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The identification of viruses from negative staining transmission electron microscopy (TEM) images has mainly depended on experienced experts. Recent advances in artificial intelligence have enabled virus recognition using deep learning techniques. However, most of the existing methods only perform virus classification or semantic segmentation, and few studies have addressed the challenge of virus instance segmentation in TEM images. In this paper, we focus on the instance segmentation of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and other respiratory viruses and provide experts with more effective information about viruses. We propose an effective virus instance segmentation network based on the You Only Look At CoefficienTs backbone, which integrates the Swin Transformer, dense connections and the coordinate-spatial attention mechanism, to identify SARS-CoV-2, H1N1 influenza virus, respiratory syncytial virus, Herpes simplex virus-1, Human adenovirus type 5 and Vaccinia virus. We also provide a public TEM virus dataset and conduct extensive comparative experiments. Our method achieves a mean average precision score of 83.8 and F1 score of 0.920, outperforming other state-of-the-art instance segmentation algorithms. The proposed automated method provides virologists with an effective approach for recognizing and identifying SARS-CoV-2 and assisting in the diagnosis of viruses. Our dataset and code are accessible at https://github.com/xiaochiHNU/Virus-Instance-Segmentation-Transformer-Network.
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Subtipo H1N1 del Virus de la Influenza A , Virus de la Influenza A , Humanos , Inteligencia Artificial , Algoritmos , SARS-CoV-2RESUMEN
Parkinson's disease (PD) is one of the most common neurodegenerative disorders and is characterized by loss of dopaminergic neurons in the substantia nigra (SN), causing bradykinesia and rest tremors. Although the molecular mechanism of PD is still not fully understood, neuroinflammation has a key role in the damage of dopaminergic neurons. Herein, we found that kurarinone, a unique natural product from Sophora flavescens, alleviated the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced behavioral deficits and dopaminergic neurotoxicity, including the losses of neurotransmitters and tyrosine hydroxylase (TH)-positive cells (SN and striatum [STR]). Furthermore, kurarinone attenuated the MPTP-mediated neuroinflammation via suppressing the activation of microglia involved in the nuclear factor kappa B signaling pathway. The proteomics result of the solvent-induced protein precipitation and thermal proteome profiling suggest that the soluble epoxide hydrolase (sEH) enzyme, which is associated with the neuroinflammation of PD, is a promising target of kurarinone. This is supported by the increase of plasma epoxyeicosatrienoic acids (sEH substrates) and the decrease of dihydroxyeicosatrienoic acids (sEH products), and the results of in vitro inhibition kinetics, surface plasmon resonance, and cocrystallization of kurarinone with sEH revealed that this natural compound is an uncompetitive inhibitor. In addition, sEH knockout (KO) attenuated the progression of PD, and sEH KO plus kurarinone did not further reduce the protection of PD in MPTP-induced PD mice. These findings suggest that kurarinone could be a potential natural candidate for the treatment of PD, possibly through sEH inhibition.
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Epóxido Hidrolasas/metabolismo , Flavonoides/uso terapéutico , Enfermedad de Parkinson/prevención & control , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/farmacología , Animales , Modelos Animales de Enfermedad , Epóxido Hidrolasas/genética , Eliminación de Gen , Ratones , Microglía/efectos de los fármacos , Especificidad por SustratoRESUMEN
Multicolor afterglow patterns with transparent and traceless features are important for the exploration of new functionalities and applications. Herein, we report a direct in situ patterning technique for fabricating afterglow carbon dots (CDs) based on laser direct writing (LDW) for the first time. We explore a facile step-scanning method that reduces the heat-affected zone and avoids uneven heating, thus producing a fine-resolution afterglow CD pattern with a minimum line width of 80 µm. Unlike previous LDW-induced luminescence patterns, the patterned CD films are traceless and transparent, which is mainly attributed to a uniform heat distribution and gentle temperature rise process. Interestingly, by regulating the laser parameters and CD precursors, an increased carbonization and oxidation degree of CDs could be obtained, thus enabling time-dependent, tunable afterglow colors from blue to red. In addition, we demonstrate their potential applications in the in situ fabrication of flexible and stretchable optoelectronics.
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INTRODUCTION: This study examined the long-term effectiveness of cognitive behavioral therapy (CBT) (≥ 2 years after the end of therapy) in the routine care of youth (mean 11.95 years; SD = 3.04 years) with primary anxiety disorder (AD). METHODS: Two hundred and ten children with any AD as a primary diagnosis and with any comorbidity were included in the "Kids Beating Anxiety (KibA)" clinical trial and received evidence-based CBT. Diagnoses, severity of diagnoses, and further dimensional outcome variables of symptoms and functioning were assessed before (baseline), after the last treatment session (POST), and at two follow-up (FU) assessments in the child and caregiver report: 6 months (6MONTHS-FU) and >2 years (mean 4.31; SD = 1.07 years) after the last treatment session (long-term FU). RESULTS: At POST, 61.38% showed total remission of all and any ADs. At long-term FU, the remission rate was 63.64%. Compared to baseline, ratings of severity, anxiety, impairment/burden, and life quality improved significantly after CBT in child and caregiver report. All pre-post/FU improvements and global success ratings were stable in child (Pre-Post: Hedges' g = 3.57; Pre-6MONTHS-FU: Hedges' g = 3.43; Pre-LT-FU: Hedges' g = 2.34) and caregiver report (Pre-Post: Hedges' g = 2.00; Pre-6MONTHS-FU: Hedges' g = 2.31; Pre-LT-FU: Hedges' g = 2.31) across all POST- and FU-assessment points. Some outcomes showed further significant improvement, and no deterioration was found over the course of time. Effect sizes calculated in the present study correspond to, or even exceed, effect sizes reported in previous meta-analysis. CONCLUSIONS: Stable long-term effects of "KibA" CBT for youth with ADs, comparable to those results from efficacy studies, were achieved in a routine practice setting by applying treatment manuals tested in randomized controlled trials. These findings are remarkable, as the patient group studied here consisted of an age group within the main risk phase of developing further mental disorders, and therefore an increase in new-onset anxiety and further mental disorders would be expected over the long time span studied here.
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Atención Ambulatoria , Trastornos de Ansiedad , Terapia Cognitivo-Conductual , Humanos , Terapia Cognitivo-Conductual/métodos , Trastornos de Ansiedad/terapia , Femenino , Masculino , Niño , Adolescente , Atención Ambulatoria/métodos , Resultado del Tratamiento , Calidad de VidaRESUMEN
The development of cost-efficient biochar adsorbent with a simple preparation method is essential to constructing efficient wastewater treatment system. Here, a low-cost waste carton biochar (WCB) prepared by a simple two-step carbonization was applied in efficiently removing Rhodamine B (RhB) in aqueous environment. The maximum ability of WCB for RhB adsorption was 222 mg/g, 6 and 10 times higher than both of rice straw biochar (RSB) and broadbean shell biochar (BSB), respectively. It was mainly ascribed to the mesopore structure (3.0-20.4 nm) of WCB possessing more spatial sites compared to RSB (2.2 nm) and BSB (2.4 nm) for RhB (1.4 nmâ1.1 nmâ0.6 nm) adsorption. Furthermore, external mass transfer (EMT) controlled mass transfer resistance (MTR) of the RhB sorption process by WCB which was fitted with the Langmuir model well. Meanwhile, the adsorption process was dominated by physisorption through van der Waals forces and π-π interactions. A mixture of three dyes in river water was well removed by using WCB. This work provides a straightforward method of preparing mesoporous biochar derived from waste carton with high-adsorption capacity for dye wastewater treatment.
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Carbón Orgánico , Aguas Residuales , Contaminantes Químicos del Agua , Colorantes/química , Eliminación de Residuos Líquidos/métodos , Adsorción , Contaminantes Químicos del Agua/análisis , CinéticaRESUMEN
INTRODUCTION: Adherence to COVID-19 mitigation measures is an important vehicle that has contributed to the fight against the pandemic. The present study investigated potential changes of the level of adherence and its predictors between 2020 and 2021 in eight countries. METHODS: Adherence to COVID-19 measures and its potential predictors (perception of usefulness of the measures, rating of the governmental COVID-19 communication, mental health variables, COVID-19 burden) were compared between representative population samples from European Union countries (France, Germany, Poland, Spain, Sweden) and non-European Union countries (Russia, UK, USA) assessed in 2020 (N = 7,658) and 2021 (N = 8,244). RESULTS: In the overall sample, multiple analyses of variance revealed significantly higher levels of adherence to the measures, their perception as useful, positive mental health, and feelings of being well supported and well informed by governments in 2020 than in 2021. In contrast, feelings of being left alone and symptoms of depression, anxiety, and stress were significantly higher in 2021 than in 2020. In France, Poland, Spain, and the UK, the adherence level was significantly higher in 2020 than in 2021. In European Union countries, ratings of governmental communication were less positive, and levels of mental health were lower in 2021 than in 2020. In non-European countries, an opposite result pattern was found. CONCLUSION: The current results indicate a decrease in adherence to the mitigation measures and factors that could foster it. Potential ways how governments and authorities could enhance the population's trust in COVID-19 mitigation measures are discussed.
