PNAS nexus最新文献

Thermodynamic signatures of diagonal nematicity in RbFe₂As₂ superconductor.

IF 2.2

PNAS nexus Pub Date : 2025-04-04 eCollection Date: 2025-04-01 DOI: 10.1093/pnasnexus/pgaf060

Yuta Mizukami, Ohei Tanaka, Kousuke Ishida, Asato Onishi, Yoichi Kageyama, Masaya Tsujii, Ryotaro Ohno, Noriaki Kimura, Takaya Mitsui, Shinji Kitao, Masayuki Kurokuzu, Makoto Seto, Shigeyuki Ishida, Akira Iyo, Hiroshi Eisaki, Kenichiro Hashimoto, Takasada Shibauchi

{"title":"Thermodynamic signatures of diagonal nematicity in RbFe2As2 superconductor.","authors":"Yuta Mizukami, Ohei Tanaka, Kousuke Ishida, Asato Onishi, Yoichi Kageyama, Masaya Tsujii, Ryotaro Ohno, Noriaki Kimura, Takaya Mitsui, Shinji Kitao, Masayuki Kurokuzu, Makoto Seto, Shigeyuki Ishida, Akira Iyo, Hiroshi Eisaki, Kenichiro Hashimoto, Takasada Shibauchi","doi":"10.1093/pnasnexus/pgaf060","DOIUrl":"10.1093/pnasnexus/pgaf060","url":null,"abstract":"Electronic nematic states, characterized by broken rotational symmetry, are prevalent in correlated materials. In most iron-based superconductors, the nematic anisotropy aligns with the Fe-Fe direction of the iron square lattice. However, recent investigations propose a unique form of nematicity oriented along the diagonal Fe-As direction in heavily hole-doped <math><mi>A</mi> <msub><mrow><mi>Fe</mi></mrow> <mn>2</mn></msub> <msub><mrow><mi>As</mi></mrow> <mn>2</mn></msub> </math> ( <math><mi>A</mi> <mo>=</mo> <mrow><mi>Rb</mi></mrow> </math> or Cs). Yet, the transport studies focusing on the fluctuations of such nematicity yield conflicting outcomes regarding the presence and orientation of the nematic fluctuations. Here, we report high-resolution heat capacity measurements conducted under in-plane field rotation in <math> <msub><mrow><mi>RbFe</mi></mrow> <mn>2</mn></msub> <msub><mrow><mi>As</mi></mrow> <mn>2</mn></msub> </math> . While no discernible anomaly associated with the nematic transition is found in the temperature dependence of specific heat, the field-angle dependence near the superconducting transition (at <math><mo>∼</mo> <mn>2.8</mn></math> K) reveals clear 2-fold oscillations within the plane, providing thermodynamic evidence for the presence of diagonal nematicity. Moreover, we find that Mössbauer spectroscopy sensitively probes the nematic transition at <math><mo>∼</mo> <mn>50</mn></math> K with no evidence of static magnetism. These findings imply that the diagonal nematicity in <math> <msub><mrow><mi>RbFe</mi></mrow> <mn>2</mn></msub> <msub><mrow><mi>As</mi></mrow> <mn>2</mn></msub> </math> has a distinct mechanism involving charge degrees of freedom, exhibiting unusual thermodynamic properties of the transition.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 4","pages":"pgaf060"},"PeriodicalIF":2.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11969064/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143797376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hormonal dynamics reveal a stimulatory role for secretoneurin in zebrafish ovulation.

IF 2.2

PNAS nexus Pub Date : 2025-04-04 eCollection Date: 2025-04-01 DOI: 10.1093/pnasnexus/pgaf097

Di Peng, Chunyu Lu, Victoria Spadacini, Kimberly Mitchell, Yongjun Tan, Dapeng Zhang, Berta Levavi-Sivan, Wei Hu, Vance L Trudeau

{"title":"Hormonal dynamics reveal a stimulatory role for secretoneurin in zebrafish ovulation.","authors":"Di Peng, Chunyu Lu, Victoria Spadacini, Kimberly Mitchell, Yongjun Tan, Dapeng Zhang, Berta Levavi-Sivan, Wei Hu, Vance L Trudeau","doi":"10.1093/pnasnexus/pgaf097","DOIUrl":"10.1093/pnasnexus/pgaf097","url":null,"abstract":"Surge release of luteinizing hormone (Lh) from the pituitary is essential for fertility as it triggers ovulation. While secretoneurin (SN) is a phylogenetically conserved secretogranin-2-derived peptide that stimulates Lh, its role in ovulation has not been established. To directly compare periovulatory changes in the classical hormones to the emerging reproductive neuropeptides SNa and SNb, simultaneous mass spectrometry measurement of 9 peptides and 5 steroids was conducted in female zebrafish. Regression analysis indicated that levels of SNa1-34 in the brain peaked when type 3 gonadotropin-releasing hormone (Gnrh3) increased (R 2 = 0.71) at the time of the Lh surge, 3.5 h before ovulation. Levels of the naturally occurring derivative SNa1-14 were highest at ovulation, while SNb1-31 was invariable. The bioactivities of SNa1-34 and SNa1-14 were investigated. After injection of SNa1-34 in females that had been isolated from males, 61% (11/18) ovulated within 6 h, which was like the effects of the Lh analog human chorionic gonadotropin (72%; 13/18 females). SNa1-34 injection induces ovulation by increasing time-dependent expression of gnrh3 in the brain, a likely direct stimulation of chorionic gonadotropin alpha (cga) and luteinizing hormone b (lhb) subunit in pituitary, and via the subsequent time-dependent increase in nuclear progesterone receptor (npr) in ovaries. In contrast, SNa1-14 exhibited far fewer effects on gene expression and did not induce ovulation. Our results support the proposal that SN is a reproductive hormone.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 4","pages":"pgaf097"},"PeriodicalIF":2.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11969067/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143797396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Are chatbots reliable text annotators? Sometimes. 聊天机器人是可靠的文本注释器吗？有时

IF 2.2

PNAS nexus Pub Date : 2025-04-01 DOI: 10.1093/pnasnexus/pgaf069

Ross Deans Kristensen-McLachlan, Miceal Canavan, Marton Kárdos, Mia Jacobsen, Lene Aarøe

{"title":"Are chatbots reliable text annotators? Sometimes.","authors":"Ross Deans Kristensen-McLachlan, Miceal Canavan, Marton Kárdos, Mia Jacobsen, Lene Aarøe","doi":"10.1093/pnasnexus/pgaf069","DOIUrl":"10.1093/pnasnexus/pgaf069","url":null,"abstract":"Recent research highlights the significant potential of ChatGPT for text annotation in social science research. However, ChatGPT is a closed-source product, which has major drawbacks with regards to transparency, reproducibility, cost, and data protection. Recent advances in open-source (OS) large language models (LLMs) offer an alternative without these drawbacks. Thus, it is important to evaluate the performance of OS LLMs relative to ChatGPT and standard approaches to supervised machine learning classification. We conduct a systematic comparative evaluation of the performance of a range of OS LLMs alongside ChatGPT, using both zero- and few-shot learning as well as generic and custom prompts, with results compared with supervised classification models. Using a new dataset of tweets from US news media and focusing on simple binary text annotation tasks, we find significant variation in the performance of ChatGPT and OS models across the tasks and that the supervised classifier using DistilBERT generally outperforms both. Given the unreliable performance of ChatGPT and the significant challenges it poses to Open Science, we advise caution when using ChatGPT for substantive text annotation tasks.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 4","pages":"pgaf069"},"PeriodicalIF":2.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11954583/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143765931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Generative propaganda: Evidence of AI's impact from a state-backed disinformation campaign.

IF 2.2

PNAS nexus Pub Date : 2025-04-01 DOI: 10.1093/pnasnexus/pgaf083

Morgan Wack, Carl Ehrett, Darren Linvill, Patrick Warren

{"title":"Generative propaganda: Evidence of AI's impact from a state-backed disinformation campaign.","authors":"Morgan Wack, Carl Ehrett, Darren Linvill, Patrick Warren","doi":"10.1093/pnasnexus/pgaf083","DOIUrl":"10.1093/pnasnexus/pgaf083","url":null,"abstract":"Can AI bolster state-backed propaganda campaigns, in practice? Growing use of AI and large language models has drawn attention to the potential for accompanying tools to be used by malevolent actors. Though recent laboratory and experimental evidence has substantiated these concerns in principle, the usefulness of AI tools in the production of propaganda campaigns has remained difficult to ascertain. Drawing on the adoption of generative-AI techniques by a state-affiliated propaganda site with ties to Russia, we test whether AI adoption enabled the website to amplify and enhance its production of disinformation. First, we find that the use of generative-AI tools facilitated the outlet's generation of larger quantities of disinformation. Second, we find that use of generative-AI coincided with shifts in the volume and breadth of published content. Finally, drawing on a survey experiment comparing perceptions of articles produced prior to and following the adoption of AI tools, we show that the AI-assisted articles maintained their persuasiveness in the postadoption period. Our results illustrate how generative-AI tools have already begun to alter the size and scope of state-backed propaganda campaigns.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 4","pages":"pgaf083"},"PeriodicalIF":2.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11950819/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143765938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Polychlorinated biphenyls induce immunometabolic switch of antiinflammatory macrophages toward an inflammatory phenotype.

