An Integrated Framework for Image Acquisition, Processing, and Analysis Procedures for Automated Damage Evaluation of Concrete Surfaces.

Concrete surface cracks serve as early indicators of potential structural threats. Visual inspection, a commonly used and versatile concrete condition assessment technique, is employed to assess concrete degradation by observing signs of damage on the surface level. However, the method tends to be qualitative and needs to be more comprehensive in providing accurate information regarding the extent of damage and its evolution, notwithstanding its time-consuming and environment-sensitive nature. As such, the integration of image analysis techniques with artificial intelligence (AI) has been increasingly proven efficient as a tool to capture damage signs on concrete surfaces. However, to improve the performance of automated crack detection, it is imperative to intensively train a machine learning model, and questions remain regarding the required image quality and image collection methodology needed to ensure the model's accuracy and reliability in damage quantitative analysis. This study aims to establish a procedure for image acquisition and processing through the application of an image-based measurement approach to explore the capabilities of concrete surface damage diagnosis. Digitizing crack intensity measurements were found to be feasible; however, larger datasets are required. Due to the anisotropic behavior of the damage, the model's ability to capture crack directionality was developed, presenting no statistically significant differences between the observed and predicted values used in this study with correlation coefficients of 0.79 and 0.82.

The Impact of Distinct Superplasticizers on the Degradation of Concrete Affected by Alkali-Silica Reaction (ASR).

The effect of two superplasticizers (SPs) with various equivalent (eq.) alkali contents (i.e., with 0.00009% and 4.1% of Na2Oeq, respectively) on the development of an alkali-silica reaction (ASR) was investigated through the use of multilevel assessment. This testing protocol showed promising results for evaluating concrete damage due to ASRs based on mechanical and microscopical testing protocols, specifically the stiffness damage test (SDT) and the damage rating index (DRI). Concrete specimens that incorporated the aforementioned SPs and distinct reactive aggregates (coarse and fine) were manufactured and then stored in conditions that enabled ASR development and were monitored over time. Upon reaching the desired expansion levels of this study, the concrete specimens were prepared for the multilevel assessment. The results show that the SP-incorporated concrete specimens with lower and higher alkali content yielded lower and higher deterioration results, respectively. This clearly confirms that while SP-incorporated concrete that contains SPs with a higher alkali content could increase the risk of ASR deterioration, those SPs with a very low amount of alkali content could act as a mitigation strategy against ASRs. Finally, an investigation into the influence of distinct SPs on the chemical composition of an ASR gel was conducted, which confirmed that the SP with a higher alkali content had the highest potential for further deterioration.

Alkali-Silica Reactions: Literature Review on the Influence of Moisture and Temperature and the Knowledge Gap.

The alkali-silica reaction is a universally known destructive mechanism in concrete that can lead to the premature loss of serviceability in affected structures. Quite an enormous number of research studies have been carried out focusing on the mechanisms involved as well as the mitigation and prevention of the reaction. A few in-depth discussions on the role of moisture and temperature exist in the literature. Nevertheless, moisture and temperature have been confirmed to play a vital role in the reaction. However, critical assessments of their influence on ASR-induced damage are limited. The available moisture in concrete needed to initiate and sustain the reaction has been predominantly quantified with the relative humidity as a result of difficulties in the use of other media, like the degree of capillary saturation, which is more scientific. This paper discussed the current state of understanding of moisture measurement in concrete, the role of moisture and temperature in the kinetics of the reaction, as well as the moisture threshold needed for the reaction. Furthermore, the influence of these exposure conditions on the internal damage caused by ASR-induced deterioration was discussed.

Damage Generated and Propagated by the AAR Reactive Aggregate from Kingston, Ontario, Canada.

It remains unclear in the literature what the cause of the so-called alkali-carbonate reaction (ACR) damage to concrete is. However, expansion and cracks as distress features are often attributed to the alkali-silica reaction (ASR). Therefore, this work aims to assess the damage to concrete generated and propagated by the so-called ACR-susceptible reactive aggregate through mechanical testing (i.e., the direct shear test), microscopy (the damage rating index-DRI), and other techniques. Distinct induced expansion levels (i.e., 0%, 0.05%, 0.12%, and 0.20%) were selected to compare the distress caused by ACR to concrete affected by ASR. The results show that the behavior of ACR, namely, as captured through the DRI, is inconsistent with that of ASR, thus attesting to ACR being a distinct distress mechanism. The damage captured through mechanical testing does not distinguish ACR from ASR; however, microscopy reveals that cracks in the cement paste are the main damage mechanism. The proportions of cracks in the cement paste are 40-50% of the total number of cracks, whereas open cracks in the aggregates normally characterizing ASR represent only up to 20% of the total cracks.

Assessing and Forecasting ISR-Affected Critical Infrastructure: State-of-the-Art and Challenges.

Internal swelling reactions (ISRs) are among the most critical deterioration mechanisms affecting infrastructure's durability worldwide. While preventative measures for new structures have been extensively explored, effective protocols for diagnosing and prognosing ISR-affected structures, especially at their early stages, are still required. Therefore, through a comprehensive bibliometric analysis, this study focuses on exploring the evolution and current methods for assessing and forecasting ISR damage in concrete structures. For diagnosis, a shift from concrete petrography and non-destructive techniques (NDTs) towards more comprehensive methods (i.e., multi-level assessment) with the stiffness damage test (SDT) and damage rating index (DRI) is observed. Moreover, it identifies the valuable inputs from residual expansion and pore solution analysis as relevant parameters for prognosis. Based on these findings, a structured management framework is proposed aiming to refine the diagnosis and prognosis processes of ISR-affected infrastructure, ultimately contributing to improved long-term structural health and maintenance strategies.

Cold-adapted strains as plant growth-promoting bacteria on soybean seeds and biocontrol agents against Macrophomina phaseolina.

AIM: The aim was to characterize cold-adapted bacteria by testing their PGP features and antagonistic activity against Macrophomina phaseolina, both in vitro and coating soybean seeds (Glycine max [L.] Merr.). METHODS AND RESULTS: Burkholderia gladioli MB39, Serratia proteamaculans 136 and Serratia proteamaculans 137 were evaluated. In vitro tests showed that S. proteamaculans 136 and 137 produce siderophore and indole-acetic acid (IAA), solubilize phosphate and fix nitrogen. Additionally, B. gladioli MB39 and S. proteamaculans 137 showed hydrolase activity and potent antifungal effects. The biocontrol efficacy over soybean seeds was evaluated using in vitro and greenhouse methods by immersing seeds into each bacterial suspension. As a result, S. proteamaculans 136 has improved the performance in all the seed germination evaluated parameters. In addition, S. proteamaculans 137 and B. gladioli MB39 strongly inhibited M. phaseolina, reducing the infection index values to 10% and 0%, respectively. CONCLUSION: Serratia proteamaculans 136, 137 and Burkholderia gladioli MB39 showed plant growth promotion features and inhibition of Macrophomina phaseolina infection by producing different antifungal compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results reinforce the application of cold-adapted Serratia proteamaculans and Burkholderia gladioli bacterial strains as candidates for developing microbial formulation to promote plant growth and guarantee antifungal protection in soybean crops.

Freezing and Thawing Resistance of Fine Recycled Concrete Aggregate (FRCA) Mixtures Designed with Distinct Techniques.

The pressure to use sustainable materials and adopt practices reducing the carbon footprint of the construction industry has risen. Such materials include recycled concrete aggregates (RCA) made from waste concrete. However, concrete made with RCA often presents poor fresh and hardened properties along with a decrease in its durability performance, especially when using its fine fraction (i.e., FRCA). Most studies involving FRCA use direct replacement methods (DRM) to proportion concrete although other techniques are available such as the Equivalent Volume (EV) and Particle Packing Models (PPMs); yet their impact on the durability performance, especially its performance against freezing and thawing (F/T), remains unknown. This work, therefore, appraises the F/T resistance of FRCA mixtures proportioned through various mix proportioning techniques (i.e., DRM, EV and PPMs), produced with distinct crushing processes (i.e., crusher's fines vs. finely ground). The results show that the mix design technique has a significant influence on the FRCA mixture's F/T resistance where PPM-proportioned mixtures demonstrate the best overall performance, exceeding the specified requirements while DRM-proportioned mixtures failed F/T resistance requirements. Moreover, the crushing process plays an important role in the recycled mixtures' cracking behavior under F/T cycles, where less processing leads to fewer cracks while remaining the most sustainable option overall.

Influence of the Mix Proportion and Aggregate Features on the Performance of Eco-Efficient Fine Recycled Concrete Aggregate Mixtures.

Most of the previous research on recycled concrete aggregates (RCA) has focused on coarse RCA (CRCA), while much less has been accomplished on the use of fine RCA particles (FRCA). Furthermore, most RCA research disregards its unique microstructure, and thus the inferior performance of concrete incorporating RCA is often reported in the fresh and hardened states. To improve the overall behaviour of RCA concrete advanced mix design techniques such as equivalent volume (EV) or particle packing models (PPMs) may be used. However, the efficiency of these procedures to proportion eco-efficient FRCA concrete still requires further investigation. This work evaluates the overall fresh (i.e., slump and rheological characterization) and hardened states (i.e., non-destructive tests, compressive strength and microscopy) performance of sustainable FRCA mixtures proportioned through distinct techniques (i.e., direct replacement, EV and PPMs) and incorporating different types of aggregates (i.e., natural and manufactured sand) and manufacturing processes (i.e., crusher fines and fully ground). Results demonstrate that the aggregate type and crushing process may influence the FRCA particles' features. Yet, the use of advanced mix design techniques, particularly PPMs, may provide FRCA mixes with quite suitable performance in the fresh (i.e., 49% lower yield stress) and hardened states (i.e., 53% higher compressive strength) along with a low carbon footprint.

Burkholderia gladioli MB39 an Antarctic Strain as a Biocontrol Agent.

Bioprospecting sub-explored environments such as Antarctic locations leads to finding out diverse activities, reducing harmful chemical usage that affects both human health and the environment. In this study, ~ 7000 cold-adapted bacterial strains were isolated from samples around Melchior Antarctic Base at 5 °C and more than 13,000 at 15 °C. Out of them, 900 different colony morphotypes were evaluated for antimicrobial production, and 13 isolates demonstrated antibacterial and antifungal activities. One isolate, closely related to Burkholderia gladioli according to 16S rDNA (99.8%), gyrB (99.6%) and Cpn60 (99.4%) gene sequence analysis, showed a consistent, broad antimicrobial spectrum against both pathogenic and phytopathogenic bacteria. Its potent antifungal activity inhibits the growth of various plant pathogenic fungi, whereas it was mainly studied against Penicillium digitatum and Macrophomina phaseolina, the causal agents of blue mould in postharvest fruits and charcoal rot in soybean crops, respectively. The antibacterial compound exhibited low molecular weight (< 6000 Da), resistance to lytic enzymes and stability in a broad range of temperature and pHs. Observations of the B. gladioli MB39 antifungal effects over M. phaseolina mycelia by scanning electron microscopy showed alterations in hyphal structures, reduced hyphal extension, and severe cell morphology changes such as cytoplasmic leakage, flattened and empty mycelia. Here we report the isolation and identification of a cold-adapted B. gladioli strain. The results describe the effectiveness of the antarctic strain for bacterial and fungal phytopathogens biocontrol and its potential for crop protection plans.

Effectiveness of the Zea mays-Streptomyces association for the phytoremediation of petroleum hydrocarbons impacted soils.

Restoring polluted sites by petroleum hydrocarbons is a challenge because of their complexity and persistence in the environment. The main objective of the present study was to investigate the performance of plant-actinobacteria system for the remediation of crude petroleum and pure-polycyclic aromatic hydrocarbons (PAHs) contaminated soils. The endophytic strain Streptomyces sp. Hlh1 was tested for its ability to degrade model PAHs (phenanthrene, pyrene and anthracene) in liquid minimal medium. Streptomyces sp. Hlh1 demonstrated the ability to grow on PAHs as sole carbon and energy source, reaching hydrocarbons removal of 63%, 93% and 83% for phenanthrene, pyrene and anthracene, respectively. Maize plant was chosen to study the impact of Streptomyces sp. Hlh1 inoculation on the dissipation of contaminants and plant growth. Thus, maize seedlings grown in soils contaminated with crude petroleum and pure-PAHs were inoculated with Streptomyces sp. Hlh1. Results showed that the endophyte inoculation increased contaminants removal. Maximum hydrocarbons removal (70%) was achieved in inoculated and planted soil contaminated with crude oil, while 61%, 59%, and 46% of hydrocarbons dissipation were registered for phenanthrene, pyrene and anthracene, respectively. These degradations rates were significantly higher compared to non-inoculated systems in all the treatments evaluated. Further, it was revealed that hydrocarbons (C8-C30) were efficiently degraded in plant-Streptomyces Hlh1 system. Moreover, the inoculation with the actinobacteria resulted significant plant development and enhanced photosynthetic pigments compared to plants grown in the other experimental conditions. The present study provide evidence that the inoculation of maize plants with Streptomyces sp. Hlh1 play a remarkable role in the removal of petroleum hydrocarbons, enhancing plant development in contaminated soils.

Pseudomonas yamanorum sp. nov., a psychrotolerant bacterium isolated from a subantarctic environment.

A psychrotolerant strain, 8H1(T), was isolated from soil samples collected in Isla de los Estados, Ushuaia, Argentina. Cells were Gram-negative, aerobic, straight rods, occurring singly or in pairs, non-spore-forming and motile by means of two polar flagella. The isolate was able to grow in the range 4-35 °C, with optimum growth at 28 °C. The predominant cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The polar lipid pattern of strain 8H1(T) comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid. Ubiquinone 9 (Q-9) was the predominant lipoquinone. The DNA G+C content was 59.8 mol%. 16S rRNA gene sequence-based phylogeny suggested the affiliation of strain 8H1(T) to the 'Pseudomonas fluorescens group', displaying ≥98.5 % sequence similarity to 29 type strains. A multilocus sequence analysis (MLSA) study performed by concatenating 16S rRNA, gyrB, rpoD and rpoB gene sequences showed that isolate 8H1(T) could be discriminated from closely related species of the genus Pseudomonas and placed in the 'Pseudomonas gessardii subgroup', including the species with the highest MLSA sequence similarities: Pseudomonas brenneri (96.2 %), P. gessardii (96.1 %), P. proteolytica (96.0 %), P. meridiana (96.0 %) and P. mucidolens (95.4 %). DNA-DNA hybridization analysis between 8H1(T) and the type strains of these closely related species revealed relatedness values of 27.0, 8.8, 41.2, 39.7 and 46.1 %, respectively. These results, together with differences in several phenotypic features, support the classification of a novel species, for which the name Pseudomonas yamanorum sp. nov. is proposed. The type strain is 8H1(T) ( = DSM 26522(T) = CCUG 63249(T) = LMG 27247(T)).

Isolation of Sphaerotilus-Leptothrix strains from iron bacteria communities in Tierra del Fuego wetlands.

Sheath-forming iron- and manganese-depositing bacteria belonging to the Sphaerotilus-Leptothrix group (SLG) are widespread in natural and artificial water systems. Known requirements for their growth include the presence of organic substrates and molecular oxygen. High concentrations of reduced iron or manganese, although not necessary for most species, make their growth a noticeable phenomenon. Such microbial communities have been studied mostly in the Northern Hemisphere. Here, we present descriptions of diverse ochre-depositing microbial communities in Tierra del Fuego, Argentina, using a combined approach of microscopical examination, clone library construction and cultivation focused on SLG bacteria. To date, only few SLG type strains are available. The present work increases the number and diversity of cultivated SLG bacteria by obtaining isolates from biofilms and sediment samples of wetlands in Tierra del Fuego. Thirty isolates were selected based on morphological features such as sheath formation and iron/manganese deposition. Five operational taxonomic units (OTUs) were deduced. Sequencing of 16S rRNA genes showed that one OTU is identical to the Leptothrix mobilis Feox-1(T) -sequence while the four remaining OTUs show similarity values related to previously described type strains. Similarity values ranged from 96.5% to 98.8%, indicating possible new species and subspecies.

Gluconic acid produced by Gluconacetobacter diazotrophicus Pal5 possesses antimicrobial properties.

Gluconic acid is produced in large quantities by the endophytic and diazotrophic bacterium Gluconacetobacter diazotrophicus Pal5. This organic acid derives from direct oxidation of glucose by a pyrroloquinoline-quinone-linked glucose dehydrogenase in this plant growth-promoting bacterium. In the present article, evidence is presented showing that gluconic acid is also responsible for the antimicrobial activity of G. diazotrophicus Pal5. The broad antagonistic spectrum includes Gram-positive and -negative bacteria. Eukaryotic microorganisms are more resistant to growth inhibition by this acid. Inhibition by gluconic acid can be modified through the presence of other organic acids. In contrast to other microorganisms, the Quorum Sensing system of G. diazotrophicus Pal5, a regulatory mechanism that plays a key role in several microbe-microbe interactions, is not related to gluconic acid production and the concomitant antagonistic activity.

Andrimid production at low temperature by a psychrotolerant Serratia proteamaculans strain.

Andrimid, a known non-ribosomal pseudo-peptide antibiotic, was isolated from a psychrotolerant Serratia proteamaculans strain. The antibiotic peptide was produced at low temperature (8 °C) in a 7.5 l BIOFLO 101 bioreactor under batch culture mode. Andrimid activity from S. proteamaculans culture was only detected at 25 °C and below and potent antibacterial activity was revealed against both, pathogenic and non-pathogenic bacteria. Minimal inhibitory concentration values determined by microdilution experiments varied in the range between 0.01 and 0.78 µg/ml. Antimicrobial purification and structure elucidation were carried out by LC-MS/MS and ¹H/¹³C NMR approaches. The effects on the ultrastructure of sensitive Escherichia coli 35,218 cells were observed by transmission electron microscopy at different inhibition stages. This work demonstrated the significance of bioprospection from cold environments through the screening of microorganisms with ability to produce cold-active biomolecules of biotechnological interest. S. proteamaculans 136 was revealed as a novel microbial source for andrimid production at low temperatures, showing biotechnological potential to be applied in cryopreservation, food or cosmetic industries against pathogenic bacteria.

Lactic acid bacteria isolated from apples are able to catabolise arginine.

We investigated the potentiality of lactic acid bacteria (LAB) isolated from two apples variety to utilize arginine at different initial pH values. Apples surface contained average levels of bacteria ranging from log 2.49 ± 0.53 to log 3.73 ± 0.48 cfu/ml for Red Delicious and Golden Delicious varieties, respectively. Thirty-one strains able to develop in presence of arginine at low pH were phenotypically and genotipically identified as belonging to Lactobacillus, Pediococcus and Leuconostoc genera. In general, they did not produce ammonia from arginine when cultivated in basal medium with arginine (BMA) at pH 4.5 or 5.2. When this metabolite was quantified only six strains belonging to Leuconostoc dextranicum, Lactobacillus brevis and Lactobacillus plantarum species formed higher ammonia amounts in BMA as compared to control. This was correlated with arginine utilization and it was more pronounced at pH 4.5 than 5.2. Analysis of citrulline production confirmed the arginine utilization in these bacteria by the arginine deiminase (ADI) pathway. Maxima citrulline production was observed for Lactobacillus brevis M15 at the two pH values. In this strain ammonia was formed at higher rate than citrulline, which was detected in concentration lower than 1 mM. Thus, main LAB species found on apple surfaces with abilities to degrade arginine by the ADI pathway under different conditions were reported here at the first time. The results suggested that the ADI pathway in apples LAB might not be mainly relevant for their survival in the acid natural environmental, despite leading to the ammonia formation, which may contribute to the increase in pH, coping the acid stress.

Cold-adapted microorganisms as a source of new antimicrobials.

Thirty out of 8,000 different colony morphotypes isolated from soil samples of Isla de los Estados were selected based on their ability to produce antimicrobials. The significant influence of culture media and incubation temperature on antimicrobial production was proved, being LB medium and 8 degrees C the conditions of choice. Most of the psychrotolerant isolates were phylogenetically related to Serratia proteamaculans (96.4-97.9%) while the psychrophilic isolated 8H1 was closely related to Pseudomonas sp. (90-94% similarity). Produced antimicrobials showed a promising wide spectrum of activity both against gram-positive and gram-negative pathogenic bacteria. They were suspected to be microcin-like compounds (Mw <2,000 Da) and showed a marked tolerance to heat (1 h in boiling water bath) and pH-treatments (1-12). Antimicrobial compounds also showed to partially keep their activity even after overnight freezing at -20 and -80 degrees C and displayed a negative net charge at pH 8.0, a common feature of class II microcins.

El uso del levamisole en las enfermedades respiratorias erónicas / Use of levamisole for chronic respiratory diseases

Se realiza un estudio en 69 pacientes pediátricos con diferentes enfermedades respiratorias crónicas. De ellos, en 52 se utilizó como tratamiento el levamisole a una dosis de 2,5 ml/kg de peso corporal por dosis 2 veces por semana en ciclos de 2 meses de duración. El resto de los pacientes (17) se seleccionó como grupo control, y se les administró un placebo 2 veces a la semana durante 2 meses. Se observó una mejoría clínica altamente satisfactoria o satisfactoria en el 100% de los pacientes tratados con levamisole, mientras en 13 (76,6%) de los 17 pacientes del grupo control, no se observó ninguna mejoría. No se presentaron reacciones tóxicas o secundarias en ninguno de los pacientes tratados con levamisole. Se concluye que dicho medicamento fue efectivo en el tratamiento en un grupo de pacientes con diferentes enfermedades respiratorias crónicas, tales como enfermedad bronquial alérgica, bronquitis crónica, y neumonías recidivantes

El uso del levamisole en las enfermedades respiratorias erónicas / Use of levamisole for chronic respiratory diseases

Se realiza un estudio en 69 pacientes pediátricos con diferentes enfermedades respiratorias crónicas. De ellos, en 52 se utilizó como tratamiento el levamisole a una dosis de 2,5 ml/kg de peso corporal por dosis 2 veces por semana en ciclos de 2 meses de duración. El resto de los pacientes (17) se seleccionó como grupo control, y se les administró un placebo 2 veces a la semana durante 2 meses. Se observó una mejoría clínica altamente satisfactoria o satisfactoria en el 100

de los pacientes tratados con levamisole, mientras en 13 (76,6

) de los 17 pacientes del grupo control, no se observó ninguna mejoría. No se presentaron reacciones tóxicas o secundarias en ninguno de los pacientes tratados con levamisole. Se concluye que dicho medicamento fue efectivo en el tratamiento en un grupo de pacientes con diferentes enfermedades respiratorias crónicas, tales como enfermedad bronquial alérgica, bronquitis crónica, y neumonías recidivantes (AU)