Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 61
Filtrar
Mais filtros










Base de dados
Tipo de estudo
Intervalo de ano de publicação
1.
Zhongguo Zhong Yao Za Zhi ; 44(15): 3233-3238, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31602877

RESUMO

In order to study the correlation between the traits of Andrographis paniculata. The main agronomic traits and the content of four kinds of diterpene lactons were measured by the seedlings and the unmutagenized seeds carried by the spacecraft,and multiple comparisons,correlations and principal component analysis were carried out. The results showed that the agronomic traits of A. paniculata have different degrees of difference after being carried by space. The contents of diterpene lactones were quite different. The variation coefficients of deoxyandrographolide content,fresh weight,leaf dry weight,dehydrated andrographolide content,dry weight,neoandrographolide content and andrographolide content were all over 35%. There was a significant correlation between multiple traits,and the leaf weight ratio was significantly positively correlated with the number of primary tillers,leaf dry weight and dry weight,and was significantly negatively correlated with the content of deoxyandrographolide. Andrographolide content was a significantly negatively correlated with the number of leaves and the number of primary tillers,and positively correlated with the other three lactones. Five principal components were extracted from principal component analysis,and the cumulative contribution rate was 83. 127%,which were yield factor,plant type factor,leaf type factor,component factor and seed weight factor. Among the traits affecting the quality of A. paniculata,the yield factor for reliability of the selection of A. paniculata is higher than other factors. There are abundant variations among the traits of A. paniculata,carried in space which increase the genetic diversity. The principal component analysis method can be used to select the principal component factors according to the breeding requirements,which provides a theoretical basis for the breeding of high-yield and high-quality A. paniculata and the high-yield and stable cultivation of A. paniculata.


Assuntos
Andrographis/química , Diterpenos/análise , Lactonas/análise , Compostos Fitoquímicos/análise , Folhas de Planta , Reprodutibilidade dos Testes
2.
Chin Med J (Engl) ; 132(17): 2141-2142, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31433329
4.
J Mol Model ; 25(8): 212, 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280370

RESUMO

In the present study, DFT calculations are carried out on domestically designed 7-methyl-2-phenyl-5'H-spiro[chromene-4,2'-chromeno[3,4-e][1,3]oxazin]-5'-one spiropyran and merocyanine derivatives to recognize alkali and alkaline earth metal ions. Detection of these metal ions can be attained by exploiting the variation of the second-order nonlinear optical properties. Merocyanine forms of these derivatives exhibit the ability to complex with different metal ions (Li+, Na+, K+, and Ca2+), which is associated with large contrasts in the hyper-Rayleigh scattering (HRS) response as a function of metal size and charge. Interestingly, in this study, Mero-Li+ shows significant nonlinear optical response with dynamic HRS first hyperpolarizability amounting to 7607 a.u., which is about nine times higher than its corresponding spiro form (846 a.u.) at the CAM-B3LYP/6-311G* level of theory. The present investigation clarifies the effect of metal nature on the enhancement of the first hyperpolarizability between the closed and open forms of the studied coumarin derivatives. Graphical abstract The coumarin-based compound 3 demonstrate the higher second-order NLO responses as a function of metal cation size and charges. Complexation of smaller alkali metal ions leads to the formation of stronger metal-ligand bonds, larger geometrical relaxations and significant enhancement of the HRS first hyperpolarizabilities. This present investigation elucidates the effect of metal nature on the enhancement of the first hyperpolarizability between the closed and open forms of studied coumarin derivatives.

6.
Chemphyschem ; 20(14): 1879-1884, 2019 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-31124269

RESUMO

The nature of the 2e/12c bond and its conversion to a carbon-carbon single bond in phenalenyl dimers have prompted a great deal of interests recently. In this work, we theoretically investigated a series of π-stacking phenalenyl derivatives with 2e/12c bonding character by density functional theory (DFT) calculations to elucidate origin of this unusual bond conversion. Results show that bond-conversion of the phenalenyl dimer easily occurs at room-temperature both dynamically and thermodynamically. However, bond-conversion of hetero π-stacking adducts, in which the two center carbon atoms were substituted by boron and nitrogen atoms, respectively, is much more difficult, because the 2e/12c bond is stabilized by its charge transfer character. Consequently, the bond-conversion is an endothermic process, albeit with a low conversion barrier. Interestingly, Lewis acid-base interactions would be induced by substitution of the center nitrogen atom to phosphorus atom. The 2e/12c bond is further stabilized by 5.9 kcal mol-1 and its conversion is also thermodynamically unfavorable.

