Manipulating feedback on schizophrenia: Evidence from a Posner task.

Individuals with schizophrenia show difficulties in achieving vital objectives. Abnormal behavioral and emotional responses to environmental feedback may be some of the psychological mechanisms underlying this lack of goal attainment in schizophrenia. The present study aims to assess how different types of feedback may affect performance in a computerized affective Posner task (non-monetary vs. monetary rewards; contingent vs. non-contingent feedback). The sample was composed of 32 patients with schizophrenia and 35 controls. Reaction times and error rates were the behavioral measurements. The emotional experience was assessed through self-reported affective scales. The results indicated that: ii) the performance with monetary rewards was better than with non-monetary ones in all participants, especially in patients with schizophrenia when higher attentional resources are required (invalid trials). Second, all participants demonstrated faster reaction times, but higher error rates, with non-contingent feedback (frustration condition). Significantly, the schizophrenia group only equaled the controls performance in the non-contingent condition with monetary rewards. Additionally, the higher the negative symptoms were in patients, the worse performance they had under frustration. Third, discrepancies between performance and self-report affect were found in patients. Specifically, after the induction of frustration, the patients reported feeling better and having no arousal changes. Therefore, the findings suggest that, in schizophrenia: i) non-monetary rewards are relatively less important; ii) monetary rewards lessen the negative effects of frustration, iii) discrepancies in self-reported affective scales suggest an unrealistic self-evaluation made under frustration. These findings shed light on the underlying mechanisms of the lack of goal attainment in schizophrenia.

Gel-sol synthesis of rutile nanoparticles.

Titanium dioxide (TiO(2)) rutile nanoparticles were synthesized at temperatures below 100 °C using a gel-sol process that provides control of the final particles' characteristics, such as the nanoparticle size, morphology, crystal structure and crystallinity. The synthesized rutile nanoparticles were analyzed using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the gel-sol process allows control over the final nanoparticle characteristics with the proper choice of reaction parameters. The most profound influence on the nanoparticles' properties is achieved by the type and concentration of the acid used in the reaction mixture. The gel-sol synthesis resulted in anisotropic rutile nanoparticles that are 60-160 nm long, depending on the reaction parameters, and have an aspect ratio of about 5. A reaction mechanism is presented, explaining the influence of various reaction parameters on the characteristics of the TiO(2) nanoparticles.

Surface treated titanium dioxide nanoparticles as inorganic UV filters in sunscreen products.

TiO(2) nanoparticles were used in this research as an inorganic UV absorber for preparation of a sunscreen that ensures optically transparent films with adequate SPF. TiO(2) nanoparticles in rutile crystal form, produced in Cinkarna Celje, were used in this research. The elementary principle of the nanograde TiO(2) production is the sulphate synthesis process, which is upgraded for the synthesis of final nano product. TiO(2) nanoparticles were subsequently surface modified by coating with sodium silicate as the source of silica. The resulting silica coated TiO(2) nanoparticles were examined by scanning (SEM) and transmission electron microscopy (TEM). Uniform particles distribution and homogeneous amorphous coatings, formed in heterogeneous nucleation of silica molecules on the surface of TiO(2) nanoparticles, were observed. Sun-protection factor (SPF) of 28 was determined for sunscreen with incorporated 9.0 wt. % TiO(2) nanoparticles, surface treated with 5.0 wt. % silica according to the "Method for the In Vitro Determination of UVA Protection Provided by Sunscreen Products".