Non-invasive methods to evaluate skeletal muscle oxidative capacity have beenemerging as a viable substitute for invasive methods in recent years. One ofthose methods utilises near-infrared spectroscopy (NIRS) to calculate V O2mrecovery off-kinetics following an exercise. The data analysis of the measuredsignals from the NIRS is still done manually in a time-consuming and dauntingprocess. The present thesis aimed to develop software, associated with theNIRS method, capable of analysing the recovery from a repeated arterialocclusion protocol following an exercise to assess muscle oxidative capacity.Additionally, to analyse the recovery from ischemic preconditioning as a singletest to assess muscle oxidative capacity. A method that has never been utilisedbefore.11 active, healthy subjects were analysed to calculate their recovery rate.Subjects underwent ischemic preconditioning before exercising for 6 minutesat 80% of gas exchange threshold. A repeated arterial occlusion protocol wascarried out after the exercise. A software was developed in R that utilised linearregression as well as exponential fitting to calculate the recovery rate of eachsubject during both the ischemic preconditioning and the occlusion protocol.The calculated results were compared to predetermined recovery rate results ofeach subject. The calculated results of the repeated arterial occlusion protocolgave similar results to the predetermined ones and even more data on eachsubject’s recovery from an exercise. The calculated results of the ischemicpreconditioning were promising and implied that ischemic preconditioning asa single test can be utilised as a method to assess muscle oxidative capacity.However, further research is required to confirm it. / Icke-invasiva metoder för att utvärdera skelettmuskulaturens oxidativa förmågahar på senare år blivit en användbar ersättning för invasiva metoder. Nearinfrared spectroscopy (NIRS) är en utav dessa metoder och har använts föratt beräkna V O2m återhämtning off-kinetics efter träning. Dataanalysen av deuppmätta signalerna från NIRS görs fortfarande manuellt i en tidskrävandeoch felbenägen process. Syftet med den här uppsatsen var att utveckla enprogramvara som kopplad till NIRS metoden, kan analysera återhämtningenfrån ett protokoll med upprepade arteriella ocklusioner efter träning för attutvärdera skelettmuskulaturens oxidativa förmåga. Dessutom att analyseraåterhämtningen från ischemic preconditioning som ett enda test för att utvärderaskelettmuskulaturens oxidativa förmåga. En metod som aldrig tidigare använts.11 aktiva, friska försökspersoner analyserades för att beräkna deras återhämtningshastighet.Försökspersonerna genomgick ischemic preconditioning innan de tränadei 6 minuter med 80% av gasutbyteströskeln. Ett protokoll med upprepadearteriella ocklusioner genomfördes efter träningen. En programvara utveckladesi R som använde sig av linjär regression och monoexponentiell funktionsanpassningför att beräkna återhämtningshastigheten för varje försöksperson under bådeichemic preconditioning och ocklusionprotokollet. De beräknade resultatenjämfördes med förutbestämda resultat av återhämtningshastigheten för varjeförsöksperson. De beräknade resultaten av ocklusionprotokollet gav liknanderesultat som de förutbestämda och gav ännu fler uppgifter om varje försökspersonåterhämtning efter träning. De beräknade resultaten av ischemic preconditioningvar lovande och indikerade att ischemic preconditioning som ett enda testkan användas som en metod för att utvärdera skelettmuskulaturens oxidativaförmåga. Det krävs dock ytterligare forskning för att bekräfta detta.

Background: Amyloid transthyretin (ATTR) cardiomyopathy is caused by the deposition of misfolded proteins, known as amyloid fibrils, in the myocardium. Quantitative Single Photon Emission Computed Tomography (QSPECT) utilizing 99mTc-DPD scintigraphy has the potential to assess ATTR-suspected cardiac amyloidosis (CA). This method could offer improved risk stratification and therapy response monitoring compared to the established Perugini score system. The primary objective of this study is to evaluate the feasibility of employing a quantitative approach and correlating various parameters with LVMI (left ventricular mass index). Method: Initially, planar and volumetric sensitivity measurements were conducted, followed by verification of accuracy measurements. Several torso phantom acquisitions were then performed to evaluate the accuracy and repeatability in terms of recovery coefficient (RC) and repeatability deviation (RD). This served as the foundation for the subsequent in vivo quantification. In this retrospective study, 10 patients underwent 99mTc-DPD scintigraphy, including SPECT/CT of the thorax and echocardiography examinations, as part of a clinical routine for suspected CA. The myocardial SUVmax was determined using a semi-automatic segmentation of the entire heart, excluding the descending and ascending aortas. The bone uptake was also quantified using the SUVmean parameter within the automatically delineated volume of all bones. This enabled the determination of the normalized uptake value nSUVmax, (SUVmax to SUVmean bone). Moreover, an attempt was made to apply an automatic segmentation of the myocardium based on 26% and 36% thresholds, which were developed from the torso phantom acquisitions. This approach allowed for the utilization of the injected dose (ID). Results: The planar calibration factor (CF) exceeded the volumetric cross-calibration factor (CCF) by 3.4%. The anthropomorphic phantom exhibited an underestimation of approximately 50% in the myocardium and around 21% in the kidneys. The average RD in the myocardium and kidneys was 2.3% and 1.6%, respectively. A significant quantitative separation was observed between the ATTR and control groups, comprising 6 and 4 patients, respectively (p<0.01 for SUVmax and nSUVmax, and p<0.02 for SUVmean bone). Correlation analysis revealed a weak positive correlation between SUVmax and LVMI; however, the correlation was not statistically significant (ρ = 0.31, p = 0.39). The ID in the 26% and 36% threshold-based segmented myocardium showed a relatively lower negative correlation with LVMI; although this was observed in the small ATTR cohort and was not statistically significant. The latter outcome resulted from the automatic-delineation method, which was unable to segment grade 0 and 1 patients. Conclusion: This study suggests that both CFs can be used in QSPECT. The phantom measurements indicate good repeatability and a significant quantitative underestimation, primarily due to the partial volume effect (PVE). Size and shape-specific PVE corrections, encompassing various activity concentrations of myocardium-to-blood pool ratios, are essential in QSPECT of the myocardium. Moreover, quantitative SPECT/CT utilizing 99mTc-DPD scintigraphy can effectively distinguish between patients with grade 0/1 and those with grade 2/3. This approach has the potential to enhance diagnostic accuracy and improve risk stratification.

Atopic dermatitis (AD) and other atopic diseases are strongly related to skinbarrier dysfunction, a biomeasure which has limited and unsatisfactory assessmenttechniques. Machine learning (ML) powered electrical impedance spectroscopy(EIS) has been shown to differentiate defective barrier function in mice and adults. Techniques such as principal component analysis (PCA) andsupport vector classifiers (SVC) can be used as ML tools to evaluate EIS measurements. EIS measurements taken on unaffected skin of children aged between 4 monthsand 3 years were collected and analysed using the children’s AD status. Measurements were grouped into one of four groups based on this AD status; No AD (No AD was developed up until 2 years of age), Pre AD (measurements takenbefore the onset of AD), AD remission (measurements taken after the onset ofAD) and AD flare (measurements taken during active AD). A SVC model was trained on the raw EIS measurement data to distinguish measurements from twoof the binarized AD status groups; AD flare and No AD. An additional SVC model was trained on the No AD group, distinguishing measurements based onbinarized age groups: measurements taken at 4 months against measurements taken at 3 years of age. The AD model tested on AD flare against No AD within the test set yielded AUC of 0.92, with a sensitivity and specificity of 89.29% and 88.89% respectively. When testing on all groups of the test set, Pre AD and AD remission groups had group means between the AD flare and No AD groups. No data bias against age was detected in the model. The results of the age model showed that age could be chronologically identified by the age model. The AD model was able to differentiate active AD children from children never experiencing AD symptoms on visually unaffected skin and in turn detecting skin barrier dysfunction. Separate studies would need to be conducted to test the predictive power and external validity of the model. Age is a significant factor to consider when designing ML models using EIS data in children, with proper balance in the training set a data bias within the model can be avoided. EIS is a versatile technique due to its data rich nature. Machine learning powered electrical impedance spectroscopy measurements are able to detect skin barrier dysfunction. Age is a significant factor when measuring EIS on children, but can be managed. / Atopisk dermatit (AD) och andra atopiska sjudomar är starkt kopplade tillhudbarrärdefekter, en hudegenskap där diagnosverktygen är begränsade och otillräckliga. Maskininlärning (ML) i kombination med elektrisk impedansspektroskopi (EIS) har visats att kunna differentiera defekta hudbarrärer i möss och hos vuxna människor. Tekniker såsom principalkomponentanalys (PCA) och stödvektormaskiner (SVM) kan användas som ML verktyg för att utvärdera EIS-mätningar. Statistiska analysverktyg såsom reciever operator characteristics (ROC) tillsammans med arean under kurvan (AUC) och andra precisionsmått kan användas för att utvärdera ML modeller. EIS-mätningar utförda på opåverkad hud hos barn mellan 4 månader och 3 års ålder samlades och analyserades med hjälp av barnens atopiska status. Samtliga mätningarna grupperades i en av totalt fyra grupper baserade på deras atopiska status; Ingen AD (Ingen AD hade utvecklats upp till 2 års ålder), Pre AD (mätningarna togs innan sjukdomsförloppet), AD remission (mätningarna togs efter sjukdomsförloppet) och AD aktiv (mätningarn togs under sjukdomsförloppet). En SVM modell tränades på EIS-rådata för att särskilja mellan två av grupperna binärt; AD aktiv och ingen AD. En ytterliggare SVM modell tränades på endast ingen AD-gruppen för att särskilja mellan mätningarna tagna vid åldrarna 4 månader och 3 år, omgjorta till binära grupper.  AD modellen testades med en jämförelse mellan AD aktiv-gruppen och ingen AD-gruppen med test data och resulterade i en AUC på 0.92, med en respektive sensitivitet och specificitet på 89.29\% samt 88.89\%. Modellen testades även på de ytterliggare grupperna i test datan, Pre AD och AD remission som båda hade gruppmedelvärden som låg mellan AD aktiv-gruppens och ingen AD-gruppens. Inga systematiska fel med avseende på barnens ålder hittades i AD-modellen. Resultaten från ålders-modellen visade på att modellen kunde rangordna mätningarna baserat på ålder. AD-modellen kunde differentiera barn med aktiv AD mot barn som aldrig hade uppvisat atopiska symptom på opåverkad hud, vilket innebär en differentiering av hudbarrärdefekter. Separata studier är nödvändiga för att testa prediktiv prestanda hos modellen samt dess externa validitet. Ålder är en signifikant faktor när ML modeller med EIS-data ska designas, men med tillräcklig balans i träningsdatan kan systematiska fel förhindras. EIS är en versatil teknik med avseense på dess datakomplexitet. EIS tillsammans med maskininlärning kan särskilja defekta hudbarriärer hos barn. Ålder är en signifikant faktor när EIS mäts på barn, men kan hanteras.

Stroke is an enormous global burden, six and a half-million people die fromstroke annually [1]. Effectively monitoring blood hemodynamic parameters suchas blood velocity and volume flow permits to help and cure people. This projectaimed to calibrate a custom-made wearable system for measuring cerebral bloodflow (CBF) using a photoplethysmography (PPG) sensor. The measurementswere validated using Doppler ultrasound as a reference method. Five (N=5)subjects (age = 24±1.41 years) were selected for the project. The PPG and Dopplerultrasound probe were placed above the left and right common carotid arteries(CCA), respectively. Measurements were taken simultaneously for 12 secondseach, with six consecutive measurements per subject and 2 time-synchronizedECG recordings. Subsequently, using an extraction algorithm the velocityenvelope (TAMEAN) was extracted from the Doppler image to obtain the bloodvolume flow (ml/min). After synchronization, the PPG signal output expressedin volts was calibrated to the corresponding volume, and a calibration curve wascreated.The extraction algorithm achieved remarkable results, with almost perfectcorrelation with the Doppler image reference, rT AM EAN =0.951 and rvolume=0.975demonstrating its reliability. Challenges encountered during postprocessingand synchronization highlighted the need for careful refinement in the projectframework. Despite successful signal processing and alignment techniques,calibration results were suboptimal due to synchronization difficulties andmotion artifacts. Limitations included impractical measurement locations andsusceptibility to movement artifacts. The calibration process did not yield theexpected outcomes and the project aim was not achieved. All the linear regressionmodels for each subject failed to accurately predict the volume flow based on themeasured voltages. Future work could focus on refining calibration procedures,improving synchronization methods, and expanding studies to include largercohorts. Although the wearable device was tested, the project’s goal was onlypartially achieved, underscoring the complexity of accurately measuring cerebralblood flow using PPG sensors. / Stroke är en enorm global börda, sex och en halv miljon människor dör av strokeårligen [1]. Effektiv övervakning av hemodynamiska blodparametrar