| 1. |
- Trajceska, L., et al.
(författare)
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Skin af and food, is there any relation?
- 2011
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Ingår i: International Journal of Artificial Organs. - 0391-3988 .- 1724-6040. ; 34:8, s. 606-606
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Hawke, Emma, 1975-
(författare)
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Training-induced increase in mitochondrial biogenesis
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endurance training leads to an improved ability of muscle to utilize oxygen. This is related to an increased density and function of mitochondria. The biogenesis and adaptation of mitochondria is a complex process mediated by various signalling pathways and seems to be highly sensitive to the type of exercise and the local environment in the muscle. Changes in the muslce environment in terms of altered metabolism and substrate accumulation are affected by changes in acid/base balance in response to exercise. Recent studies have shown that changes in acid/base balance may affect the regulation of mitochondrial adaptation to acute exercise; however, how this responds to training and relates to performance adaptations in humans is unclear. Similarly, the effect of acid/base balance on molecular mechanisms underlying mitochondrial biogenesis is unclear. The objectives of this thesis were to examine the relationship between acid/base balance, mitochondrial biogenesis and adaptation and explore the mechanisms which regulate mitochondrial adaptation. To realize these aims a series of related investigations were undertaken. Initially, cultured L6 myotubes were used to assess perturbations of the signaling pathways involved in mitochondrial biogenesis, as a result of alterations in acid/base balance, alone and in combination with lactate. The combined effects of elevated lactate and lowered pH resulted in greater activation of signaling pathways than the effects of altering either lactate or pH alone. These results support previous findings that propose lactate as an important initiator of signaling cascades for the transcription of genes involved in mitochondrial biogenesis. Further, they also indicate that exercise-induced production of lactate and lowering of pH may be important activators of cell signaling involved in muscle adaptation. In a second study, the effects of artificially lowered pH on pre- and post-exercise expression of regulators and downstream target genes involved in mitochondrial biogenesis were assessed. Participants performed high-intensity interval exercise on two separate occasions, following the ingestion of either ammonium chloride or placebo the day before and on the day of the exercise trial in a randomised, counterbalanced order. The mRNA content of PGC-1α, citrate synthase (CS), cytochrome c (CYT-C), hexokinase II (HKII)and glucose transporter 4 (GLUT4) were determined in biopsies taken from the vastus lateralis muscle before, immediately after exercise and during recovery. Results indicated that acidosis increases the expression of PGC-1α and downstream target genes involved in mitochondrial biogenesis at rest, but suppresses the normal increased gene response following high-intensity exercise. These findings indicate that lowered pH may interfere with exercise-induced mitochondrial biogenesis. Finally an intensive training study was conducted to determine whether impeding exercise-induced acidosis during training alters adaptations in mitochondrial function and performance. Another group of participants undertook a six-week periodised high-intensity interval training programme, a protocol known to produce increases in mitochondrial biogenesis. Participants were matched for aerobic fitness and randomly assigned to one of two different training groups. One group ingested sodium bicarbonate and the other group ingested a placebo prior to each training session. Performance tests, blood and muscle biopsies were collected before and after the six week training period and assessed for changes in aerobic fitness, blood metabolites and muscle markers of mitochondrial function and biogenesis. Both training groups showed substantial changes in performance and physiological measures following the training period, however, suppressing exercise-induced acidosis during training did not significantly improve mitochondrial adaptations or performance in comparison to the placebo condition. However, there was a large degree of individual variation in the response and there were trends towards greater adaptations when exercise-induced acidosis was attenuated. The findings from these series of studies show that signaling cascades are influenced by alterations in acid/base balance, alone and in combination with lactate. Skeletal muscle cell-signalling and gene expression networks are extremely complex with multiple points of regulation and signal divergence. Although at this stage the exact mechanism by which acid/base balance plays a role in altering the signaling mechanisms which regulate mitochondrial function, biogenesis and muscle adaptation are unclear, these studies show that the interaction of altered hydrogen ion concentration and substrate accumulation and utilisation plays an important role in mitochondrial adaptation to training.
