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2.
Angew Chem Int Ed Engl ; : e202405676, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38606914

RESUMEN

Metal-organic framework (MOF) membranes with rich functionality and tunable pore system are promising for precise molecular separation; however, it remains a challenge to develop defect-free high-connectivity MOF membrane with high water stability owing to uncontrollable nucleation and growth rate during fabrication process. Herein, we report on a confined-coordination induced intergrowth strategy to fabricate lattice-defect-free Zr-MOF membrane towards precise molecular separation. The confined-coordination space properties (size and shape) and environment (water or DMF) were regulated to slow down the coordination reaction rate via controlling the counter-diffusion of MOF precursors (metal cluster and ligand), thereby inter-growing MOF crystals into integrated membrane. The resulting Zr-MOF membrane with angstrom-sized lattice apertures exhibits excellent separation performance both for gas separation and water desalination process. It was achieved H2 permeance of ~1200 GPU and H2/CO2 selectivity of ~67; water permeance of ~8 L·m-2·h-1·bar-1 and MgCl2 rejection of ~95%, which are one to two orders of magnitude higher than those of state-of-the-art membranes. The molecular transport mechanism related to size-sieving effect and transition energy barrier differential of molecules and ions was revealed by density functional theory calculations. Our work provides a facile approach and fundamental insights towards developing precise molecular sieving membranes.

3.
BMC Chem ; 18(1): 46, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38449054

RESUMEN

Pest disasters which occurs on crops is a serious problem that not only cause crop yield loss or even crop failure but can also spread a number of plant diseases.Sulfonate derivatives have been widely used in insecticide and fungicide research in recent years. On this basis, a series of sulfonate derivatives bearing an amide unit are synthesized and the biological activities are evaluated. The bioassay results showed that compounds A8, A13, A16, B1, B3, B4, B5, B10, B12 - 20, C3, C5, C9, C10, C14, C15, C17 and C19 showed 100% activity at a concentration of 500 µg/mL against the Plutella xylostella (P. xylostella). Among them, B15 which contains a thiadiazole sulfonate structure still shows 100% activity at 50 µg/mL concentration against P. xylostella and had the lowest median lethal concentration (LC50) (7.61 µg/mL) among the target compounds. Further mechanism studies are conducted on compounds with better insecticidal activity. Molecular docking results shows that B15 formed hydrophobic interactions π-π and hydrogen bonds with the indole ring of Trp532 and the carboxyl group of Asp384, respectively, with similar interaction distances or bond lengths as those of diflubenzuron. Moreover, chitinase inhibition assays are performed to further demonstrate its mode of action. In addition, the anti-bacterial activity of the series of compounds is also tested and the results showed that the series of compounds has moderate biological activity against Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), with inhibition rates of 91%, 92% and 92%, 88% at the concentration of 100 µg/mL, respectively. Our study indicates that B15 can be used as a novel insecticide for crop protection.

4.
Chem Commun (Camb) ; 60(28): 3858-3861, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38497365

RESUMEN

Herein, we describe a copper-catalyzed intramolecular dearomative amination of indoles via a formal aza-Wacker reaction. This protocol provides an efficient method to access aza-polycyclic indoline molecules bearing exocyclic CC bonds in moderate to excellent yields in the presence of molecular oxygen as an oxidant. It is worth noting that indolin-3-ones are achieved when employing C3-non-substituted indoles as substrates.

5.
Chem Biodivers ; : e202400408, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38441384

RESUMEN

To develop novel bacterial biofilm inhibiting agents, a series of 1,3,4-thiadiazole derivatives containing sulfonylpiperazine structures were designed, synthesized, and characterized using 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR), and high-resolution mass spectrometry. Meanwhile, their biological activities were evaluated, and the ensuing structure-activity relationships were discussed. The bioassay results showed the substantial antimicrobial efficacy exhibited by most of the compounds. Among them, compound A24 demonstrated a strong efficacy with an EC50 value of 7.8 µg/mL in vitro against the Xanthomonas oryzae pv. oryzicola (Xoc) pathogen, surpassing commercial agents thiodiazole copper (31.8 µg/mL) and bismerthiazol (43.3 µg/mL). Mechanistic investigations into its anti-Xoc properties revealed that compound A24 operates by increasing the permeability of bacterial cell membranes, inhibiting biofilm formation and cell motility, and inducing morphological changes in bacterial cells. Importantly, in vivo tests showed its excellent protective and curative effects on rice bacterial leaf streak. Besides, molecular docking showed that the hydrophobic effect and hydrogen-bond interactions are key factors between the binding of A24 and AvrRxo1-ORF1. Therefore, these results suggest the utilization of 1,3,4-thiadiazole derivatives containing sulfonylpiperazine structures as a bacterial biofilm inhibiting agent, warranting further exploration in the realm of agrochemical development.

