År 2020 listade Världshälsoorganisationen (WHO) cancer som den globalt ledande dödsorsaken med över 10 miljoner dödsfall årligen. Av dessa 10 miljoner fall förekommer nästan 70% i låg- till medelinkomstländer - en siffra som på grund av den låga prioriteringen av cancerbehandling- och diagnostik förväntas öka till 85% redan år 2030. Att utveckla enkla, specifika och prisvärda verktyg för diagnostik kommer därför att bli avgörande för förebyggandet av cancer på en global nivå. För att komma ett steg närmare denna utveckling optimerades och testades i denna studie ett mikrofluidiskt system, utvecklat genom layer-bylayer- metoden, baserat på cellulosa nanofibriller med förmågan att isolera och fånga cirkulerande tumörceller. För att uppnå en termodynamisk jämvikt optimerades systemets hydrodynamiska parametrar optimerades för att uppnå en homogen fördelning med hög densitet av det cellulosa-baserade systemet i det mikrofluidiska chippet. Då jämvikt är grundläggande för att maximera det efterföljande beläggningen av antikroppar, och därmed hur effektivt celler isoleras, modifierades parametrar såsom koncentration, flödeshastighet, inkubationstid med fler tills att önskad effekt uppnåtts. Således koncepttestades systemet genom att fånga celler spetsade i blod och därmed demonstrera att systemet kan användas i syfte att isolera cancerceller från blodprov. Detta öppnar upp för utveckling av liknande diagnostiska verktyg som kan användas för att isolera lågfrekventa celler direkt från blod. / In 2020, the World Health Organization (WHO) listed cancer as the leading cause of death worldwide, reaching a staggering number of 10 million cancer-related deaths annually. Of these 10 million deaths, nearly 70% occurred in low- and middle-income countries; a number that is expected to increase to 85% by 2030 due to the lack of resources as well as low priority of the development of cancer treatment and diagnosis. Hence, the development of a sophisticated, specific and affordable diagnostic tool will be crucial for global cancer prevention and control. In this study, a cellulose nanofibril-based Layer-by-Layer system for immuno-capture of tumour cells in a microfluidic device was optimized and tested for the development of a simple and cost-effective diagnostic tool for use in resource-limited areas. In the pursuit of a thermodynamic equilibrium, the hydrodynamic parameters of the system were optimized to achieve a homogeneous distribution with a high surface density of the cellulose-based system across the microfluidic channels. Since an equilibrated system is essential to maximize the antibody coating, and thereby cell capture efficiency, parameters including but not limited to concentration, flow rate and incubation time were altered until a desired effect had been achieved. Thus, as proof-of-concept, the system was tested by capturing cancer cells spiked into whole blood, thereby demonstrating that the system can be utilized for the purpose of isolating cancer cells from blood samples. This paves the way for the development of similar clinical diagnostic tools for the isolation of rare cells directly from whole blood.

Bakgrund: Natrium (Na+) är en viktig elektrolyt i kroppen, och analyseras bland annat för att kunna bedöma patientens tillstånd och för att avgöra om akut behandling är nödvändigt. Analysen av Na+ på intensivvårdsavdelningen (IVA) i Örebro sker med hjälp av GEM Premier 5000, vilket är ett patientnära instrument som använder direkt metod för analys av helblod. Vid patientprovsjämförelse skickas provet vidare till centrallaboratoriet där plasman analyseras genom indirekt metod på Advia Chemistry XPT. Avvikelse mellan metoderna får inte överstiga 3%, annars måste orsaken utredas.  Syfte: Syftet med arbetet är att undersöka om det finns en systematisk skillnad på natrium-resultat mellan patientnära instrument, Gem Premier 5000 och centrallaboratoriets instrument, Advia Chemistry XPT hos olika patientgrupper. Metod: Mätning utfördes på blodprover tagna i litium-heparin rör på 60 deltagare, varav 30 var friska blodgivare (grupp 1) och resterande 30 bestod av inneliggande patienter (IVA) samt njurdialys-patienter, (grupp 2). Proverna analyserades för natrium i helblod på GEM Premier 5000 och strax därefter analyserades natrium, albumin, totalt protein, C-reaktivt protein (CRP), glukos och triglycerider i plasma på Advia Chemistry XPT. Resultat: Advia Chemistry XPT gav en högre medelkoncentration av Na+ (139 mmol/L) än GEM Premier 5000 (138 mmol/L) sett till samtliga deltagare. Procentuella skillnaden för natrium mellan metoderna översteg 3% för 3 deltagare i grupp 1 respektive hos hälften av deltagarna i grupp 2.   Slutsats: Na+ resultat på Advia Chemistry XPT var högre än på GEM Premier 5000 för alla deltagare. Skillnaden var större hos patienter med hög grad av sjuklighet. Detta antyder att nuvarande acceptabla avvikelse på 3% bör höjas till 5%, för att antal avvikande värden ska reduceras till nästan samma för båda grupper. Detta måste övervägas och implementeras i verksamheten. / Background: Sodium (Na +) is an important electrolyte in the body, and is analyzed, among other things, to be able to assess the patient's condition in the intensive care unit (IVA) and to determine if emergency treatment is necessary. The analysis of Na + on IVA is done with the help of GEM Premier 5000, which is a patient-centered instrument and uses a direct method for analysis of whole blood. For patient sample comparison, the sample is sent to the central laboratory where the plasma is analyzed by indirect method on Advia Chemistry XPT. Deviation between the methods must not exceed 3%, otherwise the cause must be investigated. Aim: The aim of the study is to investigate whether there is a systematic difference in Sodium results between patient-related instruments, Gem Premier 5000 and the central laboratory's instrument, Advia Chemistry XPT in different patient groups. Method: Measurement was performed on blood samples taken in Lithium Heparin tubes of 60 participants, of which 30 were healthy blood donors (group 1) and the remaining 30 consisted of inpatients (IVA) and kidney dialysis patients, (group 2). The samples were analyzed for sodium on GEM Premier 5000 and shortly thereafter for sodium, albumin, total protein, C-reactive protein (CRP), glucose and triglycerides on Advia Chemistry XPT. Results: Advia Chemistry XPT gave a higher concentration of Na + (139 mmol / L) than GEM Premier 5000 (138 mmol / L) for all participants. The percentage difference of Na between the methods differed for 3 participants in group 1 while it differed for half of the participants in group 2. Conclusion: Na + results on Advia Chemistry XPT were higher than on GEM Premier 5000 for all participants. The difference was greater in patients with a high degree of morbidity. This suggests that the current acceptable deviation of 3% should be increased to 5%, in order to reduce the number of deviating values ​​to almost the same for both groups. This must be taken into account and implemented in the business.

Background: In reconstructive surgery, loss of a microvascular free flap due to perfusion disorders, especially thrombosis, is a serious complication. In recent years, viscoelastic testing (VET) has become increasingly important in point-of-care (POC) anticoagulation monitoring. This paper describes a protocol for enhanced anticoagulation monitoring during maxillofacial flap surgery. Objective: The aim of the study will be to evaluate, in a controlled setting, the predictive value of POC devices for the type of flap perfusion disorders due to thrombosis or bleeding. VET, Platelet monitoring (PM) and standard laboratory tests (SLT) are comparatively examined. Methods/Design: This study is an investigator-initiated prospective trial in 100 patients undergoing maxillofacial surgery. Patients who undergo reconstructive surgery using microvascular-free flaps will be consecutively enrolled in the study. All patients provide blood samples for VET, PM and SLT at defined time points. The primary outcome is defined as free flap loss during the hospital stay. Statistical analyses will be performed using t-tests, including the Bonferroni adjustment for multiple comparisons. Discussion: This study will help clarify whether VET can improve individualized patient care in reconstruction surgery. A better understanding of coagulation in relation to flap perfusion disorders may allow real-time adaption of antithrombotic strategies and potentially prevent flap complications.

Thesis (MBA)--Stellenbosch University, 2014. / There is a growing trend towards the use of point of care testing in resource poor settings, in particular in the diagnosis and treatment of infectious diseases such as Human Immunodeficiency Virus (HIV), Tuberculosis (TB) and Malaria. The Alere PIMA CD4 counter is widely used as a point of care device in the staging and management of HIV. While the instrument has been extensively validated and shown to be comparable to central laboratory testing, little is known about the error rates of these devices, as well as the factors that contribute to error rates. This research was a retrospective analysis of error rates from 61 PIMA point of care devices deployed in nine African countries belonging to Medisciens Sans Frontiers. The data was collected between January 2011 and June 2013. The objectives of the study were to determine the overall error rate and, where possible, determine the root cause. Thereafter the study aimed to determine the variables that contribute to the root causes and make recommendations to reduce the error rate. The overall error was determined to be 13.2 percent. The errors were further divided into four root causes and error rates assigned to each root cause based on the error codes generated by the instrument. These error rates were found to be operator error (48.4%), instrument error (2.0%), reagent/cartridge error (1%) and sample error (4.3%). It was found that a high percentage of the errors were ambiguous (44.3%), meaning that they had more than one possible root cause. A systems-based knowledge management approach was used to create a qualitative politicised influence diagram, which described the variables that affect each of the root causes. The influence diagram was subjected to loop analysis where individual loops were described in terms of the knowledge type (tacit or explicit), the knowing type (know-how, know-who, know-what and know-why), and the actors involved with each variable. Where possible, the variable was described as contributing to pre-analytical, analytical or post-analytical error. Recommendations to reduce the error rates for each of the variables were then made based on the findings.

UA Open Access Publishing Fund / Molecular diagnostics offers quick access to information but fails to operate at a speed required for clinical decision-making. Our novel methodology, droplet-on-thermocouple silhouette real-time polymerase chain reaction (DOTS qPCR), uses interfacial effects for droplet actuation, inhibition relief, and amplification sensing. DOTS qPCR has sample-to-answer times as short as 3 min 30 s. In infective endocarditis diagnosis, DOTS qPCR demonstrates reproducibility, differentiation of antibiotic susceptibility, subpicogram limit of detection, and thermocycling speeds of up to 28 s/cycle in the presence of tissue contaminants. Langmuir and Gibbs adsorption isotherms are used to describe the decreasing interfacial tension upon amplification. Moreover, a log-linear relationship with low threshold cycles is presented for real-time quantification by imaging the droplet-on-thermocouple silhouette with a smartphone. DOTS qPCR resolves several limitations of commercially available real-time PCR systems, which rely on fluorescence detection, have substantially higher threshold cycles, and require expensive optical components and extensive sample preparation. Due to the advantages of low threshold cycle detection, we anticipate extending this technology to biological research applications such as single cell, single nucleus, and single DNA molecule analyses. Our work is the first demonstrated use of interfacial effects for sensing reaction progress, and it will enable point-of-care molecular diagnosis of infections.

In this dissertation I present results on our efforts to increase the sensitivity and selectivity of silicon nanowire ion-sensitive field-effect transistors for the detection of biomarkers, as well as a novel method for wireless power transfer based on metamaterial rectennas for their potential use as implantable sensors. The sensing scheme is based on changes in the conductance of the semiconducting nanowires upon binding of charged entities to the surface, which induces a field-effect. Monitoring the differential conductance thus provides information of the selective binding of biological molecules of interest to previously covalently linked counterparts on the nanowire surface. In order to improve on the performance of the nanowire sensing, we devised and fabricated a nanowire Wheatstone bridge, which allows canceling out of signal drift due to thermal fluctuations and dynamics of fluid flow. We showed that balancing the bridge significantly improves the signal-to-noise ratio. Further, we demonstrated the sensing of novel melanoma biomarker TROY at clinically relevant concentrations and distinguished it from nonspecific binding by comparing the reaction kinetics. For increased sensitivity, an amplification method was employed using an enzyme which catalyzes a signal-generating reaction by changing the redox potential of a redox pair. In addition, we investigated the electric double layer, which forms around charges in an electrolytic solution. It causes electrostatic screening of the proteins of interest, which puts a fundamental limitation on the biomarker detection in solutions with high salt concentrations, such as blood. We solved the coupled Nernst-Planck and Poisson equations for the electrolyte under influence of an oscillating electric field and discovered oscillations of the counterion concentration at a characteristic frequency. In addition to exploring different methods for improved sensing capabilities, we studied an innovative method to supply power to implantable biosensors wirelessly, eliminating the need for batteries. A metamaterial split ring resonator is integrated with a rectifying circuit for efficient conversion of microwave radiation to direct electrical power. We studied the near-field behavior of this rectenna with respect to distance, polarization, power, and frequency. Using a 100 mW microwave power source, we demonstrated operating a simple silicon nanowire pH sensor with light indicator.

O propósito desta investigação foi avaliar o desempenho funcional e a qualidade técnica de um Software-protótipo desenvolvido para a sistematização da assistência de enfermagem. Foi elaborada uma versão deste ambiente computacional específica para aplicação em dispositivo de mão móvel com interface de rede sem fio integrada possibilitando aos enfermeiros acessar e documentar dados acerca de sinais vitais, balanço hidroeletrolítrico, evolução e prescrição de enfermagem a beira do leito com transmissão de dados em tempo real. Este estudo está alicerçado no Modelo do Processo de Avaliação segundo a ISO/IEC 9126, Parte 1: Modelo de qualidade, que versa sobre qualidade externa e interna de software e a especifica em seis características denominadas: funcionalidade, confiabilidade, usabilidade, eficiência, manutenibilidade e portabilidade, as quais são subdivididas em subcaracterísticas. Foi utilizado subsídio da NBR ISO/IEC 14598 que apresenta uma visão geral do processo de avaliação de software, suas orientações e requisitos. Este estudo descritivo/exploratório foi realizado em uma instituição de ensino superior de enfermagem e duas instituições hospitalares de ensino localizadas no interior do estado de São Paulo. Os avaliadores totalizaram um número de vinte e sete e foram constituídos por oito especialistas em informática; oito enfermeiros docentes e 11 enfermeiros, sendo sete do Hospital A e quatro do Hospital B. Considerando-se a característica de modularidade e adotando o referencial proposto por Pressman (2006), realizaram-se duas etapas de avaliação: teste de unidade modular e de validação. Inicialmente, a verificação concentrou-se em cada uma das doze unidades modulares, em seguida foram avaliados na forma integrada para se proceder ao teste de validação. O desenvolvimento destas duas etapas contou com a participação individual de cada um dos especialistas e ocorreu na presença da pesquisadora. Foi elaborado um instrumento de avaliação (Anexo I) a fim de documentar os dados coletados no teste de unidade modular e com base nas características e subcaracterísticas de qualidade foram desenvolvidos instrumentos específicos para aplicação do teste de validação junto aos especialistas em informática (Anexo II a) e enfermeiros docentes e enfermeiros (Anexo II b). Os resultados demonstraram que a incorporação da tecnologia da computação móvel advinda de rede sem fio às atividades assistenciais de enfermagem proporcionou um ambiente com mobilidade para as ações e facilitou a comunicação e a documentação da assistência prestada. A avaliação dos atributos de qualidade do Software-protótipo em questão foi mensurada pelos especialistas em informática, enfermeiros docentes e enfermeiros destacando-se duas características: usabilidade e eficiência. A usabilidade foi avaliada com 100% de respostas positivas pelos docentes e enfermeiros e com 80,4% de aprovação pelos especialistas em informática evidenciando que o Software-protótipo para a sistematização da assistência de enfermagem (SAE) apresenta facilidade para inserir e obter informações e apresenta-se como um sistema dinâmico para documentar a assistência prestada. A eficiência foi aprovada com 92,3% e 87,5% de respostas positivas pelos enfermeiros docentes e especialistas em informática, respectivamente, demonstrando que uma das vantagens desta ferramenta é armazenar, processar e disponibilizar informações sobre a SAE de forma mais eficiente que a realizada manualmente. / The purpose of this investigation was to evaluate the functional performance and the technical quality of a software-prototype developed for the systematization of the nursing care. A version of this specific computational environment has been developed to be used in hand-mobile devices with integrated wireless network interface allowing the nurses to access and document data related to vital signals, hydroelectrolytic balance, evolution and nursing prescription at the point-of-care with transmission of data in real time. This study is based on Evaluation Process Model, according to ISO/IEC 9126, Part 1: Model of Quality which is versed in external and internal software quality and specifies it in six characteristics denominated: functionality, reliability, usability, efficiency, maintainability, and portability, which are subdivided in sub-characteristics. Subsidy of NBR ISO/IEC 14598 has been used, which presents a general overview of the software evaluation process, its orientations and requirements. This descriptive/exploratory study has been accomplished in a Nursing College and in two school hospital institutions in the interior of the state of Sao Paulo. It has been totaled 27 appraisers, and constituted by eight specialists on computer science; eight faculty members nurses; and 11 registered nurses - seven from Hospital A, and four from Hospital B. Considering the characteristic of modularity, and adopting the reference proposed by Pressman (2006), two stages of evaluation have been accomplished: modular unity test, and validation. Initially, the verification focused on each one of the 12 modular unities, and then they have been evaluated integrally in order to proceed the validation test. Each one of the specialists participated in the development of these two stages, which occurred in the presence of the researcher. An instrument of evaluation has been elaborated (Appendix I) in order to document the data collected in the modular unity test. Based on the characteristics and sub-characteristics of quality, specific instruments for application of the validation test have been developed along with the computer science specialists (Appendix II a), and the faculty members nurses and registered nurses (Appendix II b). The results demonstrated that the incorporation of the mobile computer technology originated from wireless network to the nursing care activities provided an environment with mobility for actions and became communication and documentation of the assistance easier. The evaluation of the quality attributes of the software-prototype was measured by the computer science specialists, faculty members nurses and registered nurses, highlighting two characteristics: usability and efficiency. The usability was evaluated, resulting 100% of positive approval among faculty members nurses, and 80.4% among computer science specialists, demonstrating that the software-prototype for the systematization of nursing care makes the action of inserting and obtaining information easy, and it is presented as a dynamic system to document the provided care. The efficiency was approved with 92.3% and 87.5% of positive answers by the faculty members nurses and computer science specialists, respectively, demonstrating that one of the advantages of this tool is to store, process, and make available information about the nursing process, more efficiently than the one made manually.

No description available.

<p>Objective: The aim of this study was to evaluate a new underfill-function in a POCT-instrument from HemoCue AB (Ängelholm, Sweden). The instrument is in use today among diabetes patients for self-monitoring blood glucose (SMBG). The new function is supposed to guarantee that measuring only will be performed on a sufficient sample volume to assure that the correct glucose value is received.</p><p>Methods and results: Blood samples (whole blood) from 12 patients were analysed with the instrument. Measuring were performed using different volumes in the cuvette. Full cuvette, 3µL, 2µL, 1µL and a measuring on an empty cuvette. The instrument performed measurements on all volumes added to the cuvette except for the empty cuvette. The less sample volume that was used the lower glucose values were reported by the instrument.</p><p>Conclusions: The new under fill-function did not work satisfactory. If such function would be more reliable it would be beneficial for the patient controlling hers/his bloodglucose provided that the testing procedure is being correctly done. This is very important because the results are often used to treat the patient.</p>

This thesis presents technological advancements in microfluidics. The overall goals of the work are to develop new miniaturized tests for point-of-care diagnostics and robust super-lubricating surfaces for friction reduction. To achieve these goals, novel materials, surfaces and manufacturing methods in microfluidics have been developed. Point-of-care diagnostic tests are portable miniaturized instruments that downscale and automate medical tests previously performed in the central laboratories of hospitals. The instruments are used in the doctor’s office, in the emergency room or at home as self-tests. By bringing the analysis closer to the patient, the likelihood of an accurate diagnosis, or a quick therapy adjustment is increased. Already today, there are point-of-care tests available on the market, for example blood glucose tests, rapid streptococcus tests and pregnancy tests. However, for more advanced diagnostic tests, such as DNA-tests or antibody analysis, integration of microfluidic functions for mass transport and sample preparation is required. The problem is that the polymer materials used in academic development are not always suited for prototyping microfluidic components for sensitive biosensors. Despite the enormous work that has gone into the field, very few technical solutions have been implemented commercially. The first part of the work deals with the development of prototype point of-care tests. The research has focused on two major areas: developing new manufacturing methods to leverage the performance of existing materials and developing a novel polymer material platform, adapted for the extreme demands on surfaces and materials in miniaturized laboratories. The novel manufacturing methods allow complex 3D channel networks and the integration of materials with different surface properties. The novel material platform is based on a novel off-stoichiometry formulation of thiol-enes (OSTE) and has very attractive material and manufacturing properties from a lab-on-chip perspective, such as, chemically stable surfaces, low absorption of small molecules, facile and inexpensive manufacturing process and a biocompatible bonding method. As the OSTE-platform can mirror many of the properties of commercially used polymers, while at the same time having an inexpensive and facile manufacturing method, it has potential to bridge the gap between research and commercial production. Friction in liquid flows is a critical limiting factor in microfluidics, where friction is the dominant force, but also in marine applications where frictional losses are responsible for a large part of the total energy consumption of sea vessels. Microstructured surfaces can drastically reduce the frictional losses by trapping a layer of air bubbles on the surface that can act as an air bearing for the liquid flow. The problem is that these trapped air bubbles collapse at the liquid pressures encountered in practical applications. The last part of the thesis is devoted to the development of novel low fluidfriction surfaces with increased robustness but also with active control of the surface friction. The results show that the novel surfaces can resist up to three times higher liquid pressure than previous designs, while keeping the same friction reducing capacity. The novel designs represent the first step towards practical implementation of micro-structured surfaces for friction reduction. / <p>QC 20110907</p>