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1.
Hepatobiliary Pancreat Dis Int ; 23(2): 171-180, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37852916

RESUMO

Hepatitis E virus (HEV) is one of the leading causes of acute viral hepatitis worldwide. Although most of HEV infections are asymptomatic, some patients will develop the symptoms, especially pregnant women, the elderly, and patients with preexisting liver diseases, who often experience anorexia, nausea, vomiting, malaise, abdominal pain, and jaundice. HEV infection may become chronic in immunosuppressed individuals. In addition, HEV infection can also cause several extrahepatic manifestations. HEV exists in a wide range of hosts in nature and can be transmitted across species. Hence, animals susceptible to HEV can be used as models. The establishment of animal models is of great significance for studying HEV transmission, clinical symptoms, extrahepatic manifestations, and therapeutic strategies, which will help us understand the pathogenesis, prevention, and treatment of hepatitis E. This review summarized the animal models of HEV, including pigs, monkeys, rabbits, mice, rats, and other animals. For each animal species, we provided a concise summary of the HEV genotypes that they can be infected with, the cross-species transmission pathways, as well as their role in studying extrahepatic manifestations, prevention, and treatment of HEV infection. The advantages and disadvantages of these animal models were also emphasized. This review offers new perspectives to enhance the current understanding of the research landscape surrounding HEV animal models.


Assuntos
Vírus da Hepatite E , Hepatite E , Animais , Humanos , Feminino , Gravidez , Coelhos , Ratos , Camundongos , Suínos , Idoso , Hepatite E/diagnóstico , Vírus da Hepatite E/genética , Modelos Animais
2.
Inorg Chem ; 62(5): 1978-1987, 2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36690448

RESUMO

The low-lying excited-state properties of the water-solvated UO2Cl2 complexes, i.e., (H2O)nUO2Cl2 (n = 1-3), below 33,000 cm-1, are investigated based on the ab initio NEVPT2 and CCSD(T) with inclusion of scalar relativistic and spin-orbit coupling effects. The simulated luminescence spectral curves agree well with the experimental spectrum in aqueous solution at -120 °C. Water coordination is found to significantly affect the character of luminescent state, which is changed from the 3Φg state in UO2Cl2 to the 3Δg state in (H2O)2,3UO2Cl2. This is distinctly different from the observed unchanged nature of luminescent state in the cases of Ar coordination to UO2Cl2 and H2O coordination to UO2F2 in the previous work. Furthermore, by combining with the theoretical results for the solvated UO2F2 system, the reason why water coordination does not remarkably change the spectral shape of UO2Cl2, as opposed to UO2F2, was explained based on the analysis of two key spectral parameters, O-U-O symmetrical vibrational frequency and U-O bond length elongation. The roles of ligand field and spin-orbit coupling in the determination of luminescent state character and spectral shape in uranyl dihalide complexes are deeply discussed and summarized. These results deepen our understanding of the luminescent properties of uranyl complexes in aqueous solution.

3.
Phys Chem Chem Phys ; 25(41): 28452-28464, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37846460

RESUMO

Herein, we have employed a combination of the optimally tuned screened range-separated hybrid (OT-SRSH) functional, the polarizable continuum model (PCM), and nonadiabatic dynamics (NAMD) simulations to investigate the photoinduced dynamics of directly linked donor-acceptor dyads formed using zinc phthalocyanine (ZnPc) and perylenediimide (PDI), in which ZnPc is the donor while PDI is the acceptor. Our simulations aim to analyze the behavior of these dyads upon local excitation of the ZnPc moiety in the gas phase and in benzonitrile. Our findings indicate that the presence of a solvent can significantly influence the excited state dynamics of ZnPc-PDI dyads. Specifically, the polar solvent benzonitrile effectively lowers the vertical excitation energies of the charge transfer (CT) state from ZnPc to PDI. As a result, the energetic order of the locally excited (LE) states of ZnPc and the CT states is reversed compared to the gas phase. Consequently, the photoinduced electron transfer (PET) dynamics from ZnPc to PDI, which is absent in the gas phase, takes place in benzonitrile with a time constant of 10.4 ps. Importantly, our present work not only qualitatively agrees with experimental results but also provides in-depth insights into the underlying mechanisms responsible for the photoinduced dynamics of ZnPc-PDI. Moreover, this study emphasizes the importance of appropriately considering solvent effects in NAMD simulation of organic donor-acceptor systems, taking into account the distinct excited state dynamics observed in the gas phase and benzonitrile. Furthermore, the combination of the OT-SRSH functional, the PCM solvent model, and nonadiabatic dynamics simulations shows promise as a strategy for investigating the complex excited state dynamics of organic donor-acceptor systems in solvents. These findings will be valuable for the future design of novel organic donor-acceptor structures with improved performance.

4.
Hepatobiliary Pancreat Dis Int ; 22(4): 346-351, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37019775

RESUMO

Hepatocellular carcinoma (HCC) is a common malignant tumor. At present, early diagnosis of HCC is difficult and therapeutic methods are limited. Radiomics can achieve accurate quantitative evaluation of the lesions without invasion, and has important value in the diagnosis and treatment of HCC. Radiomics features can predict the development of cancer in patients, serve as the basis for risk stratification of HCC patients, and help clinicians distinguish similar diseases, thus improving the diagnostic accuracy. Furthermore, the prediction of the treatment outcomes helps determine the treatment plan. Radiomics is also helpful in predicting the HCC recurrence, disease-free survival and overall survival. This review summarized the role of radiomics in the diagnosis, treatment and prognosis of HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/terapia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/terapia , Prognóstico , Humanos , Valor Preditivo dos Testes
5.
Sheng Li Xue Bao ; 75(5): 671-681, 2023 Oct 25.
Artigo em Zh | MEDLINE | ID: mdl-37909138

RESUMO

Alzheimer's disease (AD) is a typical cognitive disorder with an increasing incidence in recent years. AD is also one of the main causes of disability and death of the elderly in current aging society. One of the most common symptoms of AD is spatial memory impairment, which occurs in more than 60% of patients. This memory loss is closely related to the impairment of cognitive maps in the brain. The entorhinal grid cells and the hippocampal place cells are important cellular basis for spatial memory and navigation functions in the brain. Understanding the abnormal firing pattern of these neurons and their impaired coordination to neural oscillations in transgenic rodents is crucial for identifying the therapeutic targets for AD. In this article, we review recent studies on neural activity based on transgenic rodent models of AD, with a focus on the changes in the firing characteristics of neurons and the abnormal electroencephalogram (EEG) rhythm in the entorhinal cortex and hippocampus. We also discuss potential cell-network mechanism of spatial memory disorders caused by AD, so as to provide a scientific basis for the diagnosis and treatment of AD in the future.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Animais , Camundongos , Doença de Alzheimer/genética , Animais Geneticamente Modificados , Cognição , Hipocampo/fisiologia , Transtornos da Memória , Camundongos Transgênicos , Neurônios/fisiologia
6.
Chemistry ; 27(12): 4159-4167, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33372312

RESUMO

Whether chemical bonding can regulate the excited-state and optoelectronic properties of donor-acceptor dyads has been largely elusive. In this work, we used electronic structure and nonadiabatic dynamics methods to explore the excited-state properties of covalently bonded zinc phthalocyanine (ZnPc)-fullerene (C60 ) dyads with a 6-6 (or 5-6) bonding configuration in which ZnPc is bonded to two carbon atoms shared by the two hexagonal rings (or a pentagonal and a hexagonal ring) in C60 . In both cases, the locally excited (LE) states on ZnPc are spectroscopically bright. However, their different chemical bonding differentiates the electronic interactions between ZnPc and C60 . In the 5-6 bonding configuration, the LE states on ZnPc are much higher in energy than the LE states on C60 . Thus, the excitation energy transfer from ZnPc to C60 is thermodynamically favorable. On the other hand, in the 6-6 bonding configuration, such a process is inhibited because the LE states on ZnPc are the lowest ones. More detailed mechanisms are elucidated from nonadiabatic dynamics simulations. In the 6-6 bonding configuration, no excitation energy transfer was observed. In contrast, in the 5-6 bonding configuration, several LE and charge-transfer (CT) excitons were shown to participate in the energy-transfer process. Further analysis reveals that the photoinduced energy transfer is mediated by a CT exciton, such that electron- and hole-transfer processes take place in a concerted but asynchronous manner in the excitation energy transfer. It is also found that high-level electronic structure methods including exciton effects are indispensable to accurately describe photoinduced energy- and electron-transfer processes. Furthermore, this work opens up new avenues for regulating the excited-state properties of molecular donor-acceptor dyads by means of chemical bonding.

7.
Phys Chem Chem Phys ; 23(24): 13503-13511, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34120157

RESUMO

Carbon nanomaterials play important roles in modern scientific research. Integrating different carbon-based building blocks into nano-hybrid architectures not only takes full advantage of each component, but also brings in novel interfacial properties. Herein, we have employed density functional theory (DFT) calculations to investigate the effects of polymerization degree of coronene molecules encapsulated in single-walled carbon nanotubes (SWNTs) (19,0) on their interfacial properties. The present results reveal that the interfacial properties of the formed heterojunctions are remarkably regulated by the polymerization degree. For example, monomer- and dimer-encapsulated SWNTs are type-I heterojunctions in which interfacial excitation energy transfer is preferred, whereas interfacial charge carrier transfer is favorable in trimer- and polymer-encapsulated SWNTs because they are type-II heterojunctions. On the other hand, we have employed the time-domain nonadiabatic dynamics simulation approach to explore the interfacial carrier dynamics in type-II polymer-encapsulated SWNT heterojunctions. It is found that the electron and hole transfer processes are asymmetric and occur in opposite directions and at different rates. The former takes place from polymers to SWNTs in an ultrafast way (ca. 370 fs), whereas the latter occurs slowly from SWNTs to polymers (ca. 24 ps). A closer analysis uncovers the fact that the different carrier transfer rates mainly originate from the different densities of the acceptor states, energy differences and inter-state couplings between the donor and acceptor states. Finally, the present work demonstrates that the polymerization degree could act as a new regulating strategy to tune the interfacial properties of molecule-encapsulated SWNT heterojunctions.

8.
Phys Chem Chem Phys ; 23(11): 6536-6543, 2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33690742

RESUMO

Here, we used collinear and noncollinear density functional theory (DFT) methods to explore the interfacial properties of two heterojunctions between a fullerene (C60 and C70) and the MAPbI3(110) surface. Methodologically, consideration of the spin-orbit interaction has been proven to be required to obtain accurate energy-level alignment and interfacial carrier dynamics between fullerenes and perovskites in hybrid perovskite solar cells including heavy atoms (such as Pb atoms). Both heterojunctions are predicted to be the same type-II heterojunction, but the interfacial electron transfer process from MAPbI3 to C60 is completely distinct from that to C70. In the former, the interfacial electron transfer is slow because of the associated large energy gap, and the excited electrons are thus trapped in MAPbI3 for a while. In contrast, in the latter, the smaller energy gap induces ultrafast electron transfer from MAPbI3 to C70. These points are further supported by DFT-based nonadiabatic dynamics simulations including the spin-orbit coupling (SOC) effects. These gained insights could help rationally design superior fullerene-perovskite interfaces to achieve high power conversion efficiencies of fullerene-perovskite solar cells.

9.
J Enzyme Inhib Med Chem ; 36(1): 1715-1731, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34425716

RESUMO

Hippo signalling pathway plays a crucial role in tumorigenesis and cancer progression. In this work, we identified an N-aryl sulphonamide-quinazoline derivative, compound 9i as an anti-gastric cancer agent, which exhibited potent antiproliferative ability with IC50 values of 0.36 µM (MGC-803 cells), 0.70 µM (HCT-116 cells), 1.04 µM (PC-3 cells), and 0.81 µM (MCF-7 cells), respectively and inhibited YAP activity by the activation of p-LATS. Compound 9i was effective in suppressing MGC-803 xenograft tumour growth in nude mice without obvious toxicity and significantly down-regulated the expression of YAP in vivo. Compound 9i arrested cells in the G2/M phase, induced intrinsic apoptosis, and inhibited cell colony formation in MGC-803 and SGC-7901 cells. Therefore, compound 9i is to be reported as an anti-gastric cancer agent via activating the Hippo signalling pathway and might help foster a new strategy for the cancer treatment by activating the Hippo signalling pathway regulatory function to inhibit the activity of YAP.


Assuntos
Antineoplásicos/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Quinazolinas/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Sulfonamidas/farmacologia , Animais , Antineoplásicos/síntese química , Apoptose/efeitos dos fármacos , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Regulação da Expressão Gênica/efeitos dos fármacos , Via de Sinalização Hippo , Humanos , Camundongos Nus , Estrutura Molecular , Quinazolinas/síntese química , Transdução de Sinais , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Sheng Li Xue Bao ; 73(5): 828-834, 2021 Oct 25.
Artigo em Zh | MEDLINE | ID: mdl-34708240

RESUMO

As a kind of mental illness, depression produces great difficulties in clinical diagnosis and treatment, and has a high disability rate. It is urgent to clarify the mechanism of depression to find potential therapeutic targets and effective clinical treatment methods. As a deacetylase, silent mating type information regulator 2 homolog 1 (SIRT1) is involved in many biological processes such as cell aging, cancer, and cardiovascular disease. In recent years, more and more studies have found that SIRT1 gene plays an important role in the pathogenesis of depression, but the mechanism is still unclear. Therefore, this review mainly summarizes the relevant research progress on the role and mechanism of SIRT1 gene in the hippocampus, prefrontal cortex, amygdala, hypothalamic suprachiasmatic nucleus, and nucleus accumbens in depression, in order to provide new ideas for exploring the mechanism and prevention of depression.


Assuntos
Depressão , Sirtuína 1 , Senescência Celular , Depressão/genética , Hipocampo/metabolismo , Humanos , Núcleo Accumbens , Sirtuína 1/genética , Sirtuína 1/metabolismo
11.
Phys Chem Chem Phys ; 22(35): 19542-19548, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32844829

RESUMO

Hybrid carbon materials are found to exhibit novel optoelectronic properties at their interfaces, but the related interfacial carrier dynamics is rarely explored theoretically. In this contribution, we have employed density functional theory (DFT) and DFT-based nonadiabatic dynamics methods to explore photoinduced interfacial electron transfer processes at interfaces between a single-walled carbon nanotube with chiral index (6,5) and C60 or C70 (C60@CNT65 and C70@CNT65). We have found that with low E11 excitation, electron transfer takes place from CNT65 to C60 and C70 in both heterojunctions. This process is ultrafast and completed within about 200 fs, which is consistent with recent experiments. Differently, high E22 excitation does not induce electron injection to C60 in C60@CNT65; instead, "hot" electrons produced within CNT65 will be trapped in its higher conduction band for a while because of slow inter-band relaxation. By contrast, in C70@CNT65, high E22 excitation still can lead to ultrafast electron transfer to C70, but only a comparable amount of electrons are transferred (ca. 30%). Interestingly, electrons either remaining on CNT65 or transferred to C70 are trapped in the higher conduction band for a while, similarly, due to slow inter-band relaxation. The present results could be useful to guide the design of excellent interfaces of mixed-dimensional hybrid carbon materials for various optoelectronic applications.

12.
J Enzyme Inhib Med Chem ; 35(1): 1403-1413, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32588683

RESUMO

Tubulin polymerisation inhibitors that target colchicine binding site were powerful anticancer agents. Although along the years many colchicine binding site inhibitors (CBSIs) have been reported, few piperidine derivatives were identified as CBSIs. In this regard, we focussed efforts on the piperidine as a promising chemotype to develop potent CBSIs. Herein, novel piperidine derivatives were synthesised and evaluated for their antiproliferative activities. Among them, compound 17a displayed powerful anticancer activity with the IC50 value of 0.81 µM against PC3 cells, which was significantly better than 5-fluorouracil. It could inhibit tubulin polymerisation binding at the colchicine site and inhibit the tumour growth in vitro and in vivo. Further biological studies depicted that 17a suppressed the colony formation, induced apoptosis, and inhibited epithelial-mesenchymal transition against PC3 cells. These results revealed that compound 17a is a promising colchicine binding site inhibitor for the treatment of cancer and it is worthy of further exploitation.


Assuntos
Apoptose/efeitos dos fármacos , Colchicina/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Neoplasias da Próstata/patologia , Sítios de Ligação , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Masculino , Espectrometria de Massas , Piperidinas/farmacologia , Espectroscopia de Prótons por Ressonância Magnética
13.
J Enzyme Inhib Med Chem ; 35(1): 1050-1059, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32299262

RESUMO

Tubulin polymerisation inhibitors exhibited an important role in the treatment of patients with prostate cancer. Herein, we reported the medicinal chemistry efforts leading to a new series of benzothiazoles by a bioisosterism approach. Biological testing revealed that compound 12a could significantly inhibit in vitro tubulin polymerisation of a concentration dependent manner, with an IC50 value of 2.87 µM. Immunofluorescence and EBI competition assay investigated that compound 12a effectively inhibited tubulin polymerisation and directly bound to the colchicine-binding site of ß-tubulin in PC3 cells. Docking analysis showed that 12a formed hydrogen bonds with residues Tyr357, Ala247 and Val353 of tubulin. Importantly, it displayed the promising antiproliferative ability against C42B, LNCAP, 22RV1 and PC3 cells with IC50 values of 2.81 µM, 4.31 µM, 2.13 µM and 2.04 µM, respectively. In summary, compound 12a was a novel colchicine site tubulin polymerisation inhibitor with potential to treat prostate cancer.


Assuntos
Antineoplásicos/farmacologia , Benzotiazóis/farmacologia , Colchicina/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Benzotiazóis/síntese química , Benzotiazóis/química , Proliferação de Células/efeitos dos fármacos , Colchicina/síntese química , Colchicina/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular , Células PC-3 , Relação Estrutura-Atividade , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/química , Células Tumorais Cultivadas
14.
Sheng Li Xue Bao ; 72(6): 793-803, 2020 Dec 25.
Artigo em Zh | MEDLINE | ID: mdl-33349838

RESUMO

The formation, consolidation and retrieval of spatial memory depend on sequential firing patterns of place cells assembling in the hippocampus. Theta sequences of place cells during behavior play a role in acquisition of spatial memory, trajectory prediction and decision making. In awake rest and slow wave sleep, place cell sequences occur during the sharp wave-ripples (SWRs), called "replay", which is crucial for memory consolidation and retrieval. In this review, we summarize the functional significances of theta sequences and SWRs replay sequences and the mechanism of these sequences. We also discuss the relationship between theta and replay sequences with the formation of spatial memory. We propose the research direction in this field in future and aim to provide new ideas for related researches.


Assuntos
Hipocampo , Memória Espacial , Sono , Vigília
15.
J Phys Chem A ; 123(46): 10019-10029, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31661964

RESUMO

Two-dimensional (2D) heterostructures of black phosphorus (BP)/bismuth vanadate (BVO) have attracted much attention due to their potential uses in photocatalytic water splitting. However, the interfacial photoinduced electron- and hole-transfer dynamics are not explored computationally. Herein, we have used density functional theory (DFT) calculations and DFT-based fewest-switches surface-hopping dynamics simulations to investigate the light-driven electron and hole dynamics taking place at the interface of BP and the BVO(010) surface. Our results show that the BP monolayer is adsorbed on BVO(010) via van der Waals interaction. Upon irradiation, the electron transfer takes place from BP to BVO(010) within 500 fs but with two distinct processes. In the first phase, the electron transfer proceeds adiabatically and is mainly driven by atomic motions. In the second phase, the electron transfer decays very slowly. The hole-transfer dynamics from BVO(010) to BP exhibits a similar ultrafast decay in the first stage followed by a slow decay; however, there is a comparable amount of hole trapped in a BP state due to a large energy gap from its higher state. These insights may be useful for the design of novel photocatalytic water-splitting materials.

16.
Bioorg Chem ; 86: 375-385, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30763884

RESUMO

Novel chalcone-dithiocarbamate hybrids were designed, synthesized and evaluated for antiproliferative activity against selected cancer cell lines (MGC803, MCF7, and PC3). Among these analogues, (E)-2-oxo-2-((4-(3-(3,4,5-trimethoxyphenyl)acryloyl)phenyl)amino)ethyl-4-(2-hydroxyethyl)piperazine-1-carbodithioate (12d) showed the best inhibitory activity against PC3 cells (IC50 = 1.05 µM). Cellular mechanism studies elucidated 12d could inhibit colony formation, arrest cell cycle at G2/M phase and induce DNA damage against PC3 cells. Compound 12d also induced mitochondrial apoptosis by caspase activation, MMP decrease, ROS production and catalase (CAT) inhibition. Importantly, 12d inhibited epithelial-mesenchymal transition (EMT) process by regulating EMT-related proteins (E-cadherin, N-cadherin, Vimentin, MMP2, MMP9). These results indicated that 12d is a promising lead compound and deserves further investigation for prevention and treatment of human prostate cancer.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Catalase/antagonistas & inibidores , Chalcona/farmacologia , Inibidores Enzimáticos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Tiocarbamatos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Catalase/metabolismo , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Chalcona/síntese química , Chalcona/química , Relação Dose-Resposta a Droga , Descoberta de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Células MCF-7 , Simulação de Acoplamento Molecular , Estrutura Molecular , Células PC-3 , Espécies Reativas de Oxigênio/análise , Relação Estrutura-Atividade , Tiocarbamatos/síntese química , Tiocarbamatos/química , Células Tumorais Cultivadas
17.
Phys Chem Chem Phys ; 20(23): 16138-16150, 2018 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-29854994

RESUMO

Herein, we employed combined CASPT2 and B3LYP electronic structure methods in the framework of the quantum mechanics/molecular mechanics (QM/MM) approach to explore the ozonolysis of α-humulene and subsequent Criegee reactions with acids and water at the air-water/acetonitrile interface as a surrogate for atmospheric aqueous organic media. First, we found that the 1,3-cycloaddition reactions of ozone on α-humulene proceed concertedly and have small barriers (less than 2.5 kcal mol-1) at the QM(CASPT2)/MM level. Second, the five-membered ring cleavage reactions of the generated ozonides are rate-limiting steps and have considerable barriers (more than 10.0 kcal mol-1). These ring-opening reactions are also concerted and simultaneously lead to the cleavage of O-O and C-C bonds, producing sesquiterpene Criegee intermediates at the air-water/acetonitrile interface. Third, although these Criegee intermediates can react with water and acids near the air-water/acetonitrile boundary, the addition reactions with acids have smaller barriers, which range from 2.7 kcal mol-1 of R1-COOH to 5.6 kcal mol-1 of R7-COOH. In contrast, in water addition reactions, several different water-mediated reaction pathways have been disclosed. Their reaction barriers are found to decrease remarkably with an increase in the number of water molecules involved in the reactions. Finally, we found that in addition to low water concentration near the air-water/acetonitrile boundary, distinct reactivities of Criegee intermediates with acids and water play very important roles in the determination of the fates of the Criegee intermediates. Our present QM/MM study provides new mechanistic insights into ozonolysis and Criegee reactions at air-water/acetonitrile interfaces and gives important implications for new particle formation and secondary organic aerosol formation near the marine boundary.

18.
Anal Biochem ; 539: 127-133, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29107578

RESUMO

MicroRNAs (miRNAs) play an important role in many biological processes, and its level in plasma and other biological fluids is closely related to many diseases. In this work, a selective room-temperature phosphorescence (RTP) detection method for miRNA was developed based on a duplex-specific nuclease (DSN) -assisted signal amplification strategy and phosphorescence resonance energy transfer (PRET) between poly-diallyldimethylammonium chloride-modified quantum dots (QDs@PDDA) and 6-carboxy-X-rhodamine-modified miRNA sequences complementary oligonucleotide (ROX-ssDNA). The positively charged QDs@PDDA could adsorb negatively charged ROX-ssDNA by electrostatic interaction, whereas the RTP signal of QDs@PDDA could be efficiently quenched by ROX-ssDNA via PRET. In the presence of microRNA-21 (miR-21) and DSN, miR-21 hybridized with ROX-ssDNA initially to form a DNA-RNA heteroduplex as the substrate of DSN, then ssDNA in DNA-RNA heteroduplex would be cleaved into small fragments by DSN and liberate miR-21 to hybridize with another ROX-ssDNA. Eventually, due to weak interaction between ROX-ssDNA fragments and QDs@PDDA, PRET efficiency continually decreased whereas the RTP signal was significantly amplified. By employing the strategy above, quantitative detection of miR-21 in the range of 0.25-40 nM with a detection limit of 0.16 nM was realized, showing excellent performance with simplicity, good selectivity and the ability to be a promising method for miRNA detection.


Assuntos
Endonucleases/metabolismo , Transferência Ressonante de Energia de Fluorescência , MicroRNAs/análise , DNA de Cadeia Simples/química , DNA de Cadeia Simples/metabolismo , MicroRNAs/química , MicroRNAs/metabolismo , Hibridização de Ácido Nucleico , Polietilenos/química , Pontos Quânticos/química , Compostos de Amônio Quaternário/química , Rodaminas/química , Eletricidade Estática
19.
Mol Divers ; 21(4): 933-942, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28785928

RESUMO

Novel phenothiazine-dithiocarbamate analogues were designed by molecular hybridization strategy and synthesized and evaluated for their anticancer activity in vitro against three selected cancer cell lines (EC-109, MGC-803, and PC-3). The preliminary structure-activity relationship (SAR) for this phenothiazine-dithiocarbamate hybrids is explored. Among all analogues, 2-oxo-2-(10H-phenothiazin-10-yl)ethyl 4-ethylpiperazine-1-carbodithioate (8a) showed the most potent inhibitory activity with an [Formula: see text] value of [Formula: see text] against PC-3 cells. In addition, compound 8a could arrest the cell cycle at the G1 phase and regulate the expression of G1 checkpoint-related proteins, suggesting that phenothiazine-dithiocarbamate hybrids might be useful as cell cycle blockers.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Desenho de Fármacos , Fenotiazinas/síntese química , Fenotiazinas/farmacologia , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Técnicas de Química Sintética , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Fenotiazinas/química , Relação Estrutura-Atividade
20.
Sheng Li Xue Bao ; 69(6): 805-816, 2017 Dec 25.
Artigo em Zh | MEDLINE | ID: mdl-29270597

RESUMO

Neural oscillations cross-frequency coupling (CFC) refers to the effect of the cross modulation between the electrophysiological oscillation rhythm in different ensembles of neurons. The CFC can reflect the mechanism of information transfer and exchange of local field potentials, electroencephalograph (EEG) and other neural electrophysiological activities at different spatial and temporal scales and plays an important role in the study of cognitive function. This paper introduces the basic phenomenon and classifications of neural oscillation CFC briefly, and reviews the typical applications in the study of the animal cognition model and human cognitive function in recent years, respectively. The main problems are also summarized and the future research is prospected in order to provide new ideas to promote the study and application of the CFC.


Assuntos
Cognição/fisiologia , Neurônios/fisiologia , Animais , Eletroencefalografia , Humanos
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