6.
Org Lett ; 26(12): 2359-2364, 2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38488270

RESUMEN

A palladium-catalyzed dearomative diarylation of C2-deuterated or C2-nonsubstituted indoles through domino Heck/Suzuki coupling is established. Relying on electron-deficient phosphite ligand, side reactions including intermolecular Suzuki coupling and intramolecular C-D/H arylation are inhibited and a wide range of 2,3-diarylated indolines bearing vicinal tertiary stereocenters including deuterated ones are afforded in moderate to excellent yields (up to 94%) and excellent diastereoselectivities (>20:1). The catalyst loading can be lowered to 0.02 mol % at elevated temperature.

7.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 46(1): 25-32, 2024 Feb.
Artículo en Chino | MEDLINE | ID: mdl-38433627

RESUMEN

Objective To analyze the trends of disease burden of cervical cancer,uterine cancer,and ovarian cancer among Chinese women from 1990 to 2019,and to provide a basis for formulating precise prevention and control measures in China. Methods The global disease burden data in 2019 were used to describe the changes in indicators such as incidence,mortality,years of life lost due to premature mortality(YLL),years lived with disability(YLD),and disability-adjusted life year(DALY) of cervical,uterine,and ovarian cancers in China from 1990 to 2019.Furthermore,the Bayesian age-period-cohort model was adopted to predict the incidence and mortality of the cancers from 2020 to 2030. Results From 1990 to 2019,the incidence rates and mortality of cervical,uterine,and ovarian cancers in Chinese women showed an upward trend,and the age-standardized incidence rate of ovarian cancer increased the most(0.78%).In 2019,the incidence of cervical cancer and uterine cancer concentrated in the women of 55-59 years old,and ovarian cancer mainly occurred in the women of 70-74 years old.The DALY,YLL,and YLD of cervical,uterine,and ovarian cancers all presented varying degrees of growth at all ages.The Bayesian age-period-cohort model predicted that from 2020 to 2030,the incidence and mortality of cervical cancer in China showed a decreasing trend,while those of uterine cancer and ovarian cancer showed an increasing trend.There was no significant change in the age with high incidence of the three cancers. Conclusions From 1990 to 2019,the overall disease burden of cervical,uterine,and ovarian cancers in China increased,while the disease burden of cervical cancer decreased after 2020.It is recommended that the efforts should be doubled for the prevention and control of cervical,uterine,and ovarian cancers.


Asunto(s)
Neoplasias Ováricas , Neoplasias del Cuello Uterino , Femenino , Humanos , Persona de Mediana Edad , Anciano , Neoplasias del Cuello Uterino/epidemiología , Teorema de Bayes , Neoplasias Ováricas/epidemiología , Costo de Enfermedad , Genitales , China/epidemiología
8.
BMC Geriatr ; 24(1): 225, 2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38439007

RESUMEN

OBJECTIVE: The aim of present study was to evaluate the combined effect of hypertension and activities of daily living (ADL)/instrumental activities of daily living (IADL) with the risk of CVD, stroke and cardiac events. METHODS: A total of 14,083 participants aged 45 years or older from the China Health and Retirement longitudinal study were included in current study. Participants were divided into 4 groups according to hypertension and ADL/IADL status. Cox proportional hazards regression model was used to explore the associations between hypertension, ADL/IADL and new-onset CVD, stroke and cardiac events. RESULTS: During the 7-year follow-up, a total of 2,324 respondents experienced CVD (including 783 stroke and 1,740 cardiac events). Individuals with limitations in ADL alone, or with hypertension alone, or with both limitations in ADL and hypertension were associated with increased risk of CVD, with the adjusted hazard ratios (95% confidence intervals) were 1.17(1.00-1.35), 1.36(1.24-1.49) and 1.44(1.23-1.68), respectively. Those with limitations in ADL and hypertension also had higher risk of stroke (hazard ratios = 1.64; 1.26-2.14) and cardiac events (hazard ratios = 1.37; 1.14-1.64). Similarly, individuals with both limitations in IADL and hypertension were associated with increased risk of CVD (hazard ratios = 1.34; 1.15-1.57), stroke (hazard ratios = 1.50; 1.17-1.95) and cardiac events (hazard ratios = 1.27; 1.06-1.53). CONCLUSION: Hypertension and limitations in ADL/IADL jointly increased the risk of CVD, stroke and cardiac events.


Asunto(s)
Enfermedades Cardiovasculares , Hipertensión , Accidente Cerebrovascular , Humanos , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/epidemiología , Actividades Cotidianas , Estudios Longitudinales , Hipertensión/diagnóstico , Hipertensión/epidemiología , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/epidemiología
9.
Huan Jing Ke Xue ; 45(3): 1243-1253, 2024 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-38471841

RESUMEN

Based on the whole life cycle perspective, the carbon emissions of the provincial construction industry in China from 2011 to 2019 were calculated from the production, construction, operation, and demolition stages of building materials. A spatial correlation network matrix of the carbon emissions in the construction industry was constructed by using the modified gravity model, and the structural characteristics of the correlation network were described by introducing social network analysis. Through the quadratic assignment program, the spatial correlation matrix of carbon emissions in the construction industry and its influencing factors were regressed and analyzed. The conclusions were as follows:① the spatial correlation network of carbon emissions in China's construction industry clearly existed. The network density and network correlation numbers were gradually rising, and the network tightness and stability were gradually improving. ② Shanghai, Tianjin, Beijing, and Jiangsu had a higher degree centrality and closeness centrality, which are the core and dominant positions of the spatial correlation network of carbon emissions in the construction industry. Zhejiang replaced Shanghai in the top four from 2013 to 2018, and the betweenness centrality of each province had unbalanced characteristics. ③ Beijing, Tianjin, Jiangsu, Inner Mongolia, Shanghai, and Shandong were "net beneficiaries" blocks, receiving the carbon emissions from other regions. Four provinces, Guangdong, Chongqing, Fujian, and Shandong, belonged to the "broker" sector, achieving a dynamic balance between the production and consumption sides of building carbon emissions. The remaining 20 provinces played a "net spillovers" role, actively sending carbon emissions from the construction industry to other provinces. The correlation between blocks was much greater than the correlation relationship within the blocks. ④ Industrial structure, urban population, spatial adjacency, consumption level, and construction industry process structure had a significant influence on the spatial correlation of carbon emissions in the construction industry. The greater the inter-provincial differences in industrial structure, urban population, spatial adjacency, and consumption level, the greater the similarity of inter-provincial construction industry process structure, and the stronger the spatial correlation and spatial spillover of the construction industry carbon emissions. Finally, according to the evolution characteristics and influencing factors of the spatial correlation network of building carbon emissions, relevant countermeasures and suggestions were provided for the collaborative carbon reduction development of the construction industry region.

10.
Clin Nutr ; 43(3): 796-802, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38350287

RESUMEN

BACKGROUND: Previous studies have demonstrated that sarcopenia was associated with a high risk of cardiovascular disease (CVD). Nevertheless, little is known about the associations between sarcopenic obesity/possibly sarcopenic obesity and the risk of CVD among senior and middle-aged adults. METHODS: Utilizing the nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS), a sum of 7703 individuals aged at least 45 years were divided into four groups. The effects of sarcopenic obesity and possibly sarcopenic obesity on CVD were calculated using Cox proportional hazards regression models. Non-sarcopenic participants with optimal body mass index (BMI) or waist circumference (WC) served as a control group. RESULTS: Sarcopenic obesity were related to increased risks of CVD (HR = 1.39; 95% CI = 1.16-1.67), heart disease (HR = 1.36; 95% CI = 1.10-1.67) and stroke (HR = 1.40; 95% CI = 1.02-1.92) compared with the optimal reference group. Similarly, the risk of CVD, heart disease and stroke increased by 0.34, 0.28 and 0.39 times in obese people with possible sarcopenia compared to the control group. Sensitivity analysis identified similar results to those described above. Patients with sarcopenia and a BMI ≥28.0 kg/m2 had a 1.47- and 1.48-fold risk of developing CVD and heart disease than controls. CONCLUSION: Sarcopenic obesity and possibly sarcopenic obesity are positively associated with the development of CVD. The middle-aged and elderly population should prevent obesity and maintain muscle mass through some interventions such as weight control and moderate exercise, which may reduce the CVD risk.


