Low Buffering Capacity Research Articles

Salivary Physicochemical Parameters in Relation to Dental Caries and Adiposity Status.

The objective of this study was to investigate the correlations between salivary physicochemical parameters, adiposity, and caries indices in Hong Kong adolescents. A total of 921 adolescents aged 12-15 years from four randomly selected local secondary schools were invited to participate in this cross-sectional study. Dental examinations including the number of decayed, missing, and filled teeth (DMFT), salivary physicochemical parameters, and anthropometric measurements were performed. The Mann-Whitney U test was used to examine the differences in salivary parameters and adiposity indices between participants with different levels of caries experience. Correlations between adiposity indices, salivary parameters, and caries indices were examined using Spearman's correlation coefficients. The participation rate was 83.6%. After exclusion, data from 695 adolescents were analysed. Adolescents with high caries experience (DMFT ≥ Significant Caries Index [SiC Index]) had significantly higher weight-to-height ratio (W/H) and waist circumference (WC) z-scores and lower unstimulated and stimulated salivary flow rates and buffering capacity than those with DMFT < SiC Index. Except for body mass index z-score, the other adiposity indices were negatively correlated with at least one salivary physicochemical parameter (stimulated salivary flow rate or salivary buffering capacity) (rs ranged from -0.078 to -0.132). After adjusting for age and sex, decreased stimulated salivary flow rate was associated with higher body fat percentages, WC, and waist-to-height ratio z-scores, whereas low salivary buffering capacity was associated with higher W/H and WC z-scores. There is a potential link between adiposity indices and certain salivary physicochemical parameters that are implicated in the aetiology of dental caries.

Paradoxical metabolic acidosis after vomiting in children with spinal muscular atrophy: A report of 9 patients

BackgroundSpinal muscular atrophy (SMA) is a hereditary neuromuscular disease that progresses toward restrictive respiratory failure due to muscle paralysis. We observed that SMA patients presented with a specific clinical and laboratory profile, consisting of severe metabolic acidosis following an episode of mild vomiting. This is an unusual, little-known, and life-threatening situation for these patients, as hyperventilation induced by metabolic acidosis can lead to exhaustion and to death by mixed acidosis. ObjectiveThe aim of our study was to describe this paradoxical acidosis after vomiting in SMA patients and to discuss the physiological basis of this condition. MethodsWe conducted a retrospective single-center study reviewing the clinical and laboratory data of SMA patients who were hospitalized in the intensive care unit for severe metabolic acidosis after vomiting. ResultsOur cohort comprised 11 cases. On arrival, the median pH of the patients was 7.23 with a median bicarbonate concentration of 11.7 mmol/L and almost half of them (45 %) had ketone bodies in the blood and/or urine. The median correction time was 24 h for pH and 48 h for bicarbonate concentrations after receiving intravenous hydration with a glucose solution. ConclusionsWe suggest that SMA patients are particularly sensitive to ketoacidosis induced by fasting, even after a few episodes of mild vomiting. Moreover, they have a low buffering capacity due to their severe amyotrophy, which favors metabolic acidosis. They must be quickly hydrated through a glucose-containing solution to avoid exhaustion, mixed acidosis, and death.

Characterization of two carbonic anhydrase isoforms in the pulmonate snail (Lymnaea Stagnalis) and their involvement in Molluskan calcification

Calcifying organisms are suffering from negative impacts induced by climate change, such as CO2-induced acidification, which may impair external calcified structures. Freshwater mollusks have the potential to suffer more from CO2-induced acidification than marine calcifiers due to the lower buffering capacity of many freshwater systems. One of the most important enzymes contributing to the biomineralization reaction is carbonic anhydrase (CA), which catalyzes the reversible conversion of CO2 to bicarbonate, the major carbon source of the calcareous structure in calcifiers. In this study we characterized two α-CA isoforms (LsCA1 and LsCA4) from the freshwater snail Lymnaea stagnalis using a combination of gene sequencing, gene expression, phylogenetic analysis and biochemical assays. Both CA isoforms demonstrated high expression levels in the mantle tissue, the major site for biomineralization. Furthermore, expression of LsCA4 during development parallels shell formation. The primary protein structure analysis, active site configuration and the catalytic activity of LsCA4 together suggest that the LsCA4 is embedded in the apical and basolateral membranes of mantle cells; while LsCA1 is proposed to be cytosolic and might play an important role in acid-base regulation. These findings of LsCA isoforms form a strong basis for a more detailed physiological understanding of the effects of elevated CO2 on calcification in freshwater mollusks.

