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OBJECTIVE: To investigate the expression level of urothelial carcinoembryonic antigen 1 (lncRNA UCA1) in the bone marrow of acute myeloid leukemia (AML) patients, and to explore the clinical significance of lncRNA UCA1 expression level in AML patients. METHODS: Bone marrow samples of 50 AML patients were collected as experimental group, and bone marrow samples of 20 iron deficiency anemia (IDA) patients were collected as control group. The relevant clinicopathological characteristics of AML patients were collected. Real-time quantitative PCR (qRT-PCR) was used to detect the expression level of lncRNA UCA1 in the experimental and control groups, and the relationships between lncRNA UCA1 expression and clinical pathological characteristics and prognosis in AML patients were analyzed. Kaplan-Meier curves were used to analyze the effect of lncRNA UCA1 on the overall survival (OS) of AML patients; And Cox regression model was used to analyze the factors affecting the prognosis of AML patients. RESULTS: Compared with the control group, the expression level of lncRNA UCA1 was significantly elevated in patients with AML (P < 0.001); The proportion of patients with hemoglobin lower than 90 g/L in lncRNA UCA1 high expression group was significantly higher than that in lncRNA UCA1 low expression group (P =0.004); The expression level of lncRNA UCA1 was higher in M1, M2, and M4 subtypes, while it was lower in M0 and M5 subtypes, and the difference was statistically significant (P =0.009). There were no significant difference in sex, age, white blood cell (WBC) count, platelet (PLT) count, bone marrow blasts , chemotherapy regimen and efficacy, karyotype, gene mutation, and prognostic risk stratification between patients in UCA1 high expression group and those in UCA1 low expression group (all P > 0.05). The OS of patients with high expression of lncRNA UCA1 was significantly shorter than that of patients with low expression of lncRNA UCA1 (P =0.0229). CONCLUSION: The expression level of lncRNA UCA1 is significantly upregulated in AML patients. High expression of lncRNA UCA1 is associated with poor clinicopathological features and poor prognosis. Therefore, lncRNA UCA1 can be used as a prognostic indicator and a potential therapeutic target for AML patients.
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Leucemia Mieloide Aguda , RNA Longo não Codificante , Humanos , RNA Longo não Codificante/genética , Leucemia Mieloide Aguda/genética , Prognóstico , Medula Óssea/metabolismo , Masculino , Feminino , Relevância ClínicaRESUMO
An effective method was explored for the selective synthesis of sulfonamides and sulfenamides using sodium sulfinates and amines as starting materials. This method offers mild reaction conditions, a broad substrate scope, high efficiency, and readily accessible materials, making it suitable and an alternative strategy for the preparation of a variety of biologically or pharmaceutically active compounds.
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Objectives: Jian-Pi-Yin decoction (JPY), a prescription derived from the traditional Chinese medicine Shen-Ling-Bai-Zhu-San, has shown good clinical efficacy in the treatment of diarrhea caused by lactose intolerance. However, the mechanism of action of JPY in the treatment of diarrhea is not fully understood. Design: In this study, a rat diarrhea model was induced by high lactose feeding combined with standing on a small platform to investigate the ameliorating effect of JPY on hyper lactose-induced diarrhea in rats and its possible mechanism. Methods: The rat model of hyper lactose diarrhea was given high, medium, and low doses of JPY and the positive control drug Smida by gavage for 1 week. At the same time, NA+-H+ exchanger 3 (NHE3) inhibitor Tenapanor was administered orally for 3 weeks. Body weight, food intake, water intake, grip strength, and severity of diarrhea symptoms were measured in rats throughout the study. The serum, colon, and jejunum tissues of the model and drug-treated rats were collected for histopathological examination and analysis of relevant indicators. Results: JPY significantly alleviated the symptoms of fatigue, diet reduction and diarrhea in the model group. Glucagon-like peptide-1 (GLP-1) and cyclic adenosine monophosphate (cAMP) expression were also down-regulated after JPY treatment. JPY can significantly promote NHE3 in intestinal tissues of rats with diarrhea, and the mechanism is related to the decrease of GLP-1, inhibition of cAMP/PKA pathway activation, an increase of ubiquitin-specific protease 7 (USP7) and USP10 expression, and decrease of NHE3 ubiquitination and phosphorylation. Conclusion: JPY can reduce the expression of GLP-1, reduce the ubiquitination and phosphorylation of NHE3, regulate the expression of NHE3, at least partly improve ion transport in the intestinal epithelium, and improve the imbalance of electrolyte absorption, thus significantly reducing the diarrhea symptoms of rats with high lactose combined with small platform standing. Innovation: In this study, we explored the mechanism of intestinal GLP-1 activation of cAMP/PKA signaling pathway from multiple dimensions, and increased its expression by reducing phosphorylation and ubiquitination of NHE3, thereby treating chronic diarrhea associated with lactose intolerance.
