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1.
Fish Shellfish Immunol ; 149: 109551, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38599363

RESUMEN

The present study aimed to evaluate the effect of king oyster mushroom (Pleurotus eryngii) root waste and soybean meal co-fermented protein (CFP) on growth performance, feed utilization, immune status, hepatic and intestinal health of largemouth bass (Micropterus salmoides). Largemouth bass (12.33 ± 0.18 g) were divided into five groups, fed with diets containing 0 %, 5 %, 10 %, 15 % and 20 % CFP respectively for 7 weeks. The growth performance and dietary utilization were slightly improved by the supplementation of CFP. In addition, improved immunoglobulin M (IgM) content and lysozyme activity in treatments confirm the enhancement of immunity in fish by the addition of CFP, especially in fish fed 20 % CFP (P < 0.05). Furthermore, CFP significantly improved liver GSH (glutathione) content in groups D10 and D15 (P < 0.05), and slightly improved total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity while slightly reduced malondialdehyde (MDA) content. Simultaneously, the upregulation of lipolysis-related genes (PPARα, CPT1 and ACO) expression and downregulation of lipid synthesis-related genes (ACC and DGAT1) expression was recorded in the group D20 compared with the control (P < 0.05), which were consistent with the decreased liver lipid contents, suggests that lipid metabolism was improved by CFP. In terms of intestinal structural integrity, ameliorated intestinal morphology in treatments were consistent with the upregulated Occludin, Claudin-1 and ZO-1 genes expression. The intestinal pro-inflammatory cytokines (TNF-α and IL-8) expression were suppressed while the anti-inflammatory cytokines (IL-10 and TGF-ß) were activated in treatments. The expression of antimicrobial peptides (Hepcidin-1, Piscidin-2 and Piscidin-3) and intestinal immune effectors (IgM and LYZ) were slightly up-regulated in treatments. Additionally, the relative abundance of intestinal beneficial bacteria (Firmicutes) increased while the relative abundance of potential pathogenic bacteria (Fusobacterium and Proteobacteria) decreased, which indicated that the intestinal microbial community was well-reorganized by CFP. In conclusion, dietary CFP improves growth, immunity, hepatic and intestinal health of largemouth bass, these data provided a theoretical basis for the application of this novel functional protein ingredient in fish.


Asunto(s)
Alimentación Animal , Lubina , Dieta , Suplementos Dietéticos , Glycine max , Hígado , Pleurotus , Animales , Lubina/inmunología , Lubina/crecimiento & desarrollo , Alimentación Animal/análisis , Dieta/veterinaria , Pleurotus/química , Glycine max/química , Hígado/inmunología , Hígado/efectos de los fármacos , Hígado/metabolismo , Suplementos Dietéticos/análisis , Intestinos/inmunología , Intestinos/efectos de los fármacos , Fermentación , Inmunidad Innata/efectos de los fármacos , Distribución Aleatoria , Raíces de Plantas/química , Relación Dosis-Respuesta a Droga
2.
Chemistry ; 29(17): e202203835, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36581566

RESUMEN

The reliable self-assembly of microporous metal-phosphonate materials remains a longstanding challenge. This stems from, generally, more coordination modes for the functional group allowing more dense structures, and stronger bonding driving less crystalline products. Here, a novel orthogonalized aryl-phosphonate linker, 1,3,5-tris(4'-phosphono-2',6'-dimethylphenyl) benzene (H6 L3) has been used to direct formation of open frameworks. The peripheral aryl rings of H6 L3 are orthogonalized relative to the central aromatic ring giving a tri-cleft conformation of the linker in which small aromatic molecules can readily associate. When coordinated to magnesium ions, a series of porous crystalline metal-organic, and hydrogen-bonded metal-organic frameworks (MOFs, HMOFs) are formed (CALF-41 (Mg), HCALF-42 (Mg), -43 (Mg)). While most metal-organic frameworks are tailored based on choice of metal and linker, here, the network structures are highly dependent on the inclusion and structure of the guest aromatic compounds. Larger guests, and a higher stoichiometry of metal, result in increased solvation of the metal ion, resulting in networks with connectivities increasingly involving hydrogen-bonds rather than direct phosphonate coordination. Upon thermal activation and aromatic template removal, the materials exhibit surface areas ranging from 400-600 m2 /g. Self-assembly in the absence of aromatic guests yields mixtures of phases, frequently co-producing a dense 3-fold interpenetrated structure (1). Interestingly, a series of both more porous (530-900 m2 /g), and more robust solids is formed by complexing with trivalent metal ions (Al, Ga, In) with aromatic guest; however, these are only attainable as microcrystalline powders. The polyprotic nature of phosphonate linkers enables structural analogy to the divalent analogues and these are identified as CALF-41 analogues. Finally, insights to the structural transformations during metal ion desolvation in this family are gained by considering a pair of structurally related Co materials, whose hydrogen-bonded (HCALF-44 (Co)) and desolvated (CALF-44 (Co)) coordination bonded networks were fully structurally characterized.

3.
Angew Chem Int Ed Engl ; 62(15): e202300786, 2023 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-36792541

RESUMEN

Natural light-harvesting (LH) systems can divide identical dyes into unequal aggregate states, thereby achieving intelligent "allocation of labor". From a synthetic point of view, the construction of such kinds of unequal and integrated systems without the help of proteinaceous scaffolding is challenging. Here, we show that four octatetrayne-bridged ortho-perylene diimide (PDI) dyads (POPs) self-assemble into a quadruple assembly (POP)4 both in solution and in the solid state. The two identical PDI units in each POP are compartmentalized into weakly coupled PDIs (P520) and closely stacked PDIs (P550) in (POP)4 . The two extreme pools of PDI chromophores were unambiguously confirmed by single-crystal X-ray crystallography and NMR spectroscopy. To interpret the formation of the discrete quadruple assembly, we also developed a two-step cooperative model. Quantum-chemical calculations indicate the existence of multiple couplings within and across P520 and P550, which can satisfactorily describe the photophysical properties of the unequal quadruple assembly. This finding is expected to help advance the rational design of dye stacks to emulate functions of natural LH systems.

4.
Chemistry ; 28(31): e202200874, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35349770

RESUMEN

The coordinative pliancy of the phosphonate functional group means that metal-phosphonate materials often self-assemble as well-packed structures with minimal porosity, as efficient inter-ligand packing is enabled. Here, we report a multistep synthesis of a novel aryl-phosphonate linker with an orthogonalized ligand core, 1,3,5-tris(4'-phosphonophenyl)-2,4,6-trimethylbenzene (H6 L2) designed to form more open structures. A series of crystalline metal-phosphonate frameworks (CALF-35 to -39) have been assembled by coordinating to divalent metals (Ba, Sr, Ca, Mg, Zn). H6 L2 is unable to pack efficiently and, as a consequence, yields several distinct microporous structures. The resulting structures are discussed in detail, with a focus on the solid-state packing of the sterically rigidified linker. Combined with larger cations (Sr, and Ba), H6 L2 packs in a parallel-offset manner, yielding isomorphous and microporous metal-organic frameworks (CALF-35 (Sr), and (Ba)). When coordinated to smaller metals (Ca, Mg, Zn), H6 L2 forms four new structures. Two Ca MOFs of different stoichiometry, (CALF-36 and 37) and a Mg MOF CALF-38 show narrow pores and have high selectivities for CO2 over N2 and CH4 . Finally, in CALF-39 (Zn), H6 L2 linkers pack in a herringbone fashion, resulting in a material with 10.9×10.1 Å2 square channels. The stability of all structures was tested, and the most porous structure, CALF-39 (Zn), was found to retain its structure and gas adsorption after immersion in water over pH 3-11.


Asunto(s)
Estructuras Metalorgánicas , Organofosfonatos , Ligandos , Estructuras Metalorgánicas/química , Metales/química , Porosidad
5.
Angew Chem Int Ed Engl ; 60(46): 24543-24548, 2021 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-34291529

RESUMEN

The synthesis, structures, and properties of [4]cyclonaphthodithiophene diimides ([4]C-NDTIs) are described. NDTIs as important n-type building blocks were catenated in the α-positions of thiophene rings via an unusual electrochemical-oxidation-promoted macrocyclization route. The thiophene-thiophene junction in [4]C-NDTIs results in an ideal pillar shape. This interesting topology, along with appealing electronic and optical properties inherited from the NDTI units, endows the [4]C-NDTIs with both near-infrared (NIR) light absorptions, strong excitonic coupling, and tight encapsulation of C60 . Stable orientations of the NDTI units in the nanopillars lead to stable inherent chirality, which enables detailed circular dichroism studies on the impact of isomeric structures on π-conjugation. Remarkably, the [4]C-NDTIs maintain the strong π-π stacking abilities of NDTI units and thus adopt two-dimensional (2D) lattice arrays at the molecular level. These nanopillar molecules have great potential to mimic natural photosynthetic systems for the development of multifunctional organic materials.

6.
J Am Chem Soc ; 142(8): 3712-3717, 2020 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-32036654

RESUMEN

Conventionally, z-direction modulation of two-dimensional covalent organic frameworks (2D-COFs) is difficult to achieve because they rely on spontaneous π-π interactions to form 3D architectures. Herein, we report a facile construction of a novel intercalated covalent organic framework (Intercalated-COF) by synchronizing operations of supramolecular donor-acceptor (D-A) interactions (A unit: 2,5,8,11-tetra(p-formylphenyl)-perylene diimide (PDI) 1; D unit: perylene 3, as intercalator) in the vertical directions, with polymerizations (by only reacting 1 with p-phenylenediamine 2) in the lateral directions. In this Intercalated-COF, the PDI-based covalent 2D layers are uniformly separated by perylene guest layers. This supramolecular strategy opens the possibility for z-direction modulation of 2D-COFs through "intercalating" various guest molecules and thus may contribute to the exploration of advanced applications of these porous and crystalline frameworks.

7.
J Biol Inorg Chem ; 25(5): 759-776, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32583226

RESUMEN

The potential chemotherapeutic properties coupled to photochemical transitions make the family of fac-[Re(CO)3(N,N)X]0/+ (N,N = a bidentate diimine such as 2,2'-bipyridine (bpy); X = halide, H2O, pyridine derivatives, PR3, etc.) complexes of special interest. We have investigated reactions of the aqua complex fac-[Re(CO)3(bpy)(H2O)](CF3SO3) (1) with potential anticancer activity with the amino acid L-cysteine (H2Cys), and its derivative N-acetyl-L-cysteine (H2NAC), as well as the tripeptide glutathione (H3A), under physiological conditions (pH 7.4, 37 °C), to model the interaction of 1 with thiol-containing proteins and enzymes, and the impact of such coordination on its photophysical properties and cytotoxicity. We report the syntheses and characterization of fac-[Re(CO)3(bpy)(HCys)]·0.5H2O (2), Na(fac-[Re(CO)3(bpy)(NAC)]) (3), and Na(fac-[Re(CO)3(bpy)(HA)])·H2O (4) using extended X-ray absorption spectroscopy, IR and NMR spectroscopy, electrospray ionization spectrometry, as well as the crystal structure of {fac-[Re(CO)3(bpy)(HCys)]}4·9H2O (2 + 1.75 H2O). The emission spectrum of 1 displays a variance in Stokes shift upon coordination of L-cysteine and N-acetyl-L-cysteine. Laser excitation at λ = 355 nm of methanol solutions of 1-3 was followed by measuring their ability to produce singlet oxygen (1O2) using direct detection methods. The cytotoxicity of 1 and its cysteine-bound complex 2 was assessed using the MDA-MB-231 breast cancer cell line, showing that the replacement of the aqua ligand on 1 with L-cysteine significantly reduced the cytotoxicity of the Re(I) tricarbonyl complex. Probing the cellular localization of 1 and 2 using X-ray fluorescence microscopy revealed an accumulation of 1 in the nuclear and/or perinuclear region, whereas the accumulation of 2 was considerably reduced, potentially explaining its reduced cytotoxicity. Replacing the aqua ligand with cysteine in the antitumor active fac-[Re(CO)3(bpy)(H2O)](CF3SO3) complex significantly reduced its cellular accumulation and cytotoxicity against the MDA-MB-213 breast cancer cell line, shifted its maximum emission to considerably higher energies, and decreased its fluorescence quantum yield.


Asunto(s)
Antineoplásicos/farmacología , Complejos de Coordinación/farmacología , Cisteína/farmacología , Renio/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Monóxido de Carbono/análisis , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Cisteína/química , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Conformación Molecular , Renio/química , Relación Estructura-Actividad , Células Tumorales Cultivadas
8.
Zhongguo Yi Liao Qi Xie Za Zhi ; 44(5): 457-462, 2020 Oct 08.
Artículo en Zh | MEDLINE | ID: mdl-33047574

RESUMEN

Through the functional combination of relevant departments involved in hospital procurement, to simplify and unify the work process, we establish a standardized procurement system, to realize the pre-procurement budget and approval, power balance, strengthen the fairness and openness of procurement process. By introducing the closed-loop process of in-process supervision to ensure the impartiality of review and post-evaluation control, it comprehensively strengthens the internal control of procurement management, and finally realizes the purpose of strengthening procurement risk prevention and procurement quality management.


Asunto(s)
Hospitales Públicos , Departamento de Compras en Hospital , Control de Calidad , Investigación
9.
J Am Chem Soc ; 141(2): 1045-1053, 2019 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-30582892

RESUMEN

Overcoming the brittleness of metal-organic frameworks (MOFs) is a challenge for industrial applications. To increase the mechanical strength, MOFs have been blended with polymers to form composites. However, this also brings challenges, such as integration and integrity of MOF in the composite, which can hamper the selectivity of gas separations. In this report, an "all MOF" material with mechanical flexibility has been prepared by covalent cross-linking of metal-organic polyhedra (MOPs). The ubiquitous Cu24 isophthalate MOP has been decorated with a long alkyl chain having terminal alkene functionalities so that MOPs can be cross-linked via olefin metathesis using Grubbs second generation catalyst. Different degrees of cross-linked MOP materials have been obtained by varying the amount of catalyst in the reaction. Rheology of these structures with varying number of cross-links was performed to assess the cross-link density and its homogeneity throughout the sample. The mechanical properties were further investigated by the nanoindentation method, which showed increasing hardness with higher cross-link density. Thus, this strategy of cross-linking MOPs with covalent flexible units allows us to create MOFs of increasing mechanical strength while retaining the MOP cavities.

10.
Chemistry ; 25(17): 4305-4308, 2019 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-30723967

RESUMEN

Isolable cationic PtII and PtIV alkylidenes, proposed intermediates in catalytic organic transformations, are reported. The bonding in these species was probed by experimental, structural, spectroscopic, electrochemical and computational methods, providing direct evidence for π-bonding, the often-theorized relativistic stabilization of these species, and the influence of oxidation state.

11.
Inorg Chem ; 58(15): 9874-9881, 2019 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-31335137

RESUMEN

Metal-organic polyhedra (MOPs) are increasingly studied as host-guest capsules, linked into networks, or incorporated into composite materials. As such, understanding the decomposition of MOP structures is of fundamental importance. The degradation of the ubiquitous copper(II) MOP Cu24[5-(hydroxy)isophthalate]24 (1) is studied in liquid water. At different intervals of water exposure, powder X-ray diffraction (PXRD) is performed and stepwise conversion of the MOP into three different coordination polymers is observed. First, the formation of a 2D coordination polymer, 2, is observed, which upon further exposure gives a 1D coordination polymer, 3, and finally a trinuclear copper(II) complex, 4. Compound 2 is characterized by PXRD owing to its transient nature, while 3 and 4 are characterized crystallographically. The final structure, 4, contains copper(II) trimers, and so its magnetic behavior is also investigated.

12.
Inorg Chem ; 58(9): 6246-6256, 2019 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-30997801

RESUMEN

Three Co(II) metal-organic frameworks, namely, {[Co2(L)2(OBA)2(H2O)4]· xG} n (1), {[Co(L)0.5(OBA)]· xG} n (2), and {[Co2(L)2(OBA)2(H2O)]·DMA· xG} n (3) [where L = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene, H2OBA = 4,4'-oxybisbenzoic acid, DMF = dimethylformamide, DMA = dimethylacetamide, and G denotes disordered guest molecules], have been synthesized under diverse reaction conditions through self-assembly of a bent dicarboxylate and a linear spacer with a Co(II) ion. While 1 is crystallized at room temperature in DMF to form a 2D layer structure, 2 is formed by the assembly of similar components under solvothermal conditions with a 3D network structure. On the other hand, changing the solvent to DMA, 3 could be crystallized at room temperature with a 3D architecture. Out of the three, activated sample 2 was found to be permanently microporous in nature, with a BET surface area of 385 m2/g, and exhibited moderately high uptake capacity for C2H2 and CO2 while taking up much less CH4 and N2 at ambient conditions. As a result, high ideal adsorbed solution theory (IAST) separation selectivities are obtained for CO2/N2 (15:85), CO2/CH4 (50:50), and C2H2/CH4 (50:50) gas mixtures, making 2 a potential candidate for those important gas separations at ambient conditions. Moreover, the magnetic properties of 1-3 were studied. 1 and 2 show antiferromagnetic interaction between the Co(II) centers, whereas 3 displays ferromagnetic behavior arising from a counter-complementary effect between two types of links among Co(II) centers in 3.

