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  • 1.
    Alsmo, Thomas
    et al.
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Holmberg, Sture
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Causes of Poor Air Quality in Swedish Schools2006Conference paper (Refereed)
    Abstract [en]

    This literature survey distinguishes between building and other factors influencing air quality. It does not identify building factors sufficient to account for occupant complaints. It concludes that buildings are often blamed for adverse health effects without sufficient grounds. The risk is there will be too much focusing on the wrong underlying problem when remedying so-called sick buildings. The study shows the importance of ensuring that factors independent of the school building, including the choices of environments and activities, are important for the indoor environment.

  • 2.
    Berglund, Martina
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Karltun, Johan
    Högskolan i Jönköping, JTH.
    Schedulers’ work content – a quantified analysis2006Conference paper (Refereed)
  • 3.
    Brenning, Magnus
    et al.
    KTH, School of Technology and Health (STH).
    Olander, Björn
    KTH, School of Technology and Health (STH).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering.
    Vennberg, Johan
    KTH, School of Technology and Health (STH).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering. 2Laboratory for communication networks, School of Electrical Engineering, KTH.
    NeTraWeb - A Web-Based Traffic Flow Performance Meter2006In: 4th Swedish National Computer Networking Workshop SNCNW 2006, 2006Conference paper (Refereed)
    Abstract [en]

    This paper presents a web-based traffic flow performance meter. The NeTraWeb tool configures and automates the measurement activities, including storage and presentation of the main performance parameters.

  • 4.
    Brolin, Karin
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Nordberg, Axel
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Stability and fibre reinforced adhesive fixation of vertebral fractures in the upper cervical spine2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, p. 151-152Article in journal (Refereed)
  • 5.
    Cheng, Kimberley
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Koeck, Philip J. B.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Elmlund, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Idakieva, Krassimira
    Parvanova, Katja
    Schwarz, Heinz
    Ternström, Tomas
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Comparison of the two Rapana thomasiana Hemocyanin isoforms: RtH1 and RtH22006In: Proc 16. International Microscopy Conference, 2006Conference paper (Refereed)
  • 6.
    Cheng, Kimberley
    et al.
    Department of Biosciences at NOVUM, Karolinska Institutet and School of Technology and Health, Royal Institute of Technology, S-141 57 Huddinge, Sweden.
    Koeck, Philip J. B.
    Department of Biosciences at NOVUM, Karolinska Institutet and School of Technology and Health, Royal Institute of Technology, S-141 57 Huddinge, Sweden.
    Elmund, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Ternström, Tomas
    Schwarz, Heinz
    Idakieva, Krassimira
    Parvanova, Katja
    Rapana thomasiana hemocyanin (RtH): Comparison of the two isoforms, RtH1 and RtH2, at 19 Å and 16 Å resolution2006In: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 37, no 6, p. 566-576Article in journal (Refereed)
    Abstract [en]

    Three-dimensional (3D) reconstructions of the two 8.4 MDa Rapana thomasiana hemocyanin isoforms, RtH1 and RtH2, have been obtained by cryoelectron microscopy of molecules embedded in vitreous ice and single particle image processing. The final 3D structures of the RtH1 and RtH2 didecamers at 19 angstrom and 16 angstrom resolution, respectively, are very similar to earlier reconstructions of gastropodan hemocyanins, revealing structural features such as the obliquely oriented subunits, the five- and two-fold symmetrical axes. Three new interactions are defined; two of them connecting the arch and the wall while the third is formed between the collar and the wall. The collar-wall connection and one of the arch-wall connections are positioned between two individual subunit dimers, while the second arch-wall connection is located between two subunits within the subunit dimer. All three interactions establish connections to the first tier of the wall. Furthermore, for each interaction we have allocated two first tier functional units most likely involved in forming the connections.

  • 7.
    Elmlund, Hans
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Baraznenok, Vera
    Division of Metabolic Diseases, Karolinska Institutet.
    Lindahl, Martin
    Department of Molecular Biophysics, Lund University.
    Samuelsen, Camilla O.
    Department of Genetics, Institute of Molecular Biology, Copenhagen.
    Koeck, Philip J. B.
    KTH, School of Technology and Health (STH).
    Holmberg, Steen
    Department of Genetics, Institute of Molecular Biology, Copenhagen.
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Gustafsson, Claes M.
    Division of Metabolic Diseases, Karolinska Institutet.
    The cyclin-dependent kinase 8 module sterically blocks Mediator interactions with RNA polymerase II2006In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 103, no 43, p. 15788-15793Article in journal (Refereed)
    Abstract [en]

    CDK8 (cyclin-dependent kinase 8), along with CycC, Med12, and Med13, form a repressive module (the Cdk8 module) that prevents RNA polymerase II (pol II) interactions with Mediator. Here, we report that the ability of the Cdk8 module to prevent pol II interactions is independent of the Cdk8-dependent kinase activity. We use electron microscopy and single-particle reconstruction to demonstrate that the Cdk8 module forms a distinct structural entity that binds to the head and middle region of Mediator, thereby sterically blocking interactions with pol II.

  • 8. Gillies, P.
    et al.
    Marshall, I.
    Asplund, Maria L M
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Winkler, P.
    Higinbotham, J.
    Quantification of MRS data in the frequency domain using a wavelet filter, an approximated Voigt lineshape model and prior knowledge2006In: NMR in Biomedicine, ISSN 0952-3480, E-ISSN 1099-1492, Vol. 19, no 5, p. 617-626Article in journal (Refereed)
    Abstract [en]

    Quantification of MRS spectra is a challenging problem when a large baseline is present along with a low signal to noise ratio. This work investigates a robust fitting technique that yields accurate peak areas under these conditions. Using simulated long echo time 1H MRS spectra with low signal to noise ratio and a large baseline component, both the accuracy and reliability of the fit in the frequency domain were greatly improved by reducing the number of fitted parameters and making full use of all the known information concerning the Voigt lineshape. Using an appropriate first order approximation to a popular approximation of the Voigt lineshape, a significant improvement in the estimate of the area of a known spectral peak was obtained with a corresponding reduction in the residual. Furthermore, this improved parameter choice resulted in a large reduction in the number of iterations of the least-squares fitting routine. On the other hand, making use of the known centre frequency differences of the component resonances gave negligible improvement. A wavelet filter was used to remove the baseline component. In addition to performing a Monte Carlo study, these fitting techniques were also applied to a set of 10 spectra acquired from healthy human volunteers.Again, the same reduced parameter model gave the lowest value for X2 in each case.

  • 9.
    Govind, Satish C.
    et al.
    Bhagwan Mahavir Jain Heart Center, Bangalore, India.
    Roumina, S.
    Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, J.
    Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Ramesh, S. S.
    Bhagwan Mahavir Jain Heart Center, Bangalore, India.
    Saha, S. K.
    Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Differing myocardial response to a single session of hemodialysis in end-stage renal disease with and without type 2 diabetes mellitus and coronary artery disease2006In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 4, no 9Article in journal (Refereed)
    Abstract [en]

    Background: Though hemodialysis (HD) acutely improves cardiac function, the impact of background diseases like coronary artery disease (CAD) and Type 2 diabetes (DM) in the setting of end-stage renal disease (ESRD) is not known. Tissue velocity echocardiography (TVE) offers a fast choice to follow changes in myocardial function after HD in ESRD with concomitant DM and/or CAD. Methods: 46 subjects (17 with ESRD, Group 1; 15 with DM, Group 2; 14 with DM+CAD, Group 3) underwent standard and TVE prior to and shortly after HD. Besides standard Doppler variables, regional myocardial systolic and diastolic velocities, as well as systolic strain rate were post processed. Results: Compared with pre-HD, post-HD body weight (kg) significantly decreased in all the three groups (51 ± 9 vs. 48 ± 8, 62 ± 10 vs.59 ± 10, and 61 ± 9 vs. 58 ± 9 respectively; all p < 0.01). Left ventricular end diastolic dimensions (mm) also decreased post- HD (46 ± 5 vs. 42 ± 7, 53 ± 7 vs. 50 ± 7, 51 ± 7 vs. 47 ± 8 respectively; all p < 0.01). Regional longitudinal peak systolic velocity in septum (cm/s) significantly increased post-HD in Group 1(5.7 ± 1.6 vs. 7.2 ± 2.3; p < 0.001) while remained unchanged in the other two groups. Similar trends were noted in other left ventricular walls. When the myocardial velocities (cm/s) were computed globally, the improvement was seen only in Group 1 (6.3 ± 1.5 vs. 7.9 ± 2.0; p < 0.001). Global early regional diastolic velocity (cm/s) improved in Group 1, remained unchanged in Group 2, while significantly decreased in Group 3(-5.9 ± 1.3 vs. -4.1 ± 1.8; p < 0.01). Global systolic strain rate (1/sec) increased in the first 2 Groups but remained unchanged (-0.87 ± 0.4 vs. -0.94 ± 0.3; p = ns) in Group 3. Conclusion: A single HD session improves LV function only in ESRD without coexistent DM and/or CAD. The present data suggest that not only dialysis-dependent changes in loading conditions but also co-existent background diseases determine the myocardial response to HD.

  • 10.
    Granroth, Marko
    et al.
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Holmberg, Sture
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Health and productivity in commercial buildings: thermal and hygienic aspects2006Conference paper (Refereed)
  • 11.
    Granroth, Marko
    et al.
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Holmberg, Sture
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Ventilation Strategy to improve health and productivity conditions2006In: HB - Heal. Build.: Creating Heal. Indoor Environ. People, Proc., 2006, p. 421-424Conference paper (Refereed)
    Abstract [en]

    This paper was mainly based on a literature review and focused on control of emissions and on thermal comfort conditions in office buildings. The ultimate goal was to identify optimal conditions for both human health and work productivity in office room environments. Good indoor air quality (IAQ) was to be achieved at low emission rates and correct indoor air temperature. Different ventilation and air conditioning strategies were evaluated and compared. Both energy and environmental aspects were considered. Analyses were made for emission rates of various indoor sources such as outdoor pollution, construction materials, furnishings, office-equipment and consumer products.

  • 12.
    Granroth, Marko
    et al.
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Holmberg, Sture
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Ventilation Strategy to Improve Health and Productivity in Swedish Offices2006In: Healthy Buildings, 4-8 June, Lisbon, Portugal, 2006: Vol IV, Finland: International Society of Indoor Air Quality and Climate (ISIAQ) , 2006, p. 421-424Conference paper (Refereed)
    Abstract [en]

    This paper was mainly based on a literature review and focused on control of emissions and on thermal comfort conditions in office buildings. The ultimate goal was to identify optimal conditions for both human health and work productivity in office room environments. Good indoor air quality (IAQ) was to be achieved at low emission rates and correct indoor air temperature. Different ventilation and air conditioning strategies were evaluated and compared. Both energy and environmental aspects were considered. Analyses were made for emission rates of various indoor sources such as outdoor pollution, construction materials, furnishings, office-equipment and consumer products. 

  • 13.
    Guha, Jaideep
    et al.
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Holmberg, Sture
    KTH, School of Technology and Health (STH), Fluid and Climate Technology (closed 20090101).
    Effectivity of a Suction Cylinder as Ventilation Equipment2006Conference paper (Refereed)
    Abstract [en]

    This paper proposes to use free wind to create suction pressure within a ventilation duct without consuming commercial energy. Like an ejector pump it creates suction pressure placed above the ventilation exhaust, which is used to draw exhaust air from the ventilation system. Discussing the possibilities of this suction cylinder concept in ventilation system is the objective of this paper. Here, a mathematical model was deduced for a suction cylinder and through CFD (Computational Fluid Dynamic) technique result was simulated later compared with theoretical model. GAMBIT was used as a preprocessor and for processing FLUENT, a commercial CFD code, was used for the simulation. Preliminary result clearly shows the positive advantages of using a suction cylinder as ventilation equipment.