IF 2.2

PNAS nexus Pub Date : 2025-03-27 eCollection Date: 2025-04-01 DOI: 10.1093/pnasnexus/pgaf100

Riley M Behan-Bush, Michael V Schrodt, Elizabeth Kilburg, Jesse N Liszewski, Laura M Bitterlich, Karen English, Aloysius J Klingelhutz, James A Ankrum

{"title":"Polychlorinated biphenyls induce immunometabolic switch of antiinflammatory macrophages toward an inflammatory phenotype.","authors":"Riley M Behan-Bush, Michael V Schrodt, Elizabeth Kilburg, Jesse N Liszewski, Laura M Bitterlich, Karen English, Aloysius J Klingelhutz, James A Ankrum","doi":"10.1093/pnasnexus/pgaf100","DOIUrl":"10.1093/pnasnexus/pgaf100","url":null,"abstract":"Polychlorinated biphenyls (PCBs) are a group of environmental toxicants associated with increased risk of diabetes, obesity, and metabolic syndrome. These metabolic disorders are characterized by systemic and local inflammation within adipose tissue, the primary site of PCB accumulation. These inflammatory changes arise when resident adipose tissue macrophages undergo phenotypic plasticity-switching from an antiinflammatory to an inflammatory phenotype. Thus, we sought to assess whether PCB exposure drives macrophage phenotypic switching. We investigated how human monocyte-derived macrophages polarized toward an M1, M2a, or M2c phenotype were impacted by exposure to Aroclor 1254, a PCB mixture found at high levels in school air. We showed that PCB exposure not only exacerbates the inflammatory phenotype of M1 macrophages but also shifts both M2a and M2c cells toward a more inflammatory phototype in both a dose- and time-dependent manner. Additionally, we show that PCB exposure leads to significant metabolic changes. M2 macrophages exposed to PCBs exhibit increased reliance on aerobic glycolysis and reduced capacity for fatty acid and amino acid oxidation-both indicators of an inflammatory macrophage phenotype. Collectively, these results demonstrate that PCBs promote immunometabolic macrophage plasticity toward a more M1-like phenotype, thereby suggesting that PCBs exacerbate metabolic diseases by altering the inflammatory environment in adipose tissue.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 4","pages":"pgaf100"},"PeriodicalIF":2.2,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11969150/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143797374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Disentangling dynamic information and temporal order processing of human action perception.

IF 2.2

PNAS nexus Pub Date : 2025-03-24 eCollection Date: 2025-03-01 DOI: 10.1093/pnasnexus/pgaf067

Vojtěch Smekal, Marta Poyo Solanas, Beatrice de Gelder

{"title":"Disentangling dynamic information and temporal order processing of human action perception.","authors":"Vojtěch Smekal, Marta Poyo Solanas, Beatrice de Gelder","doi":"10.1093/pnasnexus/pgaf067","DOIUrl":"10.1093/pnasnexus/pgaf067","url":null,"abstract":"Human action perception involves processing dynamic information in its temporal order. However, previous studies investigating action perception have not yet distinguished between the presence of dynamic information and the temporal order in which dynamic information unfolds within the context of a single action. Using 3-T functional MRI, we presented participants with brief, single-actor, whole-body actions viewed either as still images, as intact videos, or as videos consisting of short dynamic fragments with the order temporally scrambled. Regions classically associated with action perception showed higher activity for dynamic compared with still stimuli, regardless of the temporal continuity in the dynamic stimuli. However, two clusters in the right inferior parietal lobule (IPL) differentiated between the intact and temporally scrambled videos. Specifically, the right angular gyrus (AG) showed a preference for the intact videos over the temporally scrambled ones, while the right supramarginal gyrus (SMG) showed the opposite pattern. Combined with previous literature, we argue for the role of the IPL as a temporospatial buffer, with the SMG processing dynamic information on short timescales and the AG processing on longer timescales. Our results underscore the need to consider dynamic information and temporal order separately in investigations of action perception.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 3","pages":"pgaf067"},"PeriodicalIF":2.2,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11931616/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correction to: Mass shootings durably increase the sale of alcohol in American communities.

IF 2.2

PNAS nexus Pub Date : 2025-03-24 eCollection Date: 2025-03-01 DOI: 10.1093/pnasnexus/pgaf098

引用次数: 0

Precision spatiotemporal analysis of large-scale compound-protein interactions through molecular dynamics simulation.

