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1.
Plant Cell Environ ; 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38828861

RESUMEN

Cadmium (Cd) is a toxic metal that poses serious threats to human health. Rice is a major source of dietary Cd but how rice plants transport Cd to the grain is not fully understood. Here, we characterize the function of the ZIP (ZRT, IRT-like protein) family protein, OsZIP2, in the root-to-shoot translocation of Cd and intervascular transfer of Cd in nodes. OsZIP2 is localized at the plasma membrane and exhibited Cd2+ transport activity when heterologously expressed in yeast. OsZIP2 is strongly expressed in xylem parenchyma cells in roots and in enlarged vascular bundles in nodes. Knockout of OsZIP2 significantly enhanced root-to-shoot translocation of Cd and alleviated the inhibition of root elongation by excess Cd stress; whereas overexpression of OsZIP2 decreased Cd translocation to shoots and resulted in Cd sensitivity. Knockout of OsZIP2 increased Cd allocation to the flag leaf but decreased Cd allocation to the panicle and grain. We further reveal that the variation of OsZIP2 expression level contributes to grain Cd concentration among rice germplasms. Our results demonstrate that OsZIP2 functions in root-to-shoot translocation of Cd in roots and intervascular transfer of Cd in nodes, which can be used for breeding low Cd rice varieties.

2.
J Org Chem ; 89(21): 15941-15952, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39446016

RESUMEN

We disclose herein an efficient and facile method for the synthesis of SF5-containing isoquinolinediones with an all-carbon quaternary stereocenter via intramolecular pentafluorosulfanylation of acrylamides using SF5Cl as a pentafluorosulfanylation reagent. The protocol proceeds under mild reaction conditions and enjoys a broad substrate scope, wide functional group compatibility, and high atom- and step-economy. A radical mechanism involving the SF5 radical cascade addition/cyclization of acrylamides is proposed.

3.
Neurochem Res ; 48(11): 3327-3348, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37505366

RESUMEN

Stroke is an acute cerebrovascular disease resulting from either obstruction or rupture of a blood vessel in the brain. Oxidative stress (OS), referred to a status where cellular oxidative capacities overwhelm antioxidative defenses, is involved in the pathophysiology of stroke. The bibliometric analysis and in-depth review aim to depict the research trend of OS in stroke. Relevant scientific publications were acquired from the Web of Science Core Collection database. Scientific landscape of OS in stroke was illustrated by general quantitative trend, impactful journals, and co-authorship of various academic units (i.e., countries/regions, organizations, and authors). Furthermore, theme analysis predicting the hot research issues and frontiers was performed. 15,826 documents regarding OS in stroke were obtained over a time span of more than 20 years from 1992 to 2021. The overall tendency of publication counts was continuously on the rise. Bibliometric analysis indicated China and the United States were predominant in this study field, as reflected by their high publication counts and intensive collaboration with other countries. Current key research areas of OS in stroke may lie in the investigation of neuroinflammation, and interaction among multiple cell death mechanisms including apoptosis, autophagy, and ferroptosis to search for effective treatments. Moreover, another hot topic could be the association between air pollution and stroke, and its underlying mechanisms. As the exploration of OS in stroke is speculated to be a continuous hot spot in the future, this article may be helpful for researchers to conduct future studies with the understanding of influential academic forces and research highlights.


Asunto(s)
Accidente Cerebrovascular , Humanos , Estrés Oxidativo , Encéfalo , Bibliometría , Antioxidantes
4.
Molecules ; 28(4)2023 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-36838882

RESUMEN

Antibacterial resistance has become one of the most serious problems threating global health. To overcome this urgent problem, many scientists have paid great attention to developing new antibacterial drugs from natural products. Hence, for exploring new antibacterial drugs from Chinese medicine, a series of experiments were carried out for verifying and elucidating the antibacterial activity and mechanisms of madecassic acid (MA), which is an active triterpenoid compound isolated from the traditional Chinese medicine, Centella asiatica. The antibacterial activity was investigated through measuring the diameter of the inhibition zone, the minimum inhibitory concentration (MIC), the growth curve, and the effect on the bacterial biofilm, respectively. Meanwhile, the antibacterial mechanism was also discussed from the aspects of cell wall integrity variation, cell membrane permeability, and the activities of related enzymes in the respiratory metabolic pathway before and after the intervention by MA. The results showed that MA had an inhibitory effect on eight kinds of pathogenic bacteria, and the MIC values for Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Bacillus megaterium were 31.25, 62.5, 250, 125, 62.5, and 62.5 µg/mL, respectively. For instance, 31.25 µg/mL MA could inhibit the growth of Staphylococcus aureus within 28 h. The antibacterial mechanism experiments confirmed that MA could destroy the integrity of the cell membrane and cell wall of Staphylococcus aureus, causing the leakage of macromolecular substances, inhibiting the synthesis of soluble proteins, reducing the activities of succinate dehydrogenase and malate dehydrogenase, and interacting with DNA, leading to the relaxation and ring opening of supercoiled DNA. Besides, the activities of DNA topoisomerase I and II were both inhibited by MA, which led to the cell growth of Staphylococcus aureus being repressed. This study provides a theoretical basis and reference for the application of MA in the control and inhibition of food-borne Staphylococcus aureus.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Triterpenos , Staphylococcus aureus , Antibacterianos/farmacología , Triterpenos/farmacología , Pruebas de Sensibilidad Microbiana , Escherichia coli , Bacterias
5.
Molecules ; 28(4)2023 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-36838564

RESUMEN

The traditional herb Eleutherococcus henryi Oliv. is commonly used to treat inflammatory conditions including rheumatism, arthritis, and hepatitis, as well as mental fatigue and amnesia, according to traditional Chinese medicine (TCM) theory. Savinin is a natural lignan obtained from the roots of E. henryi. The present study was undertaken to determine whether savinin can relieve LPS-induced neuroinflammation and if so, what the mechanism is. Groups of male C57BL/6 mice were administered savinin (5, 10, 20 mg/kg) and DEX (10 mg/kg) by gavage once daily for a continuous 7 days. On the 5th day of continuous pre-administration, LPS (2.5 mg/kg) was injected into the lateral ventricles of the mice for modeling 48 h. We found that treatment with savinin decreased the levels of neuroinflammatory cytokines and histopathological alterations dramatically. Consequently, it improved the LPS-induced neuroinflammatory response in mice. Furthermore, savinin inhibited the up-regulated expression of related proteins in the activated MAPK/NF-κB and NLRP3 inflammasome signaling pathways caused by LPS. Docking studies demonstrated the binding of savinin to three receptors (MAPK, NF-κB and NLRP3) using a well-fitting mode. These findings suggest that savinin may suppress neuroinflammation induced by LPS in vivo via modulating MAPK/NF-κB and NLRP3 signaling pathways.


Asunto(s)
Lignanos , Fármacos Neuroprotectores , Masculino , Ratones , Animales , FN-kappa B/metabolismo , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Lipopolisacáridos/farmacología , Enfermedades Neuroinflamatorias , Ratones Endogámicos C57BL , Inflamación
6.
Int J Mol Sci ; 23(8)2022 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-35457049

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) infection is challenging to eradicate because of antibiotic resistance and biofilm formation. Novel antimicrobial agents and alternative therapies are urgently needed. This study aimed to evaluate the synergy of sanguisorbigenin (SGB) isolated from Sanguisorba officinalis L. with six conventional antibiotics to achieve broad-spectrum antibacterial action and prevent the development of resistance. A checkerboard dilution test and time-to-kill curve assay were used to determine the synergistic effect of SGB combined with antibiotics against MRSA. SGB showed significant synergy with antibiotics and reduced the minimum inhibitory concentration of antibiotics by 2-16-fold. Biofilm inhibition assay, quantitative RT-PCR, crystal violet absorption, and transmission electron microscopy were performed to evaluate the synergy mechanism. The results indicated that SGB could inhibit biofilm formation and alter cell membrane permeability in MRSA. In addition, SGB was found to exhibit quite low cytotoxicity and hemolysis. The discovery of the superiority of SGB suggests that SGB may be an antibiotic adjuvant for use in combination therapy and as a plant-derived antibacterial agent targeting biofilms.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Antibacterianos/farmacología , Biopelículas , Permeabilidad de la Membrana Celular , Pruebas de Sensibilidad Microbiana
7.
Curr Microbiol ; 78(11): 3980-3988, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34557944

RESUMEN

Methicillin-resistant Staphylococcus (S.) aureus (MRSA) is a representative pathogen that produces numerous virulence factors involving manifold cytotoxins and exotoxins. The present study was designed to investigate the influence of Eleutheroside K (ETSK), a single compound isolated from the leaves of Acanthopanax (A.) henryi (Oliv.) Harms, on the exotoxins secreted by MRSA. The transcription and translation of the exotoxins (α-hemolysin and staphylococcal enterotoxins) related to virulence in S. aureus were determined via quantitative RT-PCR and western blot analysis. The effect of ETSK on the production of tumor necrosis factor (TNF)-α was evaluated using enzyme-linked immunosorbent assay. As a result, ETSK at sub-MIC concentrations could reduce the protein expression of α-hemolysin and enterotoxin, and the expression of genes that regulate virulence factors was also inhibited. In addition, the TNF-inducing activity of S. aureus was attenuated by ETSK in a dose-dependent manner. These results revealed that ETSK not only reduced the protein and gene expression levels of related exotoxins but also suppressed the ability of S. aureus to induce macrophages to release cytokines. This study indicated that the inhibition of MRSA infection by ETSK may be achieved by reducing the virulence of S. aureus and highlighted the potential of ETSK as an innovative strategy for the prevention and treatment of MRSA infections.


Asunto(s)
Eleutherococcus , Staphylococcus aureus Resistente a Meticilina , Staphylococcus aureus Resistente a Meticilina/genética , Extractos Vegetales , Staphylococcus aureus , Virulencia
8.
Molecules ; 26(8)2021 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-33921386

RESUMEN

Acanthopanax henryi (Oliv.) Harms (Araliaceae), also known as Eleutherococcus henryi and Caoyewujia (Hengliwujia) in Chinese, is a widely used traditional Chinese herb with the effects of expelling wind and removing dampness, relaxing the muscles and stimulating the blood circulation, and regulating the flow of qi to alleviate pain in the theory of Traditional Chinese Medicine. Acanthopanax henryi (AH, thereafter) possesses ginseng-like activities and is known as ginseng-like herb. In the past decade, a great number of phytochemical and pharmacological studies on AH have been carried out. Several kinds of chemical compositions have been reported, including terpenoids (monoterpenoids, diterpenoids, and triterpenoid saponins), phenylpropanoids, caffeoyl quinic acid derivatives, flavonoids, lignans, sterols, fatty acids, etc., among which, triterpenoid saponins were considered to be the most active components. Considerable pharmacological experiments in vitro have demonstrated that AH possessed anti-neuroinflammatory, anti-adipogenic, anti-inflammatory, antibacterial, anti-cancer, anti-oxidation, anti-AChE, anti-BuChE, and antihyaluronidase activities. The present review is an up-to-date and comprehensive analysis of the botany, phytochemistry, and pharmacology of AH.


Asunto(s)
Eleutherococcus/química , Etnofarmacología , Fitoquímicos/análisis , Fitoquímicos/química , Fitoquímicos/aislamiento & purificación , Investigación
9.
Molecules ; 23(4)2018 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-29671829

RESUMEN

Diabetes mellitus is a chronic degenerative disease that causes long-term complications and represents a serious public health problem. In this manuscript, acankoreagenin isolated from the leaves of Acanthopanax gracilistylus (LAG) is thought to possess excellent anti-diabetic properties. In vitro, anti-diabetic activities were assessed based on the inhibitory activities with α-glucosidase (IC50 13.01 µM), α-amylase (IC50 30.81 µM), and PTP1B (IC50 16.39 µM). Acankoreagenin showed better anti-diabetic effects. Then, an investigation was performed to analyze the insulin secretion effects of the insulin-secreting cell line in RIN-m5F cells. It was found that acankoreagenin could increase the insulin release in RIN-m5F cells. It was also found that acankoreagenin reduced NO production, activity of caspase-3, and the reactive oxygen species levels in the cells injured by processing of cytokines. In western blotting, inactivation of NF-κB signaling was confirmed. Acankoreagenin (20 µM) showed a higher I-κBα expression and lower NF-κB expression than the control group and showed a better expression than the positive control L-NAME (1 mM) (p < 0.05). This study demonstrates the anti-diabetic effects of acankoreagenin in vitro and suggests acankoreagenin might offer therapeutic potential for treating diabetes mellitus.


