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When teaching STEM courses, it is important to introduce state-of-the-art techniques. Students need to learn how to conduct experiments, analyse data and choose the most effective approaches to address meaningful situations. Here we present the assessment of the implementation of a structured inquiry-based activity aimed at teaching students about protein mass and size. This activity emerges as an intervention in our educational module, designed to create a cognitive conflict that effectively drives a conceptual change. To evaluate the efficacy of this module, we collected data on students' perceived and actual knowledge through pre- and post-class surveys (n = 36 and 34, respectively, mean age 26 ± 2). Additionally, we evaluated lab reports using a detailed rubric. Results indicate that the practical innovation we propose is a challenging activity that promotes the accomplishment of our learning objectives. The activity led to improvements both in confidence and in actual mastery of theoretical concepts and techniques. After completing the activity, students were able to choose the most appropriate technique to solve specific problems. Furthermore, we found that the use of a structured questionnaire in lab reports helped students to accurately analyse and process experimental data. It also allows them to demonstrate understanding of technical limitations, while integrating the knowledge and skills acquired during the module. Overall, this activity provides notions that are conceivable and profitable, thus leading to successful conceptual changes.

Introductory courses are often designed to cover a range of topics with the intent to offer students exposure to the given discipline as preparation to further their study in the same or related disciplines. Unfortunately, students in these courses are often presented with an overwhelming amount of information that may not support their formation of a usable coherent network of knowledge. In this study we conducted a mixed-method sequential exploratory study with students co-enrolled in General Chemistry II and Introductory Biology I to better understand what students perceived to be the "take-home" messages of these courses (i.e., core ideas) and the connections between these courses. We found that students identified a range of ideas from both courses; further analysis of students' explanations and reasoning revealed that, when students talked about their chemistry ideas, they were more likely to talk about them as having predictive and explanatory power in comparison with reasons provided for their biology big ideas. Furthermore, students identified a number of overlapping ideas between their chemistry and biology courses, such as interactions, reactions, and structures, which have the potential to be used as a starting place to support students building a more coherent network of knowledge.

Background: Classification of athletes in cerebral palsy (CP) football is a key action that aims to promote the participation of all players by minimizing the impact of their physical disabilities on the outcome of the competition by establishing sports classes. As such, a new research line has been included in the classification process at an international level; that is, the analysis of locomotor demands during competition helps classifiers to understand the para-footballers’ profile. Therefore, the main aim of this systematic review was to summarize the physical and physiological responses of players with CP in different sport classes during competition. Methods: A bibliographic search was conducted using PubMed, SCOPUS, and Web Of Science databases following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines using the PICOS strategy. Results: Six studies meeting inclusion criteria analyzing physical (i.e., total distances, distances at different speeds, high-intensity and short-term actions, change of directions, etc.) and physiological (heart rate (HR), time spent at different zones of maximum HR, etc.) responses. Findings revealed that para-footballers with CP and minimal impairment impact covered greater total and distance above 23.04 km·h−1 and achieved higher maximum speeds during match-play. Notably, no significant differences in physiological responses were observed based on classification. Conclusions: The research suggests that para-footballers with CP and lower physical impairment may exhibit enhanced performance in terms of distance covered and speed during gameplay, highlighting their potential competence in the sport. In addition, the limited number of studies examining the physiological response of para-footballers prevents conclusive results and differentiating between classification groups.

This study aimed to compare the acute effect of four back squat velocity-based training (VBT) protocols in terms of intensity (60% vs. 80% of the one repetition maximum [1RM]) and volume (10% vs. 30% threshold for velocity loss in the set) on the maximal aerobic speed (MAS) estimated from a running track test (RTT) in recreationally trained young adult men and women. Twenty participants (eleven men and nine women) undertook five randomized protocols in separate occasions: (i) RTT alone (control condition); (ii) VBT with 60% 1RM and a 10% velocity loss followed by RTT (VBT60–10 + RTT); (iii) VBT with 60% 1RM and a 30% velocity loss followed by RTT (VBT60–30 + RTT); (iv) VBT with 80% 1RM and 10% velocity loss followed by RTT (VBT80–10 + RTT); (v) VBT with 80% 1RM and 30% velocity loss followed by RTT (VBT80–30 + RTT). All VBT protocols involved three sets with three minutes of rest. The MAS was higher for RTT (control) than VBT60–30 + RTT (p < 0.001; Δ = 3.8%), VBT60–10 + RTT (p = 0.006; Δ = 2.8%), VBT80–10 + RTT (p = 0.008; Δ = 2.7%), and VBT80–30 + RTT (p = 0.019; Δ = 1.9%). No protocol × sex interaction was noted (p = 0.422). Therefore, regardless of sex, MAS is acutely impaired after VBT, especially if the training sets are performed with a low relative load and a high velocity loss threshold.

A computational laboratory experiment is carried out to investigate the size-, geometry-, and chemistry-dependent properties of small molecules known as polycyclic aromatic hydrocarbons (PAHs) at the Facultad de Ingeniería (Universidad Nacional de La Plata, UNLP), Buenos Aires, Argentina. This computational research was adapted for upper-division undergraduate and initial graduate education levels. Due to the adverse circumstances of the pandemic, students were challenged to perform theoretical calculations on a regular computer at home. They were able to model PAH molecules similar to graphene quantum dots (GQDs) and learn how to use various open and freely available softwares, including visual molecular dynamics (VMD), Avogadro, nanoHUB.org, and ORCA. Through these computational tools, students designed PAHs of various sizes, geometries, and functional groups in order to study some of their optoelectronic properties. They simulated UV-vis absorbance spectra based on changes in size, geometry, and chemistry at the edges of the GQDs. Students then calculated the energy of the HOMO-LUMO gap and compared using three different methods included in ORCA corresponding to Hartree-Fock (H-F) approximation, density functional theory (DFT), and time-dependent DFT (TD-DFT). Finally, based on the results obtained, students propose the construction of more efficient solar devices by tuning the size and geometry of GQDs.

Minorities' languages face transformation processes and struggle against many social and linguistic limitations. Education systems in these languages are not optimal to promote the teaching of ancestral knowledge and scientific research. This is the case of Kichwa, an Ecuadorian native language that more than half-million people speak with different variations among the country. Kichwa lacks science tools to respond to educational needs, unleashing the gradual loss of intercultural diversity. The adaptation of the periodic table to Kichwa was developed in this work, taking into account its different language variations and the Kichwa speaker's opinion to ensure the acceptance of this scientific tool. This research aims to break barriers in the development and conservation of indigenous people's intellect by promoting Kichwa deep-rooted writing and enhancing an excellent bilingual intercultural education system in Ecuador.

In December 2019, the institutional affirmative action "Onde elas estão?" ("Where are they?") was launched for the mitigation of gender inequality in the STEM disciplines in Brazil, coincidentally in the same period which the first reports of the COVID-19 pandemic appeared in the city of Wuhan, China. Unfortunately, when evaluating the initiative through different approaches belonging to the Diversity, Equity, Inclusion, and Respect (DEIR) theories, the presence of implicit biases and the invisibility of underrepresented minorities was observed. Approximately 77.5% of the female scientists participating in the initiative were white and belonging to the wealthiest regions (75%) and with the greatest contribution to Brazil's Gross Domestic Product (GDP). On the other hand, Black, Indigenous, and Asian female chemists were not identified, nor were female chemists belonging to the North Region (Brazilian Amazon Region). The DEIR practice "Onde elas estão?" has an important role in the dissemination of highly qualified Brazilian female chemists and provides an important source of engagement and sense of community for future generations of female students to avoid abandoning STEM subjects. However, adjustments are needed that take into account greater Diversity, Inclusion, Equity, and Respect.

This review aims to synthesize and discuss the potential effects of a stack height modification on the function of the different footwear features and their effects on running performance. Peer-reviewed studies were identified from electronic databases using a structured keyword search and a screening process. Complementary sources were used to illustrate and discuss the current racing footwear constructions. With regard to the shoe mass, it is suggested that a stack height difference of 20 mm could induce a meaningful effect on performance. With respect to the midsole properties, it seems that reducing the stack height does not alter the energy returned, given that the lower midsole deformation is counteracted with an increased stiffness. However, it should be noted that this might affect the timing of the midsole deformation and restitution, which should be matched with the mid and propulsive stance phases. Lastly, the curved geometry of the forefoot sole needed to create the teeter-totter effect could be affected by the stack height reduction. However, current racing footwear designs have counteracted this modification by proximately placing the rocker axis and increasing the toe spring.

Thirty-six days after the beginning of the 2020 school year in Brazil, the Rio de Janeiro state education system began an unprecedented disruptive period due to the COVID-19 crisis, which abruptly affected general educational activities, particularly chemistry teaching. An adaptation to a new paradigm of remote teaching and massive use of online educational technology alternatives was tentatively performed, generating lessons for improving implemented actions. Educational institutions prepared independent teaching strategies to provide remote chemistry classes for a total of nearly 397,700 students who were able to begin or continue chemistry classes. This "snapshot" of a daily-life reality faced by professionals engaged in chemistry education in Rio de Janeiro's schools identified the following factors that negatively affected the implemented actions: the applied television broadcaster essentially covered only the heavily urbanized region, leaving out rural and impoverished areas; a significant absence of adequate technological equipment (e.g., smartphones, tablets, notebooks) for students; pedagogical limitations of instructors, without sufficient training to use online technologies; and inherent limitations of video classes, which do not adequately substitute for practical learning in chemistry laboratories. Strategy improvements are imperative, considering that students face the challenge of increasingly being protagonists for the organization and management of the teaching--learning process.

Three days into the academic year, the COVID-19 pandemic abruptly led to emergency remote teaching, ERT, of Chemical Experimentation--a revised alternative to the majors' General Chemistry Laboratory at the University of Costa Rica. The course was reoriented to support students' development of nontechnical experimentation skills and scientific practices relevant to the conventional course. Assignments ranged from problem-based projects to prescriptive online simulations, included team and individual work, lasted one or several weeks, and were hands-on or relied on computer-based animations, simulations, and demonstrations. Assignments were completed asynchronously and supported by synchronous weekly discussion sessions, extended office hours, and online forums. Online modules on topics pertinent to the course were available for perusal at students' convenience. Instruction of technical skills was deferred until public health conditions allow. End-of-course survey data suggest the ERT course effectively supported development of nontechnical experimental skills and scientific practices, e.g., asking scientific questions, planning and executing investigations, collecting, analyzing, and constructing explanations, creating arguments from evidence, and obtaining, evaluating, and communicating scientific information. Ongoing phenomenological work will advance the understanding of the nature and extent of learning during ERT and how it occurred. Although in-laboratory experiences are not completely substitutable, course designs may incorporate meaningful activities away from the lab to fulfill some of the objectives of experimental instruction. Current concerns over academic laboratory costs make optimization of instructional resources compelling. This communication describes the context, the course model, and basics of the ERT design.

