| 1. |
- Evander, Mikael, et al.
(författare)
-
Acoustic trapping of cells in a microfluidic format
- 2005
-
Ingår i: Proceedings of µTAS 2005 Conference. ; 1, s. 515-517
-
Konferensbidrag (refereegranskat)abstract
- This paper presents, for the first time, non-contact acoustic trapping of cells in a microfluidic format. The employed acoustic force maintains the cells in the center of a fluidic channel while allowing for perfusion of e.g. nutrients or drugs as well as optical monitoring of the cells. Neural stem cells have been acoustically trapped and tested for viability after 15 minutes of ultrasonic radiation. It is also shown that it is possible to grow yeast cells suspended in an acoustic standing wave while perfusing with cell media.
|
|
| 2. |
- Johansson, Jonny, et al.
(författare)
-
Project: EISCAT 3D
- 2007
-
Annan publikation (populärvet., debatt m.m.)
|
|
| 3. |
- Johansson, Linda, et al.
(författare)
-
Temperature evaluation of soft and hard PZT transducers for ultrasonic
- 2005
-
Ingår i: Proceedings of µTAS 2005 Conference. ; 2, s. 1428-1430
-
Konferensbidrag (refereegranskat)abstract
- This paper reports a comparison of soft and hard piezoceramic transducer materials used for ultrasonic particle trapping in a microfluidic bioanalytical platform. The investigation is made with the objective to obtain high acoustic forces with a minimum of temperature increase. Themperature is a critical parameter for bioassays and most often need to be kept below a certain level to allow handling of e.g. temperature sensitive proteins. The main conclusion in this paper is that it is possible to get efficieint trapping with a temperature increase of only a few degrees using a hard type III transducer material.
|
|
| 4. |
- Carlson, R. F., et al.
(författare)
-
A method for measuring light ion reaction cross-sections
- 2005
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 547:2-3, s. 541-554
-
Tidskriftsartikel (refereegranskat)abstract
- An experimental procedure for measuring reaction cross-sections of light ions in the energy range 20 50 MeV/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross-sections for five different sizes of the solid angle in steps from 99.1% to 99.8% of the total solid angle. The final reaction cross-section values are obtained by extrapolation to the full solid angle.
|
|
| 5. |
|
|
| 6. |
- Forsberg, Anders, et al.
(författare)
-
Landmark-Based Software for Anatomical Measurements : A Precision Study
- 2009
-
Ingår i: Clinical anatomy (New York, N.Y. Print). - : Wiley. - 0897-3806 .- 1098-2353. ; 22:4, s. 456-462
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop a software program, called Landmarker, which would aid studies of complex anatomical morphometry by simplifying the manual identification of landmarks in 3D images. We also tested its precision on routine magnetic resonance imaging (MRI) scans. To understand human biological variation, there is a need to identify morphological characteristics from the exterior and the interior of human anatomy. MRI, as opposed to other radiographic methods (mainly based on X-ray techniques), supplies good soft tissue contrast, which allows for more complex assessments than what bony landmarks can provide. Because automation of this assessment is highly demanding, one of the primary goals for the new software was to enable more rapid identification of landmark sets in 3D image data. Repeat acquisition of head MRIs having a resolution of 0.94 x 0.94 x 1.20 mm3 were performed on 10 volunteers. Intra- and interoperator, as well as interacquisition variations of manual identification of exterior, craniofacial interior, and brain landmarks were studied. The average distances between landmarks were <1.8 mm, <2.3 mm, and <2.0 mm in the intra- and interoperator, and interacquisition evaluations, respectively. This study presents new software for time efficient identification of complex craniofacial landmarks in 3D MRI. To the best of our knowledge, no evaluation of software for rapid landmark-based analysis of complex anatomies from 3D MR data has yet been presented. This software may also be useful for studies in other anatomical regions and for other types of image data.
|
|
| 7. |
|
|
| 8. |
- Heard-Costa, Nancy L, et al.
