Layer Thickness Research Articles

Association of macular microcirculation with renal function in Chinese non-diabetic patients with hypertension.

The aim of this study was to investigate the association of macular microcirculation with renal function and the feasibility of using macular microcirculatory parameters to monitor renal function in Chinese non-diabetic patients with hypertension. This case-control study included 62 non-diabetic patients with hypertension, including 31 with renal dysfunction (estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m2) and 31 with normal renal function (eGFR ≥90 mL/min/1.73 m2). Age, sex and clinic blood pressure were matched between groups. Macular microcirculatory parameters of 124 eyes of the 62 patients were evaluated by optical coherence tomography (OCT) and OCT angiography (OCTA). In comparison with the patients with normal renal function, patients with renal dysfunction had lower macular superficial parafovea vessel density (18.6 vs. 19.4%, P = 0.029), macular cube average thickness (273.0 vs. 280.2 µm, P = 0.003), and average ganglion cell layer and inner plexiform layer (GCL-IPL) thickness (79.5 vs. 82.8 µm, P = 0.006), but similar macular central fovea vessel density and central fovea thickness (P ≥ 0.54). After adjustment for confounders, eGFR was significantly associated with macular superficial parafovea vessel density, cube average thickness and GCL-IPL thickness (P < 0.02). In detecting renal dysfunction, areas under the curve were 0.61, 0.66 and 0.65 for macular superficial parafovea vessel density, cube average thickness and GCL-IPL thickness. In non-diabetic patients with hypertension, macular superficial parafovea vessel density, cube average thickness and GCL-IPL thickness were significantly worse in patients with renal dysfunction than those with normal renal function. Using macular parameters to monitor renal function is feasible.

Improved conduction and orbital polarization in ultrathin LaNiO3 sublayer by modulating octahedron rotation in LaNiO3/CaTiO3 superlattices.

Artificial oxide heterostructures have provided promising platforms for the exploration of emergent quantum phases with extraordinary properties. Here, we demonstrate an approach to stabilize a distinct oxygen octahedron rotation (OOR) characterized by in the ultrathin LaNiO3 sublayers of the LaNiO3/CaTiO3 superlattices. Unlike the OOR in the LaNiO3 bare film, the OOR favors high conductivity, driving the LaNiO3 sublayer to a metallic state of ~100 K even when the layer thickness is as thin as 2 unit cells (u.c.). Simultaneously, strongly preferred occupation of orbital is achieved in LaNiO3 sublayers. The largest change of occupancy is as high as 35%, observed in the 2 u.c.-thick LaNiO3 sublayers sandwiched between 4 u.c.-thick CaTiO3 sublayers. X-ray absorption spectra indicate that the OOR pattern of LaNiO3 achieved in the LaNiO3/CaTiO3 heterostructures has significantly enhanced the Ni-3d/O-2p hybridization, stabilizing the metallic phase in ultrathin LaNiO3 sublayers. The present work demonstrates that modulating the mode of OOR through heteroepitaxial synthesis can modify the orbital-lattice correlations in correlated perovskite oxides, revealing hidden properties of the materials.

Influence of Solid Solution Treatment on Microstructure and Mechanical Properties of 20CrNiMo/Incoloy 825 Composite Materials

