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1.
Int J Mol Sci ; 22(9)2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33946609

RESUMO

Hydrogen-bonded organic frameworks (HOFs) are the focus of intense scientific research due their potential applications in science and technology. Here, we report on the synthesis, characterization, and photobehavior of a new HOF (T12F-1(124TCB)) based on a dehydrobenzoannulene derivative containing fluorine atoms (T12F-COOH). This HOF exhibits a 2D porous sheet, which is hexagonally networked via H-bonds between the carboxylic groups, and has an interlayers distance (4.3 Å) that is longer than that of a typical π-π interaction. The presence of the fluorine atoms in the DBA molecular units largely increases the emission quantum yield in DMF (0.33, T12F-COOH) when compared to the parent compound (0.02, T12-COOH). The time-resolved dynamics of T12F-COOH in DMF is governed by the emission from a locally excited state (S1, ~ 0.4 ns), a charge-transfer state (S1(CT), ~ 2 ns), and a room temperature emissive triplet state (T1, ~ 20 ns), in addition to a non-emissive triplet structure with a charge-transfer character (T1(CT), τ = 0.75 µs). We also report on the results using T12F-ester. Interestingly, FLIM experiments on single crystals unravel that the emission lifetimes of the crystalline HOF are almost twice those of the amorphous ones or the solid T12F-ester sample. This shows the relevance of the H-bonds in the photodynamics of the HOF and provides a strong basis for further development and study of HOFs based on DBAs for potential applications in photonics.


Assuntos
Alcinos/química , Flúor/química , Compostos Policíclicos/química , Alcinos/síntese química , Técnicas de Química Sintética , Cristalografia por Raios X , Ligação de Hidrogênio , Modelos Moleculares , Processos Fotoquímicos , Compostos Policíclicos/síntese química
2.
J Environ Sci (China) ; 104: 317-325, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33985735

RESUMO

The graphic carbon nitride/polyaniline (g-C3N4/PANI) hybrid composites were successfully synthesized by a facile in situ polymerization process under ice water bath. The photocatalytic activities of the g-C3N4/PANI composites were evaluated by using oxytetracycline (OTC) as model pollutants. The optimal g-C3N4/PANI composite (5%PANI: the g-C3N4/PANI hybrid with 5 wt.% of PANI) showed an enhancement degradation rate of 5-fold compared to that of conventional g-C3N4 under simulated-sunlight irradiation. In addition, the 5%PANI demonstrate significantly photocatalytic evolution H2 rate (163.2 µmol/(g⋅hr)) under the visible light irradiation. Furthermore, based on the results of optical performance and electrochemical testing, a possible mechanism was proposed, indicating that the incorporation of PANI into the traditional g-C3N4 can effectively tune the electronic structures, improve the photo-generated electrons-holes separation and enhance extensive absorption of visible light. Such a g-C3N4/PANI hybrid nanocomposites could be envisaged to possess great potentials in practical wastewater treatment and water splitting.


Assuntos
Luz , Processos Fotoquímicos , Compostos de Anilina , Catálise
3.
Int J Mol Sci ; 22(7)2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33805370

RESUMO

Retinal lipofuscin which accumulates with age in the retinal pigment epithelium (RPE) is subjected to daily exposures to high fluxes of visible light and exhibits potent photosensitising properties; however, the molecules responsible for its photoreactivity remain unknown. Here, we demonstrate that autooxidation of docosahexaenoate (DHE) leads to the formation of products absorbing, in addition to UVB and UVA light, also visible light. The products of DHE oxidation exhibit potent photosensitising properties similar to photosensitising properties of lipofuscin, including generation of an excited triplet state with similar characteristics as the lipofuscin triplet state, and photosensitised formation of singlet oxygen and superoxide. The quantum yields of singlet oxygen and superoxide generation by oxidised DHE photoexcited with visible light are 2.4- and 3.6-fold higher, respectively, than for lipofuscin, which is consistent with the fact that lipofuscin contains some chromophores which do contribute to the absorption of light but not so much to its photosensitising properties. Importantly, the wavelength dependence of photooxidation induced by DHE oxidation products normalised to equal numbers of incident photons is also similar to that of lipofuscin-it steeply increases with decreasing wavelength. Altogether, our results demonstrate that products of DHE oxidation include potent photosensitiser(s) which are likely to contribute to lipofuscin photoreactivity.


Assuntos
Ácidos Docosa-Hexaenoicos/química , Luz , Lipofuscina/química , Retina/metabolismo , Humanos , Oxirredução , Processos Fotoquímicos , Oxigênio Singlete/química , Superóxidos/química
4.
Molecules ; 26(7)2021 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-33916520

RESUMO

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and capping agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders' antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity.


Assuntos
Antibacterianos/farmacologia , Nanopartículas Metálicas/química , Saponaria/química , Óxido de Zinco/farmacologia , Antibacterianos/síntese química , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Catálise , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Química Verde , Humanos , Luz , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Micro-Ondas , Processos Fotoquímicos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Óxido de Zinco/química
5.
Int J Mol Sci ; 22(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806280

RESUMO

Amphiphilic diisobutylene/maleic acid (DIBMA) copolymers extract lipid-encased membrane proteins from lipid bilayers in a detergent-free manner, yielding nanosized, discoidal DIBMA lipid particles (DIBMALPs). Depending on the DIBMA/lipid ratio, the size of DIBMALPs can be broadly varied which makes them suitable for the incorporation of proteins of different sizes. Here, we examine the influence of the DIBMALP sizes and the presence of protein on the dynamics of encased lipids. As shown by a set of biophysical methods, the stability of DIBMALPs remains unaffected at different DIBMA/lipid ratios. Coarse-grained molecular dynamics simulations confirm the formation of viable DIBMALPs with an overall size of up to 35 nm. Electron paramagnetic resonance spectroscopy of nitroxides located at the 5th, 12th or 16th carbon atom positions in phosphatidylcholine-based spin labels reveals that the dynamics of enclosed lipids are not altered by the DIBMALP size. The presence of the membrane protein sensory rhodopsin II from Natronomonas pharaonis (NpSRII) results in a slight increase in the lipid dynamics compared to empty DIBMALPs. The light-induced photocycle shows full functionality of DIBMALPs-embedded NpSRII and a significant effect of the protein-to-lipid ratio during preparation on the NpSRII dynamics. This study indicates a possible expansion of the applicability of the DIBMALP technology on studies of membrane protein-protein interaction and oligomerization in a constraining environment.


Assuntos
Halorrodopsinas/química , Bicamadas Lipídicas/química , Rodopsinas Sensoriais/química , Alcenos/química , Fenômenos Biofísicos , Dimiristoilfosfatidilcolina/química , Espectroscopia de Ressonância de Spin Eletrônica , Halobacteriaceae/química , Halobacteriaceae/efeitos da radiação , Halorrodopsinas/efeitos da radiação , Maleatos/química , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Simulação de Dinâmica Molecular , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Processos Fotoquímicos , Rodopsinas Sensoriais/efeitos da radiação , Marcadores de Spin
6.
Food Chem ; 356: 129641, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33819786

RESUMO

Phytochemicals usually mix with food proteins in our regular diet. Unexpected interactions may lead to changes in bioaccessibility, bioactivity, and bioavailability of phytochemicals. However, our understanding of these interactions between phytochemical and food proteins is limited because of the experimental restrictions. Here, we used pulse-proteolysis to conduct the unfolding equilibrium and dose-dependent experiments on the food proteins for the first time. The interaction between epigallocatechin gallate (EGCG) and caseins was identified in the complicated food matrix, whole milk. Another food proteome, soymilk, was also optimized for identifying the binding targets of EGCG and caffeine. Among the identified interactions, the mixing of milk with coffee generates the most prominent masking effect of 46.61 ± 3.86% relative to the calculated antioxidant capacity. Our results demonstrated that pulse proteolysis is applicable for identifying the interactions between phytochemicals and proteins in the complicated food matrix.


