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Ground-penetrating radar (GPR) is a non-destructive and non-invasive geophysical survey method that has been used to characterize soil volumetric water content (VWC) dynamics. An array antenna GPR system was used to collect nearly seamless, time-lapse multi-offset GPR data during an in-situ infiltration test on sand dunes with limited traces. Because the data volume was significant, an approach was utilized to automatically determine electromagnetic wave velocities from sparse common midpoint (CMP) data using standard velocity analysis, such as semblance analysis. The objective of this study was to develop a methodology that allows one to automatically perform velocity analysis by interpolating sparse CMP data obtained with the array GPR system. The proposed method determined the optimal normal moveout velocity values and the removal range of the F-K zone pass filter that minimized errors between the original and interpolated CMP data using leave-one-out cross-validation (LOOCV). After interpolating the sparse CMP data with the F-K zone pass filter, semblance analysis was used to determine the time-lapse velocity structure of the soil profile during water infiltration. The velocity data were converted to VWC data based on the Topp equation, which relates the soil VWC to the soil dielectric constant. The proposed method was tested using CMP data obtained via numerical simulation and experiments. The VWC profile from the proposed approach matched well with the independently observed VWC profiles obtained from an invasive probe-type soil moisture sensor.

The aim of this study was to determine the proportion of near-miss dispensing errors in hospital pharmacies in Japan. A prospective multi-center observational study was conducted between December 2018 and March 2019. The primary objective was to determine the proportion of near-miss dispensing errors in hospital pharmacy departments. The secondary objective was to determine the predictive factors for near-miss dispensing errors using multiple logistic regression analysis. The study was approved by the ethical committee at The Institute of Medical Sciences, University of Tokyo, Japan. A multi-center prospective observational study was conducted in 20 hospitals comprising 8862 beds. Across the 20 hospitals, we assessed data from 553 pharmacists and 53039 prescriptions. A near-miss dispensing error proportion of 0.87% (n = 461) was observed in the study. We found predictive factors for dispensing errors in day-time shifts: a higher number of drugs in a prescription, higher number of quantified drugs, such as liquid or powder formula, in a prescription, and higher number of topical agents in a prescription; but we did not observe for career experience level for clinical pharmacists. For night-time and weekend shifts, we observed a negative correlation of near-miss dispensing errors with clinical pharmacist experience level. We found an overall incidence of near-miss dispensing errors of 0.87%. Predictive factors for errors in night-time and weekend shifts was inexperienced pharmacists. We recommended that pharmacy managers should consider education or improved work flow to avoid near-miss dispensing errors by younger pharmacists, especially those working night or weekend shifts.

Dysphonia has been reported with anti-angiogenic chemotherapy agents. Dysphonia in patients with cancer receiving chemotherapy tends to be overlooked in clinical practice since it is non-life-threatening. However, it reduces quality of life. Although inhibition of vascular endothelial growth factor receptor is the reported mechanism of dysphonia, it has not been elucidated. We report 6 cases of patients with dysphonia suspected to be due to panitumumab and nivolumab that have not been reported previously. Peripheral edema, a factor in dysphonia, can be seen with aflibercept, bevacizumab, panitumumab, and nivolumab. Therefore, chemotherapy drugs with peripheral edema may be related to dysphonia.

Objectives Patients with hematological cancer receiving chemotherapy have a high risk of thiamine deficiency due to accelerated thiamine usage by tumor cells. Mild or severe thiamine deficiency can lead to varying degrees of neurological symptoms. We evaluated the relationship between thiamine deficiency and neurological symptoms, including mild or nonspecific symptoms, and the influence of chemotherapy on thiamine serum levels in patients with hematological cancer receiving chemotherapy. Materials and Methods We retrospectively identified 42 patients diagnosed with hematological cancer at our hospital, using electronic medical records collected from March 2019 to March 2020. We evaluated the risk factors associated with neurological symptoms (mild-to-severe cognitive impairment, attention impairment, and mood or emotional disorder), the relationship between the presence of neurological symptoms and thiamine serum levels, and changes in thiamine serum levels after chemotherapy. Results Thiamine deficiency was significantly associated with neurological symptoms. The thiamine serum levels in the group with neurological symptoms were significantly lower than those in the group without neurological symptoms. The Wilcoxon rank-sum test showed that thiamine serum levels after chemotherapy were significantly lower than those before administration of chemotherapy. Conclusion Thiamine serum levels in patients with hematological cancer may be used as a reference to maintain neurological status during chemotherapy.

