Algorithm of spatial-temporal simulation for environment-strain interactions in strain-strain consortia based on resource competition mechanism.

Interaction simulation for co-culture systems is important for optimizing culture conditions and improving yields. For industrial production, the environment significantly affects the spatial-temporal microbial interactions. However, the current research on polymicrobial interactions mainly focuses on interaction patterns among strains, and neglects the environment influence. Based on the resource competition relationship between two strains, this research set up the modules of cellular physicochemical properties, nutrient uptake and metabolite release, cellular survival, cell swimming and substrate diffusion, and investigated the spatial-temporal strain-environment interactions through module coupling and data mining. Furthermore, in an Escherichia coli-Saccharomyces cerevisiae consortium, the total net reproduction rate decreased as glucose was consumed. E. coli gradually dominated favorable positions due to its higher glucose utilization capacity, reaching 100 % abundance with a competitive strength of 0.86 for glucose. Conversely, S. cerevisiae decreased to 0 % abundance with a competitive strength of 0.14. The simulation results of environment influence on strain competitiveness showed that inoculation ratio and dissolved oxygen strongly influenced strain competitiveness. Specifically, strain competitiveness increased with higher inoculation ratio, whereas E. coli competitiveness increased as dissolved oxygen increased, in contrast to S. cerevisiae. On the other hand, substrate diffusion condition, micronutrients and toxins had minimal influence on strain competitiveness. This method offers a straightforward procedure without featured downscaling and provides novel insights into polymicrobial interaction simulation.

Scaffold Hopping of Pristimerin Provides Derivatives Containing a Privileged Quinoxaline Substructure as Potent Autophagy Inducers in Breast Cancer Cells.

Pristimerin is a natural triterpenoid that has received much attention from medicinal chemists for its multiple biological activities. However, structural modifications of pristimerin, especially those aimed at discovering antitumor agents, are relatively limited. In this study, two series of pristimerin derivatives containing phenyloxazole and quinoxaline moieties, respectively, were designed via the scaffold hopping strategy. The target compounds were synthesized and analyzed for their cytotoxic activities in vitro using the MTT assay. The most potent cytotoxic compound (21o) significantly inhibited the proliferation of MCF-7 cells with an IC50 value of 2.0 µM, 1.5-fold more potent than pristimerin (IC50 = 3.0 µM). Compared with pristimerin, compound 21o displayed the greatest improvement in selectivity (25.7-fold) against the MCF-7 and MCF-10A cell lines. Transmission electron microscopy, monodansylcadaverine and DCFH-DA staining, Western blotting, and different inhibitor assays were performed to elucidate the mechanism of action of compound 21o. Compound 21o induced autophagy-mediated cell death in MCF-7 cells by activating the ROS/JNK signaling pathway. Therefore, incorporating a quinoxaline substructure into pristimerin could be advantageous for enhancing its cytotoxic activity. Compound 21o may serve as a lead compound for developing new therapies to treat breast cancer.

Novel insights into the biological state in algal-bacterial granular sludge granulation: Armor-like protection provided by the algal barrier.

Algal-bacterial granular sludge (ABGS) composed of microalgae and aerobic granular sludge, is a sustainable and promising technology for wastewater treatment. However, the formation mechanism of ABGS has not been clearly defined, and the direct formation of ABGS in saline wastewater has rarely been investigated. This study proposed novel insights into the granulation process of ABGS by assembling the algal barrier, which was successfully cultivated directly in saline wastewater. The results concluded that ABGS with the algal barrier maintained a higher biomass (MLSS of 7046 ± 61 mg/L), larger particle sizes (1.21 ± 0.06 mm), and better settleability (SVI30 of 46 ± 1 mL/g), enabling efficient pollutants removal. Soluble microbial products (SMP) were found to be closely related to the emergence of the algal barrier. In addition, under salinity stress, the high production of extracellular polymeric substances (EPS, 133.70 ± 1.40 mg/g VSS), specifically TB-EPS (90.29 ± 1.12 mg/g VSS), maintained a crucial role in the formation of ABGS. Further analysis indicated that biofilm producing bacteria Pseudofulvimonas and filamentous eukaryote Streptophyta were the key players in ABGS formation with the algal barrier. Furthermore, the enhancement of key genes and enzymes involved in nitrogen metabolism, TCA cycle, and polysaccharide metabolism suggested a more robust protective effect provided by the algal barrier. This study is expected to advance the application of simultaneous ABGS formation and pollutant removal in wastewater.

