Multisensor Magnetic Scanning Microscope for Remanent Magnetic Field Measurements.

Magnetic Scanning Microscopy (MSM) emerged with the aim of allowing the visualization of magnetic fields of a sample or material through scanning and proved particularly useful for geology, biomedicine, characterization of magnetic materials, and in the steel industry. In this regard, the reading system of an MSM was modified using a µ-metal magnetic shielding structure to analyze remanent fields. The MSM was adapted to perform readings using two different types of sensors. The sensitive area of the sensors was evaluated, and the HQ-0811 (AKM-Asahi KaseiTM Microdevices) and STJ-010 (Micro MagneticsTM) sensors were chosen, with the HQ-0811 standardized on Printed Circuit Boards (PCBs) to facilitate handling and increase the system's robustness. In the shielded chamber, two piezoelectric ANC-150 stepper motors (Attocube Systems) were used, arranged planarly, to allow the movement of the analyzed samples under the mounted sensors. To acquire data from the sensors, the Precision Current Source Model 6220 and the Nanovoltmeter Model 2182A (both from Keithley) were used, along with Keithley's Delta-Mode integrated system. To analyze the system's effectiveness, three distinct samples were analyzed for calibration, and a MATLAB program was written to analyze the images and extract the material's magnetization. Additionally, a rock sample from the Parnaíba Basin was mapped to demonstrate the system's capabilities.

Enhancement of biogas production rate from bioplastics by alkaline pretreatment.

The effect of alkali-based pretreatment on the methanization of bioplastics was investigated. The tested bioplastics included PHB [poly(3-hydroxybutyrate)], PHBH [poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)], PHBV [poly(3-hydroxybutyrate-co-3-hydroxyvalerate], PLA (polylactic acid), and a PLA/PCL [poly(caprolactone)] 80/20 blend. Prior to methanization tests, the powdered polymers (500-1000 µm) at a concentration of 50 g/L were subjected to alkaline pretreatment using NaOH 1 M for PLA and PLA/PCL, and NaOH 2 M for PHB-based materials. Following 7 days of pretreatment, the amount of solubilized carbon for PLA and its blend accounted for 92-98% of the total initial carbon, while lower carbon recoveries were recorded for most PHB-based materials (80-93%), as revealed by dissolved total organic carbon analysis. The pretreated bioplastics were then tested for biogas production by means of mesophilic biochemical methane potential tests. Compared to unpretreated PHBs, methanization rates of pretreated PHBs were accelerated by a factor of 2.7 to 9.1 with comparable (430 NmL CH4/g material feed) or slightly lower (15% in the case of PHBH) methane yields, despite featuring a 1.4-2.3 times longer lag phases. Both materials, PLA and the PLA/PCL blend, were only extensively digested when pretreated, yielding about 360-380 NmL CH4 per gram of material fed. Unpretreated PLA-based materials showed nearly zero methanization under the timeframe and experimental conditions tested. Overall, the results suggested that alkaline pretreatment can help to enhance the methanization kinetics of bioplastics.

Unlocking the high-rate continuous performance of fermentative hydrogen bioproduction from fruit and vegetable residues by modulating hydraulic retention time.

Harnessing fruit-vegetable waste (FVW) as a resource to produce hydrogen via dark fermentation (DF) embraces the circular economy concept. However, there is still a need to upgrade continuous FVW-DF bioprocessing to enhance hydrogen production rates (HPR). This study aims to investigate the influence of the hydraulic retention time (HRT) on the DF of FVW by mixed culture. A stirred tank reactor under continuous mesophilic conditions was operated for 47 days with HRT stepwise reductions from 24 to 6 h, leading to organic loading rates between 47 and 188 g volatile solids (VS)/L-d. The optimum HRT of 9 h resulted in an unprecedented HPR from FVW of 11.8 NL/L-d, with a hydrogen yield of 95.6 NmL/g VS fed. Based on an overarching inspection of hydrogen production in conjunction with organic acids and carbohydrates analyses, it was hypothesized that the high FVW-to-biohydrogen conversion rate achieved was powered by lactate metabolism.

Influence of key operational parameters on biohydrogen production from fruit and vegetable waste via lactate-driven dark fermentation.

