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Flexible metal-organic frameworks (FMOFs) exhibit reversible structural transitions ("breathing" behaviors), which can regulate the proton transport passageway effectively. This property offers remarkable advantages for improving the proton conductivity. Our objective of this work is to design a single-variable flexibility synergistic strategy for the fabrication of FMOFs with high conductivity. Herein, four two-dimensional FMOFs, {[Co(4-bpdb)(R-ip)]·xsolvents}n (x = rich, 1-4), have been successfully designed and assembled (4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and R-ip = MeO/EtO/n-PrO/n-BuO-isophthalate). Upon the release and/or absorption of different solvent molecules, they display reversible breathing behaviors, thereby resulting in the formation of the partial and complete solvent-free compounds {[Co(4-bpdb)(R-ip)]·ysolvents}n (y = free or poor, 1A-4A). This breathing behavior involves the synergistic self-adaption of the dynamic torsion of alkoxy groups and reversible structural transformation, leading to remarkable changes in cell parameters and void space, as evidenced by single-crystal X-ray diffraction, powder X-ray diffraction, and N2 and CO2 adsorption analyses. At 363 K and 98% relative humidity, 2A exhibits the best proton conductivity among the FMOFs. Its conductivity reaches 4.08 × 10-2 S cm-1 and is one of the highest conductivities shown by reported unmodified MOF-based proton conductors.
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Metal-organic frameworks (MOFs) have shown promising potential as proton-conducting materials due to their tunable structures and high porosity. In this study, two novel MOFs had been successfully synthesized, one containing sulfate groups (MOF-1; [Zn4(TIPE)2(SO4)4(H2O)]·5H2O) and the other containing sulfonate groups (MOF-2; [Zn2(TIPE)(5-sip)(NO3)0.66]·0.34NO3·17.5H2O) (TIPE = 1,1,2,2-tetrakis(4-(1H-imidazole-1-yl)phenyl)ethene, H35-sip = 5-sulfoisophthalicacid), and the effect of the two groups on the proton conductivity of Zn-based MOFs had been investigated and compared for the first time. The proton conductivity of these MOFs was systematically measured at different temperatures and humidity conditions. Remarkably, the results revealed significant differences in proton conductivity between the two sets of MOFs. At 90 °C and 98% RH, MOF-1 and MOF-2 achieved optimal proton conductivity of 4.48 × 10-3 and 5.69 × 10-2 S·cm-1, respectively. This was due to the structural differences arising from the presence of different functional groups, which subsequently affected the porosity and hydrophilicity, thereby influencing the proton conductivity. Overall, this comparative study revealed the influence of sulfate and sulfonate groups on the proton conductivity of Zn-based MOFs. This research provided a feasible idea for the development of advanced MOF materials with enhanced proton conductivity and opened up new possibilities for their application in proton devices.
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In this work, a "fish cage" material for trapping Pb(II) ions has been successfully obtained, which is a novel clathrate functionalized metal-oganic framework (Cage-MOF) by introducing free adsorption sites (SO42-). The three-dimensional (3D) cage structure of Cage-MOF gives it a larger contact area and can capture "swimming fish" (Pb(II)) like a "fishing cage" in a water solution. This is the first high-efficiency adsorption material obtained by introducing free coordination groups. Cage-MOF not only has excellent water stability but also improves the selectivity and affinity for Pb(II) ions in water because of the presence of sulfate adsorption sites, and its adsorption capacity is as high as 806 mg/g. This work shows a novel and effective idea for the synthesis of water restoration materials.
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The modification of metal-organic framework (MOF) materials to facilitate their practical applications is an extremely challenging and meaningful topic. In this work, two stepwise modification strategies for MOFs were conducted. First, we have demonstrated a single-crystal-to-single-crystal (SCSC) transformation from a microporous three-dimensional (3D) MOF to a two-dimensional (2D) coordination polymer (CP). The centrosymmetric [Cd(3-bpdb)(MeO-ip)]n (1) transforms into a chiral [Cd2(3-bpdb)(MeO-ip)2(CH3OH)2]n (2), which is triggered by the reaction time with methanol that acts as a structure-directing agent. The conversion relationship of 1 to 2 at different reaction times was studied in detail. Density functional theory (DFT) calculations clearly state that the irreversible formation of 2 is thermodynamically favorable. Intriguingly, 2 exhibits good proton conduction of 1.34 × 10-3 S cm-1 under 363 K and 98% relative humidity (RH) due to unique H-bond network characteristics. To the best of our knowledge, there are very few cases of 3D to 2D SCSC transformation stimulated by reaction time. The results have important implications for understanding the SCSC transformation mechanism and synthetic chemistry. On the other hand, the lanthanide3+-functionalized hybrids (Ln3+-MOF), Ln3+@1, were continuously prepared by incorporating luminescent Ln3+ ions into the structure of 1 through encapsulating post-synthesis modification (PSM). Tb3+@1 exhibits double emission in water and shows visual ratiometric fluorescence behavior for sensing glutamic acid (Glu), tryptophan (Trp), and Al3+, which is more reliable and accurate than single emission. Our work may not only provide new insights into the multiple modification of MOF materials but also promote the practical application of such materials.
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There is an increasing interest in non-pharmacological treatments for children with attention-deficit/hyperactivity disorder (AD/HD), especially digital techniques that can be remotely delivered, such as neurofeedback (NFT) and computerized cognitive training (CCT). In this study, a randomized controlled design was used to compare training outcomes between remotely delivered NFT, CCT, and combined NFT/CCT training approaches. A total of 121 children with AD/HD were randomly assigned to the NFT, CCT, or NFT/CCT training groups, with 80 children completing the training program. Pre- and post-training symptoms (primary outcome), executive and daily functions were measured using questionnaires as well as resting EEG during eyes-closed (EC) and eyes-open (EO) conditions. After 3 months of training, the inattentive and hyperactive/impulsive symptoms, inhibition, working memory, learning and life skills of the three groups of children were significantly improved. The objective EEG activity showed a consistent increase in the relative alpha power in the EO condition among the three training groups. Training differences were not observed between groups. There was a positive correlation between pre-training EO relative alpha power and symptom improvement scores of inattention and hyperactivity/impulsivity, as well as a negative correlation between pre-training inattention scores and change in EO relative alpha. This study verified the training effects of NFT, CCT, and combined NFT/CCT training in children with AD/HD and revealed an objective therapeutic role for individual relative alpha activity. The verified feasibility and effectiveness of home-based digital training support promotion and application of digital remote training.
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Trastorno por Déficit de Atención con Hiperactividad , Neurorretroalimentación , Humanos , Niño , Neurorretroalimentación/métodos , Trastorno por Déficit de Atención con Hiperactividad/psicología , Aprendizaje , Cognición , Proyectos de Investigación , ElectroencefalografíaRESUMEN
Invited for the cover of this issue are the groups of Lin Du and Qi-Hua Zhao at Yunnan University. The image depicts astronauts as protons moving along the hydrogen-bond network in the channel of Eu-ETTB/Gd-ETTB. Read the full text of the article at 10.1002/chem.202202154.
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In this work, the two example rare earth-based metal-organic frameworks (LaIII -based MOFs), Eu-ETTB and Gd-ETTB, were obtained by self-assembly. Both materials showed extremely high proton conductivity, with the proton conductivity of Eu-ETTB being 1.53×10-2 â S cm-1 at 98 % relative humidity (RH) and 85 °C and that of Gd-ETTB being 2.63×10-2 â S cm-1 at 98 % RH and 75 °C. This was almost the best performance observed for three-dimensional porous MOFs without post-synthetic modification and was based on milder conditions than for most materials. Furthermore, cycle test experiments and continuous work tests showed that both materials had excellent performance both in terms of stability and durability. Water vapor adsorption experiments showed that a large number of water molecules are adsorbed the hydrogen-bond network's being rebuilt by the adsorbed water molecules in the pore channel and thus optimizing the channels for proton transfer explained the MOF's high performance.
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The recognition and adsorption of silver ions (Ag+) from industrial wastewater are necessary but still challenging. Herein, we constructed four Zn(II)-based coordination polymers (CPs), namely, [Zn(btap)2(NO3)2]n (1), [Zn(btap)(SO4)(H2O)3]n (2), {[Zn(btap)2(H2O)2]·(ClO4)2}n (3), and [Zn(btap)Cl2]n (4), by using 3,5-bis(triazol-1-yl)pyridine (btap) with different anionic Zn(II) salts. The crystal structures of 1-4, varying from one-dimensional beaded (1) and zigzag chain (2) to two-dimensional sql (3) and bex (4) typologies, were regulated by the coordination modes of btap and the counter-anions. The water stability, pH stability, thermostability, and luminescent properties of the CPs were investigated. The luminescence performances in a series of cations and anions were also explored. Considering the high density of chloride groups in the structure, 4 showed luminescence sensing for Ag+ [KSV = 9188.45 M-1 and a limit of detection (LOD) of 4.9 µM], as well as an excellent ability for Ag+ adsorption in aqueous solution (maximum adsorption capacity, 653.3 mg/g). Additionally, anti-interference experiments revealed that 4 had excellent recognition and adsorption capacities for Ag+ even when multiple ions coexisted. Moreover, XRD, EDS, and XPS analyses confirmed that the coordination of Ag+ with chloride groups in 4 resulted in excellent adsorption capacity and prevented ligand-to-ligand electron transfer, showing excellent detection ability. Suitable coordination sites were introduced to interact strongly with Ag+, along with detection and large adsorption capacity. Our strategy can effectively design and develop multifunctional CP-based materials, which are applicable in removal processes and environmental protection, by regulating anions in the self-assembly and introducing CP functional groups.
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Polímeros , Plata , Plata/química , Polímeros/química , Ligandos , Adsorción , Cloruros , Aniones/química , Agua/químicaRESUMEN
High-surface-area mesoporous CeO2 (hsmCeO2 ) was prepared by a facile organic-template-induced homogeneous precipitation process and showed excellent catalytic activity in imine synthesis in the absence of base from primary alcohols and amines in air atmosphere at low temperature. For comparison, ordinary CeO2 and hsmCeO2 after different thermal treatments were also investigated. XRD, N2 physisorption, UV-Raman, H2 temperature-programmed reduction, O2 temperature-programmed desorption, EPR spectroscopy, and X-ray photoelectron spectroscopy were used to unravel the structural and redox properties. The hsmCeO2 calcined at 400 °C shows the highest specific surface area (158â m2 g-1 ), the highest fraction of surface coordinatively unsaturated Ce3+ ions (18.2 %), and the highest concentration of reactive oxygen vacancies (2.4×1015 â spins g-1 ). In the model reaction of oxidative coupling of benzyl alcohol and aniline, such an exceptional redox property of the hsmCeO2 catalyst can boost benzylideneaniline formation (2.75 and 5.55â mmol g ceria - 1 h-1 based on >99 % yield at 60 and 80 °C, respectively) in air with no base additives. It can also work effectively at a temperature of 30 °C and in gram-scale synthesis. These are among the best results for all benchmark ceria catalysts in the literature. Moreover, the hsmCeO2 catalyst shows a wide scope towards primary alcohols and amines with good to excellent yield of imines. The influence of reaction parameters, the reusability of the catalyst, and the reaction mechanism were investigated.
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Using multifunctional organic ligands with multiple acidic groups (carboxylate and sulfonate groups) to synthesize metal-organic frameworks (MOFs) bearing effective H-bond networks is a promising strategy to obtain highly proton conductive materials. In this work, a highly stable two-dimensional MOF, [CuII5CuI2(µ3-OH)4(H2O)6(L)2(H2L)2]·3H2O (denoted as YCu161; H3L = 6-sulfonaphthalene-1,4-dicarboxylic acid) containing mixed-valence [CuII5CuI2(µ3-OH)4]8+ subunits, was successfully prepared. It exhibited excellent stability and temperature- and humidity-dependent proton conduction properties. Its optimal proton conductivity reached 1.84 × 10-3 S cm-1 at 90 °C and 98% relative humidity. On the basis of a crystal structure analysis, water vapor adsorption test results, and activation energy calculations, we deduced the proton conduction pathway and mechanism. Apparently, uncoordinated sulfonic and carboxyl groups and a network of abundant H-bonds inside the framework were responsible for the efficient proton transfer. Therefore, the strategy of selecting suitable bifunctional ligands to construct two-dimensional Cu-cluster-based MOFs with excellent proton conductivity is feasible.
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A new schiff base cobalt(III) complex [N,N'-bis(2'-hydroxyphenylacetone)-o-ethanediamine] cobalt(III) (M3) has been synthesized and characterized by single X-ray crystallography. The cytotoxicity of complex M3 was evaluated against HeLa, LoVo, A549, A549/cis cancer cell lines, and the normal cell lines LO2 by MTT assays. The IC50 is in the range of 6.27-22.68 µM, which is somewhat lower than cisplatin on the basis of platinum molar concentration. Furthermore, anticancer mechanistic studies showed that the complex M3 inhibited cell proliferation by blocking DNA synthesis and then acted on nuclear division of HeLa cells over time. Moreover, western blot analysis indicated M3 dramatically decreased the target protein c-Myc and KLF5 expression levels, and activated many signaling pathways including ER stress, apoptosis, cell cycle and DNA damage in HeLa. M3 did not affect proteasomal activity.
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Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Cobalto/farmacología , Complejos de Coordinación/farmacología , Neoplasias del Cuello Uterino/tratamiento farmacológico , Antineoplásicos/síntesis química , Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Cobalto/química , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Humanos , Bases de Schiff/química , Bases de Schiff/farmacología , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patologíaRESUMEN
Three novel Zn-based coordination polymers (CPs), [Zn(MIPA)]n (1), {[Zn(MIPA)(4,4'-bipy)0.5(H2O)]·1.5H2O}n (2), and {[Zn(MIPA)(bpe)]·H2O}n (3) (MIPA = 4-methoxyisophthalic acid, 4,4'-bipy = 4,4'-bipyridine, bpe = (E)-1,2-di(pyridine-4-yl)ethane), were constructed by ligand 4-methoxyisophthalic acid under solvothermal conditions. Compound 1 features a beaded 2D-layer architecture, while compound 2 presents a 2-fold interpenetrating structure with a uninodal three-connected hcb topology. Compound 3 has a 3-fold interpenetrated four-connected dmp topology. Photoluminescence investigations of compound 2 were explored in detail, by which ions were detected, and it was observed to have the highest quenching efficiency toward Al3+ and S2- ions. The possible fluorescence quenching mechanisms of 2 toward Al3+ and S2- ions were also explored. To the best of our knowledge, this is the first potential dual-responsive luminescent probe based on a Zn(II) coordination polymer for detecting Al3+ and S2- ions via a luminescence quenching effect in ethanol.
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Aluminio/análisis , Polímeros/síntesis química , Sulfuros/análisis , Zinc/química , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Cristalografía por Rayos X , Fluorescencia , Iones , Estructura Molecular , Polímeros/químicaRESUMEN
A family of two-dimensional (2D) Zn-based metal-organic frameworks (MOFs) with exitonic emission have been successfully synthesized under hydrothermal conditions. When isophthalic acid ligands with different substitutions are introduced, the crystal structures and fluorescence properties are significantly changed. Hirshfeld surface calculation is used to study the nuances of diverse substitutions during the construction of all of the crystals. The solid fluorescence results indicate that there are obvious two-channel emissions, including intralayer excimers and interlayer trapped excitons, both in 1 and 2 with a double-layer structure and in 3 with a single-layer structure, mainly exhibiting intralayer emission. Furthermore, the fluorescence changes on morphology transformations are explored after mechanical exfoliation consisting of grinding and ultrasonicaation of MOFs 1-3. The regulation and control of crystal structure and morphology can suppress emission based on interlayer excitons, achieving adjustment of the overall emitting color. To the best of our knowledge, this is the first report of 2D bilayer MOFs with dual-channel emissions, which provides a new structural model for synthesizing new exciton materials.
