Fluorine-free omniphobic slippery surfaces made of PDMS-like molecules: surface structure and wetting properties

International audienceSurfaces covered with omniphobic coatings are investigated for many applications from anti-icing, anti-corrosive to self-cleaning uses as they allow droplets of many liquids to easily slide without pinning. To this end, PDMS-like molecules can be grafted onto glass substrates by specific process conditions 1,2. These molecules are supposedly covalently grafted to the substrate, leading to the fabrication of omniphobic surfaces with low sliding angles and low hysteresis (< 10°) for a broad range of liquids. By studying the influence of the fabrication process on the surface structure and wetting properties (contact angles CA, hysteresis CAH and sliding angles SA) of the coated substrate, we highlight here the key features that lead to a highly slippery PDMS-based coating

A silicone-based slippery polymer coating with humidity–dependent nanoscale topography

International audienceHypothesis: Slippery Omniphobic Covalently Attached Liquids (SOCAL) have been proposed for making omnirepellent thin films of self-assembled dimethylsiloxane polymerbrushes grafted from silica surfaces. Smooth and flat at very small scale, these fluid surfaces could exhibit a more complex multiscale structure though showing very weak contact angle hysteresis (less than 5°).Experiment: In this work, coatings were deposited on glass surfaces from an acidic dimethoxydimethylsilane solution under carefully controlled relative humidity. Ellipsometry mapping was used to analyze the surface structuration with nanometric thickness sensitivity. The sliding properties were determined using a drop shape analyzer with a tilting device, and chemical analyses of the coatings were performed using on-surface techniques (XPS, ATR-FTIR spectroscopy).Findings: Coated materials possessed an unexpected surface structure with multiscale semispherical-like features, which surprisingly, did not increase the contact angle hysteresis. A careful study of some parameters of the coating process and the related evolution of the surface properties allowed us to propose a new model of the chemical organization of the polymer to support this remarkable liquid-like behavior. These structures are made of endgrafted strongly adsorbed Guiselin brushes with humidity-dependent thickness: the higher the humidity, the thinner and the more slippery the coating

Exhibition QIM-based watermarking for digital cinema

The copyright protection of digital cinema requires the insertion of forensic watermarks during exhibition playback. This paper presents a low-complexity exhibition watermarking method based on quantization index modulation (QIM) and embedded in the DCI compliant decoder. Watermark embedding is proposed to fit in the JPEG2000 decoding process, prior to the inverse wavelet transform and such as it has a minimal impact on the image quality, guarantying a strong link between decompression and watermarking. The watermark is embedded by using an adaptive-spread transform dither modulation (STDM) method, based on a new multi-resolution perceptual masking to adapt watermark strength. Watermark detection is thereafter performed over the wavelet transformation of the recovered images. The proposed approach offers a wide range of channel capacities according to robustness to several kinds of distortions while maintaining a low computational complexity. Watermarking detection performance on digital cinema pictures captured with a video camera from a viewing room has been preliminary assessed, showing very promising results. The proposed approach provides high levels of imperceptibility, yet good robustness to degradations resulting from camcorder exhibition capture, to common signal processing operations such as filtering or re-sampling, and to very high compression.Anglai

Secure and HVS-adaptive exhibition spread transform dither modulation watermarking for digital cinema

In this paper, we propose a secure watermarking scheme based on spread transform dither modulation (STDM) method for digital cinema. The embedding is performed in the JPEG2000 decoding pipeline after the de-quantization and prior to the inverse discrete wavelet transform (IDWT). We exploit the wavelet properties related to the human visual system (HVS) in order to have a trade-off between fidelity and robustness, while preserving security. We design a pixel-wise masking vector that modulates the spreading vector in such a way that preserves its security. Our results show that the proposed method is robust against traditional image processing attacks. The proposed scheme can also survive the camecording attack, a pre-processing step is done in the detection for this end.Anglai

Disociación histo-radiológica en fibrosis pulmonar secundaria a infección por SARS-CoV-2

Sr. Editor: La reciente declarada pandemia de COVID-19 por la Organización Mundial de la Salud (OMS) a causa del nuevo coronavirus SARS-CoV-2 identificado en la ciudad de Wuhan (China) en diciembre de 20191, ha conseguido poner a prueba a todos los sistemas de salud mundial. La fisiopatología de esta infección todavía no se conoce con exactitud, y la efectividad de los tratamientos hasta ahora disponibles está aún por demostrar. La insuficiencia respiratoria hipoxémica es causa de la mayoría de los ingresos en las unidades de cuidados intensivos (UCI), con una necesidad de ventilación mecánica invasiva (VMI) de hasta el 88% en algunas series2. Presentamos el caso de una mujer de 53 años, originaria de Nicaragua y trabajadora en residencia de ancianos, con antecedentes de hipotiroidismo en tratamiento sustitutivo y obesidad con índice de masa corporal de 28 kg/m2. Ingresó en nuestra UCI procedente de planta por insuficiencia respiratoria por COVID-19 con sintomatología de 15 días de evolución, habiendo recibido previamente tratamiento con azitromicina, lopinavir/ritonavir, hidroxicloroquina y metilprednisolona a dosis de 1 mg/kg/24 h. Al ingreso se inició oxigenoterapia de alto flujo con tórpida evolución, requiriendo a las 48 h intubación orotraqueal y conexión a VMI por..

Implicación del estrés oxidativo en las enfermedades neurodegenerativas y posibles terapias antioxidantes

Objetivos: El sistema nervioso central es fundamental en el control de la homeostasis y mantenimiento de las funciones fisiológicas del organismo. Sin embargo, sus características bioquímicas hacen que sea especialmente vulnerable al daño oxidativo, lo que compromete su correcto funcionamiento, desencadenando neurodegeneración y muerte neuronal. Contenido: El estrés oxidativo desempeña un papel importante en la fisiopatología de las enfermedades neurodegenerativas dado que participa en multitud de mecanismos que inducen oxidación de ácidos nucleicos, proteínas y lípidos, contribuyendo con ello, al daño cerebral progresivo. Entre estos mecanismos se encuentran la disfunción mitocondrial, generación excesiva de especies reactivas de oxígeno y nitrógeno, déficit de defensas antioxidantes, oligomerización de proteínas, producción de citoquinas y respuesta inflamatoria, alteración de la barrera hematoencefálica o disfunción del proteasoma. Todas estas disfunciones se han visto implicadas en la patogénesis de diversas enfermedades neurodegenerativas, como la enfermedad de Parkinson, Alzheimer, Huntington o esclerosis lateral amiotrófica. Resumen y perspectivas: Aunque actualmente no existen tratamientos curativos, las investigaciones se han dirigido a la búsqueda de terapias que permitan reducir el daño secundario al estrés oxidativo y ralentizar la evolución de la enfermedad. Es aquí donde las investigaciones sobre el efecto de las terapias antioxidantes muestran un papel activo

The role of oxidative stress in neurodegenerative diseases and potential antioxidant therapies

Objectives: The central nervous system (CNS) is essential for homeostasis and controls the physiological functions of the body. However, the biochemical characteristics of the CNS make it especially vulnerable to oxidative damage (OS). This phenomenon compromises correct CNS functioning, leading to neurodegeneration and neuronal death. Contents: OS plays a crucial role in the physiopathology of neurodegenerative diseases. It is involved in multiple mechanisms of nucleic acid, protein, and lipid oxidation, thereby contributing to progressive brain damage. These mechanisms include mitochondrial dysfunction; excessive production of reactive oxygen and nitrogen species; deficiency of antioxidant defenses; protein oligomerization; cytokine production and inflammatory response; blood–brain barrier abnormalities; and proteasome dysfunction. All these dysfunctions are involved in the pathogenesis of neurodegenerative diseases, including Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, or amyotrophic lateral sclerosis. Summary and outlook: A curative treatment is currently not available. Research is focused on the search for therapies that reduce oxidative damage and delay disease progression. In the recent years, researchers have focused their attention on the effects of antioxidant therapies

Position statement for the development of adult congenital heart disease units in Latin America and the Caribbean: Recommendations by the adult congenital heart disease chapter and pediatric cardiology council of the interamerican society of cardiology …

In 2020, there was an estimated prevalence of more than 1.8 million adults with congenital heart disease (ACHDs) living in South America, and 677,000 in Central America and the Caribbean. The ACHD mortality is higher in developing countries, compared with developed countries, and it has been shown that concentrating this population in specialized ACHD units improves their survival and prognosis. Currently, Latin American (LATAM) and Caribbean countries have an insufficient number of specialists and specialized ACHD units. Analyzing this situation, the Inter-American Society of Cardiology's (IASC) ACHD chapter and Pediatric Cardiology Council have prepared the first recommendations for developing ACHD units in LATAM and Caribbean countries. This article is the first collaborative work between South American, Central American and Caribbean countries. It describes the main points for organizing and developing ACHD units adapted to our own reality. Each point has been discussed in terms of barriers and challenges, followed by specific recommendations for improving and developing ACHD care. They have been reviewed and endorsed by the International Society for Adult Congenital Heart Disease (ISACHD), and the goal of their implementation is for each ACHD unit in the region to have the standards of quality and efficiency to improve the prognosis and survival of ACHDs in the region