Nondestructive and noninvasive visualization and quantification of dynamic subsurface hydrologic processes are needed. Using a ground-penetrating-radar (GPR) antenna array, time-lapse common-offset gather and common midpoint (CMP) data can be collected by fixing the antenna at a given location when scanning the subsurface. We have determined wetting front depths continuously during a field infiltration experiment by estimating electromagnetic (EM) wave velocities at given elapsed times using GPR antenna array data. A surface GPR antenna array system, consisting of 10 transmitters (Tx) and 11 receivers (Rx), that can scan each Tx-Rx combination in 10 s at a millisecond scale has been used to acquire all 110 Rx-Tx combinations in approximately 1.5 s. The field infiltration experiment has been conducted at an experimental field near the Tottori Sand Dunes in Japan. Using the estimated EM wave velocity from the CMP data, the depth to the wetting front is computed every minute. The estimated wetting front arrival time agrees with the time at which a sudden increase in the moisture sensor output is observed at a depth from 20 cm and below. We determine that time-lapsed CMP data collected with the GPR antenna array system could be used to estimate EM wave velocities continuously during the infiltration. The GPR antenna array is capable of accurate and quantitative tracking of the wetting front.

This study was aimed at assessing the adherence and incorrect drug intake associated with changes in the dosing schedule of raltegravir, the first integrase strand transfer inhibitor, from 400 mg twice a day (BID) to 600 mg × 2 tablets once a day (QD) in human immunodeficiency virus (HIV)-infected patients. Medication adherence over 1 month was evaluated in 25 male patients using the 100-mm visual analog scale (VAS) at the 3-day recall pill count and during pharmacist counseling after the first post-change visit. VAS scores before and after the raltegravir formulation change were compared. Medication adherence increased from 96 ± 4.3 mm (BID) to 100 ± 0.3 mm (QD) (P0.05). The patients exhibited improved medication adherence; however, three patients incorrectly took the drug when the formulation changed. This discovery can be used to facilitate the treatment of HIV-infected patients to increase treatment suitability and safety.

In recent years, the risk of sediment-related disasters has increased due to the increase in heavy rain disasters. Therefore, a technique for more easily diagnosing the internal structure of dikes such as fill dams is desired. We applied machine learning to this task.In this study, we estimated the correspondence between the hydraulic conductivity distribution and the pressure head distribution of the zoned dike using machine learning. The machine learning method is pix2pix which is derived from generative adversarial networks (GAN). Pix2pix learns the relationship between input and output image. Training datasets were generated by using HYDRUS-2D In the HYDRUS-2D simulation, the dike was divided into three zones, and the seepage analysis was performed by changing the hydraulic conductivity of each zone to various values, and the pressure head distribution in the steady state was obtained.In the forward problem, most of the results could be estimated accurately. On the hand, it was difficult to estimate the inverse problem because of the ill-posed problem. In the inverse problem, we were able to improve the results by giving the training data a priori information about the hydraulic conductivity.This approach can be used as a surrogate model for the forward problem and the inverse problem in seepage analysis.

Pancytopenia associated with vitamin B12 and folic acid deficiency has been reported in patients who have undergone total gastrectomy. Therefore, myelosuppression due to chemotherapy following total gastrectomy is considered to be more serious. We encountered three cases of severe thrombocytopenia in patients who received chemotherapy after total gastrectomy. The lowest platelet levels in these patients were 1.7 × 104/mm3, 2.3 × 104/mm3, and 0.9 × 104/mm3, respectively. None of the patients presented with vitamin B12 deficiency, and one patient presented with folic acid deficiency. The association between serum vitamin levels and chemotherapy-related adverse events is controversial. Since folic acid has a shorter half-life (6 hours) and cannot accumulate in the body, unlike vitamin B12 that is stored for a long time in the liver, folic acid deficiency is suspected to be associated with thrombocytopenia induced by post-total gastrectomy chemotherapy. However, serum folic acid levels fluctuate depending on the timing of evaluation and require a few days to evaluate. In conclusion, patients who undergo chemotherapy after total gastrectomy should be monitored for severe thrombocytopenia but serum vitamin B12 levels are not necessarily clinically important. By measuring serum folic acid levels at appropriate times, folic acid deficiency may prove to be a reference for predicting severe thrombocytopenia.

Gastrointestinal cancer and its treatment using fluorouracil-based anticancer agents are risk factors for thiamine deficiency (TD). Therefore, we aimed to determine the prevalence of TD among elderly patients with gastrointestinal cancer undergoing chemotherapy. We retrospectively reviewed the medical records of 12 elderly patients with gastrointestinal cancers who underwent chemotherapy. Median serum thiamine level was 22.5 ng/mL (range, 17 - 42 ng/mL). Four patients (33.3%) exhibited TD (lt; 20 ng/mL). We found that the prevalence of TD among elderly patients with gastrointestinal cancer undergoing chemotherapy was high. For these patients, careful monitoring of thiamine levels is warranted because TD may not produce overt clinical symptoms.

WHAT IS KNOWN AND OBJECTIVE The aim of this study was to clarify the low-density lipoprotein (LDL)-C level achievement rate and detect factors affecting the failed LDL-C achievement rate in patients treated with statins and anti-platelet agents using a large insurance claim database and health check-up data. METHODS Access to a large health insurance claims database, and health check-up data were obtained from Japan Medical Data Center (JMDC) Co. Ltd., Tokyo. The database was searched to identify employed working-age male patients who had started treatment with statin and anti-platelet drugs for the secondary prevention of cardiovascular events. These patients were enrolled in the retrospective cohort study, which included screening at 3 months and observation for 3 years. LDL-C levels were obtained from the annual health check-up data. The achievement rate for LDL-C

To evaluate the variations in the elastic shear modulus G0 of saturated sandy soil during consolidation, undrained cyclic loading and reconsolidation, we performed a series of multiple-phased triaxial tests with measurements of shear wave velocity on specimens having different dry densities. At the same isotropic effective stress, the G0 value during undrained cyclic loading became smaller than that during initial consolidation. For the same effective stress parameter that was found to be relevant to the isotropic and anisotropic stress states, the G0 value at an identical effective stress parameter at isotropic and anisotropic stress states during undrained cyclic loading decreases similarly with an increase in the previous strain amplitude. By reconsolidation to the original effective stress state, the G0 value increased partly due to recovery from the shear-induced damage and partly due to a decrease in the void ratio. The effects of the former factor decreased as the specimen became denser, while the effects of the latter factor increased as the specimen became looser. As a result, compared with the initial value at the end of initial consolidation, the G0 value after reconsolidation of the same specimen became significantly smaller with dense specimens while it became significantly larger with loose specimens.

Although varicella zoster virus (VZV) disease is a common complication after allogeneic hematopoietic cell transplantation (HCT), research into the long-term incidence of VZV disease in adults receiving cord blood transplantation (CBT) has been limited. The objective of this study was to evaluate the incidence, risk factors, and clinical impact of VZV disease after CBT with long-term follow-up in our institution. We retrospectively analyzed the data for 156 adult patients who received single-unit CBT at our institution between 2007 and 2020 and who achieved neutrophil engraftment and survived at least 100 days without recurrence of the underlying disease. VZV disease occurred in 61 patients at a median of 608 days (range, 36 to 4090 days) after CBT. The cumulative incidence of VZV disease was 14% (95% confidence interval [CI], 9% to 20%) at 1 year post-CBT and 40% (95% CI, 31% to 48%) at 5 years post-CBT. Multivariate analysis identified the cessation of antiviral prophylaxis as an independent risk factor for an elevated risk of VZV disease (hazard ratio, 15.65; 95% CI, 6.59 to 37.21; P.001). The cumulative incidence of VZV disease was significantly lower in the long-term antiviral prophylaxis group (who received prophylaxis for approximately 1 year after CBT or to the end of immunosuppressive therapy) compared with the short-term antiviral prophylaxis group (who received prophylaxis for 35 days after CBT) (P = .005). Among the patients who developed VZV disease, the median time to onset of VZV disease was significantly delayed in the long-term antiviral prophylaxis group compared with the short-term antiviral prophylaxis group (694 days versus 130 days; P.001), but the median onset of VZV disease after the cessation of antiviral prophylaxis was not significantly different between the 2 groups (166 days versus 95 days; P = .087). These data demonstrate that the long-term incidence of VZV disease is relatively high in adult patients undergoing CBT. Given that the incidence of VZV disease remained high after the cessation of antiviral prophylaxis, additional interventions, such as recombinant zoster vaccine administration, could be required to prevent VZV disease in long-term adult survivors after CBT.

