ACC SYNTHASE4 inhibits gibberellin biosynthesis and FLOWERING LOCUS T expression during citrus flowering.

Flowering is an essential process in fruit trees. Flower number and timing have a substantial impact on the yield and maturity of fruit. Ethylene and gibberellin (GA) play vital roles in flowering, but the mechanism of coordinated regulation of flowering in woody plants by GA and ethylene is still unclear. In this study, a lemon (Citrus limon L. Burm) 1-aminocyclopropane-1-carboxylic acid synthase gene (CiACS4) was overexpressed in Nicotiana tabacum and resulted in late flowering and increased flower number. Further transformation of citrus revealed that ethylene and starch content increased, and soluble sugar content decreased in 35S:CiACS4 lemon. Inhibition of CiACS4 in lemon resulted in effects opposite to that of 35S:CiACS4 in transgenic plants. Overexpression of the CiACS4-interacting protein ETHYLENE RESPONSE FACTOR3 (CiERF3) in N. tabacum resulted in delayed flowering and more flowers. Further experiments revealed that the CiACS4-CiERF3 complex can bind the promoters of FLOWERING LOCUS T (CiFT) and GOLDEN2-LIKE (CiFE) and suppress their expression. Moreover, overexpression of CiFE in N. tabacum led to early flowering and decreased flowers, and ethylene, starch, and soluble sugar contents were opposite to those in 35S:CiACS4 transgenic plants. Interestingly, CiFE also bound the promoter of CiFT. Additionally, GA3 and 1-aminocyclopropanecarboxylic acid (ACC) treatments delayed flowering in adult citrus, and treatment with GA and ethylene inhibitors increased flower number. ACC treatment also inhibited the expression of CiFT and CiFE. This study provides a theoretical basis for the application of ethylene to regulate flower number and mitigate the impacts of extreme weather on citrus yield due to delayed flowering.

2-Hydroxy-5-nitro-3-(trifluoromethyl)pyridine as a Novel Matrix for Enhanced MALDI Imaging of Tissue Metabolites.

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), which is a label-free imaging technique, determines the spatial distribution and relative abundance of versatile endogenous metabolites in tissues. Meanwhile, matrix selection is generally regarded as a pivotal step in MALDI tissue imaging. This study presents the first report of a novel MALDI matrix, 2-hydroxy-5-nitro-3-(trifluoromethyl)pyridine (HNTP), for the in situ detection and imaging of endogenous metabolites in rat liver and brain tissues by MALDI-MS in positive-ion mode. The HNTP matrix exhibits excellent characteristics, including strong ultraviolet absorption, µm-scale matrix crystals, high chemical stability, low background ion interference, and high metabolite ionization efficiency. Notably, the HNTP matrix also shows superior detection capabilities, successfully showing 185 detectable metabolites in rat liver tissue sections. This outperforms the commonly used matrices of 2,5-dihydroxybenzoic acid and 2-mercaptobenzothiazole, which detect 145 and 120 metabolites from the rat liver, respectively. Furthermore, a total of 152 metabolites are effectively detected and imaged in rat brain tissue using the HNTP matrix, and the spatial distribution of these compounds clearly shows the heterogeneity of the rat brain. The results demonstrate that HNTP is a new and powerful positive-ion mode matrix to enhance the analysis of metabolites in biological tissues by MALDI-MSI.

Electromagnetic Field-Assisted Frozen Tissue Planarization Enhances MALDI-MSI in Plant Spatial Omics.

Plant samples with irregular morphology are challenging for longitudinal tissue sectioning. This has restricted the ability to gain insight into some plants using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Herein, we develop a novel technique termed electromagnetic field-assisted frozen tissue planarization (EMFAFTP). This technique involves using a pair of adjustable electromagnets on both sides of a plant tissue. Under an optimized electromagnetic field strength, nondestructive planarization and regularization of the frozen tissue is induced, allowing the longitudinal tissue sectioning that favors subsequent molecular profiling by MALDI-MSI. As a proof of concept, flowers, leaves and roots with irregular morphology from six plant species are chosen to evaluate the performance of EMFAFTP for MALDI-MSI of secondary metabolites, amino acids, lipids, and proteins among others in the plant samples. The significantly enhanced MALDI-MSI capabilities of these endogenous molecules demonstrate the robustness of EMFAFTP and suggest it has the potential to become a standard technique for advancing MALDI-MSI into a new era of plant spatial omics.

Significant Enhancement of Thermoelectric Performance in Bi0.5 Sb1.5 Te3 Thin Film via Ferroelectric Polarization Engineering.

The Bi0.5 Sb1.5 Te3 (BST) thin film shows great promise in harvesting low-grade heat energy due to its excellent thermoelectric performance at room temperature. In order to further enhance its thermoelectric performance, specifically the power factor and output power, new approaches are highly desirable beyond the common "composition-structure-performance" paradigm. This study introduces ferroelectric polarization engineering as a novel strategy to achieve these goals. A Pb(Zr0.52 Ti0.48 )O3 /Bi0.5 Sb1.5 Te3 (PZT/BST) hybrid film is fabricated via magnetron sputtering. Density functional theory calculations demonstrate PZT polarization's influence on charge redistribution and interlayer charge transfer at the PZT/BST interface, facilitating adjustable carrier transport behavior and power factor of the BST film. As a result, a 26.7% enhancement of the power factor, from unpolarized 12.0 to 15.2 µW cm-1 K-2 , is reached by 2 kV out-of-plane downward polarization of PZT. Furthermore, a five-leg generator constructed using this PZT/BST hybrid film exhibits a maximum output power density of 13.06 W m-2 at ΔT = 39 K, which is 20.8% higher than that of the unpolarized one (10.81 W m-2 ). The research presents a new approach to enhance thermoelectric thin films' power factor and output performance by introducing ferroelectric polarization engineering.

Tissue-specific toxic effects of nano-copper on zebrafish.

Understanding the behavior and potential toxicity of copper nanoparticles (nano-Cu) in the aquatic environment is a primary way to assess their environmental risks. In this study, RNA-seq was performed on three different tissues (gills, intestines, and muscles) of zebrafish exposed to nano-Cu, to explore the potential toxic mechanism of nano-Cu on zebrafish. The results indicated that the toxic mechanism of nano-Cu on zebrafish was tissue-specific. Nano-Cu enables the CB1 receptor of the presynaptic membrane of gill cells to affect short-term synaptic plasticity or long-term synaptic changes (ECB-LTD) through DSI and DSE, causing dysfunction of intercellular signal transmission. Imbalance of de novo synthesis of UMP in intestinal cells and its transformation to UDP, UTP, uridine, and uracil, resulted in many functions involved in the pyrimidine metabolic pathway being blocked. Meanwhile, the toxicity of nano-Cu caused abnormal expression of RAD51 gene in muscle cells, which affects the repair of damaged DNA through Fanconi anemia and homologous recombination pathway, thus causing cell cycle disorder. These results provide insights for us to better understand the differences in toxicity of nano-Cu on zebrafish tissues and are helpful for a comprehensive assessment of nano-Cu's effects on aquatic organisms.

2,5-Dihydroxyterephthalic Acid: A Matrix for Improved Detection and Imaging of Amino Acids.

Amino acids (AAs), which are low-molecular-weight (low-MW) metabolites, serve as essential building blocks not only for protein synthesis but also for maintaining the nitrogen balance in living systems. In situ detection and imaging of AAs are crucial for understanding more complex biological processes. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a label-free mass spectrometric imaging technique that enables the simultaneous detection and imaging of the spatial distribution and relative abundance of different endogenous/exogenous compounds in biological samples. The excellent efficiency of MALDI-MSI is attributed to the choice of the MALDI matrix. However, to the best of our knowledge, no matrix has been specifically developed for AAs. Herein, we report a MALDI matrix, 2,5-dihydroxyterephthalic acid (DHT), which can improve the detection and imaging of AAs in biological samples by MALDI-MS. Our results indicated that DHT exhibited strong ultraviolet-visible (UV-vis) absorption, uniform matrix deposition, and high vacuum stability. Moreover, the matrix-related ion signals produced from DHT were reduced by 50 and 71.8% at m/z < 500 compared to the commonly used matrices of 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA), respectively, in their respective organic solvents. In terms of quantitative performance, arginine, glutamic acid, glutamine, and proline can be detected with limits of detection of 6, 4, 6, and 4 ng/mL, respectively, using the DHT as the matrix. Using DHT as the matrix, all 20 protein AAs were successfully detected in human serum by MALDI-MS, whereas only 7 and 10 AAs were detected when DHB and CHCA matrices were used, respectively. Furthermore, 20 protein AAs and taurine were successfully detected and imaged in a section of edible Crassostrea gigas (oyster) tissue for the first time. Our study demonstrates that using DHT as a matrix can improve the detection and imaging of AAs in biological samples by MALDI-MS.

High-throughput MALDI-MSI metabolite analysis of plant tissue microarrays.

A novel metabolomics analysis technique, termed matrix-assisted laser desorption/ionization mass spectrometry imaging-based plant tissue microarray (MALDI-MSI-PTMA), was successfully developed for high-throughput metabolite detection and imaging from plant tissues. This technique completely overcomes the disadvantage that metabolites cannot be accessible on an intact plant tissue due to the limitations of the special structures of plant cells (e.g. epicuticular wax, cuticle and cell wall) through homogenization of plant tissues, preparation of PTMA moulds and matrix spraying of PTMA sections. Our study shows several properties of MALDI-MSI-PTMA, including no need of sample separation and enrichment, high-throughput metabolite detection and imaging (>1000 samples per day), high-stability mass spectrometry data acquisition and imaging reconstruction and high reproducibility of data. This novel technique was successfully used to quickly evaluate the effects of two plant growth regulator treatments (i.e. 6-benzylaminopurine and N-phenyl-N'-1,2,3-thiadiazol-5-ylurea) on endogenous metabolite expression in plant tissue culture specimens of Dracocephalum rupestre Hance (D. rupestre). Intra-day and inter-day evaluations indicated that the metabolite data detected on PTMA sections had good reproducibility and stability. A total of 312 metabolite ion signals in leaves tissues of D. rupestre were detected, of which 228 metabolite ion signals were identified, they were composed of 122 primary metabolites, 90 secondary metabolites and 16 identified metabolites of unknown classification. The results demonstrated the advantages of MALDI-MSI-PTMA technique for enhancing the overall detection ability of metabolites in plant tissues, indicating that MALDI-MSI-PTMA has the potential to become a powerful routine practice for high-throughput metabolite study in plant science.

A concentration-descending washing strategy with methanol for the enhancement of protein imaging in biological tissues by MALDI-MS.

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a powerful approach that has been widely used for in situ detection of various endogenous compounds in tissues. However, there are still challenges with in situ analysis of proteins using MALDI-MSI due to the ion suppression effects of small molecules in tissue sections. Therefore, tissue-washing steps are crucial for protein MALDI tissue imaging to remove these interfering molecules. Here, we successfully developed a new method named the concentration-descending washing strategy (CDWS) with methanol (MeOH), i.e., washing of biological tissue with 100%, 95%, and 70% MeOH solutions, for the enhancement of endogenous in situ protein detection and imaging in tissues using MALDI-MS. The method of MeOH-based CDWS (MeOH-CDWS) led to the successful in situ detection of 272 ± 3, 185 ± 4, and 134 ± 2 protein ion signals from rat liver, rat brain, and germinating Chinese-yew seed tissue sections, respectively. By comparison, 161 ± 2, 121 ± 1, and 114 ± 2 protein ions were detected by three commonly used methods, i.e., Carnoy's wash, ethanol (EtOH)-based CAWS (i.e., concentration-ascending washing strategy, 70% EtOH followed by 90% EtOH/9% AcOH), and isopropanol (iPrOH)-based CAWS (70% iPrOH followed by 95% iPrOH), respectively, in rat liver tissue sections, indicating that 68.9 ± 3.1%, 124.8 ± 3.3%, and 138.6 ± 4.4% more protein ion signals could be detected by the use of MeOH-CDWS than the three abovementioned washing strategies. Our results show that the use of MeOH-CDWS improves the performance of MALDI-MSI for in situ protein detection such as the number and intensity of proteins. The use of MeOH-CDWS improves the fixation of proteins and thus reduces the loss of proteins, which significantly reduces protein delocalization in tissue and enhances the performance of MALDI tissue imaging of protein. Thus, the use of MeOH-CDWS improves the quality of protein images in tissue sections through MALDI-MSI and has the potential to be used as standard practice for MALDI tissue imaging of proteins.

A Caffeic Acid Matrix Improves In Situ Detection and Imaging of Proteins with High Molecular Weight Close to 200,000 Da in Tissues by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging.

To our knowledge, this was the first study in which caffeic acid (CA) was successfully evaluated as a matrix to enhance the in situ detection and imaging of endogenous proteins in three biological tissue sections (i.e., a rat brain and Capparis masaikai and germinating soybean seeds) by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Our results show several properties of CA, including strong ultraviolet absorption, a super-wide MS detection mass range close to 200,000 Da, micrometer-sized matrix crystals, uniform matrix deposition, and high ionization efficiency. More high-molecular-weight (HMW) protein ion signals (m/z > 30,000) could be clearly detected in biological tissues with the use of CA, compared to two commonly used MALDI matrices, i.e., sinapinic acid (SA) and ferulic acid (FA). Notably, CA shows excellent performance for HMW protein in situ detection from biological tissues in the mass range m/z > 80,000, compared to the use of SA and FA. Furthermore, the use of a CA matrix also significantly enhanced the imaging of proteins on the surface of selected biological tissue sections. Three HMW protein ion signals (m/z 50,419, m/z 65,874, and m/z 191,872) from a rat brain, two sweet proteins (mabinlin-2 and mabinlin-4) from a Capparis masaikai seed, and three HMW protein ion signals (m/z 94,838, m/z 134,204, and m/z 198,738) from a germinating soybean seed were successfully imaged for the first time. Our study proves that CA has the potential to become a standard organic acid matrix for enhanced tissue imaging of HMW proteins by MALDI-MSI in both animal and plant tissues.

An Onsite Calibration Method for MEMS-IMU in Building Mapping Fields.

Light detection and ranging (LiDAR) is one of the popular technologies to acquire critical information for building information modelling. To allow an automatic acquirement of building information, the first and most important step of LiDAR technology is to accurately determine the important gesture information that micro electromechanical (MEMS) based inertial measurement unit (IMU) sensors can provide from the moving robot. However, during the practical building mapping, serious errors may happen due to the inappropriate installation of a MEMS-IMU. Through this study, we analyzed the different systematic errors, such as biases, scale errors, and axial installation deviation, that happened during the building mapping, based on a robot equipped with MEMS-IMU. Based on this, an error calibration model was developed. The problems of the deviation between the calibrated and horizontal planes were solved by a new sampling method. For this method, the calibrated plane was rotated twice; the gravity acceleration of the six sides of the MEMS-IMU was also calibrated by the practical values, and the whole calibration process was completed after solving developed model based on the least-squares method. Finally, the building mapping was then calibrated based on the error calibration model, and also the Gmapping algorithm. It was indicated from the experiments that the proposed model is useful for the error calibration, which can increase the prediction accuracy of yaw by 1-2° based on MEMS-IMU; the mapping results are more accurate when compared to the previous methods. The research outcomes can provide a practical basis for the construction of the building information modelling model.

Toxicity and mechanisms of action of titanium dioxide nanoparticles in living organisms.

Titanium dioxide nanoparticles (TiO2 NPs) are one of the most widely used nanomaterials in the consumer products, agriculture, and energy sectors. Their large demand and widespread applications will inevitably cause damage to organisms and ecosystems. A better understanding of TiO2 NP toxicity in living organisms may promote risk assessment and safe use practices of these nanomaterials. This review summarizes the toxic effects of TiO2 NPs on multiple taxa of microorganisms, algae, plants, invertebrates, and vertebrates. The mechanism of TiO2 NP toxicity to organisms can be outlined in three aspects: The Reactive Oxygen Species (ROS) produced by TiO2 NPs following the induction of electron-hole pairs; cell wall damage and lipid peroxidation of the cell membrane caused by NP-cell attachment by electrostatic force owing to the large surface area of TiO2 NPs; and TiO2 NP attachment to intracellular organelles and biological macromolecules following damage to the cell membranes.

Effects of Pressure on the Microstructure and Simultaneous Optimization of the Electrical and Thermal Transport Properties of Yb0.5Ba7.5Ga16Ge30.

The thermoelectric (TE) properties of n-type polycrystalline Yb0.5Ba7.5Ga16Ge30 bulks can be optimized by high-pressure and high-temperature (HPHT) sintering. After HPHT sintering, abundant nanograins are randomly distributed in the sample. Grains are refined by HPHT, with the grains being smaller with higher pressure. In comparison with the arc-melted sample, the samples obtained by quenching under high pressure possess a great number of nanograins and lattice structural disorders. Lower thermal conductivity is benefited by our deliberately engineered microstructures via HPHT, and the minimum thermal conductivity is 0.86 W m-1 K-1 at 773 K. The thermal conductivity and electrical properties are optimized simultaneously by raising the reactive sintering pressure. In comparison with the arc-melted sample (0.56), a maximum zT value of 1.13 at 773 K is obtained for the Yb0.5Ba7.5Ga16Ge30 sample fabricated at 5 GPa. This demonstrates that HPHT provides an effective strategy to improve TE performance through simultaneously enhancing electrical and thermal transport properties and should be applicable to other thermoelectric materials.

Molecular Toxicity of Metal Oxide Nanoparticles in Danio rerio.

Metal oxide nanoparticles can exert adverse effects on humans and aquatic organisms; however, their toxic mechanisms are still unclear. We investigated the toxic effects and mechanisms of copper oxide, zinc oxide, and nickel oxide nanoparticles in Danio rerio using microarray analysis and the comet assay. Copper oxide nanoparticles were more lethal than the other metal oxide nanoparticles. Gene ontology analysis of genes that were differentially expressed following exposure to all three metal oxide nanoparticles showed that the nanoparticles mainly affected nucleic acid metabolism in the nucleus via alterations in nucleic acid binding. KEGG analysis classified the differentially expressed genes to the genotoxicity-related pathways "cell cycle", "Fanconi anemia", "DNA replication", and "homologous recombination". The toxicity of metal oxide nanoparticles may be related to impairments in DNA synthesis and repair, as well as to increased production of reactive oxygen species.

High-Pressure and High-Temperature Synthesis and Pressure-Induced Simultaneous Optimization of the Electrical and Thermal Transport Properties of Nonstoichiometric TiO1.80.

We developed suitable high-pressure and high-temperature (HPHT) conditions for improvement of the thermoelectric properties of nonstoichiometric TiO1.80. X-ray diffraction, scanning transmission microscopy, transmission electron microscopy, and ultraviolet spectral measurements demonstrate that the crystal structures and microstructures are strongly modulated by our HPHT. The electrical properties and thermal conductivity are improved simultaneously by raising the reactive sintering pressure. The band gap was narrowed, contributing to the increase of the electrical properties with the pressure. In addition, relatively low thermal conductivities were obtained here as a result of a full spectrum of phonon scattering, benefiting from our deliberately engineered microstructures via HPHT. As a consequence, a high dimensionless figure of merit (zT) of 0.36 was obtained at 700 °C in the sample fabricated at 5 GPa. As far as we know, this is higher than all of the results of nonstoichiometric titanium oxide by other means and an enhancement of 57% of the best ever result. HPHT offers us a promising alternative for optimization of the thermoelectric properties, and it is worthwhile to popularize it.

Expression and role of cystatin C in hyperthermia-induced brain injury in rats.

Cystatin C, the full name of cystatin C, is one of the most potent cathepsin inhibitors currently known, which can strongly inhibit cathepsin in lysosomes and regulate the level of intracellular proteolysis. Cystatin C plays a very broad role in the body. High temperature-induced brain injury leads to very serious damage to brain tissue, such as cell inactivation, brain tissue edema, etc. At this time, cystatin C can play a crucial role. Based on the research on the expression and role of cystatin C in high temperature-induced brain injury in rats, this paper draws the following conclusions: high temperature can cause very serious damage to the brain tissue of rats, which can seriously lead to death. Cystatin C has a protective effect on brain cells and cerebral nerves. When the brain is damaged by high temperature, cystatin C can relieve the damage of high temperature to the brain and protect brain tissue. In this paper, a detection method for cystatin C with more outstanding performance is proposed, and compared with the traditional detection method, the detection method in this paper is verified to have more accurate accuracy and excellent stability through comparative experiments. Compared with traditional detection methods, it is more worthwhile to use and is a better detection method.

A Kernel-Based Multi-Featured Rock Modeling and Detection Framework for a Mars Rover.

This article presents two kernel-based rock detection methods for a Mars rover. Rock detection on planetary surfaces is particularly pivotal for planetary vehicles regarding navigation and obstacle avoidance. However, the diverse morphologies of Martian rocks, the sparsity of pixel-wise features, and engineering constraints are great challenges to current pixel-wise object detection methods, resulting in inaccurate and delayed object location and recognition. We therefore propose a region-wise rock detection framework and design two detection algorithms, kernel principle component analysis (KPCA)-based rock detection (KPRD) and kernel low-rank representation (KLRR)-based rock detection (KLRD), using hypotheses of feature and sub-spatial separability. KPRD is based on KPCA and is expert in real-time detection yet with less accurate performance. KLRD is based on KPRD with KLRR which can generate more precise rock detection results with less delay. To validate the efficiency of the proposed methods, we build a small-scale Martian rock dataset, MarsData, containing various rocks. Preliminary experimental results show that our methods are efficient in dealing with complex images containing rocks, shadows, and gravel. The code and data are available at: https://github.com/CVIR-Lab/MarsData.

Evaluation of Satisfaction with the Built Environment of University Buildings under the Epidemic and Its Impact on Student Anxiety.

Anxiety on college campuses has increased due to the COVID-19 epidemic's profound effects on society. Much research has been conducted on how the built environment influences mental health; however, little has been undertaken on how it affects student mental health in the context of the epidemic from the architectural scale perspective of academic buildings. Based on online survey data, this study develops multiple linear regression and binary logistic regression models to investigate students' satisfaction ratings of the academic buildings' physical environments during the epidemic and how these satisfaction ratings affect students' anxiety tendencies. According to the study's findings regarding the natural exposure perspective, students who perceived the academic building's poor semi-open space view (p = 0.004, OR = 3.22) as unsatisfactory factors were more likely to show anxiety tendencies. In terms of the physical conditions, students who were dissatisfied with the noise level in the classroom (p = 0.038, OR = 0.616) and the summer heat in semi-open spaces (p = 0.031, OR = 2.38) were more likely to exhibit anxiety tendencies. Additionally, even after controlling for confusing distractions, the general satisfaction rating of the academic building's physical environments (p = 0.047, OR = 0.572) was still able to significantly and negatively affect students' anxiety tendencies. The study's findings can be used in the architectural and environmental planning of academic buildings focusing on mental health.

Comprehensive clinical evaluation of moxifloxacin: A retrospective study.

The objective was to provide a basis for the rational clinical application of moxifloxacin through its comprehensive clinical evaluation, and to serve as a reference for the clinical comprehensive evaluation of relevant drugs in the future. We obtained data from 91 community-acquired pneumonia patients admitted to Weifang people's hospital from April 2020 to November 2021, including 46 in the evaluation group and 45 in the control group. Based on the requirements of the "Guidelines for the Management of Comprehensive Clinical Evaluation of Drugs" (for trial implementation), systematic evaluations are conducted in terms of drug safety, effectiveness, economy, innovation, suitability, and accessibility. The incidence of adverse drug reactions was low, drug quality, safety and stable efficacy; treatment efficiency was 91.3% and 93.3%, respectively (P > .05); the average total cost of the evaluation group was 9765.28RMB and 10250.69RMB, respectively; efficient cost-effectiveness ratio was 104.67 and 112.52 and cost-effectiveness ratio was 242.71. The economy of the evaluation group had a low price and was highly available.

High Thermoelectric Performance in Cu-Doped Bi2Te2.7Se0.33 Due to Cl Doping and Multiscale AgBiSe2.

The thermoelectric performance of n-type Bi2Te3 needs further enhancement to match that of its p-type Bi2Te3 counterpart and should be considered for competitive applications. Combining Cu/Cl and multiscale additives (AgBiSe2) presents a suitable route for such enhancement. This is evidence of the enhanced thermoelectric performance of Bi1.995Cu0.005Te2.69Se0.33Cl0.03. Moreover, by incorporating 0.65 wt % AgBiSe2 (ABS) into Bi1.995Cu0.005Te2.69Se0.33Cl0.03, we further reduce its lattice thermal conductivity to ∼0.28 W m-1 K-1 at 353 K owing to the extra phonon scattering of multiscale ABS. Additionally, the Seebeck coefficient enhances (-183.89 µV K-1 at 353 K) owing to the matrix's reduced carrier concentration caused by ABS. As a result, we achieve a high ZT of ∼1.25 (at 353 K) and a high ZTave of ∼1.12 at 300-433 K for Bi1.995Cu0.005Te2.69Se0.33Cl0.03 + 0.65 wt % ABS. This work provides a promising strategy for enhancing the thermoelectric performance of n-type Bi2Te3 through Cu/Cl doping and ABS incorporation.

Polyacrylamide gel as a new embedding medium for the enhancement of metabolite MALDI imaging.

In this study, polyacrylamide gel (PAAG) was successfully used as a new embedding medium to provide the more effective maintenance of biological tissues during the sectioning process, enhancing the tissue imaging of metabolites via matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Herein, PAAG, agarose, gelatin, optimal cutting temperature compound (OCT), and ice media were used to embed rat liver and Atlantic salmon (Salmo salar) eyeball samples. These embedded tissues were then sectioned into thin slices and thaw-mounted on conductive microscope glass slides for MALDI-MSI detection to evaluate the embedding effects. The results showed that PAAG embedding has characteristics superior to those of commonly-used embedding media (e.g., agarose, gelatin, OCT, and ice) with the advantages of one-step operation without heating, a better performance of morphology maintenance, the absence of PAAG polymer-ion-related interference below m/z 2000, and the more efficient in situ ionization of metabolites, providing a significant enhancement of both the numbers and intensities of the metabolite ion signals. Our study demonstrates the potential of PAAG embedding as a standard practice for metabolite MALDI tissue imaging, which will lead to an expanded application scope of MALDI-MSI.