Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Small ; 19(49): e2303498, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37607318

RESUMEN

Achieving rapid and effective hemostasis remains a multidisciplinary challenge. Here, distinctive functional carbon dots derived from carbonized Platycladus orientalis (CPO-CDs) are developed using one-step hydrothermal method. The negatively charged surface of CPO-CDs retains partial functional groups from CPO precursor, exhibiting excellent water solubility and high biocompatibility. Both rat liver injury model and tail amputation model have confirmed the rapid and effective hemostatic performance of CPO-CDs on exogenous hemorrhage. Further, on endogenous blood-heat hemorrhage syndrome rat model, CPO-CDs could inhibit hemorrhage and alleviate inflammation response. Interestingly, the excellent hemostasis performance of CPO-CDs is ascribed to activate exogenous coagulation pathway and common coagulation pathway. More importantly, metabolomics of rat plasma suggests that the hemostasis effect of CPO-CDs is closely related to platelet functions. Therefore, the designed in vitro experiments are performed and it is discovered that CPO-CDs significantly promote platelets adhesion, activation, and aggregation. Further, the underlying mechanism investigation suggests that Src/Syk signal pathway plays a key role in platelets activation triggered by CPO-CDs. Overall, CPO-CDs with rapid and excellent hemostatic performance are discovered for the first time, which could be an excellent candidate for the treatment of hemorrhagic diseases.


Asunto(s)
Carbono , Hemostáticos , Ratas , Animales , Carbono/farmacología , Coagulación Sanguínea , Hemostasis , Plaquetas/metabolismo , Hemostáticos/farmacología , Hemorragia/metabolismo
2.
Small ; 19(50): e2304634, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37626464

RESUMEN

Suppressing the photoelectric response of organic semiconductors (OSs) is of great significance for improving the operational stability of organic field-effect transistors (OFETs) in light environments, but it is quite challenging because of the great difficulty in precisely modulating exciton dynamics. In this work, photostable OFETs are demonstrated by designing the micro-structure of OSs and introducing an electrical double layer at the OS/polyelectrolyte dielectric interface, in which multiple exciton dynamic processes can be modulated. The generation and dissociation of excitons are depressed due to the small light-absorption area of the microstripe structure and the excellent crystallinity of OSs. At the same time, a highly efficient exciton quenching process is activated by the electrical double layer at the OS/polyelectrolyte dielectric interface. As a result, the OFETs show outstanding tolerance to the light irradiation of up to 306 mW·cm-2 , which far surpasses the solar irradiance value in the atmosphere (≈138 mW·cm-2 ) and achieves the highest photostability ever reported in the literature. The findings promise a general and practicable strategy for the realization of photostable OFETs and organic circuits.

3.
J Environ Manage ; 311: 114870, 2022 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-35279487

RESUMEN

In order to achieve the targets specified in the Action Plan for Air Pollution Prevention and Control (APAPPC), a limited coal banning area (10,000 km2) was designated in the heavily polluted Beijing-Tianjin-Hebei region (BTH) for the first time in 2017. PM2.5 and elements were sampled by the network of BTH to evaluate the effectiveness of this policy. This study found that the fine days with PM2.5 < 75 µg m-3 accounted for 74.3% in the autumn and winter of 2017, which was significantly higher than that in 2016 (43%). The heavily polluted days (PM2.5 > 150 µg m-3) also decreased from 32.2% in 2016 to 4.9% in 2017. Arsenic (As) is an important tracer in coal consumption, which can be used to reflect the influence of the establishment of coal banning areas on north China. The cluster analysis of air mass forward trajectory identified that the number of polluted trajectories with PM2.5 and As in 2017 decreased by 47.6% and 49.7%, respectively. Under the implementation of the coal banning policy, the weighted concentration of PM2.5 and As decreased by 94.2 µg m-3 and 5.1 ng m-3 in the coal banning area, 60.9 µg m-3 and 3.4 ng m-3 in the no coal banning area in BTH, respectively. The influence of weighted concentration of PM2.5 and As in coal banning area on North China were 1.6-49.2 µg m-3 and 0.15-2.8 ng m-3, respectively, which was 38.8% and 29.7% lower than 2016. In coal banning area, BTH and other parts of North China, the reduction of the weight concentration of PM2.5 in 2017 accounted for 41.4%, 26.8% and 31.8% of the total reduction, respectively, so was the As in 39%, 26.3% and 34.6%, indicating that setting up a coal banning area scientifically in limited areas can produce remarkable regional benefit.

4.
Molecules ; 27(22)2022 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-36431859

RESUMEN

Toad venom, a dried product of secretion from Bufo bufo gargarizans Cantor or Bufo melanostictus Schneider, has had the therapeutic effects of hepatocellular carcinoma confirmed. Bufalin and cinobufagin were considered as the two most representative antitumor active components in toad venom. However, the underlying mechanisms of this antitumor effect have not been fully implemented, especially the changes in endogenous small molecules after treatment. Therefore, this study was designed to explore the intrinsic mechanism on hepatocellular carcinoma after the cotreatment of bufalin and cinobufagin based on untargeted tumor metabolomics. Ultraperformance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) was performed to identify the absorbed components of toad venom in rat plasma. In vitro experiments were determined to evaluate the therapeutic effects of bufalin and cinobufagin and screen the optimal ratio between them. An in vivo HepG2 tumor-bearing nude mice model was established, and a series of pharmacodynamic indicators were determined, including the body weight of mice, tumor volume, tumor weight, and histopathological examination of tumor. Further, the entire metabolic alterations in tumor after treating with bufalin and cinobufagin were also profiled by UHPLC-MS/MS. Twenty-seven active components from toad venom were absorbed in rat plasma. We found that the cotreatment of bufalin and cinobufagin exerted significant antitumor effects both in vitro and in vivo, which were reflected in inhibiting proliferation and inducing apoptosis of HepG2 cells and thereby causing cell necrosis. After cotherapy of bufalin and cinobufagin for twenty days, compared with the normal group, fifty-six endogenous metabolites were obviously changed on HepG2 tumor-bearing nude mice. Meanwhile, the abundance of α-linolenic acid and phenethylamine after the bufalin and cinobufagin intervention was significantly upregulated, which involved phenylalanine metabolism and α-linolenic acid metabolism. Furthermore, we noticed that amino acid metabolites were also altered in HepG2 tumor after drug intervention, such as norvaline and Leu-Ala. Taken together, the cotreatment of bufalin and cinobufagin has significant antitumor effects on HepG2 tumor-bearing nude mice. Our work demonstrated that the in-depth mechanism of antitumor activity was mainly through the regulation of phenylalanine metabolism and α-Linolenic acid metabolism.


Asunto(s)
Venenos de Anfibios , Carcinoma Hepatocelular , Neoplasias Hepáticas , Ratas , Ratones , Animales , Carcinoma Hepatocelular/tratamiento farmacológico , Ratones Desnudos , Espectrometría de Masas en Tándem , Ácido alfa-Linolénico , Neoplasias Hepáticas/tratamiento farmacológico , Venenos de Anfibios/farmacología , Venenos de Anfibios/química , Bufonidae , Fenilalanina
5.
Chemistry ; 27(48): 12341-12351, 2021 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-34196056

RESUMEN

Searching for novel anode materials to address the issues of poor cycle stability in the aqueous lithium-ion battery system is highly desirable. In this work, ammonium vanadium bronze (NH4 )2 V7 O16 with brick-like morphology has been investigated as an anode material for aqueous lithium-ion batteries and Li+ /Na+ hybrid ion batteries. The two novel full cell systems (NH4 )2 V7 O16 ||Li2 SO4 ||LiMn2 O4 and (NH4 )2 V7 O16 ||Na2 SO4 ||LiMn2 O4 both demonstrate good rate capability and excellent cycling performance. A capacity retention of 78.61 % after 500 cycles at 300 mA g-1 was demonstrated in the (NH4 )2 V7 O16 ||Li2 SO4 ||LiMn2 O4 system, whereas no capacity attenuation is observed in the (NH4 )2 V7 O16 ||Na2 SO4 ||LiMn2 O4 system. The reaction mechanisms of the (NH4 )2 V7 O16 electrode and impedance variation of the two full cells were also researched. The excellent cycling stability suggests that layered (NH4 )2 V7 O16 can be a promising anode material for aqueous rechargeable lithium-ion batteries.

6.
Nano Lett ; 20(10): 7342-7349, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-32877198

RESUMEN

Two-dimensional carbon architectures are attracting tremendous interests for various promising applications due to their outstanding electronic and mechanical properties, although it is a great challenge to rationally devise facile and operative methodologies to engineer their structural traits owing to complex synthetic processes. Herein, for the first time, we fabricate two-dimensional carbon nanoribbons via direct thermal exfoliation of one-dimensional Ni-based metal-organic framework (MOF) nanorods, in which interconnected graphitic carbon nanocages are self-assembled into a belt-like superstructure with carbon-encapsulated Ni nanoparticles immobilized on the surface. Due to the unparalleled structural superiority, the MOF-derived carbon nanobelts exhibit excellent catalytic performances in electrocatalytic hydrogen evolution. Importantly, the practical synthetic strategy may trigger the rapid development of carbon-based superstructures in many frontier fields.

7.
Analyst ; 145(6): 2311-2318, 2020 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-32021993

RESUMEN

Fingerprints remain topologically unchanged in one's whole life, and therefore, have been used as a means to biometrically identify individuals in forensic investigations, law enforcement and access control. Appropriate methods are essential to obtain high-quality fingerprint images. In this contribution, an aggregation-induced emission luminogen tetraphenylethene-based dye FLA-2 was synthesized and characterized for the visualization of latent fingerprints (LFPs). LFPs can be directly visualized by incubating with the dye FLA-2 solution. And, after a cyanoacrylate fuming method pre-treatment stage, fine fingerprint structures can be obtained from level-1 to level-3 details. Two methods were compared using resolution, fluorescence intensity, and scanning electron microscopy imaging to investigate the influence of the cyanoacrylate fuming method pre-treatment stage. Furthermore, the visualization of old LFPs (7 d, 16 d and 30 d) on glass slides, aluminum foil and coin substrates also became effective after the pre-treatment step. The fluorescent LFP images mentioned above were all validated by using an automated fingerprint identification system obtaining positive matches. These results demonstrate the potential of this method to be applied to visualizing LFPs in the field of public security.

8.
Global Health ; 15(1): 7, 2019 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-30670067

RESUMEN

BACKGROUND: Reducing premature deaths is an important step towards achieving the World Health Organization's sustainable development goal. Redeployed miners are more prone to disease or premature death due to the special occupational characteristics. Our aims were to describe the deaths of redeployed miners, assess the losses due to premature death and identify their main health problems. All the records of individuals were obtained from Fuxin Mining Area Social Security Administration Center. Year of life lost (YLL) and average year of life lost were used to assess the loss due to premature death. YLL rates per 1000 individuals were considered to compare deaths from different populations. RESULTS: Circulatory system diseases contributed the most years of life lost in the causes of death, followed by neoplasms. But average year of life lost in neoplasms was 6.85, higher than circulatory system diseases, 5.63. Cerebrovascular disease and ischemic heart disease were the main causes of death in circulatory system diseases. And average years of life lost in cerebrovascular disease and ischemic heart disease were 5.85 and 5.62, higher than those in other circulatory system diseases. Lung cancer was the principal cause of death in neoplasms. Average year of life lost in liver cancer was 7.92, the highest in neoplasms. CONCLUSIONS: For redeployed miners, YLL rates per 1000 individuals in cerebrovascular disease, ischemic heart disease and lung cancer were higher than those in other populations, especially in men. It is important to attach importance to the health of redeployed miners, take appropriate measures to reduce premature death and achieve the sustainable development goal. Our findings also contribute to a certain theoretical reference for other countries that face or will face the same problem.


Asunto(s)
Minería , Mortalidad Prematura , Enfermedades no Transmisibles/mortalidad , Enfermedades Profesionales/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Causas de Muerte , China/epidemiología , Femenino , Humanos , Esperanza de Vida , Masculino , Persona de Mediana Edad
9.
Chemistry ; 23(53): 13221-13232, 2017 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-28771852

RESUMEN

Nanorods of δ-Ca0.24 V2 O5 ⋅H2 O, a straczekite group mineral with an open double-layered structure, have been successfully fabricated by a facile hydrothermal method and can be transformed into the tunnel ß geometry (ß-Ca0.24 V2 O5 ) through a vacuum annealing treatment. The generated ß-Ca0.24 V2 O5 still preserves the nanorod construction of δ-Ca0.24 V2 O5 ⋅H2 O without substantial sintering and degradation of the nanostructure. As cathode materials, both calcium vanadium bronzes exhibit high reversible capacity, good rate capability, as well as superior cyclability. Compared with the hydrated vanadium bronze, the ß-Ca0.24 V2 O5 nanorods show better cycling performance (81.68 and 97.93 % capacity retention after 200 cycles at 100 and 400 mA g-1 , respectively) and excellent long-term cyclic stability with an average decay of 0.035 % per cycle over 500 cycles at 500 mA g-1 . Note that the double-layered δ-Ca0.24 V2 O5 ⋅H2 O electrode irreversibly converts into ß-Cax V2 O5 phase during the initial Li+ insertion/extraction process, while in contrast, the ß-phase calcium vanadium bronze electrode shows excellent structural stability during cycling. The excellent electrochemical performance demonstrates that the two calcium vanadium bronzes are potential cathode candidates for rechargeable lithium-ion batteries.

10.
Artículo en Inglés | MEDLINE | ID: mdl-38598396

RESUMEN

Opponent modeling has proven effective in enhancing the decision-making of the controlled agent by constructing models of opponent agents. However, existing methods often rely on access to the observations and actions of opponents, a requirement that is infeasible when such information is either unobservable or challenging to obtain. To address this issue, we introduce distributional opponent-aided multiagent actor-critic (DOMAC), the first speculative opponent modeling algorithm that relies solely on local information (i.e., the controlled agent's observations, actions, and rewards). Specifically, the actor maintains a speculated belief about the opponents using the tailored speculative opponent models that predict the opponents' actions using only local information. Moreover, DOMAC features distributional critic models that estimate the return distribution of the actor's policy, yielding a more fine-grained assessment of the actor's quality. This thus more effectively guides the training of the speculative opponent models that the actor depends upon. Furthermore, we formally derive a policy gradient theorem with the proposed opponent models. Extensive experiments under eight different challenging multiagent benchmark tasks within the MPE, Pommerman, and starcraft multiagent challenge (SMAC) demonstrate that our DOMAC successfully models opponents' behaviors and delivers superior performance against state-of-the-art (SOTA) methods with a faster convergence speed.

11.
Clin Chim Acta ; 548: 117513, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37562523

RESUMEN

BACKGROUND: Thyroid-stimulating hormone (TSH) is measured differently between diagnostic units using different devices, which makes cross-comparisons challenging. Here, we have developed a mathematical algorithm to harmonize TSH measurements between 2 instruments, the Abbott ISR2000 and the Siemens ADVIA Centaur XP. METHODS: Applying the principle of the maximum allowable error between the standard curve and real signal values, the minimum number of comparison samples required for TSH hormone detection was calculated for both instruments. Next, a mathematical algorithm describing the relationship between TSH standard curves from both instruments was established. The algorithm was then tested on sample measurements from both instruments, with signals transformed to Siemens ADVIA Centuar XP-type data. Finally, test results were assessed where the relative error was 1/2 TEa). After algorithmic transformation, the average percentage error was reduced to 7.93% (<1/2 TEa). CONCLUSIONS: Our algorithm enables TSH measurements across different instruments to be comparable, and provides a method to harmonize TSH data between laboratories that utilize different instrumentation.


Asunto(s)
Algoritmos , Tirotropina , Humanos
12.
J Phys Act Health ; 20(6): 500-507, 2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-37024106

RESUMEN

BACKGROUND: This study aimed to assess physical activity level and identify specific types of exercises by sex, race/ethnicity, and age for adults 50 years and older. METHODS: Behavioral Risk Factor Surveillance System 2013, 2015, and 2017 data were used to study US adults 50 years and older on their specific types of exercises, stratified by sex, race/ethnicity, and age. Weighted logistic regression was used to model physical exercise level and specific types of exercises. RESULTS: The sample included 460,780 respondents. Non-Hispanic Black and Hispanic were less likely than non-Hispanic White to meet the recommended physical activity level (Odds ratio [OR] = 0.73, P < .0001 and OR = 0.96, P = .04, respectively). Walking was the most participated type of exercise, followed by gardening, for both men and women, all racial/ethnic groups, and all age groups. Non-Hispanic Blacks were more likely to participate in walking (OR = 1.19, P = .02) and less likely to participate in gardening (OR = 0.65, P < .0001) than non-Hispanic Whites. Men were more likely to engage in strenuous exercises than women. The average number of minutes on walking was the longest among all types of specific exercises. CONCLUSIONS: The types of exercises were mostly walking and gardening for adults aged 50 and older. Non-Hispanic Black adults had less physical activity than non-Hispanic White and were less likely to engage in gardening.


Asunto(s)
Etnicidad , Ejercicio Físico , Masculino , Persona de Mediana Edad , Humanos , Femenino , Estados Unidos , Anciano , Factores de Riesgo , Encuestas y Cuestionarios , Blanco
13.
Artículo en Inglés | MEDLINE | ID: mdl-37352084

RESUMEN

While the encoder-decoder structure is widely used in the recent neural construction methods for learning to solve vehicle routing problems (VRPs), they are less effective in searching solutions due to deterministic feature embeddings and deterministic probability distributions. In this article, we propose the feature embedding refiner (FER) with a novel and generic encoder-refiner-decoder structure to boost the existing encoder-decoder structured deep models. It is model-agnostic that the encoder and the decoder can be from any pretrained neural construction method. Regarding the introduced refiner network, we design its architecture by combining the standard gated recurrent units (GRU) cell with two new layers, i.e., an accumulated graph attention (AGA) layer and a gated nonlinear (GNL) layer. The former extracts dynamic graph topological information of historical solutions stored in a diversified solution pool to generate aggregated pool embeddings that are further improved by the GRU, and the latter adaptively refines the feature embeddings from the encoder with the guidance of the improved pool embeddings. To this end, our FER allows current neural construction methods to not only iteratively refine the feature embeddings for boarder search range but also dynamically update the probability distributions for more diverse search. We apply FER to two prevailing neural construction methods including attention model (AM) and policy optimization with multiple optima (POMO) to solve the traveling salesman problem (TSP) and the capacitated VRP (CVRP). Experimental results show that our method achieves lower gaps and better generalization than the original ones and also exhibits competitive performance to the state-of-the-art neural improvement methods.

14.
ACS Appl Mater Interfaces ; 15(41): 47939-47954, 2023 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-37791782

RESUMEN

Astragalus membranaceus (Fisch.) Bge. (AM) and Angelica sinensis (Oliv.) Diels (AS) constitute a classic herb pair in prescriptions to treat myocardial fibrosis. To date, research on the AM-AS herb pair has mainly focused on the chemical compositions associated with therapeutic efficacy. However, supermolecules actually exist in herb codecoctions, and their self-assembly mechanism remains unclear. In this study, supermolecules originating from AM-AS codoping reactions (AA-NPs) were first reported. The chemical compositions of AA-NPs showed a dynamic self-assembly process. AA-NPs with different decoction times had similar surface groups and amorphous states; however, the size distributions of these nanoparticles might be different. Taking the interaction between Z-ligustilide and astragaloside IV as an example to understand the self-assembly mechanism of AA-NPs, it was found that the complex could be formed with a molar ratio of 2:1. Later, AA-NPs were proven to be effective in the treatment of myocardial fibrosis both in vivo and in vitro, the in-depth mechanisms of which were related to the recovery of cardiac function, reduced collagen deposition, and inhibition of the endothelial-to-mesenchymal transition that occurred in the process of myocardial fibrosis. Thus, AA-NPs may be the chemical material basis of the molecular mechanism of the AM-AS decoction in treating isoproterenol-induced myocardial fibrosis. Taken together, this work provides a supramolecular strategy for revealing the interaction between effective chemical components in herb-pair decoctions.


Asunto(s)
Angelica sinensis , Medicamentos Herbarios Chinos , Astragalus propinquus/química , Angelica sinensis/química , Medicamentos Herbarios Chinos/química , Fibrosis
15.
ACS Appl Bio Mater ; 6(10): 4358-4371, 2023 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-37702706

RESUMEN

To overcome the intestinal epithelium barrier and achieve a better antitumor effect, the procedurally targeting flower-like nanomicelles for oral delivery of antitumor drugs were designed based on FAPα-responsive TPGS1000 dimer (TPGS-Gly-Pro-TPGS) and L-carnitine linked poly(2-ethyl-2-oxazoline)-b-poly(D, l-lactide) (Car-PEOz-b-PLA). As expected, compared with unmodified polymeric micelles (TT-PMs) composed of TPGS-Gly-Pro-TPGS, L-carnitine conjugated polymeric micelles (CTT-PMs) formed from both TPGS-Gly-Pro-TPGS and Car-PEOz-b-PLA with favorable stability in simulated gastrointestinal fluid and FAPα-dependent release capability exhibited remarkably enhanced cellular uptake and transmembrane transport through OCTN2 mediation confirmed by fluorescence immunoassay, which was intuitively evidenced by stronger fluorescence within epithelial cells, and the basal side of small intestinal epithelium of mice being given intragastric administration of DiI-labeled micelles. The transport of CTT-PMs across the intestinal epithelium in an intact form was mediated by clathrin along the intracellular transport pathway of endosome-lysosome-ER-Golgi apparatus. Furthermore, both the increased uptake by FAPα-positive U87MG cells and unchangeable uptake by FAPα-negative C6 cells for coumarin-6 (C-6)/CTT-PMs compared with C-6/TT-PMs evidenced the targeting ability of CTT-PMs to FAPα-positive tumor cells. Both OCTN2-mediation and FAPα-responsiveness were beneficial for polymeric micelles to improve the delivery and therapeutic efficiency of antitumor agents, which was further supported by the remarkable enhancement in in vivo antitumor efficacy via promoting apoptosis of tumor cells for paclitaxel (PTX)-loaded CTT-PMs (PTX/CTT-PMs) with low toxicity compared with PTX/TT-PMs. Our findings offered an alternative design strategy for procedurally targeted delivery of chemotherapeutics by an oral route.


Asunto(s)
Antineoplásicos , Micelas , Ratones , Animales , Antineoplásicos/farmacología , Polímeros , Paclitaxel , Poliésteres , Carnitina
16.
ACS Appl Mater Interfaces ; 15(22): 27010-27017, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37233725

RESUMEN

Strain-induced aggregate state instability in organic semiconductor (OSC) films is a critical and bottleneck issue in the practicalization process of organic field-effect transistors (OFETs), but this issue lacks deep insight and effective solutions for a long time. Herein, we developed a novel and general strain balance strategy for stabilizing the aggregate state of OSC films and enhancing the robustness of OFETs. The charge transport zone in OSC films located at the OSC/dielectric interface always suffers from the intrinsic tensile strain induced by substrates and tends to dewet. By introducing a compressive strain layer, the tensile strain can be well balanced and OSC films attain a highly stable aggregate state. Consequently, the OFETs based on strain-balanced OSC heterojunction films exhibit excellent operational and storage stability. This work provides an effective and general strategy to stabilize OSC films and gives guidance in constructing highly stable organic heterojunction devices.

17.
J Phys Chem Lett ; : 5291-5303, 2022 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-35674782

RESUMEN

Converting CO2 into value-added chemicals through hydrogenation can optimize the energy structure dominated by fossil energy, effectively alleviate environmental problems, and achieve full utilization of carbon resources. However, the traditional CO2 hydrogenation reactions need to be carried out under high temperature and pressure, causing inevitable secondary pollution to the environment. A fundamental way to solve these problems is to use clean solar energy to convert CO2 into value-added chemicals and to establish an artificial carbon cycle process. In this Perspective, we highlight recent advances in photodriven CO2 conversion, including the reverse water-gas-shift reaction, methanation reaction, methanol synthesis reaction, and C2+ hydrocarbon synthesis reaction. Finally, we also discuss the challenges and future investigation opportunities for modulating the selective conversion of CO2. This Perspective offers guidance for the design of photodriven CO2 conversion or even the entire C1 catalyst chemistry for tuning product selectivity and activity.

18.
IEEE Trans Cybern ; 52(12): 13572-13585, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34554923

RESUMEN

Existing deep reinforcement learning (DRL)-based methods for solving the capacitated vehicle routing problem (CVRP) intrinsically cope with a homogeneous vehicle fleet, in which the fleet is assumed as repetitions of a single vehicle. Hence, their key to construct a solution solely lies in the selection of the next node (customer) to visit excluding the selection of vehicle. However, vehicles in real-world scenarios are likely to be heterogeneous with different characteristics that affect their capacity (or travel speed), rendering existing DRL methods less effective. In this article, we tackle heterogeneous CVRP (HCVRP), where vehicles are mainly characterized by different capacities. We consider both min-max and min-sum objectives for HCVRP, which aim to minimize the longest or total travel time of the vehicle(s) in the fleet. To solve those problems, we propose a DRL method based on the attention mechanism with a vehicle selection decoder accounting for the heterogeneous fleet constraint and a node selection decoder accounting for the route construction, which learns to construct a solution by automatically selecting both a vehicle and a node for this vehicle at each step. Experimental results based on randomly generated instances show that, with desirable generalization to various problem sizes, our method outperforms the state-of-the-art DRL method and most of the conventional heuristics, and also delivers competitive performance against the state-of-the-art heuristic method, that is, slack induction by string removal. In addition, the results of extended experiments demonstrate that our method is also able to solve CVRPLib instances with satisfactory performance.

19.
J Acad Nutr Diet ; 122(5): 1000-1012, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34781003

RESUMEN

BACKGROUND: Little is known about whether or not diet quality is associated with race/ethnicity as well as hypertension awareness status among adults with hypertension. OBJECTIVE: The aim of this study was to examine associations between diet quality and race/ethnicity as well as hypertension awareness. DESIGN: Analysis of the 2011-2018 National Health and Nutrition Examination Survey, a cross-sectional survey representative of the US population. PARTICIPANTS/SETTING: A total of 6,483 participants with hypertension who were at least 18 years old and had dietary recall data were included. MAIN OUTCOME MEASURES: Diet quality was assessed by Healthy Eating Index 2015 (HEI-2015). STATISTICAL ANALYSIS PERFORMED: Weighted χ2 tests were employed to test associations between categorical variables. Weighted linear regression was used to model the HEI-2015 score by various covariates. RESULTS: Among the 6,483 participants with hypertension included in this study, the average HEI-2015 total score was 54.0 out of the best possible score of 100. In unadjusted analysis, the HEI-2015 total score was significantly different by race/ethnicity (P < 0.01), being 60.9 for non-Hispanic Asian participants, 54.4 for Hispanic, 53.8 for non-Hispanic White, and 52.7 for non-Hispanic Black participants. The HEI-2015 component scores were statistically different by race/ethnicity for all the 13 components (all P values < 0.01). In adjusted analysis, race/ethnicity was significantly associated with the total HEI-2015 score (P < 0.0001), but hypertension awareness status was not (P = 0.99), after controlling for age, sex, body mass index, marital status, education level, income level, and insurance status. CONCLUSIONS: There were significant racial/ethnic differences in HEI-2015 scores among participants with hypertension. Hypertension awareness status was not associated with HEI-2015 scores. Further study is needed to identify reasons why there was an association between HEI-2015 scores and race/ethnicity, and a lack of association with hypertension awareness.


Asunto(s)
Dieta Saludable , Hipertensión , Adolescente , Adulto , Estudios Transversales , Dieta , Etnicidad , Humanos , Hipertensión/epidemiología , Encuestas Nutricionales , Estados Unidos
20.
J Dermatol Sci ; 107(1): 17-23, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35840473

RESUMEN

BACKGROUND: Yohimbine hydrochloride (YH) is a prescription drug to treat erectile dysfunction. It also had potential in fighting high blood pressure and diabetic neuropathy as well as promoting weight loss. OBJECTIVE: The aim of the study is to investigate the anti-melanogenic function of yohimbine hydrochloride and reveal its underlying molecular mechanism. METHODS: B16F10 mouse melanoma cells, Melan-A murine melanocyte, Zebrafish embryos and C57BL/6 mouse ear skins were treated with different concentrations of YH. The extracellular and cellular melanin content was detected by spectrometry. The expression of microphthalmia-associated transcription factor (MITF), tyrosinase and the activities of Wnt/ß-catenin and p38/MAPK signal pathways were determined by RT-qPCR, Western blot analysis and immunofluorescent staining. RESULTS: Melanin production could be effectively inhibited by YH at the safe concentration in vitro and in vivo. Q-PCR and WB results showed that the expression of MITF and tyrosinase were strongly downregulated after YH treatments along with the reduction of tyrosinase activity. YH markedly inhibited ß-catenin nuclear accumulation and p38 phosphorylation in B16F10 cells compared with the untreated controls. Importantly, the increase of MITF expression induced by ß-catenin activator BIO and p38 activator anisomycin could be fully reversed by YH treatments. CONCLUSIONS: These results indicate that YH can function as an anti-melanogenic agent, at least in part, by inhibiting Wnt/ß-catenin and p38/MAPK signal pathways. Therefore, YH may be potentially used as a skin-whitening compound for preventing hyperpigmentation disorders in the future.


Asunto(s)
Melaninas , Melanoma Experimental , Animales , Línea Celular Tumoral , Ratones , Ratones Endogámicos C57BL , Factor de Transcripción Asociado a Microftalmía , Monofenol Monooxigenasa , Transducción de Señal , Yohimbina , Pez Cebra , beta Catenina , Proteínas Quinasas p38 Activadas por Mitógenos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA