Speech Reception in Young Children with Autism Is Selectively Indexed by a Neural Oscillation Coupling Anomaly.

Communication difficulties are one of the core criteria in diagnosing autism spectrum disorder (ASD), and are often characterized by speech reception difficulties, whose biological underpinnings are not yet identified. This deficit could denote atypical neuronal ensemble activity, as reflected by neural oscillations. Atypical cross-frequency oscillation coupling, in particular, could disrupt the joint tracking and prediction of dynamic acoustic stimuli, a dual process that is essential for speech comprehension. Whether such oscillatory anomalies already exist in very young children with ASD, and with what specificity they relate to individual language reception capacity is unknown. We collected neural activity data using electroencephalography (EEG) in 64 very young children with and without ASD (mean age 3; 17 females, 47 males) while they were exposed to naturalistic-continuous speech. EEG power of frequency bands typically associated with phrase-level chunking (δ, 1-3 Hz), phonemic encoding (low-γ, 25-35 Hz), and top-down control (ß, 12-20 Hz) were markedly reduced in ASD relative to typically developing (TD) children. Speech neural tracking by δ and θ (4-8 Hz) oscillations was also weaker in ASD compared with TD children. After controlling gaze-pattern differences, we found that the classical θ/γ coupling was replaced by an atypical ß/γ coupling in children with ASD. This anomaly was the single most specific predictor of individual speech reception difficulties in ASD children. These findings suggest that early interventions (e.g., neurostimulation) targeting the disruption of ß/γ coupling and the upregulation of θ/γ coupling could improve speech processing coordination in young children with ASD and help them engage in oral interactions.SIGNIFICANCE STATEMENT Very young children already present marked alterations of neural oscillatory activity in response to natural speech at the time of autism spectrum disorder (ASD) diagnosis. Hierarchical processing of phonemic-range and syllabic-range information (θ/γ coupling) is disrupted in ASD children. Abnormal bottom-up (low-γ) and top-down (low-ß) coordination specifically predicts speech reception deficits in very young ASD children, and no other cognitive deficit.

Strain-Engineered Oxygen Vacancies in CaMnO3 Thin Films.

We demonstrate a novel pathway to control and stabilize oxygen vacancies in complex transition-metal oxide thin films. Using atomic layer-by-layer pulsed laser deposition (PLD) from two separate targets, we synthesize high-quality single-crystalline CaMnO3 films with systematically varying oxygen vacancy defect formation energies as controlled by coherent tensile strain. The systematic increase of the oxygen vacancy content in CaMnO3 as a function of applied in-plane strain is observed and confirmed experimentally using high-resolution soft X-ray absorption spectroscopy (XAS) in conjunction with bulk-sensitive hard X-ray photoemission spectroscopy (HAXPES). The relevant defect states in the densities of states are identified and the vacancy content in the films quantified using the combination of first-principles theory and core-hole multiplet calculations with holistic fitting. Our findings open up a promising avenue for designing and controlling new ionically active properties and functionalities of complex transition-metal oxides via strain-induced oxygen-vacancy formation and ordering.

Experimental and computational X-ray emission spectroscopy as a direct probe of protonation states in oxo-bridged Mn(IV) dimers relevant to redox-active metalloproteins.

The protonation state of oxo bridges in nature is of profound importance for a variety of enzymes, including the Mn4CaO5 cluster of photosystem II and the Mn2O2 cluster in Mn catalase. A set of dinuclear bis-µ-oxo-bridged Mn(IV) complexes in different protonation states was studied by Kß emission spectroscopy to form the foundation for unraveling the protonation states in the native complex. The valence-to-core regions (valence-to-core XES) of the spectra show significant changes in intensity and peak position upon protonation. DFT calculations were performed to simulate the valence-to-core XES spectra and to assign the spectral features to specific transitions. The Kß(2,5) peaks arise primarily from the ligand 2p to Mn 1s transitions, with a characteristic low energy shoulder appearing upon oxo-bridge protonation. The satellite Kß" peak provides a more direct signature of the protonation state change, since the transitions originating from the 2s orbitals of protonated and unprotonated µ-oxo bridges dominate this spectral region. The energies of the Kß" features differ by ~3 eV and thus are well resolved in the experimental spectra. Additionally, our work explores the chemical resolution limits of the method, namely, whether a mixed (µ-O)(µ-OH2) motif can be distinguished from a symmetric (µ-OH)2 one. The results reported here highlight the sensitivity of Kß valence-to-core XES to single protonation state changes of bridging ligands, and form the basis for further studies of oxo-bridged polymetallic complexes and metalloenzyme active sites. In a complementary paper, the results from X-ray absorption spectroscopy of the same Mn(IV) dimer series are discussed.

Women's narratives on quality in prenatal care: a multicultural perspective.

Although significant progress has been made to increase prenatal care access, national organizations concerned with health equity emphasize that eliminating disparities will require greater attention to quality of care, assessed from both the biomedical and patient perspectives. In this study, we examined narratives about pregnancy experiences from low-income primiparous African American, Mexican American, Puerto Rican, and White women who participated in focus groups conducted in 1996. We reanalyzed transcripts from these discussions, extracting passages in which women talked about the content and quality of their prenatal care experiences. Data were mapped to four domains reflecting patient-centeredness markers identified in the 2005 U.S. National Healthcare Disparities Report (NHDR). These markers include the extent to which the women perceived that their provider listened carefully, explained things, showed respect, and spent enough time with them. The narratives provided by the study participants suggest a critical and intuitive understanding of the NHDR patient-centeredness markers and some shared understanding across cultural groups. Implications for improving quality and its measurement in prenatal care are discussed.