  • 14.
    Haasl, Sjoerd
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Persson, Katrin
    Johander, Per
    3D packaging concept for inertial sensors2006In: Proceedings Eurosensors XX, Göteborg, Sweden, 2006, Vol. I, p. 192-193Conference paper (Refereed)
  • 15.
    Halldin, Peter
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Hedenstierna, Sofia
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Brolin, Karin
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Finite element analysis of the effects of head-supported mass on neck responses: Complete phase three report, united states army european research office of the U.S.army2006Report (Refereed)
    Abstract [en]

    The objectives for the whole project were to: I. determine the relationships between head supported mass and the risk of neck injuries. The results should be used in a Graphical user interface. In this phase three report has also the Graphical User Interface (GUI) been evaluated and the question about the how the muscle activation affect the injury risk. II. to develop and implement a 3D numerical muscle model. Results: I. The KTH neck model has successfully been used to generate results for the GUI. Results from all simulations have been reported and sent to Titan Corporation that is contracted by USAARL to program the GUI. The GUI that uses an interpolation method to calculate the neck injury risk for a general helmet with a user defined HSM configuration shows to give realistic interpolated values compared to the FE model of the neck. II. The 3D muscle model for the cervical spine includes 22 pairs of muscles. The solid muscle model showed to stabilize the vertebral column better than the spring muscle model. The model is still under evaluation and need further validation to be used in the HSM evaluation project.

  • 16.
    Hayashi, Shirley Yumi
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lind, Britta
    Department of Clinical Physiology, Karolinska Institutet, Karolinska University Hospital.
    Seeberger, Astrid
    Division of Baxter Novum and Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet.
    Mazza do Nascimento, Marcelo
    Division of Baxter Novum and Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet.
    Lindholm, Bengt J.
    Division of Baxter Novum and Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Analysis of mitral annulus motion measurements derived from M-mode, anatomic M-mode, tissue Doppler displacement, and 2-dimensional strain imaging2006In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 19, no 9, p. 1092-1101Article in journal (Refereed)
    Abstract [en]

    Background: Left ventricular longitudinal shortening plays an important role in cardiac contraction and can be measured by the mitral annulus motion (MAM) toward the cardiac apex. MAM can be evaluated by conventional M-mode, anatomic M-mode (AM-mode), tissue Doppler displacement (TDD), and 2-dimensional strain imaging (2DSI). Objective: The aim of the study was to compare these 4 different methods for measuring MAM. Methods: MAM was evaluated in 25 patients by M-mode, AM-mode, TDD, and 2DSI. Two walls (septal and lateral) in apical 4-chamber view were analyzed. Results. The angle correction between M-mode and AM-mode was significantly higher in the lateral wall (septum 2.2+/-1.6 vs lateral 4.1+/-1.6 degrees, P<0.01). However, with angle correction up to 8 degrees, the measurements obtained were not significantly different from those obtained by M-mode. No significant differences were found among 2DSI. M-mode, and AM-mode either, although all of them were significantly higher in comparison with TDD measurements in both septal (M-mode [11.0 +/- 2.4 nun], AM-mode [11.8 +/- 2.4 mm], 2DSI [11.0 +/- 3.4 mm] vs TDD [9.2 +/- 3.3 mm], P<.01) and lateral (M-mode [11.9 +/- 2.3 min], AM-mode [12.4 +/- 2.8 mm], 2DSI [10.4 +/- 3.9 mm] vs TDD [8.9 +/- 3.0 mm], P<.05) walls. The +/- 2SD variation from the mean difference in septal and lateral walls were, respectively, between: M-mode and TDD, -2.4 to 5.9 and -2.2 to 8.2 mm; M-mode and 2DSI, -5.7 to 5.7 and -5.8 to 8.7; AM-mode and TDD, -2.5 to 5.6 and -2.7 to 9.6; AM-mode and 2DSI, -5.7 to 5.87 and -5.9 to 9.8 and TDD and 2DSI, -3.2 to 6.6 and -5.3 to 8.4. Conclusions: AM-mode and M-mode measurements did not differ significantly. Despite the good correlation among all methods they were not interchangeable. TDD measurements were significantly lower than M-mode, AM-mode, and 2DSI measurements. M-mode and AM-mode are angle dependent and can, therefore, underestimate or overestimate MAM. The new method of 2DSI is promising because it tracks natural acoustic markers and is not angle dependent and, therefore, measures the true local tissue motion.

  • 17.
    Hayashi, Shirley Yumi
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Rohani, Morteza
    Department of Clinical Physiology, Karolinska Institutet, Karolinska University Hospital.
    Lindholm, Bengt
    Division of Baxter Novum, Department of Clinical Science, Karolinska University Hospital.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lind, Britta
    Department of Clinical Physiology, Karolinska Institutet, Karolinska University Hospital.
    Barany, Peter
    Division of Renal Medicine, Karolinska Institutet, Karolinska University Hospital.
    Alvestrand, Anders
    Division of Renal Medicine, Karolinska Institutet, Karolinska University Hospital.
    Seeberger, Astrid
    Division of Renal Medicine, Karolinska Institutet, Karolinska University Hospital.
    Left ventricular function in patients with chronic kidney disease evaluated by colour tissue Doppler velocity imaging2006In: Nephrology, Dialysis and Transplantation, ISSN 0931-0509, E-ISSN 1460-2385, Vol. 21, no 1, p. 125-132Article in journal (Refereed)
    Abstract [en]

    Background. Cardiovascular disease is the leading cause of death in chronic kidney disease (CKD) patients. Tissue Doppler velocity imaging (TVI) is a new objective method that accurately quantifies myocardial tissue velocities, deformation, time intervals and left ventricular (LV) filling pressure. In this study, TVI was compared with conventional echocardiography for the assessment of left ventricular (LV) function in pre-dialysis patients with different stages of CKD. The results obtained by TVI were used to analyse possible relationships between LV function and clinical factors such as hyperparathyroidism and hypertension that could influence LV function.

