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1.
J Am Chem Soc ; 146(12): 8335-8342, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38487863

RESUMO

The inherent inertness and striking physicochemical similarities of krypton and xenon pose significant challenges to their separation. Reported herein is the efficient xenon capture and xenon/krypton adsorptive separation by transition metal-free zeolites under ambient conditions. The polarized environment of zeolite, denoted as local polarity, can be tuned by changing the topology, framework composition, and counter-cations, which in turn correlates with the guest-host interaction and separation performance. Chabazite zeolite with a framework Si/Al ratio of 2.5 and Ca2+ as the counter-cations, namely, Ca-CHA-2.5, is developed as a state-of-the-art zeolite adsorbent, showing remarkable performance, i.e., high dynamic xenon uptake, high xenon/krypton separation selectivity, and good recyclability, in the adsorptive separation of the xenon/krypton mixture. Grand Canonical Monte Carlo simulation reveals that extraframework Ca2+ cations act as the primary binding sites for xenon and can stabilize xenon molecules together with the chabazite framework, whereas krypton molecules are stabilized by weak guest-host interaction with the zeolite framework.

2.
J Am Chem Soc ; 144(9): 4260-4268, 2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35192361

RESUMO

Direct propylene epoxidation with molecular oxygen is a dream reaction with 100% atom economy, but aerobic epoxidation is challenging because of the undesired over-oxidation and isomerization of epoxide products. Herein, we report the construction of uniform cobalt ions confined in faujasite zeolite, namely, Co@Y, which exhibits unprecedented catalytic performance in the aerobic epoxidation of propylene. Propylene conversion of 24.6% is achieved at propylene oxide selectivity of 57% at 773 K, giving a state-of-the-art propylene oxide production rate of 4.7 mmol/gcat/h. The catalytic performance of Co@Y is very stable, and no activity loss can be observed for over 200 h. Spectroscopic analyses reveal the details of molecular oxygen activation on isolated cobalt ions, followed by interaction with propylene to produce epoxide, in which the Co2+-Coδ+-Co2+ (2 < δ < 3) redox cycle is involved. The reaction pathway of propylene oxide and byproduct acrolein formation from propylene epoxidation is investigated by density functional theory calculations, and the unique catalytic performance of Co@Y is interpreted. This work presents an explicit example of constructing specific transition-metal ions within the zeolite matrix toward selective catalytic oxidations.

3.
J Am Chem Soc ; 144(46): 21408-21416, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36303461

RESUMO

Olefin selectivity and catalyst lifetime are two key metrics for industrial methanol-to-olefin catalysts. Currently, it is very difficult to obtain high olefin selectivity and long catalyst lifetime at the same time. Herein, a feasible strategy combining precoking and steaming to directionally construct the active naphthalenic species within the crystal center of the SAPO-34 catalyst has been developed, which can not only promote the lower olefin selectivity to ∼89% (ethylene and propylene) but also prolong the catalyst lifetime by ∼3.7-fold in the methanol-to-olefin conversion. Structured illumination microscopy, in situ ultraviolet-visible spectroscopy, and online mass spectrometry elucidate the spatiotemporal distribution and evolution of the naphthalenic species during the precoking and steaming processes. This one-stone-two-birds strategy is applicable to a commercial SAPO-34 catalyst containing a binder, demonstrating its bright prospect in the methanol-to-olefin industry.

