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1.
BMC Public Health ; 23(1): 356, 2023 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-36800949

RESUMO

BACKGROUND: China has one of the fastest paces of the growing aging population, High-level policymakers have recently recognized the aging population presents significant challenges to the Chinese healthcare system. In this context, the healthcare-seeking behaviors of the elderly population have become an essential field of study. It is necessary to understand their access to health services and to improve their quality of life, as well as to help policymakers to formulate healthcare policy. The study empirically investigates the factors influencing the elderly population's healthcare-seeking behaviors in Shanghai, China, especially in choosing the quality of healthcare facilities to visit. METHODS: We designed a cross-sectional study. The data of this study were derived from the "Shanghai elderly medical demand characteristics questionnaire" in the middle of November to early December 2017. A total of 625 individuals were included in the final sample. Logistic regression was adopted to investigate the differences in healthcare-seeking behaviors between elderly people when suffer from mild illness, severe illness and follow-up treatment. Next, the differences in gender were also discussed. RESULTS: Factors affecting the healthcare-seeking behaviors of the elderly differ in mild illness and severe illness situations. For mild illness, demographic factors (gender and age) and socioeconomic factors (income and employment) play an important role in elderly healthcare choices. Female and older elderlies are more likely to choose local, lower-quality facilities, whereas those with high income and private employment are more likely to choose higher-quality facilities. For severe illness, socioeconomic factors (income and employment) are important. Furthermore, individuals with basic medical insurance are more likely to choose lower-quality facilities. CONCLUSION: This study has shown that the affordability of public health services should be addressed. Medical policy support may be an important way to reduce the gap in access to medical services. We should pay attention to the gender differences in the elderly's choice of medical treatment behavior, consider the differences in the needs of male and female elderly. our findings are only for elderly Chinese participants in the greater Shanghai area.


Assuntos
Instalações de Saúde , Qualidade de Vida , Humanos , Masculino , Feminino , Idoso , Estudos Transversais , China , Atenção à Saúde
2.
Environ Toxicol ; 36(2): 249-256, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32946155

RESUMO

Cardiovascular-related diseases continue to be a leading cause of death globally. Among ischemic-induced cardiac diseases, myocardial infarction (MI) is reported to be of an alarming value. Despite numerous improvements in the medical intrusions, still this armamentarium fails to be effective in managing the illness without setbacks. Ferruginol (FGL) is a major polyphenols and terpenoids with numerous pharmacological activities including antioxidant and anti-inflammatory. Following, this work was aimed to explore the cardio protective effect of FGL (50 mg/kg) in isoprenaline hydrochloride (ISO)-induced MI in experimental rats. After treatment with FGL in ISO-induced MI in rats, noticeable changes were observed in the experimental rats. Injection of ISO to rats resulted in the augmented cardiac weight, serum cardiac markers (creatine kinase, creatine kinase-MB, cardiac troponin T, and Cardiac troponin I), lipid peroxidation end products (thiobarbituric acid-reactive substance and lipid hydroperoxides), reduced endogenous antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione), reduced ATPase activity, and escalated pro-inflammatory cytokines (interleukin-6, tumor necrosis factor-α, and nuclear factor-κB) levels. Interestingly, the FGL supplementation to the ISO-treated rats revealed the diminished heart weight, reduced cardiac markers, and lipid peroxidation. FGL also possessed the improved antioxidants status and diminished pro-inflammatory mediator levels. The outcomes of histological analysis also evidenced the cardio protective role of FGL. Treatment with FGL reduced the cardiac damage biomarkers maintained to near normal levels in ISO-induced rats. These study findings disclose the prospective capability of FGL in the treatment of MI in the future.


