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1.
Anal Chem ; 96(11): 4665-4672, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38456411

RESUMO

Detecting scandium (Sc) with high selectivity and sensitivity is a challenging task due to its chemical similarity to other rare earth ions. Our findings show that the fluorescence of the complex fluorescent indicator calcein (CL) is quenched under acidic conditions (pH = 2), and Sc3+ strongly inhibits this process. The results demonstrate that CL forms multimers and precipitates out of the solution under acidic conditions, while Sc3+ causes a significant decrease in the scattering intensity of the solution. Additional experiments revealed that the strong Lewis acid nature of Sc3+ complexes with the carboxyl groups of CL leads to increased dispersion of CL even under acidic conditions, thus enhancing its absorption and fluorescence. The complexation ratio of Sc3+ and CL was investigated through spectral titrations and theoretical calculations. The interaction between Sc3+ and CL is the strongest among rare earth and common metal ions due to the smallest ionic radius, resulting in high selectivity. The fluorescence turn-on strategy had a linear range of 0.04 to 2.25 µM under optimal conditions, with a detection limit of 20 nM for Sc3+. The combination of 3D printing and a smartphone program allows for portable on-site analysis of Sc3+. Mineral and water samples were used to demonstrate the potential of this strategy for the rapid, selective, and sensitive analysis of low levels of Sc3+.

2.
Anal Chem ; 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38966896

RESUMO

The urgent need for field detection of uranium in seawater is 2-fold: to provide prompt guidance for uranium extraction and to prevent human exposure to nuclear radiation. However, current methods for this purpose are largely hindered by bulky instrumentation, high costs of developed materials, and severe matrix interferences, which limit their further application in the field. Herein, we demonstrated a portable and label-free strategy for the field detection of uranyl in seawater based on the efficient photocleavage of DNA. Further experiments confirmed the generation of ultraviolet (UV) light-induced reactive oxygen species (ROS), such as O2•- and •OH, which fragmented oligomeric DNA in the presence of uranyl and UV light. Detailed studies showed that DNA significantly enhances uranyl absorption in the UV-visible region, leading to the generation of more ROS. A fluorescence system for the selective detection of uranyl in seawater was established by immobilizing two complementary oligonucleotides with the fluorescent dye SYBR Green I. The strategy of UV-induced photocleavage offers high selectivity, excellent interference immunity, and high sensitivity for uranyl, with a detection limit of 6.8 nM. Additionally, the fluorescence can be visually detected using a 3D-printed miniaturized device integrated with a smartphone. This method has been successfully applied to the on-site detection of uranyl in seawater in 18 Chinese coastal cities and along the coast of Hainan Island within 3 min for a single sample. The sample testing and field analysis results indicate that this strategy has promising potential for real-time monitoring of trace uranyl in China's coastal waters. It is expected to be utilized for the rapid assessment of nuclear contamination and nuclear engineering construction.

3.
Small ; 20(12): e2302410, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37635113

RESUMO

Herein, a hybrid substrate for surface-enhanced Raman scattering (SERS) is fabricated, which couples localized surface plasmon resonance (LSPR), charge transfer (CT) resonance, and molecular resonance. Exfoliated 2D TiS2 nanosheets with semimetallic properties accelerate the CT with the tested analytes, inducing a remarkable chemical mechanism enhancement. In addition, the LSPR effect is coupled with a concave gold array located underneath the thin TiS2 nanosheet, providing a strong electromagnetic enhancement. The concave gold array is prepared by etching silicone nanospheres assembled on larger polystyrene nanospheres, followed by depositing a gold layer. The LSPR intensity near the gold layer can be adjusted by changing the layer thickness to couple the molecular and CT resonances, in order to maximize the SERS enhancement. The best SERS performance is recorded on TiS2-nanosheet-coated plasmonic substrates, with a detectable methylene blue concentration down to 10-13 m and an enhancement factor of 2.1 × 109 and this concentration is several orders of magnitude lower than that of the TiS2 nanosheet (10-11 m) and plasmonic substrates (10-9 m). The present hybrid substrate with triple-coupled resonance further shows significant advantages in the label-free monitoring of curcumin (a widely applied drug for treating multiple cancers and inflammations) in serum and urine.

4.
J Exp Child Psychol ; 246: 105966, 2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38852402

RESUMO

Preschoolers are notoriously poor at delaying gratification and saving limited resources, yet evidence-based methods of improving these behaviors are lacking. Using the marble game saving paradigm, we examined whether young children's saving behavior would increase as a result of engaging in future-oriented imagination using a storyboard. Participants were 115 typically developing 4-year-olds from a midwestern U.S. metropolitan area (Mage = 53.48 months, SD = 4.14, range = 47-60; 54.8% female; 84.5% White; 7.3% Hispanic/Latino ethnicity; median annual household income = $150,000-$174,999). Children were randomly assigned to one of four storyboard conditions prior to the marble game: Positive Future Simulation, Negative Future Simulation, Positive Routine, or Negative Routine. In each condition, children were asked to imagine how they would feel in the future situation using a smiley face rating scale. Results showed that children were significantly more likely to save (and to save more marbles) in the experimental conditions compared with the control conditions (medium effect sizes). Moreover, imagining saving for the future (and how good that would feel) was more effective at increasing saving behaviors than imagining not saving (and how bad that would feel). Emotion ratings were consistent with the assigned condition, but positive emotion alone did not account for these effects. Results held after accounting for game order and verbal IQ. Implications of temporal psychological distancing and emotion anticipation for children's future-oriented decision making are discussed.

5.
Sensors (Basel) ; 24(7)2024 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-38610564

RESUMO

In order to achieve efficient recognition of 3D images and reduce the complexity of network parameters, we proposed a novel 3D image recognition method combining deep neural networks with fractional-order Chebyshev moments. Firstly, the fractional-order Chebyshev moment (FrCM) unit, consisting of Chebyshev moments and the three-term recurrence relation method, is calculated separately using successive integrals. Next, moment invariants based on fractional order and Chebyshev moments are utilized to achieve invariants for image scaling, rotation, and translation. This design aims to enhance computational efficiency. Finally, the fused network embedding the FrCM unit (FrCMs-DNNs) extracts depth features to analyze the effectiveness from the aspects of parameter quantity, computing resources, and identification capability. Meanwhile, the Princeton Shape Benchmark dataset and medical images dataset are used for experimental validation. Compared with other deep neural networks, FrCMs-DNNs has the highest accuracy in image recognition and classification. We used two evaluation indices, mean square error (MSE) and peak signal-to-noise ratio (PSNR), to measure the reconstruction quality of FrCMs after 3D image reconstruction. The accuracy of the FrCMs-DNNs model in 3D object recognition was assessed through an ablation experiment, considering the four evaluation indices of accuracy, precision, recall rate, and F1-score.

6.
Molecules ; 29(7)2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38611753

RESUMO

The fruits of Cornus officinalis are used not only as a popular health food to tonify the liver and kidney, but also as staple materials to treat dementia and other age-related diseases. The pharmacological function of C. officinalis fruits with or without seeds is controversial for treating some symptoms in a few herbal prescriptions. However, the related metabolite and pharmacological information between its pericarps and seeds are largely deficient. Here, comparative metabolomics analysis between C. officinalis pericarps and seeds were conducted using an ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, and therapeutic effects were also evaluated using several in vitro bioactivity arrays (antioxidant activity, α-glucosidase and cholinesterase inhibitory activities, and cell inhibitory properties). A total of 499 secondary metabolites were identified. Thereinto, 77 metabolites were determined as key differential metabolites between C. officinalis pericarps and seeds, and the flavonoid biosynthesis pathway was identified as the most significantly different pathway. Further, 47 metabolites were determined as potential bioactive constituents. In summary, C. officinalis seeds, which demonstrated higher contents in total phenolics, stronger in vitro antioxidant activities, better α-glucosidase and butyrylcholinesterase inhibitory activities, and stronger anticancer activities, exhibited considerable potential for food and health fields. This work provided insight into the metabolites and bioactivities of C. officinalis pericarps and seeds, contributing to their precise development and utilization.


Assuntos
Cornus , Frutas , Butirilcolinesterase , alfa-Glucosidases , Sementes , Compostos Fitoquímicos/farmacologia
7.
Anal Chem ; 95(37): 13949-13956, 2023 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-37659071

RESUMO

Iodine is an essential element that is used to make thyroid hormones. However, people usually ignore their iodine nutrition level, thus leading to a series of thyroid diseases, particularly in areas where medical resources are scarce. Thus, development of a portable, economical, and simple method for the detection of urinary iodine is of significant importance. Herein, a solid-phase fluorescence filter effect (SPFFE) induced by iodine was used to develop an SPFFE-based point-of-care testing (POCT) platform for the detection of urinary iodine by coupling with headspace sample introduction. This method can not only alleviate the matrix interference that occurred in the conventional inner filter effect (IFE) but also achieve high sensitivity. Furthermore, the urinary iodine (UI) POCT platform was developed through the integration of a sample pretreatment and fluorescence readout. This whole system costs less than US $20 and provides accurate temperature control and a portable fluorescence reading within 15-20 min. Compared to the traditional IFE-based assay, the SPFFE-based POCT platform allows the selective detection of iodine as low as 10 nM and has a linear range of 0.05-4 µM. In addition, it provides notable visualization from blue-violet to orange-red in the presence of iodine, which tends to indicate the iodine nutritional status of the human body. Eventually, the clinical applicability and feasibility of the UIPOCT platform as an early diagnostic test kit were confirmed by determining the iodine in urine samples from children and pregnant women.


Assuntos
Iodo , Sistemas Automatizados de Assistência Junto ao Leito , Gravidez , Humanos , Criança , Feminino , Gestantes , Testes Imediatos , Bioensaio
8.
Anal Chem ; 95(49): 18303-18308, 2023 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-38019658

RESUMO

Salivary pepsin has been proposed as a promising diagnostic marker for gastroesophageal reflux disease (GERD). However, the activity of human pepsin is strongly influenced by pH, and the acidic condition (pH ∼ 2) is optimal, which is a contradiction for the pepsin detection kit based on its catalytic activity. Thus, its accurate quantification in saliva (neutral pH) by readily rapid tools with simplicity and low cost is still challenging. Herein, a convenient fluorescence assay has been developed for the rapid detection of pepsin at neutral pH based on its electrostatic interaction with SYBR Green (SG) rather than the bioactivity. At neutral pH, the positively charged SG fluorophore can be effectively adsorbed by the negatively charged pepsin due to the low isoelectric point (pI) and large molecular size of pepsin. Thus, the molecular rotation of SG is limited, and its fluorescence intensity is significantly increased. The strategy was further confirmed to have the same fluorescence response as that of normally active and inactivated pepsin. Due to the unique pI of pepsin, the fluorescence strategy is highly selective for pepsin compared to other proteins. On the basis of this strategy, a smartphone-based fluorescence capture device integrated with a programmed Python program was fabricated for both color recognition and the accurate detection of pepsin within 3 min. Under the optimal conditions, this turn-on sensor allowed for the on-site analysis of pepsin with a detection limit of 0.2 µg/mL. Moreover, this strategy was successfully used to assess salivary pepsin to aid in the noninvasive diagnosis of GERD.


Assuntos
Refluxo Gastroesofágico , Saliva , Humanos , Saliva/química , Pepsina A/metabolismo , Eletricidade Estática , Refluxo Gastroesofágico/diagnóstico , Refluxo Gastroesofágico/metabolismo , Concentração de Íons de Hidrogênio
9.
Anal Chem ; 95(18): 7363-7371, 2023 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-37127404

RESUMO

Excessive consumption of Δ9-tetrahydrocannabinol (THC) severely endangers human health and has raised public safety concerns. However, its quantification by readily rapid tools with simplicity and low cost is still challenging. Herein, we found that a G-rich THC aptamer (THC1.2) can tightly bind to thioflavin T (ThT) with strong fluorescence, which would be specifically quenched in the presence of THC. Based on that, a label-free ratiometric fluorescent sensor for the sensing of THC and its metabolite (THC-COOH) based on THC1.2/ThT as a color emitter and red CdTe quantum dots as reference fluorescence was constructed. Notably, a transition of the fluorescent color of the ratiometric probe from green to red can be instantly observed upon the increased concentration of THC and THC-COOH. Furthermore, a portable smartphone-based fluorescence device integrated with a self-programmed Python program was fabricated and used to accomplish on-site monitoring of THC and THC-COOH within 5 min. Under optimized conditions, this ratiometric fluorescent sensor allowed for an instant response toward THC and its metabolite with considerable limits of detection of 97 and 254 nM, respectively. The established sensor has been successfully applied to urine and saliva samples and exhibited satisfactory recoveries (88-116%). This ratiometric fluorescent sensor can be used for the simultaneous detection of THC and THC-COOH with the advantages of rapidness, low cost, ease of operation, and portability, providing a promising strategy for on-site detection and facilitating law enforcement regulation and roadside control of THC.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Humanos , Dronabinol/análise , Cromatografia Gasosa-Espectrometria de Massas , Smartphone , Telúrio , Corantes , Corantes Fluorescentes , Limite de Detecção
10.
Microb Pathog ; 184: 106367, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37778704

RESUMO

Macrophages play a pivotal role in controlling Mycobacterium infection, and the pathogen thrives in the event of immune evasion and immunosuppression of macrophages. Mammalian cell entry proteins (Mce) are required for Mycobacterium tuberculosis (M. tb) growth and the host cell's initial phagocytosis and cytokine response. Mce2D protein is one of a family of proteins that infect M. tb; however, the function and mechanism of action remain unclear. In this study, we constructed the Mce2D knockout strain using Mycobacterium smegmatis to study the function of Mce2D in the infection of macrophages. The results indicated that compared to the knockout strain, the release of proinflammatory cytokines (TNF-α and IL-1ß) reduced when WT strain infected the macrophages. Moreover, Mce2D boosted the metabolism of oxidized fatty acids, increased the energy supply of TCA, and lowered the glycolysis of glucose in macrophages after bacterial infection, all of which prevented the polarization of macrophages to M1, which was driven by the fact that Mce2D blocked ERK2 phosphorylation by interacting with ERK2 through its DEF motif. This, in turn, promoted nuclear translocation of HIF-1α, allowing signal accumulation, which increased the HIF-1α transcription levels. Finally, the mouse infection experiment showed that Mce2D caused blockage of M1 polarization of alveolar macrophages, resulting in reduced bactericidal activity and antigen presentation, weakening Th1 cell-mediated immune response and helping bacteria escape the immune system. Our results reveal that Mce2D causes immune escape by blocking M1 polarization in macrophages, providing potential targets for the rational design of therapies against M. tb infection.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Camundongos , Animais , Mycobacterium tuberculosis/metabolismo , Macrófagos/microbiologia , Transdução de Sinais , Sistema de Sinalização das MAP Quinases , Citocinas/metabolismo , Mamíferos/metabolismo
11.
Phys Rev Lett ; 130(4): 043201, 2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36763419

RESUMO

The Floquet engineering opens the way to create new topological states without counterparts in static systems. Here, we report the experimental realization and characterization of new anomalous topological states with high-precision Floquet engineering for ultracold atoms trapped in a shaking optical Raman lattice. The Floquet band topology is manipulated by tuning the driving-induced band crossings referred to as band inversion surfaces (BISs), whose configurations fully characterize the topology of the underlying states. We uncover various exotic anomalous topological states by measuring the configurations of BISs that correspond to the bulk Floquet topology. In particular, we identify an unprecedented anomalous Floquet valley-Hall state that possesses anomalous helical-like edge modes protected by valleys and a chiral state with high Chern number.

12.
Nanotechnology ; 34(24)2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36898149

RESUMO

A particular bird's nest-like pseudo-boehmite (PB) composed of cohesive nanostrips was prepared by a novel and facile approach based on the reaction of Al-Ga-In-Sn alloy and water, together with ammonium carbonate. The PB possesses a large specific surface area (465.2 m2g-1), pore volume (1.0 cm3g-1), and pore diameter (8.7 nm). Subsequently, it was utilized as a precursor to form the TiO2/γ-Al2O3nanocomposite for tetracycline hydrochloride removal. The removal efficiency can reach above 90% at TiO2:PB = 1:1.5 under the Sunlight irradiation simulated by a LED lamp. Our results indicate that the nest-like PB is a promising carrier precursor for efficient nanocomposite catalysts.

13.
Anal Bioanal Chem ; 415(18): 3817-3830, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36633622

RESUMO

Nanozymes exhibit their great potential as alternatives to natural enzymes. In addition to catalytic activity, nanozymes also need to have biologically relevant catalytic reactions at physiological pH to fit in the definition of an enzyme and to achieve efficient analytical applications. Previous reviews in the nanozyme field mainly focused on the catalytic mechanisms, activity regulation, and types of catalytic reactions. In this paper, we discuss efforts made on the substrate-dependent catalytic activity of nanozymes at neutral pH. First, the discrepant catalytic activities for different substrates are compared, where the key differences are the characteristics of substrates and the adsorption of substrates by nanozymes at different pH. We then reviewed efforts to enhance reaction activity for model chromogenic substrates and strategies to engineer nanomaterials to accelerate reaction rates for other substrates at physiological pH. Finally, we also discussed methods to achieve efficient sensing applications at neutral pH using nanozymes. We believe that the nanozyme is catching up with enzymes rapidly in terms of reaction rates and reaction conditions. Designing nanozymes with specific catalysis for efficient sensing remains a challenge.


Assuntos
Nanoestruturas , Catálise , Concentração de Íons de Hidrogênio , Compostos Cromogênicos
14.
J Exp Child Psychol ; 234: 105708, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37257371

RESUMO

Children's inclination to prioritize others' welfare over their own (hyperaltruism) was investigated from a developmental and cross-cultural perspective. The distribution of rewarding or aversive items to self and another child was probed in 3- to 14-year-old children (final sample: N = 158; 87 girls) from urban China (n = 51; Mage = 9.1 years, SD = 1.81; 27 girls), urban United States (n = 55; Mage = 8.89 years, SD = 2.18; 30 girls), and rural Samoa (n = 52; Mage = 8.6 years, SD = 2.61; 30 girls). In two counterbalanced conditions, the children were first asked to split either rewards (stickers or treats) or potentially harmful insects (biting bugs) with another child. In a third condition, children were asked to choose various levels of hypothetical pain to be inflicted on either themselves or another child in exchange for commensurate rewards. Results indicated that in conditions where children distributed rewards, older children were more egalitarian (i.e., gave an equal number of candies to self and other) compared with younger children. However, in conditions where they needed to allocate potential harm, older children displayed more altruism (taking more harm onto themselves so that others could be spared). These results varied by culture, where Chinese children showed more altruism, U.S. children were more egalitarian, and Samoan children showed no clear patterns of either egalitarianism or altruism. The results show that although there are some universal trends toward egalitarian and altruistic ways of sharing, significant group differences exist.


Assuntos
Afeto , Altruísmo , Feminino , Humanos , Criança , Estados Unidos , Adolescente , Pré-Escolar , Recompensa , China
15.
Molecules ; 28(8)2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-37110537

RESUMO

To study the importance of the adsorption mechanism of methane (CH4) and carbon dioxide (CO2) in coal for coalbed methane development, we aimed to reveal the influence mechanism of adsorption pressure, temperature, gas properties, water content, and other factors on gas molecular adsorption behavior from the molecular level. In this study, we selected the nonsticky coal in Chicheng Coal Mine as the research object. Based on the coal macromolecular model, we used the molecular dynamics (MD) and Monte Carlo (GCMC) methods to simulate and analyze the conditions of different pressure, temperature, and water content. The change rule and microscopic mechanism of the adsorption amount, equal adsorption heat, and interaction energy of CO2 and CH4 gas molecules in the coal macromolecular structure model establish a theoretical foundation for revealing the adsorption characteristics of coalbed methane in coal and provide technical support for further improving coalbed methane extraction.

16.
Molecules ; 28(19)2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37836775

RESUMO

In order to study the importance of the diffusion mechanism of CH4 and CO2 in coal for the development of coalbed methane, the aim of this paper is to reveal the influence mechanism of pressure, temperature, water content and other factors on the molecular diffusion behavior of gas at the molecular level. In this paper, non-sticky coal in Chicheng Coal Mine is taken as the research object. Based on the molecular dynamics method (MD) and Monte Carlo (GCMC) method, the diffusion characteristics and microscopic mechanism of CH4 and CO2 in coal under different pressures (100 kPa-10 MPa), temperatures (293.15-313.15 K) and water contents (1-5%) were analyzed in order to lay a theoretical foundation for revealing the diffusion characteristics of CBM in coal, and provide technical support for further improving CBM extraction. The results show that high temperature is conducive to gas diffusion, while high pressure and water are not conducive to gas diffusion in the coal macromolecular model.

17.
Yi Chuan ; 45(11): 1039-1051, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-38764269

RESUMO

Circular RNA (circRNA) is a category of non-coding RNAs characterized by the absence of a 5'-cap and 3'-poly(A) tail, and participates in the physiological processes of various human diseases. Nonetheless, the diagnostic and functional significance of circRNAs in active pulmonary tuberculosis (ATB) remains uncertain. Consequently, the purpose of this study is to investigate whether hsa_circ_0007460 can be employed as a potential diagnostic biomarker in ATB patients and explore its function. The result of real-time quantitative fluorescent PCR (RT-qPCR) validated a notable increase in the expression of hsa_circ_0007460 in the peripheral blood of 32 ATB patients, as well as in THP-1 human macrophages infected with Bacillus Calmette Guerin (BCG) which is an attenuated strain of Mycobacterium bovis. Additionally, the receiver operating curve (ROC) illustrated that the area under the ROC curve (AUC), sensitivity and specificity were 0.7474, 76.67%, and 78.13% respectively. RNase R, Actinomycin D and other experiments confirmed that hsa_circ_0007460 was stabler than its linear mRNA, indicating that hsa_circ_0007460 has potential as a diagnostic biomarker of ATB. Furthermore, Western blot (WB), Cell Counting Kit-8 (CCK-8), plate counting, and immunofluorescence experiments revealed that hsa_circ_0007460 could regulate apoptosis and autophagy of macrophages. The downstream miRNAs and mRNAs were subsequently predicted using bioinformatics, and the hsa circ 0007460/hsa-miR-3127-5p/PATZ1 axis was built. These above results suggest that hsa_circ_0007460 is substantially up-regulated in the peripheral blood of patients with ATB and can be utilized as a potential diagnostic biomarker. In addition, hsa_circ_0007460 can promote apoptosis of macrophages and inhibit autophagy of macrophages, thereby promoting the survival of BCG.


Assuntos
Apoptose , Autofagia , Macrófagos , Mycobacterium tuberculosis , RNA Circular , Humanos , Autofagia/genética , RNA Circular/genética , Macrófagos/microbiologia , Macrófagos/metabolismo , Apoptose/genética , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/fisiologia , Feminino , Adulto , Masculino , Tuberculose Pulmonar/genética , Tuberculose Pulmonar/microbiologia , Células THP-1 , Pessoa de Meia-Idade
18.
Phys Rev Lett ; 126(6): 060402, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33635703

RESUMO

We study the decay mechanism of the gapped lowest-lying axial excitation of a quasipure atomic Bose-Einstein condensate confined in a cylindrical box trap. Owing to the absence of accessible lower-energy modes, or direct coupling to an external bath, this excitation is protected against one-body (linear) decay, and the damping mechanism is exclusively nonlinear. We develop a universal theoretical model that explains this fundamentally nonlinear damping as a process whereby two quanta of the gapped lowest excitation mode couple to a higher-energy mode, which subsequently decays into a continuum. We find quantitative agreement between our experiments and the predictions of this model. Finally, by strongly driving the system below its (lowest) resonant frequency, we observe third-harmonic generation, a hallmark of nonlinear behavior.

19.
Nanotechnology ; 33(9)2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34808606

RESUMO

Mesoporous adsorbents and polymer deodorants are difficult to implement on a large scale because of their complicated preparation methods. Herein, a mesoporous adsorbent (CGSA) with a specific surface area of 564 m2g-1and a pore volume of 0.807 cm3g-1was prepared from solid waste coal gasification slag using a simple acid leaching process. The adsorption thermodynamics and adsorption kinetics results verified that the adsorption mechanism of propane on CGSA was mainly physisorption. Then the universality of CGSA in different polymers was investigated by introducing CGSA and its commercialized counterparts (CaCO3, and zeolite) into four common polymers. When the filler content was 30 wt%, the average reinforcement effect of CGSA on the tensile, flexural, and impact strengths of the four polymers was 46.68%, 83.62%, and 211.90% higher than that of CaCO3, respectively. Gas chromatography results also showed that CGSA significantly decreased total volatile organic compound emissions from the composites, and its optimal deodorization performance reached 69.58%, 81.33%, and 91.09% for different polymers, respectively, far exceeding that of zeolite. Therefore, this study showed that low-cost, high-performance, and multifunctional mesoporous polymer fillers with excellent universality can be manufactured from solid contaminants.

20.
Phys Rev Lett ; 125(26): 260603, 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33449755

RESUMO

The famous Kibble-Zurek mechanism offers us a significant clue to study quantum phase transitions out of equilibrium. Here, we investigate an intriguing phenomenon of a spin-orbit coupled Bose-Einstein condensate by quenching the Raman coupling strength from a high-symmetry phase (nonmagnetic phase) to a low-symmetry phase (magnetic phase). When crossing the critical point, the fluctuation of momentum distribution leads to delayed bifurcation structures. Simultaneously, the domain information emerges in momentum space. Moreover, the universal scalings of spatiotemporal dynamics are extracted from the fluctuations and domains, which manifests homogeneous and inhomogeneous Kibble-Zurek power laws at different timescales. Our work demonstrates a paradigmatic study on the inhomogeneous Kibble-Zurek mechanism.

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