Caceres, C., Moczko, E., Basozabal, I., Guerreiro, A., & Piletsky, S. (2021). Molecularly Imprinted Nanoparticles (NanoMIPs) Selective for Proteins: Optimization of a Protocol for Solid-Phase Synthesis Using Automatic Chemical Reactor. Polymers, 13(3), 314.
Abstract: Molecularly imprinted polymer nanoparticles (nanoMIPs) are receiving broad interest as robust and highly selective synthetic receptors for a variety of molecules. Due to their stability, inexpensive synthesis and easy implementation, they are considered a promising alternative to antibodies in sensors, diagnostics and separation applications. The most challenging targets for the production of synthetic receptors are proteins due to their fragile nature and the multitude of possible binding sites in their structure. Herein, we describe the modification and optimization of the protocol for synthesis of nanoMIPs with specificity for proteins using the prototype of an automated solid-phase synthesizer. Using an automated system gives an advantage for the simple, fast and fully controlled, reproducible production of nanoMIPs. The molecular imprinting in the reactor is performed using a template covalently immobilized on a solid support, in mild conditions suitable for preserving protein native structure. The validation of the protocol was made by assessing the ability to regenerate a solid-phase, and by measuring affinity and specificity of nanoparticles. As a model protein, we have chosen trypsin since its enzymatic activity can be easily monitored by using a commercial colorimetric assay. Different protocols were tested for their ability to improve the yield of high affinity nanoparticles in the final elution.
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Caceres, C., Moffat, R., & Pakalnis, R. (2017). Evaluation of flexural failure of sill mats using classical beam theory and numerical models. Int. J. Rock Mech. Min. Sci., 99, 21–27.
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Caceres, C., Morgado, M. D. G., Bozo, F. C., Piletsky, S., & Moczko, E. (2022). Rapid Selective Detection and Quantification of beta-Blockers Used in Doping Based on Molecularly Imprinted Nanoparticles (NanoMIPs). Polymers, 14(24), 5420.
Abstract: Human performance enhancing drugs (PEDs), frequently used in sport competitions, are strictly prohibited by the World Anti-Doping Agency (WADA). Biological samples collected from ath-letes and regular patients are continuously tested regarding the identification and/or quantification of the banned substances. Current work is focused on the application of a new analytical method, molecularly imprinted nanoparticles (nanoMIPs), to detect and determine concentrations of certain prohibited drugs, such as B-blockers, in water and human urine samples. These medications are used in the treatment of cardiovascular conditions, negative effects of adrenaline (helping to relief stress), and hypertension (slowing down the pulse and softening the arteries). They can also significantly increase muscle relaxation and improve heart efficiency. The new method of the detection and quantification of B-blockers is based on synthesis, characterization, and implementation of nanoMIPs (so-called plastic antibodies). It offers numerous advantages over the traditional methods, including high binding capacity, affinity, and selectivity for target molecules. Additionally, the whole process is less complicated, cheaper, and better controlled. The size and shape of the nanoMIPs is evaluated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The affinity and selectivity of the nanoparticles are investigated by competitive pseudo enzyme-linked immunosorbent assay (pseudo-ELISA) similar to common immunoassays employing natural antibodies. To provide reliable results towards either doping detection or therapeutic monitoring using the minimal invasive method, the qualitative and quantitative analysis of these drugs is performed in water and human urine samples. It is demonstrated that the assay can detect B-blockers in water within the linear range 1 nmolmiddotL(-1)-1 mmolmiddotL(-1) for atenolol with the detection limit 50.6 ng mL(-1), and the linear range 1 mmolmiddotL(-1)-10 mmolmiddotL(-1) for labetalol with the detection limit of 90.5 ngmiddotmL(-1). In human urine samples, the linear range is recorded in the concentration range 0.1 mmolmiddotL(-1)-10 nmolmiddotL(-1) for atenolol and 1 mmolmiddotL(-1)-10 nmolmiddotL(-1) for labetalol with a detection limit of 61.0 ngmiddotmL(-1)for atenolol and 99.4 ngmiddotmL(-1) for labetalol.
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Feinstein, A. D., Radica, M., Welbanks, L., Murray, C. A., Ohno, K., Coulombe, L. P., et al. (2023). Early Release Science of the exoplanet WASP-39b with JWST NIRISS. Nature, Early Access.
Abstract: The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy(1-4). However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality(5-9). Here we present the transmission spectrum of WASP-39b obtained using the Single-Object Slitless Spectroscopy (SOSS) mode of the Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST. This spectrum spans 0.6-2.8 mu m in wavelength and shows several water-absorption bands, the potassium resonance doublet and signatures of clouds. The precision and broad wavelength coverage of NIRISS/SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favouring a heavy-element enhancement ('metallicity') of about 10-30 times the solar value, a sub-solar carbon-to-oxygen (C/O) ratio and a solar-to-super-solar potassium-to-oxygen (K/O) ratio. The observations are also best explained by wavelength-dependent, non-grey clouds with inhomogeneous coverageof the planet's terminator.