    Methods. Conventional echocardiography and TVI images were recorded in 40 patients (36 men and 4 women, mean age 60 +/- 14 years, range 28-80 years) and in 27 healthy controls (21 men and 6 women, mean age 58 +/- 17 years, range 28-82 years). Twenty-two patients had mild/moderate CKD (CCr > 29 ml/min; Group 1) and 18 patients had severe CKD (CCr <= 29 ml/min; Group 2). Using TVI, the myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVCv), peak systole (PSv), early (E') and late (A') diastolic filling velocities as well as strain rate (SR), mitral annulus displacement, isovolumetric relaxation time (IVRT) and LV filling pressure were estimated using TVI. The average of six LV wall measurements was used to evaluate LV global function.

    Results. Using TVI, we were able to identify significantly more patients with diastolic dysfunction than using conventional echocardiography (33 vs 26, P < 0.05). There was no difference in the prevalence of diastolic dysfunction between Group 1 and 2. However, using TVI, Group 2 CKD patients had lower E' velocities (6.2 +/- 1.9 vs 8.0 +/- 2.9 cm/s, P < 0.05) and higher IVRT (137.4 +/- 13 vs 88.2 +/- 26 ms, P < 0.001) in comparison with controls, indicating more accentuated diastolic dysfunction. Systolic blood pressure (SBP) was associated with E' velocities (rho = -0.68, P < 0.005) and E'/A' was strongly associated with SBP (rho = -0.60; P < 0.01) and PTH (rho = -0.64, P < 0.005) in Group 2. Using conventional echocardiography, there was no difference in the prevalence of systolic and diastolic dysfunction between patients with and without LVH. However, using TVI, patients with LVH had significantly lower IVCv (2.8 +/- 1.3 vs 3.8 +/- 1.5 and 3.8 +/- 1.5 cm/s, P < 0.05) and PSv (5.5 +/- 1.0 vs 6.3 +/- 1.2 and 6.4 +/- 1.3 cm/s, P < 0.05) compared with patients without LVH and controls, and they also had lower E' velocities (7.1 +/- 2.7 vs 8.0 +/- 2.9 cm/s, P < 0.05) compared with controls, indicating disturbances in systolic and diastolic left ventricular function.

    Conclusions. TVI provided additional information on left ventricular function in CKD patients. In patients with advanced renal failure, TVI revealed more accentuated diastolic dysfunction associated with increased systolic blood pressure (SBP) and increased levels of PTH. TVI also demonstrated disturbances in contractility and contraction in patients with LVH, which could not be detected by conventional echocardiography.

  • 18.
    Hedenstierna, Sofia
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Halldin, Peter
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Brolin, Karin
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Development and evaluation of a continuum neck muscle model2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no Supplement 1, p. 150-Article in journal (Refereed)
  • 19. Hegyesi, G.
    et al.
    Imrek, J.
    Kalinka, G.
    Molnar, J.
    Novak, D.
    Vegh, J.
    Balkay, L.
    Emri, M.
    Kis, S. A.
    Molnar, G.
    Tron, L.
    Valastyan, I.
    Bagamery, I.
    Bukki, T.
    Rozsa, S.
    Szabo, Z.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ethernet based distributed data acquisition system for a small animal PET2006In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 53, no 4, p. 2112-2117Article in journal (Refereed)
    Abstract [en]

    We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8 x 8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer including a digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system and coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and generates a time stamp with a coincidence resolution of less than 2 us. The data acquisition system is based on Ethernet network and is highly scalable in size and performance.

  • 20.
    Hegysei, G.
    et al.
    Institute of Nuclear Research of the Hungarian Academy of Sciences.
    Imrek, J.
    Institute of Nuclear Research of the Hungarian Academy of Sciences.
    Valastyán, Iván
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ethernet based distributed data acquistion system for small animal PET2006In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 53, no 4Article in journal (Refereed)
    Abstract [en]

    We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8times8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer and digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system, coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and it generates a time stamp with a coincidence resolution of 2 to 3 ns. The data acquisition System is based on Ethernet network and is highly scalable in size and performance

  • 21.
    Ho, Johnson
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    An automatic method to generate a patient specific finite element head model2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no 1, p. S428-Article in journal (Refereed)
  • 22.
    Ho, Johnson
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Investigation of the Dynamic Response Contribution of Vasculature in a 3D Finite Element Head Model2006Conference paper (Refereed)
  • 23. Holm, Peter J.
    et al.
    Bhakat, Priyaranjan
    Jegerschold, Caroline
    Gyobu, Nobuhiko
    Mitsuoka, Kaoru
    Fujiyoshi, Yoshinori
    Morgenstern, Ralf
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Structural basis for detoxification and oxidative stress protection in membranes2006In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 360, no 5, p. 934-945Article in journal (Refereed)
    Abstract [en]

    Synthesis of mediators of fever, pain and inflammation as well as protection against reactive molecules and oxidative stress is a hallmark of the MAPEG superfamily (membrane associated proteins in eicosanoid and glutathione metabolism). The structure of a MAPEG member, rat mictosomal glutathione transferase 1, at 3.2 angstrom resolution, solved here in complex with glutathione by electron crystallography, defines the active site location and a cytosolic domain involved in enzyme activation. The glutathione binding site is found to be different from that of the canonical soluble glutathione transferases. The architecture of the homotrimer supports a catalytic mechanism involving subunit interactions and reveals both cytosolic and membraneous substrate entry sites, providing a rationale for the membrane location of the enzyme.

  • 24.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Biomechanical reconstruction of traumatic brain injuries: Correlation between injury patterns and FE models2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no 1, p. S154-Article in journal (Refereed)
  • 25.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Biomechanics as a forensic science tool: Reconstruction of a traumatic head injury using the finite element method2006In: Scandinavian Journal of Forensic Science, ISSN 1503-9552, no 2, p. 73-78Article in journal (Refereed)
  • 26.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Evaluation of head injury criteria using a finite element model validated against experiments on localized brain motion, intracerebral acceleration, and intracranial pressure2006In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 11, no 1, p. 65-79Article in journal (Refereed)
    Abstract [en]

    The objective of the present study was to analyze the effect of different load directions and durations following impact using a finite element (FE) model of the human head. A detailed FE model of the human head was developed and validated against available cadaver experiment data for three impact directions (frontal, occipital, and lateral). Loads corresponding to the same impact power were imposed in different directions. Furthermore, the head injury criterion (HIC), the recently proposed head impact power (HIP) criterion, as well as peak angular acceleration, and change in angular and translational velocity were evaluated with respect to the strain in the central nervous system (CNS) tissue. A significant correlation was found between experiments and simulations with regard to intracranial pressure data for a short-duration impulse and intracerebral acceleration characteristics for a long-duration impulse with a high-angular component. However, a poor correlation with the simulations was found for the intracranial pressures for the long-duration impulse. This is thought to be a result of air introduced to the intracranial cavity during experimental testing. Smaller relative motion between the brain and skull results from lateral impact than from a frontal or occipital blow for both the experiments and FE simulations. It was found that the influence of impact direction had a substantial effect on the intracranial response. When evaluating the global kinematic injury measures for the rotational pulses, the change in angular velocity corresponded best with the intracranial strains found in the FE model. For the translational impulse, on the other hand, the HIC and the HIP showed the best correlation with the strain levels found in the model.

  • 27.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    The internal membranes of the human head protect the brain during impact2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no 1, p. S639-Article in journal (Refereed)
  • 28.
    Kleiven, Svein
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    On the consequences of head size following impact to the human head - Reply2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no 2, p. 385-387Article in journal (Refereed)
  • 29.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Decision Support for Risk Analysis in Small Enterprises2006In: 3rd International Conference Workingonsafety, 2006Conference paper (Refereed)
  • 30.
    Lindh, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Roos, Emma
    KTH, School of Technology and Health (STH).
    Monitoring of SIP-based communication using signalling information for performance measurements2006Conference paper (Refereed)
    Abstract [en]

    This paper presents a prototype implementation of end-to-end monitoring of performance parameters in SIP-based communication. The approach is to integrate signalling information and measurements of user data traffic. Test measurements illustrate some results that can be obtained per session; packet loss, roundtrip delays and their variation, inter-arrival jitter and throughput.

  • 31.
    Linnarsson, D
    et al.
    Karolinska Institutet.
    Spaak, J
    Karolinska Institutet.
    Sundblad, Patrik
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. Karolinska Institutet.
    Baroreflex impairment during rapid posture changes at rest and exercise after 120 days of bed rest.2006In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 96, no 1, p. 37-45Article in journal (Refereed)
    Abstract [en]

    Orthostatic intolerance is common after space flight and head-down tilt (HDT) bed rest. We hypothesized that HDT-induced impairments of arterial blood pressure (AP) control would be more marked during exercise and that recovery of baroreflex function after very long-term HDT would be delayed. Six subjects were studied before (BDC) during (day 60, D60; D113) and after (recovery day 0, R0; R3; R15) 120 days of HDT. Supine resting subjects were exposed to repeated 1 min passive tilts to upright at 3-min interval. During 50 W steady-state exercise corresponding tilt had a 2-min duration at 4-min interval. The amplitudes of the tilt-induced transient beat-by-beat deviations in AP and rate (HR) were determined during the gravity transients. At rest these deviations did not change over time, but during exercise the total peak-to-nadir range of deviations in systolic AP (SAP) at up-tilt and down-tilt increased to 168+/-16% (mean+/-SEM) of BDC at D113 with no clear recovery upto and including R15. Counter-regulatory HR responses were not increased proportionally and especially not tachycardic responses to up-tilt, resulting in a reduction of baroreflex sensitivity (deltaRR-interval/deltaSAP) by 55+/-9% of BDC at D113 with no recovery upto and including R15. We conclude that prolonged bed rest cause long-lasting impairments in AP control and baroreflex function in exercising humans.

  • 32. Neely, Gregory
    et al.
    Wilhelmson, Emma
    KTH, School of Technology and Health (STH).
    Self-reported incidents, accidents, and use of protective gear among small-scale forestry workers in Sweden2006In: Safety Science, ISSN 0925-7535, E-ISSN 1879-1042, Vol. 44, no 8, p. 723-732Article in journal (Refereed)
    Abstract [en]

    Self-reported data were collected from 156 self-employed small-scale forestry workers regarding their work, including use of safety gear and number and type of incidents and accidents. About 40% of the respondents reported that during the previous 24 months they had some kind of work-related accident where an injury occurred, and/or experienced in incident, a close call that could have resulted in an injury. Of those injured or involved in an accident, 50% reported that at the time of the accident or incident they were not fully using their safety gear. Sixty-seven percent of the accident victims reported seeking medical attention for their injuries. No significant relationships were found between production level, age, use of safety gear or sensation seeking tendencies and the reports of accidents and incidents. Accidents and incidents were most likely to occur during felling, thinning and transportation activities and were usually caused by unforeseen interactions with falling trees/branches or equipment. Compared to earlier surveys of Swedish small-scale forestry workers, consistent use of all required safety gear was down by 10% to 50%. Protective pants and gloves were the items least likely to be used while ear, eye and foot protection were most likely to be used. The results indicate that better planning during felling processes may be the key to reducing the number of accidents for this population.

  • 33. Nilsson, B.
    et al.
    Henningsson, R.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Wandt, B.
    Transesophageal echocardiographic acquisition of mitral annulus motion during monitoring of left ventricular function in anesthetized patients2006In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 19, no 5, p. 499-506Article in journal (Refereed)
    Abstract [en]

    Objective. We investigated the feasibility and reproducibility of transesophageal (TE) recordings of displacements and velocities of 4 sites of the mitral annulus in anesthetized patients. Correlations to transthoracic measures and influence of the respiratory cycle were also investigated. Methods: A total of 24 patients without heart disease were included. Another 10 patients were enrolled for the reproducibility study. Systolic and diastolic velocities and amplitude of motion were extracted from color-coded Doppler tissue recordings. Results: The reproducibility was not acceptable for the anterior site or for late diastolic velocities. Transthoracic values were higher than TE values. A somewhat higher displacement during inspiration in spontaneous respiration and during expiration in positive pressure ventilation was seen. Conclusions: The anterior site should be omitted when TE recordings of the mitral annulus are used. TE values are about 15% lower than transthoracic values. There is no need to take the respiratory cycle into account.

  • 34.
    Nobel, Gerard
    et al.
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Tribukait, Arne
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Kölegård, Roger
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Mekjavic, Igor B.
    Motion sickness increases the risk of accidental hypothermia2006In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 98, no 1, p. 48-55Article in journal (Refereed)
    Abstract [en]

    Motion sickness (MS) has been found to increase body-core cooling during immersion in 28 degrees C degrees C water, an effect ascribed to attenuation of the cold- induced peripheral vasoconstriction (Mekjavic et al. in J Physiol 535(2):619-623, 2001). The present study tested the hypothesis that a more profound cold stimulus would override the MS effect on peripheral vasoconstriction and hence on the core cooling rate. Eleven healthy subjects underwent two separate head-out immersions in 15 degrees C water. In the control trial (CN), subjects were immersed after baseline measurements. In the MS-trial, subjects were rendered motion sick prior to immersion, by using a rotating chair in combination with a regimen of standardized head movements. During immersion in the MS-trial, subjects were exposed to an optokinetic stimulus (rotating drum). At 5-min intervals subjects rated their temperature perception, thermal comfort and MS discomfort. During immersion mean skin temperature, rectal temperature, the difference in temperature between the non-immersed right forearm and 3rd finger of the right hand (Delta T (ff)), oxygen uptake and heart rate were recorded. In the MS-trial, rectal temperature decreased substantially faster (33%, P < 0.01). Also, the Delta T (ff) response, an index of peripheral vasomotor tone, as well as the oxygen uptake, indicative of the shivering response, were significantly attenuated (P < 0.01 and P < 0.001, respectively) by MS. Thus, MS may predispose individuals to hypothermia by enhancing heat loss and attenuating heat production. This might have significant implications for survival in maritime accidents.

  • 35. Peppard, J.
    et al.
    Rylander, Anna
    KTH, School of Technology and Health (STH).
    From Value Chain to Value Network: Insights for Mobile Operators2006In: European Management Journal, ISSN 0263-2373, E-ISSN 1873-5681, Vol. 24, no 2-3, p. 128-141Article in journal (Refereed)
    Abstract [en]

    The concept of a value chain has assumed a dominant position in the strategic analysis of industries. However, the value chain is underpinned by a particular value creating logic and its application results in particular strategic postures. Adopting a network perspective provides an alternative perspective that is more suited to New Economy organisations, particularly for those where both the product and supply and demand chain is digitized. This paper introduces the value network concept and illuminates on its value creating logic. It introduces Network Value Analysis (NVA) as a way to analyse competitive ecosystems. To illustrate its application, the provision of mobile services and content is explored to identify potential strategic implications for mobile operators.

  • 36. Purhonen, P
    et al.
    Thomsen, K
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Maunsbach, AB
    The structure of Na,K-ATPase in native pig kidney membranes2006In: Proceedings of the 16th International Microscopy Congress, 2006Conference paper (Refereed)
  • 37. Purhonen, P.
    et al.
    Thomsen, K.
    Maunsbach, A. B.
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Association of renal Na,K-ATPase alpha-subunit with the beta- and gamma-subunits based on cryoelectron microscopy2006In: Journal of Membrane Biology, ISSN 0022-2631, E-ISSN 1432-1424, Vol. 214, no 3, p. 139-146Article in journal (Refereed)
    Abstract [en]

    Na,K-ATPase transports Na+ and K+ across cell membranes and consists of alpha- and beta-subunits. Na,K-ATPase also associates with small FXYD proteins that regulate the activity of the pump. We have used cryoelectron microscopy of two-dimensional crystals including data to 8 A resolution to determine the three-dimensional (3-D) structure of renal Na,K-ATPase containing FXYD2, the gamma-subunit. A homology model for the a- subunit was calculated from a Ca2+-ATPase structure and used to locate the additional beta- and gamma-subunits present in the 3-D map of Na,K-ATPase. Based on the 3-D map, the beta- subunit is located close to transmembrane helices M8 and M10 and the gamma-subunit is adjacent to helices M2 and M9 of the alpha-subunit.

  • 38. Ressner, M.
    et al.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Jansson, T.
    Hoff, L.
    Ask, P.
    Janerot-Sjoberg, B.
    Effects of ultrasound contrast agents on Doppler tissue velocity estimation2006In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 19, no 2, p. 154-164Article in journal (Refereed)
    Abstract [en]

    The combination of Doppler tissue imaging and myocardial contrast echocardiography has the potential to provide information about motion and perfusion of the myocardium in a single examination. The purpose of this study was to establish how the presence of ultrasound contrast agent (UCA) affects measurements of Doppler tissue velocities in vivo and in vitro. We performed echocardiography in 12 patients with ischemic heart disease before and immediately after a slow intravenous infusion of the UCA Optison, using color Doppler tissue imaging to examine the effect of contrast agents in vivo. The myocardial peak systolic velocities and their integrals were analyzed in digitally stored cineloops before and after contrast administration. To distinguish between methodologic and physiologic factors affecting the measurement of tissue velocity in vitro, experiments with a rotating disk and a flow cone phantom were also carried out for the 3 contrast agents: Optison, Sonovue, and Sonazoid. in vivo results show that the values for peak systolic velocity increased by about 10% during contrast infusion, from mean 5.2 +/- 1.8 to 5.7 +/- 2.3 cm/s (P = .02, 95% confidence interval 2%-16%). The increase in myocardial peak systolic velocities was verified in experimental models in which the UCA increased the estimated mean velocity in the order of 5% to 20% for the motion interval of 5 to 7 cm/s, corresponding to the myocardial velocities studied in vivo. The response was similar for all 3 contrast agents and was not affected by moderate variations in concentration of the agent. We have shown that the presence UCA will affect Doppler tissue measurements in vivo and in vitro. The observed bias is presumed to be an effect of harmonic signal contribution from rupturing contrast agent microbubbles and does not indicate biologic or physiologic effects.