The increasing integration of software and automation in modern chemical laboratories prompts special emphasis on two important skills in the chemistry classroom. First, students need to learn the technical skills involved in modern scientific computing and automation. Second, applying these techniques in practice requires effective collaboration in teams. This work aims at developing a teaching module to help students gain both skills. In particular, we describe a modular and collaborative approach for introducing undergraduate students to scientific computing in the context of automated and autonomous chemical laboratories. Using online collaboration tools, students work in parallel teams to develop central components of an automated computer vision system that monitors color changes in ongoing chemical reactions. These components include three different aspects: image capture, communication, and data visualization. The image capture team collects and stores the images of the chemical reaction, the communication team processes the images, and the visualization team develops the tools for analyzing the processed image data. Using this educational framework, students built an open-source Python tool called AutoVis that enables the automated tracking of color and intensity changes in a liquid. The software is tested by simulating chemical reactions with dilute solutions of food coloring in water. It is shown that the system reliably tracks color and intensity, providing feedback to the experimentalist and enabling further computational analysis. Over the course of the project, students gain proficiency in scientific computing using Python and collaborate on software development using GitHub. In this way, they learn the role of software in chemical laboratories of the future.

Type 2 diabetes (T2D) is responsible for high incidence of cardiovascular (CV) complications leading to heart failure. Coronary artery region-specific metabolic and structural assessment could provide deeper insight into the extent of the disease and help prevent adverse cardiac events. Therefore, in this study, we aimed at investigating such myocardial dynamics for the first time in insulin-sensitive (mIS) and insulin-resistant (mIR) T2D patients. We targeted global and region-specific variations using insulin sensitivity (IS) and coronary artery calcifications (CACs) as CV risk factor in T2D patients. IS was computed using myocardial segmentation approaches at both baseline and after an hyperglycemic–insulinemic clamp (HEC) on [18F]FDG-PET images using the standardized uptake value (SUV) (ΔSUV = SUVHEC − SUVBASELINE) and calcifications using CT Calcium Scoring. Results suggest that some communicating pathways between response to insulin and calcification are present in the myocardium, whilst differences between coronary arteries were only observed in the mIS cohort. Risk indicators were mostly observed for mIR and highly calcified subjects, which supports previously stated findings that exhibit a distinguished exposure depending on the impairment of response to insulin, while projecting added potential complications due to arterial obstruction. Moreover, a pattern relating calcification and T2D phenotypes was observed suggesting the avoidance of insulin treatment in mIS but its endorsement in mIR subjects. The right coronary artery displayed more ΔSUV, whilst plaque was more present in the circumflex. However, differences between phenotypes, and therefore CV risk, were associated to left descending artery (LAD) translating into higher CACs regarding IR, which could explain why insulin treatment was effective for LAD at the expense of higher likelihood of plaque accumulation. Personalized approaches to assess T2D may lead to more efficient treatments and risk-prevention strategies.

In hospitalized COVID-19 patients, disease progression leading to acute kidney injury (AKI) may be driven by immune dysregulation. We explored the role of urinary cytokines and their relationship with kidney stress biomarkers in COVID-19 patients before and after the development of AKI. Of 51 patients, 54.9% developed AKI. The principal component analysis indicated that in subclinical AKI, epidermal growth factor (EGF) and interferon (IFN)-α were associated with a lower risk of AKI, while interleukin-12 (IL-12) and macrophage inflammatory protein (MIP)-1β were associated with a higher risk of AKI. After the manifestation of AKI, EGF and IFN-α remained associated with a lower risk of AKI, while IL-1 receptor (IL-1R), granulocyte-colony stimulating factor (G-CSF), interferon-gamma-inducible protein 10 (IP-10) and IL-5 were associated with a higher risk of AKI. EGF had an inverse correlation with kidney stress biomarkers. Subclinical AKI was characterized by a significant up-regulation of kidney stress biomarkers and proinflammatory cytokines. The lack of EGF regenerative effects and IFN-α antiviral activity seemed crucial for renal disease progression. AKI involved a proinflammatory urinary cytokine storm.

Lung cancer is the first leading cause of cancer-related deaths in the world. Aberrant glycosylation in lung tumors leads to the expression of tumor-associated carbohydrate structures, such as the Tn antigen, consisting of N-acetyl-galactosamine (GalNAc) linked to a serine or threonine residue in proteins (α-GalNAc-O-Ser/Thr). The Tn antigen can be recognized by the Macrophage Galactose/GalNAc lectin (MGL), which mediates various immune regulatory and tolerogenic functions, mainly by reprogramming the maturation of function of dendritic cells (DCs). In this work, we generated two different Tn-expressing variants from the Lewis-type lung murine cancer cell line LL/2, which showed different alterations in the O-glycosylation pathways that influenced the interaction with mouse MGL2 and the immunomodulatory properties of DCs. Thus, the identification of the biological programs triggered by Tn+ cancer cells might contribute to an improved understanding of the molecular mechanisms elicited by MGL-dependent immune regulatory circuits.

Background: We report that myocardial insulin resistance (mIR) occurs in around 60% of patients with type 2 diabetes (T2D) and was associated with higher cardiovascular risk in comparison with patients with insulin-sensitive myocardium (mIS). These two phenotypes (mIR vs. mIS) can only be assessed using time-consuming and expensive methods. The aim of the present study is to search a simple and reliable surrogate to identify both phenotypes. Methods: Forty-seven patients with T2D underwent myocardial [18F]FDG PET/CT at baseline and after a hyperinsulinemic–euglycemic clamp (HEC) to determine mIR were prospectively recruited. Biochemical assessments were performed before and after the HEC. Baseline hepatic steatosis index and index of hepatic fibrosis (FIB-4) were calculated. Furthermore, liver stiffness measurement was performed using transient elastography. Results: The best model to predict the presence of mIR was the combination of transaminases, protein levels, FIB-4 score and HOMA (AUC = 0.95; sensibility: 0.81; specificity: 0.95). We observed significantly higher levels of fibrosis in patients with mIR than in those with mIS (p = 0.034). In addition, we found that patients with mIR presented a reduced glucose uptake by the liver in comparison with patients with mIS. Conclusions: The combination of HOMA, protein, transaminases and FIB-4 is a simple and reliable tool for identifying mIR in patients with T2D. This information will be useful to improve the stratification of cardiovascular risk in T2D.

