Short-duration Experiments Research Articles

A Simple, Rapid, and Effective Method for Tumor Xenotransplantation Analysis in Transparent Zebrafish Embryos.

In vivo studies of tumor behavior are a staple of cancer research; however, the use of mice presents significant challenges in cost and time. Here, we present larval zebrafish as a transplant model that has numerous advantages over murine models, including ease of handling, low expense, and short experimental duration. Moreover, the absence of an adaptive immune system during larval stages obviates the need to generate and use immunodeficient strains. While established protocols for xenotransplantation in zebrafish embryos exist, we present here an improved method involving embryo staging for faster transfer, survival analysis, and the use of flow cytometry to assess disease burden. Embryos are staged to facilitate rapid cell injection into the yolk of the larvae and cell marking to monitor the consistency of the injected cell bolus. After injection, embryo survival analysis is assessed up to 7 days post injection (dpi). Finally, disease burden is also assessed by marking transferred cells with a fluorescent protein and analysis by flow cytometry. Flow cytometry is enabled by a standardized method of preparing cell suspensions from zebrafish embryos, which could also be used in establishing the primary culture of zebrafish cells. In summary, the procedure described here allows a more rapid assessment of the behavior of tumor cells in vivo with larger numbers of animals per study arm and in a more cost-effective manner.

Feral frogs, native newts, and chemical cues: identifying threats from and management opportunities for invasive African Clawed Frogs in Washington state.

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents-including multiple parts of North America-due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa-which produce a powerful neurotoxin tetrodotoxin (TTX)-may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis.

Residual Effect of Compost and Biochar Amendment on Soil Chemical, Biological, and Physical Properties and Durum Wheat Response

The residual effect of compost and biochar amendment on soil properties and durum wheat response was evaluated under field conditions in a Mediterranean environment. The treatments compared in a randomized complete block experimental design with three replications were: mineral fertilizer (100 kg N ha−1), compost applied at the rate of 25 Mg ha−1, biochar applied at the rates of 10 and 30 Mg ha−1, unfertilized control. Wheat was the second crop included in a sorghum–wheat cropping system and did not receive fertilizer supply. A hierarchical statistical analysis was carried out to investigate how different treatments could impact the cropping system performance. The findings highlight the significant influence of soil properties, particularly total N, WEOC, and TOC, on wheat and protein yield. One year after the amendment and fertilizer application, compost and biochar significantly increased soil total organic carbon content. The highest soil water extractable organic carbon was found with the compost application (76.9 mg kg−1), whereas the lowest value (50 mg kg−1) was with the highest rate of biochar. Soil respiration rates and hydraulic properties were not affected by the investigated treatments. This behavior is probably related to the short experimental duration and to the silty clayey soil texture. Significant correlations were observed between bulk density and water content at pressure heads in the −20 and −100 cm range; this range accounts for the effect of soil macro and mesopores. Multiple linear regression analysis revealed strong predictive power for grain (R2_adj = 0.78; p < 0.001) and protein yield (R2_adj = 0.77; p < 0.001). The highest grain yield (3.36 Mg ha−1) was observed with compost, and the lowest (2.18 Mg ha−1) with biochar at a rate of 30 Mg ha−1. These findings lay the basis for understanding how different soil amendment management may impact soil quality and wheat performance, even in consideration of climate change.

Discovery and Characterization of Fluopipamine, a Putative Cellulose Synthase 1 Antagonist within Arabidopsis.

Herbicide-resistant weeds are increasingly a problem in crop fields when exposed to similar chemistry over time. To avoid future yield losses, identifying herbicidal chemistry needs to be accelerated. We screened 50,000 small molecules using a liquid-handling robot and light microscopy focusing on pre-emergent herbicides in the family of cellulose biosynthesis inhibitors. Through phenotypic, chemical, genetic, and in silico methods we uncovered 6-{[4-(2-fluorophenyl)-1-piperazinyl]methyl}-N-(2-methoxy-5-methylphenyl)-1,3,5-triazine-2,4-diamine (fluopipamine). Symptomologies support fluopipamine as a putative antagonist of cellulose synthase enzyme 1 (CESA1) from Arabidopsis (Arabidopsis thaliana). Ectopic lignification, inhibition of etiolation, phenotypes including loss of anisotropic cellular expansion, swollen roots, and live cell imaging link fluopipamine to cellulose biosynthesis inhibition. Radiolabeled glucose incorporation of cellulose decreased in short-duration experiments when seedlings were incubated in fluopipamine. To elucidate the mechanism, ethylmethanesulfonate mutagenized M2 seedlings were screened for fluopipamine resistance. Two loci of genetic resistance were linked to CESA1. In silico docking of fluopipamine, quinoxyphen, and flupoxam against various CESA1 mutations suggests that an alternative binding site at the interface between CESA proteins is necessary to preserve cellulose polymerization in compound presence. These data uncovered potential fundamental mechanisms of cellulose biosynthesis in plants along with feasible leads for herbicidal uses.

Soft Computing Model for Inverse Prediction of Surface Heat Flux from Temperature Responses in Short-Duration Heat Transfer Experiments

Abstract Aerodynamic experiments in high speed flow domain mainly rely on precise measurement transient surface temperatures and subsequent quantification of heat flux. These experiments are mainly simulated in high enthalpy short-duration facilities for which test flow duration are in the order of few milliseconds and the thermal loads resemble the nature of step/impulse. This study focuses on a specially designed fast-response coaxial surface junction thermal probe (CSTP) with capability of capturing transient temperature signals. The short-duration calibration experiments are realized to mimic the simulated flow conditions of high enthalpy test facilities. The classical one-dimensional heat conduction modelling has been used to deduce surface heat flux from the acquired temperature responses. It demonstrates a commendable accuracy of 2.5% when compared with known heat loads of calibration experiment. An advanced soft computing technique, the Adaptive Neuro-Fuzzy Inference System (ANFIS), is introduced for short-duration heat flux predictions. This methodology successfully recovers known (step or ramp) heat loads within a specific experimental time frame (0.2s). The results exhibit excellent agreement in prediction of trend and magnitude, carrying uncertainties of 3% for radiative and 5% for convective experiments. Consequently, the CSTP appears as a rapidly responsive transient heat flux sensor; for real-time short-duration experiments. The soft computing approach (ANFIS) offers an alternative means of heat flux estimation from temperature history irrespective of mode of heat transfer and nature of heat load, marked by its prediction accuracy, diminished mathematical intricacies, and reduced numerical requisites.

Potential and performance of anisotropic 19F NMR for the enantiomeric analysis of fluorinated chiral active pharmaceutical ingredients.

Controlling the enantiomeric purity of chiral drugs is of paramount importance in pharmaceutical chemistry. Isotropic 1H NMR spectroscopy involving chiral agents is a widely used method for discriminating enantiomers and quantifying their relative proportions. However, the relatively weak spectral separation of enantiomers (1H Δδiso(R, S)) in frequency units at low and moderate magnetic fields, as well as the lack of versatility of a majority of those agents with respect to different chemical functions, may limit the general use of this approach. In this article, we investigate the analytical potential of 19F NMR in anisotropic chiral media for the enantiomeric analysis of fluorinated active pharmaceutical ingredients (API) via two residual anisotropic NMR interactions: the chemical shift anisotropy (19F-RCSA) and dipolar coupling ((19F-19F)-RDC). Lyotropic chiral liquid crystals (CLC) based on poly-γ-benzyl-L-glutamate (PBLG) show an interesting versatility and adaptability to enantiodiscrimination as illustrated for two chiral drugs, Flurbiprofen® (FLU) and Efavirenz® (EFA), which have very different chemical functions. The approach has been tested on a routine 300 MHz NMR spectrometer equipped with a standard probe (5 mm BBFO probe) in a high-throughput context (i.e., ≈10 s of NMR experiments) while the performance for enantiomeric excess (ee) measurement is evaluated in terms of trueness and precision. The limits of detection (LOD) determined were 0.17 and 0.16 μmol ml-1 for FLU and EFA, respectively, allow working in dilute conditions even with such a short experimental duration. The enantiodiscrimination capabilities are also discussed with respect to experimental features such as CLC composition and temperature.

Precipitation change affects forest soil carbon inputs and pools: A global meta-analysis

The impacts of precipitation change on forest carbon (C) storage will have global consequences, as forests play a major role in sequestering anthropogenic CO2. Although forest soils are one of the largest terrestrial C pools, there is great uncertainty around the response of forest soil organic carbon (SOC) to precipitation change, which limits our ability to predict future forest C storage. To address this, we conducted a meta-analysis to determine the effect of drought and irrigation experiments on SOC pools, plant C inputs and the soil environment based on 161 studies across 139 forest sites worldwide. Overall, forest SOC content was not affected by precipitation change, but both drought and irrigation altered plant C inputs and soil properties associated with SOC formation and storage. Drought may enhance SOC stability by altering soil aggregate fractions, but the effect of irrigation on SOC fractions remains unexplored. The apparent insensitivity of SOC to precipitation change can be explained by the short duration of most experiments and by biome-specific responses of C inputs and pools to drought or irrigation. Importantly, we demonstrate that SOC content is more likely to decline under irrigation at drier temperate sites, but that dry forests are currently underrepresented across experimental studies. Thus, our meta-analysis advances research into the impacts of precipitation change in forests by revealing important differences among forest biomes, which are likely linked to plant adaptation to extant conditions. We further demonstrate important knowledge gaps around how precipitation change will affect SOC stability, as too few studies currently consider distinct soil C pools. To accurately predict future SOC storage in forests, there is an urgent need for coordinated studies of different soil C pools and fractions across existing sites, as well as new experiments in underrepresented forest types.

Microbial necromass under global change and implications for soil organic matter.

Microbial necromass is an important source and component of soil organic matter (SOM), especially within the most stable pools. Global change factors such as anthropogenic nitrogen (N), phosphorus (P), and potassium (K) inputs, climate warming, elevated atmospheric carbon dioxide (eCO2 ), and periodic precipitation reduction (drought) strongly affect soil microorganisms and consequently, influence microbial necromass formation. The impacts of these global change factors on microbial necromass are poorly understood despite their critical role in the cycling and sequestration of soil carbon (C) and nutrients. Here, we conducted a meta-analysis to reveal general patterns of the effects of nutrient addition, warming, eCO2 , and drought on amino sugars (biomarkers of microbial necromass) in soils under croplands, forests, and grasslands. Nitrogen addition combined with P and K increased the content of fungal (+21%), bacterial (+22%), and total amino sugars (+9%), consequently leading to increased SOM formation. Nitrogen addition alone increased solely bacterial necromass (+10%) because the decrease of N limitation stimulated bacterial more than fungal growth. Warming increased bacterial necromass, because bacteria have competitive advantages at high temperatures compared to fungi. Other global change factors (P and NP addition, eCO2 , and drought) had minor effects on microbial necromass because of: (i) compensation of the impacts by opposite processes, and (ii) the short duration of experiments compared to the slow microbial necromass turnover. Future studies should focus on: (i) the stronger response of bacterial necromass to N addition and warming compared to that of fungi, and (ii) the increased microbial necromass contribution to SOM accumulation and stability under NPK fertilization, and thereby for negative feedback to climate warming.

Reliable, Fast and Stable Contrast Response Function Estimation.

