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Adolescents frequently engage in high-risk behaviours (HRB) following childhood sexual abuse (CSA). Aberrant reward processes are implicated in HRB, and their underlying fronto-striatal networks are vulnerable to neurodevelopmental changes during adversity representing a promising candidate for understanding links between CSA and HRB. We examined whether fronto-striatal responses during reward anticipation and feedback (i) are altered in depressed adolescents with CSA compared to depressed, non-abused peers and (ii) moderate the relationship between CSA and HRB irrespective of depression. Forty-eight female adolescents {14 with CSA and depression [CSA + major depressive disorder (MDD)]; 17 with MDD but no CSA (MDD); 17 healthy, non-abused controls} completed a monetary reward task during functional magnetic resonance imaging. No differences in fronto-striatal response to reward emerged between CSA + MDD and MDD. Critically, high left nucleus accumbens activation during reward anticipation was associated with greater HRB in CSA + MDD compared to MDD and controls. Low left putamen activation during reward feedback was associated with the absence of HRB in CSA + MDD compared to MDD. Striatal reward responses appear to play a key role in HRB for adolescents with CSA irrespective of depression, providing initial support for a CSA ecophenotype. Such information is pivotal to identify at-risk youth and prevent HRB in adolescents after CSA.

Block copolymer (BCP) self-assembly produces chemically and topographically patterned surfaces which are used to guide the formation of Cu nanostructures by exploiting differences in the mobility of vapor-deposited species on each microdomain. Cu metal films a few nm thick were deposited on three different BCP surfaces self-assembled from poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP). For PS-b-PMMA, the effects of chemical heterogeneity dominate over the effects of the 2 nm peak-to-valley topography, and sputtered Cu preferentially wets the PS block. PS-b-P2VP has greater chemical and topographical contrast and shows a wider process window for selective deposition. Cu grown by evaporation has less surface mobility, and shadowing effects are believed to dominate pattern formation. The hierarchical self-assembly process of thin metal films on BCP surfaces provides a route to fabricating heterogeneous metallic nanostructures.

Diblock Janus-type "A

Single-phase multiferroic materials that allow the coexistence of ferroelectric and magnetic ordering above room temperature are highly desirable, motivating an ongoing search for mechanisms for unconventional ferroelectricity in magnetic oxides. Here, we report an antisite defect mechanism for room temperature ferroelectricity in epitaxial thin films of yttrium orthoferrite, YFeO3, a perovskite-structured canted antiferromagnet. A combination of piezoresponse force microscopy, atomically resolved elemental mapping with aberration corrected scanning transmission electron microscopy and density functional theory calculations reveals that the presence of YFe antisite defects facilitates a non-centrosymmetric distortion promoting ferroelectricity. This mechanism is predicted to work analogously for other rare earth orthoferrites, with a dependence of the polarization on the radius of the rare earth cation. Our work uncovers the distinctive role of antisite defects in providing a mechanism for ferroelectricity in a range of magnetic orthoferrites and further augments the functionality of this family of complex oxides for multiferroic applications., Ferroelectricity in orthoferrite perovskites has stimulated intense research, but the mechanism remains unclear. Here, the authors propose an antisite defect mechanism for introducing ferroelectricity in magnetically ordered YFeO3 and the family of rare earth orthoferrites.

The formation of zigzags, chevrons, Y-junctions, and line segments is demonstrated in thin films formed from cylindrical morphology silicon-containing conformationally asymmetric rod-coil diblock copolymers and triblock terpolymers under solvent annealing. Directed self-assembly of the block copolymers within trenches yields well-ordered cylindrical microdomains oriented either parallel or transverse to the sidewalls depending on the chemical functionalization of the sidewalls, and the location and structure of concentric bends in the cylinders is determined by the shape of the trenches. The innate etching contrast, the spontaneous sharp bends and junctions, and the range of demonstrated periodicity and line/space ratios make these conformationally asymmetric rod-coil polymers attractive for nanoscale pattern generation.

Block copolymer self-assembly is a powerful tool for 2D nanofabrication; however, its extension to complex 3D network structures, which would be useful for a range of applications, is limited. Here, we report a simple method to generate unprecedented 3D mesh morphologies through intrinsic molecular confinement self-assembly. We designed triblock bottlebrush polymers with two Janus domains: one perpendicular and one parallel to the polymer backbone. The former enforces a lamellar superstructure that intrinsically confines the intra-layer self-assembly of the latter, giving rise to a mesh-like monoclinic M15 network substructure with excellent long-range order. Dissipative particle dynamics simulations show that the spatial constraints exerted on the polymer backbone drive the emergence of M15, as well as a tetragonal T131 in the strong segregation regime. This work demonstrates intrinsic molecular confinement as a path to bottom-up assembly of new geometrical phases of soft matter, extending the capabilities of block copolymer nanofabrication.

