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1.
Environ Res ; : 118742, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38570132

RESUMO

This study addresses the pressing need for cost-effective emission reduction strategies that maximize co-benefits in terms of air pollution and carbon emissions. Our research contributes to the literature by accurately measuring these co-benefits, thereby facilitating their prompt realization in different regions. We employ an input-output framework that integrates carbon emissions and air pollution, allowing us to calculate marginal abatement costs using the shadow price of undesired output. Through this approach, we quantify the co-benefits and analyze the factors influencing them at both spatiotemporal and factor levels using spatial kernel density and geographical detectors. Our findings reveal several key insights: (1) under joint emission reduction efforts, we observe average annual reduction rates of 6.46% for marginal pollution and 6.10% for carbon reduction costs. Importantly, we document an increase in co-benefits from 0.50 to 0.86, characterized by an initial fluctuation followed by a linear increase. (2) the marginal cost difference for carbon emission and pollution reduction in western China was 179.45 and 155.08 respectively, compared to 321.51 and 124.70 in the Northeast, highlighting the crucial role of regional differences in shaping co-benefit outcomes. (3) we identify a negative spatial spillover effect between provinces, which diminishes over time, leading to heterogeneous effects when local provincial co-benefits exceed a threshold of 0.9. (4) during the adjustment period, we find that the industrial structure exerts significant single and interactive effects on co-benefits. Additionally, we highlight the critical role of environmental governance investment and government intervention as drivers of co-benefits in the current era. By offering the quantification of co-benefits under the marginal abatement costs, our study provides valuable scientific insights for planning and implementing effective synergy strategies.

2.
Org Biomol Chem ; 22(8): 1634-1638, 2024 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-38323382

RESUMO

Alzheimer's disease (AD) is characterized by cognitive decline, often attributed to the deficiency of acetylcholine, which can undergo hydrolysis by acetylcholinesterase (AChE) within the biological milieu. Here, we report a supramolecular strategy that takes advantage of confinement effects to inhibit such a hydrolysis process, shedding some light on AD therapy. A water-soluble and bowl-shaped molecule, hexacarboxylated tribenzotriquinacene (TBTQ-C6), was employed to shield acetylcholine (G1) from enzymatic degradation through host-guest binding interactions. Our study revealed highly efficient host-guest interactions with a binding ratio of 1 : 3, resulting in a significant reduction in acetylcholine hydrolysis from 91.1% to 7.4% in the presence of AChE under otherwise identical conditions. Furthermore, TBTQ-C6 showed potential for attenuating the degradation of butyrylcholine (G2) by butyrylcholinesterase (BChE). The broader implications of this study extend to the potential use of molecular containers in various biochemical and pharmacological applications, opening new avenues for research in the field of neurodegenerative diseases.


Assuntos
Doença de Alzheimer , Butirilcolinesterase , Humanos , Butirilcolinesterase/metabolismo , Acetilcolina/metabolismo , Acetilcolina/uso terapêutico , Acetilcolinesterase/metabolismo , Hidrólise , Doença de Alzheimer/tratamento farmacológico , Inibidores da Colinesterase/química , Simulação de Acoplamento Molecular
3.
J Exp Psychol Hum Percept Perform ; 49(9): 1203-1220, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37471003

RESUMO

Handling imperfect information problems is fundamental to perception, learning, and decision-making. Ensemble perception may partially overcome imperfect information by providing global clues. However, if not all cluster elements are readily accessible, the observations required for computing statistics are incomplete. In this case, these elements' internal correlations (i.e., regularity) could serve as clues to elucidate the missing pieces. We thus investigated spatial regularity's role in ensemble perception under imperfect information situations created using partially occluded stimuli. In two experiments, we manipulated circle size (Experiment 1) and line orientation (Experiment 2) to linearly vary with its location; spatial regularity thus supplied clues for inferring information of the invisible parts. Participants estimated the mean of the targeted feature of the entire cluster, including visible and invisible parts. We observed robust biases toward the overall cluster in the estimations, implying the invisible parts were considered during ensemble perception. We proposed this effect could be understood as assessing evidence from visible parts to construct the missing parts. Experiment 3 employed a periodicity regularity to deter participants from using specific strategies, and consistent results were found. We then developed a generative model, the Regularity-Based Model, to simulate the inference process, which better captured the pattern of human outcomes than the comparative model. These findings indicate the visual system could use high-level structural information to infer scenes with incomplete information, thus producing more accurate ensemble representations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Aprendizagem , Humanos
4.
Cogn Sci ; 47(5): e13294, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37183511

RESUMO

People are known for good predictions in domains they have rich experience with, such as everyday statistics and intuitive physics. But how well can they predict for problems they lack experience with, such as the duration of an ongoing epidemic caused by a new virus? Amid the first wave of COVID-19 in China, we conducted an online diary study, asking each of over 400 participants to predict the remaining duration of the epidemic, once per day for 14 days. Participants' predictions reflected a reasonable use of publicly available information but were meanwhile biased, subject to the influence of negative affect and future time perspectives. Computational modeling revealed that participants neither relied on prior distributions of epidemic durations as in inferring everyday statistics, nor on mechanistic simulations of epidemic dynamics as in computing intuitive physics. Instead, with minimal experience, participants' predictions were best explained by similarity-based generalization of the temporal pattern of epidemic statistics. In two control experiments, we further confirmed that such cognitive algorithm is not specific to the epidemic scenario and that minimal and rich experience do lead to different prediction behaviors for the same observations. We conclude that people generalize patterns in recent history to predict the future under minimal experience.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , Generalização Psicológica , Simulação por Computador , China/epidemiologia
5.
Beilstein J Org Chem ; 19: 635-645, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37205131

RESUMO

We synthesized a new tetraphenylethylene-modified chitosan bioconjugate, CS-TPE, that shows the aggregation-induced emission effect. It can self-assemble into fluorescent polymeric nanoparticles in an aqueous solution at pH 5.3 either alone or with the water-soluble bowl-shaped six-fold carboxylated tribenzotriquinacene derivative TBTQ-C6 via host-guest binding. The spherical nanoparticles formed by CS-TPE amphiphiles or TBTQ-C6/CS-TPE supra-amphiphiles disintegrated under alkaline stimulation at pH 10.4 and the dispersion of the aggregates after the collapse in the presence of TBTQ-C6 was greatly improved. In addition, the fluorescence of CS-TPE was significantly enhanced by introducing TBTQ-C6, and remained relatively stable with variations in pH for both CS-TPE and TBTQ-C6/CS-TPE. Such pH-responsive supramolecular spherical nanoparticles with stable fluorescence emission based on CS-TPE or TBTQ-C6/CS-TPE may find applications in various fields, including the development of visual oral drug delivery systems.

6.
Mol Psychiatry ; 27(8): 3214-3222, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35668158

RESUMO

Infectious disease epidemics have become more frequent and more complex during the 21st century, posing a health threat to the general public and leading to psychological symptoms. The current study was designed to investigate the prevalence of and risk factors associated with depression, anxiety and insomnia symptoms during epidemic outbreaks, including COVID-19. We systematically searched the PubMed, Embase, Web of Science, OVID, Medline, Cochrane databases, bioRxiv and medRxiv to identify studies that reported the prevalence of depression, anxiety or insomnia during infectious disease epidemics, up to August 14th, 2020. Prevalence of mental symptoms among different populations including the general public, health workers, university students, older adults, infected patients, survivors of infection, and pregnant women across all types of epidemics was pooled. In addition, prevalence of mental symptoms during COVID-19 was estimated by time using meta-regression analysis. A total of 17,506 papers were initially retrieved, and a final of 283 studies met the inclusion criteria, representing a total of 948,882 individuals. The pooled prevalence of depression ranged from 23.1%, 95% confidential intervals (95% CI: [13.9-32.2]) in survivors to 43.3% (95% CI: [27.1-59.6]) in university students, the pooled prevalence of anxiety ranged from 25.0% (95% CI: [12.0-38.0]) in older adults to 43.3% (95% CI: [23.3-63.3]) in pregnant women, and insomnia symptoms ranged from 29.7% (95% CI: [24.4-34.9]) in the general public to 58.4% (95% CI: [28.1-88.6]) in university students. Prevalence of moderate-to-severe mental symptoms was lower but had substantial variation across different populations. The prevalence of mental problems increased over time during the COVID-19 pandemic among the general public, health workers and university students, and decreased among infected patients. Factors associated with increased prevalence for all three mental health symptoms included female sex, and having physical disorders, psychiatric disorders, COVID infection, colleagues or family members infected, experience of frontline work, close contact with infected patients, high exposure risk, quarantine experience and high concern about epidemics. Frequent exercise and good social support were associated with lower risk for these three mental symptoms. In conclusion, mental symptoms are common during epidemics with substantial variation across populations. The population-specific psychological crisis management are needed to decrease the burden of psychological problem and improve the mental wellbeing during epidemic.


