Pub Date : 2024-09-10Epub Date: 2024-09-03DOI: 10.1073/pnas.2321965121
Matias Martinez, Tianying Cai, Beiming Yang, Zexi Zhou, Stewart A Shankman, Vijay A Mittal, Claudia M Haase, Yang Qu
The transition to adolescence is a critical period for mental health development. Socio-experiential environments play an important role in the emergence of depressive symptoms with some adolescents showing more sensitivity to social contexts than others. Drawing on recent developmental neuroscience advances, we examined whether hippocampal volume amplifies social context effects in the transition to adolescence. We analyzed 2-y longitudinal data from the Adolescent Brain Cognitive Development (ABCD®) study in a diverse sample of 11,832 youth (mean age: 9.914 y; range: 8.917 to 11.083 y; 47.8% girls) from 21 sites across the United States. Socio-experiential environments (i.e., family conflict, primary caregiver's depressive symptoms, parental warmth, peer victimization, and prosocial school environment), hippocampal volume, and a wide range of demographic characteristics were measured at baseline. Youth's symptoms of major depressive disorder were assessed at both baseline and 2 y later. Multilevel mixed-effects linear regression analyses showed that negative social environments (i.e., family conflict, primary caregiver's depressive symptoms, and peer victimization) and the absence of positive social environments (i.e., parental warmth and prosocial school environment) predicted greater increases in youth's depressive symptoms over 2 y. Importantly, left hippocampal volume amplified social context effects such that youth with larger left hippocampal volume experienced greater increases in depressive symptoms in more negative and less positive social environments. Consistent with brain-environment interaction models of mental health, these findings underscore the importance of families, peers, and schools in the development of depression during the transition to adolescence and show how neural structure amplifies social context sensitivity.
{"title":"Depressive symptoms during the transition to adolescence: Left hippocampal volume as a marker of social context sensitivity.","authors":"Matias Martinez, Tianying Cai, Beiming Yang, Zexi Zhou, Stewart A Shankman, Vijay A Mittal, Claudia M Haase, Yang Qu","doi":"10.1073/pnas.2321965121","DOIUrl":"https://doi.org/10.1073/pnas.2321965121","url":null,"abstract":"<p><p>The transition to adolescence is a critical period for mental health development. Socio-experiential environments play an important role in the emergence of depressive symptoms with some adolescents showing more sensitivity to social contexts than others. Drawing on recent developmental neuroscience advances, we examined whether hippocampal volume amplifies social context effects in the transition to adolescence. We analyzed 2-y longitudinal data from the Adolescent Brain Cognitive Development (ABCD<sup>®</sup>) study in a diverse sample of 11,832 youth (mean age: 9.914 y; range: 8.917 to 11.083 y; 47.8% girls) from 21 sites across the United States. Socio-experiential environments (i.e., family conflict, primary caregiver's depressive symptoms, parental warmth, peer victimization, and prosocial school environment), hippocampal volume, and a wide range of demographic characteristics were measured at baseline. Youth's symptoms of major depressive disorder were assessed at both baseline and 2 y later. Multilevel mixed-effects linear regression analyses showed that negative social environments (i.e., family conflict, primary caregiver's depressive symptoms, and peer victimization) and the absence of positive social environments (i.e., parental warmth and prosocial school environment) predicted greater increases in youth's depressive symptoms over 2 y. Importantly, left hippocampal volume amplified social context effects such that youth with larger left hippocampal volume experienced greater increases in depressive symptoms in more negative and less positive social environments. Consistent with brain-environment interaction models of mental health, these findings underscore the importance of families, peers, and schools in the development of depression during the transition to adolescence and show how neural structure amplifies social context sensitivity.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142126432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10Epub Date: 2024-09-03DOI: 10.1073/pnas.2311953121
Viviana Leupin, Juliane Britz
Variations in interoceptive signals from the baroreceptors (BRs) across the cardiac and respiratory cycle can modulate cortical excitability and so affect awareness. It remains debated at what stages of processing they affect awareness-related event-related potentials (ERPs) in different sensory modalities. We investigated the influence of the cardiac (systole/diastole) and the respiratory (inhalation/exhalation) phase on awareness-related ERPs. Subjects discriminated visual threshold stimuli while their electroencephalogram, electrocardiogram, and respiration were simultaneously recorded. We compared ERPs and their intracranial generators for stimuli classified correctly with and without awareness as a function of the cardiac and respiratory phase. Cyclic variations of interoceptive signals from the BRs modulated both the earliest electrophysiological markers and the trajectory of brain activity when subjects became aware of the stimuli: an early sensory component (P1) was the earliest marker of awareness for low (diastole/inhalation) and a perceptual component (visual awareness negativity) for high (systole/exhalation) BR activity, indicating that BR signals interfere with the sensory processing of the visual input. Likewise, activity spread from the primary visceral cortex (posterior insula) to posterior parietal cortices during high and from associative interoceptive centers (anterior insula) to the prefrontal cortex during low BR activity. Consciousness is thereby resolved in cognitive/associative regions when BR is low and in perceptual centers when it is high. Our results suggest that cyclic fluctuations of BR signaling affect both the earliest markers of awareness and the brain processes underlying conscious awareness.
{"title":"Interoceptive signals shape the earliest markers and neural pathway to awareness at the visual threshold.","authors":"Viviana Leupin, Juliane Britz","doi":"10.1073/pnas.2311953121","DOIUrl":"https://doi.org/10.1073/pnas.2311953121","url":null,"abstract":"<p><p>Variations in interoceptive signals from the baroreceptors (BRs) across the cardiac and respiratory cycle can modulate cortical excitability and so affect awareness. It remains debated at what stages of processing they affect awareness-related event-related potentials (ERPs) in different sensory modalities. We investigated the influence of the cardiac (systole/diastole) and the respiratory (inhalation/exhalation) phase on awareness-related ERPs. Subjects discriminated visual threshold stimuli while their electroencephalogram, electrocardiogram, and respiration were simultaneously recorded. We compared ERPs and their intracranial generators for stimuli classified correctly with and without awareness as a function of the cardiac and respiratory phase. Cyclic variations of interoceptive signals from the BRs modulated both the earliest electrophysiological markers and the trajectory of brain activity when subjects became aware of the stimuli: an early sensory component (P1) was the earliest marker of awareness for low (diastole/inhalation) and a perceptual component (visual awareness negativity) for high (systole/exhalation) BR activity, indicating that BR signals interfere with the sensory processing of the visual input. Likewise, activity spread from the primary visceral cortex (posterior insula) to posterior parietal cortices during high and from associative interoceptive centers (anterior insula) to the prefrontal cortex during low BR activity. Consciousness is thereby resolved in cognitive/associative regions when BR is low and in perceptual centers when it is high. Our results suggest that cyclic fluctuations of BR signaling affect both the earliest markers of awareness and the brain processes underlying conscious awareness.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142126453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10Epub Date: 2024-09-03DOI: 10.1073/pnas.2414877121
Laure Olazcuaga, Ruth A Hufbauer
{"title":"Evolution fails to rescue a population in an increasingly variable environment.","authors":"Laure Olazcuaga, Ruth A Hufbauer","doi":"10.1073/pnas.2414877121","DOIUrl":"https://doi.org/10.1073/pnas.2414877121","url":null,"abstract":"","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142126437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10Epub Date: 2024-09-04DOI: 10.1073/pnas.2413104121
Ryutaro Akiba, Shane Lind Boniec, Sharm Knecht, Hirofumi Uyama, Hung-Ya Tu, Takayuki Baba, Masayo Takahashi, Michiko Mandai, Rachel O Wong
The retinal fovea in human and nonhuman primates is essential for high acuity and color vision. Within the fovea lies specialized circuitry in which signals from a single cone photoreceptor are largely conveyed to one ON and one OFF type midget bipolar cell (MBC), which in turn connect to a single ON or OFF midget ganglion cell (MGC), respectively. Restoring foveal vision requires not only photoreceptor replacement but also appropriate reconnection with surviving ON and OFF MBCs and MGCs. However, our current understanding of the effects of cone loss on the remaining foveal midget pathway is limited. We thus used serial block-face electron microscopy to determine the degree of plasticity and potential remodeling of this pathway in adult Macaca fascicularis several months after acute photoreceptor loss upon photocoagulation. We reconstructed MBC structure and connectivity within and adjacent to the region of cone loss. We found that MBC dendrites within the scotoma retracted and failed to reach surviving cones to form new connections. However, both surviving cones and ON and OFF MBC dendrites at the scotoma border exhibited remodeling, suggesting that these neurons can demonstrate plasticity and rewiring at maturity. At six months postlesion, disconnected OFF MBCs clearly lost output ribbon synapses with their postsynaptic partners, whereas the majority of ON MBCs maintained their axonal ribbon numbers, suggesting differential timing or extent in ON and OFF midget circuit remodeling after cone loss. Our findings raise rewiring considerations for cell replacement approaches in the restoration of foveal vision.
人类和非人灵长类动物的视网膜眼窝对高敏锐度和色觉至关重要。眼窝内有专门的电路,其中来自单个锥体感光器的信号主要传递给一个导通型和一个关断型中层双极细胞(MBC),后者又分别连接到一个导通型或关断型中层神经节细胞(MGC)。恢复眼窝视力不仅需要更换光感受器,还需要与存活的ON型和OFF型中枢双极细胞和中枢神经节细胞进行适当的重新连接。然而,我们目前对视锥缺失对残存的眼窝侏儒通路的影响了解有限。因此,我们使用序列块面电子显微镜来确定成年猕猴在光凝后急性光感受器缺失数月后这一通路的可塑性和潜在重塑程度。我们重建了锥体缺失区域内和邻近区域的 MBC 结构和连接性。我们发现,视网膜瘤内的MBC树突回缩,无法到达存活的视锥形成新的连接。然而,幸存的锥体和位于视网膜瘤边界的导通和断开MBC树突都表现出重塑,这表明这些神经元在成熟期可以表现出可塑性和重新布线。在锥体缺失后六个月,断开连接的OFF MBC明显失去了与其突触后伙伴的输出带状突触,而大多数ON MBC保持了其轴突带状突触的数量,这表明锥体缺失后ON和OFF midget回路重塑的时间或程度不同。我们的研究结果提出了在恢复眼窝视力的细胞替代方法中重新布线的考虑因素。
{"title":"Cellular and circuit remodeling of the primate foveal midget pathway after acute photoreceptor loss.","authors":"Ryutaro Akiba, Shane Lind Boniec, Sharm Knecht, Hirofumi Uyama, Hung-Ya Tu, Takayuki Baba, Masayo Takahashi, Michiko Mandai, Rachel O Wong","doi":"10.1073/pnas.2413104121","DOIUrl":"https://doi.org/10.1073/pnas.2413104121","url":null,"abstract":"<p><p>The retinal fovea in human and nonhuman primates is essential for high acuity and color vision. Within the fovea lies specialized circuitry in which signals from a single cone photoreceptor are largely conveyed to one ON and one OFF type midget bipolar cell (MBC), which in turn connect to a single ON or OFF midget ganglion cell (MGC), respectively. Restoring foveal vision requires not only photoreceptor replacement but also appropriate reconnection with surviving ON and OFF MBCs and MGCs. However, our current understanding of the effects of cone loss on the remaining foveal midget pathway is limited. We thus used serial block-face electron microscopy to determine the degree of plasticity and potential remodeling of this pathway in adult <i>Macaca fascicularis</i> several months after acute photoreceptor loss upon photocoagulation. We reconstructed MBC structure and connectivity within and adjacent to the region of cone loss. We found that MBC dendrites within the scotoma retracted and failed to reach surviving cones to form new connections. However, both surviving cones and ON and OFF MBC dendrites at the scotoma border exhibited remodeling, suggesting that these neurons can demonstrate plasticity and rewiring at maturity. At six months postlesion, disconnected OFF MBCs clearly lost output ribbon synapses with their postsynaptic partners, whereas the majority of ON MBCs maintained their axonal ribbon numbers, suggesting differential timing or extent in ON and OFF midget circuit remodeling after cone loss. Our findings raise rewiring considerations for cell replacement approaches in the restoration of foveal vision.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142133499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Catalytic hydrogenation of CO2 to value-added fuels and chemicals is of great importance to carbon neutrality but suffers from an activity-selectivity trade-off, leading to limited catalytic performance. Herein, the ZnFeAlO4 + SAPO-34 composite catalyst was designed, which can simultaneously achieve a CO2 conversion of 42%, a CO selectivity of 50%, and a C2-C4= selectivity of 83%, resulting in a C2-C4= yield of almost 18%. This superior catalytic performance was found to be from the presence of unconventional electron-deficient tetrahedral Fe sites and electron-enriched octahedral Zn sites in the ZnFeAlO4 spinel, which were active for the CO2 deoxygenation to CO via the reverse water gas shift reaction, and CO hydrogenation to CH3OH, respectively, leading to a route for CO2 hydrogenation to C2-C4=, where the kinetics of CO2 activation can be improved, the mass transfer of CO hydrogenation can be minimized, and the C2-C4= selectivity can be enhanced via modifying the acid density of SAPO-34. Moreover, the spinel structure of ZnFeAlO4 possessed a strong ability to stabilize the active Fe and Zn sites even at elevated temperatures, resulting in long-term stability of over 450 h for this process, exhibiting great potential for large-scale applications.
