Safety and efficacy of acalabrutinib and obinutuzumab in treatment-naive chronic lymphocytic leukemia: a Japanese phase 1 study.

This report focuses on part 3 of a multicenter, open-label, phase 1 study (NCT03198650) assessing the safety, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of acalabrutinib plus obinutuzumab in Japanese patients with treatment-naive (TN) chronic lymphocytic leukemia (CLL). Ten patients were included; median age was 68 years. With a median treatment duration of 27.2 months, treatment-emergent adverse events (AEs) occurred in all patients (grade ≥3, 70%), and the most common AEs were anemia and headache (40% each). One patient had a grade 4 AE of neutropenia (the only dose-limiting toxicity). PK results suggested no marked effects of concomitant obinutuzumab treatment on the exposure of acalabrutinib. PD assessment indicated that combination therapy provided >98% Bruton tyrosine kinase (BTK) occupancy. Overall response rate (ORR) was 100% with median duration of response (DoR) and median progression-free survival (PFS) not reached. Treatment with acalabrutinib plus obinutuzumab was generally safe and efficacious in adult Japanese patients with TN CLL.

Candidate tumor-specific CD8+ T cell subsets identified in the malignant pleural effusion of advanced lung cancer patients by single-cell analysis.

Isolation of tumor-specific T cells and their antigen receptors (TCRs) from malignant pleural effusions (MPE) may facilitate the development of TCR-transduced adoptive cellular immunotherapy products for advanced lung cancer patients. However, the characteristics and markers of tumor-specific T-cells in MPE are largely undefined. To this end, to establish the phenotypes and antigen specificities of CD8+ T cells, we performed single-cell RNA and TCR sequencing of samples from three advanced lung cancer patients. Dimensionality reduction on a total of 4,983 CD8+ T cells revealed 10 clusters including naïve, memory, and exhausted phenotypes. We focused particularly on exhausted T cell clusters and tested their TCR reactivity against neoantigens predicted from autologous cancer cell lines. Four different TCRs specific for the same neoantigen and one orphan TCR specific for the autologous cell line were identified from one of the patients. Differential gene expression analysis in tumor-specific T cells relative to the other T cells identified CXCL13, as a candidate gene expressed by tumor-specific T cells. In addition to expressing CXCL13, tumor-specific T cells were present in a higher proportion of T cells co-expressing PDCD1(PD-1)/TNFRSF9(4-1BB). Furthermore, flow cytometric analyses in advanced lung cancer patients with MPE documented that those with high PD-1/4-1BB expression have a better prognosis in the subset of 57 adenocarcinoma patients (p = .039). These data suggest that PD-1/4-1BB co-expression might identify tumor-specific CD8+ T cells in MPE, which are associated with patients' prognosis. (233 words).

Relationships between obsessive-compulsive disorder and the big five personality traits: A meta-analysis.

Although several studies have examined the relationships between obsessive-compulsive disorder (OCD) and the Big Five personality traits (i.e., neuroticism, extraversion, openness, agreeableness, and conscientiousness), the results have been inconsistent. Therefore, this meta-analysis comprehensively examined the relationships between OCD and these traits. In total, 23 studies (29 independent datasets) with 30,138 participants were analyzed. The pooled effect size was 0.34 (95% confidence interval [CI]: 0.28, 0.40) for neuroticism, -0.14 (95% CI: -0.18, -0.10) for extraversion, -0.04 (95% CI: -0.09, 0.02) for openness, -0.10 (95% CI: -0.16, -0.04) for agreeableness, and -0.03 (95% CI: -0.11, 0.05) for conscientiousness, indicating that OCD was associated with higher scores for neuroticism and lower scores for extraversion and agreeableness. Meta-regression and subgroup analyses indicated that heterogeneity was mainly due to differences in sample types and OCD measurement instruments. Sensitivity analysis showed that the results of the meta-analysis were robust. Overall, neuroticism was a maladaptive trait, whereas extraversion and agreeableness were adaptive traits for OCD. Although the results could be sample- and instrument-specific, our findings may inform preventions and interventions for OCD symptoms.

Distal gastrectomy and Roux-en-Y reconstruction for refractory reflux esophagitis after proximal gastrectomy and esophagogastric anastomosis reconstruction.

Refractory gastroesophageal reflux disease can develop after proximal gastrectomy and esophagogastrostomy. We introduce a new method that combines distal gastrectomy and Roux-en-Y reconstruction to treat refractory reflux esophagitis in patients who have undergone proximal gastrectomy and esophagogastric anastomosis reconstruction. This novel method may be useful not only for alleviating the symptoms of gastroesophageal reflux disease but also for preventing future esophageal malignancies arising from long-term reflux esophagitis.

Application of anti-vascular endothelial growth factor antibody restores the function of saliva secretion in a type 2 diabetes mouse model.

OBJECTIVES: Xerostomia, a common complication of type 2 diabetes, leads to an increased risk of caries, dysphagia, and dysgeusia. Although anti-vascular endothelial growth factor (VEGF) antibodies, such as ranibizumab (RBZ), have been used to treat diabetic retinopathy, their effects on the salivary glands are unknown. This study evaluated the effects of RBZ on salivary glands to reduce inflammation and restore salivary function in a mouse model of type 2 diabetes. METHODS: Male KK-Ay mice with type 2 diabetes (10-12 weeks old) were used. The diabetes mellitus (DM) group received phosphate-buffered saline, while the DM + RBZ group received an intraperitoneal administration of RBZ (100 µg/kg) 24 h before the experiment. RESULTS: Ex vivo perfusion experiments showed a substantial increase in salivary secretion from the submandibular gland (SMG) in the DM + RBZ group. In addition, the mRNA expression levels of TNF-α and IL-1ß were considerably lower in this group. In contrast, those of aquaporin 5 were substantially higher in the DM + RBZ group, as revealed by quantitative reverse transcription PCR. Furthermore, the number of lymphocyte infiltration spots in the SMG was notably lower in the DM + RBZ group. Finally, intracellular Ca2+ signaling in acinar cells was considerably higher in the DM + RBZ group than that in the DM group. CONCLUSION: Treating a type 2 diabetic mouse model with RBZ restored salivary secretion through its anti-inflammatory effects.

Comparative Efficacy and Acceptability of Treatment Strategies for Antipsychotic-Induced Akathisia: A Systematic Review and Network Meta-analysis.

BACKGROUND: Antipsychotics are the treatment of choice for schizophrenia, but they often induce akathisia. However, comparative efficacy of treatment strategies for akathisia remains unclear. DESIGN: We performed a systematic review and network meta-analyses (PROSPERO CRD42023450720). We searched multiple databases on July 24, 2023. We included randomized clinical trials comparing 1 or more treatment strategies for antipsychotic-induced akathisia against each other or control conditions. We included adults with schizophrenia or other psychiatric disorders treated with antipsychotics. The primary outcome was akathisia severity at posttreatment. Secondary outcomes included akathisia response, all-cause dropout, psychotic symptoms, and long-term akathisia severity. We synthesized data in random effects frequentist network meta-analyses and assessed confidence in the evidence using CINeMA. RESULTS: We identified 19 trials with 661 randomized participants (mean age 35.9 [standard deviation 12.0]; 36.7% [195 of 532] women). No trials examined dose reduction or switching of antipsychotics. Findings suggested 5-HT2A antagonists (k = 6, n = 108; standardized mean difference [SMD] -1.07 [95% confidence interval, -1.42; -0.71]) and beta-blockers (k = 8, n = 105; SMD -0.46 [-0.85; -0.07]) may improve akathisia severity, but confidence in the evidence was deemed low. We also found that benzodiazepines (k = 2, n = 13; SMD -1.62 [-2.64; -0.59]) and vitamin B6 (k = 3, n = 67; SMD -0.99 [-1.49; -0.50]) might also be beneficial, but confidence in the evidence was very low. Analyses of secondary outcomes did not provide additional insights. CONCLUSIONS: Our findings suggest that 5-HT2A antagonists, beta-blockers, and with a lesser certainty, benzodiazepines, and vitamin B6 might improve akathisia. Given the low to very low confidence in the evidence of add-on agents and the absence of evidence of their long-term efficacy, careful consideration of side effects is warranted. These recommendations are extremely preliminary and further trials are needed.

Clinical Impact of a Local Triage System Using the Emergent Large Vessel Occlusion Screen with a Rotation System of Thrombectomy-Capable Hospitals.

Objective: Early intervention with mechanical thrombectomy (MT) is expected to improve the functional outcome in patients with large vessel occlusion (LVO); however, a method for the effective detection of these patients in a prehospital setting and early transport to MT-capable hospitals has not been established. This study aimed to analyze the clinical impact and diagnostic performance of the emergent large vessel occlusion (ELVO) screen and its influence on the transportation time. Methods: The emergency medical services (EMS) in one of the secondary medical areas in Akita, Japan, introduced a prehospital triage system employing an ELVO screen and a rotation system of three MT-capable hospitals on December 1, 2021. Patients who were transferred to each of the three hospitals involved in the rotation system according to a predefined priority list from December 2021 to November 2022 were included in the triage group. Patients who underwent MT in the three hospitals before the introduction of the triage system were assigned to the pre-triage group. We compared the transportation time parameters between the two groups and analyzed the performance of the ELVO screen for the diagnosis of LVOs. This study was approved by the institutional review boards of all three hospitals. Results: Time parameters were compared between the 37 and 42 patients who underwent MT and had detailed data in the triage (n = 351) and pre-triage (n = 43) groups, respectively. The time from door to puncture tended to decrease in the triage group in all hospitals, with one hospital showing a statistically significant shortening of 14 min (p = 0.018). In the triage group, 209 ELVO screen-positive patients were present, with 60 (28.7%) of these having LVO. The sensitivity, specificity, positive and negative predictive values, and area under the curve of the ELVO screen to detect LVO under the present triage system were 87.0%, 47.2%, 28.7%, 93.7%, and 0.671, respectively. Conclusion: The present study demonstrated that the introduction of a triage system may have shortened the time required for MT. ELVO screen may be considered a useful marker for screening LVO in prehospital settings in terms of the sensitivity and negative predictive value; however, further improvement may be necessary to reduce the rate of false positive results.

Spinal intradural pseudocyst formation in central nervous system superficial siderosis.

The figure shows tissue samples taken from three previous cases, revealing the cause of hemosiderin deposition in the central nervous system because of superficial siderosis.

Novel Insights Into the International Association for the Study of Lung Cancer Grading System for Lung Adenocarcinoma.

The new grading system for lung adenocarcinoma proposed by the International Association for the Study of Lung Cancer (IASLC) defines prognostic subgroups on the basis of histologic patterns observed on surgical specimens. This study sought to provide novel insights into the IASLC grading system, with particular focus on recurrence-specific survival (RSS) and lung cancer-specific survival among patients with stage I adenocarcinoma. Under the IASLC grading system, tumors were classified as grade 1 (lepidic predominant with <20% high-grade patterns [micropapillary, solid, and complex glandular]), grade 2 (acinar or papillary predominant with <20% high-grade patterns), or grade 3 (≥20% high-grade patterns). Kaplan-Meier survival estimates, pathologic features, and genomic profiles were investigated for patients whose disease was reclassified into a higher grade under the IASLC grading system on the basis of the hypothesis that they would strongly resemble patients with predominant high-grade tumors. Overall, 423 (29%) of 1443 patients with grade 1 or 2 tumors classified based on the predominant pattern-based grading system had their tumors upgraded to grade 3 based on the IASLC grading system. The RSS curves for patients with upgraded tumors were significantly different from those for patients with grade 1 or 2 tumors (log-rank P < .001) but not from those for patients with predominant high-grade patterns (P = .3). Patients with upgraded tumors had a similar incidence of visceral pleural invasion and spread of tumor through air spaces as patients with predominant high-grade patterns. In multivariable models, the IASLC grading system remained significantly associated with RSS and lung cancer-specific survival after adjustment for aggressive pathologic features such as visceral pleural invasion and spread of tumor through air spaces. The IASLC grading system outperforms the predominant pattern-based grading system and appropriately reclassifies tumors into higher grades with worse prognosis, even after other pathologic features of aggressiveness are considered.

Analysis of Genetic Structure and Genetic Diversity in Japanese Grey-Headed Lapwing Population Using mtDNA.

The grey-headed lapwing (Vanellus cinereus) is a wading species in East Asia. However, examples of regional population dynamics and genetic research are limited. To reconsider the natural history and current status of the grey-headed lapwing in Japan, we analyzed the genetic diversity of the Japanese grey-headed lapwing population. We collected 77 grey-headed lapwing samples from 12 locations across Japan during the breeding season and three individuals during the wintering season and extracted DNA; 496-bp sequences of the ND2, which form part of the mitochondrial DNA, were determined for genetic analysis of the population. Consequently, 10 haplotypes were detected in 80 individuals, and 67 individuals, 84% of the total, shared two haplotypes, namely Vc1 and Vc2. Furthermore, the results showed that the prevalence of Vc1 was higher mainly in northern Japan, while that of Vc2 was higher mainly in southern Japan. Genetic diversity analysis showed that the overall haplotype diversity in Japan was 0.617, which is not particularly low. The sequence of Vc1 was exactly the same as that of grey-headed lapwing in China. Our study revealed the genetic structure of the grey-headed lapwing, suggesting that as the grey-headed lapwing expanded its distribution area into southern Japan, many Vc2-positive individuals migrated southward, resulting in a higher detection rate of Vc2 in southern Japan.

Marital status after colorectal surgery in familial adenomatous polyposis: a nationwide multicenter study in Japan.

BACKGROUND: Patients with familial adenomatous polyposis (FAP) experience psychological and social challenges concerning future events such as marriage and childbirth alongside the medical risks of colorectal cancer (CRC) and FAP-related disease. We retrospectively investigated the rate of marriage and childbirth postoperatively in Japanese patients with FAP. METHODS: We included 161 patients who had colorectal surgery and reported marital status from a national survey of 35 Japanese institutions. Participants were classified according to marital status: married before colectomy (80 patients), married after colectomy (13 patients), and unmarried (68 patients). RESULTS: The marriage rate for all 161 patients (57.8%, standardized ratio 0.95, 95% confidence interval [CI] 0.76-1.14) was comparable to that in the general Japanese population (57.1%). The marriage rate among the 81 patients who were unmarried before colectomy was low (16.0%); however, the standardized marital ratio (0.75, 95% CI 0.34-1.15) was not significantly lower than that of the general population. In multivariable logistic regression, younger age (born after 1980, odds ratio [OR] 0.12, p < 0.001) and genetic testing (OR 4.06, p = 0.001) were associated with postoperative marriage. Seventy-one percent of patients with FAP who married after colectomy became pregnant and achieved delivery. CONCLUSIONS: The marriage rate of patients with FAP was comparable to that of the general population whereas the rate after colectomy was low among patients with FAP. However, in patients with FAP, colorectal surgery itself may not lead to negative consequences in terms of fecundity.

Effect of Heparan Sulfate on Vasculogenesis and Dentinogenesis of Dental Pulp Stem Cells.

INTRODUCTION: Heparan sulfate (HS) is a major component of dental pulp tissue. We previously reported that inhibiting HS biosynthesis impedes endothelial differentiation of dental pulp stem cells (DPSCs). However, the underlying mechanisms by which exogenous HS induces DPSC differentiation and pulp tissue regeneration remain unknown. This study explores the impact of exogenous HS on vasculogenesis and dentinogenesis of DPSCs both in vitro and in vivo. METHODS: Human-derived DPSCs were cultured in endothelial and odontogenic differentiation media and treated with HS. Endothelial differentiation of DPSCs was investigated by real-time polymerase chain reaction and capillary sprouting assay. Odontogenic differentiation was assessed through real-time polymerase chain reaction and detection of mineralized dentin-like deposition. Additionally, the influence of HS on pulp tissue was assessed with a direct pulp capping model, in which HS was delivered to exposed pulp tissue in rats. Gelatin sponges were loaded with either phosphate-buffered saline or 101-102 µg/mL HS and placed onto the pulp tissue. Following a 28-day period, tissues were investigated by histological analysis and micro-computed tomography imaging. RESULTS: HS treatment markedly increased expression levels of key endothelial and odontogenic genes, enhanced the formation of capillary-like structures, and promoted the deposition of mineralized matrices. Treatment of exposed pulp tissue with HS in the in vivo pulp capping study induced formation of capillaries and reparative dentin. CONCLUSIONS: Exogenous HS effectively promoted vasculogenesis and dentinogenesis of DPSCs in vitro and induced reparative dentin formation in vivo, highlighting its therapeutic potential for pulp capping treatment.

Effectiveness and safety of enzalutamide and apalutamide in the treatment of patients with non-metastatic castration-resistant prostate cancer (nmCRPC): a multicenter retrospective study.

OBJECTIVE: Phase III clinical trials demonstrated the efficacy of enzalutamide and apalutamide in patients with non-metastatic castration-resistant prostate cancer (nmCRPC) and PSA doubling time ≤10 months. Although these drugs have been shown to vary in their adverse event (AE) profiles, the differences in their efficacy profiles remain to be evaluated. Therefore, this retrospective study was conducted to evaluate the efficacy of these drugs in patients with nmCRPC. METHODS: This study evaluated 191 patients with nmCRPC treated with enzalutamide (n = 137) or apalutamide (n = 54) in the first-line setting at Jikei University Hospital or its affiliated hospitals between May 2014 and November 2022. Endpoints were defined as oncological outcomes (i.e., PSA response, PFS, PSA-PFS, MFS, CSS, and OS) and AEs. RESULTS: No significant differences were noted in patient backgrounds between the two groups. Patients exhibiting a maximum PSA response of >50% and >90% accounted for 74.5% and 48.9% of patients in the enzalutamide group, and 75.9% and 42.6% of patients in the apalutamide group, respectively, with no significant difference between the groups. The median PSA-PFS was 10 months in the enzalutamide group but not in the apalutamide group, with no significant difference between the groups (P = 0.48). No significant differences were observed in MFS, CSS, or OS between the groups. Patients reporting AEs of all grades and grade 3 or higher accounted for 56.2% and 4.3% of those in the enzalutamide group and 57.4% and 7.4% of those in the apalutamide group, respectively. The most common AE was fatigue (26.3%) in the enzalutamide group and skin rash (27.8%) in the apalutamide group. CONCLUSION: In this retrospective study of their efficacy and safety, enzalutamide and apalutamide were shown to exhibit comparable oncological outcomes but quite different AE profiles, suggesting that their differential use may be warranted based on these findings.

Novel wireless laser doppler flowmeter-based investigation of earlobe vascular dynamics in cardiopulmonary exercise testing.

[Purpose] A new wireless laser Doppler blood flowmeter has facilitated easier, more stable measurement of skin perfusion during exercise. However, earlobe blood flow during the cardiopulmonary exercise test remains unascertained. This study aimed to clarify the characteristics of earlobe blood flow during incremental exercise load in healthy individuals. [Participants and Methods] Among 25 healthy males (age 23.6 ± 2.5 years), cycle ergometer-based symptom-limited cardiopulmonary exercise test, after 4 minutes of rest, was conducted with a 4-minute 20W warm-up and a continuous 2W-increase in the work rate every 6 seconds; earlobe blood flow was measured using a wireless laser Doppler blood flowmeter. [Results] Compared with that at rest, earlobe blood flow increased significantly from 50% of exercise peak intensity to a maximum of 1.7 times, but decreased immediately after exercise. The earlobe blood flow %change did not significantly correlate with hemodynamic parameters and its inflection point 36.4% Loadpeak was significantly lower than the anaerobic metabolic threshold 58.1% Loadpeak. [Conclusion] In healthy participants, earlobe blood flow during cardiopulmonary exercise test increased gradually with low-intensity exercise from approximately 1.5 times the resting rate and approached the anaerobic metabolic threshold with a maximum of 1.7 times the resting earlobe blood flow, but decreased quickly after exercise.

H3.1/3.2 regulate the initial progression of the gene expression program.

In mice, transcription from the zygotic genome is initiated at the mid-one-cell stage, and occurs promiscuously in many areas of the genome, including intergenic regions. Regulated transcription from selected genes is established during the two-cell stage. This dramatic change in the gene expression pattern marks the initiation of the gene expression program and is essential for early development. We investigated the involvement of the histone variants H3.1/3.2 in the regulation of changes in gene expression pattern during the two-cell stage. Immunocytochemistry analysis showed low nuclear deposition of H3.1/3.2 in the one-cell stage, followed by a rapid increase in the late two-cell stage. Where chromatin structure is normally closed between the one- and two-cell stages, it remained open until the late two-cell stage when H3.1/3.2 were knocked down by small interfering RNA. Hi-C analysis showed that the formation of the topologically associating domain was disrupted in H3.1/3.2 knockdown (KD) embryos. Promiscuous transcription was also maintained in the late two-cell stage in H3.1/3.2 KD embryos. These results demonstrate that H3.1/3.2 are involved in the initial process of the gene expression program after fertilization, through the formation of a closed chromatin structure to execute regulated gene expression during the two-cell stage.

Global discharge of microplastics from mechanical recycling of plastic waste.

The increasing production of plastic products and generation of plastic waste have had increasingly negative environmental impacts. Although recycling could reduce plastic pollution, microplastics can be generated during the process of crushing plastic products during mechanical recycling. We conducted crushing tests with 13 different plastics and documented the size distribution of particles generated. We then estimated the discharge of microplastics associated with recycling and their removal in wastewater treatment plants. We estimated that the global discharge of microplastics would increase from 0.017 Mt in 2000 to 0.749 Mt in 2060. Although mechanical recycling was estimated to account for 3.1% of the total emissions of microplastics for 2017, discharges of microplastics from plastic recycling may increase, even if plastic pollution from well-known sources decreases. Non-OECD (Organization for Economic Cooperation and Development) Asia could be a major discharging region and would play a vital role in reducing discharges of microplastics. Reduction of the discharge of microplastics will require less use of plastic products and upgrading wastewater treatment in many countries.

Effects of Sodium Hypochlorite Concentration and Application Time on Bacteria in an Ex Vivo Polymicrobial Biofilm Model.

INTRODUCTION: In endodontic treatment, it is important to remove or inactivate biofilms in the root canal system. We investigated the effects of different concentrations and application times of sodium hypochlorite (NaOCl) on the viability of bacteria in ex vivo polymicrobial biofilms of different maturation levels. METHODS: Polymicrobial biofilms were prepared from dental plaque samples and grown for 1, 2, and 3 weeks under anaerobic conditions on collagen-coated hydroxyapatite discs as an ex vivo biofilm model. The biofilms were then exposed to NaOCl at concentrations ranging from 0.1% to 2% for 1 or 3 minutes. The control group was exposed to sterile distilled water. Viability staining was performed and examined by confocal laser scanning microscopy to determine the percentage of biofilm bacteria killed by NaOCl. Scanning electron microscopy was also performed to visually examine the biofilms. RESULTS: Application of NaOCl at 0.5%-2% for both 1 and 3 min killed significantly more bacteria when compared to the controls (P < .05). Cell viability tended to be lower after the application of NaOCl for 3 minutes than that for 1 minute. CONCLUSIONS: Our experiments using an ex vivo model showed that within the range of 0.1%-2% of NaOCl, higher NaOCl concentrations and longer application times were more effective in killing biofilm bacteria, and that mature biofilms were more resistant to NaOCl than younger biofilms.

Compensatory expansion of the right middle lobe: volumetric and functional analysis of the changes after right upper or lower lobectomy.

The right middle lobe often poorly expands after right upper lobectomy. Postoperative pulmonary function may be inferior after right upper lobectomy than after right lower lobectomy due to poor expansion of the middle lobe. This study examined the difference in the postoperative right middle lobe expansion and pulmonary function between right upper and right lower lobectomy. Patients who underwent right upper or right lower lobectomy through video-assisted thoracic surgery (n = 82) were enrolled in this retrospective study. Pulmonary function tests and computed tomography were performed preoperatively and at 1 year postoperatively. Using three-dimensional computed tomography volumetry, the preoperative and postoperative lung volumes were measured, and the predicted postoperative forced expiratory volume in 1 s was calculated. Middle lobe volume ratio (i.e., ratio of the postoperative to the preoperative middle lobe volume) and the postoperative forced expiratory volume in 1 s ratio (i.e., ratio of the measured to the predicted postoperative forced expiratory volume in 1 s) were compared between right upper and right lower lobectomy. Compared with the patients who underwent right upper lobectomy (n = 50), those who underwent right lower lobectomy (n = 32) had significantly higher middle lobe volume ratio (1.15 ± 0.32 vs. 1.63 ± 0.52, p < 0.001) and postoperative forced expiratory volume in 1 s ratio (1.12 ± 0.12 vs. 1.19 ± 0.13, p = 0.010). The right middle lobe showed more expansion and better recovery of postoperative pulmonary function after right lower lobectomy than after right upper lobectomy.

Biomass conversion and radiocaesium (Rad-Cs) leaching behaviors of radioactive grass in anaerobic wet fermentation systems: Effects of pre-treatments.

Persistent concerns regarding environmental hazards arise from the difficulty in disposing of radioactive plant-based wastes originating from the nuclear accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) in Japan in 2011. In this study, three anaerobic digestion (AD) strategies were proposed: Sole anaerobic wet fermentation, and wet fermentations with either alkaline-heat or ultrasonic pre-treatment, which were employed for long-term anaerobic treatment of a genuine radioactive grass stemming from the FNPP accident. The objectives of this work are to investigate the effects of pre-treatments on biomass conversion efficiency and to gain insight into the leaching behavior of radiocaesium (Rad-Cs) within AD processes. Experimental results indicate that by introducing alkaline-heat and ultrasonic pre-treatments to AD systems, the removal efficiencies of total solids (TS) from the raw grass increased by 60.8 % and 42.5 %, respectively, compared to sole wet fermentation. Pre-treatments have been shown to enhance the stability of AD systems, both in terms of enhancing methane production and mitigating pH fluctuations triggered by the accumulation of organic acids. Remarkably, even though the Rad-Cs leaching rate was highest when the AD system was fed with the alkaline-heat pre-treated grass, it remained unsatisfactory at only 5.77 %. We inadvertently isolated a soil-like component from the raw grass, and analyzed both its proportion in the raw grass and the radioactivity intensity. The results indicate that although the soil constituted only 9.51 % TS of the raw grass, it accounted for a significant 81.35 % of the total radioactivity. The soil, which has a pronounced affinity for ionic Cs, being mixed into the raw grass, was identified as the primary factor limiting the leaching efficiency of Rad-Cs throughout both the pre-treatment and wet fermentation phases.