såsomblodflödeshastighet och volymflöde gör det möjligt att hjälpa och bota människor.Detta projekt syftade till att kalibrera ett specialtillverkat bärbart system föratt mäta cerebralt blodflöde (CBF) med hjälp av en fotopletysmografisensor(PPG). Mätningarna validerades med Doppler-ultraljud som referensmetod. Fem(N=5) försökspersoner (ålder = 24±1.41 år) valdes ut för projektet. PPG- ochDoppler-ultraljudssonden placerades över vänster respektive höger gemensamhalsartär (CCA). Mätningar togs samtidigt i 12 sekunder vardera, med sexpå varandra följande mätningar per försöksperson och 2 tids-synkroniseradeEKG-inspelningar. Därefter användes en extraktionsalgoritm för att extraherahastighetskuvertet (TAMEAN) från Doppler-bilden för att få blodvolymflödet(ml/min). Efter synkronisering kalibrerades PPG-signalens utgång uttryckt i volttill motsvarande volym, och en kalibreringskurva skapades.Extraktionsalgoritmen uppnådde anmärkningsvärda resultat, med nästan perfektkorrelation med Doppler-bildreferensen, rT AM EAN =0.951 och rvolume=0.975,vilket visar dess tillförlitlighet. Utmaningar som uppstod under efterbearbetningoch synkronisering betonade behovet av noggrann förfining av projektetsramverk. Trots framgångsrik signalbehandling och justeringstekniker varkalibreringsresultaten suboptimala på grund av synkroniseringssvårigheteroch rörelseartefakter. Begränsningar inkluderade opraktiska mätplatser ochkänslighet för rörelseartefakter. Kalibreringsprocessen gav inte de förväntaderesultaten och projektmålet uppnåddes inte. Alla linjära regressionsmodellerför varje försöksperson misslyckades med att noggrant förutsäga volymflödetbaserat på de uppmätta spänningarna. Framtida arbete kan fokusera på att förfinakalibreringsprocedurer, förbättra synkroniseringsmetoder och utöka studier tillatt omfatta större kohorter. Även om den bärbara enheten testades, uppnåddesprojektets mål endast delvis, vilket understryker komplexiteten i att noggrantmäta cerebralt blodflöde med hjälp av PPG-sensorer.

In the chemistry branch of science is often a chromatograph usedto separate and purify substances in a solution. In achromatograph, different detectors are used to analyse the samplesconstituents. Some detectors destroy the sample during analysis.Because it is undesirable to destroy the entire flow of sample, asmall mass is transferred to a second flow by a flow splitter. Inthis report, four principles to divert a small mass from one flowto another are developed and evaluated. The basic principles todivert the flows is tested and principal mock-ups are designed andmanufactured. A brief survey of the market is conducted and aproblem related to flow spitting is investigated. The problem isthe influence on yield through a chromatograph due to flowretaining. Designing and testing of different retaining systems isalso included in this report. All four initial principles proved to be plausible splittingtechniques. However, only two principles appeared to be feasiblefor direct implementation in devices comparable withchromatographs. One of the less feasible principle is covered byseveral patents. The other is difficult to manufacture in order tomeet the strict requirements associated with e.g. chromatographs.The testing of different retaining systems showed that smallertube inner diameter and how the tube is winded can reduce theretaining system influence on the yield significantly. The splitting techniques in this report are all feasible splittingtechniques, and the report can be used as a solid foundation fordevelopment future laboratory instruments. / Inom kemin förekommer ofta kromatografer för att rena och separera kemiska substanser iett prov. De separerade substanserna kan detekteras och analyseras av olika detektorer, därvissa detektorer förstör provet i analysprocessen. Då det oftast är önskvärt att bevara såmycket som möjligt av ett prov, för vidare studier, avleds därför en liten mängd av deseparerade substanserna till detektorn då en förstörande detektor används. I denna studieutvecklades och undersöktes fyra principer för att avleda mycket små volymer från ett flödetill ett annat. Flödesdelning och sammanförning med de grundläggande flödesdelningsprincipernatestades, principiella modeller konstruerades och tillverkades. Enmarknadsundersökning samt en undersökning av ett flödesdelningsassocierat probleminkluderas också i rapporten. Problemet består i minskning av utbyte på grund avbandbreddning i flödesfördröjningssystem. Bandbreddning studerades således i olika formerav flödesfördröjningssystem. Alla fyra principer visade sig vara möjliga flödesdelningstekniker varav två av sådan karaktäratt de skulle kunna realiseras i ett instrument såsom en kromatograf. Av de två andra omfattasden ena av flertalet patent och den andra skulle vara tillverkningstekniks svår att förverkligamed vedertagna tillverkningstekniker. Tester på olika typer avflödesfördröjningssystemutformningar visade att slangdimension och hur slangen är lindadhar stor inverkan på bandbreddning. Det återstår en hel del konceptuell utveckling då principerna bara behandlats pågrundläggande nivå. Genom de principiella modellerna ges en bild av hur principerna skullekunna förverkligas, men vidare ställningstaganden måste tas till bland annat materialval samtmonitorering och anpassning av flöden. Rapporten ger en god grund för framtidaproduktutveckling.

To increase the survival rate from infectious- and noncommunicable diseases, reliable diagnostic during the preliminary stages of a disease onset is of vital importance. This is not trivial to achieve, a highly sensitive and selective detection system is needed for measuring the low concentrations of biomarkers available. One possible route to achieve this is through biosensing based on plasmonic nanostructures, which during the last decade have demonstrated impressive diagnostic capabilities. These nanoplasmonic surfaces have the ability to significantly enhance fluorescence- and Raman signals through localized hotspots, where a stronger then normal electric field is present. By further utilizing a periodic sub-wavelength nanohole array the extraordinary optical transmission phenomena is supported, which open up new ways for miniaturization. In this study a nanoplasmonic chip (NPC) composed of a nanohole array —with lateral size on the order of hundreds of nanometer— covered in a thin layer of gold is created. The nanohole array is fabricated using soft nanoimprint lithography on two resists, hydroxypropyl cellulose (HPC) and polymethyl methacrylate (PMMA). An in depth analysis of the effect of thickness is done, where the transmittance and Raman scattering (using rhodamine 6G) are measured for varying gold layers from 5 to 21 nm. The thickness was proved to be of great importance for optimizing the Raman enhancement, where a maximum was found at 13 nm. The nanohole array were also in general found beneficial for additionally enhancing the Raman signal. A transmittance minima and maxima were found in the region 200-1000 nm for the NPCs, where the minima redshifted as the thickness increased. The extraordinary transmission phenomena was however not observed at these thin gold layers. Oxygen plasma treatment further proved an effective treatment method to reduce the hydrophobic properties of the NPCs. Care needs be taken when using thin layers of gold with a PMMA base, as the PMMA structure could get severely damaged by the plasma. HPC also proved inadequate for this projects purpose, as water-based fluids easily damaged the surface despite a deposited gold layer on top.

In a time when microorganisms are controlling the world, research in biology is more relevant than ever and this requires some powerful instruments. Optical tweezers use a focused laser beam to manipulate and probe objects on the nano- and microscale. This allows for the exploration of a miniature world at the border between biology, chemistry and physics. New methods for biophysical and physicochemical measurements are continuously being developed and at Umeå University there is a need for a new system that combines several of these methods. This would truly be the new Swiss army knife of biophysical and biomechanical research, extending their reach in the world of optical tweezing. My ambition with this project is to design and construct a robust system that incorporates optical trapping with high-precision force measurements and Raman spectroscopy, as well as introducing the possibility of generating multiple traps by using a spatial light modulator (SLM). The proposed design incorporates four different lasers and a novel combination of signal detection techniques. To allow for precise control of the systems components and laser beams, I designed and constructed motorized opto-mechanical components. These are controlled by an in-house developed software that handles data processing and signal analysis, while also providing a user interface for the system. The components include, motorized beam blockers and optical attenuators, which were developed using commonly available 3D printing techniques and electronic controllers. By designing the system from scratch, I could eliminate the known weaknesses of conventional systems and allow for a modular design where components can be added easily. The system is divided into two parts, a laser breadboard and a main breadboard. The former contains all the equipment needed to generate and control the laser beams, which are then coupled through optical fibers to the latter. This contains the components needed to move the optical trap inside the sample chamber, while performing measurements and providing user feedback. Construction and testing was done for one sub-system at a time, while the lack of time required a postponement for the implementation of Raman and SLM. The system performance was verified through Allan variance stability tests and the results were compared with other optical tweezers setups. The results show that the system follows the thermal limit for averaging times (τ) up to ~1 s when disturbances had been eliminated, which is similar to other systems. However, we could also show a decrease in variance all the way to τ = 2000 s, which is exceptionally good and not found in conventional systems. The force-resolution was determined to be on the order of femtonewtons, which is also exceptionally good. Thus, I conclude that this optical tweezers setup could lie as a solid foundation for future development and research in biological science at Umeå University for years to come.

GE Healthcare Bio-Sciences AB in Umeå produce a variety of chromatography systems. One of the main components in chromatography is the UV module, which measure the light absorption of different wavelengths in the liquid being pumped through a cell. Currently at the Umeå site two types of UV-cells are produced; lab cells and industrial cells. The current test station for the industrial UV-cells is outdated, in disrepair and no longer supported.  GE has developed a test station for the lab cells that evaluates UV and flow properties, the data is stored in GE’s own production database, Prodas. The aim of this work is to design a test station for industrial UV-cells to improve the quality of the cells. The primary goal is a test station that can measure pressure, flow and absorption. The secondary goal is to discover and if possible, implement solutions that will streamline and automate the test station. A prototype of a test station for industrial UV-cells based on that for lab cells has been developed. The solution consists of an adapter that links the light path from the monitor through the UV-cell to the detector. The test station can measure pressure, flow and absorption but can only perform absorption and leakage tests.  Automation and efficiency have been accomplished in the form of scripts used to conduct absorption and leakage tests. The test station requires further development before it can be used in the production line. / GE Healthcare Bio-Sciences AB i Umeå tillverkar ett flertal system, ett av systemen är vätskekromatografen. Vätskekromatografen är en kemisk separationsmetod som använder sig av en UV-monitor, UV-detektor och en UV-cell för att mäta absorptionen av en lösning och framta koncentrationen av det eftersökta ämnet. På anläggningen i Umeå tillverkas två typer av UV-celler; laborationceller och industriceller. För labbcellerna har GE utvecklat en teststation som testar och utvärderar UV och flödesegenskaper samt lagrar data i GE:s egen produktionsdatabas, Prodas. Den befintliga stationen för industriceller är äldre och omodern, en utveckling behövs för att upprätthålla högre kvalité. Syftet med detta projekt är att uppdatera teststationen för industriella UV-celler till samma nivå som stationen för laborationsceller. Det primära målet är att konstruera och designa en teststation för industriella UV-celler som kan mäta tryck, flöde och absorption. Det sekundära målet är att upptäcka och om möjligt verkställa lösningar som kommer effektivisera och automatisera mätningarna. En prototyp av en teststation för industriella UV-celler baserat på den för laborationceller har framtagits, och består av en adapterlösning som används för att sammanlänka ljusbanan från monitorn genom flödescellen till detektorn. Prototypen kan enbart utföra absorption och läckagemätningar. Automatisering och effektivisering har utförts i form av scripts som används för att genomföra absorptions och läckagemätning. Teststationen kräver fortsatt vidareutveckling innan den kan används i produktionslinjen.

