Background:Zearalenone(ZEA)is a resorcylic acid lactone derivative derived from various Fusarium species that are widely found in food and feeds.The molecular structure of ZEA resembles that of the mammalian hormone 1...Background:Zearalenone(ZEA)is a resorcylic acid lactone derivative derived from various Fusarium species that are widely found in food and feeds.The molecular structure of ZEA resembles that of the mammalian hormone 17β-oestradiol,thus zearalenone and its metabolites are known to compete with endogenous hormones for estrogen receptors binding sites and to activate transcription of oestrogen-responsive genes.However,the effect of long-term low-dose ZEA exposure on the reproductive response to Bacillus subtilis ANSB01G culture for first-parity gilts has not yet been investigated.This study was conducted to investigate the toxic effects of ZEA as an estrogen receptor selective modulator and the alleviating effects of Bacillus subtilis ANSB01G cultures as ZEA biodegraders in pregnant sows during their first parity.Results:A total of 80 first-parity gilts(Yorkshire×Landrace)were randomly assigned to four dietary treatments during gestation:CO(positive control);MO(negative control,246μg ZEA/kg diet);COA(CO+B.subtilis ANSB01G culture with 2×10^(9)CFU/kg diet);MOA(MO+B.subtilis ANSB01G culture with 2×10^(9)CFU/kg diet).There were 20 replications per treatment with one gilt per replicate.Feeding low-dose ZEA naturally contaminated diets disordered most of reproductive hormones secretion and affected estrogen receptor-αand estrogen receptor-βconcentrations in serum and specific organs and led to moderate histopathological changes of gilts,but did not cause significant detrimental effects on reproductive performance.The addition of Bacillus subtilis ANSB01G culture to the diet can effectively relieve the competence of ZEA to estrogen receptor and the disturbance of reproductive hormones secretion,and then ameliorate toxicosis of ZEA in gilts.Conclusions:Collectively,our study investigated the effects of feeding low-dose ZEA on reproduction in pregnant sows during their first parity.Feeding low-dose ZEA could modulate estrogen receptor-αand-βconcentrations in specific organs,cause disturbance of reproductive hormones and vulva swelling,and damage organ histopathology and up-regulate apoptosis in sow models.Diet with Bacillus subtilis ANSB01G alleviated negative effects of the ZEA on gilts to some extent.展开更多
Crude and used engine oil degrading ability of two white rot fungi Pleurotus ostreatus and P. pulmonarius were investigated for six months. One hundred grams of sterilized soil moistened with 75% distilled water (w/v)...Crude and used engine oil degrading ability of two white rot fungi Pleurotus ostreatus and P. pulmonarius were investigated for six months. One hundred grams of sterilized soil moistened with 75% distilled water (w/v) were weighed into 9 × 9 × 4 cm (350 cm3) jam bottles and mixed thoroughly with bonny light crude oil and used engine oil at different concentrations (0%, 5%, 10%, 15%, 25% and 30%), separately. Each bottle was then inoculated with two agar plugs of a vigorously grown mycelium of P. ostreatus and P. pulmonarius using a sterile cork borer. The bottles were incubated at room temperature for 6 months. The mycelia-ramified waste was separated from soils and analysed for physicochemical parameters such as organic matter, carbon, nitrogen, phosphorus, potassium, pH and total hydrocarbon content, (THC) after drying. The organic carbon, nitrogen and phosphorus contents in contaminated and inoculated soils were increased after six months. However, decrease in potassium, pH and THC occurred in these soils after the period of investigation. P. ostreatus reduced the initial THC to 8% and 9% in soils contaminated with 20% of crude and engine oils, respectively, which was lower than that of P. pulmonarius. The two white rot fungi could be exploited in bioremediation of soils contaminated with bonny light crude and used engine oils.展开更多
Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fu...Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.展开更多
Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body environment.This necessitates the synthesis of a suitable coating that may improve ...Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body environment.This necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical integrity.In this study,an AZ91 magnesium alloy,as a representative for a biodegradable Mg implant material,was modified with a thin reduced graphene oxide(RGO)-calcium carbonate(CaCO_(3))composite coating.Detailed analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field.展开更多
●AIM:To compare the success rate and complications of adjuvant use of mitomycin C and triamcinoloneimpregnated biodegradable nasal packing(TABP)in endoscopic dacryocystorhinostomy(DCR).And to evaluate the efficacy of...●AIM:To compare the success rate and complications of adjuvant use of mitomycin C and triamcinoloneimpregnated biodegradable nasal packing(TABP)in endoscopic dacryocystorhinostomy(DCR).And to evaluate the efficacy of combining intraoperative mitomycin C and TABP for endoscopic DCR.●METHODS:A total of 198 eyes of 148 patients who underwent endoscopic DCR for acquired nasolacrimal duct obstruction were retrospectively analysed.The patients were randomly divided into three groups:Group A included patients treated without intraoperative mitomycin C but with TABP,Group B included patients treated without triamcinolone but with intraoperative mitomycin C and normal saline-impregnated nasal packing,and Group C included patients treated with intraoperative mitomycin C and TABP.●RESULTS:The results revealed no significant difference in the overall success rates between Groups A(86.8%)and B(89.2%;P=0.377).However,Group C(97.5%)showed a significantly higher overall success rate than Groups A and B.The incidence of granulomas was significantly lower in group C(5%)than in Groups A(20.8%)and B(15.2%;P=0.009).Other complications,such as crust,synechiae,and revision surgery,did not differ significantly among the three groups.●CONCLUSION:The combination of intraoperative mitomycin C and TABP effectively prevents granulomas and enhances surgical success rate.Additionally,there is no statistically significant difference observed between the use of mitomycin C or TABP alone.展开更多
Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machi...Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.展开更多
The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human ...The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.展开更多
Substrates or encapsulants in soft and stretchable formats are key components for transient,bioresorbable electronic systems;however,elastomeric polymers with desired mechanical and biochemical properties are very lim...Substrates or encapsulants in soft and stretchable formats are key components for transient,bioresorbable electronic systems;however,elastomeric polymers with desired mechanical and biochemical properties are very limited compared to nontransient counterparts.Here,we introduce a bioresorbable elastomer,poly(glycolide-co-ε-caprolactone)(PGCL),that contains excellent material properties including high elongation-at-break(<1300%),resilience and toughness,and tunable dissolution behaviors.Exploitation of PGCLs as polymer matrices,in combination with conducing polymers,yields stretchable,conductive composites for degradable interconnects,sensors,and actuators,which can reliably function under external strains.Integration of device components with wireless modules demonstrates elastic,transient electronic suture system with on-demand drug delivery for rapid recovery of postsurgical wounds in soft,time-dynamic tissues.展开更多
Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong disability.Currently,there are no FDA-approved therapies a...Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong disability.Currently,there are no FDA-approved therapies available to promote nerve regeneration.Tacrolimus accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve surgery.The authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug exposure.Tacrolimus is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 days.Size and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible byproducts.Tacrolimus released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic delivery.Given its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.展开更多
Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,wit...Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.展开更多
The cardiovascular diseases(CVD)continue to be the major threat to global public health over the years,while one of the effective methods to treat CVD is stent intervention.Biomedical magnesium(Mg)alloys have great po...The cardiovascular diseases(CVD)continue to be the major threat to global public health over the years,while one of the effective methods to treat CVD is stent intervention.Biomedical magnesium(Mg)alloys have great potential applications in cardiovascular stents benefit from their excellent biodegradability and absorbability.However,excessive degradation rate and the delayed surface endothelialization still limit their further application.In this study,we modified a Mg-Zn-Y-Nd alloy(ZE21B)by preparing MgF_(2) as the corrosion resistance layer,the dopamine polymer film(PDA)as the bonding layer,and hyaluronic acid(HA)loaded astaxanthin(ASTA)as an important layer to directing the cardiovascular cells fate.The electrochemical test results showed that the MgF_(2)/PDA/HA-ASTA coating improved the corrosion resistance of ZE21B.The cytocompatibility experiments also demonstrated that this novel composite coating also selectively promoted endothelial cells proliferation,inhibited hyperproliferation of smooth muscle cells and adhesion of macrophages.Compared with the HAloaded rapamycin(RAPA)coating,our MgF_(2)/PDA/HA-ASTA coating showed better blood compatibility and cytocompatibility,indicating stronger multi-functions for the ZE21B alloy on cardiovascular application.展开更多
Magnesium(Mg)alloys are considered to be a new generation of revolutionary medical metals.Laser-beam powder bed fusion(PBF-LB)is suitable for fabricating metal implants withpersonalized and complicated structures.Howe...Magnesium(Mg)alloys are considered to be a new generation of revolutionary medical metals.Laser-beam powder bed fusion(PBF-LB)is suitable for fabricating metal implants withpersonalized and complicated structures.However,the as-built part usually exhibits undesirable microstructure and unsatisfactory performance.In this work,WE43 parts were firstly fabricated by PBF-LB and then subjected to heat treatment.Although a high densification rate of 99.91%was achieved using suitable processes,the as-built parts exhibited anisotropic and layeredmicrostructure with heterogeneously precipitated Nd-rich intermetallic.After heat treatment,fine and nano-scaled Mg24Y5particles were precipitated.Meanwhile,theα-Mg grainsunderwent recrystallization and turned coarsened slightly,which effectively weakened thetexture intensity and reduced the anisotropy.As a consequence,the yield strength and ultimate tensile strength were significantly improved to(250.2±3.5)MPa and(312±3.7)MPa,respectively,while the elongation was still maintained at a high level of 15.2%.Furthermore,the homogenized microstructure reduced the tendency of localized corrosion and favoredthe development of uniform passivation film.Thus,the degradation rate of WE43 parts was decreased by an order of magnitude.Besides,in-vitro cell experiments proved their favorable biocompatibility.展开更多
UHP Mg-Ge alloys was recently found to provide excellent corrosion resistance.This paper provides new insights on the mechanism of improved corrosion resistance of UHP Mg-Ge alloys in Hanks’solution.The studied UHP M...UHP Mg-Ge alloys was recently found to provide excellent corrosion resistance.This paper provides new insights on the mechanism of improved corrosion resistance of UHP Mg-Ge alloys in Hanks’solution.The studied UHP Mg-0.5Ge and UHP Mg-1Ge alloys showed superior corrosion resistance compared to UHP Mg and WE43,with the Mg-1Ge exhibiting the best corrosion performance.The exceptional corrosion resistance of the UHP alloy is attributed to(i)Mg_(2)Ge’s ability to suppress cathodic kinetics,(ii)Ge’s capability to accelerate the formation of a highly passive layer,and the(iii)low amounts of corrosion-accelerating impurities.展开更多
In recent years,a great deal of attention has been focused on the environmental impact of plastics,includ-ing the carbon emissions related to plastics,which has promoted the application of biodegradable plas-tics.Coun...In recent years,a great deal of attention has been focused on the environmental impact of plastics,includ-ing the carbon emissions related to plastics,which has promoted the application of biodegradable plas-tics.Countries worldwide have shown high interest in replacing traditional plastics with biodegradable plastics.However,no systematic comparison has been conducted on the carbon emissions of biodegrad-able versus traditional plastic products.This study evaluates the carbon emissions of traditional and biodegradable plastic products(BPPs)over four stages and briefly discusses environmental and economic perspectives.Four scenarios-namely,the traditional method,chemical recycling,industrial composting,and anaerobic digestion-are considered for the disposal of waste BPPs(WBPPs).The analysis takes China as a case study.The results show that the carbon emissions of 1000traditional plastic products(plastic bags,lunch boxes,cups,etc.)were52.09-150.36 carbon emissions equivalent of per kilogram(kg CO_(2)eq),with the stage of plastic production contributing 50.71%-50.77%.In comparison,1000 similar BPPs topped out at 21.06-56.86 kg CO_(2)eq,approximately 13.53%-62.19%lower than traditional plastic prod-ucts.The difference was mainly at the stages of plastic production and waste disposal,and the BPPs showed significant carbon reduction potential at the raw material acquisition stage.Waste disposal plays an important role in environmental impact,and composting and anaerobic digestion are considered to be preferable disposal methods for WBPPs.However,the high cost of biodegradable plastics is a challenge for their widespread use.This study has important reference significance for the sustainable development of the biodegradableplastics industry.展开更多
Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples...Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples were built with the relativity density reaching 99.9%.High temperature oxidation was performed on the L-PBF samples in circulating air via various heating temperatures and holding durations.The oxidation and diffusion at the elevated temperature generated a gradient structure composed of an oxide layer at the surface,a transition layer in the middle and the matrix.The oxide layer consisted of rare earth(RE)oxides,and became dense and thick with increasing the holding duration.The matrix was composed ofα-Mg,RE oxides and Mg_(24)RE_(5) precipitates.The precipitates almost disappeared in the transition layer.Enhanced passivation effect was observed in the samples treated by a suitable high temperature oxidation.The original L-PBF samples lost 40%weight after 3-day immersion in Hank’s solution,and broke into fragments after 7-day immersion.The casted and solution treated samples lost roughly half of the weight after 28-day immersion.The high temperature oxidation samples,which were heated at 525℃ for 8 h,kept the structural integrity,and lost only 6.88%weight after 28-day immersion.The substantially improved corrosion resistance was contributed to the gradient structure at the surface.On one hand,the outmost dense layer of RE oxides isolated the corrosive medium;on the other hand,the transition layer considerably inhibited the corrosion owing to the lack of precipitates.Overall,high temperature oxidation provides an efficient,economic and safe approach to inhibit the corrosion of WE43 L-PBF samples,and has promising prospects for future clinical applications.展开更多
This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualis...This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 W.Detailed morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore formation.Lower laser power led to increased pore coverage,whereas a denser structure was observed at higher laser power.This laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the samples.An increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore volume.Lower laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher power.The interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.展开更多
Recent advances in functionally graded additive manufacturing(FGAM)technology have enabled the seamless hybridization of multiple functionalities in a single structure.Soft robotics can become one of the largest benef...Recent advances in functionally graded additive manufacturing(FGAM)technology have enabled the seamless hybridization of multiple functionalities in a single structure.Soft robotics can become one of the largest beneficiaries of these advances,through the design of a facile four-dimensional(4D)FGAM process that can grant an intelligent stimuli-responsive mechanical functionality to the printed objects.Herein,we present a simple binder jetting approach for the 4D printing of functionally graded porous multi-materials(FGMM)by introducing rationally designed graded multiphase feeder beds.Compositionally graded cross-linking agents gradually form stable porous network structures within aqueous polymer particles,enabling programmable hygroscopic deformation without complex mechanical designs.Furthermore,a systematic bed design incorporating additional functional agents enables a multi-stimuli-responsive and untethered soft robot with stark stimulus selectivity.The biodegradability of the proposed 4D-printed soft robot further ensures the sustainability of our approach,with immediate degradation rates of 96.6%within 72 h.The proposed 4D printing concept for FGMMs can create new opportunities for intelligent and sustainable additive manufacturing in soft robotics.展开更多
Soil contamination by hydrocarbons poses numerous environmental, health and agricultural problems. The degradation of these pollutants can occur naturally but very slowly. It is therefore generally necessary to stimul...Soil contamination by hydrocarbons poses numerous environmental, health and agricultural problems. The degradation of these pollutants can occur naturally but very slowly. It is therefore generally necessary to stimulate this degradation by different means. Thus, this study aimed to improve the bio-degradation of diesel and crude oil in a Ghanaian soil by biostimulation. For this, the sampled soil was characterized by standard methods and contaminated with diesel and crude oil at a proportion of 1% (w/w). Then, contaminated soil samples were supplemented with biochar-compost, poultry manure or cow dung at the proportion of 10% (w/w). Periodically, fractions of these samples were taken to evaluate the density of hydrocarbon utilizing bacteria (HUB) and the residual quantities of diesel or crude oil. The characteristics of the soil used show the need for supplementation for better degradation of hydrocarbons. The results of the study show that supplementing the soil with organic substrates increases HUB loads in soils contaminated by diesel and crude oil. They also show that the residual quantities of diesel and crude oil are generally significantly lower in supplemented soils (p = 0.048 and p < 0.0001 respectively). In addition, the study shows that degradation was generally greater in soils contaminated by diesel compared to those contaminated by crude oil, especially at the end of the study.展开更多