4.
Acc Chem Res ; 54(13): 2894-2904, 2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34165959

RESUMO

ConspectusZeolites, accompanied by their initial discovery as natural mines and the subsequent large-scale commercial production, have played indispensable roles in various fields such as petroleum refining and the chemical industry. Understanding the characteristics of zeolites, in contrast to their counterparts with similar chemical compositions and the origin thereof, is always a hot and challenging topic. Zeolites are known as intrinsic confined systems with ordered channels on the molecular scale, and structural confinement has been proposed to explain the unique chemical behaviors of zeolites. Generally, the channels of zeolites can regulate the diffusion of molecules, leading to a visible difference in molecular transportation and the ultimate shape-selective catalysis. On the other hand, the local electric field within the zeolite channels or cages can act on the guest molecules and change their energy levels. Confinement can be simply interpreted from both spatial and electronic issues; however, the nature of zeolite confinement is ambiguous and needs to be clarified.In this Account, we make a concise summary and analysis of the topics of confinement in a zeolite and zeolite catalysis from two specific views of spatial constraint and a local electric field to answer two basic questions of why zeolites and what else can we do with zeolites. First, it is shown how to construct functional sites including Brønsted acid sites, Lewis acid sites, extraframework cation sites, and entrapped metal or oxide aggregates in zeolites via confinement and how to understand the specific role of confinement in their reactivity. Second, the multiple impacts of confinement in zeolite-catalyzed reactions are discussed, which rationally lead to several unique processes, namely, Brønsted acid catalysis confined in zeolites, Lewis acid catalysis confined in zeolites, catalysis by zeolite-confined coordinatively unsaturated cation sites, and a cascade reaction within the confined space of zeolites. Overall, confinement effects do exist in zeolite systems and have already played extremely important roles in adsorption and catalysis. Although confinement might exist in many systems, the confinement by zeolites is more straightforward thanks to their well-ordered and rigid structure, deriving unique chemical behaviors within the confined space of zeolites. A zeolite is a fantastic scaffold for constructing isolated sites spatially and electrostatically confined in its matrix. Furthermore, zeolites containing well-defined transition-metal sites can be treated as inorganometallic complexes (i.e., a zeolite framework as the ligand of transition-metal ions) and can catalyze reactions resembling organometallic complexes or even metalloenzymes. The local electric field within the confined space of zeolites is strong enough to induce or assist the activation of small molecules, following the working fashion of frustrated Lewis pairs. The tactful utilization of structural confinement, both spatially and electronically, becomes the key to robust zeolites for adsorption and catalysis.

5.
Chemistry ; 28(50): e202201659, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-35726763

RESUMO

The development of cost-effective sorbents for direct capture of trace CO2 (<1 %) from the atmosphere is an important and challenging task. Natural or commercial zeolites are promising sorbents, but their performance in adsorption of trace CO2 has been poorly explored to date. A systematic study on capture of trace CO2 by commercial faujasite zeolites reveals that the extra-framework cations play a key role on their performance. Under dry conditions, Ba-X displays high dynamic uptake of 1.79 and 0.69 mmol g-1 at CO2 concentrations of 10000 and 1000 ppm, respectively, and shows excellent recyclability in the temperature-swing adsorption processes. K-X exhibits perfect moisture resistance, and >95 % dry CO2 uptake can be preserved under relative humidity of 74 %. In situ solid-state NMR spectroscopy, synchrotron X-ray diffraction and neutron diffraction reveal two binding sites for CO2 in these zeolites, namely the basic framework oxygen atoms and the divalent alkaline earth metal ions. This study unlocks the potential of low-cost natural zeolites for applications in direct air capture.

6.
BMC Public Health ; 22(1): 1752, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-36109743

RESUMO

BACKGROUND: To assess the interaction of sleep duration and depression on the risk of cardiovascular disease (CVD). METHODS: A total of 13,488 eligible participants were enrolled in this retrospective cohort study eventually. Baseline characteristics were extracted from the China Health and Retirement Longitudinal Study (CHARLS) database, including age, sex, diabetes, high-density lipoprotein (HDL), blood glucose (GLU), glycosylated hemoglobin (GHB) etc. Univariate and multivariate negative binomial regression models were carried out to assess the statistical correlation of sleep duration and depression on CVD separately. Additionally, multivariate negative binomial regression model was used to estimate the interaction of sleep duration and depression on CVD risk. RESULTS: After adjusting for age, sex, educational background, hypertension, diabetes, dyslipidemia, the use of hypnotics, disability, nap, drinking, deposit, sleep disturbance, HDL, triglyceride, total cholesterol, GLU and GHB, the risk of CVD in participants with the short sleep duration was increased in comparison with the normal sleep duration [relative risk (RR)=1.02, 95% confidence interval (CI):1.01-1.03]; compared to the participants with non-depression, participants suffered from depression had an increased risk of CVD (RR=1.05, 95%CI:1.04-1.06). Additionally, the result also suggested that the interaction between short sleep duration and depression on the risk of CVD was statistically significant in these patients with diabetes and was a multiplicative interaction. CONCLUSION: An interaction between short sleep duration and depression in relation to an increased risk of CVD among Chinese middle-aged and elderly individuals was noticed, which may provide a reference that people with diabetes should focus on their sleep duration and the occurrence of depression, and coexisting short sleep duration and depression may expose them to a higher risk of CVD.


Assuntos
Doenças Cardiovasculares , Depressão , Transtornos do Sono-Vigília , Idoso , Glicemia , Doenças Cardiovasculares/epidemiologia , Colesterol , Depressão/complicações , Hemoglobinas Glicadas , Humanos , Lipoproteínas HDL , Estudos Longitudinais , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Sono , Triglicerídeos
7.
J Am Chem Soc ; 143(4): 1993-2004, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33464884

RESUMO

Zeolite crystals offering a short diffusion pathway through the pore network are highly desired for a number of catalytic and molecule separation applications. Herein, we develop a simple synthetic strategy toward reducing the thickness along the b-axis of MFI-type crystals, thus providing a short diffusion path along the straight channel. Our approach combines preliminary aging and a fluoride-assisted low-temperature crystallization. The synthesized MFI crystals are in the micrometer-size range along the a- and c-axis, while the thickness along the b-axis is a few tens of nanometers. The synthesis parameters controlling the formation of platelike zeolite are studied, and the factors controlling the zeolite growth are identified. The synthesis strategy works equally well with all-silica MFI (silicalite-1) and its Al- and Ga-containing derivatives. The catalytic activity of platelike ZSM-5 in the methanol-to-hydrocarbons (MTH) reaction is compared with a commercial nanosized ZSM-5 sample, as the platelike ZSM-5 exhibits a substantially extended lifetime. The synthesis of platelike MFI crystals is successfully scaled up to a kilogram scale.

8.
J Am Chem Soc ; 143(49): 20898-20906, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34855383

RESUMO

Understanding the unique behaviors of atomically dispersed catalysts and the origin thereof is a challenging topic. Herein, we demonstrate a facile strategy to encapsulate Ptδ+ species within Y zeolite and reveal the nature of selective hydrogenation over a Pt@Y model catalyst. The unique configuration of Pt@Y, namely atomically dispersed Ptδ+ stabilized by the surrounding oxygen atoms of six-membered rings shared by sodalite cages and supercages, enables the exclusive heterolytic activation of dihydrogen over Ptδ+···O2- units, resembling the well-known classical Lewis pairs. The charged hydrogen species, i.e., H+ and Hδ-, are active reagents for selective hydrogenations, and therefore, the Pt@Y catalyst exhibits remarkable performance in the selective hydrogenation of α,ß-unsaturated aldehydes to unsaturated alcohols and of nitroarenes to arylamines.

9.
Angew Chem Int Ed Engl ; 60(12): 6526-6532, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33368904

RESUMO

The almost identical molecular sizes and volatilities of acetylene and carbon dioxide make their separation extremely challenging in industry. Reported here is the efficient separation of acetylene and carbon dioxide (v/v=2/1, which is relevant to that in the industrial cracking stream) in faujasite zeolites decorated with atomically-dispersed copper(II) sites under ambient conditions. In situ neutron powder diffraction and inelastic neutron scattering confirm that the confined copper(II) site displays chemoselective yet reversible binding to acetylene, whereas adsorbed carbon dioxide molecules are stabilized by weak host-guest supramolecular interactions with the framework oxygen centers, thus resulting in the efficient separation of these two gases under flow conditions. A designed adsorption-purging-desorption system based upon Cu@FAU is established for the recovery of high purity acetylene (98-99 %) from the mixture of acetylene and carbon dioxide, offering an unprecedented separation factor of 22.2 with an effective dynamic uptake of acetylene of 1.51 mmol g-1 at 298 K.

10.
J Am Chem Soc ; 141(25): 9920-9927, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31149823

RESUMO

The selective hydrogenation of alkynes to alkenes is an important type of organic transformation with large-scale industrial applications. This transformation requires efficient catalysts with precise selectivity control, and palladium-based metallic catalysts are currently employed. Here we show that four-coordinated cationic nickel(II) confined in zeolite can efficiently catalyze the selective hydrogenation of acetylene to ethylene, a key process for trace acetylene removal prior to the polymerization process. Under optimized conditions, 100% acetylene conversion and an ethylene selectivity up to 97% are simultaneously achieved. This catalyst system also exhibits good stability and recyclability for potential applications. Spectroscopy investigations and density functional theory calculations reveal the heterolytic dissociation of hydrogen molecules and the importance of hydride and protons in the selective hydrogenation of acetylene to ethylene. This work provides an efficient strategy toward active and selective zeolite catalysts by utilizing the local electrostatic field within the zeolite confined space for small-molecule activation and by linking heterogeneous and homogeneous catalysis.

11.
Mol Med ; 24(1): 62, 2018 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-30509178

RESUMO

BACKGROUND: Gold nanoparticles (AuNPs) have been widely studied for biomedical applications, although their safety and potential toxicity in pregnancy remains unknown. The aim of this study is to explore the effect of AuNPs maternal exposure at different gestational ages on fetal survival and development, as well as the potential mechanism of AuNPs affecting embryos and fetuses. METHODS: Thirty nm polyethylene glycol (PEG)-coated AuNPs (A30) were administered to pregnant mice via intravenous injection (5 µg Au/g body weight) over three days at either early or late pregnancy. Fetal abortion rate and morphological development in E16.5 were then detected in detail. The pregnant mice physiological states with A30 exposure were examined by biochemical, histological or imaging methods; and materno-fetal distribution of gold elements was assayed by electron microscopy and mass spectrometry. Murine embryonic stem cells derived embryoid-bodies or neuroectodermal cells were treated with A30 (0.0025 to 0.25 µg Au/mL) to examine A30 effects on expression levels of the germ differentiation marker genes. Tukey's method was used for statistical analysis. RESULTS: Exposure to A30 during early (A30E) but not late (A30L) pregnancy caused a high abortion rate (53.5%), lower fetal survival rate and abnormal decidualization compared with non-exposed counterparts. The developmental damage caused by A30 followed an "all-or-nothing" pattern, as the non-aborted fetuses developed normally and pregnancies maintained normal endocrine values. A30 caused minor impairment of liver and kidney function of A30E but not A30L mice. TEM imaging of fetal tissue sections confirmed the transfer of A30 into fetal brain and live as aggregates. qPCR assays showed A30 suppressed the expression of ectodermal, but not mesodermal and endodermal differentiation markers. CONCLUSIONS: These results illustrate that maternal A30 exposure in early pregnant results in A30 transfer into embryonic tissues, inhibiting ectodermal differentiation of embryonic stem cells, leading to abnormal embryonic development and abortion. While exposure to A30 during late pregnancy had little or no impact on dams and fetuses. These findings suggest the safety of biomedical applications employing AuNPs during pregnancy is strongly influenced by fetal maturity and gestational age at exposure and provide the clues for AuNPs safe application period in pregnancy.


Assuntos
Aborto Espontâneo/induzido quimicamente , Ectoderma/efeitos dos fármacos , Ouro/toxicidade , Troca Materno-Fetal , Nanopartículas Metálicas/toxicidade , Animais , Diferenciação Celular , Ectoderma/crescimento & desenvolvimento , Células-Tronco Embrionárias , Feminino , Desenvolvimento Fetal , Idade Gestacional , Camundongos Endogâmicos ICR , Gravidez
12.
Inorg Chem ; 57(9): 5030-5037, 2018 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-29667839

RESUMO

Two stable 3D polyoxometalate-based metal-organic frameworks (PMOFs), [CuI12(trz)8(H2O)2][α-SiW12O40]·2H2O (1) and [CuI12(trz)8Cl][α-PW12O40] (2) (Htrz = 1- H-1,2,4-triazole) based on Keggin-type POMs were successfully obtained and fully characterized. The basic building units of the two PMOFs are [CuI12(trz)8], but polyoxoanion (POA) template effect leads to different structures and properties: 1 represents an interesting example that [α-SiW12O40]4- locate in the nine-membered Cu-trz rings through Cu···O weak interactions to form a 3D framework, whereas 2 shows a 3D structure constructed from 2D bilayer cationic network [CuI12(trz)8Cl]3+ and [α-PW12O40]3- lying in the adjacent layers via Cu···O weak interactions. PMOF 1 as unusual visible-light photocatalyst exhibit significantly enhanced photocatalytic activity under visible-light and excellent stability during the photocatalysis process for recovering and recycling, as well as photocatalytic hydrogen evolution activity.

13.
Angew Chem Int Ed Engl ; 55(16): 4938-42, 2016 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-27079818

RESUMO

Based on the newly designed ligand 4'-(3,5-dicarboxyphenyl)-4,2':6',4''-terpyridine (DCTP), a unique semi-conductive 3D framework {[Cu(Ι)Cu(ΙΙ)2(DCTP)2]NO3⋅1.5 DMF}n (1) with a narrow band gap of 2.1 eV, was obtained and structurally characterized. DFT calculations with van de Waals correction employed to explore the electronic structure of 1, clearly revealed its semi-conductive behavior. Furthermore, we found that 1 exhibits a superior band alignment with water to produce hydrogen and degrade organic pollutants. Without adding any photosensitizers, 1 displays an efficiently photocatalytic hydrogen production in water based on the photo-generated electrons under UV/Vis light. 1 also exhibits excellent photo-degradation of methyl blue under visible-light owing to the strong oxidization of excited holes. It is the first example of MOFs with doubly photocatalytic activities related to photo-generated electrons and holes, respectively.

14.
Angew Chem Int Ed Engl ; 54(30): 8783-6, 2015 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-26096840

RESUMO

Experimental evidence for the presence of tert-butyl cations, which are important intermediates in acid-catalyzed heterogeneous reactions, on solid acids has still not been provided to date. By combining density functional theory (DFT) calculations with (1)H/(13)C magic-angle-spinning NMR spectroscopy, the tert-butyl cation was successfully identified on zeolite H-ZSM-5 upon conversion of isobutene by capturing this intermediate with ammonia.

15.
Phys Chem Chem Phys ; 15(26): 10978-88, 2013 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-23708180

RESUMO

The sole effect of surface/bulk defects of TiO2 samples on their photocatalytic activity was investigated. Nano-sized anatase and rutile TiO2 were prepared by hydrothermal method and their surface/bulk defects were adjusted simply by calcination at different temperatures, i.e. 400-700 °C. High temperature calcinations induced the growth of crystalline sizes and a decrease in the surface areas, while the crystalline phase and the exposed facets were kept unchanged during calcination, as indicated by the characterization results from XRD, Raman, nitrogen adsorption-desorption, TEM and UV-Vis spectra. The existence of surface/bulk defects in calcined TiO2 samples was confirmed by photoluminescence and XPS spectra, and the surface/bulk defect ratio was quantitatively analyzed according to positron annihilation results. The photocatalytic activity of calcined TiO2 samples was evaluated in the photocatalytic reforming of methanol and the photocatalytic oxidation of α-phenethyl alcohol. Based on the characterization and catalytic results, a direct correlation between the surface specific photocatalytic activity and the surface/bulk defect density ratio could be drawn for both anatase TiO2 and rutile TiO2. The surface defects of TiO2, i.e. oxygen vacancy clusters, could promote the separation of electron-hole pairs under irradiation, and therefore, enhance the activity during photocatalytic reaction.

16.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 33(10): 1356-60, 2013 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-24432679

RESUMO

OBJECTIVE: To study the protective mechanism of Huoxue Anxin Recipe (HAR) on peroxidation damage of acute myocardial infarction (AMI) rats. METHODS: The AMI rat model was established by occluding the left anterior descending coronary artery. Compound Danshen Dripping Pill (CDDP) was used as the positive control. CDDP and HAR were administered to rats for 7 successive days since modeling. The heart function was detected using color Doppler echocardiography. Activities of induced nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), total superoxide dismutase (tSOD) activity, and contents of malondialdehyde (MDA) were detected by ultraviolet spectrophotometer method. RESULTS: Compared with the sham-operation group, ejection fraction (EF) and fraction shortening (FS) rate significantly decreased in the model group (P < 0.01). Compared with the model group, EF and FS rate significantly increased in the HAR group, showing statistical difference (P < 0.05). There was no statistical difference in activities of serum iNOS, eNOS, or tSOD among all groups (P > 0.05). Compared with the sham-operation group, iNOS activities and MDA contents significantly increased in the myocardial tissue of the model group (P < 0.01), activities of eNOS and tSOD significant decreased (P < 0.01). Compared with the model group, iNOS activities in the myocardial tissue, MDA contents both in serum and the myocardial tissue significantly decreased (P < 0.05), activities of eNOS and tSOD significantly increased in the HAR group (P < 0.05). There was no statistical difference in each index between the CDDP group and the HAR group (P > 0.05). CONCLUSIONS: HAR could significantly improve cardiac functions of AMI rats. Its roles might be associated with regulating imbalanced iNOS/eNOS expressions and alleviating peroxidation damage of the myocardial tissue.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Estresse Oxidativo , Animais , Medicamentos de Ervas Chinesas/uso terapêutico , Masculino , Malondialdeído/metabolismo , Infarto do Miocárdio/tratamento farmacológico , Óxido Nítrico/metabolismo , Fitoterapia , Ratos , Ratos Wistar , Salvia miltiorrhiza , Superóxido Dismutase/metabolismo
17.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 33(12): 1648-52, 2013 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-24517063

RESUMO

OBJECTIVE: To explore the protective mechanism of Fengshiqing Recipe (FR) against bone destruction in collagen-induced arthritis (CIA) rats. METHODS: Rats were divided into four groups in the experiment,i.e., the blank control group, the model group, the MTX group (MTX, 1 mg/1 000 g), and the FR group (24 g crude FR/kg). The CIA model was prepared except the blank control group. Medication was started in the MTX group and the FR group from the 14th day after modeling to the 56th day. The toe volume was measured on every Tuesday and Friday. Expression levels of serum IL-17, RANKL, MIP-1alpha were detected after 3-and 6-week intervention. The bone scintigraphy with nuclide (SPECT), bone mineral density (BMD), and the pathological section were observed to assess the intervention of drugs of heat clearing blood activating actions in the bone destruction of CIA rats. RESULTS: From the 10th day of modeling, the volume of both toes started to swell and reached the peak at about 21 days. It was obviously shrunk at about 30 days. Of them, the swelling degree was milder in the MTX group and the FR group than in the model group. Compared with the model group at the same phase, the levels of IL-17 and RANKL decreased in the MTX group after 3 weeks of intervention (P < 0.01, P < 0.05). The IL-17 level decreased in the FR group after three weeks of intervention (P < 0.05). The RANKL level decreased in the MTX group and the FR group after 6 weeks of intervention (P < 0.01, P < 0.05). Compared with the model group and the MTX group, the overall BMD and ankle BMD increased in the FR group after 6 weeks of intervention (P < 0.01, P < 0.05). The ankle ROI/mandible and the toe ROI/mandible were elevated in the FR group after 3 weeks of intervention (P < 0.05). Pathological results suggested that the joint lacunae was significantly widened, the hyperplasia of the synovial tissue was so severe, and the bone tissue was destroyed in the model group. Compared with the model group, the aforesaid conditions were significantly improved in the MTX group and the FR group. The cartilage structure was complete. CONCLUSION: QR could inhibit decreased BMD, prevent bone destruction, which might be achieved by down-regulating expression levels of IL-17, RANKL, and MIP-1alpha through the osteo immunological Th/RANKL system,inhibiting maturation and differentiation of osteoclasts, thereby, inhibiting bone destruction.


Assuntos
Artrite Experimental/tratamento farmacológico , Artrite Experimental/metabolismo , Osso e Ossos/patologia , Medicamentos de Ervas Chinesas/farmacologia , Animais , Densidade Óssea , Osso e Ossos/efeitos dos fármacos , Quimiocina CCL3/metabolismo , Medicamentos de Ervas Chinesas/uso terapêutico , Feminino , Interleucina-17/metabolismo , Ligante RANK/metabolismo , Ratos , Ratos Sprague-Dawley
18.
Dalton Trans ; 52(27): 9398-9405, 2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37357995

RESUMO

Efficient synthesis of zeolites with different topologies is of great significance for both fundamental research and industrial application. Herein, the SSZ-23 zeolite, an odd zeolite containing 7-membered ring (7-MR) and 9-MR channels, has been synthesized under fluorine-free conditions via the route of pre-aging and pH regulation. By this novel synthesis route, the crystallization time can be significantly shortened to 3 days, nearly half as that by the conventional route in fluoride media. The pH value of the aging gel, i.e., the basicity, is found to play a key role in the synthesis, as SSZ-13 and SSZ-25 zeolites can be synthesized simply by changing the basicity of the same aging gel. Characterization results indicate that decreasing the basicity can promote the condensation between Si and Si/Al species and thus increase the framework density of the resulting zeolites. Finally, the dimethyl ether (DME) carbonylation reaction is employed to evaluate the catalytic properties of the above three zeolites with an identical chemical composition, and to reveal the unique confinement effect in various zeolite topologies.

19.
Natl Sci Rev ; 10(7): nwad043, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37547060

RESUMO

The selective hydrogenation of CO2 to methanol by renewable hydrogen source represents an attractive route for CO2 recycling and is carbon neutral. Stable catalysts with high activity and methanol selectivity are being vigorously pursued, and current debates on the active site and reaction pathway need to be clarified. Here, we report a design of faujasite-encaged mononuclear Cu centers, namely Cu@FAU, for this challenging reaction. Stable methanol space-time-yield (STY) of 12.8 mmol gcat-1 h-1 and methanol selectivity of 89.5% are simultaneously achieved at a relatively low reaction temperature of 513 K, making Cu@FAU a potential methanol synthesis catalyst from CO2 hydrogenation. With zeolite-encaged mononuclear Cu centers as the destined active sites, the unique reaction pathway of stepwise CO2 hydrogenation over Cu@FAU is illustrated. This work provides a clear example of catalytic reaction with explicit structure-activity relationship and highlights the power of zeolite catalysis in complex chemical transformations.

20.
Zhongguo Zhong Yao Za Zhi ; 37(7): 1012-6, 2012 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-22792808

RESUMO

OBJECTIVE: To observe the protective effect of combined administration of blood-activating drug and sedative drug on myocardial injury of acute myocardial infarction (AMI) rats. METHOD: The acute myocardial infarction (AMI) model was established by occluding the left descending coronary artery of Wistar rats. These rats were further divided into four groups (n = 15 per group): the sham-operated group, the AMI model group, the blood-activating drug group and the combined administration group. RESULT: Compared with the sham-operated group, the AMI model group showed significant decrease in ejection fraction (EF) and fractional shortening (FS) (P < 0.001) and notable increase in the left ventricular end-diastolic internal diameter (LVIDd) and left ventricular end-systolic internal diameter (LVIDs) (P < 0.01), with the infarct area of left ventricular front wall up to about 70%-90%. Besides, tissue was severely replaced by collagen deposition and fibrosis, the sarcomeres disorganized and mitochondrial abnormalized. Compared with the AMI model group, the blood-activating drug group and the combined administration group showed significant increase in the values of EF and FS (P < 0.05 or P < 0.01) and obvious reduction in LVIDd and LVIDs (P < 0.05 or P < 0.01), with the infarction area of left ventricular front wall up to about 40%-60%. The collagen deposition and myocardium fibrosis, the disorganized sarcomeres and mitochondrial abnormalities relieved significantly. And compared with blood-activating drug group, the combined administration group demonstrated further increase in the values of EF and FS and further decrease in LVIDd and LVIDs (P < 0.05), the collagen deposition and myocardium fibrosis, the disorganized sarcomeres and mitochondrial abnormalities relieved even more in Huoxue plus Anshen prescription group. CONCLUSION: The combined administration of blood-activating drug and sedative drug can further improve cardiac structure and function after myocardial ischemia infarction and have an obvious synergistic effect which may be related to sedative drug's effect of resisting lipid peroxide, stabling myocardial cell membrane and mitochondrial membrane and relieving cardiac cell injury.


Assuntos
Medicamentos de Ervas Chinesas/uso terapêutico , Hipnóticos e Sedativos/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Animais , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Infarto do Miocárdio/patologia , Ratos , Ratos Wistar
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