| 1. |
- Alkner, Björn, 1968-, et al.
(författare)
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Muscle Activation During Gravity-Independent Resistance Exercise Compared to Common Exercises
- 2019
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Ingår i: Aerospace Medicine and Human Performance. - : AEROSPACE MEDICAL ASSOC. - 2375-6314 .- 2375-6322. ; 90:6, s. 506-512
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The aim was to study quadriceps muscle activation during resistance exercise using a flywheel device, developed as a gravity-independent resistance exercise device to be used during spaceflight, compared with traditional strength training exercises. METHODS: Eight healthy men experienced in resistance exercise performed the following exercises in random order: flywheel leg press (FW), knee extension isokinetic dynamometry (ID), barbell front squat (FS), weight stack leg press (LP), and weight stack knee extension (KE). They accomplished eight repetitions of coupled concentric and eccentric actions with simultaneous recordings of surface electromyography (EMG) from the three superficial quadriceps muscles and knee angles using electrogoniometry. Maximal voluntary contraction (MVC) in knee extension was performed before and after these measurements. RESULTS: EMG averaged across muscles and angles and normalized to MVC was 99/76% in FW, 48/41% FS, 65/47% LP, 81/52% KE, and 93/84% ID in concentric/eccentric phases, respectively. FW and ID showed higher mean EMG activity than LP and FS concentrically and higher than all other exercises eccentrically. No difference in activity between FW and ID was found. Pre- and post-MVC torque was comparable. DISCUSSION: Quadriceps muscle activation was superior in FW and ID exercises compared to the other exercises. The difference was most pronounced in the eccentric phase, but even concentric activation was lower in traditional closed chain exercises. This data supports that FW is an effective training tool and should be considered when designing strength training programs for spaceflights and on Earth.
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| 2. |
- Berglund, Lars, 1955-
(författare)
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Measurement Variability Related to Insulin Secretion and Sensitivity : Assessment and Implications in Epidemiological Studies
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a growing interest in random measurement variability of biological variables. In regression models, such variability of the predictors yields biased estimators of coefficients (regression dilution bias). The objectives of this thesis were to develop an efficient method to correct for such bias, to reveal the relative importance of insulin sensitivity and insulin secretion, corrected for regression dilution bias, on glucose tolerance, and to explore the seasonal nature of the variability of insulin sensitivity.A reliability study is often designed to randomly select subjects from the main study. Our idea was to collect replicates for subjects with extreme values on their first measurement. The extreme selection design, in combination with maximum likelihood estimation, resulted in an efficient estimator of a corrected regression coefficient in a simple linear regression model. Results were presented theoretically and with an application: The relation between insulin sensitivity and fasting insulin in Uppsala Longitudinal Study of Adult Men (ULSAM) where the extreme selection design decreased the standard error of the estimated regression coefficient with 28 per cent compared with the random sampling design.We estimated the partial longitudinal effects of the predictors insulin sensitivity and insulin secretion, corrected for regression dilution bias, on glucose tolerance in ULSAM. The effects of the predictors, when corrected, were similar.Insulin sensitivity in ULSAM increased during summer and decreased during winter and insulin secretion exposed opposite variation keeping glucose homeostasis nearly constant. Insulin sensitivity was related to outdoor temperature.In summary, we developed a cost-efficient reliability design for correction for regression dilution bias. Insulin sensitivity and insulin secretion had similar longitudinal effects on glucose tolerance, which implies that interventions aimed at these targets are equally important. Further, we revealed the seasonal nature of variations of insulin sensitivity and insulin secretion. This result has implications on glycaemic control in diabetic patients.
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| 3. |
- Carbone, Dina, et al.
(författare)
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Design and performance of a dedicated coherent X-ray scanning diffraction instrument at beamline NanoMAX of MAX IV
- 2022
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Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 29, s. 876-887
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Tidskriftsartikel (refereegranskat)abstract
- The diffraction endstation of the NanoMAX beamline is designed to provide high-flux coherent X-ray nano-beams for experiments requiring many degrees of freedom for sample and detector. The endstation is equipped with high-efficiency Kirkpatrick-Baez mirror focusing optics and a two-circle goniometer supporting a positioning and scanning device, designed to carry a compact sample environment. A robot is used as a detector arm. The endstation, in continued development, has been in user operation since summer 2017.
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| 4. |
- Forsberg, Fredrik, et al.
(författare)
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CMOS-integrated Si/SiGe quantum-well infrared microbolometer focal plane arrays manufactured with very large-scale heterogeneous 3-d integration
- 2015
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers Inc.. - 0792-1233 .- 1077-260X .- 1558-4542. ; 21:4
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate infrared focal plane arrays utilizing monocrystalline silicon/silicon-germanium (Si/SiGe) quantum-well microbolometers that are heterogeneously integrated on top of CMOS-based electronic read-out integrated circuit substrates. The microbolometers are designed to detect light in the long wavelength infrared (LWIR) range from 8 to 14 μm and are arranged in focal plane arrays consisting of 384 × 288 microbolometer pixels with a pixel pitch of 25 μm × 25 μm. Focal plane arrays with two different microbolometer designs have been implemented. The first is a conventional single-layer microbolometer design and the second is an umbrella design in which the microbolometer legs are placed underneath the microbolometer membrane to achieve an improved pixel fill-factor. The infrared focal plane arrays are vacuum packaged using a CMOS compatible wafer bonding and sealing process. The demonstrated heterogeneous 3-D integration and packaging processes are implemented at wafer-level and enable independent optimization of the CMOS-based integrated circuits and the microbolometer materials. All manufacturing is done using standard semiconductor and MEMS processes, thus offering a generic approach for integrating CMOS-electronics with complex miniaturized transducer elements
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| 5. |
- Forsberg, Fredrik, et al.
(författare)
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Very large scale heterogeneous integration (VLSHI) and wafer-level vacuum packaging for infrared bolometer focal plane arrays
- 2013
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Ingår i: Infrared physics & technology. - : Elsevier BV. - 1350-4495 .- 1879-0275. ; 60, s. 251-259
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Tidskriftsartikel (refereegranskat)abstract
- Imaging in the long wavelength infrared (LWIR) range from 8 to 14 μm is an extremely useful tool for non-contact measurement and imaging of temperature in many industrial, automotive and security applications. However, the cost of the infrared (IR) imaging components has to be significantly reduced to make IR imaging a viable technology for many cost-sensitive applications. This paper demonstrates new and improved fabrication and packaging technologies for next-generation IR imaging detectors based on uncooled IR bolometer focal plane arrays. The proposed technologies include very large scale heterogeneous integration for combining high-performance, SiGe quantum-well bolometers with electronic integrated read-out circuits and CMOS compatible wafer-level vacuum packing. The fabrication and characterization of bolometers with a pitch of 25 μm × 25 μm that are arranged on read-out-wafers in arrays with 320 × 240 pixels are presented. The bolometers contain a multi-layer quantum well SiGe thermistor with a temperature coefficient of resistance of -3.0%/K. The proposed CMOS compatible wafer-level vacuum packaging technology uses Cu-Sn solid-liquid interdiffusion (SLID) bonding. The presented technologies are suitable for implementation in cost-efficient fabless business models with the potential to bring about the cost reduction needed to enable low-cost IR imaging products for industrial, security and automotive applications.
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| 6. |
- Johansson, Ulf, et al.
(författare)
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NanoMAX : the hard X-ray nanoprobe beamline at the MAX IV Laboratory
- 2021
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Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 28, s. 1935-1947
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Tidskriftsartikel (refereegranskat)abstract
- NanoMAX is the first hard X-ray nanoprobe beamline at the MAX IV laboratory. It utilizes the unique properties of the world's first operational multi-bend achromat storage ring to provide an intense and coherent focused beam for experiments with several methods. In this paper we present the beamline optics design in detail, show the performance figures, and give an overview of the surrounding infrastructure and the operational diffraction endstation.
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| 7. |
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