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1.
Chem Pharm Bull (Tokyo) ; 71(2): 154-164, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36724978

RESUMO

Rhodopsins are transmembrane proteins with retinal chromophores that are involved in photo-energy conversion and photo-signal transduction in diverse organisms. In this study, we newly identified and characterized a rhodopsin from a thermophilic bacterium, Bellilinea sp. Recombinant Escherichia coli cells expressing the rhodopsin showed light-induced alkalization of the medium only in the presence of sodium ions (Na+), and the alkalization signal was enhanced by addition of a protonophore, indicating an outward Na+ pump function across the cellular membrane. Thus, we named the protein Bellilinea Na+-pumping rhodopsin, BeNaR. Of note, its Na+-pumping activity is significantly greater than that of the known Na+-pumping rhodopsin, KR2. We further characterized its photochemical properties as follows: (i) Visible spectroscopy and HPLC revealed that BeNaR has an absorption maximum at 524 nm with predominantly (>96%) the all-trans retinal conformer. (ii) Time-dependent thermal denaturation experiments revealed that BeNaR showed high thermal stability. (iii) The time-resolved flash-photolysis in the nanosecond to millisecond time domains revealed the presence of four kinetically distinctive photointermediates, K, L, M and O. (iv) Mutational analysis revealed that Asp101, which acts as a counterion, and Asp230 around the retinal were essential for the Na+-pumping activity. From the results, we propose a model for the outward Na+-pumping mechanism of BeNaR. The efficient Na+-pumping activity of BeNaR and its high stability make it a useful model both for ion transporters and optogenetics tools.


Assuntos
Rodopsina , ATPase Trocadora de Sódio-Potássio , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/química , ATPase Trocadora de Sódio-Potássio/metabolismo , Rodopsina/química , Rodopsina/metabolismo , Transporte de Íons , Bactérias/metabolismo , Íons , Sódio/química , Sódio/metabolismo , Luz
2.
J Adv Res ; 44: 53-70, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36725194

RESUMO

BACKGROUND: With rapid development in agriculture and industry, water polluted with heavy metallic ions has come to be a serious problem. Adsorption-based methods are simple, efficient, and broadly used to eliminate heavy metals. Conventional adsorption materials have the problems of secondary environmental contamination. Hydrogels are considered effective adsorbents, and those prepared from biopolymers are biocompatible, biodegradable, non-toxic, safe to handle, and increasingly used to adsorb heavy metal ions. AIM OF REVIEW: The natural origin and easy degradability of biopolymer hydrogels make them potential for development in environmental remediation. Its water absorption capacity enables it to efficiently adsorb various pollutants in the aqueous environment, and its internal pore channels increase the specific surface area for adsorption, which can provide abundant active binding sites for heavy metal ions through chemical modification. KEY SCIENTIFIC CONCEPT OF REVIEW: As the most representative of biopolymer hydrogels, polysaccharide-based hydrogels are diverse, physically and chemically stable, and can undergo complex chemical modifications to enhance their performance, thus exhibiting superior ability to remove contaminants. This review summarizes the preparation methods of hydrogels, followed by a discussion of the main categories and applications of polysaccharide-based biopolymer hydrogels.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Hidrogéis , Poluentes Químicos da Água/química , Metais Pesados/química , Biopolímeros , Polissacarídeos , Íons , Água
3.
Sci Total Environ ; 865: 161307, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36596421

RESUMO

Research utilizing the model soil nematode Caenorhabditis elegans has revealed that agriculturally relevant nanoparticles (NP), such as zinc oxide NP (ZnONP), cause toxicity at low concentrations and disrupt molecular pathways of pathogen resistance. However, in most nanotoxicity assessments, model organisms are exposed to a single stressor but in nature organisms are affected by multiple sources of stress, including infections, which might exacerbate or mitigate negative effects of NP exposure. Thus, to expand our understanding of the environmental consequences of released NP, this project examined the synergistic/antagonistic effects of ZnONP on C. elegans infected with a common pathogen, Klebsiella pneumoniae. Individual exposures of C. elegans to ZnONP, zinc sulfate (Zn2+ ions) or K. pneumoniae significantly decreased nematode reproduction compared to controls. To assess the combined stress of ZnONP and K. pneumoniae, C. elegans were exposed to equitoxic EC30 concentrations of ZnONP (or Zn ions) and K. pneumoniae. After the combined exposure there was no decrease in reproduction. This complete elimination of reproductive toxicity was unexpected because exposures were conducted at EC30 Zn concentrations and reproductive toxicity due to Zn should have occurred. Amelioration of the pathogen effects by Zn are partially explained by the Zn impact on the K. pneumoniae biofilm. Quantitative assessments showed that external biofilm production and estimated colony forming units (CFU) of K. pneumoniae within the nematodes were significantly decreased. Taken together, our results suggest that during the combined exposure of C. elegans to both stressors Zn in ionic or particulate form inhibits K. pneumoniae ability to colonize nematode's intestine through decreasing pathogen biofilm formation. This highlights the unpredictable nature of combined stressor effects, calling into question the utility of exposures in simplified laboratory media.


