Publications
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Cutajar, Michelle; Machado, Fabricio; Crucitti, Valentina Cuzzucoli; Braovac, Susan-Diana; Stockman, Robert A. & Howdle, Steven M.
[Show all 7 contributors for this article]
(2022).
Comparative hydrodynamic characterisation of two hydroxylated polymers based on α-pinene- or oleic acid-derived monomers for potential use as archaeological consolidants.
Scientific Reports.
12(1).
doi:
10.1038/s41598-022-21027-4.
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Abstract The Oseberg Viking ship burial is one of the most extensive collections of Viking wooden artefacts ever excavated in Norway. In the early twentieth century, many of these artefacts were treated with alum in order to preserve them, inadvertently leading to their current degraded state. It is therefore crucial to develop new bioinspired polymers which could be used to conserve these artefacts and prevent further disintegration. Two hydroxylated polymers were synthesised (TPA6 and TPA7), using α-pinene- and oleic acid-derived monomers functionalised with an acrylate moiety. Characterisation using biomolecular hydrodynamics (analytical ultracentrifugation and high precision viscometry) has shown that these polymers have properties which would potentially make them good wood consolidants. Conformation analyses with the viscosity increment (ν) universal hydrodynamic parameter and ELLIPS1 software showed that both polymers had extended conformations, facilitating in situ networking when applied to wood. SEDFIT-MSTAR analyses of sedimentation equilibrium data indicates a weight average molar mass M w of (3.9 ± 0.8) kDa and (4.2 ± 0.2) kDa for TPA6 and TPA7 respectively. Analyses with SEDFIT (sedimentation velocity) and MultiSig however revealed that TPA7 had a much greater homogeneity and a lower proportion of aggregation. These studies suggest that both these polymers—particularly TPA7—have characteristics suitable for wood consolidation, such as an optimal molar mass, conformation and a hydroxylated nature, making them interesting leads for further research.
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Ballance, Simon; Lu, Yudong; Zobel, Hanne; Rieder, Anne; Knutsen, Svein Halvor & Dinu, Vlad T.
[Show all 14 contributors for this article]
(2022).
Inter-laboratory analysis of cereal beta-glucan extracts of nutritional importance: An evaluation of different methods for determining weight-average molecular weight and molecular weight distribution.
Food Hydrocolloids.
ISSN 0268-005X.
127.
doi:
10.1016/j.foodhyd.2022.107510.
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In an interlaboratory study we compare different methods to determine the weight-average molecular weight (Mw) and molecular weight distribution of six cereal beta-glucan isolates of nutritional importance. Size-exclusion chromatography (SEC) with multi-angle light scattering (MALS), capillary viscometry, sedimentation velocity analytical ultracentrifugation and one asymmetric flow field-flow fractionation (AF4)-MALS method all yielded similar Mw values for mostly individual chains of dissolved beta-glucan molecules. SEC with post-column calcofluor detection underestimated the Mw of beta-glucan >500 × 103 g/mol. The beta-glucan molecules analysed by these methods were primarily in a random coil conformation as evidenced from individual Mark-Houwink-Kuhn-Sakurada (MHKS) scaling coefficients between 0.5 and 0.6 and Wales-Van Holde ratios between 1.4 and 1.7. In contrast, a second AF4-MALS method yielded much larger Mw values for these same samples indicating the presence and detection of beta-glucan aggregates. Storage of the six beta-glucan solutions in the dark at 4 °C for 4 years revealed them to be stable. This suggests an absence of storage-induced irreversible aggregation phenomena or chain-scission. Shear forces in SEC and the viscometer capillary and hydrostatic pressure in analytical ultracentrifugation probably led to the reversable dissociation of beta-glucan aggregates into molecularly dissolved species. Thus, all these methods yield true weight-average molecular weight values not biased by the presence of aggregates as was the case in one of the AF4 based methods employed.
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Cutajar, Michelle; Stockman, Robert A.; Braovac, Susan-Diana; Steindal, Calin Constantin; Zisi, Angeliki & Harding, Stephen Ernest
(2022).
Comparative Hydrodynamic Study on Non-Aqueous Soluble Archaeological Wood Consolidants: Butvar B-98 and PDMS-OH Siloxanes.
Molecules.
ISSN 1431-5157.
27(7).
doi:
10.3390/molecules27072133.
