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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.
221

In the middle : on sourcing from China and the role of the intermediary

Balkow, Jenny January 2012 (has links)
In the past three decades China’s rapid transition from a closed economy to become the factory of the world has astonished economists all over the world. Surveys among sourcing practitioners show that China is the most interesting market for sourcing and research points to lower costs as the main reason.This dissertation is an exploratory study of the role of the intermediary for Swedish small and medium sized enterprises (SMEs) that source from China. Three questions are discussed. The first question concerns why Swedish SMEs choose to source from China. Although costs are a major factor for the companies, it is usually other triggers that cause the change in strategy, such as management interest or pressure from a large customer. The second research question concerns how Swedish SMEs choose to source from China and how the role of the intermediary is related to this process. The study shows that finding a good supplier is not difficult. The companies use informal channels, references and sometimes unorthodox methods such as following the supplier of the raw material to find suppliers that deliver high quality goods. The problem is however to maintain a steady quality and on time delivery which is why intermediaries are introduced late in the relationship. The cases in this study show example of five different intermediated strategies; Direct, Service,Traditional, RepO and FICE/WFOE. The traditional intermediated strategy is the only strategy where there is little or no relation between buyer and supplier, whereas the other four strategies involve different degrees of interaction between all three actors in the dyad; the buyer, the supplier and the intermediary.The third research question concerned the role of the intermediary. The study shows that the respondents are influenced by their structural view on what role the different forms of intermediaries may take. Although the respondents discuss the importance of having a long-term view on the relationship with the supplier they continuously allow intermediaries to enter the relationship on a short-term basis for quality control. These quality control centers (QC) commonly work on a fixed commission based on services that has to be specified. When the buyers are trying to change their strategy to look for an intermediary with higher involvement they usually turn to internal intermediaries (i.e. subsidiaries). When deciding on a long term intermediary the buyer usually looks for competences that supplement their own knowledge – that is Chinese language, good knowledge of the Chinese market but also technological competence. What the western owned intermediaries in China stresses however is the need to find intermediaries to supplement the suppliers’ competences, so that they are able to translate the needs of the buyer’s customer and becomes a physical reminder that they are sent from the buyer. The case of QC, shows that if a company let the relationship with the intermediary develop through interaction they can become just as involved.The study is based on interviews with key informants at Swedish SMEs andat different types of intermediaries in China. The empirical data are presented infive themes developed through an iterative process of theoretical studies anddata collection. The first two themes are directly related to the first tworesearch questions. The third theme focuses on the sourcing process andactivities of four small Swedish design companies. The fourth theme displayshow the intermediaries in China discuss their role. Finally, the fifth theme pictures the supply chain of one focal company at five points in time when they are in the process of changing their supply chain to increase transparency. / Disputationen sker fredagen den 30 mars kl. 13.00 i sal B1014 på Internationella Handelshögskolan, Högskolan i Jönköping
222

A DISTRIBUTED NETWORK ARCHITECTURE FOR PC-BASED TELEMETRY SYSTEMS

Windingland, Kim L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The ever-increasing power of PC hardware combined with the new operating systems available make the PC an excellent platform for a telemetry system. For applications that require multiple users or more processing power than a single PC, a network of PCs can be used to distribute data acquisition and processing tasks. The focus of this paper is on a distributed network approach to solving telemetry test applications. This approach maximizes the flexibility and expandability of the system while keeping the initial capital equipment expenditure low.
223