  • 39. Ruan, J. S.
    et al.
    Prasad, P.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    On the consequences of head size following impact to the human head [2] (multiple letters)2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no 2, p. 383-385Article in journal (Refereed)
  • 40. Ruchowska, E.
    et al.
    Plociennik, W. A.
    Zylicz, A.
    Mach, H.
    Kvasil, J.
    Algora, A.
    Amzal, N.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Borge, M. G.
    Boutami, R.
    Butler, P. A.
    Cederkäll, J.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Fogelberg, B.
    Fraile, L. M.
    Fynbo, H. O. U.
    Hagebo, E.
    Hoff, P.
    Gausemel, H.
    Jungclaus, A.
    Kaczarowski, R.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kurcewicz, W.
    Lagergren, K.
    KTH, School of Engineering Sciences (SCI), Physics.
    Nacher, E.
    Rubio, B.
    Syntfeld, A.
    Tengblad, O.
    Wasilewski, A. A.
    Weissman, L.
    Nuclear structure of Th-2292006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 4Article in journal (Refereed)
    Abstract [en]

    Lifetimes of excited states in Th-229, populated in the beta decay of Ac-229, have been measured using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new gamma lines have been introduced into the beta-decay scheme of Ac-229 based on results of gamma gamma coincidence measurements. Reduced transition probabilities have been determined for more than 70 gamma transitions in Th-229. Average parallel to D-0 parallel to values of 0.029(1), 0.077(3), and 0.024(5) e fm have been deduced for the lowest K-pi=1/2(+/-),3/2(+/-), and 5/2(+/-) parity partner bands, respectively. Excited states in Th-229 and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5-eV, 3/2(+) isomeric state is predicted to be about 10 h. Potential energy surfaces on the (beta(2),beta(3)) plane for the lowest single quasiparticle configurations in Th-229 have been calculated using the Strutinsky method.

  • 41. Schagerlof, Ulrika
    et al.
    Wilson, Greer
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Al-Karadaghi, Salam
    Hagerhall, Cecilia
    Transmembrane topology of FRO2, a ferric chelate reductase from Arabidopsis thaliana2006In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 62, no 02-jan, p. 215-221Article in journal (Refereed)
    Abstract [en]

    Iron uptake in Arabidopsis thaliana is mediated by ferric chelate reductase FRO2, a transmembrane protein belonging to the flavocytochrome b family. There is no high resolution structural information available for any member of this family. We have determined the transmembrane topology of FRO2 experimentally using the alkaline phosphatase fusion method. The resulting topology is different from that obtained by theoretical predictions and contains 8 transmembrane helices, 4 of which build up the highly conserved core of the protein. This core is present in the entire flavocytochrome b family. The large water soluble domain of FRO2, which contains NADPH, FAD and oxidoreductase sequence motifs, was located on the inside of the membrane.

  • 42. Scotti, S.
    et al.
    Mauri, M.
    Barbieri, R.
    Jawad, Bassam
    KTH, School of Technology and Health (STH), Medical Engineering.
    Cerutti, S.
    Mainardi, L.
    Brown, E. N.
    Villamira, M. A.
    Automatic quantitative evaluation of emotions in E-learning applications2006In: Annu Int Conf IEEE Eng Med Biol Proc, 2006, p. 1359-1362Conference paper (Refereed)
    Abstract [en]

    The long term goal of our research is to develop a tool for recognizing human emotions during e-learning processes. This could be accomplished by combining quantitative indexes extracted from non-invasive recordings of four physiological signals: namely skin conductance, blood volume pulse, electrocardiogram and electroencephalogram. Wearable, non-invasive sensors, communicating with a PC, were applied to 30 students and data were collected during exposure to three different computer-mediated content stimuli designed to evoke specific emotional states: stress, relaxation and engagement. In this paper we describe both the general emotion evaluation algorithm, and present a preliminary results suggesting that some of the quantitative indexes may be successful in characterizing and distinguishing between the three different emotional states.

  • 43.
    Seoane, Fernando
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701).
    Bragós, Ramon
    Technical University of Catalonia.
    Lindecrantz, Kaj
    Current Source for Wideband Electrical Bioimpedance Spectroscopy Based on a Single Operational Amplifier2006In: WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING 2006, VOL 14, PTS 1-6 / [ed] Kim, SI; Suh, TS, 2006, p. 707-710Conference paper (Refereed)
    Abstract [en]

    Traditionally, measurements of electrical bioimpedance for medical diagnostic purposes have used only low frequencies, usually below 100 kHz. The analysis focused only on the resistive part of the impedance; very often at low frequencies the reactive part of the impedance is negligible. Recent studies of the electrical bioimpedance spectrum, both real and imaginary parts, have indicated new potential applications e.g. detection of meningitis, skin cancer assessment and brain cellular edema detection. An important functional unit in a wideband impedance spectrometer is the current source used to inject the current into the tissue under study. A current source must provide an output current virtually constant over the frequency range of interest and independent of the load at the output. Several designs have been proposed over the years but the performance of them all degraded markedly near bellow 1 MHz e.g. Ackmann in 1993, Bragos et al in 1994 and Bertemes-Filho et al in 2000. The development of electronic technology has made available devices that allow us to obtain a current source with large output impedance, larger than 100 k Omega, above I MHz and based in a simple single Op-Amp circuit topology. Simulation results and experimental measurements are compared and the most important parameters of the VCCS are analytically studied and experimentally tested, including the dependency to changes in the circuit elements and the incidence of the Op-Amp parameters on the current source features.

