Military load carriage: an innovative method of interface pressure measurement and evaluation of novel load carriage designs

This thesis is concerned with the measurement and effects of pressure on the body as a result of military load carriage. High skin pressures are associated with impaired blood flow, brachial plexus disorders and user pain and discomfort. Load carriage research has largely overlooked this issue, mainly due to the lack of an appropriate methodology. The thesis consists of two parts. The aim of part I was to develop and validate a novel method of measuring on-body interface pressures underneath military load carriage equipment. The Tekscan system was used, which provides 954 individual sensing elements over a total sensing area of 238.5cm2. A number of small experiments were undertaken to establish appropriate calibration and measurement error. A five-point rating scale was developed, and included within the experimental procedure; to measure user discomfort at the shoulder area where was 'no discomfort' and 5 was 'unbearably uncomfortable'. Following a pilot study the method was shown to produce reliable data that was sensitive to differences in design of load carriage systems within a comparative experimental design. [Continues.

<i>Chaetoceros</i> and <i>Thalassiosira</i> diversity and abundance as recorded during the morphology-based surveys in 2010 and 2011.

<p>PB = Passamaquoddy Bay; WV = The Wolves; J = January; F = February; M = March; A = April; My = May; Jun = June; Jul = July; Aug = August; S = September; O = October; N = November; and D = December.</p>a<p>n indicates the number of tow subsamples in which each taxon was present (n = 59 for 2010 and n = 46 for 2011).</p>b<p>Months are the months each taxon was present.</p>c<p>n>1 are the number of tow subsamples with a HELCOM rating>1.</p>d<p>Months n>1 are the months in which the higher abundance occurred.</p

A Comparison of Morphological and Molecular-Based Surveys to Estimate the Species Richness of <i>Chaetoceros</i> and <i>Thalassiosira</i> (Bacillariophyta), in the Bay of Fundy

<div><p>The goal of this study was to compare the ability of morphology and molecular-based surveys to estimate species richness for two species-rich diatom genera, <i>Chaetoceros</i> Ehrenb. and <i>Thalassiosira</i> Cleve, in the Bay of Fundy. Phytoplankton tows were collected from two sites at intervals over two years and subsampled for morphology-based surveys (2010, 2011), a culture-based DNA reference library (DRL; 2010), and a molecular-based survey (2011). The DRL and molecular-based survey utilized the 3′ end of the RUBISCO large subunit (<i>rbc</i>L-3P) to identify genetic species groups (based on 0.1% divergence in <i>rbc</i>L-3P), which were subsequently identified morphologically to allow comparisons to the morphology-based survey. Comparisons were compiled for the year (2011) by site (n = 2) and by season (n = 3). Of the 34 taxa included in the comparisons, 50% of taxa were common to both methods, 35% were unique to the molecular-based survey, and 12% were unique to the morphology-based survey, while the remaining 3% of taxa were unidentified genetic species groups. The morphology-based survey excelled at identifying rare taxa in individual tow subsamples, which were occasionally missed with the molecular approach used here, while the molecular methods (the DRL and molecular-based survey), uncovered nine cryptic species pairs and four previously overlooked species. The last mentioned were typically difficult to identify and were generically assigned to <i>Thalassiosira</i> spp. during the morphology-based survey. Therefore, for now we suggest a combined approach encompassing routine morphology-based surveys accompanied by periodic molecular-based surveys to monitor for cryptic and difficult to identify taxa. As sequencing technologies improve, molecular-based surveys should become routine, leading to a more accurate representation of species composition and richness in monitoring programs.</p></div

Comparisons between the number of species found during the morphology (morph) and molecular-based (mol) surveys.

<p>Data were summarized for the 2011-monitoring year (<b>A</b>), and then by site (<b>B</b>), and by season (<b>C</b>). In the year summary (<b>A</b>), taxa were placed into five main categories in bold font (two of these were divided further into three subcategories each) as indicated on the figure and described in the text. In the by site (<b>B</b>) and by season (<b>C</b>) summaries, the taxa are placed in only three categories including taxa that were identified: in common to the morphology (morph) and molecular (mol) -based surveys (black); or in the morphology-based survey only (white); in the molecular-based survey only as unique (gray) or cryptic (vertical lines) species. Sites were Passamaquoddy Bay (PB) and The Wolves (WV). Seasons were Jan, Apr, May (winter), June–Sept (summer), and Oct–Dec (fall).</p

Example of a morphological species-discovery curve used to determine when colony isolation should discontinue.

<p>This curve was generated for colonies isolated from the Passamaquoddy Bay plankton tow subsamples on June 1, 2010 for development of the culture-based DNA reference library (DRL). Isolation was terminated after 60 mins (n = 42 colonies of 26 morphological species isolated) because 30 mins had elapsed with no new morphological types found.</p

Table_1_A first look at childhood abuse in women with obstructive sleep apnea.XLSX

Study objectivesWomen who experienced childhood sexual abuse have higher rates of obesity, a risk factor for obstructive sleep apnea (OSA). We assessed if prior childhood sexual abuse was more common in women with OSA vs. those in the control group, with possible mediation by obesity.MethodsIn a secondary analysis of a larger project, we studied 21 women with OSA (age mean ± SD 59 ± 12 years, body mass index [BMI] 33 ± 8 kg/m2, respiratory event index [REI] 25 ± 16 events/hour, and Epworth Sleepiness Scale [ESS] score 8 ± 5) and 21 women without OSA (age 53 ± 9 years, BMI 25 ± 5 kg/m2, REI [in 7/21 women] 1 ± 1 events/hour, and ESS score, 5 ± 3). We evaluated four categories of trauma (general, physical, emotional, and sexual abuse) with the Early Trauma Inventory Self-Report–Short Form (ETISR-SF). We assessed group differences in trauma scores with independent samples t-tests and multiple regressions. Parametric Sobel tests were used to model BMI as a mediator for individual trauma scores predicting OSA in women.ResultsEarly childhood sexual abuse reported on the ETISR-SF was 2.4 times more common in women with vs. without OSA (p = 0.02 for group difference). Other trauma scores were not significantly different between women with and without OSA. However, BMI was a significant mediator (p = 0.02) in predicting OSA in women who experienced childhood physical abuse.ConclusionChildhood sexual abuse was more common in women with vs. without OSA. BMI was a mediator for OSA of childhood physical but not sexual abuse. This preliminary hypothesis-generating study suggests that there may be physiological impacts of childhood trauma in women that predispose them to OSA.</p

Compound 10 demonstrated weak inhibitory activity.

<p><b>A.</b> Differential scanning fluorimetry profile with increasing concentrations of compound <b>10</b>. Similar to all other compounds tested, there was no significant shift in the unfolding temperature of EcDsbA up to 2 mM of compound <b>10</b>. <b>B.</b> ITC profile of EcDsbA titration by compound <b>10</b>, which shows no detectable binding under the conditions used (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133805#sec002" target="_blank">methods</a> for details). A similar outcome was found for the other 9 compounds. <b>C.</b> Compound <b>10</b> was the only one of the ten tested peptidomimetics that exhibited detectable activity in the DsbA assay, inducing a reduction in DsbA folding activity. <b>D.</b> Plotting the log of the peptidomimetic concentration against the rate of fluorescence increase measured in the enzyme assay allowed fitting of a sigmoidal curve and an estimated IC₅₀ value of ~1 mM for compound <b>10</b>. The positive control with no compound is shown as a white circle.</p

The DsbA-DsbB interaction.

<p><b>A.</b> Schematic showing the proposed mechanism of oxidative folding in the periplasm of Gram-negative bacteria. DsbA catalyses the formation of a disulfide bond in a protein substrate, then interacts with DsbB to which it transfers electrons so that DsbA is regenerated into its active oxidized state. The electrons are subsequently transferred from DsbB to ubiquinone (UQ) and ultimately to the respiratory complex. <b>B.</b> The binding interface between EcDsbA (black and red) and EcDsbB loop P2 (blue) derived from the crystal structure of the EcDsbAC33A:EcDsbBC130S complex [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133805#pone.0133805.ref037" target="_blank">37</a>]. The EcDsbA hydrophobic groove residues are highlighted in orange shading, the intermolecular disulfide bond is shown as a solid red line and the hydrogen bond with the <i>cis</i>Pro loop is shown as a dashed red line. <b>C.</b> The binding interface between PmDsbA (black and red) and the peptide PWATCDS (blue) from the crystal structure of the complex [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133805#pone.0133805.ref038" target="_blank">38</a>]. In this complex there is no disulfide bond as the active site cysteine of PmDsbA was mutated to Ser (S30). The peptide Cys5 residue points away from the binding interface. Residues W2 and P1 of the peptide both interact with the hydrophobic groove (in orange) and these interactions were used as the target for this peptidomimetic design.</p

Chemical structures of the 10 peptidomimetic compounds synthesized and tested in this work.

<p>Compound <b>1</b> is the hit from the virtual screening from which derivatives <b>2</b>–<b>10</b> were designed.</p

Synthetic route for the tripeptide peptidomimetics.

<p>Synthetic route for the tripeptide peptidomimetics.</p