Signature of elasticity in the Faraday instability

We investigate the onset of the Faraday instability in a vertically vibrated wormlike micelle solution. In this strongly viscoelastic fluid, the critical acceleration and wavenumber are shown to present oscillations as a function of driving frequency and fluid height. This effect, unseen neither in simple fluids nor in previous experiments on polymeric fluids, is interpreted in terms of standing elastic waves between the disturbed surface and the container bottom. It is shown that the model of S. Kumar [Phys. Rev. E, {\bf 65}, 026305 (2002)] for a viscoelastic fluid accounts qualitatively for our experimental observations. Explanations for quantitative discrepancies are proposed, such as the influence of the nonlinear rheological behaviour of this complex fluid.Comment: 4 pages, 4 figure

Pensamiento matemático y creatividad a través de la invención y resolución de problemas matemáticos

This work shows the relationship between the development of mathematical thinking and creativity with mathematical problem posing and solving. Creativity and mathematics are disciplines that do not usually appear together. Both concepts constitute complex processes sharing elements, such as fluency (number of ideas), flexibility (range of ideas), novelty (unique idea) and elaboration (idea development). These factors contribute, among others, to the fact that schoolchildren are competent in mathematics. The problem solving and posing are a very powerful evaluation tool that shows the mathematical reasoning and creative level of a person. Creativity is part of the mathematics education and is a necessary ingredient to perform mathematical assignments. This contribution presents some important research works about problem posing and solving related to the development of mathematical knowledge and creativity. To that end, it is based on various beliefs reflected in the literature with respect to notions of creativity, problem solving and posing.En este trabajo se muestra la relación entre el desarrollo del pensamiento matemático y la creatividad con la invención y resolución de problemas matemáticos. No son frecuentes las ocasiones en las que aparecen juntas Creatividad y Matemáticas. Ambas constituyen procesos complejos que comparten elementos como la fluidez (número de ideas), la flexibilidad (variedad de ideas), la novedad (idea única) y la elaboración (desarrollar una idea). Estos factores contribuyen, entre otras cosas, a que los escolares sean competentes en matemáticas. La invención y la resolución de problemas resultan ser un instrumento evaluador muy potente con el que se pone de manifiesto el nivel de razonamiento matemático y creativo de una persona. La creatividad forma parte de la educación matemática y constituye un ingrediente necesario para realizar las tareas matemáticas. Esta aportación presenta algunas investigaciones relevantes, que se han llevado a cabo sobre invención y resolución de problemas, vinculadas al desarrollo del conocimiento matemático y a la creatividad. Para ello se parte de las distintas creencias que se recogen en la literatura referente a las nociones de creatividad, invención de problemas y resolución de problemas

Pensamiento matemático y creatividad a través de la invención y resolución de problemas matemáticos

This work shows the relationship between the development of mathematical thinking and creativity with mathematical problem posing and solving. Creativity and mathematics are disciplines that do not usually appear together. Both concepts constitute complex processes sharing elements, such as fluency (number of ideas), flexibility (range of ideas), novelty (unique idea) and elaboration (idea development). These factors contribute, among others, to the fact that schoolchildren are competent in mathematics. The problem solving and posing are a very powerful evaluation tool that shows the mathematical reasoning and creative level of a person. Creativity is part of the mathematics education and is a necessary ingredient to perform mathematical assignments. This contribution presents some important research works about problem posing and solving related to the development of mathematical knowledge and creativity. To that end, it is based on various beliefs reflected in the literature with respect to notions of creativity, problem solving and posing.En este trabajo se muestra la relación entre el desarrollo del pensamiento matemático y la creatividad con la invención y resolución de problemas matemáticos. No son frecuentes las ocasiones en las que aparecen juntas Creatividad y Matemáticas. Ambas constituyen procesos complejos que comparten elementos como la fluidez (número de ideas), la flexibilidad (variedad de ideas), la novedad (idea única) y la elaboración (desarrollar una idea). Estos factores contribuyen, entre otras cosas, a que los escolares sean competentes en matemáticas. La invención y la resolución de problemas resultan ser un instrumento evaluador muy potente con el que se pone de manifiesto el nivel de razonamiento matemático y creativo de una persona. La creatividad forma parte de la educación matemática y constituye un ingrediente necesario para realizar las tareas matemáticas. Esta aportación presenta algunas investigaciones relevantes, que se han llevado a cabo sobre invención y resolución de problemas, vinculadas al desarrollo del conocimiento matemático y a la creatividad. Para ello se parte de las distintas creencias que se recogen en la literatura referente a las nociones de creatividad, invención de problemas y resolución de problemas

Unconventional Oil and Gas Development: Evaluation of selected hydrocarbons in the ambient air of three basins in the United States by means of diffusive sampling measurements

The impact of emissions associated with the extraction of crude oil and natural gas upon air quality in the United States (US) is widely recognised to have an impact on climate change, human health and ground-level ozone formation. A number of measurement approaches are being applied to evaluate the environmental impact of the oil and gas (O&G) sector, including satellite, airborne and ground-based platforms. Measurement based studies, in particular those that estimate flux rates, are critical for the validation of emission inventories that often under-report actual emissions of methane and volatile organic compounds (VOC) from the O&G sector. On-going research projects in the US are investigating the consistency of emission rates from O&G emission sources associated with extraction, transmission and distribution activities. The leakage rates of methane, as related to production levels, in the US for O&G developments varies from less than 1% (e.g. Upper Green River Basin, Wyoming) to over 6% (Uintah Basin, Utah). European research and policy approaches can learn from efforts in the US that are improving the accuracy of reporting emissions from O&G sources, enhancing our understanding of air quality impacts, and reducing emissions through regulatory controls. The Joint Research Centre (JRC) of the European Commission performed a diffusive sampling project, with the collaboration of the University of Wyoming, in conjunction with the SONGNEX (Studying the Atmospheric Effects of Changing Energy Use in the US at the Nexus of Air Quality and Climate Change) project led by the US National Oceanic and Atmospheric Administration. The SONGNEX project is an airborne measurement campaign supported by a number of associated ground based studies. The applicability of the Pocket Diffusive (PoD) sampler, for measurement of VOC (C4-C10), heavy hydrocarbons and volatile polycyclic aromatic hydrocarbons (PAHs) in areas heavily influenced by O&G development, is evaluated. Three sampling surveys were performed to assess three basins (Upper Green River, Uintah and North Platte) characterised by different management regimes, meteorology and hydrocarbon products. This first extensive field deployment of the PoD sampler demonstrates the effectiveness of the sampler for time-integrated measurements of targeted pollutants over wide spatial areas. The ambient air at these basins reveal different compositional profiles of hydrocarbons (C4-C10). Analysis of aromatics supports a finding of relatively elevated levels in the Pinedale Anticline (Upper Green River). From an evaluation of the behaviour of alkanes, it is evident that there is a relatively high leakage rate in the Uintah Basin. Heavy hydrocarbons (C11-C22) and PAHs are measured at relatively low levels. Despite low concentrations, analysis of these compounds improves the accuracy of source identification. A comparison of ground based PoD data and airborne SONGNEX data showed good agreement for commonly reported VOCs. The utility of the PoD sampler for analysis of emission sources was enhanced with reporting of a wide range of compounds. Spatial Positive Matrix Factorization analysis showed the possibility of using PoD samplers for differentiating emission sources, characterizing different areas and estimating the relative contribution of different emission sources.JRC.C.5-Air and Climat

Systems chronotherapeutics

Chronotherapeutics aim at treating illnesses according to the endogenous biologic rhythms, which moderate xenobiotic metabolism and cellular drug response. The molecular clocks present in individual cells involve approximately fifteen clock genes interconnected in regulatory feedback loops. They are coordinated by the suprachiasmatic nuclei, a hypothalamic pacemaker, which also adjusts the circadian rhythms to environmental cycles. As a result, many mechanisms of diseases and drug effects are controlled by the circadian timing system. Thus, the tolerability of nearly 500 medications varies by up to fivefold according to circadian scheduling, both in experimental models and/or patients. Moreover, treatment itself disrupted, maintained, or improved the circadian timing system as a function of drug timing. Improved patient outcomes on circadian-based treatments (chronotherapy) have been demonstrated in randomized clinical trials, especially for cancer and inflammatory diseases. However, recent technological advances have highlighted large interpatient differences in circadian functions resulting in significant variability in chronotherapy response. Such findings advocate for the advancement of personalized chronotherapeutics through interdisciplinary systems approaches. Thus, the combination of mathematical, statistical, technological, experimental, and clinical expertise is now shaping the development of dedicated devices and diagnostic and delivery algorithms enabling treatment individualization. In particular, multiscale systems chronopharmacology approaches currently combine mathematical modeling based on cellular and whole-body physiology to preclinical and clinical investigations toward the design of patient-tailored chronotherapies. We review recent systems research works aiming to the individualization of disease treatment, with emphasis on both cancer management and circadian timing system–resetting strategies for improving chronic disease control and patient outcomes

Osteoporosis transitoria de la cadera: revisión de aspectos clínicos y terapéuticos a propósito de un caso

Presentamos el caso de una mujer de 17 años con osteoporosis transitoria de cadera (OTC). La OTC es una enfermedad infrecuente, difícil de etiquetar, que afecta a hombres sanos de mediana edad, y a mujeres en el tercer trimestre del embarzo. Su etiología todavía no está clara. Los principales signos clínicos son dolor en la cadera y cojera. La RM muestra en la cabeza y cuello femoral hipointensidad en las imágenes ponderadas en T1, e hiperintensidad en las imágenes ponderadas en T2. Se acepta que los cambios en la RM se producen por incremento de líquido en la cavidad medular de la cabeza femoral. Es importante el diagnóstico diferencial con otras enfermedades de la cadera. El propósito de esta publicación es aclarar los aspectos diagnósticos y terapéuticos de la OTC.A case of transient osteoporosis of the hips in a 17-year-old-woman is reported. Transient osteoporosis of the hip (TOH) is an uncommon but possibly underdiagnosed condition. The TOH affects previous healthy middle-age men, and women in the third trimester of pregnancy. Its etiology is still unclear. Pain in the hip area and limp are the main clinical signs. The MRI study shows low signal intensity on the Tl weighted images and limp signal intensity on the T2 weighted images in the femoral head and neck. It is generally accepted that the change in MRI is caused by an increase in fluid within the marrow cavities of the femoral head. Differential diagnosis of hip problems is required. The purpose of this report is to review the diagnostic and therapeutic aspects of TOH

Photodynamic Therapy Combined with Antibiotics or Antifungals against Microorganisms That Cause Skin and Soft Tissue Infections: A Planktonic and Biofilm Approach to Overcome Resistances

The present review covers combination approaches of antimicrobial photodynamic therapy (aPDT) plus antibiotics or antifungals to attack bacteria and fungi in vitro (both planktonic and biofilm forms) focused on those microorganisms that cause infections in skin and soft tissues. The combination can prevent failure in the fight against these microorganisms: antimicrobial drugs can increase the susceptibility of microorganisms to aPDT and prevent the possibility of regrowth of those that were not inactivated during the irradiation; meanwhile, aPDT is effective regardless of the resistance pattern of the strain and their use does not contribute to the selection of antimicrobial resistance. Additive or synergistic antimicrobial effects in vitro are evaluated and the best combinations are presented. The use of combined treatment of aPDT with antimicrobials could help overcome the difficulty of fighting high level of resistance microorganisms and, as it is a multi-target approach, it could make the selection of resistant microorganisms more difficult

A combined experimental and mathematical approach for molecular-based optimization of irinotecan circadian delivery

Circadian timing largely modifies efficacy and toxicity of many anticancer drugs. Recent findings suggest that optimal circadian delivery patterns depend on the patient genetic background. We present here a combined experimental and mathematical approach for the design of chronomodulated administration schedules tailored to the patient molecular profile. As a proof of concept we optimized exposure of Caco-2 colon cancer cells to irinotecan (CPT11), a cytotoxic drug approved for the treatment of colorectal cancer. CPT11 was bioactivated into SN38 and its efflux was mediated by ATP-Binding-Cassette (ABC) transporters in Caco-2 cells. After cell synchronization with a serum shock defining Circadian Time (CT) 0, circadian rhythms with a period of 26 h 50 (SD 63 min) were observed in the mRNA expression of clock genes REV-ERBα, PER2, BMAL1, the drug target topoisomerase 1 (TOP1), the activation enzyme carboxylesterase 2 (CES2), the deactivation enzyme UDP-glucuronosyltransferase 1, polypeptide A1 (UGT1A1), and efflux transporters ABCB1, ABCC1, ABCC2 and ABCG2. DNA-bound TOP1 protein amount in presence of CPT11, a marker of the drug PD, also displayed circadian variations. A mathematical model of CPT11 molecular pharmacokinetics-pharmacodynamics (PK-PD) was designed and fitted to experimental data. It predicted that CPT11 bioactivation was the main determinant of CPT11 PD circadian rhythm. We then adopted the therapeutics strategy of maximizing efficacy in non-synchronized cells, considered as cancer cells, under a constraint of maximum toxicity in synchronized cells, representing healthy ones. We considered exposure schemes in the form of an initial concentration of CPT11 given at a particular CT, over a duration ranging from 1 to 27 h. For any dose of CPT11, optimal exposure durations varied from 3h40 to 7h10. Optimal schemes started between CT2h10 and CT2h30, a time interval corresponding to 1h30 to 1h50 before the nadir of CPT11 bioactivation rhythm in healthy cells