University of Turabo

Telomerase overexpressionhas been associated directly with cancer,and the enzyme itself is recognized within the scientific communityas a cancer biomarker. BIDEA’s biosensing strip (BBS) is aninnovative technology capable of detecting the presence of telomeraseactivity (TA) using electrochemical impedance spectroscopy (EIS).This BBS is an interdigital gold (GID) electrode array similar insize and handling to a portable glucose sensor. For the detectionof the biomarker, BBS was modified by the immobilization of a telomere-likesingle strand DNA (ssDNA) on its surface. The sensor was exposed totelomerase-positive extract from commercially available cancer cells,and the EIS spectra were measured. Telomerase recognizes the sequenceof this immobilized ssDNA probe on the BBS, and the reverse transcriptionprocess that occurs in cancer cells is replicated, resulting in thessDNA probe elongation. This surface process caused by the presenceof TA generates changes in the capacitive process on the electrodearray microchip surface, which is followed by EIS as the sensing tooland correlated with the presence of cancer cells. The telomerases’total cell extraction protocol results demonstrate significant changesin the charge-transfer resistance (Rct) change rate after exposure to telomerase-positive extract witha detection limit of 2.94 × 104 cells/mL. Finally,a preliminary study with a small set of “blind” uterinebiopsy samples suggests the feasibility of using the changes in the Rct magnitude change rate (Δ(ΔRct/Rcti)/Δt) to distinguish positive from negative endometrial adenocarcinomasamples by the presence or absence of TA.

Abstract Typical design (sizing) projects in a Machine Design course tend to rely on abstractions of the machine; that is, situations in which the student must imagine the system, perhaps with the aid of a 2D schematic, and conduct the sizing calculations in a completely theoretical and abstract fashion. This skill is certainly a requirement of an experienced machine designer; however, novices may be outmatched when exposed to this level of expertise at an early stage in their development. This article suggests that the sizing projects should be based on existing machinery that is available in the university, and that is accessible for inspection and exploration by students. The sizing results are then compared to the existing machine to determine the reasonableness of the calculations. This approach “conditionalizes” knowledge and provides students with an intermediate design experience before undertaking a major machine design experience in their capstone course. Furthermore, based on the “backwards design” planning framework for designing courses, the paper suggests that the project should be approached gradually – in phases – from the first day of class, and extending throughout the semester, to provide quality feedback to students throughout the entire process, thus increasing the potential of achieving expertise. The phases were also synchronized with the material presented in class, and with the exams, to further strengthen the knowledge acquired by the students. The project specifically addressed the sizing of components of an existing SAE Baja race car gearbox (size the shafts, keys, gears, and bearings). Phases 1 and 2 of the project asked students to calculate/estimate the external loads acting on the input and output shafts of the gearbox. In these first two phases students were able to start experiencing a typical real-world situation in which, unlike textbook problems, the loads acting on the system were unknown and had to be determined. It required searching the internet, consulting textbooks, inspecting the Baja, and making assumptions. In the last phases, the students compared the results of their sizing calculations to the existing components and applied critical thinking skills (discern the true from the false and be able to explain it) to explain differences in the sizes of the components. This study is based on the literature on expertise, and the learning processes that support its development. A survey of skills, given as a pre- and post-survey to students, validates the strength of using this scheme. The survey results were further validated by direct assessment of the written reports.

Abstract A consortium of 13 Universities has been collectively implementing experiment centric pedagogy (ECP) in their ECE circuits and electronics courses. The project successfully demonstrated that ECP combined with hands-on educational technology stimulates student interest in the STEM area, promotes content acquisition, problem solving, and retention. Throughout the history of the project, it was recognized that the successful collaboration and outcomes the partnering institutions are achieving are significant. As a result, the consortium is implementing a series of follow on activities to gain a deeper understanding of how to grow and develop this work. As the initial period of funding came to an end, a workshop was held to examine the nature of the collaboration between ECP institutions; why has it been successful; can it be improved, expanded, adopted by others (especially historically minority-serving institutions) and sustained. To date, this process has yielded the adoption of a charter for a 501(c)(3) non-profit organization to carry on and facilitate the work of the group and a successfully funded REU-RET Megasite: Research Experiences for Undergraduates and Teachers in Smart and Connected Cities. The collaboration between the now 16 institutions within the ECP community will have a positive long-term impact on the development of new cooperative efforts in technical research, engineering education research and curriculum development for the institutions and is expected to have a significant impact on the retention and graduation of under-represented engineering students.