The field of organ-on-chip is a relatively new area of research and builds upon the principle of engineering microfluidic systems to mimic the body’s internal environment as precisely as possible. Eventually these models could hopefully simulate whole organ-systems and enable the examination of the cell’s or organ’s reaction to foreign substances like new pharmaceuticals in a better way than current models. Previously this has been done with in vitro models such as petri dishes that only offer static culturing conditions. These are not very realistic environments compared to the human body where the cells are exposed to both variations in pressure and flows among other things. The purpose of this bachelor’s thesis project has been to evaluate and improve the design of an organ-on-chip system developed by the EMBLA-group at Ångströmslaboratoriet, Uppsala university. This has been done by evaluating the manufacturing process to find areas of improvements of the current chip design, as well as conducting a literature study to understand key components of similar organ-on-chip systems and see if it is possible to implement relevant parts to the organ-on-chip of this project. One of these important parts is a so-called bubble trap. A bubble trap is a construction that enables the capturing and elimination of bubbles in the system since the bubbles can harm the chips components, kill the cells, and compromise measurements.  A first prototype of the bubble trap was developed in Polydimethylsioxane (PDMS) and integrated on the EMBLA-group’s chip design. The principle behind the bubble trap was to use the natural buoyancy of the bubbles to trap them. This was done by introducing an upwards going slope before the inlets to the chip. In this manner the bubbles would float up to the top of the slope and accumulate at the roof as the liquid moved on into the chip without bubbles. To make the bubbles leave the chip a low-pressure chamber was added on top of the bubble trap to help the process of the bubble’s diffusion through the roof and out of the chip. The development of an improved chip design turned out to be a time-consuming endeavor and the time left for evaluation the functionality of the chip became too short. One test was performed which showed that the bubbles did accumulate at the top of the slope as expected, but it rapidly became full and thus started to let bubbles through to the microfluidic chip. The bubbles did not diffuse as efficiently as required and the removal of the bubbles became inefficient. To understand and correct the problem areas of this bubble trap design further tests and experiments will have to be conducted. / Organ-på-chip (Organ-on-chip eller OoC) är ett relativt nytt forskningsområde som bygger på att mikrofluidiksystem utvecklas till att efterlikna människokroppen i så stor utsträckning som möjligt. Detta då det är attraktivt att kunna undersöka cellers/organs beteende vid tillförsel av vissa substanser, till exempel nya läkemedel. I tidigare in vitro modeller har det endast observerats och utförts tester på celler odlade i statiska förhållanden vilket inte är likt den omgivning cellerna har i människokroppen där de tex utsätts för olika vätskeflöden och tryckförändringar.    Syftet med detta examensarbete har varit att utvärdera och förbättra designen på ett OoC system utvecklat av EMBLA-gruppen på Ångströmlaboratoriet vid Uppsala universitet. Detta har gjorts genom att studera den nuvarande tillverkningsprocessen för att hitta relevanta förbättringsområden samt att genom en litteraturstudie undersöka viktiga delar som bör ingå i dessa typer av system. En av dessa delar är en bubbelfälla (bubble trap eller BT) vilket innebär att det i chippet bör finnas ett sätt att eliminera/fånga upp bubblor. Detta eftersom bubblorna kan orsaka stor skada på både chipet, cellerna och mätningarna som skall utföras. En första prototyp av en BT design i Polydimetylsiloxan (PDMS) utvecklades och integrerades på EMBLA-gruppens OoC design. Principen bakom BT-designen var att utnyttja bubblornas flytkraft vilket gjordes genom att introducera en uppåtgående backe innan ingångskanalen. Bubblorna kan därmed flyta upp till toppen av lutningen och vätskan kan fortsätta in i mikrochipset utan bubblor. För att bubblorna ska ta sig ut ur chippet integrerades en tryckkammare ovanpå BT-designen för att få bubblorna att diffundera ut genom taket i den uppåtgående kammaren och ut ur chippet. Utvecklingen av den förbättrade chip-designen visade sig var tidskrävande och tiden för att utvärdera designens funktionalitet blev för kort. Ett test gjordes på den nya chip-designen vilket visade att den utvecklade BT som väntat fångade upp bubblor men att den snabbt blev full i och med att bubblorna inte diffunderade ut genom taket i den takt som behövdes. Vidare undersökningar och experiment behövs för att evaluera vad som orsakade detta och rätta till eventuella felkällor i design och experimentuppställning.

Background: Scanners are becoming widespread in Prosthetics and Orthotics, replacing plaster casting in the manufacture of some types of devices. P&O shape capture must be accurate and reliable, so the device is comfortable and reproducible between clinicians/sessions. Objectives: To map knowledge on measuring accuracy and reliability of spatial data produced from 3D scanners. Methods: The study design was a scoping review using the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Studies published in or after 2010 in English with a full-text available that analyse either the accuracy/validity or reliability of human 3D scanning data within a P&O context. Sources were obtained from Pubmed, CINAHL, Scopus, Cochrane Library, Web of Science, and AMed databases on 25th March. Results: The search identified 115 studies of which 9 were included (7 experimental [4 prosthetic, 3 orthotic], 1 systematic review, 1 literature review). 7 analysed both reliability and accuracy/validity and 2 analysed reliability. High heterogeneity amongst studies’ methods, techniques, and equipment. Conclusion: Methods, techniques, and equipment used to measure accuracy/validity and reliability varied greatly though more so in the measurement of accuracy/validity. Within the studies, researchers called for more research on standardisation of measurement methods and techniques.