The self-assembly of multiblock copolymers generates diverse hierarchical nanostructures and greatly extends the range of microdomain geometries beyond those produced by diblock copolymers. We report the synthesis of a conformationally asymmetric ABC triblock terpolymer in which the end blocks are a mesogen-jacketed liquid crystalline polymer and poly(dimethylsiloxane), respectively, and its self-assembly under mixed solvent vapor annealing forms a range of sphere, cylinder, and perforated lamellar core-shell morphologies, as well as stacked multilevel structures. Sub-7 nm diameter SiO

The creation of structural composites with combined strength, toughness, low density, and biocompatibility remains a long-standing challenge. On the other hand, bivalve marine shells—Clinocardium s...

Searching for new materials and phenomena to enable voltage control of magnetism and magnetic properties holds compelling interest for the development of low-power nonvolatile memory devices. In particular, reversible and nonvolatile ON/OFF controls of magnetism above room temperature are highly desirable yet still elusive. Here, we report on a nonvolatile voltage control of magnetism in epitaxial SrCo1-xFexO3-δ (SCFO). The substitution of Co with Fe significantly changes the magnetic properties of SCFO. In particular, for the Co/Fe ratio of ∼1:1, a switch between nonmagnetic (OFF) and ferromagnetic (ON) states with a Curie temperature above room temperature is accomplished by ionic liquid gating at ambient conditions with voltages as low as ±2 V, even for films with thickness up to 150 nm. Tuning the oxygen stoichiometry via the polarity and duration of gating enables reversible and continuous control of the magnetization between 0 and 100 emu/cm3 (0.61 μB/f.u.) at room temperature. In addition, SCFO was successfully incorporated into self-assembled two-phase vertically aligned nanocomposites, in which the reversible voltage control of magnetism above room temperature is also attained. The notable structural response of SCFO to ionic liquid gating allows large strain couplings between the two oxides in these nanocomposites, with potential for voltage-controlled and strain-mediated functionality based on couplings between structure, composition, and physical properties.

Silicon-containing block copolymer thin films with high interaction parameter and etch contrast are ideal candidates to generate robust nanotemplates for advanced nanofabrication, but they typically form in-plane oriented microdomains as a result of the dissimilar surface energies of the blocks. Here, we describe a two-step annealing method to produce vertically aligned lamellar structures in thin film of a silicon-containing rod–coil thermotropic liquid crystalline block copolymer. The rod–coil block copolymer with the volume fraction of the Si-containing block of 0.22 presents an asymmetrical lamellar structure in which the rod block forms a hexatic columnar nematic liquid crystalline phase. A solvent vapor annealing step first produces well-ordered in-plane cylinders of the Si-containing block, then a subsequent thermal annealing promotes the phase transition from in-plane cylinders to vertical lamellae. The pathways of the order–order transition were examined by microscopy and in situ using grazing incidence small-angle X-ray scattering and wide-angle X-ray scattering.

Complex-oxide materials exhibit a vast range of functional properties desirable for next-generation electronic, spintronic, magnetoelectric, neuromorphic, and energy conversion storage devices1-4. Their physical functionalities can be coupled by stacking layers of such materials to create heterostructures and can be further boosted by applying strain5-7. The predominant method for heterogeneous integration and application of strain has been through heteroepitaxy, which drastically limits the possible material combinations and the ability to integrate complex oxides with mature semiconductor technologies. Moreover, key physical properties of complex-oxide thin films, such as piezoelectricity and magnetostriction, are severely reduced by the substrate clamping effect. Here we demonstrate a universal mechanical exfoliation method of producing freestanding single-crystalline membranes made from a wide range of complex-oxide materials including perovskite, spinel and garnet crystal structures with varying crystallographic orientations. In addition, we create artificial heterostructures and hybridize their physical properties by directly stacking such freestanding membranes with different crystal structures and orientations, which is not possible using conventional methods. Our results establish a platform for stacking and coupling three-dimensional structures, akin to two-dimensional material-based heterostructures, for enhancing device functionalities8,9.

