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Yazdani A, Halvaei I, Boniface C, Esfandiari N. Effect of cytoplasmic fragmentation on embryo development, quality, and pregnancy outcome: a systematic review of the literature. Reprod Biol Endocrinol 2024; 22:55. [PMID: 38745305 PMCID: PMC11092204 DOI: 10.1186/s12958-024-01217-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 04/01/2024] [Indexed: 05/16/2024] Open
Abstract
The role of cytoplasmic fragmentation in human embryo development and reproductive potential is widely recognized, albeit without standard definition nor agreed upon implication. While fragmentation is best understood to be a natural process across species, the origin of fragmentation remains incompletely understood and likely multifactorial. Several factors including embryo culture condition, gamete quality, aneuploidy, and abnormal cytokinesis seem to have important role in the etiology of cytoplasmic fragmentation. Fragmentation reduces the volume of cytoplasm and depletes embryo of essential organelles and regulatory proteins, compromising the developmental potential of the embryo. While it has been shown that degree of fragmentation and embryo implantation potential are inversely proportional, the degree, pattern, and distribution of fragmentation as it relates to pregnancy outcome is debated in the literature. This review highlights some of the challenges in analysis of fragmentation, while revealing trends in our evolving knowledge of how fragmentation may relate to functional development of the human embryos, implantation, and pregnancy outcome.
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Affiliation(s)
- Ariella Yazdani
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Medical Center, The Robert Larner College of Medicine at the University of Vermont, Burlington, VT, 05405, USA
- Present address: Obstetrics and Gynecology Institute, Cleveland Clinic Foundation, Cleveland, OH, 44195, USA
| | - Iman Halvaei
- Department of Anatomical Sciences, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Catherine Boniface
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Medical Center, The Robert Larner College of Medicine at the University of Vermont, Burlington, VT, 05405, USA
| | - Navid Esfandiari
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Medical Center, The Robert Larner College of Medicine at the University of Vermont, Burlington, VT, 05405, USA.
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology and Reproductive Sciences, University of Vermont, 111 Colchester Avenue, Burlington, Vermont, 05401, USA.
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Shioya M, Okabe-Kinoshita M, Kobayashi T, Fujita M, Takahashi K. Human metaphase II oocytes with narrow perivitelline space have poor fertilization, developmental, and pregnancy potentials. J Assist Reprod Genet 2024; 41:1449-1458. [PMID: 38499932 PMCID: PMC11143139 DOI: 10.1007/s10815-024-03084-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/04/2024] [Indexed: 03/20/2024] Open
Abstract
PURPOSE To analyze the fertilization, developmental, and pregnancy potentials in oocytes with narrow perivitelline space. METHODS Perivitelline space (PVS) of oocytes was evaluated at the time of ICSI, and those without sufficient PVS were judged as oocytes with narrow PVS (NPVS oocytes), and those with sufficient PVS formation were judged as oocytes with non-narrow PVS (non-NPVS oocytes). The analysis included 634 NPVS oocytes from 278 cycles and 12,121 non-NPVS oocytes from 1698 cycles. The fertilization and developmental potentials of NPVS and non-NPVS oocytes were compared by calculating odds ratios using a mixed-effects logistic regression model. We also compared the embryo transfer outcomes of those used for single vitrified-warmed blastocyst transfer after developing into the blastocyst stage. RESULTS NPVS oocytes had higher odds ratios for degeneration (adjusted odds ratio [aOR], 1.555; 95% confidence interval [CI], 1.096-2.206; p = 0.0133) and 0PN (aOR, 1.387; 95% CI, 1.083-1.775; p = 0.0095), resulting in a lower 2PN rate (aOR, 0.761; 95% CI, 0.623-0.929; p = 0.0072). Even embryos with confirmed 2PN had lower odds ratios for cleavage (aOR, 0.501; 95% CI, 0.294-0.853; p = 0.0109) and blastocyst development (Gardner criteria; CC-AA) rates (aOR, 0.612; 95% CI, 0.476-0.788; p = 0.0001). Blastocysts developed from NPVS oocytes had significantly lower odds ratios for clinical pregnancy (aOR, 0.435; 95% CI, 0.222-0.854; p = 0.0156) than those developed from non-NPVS oocytes. CONCLUSIONS Oocytes with NPVS have low fertilization and developmental potential, as well as low likelihood of pregnancy.
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Affiliation(s)
- Masashi Shioya
- Takahashi Women's Clinic, 18-14-6F Shinmachi, Chuo-ku, Chiba, 260-0028, Japan.
- Department of Reproductive Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
| | | | - Tatsuya Kobayashi
- Department of Reproductive Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
- Department of Regulatory Science, Fujita Health University, Haneda Innovation City Zone A, 1-1-4 Haneda Airport, Ota-ku, Tokyo, 144-0041, Japan
| | - Maki Fujita
- Takahashi Women's Clinic, 18-14-6F Shinmachi, Chuo-ku, Chiba, 260-0028, Japan
| | - Keiichi Takahashi
- Takahashi Women's Clinic, 18-14-6F Shinmachi, Chuo-ku, Chiba, 260-0028, Japan
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Ezoe K, Takahashi T, Miki T, Kato K. Developmental perturbation in human embryos: Clinical and biological significance learned from time-lapse images. Reprod Med Biol 2024; 23:e12593. [PMID: 38983691 PMCID: PMC11232294 DOI: 10.1002/rmb2.12593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/30/2024] [Accepted: 06/07/2024] [Indexed: 07/11/2024] Open
Abstract
Background Time-lapse technology (TLT) has gained widespread adoption worldwide. In addition to facilitating the undisturbed culture of embryos, TLT offers the unique capability of continuously monitoring embryos to detect spatiotemporal changes. Although these observed phenomena play a role in optimal embryo selection/deselection, the clinical advantages of introducing TLT remain unclear. However, manual annotation of embryo perturbation could facilitate a comprehensive assessment of developmental competence. This process requires a thorough understanding of embryo observation and the biological significance associated with developmental dogma and variation. This review elucidates the typical behavior and variation of each phenomenon, exploring their clinical significance and research perspectives. Methods The MEDLINE database was searched using PubMed for peer-reviewed English-language original articles concerning human embryo development. Main findings TLT allows the observation of consecutive changes in embryo morphology, serving as potential biomarkers for embryo assessment. In assisted reproductive technology laboratories, several phenomena have not revealed their mechanism, posing difficulties such as fertilization deficiency and morula arrest. Conclusion A profound understanding of the biological mechanisms and significance of each phenomenon is crucial. Further collaborative efforts between the clinical and molecular fields following translational studies are required to advance embryonic outcomes and assessment.
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Fadon P, Gallegos E, Jalota S, Muriel L, Diaz-Garcia C. Time-Lapse Systems: A Comprehensive Analysis on Effectiveness. Semin Reprod Med 2022; 39:e12-e18. [PMID: 35008119 DOI: 10.1055/s-0041-1742149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Time-lapse systems have quickly become a common feature of in vitro fertilization laboratories all over the world. Since being introduced over a decade ago, the alleged benefits of time-lapse technology have continued to grow, from undisturbed culture conditions and round the clock, noninvasive observations to more recent computer-assisted selection of embryos through the development of algorithms. Despite the global uptake of time-lapse technology, its real impact on clinical outcomes is still controversial. This review aims to explore the different features offered by time-lapse technology, discussing incubation, algorithms, artificial intelligence and the regulation of nonessential treatment interventions, while assessing evidence on whether any benefit is offered over conventional technology.
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Affiliation(s)
| | | | | | | | - Cesar Diaz-Garcia
- IVI London, IVIRMA Global, London, United Kingdom.,EGA Institute for Women's Health, University College London, London, United Kingdom
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Shebl O, Trautner PS, Enengl S, Reiter E, Allerstorfer C, Rechberger T, Oppelt P, Ebner T. Ionophore application for artificial oocyte activation and its potential effect on morphokinetics: a sibling oocyte study. J Assist Reprod Genet 2021; 38:3125-3133. [PMID: 34642877 PMCID: PMC8666403 DOI: 10.1007/s10815-021-02338-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/01/2021] [Indexed: 12/19/2022] Open
Abstract
PURPOSE To evaluate whether ionophore application at the oocyte stage changes the morphokinetics of the associated embryos in cases of artificial oocyte activation. METHODS In a prospective sibling oocyte approach, 78 ICSI patients with suspected fertilization problems had half of their MII-oocytes treated with a ready-to-use ionophore (calcimycin) immediately following ICSI (study group). Untreated ICSI eggs served as the control group. Primary analyses focused on morphokinetic behavior and the presence of irregular cleavages. The rates of fertilization, utilization, pregnancy, and live birth rate were also evaluated. RESULTS Ionophore-treated oocytes showed a significantly earlier formation of pronuclei (t2PNa) and a better synchronized third cell cycle (s3) (P < .05). The rate of irregular cleavage was unaffected (P > .05). Ionophore treatment significantly improved the overall rates of fertilization (P < .01) and blastocyst utilization (P < .05). CONCLUSION Ionophore application does not negatively affect cleavage timing nor is it associated with irregular cleavage.
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Affiliation(s)
- Omar Shebl
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Philip Sebastian Trautner
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Sabine Enengl
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Elisabeth Reiter
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Christina Allerstorfer
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Tamara Rechberger
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Peter Oppelt
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria
| | - Thomas Ebner
- Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Kepler University Hospital, MedCampus IV, Krankenhausstr. 26-30, A-4020, Linz, Upper Austria, Austria.
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Coticchio G, Ezoe K, Lagalla C, Shimazaki K, Ohata K, Ninomiya M, Wakabayashi N, Okimura T, Uchiyama K, Kato K, Borini A. Perturbations of morphogenesis at the compaction stage affect blastocyst implantation and live birth rates. Hum Reprod 2021; 36:918-928. [PMID: 33575789 DOI: 10.1093/humrep/deab011] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/17/2020] [Indexed: 12/19/2022] Open
Abstract
STUDY QUESTION Do perturbations of embryo morphogenesis at compaction affect blastocyst development and clinical outcomes in assisted reproduction cycles? SUMMARY ANSWER Cell exclusion and extrusion, i.e. cell disposal occurring respectively before or during morula compaction, affect blastocyst yield and quality, as well as rates of pregnancy and live birth. WHAT IS KNOWN ALREADY Despite its pivotal role in morphogenesis for blastocyst organisation and cell fate determination, compaction at the morula stage has received little attention in clinical embryology. Time lapse technology (TLT) allows detailed morphokinetic analysis of this developmental stage. However, even in the vast majority of previous TLT studies, compaction was investigated without a specific focus. Recently, we reported that compaction may be affected by two clearly-distinct patterns of cell disposal, exclusion and extrusion, occurring prior to and during compaction, respectively. However, the crucial question of the specific relevance of partial compaction for embryo development and competence in ART has remained unanswered until now. STUDY DESIGN, SIZE, DURATION This study involved the assessment of laboratory and clinical outcomes of 2,059 morula stage embryos associated with 1,117 ICSI patients, who were treated with minimal stimulation and single vitrified-warmed blastocyst transfer (SVBT) from April 2017 to March 2018. Patterns of morula compaction were assessed and analyzed in relation to embryonic and clinical outcomes. PARTICIPANTS/MATERIALS, SETTING, METHODS Following ICSI, time-lapse videos were analysed to annotate morphokinetic parameters relevant to both pre- and post-compaction stages. According to their morphokinetic history, morulae were classified as: (I) fully compacted morulae (FCM); (II) partially compacted morulae (PCM), showing cells (a) excluded from the compaction process from the outset (Exc-PCM), (b) extruded from an already compacted morula (Ext-PCM), or (c) showing non-compacted cells arisen from both patterns (Exc/Ext-PCM). The number of excluded/extruded cells was also annotated. Possible correlations of compaction patterns with 13 morphokinetic parameters, abnormal cleavage, blastocyst yield and morphological grade, clinical and ongoing pregnancy rates, and live birth rate were evaluated. Other factors, such as patient and cycle characteristics, possibly associated with compaction patterns and their outcomes, were investigated. MAIN RESULTS AND THE ROLE OF CHANCE Full compaction was observed in 39.0% of all embryos. However, partially compacted morulae (PCM) showing excluded (Exc-PCM), extruded (Ext-PCM) cells, or indeed both phenotypes (Exc/Ext-PCM) were frequently detected (24.8%, 16.6%, and 19.6%, respectively) and collectively (61%) exceeded fully compacted morulae. Blastomere exclusion or extrusion affected one or several cells, in different proportions. In comparison to FCM, the developmental pace of the three PCM groups, observed at 13 developmental stages starting from pronuclear fading, was progressively slower (P < 0.0001). Developmental delay at post-compaction stages was more pronounced in the group showing both patterns of partial compaction. Blastomere exclusion and/or extrusion had a large negative impact on blastocyst development. In particular, rates of blastocyst formation and cryopreservation were very low in the Ext-PCM and Exc/Ext-PCM groups (P < 0.0001). Rates of blastocysts with ICM or TE of highest quality (Grade A) were severely affected in all PCM groups (P < 0.0001). In 1,083 SVBTs, blastocysts derived from all PCM groups produced much lower clinical pregnancy, ongoing pregnancy, and live birth rates (P < 0.0001). All three patterns of partial compaction emerged as factors independently associated with live birth rate, even after multivariate logistic regression analysis including maternal/paternal age, female BMI, and number of previous embryo transfers as possible confounding factors. LIMITATIONS, REASONS FOR CAUTION The retrospective design of the study represents a general limitation. WIDER IMPLICATIONS OF THE FINDINGS This large-scale study represents a further important demonstration of embryo plasticity and above all indicates new robust morphokinetic parameters for improved algorithms of embryo selection. STUDY FUNDING/COMPETING INTEREST(S) This study was exclusively supported by the participating institutions. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER NA.
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Removing the zona pellucida can decrease cytoplasmic fragmentations in human embryos: a pilot study using 3PN embryos and time-lapse cinematography. J Assist Reprod Genet 2020; 37:1349-1354. [PMID: 32285294 PMCID: PMC7311590 DOI: 10.1007/s10815-020-01773-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/01/2020] [Indexed: 10/24/2022] Open
Abstract
PURPOSE The aim of this study was to establish a new method of decreasing cytoplasmic fragmentation in early-stage human embryos. METHODS The zona pellucida (ZP) of abnormally-fertilized oocytes (zygotes with three pronuclei (3PN)), which were donated by patients, was removed at the pronuclear stage. ZP-free embryos were observed in a time-lapse imaging and culturing system in order to examine developmental morphology and embryonic quality. RESULTS Based on a modification of Veeck's criteria, 47 of 69 ZP-free 3PN embryos (68.1%) showed fragmentation of less than 20% of the total volume of cytoplasm at the first cleavage (grades 1 and 2), 17 (24.6%) showed 20-40% cytoplasmic fragments (grade 3), and only 5 (7.2%) showed more than 40% fragments (grade 4). These results suggest that the rate of fragmentation is decreased by ZP removal before the first cleavage, compared with normal (ZP-intact) 3PN and 2-pronuclear/2-polar body embryos. CONCLUSIONS This study revealed that the ZP is not always necessary for normal development after the pronuclear stage because the ZP-free embryos studied herein developed normally, maintained their cell adhesion well, and showed a decreased rate of fragmentation. This innovative culture system might provide the major breakthrough needed for patients who have difficulty obtaining good-quality embryos.
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Ebner T, Sesli Ö, Kresic S, Enengl S, Stoiber B, Reiter E, Oppelt P, Mayer RB, Shebl O. Time-lapse imaging of cytoplasmic strings at the blastocyst stage suggests their association with spontaneous blastocoel collapse. Reprod Biomed Online 2019; 40:191-199. [PMID: 31983545 DOI: 10.1016/j.rbmo.2019.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 01/01/2023]
Abstract
RESEARCH QUESTION To study the origin and temporal behaviour of cytoplasmic strings spanning the blastocoel (main objective) and their influence on treatment outcome (secondary objective). DESIGN This retrospective analysis of prospectively collected data was set up in a university medical centre. Patients who either underwent fresh (n = 95) or vitrified-warmed (n = 55) single blastocyst transfer were included. Time-lapse sequences of in-vitro developed blastocysts were screened for the presence of cytoplasmic strings. Pregnancies in string-positive and string-negative transfers were followed up to live birth. RESULTS A total of 387 blastocysts were obtained in the fresh cycles of 100 patients, corresponding to a blastocyst formation rate of 62.4%. Cytoplasmic strings were first detected around full stage (108.5 ± 6.4 h) in 170 blastocysts (43.9%). The number of strings varied (range: 1-7) and the duration of visibility was 5.2 ± 3.5 h. The occurrence of cytoplasmic strings was significantly associated with the presence of blastocoelic collapses (P < 0.001) but not with any of the annotated morphokinetic parameters. Live birth and neonatal outcome were the same for both string-positive and string-negative pregnancies. Moreover, collapses did not affect treatment outcome. CONCLUSION Time-lapse analysis of cytoplasmic strings at the blastocyst stage revealed that this morphological feature was not a negative predictor as previously reported. Although physiologically normal, at least some of the cytoplasmic strings are an artefact, possibly associated with blastocoelic collapses.
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Affiliation(s)
- Thomas Ebner
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria.
| | - Özcan Sesli
- University for Life, Beethovenstrasse 9, Graz Styria, Austria
| | - Sanja Kresic
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
| | - Sabine Enengl
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
| | - Barbara Stoiber
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
| | - Elisabeth Reiter
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
| | - Peter Oppelt
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
| | - Richard Bernhard Mayer
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
| | - Omar Shebl
- Kepler University, Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Krankenhausstrasse 26-30, Linz Upper Austria, Austria
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Van Blerkom J, Alikani M. Perivitelline threads: an overlooked feature of cleavage-stage human embryos or an epiphenomenon in search of a function? Reprod Biomed Online 2017; 35:625-626. [PMID: 29198321 DOI: 10.1016/j.rbmo.2017.10.105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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