Accuracy of Point Load Index and Brazilian Tensile Strength in Predicting the Uniaxial Compressive Strength of the Rocks: A Comparative Study.

Uniaxial compressive strength (UCS) of rocks is one of the main parameters required in the design of geotechnical projects such as tunnels, dams, or rock slopes. According to the literature, there are a large number of predictive regression equations to evaluate the UCS from the point load index (PLI) and Brazilian tensile strength (BTS). However, the equations developed in previous studies have different accuracies in UCS prediction. A more accurate prediction of the UCS will result in a more appropriate design of the geotechnical project, and thus ensure its success during operation. In the present paper, a comparative study was conducted between the accuracy of PLI and BTS in predicting the UCS of the limestone and sandstone. Moreover, the role of porosity (n) on the accuracy of predicting the UCS from PLI and BTS was investigated. Some statistical indices were used to investigating the accuracy of predictive regression equations of UCS. The results revealed that the UCS of rocks can be predicted with a higher accuracy using BTS compared with PLI. Also, the findings showed that the n had a significant role in increasing the accuracy of PLI- and BTS-based regression equations of the UCS predictive. The predictive equations established in the present study can be used in practical applications for indirect evaluation of limestone and sandstone UCS in the site of a geotechnical project.

Molecular Characterization of Multidrug-Resistant Escherichia coli from Fecal Samples of Wild Animals.

Antimicrobial resistance (AMR) surveillance in fecal Escherichia coli isolates from wildlife is crucial for monitoring the spread of this microorganism in the environment and for developing effective AMR control strategies. Wildlife can act as carriers of AMR bacteria and spread them to other wildlife, domestic animals, and humans; thus, they have public health implications. A total of 128 Escherichia coli isolates were obtained from 66 of 217 fecal samples obtained from different wild animals using media without antibiotic supplementation. Antibiograms were performed for 17 antibiotics to determine the phenotypic resistance profile in these isolates. Extended-spectrum ß-lactamase (ESBL) production was tested using the double-disc synergy test, and 29 E. coli strains were selected for whole genome sequencing. In total, 22.1% of the wild animals tested carried multidrug-resistant E. coli isolates, and 0.93% (2/217) of these wild animals carried E. coli isolates with ESBL-encoding genes (blaCTX-M-65, blaCTX-M-55, and blaEC-1982). The E. coli isolates showed the highest resistance rates to ampicillin and were fully susceptible to amikacin, meropenem, ertapenem, and imipenem. Multiple resistance and virulence genes were detected, as well as different plasmids. The relatively high frequency of multidrug-resistant E. coli isolates in wildlife, with some of them being ESBL producers, raises some concern regarding the potential transmission of antibiotic-resistant bacteria among these animals. Gaining insights into antibiotic resistance patterns in wildlife can be vital in shaping conservation initiatives and developing effective strategies for responsible antibiotic use.

Effectiveness of historical smallpox vaccination against mpox clade II in men in Denmark, France, the Netherlands and Spain, 2022.

BackgroundIn 2022, a global monkeypox virus (MPXV) clade II epidemic occurred mainly among men who have sex with men. Until early 1980s, European smallpox vaccination programmes were part of worldwide smallpox eradication efforts. Having received smallpox vaccine > 20 years ago may provide some cross-protection against MPXV.AimTo assess the effectiveness of historical smallpox vaccination against laboratory-confirmed mpox in 2022 in Europe.MethodsEuropean countries with sufficient data on case vaccination status and historical smallpox vaccination coverage were included. We selected mpox cases born in these countries during the height of the national smallpox vaccination campaigns (latest 1971), male, with date of onset before 1 August 2022. We estimated vaccine effectiveness (VE) and corresponding 95% CI for each country using logistic regression as per the Farrington screening method. We calculated a pooled estimate using a random effects model.ResultsIn Denmark, France, the Netherlands and Spain, historical smallpox vaccination coverage was high (80-90%) until the end of the 1960s. VE estimates varied widely (40-80%, I2 = 82%), possibly reflecting different booster strategies. The pooled VE estimate was 70% (95% CI: 23-89%).ConclusionOur findings suggest residual cross-protection by historical smallpox vaccination against mpox caused by MPXV clade II in men with high uncertainty and heterogeneity. Individuals at high-risk of exposure should be offered mpox vaccination, following national recommendations, regardless of prior smallpox vaccine history, until further evidence becomes available. There is an urgent need to conduct similar studies in sub-Saharan countries currently affected by the MPXV clade I outbreak.

Association between Falls, Fear of Falling and Depressive Symptoms in Community-Dwelling Older Adults.

BACKGROUND: Longevity increases pose public health challenges, especially in managing falls and their psychological impacts on older adults. Limited evidence exists on the relationship between a fear of falling (FOF), previous falls, and depressive symptoms among community-dwelling older adults. OBJECTIVE: To evaluate the association between falls, FOF, and depressive symptoms in community-dwelling older adults. METHODS: This cross-sectional study, conducted in 2018, included 400 older adults from a Basic Health Unit in São Paulo, Brazil. The Geriatric Depression Scale (GDS-15) and the International Falls Efficacy Scale (FES-I) were used, along with self-report questionnaires on fall history. Linear and logistic regression were used to analyze the relationships between variables. RESULTS: The mean age was 75.2 (SD = 8.53) years, with 63.2% being female. Depressive symptoms were observed in 18.3% of the participants, while 90.5% reported a fear of falling (FOF). More than half (63.0%) experienced falls, with 49.5% occurring in the last year. Factors such as the female gender, negative health perceptions, and functional dependence were associated with depressive symptoms. Adjusted analyses indicated that both a fear of falling (FOF) (B = 0.043; p = 0.012) and a history of falls (B = 0.725; p = 0.015) were associated with depressive symptoms. CONCLUSIONS: Falls, FOF, and depressive symptoms are interlinked among older adults, underscoring the need for targeted interventions to improve their mental and physical health.

Effectiveness of permanent drift fences in reducing roadkill risk of amphibians.

Roads are an important source of human economic progress, but also a threat to wildlife populations and natural habitats. Roads are responsible for the direct mortality of hundreds of millions of animals worldwide, with special negative effects for amphibians. Since the middle of the twentieth century, various types of mitigation measures have been constructed to reduce the negative effects of roads. However, despite the large availability of potential solutions designed for this purpose, there is still a knowledge gap about their effectiveness for amphibians. This study analysed whether permanent concrete drift fences reduced the roadkill risk for amphibians. We applied a before-after-control-impact (BACI) design in two road segments with concrete drift fences for amphibians. We recorded amphibians on these road segments three years before and three years after the fence installation. We further tested whether the presence of these mitigation measures transferred the animals to sites adjacent to the drift fences, creating new potential mortality aggregation sites (fence-end effect). Our results show a significant reduction in the number of amphibians reaching the sites with the drift fences. We were, however, unable to demonstrate the potential movement route transference, as our results were inconclusive. Despite the increase in amphibian numbers at the control sites in the first year after fence installation, the following two years presented similar amphibian numbers as the pre-fence years. We recognise the importance of permanent drift fences in reducing the mortality of amphibian populations; however, we encourage future studies to include tunnel-crossing data as well, to truly unveil the roadkill reduction power of amphibian mitigation measures, while maintaining or increasing connectivity between roadside habitats.

Quantification of amino acids secreted by yeast cells by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

Monitoring the levels of amino acids (AAs) in biological cell cultures provides key information to understand the regulation of cell growth and metabolism. Saccharomyces cerevisiae can naturally excrete AAs, making accurate detection and determination of amino acid levels within the cultivation medium pivotal for gaining insights into this still poorly known process. Given that most AAs lack ultraviolet (UV) chromophores or fluorophores necessary for UV and fluorescence detection, derivatization is commonly utilized to enhance amino acid detectability via UV absorption. Unfortunately, this can lead to drawbacks such as derivative instability, labor intensiveness, and poor reproducibility. Hence, this study aimed to develop an accurate and stable hydrophilic interaction liquid chromatography-tandem mass spectrometry analytical method for the separation of all 20 AAs within a short 17-min run time. The method provides satisfactory linearity and sensitivity for all analytes. The method has been validated for intra- and inter-day precision, accuracy, recovery, matrix effect, and stability. It has been successfully applied to quantify 20 AAs in samples of yeast cultivation medium. This endeavor seeks to enhance our comprehension of amino acid profiles in the context of cell growth and metabolism within yeast cultivation media.

Physiological Adaptations to Progressive Endurance Exercise Training in Adult and Aged Rats: Insights from the Molecular Transducers of Physical Activity Consortium (MoTrPAC).

While regular physical activity is a cornerstone of health, wellness, and vitality, the impact of endurance exercise training on molecular signaling within and across tissues remains to be delineated. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to characterize molecular networks underlying the adaptive response to exercise. Here, we describe the endurance exercise training studies undertaken by the Preclinical Animal Sites Studies component of MoTrPAC, in which we sought to develop and implement a standardized endurance exercise protocol in a large cohort of rats. To this end, Adult (6-mo) and Aged (18-mo) female (n = 151) and male (n = 143) Fischer 344 rats were subjected to progressive treadmill training (5 d/wk, ∼70%-75% VO2max) for 1, 2, 4, or 8 wk; sedentary rats were studied as the control group. A total of 18 solid tissues, as well as blood, plasma, and feces, were collected to establish a publicly accessible biorepository and for extensive omics-based analyses by MoTrPAC. Treadmill training was highly effective, with robust improvements in skeletal muscle citrate synthase activity in as little as 1-2 wk and improvements in maximum run speed and maximal oxygen uptake by 4-8 wk. For body mass and composition, notable age- and sex-dependent responses were observed. This work in mature, treadmill-trained rats represents the most comprehensive and publicly accessible tissue biorepository, to date, and provides an unprecedented resource for studying temporal-, sex-, and age-specific responses to endurance exercise training in a preclinical rat model.

Determinants of Sporadic Shiga Toxin-Producing Escherichia coli (STEC) Infection in Denmark, 2018-2020: A Matched Case-Control Study.

Infections with Shiga toxin-producing Escherichia coli (STEC) are increasing in Denmark and elsewhere. STEC is also the most frequent cause of haemolytic uraemic syndrome (HUS) in Danish children. Most cases are considered sporadic, while approximately one-third can be attributed to a known source of infection. Hence, we examined sources of sporadic STEC infection in Denmark. From January 2018 to December 2020, we conducted a prospective nationwide case-control study among Danish adults and children. Cases with confirmed positive STEC infection were notified infections within the national laboratory surveillance system. Control persons were randomly selected from the Danish Civil Registration System, individually matched in age in 5-year bands and sex. Participants were invited by an electronic letter to complete either an adult or child questionnaire online. Univariate and adjusted matched odds ratios were computed for adults and children using conditional logistic regression. The study recruited 1583 STEC cases and 6228 controls. A total of 658 cases (42%) and 2155 controls (35%) were included in the analysis. Depending on age, univariate analysis adjusted for socio-demographic determinants showed that the consumption of boiled beef (mOR = 2.2, 95% confidence interval (CI): 1.6-3.1) and fried minced beef (mOR = 1.6, CI: 1.2-2.1), drinking raw (unpasteurized) milk (mOR = 11, CI 1.1-110), eating grilled food (mOR = 9.8, CI: 5.6-17) and having a household member using diapers (mOR = 2.1, CI: 1.4-3.2) were determinants of sporadic STEC infection. Further multivariate adjusted analysis resulted in the same determinants. This study confirms that beef is an overall important risk factor for STEC infection in Denmark. We also present evidence that a proportion of sporadic STEC infections in Denmark are determined by age-specific eating habits, environmental exposures and household structure, rather than being exclusively food-related. These findings are relevant for targeted public health actions and guidelines.

Programmes Addressed to Informal Caregivers' Needs: A Systematic Literature Review.

BACKGROUND: Addressing informal caregivers' needs is essential for ensuring quality healthcare and promoting citizen-centred care. This systematic review assessed current knowledge about programmes aimed at meeting the needs of informal caregivers of adults who are dependent on others for daily life activities. METHODS: Following the PRISMA guidelines, the electronic databases EBSCOhost Research Platform, MEDLINE, CINAHL, Scopus, Web of Science and The Virtual Health Library were searched for randomized experimental studies published between 2012 and 2022 that implemented programmes addressing informal caregivers' needs to improve their experiences, health, and well-being. Quality was assessed using the standardized critical evaluation tools from the Joanna Briggs Institute. Two independent investigators performed the eligibility assessment and data extraction. Quantitative data on the effectiveness of interventions were collected, and the content of each intervention was synthesized and aggregated into categories, through narrative synthesis. RESULTS: The majority of the included studies (n = 16) were conducted in European countries and implemented a structured intervention programme compared to the provision of usual care. The studies were of fair to high methodological quality, with a higher risk of bias related to blinding. The results supported the achievement of favourable health outcomes among informal caregivers, namely improvements in mental health (n = 3) and quality of life (n = 3) and a decrease in psychological symptomatology (n = 5) and burden (n = 3). None of the interventions reported adverse outcomes; however, five studies did not describe significant differences in the outcomes assessed after the implementation of the programmes. Interventions focusing on training and educating caregivers (n = 14) and cognitive-behavioural strategies (n = 7) were the most common, while programmes focusing on emotional and psychological support as a resource to improve caregivers' psychological outcomes were scarce. CONCLUSIONS: This systematic review adds to the growing body of evidence and insight showing that programmes that address informal caregivers' needs seem to contribute to better physical and psychological health outcomes through the promotion of caregivers' educational support and the implementation of cognitive-behavioural strategies. Future research should implement methodologically robust cross-country programmes tailored to informal caregivers' physical, emotional, psychosocial, societal, and educational needs throughout the care trajectory.

The Effect of Coping on the Relationship between Work-Family Conflict and Stress, Anxiety, and Depression.

The challenges experienced in the context of the pandemic have required a significant reconciliation between work and family domains due to confinement and the need to spend more time at home, which may have increased the levels of stress, anxiety, and depression, making it necessary to use resilient coping strategies to overcome the difficulties felt. This study examined the effect of resilient coping on the relationship between work-family conflict and stress, anxiety, and depression in this context. Data were collected using a self-report protocol from a sample of Portuguese workers (N = 476). The results indicated that work-family conflict was positively associated with stress, anxiety, and depression. Resilient coping established a negative relationship with stress, anxiety, and depression. The moderation effect was not corroborated; it was found that in the presence of the moderating variable (resilient coping), the relationship between the variables of work-family conflict and stress, anxiety, and depression was strengthened. This study reinforces the importance of appropriate interventions in resilient coping in the work-family context, which helps control stress, anxiety, and resilience levels.

Transitional care for older persons with need of geriatric rehabilitation nursing interventions.

BACKGROUND: The literature review notes that people in need of care from Rehabilitation Programs do not always see their continuity ensured. OBJECTIVE: This study aim to analyze the perspective of Specialists Nurse in Rehabilitation Nursing in relation to the organization and specialized intervention of transitional care for older people in need of rehabilitation programs. METHODS: This is a qualitative study within the interpretivist paradigm. A focus group with 8 nurses and 13 interviews with Portuguese nurses were carried out between April 2022 and February 2023. Content analysis was carried out. RESULTS: The triangulation of the data made it possible to identify 3 categories: Coordination of a transitional care program; Empowering the person to self-manage the transitional care process and Empowering the Informal Caregiver. CONCLUSIONS: It is imperative to promote the coordination of transitional care, increase the functional capacity of the person and empower the informal caregiver.

Empowering Cancer Patients with Self-Care and Pain Management Skills: A Quasi-Experimental Study.

BACKGROUND: Cancer patients experience distress as a result of their health condition, which, in turn, contributes to the progression of the disease. Moreover, their daily activities, well-being, and health status are significantly impacted by pain and other symptoms. In this context, empowering these patients with self-care and pain management skills can greatly contribute to effective symptom control. AIM: To develop and implement an educational approach focused on empowering family caregivers and patients with advanced cancer in effectively managing pain at home. METHOD: An educational program, PECP/C-Pain Management, was developed to empower family caregivers and cancer patients to manage pain at home. A quasi-experimental study involving 52 participants with advanced cancer was conducted to test the program. Participants' skills, behaviors, and knowledge related to self-care and pain management were assessed before and after the intervention using an appropriate instrument, the Pain Management Knowledge and Behavior Scale. RESULTS: Pain was reported as the primary symptom, and following the educational program, participants were able to monitor pain and other symptoms and effectively self-manage their treatment. CONCLUSIONS: The findings suggest that the PECP/C-Pain Management intervention was effective in improving participants' knowledge and skills in managing pain, leading to better symptom control. In addition, the Pain Management Knowledge and Behavior Scale is a reliable tool for measuring the outcomes of this intervention.

Clinical and Epidemiological Assessment of Children and Adolescents Hospitalized with SARS-CoV-2 in the Pre-Amazon Region.

INTRODUCTION: SARS-CoV-2 infection usually presents similarly to other respiratory viral pathogens. Children and adolescents do not present as a group that is highly affected by the disease, having low infection rates. However, limited publications are associated with the findings of pneumonia in pediatric patients with COVID-19. OBJECTIVE: To analyze the clinical and epidemiological aspects of children and adolescents hospitalized with SARS-CoV-2 in a pre-Amazon region. METHODS: A retrospective study, carried out in four public hospitals in São Luís, Brazil where medical records of children and adolescents aged from 0 to 13 years, of both sexes, with clinical diagnosis of community-acquired pneumonia were evaluated from March 2020 to March 2021. RESULTS: Almost 40.0% of children were aged between 1 year and 5 years. Of the 128 children who had SARS-CoV-2, 3 are of indigenous ethnicity. Additionally, 78.6% of the children had fever and there was no significant difference between COVID-19 patients and those of other respiratory viruses. Eighteen patients had chronic neurological disease, which is the most common comorbidity observed in patients with coronavirus infection. Ground glass opacity attenuation was observed in 24.8% of children and adolescents with COVID-19. Anemia and increased inflammatory response markers were related to SARS-CoV-2 infection. More than 90.0% of patients admitted to hospital, regardless of etiology, were treated with antibiotics. Eighteen patients died. Pediatric multisystem inflammatory syndrome (PMIS) was diagnosed in 17 patients. CONCLUSIONS: SARS-CoV-2 in children and adolescents is mild, but the condition of patients with PMIS is more serious, with an increase in inflammatory biomarkers which can lead to death. Therefore, rapid diagnosis and differentiation of agents causing respiratory diseases are necessary for better therapeutic decision making, since the results of this study make us question the excessive use of antibiotics without meeting well-defined clinical-epidemiological criteria.

Strength Characteristics, Ultrasonic Wave Velocity, and the Correlation between Them in Clay Bricks under Dry and Saturated Conditions.