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COVID-19 , Humanos , COVID-19/prevención & control , Unión Europea , Francia , Alemania , Suecia/epidemiologíaRESUMEN
The regulation of bacterial quorum sensing (QS) has been used to inhibit biofouling in wastewater treatment plants and the formation of biofilms. In contrast to traditional QS regulation strategies, this study aimed to obstruct the transmembrane transport process of QS signals to decrease their extracellular accumulation. Three phytochemicals, astragaloside IV, eugenol, and baicalin were selected, their effects on biofilm formation by Pseudomonas aeruginosa PA14 were studied, and the mechanisms determined. The inhibition efficiency of biofilm formation by 50 mg/L astragaloside IV, 1 mg/L eugenol, and 1 mg/L baicalin were 37%, 26%, and 26%, respectively. Confocal laser scanning microscopy and analysis of extracellular polymeric substances indicated that the three inhibitors affected the structure and composition of the biofilms. Furthermore, bacterial motility and a variety of QS-related virulence factors were suppressed by the inhibitor treatment due to changes in bacterial QS. Notably, the three inhibitors all decreased the extracellular concentration of the QS signaling molecule 3-oxo-C12-homoseine lactone by affecting the function of efflux pump MexAB-OprM. This indirectly interfered with the bacterial QS system and thus inhibited biofilm formation. In conclusion, this study revealed the inhibitory effects and inhibition mechanism of three phytochemicals on efflux pump and QS of P. aeruginosa and realized the inhibition on biofilm formation. We update the efflux pump inhibitor library and provide a new way for biofilm contamination control.
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Percepción de Quorum , Saponinas , Eugenol/farmacología , Biopelículas , Saponinas/farmacología , Antibacterianos/farmacología , Proteínas BacterianasRESUMEN
BACKGROUND: Positive psychology interventions are known to have an impact on mental health as well as on a number of beneficial characteristics like optimism, gratitude and self-efficacy. The Positive Emotions Training (PoET) is one of the first holistic training programs covering eleven positive psychology constructs. The goal of this study was to test PoET's feasibility in the general population and to assess possible effects on positive and negative mental health factors. Additionally, possible effects on optimism, gratitude, happiness, resilience, and self-efficacy were examined. METHODS: The sample (n = 101) was not randomized. Participants were allocated to PoET (n = 55) or control group (n = 46) that did not receive treatment initially. The PoET group completed two training sessions (3.5 h each) that were conducted in an online format with groups of about 30 people. All participants completed positive and negative mental health measures at the beginning of the first training session and at the beginning of the second one as well as 30 days after the second session. Two-factorial repeated measures ANOVAs were conducted to test for possible effects of PoET on mental health. RESULTS: The results showed that the contents were comprehensible and that the conduction of the training was feasible overall. In addition, a significant decrease of depression and anxiety symptoms as well as a significant increase of optimism were found in the PoET group. No significant changes were found in the control group. CONCLUSIONS: Results indicate that PoET is an applicable intervention for improving mental health in the general population. TRIAL REGISTRATION: Retrospectively registered at ClinicalTrials.gov on 21/02/2023 (Identifier/Trial registration number: NCT05737251).
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Intervención basada en la Internet , Salud Mental , Humanos , Ansiedad/terapia , Estudios de Factibilidad , FelicidadRESUMEN
BACKGROUND: Artifactual hypoglycemia is a low glucose measurement in a normoglycemic patient. Patients in a shock state or with extremity hypoperfusion can metabolize a higher proportion of the glucose in the poorly perfused tissue, and blood obtained from those tissues may have far lower glucose concentration than the blood in the central circulation. CASE REPORT: We present the case of a 70-year-old woman with systemic sclerosis, progressive functional decline, and cool digital extremities. The initial point-of-care testing (POCT) for glucose was 55 mg/dL from her index finger, with subsequent repeated low POCT glucose reading, despite glycemic repletion and contradictory euglycemic serologic readings from her peripheral i.v. sites. Two separate POCTs were then obtained from her finger and her antecubital fossa, which had vastly different glucose readings; the latter was in congruence with her i.v. draws. The patient was diagnosed with artifactual hypoglycemia. Alternative sources of blood to avoid artifactual hypoglycemia on POCT samples are discussed. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Artifactual hypoglycemia is a rare but commonly misdiagnosed phenomenon that can occur in emergency department patients when peripheral perfusion is limited. We encourage physicians to confirm peripheral capillary results with a venous POCT or explore alternative sources of blood to avoid artificial hypoglycemia. Small absolute errors can matter when the erroneous result is hypoglycemia.
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Glucemia , Hipoglucemia , Femenino , Humanos , Anciano , Hipoglucemia/diagnóstico , GlucosaRESUMEN
BACKGROUND: Proximal tibiofibular joint (PTFJ) dislocation is a rare injury that can disrupt the proximal tibia-fibula joint. The abnormalities in knee x-ray imaging can be subtle and difficult to detect, requiring careful assessment. This rare cause of lateral knee pain requires a high level of suspicion for diagnosis. Treatment is closed reduction; unstable PTFJ dislocations often require surgical intervention. CASE REPORT: A 17-year-old young man presented to the emergency department (ED) with right lateral knee pain and difficulty walking after colliding with another skier 2 days prior. The examination showed right lateral ecchymosis and tenderness over the lateral proximal fibula. He remained neurovascularly intact with a full passive and active range of motion. X-ray studies were obtained. The patient was referred by his outpatient orthopedic surgeon after the initial knee x-ray study was concerning for PTFJ dislocation and unsuccessful reduction. In the ED, the patient underwent moderate sedation and successful orthopedic-guided reduction via medial force on the lateral fibular head, while hyper-flexing the knee and holding the foot dorsiflexed and everted. Post-reduction radiographs showed improved proximal tibiofibular alignment without fracture. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: PTFJ dislocation is a rare injury that can be missed easily and requires a high level of suspicion when presented with an acute traumatic knee pain. Closed reduction of PTFJ dislocation can be achieved in the ED and early identification can prevent long-term sequelae.
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Dolor Agudo , Luxación de la Rodilla , Masculino , Humanos , Adolescente , Pierna , Tibia/lesiones , Luxación de la Rodilla/diagnóstico , Luxación de la Rodilla/cirugía , Peroné/diagnóstico por imagen , Peroné/lesiones , Articulación de la Rodilla/diagnóstico por imagenRESUMEN
Biseuphoids A (1) and B (2), two unprecedented ent-abietane-type diterpenoid dimers linked by monomeric blocks through C-17-C-12' and C-17-C-11', respectively, were isolated from Euphorbia fischeriana, along with their biogenesis related diterpenoid monomers, 17-hydroxyjolkinolide B (3), caudicifolin (4), and fischeriabietane C (5). Their structures were elucidated by extensive spectroscopy assisted by quantum chemical NMR and ECD calculations. The unusual dimeric skeletons are possibly derived from the adduct of diterpenoid monomers through Michael-like reactions. The novel dimers 1 and 2 exhibited inhibitory activities on soluble epoxide hydrolase (sEH) with IC50 values of 8.17 and 5.61 µM, respectively. Molecular dynamics studies illustrated that both 1 and 2 can occupy the catalytic pocket of sEH by forming stable hydrogen bonds with the key amino acid residues including Gln384, Asn378, Pro361, Ala365, Asn366, and Asn472.
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Diterpenos , Euphorbia , Abietanos/química , Diterpenos/química , Epóxido Hidrolasas/metabolismo , Euphorbia/química , Estructura Molecular , Raíces de Plantas/química , PolímerosRESUMEN
Current research has widely applied heteroatom doping for the promotion of catalyst activity in peroxymonosulfate (PMS) systems; however, the relationship between heteroatom doping and stimulated activation mechanism transformation is not fully understood. Herein, we introduce nitrogen and sulfur doping into a Co@rGO material for PMS activation to degrade tetracycline (TC) and systematically investigate how heteroatom doping transformed the activation mechanism of the original Co@rGO/PMS system. N was homogeneously inserted into the reduced graphene oxide (rGO) matrix of Co@rGO, inducing a significant increase in the degradation efficiency without affecting the activation mechanism transformation. Additionally, S doping converted Co3O4 to Co4S3 in Co@rGO and transformed the cooperative oxidation pathway into a single non-radical pathway with stronger intensity, which led to a higher stability against environmental interferences. Notably, based on density functional theory (DFT) calculations, we demonstrated that Co4S3 had a higher energy barrier for PMS adsorption and cleavage than Co3O4, and therefore, the radical pathway was not easily stimulated by Co4S3. Overall, this study not only illustrated the improvement due to the heteroatom doping of Co@rGO for TC degradation in a PMS system but also bridged the knowledge gap between the catalyst structure and degradation performance through activation mechanism transformation drawn from theoretical and experimental analyses.
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Nitrógeno , Peróxidos , Antibacterianos , Cobalto , Grafito , Nitrógeno/química , Óxidos , Peróxidos/química , Azufre , TetraciclinaRESUMEN
The role of step sites on nanocatalysts in the electrocatalytic dechlorination reaction (ECDR) was studied using 3 Pd nanocatalysts with different densities of step sites, which decreased in the order of: tetrahexahedral Pd{310} nanocrystals (THH Pd{310} NCs) > commercial Pd nanoparticles (Pd black) > cubic Pd{100} NCs. The two well-defined Pd NCs served as model catalysts and were prepared through the electrochemical square-wave potential (SWP) method. The toxic herbicide alachlor was first employed in this study as an objective probe to determine the dechlorination performance, which was quantified by the alachlor removal (Rala), the current efficiency (CEala), and the dechlorination selectivity (Sdes). The experimental results demonstrated that the THH Pd{310} NCs with abundant step sites exhibited much higher electrocatalytic performance compared to the cubic Pd{100} NCs with terrace sites. The combination of cyclic voltammetry studies, electrochemical in situ FTIR analysis, and density functional theory (DFT) calculations revealed that the adsorbed CîO bond and generated on the step sites could lower the C-Cl bond splitting barrier, leading to a high ECDR efficiency. Other chlorinated organics with an activated carbon atom were also investigated, which revealed that the superiority of the step sites toward Cl-C bond breaking was particular to the compounds with CîO bonds. This study provides a deep understanding of high actvitiy of step sites on Pd NCs in EHDC and a strategy to improve this important environmental electrocatalysis process.
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Bislangduoids A and B, a novel class of dimeric diterpenoids based on ent-abietanes tethered by C-17-C-15' bridge, were identified as trace components from a traditional Chinese medicine Euphorbia fischeriana (Langdu). Bislangduoid A features a highly oxidized scaffold incorporating a cage-like pentacyclic core. Their structures were elucidated by extensive spectroscopic techniques, electronic circular dichroism, and NMR calculations. The biosynthetic pathway for the dimeric skeleton and the unique caged moiety via Michael and acetal-formation reactions was proposed. Bislangduoid A showed pronounced cytotoxicity against HepG2 cells through the mitochondria-dependent apoptosis pathway.
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Antineoplásicos , Diterpenos , Euphorbia , Abietanos/química , Abietanos/farmacología , Diterpenos/química , Diterpenos/farmacología , Euphorbia/química , Estructura Molecular , Raíces de Plantas/química , PolímerosRESUMEN
A concept of spin plasmon, a collective mode of spin-density, in strongly correlated electron systems has been proposed since the 1930s. It is expected to bridge between spintronics and plasmonics by strongly confining the photon energy in the subwavelength scale within single magnetic-domain to enable further miniaturizing devices. However, spin plasmon in strongly correlated electron systems is yet to be realized. Herein, we present a new spin correlated-plasmon at room temperature in novel Mott-like insulating highly oriented single-crystalline gold quantum-dots (HOSG-QDs). Interestingly, the spin correlated-plasmon is tunable from the infrared to visible, accompanied by spectral weight transfer yielding a large quantum absorption midgap state, disappearance of low-energy Drude response, and transparency. Supported with theoretical calculations, it occurs due to an interplay of surprisingly strong electron-electron correlations, s-p hybridization and quantum confinement in the s band. The first demonstration of the high sensitivity of spin correlated-plasmon in surface-enhanced Raman spectroscopy is also presented.
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Gradient Learning (GL), aiming to estimate the gradient of target function, has attracted much attention in variable selection problems due to its mild structure requirements and wide applicability. Despite rapid progress, the majority of the existing GL works are based on the empirical risk minimization (ERM) principle, which may face the degraded performance under complex data environment, e.g., non-Gaussian noise. To alleviate this sensitiveness, we propose a new GL model with the help of the tilted ERM criterion, and establish its theoretical support from the function approximation viewpoint. Specifically, the operator approximation technique plays the crucial role in our analysis. To solve the proposed learning objective, a gradient descent method is proposed, and the convergence analysis is provided. Finally, simulated experimental results validate the effectiveness of our approach when the input variables are correlated.
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Alzheimer's disease (AD) is a common neurodegenerative disease. In an aging society, the high prevalence of AD and the low quality of life of AD patients create serious problems for individuals, families and the society. However, the etiology and pathogenesis of AD are still not fully understood. Age, genetics, environment and other factors are all relevant to AD, and treatment has not achieved satisfactory results. Recent studies have found that oral dysbiosis is closely related to the pathogenesis of AD, and that oral bacterial infection may be one of the causes of AD. Oral cavity is the largest microbial ecosystem of human body, and its homeostasis is critical to health. Bacterial infections caused by oral dysbiosis can directly and indirectly induce the metabolic imbalance of amyloid ß-protein (Aß) in the brain and the hyperphosphorylation of Tau protein. Then, the precipitation forms senile plaques and neurofibrillary tangles (NFTs) that damage neurons. Based on the latest research findings, we herein discussed the correlation between oral microbiota and the pathogenesis of AD and the mechanisms involved, as well as the pathogenic mechanism of main oral bacteria. In addition, we explored the potential application prospects of oral microbiota-targeted therapy.
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Enfermedad de Alzheimer , Microbiota , Enfermedades Neurodegenerativas , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/microbiología , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Humanos , Calidad de VidaRESUMEN
Two undescribed ent-abietane-type diterpenoid dimers with nonacyclic backbone formed by intermolecular [4 + 2] cycloaddition into a spirocyclic skeleton, bisfischoids A (1) and B (2), along with a known one fischdiabietane A (3), were identified from Euphorbia fischeriana Steud. Their structures were elucidated by extensive spectroscopic analysis, ECD and NMR calculation combined with DP4+ probability analysis, as well as X-ray diffraction. The anti-inflammatory potential of dimers 1-3 were examined using their inhibitory effects on soluble epoxide hydrolase (sEH), which revealed that 1 and 2 exhibited promising activities with inhibition constant (Ki) of 3.20 and 1.95 µM, respectively. Further studies of molecular docking and molecular dynamics indicated that amino acid residue Tyr343 in the catalytic cavity of sEH was the key site for their inhibitory function.
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Antiinflamatorios/farmacología , Medicamentos Herbarios Chinos/farmacología , Epóxido Hidrolasas/antagonistas & inhibidores , Euphorbia/química , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/aislamiento & purificación , Epóxido Hidrolasas/metabolismo , Humanos , Medicina Tradicional China , Estructura Molecular , Relación Estructura-ActividadRESUMEN
The genus Alisma contains 11 species distributed worldwide, of which at least two species (A. orientale [Sam.] Juzep. and A. plantago-aquatica Linn.) have been used as common herbal medicines. Secondary metabolites obtained from the genus Alisma are considered to be the material basis for the various biological functions and medicinal applications. In this review, we mainly focused on the recent investigations of secondary metabolites from plants of the genus Alisma and their biological activities, with the highlighting on the diversity of the chemical structures, the biosynthesis of interesting secondary metabolites, the biological activities, and the relationships between structures and bioactivities.
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Alisma/química , Fitoquímicos/uso terapéutico , Plantas Medicinales/química , HumanosRESUMEN
The Co center is active in electrochemical CO2 reduction (CO2RR), and its activity can be tuned by changing its coordination environment. However, the coordination number around the Co center cannot be readily changed in homogeneous systems owing to bimolecular decomposition of reduced low-coordinate Co species. Herein we report the systematic tuning of N atom numbers from 2 to 5 in the first coordination sphere around Co centers supported on two-dimensional metal-organic layers (MOLs) for the electrochemical CO2RR. The N atoms come from a combination of bipyridine, terpyridine, and phenylpyridine ligands. The Co centers are isolated and stabilized on the MOL to prevent bimolecular decomposition. All of the catalysts, denoted MOL-Co-Nx (x = 2-5), are active in reducing CO2 to CO electrochemically, but their activities are highly dependent on the number of coordinating N atoms. MOL-Co-N3 showed the highest current density of 2.3 A mg-1 with a CO Faradaic efficiency of 99% at an overpotential of only 380 mV. Density functional theory calculations attribute the high activity of the Co-N3 center to a balance of ligand field strength and open coordination site: the high ligand field strength promotes back-bonding, while the open coordination site allows HCO3- assistance, both of which accelerate C-O cleavage. MOLs thus provide a unique platform to systematically study the relationship between the coordination environment and the reactivity of open metal sites in electrocatalysis.