Flotation separation of calcite from fluorite is a challenge on low-grade fluorite flotation that limits the recovery and purity of fluorite concentrate.A new acid leaching–flotation process for fluorite is proposed ...Flotation separation of calcite from fluorite is a challenge on low-grade fluorite flotation that limits the recovery and purity of fluorite concentrate.A new acid leaching–flotation process for fluorite is proposed in this work.This innovative process raised the fluor-ite’s grade to 97.26wt%while producing nanoscale calcium carbonate from its leachate,which contained plenty of calcium ions.On the production of nanoscale calcium carbonate,the impacts of concentration,temperature,and titration rate were examined.By modifying the process conditions and utilizing crystal conditioning agents,calcite-type and amorphous calcium carbonates with corresponding particle sizes of 1.823 and 1.511μm were produced.The influence of the impurity ions Mn^(2+),Mg^(2+),and Fe^(3+)was demonstrated to reduce the particle size of nanoscale calcium carbonate and make crystal shape easier to manage in the fluorite leach solution system compared with the calcium chloride solution.The combination of the acid leaching–flotation process and the nanoscale calcium carbonate preparation method improved the grade of fluorite while recovering calcite resources,thus presenting a novel idea for the effective and clean usage of low-quality fluorite resources with embedded microfine particles.展开更多
Molybdenum disulfide （MoS2）, a typical transition-metal dichalcogenide, has attracted increasing attention in the field of nanomedicine because of its preeminent properties. In this study, magnetic resonance imaging...Molybdenum disulfide （MoS2）, a typical transition-metal dichalcogenide, has attracted increasing attention in the field of nanomedicine because of its preeminent properties. In this study, magnetic resonance imaging （MRI）-guided chemo-photothermal therapy of human breast cancer xenograft in nude mice was demonstrated using a novel core/shell structure of Fe3O4@MoS2 nanocubes （IOMS NCs） via the integration of MoS2 （MS） film onto iron oxide （IO） nanocubes through a facile hydrothermal method. After the necessary PEGylation modification of the NCs for long-circulation purposes, such PEGylated NCs were further capped by 2-deoxy-D-glucose （2-DG）, a non-metabolizable glucose analogue to increase the accumulation of the as-prepared NCs at the tumor site, as 2-DG molecules could be particularly attractive to resource-hungry cancer cells. Such 2-DG- modified PEGylated NCs （IOMS-PEG-2DG NCs） acted as drug-carriers for doxorubicin （DOX）, which could be easily loaded within the NCs. The obtained IOMS-PEG（DOX）-2DG NCs exhibited a 3？2 relaxivity coefficient of 48.86 （mM）^-1·s^-1 and excellent photothermal performance. 24 h after intravenous injection of IOMS-PEG（DOX）-2DG NCs, the tumor site was clearly detected by enhanced T2-weighted MRI signal. Upon exposure to an NIR 808-nm laser for 5 rain at a low power density of 0.5 W·cm^-2 a marked temperature increase was noticed within the tumor site, and the tumor growth was efficiently inhibited by the chemo-photothermal effect. Therefore, our study highlights an excellent theranostic platform with great potential for targeted MRI-guided precise chemo-photothermal therapy of breast cancer.展开更多
Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,...Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,Chryseobacterium sp.,Hymenobacter sp.,Mycobacterium sp.,and Stenotrophomonas sp.were isolated from soil samples.Optimization of enzyme production yield was investigated in various fermentation conditions using response surface methodology.All isolates exhibited maximum GI activity at 40℃,pH 6–8 after 4 days of incubation.A mixture of peptone/yeast extract or tryptone/peptone enhanced higher enzyme production.The same trend was observed in fermentation medium containing 1%xylose or 2%–2.5%wheat straw.This study advanced the knowledge of these bacterial isolates in promoting wheat straw as feedstock for the bio-based industry.展开更多
Natural gas is extensively used as a clean energy source in cities and industries;consequently,there are associ-ated risks of accidental explosions.To reduce the hazards associated with natural gas explosions,it is im...Natural gas is extensively used as a clean energy source in cities and industries;consequently,there are associ-ated risks of accidental explosions.To reduce the hazards associated with natural gas explosions,it is important to study the inherent laws of natural gas blast loads in unconfined spaces and establish load models.Using ex-periments on natural gas explosions in unconfined spaces,this study demonstrates the influence of natural gas concentrations,propagation distances,and gas volumes upon explosion loads.A new load model was proposed for the overpressure-time history curves of natural-gas explosions in an unconfined space.A comparison with the empirical model indicated that the predictive effect was superior to that of previous models,such as the TNT equivalent model and the TNO multi-energy model.展开更多
