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Abstract Sn-based perovskite solar cells (PSCs) have attracted attention because of their low environmental impact. Unfortunately, the readily occurring oxidation of Sn2+ inhibits further improvement of their efficiency and stability. Ruddlesden–Popper (RP) Sn-based perovskites are considered promising candidates as absorbers that improve the performance and stability of Sn-based PSCs. However, microscopic understanding of performance-enhancing mechanisms remains insufficient. For this study, electron spin resonance (ESR) spectroscopy measurements were taken of RP Sn-based PSCs with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transport layers and (BA0.5PEA0.5)2FA3Sn4I13 perovskite layers to clarify the space-charge region formation mechanism at the PEDOT:PSS/(BA0.5PEA0.5)2FA3Sn4I13 interface. These results indicated electron-barrier formation in the (BA0.5PEA0.5)2FA3Sn4I13 layer near the PEDOT:PSS layer. Moreover, the electron barrier was found to be enhanced during device operation. The enhanced interface band bending reduces interface recombination and thereby improves the device's performance. These findings might provide important progress in practical applications of PSCs and might advance the realization of a carbon-neutral society.

Minamata disease, a severe neurological disorder identified in Japan in 1956, results from methylmercury (MeHg) intoxication in humans due to environmental contamination. Before MeHg was recognized as the cause, selenium (Se) was suspected of being the potential cause owing to elevated Se levels in patients’ organs. Subsequent animal studies indicated that Se mitigates MeHg toxicity; however, its role in Minamata disease remains unexplored. We analyzed Hg and Se in historical samples of the industrial wastes (n = 4) on the factory site, sediments (n = 9), and fish/shellfish (n = 16) in Minamata Bay, and organs of patients with Minamata disease (n = 12). All samples showed elevated levels of both Hg and Se, providing the first evidence that Se was also discharged into Minamata Bay, entering the food chain and accumulating at high levels in patient organs. The Hg/Se molar ratio in contaminated shellfish (median > 3.0) indicated exceptionally high MeHg exposure, far exceeding the ordinary level (< 1.0). Patients exhibited significantly increased Se levels in the liver and kidney but lower amounts in the brain. Notably, median Hg/Se molar ratios exceeding 4.0 were observed, particularly in the cerebrum and cerebellum in acute cases, closely mirroring the molar ratios found in seafood. The elevated Hg/Se molar ratio in the brain helps explain the severe neurological damage in patients’ central nervous systems, despite higher Hg levels in the liver and kidney compared to the brain. These findings provide important insight into the mechanism of MeHg intoxication and highlight the risks associated with MeHg-contaminated seafood, aiding efforts to protect consumers.

Abstract Light-emitting electrochemical cells (LECs) are next-generation devices that are flexible, emit light and have several advantages over organic light-emitting diodes, such as a simpler structure and lower cost. However, the operation mechanism of LECs remains unknown from a microscopic viewpoint. Here, we perform an operando microscopic investigation of LECs with Super Yellow, a typical light-emitting material, by observing the spin states of electrically doped charges using electron spin resonance. The operando electron spin resonance and light emission increase as the voltage applied to the LECs increases. Through density functional theory, we determine that the origin of the electron spin resonance increases to be from electrochemically doped holes and electrons in Super Yellow. We find that the doping progress correlates with the luminance increase, suggesting that electrochemically doped charges are distributed over the light-emitting layer as the operation mechanism. Moreover, we deduce the molecular orientation of electrochemically charge-doped Super Yellow.

BackgroundAltered immunological responses in the palatine tonsils may be involved in the pathogenesis of IgA nephropathy (IgAN). The germinal center serves as the site for antigen-specific humoral immune responses in the palatine tonsils. Germinal center involution is frequently observed in the palatine tonsils of IgAN (IgAN tonsils). However, the pathogenic significance of these characteristic changes remains unclear. This study aimed to investigate the morphological changes in secondary lymphoid follicles in IgAN tonsils and to evaluate the correlation between the morphometric results and the clinicopathological severity of IgAN.MethodsThe tonsils of age-matched patients with recurrent tonsillitis (RT tonsils) were used as controls. The correlation between the degree of lymphoid follicular involution and histopathological severities in clinical or kidney biopsy was evaluated.ResultsIn total, 87 patients with IgAN were included (48% male, median age 35 years, median estimated glomerular filtration rate: 74 mL/min/1.73 m2). Compared to RT tonsils, IgAN tonsils showed smaller median sizes of lymphoid follicles and germinal centers (P < 0.001). The relative areas of lymphoid follicles (%LFA) and germinal centers (%GCA) in the total tonsillar tissue were smaller in the IgAN tonsils than in the RT tonsils (P < 0.001). In contrast, the median proportion of mantle zones in the total tonsillar tissue was comparable between the groups. A lower %LFA was associated with a longer period from the onset of urinary abnormalities to biopsy diagnosis and higher urinary protein excretion (P = 0.01). %LFA showed significant negative correlations with frequencies of glomeruli with both global and segmental sclerosis.ConclusionsThe present study confirmed accelerated germinal center involution in the tonsils of patients with IgAN. This characteristic change in the IgAN tonsil correlates with heavy proteinuria and advanced chronic histopathological changes in the kidneys, thereby suggesting the involvement of repeated tonsillar immunoreactions during IgAN progression.

This study presents a new gas metal arc welding (GMAW) technique that achieves both high efficiency and low heat input using a hybridization of the hot-wire method. The optimal combination of welding speed and welding current conditions was investigated using a fixed hot-wire feeding speed of 10 m/min on a butt joint with a V-shaped groove using 19 mm thick steel plates. Molten pool stability and defect formation were observed using high-speed imaging and cross-sectional observations. The power consumption and heat input were predicted prior to welding and measured in the experiments. The results indicate that a combination of a welding current of 350–500 A and welding speed of 0.3–0.7 m/min is optimal to avoid defect formation and molten metal precedence using three or four passes. The higher efficiency and lower heat input achieved by hot-wire GMAW results in a weld metal of adequate hardness, narrower heat-affected zone, smaller grain size at the fusion boundary, and lower power consumption than those obtained using tandem GMAW and high-current GMAW. Based on the experimental results, a single bevel groove, which is widely used in construction machinery welding joints, was welded using hot-wire GMAW, and we confirmed that the welding part could be welded in six passes, whereas eight passes were required with GMAW only.

The formation of brittle intermetallic compounds (IMCs) at the interface between dissimilar materials causes considerable problems. In this study, a multi-material additive manufacturing technique that employs a diode laser and the hot-wire method was developed for stainless steel/aluminum alloys. An Al-Mg aluminum alloy filler wire (JIS 5183-WY) was fed on an austenitic stainless-steel plate (JIS SUS304) while varying the laser power and process speed and using paste-type flux and flux-cored wire. The effects of laser power and process speed on phenomena during manufacturing and IMC formation were investigated. Finally, the wall-type multilayer specimens were fabricated under optimized conditions. The suppression of IMC formation to a thickness of less than 2 μm was achieved in the specimens, along with a high interfacial strength of over 120 MPa on average.

Organic photovoltaic devices (OPVs) are attracting attention because of recent rapid enhancement of their power conversion efficiency. For further improvement, optimization of fabrication processes is one useful path to a solution. During OPV fabrication, particularly of the bulk heterojunction active layer, annealing treatments contribute to the device performance. Many studies have examined annealing-related properties. However, further research must clarify how paramagnetic species in the devices play their roles by annealing. Using well-known OPVs, we investigated the relation between spin-dependent recombination (SDR) current and the paramagnetic species, which vary the numbers by post-annealing with active layers consisting of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM). A simultaneous detection method of electron spin resonance (ESR) and electrically detected magnetic resonance (EDMR), which we originally developed, was applied to OPVs for the first time ever reported. Results show that PC 61 BM anion radicals generated by post-annealing of P3HT:PC 61 BM OPVs with a lithium fluoride (LiF)/aluminum (Al) electrode do not contribute to the SDR current at the interface and that P3HT cation radicals enhance the SDR current. By contrast, devices with an Al electrode without LiF decrease the total SDR current, although the quantities of cation radical molecules do not vary. This finding suggests that changes of the hole blocking layer in the devices caused by the annealing treatment affect the size of capture cross sections of P3HT cation radicals. Our new method of quantitative observation of the EDMR changes through the ESR signals is expected to be useful for investigating the capture cross sections in OPVs. [ABSTRACT FROM AUTHOR]

Abstract This study investigated how the SiNx refractive index (RI) and SiO2 thickness, dox, of stacked SiNx/SiO2 passivation layers of the front p+emitters of n‐type crystalline‐silicon (c‐Si) photovoltaic (PV) cells affect their polarization‐type potential‐induced degradation (PID) behaviors. We prepared six n‐type c‐Si PV cells with an RI of 2.0 or 2.2 and with dox of 9, 2, or 1 nm. Then PV modules fabricated from the cells were subjected to PID tests during which a bias of −1000 V was applied to cells with respect to the front cover glass surface. For dox of 9 or 2 nm, rapid polarization‐type PID was observed, irrespective of the RI. However, for dox of 1 nm, the RI markedly affected the degradation behavior, and cells with an RI of 2.2 showed no degradation. These findings are attributable to carrier transport between the high RI (Si‐rich) SiNx and the c‐Si substrates, which can readily occur only when the SiO2 layer is sufficiently thin for electrons to tunnel through the SiO2 layer. These results are important for elucidating polarization‐type PID mechanisms and for developing preventive measures against polarization‐type PID.

Application of high-heat input welding on high-tensile strength steels causes deterioration of mechanical properties of the welded joint, due to softening and grain coarsening in the heat-affected zone (HAZ). In this study, low-heat input narrow-gap hot-wire laser welding was applied to 12 mm thick 780 MPa-class high-tensile strength steel plate. Conditions were optimized based on microstructural observations of joints produced at various welding speeds. Heat input was estimated from measured grain size. Evaluation of properties of joints welded at 0.5 m/min revealed sound toughness, tensile strength, and elongation. The effect of undermatched weld metal width on joint strength was analyzed using a finite element method. When the width of undermatched weld metal was 2.5 mm, the joint strength was 99% of the base metal strength; when it was 7.5 mm, the strength dropped to 95%. The effect of HAZ softening width on joint strength with even-matched weld metals was similarly analyzed, showing that even when the HAZ softening width was 2.0 mm, the joint strength was 98% of the base metal strength. The results of this study suggest that narrow-gap hot-wire laser welding can efficiently reduce heat input and the HAZ softening zone, thereby achieving both high strength and high toughness. [ABSTRACT FROM AUTHOR]

Sn-based perovskite solar cells (PSCs) have attracted attention because of their low environmental impact. Unfortunately, the readily occurring oxidation of Sn2+ inhibits further improvement of their efficiency and stability. Ruddlesden–Popper (RP) Sn-based perovskites are considered promising candidates as absorbers that improve the performance and stability of Sn-based PSCs. However, microscopic understanding of performance-enhancing mechanisms remains insufficient. For this study, electron spin resonance (ESR) spectroscopy measurements were taken of RP Sn-based PSCs with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transport layers and (BA0.5PEA0.5)2FA3Sn4I13 perovskite layers to clarify the space-charge region formation mechanism at the PEDOT:PSS/(BA0.5PEA0.5)2FA3Sn4I13 interface. These results indicated electron-barrier formation in the (BA0.5PEA0.5)2FA3Sn4I13 layer near the PEDOT:PSS layer. Moreover, the electron barrier was found to be enhanced during device operation. The enhanced interface band bending reduces interface recombination and thereby improves the device's performance. These findings might provide important progress in practical applications of PSCs and might advance the realization of a carbon-neutral society. [ABSTRACT FROM AUTHOR]

Using a successive detection technique with electron spin resonance (ESR) and electrically detected magnetic resonance (EDMR), this study clarifies the quantitative correlation between photoinduced spin amounts and spin-dependent recombination (SDR) currents in organic photovoltaic devices (OPVs). Using this unique method of sequentially switching between ESR and EDMR measurements under light irradiation, we find that the intensities of light-induced ESR and EDMR spectra increase along with the light irradiation power. Although positive correlation exists between the number of photo-generated radicals and the SDR currents, the relation is not proportional, which demonstrates that most of the photo-generated radicals are residual accumulated charges. Additionally, phases of the EDMR spectra under light irradiation were found to be changed because of a delay of modulated EDMR signals. The phase variation is probably caused by recombination centers: positive polarons that have arrived at the interface between an aluminum electrode and an active layer by charge drifting after charge separation. Because positive polarons are expected to transport positive charges to the opposite-side electrode of the aluminum as a negative charge collector, this leakage current can be a factor of disturbing an optimal charge collection. This combined technique of ESR and EDMR is useful to explore the different roles of polarons in the photovoltaic conversion processes, thereby providing important information for improving the fill factors and open-circuit voltages of the OPVs, which generate long-lived polarons. [ABSTRACT FROM AUTHOR]

Background Aortoesophageal fistula (AEF) is a life-threatening disease that causes massive bleeding, sepsis, and ultimately death. Therefore, emergency treatments are required. Recently, cases of AEF treated with thoracic endovascular aortic repair (TEVAR) have been reported. Case summary An 84-year-old man was referred to a local hospital with massive haematemesis and transient loss of consciousness. The patient's medical history included radiotherapy for oesophageal cancer 19 years before presentation. Gastrofiberscopy revealed an ulcer in the thoracic oesophagus and no recurrence of oesophageal cancer. Computed tomography (CT) showed that the same area was adjacent to the thoracic aorta and that there was no thoracic aortic aneurysm. The patient was then transferred to our institution for surgical treatment. We diagnosed the patient with an AEF caused by radiotherapy of the oesophagus. Therefore, TEVAR was performed. Due to the patient's advanced age, condition, and the possibility of strong adhesions, there was a high risk that they would be unable to tolerate oesophagectomy to prevent stent graft infection. Therefore, antibiotic therapy was initiated. However, CT revealed a stent graft infection 24 days after TEVAR. The patient died of sepsis 27 days after the procedure. Discussion We describe the first case of AEF as a very late complication of radiotherapy for oesophageal cancer. Surgery to repair oesophageal defects is necessary to prevent stent graft infection. However, the decision for such surgery should be made on a case-by-case basis, taking into account the patient's condition and ability to tolerate the procedure. [ABSTRACT FROM AUTHOR]

Abstract Ternary polymer solar cells based on a thiazolothiazole-based polymer donor (PTzBT) and a fullerene acceptor (PC61BM) have attracted attention because they show high efficiency and stability by addition of a non-fullerene acceptor (ITIC). However, the performance improvement mechanism is not completely elucidated. Here, we show the stability improvement mechanism due to less charge accumulation in the PTzBT cells with ITIC using operando electron spin resonance from a microscopic viewpoint. We observed two correlations between device performance and number of spins (N spin) under solar irradiation. One correlation is the decrease in short-circuit current and the N spin increase in electrons on PC61BM and holes in PTzBT, where the ITIC addition causes the less these N spin. The other correlation is the increase in open-circuit voltage and the N spin decrease in holes in ZnO. These findings explain the stability improvement mechanism, showing the correlation between less charge accumulation and higher stability, which is valuable for the development of further efficient and stable polymer solar cells.

Potential‐induced degradation (PID) has been identified as a central reliability issue of photovoltaic (PV) cell modules. Several types of PID depend on the cell structure. Among those types, polarization‐type PID, which is characterized by reductions in short‐circuit current density (JSC) and open‐circuit voltage (VOC), is the fastest PID mode. Additionally, polarization‐type PID occurs readily at room temperature or at markedly low magnitudes of electric potential difference. Therefore, polarization‐type PID is a severe difficulty affecting silicon PV modules. Recently, degradation behavior, preventive measures, and mechanism have been investigated. As described herein, mechanistic aspects of polarization‐type PID are specifically examined and details of a recently proposed model involving a charge accumulation process at K centers in SiNx dielectric layers: the K‐center model are discussed. The K‐center model consistently explains previously reported results of experimentation, which indicates the validity of this model. Discussions presented herein are expected to improve the mechanistic understanding of polarization‐type PID in the PV community and to stimulate further discussions and verifications of the model.

The establishment of the surviving arbuscular mycorrhizal (AM) fungi, Gigaspora margarita Becker & Hall, inoculated in revegetation at the Nukui Dam was studied. The population of AM fungi and AM colonization of three plant species Japanese hill cherry (Prunus jamasakura Sieb. ex Koidz, yamazakura-inoculated plant), eulalia (Miscanthus sinensis Anderss, susuki), and mugwort (Artemisia vulgaris Pampan, yomogi) were investigated to compare inoculated and non-inoculated treatments. The AM colonisation was enhanced in inoculated plots although natural or accidental AM fungi were involved in non-inoculated plots and successfully colonised. Coverage of soil surface was more than 80% and even reached nearly 100% in summer regardless of the soil amendment type. The number of spores and the percentage of colonisation of investigated plant roots, as well as the density of typical AM structures such as arbuscules, auxiliary cells, vesicles, and coiling hyphae by AM fungi in inoculated plots were higher than those in non-inoculated ones. Some spores were Gigaspora and Glomus-inoculated species and were relatively rich in inoculated plots of Yamazakura. There was a significant increase in the number of AM spores in inoculated treatments at a 5% confidence level (ANOVA, p