Search Results (140)

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

With the rapid advancement of electronic devices toward higher frequencies, faster speeds, increased integration, and miniaturization, the resulting elevated operating temperatures pose significant challenges to the performance and longevity of electronic components. These developments have intensified the demand for high-performance thermal interface materials (TIMs). Conventional silicone rubber-based TIMs often suffer from silicone oil-bleeding and the volatilization of low-molecular-weight siloxanes under elevated temperatures and mechanical stress. The release of these volatile organic compounds can lead to their deposition on circuit boards and electronic components, causing signal interference or distortion in optical and electronic systems, ultimately compromising device functionality. Additionally, the intrinsic thermal conductivity of traditional TIMs is insufficient to meet the escalating demands for efficient heat dissipation. To overcome these limitations, this study introduces a novel, non-silicone TIM based on a calcium ion-crosslinked sodium alginate matrix, prepared via ion-exchange curing. This bio-derived polymer matrix serves as an environmentally benign alternative to silicone rubber. Furthermore, a brush-coating technique is employed to induce the oriented alignment of boron nitride (BN) fillers within the alginate matrix. Experimental characterization reveals that this aligned microstructure markedly enhances the thermal conductivity of the composite, achieving a value of 7.87 W·m⁻¹·K⁻¹. The resulting material also exhibits outstanding thermal and mechanical stability, with no observable leakage or condensate formation under high-temperature and high-pressure conditions. This work offers a new design paradigm for environmentally friendly, high-performance TIMs with considerable potential for advanced electronic and optoelectronic applications. Full article

Excessive Zn(II) ions in aquatic environments pose significant risks to both human health and ecological systems due to their toxic effects, bioaccumulation potential, and interference with essential biological processes. To address this issue, a novel analcime@calcium aluminate@polyethylene glycol 400 (ACP) nanocomposite was fabricated using the hydrothermal technique, alongside an analcime@calcium aluminate (AC) nanocomposite for the efficient elimination of Zn(II) ions from aqueous media. X-ray diffraction (XRD) analysis affirmed the successful formation of crystalline phases, revealing average crystallite sizes of 72.93 nm for AC and 63.60 nm for ACP. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the nanocomposites, showing that AC primarily contained oxygen, sodium, aluminum, silicon, and calcium, whereas ACP incorporated 19.3% carbon due to the polyethylene glycol 400. Field emission scanning electron microscopy (FE-SEM) revealed that AC exhibited hexagonal and platelet-like structures, whereas ACP displayed more dispersed and layered morphologies. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of stacked platelet-like structures in AC and more defined, separated nanosheets in ACP. The maximum adsorption capacities of AC and ACP were 149.93 and 230.95 mg/g, respectively. The adsorption pathway of Zn(II) ions onto ACP nanocomposite involved three primary interactions: electrostatic attraction facilitated by calcium aluminate, ion exchange provided by analcime, and complexation promoted by polyethylene glycol 400. Thermodynamic analysis indicated that the adsorption process was exothermic, spontaneous, and primarily chemical in nature. Kinetic modeling confirmed that adsorption followed the pseudo-second-order model, while isotherm studies demonstrated adherence to the Langmuir model, indicating monolayer adsorption on homogeneous sites. Full article

The purification of waste cooking oils (WCOs) through clay-based adsorption is an established recycling method, yet the relationship between clay composition and adsorption efficiency remains an area of active research. The aim of the present research work was to assess the performance of Maghnia bentonite in WCO decoloration and to gain information about the specific refining process. Thus, natural bentonite from the Maghnia region (Algeria) was investigated as an adsorbent for WCO refining for biolubricant production. The adsorption efficiency was evaluated under different conditions, achieving up to 70% decolorization at 10 wt% clay after 4 h of treatment. Structural characterization of the bentonite before and after adsorption was conducted using FT-IR spectroscopy, powder X-ray diffraction (XRD), and X-ray fluorescence (XRF) to assess compositional and morphological changes. FT-IR analysis confirmed the adsorption of organic compounds, XRD indicated minor alterations in interlayer spacing, and XRF revealed ion exchange mechanisms, including a reduction in sodium and magnesium and an increase in calcium and potassium. Adsorption kinetics followed a pseudo-second-order model, with desorption effects observed at prolonged contact times. The pHPZC of 8.3 suggested that bentonite adsorption efficiency is enhanced under acidic conditions. The high decoloration capacity of Maghnia bentonite, combined with the availability and the low cost of the material, suggests a possible industrial application of this material for WCO refinement, especially in lubricant production. Full article