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In this study we extend on behavioural evidence to examine the effect of time on EEG measures related to arousal and emotion/motivation in children with/without AD/HD. Thirty children with AD/HD and 30 age- and sex-matched controls participated. EEG was recorded during an eyes-closed resting condition and divided into three 2.5 min blocks after pre-processing. Time effects for absolute and relative alpha activity were found in healthy controls; these effects did not interact with AD/HD status. Interactions between time and AD/HD status were found for absolute theta, relative theta, and theta/beta ratio (TBR), with these EEG indices increasing over time in children with AD/HD. Moreover, IQ played a role in the interaction between time and AD/HD status. These results are consistent with predictions from both the optimal stimulation model and the delay aversion model, and suggest important methodological considerations for future EEG research in children with/without AD/HD.
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Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Electroencefalografía , Adolescente , Ritmo alfa , Nivel de Alerta , Trastorno por Déficit de Atención con Hiperactividad/psicología , Ritmo beta , Mapeo Encefálico , Niño , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Emociones , Femenino , Humanos , Pruebas de Inteligencia , Masculino , Motivación , Descanso , Ritmo TetaRESUMEN
Increased expression of sodium channel SCN3A, an embryonic-expressed gene, has been identified in epileptic tissues, which is believed to contribute to the development of epilepsy. However, the regulatory mechanism of SCN3A expression under epileptic condition is still unknown. Here we showed a high level of Scn3a mRNA expression in mouse embryonic hippocampus with gradually decreasing to a low level during the postnatal development and a methylation of a specific CpG site (-39C) in the Scn3a promoter was increased in hippocampus during postnatal development, corresponding to the downregulation of Scn3a expression. Furthermore, in vitro methylation and -39C>T mutation of the Scn3a promoter decreased the reporter gene expression, suggesting an important role of the -39C site in regulating gene expression. We then demonstrated that the sequence containing -39C was a MBD2-binding motif and the CpG methylation of the promoter region increased the capability of MBD2's binding to the motif. Knockdown of MBD2 in mouse N1E-115 cells led to the -39C methylation and the downregulation of Scn3a transcription by decreasing the Scn3a promoter activity. In the hippocampus of seizure mice, the expressions of Scn3a and Mbd2 were upregulated after 10-day KA treatment. At the same time point, the -39C site was demethylated and the capability of MBD2's binding to the Scn3a promoter motif was decreased. Taken together, these findings suggest that CpG methylation and MBD2 are involved in altering Scn3a expression during postnatal development and seizure condition.
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Proteínas de Unión al ADN/biosíntesis , Hipocampo/crecimiento & desarrollo , Canal de Sodio Activado por Voltaje NAV1.3/biosíntesis , Convulsiones/genética , Animales , Islas de CpG/genética , Metilación de ADN/genética , Proteínas de Unión al ADN/genética , Desarrollo Embrionario , Regulación del Desarrollo de la Expresión Génica , Hipocampo/patología , Humanos , Ratones , Canal de Sodio Activado por Voltaje NAV1.3/genética , ARN Mensajero/genética , Convulsiones/patología , Transcripción GenéticaRESUMEN
Mutations in the SCN1A gene-encoding voltage-gated sodium channel α-I subunit (Nav1.1) cause various spectrum of epilepsies including Dravet syndrome (DS), a severe and intractable form. A large number of SCN1A mutations identified from the DS patients lead to the loss of function or truncation of Nav1.1 that result in a haploinsufficiency effects, indicating that the exact expression level of SCN1A should be essential to maintain normal brain function. In this study, we have identified five variants c.*1025T>C, c.*1031A>T, c.*1739C>T, c.*1794C>T and c.*1961C>T in the SCN1A 3' UTR in the patients with DS. The c.*1025T>C, c.*1031A>T and c.*1794C>T are conserved among different species. Of all the five variants, only c.*1794C>T is a novel variant and alters the predicted secondary structure of the 3' UTR. We also show that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) only binds to the 3' UTR sequence containing the mutation allele 1794U but not the wild-type allele 1794C, indicating that the mutation allele forms a new GAPDH-binding site. Functional analyses show that the variant negatively regulates the reporter gene expression by affecting the mRNA stability that is mediated by GAPDH's binding, and this phenomenon could be reversed by shRNA-induced GAPDH knockdown. These findings suggest that GAPDH and the 3'-UTR variant are involved in regulating SCN1A expression at post-transcriptional level, which may provide an important clue for further investigating on the relationship between 3'-UTR variants and SCN1A-related diseases.
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Regiones no Traducidas 3' , Epilepsias Mioclónicas/genética , Gliceraldehído-3-Fosfato Deshidrogenasas/antagonistas & inhibidores , Mutación , Canal de Sodio Activado por Voltaje NAV1.1/genética , Alelos , Secuencia de Bases , Sitios de Unión , Niño , Epilepsias Mioclónicas/metabolismo , Epilepsias Mioclónicas/patología , Femenino , Regulación de la Expresión Génica , Gliceraldehído-3-Fosfato Deshidrogenasas/genética , Gliceraldehído-3-Fosfato Deshidrogenasas/metabolismo , Haploinsuficiencia , Humanos , Datos de Secuencia Molecular , Canal de Sodio Activado por Voltaje NAV1.1/metabolismo , Linaje , Unión Proteica , Estabilidad del ARN , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismoRESUMEN
Metal organic frameworks (MOFs) constructed with bismuth metal have not been widely reported, especially multifunctional Bi-MOFs. Therefore, developing multifunctional MOFs is of great significance due to the increasing requirements of materials. In this work, a 3D Bi-MOF (Bi-TCPE) with multifunctionality was successfully constructed, demonstrating high thermal stability, water stability, a porous structure, and strong blue fluorescence emission. We evaluated the properties of Bi-TCPE in detecting anions (S2-, Cr2O72-, and CrO42-) in aqueous solution, along with the rapid visual detection of H2S gas and proton conduction. In terms of anion detection, Bi-TCPE achieved the rapid detection of trace S2- in aqueous solutions, while the Ksv value was 1.224 × 104 M-1 with a limit of detection (LOD) value of 1.93 µM through titration experiments. Furthermore, Bi-TCPE could sensitively detect Cr2O72- and CrO42-, with Ksv values of 1.144 × 104 and 1.066 × 104 M-1, respectively, while LOD reached 2.07 and 2.18 µM. Subsequently, we conducted H2S gas detection experiments, and the results indicated that Bi-TCPE could selectively detect H2S gas at extremely low concentrations (2.08 ppm) and with a fast response time (<10 s). We also observed significant color changes under both UV light and sunlight. Therefore, we developed a H2S detection test paper for the rapid visual detection of H2S gas. Finally, we evaluated the proton conductivity of Bi-TCPE, and the experimental results showed that the proton conductivity of Bi-TCPE reached 4.77 × 10-2 S·cm-1 at 98% RH and 90 °C, achieving an excellent value for unmodified and encapsulated MOFs. In addition, Bi-TCPE showed high stability in proton conduction experiments (it remained stable after 21 consecutive days of testing and 12 cycles of testing), demonstrating relatively high application value. These results indicate that Bi-TCPE is a multifunctional MOF material with great application potential.
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Photo-responsive materials can convert light energy into mechanical energy, with great application potential in biomedicine, flexible electronic devices, and bionic systems. We combined reversible amide bonds, coordination site regulation, and coordination polymer (CP) self-assembly to synthesize two 1D photo-responsive CPs. Obvious photomechanical behavior was observed under UV irradiation. By combining the CPs with PVA, the mechanical stresses were amplified and macroscopic driving behavior was realized. In addition, two cyclobutane amide derivatives and a pair of cyclobutane carboxyl isomers were isolated through coordination bond destruction and amide bond hydrolysis. Therefore, photo-actuators and supramolecular synthesis in smart materials may serve as important clues.