The spirit of Sparta conquers the skies

Riedel, Henrik G. A. H 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The emergence of low cost airlines (LCAs) has attracted attention from passengers, competitors, the public, and researchers alike. It seems prodigious that LCAs prosper in today's time of economic downturn and are therefore able to counter the industry's trend. lATA's member airlines have accumulated losses of $31 billion since the beginning of the new millennium. Furthermore, industry icons such as American Airlines and British Airways are fighting for survival while some, namely Air Canada, are on the edge of bankruptcy: a fate which others, like Sabena, have not been able to escape. However, the low cost business model has triumphantly entered the aviation market since the deregulation of the markets in the U.S. in 1978. Low cost airlines like Southwest Airlines and Ryanair not only achieve double-digit profit margins, but also have the highest market capitalisation of the industry. This thesis examines the reason for the success of LCAs in the U.S. and EU. LCAs operate with a much lower cost base than most carriers, especially the major hut-and-spoke (H&S) airlines. The low cost business model aims at increasing both aircraft and staff productivity. It also simplifies the sequence of operations workflow and pricing structure. The thesis gives special consideration to the cost structure of LCAs. The advantages of LCAs lie within the areas such as labour, seat density, and distribution. The second objective of this thesis is to evaluate the development of LCAs and consider the implications for the European transport industry. Whereas American LCAs have operated for more than twenty-five years, the boom of their European counterparts did not commence until the end of the 1990s. Ryanair and easyJet have growth rates of more than thirty percent. The author agrees with the expectations of aviation experts that LCAs will grow until they serve approximately a quarter of the market; hence, the business model of low cost is sustainable. However, only three to four low cost airlines will survive the fierce competition in Europe. / AFRIKAANSE OPSOMMING: Die dringendheid van lae koste lugrederye (LKL'e) het die aandag getrek van passasiers, mededingers, die publiek en navorsers. Dit is vreemd dat LKL'e floreer in die huidige ekonomiese afswaai en gevolglik die tendens van die industrie teenwerk. Lugrederye, wat lid is van "lATA" , het sedert die begin van die eeu verliese gelei van 31 biljoen dollar. Daar teenoor is industriele ikone soos die Amerikaanse en Britse lugdienste (American Airlines and British Airways) besig om te veg vir oorlewing, terwyl ander soos die Kanadese lugdiens (Air Canada) op die grens van bankrotskap is: 'n ramp wat sommige soos Sabena nie kon vryspring nie. Sedert die deregulering van die lugvaart in die VSA in 1978 het die lae koste besigheidsmodel egter die mark triomfanlik betree. Lae koste lugrederye soos SuidWes lugdiens en Ryanair ervaar nie alleen dubbel-syfer wins-marges nie, maar het ook die hoogste mark-kapitalisasie in die industrie. Hierdie verhandeling ondersoek die redes vir die sukses van LKL'e in die V.SA en E.U. LKL'e werk teen 'n baie laer koste basis as die meeste vervoerders, veral die belangrikste "hub-and-spoke" lugrederye. Die doel van die lae koste besigheidsmodel is om beide die vliegtuie en die personeel se produktiwiteit te verhoog. Dit vereenvoudig ook die volgorde van prosedures, werkvloei en prysstruktuur. Hierdie verhandeling gee spesiale aandag aan die kostestruktuur van LKL'e. Die voordele van LKL'e lê op die gebied van arbeid, sitplekplasing en verspreiding. Die tweede doel van hierdie verhandeling is om die ontwikkeling van LKL'e te evalueer en te kyk na die invloed op die Europese vervoer-industrie. Die Amerikaanse LKL'e word reeds vir meer as vyf-en-twintig jaar bedryf terwyl hulle Europese eweknie nie 'n opswaai voor die einde van die 1990's ervaar het nie. Ryanair en easy Jet het 'n groei getoon van meer as 30%. Die argument is dat volgens lugvaartkundiges die LKL'e sal groei totdat dit ongeveer 'n kwart van die mark bedien; daarom sal die lae koste model die beste oorleef. Nogtans sal slegs drie of vier van die lae koste lugrederye egter die hewige kompetisie in Europa oorleef.
224

Development of non-vacuum and low-cost techniques for Cu(In, Ga)(Se, S)2 thin film solar cell processing

Hibberd, Christopher J. January 2009 (has links)
Solar photovoltaic modules provide clean electricity from sunlight but will not be able to compete on an open market until the cost of the electricity they produce is comparable to that produced by traditional methods. At present, modules based on crystalline silicon wafer solar cells account for nearly 90% of photovoltaic production capacity. However, it is anticipated that the ultimate cost reduction achievable for crystalline silicon solar cell production will be somewhat limited and that thin film solar cells may offer a cheaper alternative in the long term. The highest energy conversion efficiencies reported for thin film solar cells have been for devices based around chalcopyrite Cu(In, Ga)(Se, S)2 photovoltaic absorbers. The most efficient Cu(In, Ga)(Se, S)2 solar cells contain absorber layers deposited by vacuum co-evaporation of the elements. However, the cost of ownership of large area vacuum evaporation technology is high and may be a limiting factor in the cost reductions achievable for Cu(In, Ga)(Se, S)2 based solar cells. Therefore, many alternative deposition methods are under investigation. Despite almost thirty companies being in the process of commercialising these technologies there is no consensus as to which deposition method will lead to the most cost effective product. Non-vacuum deposition techniques involving powders and chemical solutions potentially offer significant reductions in the cost of Cu(In, Ga)(Se, S)2 absorber layer deposition as compared to their vacuum counterparts. A wide range of such approaches has been investigated for thirty years and the gap between the world record Cu(In, Ga)(Se, S)2 solar cell and the best devices containing non-vacuum deposited absorber layers has closed significantly in recent years. Nevertheless, no one technique has demonstrated its superiority and the best results are still achieved with some of the most complex approaches. The work presented here involved the development and investigation of a new process for performing one of the stages of non-vacuum deposition of Cu(In, Ga)(Se, S)2 absorber layers. The new process incorporates copper into an initial Group III-VI precursor layer, e.g. indium gallium selenide, through an ion exchange reaction performed in solution. The ion exchange reaction requires only very simple, low-cost equipment and proceeds at temperatures over 1000°C lower than required for the evaporation of Cu under vacuum. In the new process, indium (gallium) selenide initial precursor layers are immersed in solutions containing Cu ions. During immersion an exchange reaction occurs and Cu ions from the solution exchange places with Group III ions in the layer. This leads to the formation of an intimately bonded, laterally homogeneous copper selenide – indium (gallium) selenide modified precursor layer with the same morphology as the initial precursor. These modified precursor layers were converted to single phase chalcopyrite CuInSe2 and Cu(In, Ga)Se2 by annealing with Se in a tube furnace system. Investigation of the annealing treatment revealed that a series of phase transformations, beginning at low temperature, lead to chalcopyrite formation. Control of the timing of the Se supply was demonstrated to prevent reactions that were deemed detrimental to the morphology of the resulting chalcopyrite layers. When vacuum evaporated indium (gallium) selenide layers were used as initial precursors, solar cells produced from the absorber layers exhibited energy conversion efficiencies of up to 4%. While these results are considered promising, the devices were characterised by very low open circuit voltages and parallel resistances. Rapid thermal processing was applied to the modified precursor layers in an attempt to further improve their conversion into chalcopyrite material. Despite only a small number of solar cells being fabricated using rapid thermal processing, improvements in open circuit voltage of close to 150mV were achieved. However, due to increases in series resistance and reductions in current collection only small increases in solar cell efficiency were recorded. Rapid thermal processing was also used to demonstrate synthesis of single phase CuInS2 from modified precursor layers based on non-vacuum deposited indium sulphide. Non-vacuum deposition methods provide many opportunities for the incorporation of undesirable impurities into the deposited layers. Analysis of the precursor layers developed during this work revealed that alkali atoms from the complexant used in the ion exchange baths are incorporated into the precursor layers alongside the Cu. Alkali atoms exhibit pronounced electronic and structural effects on Cu(In, Ga)Se2 layers and are beneficial in low concentrations. However, excess alkali atoms are detrimental to Cu(In, Ga)Se2 solar cell performance and the problems encountered with cells produced here are consistent with the effects reported in the literature for excess alkali incorporation. It is therefore expected that further improvements in solar cell efficiency might be achieved following reformulation of the ion exchange bath chemistry.
225

Compact and broadband antenna system at UHF

Riauka, Nerijus January 2010 (has links)
The aim of this research was to study a novel, broadband, low cost, low profile and a high-medium gain antenna in the UHF band. This has been achieved through numerical modelling, theoretical investigation and physical measurements. In this study two commercially available antenna systems are investigated in order to compare and establish potential deficiencies in the UHF antenna systems. A number of disadvantages are resolved within a novel antenna system design. The parametric study is performed for each element of the novel antenna system in order to optimise its overall performance. The indoor and outdoor measurements have been carried out in house, in order to validate the predicted results. The novel antenna system is compared to the most popular and commercially available UHF antenna systems. The study demonstrates that the novel antenna system has clear advantages such as broadband, balanced, compact and low cost when compared to the commercial antenna designs studied here. The comparison of the manufacturers' data to the measured results shows a good match, validating the outdoor measurements technique used in this research.
226

