Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
J Tribol ; 136(3): 0317031-3170313, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25053867

RESUMEN

Nature has long been an important source of inspiration for mankind to develop artificial ways to mimic the remarkable properties of biological systems. In this work, a new method was explored to fabricate a biomimetic engineering surface comprising both the shark-skin, the shark body denticle, and rib morphology. It can help reduce water resistance and the friction contact area as well as accommodate lubricant. The lubrication theory model was established to predict the effect of geometric parameters of a biomimetic surface on tribological performance. The model has been proved to be feasible to predict tribological performance by the experimental results. The model was then used to investigate the effect of the grid textured surface on frictional performance of different geometries. The investigation was aimed at providing a rule for deriving the design parameters of a biomimetic surface with good lubrication characteristics. Results suggest that: (i) the increase in depression width ratio [Formula: see text] decreases its corresponding coefficient of friction, and (ii) the small coefficient of friction is achievable when [Formula: see text] is beyond 0.45. Superposition of depth ratio Γ and angle's couple under the condition of [Formula: see text] < 0.45 affects the value of friction coefficient. It shows the decrease in angle decreases with the increase in dimension depth [Formula: see text].

2.
Adv Sci (Weinh) ; 11(8): e2306128, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38039489

RESUMEN

Sympathetic innervation plays a crucial role in maintaining energy balance and contributes to metabolic pathophysiology. Recent evidence has begun to uncover the innervation landscape of sympathetic projections and sheds light on their important functions in metabolic activities. Additionally, the immune system has long been studied for its essential roles in metabolic health and diseases. In this review, the aim is to provide an overview of the current research progress on the sympathetic regulation of key metabolic organs, including the pancreas, liver, intestine, and adipose tissues. In particular, efforts are made to highlight the critical roles of the peripheral nervous system and its potential interplay with immune components. Overall, it is hoped to underscore the importance of studying metabolic organs from a comprehensive and interconnected perspective, which will provide valuable insights into the complex mechanisms underlying metabolic regulation and may lead to novel therapeutic strategies for metabolic diseases.


Asunto(s)
Hígado , Páncreas , Tejido Adiposo , Intestinos
3.
Protein Cell ; 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38752989

RESUMEN

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder in which patients experience recurrent eczematous lesions and intense itching. The colonization of Staphylococcus aureus (S. aureus) is correlated with the severity of the disease, but its role in AD development remains elusive. Using single-cell RNA sequencing, we uncovered that keratinocytes activate a distinct immune response characterized by induction of Il24 when exposed to methicillin-resistant S. aureus (MRSA). Further experiments using animal models showed that the administration of recombinant IL-24 protein worsened AD-like pathology. Genetic ablation of Il24 or the receptor Il20rb in keratinocytes alleviated allergic inflammation and atopic march. Mechanistically, IL-24 acted through its heterodimeric receptors on keratinocytes and augmented the production of IL-33, which in turn aggravated type 2 immunity and AD-like skin conditions. Overall, these findings establish IL-24 as a critical factor for onset and progression of AD and a compelling therapeutic target.

4.
Sci Data ; 11(1): 340, 2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38580722

RESUMEN

Despite the rapid advances in sequencing technology, limited genomic resources are currently available for phytophagous spider mites, which include many important agricultural pests. One of these pests is Tetranychus piercei (McGregor), a serious banana pest in East Asia exhibiting remarkable tolerance to high temperature. In this study, we assembled a high-quality genome of T. piercei using a combination of PacBio long reads and Illumina short reads sequencing. With the assistance of chromatin conformation capture technology, 99.9% of the contigs were anchored into three pseudochromosomes with a total size of 86.02 Mb. Repetitive elements, accounting for 14.16% of this genome (12.20 Mb), are predominantly composed of long-terminal repeats (30.7%). By combining evidence of ab initio prediction, transcripts, and homologous proteins, we annotated 11,881 protein-coding genes. Both the genome and proteins have high BUSCO completeness scores (>94%). This high-quality genome, along with reliable annotation, provides a valuable resource for investigating the high-temperature tolerance of this species and exploring the genomic basis that underlies the host range evolution of spider mites.


