Ion Signal Research Articles

Rapid Quantification of Neuraminidase Activity by MALDI-TOF MS via On-Target Labeling of Its Substrate and Product.

Neuraminidase (NA) is a kind of glycoside hydrolase enzyme, functioning to remove terminal sialic acid (Sia) from glycans which are located on the cell surface. NA plays an essential role in cell interactions with ligands, microbes, and other cells during physiological and pathological processes. Additionally, NA is a major target for developing anti-influenza drugs and influenza vaccines. Herein, a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) based method to quantify NA activity is demonstrated for the first time. A reactive matrix 2-hydrazinoquinoline (2-HQ) is used to on-target label the natural substrate (3-sialyllactose, 3'-SL) and its enzymatic product (Sia). The derivatization enhances the ionization efficiency of 3'-SL and Sia, especially in negative ion detection mode. Moreover, the lactose ion signals and noise are significantly suppressed. Consequently, NA activity in influenza vaccines has been successfully quantified by comparing the relative intensity of 2-HQ derivatized Sia and 3'-SL in the absence of an additional internal standard. Moreover, the inhibition efficiencies of NA inhibitors have also been measured. Due to its operating simplicity, high-throughput capacity, and quantification accuracy, the proposed method has potential to be applied for the detection of different kinds of NA activity to reveal the role of NA in immunity, vaccine, and infection processes.

Use of Resonant Acoustic Fields as Atmospheric-Pressure Ion Gates.

Ion optics are crucial for spectrometric methods such as mass spectrometry (MS) and ion mobility spectrometry (IMS). Among the wide selection of ion optics, temporal ion gates are of particular importance for time-of-flight MS (TOF-MS) and drift-tube IMS. Commonly implemented as electrostatic ion gates, these optics offer a rapid, efficient means to block ion beams and form discrete ion packets for subsequent analysis. Unfortunately, these devices rely on pulsed high voltage sources and are not fully transparent, even in their open state, which can lead to ion losses and contamination. Here, a novel atmospheric-pressure ion gate based on a resonant acoustic field structure is described. This effect was accomplished through the formation of a resonant, standing acoustic wave of alternating nodes and antinodes. Alignment of an atmospheric-pressure gaseous ion beam with an antinode, i.e. a region of transient pressure, of the acoustic structure acted as a gate and blocked ions from impinging on ion-selective detectors, such as a mass spectrometer and a Faraday plate. The velocity of the ion stream and acoustic power were found to be critical parameters for gating efficiency. In the presence of an acoustic field (i.e., a closed gate), ion signals decreased by as much as 99.8% with a response time faster than the readout of the ion-measurement devices used here (ca. 75 ms). This work demonstrates the basis for a low-cost, acoustic ion gate, which is optically transparent and easily constructed with low-power, off-the-shelf components, that could potentially be used with MS and IMS instrumentation.

The Multiferroic, Magnetic Exchange Bias Effect, and Photodetection Multifunction Characteristics in MnSe/Ga0.6Fe1.4O3 Heterostructure

Artificial heterostructures are typically created by layering distinct materials, thereby giving rise to unique characteristics different from their individual components. Herein, two-dimensional α-MnSe nanosheets with a non-layered structure were fabricated on Ga0.6Fe1.4O3 (GFO) films. The superior crystalline properties of MnSe/GFO heterostructures were confirmed through structural and morphological analyses. The remanent polarization is around 1.5 μC/cm2 and the leakage current density can reach 2 × 10−3 A/cm2 under 4 V. In addition, the piezo-response force microscopy amplitude and phase images further supported the ferroelectric property. The significant improvement of coercive field and saturated magnetization, along with the antiparallel signals of Mn and Fe ions observed through synchrotron X-ray analyses, suggest the presence of magnetic interaction within the MnSe/GFO heterostructure. Finally, the excellent photodetector with a photo detectivity of 6.3 × 108 Jones and a photoresponsivity of 2.8 × 10−3 A·W−1 was obtained under 532 nm in the MnSe/GFO heterostructure. The characteristics of this heterostructure, which include multiferroic, magnetic exchange bias effect, and photodetection capabilities, are highly beneficial for multifunctional devices.