A study was conducted to determine stable cortical contrast response functions (CRFs) accurately and repeatedly in the shortest possible experimentation time. The method consisted of searching for experimental temporal aspects (number and duration of trials and number and distribution of contrasts used) with a model based on inhomogeneous Poisson spike trains to varying contrast levels. The set of values providing both short experimental duration and maximizing fit of the CRFs were saved, and then tested on cats’ visual cortical neurons. Our analysis revealed that 4 sets of parameters with less or equal to 6 experimental visual contrasts satisfied our premise of obtaining good CRFs’ performance in a short recording period, in which the number of trials seems to be the experimental condition that stabilizes the fit.

Rotational Components of Normal Modes Measured at a Natural Sandstone Tower (Kane Springs Canyon, Utah, U.S.A.)

AbstractModal analysis of freestanding rock formations is crucial for evaluating their vibrational response to external stimuli, aiding accurate assessment of associated geohazards. Whereas conventional seismometers can be used to measure the translational components of normal modes, recent advances in rotational seismometer technology now allow direct measurement of the rotational components. We deployed a portable, three-component rotational seismometer for a short-duration experiment on a 36 m high sandstone tower located near Moab, Utah, in addition to conducting modal analysis using conventional seismic data and numerical modeling. Spectral analysis of rotation rate data resolved the first three natural frequencies of the tower (2.1, 3.1, and 5.9 Hz), and polarization analysis revealed the orientations of the rotation axes. Modal rotations were the strongest for the first two eigenmodes, which are mutually perpendicular, full-height bending modes with horizontal axes of rotation. The third mode is torsional with rotation about a subvertical axis. Measured natural frequencies and the orientations of displacements and rotation axes match our numerical models closely for these first three modes. In situ measurements of modal rotations are valuable at remote field sites with limited access, and contribute to an improved understanding of modal deformation, material properties, and landform response to vibration stimuli.

Errors Incurred in Local Convective Heat Transfer Coefficients Obtained through Transient One-Dimensional Semi-Infinite Conduction Modeling: A Computational Heat Transfer Study

In typical turbulent flow problems, detailed heat transfer coefficient (h) maps obtained through short-duration experiments are based on inverse heat transfer methods that take the wall temperatures measured via liquid crystals or infrared thermography as input, and an error minimization routine is adopted to determine the best value of h that satisfies the wall temperature temporal evolution under a certain change in fluid temperature. A common practice involves modeling the solid as a one-dimensional semi-infinite medium by selecting the solid material that has low thermal conductivity and low thermal diffusivity. However, in certain flow scenarios, the neglection of the lateral heat diffusion may lead to significant errors in the deduced h values. It is imperative to understand the reasons behind large errors that may be incurred by using the 1D heat conduction assumption in order to accurately determine high-resolution h maps for better heat exchanger designs in a wide range of thermal management applications. This paper presents a computational heat transfer study on different jet impingement scenarios to demonstrate the errors incurred in the determination of h when calculated under the assumption of one-dimensional (1-d) heat conduction into a solid. To this end, three different cases are studied: (a) single jet, (b) array jet (theoretical distribution), (c) array jet (experimental distribution), along with three different mainstream temperature evolution profiles representing step change, moderately fast transient and slow transient nature of flow driving the heat transfer in the solid. A known distribution of heat transfer coefficient (“true h”) for each of the three cases is considered, and three-dimensional transient heat diffusion equations were solved to populate temperatures of each node in the solid at every time step. It is found that stagnation zones’ h1d calculations were lower than the “true h” while the low heat transfer zones exhibited significantly higher h1d compared to the “true h”. For the array jet (experimental distribution) case, it was observed that errors can be as high as 10% in certain low heat transfer zones. Different data reduction procedures, configurations, and conditions explored in this study indicate that a suitable balance can be achieved if shorter time durations in transient experiments are used as a reference for tracking in h1d calculations to keep the deviations from the “true h” low.