Assuntos
Nanopartículas , Óxido de Zinco , Animais , Caenorhabditis elegans , Óxido de Zinco/farmacologia , Klebsiella pneumoniae , Solo , Nanopartículas/toxicidade , Íons/metabolismo
4.
Beijing Da Xue Xue Bao Yi Xue Ban ; 55(1): 44-51, 2023 Feb 18.
Artigo em Chinês | MEDLINE | ID: mdl-36718688

RESUMO

OBJECTIVE: To investigate the preparation of decellularized small intestinal submucosa (dSIS) sponge scaffolds with chelated strontium (Sr) ions at different pH values, and to select the appropriate pH values for synthesizing Sr/dSIS scaffolds using the physicochemical properties and biocompatibility of the scaffolds as evaluation indexes. METHODS: (1) Sr/dSIS scaffolds preparation and grouping: After mixing dSIS solution and strontium chloride solution in equal volumes, adjusting pH of the solution to 3, 5, 7, and 9 respectively, porous scaffolds were prepared by freeze-drying method after full reaction at 37℃, which were named Sr/dSIS-3, -5, -7, and -9 respectively, and the dSIS scaffolds were used as the control group. (2) Physicochemical property evaluation: The bulk morphology of the scaffolds was observed in each group, the microscopic morphology analyzed by scanning electron microscopy, and the porosity and pore size determined, the surface elements analyzed by energy spectroscopy, the structure of functional groups analyzed by infrared spectroscopy, the chelation rate determined by atomic spectrophotometry, the water absorption rate detected by using specific gravity method, and the compression strength evaluated by universal mechanical testing machine.(3) Biocompatibility evaluation: The cytotoxicity and proliferative effect to bone mesenchymal stem cells (BMSCs) of each group were evaluated by Calcein-AM/PI double staining method. RESULTS: Scanning electron microscopy showed that the scaffolds of each group had an interconnected three-dimensional porous structure with no statistical difference in pore size and porosity. Energy spectrum analysis showed that strontium could be detected in Sr/dSIS-5, -7 and -9 groups, and strontium was uniformly distributed in the scaffolds. Functional group analysis further supported the formation of chelates in the Sr/dSIS-5, -7 and -9 groups. Chelation rate analysis showed that the Sr/dSIS-7 group had the highest strontium chelation rate, which was statistically different from the other groups (P < 0.05). The scaffolds in all the groups had good water absorption. The scaffolds in Sr/dSIS-5, -7 and -9 groups showed significantly improved mechanical properties compared with the control group (P < 0.05). The scaffolds in all the groups had good biocompatibility, and the Sr/dSIS-7 group showed the best proliferation of BMSCs. CONCLUSION: When pH was 7, the Sr/dSIS scaffolds showed the highest strontium chelation rate and the best proliferation effect of BMSCs, which was the ideal pH value for the preparation of the Sr/dSIS scaffolds.


Assuntos
Materiais Biocompatíveis , Tecidos Suporte , Tecidos Suporte/química , Estrôncio/química , Estrôncio/farmacologia , Íons , Concentração de Íons de Hidrogênio , Engenharia Tecidual/métodos , Porosidade
5.
Shock ; 59(1): 34-40, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36703276

