Virtual reality, or VR, allows users to experience a sense of presence in a computer-generated three-dimensional environment. Sensory information is delivered through a head mounted display and specialized interface devices. These devices track head movements so that the movements and images change in a natural way with head motion, allowing for a sense of immersion. VR allows for controlled delivery of sensory stimulation via the therapist and is a convenient and cost-effective treatment. The primary focus of this article is to review the available literature regarding the effectiveness of incorporating VR within the psychiatric treatment of a wide range of psychiatric disorders, with a specific focus on exposure-based intervention for anxiety disorders. A systematic literature search was conducted in order to identify studies implementing VR based treatment for anxiety or other psychiatric disorders. This review will provide an overview of the history of the development of VR based technology and its use within psychiatric treatment, an overview of the empirical evidence for VR based treatment, the benefits for using VR for psychiatric research and treatment, recommendations for how to incorporate VR into psychiatric care, and future directions for VR based treatment and clinical research.

Tantalum-oxide-based bi-layered resistance-change memories (RRAMs) have recently improved greatly with regard to their memory performances. The formation and rupture of conductive filaments is generally known to be the mechanism that underlies resistive switching. The nature of the filament has been studied intensively and several phenomenological models have consistently predicted the resistance-change behavior. However, a physics-based model that describes a complete bi-layered RRAM structure has not yet been demonstrated. Here, a complete electro-thermal resistive switching model based on the finite element method is proposed. The migration of oxygen vacancies is simulated by the local temperature and electric field derived from carrier continuity and heat equations fully coupled in a 3-D geometry, which considers a complete bi-layered structure that includes the top and bottom electrodes. The proposed model accurately accounts for the set/reset characteristics, which provides an in-depth understanding of the nature of resistive switching.

We investigate using first-principles calculations the atomic structure of the orthorhombic phase of Ta2O5. Although this structure has been studied for decades, the correct structural model is controversial owing to the complication of structural disorder. We identify a new low-energy highsymmetry structural model where all Ta and O atoms have correct formal oxidation states of +5 and −2, respectively, and the experimentally reported triangular lattice symmetry of the Ta sublattice appears dynamically at finite temperatures. To understand the complex atomic structure of the Ta2O3 plane, a triangular graph-paper representation is devised and used alongside oxidation state analysis to reveal infinite variations of the low-energy structural model. The structural disorder of Ta2O5 observed in experiments is attributed to the intrinsic structural variations, and oxygen vacancies that drive collective relaxation of the O sublattice.Tantalum pentoxide (Ta 2 O 5 ) is one of the most extensively studied transition metal oxides due to its potential for technological applications such as anti-reflection coatings, photocatalysis, and high-k dielectrics for highdensity transistors [1][2][3]. It has recently attracted interest as the material of choice for resistance-change memory and the related memristor [4][5][6], however, its crystalline structure, which is critical to its unique structural and electronic properties, is still unclear.Ta 2 O 5 has an orthorhombic phase up to ∼ 1350 • C, above which a transition to a tetragonal phase occurs [7,8]. Although the low-temperature orthorhombic phase is of technological relevance, it has proven difficult to characterize structurally. Early X-ray diffraction studies [9,10] found that the orthorhombic Ta 2 O 5 phase consists of two-dimensional (2D) layers of Ta 2 O 3 in the ab plane, and two-fold coordinated O atoms that connect the Ta atoms in adjacent layers (forming linear chains of -Ta-O-Ta-O-Ta-) along the c direction. In the Ta 2 O 3 plane, it was understood that the Ta atoms form a triangular arrangement, but the arrangement of O atoms was unresolved, with many weak superstructure lines [10]. Later, Roth and coworkers reported that the Ta 2 O 3 plane consists of a disordered array of Ta atoms in octahedral and pentagonal bipyramidal arrangements, with an 11-fold increase of the lattice parameters in the b direction [11]. The superstructure periodicity was shown to change when aliovalent cations, such as W or Li, were incorporated in small amounts to stabilize the phase [12,13]. The superstructures consist of a set of small-unit basic structures and invoked the concept of infinitely adaptive structures [14] for nonstoichiometric Ta 2 O 5−x thatwithin certain composition limits-every composition orders into a different superstructure.Extensive theoretical studies have been made with regards to the bulk properties, dielectric response, and oxygen vacancies (and their diffusion) of Ta 2 O 5 [15][16][17][18][19][20][21][22][23]. In these studies, the low-temperature Ta 2 O 5 pha...

These results suggest that memory reactivation prior to exposure therapy did not have an impact on clinical measures but may enhance the effect of exposure therapy at the physiological level.

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