Umeå University's logo

umu.sePublications
Change search
Refine search result
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Emilsson, Gustav
    et al.
    Röder, Evelyn
    Malekian, Bita
    Xiong, Kunli
    Manzi, John
    Tsai, Feng-Ching
    Cho, Nam-Joon
    Bally, Marta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Dahlin, Andreas
    Nanoplasmonic Sensor Detects Preferential Binding of IRSp53 to Negative Membrane Curvature2019In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 1Article in journal (Refereed)
    Abstract [en]

    Biosensors based on plasmonic nanostructures are widely used in various applications and benefit from numerous operational advantages. One type of application where nanostructured sensors provide unique value in comparison with, for instance, conventional surface plasmon resonance, is investigations of the influence of nanoscale geometry on biomolecular binding events. In this study, we show that plasmonic "nanowells" conformally coated with a continuous lipid bilayer can be used to detect the preferential binding of the insulin receptor tyrosine kinase substrate protein (IRSp53) I-BAR domain to regions of negative surface curvature, i.e., the interior of the nanowells. Two different sensor architectures with and without an additional niobium oxide layer are compared for this purpose. In both cases, curvature preferential binding of IRSp53 (at around 0.025 nm(-1) and higher) can be detected qualitatively. The high refractive index niobium oxide influences the near field distribution and makes the signature for bilayer formation less clear, but the contrast for accumulation at regions of negative curvature is slightly higher. This work shows the first example of analyzing preferential binding of an average-sized and biologically important protein to negative membrane curvature in a label-free manner and in real-time, illustrating a unique application for nanoplasmonic sensors.

    Download full text (pdf)
    fulltext
  • 2. Kamran, Muhammad
    et al.
    Khan, Abdul L.
    Ali, Liaqat
    Hussain, Javid
    Waqas, Muhammad
    Al-Harrasi, Ahmed
    Imran, Qari Muhammad
    School of Applied Biosciences, Kyungpook National University, Daegu, South Korea.
    Kim, Yoon-Ha
    Kang, Sang-Mo
    Yun, Byung-Wook
    Hydroquinone; a novel bioactive compound from plant-derived smoke can cue seed germination of lettuce2017In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 5, article id 30Article in journal (Refereed)
    Abstract [en]

    Plant-derived smoke has been known to play an important role in distribution and growth of vegetation. Using a proficiently designed furnace, we extracted smoke from the leaves of four plant viz. Helianthus annuus,Aloe vera,Ginkgo biloba, and Cymbopogon jwarancusa. Smoke dilutions obtained from these plants were obtained in different concentrations to identify potential lettuce growth promoting smoke solution. Results revealed that smoke obtained from G. biloba significantly enhanced the lettuce seed germination. This solution was then partitioned into ethyl acetate, dichloromethane, n-hexane, chloroform and ether fractions. Ethyl acetate fraction was found to be potent to enhance seed germination. This fraction was subjected to column chromatography and spectroscopic techniques to obtain compound 1. This compound was identified as hydroquinone using 1D and 2D NMR techniques. At low concentrations (5, 10, and 20 ppm), compound 1 enhanced the lettuce seed germination; however, higher concentrations inhibited its growth as compared to control.

    Download full text (pdf)
    fulltext
  • 3. KjÊrvik, Marit
    et al.
    Ramstedt, Madeleine
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schwibbert, Karin
    Dietrich, Paul M.
    Unger, Wolfgang E. S.
    Comparative Study of NAP-XPS and Cryo-XPS for the Investigation of Surface Chemistry of the Bacterial Cell-Envelope2021In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 9, article id 666161Article in journal (Refereed)
    Abstract [en]

    Bacteria generally interact with the environment via processes involving their cell-envelope. Thus, techniques that may shed light on their surface chemistry are attractive tools for providing an understanding of bacterial interactions. One of these tools is Al Kα-excited photoelectron spectroscopy (XPS) with its estimated information depth of <10 nm. XPS-analyses of bacteria have been performed for several decades on freeze-dried specimens in order to be compatible with the vacuum in the analysis chamber of the spectrometer. A limitation of these studies has been that the freeze-drying method may collapse cell structure as well as introduce surface contaminants. However, recent developments in XPS allow for analysis of biological samples at near ambient pressure (NAP-XPS) or as frozen hydrated specimens (cryo-XPS) in vacuum. In this work, we have analyzed bacterial samples from a reference strain of the Gram-negative bacterium Pseudomonas fluorescens using both techniques. We compare the results obtained and, in general, observe good agreement between the two techniques. Furthermore, we discuss advantages and disadvantages with the two analysis approaches and the output data they provide. XPS reference data from the bacterial strain are provided, and we propose that planktonic cells of this strain (DSM 50090) are used as a reference material for surface chemical analysis of bacterial systems.

    Download full text (pdf)
    fulltext
  • 4. Salminen, Eero
    et al.
    Virtanen, Pasi
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal2014In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 2, article id 3Article in journal (Refereed)
    Abstract [en]

    The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

    Download full text (pdf)
    fulltext
  • 5.
    Sarmad, Shokat
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Zafarani-Moattar, Mohammed Taghi
    Nikjoo, Dariush
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry & Reaction Engineering, John Gadolin Process Chemistry Centre, Åbo Akademi University, Turku, Finland.
    How Different Electrolytes Can Influence the Aqueous Solution Behavior of 1-Ethyl-3-Methylimidazolium Chloride: A Volumetric, Viscometric, and Infrared Spectroscopy Approach2020In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 8, article id 593786Article in journal (Refereed)
    Abstract [en]

    The density, sound velocity, and viscosity of 1-ethyl-3-methylimidazolium chloride [C2mim]Cl in pure water and aqueous solutions of some electrolytes such as potassium chloride, potassium carbonate, and potassium phosphate (weight fraction of salt fixed at ws = 0. 11) have been measured over a wide range of temperatures from 298.15 to 318.15 K. The obtained experimental data have been used to compute various volumetric, compressibility, and viscometric parameters, e.g., apparent molar properties, limiting apparent molar and transfer properties. The co-sphere overlap model was employed to describe the dominant intermolecular interactions in the ternary solutions. Additionally, the structure making/breaking nature of the [C2mim]Cl in the ternary solutions has been discussed in terms of Hepler's constant and the temperature derivative of viscosity B-coefficient (dB/dT). The activation free energy of solvent and solute, activation enthalpy, and activation entropy have been calculated by the application of transition state theory. The calculated parameters have been interpreted in the sense of solvent-solute and solute-solute interactions. The Fourier transform infrared (FTIR) studies also have been done for the studied systems. Volumetric, acoustic, viscometric, and spectroscopic studies can render some evidence and help to understand the aqueous solution behavior of ionic liquids.

    Download full text (pdf)
    fulltext
  • 6.
    Shchukarev, Andrey
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Backman, Emelie
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Watts, Samuel
    Biointerfaces Lab, Empa, SwissFederal Laboratories for Material Science and Technology, St. Gallen, Switzerland.
    Salentinig, Stefan
    Department of Chemistry, FribourgUniversity, Fribourg, Switzerland.
    Urban, Constantin F.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Ramstedt, Madeleine
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Applying Cryo-X-ray Photoelectron Spectroscopy to Study the Surface Chemical Composition of Fungi and Viruses2021In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 9, article id 666853Article in journal (Refereed)
    Abstract [en]

    Interaction between microorganisms and their surroundings are generally mediated via the cell wall or cell envelope. An understanding of the overall chemical composition of these surface layers may give clues on how these interactions occur and suggest mechanisms to manipulate them. This knowledge is key, for instance, in research aiming to reduce colonization of medical devices and device-related infections from different types of microorganisms. In this context, X-ray photoelectron spectroscopy (XPS) is a powerful technique as its analysis depth below 10 nm enables studies of the outermost surface structures of microorganism. Of specific interest for the study of biological systems is cryogenic XPS (cryo-XPS). This technique allows studies of intact fast-frozen hydrated samples without the need for pre-treatment procedures that may cause the cell structure to collapse or change due to the loss of water. Previously, cryo-XPS has been applied to study bacterial and algal surfaces with respect to their composition of lipids, polysaccharides and peptide (protein and/or peptidoglycan). This contribution focuses onto two other groups of microorganisms with widely different architecture and modes of life, namely fungi and viruses. It evaluates to what extent existing models for data treatment of XPS spectra can be applied to understand the chemical composition of their very different surface layers. XPS data from model organisms as well as reference substances representing specific building blocks of their surface were collected and are presented. These results aims to guide future analysis of the surface chemical composition of biological systems.

    Download full text (pdf)
    fulltext
  • 7.
    Shukla, Shashi Kant
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry and Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Use of Ionic Liquids in Protein and DNA Chemistry2020In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 8, p. 1-23, article id 598662Article, review/survey (Refereed)
    Abstract [en]

    Ionic liquids (ILs) have been receiving much attention as solvents in various areas of biochemistry because of their various beneficial properties over the volatile solvents and ILs availability in myriad variants (perhaps as many as 10(8)) owing to the possibility of paring one cation with several anions and vice-versa as well as formulations as zwitterions. Their potential as solvents lies in their tendency to offer both directional and non-directional forces toward a solute molecule. Because of these forces, ionic liquids easily undergo intermolecular interactions with a range of polar/non-polar solutes, including biomolecules such as proteins and DNA. The interaction of genomic species in aqueous/non-aqueous states assists in unraveling their structure and functioning, which have implications in various biomedical applications. The charge density of ionic liquids renders them hydrophilic and hydrophobic, which retain intact over long-range of temperatures. Their ability in stabilizing or destabilizing the 3D-structure of a protein or the double-helical structure of DNA has been assessed superior to the water and volatile organic solvents. The aptitude of an ion in influencing the structure and stability of a native protein depends on their ranking in the Hofmeister series. However, at several instances, a reverse Hofmeister ordering of ions and specific ion-solute interaction has been observed. The capability of an ionic liquid in terms of the tendency to promote the coiling/uncoiling of DNA structure is noted to rely on the basicity, electrostatic interaction, and hydrophobicity of the ionic liquid in question. Any change in the DNA's double-helical structure reflects a change in its melting temperature (T-m), compared to a standard buffer solution. These changes in DNA structure have implications in biosensor design and targeted drug-delivery in biomedical applications. In the current review, we have attempted to highlight various aspects of ionic liquids that influence the structure and properties of proteins and DNA. In short, the review will address the issues related to the origin and strength of intermolecular interactions, the effect of structural components, their nature, and the influence of temperature, pH, and additives on them.

    Download full text (pdf)
    fulltext
  • 8.
    Wang, Tianxiao
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Li, Menghong
    Umeå University, Faculty of Medicine, Department of Odontology.
    Gu, Ziyan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Qu, Chengjuan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Segervald, Jonas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Salh, Roushdey
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Wågberg, Thomas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Wang, Jia
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Kou, Wen
    Umeå University, Faculty of Medicine, Department of Odontology.
    Fluoride releasing in polymerblends of poly(ethylene oxide) and poly(methyl methacrylate)2024In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 12, article id 1356029Article in journal (Refereed)
    Abstract [en]

    Introduction: Polymethyl methacrylate is a polymer commonly used in clinicaldentistry, including denture bases, occlusal splints and orthodontic retainers.

    Methods: To augment the polymethyl methacrylate-based dental appliances incounteracting dental caries, we designed a polymer blend film composed ofpolymethyl methacrylate and polyethylene oxide by solution casting and addedsodium fluoride.

    Results: Polyethylene oxide facilitated the dispersion of sodium fluoride,decreased the surface average roughness, and positively influenced thehydrophilicity of the films. The blend film made of polymethyl methacrylate,polyethylene oxide and NaF with a mass ratio of 10: 1: 0.3 showed sustainedrelease of fluoride ions and acceptable cytotoxicity. Antibacterial activity of all thefilms to Streptococcus mutans was negligible.

    Discussion: This study demonstrated that the polymer blends of polyethyleneoxide and polymethyl methacrylate could realize the relatively steady release offluoride ions with high biocompatibility. This strategy has promising potential toendow dental appliances with anti-cariogenicity.

    Download full text (pdf)
    fulltext
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf