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The development of biofilm by pure SRB culture on carbon steel, and its role on corrosion were investigated using microscopic, spectroscopic, electrochemical and surface characterization techniques. Tubercle biofilm and irregularly shaped pits were observed on steel surfaces in high-nutrient biotic solution. Owing to development of a protective FeS film in 72 h immersion, corrosion resistance improved. In nutrient-deficient medium, a greater bacterial density attached to the metal surface as the consequence of starved bacteria seeking energy sources from metal. However, electrochemical non-homogeneity developed at the locations of their attachment, that gradually grew over the entire surface. [ABSTRACT FROM AUTHOR]

Frost formation poses challenges in various sectors, impacting efficiency and safety. Active methods involve energy-consuming processes like heating, while passive approaches utilize protective coatings or hydrophobic surfaces to minimize frost aggregation. However, low thermal conductivity remains a concern. In previous research, lotus leaves inspired micro-meter-sized asperities were effective in controlling frost growth. Applying this concept to plastic, particularly low-cost PVC, raised challenges due to its low thermal conductivity. The study explores utilizing carbon black (CB) waste from hard coating processes to enhance PVC's thermal conductivity, forming a micro-plastic texture (MPT). The research investigates the influence of CB amount and AC voltage frequency on MPT features and thermal conductivity, aiming for a sustainable solution to address frost-related issues. Incorporating 0.9 vol.% CB into PVC solution under a 2 kV AC electric field (6 Hz) resulted in an extensively distributed MPT on the surface. This MPT, formed under the 6 Hz condition, exhibited no in-plane bias, making it an ideal surface for preventing frost formation. Adding CB to PVC within the range of 0 to 2.1 vol.% and applying a 2 kV, 6 Hz AC electric field led to independent MPT formation at concentrations between 0.4 to 1.2 vol.%. Conducting cooling tests in atmospheric and vacuum conditions, we found that MPT with 0.9 vol.% CB displayed a thermal conductivity of approximately 0.19 kW/mK in atmospheric conditions, similar to aluminum alloy. However, with 1.2 vol.% or more CB, it decreased to about 0.15 kW/mK. In vacuum conditions, MPT with 1.2 vol.% CB exhibited a higher thermal conductivity of 0.063 kW/mK compared to the 0.055 kW/mK observed in MPT with 0 vol.% CB.

The development of biofilm by pure SRB culture on carbon steel, and its role on corrosion were investigated using microscopic, spectroscopic, electrochemical and surface characterization techniques. Tubercle biofilm and irregularly shaped pits were observed on steel surfaces in high-nutrient biotic solution. Owing to development of a protective FeS film in 72 h immersion, corrosion resistance improved. In nutrient-deficient medium, a greater bacterial density attached to the metal surface as the consequence of starved bacteria seeking energy sources from metal. However, electrochemical non-homogeneity developed at the locations of their attachment, that gradually grew over the entire surface.

Oxalic acid (C2H2O4) and Calcium (Ca2+) react to form the salt Calcium oxalate (CaOx), which crystallises into a variety of topologically diverse crystals. CaOx crystals have been found in at least 215 plant groups, which corresponds to numerous species. Crystals can be found in vascular, epidermal, ground, and other tissues in addition to roots, stems, leaves, flowers, fruits, and seeds. They develop in crystal idioblasts, specialised cells, in their vacuoles. According to recent studies, CaOx crystals are in fact useful tools that are crucial, especially in stressful conditions. As plants lack an excretory system, the Ca component regulates the cytosolic concentration levels and immobilises excess amounts of this element. Oxalates operate as a dynamic carbon store and set off an alert during photosynthesis, which results in the production of CO2. The article aims to provide readers with a greater understanding of Portulacaria afra's CaOx crystals and the projected crystal disintegration that would liberate carbon and supply the photosynthetic cycles with it as defence against salinity and drought stress.

