The effect of fecal microbiota transplantation on antibiotic-associated diarrhea and its impact on gut microbiota.

BACKGROUND: Antibiotic-associated diarrhea (AAD) refers to symptoms of diarrhea that cannot be explained by other causes after the use of antibiotics. AAD is thought to be caused by a disruption of intestinal ecology due to antibiotics. Fecal Microbiota Transplantation (FMT) is a treatment method that involves transferring microbial communities from the feces of healthy individuals into the patient's gut. METHOD: We selected 23 AAD patients who received FMT treatment in our department. Before FMT, we documented patients' bowel movement frequency, abdominal symptoms, routine blood tests, and inflammatory markers, and collected fecal samples for 16S rRNA sequencing to observe changes in the intestinal microbiota. Patients' treatment outcomes were followed up 1 month and 3 months after FMT. RESULTS: Out of the 23 AAD patients, 19 showed a clinical response to FMT with alleviation of abdominal symptoms. Among them, 82.61% (19/23) experienced relief from diarrhea, 65% (13/20) from abdominal pain, 77.78% (14/18) from abdominal distension, and 57.14% (4/7) from bloody stools within 1 month after FMT. Inflammatory markers IL-8 and CRP significantly decreased after FMT, but there were no noticeable changes in WBC, IL-6, and TNF-α before and after transplantation. After FMT, the abundance of Bacteroides and Faecalibacterium increased in patients' fecal samples, while the abundance of Escherichia-Shigella and Veillonella decreased. CONCLUSION: FMT has a certain therapeutic effect on AAD, and can alleviate abdominal symptoms and change the intestinal microbiota of patients.

Donor-recipient intermicrobial interactions impact transfer of subspecies and fecal microbiota transplantation outcome.

Studies on fecal microbiota transplantation (FMT) have reported inconsistent connections between clinical outcomes and donor strain engraftment. Analyses of subspecies-level crosstalk and its influences on lineage transfer in metagenomic FMT datasets have proved challenging, as single-nucleotide polymorphisms (SNPs) are generally not linked and are often absent. Here, we utilized species genome bin (SGB), which employs co-abundance binning, to investigate subspecies-level microbiome dynamics in patients with autism spectrum disorder (ASD) who had gastrointestinal comorbidities and underwent encapsulated FMT (Chinese Clinical Trial: 2100043906). We found that interactions between donor and recipient microbes, which were overwhelmingly phylogenetically divergent, were important for subspecies transfer and positive clinical outcomes. Additionally, a donor-recipient SGB match was indicative of a high likelihood of strain transfer. Importantly, these ecodynamics were shared across FMT datasets encompassing multiple diseases. Collectively, these findings provide detailed insight into specific microbial interactions and dynamics that determine FMT success.

Regional homogeneity alterations in patients with functional constipation and their associations with gene expression profiles.

Functional constipation, a highly prevalent functional gastrointestinal disorder, often accompanies by mental and psychological disorders. Previous neuroimaging studies have demonstrated brain functional and structural alterations in patients with functional constipation. However, little is known about whether and how regional homogeneity is altered in these patients. Moreover, the potential genetic mechanisms associated with these alterations remain largely unknown. The study included 73 patients with functional constipation and 68 healthy controls, and regional homogeneity comparison was conducted to identify the abnormal spontaneous brain activities in patients with functional constipation. Using Allen Human Brain Atlas, we further investigated gene expression profiles associated with regional homogeneity alterations in functional constipation patients with partial least squares regression analysis applied. Compared with healthy controls, functional constipation patients demonstrated significantly decreased regional homogeneity in both bilateral caudate nucleus, putamen, anterior insula, thalamus and right middle cingulate cortex, supplementary motor area, and increased regional homogeneity in the bilateral orbitofrontal cortex. Genes related to synaptic signaling, central nervous system development, fatty acid metabolism, and immunity were spatially correlated with abnormal regional homogeneity patterns. Our findings showed significant regional homogeneity alterations in functional constipation patients, and the changes may be caused by complex polygenetic and poly-pathway mechanisms, which provides a new perspective on functional constipation's pathophysiology.

Facile Electrochemical Synthesis of Bifunctional Needle-like Co-P Nanoarray for Efficient Overall Water Splitting.

The development of low-cost and high-performance bifunctional electrocatalysts for overall water splitting is still challenging. Herein, we employed a facile electrodeposition method to prepare bifunctional cobalt phosphide for overall water splitting. The needle-like cobalt phosphide (Co-P-1) nanoarray is uniformly distributed on nickel foam. Co-P-1 exhibits excellent electrocatalytic activity for hydrogen evolution reaction (HER, 85 mV at 10 mA/cm2, 60 mV/dec) and oxygen evolution reaction (OER, 294 mV at 50 mA/cm2, 60 mV/dec). The cell-voltage of 1.60 V is found to achieve the current density of 10 mA/cm2 for overall water splitting in the two-electrode system, comparable to that of previously reported Pt/C/NF||RuO2/NF. The excellent electrocatalytic performance can be attributed to the needle-like structure with more active sites, accelerated charge transfer and evolved bubbles' release. This work can provide new approach to the development of a bifunctional electrocatalyst for overall water splitting.

Depletion of butyrate-producing microbes of the Firmicutes predicts nonresponse to FMT therapy in patients with recurrent Clostridium difficile infection.

Approximately 10% of individuals diagnosed with Clostridium difficile infection (CDI) show the resistance to fecal microbiota transplantation (FMT), with the underlying mechanisms remaining elusive. Deciphering the intricate microbiome profile within this particular subset of FMT-refractory patients via clinical FMT investigations assumes paramount importance, as it holds the key to designing targeted therapeutic interventions tailored for CDI, particularly recurrent CDI (rCDI). A cohort of twenty-three patients afflicted with rCDI, exhibiting congruent clinical baselines, was meticulously selected for FMT. Rigorous screening of thousands of healthy individuals identified ten FMT donors who met stringent health standards, while a total of 171 stool samples were collected to serve as healthy controls. To assess the influence of microbiome dynamics on FMT efficacy, fecal samples were collected from four donors over a continuous period of twenty-five weeks. After FMT treatment, seven individuals exhibited an inadequate response to FMT. These non-remission patients displayed a significant reduction in α-diversity indexes. Meanwhile, prior to FMT, the abundance of key butyrate-producing Firmicutes bacteria, including Christensenellaceae_R_7_group, Ruminococcaceae_unclassified, Coprococcus_2, Fusicatenibacter, Oscillospira, and Roseburia, were depleted in non-remission patients. Moreover, Burkholderiales_unclassified, Coprococcus_2, and Oscillospira failed to colonize non-remission patients both pre- and post-treatment. Conversely, patients with a favorable FMT response exhibited a higher relative abundance of Veillonella prior to treatment, whereas its depletion was commonly observed in non-remission individuals. Genera interactions in lower effectiveness FMT donors were more similar to those in non-remission patients, and Burkholderiales_unclassified, Coprococcus_2, and Oscillospira were frequently depleted in these lower effectiveness donors. Older patients were not conducive to the colonization of Veillonella, consistent with their poor prognosis after FMT. FMT non-remission rCDI patients exhibited distinct characteristics that hindered the colonization of beneficial butyrate-producing Firmicutes microbes. These findings hold promise in advancing the precision of FMT therapy for rCDI patients.

An R2R3 MYB transcription factor PsFLP regulates the symmetric division of guard mother cells during stomatal development in Pisum sativum.

MYB transcriptional regulators belong to one of the most significant transcription factors families in plants, among which R2R3-MYB transcription factors are involved in plant growth and development, hormone signal transduction, and stress response. Two R2R3-MYB transcription factors, FLP and its paralogous AtMYB88, redundantly regulate the symmetrical division of guard mother cells (GMCs), and abiotic stress response in Arabidopsis thaliana. Only one orthologue gene of FLP was identified in pea (Pisum sativum FLP; PsFLP). In this study, we explored the gene function of PsFLP by virus-induced gene silencing (VIGS) technology. The phenotypic analysis displayed that the silencing of PsFLP expression led to the abnormal development of stomata and the emergence of multiple guard cells tightly united. In addition, the abnormal stomata of flp could be fully rescued by PsFLP driven by the FLP promoter. In conclusion, the results showed that PsFLP plays a conservative negative role in regulating the symmetric division of GMC during stomatal development. Based on real-time quantitative PCR, the relative expressions of AAO3, NCED3, and SnRK2.3 significantly increased in the flp pFLP::PsFLP plants compared to mutant, indicating that PsFLP might be involved in drought stress response. Thus, PsFLP regulates the genes related to cell cycle division during the stomatal development of peas and participates in response to drought stress. The study provides a basis for further research on its function and application in leguminous crop breeding.

Improved methane production of two-phase anaerobic digestion by cobalt: Efficiency and mechanism.

Two-phase anaerobic digestion (AD) is a promising technology, but its performance is sensitive to methanogen. In this study, the effect of cobalt (Co) on two-phase AD was investigated and the enhanced mechanism was revealed. Though no obvious effect of Co2+ was observed in acidogenic phase, the activity of methanogens was significantly affected by Co2+ with an optimal Co2+ concentration of 2.0 mg/L. Ethylenediamine-N'-disuccinic acid (EDDS) was the most effective for improving Co bioavailability and increasing methane production. The role of Co-EDDS in improving methanogenic phase was also verified by operating three reactors for two months. The Co-EDDS supplement increased the level of Vitamin B12 (VB12) and coenzyme F420, and enriched Methanofollis and Methanosarcina, thereby successfully improving methane production and accelerating reactor recovery from ammonium and acid wastewater treatment. This study provides a promising approach to improve the efficiency and stability of anaerobic digester.

Whole intestinal microbiota transplantation is more effective than fecal microbiota transplantation in reducing the susceptibility of DSS-induced germ-free mice colitis.

Fecal microbiota transplantation (FMT) is an emerging and effective therapy for the treatment of inflammatory bowel disease (IBD). Previous studies have reported that compared with FMT, whole intestinal microbiota transplantation (WIMT) can more precisely replicate the community structure and reduce the inflammatory response of the host. However, it remains unclear whether WIMT is more effective in alleviating IBD. To examine the efficacy of WIMT and FMT in the intervention of IBD, GF (Germ-free) BALB/c mice were pre-colonized with whole intestinal microbiota or fecal microbiota before being treated with dextran sodium sulfate (DSS). As expected, the symptoms of colitis were alleviated by both WIMT and FMT, as demonstrated by the prevention of body weight loss and decreased the Disease activity index and histological scores in mice. However, WIMT's anti-inflammatory effect was superior to that of FMT. In addition, the inflammatory markers myeloperoxidase (MPO) and eosinophil peroxidase were dramatically downregulated by WIMT and FMT. Furthermore, the use of two different types of donors facilitated the regulation of cytokine homeostasis in colitis mice; the level of the pro-inflammatory cytokine IL-1ß in the WIMT group was significantly lower than that in the FMT group, while the level of the anti-inflammatory factor IL-10 was significantly higher than that in the FMT group. Both groups showed enhanced expression of occludin to protect the intestinal barrier in comparison with the DSS group, and the WIMT group demonstrated considerably increased levels of ZO-1. The sequencing results showed that the WIMT group was highly enriched in Bifidobacterium, whereas the FMT group was significantly enriched in Lactobacillus and Ochrobactrum. Correlation analysis revealed that Bifidobacterium was negatively correlated with TNF-α, whereas Ochrobactrum was positively correlated with MPO and negatively correlated with IL-10, which might be related to different efficacies. Functional prediction using PICRUSt2 revealed that the FMT group was considerably enriched in the L-arginine biosynthesis I and L-arginine biosynthesis IV pathway, whereas the WIMT group was enriched in the L-lysine fermentation to acetate and butanoate pathway. In conclusion, the symptoms of colitis were subsided to varying degrees by the two different types of donors, with the WIMT group being more effective than the FMT group. This study provides new information on clinical interventions for IBD.

Fecal microbiota transplantation improves VPA-induced ASD mice by modulating the serotonergic and glutamatergic synapse signaling pathways.

Autism spectrum disorder (ASD) is a complex behavioral disorder diagnosed by social interaction difficulties, restricted verbal communication, and repetitive behaviors. Fecal microbiota transplantation (FMT) is a safe and efficient strategy to adjust gut microbiota dysbiosis and improve ASD-related behavioral symptoms, but its regulatory mechanism is unknown. The impact of the microbiota and its functions on ASD development is urgently being investigated to develop new therapeutic strategies for ASD. We reconstituted the gut microbiota of a valproic acid (VPA)-induced autism mouse model through FMT and found that ASD is in part driven by specific gut dysbiosis and metabolite changes that are involved in the signaling of serotonergic synapse and glutamatergic synapse pathways, which might be associated with behavioral changes. Further analysis of the microbiota showed a profound decrease in the genera Bacteroides and Odoribacter, both of which likely contributed to the regulation of serotonergic and glutamatergic synapse metabolism in mice. The engraftment of Turicibacter and Alistipes was also positively correlated with the improvement in behavior after FMT. Our results suggested that successful transfer of the gut microbiota from healthy donors to ASD mice was sufficient to improve ASD-related behaviors. Modulation of gut dysbiosis by FMT could be an effective approach to improve ASD-related behaviors in patients.

Protective effect of α7 nicotinic acetylcholine receptor activation on experimental colitis and its mechanism.

BACKGROUND: Inflammatory bowel disease (IBD) is a common chronic remitting disease with no satisfactory treatment. The aim of this study was to investigate the protective effect of α7 nicotinic acetylcholine receptor (α7nAChR), and to determine the underlying mechanism of its activity. METHODS: The expression and distribution of α7nAChR in the intestinal tissue of patients with ulcerative colitis and Crohn's disease were analyzed. The effects of vagal excitation on murine experimental colitis were investigated. The colitis model was induced in C57BL/6 mice by the administration of 3% dextran sulfate sodium (DSS). The therapeutic group received treatment with the α7nAChR agonist PNU-282987 by intraperitoneal injection. RESULTS: Our results showed that there was significantly increased expression of α7nAChR in colitis and Crohn's disease intestinal tissue, and its expression was mainly located in macrophages and neutrophils, which were extensively infiltrated in the disease status. Treatment with an α7nAChR agonist potently ameliorated the DSS-induced illness state, including weight loss, stool consistency, bleeding, colon shortening, and colon histological injury. α7nAChR agonist exerted anti-inflammatory effects in DSS colitis mice by suppressing the secretion of multiple types of proinflammatory factors, such as IL6, TNFα, and IL1ß, and it also inhibited the colonic infiltration of inflammatory cells by blocking the DSS-induced overactivation of the NF-κB and MAPK signaling pathways. Mechanistically, activation of α7nAChR decreased the number of infiltrated M1 macrophages in the colitis intestine and inhibited the phagocytosis ability of macrophages, which were activated in response to LPS stimulation. CONCLUSION: Thus, an α7nAChR agonist ameliorated colonic pathology and inflammation in DSS-induced colitis mice by blocking the activation of inflammatory M1 macrophages.

Involvement of VIVID in white light-responsive pigmentation, sexual development and sterigmatocystin biosynthesis in the filamentous fungus Podospora anserina.

Light serves as a source of information and regulates diverse physiological processes in living organisms. Fungi perceive and respond to light through a complex photosensory system. Fungi have evolved the desensitization mechanism to adapt to the changing light signal in a natural environment. White light exerts multiple essential impacts on the model filamentous fungus Podospora anserina. However, the light sensing and response in this species has not been investigated. In this study, we demonstrated that the loss of function of the light desensitization protein VIVID (VVD) in P. anserina triggered exacerbated light responses and therefore led to drastic morphological and physiological changes. The white light-sensitive mutant Δvvd showed growth reduction, spermatia overproduction, enhanced hyphae pigmentation and reduced oxidative stress tolerance. We observed the decreased expression level of sterigmatocystin gene cluster by transcriptome analysis and finally detected the reduced production of sterigmatocystin in Δvvd in response to white light. Our data indicate that VVD acts as a repressor of white collar complex. This study exhibits a vital role of VVD in governing white light-responsive gene expression and secondary metabolite production and contributes to a better understanding of the photoreceptor VVD in P. anserina.

Extracellular vesicle-mediated communication between hepatocytes and natural killer cells promotes hepatocellular tumorigenesis.

Hepatocellular carcinoma (HCC) is frequently characterized by metabolic and immune remodeling in the tumor microenvironment. We previously discovered that liver-specific deletion of fructose-1, 6-bisphosphatase 1 (FBP1), a gluconeogenic enzyme ubiquitously suppressed in HCC tissues, promotes liver tumorigenesis and induces metabolic and immune perturbations closely resembling human HCC. However, the underlying mechanisms remain incompletely understood. Here, we reported that FBP1-deficient livers exhibit diminished amounts of natural killer (NK) cells and accelerated tumorigenesis. Using the diethylnitrosamine-induced HCC mouse model, we analyzed potential changes in the immune cell populations purified from control and FBP1-depleted livers and found that NK cells were strongly suppressed. Mechanistically, FBP1 attenuation in hepatocytes derepresses an zeste homolog 2 (EZH2)-dependent transcriptional program to inhibit PKLR expression. This leads to reduced levels of PKLR cargo proteins sorted into hepatocyte-derived extracellular vesicles (EVs), dampened activity of EV-targeted NK cells, and accelerated liver tumorigenesis. Our study demonstrated that hepatic FBP1 depletion promotes HCC-associated immune remodeling, partly through the transfer of hepatocyte-secreted, PKLR-attenuated EVs to NK cells.

Enteral nutrition ameliorates the symptoms of Crohn's disease in mice via activating special pro-resolving mediators through innate lymphoid cells.

Crohn's disease activates the inflammatory reactions to induce intestinal disorders. Enteral nutrition (EN) could exert general immunomodulatory effects. Cecal ligation and perforation (CLP) surgery was utilized to establish Crohn's disease mice models. Survival analysis, hematoxylin-eosin staining, flow cytometry, ELISA, Western blot and liquid chromatography-tandem MS were applied. Baicalein was added to inhibit lipoxygenases. The survival rate was restored and inflammatory injury, exudate neutrophils in peritoneal lavage and serum levels of IL-6 and TNF-α were ameliorated by EN treatment as compared with CLP treatment. EN also increased ILC-3 content, 5/15-LOX level and RvD1-RvD5 in peritoneal lavage. Baicalein reversed all the detected effects of EN except ILC-3 content. EN could activate special pro-resolving mediators (SPMs) through ILCs to mitigate injuries of Crohn's disease.

The Efficacy and Safety of Fecal Microbiota Transplantation Combined With Biofeedback for Mixed Constipation: A Retrospective Cohort Study.

This study aims to assess the effectiveness and safety of fecal microbiota transplantation (FMT) combined with biofeedback for patients with mixed constipation. Patients who received biofeedback (biofeedback group, n = 40) and those who received FMT combined with biofeedback (FMT combination group, n = 45) were enrolled. Spontaneous bowel movements (SBMs) frequency, Bristol Stool Form Scale (BSFS), and Patient Assessment of Constipation Symptoms (PAC-SYM) score were analyzed to evaluate the effect of treatment. Gastrointestinal Quality of Life Index (GIQLI) scores of patients were used to assess the quality of life, and the safety of FMT combination therapy was evaluated by the presence of adverse events. The 16S rRNA gene sequencing was performed on the fecal samples of 12 donors, feces of 31 patients before and after receiving FMT combination treatment. Comparing the biofeedback group and the FMT combination group 1 month after the treatment, significant differences were observed in the mean value of SBM frequency, BSFS, and PAC-SYM scores, which were 2.15 ± 1.05 vs. 3.61 ± 0.89 (p = 0.0031), 2.1 ± 0.9 vs. 2.5 ± 1.2 (p = 0.008), and 2.4 ± 0.5 vs. 2.2 ± 0.6 (p = 0.0021), respectively. Meanwhile, FMT combination therapy had long-term beneficial effects according to the data collected at six months and 12 months after the treatment. With respect to the quality of life, GIQLI scores were higher in the FMT combination group (103.6 ± 15.1) compared with that in the biofeedback group (88.7 ± 10.1) one month after administration (p = 0.0042). In addition, there were no significant differences between the two groups in adverse events, including abdominal pain, diarrhea, dizziness, nausea, vomiting, and other side effects. Results of 16S rRNA gene sequencing showing some well-known probiotics had significantly increased after FMT combination treatment compared with pre-FMT samples, such as Prevotella and Bifidobacterium. Findings of this study suggested that FMT combined with biofeedback could be effective and safe for patients with mixed constipation.

Fecal Microbiota Transplantation Modulates the Gut Flora Favoring Patients With Functional Constipation.

Intestinal dysmotility is common in many diseases and is correlated with gut microbiota dysbiosis and systemic inflammation. Functional constipation (FC) is the most typical manifestation of intestinal hypomotility and reduces patients' quality of life. Some studies have reported that fecal micriobiota transplantation (FMT) may be an effective and safe therapy for FC as it corrects intestinal dysbiosis. This study was conducted to evaluate how FMT remodels the gut microbiome and to determine a possible correlation between certain microbes and clinical symptoms in constipated individuals. Data were retrospectively collected on 18 patients who underwent FMT between January 1, 2019 and June 30, 2020. The fecal bacterial genome was detected by sequencing the V3-V4 hypervariable regions of the 16S rDNA gene. Fecal short chain fatty acids (SCFAs) were detected by gas chromatography-mass spectrometry, and serum inflammatory factor concentrations were detected via enzyme-linked immunosorbent assay. Comparing the changes in fecal microbiome compositions before and after FMT revealed a significant augmentation in the alpha diversity and increased abundances of some flora such as Clostridiales, Fusicatenibacter, and Paraprevotella. This was consistent with the patients experiencing relief from their clinical symptoms. Abundances of other flora, including Lachnoanaerobaculum, were decreased, which might correlate with the severity of patients' constipation. Although no differences were found in SCFA production, the butyric acid concentration was correlated with both bacterial alterations and clinical symptoms. Serum IL-8 levels were significantly lower after FMT than at baseline, but IL-4, IL-6, IL-10, and IL-12p70 levels were not noticeably changed. This study showed how FMT regulates the intestinal microenvironment and affects systemic inflammation in constipated patients, providing direction for further research on the mechanisms of FMT. It also revealed potential microbial targets for precise intervention, which may bring new breakthroughs in treating constipation.

Long-Term Follow-Up Results of Fecal Microbiota Transplantation for Irritable Bowel Syndrome: A Single-Center, Retrospective Study.

Objective: This study aimed to investigate the long-term efficacy of fecal microbiota transplantation (FMT) in patients with irritable bowel syndrome (IBS). Study Methods: In this single-center long-term follow-up study, FMT treatment was administered to patients with moderate to severe IBS (IBS severity scoring system (IBS-SSS) > 175). After 1 year of treatment, it was decided whether to repeat FMT based on IBS-SSS score (IBS-SSS > 175). Baseline characteristics before and after FMT and questionnaires were completed at 1, 3, 6, 12, 24, 36, 48, and 60 months after FMT. The study outcomes included treatment efficacy rates, change of IBS-SSS, IBS-specific quality of life and fatigue, effect on stool frequency, Bristol Stool Scale for IBS-C and IBS-D, and side effects. Results: A total of 227 patients (47.58% IBS-C, 39.21% IBS-D, and 13.22% IBS-M) were recruited (142 females and 85 males with a mean age of 41.89 ± 13.57 years). The efficacy rates were 108 (51.92%), 147 (74.62%), 125 (74.41 %), 88 (71.54%), 78 (75.00%), 65 (73.03%), 45 (61.64%), and 37 (62.71%) at different follow-up time points. The total IBS-SSS score was 321.37 ± 73.89 before FMT, which significantly decreased after 1 month. The IBS-specific quality of life (IBS-QoL) score was 40.24 ± 11.34 before FMT, increased gradually, and was significantly higher at 3 months compared to before FMT. The total Fatigue Assessment Scale (FAS) score was 47 ± 8.64 before FMT and was significantly lower at 3 months. During follow-up, 89 (39.21%) side effects occurred that were alleviated by symptomatic treatment, and no serious adverse events were detected. Conclusion: Based on 60 months of long-term follow-up, the safety and efficacy of FMT for IBS was established. However, as the treatment effect declines over time, periodic and repetitive FMT is required for a sustained effect.

Characterize traction-separation relation and interfacial imperfections by data-driven machine learning models.

Interfacial mechanical properties are important in composite materials and their applications, including vehicle structures, soft robotics, and aerospace. Determination of traction-separation (T-S) relations at interfaces in composites can lead to evaluations of structural reliability, mechanical robustness, and failures criteria. Accurate measurements on T-S relations remain challenging, since the interface interaction generally happens at microscale. With the emergence of machine learning (ML), data-driven model becomes an efficient method to predict the interfacial behaviors of composite materials and establish their mechanical models. Here, we combine ML, finite element analysis (FEA), and empirical experiments to develop data-driven models that characterize interfacial mechanical properties precisely. Specifically, eXtreme Gradient Boosting (XGBoost) multi-output regressions and classifier models are harnessed to investigate T-S relations and identify the imperfection locations at interface, respectively. The ML models are trained by macroscale force-displacement curves, which can be obtained from FEA and standard mechanical tests. The results show accurate predictions of T-S relations (R2 = 0.988) and identification of imperfection locations with 81% accuracy. Our models are experimentally validated by 3D printed double cantilever beam specimens from different materials. Furthermore, we provide a code package containing trained ML models, allowing other researchers to establish T-S relations for different material interfaces.

3D printing of biomedically relevant polymer materials and biocompatibility.

ABSTRACT: Research on polymer materials for additive manufacturing technology in biomedical applications is as promising as it is numerous, but biocompatibility of printable materials still remains a big challenge. Changes occurring during the 3D-printing processes itself may have adverse effects on the compatibility of the completed print. This prospective will put emphasis on the different additives and processes that can have a direct impact on biocompatibility during and after 3D printing of polymer materials.