The impact of no‐till crop rotation on dryland soil properties and crop yields

AbstractInformation on the effect of no‐till crop rotation on a broad range of soil properties and long‐term crop yields is needed to evaluate its benefits on ecosystem services compared with monocropping. The objective of this study was to examine the effects of no‐till crop rotation (barley [Hordeum vulgare L.]/spring wheat [Triticum aestivum L.]–pea [Pisum sativum L.]) and monocropping [continuous barley/spring wheat] on 66 dryland soil physical, chemical, biological, and biochemical properties and long‐term crop yields at two dryland farm sites (14‐ and 36‐yr old) in the northern Great Plains. Soil samples collected to a depth of 15 cm in April 2019 were analyzed for soil properties and crop yields determined. At the long‐term site, crop rotation increased 11 properties, but reduced 16 of 66 soil properties compared with monocropping. At the short‐time site, crop rotation increased 6 properties, but reduced 13 of 66 soil properties compared with monocropping. Longer duration experiments showed more differences in soil properties due to crop rotation than shorter duration experiments. Spring wheat and barley yields were greater following pea than following spring wheat or barley during years with normal or above‐average precipitation at both sites. Pea yield in the crop rotation was also greater during these years. Barley/spring wheat–pea rotation can enhance some soil properties and dryland crop yields compared with continuous barley/spring wheat during wet years in the semiarid region of the northern Great Plains.

Adaptation of stimulation duration to enhance auditory response in fNIRS block design

Functional near-infrared spectroscopy (fNIRS) is an increasingly popular method in hearing research. However, few studies have considered efficient stimulation parameters for the auditory experimental design of fNIRS. The objectives of our study are (1) to identify the most effective paradigm for the stimulation blocks with increasing duration (8s, 10s, 15s, 20s) in terms of response amplitude, i.e., the most-efficient stimulation duration; (2) to assess the linearity/nonlinearity of the hemodynamic responses with respect to increasing block durations; and (3) to generalize results to more ecological environmental stimuli. We found that cortical activity is augmented following the increments in stimulation durations and reaches a plateau after about 15s of stimulation. The linearity analysis showed that this augmentation due to stimulation duration is not linear in the auditory cortex, non-linearity being more pronounced for shorter durations (15s and 20s). The 15s block duration that we propose as the most suitable precludes signal saturation and is associated with a high response amplitude and a relatively short total experimental duration. Moreover, the distribution of stimuli among the 15s blocks, which is the most effective for white noise stimulation, also provides a comparably strong response for environmental sounds. The sum of these findings suggests that 15s stimulation duration used in the appropriate experimental setup allows researchers to acquire optimal fNIRS signal quality.

Soil warming and straw return impacts on winter wheat phenology, photosynthesis, root growth, and grain yield in the North China Plain

Soil temperature rise caused by global warming is one of the most serious threats to crop physiology and production. Straw return is considered as a potential strategy to improve soil health and agricultural productivity. However, little is known about their interactive effects on wheat growth and production, which limits the development of strategies and technological innovations for future food security. Therefore, in the two wheat seasons from 2018 to 2020, with or without straw return, the heating cable was laid at a depth of 20 cm to increase the soil temperature by 3.8 ℃, and the phenology, photosynthesis, root growth, and grain yield of winter wheat were studied. Soil warming advanced the anthesis date by one week and promoted pre-anthesis wheat growth and dry matter transportation. However, soil warming decreased post-anthesis duration, leaf area index, SPAD, net photosynthesis, and spectral vegetation indexes. Therefore, post-anthesis dry matter accumulation and grain filling were inhibited, lowering the 1000-grain weight and harvest index. Furthermore, the post-anthesis root weight, length, surface area densities and root to shoot ratio were also decreased under soil warming. Finally, soil warming reduced the grain yield by 35.2% in the dry 2018–2019 year. However, the wheat growth characteristics were considerably higher and no difference in grain yield was detected among treatments in the wet 2019–2020 season, indicating that increased precipitation may offset the adverse effect of soil warming on wheat yield. Straw return increased aboveground biomass, but had no effect on wheat yield, probably because the positive effects were limited in the short experimental duration. The findings suggested that soil warming would promote pre-anthesis wheat growth but accelerate post-anthesis wheat senescence, affect dry matter transportation and accumulation, eventually reducing wheat yield in the NCP, especially under dry condition.

Pig-to-human kidney transplantation using brain-dead donors as recipients: One giant leap, or only one small step for transplantkind?

Pig kidney xenotransplantation is increasingly regarded as a realistic solution to the current shortage of human organ donors for patients with end-stage organ failure. Recently, the news of three pig-to-human transplantation cases has awakened public interest. Notably, the case by the Alabama team reported detailed and important findings for the xenotransplantation field. Using a genetically modified pig, two porcine kidneys were transplanted into a brain-dead recipient. They applied several approaches established in the preclinical NHP study, including gene-edited pig kidney graft and preoperative laboratory inspection such as crossmatching and infection screening. The pig-to-human kidney xenotransplantation had no unexpected events during surgery or evidence of hyperacute rejection. Unfortunately, the grafts did not work appropriately, and the study had to be terminated due to the decompensation of the recipient. While this study demonstrated the outstanding achievement in this research area, it also revealed remaining gaps to move xenotransplantation to the clinic. While brain-dead human recipients could reinforce the compatibility achievements of gene-edited pigs in NHP, their pro-inflammatory and pro-coagulant environment, in combination with short-duration of experiments will limit the assessment of kidney function, infection and rejection risk post-transplant, in particular antibody-mediated rejection. The use of successful immunosuppressive protocols of non-human primates xenotransplant experiments including anti-CD154 antibody will be critical to maximize the success in the first in-human trials.

Acid stimulation in carbonates: Microfluidics allows accurate measurement of acidic fluid reaction rates in carbonate rocks by quantifying the produced CO2 gas

Acid stimulation has been the interest of researchers for many years due to its high efficiency in improving the near-wellbore permeability caused by the formation damage. The productivity enhancement stems from the creation of extremely conductive pathways called wormholes as a result of the interaction between the acidic fluid and carbonate rocks. Therefore, it is crucial to quantify the reaction rate between the acidic fluid and the carbonate rocks to ensure achieving the desired outcome. In this study, we will utilize microfluidics technology to accurately calculate the reaction rate of hydrochloric acid (HCl) with carbonate rocks under flow conditions by quantifying the produced CO2 gas. This approach, unlike conventional methods, allows for accurate measurement, short experiment duration, reduction of chemical usage, and power consumption. In this study, the reaction rate of the HCl with Silurian dolomite was successfully measured by quantifying the produced CO2 gas over time and found to be a surface reaction limited regime. Additionally, the reaction rate of HCl and Indiana limestone was also measured for various HCl concentrations and found to be a mass transfer limit regime. The findings of this study allow for accurate reaction rate measurement of reactive fluid with carbonate rocks which will ultimately improve the design and prediction of carbonate acidizing process. Furthermore, the proposed method enables direct observation of the multi-physics process of porous media flow through a geo-material by facilitating the visualization and understanding of rock-fluid interactions. Lastly, the cell presented here offers a promising technique to investigate a real reservoir rock for fast and reliable laboratory tests. Multiple fluid-solid chemical reactions can be assessed, allowing direct observations of the flow and transport in porous and fractured media.

An Ultra-Fast TSP on a CNT Heating Layer for Unsteady Temperature and Heat Flux Measurements in Subsonic Flows.

