Early-life exposure to natural and synthetic chemicals can impact acute and chronic health conditions. Here, a suspect screening workflow anchored on high-resolution mass spectrometry was applied to elucidate xenobiotics in breast milk and matching stool samples collected from Nigerian mother-infant pairs (n = 11) at three time points. Potential correlations between xenobiotic exposure and the developing gut microbiome, as determined by 16S rRNA gene amplicon sequencing, were subsequently explored. Overall, 12,192 and 16,461 features were acquired in the breast milk and stool samples, respectively. Following quality control and suspect screening, 562 and 864 features remained, respectively, with 149 of these features present in both matrices. Taking advantage of 242 authentic reference standards measured for confirmatory purposes of food bio-actives and toxicants, 34 features in breast milk and 68 features in stool were identified and semi-quantified. Moreover, 51 and 78 features were annotated with spectral library matching, as well as 416 and 652 by in silico fragmentation tools in breast milk and stool, respectively. The analytical workflow proved its versatility to simultaneously determine a diverse panel of chemical classes including mycotoxins, endocrine-disrupting chemicals (EDCs), antibiotics, plasticizers, perfluorinated alkylated substances (PFAS), and pesticides, although it was originally optimized for polyphenols. Spearman rank correlation of the identified features revealed significant correlations between chemicals of the same classification such as polyphenols. One-way ANOVA and differential abundance analysis of the data obtained from stool samples revealed that molecules of plant-based origin elevated as complementary foods were introduced to the infants' diets. Annotated compounds in the stool, such as tricetin, positively correlated with the genus Blautia. Moreover, vulgaxanthin negatively correlated with Escherichia-Shigella. Despite the limited sample size, this exploratory study provides high-quality exposure data of matched biospecimens obtained from mother-infant pairs in sub-Saharan Africa and shows potential correlations between the chemical exposome and the gut microbiome.
Background: Despite the importance of the deltoid to shoulder biomechanics, very few studies have quantified the three-dimensional shape, size, or quality of the deltoid muscle, and no studies have correlated these measurements to clinical outcomes after anatomic (aTSA) and/or reverse (rTSA) total shoulder arthroplasty in any statistically/scientifically relevant manner. Methods: Preoperative computer tomography (CT) images from 1057 patients (585 female, 469 male; 799 primary rTSA and 258 primary aTSA) of a single platform shoulder arthroplasty prosthesis (Equinoxe; Exactech, Inc., Gainesville, FL) were analyzed in this study. A machine learning (ML) framework was used to segment the deltoid muscle for 1057 patients and quantify 15 different muscle characteristics, including volumetric (size, shape, etc.) and intensity-based Hounsfield (HU) measurements. These deltoid measurements were correlated to postoperative clinical outcomes and utilized as inputs to train/test ML algorithms used to predict postoperative outcomes at multiple postoperative timepoints (1 year, 2-3 years, and 3-5 years) for aTSA and rTSA. Results: Numerous deltoid muscle measurements were demonstrated to significantly vary with age, gender, prosthesis type, and CT image kernel; notably, normalized deltoid volume and deltoid fatty infiltration were demonstrated to be relevant to preoperative and postoperative clinical outcomes after aTSA and rTSA. Incorporating deltoid image data into the ML models improved clinical outcome prediction accuracy relative to ML algorithms without image data, particularly for the prediction of abduction and forward elevation after aTSA and rTSA. Analyzing ML feature importance facilitated rank-ordering of the deltoid image measurements relevant to aTSA and rTSA clinical outcomes. Specifically, we identified that deltoid shape flatness, normalized deltoid volume, deltoid voxel skewness, and deltoid shape sphericity were the most predictive image-based features used to predict clinical outcomes after aTSA and rTSA. Many of these deltoid measurements were found to be more predictive of aTSA and rTSA postoperative outcomes than patient demographic data, comorbidity data, and diagnosis data. Conclusions: While future work is required to further refine the ML models, which include additional shoulder muscles, like the rotator cuff, our results show promise that the developed ML framework can be used to evolve traditional CT-based preoperative planning software into an evidence-based ML clinical decision support tool.
Glioma, with its heterogeneous microenvironments and genetic subtypes, presents substantial challenges for treatment prediction and development. We integrated 3D bioprinting and multi-algorithm machine learning as a novel approach to enhance the assessment and understanding of glioma treatment responses and microenvironment characteristics. The bioprinted patient-derived glioma tissues successfully recapitulated molecular properties and drug responses of native tumors. We then developed GlioML, a machine learning workflow incorporating nine distinct algorithms and a weighted ensemble model that generated robust gene expression-based predictors, each reflecting the diverse action mechanisms of various compounds and drugs. The ensemble model superseded the performance of all individual algorithms across diverse in vitro systems, including sphere cultures, complex 3D bioprinted multicellular models, and 3D patient-derived tissues. By integrating bioprinting, the evaluative scope of the treatment expanded to T cell-related therapy and anti-angiogenesis targeted therapy. We identified promising compounds and drugs for glioma treatment and revealed distinct immunosuppressive or angiogenic myeloid-infiltrated tumor microenvironments. These insights pave the way for enhanced therapeutic development for glioma and potentially for other cancers, highlighting the broad application potential of this integrative and translational approach.
D-mannose is widely used as non-antibiotic treatment for bacterial urinary tract infections. This application is based on a well-studied mechanism of binding to the type 1 bacterial pili and, therefore, blocking bacteria adhesion to the uroepithelial cells. To implement D-mannose into carrier systems, the mechanism of action of the sugar in the bladder environment is also relevant and requires investigation. Herein, two different MANNosylation strategies using mesoporous silica nanoparticles (MSNs) are described. The impact of different chemical linkers on bacterial adhesion and bladder cell response is studied via confocal microscopy imaging of the MSN interactions with the respective organisms. Cytotoxicity is assessed and the expression of Toll-like receptor 4 (TLR4) and caveolin-1 (CAV-1), in the presence or absence of simulated infection with bacterial lipopolysaccharide (LPS), is evaluated using the human urinary bladder cancer cell line T24. Further, localisation of the transcription factor NF-κB due to the MANNosylated materials is examined over time. The results show that MANNosylation modifies bacterial adhesion to the nanomaterials and significantly affects TLR4, caveolin-1, and NF-κB in bladder cells. These elements are essential components of the inflammatory cascade/pathogens response during urinary tract infections. These findings demonstrate that MANNosylation is a versatile tool to design hybrid nanocarriers for targeted biomedical applications.
The gut microbiome is associated with pathological neurophysiological evolvement in extremely premature infants suffering from brain injury. The exact underlying mechanism and its associated metabolic signatures in infants are not fully understood. To decipher metabolite profiles linked to neonatal brain injury, we investigate the fecal and plasma metabolome of samples obtained from a cohort of 51 extremely premature infants at several time points, using liquid chromatography (LC)-high-resolution mass spectrometry (MS)-based untargeted metabolomics and LC-MS/MS-based targeted analysis for investigating bile acids and amidated bile acid conjugates. The data are integrated with 16S rRNA gene amplicon gut microbiome profiles as well as patient cytokine, growth factor, and T cell profiles. We find an early onset of differentiation in neuroactive metabolites between infants with and without brain injury. We detect several bacterially derived bile acid amino acid conjugates in plasma and feces. These results provide insights into the early-life metabolome of extremely premature infants.
Bile Acids and Salts , Infant, Extremely Premature , Infant, Newborn , Infant , Humans , Chromatography, Liquid/methods , RNA, Ribosomal, 16S/genetics , Tandem Mass Spectrometry
Phonatory instabilities and involuntary register transitions can occur during singing. However, little is known regarding the mechanisms which govern such transitions. To investigate this phenomenon, we systematically varied laryngeal muscle activation and airflow in an in vivo canine larynx model during phonation. We calculated voice range profiles showing average nerve activations for all combinations of fundamental frequency (F0) and sound pressure level (SPL). Further, we determined closed-quotient (CQ) and minimum-posterior-area (MPA) based on high-speed video recordings. While different combinations of muscle activation favored different combinations of F0 and SPL, in the investigated larynx there was a consistent region of instability at about 400 Hz which essentially precluded phonation. An explanation for this region may be a larynx specific coupling between sound source and subglottal tract or an effect based purely on larynx morphology. Register transitions crossed this region, with different combinations of cricothyroid and thyroarytenoid muscle (TA) activation stabilizing higher or lower neighboring frequencies. Observed patterns in CQ and MPA dependent on TA activation reproduced patterns found in singers in previous work. Lack of control of TA stimulation may result in phonation instabilities, and enhanced control of TA stimulation may help to avoid involuntary register transitions, especially in the singing voice.
Laryngeal Muscles , Vocalization, Animal , Animals , Dogs , Laryngeal Muscles/physiology , Phonation/physiology , Sound , Video Recording
Background: Lumbar spine pathology (LSP) is a common source of low back or leg pain, and paraspinal muscle in these patients demonstrates fatty and fibrotic infiltration, and cellular degeneration that do not reverse with exercise-based rehabilitation. However, it is unclear of this lack of response is due to insufficient exercise stimulus, or an inability to mount a growth response. The purpose of this study was to compare paraspinal muscle gene expression between individuals with LSP who do and do not undergo an acute bout of resistance exercise. Methods: Paraspinal muscle biopsies were obtained from 64 individuals with LSP undergoing spinal surgery. Eight participants performed an acute bout of machine-based lumbar extension resistance exercise preoperatively. Gene expression for 42 genes associated with adipogenic/metabolic, atrophic, fibrogenic, inflammatory, and myogenic pathways was measured, and differential expression between exercised and non-exercised groups was evaluated for (a) the full cohort, and (b) an age, gender, acuity, and etiology matched sub-cohort. Principal components analyses were used to identify gene expression clustering across clinical phenotypes. Results: The exercised cohort demonstrated upregulation of inflammatory gene IL1B, inhibition of extracellular matrix components (increased MMP3&9, decreased TIMP1&3, COL1A1) and metabolic/adipogenic genes (FABP4, PPARD, WNT10B), and downregulation of myogenic (MYOD, ANKRD2B) and atrophic (FOXO3) genes compared to the non-exercised cohort, with similar patterns in the matched sub-analysis. There were no clinical phenotypes significantly associated with gene expression profiles. Conclusion: An acute bout of moderate-high intensity resistance exercise did not result in upregulation of myogenic genes in individuals with LSP. The response was characterized by mixed metabolic and fibrotic gene expression, upregulation of inflammation, and downregulation of myogenesis.
Mycotoxins are toxic chemicals that adversely affect human health. Here, we assessed the influence of mycotoxin exposure on the longitudinal development of early life intestinal microbiota of Nigerian neonates and infants (NIs). Human biomonitoring assays based on liquid chromatography tandem mass spectrometry were applied to quantify mycotoxins in breast milk (n = 68) consumed by the NIs, their stool (n = 82), and urine samples (n = 15), which were collected longitudinally from month 1-18 postdelivery. Microbial community composition was characterized by 16S rRNA gene amplicon sequencing of stool samples and was correlated to mycotoxin exposure patterns. Fumonisin B1 (FB1), FB2, and alternariol monomethyl ether (AME) were frequently quantified in stool samples between months 6 and 18. Aflatoxin M1 (AFM1), AME, and citrinin were quantified in breast milk samples at low concentrations. AFM1, FB1, and ochratoxin A were quantified in urine samples at relatively high concentrations. Klebsiella and Escherichia/Shigella were dominant in very early life stool samples (month 1), whereas Bifidobacterium was dominant between months 3 and 6. The total mycotoxin levels in stool were significantly associated with NIs' gut microbiome composition (PERMANOVA, p < 0.05). However, no significant correlation was observed between specific microbiota and the detection of certain mycotoxins. Albeit a small cohort, this study demonstrates that mycotoxins may influence early life gut microbiome composition.
Gastrointestinal Microbiome , Mycotoxins , Infant , Infant, Newborn , Female , Humans , Mycotoxins/urine , Biological Monitoring , RNA, Ribosomal, 16S , Tandem Mass Spectrometry/methods , Food Contamination/analysis
INTRODUCTION: Changes within the maternal microbiome during the last trimester of pregnancy and the determinants of the subsequent neonatal microbiome establishment after delivery by elective cesarean section are described. MATERIAL AND METHODS: Maternal vaginal and rectal microbiome samples were collected in the last trimester and before cesarean section; intrauterine cavity, placenta, neonatal buccal mucosa, skin, and meconium samples were obtained at birth; neonatal sample collection was repeated 2-3 days postnatally. Microbial community composition was analyzed by 16S rRNA gene amplicon sequencing. Relative abundance measurements of amplicon sequencing variants and sum counts at higher taxonomic levels were compared to test for significant overlap or differences in microbial community compositions. CLINICALTRIALS: gov ID: NCT04489056. RESULTS: A total of 30 mothers and their neonates were included with available microbiome samples for all maternal, intrauterine cavity and placenta samples, as well as for 18 of 30 neonates. The composition of maternal vaginal and rectal microbiomes during the last trimester of healthy pregnancies did not significantly change (permutational multivariate analysis of variance [PERMANOVA], p > 0.05). No robust microbial signature was detected in the intrauterine cavity, placenta, neonatal buccal mucosa, skin swabs, or meconium samples collected at birth. After birth, the neonatal microbiome was rapidly established, and significantly different microbial communities were detectable 2-3 days postnatally in neonate buccal mucosa and stool samples (PERMANOVA, p < 0.01). CONCLUSIONS: Maternal vaginal and rectal microbiomes in healthy pregnancies remain stable during the third trimester. No microbial colonization of the neonate was observed before birth in healthy pregnancies. Neonatal microbiomes in infants delivered by cesarean section displayed a taxonomic composition distinct from maternal vaginal and rectal microbiomes at birth, indicating that postnatal exposure to the extrauterine environment is the driving source of initial neonatal microbiome development in this cohort.
Gastrointestinal Microbiome , Microbiota , Female , Humans , Infant, Newborn , Pregnancy , Cesarean Section , Longitudinal Studies , Prospective Studies , RNA, Ribosomal, 16S/genetics
While there are lighthouse examples of microbiome research in sub-Saharan Africa (SSA), a significant proportion of local researchers face several challenges. Here, we highlight prevailing issues limiting microbiome research in SSA and suggest potential technological, societal, and research-based solutions. We emphasize the need for considerable investment in infrastructures, training, and appropriate funding to democratize modern technologies with a view to providing useful data to improve human health.
Microbiota , Humans , Africa South of the Sahara
The International Liaison Committee on Resuscitation engages in a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation and first aid science. Draft Consensus on Science With Treatment Recommendations are posted online throughout the year, and this annual summary provides more concise versions of the final Consensus on Science With Treatment Recommendations from all task forces for the year. Topics addressed by systematic reviews this year include resuscitation of cardiac arrest from drowning, extracorporeal cardiopulmonary resuscitation for adults and children, calcium during cardiac arrest, double sequential defibrillation, neuroprognostication after cardiac arrest for adults and children, maintaining normal temperature after preterm birth, heart rate monitoring methods for diagnostics in neonates, detection of exhaled carbon dioxide in neonates, family presence during resuscitation of adults, and a stepwise approach to resuscitation skills training. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, using Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces list priority knowledge gaps for further research. Additional topics are addressed with scoping reviews and evidence updates.
Cardiopulmonary Resuscitation , Emergency Medical Services , Out-of-Hospital Cardiac Arrest , Premature Birth , Adult , Female , Child , Infant, Newborn , Humans , First Aid , Consensus , Out-of-Hospital Cardiac Arrest/therapy , Cardiopulmonary Resuscitation/methods
Fixing palmar ulnar corner fragments of distal radial fractures can be challenging. We described the palmar ulnar corner fragment morphology in a retrospective cohort study of 40 patients who underwent preoperative wrist computed tomography scans. Palmar ulnar corner fractures were categorized based on articular cross-sectional area, sagittal angulation relative to the radius long axis, palmar cortical length, radioulnar width and associated palmar radiocarpal subluxation. Three types emerged: type 1 fragments involved 37% (SD 10) of the radiocarpal articular surface and were extended in the sagittal plane; type 2 fragments involved 28% (SD 10) of the articular surface and had a long palmar cortex, of which 57% had palmar carpal subluxation; and type 3 fragments involved 13% (SD 2) of the articular surface, had a short palmar cortex and all had palmar carpal subluxation. Understanding palmar ulnar corner fragment morphology may guide optimal reduction and fixation strategy and prevent palmar radiocarpal subluxation, especially in type 3 fractures.Level of evidence IV.
Joint Dislocations , Radius Fractures , Ulna Fractures , Humans , Retrospective Studies , Radius Fractures/diagnostic imaging , Radius Fractures/surgery , Fracture Fixation, Internal/methods , Tomography, X-Ray Computed , Wrist Joint , Joint Dislocations/surgery
OBJECTIVE: Exercise-associated dehydration is a common problem, especially at sporting events. Although there are recommendations to drink a certain volume per kg body mass lost after exercise, there is no clear guidance about the type of rehydration beverage. The aim of this systematic review is to assess the effectiveness of carbohydrate-electrolyte solutions as a rehydration solution for exercise-associated dehydration. DATA SOURCES: Medline (via the PubMed interface), Embase and the Cochrane Library were searched for relevant studies. The search is up to date until June 2022. STUDY SELECTION: Controlled trials involving adults and children were included if dehydration was the result of physical exercise and if drinking carbohydrate-electrolyte solutions, of any percentage carbohydrate, was compared with drinking water. All languages were included as long as an English abstract was available. DATA EXTRACTION: Data on study design, study population, interventions, outcome measures and study limitations were extracted from each included article. Certainty was assessed using GRADE. DATA SYNTHESIS: Out of 3485 screened articles, 19 studies were included that assessed carbohydrate-electrolyte solutions (0% - 9% carbohydrate) compared with water. Although there is variability amongst the identified studies, drinking 0-3.9% and, especially, 4-9% carbohydrate-electrolyte (CE) solution may be effective for rehydration. CONCLUSIONS: A potential beneficial effect of drinking CE drinks compared with water was seen for many of the reviewed outcomes. Commercial CE drinks (ideally 4-9% CE drinks or alternatively 0-3.9% CE drinks) could be suggested for rehydration in persons with exercise associated dehydration when whole foods are not available.
OBJECTIVE: Dehydration associated with exertion is a commonly encountered condition in the first aid setting, particularly at outdoor sporting events. Part I of this back-to-back review demonstrated that commercial sports drinks can be suggested for effective restoration of fluid balance in dehydrated persons. This systematic review was undertaken to compare alternative liquids, such as milk, beer, and coconut water, with water for effective oral rehydration after prolonged exercise. DATA SOURCES: Cochrane Library, PubMed, and Embase were searched for relevant literature in June 2022. STUDY SELECTION: Controlled experimental and observational studies involving adults and children were included when dehydration was induced by physical exercise and oral rehydration fluids were administered and compared with regular water. No additional food intake accompanied the rehydration drinks or water. Articles in all languages were included if an English abstract was available. DATA EXTRACTION: The study design, study population, intervention, outcome measures, and study limitations were extracted from each included article. DATA SYNTHESIS: Out of 3485 records, 11 studies were included comparing skim or low-fat milk, coconut water, and beer (0-5% alcohol) with water. Four studies showed that drinking skim or low-fat milk, without additional food intake, led to a statistically significant improved volume/hydration status when compared with drinking water. In three trials, no significant differences were shown at multiple timepoints for outcomes related to volume and hydration status following rehydration with fresh coconut water compared with water. Lastly, there is insufficient evidence to recommend beer for rehydration (0-5% alcohol). CONCLUSIONS: Consuming skim or low-fat cow's milk without additional food as compared with water appears to improve volume/hydration status in persons with exercise-induced dehydration. However, evidence is of very low certainty and should be interpreted with caution.
Prebiotics are defined as non-digestible dietary components that promote the growth of beneficial gut microorganisms. In many cases, however, this capability is not systematically evaluated. Here, we develop a methodology for determining prebiotic-responsive bacteria using the popular dietary supplement inulin. We first identify microbes with a capacity to bind inulin using mesoporous silica nanoparticles functionalized with inulin. 16S rRNA gene amplicon sequencing of sorted cells revealed that the ability to bind inulin was widespread in the microbiota. We further evaluate which taxa are metabolically stimulated by inulin and find that diverse taxa from the phyla Firmicutes and Actinobacteria respond to inulin, and several isolates of these taxa can degrade inulin. Incubation with another prebiotic, xylooligosaccharides (XOS), in contrast, shows a more robust bifidogenic effect. Interestingly, the Coriobacteriia Eggerthella lenta and Gordonibacter urolithinfaciens are indirectly stimulated by the inulin degradation process, expanding our knowledge of inulin-responsive bacteria.
Gastrointestinal Microbiome , Inulin , Inulin/metabolism , Gastrointestinal Microbiome/genetics , RNA, Ribosomal, 16S/genetics , Bacteria , Prebiotics
The International Liaison Committee on Resuscitation engages in a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation and first aid science. Draft Consensus on Science With Treatment Recommendations are posted online throughout the year, and this annual summary provides more concise versions of the final Consensus on Science With Treatment Recommendations from all task forces for the year. Topics addressed by systematic reviews this year include resuscitation of cardiac arrest from drowning, extracorporeal cardiopulmonary resuscitation for adults and children, calcium during cardiac arrest, double sequential defibrillation, neuroprognostication after cardiac arrest for adults and children, maintaining normal temperature after preterm birth, heart rate monitoring methods for diagnostics in neonates, detection of exhaled carbon dioxide in neonates, family presence during resuscitation of adults, and a stepwise approach to resuscitation skills training. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, using Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces list priority knowledge gaps for further research. Additional topics are addressed with scoping reviews and evidence updates.
Cardiopulmonary Resuscitation , Emergency Medical Services , Out-of-Hospital Cardiac Arrest , Premature Birth , Adult , Female , Child , Infant, Newborn , Humans , First Aid , Consensus , Out-of-Hospital Cardiac Arrest/diagnosis , Out-of-Hospital Cardiac Arrest/therapy
Increasing evidence shows that many human-targeted drugs alter the gut microbiome, leading to implications for host health. However, much less is known about the mechanisms by which drugs target the microbiome and how drugs affect microbial function. Here we combined quantitative microbiome profiling, long-read metagenomics, stable isotope probing and single-cell chemical imaging to investigate the impact of two widely prescribed nervous system-targeted drugs on the gut microbiome. Ex vivo supplementation of physiologically relevant concentrations of entacapone or loxapine succinate to faecal samples significantly impacted the abundance of up to one third of the microbial species present. Importantly, we demonstrate that the impact of these drugs on microbial metabolism is much more pronounced than their impact on abundances, with low concentrations of drugs reducing the activity, but not the abundance of key microbiome members like Bacteroides, Ruminococcus or Clostridium species. We further demonstrate that entacapone impacts the microbiome due to its ability to complex and deplete available iron, and that microbial growth can be rescued by replenishing levels of microbiota-accessible iron. Remarkably, entacapone-induced iron starvation selected for iron-scavenging organisms carrying antimicrobial resistance and virulence genes. Collectively, our study unveils the impact of two under-investigated drugs on whole microbiomes and identifies metal sequestration as a mechanism of drug-induced microbiome disturbance.
Host phylogeny and the environment play vital roles in shaping animal microbiomes. However, the effects of these variables on the diversity and richness of the gut microbiome in different bioclimatic zones remain underexplored. In this study, we investigated the effects of host phylogeny and bioclimatic zone on the diversity and composition of the gut microbiota of two heterospecific rodent species, the spiny mouse Acomys cahirinus and the house mouse Mus musculus, in three bioclimatic zones of the African Great Rift Valley (GRV). We confirmed host phylogeny using the D-loop sequencing method and analyzed the influence of host phylogeny and bioclimatic zone parameters on the rodent gut microbiome using high-throughput amplicon sequencing of 16S rRNA gene fragments. Phylogenetic analysis supported the morphological identification of the rodents and revealed a marked genetic difference between the two heterospecific species. We found that bioclimatic zone had a significant effect on the gut microbiota composition while host phylogeny did not. Microbial alpha diversity of heterospecific hosts was highest in the Mediterranean forest bioclimatic zone, followed by the Irano-Turanian shrubland, and was lowest in the Sudanian savanna tropical zone. The beta diversity of the two rodent species showed significant differences across the Mediterranean, Irano-Turanian, and Sudanian regions. The phyla Firmicutes and Bacteroidetes were highly abundant, and Deferribacterota, Cyanobacteria and Proteobacteria were also prominent. Amplicon sequence variants (ASVs) were identified that were unique to the Sudanian bioclimatic zone. The core microbiota families recovered in this study were consistent among heterospecific hosts. However, diversity decreased in conspecific host populations found at lower altitudes in Sudanian bioclimatic zone. The composition of the gut microbiota is linked to the adaptation of the host to its environment, and this study underscores the importance of incorporating climatic factors such as elevation and ambient temperature, in empirical microbiome research and is the first to describe the rodent gut microbiome from the GRV.
The ability to precisely control a scaffold's microstructure and geometry with light-based three-dimensional (3D) printing has been widely demonstrated. However, the modulation of scaffold's mechanical properties through prescribed printing parameters is still underexplored. This study demonstrates a novel 3D-printing workflow to create a complex, elastomeric scaffold with precision-engineered stiffness control by utilizing machine learning. Various printing parameters, including the exposure time, light intensity, printing infill, laser pump current, and printing speed were modulated to print poly (glycerol sebacate) acrylate (PGSA) scaffolds with mechanical properties ranging from 49.3 ± 3.3 kPa to 2.8 ± 0.3 MPa. This enables flexibility in spatial stiffness modulation in addition to high-resolution scaffold fabrication. Then, a neural network-based machine learning model was developed and validated to optimize printing parameters to yield scaffolds with user-defined stiffness modulation for two different vat photopolymerization methods: a digital light processing (DLP)-based 3D printer was utilized to rapidly fabricate stiffness-modulated scaffolds with features on the hundreds of micron scale and a two-photon polymerization (2PP) 3D printer was utilized to print fine structures on the submicron scale. A novel 3D-printing workflow was designed to utilize both DLP-based and 2PP 3D printers to create multiscale scaffolds with precision-tuned stiffness control over both gross and fine geometric features. The described workflow can be used to fabricate scaffolds for a variety of tissue engineering applications, specifically for interfacial tissue engineering for which adjacent tissues possess heterogeneous mechanical properties (e.g., muscle-tendon).
