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The buildings and construction sector account for a significant part of the total energy use and related greenhouse gas emissions. However, climate change mitigation often becomes secondary or completely disregarded in building design assessment as the primary concern of building owners are economic tenability. Therefore, this study introduces an Extended Life Cycle Cost Assessment that include monetary evaluation of climate risk and opportunities in terms of Social Cost of Carbon (SCC). SCC could function as a tax to promote climate change mitigation within e.g. the construction industry. The purpose is to provide a more holistic assessment approach that is easy to relate to if economic tenability is of primary concern in decision making, which can be used to assess building design. Return on invested greenhouse gas emissions is used as an additional or standalone indicator for climate change mitigation. The introduced approach is exemplified by a case study where renovation and new construction are compared with keeping buildings in its original design. The case study show that with or without a flat greenhouse gas tax, renovation is the most climate and cost efficient alternative.

Energy efficiency investments in existing buildings are an effective way of reducing the environmental impact of the building stock. Even though policies in the European Union and elsewhere promote a unilateral focus on operational energy reduction, scientific studies highlight the importance of applying a life cycle perspective to energy refurbishment. However, life cycle assessment is often perceived as being complicated and the results difficult to interpret by the construction sector. There is also a lack of guidelines regarding the sustainable ratio between the embodied and accumulated operational impact. The scope of this study is to introduce a life cycle assessment method for building refurbishment that utilizes familiar economic performance tools, namely return on investment and annual yield. The aim is to use the introduced method to analyze a case building with a sustainability profile. The building was refurbished in order to reduce its operational energy use. The introduced method is compatible with a theory of minimum sustainable environmental performance that may be developed through backcasting from defined energy and GHG emissions objectives. The proposed approach will hopefully allow development of sustainable refurbishment objectives that can support the choice of refurbishment investments.

Improving energy efficiency in the existing buildings stock is essential to limit climate change and the economic assessment of measures are traditionally only based on the reduction of energy costs: However, future financial benefits of limiting climate change are rarely included in the evaluation of refurbishment investments. Although, the costs associated with global warming are expected to be extensive. This study introduces a method for the financial evaluation of energy efficiency investments that merge the reduction of life cycle energy costs with the reduction of future climate induced costs. A case study is used to exemplify the method. The case study shows that when reduced future costs due to mitigated life cycle greenhouse gas emissions are included in the analysis, the ranking between different measures can change and traditionally non-profitable measures may become financially sound investments. The introduced Economy+ indicator is shown to be an accessible performance measure to assess building refurbishment and may also be used in the design stage of new construction. (C) 2019 The Authors. Published by Elsevier B.V.

This study applies an environmental return on investment approach to evaluate building refurbishment from a life cycle perspective. The used methodology focuses on the changes introduced by refurbishment, i.e. added embodied environmental impact and changed operational environmental impact, from a life cycle perspective with the technical service life of the refurbishment measure as a time limit. The methodology is applied to a case study in Umeå, located 455 km south of the Arctic Circle, with a unique set of data on reduction in operational energy. The result show the environmental impact, energy (Joule) and GWP (CO2-eq), in terms of environmental return on investment of the case study refurbishment measures. The case study shows that the methodology is a useable approach to compare refurbishment measures from a life cycle perspective. It is possible to use the methodology as a tool at an early stage in planning of sustainable building refurbishment from a life cycle perspective. For a widespread use of a tool based on an environmental return on investment approach, further research on guidelines for sustainable environmental return on investment values is required.

In Sweden, the national building code (BBR) stipulates the specific energy use as an indicator to verify whether a newbuilding is complying with its design-phase energy performance values. However, previous studies have shown that there may belarge differences between the calculated specific energy and the actual monitored energy use. The differences are attributed tovarious reasons including the actual energy behaviour of the occupants as compared to the standard values used in thesimulations. This may lead to disputes between the client and the contractor on the responsibility of meeting the energyrequirements.In this study an adapted version of Delphi methodology was used to understand the building professionals’ view on variousindicators used to verify building energy performance. The study showed that professionals are concerned with the use of specificenergy as an indicator in the building procurement process as they do not have control over the occupants’ energy behaviour.Majority of the professionals expressed a large confidence in the average U-value of the building, component U-values and thespecific heat loss figure by the Swedish center for zero-energy buildings as indicators of building energy performance.

Tumors in the human prostate are usually stiffer compared to surrounding non-malignant glandular tissue, and tactile resonance sensors measuring stiffness can be used to detect prostate cancer. To explore this further, we used a tactile resonance sensor system combined with a rotatable sample holder where whole surgically removed prostates could be attached to detect tumors on, and beneath, the surface ex vivo. Model studies on tissue phantoms made of silicone and porcine tissue were performed. Finally, two resected human prostate glands were studied. Embedded stiff silicone inclusions placed 4 mm under the surface could be detected in both the silicone and biological tissue models, with a sensor indentation of 0.6 mm. Areas with different amounts of prostate cancer (PCa) could be distinguished from normal tissue (p < 0.05), when the tumor was located in the anterior part, whereas small tumors located in the dorsal aspect were undetected. The study indicates that PCa may be detected in a whole resected prostate with an uneven surface and through its capsule. This is promising for the development of a clinically useful instrument to detect prostate cancer during surgery.

Prostate cancer (PCa) is the most common form of cancer among the male population in Europe and the USA. PCa can be suspected by a blood test for a specific prostate antigen, a PSA-test, followed by a digital rectal examination (DRE). The objective with the DRE is to investigate the presence of stiff nodules on the prostate. Stiff nodules can indicate PCa and biopsies are taken from the suspicious parts of the prostate using guidance of a transrectal ultrasound. Microscopic evaluation of the biopsies is used for final diagnosis. Superficial tumor growth on, and beneath the surface of the gland is of special interest as it suggests that the cancer has spread to other parts of the body.

Tactile resonance sensors can be used to distinguish between areas of different stiffness in soft tissue. The aim was to detect tumors on, and beneath the surface of a whole human prostate ex vivo.

A tactile resonance sensor system (TRSS) based on a piezoelectric resonance sensor and a force sensor has been used to detect areas with increased stiffness in soft tissue. The TRSS has a rotatable sample holder for measurements on spherical shaped samples. Stiffness measurements were made on samples of porcine muscle tissue with embedded stiff silicone nodules placed under the surface. Further measurements were made on a resected whole human prostate with PCa.

The results showed that through the measured stiffness parameter, the stiff silicone nodules placed down to 4 mm under the surface could be detected. The measurements on the prostate showed that elevated values of the stiffness parameter correlated (p < 0.05) with areas in the anterior of the prostate where cancer tumors were detected by histopathological evaluation. The tumors were significantly stiffer than the healthy tissue in the dorsal region.

The results are promising for further development of a clinically useful instrument to detect superficial PCa.

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.

Aim

The 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.

Results

A 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. 

Background

Prostate cancer (PCa) is the most common form of cancer among males in Europe and in the USA and the most common curative treatment is removal of the prostate, i.e. prostatectomy. After the removal, the prostate is histopathologically analysed. One area of interest is to examine the capsule of the prostate, as tumours on and near the surface can indicate that the PCa has spread to other parts of the body. There are no current methods to examine the surface of the prostate at the time of surgery. Tactile resonance sensors can be used for detecting areas of different stiffness in soft tissue. Human prostate tissue affected by cancer is usually stiffer than healthy tissue, and for this purpose a tactile resonance sensor was developed. The aim of this study was to investigate the depth at which embedded stiffer volumes could be detected, using soft tissue phantoms.

Methods

With the tactile resonance sensor used in this study, the shift of the resonance frequency and the force at contact with tissue can be measured, and combined into a tissue stiffness parameter. The detection sensitivity of the sensor at impression depths, 0.4 and 0.8 mm, was measured for detection of an inserted nodules of stiff silicone in softer silicone and in chicken muscle tissue, mimicking prostate tissue with cancer tumours.

Results

Measurements on the silicone samples detected the hidden stiffer object at a depth of 1-4 mm with a difference in the stiffness parameter of 80 – 900 mN/kHz (p < 0.028, n = 48). At the depth 5-6 mm the difference was smaller but still significant < 30 mN/kHz (p < 0.05, n = 24). For the measurements on chicken muscle, the detectable depth was 4 mm (p < 0.05, n = 24).

Conclusion

This model study suggests that, with only a small impression depth of ≤ 1 mm, the resonance sensor system described here can detect stiffness variations located at least 4 mm in silicone and chicken muscle, mimicking tumours in prostate tissue.

Human tissue stiffness can vary due to different tissue conditions such as cancer tumours. Earlier studies show that stiffness may be detected with a resonance sensor that measures frequency shift and contact force at application. Through the frequency shift and the contact force, a tissue stiffness parameter can be derived. This study evaluated how the probe application angle and indentation velocity affected the results and determined the maximum parameter errors. The evaluation was made on flat silicone discs with specified hardness. The frequency shift, the force and the stiffness parameter all varied with contact angle and indentation velocity. A contact angle of ≤10° was acceptable for reliable measurements. A low indentation velocity was recommended. The maximum errors for the system were <1.1% of the measured values. It was concluded that contact angle and indentation velocity have to be considered in the clinical setting. The angular dependency is especially important in clinical use for studying stiffness of human soft tissue, e.g. in prostate cancer diagnosis.