In this paper, the authors demonstrate the application of a modified Ru(phen)-based temperature-sensitive paint which was originally developed for the evaluation of unsteady aero-thermodynamic phenomena in high Mach number but short duration experiments. In the present work, the modified TSP with a temperature sensitivity of up to −5.6%/K was applied in a low Mach number long-duration test case in a low-pressure environment. For the demonstration of the paint’s performance, a flat plate with a mounted cylinder was set up in the High-Speed Cascade Wind Tunnel (HGK). The test case was designed to generate vortex shedding frequencies up to 4300 Hz which were sampled using a high-speed camera at 40 kHz frame rate to resolve unsteady surface temperature fields for potential heat-transfer estimations. The experiments were carried out at reduced ambient pressure of = 13.8 kPa for three inflow Mach numbers being . In order to enable the resolution of very low temperature fluctuations down to the noise floor of K with high spatial and temporal resolution, the flat plate model was equipped with a sprayable carbon nanotube (CNT) heating layer. This constellation, together with the thermal sensors incorporated in the model, allowed for the calculation of a quasi-heat-transfer coefficient from the surface temperature fields. Besides the results of the experiments, the paper highlights the properties of the modified TSP as well as the methodology.

The Effect of Face Masks on Physiological Data and the Classification of Rehabilitation Walking.

Gait analysis and the assessment of rehabilitation exercises are important processes that occur during fitness level monitoring and the treatment of neurological disorders. This paper presents the possibility of using oximetric, heart rate (HR), accelerometric, and global navigation satellite systems (GNSSs) to analyse signals recorded during uphill and downhill walking without and with a face mask to find its influence on physiological functions during selected walking patterns. The experimental dataset includes 86 signal segments acquired under different conditions. The proposed methodology is based on signal analysis in both the time and frequency domains. The results indicate that face mask use has a minimal effect on blood oxygen concentration and heart rate, with the average mean changes of these parameters being less than 2%. The support vector machine, a Bayesian method, the k -nearest neighbour method, and a two-layer neural network showed very good separation abilities and successfully classified different walking patterns only in the case when the effect of face mask wearing was not included in the classification process. Our methodology suggests that artificial intelligence and machine learning tools are efficient methods for the assessment of motion patterns in different motion conditions and that face masks have a negligible effect for short-duration experiments.

Responses of plant productivity and carbon fluxes to short-term experimental manipulations of climate change and species loss in a Mongolian grassland

We examined the responses of primary productivity and carbon fluxes (net ecosystem productivity, gross primary productivity, and ecosystem respiration) to climate (using open top chambers and electric heating) and species richness manipulations (by non-random species removal) in Mongolian grasslands. We observed a decreasing tendency in plant productivity and carbon flux due to warming, which would be mitigated by watering. This suggests that decrease in soil moisture due to concomitantly increasing evaporation and rain interception by open top chambers rather than increasing temperature might explain the decreasing tendency of productivity and carbon fluxes due to climate manipulations. Plant productivity was reduced only in the plots with the lowest species richness, and carbon fluxes did not change according to non-random species richness manipulations, suggesting that productivity and carbon fluxes are relatively robust to species loss. Our results would be associated with the compensation of the loss of perennial grasses and sedges by annual forbs. Such a compensatory mechanism might have caused negligible interaction effects of climate and species richness manipulations on productivity and carbon fluxes. Because our result was limited by a short experimental duration, in future studies, the long-term functional consequences of climate warming and species loss should be fully examined.

NASA's Ground-Based Microgravity Simulation Facility.

Since opportunities to conduct experiments in space are scarce, various microgravity simulators and analogs have been widely used in space biology ground studies. Even though microgravity simulators do not produce all of the biological effects observed in the true microgravity environment, they provide alternative test platforms that are effective, affordable, and readily available to facilitate microgravity research. The Microgravity Simulation Support Facility (MSSF) at the National Aeronautics and Space Administration (NASA) John F. Kennedy Space Center (KSC) has been established for conducting short duration experiments, typically less than 1 month, utilizing a variety of microgravity simulation devices for research at different gravity levels. The simulators include, but are not limited to, 2D Clinostats, 3D Clinostats, Random Positioning Machines, and Rotating Wall Vessels. In this chapter, we will discuss current MSSF capabilities, development concepts, and the physical characteristics of these microgravity simulators.