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Lagos, F., Schreiber, M. R., Parsons, S. G., Zurlo, A., Mesa, D., Gansicke, B. T., et al. (2020). The White Dwarf Binary Pathways Survey -III. Contamination from hierarchical triples containing a white dwarf. Mon. Not. Roy. Astron. Soc., 494(1), 915–922.
Abstract: The White Dwarf Binary Pathways Survey aims at increasing the number of known detached A, F, G, and K main-sequence stars in close orbits with white dwarf companions (WD+AFGK binaries) to refine our understanding about compact binary evolution and the nature of Supernova Ia progenitors. These close WD+AFGK binary stars are expected to form through common envelope evolution, in which tidal forces tend to circularize the orbit. However, some of the identified WD+AFGK binary candidates show eccentric orbits, indicating that these systems are either formed through a different mechanism or perhaps they are not close WD+AFGK binaries. We observed one of these eccentric WD+AFGK binaries with SPHERE and find that the system TYC 7218-934-1 is in fact a triple system where the WD is a distant companion. The inner binary likely consists of the G-type star plus an unseen low-mass companion in an eccentric orbit. Based on this finding, we estimate the fraction of triple systems that could contaminate the WD+AFGK sample. We find that less than 15 per cent of our targets with orbital periods shorter than 100 d might be hierarchical triples.
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Lagos, M., Caceres, C. W., & Lardies, M. A. (2014). Geographic variation in acid- base balance of the intertidal crustacean Cyclograpsus cinereus ( Decapoda, Grapsidae) during air exposure. J. Mar. Biol. Assoc. U.K., 94(1), 159–165.
Abstract: In intertidal poikilotherms with wide geographic distribution, physiological variations are ubiquitous, due to phenotypic plasticity and/or individual geographic variation. Using the grapsid crab, Cyclograpsus cinereus as a study model, acclimatization differences in respiratory physiology were evaluated among populations along the Chilean coast, covering a latitudinal gradient of about 2000km. This species inhabits the supratidal zones and, therefore, is subject to constant immersion and emersion periods, producing physiological acidification due to CO2 retention, mainly in the branchial cavity. Individuals of six populations were collected along the coastline of Chile and were exposed to air for different time periods in the laboratory. The following parameters were measured: pH, Ca2+, Cl- and haemolymphatic lactate dehydrogenase (LDH) enzyme activity. Populations from lower latitudes were significantly different from those from central and southern Chile, with a higher haemolymphatic pH variation and higher Ca2+ level, along with lower levels of Cl- and LDH enzyme activity. This indicates that the populations from lower latitudes, which are subject to higher air temperatures during emersion, have a higher homeostatic capacity during emersion periods than those of intermediate and higher latitudes. This response seems to be determined by genetic bases due to adaptation to the local environment.
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Moffat, R., Caceres, C., & Tapia, E. (2021). Rock Pillar Design Using a Masonry Equivalent Numerical Model. Energies, 14(4), 890.
Abstract: In underground mining, the design of rock pillars is of crucial importance as these are structures that allow safe mining by maintaining the stability of the surrounding excavations. Pillar design is often a complex task, as it involves estimating the loads at depths and the strength of the rock mass fabric, which depend on the intact strength of the rock and the shape of the pillar in terms of the aspect ratio (width/height). The design also depends on the number, persistence, orientation, and strength of the discontinuities with respect to the orientation and magnitude of the stresses present. Solutions to this engineering problem are based on one or more of the following approaches: empirical design methods, practical experience, and/or numerical modeling. Based on the similarities between masonry structures and rock mass characteristics, an equivalent approach is proposed as the one commonly used in masonry but applied to rock pillar design. Numerical models using different geometric configurations and state of stresses are carried out using a finite difference numerical approach with an adapted masonry model applied to rocks. The results show the capability of the numerical approach to replicate common types of pillar failure modes and stability thresholds as those observed in practice.
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Sanhueza, L., Garrido, K., Celis, F., Garcia, M., Caceres, C., Moczko, E., et al. (2023). Tailoring the electroactive area of carbon screen-printed electrodes by simple activation steps towards rutin determination. J. Solid State Electrochem., 27, 1511–1521.
Abstract: Screen-printed electrodes (SPEs) have the advantage of being considered electrochemical cells that can be implemented in portable sensor applications. With the aim to improve the SPE performance, herein, we present different electrochemical surface modifications of carbon-based SPEs by cyclic voltammetry in hydrogen peroxide or sodium peroxide solution. SPEs were characterized using contact angle, Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS), and electrochemical methods, including cyclic voltammetry (CV), electrochemical impedance spectroscopy, and square wave voltammetry (SVW). Main results agree with the observed changes by Raman spectroscopy and the sp(2)/sp(3) ratio (I-D/I-G) of carbon vibrational bands. The diminishing of C-2 Swan signal determined by LIBS suggests that the activation steps produced defects onto the working electrode in the SPE. Considering that the different intermolecular forces of the redox couples are useful to indirectly evaluate the different functional groups, the activated SPEs were studied in the presence of rutin and [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) redox couples. Main results show that the electrochemical response of the activated electrode surfaces can be properly used to improve the rutin electrochemical determination.
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