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1.
Adv Mater ; : e2403151, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38842511

RESUMEN

Water electrolysis to produce hydrogen (H2) using renewable energy is one of the most promising candidates for realizing carbon neutrality, but its reaction kinetics is hindered by sluggish anodic oxygen evolution reaction (OER). Ruthenium (Ru) in its high-valence state (oxide) provides one of the most active OER sites and is less costly, but thermodynamically unstable. The strong interaction between Ru nanoparticles (NPs) and nickel hydroxide (Ni(OH)2) is leveraged to directly form Ru-Ni(OH)2 on the surface of a porous nickel foam (NF) electrode via spontaneous galvanic replacement reaction. The formation of Ru─O─Ni bonds at the interface of the Ru NPs and Ni(OH)2 (Ru-Ni(OH)2) on the surface oxidized NF significantly enhance stability of the Ru-Ni(OH)2/NF electrode. In addition to OER, the catalyst is active enough for the hydrogen evolution reaction (HER). As a result, it is able to deliver overpotentials of 228 and 15 mV to reach 10 mA cm-2 for OER and HER, respectively. An industry-scale evaluation using Ru-Ni(OH)2/NF as both OER and HER electrodes demonstrates a high current density of 1500 mA cm-2 (OER: 410 mV; HER: 240 mV), surpassing commercial RuO2 (OER: 600 mV) and Pt/C based performance (HER: 265 mV).

2.
ACS Chem Neurosci ; 15(11): 2121-2131, 2024 06 05.
Artículo en Inglés | MEDLINE | ID: mdl-38775291

RESUMEN

Mapping brain activities is necessary for understanding brain physiology and discovering new treatments for neurological disorders. Such efforts have greatly benefited from the advancement in technologies for analyzing neural activity with improving temporal or spatial resolution. Here, we constructed a multielectrode array based brain activity mapping (BAM) system capable of stabilizing and orienting zebrafish larvae for recording electroencephalogram (EEG) like local field potential (LFP) signals and brain-wide calcium dynamics in awake zebrafish. Particularly, we designed a zebrafish trap chip that integrates with an eight-by-eight surface electrode array, so that brain electrophysiology can be noninvasively recorded in an agarose-free and anesthetic-free format with a high temporal resolution of 40 µs, matching the capability typically achieved by invasive LFP recording. Benefiting from the specially designed hybrid system, we can also conduct calcium imaging directly on immobilized awake larval zebrafish, which further supplies us with high spatial resolution brain-wide activity data. All of these innovations reconcile the limitations of sole LFP recording or calcium imaging, emphasizing a synergy of combining electrical and optical modalities within one unified device for activity mapping across a whole vertebrate brain with both improved spatial and temporal resolutions. The compatibility with in vivo drug treatment further makes it suitable for pharmacology studies based on multimodal measurement of brain-wide physiology.


Asunto(s)
Encéfalo , Electroencefalografía , Pez Cebra , Animales , Encéfalo/efectos de los fármacos , Encéfalo/fisiología , Electroencefalografía/métodos , Mapeo Encefálico/métodos , Calcio/metabolismo , Larva , Imagen Óptica/métodos
3.
Dalton Trans ; 53(24): 10189-10200, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38819397

RESUMEN

The accumulation of tetracycline hydrochloride (TCH) threatens human health because of its potential biological toxicity. Carbon -based materials with easy isolation and excellent performance that can activate peroxymonosulfate (PMS) to generate reactive oxygen species for TCH degradation are essential, but the development of such materials remains a significant challenge. In this study, based on the idea of treating waste, tricobalt tetraoxide loaded P-doped biochar (Co NP-PBC) was synthesised to activate PMS for the degradation of TCH. Possible degradation pathways and intermediate products of TCH were identified using High performance liquid chromatography tandem mass spectrometry (HPLC-MS) detection and density functional theory analysis. Toxicity analysis software was used to predict the toxicity of the intermediate products. Compared to catalysts loaded with Fe and Mn and other Co-based catalysts, Co NP-PBC exhibited an optimal performance (with a kinetic constant of 0.157 min-1 for TCH degradation), and over 99.0% of TCH can be degraded within 20 min. This mechanism demonstrates that the non-free radical oxidation of 1O2 plays a major role in the degradation of TCH. This study provides insights into the purification of wastewater using BC-based catalysts.


Asunto(s)
Carbón Orgánico , Cobalto , Peróxidos , Fósforo , Tetraciclina , Tetraciclina/química , Cobalto/química , Peróxidos/química , Fósforo/química , Carbón Orgánico/química , Nanopartículas del Metal/química , Contaminantes Químicos del Agua/química , Teoría Funcional de la Densidad
4.
J Am Chem Soc ; 146(15): 10953-10962, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38565222

RESUMEN

We report light gating in synthetic one-dimensional nanochannels of stable crystalline porous covalent organic frameworks. The frameworks consist of 2D hexagonal skeletons that are extended over the x-y plane and stacked along the z-direction to create dense yet aligned 1D mesoporous channels. The pores are designed to be photoadaptable by covalently integrating tetrafluoro-substituted azobenzene units onto edges, which protrude from walls and offer light-gating machinery confined in the channels. The implanted tetrafluoroazobenzene units are thermally stable yet highly sensitive to visible light to induce photoisomerization between the E and Z forms. Remarkably, photoisomerization induces drastic changes in intrapore polarity as well as pore shape and size, which exert profound effects on the molecular adsorption of a broad spectrum of compounds, ranging from inorganic iodine to organic dyes, drugs, and enzymes. Unexpectedly, the systems respond rapidly to visible lights to gate the molecular release of drugs and enzymes. Photoadaptable covalent organic frameworks with reversibly convertible pores offer a platform for constructing light-gating porous materials and tailorable delivery systems, remotely controlled by visible lights.

5.
Int J Neurosci ; : 1-11, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38682651

RESUMEN

OBJECTIVE: Acute Stanford Type A aortic dissection (AAAD) is a critical condition in vascular surgery, and total aortic arch replacement surgery is the preferred method to save patients' lives. In recent years, as clinical research has advanced, there has been a growing realization of the close association between poor postoperative outcomes in patients and neurological functional deficits. Neurological function monitoring is a medical technique used to evaluate and monitor the functional status of the nervous system. METHODS: This monitoring involves the assessment of various aspects of the nervous system, including but not limited to nerve conduction velocity, neuromuscular function, electroencephalographic activity, and sensory nerve transmission. Neurological function monitoring has broad clinical applications and can be used to diagnose and monitor many neurological disorders, helping physicians understand patients' neurological functional status and guide treatment plans. During the postoperative recovery process, neurological function monitoring can assist physicians in assessing the potential impact of surgery on the nervous system and monitor the recovery of patients' neurological function. RESULTS: Studies have shown that neurological function monitoring holds promise in predicting neurological functional prognosis and interventions for patients with aortic dissection. CONCLUSION: Therefore, the primary objective of this study is to evaluate the effectiveness and reliability of various intraoperative neurological monitoring techniques, neuroimaging examinations, and biomarkers in predicting and assessing postoperative neurological outcomes in patients undergoing AAAD surgery.