Phosphorus is one of the most abundant minerals in the body and plays a critical role in numerous cellular and metabolic processes. Most of the phosphate is deposited in bones, 14% is present in soft tissues as various organic phosphates, and only 1% is found in extracellular space, mainly as inorganic phosphate. The plasma inorganic phosphate concentration is closely maintained between 2.5 and 4.5 mg/dL by intertwined interactions between fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), and vitamin D, which tightly regulate the phosphate trafficking across the gastrointestinal tract, kidneys, and bones. Disruption of the strict hemostatic control of phosphate balance can lead to altered cellular and organ functions that are associated with high morbidity and mortality. In the past three decades, there has been a steady increase in the prevalence of kidney failure (KF) among populations. Individuals with KF have unacceptably high mortality, and well over half of deaths are related to cardiovascular disease. Abnormal phosphate metabolism is one of the major factors that is independently associated with vascular calcification and cardiovascular mortality in KF. In early stages of CKD, adaptive processes involving FGF-23, PTH, and vitamin D occur in response to dietary phosphate load to maintain plasma phosphate level in the normal range. However, as the CKD progresses, these adaptive events are unable to overcome phosphate retention from continued dietary phosphate intake and overt hyperphosphatemia ensues. As these hormonal imbalances and the associated adverse consequences are driven by the underlying hyperphosphatemic state in KF, it appears logical to strictly control serum phosphate. Conventional dialysis is inadequate in removing phosphate and most patients require dietary restrictions and pharmacologic interventions to manage hyperphosphatemia. However, diet control comes with many challenges with adherence and may place patients at risk for inadequate protein intake and malnutrition. Phosphate binders help to reduce phosphate levels but come with a sizable pill burden and high financial costs and are associated with poor adherence and psychosocial issues. Additionally, long-term use of binders may increase the risk of calcium, lanthanum, or iron overload or promote gastrointestinal side effects that exacerbate malnutrition and affect quality of life. Given the aforesaid challenges with phosphorus binders, novel therapies targeting small intestinal phosphate absorption pathways have been investigated. Recently, tenapanor, an agent that blocks paracellular absorption of phosphate via inhibition of enteric sodium–hydrogen exchanger-3 (NHE3) was approved for the treatment of hyperphosphatemia in KF. While various clinical tools are now available to manage hyperphosphatemia, there is a lack of convincing clinical data to demonstrate improvement in outcomes in KF with the lowering of phosphorus level. Conceivably, deleterious effects associated with hyperphosphatemia could be attributable to disruptions in phosphorus-sensing mechanisms and hormonal imbalance thereof. Further exploration of mechanisms that precisely control phosphorus sensing and regulation may facilitate development of strategies to diminish the deleterious effects of phosphorus load and improve overall outcomes in KF. Full article

Background and Objectives: Brain natriuretic peptide (NT-proBNP) is a biomarker widely used in diagnosing and monitoring heart failure. Its impact on electrolyte homeostasis is known, particularly for sodium. However, its relationship with serum calcium remains unclear. This retrospective observational study aimed to investigate the longitudinal association between NT-proBNP and serum calcium levels in a cohort of hospitalized patients with the goal of determining whether NT-proBNP could have a direct or indirect impact on calcium metabolism. Materials and Methods: We included 688 patients with 1022 repeated measurements of NT-proBNP and serum calcium collected during hospitalization from March 2022 to February 2025. Linear mixed models (LMMs) were employed to analyze longitudinal associations, adjusting for age, eGFR, estimated plasma volume status (ePVs), CRP, potassium, and albumin. Results: Baseline analysis revealed a negative correlation between NT-proBNP and serum calcium (r = −0.23, p < 0.001). Univariate LMM demonstrated a significant negative association (β = −1.3 × 10⁻⁵, p < 0.001), which remained significant in multivariate analysis (β = −6.9 × 10⁻⁶, p = 0.01), accounting for intrasubject variability. This suggests that as NT-proBNP increases, serum calcium levels decrease within individual patients, independent of confounders. This study’s findings indicate that NT-proBNP may influence calcium excretion, possibly through mechanisms involving the sodium–calcium exchanger (NCX) in renal tubules, similar to its effects on sodium homeostasis. Conclusions: This is the first study to evaluate the longitudinal impact of NT-proBNP on serum calcium, highlighting a potential clinical relevance in patients with cardiac dysfunction. Limitations include a retrospective design and a lack of urine calcium data. Further research is warranted to validate these findings and elucidate the underlying mechanisms. Full article

A membrane system was applied for ultrapure water production from the treatment of saline effluent from the canned food industry. The industrial effluent presented a high saline concentration, including sodium chloride, calcium carbonate, calcium sulfates, and magnesium. The effluent was treated using a system of reverse osmosis (RO) and a post-treatment process consisting of ion exchange resins (IEXRs). The RO was accompanied by the addition of a hexametaphosphate dose (2, 6, and 10 mg/L) as an antiscalant to avoid the RO membrane scaling by minerals. In turn, IEXRs were used for water deionization to produce ultrapure water with a reduced concentration of monovalent ions. The antiscalant dose was 6 mg/L, producing clean water from RO permeates with an efficiency of 65–70%. The brine from RO was projected for its reuse in food industry processes. The clean water quality from RO showed 20% total dissolved solids (TDS) removal (equivalent to salts). The antiscalant inhibited the formation of calcium salt incrustation > 200 mg/L, showing low fouling. In turn, anionic resins removed 99.8% of chloride ions, whereas the monovalent salts were removed by a mix of cationic–anionic resin, producing ultrapure water with electrical conductivity < 3.3 µS/cm. The cost of ultrapure water production was 2.62 USD/m³. Full article

Soil salinity is a major global challenge, reducing fertility and crop productivity. This study evaluated the effects of various soil management practices on the physical, chemical, and microbial properties of saline soils. Six treatments, combining loosening, ploughing, disking, and gypsum amendment, were applied to solonetzic meadow soil with high sodium levels. Soil penetration resistance was measured using a Penetronik penetrometer, while chemical analyses included pH, total salt content, calcium carbonate (CaCO₃), humus, and exchangeable cations (Na⁺, K⁺, Ca²⁺, Mg²⁺). Microbial composition was determined through DNA extraction and nanopore sequencing. The results showed that level A had the lowest penetration resistance (333 ± 200 N/m²), indicating better conditions for plant growth. Gypsum and loosening treatment significantly improved penetration resistance (141 N/m², p < 0.001), while gypsum amendment enhanced chemical properties (p < 0.05, p < 0.01, and p < 0.001). Gypsum application balanced soil parameters and influenced microbial communities. Reduced tillage favored functionally important microbial genera but did not support fungal diversity (p > 0.05). These findings highlight the effectiveness of gypsum amendment and tillage practices, like loosening and disking, in mitigating salinity stress and fostering beneficial microbial communities. Combining gypsum with these tillage methods proved most effective in enhancing soil health, offering insights for sustainable soil management in saline environments. Full article

Previous studies have observed alterations in excitation–contraction (EC) coupling during end-stage heart failure that include action potential and calcium (Ca²⁺) transient prolongation and a reduction of the Ca²⁺ transient amplitude. Underlying these phenomena are the downregulation of potassium (K⁺) currents, downregulation of the sarcoplasmic reticulum Ca²⁺ ATPase (SERCA), increase Ca²⁺ sensitivity of the ryanodine receptor, and the upregulation of the sodium–calcium (Na⁼-Ca²⁺) exchanger. However, in human heart failure (HF), debate continues about the relative contributions of the changes in calcium handling vs. the changes in the membrane currents. To understand the consequences of the above changes, they are incorporated into a computational human ventricular myocyte HF model that can explore the contributions of the spontaneous Ca²⁺ release from the sarcoplasmic reticulum (SR). The reduction of transient outward K⁺ current (I_to) is the main membrane current contributor to the decrease in RyR2 open probability and L-type calcium channel (LCC) density which emphasizes its importance to phase 1 of the action potential (AP) shape and duration (APD). During current-clamp conditions, RyR2 hyperphosphorylation exhibits the least amount of Ca²⁺ release from the SR into the cytosol and SR Ca²⁺ fractional release during a dynamic slow–rapid–slow (0.5–2.5–0.5 Hz) pacing, but it displays the most abundant and more lasting Ca²⁺ sparks two-fold longer than a normal cell. On the other hand, under voltage-clamp conditions, HF by decreased SERCA and upregulated I_NCX show the least SR Ca²⁺ uptake and EC coupling gain, as compared to HF by hyperphosphorylated RyR2s. Overall, this study demonstrates that the (a) combined effect of SERCA and NCX, and the (b) RyR2 dysfunction, along with the downregulation of the cardiomyocyte’s potassium currents, could substantially contribute to Ca²⁺ mishandling at the spark level that leads to heart failure. Full article

