Prospective Relations between Life Stress, Emotional Clarity, and Suicidal Ideation in an Adolescent Clinical Sample.

OBJECTIVE: Although life stress has been linked to adolescent suicidal ideation, most past research has been cross-sectional, and potential processes characterizing this relation remain unclear. One possibility may be a lack of emotional clarity. Informed by stress generation, the current study examined prospective relations between episodic life stress, lack of emotional clarity, and suicidal ideation in an adolescent clinical sample. METHODS: The sample consisted of 180 youths (Mage = 14.89; SD = 1.35; 71.7% female; 78.9% White; 43.0% sexual minority) recruited from a psychiatric inpatient facility. Suicidal ideation severity was assessed at baseline and 18-month follow-up. Lack of emotional clarity and life stress were assessed at baseline, as well as 6-, and 12-month follow-ups. Two random-intercepts cross-lagged panel models were created to estimate within-person relations for variables of interest. RESULTS: At the within-person level, lack of emotional clarity at baseline predicted greater 6-month impact of interpersonal dependent stressors (b = 0.29, p = .012, 95% CI [0.07, 0.52]), which subsequently predicted a greater 12-month lack of emotional clarity (b = 0.41, p = .005, 95% CI [0.12, 0.70]). Next, a 12-month lack of emotional clarity but not interpersonal dependent stress, predicted greater 18-month suicidal ideation (b = 0.81, p = .006, 95% CI [0.23, 1.30]; R2 = .24, p < .001). No significant relations were found for the lack of emotional clarity and independent stress. CONCLUSIONS: Results support the stress generation hypothesis and suggest that future research should be conducted evaluating whether bolstering youth's understanding of their emotional experiences may reduce subsequent suicidal ideation.

Managing a Pregnancy in the Presence of the Rare Blood Group Antibody PP1Pk.

Pregnant women with p phenotype, who lack antigens P, P1, and Pk, spontaneously form anti-PP1Pk antibodies whose primary target is the placenta. The risk of miscarriage in these women is 50%-70% and reaches 87% in the second trimester. The therapies aim to reduce the titer of antibodies early in pregnancy. They also have risk of hemolytic transfusion reaction, with very few compatible red blood cell donors in the world. In this study, we present a case of successful pregnancy managed with autologous blood donations and plasmapheresis.

Biochemical characterization and gene structure analysis of the 24-kDa glutathione transferase sigma from Taenia solium.

Taenia solium can cause human taeniasis and/or cysticercosis. The latter can in some instances cause human neurocysticercosis which is considered a priority in disease-control strategies and the prevention of mental health problems. Glutathione transferases are crucial for the establishment and long-term survival of T. solium; therefore, we structurally analyzed the 24-kDa glutathione transferase gene (Ts24gst) of T. solium and biochemically characterized its product. The gene promoter showed potential binding sites for transcription factors and xenobiotic regulatory elements. The gene consists of a transcription start site, four exons split by three introns, and a polyadenylation site. The gene architecture is conserved in cestodes. Recombinant Ts24GST (rTs24GST) was active and dimeric. Anti-rTs24GST serum showed slight cross-reactivity with human sigma-class GST. A 3D model of Ts24GST enabled identification of putative residues involved in interactions of the G-site with GSH and of the H-site with CDNB and prostaglandin D2. Furthermore, rTs24GST showed optimal activity at 45 °C and pH 9, as well as high structural stability in a wide range of temperatures and pHs. These results contribute to the better understanding of this parasite and the efforts directed to fight taeniasis/cysticercosis.

Relations between discrimination, rejection sensitivity, negative affect, and decrements in problem-solving ability following social rejection: An experimental investigation.

INTRODUCTION: While negative affect and problem-solving deficits have been consistently linked to suicidal thoughts and behaviors, the latter are often conceptualized and studied as time- and/or context-invariant. Though requiring additional empirical support, theory suggests that discrimination may strengthen the relation between rejection sensitivity and increases in negative affect as well as declines in problem-solving abilities following rejection. The aim of the current study was to test this claim using a social rejection paradigm (i.e., Cyberball) with young adults experiencing past-month suicidal ideation. METHODS: The sample consisted of 50 participants. Lifetime discrimination and rejection sensitivity were assessed prior to Cyberball. Negative affect and problem-solving abilities were assessed pre- and post-Cyberball. SPSS and the PROCESS macro were used to test relations among variables of interest. RESULTS: Rejection sensitivity predicted greater problem-solving decrements, but not negative affect, following rejection among individuals who had experienced higher (vs. lower) levels of lifetime discrimination. CONCLUSION: Addressing rejection sensitivity and sources of discrimination within the context of treatment may reduce the impact of social rejection on problem-solving abilities among young adults at risk for suicide.

Impact of a Virtual Suicide Safety Planning Training on Clinician Knowledge, Self-Efficacy, and Use of Safety Plans in Community Mental Health Clinics.

OBJECTIVE: Safety planning is a critical evidence-based intervention used to prevent suicide among individuals who report suicidal ideation or behavior. There is a dearth of research on optimal ways to disseminate and implement safety plans in community settings. The present study examined one implementation strategy, a 1-hour virtual pre-implementation training, designed to teach clinicians to effectively use an electronic safety plan template (ESPT), integrated with suicide risk assessment tools, in the context of a measurement feedback system. We examined the effect of this training on clinician knowledge and self-efficacy in use of safety planning as well as ESPT completion rates. METHOD: Thirty-six clinicians across two community-based clinical psychology training clinics completed the virtual pre-implementation training as well as pre- and post-training knowledge and self-efficacy assessments. Twenty-six clinicians completed a 6-month follow-up term. RESULTS: Clinicians reported significant improvements in self-efficacy and knowledge from pre- to post-training. They retained significant improvements in self-efficacy and a trend toward greater knowledge at the 6-month follow-up. Of the clinicians who worked with suicidal youth, 81% attempted to use an ESPT and 63% successfully completed all sections of the ESPT. Reasons for partial completion included technological difficulties and time constraints. CONCLUSION: A brief virtual pre-implementation training can improve clinician knowledge and self-efficacy in use of an ESPT with youth at risk for suicide. This strategy also holds the potential to improve the adoption of this novel evidence-based intervention in community-based settings.

Venom of the neotropical rattlesnake, Crotalus culminatus: Intraspecific variation, neutralization by antivenoms, and immunogenicity in rabbits.

Crotalus culminatus is a medically significant species of rattlesnake in Mexico [1]. While the proteomic composition of its venom has been previously reported for both juvenile and adult specimens, there has been limited research into its functional properties, with only a few studies, including one focusing on coagulotoxicity mechanisms. In this study, we aimed to compare the biochemical and biological activities of the venom of juvenile and adult snakes. Additionally, we assessed antibody production using the venoms of juveniles and adults as immunogens in rabbits. Our findings reveal lethality and proteolytic activity differences between the venoms of juveniles and adults. Notably, juvenile venoms exhibited high proportions of crotamine, while adult venoms displayed a reduction of this component. A commercially available antivenom demonstrated effective neutralization of lethality of both juvenile and adult venoms in mice. However, it failed to neutralize the paralytic activity induced by crotamine, which, in contrast, was successfully inhibited by antibodies obtained from hyperimmunized rabbits. These results suggest the potential inclusion of C. culminatus venom from juveniles in commercial antivenom immunization schemes to generate antibodies targeting this small myotoxin.

Clinical signs, causes, and outcome of central cord syndrome in 22 cats.

OBJECTIVE: To describe the signalment, clinical findings, presumptive or definitive diagnosis, and outcome in cats with central cord syndrome (CCS). ANIMALS: 22 cats. CLINICAL PRESENTATION: Cats evaluated for CCS at 7 referral hospitals between 2017 and 2021 were included. Information retrieved from medical records included signalment, physical and neurological examination findings, diagnostic investigations, definitive or presumptive diagnosis, treatment, and follow-up. RESULTS: Median age at presentation was 9 years. Two neuroanatomical localizations were associated with CCS: C1-C5 spinal cord segments in 17 (77.3%) cats and C6-T2 spinal cord segments in 5 (22.7%) cats. Neuroanatomical localization did not correlate with lesion location on MRI in 8 (36.3%) cats. The most common lesion location within the vertebral column was over the C2 and C4 vertebral bodies in 6 (27.2%) and 5 (22.7%) cats, respectively. Peracute clinical signs were observed in 11 (50%) cats, acute in 1 (4.5%), subacute in 4 (18%), and chronic and progressive signs were seen in 6 (40.9%) cats. The most common peracute condition was ischemic myelopathy in 8 (36.3%) cats, whereas neoplasia was the most frequently identified chronic etiology occurring in 5 (22.7%) cats. Outcome was poor in 13 (59%) cats, consisting of 4 of 11 (36.6%) of the peracute cases, 3 of 4 (75%) of the subacute cases, and 6 of 6 of the chronic cases. CLINICAL RELEVANCE: Central cord syndrome can occur in cats with lesions in the C1-C5 and C6-T2 spinal cord segments. Multiple etiologies can cause CCS, most commonly, ischemic myelopathy and neoplasia. Prognosis depends on the etiology and onset of clinical signs.

The value of a head turn in neurolocalization.

BACKGROUND: A head turn is a clinically relevant abnormality identified on neurological examination and historically has been an isolated or concomitant sign of ipsilateral forebrain dysfunction. Experimental studies in quadrupedal mammals suggest that changes in head posture may be identified as originating in other parts of the central nervous system (CNS). OBJECTIVES: To identify whether other locations within the CNS could give rise to a head turn and whether the head turn identified is isolated or concomitant with other deviations in head and body posture. ANIMALS: Forty-nine client-owned dogs with a presentation of a head turn, from 6 veterinary referral centers. METHODS: Multicenter observational prospective study including dogs with photographic evidence of a head turn, full neurological examination, and advanced imaging. RESULTS: Of the population, 15/49 had head turn only, 9/49 had head turn and head tilt only, 12/49 had head turn and body turn only, and 13/49 had head turn, head tilt, and body turn. Nearly all dogs with forebrain disease (23/24), and, all with brainstem and cerebellar disease, had an ipsilateral head turn and body turn (if present). In the cerebellar group, all head tilts were contralateral to the lesion location. In the cervical spinal cord group, all head turns, body turns and head tilts were contralateral to the lesion location. CONCLUSION: A head turn, although most likely associated with, is not exclusively seen with forebrain disease. Certain combinations of head turn, head tilt and body turn suggest a neurolocalization other than the forebrain, with appropriate classification needed.

Increased risk of early lung function alterations in people with psychosis: A cross-sectional case-control study.

BACKGROUND: Tobacco smoking has been described as the main cause of chronic obstructive pulmonary disease (COPD) and this habit is clearly more frequent among individuals with psychosis than in the general population, with rates reaching up to 60%. However, little attention has been focused on the association of COPD and psychosis. We aimed to explore the risk of presenting early lung function alterations in a group of individuals with psychosis. METHODS: Following an observational cross-sectional design we studied a cohort of individuals with established psychosis (N=128), and compared them with a sex, age, and smoking habit matched control group (N=79). We evaluated respiratory symptoms by means of mMRC, CAT and Dyspnea-12 scales. And lung function through spirometry tests. RESULTS: Individuals with psychosis presented more respiratory symptoms than controls. Similarly, we observed significant differences in the lung function tests between these two groups, where individuals with psychosis presented worse results in most of the spirometry mean values (FEV1 or forced expiratory volume in the first one second: 3.29L vs. 3.75L, p<0.001; forced vital capacity or FVC: 4.25L vs. 4.72L, p=0.002; and FEV1/FVC ratio: 0.78 vs. 0.80, p=0.052). Patients also presented worse values of lung diffusion, with lower diffusing capacity for carbon monoxide (DLCO) than controls (6.95 vs. 8.54mmol/min/kPa, p<0.001). CONCLUSIONS: The individuals with psychosis in our study presented greater respiratory symptoms and poorer lung function measured through spirometry. These signs have been described as early signs of COPD.

Chemotherapy for the treatment of intracranial glioma in dogs.

Gliomas are the second most common primary brain tumor in dogs and although they are associated with a poor prognosis, limited data are available relating to the efficacy of standard therapeutic options such as surgery, radiation and chemotherapy. Additionally, canine glioma is gaining relevance as a naturally occurring animal model that recapitulates human disease with fidelity. There is an intense comparative research drive to test new therapeutic approaches in dogs and assess if results translate efficiently into human clinical trials to improve the poor outcomes associated with the current standard-of-care. However, the paucity of data and controversy around most appropriate treatment for intracranial gliomas in dogs make comparisons among modalities troublesome. To further inform therapeutic decision-making, client discussion, and future studies evaluating treatment responses, the outcomes of 127 dogs with intracranial glioma, either presumed (n = 49) or histologically confirmed (n = 78), that received chemotherapy as leading or adjuvant treatment are reviewed here. This review highlights the status of current chemotherapeutic approaches to intracranial gliomas in dogs, most notably temozolomide and lomustine; areas of novel treatment currently in development, and difficulties to consensuate and compare different study observations. Finally, suggestions are made to facilitate evidence-based research in the field of canine glioma therapeutics.

Modeling purple basil, sage, spearmint, and sweet basil responses to daily light integral and mean daily temperature.

Mean daily temperature (MDT) and daily light integral (DLI) can interact to influence growth and development of plants. Our objectives were to determine 1) the extent DLI and MDT influence growth and development of purple basil 'Dark Opal' (Ocimum basilicum), sage 'Extrakta' (Salvia officinalis), spearmint 'Spanish' (Mentha spicata), and sweet basil 'Nufar' (Ocimum basilicum) and 2) the influence on purple basil color. Young plants were transplanted into hydroponic systems in five greenhouse compartments with MDT set points of 23, 26, 29, 32, or 35°C and DLIs from 5 to 19 mol·m‒2·d‒1, respectively. At harvest, growth, development, and leaf color was measured. Branch number of all genera increased as MDT increased from ~23 to 35°C. Sweet basil branch number increased as DLI increased from 5.5 to 13.2 mol·m‒2·d‒1, but the effect of DLI was attenuated as MDT decreased. In contrast, increasing DLI from ~5-6 to ~18-19 mol·m‒2·d‒1 increased sage and spearmint branch number more when MDT was lower (~23°C) compared to ~35°C, while branch number of purple basil was not influenced by DLI. The optimal MDT (MDTopt) for sage and spearmint fresh mass decreased from 27.5 to 23.5°C and from 30.4 to 27.8°C, respectively, as DLI increased from 6 to 18 mol·m‒2·d‒1, while sweet basil fresh mass MDTopt increased from 32.6 to 35.5°C as DLI increased from 6 to 11 mol·m‒2·d‒1. Purple basil was greener [hue angle (h°) = 99° to 138°] when MDT was ~35°C regardless of DLI, but when MDT was lower (~25°C), basil was more purple (h° = 335°) at a DLI of 18.7 compared to 5.0 mol·m‒2·d‒1 (h° = 98°). Taken together, MDT and DLI can have a large impact on plant growth, development, and color and can be manipulated to achieve desired characteristics.

Hedgehog costimulation during ischemia-reperfusion injury potentiates cytokine and homing responses of CD4+ T cells.

Introduction: Ischemia reperfusion injury (IRI) confers worsened outcomes and is an increasing clinical problem in solid organ transplantation. Previously, we identified a "PtchHi" T-cell subset that selectively received costimulatory signals from endothelial cell-derived Hedgehog (Hh) morphogens to mediate IRI-induced vascular inflammation. Methods: Here, we used multi-omics approaches and developed a humanized mouse model to resolve functional and migratory heterogeneity within the PtchHi population. Results: Hh-mediated costimulation induced oligoclonal and polyclonal expansion of clones within the PtchHi population, and we visualized three distinct subsets within inflamed, IRI-treated human skin xenografts exhibiting polyfunctional cytokine responses. One of these PtchHi subsets displayed features resembling recently described T peripheral helper cells, including elaboration of IFN-y and IL-21, expression of ICOS and PD-1, and upregulation of positioning molecules conferring recruitment and retention within peripheral but not lymphoid tissues. PtchHi T cells selectively homed to IRI-treated human skin xenografts to cause accelerated allograft loss, and Hh signaling was sufficient for this process to occur. Discussion: Our studies define functional heterogeneity among a PtchHi T-cell population implicated in IRI.