13.
Angew Chem Int Ed Engl ; 58(43): 15273-15277, 2019 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-31436902

RESUMEN

The formation of well-defined finite-sized aggregates represents an attractive goal in supramolecular chemistry. In particular, construction of discrete π-stacked dye assemblies remains a challenge. Reported here is the design and synthesis of a novel type of discrete π-stacked aggregate from two comparable perylenediimide (PDI) dyads (PEP and PBP). The criss-cross PEP-PBP dimers in solution and (PBP-PEP)-(PEP-PBP) tetramers in the solid state are well elucidated using single-crystal X-ray diffraction, dynamic light scattering, and diffusion-ordered NMR spectroscopy. Extensive π-π stacking between the PDI units of PEP and PBP as well as repulsive interactions of swallow-tailed alkyl substituents are responsible for the selective formation of discrete dimer and tetramer stacks. Our results reveal a new approach to preparing discrete π stacks that are appealing for making assemblies with well-defined optoelectronic properties.

14.
J Am Chem Soc ; 139(21): 7176-7179, 2017 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-28510427

RESUMEN

A sulfonated indium (In) metal organic framework (MOF) is reported with an anionic layered structure incorporating hydrogen-bonded dimethylammonium cations and water molecules. The MOF becomes amorphous in >60% relative humidity; however, impedance analysis of pelletized powders revealed a proton conduction value of over 10-3 S cm-1 at 25 °C and 40% RH, a very high proton conduction value for low humidity and moderate temperature. Given the modest humidity stability of the MOF, triaxial impedance analyses on a single crystal was performed and confirmed bulk proton conductivity over 10-3 S cm-1 along two axes corroborating the data from the pellet.

15.
Zhongguo Yi Liao Qi Xie Za Zhi ; 41(1): 70-2, 2017 Jan.
Artículo en Zh | MEDLINE | ID: mdl-29792790

RESUMEN

Under the concept of Internet+, this paper proposed modern medical equipment management system, which could satisfy our hospital and also agree with the evaluation of 3A hospital. The system can monitor, analyze and effectively manage the whole life of the equipment that included assembly, use, maintenance, update and rejection. The system mainly includes eleven modules that are equipment management, repair management, online-repair management, PM management, metering management, benefit analysis, guarantee management, supporter management, barcode management, inventory management and inspection management. The system could help to manage medical equipment effectively and optimize resource a location.


Asunto(s)
Equipos y Suministros de Hospitales , Internet , Mantenimiento , Monitoreo Fisiológico
16.
Chemistry ; 22(34): 12088-94, 2016 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-27383009

RESUMEN

A series of highly connected metal-organic frameworks (MOFs), [Co8 (O)(OH)4 (H2 O)4 (ina)8 ](NO3 )2 ⋅2 C2 H5 OH⋅4 H2 O (1), [Co8 (O)(OH)4 (H2 O)4 (pba)8 ](NO3 )2 ⋅8 C2 H5 OH⋅28 H2 O (2), and [Co8 (O)(OH)4 (H2 O)4 (pbba)8 ](NO3 )2 ⋅guest (3), in which ina=isonicotinate, pba=4-pyridylbenzoate, and pbba=4-(pyridine-4-yl)phenylbenzoate, is reported. These MOFs contain a new secondary building unit (SBU), with a square Co4 (µ4 -O) central unit having the rare µ4 -O(2-) motif, which is decorated by the other four peripheral cobalt atoms through µ3 -OH in a windmill-like shape. This SBU holds 16 divergent connecting organic ligands, pyridyl-carboxylates, to form three different frameworks. The high porosity of desolvated 2 is shown by the efficient gas absorption of N2 , CO2 , CH4 , and H2 . In addition, 1 and 2 exhibit unusual canted antiferromagnetic behavior with spin-glass-like relaxation, with blocking temperatures that are fairly high, 20 K (1) and 10 K (2), for cobalt materials. The relationship between the metal clusters and linkers has been studied, in which the size and rotational degrees of freedom of the ligands are found to control the topology, gas sorption, and magnetic properties.

