| 1. |
- Bjurhager, Ingela, et al.
(author)
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Ultrastructure and Mechanical Properties of Populus Wood with Reduced Lignin Content Caused by Transgenic Down-Regulation of Cinnamate 4-Hydroxylase
- 2010
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 11:9, s. 2359-2365
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Journal article (peer-reviewed)abstract
- Several key enzymes in lignin biosynthesis of Populus have been down-regulated by transgenie approaches to investigate their role in wood lignification and to explore their potential for lignin modification. Cinnamate 4-hydroxylase is an enzyme in the early phenylpropanoid pathway that has not yet been functionally analyzed in Populus. This study shows that down-regulation of cinnamate 4-hydroxylase reduced Klason lignin content by 30% with no significant change in syringyl to guaiacyl ratio. The lignin reduction resulted in ultrastructural differences of the wood and a 10% decrease in wood density. Mechanical properties investigated by tensile tests and dynamic mechanical analysis showed a decrease in stiffness, which could be explained by the lower density. The study demonstrates that a large modification in lignin content only has minor influences on tensile properties of wood in its axial direction and highlights the usefulness of wood modified beyond its natural variation by transgene technology in exploring the impact of wood biopolymer composition and ultrastructure on its material properties.
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| 2. |
- Gao, Jiajia, et al.
(author)
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Light-induced electrolyte improvement in cobalt tris(bipyridine)-mediated dye-sensitized solar cells
- 2019
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 7:33, s. 19495-19505
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Journal article (peer-reviewed)abstract
- Lithium-ion-free tris(2,2′-bipyridine) Co(ii/iii)-mediated electrolytes have previously been proposed for long-term stable dye-sensitized solar cells (DSSCs). Such redox systems also offer an impressive DSSC performance improvement under light soaking exposure, manifested by an increase in photocurrent and fill factor without the expense of decreasing photovoltage. Kinetic studies show that charge transfer and ion diffusion at the electrode/electrolyte interface are improved due to the light exposure. Control experiments reveal that the light effect is unambiguously associated with electrolyte components, [Co(bpy)3]3+ and the Lewis-base additive tert-butylpyridine (TBP). Electrochemical and spectroscopic investigation of the [Co(bpy)3]3+/TBP mixtures points out that the presence of TBP, which retards the electrolyte diffusion, however causes an irreversible redox reaction of [Co(bpy)3]3+ upon light exposure that improves the overall conductivity. This discovery not only provides a new strategy to mitigate the typical Jsc-Voc trade-off in Co(ii/iii)-mediated DSSCs but also highlights the importance of investigating the photochemistry of a photoelectrochemical system.
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| 3. |
- Gurrani, Swapnil, et al.
(author)
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Biomass Hydrolyzing Enzymes
- 2024
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In: <em>Biomass Hydrolyzing Enzymes: Basics, Advancements, and Applications</em>. - : CRC Press. ; , s. 3-13
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Book chapter (other academic/artistic)abstract
- Lignocellulosic biomass is the most abundant, ubiquitous polymer on Earth available to benefit mankind. Biomass biorefinery has taken center stage in the world’s economy and is becoming diverse with time. With biorefinery, cascades of products can be obtained from biomass rather than a single product. It is a complex structure that consists of three polymers as cellulose, hemicellulose and lignin, linked to each other in a compact intricate manner making it difficult to be attacked by microorganisms. Still, many microorganisms have evolved strategies to consume this abundant material as an energy source. Degradation of lignocellulosic biomass is not only a survival strategy for these microbes, but its destruction also plays a pivotal role in carbon recycling of Earth through the fixation of photosynthetically fixed carbon present in plant biomass. Mankind has explored the capacity of microorganisms to produce polymer-degrading enzymes to deconstruct its basic components. Biomass-degrading enzymes have attracted researchers worldwide as this is the most sustainable way to obtain fermentable sugars from this most abundant biomass. Synergism among enzymes as well as their various components are presented along with challenges of biomass hydrolysis and probable solutions. © 2024 selection and editorial matter, Reeta Rani Singhania, Anil Kumar Patel, Héctor A. Ruiz, Ashok Pandey; individual chapters, the contributors.
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| 4. |
- Jayaraman, R., et al.
(author)
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Effective Resource Allocation Technique to Improve QoS in 5G Wireless Network
- 2023
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In: Electronics. - : MDPI. - 2079-9292. ; 12:2
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Journal article (peer-reviewed)abstract
- A 5G wireless network requires an efficient approach to effectively manage and segment the resource. A Centralized Radio Access Network (CRAN) is used to handle complex distributed networks. Specific to network infrastructure, multicast communication is considered in the performance of data storage and information-based network connectivity. This paper proposes a modified Resource Allocation (RA) scheme for effectively handling the RA problem using a learning-based Resource Segmentation (RS) technique. It uses a modified Random Forest Algorithm (RFA) with Signal Interference and Noise Ratio (SINR) and position coordinates to obtain the position coordinates of end-users. Further, it predicts Modulation and Coding Schemes (MCS) for establishing a connection between the end-user device and the Remote Radio Head (RRH). The proposed algorithm depends on the accuracy of positional coordinates for the correctness of the input parameters, such as SINR, based on the position and orientation of the antenna. The simulation analysis renders the efficiency of the proposed technique in terms of throughput and energy efficiency. © 2023 by the authors.
