| 1101. |
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| 1102. |
- Kuster, Roman P, et al.
(författare)
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Active sitting with backrest support : is it feasible?
- 2018
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Ingår i: Ergonomics. - Stockholm : Karolinska Institutet, Dept of Neurobiology, Care Sciences and Society. - 0014-0139 .- 1366-5847.
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Tidskriftsartikel (refereegranskat)abstract
- Ergonomics science recommends office chairs that promote active sitting to reduce sitting related complaints. Since current office chairs do not fulfil this recommendation, a new chair was developed by inverting an existing dynamic chair principle. This study compares active sitting on the inverted chair during a simulated computer based office task to two existing dynamic office chairs (n=8). Upper body stability was analysed using Friedman ANOVA (p=.01). Additionally, participants completed a questionnaire to rate their comfort and activity after half a working day. The inverted chair allowed the participants to perform a substantial range of lateral spine flexion (11.5°) with the most stable upper body posture (≤11mm, ≤2°, p≤0.01). The results of this study suggest that the inverted chair supports active sitting with backrest support during computer based office work. However, according to comfort and activity ratings, results should be verified in a future field study with 24 participants.
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| 1103. |
- Liberles, David A., et al.
(författare)
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The interface of protein structure, protein biophysics, and molecular evolution
- 2012
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Ingår i: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 21:6, s. 769-785
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Forskningsöversikt (refereegranskat)abstract
- The interface of protein structural biology, protein biophysics, molecular evolution, and molecular population genetics forms the foundations for a mechanistic understanding of many aspects of protein biochemistry. Current efforts in interdisciplinary protein modeling are in their infancy and the state-of-the art of such models is described. Beyond the relationship between amino acid substitution and static protein structure, protein function, and corresponding organismal fitness, other considerations are also discussed. More complex mutational processes such as insertion and deletion and domain rearrangements and even circular permutations should be evaluated. The role of intrinsically disordered proteins is still controversial, but may be increasingly important to consider. Protein geometry and protein dynamics as a deviation from static considerations of protein structure are also important. Protein expression level is known to be a major determinant of evolutionary rate and several considerations including selection at the mRNA level and the role of interaction specificity are discussed. Lastly, the relationship between modeling and needed high-throughput experimental data as well as experimental examination of protein evolution using ancestral sequence resurrection and in vitro biochemistry are presented, towards an aim of ultimately generating better models for biological inference and prediction.
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| 1104. |
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| 1105. |
- Lossow, Stefan, 1977, et al.
(författare)
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A reassessment of the discrepancies in the annual variation of δD-H2O in the tropical lower stratosphere between the MIPAS and ACE-FTS satellite data sets
- 2020
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 13:1, s. 287-308
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Tidskriftsartikel (refereegranskat)abstract
- The annual variation of δD in the tropical lower stratosphere is a critical indicator for the relative importance of different processes contributing to the transport of water vapour through the cold tropical tropopause region into the stratosphere. Distinct observational discrepancies of the δD annual variation were visible in the works of Steinwagner et al. (2010) and Randel et al. (2012). Steinwagner et al. (2010) analysed MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) observations retrieved with the IMK/IAA (Institut für Meteorologie und Klimaforschung in Karlsruhe, Germany, in collaboration with the Instituto de Astrofísica de Andalucía in Granada, Spain) processor, while Randel et al. (2012) focused on ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) observations. Here we reassess the discrepancies based on newer MIPAS (IMK/IAA) and ACE-FTS data sets, also showing for completeness results from SMR (Sub-Millimetre Radiometer) observations and a ECHAM/MESSy (European Centre for Medium-Range Weather Forecasts Hamburg and Modular Earth Submodel System) Atmospheric Chemistry (EMAC) simulation (Eichinger et al., 2015b). Similar to the old analyses, the MIPAS data set yields a pronounced annual variation (maximum about 75 ‰), while that derived from the ACE-FTS data set is rather weak (maximum about 25 ‰). While all data sets exhibit the phase progression typical for the tape recorder, the annual maximum in the ACE-FTS data set precedes that in the MIPAS data set by 2 to 3 months. We critically consider several possible reasons for the observed discrepancies, focusing primarily on the MIPAS data set. We show that the δD annual variation in the MIPAS data up to an altitude of 40 hPa is substantially impacted by a “start altitude effect”, i.e. dependency between the lowermost altitude where MIPAS retrievals are possible and retrieved data at higher altitudes. In itself this effect does not explain the differences with the ACE-FTS data. In addition, there is a mismatch in the vertical resolution of the MIPAS HDO and H2O data (being consistently better for HDO), which actually results in an artificial tape-recorder-like signal in δD. Considering these MIPAS characteristics largely removes any discrepancies between the MIPAS and ACE-FTS data sets and shows that the MIPAS data are consistent with a δD tape recorder signal with an amplitude of about 25 ‰ in the lowermost stratosphere.
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| 1106. |
- Madl, Christopher M., et al.
(författare)
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Maintenance of neural progenitor cell stemness in 3D hydrogels requires matrix remodelling
- 2017
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122. ; 16:12, s. 1233-1242
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Tidskriftsartikel (refereegranskat)abstract
- Neural progenitor cell (NPC) culture within three-dimensional (3D) hydrogels is an attractive strategy for expanding a therapeutically relevant number of stem cells. However, relatively little is known about how 3D material properties such as stiffness and degradability affect the maintenance of NPC stemness in the absence of differentiation factors. Over a physiologically relevant range of stiffness from â 1/40.5 to 50 kPa, stemness maintenance did not correlate with initial hydrogel stiffness. In contrast, hydrogel degradation was both correlated with, and necessary for, maintenance of NPC stemness. This requirement for degradation was independent of cytoskeletal tension generation and presentation of engineered adhesive ligands, instead relying on matrix remodelling to facilitate cadherin-mediated cell-cell contact and promote ?-catenin signalling. In two additional hydrogel systems, permitting NPC-mediated matrix remodelling proved to be a generalizable strategy for stemness maintenance in 3D. Our findings have identified matrix remodelling, in the absence of cytoskeletal tension generation, as a previously unknown strategy to maintain stemness in 3D.
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| 1107. |
- Malmqvist, Anna, et al.
(författare)
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Increased peripheral levels of TARC/CCL17 in first episode psychosis patients
- 2019
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Ingår i: Schizophrenia Research. - : ELSEVIER. - 0920-9964 .- 1573-2509. ; 210, s. 221-227
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Tidskriftsartikel (refereegranskat)abstract
- Background: Evidence for a link between the pathophysiology of schizophrenia and the immune system is mounting. Altered levels of chemokines in plasma have previously been reported in patients with schizophrenia under antipsychotic medication. Here we aimed to study both peripheral and central chemokine levels in drugnaive or short-time medicated first episode psychosis (FEP) patients. Method: We analyzed nine chemokines in plasma and CSF from 41 FEP patients and 22 healthy controls using electrochemiluminescence assay. Results: In plasma four chemokines; TARC/CCL17, eotaxin/CCL11, MDC/CCL22, IP-10/CXCL10 and in CSF one chemokine; IP-10/CXCL10 showed reliable detection in N50% of the cases. FEP patients displayed increased levels of TARC/CCL17 in plasma compared to healthy controls, 89.6 (IQR 66.2-125.8) pg/mL compared to 48.6 (IQR 28.0-71.7) pg/mL (p = 0.001). The difference was not attributed to confounding factors. Plasma TARC/CCL17 was not associated with PANSS, CGI or GAF scores, neither with cognitive functions. The chemokines eotaxin/CCL11, MDC/CCL22, IP-10/CXCL10 in plasma and IP-10/CXCL10 in CSF did not differ between FEP patients and controls. Conclusion: In line with a previous study showing that chronic patients with schizophrenia display increased plasma TARC/CCL17 levels, we here found an elevation in FEP patients suggesting a role of TARC/CCL17 in early stages of schizophrenia. The exactmechanism of this involvement is still unknown and future longitudinal studies as well as studies of central and peripheral chemokine levels would be of great interest. (C) 2018 Elsevier B.V. All rights reserved.
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| 1108. |
- Martin, Natalia Mihaela, 1984, et al.
