Large-Scale Preparation of Mechanically High-Performance and Biodegradable PLA/PHBV Melt-Blown Nonwovens with Nanofibers

Biodegradable polylactic acid(PLA)melt-blown nonwovens are attractive candidates to replace nondegradable polypropylene melt-blown nonwovens.However,it is still an extremely challenging task to prepare PLA melt-blown nonwovens with sufficient mechanical properties for practical application.Herein,we report a simple strategy for the large-scale preparation of biodegradable PLA/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)melt-blown nonwovens with high strength and excellent toughness.In this process,a small amount of PHBV is added to PLA to improve the latter’s crystallization rate and crystallinity.In addition,when the PHBV content increases from 0 to 7.5 wt%,the diameters of the PLA/PHBV melt-blown fibers decrease significantly(with the proportion of nanofibers increasing from 7.7%to 42.9%).The resultant PLA/PHBV(5 wt%PHBV)melt-blown nonwovens exhibit the highest mechanical properties.The tensile stress,elongation,and toughness of PLA/PHBV(5 wt%PHBV)melt-blown nonwovens reach 2.5 MPa,45%,and 1.0 MJm3,respectively.More importantly,PLA/PHBV melt-blown nonwovens can be completely degraded into carbon dioxide and water after four months in the soil,making them environmentally friendly.A general tensile-failure model of melt-blown nonwovens is proposed in this study,which may shed light on mechanical performance enhancement for nonwovens.

Graphene-calcium carbonate coating to improve the degradation resistance and mechanical integrity of a biodegradable implant

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.

Transcriptomic analysis of molecular mechanisms underlying the biodegradation of organophosphorus pesticide chlorpyrifos by Lactobacillus delbrueckii ssp.bulgaricus in skimmed milk

Bioremediation of organophosphorus pesticides in contaminated foodstuffs using probiotics has been increasingly under the spotlight in recent years,though the biodegradation mechanism and derived intermediate products remain unclear.This study aimed to help fill this knowledge gap and examined the degradation mechanism of organophosphorus pesticide,chlorpyrifos,in milk by Lactobacillus delbrueckii ssp.bulgaricus using gas chromatography-tandem mass spectrometry(GC-MS/MS)combined with transcriptome analysis.After the strain was cultured for 20 h in the presence of chlorpyrifos,differential expressions of 383 genes were detected,including genes probably implicated during chlorpyrifos degradation such as those related to hydrolase,phosphoesterase,diphosphatase,oxidoreductase,dehydratase,as well as membrane transporters.GC-MS/MS analysis revealed the changes of secondary metabolites in L.bulgaricus during milk fermentation due to chlorpyrifos stress.6-Methylhexahydro-2H-azepin-2-one,2,6-dihydroxypyridine and methyl 2-aminooxy-4-methylpentanoate as intermediates,along with the proposed pathways,might be involved in chlorpyrifos biodegradation by L.bulgaricus.

Effects of biodegradation on diamondoid distribution in crude oils from the Bongor Basin,Chad

The sensitivity of biodegradation on diamondoids was investigated using a series of biodegraded oil samples from the Ronier tectonic unit of Bongor Basin,Chad.The results suggest that diamondoids,including adamantanes(As)and diamantanes(Ds),are relatively resistant to biodegradation and obvious biodegradation was observed in oils with a Peters-Moldowan(PM)biodegradation rank of 6 or more.Overall,the sensibility of biodegradation on diamondoids is generally similar to hopanes and regular steranes.As biodegradation evolves,the changes in concentration and components of diamondoids show that the biodegradation process is selective and stepwise.The significant increase of MD/MA and DMD/DMA for oils with a PM ranking 6^(+) indicates that diamantanes are generally more resistant to biodegradation than adamantanes.The similar trends of DMA/MA,EA/MA,MD/D,DMD/MD and other relevant indexes,show that higher alkylation homologs are more resistant to biodegradation.The commonly used diamondoid ratios,such as MAI,EAI,MDI and DMID-1,are obviously affected by biodegradation at the stage of high-level biodegradation,which may indicate that these ratios should be used with caution in case of severely degraded oils.