Improving pH buffering capacity of an acid soil to regulate nutrient retention and mitigate water pollution using Calciprill and sodium silicate

In the tropics, high rainfalls and hot temperatures cause the formation of highly weathered acid soils with low pH buffering capacity (pHBC). Such soils are prone to nutrient losses via leaching, surface runoff, and volatilization. The poor nutrient retention of the highly weathered soils can cause environmental pollution in water bodies and detrimentally affect aquatic ecosystem. A preliminary study was conducted by mixing an acid soil (Bekenu series, Typic Paleudults) with Calciprill (80 %, 90 %, and 100 % Ca saturation) and sodium silicate (90, 105, 120, 135, and 150 kg ha−1) to determine the effects of the amendments on pH and pHBC of Bekenu series. Furthermore, a soil incubation study was carried out to determine the relationship between pH, pHBC, and effective cation exchange capacity (ECEC) after the soil was applied with Calciprill and sodium silicate and incubated for 40, 80, and 120 days. After the soil was harvested, the relationship between pHBC with soil exchangeable ammonium (NH4+), available nitrate (NO3-), and available phosphorus (P) to determine whether the combined use of Calciprill and sodium silicate is able to mitigate N and P losses through surface runoff and leaching to contaminate the surface and underground water bodies. The results from the studies showed that Calciprill and sodium silicate significantly increased soil pH and pHBC of Bekenu series. Notably, in the soil incubation study, the treatments with Calciprill and sodium silicate consistently improved pHBC compared with the soil without these amendments, suggesting that C2S4 (Calciprill at 90 % Ca saturation and sodium silicate at 135 kg ha−1) is the minimum amount of the amendments required to improve the pHBC of Bekenu series. The significant positive correlation between pH, pHBC, and ECEC throughout the soil incubation study indicates that the amendments are capable of improving pHBC of the Bekenu series when the pH and ECEC increase because of their alkalinity in addition to the presence of carbonate and silicate minerals. The significant positive correlations between pHBC with exchangeable NH4+ and available P at 40 and 80 DAI suggest that the Calciprill and sodium silicate can improve NH4+ and P availability for crop uptake. On the contrary, the significant negative correlation between pHBC and available NO3- at 80 DAI also suggests that the combined use of amendments can significantly reduce the NO3- contamination in water bodies because of improved pHBC. The most suitable combination for improving soil pH, ECEC, and pHBC is C2S4 (Calciprill at 90 % Ca saturation and sodium silicate at 135 kg ha−1) and it is possible to co-apply Calciprill and sodium silicate to mitigate NO3- contamination in water bodies. To further validate the findings of this study, greenhouse study is recommended to elucidate the plant-soil interactions.

Utilizing magnetic nanoparticles embedded into polyvinyl alcohol and sodium alginate for the absorption of arsenic

Arsenic is an extremely toxic metalloid. The majority of arsenic water pollution originates from industrial activities such as mining, smelting, and utilization of arsenic compounds in glass, pigment, semiconductor, and other industries. Arsenic-containing wastewater poses a threat to groundwater, freshwater, seawater, and soil. Bioaccumulation of arsenic as a result of accidental ingestion may have a harmful effect on the skin and cardiovascular, respiratory, and nervous systems, thereby posing a major health risk. Chemical coagulation, membrane filtration, and adsorption can be used to treat arsenic-containing wastewater. However, chemical coagulation produces a large amount of waste sludge, which is harmful and incurs high processing costs. Membrane filtration is difficult to adopt because of its high operation and maintenance costs. Adsorption is an inexpensive, easy-to-use, sludge-free water treatment method that enables adsorbent recycling. These characteristics make adsorption an economically feasible technique for water treatment. Magnetic nanoparticles (MNPs) are small particles with a high surface area to volume ratio. Their strong magnetic properties enable them to absorb specific water pollutants. MNPs are currently used as water treatment adsorbents. However, they have several drawbacks, including low acid and alkali buffer capacity and water oxidation. In this study, MNPs immobilized with polyvinyl alcohol (PVA) and sodium alginate (SA) were used to enhance the efficacy of wastewater treatment with magnetic materials. These modified MNPs exhibited magnetic characteristics and improved acid resistance. When 100 g/L PVA/SA-MNPs (pH 1–6) were stirred at 120 rpm for 30 min, the resulting iron concentration of the water was 16 mg/L. By contrast, the MNPs released iron in levels ranging from 18 to 4045 mg/L. The PVA/SA–MNPs efficiently adsorbed arsenic in the pH range 3–6, with a high removal efficiency of 76%–82%. At pH 5, the average adsorption capacity was 382 ± 27 μg/g. To recover the MNPs, they were rinsed with deionized water and immersed in acid three times, after which their adsorption capacity was 300 μg/g or higher. By contrast, the PVA/SA-MNPs could be recovered through spontaneous sedimentation, eliminating the need for a magnetic field and simplifying the collection process. In addition, iron dissolution in acidic solutions was minimized for the PVA/SA-MNPs, contributing to environmental protection.

Optimizing Cardioplegic Solutions: A Focus on Pharmaco-Cold Strategies

This study investigates the impact of crystalloid cardioplegic solutions (CCS) on electrophysiological mechanisms and the contractile system during the diastolic phase. Extracellular solutions, categorized by ion concentration, demonstrate efficacy in inducing cardiac arrest through moderately elevated potassium or potassium-magnesium combinations, aligning with normal or slightly reduced sodium and calcium levels. Notably, the ease of equilibration with myocardial tissue enhances the protective effect, correlating with infusion volume and duration of action. However, drawbacks such as low buffering capacity and the need for reinfusion after 15-20 minutes are identified. This research sheds light on the dynamic relationship between solution composition, duration of action, and protective efficacy, providing valuable insights for refining cardioplegic protocols in cardiac surgeries. Highlights: Intracellular vs. Extracellular Impact: Explore ion concentration's influence on crystalloid cardioplegic solutions, emphasizing the choice between intracellular and extracellular formulations. Equilibration Dynamics: Investigate the direct correlation between infusion volume, duration of action, and the protective effect, emphasizing equilibration with myocardial tissue. Refining Cardioplegic Protocols: Identify limitations like low buffering capacity, necessitating reinfusion, and offer insights into strategies for enhancing cardioplegic protocols in cardiac surgeries. Keywords: Cardioplegia, Intracellular Solutions, Calcium paradox, Protective Efficacy, Cellular Metabolism

Biotesting for adsorptive bioremediation of oil-contaminated podzolic soil in Western Siberia

The majority of Russia’s oil and gas-producing regions are situated in the northern part of Western Siberia, where sandy podzolic soils are prevalent. Due to the low buffering capacity of these soils and the severe Arctic climate, the conventional method of bioremediation for removing oil contamination is not effective. This study, for the first time, explores the potential of adsorptive bioremediation for purifying oil-polluted gley-podzolic soil. This approach involves introducing natural sorbents of various classes before soil treatment through bioremediation. The optimal conditions for soil treatment can be determined using the express phytotests based on white clover ( Trifolium repens ) seed germination. The results indicate that under the best conditions, which involve adding 2 % mixed sorbent based on granulated activated carbon (GAC) and diatomite (4:1) or Spilsorb, it is possible to minimize soil phytotoxicity after 2-3 warm seasons and reduce the content of total petroleum hydrocarbons to the permissible residual oil content (≤5 g/kg) established in the territory of the Khanty-Mansiysk Autonomous Okrug for recultivated agricultural soils. Moreover, other sorbents, such as peat, GAC, vermiculite, zeolite, and diatomite, can be used to reduce phytotoxicity to &lt;33 %, allowing for additional soil decontamination through phytoremediation.

