Gyroscopic corrections improve wearable sensor data prior to measuring dynamic sway in the gait of people with Multiple Sclerosis

Accelerometers are incorporated into many consumer devices providing new ways to monitor gait, mobility, and fall risk. However, many health benefits have not been realised because of issues with data quality that results from gravitational ‘cross-talk’ when the wearable device is tilted. Here we present an adaptive filter designed to improve the quality of accelerometer data prior to measuring dynamic pelvic sway patterns during a six minute walk test in people with and without Multiple Sclerosis (MS). Optical motion capture was used as the gold standard. Improved wearable device accuracy (≤4.4% NRMSE) was achieved using gyroscopic corrections and scaling filter thresholds by step frequency. The people with MS presented significantly greater pelvis sway range to compensate for their lower limb weaknesses and joint contractures. The visualisation of asymmetric pelvic sway in people with MS illustrates the potential to better understand their mobility impairments for reducing fall risk.     

Development of nested multiplex polymerase chain reaction (PCR) assay for the detection of Toxocara canis, Toxocara cati and Ascaris suum contamination in meat and organ meats

Ascarid Larva Migrans Syndrome (ascarid LMS) is a clinical syndrome in humans, caused by the migration of animal roundworm larvae such as Toxocara canis, Toxocara cati and Ascaris suum. Humans may acquire infection by ingesting embryonated eggs, or infective larvae of these parasites in contaminated meat and organ meats. To detect these pathogenic contaminations, a novel nested multiplex PCR system was developed. Our novel nested multiplex PCR assay showed specific amplification of T. canis, T. cati and Ascaris spp. Detection limit of the nested multiplex PCR was tested with serial dilution of T. canis, T. cati or A. suum genomic DNA (gDNA) from 100?pg to 100 ag and found to be 10?fg, 1?fg and 100?fg, respectively. When larvae were spiked into chicken liver tissue, DNA of T. canis and A. suum was detected from the liver spiked with a single larva, while the assay required at least 2 larvae of T. cati. Moreover, the ascarid DNA was detected from the liver of mice infected with 100 and 300 eggs of T. canis, T. cati or A. suum. This nested multiplex PCR assay could be useful for the detection of contamination with ascarid larvae in meat and organ meats.     

Kinetic nonoptimality and vibrational stability of proteins

Scaling of folding times in Go models of proteins and of decoy structures with the Lennard-Jones potentials in the native contacts reveal power law trends when studied under optimal folding conditions. The power law exponent depends on the type of native geometry. Its value indicates lack of kinetic optimality in the model proteins. In proteins, mechanical and thermodynamic stabilities are correlated.     

Morphological,molecular and MALDI-TOF MS identification of ticks and tick-associated pathogens in Vietnam

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising and reliable tool for arthropod identification, including the identification of alcohol-preserved ticks based on extracted leg protein spectra. In this study, the legs of 361 ticks collected in Vietnam, including 251 Rhiphicephalus sanguineus s.l, 99 Rhipicephalus (Boophilus) microplus, two Amblyomma varanensis, seven Dermacentor auratus, one Dermacentor compactus and one Amblyomma sp. were submitted for MALDI-TOF MS analyses. Spectral analysis showed intra-species reproducibility and inter-species specificity and the spectra of 329 (91%) specimens were of excellent quality. The blind test of 310 spectra remaining after updating the database with 19 spectra revealed that all were correctly identified with log score values (LSV) ranging from 1.7 to 2.396 with a mean of 1.982 ± 0.142 and a median of 1.971. The DNA of several microorganisms including Anaplasma platys, Anaplasma phagocytophilum, Anaplasma marginale, Ehrlichia rustica, Babesia vogeli, Theileria sinensis, and Theileria orientalis were detected in 25 ticks. Co-infection by A. phagocytophilum and T. sinensis was found in one Rh. (B) microplus.     

Universality classes in folding times of proteins

Molecular dynamics simulations in simplified models allow one to study the scaling properties of folding times for many proteins together under a controlled setting. We consider three variants of the Go models with different contact potentials and demonstrate scaling described by power laws and no correlation with the relative contact order parameter. We demonstrate existence of at least three kinetic universality classes that are correlated with the types of structure: the alpha-, alpha-beta-, and beta- proteins have the scaling exponents of approximately 1.7, 2.5, and 3.2, respectively. The three classes merge into one when the contact range is truncated at a reasonable value. We elucidate the role of the potential associated with the chirality of a protein.     

Stress relaxation of human ankles is only minimally affected by knee and ankle angle

Comprehensive characterization of stress relaxation in musculotendinous structures is needed to create robust models of viscoelastic behavior. The commonly used quasi-linear viscoelastic (QLV) theory requires that the relaxation response be independent of tissue strain (length). This study aims to characterize stress relaxation in the musculotendinous and ligamentous structures crossing the human ankle (ankle-only structures and the gastrocnemius muscle–tendon unit, which crosses the ankle and knee), and to determine whether stress relaxation is independent of the length of these structures. Two experiments were conducted on 8 healthy subjects. The first experiment compared stress relaxation over 10 min at different gastrocnemius muscle–tendon unit lengths keeping the length of ankle-joint only structures fixed. The second experiment compared stress relaxation at different lengths of ankle-joint only structures keeping gastrocnemius muscle–tendon unit length fixed. Stress relaxation data were fitted with a two-term exponential function (T=G₀+G₁e^?λ₁t+G₂e^?λ₂t). The first experiment demonstrated a significant effect of gastrocnemius muscle–tendon unit length on G₁, and the second experiment demonstrated an effect of the length of ankle-joint only structures on G₂, λ₁ and λ₂ (p<0.05). Nonetheless, the size of effects on stress relaxation was small (ΔG/G<10%), similar to experimental variability. We conclude that stress relaxation in the relaxed human ankle is minimally affected by changing gastrocnemius muscle–tendon unit length or by changing the lengths of ankle-joint only structures. Consequently quasi-linear viscoelastic models of the relaxed human ankle can use a common stress relaxation modulus at different knee and ankle angles with minimal error.     

Efficient surface patterning of oligonucleotides inside a glass capillary through oxime bond formation

The efficient surface patterning of oligonucleotides was accomplished onto the inner wall of fused-silica capillary tubes as well as on the surface of glass slides through oxime bond formation. The robustness of the method was demonstrated by achieving the surface immobilization of up to three different oligonucleotide sequences inside the same capillary tube. The method involves the preparation of surfaces grafted with reactive aminooxy functionalities masked with the photocleavable protecting group, 2-(2-nitrophenyl) propyloxycarbonyl group (NPPOC). Briefly, NPPOC-aminooxy silane 1 was prepared and used to silanize the glass surfaces. The NPPOC group was cleaved under brief irradiation to unmask the reactive aminooxy group on surfaces. These reactive aminooxy groups were allowed to react with aldehyde-containing oligonucleotides to achieve an efficient surface immobilization. The advantage associated with the present approach is that it combines the high-coupling efficiency of oxime bond formation with the convenience associated with the use of photolabile groups. The present strategy thus offers an alternative approach for the immobilization of biomolecules in the microchannels of "labs on a chip" devices.     

Plant defense in response to chewing insects: proteome analysis of Arabidopsis thaliana damaged by Plutella xylostella

The interactions between Arabidopsis thaliana and Plutella xylostella have been considered as a model system to unravel the responses of plants to herbivorous insects. Here, we use a 2-DE proteome approach to detect protein expression changes in the leaves of Arabidopsis plants exposed to P. xylostella larval infestation at 27°C within 8?h. Approximately 450 protein spots were reproducibly detected on gels. Of these, comparing healthy and infested leaves, we identified 18 differentially expressed protein spots. Thirteen proteins were successfully identified by MALDI-TOF/MS and LC-ESI-MS/MS. Functional classification analysis indicated that the differentially identified proteins were associated with amino acid, carbohydrate, energy, lipid metabolism, and photosynthesis. In addition, their relative abundances were assessed according to larval pest feeding on Arabidopsis leaves. These data provide valuable new insights for further works in plant-biotic and environmental stress interaction.     

Activation of Metabotropic Glutamate Receptors Inhibits Synapsin I Phosphorylation in Visceral Sensory Neurons

Activation of glutamate metabotropic receptors (mGluRs) in nodose ganglia neurons has previously been shown to inhibit voltage-gated Ca⁺⁺ currents and synaptic vesicle exocytosis. The present study describes the effects of mGluRs on depolarization-induced phosphorylation of the synaptic-vesicle-associated protein synapsin I. Depolarization of cultured nodose ganglia neurons with 60 mm KCl resulted in an increase in synapsin I phosphorylation. Application of mGluR agonists 1-aminocyclopentane-1s-3r-dicarboxylic acid (t-ACPD) and L(+)-2-Amino-4-phosphonobutyric acid (L-AP4) either in combination or independently inhibited the depolarization induced phosphorylation of synapsin I. Application of the mGluR antagonist (RS)-α-Methyl-4-carboxyphenylglycine (MCPG) blocked t-ACPD-induced inhibition of synapsin phosphorylation but not the effects of L-AP4. In addition, application of either t-ACPD or L-AP4 in the absence of KCl induced depolarization had no effect on resting synapsin I phosphorylation. RT-PCR analysis of mGluR subtypes in these nodose ganglia neurons revealed that these cells only express group III mGluR subtypes 7 and 8. These results suggest that activation of mGluRs modulates depolarization-induced synapsin I phosphorylation via activation of mGluR7 and/or mGluR8 and that this process may be involved in mGluR inhibition of synaptic vesicle exocytosis in visceral sensory neurons of the nodose ganglia. Received 28 June 2000/Revised: 11 September 2000     

Malate metabolism in Hoya carnosa mitochondria and its role in photosynthesis during CAM phase III

This study investigated the respiratory properties and the role of the mitochondria isolated from one phosphoenolpyruvate carboxykinase (PCK)-CAM plant, Hoya carnosa, in malate metabolism during CAM phase III. The mitochondria showed high malate dehydrogenase (mMDH) and aspartate amino transferase (mAST), and a significant amount of malic enzyme (mME) activities. H. carnosa readily oxidized malate via mME and mMDH in the presence of some cofactors such as thiamine pyrophosphate (TPP), coenzyme A (CoA) or NAD(+). A high respiration rate of malate oxidation was observed at pH 7.2 with NAD(+) and glutamate (Glu). Providing AST and Glu simultaneously into the respiratory medium strongly increased the rates of malate oxidation, and this oxidation was gradually inhibited by an inhibitor of alpha-ketoglutarate (alpha-KG) carrier, pyridoxal-5'-phosphate (PLP). The mitochondria readily oxidized aspartate (Asp) or alpha-KG individually with low rates, while they oxidized Asp and alpha-KG simultaneously with high rates, and this simultaneous oxidation was also inhibited by PLP. By measuring the capacity of the mitochondrial shuttle, it was found that the OAA produced via mMDH seemed not to be transported outside the mitochondria, but mAST interconverted OAA and Glu to Asp and alpha-KG, respectively, and exported them out via a malate-aspartate (malate-Asp) shuttle. The data in this research suggest that during phase III of PCK-CAM, H. carnosa mitochondria oxidized malate via both mME and the mMDH systems depending on metabolic requirements. However, malate metabolism by the mMDH system did not operate via a malate-OAA shuttle similarly to Ananas comosus mitochondria, but it operated via a malate-Asp shuttle similarly to Kalancho? daigremontiana mitochondria.