| 1. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
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| 4. |
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| 5. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 6. |
- Ahmed, A., et al.
(författare)
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Highly efficient composite electrolyte for natural gas fed fuel cell
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:16, s. 6972-6979
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Tidskriftsartikel (refereegranskat)abstract
- Solid oxide fuel cells (SOFCs) have the ability to operate with different variants of hydro carbon fuel such as biogas, natural gas, methane, ethane, syngas, methanol, ethanol, hydrogen and any other hydrogen rich gas. Utilization of these fuels in SOFC, especially the natural gas, would significantly reduce operating cost and would enhance the viability for commercialization of FC technology. In this paper, the performance of two indigenously manufactured nanocomposite electrolytes; barium and samarium doped ceria (BSDC-carbonate); and lanthanum and samarium doped ceria (co-precipitation method LSDC-carbonate) using natural gas as fuel is discussed. The nanocomposite electrolytes were synthesized using co-precipitation and wet chemical methods (here after referred to as nano electrolytes). The structure and morphology of the nano electrolytes were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fuel cell performance (OCV) was tested at temperature (300-600 °C). The ionic conductivity of the nano electrolytes were measured by two probe DC method. The detailed composition analysis of nano electrolytes was performed with the help of Raman Spectroscopy. Electrochemical study has shown an ionic conductivity of 0.16 Scm-1 at 600 °C for BSDC-carbonate in hydrogen atmosphere, which is higher than conventional electrolytes SDC and GDC under same conditions. In this article reasonably good ionic conductivity of BSDC-carbonate, at 600 °C, has also been achieved in air atmosphere which is comparatively greater than the conventional SDC and GDC electrolytes.
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| 7. |
- Akhtar, Ahmad Saleem, et al.
(författare)
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A portable and low-cost centrifugal microfluidic platform for multiplexed colorimetric detection of protein biomarkers
- 2023
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 1245
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Tidskriftsartikel (refereegranskat)abstract
- Cytokines play a very important role in our immune system by acting as mediators to put up a coordinated defense against foreign elements in our body. Elevated levels of cytokines in the body can signal to an ongoing response of the immune system to some abnormality. Thus, the quantification of a panel of cytokines can provide valuable information regarding the diagnosis of specific diseases and state of overall health of an individual. Conventional Enzyme Linked Immunosorbent Assay (ELISA) is the gold-standard for quantification of cytokines, however the need for trained personnel and expensive equipment limits its application to centralized laboratories only. In this context, there is a lack of simple, low-cost and portable devices which can allow for quantification of panels of cytokines at point-of-care and/or resource limited settings.Here, we report the development of a versatile, low-cost and portable bead-based centrifugal microfluidic platform allowing for multiplexed detection of cytokines with minimal hands-on time and an integrated colorimetric signal readout without the need for any external equipment. As a model, multiplexed colorimetric quantification of three target cytokines i.e., Tumor necrosis factor alpha (TNF-α), Interferon gamma (IFN-γ) and Interleukin-2 (IL-2) was achieved in less than 30 min with limits of detection in ng/mL range. The developed platform was further evaluated using spiked-in plasma samples to test for matrix interference. The ease of use, low-cost and portability of the developed platform highlight its potential to serve as a sample-to-answer solution for detection of cytokine panels in resource limited settings.
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| 8. |
- Akhtar, Ahmad Saleem, et al.
(författare)
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An integrated centrifugal microfluidic platform for multiplexed colorimetric immunodetection of protein biomarkers in resource-limited settings
- 2021
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Ingår i: Proceedings MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 947-948
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Konferensbidrag (refereegranskat)abstract
- The up- and down- regulation of inflammatory biomarkers such as cytokines can be indicative of several diseases such as primary cancers and/or metastatic tumors, as well as less serious conditions. For point-of-care clinical applications, the detection of these biomarkers requires a combination of a sensitive assay and multiplexing capabilities, together with fit-for-purpose signal transduction strategies. Here, we report the development of a versatile and cost-effective integrated centrifugal microfluidic platform compatible with resource-limited settings using nanoporous microbeads for immunoaffinity-based profiling of cytokines. With an automated colorimetric readout at the end, the platform allows for profiling of cytokines in < 30 mins.
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| 9. |
- Akhtar, Ahmad Saleem, et al.
(författare)
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Centrifugal microfluidic platform comprising an array of bead microcolumns for the multiplexed colorimetric quantification of inflammatory biomarkers at the point-of-care
- 2019
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Ingår i: 23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2019. - : Chemical and Biological Microsystems Society. ; , s. 1230-1231
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Konferensbidrag (refereegranskat)abstract
- The detection of panels of inflammatory biomarkers such as cytokines has potential for the rapid and specific diagnostic of several devastating diseases such as primary cancers and/or metastatic tumors, as opposed to less serious conditions. For point-of-care clinical applications, the detection of these biomarkers requires a combination of pg/mL sensitivities and multiplexing capabilities, coupled with fit-for-purpose signal transduction strategies. Here, we report the development of a versatile centrifugal microfluidic platform combined with nanoporous microbeads for immunoaffinity-based profiling of cytokines. The device allows sample and analyte multiplexing and detection limits below 1 ng/mL were achieved within 30 minutes, using colorimetric detection.
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| 10. |
- Akhtar, Ahmad Saleem
(författare)
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Centrifugal microfluidics-based point of care diagnostics at resource limited settings
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Advancements in medical diagnostics have allowed us to understand the underlying mechanism and treat the root cause for many diseases which had been causing morbidity and mortality up until this point in human history. Furthermore, many of the standard diagnostic procedures have now been transformed to provide answers at or near the point-of-care. However, the effects of these positive developments have not trickled down to the parts of our society which are considered underdeveloped and lack the necessary infrastructure and facilities. Diagnostics in such resource limited settings still lag behind and fail to provide the requisite healthcare. In order to translate the diagnostic solutions designed for central laboratories to resource limited settings, there are certain challenges that need to be addressed, such as portability, reduction in cost and ease-of-use, while keeping the sensitivity and specificity at the required level. The work presented in this thesis focuses on addressing some of these issues by using microfluidics to develop diagnostic platforms that are suitable to be used in resource limited settings. In paper I, a very low-cost and simple centrifugal microfluidic platform was developed to be used in settings which do not have a reliable supply of electricity. The platform uses a smartphone as a source of power and the sensors of the phone for speed control.In paper II, a portable and low-cost diagnostic platform was developed for multiplexed detection of biomarkers based on centrifugal microfluidics. The platform uses colorimetric detection and a simple readout method which does not require a spectrophotometer for quantification.In paper III, a platform was developed for COVID-19 diagnostics which combines centrifugal microfluidics with a novel bead-based strategy for signal enhancement. The platform uses fluorescent detection with a smartphone readout and has the capability to process up to 20 samples at the same time.In paper IV, as a follow up of paper III, a more advanced platform was developed for COVID-19 diagnostics which allows the operator to carry out nucleic acid amplification in a completely automated manner, from adding the sample to getting the final result.In paper V, an alternative method for detection of SARS-CoV-2 was developed using electrochemical biosensing. This work combines the electrochemical technique with a flexible printed circuit board for a rapid, amplification-free and label-free detection of target SARS-CoV-2 sequences.
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| 11. |
- Akhtar, Ahmad Saleem, et al.
(författare)
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Fully automated centrifugal microfluidic platform for COVID-19 detection using computer vision-based readout
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- COVID-19 pandemic made it evident that the world is unprepared for effectively tackling a pandemic resulting from an infectious disease. The conventional diagnostic methods for detection of infectious diseases were limited to centralized laboratories. As the burden of testing increased with the spread of the disease, the centralized testing facilities were strained for resources and personnel. These problems were further exacerbated in low- and middle-income countries where the health and transport infrastructure are not very well developed. To overcome this reliance on centralized testing and to facilitate decentralized testing, focus was shifted towards development of novel point-of-care diagnostic methods. We report the development of a fully automated centrifugal microfluidic platform that uses loop mediated isothermal amplification (LAMP) combined with computer vision-based readout for COVID-19 detection. The integrated platform allows sample to answer analysis at the push of a single button and can process 26 samples in 40 minutes. The platform performs a completely automated assay protocol involving heating, rotation and detection without the need for user intervention. A limit of detection of approximately 100 RNA copies in 10 µL reaction was achieved using RNA fragments spiked in water and similar results were obtained for artificial saliva samples.
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| 12. |
- Damiati, Samar, et al.
(författare)
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Flex Printed Circuit Board Implemented Grapene-Based DNA Sensor for Detection of SARS-CoV-2
- 2021
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Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 21:12, s. 13060-13067
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Tidskriftsartikel (refereegranskat)abstract
- Since the COVID-19 outbreak was declared a pandemic by the World Health Organization (WHO) in March 2020, ongoing efforts have been made to develop sensitive diagnostic platforms. Detection of viral RNA provides the highest sensitivity and specificity for detection of early and asymptomatic infections. Thus, this work aimed at developing a label-free genosensor composed of graphene as a working electrode that could be embedded into a flex printed circuit board (FPCB) for the rapid, sensitive, amplification-free and label-free detection of SARS-CoV-2. To facilitate liquid handling and ease of use, the developed biosensor was embedded with a user-friendly reservoir chamber. As a proof-of-concept, detection of a synthetic DNA strand matching the sequence of ORF1ab was performed as a two-step strategy involving the immobilization of a biotinylated complementary sequence on a streptavidin-modified surface, followed by hybridization with the target sequence recorded by the differential pulse voltammetric (DPV) technique in the presence of a ferro/ferricyanide redox couple. The effective design of the sensing platform improved its selectivity and sensitivity and allowed DNA quantification ranging from 100 fg/mL to 1 mu g/mL. Combining the electrochemical technique with FPCB enabled rapid detection of the target sequence using a small volume of the sample (5-20 mu L). We achieved a limit-of-detection of 100 fg/mL, whereas the predicted value was similar to 33 fg/mL, equivalent to approximately 5 x 10(5) copies/mL and comparable to sensitivities provided by isothermal nucleic acid amplification tests. We believe that the developed approach proves the ability of an FPCB-implemented DNA sensor to act as a potentially simpler and more affordable diagnostic assay for viral infections in Point-Of-Care (POC) applications.
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| 13. |
- Kazemzadeh, Amin, et al.
(författare)
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Mobile-LabDisc for Point-of-Care Diagnostics
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- At resource limited settings, point of care devices require a very low-cost, robust and easy to use platform that is preferably capable of automating and multiplexing intricate bioassays. We report on a mobile lab-disc platform that is specifically designed to meet the needs at resource- limited settings. It uses a smartphone as an electrical power source and a disposable, rigid and portable casing made of cardboard that securely accommodate the entire lab-disc system rotor, lightning and wiring and other accessories. The mobile lab-disc is light, less-expensive and functional at places where the electrical power infrastructure is not available. We show that the electrical energy stored in most mobile phones can be used for spinning a lab-Disc at up to 5500 rpm, a speed sufficient for most of the required functional steps in a bioassay including ELISA. We develop individual components of the mobile lab-disc system by experimentally conducting colorimetric assays using HRP and sandwich immunoassay. Finally, the full potential of the mobile lab-disc for integrating and multiplexing bioassays is demonstrated by measuring the hematocrit level in whole blood. The mobile phone-operated process integrates sample preparation i.e., blood-plasma separation, imaging and image analysis. The total cost of our prototype system for the tests, excluding the phone is ~$5, assuming that a lab-disc unit is worth $1.
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| 14. |
- Lapins, Noa, et al.
(författare)
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A smartphone powered centrifugal microfluidic platform for point-of-care diagnostics in resource limited settings
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The broad availability of smartphones has provided new opportunities to develop less expensive, portable and integrated point-of-care (POC) platforms. To date, many point-of-care devices have been developed that employ the computing power and the optical sensing capabilities available in smartphones. Here, a platform that consists of three main components is introduced: a portable housing, a centrifugal microfluidic disc and a mobile phone. The mobile phone supplies the electrical power and serves as an analysing system that captures and processes the test images. The housing made from cardboard serves as a platform to conduct tests and ensures the portability and rigidity of the platform while being extremely low-cost. The electrical energy stored in mobile phones was demonstrated to be adequate for spinning a centrifugal disc up to 3000 revolutions per minute (RPM), a rotation speed suitable for majority of centrifugal microfluidics-based bioassays. For controlling the rotational speed without the need for external circuitry, a combination of magnetic and acoustic tachometry using embedded sensors of the mobile phone was used. Experimentally, the smartphone-based tachometry was proven to be comparable with a standard laser-based tachometer. As a proof of concept, two applications were demonstrated using the portable platform: a colorimetric sandwich immunoassay to detect interleukin-2 (IL-2) and a fully automated measurement of hematocrit level integrating blood-plasma separation, imaging and image analysis. The low-cost platform weighing less than 150 grams operated by a mobile phone has the potential to meet the REASSURED criteria for advanced diagnostics in resource limited settings.
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| 15. |
- Lapins, Noa, et al.
(författare)
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Mobile-labdisc for point-of-care diagnostics at resource limited settings
- 2018
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Ingår i: 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018. - : Chemical and Biological Microsystems Society. - 9781510897571 ; , s. 1762-1764
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Konferensbidrag (refereegranskat)abstract
- Anyone carrying a smartphone has the potential access to an electrical power bank capable of spinning a lab-disc, a sensor for imaging and the processing power to analyze data. Here, exploit the electrical power stored in smartphones to introduce a smartphone operated centrifugal platform made of cardboard and a small motor to provide a low-cost, portable, sample-to-answer centrifugal diagnostic systems, specifically designed to meet the needs in resource-limited-settings. As a proof of principle, sandwich ELISA immunoassay for detection of interleukin-2 and hematocrit level measurement are demonstrated.
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| 16. |
- Soares, Ruben R. G., et al.
(författare)
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Point-of-care isothermal nucleic acid amplification platform for COVID-19 diagnostics in resource-limited settings
- 2021
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Ingår i: Proceedings MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 863-864
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Konferensbidrag (refereegranskat)abstract
- The demand for scalable, rapid and sensitive COVID-19 diagnostics is particularly pressing at present to help contain the spread of infection and prevent overwhelming the capacity of health systems. While high-income countries have managed to rapidly expand diagnostic capacities, such is not the case in resource-limited settings of low- to medium-income countries. We report the development of an integrated modular centrifugal microfluidic platform costing less than 250 USD to perform loop-mediated isothermal amplification (LAMP) of viral RNA directly from heat-inactivated nasopharyngeal swab samples. The platform was validated with a panel of 131 nasopharyngeal swab samples collected from symptomatic COVID-19 patients.
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| 17. |
- Soares, Ruben R. G., et al.
(författare)
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Sample-to-answer COVID-19 nucleic acid testing using a low-cost centrifugal microfluidic platform with bead-based signal enhancement and smartphone read-out
- 2021
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 21:15, s. 2932-2944
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Tidskriftsartikel (refereegranskat)abstract
- With its origin estimated around December 2019 in Wuhan, China, the ongoing SARS-CoV-2 pandemic is a major global health challenge. The demand for scalable, rapid and sensitive viral diagnostics is thus particularly pressing at present to help contain the rapid spread of infection and prevent overwhelming the capacity of health systems. While high-income countries have managed to rapidly expand diagnostic capacities, such is not the case in resource-limited settings of low- to medium-income countries. Aiming at developing cost-effective viral load detection systems for point-of-care COVID-19 diagnostics in resource-limited and resource-rich settings alike, we report the development of an integrated modular centrifugal microfluidic platform to perform loop-mediated isothermal amplification (LAMP) of viral RNA directly from heat-inactivated nasopharyngeal swab samples. The discs were pre-packed with driedn-benzyl-n-methylethanolamine modified agarose beads used to selectively remove primer dimers, inactivate the reaction post-amplification and allowing enhanced fluorescence detectionviaa smartphone camera. Sample-to-answer analysis within 1 hour from sample collection and a detection limit of approximately 100 RNA copies in 10 μL reaction volume were achieved. The platform was validated with a panel of 162 nasopharyngeal swab samples collected from patients with COVID-19 symptoms, providing a sensitivity of 96.6% (82.2-99.9%, 95% CI) for samples with Ct values below 26 and a specificity of 100% (90-100%, 95% CI), thus being fit-for-purpose to diagnose patients with a high risk of viral transmission. These results show significant promise towards bringing routine point-of-care COVID-19 diagnostics to resource-limited settings.
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| 18. |
- Urrutia Iturritza, Miren, et al.
(författare)
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An automated microfluidic diagnostics pipeline for infectious disease detection in low resource settings
- 2020
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Ingår i: MicroTAS 2020 - 24th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 1197-1198
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Konferensbidrag (refereegranskat)abstract
- While diagnostics are critical for accurate and timely diagnosis, gold-standard diagnostic tests are commonly high- performance laboratory-based tests that require multi-step protocols for complex sample processing and highly trained personnel, both scarce in low-resource settings. Here, we address the need for an easy-to-use, rapid and reliable diagnostic testing pipeline by presenting a solution combining open-source modular automation and automation compatible microfluidics, easily adaptable to a pipeline for infectious diseases diagnosis. We demonstrate an automation compatible microfluidics pipeline for Neisseria meningitidis diagnosis by on-chip nucleic acids isolation and isothermal amplification, as well as pathogen detection on a paper-based microarray.
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| 19. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 20. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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