Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Nano Lett ; 24(43): 13702-13707, 2024 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-39423316

RESUMEN

The advent of diffraction limited sources and developments in detector technology opens up new possibilities for the study of materials in situ and operando. Coherent X-ray diffraction techniques such as coherent X-ray diffractive imaging (CXDI) and X-ray photon correlation spectroscopy (XPCS) are capable for this purpose and provide complementary information, although due to signal-to-noise requirements, their simultaneous demonstration has been limited. Here, we demonstrate a strategy for the simultaneous use of CXDI and XPCS to study in situ the Brownian motion of colloidal gold nanoparticles of 200 nm diameter suspended in a glycerol-water mixture. We visualize the process of agglomeration, examine the spatiotemporal space accessible with the combination of techniques, and demonstrate CXDI with 22 ms temporal resolution.

2.
Behav Sci Law ; 42(2): 79-95, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38291970

RESUMEN

Eyewitness testimony serves as important evidence in the legal system. Eyewitnesses of a crime can be either the victims themselves-for whom the experience is highly self-referential-or can be bystanders who witness and thus encode the crime in relation to others. There is a gap in past research investigating whether processing information in relation to oneself versus others would later impact people's suggestibility to misleading information. In two experiments (Ns = 68 and 122) with Dutch and Chinese samples, we assessed whether self-reference of a crime event (i.e., victim vs. bystander) affected their susceptibility to false memory creation. Using a misinformation procedure, we photoshopped half of the participants' photographs into a crime slideshow so that they saw themselves as victims of a nonviolent crime, while others watched the slideshow as mock bystander witnesses. In both experiments, participants displayed a self-enhanced suggestibility effect: Participants who viewed themselves as victims created more false memories after receiving misinformation than those who witnessed the same crime as bystanders. These findings suggest that self-reference might constitute a hitherto new risk factor in the formation of false memories when evaluating eyewitness memory reports.


Asunto(s)
Memoria , Recuerdo Mental , Humanos , Comunicación , Crimen
3.
Proc Natl Acad Sci U S A ; 117(27): 15437-15442, 2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32571925

RESUMEN

Ice amorphization, low- to high-density amorphous (LDA-HDA) transition, as well as (re)crystallization in ice, under compression have been studied extensively due to their fundamental importance in materials science and polyamorphism. However, the nature of the multiple-step "reverse" transformation from metastable high-pressure ice to the stable crystalline form under reduced pressure is not well understood. Here, we characterize the rate and temperature dependence of the structural evolution from ice VII to ice I recovered at low pressure (∼5 mTorr) using in situ time-resolved X-ray diffraction. Unlike previously reported ice VII (or ice VIII)→LDA→ice I transitions, we reveal three temperature-dependent successive transformations: conversion of ice VII into HDA, followed by HDA-to-LDA transition, and then crystallization of LDA into ice I. Significantly, the temperature-dependent characteristic times indicate distinctive thermal activation mechanisms above and below 110-115 K for both ice VIII-to-HDA and HDA-to-LDA transitions. Large-scale molecular-dynamics calculations show that the structural evolution from HDA to LDA is continuous and involves substantial movements of the water molecules at the nanoscale. The results provide a perspective on the interrelationship of polyamorphism and unravel its underpinning complexities in shaping ice-transition kinetic pathways.

4.
Phys Rev Lett ; 125(15): 155702, 2020 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-33095607

RESUMEN

High-pressure metallic ß-Sn silicon (Si-II), depending on temperature, decompression rate, stress, etc., may transform to diverse metastable forms with promising semiconducting properties under decompression. However, the underlying mechanisms governing the different transformation paths are not well understood. Here, two distinctive pathways, viz., a thermally activated crystal-crystal transition and a mechanically driven amorphization, were characterized under rapid decompression of Si-II at various temperatures using in situ time-resolved x-ray diffraction. Under slow decompression, Si-II transforms to a crystalline bc8/r8 phase in the pressure range of 4.3-9.2 GPa through a thermally activated process where the overdepressurization and the onset transition strain are strongly dependent on decompression rate and temperature. In comparison, Si-II collapses structurally to an amorphous form at around 4.3 GPa when the volume expansion approaches a critical strain via rapid decompression beyond a threshold rate. The occurrence of the critical strain indicates a limit of the structural metastability of Si-II, which separates the thermally activated and mechanically driven transition processes. The results show the coupled effect of decompression rate, activation barrier, and thermal energy on the adopted transformation paths, providing atomistic insight into the competition between equilibrium and nonequilibrium pathways and the resulting metastable phases.