This study aims at investigating the influence of operational parameters on biohydrogen production from fruit-vegetable waste (FVW) via lactate-driven dark fermentation. Mesophilic batch fermentations were conducted at different pH (5.5, 6.0, 6.5, 7.0, and non-controlled), total solids (TS) contents (5, 7, and 9%) and initial cell biomass concentrations (18, 180, and 1800 mg VSS/L). Higher hydrogen yields and rates were attained with more neutral pH values and low TS concentrations, whereas higher biomass densities enabled higher production rates and avoided wide variations in hydrogen production. A marked lactate accumulation (still at neutral pH) in the fermentation broth was closely associated with hydrogen inhibition. In contrast, enhanced hydrogen productions matched with much lower lactate accumulations (even it was negligible in some fermentations) along with the acetate and butyrate co-production but not with carbohydrates removal. At pH 7, 5% TS, and 1800 mg VSS/L, 49.5 NmL-H2/g VSfed and 976.4 NmL-H2/L-h were attained.

Two-stage anaerobic digestion of food waste: Enhanced bioenergy production rate by steering lactate-type fermentation during hydrolysis-acidogenesis.

This study proposed a lactate-based two-stage anaerobic digestion (AD) process to enhance bioenergy production rate from food waste (FW) and investigated the effect of inoculum addition and culture pH on hydrolysis-acidogenesis and further methanization. A series of batch fermentations were performed with an enriched lactate-producing consortium and without inoculum addition under controlled (5.7) and uncontrolled pH (initial 6.7) conditions. The interplay between the studied factors dictated the fate of lactate, particularly if it is produced and accumulated in the fermentation broth or is consumed by butyrogenic bacteria. Only the self-fermentation of FW with uncontrolled pH resulted in lactate accumulation (0.2 g/g volatile solid (VS) fed) with limited off-gas production (0.32 NL/L) and VS losses (≈16%). Such lactate-rich broth was successfully digested through biochemical methane potential tests, resulting in a maximum bioenergy production rate of 2891 MJ/ton-VS fed per day, which was two-fold higher compared to that achieved by one-stage AD.

Biodegradation of bioplastics under aerobic and anaerobic aqueous conditions: Kinetics, carbon fate and particle size effect.

The biodegradation of PHB, PHBV, PBS, PBAT, PCL, PLA, and a PLA-PCL blend was compared under aerobic and anaerobic aqueous conditions assessing biodegradation kinetics, extent, carbon fate and particle size influence (in the range of 100-1000 µm). Under standard test conditions, PHB and PBHV were biodegraded anaerobically (83.9 ± 1.3% and 81.2 ± 1.7%, respectively) in 77 days or aerobically (83.0 ± 1.6% and 87.4 ± 7.5%) in 117 days, while PCL was only biodegraded (77.6 ± 2.4%) aerobically in 177 days. Apparent biomass growth accounted for 10 to 30.5% of the total initial carbon depending on the bioplastic and condition. Maximum aerobic and anaerobic biodegradation rates were improved up to 331 and 405%, respectively, at the lowest particle size tested (100-250 µm). This study highlights the usefulness of analysing biodegradation kinetics and carbon fate to improve both the development and testing of biodegradable materials, and waste treatments in the context of a circular bioeconomy.

Magnetic Characterization by Scanning Microscopy of Functionalized Iron Oxide Nanoparticles.

This study aimed to systematically understand the magnetic properties of magnetite (Fe3O4) nanoparticles functionalized with different Pluronic F-127 surfactant concentrations (Fe3O4@Pluronic F-127) obtained by using an improved magnetic characterization method based on three-dimensional magnetic maps generated by scanning magnetic microscopy. Additionally, these Fe3O4 and Fe3O4@Pluronic F-127 nanoparticles, as promising systems for biomedical applications, were prepared by a wet chemical reaction. The magnetization curve was obtained through these three-dimensional maps, confirming that both Fe3O4 and Fe3O4@Pluronic F-127 nanoparticles have a superparamagnetic behavior. The as-prepared samples, stored at approximately 20 °C, showed no change in the magnetization curve even months after their generation, resulting in no nanoparticles free from oxidation, as Raman measurements have confirmed. Furthermore, by applying this magnetic technique, it was possible to estimate that the nanoparticles' magnetic core diameter was about 5 nm. Our results were confirmed by comparison with other techniques, namely as transmission electron microscopy imaging and diffraction together with Raman spectroscopy. Finally, these results, in addition to validating scanning magnetic microscopy, also highlight its potential for a detailed magnetic characterization of nanoparticles.

A review on the factors influencing biohydrogen production from lactate: The key to unlocking enhanced dark fermentative processes.

Dark fermentation (DF) is one of the most promising biological methods to produce bio-hydrogen and other value added bio-products from carbohydrate-rich wastes and wastewater. However, process instability and low hydrogen production yields and rates have been highlighted as the major bottlenecks preventing further development. Numerous studies have associated such concerns with the inhibitory activity of lactate-producing bacteria (LAB) against hydrogen producers. However, an increasing number of studies have also shown lactate-based metabolic pathways as the prevailing platform for hydrogen production. This opens a vast potential to develop new strategies to deal with the "Achilles heel" of DF - LAB overgrowth - while untapping high-performance DF. This review discusses the key factors influencing the lactate-driven hydrogen production, paying particular attention to substrate composition, the operating conditions, as well as the microbiota involved in the process and its potential functionality and related biochemical routes. The current limitations and future perspectives in the field are also presented.

Scanning Magnetic Microscope Using a Gradiometric Configuration for Characterization of Rock Samples.

Scanning magnetic microscopy is a tool that has been used to map magnetic fields with good spatial resolution and field sensitivity. This technology has great advantages over other instruments; for example, its operation does not require cryogenic technology, which reduces its operational cost and complexity. Here, we presented a spatial domain technique based on an equivalent layer approach for processing the data set produced by magnetic microscopy. This approach estimated a magnetic moment distribution over a fictitious layer composed by a set of dipoles located below the observation plane. For this purpose, we formulated a linear inverse problem for calculating the magnetic vector and its amplitude. Vector field maps are valuable tools for the magnetic interpretation of samples with a high spatial variability of magnetization. These maps could provide comprehensive information regarding the spatial distribution of magnetic carriers. In addition, this approach might be useful for characterizing isolated areas over samples or investigating the spatial magnetization distribution of bulk samples at the micro and millimeter scales. This technique could be useful for many applications that require samples that need to be mapped without a magnetic field at room temperature, including rock magnetism.

Characterizing Complex Mineral Structures in Thin Sections of Geological Samples with a Scanning Hall Effect Microscope.

We improved a magnetic scanning microscope for measuring the magnetic properties of minerals in thin sections of geological samples at submillimeter scales. The microscope is comprised of a 200 µm diameter Hall sensor that is located at a distance of 142 µm from the sample; an electromagnet capable of applying up to 500 mT DC magnetic fields to the sample over a 40 mm diameter region; a second Hall sensor arranged in a gradiometric configuration to cancel the background signal applied by the electromagnet and reduce the overall noise in the system; a custom-designed electronics system to bias the sensors and allow adjustments to the background signal cancelation; and a scanning XY stage with micrometer resolution. Our system achieves a spatial resolution of 200 µm with a noise at 6.0 Hz of 300 nTrms/(Hz)1/2 in an unshielded environment. The magnetic moment sensitivity is 1.3 × 10-11 Am². We successfully measured the representative magnetization of a geological sample using an alternative model that takes the sample geometry into account and identified different micrometric characteristics in the sample slice.

Intelligent multiagent coordination based on reinforcement hierarchical neuro-fuzzy models.

This paper presents the research and development of two hybrid neuro-fuzzy models for the hierarchical coordination of multiple intelligent agents. The main objective of the models is to have multiple agents interact intelligently with each other in complex systems. We developed two new models of coordination for intelligent multiagent systems, which integrates the Reinforcement Learning Hierarchical Neuro-Fuzzy model with two proposed coordination mechanisms: the MultiAgent Reinforcement Learning Hierarchical Neuro-Fuzzy with a market-driven coordination mechanism (MA-RL-HNFP-MD) and the MultiAgent Reinforcement Learning Hierarchical Neuro-Fuzzy with graph coordination (MA-RL-HNFP-CG). In order to evaluate the proposed models and verify the contribution of the proposed coordination mechanisms, two multiagent benchmark applications were developed: the pursuit game and the robot soccer simulation. The results obtained demonstrated that the proposed coordination mechanisms greatly improve the performance of the multiagent system when compared with other strategies.

Classification of vocal aging using parameters extracted from the glottal signal.

This article proposes and evaluates a method to classify vocal aging using artificial neural network (ANN) and support vector machine (SVM), using the parameters extracted from the speech signal as inputs. For each recorded speech, from a corpus of male and female speakers of different ages, the corresponding glottal signal is obtained using an inverse filtering algorithm. The Mel Frequency Cepstrum Coefficients (MFCC) also extracted from the voice signal and the features extracted from the glottal signal are supplied to an ANN and an SVM with a previous selection. The selection is performed by a wrapper approach of the most relevant parameters. Three groups are considered for the aging-voice classification: young (aged 15-30 years), adult (aged 31-60 years), and senior (aged 61-90 years). The results are compared using different possibilities: with only the parameters extracted from the glottal signal, with only the MFCC, and with a combination of both. The results demonstrate that the best classification rate is obtained using the glottal signal features, which is a novel result and the main contribution of this article.

New focus of active transmission of Chagas disease in indigenous populations in the Peruvian Amazon basin.

INTRODUCTION: Several cases of acute Chagas disease (ACD) have been reported in the Peruvian Amazon basin. METHODS: The objective was to describe and investigate 6 ACD cases in children from indigenous Amazon communities in the province of Datem del Marañón in Loreto department (2006-2010). RESULTS: The mean age was 3.6 years. All patients had fever, 4/6 hepatomegaly, 2/6 splenomegaly, and 5/6 had trypomastigotes of Trypanosoma cruzi on thick smears. The fatality rate was 33.3%. Rhodnius pictipes and Rhodnius robustus adults were found inside the homes and in the peri-domiciles. CONCLUSIONS: All cases reported were isolated cases. We report a new focus of ACD in indigenous populations.

New focus of active transmission of Chagas disease in indigenous populations in the Peruvian Amazon basin

Introduction Several cases of acute Chagas disease (ACD) have been reported in the Peruvian Amazon basin. Methods The objective was to describe and investigate 6 ACD cases in children from indigenous Amazon communities in the province of Datem del Marañón in Loreto department (2006-2010). Results The mean age was 3.6 years. All patients had fever, 4/6 hepatomegaly, 2/6 splenomegaly, and 5/6 had trypomastigotes of Trypanosoma cruzi on thick smears. The fatality rate was 33.3%. Rhodnius pictipes and Rhodnius robustus adults were found inside the homes and in the peri-domiciles. Conclusions All cases reported were isolated cases. We report a new focus of ACD in indigenous populations. .

28S-ribosomal RNA is superior to glyceraldehyde-3-phosphate dehydrogenase as a RNA reference gene in p53-deficient mice with unilateral ureteral obstruction.

Although there are many kinds of reference genes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has been commonly used by many researchers to assess the amount and integrity of RNA transcripts in RNA studies including Northern blot and reverse transcription real time-PCR. Although some data suggest that GAPDH could be inconstant in their situations or experiments, there is limited evidence that GAPDH expression is influenced by conditions of experiment, especially in mouse kidney model with unilateral ureteral obstruction (UUO). Therefore, the establishment of excellent reference gene according to the tissue types or conditions of experiment is a bottom line for the RNA study. Here we compared the expression of GAPDH with 28S rRNA gene by Northern blot analysis in the p53-deficient mice with UUO. We observed that GAPDH mRNA levels in ligated kidneys were significantly lower than those in contralateral kidneys, especially after postoperative day 15. In contrast, 28S rRNA levels were constant among control, ligated and contralateral kidneys. We also demonstrated that 28S rRNA signal was proportional to the amount of RNA loaded. In conclusion, these data indicate that much caution should be taken when using GAPDH as a RNA reference gene and 28S rRNA is an excellent gene for the RNA study in p53-deficient mice with UUO.

Smad3 signaling critically regulates fibroblast phenotype and function in healing myocardial infarction.

RATIONALE: Cardiac fibroblasts are key effector cells in the pathogenesis of cardiac fibrosis. Transforming growth factor (TGF)-beta/Smad3 signaling is activated in the border zone of healing infarcts and induces fibrotic remodeling of the infarcted ventricle contributing to the development of diastolic dysfunction. OBJECTIVE: The present study explores the mechanisms responsible for the fibrogenic effects of Smad3 by dissecting its role in modulating cardiac fibroblast phenotype and function. METHODS AND RESULTS: Smad3 null mice and corresponding wild-type controls underwent reperfused myocardial infarction protocols. Surprisingly, reduced collagen deposition in Smad3-/- infarcts was associated with increased infiltration with myofibroblasts. In vitro studies demonstrated that TGF-beta1 inhibited murine cardiac fibroblast proliferation; these antiproliferative effects were mediated via Smad3. Smad3-/- fibroblasts were functionally defective, exhibiting impaired collagen lattice contraction when compared with wild-type cells. Decreased contractile function was associated with attenuated TGF-beta-induced expression of alpha-smooth muscle actin. In addition, Smad3-/- fibroblasts had decreased migratory activity on stimulation with serum, and exhibited attenuated TGF-beta1-induced upregulation of extracellular matrix protein synthesis. Upregulation of connective tissue growth factor, an essential downstream mediator in TGF-beta-induced fibrosis, was in part dependent on Smad3. Connective tissue growth factor stimulation enhanced extracellular matrix protein expression by cardiac fibroblasts in a Smad3-independent manner. CONCLUSIONS: Disruption of Smad3 results in infiltration of the infarct with abundant hypofunctional fibroblasts that exhibit impaired myofibroblast transdifferentiation, reduced migratory potential, and suppressed expression of fibrosis-associated genes.

Evidencia serológica de ehrlichiosis humana en Ancash, Perú / Serological evidence of human ehrlichiosis in Ancash, Perú

Se desarrolló y estandarizó una prueba de inmunofluorescencia indirecta para detección de IgG e IgTotal para el diagnóstico de Ehrlichiosis humana. Se utilizó como antígeno, a células DH82 infectadas con Ehrlichia chaffeensis cepa Sapulpa, se consideró una dilución de 1/64 como positivo. Se evaluó 130 sueros de pacientes febriles negativos para Rickettsiosis y enfermedad de Carrión procedentes de Ancash, que ingresaron al Instituto Nacional de Salud entre los años 2004 a 2006. Se encontró que 12 (9,2%) sueros fueron positivos a Ehrlichiosis. Teniendo en cuenta que es una enfermedad emergente y con el desarrollo de esta prueba, es recomendable iniciar estudios epidemiológicos y de vigilancia de la Ehrlichiosis en el Perú.

We developed and standardized an indirect immunofluorescence test for detection of IgG and IgTotal for diagnosing human Ehrlichiosis. It was used as antigen to DH82 infected cells with Ehrlichia chaffeensis Sapulpa strain; it was considered a dilution of 1/64 as positive. We evaluated sera from 130 febrile patients negative for Rickettsiosis and Carrion disease from Ancash, who entered at Instituto Nacional de Salud (Lima, Peru) between 2004 and 2006. We found that 12 (9.2%) sera were positive for Ehrlichiosis. Given that Ehrlichiosis is an emerging disease and with the development of this test, it should start monitoring and epidemiological studies of Ehrlichiosis in Peru.

Characterization of the inflammatory and fibrotic response in a mouse model of cardiac pressure overload.

Myocardial fibrosis is an integral component of most cardiac pathologic conditions and contributes to the development of both systolic and diastolic dysfunction. Because of the availability of genetically manipulated animals, mouse models are essential for understanding the mechanisms involved in the pathogenesis of cardiac fibrosis. Accordingly, we characterized the inflammatory and fibrotic response in a mouse model of cardiac pressure overload due to transverse aortic constriction (TAC). Following TAC, mouse hearts exhibited induction of chemokines and proinflammatory cytokines, associated with macrophage, but not neutrophil, infiltration. Induction of inflammatory cytokines was followed by a late upregulation of transforming growth factor (TGF)-beta isoforms, activation of the Smad2/3 and Smad1/5 pathways, induction of matricellular proteins, and deposition of collagen. Inflammatory activity decreased after 28 days of TAC; at this timepoint established fibrosis was noted, accompanied by ventricular dilation and systolic dysfunction. Late induction of inhibitory mediators, such as TGF-beta, may play an essential role in the transition from inflammation to fibrosis by suppressing inflammatory gene synthesis while inducing matrix deposition. Our findings identify molecular mediators and pathways with a potential role in cardiac fibrosis laying the foundations for studies exploring the pathogenesis of fibrotic cardiac remodeling using genetically targeted mice.