7.
J Comput Chem ; 40(19): 1772-1779, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30942507

RESUMO

Usually, an extra catalyst (for example, the transition metal complexes) need to be used in catalyzing hydroboration, which involved the cost, environment, and so forth. Here, a greener and controllable catalyst-external electric field (EEF) was used to study its effect on hydroboration of N-(4-methylbenzyl)aniline (PhN═CHPhMe) with pinacolboane (HBPin). The results demonstrated that EEF could affect the barrier heights of both two pathways of this reaction. More significantly, flipping the direction of EEF could modify the reaction mechanism to induce a dominant inverse hydroboration at some field strength. That is to say, oriented EEF is a controlling switch for the anti- or Markovnikov hydroboration reaction of imines. This investigation is meaningful for the exploration of greener catalyst for chemistry reaction and guide a new method for the Markovnikov hydroboration addition. © 2019 Wiley Periodicals, Inc.

8.
Mol Neurobiol ; 56(5): 3522-3537, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30143969

RESUMO

Alzheimer's disease (AD) represents a progressive neurodegenerative disorder characterized by distinctive neuropathological changes. Recently, long noncoding RNAs (lncRNAs) have become a key area of interest due to their potential in AD therapy. Hence, the aim of the current study was to investigate the effect of lncRNA SOX21-AS1 on neuronal oxidative stress injury in mice with AD via the Wnt signaling pathway by targeting FZD3/5. Microarray analysis was performed to screen AD-related differentially expressed genes (DEGs). Following verification of the target relationship between SOX21-AS1 and FZD3/5, the contents of OH-, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were determined, with the expressions of SOX21-AS1, FZD3/5, ß-catenin, cyclin D1, and 4-HNE in hippocampal neuron cells subsequently detected. Cell cycle distribution and apoptosis were evaluated. Bioinformatics analysis revealed that SOX21-AS1 was upregulated in AD, while highlighting the co-expression of SOX21-AS1 and FZD3/5 genes and their involvement in the Wnt signaling pathway. AD mice exhibited diminished memory and learning ability, increased rates of MDA, OH-, SOX21-AS1, 4-HNE, and elevated levels of hippocampal neuron cell apoptosis, accompanied by decreased levels of SOD, CAT, GSH-Px, FZD3/5, ß-catenin, and cyclin D1. Silencing of SOX21-AS1 resulted in decreased OH-, MDA contents, SOX21-AS1, and 4-HNE, and increased SOD, CAT, GSH-Px, FZD3/5, ß-catenin, and cyclin D1, as well as reduced apoptosis of hippocampal neuron cells. Taken together, the key findings of the present study demonstrated that silencing of lncRNA SOX21-AS1 could act to alleviate neuronal oxidative stress and suppress neuronal apoptosis in AD mice through the upregulation of FZD3/5 and subsequent activation of the Wnt signaling pathway.


Assuntos
Doença de Alzheimer/genética , Receptores Frizzled/genética , Inativação Gênica , Neurônios/patologia , Estresse Oxidativo/genética , RNA Longo não Codificante/genética , Regulação para Cima/genética , Via de Sinalização Wnt/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Apoptose/genética , Sequência de Bases , Pontos de Checagem do Ciclo Celular/genética , Feminino , Células HEK293 , Hipocampo/patologia , Hipocampo/ultraestrutura , Humanos , Masculino , Memória , Camundongos , Neurônios/metabolismo , RNA Longo não Codificante/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fase S/genética
9.
Phys Chem Chem Phys ; 21(1): 18-21, 2018 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-30516762

RESUMO

Generally, the hydroboration of benzonitrile produces B-N containing compounds. However, an unprecedented B-C bond may be formed in the presence of a suitable external electric field (EEF). In reactions of benzonitrile with borane, when the EEF is oriented parallel to the positive direction (N → C) of the N[triple bond, length as m-dash]C bond, the barriers to Markovnikov hydroboration are decreased gradually, meaning the pathway for generating B-C bonds becomes more favorable. Accordingly, hydroboration could be influenced and its selectivity could be controlled by changing the magnitude and direction of an applied EEF.

10.
Chemistry ; 24(63): 16919-16924, 2018 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-30211451

RESUMO

Stable phenalenyl (PLY) radical π-dimers still play an important role for new multifunctional materials owing to their intriguing molecular structure and unusual pancake π-π bonding mode. Herein, we design a new biphenalenyl biradicaloid (1) consisting of two PLYs and one benzene ring linkage tethered by single bonds, which presents an open-shell character. Further, three π-dimers (a1, b1, and c1) combined with 1 and conventional biphenalenyl biradicaloid (a, b, and c), which are capable of forming two staggered PLY dimers, exhibiting a short interlayer distance between the monomers. Interestingly, the analysis of the frontier molecular orbital reveals that two bonding orbitals, namely, the two highest occupied molecular orbitals (HOMO and HOMO-1) are doubly occupied. The results reveal that three π-dimers display two parallel pancake bonds. Moreover, they have small diradical and tetraradical characters, large interaction energies, and strong aromaticity, which indicate the stability of these π-dimers. The present work creates a new class of strong pancake bonding and might be utilized in devising an array of materials.

11.
Zhongguo Zhong Yao Za Zhi ; 43(13): 2747-2750, 2018 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-30111026

RESUMO

Immunogenic antigen (spinosin-BSA) and coating antigen (spinosin-OVA) of spinosin were synthesized by sodium periodate oxidation method. UV scanning analysis method showed that these two spinosins were successfully conjugated with carrier protein and the coupling ratio was 17 and 13.7, respectively. Meanwhile, when immunized by spinosin-BSA,the mice can produce anti-spinosin antibodies with the high titer (1:32 000),specificity (IC50 211.6 µg·L⁻¹) and low cross-reaction rate measured by ELISA tests. The artificial antigen of spinosin was successfully synthesized, which can be applied for preparation of monoclonal antibodies and establishment of appropriate immune method.


Assuntos
Flavonoides/química , Animais , Antígenos , Ensaio de Imunoadsorção Enzimática , Camundongos , Vacinas Sintéticas
13.
Phys Chem Chem Phys ; 20(27): 18699-18706, 2018 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-29956706

RESUMO

An interesting biphenalenyl biradicaloid (IDPL) dimer consisting of both-middle superimposed phenalenyls and both-end nonsuperimposed phenalenyls has been synthesized, and has attracted intensive research interest due to its intra- and intermolecular interactions and semiconductive characteristics. It is significant that under regulation of the external electric field the directional charge transfer (CT) can produce attractive properties. In the present work, the structure and electronic properties of the IDPL dimer under an external electric field (along the horizontal Fx or the vertical Fz directions) are explored, and the following properties determined: (i) as the horizontal Fx increases, the intramolecular CT becomes larger, which induces the intermolecular CT of the IDPL dimer. (ii) In contrast, as the vertical Fz increases, the large intermolecular CT gives rise to the intramolecular CT of the IDPL dimer. (iii) More importantly, the external electric field effectively regulates and controls the first hyperpolarizability (ßtot) of the IDPL dimer. Compared with the vertical Fz, the horizontal Fx induces a larger first hyperpolarizability (ßtot = 5.48 × 105 a.u.). Furthermore, the application of a uniform external electric field (Fx,y,z) to the IDPL dimer was investigated to define the external electric field direction of the material application. The ßtot values were increased with increasing of the uniform Fx,y,z. Our study provides an effective strategy for developing high-performance NLO materials by tuning the external electric field, and could be of significance for application in switch devices.

14.
Neurochem Int ; 112: 197-205, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28736242

RESUMO

Neuronal death after traumatic brain injury (TBI) is a complex process resulting from a combination of factors, many of which are still unknown. Transient receptor potential melastatin 7 (TRPM7) is a transient receptor potential channel that has been demonstrated to mediate ischemic and traumatic neuronal injury in vitro. In the present study, TRPM7 was suppressed in the rat cerebral cortex by intracortical injections of viral vectors bearing shRNA specific for TRPM7 to investigate its potential role in an in vivo TBI model. We found that TRPM7 suppression significantly reduced brain edema, brain contusion volume and motor functional deficits, which was sustained for at least 2 weeks after the insult. These protective effects were accompanied by inhibited apoptosis in injured cortex. Also, TRPM7 suppression attenuated lipid peroxidation, decreased the expression of protein carbonyl, and preserved the endogenous antioxidant enzyme activities. The results of western blot analysis showed that TRPM7 suppression markedly increased the phosphorylation of Akt and endothelial nitric oxide synthase (eNOS). In addition, blocking Akt/eNOS pathway activation by the specific inhibitor LY294002 (LY, 10 µL, 10 mmol/L) or L-NIO (0.5 mg/kg) partially reversed the protective effects of TRPM7 suppression and its anti-oxidative activities. Taken together, these findings demonstrated that regional inhibition of TRPM7 in cerebral cortex exerts neuroprotective effects against TBI through activation of Akt/eNOS pathway. Thus, TRPM7 might represent a potential drug development target for the treatment of TBI.


Assuntos
Lesões Encefálicas Traumáticas/metabolismo , Córtex Cerebral/metabolismo , Estresse Oxidativo/fisiologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Canais de Cátion TRPM/metabolismo , Animais , Lesões Encefálicas Traumáticas/patologia , Lesões Encefálicas Traumáticas/prevenção & controle , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , RNA Interferente Pequeno/farmacologia , Ratos , Ratos Sprague-Dawley , Canais de Cátion TRPM/antagonistas & inibidores
15.
Neurosci Lett ; 664: 107-109, 2018 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-29138090

RESUMO

Miyoshi myopathy (MM) is an autosomal recessive distal muscular dystrophy caused by mutations in the dysferlin gene (DYSF), a 150-kb gene on chromosome 2p13 that contains 55 coding exons. Many patients with MM harbour mutations in the DYSF gene, and most of these mutations are inherited from the patients' parents. Recently, we encountered novel, de novo mutations in the DYSF gene in a patient with MM. DYSF gene analysis was performed by targeted next-generation sequencing, and we found that the patient had compound heterozygous mutations, including a de novo mutation (c.613C > T) in exon 6 and a novel missense mutation (c.968T > C) in exon 11. The novel missense mutation, predicted to be a disease-causing mutation or affecting protein function by MutationTaster and Polyphen2, confirmed the diagnosis. These findings provide important insights into the pathogenesis and inheritance of MM.


Assuntos
Miopatias Distais/genética , Disferlina/genética , Atrofia Muscular/genética , Adulto , Análise Mutacional de DNA , Feminino , Humanos , Mutação de Sentido Incorreto , Adulto Jovem
16.
Phys Chem Chem Phys ; 19(47): 31958-31964, 2017 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-29177324

RESUMO

In this work, we applied an external electric field (F) to a biphenalenyl derivative (BN-PLY2) in the direction of the negative z-axis (F-z) and the positive z-axis (F+z), respectively. The influence of the two directions of F on the molecular structures and electronic properties is investigated, which gives interesting results. Density functional theory (DFT) calculations show that the application of F-z (F-z = 0 to -190 × 10-4) is an advantage toward improving π-dimer stability, which is attributed to an increase in bonding and attractive electrostatic interactions. Interestingly, a large amount of negative charge is induced by applying F-z to the upper layer, resulting in an increase in the electron density in the upper layer, which is the main factor for the formation of a symmetric highest occupied molecular orbital (HOMO) at F-z = -180 × 10-4 au (-9.26 × 109 V m-1). Moreover, when F+z is applied, the HOMO and HOMO-1 undergo orbital interchange in the π-dimer at F+z = 100/110 × 10-4 au. Significantly, the effect of the external electric field effectively regulates the first hyperpolarizabilities (ßtot). When the F+z ranges from 0 to 140 × 10-4 au, the ßtot values slightly decrease to 0 au. Note that, upon increasing F+z, the ßtot values sharply increase to 6.67 × 103 au (F+z = 190 × 10-4 au). Furthermore, the evolutions of the absorption spectra under F might well explain the trend of ßtot values. When the F+z ranges from 0 to 140 × 10-4 au, the broad absorption spikes with a low-energy are significantly blue-shifted, while only absorption spikes with a high-energy are significantly red-shifted (F+z = 140 to 190 × 10-4 au). The present work not only provides a deeper understanding of the relationships between the molecular structure and the electronic properties of a π-dimer system, but can also be developed for designing highly efficient nonlinear optical materials through the influence of an external electric field.

17.
Oncotarget ; 8(44): 77086-77095, 2017 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-29100372

RESUMO

To explore the correlation of aspirin resistance (AR) with clinical stroke severity and infarct volume using diffusion-weighted imaging (DWI) in 224 Chinese ischemic stroke patients who were taking aspirin before stroke onset. In those patients, the median age was 64 years (IQR, 56-75 years), and males accounting for 54.9%(123)of the total subjects. Fifty of 224 enrolled patients (22.3%; 95% confidence interval (CI), 16.9% to 27.7%) showed AR. In the median regression model, significant increase was estimated in NIHSS score of 0.04 point for every 1-point increase in aspirin reaction units (ARU) (95% CI, 0.02 to 0.06; P<0.001). Diffusion-weighted MRI (DWI)-measured infarct volume were significantly higher in patients with AR as compared with those with AS [13.21 (interquartile ranges [IQR], 8.51-23.88) vs.4.26 (IQR, 1.74-11.62); P<0.001). Furthermore, a statistically significant increase was also measured in NIHSS score of 0.05 point for every 1-point increase in ARU in the median regression model (95% CI, 0.03 to 0.08; P<0.001). The median DWI infarct volume was significantly larger in the highest ARU quartile when compared to that in the low 3 quartiles (P<0.001). In conclusion, stroke patients with AR indicated higher risk of severe strokes and large infarcts compared to patients in the aspirin-sensitive group.

18.
Front Neurol ; 8: 531, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29062301

RESUMO

BACKGROUND: To validate our speculation that curcumin may ameliorate Alzheimer's disease (AD) pathogenesis by regulating PI(3,5)P2 and transient receptor potential mucolipin-1 (TRPML1) expression levels. METHODS: We developed an animal model presenting AD by APP/PS1 transgenes. The mouse clonal hippocampal neuronal cell line HT-22 was treated with amyloid-ß1-42 (Aß1-42). Curcumin was administrated both in vivo and in vitro. MTS assay was used to detect cell viability, and the lysosomal [Ca2+] ion concentration was detected. The number of autophagosomes was detected by the transmission electron microscopic examination. Illumina RNA-seq was used to analyze the different expression patterns between Aß1-42-treated cells without and with curcumin treatment. The protein level was analyzed by the Western blotting analysis. PI(3,5)P2 or TRPML1 was knocked down in HT-22 cells or in APP/PS1 transgenic mice. Morris water maze and recognition task were performed to trace the cognitive ability. RESULTS: Curcumin increased cell viability, decreased the number of autophagosomes, and increased lysosomal Ca2+ levels in Aß1-42-treated HT-22 cells. Sequencing analysis identified TRPLML1 as the most significantly upregulated gene after curcumin treatment. Western blotting results also showed that TRPML1 was upregulated and mTOR/S6K signaling pathway was activated and markers of the autophagy-lysosomal system were downregulated after curcumin use in Aß1-42-treated HT-22 cells. Knockdown of PI (3,5)P2 or TRPML1 increased the protein levels of markers of the autophagy-lysosomal system after curcumin use in Aß1-42-treated HT-22 cells, inhibited mTOR/S6K signaling pathway, increased the protein levels of markers of the autophagy-lysosomal system after curcumin use in APP/PS1 mice. Besides, knockdown of PI(3,5)P2 or TRPML1 reversed the protective role of curcumin on memory and recognition impairments in mice with APP/PS1 transgenes. CONCLUSION: To some extent, it suggested that the effects of curcumin on AD pathogenesis were, at least partially, associated with PI(3,5)P2 and TRPML1 expression levels.