Ultrastructure of neuron-glia interaction in the norm and experimental pathology

Long-term experience was gained in analyzing synapses and their glial surroundings in normal, natural, and experimental models of functional plasticity and brain pathology development. However, most studies in this area rely on electrophysiological techniques combined with fluorescent imaging. Notably, fine synapse structure and astrocytic processes cannot be resolved using light or some electron microscopy techniques. Studies on experimental brain pathology using volume electron microscopy methods [1] were previously restricted due to their high labor intensity. However, automated methods for sample preparation and analysis, using machine vision and artificial intelligence, significantly simplified this task. Using transmission electron microscopy methods and 3D reconstructions, this study examined the Str. radiatum CA1 hippocampal region of rat brains in a chronic lithium-pilocarpine model of epilepsy. The results indicate a decrease in synaptic number along with an increase in their size and a reduction in astrocytic isolation of the active zones. A decrease in glial ensheathment of enlarged active zones and facilitation of neurotransmitter diffusion to active synapses may have a multiplicative effect on epileptiform activity growth and excitotoxicity. The simplification of the astrocytes meshwork in the somatosensory cortex’s layer 2/3 is comparable to that of layer 1. This decrease in layer 1’s inhibitory action enables pyramidal neurons in layer 2/3 to potentially exhibit epileptiform activity. Thus, the superficial cortical layers’ structural-functional aspects can be used as a natural cellular model in epilepsy development studies. Reduction of Ca2+ events in astrocyte processes in lithium-pilocarpine induced epilepsy may result from the low buffer capacity of Ca2+ ions in the smooth endoplasmic reticulum (sER) and/or impaired Ca2+ wave transmission through the gap junctions between astrocytic processes. High resolution is necessary to analyze the gap junctions, and special methods are required for sER visualization in perisynaptic astrocytic processes. We developed original sER staining methods [2] to quantitatively evaluate gap junctions and sER cisternae within astrocytic meshworks in layers 1 and 2/3 of the somatosensory cortex. In layer 1, the area of gap junctions in relation to the volume of an astrocyte was twice as high as in layer 2/3. The proportion of sER volume differed between layer 1 and layer 2/3 tissues. Specifically, the total sER cisternae volume in layer 2/3 was twice as high as in layer 1, relative to the volume of astrocytic processes [3]. Additionally, a doubling of single astrocytic gap junction area concomitant with decreased calcium events was observed. The results suggest a normal balance between Ca2+ stores (sER) and gap junctions, whose disruption may contribute to the development of seizures.

Sustainable in situ ammonia recovery from municipal solid waste leachate in a single-stream microbial desalination cell

Municipal solid waste (MSW) leachate is one of the most hazardous waste streams leading to great potential risk to environment, and a renewable resource with high concentrations of organic contaminant and ammonia. High energy consumption and chemical input are still the challenges for ammonia recovery from MSW leachate. Here, a single-stream microbial desalination cell (SMDC) was successfully developed for simultaneous energy extraction from organic contaminant and in-situ energy utilization for ammonia recovery. 70% of the organic contaminant from the actual MSW leachate was removed, and 24.9% of the total ammonia was recovered as high-purity (NH4)2SO4. The additional desalination chamber introduced into the SMDC can potentially enhance the NH4+ migration that was determined by the NH4+ concentration gradient and electric field. More than 30% of the total nitrogen was lost, as revealed by nitrogen mass balance analysis, probably resulting from the anodic denitrification process driven by denitrifying microorganisms, e.g., Thauera, which thrived in the anode chamber. Concomitantly, the chemical input for ammonia stripping can be reduced by up to 68% due to the relatively low buffer capacity of the catholyte and the OH− production from the cathode reaction. This SMDC can be an effective and environmentally sustainable solution for MSW leachate treatment and resource recovery.

Does Media Choice Matter When Evaluating the Performance of Hydroxypropyl Methylcellulose Acetate Succinate-Based Amorphous Solid Dispersions?

Hydroxypropyl methylcellulose acetate succinate (HPMCAS) is a weakly acidic polymer that is widely used in the formulation of amorphous solid dispersions (ASDs). While the pH-dependent solubility of HPMCAS is widely recognized, the role of other solution properties, including buffer capacity, is less well understood in the context of ASD dissolution. The goal of this study was to elucidate the rate-limiting steps for drug and HPMCAS release from ASDs formulated with two poorly water soluble model drugs, indomethacin and indomethacin methyl ester. The surface area normalized release rate of the drug and/or polymer in a variety of media was determined. The HPMCAS gel layer apparent pH was determined by incorporating pH sensitive dyes into the polymer matrix. Water uptake extent and rate into the ASDs were measured gravimetrically. For neat HPMCAS, the rate-limiting step for polymer dissolution was observed to be the polymer solubility at the polymer-solution interface. This, in turn, was impacted by the gel layer pH which was found to be substantially lower than the bulk solution pH, varying with medium buffer capacity. For the ASDs, the HPMCAS release rate was found to control the drug release rate. However, both drugs reduced the polymer release rate with indomethacin methyl ester having a larger impact. In low buffer capacity media, the presence of the drug had less impact on release rates when compared to observations in higher strength buffers, suggesting changes in the rate-limiting steps for HPMCAS dissolution. The observations made in this study can contribute to the fundamental understanding of acidic polymer dissolution in the presence and absence of a molecularly dispersed lipophilic drug and will help aid in the design of more in vivo relevant release testing experiments.

Accumulation of Lead and Nutrients in Soybean and Sorghum Cultivated in Lead-Affected Tropical Soils

ABSTRACT Lead is a potentially toxic chemical element, being responsible for many deleterious effects in living organisms. Therefore, understanding its dynamics and influence on plant growth is relevant for food security. The influence of Pb doses on nutrient accumulation in sorghum and soybean in two tropical soils with different buffering capacities was tested in a greenhouse study with four independent experiments (one per species/soil combination). The hypothesis was that the presence of Pb in soil decreases the accumulation of nutrients in soybean and sorghum plants. Soybean cultivated in a Typic Hapludox (TH) and sorghum, cultivated in both a Rhodic Acrudox (RA) and a TH, received 0, 200, 400, 800, 1200, 1600, 2200, and 2800 mg/kg of Pb, while soybean cultivated in RA received 0, 200, 400, 800, and 1600 mg/kg of Pb. Seeds were sown 24 h after application of Pb. Plants were harvested 21 days after the emergence of at least 50% of plants from the control treatment (approximately 30 days in total). Lead, macro, and micronutrient contents were determined in the shoot dry matter (SDM), and bioavailable Pb in soil was assessed by Mehlich-1. In general, TH allowed greater Pb uptake by plants, due to its lower buffering capacity. Soybean was the most affected crop with decreasing concentrations of N, K, Mg, and Ca, the latter was especially affected, with deficiency symptoms being observed. Effects on a longer time-scale are unknown, since significant decreases in nutrient contents were observed.

The Influence of Electrokinetic Remediation Process on the Removal of Cationic and Anionic Dyes from Kaolinitic Soils

Low permeability soils possess specific mineralogical properties such as particle size, high buffer capacity, and high sorption capacity, which make them difficult to remediate and so pose serious environmental problems when polluted. The grain pores of these low permeability so ils trap in pollutants tightly, which are inaccessible and non-responsive to traditional technologies during remediation. Traditional technologies, some of which are ex-situ remediation techniques further compound these environmental problems through logistics and economic infeasibility. Electrokinetic Remediation (EKR) can offer certain advantages for treatment of various contaminants which include organic compounds, heavy metals, radionuclides, organic waste and some mixed inorganic species from a matrix with high salinity, low permeability and high buffering capacity. In addition, (EKR) is a clean and novel technique which accesses the grain pores of low permeability soils such as clays and silts, which have proven non-responsive to other soil remediation technologies such as soil flushing and soil washing. Among these fine soils, it has been proven that (EKR) is more effective on clay soil with particle size &lt;2mm, moderate plasticity, lower cation exchange capacity (CEC) and lower buffering capacity which can be found in this order: kaolinite&gt;illinite &gt;bentonite.

A Comparative Evaluation of Physical Parameters of Saliva and Correlation with Periodontal Condition in Down Syndrome Children and Healthy Controls.