Assuntos
Abietanos/farmacologia , Antioxidantes/farmacologia , Infarto do Miocárdio/tratamento farmacológico , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Catalase/metabolismo , Modelos Animais de Doenças , Glutationa Peroxidase/metabolismo , Coração/efeitos dos fármacos , Isoproterenol/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Peróxidos Lipídicos/metabolismo , Masculino , Infarto do Miocárdio/induzido quimicamente , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Ratos , Ratos Wistar , Superóxido Dismutase/metabolismo , Troponina T/metabolismo
3.
J Neurosci Res ; 98(2): 353-370, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31359506

RESUMO

The relationships of digit ratio (2D:4D) with the length of AR (CAG)n, and testosterone levels from saliva and blood have been extensively debated over the years. This research including three studies further clarifies such controversies. To do so, we re-examined the relationships between the length of AR (CAG)n, 2D:4D, and current testosterone levels, through replication study and meta-analysis for each study. The results indicate: (a) the length of AR (CAG)n is not significantly associated with 2D:4D; (b) current testosterone levels are not significantly associated with the ratio; and (c) the length is not significantly associated with testosterone levels. Thus, AR (CAG)n and current testosterone levels are not significantly related to 2D:4D at individual level.


Assuntos
Dedos/anatomia & histologia , Polimorfismo Genético , Receptores Androgênicos/genética , Testosterona/análise , Feminino , Genótipo , Humanos , Masculino , Saliva/química , Adulto Jovem
4.
Plant Cell Rep ; 39(2): 217-226, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31728702

RESUMO

KEY MESSAGE: RsMYB1a was the crucial MYB, and RsbHLH4 is the essential partner in regulating the anthocyanin biosynthesis in radish. There are four color types of radish according to whether or not the anthocyanin accumulates in the skin and flesh of taproot. Red radishes accumulate a substantial amount of anthocyanins in both the skin and flesh. It is well known that the MYB-bHLH-WD40 transcription factor(s) complex regulates the biosynthesis of anthocyanin in plants. Here in, four candidate MYB and bHLH genes, RsMYB1a, RsMYB1b, RsbHLH2 and RsbHLH4, were isolated from red radish 'Hongxin 1'. The expression of RsbHLH4 and the two structural genes RsANS and RsUFGT was significantly positively correlated with anthocyanin contents. The expression of RsMYB1a was also highly correlated with anthocyanin accumulation, particularly when the white flesh sample of 'Hongxin 1-1' was excluded. The transient expression of RsMYB1a in the radish cotyledon and leaf induced anthocyanin accumulation with even stronger promoting role when expression in combination with RsbHLH4. These results suggested that RsMYB1a was the crucial MYB, and that RsbHLH4 is an essential partner in regulating the biosynthesis of anthocyanins in radish. The low or undetectable RsbHLH4 expression paralleled the lack of anthocyanin accumulation in the white flesh of 'Hongxin 1-1' and 'Shaguan 1'. Assays demonstrated that RsMYB1a interacted with RsbHLH4 and activated the expression of RsbHLH4. Notably, all the dark red radish cultivars have a longer RsMYB1a genomic DNA sequence, while the short and nonfunctional RsMYB1a is present in non-red cultivars. The length of the first intron and the presence of an early stop codon of RsMYB1 might underlie the differential anthocyanin accumulation in the radish taproot.


Assuntos
Antocianinas/metabolismo , DNA de Plantas/isolamento & purificação , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raphanus/genética , Clonagem Molecular , DNA de Plantas/genética , Perfilação da Expressão Gênica , Folhas de Planta/química , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/química , Raphanus/química
5.
Chemistry ; 25(28): 6853-6863, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-30698852