New homogeneous bilayer membranes with a thin anion-exchange layer have been developed based on the copolymer of N,N-diallyl-N,N-dimethylammonium chloride (DADMAC) and ethyl methacrylate (EMA) on the surface of a membrane substrate made from polyfluorosulfonic acid (PFSA). The overall and partial current–voltage characteristics, as well as external and internal diffusion-limiting currents, were theoretically and experimentally investigated. Parameters such as specific conductivity, sorption, and diffusion permeability of individual membrane layers were determined, along with effective transport numbers and specific permselectivity of the bilayer homogeneous membranes in mixed solutions of calcium chloride and sodium chloride. It was found that applying a thin anion-exchange layer of DADMAC and EMA to the homogeneous membrane allows for the creation of a charge-selective bilayer membrane with enhanced selectivity toward monovalent metal cations. The specific selectivity of the bilayer membrane for sodium cations increases more than 6-fold (from 0.8 to 4.8). Verification of the obtained experimental data was performed within a four-layer mathematical model with quasi-equilibrium boundary conditions for the diffusion layer (I)/modifying layer (II)/membrane substrate (III)/diffusion layer (IV) in ternary NaCl+CaCl₂ solutions. Full article

Phosphogypsum is a by-product of the wet-process phosphoric acid production, and it is rich in Ca and S. Long-term storage of Phosphogypsum can cause serious pollution to the environment; therefore, promoting the sustainable utilization of Phosphogypsum is crucial. This study proposes the use of Phosphogypsum and silicic acid in a sodium hydroxide solution for the hydrothermal synthesis of porous calcium silicate hydrate adsorbent, which is used for adsorbing Fe²⁺ from simulated hydrochloric acid pickling wastewater. Under the optimal synthesis conditions (37.5 g/L of NaOH, calcium/silicon ratio of 1.0, liquid/solid ratio of 15:1 mL/g, 110 °C, and 4 h), the conversion rate of SO₄²⁻ in Phosphogypsum is 87.41%. Porous calcium silicate hydrate exhibits excellent OH⁻ release capability in Fe²⁺-containing pickling wastewater. The adsorption process for Fe²⁺; is mainly chemical adsorption, involving ion exchange between Ca²⁺ and Fe²⁺, as well as complexation reactions of O-Si-O group, -OH group, and Si-O group with Fe²⁺. This technology aims to provide a solution for the sustainable utilization of Phosphogypsum and the recovery of Fe²⁺ from pickling wastewater, which has significant practical importance. Full article

Mulching plays a pivotal role in modern sustainable agriculture, offering a versatile solution to enhance soil quality, improve soil health, conserve resources, and optimize crop performance. This study examined the effects of various mulching materials on soil properties, seasonal variations in soil and environmental variables, and yam production in a tropical environment, with a focus on sustainable agricultural practice. We applied a range of mulch treatments, including black polythene, weedmat, sugarcane straw, organic compost, cowpea-live, juncao grass, sawdust, and a control with no mulch. The results indicated that the organic compost mulch significantly increased soil pH and soil electrical conductivity (EC). The control treatment resulted in the highest soil moisture content, while the highest soil temperature were recorded for the black polythene and organic compost mulch treatments. The organic compost mulch enhanced the soil organic carbon (SOC) content, soil available phosphorus (SAP) content, and soil exchangeable calcium (SECa) content. The weedmat mulch showed the highest soil exchangeable potassium (SEK) content, and the control treatment exhibited the highest soil exchangeable magnesium (SEMg) and sodium (SENa) content. In terms of micronutrients, the sawdust mulch and black polythene mulch significantly increased soil exchangeable iron (SEFe) and copper (SECu) levels, respectively. Notable seasonal variations in soil pH, temperature, and environmental humidity were observed during the crop period. The soil pH fluctuated from slightly acidic levels in August 2023 to neutral levels in October, and then decreased to slightly acidic levels in early 2024 before stabilizing by March 2024. The soil temperature peaked in November and dropped in January, while the environmental humidity ranged from 48.25% in December to 76.33% in February. The study demonstrated that the organic compost mulch stood out as an advantageous choice because of its capacity to enhance the soil’s properties and offer a balanced nutrient mix, making it particularly beneficial for yam cultivation. It also proved to be a reliable and balanced option to enhance soil quality with stable soil quality indices (SQIs). The weedmat mulch proved to be highly effective in enhancing yam growth and productivity. The weedmat mulch is the most profitable and cost-effective option for yam cultivation, providing the highest net returns and strong financial viability. This study emphasizes the value of choosing the right mulching materials to support soil quality, crop productivity, and economic returns in tropical settings, making strides toward more sustainable farming practices. Full article

A comprehensive understanding of the characteristics and formation mechanisms of groundwater in mining areas is essential for the effective prevention of coal mine water and the rational management of groundwater resources. The objective of this study was to examine the hydrogeochemical characteristics and evolution of Ordovician groundwater in the Zhuozishan coal mine, located in the northwest region of China. A total of 34 groundwater samples were collected for hydrogeochemical analyses and the investigation of their evolution processes, with the aid of a piper trilinear diagram, a Gibbs diagram, and an ion ratio diagram. The results indicate that the concentration of sodium (Na⁺), potassium (K⁺), bicarbonate (${\mathrm{HCO}}_3^{-}$), chloride (Cl⁻), sulphate (${\mathrm{SO}}_4^{2-}$), total dissolved solids (TDS), and pH increases from the recharge area to the discharge area, whereas the concentration of calcium (Ca²⁺) and magnesium (Mg²⁺) decreases. The hydrogeochemical characteristics of the runoff from Zhuozishan to Gongdeer coalfield and further southward display a notable north–south directional change. The groundwater process is primarily controlled by rock weathering action and cation exchange, with Na⁺ and K⁺ deriving primarily from cation exchange and only to a minor extent from halite dissolution. In conclusion, the northern part of the coalfield is characterised by a geological structure that creates a retention area with groundwater, resulting in an unordered runoff process with a complex formation mechanism. The middle region is devoid of geological constraints that would alter the flow direction, thus simplifying the process of groundwater formation. In contrast, the southern area experiences an increase in strata depth and fault blocking, which creates a retention zone, thereby rendering the groundwater formation process more complex. This research contributes to the effective management of groundwater resources in this coalfield and other mining sites. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that lacks effective treatment strategies to halt or delay its progression. The homeostasis of Ca²⁺ ions is crucial for ensuring optimal cellular functions and survival, especially for neuronal cells. In the context of PD, the systems regulating cellular Ca²⁺ are compromised, leading to Ca²⁺-dependent synaptic dysfunction, impaired neuronal plasticity, and ultimately, neuronal loss. Recent research efforts directed toward understanding the pathology of PD have yielded significant insights, particularly highlighting the close relationship between Ca²⁺ dysregulation, neuroinflammation, and neurodegeneration. However, the precise mechanisms driving the selective loss of dopaminergic neurons in PD remain elusive. The disruption of Ca²⁺ homeostasis is a key factor, engaging various neurodegenerative and neuroinflammatory pathways and affecting intracellular organelles that store Ca²⁺. Specifically, impaired functioning of mitochondria, lysosomes, and the endoplasmic reticulum (ER) in Ca²⁺ metabolism is believed to contribute to the disease’s pathophysiology. The Na+-Ca²⁺ exchanger (NCX) is considered an important key regulator of Ca²⁺ homeostasis in various cell types, including neurons, astrocytes, and microglia. Alterations in NCX activity are associated with neurodegenerative processes in different models of PD. In this review, we will explore the role of Ca²⁺ dysregulation and neuroinflammation as primary drivers of PD-related neurodegeneration, with an emphasis on the pivotal role of NCX in the pathology of PD. Consequently, NCXs and their interplay with intracellular organelles may emerge as potentially pivotal players in the mechanisms underlying PD neurodegeneration, providing a promising avenue for therapeutic intervention aimed at halting neurodegeneration. Full article

This study investigates the Batha endorheic basin in Chad, situated east of the Lake Chad basin in the arid to semi-arid Sahelian zone. This region has not yet undergone comprehensive geological and hydrogeological studies. More broadly, the transition zone between semi-arid and arid climates has been minimally explored. This research aims to evaluate the resources and dynamics of this multi-layered system using a combined geology-hydrogeology-hydrochemistry-isotopes approach. The multilayer system includes sedimentary layers (Quaternary, Pliocene, and Eocene) over a crystalline basement. A piezometric investigation of the system shows a general SE–NW groundwater, indicating an interconnection between all layers. Hydrochemical analyses identifies four main facies (calcium-bicarbonate, sodium-bicarbonate, sulphate-sodium, and mixed), primarily controlled by water–rock interaction with secondary influences from base-exchange and evaporation. Saturation indices indicate that these waters are close to equilibrium with the calcite-Mg phases, gaylussite and gypsum. Stable isotopes (oxygen-18 and deuterium) categorize groundwater into three groups: ancient water, recent and older meteoric water mixtures affected by evaporation, and mixtures more heavily impacted by evaporation. Tritium contents reveal three groups: current rainwater, modern water, and sub-modern water. These results indicate that ionic and isotopic differentiations cannot be strictly linked to specific layers, confirming the interconnected nature of the Batha system. The observed heterogeneity is mainly influenced by lithological and climatic variations. This study, though still limited, enhances significantly the understanding of the basin’s functioning and supports the rational exploitation of its vital resources for the Batha area’s development. Future investigations to complete the present study are highlighted. Full article