Modeling the Metabolic Reductions of a Passive Back-Support Exoskeleton

Despite several attempts to quantify the metabolic savings resulting from the use of passive back-support exoskeletons (BSEs), no study has modeled the metabolic change while wearing an exoskeleton during lifting. The objectives of this study were to: 1) quantify the metabolic reductions due to the VT-Lowe's exoskeleton during lifting; and 2) provide a comprehensive model to estimate the metabolic reductions from using a passive BSE. In this study, 15 healthy adults (13M, 2F) of ages 20 to 34 years (mean=25.33, SD=4.43) performed repeated freestyle lifting and lowering of an empty box and a box with 20% of their bodyweight. Oxygen consumption and metabolic expenditure data were collected. A model for metabolic expenditure was developed and fitted with the experimental data of two prior studies and the without-exoskeleton experimental results. The metabolic cost model was then modified to reflect the effect of the exoskeleton. The experimental results revealed that VT-Lowe's exoskeleton significantly lowered the oxygen consumption by ~9% for an empty box and 8% for a 20% bodyweight box, which corresponds to a net metabolic cost reduction of ~12% and ~9%, respectively. The mean metabolic difference (i.e., without-exo minus with-exo) and the 95% confidence interval were 0.36 and (0.2-0.52) [Watts/kg] for 0% bodyweight, and 0.43 and (0.18-0.69) [Watts/kg] for 20% bodyweight. Our modeling predictions for with-exoskeleton conditions were precise, with absolute freestyle prediction errors of <2.1%. The model developed in this study can be modified based on different study designs, and can assist researchers in enhancing designs of future lifting exoskeletons.

Assessing Calcium and Magnesium Nutritional Status With the Hair Median Derivatives Bioassay

Objectives Short-term biological indicator of urinary Mg and Ca excretion helps us to assess human body Mg and Ca nutritional status. In this study, we used the long-term biological indicator tissue of hair to assess Mg and Ca human body nutritional status. Methods Hair Mg and Ca were analyzed in 1073 healthy white adult Caucasians [734 women (♀) and 339 men (♂)] consuming common mid-European diet, with the ICP MS. The log transformed data on hair magnesium and calcium were analyzed with median derivatives bioassay. Results The median values (μg·g−1) were ♀Mg 137.2 and ♂Mg 47.1, and ♀Ca 1721.4 and ♂Ca 492.0, respectively. The linear (adequate) reference ranges of the sigmoid saturation curve for magnesium were ♀Mg 29.7–270.6 and ♂Mg 20.5–90.2, whereas these ranges for calcium were ♀Ca 487.7–4426.8 and ♂Ca 261.1–816.4. The magnesium to calcium (Mg/Ca) ratio in women appears fairly constant along the sigmoid linear segment range (about 0.067), and in difference to the constantly increasing Mg/Ca ratio in men - from 0.078 at the start of the linear segment to 0.096 at the median and 0.1105 before leveling at the top of the curve. Conclusions Women tend to accumulate much more Ca in their hair than men. The results suggest how hair Mg concentration should not be below 29.7 and 20.5 or above 270.6 and 90.2 μg·g−1 in women and men, respectively. Similarly, Ca hair concentrations should be not below 487.7 and 261.1 and higher than 4456.8 and 816.4 in women and men, respectively. The possible health effects of the observed sex related metabolic difference between men and women remains to be elucidated. Funding Sources The authors received no specific funding for this work.

Folic Acid Antagonists: Antimicrobial and Immunomodulating Mechanisms and Applications

: Bacterial, protozoan and other microbial infections share an accelerated metabolic rate. In order to ensure a proper functioning of cell replication and proteins and nucleic acids synthesis processes, folate metabolism rate is also increased in these cases. For this reason, folic acid antagonists have been used since their discovery to treat different kinds of microbial infections, taking advantage of this metabolic difference when compared with human cells. However, resistances to these compounds have emerged since then and only combined therapies are currently used in clinic. In addition, some of these compounds have been found to have an immunomodulatory behavior that allows clinicians using them as anti-inflammatory or immunosuppressive drugs. Therefore, the aim of this review is to provide an updated state-of-the-art on the use of antifolates as antibacterial and immunomodulating agents in the clinical setting, as well as to present their action mechanisms and currently investigated biomedical applications.

Comparative metabolomic analysis of caecal digesta between Jinhua pig and Landrace pig

The metabolic difference in caecal digesta between Jinhua pig and Landrace pig was compared. Twenty weaned piglets at 28 days of age, including ten Landrace pigs (a Western pig breed) and ten Jinhua pigs (a Chinese native pig breed), were randomly selected and allocated into two groups. The pigs were fed the same corn-soybean diet on the same pig farm. At the age of 240 days, all pigs of each group were slaughtered, the digesta in the caecum of the twenty pigs were collected for metabolomic analysis and determination of short-chain fatty acids (SCFAs). The results showed that a total of 56 different metabolites (22 metabolites named and 34 metabolites without identification) were detected in caecal digesta using a gas chromatography time-of-flight/mass spectrometry (GC-TOF-MS)-based metabolomic approach. Forty-six of the 56 metabolites were upregulated significantly (P &lt; 0.05) in Landrace group compared with Jinhua group. The metabolic pathways with different impact value in which different metabolites were mainly involved were tyrosine metabolism, citrate cycle and steroid biosynthesis. In addition, we found that Landrace accumulated more SCFAs in caecal digesta, while the concentrations of acetic acid (P &lt; 0.01) and butyric acid (P &lt; 0.05) in caecal digesta of Jinhua pig were markedly lower than those of Landrace pig. Collectively, our study was the first to compare the metabolic difference in caecal digesta between Jinhua pig and Landrace pig using a metabolomics approach, which might be used as a potential metabolomics mechanism to research different breeds of pigs.

Transcriptomic analysis of Bama pig's liver in various nutritional states reveals a metabolic difference of fatty acids

Both fasting and treatment with a high-fat diet (HFD) can dramatically change fat metabolism in the liver.