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1.
J Am Chem Soc ; 146(20): 13797-13804, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38722223

RESUMO

Hydrides are promising candidates for achieving room-temperature superconductivity, but a formidable challenge remains in reducing the stabilization pressure below a megabar. In this study, we successfully synthesized a ternary lanthanum borohydride by introducing the nonmetallic element B into the La-H system, forming robust B-H covalent bonds that lower the pressure required to stabilize the superconducting phase. Electrical transport measurements confirm the presence of superconductivity with a critical temperature (Tc) of up to 106 K at 90 GPa, as evidenced by zero resistance and Tc shift under an external magnetic field. X-ray diffraction and transport measurements identify the superconducting compound as LaB2H8, a nonclathrate hydride, whose crystal structure remains stable at pressures as low as ∼ half megabar (59 GPa). Stabilizing superconductive stoichiometric LaB2H8 in a submegabar pressure regime marks a substantial advancement in the quest for high-Tc superconductivity in polynary hydrides, bringing us closer to the ambient pressure conditions.

2.
Nanoscale ; 16(5): 2513-2521, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38205870

RESUMO

In recent years, van der Waals heterostructures (vdWHs) with controllable and peculiar properties have attracted extensive attention in the fields of electronics, optoelectronics, spintronics and electrochemistry. However, vdWHs with good thermoelectric performance are few due to the complex coupling of thermoelectric coefficients. Here, we employ density functional theory and Boltzmann's transport equation to explore the thermoelectric properties of the p-n vdWH of GaSe/SnS2, which has been experimentally observed to exhibit high performance as an optoelectronic device. We reveal that GaSe/SnS2 possesses strong anisotropy in terms of electronic transport resulting from the anisotropic carrier relaxation time. The longer carrier relaxation time in the y-direction for n-type induces a high power factor of 0.084 W m-1 K-2 at 300 K, while it is only 0.0087 W m-1 K-2) in the x-direction. The strong coupling of low-mid frequency phonon branches and the relatively weak Sn-S bond-induced anharmonicity hinder the phonon transport, which results in the lattice thermal conductivity of GaSe/SnS2 (14.61 and 15.43 W m-1 K-1 along the x- and y-directions at 300 K) being much smaller than the average value of GaSe and SnS2 (43.44 W m-1 K-1 at 300 K). The optimal thermoelectric figure of merit at 700 K for GaSe/SnS2 reaches 2.99, which is significantly higher than those of the constituents of GaSe (0.58) and SnS2 (1.04). The present work highlights the potential thermoelectric applications and the understanding of the thermoelectric transport mechanism for the recently synthesized p-n vdWH of GaSe/SnS2 with a high thermoelectric figure of merit and strong anisotropy.

3.
Nature ; 626(7997): 79-85, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38172640

RESUMO

Grain boundaries (GBs), with their diversity in both structure and structural transitions, play an essential role in tailoring the properties of polycrystalline materials1-5. As a unique GB subset, {112} incoherent twin boundaries (ITBs) are ubiquitous in nanotwinned, face-centred cubic materials6-9. Although multiple ITB configurations and transitions have been reported7,10, their transition mechanisms and impacts on mechanical properties remain largely unexplored, especially in regard to covalent materials. Here we report atomic observations of six ITB configurations and structural transitions in diamond at room temperature, showing a dislocation-mediated mechanism different from metallic systems11,12. The dominant ITBs are asymmetric and less mobile, contributing strongly to continuous hardening in nanotwinned diamond13. The potential driving forces of ITB activities are discussed. Our findings shed new light on GB behaviour in diamond and covalent materials, pointing to a new strategy for development of high-performance, nanotwinned materials.

