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Dahle S, Žigon J, Fink R. Cold plasma for sustainable control of hygienically relevant biofilms. The interaction of plasma distance and exposure time. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2024; 34:340-354. [PMID: 36436211 DOI: 10.1080/09603123.2022.2149710] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
This study aimed to analyse the efficacy of a new cold plasma device adapted for treatment with a low power consumption . We tested the reduction of bacterial cells in biofilms of E. coli, S. aureus and P. aeruginosa. . The results show significant differences between bacterial cells, suggesting that Gramme-positive S. aureus is less susceptible to plasma treatment than Gramme-negative E. coli and P. aeruginosa. Increasing the exposure time and decreasing the distance decreases the number of cells in the biofilm. However, the combination of close distance and long exposure time resulted in synergistic effects. We demonstrated a reduction of up to 6.6 log CFU cm2 for E. coli at 1 mm and an exposure time of 60 seconds. All these indicate that the new cold plasma jet device can be an important key to ensuring hygiene and numerous applications in medicine and engineering are possible.
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Affiliation(s)
- Sebastian Dahle
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Jure Žigon
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rok Fink
- Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia
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Matwiej Ł, Wieruszewski M, Wiaderek K, Pałubicki B. Elements of Designing Upholstered Furniture Sandwich Frames Using Finite Element Method. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6084. [PMID: 36079465 PMCID: PMC9458000 DOI: 10.3390/ma15176084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
This paper presents an approach to the design of an upholstered furniture frame using the finite element method and empirical studies. Three-dimensional discrete models of upholstered furniture frames were developed taking into account orthotropic properties of solid pine wood (Pinus sylvestris L.) without and with details strengthening their structure in the form of glue joints and upholstery staples. Using the CAE Autodesk Inventor Nastran finite element method, linear static analyses were performed by simulating normative loading. The finite element method was performed considering the experimentally determined stiffness coefficients of the PCAC adhesive and staple joints. As a result, stress, displacement, and equivalent strain distributions were obtained for upholstered furniture frame models with stapled corner joints. The deformation and strength behavior of the upholstered furniture frames was improved by reinforcing with a wood strip. A new approach to the design of upholstered furniture frame frames using the FEM method with stapled component connections was developed and tested. The results of the study can be applied in the optimization of upholstered furniture construction.
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Liu SJ, Liao SC. Surface Modification of Bamboo Charcoal by O 2 Plasma Treatment and UV-Grafted Thermo-Sensitive AgNPs Hydrogel to Improve Antibacterial Properties in Biomedical Application. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2697. [PMID: 34685136 PMCID: PMC8537071 DOI: 10.3390/nano11102697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/04/2021] [Accepted: 10/08/2021] [Indexed: 12/28/2022]
Abstract
With the advancement of science and modern medical technology, more and more medical materials and implants are used in medical treatment and to improve human life. The safety of invasive medical materials and the prevention of infection are gradually being valued. Therefore, avoiding operation failure or wound infection and inflammation caused by surgical infection is one of the most important topics in current medical technology. Silver nanoparticles (AgNPs) have minor irritation and toxicity to cells and have a broad-spectrum antibacterial effect without causing bacterial resistance and other problems. They are also less toxic to the human body. Bamboo charcoal (BC) is a bioinert material with a porous structure, light characteristics, and low density, like bone quality. It can be used as a lightweight bone filling material. However, it does not have any antibacterial function. This study synthesized AgNPs under the ultraviolet (UV) photochemical method by reducing silver nitrate with sodium citrate. The formation and distribution of AgNPs were confirmed by UV-visible spectroscopy and X-ray diffraction measurement (XRD). The BC was treated by O2 plasma to increase the number of polar functional groups on the surface. Then, UV light-induced graft polymerization of N-isopropyl acrylamide (NIPAAm) and AgNPs were applied onto the BC to immobilize thermos-/antibacterial composite hydrogels on the BC surface. The structures and properties of thermos-/antibacterial composite hydrogel-modified BC surface were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectrum (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results show that thermos-/antibacterial composite hydrogels were then successfully grafted onto BC. SEM observations showed that the thermos-/antibacterial composite hydrogels formed a membrane structure between the BC. The biocompatibility of the substrate was evaluated by Alamar Blue cell viability assay and antibacterial test in vitro.
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Affiliation(s)
- Shih-Ju Liu
- Design and Materials for Medical Equipment and Devices, Da-Yeh University Changhua, Changhua 515006, Taiwan;
| | - Shu-Chuan Liao
- Department of Biomedical Engineering, Da-Yeh University Changhua, Changhua 515006, Taiwan
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Buschmann B, Henke K, Talke D, Saile B, Asshoff C, Bunzel F. Additive Manufacturing of Wood Composite Panels for Individual Layer Fabrication (ILF). Polymers (Basel) 2021; 13:3423. [PMID: 34641238 PMCID: PMC8511984 DOI: 10.3390/polym13193423] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 11/16/2022] Open
Abstract
The renewable resource, wood, is becoming increasingly popular as a feedstock material for additive manufacturing (AM). It can help make those processes more affordable and reduce their environmental impact. Individual layer fabrication (ILF) is a novel AM process conceived for structural applications. In ILF, parts are formed by laminating thin, individually contoured panels of wood composites which are fabricated additively by binder jetting. The individual fabrication of single panels allows the application of mechanical pressure in manufacturing those board-like elements, leading to a reduction of binder contend and an increase of mechanical strength. In this paper, the ILF process is described in detail, geometric and processing limitations are identified, and the mechanical properties of the intermediate product (panels) are presented. It is shown that the thickness of panels significantly influences the geometric accuracy. Wood composite panels from spruce chips and pMDI adhesive showed flexural strengths between 24.00 and 52.45 MPa with adhesive contents between 6.98 and 17.00 wt %. Thus, the panels meet the mechanical requirements for usage in the European construction industry. Additionally, they have significantly lower binder contents than previously investigated additively manufactured wood composites.
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Affiliation(s)
- Birger Buschmann
- Chair of Timber Structures and Building Construction, TUM School of Engineering and Design, Technical University of Munich, Arcisstraße 21, 80333 Munich, Germany; (K.H.); (D.T.); (B.S.)
| | - Klaudius Henke
- Chair of Timber Structures and Building Construction, TUM School of Engineering and Design, Technical University of Munich, Arcisstraße 21, 80333 Munich, Germany; (K.H.); (D.T.); (B.S.)
| | - Daniel Talke
- Chair of Timber Structures and Building Construction, TUM School of Engineering and Design, Technical University of Munich, Arcisstraße 21, 80333 Munich, Germany; (K.H.); (D.T.); (B.S.)
| | - Bettina Saile
- Chair of Timber Structures and Building Construction, TUM School of Engineering and Design, Technical University of Munich, Arcisstraße 21, 80333 Munich, Germany; (K.H.); (D.T.); (B.S.)
| | - Carsten Asshoff
- Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut WKI, Bienroder Weg 54E, 38108 Brunswick, Germany; (C.A.); (F.B.)
| | - Frauke Bunzel
- Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut WKI, Bienroder Weg 54E, 38108 Brunswick, Germany; (C.A.); (F.B.)
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Levchenko I, Xu S, Baranov O, Bazaka O, Ivanova EP, Bazaka K. Plasma and Polymers: Recent Progress and Trends. Molecules 2021; 26:molecules26134091. [PMID: 34279431 PMCID: PMC8271681 DOI: 10.3390/molecules26134091] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 02/06/2023] Open
Abstract
Plasma-enhanced synthesis and modification of polymers is a field that continues to expand and become increasingly more sophisticated. The highly reactive processing environments afforded by the inherently dynamic nature of plasma media are often superior to ambient or thermal environments, offering substantial advantages over other processing methods. The fluxes of energy and matter toward the surface enable rapid and efficient processing, whereas the charged nature of plasma-generated particles provides a means for their control. The range of materials that can be treated by plasmas is incredibly broad, spanning pure polymers, polymer-metal, polymer-wood, polymer-nanocarbon composites, and others. In this review, we briefly outline some of the recent examples of the state-of-the-art in the plasma-based polymer treatment and functionalization techniques.
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Affiliation(s)
- Igor Levchenko
- Plasma Sources and Application Centre, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore;
- Correspondence: (I.L.); (K.B.)
| | - Shuyan Xu
- Plasma Sources and Application Centre, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore;
| | - Oleg Baranov
- Faculty of Aircraft Engines, National Aerospace University, 61070 Kharkiv, Ukraine;
| | - Olha Bazaka
- School of Science, RMIT University, P.O. Box 2476, Melbourne, VIC 3001, Australia; (O.B.); (E.P.I.)
| | - Elena P. Ivanova
- School of Science, RMIT University, P.O. Box 2476, Melbourne, VIC 3001, Australia; (O.B.); (E.P.I.)
| | - Kateryna Bazaka
- Plasma Sources and Application Centre, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore;
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
- School of Engineering, The Australian National University, Canberra, ACT 2601, Australia
- Correspondence: (I.L.); (K.B.)
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Discharge Plasma Treatment as an Efficient Tool for Improved Poly(lactide) Adhesive-Wood Interactions. MATERIALS 2021; 14:ma14133672. [PMID: 34209330 PMCID: PMC8269815 DOI: 10.3390/ma14133672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/19/2021] [Accepted: 06/29/2021] [Indexed: 11/16/2022]
Abstract
Poly(lactide) (PLA) films obtained by thermoforming or solution-casting were modified by diffuse coplanar surface barrier discharge plasma (300 W and 60 s). PLA films were used as hot-melt adhesive in joints in oak wood. It was demonstrated that lap shear strength increased from 3.4 to 8.2 MPa, respectively, for the untreated and plasma-treated series. Pull-off tests performed on particleboard for the untreated and treated PLA films showed 100% cohesive failure. Pull-off strength tests on solid oak demonstrated adhesion enhancement from 3.3 MPa with the adhesion failure mode to 6.6 MPa with the cohesion failure mode for untreated and treated PLA. XPS revealed that carbonyl oxygen content increased by two-to-three-fold, which was confirmed in the Fourier-transform infrared spectroscopy experiments of the treated PLA. The water contact angle decreased from 66.4° for the pristine PLA to 49.8° after treatment. Subsequently, the surface free energy increased from 47.9 to 61.05 mJ/m2. Thus, it was clearly proven that discharge air plasma can be an efficient tool to change surface properties and to strengthen adhesive interactions between PLA and woody substrates.
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