A Surface-Reconstructed Bilayer Heterojunction Enables Efficient and Stable Inverted Perovskite Solar Cells.

The efficiency of perovskite photovoltaics remains distant from their theoretical limits, primarily due to high photovoltage losses. Here a strategy is reported to minimize voltage losses by reconstructing the perovskite surface into a bilayer heterojunction (BLH) structure. Unlike conventional low-dimensional capping layers, typically constrained to a few nanometers to prevent low fill factors, this methodology facilitates a more comprehensive reaction with surface defects, allowing a more substantial capping layer (≈50 nanometers) without compromising charge transport integrity. Time-resolved microwave conductivity analysis indicates a significant reduction in trap density at the top region of the perovskite film, showing an order of magnitude lower than that of the pristine sample. Incorporating this BLH in inverted cells results in a remarkably low photovoltage deficit of 325 mV, leading to a power conversion efficiency (PCE) of 26.1% (25.72% certified). The encapsulated device maintains 94% of its original efficiency after 1200 h of maximum power point tracking under one sun illumination at 65 °C.

Impact of storage conditions on the shelf life of aflatoxin biocontrol products containing atoxigenic isolates of Aspergillus flavus as active ingredient applied in various countries in Africa.

Aflatoxin contamination significantly threatens food safety and security, particularly in tropical and sub-tropical regions where staple crops such as maize, groundnut, and sorghum become frequently affected. This contamination is primarily caused by the fungus Aspergillus flavus. The contamination causes adverse health effects, reduced income, and trade restrictions. In response to this challenge, various technologies have been developed to mitigate the impacts of aflatoxin. Among these, biocontrol products containing atoxigenic isolates of A. flavus as the active ingredient can effectively reduce aflatoxin levels both at pre- and post-harvest. A notable example of such products is Aflasafe, which contains four atoxigenic isolates native to specific target regions. These products have undergone rigorous testing, have received regulatory approval, and are commercially available in multiple African countries. However, their manufacturing processes have evolved, and comprehensive shelf life studies for current formulations are lacking. Evaluations of the spore production ability of atoxigenic A. flavus isolates in Aflasafe products over 4 years, under various storage conditions, revealed a significant linear decrease in sporulation with storage months (P < 0.001; R 2 = 0.203), with no significant differences observed between treatments. However, this marginal decline (P = 0.398) is unlikely to be sufficient to prevent the effectiveness in limiting aflatoxin. In addition, storing the products for 2 weeks at 54 °C did not affect (P > 0.05) the ability of the coated fungi to produce spores compared to when the products were stored at 24 °C. The findings contribute valuable insights for manufacturers and users of atoxigenic-based aflatoxin biocontrol products, informing best practices for product storage and utilization to ensure prolonged effectivenes in aflatoxin mitigation efforts.

Evaluation of Long-Term Stability in Single-Piece Implant Systems: An Original Research.

Background: Because of its integrated design and possible benefits over conventional two-piece systems, single-piece implant systems have grown in favor in the field of dental implantology. There is, however, still a dearth of information about their long-term stability and clinical results. The purpose of this study was to assess the clinical results, such as implant survival rates, peri-implant tissue health, and marginal bone levels, to determine the long-term stability of single-piece implant systems. Methods: About 127 individuals who got single-piece implants at the tertiary care center were the subject of a retrospective analysis. Standardized procedures were followed for implant implantation, and patients were monitored for at least five years afterward. Through radiographic analysis and clinical tests, clinical indicators such as marginal bone levels, peri-implant tissue health, and implant survival rates were evaluated. Results: With low marginal bone loss and good peri-implant tissue health, the research showed a high implant survival rate of 96.5%. A statistical study revealed significant relationships between marginal bone loss (P < 0.01), peri-implant tissue health (P < 0.05), and implant survival. Conclusion: In this study, single-piece implant devices showed good long-term durability and clinical results. These results confirm its effectiveness as a dependable dental rehabilitation alternative, highlighting the significance of preserving the health of the peri-implant tissue and reducing marginal bone loss to guarantee implant success.

The long-term transformation of FeIII-AsV coprecipitates at room temperature under oxic conditions: New insights for the fate and the speciation of As.

The long-term stability of FeIII-AsV coprecipitates, a typically hydrometallurgical or naturally produced As-bearing wastes in tailings or in other environments, is critical to evaluating the As risk caused by them. A wide pH range, different Fe/As molar ratios, reaction media, and neutralization reagents were considered in order to find the mechanisms controlling the fate of As during the 1640 days of transformation at 25 °C. The results indicated that at pH 4 and 12, As continuously released from the solid phase. The components and their proportions determined the fate of As at pH 4. However, at pH 12, crystalline calcium carbonates (CCA) formed due to the CO2 in the air and this combined with the adsorption capacity of As on the 2-line ferrihydrite controlling the fate of As. If pH changed to 8 and 10, yukonite formed after the release of As. The CCA also appeared in the presence of Ca. Therefore, these two processes controlled the fate of As at this pH range. These findings are important for understanding and predicting the transport of As under various environmental conditions. The technology chosen for As remediation in soils and As removal from waste waters will also be benefit from these results.

Long-term stability of a PTW 34070 large-area parallel ionization chamber in clinical proton scanning beams.

PURPOSE: In the modeling of beam data for proton therapy planning systems, absolute dose measurements are performed utilizing a Bragg peak chamber (BPC), which is a parallel-plate ionization chamber. The long-term stability of the BPC is crucial for ensuring accurate absolute dose measurement. The study aims to assess the long-term stability of the BPC in clinical proton pencil beam scanning delivery. METHODS: The long-term stability evaluation focused on the BPC-Type 34070 (PTW Freiburg, Germany), utilizing clinical proton scanning beams from December 2022 to November 2023. Monthly investigations were conducted to evaluate the response and cross-calibration factor of the BPC and a reference chamber, employing the spread-out Bragg peak (SOBP) field. Additionally, assessments were made regarding the BPC's response to monoenergetic beams, along with an examination of the impact of polarity and ion recombination on the BPC. RESULTS: The response and cross-calibration factor of the BPC varied up to 1.9% and 1.8%, respectively, while the response of the reference chamber remained within a 0.5% range. The BPC's response to the mono-energetic beams varied up to 2.0% across all energies, demonstrating similar variation trends in both the SOBP field and mono-energetic beams. Furthermore, the variations in polarity and ion recombination effect remained stable within a 0.4% range throughout the year. Notably, the reproducibility of the BPC remained high for each measurement conducted, whether for the SOBP field or mono-energetic beams, with a maximum deviation observed at 0.1%. CONCLUSIONS: The response and cross-calibration factor of the BPC demonstrated significant variations, with maximum changes of 1.9% and 1.8%, respectively. However, the reproducibility of the BPC remained consistently high for each measurement. It is recommended that when conducting absolute dose measurements using a BPC, its response should be compared and corrected against the reference chamber for each measurement.

Ampere-Level Hydrogen Generation via 1000 H Stable Seawater Electrolysis Catalyzed by Pt-Cluster-Loaded NiFeCo Phosphide.

Seawater electrolysis can generate carbon-neutral hydrogen but its efficiency is hindered by the low mass activity and poor stability of commercial catalysts at industrial current densities. Herein, Pt nanoclusters are loaded on nickel-iron-cobalt phosphide nanosheets, with the obtained Pt@NiFeCo-P electrocatalyst exhibiting excellent hydrogen evolution reaction (HER) activity and stability in alkaline seawater at ampere-level current densities. The catalyst delivers an ultralow HER overpotential of 19.7 mV at -10 mA cm-2 in seawater-simulating alkaline solutions, along with a Pt-mass activity 20.8 times higher than Pt/C under the same conditions, while dropping to 8.3 mV upon a five-fold NaCl concentrated natural seawater. Remarkably, Pt@NiFeCo-P offers stable operation for over 1000 h at 1 A cm-2 in an alkaline brine electrolyte, demonstrating its potential for efficient and long-term seawater electrolysis. X-ray photoelectron spectroscopy (XPS), in situ electrochemical impedance spectroscopy (EIS), and in situ Raman studies revealed fast electron and charge transfer from the NiFeCo-P substrate to Pt nanoclusters enabled by a strong metal-support interaction, which increased the coverage of H* and accelerated water dissociation on high valent Co sites. This study represents a significant advancement in the development of efficient and stable electrocatalysts with high mass activity for sustainable hydrogen generation from seawater.

Adult Herbst-multibracket appliance treatment-how stable are the results very long term?

AIM: To investigate the post-treatment (Tx) changes (≥ 15 years) in adult Class II patients treated with Herbst appliance and subsequently a multibracket appliance (MBA). SUBJECTS AND METHODS: Of 51 potential patients 31 could be located and participated (19 II:1 and 12 II:2). At a mean age of 21.8 ±â€…7.3 years (T0), Herbst-MBA Tx had been started. The mean post-Tx observation period was 19.8 ±â€…3.6 years. Study models from before and after Tx (T1, mean age: 23.6 ±â€…7.4 years), after 3.0 ±â€…2.8 years of retention (T2, mean age: 26.8 ±â€…8.3 years) as well as after recall (T3, mean age: 43.4 ±â€…7.5 years) were evaluated using the PAR index as well as standard occlusal variables. RESULTS: Pre-Tx, the mean values of the 31 participants were: PAR score = 26.1 ±â€…9.6 points, Class II molar relationship (MR) = 0.7 ±â€…0.2 cusp widths (CW), overjet = 6.9 ±â€…2.3 mm and overbite = 4.8 ±â€…2.6 mm. After Tx, the mean PAR score was 5.3 ±â€…2.8. A Class I MR (0.0 ±â€…0.1 CW) was present while overjet and overbite had decreased to 2.1 ±â€…0.7 and 1.3 ±â€…0.8 mm, respectively. At recall (19.8 ±â€…3.6 years post-Tx), a slight PAR score increase (+ 3.1 points) had occurred (final value: 8.4 ±â€…3.7); this was mainly due to mild increases in overjet, overbite (final values: 3.3 ±â€…1.4 mm and 2.5 ±â€…1.7 mm) and changes in sagittal MR (0.2 ±â€…0.2 CW). LIMITATIONS: The sample size and the participation rate as well as the unavailability of a comparable control group can be considered as limitations. In addition, no long-term radiographic data could be obtained, and the retention protocol was not uniform. The majority of these issues, however, should be acceptable to due to the duration of the observation period and the uniqueness of the data. CONCLUSION: In the present sample, Herbst-MBA Tx enabled Class II correction in adults with very good occlusal long-term stability.