4.
Nanoscale ; 15(46): 18910-18919, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-37975757

RESUMO

The emerging two-dimensional (2D) Janus systems with broken symmetry provide a new platform for designing ultrathin multifunctional spintronic materials. Recently, based on experimental monolayer MnSe2, ferromagnetism was predicted in Janus MnXY (X ≠ Y = S, Se, Te) monolayers; however, they exhibit low Curie temperatures and small magnetic anisotropic energies. To improve the Curie temperature and magnetic anisotropy, herein, we systemically explore the stability and electronic and magnetic properties of Janus MnSeTe and MnSTe monolayers under strain and carrier-doping using first-principles calculations and Monte Carlo simulations. It is found that both MnSeTe and MnSTe monolayers possess robustly high spin polarization with rational strain and carrier-doping. Both tensile strain and hole doping strengthen the ferromagnetic super-exchange interactions of the two nearest Mn atoms mediated by chalcogen atoms and exceedingly improve the perpendicular magnetic anisotropic energies (by up to 3.1 meV per f.u. for MnSeTe and 2.0 meV per f.u. for MnSTe). The Te-5p intraorbital hybridizations contributed to the main magnetic anisotropy. More remarkably, the tensile strain and hole doping collectively increase the Curie temperatures of MnSeTe and MnSTe to above and near room temperature (345 and 290 K, respectively). The present study reveals that Janus MnSeTe and MnSTe monolayers with robustly high spin polarization, room-temperature ferromagnetism and large perpendicular magnetic anisotropy are promising candidates for ultrathin multifunctional spintronic materials. This study will be of great interest for further experimental and theoretical explorations of 2D Janus manganese dichalcogenides.

5.
Nanoscale ; 15(22): 9843-9863, 2023 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-37222114

RESUMO

The exotic physicochemical properties of TM atom (3d, 4d, and 5d) embedded g-C4N3 as a novel class of 2D monolayers were systematically investigated through hierarchical high-throughput screening combined with spin-polarized first-principles calculations. After several rounds of efficient screening, 18 types of TM2@g-C4N3 monolayers with a TM atom embedded g-C4N3 substrate in large cavities on both sides in asymmetrical mode have been obtained. The effects of transition metal permutation and biaxial strain on the magnetic, electronic, and optical properties of TM2@g-C4N3 monolayers were comprehensively and deeply analyzed. By anchoring different TM atoms, various magnetic states including ferromagnetism (FM), antiferromagnetism (AFM), and nonmagnetism (NM) can be obtained. The Curie temperatures of Co2@ and Zr2@g-C4N3 are substantially improved up to 305 K and 245 K by applying -8% and -12% compression strains, respectively. This makes them promising candidates for low-dimensional spintronic device applications at or close to room temperature. Additionally, rich electronic states (metal, semiconductor, and half-metal) can be realized through biaxial strains or diverse metal permutations. Interestingly, the Zr2@g-C4N3 monolayer undergoes a transition of FM semiconductor → FM half-metal → AFM metal under biaxial strains from -12% to 10%. Notably, the embedding of TM atoms dramatically enhances visible light absorption compared to bare g-C4N3. Excitingly, the power conversion efficiency of the Pt2@g-C4N3/BN heterojunction can be as high as 20.20%, which has great potential in solar cell applications. This large class of 2D multifunctional materials provides a candidate platform to develop promising applications under different circumstances and is expected to be prepared in the future.

6.
Phys Chem Chem Phys ; 25(10): 7354-7365, 2023 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-36825532

RESUMO

Carbon-based magnetic molecular junctions are promising candidates for nanoscale spintronic applications because they are atomically thin and possess high stability and peculiar magnetism. Herein, based on first-principles and non-equilibrium Green's function, we designed a carbon-based molecular spintronic device composed of carbon atomic chains, zigzag-edged graphene nanoribbon (ZGNR), and a perylene molecule. Our results show that the device exhibits integrated spintronic and spin caloritronic functionalities, such as the bias-voltage driven spin filtering effect, negative differential resistance effect and giant magnetoresistance, temperature-gradient driven spin Seebeck effect, thermal spin filtering effect, high thermal magnetoresistance, and thermal colossal giant magnetoresistance. Furthermore, considering the phonon vibration effect, the spin and charge thermoelectric figure of merits (ZTsp and ZTch) can be enhanced and the peak of ZTsp is much larger than that of ZTch, indicating the excellent thermospin performance. The asymmetrical contact configuration between the carbon atomic chain and perylene/ZGNR inhibits the phonon thermal conductivity significantly, leading to the optimal ZTsp and ZTch of 2.4 and 0.5 at 300 K, respectively. These results suggest multifunctional spintronic and spin caloritronic applications for the perylene-based molecular device.