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There is significant value in developing multifunctional drug delivery systems with high therapeutic efficiency for diagnosing and treating tumors. In this study, we synthesized the ATP-triggered and pH-sensitive material ZIF-90 using the liquid-phase diffusion method. This was done to load 10-hydroxycamptothecin (HCPT), and the FA-PEG-NH2 conjugate was synthesized through an amidation reaction. We further modified the HCPT@ZIF-90 nanocomposite by employing the Schiff base reaction to create the HCPT@ZIF-90-PEG-FA nanomaterial. Drug loading test results revealed a high HCPT drug loading of up to 22.3% by weight. In the drug release experiment, the cumulative drug release of HCPT@ZIF-90 nanomaterials in pH 5.4 and ATP solutions was the highest after 72 hours. The active targeted delivery of FA and the dual-responsive release of HCPT by ZIF-90 significantly enhanced the therapeutic effect of HCPT@ZIF-90-PEG-FA on human colon cancer cells (HCT116). In the cytotoxicity test, when 100 µg mL-1 of HCPT@ZIF-90-PEG-FA was incubated with cells, the cell survival rate was 16.61 ± 1.19%, significantly lower than that of the other experimental groups. This result indicates that HCPT@ZIF-90-PEG-FA exhibits excellent anti-tumor activity. Cell cycle experiments have shown that HCPT@ZIF-90-PEG-FA may inhibit the proliferation of cancer cells by blocking DNA synthesis and halting cell cycle progression. Cell uptake experiments showed that HCPT@ZIF-90-PEG-FA was mainly present in the cytoplasm of HCT1116 cells, indicating successful cellular entry of the drug to exert its therapeutic effect. In vivo experiments also demonstrated that HCPT@ZIF-90-PEG-FA nanomaterials can effectively eradicate HCT116 tumors. The utilization of the nano-drug carrier ZIF-90, along with the modification with PEG-FA, notably improved the therapeutic efficacy of HCPT. These results suggest that the system, with its active targeted delivery of FA and dual-responsive release of HCPT, could present a novel strategy for treating human colorectal cancer.
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Objective. Polycrystalline mercuric iodide photoconductive converters fabricated using particle-in-binder techniques (PIB HgI2) provide significantly more detected charge per x-ray interaction than from a-Se and CsI:Tl converters commonly used with active matrix flat-panel imagers (AMFPIs). This enhanced sensitivity makes PIB HgI2an interesting candidate for applications involving low x-ray exposures-since the relatively high levels of additive electronic noise exhibited by AMFPIs incorporating a-Se and CsI:Tl reduce detective quantum efficiency (DQE) performance under such conditions. A theoretical study is reported on an approach for addressing a major challenge impeding practical use of PIB HgI2converters-the high lag exhibited by the material (over 10%) which would lead to undesirable image artifacts in applications involving acquisition of consecutive images such as digital breast tomosynthesis.Approach. Charge transport modeling accounting for the trapping and release of holes (thought to be the primary contributor to lag) was used to examine signal properties, including lag, of pillar-supported Frisch grids embedded in the photoconductor for 100µm pitch AMFPI pixels. Performance was examined as a function of electrode voltage, grid pitch (center-to-center distance between neighboring grid wires) and the ratio of grid wire width to grid pitch.Main results. Optimum grid designs maximizing suppression of signal generated by hole transport, without significantly affecting the total signal due to electron and hole transport, were identified and MTF was determined. For the most favorable designs, additional modeling was used to determine DQE. The results indicate that, through judicious choice of grid design and operational conditions, first frame lag can be significantly reduced to below 1%-less than the low levels exhibited by a-Se. DQE performance is shown to be largely maintained as exposure decreases-which should help to maintain good image quality.Significance. Substantial reduction of lag in PIB HgI2converters via incorporation of Frisch grids has been demonstrated through modeling.