Assuntos
Caseínas/química , Compostos Fitoquímicos/química , Animais , Antioxidantes/química , Cafeína/química , Catequina/análogos & derivados , Catequina/química , Café/química , Leite/química , Processos Fotoquímicos , Leite de Soja/química
7.
Molecules ; 26(5)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800455

RESUMO

The thin film of N-doped ZnO/CNT nanocomposite was successfully fabricated on soda lime glass substrate by a simple sol-gel drop-coating method. The structural, morphological, chemical, and optical properties of as prepared samples were characterized by a variety of tools such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared spectroscopy (FT-IR), and UV-visible spectroscopy. The hexagonal crystalline structure was confirmed from XRD measurement without any other impurity phase detection in samples. The N-doped ZnO/CNT composite showed excellent photo-catalytic activity towards cationic methylene blue (MB) dye degradation with 100% removal rate under UV light irradiation as compared to N-doped ZnO (65%) and pure ZnO (47.36%). The convincing performance has also been observed for the case of visible light irradiation. The enhancement of that photocatalytic activity might be due to narrowing the band gap as well as the reduction of electron-hole pair recombination in ZnO matrix with the incorporation of dopant nitrogen and CNT. It is assumed from the obtained results that N-doped ZnO/CNT nanocomposite thin film can be employed as an economically achievable and ecofriendly method to degrade dye with UV and visible light irradiation. Additionally, density functional theory (DFT) calculations were applied to explore the effect of N-doping on electronic structure of ZnO. The computational study has supported the experimental results of significant band gap contraction, which leads to the maximum absorption towards higher wavelength and no appreciable change of lattice parameters after doping. A conceivable photocatalytic mechanism of N-doped ZnO/CNT nanocomposite has been proposed as well.


Assuntos
Nanocompostos/química , Nitrogênio/química , Óxido de Zinco/química , Catálise , Contaminação de Medicamentos , Luz , Microscopia Eletrônica de Varredura/métodos , Processos Fotoquímicos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Raios Ultravioleta , Difração de Raios X/métodos
8.
Nat Commun ; 12(1): 2344, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33879794

RESUMO

Direct determination of RNA structures and interactions in living cells is critical for understanding their functions in normal physiology and disease states. Here, we present PARIS2, a dramatically improved method for RNA duplex determination in vivo with >4000-fold higher efficiency than previous methods. PARIS2 captures ribosome binding sites on mRNAs, reporting translation status on a transcriptome scale. Applying PARIS2 to the U8 snoRNA mutated in the neurological disorder LCC, we discover a network of dynamic RNA structures and interactions which are destabilized by patient mutations. We report the first whole genome structure of enterovirus D68, an RNA virus that causes polio-like symptoms, revealing highly dynamic conformations altered by antiviral drugs and different pathogenic strains. We also discover a replication-associated asymmetry on the (+) and (-) strands of the viral genome. This study establishes a powerful technology for efficient interrogation of the RNA structurome and interactome in human diseases.


Assuntos
Doenças Transmissíveis/genética , Doenças Transmissíveis/metabolismo , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/metabolismo , Fotoquímica/métodos , RNA/química , RNA/metabolismo , Calcinose/genética , Calcinose/metabolismo , Cistos do Sistema Nervoso Central/genética , Cistos do Sistema Nervoso Central/metabolismo , Reagentes para Ligações Cruzadas , Enterovirus Humano D/genética , Furocumarinas , Genoma Viral , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Modelos Moleculares , Mutação , Conformação de Ácido Nucleico , Processos Fotoquímicos , RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Nucleolar Pequeno/química , RNA Nucleolar Pequeno/genética , RNA Nucleolar Pequeno/metabolismo , RNA Viral/química , RNA Viral/genética
9.
Molecules ; 26(5)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33669144

RESUMO

A broadband visible light-absorbing [70]fullerene-BODIPY-triphenylamine triad (C70-B-T) has been synthesized and applied as a heavy atom-free organic triplet photosensitizer for photooxidation. By attaching two triphenylmethyl amine units (TPAs) to the π-core of BODIPY via ethynyl linkers, the absorption range of the antenna is extended to 700 nm with a peak at 600 nm. Thus, the absorption spectrum of C70-B-T almost covers the entire UV-visible region (270-700 nm). The photophysical processes are investigated by means of steady-state and transient spectroscopies. Upon photoexcitation at 339 nm, an efficient energy transfer (ET) from TPA to BODIPY occurs both in C70-B-T and B-T, resulting in the appearance of the BODIPY emission at 664 nm. Direct or indirect (via ET) excitation of the BODIPY-part of C70-B-T is followed by photoinduced ET from the antenna to C70, thus the singlet excited state of C70 (1C70*) is populated. Subsequently, the triplet excited state of C70 (3C70*) is produced via the intrinsic intersystem crossing of C70. The photooxidation ability of C70-B-T was studied using 1,5-dihydroxy naphthalene (DHN) as a chemical sensor. The photooxidation efficiency of C70-B-T is higher than that of the individual components of C70-1 and B-T, and even higher than that of methylene blue (MB). The photooxidation rate constant of C70-B-T is 1.47 and 1.51 times as that of C70-1 and MB, respectively. The results indicate that the C70-antenna systems can be used as another structure motif for a heavy atom-free organic triplet photosensitizer.


Assuntos
Compostos de Anilina/química , Compostos de Boro/química , Fulerenos/química , Luz , Fármacos Fotossensibilizantes/química , Estrutura Molecular , Oxirredução , Processos Fotoquímicos , Fármacos Fotossensibilizantes/síntese química
10.
Int J Mol Sci ; 22(4)2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33671749

RESUMO

(1) Background: Environmental contamination with antibiotics is particularly serious because the usual methods used in wastewater treatment plants turn out to be insufficient or ineffective. An interesting idea is to support natural biodegradation processes with physicochemical methods as well as with bioaugmentation with efficient microbial degraders. Hence, the aim of our study is evaluation of the effectiveness of different methods of nitrofurazone (NFZ) degradation: photolysis and photodegradation in the presence of two photocatalysts, the commercial TiO2-P25 and a self-obtained Fe3O4@SiO2/TiO2 magnetic photocatalyst. (2) Methods: The chemical nature of the photocatalysis products was investigated using a spectrometric method, and then, they were subjected to biodegradation using the strain Achromobacter xylosoxidans NFZ2. Additionally, the effects of the photodegradation products on bacterial cell surface properties and membranes were studied. (3) Results: Photocatalysis with TiO2-P25 allowed reduction of NFZ by over 90%, demonstrating that this method is twice as effective as photolysis alone. Moreover, the bacterial strain used proved to be effective in the removal of NFZ, as well as its intermediates. (4) Conclusions: The results indicated that photocatalysis alone or coupled with biodegradation with the strain A. xylosoxidans NFZ2 leads to efficient degradation and almost complete mineralization of NFZ.


Assuntos
Achromobacter denitrificans/metabolismo , Nitrofurazona/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Achromobacter denitrificans/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Biodegradação Ambiental , Catálise , Nitrofurazona/química , Nitrofurazona/toxicidade , Processos Fotoquímicos , Fotólise , Dióxido de Silício/química , Espectrofotometria Infravermelho , Titânio/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
11.
Environ Sci Technol ; 55(8): 4974-4983, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33724011

RESUMO

The direct and indirect photochemical degradation of rotenone (ROT) and deguelin (DEG), the primary reduced nicotinamide adenine dinucleotide-inhibiting rotenoid components of the piscicide CFT Legumine, were investigated under simulated sunlight conditions relevant to their dissipation from high-latitude surface waters. Photochemical degradation dominated the elimination of ROT and DEG from surface waters with half-lives ranging from 1.17 to 2.32 and 4.18 to 20.12 h for DEG and ROT, respectively, when the rotenoids were applied in the formulation CFT Legumine. We assessed enhanced degradation processes using argon-purged and cesium chloride-amended water, which demonstrated the rotenoids to rapidly decompose from excited triplet states. We further assessed the influence of reactive oxygen species by hydroxyl radical quenching and thermal generation of singlet oxygen. The studied reactive oxygen species did not significantly contribute; however, alcohols such as isopropanol may inhibit degradation by quenching ROT excited states or preventing intersystem crossing. Finally, we compared photochemical degradation in water collected from Hope Lake, Alaska, to a solution of Suwanee River fulvic acids, which demonstrated that dissolved organic matter (DOM) quality is a major factor that modulates ROT attenuation through a combination of shielding (light attenuation) and excited-state quenching mechanisms and is temperature-dependent. Molecular-level characterizations of DOM may help account for the site-specific degradation of these rotenoids in the environment.


Assuntos
Lagos , Poluentes Químicos da Água , Alaska , Radical Hidroxila , Processos Fotoquímicos , Fotólise , Rotenona/análogos & derivados
12.
Water Sci Technol ; 83(5): 1217-1229, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33724948

RESUMO

The ultraviolet photochemical degradation process is widely applied in wastewater treatment due to its low cost, high efficiency and sustainability. In this study, a novel rotating flow reactor was developed for UV-initiated photochemical reactions. The reactor was run in a continuous flow mode, and the tangential installation of the inlet and outlet on the annular reactor improved reaction rates. Numerical modelling, which combined solute transport, radiation transfer and photochemical kinetic degradation processes, was conducted to evaluate improvement compared to current reactor designs. Methylene Blue (MB) decomposition efficiency from the modelling results and the experimental data agreed well with each other. The model results showed that a rotational motion of fluid was well developed inside the designed reactor for a wide range of inflow rates; the generation of ·OH radicals significantly depended on UV irradiation dose, and thus the degradation ratio of MB showed a strong correlation with the UV irradiation distribution. In addition, the comprehensive numerical modelling showed promising potential for the simulation of UV/H2O2 processes in rotating flow reactors.


Assuntos
Peróxido de Hidrogênio , Purificação da Água , Cinética , Processos Fotoquímicos , Raios Ultravioleta
13.
Photochem Photobiol Sci ; 20(1): 183-188, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33721239

RESUMO

A hypothesis is proposed to explain the increased detrimental effect of COVID-19 for Black, Asian and Minority Ethnic (BAME) men and women compared to Caucasian individuals. This is based on the differing photochemistry of phaeomelanin in fair skin and eumelanin in dark/black skin. It is suggested that a range of reactive oxygen species, including, singlet oxygen and the superoxide radical anion, derived via direct photolysis of phaeomelanin, may escape the melanocyte and cause subsequent damage to the SARS-CoV-2 virus. It is further suggested that (large) carbon and sulphur peroxy radicals, from oxygen addition to radicals formed by carbon-sulphur bond cleavage, may assist via damage to the cell membranes. It is also speculated that light absorption by phaeomelanin and the subsequent C-S bond cleavage, leads to release of pre-absorbed reactive oxygen species, such as singlet oxygen and free radicals, which may also contribute to an enhanced protective effect for fair-skinned people.


Assuntos
COVID-19/patologia , Grupos Étnicos , Processos Fotoquímicos , COVID-19/etnologia , COVID-19/virologia , Carbono/química , Feminino , Radicais Livres/química , Humanos , Luz , Masculino , Melaninas/química , Fotólise , SARS-CoV-2/isolamento & purificação , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo , Pele/metabolismo , Enxofre/química , Superóxidos/química , Superóxidos/metabolismo
14.
Food Chem ; 351: 129362, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-33647698

RESUMO

A ligand film with citric acid (CA) on the surface as a biochelator was prepared via photografting. Polypropylene film was photochemically brushed by immobilizing glycidyl methacrylate onto the film surface (PP-g-GMA) in the presence of benzophenone. The ligand film (PP-g-GMA-g-CA) was developed via a ring-opening reaction between PP-g-GMA and CA. The chemical structure was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Microstructure and grafting morphology were observed using scanning electron microscopy and atomic force microscopy, and brushed-like configuration and porous surface morphology were described. A large amount of carboxylic acid (215 ± 11 nm) was detected on the surface of PP-g-GMA-g-CA and afforded chelation of Fe3+ (215 ± 11 nm). This ligand film exhibited chelating activity in vitamin C and virgin olive oil (p < 0.05), which extended the shelf-life of these foods. Moreover, overall migration analysis demonstrated that it can be considered as a non-migratory antioxidant.


Assuntos
Antioxidantes/química , Quelantes/química , Processos Fotoquímicos , Polipropilenos/química , Ácido Ascórbico/química , Compostos de Epóxi/química , Metacrilatos/química
15.
Nat Plants ; 7(3): 268-276, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33686224

RESUMO

Enzymatic photocatalysis is seldom used in biology. Photocatalysis by light-dependent protochlorophyllide oxidoreductase (LPOR)-one of only a few natural light-dependent enzymes-is an exception, and is responsible for the conversion of protochlorophyllide to chlorophyllide in chlorophyll biosynthesis. Photocatalysis by LPOR not only regulates the biosynthesis of the most abundant pigment on Earth but it is also a 'master switch' in photomorphogenesis in early plant development. Following illumination, LPOR promotes chlorophyll production, plastid membranes are transformed and the photosynthetic apparatus is established. Given these remarkable, light-induced pigment and morphological changes, the LPOR-catalysed reaction has been extensively studied from catalytic, physiological and plant development perspectives, highlighting vital, and multiple, cellular roles of this intriguing enzyme. Here, we offer a perspective in which the link between LPOR photocatalysis and plant photomorphogenesis is explored. Notable breakthroughs in LPOR structural biology have uncovered the structural-mechanistic basis of photocatalysis. These studies have clarified how photon absorption by the pigment protochlorophyllide-bound in a ternary LPOR-protochlorophyllide-NADPH complex-triggers photocatalysis and a cascade of complex molecular and cellular events that lead to plant morphological changes. Photocatalysis is therefore the master switch responsible for early-stage plant development and ultimately life on Earth.


Assuntos
Oxirredutases atuantes sobre Doadores de Grupo CH-CH/fisiologia , Processos Fotoquímicos , Desenvolvimento Vegetal , Proteínas de Plantas/fisiologia , Catálise , Luz , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/química , Proteínas de Plantas/química , Plantas/enzimologia , Relação Estrutura-Atividade
16.
Molecules ; 26(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668087

RESUMO

Stereolithography is a useful additive manufacturing technique for the production of scaffolds for tissue engineering. Here we present a tuneable, easy-to-manufacture, photocurable resin for use in stereolithography, based on the widely used biomaterial, poly(caprolactone) (PCL). PCL triol was methacrylated to varying degrees and mixed with photoinitiator to produce a photocurable prepolymer resin, which cured under UV light to produce a cytocompatible material. This study demonstrates that poly(caprolactone) methacrylate (PCLMA) can be produced with a range of mechanical properties and degradation rates. By increasing the degree of methacrylation (DM) of the prepolymer, the Young's modulus of the crosslinked PCLMA could be varied from 0.12-3.51 MPa. The accelerated degradation rate was also reduced from complete degradation in 17 days to non-significant degradation in 21 days. The additive manufacturing capabilities of the resin were demonstrated by the production of a variety of different 3D structures using micro-stereolithography. Here, ß-carotene was used as a novel, cytocompatible photoabsorber and enabled the production of complex geometries by giving control over cure depth. The PCLMA presented here offers an attractive, tuneable biomaterial for the production of tissue engineering scaffolds for a wide range of applications.


Assuntos
Materiais Biocompatíveis/química , Poliésteres/química , Resinas Sintéticas/química , Estereolitografia , Engenharia Tecidual , Tecidos Suporte/química , Materiais Biocompatíveis/síntese química , Estrutura Molecular , Processos Fotoquímicos , Poliésteres/síntese química , Resinas Sintéticas/síntese química , beta Caroteno/química
17.
Molecules ; 26(4)2021 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-33669994

RESUMO

In the present work, shape tailored Cu2O microparticles were synthesized by changing the nature of the reducing agent and studied subsequently. d-(+)-glucose, d-(+)-fructose, d-(+)xylose, d-(+)-galactose, and d-(+)-arabinose were chosen as reducing agents due to their different reducing abilities. The morpho-structural characteristics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS), while their photocatalytic activity was evaluated by methyl orange degradation under visible light (120 min). The results show that the number of carbon atoms in the sugars affect the morphology and particle size (from 250 nm to 1.2 µm), and differences in their degree of crystallinity and photocatalytic activity were also found. The highest activity was observed when glucose was used as the reducing agent.


Assuntos
Cobre/química , Luz , Substâncias Redutoras/química , Açúcares/química , Catálise , Tamanho da Partícula , Processos Fotoquímicos , Propriedades de Superfície
18.
J Environ Sci (China) ; 102: 185-197, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33637243

RESUMO

Understanding the formation mechanisms of secondary air pollution is very important for the formulation of air pollution control countermeasures in China. Thus, a large-scale outdoor atmospheric simulation smog chamber was constructed at Chinese Research Academy of Environmental Sciences (the CRAES Chamber), which was designed for simulating the atmospheric photochemical processes under the conditions close to the real atmospheric environment. The chamber consisted of a 56-m3 fluorinated ethylene propylene (FEP) Teflon film reactor, an electrically-driven stainless steel alloy shield, an auxiliary system, and multiple detection instrumentations. By performing a series of characterization experiments, we obtained basic parameters of the CRAES chamber, such as the mixing ability, the background reactivity, and the wall loss rates of gaseous compounds (propene, NO, NO2, ozone) and aerosols (ammonium sulfate). Oxidation experiments were also performed to study the formation of ozone and secondary organic aerosol (SOA), including α-pinene ozonolysis, propene and 1,3,5-trimethylbenzene photooxidation. Temperature and seed effects on the vapor wall loss and SOA yields were obtained in this work: higher temperature and the presence of seed could reduce the vapor wall loss; SOA yield was found to depend inversely on temperature, and the presence of seed could increase SOA yield. The seed was suggested to be used in the chamber to reduce the interaction between the gas phase and chamber walls. The results above showed that the CRAES chamber was reliable and could meet the demands for investigating tropospheric chemistry.


Assuntos
Poluentes Atmosféricos , Smog , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Processos Fotoquímicos , Smog/análise
19.
Food Chem ; 350: 129222, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33607411

RESUMO

The reaction pathways were investigated by which a fungoid chitosan (CsG) may protect against photooxidative decay of model solutions and a sulphite-free white wine. Samples containing CsG were dark incubated for 2 days before exposure to fluorescent lighting for up to 21 days in the presence of wine like (+)-catechin and/or iron doses. In both systems CsG at winemaking doses significantly reduced the photoproduction of acetaldehyde and, to a better extent, glyoxylic acid, two key reactive aldehydes implicated in wine oxidative spoilage. After 21 days, CsG was two-fold more effective than sulphur dioxide in preventing glyoxylic acid formation and minimizing the browning of white wine. Among the antioxidant mechanisms involved in CsG protective effect, iron chelation, and hydrogen peroxide quenching were demonstrated. Besides, the previously unreported tartrate displacement from the [iron(III)-tartrate] complex was revealed as an additional inhibitory mechanism of CsG under photo-Fenton oxidation conditions.


Assuntos
Aldeídos/química , Quitosana/química , Processos Fotoquímicos , Vinho/análise , Antioxidantes/química , Catequina/química , Glioxilatos/química , Oxirredução , Dióxido de Enxofre/química , Tartaratos/química
20.
ACS Appl Mater Interfaces ; 13(6): 7037-7050, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33517661

RESUMO

As the essential foundation of bioprinting technology, cell-laden bio-ink is confronted with the inevitable contradiction between printability and bioactivity. For example, type I collagen has been widely applied for its excellent biocompatibility; however, its relatively low self-assembly speed restricts the performance in high-precision bioprinting of cell-laden structures. In this study, we synthesize norbornene-functionalized neutral soluble collagen (NorCol) by the reaction of acid-soluble collagen (Col) and carbic anhydride in the aqueous phase. NorCol retains collagen triple-helical conformation and can be quickly orthogonally cross-linked to build a cell-laden hydrogel via a cell-friendly thiol-ene photoclick reaction. Moreover, the additional carboxyl groups produced in the reaction of carbic anhydride and collagen obviously improve the solubility of NorCol in neutral buffer and miscibility of NorCol with other polymers such as alginate and gelatin. It enables hybrid bio-ink to respond to multiple stimuli, resulting in continuous cross-linked NorCol networks in hybrid hydrogels. For the first time, the collagen with a triple helix structure and gelatin can be mixed and printed, keeping the integrity of the printed construct after gelatin's dissolution. The molecular interaction among giant collagen molecules allows NorCol hydrogel formation at a low concentration, which leads to excellent cell spreading, migration, and proliferation. These properties give NorCol flexible formability and excellent biocompatibility in temperature-, ion-, and photo-based bioprinting. We speculate that NorCol is a promising bio-ink for emerging demands in tissue engineering, regenerative medicine, and personalized therapeutics.


Assuntos
Materiais Biocompatíveis/química , Bioimpressão , Colágeno/química , Reagentes para Ligações Cruzadas/química , Norbornanos/química , Compostos de Sulfidrila/química , Animais , Materiais Biocompatíveis/síntese química , Adesão Celular , Linhagem Celular , Movimento Celular , Proliferação de Células , Colágeno/síntese química , Reagentes para Ligações Cruzadas/síntese química , Humanos , Tamanho da Partícula , Processos Fotoquímicos , Ratos , Ratos Sprague-Dawley , Propriedades de Superfície
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