Getting students to use grading feedback as a tool for learning is a continual challenge for educators. This work proposes a method for evaluating student performance that provides feedback to students based on standards of learning dictated by clearly delineated course learning outcomes. This method combines elements of standards-based grading into a framework that uses Marzano's Taxonomy of Learning to guide the writing of clearly defined and scaffolded learning outcomes. By means of this methodology, students are equipped with increased levels of information obtained from assessments, both formative and summative. Students and faculty alike can more accurately diagnose strengths and weaknesses in learning down to the level of the concept(s). Early observations from a first-semester general chemistry course suggest that setting transparent standards for grading can serve as a valuable learning tool for students to allow them to focus on content proficiency rather than grades alone.

Distance learning has been adopted as a very extended model during COVID-19-related confinement. It is also a methodology that can be applied in environments where people do not have easy access to schools. In this study, we automatically classify students as a function of their performance and we describe the best self-learning methodologies in distance learning, which will be useful both in confinement or for people with difficult access to schools. Due to the different learning scenarios provided by the different confinement conditions in the COVID-19 pandemic, we have performed the classification considering data before, during, and after COVID-19 confinement. Using a field experiment of 396 students, we have described the temporal evolution of students during all courses from 2016/2017 to 2020/2021. We have found that data obtained in the last month before the final exam of the subject include the most relevant information for a correct detection of students at risk of failure. On the other hand, students who obtain high scores are much easier to identify. Finally, we have concluded that the distance learning applied in COVID-19 confinement changed not only teaching strategies but also students’ strategies when learning autonomously.

Carbon nanotubes (CNTs) have attracted the attention of academy and industry due to their potential applications, being currently produced and commercialized at a mass scale, but their possible impact on different biological systems remains unclear. In the present work, an assessment to understand the toxicity of commercial pristine multi-walled carbon nanotubes (MWCNTs) on the unicellular fungal model Saccharomyces cerevisiae is presented. Firstly, the nanomaterial was physico-chemically characterized, to obtain insights concerning its morphological features and elemental composition. Afterwards, a toxicology assessment was carried out, where it could be observed that cell proliferation was negatively affected only in the presence of 800 mg L−1 for 24 h, while oxidative stress was induced at a lower concentration (160 mg L−1) after a short exposure period (2 h). Finally, to identify possible toxicity pathways induced by the selected MWCNTs, the transcriptome of S. cerevisiae exposed to 160 and 800 mg L−1, for two hours, was studied. In contrast to a previous study, reporting massive transcriptional changes when yeast cells were exposed to graphene nanoplatelets in the same exposure conditions, only a small number of genes (130) showed significant transcriptional changes in the presence of MWCNTs, in the higher concentration tested (800 mg L−1), and most of them were found to be downregulated, indicating a limited biological response of the yeast cells exposed to the selected pristine commercial CNTs.

This paper is devoted to a type of combined impulsive discrete Beverton–Holt equations in ecology when eventual discontinuities at sampling time instants are considered. Such discontinuities could be interpreted as impulses in the corresponding continuous-time logistic equations. The set of equations involve competition-type coupled dynamics among a finite set of species. It is assumed that, in general, the intrinsic growth rates and the carrying capacities are eventually distinct for the various species. The impulsive parts of the equations are parameterized by harvesting quotas and independent consumptions which are also eventually distinct for the various species and which control the populations’ evolution. The performed study includes the existence of extinction and non-extinction equilibrium points, the conditions of non-negativity and boundedness of the solutions for given finite non-negative initial conditions and the conditions of asymptotic stability without or with extinction of the solutions.

The impact of the SARS-CoV-2 (COVID-19) on the world has been partially controlled through different measures of social isolation and prophylaxis. Two new SEIR (Susceptible-Exposed-Infected-Recovered) models are proposed in order to describe this spread through different countries of Europe. In both models the infectivity of the asymptomatic period during the exposed stage of the disease will be taken into account. The different transmission rates of the SEIR models are calculated by considering the different locations and, more importantly, the lockdown measures implemented in each region. A new classification of these intervention measures will be set and their influence on the values of the transmission rates will be estimated through regression analysis.

Peter Day was one of the most asiduous participants of the NoSIC (Not Strictly Inorganic Chemistry) meetings, where he showed his interest in, and knowledge of, historical, sociological and other non-scientific aspects of the research activities in the institutions led by him as well as in those he visited worldwide, both as a lecturer and as an active participant. This article tries to stress that side of his personality, reflected also in his three autobiographical books, and in his motto “the past is another country”, a quotation from L.P. Hartley.

Macrophages were first described as phagocytic immune cells responsible for maintaining tissue homeostasis by the removal of pathogens that disturb normal function. Historically, macrophages have been viewed as terminally differentiated monocyte-derived cells that originated through hematopoiesis and infiltrated multiple tissues in the presence of inflammation or during turnover in normal homeostasis. However, improved cell detection and fate-mapping strategies have elucidated the various lineages of tissue-resident macrophages, which can derive from embryonic origins independent of hematopoiesis and monocyte infiltration. The role of resident macrophages in organs such as the skin, liver, and the lungs have been well characterized, revealing functions well beyond a pure phagocytic and immunological role. In the heart, recent research has begun to decipher the functional roles of various tissue-resident macrophage populations through fate mapping and genetic depletion studies. Several of these studies have elucidated the novel and unexpected roles of cardiac-resident macrophages in homeostasis, including maintaining mitochondrial function, facilitating cardiac conduction, coronary development, and lymphangiogenesis, among others. Additionally, following cardiac injury, cardiac-resident macrophages adopt diverse functions such as the clearance of necrotic and apoptotic cells and debris, a reduction in the inflammatory monocyte infiltration, promotion of angiogenesis, amelioration of inflammation, and hypertrophy in the remaining myocardium, overall limiting damage extension. The present review discusses the origin, development, characterization, and function of cardiac macrophages in homeostasis, cardiac regeneration, and after cardiac injury or stress.

