Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Adv Healthc Mater ; : e2304648, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38597827

RESUMEN

Drug-resistant and metastatic cancer cells such as a small population of cancer stem cells (CSCs) play a crucial role in metastasis and relapse. Conventional small-molecule chemotherapeutics, however, are unable to eradicate drug-resistant CSCs owing to limited interface inhibitory effects. Herein, it is reported that enhanced interfacial inhibition leading to eradication of drug-resistant CSCs can be dramatically induced by self-insertion of bioactive graphene quantum dots (GQDs) into DNA major groove (MAG) sites in cancer cells. Since transcription factors regulate gene expression at the MAG site, MAG-targeted GQDs exert greatly enhanced interfacial inhibition, downregulating the expression of a collection of cancer stem genes such as ALDH1, Notch1, and Bmi1. Moreover, the nanoscale interface inhibition mechanism reverses cancer multidrug resistance (MDR) by inhibiting MDR1 gene expression when GQDs are used at a nontoxic concentration (1/4 × half-maximal inhibitory concentration (IC50)) as the MDR reverser. Given their high efficacy in interfacial inhibition, CSC-mediated migration, invasion, and metastasis of cancer cells can be substantially blocked by MAG-targeted GQDs, which can also be harnessed to sensitize clinical cytotoxic agents for improved efficacy in combination chemotherapy. These findings elucidate the inhibitory effects of the enhanced nano-bio interface at the MAG site on eradicating CSCs, thus preventing cancer metastasis and recurrence.

2.
ACS Omega ; 9(13): 15439-15448, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38585087

RESUMEN

Aiming at the problem of restart-up for a heavy oil-water ring transportation pipeline due to instability and damage of the water ring, based on the self-developed design of a small indoor loop simulation experimental device and taking four kinds of ordinary heavy oil in the Lvda oilfield as the research object, the change trend of restart-up pressure drop with time is experimentally studied when the pipeline is restarted-up after shutdown at a constant water flow. On the basis of the regression analysis of the orthogonal restart-up experimental data of four factors (oil holdup, oil viscosity, standstill period, and water cleaning superficial velocity) and mixed levels by the statistical product and service solutions statistical analysis software, a multivariate nonlinear restart-up maximum pressure drop prediction model is established. Through analysis of the characteristics of each stage of the restart-up process, an exponential decay model of restart-up pressure drop with time is created. The research results show that the variations in restart-up pressure drop with time can be divided into two stages: the attenuation stage and the equilibrium stage. The predicted value of restart-up pressure drop with time is in good agreement with the measured one, and the goodness of fit is very close to 1. The maximum restart-up pressure drop rises along with the increase in oil holdup, oil viscosity, standstill period, and water cleaning superficial velocity. The restart-up time prolongs with the increase in oil holdup, oil viscosity, and standstill period but shortens with the increase in water cleaning superficial velocity.

3.
Adv Mater ; 36(25): e2313670, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38490191

RESUMEN

The immunosuppressive tumor microenvironment (TME) is a huge hurdle in immunotherapy. Sono-immunotherapy is a new treatment modality that can reverse immunosuppressive TME, but the sonodynamic effects are compromised by overexpressed glutathione (GSH) and hypoxia in the TME. Herein, this work reports a new sono-immunotherapy strategy using Pdδ+ single atom catalysts to enhance positive sonodynamic responses to the immunosuppressive and sono-suppressive TME. To demonstrate this technique, this work employs rich and reductive Ti vacancies in Ti3-xC2Ty nanosheets to construct the atomically dispersed Pd-C3 single atom catalysts (SAC) with Pd content up to 2.5 wt% (PdSA/Ti3-xC2Ty). Compared with Pd nanoparticle loaded Ti3-xC2Ty, PdSA/Ti3-xC2Ty single-atom enzyme showed augmented sonodynamic effects that are ascribed to SAC facilitated electron-hole separation, rapid depletion of overexpressed GSH by ultrasound (US) excited holes, and catalytic decomposition of endogenous H2O2 for relieving hypoxia. Importantly, the sono-immunotherapy strategy can boost abscopal antitumor immune responses by driving maturation of dendritic cells and polarization of tumor-associated macrophages into the antitumoral M1 phenotype. Bilateral tumor models demonstrate the complete eradication of localized tumors and enhance metastatic regression. Th strategy highlights the potential of single-atom catalysts for robust sono-immunotherapy by remodeling the tumor microenvironment.