催化加氢将二氧化碳转化为高附加值燃料和化学品对实现碳中和具有重要意义,但由于活性-选择性的权衡问题,催化性能受到限制。在此,我们设计了 ZnFeAlO4 + SAPO-34 复合催化剂,它可以同时实现 42% 的 CO2 转化率、50% 的 CO 选择性和 83% 的 C2-C4= 选择性,从而使 C2-C4= 收率接近 18%。研究发现,ZnFeAlO4 尖晶石中存在非常规的缺电子四面体 Fe 位点和电子富集的八面体 Zn 位点,这些位点在通过反向水气变换反应将 CO2 脱氧为 CO 以及将 CO 加氢为 CH3OH 的过程中非常活跃,因而具有优异的催化性能、通过改变 SAPO-34 的酸密度,可以改善 CO2 活化的动力学,减少 CO 加氢的传质,并提高 C2-C4= 的选择性。此外,ZnFeAlO4 的尖晶石结构即使在高温下也能很好地稳定铁和锌的活性位点,从而使该工艺的长期稳定性超过 450 小时,显示出大规模应用的巨大潜力。
{"title":"Breaking the activity-selectivity trade-off of CO<sub>2</sub> hydrogenation to light olefins.","authors":"Xiaoyue Wang, Ting Zeng, Xiaohong Guo, Zhiqiang Yan, Hongyan Ban, Ruwei Yao, Congming Li, Xiang-Kui Gu, Mingyue Ding","doi":"10.1073/pnas.2408297121","DOIUrl":"https://doi.org/10.1073/pnas.2408297121","url":null,"abstract":"<p><p>Catalytic hydrogenation of CO<sub>2</sub> to value-added fuels and chemicals is of great importance to carbon neutrality but suffers from an activity-selectivity trade-off, leading to limited catalytic performance. Herein, the ZnFeAlO<sub>4</sub> + SAPO-34 composite catalyst was designed, which can simultaneously achieve a CO<sub>2</sub> conversion of 42%, a CO selectivity of 50%, and a C<sub>2</sub>-C<sub>4</sub><sup>=</sup> selectivity of 83%, resulting in a C<sub>2</sub>-C<sub>4</sub><sup>=</sup> yield of almost 18%. This superior catalytic performance was found to be from the presence of unconventional electron-deficient tetrahedral Fe sites and electron-enriched octahedral Zn sites in the ZnFeAlO<sub>4</sub> spinel, which were active for the CO<sub>2</sub> deoxygenation to CO via the reverse water gas shift reaction, and CO hydrogenation to CH<sub>3</sub>OH, respectively, leading to a route for CO<sub>2</sub> hydrogenation to C<sub>2</sub>-C<sub>4</sub><sup>=</sup>, where the kinetics of CO<sub>2</sub> activation can be improved, the mass transfer of CO hydrogenation can be minimized, and the C<sub>2</sub>-C<sub>4</sub><sup>=</sup> selectivity can be enhanced via modifying the acid density of SAPO-34. Moreover, the spinel structure of ZnFeAlO<sub>4</sub> possessed a strong ability to stabilize the active Fe and Zn sites even at elevated temperatures, resulting in long-term stability of over 450 h for this process, exhibiting great potential for large-scale applications.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142140770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Correction to Gaffney et al., Lipid bilayer induces contraction of the denatured state ensemble of a helical-bundle membrane protein.","authors":"","doi":"10.1073/pnas.2415554121","DOIUrl":"https://doi.org/10.1073/pnas.2415554121","url":null,"abstract":"","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":11.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142165854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10Epub Date: 2024-09-05DOI: 10.1073/pnas.2411293121
Xiaoyi Liu, David Melcher, Marisa Carrasco, Nina M Hanning
The presaccadic preview of a peripheral target enhances the efficiency of its postsaccadic processing, termed the extrafoveal preview effect. Peripheral visual performance-and thus the quality of the preview-varies around the visual field, even at isoeccentric locations: It is better along the horizontal than vertical meridian and along the lower than upper vertical meridian. To investigate whether these polar angle asymmetries influence the preview effect, we asked human participants to preview four tilted gratings at the cardinals, until a central cue indicated which one to saccade to. During the saccade, the target orientation either remained or slightly changed (valid/invalid preview). After saccade landing, participants discriminated the orientation of the (briefly presented) second grating. Stimulus contrast was titrated with adaptive staircases to assess visual performance. Expectedly, valid previews increased participants' postsaccadic contrast sensitivity. This preview benefit, however, was inversely related to polar angle perceptual asymmetries; largest at the upper, and smallest at the horizontal meridian. This finding reveals that the visual system compensates for peripheral asymmetries when integrating information across saccades, by selectively assigning higher weights to the less-well perceived preview information. Our study supports the recent line of evidence showing that perceptual dynamics around saccades vary with eye movement direction.
