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1.
Article in English | MEDLINE | ID: mdl-38578856

ABSTRACT

Accurate screening of cancer types is crucial for effective cancer detection and precise treatment selection. However, the association between gene expression profiles and tumors is often limited to a small number of biomarker genes. While computational methods using nature-inspired algorithms have shown promise in selecting predictive genes, existing techniques are limited by inefficient search and poor generalization across diverse datasets. This study presents a framework termed Evolutionary Optimized Diverse Ensemble Learning (EODE) to improve ensemble learning for cancer classification from gene expression data. The EODE methodology combines an intelligent grey wolf optimization algorithm for selective feature space reduction, guided random injection modeling for ensemble diversity enhancement, and subset model optimization for synergistic classifier combinations. Extensive experiments were conducted across 35 gene expression benchmark datasets encompassing varied cancer types. Results demonstrated that EODE obtained significantly improved screening accuracy over individual and conventionally aggregated models. The integrated optimization of advanced feature selection, directed specialized modeling, and cooperative classifier ensembles helps address key challenges in current nature-inspired approaches. This provides an effective framework for robust and generalized ensemble learning with gene expression biomarkers. Specifically, we have opened EODE source code on Github at https://github.com/wangxb96/EODE.

2.
J Chem Phys ; 160(15)2024 Apr 21.
Article in English | MEDLINE | ID: mdl-38624129

ABSTRACT

Packaging insulation materials with high thermal conductivity and excellent dielectric properties are favorable to meet the high demand and rapid development of third generation power semiconductors. In this study, we propose to improve the thermal conductivity of epoxy resin (EP) by incorporating a three-dimensional boron nitride thermally conductive network. Detailedly, polyurethane foam (PU) was used as a supporter, and boron nitride nanosheets (BNNSs) were loaded onto the PU supporter through chemical bonding (BNNS@PU). After immersing BNNS@PU into the EP resin, EP-based thermally conductive composites were prepared by vacuum-assisted impregnation. Fourier transform infrared spectrometer and scanning electron microscope were used to characterize the chemical bonding and morphological structure of BNNS@PU, respectively. The content of BNNS in BNNS@PU/EP composites was quantitatively analyzed by TGA. The results show that the thermal conductivity of the BNNS@PU/EP composites reaches 0.521 W/m K with an enhancement rate η of 30.89 at an ultra-low BNNS filler content (5.93 wt. %). Additionally, the BNNS@PU/EP composites have excellent dielectric properties with the frequency range from 101 to 106 Hz. This paper provides an interesting idea for developing high thermal conductivity insulating materials used for power semiconductor packaging.

3.
J Chem Phys ; 160(9)2024 Mar 07.
Article in English | MEDLINE | ID: mdl-38441265

ABSTRACT

In order to prepare highly heat-resistant packaging insulation materials, in this paper, bismaleimide/epoxy resin (BMI/EP55) composites with different contents of BMI were prepared by melt blending BMI into amino tetrafunctional and phenolic epoxy resin (at a ratio of 5:5). The microstructures and thermal and electrical properties of the composites were tested. The electrostatic potential distribution, energy level distribution, and molecular orbitals of BMI were calculated using Gaussian. The results showed that the carbonyl group in BMI is highly electronegative, implying that the carbonyl group has a strong electron trapping ability. The thermal decomposition temperature of the composites gradually increased with the increase of BMI content, and the 20% BMI/EP55 composites had the highest heat-resistance index, along with a glass transition temperature (Tg) of >250 °C. At different test temperatures, with increase in the BMI content, the conductivity of epoxy resin composites showed a tendency to first decrease and then increase, the breakdown field strength showed a tendency to first increase and then decrease, and the dielectric constant was gradually decreased. Two trap centers were present simultaneously in the composites, where the shallow trap energy level is the deepest in 20% BMI/EP composites and the deep trap energy level is the deepest in 10% BMI/EP55 composites. Correspondingly, the 10% BMI/EP55 composite had a slower charge decay rate, while the 20% BMI/EP55 had a faster charge decay rate. In summary, the BMI/EP55 composites with high heat resistance and insulating properties were prepared in this study, which provided ideas for preparing high-temperature packaging insulating materials.

4.
J Phys Chem A ; 127(28): 5930-5941, 2023 Jul 20.
Article in English | MEDLINE | ID: mdl-37418642

ABSTRACT

Genetic algorithm (GA) optimization coupled with the semiempirical intermediate neglect of differential overlap (INDO)/CIS method is presented to inversely design the red thermally activation delayed fluorescent (TADF) molecules. According to the predefined donor-acceptor (DA) library to build an ADn-type TADF candidate, we utilized the chemical notation language SMILES code to generate a TADF molecule and apply the RDKit program to produce the initial 3D molecular structure. A combined fitness function is proposed to evaluate the performance of the functional-lead TADF molecule. The fitness function includes three key parameters, i.e., the emission wavelength, the energy gap (ΔEST) between the lowest singlet (S1)- and triplet (T1)-excited states, and the oscillator strengths for electron transition from S0 and S1. A cheap QM method, i.e., INDO/CIS, on the basis of an xTB-optimized molecular geometry is applied to quickly calculate the fitness function. Finally, the GA approach is utilized to globally search for the wavelength-specific TADF molecules under our predefined DA library, and the optimum 630 nm red and 660 nm deep red TADF molecules are inversely designed according to the evolution of molecular fitness functions.

5.
Mater Horiz ; 10(5): 1769-1779, 2023 May 09.
Article in English | MEDLINE | ID: mdl-36825539

ABSTRACT

Metamaterials, from concept to application level, is currently a high-trending topic. Due to the strict requirements of the simultaneous reasonable structural design and stability of materials, the construction of a high-performance metamaterial for extreme environments is still difficult. Here, combining metamaterial design with materials optimization, we propose a completely different strategy and synthesize a type of monomeric ceramic meta-atom to construct metamaterials. Based on a geometric design with multiple degrees of freedom and dielectric properties, hybrid anapole modes with impedance matching can be produced, experimentally inducing nearly perfect absorption with high temperature stability (high tolerable temperature of approximately 1300 °C, with almost zero temperature drift) in microwave/millimeter-wave bands. We surpass the oxidation temperature limitation of 800 °C in conventional plasmonic absorbers, and provide an unprecedented direction for the further development of integrated high-performance metamaterial wireless sensors responding to extreme environmental scenarios, which will also lead to a new direction of specific ceramic research toward device physics.

6.
World J Gastroenterol ; 28(25): 2900-2909, 2022 Jul 07.
Article in English | MEDLINE | ID: mdl-35978878

ABSTRACT

Gastric cancer (GC) is the fourth leading cause of cancer-related death. The occurrence and development of GC is a complex process involving multiple biological mechanisms. Although traditional regulation modulates molecular functions related to the occurrence and development of GC, the comprehensive mechanisms remain unclear. Ultraconserved region (UCR) refers to a genome sequence that is completely conserved in the homologous regions of the human, rat and mouse genomes, with 100% identity, without any insertions or deletions, and often located in fragile sites and tumour-related genes. The transcribed UCR (T-UCR) is transcribed from the UCR and is a new type of long noncoding RNA. Recent studies have found that the expression level of T-UCRs changes during the occurrence and development of GC, revealing a new mechanism underlying GC. Therefore, this article aims to review the relevant research on T-UCRs in GC, as well as the function of T-UCRs and their regulatory role in the occurrence and development of GC, to provide new strategies for GC diagnosis and treatment.


Subject(s)
RNA, Long Noncoding , Stomach Neoplasms , Animals , Conserved Sequence/genetics , Gene Expression Regulation, Neoplastic , Humans , Mice , RNA, Long Noncoding/genetics , Rats , Stomach Neoplasms/genetics , Stomach Neoplasms/therapy
7.
Comput Struct Biotechnol J ; 20: 2181-2197, 2022.
Article in English | MEDLINE | ID: mdl-35615016

ABSTRACT

With the development of next-generation sequencing technologies, single-cell RNA sequencing (scRNA-seq) has become one indispensable tool to reveal the wide heterogeneity between cells. Clustering is a fundamental task in this analysis to disclose the transcriptomic profiles of single cells and is one of the key computational problems that has received widespread attention. Recently, many clustering algorithms have been developed for the scRNA-seq data. Nevertheless, the computational models often suffer from realistic restrictions such as numerical instability, high dimensionality and computational scalability. Moreover, the accumulating cell numbers and high dropout rates bring a huge computational challenge to the analysis. To address these limitations, we first provide a systematic and extensive performance evaluation of four feature selection methods and nine scRNA-seq clustering algorithms on fourteen real single-cell RNA-seq datasets. Based on this, we then propose an accurate single-cell data analysis via Ensemble Feature Selection based Clustering, called scEFSC. Indeed, the algorithm employs several unsupervised feature selections to remove genes that do not contribute significantly to the scRNA-seq data. After that, different single-cell RNA-seq clustering algorithms are proposed to cluster the data filtered by multiple unsupervised feature selections, and then the clustering results are combined using weighted-based meta-clustering. We applied scEFSC to the fourteen real single-cell RNA-seq datasets and the experimental results demonstrated that our proposed scEFSC outperformed the other scRNA-seq clustering algorithms with several evaluation metrics. In addition, we established the biological interpretability of scEFSC by carrying out differential gene expression analysis, gene ontology enrichment and KEGG analysis. scEFSC is available at https://github.com/Conan-Bian/scEFSC.

8.
Article in Chinese | MEDLINE | ID: mdl-35483682

ABSTRACT

Objective:To analyze the related factors of secondary erythrocytosis of obstructive sleep apnea(OSA) in Gansu province. Methods:Polysomnography recording and analysis from January 2013 to January 2021, A total of 448 OSA patients of long-resident Han nationality in Gansu province. Hemoglobin(Hb) values were divided into group A(Hb 120-160 g/L) 41 cases, B(Hb 161-179 g/L) 142 cases, C(Hb 180-199 g/L) 152 cases, D(Hb 200-219 g/L) 79 cases, and E(Hb ≥220 g/L) 30 cases. General clinical data, altitude of residence, disease course, apnea hypopnea index (AHI), and Lowest oxyhemoglobin(LSpO2) were compared among these groups. Multivariate regression and ROC curves were used to analyze the influencing factors of OSA secondary erythrocytosis. Results:There were no significant differences in age, sex, and course of disease among groups A, B, C, D, and E (P>0.05).The altitude of group E was higher than that of groups A, B, C, and D (P<0.05), but there was no significant difference between groups A, B, C and D (P>0.05).AHI was significantly different among groups A, B, C, D, and E (P<0.05), groups C, D, and E were significantly higher than A; group D was significantly higher than B, C.LSpO2 was significantly different among groups A, B, C, D, and E (P <0.05), groups B, C, D, and E was significantly lower than A; group D, E was significantly lower than B, C.MSpO2 was significantly different among groups A, B, C, D, and E (P<0.05), groups B, C, D, and E was significantly lower A; groups D, E was significantly lower than B , C.Multivariate regression showed that the higher the altitude, the lower the MSpO2, the more serious the secondary hyperhemoglobinemia.Age, course of the disease, AHI, and LSpO2 were not the influencing factors of OSA secondary hemoglobin increase.The areas under the ROC curve for MSpO2 and altitude to predict Hb≥180 g/L were 0.694(P<0.001) and 0.570(P=0.009), with statistically significant differences(Z=3.205, P=0.001). Conclusion:Altitude and MSpO2 were independent risk factors for OSA secondary erythrocytosis; MSpO2 predicted that Hb≥180 g/L in OSA patients was better than altitude.


Subject(s)
Polycythemia , Sleep Apnea, Obstructive , Humans , Polycythemia/complications , Polysomnography , ROC Curve , Sleep Apnea, Obstructive/complications , Syndrome
9.
J Transl Med ; 20(1): 115, 2022 03 07.
Article in English | MEDLINE | ID: mdl-35255935

ABSTRACT

BACKGROUND: Gastric cancer (GC) is one of the most common malignancies, and an increasing number of studies have shown that its pathogenesis is regulated by various miRNAs. In this study, we investigated the role of miR-875-5p in GC. METHODS: The expression of miR-875-5p was detected in human GC specimens and cell lines by miRNA qRT-PCR. The effect of miR-875-5p on GC proliferation was determined by Cell Counting Kit-8 (CCK-8) proliferation and 5-ethynyl-2'-deoxyuridine (EdU) assays. Migration and invasion were examined by transwell migration and invasion assays as well as wound healing assays. The interaction between miR-875-5p and its target gene upstream stimulatory factor 2(USF2) was verified by dual luciferase reporter assays. The effects of miR-875-5p in vivo were studied in xenograft nude mouse models. Related proteins were detected by western blot. RESULTS: The results showed that miR-875-5p inhibited the proliferation, migration and invasion of GC cells in vitro and inhibited tumorigenesis in vivo. USF2 was proved to be a direct target of miR-875-5p. Knockdown of USF2 partially counteracted the effects of miR-875-5p inhibitor. Overexpression of miR-875-5p could inhibit proliferation, migration and invasion and suppress the TGF-ß signalling pathway by downregulating USF2. CONCLUSIONS: MiR-875-5p can inhibit the progression of GC by directly targeting USF2. And in the future, miR-875-5p is expected to be a potential target for GC diagnosis and treatment.


Subject(s)
MicroRNAs , Stomach Neoplasms , Animals , Carcinogenesis/genetics , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic , Humans , Mice , MicroRNAs/genetics , MicroRNAs/metabolism , Stomach Neoplasms/pathology , Transforming Growth Factor beta/metabolism , Upstream Stimulatory Factors/genetics , Upstream Stimulatory Factors/metabolism
10.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-920498

ABSTRACT

@#[摘 要] 目的:探讨miR-875-5p对胃癌细胞增殖、迁移和侵袭的影响及其机制。方法:采用qPCR法检测胃癌细胞BGC-823、HGC-27、MGC-803、SGC-7901、AGS、MKN-45 和胃黏膜上皮细胞GES-1中miR-875-5p的表达水平。利用脂质体转染技术,分别将miR-875-5p模拟物/抑制剂(mimic/inhibitor)及其阴性对照质粒(miR-NC/Anti-miR-NC)转染至AGS细胞/MKN-45细胞,构建过表达/抑制miR-875-5p的细胞模型,空白对照组(Control组)不转染。通过CCK-8、克隆形成、Transwell等实验分别检测miR-875-5p表达变化对细胞增殖、克隆形成、迁移和侵袭的影响。采用双荧光素酶报告基因实验验证miR-875-5p与上游刺激因子2(USF2)的靶向关系,WB实验验证miR-875-5p对USF2的调控作用并检测USF2蛋白的表达。构建MKN-45细胞裸鼠移植瘤模型,验证miR-875-5p过表达对MKN-45细胞成瘤能力的影响。结果:miR-875-5p在6种胃癌细胞中表达水平显著低于胃黏膜上皮细胞GES-1(均P<0.01)。与Control组和miR-NC组相比,miR-875-5p mimic组AGS细胞的增殖、克隆形成率、迁移和侵袭细胞数,以及USF2蛋白的表达均显著降低(P<0.05或P<0.01);miR-875-5p inhibitor组MKN-45细胞的增殖、克隆形成率、迁移和侵袭细胞数,以及USF2蛋白的表达均显著提高(P<0.05或P<0.01)。双荧光素酶报告基因实验证明,miR-875-5p能够直接靶向USF2基因。体内成瘤实验结果表明,过表达miR-875-5p显著抑制MKN-45细胞移植瘤的生长(均P<0.01)。结论:miR-875-5p通过靶向USF2抑制胃癌细胞的增殖、迁移和侵袭。

11.
Intern Med J ; 51(5): 732-738, 2021 May.
Article in English | MEDLINE | ID: mdl-32149434

ABSTRACT

BACKGROUND: Primary insomnia is a worldwide problem and it has a considerable negative impact on one's physical and mental health. Studies have shown that non-synonymous Single-nucleotide polymorphisms in 5-hydroxytryptamine (serotonin or 5-HT) are related to primary insomnia. Previous studies have shown that 5-HT polymorphism (rs140700) is related to depression, and insomnia is often accompanied by depression and anxiety. The relationship between this site and primary insomnia is unknown. We speculated that this site may be related to primary insomnia, so we investigated the relationship between rs140700 and primary insomnia. AIMS: To explore the relationship between the 5-HT gene polymorphism rs140700 and primary insomnia. METHODS: In this study, we included 57 patients with primary insomnia and 54 age- and gender-matched normal controls. The subjects who belonged to the Chinese population were subjected to polysomnography for three consecutive nights. Their sleep quality was assessed, and the genotypes of the 5-hydroxytryptamine (5-HT) gene polymorphism rs140700 were determined by the flight mass spectrometry. RESULTS: The genotype distributions of the 5-HT gene polymorphism rs140700 were in Hardy-Weinberg equilibrium in both patients and controls (P > 0.05). The allele and genotype distributions of this variant were comparable between the patients and controls in all subjects and between genders (all P > 0.05). The influence of rs140700 on percentage of stage 1 (P = 0.015) change and arousal index (P = 0.028) of primary insomnia was statistically significant. The logistic multi-factor regression analysis results revealed that 5-HT gene polymorphism rs140700 was not a risk factor for primary insomnia in the Chinese population (P = 0.589). CONCLUSIONS: The 5-HT gene polymorphism rs140700 may not be a susceptibility locus for primary insomnia in the Chinese population.