Background: Cosmetic formulations, and particularly solar products which contain mineral and chemical UV-filters, are often suspected of causing harmful effects on marine fauna and flora. After the publication of our ...Background: Cosmetic formulations, and particularly solar products which contain mineral and chemical UV-filters, are often suspected of causing harmful effects on marine fauna and flora. After the publication of our work in 2019 concerning the ecotoxicological effects of such formulations on corals (Seriatopora hystrix), we here provide some new information about the biodegradability and the ecotoxicological effects of these products on marine zoo- and phytoplankton. Therefore, we choose to realize in silico and in vitro studies of the biodegradability of several solar products but also to evaluate the ecotoxicological effects of these products on one phytoplankton, i.e. Phaeodactylum tricornutum, and one zooplankton, i.e. Acartia tonsa, of a great importance for sea species survival (notably as sources of food). Materials and methods: Two different approaches were used to study the biodegradability of the tested products: One in silico method and an in vitro one. 2 solar products were involved in the in silico study which consisted in the determination of the degradation factor (DF) of each ingredient of the tested formulas in order to finally obtain their estimated biodegradability percentage. Already available data concerning each ingredient coupled to a computer model developed with one of our partners were used to achieve this study. The in vitro study involved 8 formulas containing UV-filters and was led by following the OECD 301 F guidelines. Ecotoxicological studies of 7 of the formulas containing UV-filters were for their part realized by following the ISO 10253 guidelines for the experiments led with Phaeodactylum tricornutum, and the ISO 14669 guidelines for the experiments led with Acartia tonsa. In these studies, the effect of each tested product on crustaceans’ mortality and algal growth inhibition was assessed. Results: The in silico study predicted that formulas containing chemical UV-filters display a high biodegradability (superior to the threshold value of 60% given by the OECD 301 F guidelines). In the in vitro part of our work, the 8 tested formulas showed a biodegradability slightly inferior to the one predicted in the in silico experiments. Therefore, in order to evaluate if these calculated biodegradability value could have significant harmful effects on zoo- or phytoplankton, we studied the effect of our products regarding the growth inhibition on Phaeodactylum tricornutum and the mortality on Acartia tonsa. In this last part of the study, all the tested products were classified as “non ecotoxic” following an internal classification based on Part 4 entitled “Environmental Hazards” of Globally Harmonized System of Classification and Labelling of Chemicals (GHS), 9<sup>th</sup> edition (2021). Conclusions: These results are notably in line with those published by our teams in 2019 on the effects of solar cosmetic products on corals and seem to confirm that formulas containing mineral and chemical UV-filters can be daily used without displaying significant noxious effects on marine fauna and flora. .展开更多
Recently,the topic of bioresorbable metals,with much focus on magnesium for bone implant applications,has been an area of considerable investigation.Indeed,it could be argued that magnesium is the most promising biode...Recently,the topic of bioresorbable metals,with much focus on magnesium for bone implant applications,has been an area of considerable investigation.Indeed,it could be argued that magnesium is the most promising biodegradable material currently being studied for use as an orthopedic skeletal fixation and joint replacement hardware.However,the fast degradation rate of magnesium-based materials in the physiological environment negatively affects their mechanical integrity and hence limits their biomedical use.The most critical conditions may occur when the implant is subjected to a corrosive physiological environment and a fluctuating load during daily activities.Hence,numerous studies have been published on the synthesis,alloying,and coating of magnesium to control degradation rate and increase strength and durability.Among the materials and strategies employed to achieve these goals,magnesium-based biocomposites have exhibited superior mechanical properties and acceptable biocompatibility.However,there is a lack of understanding of their corrosion and corrosion-fatigue behavior.Such understanding is necessary to qualify these new materials for various bio-implant applications.To this end,this paper reviews the recent advances in the corrosion and corrosion-fatigue behavior of magnesium-based biocomposites.It also provides a comprehensive discussion of different factors that influence the biocompatibility,corrosion,fatigue,and corrosion-fatigue of magnesium-based biocomposites as potential implant materials.This study emphasizes that despite the abundance of various studies on the corrosion behavior of magnesium-based biocomposites,there is an imperative need for more fatigue and corrosion-fatigue studies.展开更多
基金supported by National Natural Science Foundation of China(Grant No. 31772637, 31301981)a Special Fund for Agro-scientific Research in the Public Interest (201403047)
文摘Background:Zearalenone(ZEA)is a resorcylic acid lactone derivative derived from various Fusarium species that are widely found in food and feeds.The molecular structure of ZEA resembles that of the mammalian hormone 17β-oestradiol,thus zearalenone and its metabolites are known to compete with endogenous hormones for estrogen receptors binding sites and to activate transcription of oestrogen-responsive genes.However,the effect of long-term low-dose ZEA exposure on the reproductive response to Bacillus subtilis ANSB01G culture for first-parity gilts has not yet been investigated.This study was conducted to investigate the toxic effects of ZEA as an estrogen receptor selective modulator and the alleviating effects of Bacillus subtilis ANSB01G cultures as ZEA biodegraders in pregnant sows during their first parity.Results:A total of 80 first-parity gilts(Yorkshire×Landrace)were randomly assigned to four dietary treatments during gestation:CO(positive control);MO(negative control,246μg ZEA/kg diet);COA(CO+B.subtilis ANSB01G culture with 2×10^(9)CFU/kg diet);MOA(MO+B.subtilis ANSB01G culture with 2×10^(9)CFU/kg diet).There were 20 replications per treatment with one gilt per replicate.Feeding low-dose ZEA naturally contaminated diets disordered most of reproductive hormones secretion and affected estrogen receptor-αand estrogen receptor-βconcentrations in serum and specific organs and led to moderate histopathological changes of gilts,but did not cause significant detrimental effects on reproductive performance.The addition of Bacillus subtilis ANSB01G culture to the diet can effectively relieve the competence of ZEA to estrogen receptor and the disturbance of reproductive hormones secretion,and then ameliorate toxicosis of ZEA in gilts.Conclusions:Collectively,our study investigated the effects of feeding low-dose ZEA on reproduction in pregnant sows during their first parity.Feeding low-dose ZEA could modulate estrogen receptor-αand-βconcentrations in specific organs,cause disturbance of reproductive hormones and vulva swelling,and damage organ histopathology and up-regulate apoptosis in sow models.Diet with Bacillus subtilis ANSB01G alleviated negative effects of the ZEA on gilts to some extent.