{"title":"Presaccadic preview shapes postsaccadic processing more where perception is poor.","authors":"Xiaoyi Liu, David Melcher, Marisa Carrasco, Nina M Hanning","doi":"10.1073/pnas.2411293121","DOIUrl":"https://doi.org/10.1073/pnas.2411293121","url":null,"abstract":"<p><p>The presaccadic preview of a peripheral target enhances the efficiency of its postsaccadic processing, termed the extrafoveal preview effect. Peripheral visual performance-and thus the quality of the preview-varies around the visual field, even at isoeccentric locations: It is better along the horizontal than vertical meridian and along the lower than upper vertical meridian. To investigate whether these polar angle asymmetries influence the preview effect, we asked human participants to preview four tilted gratings at the cardinals, until a central cue indicated which one to saccade to. During the saccade, the target orientation either remained or slightly changed (valid/invalid preview). After saccade landing, participants discriminated the orientation of the (briefly presented) second grating. Stimulus contrast was titrated with adaptive staircases to assess visual performance. Expectedly, valid previews increased participants' postsaccadic contrast sensitivity. This preview benefit, however, was inversely related to polar angle perceptual asymmetries; largest at the upper, and smallest at the horizontal meridian. This finding reveals that the visual system compensates for peripheral asymmetries when integrating information across saccades, by selectively assigning higher weights to the less-well perceived preview information. Our study supports the recent line of evidence showing that perceptual dynamics around saccades vary with eye movement direction.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142140874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10Epub Date: 2024-08-26DOI: 10.1073/pnas.2403256121
Amanda L Logan, Gérard L Chouin, Adisa B Ogunfolakan, Shannon Lally, Dela Kuma, Eli Kuto, Kristina Bell, Melissa S Rosenzweig, Alemseged Beldados
This study reports the earliest directly dated occurrence of archaeological wheat and cotton in the humid forests of West Africa. These are the first archaeobotanical results from the medieval urban center of Ile-Ife, southwestern Nigeria, best known for its famous artworks. Both wheat and cotton likely spread through trans-Saharan trade networks that laid the foundation for later European trade systems. Forty-eight (48) grains of free-threshing wheat (Triticum aestivum/durum) represent the largest assemblage of wheat recovered in sub-Saharan West Africa, which is surprising given that wheat cannot be cultivated locally. Larger quantities of cotton (Gossypium sp.) recovered from late 12th- to early 13th-century CE contexts suggest earlier and more widespread use than wheat. Cotton may have been cultivated and manufactured into cloth locally. The quick adoption of these exotic crops illustrates the active negotiation of prestige through culinary and adornment practices, as well as a high degree of agricultural experimentation.
