La construcción de nociones básicas de química en ciencias agropecuarias : el caso de "efectos electrónicos en las moléculas"

La comprensión de la relación estructura-propiedades es fundamental en el estudio de química en las ciencias agropecuarias. En ese sentido y a partir de las dificultades observadas en los alumnos para la aplicación de ese núcleo conceptual, se identificó la noción básica efectos electrónicos en las moléculas y se planteó la investigación de su construcción conceptual. Se utilizaron en este estudio dos instrumentos metodológicos: cuestionario y entrevista semiestructurada con modalidad clínica. Se detectaron ciertos obstáculos epistemológicos en la argumentación de los alumnos. Éstos fueron: la tendencia a la generalización, el empirismo inmediato y los modelos simplistas, que actuarían bloqueando el pensamiento profundo. Concluímos que el aprendizaje de la noción efectos electrónicos en las moléculas requiere del despliegue de toda su complejidad epistemológica.The understanding of the structure-properties relation is of great importance in the chemistry study in Agricultural Sciences. In this sense, starting from the difficulties found in students when applying this conceptual nucleus, we identified the basic notion molecular electronic effects and proposed the research of its conceptual construction. In this study, two methodologies were applied: questionnaire and clinical semistructured interview. The answers and the arguments of the students showed certain epistemological obstacles. These were: the tendency to generalization, the immediate empiricism and the simplistic models that would act blocking the profound thoughts. We concluded that the learning of the notion: molecular electronic effects needs to display its overall epistemological complexity

Carbapenem-resistant Enterobacteriaceae dispersal from sinks is linked to drain position and drainage rates in a laboratory model system.

BACKGROUND: Hospital sinks, waste traps and drains can harbour carbapenem-resistant Enterobacteriaceae (CRE). AIM: To investigate the dispersal of CRE from sinks in which water delivered from the tap flows directly into the drain and from clinical handwash basins with the drain at the rear. The effect of fast and slow drainage rates was also assessed. METHODS: Waste traps, known to be colonized with CRE, were taken from a hospital and installed within a model laboratory system. New waste traps were also installed and artificially inoculated with CRE. The potential for bacteria to be dispersed from sinks was assessed using cyclone air samplers and/or settle plates. FINDINGS: When the waste traps were artificially contaminated and CRE colonization was confined to the waste trap water, significantly fewer bacteria were dispersed from sinks that drained quickly (P = 0.004) and/or from rear-draining sinks (P = 0.002). When the waste traps were naturally contaminated and CRE colonized the trap, pipework and drain, there was significant interaction between sink drainage and position of the drain (P < 0.001). When drainage was slow, dispersal from rear-draining sinks was almost 30-fold less than from sinks with the drain underneath the tap (P < 0.001). When drainage was fast, rear-draining sinks again released comparatively fewer CRE, although, in this case, the difference was not statistically significant (P = 0.7). Contaminated splashes travelled up to 1 m from the sink. CONCLUSION: Slow drainage rates and sink designs with the drain directly underneath the tap increase the risk of CRE present in waste traps and drains contaminating the ward environment

The 4q25 variant rs13143308T links risk of atrial fibrillation to defective calcium homeostasis

Aims: Single nucleotide polymorphisms on chromosome 4q25 have been associated with risk of atrial fibrillation (AF) but the exiguous knowledge of the mechanistic links between these risk variants and underlying electrophysiological alterations hampers their clinical utility. Here, we here tested the hypothesis that 4q25 risk variants cause alterations in the intracellular calcium homeostasis that predispose to spontaneous electrical activity. Methods and results: Western blotting, confocal calcium imaging, and patch-clamp techniques were used to identify mechanisms linking the 4q25 risk variants rs2200733T and rs13143308T to defects in the calcium homeostasis in human atrial myocytes. Our findings revealed that the rs13143308T variant was more frequent in patients with AF and that myocytes from carriers of this variant had a significantly higher density of calcium sparks (14.1±4.5 vs. 3.1±1.3 events/min, p¿=¿0.02), frequency of transient inward (ITI) currents (1.33±0.24 vs. 0.26±0.09 events/min, p¿<¿0.001) and incidence of spontaneous membrane depolarizations (1.22±0.26 vs. 0.56±0.17 events/min, p¿=¿0.001) than myocytes from patients with the normal rs13143308G variant. These alterations were linked to higher sarcoplasmic reticulum calcium loading (10.2±1.4 vs. 7.3±0.5amol/pF, p¿=¿0.01), SERCA2 expression (1.37±0.13 fold, p¿=¿0.03) and RyR2 phosphorylation at s2808 (0.67±0.08 vs. 0.47±0.03, p¿=¿0.01) but not at s2814 (0.28±0.14 vs. 0.31±0.14, p¿=¿0.61) in patients carrying the rs13143308T risk variant. Furthermore, the presence of a risk variant or AF independently increased the ITI frequency and the increase in the ITI frequency observed in carriers of the risk variants was exacerbated in those with AF. By contrast, the presence of a risk variant did not affect the amplitude or properties of the L-type calcium current in patients with or without AF. Conclusions: We here identify the 4q25 variant rs13143308T as a genetic risk marker for AF, specifically associated with excessive calcium release and spontaneous electrical activity linked to increased SERCA2 expression and RyR2 phosphorylationThis work was supported by multi-centric grants from Centro Nacional de Investigaciones Cardiovasculares [CNIC-2009-08 to L.H.-M. and D.F.]; a grant from Fundacio´ Marato´ TV3 [2015-20-30 to L.H.-M.]; and grants from the Spanish Ministry of Economy and Competition [SAF2014-58286-C2-1-R to L.H.-M.] and [DPI2013-44584-R to R.B.]; and from the Spanish Ministry of Health and Consume, Instituto de Salud Carlos III, Red de Investigacio´n Cardiovascular [RD12/0042/0002] and CIBERCV to J.C., and from Fondo Europeo de Desarrollo Regional (FEDER)

Nanomedicine: Application Areas and Development Prospects

Nanotechnology, along with related concepts such as nanomaterials, nanostructures and nanoparticles, has become a priority area for scientific research and technological development. Nanotechnology, i.e., the creation and utilization of materials and devices at nanometer scale, already has multiple applications in electronics and other fields. However, the greatest expectations are for its application in biotechnology and health, with the direct impact these could have on the quality of health in future societies. The emerging discipline of nanomedicine brings nanotechnology and medicine together in order to develop novel therapies and improve existing treatments. In nanomedicine, atoms and molecules are manipulated to produce nanostructures of the same size as biomolecules for interaction with human cells. This procedure offers a range of new solutions for diagnoses and “smart” treatments by stimulating the body’s own repair mechanisms. It will enhance the early diagnosis and treatment of diseases such as cancer, diabetes, Alzheimer’s, Parkinson’s and cardiovascular diseases. Preventive medicine may then become a reality

COVAD survey 2 long-term outcomes: unmet need and protocol

Vaccine hesitancy is considered a major barrier to achieving herd immunity against COVID-19. While multiple alternative and synergistic approaches including heterologous vaccination, booster doses, and antiviral drugs have been developed, equitable vaccine uptake remains the foremost strategy to manage pandemic. Although none of the currently approved vaccines are live-attenuated, several reports of disease flares, waning protection, and acute-onset syndromes have emerged as short-term adverse events after vaccination. Hence, scientific literature falls short when discussing potential long-term effects in vulnerable cohorts. The COVAD-2 survey follows on from the baseline COVAD-1 survey with the aim to collect patient-reported data on the long-term safety and tolerability of COVID-19 vaccines in immune modulation. The e-survey has been extensively pilot-tested and validated with translations into multiple languages. Anticipated results will help improve vaccination efforts and reduce the imminent risks of COVID-19 infection, especially in understudied vulnerable groups

A new class of glycomimetic drugs to prevent free fatty acid-induced endothelial dysfunction

Background: Carbohydrates play a major role in cell signaling in many biological processes. We have developed a set of glycomimetic drugs that mimic the structure of carbohydrates and represent a novel source of therapeutics for endothelial dysfunction, a key initiating factor in cardiovascular complications. Purpose: Our objective was to determine the protective effects of small molecule glycomimetics against free fatty acid­induced endothelial dysfunction, focusing on nitric oxide (NO) and oxidative stress pathways. Methods: Four glycomimetics were synthesized by the stepwise transformation of 2,5­dihydroxybenzoic acid to a range of 2,5­substituted benzoic acid derivatives, incorporating the key sulfate groups to mimic the interactions of heparan sulfate. Endothelial function was assessed using acetylcholine­induced, endotheliumdependent relaxation in mouse thoracic aortic rings using wire myography. Human umbilical vein endothelial cell (HUVEC) behavior was evaluated in the presence or absence of the free fatty acid, palmitate, with or without glycomimetics (1µM). DAF­2 and H2DCF­DA assays were used to determine nitric oxide (NO) and reactive oxygen species (ROS) production, respectively. Lipid peroxidation colorimetric and antioxidant enzyme activity assays were also carried out. RT­PCR and western blotting were utilized to measure Akt, eNOS, Nrf­2, NQO­1 and HO­1 expression. Results: Ex vivo endothelium­dependent relaxation was significantly improved by the glycomimetics under palmitate­induced oxidative stress. In vitro studies showed that the glycomimetics protected HUVECs against the palmitate­induced oxidative stress and enhanced NO production. We demonstrate that the protective effects of pre­incubation with glycomimetics occurred via upregulation of Akt/eNOS signaling, activation of the Nrf2/ARE pathway, and suppression of ROS­induced lipid peroxidation. Conclusion: We have developed a novel set of small molecule glycomimetics that protect against free fatty acidinduced endothelial dysfunction and thus, represent a new category of therapeutic drugs to target endothelial damage, the first line of defense against cardiovascular disease