Nanoreinforcement as a strategy to improve physical properties of biodegradable composite films based on biopolymers

Food packaging is evolving from inert plastic to renewable biopolymer film that acts as barrier against gases, light radiation, and microorganisms, reducing food waste without environmental damage. Distinct starting systems were selected to prepare films: single polymer matrix, blend of polymers, cross-linked polymers, and emulsion-based matrix. The blend of polymers was one of the best approaches to improve mechanical and barrier properties of films, especially when one of the polymers was pectin, gelatin or xanthan gum. These polymers can form a gel and increase the viscosity of the starting systems leading to a more elastic matrix. Although some of these films showed potential to replace plastic materials, their physical properties were poor compared to plastics. Thus, several strategies were used to strengthen matrix building block connections or interactions between nanoreiforcement and matrix compounds with the aim of improving physical properties. Among metal oxides, TiO2, ZnO, CaO, and MgO were the most studied, alone or in combinations with other reinforcements. Natural fillers, like chitosan and cellulose nanofibers were also added to improve the biopolymer's performance. Several of these systems successfully extended the shelf life of food systems by retarding spoilage, showing great potential to improve food quality and reduce waste. However, most of the studies were carried out on a laboratory scale and it would be necessary to explore the feasibility of producing these films on an industrial scale.Fil: Hoyos Merlano, Nurys Tatiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Borroni, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Rodríguez Batiller, María Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Candal, Roberto Jorge. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Herrera, Maria Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentin

La formation procédurale par simulation au pré-externat pour réduire l’anxiété et renforcer la confiance des étudiants par rapport à leurs habiletés techniques

Introduction: Pre-clerkship procedural skills training is not yet a standard across Canadian medical school curricula, resulting in limited exposure to procedures upon entering clerkship. While simulated skills training has been documented in the literature to improve performance in technical ability, anxiety and confidence have yet to be investigated despite their documented impact on performance and learning. This study therefore aims to evaluate the effect of pre-clerkship procedural skills training on medical student anxiety and confidence. Methods: A procedural skills training program was designed based on an evidence-based near-peer, flipped classroom model of education. Ninety-two second-year medical students volunteered for the study. Fifty-six were randomized to the training group, and 36 were randomized to the control group. Students in the training group attended seven procedural skills tutorials over seven months. The control group represented the average medical school student without standardized procedural training. Student anxiety and confidence were assessed at the beginning and end of the program using the State Trait Anxiety Inventory and Confidence Questionnaires. Results: Students who participated in the procedural skills program demonstrated greater reductions in their state anxiety and greater improvements in confidence compared to the control group. Conclusion: Longitudinal procedural skills training in the simulation setting has demonstrated improvements in anxiety and confidence among pre-clerkship medical students. These added benefits to training have the potential to ease medical students’ transition into clerkship, while also contributing to a safer and more effective clinical experience. Therefore, future integration of standardized pre-clerkship procedural skills training within medical school curricula should be considered.Introduction : Les cursus de pré-externat des facultés de médecine canadiennes ne prévoient pas systématiquement de formation sur les habiletés techniques avant, si bien qu’à leur arrivée à l’externat, les étudiants ont une exposition limitée aux gestes techniques. Tandis que l’amélioration des aptitudes techniques par la simulation est bien documentée, il n’y a aucune étude sur l’effet de ces simulations sur l’anxiété et la confiance malgré leur impact avéré sur la performance et l’apprentissage. Cette étude vise donc à évaluer l’effet d’une formation sur les habiletés techniques au pré-externat sur l’anxiété et la confiance des étudiants en médecine. Méthodes : Une formation sur les habiletés techniques a été conçue sur la base d’un modèle d’enseignement fondé sur les données probantes, par les quasi-pairs suivant une approche de classe inversée. Quatre-vingt-douze étudiants en deuxième année de médecine ont participé à l’étude sur une base volontaire. Cinquante-six d’entre eux ont été répartis au hasard dans le groupe qui devait recevoir la formation, et 36 dans le groupe contrôle. Les étudiants du groupe qui a reçu la formation ont assisté à sept tutoriels étalés sur une période de sept mois. Le groupe témoin représentait l’étudiant en médecine moyen sans formation normalisée axée sur les habiletés techniques. L’anxiété et la confiance des étudiants ont été évaluées au début et à la fin du programme à l’aide du questionnaire State Trait Anxiety Inventory (questionnaire sur l’anxiété chronique et réactionnelle) et d’un questionnaire sur la confiance. Résultats : Chez les étudiants qui ont participé au programme de formation sur les habiletés techniques, la baisse de l’anxiété et l’amélioration de la confiance en soi ont été plus importantes que chez les étudiants du groupe contrôle. Conclusion : La formation longitudinale axée sur les habiletés techniques en contexte de simulation a eu des effets positifs en ce qui concerne l’anxiété et la confiance chez les étudiants en médecine au pré-externat. La formation offre l’avantage supplémentaire de faciliter la transition des étudiants en médecine vers l’externat, tout en contribuant à rendre l’expérience clinique plus sûre et plus efficace. Il serait donc intéressant pour les facultés de médecine d’intégrer dans le cursus une formation normalisée axée sur les habiletés techniques au pré-externat

