Solution−Chemical Synthesis of Carbon Nanotube/ZnS Nanoparticle Core/Shell Heterostructures

A facile solution−chemical method has been developed to be capable of encapsulating a multiwalled carbon nanotube (MWCNT) with ZnS nanocrystals without using any bridging species. The thickness of the ZnS shell can be tuned easily by controlling the experimental conditions. The optical properties of the MWCNT/ZnS heterostructures were investigated using UV−vis absorption and photoluminescence spectroscopy. The optical absorption spectrum indicates that the band gap of ZnS nanocrystallites is 4.2 eV. On the basis of the photoluminescence spectrum, charge transfer is thought to proceed from ZnS nanocrystals to the nanotube in the ZnS−carbon nanotube system. These special heterostructures are very easily encapsulated within a uniform silica layer by a modified-Stöber process and still show better stability even after heat treatment at 400 °C, which makes them appealing for practical applications in biochemistry and biodiagnostics

Table_1_Parallel phonological processing of Chinese characters revealed by flankers tasks.XLSX

An important and extensively researched question in the field of reading is whether readers can process multiple words in parallel. An unresolved issue regarding this question is whether the phonological information from foveal and parafoveal words can be processed in parallel, i.e., parallel phonological processing. The present study aims to investigate whether there is parallel phonological processing of Chinese characters. The original and the revised flankers tasks were applied. In both tasks, a foveal target character was presented in isolation in the no-flanker condition, flanked on both sides by a parafoveal homophone in the homophone-flanker condition, and by a non-homophonic character in the unrelated-flanker condition. Participants were instructed to fixate on the target characters and press two keys to indicate whether they knew the target characters (lexical vs. non-lexical). In the original flankers task, the stimuli were presented for 150 ms without a post-mask. In the revised flankers task, we set the stimulus exposure time (duration of the stimuli plus the blank interval between the stimuli and the post-mask) to each participant’s lexical decision threshold to prevent participants from processing the target and flanker characters serially. In both tasks, reaction times to the lexical targets were significantly shorter in the homophone-flanker condition than in the unrelated-flanker condition, suggesting parallel phonological processing of Chinese characters. In the revised flankers task, accuracy rates to the lexical targets were significantly lower in the unrelated-flanker condition compared to the homophone-flanker condition, further supporting parallel phonological processing of Chinese characters. Moreover, reaction times to the lexical targets were the shortest in the no-flanker condition in both tasks, reflecting the attention distribution over both the target and flanker characters. The findings of this study provide valuable insights into the parallel processing mechanisms involved in reading.</p

DNA Guanine Adducts from 3-Methyl-1,2,3-oxadiazolinium Ions

The reaction of 3-methyl-1,2,3-oxadiazolinium tosylate 10, a close model for a putative reactive intermediate in the carcinogenic activation of ethanol nitrosamines such as (2-hydroxyethyl)methylnitrosamine 1, with various guanine derivatives, including acycloguanosine 12, deoxyguanosine, deoxyguanosine monophosphate, and cyclic guanosine monophosphate, various DNA oligomers, and calf-thymus DNA has been examined to determine whether this compound methylates and hydroxyethylates guanine residues as proposed. In all of the transformations, 7-(2-(methylnitrosamino)ethyl)guanine (14) is the major product, following acidic hydrolysis, and exceeds the formation of 7-methylguanine by ratios ranging from 4:1 to 48:1, depending upon the guanine bearing substrate. O6-(2-(Methylnitrosamino)ethyl)deoxyguanosine (20) was prepared from the Mitsunobu coupling of 1 and a protected deoxyguanosine derivative. 20 is not produced in the reaction of 10 and deoxyguanosine and decomposes to 1 and guanine upon mild acid treatment, suggesting possible neighboring group participation in its facile hydrolytic cleavage. All of the major products from the reaction of 10 and 12 have been characterized, including the direct alkylation product, 7-(2-(methylnitrosamino)ethyl)acycloguanosine (13), and N2-(2-(methylnitrosamino)ethyl)guanine, which was independently synthesized. Elucidation of the reactions of DNA with 10 and other electrophiles was facilitated by the development of both partial and total enzymatic hydrolysis assays utilizing 32P-5‘-labeled DNA oligotetramers containing one of each base type and HPLC with radiometric detection. The partial hydrolysis assay gives information as to the type of base being modified, and the total hydrolysis assay permits a determination of the number of adducts produced for a given base. The assays permit a comparison between reactions where the same type of base adduct could be expected. Comparisons of the reactions of ethylene oxide and 10 using this methodology showed that 10 does not hydroxyethylate guanine in DNA

Synthesis of Mesoporous Eu₂O₃ Microspindles

Mesoporous Eu2O3 microspindles have been prepared by a facile solution process followed by subsequent heat treatment. By adding urea stepwise and varying the reaction time, the dimension of the Eu2O3 microspindles can be easily tuned from 250 × 100 nm to 900 × 400 nm. The products were characterized by X-ray diffraction, small-angle X-ray scattering, (high-resolution) transmission electron microscopy, scanning electron microscopy, N2 adsorption, and photoluminescence spectroscopy. The Eu2O3 samples exhibit a relatively broad pore-size distribution, and the wall of the pore is constructed by well-crystalline Eu2O3 nanocrystals with diameters of about 15 nm. A possible formation mechanism of the mesoporous microspindles was also discussed

Interfacial Confined Formation of Mesoporous Spherical TiO₂ Nanostructures with Improved Photoelectric Conversion Efficiency

Uniform mesoporous TiO2 nanospheres were successfully developed via an interfacial confined formation process for application in dye-sensitized solar cells. The mesoporous spherical structures greatly promote the dye-loading capacity, electron transfer, and light scattering, resulting in remarkable enhancement of the cell performance. The designed interfacial platform caused a reaction-limited aggregation of the TiO2 nanocrystals, resulting in the formation of mesoporous spherical nanostructures with sphere diameter of 216 nm and pore size of 8 nm. The oriented attachment of adjacent TiO2 nanocrystals facilitated the electron transfer process when the mesoporous TiO2 nanospheres were used as electrode films. The dye coverage was enhanced remarkably in the mesoporous spherical TiO2 samples. Owing to the enhanced light-harvesting efficiency, solar conversion efficiency was enhanced about 30% for the dye-sensitized solar cell (DSSC) based on mesoporous spherical TiO2 in comparison with that made by commercial TiO2 nanoparticles

Table_1_Conventionality matters in Chinese metaphor but not simile comprehension: evidence from event-related potentials.XLSX

Metaphor and simile, two prevalent forms of figurative language widely employed in daily communication, serve as significant research subjects in linguistics. The Career of Metaphor Theory in cognitive linguistics posits that as conventionality increases, the cognitive mechanisms of metaphor comprehension shift from “comparison” to “categorization.” In line with this notion, prior electrophysiological investigations have revealed that novel metaphors elicit a stronger N400 brain response compared to conventional metaphors. However, the observed N400 difference between conventional and novel metaphors may merely stem from the familiarity contrast between them, as conventional metaphors are typically more familiar than novel ones. To address this dichotomy, the present study not only compared the N400 responses between conventional and novel metaphors but also between conventional and novel similes. While conventional and novel similes differ in familiarity, similar to conventional and novel metaphors, both are processed via “comparison” mechanisms. The results revealed that novel metaphors elicited larger N400 amplitudes compared to conventional metaphors, aligning with previous findings. In contrast, no significant N400 differences were observed between conventional and novel similes, suggesting that familiarity disparity is unlikely to account for N400 distinctions. Our findings imply that conventional and novel metaphors undergo distinct cognitive processing mechanisms (“comparison” versus “categorization”), thereby providing further empirical validation for the Career of Metaphor Theory.</p

Flame Synthesis of Tin Oxide Nanorods: A Continuous and Scalable Approach

Well-crystalline SnO2 nanorods were first synthesized via a continuous and scalable iron-assisted flame approach with production rate up to 50 g/h in laboratory-scale. The as-prepared SnO2 nanorods with uniform length up to 200 nm and diameter around 20 nm are smooth and single crystal rutile structures, growing along the [001] direction. Iron dopant is incorporated into the SnO2 lattice and selectively effects a specific SnO2 crystal plane, promoting the further crystal oriented growth into nanorods. Meanwhile, the photoluminescence (PL) spectrum of such SnO2 nanorods exhibits a broad, stronger orange-emission peak around 620 nm, suggesting potential applications in optoelectronics. It is noteworthy that this dopant-assisted flame approach provides a new strategy for sequentially engineering one-dimensional nanomaterials

Fabrication of Spherical Multi-Hollow TiO₂ Nanostructures for Photoanode Film with Enhanced Light-Scattering Performance

Spherical multihollow (MH) TiO₂ nanostructures have been synthesized via a microemulsion-based approach with titanium glycerolate complexes formation at glycerol microemulsions interface. The self-aggregation of those microemulsions induces the formation of MH TiO₂ nanospheres. Owing to this hierarchical hollow structure, photoanode films derived from MH TiO₂ nanosphere as light scattering layer exhibits an enhanced light harvesting efficiency, thus leading to a 43% increment of photovoltaic performance compared to that from P25 nanoparticle film

Comparison of the Structural Characteristics of Cellulolytic Enzyme Lignin Preparations Isolated from Wheat Straw Stem and Leaf

Lignin structure has been considered to be an important factor that significantly influences the biorefinery processes. In this work, the effect of ball milling on the structural components and extractable lignin in enzymatic residues was evaluated, and the structural characteristics of the cellulolytic enzyme lignin preparations isolated from wheat straw stem (SCEL) and leaf (LCEL) were comparatively investigated by a combination of nitrobenzene oxidation (NBO), ozonation, infrared spectroscopy, and 1H–13C heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR). The results showed that 4 h ball-milled samples were good enough for structural analysis with high lignin yield. Both CELs are typical p-hydroxyphenyl-guaiacyl-syringyl lignins which are associated with p-coumarates and ferulates. However, the structure of lignin in wheat straw stem is rather different from that in leaf. Compared to stem lignin, leaf lignin has lower product yields of NBO and ozonation, lower erythro/threo ratio, and higher condensation degree. The analysis of 2D HSQC NMR indicated that the S/G ratio of SCEL was 0.8, which is about twice as much as that of LCEL. The flavone tricin is incorporated into both stem and leaf lignins. The content of tricin in LCEL is higher than that in SCEL

The Carcinogenic Significance of Reactive Intermediates Derived from 3-Acetoxy- and 5-Acetoxy-2-hydroxy-<i>N-</i>nitrosomorpholine

N-Nitroso-2-hydroxymorpholine (NHMOR), a relatively reactive metabolite of two potent carcinogens, N-nitrosodiethanolamine (NDELA) and N-nitrosomorpholine (NMOR), has been reported to not be carcinogenic. Two isomeric acetate esters of the α-hydroxynitrosamines expected to be produced from the cytochrome P450-mediated metabolism of NHMOR have been synthesized, and their hydrolytic decomposition products, hydrolysis rates, and deoxyguanosine (dG) reaction adducts have been determined. N-Nitroso-3-acetoxy-2-hydroxymorpholine was prepared in high yield from the reaction of N-nitroso-2,3-dehydromorpholine with dry peracetic acid in glacial acetic acid or by the reaction of its dimethyldioxirane-produced epoxide with glacial acetic acid. The hydrolysis of this α-acetoxynitrosamine gave acetaldehyde (10%), ethylene glycol (55%), glyoxal (95%), and acetic acid. The pH rate profile for the hydrolysis of this nitrosamine was abnormal in that it exhibited pronounced base-catalyzed hydrolysis beginning at pH 5. The mechanism of hydrolytic decomposition is proposed to involve neighboring group participation with the formation of a reactive epoxide intermediate. N-Nitroso-3-acetoxy-2-hydroxymorpholine reacted with dG to give these guanine adducts after acidic deglycosylation:  1,N2-glyoxal (65%), 7-(2-hydroxyethyl)guanine (9%), and O6-hydroxyethylguanine (3%). N-Nitroso-5-acetoxy-2-hydroxymorpholine was synthesized from 2-hydroxyethylvinylnitrosamine by its oxidative conversion to the corresponding aldehyde followed by reaction with dry peracetic acid in glacial acetic. The hydrolytic decomposition products of this nitrosamine were 2-acetoxyacetaldehyde (65%), a rearrangement product, glycol aldehyde (15%), a trace of glyoxal, and acetic acid. The pH rate profile for the hydrolysis of this acetate is similar to other α-acetoxynitrosamines in that it exhibits a pH-independent region which gives way to base-catalyzed ester hydrolysis beginning at pH 7. The lower pH (≈ 7 < 9) onset of base catalysis is proposed to involve base-catalyzed opening of the hemiacetal and intramolecular acyl transfer to give an unstable α-hydroxynitrosamine. N-Nitroso-5-acetoxy-2-hydroxymorpholine was less reactive toward dG and gave the 1,N2-etheno-dG adduct (44%). The products from both of the isomeric α-acetoxy nitrosamines were judged to arise from diazonium ions produced from unstable α-hydroxynitrosamine intermediates. The high yield of the rearrangement product 2-acetoxyacetaldehyde could explain the low carcinogenic potential of NHMOR if it is mainly α-hydroxylated at the 5 carbon. Hydroxylation of NHMOR at carbon 3 is expected to yield a carcinogenic outcome