(författare)
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Catalytic hydrogenation of CO2 to methane over supported Pd, Rh and Ni catalysts
- 2017
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Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 7:5, s. 1086-1094
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Tidskriftsartikel (refereegranskat)abstract
- As a step in production of so-called electrofuels, ambient pressure CO2 hydrogenation has been investigated over different catalytic model systems based on metal particles (Pd, Rh and Ni) supported on various metal oxides (SiO2, Al2O3 and CeO2) and aluminosilicates (ZSM-5 and MCM-41) at different specific reactant ratios and temperatures between 150 and 450 degrees C. Catalytic activity and selectivity measurements in a flow reactor show that the highest CO2 conversion towards methane is obtained for the Rh/Al2O3 and Rh/CeO2 catalysts, followed by Ni/CeO2. Generally, the results suggest that both the support material and reaction conditions play an important role in the hydrogenation process. Further, in situ diffusive reflectance infrared Fourier transform spectroscopy reveals the intermediate species during transient CO2 hydrogenation over the Rh and Ni containing catalysts. Adsorption and dissociation of CO2 occurs over the Rh/Al2O3 catalyst in the presence of H-2, resulting in the formation of linear Rh-CO species, while formates and carbonates are formed over the Rh/CeO2 and Ni/CeO2 catalysts, likely at the metal-support interface.
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| 1109. |
- Martin, Natalia M., et al.
(författare)
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Structure-function relationship for CO2 methanation over ceria supported Rh and Ni catalysts under atmospheric pressure conditions
- 2019
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Ingår i: Catalysis Science & Technology. - : Royal Society of Chemistry. - 2044-4753 .- 2044-4761. ; 9:7, s. 1644-1653
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Tidskriftsartikel (refereegranskat)abstract
- In situ structural and chemical state characterization of Rh/CeO2 and Ni/CeO2 catalysts during atmospheric pressure CO2 methanation has been performed by a combined array of time-resolved analytical techniques including ambient-pressure X-ray photoelectron spectroscopy, high-energy X-ray diffraction and diffuse reflectance infrared Fourier transform spectroscopy. The ceria phase is partially reduced during the CO2 methanation and in particular Ce3+ species seem to facilitate activation of CO2 molecules. The activated CO2 molecules then react with atomic hydrogen provided from H-2 dissociation on Rh and Ni sites to form formate species. For the most active catalyst (Rh/CeO2), transmission electron microscopy measurements show that the Rh nanoparticles are small (average 4 nm, but with a long tail towards smaller particles) due to a strong interaction between Rh particles and the ceria phase. In contrast, larger nanoparticles were observed for the Ni/CeO2 catalyst (average 6 nm, with no crystallites below 5 nm found), suggesting a weaker interaction with the ceria phase. The higher selectivity towards methane of Rh/CeO2 is proposed to be due to the stronger metal-support interaction.
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| 1110. |
- Marton, Z., et al.
(författare)
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Mutations in the stereospecificity pocket and at the entrance of the active site of Candida antarctica lipase B enhancing enzyme enantioselectivity
- 2010
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Ingår i: Journal of Molecular Catalysis B. - : Elsevier BV. - 1381-1177 .- 1873-3158. ; 65:1-4, s. 11-17
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Tidskriftsartikel (refereegranskat)abstract
- Two different parts of Candida antarctica lipase B (stereospecificity pocket at the bottom of the active site and hydrophobic tunnel leading to the active site) were redesigned by single- or double-point mutations, in order to better control and improve enzyme enantioselectivity toward secondary alcohols. Single-point isosteric mutations of Ser47 and Thr42 situated in the stereospecificity pocket gave rise to variants with doubled enantioselectivity toward pentan-2-ol, in solid/gas reactor. Besides, the width and shape of the hydrophobic tunnel leading to the active site was modified by producing the following single-point mutants: Ile189Ala, Leu278Val and Ala282Leu. For each of these variants a significant modification of enantioselectivity was observed compared to wild-type enzyme, indicating that discrimination of the enantiomers by the enzyme could also arise from their different accessibilities from the enzyme surface to the catalytic site. (C) 2010 Elsevier B.V. All rights reserved.
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