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Learning representations with self-supervision for convolutional networks (CNN) has been validated to be effective for vision tasks. As an alternative to CNN, vision transformers (ViT) have strong representation ability with spatial self-attention and channel-level feedforward networks. Recent works reveal that self-supervised learning helps unleash the great potential of ViT. Still, most works follow self-supervised strategies designed for CNN, e.g., instance-level discrimination of samples, but they ignore the properties of ViT. We observe that relational modeling on spatial and channel dimensions distinguishes ViT from other networks. To enforce this property, we explore the feature SElf-RElation (SERE) for training self-supervised ViT. Specifically, instead of conducting self-supervised learning solely on feature embeddings from multiple views, we utilize the feature self-relations, i.e., spatial/channel self-relations, for self-supervised learning. Self-relation based learning further enhances the relation modeling ability of ViT, resulting in stronger representations that stably improve performance on multiple downstream tasks.
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Most hematological tumors have high-grade malignancy and low cure rate, requiring new molecular markers for detection and evaluation. Circular RNAs (circRNAs) are a class of non-coding RNAs with covalently closed-loop structures, which participate in gene transcription and translation by binding to microRNAs and proteins. In recent years, with the deepening research on circRNAs, circRNAs have been found to play an important role in hematological malignancies. In this review, the latest research progress on the function and molecular mechanism of circRNAs in hematological malignancies was systematically summarized, and it was found that circRNAs may be potential new biomarkers and therapeutic targets in hematological malignancies.
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Neoplasias Hematológicas , MicroRNAs , Neoplasias , Humanos , RNA Circular , MicroRNAs/genética , Neoplasias Hematológicas/genética , BiomarcadoresRESUMO
Surgical smoke is a byproduct of aerosols containing several components produced by energy equipment. The characteristics of surgical smoke components produced by different types of tissues or using different kinds of energy devices vary. For example, the average diameter of smoke particles produced by electrocautery is smaller, and the possibility of viable cells and pathogens in surgical smoke produced by an ultrasonic knife is higher. According to the characteristics of its composition, surgical smoke may be an important risk factor affecting the health and safety of operating room staff and patients. The use of surgical masks, suction devices and portable smoke evacuation systems can reduce this risk to some extent. However, most operating room staff members do not implement corresponding measures to protect themselves. In this paper, the characteristics of surgical smoke and the research progress in protective measures are briefly reviewed.
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Exposição Ocupacional , Salas Cirúrgicas , Humanos , Fumaça/efeitos adversos , Exposição Ocupacional/efeitos adversosRESUMO
Temporal/spatial receptive fields of models play an important role in sequential/spatial tasks. Large receptive fields facilitate long-term relations, while small receptive fields help to capture the local details. Existing methods construct models with hand-designed receptive fields in layers. Can we effectively search for receptive field combinations to replace hand-designed patterns? To answer this question, we propose to find better receptive field combinations through a global-to-local search scheme. Our search scheme exploits both global search to find the coarse combinations and local search to get the refined receptive field combinations further. The global search finds possible coarse combinations other than human-designed patterns. On top of the global search, we propose an expectation-guided iterative local search scheme to refine combinations effectively. Our RF-Next models, plugging receptive field search to various models, boost the performance on many tasks, e.g., temporal action segmentation, object detection, instance segmentation, and speech synthesis. The source code is publicly available on http://mmcheng.net/rfnext.
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Empowered by large datasets, e.g., ImageNet and MS COCO, unsupervised learning on large-scale data has enabled significant advances for classification tasks. However, whether the large-scale unsupervised semantic segmentation can be achieved remains unknown. There are two major challenges: i) we need a large-scale benchmark for assessing algorithms; ii) we need to develop methods to simultaneously learn category and shape representation in an unsupervised manner. In this work, we propose a new problem of large-scale unsupervised semantic segmentation (LUSS) with a newly created benchmark dataset to help the research progress. Building on the ImageNet dataset, we propose the ImageNet-S dataset with 1.2 million training images and 50k high-quality semantic segmentation annotations for evaluation. Our benchmark has a high data diversity and a clear task objective. We also present a simple yet effective method that works surprisingly well for LUSS. In addition, we benchmark related un/weakly/fully supervised methods accordingly, identifying the challenges and possible directions of LUSS. The benchmark and source code is publicly available at https://github.com/LUSSeg.
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BACKGROUND: The epidemiology on the human papillomavirus (HPV) among females in Southern China is not well-established. Baseline data on the prevalence of HPV infection in China prior to mass prophylactic HPV vaccination would be useful. Thus, this study aims to determine the type-specific HPV prevalence and distribution among females from Southern China prior to mass HPV vaccination. METHODS: A retrospective cross-sectional study employing 214,715 women attending ChenZhou NO.1 People's Hospital for cervical screening during 2012-2018 was conducted prior to widespread HPV vaccination. HPV genotype was detected using nucleic acid molecular diversion hybridization tests. The overall prevalence, age-specific prevalence, type distribution, and annual trend were analyzed. RESULTS: The overall HPV prevalence was 18.71% (95% confidence interval [CI], 18.55-18.88%) among Southern China females. During 2012-2018, the prevalence of HPV infection showed a downward tendency, from 21.63% (95% CI, 21.07-22.20%) in 2012 to 18.75% (95% CI, 18.35-19.16%) in 2018. Age-specific HPV distribution displayed a peak at young women aged less than 21 years (33.11, 95% CI, 31.13-35.15%), 20.07% (95% CI, 19.70-20.44%) among women aged 21-30 years, 17.29% (95% CI, 17.01-17.57%) among women aged 31-40 years, 17.23% (95% CI, 16.95-17.51%) among women aged 41-50 years, 21.65% (95% CI, 21.11-22.20%) among women aged 51-60 years, and 25.95% (95% CI, 24.86-27.07%) among women aged over 60 years. Of the 21 subtypes identified, the top three prevalent high-risk HPV (HR-HPV) genotypes were HPV52 (5.12%; 95% CI, 21.11-22.20%), - 16 (2.96%; 95% CI, 2.89-3.03%), and - 58 (2.51%; 95% CI, 2.44-2.58%); the predominant low-risk HPV (LR-HPV) genotypes were HPV81 (1.86%; 95%CI, 1.80-1.92%) and - 6 (0.69%; 95% CI, 0.66-0.73%) respectively. Incidence of HR-HPV only, LR-HPV only and mixed LR- and HR-HPV were 15.17, 2.07 and 1.47% respectively. Besides, single HPV infection accounted for 77.30% of all positive cases in this study. CONCLUSIONS: This study highlights 1) a high prevalence of HPV infection among females with a decreasing tendency towards 2012-2018, especially for young women under the age of 21 prior to mass HPV vaccination; 2) HPV52, - 16 and - 58 were the predominant HPV genotypes, suggesting potential use of HPV vaccine covering these HPV genotypes in Southern China.