Assuntos
COVID-19 , Doenças Transmissíveis , Distúrbios do Início e da Manutenção do Sono , Gravidez , Feminino , Humanos , Idoso , COVID-19/epidemiologia , Pandemias , Distúrbios do Início e da Manutenção do Sono/epidemiologia , Prevalência , Depressão/epidemiologia , Depressão/etiologia , SARS-CoV-2 , Ansiedade/epidemiologia , Ansiedade/etiologia , Fatores de Risco , Doenças Transmissíveis/epidemiologia
7.
Int J Gen Med ; 15: 4793-4805, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35592543

RESUMO

Purpose: The inflammatory response was associated with the prognosis of head and neck squamous cell carcinoma (HNSCC). This study aimed to perform a novel prognostic signature based on inflammation-related genes (IRGs) for a better understanding of the prognosis of HNSCC. Patients and Methods: IRGs were obtained from The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) database. Functional enrichment analysis was performed to explore potential pathways. Univariate and multivariate Cox regression as well as the Least Absolute Shrinkage and Selection Operator (LASSO) were utilized to construct an IRGs-based prognostic model on TCGA database and the GEO database was utilized for outcome validation. The nomogram model was constructed based on independent prognostic factors after univariate and multivariate Cox regression. The immune cell infiltration level was analyzed via the Tumor Immune Estimation Resource (TIMER) database. Results: In this study, we confirmed that 60% IRGs were abnormally expressed in HNSCC samples, and these were associated with important oncobiology. Then, a prognostic signature comprising 7 hub genes was generated based on TCGA database. The results were validated in 97 patients from GSE41613. A nomogram comprising risk score, age, M stage and N stage was generated to improve the accuracy of prognosis evaluation. The immune cell infiltration analysis suggested that 5 hub genes (ADGRE1, OLR1, TIMP1, GPR132 and CCR7) were negatively correlated with tumor purity and positively correlated with the infiltration of immune cells. Conclusion: Our study established a novel signature consisting of 7 hub genes for the prognostic prediction in patients with HNSCC.

8.
Postgrad Med J ; 98(1155): 57-66, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33574180

RESUMO

Recurrent aphthous stomatitis (RAS) is the most common disease of oral mucosa, which almost attacks each individual once in their lifespan. Although plenty of factors have been suggested to play a role in the pathogenesis of RAS, the aetiology of RAS is still controversial, which might lead to limited clinical therapies in accordance with each RAS patient. This review mainly illustrates recent advances in potential causes associated with RAS in detail. Deeper comprehension of the aetiology of RAS will support doctors and researchers to make a better management of RAS patients and to discover new treatments. The aetiology of RAS is complicated, hence we should take a comprehensive view into its aetiology, with multiple potential factors being considered. Sample collection of RAS patients have greatly limited the progress in the aetiology of RAS. A research model of multiagency cooperation can help achieve perfect sample collection of year-round and multiposition.


Assuntos
Estomatite Aftosa/epidemiologia , Estomatite Aftosa/etiologia , Causalidade , Humanos , Mucosa Bucal , Recidiva , Estomatite Aftosa/terapia
9.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 29(3): 819-826, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34105478

RESUMO

OBJECTIVE: To investigate the effect of complement C3 on the prognosis of patients with multiple myeloma (MM), and to establish a predictive model to evaluate the overall survival. METHODS: Eighty newly diagnosed MM patients were enrolled, and clinical characteristics, such as sex, age, platelet count, white blood cell count, ISS stage, FISH, levels of kappa and lammda chain, complement C3 and C4 were retrospectively analyzed. Cox regression model was used for univariate and multivariate analysis about risk factors that affecting the prognosis of the MM patients. A nomogram based on C3 level was established for predicting the prognosis of MM patients. RESULTS: The average age of the MM patients was 63.15±10.41, including 36 males and 44 females. The median overall survival (OS) was 36.3 months, and the median progression-free survival (PFS) was 35.2 months, the 3-year OS rate and PFS rate of the MM patients were 67.5% and 52.5%, respectively. The variants selected by univariate analysis were put into multivariate regression model, the result showed that C3 level ≥0.7 U/L and PLT count <100×109/L were the independent risk factors for OS. Nomogram based on C3 level, PLT count as well as ß2-protein level showed an excellent accuracy in estimating prognosis of MM (C-index: 0.775). CONCLUSION: Patients with C3 level≥0.7 U/L or PLT count <100×109/L show poor prognosis. Nomogram based on the two variants can estimate overall survival of MM patients and provide suggestions to clinical decision.


Assuntos
Mieloma Múltiplo , Complemento C3 , Feminino , Humanos , Masculino , Contagem de Plaquetas , Prognóstico , Estudos Retrospectivos
10.
Int J Hematol ; 114(3): 408-412, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34009622

RESUMO

Chimeric antigen receptor T (CAR-T)-cell therapy is a promising treatment for relapsed/refractory multiple myeloma (RRMM). In our previous report, CD19- and BCMA-targeted CAR-T co-administration was associated with a high response rate. Although cytokine release syndrome (CRS) and neurotoxicity are frequent complications following CAR-T treatment, cerebral infarction is rarely reported as a CAR-T-related complication. We reported a 73-year-old female MM patient who received CD19- and BCMA-targeted CAR-T for refractory disease. Her disease responded to CAR-T therapy, but she developed neurological symptoms following CRS. Cranial CT and MRI demonstrated multiple cerebral infarctions and bilateral anterior cerebral artery (ACA) occlusion. We suggest that cerebral infarction other than CAR-T-related neurotoxicity is the underlying cause of abnormal neuropsychological symptoms, and diagnostic imaging tests should be actively performed to exclude ischemic cerebrovascular events.


Assuntos
Antígeno de Maturação de Linfócitos B/antagonistas & inibidores , Infarto Encefálico/diagnóstico , Infarto Encefálico/etiologia , Imunoterapia Adotiva/efeitos adversos , Mieloma Múltiplo/complicações , Mieloma Múltiplo/terapia , Idoso , Artéria Cerebral Anterior/patologia , Antígenos CD19/imunologia , Biomarcadores Tumorais , Terapia Combinada , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Mieloma Múltiplo/diagnóstico , Radiografia , Tomografia Computadorizada por Raios X , Resultado do Tratamento
11.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 25(5): 1436-1443, 2017 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-29070121

RESUMO

OBJECTIVE: To investigate the relationship of clinical related indicator levels and clinical staging with the prognosis of MM patients so as to more accurately evaluate the disease status and guide the clinical treatment. METHOD: The clinical indicators including age, WBC and Plt counts, FISH result, ISS staging, Kappa and Lammada light chain levels and so on in 57 cases of MM were analyzed retrospectively; the unvariate and multivatiate analyses of factors influencing the prognosis of MM patients were performed by Kaplan-Meier and Cox regression model; the factors influencing the prognosis of patients were evaluated. RESULTS: Median age of 57 patients including 25 male and 32 female, was 63(29-81) years old, mean OS time was 37.3 months, mean PFS time was 36.3 months, 3-year OS and PFS were 73.6% and 56.1% respectively. The unvaviate analysis showed that age, WBC count, Plt count, FISH result, ISS staging, Kappa and lammda light chain levels, and remission were factors influencing the prognosis; the multivatiate analysis showed that the Kappa light chain level ≥19.4 mg/L and Plt count <100×109/L were independant risk factors influencing the prognosis of MM patients. CONCLUSION: The prognosis of MM patients with high Kappa light chian level and low Plt count is very poor, therefore the therapeutic regimens should be selected differentially for this kind of newly diagnosed MM patients so as to enhance the survival time of patients.


Assuntos
Cadeias kappa de Imunoglobulina , Mieloma Múltiplo/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/patologia , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida
12.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 23(5): 1400-3, 2015 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-26524046

RESUMO

OBJECTIVE: To study the therapeutic efficacy of multigly-cosidorum Tripterygium combined with rhIL-11 for treating patients with immune thrombocytopenia (ITP). METHODS: A total of 75 patients with ITP were divided into 2 group: experimental group and control group. The experimental group included 40 patients who had been treated with multigly-cosidorum Tripterygium combined with rhIL-11. Multigly-cosidorum Tripterygium was given at a dose of 1mg/kg·d for 2 months and rhIL-11 was injected at a dose of 16,000,000 units per day. Control group included 35 patients who had been treated with prednisone at a dose of 1 mg/kg·d. Platelet counts were performed every day before platelet counts >30 × 109/L. Peripheral blood T cells were collected before and after treated for 2 months. The ratios of CD4⁺, CD8⁺ T cells in peripheral blood T cells were analyzed by flow cytometry. RESULTS: Totally effective rate in experimental group was 77.5%. Totally effective rate in control group was 82.9%. Totally effective rate showed no statistical difference between these two groups (P > 0.05). The average time of platelet count 30 × 109/L in experimental and control groups were 13.06 ± 6.10 days and 9.76 ± 5.71 days respectively; in experimental group, the ratio of CD4⁺ T cells in peripheral blood was 21.03% before treatment, then rised to 34.49% after treatment for 2 months (P < 0.01); The ratio of CD8⁺ T cells in peripheral blood was 26.35% before treatment, then decreased to 20.18% (P < 0.01). In control group, the ratio of CD4⁺ T cells was 22.30% before treatment, then rised to 25.11% after treatment for 2 months (P < 0.05); The ratio of CD8⁺ T cells in peripheral blood was 27.24% before treatment, then decreased to 21.35% (P < 0.01). CONCLUSION: Multigly-cosidorum tripterygium can correct disorder of T lymphocytes, the combination of multigly-cosidorum triptergium and rhIL-11 can accelerate therapeutic efficacy for treating ITP and with less adverse reaction, so this combination may be effective and safe for treating patients with ITP.


Assuntos
Antineoplásicos/uso terapêutico , Medicamentos de Ervas Chinesas/uso terapêutico , Interleucina-11/uso terapêutico , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Tripterygium/química , Humanos , Contagem de Plaquetas , Proteínas Recombinantes/uso terapêutico , Linfócitos T
13.
Clin Lymphoma Myeloma Leuk ; 15(1): e15-21, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25131854

RESUMO

BACKGROUND: POEMS syndrome, a rare paraneoplastic disease, is related to multiple organs, multiple systems, and multiple disciplines and can be mistaken for other disorders. Consequently, the diagnoses are often delayed. In this work we studied the clinicopathologic characteristics of the POEMS syndrome to improve early diagnosis to prevent irreversible damage. PATIENTS AND METHODS: We conducted a clinicopathologic analysis of 9 cases of POEMS and made a differential diagnosis with related diseases. RESULTS: The patients with POEMS syndrome were shown to have complicated clinical characteristics, including peripheral neuropathy, organomegaly, endocrinopathy, monoclonal plasma proliferative disorder, skin changes, extravascular volume overload, sclerotic bone lesions, thrombocytosis, and Castleman disease. POEMS syndrome shared many elements with other diseases and the key way to differentiate them was to determine whether there were other fundamental POEMS syndrome symptoms or signs. The level of M-protein in serum and plasma cells in bone marrow of POEMS patients was lower than that of patients with multiple myeloma (MM). Sclerotic bone lesions were a distinctive feature in patients with POEMS, compared with in those with MM. CONCLUSION: Some unique clinicopathologic characteristics of POEMS syndrome can be used for differential diagnosis. This study provides increased awareness of POEMS syndrome.


Assuntos
Síndrome POEMS/diagnóstico , Adulto , Medula Óssea/patologia , Osso e Ossos/patologia , Diagnóstico Diferencial , Feminino , Humanos , Linfonodos/patologia , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/diagnóstico , Síndrome POEMS/patologia , Doenças do Sistema Nervoso Periférico/diagnóstico , Derrame Pleural/diagnóstico por imagem , Pele/patologia , Tomografia Computadorizada por Raios X
15.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 16(4): 755-8, 2008 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-18718054

RESUMO

The purpose of this study was to investigate the growth characteristics and the expression level of integrin mRNA of the cultured bone marrow mesenchymal stem cells (BMMSCs) from patients with chronic myeloid leukemia (CML) in myeloid crisis (MC), and explore the role of BMMSCs in pathogenesis of CML. Five CML patients were enrolled in experimental group, five healthy persons were used as control. BMMSCs were cultured in vitro. The morphology of BMMSCs was observed every day and the growth curve were portrayed, and the ability of cell proliferation were detected according to the daily results of cell counting. Total RNA was extracted from third and fourth passages of BMMSCs, The expression of integrins mRNA of BMMSCs were measured by real-time PCR. The results showed that the BMMSCs of experimental and control groups had no difference in growth characterisctics, but the expression of integrins mRNA of the BMMSCs was higher in CML patients than in normal control group (p < 0.05). It is concluded that the abnormally high expression of integrins of BMMSC from the CML patients take part in pathogenesis of CML.


Assuntos
Células da Medula Óssea/metabolismo , Integrinas/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Células-Tronco Mesenquimais/metabolismo , Adulto , Crise Blástica/metabolismo , Células da Medula Óssea/patologia , Proliferação de Células , Feminino , Humanos , Integrinas/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Masculino , Células-Tronco Mesenquimais/patologia , Pessoa de Meia-Idade , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Células Tumorais Cultivadas
16.
Inorg Chem ; 46(24): 10044-6, 2007 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-17958359

RESUMO

An alpha-quartz-mimetic chiral coordination network of [Ag(L1)(CF3SO3)]n (L1=5,5'-bipyrimidine), after treatment with PF6- anions, undergoes a solution-state structural transformation toward [Ag(L1)(PF6)]n with a cristobalite-mimetic chiral structures. This structural transformation is accompanied by substantial enhancement in the fluorescent intensity and in the second-harmonic-generation response. The results also demonstrate an effective design strategy based on the spontaneous resolution route for the preparation of chiral architectures.


Assuntos
Compostos Organometálicos/síntese química , Quartzo/química , Dióxido de Silício/química , Prata/química , Estrutura Molecular , Compostos Organometálicos/química
17.
Inorg Chem ; 45(6): 2430-7, 2006 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-16529462

RESUMO

A 0D discrete molecule [Co(3,5-pdc)(H2O)5].2H2O (1) was obtained in quantitative yield from the reaction of CoCl2.6H2O and pyridine-3,5-dicarboxylate (3,5-pdc) in pure water solvent at ambient temperature. While a 1D zigzag chain species, [{Co(3,5-pdc)(H2O)4}.H2O]n (2), was produced in a water-rich environment, a 2D layer compound, [Co(3,5-pdc)(H2O)2]n (3), with a 6(3) topology was generated under a water-reduced condition and a 2D sheet structure, [{Cu(3,5-pdc)(py)2}.H2O.EtOH]n (4), was formed under a water-poor condition. Compounds 1, 2, and 4 were characterized by single-crystal X-ray diffraction analysis. The 1D zigzag chain 2 shows a recoverable collapsing property. Compound 4 adopts a 2D sheet structure with a 4.8(2) topology, observed for the first time for the 3,5-pdc-related metal-organic frameworks. Water content was found to be an important factor in determining the topologies of the products in the self-assembly of divalent metal ions (Co2+, Cu2+) and pyridine-3,5-dicarboxylate under mild conditions.

18.
Inorg Chem ; 41(9): 2592-7, 2002 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-11978131

RESUMO

The synthesis and characterization of a cadmium(II) coordination polymer, [Cd(C(12)H(6)N(2)O(4)) x H(2)O](n)() (1), is reported. A single-crystal X-ray analysis shows that compound 1 presents a non-interpenetrating three-dimensional porous host containing one-dimensional hydrophilic channels, where guest water molecules reside. The strategy in designing the 3-D framework architecture is based on a combination of two building subunits: a porous two-dimensional grid of (4,4) topology and a metal dicarboxylate cluster chain. Both subunits are assembled from the coordination of a cadmium ion with a three-connecting organic modular ligand, 2,2'-bipyridyl-4,4'-dicarboxylic acid (H(2)bpdc). The results of thermogravimetric analysis and powder X-ray diffraction study show that the framework rigidity of compound 1 remains intact upon the removal of guest molecules, and maintains the thermal stability up to 440 degrees C. The second-row transition-metal ions are capable of engaging higher coordination modes (e.g., hepta- and octacoordination) because of their atomic sizes and intrinsic electron configurations. Our results show that the heptacoordinated cadmium center plays an important role in the overall framework rigidity and high thermal stability of compound 1. Crystal data for 1: Cd(C(12)H(6)N(2)O(4)) x H(2)O, triclinic, space group P1 macro, a = 6.7843(5) A, b = 9.3299(7) A, c = 9.4439(7) A, alpha = 104.629(1) degrees, beta = 92.324(1) degrees, gamma = 100.416(1) degrees, Z = 2.

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