| 1. |
- Segerholm, Kristoffer, et al.
(författare)
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Micromorphology, moisture sorption and mechanical properties of a biocomposite based on acetylated wood particles and cellulose ester
- 2007
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Ingår i: Wood Material Science and Engineering. - : Informa UK Limited. - 1748-0272 .- 1748-0280. ; 3-4:2, s. 106-117
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Tidskriftsartikel (refereegranskat)abstract
- One of the major issues in a long-term perspective for the use of wood-plastic composites (WPCs) in outdoor applications is the moisture sensitivity of the wood component and the consequent dimensional instability and susceptibility to biological degradation of the composite. In this work, the effects of using an acetylated wood component and a cellulose ester as matrix on the micromorphology, mechanical performance and moisture uptake of injection-moulded WPCs have been studied. Composites based on unmodified and acetylated wood particles, specially designed with a length-to-width ratio of about 5-7, combined with both cellulose acetate propionate (CAP) and polypropylene (PP) matrices were studied. The size and shape of the wood particles were studied before and after the processing using light microscopy, and the micromorphology of the composites was studied using a newly developed surface preparation technique based on ultraviolet laser irradiation combined with low-vacuum scanning electron microscopy (LV-SEM). The water vapour sorption in the composites and the effect of accelerated weathering were measured using thin samples which were allowed to reach equilibrium moisture content (EMC). The length-to-diameter ratio was only slightly decreased for the acetylated particles after compounding and injection moulding, although both the unmodified and the acetylated particles were smaller in size after the processing steps. The tensile strength was about 40% higher for the composite based on acetylated wood than for the composite with unmodified wood using either CAP or PP as matrix, whereas the notched impact strength of the composite based on acetylated wood was about 20% lower than those of the corresponding unmodified composites. The sorption experiments showed that the EMC was 50% lower in the composites with an acetylated wood component than in the composites with an unmodified wood component. The choice of matrix material strongly affected the moisture absorptivity of the WPC. The composites with CAP as matrix gained moisture more rapidly than the composites with PP as matrix. It was also found that accelerated ageing in a Weather-Ometer® significantly increased the moisture sensitivity of the PP-based composites.
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| 2. |
- Carlson, Lena-Maria, et al.
(författare)
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Differentiation induced by physiological and pharmacological stimuli leads to increased antigenicity of human neuroblastoma cells
- 2008
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Ingår i: Cell Research. - : Springer Science and Business Media LLC. - 1748-7838 .- 1001-0602. ; 18:3, s. 398-411
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Tidskriftsartikel (refereegranskat)abstract
- Sympathetic neuronal differentiation is associated with favorable prognosis of neuroblastoma (NB), the most common extra-cranial solid tumor of early childhood. Differentiation agents have proved useful in clinical protocols of NB treatment, but using them as a sole treatment is not sufficient to induce tumor elimination in patients. Therefore, complementary approaches, such as immunotherapy, are warranted. Here we demonstrate that differentiation of NB cell lines and ex vivo isolated tumor cells in response to physiological or pharmacological stimuli is associated with acquisition of increased antigenicity. This manifests as increased expression of surface major histocompatibility class I complexes and ICAM-1 molecules and translates into increased sensitivity of NB cells to lysis by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. The latter is paralleled by enhanced ability of differentiated cells to form immune conjugates and bind increased amounts of granzyme B to the cell surface. We demonstrate, for the first time, that, regardless of the stimulus applied, the differentiation state in NBs is associated with increased tumor antigenicity that enables more efficient elimination of tumor cells by cytotoxic lymphocytes and paves the way for combined application of differentiation-inducing agents and immunotherapy as an auxiliary approach in NB patients.
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| 3. |
- Djupedal, Ingela, et al.
(författare)
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Epigenetics : heterochromatin meets RNAi
- 2009
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Ingår i: Cell Research. - : Springer Science and Business Media LLC. - 1001-0602 .- 1748-7838. ; 19:3, s. 282-295
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Tidskriftsartikel (refereegranskat)abstract
- The term epigenetics refers to heritable changes not encoded by DNA. The organization of DNA into chromatin fibers affects gene expression in a heritable manner and is therefore one mechanism of epigenetic inheritance. Large parts of eukaryotic genomes consist of constitutively highly condensed heterochromatin, important for maintaining genome integrity but also for silencing of genes within. Small RNA, together with factors typically associated with RNA interference (RNAi) targets homologous DNA sequences and recruits factors that modify the chromatin, commonly resulting in formation of heterochromatin and silencing of target genes. The scope of this review is to provide an overview of the roles of small RNA and the RNAi components, Dicer, Argonaute and RNA dependent polymerases in epigenetic inheritance via heterochromatin formation, exemplified with pathways from unicellular eukaryotes, plants and animals.
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| 4. |
- Lönn, Peter, et al.
(författare)
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Regulating the stability of TGFβ receptors and Smads
- 2009
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Ingår i: Cell Research. - : IBCB, SIBS, CAS. - 1001-0602 .- 1748-7838. ; 19:1, s. 21-35
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Forskningsöversikt (refereegranskat)abstract
- Transforming growth factor beta (TGFbeta) controls cellular behavior in embryonic and adult tissues. TGFbeta binding to serine/threonine kinase receptors on the plasma membrane activates Smad molecules and additional signaling proteins that together regulate gene expression. In this review, mechanisms and models that aim at explaining the coordination between several components of the signaling network downstream of TGFbeta are presented. We discuss how the activity and duration of TGFbeta receptor/Smad signaling can be regulated by post-translational modifications that affect the stability of key proteins in the pathway. We highlight links between these mechanisms and human diseases, such as tissue fibrosis and cancer.
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