New magnetic air-stable nanogranular Fe thin films of 10 ± 1.2 nm thickness were prepared onto silicon wafers at 150℃ under inert atmosphere by controlled Chemical Vapor Deposition (CVD) of triiron dodecacarbony...New magnetic air-stable nanogranular Fe thin films of 10 ± 1.2 nm thickness were prepared onto silicon wafers at 150℃ under inert atmosphere by controlled Chemical Vapor Deposition (CVD) of triiron dodecacarbonyl (Fe3(CO)12). These thin films, composed of sintered elemental Fe nanoparticles of 4.1 ± 0.7 nm diameter, are protected from air oxidation by a very thin carbon layer. The saturation magnetization of these thin Fe coatings was found to be close to that of bulk iron. The electrical resistivity behavior of the ferromagnetic thin films is similar to that of a semiconductor. In the present manuscript, these Fe thin coatings on Si wafers have been used as a catalyst for synthesizing crystalline carbon nanotubes (CNTs), by CVD using ethylene as a carbon precursor.展开更多
Fluorescent probes with high signal/background ratio are needed for hybridization assays. Hence, the chromophore of green fluorescent protein (GFP), 4-hydroxybenzylidene-imidazolinone (HBI), was targeted as a potentia...Fluorescent probes with high signal/background ratio are needed for hybridization assays. Hence, the chromophore of green fluorescent protein (GFP), 4-hydroxybenzylidene-imidazolinone (HBI), was targeted as a potential fluorescent intercalator. For producing a building block for fluorescent oligonucleotide probes, 2'-deoxyuridine (dU) was conjugated with HBI via a flexible carbon-spacer. dUHBI conjugates highly fluoresce in glycerol (λem 460 nm,Φ 0.31), and are 109-fold more emissive than in methanol, implying the potential of dUHBI-labeled oligonucleotides as probes for hybridization assays.展开更多
The development of chiral auxiliary-controlled asymmetric synthesis has been receiving increasing interest in recent yearsfi,2] Various chiral auxiliary reagents have been observed[3] and a lot of results showed t... The development of chiral auxiliary-controlled asymmetric synthesis has been receiving increasing interest in recent yearsfi,2] Various chiral auxiliary reagents have been observed[3] and a lot of results showed that variation of the chiral auxiliary could influence asymmetric induction. Recently, it has been reported the reaction of the aminated sulfones as a remote chiral auxiliary with α,β-unsaturated carbonyl compounds.[4] Here we would like to report the preparation of amino acid ester sulfones as new remote asymmetrical induced reagents and their reactions with α,β-unsaturated esters.……展开更多
Imidazoles as pharmaceutical agents are widely used and investigated. A series of bis-azoles were prepared fromimidazole and its analogues and dibromides obtained according to similar procedures of literatures. [1... Imidazoles as pharmaceutical agents are widely used and investigated. A series of bis-azoles were prepared fromimidazole and its analogues and dibromides obtained according to similar procedures of literatures. [1 ～ 4]……展开更多
Oxygen reduction reaction(ORR)is considered the bottleneck reaction in fuel cells.Its sluggish kinetics requires the use of scarce and expensive platinum group metal(PGM)catalysts.Significant efforts have been investe...Oxygen reduction reaction(ORR)is considered the bottleneck reaction in fuel cells.Its sluggish kinetics requires the use of scarce and expensive platinum group metal(PGM)catalysts.Significant efforts have been invested in trying to find a PGM-free catalyst to replace Pt for this reaction or reduce its loadings.One interesting family of materials that has shown great promise in doing so is aerogels,which are based on covalent frameworks.The aerogels’high surface area and porosity enable good mass transport and high catalyst utilization that is expected to lower PGM loadings or replacing them completely.This review summarizes recent research in this field,introducing methods of using aerogels as cathodes for ORR,from carbon to metal aerogels.The catalytic sites vary from nanoparticles to atomically dispersed metal ions embedded in carbon aerogels that form all-in-one platform which can serve as both the support and the catalyst.展开更多
Layered lithium intercalating transition metal oxides are promising cathode materials for Li-ion batteries.Here,we scrutinize the recently developed strongly constrained and appropriately normed(SCAN)density functiona...Layered lithium intercalating transition metal oxides are promising cathode materials for Li-ion batteries.Here,we scrutinize the recently developed strongly constrained and appropriately normed(SCAN)density functional method to study structural,magnetic,and electrochemical properties of prototype cathode materials LiNiO_(2),LiCoO_(2),and LiMnO_(2) at different Li-intercalation limits.We show that SCAN outperforms earlier popular functional combinations,providing results in considerably better agreement with experiment without the use of Hubbard parameters,and dispersion corrections are found to have a small effect.In particular,SCAN fares better than Perdew–Burke–Ernzerhof(PBE)functional for the prediction of band-gaps and absolute voltages,better than PBE+U for the electronic density of states and voltage profiles,and better than both PBE and PBE+U for electron densities and in operando lattice parameters.This overall better performance of SCAN may be ascribed to improved treatment of localized states and a better description of short-range dispersion interactions.展开更多
RNA plays important roles as a gene-silencing agent, a therapeutic agent for clinical treatment, and in the differentiation, proliferation, and development of cells. However, RNA is very difficult to work with due to ...RNA plays important roles as a gene-silencing agent, a therapeutic agent for clinical treatment, and in the differentiation, proliferation, and development of cells. However, RNA is very difficult to work with due to its sensitivity and fragility. Another obstacle in using RNA for gene delivery/silencing is its negative charge, which causes its repulsion by cell membranes, which are also negatively charged. Our recent study showed that miR-125b is upregulated in glioblastoma （GMB） and plays an oncogenic role in GMB cells by promoting cell proliferation and inhibiting apoptosis. Endogenous miR-125b can be blocked by transfection of its antisense RNA molecule, miR-125b antisense （miR-125b-AS）. Thus, miR- 125b-AS can be developed as an RNA-based agent for cancer treatment. However, instability during storage and difficulty in delivery into cells has limited the use of RNA-based therapies thus far. In the current work, we demonstrate a short and simple one-step technique for the preparation of positively charged RNA nanospheres （miR-125b-RNS and miR-125b-AS-RNS） coated with a bioavailable polymer, polyethylenimine （PEI）. These RNA nanospheres are able to penetrate the cell directly without the use of liposomes. Our study confirmed that converting miR-125b and miR-125b-AS into nanospheres is a viable approach for storing RNA. In addition, this study provides evidence that PEI-coated RNA nanospheres have the potential to be used as a novel class of anticancer a^ents.展开更多
Dye-sensitized solar cells (DSSCs) are cost-effective,sustainable,and versatile electricity producers,allowing them to be incorporated into a variety of devices.In this work,we explore the usage of pharmacophore model...Dye-sensitized solar cells (DSSCs) are cost-effective,sustainable,and versatile electricity producers,allowing them to be incorporated into a variety of devices.In this work,we explore the usage of pharmacophore modeling to identify metal-free dyes for DSSCs by means of virtual screening.Pharmacophore models were built based on experimentally tested sensitizers.Virtual screening was performed against a large dataset of commercially available compounds taken from the ZINC15 library and identified multiple virtual hits.A subset of these hits was subjected to DFT and time-dependent-DFT calculations leading to the identification of two compounds,TSC6 and ASC5,with appropriate molecular orbitals energies,favorable localization,and reasonable absorption UV–vis spectra.These results suggest that pharmacophore models,traditionally used in drug discovery and lead optimization,successfully predicted electronic properties,which are in agreement with the theoretical requirements for sensitizers.Such models may therefore find additional usages as modeling tools in materials sciences.展开更多
文摘New magnetic air-stable nanogranular Fe thin films of 10 ± 1.2 nm thickness were prepared onto silicon wafers at 150℃ under inert atmosphere by controlled Chemical Vapor Deposition (CVD) of triiron dodecacarbonyl (Fe3(CO)12). These thin films, composed of sintered elemental Fe nanoparticles of 4.1 ± 0.7 nm diameter, are protected from air oxidation by a very thin carbon layer. The saturation magnetization of these thin Fe coatings was found to be close to that of bulk iron. The electrical resistivity behavior of the ferromagnetic thin films is similar to that of a semiconductor. In the present manuscript, these Fe thin coatings on Si wafers have been used as a catalyst for synthesizing crystalline carbon nanotubes (CNTs), by CVD using ethylene as a carbon precursor.
文摘Fluorescent probes with high signal/background ratio are needed for hybridization assays. Hence, the chromophore of green fluorescent protein (GFP), 4-hydroxybenzylidene-imidazolinone (HBI), was targeted as a potential fluorescent intercalator. For producing a building block for fluorescent oligonucleotide probes, 2'-deoxyuridine (dU) was conjugated with HBI via a flexible carbon-spacer. dUHBI conjugates highly fluoresce in glycerol (λem 460 nm,Φ 0.31), and are 109-fold more emissive than in methanol, implying the potential of dUHBI-labeled oligonucleotides as probes for hybridization assays.
基金Project supported by the Sciences and Technology Committee of Chongqing, the Personnel Department of China, the National Natural Science Foundation of China, and the Fred and Barbara Kort Sino-Israel Postdoctoral Fellowship Program.
文摘 The development of chiral auxiliary-controlled asymmetric synthesis has been receiving increasing interest in recent yearsfi,2] Various chiral auxiliary reagents have been observed[3] and a lot of results showed that variation of the chiral auxiliary could influence asymmetric induction. Recently, it has been reported the reaction of the aminated sulfones as a remote chiral auxiliary with α,β-unsaturated carbonyl compounds.[4] Here we would like to report the preparation of amino acid ester sulfones as new remote asymmetrical induced reagents and their reactions with α,β-unsaturated esters.……
基金Project supported by the National Natural Science Foundation of China, the Personnel Department of China, the China Postdoctoral Science Foundation, Sciences and Technology Committee of Chongqing, and the Fred and Barbara Kort Sino-Israel Postdoctoral Fellowship Program as well as the Marcus Center of Medicinal Chemistry.
文摘 Imidazoles as pharmaceutical agents are widely used and investigated. A series of bis-azoles were prepared fromimidazole and its analogues and dibromides obtained according to similar procedures of literatures. [1 ～ 4]……
基金Israeli Ministry of Energy,Grant/Award Numbers:221-11-058,219-11-132Israeli Science Foundation,Grant/Award Number:238/21The Israeli Ministry of Science and Technology,Grant/Award Number:3-16020。
文摘Oxygen reduction reaction(ORR)is considered the bottleneck reaction in fuel cells.Its sluggish kinetics requires the use of scarce and expensive platinum group metal(PGM)catalysts.Significant efforts have been invested in trying to find a PGM-free catalyst to replace Pt for this reaction or reduce its loadings.One interesting family of materials that has shown great promise in doing so is aerogels,which are based on covalent frameworks.The aerogels’high surface area and porosity enable good mass transport and high catalyst utilization that is expected to lower PGM loadings or replacing them completely.This review summarizes recent research in this field,introducing methods of using aerogels as cathodes for ORR,from carbon to metal aerogels.The catalytic sites vary from nanoparticles to atomically dispersed metal ions embedded in carbon aerogels that form all-in-one platform which can serve as both the support and the catalyst.
文摘Layered lithium intercalating transition metal oxides are promising cathode materials for Li-ion batteries.Here,we scrutinize the recently developed strongly constrained and appropriately normed(SCAN)density functional method to study structural,magnetic,and electrochemical properties of prototype cathode materials LiNiO_(2),LiCoO_(2),and LiMnO_(2) at different Li-intercalation limits.We show that SCAN outperforms earlier popular functional combinations,providing results in considerably better agreement with experiment without the use of Hubbard parameters,and dispersion corrections are found to have a small effect.In particular,SCAN fares better than Perdew–Burke–Ernzerhof(PBE)functional for the prediction of band-gaps and absolute voltages,better than PBE+U for the electronic density of states and voltage profiles,and better than both PBE and PBE+U for electron densities and in operando lattice parameters.This overall better performance of SCAN may be ascribed to improved treatment of localized states and a better description of short-range dispersion interactions.
文摘RNA plays important roles as a gene-silencing agent, a therapeutic agent for clinical treatment, and in the differentiation, proliferation, and development of cells. However, RNA is very difficult to work with due to its sensitivity and fragility. Another obstacle in using RNA for gene delivery/silencing is its negative charge, which causes its repulsion by cell membranes, which are also negatively charged. Our recent study showed that miR-125b is upregulated in glioblastoma （GMB） and plays an oncogenic role in GMB cells by promoting cell proliferation and inhibiting apoptosis. Endogenous miR-125b can be blocked by transfection of its antisense RNA molecule, miR-125b antisense （miR-125b-AS）. Thus, miR- 125b-AS can be developed as an RNA-based agent for cancer treatment. However, instability during storage and difficulty in delivery into cells has limited the use of RNA-based therapies thus far. In the current work, we demonstrate a short and simple one-step technique for the preparation of positively charged RNA nanospheres （miR-125b-RNS and miR-125b-AS-RNS） coated with a bioavailable polymer, polyethylenimine （PEI）. These RNA nanospheres are able to penetrate the cell directly without the use of liposomes. Our study confirmed that converting miR-125b and miR-125b-AS into nanospheres is a viable approach for storing RNA. In addition, this study provides evidence that PEI-coated RNA nanospheres have the potential to be used as a novel class of anticancer a^ents.
文摘Dye-sensitized solar cells (DSSCs) are cost-effective,sustainable,and versatile electricity producers,allowing them to be incorporated into a variety of devices.In this work,we explore the usage of pharmacophore modeling to identify metal-free dyes for DSSCs by means of virtual screening.Pharmacophore models were built based on experimentally tested sensitizers.Virtual screening was performed against a large dataset of commercially available compounds taken from the ZINC15 library and identified multiple virtual hits.A subset of these hits was subjected to DFT and time-dependent-DFT calculations leading to the identification of two compounds,TSC6 and ASC5,with appropriate molecular orbitals energies,favorable localization,and reasonable absorption UV–vis spectra.These results suggest that pharmacophore models,traditionally used in drug discovery and lead optimization,successfully predicted electronic properties,which are in agreement with the theoretical requirements for sensitizers.Such models may therefore find additional usages as modeling tools in materials sciences.
