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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

UK-India Centre for Advanced Technology for Minimizing Indiscriminate Use of Antibiotics:"Exploring biology of antibiotic resistance and potential targets for early diagnosis and effective management of infectious diseases”

Rimmer, Stephen, Garg, P., MacNeil, S., Shepherd, J., Foster, S. 05 1900 (has links)
Yes / During January 15th – 17th, 2017 a group of scientists met, under the auspices of the UK-India Centre for Advanced Technology for Minimizing Indiscriminate Use of Antibiotics, to discuss the further developments and potential solutions to antimicrobial resistance. This was the third work shop under this funding stream held in Hyderabad. The presentations and outcomes of the workshop are released here. Key out comes included the need to address improved treatment and detection of TB, delivery of antimicrobial peptides, potential strategies for combating beta-lactam resistance. / Medical Research Council
332

Incidence and physiological nature of malathion resistance in four species of stored products coleoptera from grain producing states

Haliscak, Jonathan Patric January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
333

Defining mechanisms that determine the levels of drug resistance in Mycobacterium tuberculosis

Bester, Margaretha 12 1900 (has links)
Thesis (MSc (Biomedical Sciences. Molecular Biology and Human Genetics))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Varying levels of Rifampicin (RIF) resistance in closely related clinical Mycobacterium tuberculosis isolates and in vitro generated mutants question the dogma that non-synonymous single nucleotide polymorphisms in the rpoB gene are the only mechanism explaining RIF resistance. This study aimed to identify biological mechanisms that define the level of RIF resistance in two closely related clinical M. tuberculosis isolates using proteomic, transcriptomic and genomic approaches. Two dimensional electrophoresis revealed an increase in the abundance of numerous membrane proteins in response to RIF at the critical concentration of 2g/ml. Fourty-one of these proteins were identified by mass spectrometry and could be grouped according to their cellular function (Energy metabolism, degradation, biosynthesis of cofactors, metabolic groups and carriers, lipid biosynthesis, central intermediate metabolism, synthesis and modification of macromolecules, chaperone/heat shock proteins). The identification of proteins responsible for ATP synthesis (atpA and atpH) suggests an ATP requirement to combat the toxic effect of RIF. These proteins are components of the FoF1 ATP synthase an enzyme which is involved in the oxidative phosphorylation pathway that generates ATP in the cell. QRT-PCR confirmed the up regulation of the transcription of the atpA and atpH genes in response to RIF, while DNA sequencing failed to identify mutations that could define the rate of transcription. To explain our findings we proposed that RIF induces a toxic response leading to the up regulation of a number of genes. The induction of metabolic enzymes, such as the FoF1 ATP synthase provides energy to activate ATP dependant mechanisms, including membrane ABC transporters. These ABC transporters actively pump RIF out of the cell thereby lowering the intracellular concentration of RIF to below its binding concentration with the rpoB protein leading to RIF resistance. Inhibition of efflux by the efflux pump inhibitors reserpine and verapamil leads to an accumulation of RIF within the cell and concurrent binding of RIF to rpoB, leading to inhibition of transcription and cell death (ongoing research in our laboratory). Similarly, we propose that the recently identified diarylquinoline compound (TMC207) inhibit ATP synthesis, thereby depleting the energy source necessary for active efflux. This will lead to an accumulation of