Subject(s)
Serotonin Plasma Membrane Transport Proteins/genetics , Serotonin , Sleep Initiation and Maintenance Disorders , Alleles , Asian People/genetics , Case-Control Studies , China/epidemiology , Female , Gene Frequency , Genetic Predisposition to Disease , Genotype , Humans , Male , Polymorphism, Single Nucleotide , Sleep Initiation and Maintenance Disorders/epidemiology , Sleep Initiation and Maintenance Disorders/genetics
12.
Chemistry ; 26(68): 16036-16042, 2020 Dec 04.
Article in English | MEDLINE | ID: mdl-32648593

ABSTRACT

By applying a chirality-assisted synthesis (CAS) approach enantiopure diaminodibromotriptycenes were converted to rigid chiral helical diazadibenzoanthracenes, which show besides pronounced Cotton effects in circular dichroism spectra higher photoluminescence quantum yields as comparable carbacyclic analogues. For the enantiopure building blocks, a protocol was developed allowing the large scale synthesis without the necessity of separation via HPLC.

13.
Materials (Basel) ; 12(1)2019 Jan 07.
Article in English | MEDLINE | ID: mdl-30621056

ABSTRACT

Rigid biological systems are increasingly becoming a source of inspiration for the fabrication of the advanced functional materials due to their diverse hierarchical structures and remarkable engineering properties. As a bionic biomaterial with a clear layered structure, excellent mechanical properties, and interesting rainbow colors, nacre has become one of the most attractive models for novel artificial materials design. In this research paper, the tough and strong nacre-like bio-hybrid membranes with an interpenetrating petals structure were fabricated from chitosan (CS) and magadiite (MAG) clay nanosheets through the gel-casting self-assembling method. The analyses from X-ray diffraction (XRD), scanning electron microscope (SEM), and observations of water droplets on membranes indicated that the nacre-like hybrid membranes had a layered compact structure. Fourier transforms infrared spectroscopy (FTIR) analyses suggested that the CS molecular chains formed chemical bonds and hydrogen bonds with MAG layers. The inter-penetrating petal layered structure had a good effect on the mechanical properties of a nacre-like bio-hybrid membranes and the tensile strength of the hybrid membranes could reach at 78.6 MPa. However, the transmission analyses of the results showed that the hybrid membranes still had a certain visible light transmittance. Finally, the hybrid membranes possessed an intriguing efficient fire-shielding property during exposure to the flame of alcohol burner. Consequently, the great biocompatibility and excellent mechanical properties of the bio-hybrid membranes with the special interpenetrating petals structure provides a great opportunity for these composites to be widely applied in biomaterial research.

14.
Angew Chem Int Ed Engl ; 58(2): 482-487, 2019 Jan 08.
Article in English | MEDLINE | ID: mdl-30380163

ABSTRACT

A new three-component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2-pyridinyl (Py) directing group, is described. The N-Py-amide substrates are readily prepared from carboxylic acids and PyNH2 , and the resulting N-Py-1-arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN-Py group with HCl. The 1-aryl-1-chloroalkane products allow substitution and cross-coupling reactions. Therefore, a general protocol for the transformation of carboxylic acids into a variety of functionalities is obtained. The Py-NH2 by-product can be recycled.

15.
R Soc Open Sci ; 5(5): 172124, 2018 May.
Article in English | MEDLINE | ID: mdl-29892399

ABSTRACT

A heterogeneous catalyst (ZnO/SFCCR) composed of ZnO supported on spent fluid cracking catalyst by wet impregnation was synthesized and applied to the esterification of colophony acids with methanol under subcritical CO2 conditions. The catalyst was characterized by SEM-EDS, BET, ICP, FTIR, XRD and Py-IR. An experimental set-up involving a new injection technique was designed to promote the heterogeneous methyl esterification, and the subcritical CO2 played a role in auxiliary acid catalysis (a pH range of 3.54-3.91), increasing the lifespan of ZnO/SFCCR, reducing the viscosity of the system to promote gas-liquid mass transfer. A maximum conversion rate of 97.01% was obtained in a relatively short time of 5 h. Kinetic experiments were performed from 190 to 220°C using a special high-temperature sampling device and analysing aliquots with high-performance liquid chromatography. A new reaction pathway, involving methyl abietate, methyl dehydroabietate, methyl neoabietate and methyl palustrate along with other kinds of colophony acids, was developed. The kinetic parameters were obtained using the Levenberg-Marquardt nonlinear least-squares method, and the activation energies for the isomerizations of neoabietic and palustric acids and for the methyl esterification of neoabietic, abietic, palustric and dehydroabietic acids were found to be 107.09, 113.95, 68.99, 49.85, 75.43 and 59.20 kJ mol-1, respectively. The results from the kinetic model were in good agreement with experimental values.

16.
Materials (Basel) ; 12(1)2018 Dec 28.
Article in English | MEDLINE | ID: mdl-30597910

ABSTRACT

Organically-modified magadiite (MAG⁻CTAB⁻KH550) was synthesized via ion-exchange method and condensation reaction in the presence of pure magadiite (MAG), cetyltrimethylammonium bromide (CTAB) and γ-aminopropyltriethoxysilane (KH550) in aqueous solution in this research. This new adsorbent material was studied using scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and N2 adsorption/desorption isotherms process. It was found that the MAG⁻CTAB⁻KH550 has high Brunaur-Emmet-Teller (BET) specific surface area and mesoporous pore size distribution which enhanced its ability to remove phenol in aqueous solution; and, the value of pH has a relatively large impact on the adsorption behavior of the sorbent. Finally, the adsorptive behavior of the mesoporous material on phenol was followed pseudo-second-order kinetic adsorption model. In contrast, the adsorption equilibrium isotherm was better performed Langmuir isotherm model than the Freundlich isotherm model; in addition, the results also showed that the MAG⁻CTAB⁻KH550 had a better adsorption capacity and removal efficiency than MAG.

17.
Sci Rep ; 7(1): 2406, 2017 05 25.
Article in English | MEDLINE | ID: mdl-28546556

ABSTRACT

To improve the recovery of copper, the viscosity of copper molten slag is decreased by the reduction of magnetic iron, which, in turn, accelerates the settling and separation of copper droplets from the slag. A new technology is proposed in which waste cooking oil is used as a reductant to reduce magnetic iron in the copper smelting slag and consequently reduce carbon emissions in the copper smelting process. A kinetic model of the reduction of magnetic iron in copper slag by waste cooking oil was built using experimental data, and the accuracy of the model was verified. The results indicated that the magnetic iron content in the copper slag decreased with increasing reduction time and an increase in temperature more efficiently reduced magnetic iron in the copper slag. The magnetic iron in the copper slag gradually transformed to fayalite, and the viscosity of the copper molten slag decreased as the magnetic iron content decreased during the reduction process. The reduction of magnetic iron in the copper molten slag using waste cooking oil was a first-order reaction, and the rate-limiting step was the mass transfer of Fe3O4 through the liquid boundary layer.


Subject(s)
Copper , Dietary Fats, Unsaturated/analysis , Iron , Algorithms , Copper/chemistry , Iron/chemistry , Kinetics , Models, Theoretical , Temperature , Viscosity , X-Ray Diffraction
18.
Angew Chem Int Ed Engl ; 56(4): 1116-1119, 2017 01 19.
Article in English | MEDLINE | ID: mdl-27996169

ABSTRACT

A palladium-catalyzed asymmetric allyl-allyl cross-coupling of acetates of racemic Morita-Baylis-Hillman adducts and allylB(pin) has been developed using a spiroketal-based bis(phosphine) as the chiral ligand, thus affording a series of chiral 1,5-dienes bearing a vinylic ester functionality in good yields, high branched regioselectivities, and uniformly excellent enantioselectivities (95-99 % ee). Further synthetic manipulations of the allylation products provided novel ways for rapid access to a range of chiral polycyclic lactones and polycyclic lactams, as well as the antidepressant drug (-)-Paroxetine, in high optical purities.