19.
Chin Med J (Engl) ; 130(15): 1773-1778, 2017 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-28748848

RESUMO

BACKGROUND: The 9-hole peg test (9-HPT) and 10-meter walk test (10-MWT) are commonly used to test finger motor function and walking ability. The aim of this present study was to investigate the efficacy of these tests for evaluating functional loss in Chinese Charcot-Marie-Tooth (CMT) disease. METHODS: Thirty-four Chinese CMT patients (CMT group) from August 2015 to December 2016 were evaluated with 9-HPT, 10-MWT, CMT disease examination score, overall neuropathy limitation scale (ONLS), functional disability score, and Berg Balance Scale (BBS). Thirty-five age- and gender-matched healthy controls (control group) were also included in the study. Student's nonpaired or paired t-test were performed to compare data between two independent or related groups, respectively. The Pearson test was used to examine the correlations between recorded parameters. RESULTS: The mean 9-HPT completion time in the dominant hand of CMT patients was significantly slower than that in the healthy controls (29.60 ± 11.89 s vs. 19.58 ± 3.45 s; t = -4.728, P < 0.001). Women with CMT completed the 9-HPT significantly faster than men with CMT (dominant hand: 24.74 ± 7.93 s vs. 33.01 ± 13.14 s, t = 2.097, P = 0.044). The gait speed of the average self-selected velocity and the average fast-velocity assessed using 10-MWT for CMT patients were significantly slower than those in the control group (1.03 ± 0.18 m/s vs. 1.44 ± 0.17 m/s, t = 9.333, P < 0.001; 1.31 ± 0.30 m/s vs. 1.91 ± 0.25 m/s, t = 8.853, P < 0.001, respectively). There was no difference in gait speed between men and women. Both 9-HPT and 10-MWT were significantly correlated with the ONLS, functional disability score, and BBS (P < 0.05 for all). CONCLUSION: The 9-HPT and 10-MWT might be useful for functional assessment in Chinese patients with CMT.


Assuntos
Doença de Charcot-Marie-Tooth/diagnóstico , Doença de Charcot-Marie-Tooth/fisiopatologia , Teste de Caminhada/métodos , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Adulto Jovem
20.
J Mol Model ; 23(8): 231, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28726151

RESUMO

A graphene nanoflake (GNF) is a polycyclic aromatic hydrocarbon (PAH) with a huge two-dimensional π-conjugated carbon material in which a central benzene ring is surrounded by identical benzene-type rings through infinite alternant method. In this paper, we explore the structure-aromaticity relationship of the GNFs and the GNFs with hollow sites (GNFHs) by combining the nucleus-independent chemical shifts (NICS) with the anisotropy of the current induced density (ACID). Firstly, the benzene is a typical aromatic molecule (NICS = -9.671 ppm), GNFs 1-6 is darned with benzene and the corresponding GNFHs 1'-6'. Secondly, the NICS values of GNFs 1-6 alternately vary: -1.214 (1) > -13.847 (2) < -2.662 (3) > -14.530 (4) < -3.932 (5) > -13.978 (6) ppm, the GNFs (2, 4, 6) with even fragments of annulene have larger aromaticity than that of GNFs (1, 3, 5) with odd fragments of annulene. Significantly, the NICS values of GNFs 1-6 can also be fragment analyzed by the NICS values and ACID of benzene and corresponding GNFHs 1'-6'. The NICS values for GNFs (2, 4, 6) can be roughly estimated by the NICS value of benzene minus the NICS value of the GNFHs (2', 4', 6'), respectively. The NICS values for GNFs (1, 3, 5) can be roughly estimated by the NICS value of the GNFHs (1', 3', 5') minus the NICS value of benzene, respectively. We hope that the present work can provide a simple and reliable method for the rational design of the GNF with aromaticity, which may be used to understand the origin of the graphene nanoflake aromatic properties.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA