[A case of small intestinal endometriosis with bowel obstruction and perforation].

A 47-year-old woman was referred to our hospital with recurring lower abdominal pain persisting for more than 2 weeks. Imaging modalities showed small bowel obstruction caused by a mass lesion in the terminal ileum. Despite undergoing fasting, rehydration, and decompression through an ileus tube, her symptoms persisted. Furthermore, the condition deteriorated on day 4, with the onset of her menstrual period. An emergency surgery was conducted on the 7th day after hospitalization. Surgical observations indicated severe stenosis around the ileocecal valve and ileal perforation approximately 40cm from the oral stricture. As a result, ileocecal resection was performed. Pathological examination revealed endometrial tissue infiltration through the mucosal lamina propria to the ileal subserosa. Thus, the patient was identified with intestinal endometriosis of the ileocecum. Endometriosis of the small bowel is an uncommon condition that eventually causes intractable bowel obstruction. Although preoperative diagnosis is considered challenging, intestinal endometriosis should be included in the differential diagnosis in cases of bowel obstruction in women of childbearing age.

CA125 Kinetics as a Potential Biomarker for Peritoneal Metastasis Progression following Taxane-Plus-Ramucirumab Administration in Patients with Advanced Gastric Cancer.

Currently, no established marker exists for predicting peritoneal metastasis progression during chemotherapy, although they are major interruptive factors in sequential chemotherapy in patients with advanced gastric cancer (AGC). This multicenter retrospective study was conducted from June 2015 to July 2019, analyzing 73 patients with AGC who underwent taxane-plus-ramucirumab (TAX/RAM) therapy and had their serum carbohydrate antigen 125 (CA125) concentrations measured. Of 31 patients with elevated CA125 levels above a cutoff of 35 U/mL, 25 (80.6%) had peritoneal metastasis. The CA125 concentrations before TAX/RAM treatment were associated with ascites burden. The overall survival was significantly shorter in the CA125-elevated group. CA125 kinetics, measured at a median of 28 days after chemotherapy, were associated with the ascites response (complete or partial response: -1.86%/day; stable disease: 0.28%/day; progressive disease: 2.33%/day). Progression-free survival in the CA125-increased group, defined by an increase of 0.0067%/day using receiver operating characteristic curve analysis, was significantly poorer among patients with peritoneal metastases. In conclusion, this study highlights that CA125 kinetics can serve as an early predictor for the progression of peritoneal metastasis during TAX/RAM treatment.

The Efficacy and Safety of Nivolumab Plus mFOLFOX6 in Gastric Cancer with Severe Peritoneal Metastasis.

(1) Background: Nivolumab plus chemotherapy is established as a first-line treatment for advanced gastric cancer (AGC). While mFOLFOX6 is commonly used for AGC with severe peritoneal metastasis, the efficacy of nivolumab combined with it remains uncertain. We evaluated the outcomes of nivolumab plus mFOLFOX6 for AGC with severe peritoneal metastasis in clinical practice. (2) Methods: This multicenter retrospective study was conducted between December 2021 and June 2023. We investigated AGC patients with massive ascites or inadequate oral intake due to severe peritoneal metastasis and who received nivolumab plus mFOLFOX6. (3) Results: Among 106 patients treated with nivolumab plus chemotherapy, 21 (19.8%) had severe peritoneal metastasis, with 14 receiving nivolumab plus mFOLFOX6. The median progression-free survival was 7.4 months (95%CI 1.9-10.1), and the median overall survival was 10.7 months (95%CI 5.3-NA), with four patients (28.5%) surviving more than 12 months. Improved ascites and oral intake were observed in 6/14 patients (42.8%) and 10/11 patients (90.9%), respectively. The major grade 3 or more adverse events included leukopenia (28.5%) and neutropenia (21.4%), with no severe immune-related adverse events reported. (4) Conclusions: The safety and moderate efficacy of nivolumab plus mFOLFOX6 were suggested even in AGC patients with severe peritoneal metastasis.

Liver metastasis affects progression pattern during immune checkpoint inhibitors monotherapy in gastric cancer.

Introduction: The efficacy of immune checkpoint inhibitors (ICIs) is heterogeneous at each metastatic site, and tumor progression pattern is associated with survival; however, it remains unclear in gastric cancer (GC). Therefore, we aimed to clarify the progression pattern in response to ICIs in patients with GC, and we analyzed its mechanism focusing on the intratumoral immune cells. Methods: Patients who received ICIs were retrospectively classified into non-systemic and systemic progression groups based on their radiological assessments. Moreover, the best percentage change in target lesions from each organ was compared. Results: Among 148 patients, the non-systemic progression group showed a significant improvement in overall survival (OS) compared with the systemic progression group (median, 5.6 months vs. 3.3 months; HR, 0.53; 95%CI, 0.32-0.89; p = 0.012). Poor performance status (HR, 1.73, 95%CI, 1.00-2.87) and systemic progression (HR, 3.09, 95%CI, 1.95-4.82) were associated with OS. Of all metastatic sites, the liver showed the poorest percentage change, and liver metastasis (OR, 2.99, 95%CI, 1.04-8.58) was associated with systemic progression. Hence, intratumoral CD8+ T-cell density was lower in patients with liver metastasis than in those without liver metastasis after ICIs, although the density of CD4+ T-cells (Th1, Th17, and Treg) and CD163+ cells (TAM) were not significantly different. Conclusion: The new progression pattern was associated with OS in GC. Liver metastasis may be a predictive factor of systemic progression during ICIs by regulating intratumoral CD8+ T-cells.

Factors, Including Clinical Trial Eligibility, Associated with Induction of Third-Line Treatment for Advanced Gastric Cancer.

INTRODUCTION: Third-line chemotherapy has been suggested to improve survival in patients with gastric cancer. This study aimed to identify factors associated with the induction of third-line chemotherapy for advanced gastric cancer, focusing on patient eligibility for clinical trial. METHODS: We retrospectively analyzed 335 patients treated for unresectable or recurrent gastric cancer between April 2009 and May 2020. The patients were grouped into those that met the key eligibility criteria for clinical trial (136 patients, 40.6%) and those that did not (199 patients, 59.4%) before receiving first-line chemotherapy. RESULTS: The overall survival (OS) was 16.8 months (95% CI: 14.0-19.6) and 9.3 months (95% CI: 7.8-11.0) in the eligible and ineligible group, respectively. Multivariate analyses to identify the risk factors associated with the induction of third-line chemotherapy revealed ineligibility of clinical trial (OR 1.95; 95% CI: 1.15-3.31), number of metastatic sites (OR 1.99; 95% CI: 1.23-3.22), low albumin concentration (OR 2.24; 95% CI: 1.14-4.38), and a lack of complete or partial response to first-line treatment (OR 1.85; 95% CI: 1.05-3.26). Indeed, in responders to first-line treatment for ineligible patients, the median OS was 17.7 months (95% CI: 10.6-27.9), respectively. CONCLUSIONS: Treatment outcomes were different for those eligible for clinical trials and those who were not. However, this study suggested that patients who responded to first-line treatment have more favorable prognosis when treated with salvage chemotherapy, even if they were deemed ineligible for clinical trials.

Partially Oxidized Purely Organic Zwitterionic Neutral Radical Conductor: Multi-step Phase Transitions and Crossover Caused by Intra- and Intermolecular Electronic Interactions.

Formation of a partially charge-transfer or partially oxidized/reduced state has been one of the most important requirements for the development of highly conducting molecular materials, such as organic metals and superconductors. This requirement has been fulfilled by combining appropriate electron-donor and acceptor molecules to construct multi-component molecular complexes/salts, such as (TTF+0.59)(TCNQ-0.59) and (BEDT-TTF+0.5)2X-, where TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane, BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, and X = monovalent inorganic anion. Here, we propose a methodology to fulfill this requirement by a single neutral molecule; namely, we have connected two TTF+0.5-type partially oxidized π-skeletons through a boron anion to design a purely organic zwitterionic neutral radical {[(PDT-TTF-Cat)2]+B-}•. This molecule was successfully obtained as air-stable crystals containing solvent tetrahydrofuran (THF) molecules. Measurements of electrical resistivity, magnetic susceptibility, and X-ray diffraction reveal that the partially oxidized state is certainly formed, which enables realization of a 3/4-filled electron band. Furthermore, this system has intramolecular charge degrees of freedom, attributable to the two TTF+0.5 π-skeletons introduced into the molecule. The resulting interplay of intra- and intermolecular charge degrees of freedom (or simply, intra- and intermolecular electronic interactions) has led to multi-step phase transitions and crossover, providing unique strongly correlated electron properties, such as the formation of a three-dimensional charge-ordered dimer-Mott insulating state and its melting triggered by disorder-order transformation of the co-crystallized solvent THF molecules at low temperatures.

U-shaped plastic optical fiber sensor for scale deposition in hot spring water.

Fiber optic sensors for monitoring scale deposition in geothermal brine and hot spring water should be safe, easily fabricated, and readily disposable. These desired features already have been enhanced in plastic optical fibers (POFs) and U-shaped sensors for other applications. The present work reports a U-shaped POF sensor for CaCO3 scale deposition. The sensors were easily fabricated by thermally bending the bulk POF without removing the cladding. At the bend, the percentage of total internal reflection between the water and the POF surface is affected by the high refractive index of the CaCO3 deposit. The optical responses of the U-shaped sensor to CaCO3 formation were investigated in a mixture of calcium chloride dehydrate and sodium hydrogen carbonate using a white-light source and a spectroscopic detector. The sensor was responsive to CaCO3 formation on the sensor surface and was especially sensitive at small bending radii. The sensitivity was further enhanced by increasing the number of bends. Finally, the U-shaped POF sensor was applied to the monitoring of CaCO3 scale deposition in hot spring water sampled at Matsushiro, Japan.

Efficacy and Safety of FOLFOX in Advanced Gastric Cancer Initially Presenting With Disseminated Intravascular Coagulation.

BACKGROUND/AIM: Advanced gastric cancer (AGC) rarely presents with disseminated intravascular coagulation (DIC) at the time of diagnosis. Chemotherapy should be selected in consideration of hematological toxicities because these patients are at high risk of hemorrhagic complications. The leucovorin, fluorouracil, and oxaliplatin (FOLFOX) regimen is an effective and less toxic regimen for patients with AGC and poor performance status. PATIENTS AND METHODS: The present study assessed overall survival of all patients receiving first-line chemotherapy with and without DIC using Kaplan-Meier methods and examined the clinicopathological factors, DIC parameters, response, and survival of five patients with AGC and DIC who received FOLFOX in the first-line setting between February 2017 and February 2020. RESULTS: Among the patients, four patients (80%) recovered from DIC after a median of 12 days of FOLFOX therapy (range=12-25), and their platelet count gradually increased within 1 week after the start of chemotherapy. The median progression-free survival and overall survival were 46 (range=22-296) and 115 days (range=83-324), respectively. No patients experienced adverse events necessitating treatment discontinuation, including gastrointestinal bleeding and thrombocytopenia. Moreover, all patients received second-line treatment after progression, and one patient exhibited improvement of DIC symptoms following nab-paclitaxel and ramucirumab treatment. CONCLUSION: FOLFOX therapy is well tolerated and effective in patients with AGC initially presenting with DIC and subsequent second-line treatment might be crucial for better prognosis.

Reversible Insulator-Metal Transition by Chemical Doping and Dedoping of a Mott Insulator.

The chemical carrier doping of molecular Mott insulators has been poorly investigated to date due to its difficulty. In this study, iodine doping of a molecular Mott insulator, lithium phthalocyanine crystallized in the x-form (x-LiPc), was performed to obtain metallic x-LiPcI. Crystal structure analysis revealed that iodine atoms penetrated channels of x-LiPc and formed one-dimensional chains. The Raman spectroscopy of x-LiPcI indicated the existence of linear I5 - , demonstrating a transition from a half-filled band of the Mott insulating state to a 2/5-filled band of the metallic state. Electrical resistivity measurements confirmed the metallic nature of x-LiPcI, whereas a thermally activated behavior was observed for pristine x-LiPc. Furthermore, the x-LiPc Mott insulator was reproduced by dedoping iodine from x-LiPcI, suggesting that the electronic state can be reversibly tuned between the Mott insulating and metallic states by chemical doping and dedoping.

Double-σ-Bonded Close-Shell Dimers and Peroxy-Linked Open-Shell Dimer Derived from a C3 Symmetric Trioxophenalenyl Neutral Diradical.