Abstract NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract The Use of Spreadsheets in Teaching Boundary-Value Problems in Electromagnetics Abstract Electromagnetics is arguably one of the most challenging courses in any electrical engineering curriculum. A solid foundation in vector calculus and a good intuition based on physical grounds are the normal requirements for a student to successfully complete this course. This paper presents a simple, yet powerful approach to introducing boundary-value problems arising in electrostatics. The principles of electrostatics find numerous applications such as electrostatic machines, lightning rods, gas purification, food purification, laser printers, and crop spraying, to name a few. This paper focuses on the use of spreadsheets for solving electrostatic boundary-value problems. Sample problems that introduce the finite difference and the finite element methods are presented. The geometries included in the problems are sufficiently nontrivial for hand calculation or analytical solution, but reasonably manageable using spreadsheets. Although specialized software is available for this purpose, oftentimes such sophistication tends to obscure the mathematical underpinnings of the solution methods. Spreadsheets offer a transparent numerical methods for solving boundary-value problems. 1. Introduction Many phenomena arising in science and engineering are modeled by partial differential equations (PDEs). In such cases the quantity of interest (e.g., temperature, potential, or displacement) is a function that depends on more than one variable (typically, space variables x, y, z and the temporal variable t). among the most common PDEs that undergraduate engineering students will encounter. The usual practice is to introduce the student to the analytical solution of these equations via the method of separation of variables. Under the assumption of linearity, the method naturally leads to the formulation of solutions as Fourier series expansions. Treatment of PDEs and boundary-value problems (BVPs) may be found in many standard books.1 4 Reference 1 provides a very accessible presentation of the topic, while references 2 through 4 provide a more concise presentation geared toward compendium courses in engineering mathematics. This paper will not expound the theories that provide the mathematical underpinnings of PDEs; instead, the paper emphasizes on numerical solutions of PDEs and suggests implementations through spreadsheets. This paper focuses on some numerical methods for solving PDEs; in particular, the finite difference and the finite element methods are presented in the context of problems arising in electrostatics. Much of the development of these methods will follow those found in electromagnetics books.5 The examples presented in this paper include geometries that are

En el valle de Apatzingn, a partir de la llegada de Diaphorina citri Kuwayama en 2006, se incrementaron las aplicaciones de productos qumicos en ctricos, debido a que es el vector del Huanglongbing (HLB). Para el control de este insecto se han hecho aplicaciones excesivas de insecticidas, lo que ha ocasionado el desarrollo de resistencia de D. citri a varios productos, adems de ocasionar la resurgencia de plagas secundarias como trips, caros, minador de la hoja, mosca prieta y mosca blanca. El objetivo del trabajo fue identificar los picos poblacionales de D. citri en el valle de Apatzingn y sus enemigos naturales, determinar la efectividad de diferentes insecticidas en el control de D. citri y evaluar la presencia y dao por de trips. Se realizaron diferentes estudios a partir del ao 2000 hasta 2019 para conocer la dinmica poblacional de D. citri, destacando su incremento en septiembre, diciembre, abril y julio. En el caso de los trips, sus poblaciones se incrementan de noviembre a mayo y decrecen de junio a octubre. Destaca la presencia de enemigos naturales como C. rufilabris y C. cincta y Zelus renardi, Stethorus sp.,

We present a study of vibrational quenching and chemical processes of molecular ions immersed in an ultracold atomic gas by means of the quasi-classical trajectory (QCT) method. In particular, BaRb$^+(v)$ + Rb collisions are studied at cold temperatures revealing a highly efficient energy transfer between the translational degrees of freedom and internal degrees of the molecular ion. Thus leading to a large vibrational quenching cross section which follows the Langevin capture model prediction. These results play a key role on the understanding of relaxation phenomena of cold molecular ions in ultracold gases as well as in the fate of the molecules emerging trough ion-neutral-neutral three-body recombination in an cold and dense environment.

PurposeThe purpose of this paper is to validate or refute the previous empirical findings of a TBL dominant logic for business sustainability and to expand the TBL dominant logic for business sustainability with additional dimensions and items. The study aims to provide bottom-up-based multi-dimensional framework in relation to the sustainable development goals (SDG) of the UN 2030 agenda for sustainable development.Design/methodology/approachKey corporate informants in top Spanish companies were requested to participate in the study. A total of 89 usable questionnaires were returned, generating an initial response rate of 42.4%.FindingsA framework for a TBL-dominant logic in the context of business sustainability has been empirically tested successfully across contexts and through time, thus providing substantiation for universal applicability.Research limitations/implicationsThis study provides a relevant and important substantiation for validity and reliability across contexts and through time. It is important in research to establish a theoretical framework at the corporate level for business sustainability in connection with SDGs. This study is not without its limitations, but offers opportunities for further research.Practical implicationsThe framework provides practitioners with a foundation to assess their efforts at business sustainability, taking into account a broad selection of aspects across environmental, social and economic elements that contribute to SDGs.Originality/valueThis study makes two relevant and valuable contributions to developing a framework of TBL dominant logic for business sustainability, namely, validation and expansion. It offers also multiple opportunities for both research and practice to assess business sustainability efforts across environmental, social and economic aspects in relation to SDGs.

Hydrogenated amorphous silicon (a-Si:H) has recently proved to be a suitable base material for the synthesis of silicon nanowires (SiNWs) by metal-assisted chemical etching (MACE). The etching procedure on this material shows an extraordinary sensitivity to slight compositional changes and, although dopant influence on the process has been previously addressed, little is known on the role of hydrogen. In this article, we have studied the behavior of MACE on a-Si:H films with different hydrogen contents and bond configurations. As-grown films were studied by Raman spectroscopy, Fourier transform infrared spectroscopy, and ion beam analysis to obtain a complete description of the material composition. Additionally, these results were further correlated with the morphology and characteristics of the obtained SiNWs, showing that the material stability under MACE is reduced as the bond configuration is shifted from monohydrides to polyhydrides. The effect of bond configuration has an extraordinary importance r...

The linguistic maneuvers of the work collected in Silent Dancing: A Partial Remembrance of a Puerto Rican Childhood demonstrate that Judith Ortiz Cofer tells her stories of the past as a means to a...