African American Ethnic and Class-Based Identities on the World Wide Web: Moderating the Effects of Self-Perceived Information Seeking/Finding and Web Self-Efficacy

The web is a potentially powerful tool for communicating information to diverse audiences. Unfortunately, all groups are not equally represented on the web, and this may have implications for online information seeking. This study investigated the role of class- and ethnic-based identity in self-perceived web-based information seeking/finding and self-efficacy. A questionnaire is administered, asking African Americans about their class and ethnic identities and web use to test a conceptual model predicting that these identities are positively related to web-based information seeking and web self-efficacy, which are then positively related to web-based information finding. Gender and previous web experience are expected to moderate the relationships. Structural equations modeling of these data support most of the predictions and indicate that these identities influence perceptions of online information seeking

The Effect of OPA1 on Mitochondrial Ca2+ Signaling

The dynamin-related GTPase protein OPA1, localized in the intermembrane space and tethered to the inner membrane of mitochondria, participates in the fusion of these organelles. Its mutation is the most prevalent cause of Autosomal Dominant Optic Atrophy. OPA1 controls the diameter of the junctions between the boundary part of the inner membrane and the membrane of cristae and reduces the diffusibility of cytochrome c through these junctions. We postulated that if significant Ca2+ uptake into the matrix occurs from the lumen of the cristae, reduced expression of OPA1 would increase the access of Ca2+ to the transporters in the crista membrane and thus would enhance Ca2+ uptake. In intact H295R adrenocortical and HeLa cells cytosolic Ca2+ signals evoked with K+ and histamine, respectively, were transferred into the mitochondria. The rate and amplitude of mitochondrial [Ca2+] rise (followed with confocal laser scanning microscopy and FRET measurements with fluorescent wide-field microscopy) were increased after knockdown of OPA1, as compared with cells transfected with control RNA or mitofusin1 siRNA. Ca2+ uptake was enhanced despite reduced mitochondrial membrane potential. In permeabilized cells the rate of Ca2+ uptake by depolarized mitochondria was also increased in OPA1-silenced cells. The participation of Na+/Ca2+ and Ca2+/H+ antiporters in this transport process is indicated by pharmacological data. Altogether, our observations reveal the significance of OPA1 in the control of mitochondrial Ca2+ metabolism

Split T Cell Tolerance against a Self/Tumor Antigen: Spontaneous CD4+ but Not CD8+ T Cell Responses against p53 in Cancer Patients and Healthy Donors

Analyses of NY-ESO-1-specific spontaneous immune responses in cancer patients revealed that antibody and both CD4+ and CD8+ T cell responses were induced together in cancer patients. To explore whether such integrated immune responses are also spontaneously induced for other tumor antigens, we have evaluated antibody and T cell responses against self/tumor antigen p53 in ovarian cancer patients and healthy individuals. We found that 21% (64/298) of ovarian cancer patients but no healthy donors showed specific IgG responses against wild-type p53 protein. While none of 12 patients with high titer p53 antibody showed spontaneous p53-specific CD8+ T cell responses following a single in vitro sensitization, significant p53-specific IFN-γ producing CD4+ T cells were detected in 6 patients. Surprisingly, similar levels of p53-specific CD4+ T cells but not CD8+ T cells were also detected in 5/10 seronegative cancer patients and 9/12 healthy donors. Importantly, p53-specific CD4+ T cells in healthy donors originated from a CD45RA− antigen-experienced T cell population and recognized naturally processed wild-type p53 protein. These results raise the possibility that p53-specific CD4+ T cells reflect abnormalities in p53 occurring in normal individuals and that they may play a role in processes of immunosurveillance or immunoregulation of p53-related neoplastic events

A User-Centered Active Learning Approach for Appliance Recognition

Smart homes offer new possibilities for energy management. One key enabler of these systems is the ability to monitor energy consumption at the appliance level. Existing approaches rely mainly on data from aggregated smart meter readings, but lack sufficient accuracy to recognize several appliances. Conversely, smart outlets are a suitable alternative since they can provide accurate electrical readings on individual appliances. Previous approaches for appliance recognition based on smart outlets use passive machine learning, which are deficient in the flexibility and scalability to work with highly heterogeneous appliances in smart homes. In this paper, we propose a stream-based active learning approach, called K-Active-Neighbors (KAN), to address the problem of appliance recognition in smart homes. KAN is an interactive framework in which the user is asked to label signatures of recently used appliances. Differently from previous work, we consider the realistic case in which the user is not always available to participate in the labeling process. Therefore, the system simultaneously learns the signatures and also the user willingness to interact with the system, in order to optimize the learning process. We develop an Arduino-based smart outlet to test our approach. Results show that, compared to previous solutions, KAN achieves higher accuracy in up to 41% less time