| 1. |
- Abramsson, Alexandra, 1973, et al.
(author)
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Proteomics Profiling of Single Organs from Individual Adult Zebrafish.
- 2010
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In: Zebrafish. - : Mary Ann Liebert Inc. - 1557-8542 .- 1545-8547. ; 7:2, s. 161-168
-
Journal article (peer-reviewed)abstract
- Abstract The model organism zebrafish (Danio rerio) is extensively utilized in studies of developmental biology but is also being investigated in the context of a growing list of human age-related diseases. To facilitate such studies, we here present protein expression patterns of adult zebrafish organs, including blood, brain, fin, heart, intestine, liver, and skeletal muscle. Protein extracts were prepared from the different organs of two zebrafish and analyzed using liquid chromatography coupled to high-resolution tandem mass spectrometry. Zebrafish tissue was digested directly after minimal fractionation and cleaned up (the shotgun approach). Proteins were identified using Mascot software. In total, 1394 proteins were identified of which 644 were nonredundant. Of these, 373 demonstrated an organ-specific expression pattern and 57 had not been shown on protein level before. These data emphasize the need for increased research at the protein level to facilitate the selection of candidate proteins for targeted quantification and to refine systematic genetic network analysis in vertebrate development, biology, and disease.
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| 2. |
- Aggarwal, Ruchi, et al.
(author)
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Cellulose-Derived Carbon Dots for Inner Filter Effect-Based Selective Sensing of Ofloxacin Antibiotics
- 2023
-
In: ACS Applied Nano Materials. - 2574-0970. ; 6:8, s. 6518-6527
-
Journal article (peer-reviewed)abstract
- A two-step viable synthetic approach for quick and energy-efficient acid-based charring is described here to fabricate self-passivated fluorescent water-soluble CD (wsCD) from sustainable microcrystalline cellulose (MCC) materials. The aqueous solution of wsCD exhibits blue emission under UV-light illumination and shows a fluorescence quantum yield of ∼6%. The wsCD are used here for the selective sensing of ofloxacin (OFLX) from among the four tested antibiotics of the fluoroquinolone class, namely, ciprofloxacin (CPLX), ofloxacin (OFLX), levofloxacin (LVLX), and moxifloxacin (MXLX) based on the simpler fluorescence quenching experiment with a detection limit of ∼0.025 ppm. The plausible mechanism for the selective sensing of OFLX has been proposed based on a detailed analysis of absorbance and time-resolved photoluminescence spectroscopy which indicates the involvement of the inner-filter effect (IFE). Antimicrobial studies of wsCD were conducted on two bacterial strains (Escherichia coli and Staphylococcus aureus) and two fungal strains (Aspergillus niger and Penicillium chrysogenum), where wsCD did not show any toxic effects up to the concentration of 1 mg/mL, hence supporting their biocompatible behavior. Further, an antibiosis study involving the combination of the antibiotic and antifungal agents with wsCD against the growth of the same bacterial and fungal strains was conducted, where wsCD showed mild antifungal activity.
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| 3. |
- Aggarwal, Ruchi, et al.
(author)
-
Cellulose Nanocrystals Derived from Microcrystalline Cellulose for Selective Removal of Janus Green Azo Dye
- 2023
-
In: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 62:1, s. 649-659
-
Journal article (peer-reviewed)abstract
- Cellulose nanocrystals (CNCs) as a bio-based adsorbent material have been synthesized at mild temperature reaction conditions using acid hydrolysis of microcrystalline cellulose (MCC) by sulfuric acid. CNCs by a simple acid treatment become enriched with negatively charged surface functionalities and shows good adsorption capacity. The CNCs have been characterized by X-ray photoelectron spectroscopy, Fourier transform Infrared, X-ray diffraction spectroscopy, and thermogravimetric analysis for their chemical composition, functionality, crystallinity, and stability, respectively. Sulfated CNCs have been used to selectively remove the toxic Janus Green (JG) dye tested out of many other dyes via adsorption and showed a Langmuir adsorption capacity of 77 mg g. -1 The effects of pH, temperature, concentration, and loading capacity have also been explored. The adsorption kinetics follows the pseudo-second-order pathway and thermodynamic analysis of the system indicates that the process is exothermic and spontaneous. Moreover, for the practical applicability of the proposed method, the adsorption of JG was also analyzed in four spiked industrial samples collected from nearby textile industries, where they removed more than 80% of the dye from the complex industrial water system.
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| 4. |
- Aggarwal, Ruchi, et al.
(author)
-
From Bulk Molybdenum Disulfide (MoS 2 ) to Suspensions of Exfoliated MoS 2 in an Aqueous Medium and Their Applications
- 2024
-
In: Langmuir. - 1520-5827 .- 0743-7463. ; 40:19, s. 9855-9872
-
Research review (peer-reviewed)abstract
- Two-dimensional (2D) layered materials like graphene, transition-metal dichalcogenides (TMDs), boron nitrides, etc., exhibit unique and fascinating properties, such as high surface-to-volume ratio, inherent mechanical flexibility and robustness, tunable bandgap, and high carrier mobility, which makes them an apt candidate for flexible electronics with low consumption of power. Because of these properties, they are in tremendous demand for advancement in energy, environmental, and biomedical sectors developed through various technologies. The production and scalability of these materials must be sustainable and ecofriendly to utilize these unique properties in the real world. Here, in this current review, we review molybdenum disulfide (MoS2 nanosheets) in detail, focusing on exfoliated MoS2 in water and the applicability of aqueous MoS2 suspensions in various fields. The exfoliation of MoS2 results in the formation of single or few-layered MoS2. Therefore, this Review focuses on the few layers of exfoliated MoS2 that have the additional properties of 2D layered materials and higher excellent compatibility for integration than existing conventional Si tools. Hence, a few layers of exfoliated MoS2 are widely explored in biosensing, gas sensing, catalysis, photodetectors, energy storage devices, a light-emitting diode (LED), adsorption, etc. This review covers the numerous methodologies to exfoliate MoS2, focusing on the various published methodologies to obtain nanosheets of MoS2 from water solutions and their use.
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| 5. |
- Aggarwal, Ruchi, et al.
(author)
-
Nitrogen-Doped Carbon Nanoflakes by Acidic Charring of Microcrystalline Cellulose and Urea for the Rapid Removal of Imidacloprid from Water
- 2024
-
In: ACS Applied Nano Materials. - 2574-0970. ; 7:1, s. 1-10
-
Research review (peer-reviewed)abstract
- Herein, cellulose as a natural biomass along with urea was acid-charred to synthesize nitrogen-doped carbon nanoflakes (N-CNF). The as-prepared N-CNF was used to rapidly remove the effluent of agricultural waste containing an Imidacloprid (IMD) insecticide. The adsorption data fit well to nonlinearly in the Sips adsorption model, which is a mixed Langmuir-Freundlich model with an adsorption capacity of ∼104.9 mg g-1. The adsorption follows pseudo-second-order kinetics linearly and nonlinearly, and thermodynamic parameters reveal that the adsorption process was spontaneous and endothermic. The effect of pH and the interference of ions was also checked. Further, spiking of IMD in different soil, lake, and tap wastewater samples was also done to enhance the practical applicability of removing IMD by N-CNF. The antibacterial properties of N-CNF were checked on both Gram-negative and Gram-positive bacterial strains as Escherichia coli and Bacillus subtilus, respectively, where they showed nontoxic behavior up to the concentration of 2 mg mL-1
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| 6. |
- Aggarwal, Ruchi, et al.
(author)
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Sunlight promoted removal of toxic hexavalent chromium by cellulose derived photoactive carbon dots
- 2022
-
In: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 287
-
Journal article (peer-reviewed)abstract
- A scalable synthetic procedure for fabricating photoactive carbon dots (CD) from microcrystalline cellulose (MCC) is presented. The MCC was transformed into a photoactive nanosized CD by a one-step acid-assisted thermal-carbonization (~90 °C for 30 min). The efficiency of the obtained CD was determined by photo-removal of toxic hexavalent chromium (Cr(VI)) ions from wastewater. CD obtained from cellulose completely removed 20 ppm of Cr(VI) wastewater within ∼120 min under sunlight illumination. No Cr(VI) removal was observed in dark conditions and with control cellulose material as reference samples. The Cr(VI) removal follows pseudo-first-order kinetics along with a half-life of ∼26 min. Furthermore, the Cr(VI) removal from wastewater was supported via cyclic voltammetry analysis. Using a low-cost, naturally available cellulose material and sulfuric acid, the world's most-used chemical, creates techno-economic prerequisites for a scalable process of photoactive carbon dots.
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| 7. |
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| 8. |
- Arino Marine, Ruth, 1980, et al.
(author)
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Thermal and viscoelastic properties of cellulosic gels with different ionic liquids and coagulation agents
- 2013
-
In: BioResources. - 1930-2126 .- 1930-2126. ; 8:2, s. 2209-2221
-
Journal article (peer-reviewed)abstract
- Thermal and viscoelastic properties of three-component gels consisting of microcrystalline cellulose, ionic liquid, and coagulation agent were studied. The amount and type of components was varied to obtain different gel properties. The absorption of coagulation agent (13 to 35 %wt of water or ethanol) was found to depend on the types of ionic liquid and cellulose. Surface hydrophobization of cellulose prior to preparation of the gel remarkably resulted in the gels containing the most coagulation agent (35%wt). Rheological studies indicated a linear viscoelastic behavior in storage modulus but not in loss modulus, which is a behavior that, according to our knowledge, has not been seen before for gels. Increasing the cellulose concentration from 1:20 to 1:10 increased the stiffness of the gels. The highest critical stress value (1050 Pa) was obtained for a gel containing 1-butyl-3-methylimidazolium chloride and water. Finally, it was confirmed by dynamic-mechanical experiments that the gels had a cross-linked structure.
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| 9. |
- Brinkmalm, Gunnar, et al.
(author)
-
A Parallel Reaction Monitoring Mass Spectrometric Method for Analysis of Potential CSF Biomarkers for Alzheimer's Disease.
- 2018
-
In: Proteomics. Clinical applications. - : Wiley. - 1862-8354 .- 1862-8346. ; 12:1
-
Journal article (peer-reviewed)abstract
- The aim of this study was to develop and evaluate a parallel reaction monitoring mass spectrometry (PRM-MS) assay consisting of a panel of potential protein biomarkers in cerebrospinal fluid (CSF).Thirteen proteins were selected based on their association with neurodegenerative diseases and involvement in synaptic function, secretory vesicle function, or innate immune system. CSF samples were digested and two to three peptides per protein were quantified using stable isotope-labeled peptide standards.Coefficients of variation were generally below 15%. Clinical evaluation was performed on a cohort of 10 patients with Alzheimer's disease (AD) and 15 healthy subjects. Investigated proteins of the granin family exhibited the largest difference between the patient groups. Secretogranin-2 (p<0.005) and neurosecretory protein VGF (p<0.001) concentrations were lowered in AD. For chromogranin A, two of three peptides had significantly lowered AD concentrations (p<0.01). The concentrations of the synaptic proteins neurexin-1 and neuronal pentraxin-1, as well as neurofascin were also significantly lowered in AD (p<0.05). The other investigated proteins, β2-microglobulin, cystatin C, amyloid precursor protein, lysozyme C, neurexin-2, neurexin-3, and neurocan core protein, were not significantly altered.PRM-MS of protein panels is a valuable tool to evaluate biomarker candidates for neurodegenerative disorders.
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| 10. |
- Brinkmalm, Gunnar, et al.
(author)
-
An online nano-LC-ESI-FTICR-MS method for comprehensive characterization of endogenous fragments from amyloid β and amyloid precursor protein in human and cat cerebrospinal fluid.
- 2012
-
In: Journal of mass spectrometry : JMS. - : Wiley. - 1096-9888 .- 1076-5174. ; 47:5, s. 591-603
-
Journal article (peer-reviewed)abstract
- Amyloid precursor protein (APP) is the precursor protein to amyloid β (Aβ), the main constituent of senile plaques in Alzheimer's disease (AD). Endogenous Aβ peptides reflect the APP processing, and greater knowledge of different APP degradation pathways is important to understand the mechanism underlying AD pathology. When one analyzes longer Aβ peptides by low-energy collision-induced dissociation tandem mass spectrometry (MS/MS), mainly long b-fragments are observed, limiting the possibility to determine variations such as amino acid variants or post-translational modifications (PTMs) within the N-terminal half of the peptide. However, by using electron capture dissociation (ECD), we obtained a more comprehensive sequence coverage for several APP/Aβ peptide species, thus enabling a deeper characterization of possible variants and PTMs. Abnormal APP/Aβ processing has also been described in the lysosomal storage disease Niemann-Pick type C and the major large animal used for studying this disease is cat. By ECD MS/MS, a substitution of Asp7 → Glu in cat Aβ was identified. Further, sialylated core 1 like O-glycans at Tyr10, recently discovered in human Aβ (a previously unknown glycosylation type), were identified also in cat cerebrospinal fluid (CSF). It is therefore likely that this unusual type of glycosylation is common for (at least) species belonging to the magnorder Boreoeutheria. We here describe a detailed characterization of endogenous APP/Aβ peptide species in CSF by using an online top-down MS-based method.
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| 11. |
- Brinkmalm, Gunnar, et al.
(author)
-
Soluble amyloid precursor protein α and β in CSF in Alzheimer's disease.
- 2013
-
In: Brain research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1513, s. 117-26
-
Journal article (peer-reviewed)abstract
- Cerebral accumulation of amyloid β (Aβ) is a pathological hallmark of Alzheimer's disease (AD). Proteolytic processing of amyloid precursor protein (APP) by α- or β-secretase results in two soluble metabolites, sAPPα and sAPPβ, respectively. However, previous data have shown that both α- and β-secretase have multiple cleavage sites. The aim of this study was to characterize the C-termini of sAPPα and sAPPβ in cerebrospinal fluid (CSF) by mass spectrometry (MS) and to evaluate whether different combinations of these fragments better separate between AD patients and controls by comparing two different sAPP immunoassays. Methods: Using immunoprecipitation and high resolution MS, the APP species present in CSF were investigated. CSF levels of sAPPα and sAPPβ from patients with AD (n=43) and from non-demented controls (n=44) were measured using AlphaLISA and MSD immunoassays that employ different antibodies for C-terminal recognition of sAPPα. Results: Four different C-terminal forms of sAPP were identified, sAPPβ-M671, sAPPβ-Y681, sAPPα-Q686, and sAPPα-K687 (APP770 numbering). Neither immunoassay for the sAPP species could separate the two patient groups. The correlation (R(2)) between the two immunoassays was 0.41 for sAPPα and 0.45 for sAPPβ. Conclusion: Using high resolution MS, we show here for the first time that sAPPα in CSF ends at Q686 and K687. The findings also support the conclusion from several previous studies that sAPPα and sAPPβ levels are unaltered in AD.
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| 12. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
A Mass Spectrometer´s Building Blocks
- 2009
-
In: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 15-87
-
Book chapter (other academic/artistic)abstract
- This chapter contains sections titled: * Ion Sources * Mass Analyzers * Detectors * References
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| 13. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Definitions and Explanations
- 2009
-
In: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 3-13
-
Book chapter (other academic/artistic)abstract
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| 14. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Explorative and targeted neuroproteomics in Alzheimer's disease.
- 2015
-
In: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1854:7, s. 769-778
-
Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) is a progressive brain amyloidosis that injures brain regions involved in memory consolidation and other higher brain functions. Neuropathologically, the disease is characterized by accumulation of a 42 amino acid peptide called amyloid β (Aβ42) in extracellular senile plaques, intraneuronal inclusions of hyperphosphorylated tau protein in neurofibrillary tangles, and neuronal and axonal degeneration and loss. Biomarker assays capturing these pathologies have been developed for use on cerebrospinal fluid samples but there are additional molecular pathways that most likely contribute to the neurodegeneration and full clinical expression of AD. One way of learning more about AD pathogenesis is to identify novel biomarkers for these pathways and examine them in longitudinal studies of patients in different stages of the disease. Here, we discuss targeted proteomic approaches to study AD and AD-related pathologies in closer detail and explorative approaches to discover novel pathways that may contribute to the disease. This article is part of a Special Issue entitled: Neuroproteomics: Applications in neuroscience and neurology.
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| 15. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Fluid-based proteomics targeted on pathophysiological processes and pathologies in neurodegenerative diseases.
- 2019
-
In: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 151:4, s. 417-434
-
Journal article (peer-reviewed)abstract
- Neurodegenerative dementias constitute a broad group of diseases in which abnormally folded proteins accumulate in specific brain regions and result in tissue reactions that eventually cause neuronal dysfunction and degeneration. Depending on where in the brain this happens, symptoms appear which may be used to classify the disorders on clinical grounds. However, brain changes in neurodegenerative dementias start to accumulate many years prior to symptom onset and there is a poor correlation between the clinical picture and what pathology that is the most likely to cause it. Thus, novel drug candidates having disease-modifying effects that is targeting the underlying pathology and changes the course of the disease needs to be defined using objective biomarker-based measures since the clinical symptoms are often non-specific and overlap between different disorders. Furthermore, the treatment should ideally be initiated as soon as symptoms are evident or when biomarkers confirm an underlying pathology (pre-clinical phase of the disease) to reduce irreversible damage to, for example, neurons, synapses and axons. Clinical trials in the pre-clinical phase bring a greater importance to biomarkers since by definition the clinical effects are difficult or slow to discern in a population that is not yet clinically affected. Here, we discuss neuropathological changes that may underlie neurodegenerative dementias, including how they can be detected and quantified using currently available biofluid-based biomarkers and how more of them could be identified using targeted proteomics approaches.
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| 16. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Proteomics/peptidomics tools to find CSF biomarkers for neurodegenerative diseases.
- 2009
-
In: Frontiers in bioscience : a journal and virtual library. - : IMR Press. - 1093-4715. ; 14, s. 1793-806
-
Research review (peer-reviewed)abstract
- Neurodegenerative diseases are characterized by premature neuronal loss in specific brain regions. During the past decades our knowledge on molecular mechanisms underlying neurodegeneration has increased immensely and resulted in promising drug candidates that might slow down or even stop the neuronal loss. These advances have put a strong focus on the development of diagnostic tools for early or pre-clinical detection of the disorders. In this review we discuss our experience in the field of neuroproteomics/peptidomics, with special focus on biomarker discovery studies that have been performed on CSF samples from well-defined patient and control populations.
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| 17. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Separation Methods
- 2009
-
In: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 105-115
-
Book chapter (other academic/artistic)abstract
- This chapter contains sections titled: * Chromatography * Electric-Field Driven Separations * References
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| 18. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
SILAC zebrafish for quantitative analysis of protein turnover and tissue regeneration.
- 2011
-
In: Journal of proteomics. - : Elsevier BV. - 1876-7737 .- 1874-3919. ; 75:2, s. 425-34
-
Journal article (peer-reviewed)abstract
- Defective tissue regeneration is thought to contribute to several human diseases, including neurodegenerative disorders, heart failure and various lung diseases. Boosting the regenerative capacity has been suggested a possible therapeutic approach. Methods to metabolically label newly synthesized proteins in vivo with stable isotopic forms of amino acids holds promise for the study of protein turnover and tissue regeneration that are fundamental to the sustained life of all organisms. Here, we used the "stable isotope labeling with amino acids in cell culture" (SILAC) approach to explore normal protein turnover and tissue regeneration in adult zebrafish. The ratio of labeled and unlabeled proteins/peptides in specific organs of zebrafish fed a SILAC diet containing (13)C(6)-labeled lysine was determined by liquid chromatography and tandem mass spectrometry. Labeling was highest in tissues with high regenerative capacity, including intestine, liver, and fin, whereas brain and heart displayed the lowest labeling. Proteins with high degree of labeling were mainly involved in catalytic or transport activity pathways. The technique also verified increased protein synthesis during regeneration of the caudal fin following amputation. This newly developed SILAC zebrafish model constitutes a novel tool to analyze tissue regeneration in an animal model amenable to genetic and pharmacologic manipulation.
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| 19. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
SNAP-25 is a promising novel cerebrospinal fluid biomarker for synapse degeneration in Alzheimer's disease
- 2014
-
In: Molecular Neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 9
-
Journal article (peer-reviewed)abstract
- Background: Synaptic degeneration is an early pathogenic event in Alzheimer's disease, associated with cognitive impairment and disease progression. Cerebrospinal fluid biomarkers reflecting synaptic integrity would be highly valuable tools to monitor synaptic degeneration directly in patients. We previously showed that synaptic proteins such as synaptotagmin and synaptosomal-associated protein 25 (SNAP-25) could be detected in pooled samples of cerebrospinal fluid, however these assays were not sensitive enough for individual samples. Results: We report a new strategy to study synaptic pathology by using affinity purification and mass spectrometry to measure the levels of the presynaptic protein SNAP-25 in cerebrospinal fluid. By applying this novel affinity mass spectrometry strategy on three separate cohorts of patients, the value of SNAP-25 as a cerebrospinal fluid biomarker for synaptic integrity in Alzheimer's disease was assessed for the first time. We found significantly higher levels of cerebrospinal fluid SNAP-25 fragments in Alzheimer's disease, even in the very early stages, in three separate cohorts. Cerebrospinal fluid SNAP-25 differentiated Alzheimer's disease from controls with area under the curve of 0.901 (P < 0.0001). Conclusions: We developed a sensitive method to analyze SNAP-25 levels in individual CSF samples that to our knowledge was not possible previously. Our results support the notion that synaptic biomarkers may be important tools for early diagnosis, assessment of disease progression, and to monitor drug effects in treatment trials.
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| 20. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Tandem Mass Spectrometry
- 2009
-
In: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 89-103
-
Book chapter (other academic/artistic)abstract
- This chapter contains sections titled: * Tandem MS Analyzer Combinations * Ion Activation Methods * References
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| 21. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
-
Targeting synaptic pathology with a novel affinity mass spectrometry approach.
- 2014
-
In: Molecular & cellular proteomics : MCP. - 1535-9484. ; 13:10, s. 2584-92
-
Journal article (peer-reviewed)abstract
- We report a novel strategy for studying synaptic pathology by concurrently measuring levels of four SNARE complex proteins from individual brain tissue samples. This method combines affinity purification and mass spectrometry and can be applied directly for studies of SNARE complex proteins in multiple species or modified to target other key elements in neuronal function. We use the technique to demonstrate altered levels of presynaptic proteins in Alzheimer disease patients and prion-infected mice.
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| 22. |
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| 23. |
- Bylin, Susanne, 1982, et al.
(author)
-
Solvation behavior of cellulose and xylan in the MIM/EMIMAc ionic liquid solvent system – parameters for small scale solvation
- 2014
-
In: BioResources. - : BioResources. - 1930-2126 .- 1930-2126. ; 9:1, s. 1038-1054
-
Journal article (peer-reviewed)abstract
- Ionic liquid treatment has been reported by several researchers as a possible step in the process of fractionating lignocellulosic biomass within the biorefinery concept. However, understanding how solvation can be achieved and how the feedstock biopolymers are affected is needed prior to a viable implementation. An effective two component solvent system for the wood components cellulose and xylan has been developed. Furthermore, the solvation of these components in the system consisting of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate (EMIMAc) in a novel combination with the co-solvent 1-methylimidazole (MIM) is investigated. Focused beam reflectance measurement (FBRM) particle characterization in combination with microscopic analysis and molecular weight determinations (xylan) shows that cellulose and xylan can be most efficiently solvated using only 3 to 4% IL (n/n anhydro-glucose units and n/n anhydro-xylose units) and 9% IL, respectively, while still avoiding any significant polymer degradation. A model for a two-step process of cellulose solvation in the present system is proposed.
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| 24. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
Arabinoxylan and Nanocellulose from a Kilogram-scale Extraction of Barley Husk
- 2019
-
In: BioResources. - : BioResources. - 1930-2126 .- 1930-2126. ; 13:3, s. 6201-6220
-
Journal article (peer-reviewed)abstract
- Processes of extracting hemicellulose from annual plants usually neglect the cellulose fraction. This study explored the possibility of obtaining both a hemicellulose and a cellulose fraction of sufficient quality for further use, with barley husks used as the raw material. An alkaline extraction was used to isolate the biopolymers by a process in which sodium dithionite replaced the traditional sodium borohydride as the reducing agent. The cellulose fraction was successfully transformed into nanocellulose by sulfuric acid hydrolysis, and the obtained hemicellulose (i.e., arabinoxylan) displayed carbohydrate composition characteristics similar to those previously reported in the literature for processes of extracting hemicellulose from barley husks. Using this methodology, both the cellulose and hemicellulose can be isolated in high quantities of dry material and used for transformation into new bio-based materials.
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| 25. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
Branching of hemicelluloses through an azetidinium salt ring-opening reaction
- 2016
-
In: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 428, s. 23-30
-
Journal article (peer-reviewed)abstract
- During the last century there has been a steady increase in the number of publications on practical applications of hemicellulose. Due to the water and moisture sensitivity, poor film-forming ability and lack of thermal processability most of the hemicelluloses need to be chemically modified prior to processing into materials. Within this study we present the results of azetidinium salts as a new functional group for conjugation to polysaccharides. The reactivity of three azetidinium salts on xylan, arabinoxylan and galactoglucomannan was investigated. Carbonyl groups were found to be favorable for the reaction with azetidinium salts and thus the glucuronic acid content in the hemicellulose determines the degree of substitution. TEMPO-oxidation of the hemicelluloses was done which successfully increased the degree of substitution. The highly reactive azetidinium salts are easily synthesized from secondary amines and epichlorohydrin and can be used as a new tool toward functionalization of hemicelluloses into the after sought properties.
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| 26. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
Crystalline Nanocellulose — Preparation, Modification, and Properties
- 2015
-
In: Cellulose - Fundamental Aspects and Current Trends. - 9789535122296 ; , s. 159-191
-
Book chapter (other academic/artistic)abstract
- Cellulose is a linear biopolymer found naturally in plant cells such as wood and cotton. It is the worlds most abundant polymer in nature and possesses properties such as good biocompatibility, low cost, low density, high strength, and good mechanical properties. By mechanical or chemical treatment, the cellulose fibers can be converted into cellulose nanofibers (CNFs) or cellulose nanocrystals (CNCs) that possess outstanding properties compared with the original cellulosic fiber but also when compared with other materials normally used as reinforcements in composite materials such as Kevlar or steel wires. This review will describe the nanocellulose materials preparation techniques and cellulose sources, chemical modification both on the crystalline surface and during hydrolysis and its many properties and its use in biocomposite materials. Nanocellulose in its different forms shows an increasing interest in application areas such as packaging, paper and paperboard, food industry, medical and hygiene products, paints, cosmetics, and optical sensors.
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| 27. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
Increased thermal stability of nanocellulose composites by functionalization of the sulfate groups on cellulose nanocrystals with azetidinium ions
- 2018
-
In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 135:10
-
Journal article (peer-reviewed)abstract
- Cellulose nanocrystals (CNCs) prepared via sulfuric acid hydrolysis are decorated with sulfate groups that yield a stable water suspension. To make the CNCs adaptable for use in composites, the hydroxyl groups on the surface are usually hydrophobized. In this article, an alternative hydrophobization method is described in which the sulfate groups are conjugated with azetidinium salts. The results of this study show that the sulfate groups can be functionalized with azetidinium salts and from thermal studies, it was discovered that the functionalization led to a 100 degrees C increase in thermal stability, compared with unmodified CNCs. The nanocomposites prepared by extrusion of CNC-coated low-density polyethylene powder displayed similar mechanical properties as the CNC-reference sample, but without the discoloration, due to the increased thermal stability. In conclusion, the azetidinium reagent reacts preferentially with sulfate groups, and this new type of chemical conversion of sulfate groups on polysaccharides will be beneficial in nanocomposite manufacturing. (C) 2017 Wiley Periodicals, Inc.
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| 28. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
Periodate oxidation of xylan-based hemicelluloses and its effect on their thermal properties
- 2018
-
In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 202, s. 280-287
-
Journal article (peer-reviewed)abstract
- Hemicellulose from pulp mill process water and crop residuals from food production often end up in waste streams or burnt for energy contribution. These waste products contain valuable biopolymers but lack many attributes needed for use in applications such as food and medical or consumer products. This study reports on an investigation of the periodate oxidation of hardwood xylan and arabinoxylan (AX) from wheat bran to produce materials with new functionalities. The study explores how to control the oxidation degree and describes structural differences between the two xylan-based polymers. For the xylan samples, the oxidation resulted in a lowering of the glass transition temperature (Tg), indicating a more flexible chain due to ring-opening of the xylan anhydro-sugar units. For the AX samples, the arabinose side-groups were instead oxidized, hindering oxidation on part of the xylose units, which resulted in a crosslinked network with an unchanged Tgbut reduced intrinsic viscosity.
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| 29. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
Thermoplastic and flexible films from arabinoxylan
- 2019
-
In: ACS Applied Polymer Materials. - : American Chemical Society (ACS). - 2637-6105. ; 1:6, s. 1443-1450
-
Journal article (peer-reviewed)abstract
- Current interest in replacing fossil-fuel-derivedpolymers and materials in favor of renewable materials is high.An inherent difficulty with the use of biomass-derivedpolysaccharides and hemicelluloses in this context, however,is their stiffness and lack offlowability at temperatures relevantfor thermal processing, which severely limits their capacity forthermal processing. Here, we present a modification thatenables a heat-processable arabinoxylan (AX). The modifica-tion involves a ring-opening oxidation to a dialdehyde withsubsequent reduction of the aldehydes to alcohol, to increasethe number of OH groups, followed by an etherification withhydrophobic alkyl chains. The modified AX was successfullycompression molded with heat intofilmswhich becomethermoplastic in behavior and highlyflexibleandflows at temperatures above 130°C. Thefilms are stretchable up to 200%,and their strength and strain deformation are controlled by the degree of oxidation and substitution of the AX polymer. Thesefindings are highly encouraging and open up the potential use of modified AX alone or as a composite in applications thatincludefilms, food packaging, and barriers via hot-melt processing techniques.
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| 30. |
- Börjesson, Mikaela, 1987, et al.
(author)
-
UV radiation of cellulose fibers and acrylic acid modified cellulose fibers for improved stiffness in paper
- 2015
-
In: BioResources. - : BioResources. - 1930-2126 .- 1930-2126. ; 10:2, s. 3056-3069
-
Journal article (peer-reviewed)abstract
- In this study, the strength and stiffness was measured on paper sheets with and without acryl ester functionalization grafted with UV-reactive molecules. Three different monomers with one, two, and three UV-reactive groups, respectively, were reacted with the unsaturated ester. The tri-functional monomer had the most influence on the strength properties of the three monomers and was added in concentrations of 5 to 20 wt% of paper (0.03-0.11 mol eq./AGU). The strength and stiffness properties were measured with tensile tests. An increase in elongation, tensile index, and Young's modulus was seen after irradiation. However, the paper sheets esterified with acrylic acid prior to radiation showed no improvement in stiffness compared to a non-treated paper. As a result, the esterification with acrylic acid to enhance the grafting effect did not have the ability to compensate for the loss in strength caused by the esterification treatment.
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| 31. |
- Chistov, Alexey A., et al.
(author)
-
Compounds based on 5-(perylen-3-ylethynyl)uracil scaffold: High activity against tick-borne encephalitis virus and non-specific activity against enterovirus A
- 2019
-
In: European Journal of Medicinal Chemistry. - : Elsevier BV. - 0223-5234 .- 1768-3254. ; 171, s. 93-103
-
Journal article (peer-reviewed)abstract
- Rigid amphipathic fusion inhibitors (RAFIs) are potent antivirals based on a perylene core linked with a nucleoside moiety. Sugar-free analogues of RAFIs, 5-(perylen-3-ylethynyl)uracil-1-acetic acid 1 and its amides 2, were synthesized using combined protection group strategy. Compounds 1 and 2 appeared to have low toxicity on porcine embryo kidney (PEK) or rhabdomiosarcoma (RD) cells together with remarkable activity against enveloped tick-borne encephalitis virus (TBEV): EC 50 values vary from 0.077 μM to subnanomolar range. Surprisingly, 3-pivaloyloxymethyl (Pom) protected precursors 7 and 8 showed even more pronounced activity. All the compounds showed no activity against several non-enveloped enteroviruses, except 4-hydroxybutylamides 2d,g, which inhibited the reproduction of enterovirus A71 with EC 50 50–100 μM, with a non-specific mode of action. The results suggest that the carbohydrate moiety of RAFI nucleosides does not play a crucial role in their antiviral action, and biological activity of the 5-(perylen-3-ylethynyl)uracil scaffold can be effectively modulated by substituents in positions 1 and 3. The high antiviral activity of these new compounds, coupled with low toxicity advocate their potential role in antiviral therapy.
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| 32. |
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| 33. |
- de la Motte, Hanna, 1983, et al.
(author)
-
Molecular characterization of hydrolyzed cationized nanocrystalline cellulose, cotton cellulose and softwood kraft pulp using high resolution 1D and 2D NMR
- 2011
-
In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 85:4, s. 738-746
-
Journal article (peer-reviewed)abstract
- Nanocrystalline cellulose, cotton linters and softwood kraft pulp were reacted with the cationic epoxide 2,3-epoxypropyltrimethyl ammonium chloride (EPTMAC) according to two different procedures, whereof one was a solvent and reagent minimizing spray technique. The samples were subjected to acid hydrolysis and characterized by solution-state nuclear magnetic resonance (NMR). The spectra were obtained using a 600 MHz cryoprobe NMR instrument. The use of ion exchange SPE-column chromatography enhanced the intensity of the peaks derived from the modified monosaccharide residues and opened for detailed NMR characterization at low degrees of substitution. In addition to a consistent 9 ppm change in the initial shifts of carbons adjacent to substituted hydroxyl groups, the NMR spectra proved that other neighboring atoms were affected by the substitution. Unlike nanocrystalline cellulose and cotton cellulose, the softwood kraft pulp cationized with the spray technique demonstrated a higher preference for 0-6 (83%), on the expense of O-2 substitution (16%).
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| 34. |
- de la Motte, Hanna, 1983, et al.
(author)
-
Regioselective cationization of cellulosic materials using an efficient solvent-minimizing spray-technique
- 2012
-
In: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 19:5, s. 1677-1688
-
Journal article (peer-reviewed)abstract
- Cationization of different cellulosic materials was successfully accomplished using an efficient solvent-minimizing spray-technique. The obtained materials were studied and evaluated in regard to reaction efficiency and regioselectivity using 1D and H-1-C-13 correlated 2D NMR experiments. The high consistencies and temperatures applied using the spray-technique resulted in reagent effective etherifications and shorter reaction times. The NMR spectra indicated that the spray-technique favors substitutions at position O-6, showing a regioselectivity of O-6 > O-2 > O-3 for softwood kraft pulp (SKP) and cotton linters. However, cationization of mercerized cellulose and dissolving pulp, using the spray-technique, demonstrated more efficient reactions compared to SKP and cotton, and a regioselectivity of O-6 a parts per thousand yen O-2 > O-3. Nanocrystalline cellulose showed the lowest reactivity and a regioselectivity of O-6 a parts per thousand
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| 35. |
- Deralia, Parveen Kumar, 1985, et al.
(author)
-
Hydrophobization of arabinoxylan with n-butyl glycidyl ether yields stretchable thermoplastic materials
- 2021
-
In: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130 .- 1879-0003. ; 188, s. 491-500
-
Journal article (peer-reviewed)abstract
- Hemicelluloses are regarded as one of the first candidates for the development of value-added materials due to their renewability, abundance, and functionality. However, because most hemicelluloses are brittle, they can only be processed as a solution and cannot be processed using industrial melt-based polymer processing techniques. In this study, arabinoxylan (AX) was hydrophobized by incorporating butyl glycidyl ether (BuGE) into the hydroxyl groups through the opening of the BuGE epoxide ring, yielding alkoxy alcohols with terminal ethers. The formed BuGE derivatives were melt processable and can be manufactured into stretchable thermoplastic films through compression molding, which has never been done before with hemicellulose modified in a single step. The structural and thermomechanical properties of the one-step synthesis approach were compared to those of a two-step synthesis with a pre-activation step to demonstrate its robustness. The strain at break for the one-step synthesized AX thermoplastic with 3 mol of BuGE is ≈200%. These findings suggest that thermoplastic polymers can be composited with hemicelluloses or that thermoplastic polymers made entirely of hemicelluloses can be designed as packaging and stretchable electronics supports.
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| 36. |
- Deralia, Parveen Kumar, 1985, et al.
(author)
-
Oxidation Level and Glycidyl Ether Structure Determine Thermal Processability and Thermomechanical Properties of Arabinoxylan-Derived Thermoplastics
- 2021
-
In: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 4:4, s. 3133-3144
-
Journal article (peer-reviewed)abstract
- Developing flexible, stretchable, and thermally processable materials for packaging and stretchable electronic applications from polysaccharide-based polymers contributes to the smooth transition of the fossil-based economy to the circular bioeconomy. We present arabinoxylan (AX)-based thermoplastics obtained by ring-opening oxidation and subsequent reduction (dA-AX) combined with hydrophobization with three different glycidyl ethers [n-butyl (BuGE), isopropyl (iPrGE), and 2-ethyl hexyl (EtHGE) glycidyl ether]. We also investigate the relationship between structural composition, thermal processing, and thermomechanical properties. BuGE- A nd iPrGE-etherified dA-AXs showed glass-transition temperatures (Tg) far below their degradation temperatures and gave thermoplastic materials when compression-molded at 140 °C. The BuGE (3 mol)-etherified dA-AX films at 19 and 31% oxidation levels show 244% (±42) and 267% (±72) elongation, respectively. In contrast, iPrGE-dA-AX samples with shorter and branched terminals in the side chains had a maximum of 60% (±19) elongation. No studies have reported such superior elongation of AX thermoplastic films and its relationship with molar substitution and Tg. These findings have implications on the strategic development of chemical modification routes using commercial polymer processing technologies and on fine-tuning structures and properties when specific polysaccharide-based polymers are used to engineer bio-based products for film, packaging, and substrates for stretchable electronic applications.
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| 37. |
- Deralia, Parveen Kumar, 1985, et al.
(author)
-
Side chains affect the melt processing and stretchability of arabinoxylan biomass-based thermoplastic films
- 2022
-
In: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 294
-
Journal article (peer-reviewed)abstract
- Hydrophobization of hemicellulose causes melt processing and makes them stretchable thermoplastics. Understanding how native and/or appended side chains in various hemicelluloses after chemical modification affect melt processing and material properties can help in the development of products for film packaging and substrates for stretchable electronics applications. Herein, we describe a one-step and two-step strategy for the fabrication of flexible and stretchable thermoplastics prepared by compression molding of two structurally different arabinoxylans (AX). For one-step synthesis, the n-butyl glycidyl ether epoxide ring was opened to the hydroxyl group, resulting in the introduction of alkoxide side chains. The first step in the two-step synthesis was periodate oxidation. Because the melt processability for AXs having low arabinose to xylose ratio (araf/xylp<0.5) have been limited, two structurally distinct AXs extracted from wheat bran (AXWB, araf/xylp = 3/4) and barley husk (AXBH, araf/xylp = 1/4) were used to investigate the effect of araf/xylp and hydrophobization on the melt processability and properties of the final material. Melt compression processability was achieved in AXBH derived samples. DSC and DMA confirmed that the thermoplastics derived from AXWB and AXBH had dual and single glass transition (Tg) characteristics, respectively, but the thermoplastics derived from AXBH had lower stretchability (maximum 160%) compared to the AXWB samples (maximum 300%). Higher araf/xylp values, and thus longer alkoxide side chains in AXWB-derived thermoplastics, explain the stretchability differences.
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| 38. |
- Duits, F. H., et al.
(author)
-
Synaptic proteins in CSF as potential novel biomarkers for prognosis in prodromal Alzheimer's disease
- 2018
-
In: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 10
-
Journal article (peer-reviewed)abstract
- Background: We investigated whether a panel of 12 potential novel biomarkers consisting of proteins involved in synapse functioning and immunity would be able to distinguish patients with Alzheimer's disease (AD) and patients with mild cognitive impairment (MCI) from control subjects. Methods: We included 40 control subjects, 40 subjects with MCI, and 40 subjects with AD from the Amsterdam Dementia Cohort who were matched for age and sex (age 65 +/- 5 years, 19 [48%] women). The mean follow-up of patients with MCI was 3 years. Two or three tryptic peptides per protein were analyzed in cerebrospinal fluid using parallel reaction monitoring mass spectrometry. Corresponding stable isotope-labeled peptides were added and used as reference peptides. Multilevel generalized estimating equations (GEEs) with peptides clustered per subject and per protein (as within-subject variables) were used to assess differences between diagnostic groups. To assess differential effects of individual proteins, we included the diagnosis x protein interaction in the model. Separate GEE analyses were performed to assess differences between stable patients and patients with progressive MCI (MCI-AD). Results: There was a main effect for diagnosis (p < 0.01) and an interaction between diagnosis and protein (p < 0.01). Analysis stratified according to protein showed higher levels in patients with MCI for most proteins, especially in patients with MCI-AD. Chromogranin A, secretogranin II, neurexin 3, and neuropentraxin 1 showed the largest effect sizes; beta values ranged from 0.53 to 0.78 for patients with MCI versus control subjects or patients with AD, and from 0.67 to 0.98 for patients with MCI-AD versus patients with stable MCI. In contrast, neurosecretory protein VGF was lower in patients with AD than in patients with MCI (beta = -0.93 [SE 0.22]) and control subjects (beta = 0.46 [SE 0.19]). Conclusions: Our results suggest that several proteins involved in vesicular transport and synaptic stability are elevated in patients with MCI, especially in patients with MCI progressing to AD dementia. This may reflect early events in the AD pathophysiological cascade. These proteins may be valuable as disease stage or prognostic markers in an early symptomatic stage of the disease.
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| 39. |
- Egan, Allyson C, et al.
(author)
-
The Sound of Interconnectivity; The European Vasculitis Society 2022 Report
- 2022
-
In: Kidney International Reports. - : Elsevier BV. - 2468-0249. ; 7:8, s. 1745-1757
-
Journal article (peer-reviewed)abstract
- The first European Vasculitis Society (EUVAS) meeting report was published in 2017. Herein, we report on developments in the past 5 years which were greatly influenced by the pandemic. The adaptability to engage virtually, at this critical time in society, embodies the importance of networks and underscores the role of global collaborations. We outline state-of-the-art webinar topics, updates on developments in the last 5 years, and proposals for agendas going forward. A host of newly reported clinical trials is shaping practice on steroid minimization, maintenance strategies, and the role of newer therapies. To guide longer-term strategies, a longitudinal 10-year study investigating relapse, comorbidity, malignancy, and survival rates is at an advanced stage. Disease assessment studies are refining classification criteria to differentiate forms of vasculitis more fully. A large international validation study on the histologic classification of anti-neutrophil cytoplasmic antibody (ANCA) glomerulonephritis, recruiting new multicenter sites and comparing results with the Kidney Risk Score, has been conducted. Eosinophilic granulomatosis with polyangiitis (EGPA) genomics offers potential pathogenic subset and therapeutic insights. Among biomarkers, ANCA testing is favoring immunoassay as the preferred method for diagnostic evaluation. Consolidated development of European registries is progressing with an integrated framework to analyze large clinical data sets on an unprecedented scale.
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| 40. |
- Eriksson, Maja, 1975, et al.
(author)
-
Comparing mono- and divalent DNA groove binding cyanine dyes--Binding geometries, dissociation rates, and fluorescence properties
- 2006
-
In: Biophysical Chemistry. - : Elsevier BV. - 1873-4200 .- 0301-4622. ; 122:3, s. 195-205
-
Journal article (peer-reviewed)abstract
- The unsymmetrical cyanine dyes BOXTO-PRO and BOXTO-MEE were derived from the DNA groove binder BOXTO, by adding a positively charged or a non-ionic hydrophilic tail to BOXTO, respectively. The main objective was to obtain more efficient DNA probes, for instance in electrophoresis and microscopy, by slowing down the dissociation of BOXTO from DNA. The interactions with mixed sequence DNA was studied with fluorescence and absorbance spectroscopy, stopped-flow dissociation and gel electrophoresis. Both the derivatives are groove bound as BOXTO, and have similar fluorescence properties when bound to mixed sequence DNA in free solution. BOXTO-PRO exhibits a slower dissociation than BOXTO from DNA, whereas the dissociation rate for BOXTO-MEE is faster and, unexpectedly independent of the ionic strength. During gel electrophoresis both BOXTO-PRO and BOXTO-MEE exhibit a faster dissociation rate than BOXTO. Still, BOXTO-PRO seems to be a good alternative as DNA probe, especially for applications in free solution where the dissociation is slower than for the corresponding intercalator TOPRO-1.
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| 41. |
- Eriksson, M., et al.
(author)
-
Time-resolved electrophoretic analysis of mobility shifts for dissociating DNA ligands
- 2005
-
In: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 26:3, s. 524-532
-
Journal article (peer-reviewed)abstract
- Intercalative binding of ligands to DNA can be demonstrated by helix unwinding, monitored by gel electrophoresis of supercoiled DNA, as electrophoretic mobility is sensitive to the topological DNA state. However, we show that an apparent lack of unwinding in an electrophoretic assay could be due to dissociation of the (intercalated) ligand during the analysis, rather than evidence for a nonintercalative mode of binding to DNA. Repetitive scanning during the electrophoresis ensures that release of the ligand during electrophoresis does not affect the measured degree of unwinding, based on the electrophoretic velocity being determined as a function of time. We use this assay to establish intercalation as a mode of binding to DNA for the cyanine dyes YO, YO-PRO as well as two enantiomeric forms of the ruthenium complexes [(phen)2 Ru(tatpp)Ru(phen)2]4+, and to support groove-binding for the new unsymmetrical cyanine dyes BOXTO and BOXTO-PRO. Groove-binding could be concluded from a lack of unwinding, because we could rule out that it is caused by release of the dye during the electrophoresis. The gel electrophoresis has the advantage over hydrodynamic techniques that much smaller sample amounts are required, and our time-resolved approach can be employed in all mobility-shift assays when applied to dissociating complexes.
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| 42. |
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| 43. |
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| 44. |
- Forsgren, Lilian, 1990, et al.
(author)
-
Composites with surface-grafted cellulose nanocrystals (CNC)
- 2019
-
In: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 54:4, s. 3009-3022
-
Journal article (peer-reviewed)abstract
- Hydroxyazetidinium salts were used to surface-modify cellulose nanocrystals (CNC) by grafting the salts onto the sulphate ester groups on the CNC surfaces. The grafting was confirmed by ζ-potential measurements and by the thermal degradation behaviour of the modified CNC. The thermal stability (onset of degradation) of the CNC was improved by the surface modification (almost 100 °C). Composites containing surface-modified or unmodified CNC (0.1, 1.0 and 10 wt%) with an ethylene-based copolymer as matrix were produced by compression moulding. The thermal stability of the composites was not, however, markedly improved by the surface grafting onto the CNC. It is suggested that this is due to a degrafting mechanism, associated with the alkaline character of the system, taking place at high temperatures. Model experiments indicated, however, that this did not occur at the conditions under which the composites were produced. Furthermore, in the case of a reference based on pH-neutralised polymeric system and modified CNC, an upward shift in the onset of thermal degradation of the composite was observed. The addition of the CNC to the polymer matrix had a strong influence of the mechanical performance. For example, the tensile modulus increased approximately three times for some systems when adding 10 wt% CNC. The surface grafting of the hydroxyazetidinium salts appeared mainly to affect, in a positive sense, the yield behaviour and ductility of the composites. The results of the mechanical testing are discussed in terms of interactions between the grafted units and the matrix material and between the grafted groups.
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| 45. |
- Forsgren, Lilian, 1990, et al.
(author)
-
Water-assisted extrusion and injection moulding of composites with surface-grafted cellulose nanocrystals – An upscaling study
- 2021
-
In: Composites Part B: Engineering. - : Elsevier BV. - 1359-8368. ; 208
-
Journal article (peer-reviewed)abstract
- The large-scale surface modification of cellulose nanocrystals (CNC) was carried out to produce CNC-containing composites, in a scale of 3 kg, using industrial-scale melt processing techniques such as twin-screw extrusion and injection moulding. Two different polymer matrices, ethylene-acrylic acid copolymer (EAA) and low-density polyethylene (LDPE), were reinforced with 10 wt% unmodified cellulose nanocrystals (CNC) or surface-treated CNC, where a 2-hydroxyproyl-N-diallyl group had been grafted onto the sulphate half-ester groups on the CNC surfaces. This was achieved by mixing an aqueous CNC dispersion and the polymer pellets directly in the twin-screw extruder followed by a second dry compounding step prior to shaping by injection moulding. The injection-moulded materials were characterized with respect to their mechanical properties and thermal stability. The addition of 10 wt % CNC resulted in all cases in an increase in the yield strength and stiffness by 50–100%, most significantly for the EAA based composites. There were indications of the presence of a stable interphase and a percolating network in the EAA-based materials, according to dynamic-mechanical measurements. A reduction in thermal stability was observed for the melt-processed samples containing diallyl-modified CNC and discoloration in the EAA based samples.
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| 46. |
- Fryknäs, Mårten, et al.
(author)
-
Screening for phenotype selective activity in multidrug resistant cells identifies a novel tubulin active agent insensitive to common forms of cancer drug resistance
- 2013
-
In: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 13, s. 374-
-
Journal article (peer-reviewed)abstract
- Background: Drug resistance is a common cause of treatment failure in cancer patients and encompasses a multitude of different mechanisms. The aim of the present study was to identify drugs effective on multidrug resistant cells. Methods: The RPMI 8226 myeloma cell line and its multidrug resistant subline 8226/Dox40 was screened for cytotoxicity in response to 3,000 chemically diverse compounds using a fluorometric cytotoxicity assay (FMCA). Follow-up profiling was subsequently performed using various cellular and biochemical assays. Results: One compound, designated VLX40, demonstrated a higher activity against 8226/Dox40 cells compared to its parental counterpart. VLX40 induced delayed cell death with apoptotic features. Mechanistic exploration was performed using gene expression analysis of drug exposed tumor cells to generate a drug-specific signature. Strong connections to tubulin inhibitors and microtubule cytoskeleton were retrieved. The mechanistic hypothesis of VLX40 acting as a tubulin inhibitor was confirmed by direct measurements of interaction with tubulin polymerization using a biochemical assay and supported by demonstration of G2/M cell cycle arrest. When tested against a broad panel of primary cultures of patient tumor cells (PCPTC) representing different forms of leukemia and solid tumors, VLX40 displayed high activity against both myeloid and lymphoid leukemias in contrast to the reference compound vincristine to which myeloid blast cells are often insensitive. Significant in vivo activity was confirmed in myeloid U-937 cells implanted subcutaneously in mice using the hollow fiber model. Conclusions: The results indicate that VLX40 may be a useful prototype for development of novel tubulin active agents that are insensitive to common mechanisms of cancer drug resistance.
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| 47. |
- Gobom, Johan, et al.
(author)
-
Alzheimer's Disease Biomarker Analysis Using Targeted Mass Spectrometry.
- 2024
-
In: Molecular & cellular proteomics : MCP. - 1535-9484. ; 23:2
-
Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) is characterized by several neuropathological changes, mainly extracellular amyloid aggregates (plaques), intraneuronal inclusions of phosphorylated tau (tangles), as well as neuronal and synaptic degeneration, accompanied by tissue reactions to these processes (astrocytosis and microglial activation) that precede neuronal network disturbances in the symptomatic phase of the disease. A number of biomarkers for these brain tissue changes have been developed, mainly using immunoassays. In this review, we discuss how targeted mass spectrometry (TMS) can be used to validate and further characterize classes of biomarkers reflecting different AD pathologies, such as tau- and amyloid-beta pathologies, synaptic dysfunction, lysosomal dysregulation, and axonal damage, and the prospect of using TMS to measure these proteins in clinical research and diagnosis. TMS advantages and disadvantages in relation to immunoassays are discussed, and complementary aspects of the technologies are discussed.
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| 48. |
- Goel, Suchi, et al.
(author)
-
RIFINs are adhesins implicated in severe Plasmodium falciparum malaria
- 2015
-
In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 21:4, s. 314-317
-
Journal article (peer-reviewed)abstract
- Rosetting is a virulent Plasmodium falciparum phenomenon associated with severe malaria. Here we demonstrate that P. falciparum-encoded repetitive interspersed families of polypeptides (RIFINs) are expressed on the surface of infected red blood cells (iRBCs), bind to RBCs-preferentially of blood group A-to form large rosettes and mediate microvascular binding of iRBCs. We suggest that RIFINs have a fundamental role in the development of severe malaria and thereby contribute to the varying global distribution of ABO blood groups in the human population.
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| 49. |
- Gullbo, Joachim, et al.
(author)
-
Phenotype-based drug screening in primary ovarian carcinoma cultures identifies intracellular iron depletion as a promising strategy for cancer treatment
- 2011
-
In: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952 .- 1356-1839 .- 1873-2968. ; 82:2, s. 139-147
-
Journal article (peer-reviewed)abstract
- Primary cultures of patient tumor cells (PCPTC) have been used for prediction of diagnosis-specific activity and individual patient response to anticancer drugs, but have not been utilized as a model for identification of novel drugs in high throughput screening. In the present study, ovarian carcinoma cells from three patients were tested in response to a library of 3000 chemically diverse compounds. Eight hits were retrieved after counter screening using normal epithelial cells, and one of the two structurally related hit compounds was selected for further preclinical evaluation. This compound, designated VLX 50, demonstrated a broad spectrum of activity when tested in a panel of PCPTCs representing different forms of leukemia and solid tumors and displayed a high tumor to normal cell activity. VLX 50 induced delayed cell death with some features of classical apoptosis. Significant in vivo activity was confirmed on primary cultures of human ovarian carcinoma cells in mice using the hollow fiber model. Mechanistic exploration was performed using gene expression analysis of drug exposed tumor cells to generate a drug-specific signature. This query signature was analyzed using the Gene Set Enrichment Analysis and the Connectivity Map database. Strong connections to hypoxia inducible factor 1 and iron chelators were retrieved. The mechanistic hypothesis of intracellular iron depletion leading to hypoxia signaling was confirmed by a series of experiments. The results indicate the feasibility of using PCPTC for cancer drug screening and that intracellular iron depletion could be a potentially important strategy for cancer therapy.
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| 50. |
- Gustafsson, Björn, 1970, et al.
(author)
-
A tetrameric copper(I) alkoxide with a pi-tethered ligand: 2-allyl-6-methylphenoxocopper(I)
- 2002
-
In: Journal of Organometallic Chemistry. - 0022-328X. ; 649:2, s. 204-208
-
Journal article (peer-reviewed)abstract
- The complex 2-allyl-6-methylphenoxocopper(I) has been prepared by reaction between mesitylcopper(I) and 2-allyl-6-methylphenol. Crystallographic studies show that the compound is tetrameric with a distorted cubane-type copper(I)-oxygen core, and with additional pi-coordination of the ligand to copper through the alkene functionality (nu(C=C)=1520 cm(-1)). The ligands thus act both as chelates and as bridges between adjacent copper(l) centres. Copper(l) exhibits trigonal pyramidal coordination geometry with Cu-C distances to the C=C group of 1.976(9) and 2.017(11) Angstrom and Cu-O distances of 1.973(6), 2.021(6) and 2.577(6) Angstrom, respectively.
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