Sections Of Specimens Research Articles

Experimental and Numerical Study on the Bending Behavior of Satin-Woven SiCf/SiC Composites

The present research intends to explore the progressive failure in the case of five-harness SiCf/SiC satin-woven sheet composites consisting of twelve layers using a combination of numerical and experimental methods. For derivation and characterization of the bending behavior, a three-point bending procedure was used under conditions of atmospheric temperature. A charge-coupled device (CCD) camera was used to monitor the initiation and evolution of the failures. Variations in the strain fields were quantified following the digital image correlation (DIC) approach, whereas the resultant failure markings were elucidated by conducting microscopic assessments. The 3D finite element modeling (FEM) of the experiment was accomplished via ABAQUS/Explicit, thereby reproducing the material performance. A 3D-modified theory of the Tsai-Wu failure initiation was executed by exploiting the VUMAT subroutine. The evolutionary rule was used to study the complementary failure. A cohesive zone element of the composite interlayer was utilized to mimic the intra-deformation interfacial damage. The DIC-based experimental values of the strain fields agreed favorably with the numerical computations and the strength value error was less than 10%. An in-depth investigation was performed concerning the advantage of the 3D modeling approach to study the applicability of the method for the foreseeable distribution of the complex field parameters (e.g., progressive failure deposition and free edge effect) inside the critical specimen section.

Identification of cell types in multiplexed in situ images by combining protein expression and spatial information using CELESTA.

Advances in multiplexed in situ imaging are revealing important insights in spatial biology. However, cell type identification remains a major challenge in imaging analysis, with most existing methods involving substantial manual assessment and subjective decisions for thousands of cells. We developed an unsupervised machine learning algorithm, CELESTA, which identifies the cell type of each cell, individually, using the cell's marker expression profile and, when needed, its spatial information. We demonstrate the performance of CELESTA on multiplexed immunofluorescence images of colorectal cancer and head and neck squamous cell carcinoma (HNSCC). Using the cell types identified by CELESTA, we identify tissue architecture associated with lymph node metastasis in HNSCC, and validate our findings in an independent cohort. By coupling our spatial analysis with single-cell RNA-sequencing data on proximal sections of the same specimens, we identify cell-cell crosstalk associated with lymph node metastasis, demonstrating the power of CELESTA to facilitate identification of clinically relevant interactions.

DIC-based approach to predict post necking behavior for AA6061, AA7075 and their friction stir welded joints

In a tensile test, the precise measurement of the area at the necking section is crucial for predicting the post-necking true stress-strain behavior. In the conventional theoretical method, this area is linked to the engineering strain using the incompressibility criteria, which is not applicable in the post necking domain. The present work proposes a digital image correlation (DIC)-based technique with two cameras for estimating real-time area reduction at a necking section of a rectangular tensile specimen during a uniaxial tensile test. In the current study, the area at a given section is computed by measuring strain synchronously in the width and thickness planes of a tensile specimen and translating the change in lengths in both planes into a global coordinate system. The area computation of the proposed approach is successfully validated by measuring the necking area of a terminated tensile specimen (stopped before fracture) by optical microscope to an error in the range of 0.12–1.10%. Following verification, the post necking behaviors of aluminum alloys such as AA6061-T6 and AA7075-T6 are assessed. The current approach is further implemented to evaluate the area reduction and post necking behavior of similar and dissimilar friction stir welding (FSW) joints of AA6061-T6 and AA7075-T6 that possess process induced microstructural inhomogeneity. The current experimental approach effectively assessed the area reduction of a similar and dissimilar FSW joint influenced by weld inhomogeneity, which is otherwise complicated to contemplate using an analytical approach.

The Theory of Critical Distances to assess the effect of cracks/manufacturing defects on the static strength of 3D-printed concrete

The present paper deals with the use of the Theory of Critical Distances to model the detrimental effect of cracks and manufacturing defects in 3D-printed concrete subjected to static loading. The robustness of the proposed approach was assessed against a number of experimental results that were generated by testing, under three-point bending, 3D-printed rectangular section specimens weakened by saw-cut crack-like sharp notches, surface roughness (due to the extrusion filaments) and manufacturing defects. The sound agreement between experiments and predictive model allowed us to demonstrate that the Theory of Critical Distances is not only a reliable design approach, but also a powerful tool suitable for guiding and informing effectively the additive manufacturing process.

Melt pool temperature measurement and monitoring during laser powder bed fusion based additive manufacturing via single-camera two-wavelength imaging pyrometry (STWIP)

Melt pool (MP) temperature is one of the determining factors and a key signature for evaluating the properties of printed components in metal additive manufacturing (AM). The state-of-the-art measurement systems are hindered, primarily by the large-scale data acquisition and processing demands. In this work, we introduce a novel coaxial, high-speed, single-camera two-wavelength imaging pyrometer (STWIP) system as opposed to the typical utilization of multiple cameras for measuring MP temperature profiles in laser powder bed fusion (LPBF) processes. Developed on a commercial LPBF machine (EOS M290), the STWIP system demonstrated its ability to quantitatively monitor the MP temperature and its variation for 50 layers at high framerates (>30,000 fps) for a real-world application (standard fatigue specimens) print. High performance computing is employed to analyze the acquired big data (MP images), for determining each MP's average temperature and 2D temperature profile. The MP temperature evolution in the gage section of a fatigue specimen is also examined at a temporal resolution of 1 ms, by evaluating the MP temperatures in the samples' first, middle, and last layers. This paper is first of its kind on monitoring MP temperature distribution and evolution at such a large, detailed scale for longer durations in practical applications.

Temperature-induced enhancement of tensile strength of perforated Ti–6Al–4V sheet revealed through mechanical-thermal coupling quasi-static tension

In order to investigate the effect of temperature on the tensile strength of perforated Ti–6Al–4V (TC4) alloy, the tensile mechanical properties of TC4 alloy with various micro-hole array distributions were obtained at a temperature in a range from 20 °C to 500 °C by using a novel mechanical-thermal coupling tensile test instrument developed by ourselves. The experimental results showed that the tensile strength of all types of TC4 alloy specimens decreased with the increase in temperature, and the elastic modulus of most types of TC4 alloy specimens decreased with the increase in temperature. The tensile strength of the perforated specimen iii was 14.8% lower than that of the solid specimen and the elastic modulus of perforated specimen ii was 5.5% lower than that of the solid specimen at room temperature (RT), and all types of the perforated specimens continued to exhibit relatively lower tensile strengths and elastic modulus at 180 °C and 340 °C. Abnormally, the tensile strength of the perforated specimen iii was 2.1% higher than that of the solid specimen and the elastic modulus of perforated specimen ii was 23% higher than that of the solid specimen at 500 °C. With the increase of temperature from 20 °C to 500 °C, the fracture mode of the solid specimen gradually changed from equiaxed dimple to shear dimple. Regarding the perforated specimens, the cracks and dimples adjacent to the holes gradually decreased as a function of temperature. The existence of prefabricated holes in the specimens dissipated part of the thermal stress, maintained the integrity of the micro-hole structure, and made the nearby section relatively flat, which induced a relatively higher tensile strength and structural stiffness at an elevated temperature. The relatively lower stress in the gauge section of the perforated specimens obtained through finite element analysis also indicated the temperature-induced enhancement of tensile strength.

Fast characterization framework for creep microstructure of a nickel-based SX superalloy with high-throughput experiments and deep learning methods

Nickel-based single crystal (SX) superalloys are the key materials of turbine blades in aircrafts, that the microstructure evolution during high temperature creep has critical effects on the thermo-mechanical properties. Research on microstructure evolution and establishing the quantitative relationship between microstructure evolution and creep conditions are of great significance for service safety assessment of nickel-based SX superalloys. High generation nickel-based SX superalloys generally have high cost on account of precision casting and the addition of Re and Ru which are rare and precious metals. Hence, it is necessary to develop a rapid characterization and analysis approach in terms of microstructure features of nickel-based SX superalloys. In this study, we integrated high-throughput experiment, large-scale high-resolution characterization and high-throughput quantitative analysis techniques to establish an efficient method for investigating the microstructure evolution of nickel-based SX superalloys during high temperature creep. The high temperature interrupted creep tests were carried out on the variable section specimens with arc surface to acquire the microstructures which are changed with creep stress continuously. High-resolution SEM with ALTLAS module was employed to quickly characterize the large-scale microstructure throughout the universal stress scale. Based on U-Net deep learning algorithm, an automatic dendrite identification model was established to segment the dendrite region quickly and accurately. And then, the γ/γ’ microstructure parameters of dendrite region were continuously quantitated using a logical algorithm. The quantitative correlation between microstructure evolution and creep conditions of nickel-based SX superalloys could be established, which shows tremendous potential and significance in the service safety assessment of nickel-based SX superalloys. • An integrated method is proposed for rapid characterization of microstructure features of SX superalloys. • The arc surface specimen can generate continuously distributed microstructure. • U-Net model can achieve dendrite region recognition quickly and accurately. • The γ/γ’ microstructure parameters were continuously quantitated using a logical algorithm.

Experimental Study of 3D Micro-CT on Meso-Structure Evolution of Coal Samples with Different Coal Grades under the Action of Temperature

In the three-dimensional micro-CT experiment system, the room temperature is set to 300°C when different coal samples (lignite, anthracite, lean coal and gas coal) are observed for mesoscopic observation. The evolution regularity of mesoscopic structure is analyzed according to the CT scan of coal samples under different temperatures and three sections of scanning images, and by ImageJ image processing software, image processing, and analysis of the characteristics of the profile, the following conclusions are obtained: (1) Coal specimen will have an overall expansion deformation along with the rise of temperature. The sample expansion can be divided into two types: outward expansion and inward expansion. Outward expansion means that the expansion of the skeleton extends outward from the adjacent pores, while inward expansion means that the solid skeleton intrudes into the adjacent pores. When the temperature rises, the outward expansion and inward expansion occur simultaneously. The dominant expansion mode is influenced by the type of coal sample and the temperature value. (2) With the increase of temperature, coal and anthracite coal specimen pore fissure structure shows an expansion tendency before contraction, while gas coal and lean coal show reverse patterns; in addition to the above the reason of the difference vitrinite differences, one must also consider selected specimen original porosity and mechanical physical properties, such as a combination of other factors. (3) In the temperature range of 100–200°C, when the temperature increases at the same rate, lignite porosity increases the most, followed by gas coal, lean coal, and anthracite. (4) There are certain differences in the variation trends of the pixel proportions of the three sections of the coal specimen, and the temperature values of the three curves at the maximum pixel point are also different, which indicates that the expansion of each point in the coal specimen with the change of temperature is not completely synchronous, and the physical and mechanical properties of the sample are heterogeneous.

Variations in tension wood characteristics of Populus alba under alternate bending, nitrogen fertilization, and gibberellin treatments

Summary Reaction wood formation (tension wood) in trees such as poplar is a response to stress and environmental factors. Tension wood is a rich source of cellulose that can be used for products including paper or biofuels and is thus a target product in forestry. This study aimed to evaluate the formation of tension wood in two-year-old saplings of Populus alba by using alternate bending, nitrogen fertilization, and gibberellin hormone. Saplings were bent alternately in one or another direction every month during the growing season, fertilized twice at the beginning and in the middle of the growing season, and treated with gibberellin early in the growing season. The physical and anatomical characteristics of the wood were studied after the end of the growing season. Evaluation of transverse sections of specimens stained with safranin/Astra-blue showed that, compared with straight saplings, alternate bending saplings had a wider tension wood area in the growth ring and clear formation of a gelatinous layer. The wood of alternate bending saplings with nitrogen fertilization and gibberellin hormone had a higher wood density, greater longitudinal shrinkage, and less radial and tangential shrinkage than saplings with other treatments. Moreover, the alternate bending saplings treated with nitrogen fertilization and gibberellin hormone had tension wood with the largest vessels, the lowest vessel density, and the smallest total vessel lumen area than saplings with other treatments. Wood fibers of treated saplings also had the thickest wall with the smallest fiber and lumen diameters. Overall, the bending treatment with the addition of nitrogen fertilization and gibberellin hormone was the most effective for the stimulation of tension wood formation in terms of volume and intensity.

Effect of geometric size deviation induced by machining on the vibration fatigue behavior of Ti‐6Al‐4V

AbstractTi‐6Al‐4V plates were machined simultaneously to achieve the reduced section of specimens with a wire‐cut electrical discharge machine (EDM). Geometric shape errors due to the cutting path deviation were discovered on many specimens after the final manufacture. High‐cycle fatigue tests were carried out on these symmetrical and asymmetrical shaped specimens. Probabilistic treatment was used to examine the occurrence probability of one or two cracks, and the fatigue failure mechanisms were investigated using scanning electron microscope (SEM). The objective of this work was to highlight the impact of the geometric size deviation on fatigue life and crack growth.

NEPHROPROTECTIVE EFFECT OF ACACIA SENEGAL (GUM ARABIC) AGAINST GENTAMICIN INDUCED NEPHROTOXICITY IN RATS

Objective: To explore the effects of Gum Arabic (Acacia Senegal) aqueous extract in contradiction of gentamicin induced nephrotoxicity in Wistar albino rats. Materials and Methods: Forty rats were randomly separated into 4 groups (n=10). Group A (negative control) received standard diet and water while group B (positive control) received gentamicin 80 mg/kg b. wt. /day via intra peritoneal (IP) route for six days. Groups C and D received Gum Arabic extract at 250 and 500 mg/kg b. wt. via oral route respectively for 10 days and concurrently with gentamicin 80 mg/kg b. wt. IP from day 5 for six days. The nephroprotective activity of Gum Arabic extract was evaluated by measuring the serum and urine biochemical parameters (creatinine, urea, total protein, albumin, sodium and potassium) and examining the histopathological sections of kidney specimen. The serum and urine data were subjected to analysis of variance (ANOVA). Results: In both serum and urine, the biochemical parameters in groups C and D were significantly improved compared to group B. The histopathological analysis of kidneys showed slight necrosis of glomeruli and tubules in group C compared to group B, while group D showed only hemorrhage and congestion in the glomeruli. Conclusion: These findings suggest that, Gum Arabic extract may possess a nephroprotective activity.

Anti-coking and anti-carburizing behavior of amorphous AlPO4 coating

The aim of the present study was to examine the anti-coking and anti-carburizing behavior of amorphous AlPO4 coating. So, aluminum phosphate composition was synthesized by sol-gel process and applied on the AISI 304 stainless steel by dip coating technique. Anti-coking performance was examined in a tube furnace at 1000 °C for 30 min under Ethane (C2H6) atmosphere. Carburizing test was performed in a sealed charcoal medium at 1100 °C for a total of 30 h exposure time. Phase composition of the samples was analyzed by X-Ray Diffraction (XRD) after coking and carburizing tests. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) were employed to study the morphology and elemental analysis of the samples after coke and carbon formation experiments. Microhardness indenter was applied on the cross section of the carbon-exposed specimens to plot the hardness profile through the carburizing zone. The results of the coking experiment revealed catalytic coke formed on the uncoated surface, while irregular spherical coke with no trace of catalytic coke was formed on the coated surface, indicating the great anti-coking performance of the amorphous AlPO4 coating. The results of pack-carburizing test demonstrated that the thickness of the carbide layer formed on the bare surface was ∼10 times greater than that of the coated sample. Hardness measurement for the amorphous AlPO4 coated sample detected lower values compared to those for the uncoated one at all distances from the surface, indicating less carbon diffusion occurred beneath the coated surface. In overall, the results declared that the amorphous AlPO4 coating could be a good candidate for surface protection of stainless steel against catalytic coke formation and carbon diffusion.

Mechanical Characteristics of Prestressed Concrete Curved Transition Section of Composite Bucket Foundations for Offshore Wind Turbines

The composite bucket foundation (CBF) consists of a concrete curved transition section, a concrete beam-slab system, and a suction caisson and is increasingly used as the foundation for offshore wind turbines. The curved transition section transmits the upper load from the tower to the foundation, and its force and transmission characteristics are related to the safety of the entire wind turbine structure. The arced transition section has the characteristics of complex geometry, load conditions, and large curvature. It is difficult to determine its bearing characteristics and force transmission system. In this paper, the boundary conditions and loading device of the CBF model test are designed, and three 1:20 arced transition section model specimens are made. The mechanical characteristic experiments of CBF are used to analyze the failure process, failure characteristics, and seismic performance of the structure. Results show that the cracking effect of the arced transition section after prestressing is obviously better than that of a reinforced concrete arced transition section structure. The arced transition section specimens equipped with prestressed tendons can increase the structural cracking load ratio by about 35% for reinforced concrete members. The energy dissipation capacity of the specimens has been significantly improved, and the material properties can be fully utilized. The failure mode of the arced transition section structure under horizontal reciprocating load shows the characteristics of bending and shear failure.

The histopathological findings in excised upper eyelids of patients with dermatochalasis following collagen cross-linking treatment.

To evaluate the histopathological effects of collagen cross-linking (CCL) on excised skin samples of patients undergoing upper eyelid blepharoplasty due to dermatochalasis. This study examined 74 excised eyelid skin samples from 37 dermatochalasis patients. Following an upper eyelid blepharoplasty, CCL with hypotonic riboflavin (0.1%) was applied. Both treated (right eyelid, CCL group) and untreated eyelid specimen (left eyelid, non-CCL group) sections were stained with hematoxylin-eosin and Masson's trichrome. The sections were evaluated for the following parameters: the collagen status (parallel, oblique, and perpendicular), the distance between collagen fibers, the diameter of collagen fibers, and the length of collagen fibers. There were no statistically significant differences in the collagen status, the distance between collagen fibers, the diameter of collagen fibers, and the length of collagen fibers between the CCL and non-CCL groups (p > 0.05 for all). Although the lack of statistically significant differences, the structure of the treated eyelid collagen fibers was more parallel in 48% of the participants than in the untreated ones. For male patients, a statistically significant shorter distance between collagen fibers was observed in the CCL group (8.05 ± 2.04µm) compared to the non-CCL group (9.97 ± 2.33µm) (p = 0.042). In this study, more parallel collagen structures and tightly packed collagen fibers were detected in eyelid samples following CCL treatment. The authors note that the results of this study may be promising for further research, so the effect of CCL therapy on the eyelid may be an interesting subject for the treatment of non-severe or surgically inadequately corrected dermatochalasis.

Contenido total de fenoles en frutos y cultivos in vitro de Bromelia karatas L.

Bromelia karatas L. is a species native from America, used in traditional medicine as an alternative in the treatment of diabetes mellitus. Overexploitation and change in land use have led to a drastic decline in species. In the present work, in vitro cultures were established from B. karatas seeds and their total phenolic content was determined. To promote the germination of the seeds several scarification treatments were tested. Furthermore, the seeds were cultured on Murashige & Skoog (MS) media containing different concentration of N-6 benzyladenine (BA) with 2,4-dichlorophenoxyacetic acid (2,4-D). Obtaining a higher percentage of germination (100%) when exposing the seeds to H2SO4 (98%, 5 min) was obtaining. Additionally, in in vitro cultures, the germination time was considerably reduced (36 times), compared to the data reported in the field. Highest percentage of callus induction of leaf sections (1.5 cm2) of adult specimens and plants germinated in vitro in MS media containing BA (1.0 mg • L-1) + 2,4-D (0.0, 0.5, 1.0, and 2.0 mg • L-1) was established. Mature fruits of B. karatas resulted in the greatest phenolic content (1,110 mg GAE • 100 g-1, biomass, dry weight (DW)) measured by the Folin–Ciocalteu reagent method, while the smallest content was recorded for callus and the leaves of in vitro seedling germinated recorded 205 and 741 mg GAE • 100 g-1 DW, respectively. These results provide novel data, which can be part of programs for sustainable use and conservation of this species of ethnobotanical importance.

Intraoperative near-infrared fluorescence imaging can identify pelvic nerves in patients with cervical cancer in real time during radical hysterectomy

PurposeRadical hysterectomy combined with pelvic lymphadenectomy is the standard treatment for early-stage cervical cancer, but unrecognized pelvic nerves are vulnerable to irreversible damage during surgery. This early clinical trial investigated the feasibility and safety of intraoperative near-infrared (NIR) fluorescence imaging (NIR-FI) with indocyanine green (ICG) for identifying pelvic nerves during radical hysterectomy for cervical cancer.MethodsSixty-six adults with cervical cancer were enrolled in this prospective, open-label, single-arm, single-center clinical trial. NIR-FI was performed in vivo to identify genitofemoral (GN), obturator (ON), and hypogastric (HN) nerves intraoperatively. The primary endpoint was the presence of fluorescence in pelvic nerves. Secondary endpoints were the ICG distribution in a nerve specimen and potential underlying causes of fluorescence emission in pelvic nerves.ResultsIn total, 63 patients were analyzed. The ON was visualized bilaterally in 100% (63/63) of patients, with a mean fluorescence signal-to-background ratio (SBR) of 5.3±2.1. The GN was identified bilaterally in 93.7% (59/63) of patients and unilaterally in the remaining 4 patients, with a mean SBR of 4.1±1.9. The HN was identified bilaterally in 81.0% (51/63) of patients and unilaterally in 7.9% (5/63) of patients, with a mean SBR of 3.5±1.3. ICG fluorescence was detected in frozen sections of a nerve specimen, and was mainly distributed in axons. No ICG-related complications were observed.ConclusionThis early clinical trial demonstrated the feasibility and safety of NIR-FI to visualize pelvic nerves intraoperatively. Thus, NIR-FI may help surgeons adjust surgical decision-making, avoid nerve damage, and improve surgical outcomes.Trial registrationClinicalTrials.gov NCT04224467

Experiments on perforated cold-formed built-up I-section beam-columns with longitudinal web and complex edge stiffeners

A built-up I-section with longitudinal web and complex edge stiffeners is expected to have better performance to resist against local and distortional buckling compared to built-up I-section without these. In this paper, the compression behavior of perforated cold-formed beams-columns with longitudinal web and complex edge stiffeners was experimentally studied between pined-ends. It contained 16 single section and 8 built-up section specimens, respectively. The above research was shown that the form of longitudinal stiffeners and built-up I-sections could effectively improve steel utilization and load-carrying capacity. For the single-limb section, effective centroid shift led to an eccentricity of the applied force and hence induced the maximum ultimate load achieved at a certain loading eccentricity, but not at concentricity. However, the built-up member was symmetrical along the center of the member and uniformly compressed on both sides, which was not affected by the above. It was noteworthy that the two adjacent single-limb webs of conventional built-up I-section exhibited some specific support to each other, but the deformation of the plate around the hole cannot be restricted. However, the section with web stiffeners shown an opposite result of the above situation. Meanwhile, the longitudinal stiffener can obviously resist the built-up members' elastic deformation under the same condition. In addition, a finite element model was developed and verified against experiments of perforated beam-columns. Finally, two different Direct Strength Method (DSM) formulas were used to calculate the ultimate bearing capacity of perforated beam-column members under eccentric load. The calculated results were compared. It can be seen that the DSM formula that considered the distortional and overall relative buckling was closer to the actual value.

Influence of void content on noise reduction characteristics of different asphalt mixtures using meso-structural analysis

In order to study the noise reduction behavior of asphalt pavements with different void contents, a two-dimensional (2D) level acoustic-structure coupled sound absorption model was constructed. The sound absorption effects of asphalt mixtures with different void ratios were qualitatively analyzed, and the variation law of their absorption coefficients was obtained. At the same time, the influence of void characteristics on noise reduction was analyzed using the meso-structure. The results show that: with the increase of the void ratio of asphalt mixture, the total area of voids in the specimen section increases; the number of voids in the specimen section decreases, while the average equivalent diameter of the voids increases; the fractal dimension of the voids in the section increases; the anti-dispersion ability and noise reduction effect of the asphalt mixture increase. The prediction model of sound absorption coefficient established in the study could predict the sound absorption coefficient of asphalt mixture, which provides a reference for practical application.

Identification of Gene Expression Profiles Associated with an Increased Risk of Post-Operative Recurrence in Crohn's Disease.

Ileocolonic resection is frequently needed in the course of Crohn's disease [CD] treatment and post-operative recurrence is extremely common. Our main objective was to analyse gene expression in the mucosa of CD patients at the time of surgery and at post-operative endoscopy, in order to identify predictors and mechanisms of early endoscopic recurrence. We conducted transcriptome analyses on ileal mucosa samples collected from inflamed sections of the surgical specimens [n = 200], from ileal resection margins [n = 149] and in the neo-terminal ileum 6 months after surgery [n = 122]; these were compared with non-inflammatory bowel disease controls [n = 25]. The primary endpoint was post-operative endoscopic recurrence at 6 months. We applied regression models to identify gene signatures predicting endoscopic recurrence. Chronic inflammation was associated with strong expression of inflammatory genes [IL-6, IL-8, IL-1B] and decreased expression of genes involved in metabolic processes, but with a high inter-individual heterogeneity. Gene signatures associated with early endoscopic recurrence were mainly characterized by upregulation of TNFα, IFNγ, IL23A and IL17A. Pathway analyses showed that upregulation of mitochondrial dysfunction within the inflamed sections and JAK/STAT at the ileal margin were predictive of post-operative recurrence. A combined model integrating these top pathway signatures improved the prediction of endoscopic recurrence [area under the curve of 0.79]. STAT3 phosphorylation at the surgical ileal margin was associated with severe recurrence at 6 months. We identified several biological pathways in surgical ileal mucosa specimens associated with an increased risk of disease recurrence. Integration of the JAK/STAT and mitochondrial dysfunction pathways in the clinical model improved the prediction of post-operative recurrence.

Local Bearing Capacity of Concrete Under the Interaction of Headed Bars

The application of reinforcement with headed bars is widely used in the construction industry. Moreover, when the net distance between headed bars is close, the concrete areas for distributing bearing under the headed bars will overlap with each other. The local bearing capacity of concrete will also be affected by the overlapping area. To evaluate the effect of the overlapping area on the local bearing capacity of concrete, the experimental study was conducted on 6 concrete pull-out specimens. Based on the pull-out test, the parameter that net distance between headed bars was researched. The failure modes of specimens can be divided into two types. The first failure mode was marked by the formation of the dovetail slot structure during the failure process, and the second failure mode was characterized by the formation of through cracks in the cross section of specimens. The pull-out test results show that the local bearing capacity of concrete decreases firstly with the increase of net distance and then increases with the increase of net distance. Therefore, the relationship between the ratio of net distance to the side length of headed bars and the percentage decrease value of the local bearing capacity were given for the two segments. In addition, the critical value of the two segments was also analyzed and the corresponding formulas were also proposed. In order to verify the accuracy of formulas for the two segments, the test data from the similar pull-out tests with two or three headed bars were collected. And the calculation was recalculated according to the method proposed in this paper. Based on the ratio of the test data to the calculated values, the average value, standard deviation, and coefficient of variation are 1.08, 0.12, and 0.11 for the descending segment, respectively. And the values are 1.21, 0.22, and 0.18 for the rising segment, respectively. It is proved that there is a high accuracy for the formulas and the calculation method for the local bearing capacity of concrete under the interaction of headed bars was established.