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1.
Phys Chem Chem Phys ; 19(9): 6563-6568, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28203661

RESUMO

The performance of Li-ion batteries relies heavily on the capacity and stability of constituent electrodes. Recently synthesized 2D silicene has demonstrated excellent Li-ion capacity with high charging rates. To explore the external influences for battery performance, in this work, first-principles calculations are employed to investigate the effect of external strain on the adsorption and diffusion of Li on silicene monolayers. It was found that tensile strain could enhance Li binding on silicene. The diffusion barrier is also calculated and the results show that Li diffusion through silicene is facilitated by tensile strain, whereas the strain has a limited effect on the energy barrier of diffusion parallel to the plane of pristine silicene. Our results suggest that silicene could be a promising electrode material for lithium ion batteries.

2.
Phys Chem Chem Phys ; 18(34): 23954-60, 2016 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-27523790

RESUMO

Graphynes, novel allotropic forms of carbon, have become a rising star in two-dimensional materials science due to the diverse geometric structures and excellent electronic properties. In this paper, first-principles calculations were performed to investigate a favorable path for successive hydrogenation of 14,14,14-graphyne and electronic properties of the resulting novel planar structure. Pairs of hydrogen atoms prefer to arrange themselves on opposite sides of acetylenic bonds within the basal plane due to the collective stabilization mediated by cooperative buckling of the original linear acetylenic chains. Progressive hydrogenation favors proceeding along linear directions in a row-by-row manner. A new strictly planar sp-sp(2)-bonded hydrocarbon is formed when half of the sp-hybridized carbon atoms in the chains are hydrogenated. In contrast to the zero-band-gap feature of pristine 14,14,14-graphyne, this hydrocarbon possesses a moderate direct band gap. A possible experimental realization of the proposed two-dimensional hydrocarbon was also discussed. This novel planar hydrocarbon material can not only broaden the application field of graphyne family in electronic and optoelectronic devices but also enrich the databases of carbon-based two-dimensional materials.

3.
Phys Chem Chem Phys ; 17(31): 20376-81, 2015 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-26194068

RESUMO

The energetic and electronic properties of acetylenic-bond-interconnected hexagonal boron nitride sheets (BNyne), in which the number of rows of BN hexagonal rings (denoted as BN width) between neighboring arrays of acetylenic linkages increases consecutively, have been explored using first-principles calculations. Depending on the spatial position of B/N atoms with respect to the acetylenic linkages, there are two different types of configurations. The band structure features and band gap evolutions of BNyne structures as a function of the BN width can be categorized into two families, corresponding to two distinct types of configurations. In particular, for both types of BNyne structures, the band gap variations exhibit odd-even oscillating behavior depending on the BN width, which is related to the different symmetries of acetylenic chains in the unit cell. These results suggest that the embedded linear acetylenic chains can provide more flexibility for manipulation of the atomic and electronic properties of hexagonal boron nitride. These sp-sp(2) hybrid structures might promise importantly potential applications for developing nanoscale electronic and optoelectronic devices.

4.
J Phys Chem A ; 119(14): 3458-70, 2015 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-25787719

RESUMO

Chirality, also called handedness, plays a crucial role in function ranging from biological self-assembly schemes, organic polymer functionalities, to optical material designs. In this Article, we demonstrated a first-principles investigation of chirality in magnetic AlMnAun(0/+1/-1) (n = 1-7) clusters. Optimized structures of the AlMnAun clusters exhibit configurational combinations between AlAun+1 and MnAun+1 clusters, indicating a subtle but equal competition between Au-Al and Au-Mn interactions in the alloy clusters. High magnetic moments are equal to or greater than 4µB in AlMnAun clusters due to the presence of the Mn dopant. Chirality turns up with the forms of right-handed and left-handed in stable AlMnAu5, AlMnAu6, and AlMnAu7 clusters. As a result, reflection symmetries are found in vibrational Raman and circular dichroism spectra of these chiral pairs. The present study shows that chiral magnetic clusters can be composed by doping two heteroatoms with one intrinsic magnetic dopant into small gold clusters.

5.
J Phys Chem A ; 119(49): 11922-7, 2015 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-26579836

RESUMO

New low-energy atomic structures and properties of medium-size gold nanoparticles (Au33-42) are studied, where the atomic positions of gold atoms are obtained on the basis of the generic formulation of shell and core concept. Hollow cage, tube-like, double-layered flat, fcc-like, and close-packed configurations are predicted. Relativistic density functional theory optimization indicated that low-symmetry stuffed configurations are all lower in energy than the others. Further analysis of the optimized structures of Au33-42 nanoparticles shows that these gold cores are all four-atom tetrahedral structures and similar to each other; only the number and positions of gold atoms at the surface of gold core are different. Compared with structure and electronic properties, Au33-42 nanoparticles have different structure stabilities and chemical activities. But they are all hybridizations of sp and d electrons. The obtained information forms the basis for future chemisorption studies to unravel the catalytic effects of gold nanoparticles.

