Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Mol Med Rep ; 29(6)2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38577934

RESUMEN

Hepatitis B X­interacting protein (HBXIP) is a membrane protein located on the lysosomal surface and encoded by the Lamtor gene. It is expressed by a wide range of tumor types, including breast cancer, esophageal squamous cell carcinoma and hepatocellular carcinoma, and its expression is associated with certain clinicopathological characteristics. In the past decade, research on the oncogenic mechanisms of HBXIP has increased and the function of HBXIP in normal cells has been gradually elucidated. In the present review, the following was discussed: The normal physiological role of the HBXIP carcinogenic mechanism; the clinical significance of high levels of HBXIP expression in different tumors; HBXIP regulation of transcription, post­transcription and post­translation processes in tumors; the role of HBXIP in improving the antioxidant capacity of tumor cells; the inhibition of ferroptosis of tumor cells and regulating the metabolic reprogramming of tumor cells; and the role of HBXIP in promoting the malignant progression of tumors. In conclusion, the present review summarized the existing knowledge of HBXIP, established its carcinogenic mechanism and discussed future related research on HBXIP.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Proteínas Oncogénicas , Humanos , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Neoplasias Hepáticas/genética , Proteínas Oncogénicas/metabolismo
2.
Nat Sci Sleep ; 16: 401-411, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38680190

RESUMEN

Purpose: Chronic intermittent hypoxia (CIH) related arterial endothelium injury is a common cause of cardiovascular system injury. However, the mechanism still needs to be clarified. In this study, we aimed to clarify the role and mechanism of ferrostatin-1 (Fer-1) in CIH-related rat arterial endothelial cells (ROAEC) ferroptosis. Methods: ROAEC was divided into control group, CIH group, and CIH+ Fer-1 group. Cell viability was detected by cell counting kit 8 kits (CCK8). The apoptotic rate, reactive oxygen species (ROS) levels, Fe2+ levels, and lipid ROS levels were detected by flow cytometry. Malondialdehyde (MDA) levels and nicotinamide adenine dinucleotide (NAD+)/NADH ratio were detected via Elisa kits. The mRNA and protein levels of cystine/glutamate antiporter solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) were detected by qRT-PCR and Western blot. Mitochondrial structure and function were observed by transmission electron microscope (TEM) and mitochondrial membrane potential (MMP). Central carbon metabolism was measured to compare metabolites among each group. Results: After the CIH exposure, ROAEC cell viability decreased; The levels of cell apoptosis, ROS, Fe2+, MDA, and lip ROS increased; The levels of NAD+/NADP ratio decreased; The mRNA and protein levels of GPX4 and SLC7A11 decreased (all p<0.05). Co-cultured with Fer-1 reversed the levels of apoptosis rate, cell viability, ROS, Fe2+, MAD, lipid ROS, NAD+/NADH ratio and the mRNA and protein expression of GPX4 and SLC7A11 (all p<0.05). The TEM results showed that damaged mitochondrial membrane and the matrix spillover in the CIH group. The results of the JC-1 assay showed decreased MMP in the CIH group. Fer-1 treatment ameliorated the mitochondrial injury. The results of central carbon metabolism found that CIH altered the metabolites in the TCA cycle, which were reversed by Fer-1 treatment. Conclusion: CIH-induced ferroptosis in ROAEC, which were reversed by Fer-1 via reprogramming mitochondrial function.

3.
J Exp Psychol Hum Percept Perform ; 49(3): 306-326, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37036672

RESUMEN

Although group members may be diverse and have their own reasons for actions, people tend to generalize the actions of known members to unknown cases from the observer's perspective. Nevertheless, it is unclear whether action generalization is entirely determined by statistical evidence or is additionally constrained by prior knowledge or beliefs toward group members' actions. Given that people specifically believe that group members pursue common action goals, we hypothesized that action generalization is constrained by this belief. Accordingly, the extent of generalizing a goal underlying action does not always increase as the prevalence of the goal increases; instead, a strict monotonicity effect is observed for the action's movement. We found that the common goal is generalized to a new group member only when all sampled group members have this target property, revealing that the relation between the prevalence of goals and the strength of their generalization violates strict monotonicity (Studies 1a and 1b). In contrast, the more group members perform the same movement, the more likely this movement is to be generalized to an unknown group member, showing monotonic generalization of movements (Studies 3a, 3b, and 3c). Importantly, these dissociative generalizations are specific to entitative social groups (Studies 2, 4, and 6) and not due to differences in experimental tasks between studies. In shared experimental paradigms, when the goal status is available, the monotonic generalization of actions is not found; however, when the goal status is unavailable and the movement is still accessed, the monotonic generalization of actions is observed (Study 5). Thus, our findings highlight that the belief that group members pursue a common goal constrains action generalization to a greater extent than statistical evidence. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Asunto(s)
Generalización Psicológica , Movimiento , Humanos , Prevalencia , Objetivos
4.
Inorg Chem ; 62(12): 5032-5039, 2023 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-36919994

RESUMEN

Developing efficient atomic-scale metal-supported catalysts is of great significance for energy conversion technologies. However, the precise modulation of electron transfer between the metal and supporter in atomic-scale metal-supported catalysts to further improve the catalytic activity is still a major challenge. Herein, we show tunable electron transfer between atomic-scale Pt and tungsten nitride/oxide supports (namely, Pt/WN and Pt/W18O49). Pt/WN with modest electron exchange and Pt/W18O49 with aggressive electron exchange exhibit notably different catalytic activities for the alkaline hydrogen oxidation reaction (HOR), in which Pt/WN shows a 5.7-fold enhancement in HOR intrinsic catalytic performance in comparison to Pt/W18O49. Additionally, the tunable electronic transfer at the interface of Pt/WN and Pt/W18O49, as proven by the theoretical calculation, resulted in the discrepancy of the adsorption free energy of the reaction intermediates, as well as catalytic activity, for the HOR process. Our work provides new insights into the design of advanced atomic-scale metal-supported catalysts for electrocatalysis.

5.
Int J Clin Pract ; 2023: 9310588, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36694611

RESUMEN

Background: Older age is a risk factor for obstructive sleep apnea (OSA), which is associated with the development of nonalcoholic fatty liver disease (NAFLD). We aimed to investigate the correlation between OSA and liver injury among older patients. Study Design. This is a cross-sectional study. Methods: Consecutive older (≥60 years) snoring patients were included. Subjects were divided into no OSA, mild OSA, moderate OSA, and severe OSA groups according to the apnea-hypopnea index (AHI) and were also separated into liver injury and nonliver injury groups based on liver function. Logistic regression analysis was applied to analyze the independent risk factors for liver injury. Results: We studied 227 patients (155 male, 72 female). The prevalence of liver injury exhibited an increasing trend among groups with mild-to-severe OSA. In addition, body mass index, AHI, and TG showed significant differences between the liver injury and nonliver injury groups. Logistic regression analysis revealed that AHI and TG were the major contributing factors for liver injury in older patients (adjusted odds ratio [OR] = 1.055, p=0.013, and OR = 1.485, p=0.039, respectively). Conclusions: Older patients with OSA have an increased risk of liver injury and NAFLD, and sleep apnea and high TG are important factors in contributing to the development of liver injury.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Apnea Obstructiva del Sueño , Humanos , Masculino , Femenino , Anciano , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Estudios Transversales , Apnea Obstructiva del Sueño/complicaciones , Apnea Obstructiva del Sueño/epidemiología , Factores de Riesgo
6.
Biomedicines ; 11(1)2023 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-36672701

RESUMEN

The incidence of Alzheimer's disease (AD) is increasing year by year, which brings great challenges to human health. However, the pathogenesis of AD is still unclear, and it lacks early diagnostic targets. The entorhinal cortex (EC) is a key brain region for the occurrence of AD neurodegeneration, and neuroinflammation plays a significant role in EC degeneration in AD. This study aimed to reveal the close relationship between inflammation-related genes in the EC and AD by detecting key differentially expressed genes (DEGs) via gene function enrichment pathway analysis. GSE4757 and GSE21779 gene expression profiles of AD were downloaded from the Gene Expression Omnibus (GEO) database. R language was used for the standardization and differential analysis of DEGs. Then, significantly enriched Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed to predict the potential biological functions of the DEGs. Finally, the significant expressions of identified DEGs were verified, and the therapeutic values were detected by a receiver operating characteristic (ROC) curve. The results showed that eight up-regulated genes (SLC22A2, ITGB2-AS1, NIT1, FGF14-AS2, SEMA3E, PYCARD, PRORY, ADIRF) and two down-regulated genes (AKAIN1, TRMT2B) may have a potential diagnostic value for AD, and participate in inflammatory pathways. The area under curve (AUC) results of the ten genes showed that they had potential diagnostic value for AD. The AUC of PYCARD was 0.95, which had the most significant diagnostic value, and it is involved in inflammatory processes such as the inflammasome complex adaptor protein. The DEGs screened, and subsequent pathway analysis revealed a close relationship between inflammation-related PYCARD and AD, thus providing a new basis for an early diagnostic target for AD.

7.
Sleep Breath ; 27(4): 1465-1471, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-36474109

RESUMEN

OBJECTIVE: We aimed to examine the influence of sleep disturbances on the risk of oligo/astheno/teratozoospermia (OAT) in men attending an infertility clinic. METHODS: We consecutively enrolled men attending an infertility clinic from July 2020 to June 2021. Semen parameters were obtained at initial presentation, and the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale score, and the STOP-BANG Questionnair were completed to assess sleep quality. Embryo outcomes were evaluated after infertility treatment. RESULTS: Of 466 men enrolled, 119 had OAT (OAT group) and 347 had normozoospermia (NS group). There were no differences between the two groups regarding Epworth Sleepiness Scale and STOP-BANG Questionnaire scores. The prevalence of poor sleep quality (Pittsburgh Sleep Quality Index score ≥ 5) in the OAT group was significantly higher than that in the NS group (42% vs. 29%, p = 0.009). A higher rate of poor subjective sleep quality was observed in the OAT group compared with the NS group (p = 0.005) and Pearson's correlations revealed a negative relationship between subjective sleep quality and semen quality. Logistic regression found that subjective sleep quality was independently associated with an increased risk of OAT (adjusted odds ratio = 0.610, p = 0.007). CONCLUSIONS: Men with OAT attending an infertility clinic exhibited poor subjective sleep quality. Improving sleep disturbances may be a target intervention to reduce the risk of OAT. This possibility warrants further investigation.


Asunto(s)
Trastornos del Inicio y del Mantenimiento del Sueño , Trastornos del Sueño-Vigilia , Teratozoospermia , Masculino , Humanos , Autoinforme , Estudios Longitudinales , Calidad del Sueño , Análisis de Semen , Clínicas de Fertilidad , Somnolencia , Trastornos del Sueño-Vigilia/diagnóstico , Trastornos del Sueño-Vigilia/epidemiología
8.
Sleep Breath ; 27(3): 1005-1011, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-35951213

RESUMEN

PURPOSE: Obstructive sleep apnea (OSA) is related to increased risk of cardiovascular disease. Ferroptosis is a form of programmed cell death characterized by iron overload and plays critical roles in myocardial injury. This study aimed to investigate the role of ferroptosis in intermittent hypoxia (IH)-induced myocardial injury involving endoplasmic reticulum stress (ERS). METHODS: AC16 human cardiomyocytes were exposed to IH or normoxia conditions. Mice were randomly grouped as follows: normal control (NC), IH, ferrostatin-1 + IH (FIH), and N-acetylcysteine + IH (AIH). The mRNA levels of GPX4, xCT, FTH1, and FACL4 in AC16 cells were detected by qRT-PCR. The protein levels of GPX4, xCT, NOX4, ATF4, CHOP, Bcl-2, and Bax in myocardial tissue were detected by Western blot analysis. RESULTS: The mRNA expression levels of GPX4 and xCT in AC16 cells were significantly lower in IH group than that of NC group. In IH mice, myocardial tissues were injured accompanied by increased level of ferroptosis and ERS. Inhibition of ferroptosis and treatment of N-acetylcysteine reduced ERS and myocardial injury in mice exposed to IH. In addition, compared to ferrostatin-1, N-acetylcysteine exerted a greater effect in relieving IH-induced myocardial damage and ERS. CONCLUSIONS: Ferroptosis was involved in IH-related myocardial injury accompanied by the activation of ERS. Inhibition of ferroptosis and acetylcysteine treatment alleviated IH-related myocardial injury, which may be a potential target for therapeutic approaches to OSA-induced myocardial injury.


Asunto(s)
Ferroptosis , Apnea Obstructiva del Sueño , Humanos , Ratones , Animales , Acetilcisteína/farmacología , Hipoxia , Estrés del Retículo Endoplásmico , Apnea Obstructiva del Sueño/complicaciones
9.
BMC Pulm Med ; 22(1): 488, 2022 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-36572881

RESUMEN

PURPOSE: Chronic intermittent hypoxia (CIH) causes lung injury but the mechanism is unclear. Ferroptosis is a novel form of programmed cell death. In this research, we attempted to explore the role of ferroptosis in CIH-induced lung injury both in vitro and in vivo. METHODS: Sprague-Dawley rats were randomly separated into control group, CIH group and CIH + ferrostatin-1 group (CIH + Fer-1). Rats in the CIH group and CIH + Fer-1 group were exposed to intermittent hypoxia for 12 weeks. Human bronchial epithelial cell line (BEAS-2B) was cultivated for 24 h in either conventional culture medium or under CIH conditions. Fer-1 was applied to observe its treatment effects. Histological changes were evaluated by Hematoxylin-eosin (HE) staining and masson staining. The expression levels of Acyl-CoA synthetase long-chain family member 4 (ACSL4), glutathione peroxidase 4 (GPX4), interleukin-6 (IL-6) and tumour necrosis factor α (TNFα) were detected via qRT-PCR or Western blot. Cell counting kit-8 (CCK-8) was used to assess cell viability. The apoptotic rate and reactive oxygen species (ROS) was calculated by flow cytometry. RESULTS: Histology showed that CIH treatment induced lung injury and pulmonary fibrosis in lung tissue. After Fer-1 treatment, the pathological changes caused by CIH alleviated. The mRNA and protein levels of GPX4 decreased significantly in lung tissues of CIH-treated rats and BEAS-2B, (p < 0.05). The mRNA and protein levels of ACSL4 increased significantly in lung tissues of CIH-treated rats and BEAS-2B, (p < 0.05). The mRNA levels of IL-6 and TNFα in BEAS-2B increased after CIH treatment, (p < 0.05). Cell viability decreased, apoptosis rate and ROS increased in CIH-treated BEAS-2B, (p < 0.05). Cotreatment with Fer-1 reversed CIH-induced apoptosis, cell viability, ROS accumulation, mRNA and protein levels of GPX4, ACSL4, IL-6 and TNFα both in vitro and in vivo (p < 0.05). CONCLUSIONS: Ferroptosis occurred in CIH-induced lung injury, both in vitro and in vivo. The ferroptosis inhibitor Fer-1 alleviated cell injury and ferroptosis in CIH-treated BEAS-2B and lung tissues of rats.


Asunto(s)
Ferroptosis , Lesión Pulmonar , Ratas , Humanos , Animales , Lesión Pulmonar/etiología , Factor de Necrosis Tumoral alfa , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno , Interleucina-6 , Hipoxia/metabolismo , ARN Mensajero
10.
J Am Chem Soc ; 144(25): 11138-11147, 2022 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-35674660

RESUMEN

Developing efficient hydrogen oxidation reaction (HOR) electrocatalysts in alkaline media is of great significance for anion exchange membrane fuel cells. Herein, we report the synthesis of hollow colloidosomes composed of Ru nanocrystals based on a novel gas/liquid interface self-assembly strategy. Structural characterizations reveal that much defects are present in the building block (Ru nanocrystals) of Ru colloidosomes. Theoretical calculations suggest that the defects in the Ru structure can optimize the adsorption binding energy of reaction intermediates for the HOR. Benefiting from the assembled colloidosome and optimized electronic structure, the Ru colloidosomes exhibit remarkable HOR catalytic performance in alkaline media with a mass activity higher than that of benchmark Pt/C. Our work may shed new light on the rational design of advanced electrocatalysts with an assembled structure for energy-related applications.

11.
Comput Methods Biomech Biomed Engin ; 25(7): 740-749, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34792427

RESUMEN

Stent retriever thrombectomy has become an effective method for treating acute ischemic stroke. Successful recanalization cannot be achieved for all patients. The outcome of mechanical thrombectomy may be associated with some mechanical factors, requiring efficient tools that are able to assess the interaction between stent retrievers and clots. In this study, a simulation by finite element analysis was developed to evaluate the outcome of stent retriever thrombectomy for clots of different sizes and frictional properties. The deployment and retrieval of the stent retriever were conducted in a middle cerebral artery model. The recanalization, deformation of the clot and stent retriever and the stress induced in the clot were assessed. The results showed that higher friction could lead to failed recanalization and increased stress in the clot. The simulation method can be used to characterize the mechanical behaviour of stent retrievers and clots, offering a potential tool for the optimization of device design and the selection of surgical strategies.


Asunto(s)
Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Análisis de Elementos Finitos , Humanos , Estudios Retrospectivos , Stents , Accidente Cerebrovascular/cirugía , Trombectomía/efectos adversos , Trombectomía/métodos , Resultado del Tratamiento
12.
Angew Chem Int Ed Engl ; 60(39): 21575-21582, 2021 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-34355481

RESUMEN

The introduction of heteroatoms is one of the most important ways to modulate the intrinsic electronic structure of electrocatalysts to improve their catalytic activity. However, for transition metal chalcogenides with highly symmetric crystal structure (HS-TMC), the introduction of heteroatoms, especially those with large atomic radius, often induces large lattice distortion and vacancy defects, which may lead to structural phase transition of doped materials or structural phase reconstruction during the catalytic reaction. Such unpredictable situations will make it difficult to explore the connection between the intrinsic electronic structure of doped catalysts and catalytic activity. Herein, taking thermodynamically stable cubic CoSe2 phase as an example, we demonstrate that nitrogen incorporation can effectively regulate the intrinsic electronic structure of HS-TMC with structural phase stability and thus promote its electrocatalytic activity for the hydrogen evolution activity (HER). In contrast, the introduction of phosphorus can lead to structural phase transition from cubic CoSe2 to orthorhombic phase, and the structural phase of phosphorus-doped CoSe2 is unstable for HER.

13.
Acta Psychol (Amst) ; 202: 102948, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31751830

RESUMEN

Though distance perception feeds the fundamental input that constructs a visual structure of the world, the suggestion has been made that it is constrained by this constructed structure. Instead of focusing on the physically defined structure, this study investigates whether and how social relations, especially the quality of social interaction (how individuals interact) rather than its content (what type of social interaction), precisely influences distance perception. The quality of social interaction was framed as an actor's intent and incurred outcome regarding another individual, whether helpful or harmful. Through visual animations, intent was operationalized as an agent's (i.e., actor's) intentional or unintentional act having an influence on another agent (i.e., affectee). Two experiments were conducted. In Experiment 1, the act was helpful, resulting in small or great beneficial consequences to the affectee. In Experiment 2, the act was harmful and resulted in small or great losses to the affectee. We found that when the help or harm had a large effect on others (the great-benefits or great-losses conditions), distance was perceived as shorter than when help or harm was minor, and the actor's intent did not affect distance perception. This suggests that, regardless of the type of social interaction, distance perception is mainly influenced by the outcome of an act not by the actor's intent. It implies that the perceived quality of social interaction creates a social constraint on distance perception. These findings are consistent with the idea that the intent and outcome of an action are assessed differently, and they help us understand how social relation penetrates the perceptual system.


Asunto(s)
Percepción de Distancia/fisiología , Intención , Relaciones Interpersonales , Estimulación Luminosa/métodos , Percepción Social , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven
14.
Front Psychol ; 10: 2557, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31824373

RESUMEN

Previous studies have indicated that social evaluations rely heavily on the outcome of an actor's behavior toward a recipient. These studies focused on interactions in which two agents are connected by an external goal (i.e., object-mediated social interaction) and revealed that the intent behind an action has a privileged role in evaluating the valence of a social interaction. The current study investigated whether the intent behind an action influences evaluation of contingent social interactions wherein one agent responds to another without referring to a specific target. To clarify this, we operationalized intent as harmful or harmless when one agent hit another (i.e., recipient), and manipulated the action's outcome by determining to what extent it changed the recipient's state (i.e., falling down or moving slightly). Results showed that in contingent interactions with both direct launching (i.e., the actor directly caused the change) and extended launching (i.e., the actor caused the change through a mediated block), when the action significantly affected the recipient, the agents were evaluated as having a more negative social interaction than when the influence was small; this effect was independent of the intent behind the action. Such findings demonstrated that evaluations of contingent social interactions are primarily influenced by an actor's causal role in the outcome, not the intent behind an action. This null effect of intent when evaluating social interaction contrasts with findings on object-mediated social interaction, which is consistent with human social evaluations relying on two dissociable systems: causal and intentional components.

15.
Phys Rev E ; 97(6-1): 062409, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30011464

RESUMEN

The Helfrich bending energy plays an important role in providing a mechanism for the conformation of a lipid vesicle in theoretical biophysics, which is governed by the principle of energy minimization over configurations of appropriate topological characteristics. We will show that the presence of a quantity called the spontaneous curvature obstructs the existence of a minimizer of the Helfrich energy over the set of embedded ring tori. In addition, despite the well-realized knowledge that lipid vesicles may present themselves in a variety of shapes of complicated topology, there is a lack of topological bounds for the Helfrich energy. To overcome these difficulties, we consider a general scale-invariant anisotropic curvature energy that extends the Canham elastic bending energy developed in modeling a biconcave-shaped red blood cell. We will show that, up to a rescaling of the generating radii, there is a unique minimizer of the energy over the set of embedded ring tori, in the entire parameter regime, which recovers the Willmore minimizer in its Canham isotropic limit. We also show how elevated anisotropy favors energetically a clear transition from spherical-, to ellipsoidal-, and then to biconcave-shaped surfaces, for a lipid vesicle. We then establish some genus-dependent topological lower and upper bounds for the anisotropic energy. Finally, we derive the shape equation of the generalized bending energy, which extends the well-known Helfrich shape equation.


Asunto(s)
Lípidos , Membranas Artificiales , Modelos Biológicos , Animales , Anisotropía , Fenómenos Biomecánicos , Elasticidad , Eritrocitos/citología , Eritrocitos/fisiología , Lípidos/química , Propiedades de Superficie
16.
Proc Math Phys Eng Sci ; 471(2176): 20140970, 2015 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-27547084

RESUMEN

Recent work of Harland shows that the SO(3)-symmetric, dimensionally reduced, charge-N self-dual Yang-Mills calorons on the hyperbolic space [Formula: see text] may be obtained through constructing N-vortex solutions of an Abelian Higgs model as in the study of Witten on multiple instantons. In this paper, we establish the existence of such minimal action charge-N calorons by constructing arbitrarily prescribed N-vortex solutions of the Witten type equations.

17.
J Zhejiang Univ Sci ; 5(10): 1191-8, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15362189

RESUMEN

Naturally occurring plants in agroecosystem evidently play an important role in ecosystem stability. Field studies on the ecological effects of native plants conserved in orchard and their resistance to adverse climatic stress, and soil erosion were conducted from 1998 to 2001 in a newly developed Changshan-huyou (Citrus changshan-huyou Y.B. Chang) orchard. The experimental area covered 150 ha in typical red soil hilly region in southeastern China. The experimental design was a randomized complete block with six combinations of twelve plant species with four replications. All species used were native in the orchard. Plots were 15 x 8 m2 and separated by 2 m buffer strips. Precipitation, soil erosion in rainstorm days and aboveground biomass of plant community when rainstorm days ended, soil temperature and moisture under various plant covers during seasonal megathermal drought period, antiscourability of soil with different root density under various simulated rainfalls were measured. Plant cover significantly decreased the daily highest and mean soil temperature and its daily variation in hot-drought season, but there was no significant difference of the alleviation among various plant covers. Plant covers significantly increased the soil moisture in seasonal megathermal drought period. Better moisture maintenance and soil erosion reduction was found when the plant species numbers in cover plant communities increased from one to eight. Higher root density in plant communities with higher species richness increased significantly the antiscourability of the soil. It was suggested that conserving plant communities with diversified native species could produce the best positive ecological effects on citrus orchard ecosystem stability.


Asunto(s)
Agricultura/métodos , Citrus/clasificación , Citrus/crecimiento & desarrollo , Ecosistema , Enfermedades de las Plantas , Dinámica Poblacional , Suelo/análisis , Biomasa , Conservación de los Recursos Naturales , Especificidad de la Especie , Clima Tropical
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...