Optimal Sampling of a Chemical Hazard Area

This thesis proposes a methodology for optimally sampling a chemical hazard area subsequent to a chemical weapons attack. The objective is to identify the maximum number of areas that no longer require protective gear for safe operations. We model the area as an undirected graph and employ network analysis techniques to provide a methodological framework for identifying an optimal sampling sequence within a fixed time limit. We propose four models that characterize the secondary vapor concentrations: i) static and deterministic, ii) static and stochastic, iii) dynamic and deterministic, and iv) dynamic and stochastic. Comparisons of the static cases and their dynamic counterparts demonstrate the impact of temporal evolution of vapor concentrations on the optimal sampling path. We conclude that the number of safe areas may be either under- or over-estimated depending on the assumed nature of the secondary vapors

Differences in physical activity domains, guideline adherence, and weight history between metabolically healthy and metabolically abnormal obese adults: a cross-sectional study

BACKGROUND: Despite the accepted health consequences of obesity, emerging research suggests that a significant segment of adults with obesity are metabolically healthy (MHO). To date, MHO individuals have been shown to have higher levels of physical activity (PA), but little is known about the importance of PA domains or the influence of weight history compared to their metabolically abnormal (MAO) counterpart. OBJECTIVE: To evaluate the relationship between PA domains, PA guideline adherence, and weight history on MHO. METHODS: Pooled cycles of the National Health and Nutritional Examination Survey (NHANES) 1999–2006 (≥20 y; BMI ≥ 30 kg/m(2); N = 2,753) and harmonized criteria for metabolic syndrome (MetS) were used. Participants were categorized as “inactive” (no reported PA), “somewhat active” (>0 to < 500 metabolic equivalent (MET) min/week), and “active” (PA guideline adherence, ≥ 500 MET min/week) according to each domain of PA (total, recreational, transportation and household). Logistic and multinomial regressions were modelled for MHO and analyses were adjusted for age, sex, education, ethnicity, income, smoking and alcohol intake. RESULTS: Compared to MAO, MHO participants were younger, had lower BMI, and were more likely to be classified as active according to their total and recreational PA level. Based on total PA levels, individuals who were active had a 70 % greater likelihood of having the MHO phenotype (OR = 1.70, 95 % CI: 1.19–2.43); however, once stratified by age (20–44 y; 45–59 y; and; ≥60 y), the association remained significant only amongst those aged 45–59 y. Although moderate and vigorous PA were inconsistently related to MHO following adjustment for covariates, losing ≥30 kg in the last 10 y and not gaining ≥10 kg since age 25 y were significant predictors of MHO phenotype for all PA domains, even if adherence to the PA guidelines were not met. CONCLUSION: Although PA is associated with MHO, the beneficial effects of PA may be moderated by longer-term changes in weight. Longitudinal analysis of physical activity and weight change trajectories are necessary to isolate the contribution of duration of obesity, PA behaviours, and longer-term outcomes amongst MHO individuals

Enhanced Immunogenicity, Mortality Protection, and Reduced Viral Brain Invasion by Alum Adjuvant with an H5N1 Split-Virion Vaccine in the Ferret

Pre-pandemic development of an inactivated, split-virion avian influenza vaccine is challenged by the lack of pre-existing immunity and the reduced immunogenicity of some H5 hemagglutinins compared to that of seasonal influenza vaccines. Identification of an acceptable effective adjuvant is needed to improve immunogenicity of a split-virion avian influenza vaccine.No serum antibodies were detected after vaccination with unadjuvanted vaccine, whereas alum-adjuvanted vaccination induced a robust antibody response. Survival after unadjuvanted dose regimens of 30 µg, 7.5 µg and 1.9 µg (21-day intervals) was 64%, 43%, and 43%, respectively, yet survivors experienced weight loss, fever and thrombocytopenia. Survival after unadjuvanted dose regimen of 22.5 µg (28-day intervals) was 0%, suggesting important differences in intervals in this model. In contrast to unadjuvanted survivors, either dose of alum-adjuvanted vaccine resulted in 93% survival with minimal morbidity and without fever or weight loss. The rarity of brain inflammation in alum-adjuvanted survivors, compared to high levels in unadjuvanted vaccine survivors, suggested that improved protection associated with the alum adjuvant was due to markedly reduced early viral invasion of the ferret brain.Alum adjuvant significantly improves efficacy of an H5N1 split-virion vaccine in the ferret model as measured by immunogenicity, mortality, morbidity, and brain invasion

Neurovirulence of H5N1 infection in ferrets is mediated by multifocal replication in distinct permissive neuronal cell regions.

Highly pathogenic avian influenza A (HPAI), subtype H5N1, remains an emergent threat to the human population. While respiratory disease is a hallmark of influenza infection, H5N1 has a high incidence of neurological sequelae in many animal species and sporadically in humans. We elucidate the temporal/spatial infection of H5N1 in the brain of ferrets following a low dose, intranasal infection of two HPAI strains of varying neurovirulence and lethality. A/Vietnam/1203/2004 (VN1203) induced mortality in 100% of infected ferrets while A/Hong Kong/483/1997 (HK483) induced lethality in only 20% of ferrets, with death occurring significantly later following infection. Neurological signs were prominent in VN1203 infection, but not HK483, with seizures observed three days post challenge and torticollis or paresis at later time points. VN1203 and HK483 replication kinetics were similar in primary differentiated ferret nasal turbinate cells, and similar viral titers were measured in the nasal turbinates of infected ferrets. Pulmonary viral titers were not different between strains and pathological findings in the lungs were similar in severity. VN1203 replicated to high titers in the olfactory bulb, cerebral cortex, and brain stem; whereas HK483 was not recovered in these tissues. VN1203 was identified adjacent to and within the olfactory nerve tract, and multifocal infection was observed throughout the frontal cortex and cerebrum. VN1203 was also detected throughout the cerebellum, specifically in Purkinje cells and regions that coordinate voluntary movements. These findings suggest the increased lethality of VN1203 in ferrets is due to increased replication in brain regions important in higher order function and explains the neurological signs observed during H5N1 neurovirulence

VN1203 infected and replicated in Purkinje cells and deep cerebellar nuclei of the cerebellum.

<p>Representative sections of the cerebellum of ferrets instilled with allantoic fluid (<b>A,B,G,H</b>), HK483 (<b>C,D,I,J</b>), VN1203 (<b>E,F,K,L</b>). Viral antigen was detected with IMGENEX 5187-A for avian influenza A NP and visualized with DAB. Brown stain indicates the presence of virus. Counterstained with Luxol fast blue. (<b>B–F</b>) higher magnification of boxes in A–E respectively. H) White arrow indicates molecular layer, black arrow indicates granule layer, black arrowhead indicates a Purkinje cell, white arrowhead indicates Purkinje cell axons. <b>L</b>) Arrow indicates infected granule cell and arrowhead indicates infected Purkinje cell. Scale bars represent: <b>A,C,E,G,I,K</b>) 2 mm; <b>B,D,F,H,J,L</b>) 300 µm.</p

VN1203 was more lethal than HK483 in ferrets despite similar weight loss in non-survivors.

<p><b>A.</b> Survival of ferrets intranasally challenged with allantoic fluid (N = 2), A/Vietnam/1203/2004 (VN1203) (N = 10) or A/Hong Kong/483/1997 (HK483) N = 10, ***, p<.0001. <b>B.</b> Mean ± SEM of bodyweight of ferrets instilled with VN1203 or HK483. N = 8 HK483 survivors, N = 2 HK483 non-survivors, N = 10 VN1203 non-survivors, N = 2 control.</p

VN1203 induced significant pathology despite similar nasal turbinate titers in ferrets infected with either virus.

<p><b>A.</b> H&E stained section a primary differentiated ferret nasal turbinate cell monolayer. <b>B.</b> Primary differentiated ferret nasal turbinate cells were infected with VN1203 or HK483 at an MOI of 0.001. Mean ± SEM of N = 4 samples per virus at each time point. <b>C.</b> Viral titers of homogenized nasal turbinates were graphed as mean ± SEM for VN1203 or HK483 infected ferrets. <b>D–I</b>. Representative samples of nasal turbinate tissue of ferrets instilled with allantoic fluid (<b>D,G</b>), HK483 (<b>E,H</b>), or VN1203 (<b>F,I</b>). <b>D–F</b> were stained with H&E, <b>G–I</b> were stained with anti-avian influenza NP and counterstained with Luxol fast blue. <b>F.</b> # indicates inflammatory cells infiltrating the underlying stroma. <b>H,I.</b> Arrows point to H5N1 infected cells. Scale bars: <b>A.</b> 50 µm; <b>D–F</b>, 300 µm; <b>G–I</b>, 100 µm.</p

Viral titers and histopathology were similar in the lung of H5N1 infected ferrets.

<p><b>A.</b> Viral titers and <b>B.</b> viral RNA was measured from four sections of the lung per ferret. <b>A,B</b>) Data represents the mean ± SEM from four lung regions of N = 1, VN1203 4 dpi, N = 3, VN1203 6 dpi, N = 6, HK483 4, 6, and 8 dpi. Dorsal view of ferret lung following intranasal instillation with allantoic fluid (<b>C</b>), HK483 (<b>D</b>), VN1203 (<b>E</b>). Lung sections stained with H&E of ferrets instilled with allantoic fluid (<b>F</b>), HK483 (<b>G</b>), VN1203 (<b>H</b>). <b>F–H</b>) scale bars = 600 µm.</p

VN1203 infection resulted in multifocal infection in the cerebral cortex of ferrets.

<p>Representative sections of the cerebrum of ferrets intranasally instilled with VN1203 (<b>A, C–E</b>) and HK483 (<b>B</b>). Viral antigen was detected with IMGENEX-5187A for avian influenza A NP and visualized with DAB. Brown stain indicates the presence of virus. Counterstained with Luxol fast blue. Scale bars represent 10 mm. cc: corpus collosum, ic: internal capsule, ot: optical tract, h: hippocampus, lv: lateral ventricle, oc: olfactory cortex, cp: cerebral peduncle.</p