Heterogeneous nucleation of water vapor on particles to promote particulate abatement is widely used in the fields of industrial dust removal pretreatment technology. Water vapor competition is a very important phenomenon in the process of particles nucleation, but due to the limitations of experimental methods, this phenomenon is difficult to observe and rarely received attention. Therefore, in order to reveal the influence of water vapor competition on particles nucleation, a direct visualization method based on the Environmental Scanning Electron Microscope (ESEM) is proposed in this work to obtain the water vapor competition process during particles nucleation at a microscopic scale. Firstly the effect of particle's surface structure on water vapor competition in heterogeneous nucleation of water vapor on the particles is visualized by the ESEM. The results show that the embryo appears randomly at any edge of the smooth spherical particle because water vapor competition at each point on the particle's surface is equal. While the embryo always appears on the protuberance of the convex spherical particle since water vapor competition is strongest there. Then the influence of particle's surface energy on water vapor competition is also visualized. Water vapor preferentially nucleates on the particle with smaller contact angle, which means the higher the surface energy, the more conducive it is for water vapor competition to form embryos. Finally, the impact of particle's aggregation modes on water vapor competition is also visualized by the ESEM. The results show that when the vapor supersaturation is constant, water vapor only nucleates on the two-close and three-circled particles while particles nucleation on the single particle is never observed. This is due to the strong water vapor competition at the particle's junction, where the embryos will collide and coalesce to form an embryo larger than the critical size to activate particles nucleation. The results of this study will deepen the microscopic understanding of water vapor competition in the process of particles nucleation. [ABSTRACT FROM AUTHOR]

This study is part of a comprehensive investigation that was performed in regard to a case of alterations on a carbographic ribbon used in a typewriter that was found and seized by inner security operations of the Arma dei Carabinieri, Italy. Thirty‐six coded scripts possessing potentially and criminally liable content were present on the tape; however, only the 6th and 7th scripts exhibited alterations of an uncertain nature. The study included sampling that was performed under sterile conditions of a large surface area of carbographic ribbons. A protocol based on physico‐chemical, microbiological, and biomolecular tools was established. Preliminary results revealed the presence of fungal contamination that was primarily located on the inner surface of the 6th and 7th scripts on the black carbographic ribbon. One fungal strain was isolated and identified by universal ITS‐PCR primer and rDNA sequencing as Alternaria infectoria strain NIS4. Fungal growth was monitored for 3 weeks in the laboratory under different environmental conditions (temperature, open‐closed system, and substrate). The A. infectoria NIS4 strain exhibited the best growth at 28°C under a closed system with RH near saturation. We also noted that the fungal growth was abundant at 15°C. Moreover, this fungus (a potential human pathogen) possessed the ability to colonize the surface of the new carbographic ribbon even when using mineral medium; however, this only occurred in a closed system environment and not in open systems due to rapid desiccation. Under our experimental conditions, the A. infectoria NIS4 strain could degrade gelatin as an organic matter present in trace amounts that are often used as a binder in a carbographic ribbon emulsions. The results revealed that the isolated microorganism was the major biological candidate capable of altering the investigated carbographic ribbon; however, these alterations could only occur under favourable environmental conditions. Aims: Identify the cause of microbial alterations on a carbographic ribbon in a typewriter used in a hypogean Italian criminal house named "covo." Methods and Results: The isolation and identification of biodeteriogens (Alternaria infectoria NIS4) were performed using both culture‐dependent and‐independent methods, including ITS regions‐primed PCR and rDNA techniques. Environmental scanning electron microscopy (ESEM) and optical observations were also performed. Growth tests and biodeterioration simulation tests on carbographic ribbons at the lab scale were performed under different environmental conditions. The A. infectoria NIS4 strain exhibited biodeterioration activity on carbographic ribbons under environmental conditions that were extremely favourable for growth. A high ability to colonize carbographic ribbon surfaces with fast and abundant growth at both 15°C and 28°C under lab‐scale conditions at RH near saturation was observed. Conclusions: In this forensic case study, the ability of the isolated micromycetes A. infectoria NIS4 strain to colonize and induce alterations and degradation in a carbographic ribbon stored under indoor environmental conditions was examined. When favourable conditions change over time, the risk of microbial colonization and the damage produced by the fungal biodeterioration processes on the synthetic material objects has been confirmed. Significance and Impact of Study: The current study contributes to the knowledge of biodeterioration processes in carbographic ribbon and the responsible agents, and our study provides an example of how environmental microbiology can also aid in forensic studies. [ABSTRACT FROM AUTHOR]