Demographics, clinical findings and diagnoses of cranial thoracic myelopathies (T1-T6 vertebrae) in cats.

OBJECTIVES: The aim of the study was to describe the patient demographics, clinicopathological features and presumptive or final diagnoses in cats with myelopathies between the T1 and T6 vertebrae. METHODS: This retrospective multicentre case study enrolled cases between 2015 and 2022 that were diagnosed with myelopathies between the T1 and T6 vertebrae as the primary cause for the presenting clinical signs. RESULTS: A total of 21 cases matched the inclusion criteria, 13 males (11 castrated and 2 entire) and 8 spayed females (median age 93 months; range 5-192). Most of the cases presented with a chronic and progressive history (76% and 86%, respectively), with a median duration of 29 days (range 1-2880). At the time of presentation, 90% of the cases were localised to the T3-L3 spinal cord segments based on neurological examination. The most common underlying pathology was neoplasia (42.9%), followed by inflammatory (24%), anomalous (19%), degenerative (9.5%) and vascular (4.8%) disorders. The most common location was T3-T4 (29%), followed by T2-T3 and T5-T6 (19% each). The cutaneous trunci reflex was normal in 86% of the cases and most of the cases (71%) did not show spinal discomfort upon admission. CONCLUSIONS AND RELEVANCE: Neoplasia was the most common cause of cranial thoracic myelopathy in this study. The lack of pathognomonic clinical signs for this specific region highlights the importance of assessing the entire thoracolumbar region up to and including at least the T1 vertebra when investigating cases with signs consistent with a T3-L3 myelopathy.

Interpersonal stress and proinflammatory activity in emerging adults with a history of suicide risk: A pilot study.

Interpersonal stress during adolescence and young adulthood can threaten healthy developmental trajectories. A "primed" proinflammatory response to acute stress may serve as an underlying process that results in negative outcomes for youth. The present pilot study examined the relation between interpersonal stress and two proinflammatory cytokines in a sample of 42 university-recruited emerging adults with recent suicidal thoughts and behaviors. Participants completed self-report measures of mood, suicidal thoughts and behaviors, recent peer-related stressors, and interpersonal sensitivity. They also participated in an acute laboratory social stress task and provided three saliva samples to measure their proinflammatory responses (IL-6 and TNF-α) to the stressor. Participants reported significant increases in sadness and exclusion, and significant decreases in inclusion, following task participation. Importantly, no participants reported an increase in or onset of suicidal thoughts. No significant associations between interpersonal stress and proinflammatory cytokines were found. Changes in affect during the task coupled with lack of increased suicidal thoughts indicate it is acceptable to use this exclusion and rejection paradigm with this population, with proper debriefing and positive mood induction procedures. Given all other nonsignificant associations, future research considerations are discussed, including impact of COVID-19 on task potency and incorporation of multiple stress response systems.

Invasive Phenoprofiling of Acute-Myocardial-Infarction-Related Cardiogenic Shock.

BACKGROUND: Studies had previously identified three cardiogenic shock (CS) phenotypes (cardiac-only, cardiorenal, and cardiometabolic). Therefore, we aimed to understand better the hemodynamic profiles of these phenotypes in acute myocardial infarction-CS (AMI-CS) using pulmonary artery catheter (PAC) data to better understand the AMI-CS heterogeneity. METHODS: We analyzed the PAC data of 309 patients with AMI-CS. The patients were classified by SCAI shock stage, congestion profile, and phenotype. In addition, 24 h hemodynamic PAC data were obtained. RESULTS: We identified three AMI-CS phenotypes: cardiac-only (43.7%), cardiorenal (32.0%), and cardiometabolic (24.3%). The cardiometabolic phenotype had the highest mortality rate (70.7%), followed by the cardiorenal (52.5%) and cardiac-only (33.3%) phenotypes, with significant differences (p < 0.001). Right atrial pressure (p = 0.001) and pulmonary capillary wedge pressure (p = 0.01) were higher in the cardiometabolic and cardiorenal phenotypes. Cardiac output, index, power, power index, and cardiac power index normalized by right atrial pressure and left-ventricular stroke work index were lower in the cardiorenal and cardiometabolic than in the cardiac-only phenotypes. We found a hazard ratio (HR) of 2.1 for the cardiorenal and 3.3 for cardiometabolic versus the cardiac-only phenotypes (p < 0.001). Also, multi-organ failure, acute kidney injury, and ventricular tachycardia/fibrillation had a significant HR. Multivariate analysis revealed that CS phenotypes retained significance (p < 0.001) when adjusted for the Society for Cardiovascular Angiography & Interventions score (p = 0.011) and ∆congestion (p = 0.028). These scores independently predicted mortality. CONCLUSIONS: Accurate patient prognosis and treatment strategies are crucial, and phenotyping in AMI-CS can aid in this effort. PAC profiling can provide valuable prognostic information and help design new trials involving AMI-CS.

Facets of social problem-solving as moderators of the real-time relation between social rejection and negative affect in an at-risk sample.

Social rejection predicts negative affect, and theoretical work suggests that problem-solving deficits strengthen this relation in real-time. Nevertheless, few studies have explicitly tested this relation, particularly in samples at risk for suicide. This may be particularly important as social rejection and negative affect are significant predictors of suicide. The aim of the current study was to examine whether cognitive (i.e., perceiving problems as threats) and behavioral (i.e., avoidance) facets of problem-solving deficits moderated the real-time relation between social rejection and negative affect. The sample consisted of 49 young adults with past-month suicidal ideation. Demographic information, social problem-solving deficits, as well as depressive/anxiety symptoms and stress levels were assessed at baseline. Social rejection and negative affect were assessed using ecological momentary assessment over the following 28 days. Dynamic structural equation modeling was used to assess relations among study variables. After accounting for depressive/anxiety symptoms, stress levels, sex, and age, only avoidance of problems bolstered the real-time positive relation between social rejection severity and negative affect (b = 0.04, 95% credibility interval [0.003, 0.072]). Individuals with suicidal ideation who possess an avoidant problem-solving style may be particularly likely to experience heightened negative affect following social rejection and may benefit from instruction in problem-solving skills.

Trajectories of adolescent suicidal ideation and depressive symptoms during partial hospitalization: Clinical and demographic characteristics as predictors of change.

Partial hospital programs (PHPs) are a vital mental health service for youth at risk for suicide. Yet, few studies have examined trajectories of suicidal ideation and depressive symptoms, two important risk factors for suicidal behavior, over the course of care. Moreover, little is known about factors that may impact these trajectories among youth in PHPs. The present study examined trajectories of suicidal ideation and depressive symptoms, as well as clinical and demographic predictors of these changes, among youth enrolled in two PHPs. A sample of 253 youth (Mage = 15.3; SD = 1.4; range = 12-18; 68.8% female; 63.2% White; 75.1% non-Hispanic/Latino/a/x) completed repeated measures of suicidal ideation severity and depressive symptoms during treatment. Trajectories of these outcomes were examined using two separate latent growth models. Recent history of self-injurious behaviors and demographics were tested as predictors of trajectories using a taxonomic approach. Overall, suicidal ideation and depressive symptoms declined over the course of care. Sex, history of self-injury, and sexual identity were associated with variability in one or both trajectories of change. Results suggest individual variability in the rate of change among youth in PHPs. Such information may be used to aid in treatment planning and quality improvement efforts within PHPs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Examination of proinflammatory activity as a moderator of the relation between momentary interpersonal stress and suicidal ideation.

INTRODUCTION: Peer-related interpersonal stress can increase risk for suicidal thoughts among adolescents and young adults. However, not all individuals who undergo peer-related interpersonal stressors experience suicidal thoughts. Heightened proinflammatory activity is one factor that may amplify the relation between interpersonal stress and suicidal thinking. METHODS: This pilot study examined the relation between interpersonal stress and suicidal ideation in real time, as well as whether proinflammatory cytokine (IL-6 and TNF-α) activity across a laboratory social stressor moderated this association in a sample of 42 emerging adults with recent suicidal ideation. Participants completed 28 days of 6×/daily ecological momentary assessment that assessed for suicidal ideation (presence vs. absence, ideation intensity), occurrence of negative peer events, and feelings of exclusion. RESULTS: There was a trend for within-person increases in feelings of exclusion to be associated with increases in concurrent suicidal ideation intensity. Additionally, within-person increases in negative peer events were associated with increased odds of subsequent suicidal ideation among individuals with very low IL-6 activity. However, this finding is considered preliminary. CONCLUSION: Interventions targeting perceptions of exclusion and increasing social support may be of benefit. However, findings require replication in larger samples, and thus must be interpreted with caution.

Strength performance of low-bearing-capacity clayey soils stabilized with ladle furnace slag.

In this paper, the performance of ladle furnace slag (LFS), a by-product of secondary steel refining, is evaluated as a binder to stabilize clayey soils of low bearing capacity. The aim is to define whether additions of this by-product to clayey soil can stabilize the soil in accordance with the technical specifications of Spanish standards. To do so, three different soils stabilized with 5% LFS were compared with the same soils stabilized with 2% lime and with no stabilization, in order to investigate their different behaviors. The chemical and mineralogical characterizations of all the soil mixes were conducted using X-ray fluorescence, X-ray diffraction, and scanning electron microscopy. The Atterberg limit test was used to study the plastic behavior of the soils, and the results of compaction, bearing capacity, unconfined compressive strength, and direct shear strength (cohesion and friction angle) tests defined their strength characteristics. The analysis was completed with the pH monitoring of the mixes along the curing time in order to relate the pH changes with the strength evolution. The addition of LFS to the soils has resulted in an increase in the liquid limit and plastic limit, causing therefore a slight decrease in the plasticity index. All the soils showed increases between 30% and 70% in their California Bearing Ratios immediately after mixing with 5% LFS, and after 90 days of curing, improvements of 30-188% in their unconfined compressive strength were noted in comparison with untreated soil, which were higher than the lime-stabilized soils. The cohesion of soils stabilized with LFS at 28 days of curing obtained improvements ranging from 40 to 300% depending on the type of soil. However, the friction angle showed a slight increase of 10% in two of the soils and zero in another. The high initial pH in LFS-stabilized soils was maintained during the curing time, which favored the development of pozzolanic reactions that improve the soil strength. These results confirmed that the substitution of lime with LFS is a feasible option for soil stabilization.

Electrochemical Kinetics and Detection of Paracetamol by Stevensite-Modified Carbon Paste Electrode in Biological Fluids and Pharmaceutical Formulations.

Paracetamol (PCT), or acetaminophen, is an important drug used worldwide for various clinical purposes. However, the excessive or indiscriminate use of PCT can provoke liver and kidney dysfunction; hence, it is essential to determine the amount of this target in biological samples. In this work, we develop a quick, simple, and sensitive voltammetric method using chemically modified electrodes to determine PCT in complex matrices, including human serum and commercial solid formulations. We modify the carbon paste electrode with stevensite monoclinic clay mineral (Stv-CPE), using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy to characterise and detect PCT. The kinetics study provides a better electrochemical characterisation of the electrode behaviour, finding the detection and quantitation limits of 0.2 µM and 0.5 µM under favourable conditions. Further, the best linear working concentration range is 0.6-100 µM for PCT, applying the proposed method to the quantitative determination of PCT content in reference tablet formulations and biological samples for validation.