Skeletonema sp. to Phaeocystis sp. The results revealed that bacterial community structure and function shifted with bloom succession. The dominant group in the Skeletonema bloom was Alphaproteobacteria, while Bacteroidia and Gammaproteobacteria dominated the Phaeocystis bloom. The most noticeable feature during the successions was the change from Rhodobacteraceae to Flavobacteriaceae in the bacterial communities. The Shannon diversity indices were significantly higher in the transitional phase of the two blooms. Metabolic reconstruction of the metagenome-assembled genomes (MAGs) showed that dominant bacteria exhibited some environmental adaptability in both blooms, capable of metabolizing the main organic compounds, and possibly providing inorganic sulfur to the host algae. Moreover, we identified specific metabolic capabilities of cofactor biosynthesis  in MAGs in the two algal blooms. In the Skeletonema bloom, Rhodobacteraceae family members might participate in synthesizing vitamin B1 and B12 to the host, whereas in the Phaeocystis bloom, Flavobacteriaceae was the potential contributor for synthesizing vitamin B7 to the host. In addition, signal communication (quorum sensing and indole-3-acetic acid molecules) might have also participated in the bacterial response to bloom succession. Bloom-associated microorganisms showed a noticeable response in composition and function to algal succession. The changes in bacterial community structure and function might be an internal driving factor for the bloom succession.Elucidating the interactions between algal and microbial communities is essential for understanding the dynamic mechanisms regulating algal blooms in the marine environment. Shifts in bacterial communities when a single species dominates algal blooms have been extensively investigated. However, bacterioplankton community dynamics during bloom succession when one algal species shift to another is still poorly understood. In this study, we used metagenomic analysis to investigate the bacterial community composition and function during algal bloom succession from  HoweverSimilar to the plant rhizosphere, the phycosphere environment is important for algae-bacteria interactions . In thisNoctiluca scintillans, making it a mixed-species ecosystem in bloom area  to Phaeocystis  (Skeletonema sp. to Phaeocystis sp.) is frequent and provides an opportunity to study the characteristics of microorganisms associated to algal bloom succession events  , 2011. Tglobosa) . Howevern events . TherefoCommunity-level gene analysis has provided critical functional insights into the bacteria during a bloom event; however, it could not link function with phylogeny or individual populations . High-thSkeletonema sp. to Phaeocystis sp. algae was observed. Furthermore, we conducted metagenomic binning to obtain an extensive catalog of microbial genomes sampled across the succession process. We hypothesize that microbial change is a potential driving force for algal bloom species succession, which involves the changes in bacterial community structure and function. Based on this assumption, we aimed to (1) investigate the composition and succession of bacterioplankton communities associated with two different algal blooms; (2) identify potential core bacterial taxa that could be considered biomarkers for different algal bloom processes; (3) reveal the mechanism of algae-bacteria interactions during the bloom process and how the bacteria influence bloom development; and (4) illuminate the regulation mechanisms of algal bloom succession from a microbial perspective  and describe algae-bacteria interactions and roles in the mixed algal bloom process.Here, we have designed an artificial simulation experiment using plankton samples from the Shenzhen coastal waters and successfully induced an algal bloom in the laboratory, where a discernable succession phenomenon from 2.2.1.3 (8.83 × 10−4 M), NaH2PO4·2H2O (3.63 × 10−5 M), Na2SiO3·9H2O (1.07 × 10−4 M), and FeCl3·6H2O (1.16 × 10−5 M). During the experiment, all PBRs were exposed to artificial light at a surface irradiance of approximately 200 μE m−2 s−1 in a 12:12 h light–dark cycle, maintaining water temperature at 24 ± 1°C. For proper liquid circulation to avoid cell accumulation, each photobioreactor had an internal draught tube to achieve the flow pattern of an airlift loop. For gas injection, a ceramic diffuser was placed at the bottom of the photobioreactor to ensure sufficient gas supply. Air was continuously injected into the PBR at 0.1 l min−1 and a flow meter was installed to maintain the flow rate.An artificial algal bloom induction experiment was performed from 28 October 2020  to 26 November 2020 . The microcosm photobioreactor (PBR) (100 l) was designed according to previous methods . A total2.2.Algal biomass was monitored daily by sampling. Fifty-milliliter samples were collected daily from the PBRs to determine algal biomass. Part of the samples was fixed with 1% Lugol iodine for algal identification and quantification. The algal cells were observed and counted using a hemocytometer under an optical microscope (magnification × 100) .We divided the PBRs into three groups to obtain samples for metagenomic sequencing. Each sample collected from two PBRs was mixed as an independent biological replicate to satisfy the DNA extraction demands for metagenomic analysis. The sampling frequency was performed once every 2 days. The collected samples (2 l) were successively filtered through a 300-mesh plankton net to remove larger particles. Water samples were then filtered through a 3-μm fiber membrane  to collect the first subset of microorganisms . The filtrate was then passed through a 0.22-μm fiber membrane  to obtain the second subset . The filters were then flash-frozen in liquid nitrogen and stored at −80°C for subsequent DNA extraction.2.3.Total DNA was extracted from filters using a FastDNA Spin Kit  according to the manufacturer’s instructions. The concentration and purity of extracted DNA were determined with a TBS-380 Mini-Fluorometer  and a NanoDrop2000 Spectrophotometer , respectively. The DNA extract was fragmented to an average size of about 400 bp using Covaris M220  for paired-end library construction. Paired-end library was constructed using NEXTflex™ Rapid DNA-Seq . Paired-end sequencing was performed on an Illumina Hiseq instrument  at Majorbio Bio-Pharm Technology Co.  using HiSeq Reagent kits according to the manufacturer’s instructions.2.4.−5 using Diamond (v0.9.19) for metabolic pathway annotations  using fastp (version 0.20.0) . The resotations . To avoimapped reads is the number of the reads in the metagenome data that mapped to the reference sequence; Lreference sequence is the sequence length of the corresponding specific reference sequence; n is the number of reads belonging to the same subtype of the gene ; 150 is the sequence length of the Illumina reads; and Nmeta is the number of reads in the metagenome sequence data (10 million).where NClean reads were then used to obtain metagenome-assembled genomes (MAGs) using the metaWRAP Binning module (−maxbin2 –concoct –metabat2 options) . We cons2.5.The taxonomy of the high-quality MAGs (bins) was classified using GTDB-Tk v1.3.0 . MAGs we2.6.p values .The relative abundance of each MAG from the separate sample was used to estimate community composition. Bacterial community composition was visualized using principal coordinate analysis (PCoA) based on the Bray–Curtis dissimilarity metric. Permutational analysis of variance (PERMANOVA) was performed on community data using the vegan package . The relp values . To dete3.3.1.Skeletonema sp. and Phaeocystis sp., respectively. For the former, the cells were 2–12 μm in diameter and formed long chains, each containing up to 60 cells with highly variable intercellular distances. For the latter, the solitary cells, either flagellated or non-flagellated, were generally 2–8 μm in diameter. More commonly, most solitary cells formation colonies, which are composed of embedded mucus-encrusted cells up to 0.8 cm in diameter. The cell density of Skeletonema sp. ranged from 1.0 × 106 to 4.6 × 107 cells/L, with the highest biomass appearing at G7. During the Skeletonema bloom, time points G1, G5, and G9 represented the beginning, developmental, and death stages, respectively. Points G13 and G15 signified the transitional period in which a mixture of various algae coexisted. From the time point G15, Phaeocystis sp. became the dominant species, with a maximum abundance at G21 (5.01 × 107 cells/L). During the Phaeocystis bloom phase, points G15, G21, and G29 were the beginning, developmental, and death stages, respectively.3.2.Skeletonema sp. and Phaeocystis sp. blooms. In total, 389 bacterial MAGs were screened  for subsequent analysis , Bacteroidia (88), Gammaproteobacteria (73), Planctomycetes (31), Actinomycetia (16), Acidimicrobiia (12), Verrucomicrobiae (6), Phycisphaerae (5), Chlamydiia (4), UBA1135 (4), Saccharimonadia (3), Cyanobacteriia (3), Thermoleophilia (3), Candidatus Babeliae (2), Rhodothermia (2), Bacteriovoracia (1), Bacilli (1), UBA11346 (1), and Blastocatellia (1).Metagenomic assembly and binning were used for a genome-resolved analysis of ysis see . At the p. bloom . These b3.3.Skeletonema bloom, the pre-, onset- and post-stages of the bloom process were dominated by Thermoleophilia and Alphaproteobacteria, a single Alphaproteobacteria taxon, and Bacteroidia and Gammaproteobacteria, respectively. Unlike the Skeletonema bloom, Gammaproteobacteria and Bacteroidia were dominant during the entire Phaeocystis bloom period, although a few fluctuations were observed. An interesting phenomenon is that throughout the complete bloom succession process, Alphaproteobacteria showed a gradually decreasing trend, while Bacteroidia had a gradually increasing trend.A heat map was constructed based on the abundance of MAGs to show the relationship and reproducibility among the various samples in the two algal blooms . The MAGp < 0.05, The Shannon indices showed significant differences between the various bloom stages . The maxSkeletonema sp. and Phaeocystis sp. groups. All samples were clustered into two groups in the form of Skeletonema sp. and Phaeocystis sp. bloom stages (Skeletonema bloom phase (p < 0.05). Among these bins, bin.273, bin.15, bin.20, bin.317, and bin.291 belonged to the family of Rhodobacteraceae and constituted 24.58% (relative abundance) of the bacterial community. On the other hand, MAGs (mean proportion > 2%) of bin.202, bin.339, bin.18, bin.249, bin.369, bin.37, and bin.163 were significantly enriched in the Phaeocystis sp. phase (p < 0.05). Among these, bin.339, bin.249, and bin.369 belonged to the family of Flavobacteriaceae and comprised 17.36% (relative abundance) of the bacterial community. The MAG of bin.202 was classified as the genus Phaeodactylibacter in the family of Saprospiraceae and accounted for 10.47% (relative abundance) of the bacterial community.For the beta diversity, the PCoA plot  indicated that samples were divided into m stages . Howeverm stages . The res3.4.LEfSe analysis was used to identify differentially abundant metagenome functions  among the six stages of the successional process . Taken tSkeletonema bloom stage. On the other hand, metabolic pathways, biosynthesis of secondary metabolites, starch and sucrose metabolism, amino sugar and nucleotide sugar metabolism, glycolysis, citrate cycle (TCA cycle), tryptophan biosynthesis, biotin metabolism, thiamine metabolism, vancomycin resistance, streptomycin biosynthesis, flagellar assembly, and bacterial secretion system were increased in the Phaeocystis bloom stage. Essentially, the algal bloom period consisted of time points G5 and G21 that served as stabilization (middle-stages) periods for Skeletonema sp. and Phaeocystis blooms, respectively. The middle-stage of the Skeletonema bloom had the highest abundance of QS, tryptophan metabolism, sulfur metabolism, and porphyrin metabolism. Moreover, tryptophan biosynthesis, biotin metabolism, and thiamine metabolism had the highest abundance in the middle-stage of the Phaeocystis bloom. These results confirm that the functional capabilities of microorganisms were strongly related to algal bloom succession.According to the LEfSe results, some metabolic pathways were significantly enriched during the bloom succession process . The relAccording to previous studies, signal regulation  and substance metabolism, especially medium substance between algae and bacteria such as DMSP and VB, are often used as key clues in the study of algae-bacteria interactions . In the 3.5.Alphaproteobacteria (60 MAGs) and Gammaproteobacteria (13 MAGs) were identified as containing the SOX systems. Regarding the organosulfur DMSP metabolic pathway, most MAGs were identified as containing the cleavage pathway key gene dddP (K01271) or dddL (K16953), such as MAGs of Alphaproteobacteria, and a few had the demethylation pathway key gene dmdA (K17486)  . The MAG3.6.12), thiamine (B1), and biotin (B7) in the MAGs were investigated  were capable to synthesize vitamin B7; Gammaproteobacteria were able to synthesize vitamins B1 and B7; and Alphaproteobacteria  encoded the essential genes necessary for the biosynthesis of vitamins B1, B7, and B12. In the Skeletonema sp. phase, multiple species were capable in various VB biosynthesis, such as bin.171 for VB12, bin.188 for VB1 and VB7, and bin.20, bin.273, and bin.317 for VB1/VB7/VB12. Bacteria in the Phaeocystis bloom were capable of vitamin B7 production, including bin.202, bin.249, and bin.339. Our results suggest that the two algal blooms had different VB requirements, and the microorganisms might have provided vitamins for their host.Functional difference analysis revealed that vitamin synthesis was significantly different between the two bloom stages , 6. To dstigated . The res3.7.Acidimicrobiia and Bacteroidia. Some MAGs belonging to Alphaproteobacteria, such as the Roseobacter clade strains of bin.273, bin.15, bin.20, bin.317, and bin.291, had more QS signaling synthesis systems and covered almost all of the mentioned QS signaling molecules. In the Skeletonema sp. phase, AI-1 synthesis was present in bin.171, bin.188, bin.273, bin.366, and bin.368. Conversely, in the Phaeocystis sp. phase, the main taxa (bin.202 and bin.339) were involved in the DSF and PQS signals. Overall, different biosynthetic pathways for the synthesis of QS molecules were present during the different phases of the bloom, with AI-1 pathways mostly represented during the Skeletonema sp. phase and AI-2 and other biosynthetic pathways in the Phaeocystis sp. phase.The indicator functional composition analysis identified QS-related pathways were significantly different during the succession , 6. To oSkeletonema sp. and Phaeocystis blooms, respectively  and Alphaproteobacteria  had the complete pathways to convert tryptophan to indole-3-acetamide (required gene K00466) and then to IAA (required gene K01426). The bin.273 and some MAGs in the class of Bacteroidia were regarded as containing the genes involved in the biosynthesis of IAA, where tryptamine (required gene K01593) was converted to indole-3-acetaldehyde (required gene K00274) and then to IAA (required gene K00128). In the two algal blooms, the genes involved in the biosynthesis of the IAA appeared in the pre-and onset stage and were identified as belonging to different bacteria . Based on the fact that IAA appeared in the early stage of algal bloom shows that IAA could play a certain role in promoting the formation of algal blooms.In addition to QS, IAA was also an important signal regulator. Differential functional analysis showed that the genes involved in the tryptophan metabolism and biosynthesis were represented by ectively , 6. Trypectively . The res4.Skeletonema sp. and Phaeocystis sp. play important roles in elemental cycles, marine food webs, and potential climate change  to produce ammonium, which then the ammonium serves as a nitrogen source for the diatoms. This process might help regulate organism-specific metabolic interactions to establish and stabilize associations with photoautotrophic diatoms  are commonly associated with the bloom development of the Phaeocystis population  metabolism, degrading algae-derived compounds  along with the production of the climate-relevant gas, dimethyl sulfide (DMS)  was the dominance of the de (DMS) . DMS cande (DMS) . Roseobaractions .Accordant with the results mentioned above, we suggest that microbes are ecological regulators for algae that affect the state of the host algae and promote their succession by nutrient exchange and signal communication. However, it is worth noting that many challenges still exist in directly linking bacterial lineages to algal succession . The isoTo gain more insight into the impact of these bacteria on algal bloom succession, the MAGs were reconstructed and functionally annotated . We obseAlphaproteobacteria had more QS signaling synthesis systems and covered almost all the mentioned QS signaling molecular synthesis systems  of the Phaeocystis bloom period were primarily DSF and PQS. Taken together, these results reconfirm that QS may participate in affecting bloom succession by regulating the microbial behavior and available algal nutrients  or dddL (K16953) from Alphaproteobacteria involved in this pathway in bin.15, bin.20, bin.273, and bin.317 in the Skeletonema bloom period. In addition, the demethylation pathway key gene dmdA (K17486) was also identified in bin.317, bin.291, and bin.20  can be found at: Ethical review and approval were not required for the study on human participants following the local legislation and institutional requirements. Written informed consent for participation was not required for this study following the national legislation and the institutional requirements.JMZ and JNZ: conceptualization, investigation, writing-original draft preparation, statistical analysis, software application, and figures drawing. ST and KC: data analysis. GC and ZC: read and revised the manuscript, funding acquisition, and project administration. All authors contributed to the article and approved the submitted version.This work was supported by the National Natural Science Foundation of China (41976126), Guangdong Basic and Applied Basic Research Foundation (2020B1515120012), Shenzhen Science and Technology Program (Grant No. RCJC20200714114433069), S&T Projects of Shenzhen Science and Technology Innovation Committee , Project of Shenzhen Municipal Bureau of Planning and Natural Resources (Grant No. [2021]735–927), Shenzhen-Hong Kong-Macao Joint S&T Project (pending number 202205303000176), as well as Shandong Provincial Natural Science Foundation, China (ZR2020MD081).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Dear reader,Since 2009, when Prof. Dr. Álvaro Nagib Atallah and I accepted the challenge of leading the Scientific Department of Associação Paulista de Medicina (APM), I have had the privilege of also taking on the function of editor of the journals of this entity: São Paulo Medical Journal and Diagnóstico & Tratamento.From the outset, this was seen to be an arduous task that would certainly be greater than any prediction that we might have made. We discovered that fulfilling this task with the deserved quality was only saved from being impossible thanks to the support and collaboration of a multiprofessional team that dedicated itself to the APM every day. This team became ever more professional as time went by, with the aim of providing our association with the best resources available in all areas. After completing six years of leading this undertaking (three years as Adjunct Director and three years as Director), the time has come to "pass the baton", by handing over this position that I have served with pride and dedication. Nonetheless, this is not just a moment of farewell but, rather, a moment of renewal, and for this reason I would like to reflect on what has been achieved.Specifically with regard to the São Paulo Medical Journal, the most important objective was to raise the relevance of the journal within the international scenario, without losing its focus on dissemination of general medical knowledge. In other words, we sought articles for the journal that would have high quality and scientific rigor, but without transforming the journal into something very specialized or that might cause habitual readers of the journal to drift away. The crowning moment of this work was certainly when, for the first time, the São Paulo Medical Journal obtained a designated impact factor from Thompson Reuters.In relation to Diagnóstico & Tratamento, we maintained the premise of disseminating medical knowledge in a wide-ranging manner through sections dedicated to specialties  and the sections Patient-Oriented Evidence that Matters (POEMs), Evidence-Based Medicine, Language, Residency and Medical Teaching, General Interest, Opinion and Cochrane Highlights.At the helm of the Scientific Department, where I initially held the position of Adjunct Scientific Director until 2012 and then Scientific Director until the present date, I sought to encourage initiatives that would bring greater dynamism and penetration for the APM. One successful example of this is the Student Medical Congress, which was first held in 2009 and translated very well our intention to interact with physicians from the time of their graduation onwards, by stimulating them and assisting them in their technical and scientific development.Other activities of the Scientific Department that deserve highlighting are the interaction and partnerships with health departments and universities that have had the aim of developing medical teaching and scientific updating. Building ties with specialty societies was a partially achieved objective, and this will certainly end up being consolidated through the work of the next board of directors. I would like to conclude by thanking all of those involved in the journal's editorial process, the entire board of directors of the Associação Paulista de Medicina and, especially, our readers, who are the major motive for our work.


Non-native language scholars often struggle to choose between English and their native language in scholarly publishing. This study aims to identify the mechanism by which journal attributes influence language choice by investigating the perspectives of 18 Chinese scholars through semi-structured interviews. Drawing on grounded theory, this study develops a model for how journal attributes influence researchers’ language preferences. We find that journal attributes influence researchers’ perceived value which, in turn, affects their particular language choice, with contextual factors playing a moderating role. By examining the motivations underlying Chinese scholars’ language choice, this study provides a critical understanding of the factors shaping their decision-making processes. These findings have significant implications for Chinese scholars, policymakers, and journal operators, shedding light on the issue of discrimination in academic publishing. Addressing these concerns is crucial for fostering a fair and inclusive academic environment. Moreover, English is the predominant language used for writing and publishing a large body of academic research and literature. Publications in languages other than English suffer from discrimination when their scientific output is evaluated based on the number of citations in citation databases .Natural science fields and university settings are becoming increasingly globalized, and to reach the greatest number of their fellow academics, scholars face pressure to publish their work in the most widely used language. In contrast, those employed in non-academic settings are more likely to aim to engage local policymakers and audiences . FurtherThe large number of papers published in international journals, i.e., English-language academic papers, is detrimental not only to the local dissemination of academic research but also to the development of native-language publications . AccordiScholars, especially those from non-English-speaking countries, have attached great importance to the study of academic language. However, existing studies have mainly focused on analyzing the motivation of academic language choice  and the Therefore, this study aims to explore the mechanisms behind choosing the language of academic papers through respondents’ perceptions of journal attributes, based on grounded theory analysis. Through this study, we further investigate the influencing factors and their structural relationships, providing relevant strategies for policymakers to encourage more researchers to publish articles in different languages.2.The factors that influence authors’ choice of journal can be divided into three categories: author attributes, journal attributes, and other research attributes . Author Currently, research on the choice of language for academic papers mainly focuses on the motivations or attitudes of non-native English-speaking researchers toward language selection. From the perspective of expectancy-value theory, scholars have studied the impact of perceived usefulness, intrinsic value, self-efficacy, and the cost of publishing in a particular language on language selection . Others Overall, non-native English-speaking scholars are influenced by various factors when choosing between English and their native languages for publication. There is also a range of “ecological variables” such as country, institution, and disciplinary background that can affect language choice . The maj3.3.1.Grounded theory is an exploratory research method proposed by The main reason for choosing grounded theory as the research method is that relevant theoretical research on the willingness, concepts, and mechanisms of language choice for publication has not yet matured. Therefore, this study adopted grounded theory, initially based on a literature review and theoretical sampling, to extract judgments and perceptions regarding the factors influencing publication language choice. Subsequently, we constructed a theoretical model framework based on the original data, as per the grounded theory approach.3.2.The main instrument used for data collection was in-depth interviews. First, a semi-structured interview guide with open-ended items was created based on a literature review and case studies. Second, two research professors with interview experience were invited to assess our interview guide questions. The interview questions were then improved and changed in response to the expert panel feedback and suggestions. The modified interview guide questions were as follows: (1) Why did you choose to publish some of your papers in English? (2) How did you begin working on an English-language paper? (3) What difficulties did you face when writing and publishing in English? (4) Why did you choose to publish some of your papers in Chinese? (5) What difficulties were encountered in writing and publishing in Chinese? (6) What types of emotional differences exist between writing papers in Chinese and English? (7) What language would you prefer to use when publishing your next paper?3.3.Eighteen participants were recruited between September and November 2022. They comprised 11 women and 7 men who had all published papers in both English and Chinese in the past 5 years. The interviewees were Ph.D. teachers with research interests covering science and the humanities. Their ages ranged from their mid-twenties to mid-thirties, with an average age of 28 years. The interviewees had diverse professional backgrounds, were amid a career upswing, and had been highly productive in scientific research in the last 5 years. Hence, the interviewees were in a good position to provide valuable insights into the topic under investigation.Personal in-depth interviews were conducted with all 18 interviewees, each lasting at least 30 min. During the one-on-one interviews, interviewees were given sufficient time to reflect before responding, and interviewers could adjust the questions to uncover deeper influencing factors, thereby gaining a more comprehensive understanding of the attributes that affect their language choices. With participants’ consent, the interview content was recorded, archived, and later transcribed. Fifteen randomly selected interview transcripts were coded, while the remaining three were used to test for saturation. 3.4.3.4.1.The purpose of open coding is to abstract and conceptualize raw data. By carefully reading and analyzing the content of each sentence word-by-word, the underlying values and meanings were labeled with concepts. Through repeated comparisons, original statements that described the same concept and appeared more than three times were conceptualized and categorized. Eventually, they were summarized into 34 initial concepts and 17 initial categories, as shown in 3.4.2.Building on the open coding, we differentiated between core and subcategories by repeatedly categorizing and adjusting similar categories based on their logical relationships and sequencing. Through this process, four core categories and nine subcategories were identified see .3.4.3.Integration involves the consolidation of categories around a central category, and the subsequent refinement and streamlining of the resulting theoretical framework , p. 351.To ensure the systematic construction of the theory, a theoretical saturation test was conducted on the coding results to determine that there were no new categories that could be explored in the analysis of the 15 interview records. Furthermore, grounded analysis was conducted on three randomly selected interview materials, which did not produce any new concepts or associative relationships; thus, all steps were ultimately terminated, and it was confirmed that our model of the impact of journal attributes on researchers’ language choice had reached saturation.4.The results of this study demonstrate the mechanism of language selection by Chinese scholars for their academic papers. The results show that: first, journal attributes influence researchers’ perceived value. Second, perceived value affects language choice. Third, contextual factors play a moderating role. The main findings and related discussions are now presented in more detail.4.1.Based on an analysis of the interviews and relevant literature, this article defines journal attributes as the inherent characteristics of journals as knowledge dissemination media , which iJournal indicators mainly include quantitative and impact indicators. Quantitative indicators refer to objective quantitative data on journal and article output. Impact indicators reflect the dissemination status of journal information, i.e., the degree to which the journal is read, referenced, cited, and used by readers after publication, including journal impact factor, citation frequency, reference quantity, and audience. Some studies have shown that the most important factors influencing authors’ choices of different journals are journal reputation, audience, and journal impact factor . PublicaWriting research articles requires not only academic normativity but also writing skills. However, for non-native English-speaking scholars, writing research articles in English requires more time and effort. Accordingly, publishing in English may place an additional burden on them . The proJournal feedback attributes include the effectiveness, timeliness, and professionalism of feedback. The effectiveness of feedback was evaluated based on the quality of replies, review comments, and related services provided by the journal. The effectiveness of reviewers’ comments and the helpfulness of editors’ replies are significant deciding factors . The timIn general, the analysis results indicate that the indicators, specifications, and feedback attributes of journals affect authors’ perceived cost value, perceived return value, and perceived connectivity value.4.2.Perceived value has been studied extensively in the field of marketing, and there is a lot of research on the influence of perceived value on willingness to pay; however, little research has been conducted on the intention to choose a publication language. From the analysis of the coding results, perceived value can be defined as the subjective evaluation or cognition of the balance between the benefits perceived by researchers and the costs they pay when obtaining services, including perceived cost value, perceived return value, and perceived connectivity value .Perceived cost value includes monetary, time, and emotional costs . AccordiDriven by their pursuit of academic job prospects, promotions, and tenure, they meticulously select the best-fitting journals . Seven iPerceived connectivity value includes social reputation and international communication. Five interviewees believed that perceived connectivity value has an impact on their language selection preference, such as “sharing my research results with international scholars will get a more comprehensive evaluation, so I prefer to publish in English.”The results indicate that perceived value mediates the relationship between journal attributes and language choice for publishing. No previous studies have examined the mediating effect of perceived value on article language choice. These findings thus extend our knowledge of the mechanisms underlying publishing language choice.4.3.Context, also known as situation or circumstance, is related to the factors of the subject and the political, economic, legal, ideological, and physical environment in which they exist . In thisThe reviewed studies provide evidence that publication requirements and regulations prescribed by government agencies or affiliated institutions affect authors’ journal selection . Nine inBased on the interview content, more than half of the participants believed that physical context played an important role in influencing their language choice for academic papers based on perceived value. For example, one participant stated, “Using the mother tongue to publish papers should save a lot of time and effort, but because none of the senior students in our lab write in Chinese, it has become a default that we all have to write in English. So, I am more willing to publish in English and not be an outlier” . Another participant mentioned, “Writing papers in English can help with job promotions, but since all of my co-authors are Chinese and we communicate in Chinese rather than English, I am more willing to publish in Chinese” . Another participant mentioned, “English papers not only have high international recognition, but also our peers evaluate academic abilities based on the number of English papers published. Therefore, I am more willing to publish in English” .In summary, this study argues that situational factors play a moderating role in the influence of perceived value on researchers’ specific language choice for their academic papers.5.Based on grounded theory, this paper has constructed concepts linking journal attributes, perceived value, contextual factors, and researchers’ language choice, and then proposed a theoretical model of the mechanism by which journal attributes affect researchers’ academic language choice. The model reveals the internal paths through which journal attributes affect perceived value, perceived value affects language selection, and contextual factors play a moderating role in the relationship between perceived value and academic language choice. In conclusion, the research findings are significant because they shed new light on the factors that influence Chinese researchers’ choice of publishing language from a perceived value perspective. Accordingly, this study provides suggestions for policymakers and journal operators when developing policies for language use and operating journals as follows.(1) It is important to develop strategies to strengthen the influence of journal attributes. First, the journal should be disseminated through various marketing channels to increase its influence. The higher the influence of the journal, the higher the perceived value for researchers. Second, the scope of the journal’s content should be broadened and high-quality content should be selected to provide authoritative, professional, diverse, and in-depth material to readers . ThirdlyAlthough this study provides insights and references on the relationship between journal attributes and researchers’ language preferences, there are some limitations that need to be addressed. First, this study constructs a theoretical model based on a literature review and interview data but does not validate the model through empirical evidence. The reliability and validity of the impact model constructed based on grounded theory must be further tested. Future research should develop scales for each variable and conduct more detailed empirical studies to improve the universality of the theoretical research. Second, the number of interviewees in the study was limited. Although our analysis passed the theoretical saturation test, researchers from all disciplines and ages were not included. In future, researchers should collect more meaningful data to clarify the influence of the individual characteristics of researchers from different academic backgrounds and qualifications on their language preference for papers.The original contributions presented in the study are included in the article/Studies involving human participants were reviewed and approved by the Ethics Committee of School of Business and Management, Jilin University. All the participants provided written informed consent to participate in this study.JC performed the data analyses and wrote the manuscript. CQ helped perform the analyses through constructive discussion. ZW contributed to the implementation of the methods and manuscript preparation. All the authors contributed to the manuscript and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Glucose-6-phosphate dehydrogenase (G6PDH) catalyses the rate limiting first step of the oxidative part of the pentose phosphate pathway (PPP), which has a crucial function in providing NADPH for antioxidative defence and reductive biosyntheses. To explore the potential of the new G6PDH inhibitor G6PDi-1 to affect astrocytic metabolism, we investigated the consequences of an application of G6PDi-1 to cultured primary rat astrocytes. G6PDi-1 efficiently inhibited G6PDH activity in lysates of astrocyte cultures. Half-maximal inhibition was observed for 100 nM G6PDi-1, while presence of almost 10 µM of the frequently used G6PDH inhibitor dehydroepiandrosterone was needed to inhibit G6PDH in cell lysates by 50%. Application of G6PDi-1 in concentrations of up to 100 µM to astrocytes in culture for up to 6 h did not affect cell viability nor cellular glucose consumption, lactate production, basal glutathione (GSH) export or the high basal cellular ratio of GSH to glutathione disulfide (GSSG). In contrast, G6PDi-1 drastically affected astrocytic pathways that depend on the PPP-mediated supply of NADPH, such as the NAD(P)H quinone oxidoreductase (NQO1)-mediated WST1 reduction and the glutathione reductase-mediated regeneration of GSH from GSSG. These metabolic pathways were lowered by G6PDi-1 in a concentration-dependent manner in viable astrocytes with half-maximal effects observed for concentrations between 3 and 6 µM. The data presented demonstrate that G6PDi-1 efficiently inhibits the activity of astrocytic G6PDH and impairs specifically those metabolic processes that depend on the PPP-mediated regeneration of NADPH in cultured astrocytes. The iniposthoc test. The level of significance is indicated by asterisks or hashes . p-values above 0.05 were considered as not significant.All data are presented are means ± standard deviations (SD) of values that are derived from experiments that have been performed on at least three independently prepared astrocyte cultures. The significance of differences between two data sets were analysed with a t-test and three or more data sets were analysed for significance by ANOVA followed by the Bonferroni To test for the potential of G6PDi-1 to inhibit astrocytic G6PDH, astrocyte primary cultures were lysed in hypotonic buffer and the soluble lysate supernatant was used for determination of G6PDH activity in the absence or the presence of G6PDi-1 . These results are consistent with the reported [Preliminary experiments on the G6P-dependence of the G6PDH activity revealed for the enzyme in lysates of astrocytes a hyperbolic Michaelis-Menten type correlation with a Kreported  non-compG6PDi-1 lowered the detectable activity of G6PDH in lysates of astrocytes almost completely in a concentration of 100 µM  that was observed for a treatment with 100 µM G6PDi-1 Fig. . The datG6PDi-1 has recently been reported and characterized as efficient inhibitor of purified human G6PDH and of G6PDH-dependent processes in peripheral cells . Here we+ [Comparison of the inhibitory potential of G6PDi-1 on astrocytic G6PDH with that of DHEA and 6AN revealed that DHEA had to be present in 100fold higher concentration than G6PDi-1 to inhibit G6PDH by 50%, while 6AN even in a concentration of 100 µM did not show any G6PDH inhibition. The lower power of DHEA to inhibit G6PDH, compared to G6PDi-1, confirms literature data . Also th+ . Thus, aInvestigation of potential inhibitory effects of G6PDi-1 on other enzymes that either produce NADPH (6PGDH) or consume NADPH (GR and NQO1) revealed that G6PDi-1, even if applied in a high concentration of 100 µM, hardly affected the other enzymes. Thus, G6PDi-1 appears to be a highly potent and specific inhibitor of astrocytic G6PDH and was therefore tested in further experiments for its potential to affect PPP-dependent processes in cultured astrocytes.Application of G6PDi-1 to astrocyte cultures revealed that G6PDi-1 does not compromise cell viability, but strongly affects cellular processes that depend on PPP-mediated NADPH regeneration already in low micromolar concentrations, such as the NQO1-dependent WST1 reduction and the GR-dependent GSSG reduction. The presence of G6PDi-1 impaired the glucose-dependent astrocytic β-lapachone-mediated WST1 reduction in a concentration-dependent manner, a process that uses NADPH provided via the PPP as electron donor for the enzyme NQO1 to reduce the redox cycler β-lapachone . In contPPP-derived NADPH is also required for the GSH regeneration from GSSG by GR in astrocytes , 38 and During extended exposure of astrocytes to β-lapachone in the presence of G6PDi-1 cellular GSH and GSSG disappeared and GSSG accumulated extracellularly. These processes are caused by the strongly elevated cellular GSSG level that facilitates the export of GSSG via the multidrug resistance protein (Mrp) 1 –49.+-dependent isocitrate dehydrogenase [Application of G6PDi-1 to unstressed cultured astrocytes revealed that presence of the inhibitor in concentrations of up to 100 µM does not affect the basal glycolytic lactate production by astrocytes nor the cell viability for incubations of up to 6 h, demonstrating the low toxic potential of G6PDi-1 for the conditions investigated. Such a low toxic potential was expected, as the PPP contributes in unstressed astrocytes less than 10%  to the grogenase  and malirogenase  could coIn conclusion, G6PDi-1 in concentrations of up to 100 µM does not compromise cell viability or basal GSH metabolism of cultured rat astrocytes nor glycolytic lactate production, but efficiently impairs already in low micromolar concentrations metabolic processes that depend on the regeneration of cytosolic NADPH by G6PDH and the PPP. G6PDi-1 appears to be a highly potent and rather specific inhibitor of G6PDH that should be considered as suitable tool for studies investigating potential involvement of NADPH regeneration by G6PDH and/or functions of the oxidative part of the PPP in brain cells. Application of G6PDi-1 is likely to be a good alternative to other established PPP inhibitors such as DHEA or 6AN, that have previously been used to target G6PDH or the PPP activity in brain cells , 23–27.


Kidney Transplantation is the preferred treatment for most patients with end-stage renal disease (ESRD) . DespiteBiomarkers are biomolecules found in body fluids or tissues. Traditional monitoring after renal transplantation includes the continuous measurement of serum creatinine (Scr), estimated glomerular filtration rate (eGFR), blood concentration of immunosuppressive drugs, donor specific antibody (DSA) monitoring, virus quantity detection, and so on. However, they often reflect advanced tissue damage and have limited ability to accurately detect SCR. Recent advances in high-throughput molecular biotechnologies and bioinformatics have now made it possible to in-depth analysis of kidney allograft rejection and response to treatment. Accordingly, new biomarkers can be identified and validated by non-invasive or minimal-invasive approaches. And the discovery of novel biomarkers as reported in this collection raised new hope for early detection and development of promising new treatment approaches.Li et al. include LASSO, random forest, and support vector machines. Six hub genes  were identified as potential predictors of acute kidney injury. These genes can be used as a new tool for early diagnosis of AKI.Most transplanted kidneys come from deceased donors and inevitably experience ischemia reperfusion injury, which may lead to AKI and affect the recovery of renal function after surgery. Three machine learning algorithms used the study by Raïch-Regué et al. used immunohistochemistry to show that p-S6RP in the peritubular capillary endothelia was associated with circulating human leukocyte antigens (HLA)-DSA in transplanted kidney tissue biopsies and first suggested that it could be used as a sensitive alternative biomarker for HLA-DSA to diagnose ABMR when DSA was not available or not yet detected. Renal operational tolerance, defined as the condition in which a SOT recipient retains stable graft function and lacks histological signs of rejection, after at least 1 year of immunosuppressant discontinuation  can be used to distinguish the origin of cfDNA, so that donor derived cell free DNA (dd-cfDNA) can be widely used to detect the early graft function status  and T cell-mediated rejection (TCMR) can significantly lead to deterioration of graft function and eventually graft loss. Currently, complement activation in the form of C4d deposits in peritubular capillaries (PTC) is used as an ABMR marker  is that it can identify different immune cells in the graft kidney, which is of great significance to explore the changes both in number and function of macrophages , T cellsIn conclusion, identification of earlier diagnostic biomarkers will not only allows designing individualized therapy for timely therapeutic intervention, but also further advance understanding of pathgeneisis of kidney allograft rejection. The field has been evolving rapidly; substantial prograss has been made over the last decade. It is conceivable that as the number of clinical studies using omics and other innovative approaches continues to increase, biomarkers with high sensitivity and specificity will be identified and vlidatated in the next few years, thus guiding the development of early preventive treatment strategies for clinical applications.XD wrote and revised the editorial. XH and ZZ revised the editorial. All authors reviewed the manuscripts submitted to the Research Topic and the final version of this editorial. All authors contributed to the article and approved the submitted version.


Primary cutaneous melanoma (PCM) is the most aggressive skin malignancy, with an increasing incidence and significant mortality. Tumoral invasion, expressed as Breslow thickness, is routinely assessed on hematoxylin and eosin (HE), although this stain may sometimes underestimate the tumoral depth. The aim of this study was to compare the efficiency of the immunohistochemical (IHC) markers S-100, SOX10, Melan-A, and HMB-45 with HE for the evaluation of the Breslow thickness and staging of PCM. This retrospective study included 46 cases of PCM diagnosed between 2015 and 2022; for each case, the Breslow thickness using HE, S-100, SOX10, Melan-A, and HMB-45 was measured and the appropriate T category was recorded. The highest values of the Breslow thickness were observed for S-100. However, S-100, SOX10, and Melan-A provided statistically significant higher values of the Breslow thickness compared to HE, but no difference was noted between HMB-45 and HE. S-100 was most frequently involved in increasing the T category (26.1%), the majority of cases being upstaged from T1a to T1b. The IHC markers S-100, SOX10, and Melan-A contributed to better evaluation of the melanoma invasion, especially in thin melanomas, but their impact on staging and consecutive treatment remains to be confirmed by future studies. Primary cutaneous melanoma (PCM) originates from melanocytes, which are cells located in the basal layer of the epidermis and in hair follicles and responsible for producing melanin . DespiteDespite interobserver discrepancies, the Breslow thickness is the most reproducible histopathological parameter, with vital importance for melanoma staging and prognosis, and is used to define surgical excision margins and indicate the necessity for sentinel lymph node biopsy ,13,14,15Hematoxylin and eosin (HE) is the standard stain for the evaluation of the Breslow thickness, but it can sometimes lead to overlooking isolated tumoral cells located in the dermis, or it can underestimate the tumoral invasion in cases associated with regression ,20,21. AThis retrospective study was conducted in the Department of Pathology of the County Clinical Hospital Mureș between January 2021 and June 2022 and included all cases of PCM diagnosed in this department beginning in 2015. The criteria for inclusion in the study were invasive melanoma with complete IHC profile . The following exclusion criteria were applied: metastatic or desmoplastic melanoma, inadequate depth of the biopsy specimen, local re-excisions, PCMs associated with a nevus, and uninterpretable IHC reactions. The study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of the hospital (protocol number 16381/06.01.2021). For each case, five slides with 3 µm thickness were selected, stained with HE, S-100 , SOX10 , HMB-45 , and Melan-A . Furthermore, all sections had previously been obtained from the same paraffin block. The process of case selection is illustrated in The specimens were coded, randomized, and then reevaluated with an optical microscope  in a single-blind manner by an experienced senior dermatopathologist (O.S.C.), who had been evaluated for intraobserver reliability . The Breslow thickness and the Clark level of invasion were recorded for each case. The Breslow thickness was measured from the top of the granular layer or the base of the ulceration to the deepest situated tumoral cell. PCMs located exclusively in the dermis were measured in a standard manner (from the top of the granular layer of the epidermis). The Breslow thickness was evaluated with the ×5 objective, and the isolated tumoral cells located in the dermis were identified with the ×20 objective. The Breslow thickness was measured using ZEN Blue software , with a precision of 0.1 mm, as recommended by the 8th edition of the AJCC staging system. Tumors with a thickness ≤1 mm were evaluated with 0.01 mm precision but the result was rounded to a single decimal. After the measurement of the Breslow thickness on the 5 histological sections, the appropriate T category was recorded for each case. p < 0.05 (two-tailed) with a 95% confidence interval. The patients’ demographic data were assessed using descriptive statistics . The histopathological parameters were statistically analyzed using GraphPad Prism 7 software . Continuous variables were presented as mean ± standard deviation for normally distributed data and as medians for non-normally distributed data, respectively. Categorical variables were reported as numbers and percentages. Data were evaluated for normal distribution based on the Kolmogorov-Smirnov test and then were statistically analyzed using the Friedman test. A post hoc analysis was performed using Dunn’s multiple comparisons test. The kappa coefficient was used for evaluation of the agreement rate between the applied staining techniques in the staging of PCM. The level of statistical significance was set at a value of This retrospective study included 46 cases of PCM diagnosed between 2015 and 2022, in 25 men (54.3%) and 21 women (45.7%) with a mean age of 61.7 ± 17.4 years (range 25–84). Important histopathological data are summarized in The Breslow thickness values categorized according to the 8th edition of the AJCC criteria are presented in p < 0.0001). The lowest Breslow thickness values were recorded for HE and HMB-45 and the highest for S-100 (A detailed description of the 46 cases included in the study is presented in or S-100 .p < 0.001). Moreover, the values obtained with S-100 were also significantly higher than those obtained with HMB-45 (p < 0.001) and Melan-A (p < 0.05). The values recorded with HMB-45 did not significantly differ from those recorded with HE (p > 0.05). There was no significant difference between SOX10 and the markers S-100 and Melan-A (p > 0.05)  .The variation of the Breslow thickness obtained with HE and the IHC markers is illustrated in The agreement rates between the T categories obtained based on HE staining and IHC techniques are summarized in The kappa correlation coefficients were interpreted as follows: substantial for S-100 (0.601) and SOX10 (0.627) and very good for HMB-45 (0.896) and Melan-A (0.813). Upstaging was noted in 12 cases (26.1%) after applying S-100, in 9 cases (19.6%) after applying SOX10, in 2 cases (4.3%) after applying HMB-45, and in 3 cases (6.5%) after applying Melan-A.Our results showed that the Breslow thicknesses obtained with the IHC markers S-100, SOX10, and Melan-A had statistically significant higher values than those obtained with HE. Moreover, the combined use of the four studied IHC markers found a deeper tumoral invasion in 63% of the lesions, therefore rejecting the null hypothesis. Regarding the T category, the most frequent upstaging was based on S-100 and mostly occurred from T1a to T1b. This may have major implications in clinical practice, as patients with T1b melanoma can be candidates for sentinel lymph node biopsy, with an important impact on their diagnosis and treatment ,25. The In a study published in 2019, Bishop and Tallon  comparedp > 0.05 for the values of the Breslow thickness measured based on SOX10 and Melan-A). Melan-A can aid in the identification of isolated tumoral melanocytes located in the dermis, which can upstage a previously diagnosed melanoma in situ with HE to an invasive lesion. Drabeni et al. [Among the many proposed IHC markers used in the diagnosis of PCM, S-100, SOX10, Melan-A, and HMB-45 are frequently applied ,38. The i et al.  found a i et al.  reportedi et al. . SOX10 ei et al. . Furtherp < 0.001), SOX 10 (p < 0.01), and Melan-A (p < 0.05), which is in accordance with the findings of Kamyab-Hesary et al. [Based on our results, we identified statistically significant higher values of Breslow thickness using the more sensitive IHC markers S-100 (y et al. . Recently et al. . MITF way et al. .However, despite their possible contribution to the improvement of the tumoral depth evaluation, the role of the IHC markers in the staging and, consecutively, in the treatment planing of PCM remains a matter of debate, as all currently available treatment strategies and prognostic models rely on histopathologic assessment of the tumoral invasion based on the standard staining with HE .The importance of our study rests in the simultaneous evaluation of the Breslow thicknesss using four widely applied immunohistochemical markers for melanoma diagnosis, compared to other studies that included fewer immunohistochemical markers. Furthermore, almost half of the the selected cases were thin melanomas, in which the precise evaluation of the tumor inavasion is difficult. However, the statistical power of our study is limited by the small sample, originating from a single tertiary center. Moreover, the clinical relevance of the study could have been enhanced by a correlation with the clinical evolution of the patients regarding the occurrence of nodal or distant metastasis. The evaluation of the Breslow thickness exclusively using HE may underestimate the real depth of the tumoral invasion, especially in thin melanomas. Out of the IHC markers included in our research, S-100, SOX10, and Melan-A contributed to a more precise assessment of the tumoral thickness; however, their impact in clinical practice remains to be confirmed by large-scale, multicentric studies.


Using the diaphragm-type air spring as the research object. The ratio of the vertical stiffness change caused by compressed air to the total vertical stiffness change was calculated, and it was determined that the nonlinearity of air spring vertical stiffness was mainly caused by the deformation stiffness of the rubber airbag. The variation law of vertical dynamic stiffness of air spring was predicted by theory: due to the material's viscoelasticity, the vertical dynamic stiffness rises as the excitation frequency rises, and the vertical dynamic stiffness decreases with the increase of excitation amplitude due to the damping of the material. An air spring finite element analysis (FEA) and experiment were conducted. The results show that the vertical dynamic stiffness obtained through simulation and experiment is consistent with the theoretical prediction, when various factors such as material nonlinearity, element coupling, and stiffness value sensitivity were considered. This proves that the predicted vertical dynamic stiffness variation law is reliable. The vertical dynamic stiffness obtained from both simulation and experiment showed a strong correlation in numerical values, which verified the accuracy of the FEA model of air spring established in this paper. Due to its reasonable nonlinear elastic properties, low vibration frequency, effective energy absorption rate, adjustable stiffness characteristics for optimum driving comfort, and other benefits, air springs are popular among automakers and consumers. Air suspension is available on vehicles like the NIO ES8, Audi A8, Hong Qi HS7, and others. In recent years, the vehicle industry has also become quite interested in the research on air springs.1 or the deformation stiffness of rubber airbags2. In this study, it is concluded that the main factor influencing the stiffness of a diaphragm-type air spring is the deformation stiffness of the rubber airbag by calculating the ratio of compressed air stiffness to total stiffness. The deformation stiffness of rubber airbags is related to rubber material properties such as density, hyperelasticity viscoelasticity, and damping. All these rubber material properties should be considered in the analysis process to obtain reliable results. The analysis of the air spring consists of three different routes, namely the theoretical study, the FEA, and the experimental study. Among them, properties of rubber are involved in theory and FEA studies.Compressed air stiffness and rubber deformation stiffness make up the majority of air spring stiffness. At the moment, no consistent conclusion has been reached as to whether the main factor influencing air spring stiffness is the stiffness of compressed air3. A mechanical model of an air spring with nonlinear properties was developed based on the damping and viscoelasticity of rubber. Additionally, a six-step approach for identifying rubber parameters was suggested2.In the theoretical analysis of air spring, rubber damping, and viscoelasticity were the major factors. A study has presented a dynamic stiffness mechanical model of air springs that takes into equivalent damping and hysteresis properties in the theoretical study of air springs4. If the stiffness-proportional damping is not taken into account in the Abaqus/Explicit analysis, high-frequency oscillations will result5. The damping of the rubber support ring is used as feedback to analyze the vibration characteristics of the vehicle, and the riding comfort of the vehicle can be improved by changing the parameters related to the rubber damping6. The viscoelastic natural frequency of rubber is closer to the experiment results in the finite element modal analysis (FEMA) than the results without viscoelastic7. The viscoelasticity of materials affects the stress distribution and overall hysteresis performance of rubber in the relaxation process8. The maximum contact pressure and von Mises stress reduced in the simulation results under the rubber hyperelastic-viscoelastic constitutive model compared to the rubber hyperelastic constitutive model, while the contact width increased9.The influence of rubber damping, and viscoelasticity is also considered in the FEA of rubber products or objects with simple harmonic motion. After setting Rayleigh damping, the displacement result of simple harmonic vibration is more accurate16. In these studies, only the density and hyperelasticity are considered about rubber. Two important parameters, viscoelasticity and damping are missing.The air spring is made of rubber and primarily performs harmonic motion while working. However, the current FEA of the air spring focuses on the effect of the fabric layer arrangement, initial internal pressure, excitation, and other parameters on the stiffness of the air springThe influence of compressed air and rubber airbag deformation on the stiffness of an air spring was discussed in this paper by combining theory, FEA, and experiment. The goal of study is lowering the forward design cost. Reveal the mechanism of vertical dynamic stiffness of an air spring while. In the following text, stiffness refers to vertical stiffness.There are two types of air springs: diaphragm and bellows types. The diaphragm-type air spring was focused in this study. Through the cover plate, base, and rubber airbag, the air spring creates a pressurized air column, and then sealed by the pressure ring. Figure K is the stiffness of air spring, Ka is the stiffness of compressed air, Kr is the deformation stiffness of rubber airbag.The air spring has a better force curve than that of a metal one, as evidenced by the fact that during compression, the gas volume of the spring drops and its stiffness improves due to changes in the effective area of the compressed air column and the deformation stress on the rubber airbag. The stiffness of the air spring can be written as:Ka can be obtained by taking the derivative of load force with respect to displacement:x is the vertical displacement of the base, A is the effective area of the air spring, A with respect to the displacement, V is the volume of air spring at any height, V with respect to the displacement, P is the airbag pressure (absolute air pressure) inside, Patm is standard atmospheric pressure, P0 is the internal pressure (absolute pressure) of the air spring, V0 is the initial volume of air spring, a is the gas variability index, for adiabatic and isothermal processes a is 1.4 and 1.0, respectively.The stiffness of compressed air a = 1.0 was taken to be the input for the calculation. The effective area of a diaphragm-type air spring does not change significantly during compression and extension17. Thus, A is a constant, i.e., In the static experiment, the change of gas state in the air spring is close to the isothermal process, Therefore, According to Eq. , the stiWhere H is the overall height, F is the reaction force, V is the volume.Kr. When the stiffness nonlinearity of the air spring is not considered, the compression amount of the air spring with the same pressure corresponds to the stiffness value one by one. In practical research, it has been found that the stiffness value of the same compression amount changes with the amplitude and frequency of the excitation, that is, the dynamic stiffness changes with the variation of the excitation. In this paper, the influence of the material characteristics of rubber airbag on the dynamic stiffness of air spring and the change law of dynamic stiffness with excitation will be studied.According to the experiment data, when the air spring is compressed by 1 mm, the volume of the prototype changes to 0.0083L, which is about 0.29% of the total volume (2.84L) at the standard height. By obtaining the slope of the F–H curve, the spring stiffness was calculated to be 25N/mm and 50N/mm at the original height and the height that was compressed 40 mm, respectively. was calculated as 31.992N/mm using Eq. . The stiRubber airbag deformation stress is primarily affected by density, hyperelasticity, viscoelasticity, and damping, with density and hyperelasticity affecting static stiffness and viscoelasticity and damping affecting dynamic stiffness. This paper investigates the effect of viscoelasticity and damping on the dynamic stiffness of the air spring.E∞ running in parallel.Creep and stress relaxation are properties of viscoelastic materials. Creep is a phenomenon that occurs when a constant stress is applied to a viscoelastic sample and the strain increases with time. Stress relaxation is a phenomenon that keeps the strain constant, and the stress gradually decays with time. When dynamic loads are applied, these two properties are the primary causes of frequency dependence and hysteresis in air springs. The generalized Maxwell model is used to describe the viscoelasticity of rubber in this paper. As shown in Fig. 18:Et)( and volume modulus κt)( are expressed as follows:κt) is the storage modulus, and GL(ω) is the loss modulus.The overall relaxation modulus can be expressed asω increases, GL(ω) decreases. The energy dissipation of the rubber material is reduced, which means the stored energy is increased, the overall stiffness of the air spring is improved, that is, with the increase of the excitation angular velocity, the stiffness of the air spring will also be improved.According to Eq. , as ω inRayleigh damping is used in ABAQUS for material damping. Rayleigh damping, including mass damping and stiffness damping, is transformed by the Kelvin-Voigt model through Principle of Virtual Displacement.19:α and β are the mass and stiffness damping coefficients, respectively. M and S are the mass and stiffness damping matrices, respectively. The equivalent stress of nodes corresponding to mass damping is:Fe is the equivalent stress of the node, and The total damping matrix C can be written asAccording to Eq. , as the At low frequencies, the mass damping component bears the majority of the damping effect. The stiffness damping part is primarily responsible for the damping effect at high frequencies. Stiffness damping in Rayleigh damping reflects the blocking effect of materials on dynamic response, which is related to strain and strain rate. The contribution of strain rate to damping force is ignored in FEA, resulting in some mistakes in stress calculation. The blocking effect of the environment on rubber vibration is reflected by mass damping.ABAQUS has a rich cell library and is well-suited for analyzing highly nonlinear problems. The compressed gas sealed in the airbag is simulated as an ideal gas, and its heat exchange with the outside world during the tension and compression processes is ignored. Non-convergence in the simulation can be caused by the mechanical nonlinear characteristics of the rubber model, the setting of the rebar element used to simulate the fabric layer, the size and quality of the mesh, and other factors. In this paper, the Explicit solver was used to solve the calculation, which consumes more computational resources but was easier to converge. The airbag is connected to the cover plate and the base through a common node method. When creating a rigid body constraint, set the base and limit to a same reference point.The cover plate and base of the air spring sample used in this paper contain some gases as well, and the closed fluid cavity's composition is divided into rubber and non-rubber parts. The simulation model of the integration of airbag, cover plate, and base is established to ensure the accuracy of the airbag volume, as shown in Fig. 20 is as follows:U is the strain potential energy of rubber, I1 and I2 are the first and second partial strain variables respectively, C10 and C01 are the hyperelastic material parameters related to hardness, Je is the elastic volume ratio, and D is the volume correlation coefficient.In ABAQUS, the Mooney-Rivlin model is used to describe the hyperelasticity of rubber materials. The specific expressionC10 = 1 MPa, C01 = 0.04 MPa, and D is the volume correlation coefficient, and rubber materials are approximately incompressible, so D = 0 is taken. In ABAQUS, D = 0 indicates that the material is incompressible and will be automatically replaced with a value close to 0 during calculation. Rubber Rayleigh damping α = 0.988, β = 0.00049 can be found in the manual. Rubber viscoelastic parameters are shown in Table 121.Acrylonitrile-Butadiene Rubber is frequently used in the manufacture of air springs. The hardness is 60IRHD. According to the rubber hardness, and by comparing the static stiffness test and simulation results of the air spring, determine the hyperelastic parameters of the airbag rubber as E = 2000 MPa, Poisson's ratio μ = 0.28 and density ρ = 1.14 × 10−9 ton/mm310. See Table The fabric is made of PA66 material, with elastic modulus Simplify the air spring model. The contact nonlinearity of the air spring in this paper is mainly reflected in the air bag, the base, and the limit. Add surface to surface contact, select non airbag surface as the main contact surface, and airbag surface as the secondary contact surface. The tangential contact method is "penalty", and the friction coefficient is 0.15; The normal direction is "hard" contact, and the default constraint execution method is.−5, the molar heat capacity is 37,410, and the ambient pressure is set to 0.1 MPa. Select a point at the midpoint of the airbag on the axis of symmetry as the reference point. ABAQUS will automatically generate F3D3 (triangular shell element) and F3D4  elements with reference points and nodes of each shell element contained in the fluid cavity as vertices, as shown in Fig. The gas–solid coupling mode of the air spring is simulated by setting the fluid cavity. The surface except the limit is selected as the fluid cavity surfaces. In the experiment, nitrogen is rushed into the air bag. The molecular weight of ideal gas is set to 2.89 × 10In this simulation, one step was set for inflation analysis and ten steps for incentive analysis. The six degrees of freedom (DOF) of the cover plate and the base are constrained during the inflating step, and the air pressure is filled into the fluid cavity. To better reflect the force and changes of the airbag after inflation, a comparison diagram of the simulation model before and after inflation is compiled, as shown in Fig. a is the excitation input, A0 is the initial amplitude, A and B are the amplitudes of cosine and sine function respectively, ω is the angular velocity, t0 is the initial time.The base's movement DOF along the Y-axis is released during the excitation analysis step. Equation  depicts A0, A, t0 to 0 and B was set to 1, and the initial pressure and amplitude are fixed. Each excitation analysis step, corresponding to an excitation frequency of 1–10 Hz, the angular velocity was set to 22. The air tightness test was performed first, according to the experiment requirements, and the MTS experimental machine was chosen as the test equipment. Inflate the sample to 0.4 MPa, measure the pressure drop after 24 h, and it is qualified if it is not greater than 0.05 MPa as shown in Fig. The vertical mechanical properties of a diaphragm-type air spring were tested in accordance with Chinese national standardsThe stiffness test was performed on a sample with good air tightness. The experimental procedure is as follows: adjust the air spring to the standard height after inflation, and adjust the air pressure to 0.2 MPa, 0.4 MPa and 0.6 MPa respectively. The origin is the base position of the air spring at standard height, the cover plate is fixed, and the excitation amplitudes are 6 mm, 8 mm, 10 mm, 12 mm, 14 mm respectively, and according to the operating frequency range of the car suspension, set the test excitation frequency to 1–10 Hz, with an increment of 1 Hz. Figure After outputting the time-displacement and time-force data of the base respectively, the relationship between displacement and force is sorted out. The stiffness of the air spring under different excitation is obtained by calculating the slope of the curve. Because there are so many stiffness data, sort out the stiffness value when the air spring height under each excitation is 230 mm (enterprise standard).To sort out the simulation results in the form of curves, use frequency as the abscissa and stiffness as the ordinate, as shown in Fig. According to the change trend of the curve in Fig. To sort out the experiment results in the form of a curve, use frequency as the abscissa and stiffness as the ordinate, as shown in Fig. According to the change trend of the curve in Fig. In terms of stiffness variation trend and stiffness value, the experimental and simulation results are compared.In this paper, five groups of tests of air springs with amplitudes of 6 mm, 8 mm, 10 mm, 12 mm and 14 mm were carried out respectively. Each group of experiments is further divided into ten data sets ranging from 1 to 10HZ. To simplify the data and observe the effect of frequency on stiffness more clearly, a test group data with the amplitude of 10 mm was selected to draw a frequency stiffness curve. Figure The data in Fig. The Pearson correlation coefficient (PCCs) of calculated experimental and simulation frequency-stiffness data is shown in Table The data in Table To sort out the simulation results in the form of a curve, use amplitude as the abscissa and stiffness as the ordinate, as shown in Fig. The stiffness of the air spring decreases with increasing amplitude under three different air pressures, according to the change trend of the curves in Fig. To sort out the experiment results in the form of a curve, use amplitude as the abscissa and stiffness as the ordinate, as shown in Fig. The stiffness of the air spring decreases with increasing amplitude under three different air pressures, according to the change trend of the curves in Fig. Only the amplitude-stiffness curves of simulation and experiment are drawn here when the frequency is 5HZ to simplify the data. In addition, a clear observation of the effects of amplitudes on stiffness can be obtained, Fig. The data in Fig. The PCCs of calculated experimental and simulation amplitude-stiffness data is shown in Table The data in Table As previously stated, the stiffness of an air spring is determined by calculating the slope of the force displacement curve, which is extremely sensitive. The deformation of the airbag shell element and the fabric layer rebar element is inconsistent during the simulation process, and the damping force caused by strain rate is ignored. These factors have little effect on bearing capacity but have a greater impact on stiffness values. The results of the simulation in this paper show a strong correlation with the experimental results, demonstrating that this modeling method with integrated structure and the addition of rubber damping and viscoelastic parameters can better simulate the dynamic stiffness changes of air springs.This paper focuses on the diaphragm-type air spring and discusses the effects of rubber damping and viscoelasticity on the air spring's dynamic stiffness. By comparing the stiffness calculated using the formula to the stiffness measured in the experiment, it is determined that the stiffness of the rubber airbag is the primary cause of the air spring's nonlinear stiffness. Fourier transform of Prony series transient modulus form of generalized Maxwell model shows that with the increase of angular velocity, the loss energy decreases, the stored energy increases, and the overall stiffness of air spring increases. By analyzing the Rayleigh damping principle of mass and stiffness damping matrices, it is concluded that the larger the velocity vector of the airbag, the greater the damping force generated at the node on the airbag, the smaller the rubber deformation stress generated at the node, and the smaller the overall stiffness of the air spring. According to the national standard design air spring simulation and experimental conditions, the accuracy is verified.


Whilst contemporary literature indicates that the business environment (BE) impacts almost all entrepreneurial activities, there are indications that the unique business and institutional setting in Africa  and the nature of SMEs (their strengths and weaknesses), among other factors, lead to the context-specific impact of regulations on the performance of African SMEs. Using regressions and propensity score matching methods on a panel of 39,461 firm observations (27 African countries) from the World Bank Enterprise Surveys, we unearthed evidence to suggest that whilst enabling tax administration and business licensing regulations improve SMEs’ performance, trade facilitation impedes African SMEs’ performance. Furthermore, the institutional context of competition (from foreign firms) worsens trade facilitation’s negative impact on African SMEs’ performance. These findings suggest a fine-tuning of BE regulations in African countries. Trade facilitation, for example, must be carefully thought through and implemented in a way to benefit SMEs. Trade facilitation’s negative impact on African SMEs’ performance. This study contrasts trade facilitation’s impact on African SMEs’ performance with enabling tax administration and business registration regulations. The findings suggest that whilst enabling tax administration and business licensing regulations improve SMEs’ performance, trade facilitation impedes African SMEs’ performance. Moreover, the institutional context of competition (from foreign firms) exacerbates trade facilitation’s negative impact on African SMEs’ performance. This study’s main implications are: (1) trade facilitation and competition policies in Africa must be carefully thought through and implemented in such a way as to benefit SMEs. And (2) scholars may find useful the evidence that country-level proxies of regulations compliment consistently firm-level measures of regulations. Among the numerous developing countries, African countries have recently been of great interest to scholars and international organisations  from the World Bank Enterprise Surveys (WBES). Using panel regressions and propensity score matching (PSM) methods, our findings suggest that not all enabling BE regulations enhance African SMEs’ performance. Indeed, our findings suggest that whilst enabling tax administration and business licensing regulations improve SMEs’ performance, trade facilitation impedes African SMEs’ performance. Furthermore, we note that the institutional context of competition (from foreign firms) exacerbates trade facilitation’s negative impact on African SMEs’ performance, which is argued based on institutional weaknesses and African SMEs’ constraints.3This study makes three notable contributions to the literature on the institutional context and regulations in Africa. First, it provides first-time simultaneous evidence of the varied impact of enabling BE regulations on African SMEs’ performance. To our knowledge, no study has examined this evidence for SMEs or in the African context. Second, it provides new arguments and evidence demonstrating trade facilitation’s detrimental impact on SME performance in Africa. Third, it demonstrates that the institutional context of competition from foreign firms worsens trade facilitation’s detrimental impact on SMEs’ performance. In addition, by proxying regulations with objective country-level and subjective firm-level indicators, we provide a more thorough analysis of their impact and complementarity concerning firm performance.The rest of this paper is structured as follows: Sect. 2 presents our theoretical arguments and hypotheses, whilst Sect. 3 clarifies the data and empirical methods we employed for our study. Section 4 then reveals the results and presents the discussion. Finally, Sect. 5 concludes the paper.Policymakers and scholars have recently taken great interest in African countries because Africa presents a unique and challenging context for entrepreneurship African countries undoubtedly struggle with providing institutions to support their markets  exacerbates (or moderates negatively) trade facilitation’s negative impact on African SMEs’ performance.As posited hitherto, African SMEs are embedded in a context with specific features and limitations that impact their operations. Additionally, SMEs have limited resources and managerial capacity that limit the positive impact of trade participation. For instance, African SMEs face greater challenges in accessing finance than large firms  are not included in the EODB score  has been calculated using at least two different methodologies since 2002. Based on availability and practicality, scores based on the 2006–2015 methodology for the ease-of-trading-across-borders, the 2004–2020 methodology for the ease-of-starting-a-business, and the 2006–2016 methodology for the ease-of-paying-taxeTable Some of the standard measures of SME performance used in the literature are revenue, growth, profit, return on assets, return on investment, return on equity, and Tobin’s Q. We select revenue  as the measure of SMEs’ performance following similar studies  Doing Business scores from the World Bank following similar studies Bosire, . These pFurthermore, relevant regulations in this study are proxied by three subjective firm-level measures/variables (in the WBES sample) that cover the perceived impact of business regulations on SMEs following similar studies  is proxied by the highly comprehensive KOF GlobalisationThe KOF Globalisation Index is widely used in economics to measure globalisation, competition, institutional context or quality, and the development of countries  and firm-level subjective regulations . Controls refers to a set of controls, including the firm’s sourcing from retained earnings and bank finance; access to finance; the firm’s size, age, and legal status; the human capital of the firm’s owner or manager; competition from informal firms; corruption; and the GDP per capita of the country where the firm operates. V refers to unobserved idiosyncratic errors. We first used the panel regression estimator for our initial econometric analysis following similar studies  error term (or omitted variable) is correlated with the regressors, which confounds the estimations  referred to scores above the 50th percentile in each distribution. Furthermore, we constructed additional treatment variables from the responses of the three subjective firm-level regulatory BE variables as follows: an obstructive regulatory BE (coded 0) referred to responses from firms that considered a specific regulation a ‘major obstacle’ or ‘severe obstacle’ to their operations, whilst an enabling regulatory BE (coded 1) referred to responses from firms that considered a specific regulation a ‘no obstacle’ or a ‘minor obstacle’ to their operations.As treatment variables that correspond to the explanatory (independent) variables are needed to perform PSM analyses, we constructed three treatment variables from the distribution of the three objective (country-level) Doing Business scores  into a single propensity score, calculated as the probability of treatment on the covariates. After propensity scores are obtained, individual firms with similar propensity scores can be compared (matched) across the control group (obstructive regulatory BE) and the treated group (enabling regulatory BE). Because propensity scores are estimated with a logit (or probit) model, our logit regression was formulated as follows.T is the binary treatment variable representing whether a firm is located in an obstructive (= 0) or enabling (= 1) regulatory BE, i refers to each firm in the sample, Z refers to the matching criteria or covariates used in this study, and v refers to the unobserved error.Here, The propensity scores, once computed, formed the basis for matching firms across the control and treated groups. We utilised these matching approaches to ensure consistency , 52.64% are small firms (5–19 employees), 28.26% are medium firms (20–99 employees), and 14.04% are large firms (100–250 employees). Moreover, 53.55% of firms are limited partnerships, whilst only 19.84% are ordinary partnerships and 5.16% are sole proprietorships. These statistics indicate an improvement in the general size and legal structure of registered firms in Africa  provide adequate support for this prediction, which means that, holding all other factors fixed, a one-unit increase in trade facilitation (proxied by the ease-of-trading-across-borders objective country-level measure) results in a 4% decrease in SMEs’ revenue. In addition, holding all other factors fixed, a one-unit increase in trade facilitation (proxied by subjective firm-level customs and trade regulations) results in an 11.9% decrease in revenue for SMEs. The ATET results of all PSM methods are statistically identical  predicted that trade facilitation has a negative impact on African SMEs’ performance. The panel regression results (see Model 2 of Table p < 0.01). Figure The second hypothesis H2) predicted that the institutional context of competition (from foreign firms) exacerbates (or moderates negatively) trade facilitation’s negative impact on African SMEs’ performance. Model 3 of Table  predicteFurthermore, despite trade facilitation’s negative impact on SMEs’ performance, the panel regression estimator results and the ATET results of all PSM methods, confirm the positive impact of enabling tax administration and business licencing and registration regulations on SMEs’ performance  and subjective (firm-level) proxies of regulations, our findings confirm the hypotheses of this study, that is, the negative impact of trade facilitation as opposed to the positive impact of tax administration and business licencing regulations on African SMEs’ performance (Adeniyi & Imade, An alternative measure of performance, profit, was used for the econometric analyses to confirm the results’ robustness. All results obtained from these robustness checks were statistically the same as those in the main analyses (see Appendix Tables This study aimed to extend the research on institutional context and BE regulations’ impact on African SMEs’ performance. Whilst enabling tax administration and business licensing and registration regulations improve African firms’ operations and performance (Adeniyi & Imade, Using regressions and PSM methods on the latest cross-country African panel datasets from the WBES, our findings interestingly indicate that, whilst enabling tax administration and business licensing regulations improve SMEs’ performance, trade facilitation impedes African SMEs’ performance. Furthermore, we note that the institutional context of competition exacerbates trade facilitation’s negative impact on African SMEs’ performance.These findings are interesting since they show that not all enabling regulations promoted in policies directed at SMEs in Africa and perhaps other developing countries benefit SMEs. SMEs have unique challenges and are unable to compete with foreign firms when trade across borders is liberalised in African countries. In such instances, trade facilitation counteracts its intended purpose of improving SMEs’ performance (Hunt et al., This study makes three important contributions to the literature on institutional heterogeneity in Africa: First, it provides first-time simultaneous evidence of the varied impact of enabling BE regulations on African SMEs’ performance. To our knowledge, no study has examined such evidence regarding Africa. Second, this study offers new evidence demonstrating trade facilitation’s detrimental impact on African SMEs’ performance, which should be insightful to policymakers. Third, this study provides evidence that the institutional context of competition worsens trade facilitation’s detrimental impact on SMEs’ performance. Additionally, this study provides new evidence on the complementarity of objective country-level and subjective firm-level measures of regulations.This study’s findings should interest policymakers, governments, and scholars, especially in Africa, since they present certain implications. First, these findings call for a recalibration of some regulatory policies. We suggest that initiatives to improve the regulatory framework in African countries be fine-tuned to benefit SMEs. For example, whilst the provision of an adequate business licensing and registration system greatly increases formality and improves firms’ performance (Alfaro & Chari, Our study was limited by the sample of African countries used; conducting a similar study focused on other developing countries from other regions or emerging economies would therefore be insightful. It would also be insightful to conduct a study that compares the impact of BE regulations in developing countries with those in developed countries.


Intra articular length (IAL) of the graft has not been measured yet in anatomic, single bundle, anterior cruciate ligament (ACL) reconstruction. Especially in the all-inside ACL reconstruction technique, the IAL of the graft is of great importance due to the philosophy of the technique and the risk of graft “bottoming out”. We present a simple arthroscopic measurement of the IAL of the ACL graft in anatomic, single bundle ACL reconstruction, that will allow optimal application of the all-inside technique. The main characteristics of the all-inside anterior cruciate ligament (ACL) reconstruction technique are the use of short grafts and the constructions of sockets, as opposed to full-length tunnels. Historically, it was Morgan et al.  that desThe most important risk of this technique is the graft-tunnel mismatch that would lead to inadequate graft tension and as a result to a loose graft. In detail, if the graft length is not less than the sum of femoral socket length plus intra-articular graft distance plus tibia socket length, then “bottoming-out” of the graft will take place and the clinical result of the ACL reconstruction may be compromised ,3.As a result, the intra articular length (IAL) of the graft is of great importance for an optimal all-inside ACL reconstruction. Nevertheless, IAL measurement of the graft in anatomic, single bundle ACL reconstruction has not been reported yet. Lubowitz  proposedThe purpose of this technical report is to present a simple arthroscopic measurement of the IAL of the ACL graft in anatomic, single bundle ACL reconstruction.The femoral socket is drilled with the outside-in technique with the knee flexed at 90°. The anteromedial portal serves as the viewing portal and the outside-in guide is placed in the femoral footprint of the ACL through the anterolateral portal. Once the femoral socket has been constructed with the outside-in technique, a shuttle suture is advanced into the joint with the aid of a pin with an eyelet, that will later help in graft passage. The shuttle suture has been previously marked to serve as a ruler. In detail, the center of the length of the suture is marked with a marking pen. This mark will be the zero-point. Additional marks are then made at a distance of 20, 25 and 30 mm Figure .The marked shuttle suture is grasped with a KingFisher grasper  from the zero-point mark Figure .The shuttle suture is then brought to the center of the ACL tibia footprint, put under slight tension, in order not to be loose, and the guide pin is moved backwards so that the base of the eyelet is flush with the level of the femoral socket entrance Figure .Since the guide pin is in the center of the femoral socket, the shuttle suture that rests at the base of the guide pin eyelet is positioned in the center of the femoral ACL footprint.The length of the shuttle suture at this point represents the intra-articular distance of the ACL graft. The surgeon reads the 20, 25 and 30 mm marks on the shuttle suture and has a gross IAL graft measurement at 90° of knee flexion.Our technique Figure  is the fIAL graft measurement is very important in the all-inside ACL reconstruction technique. The length of the graft (GL) after tensioning Figure , has to In case of underestimation (IAL of the graft more than estimated), the graft cannot be tensioned because of “bottoming-out” and the graft remain loose Figures , 7.In this scenario, the surgeon should remove the graft and recreate the sockets, increasing their length. This is a difficult task to accomplish, and it may necessitate removal of the hardware used for graft fixation (buttons) and utilization of new hardware. As a result, graft bottoming out needs additional surgical time and risk and may necessitate increased surgical exposure and cost.In case of overestimation (IAL of the graft less than estimated), the surgeon will drill longer than needed sockets. Such a scenario could make non-applicable the use of the all-inside ACL reconstruction technique in small knees, where small in-length sockets are needed to accomplish the technique. Especially in paediatric ACL reconstruction, where full epiphyseal sockets are mandatory in order to avoid growth disturbance, the length of the sockets has an upper limit, determined by the growth plate Figure .Moreover, the utilization of sockets offers the advantage of tunnel enlargement prevention and graft maturation acceleration, due to the dead space eradication . As a reThe length of the ACL has been found to be influenced by patient’s sex and height and has a wide range of 20 mm (22 to 41 mm) ,7. This Our technique measures the IAL of the graft at 90° of knee flexion. We have, though, to underline that anatomic, single bundle ACL reconstruction results in different IAL of the graft at 90° and full knee extension. Yoo et al.  used a tAnother limitation of our technique is the fact that it gives only a gross measurement of the IAL of the graft. The marking of the shuttle suture cannot indicate values of one mm accuracy since the ink is absorbed by the suture. Nevertheless, the surgeon can easily recognize whether the IAL graft is 20 mm, or near 20 etc. In our opinion the construction of a calibrated shuttle suture would overcome this limitation and our technique would give an accurate result.In conclusion, intra articular graft length measurement is of great importance in all-inside ACL reconstruction, since it determines the length of the sockets. Short sockets may lead to graft bottoming out while long sockets eliminate the advantages of the all-inside technique or make it non-applicable. Our technique of intra articular graft length measurement is currently the only accurate and anatomic available technique.