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1.
Artículo en Inglés | MEDLINE | ID: mdl-39233456

RESUMEN

OBJECTIVE: We conducted a prospective randomized clinical trial to compare the efficacy of low- and high-dose radioiodine for remnant ablation in patients with low-risk differentiated thyroid cancer (DTC) in China. The first-stage results showed equivalence was observed between the two groups. Here, we report recurrence and survival at 3-5 and 6-10 years and biochemical parameters. DESIGN, PATIENTS AND METHODS: Between January 2013 and December 2014, adult patients with DTC were enroled. Patients had undergone total or near-total thyroidectomy, with or without cervical lymph node dissection, with tumour stages T1-T3 with or without lymph node metastasis, but without distant metastasis. Patients were randomly assigned to the low-dose (1850 MBq) or high-dose (3700 MBq) radioiodine group. They were then followed up for 3-5 and 6-10 years. Data on biochemical abnormalities, recurrence and survival were analysed using Kolmogorov-Smirnov and χ2 tests. RESULTS: The data of 228 patients (mean age = 42 years; 70.6% women) were analysed, with 117 patients in the low-dose group and 111 in the high-dose group. There were no significant differences in biochemical abnormalities, recurrence, or survival rates at the 6-10-year follow-up (all p > .05). Nine patients experienced recurrence in the low-dose group (8.7%), while eight patients experienced recurrence in the high-dose group (8.2%). The survival rates were 100% and 98.2% in the low- and high-dose groups, respectively. CONCLUSIONS: The long-term effectiveness and safety of low-dose (1850 MBq) radioiodine are the same as those of high-dose (3700 MBq) radioiodine for thyroid remnant ablation in Chinese patients with low-risk DTC.

2.
Adv Mater ; : e2410422, 2024 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-39300910

RESUMEN

The sluggish kinetics of hydrogen evolution reaction (HER) via water reduction limits the efficiency of alkaline water electrolysis. The HER kinetics is not only intimately related to the catalyst surface structure but also relevant to the cation identity of the electrolyte. The cation dependence also relies on the surface electronic structure and applied potential, but this interrelated effect and its underlying mechanism awaits elucidation. Herein, differently-charged molybdenum sulfide (MoSx) cluster supports ([Mo3S13]2- and [Mo3S7]4+) are utilized to hybridize with the identical metallic Ru centers. The specific electrostatic interaction between MoSx clusters and Ru precursors induces different Ru valences of the hybrids, with a higher valence state for Ru/Mo3S13 endowing a higher activity. The Ru/Mo3S13 and Ru/Mo3S7 exhibited drastically-different cation dependence, in which the charged support determines the local accumulation of cations and resulting water structures. The more negatively-charged Mo3S13 support induces the facile accumulation of cations, especially for less-hydrated K+ cations. The water activation capability by Ru valences and cation accumulation from the support effect in-together determine the cation-dependent alkaline HER activity. This work not only enriches the understanding about the cation-dependent HER mechanism but also shines a light on the rational optimization strategy of electrode/electrolyte interfaces.

3.
Int J Biol Macromol ; 279(Pt 1): 135172, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39208526

RESUMEN

Demethylation modification of lignin is an effective strategy to overcome the barrier to its high-value conversion. The purpose of this study focuses on the new proton-based ionic liquid (PIL) 1, 2-propanediamine/glycolic acid (PD/GA) as a catalyst and solvent to achieve the targeted oxidation of lignin. The PD/GA solvents have higher selectivity and efficiency. Optimal phenolic hydroxyl (PH)-increment was achieved, demonstrating enhanced demethylating effect on lignin by modulating the acid-base molar ratio, reaction temperature, and reaction time. Compared to ethanolamine/acetic acid (CE/AC) treatment, the PD/GA treatment at molar ratio 1.25, temperature 60 °C, and 3 h increased the PH-content from 37.74 to 59.91 %. Additionally, the lignin treated with PD/GA exhibited excellent recyclability, featuring a larger Brunauer-Emmett-Teller surface area (1.45 m2.g-1), total pore volume (9.51*10-3 cm3.g-1), and mesoporous size (26.15 nm). The treated lignin yielded maximum ultraviolet resistance and antioxidant activity. These results present new avenues for the development of green and efficient lignin demethylation methods.

