Specifically adsorbed ferrous ions modulate interfacial affinity for high-rate ammonia electrosynthesis from nitrate in neutral media.

The electrolysis of nitrate reduction to ammonia (NRA) is promising for obtaining value-added chemicals and mitigating environmental concerns. Recently, catalysts with high-performance ammonia synthesis from nitrate has been achieved under alkaline or acidic conditions. However, NRA in neutral solution still suffers from the low yield rate and selectivity of ammonia due to the low binding affinity and nucleophilicity of NO3-. Here, we confirmed that the in-situ-generated Fe(II) ions existed as specifically adsorbed cations in the inner Helmholtz plane (IHP) with a low redox potential. Inspired by this, a strategy (Fe-IHP strategy) was proposed to enhance NRA activity by tuning the affinity of the electrode-electrolyte interface. The specifically adsorbed Fe(II) ions [SA-Fe(II)] greatly alleviated the electrostatic repulsion around the interfaceresulting in a 10-fold lower in the adsorption-free energy of NO3- when compared to the case without SA-Fe(II). Meanwhile, the modulated interface accelerated the kinetic mass transfer process by 25 folds compared to the control. Under neutral conditions, a Faraday efficiency of 99.6%, a selectivity of 99%, and an extremely high NH3 yield rate of 485.8 mmol h-1 g-1 FeOOH were achieved. Theoretical calculations and in-situ Raman spectroscopy confirmed the electron-rich state of the SA-Fe(II) donated to p orbitals of N atom and favored the hydrogenation of *NO to *NOH for promoting the formation of high-selectivity ammonia. In sum, these findings complement the textbook on the specific adsorption of cations and provide insights into the design of low-cost NRA catalysts with efficient ammonia synthesis.

Pathophysiology of encapsulating peritoneal sclerosis: lessons from findings of the past three decades in Japan.

Encapsulating peritoneal sclerosis (EPS), a condition with a high mortality rate, is a serious complication of peritoneal dialysis (PD). In Japan, EPS became a central issue in the clinical setting during the mid-90s and the beginning of this century. However, following the introduction of biocompatible neutral PD solutions containing lower levels of glucose degradation products, the incidence and clinical severity of EPS has been greatly lessened. During the past three decades, the etiology of EPS has been elucidated by findings obtained by peritoneal biopsy, laparoscopy, and surgical intervention. Accumulating findings suggest the need for a paradigm change on the nature of EPS pathophysiology; notably, EPS appears not to reflect peritoneal sclerosis per se, but rather the formation of a neo-membrane as a biological reaction to peritoneal injury. This narrative review looks back on the history of EPS in Japan, and discusses EPS pathophysiology, the impact of neutral PD solution on peritoneal protection, and a future novel diagnostic approach, ultra-fine endoscope, for the identification of patients at high risk of EPS.

Effects of long-term treatment with low-GDP, pH-neutral solutions on peritoneal membranes in peritoneal dialysis patients.

BACKGROUND: The morphological changes induced by bio-incompatible peritoneal dialysis (PD) solutions are well known. However, the morphological damage induced by long-term low-glucose degradation product (GDP), pH-neutral solutions has not been reported in detail. The aim of this study was to investigate the long-term effects of pH-neutral PD solutions on morphological and functional changes in the peritoneal membrane. METHODS: We assessed peritoneal membrane biopsy samples from PD patients treated with acidic (Conventional group) or pH-neutral solutions (pH-neutral group) using pathology and immunopathology techniques. RESULTS: Analyses of 54 Conventional and 73 pH-neutral group samples showed that the peritoneal membrane was thicker (P < 0.001), the ratio of luminal diameter to vessel diameter (L/V ratio) was significantly smaller (P < 0.001), and advanced glycation end-product (AGE) accumulation was higher in the Conventional than in the pH-neutral group (P < 0.001). Comparison of samples from patients in the Conventional (n = 33) and pH-neutral groups (n = 33) who were treated for 4-10 years also showed significant differences in peritoneal thickness, L/V ratio and AGE score. Furthermore, the L/V ratio in the Conventional group significantly decreased over time (P < 0.01); however, no such change was seen in the pH-neutral group. Peritoneal membrane thickness was not associated with PD duration in both groups. Dialysate-to-plasma ratio of creatinine and L/V ratio negatively correlated with PD treatment duration in the Conventional group, but not in the pH-neutral group. CONCLUSIONS: These findings suggest that pH-neutral solutions prevent the morphological and functional peritoneal changes induced by long-term PD treatment.

Multidisciplinary clinical strategies for encapsulating peritoneal sclerosis in peritoneal dialysis: update from Japan.

Peritoneal dialysis is established as a first-line standard renal replacement therapy for end-stage renal disease. However, the development of encapsulating peritoneal sclerosis has been a critical complication among long-term peritoneal dialysis patients. During the past decade, multidisciplinary approaches have been used to suppress encapsulating peritoneal sclerosis. The present article reviews the historical and present status of encapsulating peritoneal sclerosis in Japan.

Survival of Bacteriophage T4 in Quasi-Pure Ionic Solutions.

The preservative qualities of individual ionic compounds impacting the infectivity of T4 virions were elucidated. T4 virions were immersed in quasi-pure ionic solutions prior to the adsorption process, and the plaque forming unit (pfu) values of these were measured following the conventional method. In neutral ionic solutions, the minimum and the optimum concentrations of preservative qualities corresponded with the results obtained from the multi-ionic media/buffers. In acid and alkali solutions, phages show tolerances at a pH range of 5-11 in multi-ionic media/buffers. T4 virions show no tolerance in quasi-pure acid, neutral, and weak alkaline conditions. The preservative quality of T4 virions increased in over 10-1 mM OH- solution, equivalent to a pH value over 10, which corresponds to the pKa of the deprotonation of the DNA bases G and T. Infectivity was lost below 10-1 mM OH- and higher than 10 mM OH-. These results imply that maintaining infectivity of a virion may need the flexibility of the intra-capsid DNA by deprotonation.

Non-Enzymatic Detection of Glucose in Neutral Solution Using PBS-Treated Electrodeposited Copper-Nickel Electrodes.

Transition metals have been explored extensively for non-enzymatic electrochemical detection of glucose. However, to enable glucose oxidation, the majority of reports require highly alkaline electrolytes which can be damaging to the sensors and hazardous to handle. In this work, we developed a non-enzymatic sensor for detection of glucose in near-neutral solution based on copper-nickel electrodes which are electrochemically modified in phosphate-buffered saline (PBS). Nickel and copper were deposited using chronopotentiometry, followed by a two-step annealing process in air (Step 1: at room temperature and Step 2: at 150 °C) and electrochemical stabilization in PBS. Morphology and chemical composition of the electrodes were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cyclic voltammetry was used to measure oxidation reaction of glucose in sodium sulfate (100 mM, pH 6.4). The PBS-Cu-Ni working electrodes enabled detection of glucose with a limit of detection (LOD) of 4.2 nM, a dynamic response from 5 nM to 20 mM, and sensitivity of 5.47 ± 0.45 µA cm-2/log10(mole.L-1) at an applied potential of 0.2 V. In addition to the ultralow LOD, the sensors are selective toward glucose in the presence of physiologically relevant concentrations of ascorbic acid and uric acid spiked in artificial saliva. The optimized PBS-Cu-Ni electrodes demonstrate better stability after seven days storage in ambient compared to the Cu-Ni electrodes without PBS treatment.

Encapsulating peritoneal sclerosis in the era of a multi-disciplinary approach based on biocompatible solutions: the NEXT-PD study.

INTRODUCTION: Encapsulating peritoneal sclerosis (EPS) is a serious complication of peritoneal dialysis (PD). Over the past decade in Japan, a multidisciplinary approach has been adopted to minimize the incidence and improve outcomes of EPS. This strategy includes planned PD discontinuation for high-risk patients and the introduction of biocompatible solutions. This study examined the current clinical status of EPS in representative PD centers in Japan. DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: Patients (n = 1,338) from 55 PD centers in Japan who were using neutral-pH solutions from the initiation of therapy (mean age, 62 years; median PD duration, 32 months; concomitant use of icodextrin, 35.2%; PD and hemodialysis combination therapy, 12.2%) were assessed every 6 months to ascertain the reasons for PD discontinuation and the development of EPS development. Outcomes were also recorded. The study period was from November 2008 to March 2012. RESULTS: There were 727 patients who discontinued PD, including 163 deaths. Among all causes of PD withdrawal except for death, planned PD discontinuation to avoid EPS was utilized in 58 cases (7.1% in total). The strategy was increasingly utilized in proportion to the duration of PD: 0.5% for patients undergoing PD for < 3 years, 0.6% for patients undergoing PD for 5 years, 14.7% for patients undergoing PD for 8 years, and 35.5% for patients undergoing PD for > 8 years. Fourteen patients developed EPS (three cases after PD), which corresponded with an overall incidence of 1.0%. The incidence according to the duration of PD was 0.3% for PD < 3 years, 0.6% for PD = 5 years, 2.3% for PD = 8 years, and 1.2% for PD > 8 years. In terms of therapy, 11 patients were treated with prednisolone (PSL), and surgical enterolysis was utilized in two cases. Complete remission of abdominal symptoms was achieved in twelve patients (85.7%), and three died due to EPS (mortality rate of 21.4%). CONCLUSIONS: Use of the multidisciplinary approach described above reduces the risk of the development of EPS according to PD duration. In cases of de novo EPS cases in Japan, this strategy can also attenuate the clinical course of the condition.