| 1. |
- Claudino, Mauro, et al.
(författare)
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Photoinduced thiol-ene cross-linking of globalide/ε-caprolactone copolymers : curing performance and resulting thermoset properties
- 2012
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Ingår i: Journal of Polymer Science Part A. - : Wiley. - 0887-624X .- 1099-0518. ; 50:1, s. 16-24
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Tidskriftsartikel (refereegranskat)abstract
- The increasing demand for bioderived polymers led us to investigate the potential use of the macrolactone globalide in thermoset synthesis via the photoinduced thiolene reaction. A series of six lipase-catalyzed poly(globalide-caprolactone) copolyesters bearing internal main-chain unsaturations ranging from 10 to 50 and 100 mol % were successfully crosslinked in the melt with equal amounts of thiol groups from trimethylolpropane-trimercapto propionate affording fully transparent amorphous elastomeric materials with different thermal and viscoelastic properties. Three major conclusions can be drawn from this study: (i) high thiol-ene conversions (> 80%) were easily attained for all cases, while maintaining the cure behavior, and irrespective of functionality at reasonable reaction rates; (ii) parallel chain-growth homopropagation of the ene monomer is insignificant when compared with the main thiolene coupling route; and (iii) high ene-density copolymers result in much lower extracted sol fractions and high T(g) values as a result of a more dense and homogeneous crosslinked network. The thiol-ene system evaluated in this contribution serve as model example for the sustainable use of naturally occurring 1,2-disubstituted alkenes in making semisynthetic polymeric materials in high conversions with a range of properties.
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| 2. |
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| 3. |
- Nilsson, Camilla, 1979-
(författare)
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Dendrimers : Synthesis, Characterization and Use in Thiol-Ene Networks
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dendrimers are perfectly branched, well-defined macromolecules with a layered structure and a large amount of peripheral end groups. The high functionality in combination with the possibility of dendrimers to adopt a globular shape at high molecular weights, gives them very unique properties.In this work dendrimers up to fifth generation based on 2,2-bis(methylol)propionic acid (bis-MPA) were synthesized with different core structures. The core moieties were chosen in aspects of functionality and flexibility and the impact of the core on the physical and rheological properties was studied. By using the divergent growth approach dendrimers with acetonide, hydroxyl, allyl ether and methacrylate end groups were obtained.The bulk properties of the acetonide- and hydroxyl- terminated dendrimers were investigated with a rheometer. Temperature sweep tests were performed on the acetonide protected dendrimers in a temperature range of -50 up to 120°C at a constant frequency of 1 Hz. It was observed that the glass transition temperature (Tg) increased with increasing generation and that the modulus dropped without a trace of rubbery plateau for lower generations. This lack of rubbery plateau is due to the absence of entanglements between dendrimers. Interestingly, a small rubbery plateau was visible for generation five which implies enhanced interactions between the dendrimers. This behaviour suggests to be strongly influenced by the structural collapse at higher generations. Further, frequency sweep tests were performed on hydroxyl functional dendrimers at different temperatures. The results revealed Newtonian properties for lower generations and shear-thinning behaviour for higher generations at high frequency.Furthermore, this research involves the creation of well-defined thiol-ene networks by incorporation of allyl ether or methacrylate functional dendrimers in thermosets. This was accomplished by using two trithiols of different molecular weights and react them with the enes under UV irradiation. The thiol-methacrylate crosslinking reaction resulted in inhomogeneous films with and residual unsaturations. The thiol-ene films based on allyl ether dendrimers, on the contrary, resulted in homogeneous films with intermolecular couplings between the ene and the thiol being the dominant mode of polymerization.
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| 4. |
- Riddell, Michael C, et al.
(författare)
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Exercise management in type 1 diabetes: a consensus statement.
- 2017
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Ingår i: The lancet. Diabetes & endocrinology. - 2213-8595. ; 5:5, s. 377-390
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Tidskriftsartikel (refereegranskat)abstract
- Type 1 diabetes is a challenging condition to manage for various physiological and behavioural reasons. Regular exercise is important, but management of different forms of physical activity is particularly difficult for both the individual with type 1 diabetes and the health-care provider. People with type 1 diabetes tend to be at least as inactive as the general population, with a large percentage of individuals not maintaining a healthy body mass nor achieving the minimum amount of moderate to vigorous aerobic activity per week. Regular exercise can improve health and wellbeing, and can help individuals to achieve their target lipid profile, body composition, and fitness and glycaemic goals. However, several additional barriers to exercise can exist for a person with diabetes, including fear of hypoglycaemia, loss of glycaemic control, and inadequate knowledge around exercise management. This Review provides an up-to-date consensus on exercise management for individuals with type 1 diabetes who exercise regularly, including glucose targets for safe and effective exercise, and nutritional and insulin dose adjustments to protect against exercise-related glucose excursions.
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| 5. |
- Schnitzbauer, Andreas A, et al.
(författare)
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A prospective randomised, open-labeled, trial comparing sirolimus-containing versus mTOR-inhibitor-free immunosuppression in patients undergoing liver transplantation for hepatocellular carcinoma.
- 2010
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Ingår i: BMC cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The potential anti-cancer effects of mammalian target of rapamycin (mTOR) inhibitors are being intensively studied. To date, however, few randomised clinical trials (RCT) have been performed to demonstrate anti-neoplastic effects in the pure oncology setting, and at present, no oncology endpoint-directed RCT has been reported in the high-malignancy risk population of immunosuppressed transplant recipients. Interestingly, since mTOR inhibitors have both immunosuppressive and anti-cancer effects, they have the potential to simultaneously protect against immunologic graft loss and tumour development. Therefore, we designed a prospective RCT to determine if the mTOR inhibitor sirolimus can improve hepatocellular carcinoma (HCC)-free patient survival in liver transplant (LT) recipients with a pre-transplant diagnosis of HCC.
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| 6. |
- Schnitzbauer, Andreas A., et al.
(författare)
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mTOR Inhibition Is Most Beneficial After Liver Transplantation for Hepatocellular Carcinoma in Patients With Active Tumors
- 2020
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Ingår i: Annals of Surgery. - : LIPPINCOTT WILLIAMS & WILKINS. - 0003-4932 .- 1528-1140. ; 272:5, s. 855-862
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to evaluate the survival benefit of sirolimus in patients undergoing liver transplantation (LT) for hepatocellular carcinoma (HCC) (exploratory analysis of the SiLVER-trial). Summary and Background Data: Patients receiving LT) for HCC are at a high risk for tumor recurrence. Calcineurin inhibitors have shown evidence to promote cancer growth, whereas mammalian target of rapamycin (mTOR) inhibitors like sirolimus have anticancer effects. In the SiLVER-trial (Clinicaltrials.gov:NCT00355862), the effect of sirolimus on the recurrence of HCC after LTwas investigated in a prospective randomized trial. Although the primary endpoint of improved disease-free survival (DFS) with sirolimus was not met, outcomes were improved for patients in the sirolimus-treatment arm in the first 3 to 5 years. To learn more about the key variables, a multivariate analysis was performed on the SiLVER-trial data. Patients and Methods: Data from 508 patients of the intention-to-treat analysis were included in exploratory univariate and multivariate models for overall survival (OS), DFS and a competing risk analysis for HCC recurrence. Results: Sirolimus use for >= 3 months after LT for HCC independently reduced the hazard for death in the multivariate analysis [hazard ratio (HR): 0.7 (95% confidence interval, CI: 0.52-0.96, P = 0.02). Most strikingly, patients with an alpha-fetoprotein (AFP) >= 10 ng/mL and having used sirolimus for >= 3 months, benefited most with regard to OS, DFS, and HCC-recurrence (HR: 0.49- 0.59, P = 0.0079- 0.0245). Conclusions: mTOR-inhibitor treatment with sirolimus for >= 3 months improves outcomes in LT for HCC, especially in patients with AFP-evidence of higher tumor activity, advocating particularly for mTOR inhibitor use in this subgroup of patients. Clinical Trial Registration: EudraCT: 2005-005362-36 Clinicaltrials.gov: NCT00355862.
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| 7. |
- Takwa, Mohamad, et al.
(författare)
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Lipase Catalyzed HEMA Initiated Ring-Opening Polymerization : In Situ Formation of Mixed Polyester Methacrylates by Transesterification
- 2008
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 9:2, s. 704-710
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Tidskriftsartikel (refereegranskat)abstract
- 2-Hydroxyethyl methacrylate (HEMA) was used as initiator for the enzymatic ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) and ∈-caprolactone (CL). The lipase B from Candida antarctica was found to catalyze the cleavage of the ester bond in the HEMA end group of the formed polyesters, resulting in two major transesterification processes, methacrylate transfer and polyester transfer. This resulted in a number of different polyester methacrylate structures, such as polymers without, with one, and with two methacrylate end groups. Furthermore, the 1,2-ethanediol moiety (from HEMA) was found in the polyester products as an integral part of HEMA, as an end group (with one hydroxyl group) and incorporated within the polyester (polyester chains acylated on both hydroxyl groups). After 72 h, as a result of the methacrylate transfer, 79% (48%) of the initial amount of the methacrylate moiety (from HEMA) was situated (acylated) on the end hydroxyl group of the PPDL (PCL) polyester. In order to prepare materials for polymer networks, fully dimethacrylated polymers were synthesized in a one-pot procedure by combining HEMA-initiated ROP with end-capping using vinyl methacrylate. The novel PPDL dimethacrylate (>95% incorporated methacrylate end groups) is currently in use for polymer network formation. Our results show that initiators with cleavable ester groups are of limited use to obtain well-defined monomethacrylated macromonomers due to the enzyme-based transesterification processes. On the other hand, when combined with end-capping, well-defined dimethacrylated polymers (PPDL, PCL) were prepared.
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| 8. |
- Xiao, Yan, et al.
(författare)
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Systematic Comparison of HEA and HEMA as Initiators in Enzymatic Ring-Opening Polymerizations
- 2009
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Ingår i: Macromolecular Bioscience. - : Wiley. - 1616-5187 .- 1616-5195. ; 9:7, s. 713-720
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Tidskriftsartikel (refereegranskat)abstract
- Two initiators (HEA and HEMA) containing a cleavable ester bond were compared in the lipase-catalyzed ROP of CL and PDL. HEA and HEMA displayed similar reaction efficiencies as initiators (acyl acceptors) in the enzymatic ROP. However, transacylation reactions were found to be 15 times faster on the HEA-initiated polyesters as compared with the HEAAA initiated polyesters (HEA/HEMA moieties as acyl donors). While in both cases the amount of HEA- and HEMA-initiated polymers could be maximized by H short reaction times, a well-defined (meth)acrylation by this approach was not possible. Our results show that trans esterification reactions are present at high rates throughout the enzyme-catalyzed ROP.
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