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The article discusses the measurement of the magnetic field produced by a linear octupole formed by four magnets, focusing on the x-component's dependence on distance. Using a smartphone app with a magnetic sensor, the experiment aims to compare experimental results with theoretical predictions of a quintic decrease in the magnetic field. The study successfully demonstrates the expected quintic behavior, with the experimental value of the exponent closely matching the theoretical value. The research findings suggest that this experiment could be valuable for first-year STEM students, emphasizing the effectiveness of hands-on laboratory work in facilitating meaningful learning experiences. [Extracted from the article]

We believe that a natural focus of the physics education research community is on understanding and improving students' learning in our physics courses. Due to the increase in technology, we can bring laboratory experiments closer to our students. It is necessary to update our laboratories technologically to get closer to the world in which our students live. With this in mind, we have considered the magnetic field created by a linear quadrupole and we have studied its dependence on distance, n being the exponent of distance. The main objective of this exercise is for our students to discover that the exponent n is very close to –4. The purpose of this work is to show that a laboratory is a powerful tool that increases significant learning under three conditions: 1) the practice must not be too sophisticated; 2) students must handle objects in the lab; and 3) the practice must be scientifically accurate, including the fitting using the least-squares approximation, and the following and necessary error calculation. We provide this practice so that all interested physics teachers can use it and adapt it to their specific laboratory. [ABSTRACT FROM AUTHOR]

The growth of titanium oxide nanoparticles on reconstructed Au(111) was investigated by scanning tunneling microscopy and x-ray photoelectron spectroscopy. Ti was deposited by physical-vapor deposition at 300 K. Regular arrays of titanium nanoparticles form by preferential nucleation of Ti at the elbow sites of the herringbone reconstruction. The titanium oxide nanoclusters were synthesized by subsequent exposure to O2 at 300 K. Two-and three-dimensional titanium oxide nanocrystallites form during annealing in the temperature range from 600 to 900 K. At the same time, the Au(111) surface assumes a serrated <110>-oriented step-edge morphology suggesting step-edge pinning by titanium oxide nanoparticles. The oxidation state of the titanium oxide nanoparticles varies with annealing temperature. Specifically, annealing to 900 K results in the formation of stoichiometric TiO2 nanocrystals as judged by the Ti(2p) binding energies measured in the x-ray photoelectron data. The nanodispersed TiO2 on Au(111) is an ideal system to test the various models proposed for the enhanced catalytic reactivity of supported Au nanoparticles. [ABSTRACT FROM AUTHOR]

Simultaneously with the increase of Radiofrequency Electromagnetic Fields (RF-EMF) in recent decades, there has been increasing concern about their potential relation with the etiology of several tumors. At this time, the techniques of spatial data analysis jointly with the study of the personal exposure to these fields offer a new approach to the problem. This paper presents the results of a preliminary epidemiological study, combining Epidemiology, Statistics and Geographical Information Systems (GIS), in which we analyzed the correlation between exposure to RF-EMF in the city of Albacete (166,000 inhabitants, southeast Spain) and the incidence of several cancers with unspecific causes (lymphomas, and brain tumors). We used statistical tools to analyze the spatial point patterns and aggregate data with the aim to study the spatial randomness and to determine the zones with the highest incidence from 95 tumors studied (65 lymphomas, 12 gliomas and 18 meningiomas). We also perform a correlation (Spearman) study between the personal exposure to RF-EMF in 14 frequency bands, recorded by an EME Spy 140 (Satimo) exposimeter in the city's administrative regions, and the incidence of the tumors registered from January 2012 to May 2015. The studied cancer cases have a random spatial distribution inside the city. On the other hand, and by means of an ecological study, we verified that the exposure to RF-EMF registered in the city of Albacete shows little correlation with the incidence of the studied tumors (gliomas (ρ = 0.15), meningiomas (ρ = 0.19) and lymphomas (ρ = − 0.03)). The proposed methodology inaugurates an unexplored analysis path in this field. [ABSTRACT FROM AUTHOR]

