Pen-type electrodermal activity sensing system for stress detection based on likelihood ratios

Master of ScienceDepartment of Electrical and Computer EngineeringSteven WarrenPsychological stress experienced during academic testing is known to be a significant performance factor for some students. While a student may be able to recognize and self-report stress experienced during an exam, unobtrusive tools to track stress in real time (and in association with specific test problems) are lacking. This effort pursued the design and initial assessment of an electrodermal activity (EDA) sensor - essentially a sweat sensor - mounted to a pen/pencil 'trainer:' a holder into which a pen/pencil is inserted that can help a person learn how to properly grip a writing instrument. This small assembly was held in the hand of a given subject during early human subject experiments and can be used for follow-on, mock test-taking scenarios. Data were acquired with this handheld device for 37 subjects (Kansas State University Internal Review Board Protocol #9864) while they each viewed approximately 30 minutes of emotion-evoking videos. Data collected by the EDA sensor were processed with an EDA signal processing app, which calculated and stored parameters associated with significant phasic EDA peaks. These peak data were then evaluated by a hypothesis driven stress-detection test that employed an approach using likelihood ratios for the ‘relaxed’ and ‘stressed’ groups. For these initial, motion-free testing scenarios, this pen-type EDA sensing system was able to discern which phasic responses were associated with ‘relaxed’ versus ‘stressed’ responses with 85% accuracy, where subject self-assessments of perceived stress levels were used to establish ground truth

Influence of advective bio-irrigation on carbon and nitrogen cycling in sandy sediments

In sandy sediments, the burrow ventilation activity of benthic macrofauna can generate substantial advective flows within the sediment surrounding their burrows. Here we investigated the effects of such advective bio-irrigation on carbon and nitrogen cycling in sandy sediments. To this end, we combined a range of complementary experimental and modelling approaches in a microcosm study of the lugworm Arenicola marina (Polychaeta: Annelida). Bio-irrigation rates were determined using uranine as a tracer, while benthic fluxes of oxygen (O2), total carbon dioxide (TCO2), dissolved inorganic nitrogen (NH4+, ΣNO2− + NO3−) and dinitrogen (N2) were measured in closed-core incubations containing lugworms acclimatized for a relatively short (2 d) and long (3 wk) duration. The fluxes induced by A. marina were compared to those induced by mechanical mimics that simulate the flow pattern induced by the lugworm. These mechanical mimics proved a useful tool to simulate the effect of lugworm irrigation on sediment biogeochemistry. Subsequently, reactive transport model simulations were performed to check the consistency of the measured fluxes and rates, and to construct closed mass balances for sedimentary nitrogen. This reactive transport model successfully captured the essential features of the nitrogen cycling within the sediment. Advective irrigation by both lugworm and mechanical mimics significantly stimulated the sediments O2 consumption, organic matter mineralization rate (TCO2 release), and denitrification rate (N2 production). While sedimentary O2 consumption was directly correlated to advective input of O2, increasing irrigation rates increased the importance of coupled nitrification-denitrification over the external input of nitrate from the overlying water

Understanding CD4+ T cells in autoimmune bullous diseases

Autoimmune bullous diseases (AIBDs) are a group of life-threatening blistering diseases caused by autoantibodies that target proteins in the skin and mucosa. Autoantibodies are the most important mediator in the pathogenesis of AIBDs, and various immune mechanisms contribute to the production of these pathogenic autoantibodies. Recently, significant progress has been made in understanding how CD4+ T cells drive autoantibody production in these diseases. Here, we review the critical role of CD4+ T cells in the production of pathogenic autoantibodies for the initiation and perpetuation of humoral response in AIBDs. To gain an in-depth understanding of CD4+ T-cell pathogenicity, antigen specificity, and mechanisms of immune tolerance, this review covers comprehensive mouse and human studies of pemphigus and bullous pemphigoid. Further exploration of pathogenic CD4+ T cells will potentially provide immune targets for improved treatment of AIBDs

Eficacia antiincrustante de una formulación de pintura de reducción controlada con acetofenona

Biofouling is an inevitable problem that occurs continually on marine fishing vessels and other small crafts. The nature of the antifouling (AF) coatings used to prevent biofouling on these small vessels is of great environmental concern. Therefore, the efficacy of a non-toxic AF candidate, acetophenone, was evaluated in preliminary laboratory assays using marine bacteria, diatom and Ulva spores. At a low concentration of 100 μg cm–2 of acetophenone, spore attachment of a green fouling alga was significantly reduced (p < 0.01). Similarly, 40% acetophenone coatings significantly inhibited diatom attachment. This new non-toxic AF agent was incorporated into controlled depletion paint (CDP). Fouling coverage (%), biomass, and fouling resistance (%) were estimated. On CDP coatings made with acetophenone (40%), a significant decrease in fouling biomass was estimated (p < 0.01).El biofouling es un problema inevitable que ocurre continuamente en los buques de pesca marina y en las pequeñas embarcaciones. La naturaleza de los recubrimientos antiincrustantes (AF) usados para prevenir el bioincrustado en estos pequeños buques tiene gran preocupación ambiental. Por lo tanto, la eficacia de un candidato AF no tóxico, la acetofenona, se evaluó en ensayos preliminares de laboratorio usando bacterias marinas, diatomeas y esporas de Ulva. A una concentración baja de 100 μg cm–2 de acetofenona, la adherencia de esporas de una alga incrustante verde se redujo significativamente (p < 0.01). Del mismo modo, el revestimiento de acetofenona a un nivel del 40% inhibieró significativamente la adherencia de diatomeas. Además, esta nueva acetofenona AF no tóxica se incorporó a la pintura de reducción controlada (CDP). La cobertura de las incrustaciones (%), la biomasa y la resistencia a la incrustación (%) fueron estimadas. En recubrimientos de CDP donde se incorporó la acetofenona (40%), se estimó una disminución significativa de la biomasa incrustante (p < 0.01)

Implementation of a Vector-based Tracking Loop Receiver in a Pseudolite Navigation System

We propose a vector tracking loop (VTL) algorithm for an asynchronous pseudolite navigation system. It was implemented in a software receiver and experiments in an indoor navigation system were conducted. Test results show that the VTL successfully tracks signals against the near–far problem, one of the major limitations in pseudolite navigation systems, and could improve positioning availability by extending pseudolite navigation coverage

Establishment of feeder-free culture system for human induced pluripotent stem cell on DAS nanocrystalline graphene

The maintenance of undifferentiated human pluripotent stem cells (hPSC) under xeno-free condition requires the use of human feeder cells or extracellular matrix (ECM) coating. However, human-derived sources may cause human pathogen contamination by viral or non-viral agents to the patients. Here we demonstrate feeder-free and xeno-free culture system for hPSC expansion using diffusion assisted synthesis-grown nanocrystalline graphene (DAS-NG), a synthetic non-biological nanomaterial which completely rule out the concern of human pathogen contamination. DAS-NG exhibited advanced biocompatibilities including surface nanoroughness, oxygen containing functional groups and hydrophilicity. hPSC cultured on DAS-NG could maintain pluripotency in vitro and in vivo, and especially cell adhesion-related gene expression profile was comparable to those of cultured on feeders, while hPSC cultured without DAS-NG differentiated spontaneously with high expression of somatic cell-enriched adhesion genes. This feeder-free and xeno-free culture method using DAS-NG will facilitate the generation of clinical-grade hPSC.ope

Critical role of next-nearest-neighbor interlayer interaction in magnetic behavior of magnetic/nonmagnetic multilayers

We report magnetoresistance data in magnetic semiconductor multilayers, which exhibit a clear step-wise behavior as a function of external field. We attribute this highly non-trivial step-wise behavior to next-nearest-neighbor interlayer exchange coupling. Our microscopic calculation suggests that this next-nearest-neighbor coupling can be as large as 24% of the nearest-neighbor coupling. It is argued that such unusually long-range interaction is made possible by the quasi-one-dimensional nature of the system and by the long Fermi wavelength characteristic of magnetic semiconductors