(författare)
-
NRXN3 is a novel locus for waist circumference : a genome-wide association study from the CHARGE Consortium
- 2009
-
Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 5:6, s. e1000539-
-
Tidskriftsartikel (refereegranskat)abstract
- Central abdominal fat is a strong risk factor for diabetes and cardiovascular disease. To identify common variants influencing central abdominal fat, we conducted a two-stage genome-wide association analysis for waist circumference (WC). In total, three loci reached genome-wide significance. In stage 1, 31,373 individuals of Caucasian descent from eight cohort studies confirmed the role of FTO and MC4R and identified one novel locus associated with WC in the neurexin 3 gene [NRXN3 (rs10146997, p = 6.4×10−7)]. The association with NRXN3 was confirmed in stage 2 by combining stage 1 results with those from 38,641 participants in the GIANT consortium (p = 0.009 in GIANT only, p = 5.3×10−8 for combined analysis, n = 70,014). Mean WC increase per copy of the G allele was 0.0498 z-score units (0.65 cm). This SNP was also associated with body mass index (BMI) [p = 7.4×10−6, 0.024 z-score units (0.10 kg/m2) per copy of the G allele] and the risk of obesity (odds ratio 1.13, 95% CI 1.07–1.19; p = 3.2×10−5 per copy of the G allele). The NRXN3 gene has been previously implicated in addiction and reward behavior, lending further evidence that common forms of obesity may be a central nervous system-mediated disorder. Our findings establish that common variants in NRXN3 are associated with WC, BMI, and obesity.
|
|
| 9. |
- Hedlund, Joel, et al.
(författare)
-
BRICHOS - a superfamily of multidomain proteins with diverse functions.
- 2009
-
Ingår i: BMC research notes. - : Springer Science and Business Media LLC. - 1756-0500. ; 2, s. 180-
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: The BRICHOS domain has been found in 8 protein families with a wide range of functions and a variety of disease associations, such as respiratory distress syndrome, dementia and cancer. The domain itself is thought to have a chaperone function, and indeed three of the families are associated with amyloid formation, but its structure and many of its functional properties are still unknown. FINDINGS: The proteins in the BRICHOS superfamily have four regions with distinct properties. We have analysed the BRICHOS proteins focusing on sequence conservation, amino acid residue properties, native disorder and secondary structure predictions. Residue conservation shows large variations between the regions, and the spread of residue conservation between different families can vary greatly within the regions. The secondary structure predictions for the BRICHOS proteins show remarkable coherence even where sequence conservation is low, and there seems to be little native disorder. CONCLUSIONS: The greatly variant rates of conservation indicates different functional constraints among the regions and among the families. We present three previously unknown BRICHOS families; group A, which may be ancestral to the ITM2 families; group B, which is a close relative to the gastrokine families, and group C, which appears to be a truly novel, disjoint BRICHOS family. The C-terminal region of group C has nearly identical sequences in all species ranging from fish to man and is seemingly unique to this family, indicating critical functional or structural properties.
|
|
| 10. |
- Johansson, Joel
(författare)
-
A flexible design automation system for toolsets for the rotary draw bending of aluminium tubes
- 2007
-
Ingår i: 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. - 0791838064
-
Konferensbidrag (refereegranskat)abstract
- For parts suppliers in the manufacturing industry, the process of preliminary production preparation and the subsequent calculation of offers are critical business activities. A vital part of production preparation is the design of fixtures and tooling necessary for many processes of metal forming. In order for a company to give quick responses to customer enquiries or changes in prior specifications, it would be highly beneficial with a degree of automation in this design process. This implies the development of a computer based system able to capture existing design procedures and associated knowledge for the classes of tooling required for the forming process. In this work, an implementation for the rotary draw bending of aluminum tubing has been done to exemplify how to develop an automated design system. The system is based on heuristic knowledge developed over many years of practical experience, knowledge analytically derived from fundamental theory found in scientific literature, and rules based on empirical data from trial manufacturing. The system applies knowledge to a given specification that a skilled engineer otherwise would do manually. The system output can be used to evaluate whether a tube is producible. The main idea behind the system is to use knowledge objects containing information on inputs, outputs, constraints and what software are used to implement the knowledge pieces. This approach makes the system highly flexible and allows for multiple types of knowledge that might overlap. When an offering calculation is wanted, the system is set to run applicable knowledge objects for presented input data. Other objects are run when an accurate calculation for detailing is wanted for a more detailed set of input data. The system is built on readily available commercial software packages connected with a simple Visual Basic .Net program. When building a system of this kind, it is essential that the knowledge documentation and structure be such that the functions of the system can be easily understood by the users of the system and by future developers. Aspects of user friendliness, transparency and scalability are addressed in the summary of this paper.
|
|
| 11. |
- Johansson, Joel, et al.
(författare)
-
Automated design of rotary draw bending tools : an approach based on generic CAD-models driven by heuristic and algorithmic knowledge
- 2006
-
Ingår i: International conference on efficient development of manufacturing machines and processes, 2006, Wroclaw, Poland. ; 6:3, s. 86-96
-
Konferensbidrag (refereegranskat)abstract
- For parts suppliers in the manufacturing industry the process of preliminary production preparation and subsequent calculation of offers are critical business activities. A vital part of production preparation is the design of fixtures and tooling necessary for many processes of metal forming. For a company to give quick responses to customer enquiries, or changes in prior specifications, it would be highly beneficial with a degree of automation in this design process. This implies the development of a computer based system able to capture existing design procedures and associated knowledge for the classes of tooling required for the forming process. In this work we exemplify an automated design system for tooling by an implementation for rotary draw bending of aluminium tubing. The system is based on established design practice and heuristic knowledge developed over many years of practical experience. The system will evaluate whether a given specification is producible with existing materials and equipment, select suitable machine, determine process parameters and determine type and dimensions of components of form die, clamp die, follower or pressure die, wiper and mandrel. The system is built on readily available commercial software packages. When building a system of this kind it is essential that the knowledge documentation and structure is such that the functions of the system can be easily understood by the users of the system and by future developers. Aspects of user friendliness, transparency and scalability are addressed in the summary of this paper.
|
|
| 12. |
- Johansson, Joel, 1978-
(författare)
-
Automated Manufacturability Analysis of the Draw Bending of Complex Aluminum Profiles
- 2009
-
Ingår i: ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IDETC/CIE 2009).
-
Konferensbidrag (refereegranskat)abstract
- Manufacturing companies are required to develop and produce products that meet increased requirements from customers and investors on shortened time spans. One key factor in meeting these requirements is the efficiency of the product development and the production preparation process. Design automation is a powerful tool to increase efficiency in these two processes. The benefits of automating the production preparation process are shortened lead-time, improved product performance, and ultimately decreased cost. Further, automation is beneficial as it increases the ability to adapt products to new product specifications with production preparations done in few or in a single step. During the automation process, knowledge about the production preparation process is collected and stored in the corporation systems, thus allowing full control over the design of production equipments. The contribution of this work is a method for connecting knowledge pieces implemented in auxiliary software applications using an inference engine. The knowledge pieces can control CAD-models and automatically generate, execute, and interpret finite element analyses. The presented method allows the automation of corporation know-how developed by skilled engineers over time. Further, it is possible for the resulting systems to meet criteria for good design automation systems such as low effort of developing, low level of investment, user readable and understandable knowledge, scalability, and flexibility. The method is exemplified by an implementation for analyzing manufacturability of the rotary draw bending of extruded sections of aluminum where the sections are complex. The output from the example system is based on established design practice and heuristic knowledge developed over many years of practical experience, rules analytically derived from fundamental physical laws, and finite element calculations. The system applies knowledge to a given specification that a skilled engineer otherwise would do manually. The method is described along with the example system in this paper.
