Personal exposure to radiofrequency electromagnetic fields: A comparative analysis of international, national, and regional guidelines.

A worldwide overview and analysis for the existing limits of human exposure to Radiofrequency Electromagnetic Fields (RF-EMF) is given in this paper. These reference levels have been established by different national and even regional governments, which can be based on the guidelines provided by the recommendations of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), the International Committee on Electromagnetic Safety of the Institute of Electrical and Electronics Engineers (IEEE), and even in the United States of the Federal Communications Commission (FCC), as well as, are based on the so-called precautionary principle. Explicit reference is made to the exposure limits adopted in countries or regions, such as Canada, Italy, Poland, Switzerland, China, Russia, France, and regions of Belgium (Brussels, Flanders, Wallonia), where the limits are much lower than the international standards. The limits are compared to a selected set of in-situ measurements. This clearly shows that the measured values are typically very small compared to the international standards but could be somewhat higher compared to the reduced limits. Based on this observation and the reasonable assumption that the sensitivity of people to Electromagnetic Fields (EMF) is the same everywhere (whole-body), we propose the idea to establish a worldwide reference limit for the general public, thus applicable in all countries, if the ICNIRP considers it appropriate. Research must continue to generate measurement data that demonstrate the levels of exposure to which we are really exposed, and with this, provide arguments to the organizations that established the guidelines, especially the ICNIRP, to evaluate whether the current limits are too much. High and can be modified when considered pertinent. To the best of our knowledge, at no time has the reference level for the general public been exceeded.

Fontan surgery failure: risk factors and experience in a Colombian reference centre.

BACKGROUND: The Fontan procedure is considered one of the most remarkable achievements in paediatric cardiology and cardiac surgery. Its final anatomical objective is a venous return through the superior and inferior vena cava. The complications inherent to this procedure and subsequent failure are its limitations. OBJECTIVE: To describe the clinical and haemodynamic characteristics of patients with Fontan failure and define the risk factors associated with it, with its short- and long-term outcomes during a 21-year observation period. METHODS: This is a retrospective follow-up study in which 15 patients diagnosed with Fontan failure in the single-ventricle programme of a high-complexity hospital in Medellín, Colombia, between 2001 and 2022 were included. RESULTS: One hundred and eight patients were identified in whom the Fontan procedure was performed, and 17 met the failure criteria. 82.4% were men, with a median age of 4.3 years. Ebstein's anomaly was the most common diagnosis, 29.4%. All patients underwent Fontan with an extracardiac tube following the procedure. According to the type of failure, 58.8% of patients presented protein-losing enteropathy and 17.6% plastic bronchitis. During follow-up, 5.9% of patients died. CONCLUSION: Fontan surgery in our centre is an option for patients with univentricular physiology. The correct selection of the patient is essential to mitigate failure risks.

Measurement studies of personal exposure to radiofrequency electromagnetic fields: A systematic review.

The last 25 years have seen an increase in the number of radiofrequency sources with the global adoption of smartphones as primary connectivity devices. The objective of this work was to review and evaluate the measured studies of personal exposure to Radiofrequency Electromagnetic Fields (RF-RMF) and meet the basic quality criteria eligible for inclusion in this Review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, following the eligibility criteria of the PECO (Population, Exposure, Comparator, and Outcome) methodology, and the instrument for critical reading Critical Appraisal Skills Programme Español (CASPe). We systematically reviewed the works published between January 1, 1998, and December 31, 2021, yielding 56 publications. Of the different types of studies in which personal exposure to RF-EMF has been measured with two measurement methodologies can be highlighted: Personal measurements with volunteers and Personal measurements with a trained researcher (touring a specific area, one or several microenvironments, an entire city, walking or in some means of transport). Personal exposimeters were used in 83% of the studies. The lowest mean was measured in Egypt with a value of 0.00100 µW/m2 (1.00 nW/m2) in 2007 and the highest mean was measured in Belgium with a value of 285000 µW/m2 (0.285 W/m2) in 2019. The results of our study confirm that RF-EMF exposure levels are well below the maximum levels established by the ICNIRP guidelines.

