A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements.

The electrochemical synthesis of ammonia from nitrogen under mild conditions using renewable electricity is an attractive alternative1-4 to the energy-intensive Haber-Bosch process, which dominates industrial ammonia production. However, there are considerable scientific and technical challenges5,6 facing the electrochemical alternative, and most experimental studies reported so far have achieved only low selectivities and conversions. The amount of ammonia produced is usually so small that it cannot be firmly attributed to electrochemical nitrogen fixation7-9 rather than contamination from ammonia that is either present in air, human breath or ion-conducting membranes9, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream10, in the atmosphere or even in the catalyst itself. Although these sources of experimental artefacts are beginning to be recognized and managed11,12, concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments designed to identify and then eliminate or quantify the sources of contamination. Here we propose a rigorous procedure using 15N2 that enables us to reliably detect and quantify the electrochemical reduction of nitrogen to ammonia. We demonstrate experimentally the importance of various sources of contamination, and show how to remove labile nitrogen-containing compounds from the nitrogen gas as well as how to perform quantitative isotope measurements with cycling of 15N2 gas to reduce both contamination and the cost of isotope measurements. Following this protocol, we find that no ammonia is produced when using the most promising pure-metal catalysts for this reaction in aqueous media, and we successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13. The use of this rigorous protocol should help to prevent false positives from appearing in the literature, thus enabling the field to focus on viable pathways towards the practical electrochemical reduction of nitrogen to ammonia.

Author Correction: A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Exsolution of Ru Nanoparticles on BaCe0.9 Y0.1 O3-δ Modifying Geometry and Electronic Structure of Ru for Ammonia Synthesis Reaction Under Mild Conditions.

Green ammonia is an efficient, carbon-free energy carrier and storage medium. The ammonia synthesis using green hydrogen requires an active catalyst that operates under mild conditions. The catalytic activity can be promoted by controlling the geometry and electronic structure of the active species. An exsolution process is implemented to improve catalytic activity by modulating the geometry and electronic structure of Ru. Ru nanoparticles exsolved on a BaCe0.9 Y0.1 O3-δ support exhibit uniform size distribution, 5.03 ± 0.91 nm, and exhibited one of the highest activities, 387.31 mmolNH3  gRu -1  h-1 (0.1 MPa and 450 °C). The role of the exsolution and BaCe0.9 Y0.1 O3-δ support is studied by comparing the catalyst with control samples and in-depth characterizations. The optimal nanoparticle size is maintained during the reaction, as the Ru nanoparticles prepared by exsolution are well-anchored to the support with in-plane epitaxy. The electronic structure of Ru is modified by unexpected in situ Ba promoter accumulation around the base of the Ru nanoparticles.

Clinical history of female-to-male transgender patients is needed to avoid misinterpretation of cervical Papanicolaou tests.

OBJECTIVE: Cervical cancer screening is as important in female-to-male transgender (FTMT) patients as it is in cisgender female patients. The aim of this study was to examine the impact of clinical information regarding gender identity and testosterone therapy on the cytological interpretations. METHODS: A list of FTMT patients and cisgender female patients who had received a cervical Papanicolaou (Pap) test for cancer screening was obtained. The cytological diagnoses, rendered at the time of collection, were recorded. A retrospective slide review with knowledge of the pertinent clinical information, including testosterone therapy status, was performed. The data sets were statistically compared. RESULTS: Of 122 cervical Pap tests in 111 FTMT individuals, 23 (19%) had surgical follow-ups; 73 (60%) had HPV testing, of which 12 (16%) were positive for high-risk strains; and 79 (65%) were known to be receiving testosterone. On the "original" review, 12 (9.8%) tests were diagnosed as unsatisfactory. Seventy-one (58%) Pap tests were initially diagnosed as negative for intraepithelial lesion or malignancy (NILM) without atrophy and 32 (26%) with atrophy. Seven (5.7%) of the tests were initially diagnosed as abnormal. On the "retrospective" review, the rate of unsatisfactory tests remained the same, and atrophy was observed in 76 (62%) tests. The number of abnormal tests was reduced to 4 (3.3%) after the retrospective review. Almost all comparative studies returned a P-value of ≤0.05. CONCLUSION: Our findings indicate that clinical information regarding whether a subject is transgender and/or is receiving testosterone therapy is crucial to avoiding Pap test overcalls.

Accelerating problem-solving capacities of sub-national public health professionals: an evaluation of a digital immunization training intervention.

BACKGROUND: This article reports an evaluation of the Immunization Training Challenge Hackathons (ITCH), invented by The Geneva Learning Foundation (TGLF) for national and sub-national immunization staff who strive to develop the knowledge and capacity of others to improve immunization program performance. ITCH, a fully-digital program focused on networked collaborative problem-solving between peers, provided an "opt-in" activity for learners in the Teach to Reach (T2R) Accelerator Program designed to improve training effectiveness in the immunization sphere. METHODS: Conducted by a team from the University of Georgia, this mixed method evaluation consisted of thematic analysis of recorded sessions and open-ended comments; and statistical analyses of application and follow-up survey data. The evaluation focused on what was learned and how ITCH participants implemented what they learned. Key stakeholder interviews provided supplemental data about program intent and results. ITCH consisted of 17 30-min sessions held in 2020, in English and French, with 581 participating at least once out of 1,454 enrolled in the overall program. Challenge owners and respondents came from 15 African and Asian countries and spanned different roles with differing scope. RESULTS: Over 85% [n = 154] of survey respondents [n = 181, a 31% response rate] indicated they were able to implement what they learned from the ITCH sessions. A majority [n = 139, 76.7%] reported finding the sessions useful. Issues with poor connectivity and the timing of the live meetings impeded some in their ability to participate, a problem compounded by consequences of the pandemic. The ITCH process constituted of learning or coming to consciousness simultaneously of four types of learning - participants realizing how much they could learn from each other (peer learning), experiencing the power of defying distance to solve problems together (remote learning), and feeling a growing sense of belonging to a community (social learning), emergent across country borders and health system levels (networked learning). CONCLUSIONS: Based on evaluation findings, it was concluded that ITCH demonstrated an effective scalable, informal, non-didactic, experience-led, fast-paced, peer learning design. A focus on community engagement and developing brokering skills was recommended.

