skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Fusing perylene diimide with helicenes
Abstract Incorporating perylene diimide (PDI) units into helicene structures has become a useful strategy for giving access to non‐planar electron acceptors as well as a method of creating molecules with unique and intriguing chiroptical properties. This minireview describes this fusion of PDIs with helicenes.  more » « less
Award ID(s):
2002634
PAR ID:
10419349
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Chirality
ISSN:
0899-0042
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Background and objectivesThe coproduct of ethanol industry, dried distiller's grains with solubles (DDGS), has phosphorus content in excess of the animal diet requirement, which leads to excess P in manure and causes environmental concerns. The objective of this study is to determine the technical and economic feasibility of recovering this excess P as a coproduct. FindingsThe amount of P was observed to reduce from 9.26 to 3.25 mg/g (db) of DDGS, which is consistent with the animal diet requirement of 3–4 mg P/g animal diet. For an existing dry grind plant of 40 million gallon ethanol capacity, an additional fixed cost of $5.7 million was estimated, with an operating cost increase of $1.29 million/year. ConclusionsThe total phosphorus recovered from the plant was estimated as 1,676 kg P/day, with an estimated operating cost of $2.33/kg P recovered. Significance and noveltyApproximately 37 million MT of DDGS is produced annually as animal food containing excess P, which is a serious concern for the environment. This study provides with an economically feasible solution to recover the excess P as a coproduct, which has a potential to be used as fertilizer on more than 56,000 acres of land annually, growing corn and soybean. 
    more » « less
  2. Abstract BackgroundResearch points to family talk and interactions involving STEM concepts as one of the most influential informal learning experiences that shape an individual's STEM identity development and encourage their pursuit of a STEM career. However, a recent literature review uncovers limited research regarding the development of engineering identity in young children. PurposeThe purpose of this study was to add to this scant literature by exploring how children position themselves as engineers and how children are positioned as engineers through interactions with parents and other adults within a program focused on family engagement within an engineering design process. MethodsThis study includes two parent–child dyads. We collected and analyzed approximately 19.5 h of video data of the two child–parent dyads interacting with one another throughout an engineering design process as part of an out‐of‐school program. ResultsResults highlight three ways in which the two children enacted various engineering identities through their positioning, negotiation, and acceptance and/or rejection of positionalities as they engaged in an engineering design process with a parent. These identity enactments included (a) possessing knowledge and authority to make decisions regarding the development of their self‐identified engineering problem and prototype; (b) questioning and challenging adult ideas, solutions, and construction of prototypes; and (c) documenting and communicating their thinking regarding the engineering design through sketches and notes. ConclusionsThe significance of this study lies in its potential to change the landscape of those who pursue an engineering career and to contribute to the limited research and ongoing conversations about how to foster environments that support families in creative and collaborative learning specific to the engineering discipline. 
    more » « less
  3. Abstract BackgroundWhile most health-care providers now use electronic health records (EHRs) to document clinical care, many still treat them as digital versions of paper records. As a result, documentation often remains unstructured, with free-text entries in progress notes. This limits the potential for secondary use and analysis, as machine-learning and data analysis algorithms are more effective with structured data. ObjectiveThis study aims to use advanced artificial intelligence (AI) and natural language processing (NLP) techniques to improve diagnostic information extraction from clinical notes in a periodontal use case. By automating this process, the study seeks to reduce missing data in dental records and minimize the need for extensive manual annotation, a long-standing barrier to widespread NLP deployment in dental data extraction. Materials and MethodsThis research utilizes large language models (LLMs), specifically Generative Pretrained Transformer 4, to generate synthetic medical notes for fine-tuning a RoBERTa model. This model was trained to better interpret and process dental language, with particular attention to periodontal diagnoses. Model performance was evaluated by manually reviewing 360 clinical notes randomly selected from each of the participating site’s dataset. ResultsThe results demonstrated high accuracy of periodontal diagnosis data extraction, with the sites 1 and 2 achieving a weighted average score of 0.97-0.98. This performance held for all dimensions of periodontal diagnosis in terms of stage, grade, and extent. DiscussionSynthetic data effectively reduced manual annotation needs while preserving model quality. Generalizability across institutions suggests viability for broader adoption, though future work is needed to improve contextual understanding. ConclusionThe study highlights the potential transformative impact of AI and NLP on health-care research. Most clinical documentation (40%-80%) is free text. Scaling our method could enhance clinical data reuse. 
    more » « less
  4. Abstract AimThe geography and genesis of diversity remain an enduring topic in ecology and evolution. Mediterranean Climate Ecosystems (MCEs), with their high plant diversities in winter rainfall climates, pose a challenge to popular hypotheses evoking high water availability and temperature as necessary for the evolution of high diversity. We test the hypothesis of environmental stability as a driver for the evolution of regional‐scale floristic diversity using speleothem oxygen (δ18O) and carbon (δ13C) isotopic values as proxies for past climatic variability in the Cape Floristic Region (CFR) and other MCEs. Locationsouth‐western Africa, California, Mediterranean Basin. TaxonPlantae. MethodsWe present new speleothem δ18O and δ13C records from a cave near Robertson in the western CFR. Stable isotope samples included in the analyses cover the time intervals between 240 and 670 ka BP with hiatuses at 630–500 ka and 360–310 ka. The dispersion of these stable isotope records is used as a measure for climatic variability. We compare our new analyses to speleothem records that cover full glacial and interglacial conditions in other MCEs (California and the Mediterranean Basin) as well as in eastern regions of the CFR. All sites used in this comparison have lower vascular plant biodiversity than the western CFR. ResultsAnalyses of the dispersion of the δ18O and δ13C datasets suggest that the highly diverse western CFR experienced climatic stability across several glacial–interglacial cycles, compared with the less diverse regions within and outside of the CFR. Main ConclusionThis result provides support for the hypothesis that lower extinction rates associated with Pleistocene biome stability may explain the higher diversity in the CFR relative to other MCEs. 
    more » « less
  5. ImportanceEfforts to understand the complex association between social media use and mental health have focused on depression, with little investigation of other forms of negative affect, such as irritability and anxiety. ObjectiveTo characterize the association between self-reported use of individual social media platforms and irritability among US adults. Design, Setting, and ParticipantsThis survey study analyzed data from 2 waves of the COVID States Project, a nonprobability web-based survey conducted between November 2, 2023, and January 8, 2024, and applied multiple linear regression models to estimate associations with irritability. Survey respondents were aged 18 years and older. ExposureSelf-reported social media use. Main Outcomes and MeasuresThe primary outcome was score on the Brief Irritability Test (range, 5-30), with higher scores indicating greater irritability. ResultsAcross the 2 survey waves, there were 42 597 unique participants, with mean (SD) age 46.0 (17.0) years; 24 919 (58.5%) identified as women, 17 222 (40.4%) as men, and 456 (1.1%) as nonbinary. In the full sample, 1216 (2.9%) identified as Asian American, 5939 (13.9%) as Black, 5322 (12.5%) as Hispanic, 624 (1.5%) as Native American, 515 (1.2%) as Pacific Islander, 28 354 (66.6%) as White, and 627 (1.5%) as other (ie, selecting the other option prompted the opportunity to provide a free-text self-description). In total, 33 325 (78.2%) of the survey respondents reported daily use of at least 1 social media platform, including 6037 (14.2%) using once a day, 16 678 (39.2%) using multiple times a day, and 10 610 (24.9%) using most of the day. Frequent use of social media was associated with significantly greater irritability in univariate regression models (for more than once a day vs never, 1.43 points [95% CI, 1.22-1.63 points]; for most of the day vs never, 3.37 points [95% CI, 3.15-3.60 points]) and adjusted models (for more than once a day, 0.38 points [95% CI, 0.18-0.58 points]; for most of the day, 1.55 points [95% CI, 1.32-1.78 points]). These associations persisted after incorporating measures of political engagement. Conclusions and RelevanceIn this survey study of 42 597 US adults, irritability represented another correlate of social media use that merits further characterization, in light of known associations with depression and suicidality. 
    more » « less