Abstract: The reactivity of methanol on TiO2 nanoparticles supported on Au(111) was examined using temperature-programmed reaction spectroscopy. Since quantitative analytical techniques have shown that the nanoparticles formed by oxidation of sputtered Ti metal on Au(111) have TiO2 stoichiometry, the reactivity of these particles towards methanol was compared to the reactivity of TiO2(110), the most thermodynamically stable single crystal surface. The reactivity of the nanoparticles differed from that of the TiO2(110) stoichiometric surface. Specifically, the nanoparticles produced methane from methanol while the TiO2(110) stoichiometric surface did not. This difference is attributed to under-coordinated titanium cations present on facets of the nanoparticles, such as those found on {011}-facetted TiO2(001) planes, which lead to methane formation. The differences in reactivity towards methanol between the nanoparticles and the extended TiO2(110) stoichiometric surfaces suggest that the three-dimensional, local structure plays a very significant role in the reactivity of these nanoparticles towards methanol. [Copyright &y& Elsevier]

Methanol adsorption on stoichiometric and defective TiO2(1 1 0) surfaces was studied by means of TPRS and XPS. Anion vacancy defects were created by electron bombardment in order to minimize the structural damage inflicted to the surface. Methanol adsorbed dissociatively on the TiO2(1 1 0) surfaces at room temperature, forming methoxide and hydroxide groups. On the stoichiometric surface most methoxide groups recombined at low temperature (320 K) to form methanol, while a small fraction (∼15%) converted to formaldehyde and methanol at high temperature (630 K). On the electron-irradiated (defective) surfaces, a significant fraction of methoxy groups (28–36%) reacted to form methane above 450 K. The activation energy for methane desorption decreased with increasing number of anion vacancy defects. Methane formation from methoxy is favored in the presence of defects because the oxygen released is returned to the surface, healing the anion vacancy defects. Two different binding sites for the methoxy species (Ti4+ cations and anion vacancy defects) are proposed to be responsible for the different reaction products. Oxygen post-dosed after methanol onto the defective surfaces results in the formation of methanol and formaldehyde at high temperature, as on the stoichiometric surface. [Copyright &y& Elsevier]

In recent years, radiofrequency electromagnetic fields (RF-EMF) exposure has increased owing to new communication technologies. Simultaneously, increased exposure to RF-EMF has led to society's growing concern about the possible effects they may have on human health. Many studies have described personal RF-EMF exposure by using personal exposimeters to know a population's daily exposure to mobile phone base stations and to other sources whose installations tend to be permanent. Nonetheless during special events like concerts or fairs, where many people gather, permanent installations might not suffice to cover demand. So telephone companies install temporary stations for these events, and modify the exposure pattern of these areas or populations. To study if installing temporary antennae for large events, and high concentrations of mobile phones, modify the exposure pattern compared to usual situations. Personal RF-EMF exposure from mobile phones (uplink) and mobile phone base stations (downlink) installed at the 2017 Albacete Fair (Spain) was recorded. Between 7 and 17 September, more than 2,500,000 people visited this Fair. Measurements were taken by two Satimo EME SPY 140 personal exposimeters, placed one each side of a research team member's waist. These exposimeters were programmed to take measurements every 4 s at different time of day; morning, afternoon and night; and in several places, around the Fair Enclosure (zones Ejidos and Paseo) and inside the enclosure (Interior). These measurements were repeated on a weekday, at the weekend and the day after the Fair ended after temporary base stations had been removed. They were also taken for 1 h in all three zones, for each time of day; that is, 9 h were recorded for each study day. The mean RF-EMF recorded exposure from base stations (downlink-DL) on the days the Fair opened (morning, afternoon and night) for the three studied zones was 791.8 μW/m2, while the exposure produced by mobile phones (uplink-UL) was 59.0 μW/m2. These values were 391.2 μW/m2 (DL) and 10.3 μW/m2 (UL) a few days after the event ended. In study zones Ejidos and Paseo, both outside, the highest mean exposure was recorded at the weekend as 1494.1 and 848.1 μW/m2 respectively. For the Interior zone, the mean value recorded during the Fair was 354.8 μW/m2. These values contrast with those recorded in the three zones after the event ended: 556.37 (Ejidos), 144.1 (Paseo); 473.21 μW/m2 (Interior). The fact that the mean exposure recorded at Interior was slightly higher after the Fair could be due to signal shielding by so many people. The reduction in exposure in Paseo after the Fair was outstanding, probably due to the antennae being placed on low towers. Major differences were also found in the RF-EMF exposure from UL. In this case, the weekend values taken during the Fair were between 28.2 μW/m2 at Interior (weekday) and 98.1 μW/m2 at Ejidos (weekend), which dropped to 5.5 at Paseo after the Fair, to 11.7 μW/m2 at Interior and to 13.6 μW/m2 at Ejidos. Installing mobile phone base stations, and a dense public using mobile phones, imply a significant increase in personal RF-EMF exposure compared to that recorded during normal periods in the same area. However, the recorded measurements were below legally established limits. • Telephone companies install temporary base stations during special events. • Temporal base stations modify the exposure pattern of these areas or populations. • Personal RF-EMF exposure at the 2017 Albacete Fair (Spain) was recorded. • A significant increase in personal RF-EMF exposure was determined. • Recorded measurements were below legally established limits. [ABSTRACT FROM AUTHOR]

In the last decades, exposure to radiofrequency electromagnetic fields (RF-EMF) has substantially increased as new wireless technologies have been introduced. Society has become more concerned about the possible effects of RF-EMF on human health in parallel to the increase in their exposure. The appearance of personal exposimeters opens up wide-ranging research possibilities. Despite studies having characterised personal exposure to RF-EMF, part of the population is still worried, to the extent that psychogenic diseases ("nocebo" effect) appear, and patients suffer. It could be interesting to share personal exposure results with the population to better understand and promote public health. The main objective was to characterise personal exposure to environmental RF-EMF in Albacete (166,000 inhabitants, SE Spain), and assess the effect of sharing the results of the study on participants' risk perception. Measurements were taken by a personal Satimo EME SPY 140 exposimeter, which was programmed every 10 s for 24 h. To measure personal exposure to RF-EMF, we worked with 75 volunteers. Their personal exposure, 14 microenvironments in the city, e.g., home, outdoors, work, etc., and possible time differences were analysed. After participating in the study, 35 participants completed a questionnaire about their RF-EMF risk perception, which was also answered by a control sample to compare the results (N = 36). The total average exposure of 14 bands was 37.7 μW/m2, and individual ranges fell between 0.2 μW/m2, recorded in TV4&5, and a maximum of 264.7 μW/m2 in DECT. For Friday, we recorded a mean of 53.9 μW/m2 as opposed to 23.4 μW/m2 obtained on Saturday. The recorded night-time value was 27.5 μW/m2 versus 43.8 μW/m2 recorded in the daytime. The mean personal exposure value also showed differences between weekdays and weekend days, with 39.7 μW/m2 and 26.9 μW/m2, respectively. The main source that contributed to the mean total personal exposure was enhanced cordless telecommunications (DECT) with 50.2%, followed by mobile phones with 18.4% and mobile stations with 11.0% (GSM, DCS and UMTS), while WiFi signals gave 12.5%. In the analysed microenvironments, the mean exposure of homes and workplaces was 34.3 μW/m2 and 55.2 μW/m2, respectively. Outdoors, the mean value was 34.2 μW/m2 and the main sources were DECT, WiFi and mobile phone stations, depending on the place. The risk perception analysis found that 54% of the participants perceived that RF-EMF were less dangerous than before participating in the study, while 43% reported no change in their perceptions. Only 9% of the volunteers who received information about their measurements after the study assessed the possible RF-EMF risk with a value over or equal to 4 (on a scale from 1 to 5) versus 39% of the non-participant controls. We conclude that personal exposure to RF-EMF fell well below the limits recommended by ICNIRP and showed wide temporal and spatial variability. The main exposure sources were DECT, followed by mobile phones and WiFi. Sharing exposure results with participants lowered their risk perception. • RF-EMF exposure was measured in Albacete (Spain) using personal exposimeters. • A description of personal exposure is provided in temporary and spatial terms. • Levels of personal exposure were extremely low compared to regulatory limits. • Volunteers were informed about the results. • Access to the results could help reduce the population's risk perception. [ABSTRACT FROM AUTHOR]

In recent years, numerous epidemiological studies, which deal with the potential effects of mobile phone antennas on health, have almost exclusively focused on their distance to mobile phone base stations. Although it is known that this is not the best approach to the problem, this situation occurs due to the numerous difficulties when determining the personal exposure to the radiofrequency electromagnetic fields (RF-EMF). However, due to the rise of personal exposimeters, the evolution of spatial statistics, the development of geographical information systems and the use of powerful software, new alternatives are available to deal with these epidemiological studies and thus overcome the aforementioned difficulties. Using these tools, this paper presents a lattice map of personal RF-EMF exposure from exterior mobile phone base stations, covering the entire 110 administrative regions in the city of Albacete (Spain). For this purpose, we used a personal exposimeter, Satimo EME Spy 140 model, performing measurements every 4 s The exposimeter was located inside the plastic basket of a bicycle, whose versatility permitted the access to all the zones of the city. Once the exposure map was prepared, its relation with the known antenna locations was studied. The 64 mobile telephone antennas of the city were also georeferenced; the randomness of both variables (exposure and antennas) were studied by means of the Moran's I test. Results showed that the distribution of the antennas follows a grouped pattern (p<0.001), while the distribution of the average exposure values have a random distribution (p=0.618). In addition, we showed two Spearman correlation studies: the first between the average exposure values and the number of mobile telephone antennas per administrative region, and the second, also considering the antennas of the neighbouring regions. No substantial correlation was detected in either of the two cases. This study also reveals the weaknesses of the epidemiological studies, which only take into account the distance to the antennas, which would provide a new approach to the problem. By precisely knowing the resident population of each administrative region of the city, this proves to be highly useful to rely on a prepared aggregate data map based on the mean exposure values to RF-EMF in these sections. The displayed map would permit the execution of more accurate epidemiological studies, since it would be possible to compare the exposure measurements with the incidence data of a disease. [ABSTRACT FROM AUTHOR]

In the paper of Wang et al. ([7]), the authors present the relation between cell viability and the three main exposure parameters (electric intensity ( I Es i ), pulse duration ( I i ), and pulse number ( I N i )) of 9.33 GHz pulsed radiofrequency electromagnetic field (RF-EMP). Though the SAR value is high (the electric field intensity is high), the SA value is not high enough to cause significant temperature raising. We used XFDTD to calculate the inner electrical field intensity, and the specific energy absorption rate (SAR, W/kg) and total specific energy absorption (SA, J/kg) value were also be calculated. [Extracted from the article]

Tetrahydrobiopterin (BH4), methyl-tetrahydropterin (MBH4) and dimethyl-tetrahydropterin (DMBH4) are oxidized by tyrosinase in a process during which the suicide inactivation of tyrosinase may occur. From the kinetic study of this process, (apparent maximum constant for the suicide inactivation), (Michaelis constant for the substrate) and r (number of turnovers that the enzyme makes before the inactivation) can be obtained. From the results obtained, it can be deduced that the velocity of the inactivation governed by () and the potency of the same () follow the order: BH4 > MBH4 > DMBH4. [ABSTRACT FROM AUTHOR]

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. • International, National and Regional exposure limits for RF-EMF. • RF-EMF limits are based on the ALARA (As Low As Reasonably Achievable) Principle. • Maximum exposure limit must be scientific related, not political or in any other way. • New technologies and new smartphones require less intensity than previous models. [ABSTRACT FROM AUTHOR]

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. • Review according to PRISMA guidelines and the PECO methodology. • Measurement of personal exposure to RF-EMF with personal exposimeters or other devices. • Exposure levels are considerably lower than the ICNIRP reference values. [ABSTRACT FROM AUTHOR]