A novel neutral diradical of π-extended phenalenyl derivative having three oxo-groups, tri-tert-butyl-1,4,7-trioxophenalenyl, and two types of the corresponding σ-dimers were investigated. Quantum chemical calculations showed that the neutral diradical is in triplet ground state having doubly degenerate singly occupied molecular orbitals. The neutral diradical undergoes a σ-dimerization, generating two types of σ-dimers immediately after the preparation. One of the σ-dimers, which was selectively generated in the crystalline state, was a close-shell dimer linked through double-σ-bonds on the phenalenyl skeleton with a long C-C bond length of 1.66 Å. The other σ-dimer, which existed only in the solution state, was a peroxy-linked open-shell dimer in which one σ-bond was formed between two oxygen atoms. Furthermore, the temperature-dependent 1 H NMR and ESR spectra revealed that these σ-dimers are in equilibrium in the solution state by the reversible σ-bond formation/cleavage via the neutral diradical as a key intermediate.

Proton-electron-coupled functionalities of conductivity, magnetism, and optical properties in molecular crystals.

Proton-electron-coupled reactions, specifically proton-coupled electron transfer (PCET), in biological and chemical processes have been extensively investigated for use in a wide variety of applications, including energy conversion and storage. However, the exploration of the functionalities of the conductivity, magnetism, and dielectrics by proton-electron coupling in molecular materials is challenging. Dynamic and static proton-electron-coupled functionalities are to be expected. This feature article highlights the recent progress in the development of functionalities of dynamic proton-electron coupling in molecular materials. Herein, single-unit conductivity by self-doping, quantum spin liquid state coupled with quantum fluctuation of protons, switching of conductivity and magnetism triggered by the disorder-order transition of deuterons, and their external responses under pressure and in the presence of an electric field are introduced. In addition, as for the functionalities of proton-d/π-electron coupling in metal dithiolene complexes, magnetic switching with multiple PCET and vapochromism induced by electron transfer through hydrogen-bond (H-bond) formation is introduced experimentally and theoretically. We also outlined the basic and applied issues and potential challenges for development of proton-electron-coupled molecular materials, functionalities, and devices.

Design and Synthesis of a C3 Symmetrical Phenalenyl Derivative with Three Oxo Groups by Regioselective Deoxygenation/Oxygenation.

Tri-tert-butylated 4,7-dihydroxyphenalenone was designed and synthesized from a corresponding 4,9-dimethoxyphenalenone derivative by regioselective deoxygenation/oxygenation. The 4,7-dihydroxyphenalenone derivative showed a chromic behavior accompanied by protonation and deprotonation, giving monocation and dianion species, respectively, and their C3 symmetric electronic structures were elucidated by experimental and theoretical methods.

Synthesis of mesoporous silica from geothermal water.

Mesoporous silica was successfully synthesized for the first time using geothermal water from the Onuma Geothermal Power Plant, Akita Prefecture, Japan. Cetyltrimethylammonium bromide (CTAB) was used as an organic template for the synthesis. CTAB with a concentration of 2.4 × 10-4 mol/L was reacted for 30 min with geothermal water at a temperature of 90 °C, which had a total silicic acid concentration of 475 mg/L (SiO2), at pH 7.0, pH 8.2 (raw water) and pH 9.0. By calcination of the resulting precipitate at 550 °C, mesoporous silica with a pore size of about 2.8 nm and a specific surface area of > 800 m2/g was formed. The total silicic acid concentration in the solution after formation of the mesoporous precipitates was reduced to < 280 mg/L, indicating efficient recovery of supersaturated silicic acid from geothermal water. The monosilicic acid in geothermal water plays an important role in the formation of mesoporous silica. Production of mesoporous silica by our method will contribute not only to prevention of silica scale formation in the piping systems of geothermal power plants but also to its use as an industrial resource.

Construction and commissioning of mid-infrared self-amplified spontaneous emission free-electron laser at compact energy recovery linac.

The mid-infrared range is an important spectrum range where materials exhibit a characteristic response corresponding to their molecular structure. A free-electron laser (FEL) is a promising candidate for a high-power light source with wavelength tunability to investigate the nonlinear response of materials. Although the self-amplification spontaneous emission (SASE) scheme is not usually adopted in the mid-infrared wavelength range, it may have advantages such as layout simplicity, the possibility of producing a single pulse, and scalability to a short-wavelength facility. To demonstrate the operation of a mid-infrared SASE FEL system in an energy recovery linac (ERL) layout, we constructed an SASE FEL setup in cERL, a test facility of the superconducting linac with the ERL configuration. Despite the adverse circumstance of space charge effects due to the given boundary condition of the facility, we successfully established the beam condition at the undulators and observed FEL emission at a wavelength of 20 µm. The results show that the layout of cERL has the potential for serving as a mid-infrared light source.

Synthesis and Physical Properties of Trioxotriangulene Having Methoxy and Hydroxy Groups at α-Positions: Electronic and Steric Effects of Substituent Groups and Intramolecular Hydrogen Bonds.

New 4,8,12-trioxotriangulene (TOT) neutral radical derivatives having three methoxy and hydroxy groups at the α-positions were synthesized, and the substituent effects on the electronic spin and redox properties were elucidated in the theoretical and experimental methods. Due to the small SOMO coefficients at the α-positions of TOT, the methoxy groups in the TOT neutral radical had negligible effects on the electronic spin structure and redox ability. On the other hand, methoxy groups greatly increased the LUMO energy having large coefficients at α-positions and, thus, caused a remarkable negative-potential shift of the redox wave of anion species involving the dianion and trianion species. Converting the methoxy groups to hydroxy groups caused a dramatic change in the electronic structure of TOT, where the intramolecular hydrogen bonds between hydroxy groups and oxo groups strongly attracted a minus charge on the TOT skeleton. The HOMO energy of the monoanion species was significantly reduced, causing a blue shift of the HOMO-LUMO transition and an anodic shift of the redox potential. In addition, due to the steric repulsion smaller than that of the methoxy group, the hydroxy derivative showed a more planar molecular structure and a strong π-stacking ability.

Prognosis of Immune-related Adverse Events in Patients With Advanced Gastric Cancer Treated With Nivolumab or Pembrolizumab: A Multicenter Retrospective Analysis.

BACKGROUND: Immune-checkpoint inhibitors (ICI), including nivolumab and pembrolizumab, are among the standard treatments for previously treated advanced gastric cancer (AGC). This study aimed to evaluate the frequency of immune-related adverse events (irAEs) and the correlation between irAEs and their efficacy in AGC cases. PATIENTS AND METHODS: Patients were divided into two groups according to irAE occurrence. The frequency of irAEs and the treatment outcome (response rate [RR], progression-free survival [PFS], and overall survival [OS]) were evaluated. The survival rates were evaluated by landmark analysis considering lead-time bias. RESULTS: Among 108 patients who received nivolumab or pembrolizumab, 17 (15.7%) had irAEs. In a 4-week landmark analysis, the RR, median PFS, and median OS were 28.5%, 3.9 months (95% CI=2.8-9.3), and 12.2 months (95% CI=3.8-NA) in patients with irAEs, while 3.0% (2/65), 1.8 months (95% CI=1.4-2.1), and 3.5 months (95% CI, 2.9-5.1) in patients without irAEs, respectively. In multivariate analysis, irAEs were associated with better PFS (HR=2.08, 95% CI=1.34-3.21). CONCLUSION: The occurrence of irAEs was associated with a better clinical outcome of ICIs in patients with AGC.

Effect of Alkyl Chain Length on Charge Transport Property of Anthracene-Based Organic Semiconductors.

Anthracene, a simple planar building block for organic semiconductors, shows strong intermolecular interactions and exhibits strong blue fluorescence. Thus, its derivatives have a great potential to integrate considerable charge carrier mobility and strong emission within a molecule. Here, we systematically studied the influence of alkyl chain length on the crystal structures, thermal properties, photophysical characteristics, electrochemical behaviors, and mobilities for a series of 2,6-di(4-alkyl-phenyl)anthracenes (Cn-Ph-Ants, where n represents the alkyl chain length). Among them, Cn-Ph-Ants (n = 0, 1, 2, and 3) display similar layered herringbone (LHB) packing motifs, which facilitate two-dimensional charge transport and thereby enables high-performance organic field-effect transistors (OFETs). All Cn-Ph-Ants exhibit similar work functions and show strong blue fluorescence with photoluminescence quantum yields (PLQY) of approximately 40% in toluene. In addition, the absolute powder PLQYs of C0-, C2-, C3-, C4-, and C6-Ph-Ants are 24.6, 8.2, 5.7, 10.9, and 8.6%, respectively. Note that the alkyl chain length shows a significant effect on the charge mobilities of Cn-Ph-Ants. Our newly synthesized C1-, C3-, and C4-Ph-Ants show hole mobilities of up to 2.40, 1.34, and 1.00 cm2 V-1 s-1, respectively, with mobilities of 3.40, 1.57, and 0.82 cm2 V-1 s-1 for C0-, C2-, and C6-Ph-Ants, indicating an increasing tendency of mobility with shorter alkyl chain length. This feature is related to the microstructures of the thin films, which reveal the enhanced film order, crystallinity, and grain size with a decrease in the alkyl chain length. Moreover, we theoretically analyze the intermolecular transfer integrals of HOMOs, which increase at T-shaped contacts as the alkyl chain length decreases, which improves the intermolecular charge transport properties, leading to the increases in mobility. Interestingly, the anisotropy of the transfer integral tends to decrease upon substitution with longer alkyl chains, suggesting that alkyl chain adjustments may facilitate isotropic charge transport property in 2,6-alkylated anthracenes.

Small intestinal mucosal injury and its risk factors in patients with gastrointestinal cancer who developed complicated fluoropyrimidine-induced diarrhea.

BACKGROUND: Diarrhea is a common adverse event of fluoropyrimidine-based chemotherapy. However, limited data are available on the frequency and risk factors of complicated chemotherapy-induced diarrhea (CID) and small intestinal mucosal damage. In this current study, we aimed to determine the incidence of complicated CID and mucosal injury among patients with complicated CID receiving fluoropyrimidine via small bowel capsule endoscopy (CE) and determined baseline risk factors associated with complicated CID. METHODS: In total, 536 patients with advanced or recurrent gastrointestinal cancer who received fluoropyrimidine-based chemotherapy were retrospectively analyzed. Diarrhea was evaluated using the Common Terminology Criteria for Adverse Events version 4. Complicated CID was defined according to the American Society of Clinical Oncology guidelines. To evaluate small intestinal mucosal injury in patients with complicated CID, CE was performed. Multivariate analysis was performed to identify risk factors for complicated CID. RESULTS: Total number of 32 (6%) patients developed complicated CID. Complicating symptoms were noted in 25 (78%) patients, with cramping, vomiting, and sepsis being observed in 15 (60%), 8 (32%), and 3 (12%) patients, respectively. Among the 13 patients who underwent CE, 11 (85%) showed abnormal findings. Multivariate analysis revealed that oral fluoropyrimidine administration was a risk factor for complicated CID (odds ratio 2.95; 95% confidence interval 1.06-8.19). CONCLUSIONS: Despite the relatively low incidence of complicated CID, mucosal injury of small intestine was common in patients with complicated fluoropyrimidine-induced diarrhea and oral fluoropyrimidine was an independent risk factor.

[A case of Lemmel syndrome caused by food residue in giant juxtapapillary diverticulum].

A woman in her 70s was admitted to our hospital because of epigastric pain and anorexia. Laboratory evaluations revealed elevated levels of liver transaminases, biliary enzymes, and amylase. CT and MRCP showed dilatation of the bile and pancreatic ducts and a large juxtapapillary diverticulum filled with contents. There were no gallstones or tumors present. Our differential diagnosis included obstruction of the papilla of Vater, so we performed an urgent ERCP. Endoscopic examination showed the juxtapapillary diverticulum filled with food residue;however, we were unable to locate the papilla of Vater. We rinsed out and removed food residue from the diverticulum using a retrieval balloon catheter used for gallstones. After the endoscopic removal of the food residue, the patient's epigastric pain immediately subsided and her cholangitis and pancreatitis improved gradually.

Investigation of the effects of electromagnetic field treatment of hot spring water for scale inhibition using a fibre optic sensor.

Treatment with an electromagnetic field, one of the potential techniques to inhibit scale deposition from water, has the advantage of not requiring the addition of any chemicals. Field tests using a fibre optic sensor were conducted to evaluate the effect that the treatment of hot spring water in Matsushiro, Japan with an electromagnetic field had on calcium carbonate scale formation. The optical response to scale deposition recorded by the fibre optic sensor decreased as a consequence of the application of an electromagnetic field, and the effectiveness of scale formation inhibition depended on the frequency of the electromagnetic field. This evidence was compared with results from changes in scale mass measured using the quartz crystal microbalance (QCM) method. Mass increases of the scale formed on the quartz crystal surface in hot spring water were inhibited by electromagnetic field treatment. These results were verified performing a column flow test, whereby the flow rate of hot spring water through a column was measured.