19.
J Ethnopharmacol ; 193: 617-626, 2016 Dec 04.
Article in English | MEDLINE | ID: mdl-27746335

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Fuzi, the processed lateral root of Aconitum carmichaelii Debeaux, is a traditional Chinese medicine used for its analgesic, antipyretic, anti-rheumatoid arthritis and anti-inflammation effects; however, it is also well known for its toxicity. Gancao, the root of Glycyrrhiza uralensis Fisch., is often used concurrently with Fuzi to alleviate its toxicity. However, the mechanism of detoxication is still not well clear. AIM OF THE STUDY: In this study, the effect of Gancao on the metabolic changes induced by Fuzi was investigated by NMR-based metabonomic approaches. MATERIALS AND METHODS: Fifty male Wistar rats were randomly divided into five groups (group A: control, group B: Fuzi decoction alone, group C: Gancao decoction alone, group D: Fuzi decoction and Gancao decoction simultaneously, group E: Fuzi decoction 5h after Gancao decoction) and urine samples were collected for NMR-based metabolic profiling analysis. Statistical analyses such as unsupervised PCA, t-test, hierarchical cluster, and pathway analysis were used to detect the effects of Gancao on the metabolic changes induced by Fuzi. RESULTS: The behavioral and biochemical characteristics showed that Fuzi exhibited toxic effects on treated rats (group B) and statistical analyses showed that their metabolic profiles were in contrast to those in groups A and C. However, when Fuzi was administered with Gancao, the metabolic profiles became similar to controls, whereby Gancao reduced the levels of trimethylamine N-oxide, betaine, dimethylglycine, valine, acetoacetate, citrate, fumarate, 2-ketoglutarate and hippurate, and regulated the concentrations of taurine and 3-hydroxybutyrate, resulting in a decrease in toxicity. Furthermore, important pathways that are known to be involved in the effect of Gancao on Fuzi, including phenylalanine, tyrosine and tryptophan biosynthesis, the synthesis and degradation of ketone bodies, and the TCA cycle, were altered in co-treated rats. CONCLUSIONS: Gancao treatment mitigated the metabolic changes altered by Fuzi administration in rats, demonstrating that dosing with Gancao could reduce the toxicity of Fuzi at the metabolic level. Fuzi and Gancao administered simultaneously resulted in improved toxicity reduction than when Gancao was administrated 5h prior to Fuzi. In summary, co-administration of Gancao with Fuzi reduces toxicity at the metabolic level.


Subject(s)
Aconitum/chemistry , Drugs, Chinese Herbal/pharmacology , Glycyrrhiza uralensis/chemistry , Metabolome/drug effects , Metabolomics/methods , Plant Extracts/toxicity , Animals , Behavior, Animal/drug effects , Cluster Analysis , Diterpenes , Drugs, Chinese Herbal/isolation & purification , Male , Nuclear Magnetic Resonance, Biomolecular , Plant Extracts/isolation & purification , Plant Roots/chemistry , Rats, Wistar
20.
J Am Chem Soc ; 136(1): 405-11, 2014 Jan 08.
Article in English | MEDLINE | ID: mdl-24328176

ABSTRACT

Exceptionally high activity (with a TON up to 4750) of the palladium complexes of SKP ligand was discovered in the catalysis of asymmetric allylic amination of MBH adducts with aromatic amines. A comprehensive mechanistic study indicates that the unique structural features of the SKP ligand, with a long P···P distance in its solid-state structure, were favorable for allowing two P atoms to play a bifunctional role in the catalysis. Herein, one of the P atom forms a C-P σ-bond with the terminal carbon atom of allyl moiety as a Lewis base, and an alternative P atom coordinates to Pd atom. The cooperative action of organo- and organometallic catalysis discovered in the present catalytic system is most likely responsible for its high activity, as well as excellent regio- and enantioselectivities. The mechanism disclosed in the present catalytic system is distinct from most of the currently recognized mechanisms for Pd-catalyzed allylic substitutions.

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