Developing high-performing non-noble transition metal catalysts for H_(2) evolution from chemical hydrogen storage materials is of great significance for the hydrogen economy system, yet challenging. Herein,we present...Developing high-performing non-noble transition metal catalysts for H_(2) evolution from chemical hydrogen storage materials is of great significance for the hydrogen economy system, yet challenging. Herein,we present for the first time that anomalous metastable hexagonal close-packed Ni nanoparticles induced by heteroatom N doping encapsulated in carbon(N-hcp-Ni/C) can exhibit admirable catalytic performance for ammonia borane(AB) dehydrogenation, prominently outperforming conventional fcc Ni counterpart with similar morphology and favorably presenting the state-of-the-art level.Comprehensive experimental and theoretical studies unravel that unusual hcp phase engineering of Ni together with N doping could induce charge redistribution and modulate electronic structure, thereby facilitating H_(2)O adsorption and expediting H_(2)O dissociation(rate-determining step). As a result, AB dehydrogenation can be substantially boosted with the assistance of N-hcp-Ni/C. Our proposed strategy highlights that unconventional crystal phase engineering coupled with non-metal heteroatom doping is a promising avenue to construct advanced transition metal catalysts for future renewable energy technologies.展开更多
Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime go...Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime goal of carbon neutral. TiO_(2) based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H_(2) conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO_(2), non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti^(3+) generated by non-metal doping are located in the band-gap of TiO_(2), which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B^(3+), I^(7+), S^(4+)/S^(6+), P^(5+) can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO_(2) photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.展开更多
Lycium barbarum residue(LBR),a by-product of L.barbarum processing,is packed with bioactive components and can be potentially utilized as a feed additive in animal husbandry.However,the fundamental understanding of it...Lycium barbarum residue(LBR),a by-product of L.barbarum processing,is packed with bioactive components and can be potentially utilized as a feed additive in animal husbandry.However,the fundamental understanding of its effectiveness on livestock animals is still lacking,particularly in ruminants.To explore the effects of LBR on the growth performance,rumen fermentation parameters,ruminal microbes and metabolites of Tan sheep,sixteen fattening rams(aged 4 mon)were fed a basal diet(CON,n=8)or a basal diet supplemented with 5%LBR(LBR,n=8).The experiment lasted for 70 d,with 10 d adaptation period and 60 d treatment period.The results showed that the LBR enhanced the average daily feed intake,average daily gain(P<0.05),and ruminal total volatile fatty acids(P<0.01)while decreasing ammonia-nitrogen concentration and rumen pH value(P<0.05).Additionally,the LBR improved the relative abundances of Prevotella,Succiniclasticum,Ruminococcus,Coprococcus,Selenomonas,and Butyrivibrio(P<0.05)and reduced the relative abundances of Oscillospira and Succinivibrio(P<0.05).The LBR altered the ruminal metabolome(P<0.01)by increasing the abundances of ruminal metabolites involved in amino acids(e.g.,L-proline,L-phenylalanine,L-lysine,and L-tyrosine),pyrimidine metabolism(e.g.,uridine,uracil,and thymidine),and microbial protein synthesis(e.g.,xanthine and hypoxanthine).In conclusion,LBR had positive effects on the growth rate of Tan sheep as well as on rumen fermentation parameters,rumen microbiome and rumen metabolome.展开更多
The radical polymerization of maleic anhydride(MA),styrene(ST)with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano...The radical polymerization of maleic anhydride(MA),styrene(ST)with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica(MPNS)was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile,it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.展开更多
Traditional chrome tanning technology is still widely used today. In this technology, chrome shaving as well as chrome contained effluent in tanning and retanning processes is a big issue in the industry. Wet white ta...Traditional chrome tanning technology is still widely used today. In this technology, chrome shaving as well as chrome contained effluent in tanning and retanning processes is a big issue in the industry. Wet white tanning technology has been gaining in importance in recent years, but in general, the comprehensive performance of chrome-free tanned leather is not comparable with that of chrome tanned leather. In the present work, chrome-free tanning and chrome tanning are combined in a reversed procedure, which produces leather with chrome tanned leather quality without chrome tanned leather waste problems. In this procedure, a special amphoteric organic compound, no pickle, no salt chrome-free tanning agent TWT was used to tan delimed hides (no pickle) making wet white with shrinking temperature at 80-85 ~C. Then, new method called reversed tanning further process the wet white into chrome-tanned crust. In this reversed method, retanning, fatliquoring and coloring processes were carried out before chrome tanning. This technology eliminates chrome waste issue in tanning, shaving, post tanning processes. The chrome contained effluent is only concentrated in the last chrome tanning process. The leather made with this technology has complete conventional chrome-tanned leather quality. In this way, chrome leather quality without chrome waste problems was achieved. So, it is a new clean tanning technology.展开更多
Tetra-hydroxymethyl phosphonium chloride (THPC) has been considered as an important chrome-free tanning agent. To understand the THPC tanning mechanism, the structure, charge distribution, activity and tanning abili...Tetra-hydroxymethyl phosphonium chloride (THPC) has been considered as an important chrome-free tanning agent. To understand the THPC tanning mechanism, the structure, charge distribution, activity and tanning ability of each phosphorous compound in THPC tanning system were studied, by ^31p NMR, FT-IR spectroscopy, differential scanning calorimetry (DSC) and computational chemistry method, etc. When pH raised to 6.0, the decomposition of THPC would take place, which results in a production of free formaldehyde, tri-hydroxymethyl phosphonium (TrHP) and tri-hydroxymethyl phosphine oxide (TrHPO). At pH 9.0, THPC will be converted completely to TrHP and most TrHP is further oxidized into TrHPO. It is possible that, in reaction of phosphorous compounds and collagens, both P-C and C-O bonds would break simultaneously or individually. From molecular charge distribution and bond polar properties, it is deduced that, if P-C bonds break, the activity is in order of TrHPO 〉 THPC 〉 TrHE whereas if C--O bonds break, the order is TrHP 〉 THPC 〉 TrHPO. It is more possible that P--C bonds will break in reaction with collagen, and TrHPO may be more active in the THPC tanning system. The results of tanning and DSC also prove the above conclusion. Furthermore, the fact that the shrinkage temperature of THPC tanned leather was below 70℃ when basified to pH 5.0 or lower suggests that the hydroxymethyl groups of THPC and TrHP are less possible to combine directly with amino groups of collagen.展开更多
The mutant efficiency and hatching ratio are two key factors that significantly affect the construction of genome-modified mutant insects.In the construction of CRISPR/Cas9-mediated dsLmRNase2^(–/–)mutant locusts,we...The mutant efficiency and hatching ratio are two key factors that significantly affect the construction of genome-modified mutant insects.In the construction of CRISPR/Cas9-mediated dsLmRNase2^(–/–)mutant locusts,we found that the tanned eggs which experienced a 20-min contact with the oocyst exhibited a higher success rate compared to fresh newly-laid eggs that were less tanned.However,the heritable efficiency of the dsLmRNase2 deletion to the next generation G_(1 )progeny was similar between adults derived from the tanned or less tanned engineered eggs.Further,the similar effective mutant ratios in the normally developed eggs and G_(0) adults of tanned and less tanned eggs also indicated that tanning did not reduce the absolute mutation efficiency induced by CRISPR/Cas9.Moreover,we found that the syncytial division period,which was longer than the time for tanning,conferred a window period for microinjection treatment with efficient mutation in both tanned and less tanned eggs.We further found that tanned eggs exhibited a higher hatching rate due to a reduced infection rate following microinjection.Both the anti-pressure and ultrastructure analyses indicated that the tanned eggs contained compressed eggshells to withstand increased external pressure.In summary,tanned eggs possess stronger defense responses and higher efficiency of genome editing,providing an improved model for developing Cas9-mediated gene editing procedures in locusts.展开更多
With the increasing demand to reduce emissions and save energy,hydraulic reservoirs require new architecture to optimize their weight,space,and volume.Conventional open reservoirs are large,heavy,and easily polluted,a...With the increasing demand to reduce emissions and save energy,hydraulic reservoirs require new architecture to optimize their weight,space,and volume.Conventional open reservoirs are large,heavy,and easily polluted,and threaten the operation of hydraulic systems.A closed reservoir provides the advantages of small volume and light weight,compared to open reservoirs.In this study,a non-metallic pressure reservoir with variable volume is designed and manufactured for closed-circuit hydraulic systems.The reservoir housing is made of rubber,and the Mooney-Rivlin model is chosen based on the rubber strain properties.The FEA simulation for the reservoir is performed using ANSYS Workbench to obtain the structural stiffness.The major contribution is the establishment of mathematical models for this reservoir,including the volume equation changing with height,flow equation,and force balance equation,to explore the output characteristics of this reservoir.Based on these results,simulation models were built to analyze the output characteristics of the reservoir.Moreover,the test rig of a conventional hydraulic system was transformed into a closed-circuit asymmetric hydraulic system for the reservoir,and preliminary verification experiments were conducted on it.The results demonstrate that the designed reservoir can absorb and discharge oil and supercharge pump inlet to benefit system operation.The changes in the volume and pressure with displacements under different volume ratios and frequencies were obtained,which verified the accuracy of the mathematical models.Owing to its lightweight design and small volume,the reservoir can replace conventional open reservoirs,and this lays a foundation for future theoretical research on this reservoir.展开更多
In recent years, some important research indicated that the visible-light activity of photocatalysts could be enhanced via incorporating p-block non-metal elements into the lattice. In this paper, we investigated the ...In recent years, some important research indicated that the visible-light activity of photocatalysts could be enhanced via incorporating p-block non-metal elements into the lattice. In this paper, we investigated the electronic structures of pure and different non-metal (C, N, S, F, Cl, and Br) doped α-Bi2O3 using first-principles calculations based on the density functional theory. The band structures, the electronic densities of states, and the effective masses of electrons and holes for doped α-Bi2O3 were obtained and analyzed. The N and S dopings narrowed the band gap and reduced the effective mass of the carriers, which are beneficial for the photocatalytic performance. The theoretical predication was further confirmed by the experimental results.展开更多
The popularity of indoor tanning may be partly attributed to the addictive characteristics of tanning for some individuals.We aimed to determine the association between frequent indoor tanning,which we view as a sunog...The popularity of indoor tanning may be partly attributed to the addictive characteristics of tanning for some individuals.We aimed to determine the association between frequent indoor tanning,which we view as a sunogate for tanning addiction,and food addiction.A total of 67,910 women were included from the Nurses' Health Study II.In2005,we collected information on indoor tanning during high school/college and age 25-35 years,and calculated the average use of indoor tanning during these periods.Food addiction was defined as ≥3 clinically significant symptoms plus clinically significant impairment or distress,assessed in 2009 using a modified version of the Yale Food Addiction Scale.Totally 23.3%(15,822) of the participants reported indoor tanning at high school/college or age 25-35 years.A total of 5,557(8.2%) women met the criteria for food addiction.We observed a dose-response relationship between frequency of indoor tanning and the likelihood of food addiction(P_(trend)〈 0.0001),independent of depression,BMI,and other confounders.Compared with never indoor tanners,the odds ratio(95%confidence interval) of food addiction was 1.07(0.99-1.17) for average indoor tanning 1-2 times/year,1.25(1.09-1.43) for 3-5times/year,1.34(1.14-1.56) for 6-11 times/year,1.61(1.35-1.91) for 12-23 times/year,and 2.98(1.95-4.57) for 24 or more times/year.Frequent indoor tanning before or at early adulthood is associated with prevalence of food addiction at middle age.Our data support the addictive property of frequent indoor tanning,which may guide intervention strategies to curb indoor tanning and prevent skin cancer.展开更多
The leather manufacturing is traditionally responsible for high environmental pollution. Tannery effluent contains, indeed, large amounts of lime sludge, sulfides, acids, toxic metals salts, in particular chromium sal...The leather manufacturing is traditionally responsible for high environmental pollution. Tannery effluent contains, indeed, large amounts of lime sludge, sulfides, acids, toxic metals salts, in particular chromium salts, which are toxic, non-biodegradable and hardly disposable. For this reason, great research efforts are addressed to establish a significantly eco-sustainable and convenient business for companies and to produce high quality leather products. The replacement of current commercial chemical and toxic products with innovative natural/naturalized products and technologies in some crucial phases of the tanning cycle (mainly bating and defatting), can induce an eco-friendly reduction of the needed chromium amount. Leather samples, treated with innovative bating and defatting products and tanned by several different Cr contents, were characterized by SEM-EDS (Scanning Electron Microscopy equipped with Energy Dispersive X-Ray Spectroscopy) and TGA (Thermogravimetric Analysis). SEM-EDS was used to observe the surface and cross-section morphology and to provide a semi-quantitative elemental analysis, while TGA to evaluate the thermal stability and decomposition phases. The compatibility of the innovative products was demonstrated and the environmental impact of the process, performed by the effluents characterization, was effectively improved as a result of a 20% Cr lowering. The use of innovative products and the chromium reduction did not affect the thermal stability, leather morphology and not involve significant differences in the composition.展开更多
Xinji City, in the middle south of Hebei Province, has a tanning history of more than 400 years. The city boasted over 100 kinds of fur and leather products, over 300 workshops and shops and 24 foreign agencies in the...Xinji City, in the middle south of Hebei Province, has a tanning history of more than 400 years. The city boasted over 100 kinds of fur and leather products, over 300 workshops and shops and 24 foreign agencies in the early years of the Qing Dynasty (1644-1911). Since 1949, especially since 1981,the city’s tanning industry has witnessed a big leap. There are around 10, 000 tanning enterprises in the city with an annual industrial value of RMB 1.3 billion and an annual export value of US $展开更多
Skin lightening and tanning are two major areas dominating the market of skincare and cosmetic products. Though the demands are originated from two different communities, the two areas share a same goal—skin colour t...Skin lightening and tanning are two major areas dominating the market of skincare and cosmetic products. Though the demands are originated from two different communities, the two areas share a same goal—skin colour tuning. The known safe compounds with skin colour tuning activities are limited. In contrary, Chinese medicinal herb provides a pool of natural bioactive compounds, which have been used in Asian countries for long time and have been tested for its toxicity. Here, we demonstrate a high throughput screening platform for potential compounds usable for skin colour tuning. From 147 natural compounds, 26 of them showed potential in skin tanning functions by using the high throughput melanogenesis platform based on the melanogenesis assay on B16 melanocytes. Five of them promoted melanogenesis by over 50%. Moreover, apart from 1, 8-dihydroxyanthraquinone, the other four compounds showed enhancement effect on tyrosinase activity. From the result, the compounds increased the Vmax of tyrosinase without changing the Km in a dose-dependent manner. Thus, there should be no irreversible structural change of the enzyme. Definitely, this report contributes to the development of personalization in skincare and cosmetic products.展开更多
基金supported by the National Natural Science Foundation of China (52002412 and 22072186)the Natural Science Foundation of Guangdong Province (2021A1515010575)the Guangzhou Science and Technology Plan General Project (202102020862)。
文摘Developing high-performing non-noble transition metal catalysts for H_(2) evolution from chemical hydrogen storage materials is of great significance for the hydrogen economy system, yet challenging. Herein,we present for the first time that anomalous metastable hexagonal close-packed Ni nanoparticles induced by heteroatom N doping encapsulated in carbon(N-hcp-Ni/C) can exhibit admirable catalytic performance for ammonia borane(AB) dehydrogenation, prominently outperforming conventional fcc Ni counterpart with similar morphology and favorably presenting the state-of-the-art level.Comprehensive experimental and theoretical studies unravel that unusual hcp phase engineering of Ni together with N doping could induce charge redistribution and modulate electronic structure, thereby facilitating H_(2)O adsorption and expediting H_(2)O dissociation(rate-determining step). As a result, AB dehydrogenation can be substantially boosted with the assistance of N-hcp-Ni/C. Our proposed strategy highlights that unconventional crystal phase engineering coupled with non-metal heteroatom doping is a promising avenue to construct advanced transition metal catalysts for future renewable energy technologies.
基金supported by the National Natural Science Foundation of China(U1663225,21805280 and 21805220)the Youth Innovation Foundation of Xiamen City:3502Z20206085+4 种基金Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R52)The Opening Project of PCOSS,Xiamen University,201907the program of introducing Talents of discipline to Universities-111 Project(Grant No.B20002)the project“Depollut Air”of Interreg V France-Wallonie-Vlaanderenthe financial support from the China Scholarship Council(CSC)。
文摘Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime goal of carbon neutral. TiO_(2) based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H_(2) conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO_(2), non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti^(3+) generated by non-metal doping are located in the band-gap of TiO_(2), which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B^(3+), I^(7+), S^(4+)/S^(6+), P^(5+) can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO_(2) photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.
基金supported by the National Key Research and Development Program of China(2022YFD1300905)the National Natural Science Foundation of China(31960672)+3 种基金the Key Research and Development Program of Ningxia Hui Autonomous Region,China(2021BEF02020)the Top Discipline Construction Project of Pratacultural Science(NXYLXK2017A01)the Science and Technology Development Project of Jilin Province,China(20200201140JC)the Technology Cooperation High-Tech Industrialization Project of Jilin Province,China and the Chinese Academy of Sciences,(2022SYHZ0020).
文摘Lycium barbarum residue(LBR),a by-product of L.barbarum processing,is packed with bioactive components and can be potentially utilized as a feed additive in animal husbandry.However,the fundamental understanding of its effectiveness on livestock animals is still lacking,particularly in ruminants.To explore the effects of LBR on the growth performance,rumen fermentation parameters,ruminal microbes and metabolites of Tan sheep,sixteen fattening rams(aged 4 mon)were fed a basal diet(CON,n=8)or a basal diet supplemented with 5%LBR(LBR,n=8).The experiment lasted for 70 d,with 10 d adaptation period and 60 d treatment period.The results showed that the LBR enhanced the average daily feed intake,average daily gain(P<0.05),and ruminal total volatile fatty acids(P<0.01)while decreasing ammonia-nitrogen concentration and rumen pH value(P<0.05).Additionally,the LBR improved the relative abundances of Prevotella,Succiniclasticum,Ruminococcus,Coprococcus,Selenomonas,and Butyrivibrio(P<0.05)and reduced the relative abundances of Oscillospira and Succinivibrio(P<0.05).The LBR altered the ruminal metabolome(P<0.01)by increasing the abundances of ruminal metabolites involved in amino acids(e.g.,L-proline,L-phenylalanine,L-lysine,and L-tyrosine),pyrimidine metabolism(e.g.,uridine,uracil,and thymidine),and microbial protein synthesis(e.g.,xanthine and hypoxanthine).In conclusion,LBR had positive effects on the growth rate of Tan sheep as well as on rumen fermentation parameters,rumen microbiome and rumen metabolome.
文摘The radical polymerization of maleic anhydride(MA),styrene(ST)with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica(MPNS)was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile,it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.
文摘Traditional chrome tanning technology is still widely used today. In this technology, chrome shaving as well as chrome contained effluent in tanning and retanning processes is a big issue in the industry. Wet white tanning technology has been gaining in importance in recent years, but in general, the comprehensive performance of chrome-free tanned leather is not comparable with that of chrome tanned leather. In the present work, chrome-free tanning and chrome tanning are combined in a reversed procedure, which produces leather with chrome tanned leather quality without chrome tanned leather waste problems. In this procedure, a special amphoteric organic compound, no pickle, no salt chrome-free tanning agent TWT was used to tan delimed hides (no pickle) making wet white with shrinking temperature at 80-85 ~C. Then, new method called reversed tanning further process the wet white into chrome-tanned crust. In this reversed method, retanning, fatliquoring and coloring processes were carried out before chrome tanning. This technology eliminates chrome waste issue in tanning, shaving, post tanning processes. The chrome contained effluent is only concentrated in the last chrome tanning process. The leather made with this technology has complete conventional chrome-tanned leather quality. In this way, chrome leather quality without chrome waste problems was achieved. So, it is a new clean tanning technology.
基金the National Basic Research Program (2007CB616909)Startup Foundation of Applied Chemistry of the Key Discipline of Zhejiang University of Technology and Zhejiang Provincial Science and Technology Plan (2006C21107)
文摘Tetra-hydroxymethyl phosphonium chloride (THPC) has been considered as an important chrome-free tanning agent. To understand the THPC tanning mechanism, the structure, charge distribution, activity and tanning ability of each phosphorous compound in THPC tanning system were studied, by ^31p NMR, FT-IR spectroscopy, differential scanning calorimetry (DSC) and computational chemistry method, etc. When pH raised to 6.0, the decomposition of THPC would take place, which results in a production of free formaldehyde, tri-hydroxymethyl phosphonium (TrHP) and tri-hydroxymethyl phosphine oxide (TrHPO). At pH 9.0, THPC will be converted completely to TrHP and most TrHP is further oxidized into TrHPO. It is possible that, in reaction of phosphorous compounds and collagens, both P-C and C-O bonds would break simultaneously or individually. From molecular charge distribution and bond polar properties, it is deduced that, if P-C bonds break, the activity is in order of TrHPO 〉 THPC 〉 TrHE whereas if C--O bonds break, the order is TrHP 〉 THPC 〉 TrHPO. It is more possible that P--C bonds will break in reaction with collagen, and TrHPO may be more active in the THPC tanning system. The results of tanning and DSC also prove the above conclusion. Furthermore, the fact that the shrinkage temperature of THPC tanned leather was below 70℃ when basified to pH 5.0 or lower suggests that the hydroxymethyl groups of THPC and TrHP are less possible to combine directly with amino groups of collagen.
基金This work was supported by the National Natural Science Foundation of China(32070502,31730074,32072419 and 31501905).
文摘The mutant efficiency and hatching ratio are two key factors that significantly affect the construction of genome-modified mutant insects.In the construction of CRISPR/Cas9-mediated dsLmRNase2^(–/–)mutant locusts,we found that the tanned eggs which experienced a 20-min contact with the oocyst exhibited a higher success rate compared to fresh newly-laid eggs that were less tanned.However,the heritable efficiency of the dsLmRNase2 deletion to the next generation G_(1 )progeny was similar between adults derived from the tanned or less tanned engineered eggs.Further,the similar effective mutant ratios in the normally developed eggs and G_(0) adults of tanned and less tanned eggs also indicated that tanning did not reduce the absolute mutation efficiency induced by CRISPR/Cas9.Moreover,we found that the syncytial division period,which was longer than the time for tanning,conferred a window period for microinjection treatment with efficient mutation in both tanned and less tanned eggs.We further found that tanned eggs exhibited a higher hatching rate due to a reduced infection rate following microinjection.Both the anti-pressure and ultrastructure analyses indicated that the tanned eggs contained compressed eggshells to withstand increased external pressure.In summary,tanned eggs possess stronger defense responses and higher efficiency of genome editing,providing an improved model for developing Cas9-mediated gene editing procedures in locusts.
基金Supported by the National Key Research and Development Program of China(Grant No.2018YFB2000700)National Natural Science Foundation of China(Grant No.51890811).
文摘With the increasing demand to reduce emissions and save energy,hydraulic reservoirs require new architecture to optimize their weight,space,and volume.Conventional open reservoirs are large,heavy,and easily polluted,and threaten the operation of hydraulic systems.A closed reservoir provides the advantages of small volume and light weight,compared to open reservoirs.In this study,a non-metallic pressure reservoir with variable volume is designed and manufactured for closed-circuit hydraulic systems.The reservoir housing is made of rubber,and the Mooney-Rivlin model is chosen based on the rubber strain properties.The FEA simulation for the reservoir is performed using ANSYS Workbench to obtain the structural stiffness.The major contribution is the establishment of mathematical models for this reservoir,including the volume equation changing with height,flow equation,and force balance equation,to explore the output characteristics of this reservoir.Based on these results,simulation models were built to analyze the output characteristics of the reservoir.Moreover,the test rig of a conventional hydraulic system was transformed into a closed-circuit asymmetric hydraulic system for the reservoir,and preliminary verification experiments were conducted on it.The results demonstrate that the designed reservoir can absorb and discharge oil and supercharge pump inlet to benefit system operation.The changes in the volume and pressure with displacements under different volume ratios and frequencies were obtained,which verified the accuracy of the mathematical models.Owing to its lightweight design and small volume,the reservoir can replace conventional open reservoirs,and this lays a foundation for future theoretical research on this reservoir.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51072012 and 51272015)
文摘In recent years, some important research indicated that the visible-light activity of photocatalysts could be enhanced via incorporating p-block non-metal elements into the lattice. In this paper, we investigated the electronic structures of pure and different non-metal (C, N, S, F, Cl, and Br) doped α-Bi2O3 using first-principles calculations based on the density functional theory. The band structures, the electronic densities of states, and the effective masses of electrons and holes for doped α-Bi2O3 were obtained and analyzed. The N and S dopings narrowed the band gap and reduced the effective mass of the carriers, which are beneficial for the photocatalytic performance. The theoretical predication was further confirmed by the experimental results.
基金supported by Brown University Richard B.Salomon Faculty Research Award,Research Career Development Award of Dermatology Foundation,and Nurses' Health Study Ⅱ grant(UM1 CA176726)
文摘The popularity of indoor tanning may be partly attributed to the addictive characteristics of tanning for some individuals.We aimed to determine the association between frequent indoor tanning,which we view as a sunogate for tanning addiction,and food addiction.A total of 67,910 women were included from the Nurses' Health Study II.In2005,we collected information on indoor tanning during high school/college and age 25-35 years,and calculated the average use of indoor tanning during these periods.Food addiction was defined as ≥3 clinically significant symptoms plus clinically significant impairment or distress,assessed in 2009 using a modified version of the Yale Food Addiction Scale.Totally 23.3%(15,822) of the participants reported indoor tanning at high school/college or age 25-35 years.A total of 5,557(8.2%) women met the criteria for food addiction.We observed a dose-response relationship between frequency of indoor tanning and the likelihood of food addiction(P_(trend)〈 0.0001),independent of depression,BMI,and other confounders.Compared with never indoor tanners,the odds ratio(95%confidence interval) of food addiction was 1.07(0.99-1.17) for average indoor tanning 1-2 times/year,1.25(1.09-1.43) for 3-5times/year,1.34(1.14-1.56) for 6-11 times/year,1.61(1.35-1.91) for 12-23 times/year,and 2.98(1.95-4.57) for 24 or more times/year.Frequent indoor tanning before or at early adulthood is associated with prevalence of food addiction at middle age.Our data support the addictive property of frequent indoor tanning,which may guide intervention strategies to curb indoor tanning and prevent skin cancer.
文摘The leather manufacturing is traditionally responsible for high environmental pollution. Tannery effluent contains, indeed, large amounts of lime sludge, sulfides, acids, toxic metals salts, in particular chromium salts, which are toxic, non-biodegradable and hardly disposable. For this reason, great research efforts are addressed to establish a significantly eco-sustainable and convenient business for companies and to produce high quality leather products. The replacement of current commercial chemical and toxic products with innovative natural/naturalized products and technologies in some crucial phases of the tanning cycle (mainly bating and defatting), can induce an eco-friendly reduction of the needed chromium amount. Leather samples, treated with innovative bating and defatting products and tanned by several different Cr contents, were characterized by SEM-EDS (Scanning Electron Microscopy equipped with Energy Dispersive X-Ray Spectroscopy) and TGA (Thermogravimetric Analysis). SEM-EDS was used to observe the surface and cross-section morphology and to provide a semi-quantitative elemental analysis, while TGA to evaluate the thermal stability and decomposition phases. The compatibility of the innovative products was demonstrated and the environmental impact of the process, performed by the effluents characterization, was effectively improved as a result of a 20% Cr lowering. The use of innovative products and the chromium reduction did not affect the thermal stability, leather morphology and not involve significant differences in the composition.
文摘Xinji City, in the middle south of Hebei Province, has a tanning history of more than 400 years. The city boasted over 100 kinds of fur and leather products, over 300 workshops and shops and 24 foreign agencies in the early years of the Qing Dynasty (1644-1911). Since 1949, especially since 1981,the city’s tanning industry has witnessed a big leap. There are around 10, 000 tanning enterprises in the city with an annual industrial value of RMB 1.3 billion and an annual export value of US $
文摘Skin lightening and tanning are two major areas dominating the market of skincare and cosmetic products. Though the demands are originated from two different communities, the two areas share a same goal—skin colour tuning. The known safe compounds with skin colour tuning activities are limited. In contrary, Chinese medicinal herb provides a pool of natural bioactive compounds, which have been used in Asian countries for long time and have been tested for its toxicity. Here, we demonstrate a high throughput screening platform for potential compounds usable for skin colour tuning. From 147 natural compounds, 26 of them showed potential in skin tanning functions by using the high throughput melanogenesis platform based on the melanogenesis assay on B16 melanocytes. Five of them promoted melanogenesis by over 50%. Moreover, apart from 1, 8-dihydroxyanthraquinone, the other four compounds showed enhancement effect on tyrosinase activity. From the result, the compounds increased the Vmax of tyrosinase without changing the Km in a dose-dependent manner. Thus, there should be no irreversible structural change of the enzyme. Definitely, this report contributes to the development of personalization in skincare and cosmetic products.