Asunto(s)
Eleutherococcus/química , FN-kappa B/metabolismo , Hojas de la Planta/química , Triterpenos/farmacología , Animales , Humanos , Hipoglucemiantes/farmacología , Proteína Tirosina Fosfatasa no Receptora Tipo 1/metabolismo , Transducción de Señal/efectos de los fármacos , alfa-Amilasas/metabolismo , alfa-Glucosidasas/metabolismo
10.
Molecules ; 23(1)2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29301264

RESUMEN

The phytochemical study on the leaves of Acanthopanax gracilistylus (Araliaceae) resulted in the discovery of a new lupane-triterpene compound, acangraciligenin S (1), and a new lupane-triterpene glycoside, acangraciliside S (2), as well as two known ones, 3α,11α-dihydroxy-lup-20(29)-en-23,28-dioic acid (3) and acankoreoside C (4). Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy. The chemical structures of the new compounds 1 and 2 were determined to be 1ß,3α-dihydroxy-lup-20(29)-en-23, 28-dioic acid and 1ß,3α-dihydroxy-lup-20(29)-en-23,28-dioic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-ß-d-glucopyranosyl-(1→6)-ß-d-glucopyranosyl] ester, respectively. The anti-neuroinflammatory activity of the selective compounds, 1 and 3, were evaluated with lipopolysaccharide (LPS)-induced BV2 microglia. The tested compounds showed moderate inhibitory effect of nitric oxide (NO) production.


Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Eleutherococcus/química , Triterpenos/química , Triterpenos/farmacología , Animales , Antiinflamatorios no Esteroideos/química , Evaluación Preclínica de Medicamentos/métodos , Lipopolisacáridos/farmacología , Espectroscopía de Resonancia Magnética , Ratones , Microglía/efectos de los fármacos , Microglía/metabolismo , Estructura Molecular , Óxido Nítrico/metabolismo , Hojas de la Planta/química
11.
Chemistry ; 23(49): 11771-11775, 2017 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-28695654

RESUMEN

A catalytic synthesis of amidines from amides has been established for the first time. The newly developed CO extrusion recombination process takes advantage of an inexpensive nickel(II) catalyst and provides the corresponding amidines with high efficiency. The intramolecular fragment coupling shows excellent chemoselectivity, starts from readily available amides, and provides a valuable alternative amidine synthesis protocol.

12.
Biosci Biotechnol Biochem ; 81(7): 1305-1313, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28345393

RESUMEN

We investigated the anti-inflammatory effects of 3α-hydroxy-lup-20(29)-en-23, 28-dioic acid (HLEDA)-a lupane-type triterpene isolated from leaves of Acanthopanax gracilistylus W. W.Smith (AGS), as well as the underlying molecular mechanisms in lipopolysaccharide (LPS)-induced RAW264.7 cells. Our results demonstrated that HLEDA concentration-dependently reduced the production of nitric oxide (NO), significantly suppressed LPS-induced expression of TNF-α and IL-1ß at the mRNA and protein levels in RAW264.7 cells. Further analysis revealed that HLEDA could reduce the secretion of High Mobility Group Box 1 (HMGB1). Additionally, the results showed that HLEDA efficiently decreased nuclear factor-kappaB (NF-κB) activation by inhibiting the degradation and phosphorylation of IκBα. These results suggest that HLEDA exerts anti-inflammatory properties in LPS-induced macrophages, possibly through inhibition of the NF-κB signaling pathway, which mediates the expression of pro-inflammatory cytokines. These results warrant further studies that would concern candidate therapy for diseases, such as fulminant hepatitis and rheumatology of triterpenoids in AGS.


Asunto(s)
Antiinflamatorios/farmacología , Medicamentos Herbarios Chinos/química , Proteína HMGB1/antagonistas & inhibidores , Interleucina-1beta/antagonistas & inhibidores , Macrófagos/efectos de los fármacos , Triterpenos/farmacología , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Animales , Antiinflamatorios/aislamiento & purificación , Línea Celular , Relación Dosis-Respuesta a Droga , Eleutherococcus , Expresión Génica , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Inflamación , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Lipopolisacáridos/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/metabolismo , Ratones , Inhibidor NF-kappaB alfa/antagonistas & inhibidores , Inhibidor NF-kappaB alfa/genética , Inhibidor NF-kappaB alfa/metabolismo , Óxido Nítrico/antagonistas & inhibidores , Óxido Nítrico/biosíntesis , Fosforilación/efectos de los fármacos , Triterpenos/aislamiento & purificación , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo
13.
Angew Chem Int Ed Engl ; 56(14): 3972-3976, 2017 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-28321978

RESUMEN

An inexpensive nickel(II) catalyst and a hydrosilane were used for the efficient reductive defunctionalization of aryl and heteroaryl esters through a decarbonylative pathway. This versatile method could be used for the removal of ester and amide functional groups from various organic molecules. Moreover, a scale-up experiment and a synthetic application based on the use of a removable carboxylic acid directing group highlight the usefulness of this reaction.

14.
Alcohol Clin Exp Res ; 40(7): 1489-500, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27265021

RESUMEN

BACKGROUND: Ethanol (EtOH) affects the immune system. Binge drinking of hard liquor initiates a stress response. This form of drinking is popular during adolescence, which involves maturation of the immune system. The spleen is a key immune organ, and spleen atrophy is associated with immunosuppression. While the hypothalamic-pituitary-adrenal (HPA) axis plays a key role in the initial stress response, the hippocampus may be involved in stress beyond the HPA axis. METHODS: Blood ethanol concentration (BEC), blood endotoxin levels, and plasma corticosterone levels were measured following binge EtOH treatment. Absolute and relative spleen sizes were analyzed, and stress-related gene expression was compared in the hypothalamus and hippocampus. Polymerase chain reaction array was performed to analyze the expression profile of EtOH metabolism and immune regulation-related genes in the spleen. Relationships among variables were analyzed using the Pearson correlation. RESULTS: At 24 hours following a 3-day EtOH treatment, no significant difference in BEC was detected between EtOH-treated and control rats. Average plasma endotoxin levels in EtOH-treated animals were significantly higher than in controls, and spleen size was significantly lower. Spleen size did not correlate with plasma endotoxin levels; however, it did significantly negatively correlate with plasma corticosterone levels. Spleen size significantly negatively correlated with hippocampal CRH expression and significantly positively correlated with hippocampal MR expression. No correlation was observed in the hypothalamus. Significantly higher hippocampal CRH and significantly lower MR expression was seen in low spleen/body weight (sp-wt) ratio rats. No gene was found to decrease expression ≥1.5-fold (p < 0.05) in the spleen of high sp-wt group, whereas expression of several genes, including Gabra1, Gabra5, Ifnb1, Irf9, Il12b, and Cx3cr1, decreased significantly in the low sp-wt group. CONCLUSIONS: Our findings suggest that binge EtOH exposure causes lower spleen size in adolescents and that the hippocampus and stress may be associated with alterations in spleen structure and gene expression.


Asunto(s)
Atrofia/patología , Consumo Excesivo de Bebidas Alcohólicas/patología , Etanol/efectos adversos , Hipocampo/metabolismo , Bazo/patología , Animales , Consumo Excesivo de Bebidas Alcohólicas/sangre , Corticosterona/sangre , Hormona Liberadora de Corticotropina/biosíntesis , Endotoxinas/sangre , Etanol/sangre , Expresión Génica/efectos de los fármacos , Hipotálamo/metabolismo , Masculino , Ratas , Receptores de Mineralocorticoides/biosíntesis
15.
J Sep Sci ; 39(12): 2252-62, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27121301

RESUMEN

Triterpenoid saponins are difficult to analyze using high-performance liquid chromatography coupled to UV/vis spectrophotometry due to their lack of chromophores. This study describes the first analytical method for the determination of 15 triterpenoid saponins from the leaves, stems, root bark, and fruits of Acanthopanax henryi, using a high-performance liquid chromatography with charged aerosol detection coupled with electrospray ionization mass spectrometry method. The separation was carried out on a Kinetex XB-C18 column with an acetonitrile/water gradient as the mobile phase, followed by charged aerosol detection. The operating conditions of charged aerosol detection were set at 24 kPa for nitrogen pressure and 100 pA for the detection range. Liquid chromatography with electrospray ionization mass spectrometry is described for the identification of compounds in plant samples. The electrospray ionization mass spectrometry method involved the use of the [M + Na](+) and [M + NH4 ](+) ions for compounds 1-15 in the positive ion mode with an extracted ion chromatogram. The developed method was fully validated in terms of linearity, sensitivity, precision, repeatability, and recovery, then subsequently applied to evaluate the quality of A. henryi.


Asunto(s)
Aerosoles/análisis , Eleutherococcus/química , Saponinas/análisis , Triterpenos/análisis , Cromatografía Liquida , Espectrometría de Masa por Ionización de Electrospray
16.
Angew Chem Int Ed Engl ; 55(49): 15415-15419, 2016 12 05.
Artículo en Inglés | MEDLINE | ID: mdl-27897421

RESUMEN

A nickel-catalyzed alkylation of polycyclic aromatic methyl ethers as well as methyl enol ethers with B-alkyl 9-BBN and trialkylborane reagents that involves the cleavage of stable C(sp2 )-OMe bonds is described. The transformation has a wide substrate scope and good chemoselectivity profile while proceeding under mild reaction conditions; it provides a versatile way to form C(sp2 )-C(sp3 ) bonds that does not suffer from ß-hydride elimination. Furthermore, a selective and sequential alkylation process by cleavage of inert C-O bonds is presented to demonstrate the advantage of this method.

17.
Angew Chem Int Ed Engl ; 55(20): 6093-8, 2016 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-27062726

RESUMEN

In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C-O bond-cleaving alkylation, for the first time without the limiting ß-hydride elimination. This new nickel-catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole derivatives. The directing and/or activating properties of aromatic methoxy groups are utilized first, before they are replaced by alkyl chains in a subsequent coupling process.

18.
J Am Chem Soc ; 137(21): 6746-9, 2015 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-25938599

RESUMEN

The rhodium-catalyzed asymmetric hydroboration of α-arylenamides with BI-DIME as the chiral ligand and (Bpin)2 as the reagent yields for the first time a series of α-amino tertiary boronic esters in good yields and excellent enantioselectivities (up to 99% ee).


Asunto(s)
Amidas/química , Ácidos Borónicos/síntesis química , Ésteres/síntesis química , Ácidos Borónicos/química , Ésteres/química , Estructura Molecular , Estereoisomerismo
19.
Polymers (Basel) ; 16(17)2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39274031

RESUMEN

In response to an investigation on the paths of changes in the crystallization and radial differences during the forming process of nascent fibers, in this study, we conducted numerical simulation and analyzed the changes in crystallization mechanical parameters and tensile properties through a fluid dynamics two-phase model. The model was based on the melt-spinning method focusing on melt spinning, the environment of POLYFLOW, and the method of joint simulation, coupled with Nakamura crystallization kinetics, including the development of process collaborative parameters, stretch-induced crystallization, viscoelasticity, filament cooling, gravity term, inertia, and air resistance. Finally, for nylon 6 BHS and CN9987 resin spinning, the model successfully predicted the distribution changes in temperature, velocity, strain rate tensor, birefringence, and stress tensor along the axial and radial fibers and obtained the variation pattern of fibers' crystallinity along the entire spinning process under different stretching rates. Furthermore, we also explored the effects of spinning conditions, including inlet flow rate, winding speeds, and the extrusion temperature, on the fibers' crystallization process and obtained the influence rules of different spinning conditions on fiber crystallization. Knowing the paths of changes in mechanical performance can provide important guidance and optimization strategies for the future industrial preparation of high-performance fibers.

20.
Alcohol Clin Exp Res (Hoboken) ; 48(1): 72-87, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38059389

RESUMEN

BACKGROUND: Organ weight change is widely accepted as a measure of toxicologic pathology. We and other groups have shown that excessive alcohol exposure leads to decreased spleen weight in rodents. This study explores the mechanisms underlying alcohol-induced splenic injury through a network meta-analysis. METHODS: QIAGEN Ingenuity Pathway Analysis (IPA) and Mammalian Phenotype (MP) Ontology were used to identify alcohol-related molecules associated with the small spleen phenotype. Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and IPA bioinformatics tools were then used to analyze the biologic processes and enriched signaling pathways engaging these molecules. In addition, the "downstream effects analysis" algorithm was used to quantify alcohol's effects. RESULTS: IPA identified 623 molecules affected by alcohol and a Venn diagram revealed that 26 of these molecules overlapped with those associated with the MP Ontology of small spleen. The 26 molecules are TGFB1, CASP8, MTOR, ESR1, CXCR4, CAMK4, NFKBIA, DRD2, BCL2, FAS, PEBP1, TRAF2, ATM, IGHM, EDNRB, MDM2, GLRA1, PRF1, TLR7, IFNG, ALOX5, FOXO1, IL15, APOE, IKBKG, and RORA. Some of the 26 molecules were also associated with the MP Ontology of abnormal white pulp and red pulp morphology of the spleen, abnormal splenic cell ratio, decreased splenocyte number, abnormal spleen physiology, increased splenocyte apoptosis, and reduced splenocyte proliferation. STRING and IPA "Core Analysis" showed that these molecules were mainly involved in pathways related to cell apoptosis, proliferation, migration, and immune responses. IPA's "Molecular Activity Predictor" tool showed that concurrent effects of activation and inhibition of these molecules led to decreased spleen size by modulating apoptosis, proliferation, and migration of splenocytes. CONCLUSIONS: Our network meta-analysis revealed that excessive alcohol exposure can damage the spleen through a variety of molecular mechanisms, thereby affecting immune function and human health. We found that alcohol-mediated splenic atrophy is largely mediated by increased apoptosis signaling, migration of cells, and inhibition of splenocyte proliferation.

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