Deciphering the role of metal ion transport-related genes in T2D pathogenesis and immune cell infiltration via scRNA-seq and machine learning

IntroductionType 2 diabetes (T2D) is a complex metabolic disorder with significant global health implications. Understanding the molecular mechanisms underlying T2D is crucial for developing effective therapeutic strategies. This study employs single-cell RNA sequencing (scRNA-seq) and machine learning to explore the the pathogenesis of T2D, with a particular focus on immune cell infiltration.MethodsWe analyzed scRNA-seq data from islet cells of T2D and nondiabetic (ND) patients, identifying differentially expressed genes (DEGs), especially those related to metal ion transport (RMITRGs). We employed 12 machine learning algorithms to develop predictive models and assessed immune cell infiltration using single-sample gene set enrichment analysis (ssGSEA). Correlations between immune cells and key RMITRGs were investigated, and the interactions among these genes were explored through protein-protein interaction (PPI) network analysis. Additionally, we performed a detailed cell-cell communication analysis to identify significant signaling pathways in T2D.ResultsOur analysis identified 1953 DEGs between T2D and ND patients, with the Stepglm[backward] plus GBM model demonstrating high predictive accuracy and identifying 13 hub RMITRGs. Twelve protein structures were predicted using AlphaFold 3, revealing potential functional conformations. We observed a strong correlation between hub RMITRGs and immune cells, and PPI network analysis revealed key interactions. Cell-cell communication analysis highlighted 16 active signaling pathways, with CXCL, MIF, and COMPLEMENT linked to immune and inflammatory responses, and WNT, KIT, LIFR, and HGF pathways uniquely activated in T2D.ConclusionOur analysis identified genes crucial for T2D, emphasizing ion transport, signaling, and immune cell interactions. These findings suggest therapeutic potential to enhance T2D management. The identified pathways and genes provide valuable insights into the disease mechanisms and potential targets for intervention.

Metal Ion Signaling in Biomedicine.

Complex multicellular organisms are composed of distinct tissues involving specialized cells that can perform specific functions, making such life forms possible. Species are defined by their genomes, and differences between individuals within a given species directly result from variations in their genetic codes. While genetic alterations can give rise to disease-causing acquisitions of distinct cell identities, it is now well-established that biochemical imbalances within a cell can also lead to cellular dysfunction and diseases. Specifically, nongenetic chemical events orchestrate cell metabolism and transcriptional programs that govern functional cell identity. Thus, imbalances in cell signaling, which broadly defines the conversion of extracellular signals into intracellular biochemical changes, can also contribute to the acquisition of diseased cell states. Metal ions exhibit unique chemical properties that can be exploited by the cell. For instance, metal ions maintain the ionic balance within the cell, coordinate amino acid residues or nucleobases altering folding and function of biomolecules, or directly catalyze specific chemical reactions. Thus, metals are essential cell signaling effectors in normal physiology and disease. Deciphering metal ion signaling is a challenging endeavor that can illuminate pathways to be targeted for therapeutic intervention. Here, we review key cellular processes where metal ions play essential roles and describe how targeting metal ion signaling pathways has been instrumental to dissecting the biochemistry of the cell and how this has led to the development of effective therapeutic strategies.

Validation and the role of PDK4 relevant to ferroptosis in degenerative lumbar disc disease

BackgroundFerroptosis was involved in the pathogenesis of intervertebral disc degeneration (IVDD). However, the exact mechanism of IVDD associated with ferroptosis still required deeper studies.MethodThe differentially expressed genes (DEGs) in rat lumbar disc tissue between the control and IVDD group treated with IL-1β were detected by RNA sequencing (RNA-seq). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on DEGs. We further screened the differential expressed ferroptosis-related genes (DEFRGs). Besides, a protein-protein interaction (PPI) network of DEFRGs was constructed by STRING database. The Cytoscape database identified significant modules and the hub genes. The loss function of PDK4 by siRNA inference was investigated in NPCs by CCK8 assay, ELISA assay, and the analysis of ferroptosis indicators.ResultDEGs were identified using RNA-seq. KEGG pathway analysis showed that these genes were mainly involved in Parkinson’s disease, oxytocin signaling pathway, calcium ion signaling pathway, AMPK signaling pathway, and glucagon signaling pathway. Eight hub genes (including LDHA, PKM, EP300, EGFR, EGLN1, SCD, PDK4, and FABP4) were found by the PPI network and Cytoscape on a total of 25 ferroptosis-related genes that were identified in rat lumbar disc tissue after IVDD treatment. PDK4 silencing promoted NPCS proliferation, decreased the levels of the proinflammatory factors, and suppressed ferroptosis.ConclusionThe study suggested the potential roles of ferroptosis-related genes in IVDD and further revealed the role of PDK4 in the progression of IVDD.

Standardized workflow for multiplexed charge detection mass spectrometry on orbitrap analyzers.

Individual ion mass spectrometry (I2MS) is the Orbitrap-based extension of the niche mass spectrometry technique known as charge detection mass spectrometry (CDMS). While traditional CDMS analysis is performed on in-house-built instruments such as the electrostatic linear ion trap, I2MS extends CDMS analysis to Orbitrap analyzers, allowing charge detection analysis to be available to the scientific community at large. I2MS simultaneously measures the mass-to-charge ratios (m/z) and charges (z) of hundreds to thousands of individual ions within one acquisition event, creating a spectral output directly into the mass domain without the need for further spectral deconvolution. A mass distribution or 'profile' can be created for any desired sample regardless of composition or heterogeneity. To assist in reducing I2MS analysis to practice, we developed this workflow for data acquisition and subsequent data analysis, which includes (i) protein sample preparation, (ii) attenuation of ion signals to obtain individual ions, (iii) the creation of a charge-calibration curve from standard proteins with known charge states and finally (iv) producing a meaningful mass spectral output from a complex or unknown sample by using the STORIboard software. This protocol is suitable for users with prior experience in mass spectrometry and bioanalytical chemistry. First, the analysis of protein standards in native and denaturing mode is presented, setting the foundation for the analysis of complex mixtures that are intractable via traditional mass spectrometry techniques. Examples of complex mixtures included here demonstrate the relevant analysis of an intact human monoclonal antibody and its intricate glycosylation patterns.

Quantitative sizing of microplastics up to 20 µm using ICP-TOFMS.

A fundamental study of four different sample introduction systems was carried out to evaluate the upper size limit of microplastics measured by inductively coupled plasma-time-of-flight-mass spectrometry (ICP-TOFMS). Three different, certified microplastic samples (PS, PMMA and PVC) within a size range of 3-20 µm in suspension were measured. In this study, no particles larger than 10 µm could be detected using pneumatic nebulization for sample introduction. However, we were able to extend the upper size limit to 20 µm by either using a falling-tube device or a vertical downwards-pointing ICP-TOFMS. Particle transport efficiencies could only be estimated and were within a range of 13% to 184%. The particle size was quantified by using dissolved citric acid (non-matrix matched) and agreed with reference values. The critical size values were 2.3 µm for PS, 2.4 µm for PMMA and 3.0 µm for PVC. Additionally, in the case of PVC, chlorine could also be detected and the critical size value was 3.9 µm based on the 35Cl+ ion signal.

Integrated Network Pharmacology and In-silico Approaches to Decipher the Pharmacological Mechanism of Dioscorea septemloba Thunb in Treating Gout and Its Complications

Background: Dioscorea septemloba Thunb. (DST) has demonstrated therapeutic potential in the treatment of gout and its associated complications. However, the underlying mechanisms of DST’s pharmacological activity remain unclear. This study aims to investigate the pharmacological substances and network regulatory mechanisms of DST in treating gout and its complications using network pharmacology. Methods: According to ultra-high performance liquid chromatography coupled with hybrid quadrupole-Orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap-MS) data and Lipinski’s rule of five, 24 bioactive phytochemicals from DST were identified. The targets of gout were retrieved from Gene Expression Omnibus (GEO), GeneCards, and DisGeNET databases, followed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG pathway) enrichment analysis. The Cytoscape network analysis was used to identify the primary pathological pathways and key targets. Finally, LeDock was used for molecular docking to verify the active components of DST and their core target proteins. Results: DST contains several core active ingredients, such as tetrahydroimidazo[1,2-a]pyridine- 2,5-dione, diosgenin, beta-sitosterol, dioscorol B, montroumarin and 9,10-dihydro-5,7- dimethoxy-3,4-phenanthrenediol. Moreover, these active components were found to strongly bind to the key targets for treating gout and its complications, including HSP90AA1, STAT3, PTGS2, PPARG, MTOR, HIF1A, MMP9, ESR1, and TLR4. As a result, DST alleviates gout and its complications by inhibiting xanthine dehydrogenase (XDH) to reduce uric acid levels and regulating the HIF-1α, EZH2/STAT3, and COX-2/PPAR-γ pathways to reduce inflammation. Additionally, it also plays an analgesic role by regulating the neuroactive ligand-receptor interaction pathway and calcium ion signaling pathway. Conclusion: This study has provided insights into the underlying mechanisms of DST in the treatment of gout and its complications, which could serve as a scientific foundation for its clinical translation.

Enhancing mass analysis of ultra-high molecular weight polystyrene: a comparative study of copper and silver salts with MALDI mass spectrometry.

This study presents a report on the use of copper (Cu) salts in polymer mass spectrometry for samples exceeding several thousand daltons, demonstrating their efficiency and cost-effectiveness for analyzing ultra-high molecular weight (UHMW) polystyrene (PS). Using matrix-assisted laser desorption/ionization (MALDI) coupled with a home-built linear ion trap mass spectrometer (LIT-MS) under optimized conditions, polystyrene (PS) with masses up to two million daltons was successfully detected. This method using MALDI LIT-MS surpasses the previous upper detection limits observed with silver (Ag) and cesium (Cs) salts using a DCTB matrix. In the MALDI time-of-flight (TOF) mass spectrometry system, these salts were ineffective for detecting PS masses in the range from 660 kDa to 1.1 million Da, respectively (Rapid Commun. Mass Spectrom., 2015, 29, 1039-1046). In this study, we demonstrate for the first time that both Ag and Cu salts can successfully analyze UHMW PS samples up to 2 million Da using the trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]-malononitrile (DCTB) matrix. However, Ag salts predominantly generate multiply charged state ion signals with no control over charge states. In contrast, Cu salts demonstrate superior versatility in modulating charge states, with copper(I) salts achieving higher charge states of up to +5 and copper(II) salts generating lower charge states of up to +3. This targeted control simplifies analysis and enhances the method's flexibility, making Cu salts particularly valuable for analyzing both individual PS samples and mixtures. Additionally, Cu salts are compatible with both DCTB and all-trans-retinoic acid (RA) matrices, with DCTB delivering superior performance. Comparative analysis with Ag salts further validates Cu salts as optimal cationizing reagents for UHMW PS analysis, offering a powerful tool for mass distribution measurements in polymer research and advancing analytical methods in this field.

Template-assembly activation of primer exchange reaction for on-site and sensitive detection of copper ions in blood.

The sensitive and accurate detection of copper ions is crucial for public health, medical research, and environmental monitoring. In this study, we developed a sensor based on template-assembly activation of the primer exchange reaction (PER) for the on-site detection of copper ions in blood. Copper ions triggered the assembly of two template fragments into a hairpin structure via a click-chemistry reaction, activating the PER. Polymerase then repeatedly guided the polymerization of multiple primers along the assembled PER template, generating amplified products containing G-triplex sequences. These G-triplex structures specifically enhanced the fluorescence of thioflavin T and exhibited peroxidase-like activity, serving as dual-functional signal reporters for both fluorescence and colorimetric outputs. The sensor effectively amplified a single copper ion signal into multiple G-triplex signals, achieving high sensitivity with detection limits of 68.5nM in fluorescence mode and 70.4nM in colorimetric mode. The system also demonstrated strong selectivity, due to the high specificity of the click-chemistry reaction for copper ions. The dual-mode detection minimized false signals and improved accuracy through cross-verification. Additionally, both fluorescence and colorimetric signals were easily measurable without complex instrumentation, enabling flexible application. The method was successfully applied to blood samples, showcasing its robust performance. This sensor offers a promising alternative for copper ion detection with broad potential applications in public health, medical research, and environmental monitoring.

