3D Printed Polymeric Hydrogels for Nerve Regeneration

The human nervous system lacks an inherent ability to regenerate its components upon damage or diseased conditions. During the last decade, this has motivated the development of a number of strategies for nerve regeneration. However, most of those approaches have not been used in clinical applications till today. For instance, although biomaterial-based scaffolds have been extensively used for nerve reparation, the lack of more customized structures have hampered their use in vivo. This highlight focuses mainly on how 3D bioprinting technology, using polymeric hydrogels as bio-inks, can be used for the development of new nerve guidance channels or devices for peripheral nerve cell regeneration. In this concise contribution, some of the most recent and representative examples are highlighted to discuss the challenges involved in various aspects of 3D bioprinting for nerve cell regeneration, specifically when using polymeric hydrogels

Formal security analysis of registration protocols for interactive systems: a methodology and a case of study

In this work we present and formally analyze CHAT-SRP (CHAos based Tickets-Secure Registration Protocol), a protocol to provide interactive and collaborative platforms with a cryptographically robust solution to classical security issues. Namely, we focus on the secrecy and authenticity properties while keeping a high usability. In this sense, users are forced to blindly trust the system administrators and developers. Moreover, as far as we know, the use of formal methodologies for the verification of security properties of communication protocols isn't yet a common practice. We propose here a methodology to fill this gap, i.e., to analyse both the security of the proposed protocol and the pertinence of the underlying premises. In this concern, we propose the definition and formal evaluation of a protocol for the distribution of digital identities. Once distributed, these identities can be used to verify integrity and source of information. We base our security analysis on tools for automatic verification of security protocols widely accepted by the scientific community, and on the principles they are based upon. In addition, it is assumed perfect cryptographic primitives in order to focus the analysis on the exchange of protocol messages. The main property of our protocol is the incorporation of tickets, created using digests of chaos based nonces (numbers used only once) and users' personal data. Combined with a multichannel authentication scheme with some previous knowledge, these tickets provide security during the whole protocol by univocally linking each registering user with a single request. [..]Comment: 32 pages, 7 figures, 8 listings, 1 tabl

Examining the influence of STEM college program participation on engineering persistence among first-generation college students in engineering

The present study used Social Cognitive Career Theory (SCCT; Lent et al., 1994; Lent et al., 2000) to examine the influence of college STEM (science, technology, engineering, and mathematics) program participation on engineering persistence among first-generation college students (FGCS) in engineering. Data for the present study came from a larger longitudinal study on engineering students that collected data from a quantitative (Qualtrics) survey during Spring 2015 and Spring 2016 across 11 universities in the United States. Participants for this present study were 473 FGCS (73.4 percent Latinx and 26.6. percent White) across different undergraduate class standings pursuing an engineering degree. Participants in the present study were considered FGCS if neither of their parents had obtained a 4-year college degree. Results suggested some support for SCCT proposed social-cognitive relationships among this sample of Latinx and White FGCS pursuing an engineering degree. In addition, results indicated that FGCS who participated in college STEM programs needed lower level of engineering goals to persist in engineering compared to those who did not participate in college STEM programs. Practical and research implications, limitations, and future directions are discussed.Includes bibliographical references

Evaluation of 4.75 mm Superpave mix criteria for West Virginia

The purpose of this research was to evaluate design parameters for 4.75 mm nominal maximum aggregate size mixes, NMAS, in West Virginia. This research was divided in two phases. During Phase I, evaluation of Superpave criteria for 4.75 mm LAMAS mixes, a variety of 4.75 mm NMAS limestone mixes were developed following Superpave methodology for low traffic volume. In Phase II, natural sand evaluation for 4.75 mm mixes; three approved Marshall designs were obtained from the WVDOT. Two of the mixes contained natural sand and the other was a 100 percent limestone mix. The Marshall mix designs were verified and then redesigned using Superpave methodology for low volume traffic. Comparison between Marshall and Superpave mixes was performed. Additionally the Asphalt Pavement Analyzer, APA, was used to evaluate rutting performance of the Superpave mixes during both phases.;Based on the results of these evaluations, recommendations for Superpave mix design parameters for 4.75 mm NMAS mixes were developed. These recommendations allow the WVDOH to use Superpave in lieu of the current Marshall Wearing III mix. (Abstract shortened by UMI.)