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| 5. |
- Karsten, Stella, et al.
(author)
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MTH1 as a target to alleviate T cell driven diseases by selective suppression of activated T cells
- 2021
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In: Cell Death & Differentiation. - Stockholm : Karolinska Institutet, Dept of Oncology-Pathology. - 1350-9047 .- 1476-5403.
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Journal article (peer-reviewed)abstract
- T cell-driven diseases account for considerable morbidity and disability globally and there is an urgent need for new targeted therapies. Both cancer cells and activated T cells have an altered redox balance, and up-regulate the DNA repair protein MTH1 that sanitizes the oxidized nucleotide pool to avoid DNA damage and cell death. Herein we suggest that the up-regulation of MTH1 in activated T cells correlates with their redox status, but occurs before the ROS levels increase, challenging the established conception of MTH1 increasing as a direct response to an increased ROS status. We also propose a heterogeneity in MTH1 levels among activated T cells, where a smaller subset of activated T cells does not upregulate MTH1 despite activation and proliferation. The study suggests that the vast majority of activated T cells have high MTH1 levels and are sensitive to the MTH1 inhibitor TH1579 (Karonudib) via induction of DNA damage and cell cycle arrest. TH1579 further drives the surviving cells to the MTH1[superscript low] phenotype with altered redox status. TH1579 does not affect resting T cells, as opposed to the established immunosuppressor Azathioprine, and no sensitivity among other major immune cell types regarding their function can be observed. Finally, we demonstrate a therapeutic effect in a murine model of experimental autoimmune encephalomyelitis. In conclusion, we show proof of concept of the existence of MTH1[superscript high] and MTH1[superscript low] activated T cells, and that MTH1 inhibition by TH1579 selectively suppresses pro-inflammatory activated T cells. Thus, MTH1 inhibition by TH1579 may serve as a novel treatment option against autoreactive T cells in autoimmune diseases, such as multiple sclerosis.
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| 6. |
- Kuna, Vijay Kumar, 1987, et al.
(author)
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Successful tissue engineering of competent allogeneic venous valves
- 2015
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In: Journal of Vascular Surgery. - : Elsevier Inc.. - 0741-5214. ; 3:4, s. 421-430
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Journal article (peer-reviewed)abstract
- Objective The purpose of this study was to evaluate whether tissue-engineered human allogeneic vein valves have a normal closure time (competency) and tolerate reflux pressure in vitro. Methods Fifteen human allogeneic femoral vein segments containing valves were harvested from cadavers. Valve closure time and resistance to reflux pressure (100 mm Hg) were assessed in an in vitro model to verify competency of the vein valves. The segments were tissue engineered using the technology of decellularization (DC) and recellularization (RC). The decellularized and recellularized vein segments were characterized biochemically, immunohistochemically, and biomechanically. Results Four of 15 veins with valves were found to be incompetent immediately after harvest. In total, 2 of 4 segments with incompetent valves and 10 of 11 segments with competent valves were further decellularized using detergents and DNAse. DC resulted in significant decrease in host DNA compared with controls. DC scaffolds, however, retained major extracellular matrix proteins and mechanical integrity. RC resulted in successful repopulation of the lumen and valves of the scaffold with endothelial and smooth muscle cells. Valve mechanical parameters were similar to the native tissue even after DC. Eight of 10 veins with competent valves remained competent even after DC and RC, whereas the two incompetent valves remained incompetent even after DC and RC. The valve closure time to reflux pressure of the tissue-engineered veins was <0.5 second. Conclusions Tissue-engineered veins with valves provide a valid template for future preclinical studies and eventual clinical applications. This technique may enable replacement of diseased incompetent or damaged deep veins to treat axial reflux and thus reduce ambulatory venous hypertension. Copyright © 2015 by the Society for Vascular Surgery. Published by Elsevier Inc.
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| 7. |
- Rudd, Sean, et al.
(author)
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Ribonucleotide reductase inhibitors suppress SAMHD1 ara-CTPase activity enhancing cytarabine efficacy
- 2020
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In: EMBO Molecular Medicine. - : Blackwell Publishing Ltd. - 1757-4676 .- 1757-4684.
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Journal article (peer-reviewed)abstract
- The deoxycytidine analogue cytarabine (ara-C) remains the backbone treatment of acute myeloid leukaemia (AML) as well as other haematological and lymphoid malignancies, but must be combined with other chemotherapeutics to achieve cure. Yet, the underlying mechanism dictating synergistic efficacy of combination chemotherapy remains largely unknown. The dNTPase SAMHD1, which regulates dNTP homoeostasis antagonistically to ribonucleotide reductase (RNR), limits ara-C efficacy by hydrolysing the active triphosphate metabolite ara-CTP. Here, we report that clinically used inhibitors of RNR, such as gemcitabine and hydroxyurea, overcome the SAMHD1-mediated barrier to ara-C efficacy in primary blasts and mouse models of AML, displaying SAMHD1-dependent synergy with ara-C. We present evidence that this is mediated by dNTP pool imbalances leading to allosteric reduction of SAMHD1 ara-CTPase activity. Thus, SAMHD1 constitutes a novel biomarker for combination therapies of ara-C and RNR inhibitors with immediate consequences for clinical practice to improve treatment of AML. © 2020 The Authors. Published under the terms of the CC BY 4.0 license
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