Imaging dielectric relaxation in nanostructured polymers by frequency modulation electrostatic force microscopy

We have developed a method for imaging the temperature-frequency dependence of the dynamics of nanostructured polymer films with spatial resolution. This method provides images with dielectric compositional contrast well decoupled from topography. Using frequency-modulation electrostatic-force-microscopy, we probe the local frequency-dependent (0.1–100 Hz) dielectric response through measurement of the amplitude and phase of the force gradient in response to an oscillating applied electric field. When the phase is imaged at fixed frequency, it reveals the spatial variation in dielectric losses, i.e., the spatial variation in molecular/dipolar dynamics, with 40 nm lateral resolution. This is demonstrated by using as a model system; a phase separated polystyrene/polyvinyl-acetate (PVAc) blend. We show that nanoscale dynamic domains of PVAc are clearly identifiable in phase images as those which light-up in a band of temperature, reflecting the variations in the molecular/dipolar dynamics approaching the glass transition temperature of PVAc

De kost verdienen: de behoefte van voedsters aan ruwvoer

Om na te gaan of voedsters behoefte hebben aan ruwvoer is een kooi met keuzemogelijkheden ontwikkeld volgens het consumer-demand model. Begin dit jaar is men gestart met een eerste ronde, waarin voedsters konden kiezen tussen drie soorten ruwvoer. In dit artikel wordt ingegaan op dit onderzoe

Minder longziekten bij vleesvarkens door niet mengen van varkens

Op bedrijven, waar de vleesvarkens niet worden gemengd of niet worden teruggeplaatst vanuit de ziekenboeg, blijken minder longaandoeningen voor te komen. Dit komt bij een onderzoek naar de oorzaken van longziekten op 16 biologische varkensbedrijven naar vore

Virtual reality based cognitive behavioral therapy for paranoia:Effects on mental states and the dynamics among them

Background: Negative affective processes may contribute to maintenance of paranoia in patients with psychosis, and vice versa. Successful treatment may break these pathological symptom networks. This study examined whether treatment with virtual reality based cognitive behavioral therapy (VR-CBT) for paranoia influences momentary affective states, and whether VR-CBT changes the adverse interplay between affective states and paranoia. Methods: Patients with a psychotic disorder (n = 91) were randomized to 16-session VR-CBT or treatment as usual (TAU). With the experience sampling method (structured diary technique) mental states were assessed for 6–10 days at baseline, posttreatment and 6-month follow-up. Multilevel analysis were performed to establish treatment effects and time-lagged associations between mental states, that were visualized with networks of mental states. Results: Average levels of paranoia (feeling suspicious [b = −032., p = .04], disliked [b = −49., p < .01] and hurt [b = −0.52, p < .01]) and negative affect (anxious [b = −0.37, p = .01], down [b = −0.33, p = .04] and insecure [b = −0.17, p = .03) improved more after VR-CBT than TAU, but positive affect did not. Baseline mental state networks had few significant connections, with most stable connections being autocorrelations of mental states. The interplay between affective states and paranoia did not change in response to treatment. A trend reduction in average intranode connections (autocorrelations) was found after VR-CBT (b = −0.07, p = .08), indicating that mental states reinforce themselves less after treatment. Conclusions: VR-CBT reduced paranoid symptoms and lowered levels of negative affect in daily life, but did not affect the extent to which mental states influenced each other. Findings do suggest that as a result of treatment mental states regain flexibility

Effect of macrophage depletion on immune effector mechanisms during corneal allograft rejection in rats

PURPOSE. In rats, corneal allograft rejection is delayed for at least 100 days by clodronate liposomes. These liposomes selectively deplete macrophages. To investigate the immunologic basis for absence of graft rejection in treated rats, the effect of these liposomes on the generation of cytotoxic T lymphocytes (CTLs) and antibody production after orthotopic corneal allotransplantation was determined. METHODS. Transplantations of corneal buttons from PVG rats were performed in AO rats. After surgery, one group received clodronate liposomes subconjunctivally at five time points, and the other group remained untreated. On postoperative day (POD) 3, 7, 12, or 17, rats were killed, the presence of CTLs was investigated at three different anatomic locations, and antibodies against donor antigens were tested. RESULTS. NO significant differences were found between the groups tested 3 and 7 days after surgery. But on POD 12 (the time of onset of rejection in the untreated group) and on POD 17, the CTL activities detected in the submandibular lymph nodes (P less than or equal to 0.008) and the spleen (P less than or equal to 0.009) were significantly less in the treated groups compared with the untreated groups. in the untreated groups complement-independent antibodies were present only on POD 17, whereas no antibodies were found in the treated rats. CONCLUSIONS. Local treatment with clodronate liposomes was shown to downregulate local and systemic CTL responses and to prevent the generation of antibodies. Local depletion of macrophages in the initiation phase of the immune response appears to lead to a less vigorous attack on the grafted tissue and therefore to promote graft survival

Etiological spectrum and treatment outcome of Obstructive jaundice at a University teaching Hospital in northwestern Tanzania: A diagnostic and therapeutic challenges

Obstructive jaundice poses diagnostic and therapeutic challenges to general surgeons practicing in resource-limited countries. This study was undertaken to highlight the etiological spectrum, treatment outcome of obstructive jaundice in our setting and to identify prognostic factors for morbidity and mortality. This was a descriptive prospective study which was conducted at Bugando Medical Centre between July 2006 and June 2010. All patients with a clinical diagnosis of obstructive jaundice were, after informed consent for the study, consecutively enrolled into the study. Data were collected using a pre-tested structured questionnaire and analyzed using SPSS computer software version 11.5. A total of 116 patients were studied. Females outnumbered males by a ratio of 1.3:1. Patients with malignant obstructive jaundice were older than those of benign type. Ca head of pancreas was the commonest malignant cause of jaundice where as choledocholithiasis was the commonest benign cause. Abdominal ultrasound was the only diagnostic imaging done in all patients and revealed dilated intra and extra-hepatic ducts, common bile stones and abdominal masses in 56.2%, 78.9%, 58.1% and 72.4% of the cases respectively. A total of 110 (94.8%) patients underwent surgical treatment and the remaining 6 (5.2%) patients were unfit for surgery. The complication rate was 22.4% mainly surgical site infections. The mean hospital stay and mortality rate were 14.54 days and 15.5% respectively. A low haematocrit and presence of postoperative sepsis were the main predictors of the hospital stay (P < 0.001), whereas age > 60 years, prolonged duration of jaundice, malignant causes and presence of postoperative complications mainly sepsis significantly predicted mortality (P < 0.001). Obstructive jaundice in our setting is more prevalent in females and the cause is mostly malignant. The result of this study suggests that early diagnosis and treatment plays an important role in the prognosis of patients with obstructive jaundice

Omnivorousness in sport: The importance of social capital and networks

There has been for some time a significant and growing body of research around the relationship between sport and social capital. Similarly, within sociology there has been a corpus of work that has acknowledged the emergence of the omnivore–univore relationship. Surprisingly, relatively few studies examining sport and social capital have taken the omnivore–univore framework as a basis for understanding the relationship between sport and social capital. This gap in the sociology of sport literature and knowledge is rectified by this study that takes not Putnam, Coleman or Bourdieu, but Lin’s social network approach to social capital. The implications of this article are that researchers investigating sport and social capital need to understand more about how social networks and places for sport work to create social capital and, in particular, influence participating in sporting activities. The results indicate that social networks both facilitate and constrain sports participation; whilst family and friendship networks are central in active lifestyles, those who are less active have limited networks