High fructose corn syrup has been industrially produced by converting glucose to fructose by glucose isomerases,tetrameric metalloenzymes widely used in industrial biocatalysis.Advances in enzyme engineering and comme...High fructose corn syrup has been industrially produced by converting glucose to fructose by glucose isomerases,tetrameric metalloenzymes widely used in industrial biocatalysis.Advances in enzyme engineering and commercial production of glucose isomerase have paved the way to explore more efficient variants of these enzymes.The 5-hydroxymethylfurfural can be produced from high fructose corn syrup catalytic dehydration,and it can be further converted into various furanic compounds chemically or biologically for various industrial applications as a promising platform chemical.Although the chemical conversion of 5-hydroxymethylfurfural into furanic compounds has been extensively investigated in recent years,bioconversion has shown promise for its mild conditions due to the harsh chemical reaction conditions.This review discusses pro-tein engineering potential for improving glucose isomerase production and recent advancements in bioconversion of 5-hydroxymethylfurfural into value-added furanic derivatives.It suggests bi-ological strategies for the industrial transformation of 5-hydroxymethylfurfural.展开更多
Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence anal...Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence analysis of 16S ribosomal RNA gene. Some of the microbes have also been recommended as feed additives for improving the overall growth or production of animals. Rumen bacteria which have potential application in animal feed stuffs were isolated and characterized in this experiment. Isolation was carried out from the rumen of cattle (Bos taurus) using techniques of serial dilutions and repeated tubing of the selectively enriched microbial cultures by using the specific media for rumen bacteria. All the isolates were then screened for in vitro gas production and cellulase enzyme activity and four superior isolates were selected and characterized. There were 18.00% to 23.00% increases in gas production on addition of these isolates to the rumen fluid of cattle and there was better cellulase enzyme activity. Two isolates were identified as Butyrivibrio fibrisolvens, one isolate as Streptococcus species and one isolate as Clostridium aminophilum. This indicated that, these isolates are superior and may have potential to be used as microbial feed additive in ruminants if fed in higher quantity.展开更多
基金supported by the National Key Research Center and Development Program of the 14th Five-Year Plan,China(No.2022YFC2905105)National Natural Science Foundation of China(Nos.52122406 and 52004337)+2 种基金Hunan High-tech Industry Technology Innovation Leading Plan,China(No.2022GK4056)Hunan Innovative Province Construction Special Project,China(No.2020RC3001)Hunan Postgraduate Research and Innovation Project,China(No.CX20220200).
文摘Flotation separation of calcite from fluorite is a challenge on low-grade fluorite flotation that limits the recovery and purity of fluorite concentrate.A new acid leaching–flotation process for fluorite is proposed in this work.This innovative process raised the fluor-ite’s grade to 97.26wt%while producing nanoscale calcium carbonate from its leachate,which contained plenty of calcium ions.On the production of nanoscale calcium carbonate,the impacts of concentration,temperature,and titration rate were examined.By modifying the process conditions and utilizing crystal conditioning agents,calcite-type and amorphous calcium carbonates with corresponding particle sizes of 1.823 and 1.511μm were produced.The influence of the impurity ions Mn^(2+),Mg^(2+),and Fe^(3+)was demonstrated to reduce the particle size of nanoscale calcium carbonate and make crystal shape easier to manage in the fluorite leach solution system compared with the calcium chloride solution.The combination of the acid leaching–flotation process and the nanoscale calcium carbonate preparation method improved the grade of fluorite while recovering calcite resources,thus presenting a novel idea for the effective and clean usage of low-quality fluorite resources with embedded microfine particles.
基金This study was supported by the National Natural Science Foundation of China （NSFC） （No. 81671829）.
文摘Molybdenum disulfide （MoS2）, a typical transition-metal dichalcogenide, has attracted increasing attention in the field of nanomedicine because of its preeminent properties. In this study, magnetic resonance imaging （MRI）-guided chemo-photothermal therapy of human breast cancer xenograft in nude mice was demonstrated using a novel core/shell structure of Fe3O4@MoS2 nanocubes （IOMS NCs） via the integration of MoS2 （MS） film onto iron oxide （IO） nanocubes through a facile hydrothermal method. After the necessary PEGylation modification of the NCs for long-circulation purposes, such PEGylated NCs were further capped by 2-deoxy-D-glucose （2-DG）, a non-metabolizable glucose analogue to increase the accumulation of the as-prepared NCs at the tumor site, as 2-DG molecules could be particularly attractive to resource-hungry cancer cells. Such 2-DG- modified PEGylated NCs （IOMS-PEG-2DG NCs） acted as drug-carriers for doxorubicin （DOX）, which could be easily loaded within the NCs. The obtained IOMS-PEG（DOX）-2DG NCs exhibited a 3？2 relaxivity coefficient of 48.86 （mM）^-1·s^-1 and excellent photothermal performance. 24 h after intravenous injection of IOMS-PEG（DOX）-2DG NCs, the tumor site was clearly detected by enhanced T2-weighted MRI signal. Upon exposure to an NIR 808-nm laser for 5 rain at a low power density of 0.5 W·cm^-2 a marked temperature increase was noticed within the tumor site, and the tumor growth was efficiently inhibited by the chemo-photothermal effect. Therefore, our study highlights an excellent theranostic platform with great potential for targeted MRI-guided precise chemo-photothermal therapy of breast cancer.
基金supported by the Natural Science and Engineering Research Council of Canada(NSERC)Discovery Grant(RGPIN-2017-05366)to WQ.
文摘Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,Chryseobacterium sp.,Hymenobacter sp.,Mycobacterium sp.,and Stenotrophomonas sp.were isolated from soil samples.Optimization of enzyme production yield was investigated in various fermentation conditions using response surface methodology.All isolates exhibited maximum GI activity at 40℃,pH 6–8 after 4 days of incubation.A mixture of peptone/yeast extract or tryptone/peptone enhanced higher enzyme production.The same trend was observed in fermentation medium containing 1%xylose or 2%–2.5%wheat straw.This study advanced the knowledge of these bacterial isolates in promoting wheat straw as feedstock for the bio-based industry.
基金support from the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20180081)the National Key R&D Program of China(Great No.2020YFB2103300)the National Basic Research Program of China(973 Program)(Grant No.2015CB058000).
文摘Natural gas is extensively used as a clean energy source in cities and industries;consequently,there are associ-ated risks of accidental explosions.To reduce the hazards associated with natural gas explosions,it is important to study the inherent laws of natural gas blast loads in unconfined spaces and establish load models.Using ex-periments on natural gas explosions in unconfined spaces,this study demonstrates the influence of natural gas concentrations,propagation distances,and gas volumes upon explosion loads.A new load model was proposed for the overpressure-time history curves of natural-gas explosions in an unconfined space.A comparison with the empirical model indicated that the predictive effect was superior to that of previous models,such as the TNT equivalent model and the TNO multi-energy model.
基金supported by the Natural Sciences and Engineering Research Council of Canada(Grant number RGPIN-2017-05366)to WQ.
文摘High fructose corn syrup has been industrially produced by converting glucose to fructose by glucose isomerases,tetrameric metalloenzymes widely used in industrial biocatalysis.Advances in enzyme engineering and commercial production of glucose isomerase have paved the way to explore more efficient variants of these enzymes.The 5-hydroxymethylfurfural can be produced from high fructose corn syrup catalytic dehydration,and it can be further converted into various furanic compounds chemically or biologically for various industrial applications as a promising platform chemical.Although the chemical conversion of 5-hydroxymethylfurfural into furanic compounds has been extensively investigated in recent years,bioconversion has shown promise for its mild conditions due to the harsh chemical reaction conditions.This review discusses pro-tein engineering potential for improving glucose isomerase production and recent advancements in bioconversion of 5-hydroxymethylfurfural into value-added furanic derivatives.It suggests bi-ological strategies for the industrial transformation of 5-hydroxymethylfurfural.
文摘Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence analysis of 16S ribosomal RNA gene. Some of the microbes have also been recommended as feed additives for improving the overall growth or production of animals. Rumen bacteria which have potential application in animal feed stuffs were isolated and characterized in this experiment. Isolation was carried out from the rumen of cattle (Bos taurus) using techniques of serial dilutions and repeated tubing of the selectively enriched microbial cultures by using the specific media for rumen bacteria. All the isolates were then screened for in vitro gas production and cellulase enzyme activity and four superior isolates were selected and characterized. There were 18.00% to 23.00% increases in gas production on addition of these isolates to the rumen fluid of cattle and there was better cellulase enzyme activity. Two isolates were identified as Butyrivibrio fibrisolvens, one isolate as Streptococcus species and one isolate as Clostridium aminophilum. This indicated that, these isolates are superior and may have potential to be used as microbial feed additive in ruminants if fed in higher quantity.
