Discovery of Cinnamic Acid Derivatives as Potent Anti-H. pylori Agents.

Antibiotics are currently used for the treatment of Helicobacter pylori (H. pylori), which is confirmed to be the major cause of gastric disorders. However, the long-term consumption of antibiotics has already caused antibiotic resistance and side effects in vivo. Therefore, there is an emerging need for searching for safe and effective anti-H. pylori agents. Inspired by the excellent bioactivities of cinnamic acid, a series of cinnamic acid derivatives (compounds 1-30) were synthesized and determined for H. pylori inhibition. The initial screening revealed that compound 23, a 2,4-dinitro cinnamic acid derivative containing 4-methoxyphenol, showed excellent H. pylori inhibition with an MIC value of 4 µM. Further studies indicated that compound 23 showed anti-bacterial activity and had a bactericidal effect on H. pylori due to the destruction of the bacterial structure. Molecular docking analysis revealed that the 2,4-dinitro groups in cinnamic acid moiety formed hydrogen bonding with amino acid residues in an active pocket of H. pylori protein. Interestingly, the ester moiety fitted into the hydrophobic pocket, attaining additional stability to compound 23. Above all, the present study reveals that compound 23 could be considered a promising anti-H. pylori agent to treat H. pylori causing gastritis.

The Potential Related Genes and Mechanisms Involved in Improving the Treadmill Exercise Ability of APP/PS1 Mice.

Alzheimer's disease (AD) causes a decline in skeletal muscle function, which can further exacerbate the cognitive dysfunction of patients with AD. It has been widely established that exercise improves AD brain pathology, but the role of skeletal muscle in AD is still poorly understood. In this study, we investigated the effects of treadmill exercise on the exercise ability of APP/PS1 transgenic AD mice and explored potential gene expression changes in their skeletal muscle. The APP/PS1 mice were subjected to a treadmill exercise for 12 weeks, followed by the Morris water maze and the open field test. After behavioral experiments, the changes in morphology, area, collagen fiber deposition, and ultrastructure of the skeletal muscle were determined; the balance of skeletal muscle protein synthesis and decomposition was analyzed; and changes in gene expression were investigated using RNA-Seq. We found that this exercise strategy can promote the learning and memory abilities of AD mice, reduce their anxiety-like behavior, improve their exercise ability, alleviate skeletal muscle atrophy, and optimize the microstructure. It can also enhance skeletal muscle protein synthesis and decomposition and improve several signaling pathways, such as the JAK-STAT, Wnt, and NOD-like receptors while decreasing calcium, cAMP, cGMP-PKG, and other signaling pathways. Six KEGG enrichment signaling pathways were downregulated and five signaling pathways were upregulated in the AD mice compared with wild-type mice, and these pathways were precisely reversed after the treadmill exercise. The expression of transcription factors such as Fosb and Egr1 in the skeletal muscle of AD mice decreased, followed by a decrease in the regulated target genes Socs1, Srrm4, and Il1b, a trend that was reversed following the exercise intervention. After exercise, AD mice exhibited a similar gene expression to that of wild-type mice, indicating enhanced exercise ability. The potential regulatory pathways and related genes identified in this study provide valuable insights for the clinical management and treatment of AD.

Harnessing plasticity in sequential metamaterials for ideal shock absorption.

Mechanical metamaterials exhibit interesting properties such as high stiffness at low density1-3, enhanced energy absorption3,4, shape morphing5-7, sequential deformations8-11, auxeticity12-14 and robust waveguiding15,16. Until now, metamaterial design has primarily relied on geometry, and materials nonlinearities such as viscoelasticity, fracture and plasticity have been largely left out of the design rationale. In fact, plastic deformations have been traditionally seen as a failure mode and thereby carefully avoided1,3,17,18. Here we embrace plasticity instead and discover a delicate balance between plasticity and buckling instability, which we term 'yield buckling'. We exploit yield buckling to design metamaterials that buckle sequentially in an arbitrary large sequence of steps whilst keeping a load-bearing capacity. We make use of sequential yield buckling to create metamaterials that combine stiffness and dissipation-two properties that are usually incompatible-and that can be used several times. Hence, our metamaterials exhibit superior shock-absorption performance. Our findings add plasticity to the metamaterial toolbox and make mechanical metamaterials a burgeoning technology with serious potential for mass production.

