six) were obtained for cannabis use, cigarette smoking, high-risk alcohol use, depression and anxiety, antisocial behaviour and parental separation or divorce.

Findings 1802 participants responded in the adolescent phase, with 149 (8%) reporting self-harm, More girls (95/947 [10%]) than boys (54/855 [6%]) reported self-harm (risk ratio 1·6, 95% CI 1·2–2·2). We recorded a substantial reduction in the frequency of self-harm during late adolescence. 122 of 1652 (7%) participants who reported self-harm during adolescence reported no further self-harm in young adulthood, with a stronger continuity in girls (13/888) than boys (1/764). During adolescence, incident self-harm was independently associated with symptoms of depression and anxiety (HR 3·7, 95% CI 2·4–5·9), antisocial behaviour (1·9, 1·1–3·4), high-risk alcohol use (2·1, 1·2–3·7), cannabis use (2·4, 1·4–4·4), and cigarette smoking (1·8, 1·0–3·1). Adolescent symptoms of depression and anxiety were clearly associated with incident self-harm in young adulthood (5·9, 2·2–16).

Interpretation Most self-harming behaviour in adolescents resolves spontaneously. The early detection and treatment of common mental disorders during adolescence might constitute an important and hitherto unrecognised component of suicide prevention in young adults.

Funding National Health and Medical Research Council, Australia, and operational infrastructure support programme, Government of Victoria, Australia.

Measuring self-care in chronic heart failure : a review of the psychometric properties of clinical instruments

Background : Improved self-care skills and behaviors are an important outcome of patient education and counseling. Both researchers and health professionals need to utilize instruments that are reliable and valid at measuring this outcome to advance our understanding as to the efficacy of clinical practice directed toward improving self-care.

Objective : The aim of this study was to identify instruments that measure chronic heart failure (CHF) self-care and demonstrate their psychometric properties.

Methods : A search of Medline, Cumulative Index to Nursing and Allied Health Literature, Medline, PsycArticles, Psychology and Behavioral Sciences Collection, and PsycINFO databases elucidated studies published between January 1980 and February 2009 that measure CHF self-care. The clinical instruments selected were disease-specific measures of CHF self-care behaviors that are promoted in best practice guidelines. Only instruments that reported estimates of reliability and validity were included in this review. Psychometric properties of the instruments were evaluated according to practice guidelines.

Results : The literature search identified 14 instruments published in peer-reviewed journals that measured constructs that predict or correlate to self-care rather than self-care itself. Only 2 disease-specific measures of self-care were identified (Self-care Heart Failure Index [SCHFI] and European Heart Failure Self-care Behavior Scale [EHFScBS]) that have undergone rigorous psychometric testing in CHF populations. Five aspects of validity had been demonstrated with EHFScBS, and 6 aspects of validity had been demonstrated with SCHFI. Two of 3 aspects of reliability have been demonstrated in both instruments.

Conclusion : Only 2 reliable and valid tools have been developed to specifically measure CHF self-care. Further use of these instruments in the research arena may reduce gaps in our understanding of CHF self-care and further shape clinical practice directed at improving it.

Is optimistic bias influenced by control or delay?

Optimistic bias is a commonly observed but poorly explained phenomenon. Our aim was to determine whether optimistic bias varied according to the nature of the event. Two event characteristics were explored: control and delay. A sample of 100 participants aged 18–30 years was randomly selected from the local residential telephone directory. Respondents were interviewed over the telephone. The highly structured interview schedule assessed respondents' perceptions of their own risk, and the risk of an average person of their age and sex for experiencing four negative life events: developing skin cancer, being involved in a serious car accident as the driver, being involved in a serious car accident as a passenger and having to wear a hearing aid. It also assessed respondents' perceptions of control and delay for each event. Data analysis using a repeated-measures MANOVA showed that optimistic bias occurred for all four events. Optimistic bias was significantly greater for the two events high in control (skin cancer and accident as the driver) than for those low in control (accident as a passenger and hearing aid). Delay was not related to the magnitude of optimistic bias. These findings have implications for health promotion campaigns and self-protective behaviors.

Complexity theory and organizing form dualities

Purpose – The purpose of this paper is to describe how order-generated rules applied to organizing form dualities can assist in creating the conditions for emergent, self-organized behavior in organizations, thereby offering an operational deployment of complexity theory.