|
|
| 13. |
- Johansson, Joel, 1978-
(författare)
-
Automatic Producibility Analysis of the Draw Bending of Aluminium Tubes with Several Bends
- 2009
-
Ingår i: NAFEMS World Congress 2009. - Glasgow : NAFEMS Ltd. - 9781874376422
-
Konferensbidrag (refereegranskat)abstract
- Increased pressure on manufacturing companies to develop and produce products that meet tightened requirements from customers and investors on shortened time spans require increased efficiency of the product development and the production preparation. Design automation is a powerful tool to increase the efficiency in these two processes. The benefits of automating the production preparation process are shortened led-time, improved product performance, and ultimately decreased cost. Further, automation is beneficial as it increases the ability to adapt products to new product specifications with production preparations done in few or in a single step. During the automation process, knowledge about the production preparation process is collected and stored in company systems, thus allowing full control over the design of production equipments. Finite element analyses (FEA) are often used to test product properties virtually. The process of setting up FEA is many times manual and not strictly formalized; the assumptions made in those calculations highly depend on the analysts’ former experiences and gut feeling. Sometimes there exist parametric FEA-models, but they are hard to interpret for others than the developers. It is beneficial to formalize and automate the process of developing such calculations in order to automate the production preparation of mature and variant-rich products where estimations and validations using FEA are demanded in the whole or parts of the design space. Automating the FEA-process for selected production methods makes the dedicated FEA-models more flexible and more transparent. It also makes them live longer and be more available for engineers that are not FEA-specialists. The FEA-specialists will have more time to solve general problems rather than focusing on instances of the product. This work deal with the automation of FEA-based producibility analysis of aluminium tubes with several bends, as is a part of the production preparation of many products. The method proposed includes the usage of a KBE-system that handles knowledge objects that connect to auxiliary software applications. This is done in order to generate a design synthesis based on product specifications, to develop a geometrical model of the synthesis in a CAD-system, to generate mesh parts in a CAD-system, to set up and run a FEM-calculation based on the generated mesh, and finally to extract required results from the calculation result files. The complete process of bending the tubes several times is automatically synthesised and analysed.
|
|
| 14. |
- Johansson, Joel, 1978-
(författare)
-
Design Automation Systems for Production Preparation : Applied on the Rotary Draw Bending Process
- 2008
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Intensive competition on the global market puts great pressure on manufacturing companies to develop and produce products that meet requirements from customers and investors. One key factor in meeting these requirements is the efficiency of the product development and the production preparation process. Design automation is a powerful tool to increase efficiency in these two processes. The benefits of automating the production preparation process are shortened led-time, improved product performance, and ultimately decreased cost. Further, automation is beneficial as it increases the ability to adapt products to new product specifications with production preparations done in few or in a single step. During the automation process, knowledge about the production preparation process is collected and stored in central systems, thus allowing full control over the design of production equipments. Three main topics are addressed in this thesis: the flexibility of design automation systems, knowledge bases containing conflicting rules, and the automation of the finite element analysis process. These three topics are discussed in connection with the production preparation process of rotary draw bending. One conclusion drawn from the research is that it is possible to apply the concept of design automation to the production preparation process at different levels of automation depending on characteristics of the implemented knowledge. In order to make design automation systems as flexible as possible, the concept of object orientation should be adapted when building the knowledge base and when building the products geometrical representations. It is possible to automate the process of setting up, running, and interpreting finite element analyses to a great extent and making the automated finite element analysis process a part of the global design automation system.
|
|
| 15. |
- Johansson, Joel, 1978
(författare)
-
Design Automation Systems for Production Preparation
- 2008
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Intensive competition on the global market puts great pressure on manufacturing companies to develop and produce products that meet requirements from customers and investors. One key factor in meeting these requirements is the efficiency of the product development and the production preparation process. Design automation is a powerful tool to increase efficiency in these two processes.The benefits of automating the production preparation process are shortened led-time, improved product performance, and ultimately decreased cost. Further, utomation is beneficial as it increases the ability to adapt products to new product specifications with production preparations done in few or in a single step. During the automation process, knowledge about the production preparation process is collected and stored in central systems, thus allowing full control over the design of production equipments.Three main topics are addressed in this thesis: the flexibility of design automation systems, knowledge bases containing conflicting rules, and the automation of the finite element analysis process. These three topics are discussed in connection with the production preparation process of rotary draw bending.One conclusion drawn from the research is that it is possible to apply the concept of design automation to the production preparation process at different levels of automation depending on characteristics of the implemented knowledge. In order to make design automation systems as flexible as possible, the concept of object orientation should be adapted when building the knowledge base and when building the products geometrical representations. It is possible to automate the process of setting up, running, andinterpreting finite element analyses to a great extent and making the automated finite element analysis process a part of the global design automation system.Keywords: Design automation, Rotary draw bending, Knowledge Based Engineering (KBE), and Finite Element Analysis (FEA).
|
|
| 16. |
|
|
| 17. |
- Johansson, Joel, 1978
(författare)
-
Manufacturability Analysis Using Integrated KBE, CAD and FEM
- 2008
-
Ingår i: 2008 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference: 13th Design for Manufacturing and the Life Cycle Conference (DFMLC).
-
Konferensbidrag (refereegranskat)abstract
- Finite element analyses (FEA) are often used to test product properties virtually. The process of setting up FEA is many times manual and not strictly formalized; the assumptions made in those calculations highly depend on the analysts’ former experiences and gut feeling. Sometimes there exist parametric FEA-models, but they are hard to interpret for others than the developers. These parametric FEA-models are also highly inflexible. It is beneficial to formalize and automate the process of developing such calculations in order to automate the product development process for mature and variant-rich products where predictions and validations using FEA are demanded in the whole or parts of the design space. Making the automated FEA-models more flexible and more transparent makes them live longer and be more available for engineers that are not FEA-specialists. The FEA-specialists will have more time to solve general problems rather than focusing on instances of the product. In this paper, a proposal is made on how to integrate Knowledge Based Engineering (KBE), CAD and FEM to make the automation of FEA flexible, transparent, and easy to use. The method proposed includes the usage of an inference engine that handles knowledge objects that connect to auxiliary software applications. In the paper, an implementation example is presented where toolsets for the rotary draw bending of aluminium tubing are analyzed for manufacturability.
|
|
| 18. |
- Johansson, Joel
(författare)
-
Undersökning av antikroppar riktade mot Mo- MLVs fusionsprotein Env i IAS (Isomerization Arrested Stage) form
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Retrovirus invaderar nya celler genom membranfusion, en process som drivs av membranproteinet Env (Envelope). Env är det enda virala proteinet på virusutsidan och därför en potentiell angreppspunkt för neutraliserande antikroppar. Genom att aktivera Env proteinet hos Mo-MLV (Moloney murine leukemia virus) i närvaro av en alkylator blockeras isomerisering av en disulfid-bindning mellan proteinets två subenheter SU och TM. Alkyleringen låser env i en intermediär form som kallas IAS (isomerisation arrested state). För att undersöka om Env i IAS form är ett lämpligt antigen för produktion av neutraliserande antikroppar har vi immuniserat balb/c-möss med denna renade IAS-Env-trimerer och etablerat antikroppsproducerande hybridom från mjältceller från utvalda möss. Antikroppar i musserum och medium från hybridomkulturer undersöktes med immunfällning, ELISA, och XC cell-cell fusion. En preliminär karaktärisering av antikroppar från tre hybridomkolonier visar viss hämning av XC cell-cellfusion, d.v.s. neutraliserande verkan in vitro
|
|
| 19. |
- Johansson, Lars, et al.
(författare)
-
Lipid Mobilization Following Roux-en-Y Gastric Bypass Examined by Magnetic Resonance Imaging and Spectroscopy
- 2008
-
Ingår i: Obesity Surgery. - : Springer Science and Business Media LLC. - 0960-8923 .- 1708-0428. ; 18:10, s. 1297-1304
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent developments of magnetic resonance imaging (MRI) and spectroscopy have made it possible to quantify lipid deposited in different tissues. To what extent an improvement of glucose tolerance shortly after Roux-en-Y gastric bypass surgery (RYGBP) is reflected in lipid levels in liver and skeletal muscle, markers of insulin resistance, has not been clarified. METHODS: Whole-body MRI and MR spectroscopy (MRS) of liver and muscle and measurements of biochemical markers of glucose and lipid metabolism were performed at baseline and 1, 6, and 12 months following surgery in seven morbidly obese women. Volumes of adipose tissue depots and liver and muscle lipids were assessed from the MRI/MRS data. RESULTS: At 1 month postoperatively, body mass index and visceral and subcutaneous adipose tissues were reduced by 9%, 26%, and 10%, respectively, whereas no reductions in intrahepatocellular or skeletal intramyocellular lipid concentrations were found. Free fatty acid and beta-hydroxybutyrate levels were elevated two- and sixfold, respectively; glucose and insulin levels were lowered, indicating increased insulin sensitivity. Further weight loss up to 1 year was associated with reductions in all investigated lipid depots investigated, with the exception of the intramyocellular compartment. CONCLUSION: RYGBP causes rapid lipid mobilization from visceral and subcutaneous adipose depots and enhanced free fatty acid flux to the liver. An exceptional disconnection between liver fat and insulin sensitivity occurs in the early dynamic phase after surgery. However, in the late phase, the energy restriction imposed by the surgical procedure also reduces the liver lipids, but not the intramyocellular lipids.
|
|
| 20. |
- Johansson, Malin E V, 1971, et al.
(författare)
-
The inner of the two Muc2 mucin-dependent mucus layers in colon is devoid of bacteria.
- 2008
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 105:39, s. 15064-9
-
Tidskriftsartikel (refereegranskat)abstract
- We normally live in symbiosis with approximately 10(13) bacteria present in the colon. Among the several mechanisms maintaining the bacteria/host balance, there is limited understanding of the structure, function, and properties of intestinal mucus. We now demonstrate that the mouse colonic mucus consists of two layers extending 150 mum above the epithelial cells. Proteomics revealed that both of these layers have similar protein composition, with the large gel-forming mucin Muc2 as the major structural component. The inner layer is densely packed, firmly attached to the epithelium, and devoid of bacteria. In contrast, the outer layer is movable, has an expanded volume due to proteolytic cleavages of the Muc2 mucin, and is colonized by bacteria. Muc2(-/-) mice have bacteria in direct contact with the epithelial cells and far down in the crypts, explaining the inflammation and cancer development observed in these animals. These findings show that the Muc2 mucin can build a mucus barrier that separates bacteria from the colon epithelia and suggest that defects in this mucus can cause colon inflammation.
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Kullberg, Joel, et al.
(författare)
-
Automated Assessment of Whole-Body Adipose Tissue Depots From Continuously Moving Bed MRI : A Feasibility Study
- 2009
-
Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 30:1, s. 185-193
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To present an automated algorithm for segmentation of visceral, subcutaneous, and total volumes of adipose tissue depots (VAT, SAT, TAT) from whole-body MRI data sets and to investigate the VAT segmentation accuracy and the reproducibility of all depot assessments. MATERIALS AND METHODS: Repeated measurements were performed on 24 volunteer subjects using a 1.5 Tesla clinical MRI scanner and a three-dimensional (3D) multi-gradient-echo sequence (resolution: 2.1 x 2.1 x 8 mm(3), acquisition time: 5 min 15 s). Fat and water images were reconstructed, and fully automated segmentation was performed. Manual segmentation of the VAT reference was performed by an experienced operator. RESULTS: Strong correlation (R = 0.999) was found between the automated and manual VAT assessments. The automated results underestimated VAT with 4.7 +/- 4.4%. The accuracy was 88 +/- 4.5% and 7.6 +/- 5.7% for true positive and false positive fractions, respectively. Coefficients of variation from the repeated measurements were: 2.32 % +/- 2.61%, 2.25% +/- 2.10%, and 1.01% +/- 0.74% for VAT, SAT, and TAT, respectively. CONCLUSION: Automated and manual VAT results correlated strongly. The assessments of all depots were highly reproducible. The acquisition and postprocessing techniques presented are likely useful in obesity related studies.
|
|
| 24. |
- Kullberg, Joel, et al.