Activation of NOD1 on tumor-associated macrophages augments CD8+ T cell-mediated antitumor immunity in hepatocellular carcinoma.

The efficacy of immunotherapy targeting the PD-1/PD-L1 pathway in hepatocellular carcinoma (HCC) is limited. NOD-like receptors (NLRs) comprise a highly evolutionarily conserved family of cytosolic bacterial sensors, yet their impact on antitumor immunity against HCC remains unclear. In this study, we uncovered that NOD1, a well-studied member of NLR family, exhibits predominant expression in tumor-associated macrophages (TAMs) and correlates positively with improved prognosis and responses to anti-PD-1 treatments in patients with HCC. Activation of NOD1 in vivo augments antitumor immunity and enhances the effectiveness of anti-PD-1 therapy. Mechanistically, NOD1 activation resulted in diminished expression of perilipin 5, thereby hindering fatty acid oxidation and inducing free fatty acid accumulation in TAMs. This metabolic alteration promoted membrane localization of the costimulatory molecule OX40L in a lipid modification-dependent manner, thereby activating CD8+ T cells. These findings unveil a previously unrecognized role for NOD1 in fortifying antitumor T cell immunity in HCC, potentially advancing cancer immunotherapy.

CoFe2O4 with the In-Situ Formed Oxygen Vacancies and Co Particles as an Efficient Bifunctional Catalyst for Rechargeable Zinc-Air Batteries.

Rechargeable zinc-air batteries (RZABs) are considered as one of the most promising clean energy device due to their abundant resources, low cost and environmental friendliness. However, their energy efficiency and cycle life are far from satisfactory due to the poor activity and stability of bi-functional electrocatalyst in air cathode. In this work, an efficient bi-functional catalyst (rGO-CoFe2O4/Co) was derived from its precursor (rGO-CoFe2O4) through a simple annealing process. Electrochemical measurements prove that rGO-CoFe2O4/Co with the in-situ formed Co nano particles and rich oxygen vacancies appears excellent oxygen reduction reaction and oxygen evolution reaction catalytic activity compared to its counterpart. Its half-wave potential is 0.81 V (vs RHE) and the OER overpotential is only 310 mV (vs RHE). In addition, rechargeable zinc-air batteries assembled with rGO-CoFe2O4/Co show the highest peak power density (128.9 mW cm-2) and cycling stability compared to rGO-CoFe2O4 and commercial Pt/C-RuO2 catalysts. This work provides a simple strategy for the design of advanced bifunctional catalysts.

Genomic profiling of cell-free DNA from dogs with benign and malignant tumors.

OBJECTIVE: Cancer is currently the most common cause of death in adult dogs. Like humans, dogs have a one-third chance of developing cancer in their lifetime. We used shallow whole-genome sequencing (sWGS) to analyze blood cell-free DNA (cfDNA) from four tumor-bearing dogs (one with benign and three with malignant tumors) and 38 healthy dogs. RESULTS: Similar to the results observed in the healthy dogs, no copy number aberration (CNA) was detected in the dog with benign lipomas, and the distribution of cfDNA fragment size (FS) closely resembled that of the healthy dogs. However, among the three dogs diagnosed with malignant tumors, two dogs exhibited varying degrees and quantities of CNAs. Compared to the distribution of FS in the healthy dogs, the cancer dogs exhibited a noticeable shift towards shorter lengths. These findings indicated that CNA and FS profiles derived from sWGS data can be used for non-invasive cancer detection in dogs.

Exercise-promoted adiponectin secretion activates autolysosomes to protect the liver of ApoE-/- mice from a high-fat diet.

