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Furgier, V., Root, A., Heinmaa, I., Zamani, A. & Åkesson, D. (2024). Development and Characterisation of Composites Prepared from PHBV Compounded with Organic Waste Reinforcements, and Their Soil Biodegradation. Materials, 17(3), Article ID 768.
Open this publication in new window or tab >>Development and Characterisation of Composites Prepared from PHBV Compounded with Organic Waste Reinforcements, and Their Soil Biodegradation
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2024 (English)In: Materials, E-ISSN 1996-1944, Vol. 17, no 3, article id 768Article in journal (Refereed) Published
Abstract [en]

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biobased and biodegradable polymer. This polymer is considered promising, but it is also rather expensive. The objective of this study was to compound PHBV with three different organic fillers considered waste: human hair waste (HHW), sawdust (SD) and chitin from shrimp shells. Thus, the cost of the biopolymer is reduced, and, at the same time, waste materials are valorised into something useful. The composites prepared were characterised by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile strength and scanning electron micrograph (SEM). Tests showed that chitin and HHW did not have a reinforcing effect on tensile strength while the SD increased the tensile strength at break to a certain degree. The biodegradation of the different composites was evaluated by a soil burial test for five months. The gravimetric test showed that neat PHBV was moderately degraded (about 5% weight loss) while reinforcing the polymer with organic waste clearly improved the biodegradation. The strongest biodegradation was achieved when the biopolymer was compounded with HHW (35% weight loss). The strong biodegradation of HHW was further demonstrated by characterisation by Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR). Characterisation by SEM showed that the surfaces of the biodegraded samples were eroded.

Keywords
PHBV, biocomposite, biodegradation, sawdust, hair waste, chitin
National Category
Polymer Technologies
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-31632 (URN)10.3390/ma17030768 (DOI)001160406300001 ()
Available from: 2024-02-27 Created: 2024-02-27 Last updated: 2024-02-27
Vu, H. D., Mahboubi, A., Root, A., Heinmaa, I., Taherzadeh, M. J. & Åkesson, D. (2023). Application of Immersed Membrane Bioreactor for Semi-Continuous Production of Polyhydroxyalkanoates from Organic Waste-Based Volatile Fatty Acids. Membranes, 13(6), Article ID 569.
Open this publication in new window or tab >>Application of Immersed Membrane Bioreactor for Semi-Continuous Production of Polyhydroxyalkanoates from Organic Waste-Based Volatile Fatty Acids
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2023 (English)In: Membranes, ISSN 2077-0375, E-ISSN 2077-0375, Vol. 13, no 6, article id 569Article in journal (Refereed) Published
Abstract [en]

Volatile fatty acids (VFAs) appear to be an economical carbon feedstock for the cost-effective production of polyhydroxyalkanoates (PHAs). The use of VFAs, however, could impose a drawback of substrate inhibition at high concentrations, resulting in low microbial PHA productivity in batch cultivations. In this regard, retaining high cell density using immersed membrane bioreactor (iMBR) in a (semi-) continuous process could enhance production yields. In this study, an iMBR with a flat-sheet membrane was applied for semi-continuous cultivation and recovery of Cupriavidus necator in a bench-scale bioreactor using VFAs as the sole carbon source. The cultivation was prolonged up to 128 h under an interval feed of 5 g/L VFAs at a dilution rate of 0.15 (d−1), yielding a maximum biomass and PHA production of 6.6 and 2.8 g/L, respectively. Potato liquor and apple pomace-based VFAs with a total concentration of 8.8 g/L were also successfully used in the iMBR, rendering the highest PHA content of 1.3 g/L after 128 h of cultivation. The PHAs obtained from both synthetic and real VFA effluents were affirmed to be poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a crystallinity degree of 23.8 and 9.6%, respectively. The application of iMBR could open an opportunity for semi-continuous production of PHA, increasing the feasibility of upscaling PHA production using waste-based VFAs. 

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
biopolymer, immersed membrane reactor, polyhydroxyalkanoates, volatile fatty acids, Bioconversion, Bioreactors, Carbon, Cost effectiveness, Crystallinity, Effluents, Carbon feedstock, Continuous production, Cost-effective production, Immersed membrane, Immersed membrane bioreactors, Membrane reactor, Organic wastes, Semi-continuous, Biopolymers
National Category
Other Industrial Biotechnology
Research subject
Resource Recovery; Resource Recovery
Identifiers
urn:nbn:se:hb:diva-30312 (URN)10.3390/membranes13060569 (DOI)001014724600001 ()2-s2.0-85164028978 (Scopus ID)
Available from: 2023-08-14 Created: 2023-08-14 Last updated: 2024-02-01Bibliographically approved
Kopf, S., Åkesson, D., Hakkarainen, M. & Skrifvars, M. (2023). Effect of hydroxyapatite particle morphology on as-spun poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/hydroxyapatite composite fibers. Results in Materials, 20, Article ID 100465.
Open this publication in new window or tab >>Effect of hydroxyapatite particle morphology on as-spun poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/hydroxyapatite composite fibers
2023 (English)In: Results in Materials, ISSN 2590-048X, Vol. 20, article id 100465Article in journal (Refereed) Published
Abstract [en]

Hydroxyapatite (HA) has shown very promising results in hard tissue engineering because of its similarity to bone and hence the capability to promote osteogenic differentiation. While the bioactivity of HA is uncontested, there are still uncertainties about the most suitable hydroxyapatite particle shapes and sizes for textile scaffolds. This study investigates the influence of the shape and size of HA particles on as spun fibers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and HA, their mechanical and thermal properties as well as their influence on the fiber degradation in simulated blood matrix and their capability to mineralize in simulated body fluid. The key findings were that the different HA particles’ size does not affect the melting temperature and still maintains a thermal stability suitable for fiber production. Tensile testing revealed decreased mechanical properties for PHBV/HA as spun fibers, independently of the particle morphology. However, HA particles with 30 nm in width and 100 nm in length at 1 wt% HA loading achieved the highest tenacity and elongation at break amongst all composite fibers with HA. Besides, the Ca/P ratio of their mineralization in simulated body fluid is the closest to the one of mineralized human bone, indicating the most promising bioactivity results of all HA particles studied.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Tissue engineering, Hydroxyapatite (HA), Particle size, Melt spinning, Fiber, Bionanocomposite, Biomimetic, Melt extrusion, Mechanical properties, Degradation, Thermal properties
National Category
Polymer Technologies
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-30988 (URN)10.1016/j.rinma.2023.100465 (DOI)2-s2.0-85173948487 (Scopus ID)
Funder
University of Borås
Available from: 2023-12-12 Created: 2023-12-12 Last updated: 2024-02-01Bibliographically approved
Akbari, S., Root, A., Skrifvars, M., Kumar Ramamoorthy, S. & Åkesson, D. (2023). Novel Bio-based Branched Unsaturated Polyester Resins for High-Temperature Applications. Journal of Polymers and the Environment
Open this publication in new window or tab >>Novel Bio-based Branched Unsaturated Polyester Resins for High-Temperature Applications
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2023 (English)In: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919Article in journal (Refereed) Published
Abstract [en]

Unsaturated polyester resins, one of the most important thermosets, are invariably produced from oil-based monomers. Their application is limited in areas where high thermal stability is required due to their low Tg. Besides, these resins contain 30–40% hazardous styrene as a reactive solvent. Therefore, developing bio-based solventless unsaturated polyester resin with medium to high thermomechanical properties compared to petrochemical-based counterparts is important. In order to achieve this, a series of branched bio-based unsaturated polyester resins were synthesized using bulk polymerization method in two steps. In the first step, four different intermediates were prepared by reacting glycerol (as a core molecule) with either isosorbide (diol), 1,3-propanediol (diol), 2,5-furandicarboxylic acid (saturated diacid), or adipic acid (saturated diacid). In the second step, the branched intermediate was end capped with methacrylic anhydride to introduce reactive sites for cross-linking on the branch ends. The chemical structure of the resins was characterized by 13C-NMR. FT-IR confirmed the polycondensation reaction in the first step and the end functionalization of the resins with methacrylic anhydride in the second step. The effect of 2,5-furandicarboxylic acid and isosorbide on thermomechanical and thermal properties was investigated using dynamic mechanical analysis, differential scanning calorimetry, and thermo-gravimetric analysis. Results indicated that 2,5-furandicarboxylic acid based resins had superior thermomechanical properties compared to a commercial reference unsaturated polyester resin, making them promising resins for high-temperature composite applications. For example, the resin based on 2,5-furandicarboxylic acid and isosorbide and the resin based on 2,5-furandicarboxylic acid and 1,3-propanediol gave glass transition temperatures of 173 °C and 148 °C, respectively. Although the synthesized 2,5-furandicarboxylic acid based resins had higher viscosity (22.7 Pas) than conventional unsaturated polyester (0.4–0.5 Pas) at room temperature, preheated resins can be used for making high-temperature-tolerance fiber-reinforced composite. 

Keywords
Bio-based unsaturated polyester resins, Isosorbide, 2, 5-Furandicarboxylic acid, High-Tg
National Category
Polymer Chemistry
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-30990 (URN)10.1007/s10924-023-03112-5 (DOI)001103740600001 ()2-s2.0-85176301334 (Scopus ID)
Available from: 2023-12-12 Created: 2023-12-12 Last updated: 2024-02-01Bibliographically approved
Kopf, S., Åkesson, D. & Skrifvars, M. (2023). Textile Fiber Production of Biopolymers - A Review of Spinning Techniques for Polyhydroxyalkanoates in Biomedical Applications. Paper presented at Volume 63, 2023. Polymer reviews, 200-245
Open this publication in new window or tab >>Textile Fiber Production of Biopolymers - A Review of Spinning Techniques for Polyhydroxyalkanoates in Biomedical Applications
2023 (English)In: Polymer reviews, ISSN 1558-3724, p. 200-245Article, review/survey (Refereed) Published
Abstract [en]

The superior biocompatibility and biodegradability of polyhydroxyalkanoates (PHAs) compared to man-made biopolymers such as polylactic acid promise huge potential in biomedical applications, especially tissue engineering (TE). Textile fiber-based TE scaffolds offer unique opportunities to imitate the anisotropic, hierarchical, or strain-stiffening properties of native tissues. A combination of PHAs' enhanced biocompatibility and fiber-based TE scaffolds could improve the performance of TE scaffolds. However, the PHAs' complex crystallization behavior and the resulting intricate spinning procedures remain a challenge. This review focuses on discussing the developments in PHA melt and wet spinning, their challenges, process parameters, and fiber characteristics while revealing the lack of an in-depth fiber characterization of wet-spun fibers compared to melt-spun filaments, leading to squandered potential in scaffold development. Additionally, the biomedical application of PHAs other than poly-4-hydroxybutyrate is hampered by a failure of polymer purity to meet the requirements for biomedical applications.

Place, publisher, year, edition, pages
Taylor & Francis, 2023
Keywords
Biopolymers, polyhydroxyalkanoate, fiber, tissue engineering, processing, X-RAY-DIFFRACTION, MECHANICAL-PROPERTIES, POLY(3-HYDROXYBUTYRATE) FIBERS, STERILIZATION TECHNIQUES, ENZYMATIC DEGRADATION, NUCLEATING-AGENTS, POLYMER FIBERS, BORON-NITRIDE, CRYSTALLIZATION, SCAFFOLDS
National Category
Polymer Technologies Polymer Chemistry
Identifiers
urn:nbn:se:hb:diva-27964 (URN)10.1080/15583724.2022.2076693 (DOI)000800499300001 ()2-s2.0-85131173023 (Scopus ID)
Conference
Volume 63, 2023
Available from: 2022-06-07 Created: 2022-06-07 Last updated: 2024-01-16Bibliographically approved
Asadollahzadeh, M., Mahboubi, A., Taherzadeh, M. J., Åkesson, D. & Lennartsson, P. R. (2022). Application of Fungal Biomass for the Development of New Polylactic Acid-Based Biocomposites. Polymers, 14(9)
Open this publication in new window or tab >>Application of Fungal Biomass for the Development of New Polylactic Acid-Based Biocomposites
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2022 (English)In: Polymers, E-ISSN 2073-4360, Vol. 14, no 9Article in journal (Refereed) Published
Abstract [en]

Fungal biomass (FB), a by-product of the fermentation processes produced in large volumes, is a promising biomaterial that can be incorporated into poly(lactic acid) (PLA) to develop enhanced biocomposites that fully comply with the biobased circular economy concept. The PLA/FB composites, with the addition of triethyl citrate (TEC) as a biobased plasticizer, were fabricated by a microcompounder at 150 °C followed by injection molding. The effects of FB (10 and 20 wt %) and TEC (5, 10, and 15 wt %) contents on the mechanical, thermal and surface properties of the biocomposites were analyzed by several techniques. The PLA/FB/TEC composites showed a rough surface in their fracture section. A progressive decrease in tensile strength and Young’s modulus was observed with increasing FB and TEC, while elongation at break and impact strength started to increase. The neat PLA and biocomposite containing 10% FB and 15% TEC exhibited the lowest (3.84%) and highest (224%) elongation at break, respectively. For all blends containing FB, the glass transition, crystallization and melting temperatures were shifted toward lower values compared to the neat PLA. The incorporation of FB to PLA thus offers the possibility to overcome one of the main drawbacks of PLA, which is brittleness.

Keywords
fungal biomass (FB), poly(lactic acid) (PLA), triethyl citrate (TEC), biopolymers, biocomposite, brittleness
National Category
Bio Materials Polymer Chemistry Polymer Technologies
Research subject
Resource Recovery; Resource Recovery
Identifiers
urn:nbn:se:hb:diva-27785 (URN)10.3390/polym14091738 (DOI)000794417800001 ()2-s2.0-85129100044 (Scopus ID)
Available from: 2022-04-26 Created: 2022-04-26 Last updated: 2024-01-17Bibliographically approved
Vu, H. D., Mahboubi, A., Ferreira, J., Taherzadeh, M. J. & Åkesson, D. (2022). Polyhydroxybutyrate-Natural Fiber Reinforcement Biocomposite Production and Their Biological Recyclability through Anaerobic Digestion. Energies, 15(23)
Open this publication in new window or tab >>Polyhydroxybutyrate-Natural Fiber Reinforcement Biocomposite Production and Their Biological Recyclability through Anaerobic Digestion
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2022 (English)In: Energies, E-ISSN 1996-1073, Vol. 15, no 23Article in journal (Refereed) Published
Abstract [en]

The existing recycling methods of PHA-based material are ineffective in terms of increasing resource efficiency and the production of high value end-of-life products. Therefore, in this study, a novel approach of acidogenic fermentation was proposed to recycle PHB-based composites reinforced with natural fibers such as cellulose, chitin, chitosan, orange waste, sawdust, soy protein, and starch. The inclusion of cellulose, chitosan, and sawdust improved the impact properties of the composites while other fillers had various effects on the mechanical properties. These three composites and neat PHB were subsequently subjected to biological degradation via acidogenic digestion to determine the possibility of converting PHB-based composites into volatile fatty acids (VFAs). Two different pH levels of 6 and 10 were applied to assess the effect of pH on the bioconversion and inhibition of the methanogenesis. The results showed promising PHB degradation, contributing to considerable VFA production of 2.5 g/L at pH 6 after 47 days. At pH 6, the presence of the natural fibers in the biocomposites promoted the degradation rate. On the contrary, pH 10 proved to be more suitable for the degradation of the fibers. The VFA which is produced can be recirculated into PHB production, fitting with the concept of a circulating bioeconomy.

Keywords
acidogenic fermentation, biocomposites, biological recycling, natural fillers, polyhydroxybutyrate, volatile fatty acids
National Category
Other Industrial Biotechnology
Research subject
Resource Recovery; Resource Recovery
Identifiers
urn:nbn:se:hb:diva-29180 (URN)10.3390/en15238934 (DOI)000897348900001 ()2-s2.0-85143809706 (Scopus ID)
Available from: 2023-01-03 Created: 2023-01-03 Last updated: 2023-08-28Bibliographically approved
Vu, H. D., Mahboubi, A., Root, A., Heinmaa, I., Taherzadeh, M. J. & Åkesson, D. (2022). Thorough Investigation of the Effects of Cultivation Factors on Polyhydroalkanoates (PHAs) Production by Cupriavidus necator from Food Waste-Derived Volatile Fatty Acids. Fermentation, 8(11), Article ID 605.
Open this publication in new window or tab >>Thorough Investigation of the Effects of Cultivation Factors on Polyhydroalkanoates (PHAs) Production by Cupriavidus necator from Food Waste-Derived Volatile Fatty Acids
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2022 (English)In: Fermentation, E-ISSN 2311-5637, Vol. 8, no 11, article id 605Article in journal (Refereed) Published
Abstract [en]

Volatile fatty acids (VFAs) have become promising candidates for replacing the conventional expensive carbon sources used to produce polyhydroxyalkanoates (PHAs). Considering the inhibitory effect of VFAs at high concentrations and the influence of VFA mixture composition on bacterial growth and PHA production, a thorough investigation of different cultivation parameters such as VFA concentrations and composition (synthetic and waste-derived VFAs) media, pH, aeration, C/N ratio, and type of nitrogen sources was conducted. Besides common VFAs of acetic, butyric and propionic acids, Cupriavidus necator showed good capability for assimilating longer-chained carboxylate compounds of valeric, isovaleric, isobutyric and caproic acids in feasible concentrations of 2.5–5 g/L. A combination of pH control at 7.0, C/N of 6, and aeration of 1 vvm was found to be the optimal condition for the bacterial growth, yielding a maximum PHA accumulation and PHA yield on biomass of 1.5 g/L and 56%, respectively, regardless of the nitrogen sources. The accumulated PHA was found to be poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with the percentage of hydroxybutyrate in the range 91–96%. Any limitation in the cultivation factors was found to enhance the PHA yield, the promotion of which was a consequence of the reduction in biomass production.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
biopolymer, polyhydroalkanoates, volatile fatty acids, food waste, acidogenic fermentation
National Category
Bioprocess Technology
Research subject
Resource Recovery; Resource Recovery; Resource Recovery
Identifiers
urn:nbn:se:hb:diva-28962 (URN)10.3390/fermentation8110605 (DOI)000882197500001 ()2-s2.0-85141746651 (Scopus ID)
Available from: 2022-11-23 Created: 2022-11-23 Last updated: 2023-04-28Bibliographically approved
Åkesson, D., Kuzhanthaivelu, G. & Bohlén, M. (2021). Effect of a Small Amount of Thermoplastic Starch Blend on the Mechanical Recycling of Conventional Plastics. Journal of Polymers and the Environment, 29(3), 985-991
Open this publication in new window or tab >>Effect of a Small Amount of Thermoplastic Starch Blend on the Mechanical Recycling of Conventional Plastics
2021 (English)In: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919, Vol. 29, no 3, p. 985-991Article in journal (Refereed) Published
Abstract [en]

The usage of bioplastics could increase in the future which may cause contamination of the waste streams of conventional plastics. The objective of this study was to investigate if a small amount of biopolymer contaminating conventional polymers would significantly affect mechanical and thermal properties. A starch-based plastic was first compounded by blending plasticised starch with PLA (polylactic acid). This polymer blend was subsequently compounded with HDPE (high density polyethylene), PP (polypropylene) or PET (polyethylene terephthalate) at 0%, 1% and 5% of the biopolymer. The compounds were characterised by tensile tests, Charpy impact tests, DSC (differential scanning calorimetry) and FESEM (field emission scanning electron microscopy). Tests showed that PE and PP were not significantly affected in terms of tensile strength and modulus but the elongation at break showed a strong reduction. PET was, on the other hand, incompatible with the starch-based plastic. Already at 1% contamination, PET had lost most of its impact strength.

Place, publisher, year, edition, pages
Springer, 2021
Keywords
Bioplastics, Contamination, Mechanical recycling
National Category
Materials Engineering Chemical Engineering
Identifiers
urn:nbn:se:hb:diva-24805 (URN)10.1007/s10924-020-01933-2 (DOI)000582309900001 ()2-s2.0-85093704112 (Scopus ID)
Available from: 2021-01-25 Created: 2021-01-25 Last updated: 2023-10-12Bibliographically approved
Vu, H. D., Wainaina, S., Taherzadeh, M. J., Åkesson, D. & Ferreira, J. (2021). Production of polyhydroxyalkanoates (PHAs) by Bacillus megaterium using food waste acidogenic fermentation-derived volatile fatty acids. Bioengineered, 12(1), 2480-2498
Open this publication in new window or tab >>Production of polyhydroxyalkanoates (PHAs) by Bacillus megaterium using food waste acidogenic fermentation-derived volatile fatty acids
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2021 (English)In: Bioengineered, ISSN 2165-5979, E-ISSN 2165-5987, Vol. 12, no 1, p. 2480-2498Article in journal (Refereed) Published
Abstract [en]

High production costs still hamper fast expansion of commercial production of polyhydroxyalkanoates (PHAs). This problem is greatly related to the cultivation medium which accounts for up to 50% of the whole process costs. The aim of this research work was to evaluate the potential of using volatile fatty acids (VFAs), derived from acidogenic fermentation of food waste, as inexpensive carbon sources for the production of PHAs through bacterial cultivation. Bacillus megaterium could assimilate glucose, acetic acid, butyric acid, and caproic acid as single carbon sources in synthetic medium with maximum PHAs production yields of 9–11%, on a cell dry weight basis. Single carbon sources were then replaced by a mixture of synthetic VFAs and by a VFAs-rich stream from the acidogenic fermentation of food waste. After 72 h of cultivation, the VFAs were almost fully consumed by the bacterium in both media and PHAs production yields of 9–10%, on cell dry weight basis, were obtained. The usage of VFAs mixture was found to be beneficial for the bacterial growth that tackled the inhibition of propionic acid, iso-butyric acid, and valeric acid when these volatile fatty acids were used as single carbon sources. The extracted PHAs were revealed to be polyhydroxybutyrate (PHB) by characterization methods of Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The obtained results proved the possibility of using VFAs from acidogenic fermentation of food waste as a cheap substrate to reduce the cost of PHAs production. 

Place, publisher, year, edition, pages
Taylor & Francis Group, 2021
Keywords
Acidogenic fermentation, bacillus megaterium, biopolymers, food waste, polyhydroxyalkanoates, polyhydroxybutyrate, volatile fatty acids
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-25820 (URN)10.1080/21655979.2021.1935524 (DOI)000660944800001 ()34115556 (PubMedID)2-s2.0-85107737778 (Scopus ID)
Available from: 2021-07-06 Created: 2021-07-06 Last updated: 2023-04-28
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7377-0765

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