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1.
Cell Mol Biol (Noisy-le-grand) ; 70(2): 51-61, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38430038

RESUMO

Anoikis emerges when a cell finds itself extricated from the appropriate extracellular matrix, leading to an interruption in integrin ligation and thus triggering programmed cellular demise. The cardinal role of Anoikis in the realms of tumor invasion and metastasis is undeniable, although our grasp on its precise influence within the convoluted landscape of cancer biology remains somewhat circumscribed. Notably, both the immune milieu of the tumor and its inherent aggression are correlated with the fluctuating variables of Anoikis. We conducted a thorough evaluation of the genes associated with anoikis and studied the regulatory patterns of these genes as well as the prognostic impact of anoikis in 33 different types of tumors. We provided functional annotations for the regulatory patterns linked to Anoikis. Additionally, we described the associations between immunological factors and genes associated with Anoikis. By applying gene set variation analysis (GSVA), we utilized the inherent abilities of 34 basic genes to calculate the Anoikis index. The Anoikis index is closely related to prognosis, immune microenvironment, immunotherapy, and other aspects. Our functional research revealed a correlation between immune cell infiltration, EMT, and a regulatory gene that is synonymous with adverse survival outcomes. In addition, our observations revealed a direct relationship between the expression of CEACAM5 and CEACAM6,the amplification of epithelial mesenchymal transition (EMT) phenomenon, and a decrease in survival outcomes.The potential therapeutic utility of anoikis-related genes was highlighted by the possible links between TME, clinical samples, genetic mutations, drug resistance, and immunotherapy.


Assuntos
Anoikis , Neoplasias , Humanos , Anoikis/genética , Linhagem Celular Tumoral , Neoplasias/genética
2.
Ecotoxicol Environ Saf ; 277: 116380, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38677068

RESUMO

The interaction between microplastics (MPs) and cadmium (Cd) poses a threat to agricultural soil environments, and their effects on plant growth and rhizosphere microbial community functions are not yet clear. In this study, energy sorghum was used as a test plant to investigate the effects of two types of MPs, polystyrene (PS) and polyethylene (PE), at different particle sizes (13 µm, 550 µm) and concentrations (0.1%, 1% w/w), and Cd, as well as their interactions, on the growth of sorghum in a soil-cultivation pot experiment. The results showed that the combined effects of MP and Cd pollution on the dry weight and Cd accumulation rate in sorghum varied depending on the type, concentration, and particle size of the MPs, with an overall trend of increasing stress from combined pollution with increasing Cd content and accumulation. High-throughput sequencing analysis revealed that combined MP and Cd pollution increased bacterial diversity, and the most significant increase was observed in the abundance-based coverage estimator (ACE), Shannon, and Sobs indices in the 13 µm 1% PS+Cd treatment group. Metagenomic analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed that 19 groups of metabolic pathways, including microbial metabolism and methane metabolism, differed significantly under combined MP and Cd pollution. Hierarchical clustering results indicated that Cd treatment and combined MP and Cd treatment affected the abundances of sorghum rhizosphere soil nitrogen (N) and phosphorus (P) cycling genes and that the type of MP present was an important factor affecting N and P cycling genes. The results of this study provide a basis for exploring the toxic effects of combined MP and Cd pollution and for conducting soil environmental risk assessments.


Assuntos
Cádmio , Microplásticos , Rizosfera , Microbiologia do Solo , Poluentes do Solo , Sorghum , Sorghum/efeitos dos fármacos , Sorghum/microbiologia , Cádmio/toxicidade , Poluentes do Solo/toxicidade , Microplásticos/toxicidade , Solo/química , Tamanho da Partícula , Bactérias/efeitos dos fármacos
3.
Angew Chem Int Ed Engl ; 63(27): e202406524, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38702292

RESUMO

Circularly polarized luminescence (CPL)-active materials are increasingly recognized for their potential applications such as 3D imaging, data storage, and optoelectronic devices. Typically, CPL materials have required high-energy (HE) photons for excitation to emit low-energy (LE) circularly polarized light, a process known as downshifting CPL (DSCPL). However, the emergence of upconverted CPL (UCCPL), where the absorption of multi LE photons results in the emission of a single HE photon with circular polarization, has recently attracted considerable attention. This minireview highlights the intricate relationship between upconversion and CPL phenomena. During upconversion, the dissymmetry factor (glum) value can be improved in certain systems. Additionally, the integration of both LE and HE photons in upconversion-downshifting-synergistic systems offers avenues for dual-excitation or dual-emission CPL functionalities. More in detail, the emerging UCCPL based on various photon upconversion mechanisms and their synergy with DSCPL are introduced. Additionally, several examples that demonstrate the applications of UCCPL are presented to highlight the future opportunities.

4.
Angew Chem Int Ed Engl ; 63(22): e202403898, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38497553

RESUMO

Addressing the dual enhancement of circular polarization (glum) and luminescence quantum yield (QY) in circularly polarized luminescence (CPL) systems poses a significant challenge. In this study, we present an innovative strategy utilizing the entropically driven self-assembly of amphiphilic phosphorescent platinum(II) complexes (L-Pt) with tetraethylene glycol chains, resulting in unique temperature dependencies. The entropically driven self-assembly of L-Pt leads to a synergistic improvement in phosphorescence emission efficiency (QY was amplified from 15 % at 25 °C to 53 % at 60 °C) and chirality, both in the ground state and the excited state (glum value has been magnified from 0.04×10-2 to 0.06) with increasing temperature. Notably, we observed reversible modulation of phosphorescence and chirality observed over at least 10 cycles through successive heating and cooling, highlighting the intelligent control of luminescence and chiroptical properties by regulating intermolecular interactions among neighboring L-Pt molecules. Importantly, the QY and glum of the L-Pt assembly in solid state were measured as 69 % and 0.16 respectively, representing relatively high values compared to most self-assembled CPL systems. This study marks the pioneering demonstration of dual thermo-enhancement of phosphorescence and CPL and provides valuable insights into the thermal effects on high-temperature and switchable CPL materials.

5.
Chirality ; 35(6): 346-354, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36792058

RESUMO

Circularly polarized luminescence (CPL) has been widely demonstrated that the circular polarization in excited state can be significantly amplified through the triplet-triplet annihilation-based upconversion (TTA-UC) luminescence process in various chiral nano-assemblies. However, constructing such an upconverted circularly polarized luminescence (UC-CPL) system in the aqueous phase remains a challenge. In this work, a kind of amphiphilic chiral cationic gemini surfactant is utilized to construct chiral spherical micelle in the aqueous phase, whose internal chiral cavity can provide a hydrophobic and deoxygenated environment for air-sensitive TTA-UC system. In addition, due to the co-assembly process between the emitters and chiral micelles, achiral emitters of upconversion pairs exhibit induced chiroptical properties. More importantly, the luminescence dissymmetry factor (glum ) can be amplified by one order of magnitude through TTA-UC process. This work provides an effective and useful strategy for realizing UC-CPL in aqueous phase.