Investigation of bioactivity and biodegradability of Mg-bioceramic implants:An in vitro study for biomedical applications

In this study,Mg-based composites,by the addition of ZnO,Ca_(2)ZnSi_(2)O_(7),Ca_(2)MgSi_(2)O_(7),and CaSiO_(3)as bioactive agents,were fabricated using friction stir processing.The microstructure and in vitro assessment of bioactivity,biodegradation rate,and corrosion behavior of the resultant composites were investigated in simulated body fluid(SBF).The results showed that during the immersion of composites in SBF for 28 d,due to the release of Ca^(2+)and PO_(4)^(3-)ions,hydroxyapatite(HA)crystals with cauliflower shaped morphology were deposited on the surface of composites,confirming good bioactivity of composites.In addition,due to the uniform distribution of bioceramic powders throughout Mg matrix,grain refinement of the Mg matrix,and uniform redistribution of secondary phase particles,the polarization resistance increased,and the biodegradation rate of composites significantly reduced compared to monolithic Mg matrix.The polarization corrosion resistance of Mg-ZnO increased from 0.216 to 2.499 kΩ/cm^(2)compared to monolithic Mg alloy.Additionally,Mg-ZnO composite with the weight loss of 0.0217 g after 28 d immersion showed lower weight loss compared to other samples with increasing immersion time.Moreover,Mg-ZnO composite with the biodegradation rate of 37.71 mm/a exhibited lower biodegradation rate compared to other samples with increasing immersion time.

A multi-functional MgF_(2)/polydopamine/hyaluronan-astaxanthin coating on the biodegradable ZE21B alloy with better corrosion resistance and biocompatibility for cardiovascular application

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.

Improving corrosion resistance of additively manufactured WE43 magnesium alloy by high temperature oxidation for biodegradable applications

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.

Direct 4D printing of functionally graded hydrogel networks for biodegradable,untethered,and multimorphic soft robots

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.

Degradation Rate Assessment of Biodegradable Magnesium Alloys

Biodegradable magnesium alloys have been widely used in medical implants. But safety concerns were put forward for the high degradation rate of biodegradable magnesium alloy. The optimal biodegradable magnesium alloys that give rise to the desired degradation rate hasn’t yet to be defined. Assessing the degradation rate of biodegradable magnesium alloys involves in vitro testing, in vivo testing, numerical modeling, understanding the factors influencing their degradation in physiological environments, biocompatibility testing, and clinical studies. It is important to standardize analytical tools aimed at assessing the degradation rate of biodegradable magnesium alloys. It is advisable to identify the threshold for safe degradation rate of biodegradable magnesium alloys in biomedical applications.

Machine Learning Based Virtual Screening for Biodegradable Polyesters

Current biodegradation timelines show that polyesters take over 200 years to break down. A crucial component of several industries, polyesters are relied upon for materials development and thus require sustainable alternatives. Recent works in generative modeling have made it possible to produce large sets of chemical structures, but current molecular screening methods are expensive, not scalable, and are oversimplified. This work evaluates whether a molecule’s biodegradability potential can be accurately predicted by training a model on recent experimental data. Additionally, three chemical descriptors were evaluated on the final molecules for their effects on biodegradability: molecular structure, bond types, and solubility. A Gradient Boosted Machine was trained on a dataset of 600 molecules and their binary labels on biodegradability. The classification model effectively captured the biodegradability property, yielding an Area Under the Receiver Operating Characteristics, AUROC, of 84% and an Area Under the Precision Recall Curve, or AUPRC, of 87%. Additionally, an existing amortized synthetic tree generation model, SynNet, validated each molecule by showing chemical synthesizability and producing simple and interpretable synthesis pathways. This approach of filtering by prediction and chemical rule interpretation is inexpensive, highly scalable and can capture the necessary complexity. Using this method, novel polyester candidates can be polymerized and produced into sustainable fabrics, reducing environmental stress from textile-reliant industries.

New Insights in the Biodegradability and the Ecotoxicological Effects of Solar Products Containing Mineral and Chemical UV-Filters on Marine Zoo- and Phytoplanktons: An in silico and in vitro Study

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), 9th 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. .

可降解药物洗脱消化道支架的研究进展与前景

背景:目前消化道支架的临床应用较为普遍,常规的自膨胀金属及塑料支架存在易移位、取出困难、术后再狭窄等问题,可降解药物洗脱消化道支架凭借生物可降解、术后再狭窄率低等优点成为消化道支架研究的热点。目的:总结可降解药物洗脱消化道支架的研究进展,对可降解药物洗脱消化道支架的前景作出展望。方法:检索中国知网、万方、Pub Med、Web of Science数据库中1994年1月至2024年3月发表的相关文献,中文检索词为“可降解,药物洗脱支架,食管支架,胆道支架,胰管支架,肠道支架,消化道支架”,英文检索词为“biodegradable,drug-eluting stent,esophageal stent,biliary stent,pancreatic duct stent,intestinal stent,gastrointestinal stent”,最终纳入64篇文献进行综述分析。结果与结论:(1)可降解药物洗脱消化道支架以生物可降解材料为主体,搭载并局部洗脱不同治疗目的的药物,发挥物理支撑及药物治疗双重作用。通过调整支架材料性质、改进制造工艺及辅助手段可以加快或减缓支架降解速度,满足临床需求。药物洗脱技术以药物涂层、纳米颗粒、聚合物载药膜等为载药平台,使药物精准释放,提高病变部位局部药物浓度,减少药物损耗及毒性药物的全身吸收量。(2)可降解药物洗脱消化道支架主要为一种或多种功能性药物结合可生物降解聚合物、金属或纳米纤维材料。可用的功能性药物分为抗炎抗增生类、抗肿瘤类、溶石类、酶抑制剂类。(3)维持支架机械性能稳定和精准控释药物是可降解药物洗脱消化道支架现阶段需要解决的问题,开发新型可降解消化道支架,研究新型载药及释药方式、制造工艺和辅助手段是未来研究方向。

Effect of beta-cypermethrin on GPT and GOT activities of crucian serum

In this experiment, the effects of beta-cypermethrin on acute toxicity and serum GPT and GOT of crucian were studied. It was indicated that the 96hLC50 of beta-cypermethrin was 11.4 μg L-1. The crucian serum was treated at the levels, 0 μg L-1, 0.114 μg L-1, 0.57 μg L-1, 1.14 μg L-1 for 0 d 5 d 10 d 15 d and 20 d, respectively. The results showed that beta-cypermethrin could make great damage to crucian biochemical characteristics, and suggested that the effects of toxicant on serum GPT and GOT could be used as an index of toxicological assessment.

Study on biodegradated ability of thirteen edible fungi to straw

The biodegradated abilities of 13 edible fungi to straw were studied. The results showed that all the experimental fungi except Tricholama mongolicum had definite biodegradated abilities to the lignin and cellulose of straw. The Ideal fungus for straw degradation was screened out as Pleurotus ostreatus, which showed a higher degradation ability for lignin (17.86%) and lower degradation rate for cellulose (2.24%), with a Selection Factor (SF) of 7.97. The degradation rates of lignin and cellulose for other fungi ranged from 2.30% to 16.54% and 5.60% to 17.32%, respectively, and the SF was very low in range of 0.14 to 2.24.The ratio of colony's diameters to the color-zone (d1/d2) and SF are negative correlation, with a correlation coefficient of -0.1476.

The Application Effects of Truly Biodegradable Mulch in Potato Farmlands

[Objective] The aim was to explore application effects of truly biodegradable mulch in farmlands and provide data support for large area spreading on southern potato fields. [Method] The field plot experiments were conducted to investigate mulch film＇s weight loss and the effects of using truly biodegradable mulch film on potato yield and agronomic characters. [Result] The emergence rates of truly biodegradable mulch film and black plastic mulch film kept 9.71% and9.27% higher compared with the open field, and yield increased by 30.84% and36.81%. In the potato harvest period, the truly biodegradable mulch films already broke, and mulch film＇s weight loss rate was 58.62%. It can be completely degraded in the field after some time, and following crops would not be affected. [Conclusion] Truly biodegradable mulch performs significantly in increasing yield and keeps higher in weight-loss rate, so that it has a promising future.

Processing of Aniline Aerofloat Wastewater with SBR System and Its Biodegradation Mechanism

ObjectiveThis study aimed to investigate the biodegradation effect and biodegradation mechanism of aniline aerofloat wastewater. MethodSmall-scale processing of simulated aniline aerofloat wastewater was carried out with SBR （Sequencing Batch Reactor） system; intermediate products in the process were analyzed using high-performance liquid chromatography. ResultAccording to the experimental results, the small-scale process was basically stably operated after 40 days of activation and regulation, leading to relatively ideal degradation effect on aniline aerofloat, the COD removal efficiency reached 64.3% , degradation rate of aniline aerofloat reached 93.4%, which could be applied in the treatment of mine flotation wastewater containing such pollutant. During the degradation process, pH increased from 5.83 to 6.60 and then dropped to 6.17, which might be caused by the thiocyanate ions and aniline generated in the degradation process. Aniline aerofloat mainly produced two preliminary products during the biodegradation process： aniline and a substance that was difficult to be biodegraded under aerobic conditions, which was the main reason for the relatively high COD value in effluent. Furthermore, aniline was eventually biodegraded. ConclusionThis study provided basis for the development of biological treatment of flotation wastewater in China and showed great significance for the improvement of ecological environment around the mines.

PROPERTIES OF BIODEGRADABLE THERMOPLASTIC STARCH

Thermoplastic starch is a kind of modified starch produced by mixing starch with additives and processing the mixture in an extruder. The mechanical properties, including tensile strength and elongation at break, biodegradability and rheological properties were studied. Glycerol and urea, to some extent, can both decrease the tensile strength and increase percentage elongation at break, because the former acts as a plasticizer and the latter can break down interactions among starch macromolecules. Thermoplastic starch shows thermoplasticity and its melt behaves as a pseudoplastic liquid at a low shear rate. Its biodegrading extent is slightly higher than that of native starch. The molecular weight of starch displays a decreasing tendency after thermoplastic modification.

Ozonation and Biodegradability of Lignin in Water

To convert the non biodegradable sodium lignin sulfonate into biodegradable substances, the sodium lignin sulfonate in the water was ozonized and the pH value, dissolved organic carbon(DOC), ultraviolet absorbency at λ =254 nm(UVA) and the biodegradability of the ozonation effluent were measured. The non biodegradable sodium lignin sulfonate can be partly converted into biodegradable substances by ozonation (about 38 76%). In the ozonation process, there is little DOC decrease, but much UVA decrease and obvious pH drop.

可降解锌基合金在骨缺损修复重建中的应用及研究热点和不足

背景:锌基合金医用植入材料有优异的力学性能、完全可降解性、良好的生物相容性,主要用于骨科植入物、心血管支架、胆管支架、气管支架、神经导管等。目的:综述可降解锌基合金应用于骨缺损修复的研究进展,展望锌基材料可期研究方向与成果。方法:检索PubMed、Web of Science、万方及中国知网数据库,选择各数据库建库至2023年6月收录的各类可降解锌基合金用于骨植入材料研究的相关文献,对生物可降解锌基合金的基本特性进行概述,对锌基合金促进骨组织修复作用进行梳理和归纳总结,讨论当前的研究热点与不足。结果与结论:①锌基合金具备良好的生物相容性,以锌基合金为基体材料,借助支架结构构建技术和涂层优化工艺将有效提高锌基合金的骨传导性,并且使其降解产物具备高效骨诱导性,以调控成骨、破骨细胞的基因表达,促进骨缺损后的修复重建;②然而在锌基合金优化的研究中,涂层工艺相对不足,增材负载技术尚缺乏;③锌基合金拥有良好的机械、生物特性,通过特殊工艺可增加材料的骨传导性、骨诱导性以有效提高其促进骨修复重建能力,并有望进一步实现个性化移植材料的研发。优化涂层与增材负载等技术融合于锌基合金的研究有待进一步探讨。

不同地膜的降解特征及其对旱区马铃薯生长和土壤微环境的影响

为筛选适宜宁南旱区马铃薯生长且对土壤环境友好的降解地膜类型,以不覆盖为对照,研究普通塑料膜、秸秆纤维地膜、生物降解膜的降解特征及其对马铃薯生长、土壤微环境的影响。结果表明,生物降解膜和秸秆纤维膜分别在播后90和60 d进入诱导期,生物降解膜和秸秆纤维膜均在播后150 d进入碎裂期;播后150 d的地膜质量损失率以秸秆纤维地膜最高,而普通塑料膜无明显变化。播后60 d,生物降解膜和秸秆纤维膜处理土壤蓄水量分别较对照显著提高21.4%和10.3%,而普通塑料膜处理与对照差异不显著。播后90~120 d,秸秆纤维膜和生物降解膜处理平均土壤温度分别较对照显著增加1.2和0.8℃。播后150 d,与对照相比,普通塑料膜和秸秆纤维膜处理土壤速效磷、速效钾含量提升效果显著。秸秆纤维膜处理细菌数量最高,而生物降解膜处理真菌和放线菌数量最高。播后150 d马铃薯地上部和地下部干物质累积量均以生物降解膜处理最高,马铃薯株高、茎粗和增产效果均以秸秆纤维膜处理最为显著。主成分分析结果表明,土壤细菌、放线菌数量是影响地膜降解的主要因素,而播后30~60 d土壤水分和播后60~120 d膜质量损失率对马铃薯产量形成至关重要。综上,秸秆纤维地膜降解效果优于普通塑料膜,且对改善旱地土壤微环境效果显著,可实现马铃薯增产,可代替普通地膜应用于旱作马铃薯生产中。本研究结果对筛选适宜宁南旱区农业可持续发展的最佳地膜类型具有一定的现实意义。