γ-Fe_2O_3 nanoparticle-facilitated bisphenol A degradation by white rot fungus

The effect of γ-Fe_2O_3 nanoparticles on bisphenol A(BPA)biodegradation by white rot fungus(Pleurotus ostreatus)was investigated.Interestingly,the addition of γ-Fe_2O_3 nanoparticles enhanced BPA degradation efficiency by as much as 32% after 3 d in the presence of an environmentally relevant concentration of H_2O_2.The γ-Fe_2O_3-induced BPA degradation enhancement was not due to a commonly assumed Fenton-like reaction catalyzed by γ-Fe_2O_3 or dissolved Fe^(3+) ions.However,γ-Fe_2O_3was bioreduced to Fe_3O_4,which was more efficient at catalyzing the Fenton reaction,producing a highly active hydroxyl radical.The bioreduction of γ-Fe_2O_3 was confirmed by X-ray powder diffraction analysis.This study elucidates the potential biotransformation of nanoparticles in the environment and broadens the application of iron oxide nanoparticles for improved pollutant control.

2岁以下新型冠状病毒肺炎患儿快速康复可能与频繁疫苗接种有关

新型冠状病毒肺炎(COVID-19)的重症和死亡与年龄有关,儿童感染者很少重症和死亡,其机制尚不完全清楚.我们回顾性地研究了湖北省十堰市太和医院就诊的186例新冠肺炎患者,发现10岁以下患儿主要临床表现均为轻症,而非成人的严重病症.进一步年龄分层分析发现, 2岁以下患儿更不易合并肺炎支原体共感染,康复时间平均缩短6 d,治疗后淋巴细胞计数回升更明显.患儿康复时间缩短与中西药治疗没有显著关联性,而与其频繁接种疫苗有关.因此, 2岁以下频繁接种疫苗可能激活免疫系统,对新型冠状病毒感染及肺炎支原体共感染具有更强的免疫力.

Complex interplay between formation routes and natural organic matter modification controls capabilities of C_(60)nanoparticles(nC_(60)) to accumulate organic contaminants

Accumulation of organic contaminants on fullerene nanoparticles（nC（60）） may significantly affect the risks of C（60） in the environment.The objective of this study was to further understand how the interplay of nC（60） formation routes and humic acid modification affects contaminant adsorption of nC（60）.Specifically,adsorption of 1,2,4,5-tetrachlorobenzene（a model nonionic,hydrophobic organic contaminant） on nC（60） was greatly affected by nC（60）formation route- the formation route significantly affected the aggregation properties of nC（60）,thus affecting the available surface area and the extent of adsorption via the pore-filling mechanism.Depending on whether nC（60） was formed via the ＂top-down＂ route（i.e.,sonicating C（60） powder in aqueous solution） or ＂bottom-up＂ route（i.e.,phase transfer from an organic solvent） and the type of solvent involved（toluene versus tetrahydrofuran）,modification of nC（60） with Suwannee River humic acid（SRHA） could either enhance or inhibit the adsorption affinity of nC（60）.The net effect depended on the specific way in which SRHA interacted with C（60） monomers and/or C（60） aggregates of different sizes and morphology,which determined the relative importance of enhanced adsorption from SRHA modification via preventing C（60） aggregation and inhibited adsorption through blocking available adsorption sites.The findings further demonstrate the complex mechanisms controlling interactions between nC（60） and organic contaminants,and may have significant implications for the life-cycle analysis and risk assessment of C（60）.

Bioremediation of highly contaminated oilfield soil： Bioaugmentation for enhancing aromatic compounds removal

This study evaluated the effectiveness of different amendments--including a commercial NPK fertilizer, a humic substance （HS）, an organic industrial waste （NovoGro）, and a yeast-bacteria consortium--in the remediation of highly contaminated （up to 6% of total petroleum hydrocarbons） oilfield soils. The concentrations of hydrocarbon, soil toxicity, physicochemical properties of the soil, microbial population numbers, enzyme activities and microbial community structures were examined during the 90-d incubation. The results showed that the greatest degradation of total petroleum hydro- carbons （TPH） was observed with the biostimulation using mixture of NPK, HS and NovoGro, a treatment scheme that enhanced both dehydrogenase and lipase activities in soil. Introduction of exogenous hydrocarbon-degrading bacteria （in addition to biostimulation with NPK, HS and NovoGro） had negligible effect on the removal of TPH, which was likely due to the competition between exogenous and autochthonous microorganisms. None- theless, the addition of exogenous yeast-bacteria consor- tium significantly enhanced the removal of the aromatic fraction of the petroleum hydrocarbons, thus detoxifying the soil. The effect of bioaugmentation on the removal of more recalcitrant petroleum hydrocarbon fraction was likely due to the synergistic effect of bacteria and fungi.

The effect of macropore size of hydroxyapatite scaffold on the osteogenic differentiation of bone mesenchymal stem cells under perfusion culture

Previous studies have proved that dynamic culture could facilitate nutrients transport and apply mechanical stimulation to the cells within three-dimensional scaffolds,thus enhancing the differentiation of stem cells towards the osteogenic phenotype.However,the effects of macropore size on osteogenic differentiation of stem cells under dynamic condition are still unclear.Therefore,the objective of this study was to investigate the effects of macropore size of hydroxyapatite(HAp)scaffolds on osteogenic differentiation of bone mesenchymal stem cells under static and perfusion culture conditions.In vitro cell culture results showed that cell proliferation,alkaline phosphate(ALP)activity,mRNA expression of ALP,collagen-I(Col-I),osteocalcin(OCN)and osteopontin(OPN)were enhanced when cultured under perfusion condition in comparison to static culture.Under perfusion culture condition,the ALP activity and the gene expression of ALP,Col-I,OCN and OPN were enhanced with the macropore size decreasing from 1300 to 800 mm.However,with the further decrease in macropore size from 800 to 500 mm,the osteogenic related gene expression and protein secretion were reduced.Computational fluid dynamics analysis showed that the distribution areas of medium-and high-speed flow increased with the decrease in macropore size,accompanied by the increase of the fluid shear stress within the scaffolds.These results confirm the effects of macropore size on fluid flow stimuli and cell differentiation,and also help optimize the macropore size of HAp scaffolds for bone tissue engineering.