4.
Eur Radiol ; 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38758254

RESUMEN

OBJECTIVES: To evaluate the association between metabolic response on 18F-FDG PET/CT and long-term survival in children with neuroblastoma (NB). METHODS: A total of 39 consecutive children with newly diagnosed stage 4 NB undergoing both 18F-FDG PET/CT imaging at baseline and after chemotherapy were retrospectively analyzed. The associations between metabolic parameters, including SUVmax of the lesion with the most intense 18F-FDG uptake at baseline (SUVb), after chemotherapy (SUVe), and the percentage change between SUVb and SUVe, and long-term survival were evaluated. RESULTS: With a median follow-up of 56 months, 22 patients who had achieved complete resolution on PET (no residual 18F-FDG uptake higher than the surrounding backgrounds) after chemotherapy had superior 5-year overall survival (OS) (73.6% vs. 39.0%, p = 0.044). SUVb > 6.9 indicated significantly poorer 5-year event-free survival (EFS) (12.5% vs. 59.3%, p = 0.005), as did SUVe > 1.2 (18.8% vs. 41.7%, p = 0.041). Children with SUVe > 1.2 had shorter 5-year OS (33.9% vs. 75.0%, p = 0.018). Multivariate analysis identified SUVe > 1.2 as an independent predictor for both EFS [hazard ratio (HR), 3.479, 95% CI, 1.381-8.761, p = 0.008] and OS (HR, 6.948, 95% CI, 1.663-29.025, p = 0.008), while SUVb > 6.9 was a predictor for EFS (HR, 2.889, 95% CI, 1.064-7.842, p = 0.037). Among 11 children with both SUVb > 6.9 and SUVe > 1.2, all experienced disease progression or relapse within 2 years since diagnosis. CONCLUSION: 18F-FDG PET/CT could be of useful to evaluate treatment response in children with stage 4 NB. CLINICAL RELEVANCE STATEMENT: 18F-FDG PET/CT after chemotherapy exhibits prognostic significance in neuroblastoma and holds potential as an alternative imaging modality for response evaluation, especially in cases with metaiodobenzylguanidine-nonavid or persistent avid disease. KEY POINTS: The prognostic value of chemotherapy response on 18F-FDG PET/CT in advanced neuroblastoma is unknown. Higher 18F-FDG uptake after chemotherapy was associated with worse long-term event-free survival and overall survival. 18F-FDG PET/CT after chemotherapy holds prognostic significance in children with stage 4 neuroblastoma.

5.
Angew Chem Int Ed Engl ; 63(21): e202319642, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38554014

RESUMEN

Maximizing the loadings of active centers without aggregation for a supported catalyst is a grand challenge but essential for achieving high gravimetric catalytic activity, especially toward multi-step reactions. The oxidation of 5-hydroxymethylfurfural (HMF), a key biomass-derived platform molecule, into 2,5-furandicarboxylic acid (FDCA), a promising alternative to polyester monomer, is such a multi-step reaction that involves 6 proton and electron transfers. This process often demands strong alkaline environment but also suffers from the alkali-driven polymerization side-reaction. Meanwhile, neutral media ameliorates the polymerization, but lacks efficient catalyst toward deep oxidation. Herein, we devised a strategy of creating ultra-dense supported Ru oxide clusters via directed ion exchange in a Co hydroxyanion (CoHA) support material. Pyrimidine ligands were first incorporated into the CoHA interlayers, and the subsequent evacuation of pyrimidines created porous channels for the directed ion exchange with the built-in anions in CoHA, which allowed the dense and mono-disperse functionalization of RuCl6 2- anions and their resulting Ru oxide clusters. These ultra-dense Ru oxide clusters not only enable high HMF electrooxidation currents under neutral conditions but also create microscopic channels in-between the clusters for the expedited re-adsorption and oxidation of intermediates toward highly oxidized product, such as 5-formyl-2-furoic acid (FFCA) and FDCA. A two-stage HMF oxidation process, consisting of ambient conversion of HMF into FFCA and FFCA oxidation into FDCA under 60 °C, was eventually developed to first achieve a high FDCA yield of 92.1 % under neutral media with significantly reduced polymerization.

6.
BMC Infect Dis ; 24(1): 314, 2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38486143

RESUMEN

BACKGROUND: Lassa fever is a hemorrhagic disease caused by Lassa virus (LASV), which has been classified by the World Health Organization as one of the top infectious diseases requiring prioritized research. Previous studies have provided insights into the classification and geographic characteristics of LASV lineages. However, the factor of the distribution and evolution characteristics and phylodynamics of the virus was still limited. METHODS: To enhance comprehensive understanding of LASV, we employed phylogenetic analysis, reassortment and recombination detection, and variation evaluation utilizing publicly available viral genome sequences. RESULTS: The results showed the estimated the root of time of the most recent common ancestor (TMRCA) for large (L) segment was approximately 634 (95% HPD: [385879]), whereas the TMRCA for small (S) segment was around 1224 (95% HPD: [10301401]). LASV primarily spread from east to west in West Africa through two routes, and in route 2, the virus independently spread to surrounding countries through Liberia, resulting in a wider spread of LASV. From 1969 to 2018, the effective population size experienced two significant increased, indicating the enhanced genetic diversity of LASV. We also found the evolution rate of L segment was faster than S segment, further results showed zinc-binding protein had the fastest evolution rate. Reassortment events were detected in multiple lineages including sub-lineage IIg, while recombination events were observed within lineage V. Significant amino acid changes in the glycoprotein precursor of LASV were identified, demonstrating sequence diversity among lineages in LASV. CONCLUSION: This study comprehensively elucidated the transmission and evolution of LASV in West Africa, providing detailed insights into reassortment events, recombination events, and amino acid variations.


Asunto(s)
Fiebre de Lassa , Virus Lassa , Humanos , Virus Lassa/genética , Filogenia , Fiebre de Lassa/epidemiología , Aminoácidos , Liberia
7.
Langmuir ; 40(4): 2191-2197, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38234120

RESUMEN

Centrifugation is one of the most commonly used methods for separation in biology and chemistry. However, effective fractionation is not always easy to obtain, as preparative centrifuge experiments are mostly conducted in an empirical way, even when it is guided by the quantitative results from analytical ultracentrifuge (AUC). Very few works have been performed to enhance the fractionation resolution of the differential centrifugation method in a swing-out rotor. This is primarily due to the absence of a characterization tool for sedimentation in the preparative centrifuge. In this study, we utilized image analysis to map the particle concentration distribution throughout the preparative centrifuge tube, revealing an unexpected and abnormal sedimentation process. By characterizing the sedimentation coefficient distributions of the fractionated product via AUC, we demonstrated that the overall sedimentation efficiency in a swing-out preparative centrifuge was significantly reduced. Furthermore, effective fractionation was confined to the intermediate phase of the entire sedimentation process. We propose that the mechanism here is a combination of the inverse Boycott effect and droplet sedimentation. The actual sedimentation process within a preparative centrifuge can be described by modifying the Lamm equation phenomenologically, which simply results in an effective sedimentation coefficient. Our work builds a foundation for determining the optimal preparative centrifugation conditions for various systems.

8.
Biochem Biophys Res Commun ; 680: 15-24, 2023 11 05.
Artículo en Inglés | MEDLINE | ID: mdl-37708598

RESUMEN

Hepatocellular carcinoma (HCC) is the world's third most fatal cancer. Because metabolic rewiring is a hallmark of HCC, studies into the causes of aberrant glycolysis could provide insight into novel HCC therapeutic strategies. Pyrroline-5-carboxylate reductase 2 (PYCR2), a key enzyme of proline synthesis, has previously been found to play vital roles in various malignancies regarding amino acid metabolism and oxidative stress response. Our study investigated the mechanistic function of PYCR2 in HCC. We used Gene Expression Profiling Interactive Analysis to perform bioinformatics analysis of PYCR2 expression and survival in human HCC patients based on the Cancer Genome Atlas database. The function of PYCR2 in cell viability and glycolysis was assessed using CCK-8 and ECAR assays. Transducing shRNA or overexpression vectors into the HCC cell line altered the expression status of PYCR2. PYCR2 expression was validated using quantitative real-time PCR and Western blot. In mouse xenograft models, the role of PYCR2 in HCC tumor formation was confirmed. PYCR2 was overexpressed in human HCC tumor tissue and was associated with a poor prognosis. The functional assay revealed that silencing PYCR2 inhibited cell viability, glycolysis, and AKT activation. Furthermore, the xenograft experiment demonstrated that silencing PYCR2 significantly inhibited tumor growth and Ki67 expression. On the other hand, PYCR2 overexpression significantly promoted cell viability and glycolysis, which could be inhibited by either a glycolysis inhibitor or an AKT inhibitor, indicating that PYCR2 may function via glycolysis and the AKT pathway. Moreover, despite the overexpression of PYCR2 in vivo, treatment with a glycolysis inhibitor may considerably suppress tumor growth. Our findings suggest that PYCR2 may play an oncogenic role in HCC growth by promoting glycolysis and activating AKT, emphasizing PYCR2's clinical relevance in HCC management as a novel potential therapeutic target.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animales , Ratones , Humanos , Neoplasias Hepáticas/patología , Carcinoma Hepatocelular/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Modelos Animales de Enfermedad , Proliferación Celular , Glucólisis , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Pirrolina Carboxilato Reductasas/genética , Pirrolina Carboxilato Reductasas/metabolismo
9.
Front Cell Infect Microbiol ; 13: 1180344, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37577376

RESUMEN

Nipah virus (NiV) and Hendra virus (HeV) are newly emerging dangerous zoonotic pathogens of the Henipavirus genus of the Paramyxoviridae family. NiV and HeV (HNVs) which are transmitted by bats cause acute respiratory disease and fatal encephalitis in humans. To date, as there is a lack of antiviral drugs or effective antiviral therapies, the development of vaccines against those two viruses is of primary importance, and the immunogen design is crucial to the success of vaccines. In this study, the full-length protein (G), the ectodomain (Ge) and the head domain (Gs) of NiV attachment glycoprotein were delivered by the replication-defective type 5 adenovirus vector (Ad5) respectively, and the recombinant Ad5-NiV vaccine candidates (Ad5-NiVG, Ad5-NiVGe and Ad5-NiVGs) were constructed and their immunogenicity were evaluated in mice. The results showed that all the vaccine candidates stimulated specific humoral and cellular immune responses efficiently and rapidly against both NiV and HeV, and the Ad5-NiVGe elicited the strongest immune responses after a single-dose immunization. Furthermore, the potent conserved T-cell epitope DTLYFPAVGFL shared by NiV and HeV was identified in the study, which may provide valid information on the mechanism of HNVs-specific cellular immunity. In summary, this study demonstrates that the Ad5-NiVGe could be a potent vaccine candidate against HNVs by inducing robust humoral and cellular immune responses.


Asunto(s)
Virus Hendra , Virus Nipah , Humanos , Animales , Ratones , Virus Hendra/fisiología , Virus Nipah/genética , Virus Nipah/metabolismo , Acoplamiento Viral , Glicoproteínas/genética , Glicoproteínas/metabolismo , Vacunas Sintéticas , Inmunidad Celular , Adenoviridae/genética
10.
Angew Chem Int Ed Engl ; 62(39): e202303200, 2023 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-37278979

RESUMEN

Neutral water oxidation is a crucial half-reaction for various electrochemical applications requiring pH-benign conditions. However, its sluggish kinetics with limited proton and electron transfer rates greatly impacts the overall energy efficiency. In this work, we created an electrode/electrolyte synergy strategy for simultaneously enhancing the proton and electron transfers at the interface toward highly efficient neutral water oxidation. The charge transfer was accelerated between the iridium oxide and in situ formed nickel oxyhydroxide on the electrode end. The proton transfer was expedited by the compact borate environment that originated from hierarchical fluoride/borate anions on the electrolyte end. These concerted promotions facilitated the proton-coupled electron transfer (PCET) events. Due to the electrode/electrolyte synergy, Ir-O and Ir-OO- intermediates could be directly detected by in situ Raman spectroscopy, and the rate-limiting step of Ir-O oxidation was determined. This synergy strategy can extend the scope of optimizing electrocatalytic activities toward more electrode/electrolyte combinations.

11.
Angew Chem Int Ed Engl ; 62(9): e202216083, 2023 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-36594790

RESUMEN

The electro-reforming of glycerol is an emerging technology of simultaneous hydrogen production and biomass valorization. However, its complex reaction network and limited catalyst tunability restrict the precise steering toward high selectivity. Herein, we incorporated the chelating phenanthrolines into the bulk nickel hydroxide and tuned the electronic properties by installing functional groups, yielding tunable selectivity toward formate (max 92.7 %) and oxalate (max 45.3 %) with almost linear correlation with the Hammett parameters. Further combinatory study of intermediate analysis and various spectroscopic techniques revealed the electronic effect of tailoring the valence band that balances between C-C cleavage and oxidation through the key glycolaldehyde intermediate. A two-electrode electro-reforming setup using the 5-nitro-1,10-phenanthroline-nickel hydroxide catalyst was further established to convert crude glycerol into pure H2 and isolable sodium oxalate with high efficiency.

12.
Front Oncol ; 12: 896593, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36353561

RESUMEN

Purpose: The substratification of high-risk neuroblastoma is challenging, and new predictive imaging biomarkers are warranted for better patient selection. The aim of the study was to evaluate the prognostic role of PET-based intratumor heterogeneity and its potential ability to improve risk stratification in neuroblastoma. Methods: Pretreatment 18F-FDG PET/CT scans from 112 consecutive children with newly diagnosed neuroblastoma were retrospectively analyzed. The primary tumor was segmented in the PET images. SUVs, volumetric parameters including metabolic tumor volume (MTV) and total lesion glycolysis (TLG), and texture features were extracted. After the exclusion of imaging features with poor and moderate reproducibility, the relationships between the imaging indices and clinicopathological factors, as well as event-free survival (EFS), were assessed. Results: The median follow-up duration was 33 months. Multivariate analysis showed that PET-based intratumor heterogeneity outperformed clinicopathological features, including age, stage, and MYCN, and remained the most robust independent predictor for EFS [training set, hazard ratio (HR): 6.4, 95% CI: 3.1-13.2, p < 0.001; test set, HR: 5.0, 95% CI: 1.8-13.6, p = 0.002]. Within the clinical high-risk group, patients with a high metabolic heterogeneity showed significantly poorer outcomes (HR: 3.3, 95% CI: 1.6-6.8, p = 0.002 in the training set; HR: 4.4, 95% CI: 1.5-12.9, p = 0.008 in the test set) compared to those with relatively homogeneous tumors. Furthermore, intratumor heterogeneity outran the volumetric indices (MTVs and TLGs) and yielded the best performance of distinguishing high-risk patients with different outcomes with a 3-year EFS of 6% vs. 47% (p = 0.001) in the training set and 9% vs. 51% (p = 0.004) in the test set. Conclusion: PET-based intratumor heterogeneity was a strong independent prognostic factor in neuroblastoma. In the clinical high-risk group, intratumor heterogeneity further stratified patients with distinct outcomes.