7.
J Phys Chem Lett ; 14(5): 1310-1317, 2023 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36724202

RESUMO

Boron-rich compounds have attracted much attention due to their interesting structures and excellent properties. Here, we performed an extensive study on the different B-P stoichiometries under pressure by combining a particle swarm optimization method with first-principles calculations. At 1 atm, BP and B6P are thermodynamically stable, while other stoichiometries are metastable. Under pressure, BP and B6P remain stable relative to constituent pure solids up to 80 GPa, while other stoichiometries become unstable at relatively low pressures. A new Cmca B6P is predicted with the lowest energy at 1 atm and shows higher shear strain than the R3̅m structure, which is known to be more resistant to brittle fracture than B4C. Moreover, the predicted Pm B8P is a magnetic semiconductor with a magnetic moment of 1 µB. All these boron-rich phosphides are hard materials. The present results enrich the B-P phase diagram and promote extensive research on their excellent properties.

8.
J Ethnopharmacol ; 303: 115996, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36509258

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Over 50 million adults in China suffer from angina pectoris, which are often treated with traditional Chinese medicine injections (TCMIs). However, the efficacies of TCMIs and conventional drugs as determined by randomized controlled trials (RCTs) were not rigorously compared with one another by network meta-analysis (NMA). This PRISMA-compliant NMA aimed to compare the efficacy and assess the evidence strengths of 24 TCMIs in treating adults with angina pectoris of RCTs. MATERIALS AND METHODS: Following the protocol (PROSPERO registration number CRD42018117720), the RCTs that compared any TCMI with another TCMI or conventional drug on outcome measures including symptomatic and electrocardiography improvements were included. The quality of included RCTs was assessed with the Cochrane's risk of bias 2 tool. Frequentist statistical analyses were performed, including NMA, pairwise meta-analysis (PMA), subgroup analysis, sensitivity analysis, meta-regression, and publication bias analysis. The certainty of evidence was assessed with the GRADE approach. RESULTS: Totally, 556 eligible RCTs with 57015 participants were identified while the quality of all but five included RCTs was poor. The significant efficacy estimates and insignificant heterogeneity assessment from PMA and NMA indicated that nearly all TCMIs were more efficacious than conventional treatments for angina pectoris. Adequate subgroup and sensitivity analyses found the robust and consistent results. However, the evidence strengths of meta-analyses were assessed as very low to low due to the high risk of RCTs. The comprehensive efficacy estimates suggested that 4 TCMIs (HH, Honghua injection; HHH, Honghua Huangsesu injection; GLP, Gualoupi injection; and SM, Shenmai injection) was the best anti-anginal drugs for adults with angina pectoris. CONCLUSION: TCMIs appear to be efficacious for angina pectoris, although evidence evaluation of high-quality RCTs of TCMIs would be necessary. In particular, randomization and blinding procedures of the RCTs should be explicated to meet the CONSORT requirements.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Adulto , Humanos , Angina Pectoris/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Metanálise em Rede , Ensaios Clínicos Controlados Aleatórios como Assunto
9.
Phys Chem Chem Phys ; 25(3): 1632-1641, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36305285

RESUMO

How to effectively tune 2D electronic and magnetic properties is key to developing novel spintronic materials and devices. Although the strain induced metal-to-half-metal electronic phase transition (EPT) has been studied in 2H NbSe2 and NbS2 monolayers, the 1T phase, the Coulomb interaction and the transport properties have not been explored. Here, using first-principles calculations in junction with nonequilibrium Green's function, we present a comprehensive and comparative study on the strain tuned structural, electronic, magnetic and thermal spin transport properties for NbSe2 and NbS2 monolayers with and without Coulomb interaction. It is found that the Coulomb interaction makes the strain induced 2H-to-1T structural phase transition easier. Similar to the 2H phase, there is also a strain induced metal-to-half-metal EPT for the 1T phase without Coulomb interaction, and the Coulomb interaction makes the ETP easier. Remarkably, the 2H-NbSe2 monolayer with Coulomb interaction is a bipolar spin gapless semiconductor (SGS), and novel Dirac half-metal and usually SGS can be obtained by the tensile strain. In addition, we predict the excellent spin Seebeck effect and thermal spin diode effect in the bipolar SGS of the 2H-NbSe2 monolayer with Coulomb interaction, and expect the spin filtering effect and high magnetoresistance in the half-metals driven by the strain. We also discuss the strength of Coulomb interaction by comparing the theoretical and available experimental electronic states, indicating the indispensability of Coulomb interactions. These results suggest that 2D NbSe2 and NbS2 are promising candidates for phase-change spintronic materials and devices, and will stimulate extensive studies on this class of 2D systems.

10.
Adv Mater ; 35(50): e2204375, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36099908

RESUMO

The observation of fracture behaviors in perfect and twinned B4 C crystals via in situ transmission electron microscopy (TEM) mechanical testing is reported. The crystal structure of the synthesized B4 C, composed of B11 C icosahedra connected by boron-deficient C-▫-C chains in a chemical formula of B11 C3 , is determined by state-of-the-art aberration-corrected scanning TEM. The in situ TEM observations reveal that cracking is preferentially initiated at the twin boundaries (TBs) in B4 C under both indentation and tension loading. The cracks then propagate along the TBs, thus resulting in the fracture of B4 C. These results are consistent with the theoretical calculations that show that TBs have a softening effect on B4 C with amorphous bands preferentially nucleated at the TBs. These findings elucidate the atomic arrangement and the role of planar defects in the failure of B4 C. Furthermore, they can guide the design of advanced superhard materials via planar defect control.

11.
Phys Chem Chem Phys ; 24(40): 24917-24923, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36200432

RESUMO

Based on first-principles calculations in combination with the Boltzmann transport theory, we investigate the effects of onsite Coulomb interaction and strain on the lattice thermal conductivity of the KAgSe monolayer, a recently discovered 2D thermoelectric system with a low lattice thermal conductivity when the onsite Coulomb interaction was not considered (X. Zhang, C. Liu, Y. Tao, Y. Li, Y. Guo, Y. Chen, X. C. Zeng and J. Wang, Adv. Funct. Mater., 2020, 30, 2001200). Our calculations reveal that the onsite Coulomb interaction leads to an increase in the lattice thermal conductivity from 1.22 to 1.82 W m-1 K-1 at room temperature due to the increased phonon group velocity and relaxation time. However, with onsite Coulomb interaction, small 3% biaxial tensile strain can give rise to a 75% considerable decrease in the lattice thermal conductivity at room temperature, from 1.82 to 0.45 W m-1 K-1, which is also much lower than the lattice thermal conductivity of 1.22 W m-1 K-1 without onsite Coulomb interaction and strain. The strain induced decrease of phonon group velocity and enhancement of lattice anharmonicity (large Grüneisen parameter and phase space volume) are responsible for the reduced lattice thermal conductivity. The present work highlights that the onsite Coulomb interaction is indispensable when determining the lattice thermal conductivity of 2D KAgSe, and small tensile strain can greatly decrease the lattice thermal conductivity.

12.
Phys Chem Chem Phys ; 24(33): 19734-19742, 2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-35946496

RESUMO

Reconfigurable magnetic tunnel diodes have recently been proposed as a promising approach to decrease the base collector leakage currents. However, conventional bulk interfaces usually suffer from strong Fermi level pinning, making it difficult to miniaturize spintronic devices. Fortunately, 2D van der Waals (vdW) systems with ultra-clean interfaces and without dangling bonds can solve this problem. Inspired by the recently discovered novel electronic states of type-II spin gapless semiconductor in 2D VSi2P4 and half-metal in 2D FeCl2, we propose the VSi2P4/FeCl2 vdW heterostructure, and investigate the interface Schottky barrier and the bias-voltage-dependent spin transport properties by using density functional theory and the nonequilibrium Green's function. The most stable vdW interface is determined from the possible twelve interfaces with different stacking sequences and rotation angles. The interface Schottky barrier is beneficial to electrons moving in the spin-down channel due to the Ohmic contact. The heterostructure exhibits a huge rectification ratio (up to 2.9 × 105%) and an excellent spin filtering effect with zero threshold bias voltage, which are explained in terms of the spin-dependent band structure, transmission spectrum and transmission path. These results indicate the promising applications of the VSi2P4/FeCl2 vdW heterostructure as a 2D reconfigurable magnetic diode and a spin filter with miniaturization and low energy consumption.

13.
Nanoscale ; 14(21): 7891-7897, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35587036

RESUMO

2D van der Waals magnets have been widely studied in spintronics because of their unique electronic properties, no dangling bonds, and ultra-clean interfaces. However, most of them possess low Curie temperatures. Motivated by the recent discovery of a near-room-temperature ferromagnetic semiconductor in monolayer GdI2, we proposed the Au/GdI2/Au vertical van der Waals junction and investigated the bias-voltage- and temperature-gradient-dependent spin transport characteristics using density functional theory and the non-equilibrium Green's function method. It is found that, like bulk GdI2, the four-layer GdI2 in the central scattering region of the junction exhibits intralayer ferromagnetism with weak interlayer antiferromagnetic coupling. An almost 100% spin polarization can be obtained whether at a bias voltage or at a temperature gradient for the junction, while high tunneling magnetoresistances are observed in a large bias voltage range or in a large temperature gradient range, which can reach 29000% and 3600%, respectively. The junction also exhibits a thermal spin diode effect. These versatile bias voltage- and temperature gradient-driven spin transport properties are understood from the calculated spin-dependent band structure of layered GdI2 and the spin-dependent transmission spectrum and density of states of the junction. The present work highlights layered GdI2 as a promising magnetic tunnel barrier for van der Waals spintronic devices and spin caloritronic devices.

14.
Small ; 18(22): e2201212, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35396819

RESUMO

Superhard materials other than diamond and cubic boron nitride have been actively pursued in the past two decades. Cubic silicon carbide, i.e., ß-SiC, is a well-known hard material with typical hardness <30 GPa. Although nanostructuring has been proven to be effective in enhancing materials' hardness by virtue of the Hall-Petch effect, it remains a significant challenge to improve hardness of ß-SiC beyond the superhard threshold of 40 GPa. Here, the fabrication of nanocrystalline ß-SiC bulks is reported by sintering nanoparticles under high pressure and high temperature. These ß-SiC bulks are densely sintered with average grain sizes down to 10 nm depending on the sintering conditions, and the Vickers hardness increases with decreasing grain size following the Hall-Petch relation. Particularly, the bulk sintered under 25 GPa and 1400 °C shows an average grain size of 10 nm and an asymptotic Vickers hardness of 41.5 GPa. Boosting the hardness of ß-SiC over the superhard threshold signifies an important progress in superhard materials research. A broader family of superhard materials is in sight through successful implementation of nanostructuring in other hard materials such as BP.

15.
Phys Chem Chem Phys ; 24(5): 3296-3302, 2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35050286

RESUMO

Ultralow lattice thermal conductivity is crucial for achieving a high thermoelectric figure of merit for thermoelectric applications. In this work, using first-principles calculations and the phonon Boltzmann transport theory, we investigate the phonon thermal transport properties of 2D KCuSe. Our calculations indicate that the strong acoustic-optical coupling, the low-lying acoustic phonon modes and the strong lattice anharmonic effect with a large Grüneisen parameter and phase space volume result in an ultralow lattice thermal conductivity of 0.021 W m-1 K-1 at 300 K for monolayer KCuSe, which is lower than those of recently reported KAgSe (0.26 W m-1 K-1 at 300 K) and TlCuSe (0.44 W m-1 K-1 at 300 K). Importantly, although the Coulomb interactions and the tensile biaxial strain lead to the increase of lattice thermal conductivity due to the increasing relaxation time (0.056 and 0.28 W m-1 K-1 at 300 K without and with 6% tensile strain, respectively), it is still lower than those of most 2D thermoelectric materials. The advantages of being cheap, environmentally friendly and having low lattice thermal conductivity compared to the KAgSe and TlCuSe derivatives make KCuSe a promising candidate for thermoelectric applications, which will stimulate more efforts toward theoretical and experimental studies on this class of 2D ternary semiconductors.

16.
Natl Sci Rev ; 9(1): nwab140, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35070330

RESUMO

Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp 2 and sp 3). Exploring new forms of carbon has been the eternal theme of scientific research. Herein, we report on amorphous (AM) carbon materials with a high fraction of sp 3 bonding recovered from compression of fullerene C60 under high pressure and high temperature, previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5-2.2 eV, comparable to that of widely used AM silicon. Comprehensive mechanical tests demonstrate that synthesized AM-III carbon is the hardest and strongest AM material known to date, and can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.

17.
Molecules ; 26(21)2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34770785

RESUMO

Although some atomically thin 2D semiconductors have been found to possess good thermoelectric performance due to the quantum confinement effect, most of their behaviors occur at a higher temperature. Searching for promising thermoelectric materials at room temperature is meaningful and challenging. Inspired by the finding of moderate band gap and high carrier mobility in monolayer GeP3, we investigated the thermoelectric properties by using semi-classical Boltzmann transport theory and first-principles calculations. The results show that the room-temperature lattice thermal conductivity of monolayer GeP3 is only 0.43 Wm-1K-1 because of the low group velocity and the strong anharmonic phonon scattering resulting from the disordered phonon vibrations with out-of-plane and in-plane directions. Simultaneously, the Mexican-hat-shaped dispersion and the orbital degeneracy of the valence bands result in a large p-type power factor. Combining this superior power factor with the ultralow lattice thermal conductivity, a high p-type thermoelectric figure of merit of 3.33 is achieved with a moderate carrier concentration at 300 K. The present work highlights the potential applications of 2D GeP3 as an excellent room-temperature thermoelectric material.

18.
Artigo em Inglês | MEDLINE | ID: mdl-34603462

RESUMO

OBJECTIVE: The effects of apelin-13 on the expression of Bcl-2 and caspase-3 factors and the apoptosis of adipocytes were studied at the cellular and animal levels. METHODS: 3T3-L1 preadipocytes were cultured and grouped. The third-generation cells were added to the control DMSO solvent and amidation-modified apelin-13. The expression of Bcl-2 and caspase-3 were detected. The cell growth viability and cell apoptosis were detected. DOI model rats were established. The effects of apelin-13 on DOI rat biochemical indicators, the expression of Bcl-2, caspase-3, and cell apoptosis were investigated by injecting amidation-modified apelin-13 through the tail vein. RESULT: In in vitro experiments, amidation-modified apelin-13 can significantly reduce the growth viability of adipocytes and the expression of Bcl-2, increase the expression of caspase-3, and promote the apoptosis of adipocytes. Animal experiments also show that apelin-13 modified by amidation can adjust the abnormal biochemical indicators of DOI rats, decrease the expression of Bcl-2 in adipose tissue, increase the expression of caspase-3, and promote the apoptosis of adipocytes. CONCLUSION: Amidation of apelin-13 can promote fat cell apoptosis and reduce the incidence of obesity. The mechanism may be accomplished by inhibiting Bcl-2 and caspase-3 factors. This study helps us understand the effect of apelin-13 on fat cell apoptosis and hopes to provide a basis for the development of antiobesity drugs.