Design/methodology/approach – The paper begins by showing that the concept of dualities is consistent with complexity-thinking. In addition, when applied to organizing forms, dualities represent a practical way of affecting an organization's balance between chaos and order. Thus, when augmented with order-generating rules, organizing form dualities provide an access point for the practical instigation of edge of chaos conditions and the potential for emergence.

Findings – The paper maintains that many attempts to “manage” complexity have been associated with changes to organizing forms, specifically toward new forms of organizing. It is suggested that organizing form dualities provide some management guidance for encouraging the “edge of chaos” conditions advocated in complexity theory, although the details of self-organization cannot be prescribed given the assumptions of non-linearity associated with complexity theory perspectives. Finally, it is proposed that organizing dualities can elucidate the nature and application of order-generating rules in non-linear complex systems.

Practical implications – Dualities offer some guidance toward the practical implementation of complexity theory as they represent an accessible sub-system where the forces for order and chaos – traditional and new forms of organizing respectively – are accessible and subject to manipulation.

Originality/value – The commonalities between dualities and complexity theory are intuitive, but little conceptual work has shown how the former can be employed as a guide to managing organizing forms. Moreover, this approach demonstrates that managers may be able to stimulate “edge of chaos” conditions in a practical way, without making positivistic assumptions about the causality associated with their efforts.

Synthesis and mechanistic insights of macromolecular assemblies from ABA triblock copolymer blends

Macromolecular assembly of block copolymers into numerous nanostructures resembles self-organization of proteins and cellular components found in nature. In order to mimic nature’s assemblies either to cure a disease or construct functional devices, the organization principles underpinning the emergence of complex shapes need to be understood. In the same vein, this study aimed at understanding morphology evolution in a triblock copolymer blend in aqueous solution. An ABA type amphiphilic triblock copolymer (polystyrene-b-polyethylene oxide-b-polystyrene, PS-b-PEO-b-PS) was synthesized at different compositions via atom transfer radical polymerization (ATRP) and self-assembly behavior of a binary mixture in aqueous solution was studied. Block copolymers that form worms and vesicles in its pristine state was shown to form complex morphologies such as fused rings, “jellyfish”, toroid vesicles, large compound vesicles and large lamellae after blending. The tendency of vesicle-forming block copolymer to form bilayers may be responsible for triggering complex morphologies when mixed with a worm or micelle-forming polymer. In other words, the interplay between curvature effects produced by two distinct polymers with different hydrophobic block lengths results in complex morphologies due to chain segregation within the nanostructure.

High-performance multifunctional graphene yarns: toward wearable all-carbon energy storage textiles

The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young's modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m(-1)) and exceptionally high specific surface area (2605 m(2) g(-1) before reduction and 2210 m(2) g(-1) after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of individual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g(-1) at 1 A g(-1)) and rate capability (56 F g(-1) at 100 A g(-1)) while maintaining their strong flexible nature.

Phase behavior, crystallization, and hierarchical nanostructures in self-organized thermoset blends of epoxy resin and amphiphilic poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) triblock copolymers

Nanostructured thermoset blends of bisphenol A-type epoxy resin (ER) and amphiphilic poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers were successfully prepared. Two samples of PEO-PPO-PEO triblock copolymer with different ethylene oxide (EO) contents, denoted as EO30 with 30 wt % EO content and EO80 with 80 wt % EO content, were used to form the self-organized thermoset blends of varying compositions using 4,4'-methylenedianiline (MDA) as curing agent. The phase behavior, crystallization, and morphology were investigated by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), atomic force microscopy (AFM), and small-angle X-ray scattering (SAXS). It was found that macroscopic phase separation took place in the MDA-cured ER/EO30 blends containing 60-80 wt % EO30 triblock copolymer. The MDA-cured ER/EO30 blends with EO30 content up to 50 wt % do not show macroscopic phase separation but exhibit nanostructures on the order of 10-30 nm as revealed by both the TEM and SAXS studies. The AFM study further shows that the ER/EO30 blend at some composition displays structural inhomogeneity at two different nanoscales and is hierarchically nanostructured. The spherical PPO domains with an average size of about 10 nm are uniformly dispersed in the 80/20 ER/EO30 blend; meanwhile, a structural inhomogeneity on the order of 50-200 nm is observed. The ER/EO80 blends are not macroscopically phase-separated over the entire composition range because of the much higher PEO content of the EO80 triblock copolymer. However, the ER/EO80 blends show composition-dependent nanostructures on the order of 10-100 nm. The 80/20 ER/EO80 blend displays hierarchical structures at two different nanoscales, i.e., a bicontinuous microphase structure on the order of about 100 nm and spherical domains of 10-20 nm in diameter uniformly dispersed in both the continuous microphases. The blends with 60 wt % and higher EO80 content are completely volume-filled with spherulites. Bundles of PEO lamellae with spacing of 20-30 nm interwoven with a microphase structure on the order of about 100 nm are revealed by AFM study for the 30/70 ER/EO80 blend.

Pubertal stage and deliberate self-harm in adolescents

Objective: To ascertain the association between pubertal stage and deliberate self-harm.

Method: Cross-sectional survey of 12- to 15-year-olds in 300 secondary schools in the U.S. state of Washington in February-April 2002 and the Australian state of Victoria in June-August 2002. A total of 3,332 students in grades 7 and 9 provided complete data on episodes of deliberate self-harm in the previous 12 months and pubertal stage. Pubertal stage was assessed with the Pubertal Development Scale.

Results: The prevalence of deliberate self-harm was 3.7% with a more than twofold higher rate in females. Late puberty was associated with a more than fourfold higher rate of self-harm (odds ratio 4.6, 95% confidence interval 1.5-14) after adjustment for age and school grade level. In contrast age had a protective association (odds ratio 0.7, confidence interval 0.4-1.0). The sharpest rises in prevalence across puberty were for self-laceration and self-poisoning in females. Higher rates of depressive symptoms, frequent alcohol use, and initiation of sexual activity largely accounted for the association between self-harm and pubertal stage in multivariate models.

Conclusions: Puberty is associated with changes in the form and frequency of self-harm. For adolescents with a gap between puberty and brain development, risk factors such as early sexual activity and substance abuse may be particularly potent.

The effect of school suspensions and arrests on subsequent adolescent antisocial behavior in Australia and the United States

Purpose: To examine the effect of school suspensions and arrests (i.e., being taken into police custody) on subsequent adolescent antisocial behavior such as violence and crime, after controlling for established risk and protective factors in Victoria, Australia and Washington State, United States (U.S.). Methods: This article reports on analyses of two points of data collected 1 year apart within a cross-national longitudinal study of the development of antisocial behavior, substance use, and related behaviors in approximately 4000 students aged 12 to 16 years in Victoria, Australia and Washington State, U.S. Students completed a modified version of the Communities That Care self-report survey of behavior, as well as risk and protective factors across five domains (individual, family, peer, school, and community). Multivariate logistic regression analyses investigate the effect of school suspensions and arrests on subsequent antisocial behavior, holding constant individual, family, peer, school, and community level influences such as being female, student belief in the moral order, emotional control, and attachment to mother. Results: At the first assessment, school suspensions and arrests were more commonly reported in Washington, and school suspensions significantly increased the likelihood of antisocial behavior 12 months later, after holding constant established risk and protective factors (adjusted odds ratio [OR] 1.5, 95% confidence interval [CI] 1.1–2.1, _p < .05). Predictors of antisocial behavior spanned risk and protective factors across five individual and ecological areas of risk. Risk factors in this study were pre-existing antisocial behavior (OR 3.6, CI 2.7–4.7, _p < .001), association with antisocial peers (OR 1.8, CI 1.4–2.4, _p < .001), academic failure (OR 1.3, CI 1.1–1.5, _p < .01), and perceived availability of drugs in the community (OR 1.3, CI 1.1–1.5, _p < .001). Protective factors included being female (OR 0.7, CI 0.5–0.9, _p < .01), student belief in the moral order (OR 0.8, CI 0.6–1.0, p < .05), student emotional control (OR 0.7, CI 0.6–0.8, _p < .001), and attachment to mother (OR 0.8, CI 0.7–1.0, _p < .05). Conclusions:  School suspensions may increase the likelihood of future antisocial behavior. Further research is required to both replicate this finding and establish the mechanisms by which school suspensions exert their effects.

Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways

It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers.