| 1. |
- Aherne, Olivia, et al.
(författare)
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A novel multiplex fluorescent-labeling method for the visualization of mixed-species biofilms in vitro
- 2024
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Ingår i: Microbiology Spectrum. - : American Society for Microbiology. - 2165-0497. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- In nature, bacteria usually exist as mixed-species biofilms, where they engage in a range of synergistic and antagonistic interactions that increase their resistance to environmental challenges. Biofilms are a major cause of persistent infections, and dispersal from initial foci can cause new infections at distal sites thus warranting further investigation. Studies of development and spatial interactions in mixed-species biofilms can be challenging due to difficulties in identifying the different bacterial species in situ. Here, we apply CellTrace dyes to studies of biofilm bacteria and present a novel application for multiplex labeling, allowing identification of different bacteria in mixed-species, in vitro biofilm models. Oral bacteria labeled with CellTrace dyes (far red, yellow, violet, and CFSE [green]) were used to create single- and mixed-species biofilms, which were analyzed with confocal spinning disk microscopy (CSDM). Biofilm supernatants were studied with flow cytometry (FC). Both Gram-positive and Gram-negative bacteria were well labeled and CSDM revealed biofilms with clear morphology and stable staining for up to 4 days. Analysis of CellTrace labeled cells in supernatants using FC showed differences in the biofilm dispersal between bacterial species. Multiplexing with different colored dyes allowed visualization of spatial relationships between bacteria in mixed-species biofilms and relative coverage by the different species was revealed through segmentation of the CSDM images. This novel application, thus, offers a powerful tool for studying structure and composition of mixed-species biofilms in vitro. IMPORTANCE Although most chronic infections are caused by mixed-species biofilms, much of our knowledge still comes from planktonic cultures of single bacterial species. Studies of formation and development of mixed-species biofilms are, therefore, required. This work describes a method applicable to labeling of bacteria for in vitro studies of biofilm structure and dispersal. Critically, labeled bacteria can be multiplexed for identification of different species in mixed-species biofilms using confocal spinning disk microscopy, facilitating investigation of biofilm development and spatial interactions under different environmental conditions. The study is an important step in increasing the tools available for such complex and challenging studies. IMPORTANCE Although most chronic infections are caused by mixed-species biofilms, much of our knowledge still comes from planktonic cultures of single bacterial species. Studies of formation and development of mixed-species biofilms are, therefore, required. This work describes a method applicable to labeling of bacteria for in vitro studies of biofilm structure and dispersal. Critically, labeled bacteria can be multiplexed for identification of different species in mixed-species biofilms using confocal spinning disk microscopy, facilitating investigation of biofilm development and spatial interactions under different environmental conditions. The study is an important step in increasing the tools available for such complex and challenging studies.
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| 2. |
- Aherne, Olivia, et al.
(författare)
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Effects of stabilized hypochlorous acid on oral biofilm bacteria
- 2022
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Ingår i: BMC Oral Health. - : BioMed Central (BMC). - 1472-6831. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Caries and periodontitis are amongst the most prevalent diseases worldwide, leading to pain and loss of oral function for those affected. Prevention relies heavily on mechanical removal of dental plaque biofilms but for populations where this is not achievable, alternative plaque control methods are required. With concerns over undesirable side-effects and potential bacterial resistance due to the use of chlorhexidine gluconate (CHX), new antimicrobial substances for oral use are greatly needed. Here we have investigated the antimicrobial effect of hypochlorous acid (HOCl), stabilized with acetic acid (HAc), on oral biofilms and compared it to that of CHX. Possible adverse effects of stabilized HOCl on hydroxyapatite surfaces were also examined.METHODS: Single- and mixed-species biofilms of six common oral bacteria (Streptococcus mutans, Streptococcus gordonii, Actinomyces odontolyticus, Veillonella parvula, Parvimonas micra and Porphyromonas gingivalis) within a flow-cell model were exposed to HOCl stabilized with 0.14% or 2% HAc, pH 4.6, as well as HOCl or HAc alone. Biofilm viability was assessed in situ using confocal laser scanning microscopy following LIVE/DEAD® BacLight™ staining. In-situ quartz crystal microbalance with dissipation (QCM-D) was used to study erosion of hydroxyapatite (HA) surfaces by stabilized HOCl.RESULTS: Low concentrations of HOCl (5 ppm), stabilized with 0.14% or 2% HAc, significantly reduced viability in multi-species biofilms representing supra- and sub-gingival oral communities, after 5 min, without causing erosion of HA surfaces. No equivalent antimicrobial effect was seen for CHX. Gram-positive and Gram-negative bacteria showed no significant differential suceptibility to stabilized HOCl.CONCLUSIONS: At low concentrations and with exposure times which could be achieved through oral rinsing, HOCl stabilized with HAc had a robust antimicrobial activity on oral biofilms, without causing erosion of HA surfaces or affecting viability of oral keratinocytes. This substance thus appears to offer potential for prevention and/or treatment of oral biofilm-mediated diseases.
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| 3. |
- Aidoukovitch, Alexandra, et al.
(författare)
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Exogenous LL-37 but not homogenates of desquamated oral epithelial cells shows activity against Streptococcus mutans
- 2021
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Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 79:6, s. 466-472
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The antimicrobial peptide hCAP18/LL-37 is detected in desquamated epithelial cells of human whole saliva, but the functional importance of this pool of hCAP18/LL-37 is not understood. Here, we assess the impact of homogenates of desquamated oral epithelial cells and exogenous, synthetic LL-37 on two oral bacteria: S. mutans and S. gordonii. Material and methods: Desquamated epithelial cells of unstimulated whole saliva were isolated and cellular and extracellular levels of hCAP18/LL-37 analyzed by ELISA. Bacterial viability was determined by BacLight Live/Dead staining and confocal laser scanning microscopy. Results: Desquamated oral epithelial cells harboured hCAP18/LL-37, and they spontaneously released/leaked the peptide to their medium. Exogenous, synthetic LL-37 showed cytotoxic activity against S. mutans but not S gordonii, suggesting that LL-37 acts differentially on these two types of oral bacteria. Homogenates of desquamated oral epithelial cells had no effect on S. mutans viability. Treatment with exogenous, synthetic LL-37 (8 and 10 μM) reduced S. mutans viability, whereas lower concentrations (0.1 and 1 µM) of the peptide lacked effect. Conclusions: Desquamated oral epithelial cells contain hCAP18/LL-37, but their cellular levels of hCAP18/LL-37 are too low to affect S. mutans viability, whereas exogenous, synthetic LL-37 has a strong effect on these bacteria.
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| 4. |
- Bertl, Kristina, et al.
(författare)
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Bacterial colonization of a power-driven water flosser during regular use : A proof-of-principle study
- 2021
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Ingår i: Clinical and Experimental Dental Research. - : John Wiley & Sons. - 2057-4347. ; 7:5, s. 656-663
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The present proof-of-principle study assessed whether daily use of a power-driven water flosser (Sonicare AirFloss; SAF) leads to bacterial colonization in the nozzle and/or the device, resulting in contaminated water-jet.MATERIAL AND METHODS: In five participants, saliva samples at baseline and water-jet samples of devices used daily with bottled water for 3 weeks (test) were collected. Additionally, water-jet samples from devices used daily with bottled water extra-orally for 3 weeks (positive control) and from brand new devices (negative control), as well as samples from newly opened and 1- and 3-week opened water bottles were collected. Colony forming units (CFU) were recorded after 48 h culturing and 20 oral pathogens were assessed by polymerase chain reaction-based analysis.RESULTS: Distinct inter-individual differences regarding the number of detected bacteria were observed; water-jet samples of test devices included both aerobic and anaerobic bacterial species, with some similarities to the saliva sample of the user. Water-jet samples from positive control devices showed limited number of aerobic and anaerobic bacterial species, while the samples from negative control devices did not show any bacterial species. Very few aerobic bacteria were detected only in the 3-week-old bottled water samples, while samples of newly and 1-week opened water bottles did not show any bacterial growth.CONCLUSIONS: The present proof-of-principle study showed that daily use of a power-driven water flosser for 3 weeks resulted in bacterial colonization in the nozzle and/or device with both aerobic and anaerobic, not only oral, species, that are transmitted via the water-jet.
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| 5. |
- Boisen, Gabriella, et al.
(författare)
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Acid tolerance in early colonizers of oral biofilms
- 2021
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Ingår i: BMC Microbiology. - : BioMed Central. - 1471-2180. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In caries, low pH drives selection and enrichment of acidogenic and aciduric bacteria in oral biofilms, and development of acid tolerance in early colonizers is thought to play a key role in this shift. Since previous studies have focussed on planktonic cells, the effect of biofilm growth as well as the role of a salivary pellicle on this process is largely unknown. We explored acid tolerance and acid tolerance response (ATR) induction in biofilm cells of both clinical and laboratory strains of three oral streptococcal species (Streptococcus gordonii, Streptococcus oralis and Streptococcus mutans) as well as two oral species of Actinomyces (A. naeslundii and A. odontolyticus) and examined the role of salivary proteins in acid tolerance development.METHODS: Biofilms were formed on surfaces in Ibidi® mini flow cells with or without a coating of salivary proteins and acid tolerance assessed by exposing them to a challenge known to kill non-acid tolerant cells (pH 3.5 for 30 min) followed by staining with LIVE/DEAD BacLight and confocal scanning laser microscopy. The ability to induce an ATR was assessed by exposing the biofilms to an adaptation pH (pH 5.5) for 2 hours prior to the low pH challenge.RESULTS: Biofilm formation significantly increased acid tolerance in all the clinical streptococcal strains (P < 0.05) whereas the laboratory strains varied in their response. In biofilms, S. oralis was much more acid tolerant than S. gordonii or S. mutans. A. naeslundii showed a significant increase in acid tolerance in biofilms compared to planktonic cells (P < 0.001) which was not seen for A. odontolyticus. All strains except S. oralis induced an ATR after pre-exposure to pH 5.5 (P < 0.05). The presence of a salivary pellicle enhanced both acid tolerance development and ATR induction in S. gordonii biofilms (P < 0.05) but did not affect the other bacteria to the same extent.CONCLUSIONS: These findings suggest that factors such as surface contact, the presence of a salivary pellicle and sensing of environmental pH can contribute to the development of high levels of acid tolerance amongst early colonizers in oral biofilms which may be important in the initiation of caries.
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| 6. |
- Boisen, Gabriella, et al.
(författare)
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Limosilactobacillus reuteri inhibits the acid tolerance response in oral bacteria
- 2023
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Ingår i: Biofilm. - : Elsevier. - 2590-2075. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Probiotic bacteria show promising results in prevention of the biofilm-mediated disease caries, but the mechanisms are not fully understood. The acid tolerance response (ATR) allows biofilm bacteria to survive and metabolize at low pH resulting from microbial carbohydrate fermentation. We have studied the effect of probiotic strains: Limosilactobacillus reuteri and Lacticaseibacillus rhamnosus on ATR induction in common oral bacteria. Communities of L. reuteri ATCC PTA5289 and Streptoccus gordonii, Streptococcus oralis, Streptococcus mutans or Actinomyces naeslundii in the initial stages of biofilm formation were exposed to pH 5.5 to allow ATR induction, followed by a low pH challenge. Acid tolerance was evaluated as viable cells after staining with LIVE/ DEAD & REG;BacLightTM. The presence of L. reuteri ATCC PTA5289 caused a significant reduction in acid tolerance in all strains except S. oralis. When S. mutans was used as a model organism to study the effects of additional probiotic strains (L. reuteri SD2112, L. reuteri DSM17938 or L. rhamnosus GG) as well as L. reuteri ATCC PTA5289 supernatant on ATR development, neither the other probiotic strains nor supernatants showed any effect. The presence of L. reuteri ATCC PTA5289 during ATR induction led to down-regulation of three key genes involved in tolerance of acid stress (luxS, brpA and ldh) in Streptococci. These data suggest that live cells of probiotic L. reuteri ATCC PTA5289 can interfere with ATR development in common oral bacteria and specific strains of L. reuteri may thus have a role in caries prevention by inhibiting development of an acid-tolerant biofilm microbiota.
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| 7. |
- Davies, Julia R, 1962-, et al.
(författare)
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ARTICULATE : A European glossary of terms used in oral health professional education
- 2023
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Ingår i: European journal of dental education. - : John Wiley & Sons. - 1396-5883 .- 1600-0579. ; 27:2, s. 209-222
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The Erasmus+O-Health-EDU project aims to gain a comprehensive view of oral health professional (OHP) education in Europe, through the development of web-based surveys and online toolkits. A glossary to facilitate a common language through which academic teams could cooperate and communicate more accurately was identified as a key need within the project. The aim of ARTICULATE was thus to create a shared language, with a European focus, for terms and concepts used in the field of OHP education.METHODS: The methodology was developed from those published for construction of other glossaries with a circular and iterative process: the creation of content and definitions by a group of experts in OHP education, the testing of "fitness for purpose" of the content, and stakeholder consultation. All creation steps were followed by refinements based on testing results and stakeholder comments. The final glossary was then launched as an online resource including a built-in mechanism for user feedback.RESULTS: The scope and structure of the glossary were mapped out at a workshop with 12 dental education experts from 7 European countries. A total of 328 terms were identified, of which 171 were finally included in ARTICULATE. After piloting with a close group of other colleagues, the glossary was opened for external input. Thirty European Deans or Heads of Education assessed the definition of each term as "clear" or "not clear." A total of 86 definitions were described as "clear" by all individuals. Terms deemed unclear by at least one individual were revisited and changes made to 37 of the definitions. In conjunction with the launch of the glossary, a range of stakeholder organisations were informed and asked to participate in an open global consultation by providing feedback online. Since its launch in June 2021, the ARTICULATE website (https://o-health-edu.org/articulate) has had an average of 500 visits/month. To promote community ownership, forms embedded on the ARTICULATE webpage allow users to give feedback and suggest new terms. A standing taskforce will meet regularly to consider amendments and make changes to ensure that the glossary remains a relevant and up-to-date resource over time.CONCLUSION: ARTICULATE is a unique, evolving, online glossary of terms relating to OHP education, created as a resource for all interested OHP educators. The glossary is a key output of the O-Health-Edu project, which relies on a comprehensive vision of OHP education to address the future oral health needs of the European population.
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| 8. |
- Davies, Julia R, 1962-, et al.
(författare)
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Polymicrobial synergy stimulates Porphyromonas gingivalis survival and gingipain expression in a multi-species subgingival community
- 2021
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Ingår i: BMC Oral Health. - : BioMed Central. - 1472-6831. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dysbiosis in subgingival microbial communities, resulting from increased inflammatory transudate from the gingival tissues, is an important factor in initiation and development of periodontitis. Dysbiotic communities are characterized by increased numbers of bacteria that exploit the serum-like transudate for nutrients, giving rise to a proteolytic community phenotype. Here we investigate the contribution of interactions between members of a sub-gingival community to survival and development of virulence in a serum environment-modelling that in the subgingival pocket.METHODS: Growth and proteolytic activity of three Porphyromonas gingivalis strains in nutrient broth or a serum environment were assessed using A600 and a fluorescent protease substrate, respectively. Adherence of P. gingivalis strains to serum-coated surfaces was studied with confocal microscopy and 2D-gel electrophoresis of bacterial supernatants used to investigate extracellular proteins. A model multi-species sub-gingival community containing Fusobacterium nucleatum, Streptococcus constellatus, Parvimonas micra with wild type or isogenic mutants of P. gingivalis was then created and growth and proteolytic activity in serum assessed as above. Community composition over time was monitored using culture techniques and qPCR.RESULTS: The P. gingivalis strains showed different growth rates in nutrient broth related to the level of proteolytic activity (largely gingipains) in the cultures. Despite being able to adhere to serum-coated surfaces, none of the strains was able to grow alone in a serum environment. Together in the subgingival consortium however, all the included species were able to grow in the serum environment and the community adopted a proteolytic phenotype. Inclusion of P. gingivalis strains lacking gingipains in the consortium revealed that community growth was facilitated by Rgp gingipain from P. gingivalis.CONCLUSIONS: In the multi-species consortium, growth was facilitated by the wild-type and Rgp-expressing strains of P. gingivalis, suggesting that Rgp is involved in delivery of nutrients to the whole community through degradation of complex protein substrates in serum. Whereas they are constitutively expressed by P. gingivalis in nutrient broth, gingipain expression in the model periodontal pocket environment (serum) appeared to be orchestrated through signaling to P. gingivalis from other members of the community, a phenomenon which then promoted growth of the whole community.
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| 9. |
- Dixon, Jonathan, et al.
(författare)
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O-HEALTH-EDU : A scoping review on the reporting of oral health professional education in Europe.
- 2021
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Ingår i: European journal of dental education. - : John Wiley & Sons. - 1396-5883 .- 1600-0579. ; 25:1, s. 56-77
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The variability in oral health professional education is likely to impact on the management of oral health needs across Europe. This scoping review forms the initial part of a larger EU-funded collaborative Erasmus + project, 'O-Health-Edu'. The aim of this scoping review is to investigate how oral health professional education in Europe is reported.METHODS: The PRISMA and Arksey & O'Malley methodological frameworks for scoping reviews were used to guide reviewers in answering the research question "How is oral health professional education reported in Europe?". The search strategy encompassed published literature searches, internet searches and further searching of relevant documents from educational organisations, regulators and professional bodies. Once the search strategy was developed, it was sent to key stakeholders for consultation. Sources were reviewed by two authors (JD, JF) and included in the review if they reported on oral health professional education in Europe.RESULTS: A total of 508 sources were retrieved from all of the searches. A total of 405 sources were excluded as they did not report on the topic of interest, leaving 103 sources that reported on oral health professional education in Europe. Handsearching the references of published sources lead to a further 41 sources being screened, of which, 15 were included. In total, 33 duplications were removed and the final number of included sources was 85. The average year of publication for the included sources was 2007, with sources most commonly published in journals dedicated to dental education. Surveys represented the most common form of reporting. From the data obtained, four broad themes of reporting were evident: dental education at a programme level, dental education at a discipline level, other oral health professional education, and postgraduate education and continuous professional development.CONCLUSION: The reporting of dental and oral health professional education in Europe is limited. Whilst there are many useful documents that provide guidelines on dental education, there is limited knowledge on how education is implemented and delivered. There is a greater need for comprehensive educationally driven programme-level data on oral health professional education across Europe.
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| 10. |
- Dixon, Jonathan, et al.
(författare)
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O-HEALTH-EDU : A viewpoint into the current state of Oral Health Professional education in Europe: Part 1: Programme-level data
- 2024
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Ingår i: European journal of dental education. - : John Wiley & Sons. - 1396-5883 .- 1600-0579. ; 28:2, s. 591-606
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Current legislation leaves Oral Health Professional (OHP) education open to wide interpretation and may result in significant variation in educational practice and resultant professional attributes across Europe. Data regarding the current state of OHP education across Europe is limited. The aim of Part 1 of this series is to provide programme-level data for Primary Dental Degree Programmes, Dental Hygiene and Postgraduate Education.Methods: A 91-item questionnaire was developed following the Delphi method. The questionnaire and the Articulate glossary of OHP education terms were developed concurrently to facilitate a common understanding of language. Piloting was performed in multiple stages and included institutions internal and external to the research group. The questionnaire was uploaded online and converted to a data hub, allowing dental schools to control their own data and update the data provided whenever they wish. All ADEE member schools (n = 144) were invited to provide data. Forty questions relating to school details, Primary Dental Degree Programmes, Dental Hygiene and Postgraduate Education were included in this part of the series.Results: Seventy-one institutions from 25 European countries provided data between June 2021 and April 2023, which represents a response rate of 49.3% of ADEE members. Programme-level data for Primary Dental Degree Programmes, Dental Hygiene and Postgraduate Education is presented including programme length, funding, languages and fees, student numbers and demographics, student admission and selection processes and permission to practice after graduation.Conclusion: This series of papers, as far as the authors are aware, are the first attempts to build a comprehensive picture of the current state of OHP education in Europe. A comprehensive view of the state of OHP education in Europe is not yet available but the O-Health-Edu data hub provides a means for all education providers in Europe to contribute data to reach this goal. It is anticipated that the data hub will be updated and built upon over time to continually establish a clearer picture of the state of OHP education in Europe.
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