BackgroundMany researchers and clinicians have proposed using virtual reality (VR) in adjunct to in vivo exposure therapy to provide an innovative form of exposure to patients suffering from different psychological disorders. The rationale behind the 'virtual approach' is that real and virtual exposures elicit a comparable emotional reaction in subjects, even if, to date, there are no experimental data that directly compare these two conditions. To test whether virtual stimuli are as effective as real stimuli, and more effective than photographs in the anxiety induction process, we tested the emotional reactions to real food (RF), virtual reality (VR) food and photographs (PH) of food in two samples of patients affected, respectively, by anorexia (AN) and bulimia nervosa (BN) compared to a group of healthy subjects. The two main hypotheses were the following: (a) the virtual exposure elicits emotional responses comparable to those produced by the real exposure; (b) the sense of presence induced by the VR immersion makes the virtual experience more ecological, and consequently more effective than static pictures in producing emotional responses in humans.MethodsIn total, 10 AN, 10 BN and 10 healthy control subjects (CTR) were randomly exposed to three experimental conditions: RF, PH, and VR while their psychological (Stait Anxiety Inventory (STAI-S) and visual analogue scale for anxiety (VAS-A)) and physiological (heart rate, respiration rate, and skin conductance) responses were recorded.ResultsRF and VR induced a comparable emotional reaction in patients higher than the one elicited by the PH condition. We also found a significant effect in the subjects' degree of presence experienced in the VR condition about their level of perceived anxiety (STAI-S and VAS-A): the higher the sense of presence, the stronger the level of anxiety.ConclusionsEven though preliminary, the present data show that VR is more effective than PH in eliciting emotional responses similar to those expected in real life situations. More generally, the present study suggests the potential of VR in a variety of experimental, training and clinical contexts, being its range of possibilities extremely wide and customizable. In particular, in a psychological perspective based on a cognitive behavioral approach, the use of VR enables the provision of specific contexts to help patients to cope with their diseases thanks to an easily controlled stimulation.

3D arrays of close-packed AgBiS 2 quantum dots (QDs) in thin film form were synthesized for the first time using novel, convenient sonochemical approach. Structural, optical, and photoelectrical properties of the synthesized material were investigated with an emphasis on their dependence on crystal size. The sonochemically synthesized AgBiS 2 colloidal crystals have an average QD radius of 4.2 nm, twice as small compared to the QD solid obtained without ultrasonic irradiation. The optical band gap energy of sonochemically synthesized AgBiS 2 QD thin films of 1.40 eV is strongly blue-shifted in comparison to that of the macrocrystal (0.90 eV) and that of nanostructured films synthesized by conventional chemical route (1.10 eV). Upon annealing, E g exhibits a red shift to 1.00 eV. Spectral dependence of stationary nonequilibrium conductivity of the 3D QD assemblies suggests that the thin films' photoconductivity is modulated by the intercrystalline barrier height decrease. E g of the films calculated on the basis of photoconduction spectral response in the low-absorption region is 1.18 eV. Thermal band gap energy of the films is 1.10 eV, whereas both the variable range hopping conduction and thermionic emission mechanisms are predominant in the overall intercrystalline charge carrier transport through 3D QD assemblies.

The transport properties of nonequilibrium (photoexcited) charge carriers in sonochemically synthesized threedimensional (3D) assemblies of AgBiS 2 quantum dots (QDs) deposited as thin films were studied. To characterize the photoconduction of quantum-confined nanocrystals close packed in thin film form, both stationary and time-resolved experiments were performed. Besides by interband electronic transitions in the bulklike part of the nanocrystals, the photoresponse of nanocrystalline films was found to be also affected to a greater extent by the crystal boundary barrier height modulation upon illumination. The surface and bulk recombination velocities were found to be comparable. Good agreement was obtained between the band gap energy determined by analysis of the photoconductivity data measured by the constant field and the constant photocurrent method (∼1.18 eV). This value is in agreement with the optical spectroscopy data. It is higher than the optical band gap of a bulk specimen of this semiconductor, due to 3D confinement effects on the charge carrier motions within individual QDs. The nonequilibrium conductivity was found to relax exponentially with a time constant of 1.67 ms, which corresponds to average lifetime of minority charge carriers (holes).

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The Oxford Cognitive Screen (OCS) is a screening tool for the assessment of poststroke deficits in attention, memory, praxis, language, and number processing. The goal of the present study was to develop a Russian version of the OCS (Rus-OCS) via translation of the original battery, its cultural and linguistic adaptations, and reporting preliminary findings on its psychometric properties. Method: All parts of OCS were translated by native Russian-speaking neuropsychologists. Russian-speaking stroke patients (N ϭ 205) were assessed with the Rus-OCS. Their performance was compared with performance of 60 healthy Russian-speaking adults aged between the ages of 18 and 91 years. The performance of 15 stroke patients and 42 healthy adults were assessed with a parallel version within 7 days of first testing. Convergent validity of the Rus-OCS was established via correlations with comparable tasks. Performance of three stroke groups with different lesion lateralization (right, left, and bilateral) was compared on language and visual attention subtasks. Preliminary normative data based on 5th to 95th percentile were also reported. Results: Measures of internal consistency and test-retest reliability ranged from acceptable to very good and estimates of convergent validity ranged from moderate to high. Sensitivity and specificity was found to range from .56 to 1 and from .73 to 1, respectively. Significant differences in performance between stroke and healthy groups on all subtasks confirmed the discriminative power of the Rus-OCS was good. Conclusions: Rus-OCS is a promising cognitive screening instrument for Russian-speaking patients. However, further validation is needed. Constraints of socioeconomic differences between Russian speakers in the wider population should be considered.

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