Master of Science

thesisMine fires and explosions associated with spontaneous combustion (sponcom) can be the cause of mines closings temporarily or permanently. The risk of fatalities and production losses are also associated with the hazards of sponcom. Over the last 175 years, nearly 13,000 deaths have been recorded and are attributed to mine fires or explosions in the United States coal mines. Some of these fires could have been prevented with proper ventilation precautions. Ventilation is a primary tool used to prevent fires and explosions in an underground mining environment. Removing contaminants with proper air flow rate is the general method for preventing fires and explosions. Another method for fire prevention is pressure balancing. Pressure balancing is a technique of redistribution of the air pressure in areas where there is potential for sponcom. The implementation of passive and dynamic pressure balancing methods can be used to reduce the risk of spontaneous combustions and accumulation of explosive gas mixtures in confined areas. These methods have been applied in mines outside of the United States, mostly practiced in Australia, India, and some European countries. Pressure balancing, when applied correctly, may reduce or eliminate the flow of air through caved areas, thus reducing the possibility of self-heating of coal in critical areas where sponcom is more prevalent. Each mine in the United States will have different ventilation designs that are either classified as Bleeder or Bleederless with multiple variations in design. Passive and active pressure balancing designs were engineered for two underground longwall mines, one ventilated by a bleeder system and the other by a bleederless system. The study includes pressure quantity surveys in these coal mines, computer simulation exercises, and laboratory tests performed at the University of Utah. The simulations of surveyed coal mine models have been compared with field data and model data to produce results of potential pressure balancing implementations. The results have been analyzed and compared to each other, and used to develop strategies to prevent spontaneous combustion, create safe working conditions, and minimize ventilation requirement

Regular treatment with salmeterol and inhaled steroids for chronic asthma: serious adverse events

Epidemiological evidence has suggested a link between beta(2)-agonists and increased asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe.ObjectivesThe aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular salmeterol with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.Search strategyTrials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to salmeterol were also checked. The date of the most recent search was October 2008.Selection criteriaControlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular salmeterol and inhaled corticosteroids (in separate or combined inhalers), and were of at least 12 weeks duration.Data collection and analysisTwo authors independently selected trials for inclusion in the review. Outcome data were independently extracted by two authors. Unpublished data on mortality and serious adverse events were obtained from the sponsors, and from FDA submissions.Main resultsThe review included 30 studies (10,873 participants) in adults and adolescents, and three studies (1,173 participants) in children. The overall risk of bias was low and data on serious adverse events were obtained from all studies.Six deaths occurred in 5,710 adults on regular salmeterol with inhaled corticosteroids, and five deaths in 5,163 adults on regular inhaled corticosteroids at the same dose. The difference was not statistically significant (Peto OR 1.05; 95% CI 0.32 to 3.47) and the absolute difference between groups in risk of death of any cause was 0.00005 (95% CI -0.002 to 0.002). No deaths were reported in 1,173 children, and no deaths were reported to be asthma-related.Non-fatal serious adverse events of any cause were reported in 134 adults on regular salmeterol with inhaled corticosteroids, compared to 103 adults on regular inhaled corticosteroids; again this was not a significant increase (Peto OR 1.17; 95% CI 0.90 to 1.52). The absolute difference in the risk of non-fatal serious adverse events was 0.003 (95% CI -0.002 to 0.009).There were three of 586 children with serious adverse events on regular salmeterol with inhaled corticosteroids, compared to four out of 587 on regular inhaled corticosteroids: there was no significant difference between treatments (Peto OR 0.75; 95% CI 0.17 to 3.31).Asthma-related serious adverse events were reported in 23 and 21 adults in each group respectively, a non-significant difference (Peto OR 0.95; 95% CI 0.52 to 1.73), and only one event was reported in children.Authors' conclusionsNo significant differences have been found in fatal or non-fatal serious adverse events in trials in which regular salmeterol has been randomly allocated with inhaled corticosteroids, in comparison to inhaled corticosteroids at the same dose. Although 10,873 adults and 1,173 children have been included in trials, the number of patients suffering adverse events is too small, and the results are too imprecise to confidently rule out a relative increase in all-cause mortality or non-fatal adverse events. It is therefore not possible to determine whether the increase in all-cause non-fatal serious adverse events reported in the previous meta-analysis on regular salmeterol alone is abolished by the additional use of regular inhaled corticosteroids. The absolute difference between groups in the risk of serious adverse events was small. There were no asthma-related deaths and few asthma-related serious adverse events. Clinical decisions and information for patients regarding regular use of salmeterol have to take into account the balance between known symptomatic benefits of salmeterol and the degree of uncertainty and concern associated with its potential harmful effects