Atmospheric Pressure Mass Spectrometry Imaging Using Electrospray-Assisted Laser Desorption/Ionization with Gas Transportation through a Heated Tube and Minimal Sample Preparation

Mass spectrometry (MS) is a valuable tool that enables label-free analysis and the ability to measure multiple molecules. The atmospheric pressure MS imaging (MSI) method usually requires tedious sample preparation. A simple ionization method with minimal sample preparation is needed for high-throughput analysis. We have developed an ion source that does not require sample preparation such as thinning, curing, planarization, or addition of matrix by the electrospray-assisted laser desorption/ionization with gas transportation (ELDI-GT). The sample is transported with nitrogen gas through a heated tube to the electrospray. The ion signal of protonated caffeine was measured under different transport conditions. The ion signal intensity was found to increase 11-fold by changing the flow rate and tube temperature from 2.8 cm3/s and 473 K to 25 cm3/s and 673 K. ELDI-GT was able to visualize the localization of caffeine crystals at a pixel size of 50 µm using MSI because of the effective GT using the heated tube. The dependence of the ion signal intensity was discussed on the amount of heat applied to the sample in the heated tube. ELDI-GT allowed accurate localization of caffeine at a pixel size of 50 µm without the need to apply thinning and matrix to a sample.

Essential Oils from Citrus Peels Promote Calcium Overload-Induced Calcicoptosis in U251 Cells.

Citrus peel essential oils (CPEOs) have demonstrated substantial medicinal potential for glioblastoma treatment because of their extensive antitumor effects, low potential for drug resistance, and ability to cross the human blood-brain barrier. In this study, the chemical compositions of five CPEOs were analyzed via gas chromatography-mass spectrometry (GC-MS). CCK8 assays were used to evaluate the ability of five CPEOs to inhibit U251 human glioblastoma cells, and XLB and RA were selected for further investigation. Through wound healing assays and cell cycle and apoptosis analyses via flow cytometry, it was revealed that these CPEOs inhibited cell migration, arrested the cell cycle at G1/G0, and induced apoptosis with similar levels of inhibition. After CPEOs treatment, the intracellular Ca2+ content and reactive oxygen species levels in U251 cells increased significantly, whereas the mitochondrial membrane potential decreased. Additionally, the antioxidant enzyme system (SOD, POD, CAT, and GR) and the nonenzymatic defense system (GSH) were inhibited, leading to an increase in lipid peroxidation. qRT-PCR indicated the significant upregulation of intracellular calcium ion signaling pathways and the upregulation of mitochondrial apoptosis-related genes. Additionally, the activation of calcicoptosis-related indicators induced by the CPEOs could be reversed by inhibitor treatment, confirming that both of the selected CPEOs inhibit tumors by activating calcicoptosis-related pathways. These findings highlight the immense potential of CPEOs in healthcare and pharmaceutical applications by not only providing a scientific basis for the potential application of CPEOs in the treatment of glioblastoma but also offering new insights for the development of novel antitumor drugs.

FAST MS: Software for the Automated Analysis of Top-Down Mass Spectra of Polymeric Molecules Including RNA, DNA, and Proteins.

Top-down mass spectrometry (MS) enables comprehensive characterization of modified proteins and nucleic acids and, when native electrospray ionization (ESI) is used, binding site mapping of their complexes with native or therapeutic ligands. However, the high complexity of top-down MS spectra poses a serious challenge to both manual and automated data interpretation, even when the protein, RNA, or DNA sequence and the type of modification or the ligand are known. Here, we introduce FAST MS, a user-friendly software that identifies, assigns and relatively quantifies signals of molecular and fragment ions in MS and MS/MS spectra of biopolymers with known sequence and provides a toolbox for statistical analysis. FAST MS searches mass spectra for ion signals by comparing all signals in the spectrum with isotopic profiles calculated from known sequences, resulting in superior sensitivity and an increased number of assigned fragment ions compared to algorithms that rely on artificial monomer units while maintaining the false positive rate on a moderate level (<5%). FAST MS is an open-source, cross-platform software for the accurate identification, localization and relative quantification of modifications, even in complex mixtures of positional isomers of proteins, oligonucleotides, or any other user-defined linear polymer.

Integrated Transcriptomic, Proteomic, and Metabolomic Analyses Revealed Molecular Mechanism for Salt Resistance in Soybean (Glycine max L.) Seedlings.

Salt stress poses a significant challenge to plant growth and restricts agricultural development. To delve into the intricate mechanisms involved in soybean's response to salt stress and find targets to improve the salt resistance of soybean, this study integrated transcriptomic, proteomic, and metabolomic analyses to explore the regulatory networks involved in soybean salt tolerance. Transcriptomic analysis revealed significant changes in transcription factors, hormone-related groups, and calcium ion signaling. Notably, the biosynthetic pathways of cutin, suberine, and wax biosynthesis play an important role in this process. Proteomic results indicated salt-induced DNA methylation and the enrichment of phosphopyruvate hydrase post-salt stress, as well as its interaction with enzymes from various metabolic pathways. Metabolomic data unveiled the synthesis of various metabolites, including lipids and flavonoids, in soybean following salt stress. Furthermore, the integrated multiomics results highlighted the activation of multiple metabolic pathways in soybean in response to salt stress, with six pathways standing out prominently: stilbenoid, diarylheptanoid, and gingerol biosynthesis; carotenoid biosynthesis; carbon fixation in photosynthetic organisms; alanine, aspartate, and glutamate metabolism; thiamine metabolism; and pyruvate metabolism. These findings not only offer valuable insights into leveraging multiomics profiling techniques for uncovering salt tolerance mechanisms but also identify candidate genes for soybean improvement.

The Role of Phytochemicals in Managing Neuropathic Pain: How Much Progress Have We Made?

Neuropathic pain is a complex and debilitating condition resulting from nerve damage, characterized by sensations such as burning, tingling, and shooting pain. It is often associated with conditions such as multiple sclerosis (MS), Guillain-Barré syndrome (GBS), and diabetic polyneuropathy. Conventional pain therapies frequently provide limited relief and are accompanied by significant side effects, emphasizing the need to explore alternative treatment options. Phytochemicals, which are bioactive compounds derived from plants, have gained attention for their potential in neuropathic pain management due to their diverse pharmacological properties, including anti-inflammatory, antioxidant, and neuroprotective effects. This review evaluates the mechanisms by which specific phytochemicals, such as curcumin, resveratrol, and capsaicin, influence neuropathic pain pathways, particularly their role in modulating inflammatory processes, reducing oxidative stress, and interacting with ion channels and signaling pathways. While curcumin and resveratrol are primarily considered dietary supplements, their roles in managing neuropathic pain require further clinical investigation to establish their efficacy and safety. In contrast, capsaicin is an active ingredient derived from chili peppers that has been developed into approved topical treatments widely used for managing neuropathic and musculoskeletal pain. However, not all phytochemicals have demonstrated consistent efficacy in managing neuropathic pain, and their effects can vary depending on the compound and the specific condition. The pathophysiology of neuropathic pain, involving maladaptive changes in the somatosensory nervous system, peripheral and central sensitization, and glial cell activation, is also outlined. Overall, this review emphasizes the need for continued high-quality clinical studies to fully establish the therapeutic potential of phytochemicals in neuropathic pain management.

The Role of Dietary Magnesium in Cardiovascular Disease.

In the past 20 years, a large number of epidemiological studies, randomized controlled trials, and meta-analyses have found an inverse relationship between magnesium intake or serum magnesium and cardiovascular disease, indicating that low magnesium status is associated with hypertension, coronary artery calcification, stroke, ischemic heart disease, atrial fibrillation, heart failure, and cardiac mortality. Controlled metabolic unit human depletion-repletion experiments found that a mild or moderate magnesium deficiency can cause physiological and metabolic changes that respond to magnesium supplementation, which indicates that these types of deficiencies or chronic latent magnesium deficiency are contributing factors to the occurrence and severity of cardiovascular disease. Mechanisms through which a mild or moderate magnesium deficiency can contribute to this risk include inflammatory stress, oxidative stress, dyslipidemia and deranged lipid metabolism, endothelial dysfunction, and dysregulation of cellular ion channels, transporters, and signaling. Based on USA official DRIs or on suggested modified DRIs based on body weight, a large number of individuals routinely consume less magnesium than the EAR. This especially occurs in populations that do not consume recommended amounts of whole grains, pulses, and green vegetables. Thus, inadequate magnesium status contributing to cardiovascular disease is widespread, making magnesium a nutrient of public health concern.

Charge-exchange measurements of high-energy fast ions in LHD using negative-ion neutral beam injection

A new sightline geometry for the fast-ion D-alpha (FIDA) diagnostic on the Large Helical Device (LHD) has been confirmed to measure signals for high-energy fast ions produced by negative-ion neutral beam injection. The newly installed sightline uses a 180 keV tangential negative-ion neutral beamline as the active source. Due to the small angle between the beamline and FIDA sightline, the relative velocity between fast ions and injected neutrals is small. This allows for high-energy fast ions just below the beam injection energy to produce measurable Doppler-shifted FIDA emission. Experiments were conducted at LHD in order to compare the new sightline, which views a high-energy negative-ion tangential beamline, and the old sightline, which views a low-energy perpendicular positive-ion neutral beamline. The measured FIDA signal is validated against predictions from the synthetic fast-ion diagnostic code FIDASIM with a distribution function modelled by the 5D transport code GNET. The results of the experiment confirm that reducing the viewing angle with a tangential active beam allows FIDA diagnostic to view high-energy fast ions with a sufficient signal-to-noise ratio.

Development of a hydroponic device using potassium Ion-Selective electrode and neural network technology

The rapid development of modern agricultural biotechnology and information technology has become a key driver of modern agricultural growth. The demand for ion detection is prevalent in all aspects of agriculture. This study details the research on an ion sensor agricultural system using potassium (K) ion-selective electrodes (ISEs). The main emphasis is on the application of artificial neural networks (ANNs) for driving ISE development of accuracy. ISEs based on solid contact with metal oxides, specifically manganese dioxide, are studied. Moreover, the design details of an ion signal acquisition device using the NI-9205 acquisition card and LabVIEW are presented. Finally, based on experimental results of nutrient solution samples, ANNs show better performance than the multiple linear regression method. The mean relative error of K-ISE detection was maintained within 4%. This study thoroughly discusses ISE technology to promote its adoption in agriculture.

Two dimensional computational model of calcium and IP3 interacting system dynamics in an obese hepatocyte cell

Abstract Calcium ion (Ca2+) signaling is crucial in regulating numerous cellular processes vital for preserving structural integrity and functional equilibrium across diverse cell types. Both the calcium stores and mitochondria play significant roles in this signaling pathway. The calcium source may be in the form of a blip or a puff depending on the various conditions of the cellular systems. The one dimensional model of calcium dynamics with IP3 gives crucial insight of feedback mechanisms influencing calcium homeostasis. In order to obtain deeper insights of local impacts of various mechanisms and feedbacks in hepatocyte cell, it is necessary to develop the models in higher dimensions. In order to get more deeper insights, two dimensional model is proposed assuming the phenomena to be uniform along z dimension. This research presents a two-dimensional computational model to analyse the interactive system dynamics of inositol 1,4,5-trisphosphate (IP3) and Ca2+, aiming to assess how these signaling patterns influence hepatocyte functionality which allows to incorporate puff type of calcium source under both obese and normal physiological states. It further examines the implications of calcium signaling on NADH synthesis, ATP production, and degradation rates. Numerical simulations are executed utilising the Crank-Nicolson method for temporal analysis and the Linear Finite Element Method for spatial analysis. Additionally, the study conducts a comparative analysis of calcium signaling between obese and normal hepatocyte. The findings offer enhanced insights into the interactive system dynamics of IP3 and Ca2+ in hepatocytes, elucidating the effects of various parameter alterations on cellular behaviour in both states.