Thickness effect on the solvent sensing parameters of carbon black-polymer composites

investigación realizada en proyecto de Red TemáticaStudy of the sensing parameters: sensibility, response and recuperation times to hexane vapors for layers of different thickness of poly(butadiene) + carbon black (CB) composites is presented. The results show that sensibility increases as the CB- weight percent diminishes, being in agreement with reported results by several researches. In this work another variable was studied on the sensing parameters, the thickness. The initial electrical resistance of the studied layers increases until three magnitude orders as diminish theirs thickness and the sensibility in this study increases until one magnitude order as the layer thickness diminishes around 0.25 μm.Programa de Mejoramiento al Profesorado (PROMEP, México), proyecto de red PROMEP 2013-2014

Optical properties of carbon nanostructures produced by laser irradiation on chemically modified multi-walledcarbon nanotubes

Apoyo a la Red Temática de Colaboración Académica: Desarrollo de Materiales Compuestos con propiedades Ópticas, Eléctricas , Magnéticas y sus aplicacionesThis research focused on the nanosecond(Nd:YAG-1064 nm) laser pulse effect on the optical and morphological properties of chemically modified multi-walled carbon nanotubes(MWCNT).Two sus- pensions of MWCNT in tetrahydrofuran (THF) were prepared,one was submitted to laser pulses for 10 min while the other (blank) was only mechanically homogenized during the same time. Following the laser irradiation, the suspension acquired a yellow-amber color,in contrast to the black translucent appearance of the blank. UV-vis spectroscopy confirmed this observation, showing the blank a higher absorption. Additionally, photoluminescence measurements exhibited a broad blue-green emission band both in the blank and irradiated suspension when excited at 369 nm, showing the blank a lower intensity. However, a modification in the excitation wave length produced a violet to green tuningin the irradiated suspension, which did not occurin the blank. Lastly, the electron microscopy analysis of the treated nanotubes showed the abundant formation of amorphous carbon, nanocages, and nanotube unzipping, exhibiting the intense surface modification produced by the laser pulse. Nanotube surface modification and the coexistence with the new carbon nanostructures were considered as the conductive conditions for optical properties modification.PROME

Synthesis and Characterization of Polyaniline/Magnetite Nanocomposite

trabajo de investigación de Red TemáticaA conducting-electroactive polyaniline/magnetite (PAni/Fe304) nanocomposite was synthesized using anilinium dodecylbenzene sulfonate (S1) as a reactive surfactant. First, S1 allowed magnetite dispersion in the aqueous phase and second, S1 performed as the monomer of polyaniline emeraldine base salt. Electron microscopy suggested core-shell morphology based on S1 amphiphilic character; that is, S1 adsorbed onto the magnetite nanoparticles surface and then was polymerized via an oxidative polymerization forming the shell. The PAni/Fe304 composite exhibited improved thermal stability regarding pure PAni, which was related to the strong interaction between PAni and magnetite. Electrical conductivity, determined by the four-probe method, was in the order of 10-1 and 10-3 S cm-1, respectively, for the pure PAni and the composite. Concerning composite magnetic properties, the decrement in magnetization (σr) and hysteresis (Hc) was attributed to the increment in dipolar magnetic interaction due to the increased separation among magnetite nanoparticles because of the PAni shell.PROMEP-SEP, Programa: Redes Temáticas de Colaboración Académica, "Red de Compuestos Poliméricos, Propiedades y Aplicacione

Role of the vaccum pressure and temperature in the shape of metal Zn nanoparticles

Artículo especializado en revista indexadaZinc (Zn) nanoparticles were fabricated by the high-vacuum thermal evapouration technique. The vacuum pressure was modified from 10−6 to 15 Torr and the substrate temperature was increased from room temperature to 100◦C in order to evaluate the changes in the morphological and structural characteristics of the Zn nanoparticles. Well-faceted hexagonal disk shaped nanoparticles were formed at a vacuum pressure of 10−6 Torr with the substrate kept at room temperature. Aggregation and surface irregularities at the edges of the hexagonal nanodisks were observed with further increases in the vacuum pressure. The nanoscale characteristics of the nanodisks were lost at a vacuum pressure of 10−6 Torr and heating the substrate at 100◦C. The nanodisks were transformed into Zn wires at a vacuum pressure of 15 Torr with a substrate temperature of 100◦C. It is suggested that the initial stages of the growth of the Zn wires are governed by the agglomeration of the Zn nanodisks since the structure of the wires was observed to be composed by stacked nanodisks.CONACYT and PRODEP proyecto de red 2014-201

Maternal outcomes and risk factors for COVID-19 severity among pregnant women.

Pregnant women may be at higher risk of severe complications associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may lead to obstetrical complications. We performed a case control study comparing pregnant women with severe coronavirus disease 19 (cases) to pregnant women with a milder form (controls) enrolled in the COVI-Preg international registry cohort between March 24 and July 26, 2020. Risk factors for severity, obstetrical and immediate neonatal outcomes were assessed. A total of 926 pregnant women with a positive test for SARS-CoV-2 were included, among which 92 (9.9%) presented with severe COVID-19 disease. Risk factors for severe maternal outcomes were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. Pregnant women with severe maternal outcomes were at higher risk of caesarean section [70.7% (n = 53/75)], preterm delivery [62.7% (n = 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n = 31/75)]. In this study, several risk factors for developing severe complications of SARS-CoV-2 infection among pregnant women were identified including pulmonary comorbidities, hypertensive disorders and diabetes. Obstetrical and neonatal outcomes appear to be influenced by the severity of maternal disease

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Modalidad auxiliar de investigación: Acta de Evaluación de trabajo de grado en modalidad auxiliar de investigación, para obtener el título de Doctor en Cirugía Dental, en el proyecto titulado “Impacto en la calidad de vida relacionado a enfermedad periodontal en usuarios que asisten a las Unidades Comunitarias de Salud Familiar en el año 2022”

Acta finalización de proceso de grado de cincuenta estudiantes, quienes finalizaron su trabajo de investigación durante periodo de enero 2022 a diciembre 2022, lo que justifica finalización de requisito en Modalidad Auxiliar de investigación del proyecto del Centro de Investigaciones de la Facultad de Odontología de la Universidad de El Salvador, titulado: “Impacto en la calidad de vida relacionado a enfermedad periodontal en usuarios que asisten a las Unidades Comunitarias de Salud Familiar en el año 2022” para obtener el título de Doctor en Cirugía Dental de la Facultad de Odontología de la universidad de el salvador. Por tanto, se da por finalizado su trabajo de grado en modalidad auxiliar de investigación, el día trece de febrero de dos mil veintitrés

Paisaje Cultural Urbano e Identitad Territorial

Linguaggio contemporaneo e preesistenze: dialogo in un mondo globalizzato Il tema del rapporto con l’antico trova una giusta dimensione operativa quando, superando la sfera delle ideologie e quella delle opposte ragioni della memoria e dello sviluppo, indirizza positivamente l’azione progettuale ora per differenza ora per empatia, a seconda delle circostanze, ma crea sempre una forte tensione tra le ragioni dell’esistente e le necessità del nuovo. Intervenire nell’antico e per l’antico significa, pertanto, riprogettare il nostro modo di relazionarci con il passato, rinegoziandone identità e valori alla luce del nostro presente. Da questa angolazione il patrimonio non è solo lo spazio della memoria o quello della storia, ma diviene lo spazio del desiderio che trae alimento dal mito dell’araba fenice: esso, come principio evolutivo, rappresenta l’inizio di un incessante ricominciamento e l'occasione per una mediazione tra globale e locale