Search Results (219)

Blackwater rivers are enriched in humic acids and impoverished in nutrients, sometimes discharging into oceans. Brazil has a coastal zone of about 8700 km, with several blackwater rivers discharging into the Atlantic Ocean, in addition to the Rio Negro of the northern Amazon basin, which is the largest (about 1700 km long) and best-known tropical backwater river. On the other hand, only a few attempts have been made to deal with their hydrochemical composition and how it is related to the hydrochemistry of different water bodies nearby. This paper focuses on a sector of the Atlantic Ocean shore occurring in São Paulo State, enclosing two important Ecological Reserves, i.e., the Restinga State Park of Bertioga and the State Park of Serra do Mar–São Sebastião Nucleus, located at Bertioga and São Sebastião cities, respectively. Physicochemical parameters such as pH and electrical conductivity, as well as the composition of major constituents like sodium, potassium, calcium, magnesium, bicarbonate, chloride, sulfate, nitrate, etc., have been evaluated in two blackwater rivers and one blackwater stream to compare their relative inputs into the Atlantic Ocean. Traditional hydrogeochemical diagrams such as the Piper, Schoeller, Gibbs, van Wirdum, and Wilcox graphs were utilized for investigating the major features of the blackwater’s composition, revealing in some cases that they suffer an accentuated influence of the constituents occurring in the Atlantic Ocean waters, due to backward currents (coastal upwelling or tidal currents). Another highlight of this paper is the measurement of an enhanced concentration of dissolved iron in one blackwater sample analyzed, reaching a value of 1.9 mg/L. Such a finding has also been often reported in the literature for blackwater rivers and streams, as humic and fulvic acids are used to bind Fe³⁺, keeping it in solution. Nowadays, iron in solution has been considered a very important element acting as a natural fertilizer of the coastal ocean because it is an essential nutrient to marine phytoplankton. Full article

Silicon carbide (SiC) and silicon nanoparticle-decorated carbon (Si/C) materials are electrodes that can potentially be used in various rechargeable batteries, owing to their inimitable merits, including non-flammability, stability, eco-friendly nature, low cost, outstanding theoretical capacity, and earth abundance. However, SiC has inferior electrical conductivity, volume expansion, a low Li⁺ diffusion rate during charge–discharge, and inevitable repeated formation of a solid–electrolyte interface layer, which hinders its commercial utilization. To address these issues, extensive research has focused on optimizing preparation methods, engineering morphology, doping, and creating composites with other additives (such as carbon materials, metal oxides, nitrides, chalcogenides, polymers, and alloys). Owing to the upsurge in this research arena, providing timely updates on the use of SiC and Si/C for batteries is of great importance. This review summarizes the controlled design of SiC-based and Si/C composites using various methods for rechargeable metal-ion batteries like lithium-ion (LIBs), sodium-ion (SIBs), zinc-air (ZnBs), and potassium-ion batteries (PIBs). The experimental and predicted theoretical performance of SiC composites that incorporate various carbon materials, nanocrystals, and non-metal dopants are summarized. In addition, a brief synopsis of the current challenges and prospects is provided to highlight potential research directions for SiC composites in batteries. Full article

The mechanism by which voltage-gated ion channels open and close has been the subject of intensive investigation for decades. For a large class of potassium channels and related sodium channels, the consensus has been that the gating current preceding the main ionic current is a large movement of positively charged segments of protein from voltage-sensing domains that are mechanically connected to the gate through linker sections of the protein, thus opening and closing the gate. We have pointed out that this mechanism is based on evidence that has alternate interpretations in which protons move. Very little literature considers the role of water and protons in gating, although water must be present, and there is evidence that protons can move in related channels. It is known that water has properties in confined spaces and at the surface of proteins different from those in bulk water. In addition, there is the possibility of quantum properties that are associated with mobile protons and the hydrogen bonds that must be present in the pore; these are likely to be of major importance in gating. In this review, we consider the evidence that indicates a central role for water and the mobility of protons, as well as alternate ways to interpret the evidence of the standard model in which a segment of protein moves. We discuss evidence that includes the importance of quantum effects and hydrogen bonding in confined spaces. K⁺ must be partially dehydrated as it passes the gate, and a possible mechanism for this is considered; added protons could prevent this mechanism from operating, thus closing the channel. The implications of certain mutations have been unclear, and we offer consistent interpretations for some that are of particular interest. Evidence for proton transport in response to voltage change includes a similarity in sequence to the H_v1 channel; this appears to be conserved in a number of K⁺ channels. We also consider evidence for a switch in -OH side chain orientation in certain key serines and threonines. Full article

The scientific literature currently lacks studies that evaluate the nutritional composition of the tissues of cattle raised in different systems, so that the nutritional effects can be known and used to enhance consumption and use in the diet. The aim was therefore to assess whether the mineral content of muscle tissue (longissimus lumborum) in cattle finished during the rainy season in the Eastern Amazon is influenced by different farming systems. The treatments consisted of four systems (three pasture production systems and one feedlot system). 1. native wetland pasture in Santa Cruz do Arari (Mesoregion of Marajó); 2. native wetland pasture in Monte Alegre (Mesoregion of Baixo Amazonas); 3. cultivated dryland pasture in São Miguel do Guamá (Mesoregion of Nordeste Paraense); and 4. Confinement in Santa Izabel do Pará (Metropolitan Region of Belém). The analyses were carried out on samples of the longissimus lumborum muscle tissue of 48 male, castrated, crossbred Nelore cattle, twelve per breeding system, from commercial farms, destined for meat production, finished during the rainiest period of the year (between January and June). In systems 1 and 2, the animals were slaughtered in licensed slaughterhouses; the animals in systems 3 and 4 were slaughtered in commercial slaughterhouses. Food sampling and chemical analysis, soil sample collection and analysis, longissimus lumborum muscle tissue collection, sample preparation and digestion, and inductively coupled plasma optical emission spectrometry were evaluated. The experimental design was completely randomized in a linear model with four rearing systems and one period (rainy). The data was compared using the Statistical Analysis Systems (SAS) program. All analyses were carried out considering a significance level of 0.05. Samples of the diets offered (pasture and concentrate) were also collected. The Amazon systems influenced the macro- and micromineral content in the muscles of cattle (p < 0.05). The interaction between pasture systems vs. confinement showed differences in the minerals calcium (Ca), magnesium (Mg), phosphorus (P), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) (p < 0.05). However, there was no difference in the values of sodium (Na), potassium (K), and sulfur (S) between the rearing systems (p > 0.05). By contrast, the cultivated pasture system vs. extensive pasture showed differences in all the elements evaluated (p < 0.05). The rearing systems of the Eastern Amazon influenced the mineral content of beef, which continues to be an excellent source of macro- and microminerals and can compose the human diet. Full article

Epilepsy remains a major therapeutic challenge, with approximately one-third of patients experiencing drug-resistant epilepsy (DRE) despite the availability of multiple antiseizure medications (ASMs). This review aims to evaluate emerging ASMs—cenobamate, fenfluramine, ganaxolone, ezogabine (retigabine), and perampanel—with a focus on their mechanisms of action, pharmacological profiles, and potential role in precision medicine. A comprehensive literature search was conducted using PubMed, Scopus, and Web of Science to identify preclinical and clinical studies evaluating the pharmacodynamics, pharmacokinetics, efficacy, and safety of the selected ASMs. Relevant trials, reviews, and mechanistic studies were reviewed to synthesize the current understanding of their application in DRE and specific epilepsy syndromes. Each ASM demonstrated unique mechanisms targeting hyperexcitability, including the modulation of γ-aminobutyric acid receptor A (GABA-A) receptors, sodium and potassium channels, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptors), and serotonin systems. These mechanisms correspond with specific pathophysiological features in syndromes such as Dravet and Lennox–Gastaut. Evidence from clinical trials supports their use as adjunctive therapies with generally favorable tolerability, though adverse events and variable efficacy profiles were noted. The mechanistic diversity of these emerging ASMs supports their value in personalized epilepsy management, particularly in treatment-resistant cases. While the promise of precision medicine is evident, further studies are required to address challenges related to long-term safety, cost, and equitable access. Full article

Based on an integrated analysis, this study summarized the current status of soil quality in Yantai apple orchards, developed a multivariate regulation model for key soil physicochemical properties, and proposed optimized fertilization strategies to improve soil quality in the region. The study analyzed the physicochemical properties of the topsoil (0–30 cm) in 19 representative apple orchards across Yantai, including indicators like pH, organic matter (OM), major nutrient ions, and salinity indicators, using standardized measurements and multivariate statistical methods, including descriptive statistics analysis, frequency distribution analysis, canonical correlation analysis, stepwise regression equation analysis, and regression fit model analysis. The results demonstrated that in apple orchards across the Yantai region, reductions in pH were significantly mitigated under the combined increased OM and exchangeable calcium (Ca). Exchangeable potassium (EK) rose in response to the joint elevation of OM and available nitrogen (AN), and AN was also positively influenced by EK, while OM also exhibited a promotive effect on Olsen phosphorus (OP). Furthermore, Ca increased with higher pH. AN and EK jointly contributed to the increases in electrical conductivity (EC) and chloride ions (Cl), while elevated exchangeable sodium (Na) and soluble salts (SS) were primarily driven by EK. Accordingly, enhancing organic and calcium source fertilizers is recommended to boost OM and Ca levels, reduce acidification, and maintain EC within optimal limits. By primarily reducing potassium’s application, followed by nitrogen and phosphorus source fertilizers, the supply of macronutrients can be optimized, and the accumulation of Na, Cl, and SS can be controlled. Collectively, the combined analysis of soil quality status and the multivariate regulation model clarified the optimized fertilization strategies, thereby establishing a solid theoretical and practical foundation for recognizing the necessity of soil testing and formula fertilization, the urgency of improving soil quality, and the scientific rationale for nutrient input management in Yantai apple orchards. Full article

Non-conventional water sources (saline and brackish water) are viable options for crop cultivation. Current salt-tolerance research largely focuses on Na⁺ and Cl⁻, while other ions in these waters remain ill-understood. Synthetic seawater was a representative of saline and brackish water in a Design of Experiments (DoE) treatment design used to evaluate the effects of factors [synthetic seawater (0, 15, 30, or 45%, v/v, Instant Ocean^®), total inorganic nitrogen (0, 14, or 28 mM; 1 NH₄⁺:8 NO₃⁻ ratio), potassium (0, 9, or 21 mM), calcium (0, 2, or 5 mM), silicon (0, 0.03, or 0.09 mM) and zinc (0, 0.05, or 2 mM)] on seedlings for two varieties of Brassica juncea [‘Carolina Broadleaf’ (CB) and ‘Florida Broadleaf’ (FB)] using a hydroponic assay. In 30–45% synthetic seawater, 0.09 mM of silicon or 2 mM of calcium alleviated salt stress. In FB, 0.04–0.06 mM of silicon was optimal for the production of new leaves. The CB variety showed greater production of new leaves with 0.09 mM of silicon and 28 mM of potassium. Potassium and calcium are components of seawater, and a sodium chloride assay would not account for their interactions without a multivariate approach to evaluate salt tolerance. The seedling assay identified factors and established criteria for larger-scale harvest experiments. Full article