19.
Transl Lung Cancer Res ; 10(6): 2573-2587, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34295663

RESUMO

BACKGROUND: Patients with non-small cell lung cancer (NSCLC) complicated with chronic obstructive pulmonary disease (COPD) with poor performance status (PS) are common in clinical practice with few related studies. Present studies have found that weekly low-dose docetaxel or gemcitabine combined with platinum is suitable for elderly or poor PS patients with advanced NSCLC. METHODS: Untreated advanced driver mutation-negative NSCLC patients with COPD and PS ≥2 were enrolled in this double-blind randomized trial. Both groups controlled their COPD symptoms according to the GOLD guidelines. The anti-tumor regimens included docetaxel (37.5 mg/m2, D1, D8)/carboplatin (AUC 5.0) (DC group) and gemcitabine (1,000 mg/m2, D1, D8)/carboplatin (AUC 5.0) (GC group) were used every 3 weeks with continuous chemotherapy for 4-6 cycles or until disease progression. The primary endpoints were progression-free survival (PFS), and overall survival (OS). RESULTS: Among the 52 patients (DC, n=25; GC, n=27), the median follow-up time was 12.3 months. There was no significant difference in tumor overall response rate (ORR; DC, 20.0% vs. GC, 22.2%, P=0.845) and disease control rate (DCR; DC, 72.0% vs. GC, 74.1%, P=0.064) between the 2 groups. The median PFS (GC, 6.5 vs. DC, 5.5 months; P=0.296) and the median OS (GC, 14.9 vs. DC, 12.3 months; P=0.548) of the GC group was slightly longer than the DC group. The main adverse reactions were myelosuppression and there were few adverse reactions of grade 3-4. Compared with the anti-tumor therapy only group in previous literature, the median PFS in this study was longer (6.2 months, 95% CI: 3.533-6.733 vs. 3.5 months, 95% CI: 2.432-4.568; P=0.589). There was also no significant difference in median OS and median PFS between the 2 groups (14.0 vs. 15.0 months, P=0.718). Chemotherapy cycle (P<0.001) was an independent prognostic factor for PFS, while chemotherapy cycle (P=0.011) and PS (P=0.041) were independent prognostic factors for OS. CONCLUSIONS: Weekly low-dose docetaxel or gemcitabine combined with carboplatin chemotherapy regimens can yield survival benefits and a tolerable safety profile in patients with driver mutation-negative advanced NSCLC and poor PS complicated with COPD, with no significant difference between the two regimens. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-IPR-15006164.

20.
Bioinorg Chem Appl ; 2021: 3594630, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34054938

RESUMO

With the adjustment of human diet and lifestyle changes, the prevalence of obesity is increasing year by year. Obesity is closely related to the excessive accumulation of white adipose tissue (WAT), which can synthesize and secrete a variety of adipokines. Apelin is a biologically active peptide in the adipokines family. Past studies have shown that apelin plays an important regulatory role in the pathogenesis and pathophysiology of diseases such as the cardiovascular system, respiratory system, digestive system, nervous system, and endocrine system. Apelin is also closely related to diabetes and obesity. Therefore, we anticipate that apelin-13 has an effect on lipometabolism and intend to explore the effect of apelin-13 on lipometabolism at the cellular and animal levels. In in vitro experiments, amidation-modified apelin-13 can significantly reduce the lipid content; TG content; and the expression of PPARγ, perilipin mRNA, and protein in adipocytes. Animal experiments also show that amidation modification apelin-13 can improve the abnormal biochemical indicators of diet-induced obesity (DOI) rats and can reduce the average diameter of adipocytes in adipose tissue, the concentration of glycerol, and the expression of PPARγ and perilipin mRNA and protein. Our results show that apelin-13 can affect the metabolism of adipose tissue, inhibit adipogenic differentiation of adipocytes, promote lipolysis, and thereby improve obesity. The mechanism may be regulating the expression of PPARγ to inhibit adipogenic differentiation and regulating the expression of perilipin to promote lipolysis. This study helps us understand the role of apelin-13 in adipose tissue and provide a basis for the elucidation of the regulation mechanism of lipometabolism and the development of antiobesity drugs.

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