13.
Nanomaterials (Basel) ; 12(13)2022 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-35808046

RESUMEN

The synthesis of room temperature phosphorescent carbon dots (RTP-CDs) without any matrix is important in various applications. In particular, RTP-CDs with dual modes of excitation are more interesting. Here, we successfully synthesized matrix-free carbonized polymer dots (CPDs) that can generate green RTP under visible and ultraviolet light dual-mode excitation. Using acrylic acid (AA) and ammonium oxalate as precursors, a simple one-pot hydrothermal method was selected to prepare AA-CPDs. Here, acrylic acid is easy to polymerize under high temperature and high pressure, which makes AA-CPDs form a dense cross-linked internal structure. Ammonium oxalate as a nitrogen source can form amino groups during the reaction, which reacts with a large number of pendant carboxyl groups on the polymer chains to further form a cross-linked structure. The carboxyl and amino groups on the surface of AA-CPDs are connected by intermolecular hydrogen bonds. These hydrogen bonds can provide space protection (isolation of oxygen) around the AA-CPDs phosphor, which can stably excite the triplet state. This self-matrix structure effectively inhibits the non-radiative transition by blocking the intramolecular motion of CPDs. Under the excitation of WLED and 365 nm ultraviolet light, AA-CPDs exhibit the phosphorescence emission at 464 nm and 476 nm, respectively. The naked-eye observation exceeds 5 s and 10 s, respectively, and the average lifetime at 365 nm excitation wavelength is as long as 412.03 ms. In addition, it successfully proved the potential application of AA-CPDs in image anti-counterfeiting.

14.
J Chromatogr A ; 1673: 463091, 2022 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-35525192

RESUMEN

The separation of p-xylene (PX) and m-xylene (MX) isomers with near boiling points is a worldwide problem. The metal-organic framework material is an ideal stationary phase for chromatographic separation because of its high porosity, homogeneous pore diameter and good chemical stability. In this paper, a simulated moving bed (SMB) chromatography system with MIL-53(Fe) as the stationary phase and petroleum ether-dichloromethane as the mobile phase was designed to separate PX and MX at ambient temperature. Firstly, according to the elution curves of a single column, nonlinear competitive Langmuir adsorption isotherm equation was confirmed by equilibrium dispersive chromatography model. Then, the SMB separation zone was determined based on triangle theory, and the SMB operating conditions were optimized. Finally, the purity, recovery and productivity of PX reached 100.0%, 99.1% and 93.1 g/L/h, respectively; the purity, recovery and productivity of MX reached 96.4%, 100.0% and 23.5 g/L/h, respectively; the solvent consumption was 0.42 L/g.


Asunto(s)
Cromatografía , Xilenos , Adsorción , Cromatografía/métodos , Solventes/química
15.
Polymers (Basel) ; 13(17)2021 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-34502975

RESUMEN

A new type of economical covalent organic framework material(COF), namely resin based covalent organic framework material, was prepared by combining resin and covalent organic framework material by hydrothermal synthesis, which was based on the preparation of traditional COF material(TpBD COF). The properties of the material and covalent organic framework material were compared in the way of characterization, and the possible reaction mechanism was analyzed. The solid phase extraction separation (SPE) ability of this material for four kinds of phenolic endocrine disrupting compounds (bisphenol F, bisphenol A, octylphenol and nonylphenol) in beverage samples was investigated. The results showed that the prepared COF materials had abundant internal channels, ordered structure, large specific surface area (TpBD COF: 814.6 m2/g and resin based COF: 623.9 m2/g) and good thermal stability (pyrolysis temperature was 443 °C and 437 °C, respectively). Solid phase extraction experiments demonstrated that the two COF materials as adsorbent of solid phase extraction column had ideal adsorption separation effect and good anti-interference ability, and had strong anti-interference ability. The SPE effect was superior to the traditional solid phase extraction column. The precision RSD of this method was less than 3%. This SPE method had high recovery and could be reused (carbonated beverage: 98.18-102.18% and beverage: 98.52-101.79%), In addition, the recovery of the material did not change significantly in the 50 cycles of solid phase extraction, indicating that the material had good stability and could be reused, which could meet the requirements for the detection and analysis of trace pollutants in environmental samples. The resin based COF material prepared in this study could reduce the cost of monomer uses and provide a possibility for its industrial production. At the same time, as an efficient SPE adsorbent, it also provided a new research scheme for the enrichment of trace phenolic endocrine disruptors in beverage samples.