6.
Artículo en Inglés | MEDLINE | ID: mdl-38518162

RESUMEN

Objective: The objective of this study was to investigate the transition readiness of juvenile epilepsy patients during the transition period from childhood to adulthood and analyze the impact of patients' basic characteristics and self-management on their transition readiness. Methods: A total of 376 adolescent epileptic patients were selected as research objects from 3A general hospitals located in Chongqing, Guizhou, and Yunnan respectively, and a 3A children's specialist hospital in Chongqing, Jiangxi from May 2021 to February 2022. The readiness for transition was assessed using a transition readiness questionnaire, and patients' self-management skills were evaluated using the Self-Management Scale for Epilepsy Patients. Data analysis was conducted to determine the readiness for transition and examine the factors influencing it. Results: The mean overall transition readiness score in adolescent epilepsy patients was (56.60±12.51). Among the six dimensions, drug management, disease understanding, doctor-patient interaction, health responsibility, medical involvement, and resource utilization were ranked highest to lowest. The examination identified age, epilepsy duration, medication types, and primary caregivers as the primary factors influencing transition readiness in adolescent epilepsy patients (P < .001). Additionally, there was a favorable correlation between the total disease self-management score and transition readiness (r=0.487, P < .01), signifying the positive predictive impact of self-management skills on transition readiness. Conclusion: Adolescent epilepsy patients exhibited moderate readiness for the transition from childhood to adulthood. Older patients with longer disease duration and stronger self-management skills displayed a higher level of readiness. Targeted clinical interventions that prioritize self-management skills are essential for facilitating a smoother transition into adulthood for patients.

7.
Angew Chem Int Ed Engl ; 63(16): e202400009, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38415815

RESUMEN

Covalent organic frameworks are a novel class of crystalline porous polymers that enable molecular design of extended polygonal skeletons to attain well-defined porous structures. However, construction of a framework that allows remote control of pores remains a challenge. Here we report a strategy that merges covalent, noncovalent, and photo chemistries to design photoresponsive frameworks with reversibly and remotely controllable pores. We developed a topology-guided multicomponent polycondensation system that integrates protruded tetrafluoroazobenzene units as photoresponsive sites on pore walls at predesigned densities, so that a series of crystalline porous frameworks with the same backbone can be constructed to develop a broad spectrum of pores ranging from mesopores to micropores. Distinct from conventional azobenzene-based systems, the tetrafluoroazobenzene frameworks are highly sensitive to visible lights to undergo high-rate isomerization. The photoisomerization exerts profound effects on pore size, shape, number, and environment, as well as molecular uptake and release, rendering the system able to convert and switch pores reversibly and remotely with visible lights. Our results open a way to a novel class of smart porous materials with pore structures and functions that are convertible and manageable with visible lights.

8.
Sci Total Environ ; 912: 169371, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38104809

RESUMEN

The constraint of phosphorus (P) fixation on crop production in alkaline calcareous soils can be alleviated by applying bioinoculants. However, the impact of bacterial inoculants on this process remains inadequately understood. Here, a field study was conducted to investigate the effect of a high-concentration, cost-effective, and slow-release granular bacterial inoculant (GBI) on maize (Zea mays L.) plant growth. Additionally, we explored the effects of GBI on rhizosphere soil aggregate physicochemical properties, rhizosphere soil P fraction, and microbial communities within aggregates. The outcomes showed a considerable improvement in plant growth and P uptake upon application of the GBI. The application of GBI significantly enhanced the AP, phoD gene abundance, alkaline phosphatase activity, inorganic P fractions, and organic P fractions in large macroaggregates. Furthermore, GBI impacted soil aggregate fractionation, leading to substantial alterations in the composition of fungal and bacterial communities. Notably, key microbial taxa involved in P-cycling, such as Saccharimonadales and Mortierella, exhibited enrichment in the rhizosphere soil of plants treated with GBI. Overall, our study provides valuable insight into the impact of GBI application on microbial distributions and P fractions within aggregates of alkaline calcareous soils, crucial for fostering healthy root development and optimal crop growth potential. Subsequent research endeavors should delve into exploring the effects of diverse GBIs and specific aggregate types on P fraction and community composition across various soil profiles.


Asunto(s)
Inoculantes Agrícolas , Microbiota , Suelo/química , Zea mays , Rizosfera , Fósforo , Microbiología del Suelo
9.
Anesthesiology ; 140(4): 786-802, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38147625

RESUMEN

BACKGROUND: Analgesic tolerance due to long-term use of morphine remains a challenge for pain management. Morphine acts on µ-opioid receptors and downstream of the phosphatidylinositol 3-kinase signaling pathway to activate the mammalian target of rapamycin (mTOR) pathway. Rheb is an important regulator of growth and cell-cycle progression in the central nervous system owing to its critical role in the activation of mTOR. The hypothesis was that signaling via the GTP-binding protein Rheb in the dorsal horn of the spinal cord is involved in morphine-induced tolerance. METHODS: Male and female wild-type C57BL/6J mice or transgenic mice (6 to 8 weeks old) were injected intrathecally with saline or morphine twice daily at 12-h intervals for 5 consecutive days to establish a tolerance model. Analgesia was assessed 60 min later using the tail-flick assay. After 5 days, the spine was harvested for Western blot or immunofluorescence analysis. RESULTS: Chronic morphine administration resulted in the upregulation of spinal Rheb by 4.27 ± 0.195-fold (P = 0.0036, n = 6), in turn activating mTOR by targeting rapamycin complex 1 (mTORC1). Genetic overexpression of Rheb impaired morphine analgesia, resulting in a tail-flick latency of 4.65 ± 1.10 s (P < 0.0001, n = 7) in Rheb knock-in mice compared to 10 s in control mice (10 ± 0 s). Additionally, Rheb overexpression in spinal excitatory neurons led to mTORC1 signaling overactivation. Genetic knockout of Rheb or inhibition of mTORC1 signaling by rapamycin potentiated morphine-induced tolerance (maximum possible effect, 52.60 ± 9.56% in the morphine + rapamycin group vs. 16.60 ± 8.54% in the morphine group; P < 0.0001). Moreover, activation of endogenous adenosine 5'-monophosphate-activated protein kinase inhibited Rheb upregulation and retarded the development of morphine-dependent tolerance (maximum possible effect, 39.51 ± 7.40% in morphine + metformin group vs. 15.58 ± 5.79% in morphine group; P < 0.0001). CONCLUSIONS: This study suggests spinal Rheb as a key molecular factor for regulating mammalian target of rapamycin signaling.


Asunto(s)
Proteínas de Unión al GTP Monoméricas , Femenino , Masculino , Ratones , Animales , Proteínas de Unión al GTP Monoméricas/genética , Proteínas de Unión al GTP Monoméricas/metabolismo , Morfina/farmacología , Sirolimus/farmacología , Ratones Endogámicos C57BL , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Dolor , Mamíferos/metabolismo
10.
Appl Radiat Isot ; 201: 111024, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37725889

RESUMEN

The beam dynamics optimization study of Rhodotron electron accelerator for irradiation sterilization is introduced in this paper. The Rhodotron accelerator acceleration principle and the RF field distribution in the coaxial resonant cavity are described in detail. Beam dynamics in the Rhodotron accelerator are analyzed from both transverse and longitudinal directions. Beam dynamics of two kinds of Rhodotron electron accelerators with maximum beam energy of 10 MeV and 40 MeV were optimized based on multi-objective genetic algorithm. The key parameters of Rhodotron accelerators are determined, and the influence of some parameters on the overall acceleration effect is quantitatively analyzed. This paper provides some references for the research, manufacture, installation, and commissioning of this type of accelerator.

11.
Angew Chem Int Ed Engl ; 62(42): e202310941, 2023 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-37648674

RESUMEN

Engineering functional nucleic acids that are active under unusual conditions will not only reveal their hidden abilities but also lay the groundwork for pursuing them for unique applications. Although many DNAzymes have been derived to catalyze diverse chemical reactions in aqueous solutions, no prior study has been set up to purposely derive DNAzymes that require an organic solvent to function. Herein, we utilized in vitro selection to isolate RNA-cleaving DNAzymes from a random-sequence DNA pool that were "compelled" to accept 35 % dimethyl sulfoxide (DMSO) as a cosolvent, via counter selection in a purely aqueous solution followed by positive selection in the same solution containing 35 % DMSO. This experiment led to the discovery of a new DNAzyme that requires 35 % DMSO for its catalytic activity and exhibits drastically reduced activity without DMSO. This DNAzyme also requires divalent metal ions for catalysis, and its activity is enhanced by monovalent ions. A minimized, more efficient DNAzyme was also derived. This work demonstrates that highly functional, organic solvent-dependent DNAzymes can be isolated from random-sequence DNA libraries via forced in vitro selection, thus expanding the capability and potential utility of catalytic DNA.


Asunto(s)
ADN Catalítico , Solventes , Dimetilsulfóxido , ADN Catalítico/genética , Iones , ARN
12.
Angew Chem Int Ed Engl ; 62(37): e202307459, 2023 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-37488979

RESUMEN

Despite the enormous interest in Li metal as an ideal anode material, the uncontrollable Li dendrite growth and unstable solid electrolyte interphase have plagued its practical application. These limitations can be attributed to the sluggish and uneven Li+ migration towards Li metal surface. Here, we report olefin-linked covalent organic frameworks (COFs) with electronegative channels for facilitating selective Li+ transport. The triazine rings and fluorinated groups of the COFs are introduced as electron-rich sites capable of enhancing salt dissociation and guiding uniform Li+ flux within the channels, resulting in a high Li+ transference number (0.85) and high ionic conductivity (1.78 mS cm-1 ). The COFs are mixed with a polymeric binder to form mixed matrix membranes. These membranes enable reliable Li plating/stripping cyclability over 700 h in Li/Li symmetric cells and stable capacity retention in Li/LiFePO4 cells, demonstrating its potential as a viable cationic highway for accelerating Li+ conduction.

13.
Environ Sci Pollut Res Int ; 30(35): 84002-84010, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37353701

RESUMEN

Amphiphilic blue-fluorescence carbon dots (B-CDs) were synthesized via pyrolysis method with citric acid and oleamine as precursors. B-CDs are monodispersed in ethanol, toluene, and ultrapure water with the average particle sizes of 3.33 nm, 2.05 nm, and 4.12 nm, respectively. The maximum emission wavelength of the B-CDs excitation at 370 nm is located at 459 nm. The B-CDs have good optical properties with excellent photostability. The fluorescence quantum yield (QY) of the as-prepared CDs is as high as 30.17%. The fluorescence of B-CDs is quenched because of static quenching by oxytetracycline. A high selective and sensitive fluorescence probe for detecting oxytetracycline was constructed with a linear range of 1.52-27.60 µg/mL and the detection limit of 0.33 µg/mL. The B-CDs-based fluorescence probe can be applied to analyze oxytetracycline in milk; the recoveries and relative standard are satisfactory. Furthermore, the B-CDs were exploited for imaging of SH-SY5Y cells. The results demonstrate that as-synthesized CDs can serve as a cellular imaging reagent owing to remarkable bioimaging performance. This work provides a new strategy for the detection of oxytetracycline in food.


Asunto(s)
Neuroblastoma , Oxitetraciclina , Puntos Cuánticos , Humanos , Animales , Colorantes Fluorescentes , Carbono , Leche , Pirólisis , Espectrometría de Fluorescencia
14.
Math Biosci Eng ; 20(3): 5243-5267, 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36896544

RESUMEN

In this paper, we consider the quasilinear parabolic-elliptic-elliptic attraction-repulsion system $ \begin{equation} \nonumber \left\{ \begin{split} &u_t = \nabla\cdot(D(u)\nabla u)-\chi\nabla\cdot(u\nabla v)+\xi\nabla\cdot(u\nabla w),&\qquad &x\in\Omega,\,t>0, \\ & 0 = \Delta v-\mu_{1}(t)+f_{1}(u),&\qquad &x\in\Omega,\,t>0, \\ &0 = \Delta w-\mu_{2}(t)+f_{2}(u),&\qquad &x\in\Omega,\,t>0 \end{split} \right. \end{equation} $ under homogeneous Neumann boundary conditions in a smooth bounded domain $ \Omega\subset\mathbb{R}^n, \ n\geq2 $. The nonlinear diffusivity $ D $ and nonlinear signal productions $ f_{1}, f_{2} $ are supposed to extend the prototypes $ \begin{equation} \nonumber D(s) = (1+s)^{m-1},\ f_{1}(s) = (1+s)^{\gamma_{1}},\ f_{2}(s) = (1+s)^{\gamma_{2}},\ s\geq0,\gamma_{1},\gamma_{2}>0,m\in\mathbb{R}. \end{equation} $ We proved that if $ \gamma_{1} > \gamma_{2} $ and $ 1+\gamma_{1}-m > \frac{2}{n} $, then the solution with initial mass concentrating enough in a small ball centered at origin will blow up in finite time. However, the system admits a global bounded classical solution for suitable smooth initial datum when $ \gamma_{2} < 1+\gamma_{1} < \frac{2}{n}+m $.

15.
Nat Commun ; 14(1): 329, 2023 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-36658157

RESUMEN

Attempts to develop photocatalysts for hydrogen production from water usually result in low efficiency. Here we report the finding of photocatalysts by integrated interfacial design of stable covalent organic frameworks. We predesigned and constructed different molecular interfaces by fabricating ordered or amorphous π skeletons, installing ligating or non-ligating walls and engineering hydrophobic or hydrophilic pores. This systematic interfacial control over electron transfer, active site immobilisation and water transport enables to identify their distinct roles in the photocatalytic process. The frameworks, combined ordered π skeletons, ligating walls and hydrophilic channels, work under 300-1000 nm with non-noble metal co-catalyst and achieve a hydrogen evolution rate over 11 mmol g-1 h-1, a quantum yield of 3.6% at 600 nm and a three-order-of-magnitude-increased turnover frequency of 18.8 h-1 compared to those obtained with hydrophobic networks. This integrated interfacial design approach is a step towards designing solar-to-chemical energy conversion systems.

16.
Anal Methods ; 14(35): 3434-3443, 2022 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-35993672

RESUMEN

Nowadays, due to the increasing threat of heavy metal ion pollution faced by the environment and living systems, the development of rapid and highly selective methods for the detection of chromium ions (Cr3+) has aroused increasing interest. In this study, copper ferrite nanoparticles (CuFe2O4) immobilized on reduced graphene oxide (CuFe2O4/rGO) were successfully fabricated by a simple co-precipitation method. The catalyst exhibits high peroxidase-like activity with 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic matrix due to its large specific surface area, adsorption performance and abundant catalytic active sites. Based on the excellent peroxidase-like activity of CuFe2O4/rGO and its Cr3+-mediated inhibition controllability, a novel colorimetric assay for the heavy metal Cr3+ was created for the first time. Under optimal experimental conditions, CuFe2O4/rGO can be used as a peroxidase-like nanozyme to achieve the excellent detection of Cr3+ in the range of 0.1-25 µM, and the detection limit is 35 nM. The peroxidase-like CuFe2O4/rGO can provide a general catalytic platform for the application of biomimetic enzymatic catalytic systems and colorimetry, and a new approach has been established for the specific determination of the heavy metal Cr3+.


Asunto(s)
Colorimetría , Nanopartículas , Cromo , Colorimetría/métodos , Colorantes/química , Cobre/química , Compuestos Férricos , Grafito , Peróxido de Hidrógeno/química , Iones , Peroxidasa , Peroxidasas
17.
Dalton Trans ; 51(32): 12314-12323, 2022 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-35900080

RESUMEN

Herein, an atomically dispersed palladium catalyst on a hierarchical porous structure of N-doped carbon (Pd1/N-C) is prepared using a facile freeze-drying-assisted strategy. Freeze-drying methods not only suppress the aggregation of Pd atoms but also successfully produce abundant nanopores. HAADF-STEM confirms that Pd single atoms are uniformly anchored on the N-C surface. The Pd1/N-C electrocatalyst enhances the ORR and OER activity and durability compared to N-C and Pd-NPs/N-C. Rechargeable Zn-air batteries (ZABs) based on novel Pd1/N-C exhibit a peak power density of 113.7 mW cm-2 and maintain a voltage efficiency of 64.0% after 495 cycles at a discharge current density of 5 mA cm-2. Besides, two ZABs in series can supply an LED light for at least 170 h.

18.
Macromol Rapid Commun ; 43(20): e2200393, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35715386

RESUMEN

Covalent-organic frameworks (COFs) are a new class of porous crystalline frameworks with high π-conjugation and periodical skeletons. The highly ordered π-conjugation structures in some COFs allow exciton migration and energy transfer over the frameworks, which leads to good fluorescence probing ability. In this work, two COFs (TFHPB-TAPB-COF and TFHPB-TTA-COF) are successfully condensed via the Schiff base condensation reaction. The intramolecular hydrogen bonds between imine bonds and hydroxyl groups form the excited-state intramolecular proton transfer (ESIPT) strategy. Owing to intramolecular hydrogen bonds in the skeleton, the two COFs show high crystallinity, remarkable stability, and excellent luminescence. The COFs represent a good sensitivity and selectivity to fluoride anions via fluorescence turn-off. Other halogen anions (chloride, bromide, and iodine) and acid anions (nitrate and hydrogen carbonate) remain inactive. These results imply that only fluoride anion is capable of opening the hydrogen bond interaction and hence break the ESIPT strategy. The detection limit toward fluoride anion is down to nanomoles level, ranking the best performances among fluoride anion sensors systems.

19.
Chem Asian J ; 17(15): e202200358, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35607250

RESUMEN

Radioactive iodine in nuclear waste would be harmful to nature and human health. The design of adsorbents for iodine capture with high efficiency still remains a challenge. Herein, two highly conjugated two-dimensional covalent organic frameworks (TFPB-BPTA-COF and TFPB-PyTTA-COF) have been successfully constructed. Both COFs possess high porosity, stability, and a high π-conjugated framework. Impressively, TFPB-PyTTA-COF exhibits an excellent iodine uptake value of up to 5.6 g g-1 , which is superior to most reported COF-based adsorbents for iodine capture.


Asunto(s)
Yodo , Estructuras Metalorgánicas , Neoplasias de la Tiroides , Humanos , Radioisótopos de Yodo , Porosidad
20.
Macromol Rapid Commun ; 43(1): e2100590, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34612557

RESUMEN

Covalent organic frameworks (COFs) are a novel class of crystalline porous polymers, which possess high porosity, excellent stability, and regular nanochannels. 2D COFs provide a 1D nanochannel to form the proton transport channels. The abovementioned features afford a powerful potential platform for designing materials as proton transportation carriers. Herein, the authors incorporate sulfonic acid groups on the pore walls as proton sources for enhancing proton transport conductivity in the 1D channel. Interestingly, the sulfonic acid COFs (S-COFs) electrolytes being binder free exhibit excellent proton conductivity of ≈1.5 × 10-2 S cm-1 at 25 ℃ and 95% relative humidity (RH), which rank the excellent performance in standard proton-conducting electrolytes. The S-COFs electrolytes keep the high proton conduction over the 24 h. The activation energy is estimated to be as low as 0.17 eV, which is much lower than most reported COFs. This research opens a new window to evolve great potential of structural design for COFs as the high proton-conducting electrolytes.


Asunto(s)
Estructuras Metalorgánicas , Electrólitos , Polímeros , Protones , Ácidos Sulfónicos
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