| 1. |
- Akiba, K., et al.
(författare)
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The LHCb VELO Upgrade module construction
- 2024
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 19:6
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Tidskriftsartikel (refereegranskat)abstract
- The LHCb detector has undergone a major upgrade for LHC Run 3. This Upgrade I detector facilitates operation at higher luminosity and utilises full-detector information at the LHC collision rate, critically including the use of vertex information. A new vertex locator system, the VELO Upgrade, has been constructed. The core element of the new VELO are the double-sided pixelated hybrid silicon detector modules which operate in vacuum close to the LHC beam in a high radiation environment. The construction and quality assurance tests of these modules are described in this paper. The modules incorporate 200 mu m thick, n -on -p silicon sensors bump-bonded to 130 nm technology ASICs. These are attached with high precision to a silicon microchannel substrate that uses evaporative CO 2 cooling. The ASICs are controlled and read out with flexible printed circuits that are glued to the substrate and wire -bonded to the chips. The mechanical support of the module is given by a carbon fibre plate, two carbon fibre rods and an aluminium plate. The sensor attachment was achieved with an average precision of 21 mu m, more than 99.5% of all pixels are fully functional, and a thermal figure of merit of 3 Kcm 2 W - 1 was achieved. The production of the modules was successfully completed in 2021, with the final assembly and installation completed in time for data taking in 2022.
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| 2. |
- Akiba, K., et al.
(författare)
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Measurement of thermal properties of the LHCb VELO detector using track-based software alignment
- 2023
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Ingår i: Journal of Instrumentation. - : Institute of Physics (IOP). - 1748-0221. ; 18:10
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Tidskriftsartikel (refereegranskat)abstract
- The thermal properties of the LHCb Vertex Locator (VELO) are studied using the real-time detector alignment procedure. The variation of the position and orientation of the detector elements as a function of the operating temperature of the VELO is presented. This study uses a dataset collected by the LHCb experiment during a VELO temperature scan performed at the end of LHC Run 2 (October 2018). Significant shrinkage of the VELO modules is observed at the operating temperature of -30(degrees)C compared to the laboratory measurements on a single module taken at a range of temperatures from +45(degrees)C to -25(degrees)C. The thermal shrinkage expected from the extrapolation of laboratory measurements to lower temperatures, and the results of this alignment study are in good agreement.
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| 3. |
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| 4. |
- Gjelstad, I. M. F., et al.
(författare)
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Expression of perilipins in human skeletal muscle in vitro and in vivo in relation to diet, exercise and energy balance
- 2012
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Ingår i: Archives of Physiology and Biochemistry. - : Informa UK Limited. - 1381-3455 .- 1744-4160. ; 118:1, s. 22-30
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Tidskriftsartikel (refereegranskat)abstract
- The perilipin proteins enclose intracellular lipid droplets. We describe the mRNA expression of the five perilipins in human skeletal muscle in relation to fatty acid supply, exercise and energy balance. We observed that all perilipins were expressed in skeletal muscle biopsies with the highest mRNA levels of perilipin 2, 4 and 5. Cultured myotubes predominantly expressed perilipin 2 and 3. In vitro, incubation of myotubes with fatty acids enhanced mRNA expression of perilipin 1, 2 and 4. In vivo, low fat diet increased mRNA levels of perilipin 3 and 4. Endurance training, but not strength training, enhanced the expression of perilipin 2 and 3. Perilipin 1 mRNA correlated positively with body fat mass, whereas none of the perilipins were associated with insulin sensitivity. In conclusion, all perilipins mRNAs were expressed in human skeletal muscle. Diet as well as endurance exercise modulated the expression of perilipins.
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| 5. |
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| 6. |
- Sarneel, Judith M., et al.
(författare)
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Reading tea leaves worldwide : decoupled drivers of initial litter decomposition mass-loss rate and stabilization
- 2024
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Ingår i: Ecology Letters. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 27:5
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Tidskriftsartikel (refereegranskat)abstract
- The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
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| 7. |
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| 8. |
- Jans, A., et al.
(författare)
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Impact of dietary fat quantity and quality on skeletal muscle fatty acid metabolism in subjects with the metabolic syndrome
- 2012
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Ingår i: Metabolism. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 61:11, s. 1554-1565
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Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance is characterized by disturbances in lipid metabolism in skeletal muscle. Our aim was to investigate whether gene expression and fatty acid (FA) profile of skeletal muscle lipids are affected by diets differing in fat quantity and quality in subjects with the metabolic syndrome (MetS) and varying degrees of insulin sensitivity. 84 subjects (age 57.3 ± 0.9 y, BMI 30.9 ± 0.4 kg/m 2, 42 M/42 F) were randomly assigned to one of four iso-energetic diets: high-SFA (HSFA); high-MUFA (HMUFA) or two low-fat, high-complex carbohydrate diets, supplemented with 1.24 g/day of long-chain n-3 PUFA (LFHCCn-3) or control oil (LFHCC) for 12 weeks. In a subgroup of men (n = 26), muscle TAG, DAG, FFA and phospholipid contents were determined including their fractional synthetic rate (FSR) and FA composition at fasting and 4 h after consumption of a high-fat mixed-meal, both pre- and post-intervention. Genes involved in lipogenesis were downregulated after HMUFA (mean fold change - 1.3) and after LFHCCn-3 (fold change - 1.7) in insulin resistant subjects (< median of (S I)), whereas in insulin sensitive subjects (> median of insulin sensitivity) the opposite effect was shown (fold change + 1.6 for both diets). HMUFA diet tended to decrease FSR in TAG (P =.055) and DAG (P =.066), whereas the LFHCCn-3 diet reduced TAG content (P =.032). In conclusion, HMUFA and LFHCCn-3 diets reduced the expression of the lipogenic genes in skeletal muscle of insulin resistant subjects, whilst HMUFA reduced the fractional synthesis rate of DAG and TAG and LFHCC n-3 the TAG content. Our data indicate that these diets may reduce muscle fat accumulation by affecting the balance between FA synthesis, storage and oxidation.
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| 9. |
- Pekkinen, M., et al.
(författare)
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Osteoporosis and skeletal dysplasia caused by pathogenic variants in SGMS2
- 2019
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Ingår i: Jci Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 4:7
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Tidskriftsartikel (refereegranskat)abstract
- Mechanisms leading to osteoporosis are incompletely understood. Genetic disorders with skeletal fragility provide insight into metabolic pathways contributing to bone strength. We evaluated 6 families with rare skeletal phenotypes and osteoporosis by next-generation sequencing. In all the families, we identified a heterozygous variant in SGMS2, a gene prominently expressed in cortical bone and encoding the plasma membrane-resident sphingomyelin synthase SMS2. Four unrelated families shared the same nonsense variant, c.148C>T (p.Arg50*), whereas the other families had a missense variant, c.185T>G (p.IIe62Ser) or c.191T>G (p.Met64Arg). Subjects with p.Arg50* presented with childhood-onset osteoporosis with or without cranial sclerosis. Patients with p.IIe62Ser or p.Met64Arg had a more severe presentation, with neonatal fractures, severe short stature, and spondylometaphyseal dysplasial Several subjects had experienced peripheral facial nerve palsy or other neurological manifestations. Bone biopsies showed markedly altered bone material characteristics, including defective bone mineralization. Osteoclast formation and function in vitro was normal. While the p.Arg50* mutation yielded a catalytically inactive enzyme, p.IIe62Ser and p.Met64Arg each enhanced the rate of de novo sphingomyelin production by blocking export of a functional enzyme from the endoplasmic reticulum. SGMS2 pathogenic variants underlie a spectrum of skeletal conditions, ranging from isolated osteoporosis to complex skeletal dysplasia, suggesting a critical role for plasma membrane-bound sphingomyelin metabolism in skeletal homeostasis.
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| 10. |
- Vanderschueren, Dirk, et al.
(författare)
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Active Vitamin D (1,25-Dihydroxyvitamin D) and Bone Health in Middle-Aged and Elderly Men: The European Male Aging Study (EMAS).
- 2013
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 98:3, s. 995-1005
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Tidskriftsartikel (refereegranskat)abstract
- Context:There is little information on the potential impact of serum 1,25-dihydroxyvitamin D [1,25(OH)(2)D] on bone health including turnover.Objective:The objective of the study was to determine the influence of 1,25(OH)(2)D and 25-hydroxyvitamin D [25(OH)D] on bone health in middle-aged and older European men.Design, Setting, and Participants:Men aged 40-79 years were recruited from population registers in 8 European centers. Subjects completed questionnaires that included questions concerning lifestyle and were invited to attend for quantitative ultrasound (QUS) of the heel, assessment of height and weight, and a fasting blood sample from which 1,25(OH)(2)D, 25(OH)D, and PTH were measured. 1,25(OH)(2)D was measured using liquid chromatography tandem mass spectrometry. Bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (β-cTX) were also measured. Dual-energy x-ray absorptiometry (DXA) of the hip and lumbar spine was performed in 2 centers.Main Outcome Measure(s):QUS of the heel, bone markers P1NP and β-cTX, and DXA of the hip and lumbar spine were measured.Results:A total of 2783 men, mean age 60.0 years (SD 11.0) were included in the analysis. After adjustment for age and center, 1,25(OH)(2)D was positively associated with 25(OH)D but not with PTH. 25(OH)D was negatively associated with PTH. After adjustment for age, center, height, weight, lifestyle factors, and season, 1,25(OH)(2)D was associated negatively with QUS and DXA parameters and associated positively with β-cTX. 1,25(OH)(2)D was not correlated with P1NP. 25(OH)D was positively associated with the QUS and DXA parameters but not related to either bone turnover marker. Subjects with both high 1,25(OH)(2)D (upper tertile) and low 25(OH)D (lower tertile) had the lowest QUS and DXA parameters and the highest β-cTX levels.Conclusions:Serum 1,25(OH)(2)D is associated with higher bone turnover and poorer bone health despite being positively related to 25(OH)D. A combination of high 1,25(OH)(2)D and low 25(OH)D is associated with the poorest bone health.
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