A Kalman Filter Based Attitude Heading Reference System Using a Low Cost Inertial Measurement Unit

Leccadito, Matthew 30 July 2013 (has links)
This paper describes, the development of a sensor fusion algorithm-based Kalman lter ar- chitecture, in combination with a low cost Inertial Measurement Unit (IMU) for an Attitude Heading Reference System (AHRS). A low cost IMU takes advantage of the use of MEMS technology enabling cheap, compact, low grade sensors. The use of low cost IMUs is primar- ily targeted towards Unmanned Aerial Vehicle (UAV) applications due to the requirements for small package size, light weight, and low energy consumption. The high dynamics nature of smaller airframes, coupled with the typical vibration induced noise of UAVs require an e cient, reliable, and robust AHRS for vehicle control. To eliminate the singularities at 90 on the pitch and roll axes, and to keep the computational e ciency high, quaternions are used for state attitude representation.
227

Paste deposition modelling : deconstructing the additive manufacturing process : development of novel multi-material tools and techniques for craft practitioners

Schunemann, Esteban January 2015 (has links)
A novel paste deposition process was developed to widen the range of possible materials and applications. This experimental process developed an increasingly complex series of additive manufacturing machines, resulting in new combinations of novel materials and deposition paths without sacrificing many of the design freedoms inherit in the craft process. The investigation made use of open-source software together with an approach to programming user originated infill geometries to form structural parts, differing from the somewhat automated processing by 'closed' commercial RP systems. A series of experimental trials were conducted to test a range of candidate materials and machines which might be suitable for the PDM process. The combination of process and materials were trailed and validated using a series of themed case studies including medical, food industry and jewellery. Some of the object created great interest and even, in the case of the jewellery items, won awards. Further evidence of the commercial validity was evidenced through a collaborative partnership resulting in the development of a commercial version of the experimental system called Newton3D. A number of exciting potential future directions having been opened up by this project including silicone fabrics, bio material deposition and inclusive software development for user originated infills and structures.
228

Painéis de vedação de concreto moldados in loco: avaliação de desempenho térmico e desenvolvimento de concretos / Cast-in-place monolithic panels of concrete: evaluation of thermal performance and development of concrete

Sacht, Helenice Maria 28 August 2008 (has links)
A carência habitacional é atualmente um dos maiores desafios urbanos para as políticas públicas das cidades brasileiras e deve impulsionar a busca de soluções tecnológicas para o desenvolvimento de habitações com baixo custo e desempenho satisfatório. Nesse contexto se insere o sistema construtivo de painéis monolíticos de concreto moldados in loco. Nesta pesquisa apresenta-se uma proposta de desenvolvimento de concretos destinados ao sistema construtivo de painéis monolíticos moldados in loco, tendo como referencial, além dos requisitos técnicos de trabalhabilidade, resistência mecânica e durabilidade, a influência dos painéis no desempenho térmico das habitações. Com isso, o desenvolvimento dos concretos assim como a definição de espessura do painel de vedação foi realizado, considerando as particularidades das oito diferentes zonas bioclimáticas brasileiras e as tipologias construtivas adotadas pela Companhia de Desenvolvimento Habitacional e Urbano (CDHU) e Caixa Econômica Federal (CEF). Por meio de simulações computacionais do desempenho térmico de edificações térreas (com laje plana, com laje inclinada e sem laje) e multipavimentos (cobertura e segundo pavimento), avaliaram-se as espessuras dos painéis (8, 10 e 12 cm) e as massas específicas dos concretos (1600, 1800, 2000, 2200 e 2400 kg/m³) adequadas em relação às características climáticas das localidades analisadas, utilizando como parâmetro a norma NBR 15575 Edifícios habitacionais de até cinco pavimentos - Desempenho, da Associação Brasileira de Normas Técnicas. A partir da avaliação do desempenho térmico das tipologias selecionadas, dentre os concretos e as espessuras de painéis analisadas, observou-se que as tipologias com painéis de concreto com massa específica de 2400 kg/m³ e com espessura de 12 cm foram as que apresentaram os melhores resultados para as oito regiões bioclimáticas analisadas. / Nowadays, the lack of housing has been one of the biggest urban challenges to the Brazilian public policies and should impel the search for technological solutions by the development of housings with low-cost and satisfactory performance. In this context is the constructive system of cast-in-place monolithic panels of concrete. This dissertation presents a proposal for the development of concretes destined to the system having the technical requirements of workability, mechanical resistance and durability, and the influence of the panels peculiarities on the thermal performance of the housings as reference. Herewith, the development of concretes as well as the panels thicknesses definition has been realized, considering the particularities of the eight different Brazilian climate zones, and the constructive typologies used by the Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo (CDHU) and Caixa Econômica Federal (CEF). By means of computational simulations of thermal performance of one-storey (with plane and inclined slabs, and without slab) and multi-storey (last and second floors) constructive typologies, the suitable panels thicknesses (8, 10 and 12 cm) and concretes densities (1600, 1800, 2000, 2200 and 2400 kg/m³) in relation to the climatic characteristics of the analyzed places were determined, having the standard NBR 15575 Residential buildings up to five storied Performace of the Associação Brasileira de Normas Técnicas as parameter. Starting from the evaluation of the thermal performance of the selected typologies, among concretes and panels thickness analyzed, the use of concretes panels with densities of 2400 kg/m³ and thicknesses of 12 cm has been presented better results for the eight Brazilian climate zones.
229

Seleção, caracterização e aplicação de novos biossurfatantes produzidos por bactérias marinhas a partir de substratos de baixo custo / Selection, characterization and application of biosurfactantes produced by marine bacterial using low-cost substrates

Vilela, Willian Fernando Domingues 14 April 2014 (has links)
Os surfatantes, moléculas anfipáticas compostas por uma porção polar e outra apolar, constituem um grupo heterogêneo de compostos de superfície ativa. Sua porção polar pode ser formada por peptídeos, ânions ou cátions, por mono, di ou polissacarídeos, enquanto sua porção apolar pode ser formada por estruturas saturadas, insaturadas ou ácidos graxos hidroxilados, ou ainda peptídeos hidrofóbicos. Essas substâncias podem ser sintéticas, obtidas a partir de síntese química, ou produzidas por micro-organismos, principalmente, bactérias e leveduras, passando a ser denominadas biossurfatantes (BS). O BS representa uma alternativa aos tensoativos sintéticos utilizados em diversos seguimentos da indústria devido a sua baixa toxicidade e alta biodegradabilidade, além de aplicabilidade na descontaminação ambiental. Bactérias isoladas em diversos biomas têm sido muito exploradas para produção de BS, enquanto ecossistemas marinhos ainda são pouco explorados, apesar do grande potencial existente. Os micro-organismos marinhos quando expostos a condições extremas de pressão, salinidade e temperatura produzem compostos estáveis e, portanto, úteis em aplicações industriais. O presente trabalho objetivou investigar novos BS produzidos por bactérias de origem marinha capazes de produzir tal substância a partir de fontes de carbono de baixo custo (glicerol, óleo de soja, vaselina e sacarose). Foram analisados 59 isolados bacterianos marinhos, as bactérias selecionadas foram identificadas e a produção do BS foi estudada em escala laboratorial. Após a extração do BS, suas propriedades físico-química como tensão superficial (TS), tensão interfacial (IT) e concentração micelar crítica (CMC) foram determinadas; além disso, foi realizada a caracterização estrutural preliminar e o seu potencial de aplicação para biorremediação de petróleo e como agente emulsificador. Os resultados identificaram a produção de BS por três bactérias marinhas: Arthrobacter defluvii, Brevibacterium luteolum e Gordonia sp. A partir das análises químicas foi possível identificar dois BS lipopepítidicos (A. Defluvii e B. luteolum) e um BS com grupos glicosídicos (Gordonia sp.). O BS produzido por A. defluvii apresentou tensão superficial TS = 34,5 mN m-1; TI = 15 mN m-1; e CMC = 129 mg L-1 crescendo em óleo de soja, B. luteolum TS = 27 mN m-1; TI = 0,84 mN m-1; e CMC = 40 mg L-1 crescendo em vaselina e Gordonia sp. TS = 33 mN m-1; TI = 1,4 mN m-1; e CMC = 85 mg L-1 crescendo em óleo de soja. Os BS estudados apresentaram capacidade de remoção de petróleo de areia contaminada, assim como atividade emulsificante frente a diferentes substâncias ( óleo de soja, vaselina, decano, querosene, hexadecano e gordura vegetal). Os testes de estabilidade realizados para BS produzido por B. luteolum indicaram que: o BS é estável quando submetido a temperaturas até 60oC por 24 h e até 121oC por 20 min; a maior atividade tensoativa para o BS é encontrada em solução com pH entre 6 e 8; e a força iônica não afeta a atividade tensoativa até concentrações salinas abaixo de 16%. Portanto, os três micro-organismos marinhos selecionados foram capazes de produzir compostos com relevante atividade tensoativa utilizando substratos de baixo custo. / The surfactants, amphipathic molecules containing both polar and nonpolar portions, are a heterogeneous group of surface-active compounds. Its polar portion may be composed by peptides, anions or cations, mono, di, or polysaccharides, while its polar portion may contain saturated, unsaturated or hydroxylated fatty acids or hydrophobic peptides. These molecules may be synthetic, derived from chemical synthesis, or produced by microorganisms, mainly bacteria and yeast, and also known as biosurfactants (BS). The BS represent an alternative to synthetic surfactants used in various segments of industry due to their low toxicity and high biodegradability. The major classes of BS include glycolipids, lipopeptides, lipoproteins, phospholipids, fatty acids and polymeric surfactants. Bacteria isolated from different biomes have been heavily exploited for BS production, while marine ecosystems are still poorly explored, despite its great potential. The marine microorganisms when exposed to extremes of pressure, temperature and salinity, produce stable compounds and, therefore, useful in industrial applications. The aim of this study was to investigate new BS produced by marine bacteria capable of producing such molecules growing in low-cost carbon sources (mineral oil, sucrose, soybean oil and glycerol). The selected bacterial isolates were identified and the biosurfactant production was studied in laboratory scale. After extraction of BS their physicochemical properties as surface tension (ST), interfacial tension (IT) and critical micelle concentration (CMC) were determined; preliminary structural characterization evaluated by FTIR and TLC and their potential application in bioremediation of crude oil and as emulsifier was also investigated. The results identified the BS production by three marine bacteria Arthrobacter defluvii, Brevibacterium luteolum and Gordonia sp. Based on the chemical analysis it was possible to identify two lipopeptides BS (A. defluvii and B. luteolum) and a BS with glycosides groups (Gordonia sp.). The BS produced by A. defluvii growing in soybean oil showed ST = 34,5 mNm-1; IT = 15 mNm-1 and CMC = 129 mgL-1; B. luteolum growing in mineral oil showed a ST = 27 mNm-1, IT = 0,84 mNm-1 and CMC = 40 mgL-1 and Gordonia sp. growing in soybean oil showed ST = 33 mNm-1, IT = 1,4 mNm-1 and CMC = 85 mgL-1. The BS obtained exhibited capacity to remove crude oil from contaminated sand as well as emulsifying activity against different hydrophobic substances (soybean oil, mineral oil, decane, kerosene, animal fat and hexadecane). Stability tests carried out to BS produced by B. luteolum indicated that: the BS is stable when submitted to temperatures down to 60° C for 24 h to 121° C for 20 min; the higher activity to the BS is found in solution with pH between 6 and 8; and the ionic strength does not affect the surfactant activity until salt concentrations under 16%. Therefore, the three selected marine micro-organisms were able to produce compounds with significant surfactant activity using low cost substrates.
230

Plataformas de baixo custo à base de papel para testes imunodiagnósticos e enzimáticos / Low-cost paper-based platforms for immunodiagnostic and enzymatic testing

Nascimento, Thiago Mazzú do 09 December 2016 (has links)
Os imunoensaios e os ensaios bioquímicos são amplamente utilizados em clinica médica. Os dispositivos fabricados em papel devido ao seu baixo custo, portabilidade, todas as etapas serem realizadas em temperatura ambiente, e possibilidade da produção local dos dispositivos, tornam-se ideais para serem aplicados em regiões carentes. Assim, desenvolvemos um ensaio imunocromatográfico que permitiu a detecção de IgG de coelho em um dispositivo com uma única camada de papel impressa por cera, mostrando que esse protótipo tem potencial de ser aplicado em diferentes ensaios imunológicos. Pela primeira vez foi utilizado um teste enzimático colorimétrico (sarcosina oxidase, peroxidase e o indicador redox (ABTS) em plataforma de papel, impressa por cera, para detecção de sarcosina, o qual detectou um potencial marcador de tumor de câncer de próstata, a sarcosina, com limite de detecção (LD) = 0,21 mmol L-1 e limite de quantificação (LQ) = 0,61 mmol L-1, constatando que a intensidade da cor formada foi proporcional a concentração de sarcosina presente na amostra. Os imunoensaios em papel se mostraram extremamente versáteis, capazes de detectar diferentes analitos. O primeiro dispositivo foi capaz de detectar toxoplasmose (IgG contra T. gondii presente nas amostras). A avaliação da performance do teste nos forneceu um cut-off =21,73 U.A, sensibilidade = 0,96, especificidade = 0,87, AUC = 0,97, além de uma criação de uma zona cinza utilizando uma tolerância em porcentagem sobre a o cut-off de 15%. Desenvolvemos também uma macro no excel qye calcula a acurácia, m-Acuraccy, a qual nos forneceu um valor de 0,88 U.A. O segundo dispositivo permitiu a detecção do marcador tumoral CEA, através de um ensaio do tipo sanduíche, com um cut-off =68,28 U.A, sensibilidade = 0,86, especificidade = 1, AUC = 0,97. A tolerância em porcentagem sobre a o cut-off para a criação da zona cinza foi de 12%, e a m-Acuraccy calculou uma acurácia de 0,90 U.A. Pela primeira vez, foi aplicada essa completa avaliação estatística em testes em papel. Mais do que isso, trazemos com a m-Acuraccy uma nova forma de calcular a acurácia, com grande inovação na clínica médica. Portanto, torna-se evidente o grande potencial que os dispositivos fabricados em papel possuem para ser aplicados como ferramentas diagnósticas. / Immunoassays and bioassays are broadly used in clinical medicine. Paper-based devices are ideal to be used in remote regions due to their low-cost, portability and the possibility of in loco manufacture. Paper-based immunoassays are extremely versatile, capable of detecting distinct analytes: initially we have developed an immunochromatographic assay to detect rabbit IgG in a paper-based device fabricated using wax printing technology, and we have shown that this prototype has potential to be applied in distinct immunoassays. The second developed paper-based device was an enzymatic colorimetric assay for the detection of a potential prostate cancer biomarker - sarcosine (sarcosine oxidase, peroxidase and redox indicator (ABTS)), obtaining good figures or merit (LOD = 0.21 mmol L-1; LOQ = 0.61 mmol L-1, r² = 0.890). The third developed paper-based device was capable of detecting toxoplasmosis (IgG against Toxoplasma gondii in human serum samples). The performance evaluation showed a cut-off = 21.73 A.U., sensitivity = 0.96, specificity = 0.87, AUC = 0.97, besides defining the gray zone as the zone comprehended in-between 15% over the cut-off value. We also have developed a Microsoft Excel® macro to calculate diagnostic test\'s accuracy - m-Accuracy - that is a new way to calculate accuracy with great innovation for clinical medicine, which resulted in an accuracy of 0.88. for toxoplasmosis assay. The fourth developed paper-based device was used to detect CEA tumor biomarker using a sandwich ELISA assay, with a cut-off = 68.28 A.U., sensitivity = 0.86, specificity = 1.0, AUC = 0.97. The defined gray zone to this test was the zone comprehended in-between 12% over the cut-off value, with an accuracy of 0.90. To the best of our knowledge, this is the first complete statistical evaluation of paper-based diagnostic devices, which showed the great potential of this technology to be used as a new point-of care diagnostic tool.

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