5.
Zhongguo Yi Liao Qi Xie Za Zhi ; 41(2): 92-95, 2017 Mar 30.
Artículo en Zh | MEDLINE | ID: mdl-29862676

RESUMEN

Quantitative evaluation on the level of hemiparesis for post-stroke patients is still challenging. In this study, we proposed an innovative method for investigating in vivo muscle behavior in hemiparetic gait. A wearable data collection platform was developed for the simultaneous acquisition of ultrasonography (US), electromyography (EMG) and joint angle during gait cycles. Using this platform, we studied twelve hemiparetic patients during walking on a treadmill and analyzed the corresponding characteristics of their medial gastrocnemius (GM) muscle. Several interesting outputs are achieved such as the observation that dynamic ranges of the both the pennation angle (PA) of GM and EMG signal from same side were more diffused, for the affected side than for the unaffected side. The results suggested that the proposed multimodal signal acquisition and wearable platform is capable of providing comprehensive in vivo information regarding dynamics of ankle and medial gastrocnemius. The proposed platform could be a promising tool for the assessment of hemiparesis patients.


Asunto(s)
Marcha , Accidente Cerebrovascular/complicaciones , Ultrasonografía , Electromiografía , Humanos , Músculo Esquelético , Caminata
6.
BMJ Open ; 14(8): e082851, 2024 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-39187278

RESUMEN

OBJECTIVE: To explore whether sedentary behaviour could modulate the association between overweight or obesity and chronic low back pain (CLBP). DESIGN: A retrospective cross-sectional study. SETTING AND PARTICIPANTS: A total of 4289 participants in the US cohort from the National Health and Nutrition Examination Survey were included. PRIMARY AND SECONDARY OUTCOME MEASURES: CLBP was the outcome. RESULTS: After adjusting for confounding factors, an increased risk of CLBP was identified in people who were overweight (OR 1.41, 95% CI 1.13 to 1.76) and obesity (OR 1.48, 95% CI 1.01 to 2.18). No significant association between sedentary behaviour time and CLBP was observed. In body mass index (BMI)<25 kg/m2 vs BMI≥30 kg/m2 group, sedentary behaviour time showed a modulatory effect on obesity and CLBP (p=0.047). In the sedentary behaviour time >4.5 hours group, the risk of CLBP was increased as BMI elevation, indicating sedentary behaviour time >4.5 hours played a modulatory role in the relationship between obesity and CLBP. CONCLUSION: Obesity was significantly associated with an increased risk of CLBP, and sedentary behaviour time modulated the association between obesity and CLBP. The findings might provide a reference for the lifestyle modifications among individuals with obesity and reducing sedentary behaviour is recommended for this population.


Asunto(s)
Índice de Masa Corporal , Dolor de la Región Lumbar , Encuestas Nutricionales , Obesidad , Conducta Sedentaria , Humanos , Estudios Transversales , Dolor de la Región Lumbar/epidemiología , Obesidad/epidemiología , Obesidad/complicaciones , Masculino , Femenino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto , Estados Unidos/epidemiología , Dolor Crónico/epidemiología , Factores de Riesgo , Sobrepeso/epidemiología , Anciano
7.
BMC Sports Sci Med Rehabil ; 16(1): 96, 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38671510

RESUMEN

OBJECTIVE: This study synthesizes evidence from the Loughborough Passing Test to evaluate the short-passing ability of soccer players and summarizes the reported variables that affect this ability to provide support for the development and improvement of short-passing abilities in soccer players. METHODS: In this systematic review using the PRISMA guidelines, a comprehensive search was conducted in Web of Science, PubMed, and EBSCOhost from inception to July 2023 to identify relevant articles from the accessible literature. Only studies that used the Loughborough test to assess athletes' short-passing ability were included. The quality of the included studies was independently assessed by two reviewers using the PEDro scale, and two authors independently completed the data extraction. RESULTS: Based on the type of intervention or influencing factor, ten studies investigated training, nine studies investigated fatigue, nine studies investigated supplement intake, and five studies investigated other factors. CONCLUSION: Evidence indicates that fitness training, small-sided games training, and warm-up training have positive effects on athletes' short-passing ability, high-intensity special-position training and water intake have no discernible impact, mental and muscular exhaustion have a significantly negative effect, and the effect of nutritional ergogenic aid intake is not yet clear. Future research should examine more elements that can affect soccer players' short-passing ability. TRIAL REGISTRATION: https://inplasy.com/ ., identifier: INPLASY20237.