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| 3. |
- Wang, Faming, et al.
(författare)
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Body-mapping nano-porous polyethylene (PE) clothing could prompt radiative body heat dissipation in moderate warm indoor environments
- 2017
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Ingår i: The 17th International Conference on Environmental Ergonomics. - : International Society for Environmental Ergonomics.
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Konferensbidrag (refereegranskat)abstract
- Extreme weather events like heatwaves and cold spells are increasing due to global warming and human-caused climate change. In hot climates and heatwave incidents, there is a huge amount of energy consumption due to indoor temperature regulation. It has been criticized that the use of air conditioning systems causes too much energy consumption due to the conditioning of large building spaces. Scientists started to seek for effective and energy-saving methods to provide people thermal comfort environments with minimal energy consumptions. One of the effective and most-often methods is the use of personal conditioning clothing such as air ventilation clothing, moisture evaporation clothing and water/air cooling clothing. Nevertheless, such person conditioning clothing still requires cooling sources and energy use. In indoor environments, the infrared radiative heat released by our human body accounts for over 50% of the total body heat. Traditional clothing made from either natural or synthetic fibres is not designed for infrared radiation management because they do prevent the infrared radiative heat from being dissipated to the indoor environment. Therefore, it would be ideal to develop novel passive personal cooling clothing without energy input for indoor occupants. In this study, we have explored the possibility of designing passive personal cooling clothing without energy input. A novel body-mapping nanoporous polyethylene uniform was developed to examine its effectiveness in dissipating infrared radiative heat loss in indoor environments. Eight female subjects voluntarily participated in this study. Each subject completed two 65- minute trials presented in a randomized order. The environmental temperature inside the climate chamber is controlled and increased in 12 equal steps from 24.0 °C to 30.0 °C (i.e., the increment rate is 0.5 °C every five minutes). Heart rate, skin temperatures at 10 local body sites and perceptual sensations such as thermal sensation, thermal preference, thermal acceptability, comfort sensation, skin humidity sensation are surveyed throughout the whole trials. Two clothing ensembles with the same design were chosen: Nanoporous PE clothing and traditional clothing (business trousers and long-sleeve shirt). It was found that the mean skin temperature started to rise at 26.0 °C when wearing cotton clothing while the mean skin temperature increased at around 27.0 °C in nano PE clothing. The post-trial mean skin temperature was increased by 1.29 and 0.92 °C in cotton clothing and nano-porous PE clothing, respectively. It was thus to conclude that the nano-porous PE clothing could prompt radiative body heat dissipation in moderate warm indoor environments and thereby contribute to saving energy.
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| 4. |
- Fulda, S., et al.
(författare)
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Chemosensitivity of solid tumor cells in vitro is related to activation of the CD95 system
- 1998
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Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 76:1, s. 105-114
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Tidskriftsartikel (refereegranskat)abstract
- We have identified the CD95 system as a key mediator of chemotherapy-induced apoptosis in leukemia and neuroblastoma cells. Here, we report that sensitivity of various solid tumor cell lines for drug-induced cell death corresponds to activation of the CD95 system, Upon drug treatment, strong induction of CD95 ligand (CD95-L) and caspase activity were found in chemosensitive tumor cells (Hodgkin, Ewing's sarcoma, colon carcinoma and small cell lung carcinoma) but not in tumor cells which responded poorly to drug treatment (breast carcinoma and renal cell carcinoma). Blockade of CD95 using F(ab')(2) anti-CD95 antibody fragments markedly reduced drug-induced apoptosis, suggesting that drug-triggered apoptosis depended on CD95-L/receptor interaction. Moreover, drug treatment induced CD95 expression, thereby increasing sensitivity for CD95-induced apoptosis, Drug-induced apoptosis critically depended on activation of caspases (ICE/Ced-3-like proteases) since the broad-spectrum inhibitor of caspases zVAD-fmk strongly reduced drug-mediated apoptosis, The prototype substrate of caspases, poly(ADP-ribose) polymerase, was cleaved upon drug treatment, suggesting that CD95-L triggered autocrine/paracrine death via activation of caspases, Our data suggest that chemosensitivity of solid tumor cells depends on intact apoptosis pathways involving activation of the CD95 system and processing of caspases. Our findings may have important implications for new treatment approaches to increase sensitivity and to overcome resistance of solid tumors. (C) 1998 Wiley-Liss, Inc.
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| 5. |
- Gaiotti, Marco, et al.
(författare)
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ISSC 2025 Committee III.1 - Compressive test of a transversely stiffened thin-plated structure with expected early nonlinear response prior to the ultimate capacity. Preliminary comparison of the numerical results
- 2024
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Ingår i: Proceedings of The ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2024). ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- The maritime industry is increasingly utilizing high-strength steels for lightweight ship design. While enhanced yield strength is advantageous, these steels retain the same Young's modulus as lower strength steel grades posing challenges in designing slender structures, particularly concerning structural buckling strength. In longitudinal stiffened ship structures, transverse buckling effects, though less significant than longitudinal stresses, can be difficult to predict. Addressing this, the regulatory framework for verifying the buckling of transversely stiffened panels for ships is a topic of substantial international discussion. A research project supported by Fincantieri led the University of Genova to develop a test configuration assessing a slender ship structure's response to transverse loads. The ISSC 2022-2025 Committee III.1 Ultimate Strength is utilizing this test configuration to conduct a numerical benchmark in three phases, with each phase gradually revealing additional experimental data to the study participants. The benchmark aims to predict the entire end-shortening curve as well as ultimate load to understand load redistribution and quantify energy absorption for dynamic events. This paper presents the preliminary results from Phase 1, focusing on diverse modeling strategies impacting outcomes, including element type, mesh size, and interpretation of initial geometric imperfections among participants in the benchmark study.
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| 6. |
- Barbeito, Ignacio, et al.
(författare)
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Regional climate moderately influences species-mixing effect on tree growth-climate relationships and drought resistance for beech and pine across Europe
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 520
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Tidskriftsartikel (refereegranskat)abstract
- Increasing species diversity is considered a promising strategy to mitigate the negative impacts of global change on forests. However, the interactions between regional climate conditions and species-mixing effects on climate-growth relationships and drought resistance remain poorly documented.In this study, we investigated the patterns of species-mixing effects over a large gradient of environmental conditions throughout Europe for European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.), two species with contrasted ecological traits. We hypothesized that across large geographical scales, the difference of climate-growth relationships and drought resistance between pure and mixed stands would be dependent on regional climate. We used tree ring chronologies derived from 1143 beech and 1164 pine trees sampled in 30 study sites, each composed of one mixed stand of beech and pine and of the two corresponding pure stands located in similar site conditions. For each site and stand, we used Bootstrapped Correlation Coefficients (BCCs) on standardized chronologies and growth reduction during drought years on raw chronologies to analyze the difference in climate-tree growth relationships and resistance to drought between pure and mixed stands.We found consistent large-scale spatial patterns of climate-growth relationships. Those patterns were similar for both species. With the exception of the driest climates where pure and mixed beech stands tended to display differences in growth correlation with the main climatic drivers, the mixing effects on the BCCs were highly variable, resulting in the lack of a coherent response to mixing. No consistent species-mixing effect on drought resistance was found within and across climate zones. On average, mixing had no significant effect on drought resistance for neither species, yet it increased pine resistance in sites with higher climatic water balance in autumn. Also, beech and pine most often differed in the timing of their drought response within similar sites, irrespective of the regional climate, which might increase the temporal stability of growth in mixed compared to pure stands.Our results showed that the impact of species mixing on tree response to climate did not strongly differ between groups of sites with distinct climate characteristics and climate-growth relationships, indicating the interacting influences of species identity, stand characteristics, drought events characteristics as well as local site conditions.
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| 7. |
- Barbeito, Ignacio
(författare)
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Single-image photogrammetry for deriving tree architectural traits in mature forest stands: a comparison with terrestrial laser scanning
- 2019
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Ingår i: Annals of Forest Science. - : Springer Science and Business Media LLC. - 1286-4560 .- 1297-966X. ; 76
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Tidskriftsartikel (refereegranskat)abstract
- Key messageWe compared two methods for detailed individual tree measurements: single image photogrammetry (SIP), a simplified, low-cost method, and the state-of-the-art terrestrial laser scanning (TLS). Our results provide evidence that SIP can be successfully applied to obtain accurate tree architectural traits in mature forests.ContextTree crown variables are necessary in forest modelling; however, they are time consuming to measure directly, and they are measured in many different ways. We compare two methods to obtain crown variables: laser-based and image-based. TLS is an advanced technology for three-dimensional data acquisition; SIP is a simplified, low-cost method.AimsTo elucidate differences between the methods, and validate SIP accuracy and usefulness for forest research, we investigated if (1) SIP and TLS measurements are in agreement in terms of the most widely used tree characteristics; (2) differences between the SIP traits and their TLS counterparts are constant throughout tree density and species composition; (3) tree architectural traits obtained with SIP explain differences in laser-based crown projection area (CPA), under different forest densities and stand compositions; and (4) CPA modelled with SIP variables is more accurate than CPA obtained with stem diameter-based allometric models. We also examined the correspondence between local tree densities extracted from images and from field measurements.MethodsWe compared TLS and SIP in a temperate pure sessile oak and mixed with Scots pine stands, in the Orleans Forest, France. Standard major axis regression was used to establish relations between laser-based and image-based tree height and diameter at breast height. Four SIP-derived traits were compared between the levels of stand density and species composition with a t test, in terms of deviations and biases to their TLS counterparts. We created a set of linear and linear mixed models (LMMs) of CPA(TLS), with SIP variables. Both laser-based and image-based stem diameters were used to estimate CPA with the published allometric equations; the results were then compared with the best predictive LMM, in terms of similarity with CPA(TLS) measurement. Local tree density extracted from images was compared with field measurements in terms of basic statistics and correlation.ResultsTree height and diameter at breast height were reliably represented by SIP (Pearson correlation coefficients r=0.92 and 0.97, respectively). SIP measurements were affected by the stand composition factor; tree height attained higher mean absolute deviation (1.09m) in mixed stands, compared to TLS, than in pure stands (0.66m); crown width was more negatively biased in mixed stands (-0.79m), than in pure stands (-0.05m); and diameter at breast height and crown asymmetry were found unaffected. Crown width and mean branch angle were key SIP explanatory variables to predict CPA(TLS). The model was approximately 2-fold more accurate than the CPA allometric estimations with both laser-based and image-based stem diameters. SIP-derived local tree density was similar to the field-measured density in terms of mean and standard deviation (9.6 (3.5) and 9.4 (3.6) trees per plot, respectively); the correlation between both density measures was significantly positive (r=0.76).ConclusionSIP-derived variables, such as crown width, mean branch angle, branch thickness, and crown asymmetry, were useful to explain tree architectural differences under different densities and stand compositions and may be implemented in many forest research applications. SIP may also provide a coarse measure of local competition, in terms of number of neighbouring trees. Our study provides the first test in mature forest stands, for SIP compared with TLS.
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| 8. |
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| 9. |
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| 10. |
- Kobiałka, Dawid, 1985-
(författare)
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An archaeology of Skyfall
- 2013
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Annan publikation (populärvet., debatt m.m.)abstract
- Archaeology as practiced by anthropologists is no longer only about prehistoric societies. As the world becomes increasingly preoccupied with preserving cultural heritage for future generations, archaeologists are increasingly shifting their attention from mummies and pottery to contemporary phenomena. Cultural heritage that is worth preserving could be almost anything: from Stonehenge, through to the pyramids in Egypt, to places where Star Wars or The Lord of the Rings were filmed. Even such places as the ruins of Nazi factories or Soviet war infrastructure are fragments of our history and can say something significant about our past. In fact, blockbuster films can be just as valid a topic for anthropological investigation.
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