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DNA oligonucleotides with a 5-base mutation at the 3'-terminus were investigated by terahertz (THz) spectroscopy in a marker-free manner. The four single-stranded oligonucleotides with 17nt have been detected with specificity on a microfluidic chip, and corroborated by spectral measurements with split-ring resonators. The number of hydrogen bonds formed between the oligonucleotide and its surrounding water molecules, deemed a key contribution to the THz absorption of biological solutions, was explored by molecular dynamics simulations to explain the experimental findings. Our work underlies the feasibility of THz spectroscopy combined with microstructures for marker-free detection of DNA, which may form the basis of a prospective diagnostic tool for studying genic mutation.

Reduced graphene oxide (RGO) has proved to be a promising candidate in high‐performance gas sensing in ambient conditions. However, trace detection of different kinds of gases with simultaneously high sensitivity and selectivity is challenging. Here, a chemiresistor‐type sensor based on 3D sulfonated RGO hydrogel (S‐RGOH) is reported, which can detect a variety of important gases with high sensitivity, boosted selectivity, fast response, and good reversibility. The NaHSO3 functionalized RGOH displays remarkable 118.6 and 58.9 times higher responses to NO2 and NH3, respectively, compared with its unmodified RGOH counterpart. In addition, the S‐RGOH sensor is highly responsive to volatile organic compounds. More importantly, the characteristic patterns on the linearly fitted response–temperature curves are employed to distinguish various gases for the first time. The temperature of the sensor is elevated rapidly by an imbedded microheater with little power consumption. The 3D S‐RGOH is characterized and the sensing mechanisms are proposed. This work gains new insights into boosting the sensitivity of detecting various gases by combining chemical modification and 3D structural engineering of RGO, and improving the selectivity of gas sensing by employing temperature dependent response characteristics of RGO for different gases. A one‐step self‐assembled 3D sulfonated reduced graphene oxide hydrogel (S‐RGOH) is developed to detect various important gaseous chemicals with high performance. The S‐RGOH sensor displays remarkable 118.6 and 58.9 times higher responses to NO2 and NH3, respectively, compared with the unmodified counterpart. An imbedded microheater is employed to differentiate various gases by identifying the characteristic patterns on the fitted response–temperature curves.

Background: Maize (Zea mays L.) is a vital global crop, and yield improvement through dwarfing breeding—inspired by the Green Revolution—holds promise for addressing food security challenges. Despite the identification of over 60 dwarf genes in maize, their genetic diversity remains limited. Brassinosteroids (BRs) are key phytohormones that regulate plant height, and mutations in BR-related genes often result in dwarf phenotypes. Methods: The zmbrd1 mutant was generated via EMS mutagenesis in the B73 background. Phenotypic traits (plant height, root length) and histological features (e.g., mesocotyl cell length) were compared between mutant and wild-type plants. Transcriptome sequencing of leaves and root tips identified differentially expressed genes (DEGs), followed by GO and KEGG enrichment analyses. Key hormone-related genes were validated by means of qRT-PCR. Results: The zmbrd1 mutant exhibited severe dwarfism and reduced root length, primarily due to inhibited longitudinal cell elongation in internodes. Transcriptome analysis revealed 1652 DEGs in leaves and 1450 DEGs in roots. Enriched pathways included BR biosynthesis, plant hormone signal transduction, and glutathione metabolism. In leaves, upregulated genes were linked to hormone signaling and chloroplast function, while downregulated genes involved oxidoreductase activity and stress response. In roots, DEGs were enriched in ethylene signaling, MAPK pathways, and plant–pathogen interaction, suggesting impaired defense responses. qRT-PCR confirmed dysregulation of hormone-related genes: GA biosynthesis genes were downregulated, whereas auxin-related genes were upregulated in leaves but downregulated in roots. Conclusions: The dwarf phenotype of zmbrd1 stems from disrupted BR biosynthesis, leading to hormonal imbalance (particularly in GA and auxin pathways), oxidative stress, and suppressed cell elongation. Our results suggest that ZmBRD1 plays a key role in integrating aboveground and underground growth likely through modulating hormone crosstalk. This study elucidates BR-mediated height regulation and provides genetic resources for maize breeding.

Urban areas with parks tend to have the best outdoor thermal comfort in regions with high urban heat island effects during summer. This study analyzed the synergistic cooling effects of 94 urban parks and the adjacent built-up areas in six districts of Xi’an City using four cooling indicators: park cooling intensity (PCI), park cooling area (PCA), park cooling effect (PCE), and park cooling gradient (PCG). The results showed that 84 out of 94 parks exhibited significant cooling effects, with an average PCI of 1.98 °C, PCA of 51.7 ha, PCE of 6.6, and PCG of 8.2 °C/km. Correlation analyses indicated that the intrinsic park attributes, external buffer zone building height, and building density were the main factors affecting the cooling effect. The park landscape configuration, building height, and density significantly influenced the PCI and PCG, while the park shape and size were crucial for the PCA (positive) and PCE (negative). The optimal park areas for improving the thermal environment were identified as 26 ha (cooling area focus, building density <13%) and 15 ha (cooling intensity focus, building height <21 m, density >32%). This study provides theoretical guidance for planning urban parks and the surrounding areas based on cooling effects, offering insights for future climate resilience planning.

In this paper, a high-efficiency terahertz amplitude modulation device based on a field-effect transistor has been proposed. The polarization insensitive modulator is designed to achieve a maximum experimental modulation depth of about 53% within 5 V of gate voltages using monolayer graphene. Moreover, the manufacturing processes are inexpensive. Two methods are adopted to improve modulation performance. For one thing, the metal metamaterial designed can effectively enhance the electromagnetic field near single-layer graphene and therefore greatly promote the graphene’s modulation ability in terahertz. For another, polyethylene oxide-based electrolytes (PEO:LiClO4) acts as a high-capacity donor, which makes it possible to dope single-layer graphene at a relatively low voltage.

In this study, double-sided polymer surface nanostructures are fabricated using twice nanoimprint lithography and metal deposition technique. We perform electrical property measurement on these double-sided surface nanostructures. Open-circuit voltage and short-circuit current of the as-prepared samples with double-sided surface nanostructures and conductive electrode are recorded using an oscilloscope with applying different external force. The measurements are carried out at room temperature. We find that the intensity of open-circuit voltage and short-circuit current for the double-sided surface nanostructures depends strongly on the sizes, shapes, and arrangements of nanostructures and pressure force. The strongest electrical property can be observed in the hexagon nanopillar arrays with the diameter of about 400 nm containing sub-50-nm resolution sharp structures at the force of about 40 N. We discuss the physical mechanisms responsible for these interesting research findings. The experimental results we study are relevant to the applications of double-sided surface nanostructures such as a nanogenerator, pressure sensors, and nano-optoelectronic devices.

Leaf rolling is a common phenotypic trait and has recently gained more attention due to its involvement in photosynthetic efficiency and crop yield. An upward-curling leaf mutant ( Bnucl1 ) was obtained from the rapeseed cultivar Zhongshuang 9 population ( Brassica napus L.) via ethyl methanesulfonate mutagenesis. In this study, morphological and histological features, physiological characters, and inheritance of the Bnucl1 were investigated. The results indicated that leaf structure such as midvein, epidermal cells, and palisade mesophyll cells displayed remarkable differences in the mutant compared to wild type (WT) . Pronounced variations in the chloroplast size and shape, starch grana between the mutant and WT leaves were observed, and the chloroplasts might be largely undifferentiated in the mutant. Moreover, the net photosynthetic rate, stomatal conductance, intercellular CO 2 concentration, and transpiration rate were significantly decreased in the mutant. Likewise, chlorophyll a , chlorophyll b , total chlorophyll, and carotenoid contents were also significantly decreased in the mutant compared to WT. Enzyme activity of SOD, POD, and CAT was reduced; however, the content of H 2 O 2 and MDA was increased in the mutant. Among the tested agronomic traits and leaf area, all the traits except siliques on the terminal raceme decreased in the mutant plants. Hence, the mutation has imposed remarkable impacts on the structure and function of leaves and agronomic traits. Genetic study indicated that this trait was monogenic and the allele for curling leaf was dominant. These results provide inroads for further evaluation to understand the mechanism of leaf development in B. napus .

This paper proposes a structured model for the identification of green tea, as well as tracing its geographical origins. Considering that the features of different types of green tea are similar under THz time-domain spectroscopy, we designed a program to perform principal component analysis (PCA) of the spectroscopic data of various green tea samples and to determine the data sequences of principal components. We then established a training set for the principal components to train a support vector machine (SVM) model via a genetic algorithm (GA). We used this model to optimize the parameters and develop a GA-based SVM model with an identification rate of 96.25% for the tested samples. Taken together, our results confirm that THz time-domain spectroscopy combined with GA-SVM can be effectively applied to rapidly identify types of green tea with different geographical origins.

An approach to distinguish eight kinds of different human cells by Raman spectroscopy was proposed and demonstrated in this paper. Original spectra of suspension cells in the frequency range of 623~1783 cm−1 were acquired and pre-processed by baseline calibration, and principal component analysis (PCA) was employed to extract the useful spectral information. To develop a robust discrimination model, a linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA) were attempted comparatively in the work. The results showed that the QDA model is better than the LDA model. The optimal QDA model was generated with 12 principal components. The classification rates are 100% in the calibration and prediction set, respectively. From the experimental results, it is concluded that Raman spectroscopy combined with appropriate discriminant analysis methods has significant potential in human cell detection.

Terahertz near-field detection based and imaging on a nanotip has drawn wide attention following extensive applications of terahertz imaging technologies. Through the local enhanced electric field created by a terahertz nanotip in the near field, it is very likely to attain superior detection sensitivity and higher spatial resolution. This paper simulates the local enhancement effects of the terahertz near-field microscopy using a two-dimension finite difference time domain (2D-FDTD) method. Factors that influence the enhancement effects are investigated and analyzed in detail. Simulation results show that the size of the nanotip apex, the apex-substrate distance, dielectric properties of the substrate and the detected sample, etc., have significant impacts on the electric field enhancement and spatial resolution of the terahertz near-field nanotip, which can be explained from the effective polarizability of the nanotip-sample/substrate system.