6.
Cryobiology ; 112: 104555, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37385538

RESUMO

In this study, the toxicity of sucrose to Oplegnathus punctatus embryos was evaluated. Embryos at the 4-6 somite, tail-bud, heart formation, and heart-beating stages were exposed to 0, 0.5, 1,1.5, 2, 2.5, or 3 M sucrose for 1 h. Survival rates of embryos at the tail-bud, heart formation, and heart-beating stages after rehydration for 1 h were not affected by treatment with 2 M sucrose (the maximum concentration). Embryos at the tail-bud, heart formation, and heart-beating stages were exposed to 2 M sucrose for 0, 30, 60, 90, 120, 150, or 180 min. Long-term developmental indicators, including rates of survival, hatching, swimming, and malformation, were evaluated for 4 days after rehydration. Based on the survival rates 10 min after rehydration, the longest tolerance time for embryos at the three stages was 120 min. Based on long-term developmental indicators, the longest tolerance times were 60 min at the tail-bud, 60 min at the heart formation stage and 30 min at the heart beating stage. The malformation rates increased as the treatment time increased. The malformation rates were 100% when embryos were exposed to sucrose for ≥120 min. Malformation was divided into larval and embryonic abnormality. As the exposure time increased for tail-bud stage embryos, the rate of larval malformation increased. Treatment at heart formation and heart-beating stages resulted in higher rates of failure to hatch at exposure time. Based on these results, toxicity tests of non-permeable cryoprotectant in embryos requires the observation of development for at least 2 days after rehydration. Based on long-term observation, it was concluded that dehydration before freezing was not the direct cause of larvae deformity that hatched from frozen-thawing embryo. These results provide a reference for the singly use of representative non-permeable cryoprotectant sucrose.


Assuntos
Criopreservação , Sacarose , Animais , Criopreservação/métodos , Sacarose/farmacologia , Crioprotetores/toxicidade , Peixes , Embrião de Mamíferos , Larva
7.
Genomics ; 114(5): 110473, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36049667

RESUMO

The potato grouper, Epinephelus tukula, is one of the largest coral reef teleost, and it is an important germplasm resource for selection and cross breeding. Here we report a potato grouper genome assembly generated using PacBio long-read sequencing, Illumina sequencing and high-throughput chromatin conformation capture (Hi-C) technology. The genome size was 1.13 Gb, with a total of 508 contigs anchored into 24 chromosomes. The scaffold N50 was 42.65 Mb. For the genome models, our assembled genome contained 98.11% complete BUSCO with the vertebrata_odb9 database. One more copies of Gh and Hsp90b1 were identified in the E. tukula genome, which might contribute to its fast growth and high resistance to stress. In addition, 435 putative antimicrobial peptide (AMP) genes were identified in the potato grouper. This study provides a good reference for whole genome selective breeding of the potato grouper and for future development of novel marine drugs.


Assuntos
Bass , Animais , Bass/genética , Cromatina , Cromossomos/genética , Filogenia
8.
Angew Chem Int Ed Engl ; 62(50): e202315136, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-37902429

RESUMO

The helical twisting tendency of liquid crystals (LCs) is generally governed by the inherent configuration of the chiral emitter. Here, we introduce the multistage inversion of supramolecular chirality as well as circularly polarized luminescence (CPL) by manipulating the ratio of single enantiomeric emitters (R-PCP) to LC monomers (5CB). Increasing the content of R-PCP from 1 wt % to 3 wt % inverted the helix of LCs from left-handed to right-handed, accompanying a CPL sign changed from positive to negative. The biaxiality of chiral emitters, as well as the steric effect of chiral-chiral and chiral-achiral interaction, were identified as the reasons for helical sense inversion. Due to the strong helical twisting power, 4 wt % R-PCP drove the photonic band gap (PBG) of chiral LCs to match up with their emission range, leading to an inversion of the CPL again with a high dissymmetry factor (≈1.2). Directly adjusting the PBG using chiral emitters is seldom achieved in cholesteric LCs. On this basis, an achiral sensitizer PtTPBP was assembled into the helical superstructure. The generation of triplet-triplet annihilation-induced upconverted CPL from R-PCP and the downshifting CPL from PtTPBP with opposite rotation was achieved in a single chiral LC system by tuning the position of the PBG.

9.
Angew Chem Int Ed Engl ; 62(28): e202301085, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37163203

RESUMO

Although numerous chiral small molecules have been discovered and synthesized, the investigation on their enantioselective immunological effects remains limited. In this study, we designed and synthesized a pair of small molecule enantiomers (R/S-ResP) by covalently bonding two immunostimulators (resiquimod/Res) onto a planar chiral framework (paracyclophane/P). Notably, we found that S-ResP exhibits a 4.05-fold higher affinity for toll-like receptor 7 (TLR7) than R-ResP, thereby more effectively enhancing the functions of dendritic cells and macrophages in cytokine secretion and antigen internalization. Furthermore, we observed that S-ResP significantly enhances RBD antigen-induced cross-neutralization against various SARS-CoV-2 strains compared to R-ResP. These findings demonstrate the enantioselective effects of small molecules on regulating vaccine-induced immune responses and emphasize the significance of chirality in designing small molecular adjuvants.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Humanos , Estereoisomerismo , SARS-CoV-2 , Adjuvantes Imunológicos/farmacologia , Imunidade , Anticorpos Antivirais , Anticorpos Neutralizantes
10.
Angew Chem Int Ed Engl ; 61(38): e202206332, 2022 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-35751618

RESUMO

Among the enticing issues of chiral origins are: how chirality is born from the initial achiral units and the mechanisms for the transfer of chiral information. In this work, by combining a physical vortex and chiral seeds, a general process is revealed to generate chiral supramolecular polymers from achiral C3 -symmetric molecules. The symmetry-broken assemblies from the achiral molecules could work as chiral seeds to initiate the polymerization of either homologous or heterologous achiral monomers. Concomitantly, the fragmentation of the polymer caused by the vortex during the nucleation-elongation stages is shown to enlarge the domains of the chiral nuclei and then guide the polymer to grow into the predominant helicity with a high reactivity ratio. Moreover, the chiral structural information can be stored in different forms of assemblies. These new polymerization modes will provide guidance for the preparation of chiral materials.


Assuntos
Polímeros , Polimerização , Polímeros/química
11.
Angew Chem Int Ed Engl ; 61(5): e202115600, 2022 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-34881474

RESUMO

Chirality generation and transfer is not only of critical importance in resolving the origin of biological homochirality, but also is of great significance for exploring the chirality-related functionalities in nanomaterials and supramolecular systems. Although modulating the ground state chirality in chiral nanomaterials has been widely demonstrated, it remains a big challenge to steer the excited state chirality (circularly polarized luminescence, CPL). Herein, we present a kind of chiral spherical micelles constructed by chiral cationic gemini surfactants, whose surfaces and cavities could co-assemble with hydrophilic and hydrophobic emitters concurrently. Subsequently, the hydrophilic and hydrophobic emitters could be endowed with CPL activity in the aqueous phase. Additionally, the cavities of such micelles can be regarded as the powerful chiral confined space, which could effectively modulate the excited state chirality of dynamic chemical reactions, enabling color-adjustable CPL emission.

12.
Angew Chem Int Ed Engl ; 61(25): e202203938, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35441771

RESUMO

Flexible organic crystals with unique mechanical properties and excellent optical properties are of paramount significance for their wide applications in various research fields such as adaptive optics and soft robotics. However, low-temperature-resistant flexible organic crystal with circularly polarized luminescence (CPL) has never been reported. Herein, chiral organic crystals with CPL activity and low-temperature flexibility (77 K) are fabricated by the solvent diffusion method from chiral Schiff base, S(R)-4-bromo-2-(((1-phenylethyl)imino)methyl)phenol (S(R)-BPEMP). The corresponding chirooptical properties for the two enantiomeric crystals were thoroughly investigated, including the measurements of circular dichroism (CD) and CPL. To the best of our knowledge, this is the first report on low-molecular-weight flexible organic crystals with CPL activity, and we believe that the results will give a new impetus to the research of organic crystals.