17.
Inorg Chem ; 54(4): 1185-7, 2015 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-25646642

RESUMEN

Phosphonate monoesters are atypical linkers for metal-organic frameworks, but they offer potentially added versatility. In this work, a bulky isopropyl ester is used to direct the topology of a copper(II) network from a dense to an open framework, CALF-30. CALF-30 shows no adsorption of N2 or CH4 however, using CO2 sorption, CALF-30 was found to have a Langmuir surface area of over 300 m(2)/g and to be stable to conditions of 90% relative humidity at 353 K owing to kinetic shielding of the framework by the phosphonate ester.

18.
Fish Shellfish Immunol ; 41(2): 402-6, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25266890

RESUMEN

This study was conducted to evaluate the effects of laminarin on the growth performance, immunological and biochemical parameters, as well as immune related genes expression in the grouper, Epinephelus coioides. One hundred and eight fish were randomly divided into four groups (45 groupers/group). Blank control group was fed with the basal diet, while low, medium and high doses of laminarin groups were fed with the basal diet supplemented with 0.5%, 1.0%, and 1.5% laminarin, respectively, for 48 days. The immunological and biochemical parameters in blood were investigated. The mRNA levels of IL-1ß, IL-8, and TLR2 in midgut were also evaluated by quantitative real-time PCR. Dietary laminarin supplementation significantly improved the specific growth rate and the feed efficiency ratio of the fish. The level of TP and the activity of LZM, CAT and SOD were higher than that of the control. The levels of UREA and CREA as well as the activity of ALP were lower than of the control. There was no significant difference in the levels of ALT and AST between control groups and treated groups. In addition, dietary laminarin supplementation decreased the levels of C3 and C4. The expression of immune response genes IL-1ß, IL-8, and TLR2 showed significant increases (P < 0.05) in groupers fed low dose (0.5%) and medium dose (1.0%) of laminarin compared with the blank control. These results suggest that laminarin modulates the immune response and stimulates growth of the fish.


Asunto(s)
Regulación de la Expresión Génica/inmunología , Glucanos/farmacología , Perciformes/crecimiento & desarrollo , Perciformes/inmunología , ARN Mensajero/metabolismo , Animales , Proteínas Sanguíneas/metabolismo , Catalasa/sangre , Creatinina/sangre , Citocinas/sangre , Suplementos Dietéticos , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Superóxido Dismutasa/sangre
19.
Chem Commun (Camb) ; 60(8): 935-942, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38165791

RESUMEN

The properties of functional materials based on organic π-conjugated systems are governed extensively by intermolecular interactions between π-molecules. To establish clear relationships between supramolecular structures and functional properties, it is essential to attain structurally well-defined π-stacks, particularly in solution, as this enables the collection of valuable spectroscopic data. However, precise control and fine-tuning of π-stacks pose significant challenges due to the weak and bidirectional nature of π-π stacking interactions. This article introduces the concept of "frustrated π-stacking," strategically balancing attractive (π-π interaction) and repulsive (steric hindrance) forces in self-assembly to exert control over the sizes, sequences of π-stacks, and slip-stacked structures. These research efforts contribute to a deeper understanding of the correlation between π-stacks and their properties, thereby providing useful insights for the development of molecular materials with the desired performance.

20.
ChemSusChem ; 17(8): e202301619, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38123530

RESUMEN

In this work, density functional theory (DFT) calculations were conducted to investigate a series of transition metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ru, Rh, Pd, Ag, Hf, Ta, Os, Ir, and Pt) as single-atom components introduced into Ti-BPDC (BPDC=2,2'-bipyridine-5,5'-dicarboxylic acid) as catalysts (M/Ti-BPDC) for the photocatalytic reduction of CO2. The results show that Fe/Ti-BPDC is the most active candidate for CO2 reduction to HCOOH due to its small limiting potential (-0.40 V). Ag, Cr, Mn, Ru, Zr, Nb, Rh, and Cu modified Ti-BPDC are also active to HCOOH since their limiting potentials are moderate although the reaction mechanisms are different across these materials. Most of the studied catalysts show poor activity and selectivity to CO product because the stability of *COOH/*OCOH intermediates is significantly weaker than *OCHO/*HCOO species. The moderate binding strength of *CO on Pd/Ti-BPDC is responsible for its superior catalytic activity toward CH3OH generation. Electronic structural analysis was performed to uncover the origin of the activity trend for CO2 reduction to different products on M/Ti-BPDC. The calculation results indicate that the activity and selectivity of CO2 photoreduction can be effectively tuned by designing single-atom metal-based MOF catalysts.

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