Objectives FOLFOX is a standard chemotherapy regimen used to treat colorectal cancer. Adverse events associated with FOLFOX treatment include peripheral neuropathy and myelosuppression. This report discusses the case of a 64-year-old man with rectal cancer who developed hyperammonemia and impaired consciousness following initiation of mFOLFOX6 as a postoperative adjuvant therapy. Methods This case study reports on the clinical disease progression of the aforementioned patient. Results Following preoperative chemoradiotherapy, the patient underwent low anterior resection for rectal cancer. mFOLFOX6 was then initiated as postoperative adjuvant therapy. During the 5th cycle of mFOLFOX6 treatment, the patient presented with impaired consciousness and upper extremity convulsions. Blood testing revealed marked hyperammonemia (349 µg/dL (normal range: 12 - 66 µg/dL)). Imaging did not reveal any intracranial lesions that could cause impaired consciousness. The patient recovered within a day after rehydration and BCAA substitution. Conclusion Although impaired consciousness is a rare adverse reaction of FOLFOX, it has a major psychological impact on the patient and his/her family. Hyperammonemia should therefore be considered a potential cause of impaired consciousness during FOLFOX therapy and should be appropriately diagnosed and treated.

Severe oral mucositis caused by chemo- and radio-therapy is a common adverse event in patients with cancer. In this study, we investigated the development of an indomethacin mouth wash(IM-MW)as a novel approach to treat pain due to oral mucositis.We examined the appropriate preparation methods for IM-MW with suitable stability. IM- MW was made from bulk IM, controlled release IM capsules, and IM capsules. Dissolution in water was tested at water temperatures of 70℃, 90℃, and 98℃(n=3), and with a shaking time of 30 or 60s(n=3). We determined the IM concentration in IM-MW by HPLC-UV analysis(n=5)at time points between just after preparation and day 7, to estimate the shelf- life at 4℃ and 25℃.At 70℃, bulk IM did not dissolve, but at 90℃ and 98℃, bulk IM, controlled release IM capsules, and IM capsules all dissolved effectively. Shaking times of 30 and 60s were sufficient to dissolve bulk IM, controlled release IM capsules, and IM capsules. The stability of IM in IM-MW was 98.6±2.8%(bulk), 99.2±6.0%(controlled release capsule), and 98.5±6.0%(capsule)over 7 days at 4℃. However, at 25℃, IM stability in IM-MW decreased to 95.3±1.8% (bulk), 86.1±4.8%(controlled release capsule), and 83.6±1.6%(capsule).In this study, we identified the most suitable method for the preparation of IM-MW(90℃, shaking time of over 30s). IM-MW was stable when stored at 4℃ for at least 7 days after preparation.

Objectives The aim of this retrospective study was to search for risk factors for neurological adverse events in gastrointestinal cancer patients receiving chemotherapy and analyze the relationship between thiamine serum levels and neurological adverse events. Materials and methods This is a single-center retrospective observational study. We enrolled patients who were diagnosed with gastrointestinal cancer at our hospital, for whom we measured the thiamine serum levels. We then performed a multivariate analysis (logistic regression) to identify risk factors for the neurological symptoms in our cohort. We then divided the patients into two groups, with and without neurological symptoms, based on their electronic medical records. By using the Mann-Whitney U-test, we performed a comparative analysis of the thiamine serum levels between the two groups. We also used descriptive statistics to examine the presence/absence of neurological symptoms or other potentially related clinical features in patients with decreased thiamine serum levels. Results The logistic regression analysis detected the decrease in thiamine serum levels as a statistically significant risk factor for neurological symptoms. The analysis of the relationship between the presence/absence of neurological symptoms and thiamine serum levels showed that the thiamine serum levels were significantly lower in the group presenting neurological symptoms. Descriptive statistics showed that all the patients with decreased thiamine serum levels had either cognitive decline, attention decline, or depression symptoms, and most of them were receiving the 5-fluorouracil anticancer drug and showing decreased serum albumin levels. We also observed a slight decrease in serum sodium, vitamin B12, and folate levels. Conclusion When neurological symptoms occur in patients receiving chemotherapy for gastrointestinal cancer, the measurement of thiamine serum levels may become a standard reference for treatment indication.

Background: Clinical evidence of thiamine-related neuropsychiatric symptoms, including the initial stage, is limited because serum thiamine levels tend to be evaluated only for patients who develop severe neuropsychiatric symptoms suspected to be related to severe thiamine deficiency. This study aimed to evaluate the relationship between thiamine decline and neuropsychiatric symptoms, including initial symptoms, and the effect of chemotherapy on serum thiamine levels in gastrointestinal and hematological cancer patients receiving chemotherapy. Method: We retrospectively identified 87 patients who were diagnosed with gastrointestinal and hematological cancers at our hospital. We evaluated the risk factors associated with neuropsychiatric symptoms, including initial symptoms (neuropsychiatric symptoms), the relationship between the presence of neuropsychiatric symptoms and serum thiamine levels, and changes in serum thiamine levels after chemotherapy. Results: Logistic regression analysis identified thiamine decline as a significant factor associated with neuropsychiatric symptoms (p

We describe a case of a patient treated for cognitive dysfunction (CD) with suspected thiamine deficiency (TD). A 74-year-old man with gastric cancer presented with grade 3 diarrhea and grade 1 anorexia. He had been receiving trastuzumab plus tegafur (a chemotherapeutic fluorouracil prodrug), gimeracil, and oteracil (S-1) and oxaliplatin. On admission, cognitive function was assessed with the Hasegawa's Dementia Scale (HDS-R) because he had impaired short-term memory. His thiamine levels increased from 22 to 109 ng/mL after administration of 75 mg of thiamine. Furthermore, the patient's HDS-R score improved from 9 to 22, and cognitive and memory functions improved. TD should be considered in older CD patients receiving oral chemotherapy agents including fluorouracil.

This study aimed to compare and determine the prevalence of drug–drug interaction (DDI) and bleeding rate in atrial fibrillation (AF) patients receiving anticoagulants in a clinical setting. We used large claims data of AF patients obtained from the Japan Medical Data Center. The prevalence of DDIs and cases leading to bleeding events were surveyed clinically relevant DDIs extracted from 1) reported from a spontaneous adverse event reporting system (Japanese Adverse Drug Events Report system; JADER) ≥4 patients; 2) DDIs cited in the package inserts of each anticoagulant (each combination assessed according to “Drug interaction 2015” list; 3) warfarin and quinolone antibiotics DDIs. DDIs were categorized the mechanisms for pharmacokinetic DDI (Cytochrome P450 (CYP) or transporter etc. that modulate blood concentration of anticoagulants)/pharmacodynamic DDI (combination with similar pharmacological actions) or both in the analysis for each patients’ prescriptions obtained from a claims data. AF patients were compared between cases with and without bleeding after administered of anticoagulants. Bleeding was observed in 220/3290 (6.7%) AF patients. The bleeding rate in patients with both pharmacokinetic and pharmacodynamic DDI mechanisms (26.3%) was higher than that in patients with either mechanism (8.6% and 9.2%, respectively) or without DDIs (4.9%). The odds ratio for bleeding in AF patients with both of pharmacokinetic and pharmacodynamic was (7.18 [4.69–11.00], p

Intravenous voriconazole (VRC) is formulated by the incorporation of sulfobutylether-β-cyclodextrin (SBECD), which may accumulate to adversely affect renal function. However, the effect of long-term use of intravenous VRC on renal function is unclear. Our retrospective analysis of data confirmed that worsening of renal function was significantly associated with a cumulative dose of intravenous VRC (≥400 mg/kg), suggesting that a higher cumulative dose of intravenous VRC is a risk factor for renal dysfunction.

Tumor lysis syndrome (TLS) is a life-threatening metabolic complication caused by the rapid breakdown of malignant cells. It is an oncologic emergency and occurs spontaneously after the initiation of chemotherapy for hematological malignancies. Therefore, the management of TLS is important. Rasburicase (RSB) has been shown to be effective for the management of TLS. We retrospectively investigated the optimal administration period of RSB (1 to 7 days) for 38 adult patients with a hematological malignancy who were at high risk for TLS. In all patients, the serum uric acid (sUA) value did not increase beyond the upper limit of normal. Clinical TLS did not occur in any patients. Seven patients were administered a single-dose of RSB and sUA remained within normal limits. These results suggested that single-dose RSB administration was efficacious for Japanese adult patients with hematological malignancies who are at high risk for TLS.

Liposomal amphotericin B (L-AMB) is widely used for empirical or preemptive therapy and treatment of invasive fungal infections after cord blood transplantation (CBT). We retrospectively examined the efficacy and safety of low-dose L-AMB in 48 adult patients who underwent CBT between 2006 and 2017 in our institute. Within the entire cohort, 42 patients (88%) received L-AMB as empirical or preemptive therapy. The median daily dose of L-AMB and the median cumulative dose of L-AMB were 1.20 mg/kg/day (range, 0.62 to 2.60 mg/kg/day) and 30.6 mg/kg (range, 0.7 to 241.5 mg/kg), respectively. The median duration of L-AMB administration was 21.5 days (range, 1 to 313 days). A documented breakthrough fungal infection occurred in 1 patient during L-AMB treatment, and 43 patients (90%) survived for at least 7 days after the end of L-AMB treatment. Grade 3 or higher hypokalemia and hepatotoxicity were frequently observed during L-AMB treatment. However, no patient developed an increase in serum creatinine levels of grade 3 or higher. In univariate analyses using a logistic regression model, a duration of L-AMB treatment of more than 21 days and a cumulative dose of L-AMB of more than 30 mg/kg were significantly associated with nephrotoxicity and grade 3 hypokalemia. These data suggest that low-dose L-AMB may be safe and effective in adult patients undergoing CBT.

A surface array ground penetrating radar (GPR) system was used to estimate the wetting front depth during an infiltration experiment conducted at an experimental field near Tottori Sand Dune, Japan. The array GPR system used in this study consists with 10 transmitting antennas (Tx) and 11 receiving antennas (Rx) aligned horizontally and scans 110 different antenna combinations in less than 1.5 seconds. Common-offset gather (COG) and common mid-point data (CMP) were reconstructed from the time-lapse multi-offset gather (MOG) collected during the infiltration experiment. During the measurement, the array antenna position was fixed to ensure data reproducibility. There have been few studies that used CMP data collected from the array GPR system for further velocity analysis. In this study, electromagnetic (EM) wave velocity structure was estimated from the reconstructed CMP data every 1 minute by fitting the hyperbola equation. Using the estimated EM wave velocity, the depth to the wetting front was computed. The estimated wetting front arrival time agree well with the time when the sudden increase in the soil dielectric constant measured independently with a soil moisture sensor was observed at the depth below 20 cm, This study demonstrates that the array GPR system is capable of tracking the depth to the continuously moving infiltration front.

A Ground Penetrating Radar (GPR) system based on a ground-coupled, densely populated antenna array was used to collect data during an infiltration experiment conducted at a test site near the Tottori Sand Dune, Japan. The antenna array used in this study consists of 10 transmitting antennas (Tx) and 11 receiving antennas (Rx). For this experiment, the system was configured to use all possible Tx-Rx pairings, resulting in a Multi-Offset Gather (MOG) consisting of 110 Tx-Rx combinations. The array was left stationary at a position directly above the infiltration area and data were collected every 1.5 seconds using a time-based trigger. Common-Offset Gather (COG) and Common Mid-Point (CMP) data cubes were reconstructed from the MOG data during post-processing. There have been few studies that used time-lapse CMP data to estimate changes in velocity of propagation. In this study, electromagnetic (EM) wave velocity was estimated heuristically at 1-minute intervals from the reconstructed CMP data through curve fitting, using the hyperbola equation. We then proceeded to calculate the depth of the wetting front. The evolution of the wetting front over time obtain through this method is consistent with the observations from a soil moisture sensor which was placed at a depth below 20 cm. The results obtained in this study demonstrate the ability of such array GPR system to monitor a subsurface dynamic process like water infiltration accurately and quantitatively.

For health monitoring of a building, we need to separate the response of the building to an earthquake from the imprint of soil‐structure coupling and from wave propagation below the base of the building. Seismic interferometry based on deconvolution, where we deconvolve the wave fields recorded at different floors, is a technique to extract this building response and thus estimate velocity of the wave that propagates inside the building. Deconvolution interferometry also allows us to estimate the damping factor of the building. Compared with other interferometry techniques, such as cross‐correlation and cross‐coherence interferometry, deconvolution interferometry is the most suitable technique to monitor a building using earthquake records. For deconvolution interferometry, we deconvolve the wave fields recorded at all levels with the waves recorded at a target receiver inside the building. This receiver behaves as a virtual source, and we retrieve the response of a cut‐off building, a short building that is cut off at the virtual source. Because the cut‐off building is independent from the structure below the virtual source, the technique might be useful for estimating local structure and local damage. We apply deconvolution interferometry to 17 earthquakes recorded during two weeks at a building in Fukushima, Japan, and estimate time‐lapse changes in velocity and normal‐mode frequency. As shown in a previous study, the change in velocity correlates with the change in normal‐mode frequency. We compute the velocities from both traveling waves and the fundamental mode using coda‐wave interferometry. These velocities have a negative correlation with the maximum acceleration of the observed earthquake records.

Because an array ground penetrating radar (GPR) electrically switches any antenna combinations sequentially in milliseconds, both common-offset gather (COG) and multi-offset gather (MOG) data can be acquired almost seamlessly. The main objective of this study was therefore to determine if COG and MOG surveys by array GPR, which allows 110 different antenna combinations, could detect a wetting front during vertical field infiltration. An infiltration experiment was conducted in an experimental field inside Tottori Sand Dune, Japan. Time-lapse radargrams of COG and MOG by array GPR clearly show the wetting front evolution with time. Reflection signals in MOG radargrams agree well with two-way travel times predicted from dielectric constant observed independently with a soil moisture sensor. This study confirms the usefulness of array GPR for monitoring and quantifying the infiltration process in the field.

An artificial groundwater infiltration experiment was conducted in Nagaoka city in Japan, and time-lapse cross-borehole ground-penetrating radar (GPR) data were collected to monitor the infiltration process in the vadose zone using zero-offset profiling (ZOP) mode. The downward migration of induced water was observed as a variation of GPR travel times, which can be transformed into dielectric constant and further converted to volumetric water content. In this paper, we present an effective approach to extract accurate information about the hydrogeologic process in the vadose zone from ZOP data. This approach is based on a least squares inversion method using singular-value decomposition, in which a finite-difference time-domain forward modeling is used for computing electromagnetic wave fields on 2-D cylindrical coordinates. The inversion approach is validated using a synthetic example and applied to the field data. We can successfully estimate the variation of soil water content during infiltration in the Nagaoka site from the reconstructed dielectric constant models. The inversion results show that the saturation information is useful to assess hydrogeologic properties of the test soil zone.

Cross-borehole ground-penetrating radar (GPR) has been widely used to characterize the shallow subsurface and to monitor hydrogeologic processes. To investigate an infiltration process in the vadose zone, an artificial groundwater infiltration test was conducted in Nagaoka, Japan. Time-lapse cross-borehole GPR data were collected using zero-offset profiling (ZOP) mode. The infiltration process was observed as a variation of GPR traveltimes, which can be transformed into a dielectric constant, and further converted to volumetric water content. A standard ZOP analysis, for which all first arrivals are assumed to be direct waves, results in an underestimation of the dielectric constant because of the existence of critically refracted waves. This letter presents an efficient algorithm using the maximum first-cycle amplitude to approximately determine the traveltime of direct arrival, deriving a dielectric constant model more accurately than the standard ZOP analysis from ZOP data. Tests on synthetic and real field data show that the proposed approach is effective in building accurate water content profile without iterative calculations as in the standard ZOP analysis.

The damage caused by an earthquake-induced landslide can generally be classified as either a limited deformation or a catastrophic failure. From an engineering point of view, the latter can be much more dangerous because the sliding mass may continue moving until it collides with another object. If a catastrophic failure occurs near a river, the debris may block the river, causing serious damage to the adjacent area. Therefore, examination of the mechanism of such catastrophic slope failures is important with respect to the mitigation of earthquake disasters in mountainous districts, although numerical modeling of such phenomena is rather difficult. In the present study, a new numerical model is developed to simulate an earthquake-induced catastrophic landslide that occured at a typical dip slope, namely, the Yokowatashi Landslide in Japan. In this case, the upper part of the bedrock on the planer tectonic dip surface slid more than 70 m. Only shear-strength degradation at the bedding plane could cause such a long-distance traveling failure. To investigate the strain-softening characteristics of the materials that filled the bedding plane, a series of laboratory tests involving undisturbed block samples was performed. The measured stress-displacement relationships under cyclic loading were numerically modeled as a newly proposed elasto-plastic constitutive model to be used in numerical simulations of landslide, based on the dynamic finite element method. The observed phenomena were appropriately simulated by the proposed method. The mechanism of catastrophic failure is discussed in detail in this paper in order to clarify the relationships between the strain-softening characteristics and the global slope stability. Our newly proposed method to evaluate the possibility of a catastrophic failure was applied to the landslide, and the moment when the slope becomes unstable was able to be predicted. The results confirm that the proposed method can predict the catastrophic failure of a slope.

砂質土地盤における浅層領域での不飽和浸透挙動の計測方法として，地表設置型の地中レーダ（GPR）を用いた方法を提案し，原位置不飽和浸透試験を実施した結果に基づいて，その適用性および有用性について述べている．自然乾燥状態にある均質な砂丘砂地盤において，一定量の散水を行って地盤内に断面2次元不飽和浸透流を発生させ，その浸潤前線の非定常挙動をGPRプロファイル測定によって地表面から非破壊状態で計測を行った．GPRによって測定された浸潤前線の非定常挙動を浸透流解析手法による数値シミュレーションおよび土中水分量計測データと比較した結果，それらには一致が認められた．

Ground-penetrating radar is a useful tool for civil and environmental engineering fields because of its high resolving power and non-destructive measurements. This paper presents a method of full-waveform inversion of borehole radar data for imaging permittivity structures. The inversion algorithm is based on a conjugate gradient search for the minimum of an error functional relating to the difference between measured and predicted data. A small model perturbation in the functional can be efficiently calculated by propagating the data error back into the model in reverse time and correlating the field generated by the back-propagation with the corresponding incident field at each point. A finite difference time domain (FDTD) method is used for solving Maxwell’s equations to obtain incident electromagnetic wavefields. Back-propagated wavefields satisfy adjoint Maxwell’s equations, which are stable in reverse time and can be solved by the same FDTD scheme. The imaging scheme is applied to crosshole radar configuration, thereby demonstrating its capability to reconstruct permittivity structures. Tests on a two-dimensional synthetic model produce good images of target scatterers and show stable convergence.

2004年の新潟県中越地震では中山間地における多数の斜面崩壊が発生した。二次元動的弾塑性有限要素法によりある流れ盤斜面の崩壊を再現した事例を報告する。このような大規模崩壊を再現するために, 不撹乱ブロック試料による繰返し直接せん断試験に基づいて, 層理面に介在する薄い砂層の繰返し載荷時のひずみ軟化特性が検討された。その結果, 観測された現象が精度良く再現され, 長距離移動型の崩壊が層理面のひずみ軟化挙動により誘引されることが示唆された。

新潟県長岡市の段丘礫層を対象にして行われた地下水人工涵養試験において，浸透マスからの涵養過程を，孔井間地中レーダによってモニタリングした。孔井間地中レーダの等深度プロファイルにおける走時とトップの式による体積含水率の推定をもとに，浸透マスからの浸潤速度や水分増加量等の不飽和帯にける涵養過程を定量的に評価した。コアサンプルから求めた体積含水率および涵養試験時における浸透量といった直接的な測定値との比較によってその妥当性を検証した。また土層は均一ではないため，細粒分が多く透水性の低い浅層の地盤が水理学的な抵抗層のように浸透量を制限し，下層の水分上昇を抑制している状況が推察された。孔井間地中レーダは，地下水人工涵養における不飽和帯での涵養過程の定量的評価に有効と考えられる。

任意の深度区間で地下水水頭や流動量, 水質の測定を行うために, 5%の開孔率をもち, 1m毎に遮断帯を備えた保孔管を使用した観測井を施工した。水圧測定・採水用ゾンデは保孔管内部を区切るために5段のゴムパッカーを備えている。静岡県内の地すべり地の試験孔における測定では, 孔内水位以深の地下水水圧は静水圧分布より低い部分があり, また, 孔内水位以上の深度で正水圧が発生していた。降雨時の深さごとの水頭変化をとらえることができた。パッカーを装着した小型流量計ゾンデを使用して, 孔内鉛直流動量を精密に測定できる。パッカーを使用して深度別に採水した孔内水の酸化還元電位と電導度は, パッカーを使用しない場合より深度による違いが明瞭であった。本方式の試験孔では全深度を対象とした検層が可能である。地すべり斜面のような複雑な構造の地層で地下水の水頭や水質を評価するためには, 必要な深度毎に測定できる方法によることが必要である。

琉球石灰岩の分布地域において地下水の挙動を非破壊で明らかにすることを目的として，比抵抗法2次元探査の繰り返しによる比抵抗モニタリングを行った。約2時間毎に36回測定した2極法データは，見かけ比抵抗断面図上では明瞭な変化を示さない。しかし，ノイズデータを除去した後の測定断面毎の見かけ比抵抗変化率平均値は，約7％の幅で24時間及び12時間程度の周期の変化を示した。これらの変化は近傍の潮位推算値における日潮不等パターンと逆位相で一致した。さらに差トモグラフィ解析により，主な比抵抗変化部は潮汐により地下水面変動が生じている地下水面付近であることが把握できた。以上より，島嶼・沿岸地域で問題となる塩水化した地下水の挙動を把握する上で，比抵抗モニタリング法の有効性が示された。

Numerous natural or artificially embanked slope failures were caused by the 2004 Niigata-ken Chuetsu Earthquake. Characteristics of large scale natural slope failures that occurred at folding hills, river terraces, etc, were classified from a geometric structural view point. It was noted that surface failures occurred at steep cliffs and landslides occurred at gently slanting dip slopes. The cause of a landslide in a dip slope at Yokowatashi, Ojiya city was analytically investigated based on cyclic shear test results of the laminar sand at the bedding plane. This study revealed that the safety factor of the slope stability became momentarily smaller than 1.0 several times during the earthquake due to the small undrained shear strength of the tuff sand seam and the landslide behavior was simulated by an elasto-plastic dynamic finite element analysis where the strength decrease of the sand seam with increasing number of cycles was taken into consideration. The cause of destructive damage of a school building at Nagaoka National College of Technology (NNCT) was next examined by another elasto-plastic dynamic FEM. From the analysis results, it was confirmed that the building was pulled and twisted by the landslide of the bank shotcrete accompanied with pile fracture.