Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Front Cell Neurosci ; 18: 1379438, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38694537

RESUMO

Retinoic acid (RA), derived from vitamin A (retinol), plays a crucial role in modulating neuroplasticity within the adult brain. Perturbations in RA signaling have been associated with memory impairments, underscoring the necessity to elucidate RA's influence on neuronal activity, particularly within the hippocampus. In this study, we investigated the cell type and sub-regional distribution of RA-responsive granule cells (GCs) in the mouse hippocampus and delineated their properties. We discovered that RA-responsive GCs tend to exhibit a muted response to environmental novelty, typically remaining inactive. Interestingly, chronic dietary depletion of RA leads to an abnormal increase in GC activation evoked by a novel environment, an effect that is replicated by the localized application of an RA receptor beta (RARß) antagonist. Furthermore, our study shows that prolonged RA deficiency impairs spatial discrimination-a cognitive function reliant on the hippocampus-with such impairments being reversible with RA replenishment. In summary, our findings significantly contribute to a better understanding of RA's role in regulating adult hippocampal neuroplasticity and cognitive functions.

2.
Foods ; 12(21)2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37959035

RESUMO

As cross-border e-commerce platforms become increasingly integrated into the agricultural supply chain, the establishment of a sustainable supply chain ecosystem is of paramount importance. This study, grounded in the platform theory and the supply chain ecosystem theory, combines the grounded theory and the DEMATEL-ISM-MICMAC model to thoroughly analyze the complex mechanisms driving sustainable development. Utilizing the grounded theory, we construct a system of driving factors comprising five primary indicators and eighteen secondary indicators. The hybrid model reveals the interrelationships, significance, system hierarchy, and dependence-driving relationships among these factors. Notably, the driving factor system is categorized into a six-level hierarchical structure, encompassing profound elements, such as policy optimization and digital empowerment, as well as surface-level factors, such as simplification of customs procedures and consumer demand forecasting. Based on the analysis results, this research proposes a set of pathways to achieve the sustainability of the supply chain. These strategies involve improving cross-border agricultural e-commerce policy frameworks, enhancing digital-driven supply-demand coordination, strengthening logistics infrastructure and transparency, and cultivating brand influence. The study's findings not only enrich the relevant theories but also provide practical guidance for the coordinated advancement of economic, social, environmental, and resilient development. Furthermore, they are conducive to advancing the United Nations Sustainable Development Goals.

3.
Foods ; 12(17)2023 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-37685255

RESUMO

The organization and coordination of cross-border e-commerce platforms in agricultural product trading are continuously increasing, and the involvement of digital platforms has driven the integration and development of cross-border agricultural product supply chains with live-streaming e-commerce, effectively facilitating the comprehensive development of producers, sellers, and professional service providers within the ecosystem. However, despite the growing importance of this integration model in the market, there are still numerous unresolved issues from a supply chain perspective, and existing research provides relatively limited guidance on the effective operation of this integrated supply chain model. To address this gap in theoretical research, this study first delves into the essence and fundamental characteristics of sustainable cross-border agricultural product supply chains in the context of live streaming. Secondly, employing grounded theory as the primary research method and combining platform theory and ecosystem theory, an influencing factor system and an impact model for the development of sustainable cross-border agricultural product supply chains in the context of live streaming are constructed to gain a more comprehensive understanding of the complexity of this integrated supply chain model. Finally, from the perspectives of government agencies and practitioners, development pathways for sustainable cross-border agricultural product supply chains in the context of live-streaming e-commerce are proposed, aiming to enhance existing research and provide decision-making support for relevant stakeholders in formulating development strategies. The findings of this study contribute to expanding the research perspective on the ecosystem of live-streaming e-commerce and sustainable cross-border agricultural product supply chains, providing theoretical support for the establishment and operation of sustainable cross-border agricultural product supply chains in the context of live streaming. Additionally, it offers important references for promoting the sustainable development of live-streaming e-commerce and cross-border agricultural product supply chains, facilitating industry upgrading, global agricultural trade, and achieving mutually beneficial outcomes.

4.
Int J Mol Sci ; 24(10)2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37239816

RESUMO

Currently, polypropylene (PP) is used in various products, thus leading to high daily exposure in humans. Thus, it is necessary to evaluate the toxicological effects, biodistribution, and accumulation of PP microplastics in the human body. In this study, administration of two particle sizes of PP microplastics (approximately 5 and 10-50 µm) did not lead to any significant changes in several toxicological evaluation parameters, including body weight and pathological examination, compared with the control group in ICR mice. Therefore, the approximate lethal dose and no-observed-adverse-effect level of PP microplastics in ICR mice were established as ≥2000 mg/kg. Furthermore, we manufactured cyanine 5.5 carboxylic acid (Cy5.5-COOH)-labeled fragmented PP microplastics to monitor real-time in vivo biodistribution. After oral administration of the Cy5.5-COOH-labeled microplastics to the mice, most of the PP microplastics were detected in the gastrointestinal tract and observed to be out of the body after 24 h in IVIS Spectrum CT. Therefore, this study provides a new insight into the short-term toxicity, distribution, and accumulation of PP microplastics in mammals.


Assuntos
Polipropilenos , Poluentes Químicos da Água , Humanos , Animais , Camundongos , Polipropilenos/toxicidade , Microplásticos/toxicidade , Plásticos/toxicidade , Camundongos Endogâmicos ICR , Distribuição Tecidual , Poluentes Químicos da Água/toxicidade , Mamíferos
5.
Uisahak ; 32(3): 1043-1073, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-38273728

RESUMO

This article reviews how the crisis of doctorless villages in South Korea in the 1950s-70s was closely linked to the conscription system. In the second half of the twentieth century, South Korea's public health system faced a dual challenge: the colonial legacy of medical shortage and urban concentration, and the massive conscription of military doctors after the Korean War. The term 'doctorless village' was a signifier that reflected these historical contexts, symbolizing the chronic medical crisis in rural areas. Behind the crisis, there as a growing idea of reversing the constraints from conscription and using it as a solution for the doctorless village problem. Initially, the Ministry of Health and Social Affairs planned two alternatives to fill the gaps in the public health network. One was to station military doctors in doctorless villages, and the other was to dispatch civilian doctors in doctorless villages and exempt them from military service. After a series of doctor mobilizations since the May 16 coup, the medical community generally agreed with this plan and publicized it. They developed arguments for alternative services through public health work and strengthened its logic. By the 1970s, the plan culminated in the establishment of the current Public Health Doctor system. In terms of condition and momentum, the introduction of alternative service in other sectors, as well as the extension of the consensus among the government and medical community, accelerated this trend. As a result, the doctorless village crisis in South Korea, which had been a critical issue for a quarter of a century, entered a phase of resolution by utilizing the conscription system as its institutional foundation. It represented an aspect of the 'Korean' public health system characterized by the entanglement with conscription. However, another aspect to consider is that it has imposed additional limitation on medical care in rural areas by institutionalizing the public health system relying on mobilization and minimum budget.


Assuntos
Médicos , Saúde Pública , Humanos , Idoso , República da Coreia , Saúde Pública/história , Governo , Guerra da Coreia
6.
Sci Rep ; 12(1): 5321, 2022 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-35351899

RESUMO

Non-Darcy flows are a vital event leading to the inaccuracy in flow performance evaluation, particularly in the fractured wells in shale gas and tight oil deposits. The internal flow commonly indicates high flow rates at the early period of production, owing to the large geometric size of hydraulic fracture and high porosity in proppant packs. After that, the production flow rate decays steeply until the Darcy flow regime is attained. Therefore, accurate porous flow analyses from the Darcy to Forchheimer and then turbulent flow regimes are essential for optimal facility designs and economic productions in the unconventional deposits. The Comiti capillary model is recognised as the leading non-Darcy flow correlation for simple packed beds comprising mono-size grains. However, in actual hydraulic fractures, various types of proppants are used simultaneously and generally combined with numerous soil grains of different sizes and shapes. In this study, the Comiti model is modified by incorporating the effective diameters of the porous media and then examined for mixed complex multi-size packs. Subsequently, a novel type of non-Darcy flow equation is presented according to the logarithmic turbulent friction factor based on the physical variables determined only in the Darcy flow regime. The new equation presents accurate results for all the types of proppant packs under wide porosity and permeability ranges. The generalised non-Darcy flow correlation, which can be extensively employed from the Darcy to non-Darcy flow analyses, particularly beyond the Forchheimer regime, is presented for the accurate flow evaluation of the fractured reservoirs.

7.
Mol Psychiatry ; 25(6): 1215-1228, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-30837688

RESUMO

Most antidepressants, including selective serotonin reuptake inhibitors (SSRIs), initiate their drug actions by rapid elevation of serotonin, but they take several weeks to achieve therapeutic onset. This therapeutic delay suggests slow adaptive changes in multiple neuronal subtypes and their neural circuits over prolonged periods of drug treatment. Mossy cells are excitatory neurons in the dentate hilus that regulate dentate gyrus activity and function. Here we show that neuronal activity of hippocampal mossy cells is enhanced by chronic, but not acute, SSRI administration. Behavioral and neurogenic effects of chronic treatment with the SSRI, fluoxetine, are abolished by mossy cell-specific knockout of p11 or Smarca3 or by an inhibition of the p11/AnxA2/SMARCA3 heterohexamer, an SSRI-inducible protein complex. Furthermore, simple chemogenetic activation of mossy cells using Gq-DREADD is sufficient to elevate the proliferation and survival of the neural stem cells. Conversely, acute chemogenetic inhibition of mossy cells using Gi-DREADD impairs behavioral and neurogenic responses to chronic administration of SSRI. The present data establish that mossy cells play a crucial role in mediating the effects of chronic antidepressant medication. Our results indicate that compounds that target mossy cell activity would be attractive candidates for the development of new antidepressant medications.


Assuntos
Antidepressivos/administração & dosagem , Antidepressivos/farmacologia , Depressão/tratamento farmacológico , Depressão/psicologia , Fibras Musgosas Hipocampais/efeitos dos fármacos , Fibras Musgosas Hipocampais/fisiologia , Neurogênese/efeitos dos fármacos , Animais , Linhagem Celular , Depressão/patologia , Fluoxetina/administração & dosagem , Fluoxetina/farmacologia , Camundongos , Inibidores Seletivos de Recaptação de Serotonina/administração & dosagem , Inibidores Seletivos de Recaptação de Serotonina/farmacologia
8.
Mol Psychiatry ; 25(6): 1229-1244, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-30531938

RESUMO

Depression is a leading cause of disability. Current pharmacological treatment of depression is insufficient, and development of improved treatments especially for treatment-resistant depression is desired. Understanding the neurobiology of antidepressant actions may lead to development of improved therapeutic approaches. Here, we demonstrate that dopamine D1 receptors in the dentate gyrus act as a pivotal mediator of antidepressant actions in mice. Chronic administration of a selective serotonin reuptake inhibitor (SSRI), fluoxetine, increases D1 receptor expression in mature granule cells in the dentate gyrus. The increased D1 receptor signaling, in turn, contributes to the actions of chronic fluoxetine treatment, such as suppression of acute stress-evoked serotonin release, stimulation of adult neurogenesis and behavioral improvement. Importantly, under severely stressed conditions, chronic administration of a D1 receptor agonist in conjunction with fluoxetine restores the efficacy of fluoxetine actions on D1 receptor expression and behavioral responses. Thus, our results suggest that stimulation of D1 receptors in the dentate gyrus is a potential adjunctive approach to improve therapeutic efficacy of SSRI antidepressants.


Assuntos
Antidepressivos/farmacologia , Giro Denteado/metabolismo , Fluoxetina/farmacologia , Receptores de Dopamina D1/metabolismo , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL
9.
J Org Chem ; 84(20): 12913-12924, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31401836

RESUMO

Thiazole-containing π-conjugated moieties are important structural units in the development of new electronic and photochromic materials. We have developed a Pd-catalyzed syn-hydroarylation reaction of diaryl alkynes with thiazoles that provides access to thiazole-containing triarylethylenes. Pd(II) complexes derived from Pd(0) species and carboxylic acids facilitated C-H functionalization of the unsubstituted thiazole with high C5 selectivity. The catalytic system was also compatible with other azoles, such as oxazoles and a pyrazole, allowing the stereoselective syntheses of various trisubstituted olefins.

10.
Cell Signal ; 44: 138-147, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29329782

RESUMO

Lysophosphatidic acid (LPA) has been implicated in the pathology of human ovarian cancer. This phospholipid elicits a wide range of cancer cell responses, such as proliferation, trans-differentiation, migration, and invasion, via various G-protein-coupled LPA receptors (LPARs). Here, we explored the cellular signaling pathway via which LPA induces migration of ovarian cancer cells. LPA induced robust phosphorylation of ezrin/radixin/moesin (ERM) proteins, which are membrane-cytoskeleton linkers, in the ovarian cancer cell line OVCAR-3. Among the LPAR subtypes expressed in these cells, LPA1 and LPA2, but not LPA3, induced phosphorylation of ERM proteins at their C-termini. This phosphorylation was dependent on the Gα12/13/RhoA pathway, but not on the Gαq/Ca2+/PKC or Gαs/adenylate cyclase/PKA pathway. The activated ERM proteins mediated cytoskeletal reorganization and formation of membrane protrusions in OVCAR-3 cells. Importantly, LPA-induced migration of OVCAR-3 cells was completely abolished not only by gene silencing of LPA1 or LPA2, but also by overexpression of a dominant negative ezrin mutant (ezrin-T567A). Taken together, this study demonstrates that the LPA1/LPA2/ERM pathway mediates LPA-induced migration of ovarian cancer cells. These findings may provide a potential therapeutic target to prevent metastatic progression of ovarian cancer.


Assuntos
Carcinoma Epitelial do Ovário/patologia , Proteínas do Citoesqueleto/metabolismo , Lisofosfolipídeos/metabolismo , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/metabolismo , Neoplasias Ovarianas/patologia , Receptores de Ácidos Lisofosfatídicos/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Feminino , Humanos , Fosforilação , Transdução de Sinais , Proteína rhoA de Ligação ao GTP/metabolismo
11.
Asian-Australas J Anim Sci ; 27(3): 383-90, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25049965

RESUMO

A 15-wk feeding trial was conducted to examine the supplemental effects of Barodon on growth performance, gastrointestinal histology, feed digestibility and innate immunity in olive founder. A basal commercial diet was used as a control and two other diets were prepared by spraying 0.1% or 0.2% of Barodon. Triplicate groups of fish (BW, 145 g) were fed one of the test diets to apparent satiation twice daily. At the end of the feeding trial, fish growth performance was not significantly affected by dietary treatments; however, feed utilization was significantly improved (linear and quadratic, p<0.05) by Barodon supplementation. Significantly higher (p<0.05) survival rates were obtained in fish fed Barodon containing diets. Hepatosomatic index increased significantly in Barodon treated groups. Also, the use of Barodon resulted in significant increase (linear and quadratic, p<0.05) of intestine length and number of goblet cells. Significantly higher (Quadratic, p<0.05) apparent digestibility coefficient of DM was obtained by supplementation of Barodon. Lysozyme and myeloperoxidase activities increased quadratically and linearly, respectively, in Barodon treated fish. Also, significantly higher (linear and quadratic, p<0.05) superoxide dismutase activity was found in Barodon fed fish. The findings in this study show that inclusion of Barodon in diets for olive flounder improves feed utilization and digestibility, and positively affects digestive tract histology and innate immunity.

12.
Biosci Biotechnol Biochem ; 73(12): 2576-82, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19966492

RESUMO

Dry powder formulations for pulmonary delivery are attractive because many issues of solubility and stability can be minimized. Human insulin microcrystals with lactose carriers were produced for pulmonary delivery. The average particle diameter was 2.3 microm, with a narrow, monodispersed size distribution. The percentages of high molecular weight proteins (%HMWPs), other insulin-related compounds (%OIRCs), and A-21 desamido insulin (%D(es)) were very low throughout the microcrystal preparation process. Administration of the microcrystal powder by intratracheal insufflation significantly reduced the blood glucose levels of Sprague-Dawley rats. The percent minimum reductions of the blood glucose concentration (%MRBG) produced by the insulin microcrystal powder and by an insulin solution reached 40.4% and 33.4% of the initial glucose levels respectively, and their bioavailability relative to subcutaneous injection (F) was 15% and 10% respectively. These results confirm that the insulin microcrystal powder prepared is suitable for pulmonary delivery in an effective dosage form.


Assuntos
Portadores de Fármacos/química , Insulina/administração & dosagem , Insulina/química , Lactose/química , Pulmão/metabolismo , Animais , Glicemia/metabolismo , Varredura Diferencial de Calorimetria , Vias de Administração de Medicamentos , Humanos , Hipoglicemia/sangue , Hipoglicemia/induzido quimicamente , Insulina/farmacologia , Masculino , Tamanho da Partícula , Ratos , Ratos Sprague-Dawley , Traqueia
13.
J Agric Food Chem ; 57(15): 6596-602, 2009 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-19722567

RESUMO

Plant essential oils from 26 plant species were tested for their insecticidal activities against the Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with source, exposure time, and concentration. Among the essential oils tested, strong insecticidal activity was observed with the essential oils of ajowan ( Trachyspermum ammi ), allspice ( Pimenta dioica ), caraway ( Carum carvi ), dill ( Anethum graveolens ), geranium ( Pelargonium graveolens ), and litsea ( Litsea cubeba ). The composition of six essential oils was identified by using gas chromatography-mass spectrometry. The compounds thus identified were tested individually for their insecticidal activities against Japanese termites. Responses varied in a dose-dependent manner for each compound. Phenol compounds exhibited the strongest insecticidal activity among the test compounds; furthermore, alcohol and aldehyde groups were more toxic than hydrocarbons. The essential oils and compounds described herein merit further study as potential fumigants for termite control.


Assuntos
Inseticidas/farmacologia , Isópteros/efeitos dos fármacos , Magnoliopsida/química , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Animais , Fumigação , Controle de Insetos , Inseticidas/química , Óleos Voláteis/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Óleos de Plantas/química
14.
J Hazard Mater ; 163(2-3): 729-34, 2009 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-18755545

RESUMO

A process was developed to recover nitric acid from the waste stream of wafer industry using solvent extraction technique. Tributyl phosphate (TBP) was selected among several extractants because of its better selectivity towards HNO(3), overall superiority in operation, favorable physical properties and economics. The waste solution containing 260 g/L CH(3)COOH, 460 g/L HNO(3), 113 g/L HF and 19.6g/L Si was used as feed solution for process optimization. In the pre-treatment stage >99% silicon and hydrofluoric acid was precipitated out as Na(2)SiF(6). Equilibrium conditions for HNO(3) recovery were optimized from the batch test results as: four stages of extraction at an organic:aqueous (O:A) ratio of 3, four stages of scrubbing at O:A ratio of 5 and five stages of stripping at an O:A ratio of 1.5. The extraction of HNO(3) was suppressed by the presence of acetic acid (HAc) in the feed solution. To examine the feasibility of the extraction system a continuous operation was carried out for 200 h using a multistage mixer-settler. The concentration of pure HNO(3) recovered was 235 g/L with a purity of 99.8%.


Assuntos
Resíduos Industriais , Ácido Nítrico/isolamento & purificação , Organofosfatos , Soluções , Solventes
15.
J Hazard Mater ; 162(2-3): 1278-84, 2009 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-18639982

RESUMO

Recovery of acetic acid (HAc) from the waste etching solution discharged from silicon wafer manufacturing process has been attempted by using solvent extraction process. For this purpose 2-ethylhexyl alcohol (EHA) was used as organic solvent. In the pre-treatment stage >99% silicon and hydrofluoric acid was removed from the solution by precipitation. The synthesized product, Na(2)SiF(6) having 98.2% purity was considered of commercial grade having good market value. The waste solution containing 279 g/L acetic acid, 513 g/L nitric acid, 0.9 g/L hydrofluoric acid and 0.030 g/L silicon was used for solvent extraction study. From the batch test results equilibrium conditions for HAc recovery were optimized and found to be 4 stages of extraction at an organic:aqueous (O:A) ratio of 3, 4 stages of scrubbing and 4 stages of stripping at an O:A ratio of 1. Deionized water (DW) was used as stripping agent to elute HAc from organic phase. In the whole batch process 96.3% acetic acid recovery was achieved. Continuous operations were successfully conducted for 100 h using a mixer-settler to examine the feasibility of the extraction system for its possible commercial application. Finally, a complete process flowsheet with material balance for the separation and recovery of HAc has been proposed.


Assuntos
Ácido Acético/isolamento & purificação , Ácidos/química , Semicondutores , Solventes/química , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA