Muscle Activity and User-Perceived Exertion During Immersive Virtual Reality Exergaming Incorporating an Adaptive Cable Resistance System

International Journal of Exercise Science 15(7): 261-275, 2022. The purpose of this exploratory study was to characterize muscle activation via surface electromyography (sEMG), user-perceived exertion, and enjoyment during a 30-minute session of immersive virtual reality (IVR) cable resistance exergaming. Ten healthy, college-aged males completed a signature 30-minute exergaming session using an IVR adaptive cable resistance system that incorporated six traditional compound exercises. Muscle activation (sEMG) was captured during the session with a wearable sEMG system. Rated of Perceived Exertion (RPE) and Physical Activity Enjoyment Scale (PACES) were recorded following the session. Pectoralis major showed the highest activation during chest press, deltoids showed the highest activation on overhead press, latissimus dorsi showed the highest activation during lat pulldown and row exercises, hamstrings were the most activated muscles during Romanian deadlift, and glutes showed the highest activity during squats. RPE and PACES mean scores were 14 (1) and 4.27 (0.38), respectively. IVR exergaming with resistance cable training provides an enjoyable experience and distracts practitioners from exertion while exercising at a high intensity. Results from this study suggest similar muscle activation responses compared to traditional resistance exercises as demonstrated with prior evidence. This novel form of exercise might have important repercussions for improving health outcomes among those who find it challenging to adhere to and enjoy exercise routines, as well as with little knowledge on how to progress in their resistance training. Further investigations are needed to explore long-term adaptations and to assess if IVR exergaming has additional benefits compared to traditional resistance training

Real-Time Cytotoxicity Assay for Rapid and Sensitive Detection of Ricin from Complex Matrices

BACKGROUND: In the context of a potential bioterrorist attack sensitive and fast detection of functionally active toxins such as ricin from complex matrices is necessary to be able to start timely countermeasures. One of the functional detection methods currently available for ricin is the endpoint cytotoxicity assay, which suffers from a number of technical deficits. METHODOLOGY/FINDINGS: This work describes a novel online cytotoxicity assay for the detection of active ricin and Ricinus communis agglutinin, that is based on a real-time cell electronic sensing system and impedance measurement. Characteristic growth parameters of Vero cells were monitored online and used as standardized viability control. Upon incubation with toxin the cell status and the cytotoxic effect were visualized using a characteristic cell index-time profile. For ricin, tested in concentrations of 0.06 ng/mL or above, a concentration-dependent decrease of cell index correlating with cytotoxicity was recorded between 3.5 h and 60 h. For ricin, sensitive detection was determined after 24 h, with an IC50 of 0.4 ng/mL (for agglutinin, an IC50 of 30 ng/mL was observed). Using functionally blocking antibodies, the specificity for ricin and agglutinin was shown. For detection from complex matrices, ricin was spiked into several food matrices, and an IC50 ranging from 5.6 to 200 ng/mL was observed. Additionally, the assay proved to be useful in detecting active ricin in environmental sample materials, as shown for organic fertilizer containing R. communis material. CONCLUSIONS/SIGNIFICANCE: The cell-electrode impedance measurement provides a sensitive online detection method for biologically active cytotoxins such as ricin. As the cell status is monitored online, the assay can be standardized more efficiently than previous approaches based on endpoint measurement. More importantly, the real-time cytotoxicity assay provides a fast and easy tool to detect active ricin in complex sample matrices

Pleistocene landscape entrenchment: a geomorphological mountain to foreland field case, the Las Tunas system, Argentina

The study of the Las Tunas River incisions, located in the eastern Andean foreland front (3320’ S in Argentina), provides new clues for the interpretation of deep piedmont entrenchments. Both the Las Tunas mountain catchment and its piedmont are strongly entrenched with maximal incision of over 100 m at the mountain front. Three main terrace levels are well exposed and are labelled T1, T2 and T3 from the youngest to the oldest. We combined geological and geomorphological field observations, kinematic GPS data, satellite data and aerial photos with geochronological 40 Ar/39 Ar and 10 Be analysis to provide a detailed description of terrace organization and a discussion of the evolution of the Las Tunas landscape. The surprisingly 10 Be constant concentrations in surface layers as deep as 1.5 m show that gently dipping alluvial surfaces can be continuously and deeply mixed. Our data show a first period of deposition (Mesones Fm) before 0.85 Myr (minimum T3 age), followed by deep erosion and a second sedimentation period (Las Tunas Fm) that includes a ca. 0.6 Myr ash deposit. T2 and T1 are inset in the Las Tunas Fm and were abandoned ca. 15–20 kyr ago. The similar ages for T2 and T1 show that post-20kyr entrenchment occurred very rapidly. Despite Quaternary deformation in the Las Tunas piedmont, terrace entrenchment is best explained by paleo-climatic changes. The terrace organization reveals that the erosion-sedimentation phases affected the entire system from the piedmont toe to 10 km upstream of the mountain front. Finally, contrary to the neighbouring more deeply incised Diamante River system, where late Quaternary piedmont uplift is more likely to have been a factor causing incision, the more stable Las Tunas system provides an incomplete geomorphological record of Pleistocene and Holocene climate variations. We suggest that climate variations are better recorded in uplifting piedmonts than in stable ones, where the magnitude of incision and sedimentation and the fact that they occur repeatedly at the same elevation can erase a large part of the record.Fil: Pepin, E.. Université de Toulouse. Geosciences Environnement Toulouse, OMP, UPS, CNRS, IRD; FranciaFil: Carrieter, S.. Université de Toulouse. Geosciences Environnement Toulouse, OMP, UPS, CNRS, IRD; FranciaFil: Hérail, G.. Université de Toulouse. Geosciences Environnement Toulouse, OMP, UPS, CNRS, IRD; FranciaFil: Regard, V.. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Advanced Mining Technology Center (AMTC); Chile. Universidad Andres Bello. Facultad de Ingeniería. Escuela de Ciencias de la Tierra; ChileFil: Charrier, R. . Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Advanced Mining Technology Center (AMTC); Chile. Universidad Andres Bello. Facultad de Ingeniería. Escuela de Ciencias de la Tierra; ChileFil: Farías, M.. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Advanced Mining Technology Center (AMTC); ChileFil: Garcia, Victor Hugo. Universidad Nacional de Río Negro. Instituto de Investigación en Paleobiología y Geología sede Alto Valle; Argentin