6.
Heliyon ; 10(12): e33220, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-39021916

RESUMO

Seahorses are increasingly recognized for their nutritional potential, which underscores the necessity for comprehensive biochemical analyses. This study aims to investigate the fatty acid and amino acid compositions of eight seahorse species, including both genders of Hippocampus trimaculatus, Hippocampus kelloggi, Hippocampus abdominalis, and Hippocampus erectus, to evaluate their nutritional value. We employed Gas Chromatography-Mass Spectrometry (GC-MS) and High-Performance Liquid Chromatography (HPLC) to analyze the fatty acid and amino acid profiles of the seahorse species. GC-MS was used to detect 34 fatty acid methyl esters, while HPLC provided detailed amino acid profiles. GC-MS analysis demonstrated high precision with relative standard deviations (RSDs) generally below 2.53 %, satisfactory repeatability (RSDs from 6.55 % to 8.73 %), and stability (RSDs below 2.82 %). Recovery rates for major fatty acids ranged from 98.73 % to 109.12 %. HPLC analysis showed strong separation of amino acid profiles with theoretical plate numbers exceeding 5000. Precision tests yielded RSDs below 1.23 %, with reproducibility and stability tests showing RSDs below 2.73 % and 2.86 %, respectively. Amino acid recovery rates ranged from 97.58 % to 104.66 %. Nutritional analysis revealed significant variations in fatty acid content among the species. Female H. erectus showed higher levels of hexadecanoic acid and saturated fatty acids, while male H. abdominalis had lower concentrations of n-3 full cis 4,7,10,13,16,19-docosahexaenoic acid (DHA). Total lipid yields varied from 3.2491 % to 12.3175 %, with major fatty acids constituting 17.9717 %-74.6962 % of total lipids. In conclusion, this study provides essential insights into the fatty acid and amino acid composition of seahorses, supporting their potential as valuable dietary supplements. The differences between genders in specific fatty acids suggest a nuanced nutritional profile that could be exploited for targeted dietary applications. Further research is needed to explore the seasonal and environmental variations affecting seahorse biochemical composition.

7.
Small ; 9(20): 3506-13, 2013 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-23585395

RESUMO

The catalytic behavior of transition metals (Sc to Zn) combined in polymeric phthalocyanine (Pc) is investigated systematically by using first-principles calculations. The results indicate that CoPc exhibits the highest catalytic activity for CO oxidation at room temperature with low energy barriers. By exploring the two well-established mechanisms for CO oxidation with O2 , namely, the Langmuir-Hinshelwood (LH) and the Eley-Rideal (ER) mechanisms, it is found that the first step of CO oxidation catalyzed by CoPc is the LH mechanism (CO + O2 → CO2 + O) with energy barrier as low as 0.65 eV. The second step proceeds via both ER and LH mechanisms (CO + O → CO2 ) with small energy barriers of 0.10 and 0.12 eV, respectively. The electronic resonance among Co-3d, CO-2π*, and O2 -2π* orbitals is responsible for the high activity of CoPc. These results have significant implications for a novel avenue to fabricate organometallic sheet nanocatalysts for CO oxidation with low cost and high activity.

8.
J Phys Chem A ; 117(48): 13025-36, 2013 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-24224727

RESUMO

We demonstrated a first-principles investigation to search for magnetic superatoms in the vanadium-doped lithium clusters VLi(n) (n = 1-13). The stabilities of VLi(n) clusters were determined through geometrical and electronic optimizations. It is found that the growth pattern of VLi(n) in 3-space follows adding a Li atom capped on VLi(n-1) clusters. All doped clusters show larger relative binding energies compared with pure Li(n+1) partners and display tunable magnetic properties. When n = 8-13, the VLi(n) clusters adopt a cage-like structure with an endohedral V atom and are identified as superatoms with their magnetic moments successively decreasing from 5 to 0 µB. The isolated VLi8 superatom is emphasized due to its robust magnetic moment as well as high structural and chemical stability analogue of a single Mn(2+) ion. Molecular orbitals analysis shows that VLi8 has an electronic configuration of 1S(2)1P(6)1D(5), exhibiting Hund's filling rule of maximizing the spin-like atoms. Electronic shell structures of 1S(2) and 1P(6) are virtually unchanged in Li9 cluster as the V atom substitutes for the embedded Li atom, indicating that the electron-shell-closing model is valid for explaining its structures and stabilities. The results show that the tailored magnetic building blocks for nanomaterials can be formed by seeding magnetic dopants into alkali metal cluster cages.

9.
J Phys Chem A ; 116(6): 1493-502, 2012 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-22225504

RESUMO

The size-dependent electronic, structural, and magnetic properties of Mn-doped gold clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. A number of new isomers are obtained for neutral MnAu(n) (n = 1-16) clusters to probe the structural evolution. The two-dimensional (2D) to three-dimensional (3D) transition occurs in the size range n = 7-10 with manifest structure competitions. From size n = 13 to n = 16, the MnAu(n) prefers a gold cage structure with Mn atom locating at the center. The relative stabilities of the ground-state MnAu(n) clusters show a pronounced odd-even oscillation with the number of Au atoms. The magnetic moments of MnAu(n) clusters vary from 3 µ(B) to 6 µ(B) with the different cluster size, suggesting that nonmagnetic Au(n) clusters can serve as a flexible host to tailor the dopant's magnetism, which has potential applications in new nanomaterials with tunable magnetic properties.


Assuntos
Ouro/química , Fenômenos Magnéticos , Manganês/química , Isomerismo , Modelos Moleculares , Conformação Molecular , Reprodutibilidade dos Testes , Termodinâmica
10.
Eur J Pharmacol ; 908: 174349, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34284014

RESUMO

Accumulating evidence showed that berberine possessed the anti-inflammatory action in various diseases caused by inflammation. However, it was still unclear whether both inhalation and injection with berberine produced pulmonary protective role in acute respiratory distress syndrome (ARDS). This study was aimed to evaluate the effects of both administration routes including inhalation and injection with berberine in ARDS induced by lipopolysaccharide (LPS) inhalation. Histopathological examination and weight of lung were evaluated. Phosphorylation of NF-κB, JAK2 and STAT3 were measured to assess the activity of inflammation related signaling pathways. Proinflammatory cytokines including interleukin (IL)-1ß and tumor necrosis factor (TNF)-α in the bronchoalveolar lavage fluid (BALF) and serum were also detected. The results showed that LPS caused the lung injury, while both administration routes with berberine attenuated the injury and improved the pulmonary morphology. In addition, the primary TLR4/NF-κB and secondary JAK2/STAT3 signaling pathways which were activated by LPS in lung were totally inhibited by berberine administration. Moreover, proinflammatory cytokines in both BALF and serum were decreased by berberine. Considering that molecular docking simulation indicated that berberine could bind with TLR4, the present suggested that the inhibition of the inflammation related TLR4/NF-κB and JAK2/STAT3 signaling pathways might be involved in the pulmonary protective effect of berberine in LPS-induced ARDS.


Assuntos
NF-kappa B , Berberina , Lipopolissacarídeos , Simulação de Acoplamento Molecular , Receptor 4 Toll-Like
11.
Zhonghua Nan Ke Xue ; 16(9): 840-3, 2010 Sep.
Artigo em Zh | MEDLINE | ID: mdl-21171272

RESUMO

OBJECTIVE: To improve the diagnosis and treatment of paratesticular embryonal rhabdomyosarcoma (PER). METHODS: We retrospectively studied the clinical data of 5 cases of PER treated from 1997 to 2009 and reviewed the relevant literature, focusing on its clinical manifestations, diagnosis and treatment. RESULTS: The 5 cases of PER, 2 involving the spermatic cord, 2 the testis and 1 the tunica vaginalis, were all treated by radical orchiectomy. Pathologically, 2 cases were classified as stage I, 1 as stage II and 2 as stage IV. Postoperatively, 2 of the patients received chemotherapy and the other 3 refused adjunctive therapy. The patients were followed up for 6, 12, 18 and 28 months, respectively. Four of them remained free from relapse and metastasis, and 1 stage IV patient died of multiple metastasis at 6 months. CONCLUSION: Early diagnosis, radical orchiectomy and adjunctive chemo- or radio-therapy are effective means to the treatment of PER.


Assuntos
Rabdomiossarcoma Embrionário , Neoplasias Testiculares , Adolescente , Adulto , Humanos , Masculino , Estadiamento de Neoplasias , Estudos Retrospectivos
12.
ACS Omega ; 2(3): 1192-1197, 2017 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-31457497

RESUMO

As an improvement over organic or inorganic layered crystals, the synthetic monolayer ZnO(M) inherits semiconductivity and hostability from its bulk, yet it acts as a promising host for dilute magnetic semiconductors. Here, we report the electronic and magnetic properties of ZnO(M) doped with one 3d transition metal ion and simultaneously adsorbed with another 3d transition metal ion. Two sequences are studied, one where the dopant is fixed to Mn and the adsorbate is varied from Sc to Zn and another where the dopant and adsorbate are reversed. First-principles results show that the stable adsorbed-doped systems possess a lower bandgap energy than that of the host. System magnetic moments can be tuned to |5 - x|µB, where x refers to the magnetic moment of the individual 3d atom. An interplay between superexchange and direct exchange yields a ferromagnetic system dually adsorbed-doped with Mn. In addition to a novel material design route, the magnetic interaction mechanism is found beyond two dimensions, having been identified for its three-dimensional bulk and zero-dimensional cluster counterparts.

13.
Sci Rep ; 6: 19504, 2016 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-26776327

RESUMO

The inorganic layered crystal (ILC) MoS2 in low dimensions is considered as one of the most promising and efficient semiconductors. To enable the magnetism and keep intrinsic crystal structures, we carried out a first-principles study of the magnetic and semiconductive monolayer MoS2 adsorbed with the Mnn (n = 1-4) clusters, and bilayer MoS2 intercalated with the same clusters. Geometric optimizations of the Mnn@MoS2 systems show the complexes prefer to have Mnn@MoS2(M) pizza and Mnn@MoS2(B) sandwich forms in the mono- and bi-layered cases, respectively. Introductions of the clusters will enhance complex stabilities, while bonds and charge transfers are found between external Mn clusters and the S atoms in the hosts. The pizzas have medium magnetic moments of 3, 6, 9, 4 µB and sandwiches of 3, 2, 3, 2 µB following the manganese numbers. The pizzas and sandwiches are semiconductors, but with narrower bandgaps compared to their corresponding pristine hosts. Direct bandgaps were found in the Mnn@MoS2(M) (n = 1,4) pizzas, and excitingly in the Mn1@MoS2(B) sandwich. Combining functional clusters to the layered hosts, the present work shows a novel material manipulation strategy to boost semiconductive ILCs applications in magnetics.

14.
Int J Clin Exp Pathol ; 8(10): 13090-5, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26722505

RESUMO

OBJECTIVE: To investigate the expression and clinical significance of TRAP1 (tumor necrosis factor receptor-associated protein 1) in kidney cancer. METHODS: TRAP1 expression was detected in kidney cancer and normal kidney tissues by qRT-PCR and immunohistochemistry (IHC), respectively. Then, the correlation of TRAP1 expression with clinicopathological characters and patients' prognosis was evaluated in kidney cancer. RESULTS: IHC results revealed that the high-expression rates of TRAP1 in kidney cancer tissues and normal kidney tissues were 51.3% (41/80), 23.3% (7/30), and the difference was statistically significant (P=0.01). Also, TRAP1 mRNA level in kidney cancer was found to be significantly greater compared with those in normal kidney by qRT-PCR. In addition, TRAP1 expression in kidney cancer significantly correlated with lymph node metastasis and clinical stage (P<0.05). Kaplan-Meier survival analysis indicated that the mean survival time of patients with TRAP1 low-expression was significantly higher (56 months) than those patients with TRAP1 high-expression (47 months). Meanwhile, Kaplan-Meier and Cox survival analysis indicated that TRAP1, lymph node metastasis and clinical stage were correlated with patients' prognosis. CONCLUSION: TRAP1 is highly expressed in kidney cancer and correlates with patients prognosis, which may be served as a potential marker for the diagnosis and treatment of kidney cancer.


Assuntos
Biomarcadores Tumorais/análise , Proteínas de Choque Térmico HSP90/biossíntese , Neoplasias Renais/patologia , Idoso , Feminino , Proteínas de Choque Térmico HSP90/análise , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Neoplasias Renais/metabolismo , Neoplasias Renais/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Reação em Cadeia da Polimerase Via Transcriptase Reversa
15.
Nanoscale ; 3(9): 3743-6, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21804988

RESUMO

We theoretically studied the ferromagnetism/antiferromagnetism (FM/AFM) transition between single-wall carbon nanotubes (SWCNTs) induced by chemical modifications of semihydrogenation (SH-) and full-amination (NH(2)-). We found that armchairs with large diameters of SH-CNTs (n > 3) possess FM functions with intense magnetic moments, while armchair NH(2)-CNTs (n = 4, 6, 8) are antiferromagnetic semiconductors. The FM/AFM transition is mainly dominated by different chemical modifications and sizes of SWCNTs whose distance between carbon atoms of unpaired electrons can regulate the intensity of p-p spin interactions. Moreover, the zigzag SH-CNTs and NH(2)-CNTs are NM semiconductors. Thus, the electronic and magnetic properties of the SH- or NH(2)-CNTs can be precisely modulated by controlling the hydrogenation or amination on the different types and diameters of CNTs, which provides a new and also simple process for magnetism optimization design in SWCNTs.


Assuntos
Magnetismo , Nanotubos de Carbono/química , Aminação , Hidrogenação , Modelos Moleculares , Semicondutores
16.
Nanoscale ; 3(11): 4824-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21997243

RESUMO

Through first-principles calculations, we found doping carbon atoms onto BN monolayers (BNC) could significantly strengthen the Li bond on this material. Unlike the weak bond strength between Li atoms and the pristine BN layer, it is observed that Li atoms are strongly hybridized and donate their electrons to the doped substrate, which is responsible for the enhanced binding energy. Li adsorbed on the BNC layer can serve as a high-capacity hydrogen storage medium, without forming clusters, which can be recycled at room temperature. Eight polarized H(2) molecules are attached to two Li atoms with an optimal binding energy of 0.16-0.28 eV/H(2), which results from the electrostatic interaction of the polarized charge of hydrogen molecules with the electric field induced by positive Li atoms. This practical carbon-tuned BN-Li complex can work as a very high-capacity hydrogen storage medium with a gravimetric density of hydrogen of 12.2 wt%, which is much higher than the gravimetric goal of 5.5 wt % hydrogen set by the U.S. Department of Energy for 2015.


Assuntos
Compostos de Boro/química , Hidrogênio/isolamento & purificação , Lítio/química , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Absorção , Desenho de Equipamento , Análise de Falha de Equipamento , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
17.
J Phys Chem A ; 111(12): 2420-5, 2007 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-17388307

RESUMO

The geometries, stabilities, and electronic properties of Bn and AlBn clusters, up to n=12, have been systematically investigated by using the density-functional approach. The results of Bn clusters are in good agreement with previous conclusions. When the Al atom is doped in Bn clusters, the lowest-energy structures of the AlBn clusters favor two-dimensional and can be obtained by adding one Al atom on the peripheral site of the stable Bn when n

18.
J Chem Phys ; 127(23): 234312, 2007 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-18154387

RESUMO

The geometries, stabilities, and electronic and magnetic properties of Y(n)Al (n=1-14) clusters have been systematically investigated by using density functional theory with generalized gradient approximation. The growth pattern for different sized Y(n)Al (n=1-14) clusters is Al-substituted Y(n+1) clusters and it keeps the similar frameworks of the most stable Y(n+1) clusters except for Y(9)Al cluster. The Al atom substituted the surface atom of the Y(n+1) clusters for n<9. Starting from n=9, the Al atom completely falls into the center of the Y-frame. The Al atom substituted the center atom of the Y(n+1) clusters to form the Al-encapsulated Y(n) geometries for n>9. The calculated results manifest that doping of the Al atom contributes to strengthen the stabilities of the yttrium framework. In addition, the relative stability of Y(12)Al is the strongest among all different sized Y(n)Al clusters, which might stem from its highly symmetric geometry. Mulliken population analysis shows that the charges always transfer from Y atoms to Al atom in all different sized clusters. Doping of the Al atom decreases the average magnetic moments of most Y(n) clusters. Especially, the magnetic moment is completely quenched after doping Al in the Y(13), which is ascribed to the disappearance of the ininerant 4d electron spin exchange effect. Finally, the frontier orbitals properties of Y(n)Al are also discussed.

19.
J Chem Phys ; 126(23): 234704, 2007 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-17600432

RESUMO

The geometries, stabilities, and electronic properties of TiSin (n=2-15) clusters with different spin configurations have been systematically investigated by using density-functional theory approach at B3LYP/LanL2DZ level. According to the optimum TiSin clusters, the equilibrium site of Ti atom gradually moves from convex to surface, and to a concave site as the number of Si atom increases from 2 to 15. When n=12, the Ti atom in TiSi12 completely falls into the center of the Si outer frame, forming metal-encapsulated Si cages, which can be explained by using 16-electron rule. On the basis of the optimized geometries, various energetic properties are calculated for the most stable isomers of TiSin clusters, including the average binding energy, the highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO-LUMO) gap, fragmentation energy, and the second-order difference of energy. It is found that at size n=6,8,12 the clusters are more stable than neighboring ones. According to the Mulliken charge population analysis, charges always transfer from Si atoms to Ti atom. Furthermore, the HOMO-LUMO gaps of the most stable TiSin clusters are usually smaller than those of Sin clusters.

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