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1.
Bioresour Technol ; 397: 130489, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38403170

RESUMO

Microalgae are photosynthetic microorganisms with the potential to mitigate the atmospheric greenhouse effect by carbon fixation. However, their growth is typically limited by light availability. A wavelength converter utilizing red, blue, and green quantum dots (QDs) was developed to optimize light quality for enhancing microalgal production. The growth, lipid content, and eicosapentaenoic acid titer of Nannochloropsis increased by 11.2%, 9.5%, and 15.5% with red QDs, respectively. The biomass and triacylglycerol content of Phaeodactylum tricornutum increased by 8.6% and 35.0%, respectively. Simultaneously, biodiesel production was accelerated in Nannochloropsis (20.2%) and P. tricornutum (11.6%), and improved with increased cetane number and reduced iodine value. Furthermore, red QDs increased the growth and biomass accumulation of Nannochloropsis under low light, while green QDs shielded Nannochloropsis from photoinhibition under high light. This customizable QD-based methodology overcomes microalgal light limitations, demonstrating a universally applicable approach to improve microalgal cultivation and biochemical component production.


Assuntos
Microalgas , Pontos Quânticos , Estramenópilas , Microalgas/metabolismo , Luz , Fotossíntese , Triglicerídeos , Biomassa , Biocombustíveis
2.
Angew Chem Int Ed Engl ; 63(9): e202316698, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38169129

RESUMO

Morphological control of all-polymer blends is quintessential yet challenging in fabricating high-performance organic solar cells. Recently, solid additives (SAs) have been approved to be capable in tuning the morphology of polymer: small-molecule blends improving the performance and stability of devices. Herein, three perhalogenated thiophenes, which are 3,4-dibromo-2,5-diiodothiophene (SA-T1), 2,5-dibromo-3,4-diiodothiophene (SA-T2), and 2,3-dibromo-4,5-diiodothiophene (SA-T3), were adopted as SAs to optimize the performance of all-polymer organic solar cells (APSCs). For the blend of PM6 and PY-IT, benefitting from the intermolecular interactions between perhalogenated thiophenes and polymers, the molecular packing properties could be finely regulated after introducing these SAs. In situ UV/Vis measurement revealed that these SAs could assist morphological character evolution in the all-polymer blend, leading to their optimal morphologies. Compared to the as-cast device of PM6 : PY-IT, all SA-treated binary devices displayed enhanced power conversion efficiencies of 17.4-18.3 % with obviously elevated short-circuit current densities and fill factors. To our knowledge, the PCE of 18.3 % for SA-T1-treated binary ranks the highest among all binary APSCs to date. Meanwhile, the universality of SA-T1 in other all-polymer blends is demonstrated with unanimously improved device performance. This work provide a new pathway in realizing high-performance APSCs.

3.
Adv Sci (Weinh) ; 11(12): e2306518, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38234238

RESUMO

Colloidal semiconductor nanoplatelets (NPLs) have emerged as low-cost and free-standing alternates of traditional quantum wells. The giant heavy- and light-hole splitting in NPLs allows for efficient optical spin injection. However, the electron spin lifetimes for prototypical CdSe NPLs are within a few picoseconds, likely limited by strong electron-hole exchange in these quantum- and dielectric-confined materials. Here how this hurdle can be overcome with engineered NPL-heterostructures is demonstrated. By constructing type-I CdSe/ZnS core/shell NPLs, dielectric screening inside the core is strongly enhanced, prolonging the electron spin polarization time (τesp) to over 30 ps (or 60 ps electron spin-flip time). Alternatively, by growing type-II CdSe/CdTe core/crown NPLs to spatially separate electron and hole wavefunctions, the electron-hole exchange is strongly suppressed, resulting in τesp as long as 300 ps at room temperature. This study not only exemplifies how the well-established synthetic chemistry of colloidal heterostructures can aid in spin dynamics control but also establishes the feasibility of room-temperature coherent spin manipulation in colloidal NPLs.

4.
Adv Sci (Weinh) ; 10(33): e2300386, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37807821

RESUMO

The electronic structure of halide perovskites is central to their carrier dynamics, enabling the excellent optoelectronic performance. However, the experimentally resolved transient absorption spectra exhibit large discrepancies from the commonly computed electronic structure by density functional theory. Using pseudocubic CsPbI3 as a prototype example, here, it is unveiled with both ab initio molecular dynamics simulations and transmission electron microscopy that there exists pronounced dynamical lattice distortion in the form of disordered instantaneous octahedral tilting. Rigorous first-principles calculations reveal that the lattice distortion substantially alters the electronic band structure through renormalizing the band dispersions and the interband transition energies. Most notably, the electron and hole effective masses increase by 65% and 88%, respectively; the transition energy between the two highest valence bands decreases by about one half, agreeing remarkably well with supercontinuum transient-absorption measurements. This study further demonstrates how the resulting electronic structure modulates various aspects of the carrier dynamics such as carrier transport, hot-carrier relaxation, Auger recombination, and carrier multiplication in halide perovskites. The insights provide a pathway to engineer carrier transport and relaxation via lattice distortion, enabling the promise to achieve ultrahigh-efficiency photovoltaic devices.

5.
Heliyon ; 9(9): e19383, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37662812

RESUMO

Chronic kidney disease (CKD) is now recognized as a major public health problem in the world. The global prevalence of CKD is estimated at 13.4% (11.7-15.1%), with an estimated 490.2 to 7.083 million patients with End stage renal disease requiring renal replacement therapy. Hemodialysis is the main treatment for End stage renal disease patients because of its high safety and efficiency. The survival time of these patients was significantly prolonged, but many psychological problems followed. Depression is a type of mood disorder caused by a variety of causes, often manifested as disproportionate depression and loss of interest, sometimes accompanied by anxiety, agitation, even hallucinations, delusions and other psychotic symptoms. Depression has become the most common mental disorder in maintenance hemodialysis (MHD) patients according to the meta-analysis. In recent years, depression has seriously affected the quality of life and prognosis of MHD patients from dietary, sleep, treatment adherence, energy and other dimensions. This article reviews the epidemiology, etiology, diagnosis and treatment of depression in MHD patients.

6.
Angew Chem Int Ed Engl ; 62(42): e202308832, 2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37626468

RESUMO

In the molecular optimizations of non-fullerene acceptors (NFAs), extending the central core can tune the energy levels, reduce nonradiative energy loss, enhance the intramolecular (donor-acceptor and acceptor-acceptor) packing, facilitate the charge transport, and improve device performance. In this study, a new strategy was employed to synthesize acceptors featuring conjugation-extended electron-deficient cores. Among these, the acceptor CH-BBQ, embedded with benzobisthiadiazole, exhibited an optimal fibrillar network morphology, enhanced crystallinity, and improved charge generation/transport in blend films, leading to a power conversion efficiency of 18.94 % for CH-BBQ-based ternary organic solar cells (OSCs; 18.19 % for binary OSCs) owing to its delicate structure design and electronic configuration tuning. Both experimental and theoretical approaches were used to systematically investigate the influence of the central electron-deficient core on the properties of the acceptor and device performance. The electron-deficient core modulation paves a new pathway in the molecular engineering of NFAs, propelling relevant research forward.

7.
ACS Nano ; 17(17): 16993-17003, 2023 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-37606032

RESUMO

Effective photodynamic therapy (PDT) requires photosensitizers (PSs) to massively generate type I reactive oxygen species (ROS) in a less oxygen-dependent manner in the hypoxia tumor microenvironment. Herein, we present a cascade strategy to boost type I ROS, especially hydroxyl radical (OH·-), generation with an aggregation-induced emission (AIE) photosensitizer-albumin complex for hypoxia-tolerant PDT. The cationic AIE PS TPAQ-Py-PF6 (TPA = triphenylamine, Q = anthraquinone, Py = pyridine) contains three important moieties to cooperatively enhance free radical generation: the AIE-active TPA unit ensures the effective triplet exciton generation in aggregate, the anthraquinone moiety possesses the redox cycling ability to promote electron transfer, while the cationic methylpyridinium cation further increases intramolecular charge transfer and electron separation processes. Inserting the cationic TPAQ-Py-PF6 into the hydrophobic domain of bovine serum albumin nanoparticles (BSA NPs) could greatly immobilize its molecular geometry to further increase triplet exciton generation, while the electron-rich microenvironment of BSA ultimately leads to OH·- generation. Both experimental and theoretical results confirm the effectiveness of our molecular cationization and BSA immobilization cascade strategy for enhancing OH·- generation. In vitro and in vivo experiments validate the excellent antitumor PDT performance of BSA NPs, superior to the conventional polymeric encapsulation approach. Such a multidimensional cascade strategy for specially boosting OH·- generation shall hold great potential in hypoxia-tolerant PDT and related antitumor applications.


Assuntos
Radical Hidroxila , Fotoquimioterapia , Humanos , Fármacos Fotossensibilizantes/farmacologia , Espécies Reativas de Oxigênio , Soroalbumina Bovina , Antraquinonas , Hipóxia
8.
Genes Dis ; 10(3): 1090-1100, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37396539

RESUMO

Nod-like receptor family pyrin domain-containing protein 12 (NLRP12) is one of the critical pattern recognition receptors which participates in the regulation of multiple inflammatory responses. Mutations in NLRP12 cause exceptionally rare NLRP12-associated autoinflammatory disease (NLRP12-AID). So far, very few patients with NLRP12-AID have been identified worldwide; therefore, data on the clinical phenotype and genetic profile are limited. In this study, we reported 10 patients who presented mainly with periodic fever syndrome or arthritis. Next-generation sequencing (NGS) identified 6 heterozygous mutations of NLRP12, including 2 novel null mutations. Of the patients, some with same mutations showed different clinical features. Compared to healthy controls, the increased levels of cytokines were revealed in the patients' plasmas, as well as in the supernatants of patients' cells stimulated with lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α). The missense mutations did not change the protein expression; but decreased level of NLRP12 protein was shown in the null mutations. And in vitro expression assay demonstrated a truncating protein induced by the frameshift mutation. Further functional studies revealed the deleterious effect of mutations on nuclear factor-kappa B (NF-κB) signaling. Both the null and missense mutations impaired their inhibition of NF-κB activation induced by p65. Collectively, this study reported a relatively large NLRP12-AID case series. Our findings expand the clinical spectrum, and reinforce the diversity of genetic mutations and clinical phenotypes. The NLRP12-associated disorder should be considered when autoinflammatory diseases are encountered in the clinical practice, especially for patients presenting with periodic fever but no other genetic cause identified.

9.
Front Genet ; 14: 1166831, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37255714

RESUMO

As a neurodegenerative disease, Alzheimer's disease (AD) is characterized by synaptic loss, extracellular plaques of amyloid accumulation, hyperphosphorylation of tau, and neuroinflammation. Various biological processes are affected by epitranscriptomic modifications, which regulate the metabolism of mRNA in cells and regulate the expression of genes. In response to changes in m6A modification levels, the nervous system becomes dysfunctional and plays a significant role in the development of Alzheimer's disease. As a result of recent research, this paper reviews advances in the understanding of the regulatory mechanisms of m6A modification in the occurrence and development of AD. In addition, the article discusses recent research techniques related to animal models of m6A and AD. Furthermore, it discusses the possibility of studying the pathogenesis of AD at the level of the epitranscriptome, identifying early diagnostic markers, and screening for effective treatment options.

10.
Sci Total Environ ; 875: 162674, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36894074

RESUMO

The number of plastics is increasing owing to the rapid development of the plastics industry. Microplastics (MPs) are formed during the use of both petroleum-based plastics and newly developed bio-based plastics. These MPs are inevitably released into the environment and are enriched in wastewater treatment plant sludge. Anaerobic digestion is a popular sludge stabilization method for wastewater treatment plants. Understanding the potential impacts of different MPs on anaerobic digestion is critical. This paper provides a comprehensive review of the mechanisms of petroleum-based MPs and bio-based MPs in anaerobic digestion methane production and compares their potential effects on biochemical pathways, key enzyme activities, and microbial communities. Finally, it identifies problems that must be solved in the future, proposes the focus of future research, and predicts the future development direction of the plastics industry.


Assuntos
Microplásticos , Plásticos , Esgotos , Águas Residuárias , Eliminação de Resíduos Líquidos/métodos , Anaerobiose
11.
Food Nutr Res ; 672023.
Artigo em Inglês | MEDLINE | ID: mdl-36794010

RESUMO

Background: Prostate cancer is the second leading cause of cancer-related death among males in America. The patients' survival time is significantly reduced after prostate cancer develops into castration-resistant prostate cancer (CRPC). It has been reported that AKR1C3 is involved in this progression, and that its abnormal expression is directly correlated with the degree of CRPC malignancy. Genistein is one of the active components of soy isoflavones, and many studies have suggested that it has a better inhibitory effect on CRPC. Objective: This study aimed to investigate the antitumor effect of genistein on CRPC and the potential mechanism of action. Design: A xenograft tumor mouse model established with 22RV1 cells was divided into the experimental group and the control group, and the former was given 100 mg/kg.bw/day of genistein, with 22RV1, VCaP, and RWPE-1 cells cultured in a hormone-free serum environment and treated with different concentrations of genistein (0, 12.5, 25, 50, and 100 µmol/L) for 48 h. Molecular docking was used to elucidate the molecular interactions between genistein and AKR1C3. Results: Genistein inhibits CRPC cell proliferation and in vivo tumorigenesis. The western blot analysis confirmed that the genistein significantly inhibited prostate-specific antigen production in a dose-dependent manner. In further results, AKR1C3 expression was decreased in both the xenograft tumor tissues and the CRPC cell lines following genistein gavage feeding compared to the control group, with the reduction becoming more obvious as the concentration of genistein was increased. When the genistein was combined with AKR1C3 small interfering ribonucleic acid and an AKR1C3 inhibitor (ASP-9521), the inhibitory effect on the AKR1C3 was more pronounced. In addition, the molecular docking results suggested that the genistein had a strong affinity with the AKR1C3, and that it could be a promising AKR1C3 inhibitor. Conclusion: Genistein inhibits the progression of CRPC via the suppression of AKR1C3.

12.
Foodborne Pathog Dis ; 20(2): 67-79, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36779943

RESUMO

Shikonin has anticancer, anti-inflammatory, and wound healing activities. Vibrio vulnificus is an important marine foodborne pathogen with a high fatality rate and rapid pathogenesis that can infect humans through ingestion and wounds. In this study, the antibacterial activity and possible antibacterial mechanism of shikonin against V. vulnificus were investigated. In addition, the ability of shikonin to control V. vulnificus infection in both pathways was assessed by artificially contaminated oysters and full-thickness excised skin-infected mice. Shikonin treatment can cause abnormal cell membrane function, as evidenced by hyperpolarization of the cell membrane, significant decreased intracellular ATP concentration (p < 0.05), significant increased intracellular reactive oxygen species and malondialdehyde content (p < 0.05), decreased cell membrane integrity, and changes in cell morphology. Shikonin at 40 and 80 µg/mL reduced bacterial numbers in shikonin-contaminated oysters by 3.58 and 2.18 log colony-forming unit (CFU)/mL. Shikonin can promote wound healing in mice infected with V. vulnificus by promoting the formation of granulation tissue, hair follicles, and sebaceous glands, promoting epithelial cell regeneration and epidermal growth factor production. These findings suggest that shikonin has a strong inactivation effect on V. vulnificus and can be used in food production and wound healing to effectively control V. vulnificus and reduce the number of diseases associated with it.


Assuntos
Antibacterianos , Ostreidae , Vibrio vulnificus , Animais , Camundongos , Antibacterianos/farmacologia , Ostreidae/microbiologia , Vibrio vulnificus/efeitos dos fármacos , Cicatrização
13.
J Hematol Oncol ; 16(1): 2, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36650558

RESUMO

BACKGROUND: The antiphagocytic molecule CD47 is overexpressed in a wide variety of cancer cells, and antibodies targeting CD47 for cancer therapies are currently under intensive investigation. However, owing to the ubiquitous expression of CD47 on healthy cells, anti-CD47 therapies often achieve only weak therapeutic benefits and can induce severe side effects. Here, we report the generation of a pH-dependent anti-CD47 antibody (BC31M4) which selectively binds to tumors under the acidic solid tumor microenvironment. METHODS: BC31M4 was generated using antibody phage display and a pH-dependent selection strategy. The pH-dependent binding and blocking activities of BC31M4 were verified using in vitro assays, and the structural basis of the pH-dependent binding property was characterized. BC31M4's antitumor effect was confirmed by both phagocytosis assays and studies in xenograft models. The tumor selectivity, mechanism of action, PK properties, side effects, and therapeutic efficacy were further evaluated in humanized (hCD47 and its receptor hSIRPα) immunocompetent syngeneic mouse models. RESULTS: The crystal structure reveals that two histidines locate within the CDRs of the light chain directly contribute to the pH-dependent binding of BC31M4. BC31M4 promotes macrophage phagocytosis of tumor cells more potently at acidic-pH than at physiological-pH. Our hCD47/hSIRPα humanized syngeneic mouse model results demonstrated that BC31M4 selectively accumulates in tumors but not in normal tissues. BC31M4 causes minimal side effects and exhibits superior PK properties as compared to the other examined anti-CD47 antibodies. When combined with adoptive T cell transfer, BC31M4 efficiently promotes adaptive immune responses against tumors and also induces immune memory. Moreover, we show that BC31M4's antitumor effects rely on an Fc that mediates strong effector functions. CONCLUSIONS: Our study illustrates that the development of a tumor-selective, pH-dependent anti-CD47 antibody safely confers strong therapeutic effects against solid tumors, thus providing a promising therapeutic strategy to overcome the challenges of anti-CD47 therapy.


Assuntos
Antígeno CD47 , Neoplasias , Animais , Humanos , Camundongos , Anticorpos/uso terapêutico , Modelos Animais de Doenças , Concentração de Íons de Hidrogênio , Macrófagos/metabolismo , Neoplasias/patologia , Fagocitose , Microambiente Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Nat Biomed Eng ; 7(1): 8-23, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36424464

RESUMO

The cell-surface glycoprotein CD98-a subunit of the LAT1/CD98 amino acid transporter-is an attractive target for cancer immunotherapies, but its widespread expression has hampered the development of CD98-targeting antibody therapeutics. Here we report that an anti-CD98 antibody, identified via the screening of phage-display libraries of CD98 single-chain variable fragments with mutated complementarity-determining regions, preserves the physiological function of CD98 and elicits broad-spectrum crystallizable-fragment (Fc)-mediated anti-tumour activity (requiring Fcγ receptors for immunoglobulins, macrophages, dendritic cells and CD8+ T cells, as well as other components of the innate and adaptive immune systems) in multiple xenograft and syngeneic tumour models established in CD98-humanized mice. We also show that a variant of the anti-CD98 antibody with pH-dependent binding, generated by solving the structure of the antibody-CD98 complex, displayed enhanced tumour-specific activity and pharmacokinetics. pH-dependent antibody variants targeting widely expressed antigens may lead to superior therapeutic outcomes.


Assuntos
Neoplasias , Anticorpos de Cadeia Única , Animais , Humanos , Camundongos , Linfócitos T CD8-Positivos , Concentração de Íons de Hidrogênio , Proteína-1 Reguladora de Fusão/imunologia
15.
Foods ; 13(1)2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38201059

RESUMO

Intensive aquaculture combatting the decline of large yellow croaker populations can trigger bacterial outbreaks, resulting in extensive antibiotic use. In this study, we screened 5 aquaculture sites in the coastal areas of Zhejiang and identified 17 antibiotics in large yellow croakers using UPLC-MS/MS. The distribution and occurrence of antibiotic pollutants were different in the different tissues of large yellow croakers, being primarily dominated by quinolones. Relatively higher average residue levels of enrofloxacin and ciprofloxacin were detected in the inedible parts, specifically the gills (37.29 µg/kg). Meanwhile, relatively high average residue levels of enrofloxacin and ciprofloxacin were also found in the edible parts, particularly in the muscle (23.18 µg/kg). We observed that the residue levels detected in the swim bladder exceeded the prescribed limit for fish muscle, but there is currently no specific regulatory limit established for this particular tissue. Despite the HI values of enrofloxacin and ciprofloxacin being below 0.01, the health risks should not be disregarded. The findings of this research provide significant practical implications for assessing antibiotic contamination and enhancing the risk management of coastal regions.

16.
Mol Ther Oncolytics ; 27: 256-269, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36458200

RESUMO

The clinical use of anti-EGFR antibody-based cancer therapy has been limited by antibody-EGFR binding in normal tissues, so developing pH-dependent anti-EGFR antibodies that selectively bind with EGFR in tumors-by taking advantage of the acidity of tumor microenvironment relative to normal tissues-may overcome these limitations. Here, we generated pH-dependent anti-EGFR antibodies with cross-species reactivity for human and mouse EGFR, and we demonstrate that pH-dependent antibodies exhibit tumor-selective binding by binding strongly to EGFR under acidic conditions (pH 6.5) but binding weakly under neutral (pH 7.4) conditions. Based on screening a non-immune human antibody library and antibody affinity maturation, we initially generated antibodies with cross-species reactivity for human and mouse EGFR. A structure model was subsequently constructed and interrogated for hotspots affecting pH-dependent binding, which supported development of a cross-reactive pH-dependent anti-EGFR antibody, G532. Compared with its non-pH-dependent antibody variant, G532 exhibits improved tumor selectivity, tumor penetration, and antitumor activity. Thus, beyond showing that pH-dependent anti-EGFR antibodies can overcome multiple limitations with antibody-based cancer therapies targeting EGFR, our study illustrates a structure-guided antibody-antigen binding pH-dependency engineering strategy to enhance antibody tumor selectivity and tumor penetration, which can inform the future development of antibody-based cancer therapies targeting other ubiquitously expressed molecules.

17.
Foods ; 11(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36496708

RESUMO

Litsea cubeba essential oil (LC-EO) has anti-insecticidal, antioxidant, and anticancer proper-ties; however, its antimicrobial activity toward Cronobacter sakazakii has not yet been researched extensively. The objective of this study was to investigate the antimicrobial and antibiofilm effects of LC-EO toward C. sakazakii, along with the underlying mechanisms. The minimum inhibitory concentrations of LC-EO toward eight different C. sakazakii strains ranged from 1.5 to 4.0 µL/mL, and LC-EO exposure showed a longer lag phase and lower specific growth compared to untreated bacteria. LC-EO increased reactive oxygen species production, decreased the integrity of the cell membrane, caused cell membrane depolarization, and decreased the ATP concentration in the cell, showing that LC-EO caused cellular damage associated with membrane permeability. LC-EO induced morphological changes in the cells. LC-EO inhibited C. sakazakii in reconstituted infant milk formula at 50 °C, and showed effective inactivation of C. sakazakii biofilms on stainless steel surfaces. Confocal laser scanning and attenuated total reflection-Fourier-transform infrared spectrometry indicated that the biofilms were disrupted by LC-EO. These findings suggest a potential for applying LC-EO in the prevention and control of C. sakazakii in the dairy industry as a natural antimicrobial and antibiofilm agent.

18.
Nat Commun ; 13(1): 5559, 2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36138041

RESUMO

Coherent interaction between matter and light field induces both optical Stark effect and Bloch-Siegert shift. Observing the latter has been historically challenging, because it is weak and is often accompanied by a much stronger Stark shift. Herein, by controlling the light helicity, we can largely restrict these two effects to different spin-transitions in CsPbI3 perovskite quantum dots, achieving room-temperature Bloch-Siegert shift as strong as 4 meV with near-infrared pulses. The ratio between the Bloch-Siegert and optical Stark shifts is however systematically higher than the prediction by the non-interacting, quasi-particle model. With a model that explicitly accounts for excitonic effects, we quantitatively reproduce the experimental observations. This model depicts a unified physical picture of the optical Stark effect, biexcitonic optical Stark effect and Bloch-Siegert shift in low-dimensional materials displaying strong many-body interactions, forming the basis for the implementation of these effects to information processing, optical modulation and Floquet engineering.

19.
Nat Mater ; 21(11): 1282-1289, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36075966

RESUMO

Anisotropic exchange splitting in semiconductor quantum dots results in bright-exciton fine-structure splitting important for quantum information processing. Direct measurement of fine-structure splitting usually requires single/few quantum dots at liquid-helium temperature because of its sensitivity to quantum dot size and shape, whereas measuring and controlling fine-structure splitting at an ensemble level seem to be impossible unless all the dots are made to be nearly identical. Here we report strong bright-exciton fine-structure splitting up to 1.6 meV in solution-processed CsPbI3 perovskite quantum dots, manifested as quantum beats in ensemble-level transient absorption at liquid-nitrogen to room temperature. The splitting is robust to quantum dot size and shape heterogeneity, and increases with decreasing temperature, pointing towards a mechanism associated with orthorhombic distortion of the perovskite lattice. Effective-mass-approximation calculations reveal an intrinsic 'fine-structure gap' that agrees well with the observed fine-structure splitting. This gap stems from an avoided crossing of bright excitons confined in orthorhombically distorted quantum dots that are bounded by the pseudocubic {100} family of planes.

20.
Toxicol In Vitro ; 84: 105455, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35985572

RESUMO

Acrylamide (ACR), a neurotoxic substance, is characterized by a range of industrial and population exposures. The effects of ACR on synapses have been examined, but the regulation and molecular mechanism of key proteins related to ACR and its metabolite glycidamide (GA) have not been elucidated. In this study, we constructed two co-culture systems to mimic neurons that do not express and overexpress CYP2E1. In these co-cultures, we observed the effects and relative influence of ACR and GA on cell survival as well as synaptic structural and functional plasticity. Next, we investigated the relationship between ACR-induced nerve damage and key proteins in the postsynaptic membrane. After ACR exposure, cell death and synaptic damage were significantly worse in CYP2E1-overexpressing co-culture systems, suggesting that ACR-induced neurotoxicity may be related to metabolic efficiency (including CYP2E1 activity). Moreover, with increasing doses of ACR, the key postsynaptic membrane proteins PSD-95 expression was reduced and CaMKII and NMDAR-2B phosphorylation was increased. ACR exposure also triggered a rapid dose- and time-dependent increase in intracellular Ca2+, whose changes can affect the expression of the above-mentioned key proteins. In summary, we clarified the relationship between ACR exposure, neuronal damage and postsynaptic plasticity and proposed an ACR-CYP2E1-GA: Ca2+-PSD-95-NMDAR-Ca2+-CaMKII effect chain. This information will further improve the development of an alternative pathway strategy for investigating the risk posed by ACR.


Assuntos
Neuroblastoma , Síndromes Neurotóxicas , Acrilamida/toxicidade , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Técnicas de Cocultura , Citocromo P-450 CYP2E1/metabolismo , Humanos , Receptores de N-Metil-D-Aspartato
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