  • 44.
    Shams, S
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Langaas, S.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology.
    Jacks, G.
    Ahmed, KM.
    Thunqvist, Eva-Lotta
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Chen, D.
    Granlund, A.
    Mapping and interpretation of field data for evaluation and mitigation of groundwater arsenic contamination in Bangladesh2006In: Journal of Hydroinformatics, ISSN 1464-7141, E-ISSN 1465-1734, Vol. 8, no 1, p. 25-36Article in journal (Refereed)
    Abstract [en]

    Problems of arsenic contamination have been reported from a large number of aquifers in various parts of the world. Especially in Bangladesh, the presence of arsenic in groundwater has been the major environmental health catastrophe that has affected the source of safe water not only for drinking but also for irrigation purposes. The unavailability and inaccessibility of data and dissemination of proper and rapid information has further reduced the accessibility to safe drinking water for nearly 95% of the population of the country. The development of solutions for the arsenic problem and the allocation of resources for mitigation are information-oriented activities. This paper focuses on the mapping and interpretation of field data (based on a case study area) through the application of GIS for presenting and assessing the scope of the arsenic problem in Bangladesh. The mapping and interpretation is done taking into consideration the geophysical characteristics, socio-economic conditions and socio-cultural behavior of the people living in the study area. The mapping and interpretation technique is aimed at assisting lanners and policy makers at the district level to make an assessment about the extent and magnitude of the arsenic problem based on an estimation of the exposed population and the extent and severity of groundwater contamination. In addition, it will enable decision-makers to select possible options and give recommendations based on users’ responses. The advantages of this interpretation technique are that the knowledge base is easy to build and any updated information or modifications can be quickly incorporated into the knowledge base.

  • 45. Simpson, N. E.
    et al.
    Grant, S. C.
    Gustavsson, Lenita
    KTH.
    Peltonen, Vilje-Mia
    KTH, School of Technology and Health (STH), Medical Engineering.
    Blackband, S. J.
    Constantinidis, I.
    Biochemical consequences of alginate encapsulation: A NMR study of insulin-secreting cells2006In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 27, no 12, p. 2577-2586Article in journal (Refereed)
    Abstract [en]

    In this study we explore the biochemical consequences of alginate encapsulation on beta TC3 cells. C-13 NMR spectroscopy and isotopomer analysis were used to investigate the effects of encapsulation on several enzymatic processes associated with the TCA cycle. Our data show statistically significant differences in various enzymatic fluxes related to the TCA cycle and insulin secretion between monolayer and algainate-encapsulated cultures. The principal cause for these effects was the process of trypsinization. Embedding the trypsinized cells in alginate beads did not have a compounded effect on the enzymatic fluxes of entrapped cells. However, an additional small but statistically significant decrease in insulin secretion was measured in encapsulated cells. Finally, differences in either enzymatic fluxes or Qlucose consumption as a function of bead diameter were not observed. However, differences in T-2, assessed by H-1 NMR microimaging, were observed as a function of bead diameter, suggesting that smaller beads became more organized with time in culture, while larger beads displayed a looser organization.

  • 46.
    Valastyán, Iván
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Molnar, J.
    Novak, D.
    Vegh, J.
    Emri, M.
    Tron, L.
    A SPECT demonstrator - revival of a gamma camera2006In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 563, no 1, p. 274-277Article in journal (Refereed)
    Abstract [en]

    A gamma camera has been updated and converted to serve as a demonstrator for educational purposes. The gantry and the camera head were the only part of the system that remained untouched. The main reason for this modernization was to increase the transparency of the gamma camera by partitioning the different logical building blocks of the system and thus providing access for inspection and improvements throughout the chain. New data acquisition and reconstruction software has been installed. By taking these measures, the camera is now used in education and also serves as a platform for tests of new hardware and software solutions. The camera is also used to demonstrate 3D (SPECT) imaging by collecting 2D projections from a rotatable cylindrical phantom. Since the camera head is not attached mechanically to the phantom, the effect of misalignment between the head and the rotation axis of the phantom can be studied. (c) 2006 Elsevier B.V. All rights reserved.

  • 47. Wandt, B.
    et al.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lundback, S.
    Misinterpretation about the contribution of the left ventricular long-axis shortening to the stroke volume2006In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 291, no 5, p. H2550-H2550Article in journal (Refereed)
  • 48.
    Zika-Wiktorsson, Annika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sundström, Per
    KTH, School of Technology and Health (STH).
    Engwall, Mats
    VINNOVA, Swedish Governmental Agency for Innovation Systems.
    Project Overload: An Exploratory Study of Work and Management in Multi-Project Settings2006In: International Journal of Project Management, ISSN 0263-7863, E-ISSN 1873-4634, Vol. 24, no 5, p. 385-394Article in journal (Refereed)
    Abstract [en]

    This study investigates psychosocial aspects of work in multi-project settings and how project members and project managers at operational level perceive their work situation. Work in a multi-project setting entails a complicated situation characterized by tight schedules, multi-tasking, increased coordination expenditures, and a large amount of set-up time when alternating between tasks. The study addresses the issue of project overload, a construct that in this study reflects perceived fragmentation, disruption and inefficiency, caused by switching between assignments for separate but simultaneous projects. An explorative approach was adopted for the study, and new models were created and investigated. The primary source of data was a web-based questionnaire. The questionnaire was administered to project co-workers (n = 392) in nine companies in Sweden (response rate: 81%). The companies represented manufacturing, pharmaceutical and construction industries, and all occupied a leading position on their respective markets. The results show that almost one-third of the respondents were under perceived project overload, and that 21% (p ≤ .001) of the variance on this variable could be explained by four factors. In order of magnitude, these factors were: (1) lack of opportunities for recuperation, (2) inadequate routines, (3) scarce time resources, and (4) a large number of simultaneous projects. Further, the study indicated that there are associations between high level of project overload and (a) high levels of psychological stress reactions, (b) decreased competence development, and (c) deviations from time schedules.

  • 49.
    Zou, Hong
    et al.
    Department of Mechanical Engineering, The Ohio State University.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Schmiedeler, James P.
    Department of Mechanical Engineering, The Ohio State University.
    The Effect of Brain Mass and Moment of Inertia on Relative Brain-Skull Displacement in Low-Severity Impacts2006Conference paper (Refereed)
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