Lecanemab in early Alzheimer\u27s disease

BACKGROUND: The accumulation of soluble and insoluble aggregated amyloid-beta (Aβ) may initiate or potentiate pathologic processes in Alzheimer\u27s disease. Lecanemab, a humanized IgG1 monoclonal antibody that binds with high affinity to Aβ soluble protofibrils, is being tested in persons with early Alzheimer\u27s disease. METHODS: We conducted an 18-month, multicenter, double-blind, phase 3 trial involving persons 50 to 90 years of age with early Alzheimer\u27s disease (mild cognitive impairment or mild dementia due to Alzheimer\u27s disease) with evidence of amyloid on positron-emission tomography (PET) or by cerebrospinal fluid testing. Participants were randomly assigned in a 1:1 ratio to receive intravenous lecanemab (10 mg per kilogram of body weight every 2 weeks) or placebo. The primary end point was the change from baseline at 18 months in the score on the Clinical Dementia Rating-Sum of Boxes (CDR-SB; range, 0 to 18, with higher scores indicating greater impairment). Key secondary end points were the change in amyloid burden on PET, the score on the 14-item cognitive subscale of the Alzheimer\u27s Disease Assessment Scale (ADAS-cog14; range, 0 to 90; higher scores indicate greater impairment), the Alzheimer\u27s Disease Composite Score (ADCOMS; range, 0 to 1.97; higher scores indicate greater impairment), and the score on the Alzheimer\u27s Disease Cooperative Study-Activities of Daily Living Scale for Mild Cognitive Impairment (ADCS-MCI-ADL; range, 0 to 53; lower scores indicate greater impairment). RESULTS: A total of 1795 participants were enrolled, with 898 assigned to receive lecanemab and 897 to receive placebo. The mean CDR-SB score at baseline was approximately 3.2 in both groups. The adjusted least-squares mean change from baseline at 18 months was 1.21 with lecanemab and 1.66 with placebo (difference, -0.45; 95% confidence interval [CI], -0.67 to -0.23; P\u3c0.001). In a substudy involving 698 participants, there were greater reductions in brain amyloid burden with lecanemab than with placebo (difference, -59.1 centiloids; 95% CI, -62.6 to -55.6). Other mean differences between the two groups in the change from baseline favoring lecanemab were as follows: for the ADAS-cog14 score, -1.44 (95% CI, -2.27 to -0.61; P\u3c0.001); for the ADCOMS, -0.050 (95% CI, -0.074 to -0.027; P\u3c0.001); and for the ADCS-MCI-ADL score, 2.0 (95% CI, 1.2 to 2.8; P\u3c0.001). Lecanemab resulted in infusion-related reactions in 26.4% of the participants and amyloid-related imaging abnormalities with edema or effusions in 12.6%. CONCLUSIONS: Lecanemab reduced markers of amyloid in early Alzheimer\u27s disease and resulted in moderately less decline on measures of cognition and function than placebo at 18 months but was associated with adverse events. Longer trials are warranted to determine the efficacy and safety of lecanemab in early Alzheimer\u27s disease. (Funded by Eisai and Biogen; Clarity AD ClinicalTrials.gov number, NCT03887455.)

They Call for Help, But Don\u27t Always Listen: The Development of the User-Help Desk Knowledge Application Model

The IS help desk function plays a central role in boundary spanning knowledge exchanges within organizations. Help desk employees provide technical support to users in an effort to transfer knowledge and enable users to autonomously apply this knowledge in the future. However, despite their importance, little is known about the factors that affect knowledge application within this context. Adopting interpersonal influence theory, this paper develops a model that examines how dimensions of source credibility - expertise, trustworthiness, and attractiveness impact users’ knowledge application in a help desk environment. The model is tested using a sample of working adults at a large Midwestern hospital who had significant experience requesting help from an IS help desk. Results indicate that all three dimensions of source credibility predict users’ ability to apply the knowledge transferred from a help desk employee. The implications of these results are discussed

Co-occurring chronic pain and primary psychological disorders in adolescents. A scoping review.

Abstract Long‐term health conditions, whether mental or physical, often co‐occur in adolescents. For instance, adolescents with chronic pain may experience co‐occurring primary psychological disorders. In this scoping review, we determine the influence of co‐occurring chronic pain and primary psychological disorders on adolescents' functioning. A systematic search of six databases was conducted to identify articles if they were: (1) peer‐reviewed; (2) reported original findings; (3) included participants aged 11–19 years, who experienced chronic pain (i.e., pain lasting 3 months or more) and had a co‐occurring diagnosis of a primary psychological disorder; and (4) assessed functioning. Searches returned 9864 articles after the removal of duplicates. A two‐phase abstract and full‐text screening process identified two eligible articles which compared emotional functioning (n = 1) and social functioning (n = 2) between groups of adolescents with co‐occurring chronic pain and primary psychological disorders with adolescents only reporting chronic pain. Overall findings revealed no differences in social functioning, but adolescents with co‐occurring chronic pain and a primary psychological disorder (depression and anxiety) reported worse emotional functioning compared with adolescents with chronic pain alone. This review confirms the limited research on the co‐occurrence of primary psychological disorders and chronic pain in adolescents by only identifying two eligible articles exploring the co‐occurrence of chronic pain with depression, anxiety, and/or attentional disorders

Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and Other Meteorological Measurements

The lightning jump algorithm has a robust history in correlating upward trends in lightning to severe and hazardous weather occurrence. The algorithm uses the correlation between the physical principles that govern an updraft's ability to produce microphysical and kinematic conditions conducive for electrification and its role in the development of severe weather conditions. Recent work has demonstrated that the lightning jump algorithm concept holds significant promise in the operational realm, aiding in the identification of thunderstorms that have potential to produce severe or hazardous weather. However, a large amount of work still needs to be completed in spite of these positive results. The total lightning jump algorithm is not a stand-alone concept that can be used independent of other meteorological measurements, parameters, and techniques. For example, the algorithm is highly dependent upon thunderstorm tracking to build lightning histories on convective cells. Current tracking methods show that thunderstorm cell tracking is most reliable and cell histories are most accurate when radar information is incorporated with lightning data. In the absence of radar data, the cell tracking is a bit less reliable but the value added by the lightning information is much greater. For optimal application, the algorithm should be integrated with other measurements that assess storm scale properties (e.g., satellite, radar). Therefore, the recent focus of this research effort has been assessing the lightning jump's relation to thunderstorm tracking, meteorological parameters, and its potential uses in operational meteorology. Furthermore, the algorithm must be tailored for the optically-based GOES-R Geostationary Lightning Mapper (GLM), as what has been observed using Very High Frequency Lightning Mapping Array (VHF LMA) measurements will not exactly translate to what will be observed by GLM due to resolution and other instrument differences. Herein, we present some of the promising aspects and challenges encountered in utilizing objective tracking and GLM proxy data, as well as recent results that demonstrate the value added information gained by combining the lightning jump concept with traditional meteorological measurements

Design and Application of Novel Membrane Materials

Membrane technology is uniquely suited to meet the growing need for more sustainable processes due to membranes’ tailorable selectivity and energy efficiency. Efforts to further improve membrane performance and modify them for new applications have found success in academic studies with a versatile class of membranes known as mixed-matrix membranes (MMM). Mixed-matrix membranes combine the strength and controlled morphology of semicrystalline polymeric membranes with superior functionality of a separate material dispersed in the polymer matrix. The strength and toughness of the resulting membranes depends on polymer morphology, including degree of crystallinity and pore structure. Control of the membrane morphology is achieved by kinetically trapping a partially phase separated state, for example, using Nonsolvent Induced Phase Separation (NIPS) to drive liquid-liquid and solid-liquid demixing. However, the processes used to control the polymer morphology are influenced by the functional particles and can result in novel morphologies. In Chapter 2, we used a promising strategy for stably incorporating functional polymeric particles in a structural polymer matrix to investigate the role of the particles during NIPS. The interplay of functional polymeric particle loading and nonsolvent induced phase separation are examined using x-ray diffraction (to deduce the crystal morph adopted by polyvinylidene difluoride, PVDF) and scanning electron microscopy (to observe membrane morphology and the size and distribution of functional particles). We found that the interaction between nonsolvent and functional particles enables a shift in crystal phase usually not attainable with our solvent. In addition to studying the fundamentals underlying MMM formation, we investigated two applications for novel membrane materials: purification of therapeutic antibodies and size-selective particle capture. Purification of proteins for medical use requires several chromatographic steps in order to produce solutions of sufficient purity. For many years, the gold standard in the field was resin-based packed bed chromatography; however, more recently membrane chromatography has gained prevalence due to its faster processing time, lower cost, and low operating pressure. With these advantages come the drawbacks of low binding capacity and a sensitivity to the concentration of salt ions in the solution. To address these two drawbacks, we investigated the chromatographic abilities of a modified MMM, in Chapter 3, and a novel membrane material comprising an MMM-ceramic composite, in Chapter 4. We discovered that the performance of the modified MMM is dependent on crosslinker chemistry and crosslink density. Upon optimization, the modified membrane demonstrated a binding capacity consistent with the upper range of available literature values as well as reduced sensitivity to salt. In addition, the development of the novel MMM-ceramic composite enables the use of a broader range of polymer matrix compositions for membrane chromatography. Capture of pathogens from complex fluids, such as blood, has received substantial attention due to rising rates of sepsis and antibiotic resistance. In Chapter 5, we pursued the capture of pathogens from model fluids using the size-based separation capabilities of dendritic ceramic membranes. We found that interactions between the ceramic surface and the suspended particles played a significant role in membrane performance.</p