Patricio Rodríguez

Teaching science with mobile computer supported collaborative learning (MCSCL)

Effectively incorporating technology into the classroom is a great challenge faced by schools today. In this article, we propose a mobile computer supported collaborative learning (MCSCL) system to support high school teachers with wirelessly networked handheld computers. This system promotes student collaboration and constructivism, without losing face-to-face contact. The MCSCL system was tested during a five week experience in a high school physics class. We observed both its qualitative and quantitative impact. Students and teachers responded very favorably to the system, and the experience also had a strong social impact outside the classroom. The MCSCL system provided a highly motivating learning environment that changed classroom dynamics and promoted collaboration between students. We obtained statistically significant results showing that the environment created by combining the teachers instruction with the MSCSL system enabled the students to construct new knowledge based upon the previous knowledge provided by the teacher.

ICT for education: a conceptual framework for the sustainable adoption of technology-enhanced learning environments in schools

Currently, the use of information and communication technologies (ICT) in education does not conclusively demonstrate significant effects on learning. However, not all ICT usage models are designed to affect student outcomes. Therefore, to accurately study the impact of ICT, the concept of an educational programme supported by ICT must first be defined. The authors propose the ICT for Education (ICT4E) programme, an evidence-based framework to determine a model’s ability to produce improvements before having to evaluate its results. The framework has four components: implementation, intervention, transference and total cost. Based on an explicit definition of the outcomes pursued by a given programme, this framework supports the design of its activities to promote sustainable changes in pedagogical practices in schools and calculate the programme’s total cost. The authors illustrate this with a programme implemented in six countries. In Chile, the ICT4E programme forms part of the policy for educational technology, evaluating the effectiveness and scalability of such initiatives.

Ligand-dependent structural changes and limited proteolysis of Escherichia coli phosphofructokinase-2.

Binding of MgATP to the allosteric site of phosphofructokinase-2 promotes a dimer to tetramer conversion. In the presence of Fru-6-P the enzyme remains as a dimer. Limited proteolysis in the presence of MgATP completely protects the enzyme against inactivation and cleavage, while Fru-6-P provides a partial protection. A 28-kDa proteolytic fragment containing the N-terminus of the protein is inactive, but retains the ability to bind Fru-6-P and the allosteric effector MgATP. The fragment remains as a dimer but does not form a tetramer in the presence of MgATP. The results suggest major conformational changes of the enzyme upon ligand binding that confer a higher degree of compactness to the monomers in the dimer and in the tetramer, demonstrate the presence of the active and allosteric sites in this N-terminus fragment, and stress the importance of the C-terminus region of the protein for catalytic activity and ligand-induced oligomerization.

Tracheal hamartoma: pericardial flap replacement of membranous tracheal wall

We presented a rare case of large tracheal hamartoma in a 14-year-old boy and its management with a novel technique of reparation with pericardium of entire membranous portion of the trachea, after the failure of more conservative approaches like bronchoscopic resection and stenting. We remark the advantages of autologous material instead of prosthetic material.

Cirugía pulmonar en tuberculosis

Background: Surgical treatment for pulmonary tuberculosis is mainly limited to the management of sequelae such as bronchiectasis, hemoptysis and brochopleural fistulae. Aim: To review the data of patients who underwent surgical treatment for pulmonary tuberculosis. Material and methods: Retrospective review of 33 patients aged 18 to 73 years (24 males) who underwent lung resection surgery for the management of pulmonary tuberculosis. Follow-up data were obtained from outpatient visit records and registries of the national tuberculosis program. Results: The reasons to perform surgery were the following: fifteen for hemoptysis, nine for lung destruction and nine for an active and multiresistant disease. No patient died in the postoperative period. The morbidity observed included empyema (n =5), pneumothorax (n =2), bronchopleural fistula (n =2) and hemothorax (n =2). At six months of follow up, six of the nine patients with active tuberculosis had negative acid-fast bacilli on sputum smear. Two of these patients died, one due to respiratory failure and another by an unrelated cause. Both dead patients had negative acidfast bacilli on sputum smear. Conclusions: Surgery in pulmonary tuberculosis has a high rate of complications but may be useful in selected patients (Rev Med Chile 2009; 137: 234-9).

Structural and functional roles of Cys-238 and Cys-295 in Escherichia coli phosphofructokinase-2.