文摘Crude and used engine oil degrading ability of two white rot fungi Pleurotus ostreatus and P. pulmonarius were investigated for six months. One hundred grams of sterilized soil moistened with 75% distilled water (w/v) were weighed into 9 × 9 × 4 cm (350 cm3) jam bottles and mixed thoroughly with bonny light crude oil and used engine oil at different concentrations (0%, 5%, 10%, 15%, 25% and 30%), separately. Each bottle was then inoculated with two agar plugs of a vigorously grown mycelium of P. ostreatus and P. pulmonarius using a sterile cork borer. The bottles were incubated at room temperature for 6 months. The mycelia-ramified waste was separated from soils and analysed for physicochemical parameters such as organic matter, carbon, nitrogen, phosphorus, potassium, pH and total hydrocarbon content, (THC) after drying. The organic carbon, nitrogen and phosphorus contents in contaminated and inoculated soils were increased after six months. However, decrease in potassium, pH and THC occurred in these soils after the period of investigation. P. ostreatus reduced the initial THC to 8% and 9% in soils contaminated with 20% of crude and engine oils, respectively, which was lower than that of P. pulmonarius. The two white rot fungi could be exploited in bioremediation of soils contaminated with bonny light crude and used engine oils.
基金the National Convergence Research of Scientific Challenges through the National Research Foundation of Korea(NRF)the DGIST R&D Program(No.2021M3F7A1082275 and 23-CoE-BT-02)funded by the Ministry of Science and ICT.
文摘Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.
文摘Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body environment.This necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical integrity.In this study,an AZ91 magnesium alloy,as a representative for a biodegradable Mg implant material,was modified with a thin reduced graphene oxide(RGO)-calcium carbonate(CaCO_(3))composite coating.Detailed analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field.
文摘●AIM:To compare the success rate and complications of adjuvant use of mitomycin C and triamcinoloneimpregnated biodegradable nasal packing(TABP)in endoscopic dacryocystorhinostomy(DCR).And to evaluate the efficacy of combining intraoperative mitomycin C and TABP for endoscopic DCR.●METHODS:A total of 198 eyes of 148 patients who underwent endoscopic DCR for acquired nasolacrimal duct obstruction were retrospectively analysed.The patients were randomly divided into three groups:Group A included patients treated without intraoperative mitomycin C but with TABP,Group B included patients treated without triamcinolone but with intraoperative mitomycin C and normal saline-impregnated nasal packing,and Group C included patients treated with intraoperative mitomycin C and TABP.●RESULTS:The results revealed no significant difference in the overall success rates between Groups A(86.8%)and B(89.2%;P=0.377).However,Group C(97.5%)showed a significantly higher overall success rate than Groups A and B.The incidence of granulomas was significantly lower in group C(5%)than in Groups A(20.8%)and B(15.2%;P=0.009).Other complications,such as crust,synechiae,and revision surgery,did not differ significantly among the three groups.●CONCLUSION:The combination of intraoperative mitomycin C and TABP effectively prevents granulomas and enhances surgical success rate.Additionally,there is no statistically significant difference observed between the use of mitomycin C or TABP alone.
基金the Australian Research Council(ARC)through the discovery grant DP210101862。
文摘Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and biodegradability.The primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the implant.Laser surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the material.The composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant applications.Additionally,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.
基金supported by the Hunan Provincial Science and Technology Department Project(2015WK3012)the National Natural Science Foundation of China(No.81571021)+3 种基金R&D of Key Project of Hunan Provincial Science and Technology Department(2022SK2010)R&D of Key Technology of Light Metal Air Battery,Transformation and Industrialization of Scientific and Technological Achievements of Hunan Province(2020GK2071)R&D of Key Technology and Materials of Magnesium Air Battery,Transformation of Scientific and Technological Achievements of Changsha City(Kh2005186)Technology Fundation(2021JCJQ-JJ-0432)。
文摘The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.
基金supported by the KIST Institutional Program (Project No.2E32501-23-106)the KU-KIST Graduate School of Converging Science and Technology Program+3 种基金the National Research Foundation of Korea (NRF) grant funded by the Korean government (the Ministry of Science, ICT, MSIT) (RS-2022-00165524)the development of technologies for electroceuticals of the National Research Foundataion (NRF) funded by the Korean government (MSIT) (RS-2023-00220534)the Ministry of Science and ICT (MSIT), Korea, under the ICT Creative Consilience program (IITP-2023-2020-0-01819) supervised by the IITP (Institute for Information and Communications Technology Planning and Evaluation)Start up Pioneering in Research and Innovation(SPRINT) through the Commercialization Promotion Agency for R&D Outcomes(COMPA) grant funded by the Korea government(Ministry of Science and ICT) (1711198921)
文摘Substrates or encapsulants in soft and stretchable formats are key components for transient,bioresorbable electronic systems;however,elastomeric polymers with desired mechanical and biochemical properties are very limited compared to nontransient counterparts.Here,we introduce a bioresorbable elastomer,poly(glycolide-co-ε-caprolactone)(PGCL),that contains excellent material properties including high elongation-at-break(<1300%),resilience and toughness,and tunable dissolution behaviors.Exploitation of PGCLs as polymer matrices,in combination with conducing polymers,yields stretchable,conductive composites for degradable interconnects,sensors,and actuators,which can reliably function under external strains.Integration of device components with wireless modules demonstrates elastic,transient electronic suture system with on-demand drug delivery for rapid recovery of postsurgical wounds in soft,time-dynamic tissues.
基金supported by the German Research Foundation(DA 2255/1-1to SCD)+4 种基金a SickKids Research Training Competition(RESTRACOMP)Graduate Scholarship(to KJWS)an Ontario Graduate Scholarship(to KJWS)a grant from Natural Sciences and Engineering Research Council of Canada(NSERC)(to KJWS)a Kickstarter grant from the Institute of Biomedical Engineering(BME)at the University of Toronto(to KJWS)the Abe Frank Fund from the Riley’s Children Foundation(GHB)。
文摘Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong disability.Currently,there are no FDA-approved therapies available to promote nerve regeneration.Tacrolimus accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve surgery.The authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug exposure.Tacrolimus is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 days.Size and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible byproducts.Tacrolimus released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic delivery.Given its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.
基金supported by National Key Research and Development Program of China[2023YFB4605800]National Natural Science Foundation of China[51935014,52165043]+3 种基金JiangXi Provincial Natural Science Foundation of China[20224ACB204013,20224ACB214008]Jiangxi Provincial Cultivation Program for Academic and Technical Leaders of Major Subjects[20225BCJ23008]Anhui Provincial Natural Science Foundation[2308085ME171]The University Synergy Innovation Program of Anhui Province[GXXT-2023-025,GXXT-2023-026].
文摘Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.
基金For financial support,the authors gratefully acknowledge the National Natural Science Foundation of China(U2004164)the National Key Research and Development Program of China(2018YFC1106703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251).
文摘The cardiovascular diseases(CVD)continue to be the major threat to global public health over the years,while one of the effective methods to treat CVD is stent intervention.Biomedical magnesium(Mg)alloys have great potential applications in cardiovascular stents benefit from their excellent biodegradability and absorbability.However,excessive degradation rate and the delayed surface endothelialization still limit their further application.In this study,we modified a Mg-Zn-Y-Nd alloy(ZE21B)by preparing MgF_(2) as the corrosion resistance layer,the dopamine polymer film(PDA)as the bonding layer,and hyaluronic acid(HA)loaded astaxanthin(ASTA)as an important layer to directing the cardiovascular cells fate.The electrochemical test results showed that the MgF_(2)/PDA/HA-ASTA coating improved the corrosion resistance of ZE21B.The cytocompatibility experiments also demonstrated that this novel composite coating also selectively promoted endothelial cells proliferation,inhibited hyperproliferation of smooth muscle cells and adhesion of macrophages.Compared with the HAloaded rapamycin(RAPA)coating,our MgF_(2)/PDA/HA-ASTA coating showed better blood compatibility and cytocompatibility,indicating stronger multi-functions for the ZE21B alloy on cardiovascular application.
基金supported by the following funds:National Natural Science Foundation of China(51935014,52165043)Jiangxi Provincial Cultivation Program for Academic and Technical Leaders of Major Subjects(20225BCJ23008)+1 种基金Jiangxi Provincial Natural Science Foundation(20224ACB204013,20224ACB214008)Scientific Research Project of Anhui Universities(KJ2021A1106)。
文摘Magnesium(Mg)alloys are considered to be a new generation of revolutionary medical metals.Laser-beam powder bed fusion(PBF-LB)is suitable for fabricating metal implants withpersonalized and complicated structures.However,the as-built part usually exhibits undesirable microstructure and unsatisfactory performance.In this work,WE43 parts were firstly fabricated by PBF-LB and then subjected to heat treatment.Although a high densification rate of 99.91%was achieved using suitable processes,the as-built parts exhibited anisotropic and layeredmicrostructure with heterogeneously precipitated Nd-rich intermetallic.After heat treatment,fine and nano-scaled Mg24Y5particles were precipitated.Meanwhile,theα-Mg grainsunderwent recrystallization and turned coarsened slightly,which effectively weakened thetexture intensity and reduced the anisotropy.As a consequence,the yield strength and ultimate tensile strength were significantly improved to(250.2±3.5)MPa and(312±3.7)MPa,respectively,while the elongation was still maintained at a high level of 15.2%.Furthermore,the homogenized microstructure reduced the tendency of localized corrosion and favoredthe development of uniform passivation film.Thus,the degradation rate of WE43 parts was decreased by an order of magnitude.Besides,in-vitro cell experiments proved their favorable biocompatibility.
基金support of the Australian Research Council through the ARC Research Hub for Advanced Manufacturing of Medical Devices(IH150100024).J.Venezuela is also supported by the Advance Queensland Industry Research Fellowship(AQIRF114-2019RD2).
文摘UHP Mg-Ge alloys was recently found to provide excellent corrosion resistance.This paper provides new insights on the mechanism of improved corrosion resistance of UHP Mg-Ge alloys in Hanks’solution.The studied UHP Mg-0.5Ge and UHP Mg-1Ge alloys showed superior corrosion resistance compared to UHP Mg and WE43,with the Mg-1Ge exhibiting the best corrosion performance.The exceptional corrosion resistance of the UHP alloy is attributed to(i)Mg_(2)Ge’s ability to suppress cathodic kinetics,(ii)Ge’s capability to accelerate the formation of a highly passive layer,and the(iii)low amounts of corrosion-accelerating impurities.
基金the National Natural Science Foundation of China(52100157,52176197,and 52100156)the National Key Research and Development Program of China(2022YFD1601100).
文摘In recent years,a great deal of attention has been focused on the environmental impact of plastics,includ-ing the carbon emissions related to plastics,which has promoted the application of biodegradable plas-tics.Countries worldwide have shown high interest in replacing traditional plastics with biodegradable plastics.However,no systematic comparison has been conducted on the carbon emissions of biodegrad-able versus traditional plastic products.This study evaluates the carbon emissions of traditional and biodegradable plastic products(BPPs)over four stages and briefly discusses environmental and economic perspectives.Four scenarios-namely,the traditional method,chemical recycling,industrial composting,and anaerobic digestion-are considered for the disposal of waste BPPs(WBPPs).The analysis takes China as a case study.The results show that the carbon emissions of 1000traditional plastic products(plastic bags,lunch boxes,cups,etc.)were52.09-150.36 carbon emissions equivalent of per kilogram(kg CO_(2)eq),with the stage of plastic production contributing 50.71%-50.77%.In comparison,1000 similar BPPs topped out at 21.06-56.86 kg CO_(2)eq,approximately 13.53%-62.19%lower than traditional plastic prod-ucts.The difference was mainly at the stages of plastic production and waste disposal,and the BPPs showed significant carbon reduction potential at the raw material acquisition stage.Waste disposal plays an important role in environmental impact,and composting and anaerobic digestion are considered to be preferable disposal methods for WBPPs.However,the high cost of biodegradable plastics is a challenge for their widespread use.This study has important reference significance for the sustainable development of the biodegradableplastics industry.
基金funded by the National Key Research and Development Program of China (2018YFE0104200)National Natural Science Foundation of China (51875310, 52175274, 82172065)Tsinghua Precision Medicine Foundation
文摘Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid corrosion.In this work,dense WE43 L-PBF samples were built with the relativity density reaching 99.9%.High temperature oxidation was performed on the L-PBF samples in circulating air via various heating temperatures and holding durations.The oxidation and diffusion at the elevated temperature generated a gradient structure composed of an oxide layer at the surface,a transition layer in the middle and the matrix.The oxide layer consisted of rare earth(RE)oxides,and became dense and thick with increasing the holding duration.The matrix was composed ofα-Mg,RE oxides and Mg_(24)RE_(5) precipitates.The precipitates almost disappeared in the transition layer.Enhanced passivation effect was observed in the samples treated by a suitable high temperature oxidation.The original L-PBF samples lost 40%weight after 3-day immersion in Hank’s solution,and broke into fragments after 7-day immersion.The casted and solution treated samples lost roughly half of the weight after 28-day immersion.The high temperature oxidation samples,which were heated at 525℃ for 8 h,kept the structural integrity,and lost only 6.88%weight after 28-day immersion.The substantially improved corrosion resistance was contributed to the gradient structure at the surface.On one hand,the outmost dense layer of RE oxides isolated the corrosive medium;on the other hand,the transition layer considerably inhibited the corrosion owing to the lack of precipitates.Overall,high temperature oxidation provides an efficient,economic and safe approach to inhibit the corrosion of WE43 L-PBF samples,and has promising prospects for future clinical applications.
基金supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region(152131/18E).
文摘This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 W.Detailed morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore formation.Lower laser power led to increased pore coverage,whereas a denser structure was observed at higher laser power.This laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the samples.An increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore volume.Lower laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher power.The interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.
基金supported by National R&D Program through the NRF funded by Ministry of Science and ICT(2021M3D1A2049315)and the Technology Innovation Program(20021909,Development of H2 gas detection films(?0.1%)and process technologies)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)supported by the Basic Science Program through the NRF of Korea,funded by the Ministry of Science and ICT,Korea.(Project Number:NRF-2022R1C1C1008845)supported by Basic Science Research Program through the NRF funded by the Ministry of Education(Project Number:NRF-2022R1A6A3A13073158)。
文摘Recent advances in functionally graded additive manufacturing(FGAM)technology have enabled the seamless hybridization of multiple functionalities in a single structure.Soft robotics can become one of the largest beneficiaries of these advances,through the design of a facile four-dimensional(4D)FGAM process that can grant an intelligent stimuli-responsive mechanical functionality to the printed objects.Herein,we present a simple binder jetting approach for the 4D printing of functionally graded porous multi-materials(FGMM)by introducing rationally designed graded multiphase feeder beds.Compositionally graded cross-linking agents gradually form stable porous network structures within aqueous polymer particles,enabling programmable hygroscopic deformation without complex mechanical designs.Furthermore,a systematic bed design incorporating additional functional agents enables a multi-stimuli-responsive and untethered soft robot with stark stimulus selectivity.The biodegradability of the proposed 4D-printed soft robot further ensures the sustainability of our approach,with immediate degradation rates of 96.6%within 72 h.The proposed 4D printing concept for FGMMs can create new opportunities for intelligent and sustainable additive manufacturing in soft robotics.