{"title":"Early archaeological evidence of wheat and cotton from medieval Ile-Ife, Nigeria.","authors":"Amanda L Logan, Gérard L Chouin, Adisa B Ogunfolakan, Shannon Lally, Dela Kuma, Eli Kuto, Kristina Bell, Melissa S Rosenzweig, Alemseged Beldados","doi":"10.1073/pnas.2403256121","DOIUrl":"https://doi.org/10.1073/pnas.2403256121","url":null,"abstract":"<p><p>This study reports the earliest directly dated occurrence of archaeological wheat and cotton in the humid forests of West Africa. These are the first archaeobotanical results from the medieval urban center of Ile-Ife, southwestern Nigeria, best known for its famous artworks. Both wheat and cotton likely spread through trans-Saharan trade networks that laid the foundation for later European trade systems. Forty-eight (48) grains of free-threshing wheat (<i>Triticum aestivum/durum</i>) represent the largest assemblage of wheat recovered in sub-Saharan West Africa, which is surprising given that wheat cannot be cultivated locally. Larger quantities of cotton (<i>Gossypium</i> sp.) recovered from late 12th- to early 13th-century CE contexts suggest earlier and more widespread use than wheat. Cotton may have been cultivated and manufactured into cloth locally. The quick adoption of these exotic crops illustrates the active negotiation of prestige through culinary and adornment practices, as well as a high degree of agricultural experimentation.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10Epub Date: 2024-09-03DOI: 10.1073/pnas.2408793121
Josué J Jautzy, Calvin Campbell, Pierre-Arnaud Desiage, Peter M J Douglas, Benjamin R Fosu, Stéphanie Larmagnat, Martine M Savard
{"title":"Diapiric controls on deep-biosphere oases: Take with a grain of salt.","authors":"Josué J Jautzy, Calvin Campbell, Pierre-Arnaud Desiage, Peter M J Douglas, Benjamin R Fosu, Stéphanie Larmagnat, Martine M Savard","doi":"10.1073/pnas.2408793121","DOIUrl":"https://doi.org/10.1073/pnas.2408793121","url":null,"abstract":"","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142126433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Free of posttransfer, on-surface synthesis (OSS) of single-atomic-layer nanostructures directly on semiconductors holds considerable potential for next-generation devices. However, due to the high diffusion barrier and abundant defects on semiconductor surfaces, extended and well-defined OSS on semiconductors has major difficulty. Furthermore, given semiconductors' limited thermal catalytic activity, initiating high-barrier reactions remains a significant challenge. Herein, using TiO2(011) as a prototype, we present an effective strategy for steering the molecule adsorption and reaction processes on semiconductors, delivering lengthy graphene nanoribbons with extendable widths. By introducing interstitial titanium (Tiint) and oxygen vacancies (Ov), we convert TiO2(011) from a passive supporting template into a metal-like catalytic platform. This regulation shifts electron density and surface dipoles, resulting in tunable catalytic activity together with varied molecule adsorption and diffusion. Cyclodehydrogenation, which is inefficient on pristine TiO2(011), is markedly improved on Tiint/Ov-doped TiO2. Even interribbon cyclodehydrogenation is achieved. The final product's dimensions, quality, and coverage are all controllable. Tiint doping outperforms Ov in producing regular and prolonged products, whereas excessive Tiint compromises molecule landing and coupling. This work demonstrates the crucial role of semiconductor substrates in OSS and advances OSS on semiconductors from an empirical trial-and-error methodology to a systematic and controllable paradigm.
{"title":"Achieving metal-like catalysis from semiconductor for on-surface synthesis.","authors":"Wenlong E, Wei Yi, Honghe Ding, Junfa Zhu, Federico Rosei, Xueming Yang, Miao Yu","doi":"10.1073/pnas.2408919121","DOIUrl":"https://doi.org/10.1073/pnas.2408919121","url":null,"abstract":"<p><p>Free of posttransfer, on-surface synthesis (OSS) of single-atomic-layer nanostructures directly on semiconductors holds considerable potential for next-generation devices. However, due to the high diffusion barrier and abundant defects on semiconductor surfaces, extended and well-defined OSS on semiconductors has major difficulty. Furthermore, given semiconductors' limited thermal catalytic activity, initiating high-barrier reactions remains a significant challenge. Herein, using TiO<sub>2</sub>(011) as a prototype, we present an effective strategy for steering the molecule adsorption and reaction processes on semiconductors, delivering lengthy graphene nanoribbons with extendable widths. By introducing interstitial titanium (Ti<sub>int</sub>) and oxygen vacancies (O<sub>v</sub>), we convert TiO<sub>2</sub>(011) from a passive supporting template into a metal-like catalytic platform. This regulation shifts electron density and surface dipoles, resulting in tunable catalytic activity together with varied molecule adsorption and diffusion. Cyclodehydrogenation, which is inefficient on pristine TiO<sub>2</sub>(011), is markedly improved on Ti<sub>int</sub>/O<sub>v</sub>-doped TiO<sub>2</sub>. Even interribbon cyclodehydrogenation is achieved. The final product's dimensions, quality, and coverage are all controllable. Ti<sub>int</sub> doping outperforms O<sub>v</sub> in producing regular and prolonged products, whereas excessive Ti<sub>int</sub> compromises molecule landing and coupling. This work demonstrates the crucial role of semiconductor substrates in OSS and advances OSS on semiconductors from an empirical trial-and-error methodology to a systematic and controllable paradigm.</p>","PeriodicalId":20548,"journal":{"name":"Proceedings of the National Academy of Sciences of the United States of America","volume":null,"pages":null},"PeriodicalIF":9.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142143332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}