Mechanical behavior and response mechanism of porous metal structures manufactured by laser powder bed fusion under compressive loading

Al Si10Mg porous protective structure often produces different damage forms under compressive loading,and these damage modes affect its protective function.In order to well meet the service requirements,there is an urgent need to comprehensively understand the mechanical behavior and response mechanism of AlSi10Mg porous structures under compressive loading.In this paper,Al Si10Mg porous structures with three kinds of volume fractions are designed and optimized to meet the requirements of high-impact,strong-energy absorption,and lightweight characteristics.The mechanical behaviors of AlSi10Mg porous structures,including the stress-strain relationship,structural bearing state,deformation and damage modes,and energy absorption characteristics,were obtained through experimental studies at different loading rates.The damage pattern of the damage section indicates that AlSi10Mg porous structures have both ductile and brittle mechanical properties.Numerical simulation studies show that the AlSi10Mg porous structure undergoes shear damage due to relative misalignment along the diagonal cross-section,and the damage location is almost at 45°to the load direction,which is the most direct cause of its structural damage,revealing the damage mechanism of AlSi10Mg porous structures under the compressive load.The normalized energy absorption model constructed in the paper well interprets the energy absorption state of Al Si10Mg porous structures and gives the sensitive location of the structures,and the results of this paper provide important references for peers in structural design and optimization.

Application of exosomal miRNA mediated macrophage polarization in colorectal cancer:Current progress and challenges

Colorectal cancer(CRC)is a major global health problem with high morbidity and mortality rates.Surgical resection is the main treatment for early-stage CRC,but detecting it early is challenging.Therefore,effective therapeutic targets for advanced patients are still lacking.Exosomes,tiny vesicles in body fluids,play a crucial role in tumor metastasis,immune regulation,and drug resistance.Interestingly,they can even serve as a biomarker for cancer diagnosis and prognosis.Studies have shown that exosomes can carry miRNA,mediate the polarization of M1/M2 macrophages,promote the proliferation and metastasis of cancer cells,and affect the prognosis of CRC.Since the gastrointestinal tract has many macrophages,understanding the mechanism behind exosomal miRNA-mediated macrophage polarization in CRC treatment is crucial.This article summarizes recent advancements in the study of exosomal miRNAs in CRC and their potential as diagnostic and prognostic markers.

Lateral patellofemoral ligament reconstruction to restore functional capacity in patients previously undergoing lateral retinacular release

AIM: To study patient outcomes after surgical correction for iatrogenic patellar instability.METHODS: This retrospective study looked at 17 patients(19 knees) suffering from disabling medial patellar instability following lateral release surgery. All patients underwent lateral patellofemoral ligament(LPFL) reconstruction by a single surgeon. Assessments in all 19 cases included functional outcome scores, range of motion, and assessment for the presence of apprehension sign of the patella to determine if LPFL reconstruction surgery was successful at restoring patellofemoral stability.RESULTS: No patients reported any residual postoperative symptoms of patellar instability. Also no patients demonstrated medial patellar apprehension or examiner induced subluxation with the medial instability test described earlier following LPFL reconstruction. Furthermore, all patients recovered normal range of motion compared to the contralateral limb. For patients with pre and postoperative outcome scores, the mean overall knee injury and osteoarthritis outcome score increased significantly, from 34.39 preoperatively(range: 7.7-70.12) to 69.54 postoperatively(range:26.82-91.46) at final follow-up(P < 0.0001). CONCLUSION: This novel technique for LPFL reconstruction is effective at restoring lateral restraint of the patellofemoral joint and improving joint functionality.

Mechanical characterization of a 10-MJ HTS SMES magnet wound by quasiisotropic strands and directly stacked tape conductors

A 10‐MJ‐class superconducting magnetic energy storage(SMES)magnet is designed and optimized in this study using quasi‐isotropic strands and stacked‐tape conductors.In order to ensure the stable operation of SMES systems,it is necessary to evaluate the mechanical properties risk caused by the Lorentz force.Therefore,in this study,the magnetic stress caused by the Lorentz force is analyzed using the finite element method.The results show that the tapes near the inner diameter of the magnet are subjected to a higher stress and require considerable support.Although the maximum stress is increased by two times due to the presence of the screening current,it is within the safety range.The screening current does not vanish after the discharge process.After discharge,the coil is still subjected to a stress on the other of a few MPa.