Liposome-embedded PtCu nanozymes for improved immunoassay of accurate myocardial infarction.

Herein, we developed a platinum-copper nano-enzyme-linked immunosorbent assay (NLISA) based split diagnostic platform for the ultrasensitive detection of cardiac troponin I (cTnI). The PtCu nanozyme synthesized by one-pot synthesis exhibited ultra-high peroxidase-like activity (35.17 U mg-1), which was about 4.5 times higher than that of the unmodified Pt nanozyme (8.83 U mg-1). Due to the efficient peroxidase-like activity of the copper-platinum complexed nanozyme, transduction and sequential amplification of cTnI biological signals were achieved in combination with a liposome-embedded amplification strategy. The encapsulation efficiency was calculated by introducing a liposomal bilayer model, which showed that the introduction of a single liposomal molecule could amplify the signal up to 870-fold, thus promising a high sensitivity test. Notably, the dynamic response of cTnI was in the range of 0.1-5000 pg mL-1 with an ultra-low detection limit (0.048 pg mL-1). The developed NLISA analysis system provides a new way to discover efficient and sensitive alternatives to ELISA kits, which can meet the practical needs of community healthcare testing conditions and rapid testing in hospitals.

Effects of carrier surface hydrophilic modification on sludge granulation: From sludge characteristics, extracellular polymeric substances, and microbial community.

Aerobic granular sludge (AGS) is a powerful biotechnological tool capable of treating multiple pollutants simultaneously. However, the granulation process and pollutant removal efficiency still need to be further improved. In this study, Fe2O3- and MnO2-surface-modified straw foam-based AGS (Fe2O3@SF-AGS and MnO2@SF-AGS), with an average particle size of 3 mm, were developed and evaluated. The results showed that surface modification reduced the hydrophobic groups of carriers, facilitating the attachment and proliferation of microorganisms. Notably, MnO2@SF-AGS showed excellent granulation performance, reaching a stable state about one week earlier than the unmodified SF-AGS. The polymeric substance content of MnO2@SF-AGS was found to be 1.28 times higher than that of the control group. Furthermore, the removal rates for NH4+-N, TN, and TP were enhanced by 27.28%, 12.8%, and 32.14%, respectively. The bacterial communities exhibited significant variations in response to different surface modifications of AGS, with genera such as Saprospiraceae, Terrimonas, and Ferruginibacter playing a crucial role in the formation of AGS and the removal of pollutants specifically in MnO2@SF-AGS. The charge transfer of metal ions of MnO2@SF promotes the granulation process and pollutant removal. These results highlight that MnO2@SF-AGS is an effective strategy for improving nitrogen and phosphorus removal efficiency from wastewater.

Peripheral CD4+ T helper lymphocytes alterations in major depressive disorder: A systematic review and meta-analysis.

Previous research has shown that patients with major depressive disorder (MDD) develop immune dysfunction. However, the exact alterations of cluster of differentiation (CD)4+ T helper (Th) lymphocytes in MDD remains unclear. This meta-analysis aimed to examine the specific changes in CD4+ Th cells. A comprehensive search of PubMed, EMBASE, Web of Science, and PsycINFO databases was conducted to identify studies investigating CD4+ Th, Th1, Th2, Th17, and T regulatory (Treg) cell counts in the peripheral blood of MDD patients and healthy controls (HCs), covering the period up to June 22, 2024. Our findings revealed that patients with MDD might exhibit higher CD4+ Th cells (SMD=0.26, 95 %CI, 0.02 to 0.50), CD4+/CD8+ cell ratios (SMD=0.51, 95 %CI, 0.14 to 0.89), Th1/Th2 cell ratios (SMD=0.15, 95 %CI, 0.01 to 0.30) and lower Th1 (SMD=-0.17, 95 %CI, -0.30 to -0.03), Th2 (SMD=-0.25, 95 %CI, -0.40 to -0.11), and Treg cells (SMD=-0.69, 95 %CI, -1.27 to -0.11). However, no significant difference was observed in terms of Th17 cells and Th17/Treg cell ratios between MDD patients and the HCs. Heterogeneity was large (I2:18.1-95.2 %), and possible sources of heterogeneity were explored (e.g., age, depression scale, country, and antidepressant use). Our findings indicate that peripheral CD4+ T cells in depressed patients exhibit features of adaptive immune dysfunction, as evidenced by increased CD4+ Th cells and CD4+/CD8+ and decreased Treg cells. These findings offer insights into the underlying mechanism of MDD.

Covalent versus noncovalent attachments of [FeFe]­hydrogenase models onto carbon nanotubes for aqueous hydrogen evolution reaction.

In an effort to develop the biomimetic chemistry of [FeFe]­hydrogenases for catalytic hydrogen evolution reaction (HER) in aqueous environment, we herein report the integrations of diiron dithiolate complexes into carbon nanotubes (CNTs) through three different strategies and compare the electrochemical HER performances of the as-resulted 2Fe2S/CNT hybrids in neutral aqueous medium. That is, three new diiron dithiolate complexes [{(µ-SCH2)2N(C6H4CH2C(O)R)}Fe2(CO)6] (R = N-oxylphthalimide (1), NHCH2pyrene (2), and NHCH2Ph (3)) were prepared and could be further grafted covalently to CNTs via an amide bond (this 2Fe2S/CNT hybrid is labeled as H1) as well as immobilized noncovalently to CNTs via π-π stacking interaction (H2) or via simple physisorption (H3). Meanwhile, the molecular structures of 1-3 are determined by elemental analysis and spectroscopic as well as crystallographic techniques, whereas the structures and morphologies of H1-H3 are characterized by various spectroscopies and scanning electronic microscopy. Further, the electrocatalytic HER activity trend of H1 > H2 ≈ H3 is observed in 0.1 M phosphate buffer solution (pH = 7) through different electrochemical measurements, whereas the degradation processes of H1-H3 lead to their electrocatalytic deactivation in the long-term electrolysis as proposed by post operando analysis. Thus, this work is significant to extend the potential application of carbon electrode materials engineered with diiron molecular complexes as heterogeneous HER electrocatalysts for water splitting to hydrogen.

Continuous Strain Regulation of Palladium-Gold at the Atomic Level.

Revealing the effect of surface structure changes on the electrocatalytic performance is beneficial to the development of highly efficient catalysts. However, precise regulation of the catalyst surface at the atomic level remains challenging. Here, we present a continuous strain regulation of palladium (Pd) on gold (Au) via a mechanically controllable surface strain (MCSS) setup. It is found that the structural changes induced by the strain setup can accelerate electron transfer at the solid-liquid interface, thus achieving a significantly improved performance toward hydrogen evolution reaction (HER). In situ X-ray diffraction (XRD) experiments further confirm that the enhanced activity is attributed to the increased interplanar spacing resulting from the applied strain. Theoretical calculations reveal that the tensile strain modulates the electronic structure of the Pd active sites and facilitates the desorption of the hydrogen intermediates. This work provides an effective approach for revealing the relationships between the electrocatalyst surface structure and catalytic activity.

Conservative strip tillage system in maize maintains high yield and mitigates GHG emissions but promotes N2O emissions.

Optimizing N application under straw-covered strip tillage is of great significance to the rational utilization of stover resources as well as ensure food and ecosystem security, and especially N2O emissions from agricultural systems. Quantifying N2O emissions and even the carbon footprint (CF) from agricultural systems is crucial for future protecting agricultural production systems. A two-year field experiment was conducted on black soil in Northeast China, which set up two tillage systems: strip tillage with straw returning (ST) and conventional tillage (control: CT) without straw and three nitrogen rates: 0, farmers' practice (Nfp 240 kg hm-2), and optimized nitrogen fertilizer (Nopt 180 kg hm-2). We examined the characteristics of N2O emissions and CF under the ST and CT systems. Among them, we indirectly calculated GHG emissions using the LCA method. Compared with CT, the ST system significantly reduces indirect GHG emissions, but did significantly increase direct cumulative N2O emissions by 20.7 %, most likely because the higher soil residual nitrate nitrogen content, WFPS, and soil temperature under ST was 13.0 %, 2 % and 5.7 % higher than that under CT. Nopt treatment markedly reduced cumulative N2O emissions by 36.0 %, CFarea, CFyield, and CFNPV by 22.4 %, 23.1 %, and 23.5 % in ST, respectively, compared to Nfp. The reduction in energy use of machinery in ST results in lower fuel consumption and thus generating less CF. What's more, the decrease of CFyield and CFNPV between nitrogen application treatments under ST was 5.2 % and 7.7 % higher than CT, respectively. ST system can effectively achieve higher grain yield and mitigate GHG emissions on black soil in Northeast China compared with CT, but attention should be paid to N2O emissions in the soil during the maize growth period. The sustainability of balancing GHG emissions, and economic and environmental benefits can be achieved by optimizing nitrogen fertilizer manage.

Superconductivity above 105 K in Nonclathrate Ternary Lanthanum Borohydride below Megabar Pressure.

Hydrides are promising candidates for achieving room-temperature superconductivity, but a formidable challenge remains in reducing the stabilization pressure below a megabar. In this study, we successfully synthesized a ternary lanthanum borohydride by introducing the nonmetallic element B into the La-H system, forming robust B-H covalent bonds that lower the pressure required to stabilize the superconducting phase. Electrical transport measurements confirm the presence of superconductivity with a critical temperature (Tc) of up to 106 K at 90 GPa, as evidenced by zero resistance and Tc shift under an external magnetic field. X-ray diffraction and transport measurements identify the superconducting compound as LaB2H8, a nonclathrate hydride, whose crystal structure remains stable at pressures as low as ∼ half megabar (59 GPa). Stabilizing superconductive stoichiometric LaB2H8 in a submegabar pressure regime marks a substantial advancement in the quest for high-Tc superconductivity in polynary hydrides, bringing us closer to the ambient pressure conditions.

Enhancing nitrogen removal performance using immobilized aerobic denitrifying bacteria by modified polyvinyl alcohol/sodium alginate (PVA/SA).

Aerobic denitrification has emerged as a promising and efficient method for nitrogen removal from wastewater. However, the direct application of aerobic denitrifying bacteria has faced challenges such as low nitrogen removal efficiency, bacterial loss, and poor stability. To address these issues, this study developed a novel microbial particle carrier using NaHCO3-modified polyvinyl alcohol (PVA)/sodium alginate (SA) gel (NaHCO3-PVA/SA). This carrier exhibits several advantageous properties, including excellent mass transfer efficiency, favorable biocompatibility, convenient film formation, abundant biomass, and exceptional pollutant treatment capacity. The carrier was modified with 0.3% NaHCO3, 8.0% PVA, and 1.0% SA, resulting in a remarkable 3.4-fold increase in the average pore diameter and a 12.8% improvement in mass transfer efficiency. This carrier was utilized to immobilize the aerobic denitrifying bacterium Stutzerimonas stutzeri W-2 to enhance nitrogen removal (NaHCO3-PVA/SA@W-2), resulting in a NO3--N removal efficiency of 99.06%, which was 21.39% higher than that without modification. Compared with the non-immobilized W-2, the degradation efficiency was improved by 43.70%. After five reuses, the NO3--N and TN removal rates remained at 99% and 93.01%, respectively. These results provide a solid foundation for the industrial application of the modified carrier as an effective tool for nitrogen removal in large-scale wastewater treatment processes.

Rational construction of synthetic consortia: Key considerations and model-based methods for guiding the development of a novel biosynthesis platform.

The rapid development of synthetic biology has significantly improved the capabilities of mono-culture systems in converting different substrates into various value-added bio-chemicals through metabolic engineering. However, overexpression of biosynthetic pathways in recombinant strains can impose a heavy metabolic burden on the host, resulting in imbalanced energy distribution and negatively affecting both cell growth and biosynthesis capacity. Synthetic consortia, consisting of two or more microbial species or strains with complementary functions, have emerged as a promising and efficient platform to alleviate the metabolic burden and increase product yield. However, research on synthetic consortia is still in its infancy, with numerous challenges regarding the design and construction of stable synthetic consortia. This review provides a comprehensive comparison of the advantages and disadvantages of mono-culture systems and synthetic consortia. Key considerations for engineering synthetic consortia based on recent advances are summarized, and simulation and computational tools for guiding the advancement of synthetic consortia are discussed. Moreover, further development of more efficient and cost-effective synthetic consortia with emerging technologies such as artificial intelligence and machine learning is highlighted.

Portable photoelectrochemical immunoassay with micro-electro-mechanical-system for alpha-fetoprotein in hepatocellular carcinoma.

Early detection of cancer has a profound impact on patient survival and treatment outcomes considering high treatment success rates and reduced treatment complexity. Here, we developed a portable photoelectrochemical (PEC) immune platform for sensitive testing of alpha-fetoprotein (AFP) based on Pt nanocluster (Pt NCs) loaded defective-state g-C3N4 photon-electron transducers. The broad forbidden band structure of g-C3N4 was optimized by the nitrogen doping strategy and additional homogeneous porous structure was introduced to further enhance the photon utilization. In addition, the in-situ growth of Pt NCs provided efficient electron transfer catalytic sites for sacrificial agents, which were used to further improve the sensitivity of the sensor. Efficient photoelectric conversion under a hand-held flashlight was determined by the geometry of the transducer and the energy band design, and the portable design of the PEC sensor was realized. The developed sensing platform exhibited a wide linear response range (0.1-50 ng mL-1) and low limit of detection (0.043 ng mL-1) for AFP under optimum conditions. This work provides a new idea for designing portable PEC biosensing platforms to meet the current mainstream POC testing needs.

Reconfigurable Tri-Mode Metasurface for Broadband Low Observation, Wide-Range Tracing, and Backscatter Communication.

In the current prevalent complex electromagnetic (EM) environment, intelligent methods for versatile and integrated control of EM waves using compact devices are both essential and challenging. These varied wave control objectives can at times conflict with one another, such as the need for broad absorption to remain inconspicuous, while also requiring enhanced backward scattering for highly reliable tracing and secure communication. To address these sophisticated challenges, a microwave-frequency reconfigurable tri-mode metasurface (RTMM) is introduced. The proposed innovation enables three distinct operational modes: broadband low observation, enhanced EM wave tracing, and backscatter communication over a wide-angle range by simple control of the PIN diodes embedded in each meta-atom. The proof-of-concept demonstration of the fabricated prototype verified the switchable tri-mode performance of the RTMM. This proposed RTMM can be adapted to various applications, including EM shielding, target detection, and secure communication in complex and threatening EM environments, paving the way for environmentally-adaptive EM wave manipulation.

An aldose reductase inhibitor, WJ-39, ameliorates renal tubular injury in diabetic nephropathy by activating PINK1/Parkin signaling.

Renal tubular injury is a critical factor during the early stages of diabetic nephropathy (DN). Proximal tubular epithelial cells, which contain abundant mitochondria essential for intracellular homeostasis, are susceptible to disruptions in the intracellular environment, making them especially vulnerable to diabetic state disorders, which may be attributed to their elevated energy requirements and reliance on aerobic metabolism. It is widely thought that overactivation of the polyol pathway is implicated in DN pathogenesis, and inhibition of aldose reductase (AR), the rate-limiting enzyme in this pathway, represents a promising therapeutic avenue. WJ-39, a novel aldose reductase inhibitor, was investigated in this study for its protective effects on renal tubules in DN and the underlying mechanisms. Our findings revealed that WJ-39 significantly ameliorated the renal tubular morphology in high-fat diet (HFD)/streptozotocin (STZ)-induced DN rats, concurrently inhibiting fibrosis. Notably, WJ-39 safeguarded the structure and function of renal tubular mitochondria by enhancing mitochondrial dynamics. This involved the regulation of mitochondrial fission and fusion proteins and the promotion of PTEN-induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy. Furthermore, WJ-39 demonstrated the inhibition of endogenous apoptosis by mitigating the production of mitochondrial reactive oxygen species (ROS). The protective effects of WJ-39 on mitochondria and apoptosis were countered in high glucose-treated HK-2 cells upon transfection with PINK1 siRNA. Overall, our findings suggest that WJ-39 protects the structural and functional integrity of renal tubules in DN, which may be attributed to its capacity to inhibit aldose reductase activity, activate the PINK1/Parkin signaling pathway, promote mitophagy, and alleviate apoptosis.

Bidirectional relationship between borderline personality features and depressive symptoms in early adolescence: A school-based cohort study.

Depressive symptoms is a public health concern worldwide, and adolescents may experience more depressive symptoms. Although the relationship between borderline personality features (BPFs) disorder and depressive symptoms has been established, it is unclear whether the longitudinal relationship between them is unidirectional or bidirectional and whether these symptoms are different between boys and girls. In this study, Chinese adolescents (1608 total and separately 972 for boys and 636 girls) were enrolled between September 2019 and September 2021, and we analyzed the data using a cross-lagged model. The results suggested a bidirectional relationship between BPFs and depressive symptoms in boys (ß = 0.191 and 0.117, P < 0.001). However, in girls, depressive symptoms were predicted based on BPFs (ß = 0.225, P < 0.001), whereas BPFs were not predicted based on depressive symptoms (ß = 0.035, P = 0.535). The findings suggest that borderline personality traits and depressive symptoms are only bilaterally associated in girls, which also provides important evidence for the treatment and prevention of adolescent BPFs and depressive symptoms.

Self-Organized Evolution of the Internal Transport Barrier in Ion-Temperature-Gradient Driven Gyrokinetic Turbulence.

Understanding the self-organization of the most promising internal transport barrier in fusion plasmas needs a long-time nonlinear gyrokinetic global simulation. The neighboring equilibrium update method is proposed, which solves the secularity problem in a perturbative simulation and speeds up the numerical computation by more than 10 times. It is found that the internal transport barrier emerges at the magnetic axis due to inward propagated turbulence avalanche, and its outward expansion is the catastrophe of self-organized structure induced by outward propagated avalanche.

In Vivo Analysis of Acromioclavicular Kinematics and Distance During Multiplanar Humeral Elevation.