The aim of this study was to assess the significance and role of physical parameters of saliva on periodontal health in children with Down syndrome (DS). A comparative evaluation of physical parameters of saliva such as flow rate, viscosity, pH, quantity and buffering capacity, and buffer capacity was carried out using GC Saliva-Check Buffer kit and correlated with periodontal condition examined using community periodontal index of treatment needs (CPITN) in 40 DS subjects (group I) and 40 healthy controls (group II) aged 8-15 years. Down syndrome subjects had a low resting salivary flow rate, moderately acidic saliva, very low quantity of stimulated saliva, and low buffering capacity. On correlating salivary parameters with the periodontal condition, DS subjects with CPITN code 1 had low resting salivary flow rate, normal viscosity, moderately acidic pH, very low quantity of stimulated saliva, and low buffering capacity. Down syndrome subjects with CPITN code 2 had low resting flow rate, increased viscosity, very low quantity of stimulated saliva, low buffering capacity, and moderately acidic pH. Healthy controls with CPITN code 0 had normal resting flow rate, viscosity of saliva, quantity of stimulated saliva, buffering capacity, and moderately acidic pH. Compared to healthy controls, DS subjects showed decreased values for resting flow rate, pH, quantity of stimulated saliva, and buffering capacity. A statistically significant correlation was observed between the physical parameters of saliva and periodontal condition in DS subjects (p < 0.05). Periodontal diseases start at a very early age and periodontal health deteriorates at a faster rate in DS children for which saliva also plays its part. Prime importance should be given to frequent oral hygiene and preventive measures in DS children thus preventing accumulation of debris and plaque.

Biogeochemical Processes and Microbial Dynamics Governing Phosphorus Retention and Release in Sediments: A Case Study in Lower Great Lakes Headwaters.

The ability of headwater bed and suspended sediments to mitigate non-point agricultural phosphorus (P) loads to the lower Great Lakes is recognized, but the specific biogeochemical processes promoting sediment P retention or internal P release remain poorly understood. To elucidate these mechanisms, three headwater segments located within priority watersheds of Southern Ontario, Canada, were sampled through the growing season of 2018-2020. The study employed equilibrium P assays along with novel assessments of legacy watershed nutrients, nitrogen (N) concentrations, sediment redox, and microbial community composition. 20-year data revealed elevated total P (TP) and total Nitrogen (TN) at an inorganic fertilizer and manure fertilizer-impacted site, respectively. Overall, sampled sites acted as P sinks; however, agricultural sediments exhibited significantly lower buffering capacity compared to a reference forested watershed. Collection of fine suspended sediment (<63 µm) through time-integrated sampling showed the suspended load at the inorganic-fertilized site was saturated with P, indicating a greater potential for P release into surface waters compared to bed sediments. Through vertical microsensor profiling and DNA sequencing of the sediment microbial community, site-specific factors associated with a distinct P-source event were identified. These included rapid depletion of dissolved oxygen (DO) across the sediment water interface (SWI), as well as the presence of nitrate-reducing bacterial and ammonia-oxidizing archaeal (AOA) genera. This research provides valuable insights into the dynamics of P in headwaters, shedding light on P retention and release. Understanding these processes is crucial for effective management strategies aimed at mitigating P pollution to the lower Great Lakes.

Accurate computation of desalinated seawater re-mineralization processes using blending with surface water, chemicals dosing and minerals dissolution

Desalinated seawater often represents lack of merit nutrients, unstable and low buffer capacity owing to the fact that various aqueous ions are almost removed. The various re-mineralization processes, such as blending with surface water, chemicals dosing, and minerals dissolution, are commonly used for introduction of merit ions and carbonate alkalinity to desalinated seawater to meet health requirement and to protect water supply facilities from corrosion. This paper discusses the optimization of various re-mineralization processes based on accurate model computation with emphasis on carbonate system model, water stability index, blending model, and mineral surface dissolution model. The accurate model computation investigation justifies the efforts and costs through various re-mineralization processes for achieving narrow water quality criteria.

Salivary Buffering Capacity, Flow Rate and Calcium Levels in Children with and without Early Childhood Caries – a Comparative Study

Background: Early Childhood Caries (ECC) is a phenomenon that affects primary teeth in children below 6 years of age. Its severity could have a far-reaching impact on children with resultant effects on their quality of life. An assessment of a child's caries risk using saliva is a valuable non-invasive diagnostic tool utilised in preventing or reducing the impact of this condition.&#x0D; Objective: To assess the buffering capacity, flow rate and calcium levels of saliva in children and their association with ECC.&#x0D; Methodology: The study consisted of fifty (50) subjects aged 45 to 71 months recruited from Lagos University Teaching Hospital (LUTH) and staff primary school, Idi-Araba. Unstimulated saliva collected between 9 – 11 am was used to evaluate saliva's buffering capacity, flow rate and calcium levels in children with and without ECC.&#x0D; Results: The subjects were aged below 71 months (with a mean age of 56.66 ± 7.17 months). A major proportion (67.0%) of the component of the dmft was cavitated lesion related. The caries-free subjects had slightly higher mean rank values in salivary flow rate (MR = 27.52, U = 262, p = 0.325), slightly lower mean rank values in calcium level (MR = 24.64, U = 291, p = 0.677) and lower buffering capacity values than caries active subjects.&#x0D; Conclusion: The properties of saliva such as buffering capacity, flow rate and calcium level were not significantly different between the study groups. Therefore, there is no association between buffering capacity, flow rate, calcium level, and ECC. This implies that more investigations are required to evaluate the protective effects of other salivary physiochemical factors like antioxidants, other than those investigated in this study.&#x0D; &#x0D;

Consequences of elevated CO2 on soil acidification, cation depletion, and inorganic carbon: A column-based experimental investigation

The anthropogenic release of atmospheric CO2 affects soil nutrient cycling through varied biogeochemical processes. Cation depletion from exchange sites, carbonate mineral dissolution, and subsequent changes in organic and inorganic carbon flux are growing concerns for soil health and sustainability. Particularly, the effects of acid deposition on soil pH and soil health under changing global carbon flux is poorly understood. To estimate the magnitude and effects of pH change across different soil profiles, the depth-wise response of soil cations, pH, and soil inorganic carbon (SIC) to varying CO2 levels was investigated using column-leachate experiments. Six soils, representing acidic, neutral, and alkaline pH, were exposed to different CO2 enrichments (100%, 10%, 1%, and Control) of water percolate for 30 days. Analysis of the column leachates revealed that the base cations (Ca, Mg, Na) were higher initially than on day 30, while Si leaching increased with time. The pH in leachates tended to attain an equilibrium state with time under CO2 saturation, indicating the buffering capacity of alkaline and neutral soils. Evaluation of the soil before and after the experiments showed that the solid SIC, such as carbonate minerals and any dissolved SIC components (e.g., carbonate, bicarbonate ions) entrained in the pore space increased, whereas the potential cation exchange capacity (PCEC) decreased in all soils. This trend was especially prominent for alkaline soils at 100% CO2 enrichment. Over the short-term study, the SIC showed minimal response to varying CO2 enrichment conditions in neutral and acidic soils. The altered cation concentrations in the leachates suggest that under long-term exposure to elevated CO2, a deficiency of cationic essential plant nutrients such as Ca2+, Mg2+, and K+ is likely, especially with low buffering capacity and primary mineral content. In contrast, an increase in nutrient solubility and elemental toxicity (e.g., Al3+ Mn) can be observed in the short term. The initial soils with greater ECEC experienced an increased SIC leaching in the shorter term and suggested potential deposition in deeper layers. The resultant SIC loss might be amplified in arid to semi-arid soils with low SIC and affect soil health.

Reliable Cerebrospinal Fluid Cytology and Immunocytochemistry Reporting over an Extended Period by the Addition of Aldehyde and Osmolyte-Based Preservative Solution

Introduction: The cytological examination of cerebrospinal fluid (CSF) is an important investigation in the workup of various inflammatory, malignant, or traumatic disorders of the central nervous system. The cells in the CSF lyse and degenerate at a very fast rate owing to its low tonicity, buffering capacity, redox potential, and pH, making it crucial to examine it within 2 h of sampling. We have hereby designed an aliphatic aldehyde, osmolyte, metal halide, and a buffer-based solution which will preserve the cellular components of CSF for 48 h. Methods: Thirty-nine CSF specimens were examined within 2 h of collection, and this reading was recorded as time zero reading. The CSF specimens were then divided into two tubes with (i) pre‐servative:CSF ratio of 1:5; and (ii) no preservative. Total and differential leukocyte counts and immunocytochemistry were performed on the paired specimens at 24 h and 48 h and were compared with the readings at zero hours. Results: The preservative-containing CSF showed significantly higher cellularity than the undiluted samples at 24 h and 48 h (p < 0.001). Median cell counts observed in the preservative-containing CSF were 5 times and 12 times higher than in the undiluted CSF. Neutrophils, lymphocytes, and RBCs showed immunopositivity for MPO, CD45, and GLUT-1 at both time intervals. Conclusion: Adding the prepared preservative solution to CSF in the ratio of 1:5 can optimally preserve the CSF cells for absolute and differential quantitation, morphological assessment, and immunological testing at a later date.

High buffering capacity cobalt-doped nickel hydroxide electrode as redox mediator for flexible hydrogen evolution by two-step water electrolysis

Two-step water electrolysis has been proposed to tackle the ticklish H2/O2 mixture problems in conventional alkaline water electrolysis recently. However, low buffering capacity of pure nickel hydroxide electrode as redox mediator limited practical application of two-step water electrolysis system. A high-capacity redox mediator (RM) is urgently needed to permit consecutive operation of two-step cycles and high-efficiency hydrogen evolution. Consequently, a high mass-loading cobalt-doped nickel hydroxide/active carbon cloth (NiCo-LDH/ACC) RM is synthesized via a facile electrochemical method. The proper Co doping can apparently enhance the conductivity and simultaneously remain the high-capacity of the electrode. Density functional theory results further confirms more negative values in redox potential of NiCo-LDH/ACC than Ni(OH)2/ACC on account of the charge redistribution induced by Co doping, which can prevent the parasitic O2 evolution on RM electrode during decoupled H2 evolution step. As a result, the NiCo-LDH/ACC combined the superiorities of high-capacity Ni(OH)2/ACC and high-conductivity Co(OH)2/ACC, and the NiCo-LDH/ACC with 4:1 ratio of Ni to Co presented a large specific capacitance of 33.52F/cm2 for reversible charge–discharge and high buffering capacity with two-step H2/O2 evolution duration of 1740 s at 10 mA/cm2. The necessary input voltage (2.00 V) of the whole water electrolysis was broken into two smaller ones, 1.41 and 0.38 V, for H2 and O2 production, respectively. NiCo-LDH/ACC provided a favorable electrode material for the practical application of two-step water electrolysis system.

Effect of calcareous and siliceous amendments on N2O emissions of a grassland soil

AbstractLiming of acidic agricultural soils has been proposed as a strategy to mitigate nitrous oxide (N2O) emissions, as increased soil pH reduces the N2O/N2 product ratio of denitrification. The capacity of different calcareous (calcite and dolomite) and siliceous minerals to increase soil pH and reduce N2O emissions was assessed in a 2‐year grassland field experiment. An associated pot experiment was conducted using homogenized field soils for controlling spatial soil variability. Nitrous oxide emissions were highly episodic with emission peaks in response to freezing–thawing and application of NPK fertilizer. Liming with dolomite caused a pH increase from 5.1 to 6.2 and reduced N2O emissions by 30% and 60% after application of NPK fertilizer and freezing–thawing events, respectively. Over the course of the 2‐year field trial, N2O emissions were significantly lower in dolomite‐limed than non‐limed soil (p &lt; .05), although this effect was variable over time. Unexpectedly, no significant reduction of N2O emission was found in the calcite treatment, despite the largest pH increase in all tested minerals. We tentatively attribute this to increased N2O production by overall increase in nitrogen turnover rates (both nitrification and denitrification) following rapid pH increase in the first year after liming. Siliceous materials showed little pH effect and had no significant effect on N2O emissions probably because of their lower buffering capacity and lower cation content. In the pot experiment using soils taken from the field plots 3 years after liming and exposing them to natural freezing–thawing, both calcite (p &lt; .01) and dolomite (p &lt; .05) significantly reduced cumulative N2O emission by 50% and 30%, respectively, relative to the non‐limed control. These results demonstrate that the overall effect of liming is to reduce N2O emission, although high lime doses may lead to a transiently enhanced emission.