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1.
Neural Regen Res ; 20(1): 277-290, 2025 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38767492

RESUMO

JOURNAL/nrgr/04.03/01300535-202501000-00035/figure1/v/2024-05-14T021156Z/r/image-tiff Our previous study found that rat bone marrow-derived neural crest cells (acting as Schwann cell progenitors) have the potential to promote long-distance nerve repair. Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication. Nevertheless, the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear. To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves, we collected conditioned culture medium from hypoxia-pretreated neural crest cells, and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation. The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells. We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells. Subsequently, to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons, we used a microfluidic axonal dissociation model of sensory neurons in vitro, and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons, which was greatly dependent on loaded miR-21-5p. Finally, we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb, as well as muscle tissue morphology of the hind limbs, were obviously restored. These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p. miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome. This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves, and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.

2.
Zhongguo Zhong Yao Za Zhi ; 49(15): 4167-4177, 2024 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-39307749

RESUMO

This study investigated the role and mechanism of ligustilide(LIG) in attenuating oxygen-glucose deprivation/reoxyge-nation(OGD/R)-induced damage to mouse hippocampal neuron cells(HT22) by inhibiting ferroptosis through mitochondrial ferritin(FtMt). An in vitro model of OGD/R-induced HT22 cell damage was established. HT22 cells were randomly divided into normal group, model group, LIG groups(5, 10, and 20 µmol·L~(-1)), and ferrostatin-1(Fer-1, 2 µmol·L~(-1)) group. Cell viability was mea-sured using the CCK-8 method, and lactate dehydrogenase(LDH) release was measured using an LDH assay kit. Cell morphology was observed under an inverted microscope, and mitochondrial ultrastructure was observed using transmission electron microscopy. Intracellular Fe~(2+) content was detected using a chemiluminescence method. To further investigate the mechanism of FtMt inhibition of ferroptosis, FtMt in HT22 cells was silenced and divided into normal group, model group, LIG group(20 µmol·L~(-1)), si-NC group, si-FtMt group, and si-FtMt+20 µmol·L~(-1) LIG group. Immunofluorescence and Western blot were used to detect FtMt expression. Chemiluminescence was used to measure the content of NADPH/NADP~+, GSH, MDA, and ATP in HT22 cells. The mtROS fluorescence intensity was observed by laser confocal microscopy, and intracellular Fe~(2+) content was measured by flow cytometry. The expression of ferroptosis-related proteins Ferrtin, GPX4, and ACSL4 was detected by Western blot. The results showed that compared with the model group, LIG significantly increased the survival rate of HT22 cells, improved the morphology of damaged HT22 cells and mitochondrial ultrastructure, decreased intracellular Fe~(2+) content, and reduced the expression of the pro-ferroptosis protein ACSL4 while increasing the expression of anti-ferroptosis proteins Ferrtin and GPX4. After silencing FtMt, LIG promoted FtMt expression. Compared with the si-FtMt group, LIG significantly increased the content of NADPH/NADP~+ and GSH, reduced mtROS fluorescence intensity and MDA content, increased ATP activity, decreased intracellular Fe~(2+) content, inhibited the expression of pro-ferroptosis protein ACSL4, and increased the expression of anti-ferroptosis proteins Ferrtin and GPX4. In summary, LIG improved mitochondrial function by upregula-ting FtMt expression to inhibit ferroptosis, thereby alleviating OGD/R-induced damage to HT22 cells.


Assuntos
4-Butirolactona , Ferroptose , Glucose , Animais , Ferroptose/efeitos dos fármacos , Camundongos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/farmacologia , Glucose/metabolismo , Hipocampo/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Oxigênio/metabolismo , Linhagem Celular , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo
3.
Zhongguo Zhong Yao Za Zhi ; 49(17): 4818-4828, 2024 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-39307817

RESUMO

Ginseng Radix et Rhizoma is a unique traditional Chinese herbal medicine in China, with a long medicinal history, unique healthcare effects, and a profound cultural value. The development of the Ginseng Radix et Rhizoma industry has practical and symbolic significance for the traditional Chinese medicine(TCM) industry. Under the new situation, China's Ginseng Radix et Rhizoma industry has faced new development opportunities and also internal and external challenges. It is urgent to deeply analyze the practical problems and explore the solutions. This article systematically reviews the current situation of China's Ginseng Radix et Rhizoma industry from the industrial chain and analyzes the current problems and development trends of this industry, aiming to provide reference and a decision-making basis for the high-quality development of this industry.


Assuntos
Indústria Farmacêutica , Medicamentos de Ervas Chinesas , Panax , Panax/química , China , Medicamentos de Ervas Chinesas/química , Rizoma/química , Medicina Tradicional Chinesa , Humanos , Raízes de Plantas/química , Raízes de Plantas/crescimento & desenvolvimento
4.
Int J Ophthalmol ; 17(9): 1592-1598, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39296552

RESUMO

AIM: To investigate the effect of ß-alanine (BA) on laser-induced choroidal neovascularization (CNV) mice models. METHODS: Laser-induced CNV mice models were established, and BA was administrated for one week and two weeks in advance, separately. Furthermore, retinal pigment epithelium (RPE)-choroid flat mounts were separated, and immunohistochemical staining was performed. The laser-induced CNV lesion areas were measured and compared. In addition, liver and kidney morphologies were observed to identify potential hepatorenal toxicity. RESULTS: Enlarged CNV lesion areas were observed in the BA treated group. No significant differences were observed in the liver and kidney sections between groups. CONCLUSION: BA treatment increase CNV lesion areas, suggesting the detrimental effects of BA as a nutritional supplement in age-related macular degeneration (AMD) population.

5.
Int J Biol Macromol ; : 135944, 2024 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-39317281

RESUMO

Excellent comprehensive performance of hydrogels can be achieved by synergistically combining multiple interaction mechanisms. In this study, a series of hydrogels with rapid gelation and excellent adhesive, mechanical, self-healing, and conductive properties, driven by covalent bonds and multiple reversible interactions, were constructed by mixing acrylic acid (AA), aminated alkaline lignin (AAL), phytic acid (PA), and Fe3+. The rigid skeletons of polyacrylic acid (PAA) and AAL, as well as the metal coordination bonds formed between them and Fe3+, enhance the mechanical properties of the samples. The samples exhibit excellent tensile strength and compressive strength, reaching 73.7 kPa and 4.6 MPa (under a compressive strain of 80 %), respectively, with a tensile strain of 1142 % under the same condition. Adding PA enhances the compliance and adhesion (148.2 kPa for porcine skin) of the gel and endowed it with good flame retardancy. Additionally, the sample maintained its good mechanical properties and conductivity even after five cutting-healing cycles. Good durability, robust adhesion, and high electrical conductivity of the sample render it a promising strain sensor for electronic devices. This work provides a design strategy for preparing hydrogels with superior adhesion and good comprehensive performance.

7.
Chin J Integr Med ; 2024 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-39305458

RESUMO

OBJECTIVE: To assess the cardioprotective effect and impact of Qishen Granules (QSG) on different ischemic areas of the myocardium in heart failure (HF) rats by evaluating its metabolic pattern, substrate utilization, and mechanistic modulation. METHODS: In vivo, echocardiography and histology were used to assess rat cardiac function; positron emission tomography was performed to assess the abundance of glucose metabolism in the ischemic border and remote areas of the heart; fatty acid metabolism and ATP production levels were assessed by hematologic and biochemical analyses. The above experiments evaluated the cardioprotective effect of QSG on left anterior descending ligation-induced HF in rats and the mode of energy metabolism modulation. In vitro, a hypoxia-induced H9C2 model was established, mitochondrial damage was evaluated by flow cytometry, and nuclear translocation of hypoxia-inducible factor-1 α (HIF-1 α) was observed by immunofluorescence to assess the mechanism of energy metabolism regulation by QSG in hypoxic and normoxia conditions. RESULTS: QSG regulated the pattern of glucose and fatty acid metabolism in the border and remote areas of the heart via the HIF-1 α pathway, and improved cardiac function in HF rats. Specifically, QSG promoted HIF-1 α expression and entry into the nucleus at high levels of hypoxia (P<0.05), thereby promoting increased compensatory glucose metabolism; while reducing nuclear accumulation of HIF-1 α at relatively low levels of hypoxia (P<0.05), promoting the increased lipid metabolism. CONCLUSIONS: QSG regulates the protein stability of HIF-1 α, thereby coordinating energy supply balance between the ischemic border and remote areas of the myocardium. This alleviates the energy metabolism disorder caused by ischemic injury.

8.
Angew Chem Int Ed Engl ; : e202413296, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39320168

RESUMO

Fundamental understanding of initial evolutions of molecules in the universe is of great interest and importance. CH4 is one of the abundant simple molecules in the universe. Herein we report γ-ray, high-energy photons commonly existing in cosmic rays and unstable isotope decay, as an external energy to efficiently drives aqueous-phase CH4 conversions to various products with the presence of oxygen at room temperature. Glycine also forms with an additional introduction of ammonia. Both CH4 conversions and product distributions are modified by solid granules, and a CH3COOH selectivity as high as 82% is obtained when SiO2 is added. Our results point to γ-ray driven aqueous-phase CH4 conversions as a likely formation network of initial complex organic compounds in the universe and offer an alternative strategy for efficiently utilizing CH4 as the carbon source to produce value-added products at mild conditions, a long-standing challenging task in heterogeneous catalysis.

9.
Artigo em Inglês | MEDLINE | ID: mdl-39320554

RESUMO

Human reproduction is a complex process involving gamete maturation, fertilization, embryo cleavage and development, blastocyst formation, implantation, and live birth. If any of these processes are abnormal or arrest, reproductive failure will occur. Infertility is a state of reproductive dysfunction caused by various factors. Advances in molecular genetics, including cell and molecular genetics, and high-throughput sequencing technologies, have found that genetic factors are important causes of infertility. Genetic variants have been identified in infertile women or men and can cause gamete maturation arrest, poor quality gametes, fertilization failure, and embryonic developmental arrest during assisted reproduction technology (ART), and thus reduce the clinical success rates of ART. This article reviews clinical studies on repeated in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) failures caused by ovarian dysfunction, oocyte maturation defects, oocyte abnormalities, fertilization disorders, and preimplantation embryonic development arrest due to female genetic etiology, the accumulation of pathogenic genes and gene pathogenic loci, and the functional mechanism and clinical significance of pathogenic genes in gametogenesis and early embryonic development.

10.
Pharmacol Res ; 209: 107420, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39293586

RESUMO

Endometrial cancer (EC) is one of the most common gynecologic malignancies, which lacking effective drugs for intractable conditions or patients unsuitable for surgeries. Recently, the patient-derived organoids (PDOs) are found feasible for cancer research and drug discoveries. Here, we have successfully established a panel of PDOs from EC and conducted drug repurposing screening and mechanism analysis for cancer treatment. We confirmed that the regulatory ß subunit of methionine adenosyltransferase (MAT2B) is highly correlated with malignant progression in endometrial cancer. Through drug screening on PDOs, we identify JX24120, chlorpromazine derivative, as a specific inhibitor for MAT2B, which directly binds to MAT2B (Kd = 4.724 µM) and inhibits the viability of EC PDOs and canonical cell lines. Correspondingly, gene editing assessment demonstrates that JX24120 suppresses tumor growth depending on the presence of MAT2B in vivo and in vitro. Mechanistically, JX24120 induces inhibition of S-adenosylmethionine (SAMe) synthesis, leading to suppressed mTORC1 signaling, abnormal energy metabolism and protein synthesis, and eventually apoptosis. Taken together, our study offers a novel approach for drug discovery and efficacy assessment by using the PDOs models. These findings suggest that JX24120 may be a potent MAT2B inhibitor and will hopefully serve as a prospective compound for endometrial cancer therapy.

11.
Nutr Metab (Lond) ; 21(1): 75, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39304912

RESUMO

BACKGROUND: 3-Hydroxybutyrate, also called ß-hydroxybutyrate, is a significant constituent of ketone bodies. Previous observational and experimental studies have suggested that ketogenic diet, especially 3-hydroxybutyrate, may have a protective effect against cardiovascular disease. However, the relationship between ketone bodies, especially 3-hydroxybutyrate, and aortic dissection remains uncertain. MATERIALS AND METHODS: Publicly accessible data from genome-wide association study (GWAS) was utilized to obtain information on ketone bodies, including 3-hydroxybutyrate, acetoacetate and acetone as exposure respectively, while GWAS data on aortic dissection was used as outcome. Subsequently, two-sample Mendelian randomization (MR) analysis was conducted to examine the potential relationship between ketone bodies and aortic dissection. Then, reverse and multivariate Mendelian randomization analyses were performed. Additionally, sensitivity tests were conducted to assess the robustness of MR study. RESULTS: The inverse-variance weighted (IVW) method of Mendelian randomization analysis of gene prediction observed a negative correlation between 3-hydroxybutyrate and risk of aortic dissection (OR 0.147, 95% CI 0.053-0.410). Furthermore, consistent findings were obtained through the implementation of the weighted median, simple mode, Mendelian randomization-Egger (MR-Egger), and weighted mode methods. After adjusting acetoacetate (OR 0.143, 95% CI 0.023-0.900) or acetone (OR 0.100, 95% CI 0.025-0.398), MR analysis of gene prediction still observed a negative correlation between 3-hydroxybutyrate and risk of aortic dissection. No indications of heterogeneity or pleiotropy among the SNPs were detected. CONCLUSION: The findings from the MR analysis demonstrated that genetically predicted 3-hydroxybutyrate exhibits a protective effect against aortic dissection.

12.
Eur J Med Chem ; 279: 116885, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39307103

RESUMO

The persistent mutation of the novel coronavirus presents a continual threat of infections and associated illnesses. While considerable research efforts have concentrated on the functional proteins of SARS-CoV-2 in the development of anti-COVID-19 therapeutics, the structural proteins, particularly the N protein, have received comparatively less attention. This study focuses on the N protein, a critical structural component of the virus, and employs advanced deep learning models, including EMPIRE and DeepFrag, to optimize the structures of phenanthridine-based compounds. More than 10,000 small molecules, derived through deep learning, underwent high-throughput virtual screening, resulting in the synthesis of 44 compounds. Compound 38 showed a binding potential energy of -8.2 kcal/mol in molecular docking. Surface Plasmon Resonance (SPR) and Microscale Thermophoresis (MST) validation yielded dissociation constants of 353 nM and 726 nM, confirming strong binding to the N protein. Compound 38 demonstrated antiviral activity in vitro and exhibited anti-COVID-19 effects by interfering with the binding of N proteins to RNA. This research underscores the potential of targeting the SARS-CoV-2 N protein for therapeutic intervention and illustrates the efficacy of deep learning model in the design of lead compounds. The application of these deep learning models represents a promising approach for accelerating the discovery and development of antiviral agents.

13.
Am J Clin Exp Immunol ; 13(4): 195-201, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39310122

RESUMO

OBJECTIVE: To evaluate the clinical effectiveness of surface electromyography combined with a spine 3D data system. METHODS: 10 idiopathic scoliosis patients (age: 12.90±3.67 years, height: 155.90±20.07 cm, weight: 48.00±12.86 kg, 6 major thoracic lateral bends and 4 lumbar bends) who were selected to attend the outpatient clinic of Ruijin Rehabilitation Hospital, First diagnosed as scoliosis by imaging examination (EOS system), evaluation by using the surface electromyography monitoring system, the radiation-free 3D spine data acquisition and analysis system, the surface electromyography of the paravertebral muscles (root mean square value (RMS) of the resting standing and action position of the spine) and the Cobb angle of scoliosis were recorded. RESULTS: The RMS of the convex side was larger than that of the concave side in the two postures (P<0.05), and The RMS value of bilateral action position was significantly higher than that of rest position (P<0.05). There was no correlation between RMS ratio and Cobb angle in two positions of thoracic scoliosis (P>0.05). There was a significant correlation between the RMS ratio at rest position of lumbar scoliosis and Cobb angle. At rest, the RMS value of convex side was significantly correlated with the Cobb angle measured by the EOS system and the 3D data system (P<0.05, of which P<0.01). The Cobb angle measured by 3D data system and the EOS system was significantly correlated (P<0.01). CONCLUSION: Surface EMG can be used to evaluate the motor function of paravertebral muscles on both sides of scoliosis patients. The new 3D data system has high accuracy in evaluating scoliosis. The combination of the two can dynamically evaluate scoliosis, which is more clinically effective.

