Looming motion is an ecologically salient signal that often signifies danger. In both audition and vision, humans show behavioral biases in response to perceiving looming motion, which is suggested ...to indicate an adaptation for survival. However, it is an open question whether such biases occur also in the combined processing of multisensory signals. Towards this aim, Cappe, Thut, Romei, and Murraya (2009) found that responses to audiovisual signals were faster for congruent looming motion compared to receding motion or incongruent combinations. They considered this as evidence for selective integration of multisensory looming signals. To test this proposal, here, we successfully replicate the behavioral results by Cappe et al. (2009). We then show that the redundant signals effect (RSE - a speedup of multisensory compared to unisensory responses) is not distinct for congruent looming motion. Instead, as predicted by a simple probability summation rule, the RSE is primarily modulated by the looming bias in audition, which suggests that multisensory processing inherits a unisensory effect. Finally, we compare a large set of so-called race models that implement probability summation, but that allow for interference between auditory and visual processing. The best-fitting model, selected by the Akaike Information Criterion (AIC), virtually perfectly explained the RSE across conditions with interference parameters that were either constant or varied only with auditory motion. In the absence of effects jointly caused by auditory and visual motion, we conclude that selective integration is not required to explain the behavioral benefits that occur with audiovisual looming motion.
Diarrhea-predominant irritable bowel syndrome (IBS) is diagnosed through clinical criteria after excluding "organic" conditions, and can be precipitated by acute gastroenteritis. Cytolethal ...distending toxin B (CdtB) is produced by bacteria that cause acute gastroenteritis, and a post-infectious animal model demonstrates that host antibodies to CdtB cross-react with vinculin in the host gut, producing an IBS-like phenotype. Therefore, we assessed circulating anti-CdtB and anti-vinculin antibodies as biomarkers for D-IBS in human subjects. Subjects with D-IBS based on Rome criteria (n=2375) were recruited from a large-scale multicenter clinical trial for D-IBS (TARGET 3). Subjects with inflammatory bowel disease (IBD) (n=142), subjects with celiac disease (n=121), and healthy controls (n=43) were obtained for comparison. Subjects with IBD and celiac disease were recruited based on the presence of intestinal complaints and histologic confirmation of chronic inflammatory changes in the colon or small intestine. Subjects with celiac disease were also required to have an elevated tTG and biopsy. All subjects were aged between 18 and 65 years. Plasma levels of anti-CdtB and anti-vinculin antibodies were determined by ELISA, and compared between groups. Anti-CdtB titers were significantly higher in D-IBS subjects compared to IBD, healthy controls and celiac disease (P<0.001). Anti-vinculin titers were also significantly higher in IBS (P<0.001) compared to the other groups. The area-under-the-receiver operating curves (AUCs) were 0.81 and 0.62 for diagnosis of D-IBS against IBD for anti-CdtB and anti-vinculin, respectively. Both tests were less specific in differentiating IBS from celiac disease. Optimization demonstrated that for anti-CdtB (optical density≥2.80) the specificity, sensitivity and likelihood ratio were 91.6%, 43.7 and 5.2, respectively, and for anti-vinculin (OD≥1.68) were 83.8%, 32.6 and 2.0, respectively. These results confirm that anti-CdtB and anti-vinculin antibodies are elevated in D-IBS compared to non-IBS subjects. These biomarkers may be especially helpful in distinguishing D-IBS from IBD in the workup of chronic diarrhea.
Diffusion tensor imaging (DTI) can be used to investigate cerebral structural connectivity in never-medicated individuals with first-episode schizophrenia.
Subjects with first-episode schizophrenia ...according to DSM-IV-R who had never been exposed to antipsychotic medication (n=25) and healthy controls (n=26) were recruited. Groups were matched for age, gender, best parental socio-economic status and ethnicity. All subjects underwent DTI and structural magnetic resonance imaging (MRI) scans. Voxel-based analysis was performed to investigate brain regions where fractional anisotropy (FA) values differed significantly between groups. A confirmatory region-of-interest (ROI) analysis of FA scores was performed in which regions were placed blind to group membership.
In patients, FA values significantly lower than those in healthy controls were located in the left fronto-occipital fasciculus, left inferior longitudinal fasciculus, white matter adjacent to right precuneus, splenium of corpus callosum, right posterior limb of internal capsule, white matter adjacent to right substantia nigra, and left cerebral peduncle. ROI analysis of the corpus callosum confirmed that the patient group had significantly lower mean FA values than the controls in the splenium but not in the genu. The intra-class correlation coefficient (ICC) for independent ROI measurements was 0.90 (genu) and 0.90 (splenium). There were no regions where FA values were significantly higher in the patients than in the healthy controls.
Widespread structural dysconnectivity, including the subcortical region, is already present in neuroleptic-naive patients in their first episode of illness.
Sintered silver is a promising die-attach material capable of operating at temperatures of more than 200°C. However, while sintering reliably bonds Ag paste on Ag-plated substrate, reliability ...studies are needed to understand the behavior of this sintered bond on copper and direct bond copper (DBC) substrates. Here, we thermally cycled micron-Ag and nano-Ag joints created via sintering on Cu, DBC, and Ag-plated substrates between − 65°C and 150°C in order to understand their evolving microstructures and reliability. Short periods at high temperature did not oxidize the substrate, but the absence of copper oxides did not prevent adhesive failure of the nano-Ag joint at the Cu interface. We found that Ag filler size influences pore shapes, pore sizes, and shear strength; the micron-Ag joint produced a mixture of irregular and regular spherical pore shapes that reduced bond strength more than the predominantly spherical pores present in the nano-Ag joint.