This paper presents the discussion of a more complete definition of the fractional modification of an monocyclic enzyme cascade suggested, but not discussed, by Varon et al. (Bull Math Biol 68(7):1461-1493, ) as the quotient of the sum of all forms of the modified protein, i.e. the free one and the intermediate complex converter enzyme of the original protein-modified protein, between the initial concentration of the target protein. From this general equation, obtained under three assumptions necessary to linearize the set of differential equations describing the kinetic of the system, we derive, as particular cases, other simpler expressions, by applying additional simplifying assumptions, which are, therefore, of a smaller range of validity. We discuss the relationships between the kinetic parameters and concentrations needed for the fulfillment of both the necessary and unnecessary assumptions. The goodness of the analysis was tested by using the shape in the steady state of the simulated time progress curves obtained by numerical integration. Seven arbitrarily chosen examples differing in one or more of the values of the concentrations and/or kinetic parameters have been used to support the results. [ABSTRACT FROM AUTHOR]

In this paper we extend to enzyme systems the results previously obtained in paper I of this series for linear compartmental systems. We obtain the time course equations for both the enzyme and ligand species involved in the reaction mechanisms, which fit a general enzyme system model when the connections between the different enzyme species are of first or pseudofirst order. The kinetic equations obtained here for a given species, enzyme or ligand have the advantage over all previous equations described in the literature, in that they are in the most simplified form possible, since they only contain the kinetic parameters and initial concentrations of the enzymatic reaction which really have some influence on the time progress curves of the species under study. These kinetic equations are denominated optimized equation to distinguish them from the others, which shall call non-optimized equations. We discuss those cases when both types of equation coincide and we show how, when they do not coincide, the non-optimized equations can be simplified to the optimized ones. Therefore, we show that the optimized equations could be used in all cases to avoid the need of subsequent simplifications to eliminate the parameters that play no role in the corresponding time equations. To illustrate the use of this procedure we will apply it to two simple examples of enzymatic reactions. [ABSTRACT FROM AUTHOR]

Software application is implemented in this work to take full advantage of the characteristics of current operating systems and to provide the optimized symbolic kinetic equations for both enzyme and ligand species involved in enzyme reactions. This software, called SKEE-w2013, is implemented using C# language and runs under all operating systems from Windows XP up to Windows 8. It is applicable to any enzyme reaction mechanism that fits the general reaction scheme proposed previously by our group. It can be downloaded, free of charge, from . Besides the optimized equations, the software can provide non-optimized equations, so that the user can compare the advantage of using optimized equations rather than the non-optimized ones, whenever they do not coincide. Moreover, the software circumvents the limitations of other existing previous software tools implemented with what are nowadays obsolete programming languages and that, moreover, are limited to non-optimized kinetic equations. [ABSTRACT FROM AUTHOR]

The article focuses on the student peer evaluation as a teaching method in medical students. It says that peer-reviewed model through a personal response system (PRS) increases students' attention and participation and motivates them for better presentations in class. It notes that the system has improved their oral presentations, yet still lacks a global marking system on how students assess their colleagues as well as the absence of an experimental control group.

The study of many biological systems requires the application of a compartmental analysis, together with the use of isotopic tracers, parameter identification and methods to evaluate the mean parameters. For all this, the kinetic equations of the compartmental system as a function of its parameters are needed. In this paper, we present some considerations on the diagrams of connectivity of linear compartmental systems and obtain new properties from the matrix corresponding to the ordinary first-order linear differential equation systems which describe their kinetic behaviour. Using these properties, symbolic equations are obtained in a simplified form. These equations provide the instantaneous amount of substance in any compartment of the system when zero input is injected into one or more of the system compartments, solely as a function of those parameters of compartmental systems which really have an influence on the sought expression. This is unlike what happens in the other symbolic equations obtained in a previous contribution that included all the fractional transfer coefficients involved in the compartmental system, regardless of whether or not they had an influence on the instantaneous amount of substance. [ABSTRACT FROM AUTHOR]

Software has been implemented in this work to take full advantage of the characteristics of current operating systems and to provide the optimized symbolic kinetic equations for the linear compartmental systems derived in part I of this series. This software, called RM-w2011, is implemented using the C# language and runs under Windows XP, Vista and 7. It is applicable to any linear compartmental system, closed or open, and with a zero input in one or more of its compartments. Apart from the optimized equations that the software provides, if so desired, non optimized equations are offered to compare the advantage of using optimized equations while using non optimized ones, whenever they do not coincide. Moreover, the software circumvents the limitations of other previous software tools that operated with non optimized symbolic equations. [ABSTRACT FROM AUTHOR]