| 1. |
- FOLKE, MIA, 0967-
(författare)
-
Measurements of Respiratory Carbon Dioxide
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Koldioxid är en central parameter för metabolismen i alla levande varelser. Hos människan regleras koldioxidhalten främst genom andningen. Därför är det viktigt att kunna mäta och övervaka koldioxidhalten i fysiologiska applikationer så väl inom sportmedicin som inom vården, till exempel på intensivvårdsavdelningar. Dessa mätningar kräver adekvat mätutrustning.Syftet med denna avhandling är att kritiskt granska föreslagna metoder för övervakning av andningsaktiviteten, att föreslå och utveckla förbättringar, samt att föreslå och utveckla nya applikationer för mätning av koldioxidhalten i utandningsluften med hjälp av en elektroakustisk sensor.Mätning av koldioxid i utandningsluften har den fördelen över andra föreslagna metoder för andningsövervakning att den även ger information om förhållandet i arteriellt blod då partialtrycket för koldioxid i slutet av ett andetag är lika stort som i artärblod hos lungfriska personer.Den föreslagna tekniken bygger på en elektroakustisk sensor som kan registrera och mäta koldioxidhalten i utandningsluften om fukt- och temperaturvariationer utjämnas med hjälp av filter. Den elektroakustiska sensorn består av en ultraljudssändare och en reflektor placerade i varsin ände av ett perforerat rör. Den elektriska impedansen i sensorn representerar molekylvikten inne i sensorkaviteten. Molekylmassan har ett linjärt förhållande till koldioxidhalten så länge övriga gaser hålls konstanta.Det faktum att partialtrycket av koldioxid i slutet av ett andetag kan mätas med den elektroakustiska sensorn gör den användbar i flera kliniska situationer om andra gaser inte kan påverka mätningarna.Partialtrycket av koldioxid i slutet av ett andetag har visat sig vara användbar som en indikator för mjölksyratröskeln då personens individuella mjölksyratröskel infaller då partialtrycket av koldioxid i slutet av ett andetag börjar minska. Det ger en ny applikation inom sportmedicin. På det sättet är det möjligt för en idrottare att mäta variationerna i sin mjölksyratröskel, i sin egen sport på daglig basis, vilket kan användas för att optimera arbetsintensiteten under träning och tävling. Trots att det elektroakustiska sensorsystemet inte är selektivt för koldioxid och därför påverkas även av förändringar i syre i utandningsluften har det visat sig fungera i denna applikation.
|
|
| 2. |
- Åstrand, Anders P, 1961-
(författare)
-
A Tactile Resonance Sensor System for Detection of Prostate Cancer ex vivo : Design and Evaluation on Tissue Models and Human Prostate
- 2014
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background The most common form of cancer among males in Europe and the USA is prostate cancer, PCa. Surgical removal of the prostate is the most common form of curative treatment. PCa can be suspected by a blood test for a specific prostate antigen, a PSA-test, and a digital rectal examination, DRE where the physician palpates the prostate through the rectum. Stiff nodules that can be detected during the DRE, and elevated levels of PSA are indications for PCa, and a reason for further examination. Biopsies are taken from the prostate by guidance of a transrectal ultrasound. Superficial cancer tumours can indicate that the cancer has spread to other parts of the body. Tactile resonance sensors can be used to detect areas of different stiffness in soft tissue. Healthy prostate tissue is usually of different stiffness compared to tissue with PCa.AimThe general aim of this doctoral thesis was to design and evaluate a flexible tactile resonance sensor system (TRSS) for detection of cancer in soft human tissue, specifically prostate cancer. The ability to detect cancer tumours located under the surface was evaluated through measurements on tissue phantoms such as silicone and biological tissues. Finally measurements on resected whole prostate glands were made for the detection of cancer tumours.Methods The sensor principle was based on an oscillating piezoelectric element that was indented into the soft tissue. The measured parameters were the change in resonance frequency, Δf, and the contact force F during indentation. From these, a specific stiffness parameter was obtained. The overall accuracy of the TRSS was obtained and the performance of the TRSS was also evaluated on tissue models made of silicone, biological tissue and resected whole human prostates in order to detect presence of PCa. Prostate glands are generally spherical and a special rotatable sample holder was included in the TRSS. Spherically shaped objects and uneven surfaces call for special attention to the contact angle between the sensor-tip and the measured surface, which has been evaluated. The indentation velocity and the depth sensitivity of the sensor were evaluated as well as the effect on the measurements caused by the force with which spherical samples were held in place in the sample holder. Measurements were made on silicone models and biological tissue of chicken and pork muscles, with embedded stiff silicone nodules, both on flat and spherical shaped samples. Finally, measurements were made on two excised whole human prostates.ResultsA contact angle deviating ≤ 10° from the perpendicular of the surface of the measured object was acceptable for reliable measurements of the stiffness parameter. The sensor could detect stiff nodules ≤ 4 mm under the surface with a small indentation depth of 0.4 to 0.8 mm.Measurements on the surface of resected human prostate glands showed that the TRSS could detect stiff areas (p < 0.05), which were confirmed by histopathological evaluation to be cancer tumours on, and under the surface.Conclusions A flexible resonance sensor system was designed and evaluated on soft tissue models as well as resected whole prostate glands. Evaluations on the tissue models showed that the TRSS can detect stiffer volumes hidden below the surface on both flat and spherical samples. The measurements on resected human prostate glands showed that PCa could be detected both on and under the surface of the gland. Thus the TRSS provides a promising instrument aimed for stiffness measurements of soft human tissue that could contribute to a future quantitative palpation method with the purpose of diagnosing cancer.
|
|
| 3. |
- Andersson, Roger, 1967-
(författare)
-
Monitoring principles for haemodialysis
- 2002
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with non-invasive monitoring techniques for haemodialysis. Three applications in particular have been investigated: Blood pressure measurements in the extra corporal circuit, the relationship between UV measurements and dialysate urea concentration and photoplethysmography (PPG) in haemodialysis patients.A non-invasive pressure sensor as an integrated part of the extracorporeal tube circuit was developed using modified cross-section tube geometry. The expansions of the modified tubes with different cross-sectional geometries were studied upon application of pressure, both experimentally and numerically, using the finite element method. Factorial design was used to study the relationship between pressure in the tube and force needed to restore the expanding tube to its original dimension. This investigation was performed for different tube cross-sectional geometries. A pressure sensor was designed, based on the previously obtained findings. The evaluation of the pressure sensor showed that the output corresponded well to applied pressure (R2=0.99).An UV-method for studying waste products in the dialysate has recently been developed by our research group. In the present study, it was investigated how the relationship between UV-absorption and dialysate urea concentration was affected by the treatment settings, patient anamnesis and prescribed pharmaceuticals. A mathematical model was proposed which includes these effects. Multiregression analysis indicated the possibility of performing individual estimates of urea concentration from UV-absorption.During haemodialysis, the patient's cardiovascular system is affected when excess fluid is extracted, which may result in blood pressure fluctuations. In the present study, a novel PPG method for monitoring haemodynamic changes during dialysis was investigated. The performed study indicates that PPG measurements relate to haemodynamic changes and may thus be useful in the patient monitoring. However, the relationship is complex and needs further studies.
|
|
| 4. |
|
|
| 5. |
- Baraldi, Enrico, Professor, 1970-, et al.
(författare)
-
Managing interorganizational interactions for social impact : A study of two antibiotics R&D networks
- 2022
-
Ingår i: Journal of Business Research. - : Elsevier. - 0148-2963 .- 1873-7978. ; 141, s. 264-278
-
Tidskriftsartikel (refereegranskat)abstract
- This paper relies on a comparative case study of two antibiotics R&D networks, ENABLE and CARB-X, to understand how interorganizational interactions can be managed to achieve social impact. In particular, we investigate (1) how particular management mechanisms and interorganizational interactions relate to the network's intended social impact, and (2) how these management mechanisms influence interorganizational interactions. We find that (1) the intended social impact influences the choice of management mechanisms from the very start of a partnership and orients the kind of interactions occurring within the network, and (2) that management mechanisms can shape the interactions unfolding in the network, but that the structural elements of these interactions also make these mechanisms more or less applicable to the network. We contribute to the Industrial Marketing & Purchasing (IMP) view with a model of managing networks building on the three concepts of: intended social impact, management mechanisms, and interorganizational interactions.
|
|
| 6. |
- Candefjord, Stefan, et al.
(författare)
-
Combining scanning haptic microscopy and fibre optic Raman spectroscopy for tissue characterization
- 2012
-
Ingår i: Journal of Medical Engineering & Technology. - : Taylor & Francis. - 0309-1902 .- 1464-522X. ; 36:6, s. 319-327
-
Tidskriftsartikel (refereegranskat)abstract
- The tactile resonance method (TRM) and Raman spectroscopy (RS) are promising for tissue characterization in vivo. Our goal is to combine these techniques into one instrument, to use TRM for swift scanning, and RS for increasing the diagnostic power. The aim of this study was to determine the classification accuracy, using support vector machines, for measurements on porcine tissue and also produce preliminary data on human prostate tissue. This was done by developing a new experimental set-up combining micro-scale TRMscanning haptic microscopy (SHM)for assessing stiffness on a micro-scale, with fibre optic RS measurements for assessing biochemical content. We compared the accuracy using SHM alone versus SHM combined with RS, for different degrees of tissue homogeneity. The cross-validation classification accuracy for healthy porcine tissue types using SHM alone was 6581%, and when RS was added it increased to 8187%. The accuracy for healthy and cancerous human tissue was 6770% when only SHM was used, and increased to 7277% for the combined measurements. This shows that the potential for swift and accurate classification of healthy and cancerous prostate tissue is high. This is promising for developing a tool for probing the surgical margins during prostate cancer surgery.
|
|
| 7. |
- Ciabuschi, Francesco, 1973-, et al.
(författare)
-
Joining Forces to Prevent the Antibiotic Resistance Doomsday Scenario : The Rise of International Multisectoral Partnerships as a New Governance Model
- 2020
-
Ingår i: Academy of Management Perspectives. - : Academy of Management. - 1558-9080 .- 1943-4529. ; 34:4, s. 458-479
-
Tidskriftsartikel (refereegranskat)abstract
- Humanity is facing a global threat caused by growing antibiotic resistance. If the current lack of innovation in antibiotics persists, we will face a doomsday scenario with drastic implications for society, health, and business worldwide. In this study, we examine international multisectoral partnerships (IMSPs), one of the policy interventions introduced to incentivize the antibiotic innovation necessary to avoid such a scenario. Based on insights from three recently launched antibiotics IMSPs, we present their key features and argue that such partnerships represent a novel type of organizational form and governance, different from others discussed in previous research. Specifically, antibiotics IMSPs are interorganizational structures showing great governance complexity, strong centralized control, strict boundaries, and formalization of roles and rules. We discuss how antibiotics IMSPs differ from other partnerships dealing, for instance, with the environmental global challenge, and their usefulness in other contexts where similar uncertain, risky, urgent, and complex tasks need to be faced. We conclude with implications for theory as well as for policy and managerial practice, along with avenues for future research.
|
|
| 8. |
- Ciabuschi, Francesco, 1973-, et al.
(författare)
-
Supporting innovation against the threat of antibiotic resistance : Exploring the impact of public incentives on firm performance and entrepreneurial orientation
- 2020
-
Ingår i: Journal of Business Research. - : Elsevier BV. - 0148-2963 .- 1873-7978. ; 112, s. 271-280
-
Tidskriftsartikel (refereegranskat)abstract
- Although there is an urgent need to find new antibiotics to fight growing antibiotic resistance, the development of antibiotics is at its lowest level ever. This innovation drought in the antibiotics industry is a challenge for managers, policy makers, and public health authorities. Currently, several strategies to incentivize antibiotic innovation are being considered, but their effects are unknown. Using the theoretical lens of the entrepreneurial orientation framework and Monte Carlo-based simulations on state-of-the-art pharmaceutical industry data, this study found that several incentives can increase the innovativeness of firms in this industry. However, the results show that these effects vary between incentives, between large and small firms, and across different research and development stages. This study analyzed these findings in the light of the entrepreneurial orientation framework and presents implications for theory, policy makers, and managers.
|
|
| 9. |
- Hallberg, Per, 1965-
(författare)
-
Applanation Resonance Tonometry for Intraocular Pressure Measurement
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Elevated intraocular pressure (IOP) is one of the major risk factors for glaucoma. Since glaucoma is a leading cause of blindness, reliable methods for measuring the IOP are important. This doctoral dissertation presents a new method, applanation resonance tonometry (ART), for measurement of IOP. The method is based on resonance sensor technology combined with the novel multipoint analysis of continuously sampled data of both contact force and contact area. The ART was evaluated in in vitro porcine-eye studies as well as in clinic on both healthy volunteers and patients. A new symmetric probe with a larger sensor tip and improved aligning light was developed and evaluated in vitro. It showed that the error from off-centring was highly reduced. The new ART probe, used as a biomicroscope device (ARTBiom) and as a handheld device (ARTHand), was further evaluated in a clinical study designed in accordance with the International Standard Organisation’s (ISO) requirement. Both the ARTBiom and the ARTHand met the precision set by the requirements. Laser surgery is a common way to correct vision. The biomechanical effect of photorefractive keratectomy (PRK) on IOP measurements was evaluated using Goldmann applanation tonometry (GAT) and ART in an in vitro study. Both methods were affected, but to a different extent. The flat contact probe of GAT, as compared with the convex tip of ART, and single point vs. multipoint approach, provide explanation to the ART advantage regarding measurement error of IOP after PRK. In conclusion, resonance sensor technology has made it possible to introduce a new multipoint method for measuring IOP, and the method is relevant for measuring IOP in humans. It may be possible to reduce errors in the clinical measurement of IOP with this new method, especially after corneal surgery. The ART has the potential to become a useful clinical instrument for IOP measurement.
|
|
| 10. |
- Jalkanen, Ville, 1978-
(författare)
-
Tactile sensing of prostate cancer : a resonance sensor method evaluated using human prostate tissue in vitro
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer is the most frequent type of cancer in men in Europe and the USA. The methods presently used to detect and diagnose prostate cancer are inexact, and new techniques are needed. Prostate tumours can be regarded as harder than the surrounding normal healthy glandular tissue, and therefore it is of interest to be able to reliably measure prostate tissue stiffness. In this dissertation the approach was to evaluate tactile resonance sensor technology and its ability to measure mechanical properties and to detect cancer in human prostate tissue. The tactile resonance sensor is based on a piezoelectric transducer element vibrating at its resonance frequency through a feedback circuit. A change in the resonance frequency is observed when the sensor contacts an object. This feature has been utilized to measure tissue stiffness variations due to various pathophysiological conditions. An impression-controlled tactile resonance sensor system was first used to quantify stiffness and evaluate performance on silicone. Then the sensor system was used on fresh human prostate tissue in vitro to measure stiffness using a combination of frequency change and force measurements. Significant differences in measured stiffness between malignant and healthy normal tissue were found, but there were large variations within the groups. Some of the variability was explained by prostate tissue histology using a tissue stiffness model. The tissue content was quantified at four depths in the tissue specimens with a microscope-image-based morphometrical method involving a circular grid. Numerical weights were assigned to the tissue data from the four depths, and the weighted tissue proportions were related to the measured stiffness through a linear model which was solved with a least-squares method. An increase in the proportion of prostate stones, stroma, or cancer in relation to healthy glandular tissue increased the measured stiffness. Stroma and cancer had the greatest effect and accounted for 90 % of the measured stiffness (45% and 45%, respectively). The deeper the sensor was pressed, the greater, i.e., deeper, volume it sensed. A sensing depth was extrapolated from the numerical weights for the measurements performed at different impression depths. Horizontal surface tissue variations were studied by altering the circular grid size relative to the contact area between the sensor tip and the tissue. The results indicated that the sensing area was greater than the contact area. The sensor registered spatial tissue variations. Tissue density-related variations, as measured by the frequency change, were weakly significant or non-significant. The measured force registered elastic-related tissue variations, to which stroma and cancer were the most important variables. A theoretical material-dependent linear relation was found between frequency change and force from theoretical models of frequency change and force. Tactile resonance sensor measurements on prostate tissue verified this at small impression depths. From this model, a physical interpretation was given to the parameters used to describe stiffness. These results indicate that tactile resonance sensor technology is promising for assessing soft tissue mechanical properties and especially for prostate tissue stiffness measurement with the goal of detecting prostate cancer. However, further studies and development of the sensor design must be performed to determine the full potential of the method and its diagnostic power. Preferably, measurements of tissue mechanical properties should be used in combination with other methods, such as optical methods, to increase the diagnostic power.
|
|