13.
J Am Chem Soc ; 143(33): 13259-13265, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387996

RESUMO

Research on chiral selection and recognition not only is of fundamental importance in resolving the origin of biological homochirality, but also is instructive in the fabrication of controlled molecular organization in supramolecular systems to modulate their chirality-related functional properties. Here we report an enantioselective assembly process between a chiral energy donor and two enantiomeric energy acceptors, which further results in chirality-controlled energy transfer and enantioselective triplet-triplet annihilation upconversion (TTA-UC). It is found that the chiral energy donor Pd(II) octaethylporphyrin derivative PdOEP-LG12 (RD) can selectively coassemble with the chiral energy acceptor LGAn (RA) with the same chiral scaffold but tends to form segregation with the energy acceptor DGAn (SA) with the opposite chiral scaffold in a thermodynamic equilibrium state. Thus, the coassembly of RA/RD shows more effective triplet-triplet energy transfer (TTET) and stronger upconverted luminescence and upconverted circularly polarized luminescence in comparison to the segregation of SA/RD. The establishment of such an enantioselective TTA-UC system highlights the applications of chirality-regulated triplet fusion in optoelectronic materials.

14.
Acc Chem Res ; 53(7): 1279-1292, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32649172

RESUMO

Chiral functional materials with circularly polarized luminescence (CPL) have risen rapidly in recent years because of their fascinating characteristics and potential applications in various research fields. CPL refers to the differential spontaneous emission of left (L)- and right (R)-handed circularly polarized light upon photon or electron excitation. Generally, an outstanding CPL-active material needs to possess a high luminescence dissymmetry factor (glum) (defined as 2(IL - IR)/(IL + IR) where I is the emission intensity), which is between -2 and +2. Although the exciting development in CPL-active materials was achieved, the modulation of CPL signs is still a challenge. For small organic systems, a relatively small glum value, one of the key parameters of CPL, limits their practical applications. Searching for efficient approaches for amplifying glum is important. Therefore, over the past decades, besides optimizing the structure of small molecules, many other strategies to obtain efficient CPL-active materials have been developed. For instance, self-assembly has been well demonstrated as an effective approach to amplify the supramolecular chirality as well as the glum values. On the other hand, chiral liquid crystals (CLCs), which are capable of selective reflection of left- and right-handed circularly polarized light, also to serve as a host matrix for endowing guest emitters with CPL activity and high glum values. However, self-assembly focuses on modulating the conformation and spatial arrangement of chiral emitters. And the CPL of a luminophore-doped CLC matrix depends on the helix pitch and band gap positions. Lately, novel photophysical approaches to modulate CPL signs have gradually emerged.In this Account, we discuss the recent progress of excited-state-regulation involved CPL-active materials. The emergence, amplification, and inversion of CPL can be adjusted through regulation of the excited state of chiral emitters. For example, Förster resonance energy transfer (FRET) can amplify the glum values of chiral energy acceptors in chiral supramolecular assemblies. By combining the concepts of photon upconversion and CPL, high-energy upconverted circularly polarized emission was achieved under excitation of low-energy light, accompanied by an amplified glum. In addition, the organic systems with unpaired electrons, i.e., charge transfer (CT) system and open-shell π-radical, show favorable CPL properties, which can be flexibly tuned with an applied magnetic field. It should be noted that these photophysical process are associated with the excited state of chiral emitters. So far, while the main focus is on the regulation of the molecular and supramolecular nanostructures, direct regulation of the excited state of the chiral system will serve as a new platform to understand and regulate the CPL activity and will be helpful to develop smart chiroptical materials.

15.
Nanotechnology ; 32(47)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34252893

RESUMO

Photofluorochromic diarylethene (DAE) molecules have been widely investigated due to their excellent fatigue resistance and thermal stability. However, the poor water solubility of DAEs limits their biological applications to some extent. Herein, we reported two kinds of water-dispersible DAE nanoparticles (DAEI-NPs and DAEB-NPs), in which DAE molecules were stabilized by the amphiphilic polymer DSPE-mPEG2000 using the nanoprecipitation approach. The fabricated nanoparticles retain well-controlled luminescence and fluorescence photoswitching properties in aqueous solution, which could be reversibly switched on and off under the alternating irradiation of ultraviolet (UV) and visible light. In addition, the closed-ring isomers of DAEB-NPs performed hot-band-absorption-based photon upconversion when excited by a 593.5 nm laser. Bearing excellent photophysical properties and low cytotoxicity, DAEB-NPs were applicable for upconversion cell imaging without high-excitation power density and free from oxygen removal. Additionally, the imaging process could be switched on by regulating the photofluorochromic nanoparticles.


Assuntos
Teste de Materiais , Nanopartículas/química , Raios Ultravioleta , Células HeLa , Humanos , Microscopia de Fluorescência
16.
Respirology ; 26(12): 1131-1151, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34541740

RESUMO

Early life represents a critical period for the development and growth of the lungs. Adverse exposures in this stage may drive the development of chronic obstructive pulmonary disease (COPD). Thus, we quantitatively evaluated the impact of different early life exposures on COPD in adulthood. The PubMed, Embase and Cochrane Library electronic databases were searched for articles published from January 2001 to October 2020. A total of 30 studies (795,935 participants) met the criteria and were included in the review. We found a significant association of COPD with childhood serious respiratory infections, pneumonia or bronchitis (pooled adjusted OR [aOR], 2.23 [95% CI, 1.63-3.07]). The probability of COPD was increased 3.45-fold for children with than without asthma (pooled aOR, 3.45 [95% CI, 2.37-5.02]). In addition, the probability of COPD was associated with maternal smoking (pooled aOR, 1.42 [95% CI, 1.17-1.72]), any child maltreatment (pooled aOR, 1.30 [95% CI, 1.18-1.42]) and low birth weight (pooled aOR, 1.58 [95% CI, 1.08-2.32]) but not childhood environmental tobacco smoke exposure (pooled aOR, 1.15 [0.83-1.61]) or premature birth (pooled aOR, 1.17 [95% CI, 0.87-1.58]). Furthermore, subgroup analyses revealed that probability was increased for only women with childhood physical abuse, sexual abuse and exposure to intimate partner violence. Factors resulting in COPD in adults could trace back to early life. Childhood respiratory disease, maltreatment, maternal smoking and low birth weight increase the risk of COPD. Promising advances in prevention strategies for early life exposures could markedly decrease the risk of COPD.


Assuntos
Asma , Doença Pulmonar Obstrutiva Crônica , Infecções Respiratórias , Adulto , Asma/epidemiologia , Asma/etiologia , Criança , Feminino , Humanos , Pulmão , Gravidez , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Doença Pulmonar Obstrutiva Crônica/etiologia , Fumar/efeitos adversos
17.
Angew Chem Int Ed Engl ; 60(9): 4575-4580, 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33236479

RESUMO

A major trade-off in the field of circularly polarized luminescence (CPL) of pure organic materials is that the large luminescence dissymmetry factor (glum ) usually gives rise to the suppression of luminescence efficiency (ΦPL ). Here, a supramolecular self-assembled system, driven by arene-perfluoroarene (AP) interactions of chiral polycyclic aromatic hydrocarbons (PAHs) and octafluoronaphthalene (OFN), is reported to provide a solution to this problem. Two kinds of chiral PAHs based on pyrene and anthracene could co-assemble with OFN in hybrid solvents to form long-range-ordered AP assemblies. The detailed process of AP interaction driving self-assembly was verified by morphological measurements and fluorescence spectra. The AP assemblies exhibited chirality amplification not only in the excited state but also in the ground state. In addition, the AP assemblies showed an enhanced luminescence efficiency compared with the individual chiral PAHs due to the energy-barrier effect of OFN. The present strategy based on AP interactions could be applied to boost the development of highly efficient CPL-active materials.

18.
Angew Chem Int Ed Engl ; 60(42): 22711-22716, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34411386

RESUMO

Self-assembled chiroptical materials have attracted considerable attention due to their great applications in wide fields. During the chiral self-assembly, it remains unknown how achiral molecules can affect the assembly process and their final chiroptical performance. Herein, we report an achiral molecule directed chiral self-assembly via halogen bonds, exhibiting not only an unprecedented chiral fractal architecture but also significantly amplified circularly polarized luminescence (CPL). Two axially chiral emitters with halogen bond sites co-assemble with an achiral 1,4-diiodotetrafluorobenzene (F4 DIB) and well-ordered chiral fractal structures with asymmetry amplification are obtained. The enhancement of the dissymmetry factors of the assemblies was up to 0.051 and 0.011, which was approximately 100 folds than those of the corresponding molecules. It was found that both the design of the chiral emitter and the highly directional halogen bond played an important role in hierarchically chirality transfer from chiral emitters to the micrometer scale chiral fractal morphology and amplified dissymmetry factors. We hope that this strategy can give a further insight into the fabrication of structurally unique featured highly efficient chiroptical materials.

19.
Phys Rev Lett ; 124(8): 083901, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32167354

RESUMO

Exceptional points (EPs), branch points of complex energy surfaces at which eigenvalues and eigenvectors coalesce, are ubiquitous in non-Hermitian systems. Many novel properties and applications have been proposed around the EPs. One of the important applications is to enhance the detection sensitivity. However, due to the lack of single-handed superchiral fields, all of the proposed EP-based sensing mechanisms are only useful for the nonchiral discrimination. Here, we propose theoretically and demonstrate experimentally a new type of EP, which is called a radiation vector EP, to fulfill the homogeneous superchiral fields for chiral sensing. This type of EP is realized by suitably tuning the coupling strength and radiation losses for a pair of orthogonal polarization modes in the photonic crystal slab. Based on the unique modal-coupling property at the vector EP, we demonstrate that the uniform superchiral fields can be generated with two beams of lights illuminating the photonic crystal slab from opposite directions. Thus, the designed photonic crystal slab, which supports the vector EP, can be used to perform surface-enhanced chiral detection. Our findings provide a new strategy for ultrasensitive characterization and quantification of molecular chirality, a key aspect for various bioscience and biomedicine applications.

20.
Ecotoxicol Environ Saf ; 187: 109809, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31654861

RESUMO

A theoretical non-linear combined toxicity assessment method is proposed and evaluated using Microcystis aeruginosa as the test organism. The combined toxicity of binary heavy metals was evaluated by comparing the actual inhibitory rates shown from the experiments with the theoretically calculated inhibitory rates. It was identified that the binary mixtures of Cu2++ Cd2+, Cu2++ Cr3+ and Zn2++ Cr3+ had the synergistic effects when the combined concentrations were low, but exhibited the antagonistic effects with the higher combined concentrations. Furthermore, the toxic effect of Pb2+ was not influenced by the addition of Cu2+ when combined concentration was low, but it was enhanced by Cu2+ at the high combined concentration. The binary mixtures of Zn2++ Cd2+, Pb2++ Cr3+, Pb2++ Cd2+, Pb2++ Zn2+, and Cr3++ Cd2+ always presented antagonistic effects, while the synergistic toxicity effect on M. aeruginosa was observed for the binary mixtures of Cu2++ Zn2+ regardless of combined concentration. The proposed assessment method was also validated by the antioxidant enzyme activity, which showed synergistic or antagonistic effects under different binary mixtures of heavy metals.


Assuntos
Metais Pesados/toxicidade , Microcystis/efeitos dos fármacos , Modelos Teóricos , Antioxidantes/metabolismo , Sinergismo Farmacológico , Malondialdeído/metabolismo , Metais Pesados/química , Microcystis/enzimologia , Dinâmica não Linear , Espécies Reativas de Oxigênio/metabolismo
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