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1.
ACS Nano ; 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38776469

RESUMEN

Ligands play a critical role in the optical properties and chemical stability of colloidal nanocrystals (NCs), but identifying ligands that can enhance NC properties is daunting, given the high dimensionality of chemical space. Here, we use machine learning (ML) and robotic screening to accelerate the discovery of ligands that enhance the photoluminescence quantum yield (PLQY) of CsPbBr3 perovskite NCs. We developed a ML model designed to predict the relative PL enhancement of perovskite NCs when coordinated with a ligand selected from a pool of 29,904 candidate molecules. Ligand candidates were selected using an active learning (AL) approach that accounted for uncertainty quantified by twin regressors. After eight experimental iterations of batch AL (corresponding to 21 initial and 72 model-recommended ligands), the uncertainty of the model decreased, demonstrating an increased confidence in the model predictions. Feature importance and counterfactual analyses of model predictions illustrate the potential use of ligand field strength in designing PL-enhancing ligands. Our versatile AL framework can be readily adapted to screen the effect of ligands on a wide range of colloidal nanomaterials.

2.
Sensors (Basel) ; 24(9)2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38733019

RESUMEN

The burgeoning interest in intelligent transportation systems (ITS) and the widespread adoption of in-vehicle amenities like infotainment have spurred a heightened fascination with vehicular ad-hoc networks (VANETs). Multi-hop routing protocols are pivotal in actualizing these in-vehicle services, such as infotainment, wirelessly. This study presents a novel protocol called multiple junction-based traffic-aware routing (MJTAR) for VANET vehicles operating in urban environments. MJTAR represents an advancement over the improved greedy traffic-aware routing (GyTAR) protocol. MJTAR introduces a distributed mechanism capable of recognizing vehicle traffic and computing curve metric distances based on two-hop junctions. Additionally, it employs a technique to dynamically select the most optimal multiple junctions between source and destination using the ant colony optimization (ACO) algorithm. We implemented the proposed protocol using the network simulator 3 (NS-3) and simulation of urban mobility (SUMO) simulators and conducted performance evaluations by comparing it with GSR and GyTAR. Our evaluation demonstrates that the proposed protocol surpasses GSR and GyTAR by over 20% in terms of packet delivery ratio, with the end-to-end delay reduced to less than 1.3 s on average.

3.
Adv Mater ; : e2403820, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38720475

RESUMEN

Graphene's wetting transparency offers promising avenues for creating multifunctional devices by allowing real-time wettability control on liquid substrates via the flow of different liquids beneath graphene. Despite its potential, direct measurement of floating graphene's wettability remains a challenge, hindering the exploration of these applications. The current study develops an experimental methodology to assess the wetting transparency of single-layer graphene (SLG) on liquid substrates. By employing contact angle measurements and Neumann's Triangle model, the challenge of evaluating the wettability of floating free-suspended single-layer graphene is addressed. The research reveals that for successful contact angle measurements, the testing and substrate liquids must be immiscible. Using diiodomethane as the testing liquid and ammonium persulfate solution as liquid substrate, the study demonstrates the near-complete wetting transparency of graphene. Furthermore, it successfully showcases the feasibility of real-time wettability control using graphene on liquid substrates. This work not only advances the understanding of graphene's interaction with liquid interfaces but also suggests a new avenue for the development of multifunctional materials and devices by exploiting the unique wetting transparency of graphene.

4.
Food Sci Biotechnol ; 33(3): 599-606, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38274177

RESUMEN

Understanding human oral/taste sensitivity to long-chain non-esterified fatty acids (NEFA) with varying physicochemical properties is essential to reducing the intake of fats and altering the intake composition. This study investigated the differences in human taste sensitivity to two NEFA: oleic acid and linoleic acid. Twenty-four female subjects were divided into two equal sensitivity groups, and they performed discrimination tests for both fatty acids against bottled water using either the triangle or the DR A-Not A test. To achieve an accurate measurement of NEFA sensitivity, the stimulus was carefully prepared, avoiding additives that could interfere with the binding of fatty acids to receptors. Stimuli concentrations were selected to be within the lowest range (9.9 to 177.3 µM) evaluated in previous research. Through a systematic stimulus control process, this study confirmed that greater sensitivity was exhibited to linoleic acid than oleic acid, resulting in better discrimination than previous studies.

