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  • 1.
    Abbas, S.
    et al.
    Quaid-i-Azam University, Pakistan.
    Imtiaz-ud-Din,
    Quaid-i-Azam University, Pakistan.
    Mehmood, M.
    Quaid-i-Azam University, Pakistan.
    Raheel, A.
    Quaid-i-Azam University, Pakistan.
    Ayub, Rabia
    RISE Research Institutes of Sweden, Bioeconomy and Health, Biorefinery and Energy.
    Zahid, M.
    Higher Education Department Govt. of the Punjab, Pakistan.
    Tahir, M. N.
    University of Sargodha, Pakistan.
    Synthesis and Structural Characterization of Bioactive Ferrocenyl Substituted Hydrazones2021In: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 47, no 12, p. 891-902Article in journal (Refereed)
    Abstract [en]

    A series of ferrocenyl substituted hydrazones (I–VII) derived from ferrocene carboxaldehyde and substituted hydrazides have been prepared and characterized by FTIR, 1H NMR spectroscopy, and crystallographic studies. The single-crystal X-ray analysis for III·0.5H2O·0.5CH3CN (CIF file CCDC no. 1968937) further authenticates the structural motif of the synthesized compounds. The C(11) of ferrocene carboxaldehyde is linked with N(1) of the hydrazide moiety with a bond length of 1.283(5) Å, confirming the binding of the two structural units present in the final product. They were preliminarily screened for their antimicrobial activity and demonstrate good results. The free radical scavenging activity for the compounds (III, IV) has been found to be more than 90% when compared with the ascorbic acid. The total antioxidant capacity and total reducing power assays for VI show significant activity whereas the data for the other compounds are also encouraging. Quantum chemical calculations at the DFT level predict that compound II is the softest while VII is the hardest within the series, resultantly II can be used as a synthon for further chemical reactions.

  • 2.
    Ankerfors, Mikael
    et al.
    RISE, Innventia.
    Duker, Elisabeth
    BillerudKorsnäs AB, Sweden.
    Lindström, Tom
    RISE, Innventia.
    Topo-chemical modification of fibres by grafting of carboxymethyl cellulose in pilot scale2013In: Nordic Pulp and Paper Research Journal, ISSN 0283-2631 , no 1, p. 6-14Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to graft carboxymethyl cellulose (CMC) on to bleached softwood kraft pulp at temperatures below 100°C and to do a pilot paper machine trial in order to examine the influence of the CMC on dewatering, sheet formation and mechanical properties. During the pilot trial, one CMC grafted pulp was compared to a pulp with 3 different refining degrees. It was shown that CMC-grafting improves the mechanical properties of paper with only a minor effect on the sheet density. It was also shown that the CMC grafting is less detrimental to dewatering than refining and at a certain tensile index a higher dry content after pressing could be reached. The formation number of the paper produced in the FEX trial was not significantly affected by the addition of CMC.

  • 3.
    Athley, Karin
    et al.
    RISE, Innventia.
    Granlöf, Lars
    RISE, Innventia.
    Söderberg, Daniel
    RISE, Innventia.
    Ström, Göran
    RISE, Innventia.
    Optimizing the benefit of retention chemicals2014Conference paper (Refereed)
    Abstract [en]

    Pre-flocculation of filler has been tested as a concept for improving the retention of filler and the strength properties of the sheet. The impact of the size of the filler floes on the mechanical retentionin a fibre network was investigated using a modified laboratory hand sheet former. The mechanical retention was found to increase linearly with both particle size and grammage of the fibre web. These results were confirmed in a full scale production trial on the FEX pilot paper machine at Innventia. Here different filler floe sizes were created through different chemical pre-flocculation strategies. The particle size in the flow to the headbox was measured with FBRM, and a linear relation between particle size and filler retention was found. Corresponding linear relation was seen in a pilot trial when adding filler and retention aid conventionally. This implies that mechanical retention constitute an important part of the filler retention not only upon pre-flocculation but also with conventional addition of filler and retention aid. Thus, the particle size before the headbox can be a good indicator of the retention level. For the conventional application of a two component retention aid system, the increased filler retention correlated to impaired formation and decreased sheet strength. On the contrary, pre-flocculation led to an increase in both sheet strength and filler retention, demonstrating the advantage of pre-flocculating filler.

  • 4.
    Ayub, Rabia
    et al.
    Uppsala University, Sweden.
    Bakouri, O. E.
    Jorner, K.
    Solà, M.
    Ottosson, H.
    Can Baird's and Clar's Rules Combined Explain Triplet State Energies of Polycyclic Conjugated Hydrocarbons with Fused 4nπ- and (4n + 2)π-Rings?2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 12, p. 6327-6340Article in journal (Refereed)
    Abstract [en]

    Compounds that can be labeled as "aromatic chameleons" are π-conjugated compounds that are able to adjust their π-electron distributions so as to comply with the different rules of aromaticity in different electronic states. We used quantum chemical calculations to explore how the fusion of benzene rings onto aromatic chameleonic units represented by biphenylene, dibenzocyclooctatetraene, and dibenzo[a,e]pentalene modifies the first triplet excited states (T1) of the compounds. Decreases in T1 energies are observed when going from isomers with linear connectivity of the fused benzene rings to those with cis- or trans-bent connectivities. The T1 energies decreased down to those of the parent (isolated) 4nπ-electron units. Simultaneously, we observe an increased influence of triplet state aromaticity of the central 4n ring as given by Baird's rule and evidenced by geometric, magnetic, and electron density based aromaticity indices (HOMA, NICS-XY, ACID, and FLU). Because of an influence of triplet state aromaticity in the central 4nπ-electron units, the most stabilized compounds retain the triplet excitation in Baird π-quartets or octets, enabling the outer benzene rings to adapt closed-shell singlet Clar π-sextet character. Interestingly, the T1 energies go down as the total number of aromatic cycles within a molecule in the T1 state increases. 

  • 5.
    Ayub, Rabia
    et al.
    Uppsala University, Sweden.
    El Bakouri, O.
    Smith, J. R.
    Jorner, K.
    Ottosson, H.
    Triplet State Baird Aromaticity in Macrocycles: Scope, Limitations, and Complications2021In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 125, no 2, p. 570-584Article in journal (Refereed)
    Abstract [en]

    The aromaticity of cyclic 4nπ-electron molecules in their first ππ∗ triplet state (T1), labeled Baird aromaticity, has gained growing attention in the past decade. Here we explore computationally the limitations of T1 state Baird aromaticity in macrocyclic compounds, [n]CM's, which are cyclic oligomers of four different monocycles (M = p-phenylene (PP), 2,5-linked furan (FU), 1,4-linked cyclohexa-1,3-diene (CHD), and 1,4-linked cyclopentadiene (CPD)). We strive for conclusions that are general for various DFT functionals, although for macrocycles with up to 20 π-electrons in their main conjugation paths we find that for their T1 states single-point energies at both canonical UCCSD(T) and approximative DLPNO-UCCSD(T) levels are lowest when based on UB3LYP over UM06-2X and UCAM-B3LYP geometries. This finding is in contrast to what has earlier been observed for the electronic ground state of expanded porphyrins. Yet, irrespective of functional, macrocycles with 2,5-linked furans ([n]CFU's) retain Baird aromaticity until larger n than those composed of the other three monocycles. Also, when based on geometric, electronic and energetic aspects of aromaticity, a 3[n]CFU with a specific n is more strongly Baird-aromatic than the analogous 3[n]CPP while the magnetic indices tell the opposite. To construct large T1 state Baird-aromatic [n]CM's, the design should be such that the T1 state Baird aromaticity of the macrocyclic perimeter dominates over a situation with local closed-shell Hückel aromaticity of one or a few monocycles and semilocalized triplet diradical character. Monomers with lower Hückel aromaticity in S0 than benzene (e.g., furan) that do not impose steric congestion are preferred. Structural confinement imposed by, e.g., methylene bridges is also an approach to larger Baird-aromatic macrocycles. Finally, by using the Zilberg-Haas description of T1 state aromaticity, we reveal the analogy to the Hückel aromaticity of the corresponding closed-shell dications yet observe stronger Hückel aromaticity in the macrocyclic dications than Baird aromaticity in the T1 states of the neutral macrocycles. © 2021 The Authors.

  • 6.
    Ayub, Rabia
    et al.
    Uppsala University, Sweden.
    Jorner, K.
    Ottosson, H.
    The silacyclobutene ring: An indicator of triplet state Baird-aromaticity2017In: Inorganics, ISSN 2304-6740, Vol. 5, no 4, article id 91Article in journal (Refereed)
    Abstract [en]

    Baird's rule tells that the electron counts for aromaticity and antiaromaticity in the first ππ* triplet and singlet excited states (T1 and S1) are opposite to those in the ground state (S0). Our hypothesis is that a silacyclobutene (SCB) ring fused with a [4n]annulene will remain closed in the T1 state so as to retain T1 aromaticity of the annulene while it will ring-open when fused to a [4n + 2]annulene in order to alleviate T1 antiaromaticity. This feature should allow the SCB ring to function as an indicator for triplet state aromaticity. Quantum chemical calculations of energy and (anti)aromaticity changes along the reaction paths in the T1 state support our hypothesis. The SCB ring should indicate T1 aromaticity of [4n]annulenes by being photoinert except when fused to cyclobutadiene, where it ring-opens due to ring-strain relief. © 2017 by the authors.

  • 7.
    Ayub, Rabia
    et al.
    Uppsala University, Sweden.
    Papadakis, R.
    Jorner, K.
    Zietz, B.
    Ottosson, H.
    Cyclopropyl Group: An Excited-State Aromaticity Indicator?2017In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 55, p. 13684-13695Article in journal (Refereed)
    Abstract [en]

    The cyclopropyl (cPr) group, which is a well-known probe for detecting radical character at atoms to which it is connected, is tested as an indicator for aromaticity in the first ππ* triplet and singlet excited states (T1 and S1). Baird's rule says that the π-electron counts for aromaticity and antiaromaticity in the T1 and S1 states are opposite to Hückel's rule in the ground state (S0). Our hypothesis is that the cPr group, as a result of Baird's rule, will remain closed when attached to an excited-state aromatic ring, enabling it to be used as an indicator to distinguish excited-state aromatic rings from excited-state antiaromatic and nonaromatic rings. Quantum chemical calculations and photoreactivity experiments support our hypothesis; calculated aromaticity indices reveal that openings of cPr substituents on [4n]annulenes ruin the excited-state aromaticity in energetically unfavorable processes. Yet, polycyclic compounds influenced by excited-state aromaticity (e.g., biphenylene), as well as 4nπ-electron heterocycles with two or more heteroatoms represent limitations. 

  • 8.
    Babi, Mouhanad
    et al.
    McMaster University, Canada.
    Palermo, Anthony
    University of Toronto, Canada.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Fatona, Ayodele
    McMaster University, Canada.
    Jarvis, Victoria
    McMaster Analytical X-ray Diffraction Facility, Canada.
    Nayak, Akanksha
    McMaster University, Canada.
    Cranston, Emily
    University of British Colombia, USA.
    Moran-Mirabal, Jose
    McMaster University, Canada.
    Visualization of nanostructural dislocations in microcrystalline cellulose fibrils through super-resolution fluorescence microscopy2021In: Microscopy and Microanalysis, ISSN 1431-9276, E-ISSN 1435-8115, Vol. 27, no S1, p. 854-Article in journal (Refereed)
  • 9. Bergenstråhle-Wohlert, M.
    et al.
    Berglund, L.A.
    Brady, J.W.
    Larsson, P.T.
    RISE, Innventia.
    Westlund, P.-O.
    Wohlert, J.
    Concentration enrichment of urea at cellulose surfaces: Results from molecular dynamics simulations and NMR spectroscopy2012In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, no 1, p. 1-12Article in journal (Refereed)
  • 10. Bergstrm, E.M.
    et al.
    Salmen, L.
    RISE, Innventia.
    Kochumalayil, J.
    Berglund, L.
    Plasticized xyloglucan for improved toughness: Thermal and mechanical behaviour2012In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, no 4, p. 2532-2537Article in journal (Refereed)
  • 11.
    Björklund Jansson, Marianne
    et al.
    RISE, Innventia.
    Nilvebrant, N. -O
    Wood Extractives2009In: Wood Chemistry and Wood Biotechnology, Walter de Gruyter, 2009, p. 147-171Chapter in book (Refereed)
  • 12.
    Brodin, Ida
    et al.
    RISE, Innventia.
    Ernstsson, Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Gellerstedt, Göran
    RISE, Innventia.
    Sjöholm, Elisabeth
    RISE, Innventia.
    Oxidative stabilisation of kraft lignin for carbon fibre production2012In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, no 2, p. 141-147Article in journal (Refereed)
    Abstract [en]

    With the aim of investigating kraft lignin as a raw material for carbon fibre production, different lignins have been stabilised in air at conditions varied according to a full factorial experimental design. The lignins under examination were purified kraft lignin powders originating from birch, spruce/pine and Eucalyptus globules, as well as lignin fibres originating from birch with 5 poly(ethylene oxide) (PEO) added as a plasticiser. The influence of temperature, time and heating rate on yield and glass-transition temperature (Tg) was investigated. The highest yield was achieved after stabilisation at 280°C during 2h with a heating rate of 0.2°C min -1. The Tg of all lignin powders was increased when stabilisation occurred under harsher conditions. X-ray photoelectron spectroscopy analysis (XPS) of both the outer surface and the cleaved cross-section of individual lignin/PEO fibres showed a clear gradient in the degree of chemical modification, with the major change occurring on the surface resulting in the appearance of a skin-core structure after stabilisation. The behaviour of the lignin fibres during stabilisation is similar to that of pitch-based fibres, indicating good possibilities for lignin as raw material for carbon fibre production.

  • 13.
    Burke, Anthony
    et al.
    University of Evora, Romania.
    Federsel, Hans-Jürgen
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Hermann, Gesine
    University of Evora, Romania.
    Recent Advances in Asymmetric Hydrogenation Catalysis Utilizing Spiro and Other Rigid C-Stereogenic Phosphine Ligands2022In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 87, no 4, p. 1898-1924Article in journal (Refereed)
    Abstract [en]

    Transition-metal-catalyzed asymmetric reactions have been a powerful tool in organic synthesis for many years. The design of chiral ligands with the right configuration is fundamental to induce high regio- and stereoselectivity to catalytic reactions and to achieve high turnover numbers and high yields. A challenge is the control of prochiral centers with similar electronic properties in a similar steric environment within the same molecule. Over the last 10 years, a range of novel rigid C-stereogenic chiral phosphine ligands has been developed and successfully applied in various types of asymmetric transformations. Many of these ligands are of a di-, tri-, or multidentate nature. The purpose of this Perspective is to highlight recent synthetic achievements (since 2010) with spiro-phosphines and other rigid phosphines and discuss some mechanistic aspects of the catalytic reactions. 

  • 14.
    Carrick, Cristopher
    et al.
    KTH Royal Institute of Technology, Sweden.
    Ruda, Marcus C.
    SweTree Technologies AB, Sweden.
    Pettersson, Bert
    KTH Royal Institute of Technology, Sweden.
    Larsson, Per Tomas
    RISE, Innventia. Wallenberg Wood Science Centre, Sweden.
    Wågberg, Lars Göran
    Wallenberg Wood Science Centre, Sweden.
    Hollow cellulose capsules from CO2 saturated cellulose solutions: Their preparation and characterization2013In: RSC Advances, ISSN  2046-2069, no 7, p. 2462-2469Article in journal (Refereed)
    Abstract [en]

    A new material consisting of mm-sized hollow cellulose spheres, for biomedical applications or for the preparation of low weight porous materials has been prepared by a unique solution precipitation (SP) method. The technique is based on three separate steps. In the first step, high molecular mass, non-modified cellulose is dissolved in a suitable solvent. This cellulose solution is then saturated with a suitable gas (CO2 or N2 in the present work) and finally this gas-saturated solution is drop-wise added to a water reservoir. In this step, the cellulose is precipitated and a gas bubble is nucleated in the center of the cellulose sphere. When stored in water, the hollow center is filled with water, indicating that the capsule wall is porous in nature. This was also supported by BET-area measurements as well as by high resolution SEM-images of broken capsule walls. The internal void volume of a capsule was about 5 μl and the wall volume was about 8 μl. It was also established that the properties of the cellulose capsules, i.e. wall and void volume, the specific surface area, the average pore size of the capsule wall, the wall density, and the compressive load capacity could be tuned by the choice of cellulose concentration in the solution before precipitation. The capsule wall volume and void volume were also affected by the choice of gas, the gas pressure and the gas dissolution time during the gas saturation step. The response of the cellulose wall of the prepared capsules to changes in pH and ion concentration in the surrounding solution was also investigated. The swelling-shrinking behavior was further investigated by introducing more charges to the capsule wall, via carboxymethylation of the cellulose. This was achieved by using carboxymethylated cellulose which increased the swelling-shrinking effect. The results show a typical polyelectrolyte gel behavior of the capsule wall and the wet modulus of the cellulose wall was determined to be between 0.09-0.2 MPa depending on the charge of the cellulose in the capsule wall. Furthermore, the freeze dried cellulose spheres had a modulus of 1.9-7.4 MPa, depending on the cellulose concentration during the preparation of the spheres. These cellulose capsules are suitable both for the preparation of porous materials, where these larger spheres are joined together in 3D-shaped materials, and for controlled release where the interior of the capsules is filled with active substances and these substances are released by controlling the pores in the capsule walls.

  • 15.
    Chedid, Fadia
    et al.
    RISE, Innventia.
    Aldaeus, Fredrik
    RISE, Innventia.
    Jacobs, Anna
    RISE, Innventia.
    Lignin molecular mass determined using size-exclusion chromatography and MALDI-TOF mass spectrometry2014Conference paper (Refereed)
  • 16. Dammström, S.
    et al.
    Salmen, Lennart
    RISE, STFI-Packforsk.
    Gatenholm, P.
    On the interactions between cellulose and xylan, a biomimetic simulation of the hardwood cell wall2009In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 4, no 1, p. 3-14Article in journal (Refereed)
    Abstract [en]

    The plant cell wall exhibits a hierarchical structure, in which the organization of the constituents on different levels strongly affects the mechanical properties and the performance of the material. In this work, the interactions between cellulose and xylan in a model system consisting of a bacterial cellulose/glucuronoxylan (extracted from aspen, Populus tremula) have been studied and compared to that of a delignified aspen fiber material. The properties of the materials were analyzed using Dynamical Mechanical Analysis (DMA) with moisture scans together with dynamic Infra Red -spectroscopy at dry and humid conditions. The results showed that strong interactions existed between the cellulose and the xylan in the aspen holocellulose. The same kinds of interactions were seen in a water-extracted bacterial cellulose/xylan composite, while unextracted material showed the presence of xylan not interacting with the cellulose. Based on these findings for the model system, it was suggested that there is in hardwood one fraction of xylan that is strongly associated with the cellulose, taking a similar role as glucomannan in softwood.

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  • 17.
    Dedic, D.
    et al.
    RISE, Innventia.
    Iversen, T.
    RISE, Innventia.
    Sandberg, T.
    Ek, M.
    Chemical analysis of wood extractives and lignin in the oak wood of the 380 year old Swedish warship vasa2011Conference paper (Refereed)
  • 18.
    Fonseca, Daniela
    et al.
    University of Evora, Portugal.
    Amorim, Ana
    Chiratecnics, Portugal; University of Evora, Portugal.
    Carreiro, Elisabete
    University of Evora, Portugal.
    Ramalho, Joao
    University of Evora, Portugal.
    Hermann, Gesine
    Chiratecnics, LDA, Portugal; University of Evora, Portugal.
    Federsel, Hans-Jürgen
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Duarte, Ana Rita
    Universidade Nova de Lisboa, Portugal; University of Coimbra, Portugal.
    Burke, Anthony
    University of Evora, Portugal.
    Sustainable OrganoCatalyzed Enantioselective Catalytic Michael Additions in Betaine derived Deep Eutectic Solvents2023In: SynOpen, ISSN 2509-9396Article in journal (Refereed)
    Abstract [en]

    The catalyst cinchonidine-squaramide was immobilized within three different deep eutectic solvents (DES): (Betaine: D-Sorbitol: Water), (Betaine: D-Xylitol: Water) and (Betaine: D-Mannitol: Water) and evaluated in a well-known asymmetric Michael addition. These reactions provided excellent yields (up to 99%) and enantioselectivities (up to 98%) using only 1 mol% of catalyst. It was also possible to achieve 9 cycles in reactions with DES (Betaine: D-Sorbitol: Water), proving the high recyclability of this system. In the reactions realized with only 0.5 mol% of catalyst, it was possible to achieve 5 cycles and the products were obtained with high yields (up to 95%) and excellent enantioselectivities (up to 94%), using DES (Betaine: D-Sorbitol: Water)..

  • 19.
    Garg, Neeraj
    Uppsala University, Sweden.
    Chemoselective Probe Containing a Unique Bioorthogonal Cleavage Site for Investigation of Gut Microbiota Metabolism2018In: Angewandte Chemie, ISSN n2:1433-7851, Vol. 57, no 42, p. 13805-13809Article in journal (Refereed)
  • 20.
    Garg, Neeraj
    Uppsala University, Sweden.
    Highly Sensitive MassSpectrometric Analysis of Metabolic Ketones and Aldehydes in Human FecalSamples2019In: Chemical Communications, ISSN 1359-7345, Vol. 55, no 62, p. 9080-9083Article in journal (Refereed)
  • 21.
    Garg, Neeraj
    Uppsala University, Sweden.
    New enzymatic and massspectrometric methodology for the selective investigation of gutmicrobiota-derived metabolites2018In: Chem. Sci., ISSN 2456-706X, Vol. 9, no 29, p. 6233-6239Article in journal (Refereed)
  • 22.
    Garg, Neeraj
    Uppsala University, Sweden.
    Structural elucidation of major selective androgen receptor modulator (SARM) metabolites for doping control2018In: Org. Biomol. Chem., Vol. 29, p. 698-702, article id 10.1039/C7OB03030DArticle in journal (Other academic)
  • 23.
    Gebremeskel, Getachew Gizaw
    et al.
    RISE, Innventia.
    Aldaeus, Fredrik
    RISE, Innventia.
    Determination of lignin content in kraft black liquors by capillary zone electrophoresis (CZE)2013In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, no 8, p. 887-890Article in journal (Refereed)
    Abstract [en]

    Capillary zone electrophoresis (CZE) in an alkaline glycine buffer is suggested for the quantification of lignin content in black liquors (BL). The method was first tested by an external calibration with LignoBoost lignins. Then, the lignin content in BL was determined by means of a multivariate calibration with the application of a standard normal variate filter and partial least squares approach based on five principal components. The results are in agreement with those obtained by sulfuric acid lignin precipitation combined with ultraviolet measurement of the lignin in solution. The advantage of the CZE method is its independence from the knowledge of the exact absorptivity coefficient, which is needed for direct spectrophotometric lignin determination. Moreover, interfering substances and degradation products could be recognized and excluded from lignin determination; thus, the selectivity was increased significantly.

  • 24.
    Gellerstedt, Göran L.F.
    et al.
    RISE, Innventia.
    Tomani, Per E.
    RISE, Innventia.
    Axegård, Peter
    RISE, Innventia.
    Backlund, Birgit
    RISE, Innventia.
    Lignin recovery and lignin-based products2013In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, p. 180-210Article in journal (Refereed)
  • 25.
    Hua, Kai
    et al.
    Uppsala University, Sweden.
    Carlsson, Daniel O.
    Uppsala University, Sweden.
    Ålander, Eva M.
    RISE, Innventia.
    Lindström, Tom
    RISE, Innventia.
    Strömme, Maria
    RISE, Innventia.
    Mihranyan, Albert
    Uppsala University, Sweden.
    Ferraz, Natalia
    Uppsala University, Sweden.
    Translational study between structure and biological response of nanocellulose from wood and green algae2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 6, p. 2892-2903Article in journal (Refereed)
    Abstract [en]

    The influence of nanostructure on the cytocompatibility of cellulose films is analyzed providing insight into how physicochemical properties of surface modified microfibrillated cellulose (MFC) and Cladophora nanocellulose (CC) affect the materials cytocompatibility. CC is modified through TEMPO-mediated oxidation and glycidyltrimethylammonium chloride (EPTMAC) condensation to obtain anionic and cationic nanocellulose samples respectively, while anionic and cationic MFC samples are obtained by carboxymethylation and EPTMAC condensation respectively. Films of unmodified, anionic and cationic MFC and CC are prepared by vacuum filtration and characterized in terms of specific surface area, pore size distribution, degree of crystallinity, surface charge and water content. Human dermal fibroblasts are exposed to culture medium extracts of the films in an indirect contact cytotoxicity test. Moreover, cell adhesion and viability are evaluated in a direct contact assay and the effects of the physicochemical properties on cell behavior are discussed. In the indirect cytotoxicity test no toxic leachables are detected, evidencing that the CC and MFC materials are non-cytotoxic, independently of the chemical treatment that they have been subjected to. The direct contact tests show that carboxymethylated-MFC presents a more cytocompatible profile than unmodified and trimethylammonium-MFC. TEMPO-CC promotes fibroblast adhesion and presents cell viability comparable to the results obtained with the tissue culture material Thermanox. We hypothesize that the distinct aligned nanofiber structure present in the TEMPO-CC films is responsible for the improved cell adhesion. Thus, by controlling the surface properties of cellulose nanofibers, such as chemistry, charge, and orientation, cell adhesion properties can be promoted.

  • 26.
    Håkansson, Karl M.O.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Fall, Andreas
    KTH Royal Institute of Technology, Sweden.
    Lundell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Yu, S.
    DESY, Germany.
    Krywka, Christina A.
    University of Kiel, Germany; Helmholtz-Zentrum Geesthacht, Germany.
    Roth, Stephan Volkher
    University of Kiel, Germany.
    Santoro, Gonzalo
    DESY, Germany.
    Kvick, Mathias
    KTH Royal Institute of Technology, Sweden.
    Prahl Wittberg, Lisa
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars Göran
    KTH Royal Institute of Technology, Sweden.
    Söderberg, L. Daniel
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments2014In: Nature Communications, E-ISSN 2041-1723, Vol. 5, article id 4018Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibrils can be obtained from trees and have considerable potential as a building block for biobased materials. In order to achieve good properties of these materials, the nanostructure must be controlled. Here we present a process combining hydrodynamic alignment with a dispersion-gel transition that produces homogeneous and smooth filaments from a low-concentration dispersion of cellulose nanofibrils in water. The preferential fibril orientation along the filament direction can be controlled by the process parameters. The specific ultimate strength is considerably higher than previously reported filaments made of cellulose nanofibrils. The strength is even in line with the strongest cellulose pulp fibres extracted from wood with the same degree of fibril alignment. Successful nanoscale alignment before gelation demands a proper separation of the timescales involved. Somewhat surprisingly, the device must not be too small if this is to be achieved.

  • 27.
    Jacobs, Anna
    et al.
    RISE, Innventia. RISE - Research Institutes of Sweden (2017-2019).
    Aldaeus, Fredrik
    RISE, Innventia.
    Lignin and hemicellulose characterization for the biorefinery2014Conference paper (Refereed)
  • 28.
    Jacobs, Anna
    et al.
    RISE, Innventia.
    Aldaeus, Fredrik
    RISE, Innventia.
    Chedid, Fadia
    RISE, Innventia.
    Molecular mass distribution of lignin from black liquor: methods comparison2014Conference paper (Refereed)
  • 29.
    Johansson, Eva
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Malik, Ali Hafeez
    SLU Swedish University of Agricultural Sciences, Sweden; Syngenta Seeds AB, Sweden.
    Hussain, Abrar
    SLU Swedish University of Agricultural Sciences, Sweden; COMSATS Institute of Information Technology, Pakistan.
    Rasheed, Faiza
    SLU Swedish University of Agricultural Sciences, Sweden.
    Newson, William R.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Plivelic, Tomas S.
    Lund University, Sweden.
    Hedenqvist, Mikael Stefan
    KTH Royal Institute of Technology, Sweden.
    Gällstedt, Mikael
    RISE, Innventia.
    Kuktaite, Ramune
    SLU Swedish University of Agricultural Sciences, Sweden.
    Wheat gluten polymer structures: The impact of genotype environment and processing on their functionality in various applications2013In: Cereal Chemistry, ISSN 0009-0352, E-ISSN 1943-3638, Vol. 90, no 4, p. 367-376Article in journal (Refereed)
    Abstract [en]

    For a number of applications, gluten protein polymer structures are of the highest importance in determining end-use properties. The present article focuses on gluten protein structures in the wheat grain, genotype- and environment-related changes, protein structures in various applications, and their impact on quality. Protein structures in mature wheat grain or flour are strongly related to end-use properties, although influenced by genetic and environment interactions. Nitrogen availability during wheat development and genetically determined plant development rhythm are the most important parameters determining the gluten protein polymer structure, although temperature during plant development interacts with the impact of the mentioned parameters. Glutenin subunits are the main proteins incorporated in the gluten protein polymer in extracted wheat flour. During dough mixing, gliadins are also incorporated through disulfide-sulfhydryl exchange reactions. Gluten protein polymer size and complexity in the mature grain and changes during dough formation are important for breadmaking quality. When using the gluten proteins to produce plastics, additional proteins are incorporated in the polymer through disulfide-sulfhydryl exchange, sulfhydryl oxidation, β-eliminations with lanthionine formation, and isopeptide formation. In promising materials, the protein polymer structure is changed toward β-sheet structures of both intermolecular and extended type and a hexagonal close-packed structure is found. Increased understanding of gluten protein polymer structures is extremely important to improve functionality and end-use quality of wheat- and gluten-based products.

  • 30. Jorner, K.
    et al.
    Feixas, F.
    Ayub, Rabia
    Uppsala University, Sweden.
    Lindh, R.
    Solà, M.
    Ottosson, H.
    Analysis of a Compound Class with Triplet States Stabilized by Potentially Baird Aromatic [10]Annulenyl Dicationic Rings2016In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, no 8, p. 2793-2800Article in journal (Refereed)
    Abstract [en]

    The low-lying triplet state of a recently published compound (TMTQ) was analyzed quantum chemically in light of suggestions that it is influenced by Baird aromaticity. Two mesomeric structures describe this state: 1) a zwitterionic Baird aromatic structure with a triplet diradical 8π-electron methano[10]annulene (M10A) dicationic ring and 2) a Hückel aromatic with a neutral closed-shell 10π-electron ring. According to charge and spin density distributions, the Hückel aromatic structure dominates the triplet state (the Baird aromatic contributes at most 12 %), and separation of the aromatic fluctuation index (FLU) into α and β electron contributions emphasizes this finding. The small singlet-triplet energy gap is due to Hückel aromaticity of the M10A ring, clarified by comparison to the smaller analogues of TMTQ. Yet, TMTQ and its analogues are Hückel-Baird hybrids allowing for tuning between closed-shell 4n+2 Hückel aromaticity and open-shell 4n Baird aromaticity. 

  • 31.
    Junka, Karoliina
    et al.
    Aalto University, Finland.
    Filpponen, Ilari
    Aalto University, Finland.
    Lindström, Tom
    RISE, Innventia.
    Laine, Janne
    Aalto University, Finland.
    Titrimetric methods for the determination of surface and total charge of functionalized nanofibrillated/microfibrillated cellulose (NFC/MFC)2013In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20, no 6, p. 2887-2895Article in journal (Refereed)
    Abstract [en]

    Total and surface charge of three different carboxymethylated nanofibrillated/microfibrillated cellulose (NFC/MFC) samples were investigated by using titrimetric methods (conductometric and polyelectrolyte (PE) titrations). Conductometric titration was found to be suitable method for the NFC total charge measurements when the back titration with HCl was applied. Surface charge measurements of NFC/MFC were conducted by using both indirect and direct PE titrations. The direct PE titration was found to be a more suitable method for the surface charge determination of NFC/MFC whereas the indirect PE titration produced too high surface charge values. This is presumably due to kinetically locked polyelectrolyte conformations on the NFC/MFC surfaces or entrapment of residual polymer after adsorption onto the NFC/MFC gel network. Finally, NFC was propargyl-functionalized and the changes in surface and total charge were successfully monitored and compared to those of propargyl-functionalized pulp. A good correlation between the titrimetric methods and elemental analysis was observed. 

  • 32.
    Karalė, Kristina
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development. Karolinska Institute, Sweden.
    Bollmark, Martin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Stulz, Rouven
    Karolinska Institute, Sweden; AstraZeneca, Sweden.
    Honcharenko, Dmytro
    Karolinska Institute, Sweden.
    Tedebark, Ulf
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Strömberg, Roger
    Karolinska Institute, Sweden.
    A study on synthesis and upscaling of 2′-o-aecm-5-methyl pyrimidine phosphoramidites for oligonucleotide synthesis2021In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 22, article id 6927Article in journal (Refereed)
    Abstract [en]

    2′-O-(N-(Aminoethyl)carbamoyl)methyl-modified 5-methyluridine (AECM-MeU) and 5-methylcytidine (AECM-MeC) phosphoramidites are reported for the first time and prepared in multigram quantities. The syntheses of AECM-MeU and AECM-MeC nucleosides are designed for larger scales (approx. 20 g up until phosphoramidite preparation steps) using low-cost reagents and minimizing chromatographic purifications. Several steps were screened for best conditions, focusing on the most crucial steps such as N3 and/or 2′-OH alkylations, which were improved for larger scale synthesis using phase transfer catalysis (PTC). Moreover, the need of chromatographic purifications was substantially reduced by employing one-pot synthesis and improved work-up strategies. © 2021 by the authors. 

  • 33.
    Krochak, Paul
    et al.
    RISE, Innventia.
    Holm, Rickard
    RISE, Innventia.
    Söderberg, Daniel
    RISE, Innventia.
    Drag reduction characteristics of micro-fibrillated cellulose suspensions2011Conference paper (Refereed)
  • 34.
    Kulasinski, Karol
    et al.
    ETH Zurich, Switzerland; Empa Swiss Federal Laboratories for Materials Science and Technology, Switzerland.
    Salmén, Lennart
    RISE, Innventia.
    Derome, Dominique
    Empa Swiss Federal Laboratories for Materials Science and Technology, Switzerland.
    Carmeliet, Jan
    ETH Zurich, Switzerland; Empa Swiss Federal Laboratories for Materials Science and Technology, Switzerland.
    Moisture adsorption of glucomannan and xylan hemicelluloses2016In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 3, p. 1629-1637Article in journal (Refereed)
    Abstract [en]

    Wood and wood materials are highly sensitive to moisture in the environment. To a large extent this relates to the hygroscopicity of wood hemicelluloses. In order to increase our understanding of the effects of moisture sorption of the major wood hemicelluloses, glucomannan and xylan, model experiments using films of amorphous konjak glucomannan and rye arabinoxylan were conducted. Moisture-induced expansion and stiffness softening were characterized using dynamic mechanical testing. Both hemicelluloses showed a threshold around 5 % of moisture content above which swelling increased whereas the modulus decreased by more than 70 %. FTIR spectra, using H2O and D2O, indicated that even at high RH about 15 % of the hydroxyl groups were not accessible to hydrogen exchange by D2O. For xylan both hydroxyl groups were found to exchange in the same manner while for the glucomannan the O(6)H group seemed to be the most accessible.

  • 35.
    Larsson, Per Tomas
    RISE, Innventia.
    Solid state NMR as a tool for measuring pore sizes in water swollen cellulose fibre walls2013Conference paper (Refereed)
  • 36.
    Larsson, Per Tomas
    et al.
    RISE, Innventia.
    Svensson, Anna
    Wågberg, Lars
    Solid state NMR as a tool for measuring pore sizes in water swollen cellulose fibre walls2012Conference paper (Refereed)
  • 37.
    Lee, Taegyo
    et al.
    University of California, USA.
    Wilson, Tyler W.
    University of California, USA.
    Berg, Robert
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Process Development, Katalys.
    Ryberg, Per
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Hartwig, John F.
    University of California, USA.
    Rhodium-Catalyzed Enantioselective Silylation of Arene C–H Bonds: Desymmetrization of Diarylmethanols2015In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, no 21, p. 6742-6745Article in journal (Refereed)
    Abstract [en]

    We report a Rh-catalyzed, enantioselective silylation of arene C–H bonds directed by a (hydrido)silyl group. (Hydrido)silyl ethers that are formed in situ by hydrosilylation of benzophenone or its derivatives undergo asymmetric C–H silylation in high yield with excellent enantioselectivity in the presence of [Rh(cod)Cl]2 and a chiral bisphosphine ligand. The stereoselectivity of this process also allows enantioenriched diarylmethanols to react with site selectivity at one aryl group over the other. Enantioenriched benzoxasiloles from the silylation process undergo a range of transformations to form C–C, C–O, C–I, or C–Br bonds.

  • 38.
    Lindfors, Eva-Lisa
    et al.
    RISE, STFI-Packforsk.
    Lindström, Mikael
    RISE, STFI-Packforsk.
    Iversen, Tommy
    RISE, STFI-Packforsk.
    Polysaccharide degradation in waterlogged oak wood from the ancient warship Vasa2008In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 62, no 1, p. 57-63Article in journal (Refereed)
    Abstract [en]

    A rather extensive degradation of cellulose and hemicelluloses was found in waterlogged oak wood samples from the ancient warship Vasa by size exclusion chromatography with the solvent system lithium chloride/N,N-dimethylacetamide (LiCl/DMAc). The degradation has mainly occurred after salvage of the wreck, probably as a consequence of keeping iron contaminated wood in contact with air. The most likely explanation is Fenton type of reactions degrading the wood polymers and oxidising reduced sulphur forms to sulphuric acid. An increased degradation rate of the Vasa wood can be anticipated in the future if the sulphuric acid cannot be neutralised and the oxidative reactions cannot be quenched.

  • 39.
    Lindh, Erik L.
    et al.
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Bergenstråhle-Wohlert, Malin
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Terenzi, Camilla
    KTH Royal Institute of Technology, Sweden.
    Salmen, Lennart
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Furo, István
    KTH Royal Institute of Technology, Sweden.
    Non-exchanging hydroxyl groups on the surface of cellulose fibrils: The role of interaction with water2016In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 434, p. 136-142Article in journal (Refereed)
    Abstract [en]

    The interaction of water with cellulose stages many unresolved questions. Here 2H MAS NMR and IR spectra recorded under carefully selected conditions in 1H-2H exchanged, and re-exchanged, cellulose samples are presented. It is shown here, by a quantitative and robust approach, that only two of the three available hydroxyl groups on the surface of cellulose fibrils are exchanging their hydrogen with the surrounding water molecules. This finding is additionally verified and explained by MD simulations which demonstrate that the 1HO(2) and 1HO(6) hydroxyl groups of the constituting glucose units act as hydrogen-bond donors to water, while the 1HO(3) groups behave exclusively as hydrogen-bond acceptors from water and donate hydrogen to their intra-chain neighbors O(5). We conclude that such a behavior makes the latter hydroxyl group unreactive to hydrogen exchange with water.

  • 40.
    Martinez-Crespiera, Sandra
    et al.
    Leitat Technological Center, Spain.
    Pepió-Tàrrega, Belen
    Leitat Technological Center, Spain.
    González-Gil, Rosa
    Leitat Technological Center, Spain.
    Cecilia-Morillo, Francisci
    Leitat Technological Center, Spain.
    Palmer, Javier
    Leitat Technological Center, Spain.
    Escobar, Ana
    Leitat Technological Center, Spain.
    Beneitez-Álvarez, Sirio
    Leitat Technological Center, Spain.
    Abitbol, Tiffany
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Fall, Andreas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Aulin, Christian
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Nevo, Yuval
    Melodea Ltd, Israel.
    Beni, Valerio
    RISE Research Institutes of Sweden, Digital Systems, Smart Hardware.
    Tolin, Enrico
    IMST GmbH, Germany.
    Bahr, Achim
    IMST GmbH, Germany.
    Use of Nanocellulose to Produce Water-Based Conductive Inks with Ag NPs for Printed Electronics2022In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 23, no 6, article id 2946Article in journal (Refereed)
    Abstract [en]

    The need for more sustainable printed electronics has emerged in the past years. Due to this, the use of nanocellulose (NC) extracted from cellulose has recently been demonstrated to provide interesting materials such as functional inks and transparent flexible films due to its properties. Its high specific surface area together with the high content of reactive hydroxyl groups provide a highly tailorable surface chemistry with applications in ink formulations as a stabilizing, capping, binding and templating agent. Moreover, NC mechanical, physical and thermal properties (high strength, low porosity and high thermal stability, respectively) provide an excellent alternative for the currently used plastic films. In this work, we present a process for the production of water-based conductive inks that uses NC both as a template for silver nanoparticles (Ag NPs) formation and as an ink additive for ink formulation. The new inks present an electrical conductivity up to 2 × 106 S/m, which is in the range of current commercially available conductive inks. Finally, the new Ag NP/NC-based conductive inks have been tested to fabricate NFC antennas by screen-printing onto NC-coated paper, demonstrating to be operative.

  • 41.
    Moodie, Lindon W. K.
    et al.
    UiT The Arctic University of Norway, Norway.
    Žužek, Monika C.
    University of Ljubljana, Slovenia.
    Frangež, Robert
    University of Ljubljana, Slovenia.
    Andersen, Jeanette H.
    UiT The Arctic University of Norway, Norway.
    Hansen, Espen
    UiT The Arctic University of Norway, Norway.
    Olsen, Elisabeth K.
    UiT The Arctic University of Norway, Norway.
    Cergolj, Marija
    University of Ljubljana, Slovenia; University of Rijeka, Croatia.
    Sepčić, Kristina
    University of Ljubljana, Slovenia.
    Hansen, Kine Ø
    UiT The Arctic University of Norway, Norway.
    Svenson, Johan
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik. UiT The Arctic University of Norway, Norway.
    Synthetic analogs of stryphnusin isolated from the marine sponge: Stryphnus fortis inhibit acetylcholinesterase with no effect on muscle function or neuromuscular transmission2016In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 14, no 47, p. 11220-11229Article in journal (Refereed)
    Abstract [en]

    The marine secondary metabolite stryphnusin (1) was isolated from the boreal sponge Stryphnus fortis, collected off the Norwegian coast. Given its resemblance to other natural acetylcholinesterase antagonists, it was evaluated against electric eel acetylcholinesterase and displayed inhibitory activity. A library of twelve synthetic phenethylamine analogs, 2a-7a and 2b-7b, containing tertiary and quaternary amines respectively were synthesized to investigate the individual structural contributions to the activity. Compound 7b was the strongest competitive inhibitor of both acetylcholinesterase and butyrylcholinesterase with IC50 values of 57 and 20 μM, respectively. This inhibitory activity is one order of magnitude higher than the positive control physostigmine, and is comparable with several other marine acetylcholinesterase inhibitors. The physiological effect of compound 7b on muscle function and neuromuscular transmission was studied and revealed a selective mode of action at the investigated concentration. This data is of importance as the interference of therapeutic acetylcholinesterase inhibitors with neuromuscular transmission can be problematic and lead to unwanted side effects. The current findings also provide additional insights into the structure-activity relationship of both natural and synthetic acetylcholinesterase inhibitors.

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  • 42.
    Nilsson, Helena
    et al.
    RISE, STFI-Packforsk.
    Olsson, Ann
    RISE, STFI-Packforsk.
    Lindström, Mikael
    RISE, STFI-Packforsk.
    Iversen, Tommy
    RISE, STFI-Packforsk.
    Birch bark as a source for fine chemicals2008In: 2008 Nordic Wood Biorefinery Conference - Proceedings: NWBC 2008, 2008, Vol. 274, no 1, p. 125-128Conference paper (Refereed)
    Abstract [en]

    In this study we report polycondensation and co-polymerization of cis-9,10-epoxy-18-hydroxyoctadecanoic acid (1) isolated from birch outer bark using immobilized Candida antarctica lipase B (Novozyme 435) as catalyst to give epoxy activated straight chain polyesters and cyclic macromonomers.

  • 43.
    Olsen, Elisabeth K.
    et al.
    UiT The Arctic University of Norway, Norway.
    Hansen, Espen
    UiT The Arctic University of Norway, Norway.
    Moodie, Lindon W. K.
    University of Umeå, Sweden.
    Isaksson, Johan
    UiT The Arctic University of Norway, Norway.
    Sepčić, Kristina
    University of Ljubljana, Slovenia.
    Cergolj, Marija
    University of Ljubljana, Slovenia; University of Rijeka, Croatia.
    Svenson, Johan
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik.
    Andersen, Jeanette H.
    UiT The Arctic University of Norway, Norway.
    Marine AChE inhibitors isolated from Geodia barretti: Natural compounds and their synthetic analogs2016In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 14, no 5, p. 1629-1640Article in journal (Refereed)
    Abstract [en]

    Barettin, 8,9-dihydrobarettin, bromoconicamin and a novel brominated marine indole were isolated from the boreal sponge Geodia barretti collected off the Norwegian coast. The compounds were evaluated as inhibitors of electric eel acetylcholinesterase. Barettin and 8,9-dihydrobarettin displayed significant inhibition of the enzyme, with inhibition constants (Ki) of 29 and 19 μM respectively towards acetylcholinesterase via a reversible noncompetitive mechanism. These activities are comparable to those of several other natural acetylcholinesterase inhibitors of marine origin. Bromoconicamin was less potent against acetylcholinesterase, and the novel compound was inactive. Based on the inhibitory activity, a library of 22 simplified synthetic analogs was designed and prepared to probe the role of the brominated indole, common to all the isolated compounds. From the structure-activity investigation it was shown that the brominated indole motif is not sufficient to generate a high acetylcholinesterase inhibitory activity, even when combined with natural cationic ligands for the acetylcholinesterase active site. The four natural compounds were also analysed for their butyrylcholinesterase inhibitory activity in addition and shown to display comparable activities. The study illustrates how both barettin and 8,9-dihydrobarettin display additional bioactivities which may help to explain their biological role in the producing organism. The findings also provide new insights into the structure-activity relationship of both natural and synthetic acetylcholinesterase inhibitors.

  • 44. Papadakis, R.
    et al.
    Li, H.
    Bergman, J.
    Lundstedt, A.
    Jorner, K.
    Ayub, Rabia
    Uppsala University, Sweden.
    Haldar, S.
    Jahn, B. O.
    Denisova, A.
    Zietz, B.
    Lindh, R.
    Sanyal, B.
    Grennberg, H.
    Leifer, K.
    Ottosson, H.
    Metal-free photochemical silylations and transfer hydrogenations of benzenoid hydrocarbons and graphene2016In: Nature Communications, E-ISSN 2041-1723, Vol. 7, article id 12962Article in journal (Refereed)
    Abstract [en]

    The first hydrogenation step of benzene, which is endergonic in the electronic ground state (S 0), becomes exergonic in the first triplet state (T 1). This is in line with Baird's rule, which tells that benzene is antiaromatic and destabilized in its T 1 state and also in its first singlet excited state (S 1), opposite to S 0, where it is aromatic and remarkably unreactive. Here we utilized this feature to show that benzene and several polycyclic aromatic hydrocarbons (PAHs) to various extents undergo metal-free photochemical (hydro)silylations and transfer-hydrogenations at mild conditions, with the highest yield for naphthalene (photosilylation: 21%). Quantum chemical computations reveal that T 1-state benzene is excellent at H-atom abstraction, while cyclooctatetraene, aromatic in the T 1 and S 1 states according to Baird's rule, is unreactive. Remarkably, also CVD-graphene on SiO 2 is efficiently transfer-photohydrogenated using formic acid/water mixtures together with white light or solar irradiation under metal-free conditions. © The Author(s) 2016.

  • 45.
    Penttilä, Paavo A.
    et al.
    University of Helsinki, Finland.
    Varnai, Aniko
    University of Helsinki, Finland.
    Pere, Jaakko
    VTT Technical Research Centre of Finland, Finland.
    Tammelin, Tekla
    RISE, Innventia.
    Salmen, Lennart
    RISE, Innventia.
    Siika-Aho, Matti
    VTT Technical Research Centre of Finland, Finland.
    Viikari, Liisa
    University of Helsinki, Finland.
    Serimaa, Ritva E.
    University of Helsinki, Finland.
    Xylan as limiting factor in enzymatic hydrolysis of nanocellulose2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 129, p. 135-141Article in journal (Refereed)
    Abstract [en]

    The role of xylan as a limiting factor in the enzymatic hydrolysis of cellulose was studied by hydrolysing nanocellulose samples prepared by mechanical fibrillation of birch pulp with varying xylan content. Analyzing the nanocelluloses and their hydrolysis residues with dynamic FT-IR spectroscopy revealed that a certain fraction of xylan remained tightly attached to cellulose fibrils despite partial hydrolysis of xylan with xylanase prior to pulp fibrillation and that this fraction remained in the structure during the hydrolysis of nanocellulose with cellulase mixture as well. Thus, a loosely bound fraction of xylan was predicted to have been more likely removed by purified xylanase. The presence of loosely bound xylan seemed to limit the hydrolysis of crystalline cellulose, indicated by an increase in cellulose crystallinity and by preserved crystal width measured with wide-angle X-ray scattering. Removing loosely bound xylan led to a proportional hydrolysis of xylan and cellulose with the cellulase mixture. 

  • 46.
    Perez, Oswaldo
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development. University of Iceland, Iceland.
    Schipper, Nicolaas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Bollmark, Martin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Preparative Synthesis of an RP-Guanosine-3′,5′-Cyclic Phosphorothioate Analogue, a Drug Candidate for the Treatment of Retinal Degenerations2021In: Organic Process Research & Development, ISSN 1083-6160, E-ISSN 1520-586X, Vol. 25, no 11, p. 2453-Article in journal (Refereed)
    Abstract [en]

    Cyclic guanosine monophosphorothioate analogue 1a is currently showing potential as a drug for the treatment of inherited retinal neurodegenerations. To support ongoing preclinical and clinical work, we have developed a diastereoselective synthesis via cyclization and sulfurization of the nucleoside 5′-H-phosphonate monoester, which affords the desired RP-3′,5′-cyclic phosphorothioate in 9:1 ratio to the undesired SP-diastereomer. This route was made viable as a result of the silyl protection sequence used, which achieved >80% selectivity for 2′,5′-hydroxyls over 3′,5′-hydroxyls. Finally, the chromatography-free process allowed for a scale-up, as intermediates and the final product were isolated by crystallization to give 125 g of 1a (13.8% total yield) with over 99.9% HPLC purity. © 2021 The Authors.

  • 47.
    Persson, Johanna
    et al.
    RISE, Innventia.
    Dahlman, Olof B.
    RISE, Innventia.
    Albertsson, Ann Christine
    KTH Royal Institute of Technology, Sweden.
    Birch xylan grafted with pla branches of predictable length2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, no 3, p. 3640-3655Article in journal (Refereed)
    Abstract [en]

    Birch xylan (4-O-methylglucuronoxylan) isolated from a kraft cooking liquor was delignified and grafted with polylactide of predictable branch length. This graft copolymerization resulted in very high total yields, greater than 90%, and with less than 10% polylactide homopolymer byproducts. Mild reaction conditions (40°C, 5 to 120 minutes) were used, which was believed to limit transesterification reactions and thus make it possible to reach good predictability of the polylactide branch length. The thermal properties of the polylactide-grafted xylan depended on the branch length. Short branches resulted in fully amorphous materials with a glass transition temperature of about 48 to 55°C, whereas long polylactide branches resulted in semi-crystalline materials with melting points of about 130°C. Using mixtures of L-lactide and D/L-lactide in the monomer feed further altered the thermal properties. The degradation temperatures of the polylactide-grafted xylans were higher than that of the unmodified xylan, with degradation temperatures of about 300°C and 250°C, respectively. Tensile testing showed increased elongation at break with increasing branch length. The proposed method thus enables tailor-making of copolymers with specific thermal and mechanical properties.

  • 48.
    Persson, Johanna
    et al.
    RISE, Innventia.
    Dahlman, Olof B.
    RISE, Innventia.
    Albertsson, Ann Christine
    KTH Royal Institute of Technology, Sweden.
    Edlund, Ulrica
    KTH Royal Institute of Technology, Sweden.
    Modification of birch xylan by lactide-grafting2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 3, p. 518-524Article in journal (Refereed)
    Abstract [en]

    4-O-methylglucuronoxylan, isolated by ultrafiltration from a birch kraft cooking liquor, was delignified and subsequently modified by grafting lactide-chains onto the hydroxyl groups via ring opening polymerization with L-lactide. The structures and average molar masses of the lactide-grafted xylan polymers were characterised by NMR and SEC respectively. By varying the lactide-to-xylan feed ratio, graft polymers with different graft levels were synthesized. The degree of substitution of the hydroxyls in the xylan back-bone ranged from 0.7 to 1.7 with lactide side-chains having an average length of 1.2 to 2.5 lactide units. The side-chain length and degree of substitution influenced the hydrophobicity, thermal properties and tensile strength properties. A glass transition could be detected for lactide-grafted xylan polymers with lactide chains longer than 1.8 lactide units. Solution-cast thin films prepared from lactide-grafted xylans exhibited strong tensile strength and high modulus with decreasing strength and increasing elongation at break as the lactide chain length was increased.

  • 49. Raheel, A.
    et al.
    Imtiaz-Ud-Din,
    Iftikhar, S. H.
    Taj, M. B.
    Ayub, Rabia
    Stockholm University, Sweden.
    Zafar, A.
    Abbas, S.
    Al-Shakban, M.
    Synthesis, antimicrobial activity, urease inhibition and molecular docking studies of new proline linked thiourea derivatives2020In: Revue roumaine de chimie, ISSN 0035-3930, Vol. 65, no 9, p. 783-788Article in journal (Refereed)
    Abstract [en]

    A series of new thiourea based carboxylic acids (Ia-Ie) were synthesized and characterized by elemental analysis, FTIR and NMR (1H and 13C) spectroscopy. They were preliminary bioassayed for their antibacterial, anifungal and urease inhibition activities. Molecular docking simulations were carried out to determine the probable binding mode of the synthesized compounds. The bioassay results showed that some of titled compounds exhibited encouraging results. 

  • 50.
    Rezayati Charani, Pejman Rezayati
    et al.
    Behbahan Khatam Al Anbia University of Technology, Iran.
    Dehghani-Firouzabadi, Mohammadreza
    Gorgan University of Agricultural Sciences and Natural Resources, Iran.
    Afra, Elyas
    Gorgan University of Agricultural Sciences and Natural Resources, Iran.
    Blademo, Åsa
    RISE, Innventia.
    Naderi, Ali
    RISE, Innventia.
    Lindström, Tom
    KTH Royal Institute of Technology, Sweden.
    Production of microfibrillated cellulose from unbleached kraft pulp of Kenaf and Scotch Pine and its effect on the properties of hardwood kraft:: Microfibrillated cellulose paper2013In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20, no 5, p. 2559-2567Article in journal (Refereed)
    Abstract [en]

    This work investigated the effect of using Kenaf bast fibre kraft pulps compared to Scotch Pine kraft pulps for producing microfibrillated cellulose (MFC) and its employment for improving mechanical and physical properties of handsheets made from unbleached kraft hardwood pulp. It was shown that MFC based on Kenaf fibres can be produced at higher consistencies [>5 % (w/w)] compared to when Scotch Pine is employed [≈2 % (w/w)] as raw material. The possibility of using a higher consistency when processing Kenaf is beneficial for the processing in microfluidizers. The rheological properties of the products were shown to be consistent with what is known for MFC-based systems. The studies indicate that the mechanical properties of handsheets from unbleached kraft hardwood pulp can be improved by replacing part of the unbleached kraft hardwood pulp fibres with either unbleached kraft Kenaf pulp or unbleached Scotch Pine kraft pulp. However, the same levels of improvements were obtained when using only a small amount [≈6 % (w/w)] of MFC based on Kenaf or Scotch Pine, when introduced into the system either as a dry strength additive or by coating pre-made handsheets. Finally, it was shown that the incorporation of MFC in handsheets decreases the air-permeability; this effect became amplified when the MFC was applied as a coating onto the handsheets. 

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