One of the methods used to discover the development of deterioration in bricks used as a construction material in a building is the monitoring of the bricks' strength characteristics over time. However, measuring the strength characteristics of bricks used in a building requires sampling for performing laboratory tests, which is not possible in some cases. As an alternative, ultrasonic wave velocity can be a useful, nondestructive tool for the indirect assessment of the strength characteristics of the bricks. In the present study, six different samples of clay bricks before utilization as construction materials in buildings located in Khorramabad City (Lorestan Province, western Iran) were collected. The mineralogical composition of the samples was studied using X-ray diffraction (XRD) analysis. As one common physical characteristic of the construction materials, the porosity (n) of the samples was measured. Next, the strength characteristics, including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and P-wave velocity (Vp), of the samples under dry and saturated conditions were determined. It was found that after the saturation of the samples, considerable decreases in the UCS and BTS and increases in the Vp occurred, respectively. By comparing the values of the UCS, BTS, and Vp of the samples under dry and saturated conditions, we found that the integrity loss for the UCS and BTS was higher than for the Vp. Results showed that the integrity loss of the UCS, BTS, and Vp was significantly affected by the n and clay mineral (CM) content of the samples. Considering the dry or saturated condition of the samples, there are good correlations with acceptable accuracy levels between the Vp and the UCS and BTS, with coefficients of determination (R2) varying from 0.95 to 0.98. Consequently, our findings showed that establishing UCS and BTS predictive equations for bricks before their use as a construction material can be a worthy, practical tool for monitoring the deterioration of bricks over time after their utilization in a building.

2,4,5-Triaminopyrimidines as blue fluorescent probes for cell viability monitoring: synthesis, photophysical properties, and microscopy applications.

Monitoring cell viability is critical in cell biology, pathology, and drug discovery. Most cell viability assays are cell-destructive, time-consuming, expensive, and/or hazardous. Herein, we present a series of newly synthesized 2,4,5-triaminopyrimidine derivatives able to discriminate between live and dead cells. To our knowledge, these compounds are the first fluorescent nucleobase analogues (FNAs) with cell viability monitoring potential. These new fluorescent molecules are synthesized using highly efficient and cost-effective methods and feature unprecedented photophysical properties (longer absorption and emission wavelengths, environment-sensitive emission, and unprecedented brightness within FNAs). Using a live-dead Saccharomyces cerevisiae cell and theoretical assays, the fluorescent 2,4,5-triaminopyrimidine derivatives were found to specifically accumulate inside dead cells by interacting with dsDNA grooves, thus paving the way for the emergence of novel and safe fluorescent cell viability markers emitting in the blue region. As the majority of commercially available viability dyes emit in the green to red region of the visible spectrum, these novel markers might be useful to meet the needs of blue markers for co-staining combinations.

Genome-wide association and functional genomic analyses for various hoof health traits in North American Holstein cattle.

Hoof diseases are a major welfare and economic issue in the global dairy cattle production industry, which can be minimized through improved management and breeding practices. Optimal genetic improvement of hoof health could benefit from a deep understanding of the genetic background and biological underpinning of indicators of hoof health. Therefore, the primary objectives of this study were to perform genome-wide association studies, using imputed high-density genetic markers data from North American Holstein cattle, for 8 hoof-related traits: digital dermatitis, sole ulcer, sole hemorrhage, white line lesion, heel horn erosion, interdigital dermatitis, interdigital hyperplasia, and toe ulcer, and a hoof health index. De-regressed estimated breeding values from 25,580 Holstein animals were used as pseudo-phenotypes for the association analyses. The genomic quality control, genotype phasing, and genotype imputation were performed using the PLINK (version 1.9), Eagle (version 2.4.1), and Minimac4 software, respectively. The functional genomic analyses were performed using the GALLO R package and the DAVID platform. We identified 22, 34, 14, 22, 28, 33, 24, 43, and 15 significant markers for digital dermatitis, heel horn erosion, interdigital dermatitis, interdigital hyperplasia, sole hemorrhage, sole ulcer, toe ulcer, white line lesion disease, and the hoof health index, respectively. The significant markers were located across all autosomes, except BTA10, BTA12, BTA20, BTA26, BTA27, and BTA28. Moreover, the genomic regions identified overlap with various previously reported quantitative trait loci for exterior, health, meat and carcass, milk, production, and reproduction traits. The enrichment analyses identified 44 significant gene ontology terms. These enriched genomic regions harbor various candidate genes previously associated with bone development, metabolism, and infectious and immunological diseases. These findings indicate that hoof health traits are highly polygenic and influenced by a wide range of biological processes.