Fat is a "double-edged sword": while it is a necessary substance for the body, the long-term intake of excessive fat will cause obesity, with the liver subjected to lipotoxicity as it accumulates. It will then continue to deteriorate, eventually leading to liver failure, which is a negative impact of high-fat food intake. Research has shown that exercise can reverse the side effects of a chronic high-fat diet and help the body to mitigate the harmful effects of lipotoxicity. In our study, it was found that moderate-intensity cardio-training (MICT) and high-intensity interval exercise (HIIT) effectively protected the livers of high-fat diet (HFD) ApoE-/- mice against lipotoxicity. Previous results demonstrated that 12 weeks of HFD resulted in a significant elevation of CD36 in the livers of C57BL/6J mice, while knockdown of CD36 did not reduce the accumulation of fat in the liver. Therefore, we used ApoE-/- mice as experimental subjects. Although HFD caused the development of hyperlipidemia and atherosclerosis, it is interesting to note that, due to the knockdown of ApoE, the livers of ApoE-/- mice in the non-exercise group did not show significant lipid deposition; however, after 12 weeks of MICT and HIIT, the livers of ApoE-/- mice showed significant lipid deposition. After we analyzed the lipid metabolism in their livers, we found that this was caused by the promotion of transport of peripheral fat into the liver due to exercise. Moreover, 12 weeks of exercise effectively reduced atherosclerosis, and the livers of ApoE-/- mice in the exercise group were not damaged by lipotoxicity. The results showed that a 12-week exercise treatment activated AMPK in the livers of HFD ApoE-/- mice through the APN-AdipoR1 signaling pathway, improved hepatic lipid metabolism disorders, and promoted the nuclear translocation of TFEB to enhance autophagic-lysosomal lipid scavenging. After the peripheral lipid is input into the liver due to exercise, the energy generated through gluconeogenesis can be used to replenish the energy consumed by exercise and maintain the normal operation of various functions in the liver, based on which the high autophagic flux in the liver can be maintained and the lipid clearance rate can be enhanced to protect the liver from lipotoxicity.

Optimized irrigation and fertilization can mitigate negative CO2 impacts on seed yield and vigor of hybrid maize.

Seed yield and vigor of hybrid maize determine the planting, yield, and quality of maize, and consequently affect food, nutrition, and livelihood security; however, the response of seed yield and vigor to climate change is still unclear. We established an optimization-simulation framework consisting of a water­nitrogen crop production function, a seed vigor and a gridded process-based model to optimize irrigation and nitrogen fertilization management, and used it to evaluate seed yield and vigor in major seed production locations of China, the USA, and Mexico. This framework could reflect the influence of water and nitrogen inputs at different stages on seed yield and vigor considering the spatio-temporal variability of climate and soil properties. Projected seed yield and vigor decreased by 5.8-9.0 % without adaptation by the 2050s, due to the 1.3-5.8 % decrease in seed number and seed protein concentration. Seed yield was positively correlated with CO2 and negatively correlated with temperature, while seed vigor depended on the response of components of seed vigor to climatic factors. Under optimized management, the direct positive effects of temperature on seed protein concentration and CO2 on seed number were strengthened, and the direct negative effects of temperature on seed number and CO2 on seed protein concentration were weakened, which mitigated the reductions in both seed yield and vigor. Elevated CO2 was projected to exacerbate the 2.6 % seed vigor reduction and mitigate the 2.9 % seed yield loss without adaptation, while optimized management could increase seed yield by 4.1 % and mitigate the 2.2 % seed vigor reduction in the Hexi Corridor of China, and decrease the seed yield and vigor reduction by 2.4-5.8 % in the USA and Mexico. Optimized management can strengthen the positive and mitigate the negative effects of climate change on irrigated hybrid maize and inform high-yield and high-quality seed production globally.

Guest-Induced Helical Superstructure from a Gold Nanocluster-Based Supramolecular Organic Framework Enables Efficient Catalysis.

