A Method to Estimate Horse Speed per Stride from One IMU with a Machine Learning Method.

With the emergence of numerical sensors in sports, there is an increasing need for tools and methods to compute objective motion parameters with great accuracy. In particular, inertial measurement units are increasingly used in the clinical domain or the sports one to estimate spatiotemporal parameters. The purpose of the present study was to develop a model that can be included in a smart device in order to estimate the horse speed per stride from accelerometric and gyroscopic data without the use of a global positioning system, enabling the use of such a tool in both indoor and outdoor conditions. The accuracy of two speed calculation methods was compared: one signal based and one machine learning model. Those two methods allowed the calculation of speed from accelerometric and gyroscopic data without any other external input. For this purpose, data were collected under various speeds on straight lines and curved paths. Two reference systems were used to measure the speed in order to have a reference speed value to compare each tested model and estimate their accuracy. Those models were compared according to three different criteria: the percentage of error above 0.6 m/s, the RMSE, and the Bland and Altman limit of agreement. The machine learning method outperformed its competitor by giving the lowest value for all three criteria. The main contribution of this work is that it is the first method that gives an accurate speed per stride for horses without being coupled with a global positioning system or a magnetometer. No similar study performed on horses exists to compare our work with, so the presented model is compared to existing models for human walking. Moreover, this tool can be extended to other equestrian sports, as well as bipedal locomotion as long as consistent data are provided to train the machine learning model. The machine learning model's accurate results can be explained by the large database built to train the model and the innovative way of slicing stride data before using them as an input for the model.

Kinetics of substrate inhibition of periplasmic nitrate reductase.

Periplasmic nitrate reductase catalyzes the reduction of nitrate into nitrite using a mononuclear molybdenum cofactor that has nearly the same structure in all enzymes of the DMSO reductase family. In previous electrochemical investigations, we found that the enzyme exists in several inactive states, some of which may have been previously isolated and mistaken for catalytic intermediates. In particular, the enzyme slowly and reversibly inactivates when exposed to high concentrations of nitrate. Here, we study the kinetics of substrate inhibition and its dependence on electrode potential and substrate concentration to learn about the properties of the active and inactive forms of the enzyme. We conclude that the substrate-inhibited enzyme never significantly accumulates in the EPR-active Mo(+V) state. This conclusion is relevant to spectroscopic investigations where attempts are made to trap a Mo(+V) catalytic intermediate using high concentrations of nitrate.

Reductive activation in periplasmic nitrate reductase involves chemical modifications of the Mo-cofactor beyond the first coordination sphere of the metal ion.

In Rhodobacter sphaeroides periplasmic nitrate reductase NapAB, the major Mo(V) form (the "high g" species) in air-purified samples is inactive and requires reduction to irreversibly convert into a catalytically competent form (Fourmond et al., J. Phys. Chem., 2008). In the present work, we study the kinetics of the activation process by combining EPR spectroscopy and direct electrochemistry. Upon reduction, the Mo (V) "high g" resting EPR signal slowly decays while the other redox centers of the protein are rapidly reduced, which we interpret as a slow and gated (or coupled) intramolecular electron transfer between the [4Fe-4S] center and the Mo cofactor in the inactive enzyme. Besides, we detect spin-spin interactions between the Mo(V) ion and the [4Fe-4S](1+) cluster which are modified upon activation of the enzyme, while the EPR signatures associated to the Mo cofactor remain almost unchanged. This shows that the activation process, which modifies the exchange coupling pathway between the Mo and the [4Fe-4S](1+) centers, occurs further away than in the first coordination sphere of the Mo ion. Relying on structural data and studies on Mo-pyranopterin and models, we propose a molecular mechanism of activation which involves the pyranopterin moiety of the molybdenum cofactor that is proximal to the [4Fe-4S] cluster. The mechanism implies both the cyclization of the pyran ring and the reduction of the oxidized pterin to give the competent tricyclic tetrahydropyranopterin form.

Evidence of IL-17, IP-10, and IL-10 involvement in multiple-organ dysfunction and IL-17 pathway in acute renal failure associated to Plasmodium falciparum malaria.

BACKGROUND: Plasmodium falciparum malaria in India is characterized by high rates of severe disease, with multiple organ dysfunction (MOD)-mainly associated with acute renal failure (ARF)-and increased mortality. The objective of this study is to identify cytokine signatures differentiating severe malaria patients with MOD, cerebral malaria (CM), and cerebral malaria with MOD (CM-MOD) in India. We have previously shown that two cytokines clusters differentiated CM from mild malaria in Maharashtra. Hence, we also aimed to determine if these cytokines could discriminate malaria subphenotypes in Odisha. METHODS: P. falciparum malaria patients from the SCB Medical College Cuttack in the Odisha state in India were enrolled along with three sets of controls: healthy individuals, patients with sepsis and encephalitis (n = 222). We determined plasma concentrations of pro- and anti-inflammatory cytokines and chemokines for all individuals using a multiplex assay. We then used an ensemble of statistical analytical methods to ascertain whether particular sets of cytokines/chemokines were predictors of severity or signatures of a disease category. RESULTS: Of the 26 cytokines/chemokines tested, 19 increased significantly during malaria and clearly distinguished malaria patients from controls, as well as sepsis and encephalitis patients. High amounts of IL-17, IP-10, and IL-10 predicted MOD, decreased IL-17 and MIP-1α segregated CM-MOD from MOD, and increased IL-12p40 differentiated CM from CM-MOD. Most severe malaria patients with ARF exhibited high levels of IL-17. CONCLUSION: We report distinct differences in cytokine production correlating with malarial disease severity in Odisha and Maharashtra populations in India. We show that CM, CM-MOD and MOD are clearly distinct malaria-associated pathologies. High amounts of IL-17, IP-10, and IL-10 were predictors of MOD; decreased IL-17 and MIP-1α separated CM-MOD from MOD; and increased IL-12p40 differentiated CM from CM-MOD. Data also suggest that the IL-17 pathway may contribute to malaria pathogenesis via different regulatory mechanisms and may represent an interesting target to mitigate the pathological processes in malaria-associated ARF.

Acoustic imaging with spherical microphone array and Kriging.

Acoustic imaging can be performed using a spherical microphone array (SMA) and conventional beamforming (CBF) or spherical harmonic beamforming (SHB). At low frequencies, the mainlobe width depends on the SMA radius for CBF and on the order of the spherical harmonics expansion for SHB, which is related to the number of microphones. In this letter, Kriging is used to virtually increase the SMA radius and/or the number of microphones. Numerical and experimental investigations show the effectiveness of Kriging to reduce the mainlobe width and thus improve the acoustic images obtained with a SMA and CBF or SHB.

The wavelength of the incident light determines the primary charge separation pathway in Photosystem II.

Charge separation is a key component of the reactions cascade of photosynthesis, by which solar energy is converted to chemical energy. From this photochemical reaction, two radicals of opposite charge are formed, a highly reducing anion and a highly oxidising cation. We have previously proposed that the cation after far-red light excitation is located on a component different from PD1, which is the location of the primary electron hole after visible light excitation. Here, we attempt to provide further insight into the location of the primary charge separation upon far-red light excitation of PS II, using the EPR signal of the spin polarized 3P680 as a probe. We demonstrate that, under far-red light illumination, the spin polarized 3P680 is not formed, despite the primary charge separation still occurring at these conditions. We propose that this is because under far-red light excitation, the primary electron hole is localized on ChlD1, rather than on PD1. The fact that identical samples have demonstrated charge separation upon both far-red and visible light excitation supports our hypothesis that two pathways for primary charge separation exist in parallel in PS II reaction centres. These pathways are excited and activated dependent of the wavelength applied.

Acute social stress-induced immunomodulation in pigs high and low responders to ACTH.

Pig husbandry is known as an intensive breeding system, piglets being submitted to multiple stressful events such as early weaning, successive mixing, crowding and shipping. These stressors are thought to impair immune defences and might contribute, at least partly, to the prophylactic use of antibiotics. Robustness was recently defined as the ability of an individual to express a high-production potential in a wide variety of environmental conditions. Increasing robustness thus appears as a valuable option to improve resilience to stressors and could be obtained by selecting piglets upon their adrenocortical activity. In this study, we aimed at depicting the consequences of an acute social stress on the immune capacity of piglets genetically selected upon divergent hypothalamic-pituitary-adrenocortical (HPA) axis activity. For this purpose, we monitored neuroendocrine and immune parameters, in high- (HPAhi) and low- (HPAlo) responders to ACTH, just before and immediately after a one-hour mixing with unfamiliar conspecifics. As expected, stressed piglets displayed higher levels of circulating cortisol and norepinephrine. Blood cell count analysis combined to flow cytometry revealed a stress-induced leukocyte mobilization in the bloodstream with a specific recruitment of CD8α+ lymphocytes. Besides, one-hour mixing decreased LPS-induced IL-8 and TNFα secretions in whole-blood assays (WBA) and reduced mononuclear cell phagocytosis. Altogether, our data demonstrate that acute social stress alters immune competence of piglets from both groups, and bring new insights in favour of good farming practices. While for most parameters high- and low-responders to ACTH behaved similarly, HPAhi piglets displayed higher number of CD4+ CD8α- T cells, as well as increased cytokine production in WBA (LPS-induced TNFα and PIL-induced IL-8), which could confer them increased resistance to pathogens. Finally, a principal component analysis including all parameters highlighted that overall stress effects were less pronounced on piglets with a strong HPA axis. Thus, selection upon adrenocortical axis activity seems to reduce the magnitude of response to stress and appears as a good tool to increase piglet robustness.