By means of QM(DFT)/MM metadynamics we have unraveled the hydrolytic reaction mechanism of Neisseria polysaccharea amylosucrase (NpAS), a member of GH13 family. Our results provide an atomistic picture of the active site reorganization along the catalytic double-displacement reaction, clarifying whether the glycosyl-enzyme reaction intermediate features an α-glucosyl unit in an undistorted 4C1 conformation, as inferred from structural studies, or a distorted 1S3-like conformation, as expected from mechanistic analysis of glycoside hydrolases (GHs). We show that, even though the first step of the reaction (glycosylation) results in a 4C1 conformation, the α-glucosyl unit undergoes an easy conformational change toward a distorted conformation as the active site preorganizes for the forthcoming reaction step (deglycosylation), in which an acceptor molecule, i.e., a water molecule for the hydrolytic reaction, performs a nucleophilic attack on the anomeric carbon. The two conformations (4C1 ad E3) can be viewed as two different states of the glycosyl-enzyme intermediate (GEI), but only the E3 state is preactivated for catalysis. These results are consistent with the general conformational itinerary observed for α-glucosidases.

Nanoscience and nanotechnology have reached the syllabi of many upper-division undergraduate and master level courses all over the world. There is therefore a growing need for practical exercises that illustrate the fabrication, characterization, properties, and applications of nanomaterials. Here we describe an advanced-level laboratory experiment in which students had the opportunity to fabricate surfaces modified by ordered monolayers and nanostructured materials. The surface modification was quantified by means of a quartz crystal microbalance, while the electrochemical properties of the nanoarchitectures were assessed using cyclic voltammetry experiments. Electron transfer across self-assembled monolayers mediated by gold nanoparticles was presented as a topic for discussion, and consideration of potential practical applications of the observed phenomena (catalytic and electrocatalytic processes, as well as development of optical, (opto)electronic, and photovoltaic devices with enhanced properties) was proposed as a further reading exercise.

An emphasis on higher-order thinking within the curriculum has been a subject of interest in the chemical and STEM literature due to its ability to promote meaningful, transferable learning in students. The systematic use of learning taxonomies could be a practical way to scaffold student learning in order to achieve this goal. This work proposes the use of Marzano's Taxonomy of Learning. Because it offers a functional way to distinguish lower from higher-order thinking, the taxonomy is particularly useful to instructors interested in helping students develop these skills. We outline and provide examples of how it was used in constructing Student Learning Outcomes (SLOs), class activities, and assessments for a first semester general chemistry course. Preliminary observations of the impact of this methodology on student learning are presented.

This paper investigates a susceptible-exposed-infectious-recovered (SEIR) epidemic model with demography under two vaccination effort strategies. Firstly, the model is investigated under vaccination of newborns, which is fact in a direct action on the recruitment level of the model. Secondly, it is investigated under a periodic impulsive vaccination on the susceptible in the sense that the vaccination impulses are concentrated in practice in very short time intervals around a set of impulsive time instants subject to constant inter-vaccination periods. Both strategies can be adapted, if desired, to the time-varying levels of susceptible in the sense that the control efforts be increased as those susceptible levels increase. The model is discussed in terms of suitable properties like the positivity of the solutions, the existence and allocation of equilibrium points, and stability concerns related to the values of the basic reproduction number. It is proven that the basic reproduction number lies below unity, so that the disease-free equilibrium point is asymptotically stable for larger values of the disease transmission rates under vaccination controls compared to the case of absence of vaccination. It is also proven that the endemic equilibrium point is not reachable if the disease-free one is stable and that the disease-free equilibrium point is unstable if the reproduction number exceeds unity while the endemic equilibrium point is stable. Several numerical results are investigated for both vaccination rules with the option of adapting through ime the corresponding efforts to the levels of susceptibility. Such simulation examples are performed under parameterizations related to the current SARS-COVID 19 pandemic.

This paper studies and proposes some supervisory techniques to update the vaccination and control gains through time in a modified SI (susceptible-infectious) epidemic model involving the susceptible and subpopulations. Since the presence of linear feedback controls are admitted, a compensatory recovered (or immune) extra subpopulation is added to the model under zero initial conditions to deal with the recovered subpopulations transferred from the vaccination and antiviral/antibiotic treatment on the susceptible and the infectious, respectively. Therefore, the modified model is referred to as an SI(RC) epidemic model since it integrates the susceptible, infectious and compensatory recovered subpopulations. The defined time-integral supervisory loss function can evaluate weighted losses involving, in general, both the susceptible and the infectious subpopulations. It is admitted, as a valid supervisory loss function, that which involves only either the infectious or the susceptible subpopulations. Its concrete definition involving only the infectious is related to the Shannon information entropy. The supervision problem is basically based on the implementation of a parallel control structure with different potential control gains to be judiciously selected and updated through time. A higher decision level structure of the supervisory scheme updates the appropriate active controller (i.e., that with the control gain values to be used along the next time window), as well as the switching time instants. In this way, the active controller is that which provides the best associated supervisory loss function along the next inter-switching time interval. Basically, a switching action from one active controller to another one is decided as a better value of the supervisory loss function is detected for distinct controller gain values to the current ones.

Ecto-nucleotidase triphosphate diphosphohydrolase-2 (NTPDase2) is an ecto-enzyme that is expressed on portal fibroblasts in the liver that modulates P2 receptor signaling by regulating local concentrations of extracellular ATP and ADP. NTPDase2 has protective properties in liver fibrosis and may impact bile duct epithelial turnover. Here, we study the role of NTPDase2 in acute liver injury using an experimental model of acetaminophen (APAP) intoxication in mice with global deletion of NTPDase2. Acute liver toxicity was caused by administration of acetaminophen in wild type (WT) and NTPDase2-deficient (Entpd2 null) mice. The extent of liver injury was compared by histology and serum alanine transaminase (ALT). Markers of inflammation, regeneration and fibrosis were determined by qPCR). We found that Entpd2 expression is significantly upregulated after acetaminophen-induced hepatotoxicity. Entpd2 null mice showed significantly more necrosis and higher serum ALT compared to WT. Hepatic expression of IL-6 and PDGF-B are higher in Entpd2 null mice. Our data suggest inducible and protective roles of portal fibroblast-expressed NTPDase2 in acute necrotizing liver injury. Further studies should investigate the relevance of these purinergic pathways in hepatic periportal and sinusoidal biology as such advances in understanding might provide possible therapeutic targets.

This paper provides an innovative deep learning architecture to improve collaborative filtering results in recommender systems. It exploits the potential of the reliability concept to raise predictions and recommendations quality by incorporating prediction errors (reliabilities) in the deep learning layers. The underlying idea is to recommend highly predicted items that also have been found as reliable ones. We use the deep learning architecture to extract the existing non-linear relations between predictions, reliabilities, and accurate recommendations. The proposed architecture consists of three related stages, providing three stacked abstraction levels: (a) real prediction errors, (b) predicted errors (reliabilities), and (c) predicted ratings (predictions). In turn, each abstraction level requires a learning process: (a) Matrix Factorization from ratings, (b) Multilayer Neural Network fed with real prediction errors and hidden factors, and (c) Multilayer Neural Network fed with reliabilities and hidden factors. A complete set of experiments has been run involving three representative and open datasets and a state-of-the-art baseline. The results show strong prediction improvements and also important recommendation improvements, particularly for the recall quality measure.

RateMyProfessors.com (RMP) is the most popular commercial website to evaluate instructors, and houses a wealth of student-generated information in the form of ratings and reviews. This study investigated whether general chemistry students who use RMP were different from other students, and their reasons to use and contribute to the site. A pool of 398 students were surveyed. The survey gathered demographic information, patterns and frequency of use, and information to characterise participants in terms of their learning/grade orientation. Data analysis included descriptive and inferential statistics and the application of mixture models (latent class analysis and latent profile analysis). There were no significant differences between contributors and non-contributors in terms of gender, major, year status, grade point average, course load, previous chemistry grade and learning/grade orientation. Findings for this sample do not support the common assumption that students use RMP to shop for easy instructors. Instructor helpfulness, clarity and overall rating were reported as important aspects to visit the site. Findings agree with literature reports and support the use of RMP as supplemental data to inform assessment of instruction at the general chemistry programme level. Programmes in other disciplines can adapt the methods presented to assess the suitability of RMP data-sets for similar purposes.

Two graphic holistic metrics for assessing the greenness of synthesis, the "green star" and the "green circle", have been presented previously. These metrics assess the greenness by the degree of accomplishment of each of the 12 principles of green chemistry that apply to the case under evaluation. The criteria for assessment were based on the hazards symbols used in the system established by the European Union, directive 67/548/EEC, obtained from the safety data sheets of chemicals. Meanwhile, the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) replaced that system and introduced a new classification of hazards and new symbols. The objective of this work is to present new criteria for the construction of the metrics based on the GHS system. A brief presentation of this system is included. The present upgrade also includes an improvement of the graphic presentation of the green star to facilitate the visual assessment of the degree of accomplishment of each green chemistry principle.

A simple experiment designed to study mixing of a material of complex rheology in a stirred tank is described. Non-Newtonian suspensions of blue maize flour that naturally contain anthocyanins have been chosen as a model fluid. These anthocyanins act as a native, wide spectrum pH indicator exhibiting greenish colors in alkaline environments, blue tones in neutral conditions, and pink-violet colors in acid environments. Students used a continuous injection of a basic solution in an initially acidic environment to reveal mixing patterns and flow structures and to follow their evolution over time in a typical stirred tank configuration. These experiments aim to demonstrate, in a laboratory setting, basic concepts related to mixing: (i) the existence of mixing pathologies in laminar-stirred tanks; (ii) the complex rheology of some real suspensions; (iii) the effect of tank geometry on mixing performance; and (iv) the quantitation of mixedness and mixing evolution using digital color analysis.

Self-explaining refers to the generation of inferences about causal connections between objects and events. In science, this may be summarised as making sense of how and why actual or hypothetical phenomena take place. Research findings in educational psychology show that implementing activities that elicit self-explaining improves learning in general and specifically enhances authentic learning in the sciences. Research also suggests that self-explaining influences many aspects of cognition, including acquisition of problem-solving skills and conceptual understanding. Although the evidence that links self-explaining and learning is substantial, most of the research has been conducted in experimental settings. There remains a need for research conducted in the context of real college science learning environments. Working to address that need, the larger project in which this work is embedded studied the following: (a) the effect of different self-explaining tasks on self-explaining behaviour and (b) the effect of engaging in different levels of self-explaining on learning chemistry concepts. The present study used a multi-condition, mixed-method approach to categorise student self-explaining behaviours in response to learning tasks. Students were randomly assigned to conditions that included the following: explaining correct and incorrect answers, explaining agreement with another's answer, and explaining one's own answer for others to use. Textual, individual data was gathered in the classroom ecology of a university, large-enrollment general chemistry course. Findings support an association between the self-explaining tasks and students' self-explaining behaviours. Thoughtful design of learning tasks can effectively elicit engagement in sophisticated self-explaining in natural, large-enrollment college chemistry classroom environments.

This work presents experimental and computational studies on ZnO formation after decomposition of a sol-gel precursor containing ethanolamine and Zn(II) acetate. The structural modifications suffered during decomposition of the monomeric and dimeric Zn(II) complexes formed, containing bidentate deprotonated ethanolamine and acetato ligands, have been described experimentally and explained via Car-Parrinello Molecular Dynamics. Additional metadynamics simulations provide an overview of the dimer evolution by the cleavage of the Zn−N bond, the structural changes produced and their effects on the Zn(II) environment. The results provide conclusive evidence of the relevance of ethanolamine used as a stabilizer in the formation of ZnO.

Laboratory graduate teaching assistants (GTAs) play a prominent role in undergraduate chemistry education. Although the success of a laboratory program relies significantly on the performance of GTAs, only rarely have they been considered actual partners in instruction or have their experiences in the academic lab been investigated. This paper reports on an embedded multiple case study designed to investigate how chemistry graduate students in two independent and very different learning environments constructed their GTA self-image and what aspects contributed to this process. Participants in this study included 13 GTAs from an expository-based program and 11 GTAs from an inquiry-based program. Interviews, memos, training artifacts, laboratory manuals, and course syllabi were collected to generate case reports for each program. Findings suggest that GTAs' construction of their self-image is shaped through the interaction of several factors: prior experiences, training, beliefs about the nature of knowledge and about the nature of academic laboratory work, and involvement in the laboratory setting. Findings from this study encourage laboratory coordinators to reconsider GTA participation in instruction in a new and different light and, when applicable, to look at their training and support from a new angle. Instead of focusing exclusively on what and how to teach, lab coordinators may design training and support programs that also target the factors that influence construction of GTA self-image. A more fruitful experience is attainable for students and GTAs insofar as the graduate students develop a teaching assistant self-image consistent with the specific instructional objectives.

Commercial online instructor evaluations have gained traction in influencing students' decisions on professor and course selections at universities. RateMyProfessors.com (RMP) is the most popular of such evaluation tools and houses a wealth of information from the students' viewpoint. The purpose of this study was to determine whether RMP data could be used to analyze and inform general chemistry instruction at a particular institution. The entire RMP database for the general chemistry program was sampled to produce a subset of 60 random RMP entries from six instructors. Each entry was composed of ratings in several areas and open-ended comments. The quantitative RMP data were consistent with measures from the institutional Student Evaluation of Instruction forms corresponding to the same instructors. In addition, a survey investigating RMP use patterns demonstrated that general chemistry students who contributed to RMP were not significantly different from the rest of the cohort across seven academic and demographic comparison criteria. The RMP qualitative information was analyzed using an inductive approach from which seven categories emerged as important to students' learning environment. This analytical model allows for categorizing students' statements in a systematic and meaningful manner to extract valuable supplemental information usable for program evaluation. (Contains 4 tables and 2 figures.)

While most scientists agree that laboratory work is an important part of introductory science courses, there is scant evidence for the relationship between laboratory work and student learning, particularly at the college level. This work reports the quantitative component of a mixed-methods study of the effect of cooperative problem-based laboratory instruction on problem-solving ability and regulatory metacognitive activity. For this purpose, a previously reported assessment, IMMEX, was used. Mixed-methods evidence suggests that students in such an environment showed improved problem-solving skills and strategies, and showed increased regulation of metacognitive skills, despite a lack of explicit instruction. This work puts forth the proposal that providing an environment that is conducive to social interaction and reflection allows students to develop these desirable skills. (Contains 5 tables and 1 figure.)

Current views on metacognition consider it a fundamental factor in learning and problem-solving which in turn has led to interest in creating learning experiences conducive to developing its use. This paper reports on the effectiveness of a collaborative intervention in promoting college general chemistry students' awareness and use of metacognition. The intervention starts with a cognitive imbalance experience as a trigger for metacognitive reflection, which is then followed by reflective prompting and peer interaction. A quasi-experimental control and treatment design with 537 and 464 participants, respectively, was implemented. Assessment of metacognition was accomplished by using a multi-method instrument that consists of a self-report (Metacognitive Activities Inventory, MCAI) and a concurrent, web-based tool (Interactive Multimedia Exercises, IMMEX). IMMEX has been shown to allow rapid classification of problem solvers according to their regulatory metacognitive skills. Compared to the control group, the treatment group showed a significant increase in metacognition awareness, as evidenced by the MCAI, increased ability in solving non-algorithmic chemistry problems of higher difficulty, and with a higher per cent correctness (IMMEX). These findings are consistent with an overall increase in the use of regulatory metacognitive skills by the treatment group. We propose that the meaningful, purposeful social interaction and the reflective prompting instantiated by the intervention act as promoters of metacognition development. It is of particular relevance that these factors are not exclusive to the intervention employed here and can be embedded by practitioners in their instruction. (Contains 1 note, 1 figure and 5 tables.)

Most educators and scientists would agree that science laboratory instruction has the potential of developing science practices fundamental to achieving scientific literacy. However, there is scant evidence to support that this potential is realized, particularly in tertiary level education. This paper reports qualitative results from a sequential explanatory mixed methods study aimed at investigating the effectiveness of a college, cooperative, project-based General Chemistry Laboratory in promoting student learning. Quantitative findings showed that students in this programme increased their ability and metacognitive strategies in solving online ill-structured chemistry problems. For the current study, we used a phenomenological approach to investigate the essence of students' experiences in this learning environment. Eleven participants volunteered to take part in in-depth, open-ended interviews. Phenomenological data reduction, analysis and interpretation produced an outcome space composed of three dimensions (Affective Response, Understanding of the Learning Experience, and Strategic Response). The need to "take charge of learning" emerged as the interconnecting factor bringing cohesiveness to the experience. These findings are consistent with the previous quantitative report. Additionally, they support the notion that immersion in a lab environment appropriately designed to constantly challenge students to think through problems and figure out solutions does indeed promote metacognition and problem solving skills. Situating learning in this context facilitates meaningful self-discovery and internalization of strategies as opposed to externally introducing them. We believe that these findings contribute evidence of the relationship between experiences in the laboratory and student effective learning and can inform and guide curricular development. (Contains 2 figures and 1 table.)

The importance of distillation in the separation field prompts the inclusion of distillation experiments in the chemical engineering curricula. This work describes the performance of an Oldershaw column in the rectification of a cyclohexane/n-heptane mixture. Total reflux distillation, continuous rectification under partial reflux, and batch rectification at constant reflux were studied. With this experimental work, students practice several relevant distillation concepts, and also the use of chemical engineering simulation software.

Research in general chemistry laboratory instruction has rarely focused on the impact of the learning environment on the graduate teaching assistants (GTAs). We decided to investigate the effect that facilitating a well established cooperative problem-based chemistry laboratory has on GTAs' epistemological and metacognitive development, and how this may translate into their scientific professional growth. Thirteen new GTAs underwent a day and a half teaching training complemented by weekly staff meetings. They were interviewed after their first semester as GTAs, and the data collected were analyzed utilizing a phenomenological approach. Three dimensions that describe the experience lived by the participants emerged from the analysis: affective engagement, metacognitive engagement, and epistemological reflection. The last two offer a rich description of how the laboratory context promotes GTAs' metacognitive and epistemological development, whereas the former provides understanding about the motivation driving their intellectual engagement. Considering the role of metacognition in research, and that personal epistemology is strongly tied to identity development, and that it shapes expectations and ways of learning, it is our contention that appropriate teaching experiences may contribute to better prepare graduate students for their journey in becoming scientists and to embark on successful research. (Contains 1 table and 2 figures.)

The influence of metacognition on learning and problem solving has been demonstrated, and it is becoming increasingly clear that promoting metacognitive activity can produce substantial improvements in problem solving and learning in chemistry. This article reports the development and validation of an instrument designed to evaluate students' metacognitive skillfulness in solving chemistry problems: the Metacognitive Activities Inventory (MCAI). This inventory may be used as a diagnostic tool to inform the implementation of interventions, as well as to evaluate the effect of changes in instruction. Reliability of the MCAI was measured in terms of internal consistency, and validity was examined in two dimensions: face validity, and construct validity. Evidence reported in this study indicates that the MCAI is a robust, reliable, and valid instrument. (Contains 1 figure, 4 tables and 2 notes.)

17 selected flavones derivatives, flavonoids, were analyzed through a systematic B3LYP∕6-311++G** computational study with the aim of understanding the molecular factors that determine their structural and energetic properties in gas phase. Flavonoids were selected in a systematic way to infer the effect of the number and relative positions of hydroxyl groups on molecular properties. Different conformers for each flavonoid were analyzed and the strength and topology of the intramolecular hydrogen bonds studied through the computation of the corresponding torsional profiles. Atoms in a Molecule, and Natural Bond Orbital methodology was applied to the analysis of charge distribution along the studied molecules, and the intramolecular hydrogen bonds. Molecular shapes were studied through full geometry optimization, and the position of the catechol ring analyzed through dihedral scans.

Metacognition is fundamental in achieving understanding of chemistry and developing of problem solving skills. This paper describes an across-method-and-time instrument designed to assess the use of metacognition in chemistry problem solving. This multi method instrument combines a self report, namely the Metacognitive Activities Inventory (MCA-I), with a concurrent automated online instrument, Interactive MultiMedia Exercises (IMMEX). IMMEX presents participants with ill defined problems and collects students' actions as they navigate the problem space. Artificial neural networks and hidden Markov modeling applied to the data collected with IMMEX produce two assessment parameters: the "strategy state", which is related to the metacognitive qualities of the solution path employed, and the "ability" which is a measure of the problem difficulty students can properly handle. The ability values are significantly correlated with the MCA-I scores, and groups of students who performed using more metacognitive state strategies had significantly higher mean MCA-I values than those using fewer metacognitive strategies. This evidence is indicative of convergence between the methods. This instrument can be used diagnostically to guide the implementation of interventions to promote the use of metacognition; it takes little instructional time, is readily available and allows for the assessment of large cohorts. (Contains 3 tables and 4 figures.)

Traditional approaches to the development of integrated circuits involve the use and/or manufacture of toxic materials that have a potential environmental impact. An extensive research has been done to design environmentally benign synthetic polymers containing nucleic acid bases, which can be used to enhance the photoresistor technologies. Water soluble, environmentally benign photopolymers of 1-(4-vinylbenzyl) thymine (VBT) and vinylphenyl sufonate (VPS) undergo a photodimerization reaction when exposed to low levels of ultraviolet irradiation leading to an immobilization of the copolymer on a variety of substrates. Plackett-Burman design (PBD) and central composite design (CCD) were applied to identify the significant factors influencing the polymer crosslinking and dye adsorption processes, which are relevant in the fabrication of copolymer films for potential photoresist use. The PBD results assigned a maximum absorption signal of 0.67, while optimal conditions obtained in this experiment following the CCD method predictions provided a response of 0.83 ± 0.03, being a solid foundation for further use of this methodology in the production of potential photoresistors. The pH effect was relevant for low concentrations but not significant for higher concentrations. To the best of our knowledge, this was the first report applying statistical experimental designs to optimize the crosslinking of thymine-based polymers.