RESUMO

ABSTRACT: Objective: The ion shift index (ISI), which considers extracellular fluid ions such as phosphate, calcium, and magnesium, represents the ion shift following ischemia; concentrations of these ions are maintained within narrow normal ranges by adenosine triphosphate-dependent homeostasis. The ISI is defined as follows: {potassium (mmol/L-1) + phosphate (mmol/L-1) + Mg (mmol/L-1)}/calcium (mmol/L-1). This study investigated the possibility of predicting the 30-day survival rate of patients who underwent traumatic damage control laparotomy by comparing ISI and other laboratory findings, as well as the initial Trauma and Injury Severity Score (TRISS) and shock indices. Methods: Among the 134 patients who underwent damage control surgery between November 2012 and December 2021, 115 patients were enrolled in this study. Data regarding injury mechanism, age, sex, laboratory findings, vital signs, Glasgow Coma Scale score, Injury Severity Score, Abbreviated Injury Scale score, blood component transfusion, type of surgery, postoperative laboratory outcomes, morbidity, mortality rates, fluids administered, and volume of transfusions were collected and analyzed. Results: In univariate analysis, the odds ratio of the initial ISI was 2.875 (95% confidence interval, 1.52-5.43; P = 0.04), which showed a higher correlation with mortality compared with other indices. The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were derived from different multivariable logistic regression models. The initial ISI had high sensitivity and specificity in predicting patient mortality (AUC, 0.7378). In addition, in the model combining the initial ISI, crystalloids, and TRISS, the AUC showed a high value (AUC, 0.8227). Conclusion: The ISI evaluated using electrolytes immediately after admission in patients undergoing traumatic damage control surgery may be a predictor of patient mortality.


Assuntos
Cálcio , Laparotomia , Humanos , Prognóstico , Estudos Retrospectivos , Curva ROC , Escala de Gravidade do Ferimento , Íons
6.
ACS Macro Lett ; 12(1): 86-92, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36595317

RESUMO

There is growing interest in polymers with high ionic conductivity for applications including batteries, fuel cells, and separation membranes. However, measuring ion diffusion in polymers can be challenging, requiring complex procedures and instrumentation. Here, a simple strategy to study ion diffusion in polymers is presented that utilizes ion-chromic spiropyan as an indicator to measure the diffusion of LiTFSI, KTFSI, and NaTFSI within poly(ethylene oxide)-based polymer networks. These systems are selected, as these are common ions and polymers used in energy storage applications, however, the approach described is not specific to materials for energy storage. Specifically, to enabling the study of ion diffusion, these salts cause the spiropyran to undergo an isomerization reaction, which results in a significant color change. This colorimetric response enables the determination of the diffusion coefficients of these ions within films of these polymers simply by optically tracking the spatial-temporal evolution of the isomerization product within the film and fitting the data to the relevant diffusion equations. The simplicity of the method makes it amenable to the study of ion diffusion in polymers under a range of conditions, including various temperatures and under macroscopic deformation.


Assuntos
Polímeros , Sais , Íons , Temperatura , Difusão
7.
Anal Bioanal Chem ; 415(5): 749-758, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36622393

RESUMO

Electrospray ionization mass spectrometry (ESI-MS) experiments, including ion mobility spectrometry mass spectrometry (ESI-IMS-MS) and electron capture dissociation (ECD) of proteins ionized from aqueous solutions, have been used for the study of solution-like structures of intact proteins. By mixing aqueous proteins with denaturants online before ESI, the amount of protein unfolding can be precisely controlled and rapidly analyzed, permitting the characterization of protein folding intermediates in protein folding pathways. Herein, we mixed various pH solutions online with aqueous cytochrome C for unfolding and characterizing its unfolding intermediates with ESI-MS charge state distribution measurements, IMS, and ECD. The presence of folding intermediates and unfolded cytochrome c structures were detected from changes in charge states, arrival time distributions (ATDs), and ECD. We also compared structures from nondenaturing and denaturing solution mixtures measured under "gentle" (i.e., low energy) ion transmission conditions with structures measured under "harsh" (i.e., higher energy) transmission. This work confirms that when using "gentle" instrument conditions, the gas-phase cytochrome c ions reflect attributes of the various solution-phase structures. However, "harsh" conditions that maximize ion transmission produce extended structures that no longer correlate with changes in solution structure.


Assuntos
Citocromos c , Espectrometria de Mobilidade Iônica , Citocromos c/química , Elétrons , Proteínas/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Desdobramento de Proteína , Ácidos , Íons/química , Água
8.
Chem Commun (Camb) ; 59(8): 1082-1085, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36621890

RESUMO

In situ polymerization of acrylonitrile and graphene oxide in combination with thermal treatment was readily performed to produce robust hierarchical hybrids containing flower-like oxidized-polyacrylonitrile, which synergistically couple conductive graphene and a multi-electron redox-active matrix, affording large reversible capacity, high rate capability, and long cycle life toward cost-efficient and sustainable batteries.