anti-TB drug within the cell and subsequent cell death. In summary, this study provides the first evidence to suggest that the evolution of RIF resistance is a dynamic process involving a cascade of adaptive events which leads to a bacterial growth state where hydrophobic compounds are actively extruded from the cell. This has important ramifications for the treatment of RIF resistant TB and supports the need for the development of anti-TB drugs that target both efflux and ATP synthesis to improve the treatment outcome of MDR-TB and XDR-TB. / AFRIKAANSE OPSOMMING: Verskillende vlakke van Rifampisien (RIF) weerstandigheid, in naby verwante Mycobacterium tuberculosis kliniese isolate en in vitro mutante, bevraagteken die dogma dat nie-sinonieme enkel nukleotied polimorfismes in die rpoB geen die enigste verklaarbare meganisme vir RIF weerstandigheid is. Die doel van hierdie studie was om deur 'n proteomiese, transkriptomiese en genomiese benadering, biologiese meganismes te identifiseer wat die vlakke van RIF weerstandigheid in twee naby verwante kliniese M. tuberculosis isolate bepaal. Twee dimensionele elektroferese het gevind dat daar 'n verhoging in die hoeveelheid van verskeie proteïne is wanneer die isolate aan RIF by die 'n kritiese konsentrasie van 2μg/ml blootgestel is. Massa spektrometrie het 41 van hierdie proteine geïdentifiseer en die proteïne kan gegroepeer word in verskeie sellulêre funksies (Energie metabolism, degradering, biosintese van kofaktore, metaboliese groepe en draers, lipied biosintese, sentrale intemediêre metabolisme, sintese en modifisering van makromolekules, en “chaperone/heat shock” proteine). Die identifisering van proteïne verantwoordlik vir ATP sintese (atpA en atpH) stel voor dat ATP belangrik is om die toksiese effek van RIF te ontwyk. Hierdie proteïne is komponente van die FoF1 ATP sintase ensiem wat betrokke is in die oksidatiewe fosforilerings pad en wat lei tot die generering van ATP in die sel. Kwantitatiewe QRT-PCR het bevestig dat hierdie gene, atpA en atpH, opgereguleer word nadat die bakterium aan RIF blootgestel is. In teen deel kon DNA volgorde bepaling nie mutasies identifiseer wat die verandering in geen transkripsie kon verklaar nie. Om ons bevindings te verduidelik, stel ons voor dat RIF 'n toksiese effek in die sel induseer wat lei tot die opregulering van verskeie gene. Die indusering van metaboliese ensieme, soos die FoF1 ATP sintase, voorsien energie om ATP afhanklike meganismes, insluitende membraan ABC transporters, te aktiveer. Hierdie ABC transporters pomp RIF aktief uit die sel, wat daarvolgens die intrasellulêre konsentrasie van RIF verlaag tot 'n konsentrasie laer as die bindings konsentrasie met die rpoB protein en gevolglik lei tot weerstandigheid. Die onderdrukking van membraan pompe wat RIF uit die sel pomp deur middels soos reserpine en verapamil sal aanleiding gee lei tot akkumulering van RIF in die sel. Die verhoogde RIF in die sel versoorsaak dat RIF aan die rpoB protein gebind bly sodat dit transkripsie inhibeer, wat dan aanleiding gee tot seldood. (voortgesette navorsing in ons laboratorium). Soortgelyk, stel ons voor dat die onlangs geïdentifiseerde dairylquinoline verbinding (TMC207) ATP sintese inhibeer en daarvolgens die energie bron uitput wat noodsaaklik is vir aktiewe uitpomp van RIF. Dit sal aanleiding gee tot die ophoping van RIF in die sel en gevolglik lei tot seldood. In opsomming, hierdie studie voorsien die eerste bewys wat voorstel dat die evolusie van RIF weerstandighied 'n dinamiese proses is. Dit sluit 'n kaskade van aanpasbare gebeurtenisse in wat lei tot 'n bakteriële groei fase waar hidrofobiese verbindings aktief uit die sel gedryf word. Dit het rampspoedige gevolge vir die behandeling van RIF weerstandige TB en ondersteun die noodsaaklikheid om teen-TB middels te ontwikkel wat beide effluks pompe en ATP sintese teiken om die uikoms van behandeling vir MDR-TB en XDR-TB te verbeter.
334

Factors Affecting Consumers' Resistance : A Study of Smartphones

Khan, Kamran, Hyunwoo, Kim January 2009 (has links)
<p> </p><p>Background: In mobile phone industry, Smartphones are gaining popularity as an effective communication tool, providing users with “Smart” functionalities of both cell-phone and Personal Digital Assistant (PDA). Experts in mobile industry expect that smartphones are going to be dominant in mobile phone market. However, Smartphone industry is facing a different reality, with its declining sales and less market share, forcing research companies (Gartner, Canalys, etc.) to change their expectations. This situation leads us to another important and often ignored perspective of innovation challenges, i.e. consumers' resistance; as consumers' adoption and purchase decision makes a significant difference in the success of innovative products.</p><p>Problem: Innovation has been called as a key factor for companies to survive and grow in the long run, especially in the dynamic & complex markets and uncertain economic circumstances. Despite the successful outcome of innovations, inhibition or delay in the diffusion of innovation may translate this success into market failure, where resistance has been called as one of the main reasons for inhibiting or delaying the innovation diffusion. Consumers adoption of innovation depend upon several factors: the most important of which are specified as consumers’ characteristics (psychological characteristics of consumers; how they view the innovativeness with respect to that particular product), and the innovation characteristics (outcome and effects of innovation). Past research on innovation & consumers characteristics represents good relationship among the innovation/consumers factors and the adoption/implementation of that innovation by consumers.</p><p>Purpose: The purpose of this study is to identify and analyze the relationship between consumers' resistance and different factors from innovation and consumers' characteristics. Thereafter, important factors are identified that mainly affect/determine consumers' resistance to smartphones. Moreover, the inter-relationship (correlation) among the selected factors is found out, to know the affects of each factor on other factors.</p><p>Method: Following abductive approach, confirmatory factor analysis has been done on pre-test questionnaires to test, improve, and verify the constructs (variables/questions) for measuring the hypothesized factors. A theoretical model has been proposed from the hypotheses; and Structural Equation Modeling has been applied, where results are estimated through Partial Least Square and AMOS approaches, using a sample of 330 respondents from Sweden. SmartPLS software has been used to estimate results, thereafter, AMOS has been used to check and verify the results. Almost same results have been derived from both approaches, while results from PLS are found as more satisfactory.</p><p>Conclusions: Five out of eight hypotheses have been supported by our empirical data, where H1 i.e. relative advantage, H3 i.e. complexity, and H4 i.e. perceived risk, are from innovation characteristics, while H6 i.e. motivation, and H7 i.e. „favorable attitude towards existing products‟ are from consumers' characteristics. Motivation, Complexity, Relative Advantage, and Perceived Risk are found as important factors (as per their order) that affect/determine consumers' resistance to smartphones. Relative Advantage & Motivation are found as positively correlated, and Perceived Risk & Complexity are found as positively correlated. Negative correlation has been found between Perceived Risk and relative advantage. Similarly, negative correlation has been found between motivation and complexity. The proposed model of consumers resistance to smartphones shows an acceptable goodness of fit, where 65% (R-square value) of variation in consumers resistance is caused/explained by the hypothesized factors.</p><p> </p> / The Presentation (Defense) has been attended by Cecilia Bjursel instead of our supervisor Desalegn Abraha.
335

Effects of Resistance Training on Insulin Sensitivity and Markers of Inflammation in Rheumatoid Arthritis Patients Treated with Remicade

Gates, Donald L. January 2009 (has links)
INTRODUCTION Rheumatoid arthritis (RA) is a disease of chronic inflammation in the joints and organs. RA patients exhibit 4-fold increased incidence of CVD, increased prevalence of insulin resistance (IR) and increased mortality. Aerobic and resistance training (RT) programs have been suggested for the management of RA symptoms and reduction of comorbidities, including insulin resistance. Exercise has been shown by recent evidence to be safe and beneficial in RA patients. RT has been documented to improve inflammation and insulin sensitivity. The present study was undertaken to examine the impact of a sixteen week intensive training regimen on disease status, body composition, markers of inflammation and indicators of insulin resistance in RA patients undergoing infliximab therapy, a potent RA treatment.METHODS30 RA patients were randomized into exercise (EX) or control (C) groups. EX patients underwent a 16-week supervised, intensive, progressive and individualized resistance training regimen. Participants were monitored by professional fitness trainers during all exercise sessions. Subjects were assessed prior to and after intervention. Assessments included disease status, strength and functional testing, anthropometrical and body composition analysis, analysis of markers of inflammation and assessment of insulin sensitivity.RESULTS EX subjects significantly increased in strength and functional ability without worsening of disease state, and increased lean mass from baseline. Fat mass was significantly reduced in EX. Glucose and resistin levels increased significantly following EX intervention. Mean IR was unchanged, but EX subjects with elevated IR did show improvement following training. Regression analysis indicates duration of infliximab therapy to be correlated with improved insulin sensitivity.CONCLUSIONS RA patients taking infliximab tolerated an intensive resistance training program. Participants increased strength and lean mass while decreasing fat mass and displayed improved functional capacity. Disease status was not worsened by the regimen. Though the mean measure of IR did not improve, those patients with the most adverse scores did show improvement following the intervention. Furthermore, regression analysis indicates that infliximab treatment duration was linked to reduced IR. In conclusion, resistance training improved strength and functional ability in RA patients taking infliximab without disease degradation, and may help reduce IR in those patients with elevated resistance.
336

