The goal of this work is to demonstrate the positive effect of high energy ball milling on the magnetocaloric properties of materials based on strontium-calcium doped lanthanum manganite. We report a ...detailed study of crystal structure, magnetic behavior and magnetocaloric effect of La0.7Ca0.3−xSrxMnO3 (0 ≤ x ≤ 0.2, Δx = 0.05) powders, synthesized by assisted high-energy ball milling. The X-ray diffraction patterns disclose the complete formation of manganite with an orthorhombic structure for x ≤ 0.15, and rhombohedral structure for x = 0.2. Magnetic properties show a reduction of the magnetic saturation, and an increase in the Curie temperature with the strontium substitution, in all explored compositions (above room temperature). Arrot curves display that strontium doped manganites exhibit a second-order magnetic transition from ferrimagnetic to paramagnetic order. The magnetocaloric effect was calculated by measuring the isothermal magnetization around the Curie temperature, from 0 to 1.8 T, using Maxwell relations. All the synthesized manganites show magnetocaloric effect larger as compared to that of the parent compounds synthesized by other methods. The un-doped sample (x = 0) presents 7.43 J kg−1 K−1 and 93.29 J kg−1 of maximum magnetic entropy change (|ΔSM|) and the relative cooling power (RCP), respectively, under a low applied field (μoH) of 1.8 T. As it is expected, the introduction of strontium into the manganite, slightly reduces the magnetic entropy at 1.8 T, from 6.29 to 3.47 J kg−1 K−1 for x = 0.05 and x = 0.2, respectively. At the same time, the presence of strontium increases the working temperature above room temperature for strontium contents higer than 0.05, both attributed to the change in the crystal structure. These values are suitable for room-temperature magnetic refrigeration applications, using low magnetic fields (<1.8 T), increasing its potential application in the domestic refrigeration.
Screening for novel antibacterial compounds in small molecule libraries has a low success rate. We applied machine learning (ML)-based virtual screening for antibacterial activity and evaluated its ...predictive power by experimental validation. We first binarized 29,537 compounds according to their growth inhibitory activity (hit rate 0.87%) against the antibiotic-resistant bacterium Burkholderia cenocepacia and described their molecular features with a directed-message passing neural network (D-MPNN). Then, we used the data to train an ML model that achieved a receiver operating characteristic (ROC) score of 0.823 on the test set. Finally, we predicted antibacterial activity in virtual libraries corresponding to 1,614 compounds from the Food and Drug Administration (FDA)-approved list and 224,205 natural products. Hit rates of 26% and 12%, respectively, were obtained when we tested the top-ranked predicted compounds for growth inhibitory activity against B. cenocepacia, which represents at least a 14-fold increase from the previous hit rate. In addition, more than 51% of the predicted antibacterial natural compounds inhibited ESKAPE pathogens showing that predictions expand beyond the organism-specific dataset to a broad range of bacteria. Overall, the developed ML approach can be used for compound prioritization before screening, increasing the typical hit rate of drug discovery.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A Phase I interventional Clinical Trial was performed with a potential tuberculosis vaccine, based on detoxified cellular fragments of M. tuberculosis , named RUTI® . The objective was to ...evaluate the safety profile and T-cell immune responses over a 6-month period following subcutaneous inoculation. The double-blind, randomized and placebo-controlled trial was conducted in healthy volunteers, all recruited at one site. RUTI® , at each of the four tested doses, starting from 5 μg and going up to 200 μg, and placebo were inoculated to groups of 4 and 2 volunteers respectively, consecutively. RUTI® appeared to be well tolerated as judged by local and systemic clinical evaluation, though vaccine dose dependent local adverse reactions were recorded. T-cell responses of blood lymphocytes to PPD and a number of antigen subunits were elevated, when compared with controls subjects. These results support the feasibility of future evaluation, to be targeted at subjects with latent tuberculosis infection (LTBI).
The cell envelope of Gram-negative bacteria belonging to the Burkholderia cepacia complex (Bcc) presents unique restrictions to antibiotic penetration. As a consequence, Bcc species are notorious for ...causing recalcitrant multidrug-resistant infections in immunocompromised individuals. Here, we present the results of a genome-wide screen for cell envelope-associated resistance and susceptibility determinants in a Burkholderia cenocepacia clinical isolate. For this purpose, we construct a high-density, randomly-barcoded transposon mutant library and expose it to 19 cell envelope-targeting antibiotics. By quantifying relative mutant fitness with BarSeq, followed by validation with CRISPR-interference, we profile over a hundred functional associations and identify mediators of antibiotic susceptibility in the Bcc cell envelope. We reveal connections between β-lactam susceptibility, peptidoglycan synthesis, and blockages in undecaprenyl phosphate metabolism. The synergy of the β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is primarily mediated by inhibition of the PenB carbapenemase. In comparison with ceftazidime, avibactam more strongly potentiates the activity of aztreonam and meropenem in a panel of Bcc clinical isolates. Finally, we characterize in Bcc the iron and receptor-dependent activity of the siderophore-cephalosporin antibiotic, cefiderocol. Our work has implications for antibiotic target prioritization, and for using additional combinations of β-lactam/β-lactamase inhibitors that can extend the utility of current antibacterial therapies.
The objective of the present study was to evaluate the performance of a domestic wastewater treatment system based on hybrid constructed wetlands (CWs) under tropical climate. Moreover, the effect of ...different recirculation strategies particularly on nitrogen removal was also evaluated, including an analysis of nitrogen balance. The system was composed of a septic tank (pre-treatment), a horizontal subsurface flow and a vertical subsurface flow CWs. Three systems were analyzed: with the ornamental species Sagittaria lancifolia, the cattail Typha dominguensis and without vegetation as control. Evapotranspiration in the CWs was monitored during the warmest period of the year. First, the three systems were operated in serial mode evaluating two contact times of 2 d and 4 d. The three hybrid CWs were able to remove more than 92% of organic matter (COD, BOD5 and TOC), 88% of TSS and 99% (equivalent to 4.5 log10 units) of pathogens (Total Coliforms and Escherichia coli), regardless of plant selection and contact time. However, applying a contact time of 4 d resulted in higher removal of pathogens. Concerning nutrients removal, the combination of a contact time of 4 d and vegetation was required to achieve removal efficiencies over 66% for nitrogen and 90% for phosphorus. Finally, two recirculation strategies (RS) using a contact time of 4 d were evaluated in order to enhance nitrogen removal: RS1 (to the horizontal units) and RS2 (to the septic tank). The results yielded removal efficiencies similar to those obtained during serial operation in the case of organic matter (COD and BOD5) and phosphorus regardless of the RS applied. However, the removal of TSS decreased with RS2 as expected, due to the new load of solids coming from the septic tank. Nevertheless, nitrogen removal was increased over 85% in the hybrid CWs with vegetation, satisfactorily achieving system optimization. The highest nitrogen removal efficiency (≈ 97%) was obtained with the combination of RS2 and the plant species T. dominguensis. However, the use of the ornamental species S. lancifolia was not discarded since it provides an additional aesthetic benefit.
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•Hybrid CWs system for domestic wastewater under tropical climate was evaluated•High removal of organics and solids (>88%), regardless of vegetation and time•Higher removal of phosphorus (>90%) and pathogens (>log4.8) with 4 d and vegetation•Vegetation and 4 d for removal of nitrogen between 60 and 70% with serial operation•Recirculation helped enhance nitrogen removal over 85% (max. 97%)
This study contributes to the development of a soft computing tool used for the integration of hybrid renewable energy systems. The tool consists of the integration of a forecasting sub-tool for ...assessing quantitative and qualitative data. These data are input for a fuzzy multi-objective decision model developed in GAMS, where the total present value and the CO2 emissions of the system are minimized to obtain a set of Pareto alternatives. These alternatives are used as input for a fuzzy multi-attribute model developed in MATLAB. The CO2 emissions and the total present value, together with social, technologic, and environmental criteria are used as inputs for choosing the most sustainable alternative. Finally, the tool is tested in Puerto Guzmán, a small village of the department of Putumayo in southern Colombia. The selected and most sustainable alternative is composed of 31.2% diesel, 47.7% gasification of biomass, 7.9% solar photovoltaic and the rest with small hydro. The total present value of the system is 0.56 million USD and CO2 emissions are 0.4 million kg.
•A soft computing tool to integrate hybrid sustainable energy systems is proposed.•Fuzzy multi-criteria decision analysis models are the core of the soft computer tool.•Fuzzy multi-objective model considers uncertain and imprecise quantitative parameters.•Fuzzy multi-attribute model considers subjective and vague qualitative parameters.•Hybrid systems are efficiently assessed through a soft computer tool.
We propose using power-over-fiber (PoF) in some part of future 5G cellular solutions based on radio access networks considering currently installed front-haul solutions with single mode fiber to ...optically power communication systems for 5G new radio (NR) data transmission. Simulations addressing design parameters are presented. Radio-over-fiber (RoF) transmission over single mode fiber (SMF) is experimentally implemented and tested for link lengths ranging from 100 m up to 10 km with injected PoF signals up to 2 W. 64QAM, 16QAM and QPSK data traffic of 100 MHz bandwidth are transmitted simultaneously with the PoF signal showing an EVM compliant with 5G NR standard, and up to 0.5 W for 256QAM. EVM of 4.3% is achieved with RF signal of 20 GHz and QPSK modulation format in coexistence with delivering 870 mW of optical power to a photovoltaic cell (PV) after 10 km-long SMF link. Using PoF technology to optically powering remote units and Internet-of-Things (IoT) solutions based on RoF links is also discussed.
Several bacterial species from the Burkholderia cepacia complex (Bcc) are feared opportunistic pathogens that lead to debilitating lung infections with a high risk of developing fatal septicemia in ...cystic fibrosis (CF) patients. However, the pathogenic potential of other Bcc species is yet unknown. To elucidate clinical relevance of Burkholderia contaminans, a species frequently isolated from CF respiratory samples in Ibero-American countries, we aimed to identify its key virulence factors possibly linked with an unfavorable clinical outcome. We performed a genome-wide comparative analysis of two isolates of B. contaminans ST872 from sputum and blood culture of a female CF patient in Argentina. RNA-seq data showed significant changes in expression for quorum sensing-regulated virulence factors and motility and chemotaxis. Furthermore, we detected expression changes in a recently described low-oxygen-activated (lxa) locus which encodes stress-related proteins, and for two clusters responsible for the biosynthesis of antifungal and hemolytic compounds pyrrolnitrin and occidiofungin. Based on phenotypic assays that confirmed changes in motility and in proteolytic, hemolytic and antifungal activities, we were able to distinguish two phenotypes of B. contaminans that coexisted in the host and entered her bloodstream. Whole genome sequencing revealed that the sputum and bloodstream isolates (each representing a distinct phenotype) differed by over 1,400 mutations as a result of a mismatch repair-deficient hypermutable state of the sputum isolate. The inferred lack of purifying selection against nonsynonymous mutations and the high rate of pseudogenization in the derived isolate indicated limited evolutionary pressure during evolution in the nutrient-rich, stable CF sputum environment. The present study is the first to examine the genomic and transcriptomic differences between longitudinal isolates of B. contaminans. Detected activity of a number of putative virulence factors implies a genuine pathogenic nature of this novel Bcc species.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
One of the main challenges in the food industry is to design strategies for the successful incorporation of natural sources of bioactive compounds. Recently, yogurts and other fermented dairy ...beverages have been proposed as ideal carriers of such bioactive compounds such as fatty acids and antioxidants that could improve consumers' health. However, the incorporation of new ingredients causes functional and structural modifications that may affect the consumers' preferences. In this work, a dairy beverage model supplemented with oleic acid has been designed by partial substitution of milk by Candida utilis single-cell protein extract. The changes in the structural properties of this new beverage were evaluated by following the fermentation process, pH, aggregate size, microstructure, and changes in rheological properties. Furthermore, molecular dynamics simulations were carried out to analyze the interaction between its main components. Our data revealed that samples with a percentage of milk substitution of 30% showed a higher viscosity as compared with the other percentages and less viscosity than the control (no substitution). These samples were then selected for fortification by incorporating oleic acid microcapsules. A concentration of 1.5 g/100 g was shown to be the optimal quantity of microcapsules for oleic acid supplementation. Molecular dynamic simulations revealed glutathione as an important component of the micro-gel structure. The present study forms the basis for novel studies where Candida utilis single-cell protein and microencapsulated essential oils could be used to design innovative bioproducts.
The aim of this study was to assess the accuracy of a Principal Components Analysis (PCA)-based method for reflectance reconstruction and color estimation of layered dental resin-based composites ...with different thicknesses.
Bi-layered samples of different clinically relevant thicknesses were created using shades of VITAPAN Excell (VE), VITAPAN Dentine (VD) and VITA Physiodens (VP), combined with their corresponding enamel shades. Spectral reflectance of all samples was measured over a black background using a non-contact spectroradiometer with CIE 45∘∕0∘ geometry. Two different PCA-based models, built from two different configurations of known samples, were proposed to reconstruct the spectral data and color of unknown layered samples. Root Mean Square Error (RMSE), Goodness of Fit (GFC), as well as ΔE00 with corresponding 50:50% acceptability and perceptibly thresholds (AT and PT) were used as performance assessment.
The 5-samples training set approach provided an average RMSE < 0.015 and GFC > 0.999 when measured and predicted spectral reflectances were compared, while for the 9-samples training set, RMSE < 0.0098 and GFC > 0.9999 were obtained. The overall mean color differences obtained with the 5-samples training set approach were ΔE00 = 0.99 (AT% = 96.25% and PT% = 32.50%), while using the 9-samples training set resulted in lower overall mean color differences: ΔE00 = 0.50 (AT% = 99.22% and PT% = 83.87%).
Within the framework of this study, the two proposed PCA-based configurations allow the prediction of the spectral reflectance of layered dental resin-based composites of different shades and thicknesses, with a high degree of accuracy.
•Reflectance data of layered dental materials can be estimated by PCA-based algorithms.•Training set size affects the accuracy of reflectance and color estimations.•Shade variations do not affect the accuracy of the estimation.•The accuracy of the estimation depends on type of dental resin composite.•Predicted vs. measured color differences are generally within acceptable limits.
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