The combination of block copolymer (BCP) thin film self-assembly and selective infiltration synthesis of inorganic materials into one BCP block provides access to various organic-inorganic hybrids. Here, we apply sequential infiltration synthesis, a vapor-phase hybridization technique, to selectively introduce ZnO into the organic microdomains of silicon-containing rod-coil diblock copolymers and a triblock terpolymer, polydimethylsiloxane (PDMS)

Magnetic patterns can be controlled globally using fields or spin polarized currents. In contrast, the local control of the magnetization on the nanometer length scale remains challenging. Here, we demonstrate how magnetic domain patterns in a Tm-doped yttrium iron garnet (Tm:YIG) thin film with perpendicular magnetic anisotropy can be permanently and locally imprinted by high intensity photon pulses of a hard x-ray transient grating (XTG). Micromagnetic simulations provide a qualitative understanding of the observed changes in the orientation of magnetic domains in Tm:YIG and XTG-induced changes. The presented results offer a route for the local manipulation of the magnetic state using hard XTG., Comment: 15 pages, 3 figures

Long noncoding RNAs (lncRNAs) are products of pervasive transcription that closely resemble messenger RNAs on the molecular level, yet function through largely unknown modes of action. The current model is that the function of lncRNAs often relies on specific, typically short, conserved elements, connected by linkers in which specific sequences and/or structures are less important. This notion has fueled the development of both computational and experimental methods focused on the discovery of functional elements within lncRNA genes, based on diverse signals such as evolutionary conservation, predicted structural elements, or the ability to rescue loss-of-function phenotypes. In this review, we outline the main challenges that the different methods need to overcome, describe the recently developed approaches, and discuss their respective limitations. This article is categorized under: RNA Evolution and GenomicsComputational Analyses of RNA RNA Interactions with Proteins and Other MoleculesProtein-RNA Interactions: Functional Implications Regulatory RNAs/RNAi/RiboswitchesRegulatory RNAs.

Block copolymer (BCP) self-assembly produces chemically and topographically patterned surfaces which are used to guide the formation of Cu nanostructures by exploiting differences in the mobility of vapor-deposited species on each microdomain. Cu metal films a few nm thick were deposited on three different BCP surfaces self-assembled from poly(styrene

The directed self-assembly of block copolymers (BCPs) is a powerful motif for the continued scaling of feature sizes for nanoscale devices. A multimechanism directed self-assembly (MMDSA) method is described that generates orthogonal meshes from a polystyrene-b-poly-2-vinylpyridine BCP that is subsequently metallized with Pt. The MMDSA process takes advantage of three different mechanisms, trench wall guidance, edge nucleation, and underlayer guidance, to align the mesh with respect to substrate features. The mechanisms and their interactions are investigated via both experiments and dissipative particle dynamics simulations. MMDSA is applied to produce well-aligned conductive nanomeshes and then is extended to fabricate multicomponent metallic structures with 2D/3D hybrid morphologies.

Voltage-tuning of magnetic anisotropy is demonstrated in ferrimagnetic insulating rare earth iron garnets on a piezoelectric substrate, (011)-oriented PMN-PT. A 42 nm thick yttrium-substituted dysprosium iron garnet (YDyIG) film is grown via pulsed laser deposition followed by a rapid thermal anneal to crystallize the garnet into ≈5 μm diameter grains. The annealed polycrystalline film is magnetically isotropic in the film plane with total anisotropy dominated by shape and magnetoelastic contributions. Application of an electric field perpendicular to the substrate breaks the in-plane easy axis along [01[Formula: see text]] and an intermediate axis along [100]. The results are explained in terms of the piezoelectric remanent strain caused by poling the substrate, which is transferred to the YDyIG and modulates the magnetoelastic anisotropy.

Yttrium iron garnet (YIG) and barium titanate (BTO) were co-deposited on (001)-orientated gadolinium gallium garnet substrates by pulsed laser deposition with composition determined by the ratio of laser shots ablating each target. With increasing shot ratios of YIG/BTO = 2.5/1, 4/1, 20/1, and 30/1, the majority phase in the film changes from textured polycrystalline perovskite to epitaxial garnet. Cross-sectional STEM characterization of the YIG-rich films reveals three distinct sublayers: the bottom layer is a coherent epitaxial garnet layer with higher unit cell volume than that of YIG; the second layer is garnet exhibiting crystalline defects and misorientation; and the upper layer is amorphous. Highly defective regions within the second layer are richer in Ba, suggesting that the microstructure is promoted by the insolubility of Ba in YIG. Temperature-dependent magnetization measurements fitted to a super-exchange dilution model indicate the presence of nonmagnetic Ti and vacancies in both octahedral and tetrahedral sites.