Glyphosate resistance in kochia

Godar, Amar Singh January 1900 (has links)
Doctor of Philosophy / Department of Agronomy / Phillip W. Stahlman / Kochia [Kochia scoparia (L.) Schrad.] is a weed of great economic importance in the Great Plains and western United States and Canada. This weed is prone to evolving resistance to herbicides. Glyphosate is the most widely used herbicide in glyphosate-resistant crops and chemical fallow, and is extremely valuable to crop production. Anecdotal reports of kochia control failure with glyphosate in western Kansas arose during the mid-2000’s. The objectives of this research were to (1) confirm and characterize glyphosate resistance in kochia and measure its impact in western Kansas, (2) gather information on grower weed management practices before and since glyphosate resistance in kochia was confirmed, and (3) determine if altered absorption and translocation of glyphosate contributes to glyphosate resistance in kochia. Dose-response studies on greenhouse and outdoor grown plants, and shikimate accumulation assays confirmed one kochia population collected in 2007 and eight populations collected in 2010 tolerated three- to eleven-times more glyphosate compared to a known glyphosate-susceptible (GS) population. Furthermore, 40 kochia populations collected in 2012 showed varied response, from slightly elevated tolerance to resistance to 0.84 kg ae ha-1 glyphosate. Further analysis suggested these populations were at different stages of resistance evolution. An online survey revealed that growers increased glyphosate use rate and application frequency, but decreased exclusive use of glyphosate and diversified weed management practices during post- compared to pre-glyphosate confirmation periods. Most survey respondents reported presence of glyphosate-resistant (GR) kochia in at least in few fields, and half reported GR kochia in a majority of fields. Thus, together with the resistance confirmation studies, it is estimated that at least one-third of western Kansas kochia populations have evolved resistance to glyphosate. Nominal differences in absorption and translocation of 14C-glyphosate observed between GS and GR kochia populations likely do not contribute to differential response of these populations to glyphosate. Glyphosate-resistant kochia has become widespread in western Kansas in a short period of time. Use of weed resistance best management practices (BMP) is imperative to sustain the utility of glyphosate in the region.
337

Low flow hydraulics in rivers for environmental applications in South Africa

Jordanova, Angelina Alekseevna 24 March 2009 (has links)
Implementation of the National Water Act in South Africa requires that an ecological Reserve be determined for all significant resources. The ecological Reserve determination is the estimation of the amount of water required to maintain the system in a particular ecological condition. Because aquatic habitats are defined in terms of local hydraulic variables rather than amounts of water, hydraulic analysis provides a crucial link in relating hydrological conditions and river ecosystem integrity. Over the last decade, considerable effort has been devoted to developing hydraulics for the Reserve determination. The hydraulics needs for Reserve determination are primarily for low flow analysis, and appropriate methods still need to be developed. This thesis deals with hydraulics under low flow conditions. Its emphasis is on developing appropriate methods for describing the hydraulic characteristics of South African rivers under conditions of low discharge, and the influence of vegetation and large bed roughness. The following methods have been developed: · A new equation for prediction of overall flow resistance under large-scale roughness, and a new approach for estimation of intermediate-scale roughness resistance that distinguishes the influences of large and intermediate scale roughness components. · Prediction methods for velocity distributions with large roughness elements. Under low flows, rocks and boulders may control the local velocity and depth distributions. Distributions of velocities and depth are related to rapidly spatially varied flow caused by the boundary geometry rather than flow resistance phenomena. With increasing discharge, the multiple local controls become submerged and the flow tends towards a resistance controlled condition. Available information addressing the distinction between resistance controlled and multiple local controls conditions is limited. This thesis contributes to understanding the transformation between multiple local controls and the resistance controlled conditions. · Practical conveyance prediction methods for three situations pertaining to the occurrence of vegetation in rivers and wetlands. In-channel and riparian vegetation makes an important contribution to the creation of physical habitats for aquatic animals, but also has significant effects on flow resistances that need to be predicted.
338

