A photochemically covalent lock stabilizes aptamer conformation and strengthens its performance for biomedicine.

Aptamers' vast conformation ensemble consisting of interconverting substates severely impairs their performance and applications in biomedicine. Therefore, developing new chemistries stabilizing aptamer conformation and exploring the conformation-performance relationship are highly desired. Herein, we developed an 8-methoxypsoralen-based photochemically covalent lock to stabilize aptamer conformation via crosslinking the inter-stranded thymine nucleotides at TpA sites. Systematical studies and molecular dynamics simulations were performed to explore the conformation-performance relationship of aptamers, revealing that conformation-stabilized aptamers displayed better ability to bind targets, adapt to physiological environment, resist macrophage uptake, prolong circulation half-life, accumulate in and penetrate into tumor than their counterparts. As expected, conformation-stabilized aptamers efficiently improved the therapeutic efficacy of aptamer-drug conjugation on tumor-bearing mice. Collectively, our study has developed a general, simple and economic strategy to stabilize aptamer conformation and shed light on the conformation-performance relationship of aptamers, laying a basis for promoting their basic researches and applications in biomedicine.

TSD-Truncated Structurally Aware Distance for Small Pest Object Detection.

As deep learning has been successfully applied in various domains, it has recently received considerable research attention for decades, making it possible to efficiently and intelligently detect crop pests. Nevertheless, the detection of pest objects is still challenging due to the lack of discriminative features and pests' aggregation behavior. Recently, intersection over union (IoU)-based object detection has attracted much attention and become the most widely used metric. However, it is sensitive to small-object localization bias; furthermore, IoU-based loss only works when ground truths and predicted bounding boxes are intersected, and it lacks an awareness of different geometrical structures. Therefore, we propose a simple and effective metric and a loss function based on this new metric, truncated structurally aware distance (TSD). Firstly, the distance between two bounding boxes is defined as the standardized Chebyshev distance. We also propose a new regression loss function, truncated structurally aware distance loss, which consider the different geometrical structure relationships between two bounding boxes and whose truncated function is designed to impose different penalties. To further test the effectiveness of our method, we apply it on the Pest24 small-object pest dataset, and the results show that the mAP is 5.0% higher than other detection methods.

Design of carboxymethyl cellulose/alginate aerogels with anti-fouling and light-driven self-cleaning for enhanced oily wastewater remediation.

With the increase of oily wastewater discharge and the growing demand for clean water supply, high throughput green materials for oil-water separation with anti-pollution and self-cleaning ability are urgently needed. Herein, the polysaccharide-based composite aerogels of CMC/SA@TiO2-MWCNTs (CSTM) with fast photo-driven self-cleaning ability have been prepared by a simple freeze-drying and ionic cross-linking strategy. The introduction of TiO2 /MWCNTs nanocomposites effectively improves the underwater oleophobic and mechanical properties of polysaccharide aerogels and enables their photo-driven self-cleaning ability for efficient oil-water separation and purification of complex oily wastewater. For immiscible oil-water mixtures, a high separation flux of about 7650 L m-2 h-1 and a separation efficiency of up to 99.9 % was obtained. For surfactant-stabilized oil-in-water emulsion, a flux of 3952 L m-2 h-1 was achieved with a separation efficiency of up to 99.3 %. More importantly, the excellent photoluminescent self-cleaning ability and low oil adhesion contribute to the high contamination resistance, excellent reusability, and robust durability of CSTM aerogel. With the advantages of simple preparation, remarkable performance, and recyclability, this aerogel is expected to provide a green, economical, and scalable solution for the purification of oily wastewater.

Wide-humidity, anti-freezing and stretchable multifunctional conductive carboxymethyl cellulose-based hydrogels for flexible wearable strain sensors and arrays.

Hydrogels play an important role in the design and fabrication of wearable sensors with outstanding flexibility, high sensitivity and versatility. Since hydrogels lose and absorb water during changes in humidity and temperature, it is critical and challenging to obtain hydrogels that function properly under different environmental conditions. Herein, a dual network hydrogel based on tannic acid (TA) reinforced polyacrylamide (PAM) and sodium carboxymethylcellulose (CMC) was constructed, while the introduction of the green solvents Solketal and LiCl endowed the hydrogel with greater possibilities for further modification to improve the water content and consistency of the mechanical properties over 30-90 % RH. This composite hydrogel (PTSL) has long-term stability, excellent mechanical strength, and freezing resistance. As strain sensors, they are linear over the entire strain range (R2 = 0.994) and have a high sensitivity (GF = 2.52 over 0-680 % strain range). Furthermore, the hydrogel's exceptional electrical conductivity and freezing resistance are a result of the synergistic effect of Solketal and LiCl, which intensifies the contact between the water molecules and the colloidal phase. This research could address the suitability of hydrogels over a wide range of humidity and temperature, suggesting great applications for smart flexible wearable electronics in harsh environmental conditions.

Genome-wide association studies reveal novel QTLs for agronomic traits in soybean.

Introduction: Soybean, as a globally significant crop, has garnered substantial attention due to its agricultural importance. The utilization of molecular approaches to enhance grain yield in soybean has gained popularity. Methods: In this study, we conducted a genome-wide association study (GWAS) using 156 Chinese soybean accessions over a two-year period. We employed the general linear model (GLM) and the mixed linear model (MLM) to analyze three agronomic traits: pod number, grain number, and grain weight. Results: Our findings revealed significant associations between qgPNpP-98, qgGNpP-89 and qgHGW-85 QTLs and pod number, grain number, and grain weight, respectively. These QTLs were identified on chromosome 16, a region spanning 413171bp exhibited associations with all three traits. Discussion: These QTL markers identified in this study hold potential for improving yield and agronomic traits through marker-assisted selection and genomic selection in breeding programs.

Structural analysis of low molecular weight heparin by ultraperformance size exclusion chromatography/time of flight mass spectrometry and capillary zone electrophoresis.

Although low molecular weight heparins (LMWHs) have been used as anticoagulant agents for over 2 decades, their structures have not been fully characterized. In this work, we propose a new strategy for the comprehensive structural analysis of LMWHs based on the combination of ultraperformance size exclusion chromatography/electrospray quadruple time-of-flight-mass spectrometry (UPSEC/Q-TOF-MS) and capillary zone electrophoresis (CZE). More than 70 components, including oligosaccharides with special structures such as 1,6-anhydro rings, saturated uronic acid at the nonreducing end and odd-numbered saccharides units were identified with UPSEC/Q-TOF-MS. Furthermore, a more detailed compositional analysis was accomplished by CZE analysis. PEG10000 and MgCl(2) were added to the background electrolyte to separate those saccharides with the nearly same charge-to-mass ratio. Baseline separation and quantification of all the building blocks of the most complex LMWH, namely, enoxaparin, which include 10 disaccharides, 1 trisaccharide, 2 tetrasaccharides, and, of particular importance, 4 1,6-anhyro derivatives, was achieved using CZE for the first time. Additionally, the peaks of oligosaccharides, in the absence of commercially available standards, were assigned on the basis of the linear correlation between the electrophoretic mobilities of oligosaccharides and their charge-to-mass ratios. These two approaches are simple and robust for structural analysis of LMWHs.

Establishment of a novel system for photothermal removal of ampicillin under near-infrared irradiation: Persulfate activation, mechanism, pathways and bio-toxicology.

One of the most effective ways to address the problems of low solar spectrum utilization in photocatalysis and the high cost of persulfate activation technology is to create a cost-effective synergistic photothermal persulfate system. In this work, a brand-new composite catalyst called ZnFe2O4/Fe3O4@MWCNTs (ZFC) was developed to activate PDS (K2S2O8) from the aforementioned basis. ZFC's surface temperature could unbelievably reach 120.6 °C in 150 s together with the degrading synergistic system solution temperature could reach 48 °C under near-infrared light (NIR) in 30 min, thus accelerating the ZFC/PDS decolorization rate for reactive blue KN-R (150 mg/L) to 95% in 60 min. Furthermore, the ZFC's ferromagnetism bore it with good cycling performance, allowing it to maintain an 85% decolorization rate even after 5 cycles with OH·, SO4-·, 1O2, and O2-· dominating the degrading process. In the meantime, the DFT calculations of the kinetic constants for the entire process of S2O82- adsorption on Fe3O4 in dye degradation solution were in agreement with the outcomes of the experimental pseudo-first-order kinetic fitting. By analyzing the particular degradation route of ampicillin (50 mg/L) and the possible environmental impact of the intermediate using LC-MS and the toxicological analysis software (T.E.S.T.), respectively, it was shown that this system might function as an environmentally friendly method for removing antibiotics. This work may provide some productive research lines for the creation of a photothermal persulfate synergistic system and suggest fresh approaches to water treatment technology.

Supported photocatalyst for Cr (VI) conversion and removal of organic pollutants.

The photocatalytic property of available semiconductor catalysts still suffers from some urgent problems, such as the high excitation energy, easy agglomeration of powders, or weak recycling property. Therefore, developing novel visible light-supported catalysts and catalyst loading have aroused great attention recently. In this work, a novel Ag3PO4/BiVO4/MWCNTs@Cotton functional fabric was prepared by introducing Ag3PO4 as a plasma resonance photocatalyst and MWCNTs with cotton as composite substrates. Not only did the introduction of Ag3PO4 and MWCNTs effectively strengthen the application ability of BiVO4, but also inhibited the recombination of carriers, and promoted the transport of carriers according to spectroscopic and electrochemical tests. Degradation tests remained that Ag3PO4/BiVO4/MWCNTs @cotton retained the high photocatalytic efficiency of the powder catalyst, along with the degradation degree of active blue KN-R (50mg/L) as well as Cr (VI) (20mg/L) could reach more than 90% within 120 min. What's more, the functional fabric has gained excellent performance in degrading pollutants for 5 cycles. Meanwhile, the prepared BiVO4 is consistent with the band structure and electron density calculated theoretically by the GGA-PBE function. Free radical trapping and scavenging experiments exhibited that functional fabrics could produce active substances such as h+,·O2-, and·OH, among which the first two are the main active substances in the reaction. To sum up, this study is an effective attempt based on the existing problems of photocatalysts together with providing some study directions for the development of photocatalytic technology in the future.

MOFFeCo/B-CN composites achieve efficient degradation of antibiotics in a non-homogeneous concurrent photocatalytic-persulfate activation system.

We synthesized an MFeCoB0.4CNx% (MOF-Fe/Co nanosheets/boron-doped g-C3N4) composite catalyst for enhancing the concurrent photocatalytic-persulfate activation (CPPA) system and achieved efficient degradation of antibiotics. The role of MOF-Fe/Co is to activate persulfate, while boron-doped g-C3N4 can generate photogenerated electrons for the reduction of Co3+/Fe3+ to enhance the regeneration of the active center. The rate constant for Tetracycline degradation by the CPPA system was 4.74 and 7.54 times higher than the photocatalytic and persulfate-activated systems, respectively. This composite was shown to be practical and economically viable for antibiotic degradation. The degradation behavior was explored based on experiments, and molecular orbitals and Fukui functions were obtained by density functional theory calculations. Mechanisms were investigated using reactive oxygen species trapping studies and electron spin resonance, and the process was explained in terms of the charge population and electron density difference of MOF-Fe/Co nanosheets. The CPPA system is an ecologically benign technology for removing antibiotic-related risks to the environment and human health.

Salt altered rhizosphere fungal community and induced soybean recruit specific species to ameliorate salt stress.

Different crop genotypes showed different adaptability to salt stress, which is partly attributable to the microorganisms in the rhizosphere. Yet, knowledge about how fungal communities of different genotypes in soybean respond to salt stress is limited. Here, qPCR and ITS sequencing were used to assess the response of rhizobial fungal communities of resistant and susceptible soybean to salt stress. Moreover, we isolated two fungal species recruited by resistant soybeans for validation. The assembly of fungal community structure might be strongly linked to alterations in fungal abundance and soil physicochemical properties. Salt stress derived structural differences in fungal communities of resistant and susceptible genotypes. The salt-resistant genotype appeared to recruit some fungal taxa to the rhizosphere to help mitigating salt stress. An increase of fungal taxa with predicted saprotrophic lifestyles might help promoting plant growth by increasing nutrient availability to the plants. Compared with the susceptible genotypes, the resistant genotypes had more stronger network structure of fungi. Lastly, we verified that recruited fungi, such as Penicillium and Aspergillus, can soybean adapt to salt stress. This study provided a promising approach for rhizospheric fungal community to enhance salt tolerance of soybean from the perspective of microbiology and ecology.

Effects of salt stress on soil enzyme activities and rhizosphere microbial structure in salt-tolerant and -sensitive soybean.

Salt is recognized as one of the most major factors that limits soybean yield in acidic soils. Soil enzyme activity and bacterial community have a critical function in improving the tolerance to soybean. Our aim was to assess the activities of soil enzyme, the structure of bacteria and their potential functions for salt resistance between Salt-tolerant (Salt-T) and -sensitive (Salt-S) soybean genotypes when subject to salt stress. Plant biomass, soil physicochemical properties, soil catalase, urease, sucrase, amylase, and acid phosphatase activities, and rhizosphere microbial characteristics were investigated in Salt-T and Salt-S soybean genotypes under salt stress with a pot experiment. Salt stress significantly decreased the soil enzyme activities and changed the rhizosphere microbial structure in a genotype-dependent manner. In addition, 46 ASVs which were enriched in the Salt-T geotype under the salt stress, such as ASV19 (Alicyclobacillus), ASV132 (Tumebacillus), ASV1760 (Mycobacterium) and ASV1357 (Bacillus), which may enhance the tolerance to soybean under salt stress. Moreover, the network structure of Salt-T soybean was simplified by salt stress, which may result in soil bacterial communities being susceptible to external factors. Salt stress altered the strength of soil enzyme activities and the assembly of microbial structure in Salt-T and Salt-S soybean genotypes. Na+, NO3--N, NH4+-N and Olsen-P were the most important driving factors in the structure of bacterial community in both genotypes. Salt-T genotypes enriched several microorganisms that contributed to enhance salt tolerance in soybeans, such as Alicyclobacillus, Tumebacillus, and Bacillus. Nevertheless, the simplified network structure of salt-T genotype due to salt stress may render its bacterial community structure unstable and susceptible.

Facile fabrication of BiOIO3/MIL-88B heterostructured photocatalysts for removal of pollutants under visible light irradiation.

In this work, a Z-scheme heterojunction of BiOIO3/MIL-88B was constructed via two steps solvothermal method. Various characterization techniques showed that this Z-scheme heterojunction is an effective strategy to promote spatial charge separation, and the catalytic performance was evaluated by degrading simulated organic pollutants. Herein, the BiOIO3/MIL-88B composites exhibited an exceptional removal rate for Reactive Blue 19 and tetracycline hydrochloride (TC) under visible light irradiation, which was approximately 3.28 and 4.22 times higher than the pristine BiOIO3, respectively. Additionally, the analysis of photocatalysis mechanism showed that the active species O2- and OH could strongly affect the degradation of tetracycline hydrochloride (TC) in the studied system. Furthermore, the degradation process of TC was tracked and detected by identifying intermediates produced in the reaction system. It is anticipated that this research can deepen the understanding of BiOIO3/MIL-88B heterojunction structure to remove organic contaminants and provide a strategy for applying photocatalytic technology in the practical industry.

Construction of perylene diimide/CuS supramolecular heterojunction for the highly efficient visible light-driven environmental remediation.

Developing photocatalysts that are inexpensive and efficient in degrading pollutants are essential for environmental remediation. Herein, a novel system of perylene diimide (PDI)/CuS p-n heterojunction was synthesized by a two-step self-assembly strategy for removal of tetracycline in waste water. Results showed that PDI/CuS-10% exhibited highest photocatalytic behavior. The apparent rate constants for tetracycline (TC) degradation for the blend were 5.27 and 2.68 times higher than that of CuS or PDI, respectively. The enhancement of photocatalytic activity was mainly attributed to the π-π stacking and p-n junction, which can accelerate the separation of the photo-generated h+-e- pairs. Besides, the light absorption of PDI/CuS from 800 to 200 nm was significantly enhanced and the absorption edge even reached the near-infrared region, which also played an important role in providing desired photocatalytic properties. Surprisingly, PDI/CuS could maintain high catalytic activity even after 5 cycles under simulated conditions, indicating that the composite had high potential for practical applications. Owing to high efficiency, low cost and wide application range, the PDI/CuS nanocomposites are promising candidates for environmental remediation.

A quinoline-based fluorescent chemosensor for palladium ion (Pd2+)-selective detection in aqueous solution.

Quinoline-based fluorescent chemosensors have been extensively developed for various metal cations, but it was still rare for Pd2+-selective detection. In this work, a novel quinoline-benzimidazole conjugate containing one carboxylic acid group (QBM) was designed, and the QBM displayed highly selective fluorescence quenching response towards Pd2+ over other metal cations in aqueous solution. The fluorescence titration revealed a good linear relationship between the fluorescence intensity and the Pd2+ concentration in the range of 0.5-10 µmol L-1, with the detection limit of 0.26 µmol L-1 (S/N = 3). Fluorescence detection of Pd2+ in practical water sample was also successfully achieved.

Synthesis of Novel Ternary Photocatalyst Ag3PO4/Bi2WO6/Multi-Walled Carbon Nanotubes and Its Enhanced Visible-Light Photoactivity for Photodegradation of Norfloxacin.

Novel nanocomposites of Ag3PO4/Bi2WO6/MWCNTs were prepared via a facile hydrothermal method and in-situ precipitation without the addition of any spherical template. The composites exhibited excellent catalytic activity under visible-light irradiation. Compared with pure Ag3PO4, Bi2WO6, Bi2WO6/MWCNTs, and Ag3PO4/Bi2WO6, ternary Ag3PO4/Bi2WO6/MWCNTs nanocomposites showed the best photocatalytic performance due to the narrow band gap, large specific surface area, high charge separation efficiency, and strong light absorbance in the visible region. Degradation experiments involving norfloxacin (NOR) antibiotics under visible-light irradiation confirmed ideal photocatalytic activity of Ag3PO4/Bi2WO6/MWCNTs nanocomposites. Degradation products of NOR were identified via LC-MS/MS analysis, and a potential photodegradation mechanism of NOR was discussed; results indicated that these antibiotics could be degraded via three pathways. The piperazinyl ring was the most reactive site for hydroxyl radical attacks, followed by stepwise oxidation and further ring-opening. Overall, the composites appear to be promising materials for removing contaminants from water.

Development of a near-infrared ratiometric fluorescent probe for glutathione using an intramolecular charge transfer signaling mechanism and its bioimaging application in living cells.

A novel near-infrared (NIR) ratiometric fluorescent probe HBT-GSH derived from conjugated benzothiazole was developed for the selective detection of glutathione (GSH) over cysteine (Cys) and homocysteine (Hcy). The probe was sophisticatedly designed based on the GSH selectively induced enhancement of intramolecular charge transfer (ICT) fluorescence. It was synthesized by masking the active phenol group of 2,6-bis(2-vinylbenzothiazolyl)-4-fluorophenol through an acetyl group that acts both as a trigger of the ICT fluorescence and as a recognition moiety for GSH. On its own, the probe HBT-GSH exhibited strong blue fluorescence emission at 426 nm and weak NIR fluorescence emission at 665 nm in aqueous solution, whereas the NIR fluorescence was significantly enhanced and the short emission decreased upon the addition of GSH. Thus an NIR ratiometric fluorescent probe for GSH was developed based on the GSH-selective removal of the acetyl group, therefore switching on the ICT in HBT-GSH. The fluorescence intensity ratio (I665 nm/I426 nm) showed a linear relationship with a GSH concentration of 0-100 µM with a detection limit of 0.35 µM. Moreover, the fluorescent probe was successfully used for the ratiometric fluorescence bioimaging of GSH in living cells.

A selective fluorescent chemosensor for Cd2+ based on 8-hydroxylquinoline-benzothiazole conjugate and imaging application.

A 8-hydroxylquinoline-benzothiazole conjugate (HQ-BT) was facilely synthesized by two steps with >60% total reaction yield. The HQ-BT showed a weak fluorescence that could be strongly enhanced by coordination with various metal ions such as Al3+, Cd2+, Zn2+ in methanol containing 1% water. Interestingly, the selectivity toward Cd2+ was achieved by increasing water fraction to 30% aqueous methanol solution. Thus, the HQ-BT was developed as a new and selective fluorescent chemosensor for Cd2+ in aqueous solution with a broad pH region 4-12. A good linear relationship between the fluorescence intensity and the Cd2+ concentration was found in the range of 0-5 µM with a detection limit of 0.1 µM (S/N = 3). It was also succesfully used for fluorescence imaging of Cd2+ in living cells.

[Separation and quantitative analysis of the composition of low molecular weight sulfated polysaccharides by size exclusion chromatography].

As the composition of low molecular weight sulfated polysaccharides is very complex, the quantitative analysis of their compositions is very important for understanding their bioactivity and the purpose of the quality control. A method was developed for the separation and quantitative analysis of the composition of low molecular weight sulfated polysaccharides. The effects of the parameters, such as the mobile phase constitution including ionic strength and pH, column length and temperature, flow rate of the mobile phase on the separation were systematically investigated. The obtained optimal conditions were as follows: two TSK-GEL G2000 SWxl columns (300 mm x 7.8 mm) coupled together; mobile phase, 100 mmol/L Na2HPO4-NaH2PO4(pH 7.0); flow rate, 0.5 mL/min; column temperature, 35 degrees C; injection volume, 5 microL; sample concentration, 10 g/L. The method was validated in terms of its reproducibility and robustness. Under the optimized chromatographic separation conditions, each composition of the low molecular weight sulfated polysaccharide can be clearly separated, and their distribution ratios were quantitatively analyzed. The composition profilings of the samples from United States pharmacopoeia (USP), the two commercial available samples and two home-made samples were quantitatively compared. The method can be used for the quality control of the drugs based on low molecular weight sulfated polysaccharides.

[Determination of trace sulfate ion in liposome doxorubicin with capillary electrophoresis].

A capillary electrophoretic method for the determination of the trace sulfate ion in liposome doxorubicin has been developed with potassium nitrate as the background electrolyte. The components and pH of the buffer solution, the concentration of electroosmotic flow modifier and the separation voltage on the separation were studied in detail. The optimized electrophoretic conditions were as follows: capillary column diameter 50 microm, total length 60 cm and effective length 51.5 cm, 20 mmol/L potassium nitrate buffer solution (pH 7.0) containing 0.4 mmol/L cetyltrimethylammonium chloride (CTAC) as the electroosmotic flow modifier, an applied voltage of -15 kV (reversed polarity) and a detection wavelength of 202 nm. Under the optimized capillary electrophoresis separation conditions, sulfate ion and chloride ion in the liposome doxorubicin breaking emulsion were separated successfully within 3 min, and the relative standard deviations of migration time and peak area of sulfate ion were less than 0.01% and 1.0% respectively. The detection limit was 5 microg/L. This method has been proved to be simple, sensitive and accurate, and also has been applied to determine sulfate ion in liposome doxorubicin sample with satisfactory results.