Asunto(s)
Tetranychidae , Animales , Cromosomas , Genoma , Genómica , Anotación de Secuencia Molecular , Filogenia , Secuencias Repetitivas de Ácidos Nucleicos , Tetranychidae/genética
5.
Yao Xue Xue Bao ; 48(1): 32-7, 2013 Jan.
Artículo en Zh | MEDLINE | ID: mdl-23600138

RESUMEN

This study is to offer a clinical pain-depression dyad therapy of ferulic acid, the pain-depression dyad induced by reserpine was established and the dose-effect relationship of ferulic acid on ameliorating pain-depression dyad was explored. Mice were randomly divided into control group, reserpine + vechile and reserpine + ferulic acid (5, 10, 20, 40 and 80 mg x kg(-1)) groups. The reserpine treated mice were tested with thermal hyperalgesia, mechanicial allodynia and forced swimming tests, and the SOD and NO levels of hippocampus and frontal cortex were measured. Moreover, the HPLC-ECD was used to detect the changes of central monoamines concentrations. Compared with control group, reserpine can induce a significant decrease in the nociceptive threshold and increase in the immobility time of the forced swimming test. The results suggested that reserpine significantly increased the level of nitrite in hippocampus and frontal cortex and reduced the levels of SOD, 5-HT and NE in these two brain regions. However, these indexes can be a dose-dependently reversed by ferulic acid (5, 10, 20, 40 and 80 mg x kg(-1)). Ferulic acid can reverse pain-depression dyad, especially at the dose of 80 mg x kg(-1). In addition, it can influence oxidative stress and monoamine level.


Asunto(s)
Antidepresivos/farmacología , Ácidos Cumáricos/farmacología , Depresión/metabolismo , Depresión/fisiopatología , Dolor/metabolismo , Dolor/fisiopatología , Animales , Antidepresivos/administración & dosificación , Ácidos Cumáricos/administración & dosificación , Depresión/inducido químicamente , Depresión/complicaciones , Dopamina/metabolismo , Relación Dosis-Respuesta a Droga , Lóbulo Frontal/metabolismo , Hipocampo/metabolismo , Hiperalgesia/fisiopatología , Masculino , Ratones , Ratones Endogámicos ICR , Óxido Nítrico/metabolismo , Norepinefrina/metabolismo , Dolor/inducido químicamente , Dolor/complicaciones , Dimensión del Dolor , Distribución Aleatoria , Reserpina/efectos adversos , Serotonina/metabolismo , Superóxido Dismutasa/metabolismo , Natación/fisiología
6.
PLoS One ; 18(1): e0280919, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36693072

RESUMEN

The effectiveness of the blended teaching model in improving university students' English learning achievement has been frequently reported in China in the post-pandemic era. However, such research has seldom explored the students' entire EFL (English as a foreign language) learning process and mechanism from the perspective of learners within this model. This study therefore used the 3P (presage, process and product) teaching and learning theory to explore the mediating role of learning methods (i.e., learning engagement and academic procrastination) in the relationship between learning preparation (i.e., academic self-concept and course experience) and learning achievement within the Chinese EFL blended teaching context from the perspective of learners. In this study, 942 Chinese university students (male: N = 447; female: N = 495) participated in a survey and completed electronic questionnaires on EFL-related academic self-concept, learning engagement, academic procrastination, and learning achievement. The data were analyzed using AMOS software and a structural equation modeling (SEM) technique. The results showed that both students' academic self-concept and course experience directly and positively predicted their English learning achievement. Moreover, students' academic self-concept of learning achievement was partially mediated by learning engagement and academic procrastination, whereas the effect of course experience on learning achievement was fully mediated by learning engagement and academic procrastination. After discussing these findings, suggestions as well as limitations for future studies will be given.


Asunto(s)
COVID-19 , Humanos , Masculino , Femenino , Universidades , COVID-19/epidemiología , Aprendizaje , Estudiantes , Lenguaje
7.
Front Psychol ; 14: 1278827, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38259560

RESUMEN

Introduction: With the rapid development of technology and the evolution of educational ideas, the blended learning model has become the new norm in higher education. Therefore, based on Biggs' learning process theory, this study aims to investigate the relationships between learning experience, learning approaches, and learning satisfaction of university students within the Chinese blended learning context to explore the dynamic process and mechanism of blended learning. Methods: The Chinese modified versions of the Self-Rating Scale of Self-Directed Learning, the Course Experience Questionnaire, and the Revised Study Process Questionnaire were administered to 939 Chinese university first-grade students (444 men, 495 women). The data were analyzed by using the covariance-based structural equation modeling (CB-SEM) technique. Results: The results demonstrated that, among Chinese university students, there were significant correlations between the self-directed learning experience, the course experience, the deep learning approach, the surface learning approach, and learning satisfaction. Additionally, the learning approaches mediated the association between the self-directed learning experience and learning satisfaction and between the course experience and learning satisfaction. Conclusion: This study provides insight into the facilitative effect of university students' self-directed learning experience and course experience on their learning satisfaction and how this effect is triggered through the mediating role of different learning approaches with the blended learning context. This study shows the learning behaviors and psychology in a blended learning environment, thus revealing the new learning characteristics of university students by integrating the self-learning characteristics of blended learning into the framework of learning process theory. The findings contribute to assisting blended learning providers in delivering targeted interventions to enhance students' learning satisfaction.

8.
Int Immunopharmacol ; 120: 110317, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37207447

RESUMEN

Membranous nephropathy (MN) is one of the most common causes of non-diabetic nephrotic syndrome in adults. About 80% of cases are renal limited (primary MN) and 20% are associated with other systemic diseases or exposures (secondary MN). Autoimmune reaction is the main pathogenic factor of MN, and the discovery of autoantigens including the phospholipase A2 receptor and thrombospondin type-1 domain-containing protein 7A has led to new insights into the pathogenesis, they can induce humoral immune responses led by IgG4 makes them suitable for the diagnosis and monitoring of MN. In addition, complement activation, genetic susceptibility genes and environmental pollution are also involved in MN immune response. In clinical practice, due to the spontaneous remission of MN, the combination of supportive therapy and pharmacological treatment is widely used. Immunosuppressive drugs are the cornerstone of MN treatment, and the dangers and benefits of this approach vary from person to person. In summary, this review provides a more comprehensive review of the immune pathogenesis, interventions and unresolved issues of MN in the hope of providing some new ideas for clinical and scientific researchers in the treatment of MN.


Asunto(s)
Glomerulonefritis Membranosa , Síndrome Nefrótico , Adulto , Humanos , Glomerulonefritis Membranosa/tratamiento farmacológico , Trombospondinas/metabolismo , Receptores de Fosfolipasa A2/metabolismo , Riñón/patología , Síndrome Nefrótico/complicaciones , Autoanticuerpos
9.
World J Stem Cells ; 15(4): 209-220, 2023 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-37181004

RESUMEN

Cancer stem cells (CSCs) are the main cause of tumor growth, invasion, metastasis and recurrence. Recently, CSCs have been extensively studied to identify CSC-specific surface markers as well as signaling pathways that play key roles in CSCs self-renewal. The involvement of CSCs in the pathogenesis of gastrointestinal (GI) cancers also highlights these cells as a priority target for therapy. The diagnosis, prognosis and treatment of GI cancer have always been a focus of attention. Therefore, the potential application of CSCs in GI cancers is receiving increasing attention. This review summarizes the role of CSCs in GI cancers, focusing on esophageal cancer, gastric cancer, liver cancer, colorectal cancer, and pancreatic cancer. In addition, we propose CSCs as potential targets and therapeutic strategies for the effective treatment of GI cancers, which may provide better guidance for clinical treatment of GI cancers.

10.
Phytomedicine ; 114: 154763, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37001295

RESUMEN

BACKGROUND: Membranous nephropathy (MN) is one of the cardinal causes of nephrotic syndrome in adults, but an adequate treatment regimen is lacking. PURPOSE: We assessed the effect of Moshen granule (MSG) on patients with MN and cationic bovine serum albumin (CBSA)-induced rats. We further identified the bioactive components of MSG and revealed the underlying molecular mechanism of its renoprotective effects. METHODS: We determined the effect of MSG on patients with MN and CBSA-induced rats and its components on podocyte injury in zymosan-activated serum (ZAS)-elicited podocytes and revealed their regulatory mechanism on the Wnt/ß-catenin/renin-angiotensin system (RAS) signalling axis. RESULTS: MSG treatment improved renal function and reduced proteinuria in MN patients and significantly reduced proteinuria and preserved the protein expression of podocin, nephrin, podocalyxin and synaptopodin in CBSA-induced MN rats. Mechanistically, MSG treatment significantly inhibited the protein expression of angiotensinogen, angiotensin converting enzyme and angiotensin II type 1 receptor, which was accompanied by inhibition of the protein expression of Wnt1 and ß-catenin and its downstream gene products, including Snail1, Twist, matrix metalloproteinase-7, plasminogen activator inhibitor-1 and fibroblast-specific protein 1, in CBSA-induced MN rats. We further identified 81 compounds, including astragaloside IV (AGS), calycosin, barleriside A and geniposidic acid, that preserve the podocyte-specific protein expression in ZAS-induced podocytes. Among these four compounds, AGS exhibited the strongest inhibitory effects on podocyte protein expression. AGS treatment significantly inhibited the protein expression of RAS components and Wnt1 and ß-catenin and its downstream gene products in ZAS-induced podocytes. In contrast, the inhibitory effect of AGS on podocyte-specific proteins, ß-catenin downstream gene products and RAS components was partially abolished in ZAS-induced podocytes treated with ICG-001 and ß-catenin siRNA. CONCLUSION: This study first demonstrates that AGS mitigates podocyte injury by inhibiting the activation of RAS signalling via the Wnt1/ß-catenin pathway by both pharmacological and genetic methods. Therefore, AGS might be considered a new ß-catenin inhibitor that inhibits the Wnt1/ß-catenin pathway to retard MN in patients.


Asunto(s)
Glomerulonefritis Membranosa , Sistema Renina-Angiotensina , Ratas , Animales , beta Catenina/metabolismo , Proteinuria , Vía de Señalización Wnt
11.
Insect Sci ; 30(5): 1208-1228, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37279769

RESUMEN

The phytophagous mite Tetranychus truncatus is a serious pest in East Asia but has a relatively narrower host range than the pest mite Tetranychus urticae, which can feed on over 1200 plant species. Here, we generated a high-quality chromosomal level genome of T. truncatus and compared it with that of T. urticae, with an emphasis on the genes related to detoxification and chemoreception, to explore the genomic basis underlying the evolution of host range. We also conducted population genetics analyses (in 86 females from 10 populations) and host transfer experiments (in 4 populations) to investigate transcription changes following transfer to a low-quality host (Solanum melongena, eggplant), and we established possible connections between fitness on eggplant and genes related to detoxification and chemoreception. We found that T. truncatus has fewer genes related to detoxification, transport, and chemoreception than T. urticae, with a particularly strong reduction in gustatory receptor (GR) genes. We also found widespread transcriptional variation among T. truncatus populations, which varied in fitness on eggplant. We characterized selection on detoxification-related genes through ω values and found a negative correlation between expression levels and ω values. Based on the transcription results, as well as the fitness and genetic differences among populations, we identified genes potentially involved in adaptation to eggplant in T. truncatus. Our work provides a genomic resource for this pest mite and new insights into mechanisms underlying the adaptation of herbivorous mites to host plants.

12.
Ageing Res Rev ; 79: 101662, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35688331

RESUMEN

Aging promotes chronic inflammation, which contributes to fibrosis and decreases organ function. Fibrosis, the excessive synthesis and deposition of extracellular matrix components, is the main cause of most chronic diseases including aging-related organ failure. Organ fibrosis in the heart, liver, and kidneys is the final manifestation of many chronic diseases. The aryl hydrocarbon receptor (AHR) is a cytoplasmic receptor and highly conserved transcription factor that is activated by a variety of small-molecule ligands to affect a wide array of tissue homeostasis functions. In recent years, mounting evidence has revealed that AHR plays an important role in multi-organ fibrosis initiation, progression, and therapy. In this review, we summarise the relationship between AHR and the pathogenesis of aging-related tissue fibrosis, and further discuss how AHR modulates tissue fibrosis by regulating transforming growth factor-ß signalling, immune response, and mitochondrial function, which may offer novel targets for the prevention and treatment of this condition.


Asunto(s)
Envejecimiento , Receptores de Hidrocarburo de Aril , Envejecimiento/patología , Fibrosis/patología , Humanos , Riñón/patología , Hígado/patología
13.
Asian J Psychiatr ; 73: 103118, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35468481

RESUMEN

BACKGROUND: Mood-incongruent psychosis during bipolar disorder has been associated with poor outcomes. However, it remains unknown whether this is secondary to persistent affective or psychotic symptoms or both. METHOD: Sixty-eight patients with bipolar disorder between the ages of 16 and 45 were recruited during their first psychiatric hospitalization for mania. These patients were evaluated using structured and semi-structured clinical interview then followed longitudinally. Outcomes during the first twenty-four months of follow-up were compared between patients with mood-incongruent psychosis and those without (i.e., patients with mood-congruent psychosis or no psychosis) during the index manic episode. Specifically, ratings of the percent of weeks during follow-up with the duration of mood incongruent psychotic symptom, any psychotic symptom, affective syndromes, and scores of global outcomes were compared. RESULTS: Comparing the 24-month follow-up results between the two groups, patients with mood incongruent psychotic symptoms had a lower global functional rating scale, efficacy index, while the duration of mood incongruent psychotic symptom, any psychotic symptom, and complete affective symptom showed statistically significant differences between the two groups. There were also statistically significant differences between the two groups in the duration of mood stabilizers, and antidepressants use, typical antipsychotics, and atypical antipsychotics. Partial correlation analysis reveals the scores of the global assessment of functioning scale (GAF) after 24 months showed a significant negative correlation with the length of time of incongruent psychotic symptoms. Still, the correlation was intermediate (correlation coefficients less than 0.5,r2 = -0.471, P < 0.001). CONCLUSION: Mood-incongruent psychosis that occurs during the first manic episode appears to predict an increased likelihood of persistent psychotic symptoms during the subsequent twenty-four months. This persistence of psychosis is associated with a worse overall course of illness than patients without mood-incongruent psychosis. LIMITATIONS: These results apply to a relatively short outcome period, and the sample size is relatively small.


Asunto(s)
Antipsicóticos , Trastorno Bipolar , Trastornos Psicóticos , Adolescente , Adulto , Antipsicóticos/uso terapéutico , Trastorno Bipolar/complicaciones , Trastorno Bipolar/diagnóstico , Trastorno Bipolar/tratamiento farmacológico , Estudios de Seguimiento , Humanos , Manía , Persona de Mediana Edad , Trastornos Psicóticos/complicaciones , Trastornos Psicóticos/etiología , Adulto Joven
14.
Acad Pediatr ; 22(3): 402-412, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34757026

RESUMEN

BACKGROUND AND OBJECTIVES: This intensive longitudinal study investigated 1) the extent to which engaging in social distancing predicted adolescents' same- and next-day stress and positive affect and 2) whether COVID-19-related knowledge and exercise moderated these links during statewide stay-at-home orders that mandated schools and nonessential businesses to close during the coronavirus pandemic. METHODS: Over the course of 28 days at the onset of the COVID-19 pandemic, a nationwide sample of 349 adolescents (Mean age = 15.0; 40% male; 44% Black, 39% White, 9% Latinx, 6% Asian American, 2% Native American) completed daily surveys about their social distancing behaviors, knowledge about the coronavirus, and exercise habits. Analysis was conducted on a total of 9372 assessments using longitudinal multilevel modeling approaches. RESULTS: Daily engagement in social distancing predicted increases in adolescents' stress and decreases in their positive affect. Practical knowledge about COVID-19 and daily exercise moderated these links. Specifically, practical knowledge and exercise weakened the positive link between social distancing and stress as well as the negative link between social distancing and positive affect. CONCLUSIONS: Adolescents' practical knowledge and exercise have the potential to buffer against the adverse effects of social distancing on stress and positive affect. However, it is critical for health care providers to recognize that youth are experiencing significant stress due to the disruption of developmentally normal patterns of social interaction. Pediatricians should focus on explaining the rationale behind social distancing while encouraging exercise as an adaptive coping mechanism that has benefits for psychological well-being.


Asunto(s)
COVID-19 , Pandemias , Adaptación Psicológica , Adolescente , Femenino , Humanos , Estudios Longitudinales , Masculino , Distanciamiento Físico
15.
Risk Manag Healthc Policy ; 14: 3159-3166, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34349576

RESUMEN

BACKGROUND: It is very important to determine the risk of patients developing severe or critical COVID-19, but most of the existing risk prediction models are established using conventional regression models. We aim to use machine learning algorithms to develop predictive models and compare predictive performance with logistic regression models. METHODS: The medical record of 161 COVID-19 patients who were diagnosed January-April 2020 were retrospectively analyzed. The patients were divided into two groups: asymptomatic-moderate group (132 cases) and severe or above group (29 cases). The clinical features and laboratory biomarkers of these two groups were compared. Machine learning algorithms and multivariate logistic regression analysis were used to construct two COVID-19 risk stratification prediction models, and the area under the curve (AUC) was used to compare the predictive efficacy of these two models. RESULTS: A machine learning model was constructed based on seven characteristic variables: high sensitivity C-reactive protein (hs-CRP), procalcitonin (PCT), age, neutrophil count (Neuc), hemoglobin (HGB), percentage of neutrophils (Neur), and platelet distribution width (PDW). The AUC of the model was 0.978 (95% CI: 0.960-0.996), which was significantly higher than that of the logistic regression model (0.827; 95% CI: 0.724-0.930) (P=0.002). Moreover, the machine learning model's sensitivity, specificity, and accuracy were better than those of the logistic regression model. CONCLUSION: Machine learning algorithms improve the accuracy of risk stratification in patients with COVID-19. Using detection algorithms derived from these techniques can enhance the identification of critically ill patients.

16.
J Adolesc Health ; 68(6): 1059-1066, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33858762

RESUMEN

PURPOSE: Adolescents are at risk for violating COVID-19 social distancing measures owing to salient developmental needs for autonomy and relatedness. This intensive longitudinal study investigated the initiation and sustainment of adolescents' daily social distancing behaviors. METHODS: Focus group and daily-diary approaches were used to collect 6,216 assessments from a nationwide American adolescent sample (n = 444; Mage = 15.1; 40% male; 42% black/African American, 40% white/European American, 10% Latinx, 6% Asian American, 2% Native American) over the course of 14 days at the onset of the COVID-19 pandemic. RESULTS: When adolescents were motivated by preventing others from getting sick, they were more likely to engage in social distancing (same day: B = .50, SE = .09, 95% confidence interval [CI] [.32, .68] p < .001; next day: B = .49, SE = .09, 95% CI [.31, .67] p < .001). Daily social support from friends (same day: B = .04, SE = .02, 95% CI [.01, .08] p < .05; next day: B = .08, SE = .02, 95% CI [.05, .12] p < .001), connectedness with friends via technology (same day: B = .23, SE = .04, 95% CI [.14, .32] p < .001; next day: B = .12, SE = .05, 95% CI [.03, .21] p < .001), and practical knowledge about ways to prevent contracting and transmitting COVID-19 (same day: B = .12, SE = .02, 95% CI [.08, .17] p < .001; next day: B = .05, SE = .02, 95% CI [.01, .10] p < .05) positively predicted adolescents' same- and next-day engagement in social distancing. CONCLUSIONS: Adolescents who were motivated by the desire to protect others were more likely to engage in social distancing. In addition, adolescents who learned about preventative health behaviors for mitigating COVID-19, received peer support, and remained virtually connected with friends were more likely to engage in daily social distancing at the onset of the pandemic.


Asunto(s)
COVID-19/prevención & control , COVID-19/psicología , Motivación , Pandemias , Distanciamiento Físico , Adolescente , COVID-19/epidemiología , Femenino , Humanos , Estudios Longitudinales , Masculino , Salud Pública , SARS-CoV-2 , Estados Unidos
17.
Materials (Basel) ; 14(7)2021 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-33916343

RESUMEN

This paper reports a novel pocket-textured surface for improving the tribological properties of point contact under starved lubrication by possibly storing and releasing oil, and homogenizing the surface contact pressure. The ball-on-disk experimental results confirmed the coefficient of friction (COF) and wear reduction effect of such pocket-texturing. The maximum reduction rate was 40% compared with a flat surface under the same operating conditions. Analyses on experimental results attributed the oil storage effect and enhanced the secondary lubrication effect within the starved lubrication state, to become the main mechanism. In addition, the plate elasticity and the Hertzian contact principles were employed to estimate the pressure and the load acting on the surface. The experimental results and numerical analysis substantiated the design of pocket-textured surface, making it likely to enlarge about 50% of contact surface and to reduce 90% of equivalent stress in comparison to those of conventional surfaces.

18.
Front Pharmacol ; 12: 719880, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34483931

RESUMEN

The Wnt/ß-catenin signaling pathway plays important roles in embryonic development and tissue homeostasis. Wnt signaling is induced, and ß-catenin is activated, associated with the development and progression of renal fibrosis. Wnt/ß-catenin controls the expression of various downstream mediators such as snail1, twist, matrix metalloproteinase-7, plasminogen activator inhibitor-1, transient receptor potential canonical 6, and renin-angiotensin system components in epithelial cells, fibroblast, and macrophages. In addition, Wnt/ß-catenin is usually intertwined with other signaling pathways to promote renal interstitial fibrosis. Actually, given the crucial of Wnt/ß-catenin signaling in renal fibrogenesis, blocking this signaling may benefit renal interstitial fibrosis. There are several antagonists of Wnt signaling that negatively control Wnt activation, and these include soluble Fzd-related proteins, the family of Dickkopf 1 proteins, Klotho and Wnt inhibitory factor-1. Furthermore, numerous emerging small-molecule ß-catenin inhibitors cannot be ignored to prevent and treat renal fibrosis. Moreover, we reviewed the knowledge focusing on anti-fibrotic effects of natural products commonly used in kidney disease by inhibiting the Wnt/ß-catenin signaling pathway. Therefore, in this review, we summarize recent advances in the regulation, downstream targets, role, and mechanisms of Wnt/ß-catenin signaling in renal fibrosis pathogenesis. We also discuss the therapeutic potential of targeting this pathway to treat renal fibrosis; this may shed new insights into effective treatment strategies to prevent and treat renal fibrosis.

19.
J Nanosci Nanotechnol ; 10(8): 5379-82, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21125902

RESUMEN

The influence of Cr content and nanograin size on the microstructure, the mechanical and sliding tribological behaviors of Cr-containing diamond-like carbon (Cr-DLC) films, deposited on (100) Si substrate by a mid-frequency dual-magnetron system, was explored. The Cr-containing nanoparticles (combining Cr with C) were dispersed in the amorphous DLC matrix while some nanoparticles were transformed into compounds of C/Cr. The incorporation of Cr into Cr-DLC films improved the crystallinity of the Cr-rich nanoparticles and partially converted the nanoparticles to Cr/C phase. The films with Cr content ranging between 5-10 at% and with Cr-containing nanograin sizes in range of 15-27 nm were found to possess higher hardness, lower intrinsic stress, lower coefficient of friction (COF) and wear rate than those of 16-28 at% Cr content and 46-74 nm nanograin sizes. The superhard Cr-DLC film with 8.3 at% Cr and 18.4 nm Cr-containing grain gave the favorable micro-tribological characteristics with COF at micro approximately 0.1 and wear rate at 3.6 x 10(-8) mm3/Nm.

20.
Molecules ; 15(4): 2551-63, 2010 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-20428063

RESUMEN

To map out the efficient organocatalyst requirements in the Michael addition of 1,3-dicarbonyl indane compounds to nitrostyrenes, a dozen different amino organocatalysts containing a p-toluenesulfonyl group (Ts) have been evaluated; excellent enantio-selectivities (up to er 92:8) were obtained with a primary amine-based Ts-DPEN catalyst and a plausible catalytic reaction mechanism was proposed on the basis of the experimental results.


Asunto(s)
Indanos/química , Estirenos/química , Compuestos de Tosilo/química , Catálisis
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA