Objective: To identify the chemical constituents and biological activities of essential oil and crude methanol extract of Artemisia vulgaris(A.vulgaris) and Gaultheria fragrantissima(G.fragrantissima).Methods: Phytoch...Objective: To identify the chemical constituents and biological activities of essential oil and crude methanol extract of Artemisia vulgaris(A.vulgaris) and Gaultheria fragrantissima(G.fragrantissima).Methods: Phytochemical screening, total phenolic and flavonoid content, antibacterial activities, anti-oxidant assay of the crude extract were carried out to identify the biological activities and phytonutrients present in the extract.Furthermore, the chemical constituents present in the essential oil and crude methanol extract were analyzed using gas chromatography mass spectroscopy and high performance liquid chromatography(HPLC) analysis.Results: Gas chromatography mass spectroscopy analysis of essential oil from the aerial part of A.vulgaris revealed 24 different compounds in it.Sabinene(11.29%), b-thujone(19.19%), chrysanthenone(4.48%), camphor(11.89%), borneol(4.44%) and germacrene D(8.42%) were the major compounds.Similarly, leaves of G.fragrantissima contained methyl salicylate(95%) and asarone(4.64%).Furthermore, methanol extract of leaves of A.vulgaris and G.fragrantissima were found rich in the total flavonoids and phenolic content.HPLC analysis of the methanol extract of leaves A.vulgaris revealed the presence of morin and luteolin, whereas rutin was found as a major flavonoids compound in the leaves of G.fragrantissima.Further, methanol extract of the A.vulgaris and G.fragrantissima showed the highest antioxidant and antibacterial properties compared to the essential oil.Conclusions: The HPLC analysis of the methanol extract of A.vulgaris shows the presence of luteolin and morin, whereas G.fragrantissima reveals the presence of rutin and a glycosylated flavonoids.Results reveal that A.vulgaris oil is the rich source of monoterpene and sesquiterpene compounds.Furthermore, A.vulgaris and G.fragrantissima are the rich source of the phenolic and flavonoids compounds and show good antioxidant and antibacterial activity.展开更多
This paper presents a new technique,termed femtosecond laser shock peening ablation in liquids(fs-LSPAL),which can realize simultaneous crack micro/nanomanufacturing and hierarchical micro/nanolaser ablation,giving ri...This paper presents a new technique,termed femtosecond laser shock peening ablation in liquids(fs-LSPAL),which can realize simultaneous crack micro/nanomanufacturing and hierarchical micro/nanolaser ablation,giving rise to the formation of diverse multiscale hierarchical structures,such as macroporous ratcheted structures and enéchelon microfringes decorated with parabolic nanoripples.Through analysis of surface morphologies,many phenomena have been confirmed to take place during fs-LSPAL,including enéchelon cracks,nanostriation,ripple densification,crack branching,and selective formation of high spatial frequency laser-induced periodic surface structures of 100–200 nm in period.At a high laser power of 700 mW,fs-LSPAL at scanning speeds of 0.2 mm s^-1 and 1 mm s^-1 enables the generation of height-fluctuated and height-homogeneous hierarchical structures,respectively.The height-fluctuated structures can be used to induce‘colony’aggregates of embryonic EB3 stem cells.At 200 mW,fs-LSPAL at 1 mm s^-1 is capable of producing homogeneous tilt macroporous structures with cracked structures interleaved among them,which are the synergistic effects of bubble-induced light refraction/reflection ablation and cracks.As shown in this paper,the conventional laser ablation technique integrated with its self-driven unconventional cracking under extreme conditions expands the horizons of extreme manufacturing and offers more opportunities for complex surface structuring,which can potentially be used for biological applications.展开更多
The effect on the germination and seedling growth of radish(Raphanus sativus)seeds were examined employing a dielectric barrier discharge(DBD)at atmospheric pressure and room temperature for various treatment time.DBD...The effect on the germination and seedling growth of radish(Raphanus sativus)seeds were examined employing a dielectric barrier discharge(DBD)at atmospheric pressure and room temperature for various treatment time.DBD plasma using argon gas of flow rate 21 m^(-1)was employed in this study.Radish seeds were treated with DBD plasma for 1-5 min,respectively.Germination characteristics,seedling growth parameters,the contact angle of the seed coat,water uptake capacity,mass loss,the temperature of the seeds,chlorophyll,and carotenoid contents of the seedlings were measured before and after the DBD plasma treatments.Plasma treatment of radish seeds significantly increased germination-related characters,including germination percentage,fresh and dry weight,vigor index,and total carotenoids contents.However,the cumulative production rate was found to be decreased.Results from the experiment indicate an acceleration in the water uptake of the radish seeds and make the seed surface hydrophilic by plasma treatment.Scanning electron microscopy analysis showed that etching effects on the seed coat occurred after the argon plasma treatments,which affected the wettability of the radish seed.The experimental findings showed that seeds being treated by DBD plasma for 2 and 3 min had a positive effect on the germination and seedling growth of radish.展开更多
Nano gold （Au） particles loaded carbon nanotubes （Nano-Au/CNTs） were prepared by a new method. Polar groups and defects were introduced on the surface of the prepared Nano-Au/CNTs by a mixed acids treatment proces...Nano gold （Au） particles loaded carbon nanotubes （Nano-Au/CNTs） were prepared by a new method. Polar groups and defects were introduced on the surface of the prepared Nano-Au/CNTs by a mixed acids treatment process, and their electrocatalytic properties were investigated in this study. Comparing with the traditional preparation method, the particle nano size of Au can be controlled and it is easier to wash the sodium citrate by this method. Comparing t performance.展开更多
Ultrasound is used in various chemical reaction processes, and these reactions are influenced by ultrasonic frequency. A threshold power is required for the ultrasonic degradation reaction and oxidation reaction cause...Ultrasound is used in various chemical reaction processes, and these reactions are influenced by ultrasonic frequency. A threshold power is required for the ultrasonic degradation reaction and oxidation reaction caused by hydroxyl radicals, and the cavitation threshold power is also influenced by frequency generally. In this study, the effects of frequency on the threshold power of methylene blue degradation and KI oxidation were investigated in the range between 22.8 kHz and 1640 kHz. The threshold power of KI oxidation reaction increased with increasing frequency. This phenomenon well agrees with previous study, and it is revealed that the generation of I-3?ion is caused by oxidation reaction of Iˉ ions with hydroxyl radicals. On the other hand, the threshold power of methylene blue degradation reaction was not affected by frequency. The ultrasonic degradation of methylene blue is considered to be caused by hydroxyl radicals, and there is a linear relationship between degradation rate constant and sonochemical efficiency value. However, it is guessed that the degradation of methylene blue is occurred inside cavitation bubble by pyrolysis at high frequency regions.展开更多