Unraveling the Role of Electron-Withdrawing Molecules for Highly Efficient and Stable Perovskite Photovoltaic.

Electron-withdrawing molecules (EWMs) have exhibited remarkable efficacy in boosting the performance of perovskite solar cells (PSCs). However, the underneath mechanisms governing their positive attributes remain inadequately understood. Herein, we conducted a comprehensive study on EWMs by comparing 2,2'-(2,5-cyclohexadiene-1,4-diylidene) bismalononitrile (TCNQ) and (2,3,5,6-tetrafluoro-2,5-cyclohexadiene-1,4-diylidene) dimalononitrile (F4TCNQ) employed at the perovskite/hole transport layer (HTL) interfaces. Our findings reveal that EWMs simultaneously enhance chemical passivation, interface dipole effect, and chemically binding of the perovskite to the HTL. Notably, F4TCNQ, with its superior electron-withdrawing properties, demonstrates a more pronounced impact. Consequently, PCSs modified with F4TCNQ achieved an impressive power conversion efficiency (PCE) of 25.21%, while demonstrating excellent long-term stability. Moreover, the PCE of a larger-area perovskite module (14.0 cm2) based on F4TCNQ reached 21.41%. This work illuminates the multifaceted mechanisms of EWMs at the interfaces in PSCs, delivering pivotal insights that pave the way for the sophisticated design and strategic application of EWMs, thereby propelling the advancement of perovskite photovoltaic technology.

The recent advancement of outdoor performance of perovskite photovoltaic cells technology.

Perovskite solar cells achieved a record for power conversion efficiency of over 26 % for single junction cells and 34 % for planar silicon/perovskite tandems. These cells can be manufactured from low-cost materials with low-tech production techniques. As a result, it attracted great attention for future solar technology and multiple performance and stability studies have been reported in research articles. This work summarizes recent (2019-2023) reports on outdoor performance and stability tests of perovskite solar cells and modules in different locations and climate conditions. The review realized that there are limited works on outdoor testing of perovskite solar cells, and found only one year is the maximum long-term outdoor stability reported as at the time this review was conducted. The reports of this review demonstrated that accelerated aging tests of perovskite solar cells under harsh conditions such as elevated temperature, damp heat, and high relative humidity cannot replace realistic outdoor testing. As a result, studying the performance and stability of perovskite solar cells and modules under real outdoor conditions is very important to realize its commercialization.

Assessing the stability of responding of male mice in the touchscreen 5 choice serial reaction time task: Focus on premature responding.

The five-choice serial reaction time task (5CSRTT) is a test of attention that provides a well-validated ancillary measure of impulsive action, measured by premature responses. The task has been adapted for mice in touchscreen operant boxes, which is thought to offer improved test-retest reliability. Few studies have assessed the long-term stability of performance, including premature responding in this version of the task. We used the touchscreen 5CSRTT to conduct longitudinal testing of stability of premature responding following repeated behavioral and pharmacological manipulations. Male C57BL/6J mice were trained on a baseline version of the 5CSRTT. They were then tested on versions of the task in which the stimulus duration was reduced, and inter-trial intervals were elongated or varied within-session. Premature responding was subsequently tested following administration of pharmacological agents known to bi-directionally affect attention and impulsive action-cocaine, atomoxetine, and yohimbine. Mice were lastly re-tested 6 months later using the 5CSRTT with elongated inter-trial intervals. A reduced stimulus duration impacted attention, with reduced accuracy and increased omissions, but had no effect on premature responding. Both elongating and varying the inter-trial interval within-session increased premature responses. Mice showed similar and stable levels of increased premature responding 6 months later. Cocaine increased premature responding, though less than previously reported in rats. Atomoxetine reduced premature responding. Yohimbine had no effect on premature responding in the baseline task but decreased premature responding when tested using an elongated inter-trial interval. Overall, these results highlight that the touch screen adaptation of the 5CSRTT is an effective method for longitudinal testing of attention and impulsive action and remains sensitive to performance changes arising from repeated pharmacological and behavioral challenges.