Positively charged nanofiltration membrane synthesis, transport models, and lanthanides separation.

The design and understanding of rejection mechanisms for both positively and negatively charged nanofiltration (NF) membranes are needed for the development of highly selective separation of multivalent ions. In this study, positively charged nanofiltration membranes were created via an addition of commercially available polyallylamine hydrochloride (PAH) by conventional interfacial polymerization technique. Demonstration of real increase in surface zeta potential, along with other characterization methods, confirmed the addition of weak basic functional groups from PAH. Both positively and negatively charged NF membranes were tested for evaluating their potential as a technology for the recovery or separation of lanthanide cations (neodymium and lanthanum chloride as model salts) from aqueous sources. Particularly, the NF membranes with added PAH performed high and stable lanthanides retentions, with values around 99.3% in mixtures with high ionic strength (100 mM, equivalent to ~6,000 ppm), 99.3% rejection at 85% water recovery (and high Na+/La3+ selectivity, with 0% Na+ rejection starting at 65% recovery), and both constant lanthanum rejection and permeate flux at even pH 2.7. Donnan steric pore model with dielectric exclusion elucidated the transport mechanism of lanthanides and sodium, proving the potential of high selective separation at low permeate fluxes using positively charged NF membranes.

Successful endovascular treatment of aortic arch aneurysm in a pediatric patient.

BACKGROUND: Ascending aortic aneurysms are rare pathologies in childhood, especially in the absence of previous diseases such as Marfan syndrome. OBJECTIVE: Present the possibility of successful endovascular management of large vessel aneurysms, using stents and microcatheters with embolization of the aneurysm sac. METHOD: We present the case of a previously healthy ten-year-old patient, in whom a pseudoaneurysm was documented between the origin of the left common carotid artery and left subclavian artery, successfully managed endovascularly, initially with a stent covering the neck of the aneurysm to remodel it and later with embolization of the aneurysm sac using a microcatheter. RESULTS: Aneurysms of large vessels, such common carotid artery and subclavian artery, are at risk of rupture with devastating complications; endovascular management is considered a minimally invasive management option, with favorable results. CONCLUSION: The endovascular management of large vessel aneurysms using stents and microcatheters with embolization of the aneurysmal sac is a novel management option that achieves successful results.

ANTECEDENTES: Los aneurismas de la aorta ascendente son patologías poco frecuentes en la infancia, sobre todo en ausencia de enfermedades previas como el síndrome de Marfan. OBJETIVO: Dar a conocer la posibilidad del manejo endovascular exitoso de los aneurismas de grandes vasos, usando stent y micro catéter con embolización del saco aneurismático. MÉTODO: Presentamos el caso de una paciente de 10 años y 2 meses, previamente sana, en quien se documentó un pseudoaneurisma entre el origen de la arteria carótida común izquierda y la arteria subclavia izquierda, que logró manejarse de forma endovascular, inicialmente con un stent cubriendo el cuello del aneurisma con el fin de remodelarlo y posteriormente por medio de microcatéter se realizó embolización del saco del aneurisma con coils, con resultado exitoso. RESULTADOS: Los aneurismas de los grandes vasos, como la arteria carótida común y la arteria subclavia, tienen riesgo de ruptura con complicaciones devastadoras; el manejo endovascular se plantea como una opción poco invasiva de manejo, con resultados favorables. CONCLUSIÓN: El manejo de aneurismas de grandes vasos, por vía endovascular usando stent y microcatéter con embolización del saco aneurismático, es una opción novedosa de manejo que logra resultados exitosos.

[Tratamiento endovascular exitoso de aneurisma del ventrículo izquierdo en un paciente pediátrico].

BACKGROUND: Aneurysms and diverticula of the left ventricle are rare entities in childhood, with a prevalence of less than 0.1%. Described since 1886, as a severe and potentially fatal disease if not corrected, mainly due to the presence of associated anomalies and the risk of rupture. OBJETIVE: Present other management options for ventricular diverticula, different from surgical options, using alternative materials that are not used very often in daily practice. METHOD: A detailed description of a case successfully managed with these new treatment modalities. RESULTS: Endovascular management of the left ventricular diverticulum, diagnosed prenatally in the patient presented, was successful after initial failure with surgical management. CONCLUSIONS: Endovascular management of ventricular diverticula, using alternative materials to those commonly used, is an attractive option with satisfactory results in these patients.

Interatrial Septum Stenting for Hypoplastic Left Heart Syndrome in Ex Utero Intrapartum Therapy.

Patients with hypoplastic left heart syndrome (HLHS) with intact atrial septum have an increased mortality rate. This presentation occurs in 6% to 10% of cases. We present a patient with fetal diagnosis of HLHS with restrictive atrial septum. We performed a cesarean section at 37 weeks of gestation, and under ex utero intrapartum treatment proceeded with a median sternotomy and transatrial stenting for left atrial decompression due to findings of intact atrial septum on the fetal echocardiogram performed during the procedure. Subsequently, the patient underwent hybrid stage I palliation followed by a comprehensive stage II procedure at five months of age, but unfortunately died from postoperative complications.

Effects of the Applied Potential on the Performance of Polysulfone Membranes Functionalized with Sulfonated Polyether Ether Ketone Polymers.

The global water crisis growth has led to a tremendous increase in membrane technology research. Membranes are favored over many other technologies for water treatment because, in principle, they require no chemical additives and can be used isothermally at low temperatures. Membranes that can reject contaminants and salts, produce adequate permeate flux values, and require minimal cleaning are highly demanded. However, most synthesized membranes on the market have associated problems, such as membrane fouling; inverse relationships between flux and solute rejection; and the high cost of synthesis, operation, and maintenance. Therefore, there is a continuied need to produce membranes with properties that make them able to sustain flux and selectivity over time. This research study focused on increasing the surface charge and hydrophilicity of polysulfone (PSf) membranes by incorporating sulfonate-functionalized poly-ether-ether-ketone (SPEEK) into PSf/N-Methyl-2-pyrrolidone (PSf/NMP) membranes. The sulfonation of the PEEK provided a net increase in negative charge on the surface of the membranes that enabled charge repulsion to take place, thus increasing the rejection of ions. In this project, the effect of the applied potential on the performance of SPEEK: PSf/NMP membranes was evaluated. The characterization of the as-synthesized membranes was carried out using the surface's structure and morphology, contact angle, and zeta potential. Furthermore, a voltage of 1.5 V was applied to the membranes in the presence of various salts (sodium chloride, calcium chloride, and potassium chloride salts) to evaluate the effects of the applied potential on solute rejection. It was found that both the permeability and the selectivity of the membranes increased when the voltage was applied. The obtained results indicate that incorporating SPEEK into PSf/NMP membranes increased the hydrophilicity of the membranes, and under the applied voltage, the incorporation allowed it to function as an electrodialysis process that is capable of removing ions from water bodies by utilizing the charge repulsion of ions.

Comment on Martin L. Pall "Millimeter (MM) wave and microwave frequency radiation produce deeply penetrating effects: the biology and the physics", Rev Environ Health, 2021.

In this letter, we present some comments related to Pall's publication, in which Pall states that the electric field disappears after a few centimeters and that the magnetic field continues progressing within the studied material.

Comparison of personal exposure to Radiofrequency Electromagnetic Fields from Wi-Fi in a Spanish university over three years.

In this work we present the personal exposure levels to Radiofrequency Electromagnetic Fields (RF-EMF) from Wireless Fidelity (Wi-Fi) 2.4 GHz and 5.85 GHz bands in a Spanish university, specifically, at the Faculty of Computer Science Engineering at the University of Castilla-La Mancha (Albacete, Spain). We present results from three years, 2017, 2018 and 2019 in the same study place and points; and measurements carried out in 2022 inside a classroom and inside a professor's office, with the aim to compare the measurements and verify compliance with reference levels established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The minimum average was 0.0900 µW/m2 in the 2.4 GHz Wi-Fi, in 2019, and the maximum average was 211 µW/m2 in the 5.85 GHz Wi-Fi in 2017, around the building. Comparing the measurements carried out inside the classroom with students and without students, we identified that the maximum value was 278 µW/m2 (classroom with students, in the 5.85 GHz Wi-Fi band) and the minimum value was 37.9 µW/m2 (classroom without students, in the 5.85 GHz Wi-Fi band). Finally, comparing the results of all the measurements (average values) inside the classroom and inside a professor's office, the maximum value was 205 µW/m2 (in the 5.85 GHz Wi-Fi band) inside the classroom with students, and the minimum value was 0.217 µW/m2 inside a professor's office (in the 2.4 GHz Wi-Fi band). These values in no case exceed the limits established by the International Commission on Non-Ionizing Radiation Protection, 10 W/m2 for general public exposure.

Personal exposure from free Wi-Fi hotspots in downtown Mexico City.

In 2019, the Government of Mexico City implemented actions that allowed citizens to approach a free Wi-Fi hotspot, where more than 13000 points have been installed throughout the city. In this work, we present the results of the measurements of personal exposure to Radiofrequency Electromagnetic Fields carried out in Plaza de la Constitución, better known as Zócalo located in the center of Mexico City. The measurements were taken by one of the researchers while walking on a weekday morning and afternoon, in different microenvironments (on the street, on public transport: subway, at the Zócalo, and finally, at home). We also carry out spot measurements in the center of the Zócalo. Subsequently, we carried out a comparative analysis of the different microenvironments, through box plot and violin plot, and we elaborate georeferenced and interpolated maps with intensity levels through the Kriging method, using the Geographic Information System. The Kriging interpolation gives us a good visualization of the spatial distribution of RF-EMF exposure in the study area, showing the highest and lowest intensity levels. The mean values recorded at the measured points in the Zócalo were 326 µW/m2 in the 2.4- to 2.5-GHz Wi-Fi band and 2370 µW/m2 in the 5.15- to 5.85-GHz Wi-Fi band. In the case of the mean values recorded on the street, they were 119 µW/m2 in the 2.4- to 2.5-GHz frequency band and 31.8 µW/m2 in the 5.15- to 5.85-GHz frequency band, like the values recorded at home, 122 µW/m2 and 33.9 µW/m2, respectively. All values are well below the reference levels established by the International Commission on Non-Ionizing Radiation Protection.

Microcystin-LR Removal from Water via Enzymatic Linearization and Ultrafiltration.

Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria that can bloom in freshwater supplies. This study describes a new strategy for remediation of MC-LR that combines linearization of the toxin using microcystinase A, MlrA, enzyme with rejection of linearized byproducts using membrane filtration. The MlrA enzyme was expressed in Escherichia coli (E. coli) and purified via a His-tag with 95% purity. Additionally, composite membranes made of 95% polysulfone and 5% sulfonated polyether ether ketone (SPEEK) were fabricated and used to filter a solution containing cyclic and linearized MC-LR. Tests were also performed to measure the adsorption and desorption of MC-LR on polysulfone/SPEEK membranes. Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the progress of linearization and removal of MC-LR. Results indicate that the MlrA was successful at linearizing MC-LR. Membrane filtration tests showed rejection of 97% of cyclic MC-LR and virtually all linearized MC-LR, with adsorption to the membranes being the main rejection mechanism. Adsorption/desorption tests indicated that methanol could be used to strip residual MC-LR from membranes to regenerate them. This study demonstrates a novel strategy of remediation of microcystin-tainted water, combining linearization of MC-LR to a low-toxicity byproduct along with removal by membrane filtration.

Non-Solvent Induced Phase Separation (NIPS) for Fabricating High Filtration Efficiency (FE) Polymeric Membranes for Face Mask and Air Filtration Applications.

Protection against airborne viruses has become very relevant since the outbreak of SARS-CoV-2. Nonwoven face masks along with heating, ventilation, and air conditioning (HVAC) filters have been used extensively to reduce infection rates; however, some of these filter materials provide inadequate protection due to insufficient initial filtration efficiency (FE) and FE decrease with time. Flat sheet porous membranes, which have been used extensively to filter waterborne microbes and particulate matter due to their high FE have the potential to filter air pollutants without compromising its FE over time. Therefore, in this study, single layer polysulfone (PSf) membranes were fabricated via non-solvent induced phase separation (NIPS) and were tested for airflow rate, pressure drop and FE. Polyethylene glycol (PEG) and glycerol were employed as pore-forming agents, and the effect of the primary polymer and pore-forming additive molecular weights (MW) on airflow rate and pressure drop were studied at different concentrations. The thermodynamic stability of dope solutions with different MWs of PSf and PEG in N-methylpyrrolidone (NMP) at different concentrations was determined using cloud-point measurements to construct a ternary phase diagram. Surface composition of the fabricated membranes was characterized using contact angle and X-ray photoelectron spectroscopy (XPS), while membrane morphology was characterized by SEM, and tensile strength experiments were performed to analyze the membrane mechanical strength (MS). It was observed that an increase in PSf and PEG molecular weight and concentration increased airflow and decreased pressure drop. PSf60:PEG20:NMP (15:15:70)% w/w showed the highest air flow rate and lowest pressure drop, but at the expense of the mechanical strength, which was improved significantly by attaching the membrane to a 3D-printed polypropylene support. Lastly, the FE values of the membranes were similar to those of double-layer N95 filters and significantly higher than those of single layer of N95, surgical mask and HVAC (MERV 11) filters.

Epidemiological behavior of suicide attempt in Colombian adolescents years 2016-2019: An ecological study.

OBJECTIVE: characterize the behavior of attempted suicide in adolescents in Colombia, and its associated epidemiological factors from 2016 to 2019. METHOD: quantitative, observational, descriptive, and ecological study. The sample was extracted from the database of the Integrated Social Protection Information System, by identifying cases of attempted suicide for ages in the range from 12 to 17 years old, calculated for a prevalence estimate based on a total population of 32,076. Univariate and bivariate analysis of the variables of interest was performed. RESULTS: suicide attempts occurred more frequently in females (n: 24,619; 76.7%), of subsidized regime (n: 17,960; 56%); and being in psychiatric centers is the most frequent vulnerability condition (n: 676; 2.11%). Living in the capital city is a risk factor for attempted suicide (OR: 1.423; 95% CI: 1.385 to 1.462), while being male is a protective factor (OR: 0.290; 95% CI: 0.283 a 0.298). CONCLUSION: suicide attempts are a subject of interest in Public Health due to their prevalence and impact on the family and social environment. The Nursing professional is competent in the identification, treatment, and prevention of this phenomenon. HIGHLIGHTS: (1) Know the epidemiological behavior of suicide attempt in adolescents.(2) Reflect on nursing care in the approach to suicide attempts.(3) Identify the conditions of vulnerability related to suicide attempts.(4) The methodological design allows reviewing the problem at national level.

Advanced Research and Development of Face Masks and Respirators Pre and Post the Coronavirus Disease 2019 (COVID-19) Pandemic: A Critical Review.

The outbreak of the COVID-19 pandemic, in 2020, has accelerated the need for personal protective equipment (PPE) masks as one of the methods to reduce and/or eliminate transmission of the coronavirus across communities. Despite the availability of different coronavirus vaccines, it is still recommended by the Center of Disease Control and Prevention (CDC), World Health Organization (WHO), and local authorities to apply public safety measures including maintaining social distancing and wearing face masks. This includes individuals who have been fully vaccinated. Remarkable increase in scientific studies, along with manufacturing-related research and development investigations, have been performed in an attempt to provide better PPE solutions during the pandemic. Recent literature has estimated the filtration efficiency (FE) of face masks and respirators shedding the light on specific targeted parameters that investigators can measure, detect, evaluate, and provide reliable data with consistent results. This review showed the variability in testing protocols and FE evaluation methods of different face mask materials and/or brands. In addition to the safety requirements needed to perform aerosol viral filtration tests, one of the main challenges researchers currently face is the inability to simulate or mimic true aerosol filtration scenarios via laboratory experiments, field tests, and in vitro/in vivo investigations. Moreover, the FE through the mask can be influenced by different filtration mechanisms, environmental parameters, filtration material properties, number of layers used, packing density, fiber charge density, fiber diameter, aerosol type and particle size, aerosol face velocity and concentration loadings, and infectious concentrations generated due to different human activities. These parameters are not fully understood and constrain the design, production, efficacy, and efficiency of face masks.

Polymers and Solvents Used in Membrane Fabrication: A Review Focusing on Sustainable Membrane Development.

(1) Different methods have been applied to fabricate polymeric membranes with non-solvent induced phase separation (NIPS) being one of the mostly widely used. In NIPS, a solvent or solvent blend is required to dissolve a polymer or polymer blend. N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF) and other petroleum-derived solvents are commonly used to dissolve some petroleum-based polymers. However, these components may have negative impacts on the environment and human health. Therefore, using greener and less toxic components is of great interest for increasing membrane fabrication sustainability. The chemical structure of membranes is not affected by the use of different solvents, polymers, or by the differences in fabrication scale. On the other hand, membrane pore structures and surface roughness can change due to differences in diffusion rates associated with different solvents/co-solvents diffusing into the non-solvent and with differences in evaporation time. (2) Therefore, in this review, solvents and polymers involved in the manufacturing process of membranes are proposed to be replaced by greener/less toxic alternatives. The methods and feasibility of scaling up green polymeric membrane manufacturing are also examined.

Personal Exposure Assessment to Wi-Fi Radiofrequency Electromagnetic Fields in Mexican Microenvironments.

In recent years, personal exposure to Radiofrequency Electromagnetic Fields (RF-EMF) has substantially increased, and most studies about RF-EMF with volunteers have been developed in Europe. To the best of our knowledge, this is the first study carried out in Mexico with personal exposimeters. The main objective was to measure personal exposure to RF-EMF from Wireless Fidelity or wireless Internet connection (Wi-Fi) frequency bands in Tamazunchale, San Luis Potosi, Mexico, to compare results with maximum levels permitted by international recommendations and to find if there are differences in the microenvironments subject to measurements. The study was conducted with 63 volunteers in different microenvironments: home, workplace, outside, schools, travel, and shopping. The mean minimum values registered were 146.5 µW/m2 in travel from the Wi-Fi 2G band and 116.8 µW/m2 at home from the Wi-Fi 5G band, and the maximum values registered were 499.7 µW/m2 and 264.9 µW/m2 at the workplace for the Wi-Fi 2G band and the Wi-Fi 5G band, respectively. In addition, by time period and type of day, minimum values were registered at nighttime, these values being 129.4 µW/m2 and 93.9 µW/m2, and maximum values were registered in the daytime, these values being 303.1 µW/m2 and 168.3 µW/m2 for the Wi-Fi 2G and Wi-Fi 5G bands, respectively. In no case, values exceeded limits established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Of the study participants (n = 63), a subgroup (n = 35) answered a survey on risk perception. According to these results, the Tamazunchale (Mexico) population is worried about this situation in comparison with several European cities; however, the risk perception changes when they are informed about the results for the study.

Nanohybrid Membrane Synthesis with Phosphorene Nanoparticles: A Study of the Addition, Stability and Toxicity.

Phosphorene is a promising candidate as a membrane material additive because of its inherent photocatalytic properties and electrical conductance which can help reduce fouling and improve membrane properties. The main objective of this study was to characterize structural and morphologic changes arising from the addition of phosphorene to polymeric membranes. Here, phosphorene was physically incorporated into a blend of polysulfone (PSf) and sulfonated poly ether ether ketone (SPEEK) doping solution. Protein and dye rejection studies were carried out to determine the permeability and selectivity of the membranes. Since loss of material additives during filtration processes is a challenge, the stability of phosphorene nanoparticles in different environments was also examined. Furthermore, given that phosphorene is a new material, toxicity studies with a model nematode, Caenorhabditis elegans, were carried out to provide insight into the biocompatibility and safety of phosphorene. Results showed that membranes modified with phosphorene displayed a higher protein rejection, but lower flux values. Phosphorene also led to a 70% reduction in dye fouling after filtration. Additionally, data showed that phosphorene loss was negligible within the membrane matrix irrespective of the pH environment. Phosphorene caused toxicity to nematodes in a free form, while no toxicity was observed for membrane permeates.