Purpose: Telomere length (TL) is an indicator of age;however, hormonal influences complicate individual aging. It remains unclear whether TL shortening is a direct factor in both individual and cellular aging. Therefo...Purpose: Telomere length (TL) is an indicator of age;however, hormonal influences complicate individual aging. It remains unclear whether TL shortening is a direct factor in both individual and cellular aging. Therefore, we examined the direct relationship between TL and cellular senescence at the cellular level. Methods: Telomerase activity, TL, and gene expression were measured in cultured human lung-, fetal-, and skin-derived fibroblasts, human skin keratinocytes, and telomerase reverse transcriptase (TERT) gene-immortalized cells using detection kits, Cawthon’s method, and reverse transcription-quantitative polymerase chain reaction, respectively. Novel substances that elongate telomeres were screened to confirm cell rejuvenation effects. Results: Long-term cell culture of TIG-1-20 normal human fibroblasts resulted in TL shortening, decreased division rate, and senescence progression, whereas in OUMS-36T-2 cells, TL elongation via TERT gene transfer increased the division rate, reduced endoplasmic reticulum stress, and upregulated genes associated with young individuals, indicating that cellular rejuvenation occurs via TL elongation. In addition, a honey child powder (HCP) extract was found through screening, and the HCP extract strongly suppressed the menin gene, resulting in increased telomerase activity and extended cell lifespan. Upon addition of the HCP extract to skin fibroblasts, gene expression of moisturizing components, including collagen, hyaluronic acid, and elastin, increased, and exhibited a rejuvenating effect with an increase in elastin amount. Conclusions: TL elongation or shortening is involved in cell proliferation rate and cellular aging, and TL elongation rejuvenates cells. In addition, HCP extract has a rejuvenating effect on cells and is expected to be a rejuvenating compound.展开更多
Aggregation-induced emission luminogens(AIEgens)exhibit viscosity-responsive behavior resembling those of molecular rotors;however,their response mechanisms are more complex and cannot be adequately described using si...Aggregation-induced emission luminogens(AIEgens)exhibit viscosity-responsive behavior resembling those of molecular rotors;however,their response mechanisms are more complex and cannot be adequately described using simple rotational models.AIEgens demonstrate intricate dynamics that are highly dependent on their molecular structures.In this study,we synthesized water-soluble derivatives of representative AIEgens,including tetraphenylethene(TPE),bis(N,N-dialkylamino)anthracene(BDAA),and bridged stilbene,and systematically investigated the dependence of their photophysical properties in water/glycerol mixed solvents on temperature and viscosity.To elucidate the origin of their viscosity responsiveness,quantum chemical calculations were conducted to analyze their potential energy surfaces(PESs).The results revealed that compared to typical molecular rotors,these AIEgens exhibit significantly higher sensitivity to viscosity in low-viscosity regions.Notably,for TPE and BDAA derivatives,the viscosity responsiveness was found to be governed not by the activation energy barrier(ΔE_(a))based on the PES,but rather by the viscosity-dependent constraints on molecular structural changes.Furthermore,molecules possessing multiple aromatic rings or large,flexible,rotatable moieties were found to exhibit enhanced sensitivity to viscosity due to increased frictional interactions in solutions.This study provides critical insights into the mechanistic origins of the viscosity responsiveness of AIEgens,thereby advancing the fundamental understanding of their behavior and expanding their potential application as viscositysensitive probes.展开更多
This study delves into the pivotal role of sulfur vulcanization in defining the mechanical characteristics of natural rubber(NR)latex-dipped products.Utilizing sulfur vulcanization,known for its operational simplicity...This study delves into the pivotal role of sulfur vulcanization in defining the mechanical characteristics of natural rubber(NR)latex-dipped products.Utilizing sulfur vulcanization,known for its operational simplicity and cost-effectiveness,we examine its ability to enhance product elasticity and mechanical strength through various sulfidic bond formations such as mono-,di-,and polysulfidic bonds.Different vulcanization systems and sulfur contents were evaluated for their influence on the mechanical attributes of latex films,employing three types of NR latex,namely concentrated NR(CNR),deproteinized NR(DPNR),and small rubber particle NR(SRP),each representing distinct non-rubber components(NRCs).The study utilized advanced atomic force microscopy(AFM)equipped with PeakForce Quantitative Nanomechanical Mapping(QNM)to visualize and measure Young’s modulus distribution across the film of pre-vulcanized latex.Our findings reveal that films by CNR processed using the conventional vulcanization(CV)system exhibited enhanced tensile strength and elongation at break.It even showed a lower crosslink density than those processed using the efficient vulcanization(EV)system.Interestingly,DPNR films showed a more uniform distribution of Young’s modulus,correlating well with their superior mechanical strength.In contrast,SRP films showed excessive network structure formation in the particles due to accelerated vulcanization rates,hampering subsequent post-vulcanization interparticle crosslinking in film formation and remaining more rigid.The overall results Illustrate clearly that the ultimate mechanical properties of the latex films are strongly dependent on the type of sulfidic bonds formed.This research reveals further the very intricate relationship between the vulcanization methods,sulfur content,and latex type in optimizing the mechanical performance of NR latex products.It provides valuable insights for industry practices aimed at improving the quality and performance of latex-dipped goods.展开更多
Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic...Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.展开更多
The Nepal Himalayas is the source of many glacial and spring-fed river systems crisscrossing the mountainous terrain.There is an increasing recognition of small mountain rivers(SMRs)to have a significant combined expo...The Nepal Himalayas is the source of many glacial and spring-fed river systems crisscrossing the mountainous terrain.There is an increasing recognition of small mountain rivers(SMRs)to have a significant combined export of dissolved and particulate organic carbon to the global carbon flux.We analyzed fluvial sediments from two SMRs and compared the results with two large mountain rivers(LMRs)in Nepal.We investigated the organic matter(OM),its compositional variability,and seasonal export using a suite of lipid biomarkers,namely n-alkanes,n-alkanoic acids,n-alkanols,and sterols.The SMRs indicated a similarity in lipid distribution and were affected by a strong seasonal variability.The LMRs showed a distinct contrast in the distribution of lipids in suspended sediments.Bedload sediments in SMRs were derived from diverse sources with weak terrigenous dominance all-year-round compared to the suspended load.Functional lipids(n-alkanoic acids and n-alkanols)were the major constituents in SMR sediments,indicating better preservation.In contrast,n-alkane concentration dominated over other fractions in suspended sediments retrieved from LMRs.The biomarker trends differentiate SMRs from LMRs with lower transformed/degraded OM in SMRs.A common observation was the strong presence of even carbon compounds in short-chain n-alkanes in SMR bedload sediments and their predominance in suspended sediments in LMRs.Such an unusual trend is attributed to specific biomarker sources from the catchment and ongoing processes in fluvial systems.Topsoil colonized by fungal species under moist acidic conditions and autochthonous bacteria contributes to the organic matter pool in shallow SMRs.In LMRs,the contribution from thermally mature sedimentary hydrocarbons and the diagenetic reduction of nalkanoic acids to n-alkanes are additional contributors to the allochthonous carbon pool.The differences in lipid concentrations,their distribution,seasonality,and the size of rivers suggest differential preservation/degradation of the organic matter pool and their importance in contributing to the carbon budget.展开更多
In this study, large-scale production of microalgal lipid containing high levels of docosahexaenoic acid (DHA) by fermentation of Aurantiochytrium sp. KRS101 was performed. The microalgal strain yielded productivity o...In this study, large-scale production of microalgal lipid containing high levels of docosahexaenoic acid (DHA) by fermentation of Aurantiochytrium sp. KRS101 was performed. The microalgal strain yielded productivity of docosahex-aenoic acid (DHA) productivity of 1.08 and 1.6 g/L/d by fermentation at 300-L and 5000-L scale stirrer-type bioreactor. The productivity was significantly enhanced upto 5.6 g/L/d by fermentation at 6000-L scale airlift-type bioreactor, probably due to the reduced shearing force. The microalgal lipid could be efficiently recovered by safe extraction methods such as ethanol extraction, hot water extraction or supercritical fluid extraction, promising commercial potential of the microalgal DHA-rich lipid in the food and feed industry.展开更多
Downward transport of stratospheric air into the troposphere(identified as stratospheric intrusions)could potentially modify the radiation budget and chemical of the Earth's surface atmosphere.As the highest and l...Downward transport of stratospheric air into the troposphere(identified as stratospheric intrusions)could potentially modify the radiation budget and chemical of the Earth's surface atmosphere.As the highest and largest plateau on earth,the Tibetan Plateau including the Himalayas couples to global climate,and has attracted widespread attention due to rapid warming and cryospheric shrinking.Previous studies recognized strong stratospheric intrusions in the Himalayas but are poorly understood due to limited direct evidences and the complexity of the meteorological dynamics of the third pole.Cosmogenic^(35)S is a radioactive isotope predominately produced in the lower stratosphere and has been demonstrated as a sensitive chemical tracer to detect stratospherically sourced air mass in the planetary boundary layer.Here,we report 6-month(April–September 2018)observation of^(35)S in atmospheric sulfate aerosols(^(35)SO_(4)^(2-))collected from a remote site in the Himalayas to reveal the stratospheric intrusion phenomenon as well as its potential impacts in this region.Throughout the sampling campaign,the^(35)SO_(4)^(2-)concentrations show an average of 1,070±980 atoms/m^(3).In springtime,the average is 1,620±730 atoms/m^(3),significantly higher than the global existing data measured so far.The significant enrichments of^(35)SO_(4)^(2-)measured in this study verified the hypothesis that the Himalayas is a global hot spot of stratospheric intrusions,especially during the springtime as a consequence of its unique geology and atmospheric couplings.In combined with the ancillary evidences,e.g.,oxygen-17 anomaly in sulfate and modeling results,we found that the stratospheric intrusions have a profound impact on the surface ozone concentrations over the study region,and potentially have the ability to constrain how the mechanisms of sulfate oxidation are affected by a change in plateau atmospheric properties and conditions.This study provides new observational constraints on stratospheric intrusions in the Himalayas,which would further provide additional information for a deeper understanding on the environment and climatic changes over the Tibetan Plateau.展开更多
Dry Matter (DM) is a powdery substance which is composed of micro droplets and surrounding hydrophobic silica nanoparticles. Because of the much larger surface area than that of the corresponding bulk liquid, DM, whic...Dry Matter (DM) is a powdery substance which is composed of micro droplets and surrounding hydrophobic silica nanoparticles. Because of the much larger surface area than that of the corresponding bulk liquid, DM, which contains amino-functionalized ionic liquids (ILs), is a promising CO2 absorption material provided with quick absorption speed. In the present study, we successfully prepared powdery DMs by utilizing aqueous solutions of amino acid-based ILs (tetraethylammonium glycine [N2222][Gly], and tetraethylammonium alanine [N2222][Ala]). Although a DM with lysine-based IL (N2222) [Lys]) was also prepared, only a soufflé-like material was obtained. We measured CO2 absorption performance for the DMs to find that the mass-base absorption ability (mass-base A.A.) (CO2 mol/DM kg) and the mol-base one (CO2 mol/IL mol) of [N2222][Lys] were ca. two times of [N2222][Gly] and [N2222][Ala], while the absorption speed of the former was inferior to the latter two, i.e., ca.15 min vs. 5 min for 90% absorption. In order to improve the mass-base A.A. of [N2222][Gly], we used 10% of aqueous poly(allylamine) (PAlAm) solution instead of water. The resultant mass-base A.A. proved to be significantly larger (1.9) than either of those of the respective single component systems (1.1 and 0.75 for the bulk IL and aq. PAlAm, respectively), and comparable to the A.A. (1.6 - 2.5) of 20% - 30% monoethanolamine solution which is commonly used in industrial application.展开更多
A laser trapping-microspectroscopy technique combined with excitation energy transfer from a fluorescent cationic dye (Rhodamine B, RB+) to a non-fluorescent cationic dye (Malachite Green, MG+) was employed to study p...A laser trapping-microspectroscopy technique combined with excitation energy transfer from a fluorescent cationic dye (Rhodamine B, RB+) to a non-fluorescent cationic dye (Malachite Green, MG+) was employed to study pH effects on the diffusion coefficients of MG+ (D(MG+)) in single cation-exchange resin microparticles with the diameters of 16 μm. When RB+-pre-adsorbed resin particles were soaked in an aqueous MG+ solution, the RB+ fluorescence was quenched gradually with the soaking time. The time course of the quenching efficiency of RB+ by MG+ was then used to evaluate the D(MG+) value in the particle. The D(MG+) value increased from 1.1 × 10-11 to 4.3 × 10-11 cm2.s–1 on going the solu- tion pH value from 9 to 4. The results were explained reasonably by a Donnan electric potential model.展开更多
Aggregation-induced emission luminogens(AIEgens)are typically largeπ-conjugated molecules,but their low affinity and noninvasiveness toward analytes limit practical applications.To address this,smaller,more planar AI...Aggregation-induced emission luminogens(AIEgens)are typically largeπ-conjugated molecules,but their low affinity and noninvasiveness toward analytes limit practical applications.To address this,smaller,more planar AIEgens are needed.Stilbene,though structurally suitable,lacks visible luminescence.Here,we report a minimally modified stilbene-based AIEgen-4-dipropylamino-4'-cyano-bridged stilbene(DpCBS[7])-that exhibits fluorescence solvatochromism and efficient AIE across a broad polarity range in the visible region.DpCBS[7]exhibits low quantum yields(Φ_(fl)=0.010.04)in solvents from nonpolar n-hexane to polar dimethyl sulfoxide,with large Stokes shifts,viscosity-sensitive luminescence,and highly efficient solid-state luminescence(Φ_(fl)=0.70).To elucidate its dual solvatochromic and AiE behavior,femtosecond transient absorption spectroscopy was conducted.In solution,DpCBS[7]displays transient absorption with lifetimes of 21 ps(toluene)and 56 ps(acetonitrile)at 293 K,indicating ultrafast nonradiative decay leading to low Φ_(fl).Arrhenius analysis over the temperature range of 263-313 K revealed activation energies(ΔE_(a))of 9.90kJ/mol in toluene and 12.8 kJ/mol in acetonitrile for the S_(1)→S_(0) decay of DpCBS[7].The ΔE_(a) values show no clear systematic dependence on solvent polarity.In contrast,pre-exponential factor A remains consistently high regardless of solvent polarity,indicating that the striking photophysical response is governed primarily by the pre-exponential factor rather than by modulation of the activation energy.These findings highlight the fundamental importance of tailoring the distribution function through structural modification as a robust strategy to control AiE characteristics.展开更多
Circularly polarized luminescence(CPL)has attracted considerable attention owing to its wide range of potential applications.Cholesteric liquid crystals(CLCs)are promising candidates for CPL-active materials because o...Circularly polarized luminescence(CPL)has attracted considerable attention owing to its wide range of potential applications.Cholesteric liquid crystals(CLCs)are promising candidates for CPL-active materials because of their ease of fabrication,stimulus responsiveness,and ability to achieve high dissymmetry factors(|g_(lum)|).In most studies on CPL-active CLCs,non-mesogenic luminophores are doped into commercially available liquid crystals(LCs).However,their low solubility in LCs(typically only a few wt%)and their tendency to disrupt LC alignment present challenges in achieving high|glum|values-particularly in thin cells-and in broadening the CPL spectra.Here,we report a new LC mixture comprising our previously designed mesogenic fluorophore and a commercially available LC.This strategy enables a markedly increased luminophore loading(up to∼50 wt%)and enhances the birefringence of the LC matrix.As a result,we achieved a notably high|glum|value of 1.25 even in thin cells(2μm),together with significantly broadened CPL spectra.Furthermore,the emission wavelength was successfully tuned via Förster resonance energy transfer.This work demonstrates a rational design strategy for LC mixtures that yield CPL materials with high|g_(lum)|,advances the fundamental understanding of CPL generation in photoluminescent CLCs,and highlights their potential for future photonic and optoelectronic applications.展开更多
Arsenic(As)speciation for the phytoremediation by the Chinese brake fern was studied.In particular,the mechanism of how plants induce compounds containing thiol(SH)and proteins by As exposure in terms of the relations...Arsenic(As)speciation for the phytoremediation by the Chinese brake fern was studied.In particular,the mechanism of how plants induce compounds containing thiol(SH)and proteins by As exposure in terms of the relationship between As and phosphate uptaken into plant cells was examined.Pteris vittata callus could effciently reduce As(V)to As(III)by the rapid introduction of reductase and synthesize thiols leading to phytochelatins production.Furthermore,Pteris vittata could control phosphate concentration in t...展开更多
Two-dimensional graphene and its derivatives exhibiting distinct physiochemical properties are intriguing building blocks for researchers from a large variety of scientific fields.Assembling graphene-based materials i...Two-dimensional graphene and its derivatives exhibiting distinct physiochemical properties are intriguing building blocks for researchers from a large variety of scientific fields.Assembling graphene-based materials into membrane layers brings great potentials for high-efficiency membrane processes.Particularly,pervaporation by graphene-based membranes has been intensively studied with respect to the membrane design and preparation.This review aims to provide an overview on the graphene-based membranes for pervaporation processes ranged from fabrication to application.Physical or chemical decoration of graphene-based materials is elaborated regarding their effects on the microstructure and performance.The mass transport of pervaporation through graphene-based membranes is introduced,and relevant mechanisms are described.Furthermore,performances of state-of-the-art graphene-based membranes for different pervaporation applications are summarized.Finally,the perspectives of current challenges and future directions are presented.展开更多
Background:Murraya koenigii(L.)Spreng.(Rutaceae)is an evergreen shrub distributed over the sub-tropical to lower temperate climatic zone of Nepal which has been used as spice in culinary practice and traditionally bei...Background:Murraya koenigii(L.)Spreng.(Rutaceae)is an evergreen shrub distributed over the sub-tropical to lower temperate climatic zone of Nepal which has been used as spice in culinary practice and traditionally being used to treat bites of poisonous animals,dysentery,skin diseases,vomiting,diarrhea,and inflammations.Objective:The main objective of this study is to study the enzyme inhibition potential of different extracts of M.koenigii leaves collected from western Nepal.Methods:Total flavonoid content,total phenolic content,in vitro antioxidant,𝛼α-amylase,lipase,elastase,tyrosinase,and cholinesterase inhibition activities analysis of M.koenigii in ethyl acetate,methanol,and water extract were evaluated.In addition,high-resolution mass spectrometry-based profiling of flavonoid molecules and their docking analysis were performed.Results:Results revealed the noteworthy radical scavenging activity of ethyl acetate extract against ABTS and DPPH.Among the analyzed enzymes,M.koenigii extracts revealed the highest inhibitory potential towards acetylcholinesterase(AChE)and butyrylcholinesterase(BChE)and only water extract showed the inhibition of tyrosinase.The HPLC-ESI-QTOF-MS analysis revealed the presence of Rutin,Quercetin,Ferulic acid,Hyperoside,Kaempferol-7-O-glucoside,and Morin in M.koenigii.Further,in silico docking analysis revealed the significant binding energy of these flavonoid molecules;especially Rutin with BChE.Conclusion:The ethyl acetate and methanolic extracts of M.koenigii showed paramount flavonoid and phenolic content along with noteworthy potential towardsthe inhibition of neuro-degradative enzymes such as BChE which can be characterized further for pharmacological applications.Further study on the isolation of metabolites and their pharmacological properties from M.koenigii is recommended.展开更多
Our previous research showed that aliphatic amines were put in order of high reactivity as “ethylamine > ammonia > t-butylamine > diethylamine” on the aromatic nucleophilic substitution of 1-dimetylamino-2,...Our previous research showed that aliphatic amines were put in order of high reactivity as “ethylamine > ammonia > t-butylamine > diethylamine” on the aromatic nucleophilic substitution of 1-dimetylamino-2,4-bis(trifluoroacetyl)-naphthalene 1 in acetonitrile. The DFT calculation study (B3LYP/6-31G* with solvation model) for the reactions of 1 with above four amines rationally explained the difference of each amines reactivity based on the energies of their Meisenheimer complexes 3 which are assumed to formed as the reaction intermediates in the course of the reaction giving the corresponding N-N exchange products 2. Intramolecular hydrogen bond between amino proton in 1-amino group and carbonyl oxygen in 2-trifluoroacetyl group stabilizes Meisenheimer complexes 3 effectively, and accelerates the substitution reaction from 1 to 2. Our calculation results also predicted that the above order of amines is also true if less polar toluene is used as a solvent instead of acetonitrile even though more enhanced conditions are required.展开更多
基金supported by Academy Partnership Program Track 1-1 funded by KOICA(APP-Track 1-1 2015-0249)
文摘Objective: To identify the chemical constituents and biological activities of essential oil and crude methanol extract of Artemisia vulgaris(A.vulgaris) and Gaultheria fragrantissima(G.fragrantissima).Methods: Phytochemical screening, total phenolic and flavonoid content, antibacterial activities, anti-oxidant assay of the crude extract were carried out to identify the biological activities and phytonutrients present in the extract.Furthermore, the chemical constituents present in the essential oil and crude methanol extract were analyzed using gas chromatography mass spectroscopy and high performance liquid chromatography(HPLC) analysis.Results: Gas chromatography mass spectroscopy analysis of essential oil from the aerial part of A.vulgaris revealed 24 different compounds in it.Sabinene(11.29%), b-thujone(19.19%), chrysanthenone(4.48%), camphor(11.89%), borneol(4.44%) and germacrene D(8.42%) were the major compounds.Similarly, leaves of G.fragrantissima contained methyl salicylate(95%) and asarone(4.64%).Furthermore, methanol extract of leaves of A.vulgaris and G.fragrantissima were found rich in the total flavonoids and phenolic content.HPLC analysis of the methanol extract of leaves A.vulgaris revealed the presence of morin and luteolin, whereas rutin was found as a major flavonoids compound in the leaves of G.fragrantissima.Further, methanol extract of the A.vulgaris and G.fragrantissima showed the highest antioxidant and antibacterial properties compared to the essential oil.Conclusions: The HPLC analysis of the methanol extract of A.vulgaris shows the presence of luteolin and morin, whereas G.fragrantissima reveals the presence of rutin and a glycosylated flavonoids.Results reveal that A.vulgaris oil is the rich source of monoterpene and sesquiterpene compounds.Furthermore, A.vulgaris and G.fragrantissima are the rich source of the phenolic and flavonoids compounds and show good antioxidant and antibacterial activity.
基金the financial support by RIKEN FY2019‘Emerging Collaboration Seed’of‘Collaboration Seed Fund’(Grant No.100948-201901010000-340130)。
文摘This paper presents a new technique,termed femtosecond laser shock peening ablation in liquids(fs-LSPAL),which can realize simultaneous crack micro/nanomanufacturing and hierarchical micro/nanolaser ablation,giving rise to the formation of diverse multiscale hierarchical structures,such as macroporous ratcheted structures and enéchelon microfringes decorated with parabolic nanoripples.Through analysis of surface morphologies,many phenomena have been confirmed to take place during fs-LSPAL,including enéchelon cracks,nanostriation,ripple densification,crack branching,and selective formation of high spatial frequency laser-induced periodic surface structures of 100–200 nm in period.At a high laser power of 700 mW,fs-LSPAL at scanning speeds of 0.2 mm s^-1 and 1 mm s^-1 enables the generation of height-fluctuated and height-homogeneous hierarchical structures,respectively.The height-fluctuated structures can be used to induce‘colony’aggregates of embryonic EB3 stem cells.At 200 mW,fs-LSPAL at 1 mm s^-1 is capable of producing homogeneous tilt macroporous structures with cracked structures interleaved among them,which are the synergistic effects of bubble-induced light refraction/reflection ablation and cracks.As shown in this paper,the conventional laser ablation technique integrated with its self-driven unconventional cracking under extreme conditions expands the horizons of extreme manufacturing and offers more opportunities for complex surface structuring,which can potentially be used for biological applications.
基金Nepal Academy of Science and Technology(NAST),Khumaltar,Lalitpur,Nepal for providing financial and technical support。
文摘The effect on the germination and seedling growth of radish(Raphanus sativus)seeds were examined employing a dielectric barrier discharge(DBD)at atmospheric pressure and room temperature for various treatment time.DBD plasma using argon gas of flow rate 21 m^(-1)was employed in this study.Radish seeds were treated with DBD plasma for 1-5 min,respectively.Germination characteristics,seedling growth parameters,the contact angle of the seed coat,water uptake capacity,mass loss,the temperature of the seeds,chlorophyll,and carotenoid contents of the seedlings were measured before and after the DBD plasma treatments.Plasma treatment of radish seeds significantly increased germination-related characters,including germination percentage,fresh and dry weight,vigor index,and total carotenoids contents.However,the cumulative production rate was found to be decreased.Results from the experiment indicate an acceleration in the water uptake of the radish seeds and make the seed surface hydrophilic by plasma treatment.Scanning electron microscopy analysis showed that etching effects on the seed coat occurred after the argon plasma treatments,which affected the wettability of the radish seed.The experimental findings showed that seeds being treated by DBD plasma for 2 and 3 min had a positive effect on the germination and seedling growth of radish.
基金supported by the China Postdoctoral Science Foundation (No. 2017M620048)
文摘Nano gold （Au） particles loaded carbon nanotubes （Nano-Au/CNTs） were prepared by a new method. Polar groups and defects were introduced on the surface of the prepared Nano-Au/CNTs by a mixed acids treatment process, and their electrocatalytic properties were investigated in this study. Comparing with the traditional preparation method, the particle nano size of Au can be controlled and it is easier to wash the sodium citrate by this method. Comparing t performance.
文摘Ultrasound is used in various chemical reaction processes, and these reactions are influenced by ultrasonic frequency. A threshold power is required for the ultrasonic degradation reaction and oxidation reaction caused by hydroxyl radicals, and the cavitation threshold power is also influenced by frequency generally. In this study, the effects of frequency on the threshold power of methylene blue degradation and KI oxidation were investigated in the range between 22.8 kHz and 1640 kHz. The threshold power of KI oxidation reaction increased with increasing frequency. This phenomenon well agrees with previous study, and it is revealed that the generation of I-3?ion is caused by oxidation reaction of Iˉ ions with hydroxyl radicals. On the other hand, the threshold power of methylene blue degradation reaction was not affected by frequency. The ultrasonic degradation of methylene blue is considered to be caused by hydroxyl radicals, and there is a linear relationship between degradation rate constant and sonochemical efficiency value. However, it is guessed that the degradation of methylene blue is occurred inside cavitation bubble by pyrolysis at high frequency regions.
文摘Purpose: Telomere length (TL) is an indicator of age;however, hormonal influences complicate individual aging. It remains unclear whether TL shortening is a direct factor in both individual and cellular aging. Therefore, we examined the direct relationship between TL and cellular senescence at the cellular level. Methods: Telomerase activity, TL, and gene expression were measured in cultured human lung-, fetal-, and skin-derived fibroblasts, human skin keratinocytes, and telomerase reverse transcriptase (TERT) gene-immortalized cells using detection kits, Cawthon’s method, and reverse transcription-quantitative polymerase chain reaction, respectively. Novel substances that elongate telomeres were screened to confirm cell rejuvenation effects. Results: Long-term cell culture of TIG-1-20 normal human fibroblasts resulted in TL shortening, decreased division rate, and senescence progression, whereas in OUMS-36T-2 cells, TL elongation via TERT gene transfer increased the division rate, reduced endoplasmic reticulum stress, and upregulated genes associated with young individuals, indicating that cellular rejuvenation occurs via TL elongation. In addition, a honey child powder (HCP) extract was found through screening, and the HCP extract strongly suppressed the menin gene, resulting in increased telomerase activity and extended cell lifespan. Upon addition of the HCP extract to skin fibroblasts, gene expression of moisturizing components, including collagen, hyaluronic acid, and elastin, increased, and exhibited a rejuvenating effect with an increase in elastin amount. Conclusions: TL elongation or shortening is involved in cell proliferation rate and cellular aging, and TL elongation rejuvenates cells. In addition, HCP extract has a rejuvenating effect on cells and is expected to be a rejuvenating compound.
基金JSPS Research Fellowships for Young Scientistssupported in part by JST SPRING,Japan(Nos.JPMJSP2106 and JPMJSP2180,Takuya Tanaka.and Yuki Sawatari.)+1 种基金MEXT/JSPS KAKENHI grants(No.23H02036,Gen-ichi Konishi)Murata Science and Education Foundation(Gen-ichi Konishi)。
文摘Aggregation-induced emission luminogens(AIEgens)exhibit viscosity-responsive behavior resembling those of molecular rotors;however,their response mechanisms are more complex and cannot be adequately described using simple rotational models.AIEgens demonstrate intricate dynamics that are highly dependent on their molecular structures.In this study,we synthesized water-soluble derivatives of representative AIEgens,including tetraphenylethene(TPE),bis(N,N-dialkylamino)anthracene(BDAA),and bridged stilbene,and systematically investigated the dependence of their photophysical properties in water/glycerol mixed solvents on temperature and viscosity.To elucidate the origin of their viscosity responsiveness,quantum chemical calculations were conducted to analyze their potential energy surfaces(PESs).The results revealed that compared to typical molecular rotors,these AIEgens exhibit significantly higher sensitivity to viscosity in low-viscosity regions.Notably,for TPE and BDAA derivatives,the viscosity responsiveness was found to be governed not by the activation energy barrier(ΔE_(a))based on the PES,but rather by the viscosity-dependent constraints on molecular structural changes.Furthermore,molecules possessing multiple aromatic rings or large,flexible,rotatable moieties were found to exhibit enhanced sensitivity to viscosity due to increased frictional interactions in solutions.This study provides critical insights into the mechanistic origins of the viscosity responsiveness of AIEgens,thereby advancing the fundamental understanding of their behavior and expanding their potential application as viscositysensitive probes.
基金supported by Mahidol University(Fundamental Fund:fiscal year 2024 by the National Science Research and Innovation Fund(NSRF),FF-078/2567)Academy of Tropical Agricultural Sciences for Science and Technology Innovation Team of National Tropical Agricultural Science Center(No.CATASCXTD202401)the National Research Council of Thailand(NRCT)via the Royal Golden Jubilee Ph.D.Program(No.PHD/0150/2560)。
文摘This study delves into the pivotal role of sulfur vulcanization in defining the mechanical characteristics of natural rubber(NR)latex-dipped products.Utilizing sulfur vulcanization,known for its operational simplicity and cost-effectiveness,we examine its ability to enhance product elasticity and mechanical strength through various sulfidic bond formations such as mono-,di-,and polysulfidic bonds.Different vulcanization systems and sulfur contents were evaluated for their influence on the mechanical attributes of latex films,employing three types of NR latex,namely concentrated NR(CNR),deproteinized NR(DPNR),and small rubber particle NR(SRP),each representing distinct non-rubber components(NRCs).The study utilized advanced atomic force microscopy(AFM)equipped with PeakForce Quantitative Nanomechanical Mapping(QNM)to visualize and measure Young’s modulus distribution across the film of pre-vulcanized latex.Our findings reveal that films by CNR processed using the conventional vulcanization(CV)system exhibited enhanced tensile strength and elongation at break.It even showed a lower crosslink density than those processed using the efficient vulcanization(EV)system.Interestingly,DPNR films showed a more uniform distribution of Young’s modulus,correlating well with their superior mechanical strength.In contrast,SRP films showed excessive network structure formation in the particles due to accelerated vulcanization rates,hampering subsequent post-vulcanization interparticle crosslinking in film formation and remaining more rigid.The overall results Illustrate clearly that the ultimate mechanical properties of the latex films are strongly dependent on the type of sulfidic bonds formed.This research reveals further the very intricate relationship between the vulcanization methods,sulfur content,and latex type in optimizing the mechanical performance of NR latex products.It provides valuable insights for industry practices aimed at improving the quality and performance of latex-dipped goods.
基金Supported by the National Natural Science Foundation of China（20776161）
文摘Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.
基金This work was supported by the funding provided by Ventenskapsådet(Grant No.2016-05642)to JR.
文摘The Nepal Himalayas is the source of many glacial and spring-fed river systems crisscrossing the mountainous terrain.There is an increasing recognition of small mountain rivers(SMRs)to have a significant combined export of dissolved and particulate organic carbon to the global carbon flux.We analyzed fluvial sediments from two SMRs and compared the results with two large mountain rivers(LMRs)in Nepal.We investigated the organic matter(OM),its compositional variability,and seasonal export using a suite of lipid biomarkers,namely n-alkanes,n-alkanoic acids,n-alkanols,and sterols.The SMRs indicated a similarity in lipid distribution and were affected by a strong seasonal variability.The LMRs showed a distinct contrast in the distribution of lipids in suspended sediments.Bedload sediments in SMRs were derived from diverse sources with weak terrigenous dominance all-year-round compared to the suspended load.Functional lipids(n-alkanoic acids and n-alkanols)were the major constituents in SMR sediments,indicating better preservation.In contrast,n-alkane concentration dominated over other fractions in suspended sediments retrieved from LMRs.The biomarker trends differentiate SMRs from LMRs with lower transformed/degraded OM in SMRs.A common observation was the strong presence of even carbon compounds in short-chain n-alkanes in SMR bedload sediments and their predominance in suspended sediments in LMRs.Such an unusual trend is attributed to specific biomarker sources from the catchment and ongoing processes in fluvial systems.Topsoil colonized by fungal species under moist acidic conditions and autochthonous bacteria contributes to the organic matter pool in shallow SMRs.In LMRs,the contribution from thermally mature sedimentary hydrocarbons and the diagenetic reduction of nalkanoic acids to n-alkanes are additional contributors to the allochthonous carbon pool.The differences in lipid concentrations,their distribution,seasonality,and the size of rivers suggest differential preservation/degradation of the organic matter pool and their importance in contributing to the carbon budget.
文摘In this study, large-scale production of microalgal lipid containing high levels of docosahexaenoic acid (DHA) by fermentation of Aurantiochytrium sp. KRS101 was performed. The microalgal strain yielded productivity of docosahex-aenoic acid (DHA) productivity of 1.08 and 1.6 g/L/d by fermentation at 300-L and 5000-L scale stirrer-type bioreactor. The productivity was significantly enhanced upto 5.6 g/L/d by fermentation at 6000-L scale airlift-type bioreactor, probably due to the reduced shearing force. The microalgal lipid could be efficiently recovered by safe extraction methods such as ethanol extraction, hot water extraction or supercritical fluid extraction, promising commercial potential of the microalgal DHA-rich lipid in the food and feed industry.
基金financially supported by the second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0605)the National Natural Science Foundation of China(42371151)+3 种基金the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2023)the research grant of State Key Laboratory of Isotope Geochemistry(SKLaBIG-KF-22-05)the Natural Science Foundation of Gansu Province(23JRRA648)China Postdoctoral Science Foundation(2022M723358)。
文摘Downward transport of stratospheric air into the troposphere(identified as stratospheric intrusions)could potentially modify the radiation budget and chemical of the Earth's surface atmosphere.As the highest and largest plateau on earth,the Tibetan Plateau including the Himalayas couples to global climate,and has attracted widespread attention due to rapid warming and cryospheric shrinking.Previous studies recognized strong stratospheric intrusions in the Himalayas but are poorly understood due to limited direct evidences and the complexity of the meteorological dynamics of the third pole.Cosmogenic^(35)S is a radioactive isotope predominately produced in the lower stratosphere and has been demonstrated as a sensitive chemical tracer to detect stratospherically sourced air mass in the planetary boundary layer.Here,we report 6-month(April–September 2018)observation of^(35)S in atmospheric sulfate aerosols(^(35)SO_(4)^(2-))collected from a remote site in the Himalayas to reveal the stratospheric intrusion phenomenon as well as its potential impacts in this region.Throughout the sampling campaign,the^(35)SO_(4)^(2-)concentrations show an average of 1,070±980 atoms/m^(3).In springtime,the average is 1,620±730 atoms/m^(3),significantly higher than the global existing data measured so far.The significant enrichments of^(35)SO_(4)^(2-)measured in this study verified the hypothesis that the Himalayas is a global hot spot of stratospheric intrusions,especially during the springtime as a consequence of its unique geology and atmospheric couplings.In combined with the ancillary evidences,e.g.,oxygen-17 anomaly in sulfate and modeling results,we found that the stratospheric intrusions have a profound impact on the surface ozone concentrations over the study region,and potentially have the ability to constrain how the mechanisms of sulfate oxidation are affected by a change in plateau atmospheric properties and conditions.This study provides new observational constraints on stratospheric intrusions in the Himalayas,which would further provide additional information for a deeper understanding on the environment and climatic changes over the Tibetan Plateau.
文摘Dry Matter (DM) is a powdery substance which is composed of micro droplets and surrounding hydrophobic silica nanoparticles. Because of the much larger surface area than that of the corresponding bulk liquid, DM, which contains amino-functionalized ionic liquids (ILs), is a promising CO2 absorption material provided with quick absorption speed. In the present study, we successfully prepared powdery DMs by utilizing aqueous solutions of amino acid-based ILs (tetraethylammonium glycine [N2222][Gly], and tetraethylammonium alanine [N2222][Ala]). Although a DM with lysine-based IL (N2222) [Lys]) was also prepared, only a soufflé-like material was obtained. We measured CO2 absorption performance for the DMs to find that the mass-base absorption ability (mass-base A.A.) (CO2 mol/DM kg) and the mol-base one (CO2 mol/IL mol) of [N2222][Lys] were ca. two times of [N2222][Gly] and [N2222][Ala], while the absorption speed of the former was inferior to the latter two, i.e., ca.15 min vs. 5 min for 90% absorption. In order to improve the mass-base A.A. of [N2222][Gly], we used 10% of aqueous poly(allylamine) (PAlAm) solution instead of water. The resultant mass-base A.A. proved to be significantly larger (1.9) than either of those of the respective single component systems (1.1 and 0.75 for the bulk IL and aq. PAlAm, respectively), and comparable to the A.A. (1.6 - 2.5) of 20% - 30% monoethanolamine solution which is commonly used in industrial application.
文摘A laser trapping-microspectroscopy technique combined with excitation energy transfer from a fluorescent cationic dye (Rhodamine B, RB+) to a non-fluorescent cationic dye (Malachite Green, MG+) was employed to study pH effects on the diffusion coefficients of MG+ (D(MG+)) in single cation-exchange resin microparticles with the diameters of 16 μm. When RB+-pre-adsorbed resin particles were soaked in an aqueous MG+ solution, the RB+ fluorescence was quenched gradually with the soaking time. The time course of the quenching efficiency of RB+ by MG+ was then used to evaluate the D(MG+) value in the particle. The D(MG+) value increased from 1.1 × 10-11 to 4.3 × 10-11 cm2.s–1 on going the solu- tion pH value from 9 to 4. The results were explained reasonably by a Donnan electric potential model.
基金supported in part by MEXT/JSPS KAK-ENHI grants 23H02036(G.K.)JP23H04631,JP23K26670,JP23H03833,JP24K01471,JP24K01515(K.M.)+8 种基金JP23K01977,JP23K20039,JP25K01678(K.O.)24K08341(S.S.)Toyota Riken Scholar(K.M.)the Yoshida Aca-demic and Educational Promotion Foundation(K.M.)the Environment Research and Technology Development Fund(grant number 3RA-2502)of the Environmental Restoration and Conservation Agency provided by Ministry of the Environment of Japan(K.M.)Kyushu University Platform of Inter-/Transdisciplinary Energy Research(Q-PIT)Module-Research Program(K.M.)Kyushu University Integrated Initiative for Designing Future Society(K.M.)JST SPRING,Grant Number JPMJSP2180(T.T.)Network Joint Research Center for Materials and Devices(20253036)(K.I.)The Creative Research Encouragement Award,School of Materials and Chemical Technology,Institute of Science Tokyo(G.K.)。
文摘Aggregation-induced emission luminogens(AIEgens)are typically largeπ-conjugated molecules,but their low affinity and noninvasiveness toward analytes limit practical applications.To address this,smaller,more planar AIEgens are needed.Stilbene,though structurally suitable,lacks visible luminescence.Here,we report a minimally modified stilbene-based AIEgen-4-dipropylamino-4'-cyano-bridged stilbene(DpCBS[7])-that exhibits fluorescence solvatochromism and efficient AIE across a broad polarity range in the visible region.DpCBS[7]exhibits low quantum yields(Φ_(fl)=0.010.04)in solvents from nonpolar n-hexane to polar dimethyl sulfoxide,with large Stokes shifts,viscosity-sensitive luminescence,and highly efficient solid-state luminescence(Φ_(fl)=0.70).To elucidate its dual solvatochromic and AiE behavior,femtosecond transient absorption spectroscopy was conducted.In solution,DpCBS[7]displays transient absorption with lifetimes of 21 ps(toluene)and 56 ps(acetonitrile)at 293 K,indicating ultrafast nonradiative decay leading to low Φ_(fl).Arrhenius analysis over the temperature range of 263-313 K revealed activation energies(ΔE_(a))of 9.90kJ/mol in toluene and 12.8 kJ/mol in acetonitrile for the S_(1)→S_(0) decay of DpCBS[7].The ΔE_(a) values show no clear systematic dependence on solvent polarity.In contrast,pre-exponential factor A remains consistently high regardless of solvent polarity,indicating that the striking photophysical response is governed primarily by the pre-exponential factor rather than by modulation of the activation energy.These findings highlight the fundamental importance of tailoring the distribution function through structural modification as a robust strategy to control AiE characteristics.
基金supported in part by MEXT/JSPS KAKENHI grants 23K26729(GK),25K22304(GK),23K26573(HY).
文摘Circularly polarized luminescence(CPL)has attracted considerable attention owing to its wide range of potential applications.Cholesteric liquid crystals(CLCs)are promising candidates for CPL-active materials because of their ease of fabrication,stimulus responsiveness,and ability to achieve high dissymmetry factors(|g_(lum)|).In most studies on CPL-active CLCs,non-mesogenic luminophores are doped into commercially available liquid crystals(LCs).However,their low solubility in LCs(typically only a few wt%)and their tendency to disrupt LC alignment present challenges in achieving high|glum|values-particularly in thin cells-and in broadening the CPL spectra.Here,we report a new LC mixture comprising our previously designed mesogenic fluorophore and a commercially available LC.This strategy enables a markedly increased luminophore loading(up to∼50 wt%)and enhances the birefringence of the LC matrix.As a result,we achieved a notably high|glum|value of 1.25 even in thin cells(2μm),together with significantly broadened CPL spectra.Furthermore,the emission wavelength was successfully tuned via Förster resonance energy transfer.This work demonstrates a rational design strategy for LC mixtures that yield CPL materials with high|g_(lum)|,advances the fundamental understanding of CPL generation in photoluminescent CLCs,and highlights their potential for future photonic and optoelectronic applications.
文摘Arsenic(As)speciation for the phytoremediation by the Chinese brake fern was studied.In particular,the mechanism of how plants induce compounds containing thiol(SH)and proteins by As exposure in terms of the relationship between As and phosphate uptaken into plant cells was examined.Pteris vittata callus could effciently reduce As(V)to As(III)by the rapid introduction of reductase and synthesize thiols leading to phytochelatins production.Furthermore,Pteris vittata could control phosphate concentration in t...
基金financially supported by the National Natural Science Foundation of China(51861135203,91934303)the Innovative Research Team Program by the Ministry of Education of China(IRT_17R54)the Topnotch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)。
文摘Two-dimensional graphene and its derivatives exhibiting distinct physiochemical properties are intriguing building blocks for researchers from a large variety of scientific fields.Assembling graphene-based materials into membrane layers brings great potentials for high-efficiency membrane processes.Particularly,pervaporation by graphene-based membranes has been intensively studied with respect to the membrane design and preparation.This review aims to provide an overview on the graphene-based membranes for pervaporation processes ranged from fabrication to application.Physical or chemical decoration of graphene-based materials is elaborated regarding their effects on the microstructure and performance.The mass transport of pervaporation through graphene-based membranes is introduced,and relevant mechanisms are described.Furthermore,performances of state-of-the-art graphene-based membranes for different pervaporation applications are summarized.Finally,the perspectives of current challenges and future directions are presented.
基金supported by a UGC collaborative research grant(Award No:CRG-78/79-S&T-01)and also supported by H-Plant Nepal Private Limited.
文摘Background:Murraya koenigii(L.)Spreng.(Rutaceae)is an evergreen shrub distributed over the sub-tropical to lower temperate climatic zone of Nepal which has been used as spice in culinary practice and traditionally being used to treat bites of poisonous animals,dysentery,skin diseases,vomiting,diarrhea,and inflammations.Objective:The main objective of this study is to study the enzyme inhibition potential of different extracts of M.koenigii leaves collected from western Nepal.Methods:Total flavonoid content,total phenolic content,in vitro antioxidant,𝛼α-amylase,lipase,elastase,tyrosinase,and cholinesterase inhibition activities analysis of M.koenigii in ethyl acetate,methanol,and water extract were evaluated.In addition,high-resolution mass spectrometry-based profiling of flavonoid molecules and their docking analysis were performed.Results:Results revealed the noteworthy radical scavenging activity of ethyl acetate extract against ABTS and DPPH.Among the analyzed enzymes,M.koenigii extracts revealed the highest inhibitory potential towards acetylcholinesterase(AChE)and butyrylcholinesterase(BChE)and only water extract showed the inhibition of tyrosinase.The HPLC-ESI-QTOF-MS analysis revealed the presence of Rutin,Quercetin,Ferulic acid,Hyperoside,Kaempferol-7-O-glucoside,and Morin in M.koenigii.Further,in silico docking analysis revealed the significant binding energy of these flavonoid molecules;especially Rutin with BChE.Conclusion:The ethyl acetate and methanolic extracts of M.koenigii showed paramount flavonoid and phenolic content along with noteworthy potential towardsthe inhibition of neuro-degradative enzymes such as BChE which can be characterized further for pharmacological applications.Further study on the isolation of metabolites and their pharmacological properties from M.koenigii is recommended.
文摘Our previous research showed that aliphatic amines were put in order of high reactivity as “ethylamine > ammonia > t-butylamine > diethylamine” on the aromatic nucleophilic substitution of 1-dimetylamino-2,4-bis(trifluoroacetyl)-naphthalene 1 in acetonitrile. The DFT calculation study (B3LYP/6-31G* with solvation model) for the reactions of 1 with above four amines rationally explained the difference of each amines reactivity based on the energies of their Meisenheimer complexes 3 which are assumed to formed as the reaction intermediates in the course of the reaction giving the corresponding N-N exchange products 2. Intramolecular hydrogen bond between amino proton in 1-amino group and carbonyl oxygen in 2-trifluoroacetyl group stabilizes Meisenheimer complexes 3 effectively, and accelerates the substitution reaction from 1 to 2. Our calculation results also predicted that the above order of amines is also true if less polar toluene is used as a solvent instead of acetonitrile even though more enhanced conditions are required.