We investigated cerebral structural connectivity and its relationship to symptoms in never-medicated individuals with first-onset schizophrenia using diffusion tensor imaging (DTI).
We recruited ...subjects with first episode DSM-IV schizophrenia who had never been exposed to antipsychotic medication (n=34) and age-matched healthy volunteers (n=32). All subjects received DTI and structural magnetic resonance imaging scans. Patients' symptoms were assessed on the Positive and Negative Syndrome Scale. Voxel-based analysis was performed to investigate brain regions where fractional anisotropy (FA) values significantly correlated with symptom scores.
In patients with first-episode schizophrenia, positive symptoms correlated positively with FA scores in white matter associated with the right frontal lobe, left anterior cingulate gyrus, left superior temporal gyrus, right middle temporal gyrus, right middle cingulate gyrus, and left cuneus. Importantly, FA in each of these regions was lower in patients than controls, but patients with more positive symptoms had FA values closer to controls. We found no significant correlations between FA and negative symptoms.
The newly-diagnosed, neuroleptic-naive patients had lower FA scores in the brain compared with controls. There was positive correlation between FA scores and positive symptoms scores in frontotemporal tracts, including left fronto-occipital fasciculus and left inferior longitudinal fasciculus. This implies that white matter dysintegrity is already present in the pre-treatment phase and that FA is likely to decrease after clinical treatment or symptom remission.
In this work, a high temperature THz detector based on a GaN high electron mobility transistor (HEMT) with nano antenna structures was fabricated and demonstrated to be able to work up to 200
°C. The ...THz responsivity and noise equivalent power (NEP) of the device were characterized at 0.14 THz radiation over a wide temperature range from room temperature to 200 °C. A high responsivity R
of 15.5 and 2.7 kV/W and a low NEP of 0.58 and 10 pW/Hz
were obtained at room temperature and 200 °C, respectively. The advantages of the GaN HEMT over other types of field effect transistors for high temperature terahertz detection are discussed. The physical mechanisms responsible for the temperature dependence of the responsivity and NEP of the GaN HEMT are also analyzed thoroughly.
Background: Individuals with autism have impairments in 3 domains: communication, social interaction and repetitive behaviours. Our previous work suggested early structural and connectivity ...abnormalities in prefrontal‐striato‐temporal‐cerebellar networks but it is not clear how these are linked to diagnostic indices.
Method: Children with autism (IQ > 70) aged 6 to 14 years old and matched typically developing controls were studied using diffusion tensor imaging. Voxel‐based methods were used to compare fractional anisotrophy (FA) measures in each group and to correlate FA measures in the autism group with the diagnostic phenotype described by the Autism Diagnostic Interview – Revised (ADI‐R) algorithm for ICD‐10.
Results: After controlling for the effects of age and white matter volume, we found that FA in the autism group was significantly lower than controls in bilateral prefrontal and temporal regions, especially in the right ventral temporal lobe adjacent to the fusiform gyrus. FA was greater in autism in the right inferior frontal gyrus and left occipital lobe. We observed a tight correlation between lower FA and higher ADI‐R diagnostic algorithm scores across white matter tracts extending from these focal regions of group difference. Communication and social reciprocity impairments correlated with lower FA throughout fronto‐striato‐temporal pathways. Repetitive behaviours correlated with white matter indices in more posterior brain pathways, including splenium of the corpus callosum and cerebellum.
Conclusions: Our data support the position that diagnostic symptoms of autism are associated with a core disruption of white matter development.
It is not clear whether the progressive changes in brain microstructural deficits documented in previous longitudinal magnetic resonance imaging (MRI) studies might be due to the disease process or ...to other factors such as medication. It is important to explore the longitudinal alterations in white-matter (WM) microstructure in antipsychotic-naive patients with first-episode schizophrenia during the very early phase of treatment when relatively 'free' from chronicity.
Thirty-five patients with first-episode schizophrenia and 22 healthy volunteers were recruited. High-resolution diffusion tensor imaging (DTI) was obtained from participants at baseline and after 6 weeks of treatment. A 'difference map' for each individual was calculated from the 6-week follow-up fractional anisotropy (FA) of DTI minus the baseline FA. Differences in Positive and Negative Syndrome Scale (PANSS) scores and Global Assessment of Functioning (GAF) scores between baseline and 6 weeks were also evaluated and expressed as a 6-week/baseline ratio.
Compared to healthy controls, there was a significant decrease in absolute FA of WM around the bilateral anterior cingulate gyrus and the right anterior corona radiata of the frontal lobe in first-episode drug-naive patients with schizophrenia following 6 weeks of treatment. Clinical symptoms improved during this period but the change in FA did not correlate with the changes in clinical symptoms or the dose of antipsychotic medication.
During the early phase of treatment, there is an acute reduction in WM FA that may be due to the effects of antipsychotic medications. However, it is not possible to entirely exclude the effects of underlying progression of illness.
Recent years have seen great advances in our ability to predict crystal structures from first principles. However, previous algorithms have focused on the prediction of bulk crystal structures, where ...the global minimum is the target. Here, we present a general atomistic approach to simulate in multicomponent systems the structures and free energies of grain boundaries and heterophase interfaces with fixed stoichiometric and non-stoichiometric compositions. The approach combines a new genetic algorithm using empirical interatomic potentials to explore the configurational phase space of boundaries, and thereafter refining structures and free energies with first-principles electronic structure methods. We introduce a structural order parameter to bias the genetic algorithm search away from the global minimum (which would be bulk crystal), while not favouring any particular structure types, unless they lower the energy. We demonstrate the power and efficiency of the algorithm by considering non-stoichiometric grain boundaries in a ternary oxide, SrTiO(3).
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