The fitness costs of drug resistance mutations in Mycobacteria

Koch, Anastasia Sideris 17 January 2012 (has links)
MSc., Faculty of Science, University of the Witwatersrand, 2011 / The increasing emergence of drug-resistant pathogens poses a major threat to public health. Although influenced by multiple factors, resistance is often associated with mutations in drug target-encoding or associated genes. The potential fitness cost of such resistance mutations is, in turn, a key determinant of the spread of drug-resistant strains. Rifampicin (RIF) is a frontline anti-tuberculosis agent that targets the rpoB-encoded β-subunit of the DNA-dependent RNA polymerase (RNAP). RIF resistance (RIFR) maps primarily to mutations in rpoB that might be expected to affect transcription and so the ability of the organism to cause disease. Accordingly, numerous studies have assessed the impact of RIFR on key fitness indicators in pathogens including Mycobacterium tuberculosis (MTB). In contrast, the specific consequences of RIFR for bacterial physiology remain poorly understood. Notably, previous studies of the effects of RIFR-associated rpoB mutations on mycobacterial physiology have been conducted using strains generated by RIF exposure, without accounting for the potential impact of second-site mutations that may compensate for fitness costs or contribute to drug resistance. In this study, site-directed mutagenesis and allelic exchange were employed to generate a panel of M. smegmatis (MSM) strains containing clinically-relevant RIFR-associated point mutations. Importantly, this methodology enables the introduction of rpoB mutations into defined strain backgrounds in the complete absence of RIF. Using this approach, we constructed “RIF naive” MSM rpoB mutant strains carrying either an S531L or H526Y mutation. The resulting mutants were 100-fold less susceptible to RIF than the isogenic, parental strain. Notably, the inclusion of selected efflux inhibitors in susceptibility assays had little impact on mutant susceptibility to RIF. In contrast, restoration of the wild-type allele returned the observed susceptibility to parental levels, thereby providing strong evidence of the sufficiency of a single rpoB mutation for clinical RIFR in mycobacteria. Competitive growth assays utilizing the S531L mutant and the parental strain exposed a growth defect for the S531L mutant. However, discriminating between wild-type and mutant rpoB strains proved a significant technical challenge, again highlighting the difficulties associated with inferring in vivo fitness from in vitro assays conducted under a limited number of different conditions. In summary, our results suggest the benefit of a deeper exploration of the physiological and fitness implications of RIFR-associated mutations. In addition, in coupling a system which enables an evaluation of the physiological consequences of drug resistance-associated mutations with evolutionary analyses, we provide preliminary evidence of the benefits of a multipronged approach to elucidating the physiological implications of drug resistance in MTB.
339

In vitro transport profile of antiepileptic drugs by human P-glycoprotein and functional evaluation of human MDR1 polymorphisms on transport activity. / CUHK electronic theses & dissertations collection

January 2011 (has links)
Conclusions: CETA may be a more sensitive system than the bi-directional transport assay to detect transport of drugs with high passive diffusion across the BBB. We conclude that PHT, PB, OXC, ESL, CBZ-E, S-LC, and LCM, but not ESM, CBZ, RPM, ZNS, and PGB, are transported by human Pgp. These data suggest that resistance to PHT, PB, ESL, OXC and LCM might be attributed to increased efflux function of Pgp because they or their active metabolites are Pgp substrates. The CTC haplotype exhibited increased directional transport activity by Pgp. The effects of MDR1 polymorphisms on AED transport may provide a molecular explanation of the association between the polymorphisms and pharmacoresistance. This knowledge may help guide the design of genetic-based individualized therapy of epilepsy. / Methods: Stable transfected clones of human MDR1 haplotypes combining 1236C>T, 2677G>T/A, and 3435C>T in LLC-PK1 cells were established and validated. The expression level and localization of Pgp were measured. Bi-directional transport assays or concentration equilibrium transport assays (CETA) were performed by using MDR1-transfected and non-transfected cells to determine the substrate status of the following AEDs: phenytoin (PHT), phenobarbital (PB), ethosuximide (ESM), carbamazepine (CBZ), eslicarbazepine acetate (ESL), oxcarbazepine (OXC), (S)-licarbazepine (S-LC), carbamazepine-10,11-epoxide (CBZ-E), rufinamide (RFM), lacosamide (LCM), zonisamide (ZNS), and pregabalin (PGB). LLC-PK1 cells transfected with MDR1 variants were used to evaluate the effects of MDR1 polymorphisms on transport activity of AEDs in CETA. / Purpose: Epilepsy is a major neurological disorder, affecting more than 50 million people worldwide. Antiepileptic drugs (AEDs) do not effectively treat 30--40% of patients. Export of AEDs by P-glycoprotein (Pgp, ABCB1, or MDR1), which is overexpressed in the blood-brain barrier in drug-resistant patients, may be a mechanism for resistance to AEDs. Single nucleotide polymorphisms (SNPs) 1236C>T, 2677G>T and 3435C>T have been associated with drug-resistant epilepsy and were sometimes found to have effects on Pgp activities. But whether (or which) AEDs are transported by Pgp remains unclear, and there is no direct evidence showing that polymorphisms affect the transport of AEDs by Pgp. Therefore, we propose to use monolayers of cells transfected with the MDR1 variants to investigate 1) which AEDs are substrates for Pgp; and 2) the effect of MDR1 polymorphisms (1236C>T, 2677G>T, and 3435C>T) on AED transport. / Results: In CETA, PHT, PB, and LCM were transported by MDR1-transfected cells from basolateral to apical sides, while RFM, ZNS, PGB and ESM were not transported. Pgp did not transport CBZ, but did transport its active metabolite CBZ-E. Pgp also pumped ESL, OXC, and their active metabolite S-LC. The transport of these drugs can be completely blocked by Pgp inhibitor verapamil or tariquidar. In bi-directional transport assays, the Papp for the basolateral to apical direction in MDR1-transfected cells was significantly higher than in non-transfected cells for PHT, OXC, ESL, and S-LC, and not for PB, CBZ-E, CBZ, or ESM. / To compare the extent of basolateral-to-apical transport efficiency of different variants, we calculated the amount of the transported drugs divided by expression level of MDR1 in the apical chamber for each variant. In the G418 selection condition, compared with reference haplotype CGC, the CTC haplotype increased Pgp activity to transport OXC and ESL, while the CGT and CTT haplotypes did not significantly affect Pgp function. In the vincristine sulfate selection condition, compared with CGC, the haplotype CTT decreased Pgp activity, while other haplotypes, including CGC, CGT, CAC, CTC, TGC, TGT, TTT, and TTC, did not affect function. Selection by vincristine sulfate may raise expression of Pgp and eliminate differences among the variants. / Zhang, Chunbo. / Advisers: Vincent Hon Leung Lee; Lawrence William Baum; Zhong Zuo; Patrick Kwok Leung Kwan. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 192-221). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
340

Characterizing the Entry Resistance of Smoke Detectors

Ierardi, James Arthur 11 May 2005 (has links)
Entry resistance in smoke detectors was investigated using experimental and analytical approaches. The experimental work consisted of measuring velocity inside the sensing chamber of smoke detectors with a two-component Laser Doppler Velocimeter and exposing addressable smoke detectors to four different aerosol sources. The velocity measurements and exposure tests were performed in NIST's Fire Emulator / Detector Evaluator under steady state flow conditions in the range of 0.08 to 0.52 m/s. The addressable detectors were a photoelectric and an ionization detector. A specially constructed rectangular detector model was also used for the interior velocity measurements in order to have geometry compatible with numerical approaches, such as computational fluid dynamics modeling or a two-dimensional analytical solution. The experimental data was used to investigate the fluid mechanics and mass transport processes in the entry resistance problem. An inlet velocity boundary condition was developed for the smoke detectors evaluated in this study by relating the external velocity and detector geometry to the internal velocity by way of a resistance factor. Data from the exposure tests was then used to characterize the nature of aerosol entry lag and sensor response. The time to alarm for specific alarm points was determined in addition to performing an exponential curve fit to obtain a characteristic response time. A mass transport model for smoke detector response was developed and solved numerically. The mass transport model was used to simulate the response time data collected in the experimental portion of this study and was found, in general, to underestimate the measured response time by up to 20 seconds. However, in the context of wastebasket fire scenario the amount of underprediction in the model is 5 seconds or less which is within the typically polling interval time of 5 to 10 seconds for an addressable system. Therefore, the mass transport model results developed using this proposed engineering framework show promise and are within the expected uncertainty of practical fire protection engineering design situations.

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