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1.
The complex salt named Prussian Blue, Fe 4[Fe(CN) 6] 3?15 H 2O, can release cyanide at pH>10. From the point of view of the origin of life, this fact is of interest, since the oligomers of HCN, formed in the presence of ammonium or amines, leads to a variety of biomolecules. In this work, for the first time, the thermal wet decomposition of Prussian Blue was studied. To establish the influence of temperature and reaction time on the ability of Prussian Blue to release cyanide and to subsequently generate other compounds, suspensions of Prussian Blue were heated at temperatures from room temperature to 150° at pH 12 in NH 3 environment for several days. The NH 3 wet decomposition of Prussian Blue generated hematite, α‐Fe 2O 3, the soluble complex salt (NH 4) 4[Fe(CN 6)]?1.5 H 2O, and several organic compounds, the nature and yield of which depend on the experimental conditions. Urea, lactic acid, 5,5‐dimethylhydantoin, and several amino acids and carboxylic acids were identified by their trimethylsilyl (TMS) derivatives. HCN, cyanogen (C 2N 2), and formamide (HCONH 2) were detected in the gas phase by GC/MS analysis. 相似文献
2.
A series of metal complexes containing the 4-methylumbelliferone-8-methyleneiminodiacetic acid (H 3muia, also named as Calcein Blue) has been synthesized and characterized. Complexes of Cu(II), Ni(II), Mn(II), Zn(II) and Mg(II) have been structurally characterized while Ca(II) and Al(III) complexes by elemental analysis and thermogravimetry. The Cu(II) and Ni(II) complexes are neutral and mononuclear in the solid state. Interestingly, the Mn(II), Zn(II) and Mg(II) muia complexes exist as ion-pairs containing hydrated or solvated metal cation and dimeric metal(II) muia anions. Owing to the presence of hydrogen-bond donors and acceptors in the ligand, hydrogen bonding interactions are dominant along with π-π stacking in their solid-state structures. The solid-state fluorescence studies indicate that the family of muia complexes exhibit comparable emission properties as in solution state, in which only main group and post-transition complexes show bright blue fluorescence while transition metal complexes do not fluoresce. 相似文献
3.
Effective in situ staining of crustacean nerves was achieved with leuco methylene blue reduced with either ascorbic acid or sodium hydrosulfite (Na 2S 2O 4). A stock solution of methylene blue, 0.4% ( ca. 0.001 M), and the reductants, ascorbic acid or sodium hydrosulfite (0.01 M), were prepared in van Harreveld's crayfish physiological solution. Methylene blue stock solution was mixed with either of the reductants in the approximate ratio of 1:10, v/v, and titrated to the end point. Ascorbic acid reduction is light catalyzed and requires intense illumination during titration. The cleared or leucomethylene blue stock solution is suitable for immediate use as a working nerve stain. With either reductant, the working solution oxidizes on standing in air, but can be titrated repeatedly without loss of staining properties. Dissected nerve trunks or tissue were immersed in the working stain for 20 min at room temperature and the staining process observed until suitable contrast developed. Excess dye was decanted and the tissues flooded with crayfish physiological solution. Contrast could sometimes be enhanced by flooding the stained area with 1% hydrogen peroxide in van Harreveld's solution. When permanent mounts were prepared, tissues were dehydrated with tertiary butyl alcohol in preference to ethyl alcohol series. For anatomical and neurophysiological studies of nerve distribution in crustaceans, the alternative use of either ascorbic acid or sodium hydrosulfite, as reductants for methylene blue, was preferable to the more complicated rongalit-technique and characterization of neural elements was fully as satisfactory. 相似文献
4.
Guard cell protoplasts from Commelina communis L. illuminated with red light responded to a blue light pulse by an H + extrusion which lasted for about 10 minutes. This proton extrusion was accompanied by an O 2 uptake with a 4H + to O 2 ratio. The response to blue light was nil in darkness without a preillumination period of red light and increased with the duration of the red light illumination until about 40 minutes. However, acidification in response to a pulse of blue light was obtained in darkness when external NADH (1 millimolar) was added to the incubation medium, suggesting that redox equivalents necessary for the expression of the response to blue light in darkness may be supplied via red light. In accordance with this hypothesis, the photosystem II inhibitor 3-(3,4-dichlorophenyl)-1, 1-dimethylurea (10 micromolar) decreased the acidification in response to blue light more efficiently when it was added before red light illumination than before the blue light pulse. In the presence of hexacyanoferrate, the acidification in response to a blue light pulse was partly inhibited (53% of control), suggesting a competition for reducing power between ferricyanide reduction and the response to blue light. 相似文献
5.
