Though widely used in our daily lives,volatile methylsiloxanes and derivatives are emerging contaminants and becoming a high-priority environment and public health concern.Developing effective sorbent materials can re...Though widely used in our daily lives,volatile methylsiloxanes and derivatives are emerging contaminants and becoming a high-priority environment and public health concern.Developing effective sorbent materials can remove siloxanes in a cost-effective manner.Herein,by means of Grand Canonical Monte Carlo(GCMC)simulations,we evaluated the potentials of the recently proposed 68 stable zeolite-templated carbons(ZTCs)(PNAS 2018,115,E8116-E8124)for the removal of four linear methylsiloxanes and derivatives as well as two cyclic methylsiloxanes by the calculated average loading and average adsorption energy values.Four ZTCs,namely ISV,FAU1,FAU3,and H8326836,were identified with the top 50%adsorption performance toward all the six targeted contaminants,which outperform activated carbons.Further first principles computations revealed that steric hindrance,electrostatic interactions(further enhanced by charge transfer),and CH-p interactions account for the outstanding adsorption performance of these ZTCs.This work provides a quick procedure to computationally screen promising ZTCs for siloxane removal,and help guide future experimental and theoretical investigations.展开更多
Mono-chlorinated products of cyclic volatile methylsiloxanes(cVMS),i.e.,Monochlormethylheptamethylcyclotetrasiloxane[D3D(CH_(2)Cl)],monochlormethylnonamethylcyclopentasiloxane[D4D(CH_(2)Cl)],and monochlormethylundemet...Mono-chlorinated products of cyclic volatile methylsiloxanes(cVMS),i.e.,Monochlormethylheptamethylcyclotetrasiloxane[D3D(CH_(2)Cl)],monochlormethylnonamethylcyclopentasiloxane[D4D(CH_(2)Cl)],and monochlormethylundemethylcyclohexasiloxane[D5D(CH_(2)Cl)],were detected in water[<LOQ(Limit of quantitation)-86.3 ng/L,df(detection frequency)=23%-38%,n=112]and sediment samples[<LOQ-504 ng/g dw(dry weight),df=33%-38%,n=112]from 16 lakes located in Shengli oilfield of China,and had apparent increasing trends(31%-34%per annum)in sediments during Year 2014-2020.Simulated experiments showed that chloro-cVMS in sediment-water system had approximately 1.7-2.0 times slower elimination rates than parent cVMS.More specifically,compared with those of parent cVMS,volatilization(86-2558 days)and hydrolysis(135-549 days)half-lives of chlorocVMS were respectively 1.3-2.0 and 1.8-2.1 times longer.In two species of freshwater mussels(n=1050)collected from six lakes,concentrations of chloro-cVMS ranged from 9.8-998 ng/g dw in Anodonta woodiana and 8.4-970 ng/g dw in Corbicula fluminea.Compared with parent cVMS,chloro-cVMS had 1.1-1.5 times larger biota-sediment accumulation factors(2.1-3.0)and 1.1-1.7 times longer half-lives(13-42 days).Their stronger persistence in sediment and bioaccumulation in freshwatermussels suggested that environmental emission,distribution and risks of chloro-cVMS deserve further attention.展开更多
Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cy...Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cyclic methylsiloxanes(D4–D6) and twelve linear methylsiloxanes(L5–L16) in mollusks collected from seven cities along the Bohai Sea. D4–D6(df = 71%–81%) and L8–L16(df = 32%–40%) were frequently detectable in the mollusk samples, while L5–L7 were not found in any mollusk samples. Cyclic methylsiloxanes(D4–D6) were found in mollusks with the mean concentrations of 15.7 ± 12.3 ng/g ww for D4,24.6 ± 15.8 ng/g ww for D5 and 34.0 ± 23.0 ng/g ww for D6. Among the seven sampling cities, the cyclic methylsiloxanes were predominant in mollusks, with the total cyclic methylsiloxanes(sum of D4–D6, ∑ CMS) accounting for 74.2%–80.7% of the total methylsiloxanes. ∑ CMS along the coastline demonstrated a clear gradient, with the highest concentrations in mollusks at the sampling sites located in the western part of the Bohai Sea and the lowest concentrations in mollusks from cities located in the eastern part of the Bohai Sea. The biota-sediment accumulation factors for cyclic methylsiloxanes(D4–D6) and linear methylsiloxanes(L8–L16) were estimated as 0.42 ± 0.06–0.53 ± 0.06 and0.13 ± 0.03–0.19 ± 0.05, respectively.展开更多
Polymer electrolytes based on poly （methylsiloxane-g-ethylene oxide） and LiClO<sub>4</sub> have been prepared. The network films crosslinked by a crosslinking agent are found to exhibit a considerably hi...Polymer electrolytes based on poly （methylsiloxane-g-ethylene oxide） and LiClO<sub>4</sub> have been prepared. The network films crosslinked by a crosslinking agent are found to exhibit a considerably high ionic conductivity of about 10<sup>-4</sup> Scm<sup>-1</sup> at room temperature and have good flexibility.展开更多
In this paper, we report an antibody functionalized microimmunopreci- pitation(μIP) method used for enrich lowabundant post-translational modified(PTM) proteins. The device is fabricated by inert, nontoxic and dispos...In this paper, we report an antibody functionalized microimmunopreci- pitation(μIP) method used for enrich lowabundant post-translational modified(PTM) proteins. The device is fabricated by inert, nontoxic and disposable polydimethylsiloxane(PDMS) using a silane-based chemical modification protocol, which yield antibody-terminated PDMS surfaces. In this study, the μIP device is specifically designed for the purification of carbonylated protein, a representative example here to illustrate the potential applications for any other PTMs, which could be immuno-tagged by specific antibodies. The test model in vitro oxidized bovine serum albumin(BSA) was first derivitized by dinitrophenylhydrazide(DNPH) and then captured by the anti-DNP immobilized on this μIP device. The surface functional group mapping was systematically analyzed and validated by fluorescence microscopy. Quantitative study of DNP-derivatized carbonylated protein capture recovery and elution efficiency of the device was also studied. We also envision that this proteome enrichment μIP device can be assembled with other lab-on-a-chip components, such as microelectrophoresis or micro-chromatographic devices for follow-up protein analysis. This selective enrichment of modified proteins greatly facilitates the study of low abundant protein biomarkers discovery.展开更多
基金financially supported by NASA(Grant80NSSC17M0047)NSF(REU 1757365)+3 种基金partially supported by an Institutional Development Award(IDeA)INBRE Grant Number P20GM103475 from the National Institute of General Medical Sciences(NIGMS)a component of the National Institute of Health(NIH)the Bioinformatics Research Core of the INBREsupported by the office of science of the U.S.DOE under Contract No.DE-AC0500OR22750 and DE-AC02-05CH11231。
文摘Though widely used in our daily lives,volatile methylsiloxanes and derivatives are emerging contaminants and becoming a high-priority environment and public health concern.Developing effective sorbent materials can remove siloxanes in a cost-effective manner.Herein,by means of Grand Canonical Monte Carlo(GCMC)simulations,we evaluated the potentials of the recently proposed 68 stable zeolite-templated carbons(ZTCs)(PNAS 2018,115,E8116-E8124)for the removal of four linear methylsiloxanes and derivatives as well as two cyclic methylsiloxanes by the calculated average loading and average adsorption energy values.Four ZTCs,namely ISV,FAU1,FAU3,and H8326836,were identified with the top 50%adsorption performance toward all the six targeted contaminants,which outperform activated carbons.Further first principles computations revealed that steric hindrance,electrostatic interactions(further enhanced by charge transfer),and CH-p interactions account for the outstanding adsorption performance of these ZTCs.This work provides a quick procedure to computationally screen promising ZTCs for siloxane removal,and help guide future experimental and theoretical investigations.
基金supported by the National Key Research and Development Program of China (No.2019YFC1804501)the National Natural Science Foundation of China (Nos.22036007,21876189, 21607112)+1 种基金the Youth Innovation Promotion Association CAS, China Postdoctoral Science Foundation (No.2021M693320)the Tianjin Fundamental Research Program of the Tianjin Committee of Science and Technology (No.19JCQNJC08200)。
文摘Mono-chlorinated products of cyclic volatile methylsiloxanes(cVMS),i.e.,Monochlormethylheptamethylcyclotetrasiloxane[D3D(CH_(2)Cl)],monochlormethylnonamethylcyclopentasiloxane[D4D(CH_(2)Cl)],and monochlormethylundemethylcyclohexasiloxane[D5D(CH_(2)Cl)],were detected in water[<LOQ(Limit of quantitation)-86.3 ng/L,df(detection frequency)=23%-38%,n=112]and sediment samples[<LOQ-504 ng/g dw(dry weight),df=33%-38%,n=112]from 16 lakes located in Shengli oilfield of China,and had apparent increasing trends(31%-34%per annum)in sediments during Year 2014-2020.Simulated experiments showed that chloro-cVMS in sediment-water system had approximately 1.7-2.0 times slower elimination rates than parent cVMS.More specifically,compared with those of parent cVMS,volatilization(86-2558 days)and hydrolysis(135-549 days)half-lives of chlorocVMS were respectively 1.3-2.0 and 1.8-2.1 times longer.In two species of freshwater mussels(n=1050)collected from six lakes,concentrations of chloro-cVMS ranged from 9.8-998 ng/g dw in Anodonta woodiana and 8.4-970 ng/g dw in Corbicula fluminea.Compared with parent cVMS,chloro-cVMS had 1.1-1.5 times larger biota-sediment accumulation factors(2.1-3.0)and 1.1-1.7 times longer half-lives(13-42 days).Their stronger persistence in sediment and bioaccumulation in freshwatermussels suggested that environmental emission,distribution and risks of chloro-cVMS deserve further attention.
基金supported by the National Natural Science Foundation of China (Nos.21537004,21777182,21621064,21407159)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB14010201)
文摘Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cyclic methylsiloxanes(D4–D6) and twelve linear methylsiloxanes(L5–L16) in mollusks collected from seven cities along the Bohai Sea. D4–D6(df = 71%–81%) and L8–L16(df = 32%–40%) were frequently detectable in the mollusk samples, while L5–L7 were not found in any mollusk samples. Cyclic methylsiloxanes(D4–D6) were found in mollusks with the mean concentrations of 15.7 ± 12.3 ng/g ww for D4,24.6 ± 15.8 ng/g ww for D5 and 34.0 ± 23.0 ng/g ww for D6. Among the seven sampling cities, the cyclic methylsiloxanes were predominant in mollusks, with the total cyclic methylsiloxanes(sum of D4–D6, ∑ CMS) accounting for 74.2%–80.7% of the total methylsiloxanes. ∑ CMS along the coastline demonstrated a clear gradient, with the highest concentrations in mollusks at the sampling sites located in the western part of the Bohai Sea and the lowest concentrations in mollusks from cities located in the eastern part of the Bohai Sea. The biota-sediment accumulation factors for cyclic methylsiloxanes(D4–D6) and linear methylsiloxanes(L8–L16) were estimated as 0.42 ± 0.06–0.53 ± 0.06 and0.13 ± 0.03–0.19 ± 0.05, respectively.
文摘Polymer electrolytes based on poly （methylsiloxane-g-ethylene oxide） and LiClO<sub>4</sub> have been prepared. The network films crosslinked by a crosslinking agent are found to exhibit a considerably high ionic conductivity of about 10<sup>-4</sup> Scm<sup>-1</sup> at room temperature and have good flexibility.
基金National Institutes of Health and the National Center for Research Resources grant number: P20RR01645 and NIH grant # DK44510
文摘In this paper, we report an antibody functionalized microimmunopreci- pitation(μIP) method used for enrich lowabundant post-translational modified(PTM) proteins. The device is fabricated by inert, nontoxic and disposable polydimethylsiloxane(PDMS) using a silane-based chemical modification protocol, which yield antibody-terminated PDMS surfaces. In this study, the μIP device is specifically designed for the purification of carbonylated protein, a representative example here to illustrate the potential applications for any other PTMs, which could be immuno-tagged by specific antibodies. The test model in vitro oxidized bovine serum albumin(BSA) was first derivitized by dinitrophenylhydrazide(DNPH) and then captured by the anti-DNP immobilized on this μIP device. The surface functional group mapping was systematically analyzed and validated by fluorescence microscopy. Quantitative study of DNP-derivatized carbonylated protein capture recovery and elution efficiency of the device was also studied. We also envision that this proteome enrichment μIP device can be assembled with other lab-on-a-chip components, such as microelectrophoresis or micro-chromatographic devices for follow-up protein analysis. This selective enrichment of modified proteins greatly facilitates the study of low abundant protein biomarkers discovery.