Microscopic, electrochemical and surface characterization techniques were used to investigate the effects of iron reducing bacteria (IRB) biofilm on carbon steel corrosion for 72 and 168 h under batch conditions. The organic nutrient availability for the bacteria was varied to evaluate biofilms formed under nutritionally rich, as compared to nutritionally deficient, conditions. Focused ion beam-scanning electron microscopy (FIB-SEM) was used to investigate the effect of subsurface biofilm structures on the corrosion characteristics of carbon steel. Hydrated biofilms produced by IRB were observed under environmental scanning electron microscope (ESEM) with minimal surface preparation, and the elemental composition of the biofilms was investigated using energy dispersive spectroscopy (EDX). Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) was used to provide information on the organic and inorganic chemical makeup of the biofilms. Electrochemical techniques employed for assessing corrosion, by open circuit potential, linear polarization and potentiodynamic polarization tests indicated no significant difference in the corrosion resistance for carbon steel in IRB-inoculated, compared to the abiotic solutions of common Postgate C after 72 and 168 h. However, the steel was found to be more susceptible to corrosion when the yeast extract was removed from the biotic environment for the 168 h test. In the absence of yeast nutrient, it is postulated that IRB received energy by transforming the protective film of Fe3+ into more soluble Fe2+ products. [ABSTRACT FROM AUTHOR]

The clinker mineral tricalcium aluminate (C3A) determines largely the early hydration characteristics of Portland cement. Therefore, understanding the influence of the polymer on the hydration of C3A is contributed to clarify the mechanism of polymer on the early hydration of cement-based material. The hydration environment of C3A in Portland cement was simulated by using C3A mineral, gypsum ( C S ¯ · H 2 ) and calcium hydroxide (CH). The specimens, whose water cement ratio (mw/mc) was 0.4 and carboxylated styrene–butadiene (SB) copolymer cement ratio (mp/mc) was 0, 5, 10, 15 and 20%, were cured at 20 ℃/RH90% for 6 h, 12 h, 1 day, 3 days, 7 days and 28 days, respectively. The effect of SB copolymer on the system of C3A– C S ¯ · H 2 –CH was investigated by the combination of isothermal calorimetry, X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM). It was found that the SB copolymer retards C3A hydration and reduces the heat of hydration. The XRD results revealed that addition of SB copolymer inhibits the consumption of C3A, delays the conversion of ettringite (AFt) to calcium monosulfate aluminate hydrate (AFm), promotes the formation of hydrated calcium aluminate (C4AH13), and reduces the crystallinity of AFm. [ABSTRACT FROM AUTHOR]

Microscopic, electrochemical and surface characterization techniques were used to investigate the effects of iron reducing bacteria (IRB) biofilm on carbon steel corrosion for 72 and 168 h under batch conditions. The organic nutrient availability for the bacteria was varied to evaluate biofilms formed under nutritionally rich, as compared to nutritionally deficient, conditions. Focused ion beam-scanning electron microscopy (FIB-SEM) was used to investigate the effect of subsurface biofilm structures on the corrosion characteristics of carbon steel. Hydrated biofilms produced by IRB were observed under environmental scanning electron microscope (ESEM) with minimal surface preparation, and the elemental composition of the biofilms was investigated using energy dispersive spectroscopy (EDX). Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) was used to provide information on the organic and inorganic chemical makeup of the biofilms. Electrochemical techniques employed for assessing corrosion, by open circuit potential, linear polarization and potentiodynamic polarization tests indicated no significant difference in the corrosion resistance for carbon steel in IRB-inoculated, compared to the abiotic solutions of common Postgate C after 72 and 168 h. However, the steel was found to be more susceptible to corrosion when the yeast extract was removed from the biotic environment for the 168 h test. In the absence of yeast nutrient, it is postulated that IRB received energy by transforming the protective film of Fe3+ into more soluble Fe2+ products.

PREMISE: Biological invasions increasingly threaten native biodiversity and ecosystem services. One notable example is the common reed, Phragmites australis, which aggressively invades North American salt marshes. Elevated atmospheric CO2 and nitrogen pollution enhance its growth and facilitate invasion because P. australis responds more strongly to these enrichments than do native species. We investigated how modifications to stomatal features contribute to strong photosynthetic responses to CO2 and nitrogen enrichment in P. australis by evaluating stomatal shifts under experimental conditions and relating them to maximal stomatal conductance (gwmax) and photosynthetic rates. METHODS: Plants were grown in situ in open‐top chambers under ambient and elevated atmospheric CO2 (eCO2) and porewater nitrogen (Nenr) in a Chesapeake Bay tidal marsh. We measured light‐saturated carbon assimilation rates (Asat) and stomatal characteristics, from which we calculated gwmax and determined whether CO2 and Nenr altered the relationship between gwmax and Asat. RESULTS: eCO2 and Nenr enhanced both gwmax and Asat, but to differing degrees; gwmax was more strongly influenced by Nenr through increases in stomatal density while Asat was more strongly stimulated by eCO2. There was a positive relationship between gwmax and Asat that was not modified by eCO2 or Nenr, individually or in combination. CONCLUSIONS: Changes in stomatal features co‐occur with previously described responses of P. australis to eCO2 and Nenr. Complementary responses of stomatal length and density to these global change factors may facilitate greater stomatal conductance and carbon gain, contributing to the invasiveness of the introduced lineage. [ABSTRACT FROM AUTHOR]

Processes of water condensation and desublimation on solid surfaces are ubiquitous in nature and essential for various industrial applications, which are crucial for their performance. Despite their significance, these processes are not well understood due to the lack of methods that can provide insight at the nanolevel into the very first stages of phase transitions. Taking advantage of synchrotron grazing-incidence wide-angle X-ray scattering (GIWAXS) and environmental scanning electron microscopy (ESEM), two pathways of the frosting process from supersaturated vapors were studied in real time for substrates with different wettabilities ranging from highly hydrophilic to superhydrophobic. Within GIWAXS, a fully quantitative structural and orientational characterization of the undergoing phase transition reveals the information on degree of crystallinity of the new phase and determines the ordering at the surfaces and inside the films at the initial stages of water/ice nucleation from vapor onto the substrates. The diversity of frosting scenarios, including direct desublimation from the vapor and two-stage condensation-freezing processes, was observed by both GIWAXS and ESEM for different combinations of substrate wettability and vapor supersaturations. The classical nucleation theory straightforwardly predicts the pathway of the phase transition for hydrophobic and superhydrophobic substrates. The case of hydrophilic substrates is more intricate because the barriers in Gibbs free energy for nucleating both liquid and solid embryos are close to each other and comparable to thermal energy k B T . At that end, classical nucleation theory allows concluding a relation between contact angles for ice and water embryos on the basis of the observed frosting pathway.