Redox regulation is crucial for the cardiac action potential, coordinating the sodium-driven depolarization, calcium-mediated plateau formation, and potassium-dependent repolarization processes required for proper heart function. Under physiological conditions, low-level reactive oxygen species (ROS), generated by mitochondria and membrane oxidases, adjust ion channel function and support excitation–contraction coupling. However, when ROS accumulate, they modify a variety of important channel proteins in cardiomyocytes, which commonly results in reducing potassium currents, enhancing sodium and calcium influx, and enhancing intracellular calcium release. These redox-driven alterations disrupt the cardiac rhythm, promote after-depolarizations, impair contractile force, and accelerate the development of heart diseases. Experimental models demonstrate that oxidizing agents reduce repolarizing currents, whereas reducing systems restore normal channel activity. Similarly, oxidative modifications of calcium-handling proteins amplify sarcoplasmic reticulum release and diastolic calcium leak. Understanding the precise redox-dependent modifications of cardiac ion channels would guide new possibilities for targeted therapies aimed at restoring electrophysiological homeostasis under oxidative stress, potentially alleviating myocardial infarction and cardiovascular dysfunction. Full article

Background: The development of cerebral organoids created from human pluripotent stem cells in 3D culture may greatly improve the discovery of neuropsychiatric medicines. Methods: In the current study we differentiated neural organoids from a human pluripotent stem cell line in vitro, recorded the development of neurophysiological activity using multielectrode arrays (MEAs) and characterized the neuropharmacology of synaptic signaling over 8 months in vitro. In addition, we investigated the ability of these organoids to display epileptiform activity in response to a convulsant agent and the effects of antiseizure medicines to inhibit this abnormal activity. Results: Single and bursts of action potentials from individual neurons and network bursts were recorded on the MEA plates and significantly increased and became more complex from week 7 to week 30, consistent with neural network formation. Neural spiking was reduced by the Na channel blocker tetrodotoxin but increased by the inhibitor of K_V7 potassium channels XE991, confirming the involvement of voltage-gated sodium and potassium channels in action potential activity. The GABA antagonists bicuculline and picrotoxin each increased the spike rate, consistent with inhibitory synaptic signaling. In contrast, the glutamate receptor antagonist kynurenic acid inhibited the spike rate, consistent with excitatory synaptic transmission in the organoids. The convulsant 4-aminopyridine increased spiking, bursts and synchronized firing, consistent with epileptiform activity in vitro. The anticonvulsants carbamazepine, ethosuximide and diazepam each inhibited this epileptiform neural activity. Conclusions: Together, our data demonstrate that neural organoids form inhibitory and excitatory synaptic circuits, generate epileptiform activity in response to a convulsant agent and detect the antiseizure properties of diverse antiepileptic drugs, supporting their value in drug discovery. Full article

Background/Objectives: Poor diet is a leading modifiable cause of chronic disease in the US. In addition to targeting nutrients of concern (saturated fat, added sugars, and sodium), nutrients with both inadequate intakes and associations with major health outcomes require identification. We aimed to identify priority nutrients to address both malnutrition and diet-related disease in the US population. Methods: An established method for identifying priority nutrients across multiple demographic groups was adapted for the US population. This method evaluates and scores nutrients consumed at insufficient or excessive levels, with proposed revised requirements, and shows associations with established health priorities, based on the degree of deviation from recommendations and the number of linked health priorities. Priority nutrients were defined as those scoring in the top 25%. For each priority nutrient, a comparison of intake levels against the Dietary Reference Intake (DRI) was conducted. Results: There were 21 of 24 nutrients with consumption below recommended levels in at least one demographic group. Certain nutrients, such as dietary fiber, vitamin D, and choline, exhibited particularly high inadequacy rates, exceeding 90% throughout different life stages. The highest priority nutrients included vitamin D, vitamin E, calcium, magnesium, and dietary fiber, with vitamin D, omega-3 fatty acids, zinc, folate, and potassium showing priority for specific demographic groups. Comparing current intake levels with those known to benefit health priorities indicated that higher intakes of vitamin D, vitamin E, and calcium could be beneficial. Conclusions: Ten essential nutrients play a role in the prevention of diet-related disease, yet are consumed inadequately across the US population, suggesting that the prioritization of these nutrients can help to address the burden of chronic disease. Priority nutrients should be considered in diet and nutrition policies and guidelines. Full article

Background: Early defibrillation improves outcomes in cardiac arrest, but the optimal defibrillation strategy and energy requirements remain debated. This study investigated whether arterial blood gas (ABG) parameters could predict optimal defibrillation energy requirements for achieving the highest first-shock success rates in an animal model. Our study focused on clinical scenarios where ABG measurements are readily available, such as ventricular tachycardia and ventricular fibrillation storms requiring multiple shock deliveries. Materials and Methods: In the experimental setting, ventricular fibrillation was induced by 50 Hz direct current (DC), and the defibrillation threshold (DFT) was determined using a stepwise defibrillation protocol. ABG parameters were measured before each defibrillation attempt, recording partial arterial pressure of carbon dioxide (PaCO₂) and oxygen (PaO₂), pH, hematocrit (Hct), sodium (Na⁺), potassium (K⁺), and bicarbonate (HCO₃⁻) levels. The relationships between ABG parameters and the DFT were analyzed for 15 subjects using classical data analysis techniques and machine learning (ML) algorithms. Multiple ML models were trained and tested to predict the higher energy needed for successful defibrillation based on the ABG parameters. Results: Statistically significant differences were found in Hct and Na⁺ levels between the two DFT categories, above 130 Joules (J) and below 40 J (p < 0.01). The DFT negatively correlated with PaO₂ and positively correlated with Hct and Na⁺. However, other ABG parameters did not show significant correlations with DFT. Using ML, we predicted cases requiring higher defibrillation E. Our best-performing model, the Extra Trees Classifier, achieved 83% overall accuracy, with 100% and 67% precision rates for higher and lower DFT categories, respectively. We validated the model using bootstrap resampling and 10-fold cross-validation, confirming consistent performance. We identified Hct, PaCO₂, and PaO₂ as significant contributors to model prediction based on the feature importance value. Conclusions: Modern data analysis techniques applied to ABG parameters may guide personalized defibrillation energy selection, particularly in controlled clinical environments such as catheterization laboratories and intensive care units where ABG measurements are readily available. Full article

Background and Objective: Dietary interventions are the first-line treatment for overweight individuals (OW) and individuals with obesity (OB) with high-normal blood pressure (BP) or grade I hypertension, especially when at low-to-moderate cardiovascular risk (CVR). However, current guidelines do not specify the most effective dietary approach for optimising cardiovascular and metabolic outcomes in this population. This study aimed to compare the effects of a low-calorie, high-protein ketogenic diet (KD) vs. a low-calorie, low-sodium, and high-potassium Mediterranean diet (MD) on BP profiles assessed via ambulatory BP monitoring (ABPM), as well as on anthropometric measures, metabolic biomarkers, and body composition evaluated by bioelectrical impedance analysis (BIA). Methods: This prospective observational bicentric pilot study included 26 non-diabetic adult outpatients with central OW status or OB status (body mass index, BMI > 27 kg/m²) and high-normal BP (≥130/85 mmHg) or grade I hypertension (140–160/90–100 mmHg), based on office BP measurements. All participants had low-to-moderate CVR according to the second version of the systemic coronary risk estimation (SCORE2) and were selected and categorized as either KD (n = 15) or MD (n = 11). Comprehensive blood analysis, BIA, and ABPM were conducted at baseline and after three months. Results: At baseline, no significant differences were observed between the groups. Following three months of dietary intervention, both groups exhibited substantial reductions in body weight (KD: 98.6 ± 13.0 to 87.3 ± 13.4 kg; MD: 93.8 ± 17.7 to 86.1 ± 19.3 kg, p < 0.001) and waist circumference. Mean 24 h systolic BP (SBP) and diastolic BP (DBP) significantly declined in both groups (24 h mean SBP decreased from 125.0 ± 11.3 to 116.1 ± 8.5 mmHg (p = 0.003) and 24 h mean DBP decreased from 79.0 ± 8.4 to 73.7 ± 6.4 mmHg (p < 0.001)). Fat-free mass (FFM) increased, whereas fat mass (FM), blood lipid levels, and insulin concentrations decreased significantly. The ΔFM/ΔFFM correlates with ABP improvements. However, no significant between-group differences were detected at follow-up. Conclusions: The KD and the MD mediated weight loss and body composition changes, effectively improving bio-anthropometric and cardiovascular parameters in individuals with OW status or OB status and high BP. Although more extensive studies are warranted to elucidate potential long-term differences, our findings suggest the manner in which these two different popular dietary approaches may equally confer metabolic and cardiovascular benefits, emphasising the importance of weight and FM loss. Full article

Electrolytes play crucial roles in regulating nerve and muscle functions. Currently, microneedle technology enables real-time electrolyte monitoring through minimally invasive methods. However, due to the small size of microneedles, performing multi-layer modifications on individual microneedles and ensuring the integrity of these layers pose significant challenges. Additionally, the puncture efficiency of the electrodes will be affected by the structure of microneedle array integration. To address these issues, we primarily focus on developing a multi-parameter ion monitoring system based on microneedle arrays. By optimizing the surface reconstruction of electrode substrates, the adhesion between the electrode surface and the modification layer was improved, enhancing the stability of the electrodes. Potassium, sodium, and calcium ion-selective electrodes based on microneedles were fabricated, demonstrating good sensitivity and linearity. To tackle the puncture efficiency of microneedle arrays, finite element simulation was employed to investigate the mechanical properties of different structural designs of microneedle arrays during skin insertion. Ultimately, an integrated microneedle array was designed and assembled, and a multi-parameter ion monitoring system was developed, validated through in vitro simulations and in vivo animal experiments. This research provides valuable insights into the development and advancement of minimally invasive, multi-parameter dynamic monitoring technologies in clinical settings. Full article

Ion channels are proteins that regulate the flow of ions across cell membranes, playing a vital role in cervical cancer development and progression. These channels serve as both potential diagnostic markers and therapeutic targets, offering new opportunities for cancer treatment. Moreover, ion channels are crucial molecular indicators and possible therapeutic targets due to their role in the development of cervical cancer. Our review focuses on the various types of ion channels which are associated with cervical cancer (CCa), including sodium, calcium, and potassium channels. In our review, we clarify their diagnostic and prognostic value, as well as their relationship to the prognosis and stage of the disease. We also examine how ion channels contribute to the metastasis of cervical cancer, specifically in relation to their influence on cell motility, invasion, and interaction with the tumor microenvironment. By examining preclinical and clinical research involving ion channel blockers and modulators, we also highlight the therapeutic potential of targeting ion channels. We have demonstrated the available assays and imaging methods based on ion channel activity as examples of emerging diagnostic breakthroughs that show promise for enhancing the early detection of cervical cancer. Additionally, the possibility that ion channel modulator-based combination therapy could improve the efficacy of traditional treatments is investigated. To demonstrate the potential of ion channels in cervical cancer diagnosis and treatment, our review highlights the current challenges and the promising role in cervical cancer diagnostics and therapy. Full article

Minerals and trace elements are vital for numerous physiological processes in mammals. The current reference analysis for mineral determination in biological matrices is inductively coupled plasma mass spectrometry (ICP-MS). This analysis is costly, time-consuming, and destructive. While commercial kits are a viable alternative to ICP-MS due to the lower cost, their limit lies in the ability of determining only one mineral at a time. Energy-dispersive X-ray fluorescence (ED-XRF) has been proposed as a potential alternative for the rapid determination of mineral concentration in biological matrices. This study evaluated the accuracy of ED-XRF as an alternative to commercial diagnostic kits to predict the concentrations of sodium, magnesium, phosphorus, chloride, potassium, calcium, iron, and selenium in cattle plasma without sample pretreatment, potentially reducing the time of analysis compared to commercial kits and costs and labor compared to ICP-MS. Reference mineral concentrations were determined in 277 samples using in vitro diagnostics regulation-certified commercial diagnostic kits. The results indicated a moderate prediction accuracy only for potassium. For the other minerals, the prediction accuracy of ED-XRF was insufficient, which suggests that some degree of sample preparation is necessary to improve the determination of minerals in plasma. Full article