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Alphapapillomavirus/genética , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Adolescente , Adulto , China/epidemiologia , Estudos Transversais , Feminino , Genoma Viral , Humanos , Vacinação em Massa , Pessoa de Meia-Idade , Vacinas contra Papillomavirus/administração & dosagem , Prevalência , Estudos Retrospectivos , Adulto JovemRESUMO
Periphytic algae are often used as an indicator to evaluate water quality. Here, the community structure of periphytic algae and its relationship with environment factors were analyzed in the main stream of the Songhua River during the summers of 2014 to 2019. The status and trends in ecological water quality were also evaluated based on bioassessments. Phytoplankton species belonging to 4 phyla and 58 genera were recorded, including 28 Bacillariophyta genera, 17 Chlorophyta genera, 10 Cyanophyta genera, and 3 Euglenophyta genera; Bacillariophyta, Chlorophyta, and Cyanophyta accounted for 48.28%, 29.31%, and 17.24% of the community, respectively. Cell densities varied between 1.29×104 and 8.42×104 ind·cm-3, with an average of 4.35×104 ind·cm-3. The dominant genera were Cyclotella, Melosira, Asterionella, Cymbella, Synedra, Pinnularia, Navicula, and Scenedesmus. The physicochemical water quality showed notable changes during the past six-year monitoring period. Specifically, the dissolved oxygen content increased year on year; ammonia nitrogen, total phosphorus, and total nitrogen first increased and then decreased; and, overall, water quality significantly improved in 2019. Relationship between periphytic algae and environmental factors was further examined using redundancy analysis (RDA), which showed that time was the main factor driving the succession of algal community structure. Dissolved oxygen (DO), ammonia nitrogen (NH4+-N), total nitrogen (TN), total phosphorus (TP), five-day biochemical oxygen demand (BOD), and chemical oxygen demand (COD) were also important environmental variables affecting algal community structure.
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Diatomáceas , Rios , China , Monitoramento Ambiental , Nitrogênio/análise , Fósforo/análise , Fitoplâncton , Estações do Ano , Qualidade da ÁguaRESUMO
In this work, we present the formation of two open-ended hexagonal-prism tubular macrocycles by the [6 + 12] self-assembly of the symmetric â¼120° organic ligand donor with â¼90° Pt(II) acceptor in a 1:2 ratio. The assembled structures were characterized by multinuclear NMR (1H NMR, 31P{1H} NMR, and 1H-1H COSY NMR), electrospray ionization mass spectrometry (ESI-TOF-MS), traveling wave ion mobility-mass spectrometry (TWIM-MS), and transmission electron microscopy. Molecular modeling was further conducted to get insight into their structured characteristics. We also examined their photophysical properties.
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Constructing polycyclic aromatics-based, highly emissive fluorophores with good solubility and tunable aggregated structures and properties is of great importance for film fabrication, solution processing, and relevant functionality studies. Herein, we describe a general strategy to endow conventional organic fluorophores with enhanced solubility and modulated fluorescent properties via their incorporation into coordination-driven self-assembled metallacycles. A widely used fluorophore, pyrene, was decorated with two pyridyl groups to yield functionalized pyrene 4. Mixing 4 with three aromatic dicarboxylates with different lengths and a 90° Pt(II) metal acceptor in a 2:2:4 stoichiometric ratio resulted in the formation of three metallacycles, 1, 2, and 3. The metallacycles display good solubility in polar organic solvents, highly aggregation-dependent fluorescence, and size-dependent emissions at higher concentrations. Moreover, metallacycle 2-based, silica-gel-supported film as fabricated not only is more emissive than the ligand 4-based one but also displays much improved sensing properties for amines in the vapor state, as demonstrated by significantly increased response speed and decreased recovery time. The enhanced solubility, unique fluorescence behavior, and multi-factor modulation character show that coordination-driven self-assembly can be utilized for the development of new fluorophores through simple modification of conventional fluorophores. The fluorophores synthesized this way possess not only complex topological structures but also good modularity and tunability in fluorescence behavior, which are important for grafting multi-stage energy-transfer systems necessary for the development of high-performance sensing materials.
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Aminas/análise , Aminas/química , Pirenos/química , Espectrometria de Fluorescência/instrumentação , Modelos Moleculares , Conformação Molecular , Processos FotoquímicosRESUMO
The synthesis, characterization, and temperature-responsive properties of two fluorescent organoplatinum(II) metallacycles are reported. Metallacycles M1 and M2 were prepared via the coordination-driven self-assembly of a 120° triarylamine ligand L1 and a 120° diplatinum(II) acceptor Pt-1 or 180° diplatinum(II) acceptor Pt-2, respectively. M1 and M2 are hexagonal metallacycles, comprising of three or six freely rotating anthracene pendants on their periphery, respectively. In response to the temperature variation between -20 and 60 °C, the ligand displays irregular emission changes, whereas both metallacycles show reversible absorption and emission spectral changes in THF. The changes in their green emission intensity also exhibit a linear correlation with the temperature variation, with an average sensitivity of -0.67% and -0.77% per °C for M1 and M2, respectively. Furthermore, in coordinating solvents, such as DMF and CH3CN, M1 and M2 show different behaviors: in the lower temperature range, i.e., below 30 °C, their spectral changes are similar to those observed in THF; however, at a higher temperature the metallacycles were presumably destroyed by the solvents and displayed ratiometric fluorescent responses, including a cyan emission of the ligand L1.
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Complexos de Coordenação/química , Corantes Fluorescentes/química , Compostos Organoplatínicos/química , Complexos de Coordenação/síntese química , Fluorescência , Corantes Fluorescentes/síntese química , Ligantes , Modelos Químicos , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Teoria Quântica , Solventes/química , TemperaturaRESUMO
Two purified endopolysaccharides derived from cultured Phellinus sp., individually named SHIP-1 and 2, were structurally characterized, along with an evaluation of their in vivo influential immunomodulatory activity in a healthy mammalian model. The structure of SHIP-1 was mainly composed of â4)-α-d-Fucp-(1â, â3,6)-α-d-Araf-(1â and â2,4)-ß-d-Galp-(â, with four residuals of α-d-Manp-(1â and one α-d-Glcp-(1â as sidegroups, while the planar structure and the heteronuclear multiple-bond correlation of SHIP-2 were not able to be analyzed. Biochemical analysis in the healthy mice model demonstrated that SHIP-1 increased the concentrations of the detected cytokines in a dosage-dependent manner but not in a time-dependent way. SHIP-2 exerted a positive effect in a dose-dependent manner over time for interferon gamma (IFN-γ) and interleukin (IL)-2 cytokine production at elevated dosages of 200, or 350 mg kg-1 d-1, while IFN-alpha(α) and IL-4 production was observed only in a dosage-dependent manner even at high dosages. Thus, SHIP-1 and 2 significantly improved the immune response through the intragastric administration of the tested high dosages by increasing the production of cytokines in the healthy mice, and these polysaccharides could possibly be used as an immunopotentiator in health foods or dietary supplements.
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Basidiomycota/química , Fatores Imunológicos/administração & dosagem , Fatores Imunológicos/química , Polissacarídeos/administração & dosagem , Polissacarídeos/química , Animais , Feminino , Interferon gama/genética , Interferon gama/imunologia , Masculino , Camundongos , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/genética , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/imunologiaRESUMO
Toxoplasma gondii has been suggested as an important opportunistic pathogen in immunocompromised patients. We conducted a global meta-analysis to assess the prevalence and odds ratios (ORs) of T. gondii infection in immunocompromised individuals. Electronic databases were reviewed for T. gondii infection in HIV/AIDS patients, cancer patients, and transplant recipients, and meta-analyses were conducted to calculate overall estimated prevalence and ORs using random or fixed-effects models. Totally, 72 eligible studies were included. The estimated pooled prevalence of T. gondii infection in immunocompromised patients and the control was 35.9 and 24.7% (p < 0.001), with an OR of 2.24, i.e., 42.1 and 32.0% for HIV/AIDS patients and the control (p < 0.05), 26.0 and 12.1% for cancer patients and the control (p < 0.001), and 42.1 and 34.5% for transplant recipients and the control (p > 0.05), whose estimated pooled ORs were 1.92 (95% CI, 1.44-2.55), 2.89 (95% CI, 2.36-3.55), and 1.51 (95% CI, 1.16-1.95), respectively. This study is the first to demonstrate that the immunocompromised patients are associated with higher odds of T. gondii infection, and appropriate prevention and control measures are highly recommended for these susceptible populations.
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BACKGROUND: Worldwide, 30% of the world's population have antibodies to the intracellular protozoan parasite Toxoplasma gondii and about 36·7 million people are infected with HIV, but little is known about the prevalence of co-infection with T gondii and HIV. We aimed to characterise the epidemiology and burden of T gondii co-infection in people with HIV infection. METHODS: In this systematic review and meta-analysis, we searched PubMed, Embase, Google Scholar, ScienceDirect, Chinese Web of Knowledge, Wanfang, and Chongqing VIP databases for studies reporting T gondii infection in HIV-infected people from inception to Feb 29, 2016. Studies were included if they investigated people with HIV infection and presented data that allowed us to establish the prevalence of T gondii infection. We excluded reviews, repeated studies, or animal studies, as well as studies that provided the final results without raw data, had a sample size less than 30 people, had unclear diagnostic methods of T gondii infection, or that included populations with increased risk of T gondii infection. We extracted the numbers of patients with HIV infection and T gondii co-infection from the identified studies. We estimated pooled prevalence of T gondii infection in HIV-infected people by a random-effects model, and evaluated its overall infection burden worldwide. FINDINGS: Our search identified 7843 records and after removal of duplicates and initial screening, we reviewed 312 studies in full. Of these articles, 238 were excluded, leaving 74 studies that included 25â989 HIV-infected people from 34 countries. Of these people, 7326 had T gondii co-infection and we estimated the pooled worldwide prevalence of T gondii infection to be 35·8% (95% CI 30·8-40·7). 2353 of 8837 of people in Asia and the Pacific had co-infection with T gondii and HIV (prevalence 25·1%, 95% CI 19·0-31·2), and prevalence was low in this region compared with that in sub-Saharan Africa (44·9%, 32·3-57·5, 2129/5686; odds ratio [OR] 0·61), Latin America and the Caribbean (49·1%, 27·9-70·4, 510/980; OR 0·33), and North Africa and the Middle East (60·7%, 24·1-97·3, 245/439; OR 0·29). 1561 of 3780 people in low-income countries had co-infection (54·7%, 95% CI 35·8-73·5), which was higher than in middle-income countries (34·2%, 27·4-40·9, 3632/11â540; OR 1·53) and high-income countries (26·3%, 20·4-32·2, 2133/10â669; OR 2·82). Worldwide, we calculated that there were roughly 13â138â600 (95% CI 11â303â600-14â936â900) cases of T gondii co-infection in HIV-infected people, with 87·1% in sub-Saharan Africa (11â449â500 cases, 95% CI 8â236â500-14â662â500). INTERPRETATION: Our findings suggest that people with HIV infection have a very high burden of T gondii infection, especially in sub-Saharan Africa, and emphasise the importance of routine surveillance for T gondii infection in all HIV-infected people. FUNDING: National Natural Science Foundation and the Special Fund for Agro-scientific Research in the Public Interest in China.
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Coinfecção/epidemiologia , Efeitos Psicossociais da Doença , Infecções por HIV/complicações , Toxoplasmose/complicações , Toxoplasmose/epidemiologia , Adolescente , África Subsaariana/epidemiologia , Região do Caribe/epidemiologia , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , Humanos , América Latina/epidemiologia , Prevalência , Toxoplasma/isolamento & purificação , Toxoplasmose/parasitologiaRESUMO
Using a series of tritopic 2,2':6',2â³-terpyridine (tpy) ligands constructed on adamantane, three discrete 3D metallo-supramolecular architectures were assembled, i.e., trigonal bipyramidal, tetrahedron, and cube. The self-assembly used tritopic ligands as corner directing units and metal ions as glue units at the edge. The angles of the linkers between adamantane and tpy head play a critical role in guiding the assembled structures, which have the general formula of M3nL2n, where M denotes metal ion and L denotes ligand. All complexes were fully characterized by (1)H, (13)C NMR, diffusion-ordered NMR spectroscopy, ESI-MS, and traveling-wave ion mobility-mass spectrometry. The binary mixtures of LA and LC or LB and LC underwent a self-sorting process that led to the self-assembly of discrete 3D structures. The self-sorting behavior is solely based on the angles precoded within the arm of tritopic ligands. Moreover, kinetic study of preassembled cube and tetrahedron demonstrated a slow ligand exchange process toward a statistical mixture of hetero tetrahedrons with LA and LB.
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Adamantano/química , Compostos Organometálicos/química , Compostos Organometálicos/síntese química , Piridinas/química , Piridinas/síntese química , Ligantes , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Processos Fotoquímicos , Espectrometria de Massas por Ionização por Electrospray , Propriedades de SuperfícieRESUMO
A new family of discrete hexakis-pillar[5]arene metallacycles with different sizes have been successfully prepared via coordination-driven self-assembly, which presented very few successful examples of preparation of discrete multiple pillar[n]arene derivatives. These newly designed hexakis-pillar[5]arene metallacycles were well characterized with one-dimensional (1-D) multinuclear NMR ((1)H and (31) P NMR), two-dimensional (2-D) (1)H-(1)H COSY and NOESY, ESI-TOF-MS, elemental analysis, and PM6 semiempirical molecular orbital methods. Furthermore, the host-guest complexation of such hexakis-pillar[5]arene hosts with a series of different neutral ditopic guests G1-6 were well investigated. Through host-guest interactions of hexakis-pillar[5]arene metallacycles H2 or H3 with the neutral dinitrile guest G5, the cross-linked supramolecular polymers H2â(G5)3 or H3â(G5)3 were successfully constructed at the high-concentration region, respectively. Interestingly, these cross-linked supramolecular polymers transformed into the stable supramolecular gels upon increasing the concentrations to a relatively high level. More importantly, by taking advantage of the dynamic nature of metal-ligand bonds and host-guest interactions, the reversible multiple stimuli-responsive gel-sol phase transitions of such polymer gels were successfully realized under different stimuli, such as temperature, halide, and competitive guest, etc. The mechanism of such multiple stimuli-responsive processes was well illustrated by in situ multinuclear NMR investigation. This research not only provides a highly efficient approach to the preparation of discrete multiple pillar[n]arene derivatives but also presents a new family of multiple stimuli-responsive "smart" soft matters.
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Reagentes de Ligações Cruzadas/química , Compostos Organoplatínicos/química , Polímeros/química , Compostos de Amônio Quaternário/química , Calixarenos , Reagentes de Ligações Cruzadas/síntese química , Géis/síntese química , Géis/química , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Polímeros/síntese químicaRESUMO
A series of new triarylamine-based platinum-acetylide complexes (WYs) have been designed and synthesized as new sensitizers for applications in dye-sensitized solar cells (DSSCs). With the aim of investigating the effect of a rigidifying donor structure on the photoelectrical parameters of the corresponding DSSCs, two new sensitizers, WY1 and WY2, with rigid and coplanar fluorene units as an electron donor, were prepared. Moreover, two sensitizers that contained triphenylamine units as an electron donor, WY3 and WY4, were also synthesized for comparison. The photo- and electrochemical properties of all of these new complexes have been extensively explored. We found that the dimethyl-fluorene unit exhibited a stronger electron-donating ability and better photovoltaic performance compared to the triphenylamine unit, owing to its rigidifying structure, which restricted the rotation of σ bonds, thus increasing the conjugation efficiency. Furthermore, WY2, which contained a dimethyl-fluorene unit as an electron donor and bithiophene as a π bridge, showed a relatively high open-circuit voltage (V(oc)) of 640 mV and a PCE of 4.09%. This work has not only expanded the choice of platinum-acetylide sensitizers, but also demonstrates the advantages of restricted rotation of donor σ bonds for improved behavior of the corresponding DSSCs.
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Through a stepwise fragment coupling approach, a family of novel platinum-acetylide metallocycles with well-defined shape and size were successfully constructed. Their aggregation behavior was investigated.