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1.
Artigo em Inglês | MEDLINE | ID: mdl-37030810

RESUMO

Video watermarking embeds a message into a cover video in an imperceptible manner, which can be retrieved even if the video undergoes certain modifications or distortions. Traditional watermarking methods are often manually designed for particular types of distortions and thus cannot simultaneously handle a broad spectrum of distortions. To this end, we propose a robust deep learning-based solution for video watermarking that is end-to-end trainable. Our model consists of a novel multiscale design where the watermarks are distributed across multiple spatial-temporal scales. Extensive evaluations on a wide variety of distortions show that our method outperforms traditional video watermarking methods as well as deep image watermarking models by a large margin. We further demonstrate the practicality of our method on a realistic video-editing application.

2.
iScience ; 25(8): 104808, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35992064

RESUMO

The rapid development of distributed photovoltaic (PV) systems poses great challenges to the integration capability of distribution networks. Traditionally, the transfer capacity of power distribution equipment is calculated as the maximum loading that prevents overheating under the assumption of extreme weather conditions. Dynamic thermal rating (DTR), which evaluates equipment capacity based on real-time weather conditions, could enhance the transfer capacity to improve distributed PV integration. Through case studies in Texas, Switzerland, and China, we show that the application of DTR on power distribution equipment could increase installed PV capacities by 15%-27% and improve net revenues by 4%-27%. We also find that the application of DTR would be positively affected by climate change and is more profitable under the PV policies with higher tariffs for the surplus generation fed into the grid. Compared to energy storage systems, DTR provides a more cost-competitive option to enhance the integration capability of distribution networks.

3.
ACS Nano ; 13(3): 3363-3372, 2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30836750

RESUMO

Evaporation from nanopores plays an important role in various natural and industrial processes that require efficient heat and mass transfer. The ultimate performance of nanopore-evaporation-based processes is dictated by evaporation kinetics at the liquid-vapor interface, which has yet to be experimentally studied down to the single nanopore level. Here we report unambiguous measurements of kinetically limited intense evaporation from individual hydrophilic nanopores with both hydrophilic and hydrophobic top outer surfaces at 22 °C using nanochannel-connected nanopore devices. Our results show that the evaporation fluxes of nanopores with hydrophilic outer surfaces show a strong diameter dependence with an exponent of nearly -1.5, reaching up to 11-fold of the maximum theoretical predication provided by the classical Hertz-Knudsen relation at a pore diameter of 27 nm. Differently, the evaporation fluxes of nanopores with hydrophobic outer surfaces show a different diameter dependence with an exponent of -0.66, achieving 66% of the maximum theoretical predication at a pore diameter of 28 nm. We discover that the ultrafast diameter-dependent evaporation from nanopores with hydrophilic outer surfaces mainly stems from evaporating water thin films outside of the nanopores. In contrast, the diameter-dependent evaporation from nanopores with hydrophobic outer surfaces is governed by evaporation kinetics inside the nanopores, which indicates that the evaporation coefficient varies in different nanoscale confinements, possibly due to surface-charge-induced concentration changes of hydronium ions. This study enhances our understanding of evaporation at the nanoscale and demonstrates great potential of evaporation from nanopores.

4.
Nano Lett ; 17(8): 4813-4819, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28719216

RESUMO

Capillary evaporation in nanoscale conduits is an efficient heat/mass transfer strategy that has been widely utilized by both nature and mankind. Despite its broad impact, the ultimate transport limits of capillary evaporation in nanoscale conduits, governed by the evaporation/condensation kinetics at the liquid-vapor interface, have remained poorly understood. Here we report experimental study of the kinetic limits of water capillary evaporation in two dimensional nanochannels using a novel hybrid channel design. Our results show that the kinetic-limited evaporation fluxes break down the limits predicated by the classical Hertz-Knudsen equation by an order of magnitude, reaching values up to 37.5 mm/s with corresponding heat fluxes up to 8500 W/cm2. The measured evaporation flux increases with decreasing channel height and relative humidity but decreases as the channel temperature decreases. Our findings have implications for further understanding evaporation at the nanoscale and developing capillary evaporation-based technologies for both energy- and bio-related applications.

5.
Sci Rep ; 6: 24936, 2016 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-27112404

RESUMO

Nanoscale liquid transport governs the behaviour of a wide range of nanofluidic systems, yet remains poorly characterized and understood due to the enormous hydraulic resistance associated with the nanoconfinement and the resulting minuscule flow rates in such systems. To overcome this problem, here we present a new measurement technique based on capillary flow and a novel hybrid nanochannel design and use it to measure water transport through single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our results show that silica nanochannels exhibit increased mass flow resistance compared to the classical hydrodynamics prediction. This difference increases with decreasing channel height and reaches 45% in the case of 7 nm nanochannels. This resistance increase is attributed to the formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. By avoiding use of any pressure and flow sensors or any theoretical estimations the hybrid nanochannel scheme enables facile and precise flow measurement through single nanochannels, nanotubes, or nanoporous media and opens the prospect for accurate characterization of both hydrophilic and hydrophobic nanofluidic systems.

6.
Langmuir ; 31(44): 12291-9, 2015 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-26411775

RESUMO

In this work, we study silicon nanowire synthesis via one-step metal-assisted chemical etching (MACE) on microstructured silicon surfaces with periodic pillar/cavity array. It is found that hydrogen gas produced from the initial anodic reaction can be trapped inside cavities and between pillars, which serves as a mask to prevent local etching, and leads to the formation of patterned vertically aligned nanowire array. A simple model is presented to demonstrate that such bubble entrapment is due to the significant adhesion energy barrier, which is a function of pillar/cavity geometry, contact angle, and nanowire length to be etched. The bubble entrapment can be efficiently removed when extra energy is introduced by sonication to overcome this energy barrier, resulting in nanowire growth in all exposed surfaces. This bubble-regulated MACE process on microstructured surfaces can be used to fabricate nanowire arrays with desired morphologies.

7.
Int J Cardiol ; 167(2): 436-41, 2013 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-22293779

RESUMO

BACKGROUND: An increase in cardiac M2-muscarinic receptor (M2-mAChR) expression in diabetic rats has been observed, but the molecular mechanism of this increase remains unclear. The transcriptional activity of GATA binding protein 4 (GATA-4) has been documented to regulate the expression of M2-mAChR genes. In this study, we were interested in identifying the role of GATA-4 in the increase in M2-mAChR in diabetic rats and a primary culture of cardiomyocytes. METHODS: Streptozotocin-induced diabetic rats (STZ-rats) and high-glucose (D-glucose 30 mM, 24h)-treated primary cultures of cardiomyocytes from neonatal rats were used to investigate the role of GATA-4 in the change in M2-mAChR. The protein expression was determined by Western blot analysis. Phlorizin (Na(+)-glucose co-transport inhibitor), insulin, tiron (radical scavenger), PD98059 (ERK inhibitor) and SB203580 (p38 inhibitor) were used. We also silenced GATA-4 by RNAi to investigate the changes in M2-mAChR expression. RESULTS: The cardiac output was reduced in STZ-rats with a higher expression of M2-mAChR or phosphorylated GATA-4 in the heart. These changes were reversed after correction of the blood sugar level. In cardiomyocytes, high glucose treatment also increased M2-mAChR expression and GATA-4 phosphorylation. These changes were reversed by tiron (ROS scavenger) or PD98059 (MEK/ERK inhibitor). However, an increase in M2-mAChR expression was not observed when GATA-4 was silenced by small interfering RNA (siRNA) in cardiomyocytes. CONCLUSIONS: We suggest that hyperglycemia can cause a higher expression of M2-mAChR in cardiomyocytes mainly through ROS to enhance MEK/ERK for phosphorylation of GATA-4.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Fator de Transcrição GATA4/fisiologia , Regulação da Expressão Gênica , Miócitos Cardíacos/metabolismo , Receptor Muscarínico M2/biossíntese , Animais , Débito Cardíaco/fisiologia , Células Cultivadas , Diabetes Mellitus Experimental/genética , Coração/fisiologia , Masculino , Ratos , Ratos Wistar , Receptor Muscarínico M2/genética
8.
ScientificWorldJournal ; 2012: 248320, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22666095

RESUMO

Recent evidence showed the role of peroxisome proliferator-activated receptors (PPARs) in cardiac function. Cardiac contraction induced by various agents is critical in restoring the activity of peroxisome proliferator-activated receptors δ (PPARδ) in cardiac myopathy. Because dobutamine is an agent widely used to treat heart failure in emergency setting, this study is aimed to investigate the change of PPARδ in response to dobutamine. Neonatal rat cardiomyocytes were used to examine the effects of dobutamine on PPARδ expression levels and cardiac troponin I (cTnI) phosphorylation via Western blotting analysis. We show that treatment with dobutamine increased PPARδ expression and cTnI phosphorylation in a time- and dose-dependent manner in neonatal rat cardiomyocytes. These increases were blocked by the antagonist of ß1-adrenoceptors. Also, the action of dobutamine was related to the increase of calcium ions and diminished by chelating intracellular calcium. Additionally, dobutamine-induced action was reduced by the inhibition of downstream messengers involved in this calcium-related pathway. Moreover, deletion of PPARδ using siRNA generated the reduction of cTnI phosphorylation in cardiomyocytes treated with dobutamine. Thus, we concluded that PPARδ is increased by dobutamine in cardiac cells.


Assuntos
Agonistas de Receptores Adrenérgicos beta 1/farmacologia , Dobutamina/farmacologia , Coração/efeitos dos fármacos , PPAR delta/metabolismo , Animais , Animais Recém-Nascidos , Western Blotting , Cálcio/metabolismo , Miocárdio/citologia , Fosforilação , Ratos
9.
Cardiovasc Diabetol ; 10: 57, 2011 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-21702924

RESUMO

BACKGROUND: Diabetic cardiomyopathy, a diabetes-specific complication, refers to a disorder that eventually leads to left ventricular hypertrophy in addition to diastolic and systolic dysfunction. In recent studies, hyperglycemia-induced reactive oxygen species (ROS) in cardiomyocytes have been linked to diabetic cardiomyopathy. GATA binding protein 4 (GATA-4) regulates the expression of many cardio-structural genes including cardiac troponin-I (cTnI). METHODS: Streptozotocin-induced diabetic rats and H9c2 embryonic rat cardiomyocytes treated with a high concentration of glucose (a D-glucose concentration of 30 mM was used and cells were cultured for 24 hr) were used to examine the effect of hyperglycemia on GATA-4 accumulation in the nucleus. cTnI expression was found to be linked to cardiac tonic dysfunction, and we evaluated the expression levels of cTnI and GATA-4 by Western blot analysis. RESULTS: Cardiac output was lowered in STZ-induced diabetic rats. In addition, higher expressions of cardiac troponin I (cTnI) and phosphorylated GATA-4 were identified in these rats by Western blotting. The changes were reversed by treatment with insulin or phlorizin after correction of the blood sugar level. In H9c2 cells, ROS production owing to the high glucose concentration increased the expression of cTnI and GATA-4 phosphorylation. However, hyperglycemia failed to increase the expression of cTnI when GATA-4 was silenced by small interfering RNA (siRNA) in H9c2 cells. Otherwise, activation of ERK is known to be a signal for phosphorylation of serine105 in GATA-4 to increase the DNA binding ability of this transcription factor. Moreover, GSK3ß could directly interact with GATA-4 to cause GATA-4 to be exported from the nucleus. GATA-4 nuclear translocation and GSK3ß ser9 phosphorylation were both elevated by a high glucose concentration in H9c2 cells. These changes were reversed by tiron (ROS scavenger), PD98059 (MEK/ERK inhibitor), or siRNA of GATA-4. Cell contractility measurement also indicated that the high glucose concentration decreased the contractility of H9c2 cells, and this was reduced by siRNA of GATA-4. CONCLUSIONS: Hyperglycemia can cause systolic dysfunction and a higher expression of cTnI in cardiomyocytes through ROS, enhancing MEK/ERK-induced GATA-4 phosphorylation and accumulation in the cell nucleus.


Assuntos
Débito Cardíaco/fisiologia , Cardiomegalia/etiologia , Cardiomegalia/metabolismo , Diabetes Mellitus Experimental/complicações , Fator de Transcrição GATA4/metabolismo , Hiperglicemia/complicações , Contração Miocárdica/fisiologia , Animais , Cardiomegalia/fisiopatologia , Núcleo Celular/metabolismo , Células Cultivadas , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glucose/farmacologia , Hiperglicemia/metabolismo , Hiperglicemia/fisiopatologia , MAP Quinase Quinase Quinases/metabolismo , Masculino , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , RNA Interferente Pequeno/farmacologia , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Estreptozocina/efeitos adversos , Troponina I/metabolismo
10.
Zhongguo Zhen Jiu ; 28(6): 399-401, 2008 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-18630533

RESUMO

OBJECTIVE: To find out a better therapy for paralytic strabismus. METHODS: Ninety cases were randomly divided into an acupuncture-medicine group, an acupuncture group, a western medicine group, 30 cases in each group. The acupuncture-medicine group were treated with acupuncture at Shuigou (GV 26), Fengchi (GB 20), Yifeng (TE 17), Yiming (EX-HN 14), Taiyang (EX-HN 5), Jingming (BL 1), Cuanzhu (BL 2), etc. intramuscular injection of Vit B1 and Vit B12, and oral administration of ATP; the acupuncture group were treated with simple acupuncture, and the western medicine group were treated with simple western medicine. Their therapeutic effects were compared. RESULTS: The cured rate of 66.7% in the acupuncture-medicine group was significantly higher than 26.7% in the acupuncture group and 26.7% in the western medicine group (both P < 0.01). CONCLUSION: Acupuncture combined with western medicine has obvious therapeutic effect, which is better than that of simple acupuncture or simple western medicine.


Assuntos
Terapia por Acupuntura , Oftalmoplegia Externa Progressiva Crônica/terapia , Estrabismo/terapia , Idoso , Terapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
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