Defective colloids of blue MoO x nanosheets were prepared by anodizing exfoliation method in water. This colloidal solution exhibits an optical plasmonic absorption band in the infrared region at about 760 nm. Merely mixing HAuCl 4 solution with the MoO x leads to loss of the blue color, decaying of 760 nm plasmonic peak and simultaneous formation of the gold plasmon absorption peak at 550–570 nm. Some spectral variations in gold plasmonic peak and MoO x optical band gap were observed for Mo:Au ratio of 10:1, 20:1, 30:1, and 40:1. The size of the gold nanoparticles was in the 5–6 nm range with fcc crystalline structure. X-ray photoelectron spectroscopy (XPS) revealed that the initial solution contains Mo 5+ states and hydroxyl groups, which after reduction, hydroxyl groups are eliminated and the Mo 5+ states converted to Mo 6+. The obtained Au-MoO 3 colloids have a gasochromic property in which they are colored back to blue in the presence of hydrogen gas and the molybdenum oxide absorption peak recovered again. Furthermore, it was observed that both gold and Mo oxide plasmonic peaks redshift by insertion of hydrogen gas which is attributed to change in solution refractive index and formation of defect concentration. 相似文献
6.
Through its impact on photosynthesis and morphogenesis, light is the environmental factor that most affects plant architecture. Using light rather than chemicals to manage plant architecture could reduce the impact on the environment. However, the understanding of how light modulates plant architecture is still poor and further research is needed. To address this question, we examined the development of two rose cultivars, Rosa hybrida‘Radrazz’ and Rosa chinensis‘Old Blush’, cultivated under two light qualities. Plants were grown from one‐node cuttings for 6 weeks under white or blue light at equal photosynthetic efficiencies. While plant development was totally inhibited in darkness, blue light could sustain full development from bud burst until flowering. Blue light reduced the net CO 2 assimilation rate of fully expanded leaves in both cultivars, despite increasing stomatal conductance and intercellular CO 2 concentrations. In ‘Radrazz’, the reduction in CO 2 assimilation under blue light was related to a decrease in photosynthetic pigment content, while in both cultivars, the chl a/ b ratio increased. Surprisingly, blue light could induce the same organogenetic activity of the shoot apical meristem, growth of the metamers and flower development as white light. The normal development of rose plants under blue light reveals the strong adaptive properties of rose plants to their light environment. It also indicates that photomorphogenetic processes can all be triggered by blue wavelengths and that despite a lower assimilation rate, blue light can provide sufficient energy via photosynthesis to sustain normal growth and development in roses. 相似文献
7.
Efficient utilization of methane via catalytic complete combustion is a very important pathway to realize energy efficiency and pollution reduction. From the viewpoint of structural design, herein a green water‐phase route is developed to prepare ultrathin Co(OH) 2 nanosheet supported Pd catalysts. As a platform, the as‐obtained Pd/Co(OH) 2 nanosheets are able to be further used to load CeO 2 nanoparticles to form 2D nanostructured Pd/CeO 2/Co(OH) 2 multicomponent hybrids, and further calcination can result in the final well‐crystallized ultrathin Co 3O 4 nanosheet supported PdO/CeO 2 catalysts. Catalytic tests on methane combustion reveal that CeO 2 as a catalytic assistant greatly boosts the catalytic performance of PdO/Co 3O 4 via strong synergetic effects with Pd species and Co 3O 4 components. The best sample of PdO/CeO 2‐0.1/Co 3O 4 exhibits surprisingly enhanced light‐off activity, indicating that such 2D Co 3O 4 nanosheet supported nanocatalysts might show promising prospect for heterogeneous catalysis. 相似文献
8.
The remarkable properties of pristine B3O3 nanosheet as a nanocarrier for adsorption and desorption of TEPA anticancer drug for designing potential drug delivery platform were investigated using periodic DFT calculations. We studied the adsorption energy of all stable complexes formed between the drug molecule and B3O3 in gas and aqueous phases along with electronic structure analysis of complexes. Different adsorption configurations were studied for drug/B3O3 complexes, including the interaction of the C atom of the triangular ring, O atom in the TEPA drug with the B atom in B3O3, and indirect drug interaction the middle of the R1 ring cavity of the B3O3 nanosheet. The take-up of TEPA prompts a substantial change of 68.13% in the band gap (Eg) of the B3O3 nanosheet in the most stable complex. The present study results affirmed the application of B3O3 nanosheet as a potential vehicle for TEPA drugs in the treatment of cancerous tissues. 相似文献
9.
Developing low‐cost and efficient electrocatalysts for the oxygen evolution reaction and oxygen reduction reaction is of critical significance to the practical application of some emerging energy storage and conversion devices (e.g., metal–air batteries, water electrolyzers, and fuel cells). Lithium cobalt oxide is a promising nonprecious metal‐based electrocatalyst for oxygen electrocatalysis; its activity, however, is still far from the requirements of practical applications. Here, a new LiCoO 2‐based electrocatalyst with nanosheet morphology is developed by a combination of Mg doping and shear force‐assisted exfoliation strategies toward enhanced oxygen reduction and evolution reaction kinetics. It is demonstrated that the coupling effect of Mg doping and the exfoliation can effectively modulate the electronic structure of LiCoO 2, in which Co 3+ can be partially oxidized to Co 4+ and the Co–O covalency can be enhanced, which is closely associated with the improvement of intrinsic activity. Meanwhile, the unique nanosheet morphology also helps to expose more active Co species. This work offers new insights into deploying the electronic structure engineering strategy for the development of efficient and durable catalysts for energy applications. 相似文献
10.
The conversion and transmission of blue energy in the ocean are critical issues. By employing triboelectric nanogenerators (TENGs), blue energy can be harvested but the corresponding electricity transmission and storage are still great challenges. In this work, an automatic high‐efficiency self‐powered energy collection and conversion system is proposed that converts blue energy to chemical energy. A gear‐driven unidirectional acceleration TENG is designed to convert disordered and low‐frequency water wave energy to low voltage and high current DC output. The output bias from the TENG can be used to drive a Ti–Fe 2O 3/FeNiOOH based photoelectrochemical cell under sunlight to produce hydrogen. Moreover, under the situation without sunlight, the self‐powered system can be automatically switched to another working state to charge a Co 3O 4 based lithium‐ion battery. The hydrogen production rate reaches to 4.65 µL min ‐1 under sunlight at the rotation speed of 120 rpm. The conversion efficiency of the whole system is calculated to be 2.29%. The system triggered by photoswitches can automatically switch between two working states with or without sunlight and convert the blue energy to either hydrogen energy or battery energy for easy storage and transmission, which widens the future applications for blue energy. 相似文献
11.
In this contribution, a significant catalyst based on spinel ZnMn 2O 4 composite nanoparticles has been developed for electro-catalysis of nitrophenol and photo-catalysis of brilliant cresyl blue. ZnMn 2O 4 composite (hetaerolite) nanoparticles were prepared by easy low temperature hydrothermal procedure and structurally characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and UV-visible spectroscopy which illustrate that the prepared material is optical active and composed of well crystalline body-centered tetragonal nanoparticles with average size of ∼38±10 nm. Hetaerolite nanoparticles were applied for the advancement of a nitrophenol sensor which exhibited high sensitivity (1.500 µAcm −2 mM −1), stability, repeatability and lower limit of detection (20.0 µM) in short response time (10 sec). Moreover, hetaerolite nanoparticles executed high solar photo-catalytic degradation when applied to brilliant cresyl blue under visible light. 相似文献
12.
A series blue phosphorescent emitting materials based on 2-(fluoro substituted phenyl)-4-methylpyridine as the cyclometalated ligands have been synthesized and characterized. The complexes have the general structure (C ^N) 2Ir(pic), where C ^N is a monoanionic cyclometalating ligand (e.g., 2-(2,4-difluorophenyl)-4-methylpyridine (24f 2pmpyH), 2-(3,4-difluorophenyl)-4-methylpyridine (34f 2pmpyH), 2-(3,5-difluorophenyl)-4-methylpyridine (35f 2pmpyH), and 2-(3,4,5-trifluorophenyl)-4-methyl-pyridine (345f 3pmpyH)), pic is 2-picolinic acid. The absorption, emission, cyclic voltammetry and thermostability of the complexes were systematically investigated. The (46f 2pmpy) 2Ir(pic) has been characterized using X-ray crystallography and the electronic ground state calculated using B3LYP density functional theory. HOMO levels are a mixture of Ir and 2-(fluoro phenyl)-4-methylpyridine ligand orbitals, while the LUMO is predominantly pic ligand based. Introduction of fluorine atoms and methyl group into ppy ligand and changing in position of F substituents in phenyl ring can finely tune emission of the complexes, showing bright blue-to-green luminescence at a wavelength of 463-501 nm at room temperature in CH 2Cl 2. 相似文献
13.
Few‐layer MoS 2 nanosheets are successfully synthesized using a simple and scalable ultrasonic exfoliation technique. The thicknesses of the MoS 2 nanosheets ares about 10 nm as measured by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The unique nanosheet architecture renders the high‐rate transportation of sodium ions due to the short diffusion paths provided by ultrathin thickness and the large interlayer space within the MoS 2 crystal structure ( d(002) = 6.38 Å). When applied as anode materials in sodium‐ion batteries, MoS 2 nanosheets exhibit a high, reversible sodium storage capacity and excellent cyclability. The MoS 2 nanosheets also demonstrate good electrochemical performance at high current densities. 相似文献
14.
In caulonemal filaments of the moss, Physcomitrella patens, which had been incubated in darkness, 3 s irradiation with blue light (λ max 450 nm) at fluence rates of 100 μmol m −2 s −1 and above caused a transient␣increase in cytosolic calcium ion concentration, [Ca 2+] cyt, which was both intensity- and time-dependent. Measurements of [Ca 2+] cyt were made using moss transformed with the cDNA for apoaequorin and reconstituting the Ca 2+-dependent photoprotein aequorin in the cytosol by incubation in coelenterazine.␣In response to blue light at fluence rates
of 100–1000 μmol photons m −2 s −1, [Ca 2+] cyt increased transiently from a basal level of approximately 50 nM to between 200 and 700 nM. Irradiation with red light did
not evoke any measurable change in [Ca 2+] cyt. The presence of calcium in the incubating medium was not required for the increase in [Ca 2+] cyt to occur. A mutant strain, gad-139, was identified which required an irradiance of only 1 s to evoke a response. The kinetics showed a delay of approximately
6 s from the beginning of illumination before the beginning of the increase in [Ca 2+] cyt. The data suggest that the activation of a photoreceptor rather than the direct opening of calcium channels is involved in
this blue-light response.
Received: 4 December 1997 / Accepted: 4 May 1998 相似文献
15.
The temperature dependence of respiration rates and their acclimation to growth temperature vary among species/ecotypes, but the details remain unclear. Here, we compared the temperature dependence of shoot O 2 consumption rates among Arabidopsis thaliana ecotypes to clarify how the temperature dependence and their acclimation to temperature differ among ecotypes, and how these differences relate to shoot growth. We examined growth analysis, temperature dependence of O 2 consumption rates, and protein amounts of the respiratory chain components in shoots of twelve ecotypes of A. thaliana grown at three different temperatures. The temperature dependence of the O 2 consumption rates were fitted to the modified Arrhenius model. The dynamic response of activation energy to measurement temperature was different among growth temperatures, suggesting that the plasticity of respiratory flux to temperatures differs among growth temperatures. The similar values of activation energy at growth temperature among ecotypes suggest that a similar process may determine the O 2 consumption rates at the growth temperature in any ecotype. These results suggest that the growth temperature affects not only the absolute rate of O 2 consumption but also the plasticity of respiratory flux in response to temperature, supporting the acclimation of shoot growth to various temperatures. 相似文献
16.
The simple preparation of Co 3O 4 nanoparticles from a solid organometallic molecular precursor N- N′-bis(salicylaldehyde)-1,2-phenylenediimino cobalt(II); Co(salophen) has been achieved via two simple steps: firstly, the Co(salophen) precursor was precipitated from the reaction of cobalt(II) acetate and N- N′-bis(salicylaldehyde)-1,2-phenylenediimino; H 2salophen; in propanol under nitrogen condition; then, cubic phase Co 3O 4 nanoparticles with the size of mostly 30-50 nm could be produced by thermal treatment of the Co(salophen) in air at 773 K for 5 h. The as-synthesized products were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and scanning electronic microscopy (SEM). These results confirm that the resulting oxide was pure single-crystalline Co 3O 4 nanoparticles. The optical property test indicates that the absorption peak of the nanoparticles shifts towards short wavelength, and the blue shift phenomenon might be ascribed to the quantum effect. The hysteresis loops of the obtained samples reveal the ferromagnetic behaviors the enhanced coercivity ( Hc) and decreased saturation magnetization ( Ms) in contrast to their respective bulk materials. 相似文献
17.
Reports describing production of reactive oxygen species in neonatal heart are missing. As lysyl oxidase is potentially important source of H 2O 2, we studied its role during ontogenic development of rat heart. H 2O 2 was detected in thin sections of developing rat heart by fluorescence microscopy with the use of fluorescence probe 2??-7??-dichlorofluorescin. The experimental design comprised foetuses 21 days after conception, and then the animals sampled on the 1st, 4th, 7th, 10th, 15th, 30th and 60th day after birth. We also used 7-month-old animals as an example of ageing effects. Since the day 4 on, H 2O 2 was produced only extracellularly up to the day 15, between days 30 and 60 intracellular production was detected as well, and in 7-month-old animals only extracellular production was observed. The specific inhibitors of lysyl oxidase almost completely quenched the H 2O 2-dependent fluorescence. Starting from day 7, blue autofluorescence specific to oxidized proteins developed in the vessel wall. Intracellular blue autofluorescence specific to autoxidation products developed after day 30. Chloroform extraction diminished the intracellular blue fluorescence, leaving the extracellular fluorescence intact. This confirmed the protein nature of the fluorophores. Lysyl oxidase is significant source of H 2O 2 in the heart vessel wall during development and H 2O 2 oxidatively modifies elastin producing protein blue autofluorescence. 相似文献
18.
Cells of certain Chlamydomonas reinhardtii strains dramatically swell and ultimately disintegrate when grown in the dark but not in the light. This effect of darkness is delayed: cells undergo about two divisions before swelling. Measurements on O 2 uptake and ATP content indicate that the cells grown in the dark are not deficient in energy supply. Dim blue light not effective in photosynthesis prevents `dark-lethality'. Inhibition of protein synthesis during the latent period with cycloheximide also prevents dark-lethality. We propose that blue light stimulates synthesis of one or more proteins which are part of or are important in assembly of an osmoregulatory complex. 相似文献
19.
Energy storage phosphors with millisecond period afterglow that compensate for the diming time of alternating current light‐emitting diodes (AC‐LEDs) have promising application. To obtain a persistent luminescence (PersL) white colour in AC‐LEDs, we focussed on a red afterglow with short period phosphorescence. Ca 4Ti 3O 10 forms a type of perovskite‐related Ruddlesden–Popper phase structure. Doping Pr 3+ ions into Ca 4Ti 3O 10, an ideal red PersL was obtained. X‐ray diffraction and element analysis demonstrated that our target samples were crystallized well. Steady‐state and afterglow luminescence properties were investigated in detail. Notably, the PersL intensity was dependent on various excitation wavelengths. By measuring three‐dimensional thermoluminescence spectra, we found that the trap depths showed a continuous distribution and that the shallowest trap contributed to the millisecond afterglow. Two PersL mechanism models were used to elucidate the electron charging and de‐trapping processes under UV or blue light activation. 相似文献
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