Définir les compétences procédurales essentielles dans la formation médicale canadienne de premier cycle

Introduction: We conducted a national survey to characterize current Canadian procedural skills training in Undergraduate Medical Education (UGME). The goals were to identify the most important procedures students should know upon graduation and assess clinician-educator perceptions regarding implementation of a pre-clerkship procedural program. Methods: We distributed the survey to physician-educators across Canada’s 17 medical schools. Respondents were directed to an individualized survey that collected demographic data, physician-educator responses on essential procedural skills, as well as physician-educator opinions on the value of a pre-clerkship procedural training program. Results: The response rate for this survey was 21% (42 out of 201 distributed surveys were completed). The top 10 most important procedures identified by physician-educators included IV Access, Airway Management, Local anesthesia/field block, Casting, Spontaneous Vaginal Delivery, Testing for STIs, Phlebotomy, Suturing of Lacerations, Nasogastric Tube Insertion, and Venipuncture. Physician-educators supported a pre-clerkship procedural program. Conclusions: Identifying the most crucial procedural skills is the first step in implementing a competency-based procedural skills training program for Canadian medical students. With the list of essential skills, and the support for physician-educators in developing a pre-clerkship procedural skills curriculum, hopefully there can be future development of formalized curricula.Contexte: Nous avons mené un sondage à l’échelle nationale pour caractériser les compétences procédurales canadiennes dans la formation médicale de premier cycle. L’objectif était de reconnaître les plus importantes procédures que les étudiants devaient connaître à la fin de leur formation et d’évaluer les perceptions des cliniciens éducateurs au sujet de la mise en œuvre de leur programme procédural avant les stages. Méthodes : Nous avons distribué le sondage à des médecins éducateurs dans les 17 écoles de médecine du Canada. Les répondants ont été dirigés vers un sondage individualisé qui recueillait les données démographiques, les réponses des médecins éducateurs sur les compétences procédurales essentielles, ainsi que les opinions des médecins éducateurs sur la valeur du programme de formation procédurale avant les stages. Résultats : Le taux de réponse à ce sondage a été de 21 % (42 des 201 sondages distribués ont été remplis). Les dix plus importantes procédures recensées par les médecins éducateurs comprenaient l’accès IV, l’assistance respiratoire, le bloc anesthésie locale/champ, le moulage de plâtre, l’accouchement spontané par voie vaginale, les tests d’ITS, la phlébotomie, la suture des lacérations, l’insertion d’une sonde nasogastrique et la ponction veineuse. Les médecins éducateurs soutenaient un programme procédural avant les stages. Conclusions : Établir les compétences procédurales les plus essentielles représente la première étape dans la mise en œuvre d’un programme de formation dans les compétences procédurales fondé sur les compétences pour les étudiants canadiens en médecine. Avec la liste de compétences essentielles et le soutien des médecins éducateurs dans le développement d’un programme de compétences procédurales avant les stages, nous espérons qu’un programme structuré sera élaboré

Rationale for combination of therapeutic antibodies targeting tumor cells and immune checkpoint receptors: Harnessing innate and adaptive immunity through IgG1 isotype immune effector stimulation

Immunoglobulin (Ig) G1 antibodies stimulate antibody-dependent cell-mediated cytotoxicity (ADCC). Cetuximab, an IgG1 isotype monoclonal antibody, is a standard-of-care treatment for locally advanced and recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) and metastatic colorectal cancer (CRC). Here we review evidence regarding the clinical relevance of cetuximab-mediated ADCC and other immune functions and provide a biological rationale concerning why this property positions cetuximab as an ideal partner for immune checkpoint inhibitors (ICIs) and other emerging immunotherapies. We performed a nonsystematic review of available preclinical and clinical data involving cetuximab-mediated immune activity and combination approaches of cetuximab with other immunotherapies, including ICIs, in SCCHN and CRC. Indeed, cetuximab mediates ADCC activity in the intratumoral space and primes adaptive and innate cellular immunity. However, counterregulatory mechanisms may lead to immunosuppressive feedback loops. Accordingly, there is a strong rationale for combining ICIs with cetuximab for the treatment of advanced tumors, as targeting CTLA-4, PD-1, and PD-L1 can ostensibly overcome these immunosuppressive counter-mechanisms in the tumor microenvironment. Moreover, combining ICIs (or other immunotherapies) with cetuximab is a promising strategy for boosting immune response and enhancing response rates and durability of response. Cetuximab immune activity—including, but not limited to, ADCC—provides a strong rationale for its combination with ICIs or other immunotherapies to synergistically and fully mobilize the adaptive and innate immunity against tumor cells. Ongoing prospective studies will evaluate the clinical effect of these combination regimens and their immune effect in CRC and SCCHN and in other indications

Osteoporotic vertebral fracture simulating a spinal tumor: A case report

Vertebral fractures are a frequent entity, mainly in the thoracolumbar and lumbar spine. In some circumstances the differential diagnosis of vertebral injuries can confuse the physician, since the difference between an osteoporotic vertebral fracture and a fracture secondary to a tumor is not clear. We report the case of a patient with osteoporotic vertebral fracture simulating a spinal tumor, handled by our department of neurosurgery as illustrative experience to guide the approach in those cases, in which the definitive diagnosis is crucial for therapeutic decision making

The Renin Angiotensin System (RAS) mediates bifunctional growth regulation in melanoma and is a novel target for therapeutic intervention

Despite emergence of new systemic therapies, metastatic melanoma remains a challenging and often fatal form of skin cancer. The renin–angiotensin system (RAS) is a major physiological regulatory pathway controlling salt–water equilibrium, intravascular volume and blood pressure. Biological effects of the RAS are mediated by the vasoactive hormone angiotensin II (AngII) via two receptor subtypes, AT1R (encoded by AGTR1) and AT2R (encoded by AGTR2). We report decreasing expression and increasing CpG island methylation of AGTR1 in metastatic versus primary melanoma and detection in serum of methylated genomic DNA from the AGTR1 CpG island in metastatic melanoma implying that AGTR1 encodes a tumour suppressor function in melanoma. Consistent with this hypothesis, antagonism of AT1R using losartan or shRNA-mediated knockdown in melanoma cell lines expressing AGTR1 resulted in acquisition of the ability to proliferate in serum-free conditions. Conversely, ectopic expression of AGTR1 in cell lines lacking endogenous expression inhibits proliferation irrespective of the presence of AngII implying a ligand-independent suppressor function for AT1R. Treatment of melanoma cell lines expressing endogenous AT2R with either AngII or the AT2R-selective agonist Y6AII induces proliferation in serum-free conditions whereas the AT2R-specific antagonists PD123319 and EMA401 inhibit melanoma growth and angiogenesis and potentiate inhibitors of BRAF and MEK in cells with BRAF V600 mutations. Our results demonstrate that the RAS has both oncogenic and tumour suppressor functions in melanoma. Pharmacological inhibition of AT2R may provide therapeutic opportunities in melanomas expressing this receptor and AGTR1 CpG island methylation in serum may serve as a novel biomarker of metastatic melanoma

Aulas develadas 3: La práctica, con investigación, se cambia

Este tercer libro de la colección “Aulas develadas: La práctica, con investigación, se cambia”, producto de las investigaciones de aula adelantadas por docentes de la Universidad del Norte, con el apoyo del Centro para la Excelencia Docente (CEDU) en el programa Círculo de Escritura, lo componen seis capítulos que recopilan los resultados de trabajos realizados por docentes de las áreas Ciencia política y Relaciones internacionales, Matemáticas, Psicología e Ingeniería. Confiamos en que los hallazgos que aquí se presentan sean de interés para los lectores y puedan ser compartidos de manera amplia entre distintos públicos

Comportamiento e impacto económico de las exportaciones de la industria pesquera en Cartagena para el periodo 1985 - 1995 y perspectivas

Tesis (Economista).--Universidad de Cartagena. Facultad de Ciencias Económicas. Programa de Economía, 1996.El presente estudio tiene por objeto determinar cual ha sido la incidencia de las exportaciones pesqueras de la ciudad de cartagena en la economía regional, su evolución y sus posibilidades en el mercado internacional