RESUMO
Gastric cancer is one of the most common malignancies worldwide. Interleukin-1-beta (IL-1ß) is a pro-inflammatory cytokine and potent inhibitor of gastric acid secretion. Some studies provided evidence of the association between IL-1B 31 polymorphism and gastric cancer risk while other studies did not. Therefore, we conducted a comprehensive meta-analysis to reassess the association. A systematic literature search of the PubMed and EMBASE databases identified 37 studies with 6108 cases and 8980 controls for this meta-analysis. The crude odd ratios (ORs) and the 95% confidence intervals (CIs) were calculated to evaluate the strength of the association. Meta-regression was used to determine the major source of heterogeneity across the studies. The pooled analysis did not suggest the significant association of IL-1B 31 C>T polymorphism with gastric cancer risk. Stratified analysis was performed by ethnicity, source of control, genotype method, and indicated a significantly increased gastric cancer risk associated with IL-1B 31T variant in the population-based subgroup (heterozygous model: OR = 1.22, 95% CI = 1.03-1.45). Moreover, stratified analysis by Helicobacter pylori infection status indicated that IL-1B 31 polymorphism increased gastric cancer risk in infection-positive subgroup (homozygous model: OR = 1.35, 95% CI = 1.02-1.78; heterozygous model: OR = 1.31, 95% CI = 1.04-1.66; recessive model: OR = 1.29, 95% CI = 1.04-1.61). The study suggested that IL-1B 31 polymorphism might confer susceptibility to gastric cancer in the presence of H. pylori infection, indicating a gene-environment interaction in gastric carcinogenesis.
Assuntos
Infecções por Helicobacter/genética , Helicobacter pylori/fisiologia , Interleucina-1beta/genética , Neoplasias Gástricas/genética , Estudos de Casos e Controles , Interação Gene-Ambiente , Estudos de Associação Genética , Predisposição Genética para Doença , Infecções por Helicobacter/microbiologia , Humanos , Polimorfismo de Nucleotídeo Único , Neoplasias Gástricas/microbiologiaRESUMO
Histidine triad nucleotide-binding protein 1 (Hint1) is a haploinsufficient tumor suppressor gene. Its role in cancer cell migration has not been previously speculated. In the current study, we examined the expression of Hint1 in metastatic and non-metastatic lymph nodes of hepatocellular carcinoma (HCC) patients and further elucidated the effect of Hint1 expression on girdin expression and phosphorylation of AKT and ERK1/2 and on the migration of HCC cells in vitro. Expression of Hint1 and girdin in primary HCC tissues and metastatic and non-metastatic lymph nodes was determined by RT-PCR assays. HepG2 cells were transfected with plasmid vectors overexpressing Hint1 or small interfering RNA (siRNA) targeting Hint1, girdin, Hint1 plus girdin, or the scrambled RNA. Migration and invasion of HCC cells were examined by wound and Transwell assays. Protein expression was detected by immunofluorescence and immunoblotting assays. RT-PCR assays revealed that the messenger RNA (mRNA) transcript levels of Hint1 were markedly lower than those of primary HCC tissues and non-metastatic lymph nodes (P < 0.01). By contrast, the mRNA transcript levels of girdin were significantly higher than non-metastatic lymph nodes (P < 0.05). Furthermore, siRNA knockdown of HINT1 resulted in a significant increase in the mRNA transcript levels of girdin in HepG2 cells (P < 0.05). Wound assays and Transwell assays showed that Hint1 knockdown by siRNA significantly enhanced the migration and invasion of HepG2 cells compared to HepG2 cells transfected with scrambled siRNA. Hint1 knockdown also led to significantly increased phosphorylation of girdin and AKT in HepG2 cells (P < 0.05), which, however, was effectively aborted by girdin knockdown by siRNA (P < 0.05). Hint1 is downregulated in metastatic lymph nodes and is implicated in migration and invasion of HCC cells in vitro by modulating girdin and AKT expression and phosphorylation. The Hint1-girdin-AKT signaling axis should be further dissected for its role in HCC migration and invasion and may be therapeutically targeted to suppress tumor growth and metastasis.
Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/secundário , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/patologia , Proteínas dos Microfilamentos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Apoptose , Biomarcadores Tumorais/genética , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Movimento Celular , Proliferação de Células , Feminino , Citometria de Fluxo , Humanos , Técnicas Imunoenzimáticas , Técnicas In Vitro , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Metástase Linfática , Masculino , Proteínas dos Microfilamentos/genética , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Proteínas do Tecido Nervoso/genética , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Células Tumorais Cultivadas , Proteínas de Transporte Vesicular/genéticaRESUMO
Metal-organic frameworks (MOFs) as types of proton conductive materials have attracted much attention. Here, an acylamide-functionalized 3D MOF, [Ni3(TPBTC)2(stp)2(H2O)4]·2DMA·32H2O, has been successfully constructed via combining Ni(NO3)2, TPBTC (TPBTC = benzene-1,3,5-tricarboxylic acid tris-pyridin-4-ylamide) and 2-H2stp (2-H2stp = 2-sulfoterephthalic acid monosodium salt) under solvothermal conditions. Single-crystal X-ray diffraction revealed that there are uncoordinated guest DMA molecules in the pores of the compound. On removal of guest DMA molecules, the proton conductivity of the compound increased to 2.25 × 10-3 S cm-1 at 80 °C and 98% RH which is about 110 times that of the original material. It is hoped that this work can provide essential insight for designing and obtaining improved crystalline-state proton conducting materials by considering the influences of guest molecules on proton conduction properties of porous materials.
RESUMO
The NH(2) group in primary allylic amines was substituted directly by sulfinate salts with excellent regio- and stereoselectivities. In the presence of 0.1 mol % [Pd(allyl)Cl](2), 0.4 mol % 1,4-bis(diphenylphosphino)butane (dppb), and excess boric acid, a range of α-unbranched primary allylic amines were smoothly substituted with sodium sulfinates in an α-selective fashion to give structurally diverse allylic sulfones in good to excellent yields with exclusive E selectivity. Replacing dppb with 1,1'-bi-2-naphthol (BINOL) allowed unsymmetric α-chiral primary allylic amines to be transformed into the corresponding allylic sulfones in good to excellent yields with excellent retention of ee. Importantly, the reaction complements known asymmetric methods in substrate scope via its unique ability to provide α-chiral allylic sulfones with high optical purity starting from unsymmetric allylic electrophiles.
Assuntos
Compostos Alílicos/química , Aminas/química , Ácidos Sulfínicos/química , Sulfonas/síntese química , Compostos Alílicos/síntese química , Estrutura Molecular , Sais/química , Estereoisomerismo , Sulfonas/químicaRESUMO
Three new cucurbit[6]uril (CB[6])-based metal-organic rotaxane networks (MORNs) (named CUST-711, CUST-712, and CUST-713) functionalized by a sulfonic group (-SO3H) have been designed and synthesized via a hydrothermal method. All three compounds exhibited similar two-dimensional (2D) wave layer structures. Their stability under different temperature and relative humidity conditions has been investigated and all the compounds showed excellent stability. Furthermore, their proton conduction properties were also discussed in detail. Due to different structures and sulfonic group sites, the three compounds exhibited different proton conduction abilities of which CUST-712 exhibited an intrinsic relatively high proton conductivity (1.75 × 10-4 S cm-1 at 85 °C and 97% relative humidity). These results provide ideas for the design and synthesis of functional CB[6]-based metal-organic rotaxane frameworks (MORFs) as proton conducting materials.
RESUMO
OBJECTIVE: To study the regulatory rolesof SIRT1 on EZH2 expression and the further effects on EZH 2' s repression of target gene expression. METHODS: The stable SIRT1 RNAi and Control RNAi HeLa cells were established by infection with retroviruses expressing shSIRT1 and shLuc respectively followed by puromycin selection. EZH2 protein level was detected by Western blot in either whole cell lysate or the fractional cell extract. Reverse transcription-polymerase chain reaction was performed to detect the mRNA level of EZH2. Cycloheximide was used to treat SIRT1 RNAi and Control RNAi cells for protein stability assay. Chromatin immunoprecipitation(ChIP) assay was applied to measure enrichment of SIRT1, EZH2, and trimethylated H3K27 (H3K27me3) at SATB1 promoter in SIRT1 RNAi and Control RNAi cells. RESULTS: Western blot results showed that EZH2 protein level increased upon SIRT1 depletion. Fractional extraction results showed unchanged cytoplasmic fraction and increased chromatin fraction of EZH2 protein in SIRT1 RNAi cells. The mRNA level of EZH2 was not affected by knockdown of SIRT1. SIRT1 recruitment was not detected at the promoter regionof EZH2 gene locus. The protein stability assay showed that the protein stability of EZH2 increases upon SIRT1 knockdown. Upon SIRT1 depletion, EZH2 and H3K27me3 recruitment at SATB1 promoter increases and the mRNA level of SATB1 decreases. CONCLUSIONS: Depletion of SIRT1 increases the protein stability of EZH2. The regulation of EZH2 protein level by SIRT1 affects the repressive effects of EZH2 on the target gene expression.
Assuntos
Proteínas de Ligação a DNA/fisiologia , Proteínas Repressoras/fisiologia , Sirtuína 1/fisiologia , Fatores de Transcrição/fisiologia , Proteínas de Ligação a DNA/análise , Proteínas de Ligação a DNA/química , Proteína Potenciadora do Homólogo 2 de Zeste , Regulação da Expressão Gênica , Células HeLa , Humanos , Complexo Repressor Polycomb 2 , Sirtuína 1/antagonistas & inibidores , Fatores de Transcrição/análise , Fatores de Transcrição/químicaRESUMO
Two new cucurbit[6]uril (CB[6])-based metal-organic rotaxane networks (MORNs) were successfully obtained by tuning the coordination sphere of metal copper clusters. Compounds 1 and 2 exhibited relatively high proton conductivity at 85 °C and 97% relative humidity (RH), providing great promise for fuel cell electrolyte materials.
RESUMO
RNA polymerases can be shared by a particular group of genes in a transcription "factory" in nuclei, where transcription may be coordinated in concert with the distribution of coexpressed genes in higher-eukaryote genomes. Moreover, gene expression can be modulated by regulatory elements working over a long distance. Here, we compared the conformation of a 130-kb chromatin region containing the mouse alpha-globin cluster and their flanking housekeeping genes in 14.5-day-postcoitum fetal liver and brain cells. The analysis of chromatin conformation showed that the active alpha1 and alpha2 globin genes and upstream regulatory elements are in close spatial proximity, indicating that looping may function in the transcriptional regulation of the mouse alpha-globin cluster. In fetal liver cells, the active alpha1 and alpha2 genes, but not the inactive zeta gene, colocalize with neighboring housekeeping genes C16orf33, C16orf8, MPG, and C16orf35. This is in sharp contrast with the mouse alpha-globin genes in nonexpressing cells, which are separated from the congregated housekeeping genes. A comparison of RNA polymerase II (Pol II) occupancies showed that active alpha1 and alpha2 gene promoters have a much higher RNA Pol II enrichment in liver than in brain. The RNA Pol II occupancy at the zeta gene promoter, which is specifically repressed during development, is much lower than that at the alpha1 and alpha2 promoters. Thus, the mouse alpha-globin gene cluster may be regulated through moving in or out active globin gene promoters and regulatory elements of a preexisting transcription factory in the nucleus, which is maintained by the flanking clustered housekeeping genes, to activate or inactivate alpha-globin gene expression.
Assuntos
Cromatina/química , Regulação da Expressão Gênica , Globinas/genética , Região de Controle de Locus Gênico/genética , Transcrição Gênica , Animais , Encéfalo/metabolismo , Núcleo Celular/metabolismo , Cromatina/metabolismo , Ordem dos Genes , Fígado/metabolismo , Camundongos , Regiões Promotoras Genéticas , Conformação Proteica , RNA Polimerase II/metabolismoRESUMO
Three new high-dimensional cucurbit[6]-based metal-organic rotaxane frameworks [Co2(PR43)(BDC)2Cl2]·4H2O (1), [Co2(PR43)(BTC)2]·6H2O (2) and [Co2(PR43)(BPT)2]·20H2O (3) were obtained via the hydrothermal synthesis method. Compound 1 comprised a two-dimensional layered structure, while compounds 2 and 3 exhibited three-dimensional pillared structures. All the compounds showed good thermal stabilities. Furthermore, the magnetic properties of compounds 1-3 were also investigated in detail.
RESUMO
A prospective observational study collected temperature data from 51 patients in 11 neurosurgical centers and follow-up outcome information at 6 months in 49 patients. Brain temperature (Tbr) was measured directly by an intraventricular temperature sensor. Axillary temperature (Tax) and rectal temperature (Tre) were measured by electric thermometers. Tbr was 0.4 to 1.5°C higher than body temperature. Tre correlated well with the Tbr (coefficient: 0.7378; p < 0.05). Among all patients, Glasgow Coma Scale (GCS) scores on admission were significantly lower in the patients with post-operatively extreme peak temperature (Tpeak, < 37°C or >39°C in first 24 h) and major temperature variation (Tvari > 1°C in first 12 h; p < 0.05, p < 0.01, respectively). Among the patients with no temperature intervention, the extreme Tpeak group showed a lower Glasgow Outcome Scale-Extended (GOS-E) score at 6 months (p < 0.05) with lower GCS scores on admission (p < 0.01), compared with the moderate Tpeak group. Remarkably, the major Tvari group showed significantly lower GOS-E scores (p < 0.05) with the same GCS scores as the minor Tvari group. Thus, Tre is the better candidate to estimate Tbr. Spontaneously extreme Tpeak in TBI represents both more serious injury on admission and worse prognosis, and Tvari might be used as a novel prognostic parameter in TBI. Brain temperature is therefore one of the critical indicators evaluating injury severity, prognostication, and monitoring in the management of TBI. This prospective observational study has been registered in ClinicalTrials.gov ( https://clinicaltrials.gov ), and the registration number is NCT03068143.
Assuntos
Temperatura Corporal/fisiologia , Lesões Encefálicas Traumáticas/fisiopatologia , Lesões Encefálicas Traumáticas/terapia , Encéfalo/fisiopatologia , Adulto , Idoso , Feminino , Escala de Coma de Glasgow , Escala de Resultado de Glasgow , Humanos , Hipotermia Induzida , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos ProspectivosRESUMO
Evidences indicate that locus control region (LCR) of beta-globin spatially closes to the downstream active gene promoter to mediate the transcriptional activation by looping. DNA binding proteins may play an important role in the looping formation. NF-E2 is one of the key transcription factors in beta-globin gene transcriptional activation. To shed light on whether NF-E2 is involved in this process, DS19MafKsiRNA cell pools were established by specifically knocked down the expression of MafK/NF-E2 p18, one subunit of NF-E2 heterodimer. In the above cell pools, it was observed that the occupancy efficiency of NF-E2 on beta-globin gene locus and the expression level of beta-globin genes were decreased. H3 acetylation, H3-K4 methylation and the deposition of RNA polymerase II, but not the recruitment of GATA-1, were also found reduced at the beta-globin gene cluster. Chromosome Conformation Capture (3C) assay showed that the cross-linking frequency between the main NF-E2 binding site HS2 and downstream structural genes was reduced compared to the normal cell. This result demonstrated that MafK/NF-E2 p18 recruitment was involved in the physical proximity of LCR and active beta-globin genes upon beta-globin gene transcriptional activation.
Assuntos
Regulação da Expressão Gênica/fisiologia , Globinas/genética , Região de Controle de Locus Gênico/fisiologia , Fator de Transcrição MafK/fisiologia , Animais , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , DNA Polimerase II/fisiologia , Fator de Transcrição GATA1/fisiologia , Inativação Gênica , Globinas/biossíntese , Histonas/metabolismo , Camundongos , Interferência de RNARESUMO
Chromatin from different regions of the genome frequently forms steady associations that play important roles in regulating gene expression. The widely used chromatin conformation capture (3C) assay allows determination of the in vivo structural organization of an active endogenous locus. However, unpredicted chromatin associations within a given genomic locus can not be identified by 3C. Here, we describe a new strategy, quantitative associated chromatin trap (QACT), which incorporates a modified 3C method and a quantitative assay tool, to capture and quantitatively analyzes all possible associated chromatin partners (ACPs) of a given chromatin fragment. Using QACT, we have analyzed the chromatin conformation of the mouse alpha-globin gene cluster and proved the extensive interaction between HS26 and alpha-globin genes. In addition, we have identified a candidate alpha1-globin gene specific silencer 475A8 which shows the differentiation-stage specific DNase I hypersensitivity. Functional analysis suggests that 475A8 may regulate the alpha1-globin gene during terminal differentiation of committed erythroid progenitor cells. ChIP (chromatin immunoprecipitation) and cotransfection assays demonstrate that GATA-1, a hemopoietic specific transcriptional factor, may increase alpha1-globin gene expression by suppressing the function of 475A8 in terminally differentiated erythroid cells.
Assuntos
Cromatina/genética , Globinas/genética , Família Multigênica/genética , Sequências Reguladoras de Ácido Nucleico/genética , Acetilação , Animais , Linhagem Celular , Desoxirribonuclease I/metabolismo , Fator de Transcrição GATA1/metabolismo , Histonas/metabolismo , Camundongos , Ligação Proteica , Especificidade por SubstratoRESUMO
Targeted gene repair mediated by single-stranded DNA oligonucleotides (SSOs) is a promising method to correct the mutant gene precisely in prokaryotic and eukaryotic systems. We used a HeLa cell line, which was stably integrated with mutant enhanced green fluorescence protein gene (mEGFP) in the genome, to test the efficiency of SSO-mediated gene repair. We found that the mEGFP gene was successfully repaired by specific SSOs, but the efficiency was only approximately 0.1%. Then we synthesized a series of nonspecific oligonucleotides, which were single-stranded DNA with different lengths and no significant similarity with the SSOs. We found the efficiency of SSO-mediated gene repair was increased by 6-fold in nonspecific oligonucleotides-treated cells. And this improvement in repair frequency correlated with the doses of the nonspecific oligonucleotides, instead of the lengths. Our evidence suggested that this increased repair efficiency was achieved by the transient alterations of the cellular proteome. We also found the obvious strand bias that antisense SSOs were much more effective than sense SSOs in the repair experiments with nonspecific oligonucleotides. These results provide a fresh clue into the mechanism of SSO-mediated targeted gene repair in mammalian cells.
Assuntos
Reparo do DNA , DNA de Cadeia Simples/genética , Oligodesoxirribonucleotídeos/genética , Reparo Gênico Alvo-Dirigido/métodos , Sequência de Bases , Proteínas de Fluorescência Verde/genética , Células HeLa , HumanosRESUMO
The first CB[6]-based 3D porous metal-organic rotaxane framework is constructed by the reaction of CuCl2, terephthalic (H2BDC) and CB[6]-based [2]pseudorotaxanes ([PR44]2+·2[PF6]-) under solvothermal conditions. The structure of MORF-1 is a pillared-layer structure with 5-connected sqp topology, in which the effective free volume is 45.4% of the crystal volume. The guest molecules exchange in a single-crystal-to-single-crystal fashion, which was investigated using NMR spectroscopy and X-ray crystallography.
Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Estruturas Metalorgânicas/química , Rotaxanos/química , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Tamanho da Partícula , Porosidade , Propriedades de SuperfícieRESUMO
AIM: To evaluate the safety and efficacy of sorafenib plus transarterial chemoembolization (TACE) treatment for intermediate hepatocellular carcinoma (HCC). METHODS: Sixty-seven patients with intermediate-stage [Barcelona Clinic liver cancer stage B (BCLC-B)] HCC who were treated with sorafenib plus TACE or TACE alone between 2009 and 2011 were included in the study. Follow-up was until 2014 or patient death. Two groups were defined in the experiment: The experimental group, treated with sorafenib plus TACE, and the control group, treated with standard TACE alone. RESULTS: The Kaplan-Meier survival analysis showed that the median overall survival (mOS) of the experimental group was 35.2 mo, while that of the control group was 22.0 mo (P < 0.05). Sorafenib plus TACE showed higher incidence rates of rash, hand-foot syndrome (HFS), and hypertension (P < 0.05) than TACE treatment alone. CONCLUSION: Sorafenib plus TACE treatment for BCLC-B HCC significantly prolonged the mOS of patients compared to TACE treatment alone. The most common toxicities with sorafenib were rash (31.6%), HFS (39.5%) and hypertension (31.6%), but there were no intolerable adverse events. The Cox multivariate analysis showed that the survival of patients with BCLC-B HCC depended on the Child-Pugh classification, tumor diameter, and treatment with sorafenib plus TACE compared to TACE alone.
RESUMO
BACKGROUND: Development in higher eukaryotes involves programmed gene expression. Cell type-specific gene expression is established during this process and is inherited in succeeding cell cycles. Higher eukaryotes have evolved elegant mechanisms by which committed gene-expression states are transmitted through numerous cell divisions. Previous studies have shown that both DNase I-sensitive sites and the basal transcription factor TFIID remain on silenced mitotic chromosomes, suggesting that certain trans-factors might act as bookmarks, maintaining the information and transmitting it to the next generation. RESULTS: We used the mouse globin gene clusters as a model system to examine the retention of active information on M-phase chromosomes and its contribution to the persistence of transcriptional competence of these gene clusters in murine erythroleukemia cells. In cells arrested in mitosis, the erythroid-specific activator NF-E2p45 remained associated with its binding sites on the globin gene loci, while the other major erythroid factor, GATA-1, was removed from chromosome. Moreover, despite mitotic chromatin condensation, the distant regulatory regions and promoters of transcriptionally competent globin gene loci are marked by a preserved histone code consisting in active histone modifications such as H3 acetylation, H3-K4 dimethylation and K79 dimethylation. Further analysis showed that other active genes are also locally marked by the preserved active histone code throughout mitotic inactivation of transcription. CONCLUSION: Our results imply that certain kinds of specific protein factors and active histone modifications function as cellular memory markers for both competent and active genes during mitosis, and serve as a reactivated core for the resumption of transcription when the cells exit mitosis.
Assuntos
Fator de Transcrição GATA1/metabolismo , Globinas/genética , Mitose , Subunidade p45 do Fator de Transcrição NF-E2/metabolismo , Ativação Transcricional , Acetilação , Animais , Linhagem Celular Tumoral , Cromossomos de Mamíferos/metabolismo , Epigênese Genética , Histonas/metabolismo , Metilação , Camundongos , Regiões Promotoras GenéticasRESUMO
Polymorphisms in TP53 are involved in the progression of different types of cancer. A rare novel TP53 variant (rs78378222 A > C allele) was found via whole-genome sequencing in 2011. This variant was shown to significantly increase the risk of glioma, colorectal adenoma and prostate cancer. Functional analysis further revealed that this variant hindered TP53 expression and its downstream effect on apoptosis. Several studies have investigated the relationship between rs78378222 and cancer susceptibility. However, the results were not consistent. We conducted the first meta-analysis to give a more credible assessment on the association about this variant and cancer risk. Our meta-analysis included 34 studies consisting of 36599 cases and 91272 controls. These studies were mostly on the basis of high-grade data from Genome-wide association studies (GWASs). The results indicated that TP53 rs78378222 was significantly associated with an increased risk of overall cancer (AC vs. AA: OR = 1.511, 95% CI = 1.285-1.777). Furthermore, stratified analyses indicated that rs78378222 increased the risk of nervous system cancer, skin cancer and other cancer. To summarize, this meta-analysis suggested that rs78378222 C allele is a potent risk factor for overall cancer.
Assuntos
Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Sinais de Poliadenilação na Ponta 3' do RNA , Proteína Supressora de Tumor p53/genética , Estudos de Casos e Controles , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Neoplasias/patologia , Razão de Chances , Fenótipo , Medição de Risco , Fatores de RiscoRESUMO
Three polyoxovanadate-based metal-organic polyhedra (denoted as VMOP-1, -2, and -3), adopting isostructural discrete octahedral cage geometries, were successfully synthesized under solvothermal conditions. These structures are all built up from the same pentavanadate {V5O9Cl} cluster connected by linear bidentate ligands (H2L1 = H2BDC, H2L2 = H2BDC-NH2, H2L3 = H2BDC-Br), respectively.
RESUMO
A unique three-dimensional metal azolate framework containing a tetranuclear copper cluster constructed by six 1,2,4-triazole units was synthesized in which the 1,2,4-triazole units show unusual bridging "crevice" coordination mode with their 1- and 2-positioned sp(2) N-atoms as symmetrically bridging centers. The photocatalytic activities of as-prepared compound were tested by degradation of rhodamine-B (RB) under different light irradiation.
RESUMO
Two unprecedented homochiral enantiomers based on two different kinds of rigid ligands, namely [Cd(NDC)L]2·H2O (1R and 1L), have been synthesized under hydrothermal conditions through spontaneous resolution. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR, and thermogravimetric (TG) analysis. The resulting framework 1, constructed by four kinds of homo-handed helical chains represents the first 3D self-penetrating framework formed by decoration of single (10,3)-a net with helical chains. The single (10,3)-a net in 1 formed by three kinds of different homo-handed helical chains is different from the standard one, which should be ascribed to the usage of V-shaped ligand L. A unique self-penetration motif can be discovered in 1 where one helical chain alternately passes through 10-membered shortest circuits linked to each other and in contrary, the corresponding circuits are bound to the helical chain. Interestingly, 1 exhibits fluorescent emission in both the solid and solution phase. The uncoordinated nitrogen atom and amino group from the triazole core on the crystal surface make it suitable to detect picric acid in water. The luminescence intensity of 1 in water can be efficiently quenched by the addition of picric acid (PA). The sensitive detection of PA can be continuously performed for at least five cycles without diminishing the fluorescence intensity and destroying the framework structure of 1. The possible quenching mechanisms for PA are also investigated.