A Satisfaction-based Model for Affect Recognition from Conversational Features in Spoken Dialog Systems

Detecting user affect automatically during real-time conversation is the main challenge towards our greater aim of infusing social intelligence into a natural-language mixed-initiative High-Fidelity (Hi-Fi) audio control spoken dialog agent. In recent years, studies on affect detection from voice have moved on to using realistic, non-acted data, which is subtler. However, it is more challenging to perceive subtler emotions and this is demonstrated in tasks such as labelling and machine prediction. This paper attempts to address part of this challenge by considering the role of user satisfaction ratings and also conversational/dialog features in discriminating contentment and frustration, two types of emotions that are known to be prevalent within spoken human-computer interaction. However, given the laboratory constraints, users might be positively biased when rating the system, indirectly making the reliability of the satisfaction data questionable. Machine learning experiments were conducted on two datasets, users and annotators, which were then compared in order to assess the reliability of these datasets. Our results indicated that standard classifiers were significantly more successful in discriminating the abovementioned emotions and their intensities (reflected by user satisfaction ratings) from annotator data than from user data. These results corroborated that: first, satisfaction data could be used directly as an alternative target variable to model affect, and that they could be predicted exclusively by dialog features. Second, these were only true when trying to predict the abovementioned emotions using annotator?s data, suggesting that user bias does exist in a laboratory-led evaluation

Differential Expression Levels of Integrin α6 Enable the Selective Identification and Isolation of Atrial and Ventricular Cardiomyocytes

<div><p>Rationale</p><p>Central questions such as cardiomyocyte subtype emergence during cardiogenesis or the availability of cardiomyocyte subtypes for cell replacement therapy require selective identification and purification of atrial and ventricular cardiomyocytes. However, current methodologies do not allow for a transgene-free selective isolation of atrial or ventricular cardiomyocytes due to the lack of subtype specific cell surface markers.</p><p>Methods and Results</p><p>In order to develop cell surface marker-based isolation procedures for cardiomyocyte subtypes, we performed an antibody-based screening on embryonic mouse hearts. Our data indicate that atrial and ventricular cardiomyocytes are characterized by differential expression of integrin α6 (ITGA6) throughout development and in the adult heart. We discovered that the expression level of this surface marker correlates with the intracellular subtype-specific expression of MLC-2a and MLC-2v on the single cell level and thereby enables the discrimination of cardiomyocyte subtypes by flow cytometry. Based on the differential expression of ITGA6 in atria and ventricles during cardiogenesis, we developed purification protocols for atrial and ventricular cardiomyocytes from mouse hearts. Atrial and ventricular identities of sorted cells were confirmed by expression profiling and patch clamp analysis.</p><p>Conclusion</p><p>Here, we introduce a non-genetic, antibody-based approach to specifically isolate highly pure and viable atrial and ventricular cardiomyocytes from mouse hearts of various developmental stages. This will facilitate in-depth characterization of the individual cellular subsets and support translational research applications.</p></div

List of fold-change values of selected genes with general or subtype-specific expression in mouse cardiomyocytes.

<p>Positive fold-change values indicate a higher abundance in ITGA6^high as compared to ITGA6^low-sorted cells, negative values demonstrate a higher abundance in ITGA6^low-sorted cells in comparison to ITGA6^high. Differential gene expression was assumed for fold-change values ≥ 3.0 or ≤ -3.0.</p><p>List of fold-change values of selected genes with general or subtype-specific expression in mouse cardiomyocytes.</p

Gene expression analysis of sorted cells confirms selective enrichment of atrial and ventricular cardiomyocytes.

<p><b>(A)</b> Normalized signal intensities of CM-specific marker genes: general CM-specific <i>Tnnt2</i> and <i>Nkx2-5</i>, ventricle-specific <i>Hey2</i> and <i>Irx4</i>, atrium-specific <i>Nr2f2</i> and <i>Fgf12</i>. Data are expressed as mean ± SD, n = 4. Statistical analysis: ANOVA, Benjamini-Hochberg correction for multiple testing p ≤ 0.05, Tukey post-hoc test *** p ≤ 0.001, ns = not significant. <b>(B)</b> Heat-map shows median-centered log2-transformed signal intensities of selected genes. The color code indicates expression relative to the gene-wise median of all samples. Abbreviation: EL = E15.5 ERBB-2⁺/ITGA6^low, EH = E15.5 ERBB-2⁺/ITGA6^high, PL = P2 ITGA6^low, PH = P2 ITGA6^high.</p

Differential expression of ITGA5 and ITGA6 on atrial and ventricular cardiomyocytes.

<p><b>(A)</b> E13.5 whole hearts and mechanically separated atrial and ventricular tissue were co-labeled for ITGA6 or ITGA5 and α-actinin. Histograms, ITGA6 or ITGA5 expression gated on α-actinin+ cells. <b>(B)</b> E13.5 whole-heart preparations co-stained with antibodies against ITGA6 or ITGA5 and MLC-2a or MLC-2v (labeled with AlexaFluor^® 488 goat anti-mouse IgG). Analysis gates set according to the secondary antibody control. Rectangles indicate ITGA6 low (green) and high (red) expressing myocytes. <b>(C)</b> Co-labeling of E11.5 –P2 mouse hearts for ITGA6 and α-actinin.</p

Functional subtype characterization of sorted cells confirms selective enrichment of atrial and ventricular cardiomyocytes.

<p><b>(A)</b> Top graph, typical ventricular-like action potential (AP) of a cell from the EL group. Bottom graph, typical atrial-like AP from a CMs of the EH group. <b>(B)</b> Distribution of the cells in the two sorted groups. <b>(C)</b> Statistical analysis of AP parameters: left, action potential duration at 90% of repolarization (ADP90); mid, maximum rate of rise of the AP (max dV/dt); right, maximum diastolic polarization (MDP). Data are expressed as mean ± SEM. *** p ≤ 0.001 EL vs. EH. <b>(D)</b> Representative voltage ramps recordings from an E15.5 ERBB-2⁺/ITGA6^low CM (left) and an E15.5 ERBB-2⁺/ITGA6^high CM (right) show functional expression of inward and outward current components. Abbreviation: EL = E15.5 ERBB-2⁺/ITGA6^low, EH = E15.5 ERBB-2⁺/ITGA6^high, PL = P2 ITGA6^low, PH = P2 ITGA6^high.</p