2,259 research outputs found
Gold(I) complexes bearing alkylated 1, 3, 5-triaza-7-phosphaadamantane ligands as thermoresponsive anticancer agents in human colon cells
Overheating can affect solubility or lipophilicity, among other properties, of some an-ticancer drugs. These temperature-dependent changes can improve efficiency and selectivity of the drugs, since they may affect their bioavailability, diffusion through cell membrane or activity. One recent approach to create thermosensitive molecules is the incorporation of fluorine atoms in the chemical structure, since fluor can tune some chemical properties such as binding affinity. Herein we report the anticancer effect of gold derivatives with phosphanes derived from 1, 3, 5-triaza-7-phosphaadamantane (PTA) with long hydrocarbon chains and the homologous fluorinated chains. Besides, we analysed the influence of temperature in the cytotoxic effect. The studied gold(I) complexes with phosphanes derived from PTA showed antiproliferative effect on human colon carcinoma cells (Caco-2/TC7 cell line), probably by inhibiting cellular TrxR causing a dysfunction in the intracellular redox state. In addition, the cell cycle was altered by the activation of p53, and the complexes produce apoptosis through mitochondrial depolarization and the consequent activation of caspase-3. Furthermore, the results suggest that this cytotoxic effect is enhanced by hyperthermia and the presence of polyfluorinated chains. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Effect of modified atmosphere packaging (MAP) and UC-C irradiation on postharvest quality of red raspberries
Red raspberries (Rubus idaeus L.) are highly appreciated by consumers. However, their postharvest shelf life scarcely exceeds 5 d under the refrigeration temperatures usually applied during commercialization, due to their high susceptibility to dehydration, softening and rot incidence. Thus, the objective of this study was to investigate the ability of UV-C radiation (UV1: 2 kJ m-2 and UV2: 4 kJ m-2 ), passive modified atmosphere packaging (MAP) with transmission rates (TR) for O2 and CO2 of 1805 mL d-1 and 1570 mL d-1 (MAP1), and 902 mL d-1 and 785 mL d-1 (MAP2), respectively, and the combination of both technologies to prolong raspberries’ shelf life at 6¿ C. Their influence on respiration, physicochemical parameters, and microbiological and nutritional quality was assessed during 12 d of storage. The combination of 4 kJ m-2 UV-C radiation and a packaging film with O2 and CO2 transmission rates of 902 mL d-1 and 785 mL d-1, respectively, produced a synergistic effect against rot development, delaying senescence of the fruit. The UV2MAP2 and MAP2 samples only showed 1.66% rot incidence after 8 d of storage. The UV2MAP2 samples also had higher bioactive content (1.76 g kg-1 of gallic acid equivalents (GAE), 1.08 g kg-1 of catechin equivalents (CE) and 0.32 g kg-1 of cyanidin 3-O-glucoside equivalents (CGE)) than the control samples at the end of their shelf life. Moreover, the mass loss was minimal (0.56%), and fruit color and firmness were maintained during shelf life. However, the rest of the batches were not suitable for commercialization after 4 d due to excessive mold development. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
CMOS Duobinary Transceiver for Multigigabit Communications
This work presents a CMOS transceiver for amplitude duobinary modulation over an equalized 50-m step-index plastic optical fiber (SI-POF). Both duobinary precoder and decoder have been fabricated in 0.18-μm CMOS technology, enabling a bandlimited system of 700 MHz to operate at 3.125 Gbps with a consumption of 28.4 mW
Effect of nucleon exchange on projectile multifragmentation in the reactions of 28Si + 112Sn and 124Sn at 30 and 50 MeV/nucleon
Multifragmentation of quasiprojectiles was studied in reactions of 28Si beam
with 112Sn and 124Sn targets at projectile energies 30 and 50 MeV/nucleon. The
quasiprojectile observables were reconstructed using isotopically identified
charged particles with Z_f <= 5 detected at forward angles. The nucleon
exchange between projectile and target was investigated using isospin and
excitation energy of reconstructed quasiprojectile. For events with total
reconstructed charge equal to the charge of the beam (Z_tot = 14) the influence
of beam energy and target isospin on neutron transfer was studied in detail.
Simulations employing subsequently model of deep inelastic transfer,
statistical model of multifragmentation and software replica of FAUST detector
array were carried out. A concept of deep inelastic transfer provides good
description of production of highly excited quasiprojectiles. The isospin and
excitation energy of quasiprojectile were described with good overall
agreement. The fragment multiplicity, charge and isospin were reproduced
satisfactorily. The range of contributing impact parameters was determined
using backtracing procedure.Comment: 11 pages, 8 Postscript figures, LaTeX, to appear in Phys. Rev. C (
Dec 2000
Tratamiento de la columna vertebral en la educación secundaria obligatoria: parte I - prevención y ejercicios poco recomendables
El dolor de espalda es uno de los motivos más frecuentes por los cuales se acude a la consulta médica y es preocupante la cada vez más temprana edad en la cual se presentan estos problemas. Ello impone la necesidad de dar a conocer a los alumnos de Educación Secundaria Obligatoria unos mínimos conocimientos acerca de la anatomía de la columna vertebral y ciertos recursos ergonómicos para adoptar actitudes posturales correctas. Por otro lado, el profesor de Educación Física ha de conocer cuáles son los ejercicios, de forma general, menos recomendables en la prevención de determinados problemas de espalda
Tratamiento de la columna vertebral en la educación secundaria obligatoria: parte II - ejercicios recomendables
El dolor de espalda en personas adultas es producido, en numerosas ocasiones, por una inadecuada educación postural y una deficiente condición física. Esta situación provoca un desequilibrio muscular en aquellos grupos musculares responsables de mantener la postura. En la E.S.O, también se producen tales desequilibrios por lo que, como actitud preventiva y educadora, es recomendable tener en cuenta el tratamiento corporal que sufren los alumnos a lo largo del día y durante las clases de Educación Física. Entre los ejercicios que favorecen la reeducación postural así como su desarrollo y mantenimiento, se ha realizado una selección de los que se consideran no debería faltar en una programación de E.F para la ESO
Inhomogeneous isospin distribution in the reactions of 28Si + 112Sn and 124Sn at 30 and 50 MeV/nucleon
We have created quasiprojectiles of varying isospin via peripheral reactions
of 28Si + 112Sn and 124Sn at 30 and 50 MeV/nucleon. The quasiprojectiles have
been reconstructed from completely isotopically identified fragments. The
difference in N/Z of the reconstructed quasiprojectiles allows the
investigation of the disassembly as a function of the isospin of the
fragmenting system. The isobaric yield ratio 3H/3He depends strongly on N/Z
ratio of quasiprojectiles. The dependences of mean fragment multiplicity and
mean N/Z ratio of the fragments on N/Z ratio of the quasiprojectile are
different for light charged particles and intermediate mass fragments.
Observation of a different N/Z ratio of light charged particles and
intermediate mass fragments is consistent with an inhomogeneous distribution of
isospin in the fragmenting system.Comment: 5 pages, 4 Postscript figures, RevTe
Limits on Quaoar's Atmosphere
Here we present high cadence photometry taken by the Acquisition Camera on Gemini South, of a close passage by the ~540 km radius Kuiper belt object, (50000) Quaoar, of a r' = 20.2 background star. Observations before and after the event show that the apparent impact parameter of the event was 0."019 ± 0."004, corresponding to a close approach of 580 ± 120 km to the center of Quaoar. No signatures of occultation by either Quaoar's limb or its potential atmosphere are detectable in the relative photometry of Quaoar and the target star, which were unresolved during closest approach. From this photometry we are able to put constraints on any potential atmosphere Quaoar might have. Using a Markov chain Monte Carlo and likelihood approach, we place pressure upper limits on sublimation supported, isothermal atmospheres of pure N_2, CO, and CH_4. For N_2 and CO, the upper limit surface pressures are 1 and 0.7 μbar, respectively. The surface temperature required for such low sublimation pressures is ~33 K, much lower than Quaoar's mean temperature of ~44 K measured by others. We conclude that Quaoar cannot have an isothermal N_2 or CO atmosphere. We cannot eliminate the possibility of a CH_4 atmosphere, but place upper surface pressure and mean temperature limits of ~138 nbar and ~44 K, respectively
Morphology and histology of the uropygial gland in Antarctic birds: relationship with their contact with the aquatic environment?
Fil: Chiale, María Cecilia. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Fernández, Patricia E.. Cátedra de Patología Genera. Facultad de Ciencias Veterinarias. Universidad Nacional de La Plata; ArgentinaFil: Gimeno, Eduardo J.. Cátedra de Patología General. Facultad de Ciencias Veterinarias. Universidad Nacional de La Plata; ArgentinaFil: Barbeito, Claudio G.. Cátedra de Histología y Embriología. Facultad de Ciencias Veterinarias. Universidad Nacional de La Plata; ArgentinaFil: Montalti, Diego. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin
Differences in temperature sensitivity and drought recovery between natural stands and plantations of conifers are species-specific
Forests are being impacted by climate and land-use changes which have altered their productivity and growth. Understanding how tree growth responds to climate in natural and planted stands may provide valuable information to prepare management in sight of climate change. Plantations are expected to show higher sensitivity to climate and lower post-drought resilience than natural stands, due to their lower compositional and structural diversity. We reconstructed and compared the radial growth of six conifers with contrasting ecological and climatic niches (Abies pinsapo, Cedrus atlantica, Pinus sylvestris, Pinus nigra, Pinus pinea, Pinus pinaster) in natural and planted stands subjected to seasonal drought in 40 sites. We quantified the relationships between individual growth variability and climate variables (temperature, precipitation and the SPEI drought index), as well as post-drought resilience. Elevated precipitation during the previous autumn-winter and current spring to early summer enhanced growth in both natural and planted stands of all species. Temperature effects on growth were less consistent: only plantations of A. pinsapo, C. atlantica, P. nigra, P. pinea, P. sylvetris and a natural stand of P. nigra showed negative impacts of summer temperature on growth. Drought reduced growth of all species in both plantations and natural stands, with variations in the temporal scale of the response. Drought constrained growth more severely in natural stands than in plantations of C. atlantica, P. pinaster and P. nigra, whereas the inverse pattern was found for A. pinsapo. Resilience to drought varied between species: natural stands of A. pinsapo, C. atlantica and P. pinaster recovered faster than plantations, while P. pinea plantations recovered faster than natural stands. Overall, plantations did not consistently show a higher sensitivity to climate and a lower capacity to recover after drought. Therefore, plantations are potential tools for mitigating climate warming. © 2021 The AuthorsThis study was supported by project FORMAL ( RTI2018-096884-B-C31 ) from the Spanish Ministry of Science, Innovation and Universities . GS-B was supported by a Spanish Ministry of Economy, Industry and Competitiveness Postdoctoral grant ( IJC2019-040571-I ; FEDER funds)
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