Asunto(s)
Inmunoterapia , Microambiente Tumoral , Animales , Ratones , Catálisis , Línea Celular Tumoral , Terapia por Ultrasonido/métodos , Titanio/química , Paladio/química , Glutatión/metabolismo , Glutatión/química , Humanos
4.
J Colloid Interface Sci ; 665: 681-692, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38552583

RESUMEN

The efficacy of electron-hole separation in a single sonosensitizer and the complexities of the tumor microenvironment (TME) present significant challenges to the effectiveness of sonodynamic therapy (SDT). Designing efficient sonosensitizers to enhance electron-hole separation and alleviate TME resistance is crucial yet challenging. Herein, we introduce a novel Z-scheme heterojunctions (HJs) sonosensitizer using Fe-doped carbon dots (CDs) as auxiliary semiconductors to sensitize cubic Cu2O (Fe-CDs@Cu2O) for the first time. Fe-CDs@Cu2O demonstrated enhanced SDT effects due to improved electron-hole separation. Additionally, the introduction of Fe ions in CDs synergistically enhances Fenton-like reactions with Cu ions in Cu2O, resulting in enhanced chemodynamic therapy (CDT) effects. Moreover, Fe-CDs@Cu2O exhibited rapid glutathione (GSH) depletion, effectively mitigating TME resistance. With high rates of 1O2 and OH generated by Fe-CDs@Cu2O, coupled with strong GSH depletion, single drug injection and ultrasound (US) irradiation effectively eliminate tumors. This innovative heterojunction sonosensitizer offers a promising pathway for clinical anti-tumor treatment.


Asunto(s)
Neoplasias , Microambiente Tumoral , Humanos , Carbono/farmacología , Electrones , Glutatión , Iones , Línea Celular Tumoral , Neoplasias/tratamiento farmacológico , Peróxido de Hidrógeno
5.
J Mater Chem B ; 12(3): 710-719, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38164065

RESUMEN

The main challenges of nanozyme-based tumor catalytic therapy (NCT) lie in the unsatisfactory catalytic activity accompanied by a complex tumor microenvironment (TME). A few nanozymes have been designed to possess both enzyme-like catalytic activities and photothermal properties; however, the previously reported nanozymes mainly utilize the inefficient and unsafe NIR-I laser, which has a low maximum permissible exposure limit and a limited penetration depth. Herein, we report for the first time an all-in-one strategy to realize mild NIR-II photothermally amplified NCT by synthesizing amorphous CoSnO3 nanocubes with efficient triple enzyme-like catalytic activities and photothermal conversion properties. The presence of Co2+ and Sn4+ endows CoSnO3 nanocubes with the triple enzyme-like catalytic activities, not only achieving enhanced reactive oxygen species (ROS) generation through the Co2+-mediated peroxidase-like catalytic reaction to generate ˙OH and Sn4+-mediated depletion of overexpressed GSH, but also realizing the catalytic decomposition of endogenous H2O2 for relieving tumor hypoxia. More importantly, the obtained CoSnO3 nanocubes with a high photothermal conversion efficiency of 82.1% at 1064 nm could achieve mild hyperthermia (43 °C), which further improves the triple enzyme-like catalytic activities of the CoSnO3 nanozyme. The synergetic therapeutic efficacy of the NIR-II-responsive CoSnO3 nanozyme through mild NIR-II PTT-enhanced NCT could realize all-in-one multimodal tumor therapy to completely eliminate tumors without recurrence. This study will open a new avenue to explore NIR-II-photoresponsive nanozymes for efficient tumor therapy.


Asunto(s)
Peróxido de Hidrógeno , Neoplasias , Humanos , Terapia Combinada , Catálisis , Luz , Neoplasias/tratamiento farmacológico , Microambiente Tumoral
6.
Adv Healthc Mater ; 13(2): e2302190, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37792422

RESUMEN

Although low-cost nanozymes with excellent stability have demonstrated the potential to be highly beneficial for nanocatalytic therapy (NCT), their unsatisfactory catalytic activity accompanied by intricate tumor microenvironment (TME) significantly hinders the therapeutic effect of NCT. Herein, for the first time, a heterojunction (HJ)-fabricated sonoresponsive and NIR-II-photoresponsive nanozyme is reported by assembling carbon dots (CDs) onto TiCN nanosheets. The narrow bandgap and mixed valences of Ti3+ and Ti4+ endow TiCN with the capability to generate reactive oxygen species (ROS) when exposed to ultrasound (US), as well as the dual enzyme-like activities of peroxidase and glutathione peroxidase. Moreover, the catalytic activities and sonodynamic properties of the TiCN nanosheets are boosted by the formation of HJs owing to the increased speed of carrier transfer and the enhanced electron-hole separation. More importantly, the introduction of CDs with excellent NIR-II photothermal properties could achieve mild hyperthermia (43 °C) and thereby further improve the NCT and sonodynamic therapy (SDT) performances of CD/TiCN. The synergetic therapeutic efficacy of CD/TiCN through mild hyperthermia-amplified NCT and SDT could realize "three-in-one" multimodal oncotherapy to completely eliminate tumors without recurrence. This study opens a new avenue for exploring sonoresponsive and NIR-II-photoresponsive nanozymes for efficient tumor therapy based on semiconductor HJs.


Asunto(s)
Hipertermia Inducida , Neoplasias , Humanos , Carbono , Manejo del Dolor , Peroxidasa , Peroxidasas , Neoplasias/tratamiento farmacológico , Línea Celular Tumoral , Microambiente Tumoral
7.
Adv Healthc Mater ; 13(8): e2302659, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38011489

RESUMEN

Developing next-generation antibiotics to eliminate multidrug-resistant (MDR) bacteria/fungi and stubborn biofilms is challenging, because of the excessive use of currently available antibiotics. Herein, the fabrication of anti-infection graphene quantum dots (GQDs) is reported, as a new class of topoisomerase (Topo) targeting nanoantibiotics, by modification of rich N-heterocycles (pyridinic N) at edge sites. The membrane-penetrating, nucleus-localizing, DNA-binding GQDs not only damage the cell walls/membranes of bacteria or fungi, but also inhibit DNA-binding proteins, such as Topo I, thereby affecting DNA replication, transcription, and recombination. The obtained GQDs exhibit excellent broad-spectrum antimicrobial activity against non-MDR bacteria, MDR bacteria, endospores, and fungi. Beyond combating planktonic microorganisms, GQDs inhibit the formation of biofilms and can kill live bacteria inside biofilms. RNA-seq further demonstrates the upregulation of riboflavin biosynthesis genes, DNA repair related genes, and transport proteins related genes in methicillin-resistant S. aureus (MRSA) in response to the stress induced by GQDs. In vivo animal experiments indicate that the biocompatible GQDs promote wound healing in MRSA or C. albicans-infected skin wound models. Thus, GQDs may be a promising antibacterial and antifungal candidate for clinical applications in treating infected wounds and eliminating already-formed biofilms.


Asunto(s)
Antiinfecciosos , Grafito , Staphylococcus aureus Resistente a Meticilina , Puntos Cuánticos , Animales , Grafito/química , Puntos Cuánticos/química , Antibacterianos/química
8.
Sci Rep ; 13(1): 4051, 2023 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-36899027

RESUMEN

In radiotherapy, air-filled ion chamber detectors are ubiquitously used in routine dose measurements for treatment planning. However, its use has been restricted by intrinsic low spatial resolution barriers. We developed one procedure for patient-specific quality assurance (QA) in arc radiotherapy by coalescing two adjacent measurement images into a single image to improve spatial resolution and sampling frequency, and investigated how different spatial resolutions affect the QA results. PTW 729 and 1500 ion chamber detectors were used for dosimetric verification via coalescing two measurements with 5 mm-couch shift and the isocenter, and only isocenter measurement, which we call coalescence and standard acquisition (SA). Statistical process control (SPC), process capability analysis (PCA), and receiver operating characteristic (ROC) curve were used to compare the performance of the two procedures in determining tolerance levels and identifying clinically relevant errors. By analyzing 1256 γ values calculated on interpolated data points, our results indicated that detector 1500 showed higher averages in coalescence cohorts at different tolerance criteria and the dispersion degrees were spread out smaller. Detector 729 yielded a slightly lower process capability of 0.79, 0.76, 1.10, and 1.34, but detector 1500 exhibited somewhat different results of 0.94, 1.42, 1.19, and 1.60 in magnitude. The results of SPC individual control chart showed that cases in coalescence cohorts with γ values lowering its lower control limit (LCL) were greater than those in SA cohorts for detector 1500. A combination of the width of multi-leaf collimator (MLC) leaf, the cross-sectional area of the single detector, and the spacing between adjacent detectors might lead to discrepancies in percent γ values across diverse spatial resolution scenarios. The accuracy of reconstructed volume dose is mainly determined by the interpolation algorithm used in dosimetric systems. The magnitude of filling factor in the ion chamber detectors determined its ability to detect dose deviations. SPC and PCA results indicated that coalescence procedure could detect more potential failure QA results than SA while enhancing action thresholds.


Asunto(s)
Radioterapia de Intensidad Modulada , Humanos , Radioterapia de Intensidad Modulada/métodos , Radiometría/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Algoritmos , Dosificación Radioterapéutica
9.
Front Public Health ; 11: 1121154, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36741947

RESUMEN

Green credit plays an important role in environmental protection and residents' health. This paper discusses the impact path of green credit on social health costs with the help of a quantile regression. The implementation of a green credit policy can decrease social health costs in China, and green credit works best in the economically developed Eastern region. As the quantile increases, so gradually does the absolute value of the green credit coefficient. This result proves that for provinces with rich per capita financial health expenditures, green credit plays a greater role in decreasing social costs, a conclusion also supported by our robustness test. In addition, we find that environmental pollution plays a mediating role in the path of green credit affecting health, and this finding is verified in the green credit and health general equilibrium model. Based on these findings, the government should encourage the active innovation of green credit products, and the banking industry should develop personalized green credit products for specific pollutant types or industries while decreasing government pressure.


Asunto(s)
Costos de la Atención en Salud , Gastos en Salud , China , Contaminación Ambiental , Gobierno
10.
Appl Radiat Isot ; 192: 110567, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36459899

RESUMEN

PURPOSE: To investigate the error detectability limitations of an EPID-based 3D in vivo dosimetry verification system for lung stereotactic body radiation therapy (SBRT). METHODS: Thirty errors were intentionally introduced, consisting of dynamic and constant machine errors, to simulate the possible errors that may occur during delivery. The dynamic errors included errors in the output, gantry angle and MLC positions related to gantry inertial and gravitational effects, while the constant errors included errors in the collimator angle, jaw positions, central leaf positions, setup shift and thickness to simulate patient weight loss. These error plans were delivered to a CIRS phantom using the SBRT technique for lung cancer. Following irradiation of these error plans, the dose distribution was reconstructed using iViewDose™ and compared with the no error plan. RESULTS: All errors caused by the central leaf positions, dynamic MLC errors, Jaw inwards movements, setup shifts and patient anatomical changes were successfully detected. However, dynamic gantry angle and collimator angle errors were not detected in the lung case due to the rotation-symmetric target shape. The results showed that the γmean and γpassrate indicators can detect 13 (81.3%) and 14 (87.5%) of the 16 errors respectively without including the gantry angle error, collimator angle error and output error. CONCLUSIONS: In summary, iViewDose™ is an appropriate approach for detecting most types of clinical errors for lung SBRT. However, the phantom results also showed some detectability limitations of the system in terms of dynamic gantry angle and constant collimator angle errors.


Asunto(s)
Neoplasias Pulmonares , Radiocirugia , Radioterapia de Intensidad Modulada , Humanos , Radioterapia de Intensidad Modulada/métodos , Pulmón , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/radioterapia , Planificación de la Radioterapia Asistida por Computador , Dosificación Radioterapéutica , Radiometría
11.
Nat Commun ; 13(1): 5735, 2022 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-36175446

RESUMEN

Theranostic sonosensitizers with combined sonodynamic and near infrared (NIR) imaging modes are required for imaging guided sonodynamic therapy (SDT). It is challenging, however, to realize a single material that is simultaneously endowed with both NIR emitting and sonodynamic activities. Herein, we report the design of a class of NIR-emitting sonosensitizers from a NIR phosphorescent carbon dot (CD) material with a narrow bandgap (1.62 eV) and long-lived excited triplet states (11.4 µs), two of which can enhance SDT as thermodynamically and dynamically favorable factors under low-intensity ultrasound irradiation, respectively. The NIR-phosphorescent CDs are identified as bipolar quantum dots containing both p- and n-type surface functionalization regions that can drive spatial separation of e--h+ pairs and fast transfer to reaction sites. Importantly, the cancer-specific targeting and high-level intratumor enrichment of the theranostic CDs are achieved by cancer cell membrane encapsulation for precision SDT with complete eradication of solid tumors by single injection and single irradiation. These results will open up a promising approach to engineer phosphorescent materials with long-lived triplet excited states for sonodynamic precision tumor therapy.


Asunto(s)
Carbono , Puntos Cuánticos , Encapsulación Celular , Membrana Celular , Luz
12.
Emerg Med Int ; 2022: 1251388, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36119913

RESUMEN

Objective: This paper aims to explore the use of computer-based simulation teaching combined with PBL in colorectal tumor bleeding. Methods: The outpatient department organized 21 nursing staffs to conduct computer simulation combined with PBL teaching, compared emergency theory and skill scores, and investigated the recognition of computer simulation teaching combined with PBL. Results: The scores of theoretical knowledge examination before training were (84.31 ± 6.39) and (92.59 ± 2.93) after training; the scores of treatment skills examination were (85.69 ± 6.15) and (95.43 ± 2.88) after training; the scores of comprehensive treatment skills before training were (76.6 ± 6.31) and (91.43 ± 2.3) after training. The results of the questionnaires showed that the nurses were more agreeable to the new teaching methods and were able to complete the tasks in strict accordance with the requirements, ultimately achieving a level of satisfaction with their progress. Conclusion: Computer simulation teaching combined with PBL can deepen general practitioners' understanding of knowledge, improve practical ability, and provide a clinical basis for improving patient resuscitation in specialized oncology hospitals.

13.
J Mater Chem B ; 10(17): 3357-3365, 2022 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-35380572

RESUMEN

Developing efficient therapeutic strategies for combating bacterial infection remains a challenge owing to the indiscriminate utilization of antibiotics and the prevalence of multidrug-resistant (MDR) bacteria. Herein, highly graphitic-N-doped graphene quantum dots (N-GQDs) with efficient NIR-II photothermal conversion properties were synthesized for the first time for photothermal antibacterial therapy. The obtained N-GQDs exhibited strong NIR absorption ranging from 700 to 1200 nm, achieving high photothermal conversion efficiency of 77.8% and 50.4% at 808 and 1064 nm, respectively. Outstanding antibacterial and antibiofilm activities against MDR bacteria (methicillin-resistant Staphylococcus aureus, MRSA) were achieved by the N-GQDs in the presence of an 808 or 1064 nm laser. In vivo investigations verified that the generation of hyperthermia by N-GQDs plus a NIR-II laser can combat MDR bacterial infections and thus significantly accelerate wound healing. Our work provides a novel carbon-based nanomaterial as a photothermal antibacterial agent for efficiently avoiding bacterial resistance and fighting MDR bacterial infections.


Asunto(s)
Grafito , Staphylococcus aureus Resistente a Meticilina , Puntos Cuánticos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana Múltiple , Grafito/farmacología
14.
Environ Sci Pollut Res Int ; 29(26): 39638-39648, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35107732

RESUMEN

It is necessary to effectively separate photocatalytic materials from water bodies and reuse catalysts for industrial wastewater treatment. Herein, a novel nanofiber membrane with enhanced light absorption and reusability of photocatalytic materials was prepared. The three-dimensional porous structure of the nanofibers helps the photocatalyst efficiently degrade pollutants. Specifically, a high-efficiency photocatalyst carrier with a nanofiber structure (PAN/PU/ß-CD@Ag nanofiber membrane) was prepared by electrospinning and a simple silver plating process, and then ZnO NPs were synthesized in situ on the nanofiber membrane during the hydrothermal process. Under visible-light irradiation, the ZnO-loaded PAN/PU/ß-CD@Ag nanofiber membranes exhibited excellent photocatalytic performance for the degradation of methylene blue (MB, 71.5%) and tetracycline hydrochloride (TCH, 70.5%). Additionally, a possible pathway of charge migration in this system was proposed. This design may provide a new idea for the preparation of visible-light photocatalytic nanofiber membranes and their treatments of wastewater containing dyes and hormones.


Asunto(s)
Nanofibras , Óxido de Zinc , Catálisis , Nanofibras/química , Semiconductores , Plata/química , Óxido de Zinc/química
15.
Front Psychol ; 13: 972992, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36605283

RESUMEN

Introduction: The entrepreneurship rate of Chinese college students is relatively low. This study investigates the environment factors that influence college students' entrepreneurial intention as mediated by personality traits. Methods: According to the entrepreneurial ecosystem theory, a hierarchical model of the environment factors was established which included three layers: personality traits as the micro system, family and education as the meso system, and social and policy support as the macro system. The structural equation model of the environment factors was constructed to reveal the significant influence path of various factors and the mediating role of personality traits. Data were collected from 436 undergraduate students in Henan Province, China. Results: Findings indicate that family, education, social, and policy factors have no significant direct influence on entrepreneurial intention. However, personality traits significantly influence entrepreneurial intention and mediate the effects of various factors on entrepreneurial intention. Discussion: Suggestions such as improving college students' entrepreneurial practice and promoting college students' proactive personalities are also put forward.

16.
Artículo en Inglés | MEDLINE | ID: mdl-32427053

RESUMEN

Understanding the physicochemical characteristics of oil-based cuttings (OBCs) is an important foundation for subsequent treatment and management. The macro- and microscopic properties of white oil-based cuttings (WOBCs) and diesel-based cuttings (DBCs) after the different pretreatment steps have been assessed using scanning electron microscopy. The organic and inorganic compositions of OBCs have been analyzed using X-ray diffraction, Fourier-transform infrared spectrometry, and gas chromatography-mass spectrometry. Inorganic matter (SiO2, BaSO4, and CaCO3), alkanes, aromatic compounds, and water were the main components of OBCs. The organic content (26.14%) and alkane content of the WOBCs were higher than that of the DBCs, whereas for the inorganic content (70.87%), the reverse was true. The macro- and micromorphologies of OBCs were quite different because their oil and water contents were different. The oil contents of OBCs decreased in the order A1 (14.64%) > A3 (12.67%) > A2 (11.06%) and B1 (9.19%) > B3 (8.94%) > B2 (4.66%); the water contents decreased in the order A1 (2.99%) > A3 (2.19%) > A2 (1.09%) and B1 (2.30%) > B3 (1.87%) > B2 (1.09%). Moreover, a skid-mounted treatment technology for OBCs was proposed. The results can be a scientific guidance for the treatment and management of OBCs.


Asunto(s)
Sustancias Peligrosas/química , Compuestos Inorgánicos/química , Aceite Mineral/química , Yacimiento de Petróleo y Gas/química , Hidrocarburos Policíclicos Aromáticos/química , Purificación del Agua/métodos , Fenómenos Químicos , Cromatografía de Gases y Espectrometría de Masas , Sustancias Peligrosas/análisis , Compuestos Inorgánicos/análisis , Aceite Mineral/análisis , Gas Natural/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Aguas Residuales/análisis , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química
17.
Eng Life Sci ; 19(11): 815-824, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32624974

RESUMEN

In this study, 2-hydroxyethyl methacrylate (HEMA) was used as the monomers for surface grafting on electrospun PU/RC nanofiber membrane via atom transfer radical polymerization (ATRP) method, and the PU/RC-poly(HEMA) nanofiber membrane was investigated as a carrier for LAC. Free and immobilized LAC was characterized, and efficiency of bisphenol A (BPA) removal was determined. The results indicated that the PU/RC-poly(HEMA)-LAC showed relatively higher pH stability, temperature stability, and storage stability than free and PU/RC-LAC; moreover, more than 60% of the PU/RC-poly(HEMA)-LAC activity was retained after 10 cycles of ABTS treatment. Notably, the BPA removal efficiency of PU/RC-poly(HEMA)-LAC membrane generally ranged from 87.3 to 75.4% for the five cycles. Therefore, the PU/RC-poly(HEMA) nanofiber membrane has great potential as a carrier for the LAC immobilization for various industrial applications and bioremediation.

18.
Sci Adv ; 4(3): eaao1761, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29511734

RESUMEN

Quinones, which are ubiquitous in nature, can act as sustainable and green electrode materials but face dissolution in organic electrolytes, resulting in fast fading of capacity and short cycle life. We report that quinone electrodes, especially calix[4]quinone (C4Q) in rechargeable metal zinc batteries coupled with a cation-selective membrane using an aqueous electrolyte, exhibit a high capacity of 335 mA h g-1 with an energy efficiency of 93% at 20 mA g-1 and a long life of 1000 cycles with a capacity retention of 87% at 500 mA g-1. The pouch zinc batteries with a respective depth of discharge of 89% (C4Q) and 49% (zinc anode) can deliver an energy density of 220 Wh kg-1 by mass of both a C4Q cathode and a theoretical Zn anode. We also develop an electrostatic potential computing method to demonstrate that carbonyl groups are active centers of electrochemistry. Moreover, the structural evolution and dissolution behavior of active materials during discharge and charge processes are investigated by operando spectral techniques such as IR, Raman, and ultraviolet-visible spectroscopies. Our results show that batteries using quinone cathodes and metal anodes in aqueous electrolyte are reliable approaches for mass energy storage.

19.
Comput Math Methods Med ; 2015: 454638, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25873988

RESUMEN

The study of various living complex systems by system identification method is important, and the identification of the problem is even more challenging when dealing with a dynamic nonlinear system of discrete time. A well-established model based on kernel functions for input of the maximum length sequence (m-sequence) can be used to estimate nonlinear binary kernel slices using cross-correlation method. In this study, we examine the relevant mathematical properties of kernel slices, particularly their shift-and-product property and overlap distortion problem caused by the irregular shifting of the estimated kernel slices in the cross-correlation function between the input m-sequence and the system output. We then derive the properties of the inverse repeat (IR) m-sequence and propose a method of using IR m-sequence as an input to separately estimate odd- and even-order kernel slices to reduce the chance of kernel-slice overlapping. An instance of third-order Wiener nonlinear model is simulated to justify the proposed method.


Asunto(s)
Simulación por Computador , Dinámicas no Lineales , Algoritmos , Biología Computacional , Distribución Normal , Programas Informáticos , Biología de Sistemas
20.
Sci Rep ; 4: 3600, 2014 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-24398592

RESUMEN

Transformation thermodynamics, as one of the important branches among the extensions of transformation optics, has attracted plentiful attentions and interests recently. The result of transformation thermodynamics, or called as "thermal cloak", can realize isothermal region and hide objects from heat. In this paper, we presented the concept of "reverse thermal cloak" to correspond to the thermal cloak and made a simple engineering definition to identify them. By full-wave simulations, we verified that the reverse thermal cloak can concentrate heat and realize local heating. The performance of local heating depends on the anisotropic dispersion of the cloaking layer's thermal conductivity. Three-dimensional finite element simulations demonstrated that the reverse thermal cloak can be used to heat up objects. Besides pre-engineered metamaterials, such reverse thermal cloak can even be realized with homogenous materials by alternating spoke-like structure or Hashin coated-sphere structure.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...