Comparison of Anti-Bacterial Efficacy between Passive Ultrasonic Irrigation and 980 nm-GaAlAs Laser Application in Two Root Types.

Background and Objectives: The purpose of the present study was to investigate the anti-bacterial efficacy of passive ultrasonic irrigation (PUI) and a 980-nm-gallium-aluminum-arsenide (GaAlAs) laser using a real-time DNA-based quantitative polymerase chain reaction (qPCR) assay and scanning electron microscopy (SEM). Materials and Methods: Eighty-six extracted single- and double-rooted human teeth were used in the experiment. The following four experimental groups were evaluated, as well as a control group: group 1: single root + PUI (n = 20); group 2: single root + laser application (n = 20); group 3: double roots + PUI (n = 20); group 4: double roots + laser application (n =20); control group (n = 6): 3 single roots, 3 double roots. The qPCR assay was performed in three stages to evaluate the efficacy of the adjunctive method against Enterococcus faecalis. SEM analysis was also used to examine the microstructure of root canal surfaces. The data were statistically analyzed using the Friedman test and the Kruskal-Wallis test with Bonferroni adjustment. Results: The decrease in the DNA levels from S1 (before preparation) to S2 (just after preparation) was highly significant in all groups, and decreases in DNA levels from S2 to S3 (after incubation for 1 week) were found in all experimental groups except group 1. An inter-group analysis showed that PUI was significantly more effective in terms of antibacterial efficacy than GaAlAs laser irradiation in single root (p < 0.05). However, in double roots, experimental groups did not show significantly lower DNA levels than the control group (p > 0.05). SEM images showed that cleaning of the root canal surface and reduction of dentin debris were achieved only in single-rooted teeth when using PUI application. Conclusions: Two adjunctive methods were effective in reducing E. faecalis in single rooted tooth.

Influence of Luting Materials and Methods and the Restoration Surface on the Amount of Cement Remnants in Implant Restorations.

This study aimed to investigate the effects of the luting methods on the amount of cement remnants in implant restorations and to determine the restoration surface with the maximum amount of residual cement. Forty abutments and crowns were divided into 4 groups as follows: TB group, luting with zinc oxide-eugenol cement; TBV group, luting with zinc oxide-eugenol cement after application of a separating agent over the transmucosal area of the abutment; PI group, luting with methacrylate cement; and PIV group, luting with methacrylate cement after application of a separating agent. After cementation, all the quadrants of the specimens were photographed, and the amount and location of the cement remnants were statistically analyzed (P ≤ .05). The amount of cement remnants was significantly smaller in the groups with a separating agent. The type of luting material did not significantly affect the results. Cement remnants were more abundant on the mesial and distal sides than on the buccal and lingual sides of the restoration.

Analysis of the characteristics of cracked teeth and evaluation of pulp status according to periodontal probing depth.

BACKGROUND: The purpose of this study was to analyze the characteristics of cracked teeth and to evaluate pulp status according to periodontal probing depth (PPD). METHODS: A total of 182 cracked teeth were included. The location and type of the cracked teeth, age and gender of the patients, restoration type, pulp status, PPD, and radiographic findings were analyzed. RESULTS: Mandibular second molars (25.3%) were the most frequently involved teeth, followed by mandibular first molars (22.5%), maxillary first molars (22.0%), and maxillary second molars (17.6%). The patient age was most frequently 50-59 years. Cracks occurred mainly in nonbonded restorations, such as gold (26.9%), and were usually found in intact teeth (37.9%). A total of 103 teeth (56.6%) had an initial PPD of less than 3 mm, while 40 (22.0%) had a PPD of 4-6 mm, and 39 (21.4%) had PPD of 7 mm or more. A total of 33 cracked teeth (18.1%) were diagnosed with pulp necrosis, 40 (22.0%) with irreversible pulpitis, and 97 (53.3%) with reversible pulpitis. The incidence of pulp necrosis was 31.8% among cracked teeth with a PPD of 4-6 mm, and 28.6% among those with a PPD of 7 mm or more. CONCLUSIONS: Cracks occurred mainly in molar teeth, and were commonly found in intact teeth with no restoration. Patients with cracked teeth were most frequently aged 50-59 years. Cracked teeth showing a PPD of more than 4 mm were more likely to show pulp necrosis.

A Sociocultural Approach to Children's Perceptions of Death and Loss.

By employing the phenomenographic approach, the present study explored children's cognitive understanding of and emotional responses to death and bereavement. Participants included 52 Korean, 16 Chinese, and 16 Chinese American children ages 5-6. Thematic analysis of children's drawings and open-ended interviews revealed that most children associated death with negative emotions such as fear, anxiety, and sadness. The majority of children used realistic expressions to narrate death. The core themes from their drawings included causes for death, attempts to stop the dying, and situations after death. This study contributes to the literature by targeting young children who have been relatively excluded in death studies and provides evidence in the usefulness of drawings as a developmentally appropriate data collection tool. The findings also enrich our knowledge about children's understanding of death and bereavement, rooted in the inductive analysis of empirical data with children from culturally diverse backgrounds.