8.
Front Immunol ; 15: 1423784, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39238645

RESUMEN

Diabetic nephropathy, a common and severe complication of diabetes, is the leading cause of end-stage renal disease, ultimately leading to renal failure and significantly affecting the prognosis and lives of diabetics worldwide. However, the complexity of its developmental mechanisms makes treating diabetic nephropathy a challenging task, necessitating the search for improved therapeutic targets. Intercellular communication underlies the direct and indirect influence and interaction among various cells within a tissue. Recently, studies have shown that beyond traditional communication methods, tunnel nanotubes, exosomes, filopodial tip vesicles, and the fibrogenic niche can influence pathophysiological changes in diabetic nephropathy by disrupting intercellular communication. Therefore, this paper aims to review the varied roles of intercellular communication in diabetic nephropathy, focusing on recent advances in this area.


Asunto(s)
Comunicación Celular , Nefropatías Diabéticas , Exosomas , Nefropatías Diabéticas/patología , Nefropatías Diabéticas/metabolismo , Humanos , Animales , Exosomas/metabolismo
9.
Front Public Health ; 11: 1308375, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38155893

RESUMEN

High blood pressure is the world's leading risk factor for mortality, affecting nearly half of the global population aged 50-79 years. Physical inactivity is one factor contributing to the prevalence of hypertension. This paper discusses a new concept for the management of hypertension in older persons. We are inclined to fade the current guidelines used in China, the United States, and Europe. Although demonstrating irrefutable benefits for blood pressure regulation, the guidelines fail to address the need to incorporate balance exercises, which are crucial for mitigating the risk of falling. We address three pressing questions regarding the efficacy of various combinations of exercise modes for blood pressure regulation, alongside providing an overview of balance exercises. At the core of our concept, we explicate the challenges inherent in addressing the global pandemic of physical inactivity and hypertension in regular socioeconomic people. No guidelines could change the state of inactivity by jumping between zero and all things, where "zero" symbolizes conditions such as physical inactivity and hypertension, and the concept of "all things" encompasses the ideals of an active lifestyle and healthy aging. We advocate a Taoist way, "zero-one-all things," where "one" in this context refers to an inclusive and culturally diverse exercise training cocktail. The Tao guides us to illuminate an ancient way of overcoming physical inactivity-associated diseases in the present day.


Asunto(s)
Ejercicio Físico , Hipertensión , Humanos , Anciano , Anciano de 80 o más Años , Ejercicio Físico/fisiología , Hipertensión/terapia , Presión Sanguínea/fisiología , Terapia por Ejercicio , Hipertensión Esencial
10.
J Hazard Mater ; 459: 132013, 2023 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-37467604

RESUMEN

Deoxynivalenol (DON) is one of the most plentiful trichothecenes occurring in food and feed, which brings severe health hazards to both animals and humans. This study aims to investigate whether sodium butyrate (NaB) can protect the porcine intestinal barrier from DON exposure through promoting mitochondrial homeostasis. In a 4-week feeding experiment, 28 male piglets were allocated according to a 2 by 2 factorial arrangement of treatments with the main factors including supplementation of DON (< 0.8 vs. 4.0 mg/kg) and NaB (0.0 vs. 2 g/kg) in a corn/soybean-based diet. Dietary NaB supplementation mitigated the damaged mitochondrial morphology within the jejunal mucosa and the disrupted gut epithelial tight junctions irritated by DON. In IPEC-J2 cells, we found efficient recovery of the intestinal epithelial barrier occurred following NaB administration. This intestinal barrier reparation was facilitated by NaB-induced PCK2-mediated glyceroneogenesis and restoration of mitochondrial structure and function. In conclusion, we elucidated a mechanism of PCK2-mediated improvement of mitochondrial function by NaB to repair porcine intestinal barrier disruption during chronic DON exposure. Our findings highlight the promise of NaB for use in protecting against DON-induced gut epithelial tight junction disruption in piglets.


Asunto(s)
Tricotecenos , Humanos , Porcinos , Animales , Masculino , Ácido Butírico/farmacología , Ácido Butírico/metabolismo , Tricotecenos/toxicidad , Mucosa Intestinal/metabolismo , Mitocondrias , Fosfoenolpiruvato Carboxiquinasa (ATP)/metabolismo
11.
Sci Rep ; 13(1): 17573, 2023 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-37845245

RESUMEN

The structures, strain fields, and defect distributions in solid materials underlie the mechanical and physical properties across numerous applications. Many modern microstructural microscopy tools characterize crystal grains, domains and defects required to map lattice distortions or deformation, but are limited to studies of the (near) surface. Generally speaking, such tools cannot probe the structural dynamics in a way that is representative of bulk behavior. Synchrotron X-ray diffraction based imaging has long mapped the deeply embedded structural elements, and with enhanced resolution, dark field X-ray microscopy (DFXM) can now map those features with the requisite nm-resolution. However, these techniques still suffer from the required integration times due to limitations from the source and optics. This work extends DFXM to X-ray free electron lasers, showing how the [Formula: see text] photons per pulse available at these sources offer structural characterization down to 100 fs resolution (orders of magnitude faster than current synchrotron images). We introduce the XFEL DFXM setup with simultaneous bright field microscopy to probe density changes within the same volume. This work presents a comprehensive guide to the multi-modal ultrafast high-resolution X-ray microscope that we constructed and tested at two XFELs, and shows initial data demonstrating two timing strategies to study associated reversible or irreversible lattice dynamics.

12.
Materials (Basel) ; 15(11)2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35683147

RESUMEN

Understanding the relationships between the local structures and physical properties of low-dimensional ferroelectrics is of both fundamental and practical importance. Here, pressure-induced enhancement in the photocurrent of SbSI is observed by using pressure to regulate the lone-pair electrons (LPEs). The reconfiguration of LPEs under pressure leads to the inversion symmetry broken in the crystal structure and an optimum bandgap according to the Shockley-Queisser limit. The increased polarization caused by the stereochemical expression of LPEs results in a significantly enhanced photocurrent at 14 GPa. Our research enriches the foundational understanding of structure-property relationships by regulating the stereochemical role of LPEs and offers a distinctive approach to the design of ferroelectric-photovoltaic materials.

13.
Sci Adv ; 8(19): eabl8834, 2022 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-35559678

RESUMEN

Boundaries in animal genomes delimit contact domains with enhanced internal contact frequencies and have debated functions in limiting regulatory cross-talk between domains and guiding enhancers to target promoters. Most mammalian boundaries form by stalling of chromosomal loop-extruding cohesin by CTCF, but most Drosophila boundaries form CTCF independently. However, how CTCF-independent boundaries form and function remains largely unexplored. Here, we assess genome folding and developmental gene expression in fly embryos lacking the ubiquitous boundary-associated factor Cp190. We find that sequence-specific DNA binding proteins such as CTCF and Su(Hw) directly interact with and recruit Cp190 to form most promoter-distal boundaries. Cp190 is essential for early development and prevents regulatory cross-talk between specific gene loci that pattern the embryo. Cp190 was, in contrast, dispensable for long-range enhancer-promoter communication at tested loci. Cp190 is thus currently the major player in fly boundary formation and function, revealing that diverse mechanisms evolved to partition genomes into independent regulatory domains.

14.
J Med Food ; 24(8): 825-832, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34406878

RESUMEN

Schisandra chinensis (S. chinensis) is one of the core drugs used for relieving cough and asthma in traditional Chinese medicine. However, there are few basic studies on the treatment of respiratory diseases with S. chinensis in modern pharmacology, and the material basis and mechanism of its antiasthmatic effect are still unclear. Lignans are the main active components of S. chinensis. The aim of this study was to observe the relaxation effect of S. chinensis lignans (SCL) on the tracheal smooth muscle of rats by in vitro tracheal perfusion experiments, and to explore the mechanism by preincubation with L-type calcium channel blocker verapamil, four potassium channel blockers glibenclamide, tetraethylamine, 4-aminopyridine and barium chloride (BaCl2), ß-adrenoceptor blocker propranolol, nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME), and the cyclooxygenase inhibitor indomethacin, respectively. The results showed that SCL (0.25-1.75 mg/mL) reduced the contraction of isolated tracheal smooth muscle induced by acetylcholine, the preincubation with verapamil and glibenclamide could attenuate the relaxation effect, whereas propranolol, 4-aminopyridine, BaCl2, tetraethylamine, L-NAME, and indomethacin had no such effect. These results suggest that SCL has a significant relaxation effect on the isolated tracheal smooth muscle of rats, and the mechanism may be related to the inhibition of extracellular calcium influx and intracellular calcium release from the sarcoplasmic reticulum, as well as the activation of ATP-sensitive potassium channels. These findings may provide a pharmacological basis for the traditional use of S. chinensis to treat asthma.


Asunto(s)
Lignanos , Schisandra , Animales , Bloqueadores de los Canales de Calcio/farmacología , Lignanos/farmacología , Relajación Muscular , Músculo Liso , Óxido Nítrico , Bloqueadores de los Canales de Potasio/farmacología , Ratas
15.
Sci Total Environ ; 724: 138268, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32408456

RESUMEN

Bamboo shoot shell (BSS), a major byproduct from bamboo shoot industries with a high amount of output annually, needs to be sustainably management due to its impact on environment and human health. Anaerobic digestion is an eco-friendly and sustainable option, but its efficiency is limited by recalcitrance of lignocellulose structure. A cascade pretreatment (CP) using microwave irradiation and fungus metabolism was developed in this work to reduce the recalcitrance of BSS and enhance its methane production. The results showed significant synergistic effects of microwave irradiation and fungus metabolism on anaerobic digestion of BBS. The methane yield by CP increased by 162.9% (reached to 223.4 mL/g VS) when compared to control group. This was higher than both the values of fungal pretreatment (101.0 mL/g VS, 18.9% increase), and microwave pretreatment (110.5 mL/g VS, 30.1% increase) alone. Further mechanisms of the synergistic effects were revealed. Microwave irradiation provided dissolved products and more accessible BBS for fungus action. In particular, the GC-MS analysis indicated the dissolved products induced fungal laccase activity effectively, and the highest activity in CP was 1.91-fold higher than that in fungal pretreatment alone. The fungus in cascade process further increased accessible surface area and reducing sugars (20.2-43.2%, which compared to fungal pretreatment alone), and reduced significantly the lignin content (42.2-49.1%) and crystallinity (4.5-8.1%) of BSS.


Asunto(s)
Metano , Microondas , Anaerobiosis , Biocombustibles , Hongos , Lignina
16.
Rev. bras. med. esporte ; Rev. bras. med. esporte;29: e2022_0259, 2023. tab
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1387921

RESUMEN

ABSTRACT Introduction Although Chinese soccer has experienced many updates in its methods, there is still a large gap in players' physical endurance compared to the world powers. Therefore, strengthening soccer players' physical endurance through specific training methods is important in optimizing current performance. Objective Study the application of functional training in soccer players' physical conditioning. Methods 20 junior soccer physical education student-athletes in colleges and universities were selected as the research object. The global functional training was divided into three stages: practice, adaptation, and promotion. Data were compared, integrated, and analyzed before and after the intervention. Results Conducting targeted functional training for soccer players can effectively increase athletes' physical endurance, reducing sports injuries and improving overall fitness scores at the technical and stability level. Conclusion From the research of this article, it can be seen that there is a lack of physical fitness and technical strength in Chinese soccer today. The performance of targeted functional training is relevant and should be applied to soccer training. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.


RESUMO Introdução Embora o futebol chines tenha experimentado muitas atualizações em seus métodos, ainda há uma grande discrepância em termos de resistência física dos jogadores quando comparados às potências mundiais. Portanto, fortalecer a resistência física dos jogadores de futebol através de métodos específicos de treinamento é um importante fator para a otimização do desempenho atual. Objetivo Estudar a aplicação do treinamento funcional no condicionamento físico dos jogadores de futebol. Métodos 20 atletas estudantes de educação física de futebol júnior em faculdades e universidades foram selecionados como objeto de pesquisa. A formação funcional global foi dividida em três etapas: estágio de prática, fase de adaptação e etapa de promoção. Os dados foram comparados, integrados e analisados antes e após a intervenção. Resultados A realização de treinamentos funcionais direcionados para jogadores de futebol pode efetivamente aumentar a resistência física dos atletas, reduzindo a ocorrência de lesões esportivas e melhorando a pontuação geral do condicionamento físico a nível técnico e de estabilidade. Conclusão A partir da pesquisa deste artigo, pode-se ver que há falta de aptidão física e força técnica no futebol chinês atual. A realização de treinamento funcional direcionado é relevante e merece ser aplicado ao treinamento de futebol. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.


RESUMEN Introducción Aunque el fútbol chino ha experimentado muchas actualizaciones en sus métodos, sigue habiendo una gran discrepancia en cuanto a la resistencia física de los jugadores si se compara con las potencias mundiales. Por lo tanto, reforzar la resistencia física de los futbolistas mediante métodos de entrenamiento específicos es un factor importante para optimizar el rendimiento actual. Objetivo Estudiar la aplicación del entrenamiento funcional en el acondicionamiento físico de los futbolistas. Métodos Se seleccionaron como objeto de investigación 20 estudiantes atletas de educación física de fútbol juvenil en colegios y universidades. El entrenamiento funcional global se dividió en tres etapas: etapa de práctica, etapa de adaptación y etapa de promoción. Los datos se compararon, integraron y analizaron antes y después de la intervención. Resultados La realización de un entrenamiento funcional específico para los futbolistas puede aumentar eficazmente la resistencia física de los deportistas, reduciendo la aparición de lesiones deportivas y mejorando la puntuación global de la aptitud a nivel técnico y de estabilidad. Conclusión De la investigación de este artículo se desprende que en el fútbol chino actual hay una falta de aptitud física y de fuerza técnica. El rendimiento del entrenamiento funcional dirigido es relevante y merece ser aplicado al entrenamiento del fútbol. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

17.
Sci Total Environ ; 635: 576-585, 2018 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-29679830

RESUMEN

The Sichuan and Chongqing regions suffer from severe haze weather in winter due to the unfavourable atmospheric diffusion conditions. Reanalysis and precipitation datasets were applied in this study to calculate and distinguish air stagnation events using a developed criterion, and the impacts of the occurrence of air stagnation events on air quality were analysed in combination with the PM2.5 concentration data for the winters of 2013-2016. The highest occurrence frequency of air stagnation events was observed in 2013, and the lowest, 2015. The meteorological conditions during winter in the Sichuan Basin were inclined to form unfavourable atmospheric diffusion conditions, and the occurrence frequency of air stagnation days was up to 76.6% on average during the four winters. The effects of air stagnation events on air quality were most obvious in the western and southern Sichuan Basin. The mean concentrations of PM2.5 during air stagnation days were higher by 41.9% than those during non-air stagnation days. The PM2.5 concentrations were adjusted using the favourable atmospheric diffusion conditions in 2015 as a baseline to quantify the PM2.5 contribution to the improvement of air quality in the other years, which revealed that the level of PM2.5 in the Sichuan and Chongqing regions was declining at a rate of approximately 10.7% overall during the winters of 2013-2016, implying that the air pollutant reduction measures have been highly effective. Furthermore, the occurrence frequency of air stagnation days and events were increased in recent ten years of 2007-2016, with linear slopes of 0.61yr-1 and 0.26yr-1, respectively. The study revealed that the government might face a greater challenge in improving the air quality over winter and should pay more attention to reduction of pollutant emission in areas of Chengdu, Chongqing and cities in the south of the Sichuan Basin.


Asunto(s)
Movimientos del Aire , Contaminación del Aire/estadística & datos numéricos , Monitoreo del Ambiente , Contaminantes Atmosféricos/análisis , China , Ciudades , Material Particulado/análisis
18.
J Phys Chem B ; 121(34): 8188-8194, 2017 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-28792754

RESUMEN

Increasing the thermostability of amorphous materials has been a long journey to improve their properties. The metastable nature of chalcogenide glasses limits their practical applications as an amorphous semiconductor in photovoltaic performance. Here, we report the formation and physical properties of ultrastable amorphous Sb2Se3 with an enhanced thermal stability compared to ordinary amorphous Sb2Se3 (ΔTx= 17 K). By in situ high temperature-high energy synchrotron X-ray diffraction, the difference in structure relaxation between ordinary and ultrastable amorphous Sb2Se3 was manifested by local structure evolution. Ultrastable amorphous Sb2Se3 showed the smallest surface roughness and highest refractive index, the mechanism behind was further discussed in terms of fast molecular mobility and molecular orientation during vapor deposition. Formation of ultrastable amorphous Sb2Se3 demonstrated a promising avenue to obtain novel functional amorphous semiconductor with modulated structure and property.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA