Nanoscale morphology, optical dynamics and gas sensor of porous silicon

We investigated the multifaceted gas sensing properties of porous silicon thin films electrodeposited onto (100) oriented P-type silicon wafers substrates. Our investigation delves into morphological, optical properties, and sensing capabilities, aiming to optimize their use as efficient gas sensors. Morphological analysis revealed the development of unique surfaces with distinct characteristics compared to untreated sample, yielding substantially rougher yet flat surfaces, corroborated by Minkowski Functionals analysis. Fractal mathematics exploration emphasized that despite increased roughness, HF/ethanol-treated surfaces exhibit flatter attributes compared to untreated Si sample. Optical approaches established a correlation between increased porosity and elevated localized states and defects, influencing the Urbach energy value. This contributed to a reduction in steepness values, attributed to heightened dislocations and structural disturbances, while the transconductance parameter decreases. Simultaneously, porosity enhances the strength of electron‒phonon interaction. The porous silicon thin films were further tested as effective gas sensors for CO2 and O2 vapors at room temperature, displaying notable changes in electrical resistance with varying concentrations. These findings bring a comprehensive exploration of some important characteristics of porous silicon surfaces and established their potential for advanced industrial applications.

Associating Physical and Photocatalytic Properties of Recyclable and Reusable Blast Furnace Dust Waste

Blast furnace dust waste (BFDW) proved efficient as a photocatalyst for the decolorization of methylene blue (MB) dye in water. Structural analysis unequivocally identified α-Fe2O3 as the predominant phase, constituting approximately 92%, with a porous surface showcasing unique 10-30 nm agglomerated nanoparticles. Chemical and thermal analyses indicated surface-bound water and carbonate molecules, with the main phase's thermal stability up to 900 °C. Electrical conductivity analysis revealed charge transfer resistance values of 616.4 Ω and electrode resistance of 47.8 Ω. The Mott-Schottky analysis identified α-Fe2O3 as an n-type semiconductor with a flat band potential of 0.181 V vs. Ag/AgCl and a donor density of 1.45 × 1015 cm-3. The 2.2 eV optical bandgap and luminescence stem from α-Fe2O3 and weak ferromagnetism arises from structural defects and surface effects. With a 74% photocatalytic efficiency, stable through three photodegradation cycles, BFDW outperforms comparable waste materials in MB degradation mediated by visible light. The elemental trapping experiment exposed hydroxyl radicals (OH•) and superoxide anions (O2-•) as the primary species in the photodegradation process. Consequently, iron oxide-based BFDW emerges as an environmentally friendly alternative for wastewater treatment, underscoring the pivotal role of its unique physical properties in the photocatalytic process.

Evaluating the roughness dynamics of kefir biofilms grown on Amazon cupuaçu juice: a monofractal and multifractal approach

We conducted a comprehensive analysis of the surface microtexture of kefir biofilms grown on Theobroma grandiflorum Shum (cupuaçu) juice using atomic force microscopy. Our goal was to investigate the unique monofractal and multifractal spatial patterns of these biofilms to complement the existing limited literature. The biofilms were prepared dispersing four different concentrations of kefir grains in cupuaçu juice. Our morphological analysis showed that the surface of the obtained biofilms is essentially formed by the presence of cupuaçu fibers and microorganisms like lactobacilli and yeast. The topographic height-based parameter analysis reveals that there is a dependence between surface roughness and the concentration of kefir grains used. The strongly anisotropic well-centralized topographical height distribution of the biofilms also exhibited a quasi-symmetrical and platykurtic pattern. The biofilms exhibit comparable levels of spatial complexity, surface percolation and surface homogeneity, which can be attributed to their similar topographic uniformity. This aspect was further supported by the presence of similar multifractality in the biofilms, suggesting that despite their varying topographic roughness, their vertical growth dynamics follow a similar pattern. Our findings demonstrate that the surface roughness of kefir biofilms cultivated on cupuaçu juice is influenced by the concentration of kefir grains in the precursor solution. However, this dependence follows a consistent pattern across different concentrations. Graphical Abstract.

Morphological and fractal features of cancer cells anchored on composite layers based on magnesium-doped hydroxyapatite loaded in chitosan matrix

In the present study, we report the development and characterization of composite layers (by spin coating) based on magnesium-doped hydroxyapatite in a chitosan matrix, containing human osteosarcoma MG63 cells anchored. Studies regarding the biocompatibility of the composite layers were performed with the aid of a MTT (3-4,5-Dimethylthiazol 2,5-diphenyltetrazolium bromide) assay. The data determined that the composite layers did not inhibit the growth and adhesion of MG63 cells to their surfaces exhibiting good biocompatibility properties. Furthermore, the attachment and development of MG63 cells on the surface of MgHApCh composite layers were investigated using atomic force microscopy (AFM). AFM topographical maps emphasized that the HApCh and 8MgHApCh composite layers surface promoted the attachment and proliferation of MG63 cells on their surface. Meanwhile, in the case of 30MgHApCh layers incubated for 48 h, a slight modification of the morphological features of the MG63 cells. In addition, the effects of the composite layers against Candida albicans ATCC 10231 were also evaluated. The data results from the in vitro antifungal assay depicted that the composite layers successfully inhibited the growth of the fungal cells onto their surface. Morphological and fractal analyses unveil cancer cell surfaces on Mg-containing composite layers with intricate 3D patterns, driven by high-frequency components. Their remarkable complexity and roughness arises from a strong multifractal nature, supporting more effective vertical growth compared to Si and HApCh surfaces. The cell viability reduced of uncoated Si surface is highlighted by its less intense 3D pattern growth. Our results show that the uncoated Si surface promotes lower viability of MG63 cancer cells, with less rough and complex 3D spatial patterns.

Advanced nano-texture, optical bandgap, and Urbach energy analysis of NiO/Si heterojunctions

Due to the large number of industrial applications of transparent conductive oxides (TCOs), this study focuses on one of the most important metal oxides. The RF-magnetron sputtering method was used to fabricate NiO thin films on both quartz and silicon substrates at room temperature under flow of Argon and Oxygen. The sputtered samples were annealed in N₂ atmosphere at 400, 500, and 600 °C for 2 hours. Using the AFM micrographs and WSXM 4.0 software, the basic surface parameters, including root mean square roughness, average roughness, kurtosis, skewness, etc., were computed. Advanced surface parameters were obtained by the Shannon entropy through a developed algorithm, and the power spectral density and fractal succolarity were extracted by related methods. Optical properties were studied using a transmittance spectrum to achieve the optical bandgap, absorption coefficient, Urbach energy, and other optical parameters. Photoluminescence properties also showed interesting results in accordance with optical properties. Finally, electrical characterizations and I-V measurements of the NiO/Si heterojunction device demonstrated that it can be used as a good diode device.

Evaluating structural, morphological, and multifractal aspects of n-ZnO/p-ZnO homojunctions and n-ZnO/p-NiO heterojunctions

We have investigated the evolution of the structure and surface morphology of n-ZnO/p-ZnO homojunctions and n-ZnO/p-NiO heterojunctions transparent structures deposited by radio frequency-sputtering on quartz (Q)/ITO substrates. X-ray diffraction (XRD) analysis of the as-deposited and annealed ZnO, n-ZnO/p-NiO/Q/ITO, and n-ZnO/p-ZnO/Q/ITO thin films showed that ZnO had a wurtzite hexagonal structure and (002) preferred growth direction. The annealing temperature played a key role in improving the crystalline structure of the films, as evidenced by the changes in the intensity and position of the XRD (002) peak. Morphological analysis revealed that the roughness of the film varies with increasing annealing temperature. Particle size dictates the vertical growth of p-ZnO homojunctions, while particle shape dictated the p-NiO heterojunctions growth. Fractal analysis showed that p-ZnO homojunctions have similar spatial complexity, surface percolation, and topographical uniformity and are dominated by low dominant frequencies. Moreover, a robust multifractal character was observed, where n-ZnO/p-ZnO homojunctions follow similar vertical growth dynamics, which differed from the n-ZnO/p-NiO heterojunctions growth dynamics. These results prove that annealing temperature plays a key role in the n-ZnO/p-ZnO homojunctions and n-ZnO/p-NiO heterojunctions structure, surface morphology, and vertical growth dynamics.

Insights into the Fe3+ Doping Effects on the Structure and Electron Distribution of Cr2O3 Nanoparticles

Herein, we carefully investigated the Fe3+ doping effects on the structure and electron distribution of Cr2O3 nanoparticles using X-ray diffraction analysis (XRD), maximum entropy method (MEM), and density functional theory (DFT) calculations. We showed that increasing the Fe doping induces an enlargement in the axial ratio of c/a, which is associated with an anisotropic expansion of the unit cell. We found that as Fe3+ replaces Cr in the Cr2O3 lattice, it caused a higher interaction between the metal 3d states and the oxygen 2p states, which led to a slight increase in the Cr/Fe-O1 bond length followed by an opposite effect for the Cr/Fe-O2 bonds. Our results also suggest that the excitations characterize a well-localized bandgap region from occupied Cr d to unoccupied Fe d states. The Cr2O3 and Fe-doped Cr2O3 nanoparticles behave as Mott-Hubbard insulators due to their band gap being in the d-d gap, and Cr 3d orbitals dominate the conduction band. These findings suggest that the magnitude and the character of the electronic density near the O atom bonds in Cr2O3 nanoparticles are modulated by the Cr-Cr distances until its stabilization at the induced quasi-equilibrium of the Cr2O3 lattice when the Fe3+ doping values reaches the saturation level range.

Morphological and multifractal properties of Cr thin films deposited onto different substrates

In this study, the morphological properties and micro-roughness of chromium thin film prepared by thermal evaporation technique and confirmed via EDS analysis are examined on different substrates of BK7, Silicon (Si), and glass using atomic force microscope analysis (AFM). Analysis of amplitude parameters, Minkowski functionals, and films' spatial microtexture extracted from AFM analysis showed the difference between glass substrate and the other two (BK7 and Si) substrates for the growth of chromium thin films. In addition, we observed robust signatures of multifractality of the Cr thin films deposited on all substrates we studied. Moreover, we highlight that the Glass substrates displayed the strongest multifractality indicating that such samples present space filling properties distributed over more spatial scales than the samples of BK7 and Si.

Exploiting the Physicochemical and Antimicrobial Properties of PHB/PEG and PHB/PEG/ALG-e Blends Loaded with Ag Nanoparticles

Poly(3-hydroxybutyrate) (PHB)-based films containing Poly(ethylene glycol) (PEG), esterified sodium alginate (ALG-e) and polymeric additives loaded with Ag nanoparticles (AgNPs) were obtained by a conventional casting method. AgNPs were produced in aqueous suspension and added to polymeric gels using a phase exchange technique. Composite formation was confirmed by finding the Ag peak in the XRD pattern of PHB. The morphological analysis showed that the inclusion of PEG polymer caused the occurrence of pores over the film surface, which were overshadowed by the addition of ALG-e polymer. The PHB functional groups were dominating the FTIR spectrum, whose bands associated with the crystalline and amorphous regions increased after the addition of PEG and ALG-e polymers. Thermal analysis of the films revealed a decrease in the degradation temperature of PHB containing PEG/AgNPs and PEG/ALG-e/AgNPs, suggesting a catalytic effect. The PHB/PEG/ALG-e/AgNPs film combined the best properties of water vapor permeability and hydrophilicity of the different polymers used. All samples showed good antimicrobial activity in vitro, with the greater inhibitory halo observed for the PEG/PEG/AgNPs against Gram positive S. aureus microorganisms. Thus, the PHB/PEG/ALG-e/AgNPs composite demonstrated here is a promising candidate for skin wound healing treatment.

Antiferromagnet-Ferromagnet Transition in Fe1-xCuxNbO4

Iron niobates, pure and substituted with copper (Fe_1-xCu_xNbO₄ with x = 0-0.15), were prepared by the solid-state method and characterized by X-ray diffraction, Raman spectroscopy, and magnetic measurements. The results of the structural characterizations revealed the high solubility of Cu ions in the structure and better structural stability compared to the pure sample. The analysis of the magnetic properties showed that the antiferromagnetic-ferromagnetic transition was caused by the insertion of Cu²⁺ ions into the FeNbO₄ structure. The pure FeNbO₄ structure presented an antiferromagnetic ordering state, with a Néel temperature of approximately 36.81K. The increase in substitution promoted a change in the magnetic ordering, with the state passing to a weak ferromagnetic order with a transition temperature (T_c) higher than the ambient temperature. The origin of the ferromagnetic ordering could be attributed to the increase in super-exchange interactions between Fe/Cu ions in the Cu²⁺-O-Fe³⁺ chains and the formation of bound magnetic polarons in the oxygen vacancies.

Molecularly Imprinted Membrane Produced by Electrospinning for β-Caryophyllene Extraction

Molecularly imprinted membrane of β-caryophyllene (MIM-βCP) was fabricated incorporating β-caryophyllene molecularly imprinted polymer nanoparticles (βCP-NP) into polycaprolactone (PCL) fibers via electrospinning. The βCP-NP were synthesized by precipitation polymerization using the βCP as a template molecule and acrylic acid as a functional monomer in the proportion of 1:4 mol, respectively. Atomic force microscopy images and X-ray diffraction confirmed the nanoparticles' incorporation into MIM-βCP. MIM-βCP functionalization was evaluated by gas chromatography. The binding capacity was 1.80 ± 0.05 μmol/cm², and the selectivity test was performed with a mixing solution of βCP and caryophyllene oxide, as an analog compound, that extracted 77% of the βCP in 5 min. The electrospun MIM-βCP can be used to detect and extract the βCP, applications in the molecular sieve, and biosensor production and may also contribute as an initial methodology to enhance versatile applications in the future, such as in the treatment of skin diseases, filters for extraction, and detection of βCP to prevent counterfeiting of commercial products, and smart clothing with insect-repellent properties.

Investigating the Correlation between the Microstructure and Electrical Properties of FeSbO4 Ceramics

FeSbO4 powder was prepared using the solid-state reaction method in this work. Afterward, the dense and porous ceramics were obtained by sintering the pressed powder calcined at temperatures of 900 and 1000 °C for 4 h. Rietveld profile analysis of the X-ray powder diffraction data showed that FeSbO4 adopts the trirutile-type structure (space group P42/mnm, with a ≅ 4.63 Å and c ≅ 9.23 Å). SEM images showed that the powder calcined at 900 °C after being sintered at 1200 °C resulted in ceramics of higher crystallinity, larger grains, and consequently, low porosity. The dielectric properties were measured in the frequency range of 10−1 Hz−1 MHz as a function of temperature (25−250 °C). The real (σ′) and imaginary (σ″) parts of the complex conductivity increase with rising annealing temperature for both samples. The real conductivity in the AC region for 𝑓 = 100 kHz was 1.59×10−6 S·cm−1 and 7.04×10−7 S·cm−1 for the ceramic samples obtained from the powder calcined at 900 (C-900) and 1000 °C (C-1000), respectively. Furthermore, the dielectric constants (k′) measured at room temperature and f=100 kHz were 13.77 (C-900) and 6.27 (C-1000), while the activation energies of the grain region were Ea = 0.53 eV and Ea = 0.49 eV, respectively. Similar activation energy (Ea = 0.52 eV and 0.49 eV) was also obtained by the brick-layer model and confirmed by the adjustment of activation energy by DC measurements which indicated an absence of the porosity influence on the parameter. Additionally, loss factor values were obtained to be equal to 3.8 (C-900) and 5.99 (C-1000) for measurements performed at 100 Hz, suggesting a contribution of the conductivity originated from the combination or accommodation of the pores in the grain boundary region. Our results prove that the microstructural factors that play a critical role in the electrical and dielectric properties are the average grain size and the porosity interspersed with the grain boundary region.

Evaluation of the Photocatalytic Activity of Distinctive-Shaped ZnO Nanocrystals Synthesized Using Latex of Different Plants Native to the Amazon Rainforest

ZnO nanocrystals with three different morphologies have been synthesized via a simple sol-gel-based method using Brosimum parinarioides (bitter Amapá) and Parahancornia amapa (sweet Amapá) latex as chelating agents. X-ray diffraction (XRD) and electron diffraction patterns (SAED) patterns showed the ZnO nanocrystals were a pure hexagonal wurtzite phase of ZnO. XRD-based spherical harmonics predictions and HRTEM images depicted that the nanocrystallites constitute pitanga-like (~15.8 nm), teetotum-like (~16.8 nm), and cambuci-like (~22.2 nm) shapes for the samples synthesized using bitter Amapá, sweet Amapá, and bitter/sweet Amapá chelating agent, respectively. The band gap luminescence was observed at ~2.67-2.79 eV along with several structural defect-related, blue emissions at 468-474 nm (V_O, V_Zn, Zn_i), green emissions positioned at 513.89-515.89 (h-VO+), and orange emission at 600.78 nm (VO+-VO++). The best MB dye removal efficiency (85%) was mainly ascribed to the unique shape and oxygen vacancy defects found in the teetotum-like ZnO nanocrystals. Thus, the bitter Amapá and sweet Amapá latex are effective chelating agents for synthesizing distinctive-shaped ZnO nanocrystals with highly defective and remarkable photocatalytic activity.

Surface aspects and multifractal features of 3D spatial patterns of low-cost Amazon açaí-loaded kefir microbial films

In this study, açaí-loaded kefir microbial films obtained in solutions containing demerara sugar, a low-cost and relatively organic sugar, were prepared. Environmental scanning electron microscopy (ESEM), atomic force microscopy (AFM), stereometric and multifractal analyses were applied to study the influence of the concentration of açaí over the surface morphology as well as its multifractal nature. The ESEM and AFM images showed that low concentrations of acai berry form surface covered by bacteria, while higher concentrations promote yeast growth. The autocorrelation function suggested that the degree of surface anisotropy changes as the concentration of açaí increases, while the Minkowski Functionals confirmed that the sample with the highest content has a different morphology than the samples containing 10-40 ml. The multifractal analysis revealed that the surfaces have a strong multifractal behavior, where the multifractal singularity strength was higher in the sample containing the highest concentration of açaí. The sample with the highest concentration was then mapped to have a greater vertical growth of its spatial patterns. These results prove that image analysis using mathematical tools can be very useful for the characterization of biological-based systems for application in the biomedicine field. We characterized the micromorphology of the 3D surface of the kefir biofilms associated with Acai extract. The 3D surface analysis of the samples was performed using by environmental scanning electron microscope and atomic force microscopy. We determined the multifractal and Minkowski Functionals of the analyzed samples.

Surface dynamics, fractal features, and micromorphology analysis of kefir biofilms

We introduce a study of image analysis of kefir biofilms associated with Acai extract prepared by fermentation of fresh kefir grains natural. Atomic force microscopy data were studied, aiming to understand how the concentration of acai berry (Euterpe oleracea Mart.) influences the surface morphology as well as the texture complexity, evaluated by the fractal dimension. The results showed that the superficial morphology was affected by the increase of Acai concentration in the biofilms, as well as the fractal dimension. It has also been observed that the surface of the biofilm presented saturation when concentration changes from 40 to 60 ml. On the other hand, it was observed that the intermediate sample produced with 20 ml of acai berry seems to be the best point for biofilms production that can serve as a skin dressing since other studies related to mechanical properties and in vitro and in vivo tests can confirm this applicability. Thus, the characterization of the surface morphology of kefir biofilms by the evaluation of surface statistical parameters and fractal geometry may provide promising results regarding the applicability of these films. RESEARCH HIGHLIGHTS: We characterized the structural complexity of the 3-D surface of the kefir biofilms associated with açaí extract. The 3-D surface analysis of the samples was performed using an atomic force microscope operating in contact mode. We determined the stereometric and fractal dimension of the analyzed samples.

Epicardial slices: an innovative 3D organotypic model to study epicardial cell physiology and activation

The epicardium constitutes an untapped reservoir for cardiac regeneration. Upon heart injury, the adult epicardium re-activates, leading to epithelial-to-mesenchymal transition (EMT), migration, and differentiation. While interesting mechanistic and therapeutic findings arose from lower vertebrates and rodent models, the introduction of an experimental system representative of large mammals would undoubtedly facilitate translational advancements. Here, we apply innovative protocols to obtain living 3D organotypic epicardial slices from porcine hearts, encompassing the epicardial/myocardial interface. In culture, our slices preserve the in vivo architecture and functionality, presenting a continuous epicardium overlaying a healthy and connected myocardium. Upon thymosin β4 treatment of the slices, the epicardial cells become activated, upregulating epicardial and EMT genes, resulting in epicardial cell mobilization and differentiation into epicardial-derived mesenchymal cells. Our 3D organotypic model enables to investigate the reparative potential of the adult epicardium, offering an advanced tool to explore ex vivo the complex 3D interactions occurring within the native heart environment.

The vascular clock: a new insight into endothelial cells and pericytes crosstalk

Background/Introduction

Circadian rhythms, defined as biological oscillations with a period of circa 24h, regulate many physiological processes in the cardiovascular system, such as vascular function, vascular tone, blood pressure, heart rate and thrombus formation [1]. The vasculature responds to the main pacemaker located in the brain, but it also possesses its own clock. Indeed, a molecular clock has been identified in endothelial cells (EC) and smooth muscle cells (SMC). The disruption of the circadian clock profoundly affects cardiovascular functionality with adverse cardiovascular events such as myocardial infarction or stroke showing a 24h rhythmicity with a peak incidence in the early morning. Among several mechanisms affected by circadian dysregulation, angiogenesis plays a fundamental role in homeostasis and development of new blood vessels. EC and pericytes (PC) are the two main cell populations in the capillaries, and their physical and paracrine interaction drives and regulates the sprouting. However, the presence and the role of circadian rhythms in pericytes and whether the molecular clock affects the endothelial/pericyte interactions remain unexplored.

Purpose

The aim of this study is to identify a molecular clock in human vascular pericytes and elucidate the impact of the circadian clock on the formation of new blood vessels.

Methods

Human primary PC were synchronised and the rhythmicity of clock genes measured by luminescence, immunofluorescence, and qPCR. Synchronised PC were co-cultured with Bmal1::LUC human primary EC. The effect of PC synchronisation and circadian clock disruption by shRNA on EC clock genes and angiogenic potential were measured by luminescence and Matrigel assay, respectively. A macroporous polyurethane scaffold was developed for 3D co-cultures.

Results

PC presented rhythmic expression of the principal circadian genes with a circa 24h period but in our experimental setting, EC did not show circadian rhythmicity. Synchronised PC supported the rhythmic expression of the clock gene Bmal1 in EC in a contact co-culture system, suggesting a secondary form of EC molecular clock regulation. Non-contact co-cultures failed to synchronise EC. Furthermore, when the clock was disrupted in PC, their capacity to support EC's tube-forming capacity on Matrigel was impaired; clock disruption in EC did not affect angiogenesis, supporting the hypothesis that a disrupted clock in perivascular cells affects angiogenesis. In a 3D tissue engineering scaffold seeded with both EC and PC, the synchronisation of the clock led to the development of organised vascular-like structures around the scaffold's pores, as compared to the non-synchronised condition where cells appeared disorganised.

Conclusion

This study defines for the first time the existence of an endogenous molecular circadian clock in perivascular cells and suggests implications for circadian clock synchronisation in physiological and therapeutic angiogenesis.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): University of Surrey Doctoral CollegeUniversity of Surrey Bioprocess and Biochemical Engineering (BioProChem) Group.

Acute blockade of endogenous melatonin by Luzindole, with or without peripheral LPS injection, induces jejunal inflammation and morphological alterations in Swiss mice

This study investigated the acute blockade of endogenous melatonin (MLT) using Luzindole with or without systemic lipopolysaccharide (LPS) challenge and evaluated changes in inflammatory and oxidative stress markers in the mouse jejunum. Luzindole is an MT1/MT2 MLT receptor antagonist. Both receptors occur in the small intestine. Swiss mice were treated with either saline (0.35 mg/kg, ip), Luzindole (0.35 mg/kg, ip), LPS (1.25 mg/kg, ip), or Luzindole+LPS (0.35 and 1.25 mg/kg, ip, respectively). Jejunum samples were evaluated regarding intestinal morphometry, histopathological crypt scoring, and PAS-positive villus goblet cell counting. Inflammatory Iba-1, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, nuclear factor (NF)-kB, myeloperoxidase (MPO), and oxidative stress (NP-SHs, catalase, MDA, nitrate/nitrite) markers were assessed. Mice treated with Luzindole, LPS, and Luzindole+LPS showed villus height shortening. Crypt damage was worse in the LPS group. Luzindole, LPS, and Luzindole+LPS reduced the PAS-goblet cell labeling and increased Iba-1-immunolabelled cells compared to the saline group. Immunoblotting for IL-1β, TNF-α, and NF-kB was greater in the Luzindole group. The LPS-challenged group showed higher MPO activity than the saline and Luzindole groups. Catalase was reduced in the Luzindole and Luzindole+LPS groups compared to saline. The Luzindole group showed an increase in NP-SHs, an effect related to compensatory GSH activity. The acute blockade of endogenous MLT with Luzindole induced early changes in inflammatory markers with altered intestinal morphology. The other non-detectable deleterious effects of Luzindole may be balanced by the unopposed direct action of MLT in immune cells bypassing the MT1/MT2 receptors.

Stereometric analysis of Amazon rainforest Anacardium occidentale L. leaves

AFM, profilometry and SEM measurements on both sides of the Anacardium occidentale L. leaf reveal that ultrastructure presented some singularities due to their different morphologies and roughness. The advanced stereometry and power spectrum density of both sides of the Anacardium occidentale L. leaf were carefully studied. We use three different microscopy techniques such as scanning electron microscopy, profilometry, and atomic force microscopy for a complete description of the leaf surface morphology. The morphology of the adaxial and abaxial sides revealed a surface composed of striated cuticles and stomata cells, respectively. The height parameters obtained by profilometry revealed that the abaxial side was rougher. However, both sides presented similar Gaussian height distribution and asymmetry. The advanced stereometric parameters obtained by the topographic maps of AFM revealed that the two sides have some singularities due to their different morphologies and roughness, but with similar microtextures. However, average PSD spectra showed that adaxial and abaxial sides are dominated by relatively low and high spatial frequencies, showing that the microtextures, unlike what was shown in stereometric parameters, are different. These results revealed that leaves surface morphology under different aspects and scales and the quantitative parameters confirmed the different spatial patterns displayed, which can be of great interest for the study of the biological behavior of plants from their leaves.

3D micromorphology evaluation of kefir microbial films loaded with extract of Amazon rainforest fruit Cupuaçu

We performed qualitative and quantitative analysis of surfaces of kefir biofilms loaded with Amazon rainforest fruit extract. Scanning electron microscopy and atomic force microscopy were used to evaluate the micromorphology of the biofilms. The films surface displayed a lower density of microorganisms (∼ 0.061 microorganisms/μm²) for the lowest concentration of fruit extract, however, a greater density (∼0.220 microorganisms/μm²) was observed for the higher concentration. Height stereometric parameters revealed that the biofilms with the highest concentration presented the highest roughness. However, almost all the stereometric parameters related to texture showed no significant difference. Furthermore, the Hurst coefficients of the average power spectrum density were similar for all biofilms. Fractal parameters confirmed that higher concentrations of fruit extract induced a superior topographic irregularity. However, fractal lacunarity does not show any significant difference confirming the similarity of the microtextures. Moreover, fractal succolarity and surface entropy exhibited values that suggested ideal percolation and strong topographic uniformity, respectively, indicating that these films can uniformly adhere to other surfaces. Our results confirm that the stereometric and fractal parameters can be relevant for the surface characterization of microbial films, which can be of great importance to the biomedical field.

Structural evaluation of polymeric microbial films grown on kefir loaded with Maytenus rigida extract

Kefir is a probiotic that has several health promising properties. Its grains can form microbial films on different types of substrates. In the present work, the surface characteristics of kefir biofilms associated with Maytenus rigida Mart. extract were minutely studied. Three different concentrations of plant extract were included in the biofilm forming solutions, where fresh grains of kefir were inoculated. The results showed that the plant extract was successfully incorporated into the exopolysaccharide matrix of the biofilm. The main chemical components found linked to the plant extract were triterpenes. The crystallinity of biofilms increased with the addition of the plant extract. The morphology revealed that at low concentrations of the extract there was a prevalence of lactobacilli, while at high concentrations yeasts were more observed. Adhesion and wettability were higher for biofilm with less extract. These results revealed that a combination of plant extract and kefir's exopolysaccharide could form biofilms with chemical and topographic properties of great interest in regenerative medicine.

Advanced micromorphology study of microbial films grown on Kefir loaded with Açaí extract

In this work, an advanced analysis of the 3D surface microtexture of the microbial films grown on Kefir loaded with Açaí extract was performed. Atomic force microscopy was used to characterize the 3D surface microtexture data in correlation with the stereometric analyses to allow a better understanding of the surface micromorphology consistent with ISO 25178-2: 2012. Two new parameters, fractal succolarity and fractal lacunarity, have been inserted for a quantitative approach to microtexture. The results revealed that the morphology was affected by the increase of the Açaí concentration in biofilms, as well as the fractal succolarity and lacunarity. Adhesive bacteria of the genus Lactobacillus were observed for the lowest concentrations of Açaí. Moreover, it was found that the surface of the biofilms has shown saturation when the concentration has changed from 4 to 6 % of Açaí. These results are of great interest in the characterization of surfaces with promising application like skin dressing.

Wet weather water quality modelling of a Portuguese urban catchment: difficulties and benefits

This paper discusses the use of water quality deterministic modelling together with an integrated approach to assess the impact of urban stormwater discharges into ephemeral watercourses, based on the study of a Portuguese catchment. The description of the main aspects, difficulties and benefits found during data collection and model calibration and verification is presented, and the associated uncertainties and errors discussed. Experimental results showed a strong short- and long-term impact of sewer discharges on rivers, and confirmed deposition, resuspension and transport of pollutants as important processes for the water quality. However, the resuspension of riverbed sediment pollutants during storms was probably more significant than the direct impact of the urban discharges. The HydroWorks model was used since it allows for the calculation of pollutant build-up on catchment surfaces and in gully pots, their wash-off, and the deposition and erosion of sediments in sewers. However, it uses several constants, which could not be independently calibrated, increasing the uncertainty already associated with the data. River flows have quite different magnitude from the sewer system overflows, which, together with the difficulties in evaluating river flow rates, makes the integrated modelling approach rather complex and costly.