Development of a Quantitative Evaluation Tool of Cognitive Workload in Field Studies Through Eye Tracking.

Eye tracking is mainly employed as mean of tracking visual attention of an observer/operator. Still, eye tracking is also capable of recording a wider variety of data such as traces of mental workload. Pupil diameter have been validated as such measure. Most of the studies that have validated this are in laboratory conditions, where the perceived luminance (measured in candela per square meter) can be controlled. Luminance affects the pupil diameter as well; this means if the pupil diameter varies for an operator/observer in field conditions it cannot be accurately determined if the change in the pupil diameter is due to mental workload alone. Although there are some studies, which have attempted to simultaneously account for the contribution of the change in pupil diameter due to luminance and mental workload, not many have attempted to account for this in field conditions for safety-critical systems such as a helicopter or a maritime ship bridge. In this study as a first step, we define a method to measure luminance while tracking the gaze point. We will record eye-tracking data simultaneously recording the video feed of the field of view of the operator/observer. We will use the video feed to estimate the luminous flux from the point of view of the subject. We will be collecting this data from a helicopter pilot and his co-pilot during an actual operation (e.g. transportation of personnel and carrying a payload for an electrical power provider company in Norway or Sweden). We will also be collecting data from a navigator and his first officer in a high-speed marine craft of the Norwegian navy. We will also be collecting subjective data using paper-based tools such as NASA-TLX in addition to a conventional video recording of the scene of activity and handwritten notes of observation for validation purposes. We will also capture mental workload data from a few other objective sources such as heart rate variability (ECG). We expect to clearly define an approach to separately account for the effect of mental workload independent of the impact of changing light conditions in field situations for safety-critical systems. This includes a mathematical model that we innovate based on other mathematical models that are already available in the literature

A novel approach to identify antigens recognized by CD4 T cells using complement-opsonized bacteria expressing a cDNA library

In patients with hematological malignancies receiving HLA-matched stem cell transplantation, T cells specific for minor histocompatibility antigens play a major role in graft rejection, induction of graft-versus-host disease and beneficial graft-versus-leukemia reactivity. Several human minor histocompatibility antigens recognized by T cells have been identified, but only two are presented by HLA class II molecules. In search of an efficient approach to identify antigenic peptides processed through the HLA class II pathway, we constructed a cDNA library in bacteria that were induced to express proteins. Bacteria were opsonized with complement to enforce receptor-mediated uptake by Epstein - Barr virus immortalized B cells that were subsequently used as antigen-presenting cells. This approach was validated with an HLA class II-restricted antigen encoded by gene DBY. We were able to identify bacteria expressing DBY diluted into a 300-fold excess of bacteria expressing a nonrelevant gene. Screening of a bacterial library using a DBY-specific CD4 T cell clone resulted in the isolation of several DBY cDNAs. We propose this strategy for a rapid identification of HLA class II-restricted antigenic peptides recognized by CD4 T cells