The Perspective of Rehabilitation Nurses on Physical Exercise in the Rehabilitation of Older People in the Community: A Qualitative Study.

In the face of an increasingly aging population, nurses have to design and implement programs aimed at the elderly in order to keep them healthy and maintain their quality of life. Structured physical exercise and overall physical activity play a major role in maintaining an active lifestyle, improving health, preventing disease, and helping to maintain older people's quality of life. To investigate the importance of implementing physical exercise programs for the older person in the community, taking into account the perspective of the rehabilitation nurse specialist, this is a qualitative, exploratory, and descriptive study with nine rehabilitation nurses from various regions of Portugal who have experience of implementing physical exercise programs with the elderly. This study used semi-structured interviews, one of the most common data collection procedures in social and health research. Content analysis was used to analyze the data. The study received a positive opinion from the Ethics Committee. The participants' perspectives focused on the following subjects: "Physical exercise program for the elderly in the community", "Importance of physical exercise in the rehabilitation of the elderly in the community", "People's adherence to the programs", "Gains in health resulting from the implementation of these strategies" and "Gains from group activities". A set of indicators emerged from the analysis. Nurses recognize the importance of using structured physical exercise programs adjusted to the rehabilitation of the older person, with gains in promoting active and healthy aging.

Advances in Personalized Nursing Care.

Patient-centered care reflects the quality of personal, professional, and organizational relationships [...].

Effect of Salt Mist Ageing on the Physical and Mechanical Properties of Two Ignimbrites from the Canary Islands (Spain).

The aim of this research work is to study the effect of salt mist ageing on the physico-mechanical properties of two ignimbrites from the Canary Islands (Spain). Due to their insular nature and extensive coastlines, these regions are highly susceptible to atmospheric salt aerosols, which is a significant weathering agent for building materials. The ignimbrites analysed are marketed under the names "Azul Lomo Tomás de León" and "Marrón de Abades" and are widely used as building stones. Petrographic, mineralogical and chemical properties were obtained via polarisation microscopy, X-ray diffraction and X-ray fluorescence. The samples were subjected to 60 cycles of a salt mist environment, following relevant European standards. Scanning electron microscopy images of the specimens were analysed along with physical properties, including apparent density, open porosity, water absorption, colourimetry and ultrasound propagation velocity, initially and after every 20 cycles, allowing us to assess their evolution during the ageing test. Mechanical properties were evaluated using uniaxial compressive strength and flexural strength under concentrated load tests on two groups of specimens: one unaged and the other subjected to 60 ageing cycles. With the exception of apparent density, the other properties show a decrease between 5% and 30%. However, open porosity increases and is one of the properties most affected by the ageing test.

Guidelines for Natural Stone Products in Connection with European Standards.

The selection of ornamental stones for specific applications requires technical guidance since it should be based on the durability, service life, and aesthetic value of the stones. In most cases, these fundamentals provide quantitative data on the usability and performance of ornamental stones. The present study attempts to put forward a quantitative classification system for natural stone products concerning critical rock properties. For this purpose, fundamental physical and mechanical rock properties are listed based on European standards. Then, minimum limit values are proposed for different applications of natural stone products based on retrospective analyses of numerous ornamental stone applications. The suggested limit values based on several physical and mechanical rock properties can guide relevant engineers to initially consider possible rock types for use as natural stones in a wide range of applications. In this context, it is believed that the present study contributes to the natural stone industry by discussing the minimum limit values for the consideration of a wide range of rock types possibly usable in the dimension stone industry.