RESUMO

Cytochrome P450 enzymes (P450s) catalyze the monooxygenation of various organic substrates. These enzymes are fascinating and promising biocatalysts for synthetic applications. Despite the impressive abilities of P450s in the oxidation of C-H bonds, their practical applications are restricted by intrinsic drawbacks, such as poor stability, low turnover rates, the need for expensive cofactors (e.g., NAD(P)H), and the narrow scope of useful non-native substrates. These issues may be overcome through the general strategy of protein engineering, which focuses on the improvement of the catalysts themselves. Alternatively, several emerging strategies have been developed that regulate the P450 catalytic process from the viewpoint of the substrate. These strategies include substrate engineering, decoy molecule, and dual-functional small-molecule co-catalysis. Substrate engineering focuses on improving the substrate acceptance and reaction selectivity by means of an anchoring group. The latter two strategies utilize co-substrate-like small molecules that either are proposed to reform the active site, thereby switching the substrate specificity, or directly participate in the catalytic process, thereby creating new catalytic peroxygenation capabilities towards non-native substrates. For at least 10 years, these approaches have played unique roles in solving the problems highlighted above, either alone or in conjunction with protein engineering. Herein, we review three strategies for substrate regulation in the P450-catalyzed oxidation of non-native substrates. Furthermore, we address remaining challenges and potential solutions associated with these approaches.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Engenharia de Proteínas , Animais , Bactérias/química , Bactérias/enzimologia , Bactérias/genética , Bactérias/metabolismo , Biocatálise , Domínio Catalítico , Sistema Enzimático do Citocromo P-450/química , Humanos , Simulação de Acoplamento Molecular , Oxirredução , Engenharia de Proteínas/métodos , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/metabolismo , Especificidade por Substrato
6.
Int J Mol Sci ; 20(17)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480213

RESUMO

Cafestol and kahweol are natural diterpenes extracted from coffee beans. In addition to the effect of raising serum lipid, in vitro and in vivo experimental results have revealed that the two diterpenes demonstrate multiple potential pharmacological actions such as anti-inflammation, hepatoprotective, anti-cancer, anti-diabetic, and anti-osteoclastogenesis activities. The most relevant mechanisms involved are down-regulating inflammation mediators, increasing glutathione (GSH), inducing apoptosis of tumor cells and anti-angiogenesis. Cafestol and kahweol show similar biological activities but not exactly the same, which might due to the presence of one conjugated double bond on the furan ring of the latter. This review aims to summarize the pharmacological properties and the underlying mechanisms of cafestol-type diterpenoids, which show their potential as functional food and multi-target alternative medicine.


Assuntos
Diterpenos/farmacologia , Inibidores da Angiogênese/farmacologia , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Diterpenos/química , Humanos , Hipoglicemiantes/farmacologia
8.
Arch Virol ; 162(9): 2913-2917, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28577215

RESUMO

We have recently reported the identification of 10 double-strand RNA segments from Sclerotium hydrophilum [HZ11] mycelia and of virus-like particles isolated from the mycelia, as well as the sequences of dsRNA2 and dsRNA7. Phylogenetic analysis revealed that dsRNA2 and dsRNA7 belong to a group of unclassified viruses. In this report, we cloned and sequenced dsRNA6 and dsRNA9 from the 10 dsRNAs. We tentatively named the putative virus "Sclerotium hydrophilum virus 1", with isolates being abbreviated to ShV1, with dsRNA6 and dsRNA9 corresponding to dsRNA1 and dsRNA2, respectively, of ShV1. dsRNA1 was 1975 bp in length and encoded a putative RNA-dependent RNA polymerase (RdRp). dsRNA2 was 1728 bp and encoded a putative coat protein (CP). Phylogenetic analysis showed that the proteins encoded by dsRNA1 and dsRNA2 were highly related to known viral RdRps and CP, respectively, of viruses classified within the genus Alphapartitivirus of the family Partitiviridae. These members include Rhizoctonia solani dsRNA virus 2, Diuris pendunculata cryptic virus, and Heterobasidion partitivirus. The 5'- and 3'-untranslated regions (UTRs) of the two dsRNAs showed a high sequence identity. The 5'-UTR contained conserved sequences 5'-GAAGCAUCACUU(/G) G(/U)AGU(/A)UCGC(/U)CCA(/G) CAAUAACGAA-3' and 5'-AAAUUGAUCUUACCUCUCAC-3'. The 3'-UTR contained the conserved sequence 5'-UUGUUUU-3' and 5'-UUUA(/U)A(/C) UUAU-3'. These results indicate that dsRNA1 and dsRNA2 are phylogenetically related to members of the genus Alphapartitivirus of family Partitiviridae. We therefore propose that dsRNA1 and dsRNA2 are the genome sequences of a new partitivirus, ShV1.


Assuntos
Basidiomycota/virologia , Micovírus/genética , RNA de Cadeia Dupla/genética , RNA Viral/genética , Filogenia
9.
Bioorg Med Chem Lett ; 26(9): 2355-9, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26995527

RESUMO

A series of novel ATB-429 (an anti-inflammatory candidate) derivatives containing a nitric oxide (NO)-releasing moiety were designed, synthesized and evaluated for their in vitro activity against six human cancer cell lines. Our results reveal that phenylsulfonylfuroxan-based derivatives have considerable antitumor activity, and compounds 7-9 (IC50s: 0.256-3.024 µM) against HT-29 and PANC-1, 8a,b (IC50s: 2.677-3.051 µM) against MCF-7 and 8a (IC50: 1.270 µM) against DU145 are more active than Vandetanib (IC50s: 1.925-4.107 µM).


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Dissulfetos/química , Mesalamina/química , Óxido Nítrico/química , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Humanos
10.
Virus Genes ; 52(6): 823-827, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27473231

RESUMO

Ten dsRNA segments were extracted from Sclerotium hydrophilum isolate (HZ11). The isolation of virus-like particles contained 10 dsRNA segments with the same number and migration as those extracted directly from the fungal mycelia. Two of these dsRNA segments, dsRNA2 and dsRNA7, were cloned and sequenced. They were 2121 and 1953 bp, respectively. The dsRNA2 encodes a RNA-dependent RNA polymerase. The dsRNA7 contains two open reading frames that encode putative proteins of unknown functions. Phylogenetic analysis of the putative proteins indicated that they are closely related to protein encoded by unclassified viruses, such as Cryphonectria parasitica bipartite mycovirus 1, Lactarius rufus RNA virus 1, Penicillium aurantiogriseum bipartite virus 1, and Curvularia thermal tolerance virus. The 5'- and 3'-untranslated regions of the two dsRNAs share significant sequence identity and contain conserved sequence stretches. It suggested that dsRNA2 and dsRNA7 have a common origin and a close phylogenetic relationship to a group of unclassified viruses.


Assuntos
Basidiomycota/classificação , Basidiomycota/genética , Filogenia , RNA de Cadeia Dupla/genética , RNA Fúngico/genética , Vírus não Classificados/genética , Sequência de Bases , Oryza/microbiologia , RNA de Cadeia Dupla/química , RNA Fúngico/química , Análise de Sequência de DNA , Vírus não Classificados/classificação
11.
Small ; 11(2): 208-13, 2015 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-25115804

RESUMO

Charge trapping layers are formed from different metallic nanocrystals in MoS2 -based nanocrystal floating gate memory cells in a process compatible with existing fabrication technologies. The memory cells with Au nanocrystals exhibit impressive performance with a large memory window of 10 V, a high program/erase ratio of approximately 10(5) and a long retention time of 10 years.

12.
Bioorg Med Chem Lett ; 25(22): 5058-63, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26476970

RESUMO

A series of novel 1-[(1R,2S)-2-fluorocyclopropyl]naphthyridone derivatives 21-24 containing an oxime-functionalized pyrrolidine moiety were designed, synthesized and evaluated for their biological activity. Our results reveal that compounds 21a, 21e and 21j show considerable activity against MTB H37Rv ATCC 27294 (MICs: <0.25 µg/mL) and MDR-MTB 6133 (MICs: 0.03-0.054 µg/mL). The target compounds 21-24 are generally poor against the Gram-negative strains, but 21a-j and 22a-c have potent potency (MICs: <0.008-32 µg/mL) against all of the tested Gram-positive strains including MRSA and MRSE with a few exceptions, and the most active compounds 21d, 21e and 22a-c (MICs: <0.008-32 µg/mL) were found to be comparable to or better than moxifloxacin, and 2->250 times more potent than ciprofloxacin and levofloxacin.


Assuntos
Antibacterianos/farmacologia , Naftiridinas/farmacologia , Oximas/farmacologia , Pirrolidinas/farmacologia , Antibacterianos/síntese química , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana Múltipla , Fluoroquinolonas/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Levofloxacino/farmacologia , Moxifloxacina , Naftiridinas/síntese química , Oximas/síntese química , Pirrolidinas/síntese química , Estereoisomerismo
13.
Bioorg Med Chem Lett ; 25(14): 2782-7, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26009164

RESUMO

We report herein the design and synthesis of a series of novel 5-halogenated-7-azaindolin-2-one derivatives containing a 2,4-dimethylpyrrole moiety. Nine target compounds with ⩾70% inhibition against MCF-7 at 30 µM were further evaluated for their in vitro antitumor activity against seven human cancer cell lines by SRB assay. Results reveal that some compounds have potent antitumor activity, and the most active 13c7 (IC50s: 4.49-15.39 µM) was found to be more active than Sunitinib (IC50s: 4.70->30 µM) against all of the tested cancer cell lines.


Assuntos
Amidas/química , Amidas/farmacologia , Amidas/síntese química , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis , Células MCF-7 , Pirimidinas/química , Pirróis/química , Relação Estrutura-Atividade , Sunitinibe
14.
Mol Cell Biochem ; 385(1-2): 265-75, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24104452

RESUMO

Glioblastoma is the most aggressive cerebral gliomas. Despite advances in therapies, the prognosis is still very poor. Therefore, novel therapeutic strategies are required. As a proteasome inhibitor, bortezomib has shown its efficacy as an active antitumor agent against a variety of tumors. However, inhibition of proteasome activity leads to cell death and also induces cell autophagy, and due to the dual roles of autophagy in the survival and death of tumor cells, the effect of inhibition of autophagy on glioblastoma cells remains to be explored. We therefore assessed whether bortezomib is capable of inducing autophagy, and investigated the antitumor effect of bortezomib combined with autophagy inhibitors on human glioblastoma U251 and U87 cells. Cell viability was measured by MTT assay. The expressions of autophagy and apoptosis-related proteins were determined by Western blot analysis. U251 and U87 cells proliferation was inhibited in a dose-dependent manner. Both apoptosis and autophagy induced by bortezomib were observed in human glioblastoma U87 and U251 cells. However, when U251 and U87 cells were co-treated with bortezomib and autophagy inhibitors 3-MA or Atg7 siRNA, the autophagy inhibitors blocked the autophagy in the cells and resulted in a further inhibition of cell proliferation and a further increase in cell apoptosis as compared with that treated with bortezomib alone. These findings indicated that combination of bortezomib and autophagy inhibitors may shed new light on glioblastoma treatment.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Ácidos Borônicos/farmacologia , Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Inibidores de Proteassoma/farmacologia , Pirazinas/farmacologia , Adenina/análogos & derivados , Adenina/farmacologia , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 7 Relacionada à Autofagia , Bortezomib , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Glioblastoma/metabolismo , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , RNA Interferente Pequeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Enzimas Ativadoras de Ubiquitina/metabolismo
15.
J Asian Nat Prod Res ; 16(11): 1035-43, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25355458

RESUMO

Eight bibenzyl derivatives, namely dendrocandins J-Q (1-8), were isolated from the stems of Dendrobium candidum. Their structures were elucidated by 1D and 2D NMR experiments and mass spectrometry. Compounds 1-8 were examined for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay, and the IC50 values were 36.8, 70.2, 45.0, 60.5, 87.6, 50.4, 22.3, and 30.3 µM, respectively.


Assuntos
Antioxidantes/isolamento & purificação , Bibenzilas/isolamento & purificação , Dendrobium/química , Medicamentos de Ervas Chinesas/isolamento & purificação , Sequestradores de Radicais Livres/isolamento & purificação , Antioxidantes/química , Antioxidantes/farmacologia , Bibenzilas/química , Compostos de Bifenilo/farmacologia , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacologia , Concentração Inibidora 50 , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Picratos/farmacologia , Caules de Planta/química
16.
Nano Lett ; 13(7): 3287-92, 2013 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-23796312

RESUMO

"One key to one lock" hybrid sensor configuration is rationally designed and demonstrated as a direct effective route for the target-gas-specific, highly sensitive, and promptly responsive chemical gas sensing for room temperature operation in a complex ambient background. The design concept is based on three criteria: (i) quasi-one-dimensional metal oxide nanostructures as the sensing platform which exhibits good electron mobility and chemical and thermal stability; (ii) deep enhancement-mode field-effect transistors (E-mode FETs) with appropriate threshold voltages to suppress the nonspecific sensitivity to all gases (decouple the selectivity and sensitivity away from nanowires); (iii) metal nanoparticle decoration onto the nanostructure surface to introduce the gas specific selectivity and sensitivity to the sensing platform. In this work, using Mg-doped In2O3 nanowire E-mode FET sensor arrays decorated with various discrete metal nanoparticles (i.e., Au, Ag, and Pt) as illustrative prototypes here further confirms the feasibility of this design. Particularly, the Au decorated sensor arrays exhibit more than 3 orders of magnitude response to the exposure of 100 ppm CO among a mixture of gases at room temperature. The corresponding response time and detection limit are as low as ∼4 s and ∼500 ppb, respectively. All of these could have important implications for this "one key to one lock" hybrid sensor configuration which potentially open up a rational avenue to the design of advanced-generation chemical sensors with unprecedented selectivity and sensitivity.


Assuntos
Técnicas Biossensoriais/instrumentação , Condutometria/instrumentação , Gases/análise , Nanopartículas Metálicas/química , Nanotecnologia/instrumentação , Nanofios/química , Transistores Eletrônicos , Desenho de Equipamento , Análise de Falha de Equipamento , Gases/química , Nanopartículas Metálicas/ultraestrutura , Microquímica/instrumentação , Nanofios/ultraestrutura
17.
Inorg Chem ; 52(16): 9557-66, 2013 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-23909819

RESUMO

This paper reports preparation, characterization, and reactivity of iodosylarene adducts of a manganese(IV) salen complex. In order to systematically investigate steric and electronic factors that control reactivity and selectivity, we prepared iodosylarene adducts from iodosylbenzene, iodosylmesitylene, 2,4,6-triethyliodosylbenzene, and pentafluoroiodosylbenzene. We also investigated the effect of anions on I(III) by using chloride, benzoate, and p-toluenesulfonate. Spectroscopic studies using (1)H NMR, electron paramagnetic resonance, infrared spectroscopy, and electrospray ionization mass spectrometry show that these iodosylarene adducts are manganese(IV) complexes bearing two iodosylarenes as external axial ligands. Reactions with thioanisole under the pseudo-first-order conditions show that the electron-withdrawing pentafluorophenyl group and the p-toluenesulfonate anion on I(III) significantly accelerate the oxygen-atom transfer. The high reactivity is correlated with a weakened I-OMn bond, as indicated by IR spectroscopy and mass spectrometry. Stoichiometric reactions with styrenes show that both enantioselectivity and diastereoselectivity are dependent on the arenes and anions on I(III) of the coordinate iodosylarenes. Notably, the pentafluorophenyl group and the p-toluenesulfonate anion suppress the cis-to-trans isomerization in the epoxidation of cis-ß-methylstyrene. The present results show that iodosylarene adducts of manganese(IV) salen complexes are indeed active oxygen-atom-transfer reagents and that their reactivity and selectivity are regulated by steric and electronic properties of the arenes and anions on I(III) of the coordinated iodosylarenes.


Assuntos
Complexos de Coordenação/química , Etilenodiaminas/química , Iodo/química , Iodobenzenos/química , Manganês/química , Oxigênio/química , Ânions/química , Complexos de Coordenação/síntese química , Modelos Moleculares , Estrutura Molecular
18.
Magn Reson Chem ; 51(6): 371-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23616348

RESUMO

Five new glucosides, shancigusins E-I (1-5) were isolated from the tubers of Pleione yunnanensis (Rolfe) together with 18 known compounds. The structures of these compounds were determined by extensive analyses of their spectroscopic data.


Assuntos
Glucosídeos/química , Orchidaceae/química , Espectroscopia de Ressonância Magnética/normas , Estrutura Molecular , Padrões de Referência
19.
Nano Lett ; 12(7): 3596-601, 2012 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-22694726

RESUMO

Here we report unique performance transistors based on sol-gel processed indium zinc oxide/single-walled carbon nanotube (SWNT) composite thin films. In the composite, SWNTs provide fast tracks for carrier transport to significantly improve the apparent field effect mobility. Specifically, the composite thin film transistors with SWNT weight concentrations in the range of 0-2 wt % have been investigated with the field effect mobility reaching as high as 140 cm(2)/V·s at 1 wt % SWNTs while maintaining a high on/off ratio ∼10(7). Furthermore, the introduction SWNTs into the composite thin film render excellent mechanical flexibility for flexible electronics. The dynamic loading test presents evidently superior mechanical stability with only 17% variation at a bending radius as small as 700 µm, and the repeated bending test shows only 8% normalized resistance variation after 300 cycles of folding and unfolding, demonstrating enormous improvement over the basic amorphous indium zinc oxide thin film. The results provide an important advance toward high-performance flexible electronics applications.

20.
Int J Mol Sci ; 14(11): 22967-81, 2013 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-24264041

RESUMO

The effect of temperature shift on Polyporus umbellatus sclerotial development was investigated. Micromorphology of the sclerotia was observed by using scanning electron microscopy (SEM). The cytochemical localization of H2O2 expressed as CeCl3 deposition at the subcellular level was observed by using transmission electron microscopy (TEM). Nox gene expression in sclerotia and mycelia was detected by quantitative real-time PCR (qRT-PCR) analysis. In addition, superoxide dismutase (SOD) and catalase (CAT) specific activities increased during sclerotial development and decreased after the antioxidant diphenyleneiodonium (DPI) was used. Results indicated that the temperature shift treatment induced P. umbellatus sclerotial formation. Compared with the mycelia, the Nox gene was respectively upregulated by 10.577-, 30.984- and 25.469-fold in the sclerotia of SI, SD and SM stages respectively. During the sclerotial formation, H2O2 accumulation was observed in the cell walls or around the organelle membranes of the mycelial cells. The antioxidant DPI decreased the generation of H2O2 in mycelial cells. The specific activity of SOD and CAT levels was decreased significantly by DPI. The activity of the two antioxidant enzymes in the mycelia increased much more during sclerotial formation (p < 0.05). Oxidative stress was closely associated with sclerotial development in P. umbellatus induced by temperature shift treatment.


Assuntos
Peróxido de Hidrogênio/metabolismo , NADPH Oxidases/genética , Estresse Oxidativo , Polyporus/ultraestrutura , Antioxidantes/farmacologia , Catalase/biossíntese , Regulação Fúngica da Expressão Gênica , Microscopia Eletrônica , Micélio/enzimologia , Micélio/crescimento & desenvolvimento , NADPH Oxidases/biossíntese , Oniocompostos/farmacologia , Polyporus/genética , Polyporus/crescimento & desenvolvimento , Superóxido Dismutase/biossíntese , Temperatura
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