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<p>InP/ZnS Quantum Dots Cause Inflammatory Response in Macrophages Through Endoplasmic Reticulum Stress and Oxidative stress</p>
摘要： Quantum dots (QDs) are widely used semiconductor nanomaterials. Indium phosphide/zinc sulfide (InP/ZnS) QDs are becoming potential alternatives to toxic heavy metal-containing QDs. However, the potential toxicity and, in particular, the immunotoxicity of InP/ZnS QDs are unknown. This study aimed to investigate the impacts of InP/ZnS QDs on inflammatory responses both in vivo and in vitro. Methods: Mice and mouse bone marrow-derived macrophages (BMMs) were exposed to polyethylene glycol (PEG) coated InP/ZnS QDs. The infiltration of neutrophils and the release of interleukin-6 (IL-6) were measured using a hematology analyzer and an enzyme-linked immunosorbent assay (ELISA) for the in vivo test. Cytotoxicity, IL-6 secretion, oxidative stress and endoplasmic reticulum (ER) stress were studied in the BMMs, and then, inhibitors of oxidative stress and ER stress were used to explore the mechanism of the InP/ZnS QDs. Results: We found that 20 mg/kg PEG-InP/ZnS QDs increased the number of neutrophils and the levels of IL-6 in both peritoneal lavage fluids and blood, which indicated acute phase inflammation in the mice. PEG-InP/ZnS QDs also activated the BMMs and increased the production of IL-6. In addition, PEG-InP/ZnS QDs triggered oxidative stress and the ER stress-related PERK-ATF4 pathway in the BMMs. Moreover, the inflammatory response caused by the PEG-InP/ZnS QDs could be attenuated in the macrophages by blocking the oxidative stress or the ER stress with inhibitors. Conclusion: InP/ZnS QDs can activate macrophages and induce acute phase inflammation both in vivo and in vitro, which may be regulated by oxidative stress and ER stress. Our present work is expected to help clarify the biosafety of InP/ZnS QDs and promote their safe application in biomedical and engineering fields.
关键词： indium phosphide,inflammation,endoplasmic reticulum stress,quantum dots,reactive oxygen species
更新于2025-09-16 10:30:52
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Efficacy of the Use of Fractional CO2RE Intima Laser Treatment in Stress and Mixed Urinary Incontinence
摘要： Objective: The objective of this clinical study was to evaluate the efficacy of a vaginal CO2 laser treatment (CO2RE Intima) in patients with moderate, severe and very severe stress urinary incontinence (SUI) or mixed urinary incontinence (MUI), as well as its impact in sexual relations. Design: This was a single-center, prospective, interventional study that included 25 women aged 35-68 years who presented with moderate, severe and very severe symptoms of SUI or MUI, based on Sandvik index and ICIQ-UI scores. A series of three fractional micro-ablative CO2 laser treatment sessions was performed, each spaced 4 to 6 weeks apart. Improvements were measured and evaluated using scores from validated questionnaires including the International Consultation on Incontinence Questionnaire (ICIQ-IU), the Sandvik severity index, and the Female Sexual Function Index (FSFI). Adverse events were recorded throughout the study and assessed using the Common Side Effect Questionnaire that evaluates pain, hemorrhage, burn, bruising and edema. Results: CO2RE intima laser treatment resulted in a significant improvement (P<0.001) in the scores of both the ICIQ-UI questionnaire and the Sandvik index, after the 2nd session; and this significance persisted after the 3rd treatment session. Improvements in UI severity was also achieved; after the 1st laser treatment, a significant improvement in severity was seen (p< 0.01), the significance of which showed to increase after the 2nd and 3rd treatment sessions (p<0.001). Improvement related to the type of UI measured with the ICIQ questionnaire was significant in both cases with SUI (p=0.035) and MUI (p<0.001) after the second treatment. This difference persisted after the 3rd treatment in cases of MUI and the trend, though not the statistical significance, persisted in SUI cases, (p=0.197). Improvement in severity was significant in both SUI and MUI types, from the first treatment to the end of the study. Sexual function of patients as reflected in the FSFI questionnaire scores also showed to improve; the difference was significant after the second session (p=0.013) and persisted at the end of the study (p= 0.047). Conclusion: Fractional, micro-ablative CO2RE Intima laser treatment is a minimally invasive procedure that can significantly improve moderate and severe SUI and MUI. It also improves sexual function in women with these types of incontinence. Though our positive results are promising, this preliminary data must be confirmed with other studies.
关键词： CO2RE Intima laser,moderate and severe stress urinary incontinence,mixed urinary incontinence
更新于2025-09-16 10:30:52
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Fatigue Behaviour of Laser Spot Welds in Dual Phase 780 Steel
摘要： High cycle fatigue performance was evaluated on circular shaped laser spot welds (LSW) of dual phase DP780 steels. Fibre laser with two different parameter sets were applied to produce the spot welds. The weld size growth is concomitant to laser power. The failure mechanism under fatigue loading, involving crack initiation and propagation till failure, is explained using analytical stress models and experimental data. Interrupted fatigue tests were done and the crack path was captured by observing under scanning electron microscope. Stress models show that during tensile shear loading of overlapping sheets having spot weld, there is a countering effect of shear stress and bending stress; the latter acts perpendicular to the shear stress and arises from the bending moment along the plane of contact during load transfer. The dominant stress depends on the contact area, i.e. the weld size, which largely controls the crack path route and concurrent fatigue life. Incidentally smaller welds show marginally longer life wherein the stronger axial stress component propels the crack through a longer route consuming more number of cycles. Again, with lowering of fatigue load there is a shift in the mode of failure with transition from interfacial to partial to pull-out failure. However, large welds fail in pull-out mode only irrespective of the fatigue load levels. As compared to the size effect, the weld microstructure has less influence on fatigue crack propagation.
关键词： Laser welding,Stress Intensity Factor,High Cycle Fatigue behaviour,Circular weld,Dual phase steel
更新于2025-09-16 10:30:52
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Residual stress in laser cladded heavy-haul rails investigated by neutron diffraction
摘要： Residual stress is one of the critical parameters affecting the fatigue behaviour of tribological components, which can be introduced by a thermo-mechanical process such as laser cladding. In this study, the residual stress distribution of laser cladded rails was evaluated using a neutron diffraction technique. The substrate rail for the laser cladding was hypereutectoid rail steel used in Australian heavy-haul railway track, and the cladding materials were 410L (a low carbon content stainless steel alloy) and Stellite 6 (a Co-based alloy). The cladding materials were selected based on their high wear, corrosion and fatigue resistance properties. This study measured the residual stress in full-scale laser cladded rails where the residual stresses were measured in the cladding layer, heat affected zone (HAZ) and substrate zone of the railhead. A new sample preparation strategy was developed to quantify the residual stresses in the full-scale rails with high spatial resolution. Higher compressive residual stress was found in the cladding layer, which may have resulted from the martensitic transformation occurred in that region. Tensile stresses occurred in the HAZ to a depth of 4 mm, which might be mainly caused by thermal contraction and volumetric change in the microstructure. The addition of a second cladding layer did not significantly affect the magnitude of the residual stresses, but the peak tensile residual stress shifted to a deeper location from the surface, which is beneficial in resisting wear. Post-cladding heat treatment significantly reduced the undesirable high residual stress from the cladding layer and HAZ.
关键词： Post-cladding heat treatment,Residual stress,Neutron diffraction,Laser cladding,Heavy-haul rail
更新于2025-09-16 10:30:52
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Graphene Quantum Dots Induce Autophagy and Reveal Protection Against Hydrogen Peroxide-Induced Oxidative Stress Injury
摘要： As the zero-dimension nanomaterials, graphene quantum dots (GQDs) have excellent characteristics of graphene as well as photoluminescence (PL) features that ordinary graphene does not possess for its virtue of quantum confinement effect and boundary effect, and attract lots of researchers interested in the field of biomedical applications. In this work, we found GQDs can be internalized into SGC-7901 cells, and the labeled cells exhibited bright yellow fluorescence in the form of aggregated dots. Meanwhile, GQDs effectively mitigated the injury hydrogen peroxide (H2O2)-induced in SGC-7901 cells including cytotoxicity and apoptosis. While H2O2 exposure increased ROS and decreased mitochondrial membrane potential, it could be arrested by GQDs. Furthermore, GQDs showed protective effects against the reduction of the ratio of mitochondrial apoptosis-related proteins Bcl-2/ Bax in SGC-7901 cells. Our works revealed that GQDs had the antioxidant ability against oxidative stress, which meant they had the potential to be an antioxidants. Besides, GQDs increased the level of autophagy-related protein LC3-II and induced autophagic structure observed via TEM, and subsequent the results of LC3 turnover and p62 degradation demonstrated GQDs treatment led to the activation of autophagic flux. Ultimately, GQDs were found to affect autophagy through the mTOR signaling pathway.
关键词： graphene quantum dots,apoptosis,antioxidant,oxidative stress,autophagy
更新于2025-09-16 10:30:52
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Toxicity Evaluation of Quantum Dots (ZnS and CdS) Singly and Combined in Zebrafish (Danio rerio)
摘要： The exponential growth of nanotechnology has led to the production of large quantities of nanomaterials for numerous industrial, technological, agricultural, environmental, food and many other applications. However, this huge production has raised growing concerns about the adverse effects that the release of these nanomaterials may have on the environment and on living organisms. Regarding the effects of QDs on aquatic organisms, existing data is scarce and often contradictory. Thus, more information is needed to understand the mechanisms associated with the potential toxicity of these nanomaterials in the aquatic environment. The toxicity of QDs (ZnS and CdS) was evaluated in the freshwater fish Danio rerio. The fishes were exposed for seven days to different concentrations of QDs (10, 100 and 1000 μg/L) individually and combined. Oxidative stress enzymes (catalase, superoxide dismutase and glutathione S-transferase), lipid peroxidation, HSP70 and total ubiquitin were assessed. In general, results suggest low to moderate toxicity as shown by the increase in catalase activity and lipid peroxidation levels. The QDs (ZnS and CdS) appear to cause more adverse effects singly than when tested combined. However, LPO results suggest that exposure to CdS singly caused more oxidative stress in zebrafish than ZnS or when the two QDs were tested combined. Levels of Zn and Cd measured in fish tissues indicate that both elements were bioaccumulated by fish and the concentrations increased in tissues according to the concentrations tested. The increase in HSP70 measured in fish exposed to 100 μg ZnS-QDs/L may be associated with high levels of Zn determined in fish tissues. No significant changes were detected for total ubiquitin. More experiments should be performed to fully understand the effects of QDs exposure to aquatic biota.
关键词： oxidative stress,CdS,toxicity,quantum dots,zebrafish,ZnS
更新于2025-09-16 10:30:52
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Method of Reducing Residual Stress Generated by Laser Cutting by Light Indentation of Sheet Metal Edge
摘要： The aim of the present research is to propose a new method for the reduction of the residual stress which was generated by laser cutting. Laser cutting has been expected to be used as an effective and potent method for cutting out blanks from rolled sheet metals because of its high flexibility of the cutting line and high productivity. However, residual stresses, which are inevitably generated by laser cutting, have been the greatest obstacle to the prevalence of laser cutting. One of the problems is the warping that occurs in the sheet metal subjected to bending processes following laser cutting. The authors present a new method for reducing residual stress generated by laser cutting. The method involves applying is to give light indentation on the sheet metal edge. The FEM analyses were carried out to study the feasibility of this method, to determine the method of applying indentation, and to optimize the conditions. Experiments were conducted for verification. As a result, the warp generated by the residual stress was significantly reduced to one-tenth of that without the new treatment, and the magnitude was satisfactorily small for industrial usage.
关键词： laser cutting,longitudinal camber,V bending,blank sheet metal,residual stress
更新于2025-09-16 10:30:52
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Experimental observation of stress formation during selective laser melting using in situ X-ray diffraction
摘要： Despite the ongoing success of metal additive manufacturing and especially the selective laser melting (SLM) technology, process-related defects, distortions and residual stresses impede its usability for fracture-critical applications. In this paper, results of in situ X-ray diffraction experiments are presented that offer insights into the strain and stress formation during the manufacturing of multi-layer thin walls made from Inconel 625. Using different measuring modes and laser scanning parameters, several experimental observations are discussed to validate and extend theoretical models and simulations from the literature. As a sample is built-up layer by layer, the stress state changes continuously up until the last exposure. The localized energy input leads to a complex stress field around the heat source that involves alternating tensile and compressive stresses. The correlation of temperature and yield strength results in a stress maximum at a certain distance to the top layer. The present study demonstrates the potential of high-energy synchrotron radiation diffraction for in situ SLM research.
关键词： Inconel 625,Selective laser melting,Stress formation,In situ,High energy synchrotron radiation diffraction
更新于2025-09-16 10:30:52
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Effect of Laser Shock Peening on Fatigue Life at Stress Raiser Regions of a High-Speed Micro Gas Turbine Shaft: A Simulation Based Study
摘要： Fatigue failure due to stress raiser regions on critical rotating components in gas turbine engines, such as the shaft, is a crucial aspect. Methods to reduce these stresses and improve fatigue life are a source of ongoing research. Laser shock peening is a method where compressive residual stresses are imparted on the stress raisers of such components. However, numerical based studies on multiple laser shock peening applied to stress raisers is under-researched. Hence, this study will attempt to predict the fatigue life at fillet radii step induced stress raiser regions on a high-speed gas turbine engine shaft by utilization of laser shock peening. The objective of this study was achieved by developing a more computational efficient finite element model to mimic the laser shock peening process on the fillet radii step induced stress raiser regions of a shaft. A modified laser shock peening simulation method for effective prediction of the residual stress field was introduced. Furthermore, the fatigue life improvement due to laser shock peening was predicted by employing Fe-safe fatigue software. From the results, the modified laser shock peening simulation method provided accurate prediction of the residual stress field with a reduced computational time of over 68% compared to conventional methods. The fatigue life revealed an improvement of 553% due to laser shock peening, which is comparable to similar findings in the literature. Hence, from the findings and results achieved, the developed finite element model can be an appropriate tool to assist in the fatigue life estimation of laser shock peening applied to stress raisers.
关键词： Fatigue,laser shock peening,Fe-safe software,stress raiser regions,finite element model
更新于2025-09-16 10:30:52
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Device Structure and Passivation Options for the Integration of Scaled IGZO TFTs
摘要： The focus of this work is on the performance dependence of scaled the device structure and IGZO TFTs with variations semiconductor passivation scheme. TCAD simulation was used to provide insight on the details which establish the limits on electrostatic control. Dielectrics used for the gate and back-channel regions have been adjusted to overcome short-channel effects, along with required modifications in process recipes for PECVD passivation layers, oxygen ambient annealing, and ALD capping material. Scaled devices with channel lengths as small as L = 1 μm have been investigated and evaluated by the electrostatic behavior, and stability when subjected to thermal and bias stress. An optimized process and associated procedural details for scaled devices is presented, along with suggested options for further channel length reduction to submicron dimensions.
关键词： IGZO TFTs,scaling,TCAD simulation,electrostatic control,PECVD,short-channel effects,ALD,thermal stability,bias stress,passivation
更新于2025-09-16 10:30:52