IF 2.2

PNAS nexus Pub Date : 2025-03-22 eCollection Date: 2025-03-01 DOI: 10.1093/pnasnexus/pgaf094

Shigeyuki Matsumoto, Yuta Isaka, Ryo Kanada, Biao Ma, Mitsugu Araki, Shuntaro Chiba, Atsushi Tokuhisa, Hiroaki Iwata, Shoichi Ishida, Yoshinobu Akinaga, Kei Terayama, Ryosuke Kojima, Yohei Harada, Kazuhiro Takemura, Teruki Honma, Akio Kitao, Yasushi Okuno

{"title":"Precision spatiotemporal analysis of large-scale compound-protein interactions through molecular dynamics simulation.","authors":"Shigeyuki Matsumoto, Yuta Isaka, Ryo Kanada, Biao Ma, Mitsugu Araki, Shuntaro Chiba, Atsushi Tokuhisa, Hiroaki Iwata, Shoichi Ishida, Yoshinobu Akinaga, Kei Terayama, Ryosuke Kojima, Yohei Harada, Kazuhiro Takemura, Teruki Honma, Akio Kitao, Yasushi Okuno","doi":"10.1093/pnasnexus/pgaf094","DOIUrl":"10.1093/pnasnexus/pgaf094","url":null,"abstract":"Biological systems are composed of and regulated by intricate and diverse biomolecular interactions. Experimental and computational approaches have been developed to elucidate the mechanisms of these interactions; however, owing to cost, time, and accuracy issues, large-scale spatiotemporal analyses of molecular pairs remain challenging. Thus, the molecular recognition mechanisms underlying these diverse interactions remain unclear. We successfully simulated the large-scale molecular dynamics (MD) of 4,275 protein-compound pairs by combining a method to accelerate the MD simulations with the supercomputer Fugaku. Our spatiotemporal analysis of generated big MD data revealed universal features underlying molecular recognition and binding processes. This study expands our understanding of the concept of MD simulations from a technique to investigate the dynamic properties of individual protein-drug pairs to an approach to perform large-scale spatiotemporal analysis and compound screening. This study opens an avenue in biological research for subsequent drug discovery.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 3","pages":"pgaf094"},"PeriodicalIF":2.2,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11949864/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143756402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessing the capacity of agricultural research and development to increase the stability of global crop yields under climate change.

IF 2.2

PNAS nexus Pub Date : 2025-03-22 eCollection Date: 2025-04-01 DOI: 10.1093/pnasnexus/pgaf099

Toshichika Iizumi, Toru Sakai, Yoshimitsu Masaki, Kei Oyoshi, Takahiro Takimoto, Hideo Shiogama, Yukiko Imada, David Makowski

{"title":"Assessing the capacity of agricultural research and development to increase the stability of global crop yields under climate change.","authors":"Toshichika Iizumi, Toru Sakai, Yoshimitsu Masaki, Kei Oyoshi, Takahiro Takimoto, Hideo Shiogama, Yukiko Imada, David Makowski","doi":"10.1093/pnasnexus/pgaf099","DOIUrl":"10.1093/pnasnexus/pgaf099","url":null,"abstract":"Agricultural research and development (R&D) has increased crop yields, but little is known about its ability to increase yield stability in the context of increasingly frequent extreme weather events. Using a grid yield dataset, we show that from 2000 to 2019, the SD of yield anomalies for maize, rice, wheat, and soybean increased in 20% of the global harvested area. Based on random forest models relating yield anomaly to climate, soil, management, and public R&D expenditure, we show that cumulative agricultural R&D expenditure, proportion of growing season exposed to optimal hourly temperatures, and dry and very wet days are key factors explaining crop yield variability. An attribution analysis based on large ensemble climate simulations with and without human influence on the global climate shows that unfavorable agroclimatic conditions due to climate change has increased SD, while higher R&D expenditure has led to more contrasting trends in SD over 2000-2019. Although R&D has continued steadily in most countries, this study indicates that the progress made in R&D since 2000 may have lagged behind the unfavorable effect of climate change on yield variability.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 4","pages":"pgaf099"},"PeriodicalIF":2.2,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11969147/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143797395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unraveling biomolecular and community grammars of RNA granules via machine learning.

IF 2.2

PNAS nexus Pub Date : 2025-03-19 eCollection Date: 2025-04-01 DOI: 10.1093/pnasnexus/pgaf093

Zhan Ban, Yuchen Lin, Yan Yan, Kenneth A Dawson

引用次数: 0