This work presents potential applications of low-cost fused deposition modeling 3D-printers to fabricate multiuse 3D-printed electrochemical cells for flow or batch measurements as well as the ...3D-printing of electrochemical sensing platforms. Electrochemical cells and sensors were printed with acrylonitrile butadiene styrene (ABS) and conductive graphene-doped polylactic acid (G-PLA) filaments, respectively. The overall printing operation time and estimated cost per cell were 6 h and $ 6.00, respectively, while the sensors were printed within minutes (16 sensor strips of 1 × 2 cm in 10 min at a cost of $ 1.00 each sensor). The cell performance is demonstrated for the amperometric detection of tert-butylhydroquinone, dipyrone, dopamine and diclofenac by flow-injection analysis (FIA) and batch-injection analysis (BIA) using different working electrodes, including the proposed 3D-printed sensor, which presented comparable electroanalytical performance with other carbon-based electrodes (LOD of 0.1 μmol L−1 for dopamine). Raman spectroscopy and scanning electron microscopy of the 3D-printed sensor indicated the presence of graphene nanoribbons within the polymeric matrix. Electrochemical impedance spectroscopy and heterogeneous electron transfer constants (k0) for the redox probe Ru(NH3)6+3 revealed that a glassy-carbon electrode presented faster electron transfer rates than the 3D-printed sensor; however, the latter presented lower LOD values for dopamine and catechol probably due to oxygenated functional groups at the G-PLA surface.
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•Low-cost fused deposition modeling (FDM) 3D-printers to produce cells and electrodes.•Multiuse cells for flow- (FIA) and batch-injection analysis (BIA) as well for batch condition.•Designs and printing conditions accessible for any FDM 3D-printers.•Graphene-doped PLA printed sensors for voltammetric and amperometric detection.•Electroanalytical performance similar to GCE modified with carbon nanomaterials.
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•Low-cost fused deposition modeling 3D-printed device for sampling and detection of TNT.•Graphene-doped polylacic acid (G-PLA) filament to fabricate the 3D-printed device.•Nanograms ...of TNT sampled from metallic, granite and glove surfaces were quantified.•Mechanical polishing of the 3D-printed surface improved the electrochemical properties.•Metal determination on the device was also shown; promising for gunshot residue analysis.
Fused deposition modelling 3D printing of a flexible, conductive, disposable and biodegradable platform using graphene-doped polylactic acid (G-PLA) was demonstrated as an integrated device for sampling and detection of explosives. As a proof-of-concept, traces of 2,4,6-Trinitrotoluene (TNT) impregnated on different surfaces were abrasively sampled using the 3D-printed device and readily assembled in a portable electrochemical cell for rapid square-wave voltammetry scans in the presence of 0.1 mol L–1 HCl electrolyte. Nanogram amounts of TNT sampled from metallic, granite and glove surfaces were detected and quantified using the Faraday equation applied to the voltammetric response of TNT immobilised on the electrode surface. Identification of TNT was possible due to the unique voltammetric behaviour obtained on the G-PLA sensor and efficient sampling due to the rough surface and flexibility of the device. Lead and copper determination by stripping voltammetry was also demonstrated on the same device, highlighting the possibility of detecting gunshot residues. Moreover, we demonstrated that simple mechanical polishing of the 3D-printed surface improved the electrochemical sensing properties of the sensor by exposing graphene nanoribbons within the PLA matrix. Hence, this 3D-printed integrated platform holds promise as a rapid and low-cost approach for on-site crime scene investigations.
► Highly rapid, selective and sensitive amperometric detection of H2O2 in milk. ► Prussian-blue modified electrode with improved stability and precision. ► Association with batch-injection analysis ...provided high analytical frequency. ► Satisfactory recovery values for milk analysis.
We report a highly rapid, precise, selective and sensitive analytical method for the determination of hydrogen peroxide in milk using a batch-injection analysis (BIA) with amperometric detection at a Prussian-blue bulk modified graphite-composite electrode. An electronic micropipette injected 100μL aliquots of 10-fold diluted samples (high and low-fat milk) directly onto the modified electrode immersed in the BIA cell. The analytical features of our proposed method includes low RSD between injections (0.76%, n=9), low detection limit (10μmolL−1), elevated analytical frequency (up to 80h−1) and satisfactory recovery values for spiked samples. A fresh and highly reproductive electrode surface can be easily obtained by simple mechanical polishing (RSD=1.6%, n=5). The storage stability of the PB-modified graphite-composite surpassed 1year keeping equivalent performance as initially presented. The association of BIA with an improved amperometric detector provides great promise for routine monitoring of hydrogen peroxide in milk and other beverages.
Seven new abietane diterpenoids, comprising medusanthol A–G (1–3, 5, 7–9) and two previously identified analogs (4 and 6), were isolated from the hexane extract of the aerial parts of Medusantha ...martiusii. The structures of the compounds were elucidated by HRESIMS, 1D/2D NMR spectroscopic data, IR spectroscopy, NMR calculations with DP4+ probability analysis, and ECD calculations. The anti-neuroinflammatory potential of compounds 1–7 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) and the proinflammatory cytokine TNF-α in BV2 microglia stimulated with LPS and IFN-γ. Compounds 1–4 and 7 exhibited decreased NO levels at a concentration of 12.5 µM. Compound 1 demonstrated strong activity with an IC50 of 3.12 µM, and compound 2 had an IC50 of 15.53 µM; both compounds effectively reduced NO levels compared to the positive control quercetin (IC50 11.8 µM). Additionally, both compounds significantly decreased TNF-α levels, indicating their potential as promising anti-neuroinflammatory agents.
The fabrication of carbon black/polylactic acid (PLA) electrodes using a 3D printing pen is presented and compared with electrodes obtained by a desktop fused deposition modelling (FDM) 3D printer. ...The 3D pen was used for the fast production of electrodes in two designs using customized 3D printed parts to act as template and guide the reproducible application of the 3D pen: (i) a single working electrode at the bottom of a 3D-printed cylindrical body and (ii) a three-electrode system on a 3D-printed planar substrate. Both devices were electrochemically characterized using the redox probe Fe(CN)63−/4- via cyclic voltammetry, which presented similar performance to an FDM 3D-printed electrode or a commercial screen-printed carbon electrode (SPE) regarding peak-to-peak separation (ΔEp) and current density. The surface treatment of the carbon black/PLA electrodes fabricated by both 3D pen and FDM 3D-printing procedures provided substantial improvement of the electrochemical activity by removing excess of PLA, which was confirmed by scanning electron microscopic images for electrodes fabricated by both procedures. Structural defects were not inserted after the electrochemical treatment as shown by Raman spectra (iD/iG), which indicates that the use of 3D pen can replace desktop 3D printers for electrode fabrication. Inter-electrode precision for the best device fabricated using the 3D pen (three-electrode system) was 4% (n = 5) considering current density and anodic peak potential for the redox probe. This device was applied for the detection of 2,4,6-trinitrotoluene (TNT) via square-wave voltammetry of a single-drop of 100 μL placed upon the thee-electrode system, resulting in three reduction peaks commonly verified for TNT on carbon electrodes. Limit of detection of 1.5 μmol L−1, linear range from 5 to 500 μmol L−1 and RSD lower than 4% for 10 repetitive measurements of 100 μmol L−1 TNT were obtained. The proposed devices can be reused after polishing on sandpaper generating new electrode surfaces, which is an extra advantage over chemically-modified electrochemical sensors applied for TNT detection.
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•3D pen fabricated carbon black/polylactic acid electrodes compared with 3D-printed electrodes.•Morphological analysis shows no difference, except to electrochemical surface treatment.•Highly reproducible planar three-electrode devices were fabricated (RSD = 4%, n = 5).•Similar results to those obtained on 3D-printed or screen-printed electrodes.•Application to TNT detection in a single drop (100 μL placed upon the device).
Foodborne diseases can be highlighted as one of the most significant health concerns among the last decades. Probiotic food products can be considered as the promising approaches for modulating of ...gastrointestinal (GIT) microbiota due to their interactions within the GIT. However, no comprehensive review regarding the involved mechanisms in inhibiting foodborne pathogens in foods by probiotics, besides their interaction is available.
The current article provides an overview considering the interactions between probiotics and pathogens in hosts as well as in foods aiming to gain insights regarding relevant properties to be used in further developments of probiotic-based food products.
The interaction between probiotics and pathogens in foods and in the hosts and different mechanism of probiotics in control of enteric pathogens colonization were reviewed in the current study. While the mechanisms of action correlated with probiotic strains in the GIT are diverse and well-studied, their interactions with pathogens in foods is overlooked. Revealing how probiotic strains interact with foodborne pathogens in foods is of key relevance in a contemporary context that demand the development of more robust formulations. Although several mechanisms such as production of substances such as organic acids, bacteriocins, and hydrogen peroxide have been suggested regarding probiotics actions in food matrices, still substantial challenges exist concerning the molecular mode of their antimicrobial action. Additionally, it is required to comprehend the appreciate dose, species, and a combination of probiotics in controlling the pathogens.
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•Probiotics are microorganisms with great health benefits and protect host against foodborne illness.•The demand for food products containing probiotic is continuously increasing.•The effectiveness is associated with the interaction with pathogens, host's immune system and GUT.•Delivery systems can protect probiotics from environmental stress and enhance their efficiency.
Interleukin 32 (IL‐32) is a proinflammatory cytokine, expressed as 9 distinct isoforms. The most active isoform is the predominantly intracellular‐functioning IL‐32γ. Involvement of IL‐32 in ...infectious diseases is increasingly being appreciated. Production of IL‐32 promotes pathways that serve to control bacterial infection, especially those caused by mycobacteria. A similar role for this cytokine is observed in the cellular response to viral infections. In addition to its protective effects against microorganisms, IL‐32 is involved in immunopathogenesis of some infectious diseases. In parasitic diseases, it has been demonstrated that this cytokine is induced by Leishmania infection. In this review, we summarize the present data on the role of IL‐32 in infectious diseases, highlighting this cytokine as new target for control of infections.
Review on the properties of IL‐32 and its immune modulation role in bacterial, viral, and other infectious diseases.
In this work, we report a simple and novel strategy for simultaneous analysis using flow injection analysis with multiple pulse amperometric (FIA‐MPA) detection. The proposed strategy was ...successfully used for simultaneous determination of paracetamol and caffeine (model analytes) in pharmaceutical formulations. A sequence of potential pulses (waveform) was selected in such a way that PA is selectively oxidized at E1 (+1.20 V/50 ms) and both compounds (PA+CA) are simultaneously oxidized at E2 (+1.55 V/50 ms); hence, current subtraction (using a correction factor) can be used for the selective determination of CA. The proposed FIA method is simple, cheap, fast (140 injections h−1), and present selectivity for the determination of both compounds in pharmaceutical samples, with results similar to those obtained by HPLC at a 95 % confidence level.
The demand for processing ever increasing amounts of genomic data has raised new challenges for the implementation of highly scalable and efficient computational systems. In this paper we propose ...SparkBLAST, a parallelization of a sequence alignment application (BLAST) that employs cloud computing for the provisioning of computational resources and Apache Spark as the coordination framework. As a proof of concept, some radionuclide-resistant bacterial genomes were selected for similarity analysis.
Experiments in Google and Microsoft Azure clouds demonstrated that SparkBLAST outperforms an equivalent system implemented on Hadoop in terms of speedup and execution times.
The superior performance of SparkBLAST is mainly due to the in-memory operations available through the Spark framework, consequently reducing the number of local I/O operations required for distributed BLAST processing.
It is unknown whether angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) have a positive, neutral, or negative effect on clinical outcomes in patients with ...coronavirus disease 2019 (COVID-19).
To determine whether discontinuation compared with continuation of ACEIs or ARBs changed the number of days alive and out of the hospital through 30 days.
A randomized clinical trial of 659 patients hospitalized in Brazil with mild to moderate COVID-19 who were taking ACEIs or ARBs prior to hospitalization (enrolled: April 9-June 26, 2020; final follow-up: July 26, 2020).
Discontinuation (n = 334) or continuation (n = 325) of ACEIs or ARBs.
The primary outcome was the number of days alive and out of the hospital through 30 days. Secondary outcomes included death, cardiovascular death, and COVID-19 progression.
Among 659 patients, the median age was 55.1 years (interquartile range IQR, 46.1-65.0 years), 14.7% were aged 70 years or older, 40.4% were women, and 100% completed the trial. The median time from symptom onset to hospital admission was 6 days (IQR, 4-9 days) and 27.2% of patients had an oxygen saturation of less than 94% of room air at baseline. In terms of clinical severity, 57.1% of patients were considered mild at hospital admission and 42.9% were considered moderate. There was no significant difference in the number of days alive and out of the hospital in patients in the discontinuation group (mean, 21.9 days SD, 8 days) vs patients in the continuation group (mean, 22.9 days SD, 7.1 days) and the mean ratio was 0.95 (95% CI, 0.90-1.01). There also was no statistically significant difference in death (2.7% for the discontinuation group vs 2.8% for the continuation group; odds ratio OR, 0.97 95% CI, 0.38-2.52), cardiovascular death (0.6% vs 0.3%, respectively; OR, 1.95 95% CI, 0.19-42.12), or COVID-19 progression (38.3% vs 32.3%; OR, 1.30 95% CI, 0.95-1.80). The most common adverse events were respiratory failure requiring invasive mechanical ventilation (9.6% in the discontinuation group vs 7.7% in the continuation group), shock requiring vasopressors (8.4% vs 7.1%, respectively), acute myocardial infarction (7.5% vs 4.6%), new or worsening heart failure (4.2% vs 4.9%), and acute kidney failure requiring hemodialysis (3.3% vs 2.8%).
Among patients hospitalized with mild to moderate COVID-19 and who were taking ACEIs or ARBs before hospital admission, there was no significant difference in the mean number of days alive and out of the hospital for those assigned to discontinue vs continue these medications. These findings do not support routinely discontinuing ACEIs or ARBs among patients hospitalized with mild to moderate COVID-19 if there is an indication for treatment.
ClinicalTrials.gov Identifier: NCT04364893.
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