14.
Front Cell Dev Biol ; 12: 1424395, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39291267

RESUMO

Background: Cardiac lipid metabolism reprogramming is recognized as a critical pathological factor in the progression of chronic heart failure (CHF). The therapeutic potential of digilanid C and electroacupuncture stimulation (ES) in enhancing lipid metabolism and cardiac function has been established. However, the optimal synergistic regulatory strategies of these interventions on cardiac lipid metabolism have yet to be elucidated. Methods: This study aimed to comprehensively evaluate the impact of a digilanid C-ES combination on cardiac steatosis remodeling in CHF. Assessments were conducted across various dimensions, including myocardial oxygen consumption, mitochondrial function, and lipid metabolism. Additionally, we sought to uncover the underlying neuromolecular mechanisms. Results: Our findings, at both molecular and morphological levels, indicated that the synergistic application of digilanid C and ES significantly inhibited myocardial fibrosis and steatosis. This combination therapy facilitated the repair of cardiac neuro-vascular uncoupling and induced a reprogramming of lipid metabolism. Notably, the digilanid C-ES combination ameliorated cardiomyocyte apoptosis and enhanced mitochondrial biogenesis in CHF, leading to a restructured energy supply pattern. Cardiac immunofluorescence analyses revealed the aggregation of cardiac glial cells (CGCs) at sites of abnormal neurovascular coupling, a response to cardiac lipid degeneration. This was accompanied by a marked reduction in the abnormally elevated expression of interleukin 6 (IL-6) and glutamatergic signaling, which correlated with the severity of cardiac steatosis and the aberrant activation of CGCs. The combined therapy was found to activate the Janus kinase 1 (JAK1)/signal transducer and activator of transcription 3 (STAT3) pathway, effectively attenuated lipid accumulation and over-recruitment of CGCs and deprivation of glutamatergic nerves. Conclusion: These findings underscore the potential of digilanid C and ES combination therapy as a novel approach to modulate the complex interplay between neurovascular dynamics and metabolic dysregulation in CHF.

15.
Environ Sci Technol ; 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39292548

RESUMO

The escalating concern of perfluoroalkyl and polyfluoroalkyl substances (PFAS), particularly at contaminated sites, has prompted extensive investigations. In this study, samples of multimedia including air, rhizosphere soil, and tissues of wheat at various growing stages were collected near a mega fluorochemical industrial park in China. Perfluorooctanoic acid (PFOA) was predominant in both air and soil with a strong correlation, highlighting air deposition as an important source in the terrestrial system. PFAS concentrations in wheat decreased in the stem and ear but increased in the leaves as wheat matured. Specifically, perfluorobutanoic acid (PFBA) dominated in the aboveground tissues in the full-life-cycle, except that PFOA surpassed and became predominant in leaves during the filling and maturing stages, hinting at an airborne source. For all PFAS, both bioaccumulation factors and translocation factors (TFs) were inversely correlated with the carbon chain length during the full-life-cycle. The obtained TF values were considerably higher than those obtained from ambient sites reported previously, further suggesting an unneglectable foliar uptake from air, which was estimated to be 25% for PFOA. Moreover, spray irrigation remarkably enhanced the absorption of PFAS in wheat via foliar uptake relative to flood irrigation. The estimated daily intake of PFBA via wheat consumption and air inhalation was 0.50 µg/kg/day for local residents, at least one magnitude higher than the corresponding threshold, suggesting an alarmingly high exposure risk.

16.
Phys Chem Chem Phys ; 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39291756

RESUMO

Superparamagnetic iron oxide nanoparticles (SPIONs) are a promising tool for biomedical applications, including drug delivery, imaging, and magnetic hyperthermia. However, their tendency to agglomerate limits their performance efficiency. To overcome this limitation, a coating can be applied during or after synthesis. This work investigates the effect of three biocompatible coatings, namely sodium citrate, (3-aminopropyl)triethoxysilane (APTES), and dextran, on controlling the agglomeration of iron oxide nanoparticles. Various experimental techniques were used to characterize the structural and magnetic properties of the coated nanoparticles, including cryogenic transmission electron microscopy (cryo-TEM), magnetometry, Mössbauer spectroscopy, and small-angle X-ray and neutron scattering. The results indicate that the coatings effectively stabilize the nanoparticles, leading to clusters of different sizes that modify their magnetic behaviour due to magnetic inter-particle interactions. The oxidation kinetics of the nanoparticles prepared with the various coating materials were investigated to characterize their oxidation behaviour and stability over time. This research provides valuable insights into the design of an optimized nanoparticle functionalization strategy for biomedical applications.

18.
Nat Protoc ; 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39237831

RESUMO

One of the foremost challenges in nanobiotechnology is obtaining direct evidence of nanoparticles' absorption and internalization in plants. Although confocal laser scanning microscopy (CLSM) or transmission electron microscopy (TEM) are currently the most commonly used tools to characterize nanoparticles in plants, subjectivity of researchers, incorrect sample handling, inevitable fluorescence leakage and limitations of imaging instruments lead to false positives and non-reproducibility of experimental results. This protocol provides an easy-to-operate dual-step method, combining CLSM for macroscopic tissue examination and TEM for cellular-level analysis, to effectively trace single particles in plant roots with accuracy and precision. In addition, we also provide detailed methods for processing plant materials before imaging, including cleaning, and staining, to maximize the accuracy and reliability of imaging. This protocol involves currently commonly used nanomaterial types, such as metal-based and doped carbon-based materials, and enables accurate localization of nanoparticles with different sizes at the cell level in Arabidopsis thaliana root samples either through contrast or element mapping analysis. It serves as a valuable reference and benchmark for scholars in plant science, chemistry and environmental studies to understand the interaction between plant roots and nanomaterials and to detect the distribution of nanomaterials in plants. Excluding plant culture time, the protocol can be completed in 4-5 d.

19.
Chemistry ; : e202402931, 2024 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-39243222

RESUMO

Two fenestrindane-based porous nanographenes containing four polyaromatic macrocycles in a highly twisted, basically S4-symmetric conformation were synthesized and characterized by NMR spectroscopy and mass spectrometry. Stepwise π-extension at the periphery of the fenestrindane core by a sequence of eightfold Suzuki-Miyaura cross-coupling, fourfold Scholl cyclodehydrogenation and another eightfold Suzuki-Miyaura reaction affords the porous nanographene precursors in good yields. In the last step, fourfold intramolecular Yamamoto coupling generates the porous nanographenes in 17-18% yield. Their optical and electronic properties were studied by UV/Vis and fluorescence spectroscopy and cyclic voltammetry. DFT calculations revealed structural details of the macrocycles. The surprisingly weak binding of these porous structures with chloride ions (K ≈ 10 M-1) is attributed to their highly twisted conformation. The title compounds represent the first porous nanographenes based on the [5.5.5.5]fenestrane motif and, at the same time, they consist of a fenestrane-like polyarylene network.

20.
Ying Yong Sheng Tai Xue Bao ; 35(7): 1907-1914, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39233420

RESUMO

Real-time assessment of ecological environment quality in arid and semi-arid regions is crucial for the sustainable development of ecological environments in China. In this study, we constructed a topsoil remote sensing ecological index (TRSEI) by coupling five indicators, greenness, wetness, dryness, topsoil grain size, and heat, with the Google Earth Engine (GEE). With the index, we evaluated the ecological environment quality of Wuchuan County from 1990 to 2020, and examined the spatio-temporal variations of ecological environment quality and its driving factors by using univariate linear regression, multiple regression residual analysis, and Hurst index. Results showed that the first principal component of the TRSEI in the study area contributed over 70%, with a mean eigenvalue of 0.148, indicating the effective integration of various ecological indicators by TRSEI. The topsoil grain size index was essential for the assessment of ecological environment quality in arid and semi-arid regions. From 1990 to 2020, the fluctuation range of TRSEI in the study area was between 0.289 and 0.458, showing an overall slight deterioration trend. The ecological environment quality of cropland and de-farming region had improved, with the improved area accounting for 47.9% of the total area. The grassland, barren land, and construction land areas had deteriorated, with the deteriorated area accounting for 52.1% of the total area. In the future, 36.9% of the regions would experience continuous improvement in ecological environment quality, while 41.4% might continue to dete-riorate. Human activities were the primary driving factor for the changes in ecological environment quality in arid and semi-arid regions, accounting for 88.6% of the total area. Climate change also had a significant impact, accounting for 11.4% of the total area. The TRSEI could effectively assess the ecological environment quality of arid and semi-arid regions, providing a scientific basis for ecological conservation and construction in these areas.


Assuntos
Clima Desértico , Ecossistema , Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , China , Tecnologia de Sensoriamento Remoto/métodos , Monitoramento Ambiental/métodos , Conservação dos Recursos Naturais/métodos , Ecologia/métodos
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