文摘Soil contamination by hydrocarbons poses numerous environmental, health and agricultural problems. The degradation of these pollutants can occur naturally but very slowly. It is therefore generally necessary to stimulate this degradation by different means. Thus, this study aimed to improve the bio-degradation of diesel and crude oil in a Ghanaian soil by biostimulation. For this, the sampled soil was characterized by standard methods and contaminated with diesel and crude oil at a proportion of 1% (w/w). Then, contaminated soil samples were supplemented with biochar-compost, poultry manure or cow dung at the proportion of 10% (w/w). Periodically, fractions of these samples were taken to evaluate the density of hydrocarbon utilizing bacteria (HUB) and the residual quantities of diesel or crude oil. The characteristics of the soil used show the need for supplementation for better degradation of hydrocarbons. The results of the study show that supplementing the soil with organic substrates increases HUB loads in soils contaminated by diesel and crude oil. They also show that the residual quantities of diesel and crude oil are generally significantly lower in supplemented soils (p = 0.048 and p < 0.0001 respectively). In addition, the study shows that degradation was generally greater in soils contaminated by diesel compared to those contaminated by crude oil, especially at the end of the study.
文摘Background: Cosmetic formulations, and particularly solar products which contain mineral and chemical UV-filters, are often suspected of causing harmful effects on marine fauna and flora. After the publication of our work in 2019 concerning the ecotoxicological effects of such formulations on corals (Seriatopora hystrix), we here provide some new information about the biodegradability and the ecotoxicological effects of these products on marine zoo- and phytoplankton. Therefore, we choose to realize in silico and in vitro studies of the biodegradability of several solar products but also to evaluate the ecotoxicological effects of these products on one phytoplankton, i.e. Phaeodactylum tricornutum, and one zooplankton, i.e. Acartia tonsa, of a great importance for sea species survival (notably as sources of food). Materials and methods: Two different approaches were used to study the biodegradability of the tested products: One in silico method and an in vitro one. 2 solar products were involved in the in silico study which consisted in the determination of the degradation factor (DF) of each ingredient of the tested formulas in order to finally obtain their estimated biodegradability percentage. Already available data concerning each ingredient coupled to a computer model developed with one of our partners were used to achieve this study. The in vitro study involved 8 formulas containing UV-filters and was led by following the OECD 301 F guidelines. Ecotoxicological studies of 7 of the formulas containing UV-filters were for their part realized by following the ISO 10253 guidelines for the experiments led with Phaeodactylum tricornutum, and the ISO 14669 guidelines for the experiments led with Acartia tonsa. In these studies, the effect of each tested product on crustaceans’ mortality and algal growth inhibition was assessed. Results: The in silico study predicted that formulas containing chemical UV-filters display a high biodegradability (superior to the threshold value of 60% given by the OECD 301 F guidelines). In the in vitro part of our work, the 8 tested formulas showed a biodegradability slightly inferior to the one predicted in the in silico experiments. Therefore, in order to evaluate if these calculated biodegradability value could have significant harmful effects on zoo- or phytoplankton, we studied the effect of our products regarding the growth inhibition on Phaeodactylum tricornutum and the mortality on Acartia tonsa. In this last part of the study, all the tested products were classified as “non ecotoxic” following an internal classification based on Part 4 entitled “Environmental Hazards” of Globally Harmonized System of Classification and Labelling of Chemicals (GHS), 9<sup>th</sup> edition (2021). Conclusions: These results are notably in line with those published by our teams in 2019 on the effects of solar cosmetic products on corals and seem to confirm that formulas containing mineral and chemical UV-filters can be daily used without displaying significant noxious effects on marine fauna and flora. .
文摘Recently,the topic of bioresorbable metals,with much focus on magnesium for bone implant applications,has been an area of considerable investigation.Indeed,it could be argued that magnesium is the most promising biodegradable material currently being studied for use as an orthopedic skeletal fixation and joint replacement hardware.However,the fast degradation rate of magnesium-based materials in the physiological environment negatively affects their mechanical integrity and hence limits their biomedical use.The most critical conditions may occur when the implant is subjected to a corrosive physiological environment and a fluctuating load during daily activities.Hence,numerous studies have been published on the synthesis,alloying,and coating of magnesium to control degradation rate and increase strength and durability.Among the materials and strategies employed to achieve these goals,magnesium-based biocomposites have exhibited superior mechanical properties and acceptable biocompatibility.However,there is a lack of understanding of their corrosion and corrosion-fatigue behavior.Such understanding is necessary to qualify these new materials for various bio-implant applications.To this end,this paper reviews the recent advances in the corrosion and corrosion-fatigue behavior of magnesium-based biocomposites.It also provides a comprehensive discussion of different factors that influence the biocompatibility,corrosion,fatigue,and corrosion-fatigue of magnesium-based biocomposites as potential implant materials.This study emphasizes that despite the abundance of various studies on the corrosion behavior of magnesium-based biocomposites,there is an imperative need for more fatigue and corrosion-fatigue studies.