A relationship between structural and electronic order-disorder effects and optical properties in crystalline TiO2 nanomaterials

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Randomized, Naturalistic, Parallel-Group Study for the Long-Term Treatment of Panic Disorder With Clonazepam or Paroxetine

This long-term extension of an 8-week randomized, naturalistic study in patients with panic disorder with or without agoraphobia compared the efficacy and safety of clonazepam (n = 47) and paroxetine (n = 37) over a 3-year total treatment duration. Target doses for all patients were 2 mg/d clonazepam and 40 mg/d paroxetine (both taken at bedtime). This study reports data from the long-term period (34 months), following the initial 8-week treatment phase. Thus, total treatment duration was 36 months. Patients with a good primary outcome during acute treatment continued monotherapy with clonazepam or paroxetine, but patients with partial primary treatment success were switched to the combination therapy. At initiation of the long-term study, the mean doses of clonazepam and paroxetine were 1.9 (SD, 0.30) and 38.4 (SD, 3.74) mg/d, respectively. These doses were maintained until month 36 (clonazepam 1.9 [ SD, 0.29] mg/d and paroxetine 38.2 [SD, 3.87] mg/d). Long-term treatment with clonazepam led to a small but significantly better Clinical Global Impression (CGI)-Improvement rating than treatment with paroxetine (mean difference: CGI-Severity scale -3.48 vs -3.24, respectively, P = 0.02; CGI-Improvement scale 1.06 vs 1.11, respectively, P = 0.04). Both treatments similarly reduced the number of panic attacks and severity of anxiety. Patients treated with clonazepam had significantly fewer adverse events than those treated with paroxetine (28.9% vs 70.6%, P < 0.001). The efficacy of clonazepam and paroxetine for the treatment of panic disorder was maintained over the long-term course. There was a significant advantage with clonazepam over paroxetine with respect to the frequency and nature of adverse events.

Rounding of a first-order quantum phase transition to a strong-coupling critical point

We investigate the effects of quenched disorder on first-order quantum phase transitions on the example of the N-color quantum Ashkin-Teller model. By means of a strong-disorder renormalization group, we demonstrate that quenched disorder rounds the first-order quantum phase transition to a continuous one for both weak and strong coupling between the colors. In the strong-coupling case, we find a distinct type of infinite-randomness critical point characterized by additional internal degrees of freedom. We investigate its critical properties in detail and find stronger thermodynamic singularities than in the random transverse field Ising chain. We also discuss the implications for higher spatial dimensions as well as unusual aspects of our renormalization-group scheme. DOI: 10.1103/PhysRevB.86.214204

Biaxial nematic phase in the Maier-Saupe model for a mixture of discs and cylinders

We analyze the global phase diagram of a Maier-Saupe lattice model with the inclusion of shape-disordered degrees of freedom to mimic a mixture of oblate and prolate molecules (discs and cylinders). In the neighborhood of a Landau multicritical point, solutions of the statistical problem can be written as a Landau-de Gennes expansion for the free energy. If the shape-disordered degrees of freedom are quenched, we confirm the existence of a biaxial nematic structure. If orientational and disorder degrees of freedom are allowed to thermalize, this biaxial solution becomes thermodynamically unstable. Also, we use a two-temperature formalism to mimic the presence of two distinct relaxation times, and show that a slight departure from complete thermalization is enough to stabilize a biaxial nematic phase.

Eingefrorene Unordnung und Magnetismus in TiFe_1tn2-Laves-Phase-Dünnschichten

In der vorliegenden Arbeit wird die binäre intermetallische Verbindung TixFe1-x im C14 Laves-Phase Stabilitätsbereich anhand von dünnen Schichten untersucht. TiFe2 weist zwei energetisch nahezu entartete magnetische Grundzustände auf. Dies führt zu einer starken Korrelation von strukturellen und magnetischen Eigenschaften, die im Rahmen dieser Arbeit untersucht wurden. Es wurden daher epitaktische Schichten mit variabler Zusammensetzung im C14 Stabilitätsbereich auf Al2O3 (001)-orientierten Substraten mittels Molekularstrahlepitaxie präpariert und strukturell charakterisiert. Die temperatur- und magnetfeldabhängigen magnetischen Eigenschaften dieser Proben wurden mittels DC-SQUID Magnetisierungsmessungen bestimmt. Es zeigte sich eine magnetische Phasenseparation von Antiferromagnetismus und Ferromagnetismus in Abhängigkeit von der Zusammensetzung. Aus den charakteristischen Ordnungstemperaturen konnte ein magnetisches Phasendiagramm für dünne Schichten und niedrige Aligning-Felder erstellt werden. Ein Phasendiagramm für Volumenproben bei hohem Magnetfeld unterscheidet sich von diesem im Wesentlichen durch den Einfluß von Fe-Segregation in den Volumenproben, welche bei der epitaktischen Präparation nicht auftritt. Anhand von Monte-Carlo Verfahren, denen ein „quenched random disorder“ Modell zugrunde lag, wurde das Verhalten der Dünnschichtproben simuliert und daraus ein magnetisches Phasendiagramm abgeleitet. Das simulierte und experimentelle Phasendiagramm stimmt in den wesentlichen Punkten überein. Die Unterschiede sind durch die speziellen Wachstumseigenschaften von TiFe2 erklärbar. Als Ergebnis kann die magnetische Phasenseparation in diesem System als Auswirkung einer Symmetriebrechung durch Substitution in der Einheitszelle beschrieben werden.

Nondermatomal somatosensory deficits in patients with chronic pain disorder: clinical findings and hypometabolic pattern in FDG-PET

Patients with chronic pain disorders often show somatosensory disturbances that are considered to be functional. This paper aims at a more precise clinical description and at a documentation of functional neuroimaging correlates of this phenomenon. We examined 30 consecutive patients with unilaterally accentuated chronic pain not explained by persistent peripheral tissue damage and ipsilateral somatosensory disturbances including upper and lower extremities and trunk. The patients were assessed clinically and with conventional brain CT or MRI scan. In the last 11 patients functional neuroimaging was carried out (18-fluordeoxyglucose positron emission tomography=FDG-PET). Depressive symptoms were assessed with the Hamilton depression scale (HAMD-17) and pain intensity was rated with a visual analogue scale for pain (VAS). All patients suffered from mild to moderate depressive symptoms. All patients had experienced a prolonged antecedent phase of severe emotional distress; most of them remembered a "trigger episode of somatic pain" on the affected side. Somatosensory deficits were a replicable hyposensitivity to touch and heat perception of nondermatomal distribution. Conventional imaging procedures (brain CT or MRI scans) showed no structural changes. However, in 11 patients functional imaging with FDG-PET showed a significant hypometabolic pattern of changes in cortical and subcortical areas, mainly in the post-central gyrus, posterior insula, putamen, and anterior cingulate cortex. In summary, pain-related nondermatomal somatosensory deficits (NDSDs) are a phenomenon involving biological as well as psychosocial factors with replicable neuroperceptive clinical findings and a complex neurodysfunctional pattern in the FDG-PET.

Does a Pre-Treatment Diagnostic Interview Affect the Outcome of Internet-Based Self-Help for Social Anxiety Disorder? A Randomized Controlled Trial

BACKGROUND: Numerous studies suggest that Internet-based self-help treatments are effective in treating anxiety disorders. Trials evaluating such interventions differ in their screening procedures and in the amount of clinician contact in the diagnostic assessment phase. The present study evaluates the impact of a pre-treatment diagnostic interview on the outcome of an Internet-based treatment for Social Anxiety Disorder (SAD). METHOD: One hundred and nine participants seeking treatment for SAD were randomized to either an interview-group (IG, N = 53) or to a non-interview group (NIG, N = 56). All participants took part in the same 10-week cognitive-behavioural unguided self-help programme. Before receiving access to the programme, participants of the IG underwent a structured diagnostic interview. Participants of the NIG started directly with the programme. RESULTS: Participants in both groups showed significant and substantial improvement on social anxiety measures from pre- to post-assessment (d IG = 1.30-1.63; d NIG = 1.00-1.28) and from pre- to 4-month follow-up assessment (d IG = 1.38-1.87; d NIG = 1.10-1.21). Significant between-groups effects in favour of the IG were found on secondary outcome measures of depression and general distress (d = 0.18-0.42). CONCLUSIONS: These findings suggest that Internet-based self-help is effective in treating SAD, whether or not a diagnostic interview is involved. However, the pre-treatment interview seems to facilitate change on secondary outcomes such as depression and general distress.

Effects of Motive-Oriented Therapeutic Relationship in a Ten-Session General Psychiatric Treatment of Borderline Personality Disorder: A Randomized Controlled Trial

Background: Motive-oriented therapeutic relationship (MOTR) was postulated to be a particularly helpful therapeutic ingredient in the early treatment phase of patients with personality disorders, in particular with borderline personality disorder (BPD). The present randomized controlled study using an add-on design is the first study to test this assumption in a 10-session general psychiatric treatment with patients presenting with BPD on symptom reduction and therapeutic alliance. Methods: A total of 85 patients were randomized. They were either allocated to a manual-based short variant of the general psychiatric management (GPM) treatment (in 10 sessions) or to the same treatment where MOTR was deliberately added to the treatment. Treatment attrition and integrity analyses yielded satisfactory results. Results: The results of the intent-to-treat analyses suggested a global efficacy of MOTR, in the sense of an additional reduction of general problems, i.e. symptoms, interpersonal and social problems (F 1, 73 = 7.25, p < 0.05). However, they also showed that MOTR did not yield an additional reduction of specific borderline symptoms. It was also shown that a stronger therapeutic alliance, as assessed by the therapist, developed in MOTR treatments compared to GPM (Z 55 = 0.99, p < 0.04). Conclusions: These results suggest that adding MOTR to psychiatric and psychotherapeutic treatments of BPD is promising. Moreover, the findings shed additional light on the perspective of shortening treatments for patients presenting with BPD.

Emotional processing in a ten-session general psychiatric treatment for borderline personality disorder: a case study

This study examines the effects of a borderline-specific treatment, called general psychiatric management, on emotional change, outcome and therapeutic alliance of an outpatient presenting with borderline personality disorder. Based on the sequential model of emotional processing, emotional states were assessed in a 10-session setting. The case showed an increase in expressions of distress and no change in therapeutic alliance and tended towards general deterioration. Results suggest emotional processing may play a lesser role in general psychiatric management in early phase treatment than previously hypothezised.

Absolute polarity determination of teeth cementum by phase sensitive second harmonic generation microscopy

The absolute sign of local polarity in relation to the biological growth direction has been investigated for teeth cementum using phase sensitive second harmonic generation microscopy (PS-SHGM) and a crystal of 2-cyclooctylamino-5-nitropyridine (COANP) as a nonlinear optic (NLO) reference material. A second harmonic generation (SHG) response was found in two directions of cementum: radial (acellular extrinsic fibers that are oriented more or less perpendicular to the root surface) and circumferential (cellular intrinsic fibers that are oriented more or less parallel to the surface). A mono-polar state was demonstrated for acellular extrinsic cementum. However, along the different parts of cementum in circumferential direction, two corresponding domains were observed featuring an opposite sign of polarity indicative for a bi-polar microscopic state of cellular intrinsic cementum. The phase information showed that the orientation of radial collagen fibrils of cementum is regularly organized with the donor (D) groups pointing to the surface. Circumferential collagen molecules feature orientational disorder and are oriented up and down in random manner showing acceptor or donor groups at the surface of cementum. Considering that the cementum continues to grow in thickness throughout life, we can conclude that the cementum is growing circumferentially in two opposite directions and radially in one direction. A Markov chain type model for polarity formation in the direction of growth predicts D-groups preferably appearing at the fiber front.

Exercise and Mood: Exploring the Role of Exercise in Regulating Stress Reactivity in Bipolar Disorder

Bipolar Disorder (BD) is a recurrent and debilitating psychological disorder characterized by a chronic dysregulation of mood with fluctuations between extremely low (e.g., depression) and extremely elevated mood states (e.g., mania), and ranks as the 6th leading cause of disability in the world. Although research has consistently shown that exercise may have antidepressant and stress-attenuating benefits in other psychiatric illnesses (e.g., depression, anxiety), these benefits have not been directly investigated for BD. The current study represents the first known investigation to examine this relationship. Single-participant designs, with crossover and interaction treatment components (i.e., A/B/A/B/A, A/C/A/C/A, A/B/A/C/A, or A/C/A/B/A) were utilized to investigate the impact of participation in a prescribed regimen of exercise (EP) versus standard behavioral activation (SBA; i.e., non-exercise activity) has on stress perception and reactivity, and mood stability in a sample of individuals with BD. Individuals completed four total weeks of treatment, and psychophysiological measures of reactivity were recorded during a laboratory stress task (i.e., backward counting task) prior to and following each two-week intervention phase. No appreciable differences were found between levels of exercise participation between treatment groups. Interestingly, symptoms of depressed mood (BDI-II scores) decreased at similar rates following 4 weeks of treatment for all participants. BDI-II decreases were found to be most correlated with elective exercise participation, although this relationship was not significant. Regarding stress reactivity, elective participation in mild to moderate intensity exercise was found to reduce an individual’s perception of stress reactivity to an acute stressor, while participation in a prescribed program of exercise was more effective in reducing physiological response to the same task. Utilizing multiple forms of behavioral activation simultaneously was found to be most effective in decreasing perception of stress reactivity, and may also result in a positive change in the use of adaptive versus maladaptive coping strategies. Participation in a 4-week program of exercise appeared to provide the most benefit, consistent with exercise habituation theories. Overall, current findings provide preliminary support for the prophylactic benefits of including a prescribed and monitored program of exercise as an adjunct treatment for individuals with BD. Larger scale research is needed to more clearly determine the impact of exercise on stress reactivity and mood episode relapse in individuals with BD.

Separation and fractionation of order and disorder in highly polydisperse systems

We study a polydisperse soft-spheres model for colloids by means of microcanonical Monte Carlo simulations. We consider a polydispersity as high as 24%. Although solidification occurs, neither a crystal nor an amorphous state are thermodynamically stable. A finite size scaling analysis reveals that in the thermodynamic limit: a the fluid-solid transition is rather a crystal-amorphous phase-separation, b such phase-separation is preceded by the dynamic glass transition, and c small and big particles arrange themselves in the two phases according to a complex pattern not predicted by any fractionation scenario.

First Order Phase Transition in a 3D disordered system

We present a detailed numerical study on the effects of adding quenched impurities to a three dimensional system which in the pure case undergoes a strong first order phase transition (specifically, the ferromagnetic/paramagnetic transition of the site-diluted four states Potts model). We can state that the transition remains first-order in the presence of quenched disorder (a small amount of it) but it turns out to be second order as more impurities are added. A tricritical point, which is studied by means of Finite-Size Scaling, separates the first-order and second-order parts of the critical line. The results were made possible by a new definition of the disorder average that avoids the diverging-variance probability distributions that arise using the standard methodology. We also made use of a recently proposed microcanonical Monte Carlo method in which entropy, instead of free energy, is the basic quantity.

Looking beyond the negatives: A time period analysis of positive cognitions, negative cognitions, and working alliance in cognitive-behavior therapy for panic disorder

Time period analysis was used in an international sample of clients ( N = 106) to demonstrate that cognitive - behavioral therapy (CBT) for panic disorder is associated with specific changes in both negative and positive cognitions during the treatment period. In the first 6 weeks of the treatment phase, working alliance failed to predict changes in panic severity, whereas changes in panic self-efficacy and catastrophic misinterpretation of bodily sensations predicted rapid symptom relief. In the last 6 weeks of treatment, higher doses of CBT were associated with further changes in positive and negative cognitions. The findings can be interpreted as suggesting that the role of the working alliance in CBT for panic disorder is to facilitate cognitive change.

Phase transitions and memory effects in the dynamics of Boolean networks

The generating functional method is employed to investigate the synchronous dynamics of Boolean networks, providing an exact result for the system dynamics via a set of macroscopic order parameters. The topology of the networks studied and its constituent Boolean functions represent the system's quenched disorder and are sampled from a given distribution. The framework accommodates a variety of topologies and Boolean function distributions and can be used to study both the noisy and noiseless regimes; it enables one to calculate correlation functions at different times that are inaccessible via commonly used approximations. It is also used to determine conditions for the annealed approximation to be valid, explore phases of the system under different levels of noise and obtain results for models with strong memory effects, where existing approximations break down. Links between Boolean networks and general Boolean formulas are identified and results common to both system types are highlighted. © 2012 Copyright Taylor and Francis Group, LLC.