Asunto(s)
Enfermedades Cardiovasculares , Cardiopatías , Sarcopenia , Accidente Cerebrovascular , Persona de Mediana Edad , Humanos , Anciano , Enfermedades Cardiovasculares/epidemiología , Sarcopenia/complicaciones , Sarcopenia/epidemiología , Estudios de Cohortes , Estudios Longitudinales , Jubilación , China/epidemiología , Obesidad/complicaciones , Obesidad/epidemiología
11.
Laryngoscope Investig Otolaryngol ; 9(1): e1205, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38362199

RESUMEN

Objective: To assess the extent of recurrent laryngeal nerve (RLN) and superior laryngeal nerve (SLN) damage in patients with idiopathic vocal cord paralysis (IVCP) exhibiting different paralytic sides. Methods: A total of 84 IVCP cases were evaluated using stroboscopic laryngoscopy, voice analysis, and laryngeal electromyography (LEMG). The results were compared between patients with left-sided paralysis and right-sided paralysis based on different disease courses (less than or more than 3 months). Results: Initially, the average age and disease progression of IVCP patients were found to be similar regardless of the side of paralysis (p > .05). Additionally, there were no significant variations in voice indicators, such as MPT, DSI, and VHI, between IVCP patients with left and right vocal cord paralysis (p > .05). Furthermore, no disparities were detected in the latencies and amplitudes of the paralyzed RLN and SLN, as well as the durations and amplitudes of the action potentials in the paralyzed TM and PCM, among IVCP patients with left and right vocal cord paralysis (p > .05). Notably, the amplitudes of the left paralytic CM were significantly lower than those of the right paralytic CM (0.45 vs. 0.53, Z = -2.013, p = .044). In addition, no disparities were observed in APDs and amplitudes between the ipsilateral PCM and TM, either for patients with left or right vocal fold paralysis (p > .05). Finally, all the IVCP patients were subdivided into two subgroups according to different disease course (less than or more than 3 months), and in each subgroup, the comparison of voice indicators and LEMG results in IVCP patients with left or right vocal fold paralysis were similar with the above findings (p > .05). Conclusion: Overall, the degree of RLN and SLN damage appeared to be similar in IVCP patients with left and right vocal cord paralysis, provided that the disease course was comparable. Level of Evidence: 4.

12.
ACS Appl Mater Interfaces ; 16(7): 8679-8687, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38324753

RESUMEN

Heterostructure engineering and oxygen vacancy engineering are the most promising modification strategies to reinforce the Zn2+ ion storage of vanadium oxides. Herein, a rare mixed-dimensional material (VOx), composed of V2O5 (2D), V3O7 (3D), and V6O13 (3D) heterostructures, rich in oxygen vacancies, was synthesized via thermal decomposition of layered ammonium vanadate. The VOx cathode provides an exceptional discharge capacity (411 mA h g-1 at 0.1 A g-1) and superior cycling stability (the capacity retention remains close to 100% after 800 cycles at 2 A g-1) for aqueous zinc-ion batteries (AZIBs). Ex situ characterizations confirm that the byproduct Zn3V2O7(OH)2·nH2O is generated/decomposed during discharge/charge processes. Furthermore, VOx demonstrates reversible intercalation/deintercalation of H+/Zn2+ ions, enabling efficient energy storage. Remarkably, a reversible crystal-to-amorphous transformation in the V2O5 phase of VOx during charge-discharge was observed. This investigation reveals that mixed-dimensional heterostructured vanadium oxide, with abundant oxygen vacancies, serves as a highly promising electrode material for AZIBs, further advancing the comprehension of the storage mechanism within vanadium-based cathode materials.

13.
Cell Signal ; 115: 111038, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38195035

RESUMEN

N6-methyladenosine (m6A), the most prevalent internal modification in mRNA, is related to the pathogenesis of osteoporosis (OP). Although methyltransferase Like-3 (METTL3), an m6A transferase, has been shown to mitigate OP progression, the mechanisms of METTL3-mediated m6A modification in osteoblast function remain unclear. Here, fluid shear stress (FSS) induced osteoblast proliferation and differentiation, resulting in elevated levels of METTL3 expression and m6A modification. Through Methylated RNA Immunoprecipitation Sequencing (MeRIP-seq) and Transcriptomic RNA Sequencing (RNA-seq), SRY (Sex Determining Region Y)-box 4 (SOX4) was screened as a target of METTL3, whose m6A-modified coding sequence (CDS) regions exhibited binding affinity towards METTL3. Further functional experiments demonstrated that knockdown of METTL3 and SOX4 hampered osteogenesis, and METTL3 knockdown compromised SOX4 mRNA stability. Via RNA immunoprecipitation (RIP) assays, we further confirmed the direct interaction between METTL3 and SOX4. YTH N6-Methyladenosine RNA Binding Protein 3 (YTHDF3) was identified as the m6A reader responsible for modulating SOX4 mRNA and protein levels by affecting its degradation. Furthermore, in vivo experiments demonstrated that bone loss in an ovariectomized (OVX) mouse model was reversed through the overexpression of SOX4 mediated by adeno-associated virus serotype 2 (AAV2). In conclusion, our research demonstrates that METTL3-mediated m6A modification of SOX4 plays a crucial role in regulating osteoblast proliferation and differentiation through its recognition by YTHDF3. Our research confirms METTL3-m6A-SOX4-YTHDF3 as an essential axis and potential mechanism in OP.


Asunto(s)
Metiltransferasas , Osteoblastos , Animales , Ratones , Proliferación Celular , Metiltransferasas/metabolismo , Osteoblastos/metabolismo , ARN , ARN Mensajero/metabolismo
15.
Comput Biol Med ; 169: 107952, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38194779

RESUMEN

Diabetes, a common chronic disease worldwide, can induce vascular complications, such as coronary heart disease (CHD), which is also one of the main causes of human death. It is of great significance to study the factors of diabetic patients complicated with CHD for understanding the occurrence of diabetes/CHD comorbidity. In this study, by analyzing the risk of CHD in more than 300,000 diabetes patients in southwest China, an artificial intelligence (AI) model was proposed to predict the risk of diabetes/CHD comorbidity. Firstly, we statistically analyzed the distribution of four types of features (basic demographic information, laboratory indicators, medical examination, and questionnaire) in comorbidities, and evaluated the predictive performance of three traditional machine learning methods (eXtreme Gradient Boosting, Random Forest, and Logistic regression). In addition, we have identified nine important features, including age, WHtR, BMI, stroke, smoking, chronic lung disease, drinking and MSP. Finally, the model produced an area under the receiver operating characteristic curve (AUC) of 0.701 on the test samples. These findings can provide personalized guidance for early CHD warning for diabetic populations.


Asunto(s)
Enfermedad Coronaria , Diabetes Mellitus , Humanos , Inteligencia Artificial , Diabetes Mellitus/diagnóstico , Enfermedad Coronaria/epidemiología , Enfermedad Coronaria/etiología , China/epidemiología , Aprendizaje Automático
16.
J Chem Inf Model ; 64(2): 359-377, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38164000

RESUMEN

p-Sulfonatocalix[n]arenes (SCnA) have demonstrated great potential for drug encapsulation through host-guest complexation to improve solubility, stability, and bioavailability. In this study, the solubilization effect of SCnA (n = 4, 6, 8) on 95 active compounds derived from traditional Chinese medicine (TCM) was investigated. Based on the significant solubilization effect on alkaloids, SC6A/SC8A and 76 alkaloids were selected as the host and guest, respectively, to determine the binding constant by competitive fluorescence titration. LASSO regression was adopted to investigate the mechanism of the complex of SCnA with alkaloids. The binding constant of alkaloids-SC6A and alkaloids-SC8A was related to the alkaloid alkalinity. Also, the electronegativity, polarization, first ionization potential, hydrogen bond potential, the molecular size, and shape of alkaloids are critical properties to determine alkaloids-SC6A binding constant as well as electronegativity, polarization, hydrophobicity, and the molecular size and shape of alkaloids play an important role for the alkaloids-SC8A binding constant.


Asunto(s)
Alcaloides , Medicina Tradicional China , Alcaloides/química
17.
Dalton Trans ; 53(6): 2687-2695, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38226466

RESUMEN

The supramolecular crystals, Mn(15-crown-5)(MnCl4)(DMF), (1; 15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane), were synthesized via a self-assembly strategy under ambient conditions. Comprehensive characterization of the crystals involved microanalysis for C, H, and N elements, thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and single-crystal X-ray diffraction techniques. The results reveal that 1 undergoes a two-step thermotropic and isostructural phase transition at around 217 K and 351 K upon heating. All three phases belong to the same space group (P212121) with analogous cell parameters. These two phase transitions primarily involve the thermally activated ring rotational dynamics of the 15-crown-5 molecule, with only the transition at ca. 351 K being associated with a dielectric anomaly. 1 exhibits intense luminescence with a peak at ∼600 nm and a high quantum yield of 68%. The mechanisms underlying this intense luminescence are likely linked to low-symmetry ligand fields. Additionally, 1 displays phase transition-induced luminescence enhancement behavior, and the possible mechanism is further discussed.

18.
Materials (Basel) ; 17(2)2024 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-38276446

RESUMEN

The corrosion of grounding grid materials in soil is a prominent factor in power and electrical equipment failure. This paper aims to delve into the corrosion characteristics of grounding grid materials and the corresponding methods of safeguarding against this phenomenon. Firstly, the influencing factors of the soil environment on the corrosion of the grounding grid are introduced, including soil physicochemical properties, microorganisms, and stray currents. Then, the corrosion behavior and durability of common grounding grid materials such as copper, carbon steel, and galvanized steel are discussed in detail and compared comprehensively. In addition, commonly used protective measures in China and outside China, including anti-corrosion coatings, electrochemical protection, and other technologies are introduced. Finally, it summarizes the current research progress and potential future directions of this field of study.

19.
Inorg Chem ; 63(5): 2640-2646, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38252082

RESUMEN

Organic-inorganic silver halide hybrids show abundant phase transitions and thermochromism. However, it is very rare that silver halides exhibit thermochromism related to thermotropic structure phase transition. Herein, a bromoargentate hybrid, [Pr-dabco]2Ag4Br6 (1) (Pr-dabco+ = 1-propyl-1,4-diazabicyclo-[2.2.2]octan-1-ium), with tetranuclear [Ag4Br6]2- clusters was prepared and characterized by microanalysis, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, and thermogravimetric (TG) and differential scanning calorimetry (DSC) techniques. Interestingly, 1 undergoes an irreversible structure phase transition at ∼436 K in the first heating process, which is accompanied by an abrupt color change from colorless to yellow; however, a reversible color change between pale yellow and yellow is observed in the next heating-cooling cycles. Notably, DSC measurement revealed that a reversible phase transition is associated with the change in color between pale yellow and yellow, while the powder X-ray diffraction (PXRD) patterns corresponding to pale yellow and yellow phases are quite similar to each other. These observations demonstrate that thermochromism in the next heating-cooling runs is associated with a reversible structure phase transition, which perhaps concerns the disorder-order transformation of alkyl chains in the cationic ligand [Pr-dabco]+, and relevant to the anharmonic fluctuations of the Ag-Br and Ag-N bonds, a strong electron-phonon coupling effect is seen within the bromoargentate cluster.

20.
Fitoterapia ; 172: 105716, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37926399

RESUMEN

Four previously undescribed angucyclinones umezawaones A-D (1-4) were isolated from the liquid cultures of Umezawaea beigongshangensis. Their structures were determined by spectroscopic analyses, single crystal X-ray diffraction, quantum chemical 13C NMR and electronic circular dichroism calculations. All compounds displayed strong inhibitory activities against indoleamine 2,3-dioxygenase and tryptophan-2,3-dioxygenase in enzymatic assay, especially compound 2.


Asunto(s)
Actinobacteria , Triptófano Oxigenasa , Triptófano Oxigenasa/química , Triptófano Oxigenasa/metabolismo , Actinomyces/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenasa , Estructura Molecular
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