16.
J Chromatogr A ; 1653: 462388, 2021 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-34280789

RESUMEN

In this study, an enzyme immobilization method for the effective biotransformation of ginsenoside Rb1 to impart activity and stability was developed. Using a hydrolase enzyme model, ß-glucosidase from Aspergillus niger, immobilization within chemically affinity-linked amino-based silica provided an immobilization efficiency 5.86-fold higher than that of free enzyme. Compared with the free enzyme, the immobilized enzyme functioned optimally at a wider pH range and had higher thermostability. The optimum pH for the free and immobilized enzymes was 5.5. The optimal reaction temperature of the immobilized enzyme was 45 °C, which was 5 °C higher than that of the free enzyme. The Michaelis constant (Km) values before and after immobilization were 0.482 mmol•L-1 and 0.387 mmol•L-1, respectively. The catalytic rate (Kcat) for the immobilized and free enzymes was 22.269 mmol•L-1and 8.800 mmol•L-1, respectively, and the catalytic efficiency (Kcat/Km) activity of the immobilized enzyme was 3.30-fold higher than that of the free enzyme. The immobilized enzyme could preserve 97 % of the activity after 45 cycles of repeated use. The high catalytic activity and significant operational stability are beneficial for industrial applications.


Asunto(s)
Aspergillus niger , Ginsenósidos , Dióxido de Silicio , beta-Glucosidasa , Aspergillus niger/metabolismo , Biotransformación , Estabilidad de Enzimas , Enzimas Inmovilizadas/metabolismo , Ginsenósidos/química , Ginsenósidos/metabolismo , Concentración de Iones de Hidrógeno , Dióxido de Silicio/química , Temperatura , beta-Glucosidasa/metabolismo
17.
Molecules ; 26(10)2021 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-34067645

RESUMEN

A [3 + 2] 1,3-Dipolar cycloaddition of C,N-cyclic azomethine imines with allyl alkyl ketones has been achieved. The reaction proceeds under mild conditions and tolerates a wide range of functional groups. An array of tetrahydroisoquinoline derivatives is generally constructed with good diastereoselectivities and enantioselectivities (up to >25:1 dr, >95% ee). Moreover, the absolute configuration of the product was previously determined by using the quantum electronic circular dichroism calculation and ECD spectrum method.

18.
Infect Drug Resist ; 14: 2027-2038, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34103949

RESUMEN

PURPOSE: This study aimed to investigate the effects of aspirin (acetyl salicylic acid [ASA]) combined with fluconazole (FCA), itraconazole (ITR), or voriconazole (VRC) on Candida albicans under planktonic and biofilm conditions. METHODS: A total of 39 clinical C. albicans strains were used to perform the in vitro drug sensitivity assay under different conditions using the M27-A4 broth microdilution method. The minimal inhibitory concentrations (MICs) and fractional inhibitory concentration index (FICI) values were calculated. C. albicans ZY23 was chosen for the further analyses. RESULTS: Under planktonic conditions, the half maximal MIC (MIC50) values of FCA, ITR, and VRC were 64-0.5 µg/mL, 32-0.0625 µg/mL, and 16-0.125 µg/mL, respectively, when applied, whereas in combination with ASA, the values decreased to 32-0.25 µg/mL, 8-0.0313 µg/mL, and 8-0.0313 µg/mL, respectively. Under biofilm conditions, FCA, ITR, or VRC alone showed MIC50 values of 128-8 µg/mL, 32-4 µg/mL, and 32-0.5 µg/mL, whereas in combination with ASA the values were decreased to 32-0.5 µg/mL, 16-0.5 µg/mL, and 8-0.0625 µg/mL, respectively. Analysis of the FICI showed that the sensitization rate of ASA to FCA, ITR, and FCA under planktonic conditions was 43.59%, whereas the sensitization rates of ASP to FCA, ITR, and FCA under biofilm conditions were 46.15%, 46.15%, and 48.72%, respectively. Additionally, the time-growth and time-kill curves of C. albicans ZY23 further verified the synergistic effects of ASA on azole drugs. CONCLUSION: ASA may act as an enhancer of the inhibitory effects of azole drugs on the growth of clinical C. albicans under planktonic and biofilm conditions.

19.
Angew Chem Int Ed Engl ; 60(6): 3047-3054, 2021 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-33191586

RESUMEN

By manipulating the nucleation and growth of solid materials, the synthesis of various sophisticated nanostructures has been achieved. Similar methodology, if applied to liquids, could enable the mass-production and control of ultra-small droplets at the scale of nanoparticles (10-18  L or below). It would be highly desirable since droplets play a fundamental role in numerous applications. Here we present a general strategy to synthesize and manipulate nanoscale droplets, similar to what has been done to solid nanoparticles in classic solution-synthesis. It was achieved by a solute-induced phase separation which initiates the nucleation of droplets from a homogeneous solution. These liquid nanoparticles have great potentials to be manipulated like their solid counterparts, borrowing from the vast methodologies of nanoparticle synthesis, such as burst nucleation, seeded growth, and co-precipitation. Liquid nanoparticles also serve as a general synthetic platform, to fabricate nanoreactors, drug-loaded carriers, and other hollow nanostructures with a variety of shell materials.

20.
J Glob Antimicrob Resist ; 24: 32-39, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33242673

RESUMEN

OBJECTIVES: This study aimed to investigate the effects of caspofungin (CAS) combined with aspirin (ASP) or verapamil (VPL) on the sensitivity of Candida albicans under planktonic and biofilm conditions. METHODS: A total of 39 C. albicans clinical strains were used to construct biofilms. Sensitivity to ASP or VPL combined with CAS was analysed by broth microdilution. MIC50 values were obtained and the fractional inhibitory concentration index (FICI) was calculated. Subsequently, C. albicans ZY22 was selected for time-growth curve analysis and strains ZY15 and ZY22 were used for time-kill curve analysis. RESULTS: Under planktonic condition the MIC50 of CAS was 0.0313-8 µg/mL following treatment with CAS alone, whereas it decreased to 0.0313-4 µg/mL following CAS combined with ASP or VPL. Under biofilm condition the MIC50 of CAS was 0.125-16 µg/mL following treatment with CAS alone, whereas it decreased to 0.0625-16 µg/mL or 0.0625-8 µg/mL following CAS combined with ASP or VPL. FICI results showed synergistic interactions between CAS and ASP under planktonic and biofilm conditions in 17 and 16 strains, respectively. However, synergistic interactions between CAS and VPL under planktonic and biofilm conditions were observed in 19 and 23 strains, respectively. Additionally, 8000 µg/mL ASP or 8 µg/mL VPL combined with CAS had better inhibitory effects on C. albicans. CONCLUSION: ASP and VPL may be a sensitiser for CAS, and the antifungal effects of CAS may be sensitised by 8000 µg/mL ASP or 8 µg/mL VPL against C. albicans under planktonic and biofilm conditions.


Asunto(s)
Aspirina/farmacología , Candida albicans , Caspofungina/farmacología , Verapamilo/farmacología , Biopelículas , Candida albicans/efectos de los fármacos , Pruebas de Sensibilidad Microbiana
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