Estrategias de difusión de nanociencia y nanotecnología en distintos sectores de la sociedad en Argentina

Las nuevas tecnologías implican una interacción compleja de factores técnicos y sociales. La innovación que produce la Nanotecnología y sus beneficios en la sociedad es parcialmente comprendida; ambos, innovación y beneficios constituyen temas valiosos para informar y discutir. La formación académica y trayectoria científica de docentes e investigadores de universidades y del sistema científico, es lo que permite implementar y llevar adelante la tarea de informar y difundir el impacto y alcance de las innovaciones tecnológicas en N&N. En este trabajo se comentan las acciones que se llevan a cabo en Argentina en el campo de la divulgación de N&N en distintos ámbitos educativos, difusión en medios de comunicación y eventos de participación masiva de la sociedad.New technologies involve a complex interplay of technical and social factors. The innovation that will produce nanotechnology and their benefits into society are only partially understood and constitute valuable issues to inform and discuss. The academic formation and scientific training of teachers and researchers from universities and scientific system is what allows to implement and carry out the task to inform and diffuse the impact and scope of technological innovations in N&N. This paper discusses the actions carried out in Argentina in the area of diffusion of N&N in different educational settings, broadcast media and events with massive participation of the society

Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study

α-Hemolysin (HlyA) is a protein toxin, a member of the pore-forming Repeat in Toxin (RTX) family, secreted by some pathogenic strands of Escherichia coli. The mechanism of action of this toxin seems to involve three stages that ultimately lead to cell lysis: binding, insertion, and oligomerization of the toxin within the membrane. Since the influence of phase segregation on HlyA binding and insertion in lipid membranes is not clearly understood, we explored at the meso- and nanoscale - both in situ and in real-time - the interaction of HlyA with lipid monolayers and bilayers. Our results demonstrate that HlyA could insert into monolayers of dioleoylphosphatidylcholine/sphingomyelin/cholesterol (DOPC/16:0SM/Cho) and DOPC/24:1SM/Cho. The time course for HlyA insertion was similar in both lipidic mixtures. HlyA insertion into DOPC/16:0SM/Cho monolayers, visualized by Brewster-angle microscopy (BAM), suggest an integration of the toxin into both the liquid-ordered and liquid-expanded phases. Atomic-force-microscopy imaging reported that phase boundaries favor the initial binding of the toxin, whereas after a longer time period the HlyA becomes localized into the liquid-disordered (Ld) phases of supported planar bilayers composed of DOPC/16:0SM/Cho. Our AFM images, however, showed that the HlyA interaction does not appear to match the general strategy described for other invasive proteins. We discuss these results in terms of the mechanism of action of HlyA.Instituto de Investigaciones Bioquímicas de La PlataInstituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

Decrease in the Roughness of Vapor-Deposited Gold Surfaces Induced by Surface Mobility

The evolution of the roughness exponent of vapor-deposited thin gold films (the object) on smooth glass substrate at 298 K has been observed by scanning tunneling microscopy. This evolution was enhanced by keeping the films at 323 K in contact with aqueous 0.5 M H2SO4 containing different KCl concentrations for 24 h. It implies a decay of the surface roughness for lengths larger than the grain size of the object leading to better ordered surface structures. Results are compared to those obtained during film grown by increasing the temperature of the glass substrate from 298 to 673 K. The analysis of surface roughness data indicated an enhancement of surface atom diffusion in ordering the gold surface structure, by either anion adsorption or deposition temperature.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Paraffin–Peloid Formulations from Copahue: Processing, Characterization and Application

The Copahue Thermal Center, situated in Neuquén, Argentina, produces natural and matured peloids, which are employed in the prevention and treatment of various osteoarticular and dermatological disorders. The presence of sulfur as a constituent and its thermotherapeutic potential constitute the primary strengths of these peloids. Nevertheless, accessing Copahue is challenging due to its distance from densely populated centers and the snow cover during the winter months in the southern hemisphere. Therefore, in order to propose a material that can be utilized year-round in any location, a mudpack was obtained by combining medicinal paraffin with dehydrated Copahue peloids, with concentrations evaluated up to 10% w/w. This mudpack was analyzed through X-ray diffraction, which detected the presence of sulfur, the most important component of Copahue’s peloids. Through IR spectroscopy, the signals that identify medicinal paraffin were clearly observed, and for concentrations of 6% and 10% peloid in the material, it was possible to detect the presence of mineral clay components associated with Si-O stretching vibrations at around 1041 cm−1. The low values of luminosity and grey tonality obtained for the mudpack contributed to patient acceptability and the absorption of electromagnetic radiation. The experimental cooling rate, calculated using the ratio of the temperature variation (∆T) with respect to the time variation (∆t) in each interval of the experimental curve, was determined to be 0.6 °C·min−1 for both paraffin and the mudpack. However, for peloids, higher values ranging from 0.6 to 4.8 °C·min−1 were obtained. This suggests that the mudpack mixtures have a slower heat release, which is a desirable property for their use as a thermotherapeutic agent. Considering the reusability of the mudpack, its stability was evaluated after 10 cycles of cooling and heating through XRD, DSC, and FTIR tests, resulting in a system that retains its properties. The formulation of the obtained mudpack is promising for the development of these materials on a larger scaleThis research was supported by the National University of Comahue, through project 04–I249: “Materiales adsorbentes naturales y modificados aplicados en termalismo

Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study

Abstractα-Hemolysin (HlyA) is a protein toxin, a member of the pore-forming Repeat in Toxin (RTX) family, secreted by some pathogenic strands of Escherichia coli. The mechanism of action of this toxin seems to involve three stages that ultimately lead to cell lysis: binding, insertion, and oligomerization of the toxin within the membrane. Since the influence of phase segregation on HlyA binding and insertion in lipid membranes is not clearly understood, we explored at the meso- and nanoscale—both in situ and in real-time—the interaction of HlyA with lipid monolayers and bilayers. Our results demonstrate that HlyA could insert into monolayers of dioleoylphosphatidylcholine/sphingomyelin/cholesterol (DOPC/16:0SM/Cho) and DOPC/24:1SM/Cho. The time course for HlyA insertion was similar in both lipidic mixtures. HlyA insertion into DOPC/16:0SM/Cho monolayers, visualized by Brewster-angle microscopy (BAM), suggest an integration of the toxin into both the liquid-ordered and liquid-expanded phases. Atomic-force-microscopy imaging reported that phase boundaries favor the initial binding of the toxin, whereas after a longer time period the HlyA becomes localized into the liquid-disordered (Ld) phases of supported planar bilayers composed of DOPC/16:0SM/Cho. Our AFM images, however, showed that the HlyA interaction does not appear to match the general strategy described for other invasive proteins. We discuss these results in terms of the mechanism of action of HlyA

Structural configurations of thin dried polyaniline films on gold(111) from scanning tunneling microscopy

The early stages of growth of polyaniline films electrodeposited on Au were studied by conventional electrochemical techniques, X-ray diffraction and ex situ scanning tunneling microscopy (STM). From high resolution STM imaging it appears that the first step of polyaniline formation involves the adsorption of aniline monomers on Au(111) terraces leading to domains with hexagonal arrays involving a phenyl-phenyl distance in the range 0.70 nm ⩽ d ⩽ 1.0 nm. The second step corresponds to the initiation of the polymer growth yielding typically 10 × 10 nm2 crystalline domains consisting of either 0.45 × 0.6 nm2 rectangular arrays or 0.75 × 0.45 nm2 arrays forming 120 ° angles. The crystalline domains coexist with highly disordered polymer domains. At advanced stages of growth, the formation of polymer fibers 2 nm in average width takes place leading to a full substrate coverage by a polymer deposit with an irregular surface.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Femtochemistry under scrutiny: Clocking state-resolved channels in the photodissociation of CH3I in the A -band

The following article appeared inThe Journal of Chemical Physics 152.1 (2020): 014304 and may be found at https://doi.org/10.1063/1.5134473Clocking of electronically and vibrationally state-resolved channels of the fast photodissociation of CH3I in the A-band is re-examined in a combined experimental and theoretical study. Experimentally, a femtosecond pump-probe scheme is employed in the modality of resonant probing by resonance enhanced multiphoton ionization (REMPI) of the methyl fragment in different vibrational states and detection through fragment velocity map ion (VMI) imaging as a function of the time delay. We revisit excitation to the center of the A-band at 268 nm and report new results for excitation to the blue of the band center at 243 nm. Theoretically, two approaches have been employed to shed light into the observations: first, a reduced dimensionality 4D nonadiabatic wavepacket calculation using the potential energy surfaces by Xie et al. [J. Phys. Chem. A 104, 1009 (2000)]; and second, a full dimension 9D trajectory surface-hopping calculation on the same potential energy surfaces, including the quantization of vibrational states of the methyl product. In addition, high level ab initio electronic structure calculations have been carried out to describe the CH3 3pz Rydberg state involved in the (2 + 1) REMPI probing process, as a function of the carbon-iodine (C–I) distance. A general qualitative agreement is obtained between experiment and theory, but the effect of methyl vibrational excitation in the umbrella mode on the clocking times is not well reproduced. The theoretical results reveal that no significant effect on the state-resolved appearance times is exerted by the nonadiabatic crossing through the conical intersection present in the first absorption band. The vibrationally state resolved clocking times observed experimentally can be rationalized when the (2 + 1) REMPI probing process is considered. None of the other probing methods applied thus far, i.e., multiphoton ionization photoelectron spectroscopy, soft X-ray innershell photoelectron spectroscopy, VUV single-photon ionization, and XUV core-to-valence transient absorption spectroscopy, have been able to provide quantum state-resolved (vibrational) clocking times. More experiments would be needed to disentangle the fine details in the clocking times and dissociation dynamics arising from the detection of specific quantum-states of the molecular fragmentsM.L.M.-S. acknowledges financial support through a predoctoral contract from Universidad Complutense de Madrid. M.E.C. is grateful to the Spanish MINECO for a contract through Programa de Técnicos de Apoyo a Infraestructuras. This work was financially supported by the Spanish MINECO and MICIU (Grant Nos. CTQ2016-75880-P, FIS2016-77889-R, and PGC2018-096444- B-I00). This research was carried out within the Unidad Asociada Química Física Molecular between the Departamento de Química Física of Universidad Complutense de Madrid and CSIC. The facilities provided by the Center for Ultrasfast Lasers of Universidad Complutense de Madrid are acknowledge

The JAK3Q988P mutation reveals oncogenic potential and resistance to ruxolitinib

T-cell acute lymphoblastic leukemia (T-ALL) arises from the malignant transformation of T-cell progenitors at various differentiation stages. Given that patients who relapse have a dismal prognosis, there is an urgent need to identify the molecular alterations that are present in such patients and promote leukemogenesis to implement personalized therapies with higher efficacy and fewer adverse effects. In the present manuscript, we identified the JAK3Q988P mutation in a T-ALL patient who did not achieve a durable response after the conventional treatment and whose tumor cells at relapse presented constitutive activation of the JAK/STAT pathway. Although JAK3Q988P has been previously identified in T-ALL patients from different studies, the functional consequences exerted by this mutation remain unexplored. Through the combination of different hematopoietic cellular models, we functionally characterize JAK3Q988P as an oncogenic mutation that contributes to leukemogenesis. Notably, JAK3Q988P not only promotes constitutive activation of the JAK/STAT pathway in the absence of cytokines and growth factors, as is the case for other JAK3 mutations that have been functionally characterized as oncogenic, but also functions independently of JAK1 and IL2RG, resulting in high oncogenic potential as well as resistance to ruxolitinib. Our results indicate that ruxolitinib may not be efficient for future patients bearing the JAK3Q988P mutation who instead may obtain greater benefits from treatments involving other pharmacological inhibitors such as tofacitinib.This work was supported in part by funds from Ministerio de Economía y Competitividad (SAF2015‐70561‐R; MINECO/FEDER, EU to J.F.‐P. and M.V.‐M.); Ministerio de Ciencia, Innovación y Universidades (RTI2018‐093330‐B‐I00; MCIU/FEDER, EU to J.F.‐P. and J.S.); Fundación Ramón Areces (CIVP19S7917 to J.F.‐P.); Comunidad de Madrid (B2017/BMD‐3778; LINFOMAS‐CM to J.F.‐P.); Asociación Española Contra el Cáncer (AECC, 2018; PROYE18054PIRI to J.F.‐P.);and Instituto de Investigación Sanitaria Fundación Jiménez Díaz to J.F.‐P.;institutional grants from the Fundación Ramón Areces and Banco de Santander to the CBMSO are also acknowledged.S

Self-assembled dithiothreitol on Au surfaces for biological applications: phospholipid bilayer formation

Self-assembly of dithiothreitol (DTT) on Au(111) from solution deposition has been studied by X-ray photoelectron spectroscopy and electrochemical data. DTT molecules self-assemble on Au(111) in a lying-down configuration irrespective of the concentration and temperature. XPS and electrochemical data indicate a DTT surface coverage of y E 0.16 with two S-head–Au covalent bonds per DTT molecule. The DTT monolayer turns the Au surface hydrophilic enough to allow the formation of fluid dimyristoylphosphatidylcholine (DMPC) bilayer domains by vesicle fusion as revealed by "in situ" atomic force imaging. Methylene blue (MB) and flavin adenine dinucleotide (FAD) have been used as probes to study molecule transport across the bilayer.Facultad de Ciencias ExactasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Morphological stabilization and KPZ scaling by electrochemically induced co-deposition of nanostructured NiW alloy films

We have assessed the stabilizing role that induced co-deposition has in the growth of nanostructured NiW alloy films by electrodeposition on polished steel substrates, under pulsed galvanostatic conditions. We have compared the kinetic roughening properties of NiW films with those of Ni films deposited under the same conditions, as assessed by Atomic Force Microscopy. The surface morphologies of both systems are super-rough at short times, but differ at long times: while a cauliflower-like structure dominates for Ni, the surfaces of NiW films display a nodular morphology consistent with more stable, conformal growth, whose height fluctuations are in the Kardar-Parisi- Zhang universality class of rough two-dimensional interfaces. These differences are explained by the mechanisms controlling surface growth in each case: mass transport through the electrolyte (Ni) and attachment of the incoming species to the growing interface (NiW). Thus, the long-time conformal growth regime is characteristic of electrochemical induced co-deposition under current conditions in which surface kinetics is hindered due to a complex reaction mechanism. These results agree with a theoretical model of surface growth in diffusion-limited systems, in which the key parameter is the relative importance of mass transport with respect to the kinetics of the attachment reaction.Facultad de Ciencias Exacta