The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts c...The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.展开更多
Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are...Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are highly susceptible to framework charge,which plays a significant role in selective adsorption.Currently,ionic porous frameworks can be divided into two types.One of them is composed of a charged backbone and counter ions.The framework with zwitterionic channels is another type.It is composed of regular and alternating arrangements of cationic and anionic building units.Herein,we report a hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}_nwith 1D channel exhibits unique adsorption selectivity for Ar against N_(2)and CO_(2).Density functional theory(DFT)results suggest that CO_(2)cannot be adsorbed by HIF at the experimental temperature due to a positive adsorption free energy.In addition,due to a relatively large diffusion barrier at 77 K,N_(2)molecules hardly diffuse in HIF channels,while Ar has a negligible diffusion barrier.The unique net positively-charged space in the channel is the key to the unusual phenomena,based on DFT simulations and structural analysis.The findings in this work proposes the new adsorption mechanism and provides unique perspective for special separation applications,such as isotope and noble gasses separations.展开更多
BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with...BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with ASD display marked food selectivity,often restricting themselves to a narrow range of foods.The problems associated with feeding children with ASD can vary widely,from mild cases that pose no immediate health risks,to more severe situations with a risk of mal-nutrition or,conversely,overeating.This scoping review aims to provide an in-depth overview of the frequency,nature and factors related to food selectivity in children with autism.AIM To comprehensively review the literature on food selectivity in ASD.METHODS A systematic review of the literature was conducted using the PubMed,Web of Science and EBSCO databases,to identify articles published in English from 2014 until 2024.Studies on a sample diagnosed with ASD and food selectivity were included.The selected databases were chosen for their broad coverage of the scientific literature.These databases represent reliable sources of high-quality articles,ensuring a comprehensive and up-to-date search.RESULTS We evaluated 222 studies on food selectivity in autism,from which duplicates were removed and unrelated titles were filtered out.Finally,9 articles were included in the review.Five articles provide a general overview of the phenomenon,analysing its nature and factors.Two studies delve into sensory sensitivity,in particular the impact of food textures,tastes and smells.Finally,two studies focus on problem behaviour during mealtimes.CONCLUSION Children with ASD have greater food selectivity than the neurotypical population.The diet should contain a greater variety of fruit,vegetables,yoghurt,while reducing the consumption of rice and pasta.展开更多
Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we d...Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles.展开更多
Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidatio...Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidation offers a more sustainable and milder alternative;however,it faces challenges such as aldehyde overoxidation and susceptibility to base-catalyzed Cannizzaro disproportionation.Electrochemical glycerol oxidation to glyceraldehyde is a representative example,which typically requires precious metal-based electrocatalysts but still suffers from low selectivity and activity.Here,we report a metal-free oxidation strategy mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl.By systematically investigating the redox thermodynamics and kinetics of TEMPO across a broad pH range,we construct a Pourbaix diagram and elucidate the relative kinetics of each reaction step.These insights allow us to explain the anomalously high apparent Faradaic efficiency(~200%)observed under acidic conditions,and identify neutral media as the optimal environment for selective glyceraldehyde production.Under optimized conditions,our system achieves a glyceraldehyde Faradaic efficiency exceeding 93%and a partial current density of 23.3 mA cm^(-2)at 0.57 V—more than doubling the performance of the best reported precious metal-based systems.Furthermore,the versatility of this strategy extends to the selective oxidation of other primary alcohols to their corresponding aldehydes with near-unity selectivity.展开更多
Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but ful...Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3).展开更多