The utilization of 20CrNiMo/Incoloy 825 composite materials as high-pressure pipe manifold steel can not only improve the strength and hardness of the steel, but also improve its corrosion resistance. However, research on the heat treatment of 20CrNiMo/Incoloy 825 composite materials is still scarce. Thus, the aim of this study was to investigate the influence of solid solution treatment on the microstructure and properties of 20CrNiMo/Incoloy 825 composite materials. Firstly, the composite materials were subjected to solid solution treatment at temperatures ranging from 850 to 1100 °C with varied holding times of 1 h, 4 h, and 6 h. Microstructural analysis revealed that the solid solution treatment temperature had a more pronounced effect than the treatment time on the interface decarburization layer, carburization layer, and grain size. It was observed that the carburized layer thickness decreased while the decarburized layer thickness increased with an increase in the solid solution treatment temperature, oil cooling was found to enhance the hardness of the base layer of the composite materials, and the size of the original austenite grains of 20CrNiMo steel and Incoloy 825 increased with an increase in the solid solution treatment temperature. Secondly, the tensile properties, microhardness, and fracture morphology were evaluated after the composite materials underwent solid solution treatment at temperatures between 950 °C and 1100 °C for 1 h. The results indicated that increasing the solution temperature initially led to an increase in tensile strength and elongation after fracture, followed by a decrease; furthermore, the hardness of Incoloy 825 exhibited a declining trend, while the hardness of 20CrNiMo first decreased then increased. Thirdly, the shear properties and interfacial element diffusion of the composite materials were analyzed following solid solution treatment in a temperature range of 950 °C to 1100 °C for 1 h. The findings demonstrated that higher solid solution treatment temperatures induced full diffusion of Cr, Ni, and Fe atoms at the interface and softened the matrix, leading to an increase in the thickness of the diffusion layer and toughening of the composite interface. Therefore, the shear strength increased with an increase in the solid solution treatment temperature. Finally, the optimal solid solution treatment process for 20CrNiMo/Incoloy 825 composite materials was determined to be 1050 °C/1 h oil cooling, following which the composite materials had good comprehensive mechanical properties.

Highly-efficient (>70%) and Wide-spectral (400-1700 nm) sub-micron-thick InGaAs photodiodes for future high-resolution image sensors.

This paper demonstrates the novel approach of sub-micron-thick InGaAs broadband photodetectors (PDs) designed for high-resolution imaging from the visible to short-wavelength infrared (SWIR) spectrum. Conventional approaches encounter challenges such as low resolution and crosstalk issues caused by a thick absorption layer (AL). Therefore, we propose a guided-mode resonance (GMR) structure to enhance the quantum efficiency (QE) of the InGaAs PDs in the SWIR region with only sub-micron-thick AL. The TiOx/Au-based GMR structure compensates for the reduced AL thickness, achieving a remarkably high QE (>70%) from 400 to 1700 nm with only a 0.98 μm AL InGaAs PD (defined as 1 μm AL PD). This represents a reduction in thickness by at least 2.5 times compared to previous results while maintaining a high QE. Furthermore, the rapid transit time is highly expected to result in decreased electrical crosstalk. The effectiveness of the GMR structure is evident in its ability to sustain QE even with a reduced AL thickness, simultaneously enhancing the transit time. This breakthrough offers a viable solution for high-resolution and low-noise broadband image sensors.

Impact of CaO-Modified γ-Al2O3 Support on CO Oxidation Activity of Pt/LaFeO3 Catalyst.

In this study, we prepared Pt/29.3 wt % LaFeO3 on a commercial carrier of γ-Al2O3 by inserting a CaO interlayer between LaFeO3 and γ-Al2O3 (i.e., Pt/LaFeO3/CaO/γ-Al2O3) via atomic layer deposition. With the interaction between CaO and LaFeO3, the Pt supported on LaFeO3/CaO/γ-Al2O3 demonstrated diverse dispersion characteristics, with regions showing well-dispersed Pt particles of approximately 2 nm, while others displayed some larger Pt nanoparticles. Interestingly, after redox treatments, the CO adsorption over Pt/LaFeO3/CaO/γ-Al2O3 was significantly attenuated, and high-resolution transmission electron microscope analysis on the Pt surface revealed the presence of FeOx layers covering the Pt. Postoxidation, a thick FeOx layer was generated on Pt, leading to the inertness of the catalyst toward CO oxidation. However, after reduction, a thinner FeOx layer (approximately two atomic layers) developed on Pt, which facilitated the oxidation of CO through the Pt-FeOx interface.

Influence of Nitrogen Content on the Microstructure Evolution and Oxidation Resistance toward Ambient Air of CrAlSiN Coatings Deposited by FCVAD Technique.

In this study, CrAlSiN coatings with nitrogen contents ranging from approximately 42 to 54 at. % were deposited and subsequently exposed to temperatures of 700 or 900 °C for 2 h in ambient air to investigate the impact of nitrogen content on the microstructure evolution and high-temperature oxidation resistance. It was found that the CrAlSiN coating with nitrogen content of 42-45 at. % exhibited an amorphous/nanocrystalline hybrid structure, comprising pure metallic Cr and (Al,Cr)N phases within the matrix, as determined by the TEM, XRD, and XPS analysis. In contrast, as the nitrogen content exceeded 52 at. %, the coatings transformed to a dominantly columnar structure featuring solely Cr(Al)N phase. The CrAlSiN coating with a nitrogen content of ∼52 at. % retained amorphous fraction of around 20% but demonstrated superior oxidation resistance with the lowest parabolic rate constant of 1.1 × 10-14 cm2/s at 900 °C compared to other coatings. This enhanced performance was primarily attributed to the high stability of Cr(Al)N phase and formation of a fine-columnar/amorphous microstructure devoid of metallic Cr, resulting in a significantly thin (∼60 nm) yet dense Al2O3-rich monolayer atop the coating surface during the oxidation. Conversely, substoichiometric CrAlSiN coatings with N content ≤45 at. % would form a thick Cr2O3 outer layer over an underlying Al2O3 layer. Additionally, elemental segregation of Cr, Si, and Al was observed in all CrAlSiN coatings after exposure to 900 °C for 2 h, which was induced by the spinodal decomposition of the ternary nitride phases.

Spatio-temporal variations of the heat fluxes at the ice-ocean interface in the Bohai Sea

Thermodynamic process between the ice and the ocean plays a critical role in the evolution of sea-ice growth and melting in marginal seas. At the ice-ocean interface, the oceanic heat flux and the conductive heat flux transmitted through the ice layer jointly determine the latent heat flux driving the phase change (i.e., ice freezing/melting). In this study, the determination of two important thermal parameters in the ice module of the HAMSOM ice-ocean coupled model, namely the mixed layer thickness and the heat exchange coefficient at the ice-ocean interface, has been adjusted to improve the model performance. Spatio-temporal variations of heat fluxes at the ice-ocean interface in the Bohai Sea are investigated, based on the validated sea ice simulation in the 2011/2012 ice season. The relationships between the interfacial heat fluxes and oceanic and atmospheric conditioning factors are identified. We found that the surface conductive heat flux through ice shows short-term fluctuations corresponding to the atmospheric conditions, the magnitude of these fluctuations decreases with depth in the ice layer, likely due to reduced influence from atmospheric conditions at greater depths. Atmospheric conditions are the key controlling factors of the conductive heat flux through ice, while the oceanic heat flux is mainly controlled by the oceanic conditions (i.e., mixed layer temperature). Spatially, the value of the oceanic heat flux is larger in the marginal ice zone with relatively thin ice than in the inner ice zone with relatively thick ice. In the Bohai Sea, when ice is growing, heat within the ice layer is transferred upward from the ice base, and the heat is losing at the ice-ocean interface. This heat loss in the inner ice zone is obviously greater than that in the marginal ice zone. Whereas when ice is melting, the opposite is true.

Substrate induced composition change during Ge2Sb2Te5 atomic layer deposition and study of initial reactions on SiO2 surface

Ge2Sb2Te5 (GST) is a well-known phase change material used in nonvolatile memory devices, photonics, and nonvolatile displays. This study investigates the impact of precursor sequence during atomic layer deposition (ALD) of GST from GeCl2.C4H8O2, SbCl3, and Te[(CH3)3Si]2 on Si/SiO2 substrates, focusing on growth per cycle, morphology, and composition along with initial precursor reactions on the substrate. We found that while thick layers approach stoichiometric Ge2Sb2Te5, a Ge-rich interfacial layer is initially formed, regardless of the binary ALD sequence used to start the deposition (GeTe vs Sb2Te3). Starting the ALD process with the GeTe-Sb2Te3 sequence results in a higher Ge content near the GST/SiO2 interface compared to the Sb2Te3-GeTe sequence. To understand these phenomena, we examine the initial precursor reactions on the SiO2 substrate by total reflection x-ray fluorescence spectrometry. The analysis reveals that SbCl3 exhibits lower reactivity with the SiO2 substrate than GeCl2.C4H8O2, and not all Ge adspecies react with the Te[(CH3)3Si]2 precursors. Additionally, the impact of the initial SiO2 surface on deposition extends over several ALD cycles, as the SiO2 surface only gradually gets covered by GST due to island growth. These processes contribute to the formation of a Ge-rich GST layer at the interface, irrespective of the precursor pulse sequence. These insights from the study may contribute to optimizing the initial deposition stages of GST and other ternary ALD processes to enable better composition control and enhanced device performance.

Optimization of Laser Based-Powder Bed Fusion Parameters for Controlled Porosity in Titanium Alloy Components

Laser based-powder bed fusion (LB-PBF) enables fast, efficient, and cost-effective production of high-performing products. While advanced functionalities are often derived from geometric complexity, the capability to tailor material properties also offers significant opportunities for technical innovation across many fields. This study explores the optimization of the LB-PBF process parameters for producing Ti6Al4V titanium alloy parts with controlled porosity. To this end, cuboid and lamellar samples were fabricated by systematically varying laser power, hatch distance, and layer thickness according to a full factorial Design of Experiments, and the resulting specimens were thoroughly characterized by analyzing envelope porosity, surface roughness and waviness, surface morphology, and surface area. A selection of specimens was further examined using small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) to investigate the atomic structure and nanometric porosity of the material. The results demonstrated the possibility to finely control the porosity and surface characteristics of Ti6Al4V within specific LB-PBF process ranges. The pores were found to be mostly closed even for thin walls, while the surface roughness was recognized as the primary factor impacting the surface area. The lamellar samples obtained by exposing single scan tracks showed nearly an order-of-magnitude increase in both surface area and pore volume, thereby laying the groundwork for the production of parts with optimized porosity.

Effect of process variables on Ultimaker 2+ 3D FDM printed Tough PLA parts

ABSTRACT Fused Deposition Modeling (FDM) is pivotal in creating functional prototypes and end-use parts, with Tough PLA emerging as a favored material due to its durability. However, fine-tuning printing process variables for Tough PLA on the Ultimaker 2 + 3D printer remains challenging. This study employs Taguchi Grey relational analysis to optimize these process variables. L09 Taguchi’s systematic approach and Taguchi Grey Relational Grade Analysis (TGRGA) investigated Layer Thickness (LT), Infill Density (ID), and Nozzle Temperature (NT) at varying levels for which response variables such as Ultimate Tensile Strength (UTS), Average hardness (AH), and Surface Roughness (Ra) are evaluated. Utilizing Taguchi Grey Relational Grade Analysis (TGRGA), enhancements in ultimate tensile strength from 43.182 N/mm2 to 46.56 N/mm2, average hardness from 64 to 67, and Surface roughness from 8.60 µm to 8.35 µm are achieved. This study contributes to advancing additive manufacturing optimization, offering insights into refining Tough PLA part production on the Ultimaker 2 + 3D printer for bio implants like stent application.

Effect of Surface Pretreatments on the Formation of Zr‐Based Conversion Layers on Zn–Al–Mg Alloy‐Coated Steel

ABSTRACTZr‐based conversion coatings represent an environmentally conscious alternative to traditional phosphating and chromating in the automotive industry. In this study, we employ XPS and LEIS to investigate the formation of Zr‐conversion layers on Zn–Mg–Al alloy after alkaline and acidic model pretreatments. On alkaline pretreated surfaces, a Zr‐oxide/oxyfluoride layer and an underlying Mg–Al–fluoride layer are formed, whereas acidic pretreatment results in only an oxidic layer. The thickness of the Zr‐layer depends on pretreatment pH and immersion time. Acidic treatment achieves an approximately 23 nm‐thick Zr‐oxide/oxyfluoride layer after 1 min, while prolonged treatment increases the thickness of the oxidic layer for strong alkaline and acidic conditions. Mild alkaline pretreatments, however, do not benefit from extended immersion. F‐induced corrosion pits are observed after mild alkaline treatment. The strong alkaline pretreatment proved to be the most efficient in creating a double‐layered Zr‐conversion coating with increased oxidic layer thickness over time.

Earliest location of glaucomatous retinal nerve fibre layer damage is determined by intact baseline RNFL thickness profile

Background/aimsTo identify whether an intact retinal nerve fibre layer (RNFL) thickness profile could determine the location of the earliest RNFL defect in glaucoma.MethodsRetrospective longitudinal cohort study of patients with initial...

Synthesis, Performance Evaluation, and Adsorption-Dispersion Mechanism of Sulfonic Acid-Terminated Long Side Chain Polycarboxylate Superplasticizers.

Polycarboxylate superplasticizers (PCEs) achieve dispersion mainly via steric hindrance from poly(ether) side chains. However, long side chains may cause structural collapse. This study mitigates this issue by introducing sulfonic acid terminations to the long side chains, synthesizing sulfonic-terminated polycarboxylates (PCEPS). Electrostatic repulsion between sulfonic and carboxyl groups on the main chain reduces the level of collapse, enhancing PCE dispersion in cement. PCEPS-4000 showed the strongest dispersion compared with conventional PCEs (PCEC). PCEPS-4000 formed an adsorption layer thickness (ALT) of 11.65 nm, showing a significant improvement over the 7.93 nm observed in the carboxyl-terminated long side chain polycarboxylate (PCETA). Stronger negative charge and lower complexation of sulfonic acid groups enhance the side chain extension. PCEPS also shows good clay tolerance and slump retention, proving its versatility as a concrete admixture.

Correlation of retinal fluid and photoreceptor and RPE loss in neovascular AMD by automated quantification, a real-world FRB! analysis.

To quantify ellipsoid zone (EZ) loss during anti-VEGF therapy for neovascular age-related macular degeneration (nAMD) and correlate these findings with nAMD disease activity using artificial intelligence-based algorithms. Spectral domain optical coherence tomography (Spectralis, Heidelberg Engineering) images from nAMD treatment-naïve patients from the Fight Retinal Blindness! (FRB!) Registry from Zürich, Switzerland were processed at baseline and over 3 years of follow-up. An approved deep learning algorithm (Fluid Monitor, RetInSight) was used to automatically quantify intraretinal fluid (IRF), subretinal fluid (SRF) and pigment epithelial detachment (PED). An ensemble U-net deep learning algorithm was used to automated quantify EZ integrity based on EZ layer thickness. The impact of fluid volumes on EZ thickness and late-stages outcomes were calculated using Wilcoxon rank-sum tests, a linear mixed model and a longitudinal panel regression model. Two hundred and eleven eyes from 158 patients were included. The mean ± SD EZ loss area in the central 6 mm was 1.81 ± 2.68 mm2 at baseline and reached 6.21 ± 6.15 mm2 at month 36. Higher fluid volumes (top 25%) of IRF and PED in the central 1 and 6 mm of the macula were significantly associated with more advanced EZ thinning and loss compared to the low fluid volume subgroup. The high SRF subgroup in the linear regression model showed no statistically significant association with EZ integrity in the central macula; however, the longitudinal analysis revealed an increased EZ thickness with no additional loss. Intraretinal fluid and PED volumes and their resolution pattern have an impact on alteration of the underlying EZ layer. AI-supported quantifications are helpful in quantifying early signs of macular atrophy and providing individual risk profiles as a basis for tailored therapies for optimized visual outcomes.

On the role of local reinforcement in an adhesively bonded AL/CFRP energy absorber under axial loading: A theoretical investigation and optimization

AbstractThis paper aims to develop a novel theoretical model that incorporates the effects of local composite reinforcement using adhesive bonding on the energy absorption of aluminum structures under axial loading. The goal is to optimize energy absorption prior to any connection failures and to prevent uneven structural deformation. Moreover, it strives to reduce the structure's weight and material usage, achieving superior results compared to traditional global reinforcement techniques. The theoretical model was validated through experimental testing and finite element analysis, demonstrating good agreement with the predicted results. The results reveal that increasing the CFRP fiber angle, layer thickness, and number of layers generally leads to improved energy absorption capacity. An optimization analysis was performed to determine the optimal design parameters, yielding a fiber angle of 80°–90°, composite thickness of 1.5 mm, and aluminum thickness of 2.5 is the best configuration, offering the highest specific energy absorption and adequate peak load capacity for maximized energy absorption. The proposed model offers significant improvements over existing approaches, enhancing the predictive capabilities and practical applicability of energy absorption predictions in engineering design.Highlights A novel theoretical model for energy absorption in locally reinforced hybrid AL/CFRP structures. The influence of design parameters, such as CFRP layer count, fiber orientation, and thickness ratio. Optimization to maximize the average crushing force while meeting weight and geometric constraints. Findings can inform the design of safer and more efficient energy‐absorbing structures in various applications.

The Mechanical Properties of Aged PA-12 FS3300PA Powder: Influence of Layer Thickness, Sintering Orientations, and Laser Power

Abstract This research investigates the influence of layer thickness, laser power, and sintering orientation on the mechanical properties of aged Polyamide-12 (PA-12) FS3300PA using the Selective Laser Sintering (SLS) 3D printing method. Specimens were sintered with three different layer thicknesses, laser powers, and sintering orientations using SLS. The study also aimed to examine the resulting powder morphology, mechanical properties, and tensile fracture behaviors of the aged (more than eight continuously sintering cycles) and virgin FS3300PA powders. The specimens divided into ten groups: nine groups of aged powder and one group of virgin powder as a benchmark. The nine groups of aged powder were sintered with three different layer thicknesses (0.07 mm, 0.12 mm, and 0.15 mm), laser powers (65W, 70W, and 75W), and orientations (YZY 0⁰, YZY 90⁰, and XYY 0⁰). The selections of these laser power and layer thickness values for the sintering setting are due to machine and material parameter limitation. The results from these parameters then compared with those of the virgin powder, which sintered using the parameters provided by the manufacturer, in terms of powder morphology, mechanical properties, and tensile fracture behaviours. Observation made using scanning electron microscope (SEM) revealed that there were not many changes in shape, size, and distribution between the virgin and aged powder, but slightly larger sizes and the presence of cracks found in the aged powder. The tensile strength, elongation at break value, and Young’s modulus all shared a similar trend, increasing with higher laser power but decreasing with increased layer thickness. Regarding the fracture morphologies, the number of pores and dimples decreased with increased laser power but increased with thicker layer thickness. There was also the occurrence of un-molten powder, especially in specimens sintered at the YZY 90⁰ orientation with lower laser power and thicker layer thickness.

Machine learning enabled fast optical identification and characterization of 2D materials.

Two-dimensional materials are a class of atomically thin materials with assorted electronic and quantum properties. Accurate identification of layer thickness, especially for a single monolayer, is crucial for their characterization. This characterization process, however, is often time-consuming, requiring highly skilled researchers and expensive equipment like atomic force microscopy. This project aims to streamline the identification process by using machine learning to analyze optical images and quickly determine layer thickness. In this paper, we evaluate the performance of three machine learning models - SegNet, 1D U-Net, and 2D U-Net- in accurately identifying monolayers in microscopic images. Additionally, we explore labeling and image processing techniques to determine the most effective and accessible method for identifying layer thickness in this class of materials.

Atmosphere Effects in Laser Powder Bed Fusion: A Review

The use of components fabricated by laser powder bed fusion (LPBF) requires the development of processing parameters that can produce high-quality material. Manipulating the most commonly identified critical build parameters (e.g., laser power, laser scan speed, and layer thickness) on LPBF equipment can generate acceptable parts for established materials and moderately intricate part geometries. The need to fabricate increasingly complex parts from unique materials drives the limited research into LPBF process control using underutilized parameters, such as atmosphere composition and pressure. As presented in this review, manipulating atmosphere composition and pressure in laser beam welding has been shown to expand processing windows and produce higher-quality welds. The similarities between laser beam welding and laser-based AM processes suggest that this atmosphere control research could be effectively adapted for LPBF, an area that has not been widely explored. Tailoring this research for LPBF has significant potential to reveal novel processing regimes. This review presents the current state of the art in atmosphere research for laser beam welding and LPBF, with a focus on studies exploring cover gas composition and pressure, and concludes with an outlook on future LPBF atmosphere control systems.

Adaptation of the small intestine mucosa after gastric bypass surgery with a single anastomosis

Objective. To compare the morphological and morphometric changes of the small intestine mucosa in its common and biliopancreatic loops at different times after gastric bypass surgery with a single anastomosis. Materials and methods. The study included 36 patients who received surgical treatment at the Department of Thoracoabdominal Surgery of the Shalimov National Research Center for Surgery and Transplantation of the National Academy of Medical Sciences of Ukraine for morbid obesity, which consisted of gastric bypass surgery with a single anastomosis in various variants (long–loop, distal, mini–gastric bypass) in the period from 2016 to 2022. Further outpatient follow–up included scheduled endoscopic examinations at 3, 12, and 24 months after surgery. Results. At 3 months after the operation, no morphological and morphometric changes were detected in the studied biopsies of the mucous membrane of the biliopancreatic and common loops of the small intestine. The first morphological and morphometric changes in the small intestinal mucosa were observed 12 months after surgery. There was a statistically significant (p &lt; 0.05) difference in the length of intestinal villi in the common and biliopancreatic loops of the small intestine – (0.390 ± 0.199) and (0.377 ± 0.184) mm, respectively. These changes indicate hypertrophy of villi in the colon to increase the absorption area. The thickness of the basal layer was greater in the biliopancreatic loop than in the total loop and amounted to (0.196 ± 0.068) and (0.167 ± 0.043) mm, respectively (p &gt; 0.05). There was no statistically significant difference between the number of crypts containing Paneth cells in the biliopancreatic and common loops, so the regulatory function of these cells was preserved in any variant of gastric bypass with a single anastomosis. Conclusions. Morphological and morphometric changes in the small intestinal mucosa after gastric bypass with a single anastomosis may be associated with various physiological conditions and have clinical significance for understanding the mechanisms of absorption and intestinal protection. Additional studies with a larger number of samples and the use of modern methods of morphological analysis are needed to deepen the understanding of these processes.

Influence of Ultrasonic Surface Rolling on the Tensile and Fatigue Properties of Laser-Cladding-Repaired 300M Steel Components

Abstract Herein, to address the issue of decreased tensile and fatigue performances observed in 300M steel scratched parts after laser-cladding repairing, an ultrasonic surface rolling process (USRP) was employed to enhance the strength of the laser-cladding-repaired (LCR) samples. Results indicated that USRP led to the formation of a strengthening layer on the surface of the samples. In the parent material area, the thickness of the strengthening layer was 180 μm, while in the cladding area, it was 35 μm. The superficial microhardness increased by 11.6% in the parent material area and by 5.0% in the cladding area. Furthermore, the surface residual stress transitioned from tensile to compressive stress, reaching a maximum of 1169.9 MPa. Improvements were observed in the tensile performance, as evidenced by a reduction in the length of the tearing ridge in the fracture morphology. In addition, the fatigue life considerably increased, initially increasing and then decreasing as the number of rolling passes increased. After four cycles of USRP, the fatigue life of the samples was the highest, which was about 18.4 times that of an unprocessed sample. The origin location of cracks shifted from the surface to the interior of the samples. This shift was accompanied by a decrease in the instantaneous fracture area and the emergence of additional secondary cracks. These experimental results demonstrate that USRP is an effective technique for improving the tensile and fatigue performances of LCR 300M steel samples.