CANSAT Competition 2020: Best technical development by OrbiSat team

OrbiSat is a high school educational project that was part of the CANSAT SPAIN 2020 student competition organized by ESERO. This project has ranked first in the Catalonia Championship and second at the National Championship, winning the prize for the best technical development. OrbiSat has successfully fulfilled the objective of creating a mini satellite with the size of a soda can that was later launched by a rocket of the COSMIC Research UPC Students Association to analyze physical aspects of the air such as pressure, temperature, humidity, or the amount of UV solar radiation of a territory. Thanks to the CanSat presented by this team, during the launch we were able to know the presence of up to 15 chemical elements in the air. Elements ranging from hydrogen and oxygen can indicate water in the atmosphere or other greenhouse gases such as CO2 or methane. The launched rocket reached an approximate height of 532.7 ± 1.5 meters, with the sensors we were able to determine the apogee of the rocket and the subsequent release of the minisatellite and deployment of the parachute. We were also able to interrelate the altitude data with parameters such as humidity, UV radiation, presence of hydrogen, among others. The CanSat presented by the OrbiSat team had a unique design never seen before in other CanSat competitions, solving problems such as high weight and overheating. This design made by AutoCAD was an open concept where the air can refrigerate the CPU and also the 3D printed concept saved 125 grams over a third of the maximum allowed. In addition, all the data collected was broadcast in real-time and received by a ground station every 0.25 seconds. Before the launch, a simulation was completed estimating a 61 seconds flight, finally, the real flight was 59 seconds. The vast majority of the project was done during the COVID-19 pandemic, the consequence was new methodologies to carry on the project with a minimum time for the workshop and test phase that were supplied with simulations having a better performance than expecte

Osteology and chondrocranial morphology of Gastrophryne carolinensis (Anura: Microhylidae), with a review of the osteological diversity of New World microhylids

Microhylidae is a large, cosmopolitan anuran family. Recent molecular analyses have demonstrated the monophyly of the family—a conclusion that is supported by the larval morphology, coupled with the unique mode of tongue protrusion in adults, and a suite of osteological and myological characters seemingly associated with this innovation in feeding. Despite this functional constraint, osteological diversity probably exceeds that of any other anuran family, and this diversity is especially evident in the New Worldmicrohylids that comprise two clades, Gastrophryninae and Otophryninae. To facilitate comparisons among these clades, we describe the larval chondrocranium, skeletal development, and adult osteology of Gastrophryne carolinensis. We provide a phylogeneticcontext for these comparisons through a novel phylogenetic analysis of 45 microhylid genera based on data for one mitochondrial and three nuclear loci from previously published studies. Nearly all relationships within the monophyletic Gastrophryninae are resolvedwith robust support. Based on these results, we found that the larval chondrocrania of gastrophrynines share morphological features that distinguish them from Otophryne and other anurans. Among the adults, all gastrophrynines show evidence of an anterior shift ofthe jaws that is correlated with specializations in the otic region, and with the alignment of the planum antorbitale, the cartilage wall separating the nasal capsule from the orbits. The larval infrarostral and the adult mandibles lack a typical anuran mandibular symphysis, and the mentomeckelian bone of the adult is modified with a special process. The most variable part of the skull is the palate in which a neopalatine usually is absent and the vomer may be single or divided. The posteromedial processes of the hyoids of gastrophynines tend to be elaborated, and some taxa bear a peculiar transverse slit in the posterior part of the hyoid corpus. The anterior zonal elements of the pectoral girdle are reduced or absent, and the posterior parts enlarged and shifted posteriorly. Most taxa have eight presacral vertebrae; depending on the taxon the last presacral is amphicoelous or procoelous

Magnetic Gel Composites for Hyperthermia Cancer Therapy

Hyperthermia therapy is a medical treatment based on the exposition of body tissue to slightly higher temperatures than physiological (i.e., between 41 and 46 °C) to damage and kill cancer cells or to make them more susceptible to the effects of radiation and anti-cancer drugs. Among several methods suitable for heating tumor areas, magnetic hyperthermia involves the introduction of magnetic micro/nanoparticles into the tumor tissue, followed by the application of an external magnetic field at fixed frequency and amplitude. A very interesting approach for magnetic hyperthermia is the use of biocompatible thermo-responsive magnetic gels made by the incorporation of the magnetic particles into cross-linked polymer gels. Mainly because of the hysteresis loss from the magnetic particles subjected to a magnetic field, the temperature of the system goes up and, once the temperature crosses the lower critical solution temperature, thermo-responsive gels undergo large volume changes and may deliver anti-cancer drug molecules that have been previously entrapped in their networks. This tutorial review describes the main properties and formulations of magnetic gel composites conceived for magnetic hyperthermia therapy