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Butvar B-98 and PDMS-OH both have a demonstrable ability as consolidants for archaeological wood. This makes them both potential treatment options for the Oseberg collection, which is one of the most important archaeological finds from the Viking era. Both Butvar B-98 and PDMS-OH are soluble in organic solvents, offering a useful alternative to aqueous-based consolidants. Extensive characterisation studies were carried out on both of these polymers, with the use of analytical ultracentrifugation and viscometry, for the benefit of conservators wanting to know more about the physical properties of these materials. Short column sedimentation equilibrium analysis using SEDFIT-MSTAR revealed a weight-average molar mass (weight-average molecular weight) Mw of (54.0 ± 1.5) kDa (kg · mol−1) for Butvar B-98, while four samples of PDMS-OH siloxanes (each with a different molar mass) had an Mw of (52.5 ± 3.0) kDa, (38.8 ± 1.5) kDa, (6.2 ± 0.7) kDa and (1.6 ± 0.1) kDa. Sedimentation velocity confirmed that all polymers were heterogeneous, with a wide range of molar masses. All molecular species showed considerable conformational asymmetry from measurements of intrinsic viscosity, which would facilitate networking interactions as consolidants. It is anticipated that the accumulated data on these two consolidants will enable conservators to make a more informed decision when it comes to choosing which treatment to administer to archaeological artefacts.
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Winzor, Donald J.; Dinu, Vlad; Scott, David J. & Harding, Stephen Ernest
(2021).
Quantifying the concentration dependence of sedimentation coefficients for globular macromolecules: a continuing age-old problem.
Biophysical Reviews.
ISSN 1867-2450.
13(2),
p. 273–288.
doi:
10.1007/s12551-021-00793-x.
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Bazhenova, Aleksandra; Gao, Fang; Bolgiano, Barbara & Harding, Stephen Ernest
(2021).
Glycoconjugate vaccines against Salmonella enterica serovars and Shigella species: existing and emerging methods for their analysis.
Biophysical Reviews.
ISSN 1867-2450.
13(2),
p. 221–246.
doi:
10.1007/s12551-021-00791-z.
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Lucejko, Jeannette Jacqueline; LaMotte, Anne de; Andriulo, Fabrizio; Kutzke, Hartmut; Harding, Stephen Ernest & Phillips-Jones, Mary K
[Show all 10 contributors for this article]
(2021).
Evaluation of Soda Lignin from Wheat Straw/Sarkanda Grass as a Potential Future Consolidant for Archaeological Wood.
Forests.
12(7).
doi:
10.3390/f12070911.
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This work is part of a larger study, which aims to use soda lignin from straw as the starting point for a non-aqueous consolidant for highly degraded archaeological wood from the Oseberg collection. This wood was treated with alum salts in the early 1900s, is actively degrading and exists in varying states of preservation. Non-aqueous consolidants are an option to stabilize this wood mechanically in cases where it is too deteriorated to undergo aqueous-based retreatments, for example using polyethylene glycol. The aim of this study was to compare the extent of penetration of two soda lignin preparations in low- to medium-degraded archaeological pine. The soda lignins were dissolved in ethyl acetate and had two molecular weight groups: P1000 (molecular weight Mw of~3 kDa) and the ethyl acetate fraction FB01 (Mw of ~1 kDa). Penetration after immersion was evaluated by infrared spectroscopy and analytical pyrolysis. Treated specimens were also evaluated using weight and dimensional change and scanning electron microscopy. Both lignins penetrated into sample cores, but P1000 did not penetrate as well as FB01. This may be due to differences in their molecular weights, but also differences in polarity due to the presence of different functional groups.
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Wakefield, Jennifer M.K.; Braovac, Susan-Diana; Kutzke, Hartmut; Stockman, Robert A. & Harding, Stephen Ernest
(2020).
Tert-butyldimethylsilyl chitosan synthesis and characterization by analytical ultracentrifugation, for archaeological wood conservation.
European Biophysics Journal.
ISSN 0175-7571.
49,
p. 781–791.
doi:
10.1007/s00249-020-01450-z.
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Chun, Taewoo; MacCalman, Thomas; Ottino, Sara; Dinu, Vlad; Phillips-Jones, Mary K. & Harding, Stephen Ernest
(2020).
Hydrodynamic Compatibility of Hyaluronic Acid and Tamarind Seed Polysaccharide as Ocular Mucin Supplements.
Polymers.
12(10),
p. 1–11.
doi:
10.3390/polym12102272.
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Li, Xinxin; Lu, YuDong; Adams, Gary G.; Zobel, Hanne; Ballance, Simon & Wolf, Bettina
[Show all 7 contributors for this article]
(2020).
Characterisation of the molecular properties of scleroglucan as an alternative rigid rod molecule to xanthan gum for oropharyngeal dysphagia.
Food Hydrocolloids.
ISSN 0268-005X.
101.
doi:
10.1016/j.foodhyd.2019.105446.
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Scleroglucan, a neutral β(1–3) glucan with β(1–6) glucan branches every third residue, is being considered as an alternative rod-like, shear thinning high molecular weight β-glucan based polysaccharide to xanthan gum for the management of patients with oropharyngeal dysphagia. It is therefore important to understand more fully its hydrodynamic properties in solution, in particular heterogeneity, molecular weight distribution and its behaviour in the presence of mucin glycoproteins. A commercially purified scleroglucan preparation produced by fermentation of the filamentous fungus Sclerotium rolfsii was analysed in deionised distilled water with 0.02% added azide. Sedimentation velocity in the analytical ultracentrifuge showed the scleroglucan preparation to be unimodal at concentrations >0.75 mg/ml which resolved into two components at lower concentration and with partial reversibility between the components. Sedimentation coefficient versus concentration plots showed significant hydrodynamic non-ideality. Self-association behaviour was confirmed by sedimentation equilibrium experiments with molecular weights between ~3 × 106 g/mol to ~5 × 106 g/mol after correcting for thermodynamic non-ideality. SEC-MALS-viscosity experiments showed a transition between a rod-shape at lower molar masses to a more flexible structure at higher masses consistent with previous observations. Sedimentation velocity experiments also showed no evidence for potentially problematic interactions with submaxillary mucin.
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Dinu, Vlad; Gadon, Arthur; Hurst, Katherine; Lim, Mui; Ayed, Charfeddine & Gillis, Richard B.
[Show all 9 contributors for this article]
(2019).
An enzymatically controlled mucoadhesive system for enhancing flavour during food oral processing.
npj Science of Food.
3(1),
p. 1–8.
doi:
10.1038/s41538-019-0043-y.
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While a good mucoadhesive biopolymer must adhere to a mucus membrane, it must also have a good unloading ability. Here, we demonstrate that the biopolymer pullulan is partially digested by human salivary α-amylase, thus acting as a controlled release system, in which the enzyme triggers an increased release of flavour. Our oral processing simulations have confirmed an increase in the bioavailability of aroma and salt compounds as a function of oral pullulan degradation, although the release kinetics suggest a rather slow process. One of the greatest challenges in flavour science is to retain and rapidly unload the bioactive aroma and taste compounds in the oral cavity before they are ingested. By developing a cationic pullulan analogue we have, in theory, addressed the “loss through ingestion” issue by facilitating the adhesion of the modified polymer to the oral mucus, to retain more of the flavour in the oral cavity. Dimethylaminoethyl pullulan (DMAE-pullulan) was synthesised for the first time, and shown to bind submaxillary mucin, while still retaining its susceptibility to α-amylase hydrolysis. Although DMAE-pullulan is not currently food grade, we suggest that the synthesis of a sustainable food grade alternative would be a next generation mucoadhesive targeted for the oral cavity.
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Dinu, Vlad; Yabukov, Gleb E.; Lim, Mui; Hurst, Katherine; Adams, Gary G. & Harding, Stephen Ernest
[Show all 7 contributors for this article]
(2019).
Mucin immobilization in calcium alginate: A possible mucus mimetic tool for evaluating mucoadhesion and retention of flavour.
International Journal of Biological Macromolecules.
ISSN 0141-8130.
138,
p. 831–836.
doi:
10.1016/j.ijbiomac.2019.07.148.
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To reduce animal testing, there is a need to develop novel in-vitro models for evaluating the retention of bioactive compounds in food and pharmaceutical products. Here, a mucus-mimetic platform was developed through a one-step approach based on encapsulating mucin within alginate gel beads. We found that mucins form micron sized aggregates distributed across the surface of the calcium-alginate bead, as shown by environmental scanning electron microscopy (ESEM). Retention of bioactive compounds on the mucin-functionalised surface was tested using a commercial orange drink formulation. To aid flavour retention, different mucoadhesive polymers with varying charge, including anionic, neutral and strongly cationic, were tested for their ability to interact with mucin and aid retaining flavour compounds within the mucin-alginate bead. The alginate-mucin mucus mimic was validated using an ex-vivo bovine tongue, with the flavour retention results showing qualitative agreement. The developed method proved to be a convenient, efficient tool for providing information on the effectiveness of mucoadhesive polymers without variability, safety and sustainability issues associated with an ex-vivo or in-vivo system. We propose that by encapsulating other relevant oral proteins, alongside mucins, current gaps between in-vitro and the ex-vivo systems may be narrowed.
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Phillips-Jones, Mary K & Harding, Stephen Ernest
(2019).
Tapping into synchrotron and benchtop circular dichroism spectroscopy for expanding studies of complex polysaccharides and their interactions in anoxic archaeological wood.
Heritage.
2(1),
p. 121–134.
doi:
10.3390/heritage2010009.
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Circular dichroism (CD) (and synchrotron circular dichroism (SCD)) spectroscopy is a rapid, highly sensitive technique used to investigate structural conformational changes in biomolecules in response to interactions with ligands in solution and in film. It is a chiroptical method and at least one of the interacting molecules must possess optical activity (or chirality). In this review, we compare the capabilities of CD and SCD in the characterisation of celluloses and lignin polymers in archaeological wood. Cellulose produces a range of spectral characteristics dependent on environment and form; many of the reported transitions occur in the vacuum-ultraviolet region (< 180 nm) most conveniently delivered using a synchrotron source. The use of induced CD in which achiral dyes are bound to celluloses to give shifted spectra in the visible region is also discussed, together with its employment to identify the handedness of the chiral twists in nanocrystalline cellulose. Lignin is one target for the design of future consolidants that interact with archaeological wood to preserve it. It is reportedly achiral, but here we review several studies in which CD spectroscopy has successfully revealed lignin interactions with chiral enzymes, highlighting the potential usefulness of the technique in future research to identify new generation consolidants.
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Dinu, Vlad; Gillis, Richard B; MacCalman, Thomas; Lim, Mui; Adams, Gary G. & Harding, Stephen Ernest
[Show all 7 contributors for this article]
(2019).
Submaxillary Mucin: its Effect on Aroma Release from Acidic Drinks and New Insight into the Effect of Aroma Compounds on its Macromolecular Integrity.
Food Biophysics.
ISSN 1557-1858.
14(3),
p. 278–286.
doi:
10.1007/s11483-019-09574-2.
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Submaxillary mucin is a major component that defines the makeup and functionality of saliva. Understanding its structure and function during food intake is key to designing appropriate strategies for enhancing the delivery of flavour. In the present study, the hydrodynamic integrity of bovine submaxillary mucin was characterised under physiological and acidic conditions and it was shown to have a broad molecular weight distribution with species ranging from 100 kDa to over 2000 kDa, and a random coil type of conformation. A decrease in the pH of mucin appeared to result in aggregation and a broader molecular weight distribution, which was shown to correlate with a release of flavour compounds. Our study also provides indications that p-cresol may have an effect on the macromolecular integrity of mucin.
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Gadon, Arthur; Linforth, Robert; Harding, Stephen Ernest & Cook, David
(2019).
Characterisation of high molecular weight hop proanthocyanidins using Analytical Ultracentrifugation.
Scientific Reports.
9(1),
p. 1–8.
doi:
10.1038/s41598-019-49171-4.
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We report the novel application of Analytical Ultracentrifugation (AUCF) to characterise the polymeric proanthocyanidin fraction of hops. Extraction of hop samples with 70% acetone (aq) followed by a C-18 Solid Phase Extraction yielded polyphenolic fractions for AUCF analysis. Sedimentation velocity experiments demonstrated the presence of discrete molecular weight bands of proanthocyanidins, as opposed to a continuous distribution of molecular weights. There were 4 such bands for Saaz hop (0.15, 1.1, 2.7 and 4.4S) and 3 bands for Magnum (0.15, 1.6 and 3.0S). The method resulted in a reproducible size (sedimentation coefficient) distribution for replicate runs of the same extract and for extracts prepared from different samples of the same hop variety. Sedimentation equilibrium experiments were then used to fit molecular weight distributions using the new SEDFIT-MSTAR method for the same samples. Thus we report for the first time polymeric proanthocyanidins in hops with molecular weights of up to 100 kDa in Saaz hop (or up to 56 kDa in Magnum). This represents the first application of AUCF to characterise complex fractions of polyphenolics extracted from botanical sources and the methodology developed should find wider application in the study of this diverse and bioactive class of compounds.
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Channell, Guy; Dinu, Vlad; Adams, Gary G. & Harding, Stephen Ernest
(2018).
A simple cell-alignment protocol for sedimentation velocity analytical ultracentrifugation to complement mechanical and optical alignment procedures.
European Biophysics Journal.
ISSN 0175-7571.
47(7),
p. 809–813.
doi:
10.1007/s00249-018-1328-9.
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In establishing the sources of data variability within sedimentation velocity analysis in the analytical ultracentrifuge and their relative importance, recent studies have demonstrated that alignment of the sample cells to the centre of rotation is the most significant contributing factor to overall variability, particularly for the characterisation of low levels of protein aggregation. Accurate mechanical and optical alignment tools have been recently designed. In this study, we (1) confirm the effect of misalignment observed by others on the estimated amounts of bovine serum albumin (BSA) monomer and dimer, and the sedimentation coefficient value for the BSA dimer; and (2) demonstrate the high performance of a mechanical alignment tool and the usefulness of a simple and complementary enhanced manual alignment protocol which should be useful for situations where these tools are not available.
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Harding, Stephen Ernest
(2018).
The Svedberg Lecture 2017. From nano to micro: the huge dynamic range of the analytical ultracentrifuge for characterising the sizes, shapes and interactions of molecules and assemblies in Biochemistry and Polymer Science.
European Biophysics Journal.
ISSN 0175-7571.
47(7),
p. 697–707.
doi:
10.1007/s00249-018-1321-3.
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The analytical ultracentrifuge (AUC) invented by T. Svedberg has now become an extremely versatile and diverse tool in Biochemistry and Polymer Science for the characterisation of the sizes, shapes and interactions of particles ranging in size from a few nanometres to tens of microns, or in molecular weight, M (molar mass) terms from a few hundred daltons to hundreds of megadaltons. We illustrate this diversity by reviewing recent work on (1) small lignin-like isoeugenols of M ~ 0.4–0.9 kDa for archaeological wood conservation, (2) protein-like association of a functional amino-cellulose M = 3.25 kDa, (3) a small glycopeptide antibiotic (M ~ 1.5 kDa) and its association with a protein involved in antibiotic resistance (M ~ 47 kDa), (4) tetanus toxoid protein TTP (M ~ 150 kDa) and (5) the incorporation of TTP into two huge glycoconjugates considered in glycovaccine development with molecular weight species in a broad distribution appearing to reach 100 MDa. In illustrating the diversity, we will highlight developments in hydrodynamic analysis which have made the AUC such an exciting and important instrument, and point to a potential future development for extending its capability to highly concentrated systems.
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Channel, Guy A.; Adams, Gary G.; Lu, YuDong; Gillis, Richard B.; Dinu, Vlad & Grundy, Myriam
[Show all 12 contributors for this article]
(2018).
Use of the Extended Fujita method for representing the
molecular weight and molecular weight distributions of native and processed oat beta-glucans.
Scientific Reports.
8:11809,
p. 1–8.
doi:
10.1038/s41598-018-29997-0.
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Beta 1–3, 1–4 glucans (“beta-glucans”) are one of the key components of the cell wall of cereals, complementing the main structural component cellulose. Beta-glucans are also an important source of soluble fibre in foods containing oats with claims of other beneficial nutritional properties such as plasma cholesterol lowering in humans. Key to the function of beta-glucans is their molecular weight and because of their high polydispersity - molecular weight distribution. Analytical ultracentrifugation provides a matrix-free approach (not requiring separation columns or media) to polymer molecular weight distribution determination. The sedimentation coefficient distribution is converted to a molecular weight distribution via a power law relation using an established procedure known as the Extended Fujita approach. We establish and apply the power law relation and Extended Fujita method for the first time to a series of native and processed oat beta-glucans. The application of this approach to beta-glucans from other sources is considered.
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Wakefield, Jennifer M.K.; Gillis, Richard B.; Adams, Gary G.; McQueen, Caitlin & Harding, Stephen Ernest
(2018).
Controlled depolymerisation assessed by Analytical Ultracentrifugation of low molecular
weight chitosan for use in archaeological conservation.
European Biophysics Journal.
ISSN 0175-7571.
47(7),
p. 769–775.
doi:
10.1007/s00249-018-1290-6.
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The heterogeneity and molecular weight of a chitosan of low molecular weight (molar mass) and low degree of acetylation (0.1) for potential use as a consolidant for decayed archaeological wood were examined by sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge before and after depolymerisation. Sedimentation velocity before depolymerisation revealed a uniform distribution of sedimentation coefficient with little concentration dependence. SEDFIT-MSTAR analysis revealed a weight average molecular weight Mw of (14.2 ± 1.2) kDa, and polydispersity index of ~ 1.2. Further analysis using MULTISIG revealed a distribution of material between 2 and 20 kDa and consistent with the weight average Mw. Controlled depolymerisation using hydrogen peroxide and ultra-violet radiation in an acetic acid medium reduced this to (4.9 ± 0.7) kDa, with a similar polydispersity. The depolymerised material appears to be within the range that has been predicted to fully penetrate into archaeological wood. The consequences for this finding and the use of the analytical ultracentrifuge in wood conservation strategies are considered.
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Harding, Stephen Ernest; Channell, Guy & Phillips-Jones, Mary K
(2018).
The discovery of hydrogen bonds in DNA and a re-evaluation of the 1948 Creeth two-chain model for its structure.
Biochemical Society Transactions.
ISSN 0300-5127.
46(5),
p. 1171–1182.
doi:
10.1042/BST20180158.
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We recall the experimental approaches involved in the discovery of hydrogen bonds in deoxyribonucleic acid (DNA) made 70 years ago by a team of scientists at University College Nottingham led by J.M. Gulland, and in relation to previous studies. This discovery proved an important step in the elucidation of the correct structure for DNA made by J.D. Watson and F.H.C. Crick, as acknowledged in ‘The Double Helix’. At that time of the discovery, however, it was impossible to delineate between inter- and intra-chain hydrogen bonds. We also consider in the light of more recent hydrodynamic theory a tentative model for DNA proposed by Gulland's and D.O. Jordan's PhD student J.M. Creeth in his PhD thesis of 1948, with the correct prediction of two chains with a sugar-phosphate backbone on the exterior and hydrogen-bonded bases between the nucleotide bases of opposite chains in the interior. Our analysis shows that his incorporation of alternating breaks in the two-chain structure was not necessary to explain the viscosity data on scission of hydrogen bonds after titrating to high or low pH. Although Creeth's model is a depiction of DNA structure alone, he could not know whether the hydrogen bonding was intermolecular, although this was subsequently proved correct by others. The mechanisms by which replicative processes occurred were of course unknown at that time, and so, he could not have realised how closely his tentative model resembled steps in some viral replicative mechanisms involving the molecule of life that he was working on.
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McHale, Emily; Steindal, Calin Constantin; Kutzke, Hartmut; Benneche, Tore & Harding, Stephen Ernest
(2017).
In situ polymerisation of isoeugenol as a green consolidation method for waterlogged archaeological wood.
Scientific Reports.
7.
doi:
10.1038/srep46481.
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Waterlogged archaeological wood is often in need of consolidation prior to drying to prevent shrinkage and cracking of the object. There is a need for new greener materials (than for example polyethylene glycol) and methods for consolidation to be developed. The use of wood-based components could provide good interaction between the consolidant and the remaining wood structure and would also support a shift away from fossil fuel-based materials to those with more sustainable sources. Based on this, lignin-like structures have been investigated for their ability to consolidate waterlogged archaeological wood. The in situ formation of a lignin-like material has been carried out using isoeugenol polymerised by horse radish peroxidase in aqueous solution. The formation of the oligomeric/polymeric materials within the wood following this reaction has been determined by Attenuated Total Reflectance Fourier Transform Infra Red (ATR-FTIR) spectroscopy. The oligomers remaining in solution have been characterised by ATR-FTIR and nuclear magnetic resonance (NMR) spectroscopy as well as analytical ultracentrifugation, showing that they have a weight average Mw of 0.4–0.9 kDa and a lignin-like structure rich in the β-5′ moiety. Therefore, this approach is proposed as a basis to further develop a green consolidation method for waterlogged archaeological wood.
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Published
Nov. 27, 2017 1:15 PM
- Last modified
Mar. 20, 2020 3:06 PM