5.
Biol Reprod ; 110(2): 300-309, 2024 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-37930227

RESUMEN

The intervillous space of human placenta is filled with maternal blood, and villous trophoblasts are constantly exposed to the shear stress generated by maternal blood pressure and flow throughout the entire gestation period. However, the effects of shear stress on villous trophoblasts and their biological significance remain unknown. Here, using our recently established naïve human pluripotent stem cells-derived cytotrophoblast stem cells (nCTs) and a device that can apply arbitrary shear stress to cells, we investigated the impact of shear stress on early-stage trophoblasts. After 72 h of exposure to 10 dyn/cm2 shear stress, nCTs became fused and multinuclear, and mRNA expression of the syncytiotrophoblast (ST) markers, such as glial cell missing 1, endogenous retrovirus group W member 1 envelope, chorionic gonadotropin subunit beta 3, syndecan 1, pregnancy specific beta-1-glycoprotein 3, placental growth factor, and solute carrier family 2 member 1 were significantly upregulated compared to static conditions. Immunohistochemistry showed that shear stress increased fusion index, human chorionic gonadotropin secretion, and human placental lactogen secretion. Increased microvilli formation on the surface of nCTs under flow conditions was detected using scanning electron microscopy. Intracellular cyclic adenosine monophosphate significantly increased under flow conditions. Moreover, transcriptome analysis of nCTs subjected to shear stress revealed that shear stress upregulated ST-specific genes and downregulated CT-specific genes. Collectively, these findings indicate that shear stress promotes the differentiation of nCTs into ST.


Asunto(s)
Células Madre Pluripotentes Inducidas , Placenta , Femenino , Embarazo , Humanos , Placenta/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Factor de Crecimiento Placentario/metabolismo , Trofoblastos/metabolismo , Gonadotropina Coriónica/farmacología , Gonadotropina Coriónica/metabolismo , Diferenciación Celular
7.
Food Res Int ; 173(Pt 2): 113441, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37803767

RESUMEN

Preserving the sensory characteristics of reformulated products is crucial for a successful market launch. This underscores the need for precise measurement of consumer perceptions regarding sensory differences and preferences. One approach to assess these aspects is through the utilization of the reminder-preference test, an affective difference-preference test employing the A-Not A with the reminder (A-Not AR) test design. This test measures sensory differences and preferences by employing a consolidated d' index rooted in signal detection theory and Thurstonian modeling. The aim of this study was to assess the efficacy of the reminder-preference test in measuring the degree of sensory differences and interpreting their relevance concerning consumer preference. To achieve this, the test was compared with both the A-Not AR difference test and the 2-alternative choice (2-AC) preference test. A lemon-lime-flavored carbonated drink and two types of reformulated samples were tested. Young female adult subjects were randomly divided into three groups. Each took one of the following three tests: the reminder-preference test, the reminder test of A-Not AR, or the 2-AC preference test. The reference framing in the reminder-preference and reminder tests was preceded by subjects watching the product's advertisement to assist them in framing evaluative criteria. This would also facilitate memorizing the perception of the reference product. Test sensitivity in reminder-preference matched reminder and 2-AC tests for sensory differences and preferences. Affective framing enhanced sensitivity to sensory differences resulting in a higher d' value of the sensory difference than the preference. From the results, it was possible to interpret that the measured sensory differences did not affect consumer preference. The test also illuminated brand marketing effects on preferences through branded reference comparison. Thus, the reminder-preference test shows potential as an efficient sensory method to measure sensory differences and the preference of consumers, while concurrently measuring the effects of marketing on the consumers. Therefore, it can assist in making efficient business decisions regarding product reformulations.


Asunto(s)
Toma de Decisiones , Gusto , Adulto , Humanos , Femenino , Comportamiento del Consumidor , Bebidas Gaseosas , Comercio
8.
Medicina (Kaunas) ; 59(8)2023 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-37629711

RESUMEN

Background: Extracorporeal membrane oxygenation (ECMO) is an accommodation of the cardiopulmonary bypass technique that can support gas exchange and hemodynamic stability. It is used as a salvage maneuver in patients with life-threatening respiratory or cardiac failure that does not respond to conventional treatment. There are few case reports of successful perioperative use of ECMO, especially preoperatively, in liver transplantation (LT). Here, we report an experience of successful anesthetic management in deceased donor liver transplantation (DDLT) by applying perioperative veno-venous (VV) ECMO support in the setting of acute respiratory distress syndrome (ARDS) aggravated by hepatopulmonary syndrome (HPS). Case: A 25-year-old female (156.0 cm, 65.0 kg), without any underlying disease, was referred to our emergency department for decreased mentality. Based on imaging and laboratory tests, she was diagnosed with acute liver failure of unknown cause combined with severe ARDS aggravated by HPS. Since the patient faced life-threatening hypoxemia with a failure of conventional ventilation maneuvers, preoperative VV ECMO was initiated and maintained during the operation. The patient remained hemodynamically stable throughout DDLT, and ARDS showed gradual improvement after the administration of VV ECMO. As ARDS improved, the patient's condition alleviated, and VV ECMO was weaned on postoperative day 6. Conclusions: This case demonstrates that VV ECMO may be a useful therapeutic option not only during the intraoperative and postoperative periods but also in the preoperative period for patients with liver failure combined with reversible respiratory failure.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Síndrome Hepatopulmonar , Trasplante de Hígado , Síndrome de Dificultad Respiratoria , Femenino , Humanos , Adulto , Síndrome Hepatopulmonar/complicaciones , Síndrome Hepatopulmonar/cirugía , Donadores Vivos , Síndrome de Dificultad Respiratoria/complicaciones , Síndrome de Dificultad Respiratoria/terapia
9.
Sensors (Basel) ; 23(14)2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37514631

RESUMEN

Reconfigurable intelligent surface (RIS) has emerged as a promising technology to enhance the spectral efficiency of wireless communication systems. However, if there are many obstacles between the RIS and users, a single RIS may not provide sufficient performance. For this reason, a double RIS-aided communication system is proposed in this paper. However, this system also has a problem: the signal is attenuated three times due to the three channels created by the double RIS. To overcome these attenuations, an active RIS is proposed in this paper. An active RIS is almost the same as a conventional RIS, except for the included amplifier. Comprehensively, the proposed system overcomes various obstacles and attenuations. In this paper, an active RIS is applied to the second RIS. To reduce the power consumption of active elements, a partially active RIS is applied. To optimize the RIS elements, the sum of the covariance matrix is found by using channels related to each RIS, and the right singular vector is exploited using singular value decomposition for the sum of the covariance matrix. Then, the singular value of the sum of the covariance value is checked to determine which element is the active element. Simulation results show that the proposed system has better sum rate performance compared to a single RIS system. Although it has a lower sum rate performance compared to a double RIS with fully active elements, the proposed system will be more attractive in the future because it has much better energy efficiency.

11.
Anesth Pain Med (Seoul) ; 18(3): 252-259, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37468208

RESUMEN

BACKGROUND: Remimazolam is a novel benzodiazepine with fast onset and short half-life. We compared the effects of remimazolam and propofol on recovery profiles for general anesthesia in patients undergoing laparoscopic cholecystectomy. METHODS: We randomly assigned 108 patients to either a remimazolam (n=54) or propofol (n=54) group. Remimazolam and propofol were used for induction and maintanance of anesthesia. Following anesthesia, we recorded the time until an Aldrete score of 9 was achieved as the primary surrogate marker of complete recovery. The time to reach a Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score of 2 and the time from the end of anesthesia to eye opening time, recovery time of orientation, time to spontaneous breathing, extubation time, and the time required for analgesics were measured. Heart rate, blood pressure, and bispectral index were assessed before, during, and after pneumoperitoneum. RESULTS: We included 101 patients in the analysis. In the remimazolam group, it took longer to reach an Aldrete score of 9 after the drug infusion ended (P = 0.031). There was no difference in the time to reach MOAA/S 2 between the two groups. The time to eye opening, recovery time of orientation, and time required for analgesics were longer and heart rate was higher in the remimazolam group. Neither blood pressure, nor extubation time differed between groups. CONCLUSIONS: Remimazolam and propofol provided safe induction and maintenance of anesthesia in patients undergoing laparoscopic cholecystectomy. The recovery time from anesthesia was longer than that with propofol. Fewer hemodynamic changes were observed with remimazolam, but further studies are needed.

12.
Obstet Gynecol Sci ; 66(4): 270-289, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37194243

RESUMEN

The coronavirus disease 2019 (COVID-19) outbreak which started in December 2019 rapidly developed into a global health concern. Pregnant women are susceptible to respiratory infections and can experience adverse outcomes. This systematic review and meta-analysis compared pregnancy outcomes according to COVID-19 disease status. The MEDLINE, EMBASE, and Cochrane Library databases were searched for relevant articles published between December 1, 2019, and October 19, 2022. Main inclusion criterion was any population-based, cross-sectional, cohort, or case-control study that assessed pregnancy outcomes in women with or without laboratory-confirmed COVID-19. Sixty-nine studies including 1,606,543 pregnant women (39,716 [2.4%] diagnosed with COVID-19) were retrieved. COVID-19-infected pregnant women had a higher risk of preterm birth (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.42-1.78), preeclampsia (OR, 1.41; 95% CI, 1.30-1.53), low birth weight (OR, 1.52; 95% CI, 1.30-1.79), cesarean delivery (OR, 1.20; 95% CI, 1.10-1.30), stillbirth (OR, 1.71; 95% CI, 1.39-2.10), fetal distress (OR, 2.49; 95% CI, 1.54-4.03), neonatal intensive care unit admission (OR, 2.33; 95% CI, 1.72-3.16), perinatal mortality (OR, 1.96; 95% CI, 1.15-3.34), and maternal mortality (OR, 6.15; 95% CI, 3.74-10.10). There were no significant differences in total miscarriage, preterm premature rupture of membranes, postpartum hemorrhage, cholestasis, or chorioamnionitis according to infection. This review demonstrates that COVID-19 infection during pregnancy can lead to adverse pregnancy outcomes. This information could aid researchers and clinicians in preparing for another pandemic caused by newly discovered respiratory viruses. The findings of this study may assist with evidence-based counseling and help clinicians manage pregnant women with COVID-19.

13.
Sensors (Basel) ; 23(8)2023 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-37112273

RESUMEN

The reconfigurable intelligent surface (RIS) and rate-splitting multiple access (RSMA) are considered as promising technologies for the beyond Fifth-Generation (B5G) and Sixth-Generation (6G) wireless systems by controlling the propagation environment, which attenuates the transmitted signal, and by managing the interference by splitting the user message into common and private messages. Because conventional RIS elements have each impedance connected to the ground, the sum-rate performance improvement of the RIS is limited. Therefore, the new RISs, which have impedance elements connected to each other, have been proposed recently. To be more adaptive to each channel, the optimization of the grouping of the RIS elements is required. Furthermore, since the solution of the optimal rate-splitting (RS) power-splitting ratio is complex, the value should be simply optimized to be more practical in the wireless system. In this paper, the grouping scheme of the RIS elements according to the user scheduling and the solution of the RS power-splitting ratio based on fractional programming (FP) are proposed. The simulation results showed that the proposed RIS-assisted RSMA system achieved a high sum-rate performance compared to the conventional RIS-assisted spatial-division multiple access (SDMA) system. Therefore, the proposed scheme can perform adaptively for the channel and has a flexible interference management. Furthermore, it can be a more suitable technique for B5G and 6G.

14.
Food Res Int ; 167: 112592, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37087202

RESUMEN

Signal detection theory (SDT) sensory discrimination analysis using A-Not A with a two-step rating is an efficient approach to in-house sensory quality management in the food industry. For such sensory analysis using an internal panel, the panels' ability to use stable decision criteria and provide a consistent response distribution responding to "A" vs "Not A" is critical for guaranteeing the data quality. This study examined the effects of the familiarization procedure (FP) and reference presentation probability (RPP) in the SDT A-Not A rating protocol on the panels' sensory learning of samples and stability of decision criteria using SDT parameters, recognition d' (d'Rec),criteria location (c), and discrimination d' indices. Three different protocols were compared using ice-tea samples with small differences: Control, 0.25 RPP with repeated reference tasting (FPR); Modified-1, 0.25 RPP with reference categorization (FPC); Modified-2, 0.5 RPP with reference categorization (FPC). An independent sample design with three groups having equal sensitivity was used to identify the differences among the protocols. For each protocol, two sub-groups with similar decision criteria (response bias) were formed according to the results obtained from the pre-test and used for the main-test analysis. SDT analysis results indicated that the Modified-2 protocol with a higher RPP (0.5) induced the most efficient sensory learning of the reference. The protocol improved the subjects' recognition of the reference and test samples, better differentiating from the reference and stabilizing the decision criterion, resulting in higher discrimination performance (larger d'). The results showed that d'Rec analysis, together with d' analysis using a sensory panel, is a useful tool for monitoring the panel performance and checking for the sensory data quality of the sensory difference tests. In the present paper, a detailed illustration of the A-Not A sensory test procedure and examples of how to apply the SDT indices for different business decision-making is also introduced using the design and results of the present experiment.


Asunto(s)
Análisis de los Alimentos , Sensación , Humanos , Análisis de los Alimentos/métodos
15.
J Community Health Nurs ; 40(3): 157-166, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37058006

RESUMEN

The study aims to determine the effect of virtual simulation practice in nursing students using the Virtual Patient Learning System Evaluation (VPLSE) tool. The study uses descriptive research, centering on correlation and regression analysis. 295 nursing students in Grades 3 and 4 who have experienced virtual simulation practice within the past year were included. The main variables of VPLSE comprise four sub-domains: nursing knowledge improvement, clinical competency development, confidence in nursing performance, and nursing care plan application. In addition to the VPLSE, two other tools, measuring virtual presence and self-efficacy, were utilized. The VPLSE was significantly positively correlated with virtual presence and self-efficacy, respectively. The VPLSE subdomain of "clinical competency development" had a strong positive correlation with virtual presence. To increase the effect of virtual simulation education, it is necessary to maintain the advantages of virtual simulation practice, such as freedom from space and time, repeated learning, psychological stability and application of nursing plans.


Asunto(s)
Bachillerato en Enfermería , Entrenamiento Simulado , Estudiantes de Enfermería , Humanos , Autoeficacia , Estudiantes de Enfermería/psicología , Aprendizaje , Competencia Clínica
16.
Sci Rep ; 13(1): 4140, 2023 03 13.
Artículo en Inglés | MEDLINE | ID: mdl-36914667

RESUMEN

Spinach has been suggested as a potential rotation crop for increasing crop yield by enhancing beneficial fungal microbes in continuous monocropping. However, no research on the use of spinach as a green manure has been reported. Thus, we tested the effects of spinach and Korean mustard cultivars (green and red mustards) (10 g pot -1) as green manure on soil chemical properties, pepper productivity, and soil microbiome of long-year pepper-monocropped soil. Spinach improved the soil nutrition (e.g., pH, SOM, TN, NH4+, and K), weed suppression, and pepper growth. Spinach had by far the highest fruit yield, over 100% pepper fruit yield increment over the mustard green manures and control. Our study showed that the major influencing factors to cause a shift in both bacterial and fungal community assemblies were soil pH, TC TN, and K. Following green manure amendment Bacillota, especially Clostridium, Bacillus and Sedimentibacter, were enriched, whereas Chloroflexi and Acidobacteriota were reduced. In addition, spinach highly reduced the abundance of Leotiomycetes and Fusarium but enriched Papiliotrema. FAPROTAX and FUNGuild analysis revealed that predicted functional profiles of bacterial and fungal communities in spinach-amended soil were changed. Spinach-treated soil was differentially abundant in function related to hydrocarbon degradation and functional guilds of symbiotrophs and ectomycorrhizal. This study contributes significantly to our understanding of how the soil fertility and soil microbiome alteration via spinach green manure application as a pre-plant soil treatment might help alleviate continuous cropping obstacles.


Asunto(s)
Microbiota , Suelo , Suelo/química , Spinacia oleracea , Estiércol , Nutrientes , Bacterias , Microbiología del Suelo
17.
Proc Natl Acad Sci U S A ; 120(1): e2213099120, 2023 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-36577057

RESUMEN

The cochlea's ability to discriminate sound frequencies is facilitated by a special topography along its longitudinal axis known as tonotopy. Auditory hair cells located at the base of the cochlea respond to high-frequency sounds, whereas hair cells at the apex respond to lower frequencies. Gradual changes in morphological and physiological features along the length of the cochlea determine each region's frequency selectivity, but it remains unclear how tonotopy is established during cochlear development. Recently, sonic hedgehog (SHH) was proposed to initiate the establishment of tonotopy by conferring regional identity to the primordial cochlea. Here, using mouse genetics, we provide in vivo evidence that regional identity in the embryonic cochlea acts as a framework upon which tonotopy-specific properties essential for frequency selectivity in the mature cochlea develop. We found that follistatin (FST) is required for the maintenance of apical cochlear identity, but dispensable for its initial induction. In a fate-mapping analysis, we found that FST promotes expansion of apical cochlear cells, contributing to the formation of the apical cochlear domain. SHH, in contrast, is required both for the induction and maintenance of apical identity. In the absence of FST or SHH, mice produce a short cochlea lacking its apical domain. This results in the loss of apex-specific anatomical and molecular properties and low-frequency-specific hearing loss.


Asunto(s)
Folistatina , Proteínas Hedgehog , Animales , Ratones , Folistatina/genética , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Cóclea/fisiología , Audición/fisiología , Mamíferos/metabolismo
18.
Sensors (Basel) ; 22(18)2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-36146342

RESUMEN

Non-orthogonal multiple access (NOMA) has great potential to implement the fifth-generation (5G) requirements of wireless communication. For a NOMA traditional detection method, successive interference cancellation (SIC) plays a vital role at the receiver side for both uplink and downlink transmission. Due to the complex multipath channel environment and prorogation of error problems, the traditional SIC method has a limited performance. To overcome the limitation of traditional detection methods, the deep-learning method has an advantage for the highly efficient tool. In this paper, a deep neural network which has bi-directional long short-term memory (Bi-LSTM) for multiuser uplink channel estimation (CE) and signal detection of the originally transmitted signal is proposed. Unlike the traditional CE schemes, the proposed Bi-LSTM model can directly recover multiuser transmission signals suffering from channel distortion. In the offline training stage, the Bi-LTSM model is trained using simulation data based on channel statistics. Then, the trained model is used to recover the transmitted symbols in the online deployment stage. In the simulation results, the performance of the proposed model is compared with the convolutional neural network model and traditional CE schemes such as MMSE and LS. It is shown that the proposed method provides feasible improvements in performance in terms of symbol-error rate and signal-to-noise ratio, making it suitable for 5G wireless communication and beyond.


Asunto(s)
Redes de Comunicación de Computadores , Noma , Algoritmos , Humanos , Redes Neurales de la Computación , Relación Señal-Ruido
19.
Phys Chem Chem Phys ; 24(34): 20082-20093, 2022 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-35975684

RESUMEN

The Diels-Alder (DA) reaction, a classic cycloaddition reaction involving a diene and a dienophile to form a cyclohexene, is among the most versatile organic reactions. Theories have predicted thermodynamically unfavorable DA reactions on pristine graphene owing to its low chemical reactivity. We hypothesized that metals like Ni could enhance the reactivity of graphene towards DA reactions through charge transfer. The results indeed showed that metal substrates enhanced the reactivity of graphene in the DA reactions with a diene, 2,3-dimethoxy butadiene (DMBD), and a dienophile, maleic anhydride (MAH), with the activity enhancement in the order of Ni > Cu, and both are more reactive than graphene supported on silicon wafer. The rate constants were estimated to be two times higher for graphene supported on Ni than on silicon wafer. The computational results support the experimentally obtained rate trend of Ni > Cu, both predicted to be greater than unsupported graphene, which is explained by the enhanced graphene-substrate interaction reflected in charge transfer effects with the strongly interacting Ni. This study opens up a new avenue for enhancing the chemical reactivity of pristine graphene through substrate selection.

20.
Clocks Sleep ; 4(2): 277-286, 2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35735604

RESUMEN

Many plants have been used in Korean medicine for treating insomnia. However, scientific evidence for their sedative activity has not been fully investigated. Thus, this study was carried out to investigate the sedative effects of the extracts of medicinal plants, including Yukmijihwang-tang and its various modified forms through the 5-HT2c receptor binding assay, and to further confirm its sleep-promoting effects and the underlying neural mechanism in rats utilizing electroencephalography (EEG) analysis. Enzyme-linked immunosorbent assay (ELISA) was used to measure serotonin (5-HT) in the brain. The water extracts of modified Yukmijihwang-tang (YmP) displayed binding affinity to the 5-HT2C receptor (IC50 value of 199.9 µg/mL). YmP (50 mg/kg) administration decreased wake time and increased REM and NREM sleep based on EEG data in rats. Additionally, treatment with YmP significantly increased the 5-HT level in the hypothalamus. In conclusion, the sedative effect of YmP can be attributed to the activation of the central serotonergic systems, as evidenced by the high affinity of binding of the 5-HT2C receptor and increased 5-HT levels in the brain of the rat. This study suggests that YmP can be a new material as a sleep inducer in natural products.

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