Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Zool Res ; 44(4): 678-692, 2023 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-37147886

RESUMEN

The stress response is essential for animal self-defense and survival. However, species may exhibit stress response variation depending on their specific environmental and selection pressures. Blind cavefish dwell in cave environments, which differ markedly in stressors and resource availability compared to surface aquatic environments. However, whether blind cavefish exhibit differences in stress response as an adaptation to their cave environments remains unclear. Here, we investigated differences in stress response in six closely related Triplophysa species, including three blind cavefish (T. longibarbata, T. jiarongensis, and T. rosa) and three normal-sighted river fish (T. nasobarbatula, T. dongsaiensis, and T. bleekeri). Results showed that blind cavefish exhibited a range of distinct behavioral responses compared to sighted river fish, including greater levels of activity, shorter duration of freezing, absence of erratic movements or thrashing behavior, and opposite behavioral trends over time. Furthermore, the cavefish species demonstrated attenuated increases in metabolic rate in response to stressors related to novel environments. Cave-dwelling T. rosa also exhibited lower basal hypothalamic-pituitary-inter-renal (HPI) axis-related gene expression levels and stress hormone concentrations compared to river-dwelling T. bleekeri. These results suggest that blind cavefish may have lost their behavioral stress response, potentially mediated by a reduction in basal activity of the HPI axis, thus enabling the conservation of energy by reducing unnecessary expenditure in energy-limited caves.


Asunto(s)
Characidae , Cipriniformes , Animales , Evolución Biológica , Characidae/fisiología , Adaptación Fisiológica , Cipriniformes/genética , Metabolismo Energético , Cuevas
2.
Br J Radiol ; 95(1134): 20210768, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35262392

RESUMEN

OBJECTIVE: To explore the correlation between radiomic features and the pathology of pure ground-glass opacities (pGGOs), we established a radiomics model for predicting the pathological subtypes of minimally invasive adenocarcinoma (MIA) and precursor lesions. METHODS: CT images of 1521 patients with lung adenocarcinoma or precursor lesions appearing as pGGOs on CT in our hospital (The Third Affiliated Hospital of Sun Yat-sen University) from January 2015 to March 2021 were analyzed retrospectively and selected based on inclusion and exclusion criteria. pGGOs were divided into an atypical adenomatous hyperplasia (AAH)/adenocarcinoma in situ (AIS) group and an MIA group. Radiomic features were extracted from the original and preprocessed images of the region of interest. ANOVA and least absolute shrinkage and selection operator feature selection algorithm were used for feature selection. Logistic regression algorithm was used to construct radiomics prediction model. Receiver operating characteristic curves were used to evaluate the classification efficiency. RESULTS: 129 pGGOs were included. 2107 radiomic features were extracted from each region of interest. 18 radiomic features were eventually selected for model construction. The area under the curve of the radiomics model was 0.884 [95% confidence interval (CI), 0.818-0.949] in the training set and 0.872 (95% CI, 0.756-0.988) in the test set, with a sensitivity of 72.73%, specificity of 88.24% and accuracy of 79.47%. The decision curve indicated that the model had a high net benefit rate. CONCLUSION: The prediction model for pathological subtypes of MIA and precursor lesions in pGGOs demonstrated a high diagnostic accuracy. ADVANCES IN KNOWLEDGE: We focused on lesions appearing as pGGOs on CT and revealed the differences in radiomic features between MIA and precursor lesions. We constructed a radiomics prediction model and improved the diagnostic accuracy for the pathology of MIA and precursor lesions.


Asunto(s)
Adenocarcinoma , Neoplasias Pulmonares , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/patología , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/patología , Invasividad Neoplásica , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos
3.
J Org Chem ; 86(15): 10288-10302, 2021 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-34288680

RESUMEN

2-Aminobenzothiazoles comprise a valuable structural motif, which prevails in versatile natural products and biologically active compounds. Herein, a switchable and scalable C-N coupling protocol was developed for the synthesis of these compounds from 2-chlorobenzothiazoles and primary amines. Gratifyingly, this protocol was achieved under transition-metal-free and solvent-free conditions. Moreover, introducing an appropriate amount of NaH completely switched the selectivity from mono- toward di-heteroarylation, and further investigations provided a rationale for this new finding. Furthermore, gram-scale synthesis of representative products 3a and 4a was realized by applying operationally simple and glovebox-free procedures, which revealed the practical usefulness of this work. Finally, evaluation of the quantitative green metrics provided evidence that our protocol was superior over the literature ones in terms of green chemistry and sustainability.


Asunto(s)
Aminas , Elementos de Transición , Solventes
4.
Eur Radiol ; 30(8): 4427-4433, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32291501

RESUMEN

A serious epidemic of COVID-19 broke out in Wuhan, Hubei Province, China, and spread to other Chinese cities and several countries now. As the majority of patients infected with COVID-19 had chest CT abnormality, chest CT has become an important tool for early diagnosis of COVID-19 and monitoring disease progression. There is growing evidence that children are also susceptible to COVID-19 and have atypical presentations compared with adults. This review is mainly about the differences in clinical symptom spectrum, diagnosis of COVID-19, and CT imaging findings between adults and children, while highlighting the value of radiology in prevention and control of COVID-19 in pediatric patients. KEY POINTS: • Compared with adults, pediatric patients with COVID-19 have the characteristics of lower incidence, slighter clinical symptoms, shorter course of disease, and fewer severe cases. • The chest CT characteristics of COVID-19 in pediatric patients were atypical, with more localized GGO extent, lower GGO attenuation, and relatively rare interlobular septal thickening. • Chest CT should be used with more caution in pediatric patients with COVID-19 to protect this vulnerable population from risking radiation.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/diagnóstico por imagen , Neumonía Viral/diagnóstico por imagen , COVID-19 , Niño , China/epidemiología , Progresión de la Enfermedad , Humanos , Pandemias , SARS-CoV-2 , Tomografía Computarizada por Rayos X
5.
Pest Manag Sci ; 70(3): 462-9, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23765738

RESUMEN

BACKGROUND: A good knowledge in wetting behavior of pesticide spray liquid on plant surface is crucial to spray applications. Difference in leaf surface wettability would result in obvious changes in spray wetting behavior. The aim of this paper is to obtain the changes of wettability during different growth periods. RESULTS: The contact angle (CA) of rice leaf for each liquid increased with rice growth. No significant difference was found between cultivars. The CA was found to be correlated with the polar component of liquid surface tension. The square of the polar component was also found to be highly significant indicating that the relationship between these two properties was not a simple linear one. The surface energy of each plant surface decreased as the plants aged. This was also true of each part of the surface energy. However, no obvious difference on the proportion of the components was found among different cultivars and stages. CONCLUSIONS: The changes in value of CA and surface free energy (SFE) both reflect the changes of the leaf surface wettability, while the SFE value shows better in wettability characterizing. Obvious rice leaf wettability changes were found on different development stages, which may be beneficial for researches in agrochemical sprays wetting and spreading behavior. Factors influencing these alterations were discussed.


Asunto(s)
Oryza/química , Hojas de la Planta/química , Hojas de la Planta/crecimiento & desarrollo , Biofisica/métodos , Oryza/clasificación , Oryza/crecimiento & desarrollo , Hojas de la Planta/clasificación , Propiedades de Superficie , Humectabilidad
6.
Small ; 2(3): 422-7, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17193062

RESUMEN

Single-crystalline hexagonal alpha-Fe(2)O(3) nanorods/nanobelts have been created by a simple iron-water reaction in the low-temperature range of 350-450 degrees C. Scanning electron microscopy examination shows that the needle-like products, radiating from and perpendicular to the original large iron particle surfaces, are up to a few micrometers in length with an average diameter from 20 nm (tip) to 100 nm (base). X-ray photoelectron spectroscopy and FTIR spectroscopy reveal that the outermost surface of the nanorods consists of Fe(2)O(3) without organic impurity contaminants, which could possibly result from other methods, such as hydrothermal growth. Nanobelt-like structures are believed to result from a combination of increased reaction temperature and time. The initial formation and subsequent growth of alpha-Fe(2)O(3) nanorods may be explained by the iron metal corrosion mechanism.


Asunto(s)
Cristalización/métodos , Compuestos Férricos/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Agua/química , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Soluciones , Propiedades de Superficie
8.
J Phys Chem B ; 110(37): 18191-5, 2006 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-16970435

RESUMEN

WO(x) (2 < x < 3) and WS(2) nanostructures have been widely praised due to applications as catalysts, solid lubricants, field emitters, and optical components. Many methods have been developed to fabricate these nanomaterials; however, most attention was focused on the same dimensional transformation from WO(x) nanoparticles or nanorods to WS(2) nanoparticles or nanotubes. In a solid-vapor reaction, by simply controlling the quantity of water vapor and reaction temperature, we have realized the transformation from quasi-zero-dimensional WS(2) nanoparticles to one-dimensional W(18)O(49) nanorods, and subsequent sulfuration reactions have further converted these W(18)O(49) nanorods into WS(2) nanotubes. The reaction temperature, quantity of water vapor, and pretreatment of the WS(2) nanoparticle precursors are important process parameters for long, thin, and homogeneous W(18)O(49) nanorods growth. The morphologies, crystal structures, and circling transformation mechanisms of sulfide-oxide-sulfide are discussed, and the photoluminescence properties of the resulting nanorods are investigated using a Xe lamp under an excitation of 270 nm.

9.
J Am Chem Soc ; 127(46): 16263-72, 2005 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-16287319

RESUMEN

The excellent shock-absorbing performance of WS2 and MoS2 nanoparticles with inorganic fullerene-like structures (IFs) under very high shock wave pressures of 25 GPa is described. The combined techniques of X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, thermal analysis, and transmission electron microscopy have been used to evaluate the diverse, intriguing features of shock recovered IFs, of interest for their tribological applications, thereby allowing improved understanding of their antishock behavior and structure-property relationships. Two possible failure mechanisms are proposed and discussed. The supershock-absorbing ability of the IF-WS2 enables them to survive pressures up to 25 GPa accompanied with concurrent temperatures of up to 1000 degrees C without any significant structural degradation or phase change making them probably the strongest cage molecules now known.

11.
J Am Chem Soc ; 125(5): 1329-33, 2003 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-12553835

RESUMEN

The shock-wave resistance of WS(2) nanotubes has been studied and compared to that of carbon nanotubes. Detailed structural features of post-shock samples were investigated using HRTEM, XRD, and Raman spectroscopy. WS(2) nanotubes are capable of withstanding shear stress caused by shock waves of up to 21 GPa, although some nanotube tips and nanoparticles containing multiple structural defects in the bending regions are destroyed. Small WS(2) species, consisting of only a few layers, are extruded from the nanotubes. Well-crystallized tube bodies were found to exhibit significant stability under shock, indicating high tensile strength. XRD and Raman analyses have confirmed this structural stability. Under similar shock conditions, WS(2) tubes are more stable than carbon nanotubes, the latter being transformed into a diamond phase. WS(2) nanotubes containing small concentrations of defects possess significantly higher mechanical strength, and, as a consequence, hollow WS(2) nanoparticles are expected to act as excellent lubricants under much higher loading than was previously thought.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...