The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsor...The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsorbing REEs onto microalgae,but biomass immobilization and light delivery challenges remain.It was recently shown that REEs biosorb 160% more on algal biofilms than suspended biomass due to the extracellular polymeric substance(EPS) matrix that grows abundantly in biofilms.In this work,we present findings on biosorption selectivity for different REEs in sulfate solutions.The maximum adsorption capacities of Euglena mutabilis suspensions and biofilms were determined for a mixed REE sulfate solution at an equimolar initial concentration range of 0.1-1 mol/L of each REE ion.The highest adsorption capacities for the suspension are for Sm and Eu which are 57% and 46% higher,respectively,compared to the average REE adsorption capacity.The biofilms also preferentially adsorb Sm,Eu,Yb and Lu at 0.035,0.033,0.033,and 0.031 mmol/g,respectively.The impact of dissolved divalent ions of Ca,Mg,and Fe on REE adsorption was also assessed.When Ca and Mg are added in equimolar amounts to0.1-1 mmol/L solutions of equimolar La,Eu,and Yb sulfate,the amount of REEs adsorbed onto suspensions increases by 30% while when Fe is added,it decreases by 10%.No change is observed in biofilms except when Fe is added resulting in a reduction of the adsorption capacity by 40%.A possible explanation for the role of Fe is attributed to the formation of stronger bonds at the binding sites compared to Ca and Mg.展开更多
Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we repo...Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we report a new kind of bismuth oxybromide(BiOBr,BOB)with piezoelectric property regulated by oxygen vacancies(OVs).Compared with pure BOB,BOB with OVs(BOB-OV)could enhance photocatalytic CO_(2) reduction efficiency under the ultrasonic force,achieving durable CO_(2) reduction process to superior production rates of CO(54.4μmol g^(-1) h^(-1))with a high selectivity(92%).Moderate OVs concentration changed the degree of Bi-Br stretching in the BOB-OV to produce strong dipole moments,which endowed BOB-OV with strong spontaneous piezoelectric polarization ability under external force.Ultrasonic piezoelectric effects were innovatively integrated into the photocatalytic reaction,which not only provided an alternating force field to modulate the spontaneous polarization of BOB-OV,thereby maintaining efficient photogenerated charge separation,but also lowered the reaction energy barrier of CO_(2) by high stress,ultimately improving CO product selectivity.This study is the first to leverage OVs-induced piezoelectric polarization effects to enhance the performance and product selectivity of photocatalytic CO_(2) reduction,providing new directions and insights for defect engineering to contribute to photocatalysis.展开更多
Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has receive...Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has received much attention.In this work,Cu/Fe 2D bimetallic metal-organic frameworks were synthesized by a facile method applied as cathode materials without high-temperature carbonization.Bimetallic centers(Cu,Fe)with enhanced intrinsic activity demonstrated higher removal efficiency.Meanwhile,the 2D nanosheet reduced themass transfer barrier between the catalyst and nitrate and increased the reaction kinetics.Therefore,the catalysts with a 2D structure showed much better removal efficiency than other structures(3D MOFs and BulkMOFs).Under optimal conditions,Cu/Fe-2D MOF exhibited high nitrate removal efficiency(87.8%)and ammonium selectivity(89.3%)simultaneously.The ammonium yielded up to significantly 907.2μg/(hr·mg_(cat))(7793.8μg/(hr·mg_(metal)))with Faradaic efficiency of 62.8%at an initial 100 mg N/L.The catalyst was proved to have good stability and was recycled 15 times with excellent effect.DFT simulations confirm the reduced Gibbs free energy of Cu/Fe-2D MOF.This study demonstrates the promising application of Cu/Fe-2D MOF in nitrate reduction to ammonia and provides new insights for the design of efficient electrode materials.展开更多
Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;...Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity.展开更多
Solar energy-powered photocatalytic processes represent a promising avenue for sustainable energy and chemical production.Among these,lead-free halide perovskites(LFHPs)have garnered attention as a next-generation cla...Solar energy-powered photocatalytic processes represent a promising avenue for sustainable energy and chemical production.Among these,lead-free halide perovskites(LFHPs)have garnered attention as a next-generation class of photocatalysts for CO_(2) reduction,offering the advantages of high light absorption and low toxicity.However,the practical application of LFHPs remains constrained by limited catalytic activity and poor product selectivity.This review discusses the advancements in strategies to enhance the catalytic efficiency of LFHPs,such as compositional engineering,surface passivation,and heterostructure formation.These approaches aim to optimize charge carrier dynamics,reduce recombination rates,and improve stability under reaction conditions.Emphasis is also placed on methods to control product selectivity,including tailored reaction envi-ronments,co-catalyst integration,and fine-tuning electronic band structures.The discussion extends to key challenges such as material stability under photocatalytic conditions,scalability for industrial applications,and a deeper understanding of reaction mechanisms at the molecular level.Finally,future prospects highlight the critical role of LFHPs in achieving efficient,scalable,and eco-friendly solar-driven chemical synthesis,high-lighting their potential to reshape the landscape of sustainable photocatalysis.展开更多
In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-ti...In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-tion detected IR spectroscopy(NRIFD-IR)technique.The spectral range was from 2700 cm^(−1)to 7250 cm^(−1).Upon radiation with a 118 nm laser,signals corresponding to the cationic 2-EE(m/z=90)and dissociative ioniza-tion products(m/z=72,59,46,and 45)were detected.The action IR spectra,derived from the signal variations of 2-EE and its fragments upon IR radiation,display differences,suggest-ing vibrational mode selectivity in the dissociative ionization process.To complement the ex-perimental findings,we performed density functional theory calculations at the B3LYP-D3(BJ)/def2-TZVPP level to determine the structures and anharmonic IR spectra of neutral and cationic 2-EE.The computed spectra showed good agreement with the experimental re-sults.展开更多
The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))a...The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))and surface-loaded(xAu/TiO_(2))ways by MOF derivation strategy,reported a catalyst 0.5Au@TiO_(2)exhibited a CH_(3)OH yield of 32.5μmol·g^(-1)·h^(-1)and a CH_(3)OH selectivity of 80.6%under catalytic conditions of only CH_(4),O_(2),and H_(2)O.Mechanically speaking,the catalytic activity was controlled by both electron-hole separation efficiency and core-shell structure.The interfacial contact between Au nanoparticles and TiO_(2)in xAu@TiO_(2)and xAu/TiO_(2)induced the formation of oxygen vacancies,with 0.5 Au content showing the highest oxygen vacancy concentration.At the same Au content,xAu@TiO_(2)generated more oxygen vacancies than xAu/TiO_(2).The oxygen vacancy acted as an effective electron cold trap,which enhanced the photogenerated carrier separation efficiency and thereby improved the catalytic activity.In-situ DRIFTs revealed that the isolated OH(non-hydrogen bond adsorption)were key species for the methane selective oxidation,playing a role in the activation of CH_(4)to^(*)CH_(3).However,an overabundance of isolated OH led to severe overoxidation.Fortunately,the core-shell structure over xAu@TiO_(2)provided a slow-release environment for isolated OH through the intermediate state of^(*)OH(hydrogen bond adsorption)to balance the formation rate and consumption rate of isolated OH,doubling the methanol yield and increasing the>29%selectivity.These results showed a new strategy for the control of the overoxidation rate via a strategy of MOF encapsulation followed by pyrolytic derivation for methane selective oxidation.展开更多
In contrast to heterogeneous network frameworks(e.g.,covalent organic frameworks and metal‐organic frameworks)and porous organic polymers,porous organic cages(POCs)are soluble molecules in common organic solvents tha...In contrast to heterogeneous network frameworks(e.g.,covalent organic frameworks and metal‐organic frameworks)and porous organic polymers,porous organic cages(POCs)are soluble molecules in common organic solvents that provide significant potential for homogeneous catalysis.Herein,we report a triphenylphosphine‐derived quasi‐porous organic cage(denoted as POC‐DICP)as an efficient organic molecular cage ligand for Rh/PPh_(3) system‐catalyzed homogeneous hydroformylation reactions.POC‐DICP not only displays enhanced hydroformylation selectivity(aldehyde selectivity as high as 97%and a linear‐to‐branch ratio as high as 1.89)but can also be recovered and reused via a simple precipitation method in homogeneous reaction systems.We speculate that the reason for the high activity and good selectivity is the favorable geometry(cone angle=123.88°)and electronic effect(P site is relatively electron‐deficient)of POC‐DICP,which were also demonstrated by density functional theory calculations and X‐ray absorption fine‐structure characterization.展开更多
Trawl is a main fishing gear in Chinese fishery,capturing large fish and letting small ones at large.However,long-term use of trawl would result in changes of phenotypic traits of the fish stocks,such as smaller size-...Trawl is a main fishing gear in Chinese fishery,capturing large fish and letting small ones at large.However,long-term use of trawl would result in changes of phenotypic traits of the fish stocks,such as smaller size-at-age and earlier age-at-maturation.In this study,we simulated a fish population with size characteristics of trawl fishing and the population produces one generation of offspring and lives for one year,used trawl to exploit the simulated fish population,and captured individuals by body size.We evaluated the impact of the changes on selectivity parameters,such as selective range and the length at 50% retention.Under fishing pressure,we specified the selectivity parameters,and determined that smaller selection rates and greater length at 50% retention were associated with an increased tendency towards miniaturization.展开更多
Ion exchange membranes with high permselectivity (the character of separatingcations from anions or anions from cations) and high selectivity (the character of separatingcations or anions of different valencies) are i...Ion exchange membranes with high permselectivity (the character of separatingcations from anions or anions from cations) and high selectivity (the character of separatingcations or anions of different valencies) are important for electrodialysis process. The Donnanequilibrium theory, based on the equilibrium of ions and no electric field, can not exactly explainthe permselectivity of ion exchange membrane for ED process, since it is impossible to set up a ionexchange equilibrium between membrane and solution and to neglect the influence of electricaldriving force on ions during ED process. A novel model named 'anti-electric potential' isestablished to interpret the permselectivity of ion exchange membrane, according to thedetermination of electric potential between membranes and the variation of elements content insolutions and membranes. The results of experiment prove that the 'anti-electric potential' reallyexists within membranes. As for the selectivity, the results reveal that electric potential andhydration energy have great influence on the concentration and mobility of ions in membranes.展开更多
Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experi...Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differ- ences of attractability exist between any two different diets when every two natural diets or all five diets are provided simul- taneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.展开更多
The translation activity is a process of the interlinguistic transmission of information realized by the information encoding and decoding.Encoding and decoding,cognitive practices operated in objective contexts,are i...The translation activity is a process of the interlinguistic transmission of information realized by the information encoding and decoding.Encoding and decoding,cognitive practices operated in objective contexts,are inevitably of selectivity ascribing to the restriction of contextual reasons.The translator as the intermediary agent connects the original author(encoder)and the target readers(decoder),shouldering the dual duties of the decoder and the encoder,for which his subjectivity is irrevocably manipulated by the selectivity of encoding and decoding.展开更多
Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 a...Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 and CeO2 exhibit better activity and selectivity than pure Cu catalyst due to Cu-support(ZrO2 and CeO2)interaction.Combining the structural characterizations with in-situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS),Cu/CeO2 shows the higher methanol selectivity due to the formation of main carbonates intermediates,which are closely related with the oxygen vacancies over Cu/CeO2.In contrast,bicarbonate and carboxyl species are observed on Cu/ZrO2,which originates from the hydroxyl groups presented on catalyst surfaces.Difference in CO2 adsorption intermediates results in the distinct methanol selectivity over the two catalysts.展开更多
Objective To examine whether the selectivity of visual cortical neurons to stimulus spatial frequencies would be affected by aging in cats.Methods In vivo extracellular single-unit recording techniques were employed t...Objective To examine whether the selectivity of visual cortical neurons to stimulus spatial frequencies would be affected by aging in cats.Methods In vivo extracellular single-unit recording techniques were employed to record the tuning responses of V1 neurons to different stimulus spatial frequencies in old and young adult cats.Results Statistical analysis showed that the mean optimal spatial frequency of grating stimuli that evoked the maximal response of V1 neurons in old cats was significantly lower than that in young adult cats.Furthermore,the mean high cut-off spatial frequency of grating stimuli that evoked the half amplitude of the maximal response of V1 neurons in old cats was also significantly lower than that in young adult cats.Conclusion These results are consistent with those reported in the V1 of old monkeys,suggesting that the age-related decline in the selectivity of visual cortical cells to spatial frequency could be generalized to all mammalian species and might contribute to visual acuity reduction in senescent individuals.展开更多
文摘The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.
基金support from the Chinese Academy of Sciences and University of Science and Technology of China,National Key Research and Development Program of China(No.2021YFA1500402)National Natural Science Foundation of China(Nos.21571167,51502282 and 22075266)Fundamental Research Funds for the Central Universities(Nos.WK2060190053 and WK2060190100)。
文摘Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are highly susceptible to framework charge,which plays a significant role in selective adsorption.Currently,ionic porous frameworks can be divided into two types.One of them is composed of a charged backbone and counter ions.The framework with zwitterionic channels is another type.It is composed of regular and alternating arrangements of cationic and anionic building units.Herein,we report a hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}_nwith 1D channel exhibits unique adsorption selectivity for Ar against N_(2)and CO_(2).Density functional theory(DFT)results suggest that CO_(2)cannot be adsorbed by HIF at the experimental temperature due to a positive adsorption free energy.In addition,due to a relatively large diffusion barrier at 77 K,N_(2)molecules hardly diffuse in HIF channels,while Ar has a negligible diffusion barrier.The unique net positively-charged space in the channel is the key to the unusual phenomena,based on DFT simulations and structural analysis.The findings in this work proposes the new adsorption mechanism and provides unique perspective for special separation applications,such as isotope and noble gasses separations.
文摘BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with ASD display marked food selectivity,often restricting themselves to a narrow range of foods.The problems associated with feeding children with ASD can vary widely,from mild cases that pose no immediate health risks,to more severe situations with a risk of mal-nutrition or,conversely,overeating.This scoping review aims to provide an in-depth overview of the frequency,nature and factors related to food selectivity in children with autism.AIM To comprehensively review the literature on food selectivity in ASD.METHODS A systematic review of the literature was conducted using the PubMed,Web of Science and EBSCO databases,to identify articles published in English from 2014 until 2024.Studies on a sample diagnosed with ASD and food selectivity were included.The selected databases were chosen for their broad coverage of the scientific literature.These databases represent reliable sources of high-quality articles,ensuring a comprehensive and up-to-date search.RESULTS We evaluated 222 studies on food selectivity in autism,from which duplicates were removed and unrelated titles were filtered out.Finally,9 articles were included in the review.Five articles provide a general overview of the phenomenon,analysing its nature and factors.Two studies delve into sensory sensitivity,in particular the impact of food textures,tastes and smells.Finally,two studies focus on problem behaviour during mealtimes.CONCLUSION Children with ASD have greater food selectivity than the neurotypical population.The diet should contain a greater variety of fruit,vegetables,yoghurt,while reducing the consumption of rice and pasta.
基金the National Natural Science Foundation of China(Nos.22125604,22106100,21976117,22276119)Shanghai Rising-Star Program(No.22QA1403700).
文摘Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles.
文摘Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidation offers a more sustainable and milder alternative;however,it faces challenges such as aldehyde overoxidation and susceptibility to base-catalyzed Cannizzaro disproportionation.Electrochemical glycerol oxidation to glyceraldehyde is a representative example,which typically requires precious metal-based electrocatalysts but still suffers from low selectivity and activity.Here,we report a metal-free oxidation strategy mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl.By systematically investigating the redox thermodynamics and kinetics of TEMPO across a broad pH range,we construct a Pourbaix diagram and elucidate the relative kinetics of each reaction step.These insights allow us to explain the anomalously high apparent Faradaic efficiency(~200%)observed under acidic conditions,and identify neutral media as the optimal environment for selective glyceraldehyde production.Under optimized conditions,our system achieves a glyceraldehyde Faradaic efficiency exceeding 93%and a partial current density of 23.3 mA cm^(-2)at 0.57 V—more than doubling the performance of the best reported precious metal-based systems.Furthermore,the versatility of this strategy extends to the selective oxidation of other primary alcohols to their corresponding aldehydes with near-unity selectivity.
基金supported by National Nature Science Foundation of China(Nos.92161202 and 22121005)China Postdoctoral Science Foundation(Nos.2023M741814 and 2023M741815)+2 种基金Postdoctoral Fellowship Program of CPSF(No.GZC20231170)Natural Science Foundation of Science&Technology Department of Sichuan Province(No.2023NSFSC110)Research and Innovation Team of China West Normal University(No.KCXTD2023-1)。
文摘Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3).
基金supported by Natural Sciences and Engineering Research Council of Canada Strategic Grants program(463037-14)Discovery Grants program(2016-05524,2022-04881,2020-04262)。
文摘The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsorbing REEs onto microalgae,but biomass immobilization and light delivery challenges remain.It was recently shown that REEs biosorb 160% more on algal biofilms than suspended biomass due to the extracellular polymeric substance(EPS) matrix that grows abundantly in biofilms.In this work,we present findings on biosorption selectivity for different REEs in sulfate solutions.The maximum adsorption capacities of Euglena mutabilis suspensions and biofilms were determined for a mixed REE sulfate solution at an equimolar initial concentration range of 0.1-1 mol/L of each REE ion.The highest adsorption capacities for the suspension are for Sm and Eu which are 57% and 46% higher,respectively,compared to the average REE adsorption capacity.The biofilms also preferentially adsorb Sm,Eu,Yb and Lu at 0.035,0.033,0.033,and 0.031 mmol/g,respectively.The impact of dissolved divalent ions of Ca,Mg,and Fe on REE adsorption was also assessed.When Ca and Mg are added in equimolar amounts to0.1-1 mmol/L solutions of equimolar La,Eu,and Yb sulfate,the amount of REEs adsorbed onto suspensions increases by 30% while when Fe is added,it decreases by 10%.No change is observed in biofilms except when Fe is added resulting in a reduction of the adsorption capacity by 40%.A possible explanation for the role of Fe is attributed to the formation of stronger bonds at the binding sites compared to Ca and Mg.
文摘Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we report a new kind of bismuth oxybromide(BiOBr,BOB)with piezoelectric property regulated by oxygen vacancies(OVs).Compared with pure BOB,BOB with OVs(BOB-OV)could enhance photocatalytic CO_(2) reduction efficiency under the ultrasonic force,achieving durable CO_(2) reduction process to superior production rates of CO(54.4μmol g^(-1) h^(-1))with a high selectivity(92%).Moderate OVs concentration changed the degree of Bi-Br stretching in the BOB-OV to produce strong dipole moments,which endowed BOB-OV with strong spontaneous piezoelectric polarization ability under external force.Ultrasonic piezoelectric effects were innovatively integrated into the photocatalytic reaction,which not only provided an alternating force field to modulate the spontaneous polarization of BOB-OV,thereby maintaining efficient photogenerated charge separation,but also lowered the reaction energy barrier of CO_(2) by high stress,ultimately improving CO product selectivity.This study is the first to leverage OVs-induced piezoelectric polarization effects to enhance the performance and product selectivity of photocatalytic CO_(2) reduction,providing new directions and insights for defect engineering to contribute to photocatalysis.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52370044 and 21976134)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(Nos.PCRRK21003 and PCRRK21001)+1 种基金Shanghai Scientific Research Plan Project(No.23ZR1467000)the State Key Laboratory of Treatments and Recycling for Organic Effluents by Adsorption in Petroleum and Chemical Industry(No.SDHY2206).
文摘Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has received much attention.In this work,Cu/Fe 2D bimetallic metal-organic frameworks were synthesized by a facile method applied as cathode materials without high-temperature carbonization.Bimetallic centers(Cu,Fe)with enhanced intrinsic activity demonstrated higher removal efficiency.Meanwhile,the 2D nanosheet reduced themass transfer barrier between the catalyst and nitrate and increased the reaction kinetics.Therefore,the catalysts with a 2D structure showed much better removal efficiency than other structures(3D MOFs and BulkMOFs).Under optimal conditions,Cu/Fe-2D MOF exhibited high nitrate removal efficiency(87.8%)and ammonium selectivity(89.3%)simultaneously.The ammonium yielded up to significantly 907.2μg/(hr·mg_(cat))(7793.8μg/(hr·mg_(metal)))with Faradaic efficiency of 62.8%at an initial 100 mg N/L.The catalyst was proved to have good stability and was recycled 15 times with excellent effect.DFT simulations confirm the reduced Gibbs free energy of Cu/Fe-2D MOF.This study demonstrates the promising application of Cu/Fe-2D MOF in nitrate reduction to ammonia and provides new insights for the design of efficient electrode materials.
基金supported by the Youth Autonomous Innovation Funding from Army Engineering University of PLA(KYJBJKQTZQ23005)the Basic Discipline Incubation Funding from Army Engineering University of PLA(KYJBJKQTZK23011).
文摘Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity.
基金Prof.X.S.Tang acknowledges the financial support of the National Natural Science Foundation of China(62375032)the Natural Science Foundation of Chongqing(No.CSTB2023TIAD-KPX0017)+3 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)Dr.D.F.Wu acknowledges the financial support of the National Natural Science Foundation of China(22408362)the China National Postdoctoral Program for Innovative Talents(Certificate Number:BX20230355)the China Postdoctoral Science Foundation(Certificate Number:2024M753165).
文摘Solar energy-powered photocatalytic processes represent a promising avenue for sustainable energy and chemical production.Among these,lead-free halide perovskites(LFHPs)have garnered attention as a next-generation class of photocatalysts for CO_(2) reduction,offering the advantages of high light absorption and low toxicity.However,the practical application of LFHPs remains constrained by limited catalytic activity and poor product selectivity.This review discusses the advancements in strategies to enhance the catalytic efficiency of LFHPs,such as compositional engineering,surface passivation,and heterostructure formation.These approaches aim to optimize charge carrier dynamics,reduce recombination rates,and improve stability under reaction conditions.Emphasis is also placed on methods to control product selectivity,including tailored reaction envi-ronments,co-catalyst integration,and fine-tuning electronic band structures.The discussion extends to key challenges such as material stability under photocatalytic conditions,scalability for industrial applications,and a deeper understanding of reaction mechanisms at the molecular level.Finally,future prospects highlight the critical role of LFHPs in achieving efficient,scalable,and eco-friendly solar-driven chemical synthesis,high-lighting their potential to reshape the landscape of sustainable photocatalysis.
基金funded by the National Natural Science Foundation of China(No.22288201)the Chinese Academy of Sciences(GJJSTD20220001)the Innovation Program for Quantum Science and Technology(No.2021ZD0303305)。
文摘In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-tion detected IR spectroscopy(NRIFD-IR)technique.The spectral range was from 2700 cm^(−1)to 7250 cm^(−1).Upon radiation with a 118 nm laser,signals corresponding to the cationic 2-EE(m/z=90)and dissociative ioniza-tion products(m/z=72,59,46,and 45)were detected.The action IR spectra,derived from the signal variations of 2-EE and its fragments upon IR radiation,display differences,suggest-ing vibrational mode selectivity in the dissociative ionization process.To complement the ex-perimental findings,we performed density functional theory calculations at the B3LYP-D3(BJ)/def2-TZVPP level to determine the structures and anharmonic IR spectra of neutral and cationic 2-EE.The computed spectra showed good agreement with the experimental re-sults.
文摘The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))and surface-loaded(xAu/TiO_(2))ways by MOF derivation strategy,reported a catalyst 0.5Au@TiO_(2)exhibited a CH_(3)OH yield of 32.5μmol·g^(-1)·h^(-1)and a CH_(3)OH selectivity of 80.6%under catalytic conditions of only CH_(4),O_(2),and H_(2)O.Mechanically speaking,the catalytic activity was controlled by both electron-hole separation efficiency and core-shell structure.The interfacial contact between Au nanoparticles and TiO_(2)in xAu@TiO_(2)and xAu/TiO_(2)induced the formation of oxygen vacancies,with 0.5 Au content showing the highest oxygen vacancy concentration.At the same Au content,xAu@TiO_(2)generated more oxygen vacancies than xAu/TiO_(2).The oxygen vacancy acted as an effective electron cold trap,which enhanced the photogenerated carrier separation efficiency and thereby improved the catalytic activity.In-situ DRIFTs revealed that the isolated OH(non-hydrogen bond adsorption)were key species for the methane selective oxidation,playing a role in the activation of CH_(4)to^(*)CH_(3).However,an overabundance of isolated OH led to severe overoxidation.Fortunately,the core-shell structure over xAu@TiO_(2)provided a slow-release environment for isolated OH through the intermediate state of^(*)OH(hydrogen bond adsorption)to balance the formation rate and consumption rate of isolated OH,doubling the methanol yield and increasing the>29%selectivity.These results showed a new strategy for the control of the overoxidation rate via a strategy of MOF encapsulation followed by pyrolytic derivation for methane selective oxidation.
文摘In contrast to heterogeneous network frameworks(e.g.,covalent organic frameworks and metal‐organic frameworks)and porous organic polymers,porous organic cages(POCs)are soluble molecules in common organic solvents that provide significant potential for homogeneous catalysis.Herein,we report a triphenylphosphine‐derived quasi‐porous organic cage(denoted as POC‐DICP)as an efficient organic molecular cage ligand for Rh/PPh_(3) system‐catalyzed homogeneous hydroformylation reactions.POC‐DICP not only displays enhanced hydroformylation selectivity(aldehyde selectivity as high as 97%and a linear‐to‐branch ratio as high as 1.89)but can also be recovered and reused via a simple precipitation method in homogeneous reaction systems.We speculate that the reason for the high activity and good selectivity is the favorable geometry(cone angle=123.88°)and electronic effect(P site is relatively electron‐deficient)of POC‐DICP,which were also demonstrated by density functional theory calculations and X‐ray absorption fine‐structure characterization.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest of China(No.201203018)the National Key Technology Research and Development Program of China(No.2006BAD09A05)
文摘Trawl is a main fishing gear in Chinese fishery,capturing large fish and letting small ones at large.However,long-term use of trawl would result in changes of phenotypic traits of the fish stocks,such as smaller size-at-age and earlier age-at-maturation.In this study,we simulated a fish population with size characteristics of trawl fishing and the population produces one generation of offspring and lives for one year,used trawl to exploit the simulated fish population,and captured individuals by body size.We evaluated the impact of the changes on selectivity parameters,such as selective range and the length at 50% retention.Under fishing pressure,we specified the selectivity parameters,and determined that smaller selection rates and greater length at 50% retention were associated with an increased tendency towards miniaturization.
文摘Ion exchange membranes with high permselectivity (the character of separatingcations from anions or anions from cations) and high selectivity (the character of separatingcations or anions of different valencies) are important for electrodialysis process. The Donnanequilibrium theory, based on the equilibrium of ions and no electric field, can not exactly explainthe permselectivity of ion exchange membrane for ED process, since it is impossible to set up a ionexchange equilibrium between membrane and solution and to neglect the influence of electricaldriving force on ions during ED process. A novel model named 'anti-electric potential' isestablished to interpret the permselectivity of ion exchange membrane, according to thedetermination of electric potential between membranes and the variation of elements content insolutions and membranes. The results of experiment prove that the 'anti-electric potential' reallyexists within membranes. As for the selectivity, the results reveal that electric potential andhydration energy have great influence on the concentration and mobility of ions in membranes.
基金the Major State Basic Research of China(Grant No.G1999012011)the State Agriculture Program(Grant No.K2002-16) the Initializing Fund for Teachers of Ocean University of China.
文摘Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differ- ences of attractability exist between any two different diets when every two natural diets or all five diets are provided simul- taneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.
文摘The translation activity is a process of the interlinguistic transmission of information realized by the information encoding and decoding.Encoding and decoding,cognitive practices operated in objective contexts,are inevitably of selectivity ascribing to the restriction of contextual reasons.The translator as the intermediary agent connects the original author(encoder)and the target readers(decoder),shouldering the dual duties of the decoder and the encoder,for which his subjectivity is irrevocably manipulated by the selectivity of encoding and decoding.
基金financially supported by the National Natural Science Foundation of China (21577014, 21876019, 21825203, 21688102)Programme of Introducing Talents of Discipline to Universities (B13012)the fund of the State Key Laboratory of Catalysis in DICP (Y401010502)
文摘Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 and CeO2 exhibit better activity and selectivity than pure Cu catalyst due to Cu-support(ZrO2 and CeO2)interaction.Combining the structural characterizations with in-situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS),Cu/CeO2 shows the higher methanol selectivity due to the formation of main carbonates intermediates,which are closely related with the oxygen vacancies over Cu/CeO2.In contrast,bicarbonate and carboxyl species are observed on Cu/ZrO2,which originates from the hydroxyl groups presented on catalyst surfaces.Difference in CO2 adsorption intermediates results in the distinct methanol selectivity over the two catalysts.
基金supported by Natural Science Foundation of Anhui Province(No. 070413138)the Key Research Foundation of Education Department of Anhui Province,China(No. KJ2009A167)
文摘Objective To examine whether the selectivity of visual cortical neurons to stimulus spatial frequencies would be affected by aging in cats.Methods In vivo extracellular single-unit recording techniques were employed to record the tuning responses of V1 neurons to different stimulus spatial frequencies in old and young adult cats.Results Statistical analysis showed that the mean optimal spatial frequency of grating stimuli that evoked the maximal response of V1 neurons in old cats was significantly lower than that in young adult cats.Furthermore,the mean high cut-off spatial frequency of grating stimuli that evoked the half amplitude of the maximal response of V1 neurons in old cats was also significantly lower than that in young adult cats.Conclusion These results are consistent with those reported in the V1 of old monkeys,suggesting that the age-related decline in the selectivity of visual cortical cells to spatial frequency could be generalized to all mammalian species and might contribute to visual acuity reduction in senescent individuals.