Heterogeneous condensation of water vapor on particles is widely used in the fields of atmospheric cloud physics and industrial particulate abatement. Particles surface wettability plays a fundamental role in water vapor condensation, but a microscopic insight of the impact of particles surface wettability on vapor condensation is lacked. Therefore, the Environmental Scanning Electron Microscope (ESEM) is adopted to directly visualize vapor condensation on particles with different surface wettability at a microscopic scale. Firstly heterogeneous condensation of water vapor on the hydrophilic and hydrophobic particles is obtained by the ESEM. The results show that when water vapor condenses on the hydrophilic particles, a spherical cap-shaped embryo first appears and subsequently develops into a spherical droplet to finally wrap the single particle. While on the hydrophobic particles, a spherical cap-shaped embryo will first appear and continue to grow into a spherical droplet to finally detach from the particle. Then the wetting coefficient is introduced to characterize the wetting degree of the droplet on the particle. The wetting coefficient will increase with the decrease of the contact angle, so the wettability of water vapor on the hydrophilic particles is better than that on the hydrophobic particles. Meanwhile based on classical nucleation theory, the geometrical factor and the critical supersaturation will decrease when the contact angle decreases, making it easier for water vapor to condense on the hydrophilic particles. Finally the line tension is investigated to explain the condensation mechanism. On the hydrophilic particles, when the droplet has crossed the equatorial line of the particle, the positive line tension promotes the spreading movement of the droplet over the particle to form a wrapped spherical droplet. Therefore, there is a transition from a spherical cap-shaped embryo before crossing the equatorial line of the particle to a wrapped spherical droplet after crossing the equatorial line. While on the hydrophobic particles, the negative line tension suppresses the spreading movement of the droplet over the particle to form a detached spherical droplet. So there is a transition from a spherical cap-shaped embryo before crossing the equatorial line of the particle to a detached spherical droplet after crossing the equatorial line. • Heterogeneous condensation of water vapor on hydrophilic and hydrophobic particles is directly visualized. • A spherical cap-shaped embryo appears on the hydrophilic particle and develops into a spherical droplet to wrap the particle. • A spherical cap-shaped embryo appears on the hydrophobic particle and grows into a spherical droplet to detach from the particle. • The positive line tension promotes the spreading movement of the droplet over the hydrophilic particle. • The negative line tension suppresses the spreading movement of the droplet over the hydrophobic particle. [ABSTRACT FROM AUTHOR]

Results of positron annihilation lifetime spectroscopy (PALS) and microscopic studies on simple microorganisms, brewing yeasts, are presented. Lifetime of ortho-positronium (o-Ps) were found to change from 2.4 to 2.9 ns (longer-lived component) for lyophilized and aqueous yeasts, respectively. Also hygroscopicity of yeasts in time was examined, allowing to check how water – the main component of the cell – affects PALS parameters, thus lifetime of o-Ps were found to change from 1.2 to 1.4 ns (shorter-lived component) for the dried yeasts. The time sufficient to hydrate the cells was found below 10 hours. In the presence of liquid water, an indication of reorganization of yeast in the molecular scale was observed. Microscopic images of the lyophilized, dried, and wet yeasts with best possible resolution were obtained using inverted microscopy (IM) and environmental scanning electron microscopy (ESEM) methods. As a result, visible changes to the surface of the cell me mbrane were observed in ESEM images.

Diatomite, a rock formed by the accumulation of opaline diatom frustules, is a preferred rawmaterial for themanufacturing of filters. Its uniqueness relies on the high porosity and inertness of the frustules. The presence of carbonates in some diatomite ores hinders these properties. The purpose of this study was to identify the type of carbonates and their association with the ore in a diatomite deposit, and to assess the suitability of determining the quality of the ore using techniques with potential for in-pit implementation. For this, run-of-mine samples were analysed using environmental scanning electron microscopy (ESEM) and infrared spectroscopy. The ESEM images showed that carbonate is present as cement and laminae. The infrared data revealed that the carbonate minerals correspond to aragonite and calcite, and that their occurrence is linked to the total amount of carbonate in the sample. By using a portable spectral instrument that uses diffuse reflectance, it was possible to classify the spectra of the ore samples based on the carbonate content. These results indicate that infrared technology could be used on-site for determining the quality of the ore, thus providing relevant information to assist the optimisation of mining and beneficiation activities. [ABSTRACT FROM AUTHOR]

Treatment of wood with aqueous dispersions of silica that have been modified with aluminum oxychloride (AlOCl) can impart wood water repellence and increased resistance to fungal decay. This study is a comparative survey on the effects of treatment with modified and non-modified silica dispersions in terms of the combustion behavior of the Scots pine (Pinus sylvestris L.) to evaluate the fire risk of this wood utilized as a construction material. The thermogravimetric results showed that treatments with the silica dispersions did not change the pyrolysis temperature of wood polymers, i.e. there was no synergetic interaction between silica and cell wall polymers during pyrolysis. Cone calorimetry (CONE) indicated that the silica-treated wood required longer time for ignition than the untreated control, but wood chars were similar. Treatments with both silica dispersions led to considerable reduction in the heat release (HR) and smoke production, but the cationically modified silica was more efficient than the unmodified silica. These findings were interpreted that incorporation of modified silica did not substantially influence the pyrolysis of cell wall polymers because they have not penetrated the cell wall; they have rather reduced the fire risk via forming a barrier against oxygen access and a thermal protection shield. [ABSTRACT FROM AUTHOR]

Environmental scanning electron microscopy (ESEM) permits to analyze samples in their native-hydrated state, allowing a broad spectrum of biological applications. In this study, ESEM equipped with energy dispersive X-ray spectrometer (EDS) was used as a fast method to analyze tissue morphology and to investigate metal distribution in the Ni hyperaccumulator Noccaea caerulescens , an established model to study the adaptation of plants to metalliferous soils. The low vacuum and wet mode operative conditions required the proper choice of experimental parameters both for morphological and compositional characterization of plant tissues. The calibration strategy for semi-quantitative analysis involved the use of Ni fortified agar as standard and signal normalization respect to endogenous carbon, chosen as internal standard. The obtained results are in accordance with present literature, showing a preferential Ni distribution in the epidermal cells respect to near the stomata for leaves and in the cotyledon epidermidis respect to cotyledon parenchyma area for seeds. Thanks to the absence of any time consuming sample treatment steps, ESEM-EDS technique can be proposed as valid strategy for in vivo high-throughput analysis of plant tissues and for a rapid screening and identification of other hyperaccumulator plants in a selected contaminated area. [ABSTRACT FROM AUTHOR]

In latex products manufacturing, protein has always been a problem due to the prevalence of latex protein allergy. Thus deproteinisation has been introduced to eliminate or reduce rubber latex protein content. However, the investigation on particles size and arrangement of particles in the rubber latex state before and after deproteinisation process has not been thoroughly explored. In this study, the particles size, arrangement and morphology of the film formed from modified latexes were monitored using Environmental Scanning Electron Microscopy (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) for various latexes treated with either urea or sodium dodecyl sulphate and combination of both as deproteinisation agent. The size of latex particles changed after deproteinisation and the arrangement of particles when films are formed revealed interesting packing occurrence between the deproteinised latexes. These occurrences were shown to be associated to chemicals or surfactant used in the deproteinisation. The use of urea in combination with sodium dodecyl sulphate in the deproteinisation contributed to good latex particles packing during film formation attributed to the appearance of soft shell latex particles. Clearly, the latex particles and film morphologies is profoundly influenced by the type of deproteinisation agents used. [ABSTRACT FROM AUTHOR]

[Display omitted] Human respiratory mucus lining the airway epithelium forms a challenging barrier to inhalation therapeutics. Therefore, structural elucidation of hydrated mucus is essential for an efficient drug delivery development. The structure of mucus has been primarily investigated by conventional electron microscopy techniques, which operate under vacuum conditions and require sample preparation steps that might alter the structure of mucus. In this study we investigated the impact of dehydration on mucus and analyzed the structure of mucus in its hydrated state. Cryo-scanning electron microscopy (Cryo-SEM) analysis of mucus showed, that during the process of sublimation, non-porous structure of mucus is transformed into a porous network. Similarly, images acquired by environmental scanning electron microscopy (ESEM), revealed a non-porous structure of hydrated mucus, while further observation at decreasing pressure demonstrated the strong influence of dehydration on mucus structure. We could successfully visualize the structural organization of the major gel forming mucin MUC5B in its hydrated state by employing stimulated emission depletion (STED) microscopy, which allowed resolving the nano-scale patterns of mucin macromolecules within the essentially pore-free mucus structure. The general structural organization of mucus components was addressed by confocal laser scanning microscopy (CLSM), which revealed the heterogeneous and composite structure of mucus. These results provide a novel view on the native structure of mucus and will affect drug delivery development. [ABSTRACT FROM AUTHOR]