Assuntos
Grafite , Lítio , Resinas Acrílicas , Eletrodos , Íons
9.
Nanotechnology ; 34(14)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36623312

RESUMO

In this study, composite asymmetric membranes containing antimony (Sb) nanobelts are prepared via a straightforward phase inversion method in combination with post-pyrolysis treatment. Sb nanobelt asymmetric membranes demonstrate improved cyclability and specific capacity as the alloy anode of sodium ion battery compared to Sb nanobelt thin films without asymmetric porous structure. The unique structure can effectively accommodate the large volume expansion of Sb-based alloy anodes, prohibit the loss of fractured active materials, and aid in the formation of stable artificial solid electrolyte interphases as evidenced by an outstanding capacity retention of ∼98% in 130 cycles at 60 mA g-1. A specific capacity of ∼600 mAh g-1is obtained at 15 mA g-1(1/40C). When the current density is increased to 240 mA g-1, ∼80% capacity can be maintained (∼480 mAh g-1). The relations among phase inversion conditions, structures, compositions, and resultant electrochemical properties are revealed through comprehensive characterization.


Assuntos
Antimônio , Sódio , Íons , Ligas , Fontes de Energia Elétrica
10.
Science ; 379(6628): 161-167, 2023 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-36634187

RESUMO

Fine-tuned ion transport across nanoscale pores is key to many biological processes, including neurotransmission. Recent advances have enabled the confinement of water and ions to two dimensions, unveiling transport properties inaccessible at larger scales and triggering hopes of reproducing the ionic machinery of biological systems. Here we report experiments demonstrating the emergence of memory in the transport of aqueous electrolytes across (sub)nanoscale channels. We unveil two types of nanofluidic memristors depending on channel material and confinement, with memory ranging from minutes to hours. We explain how large time scales could emerge from interfacial processes such as ionic self-assembly or surface adsorption. Such behavior allowed us to implement Hebbian learning with nanofluidic systems. This result lays the foundation for biomimetic computations on aqueous electrolytic chips.


Assuntos
Sinapses , Água , Íons , Transporte de Íons , Memória de Longo Prazo
11.
Science ; 379(6628): 143-144, 2023 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-36634195

RESUMO

Ionic computing raises the possibility of devices that operate similarly to the human brain.


Assuntos
Nanotecnologia , Humanos , Íons
12.
Nat Commun ; 14(1): 84, 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36604414

RESUMO

Nuclear magnetic resonance relaxometry represents a powerful tool for extracting dynamic information. Yet, obtaining links to molecular motion is challenging for many ions that relax through the quadrupolar mechanism, which is mediated by electric field gradient fluctuations and lacks a detailed microscopic description. For sodium ions in aqueous electrolytes, we combine ab initio calculations to account for electron cloud effects with classical molecular dynamics to sample long-time fluctuations, and obtain relaxation rates in good agreement with experiments over broad concentration and temperature ranges. We demonstrate that quadrupolar nuclear relaxation is sensitive to subpicosecond dynamics not captured by previous models based on water reorientation or cluster rotation. While ions affect the overall water retardation, experimental trends are mainly explained by dynamics in the first two solvation shells of sodium, which contain mostly water. This work thus paves the way to the quantitative understanding of quadrupolar relaxation in electrolyte and bioelectrolyte systems.


Assuntos
Sódio , Água , Sódio/química , Íons/química , Espectroscopia de Ressonância Magnética , Água/química , Eletrólitos
13.
Top Curr Chem (Cham) ; 381(1): 7, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36607442

RESUMO

The incorporation of aryl substituents at the meso-positions of calix[4]pyrrole (C4P) scaffolds produces aryl-extended (AE) and super-aryl-extended (SAE) calix[4]pyrroles. The cone conformation of the all-α isomers of "multi-wall" AE-C4Ps and SAE-C4Ps displays deep aromatic clefts or cavities. In particular, "four-wall" receptors feature an aromatic polar cavity closed at one end with four convergent pyrrole rings and fully open at the opposite end. This makes AE- and SAE-C4P scaffolds effective receptors for the molecular recognition of negatively charged ions and neutral guest molecules with donor-acceptor and hydrogen bonding motifs. In addition, adequately functionalized all-α isomers of multi wall AE- and SAE-C4P scaffolds self-assemble into uni-molecular and supra-molecular aggregates displaying capsular and cage-like structures. The self-assembly process requires the presence of template ions or molecules that lock the C4P cone conformation and complementing the inner polar functions and volumes of their cavities. We envisioned performing an in-depth revision of AE- and SAE-C4P scaffolds owing to their importance in different domains such as supramolecular chemistry, biology, material sciences and pharmaceutical chemistry. Herewith, besides the synthetic details on the elaboration of their structures, we also draw attention to their diverse applications. The organization of this review is mainly based on the number of "walls" present in the AE-C4P derivatives and their structural modifications. The sections are further divided based on the C4P functions and applications. The authors are convinced that this review will be of interest to researchers working in the general area of supramolecular chemistry as well as those involved in the study of the binding properties and applications of C4P derivatives.


Assuntos
Porfirinas , Pirróis , Pirróis/química , Porfirinas/química , Modelos Moleculares , Íons/química , Conformação Molecular
14.
Sci Rep ; 13(1): 437, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624146

RESUMO

Eggshells offer many advantages as adsorbents, such as affordability without special preparations other than pulverization and calcination. However, the manufacturing industry generally has a severe problem with high concentrations of heavy metals in wastewater. The purpose of this study was to use eggshell byproducts and calcined eggshell treatment for the adsorption of copper in an aqueous solution. The reaction time, metal concentration, adsorbent dose, temperature, and pH were evaluated using primary factors followed by the response surface method (RSM) to investigate the optimum conditions for eggshell byproducts and calcined eggshell adsorption treatment. The results of the one-factor-at-a-time experiment showed that the optimal adsorption rate was obtained from treatment at 24 h, 25 mg/L, 10 mg, and 25 °C. In addition, the effect of pH on the adsorption rates of eggshells and eggshells with membrane were detected at pH values of 5 and 5.9 and found to be 95.2, 90.5, and 73.3%. The reaction surface experiment showed that the best adsorption rate reached 99.3% after calcination at 900 °C for 2 h and a 20 min reaction. The results showed that eggshells, eggshell membranes, eggshells with membrane, and calcined eggshells could be applied to remove copper ions from industrial wastewater. The adsorption capacity of the calcined eggshell is better than that of the non-calcined eggshell and has good neutrality in acidic industrial wastewater. Therefore, it is convenient and practical for practical production and application. Likewise, this study conveys promising findings in the context of improving wastewater treatment based on a circular economy approach to waste reuse in the food industry and represents a valuable direction for future research.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Animais , Cobre , Casca de Ovo/química , Água , Adsorção , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise , Cinética , Íons
15.
Environ Monit Assess ; 195(2): 254, 2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36592254

RESUMO

This study used red mud modified with chitosan (RM/CS) as a novel adsorbent to remove Ni(II) ions from an aqueous solution. The adsorbent was characterized by the techniques of the BET method, X-ray diffraction (XRD), and scanning electron microscopy (SEM) analysis. According to the findings, the surface area of RM/CS is nearly doubled compared to CS, from 68.6 to 105.7 m2.g-1. The Ni(II) batch adsorption of RM/CS was performed as a function of pH value, contact time, and volume of adsorbent. Three isotherm adsorption models (Langmuir, Freundlich, and Sips) and three kinetic models (the pseudo-first-order, the pseudo-second-order, and the intra-diffusion models) were fitted with the experimental data to calculate the maximum adsorption capacity and to estimate the uptake in nature. The Langmuir monolayer adsorption capacity for Nickel (II) is 31.66 mg.g-1 at a pH of 6.0, with an adsorption time of 180 min and a temperature of 323 K. The Ni(II) adsorption on RM/CS is the exothermic process and is controlled by the intra-diffusion model.


Assuntos
Quitosana , Poluentes Químicos da Água , Quitosana/química , Monitoramento Ambiental , Níquel/química , Temperatura , Íons , Adsorção , Cinética , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química , Termodinâmica
16.
Anal Chem ; 95(2): 1652-1662, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36594613

RESUMO

In-source fragmentation (ISF) is a naturally occurring phenomenon in various ion sources including soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI). It has traditionally been minimized as it makes the dataset more complex and often leads to mis-annotation of metabolites. Here, we introduce an approach termed PICA (for pixel intensity correlation analysis) that takes advantage of ISF in MALDI imaging to increase confidence in metabolite identification. In PICA, the extraction and association of in-source fragments to their precursor ion results in "pseudo-MS/MS spectra" that can be used for identification. We examined PICA using three different datasets, two of which were published previously and included validated metabolites annotation. We show that highly colocalized ions possessing Pearson correlation coefficient (PCC) ≥ 0.9 for a given precursor ion are mainly its in-source fragments, natural isotopes, adduct ions, or multimers. These ions provide rich information for their precursor ion identification. In addition, our results show that moderately colocalized ions (PCC < 0.9) may be structurally related to the precursor ion, which allows for the identification of unknown metabolites through known ones. Finally, we propose three strategies to reduce the total computation time for PICA in MALDI imaging. To conclude, PICA provides an efficient approach to extract and group ions stemming from the same metabolites in MALDI imaging and thus allows for high-confidence metabolite identification.


Assuntos
Espectrometria de Massas em Tandem , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Íons
17.
Dalton Trans ; 52(4): 909-918, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36594631

RESUMO

A two-dimensional (2D) cobalt(II) metal-organic framework (MOF) constructed by a ditopic organic ligand, formulated as {[Co(Hbic)(H2O)]·4H2O}n (1) (H2bic = 1H-benzimidazole-5-carboxylic acid), was hydrothermally synthesized and structurally characterized. Single-crystal X-ray diffraction shows that the distorted octahedral Co2+ ions, as coordination nodes, are bridged to form 2D honeycomb networks, which are further organized into a 3D supramolecular porous framework through multiple hydrogen bonds and interlayer π-π interactions. Dynamic crystallography experiments reveal the anisotropic thermal expansion behavior of the lattice, suggesting a flexible hydrogen-bonded 3D framework. Interestingly, hydrogen-bonded (H2O)4 tetramers were found to be located in porous channels, yielding 1D proton transport pathways. As a result, the compound exhibited a high room-temperature proton conductivity of 1.6 × 10-4 S cm-1 under a relative humidity of 95% through a Grotthuss mechanism. Magnetic investigations combined with theoretical calculations reveal giant easy-plane magnetic anisotropy of the distorted octahedral Co2+ ions with the experimental and computed D values being 87.1 and 109.3 cm-1, respectively. In addition, the compound exhibits field-induced slow magnetic relaxation behavior at low temperatures with an effective energy barrier of Ueff = 45.2 cm-1. Thus, the observed electrical and magnetic properties indicate a rare proton conducting SIM-MOF. The foregoing results provide a unique bifunctional cobalt(II) framework material and suggest a promising way to achieve magnetic and electrical properties using a supramolecular framework platform.


Assuntos
Cobalto , Prótons , Cobalto/química , Temperatura , Porosidade , Íons , Fenômenos Magnéticos
18.
J Radiol Prot ; 43(1)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36599152

RESUMO

Hadron radiation therapy is of great interest worldwide. Heavy-ion beams provide ideal therapeutic conditions for deep-seated local tumours. At the Heidelberg Ion Beam Therapy Center (HIT, Germany), protons and carbon ions are already integrated into the clinical routine, while16O ions are still used for research only. To ensure the protection of the technical staff and members of the public, it is required to estimate the neutron dose distribution for optimal working conditions and at different locations. The Particle and Heavy Ion Transport Code System (PHITS) is used in this work to evaluate the dose rate distribution of secondary neutrons in a treatment room at HIT where16O ions are used: an equivalent target in soft tissue is considered in the shielding assessment to simulate the interaction of the beam with patients. The angular dependence of neutron fluences and energy spectra around the considered phantom were calculated. Alongside the spatial distribution of the neutron and photon fluence, a map of the effective dose rate was estimated using the ICRP fluence-to-effective dose conversion coefficients, exploiting the PHITS code's built-in capabilities. The capability of the actual shielding design of the studied HIT treatment room was approved.


Assuntos
Nêutrons , Humanos , Doses de Radiação , Método de Monte Carlo , Transporte de Íons , Íons
19.
Chem Commun (Camb) ; 59(8): 1038-1041, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36602009

RESUMO

The ability of spectator metal ions such as vanadium to enhance the electrochemical performance of supercapacitors has been explained. Vanadium-incorporated CoO(OH) combined with NiMn-layered double hydroxide (LDH) yields a specific capacitance of 1700 F g-1 at 1 A g-1 with 96% retention after 5000 cycles. The assembled asymmetric supercapacitor exhibits an energy density of 45.93 W h Kg-1 and a power density of 752 W kg-1@1 A g-1.


Assuntos
Óxidos , Vanádio , Oxirredução , Íons
20.
Chem Commun (Camb) ; 59(8): 1066-1069, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36606800

RESUMO

A Li6PS5Cl-rich composite is prepared using a PEG-borate ester solid-state polymer electrolyte (BSPE). BSPE is a highly accessible compound with high ionic conductivity and excellent electrochemical stability against Li metal. Thereby, the stability of the Li6PS5Cl-rich composite with BSPE improved significantly.


Assuntos
Boratos , Eletrólitos , Íons , Lítio , Metais , Ésteres , Polímeros
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