Random, blocky and alternating ordering in supramolecular polymers of chemically bidisperse monomers

As a first step to understanding the role of molecular or chemical polydispersity in self-assembly, we put forward a coarse-grained model that describes the spontaneous formation of quasi-linear polymers in solutions containing two self-assembling species. Our theoretical framework is based on a two-component self-assembled Ising model in which the bidispersity is parameterized in terms of the strengths of the binding free energies that depend on the monomer species involved in the pairing interaction. Depending upon the relative values of the binding free energies involved, different morphologies of assemblies that include both components are formed, exhibiting paramagnetic-, ferromagnetic- or anti ferromagnetic-like order,i.e., random, blocky or alternating ordering of the two components in the assemblies. Analyzing the model for the case of ferromagnetic ordering, which is of most practical interest, we find that the transition from conditions of minimal assembly to those characterized by strong polymerization can be described by a critical concentration that depends on the concentration ratio of the two species. Interestingly, the distribution of monomers in the assemblies is different from that in the original distribution, i.e., the ratio of the concentrations of the two components put into the system. The monomers with a smaller binding free energy are more abundant in short assemblies and monomers with a larger binding affinity are more abundant in longer assemblies. Under certain conditions the two components congregate into separate supramolecular polymeric species and in that sense phase separate. We find strong deviations from the expected growth law for supramolecular polymers even for modest amounts of a second component, provided it is chemically sufficiently distinct from the main one.Comment: Submitted to Macromolecules, 6 figures. arXiv admin note: substantial text overlap with arXiv:1111.176

Non-suicidal self-injury (Nssi) in adolescent inpatients: assessing personality features and attitude toward death

<p>Abstract</p> <p>Background</p> <p>Non-suicidal self-injury (NSSI) is a common concern among hospitalized adolescents, and can have significant implications for short and long-term prognosis. Little research has been devoted on how personality features in severely ill adolescents interact with NSSI and "attitude toward life and death" as a dimension of suicidality. Developing more specific assessment methodologies for adolescents who engage in self-harm without suicidal intent is relevant given the recent proposal of a non-suicidal self-injury (NSSI) disorder and may be useful in predicting risk in psychiatrically impaired subjects.</p> <p>Methods</p> <p>Consecutively hospitalized adolescents in a psychiatric unit (N = 52; 71% females; age 12-19 years), reporting at least one recent episode of self-harm according to the <it>Deliberate Self-harm Inventory</it>, were administered the <it>Structured Clinical Interview for DSM Mental Disorders and Personality Disorders (SCID I and II)</it>, the <it>Children's Depression Inventory </it>and the <it>Multi-Attitude Suicide Tendency Scale (MAST)</it>.</p> <p>Results</p> <p>Mean age onset of NSSI in the sample was 12.3 years. All patients showed "repetitive" NSSI (high frequency of self-harm), covering different modalities. Results revealed that 63.5% of adolescents met criteria for Borderline Personality Disorder (BPD) and that the rest of the sample also met criteria for personality disorders with dysregulated traits. History of suicide attempts was present in 46.1% of cases. Elevated depressive traits were found in 53.8%. Results show a statistically significant negative correlation between the score on the "Attraction to Life" subscale of the MAST and the <it>frequency </it>and <it>diversification </it>of self-harming behaviors.</p> <p>Conclusions</p> <p>Most adolescent inpatients with NSSI met criteria for emotionally dysregulated personality disorders, and showed a reduced "attraction to life" disposition and significant depressive symptoms. This peculiar psychopathological configuration must be addressed in the treatment of adolescent inpatients engaging in NSSI and taken into account for the prevention of suicidal behavior in self-injuring adolescents who do not exhibit an explicit intent to die.</p

Working conditions, self-perceived stress, anxiety, depression and quality of life: A structural equation modelling approach

<p>Abstract</p> <p>Background</p> <p>The relationships between working conditions [job demand, job control and social support]; stress, anxiety, and depression; and perceived quality of life factors [physical health, psychological wellbeing, social relationships and environmental conditions] were assessed using a sample of 698 male automotive assembly workers in Malaysia.</p> <p>Methods</p> <p>The validated Malay version of the Job Content Questionnaire (JCQ), Depression Anxiety Stress Scales (DASS) and the World Health Organization Quality of Life-Brief (WHOQOL-BREF) were used. A structural equation modelling (SEM) analysis was applied to test the structural relationships of the model using AMOS version 6.0, with the maximum likelihood ratio as the method of estimation.</p> <p>Results</p> <p>The results of the SEM supported the hypothesized structural model (<it>χ</it>²= 22.801, <it>df </it>= 19, <it>p </it>= 0.246). The final model shows that social support (JCQ) was directly related to all 4 factors of the WHOQOL-BREF and inversely related to depression and stress (DASS). Job demand (JCQ) was directly related to stress (DASS) and inversely related to the environmental conditions (WHOQOL-BREF). Job control (JCQ) was directly related to social relationships (WHOQOL-BREF). Stress (DASS) was directly related to anxiety and depression (DASS) and inversely related to physical health, environment conditions and social relationships (WHOQOL-BREF). Anxiety (DASS) was directly related to depression (DASS) and inversely related to physical health (WHOQOL-BREF). Depression (DASS) was inversely related to the psychological wellbeing (WHOQOL-BREF). Finally, stress, anxiety and depression (DASS) mediate the relationships between job demand and social support (JCQ) to the 4 factors of WHOQOL-BREF.</p> <p>Conclusion</p> <p>These findings suggest that higher social support increases the self-reported quality of life of these workers. Higher job control increases the social relationships, whilst higher job demand increases the self-perceived stress and decreases the self-perceived quality of life related to environmental factors. The mediating role of depression, anxiety and stress on the relationship between working conditions and perceived quality of life in automotive workers should be taken into account in managing stress amongst these workers.</p

Risk factors predict post-traumatic stress disorder differently in men and women

<p>Abstract</p> <p>Background</p> <p>About twice as many women as men develop post-traumatic stress disorder (PTSD), even though men as a group are exposed to more traumatic events. Exposure to different trauma types does not sufficiently explain why women are more vulnerable.</p> <p>Methods</p> <p>The present work examines the effect of age, previous trauma, negative affectivity (NA), anxiety, depression, persistent dissociation, and social support on PTSD separately in men and women. Subjects were exposed to either a series of explosions in a firework factory near a residential area or to a high school stabbing incident.</p> <p>Results</p> <p>Some gender differences were found in the predictive power of well known risk factors for PTSD. Anxiety predicted PTSD in men, but not in women, whereas the opposite was found for depression. Dissociation was a better predictor for PTSD in women than in men in the explosion sample but not in the stabbing sample. Initially, NA predicted PTSD better in women than men in the explosion sample, but when compared only to other significant risk factors, it significantly predicted PTSD for both men and women in both studies. Previous traumatic events and age did not significantly predict PTSD in either gender.</p> <p>Conclusion</p> <p>Gender differences in the predictive value of social support on PTSD appear to be very complex, and no clear conclusions can be made based on the two studies included in this article.</p

Universality of interpersonal psychotherapy (IPT) problem areas in Thai depressed patients

<p>Abstract</p> <p>Background</p> <p>Many studies have shown the efficacy of interpersonal psychotherapy (IPT) on depression; however, there are limited studies concerning the universality of the IPT problem areas in different countries. This study identifies whether the interpersonal problem areas defined in the IPT manual are endorsed by Thai depressed patients.</p> <p>Methods</p> <p>The Thai Hamilton Rating Scale for Depression (Thai HRSD) and Thai Interpersonal Questionnaire were used to assess 90 depressed and 90 non-depressed subjects in King Chulalongkorn Memorial Hospital, during July 2007 - January 2008. The association between interpersonal problem areas/sociodemographic variables and depressive disorder were analyzed by chi-square test. A multivariable analysis was performed by using logistic regression to identify the remaining factors associated with depressive disorder.</p> <p>Results</p> <p>Most of the subjects were young to middle-aged females living in Bangkok and the Central Provinces. All four interpersonal problem areas (grief, interpersonal role disputes, role transitions, and interpersonal deficits) were increased in the depressed subjects as compared to the non-depressed subjects, as were the sociodemographic variables (low education, unemployment, low income, and having a physical illness). Logistic regression showed that all interpersonal problem areas still remained problems associated with depression (grief: adjusted OR = 6.01, 95%CI = 1.93 - 18.69, p < 0.01; interpersonal role disputes: adjusted OR = 6.01, 95%CI = 2.18 - 16.52, p < 0.01; role transitions: adjusted OR = 26.30, 95%CI = 7.84 - 88.25, p < 0.01; and interpersonal deficits: adjusted OR = 2.92, 95%CI = 1.12 - 7.60, p < 0.05).</p> <p>Conclusion</p> <p>All four interpersonal problem areas were applicable to Thai depressed patients.</p

High Cooperativity of the SV40 Major Capsid Protein VP1 in Virus Assembly

SV40 is a small, non enveloped DNA virus with an icosahedral capsid of 45 nm. The outer shell is composed of pentamers of the major capsid protein, VP1, linked via their flexible carboxy-terminal arms. Its morphogenesis occurs by assembly of capsomers around the viral minichromosome. However the steps leading to the formation of mature virus are poorly understood. Intermediates of the assembly reaction could not be isolated from cells infected with wt SV40. Here we have used recombinant VP1 produced in insect cells for in vitro assembly studies around supercoiled heterologous plasmid DNA carrying a reporter gene. This strategy yields infective nanoparticles, affording a simple quantitative transduction assay. We show that VP1 assembles under physiological conditions into uniform nanoparticles of the same shape, size and CsCl density as the wild type virus. The stoichiometry is one DNA molecule per capsid. VP1 deleted in the C-arm, which is unable to assemble but can bind DNA, was inactive indicating genuine assembly rather than non-specific DNA-binding. The reaction requires host enzymatic activities, consistent with the participation of chaperones, as recently shown. Our results demonstrate dramatic cooperativity of VP1, with a Hill coefficient of ∼6. These findings suggest that assembly may be a concerted reaction. We propose that concerted assembly is facilitated by simultaneous binding of multiple capsomers to a single DNA molecule, as we have recently reported, thus increasing their local concentration. Emerging principles of SV40 assembly may help understanding assembly of other complex systems. In addition, the SV40-based nanoparticles described here are potential gene therapy vectors that combine efficient gene delivery with safety and flexibility

Recruiting participants for interventions to prevent the onset of depressive disorders: Possibile ways to increase participation rates

Background: Although indicated prevention of depression is available for about 80% of the Dutch population at little or no cost, only a small proportion of those with subthreshold depression make use of these services. Methods: A narrative review is conducted of the Dutch preventive services in mental health care, also addressing the problem of low participation rates. We describe possible causes of these low participation rates, which may be related to the participants themselves, the service system, and the communication to the public, and we put forward possible solutions to this problem. Results: There are three main groups of reasons why the participation rates are low: reasons within the participants (e.g., not considering themselves as being at risk; thinking the interventions are not effective; or being unwilling to participate because of the stigma associated with depression); reasons within the health care system; and reasons associated with the communication about the preventive services. Possible solutions to increasing the participation rate include organizing mass media campaigns, developing internet-based preventive interventions, adapting preventive interventions to the needs of specific subpopulations, positioning the services in primary care, integrating the interventions in community-wide interventions, and systematically screening high-risk groups for potential participants. Discussion: Prevention could play an important role in public mental health in reducing the enormous burden of depression. However, before this can be realized more research is needed to explore why participation rates are low and how these rates can be improved

Exploring recruitment, willingness to participate, and retention of low-SES women in stress and depression prevention

Contains fulltext : 90907.pdf (publisher's version ) (Open Access)Background Recruitment, willingness to participate, and retention in interventions are indispensable for successful prevention. This study investigated the effectiveness of different strategies for recruiting and retaining low-SES women in depression prevention, and explored which sociodemographic characteristics and risk status factors within this specific target group are associated with successful recruitment and retention. Methods The process of recruitment, willingness to participate, and retention was structurally mapped and explored. Differences between women who dropped out and those who adhered to the subsequent stages of the recruitment and retention process were investigated. The potential of several referral strategies was also studied, with specific attention paid to the use of GP databases. Results As part of the recruitment process, 12.1% of the target population completed a telephone screening. The most successful referral strategy was the use of patient databases from GPs working in disadvantaged neighborhoods. Older age and more severe complaints were particularly associated with greater willingness to participate and with retention. Conclusions Low-SES women can be recruited and retained in public health interventions through tailored strategies. The integration of mental health screening within primary care might help to embed preventive interventions in low-SES communities.8 p

Direct Binding of a Hepatitis C Virus Inhibitor to the Viral Capsid Protein

Over 130 million people are infected chronically with hepatitis C virus (HCV), which, together with HBV, is the leading cause of liver disease. Novel small molecule inhibitors of Hepatitis C virus (HCV) are needed to complement or replace current treatments based on pegylated interferon and ribavirin, which are only partially successful and plagued with side-effects. Assembly of the virion is initiated by the oligomerization of core, the capsid protein, followed by the interaction with NS5A and other HCV proteins. By screening for inhibitors of core dimerization, we previously discovered peptides and drug-like compounds that disrupt interactions between core and other HCV proteins, NS3 and NS5A, and block HCV production. Here we report that a biotinylated derivative of SL209, a prototype small molecule inhibitor of core dimerization (IC50 of 2.80 µM) that inhibits HCV production with an EC50 of 3.20 µM, is capable of penetrating HCV-infected cells and tracking with core. Interaction between the inhibitors, core and other viral proteins was demonstrated by SL209–mediated affinity-isolation of HCV proteins from lysates of infected cells, or of the corresponding recombinant HCV proteins. SL209-like inhibitors of HCV core may form the basis of novel treatments of Hepatitis C in combination with other target-specific HCV drugs such as inhibitors of the NS3 protease, the NS5B polymerase, or the NS5A regulatory protein. More generally, our work supports the hypothesis that inhibitors of viral capsid formation might constitute a new class of potent antiviral agents, as was recently also shown for HIV capsid inhibitors

Intimate partner violence among pregnant women in Rwanda

<p>Abstract</p> <p>Background</p> <p>Intimate partner violence (IPV), defined as actual or threatened physical, sexual, psychological, and emotional abuse by current or former partners is a global public health concern. The prevalence and determinants of intimate partner violence (IPV) against pregnant women has not been described in Rwanda. A study was conducted to identify variables associated with IPV among Rwandan pregnant women.</p> <p>Methods</p> <p>A convenient sample of 600 pregnant women attending antenatal clinics were administered a questionnaire which included items on demographics, HIV status, IPV, and alcohol use by the male partner. Mean age and proportions of IPV in different groups were assessed. Odds of IPV were estimated using logistic regression analysis.</p> <p>Results</p> <p>Of the 600 respondents, 35.1% reported IPV in the last 12 months. HIV+ pregnant women had higher rates of all forms of IVP violence than HIV- pregnant women: pulling hair (44.3% vs. 20.3%), slapping (32.0% vs. 15.3%), kicking with fists (36.3% vs. 19.7%), throwing to the ground and kicking with feet (23.3% vs. 12.7%), and burning with hot liquid (4.1% vs. 3.5%). HIV positive participants were more than twice likely to report physical IPV than those who were HIV negative (OR = 2.38; 95% CI [1.59, 3.57]). Other factors positively associated with physical IPV included sexual abuse before the age of 14 years (OR = 2.69; 95% CI [1.69, 4.29]), having an alcohol drinking male partner (OR = 4.10; 95% CI [2.48, 6.77] for occasional drinkers and OR = 3.37; 95% CI [2.05, 5.54] for heavy drinkers), and having a male partner with other sexual partners (OR = 1.53; 95% CI [1.15, 2.20]. Education was negatively associated with lifetime IPV.</p> <p>Conclusion</p> <p>We have reported on prevalence of IPV violence among pregnant women attending antenatal care in Rwanda, Central Africa. We advocate that screening for IPV be an integral part of HIV and AIDS care, as well as routine antenatal care. Services for battered women should also be made available.</p