Mimicking hierarchical assembly in nature to exploit atomically precise artificial systems with complex structures and versatile functions remains a long-standing challenge. Herein, we report two single-crystal supramolecular organic frameworks (MSOF-4 and MSOF-5) based on custom-designed atomically precise gold nanoclusters Au11(4-Mpy)3(PPh3)7, showing distinct and intriguing host-guest adaptation behaviors toward 1-/2-bromopropane (BPR) isomers. MSOF-4 exhibits sev topology and cylindrical channels with 4-mercaptopyridine (4-Mpy) ligands matching well with guest 1-BPR. Due to the confinement effect, solid MSOF-4 undergoes significant structural change upon selective adsorption of 1-BPR vapor over 2-BPR, resulting in strong near-infrared fluorescence. Single-crystal X-ray diffraction reveals that Au11(4-Mpy)3(PPh3)7 in MSOF-4 transforms into Au11Br3(PPh3)7 upon ligand exchange with 1-BPR, resulting in 1-BPR@MSOF-6 single crystals with a rarely reported helical assembly structure. Significantly, the double-helical structure of MSOF-6 facilitates efficient catalysis of the electron transfer (ET) reaction, resulting in a nearly 6 times increase of catalytic rates compared with MSOF-4. In sharp contrast, solid MSOF-5 possesses chb topology and cage-type channels with narrow windows, showing excellent selective physical adsorption toward 1-BPR vapor but a nonfluorescent feature upon guest adsorption. Our results demonstrate a powerful strategy for developing advanced assemblies with high-order complexity and engineering their functions in atomic precision.

DDR2/STAT3 Positive Feedback Loop Mediates the Immunosuppressive Microenvironment by Upregulating PD-L1 and Recruiting MDSCs in Oxaliplatin-Resistant HCC.

BACKGROUND AND AIMS: Transcriptome sequencing revealed high expression of DDR2 in oxaliplatin-resistant hepatocellular carcinoma (HCC). This study aimed to explore the role of DDR2 in oxaliplatin resistance and immune evasion in HCC. METHODS: Oxaliplatin-resistant HCC cell lines were established. The interaction between DDR2 and STAT3 was investigated, along with the mechanisms involved in DDR2/STAT3-mediated PD-L1 upregulation and polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) accumulation both in vitro and in vivo. RESULTS: DDR2 was found to induce the phosphorylation of STAT3, leading to its nuclear translocation. Conversely, the activation of STAT3 enhanced DDR2 expression. A positive feedback loop involving DDR2/STAT3 was identified in oxaliplatin-resistant HCC, which was associated with PD-L1 upregulation and PMN-MDSCs accumulation. Knockdown of DDR2 and STAT3 sensitized oxaliplatin-resistant HCC cells to oxaliplatin and resulted in decreased PMN-MDSCs and increased CD8+ T cells in the tumor microenvironment. Enzyme-linked immunosorbent array and MDSC transwell migration assays indicated that oxaliplatin-resistant HCC cells recruited PMN-MDSCs through CCL20. Dual luciferase reporter assays demonstrated that STAT3 can directly enhance the transcription of PD-L1 and CCL20. Furthermore, treatment with a PD-L1 antibody in combination with CCL20 blockade had significant antitumor effects on oxaliplatin-resistant HCC. CONCLUSIONS: Our findings revealed a positive feedback mechanism involving DDR2 and STAT3 that mediates the immunosuppressive microenvironment and promotes oxaliplatin resistance and immune evasion via PD-L1 upregulation and PMN-MDSC recruitment. Targeting the DDR2/STAT3 pathway may be a promising therapeutic strategy to overcome immune escape and chemoresistance in HCC.

Association between ambient fine particular matter components and subsequent cognitive impairment in community-dwelling older people: a prospective cohort study from eastern China.

BACKGROUND: Fine particular matter (PM2.5) has been associated with dementia, but limited information is available regarding the association between PM2.5 components and dementia. AIMS: We aimed to identify the major components of PM2.5 that affect cognitive function to further investigate its mechanism of action, and develop a prevention strategy for dementia. METHODS: In this study, we included 7804 participants aged ≥ 60 years recruited from seven counties in Zhejiang province, eastern China. The participants completed the baseline survey between 2014 and 2015, and were followed up until the end of 2020. We adopted single-component robust Poisson regression models for analyses, and estimated relative risks and 95% confidence intervals describing associations between the chemical constituents of PM2.5 exposure and incident cognitive impairment in those who were free from cognitive impairment at baseline. RESULTS: Significantly positive associations were observed between sulfate, nitrate, ammonium, and organic matter in PM2.5 and incident cognitive impairment across different exposure periods; the relative risks of 10-year exposure before enrollment ranged from 1.01 to 1.02. However, we did not find a significant association between black carbon and cognitive impairment. The point estimates of the relative risk values did not change substantially after performing the sensitivity analyses. CONCLUSIONS: Our findings strengthen the idea that long-term exposure to PM2.5 mass and its chemical components is associated with an elevated risk of incident cognitive impairment among older adults.

CD276 Promotes an Inhibitory Tumor Microenvironment in Hepatocellular Carcinoma and is Associated with Poor Prognosis.

Background: CD276 is an emerging immune checkpoint molecule that has been implicated in various cancers. However, its specific role in hepatocellular carcinoma (HCC) remains unclear. This study examined the impact of CD276 on patient prognosis and the tumor microenvironment (TME). Methods: The Cancer Genome Atlas (TCGA) database was utilized to evaluate CD276 expression in HCC and the association between CD276 and immune indicators was also analyzed. The signaling pathways correlated with CD276 expression were identified by gene set enrichment analysis (GSEA). Different algorithms were used to assess immune cell infiltration. The effect of CD276 knockdown on HCC cell phenotypes and its relationship with macrophage polarization was examined using the cell counting kit 8 (CCK-8) assay and co-culture system. Results: CD276 was upregulated in HCC and associated with unfavorable clinical outcomes. Hgh CD276 expression was associated with enrichment of the G2/M checkpoint, E2F targets, and mitotic spindles. CD276 expression was correlated with the infiltration of immune cells, including high level of tumor-associated macrophages and low levels of CD8+ T cells. Knockdown of CD276 decreased HCC cell proliferation and increased apoptosis. CD276 silencing in HCC cells and co-culture with THP-1-derived macrophages had a regulatory effect on macrophage polarization and macrophage-mediated cell proliferation and migration. Conclusion: CD276 expression in HCC is associated with unfavorable clinical outcomes and may contribute to the development of an immunosuppressive microenvironment. Specifically, CD276 was associated with alterations in immune cell infiltration, immune marker expression, and macrophage polarization during HCC progression, suggesting its potential as a prognostic indicator and promising target for immunotherapeutic intervention in HCC.

High-precision spatiotemporal three-dimensional ultrashort pulse synchronization with optical Kerr effect.

In studying the interaction of multiple ultrashort pulses with matter, high requirements are put forward for spatiotemporal synchronization accuracy. Limited by the response time and bandwidth of existing devices, the synchronization of multiple ultrashort pulses still faces significant difficulties. By observing the transient phenomena of the optical Kerr effect, high-precision, three-dimensional (x, y, t) synchronization of ultrashort pulses at different angles was achieved. In the optical Kerr effect, the polarization state of the signal pulse changes only when it coincides with the pump pulse, at which point the signal pulse passes through the analyzer. The changes in the intensity and phase of the signal pulse is positively correlated with the degree of spatiotemporal coincidence. In this study, 10-ps pulses were used in the experiments. By observing the intensity and phase distribution of the signal pulses, a time synchronization accuracy between two pulses of less than 1 ps and spatial synchronization accuracy of ±125 µm and ±3 µm in the x and y directions, respectively, were achieved. Moreover, the synchronization of two pulses at an angle of 90 ° was measured, further proving that the method can achieve the spatiotemporal synchronization of pulses with large angles. Therefore, this method has important application prospects in the study of multi-beam interactions with matter and other ultrafast physical phenomena.

High-intensity interval training and medium-intensity continuous training may affect cognitive function through regulation of intestinal microbial composition and its metabolite LPS by the gut-brain axis.

AIMS: The gut-brain axis is the communication mechanism between the gut and the central nervous system, and the intestinal flora and lipopolysaccharide (LPS) play a crucial role in this mechanism. Exercise regulates the gut microbiota composition and metabolite production (i.e., LPS). We aimed to investigate the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on cognitive function in C57BL/6 J mice through gut-brain axis regulation of gut microbiota composition and LPS displacement. MAIN METHODS: C57BL/6 J male mice were randomly divided into sedentary, HIIT, and MICT groups. After 12 weeks of exercise intervention, the cognitive function of the brain and mRNA levels of related inflammatory factors were measured. RNA sequencing, Golgi staining, intestinal microbial 16 s rDNA sequencing, and ELISA were performed. KEY FINDINGS: HIIT and MICT affect brain cognitive function by regulating the gut microbiota composition and its metabolite, LPS, through the gut microbiota-gut-brain axis. HIIT is suspected to have a risk: it can induce "intestinal leakage" by regulating intestinal permeability-related microbiota, resulting in excessive LPS in the blood and brain and activating M1 microglia in the brain, leading to reduced dendritic spine density and affecting cognitive function. SIGNIFICANCE: This study revealed a potential link between changes in the gut microbiota and cognitive function. It highlighted the possible risk of HIIT in reducing dendritic spine density and affecting cognitive function.

Elevating Discharge Voltage of Li2CO3-Routine Li-CO2 Battery over 2.9†V at an Ultra-Wide Temperature Window.

The Li-CO2 batteries utilizing greenhouse gas CO2 possess advantages of high energy density and environmental friendliness. However, these batteries following Li2CO3-product route typically exhibit low work voltage (<2.5 V) and energy efficiency. Herein, we have demonstrated for the first time that cobalt phthalocyanine (CoPc) as homogeneous catalyst can elevate the work plateau towards 2.98 V, which is higher than its theoretical discharge voltage without changing the Li2CO3-product route. This unprecedented discharge voltage is illustrated by mass spectrum and electrochemical analyses that CoPc has powerful adsorption capability with CO2 (-7.484 kJ mol-1) and forms discharge intermediate of C33H16CoN8O2. Besides high discharge capacity of 18724 mAh g-1 and robust cyclability over 1600 hours (1000 mAh g-1 cut-off) at a current density of 100 mA g-1, the batteries show high temperature adaptability (-30-80 °C). Our work is paving a promising avenue for the progress of high-efficiency Li-CO2 batteries.

High-Entropy Configuration Strategy to Build High Performance Na-Ion Layered Oxide Cathodes Derived from Simple Techniques.

Layered transition metal oxides are commonly used as the cathode materials in sodium-ion batteries due to their low cost and easy manufacturing. However, the application is hindered by poor rate performance and complex phase transitions. To address these challenges, a new seven-component high-entropy layered oxide cathode material, O3-NaNi0.25Fe0.15Mn0.3Ti0.1Sn0.05Co0.05Li0.1O2 (HEO) has been developed. The entropy stabilization effect plays a crucial role in improving the performance of electrochemical systems and the stability of structures. The HEO exhibits a specific discharge capacity of 154.1 mA h g-1 at 0.1 C and 94.5 mA h g-1 at 7 C. In-situ and ex-situ XRD results demonstrate that the HEO effectively retards complex phase transitions. This work provides a high-entropy design for the storage materials with a high energy density. Meanwhile, it eliminates industry doubts about the performance of sodium ion layered oxide cathode materials.

Giant dielectric tunability in ferroelectric ceramics with ultralow loss by ion substitution design.

Due to their responsiveness to modulation by external direct current fields, dielectric tunable materials are extensively utilized in integrated components, such as ferroelectric phase shifters. Barium strontium titanate ceramics have been considered the most potential tunable materials for a long time. However, the significant dielectric loss and high voltage drive have limited their further applications. Recently, Bi6Ti5WO22 ceramic has regained attention for its high dielectric tunability with low loss. In this study, we judiciously introduce Nb5+ with a larger ionic radius, replacing Ti4+ and W6+. This successful substitution enables the modulation of the phase transition temperature of Bi6Ti5WO22 ceramics to room temperature, resulting in superior tunable properties. Specifically, the 0.7Bi6Ti5WO22-0.3Bi6Ti4Nb2O22 ceramics exhibit giant tunability (~75.6%) with ultralow loss (<0.002) under a low electric field (1.5 kV/mm). This tunability is twice that of barium strontium titanate ceramics with a similar dielectric constant and only one-tenth of the loss. Neutron powder diffraction and transmission-electron-microscopy illustrate the nanodomains and micro-strains influenced by ion substitution. Density functional theory simulation calculations reveal the contribution of ion substitution to polarization. The research provides an ideal substitute for tunable material and a general strategy for adjusting phase transition temperature to improve dielectric properties.

Nickel-catalyzed switchable arylative/endo-cyclization of 1,6-enynes.

Carbo- and heterocycles are frequently used as crucial scaffolds in natural products, fine chemicals, and biologically and pharmaceutically active compounds. Transition-metal-catalyzed cyclization of 1,6-enynes has emerged as a powerful strategy for constructing functionalized carbo- and heterocycles. Despite significant progress, the regioselectivity of alkyne functionalization is entirely substrate-dependent. And only exo-cyclization/cross-coupling products can be obtained, while endo-selective cyclization/cross-coupling remains elusive and still poses a formidable challenge. In this study, we disclose a nickel-catalyzed switchable arylation/cyclization of 1,6-enynes in which the nature of the ligand dictates the regioselectivity of alkyne arylation, while the electrophilic trapping reagents determine the selectivity of the cyclization mode. Specifically, using a commercially available 1,10-phenanthroline as a ligand facilitates trans-arylation/cyclization to obtain seven-membered ring products, while a 2-naphthyl-substituted bisbox ligand promotes cis-arylation/cyclization to access six-membered ring products. Diastereoselective cyclizations have also been developed for the synthesis of enantioenriched piperidines and azepanes, which are core structural elements of pharmaceuticals and natural products possessing important biological activities. Furthermore, experimental and density functional theory studies reveal that the regioselectivity of the alkyne arylation process is entirely controlled by the steric hindrance of the ligand; the reaction mechanism involves exo-cyclization followed by Dowd-Beckwith-type ring expansion to form endo-cyclization products.

Monocular vision-based dynamic calibration method for determining the sensitivities of low-frequency tri-axial vibration sensors.

Low-frequency vibrations exist widely in the natural environment and in human activities. Low-frequency tri-axial vibration sensors are enormously applied in the fields of seismic monitoring, building structure health monitoring, aerospace navigating, etc. Their sensitivity calibration accuracy directly determines whether their applications can work reliably. Although the laser interferometry recommended by the International Standardization Organization (ISO) is commonly used to achieve the vibration calibration, it suffers from the shortages of low-frequency range, high cost, low efficiency, and limited applicable environment. In this study, a novel monocular vision-based dynamic calibration method is proposed, which determines the whole sensitivities of tri-axial sensors by the monocular vision method to accurately measure the spatial input excitation. This method improves the calibration performance by eliminating the installation error and enhancing calibration efficiency via decreasing reinstallations. The experimental results compared with the laser interferometry demonstrate that the investigated method can obtain similar calibration accuracy in the range of 0.16-2 Hz with more efficiency. The corresponding maximum relative deviations of X-, Y-, and Z-axial sensitivities were approximately 2.5%, 1.8%, and 0.4%. In addition, the maximum relative standard deviation of the investigated method was only about 0.3% in this range.

UFObow: A single-wavelength excitable Brainbow for simultaneous multicolor ex-vivo and in-vivo imaging of mammalian cells.

Brainbow is a genetic cell-labeling technique that allows random colorization of multiple cells and real-time visualization of cell fate within a tissue, providing valuable insights into understanding complex biological processes. However, fluorescent proteins (FPs) in Brainbow have distinct excitation spectra with peak difference greater than 35 nm, which requires sequential imaging under multiple excitations and thus leads to long acquisition times. In addition, they are not easily used together with other fluorophores due to severe spectral bleed-through. Here, we report the development of a single-wavelength excitable Brainbow, UFObow, incorporating three newly developed blue-excitable FPs. We have demonstrated that UFObow enables not only tracking the growth dynamics of tumor cells in vivo but also mapping spatial distribution of immune cells within a sub-cubic centimeter tissue, revealing cell heterogeneity. This provides a powerful means to explore complex biology in a simultaneous imaging manner at a single-cell resolution in organs or in vivo.