pH Monitoring Research Articles

Intelligent Magnetic Microrobots with Fluorescent Internal Memory for Monitoring Intragastric Acidity

AbstractThis study investigates the dynamic fluctuations of pH caused by gastric acid secretion, a process of both biological and clinical significance, with microrobots. Abnormal patterns of acidity often indicate gastrointestinal diseases, underlying the importance of precise intragastric pH monitoring. Traditional methods using fluorescent probes face challenges due to their faint solid‐state fluorescence, limited target specificity, and accuracy. To overcome these obstacles, pH‐responsive fluorescent organic microparticles decorated with magnetite (Fe3O4) nanoparticles are engineered. These microrobots exhibit a unique fluorescence switching capability at a critical pH, enabling the monitoring of gastric acidity. The magnetic part of these microrobots ensures magnetic maneuverability to enable targeted navigation. The microrobots’ fluorescence switching mechanism is elucidated through comprehensive spectroscopy, microscopy, and X‐ray diffraction analyses, revealing molecular‐level structural transformations upon interaction with gastric acid and antacids. These transformations, specifically protonation and deprotonation of the microrobots’ fluorescent components, prompt a distinct fluorescence response correlating with pH shifts. In vitro and ex vivo experiments, simulating stomach conditions, confirm the microrobots’ efficacy in pH‐responsive imaging. The results showcase the promising diagnostic potential of microrobots for gastrointestinal tract diseases, marking a significant advancement in imaging‐based medical diagnostics at targeted locations.

Hydrodynamics-engineered polyaniline nanofibers on graphene nanosheets for high-performance pH sensors

Real-time sweat monitoring in the human body using wearable sensors is promising for noninvasive and continuous healthcare applications. For reliable and accurate sweat analysis, further improvement in the response time and long-term stability of sensors is required. This paper reports an electrochemical pH sensor based on polyaniline/graphene (PANi-Gr) with rapid electron and ion transfer. The implementation of the Taylor–Couette flow approach allowed the efficient exfoliation of graphite into Gr nanosheets and the rapid polymerization of aniline monomers on the Gr surface, resulting in nanofiber PANi-deposited Gr nanocomposites. PANi-Gr had a large surface area and porous structure, which are favorable for rapid and stable electrochemical reactions. The screen-printed PANi-Gr-based pH sensor exhibited a Nernstian sensitivity of 61.91 mV/pH, rapid response time of <1 s, and long-term stability upon monitoring with minimal potential drift (0.04 mV h−1) under strong acidic and basic conditions. Furthermore, the on-body performance of the wearable pH sensor integrated with a wireless electronic device was analyzed via the noninvasive real-time monitoring of human sweat pH during stationary cycling. The developed sensor can be used in wearable real-time sweat monitoring devices for medical and healthcare applications.

Non-Acid GERC: Pathogenesis, Diagnosis and Management

Total Recent investigations have highlighted the pivotal influence of non-acid reflux in the etiology of chronic cough associated with gastroesophageal reflux disease (GERC). Differentiation between acid and non- acid GERC is effectively achieved through esophageal pH monitoring, with non-acid reflux drawing attention for its linkage to non-standard symptoms and the intricacies involved in its management. The combination of multi-channel intraluminal impedance with pH monitoring (MII-PH) and its related metrics, including acid exposure time (AET), symptom association probability (SAP), and symptom index (SI), as well as the quantity, pH, nature of reflux, its spread, and acid clearance time, alongside innovative measures such as mean nocturnal baseline impedance (MNBI) and post- reflux induced peristaltic wave index (PSWPI), is pivotal in precisely delineating reflux patterns and identifying the temporal connection between non-acid reflux occurrences and episodes of coughing. The prevailing reliance on proton pump inhibitors (PPIs) for treatment has encountered constraints in effectively managing non-acid GERC, underscoring the necessity for personalized treatment modalities that confront the unique pathophysiology of non-acid GERC to ameliorate patient outcomes. As research continues to deepen our understanding and enhance treatment methods for this multifaceted condition, the pursuit of effective treatment strategies becomes crucial. Our review aims to delineate the spectrum of therapeutic options, advancements in diagnostics, and an improved grasp of the pathogenesis of non-acid GERD. The focus of this review is to further the advancement of patient care management and to inspire continued research in this intriguing domain of gastroenterology.

Intraoperative monitoring of cerebrospinal fluid gas tension and pH before and after surgical revascularization for moyamoya disease.

This study aimed to directly measure cerebrospinal fluid (CSF) gas tensions and pH before and after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis for moyamoya disease. This study included 25 patients with moyamoya disease who underwent STA-MCA anastomosis combined with indirect bypass onto their 34 hemispheres. About 1 mL of CSF was collected before and after bypass procedures to measure CSF partial pressure of oxygen (PCSFO2), CSF partial pressure of carbon dioxide (PCSFCO2), and CSF pH with a blood gas analyzer. As the controls, the CSF was collected from 6 patients during surgery for an unruptured cerebral aneurysm. PCSFO2 and PCSFCO2 were expressed as the ratio to partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2), respectively. PCSFO2/PaO2 was 0.79 ± 0.14 in moyamoya disease, being lower than 1.10 ± 0.09 in the controls (P < 0.0001). PCSFCO2/PaCO2 was 0.90 ± 0.10 in moyamoya disease, being higher than 0.84 ± 0.07 in the controls (P = 0.0261). PCSFO2/PaO2 was significantly lower in pediatric patients than in adult patients and in the hemispheres with reduced cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide than in those with normal CBF but reduced CVR. STA-MCA anastomosis significantly increased PCSFO2/PaO2 from 0.79 ± 0.14 to 0.86 ± 0.14 (P < 0.01) and reduced PCSFCO2/PaCO2 from 0.90 ± 0.10 to 0.69 ± 0.16 (P < 0.0001). There was no difference in CSF pH between moyamoya disease and the controls. PCSFO2/PaO2 was significantly lower in moyamoya disease than in the controls. Its magnitude was more pronounced in pediatric patients than in adult patients and depends on the severity of cerebral ischemia. STA-MCA anastomosis carries dramatic effects on CSF gas tensions in moyamoya patients. CSF may be a valuable biomarker to monitor the pathophysiology of cerebral ischemia/hypoxia in moyamoya disease.

Single-Cell Sensitive Colorimetric pH Detection Based on Microscope Ratiometric Grayscale.

Rapid and accurate identification of the intracellular pH is critical in the field of biomedicine. In this work, we effectively identified and quantified the intracellular pH and its distribution at the single-cell level using an image sensor based on an ordinary bright-field optical microscope that divided the cell staining images into their red (R) and blue (B) channels. The grayscale of the R and B channels was subjected to a ratiometric operation to generate ratiometric grayscale cell images of the microscope. A standard curve of pH against ratiometric grayscale curve was then obtained by incubating HeLa cells at pH 6.00-7.60 in a high concentration K+ ion buffer solution containing nigericin for obtaining certain intracellular pH values. A good correlation was evidenced between pH and the ratiometric grayscale of the R and B channels in the pH range of 6.00-7.60. Subsequently, the intracellular pH value of the A549 cells under the experimental conditions was measured to be 7.22 ± 0.01 by the method. Furthermore, the changes in the intracellular pH of HeLa cells stimulated with hydrogen peroxide were sensitively monitored, which demonstrated the applicability of the method. Due to its ease of use, the developed colorimetric microscopy pH detection and monitoring method provide prospects for pH-related single-cell studies.

Formulation of Novel Microbial Consortia for Rapid Composting of Biodegradable Municipal Solid Waste: An Approach in the Circular Economy

Urbanization and rapid industrialization have led to the escalation of municipal solid waste generation and accumulation. Composting is widely recognized as a sustainable solution for solid waste management. However, its long-term investment is considered a disadvantage. The present research study discusses the rapid biotransformation of solid waste into valorized compost. Bacteria were isolated from soil, solid waste, and leachate samples from open dump sites. From the 18 different bacterial consortia created using potential isolates, the five most promising consortia were selected based on concurrent different enzyme production. These selected consortia were incorporated into typical compost bins with Municipal Solid Waste (MSW). Daily monitoring of enzymatic activity, pH, conductivity, bulk density, moisture, and temperature, along with other composting parameters, was conducted. The study’s results demonstrated that consortium No. 5, comprising Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, exhibited significant (p&lt;0.05) enzyme activity of cellulase, amylase, lipase and proteinase enzymes during composting compared to the control and other treatment setups. Consortium No. 5 also facilitated rapid and successful composting, as evidenced by significant alterations of composting parameters by exhibiting a shorter average composting time, reducing it from 110±10 days to 20±3 days, showcasing the potential applicability of formulated bacterial consortium as a sustainable and greener approach to the global solid waste problem. The novelty of this study lies in the isolation of local bacterial strains from open dump sites soil, MSW, and MSW leachate samples, which were then utilized in the composting organic fraction of MSW, enhancing the potential for effective waste management.

Journey into the Esophageal Complications: Decoding Systemic Sclerosis with Cutting-Edge Endoscopy, Manometry, and Ambulatory pH-Study.

Systemic Sclerosis (SSc) is a rare connective tissue disorder characterized by autoimmunity, fibrosis, and vasculopathy that affects the skin and internal organs, including the gastrointestinal tract, particularly the esophagus. This article highlights the characteristics and clinical symptoms of esophageal involvement in patients with SSc. This study was conducted between November 2022 to August 2023, including 26 already diagnosed cases of SSc in the Department of Rheumatology and Rehabilitation and Kurdistan Center for Gastroenterology and Hepatology-Sulaymaniyah, Iraq. Esophageal involvement was investigated using esophageal manometry, esophagogastroduodenoscopy (EGD), and 24-hour impedance-pH monitoring. Females were significantly predominant (P = 0.019) regarding the symptoms; 76.9% of the patients had heart burn, 76.9% dysphagia, 73.1% water brush, and 69.2% regurgitation. In total, 69.2% of the patients showed erosive gastrointestinal reflux disease (GERD) on EGD, 76.9% had decreased lower esophageal sphincter pressure (DLESP) and decreased distal esophageal peristaltic contractions (DDEPC) on esophageal manometry, and 84.6% had reflux on pH monitoring. Raynaud's phenomenon is the most common and typically the earliest clinical manifestation of SSc. The presence of erosive GERD was found to significantly increase the risk of developing dysphagia (B = 4.725, P = 0.014, OR = 3.482) and regurgitation (B = 3.521, P = 0.006, OR = 4.030). It is crucial to take gender-specific considerations into account when diagnosing and managing esophageal complications in patients with systemic sclerosis (SSc). Additionally, employing various diagnostic assessments to detect esophageal involvement during SSc is essential. Erosive GERD has been identified as a risk factor that contributes to the development of dysphagia and regurgitation in individuals with SSc.

Entirely Biodegradable Wireless pH Sensor with Split‐Ring Resonators for Soil pH Monitoring

AbstractThis paper describes a wireless and battery‐free soil pH sensor made entirely of degradable materials. Soil pH monitoring is significant for precision agriculture and environmental conservation because soil health can be estimated by measuring soil pH. Soil pH can be measured by collecting soil samples and analyzing them in a laboratory environment or by inserting an electrode‐type sensor into the soil and measuring soil pH on site. However, neither method is suitable for wide‐area soil pH sensing for precision agriculture or environmental conservation. Herein, a fully biodegradable wireless pH sensor is presented that can be dispersed to outdoor environment to detect soil acidity. The sensor is operated wirelessly through split‐ring resonators (SRRs) that consist of patterned octacalcium phosphate (OCP)‐coated magnesium (Mg) on a poly‐lactic acid (PLA) sheet. At acidic soil pH, the degradation of each SRR results in a change in the electromagnetic response of the sensor. The operation of the sensor in six different types of acidic soils is demonstrated to distinguish the acidic soil wirelessly. It is expected that the biodegradable sensor can be applied to low‐cost, easy‐to‐use, and environmentally friendly monitoring of soil pH.

A Versatile Electrochemical Cell for Operando XAS

AbstractIn situ and operando X‐ray absorption spectroscopy (XAS) provides fundamental insight into the working principles of electrocatalysts and is an important tool for future catalyst development. However, the design of an operando XAS electrocatalytic cell is not facile, and researchers designing cells, whether new cells or modifications to previous cells, often spend many hours on cell design before obtaining high‐quality XAS data. Here, we describe the design, with engineering drawings, and operation of a versatile XAS cell with options for gas flow, electrolyte flow, pH monitoring, temperature monitoring, and the ability to handle many catalyst forms (any catalyst that can be deposited onto a conductive X‐ray transparent substrate). We benchmarked XAS spectra collected using the new experimental cell to a previous cell design showing its ability to produce quality XAS data. We demonstrate the viability of this cell by providing insight into electrocatalysts by studying cation effects and show the tetrabutylammonium cation prevents bulk oxidation of copper. We hope the availability of this cell allows researchers to convert time typically spent on cell design to time spent on breakthroughs in electrocatalysis.

The development of an IoT-based automated temperature and pH monitoring system to enhance the management of gourami fish ponds

This research aims to develop an Internet of Things (IoT)-based automated system for monitoring temperature and pH in the context of gourami fish farming. Gourami fish ponds are often situated in various environments with significant variations in environmental conditions. The system is designed to enable pond owners to remotely monitor real-time water temperature and pH, which are key factors in maintaining optimal water quality and fish health. The temperature sensor used is the DS18B20, while the pH sensor used is the E210C. The ESP32 platform is employed due to its integrated Wi-Fi capabilities. Monitoring displays are accessible on an LCD, personal computer (PC), and smartphone. This research involves the calibration and validation of temperature and pH sensors to ensure accurate measurements. The average standard deviation value for the temperature sensor is 0.092, and for the pH sensor, it is 0.031. The average accuracy of the temperature sensor is 98.60%, while the pH sensor has an average accuracy of 98.41%. The results demonstrate that IoT-based temperature and pH monitoring allow for in-depth data analysis of environmental conditions and long-term trend analysis in pond management.

Polyvinyl alcohol-enhanced intelligent films for the accurate monitoring of pH via anthocyanin-induced color changes

Polyvinyl alcohol-enhanced intelligent films for the accurate monitoring of pH via anthocyanin-induced color changes

An Anthocyanin-Based Eco-Friendly Triboelectric Nanogenerator for pH Monitoring and Energy Harvesting.

In recent years, renewable and sustainable triboelectric nanogenerators have attracted attention due to their high energy conversion rate, and enhancing their functionality further contributes to their applicability across various fields. A pH-sensitive triboelectric nanogenerator (pH-TENG) has been prepared by electrostatic spinning technology, with anthocyanin as the pH indicator and environmentally friendly polyvinyl alcohol (PVA) as the substrate. Among many friction-negative materials, the pH-TENG exhibits the best combination with fluorinated ethylene propylene (FEP) and yields an open-circuit voltage of 62 V, a short-circuit current of 370 nA, and a transferred charge of 21.8 nC. At a frequency of 3 Hz, it can charge a 4.7 μF capacitor to 2 V within 45 s, effectively powering a thermometer. Furthermore, the presence of anthocyanin does not affect the pH-TENG's power generation performance and enables the monitoring of a wide range of environmental pH changes, with an ΔE change of 28.8 ± 7.6. Therefore, pH-TENG prepared with environmentally friendly materials can bring new available materials to the biological and medical fields.

Chromium immobilization in basic magnesium sulfate cement: Experimental and density functional theory studies

This study investigated the effects of different concentrations of Cr(III) on the properties of basic magnesium sulfate cement (BMSC). In addition, the hydration process of BMSC with different concentrations of Cr(III) was studied using isothermal calorimetry and in-situ pH monitoring. A combined experimental approach and density functional theory simulation was further employed to investigate the solidification mechanism of Cr(III) in BMSC. The results indicated that Cr(III) affected the hydration heat, pH value, compressive strength and setting time of BMSC, and the influence became more obvious with the increase of Cr(III) concentration. In addition, the solidification efficiency of Cr(III) in BMSC was up to 99.9%; the efficient solidification of Cr(III) in BMSC primarily operated through ion exchange interactions, as revealed by density functional theory simulation and phase analysis results. Furthermore, the BMSC matrix after being immersed in simulated acid rain solutions for 28 days had a compressive strength of over 45 MPa, showing remarkable resistance to acids.

Bioresorbable, wireless, passive sensors for continuous pH measurements and early detection of gastric leakage.

Continuous monitoring of biomarkers at locations adjacent to targeted internal organs can provide actionable information about postoperative status beyond conventional diagnostic methods. As an example, changes in pH in the intra-abdominal space after gastric surgeries can serve as direct indicators of potentially life-threatening leakage events, in contrast to symptomatic reactions that may delay treatment. Here, we report a bioresorbable, wireless, passive sensor that addresses this clinical need, designed to locally monitor pH for early detection of gastric leakage. A pH-responsive hydrogel serves as a transducer that couples to a mechanically optimized inductor-capacitor circuit for wireless readout. This platform enables real-time monitoring of pH with fast response time (within 1 hour) over a clinically relevant period (up to 7 days) and timely detection of simulated gastric leaks in animal models. These concepts have broad potential applications for temporary sensing of relevant biomarkers during critical risk periods following diverse types of surgeries.

Exploring the Impact of Cationic Surfactant Ctab on Bleu Brilliant G 250 De Cosmassie: Implications for Health Management and Environmental Sustainability

Background: Surfactants are ubiquitous in both natural and industrial processes due to their unique ability to reduce surface tension and facilitate interactions between hydrophilic and hydrophobic substances. Cationic surfactants like cetyltrimethylammonium bromide (CTAB) are of particular interest because of their widespread applications in areas such as healthcare and environmental management. The interaction between surfactants and dyes, such as Bleu Brilliant G 250 de Cosmassie, is critical in industrial processes, especially in the textile industry where wastewater treatment poses significant environmental challenges. Objective: The aim of this study was to explore the thermodynamic behavior of CTAB when combined with Bleu Brilliant G 250 de Cosmassie in aqueous solutions at room temperature. It sought to determine the critical micelle concentration (CMC) and the degree of counter-ion dissociation (α), and to calculate the changes in Gibbs free energy (ΔGm), enthalpy (ΔHm), and entropy (ΔSm) of the system. Methods: The study employed conductometric and spectrophotometric techniques to analyze the CTAB-dye interactions. Solutions were prepared with varying concentrations of CTAB and Bleu Brilliant G 250 de Cosmassie in deionized water, ensuring solvent purity through stringent conductivity and pH monitoring. Electrical conductance was measured at different temperatures to determine the CMC, while absorbance spectra were recorded to observe changes in the interaction between the surfactant and dye. The degree of counter-ion dissociation was calculated by the slope ratio method, and thermodynamic parameters were computed using established equations. Results: The conductometric studies revealed an increase in CMC with temperature, indicating a stabilization of surfactant monomers at higher temperatures. For CTAB and Bleu Brilliant system 1, the CMC was found to be 0.8 with α valued at 0.83. For system 2, the CMC values were 1.55 and 1.6 with α values of 1.01 and 0.91, respectively. Thermodynamically, the system displayed a Gibbs free energy of micellization of -33.09 KJ/mol, an enthalpy change of -6.53, and an entropy change of 0.1325 JK^-1 mol^-1. Conclusion: The study concluded that the interaction between CTAB and Bleu Brilliant G 250 de Cosmassie is influenced significantly by temperature, which affects the micellization behavior and thermodynamic properties. The findings contribute to a better understanding of the fundamental thermodynamic parameters influencing surfactant-dye interactions, providing insights that may improve industrial processes and environmental sustainability.

Bridging biological and food monitoring: A colorimetric and fluorescent dual-mode sensor based on N-doped carbon dots for detection of pH and histamine

Rapid and sensitive monitoring of pH and histamine is crucial for bridging biological and food systems and identifying corresponding abnormal situations. Herein, N-doped carbon dots (CDs) are fabricated by a hydrothermal method employing dipicolinic acid and o-phenylenediamine as precursors. The CDs exhibit colorimetric and fluorescent dual-mode responses to track pH and histamine variations in living cells and food freshness, respectively. The aggregation-induced emission enhancement and intramolecular charge transfer result in a decrease in absorbance and an increase in fluorescence, which become readily apparent as the pH changes from acidic to neutral. This property enables precise differentiation between normal and cancerous cells. Furthermore, given the intrinsic basicity of histamine, pH-responsive CDs are advantageous for additional colorimetric and fluorescent monitoring of histamine in food freshness, achieving linearities of 25–1000 µM and 30–1000 µM, respectively, which are broader than those of alternative nanoprobes. Interestingly, the smartphone-integrated sensing platform can portably and visually evaluate pH and histamine changes due to sensitive color changes. Therefore, the sensor not only establishes a dynamic connection between pH and histamine for the purposes of biological and food monitoring, but also presents a novel approach for developing a multifunctional biosensor that can accomplish environmental monitoring and biosensing simultaneously.

In-situ fabrication of tungsten oxide film pH micro-sensor and its application on the pH monitoring of Fe-Cu galvanic corrosion

Localized and interface pH values are important parameters for studying the corrosion progress and complex interface reactions. Although commercial glass pH sensors have been widely used to measure solution pH value due to their advantages of long stability and high sensitivity, they were unable to determine the interface and microregion pH value for their difficulty in miniaturization. In this work, an all-solid-state pH micro-sensor with strong adhesion strength was in-situ fabricated on diameter 15 μm tungsten ultramicroelectrode (UME) using constant current anodizing. The pH micro-sensor showed good linear response (R2 = 0.999), excellent sensitivity (with a slope of −53.8 mV/pH), quick response (<0.1 s), long lifetime (>44 days) and great anti-interference ability to most of the ions in marine (selectivity coefficients pKij > 7), such as SO42−, Cl−, NO3−, K+, Mg2+ and Fe2+. Then, the pH micro-sensor, combined with the potentiometric mode of SECM, was further employed to explore the localized pH value distribution during the galvanic corrosion of Fe-Cu couple in 0.1 M NaCl solution. To further verify the anti-interference ability of pH micro-sensor, potentiometric SECM experiment was also conducted in artificial seawater. Results showed that both acidic sites and alkalizing sites appeared on the Fe surface, while homogeneous alkalization took place overall Cu surface. This was consistent with the SVET results that anodic and cathodic areas existed simultaneously on Fe surface. Thus, it could be concluded that local corrosion occurred on Fe surface and only part of the Fe surface acted as the anodic even under galvanic effect. However, Cu acted as cathode with the homogeneously distributing cathodic current on the whole surface during the galvanic corrosion.

Use of flexible transnasal esophagogastroscopy in patients with unclear globus sensation

Globus pharyngeus is acommon symptom with considerable suffering. Globus sensation can be caused by reflux. In many places, endoscopy of the esophagus is recommended for clarification, especially when there is aquestion about the presence of ahiatal hernia as the cause of reflux. Transnasal esophagogastroscopy (TNE) represents an alternative to conventional gastroesophagoscopy. It enables aquick low-complication examination of the upper aerodigestive tract in the sitting, non-sedated patient. The aim of this work was to assess the feasibility of outpatient TNE in patients with globus sensation. Furthermore, the results of dual-probe pH monitoring were compared with the results of TNE in order to assess the value of TNE in the clarification of globus sensation and reflux. In 30patients with globus symptoms, 24-hour dual-probe pH monitoring and TNE were performed. In pH monitoring, reflux number, fraction time, reflux surface area index, and DeMeester score were evaluated as indicators of laryngopharyngeal reflux (LPR) and gastroesophageal reflux (GERD). Abnormalities of the esophageal mucosa and the gastroesophageal junction were recorded in TNE. The results were compared. The TNE could be performed without any complications. Mean examination time was 5.34 ± 0.12 min. Reflux was measured in 80% of the patients (24/30) with pH monitoring. In almost half of these patients (46%), abnormalities were detected in TNE as indirect evidence of reflux. In addition to an axial hiatal hernia, these included mucosal changes such as erosive esophagitis and Barrett's metaplasia. Patients with ahiatal hernia also suffered significantly more often from LPR than patients without ahernia (9:1). TNE is aquick and safe examination method for diagnosing patients with an unclear globus sensation. Detection of ahiatal hernia can be seen as an indication of reflux disease. Lack of evidence of ahernia does not rule out reflux. Thus, TNE is auseful addition to pH monitoring in patients with globus sensation, because reflux-related changes in the mucosa can be recognized early and adequately treated.

SERS-based long-term mitochondrial pH monitoring during differentiation of human induced pluripotent stem cells to neural progenitor cells

As one of the important organelles in the process of cell differentiation, mitochondria regulate the whole process of differentiation by participating in energy supply and information transmission. Mitochondrial pH value is a key indicator of mitochondrial function. Therefore, real-time monitoring of mitochondrial pH value during cell differentiation is of great significance for understanding cell biochemical processes and exploring differentiation mechanisms. In this study, Surface-enhanced Raman scattering (SERS) technology was used to achieve the real-time monitoring of mitochondrial pH during induced pluripotent stem cells (iPSCs) differentiation into neural progenitor cells (NPCs). The results showed that the variation trend of mitochondrial pH in normal and abnormal differentiated batches was different. The mitochondrial pH value of normal differentiated cells continued to decline from iPSCs to embryoid bodies (EB) day 4, and continued to rise from EB day 4 to the NPCs stage, and the mitochondrial microenvironment of iPSCs to NPCs differentiation became acidic. In contrast, the mitochondrial pH value of abnormally differentiated cells declined continuously during differentiation. This study improves the information on acid-base balance during cell differentiation and may provide a basis for further understanding of the changes and regulatory mechanisms of mitochondrial metabolism during cell differentiation. This also helps to improve more accurate and useful differentiation protocols based on the microenvironment within the mitochondria, improving the efficiency of cell differentiation.

Correlation of the Endoscopic Gastroesophageal Flap Valve with Pathologic Reflux.

The Hill classification characterizes the geometry of gastroesophageal junction and Hill grades (HGs) III and IV have a high association with pathologic reflux. This study aimed to understand the use of the Hill classification and correlate the prevalence of pathologic reflux across different HGs. A retrospective review of 477 patients who underwent upper endoscopy and BRAVO pH monitoring between August 2018 and October 2021 was performed. These charts were reviewed for endoscopic findings for hiatal hernia and association of HGs with pathologic reflux, defined as an abnormal esophageal acid exposure time (AET) of ≥4.9%. Of 477 patients, 252 (52.8%) had an HG documented on the endoscopy report. Of the 252 patients, 61 had HG I (24.2%), 100 had HG II (39.7%), 61 had HG III (24.2%), and 30 had HG IV (11.9%). The proportion of patients with abnormal AET increases with increasing HGs (p < 0.001) as follows: I (39.3%), II (52.5%), III (67.2%), and IV (79.3%). The mean overall AET is as follows: HG I (5.5 ± 6%), HG II (7.0 ± 5.9%), HG III (10.2 ± 10.3%), and HG IV (9.5 ± 5.5%). The proportion of patients with hiatal hernia was 18% for HG I, 28% for HG II, 39.3% for HG III, and 80% for HG IV. Use of the Hill classification in clinical practice is low. There is an association of increasing HGs with increasing proportion of patients with abnormal AET. There is a high proportion of patients within HGs I and II with documented pathologic reflux and the presence of a hiatal hernia as observed on endoscopic examination. Our study suggests that endoscopic grading of the gastroesophageal junction may not adequately differentiate between normal vs abnormal reflux status, particularly for HGs I and II.