BACKGROUND: Knowledge of acromioclavicular (AC) joint kinematics and distance may provide insight into the biomechanical function and development of new treatment methods. However, accurate data on in vivo AC kinematics and distance between the clavicle and acromion remain unknown. PURPOSE/HYPOTHESIS: The purpose of this study was to investigate 3-dimensional AC kinematics and distance during arm elevation in abduction, scaption, and forward flexion in a healthy population. It was hypothesized that AC kinematics and distance would vary with the elevation angle and plane of the arm. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 19 shoulders of healthy participants were enrolled. AC kinematics and distance were investigated with a combined dual fluoroscopic imaging system and computed tomography. Rotation and translation of the AC joint were calculated. The AC distance was measured as the minimum distance between the medial border of the acromion and the articular surface of the distal clavicle (ASDC). The minimum distance point (MDP) ratio was defined as the length between the MDP and the posterior edge of the ASDC divided by the anterior-posterior length of the ASDC. AC kinematics and distance between different elevation planes and angles were compared. RESULTS: Progressive internal rotation, upward rotation, and posterior tilt of the AC joint were observed in all elevation planes. The scapula rotated more upward relative to the clavicle in abduction than in scaption (P = .002) and flexion (P = .005). The arm elevation angle significantly affected translation of the AC joint. The acromion translated more laterally and more posteriorly in scaption than in abduction (P < .001). The AC distance decreased from the initial position to 75° in all planes and was significantly greater in flexion (P < .001). The MDP ratio significantly increased with the elevation angle (P < .001). CONCLUSION: Progressive rotation and significant translation of the AC joint were observed in different elevation planes. The AC distance decreased with the elevation angle from the initial position to 75°. The minimum distance between the ASDC and the medial border of the acromion moved anteriorly as the shoulder elevation angle increased. CLINICAL RELEVANCE: These results could serve as benchmark data for future studies aiming to improve the surgical treatment of AC joint abnormalities to restore optimal function.

Multicolor emissive carbon dot-based fluorometric analysis platform for rapid quantification and discrimination of nitroimidazole antibiotic residues.

The development of efficient, rapid, portable, and accurate analysis of veterinary drug residues in food matrices is in great demand for food safety assessment. Here, we have developed a smartphone-integrated platform for fluorometric quantification of metronidazole (MNZ) residues and constructed a sensor array for discrimination of different nitroimidazole antibiotics (NIIMs). Multicolor CDs (B-CDs, C-CDs, Y-CDs, and R-CD) were prepared and showed different fluorescence response to MNZ. The fluorescence of C-CDs was quenched Because of the inner filter effect (IFE) between the C-CDs and MNZ, while that of R-CDs was enhanced due to the passivation of surface defects by MNZ. Based on the response pattern, the fluorometric quantification of MNZ based on the fluorescence images of C-CD + R-CD system (R/G values) was achieved with a low detection limit of 0.45 µM. By designing a smartphone-integrated platform, the analysis can be completed within 20 min. In addition, a fluorescence sensor array based C-CDs and R-CDs was also developed. The unique fingerprint of each NIIMs was obtained by linear discriminant analysis (LDA) of the response patterns, indicating an effective discrimination of five NIIMs. Moreover, the platform was used for quantification of MNZ in food samples and the recoveries were within 84.0-106.3 % with relative standard deviations 1.2-10.2 %. Therefore, the proposed method shows great potential as a universal platform for rapid detection of veterinary drug residues.

Organocatalytic diastereo- and atroposelective construction of N-N axially chiral pyrroles and indoles.

The construction of N-N axially chiral motifs is an important research topic, owing to their wide occurrence in natural products, pharmaceuticals and chiral ligands. One efficient method is the atroposelective dihydropyrimidin-4-one formation. We present herein a direct catalytic synthesis of N-N atropisomers with simultaneous creation of contiguous axial and central chirality by oxidative NHC (N-heterocyclic carbenes) catalyzed (3 + 3) cycloaddition. Using our method, we are able to synthesize structurally diverse N-N axially chiral pyrroles and indoles with vicinal central chirality or bearing a 2,3-dihydropyrimidin-4-one moiety in moderate to good yields and excellent enantioselectivities. Further synthetic transformations of the obtained axially chiral pyrroles and indoles derivative products are demonstrated. The reaction mechanism and the origin of enantioselectivity are understood through DFT calculations.