(författare)
-
Practical approach for estimation of subcutaneous and visceral adipose tissue
- 2007
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 27:3, s. 148-153
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: The first objective was to investigate the correlations between anthropometrical measurements and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in two cohorts differing in age using magnetic resonance imaging (MRI) as reference. A second objective was to investigate the potential usage of abdominal diameters in practical estimation of adipose tissue compartments using these cohorts. Methods: Measurements of body mass index, waist circumference, sagittal abdominal diameter (sagittal AD) and transverse abdominal diameter (transverse AD) were obtained from 336 volunteers of age 14-70 years. Manual measurements of VAT and SAT from single slice MRI at the L4-L5 level were used as reference. The abdominal diameters were measured from the MR images. Linear correlations between the anthropometrical measurements and the reference were studied. Results: Sagittal AD showed the strongest correlation to VAT (r > 0·780, P<0·0001) and transverse AD was found to give information about the amount of SAT (r > 0·866, P<0·0001). The ellipse spanned by the sagittal AD and the transverse AD was strongly correlated to the total amount of adipose tissue (r ≥ 0·962 P<0·0001). Conclusion: Strong correlations were found between sagittal and transverse abdominal diameters, assessed using MRI, and VAT and SAT, respectively. These results suggest the use of abdominal diameters in practical estimations of VAT and SAT depots.
|
|
| 25. |
- Kullberg, Joel, et al.
(författare)
-
Reproducibility of hepatic triglyceride content assessment in normals using localized magnetic resonance spectroscopy
- 2009
-
Ingår i: Diabetes, obesity and metabolism. - : Wiley. - 1462-8902 .- 1463-1326. ; 11:5, s. 516-518
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: To investigate the reproducibility of measurements of hepatic triglyceride content (HTGC) in subjects with normal HTGC using localized (1)H-magnetic resonance spectroscopy ((1)H-MRS) and a clinical 1.5T scanner. METHODS: The (1)H-MRS acquisition was performed with a common protocol using the whole-body coil and no respiratory triggering. An upper limit of normal HTGC of 5.56% was used. Duplicate measurements, including subject repositioning, were acquired from 23 subjects, 19 of whom had a normal HTGC. RESULTS: The mean coefficient of variation (CV) from the duplicate measurements was 14.8% (20.5% before exclusion of a subject who was considered to be an outlier). Mean CVs of subgroups below and above the 1% HTGC limit were 19.8 and 7.0 respectively. CONCLUSIONS: The mean CV calculated in subjects with HTGC in the normal range was found to be higher than CVs of wide range HTGC groups reported in the literature. It is concluded that the reproducibility of HTGC measurements using (1)H-MRS depends on the HTGC range. These findings are of importance in reproducibility studies and in estimations of required study group sizes.
|
|
| 26. |
- Kullberg, Joel, et al.
(författare)
-
Whole-body adipose tissue analysis: comparison of MRI, CT and dual energy X-ray absorptiometry.
- 2009
-
Ingår i: The British journal of radiology. - : British Institute of Radiology. - 1748-880X .- 0007-1285. ; 82:974, s. 123-30
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to validate a recently proposed MRI-based T(1)-mapping method for analysis of whole-body adipose tissue (AT) using an established CT protocol as reference and to include results from dual energy X-ray absorptiometry (DEXA). 10 subjects, drawn from the Swedish Obese Subjects Sibling-pairs study, were examined using CT, MRI and DEXA. The CT analysis was based on 28 imaged slices. T(1) maps were calculated using contiguous MRI data from two different gradient echo sequences acquired using different flip angles. CT and MRI comparison was performed slice-wise and for the whole-body region. Fat weights were compared between all three modalities. Strong correlations (r > or = 0.977, p<0.0001) were found between MRI and CT whole-body and AT volumes. MRI visceral AT volume was underestimated by 0.79 +/- 0.75 l (p = 0.005), but total AT was not significantly different from that estimated by CT (MRI - CT = -0.61+/-1.17 l; p = 0.114). DEXA underestimated fat weights by 5.23 +/- 1.71 kg (p = 0.005) compared with CT. MRI underestimated whole-body volume by 2.03 +/- 1.61 l (p = 0.005) compared with CT. Weights estimated either by CT or by DEXA were not significantly different from weights measured using scales. In conclusion, strong correlations were found between whole-body AT results from CT, MRI-based T(1) mapping and DEXA. If the differences between the results from T(1)-mapping and CT-based analysis are accepted, the T(1)-mapping method allows fully automated post-processing of whole-body MRI data, allowing longitudinal whole-body studies that are also applicable for children and adolescents.
|
|
| 27. |
|
|
| 28. |
- Ostensvik, Tove, et al.
(författare)
-
Work exposure and complaints in a sample of French and Norwegian forest machine operators. A comparative field study within the ErgoWood programme.
- 2005
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present work is to evaluate muscle activity pattern, psychosocial working conditions and self-reported complaints of fatigue and pain in the neck, shoulders and forearms in two samples of forest machine operators driving harvesters in France and Norway. The EMG readings from four muscle groups were analysed in predetermined periods of sustained low level muscle activity (SULMA), ranging from 1.2-5 seconds up to > 20 minutes. The main result was the similarity between operators of the two different countries. Tendencies were found for higher static muscle activity and less muscular relaxation in all evaluated muscles in the French operators, but significant only for the right trapezius muscle. However, the level of muscular complaints was significantly higher among the Norwegian operators. The amount of both short and long SULMA was not significantly higher in the Norwegian group for the right side. This indicates that the amount of low-level muscle activity could be of higher importance than the gaps, or that the gaps are too short to have effect in reducing risk for discomfort or pain. The results indicate that the introduction of the SULMA concept may be of importance as a method for MSD risk assessment. Future work should concentrate on exploring the best linkage between SULMA and muscular complaints.
|
|
| 29. |
- Phillipson, Mia, et al.
(författare)
-
The gastric mucus layers: constituents and regulation of accumulation.
- 2008
-
Ingår i: American journal of physiology. Gastrointestinal and liver physiology. - : American Physiological Society. - 0193-1857 .- 1522-1547. ; 295:4
-
Tidskriftsartikel (refereegranskat)abstract
- The mucus layer continuously covering the gastric mucosa consists of a loosely adherent layer that can be easily removed by suction, leaving a firmly adherent mucus layer attached to the epithelium. These two layers exhibit different gastroprotective roles; therefore, individual regulation of thickness and mucin composition were studied. Mucus thickness was measured in vivo with micropipettes in anesthetized mice [isoflurane; C57BL/6, Muc1-/-, inducible nitric oxide synthase (iNOS)-/-, and neuronal NOS (nNOS)-/-] and rats (inactin) after surgical exposure of the gastric mucosa. The two mucus layers covering the gastric mucosa were differently regulated. Luminal administration of PGE(2) increased the thickness of both layers, whereas luminal NO stimulated only firmly adherent mucus accumulation. A new gastroprotective role for iNOS was indicated since iNOS-deficient mice had thinner firmly adherent mucus layers and a lower mucus accumulation rate, whereas nNOS did not appear to be involved in mucus secretion. Downregulation of gastric mucus accumulation was observed in Muc1-/- mice. Both the firmly and loosely adherent mucus layers consisted of Muc5ac mucins. In conclusion, this study showed that, even though both the two mucus layers covering the gastric mucosa consist of Muc5ac, they are differently regulated by luminal PGE(2) and NO. A new gastroprotective role for iNOS was indicated since iNOS-/- mice had a thinner firmly adherent mucus layer. In addition, a regulatory role of Muc1 was demonstrated since downregulation of gastric mucus accumulation was observed in Muc1-/- mice.
|
|
| 30. |
- Tutkun, Murat, 1977, et al.
(författare)
-
Highly Time- and Space-Resolved Experiment on a High Reynolds Number Turbulent Boundary Layer
- 2007
-
Ingår i: ADVANCES IN TURBULENCE XI, Proceedings of the 11th EUROMECH European Turbulence Conference, June 25-28, 2007, Porto, Portugal, Editors: J.M.L.M. Palma and A.Silva Lopes Springer Proceedings in Physics 117, Springer, Heidelberg. - 9783540726036 ; , s. 346-348
-
Konferensbidrag (refereegranskat)
|
|