Modification of Escherichia coli phosphofructokinase-2 (Pfk-2) with pyrene maleimide (PM) results in a rapid inactivation of the enzyme. The loss of enzyme activity correlates with the incorporation of 2 mol of PM/mol of subunit and the concomitant dissociation of the dimeric enzyme. The two modified residues were identified as Cys-238 and Cys-295. In the presence of the negative allosteric effector, MgATP, Cys-238 was the only modified cysteine residue. Kinetic characterization of the Cys-238-labelled Pfk-2 indicates that the enzyme is fully active, with the kinetic constants ( K(m), kcat) being almost identical to the ones obtained for the native enzyme. The modified enzyme is a monomer in the absence of ligands and, like the native enzyme, behaves as a tetramer in the presence of the nucleotide. However, in the presence of fructose-6-phosphate (fru-6-P) and ATP(-4), the enzyme behaves as a dimer, suggesting that the monomers undergo re-association in the presence of the substrates and that the active species is a dimer. Modification of Pfk-2 with eosin-5-maleimide (EM) results in the labelling of Cys-295. This modified enzyme is inactive and is not able to bind to the allosteric effector, remaining as a dimer in its presence. Nonetheless, Cys-295-labelled Pfk-2 is able to bind to the substrate fru-6-P in an hyperbolic fashion with a K(d) value that is 6-fold higher than the one determined for the native enzyme. These are the first residues to be implicated in the activity and/or structure of the Pfk-2.

Left intercostal aneurysm fistulised to azygos vein as a late complication of thoracic trauma

2011;39:276Eur J Cardiothorac Surg Roberto González, Raimundo Santolaya, Rafael Prats and Patricio Rodriguez trauma Left intercostal aneurysm fistulised to azygos vein as a late complication of thoracic This information is current as of October 4, 2011 http://ejcts.ctsnetjournals.org/cgi/content/full/39/2/276 located on the World Wide Web at: The online version of this article, along with updated information and services, is

Uso del dispositivo de asistencia respiratoria Novalung® como puente a trasplante pulmonar: Caso clínico

Devices such as Novalung ® can be used as a bridge to lung transplantation while waiting for a suitable donor. We report a 50 year-old male with a terminal pulmonary fibrosis and candidate for lung transplantation. He was admitted to the hospital due to a severe deterioration of his respiratory condition, with the presence of severe respiratory acidosis despite conventional invasive respiratory support. Respiratory support with Novalung ® was started, resulting in a progressive reduction of pCO 2 , that became normal ten hours after the installation of the device. Five

Leiomiosarcoma primario de mediastino que compromete el sistema de la vena cava superior: Resección quirúrgica asociada a reconstrucción venosa

Primary leiomyosarcoma of the mediastinum involving the superior vena cava system. Surgical resection and venous reconstruction Mediastinal tumors have multiple presentation forms and various pathological origins. Sometimes they reach a large size and can involve the system of superior vena cava by compression or infi ltration. We present a 48 year old man admited for dyspnea, headache and palpitations in decubitus, for the last two months. The X-ray and chest computed tomography showed an anterior mediastinal tumor and the tru-cut pathological study concluded leiomyosarcoma. He underwent surgical treatment; the tumor compromised the system of the superior vena cava and was resected with ligation and resection the left brachiocephalic trunk. Part of the superior vena cava was reconstructed with autologous pericardium. The right phrenic nerve was surrounded by the tumor mass and was resected in block. The patient recovered satisfactorily and was discharged on the eleventh day post surgery. The histopathologic study of the surgical specimen confi rmed a leiomyosarcoma G2 (3,100 gr). Full adjuvant radiotherapy was done. At 15 months after surgery the patient is in good condition without evidence of recurrence or superior vena cava syndrome.

Interaction of Protein Kinase Ac from Ascaris suum with Proteins and Peptides: Comparison with the Mammalian Enzyme

Protein kinases belong to a single large family of proteins (Hanks et al., 1988) and exhibit considerable similarity in primary and tertiary structure. While they are highly specific for ATP as phosphate donor (only a small minority uses GTP as an alternative), their limited in vitro specificity for protein substrates is remarkable with regard to the specialized functions of protein kinases in signal transduction, and cellular and metabolic regulation. Most obvious specificities attributed to certain subfamilies concern their ability to catalyze the formation of phosphate esters of either aliphatic or aromatic amino acid residues (or both) and the requirement for given recognition sites. Typically, these recognition sites are degenerate and comprise only a few amino acids in the vicinity of a serine, threonine or tyrosine residue, thus hardly providing elaborate tools of molecular recognition.