In vivo testing of gold nanoparticles using the Caenorhabditis elegans model organism

Gold nanoparticles (AuNPs) are present in many man-made products and cosmetics, and are also used by the food and medical industries. Tight regulations regarding the use of mammalian animals for product testing can hamper the study of the specific interactions between engineered nanoparticles and biological systems. Invertebrate models, such as the nematode Caenorhabditis elegans (C. elegans), can offer alternative approaches during the early phases of nanoparticle discovery. Here, we thoroughly evaluated the biodistribution of 11-nm and 150-nm citrate-capped AuNPs in the model organism C. elegans at multiple scales, moving from micrometric to nanometric resolution and from the organismal to cellular level. We confirmed that the nanoparticles were not able to cross the intestinal and dermal barriers. We investigated the effect of AuNPs on the survival and reproductive performance of C. elegans, and correlated these effects with the uptake of AuNPs in terms of their number, surface area, and metal mass. In general, exposure to 11-nm AuNPs resulted in a higher toxicity than the larger 150-nm AuNPs. NP aggregation inside C. elegans was determined using absorbance microspectroscopy, which allowed the plasmonic properties of AuNPs to be correlated with their confinement inside the intestinal lumen, where anatomical traits, acidic pH and the presence of biomolecules play an essential role on NP aggregation. Finally, quantitative PCR of selected molecular markers indicated that exposure to AuNPs did not significantly affect endocytosis and intestinal barrier integrity. Statement of significance This work highlights how the simple, yet information-rich, animal model C. elegans is ideally suited for preliminary screening of nanoparticles or chemicals mitigating most of the difficulties associated with mammalian animal models, namely the ethical issues, the high cost, and time constraints. This is of particular relevance to the cosmetic, food, and pharmaceutical industries, which all have to justify the use of animals, especially during the discovery, development and initial screening phases. This work provides a detailed and thorough analysis of 11-nm and 150-nm AuNPs at multiple levels of organization (the whole organism, organs, tissues, cells and molecules).Peer ReviewedPostprint (author's final draft

Latino and Non-Latino Perceptions of the Air Quality in California's San Joaquin Valley.

The San Joaquin Valley (SJV) of California has poor air quality, high rates of asthma, and high rates of obesity. Informational campaigns aimed at increasing awareness of the health impacts of poor air quality and promoting behavior change need to be tailored to the specific target audiences. The study examined perceptions of air quality, perceived health impacts, and methods of accessing information about air quality between Latinos and other groups in the SJV. Residents of the SJV (n = 744) where surveyed via one of three methods: community organizations (256), public locations (251), and an internet panel (237). The results suggest that people perceive the air quality in their region to be generally unhealthy, particularly for sensitive groups. The air quality is more likely to be reported as being unhealthy by people with health problems and less unhealthy by Latinos and people who report regularly exercising. Latinos are more likely to report working outdoors regularly, but also more likely to report being able to reduce their exposure if the air quality is unhealthy. The results report differences in informational sources about air quality, suggesting that informational campaigns should target high risk groups using a variety of media

Multiscaling properties on sequences of turbulent plumes images

A multifractal analysis on a finite-range-scale of the plume concentration images at different experimental conditions (the height of the source Ho), where the measure is the grey value of the image (from 0 to 255), was applied to study its structure through time. The multifractal spectrum showed the characteristic inverse U-shape and a similar evolution in all Ho. The variation of the Hölder exponent (¿a) presented different amplitudes at different moments and increased with time. The symmetry of the spectrum (¿f) decreased with time achieving negative values (from left hand asymmetry evolving to right asymmetry). We show the different behaviour of axial velocity (W) with ¿a and ¿f. There is a linear relation of entrainment coefficient (ae) and the entropy dimension (a1). Therefore, the multifractal spectrum and the derived parameters can be used as markers of plume evolution as well as to study the effect of experimental conditions.Postprint (published version

Understanding Public Views about Air Quality and Air Pollution Sources in the San Joaquin Valley, California.

The San Joaquin Valley of California has poor air quality and high rates of asthma. Surveys were collected from 744 residents of the San Joaquin Valley from November 2014 to January 2015 to examine the public's views about air quality. The results of this study suggest that participants exposed to high PM2.5 (particulate matter less than 2.5 microns in size) concentrations perceived air pollution to be of the worst quality. Air quality in the San Joaquin Valley was primarily perceived as either moderate or unhealthy for sensitive groups. Females perceived air pollution to be of worse quality compared to males. Participants perceived unemployment, crime, and obesity to be the top three most serious community problems in the San Joaquin Valley. Participants viewed cars and trucks, windblown dust, and factories as the principle contributors to air pollution in the area. There is a need to continue studying public perceptions of air quality in the San Joaquin Valley with a more robust survey with more participants over several years and seasons

Consumers’ perceptions, emotional values and the willingness to pay towards luxury wine in Catalonia

To face the increasingly saturated wine market in Spain, the small and medium-sized enterprises are taking advantage of the continuous increasing of the consumption of the high quality wines as a market diversification strategy. An interesting segment that can generate more value added is the positioning on a premium wine and/or luxury wine segment, which is highlighted as a differentiation marketing strategy. In this context, the aim of this study is to analyze consumers’ personal values, perceptions, motivations and the willingness to pay for luxury wines in Catalonia. For the data collection, 157 wine consumers were surveyed in Barcelona province. Results show greater preference for organic and/or sustainable wines.Postprint (published version

Revisiting pseudo-Dirac neutrinos

We study the pseudo-Dirac mixing of left and right-handed neutrinos in the case where the Majorana masses M_L and M_R are small when compared with the Dirac mass, M_D. The light Majorana masses could be generated by a non-renormalizable operator reflecting effects of new physics at some high energy scale. In this context, we obtain a simple model independent closed bound for M_D. A phenomenologically consistent scenario is achieved with M_L,M_R ~ 10^{-7} eV and M_D ~ 10^{-5}-10^{-4} eV. This precludes the possibility of positive mass searches in the planned future experiments like GENIUS or in tritium decay experiments. If on the other hand, GENIUS does observe a positive signal for a Majorana mass \geq 10^{-3} eV, then with very little fine tuning of neutrino parameters, the scale of new physics could be in the TeV range, but pseudo-Dirac scenario in that case is excluded. We briefly discuss the constraints from cosmology when a fraction of the dark matter is composed of nearly degenerate neutrinos.Comment: 17 pages, no figures, references added, to be published in PL

‘E-TAP’ CURRICULUM FOR VIRTUE EDUCATION: A FIT ANALYSIS TO THE ‘SKOLA-2030’ CURRICULUM

The virtue education curriculum ‘e-TAP’ is one of the recent efforts for improving character and virtue education at school in Latvia from preschool till grade nine. The objective of this research was to provide evidence regarding whether this curriculum is appropriate (‘fits’) to the Latvian context, in particular in reference to the Skola-2030 curriculum. Based on fit and feasibility theory, this work addressed the research question: “How does the treatment of virtues of the e-TAP curriculum fit to the treatment of virtues of the new Skola-2030 curriculum?”. The analysis used statistical descriptive frequency analysis of the virtues of each programme and comparative analysis between the two document sets included in each of them, using Excel software. The results show that Skola-2030 programme stresses performance and civic virtues, while the e-TAP programme underlines moral and intellectual virtues. Performance virtues are the most important ones in Skola-2030 (38 %), but account only for 17 % in the e-TAP curriculum. In addition, in Skola-2030 curriculum civic virtues account for 23 %, while in e-TAP they are only 8 %. In the e-TAP curriculum, moral virtues account for half of all the mentions (50 %) and intellectual virtues for 25 %, whereas in Skola-2030 those virtue groups account for 22 % and 18 %, respectively. The high ‘complementarity fit’ of both programmes suggests that the e-TAP curriculum could considerably enrich the Skola-2030 educational offer. Suggestions for e-TAP programme improvement and further research are put forward.

Particle-in-cell simulations of Alfv\'en wave parametric decay in a low-beta plasma

We study the parametric decay instability of parallel propagating Alfv\'en wave in a low-beta plasma using one-dimensional fully kinetic simulations. We focus for the first time on the conversion of the energy stored in the initial Alfv\'en wave into particle internal energy, and on its partition between particle species. We show that compressible fluctuations generated by the decay of the pump wave into a secondary ion-acoustic mode and a reflected Alfv\'en wave contribute to the gain of internal energy via two distinct mechanisms. First, the ion-acoustic mode leads nonlinearly to proton trapping and proton phase space mixing, in agreement with previous work based on hybrid simulations. Second, during the nonlinear stage, a compressible front of the fast type develops at the steepened edge of the backward Alfv\'en wave leading to a field-aligned proton beam propagating backwards at the Alfv\'en speed. We find that parametric decay heats preferentially protons, which gain about 50% of the pump wave energy in the form of internal energy. However, we find that electrons are also energized and that they contribute to the total energy balance by gaining 10% of the pump wave energy. By investigating energy partition and particle heating during parametric decay, our results contribute to determine the role of compressible and kinetic effects in wave-driven models of the solar wind

Electrospinsters Final Project Report

An electrospinning machine (EM) produces fibers and particles by means of applying a voltage process (electrohydrodynamic phenomena) to a polymer solution by incorporating the use of a receptacle, a pump, a high voltage power supply (HVPS) and a collector. EMs are typically very expensive, however, there has been work conducted by various researchers to construct in-house machines at a much lower cost. The growing applications for electrospinning continue to be a source of interest for many researchers as it is still a relatively new process. Much of the effort has been dedicated to producing nanofibers with unique properties with a focus on improving the efficiency and scalability of the process. The Electrospinsters Senior Design Team are researching and designing an in-house EM that can produce nanofibers for the team sponsor’s research and serve other educational purposes at Trinity University. The sponsor, Dr. Dany Munoz-Pinto, intends to use the results of this project to expand his research projects and goals by incorporating nanofibers into tissue scaffolds. The prototype must be a functioning EM so that a future team or the sponsor’s research students can make additions, but not struggle with the basic functions to create nanofibers. Based on published literature and additional research conducted by the team, we determined that an EM is composed of four subsystems: a syringe pump, a HVPS, a collector, and a user interface. The HVPS provides a voltage to the solution in the syringe pump which when exuded is drawn to the grounded collector due to the difference in electric potential. This drawn-out solution conglomerates on the collector which forms the scaffold. Published literature allowed us to gain a better understanding of the setup and we learned that there is not much variation in how the EM can be modified. Consequently, we chose to follow a fundamental setup with a flat collector plate due to its easy construction and compatibility with producing non-woven nanofibers with polyvinyl alcohol (PVA). We designed and conducted a series of tests to validate the subsystems of the device and to test the EM against various design constraints and project requirements. Some of our constraints pertained to time and budget and our project met both of these, as we successfully created a working prototype for our sponsor by the end of the 2023 spring semester, and we only used $808.92 of our$1200 budget. Other criteria related to health and safety were met, since we complied with TU Environmental Health and Safety and OSHA standards, the voltage applied to the solution did not exceed 30 kV at any point during testing and application, and our device fit dimensional constraints and was only operated in a CSI fume hood to prevent the inhalation of nanoparticles. Our prototype operates all electrical subsystems using US standard outlets. Certain requirements correlated with certain subsystems which had specific tests designed to evaluate the flow rate, voltage, voltage display, and nanofiber diameter. The Flow Rate Variability Test evaluated the syringe pump subsystem with variable flow rates of 0.5 mL/hr, 1.0 mL/hr, and 1.5 mL/hr and deemed accurate enough for testing purposes. The Voltage Variability Test tested the active voltage of the HVPS and verified its operation is within a ±5% margin of error. The Proof-of-Concept Test verified that the EM could produce non-woven nanofibers of 200 nm and that it is within ±20% error of previously published experiments, which are acceptable results for our sponsor’s research purposes. Additionally, we tested Tip Diameter Variability and Collection Distance Variability to observe the effects on the nanofiber diameter and determined that there is not a significant difference as they are still within ±20% error, as we had expected from published literature. Overall, the Electrospinsters created a successful, working prototype to aid in our sponsor’s research. Our prototype met all requirements and constraints, and there are no remaining changes needed to achieve our final goals. However, for further improvements, we hope that a future team will improve this final prototype by integrating another type of collector that can produce aligned nanofibers while maintaining the ability to interchange collector types and implementing any other useful additions or modifications