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Mechanisms of fast CO2 fixation reaction by enoyl-CoA carboxylases/reductase
(European Synchrotron Radiation Facility, 2028-01-01) Chretien, Anaïs; Ertem Kuzucu, Fatma Betul; Summers, Jacob; Wranik, Maximilian; 0000-0001-8480-1443; 0000-0002-2144-989x; 0000-0003-3113-0353; 0000-0002-2482-0164
Carbon dioxide (CO2) is an atmospheric greenhouse gas that feeds all life, plays a critical role in global warming, and could constitute an inexpensive carbon source for future sustainable industries. While synthetic chemistry lacks suitable catalysts to functionalize carbon dioxide in mild reaction conditions, autotrophs do it constantly, and thus there is increasing interest in exploiting the CO2-fixation mechanisms offered by nature. In this exchange proposal, we propose fast time-resolved structural-dynamics studies of one of the fastest CO2-fixation enzymes, enoyl-CoA carboxylase/reductase (ECR), using ambient temperature serial X-ray crystallography on Beamline ID29, ESRF, which achieves 10μs resolution. This study will reveal details of the enzyme subunit coupling as well as the enzyme-substrate interactions to correlate the structural and functional states of the enzyme during fixation and pave the way for faster biomolecule productions using engineered C-cycling enzymes.
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Mechanisms of fast CO2 fixation reaction by enoyl-CoA carboxylases/reductase
(European Synchrotron Radiation Facility, 2027-01-01) Summers, Jacob; Sanctis, Daniele; Vlahakis, Niko; Knight, Victoria; Ertem Kuzucu, Fatma Betul; Chretien, Anaïs; Nurizzo, Didier; 0000-0003-3113-0353; 0000-0003-0391-8290; 0000-0002-5092-0265; 0000-0002-2144-989x; 0000-0001-8480-1443; 0000-0002-7367-5098
Carbon dioxide (CO2) is an atmospheric greenhouse gas that feeds all life, plays a critical role in global warming, and could constitute an inexpensive carbon source for future sustainable industries. While synthetic chemistry lacks suitable catalysts to functionalize carbon dioxide in mild reaction conditions, autotrophs do it constantly, and thus there is increasing interest in exploiting the CO2-fixation mechanisms offered by nature. In this exchange proposal, we propose fast time-resolved structural-dynamics studies of one of the fastest CO2-fixation enzymes, enoyl-CoA carboxylase/reductase (ECR), using ambient temperature serial X-ray crystallography on Beamline ID29, ESRF, which achieves 10μs resolution. This study will reveal details of the enzyme subunit coupling as well as the enzyme-substrate interactions to correlate the structural and functional states of the enzyme during fixation and pave the way for faster biomolecule productions using engineered C-cycling enzymes.
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An application of the interpersonal theory of suicide in relation to sexual orientation : the moderating effects of problem-solving and social support
(Koç University, 2025-12-11) Master Student, Aksu, Ece Tilbe; Eskin, Mehmet; Graduate School of Social Sciences and Humanities; Psychology; Acartürk, Ceren; Atalay, Ayşe Altan; GRADUATE SCHOOL OF SOCIAL SCIENCES AND HUMANITIES
Suicide is a global cause of death and disability. Its complex nature underscores the importance of understanding the psychological factors that contribute to suicidal behavior across diverse populations and highlights the need for culturally sensitive research. The Interpersonal Theory of Suicide (IPTS) is a well-known framework for understanding suicidal behavior through its central concepts: perceived burdensomeness (PB), thwarted belongingness (TB), and acquired capability for suicide (ACS). However, empirical investigations of this theory remain scarce in non-Western contexts and among sexual minority populations, which face elevated risk. The present study aimed to examine the applicability of the IPTS within a Turkish sample comprising both heterosexual and non-heterosexual individuals. Guided by the minority stress framework, it was hypothesized that interpersonal risk factors would mediate the relationship between sexual orientation and suicidal ideation. Additionally, social problem-solving skills (SPSS) and perceived social support (PSS) were expected to serve as protective factors. A total of 383 participants aged 18 to 35 (M = 25.72, SD = 4.16), including both heterosexual and non-heterosexual individuals, completed an online questionnaire. Results indicated that both TB and PB significantly predicted suicidal ideation, whereas suicide attempts were individually associated with TB and FAD. TB mediated the link between sexual orientation and suicidal ideation, whereas PB did not. SPSS emerged as a protective factor, attenuating the negative effects of both PB and TB on suicidal ideation, whereas PSS similarly moderated the impact of PB.The findings support the cultural applicability of the IPTS in this mixed sample and highlight the importance of both interpersonal and structural interventions to effectively reduce suicide risk.
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PublicationOpen Access
Fine tools for fine work. The form and function of ‘Small Craft Tools’ from Bronze Age Kaymakçı (Türkiye)
(Univerzita Karlova, Filozofická fakulta, 2025-08-26) Faculty Member, Roosevelt, Christopher; PhD Student, Kaner, Tunç; Schaupp, Kathleen C.; Pieniążek, Magda; ANAMED (Koç University Research Center for Anatolian Civilizations); Research Center; ANAMED
Tools have always played an extremely important, defining role in human life. A closer look at Small Craft Tools (SCTs), such as drills, awls, punches, and small chisels, not only allows us an insight into the exact production techniques of artefacts but can also provide information on regional exchanges of goods and craft specializations in individual settlements. Nevertheless, these artefacts have been largely neglected in previous studies, and there seems to be no agreement among the few authors who have described such small bronze tools in more detail. The large number of middle and late Bronze Age SCTs found at Kaymakçı (Türkiye) was used as an opportunity to study their typology, characteristics, and use -wear. A total of 31 SCTs were found in only six years of excavation (2014–2021). In relation to the years of excavation, this is comparable to the number of SCTs found at Hattusa. This indicates the importance of Kaymakçı as a potential leather/textile production center. This study describes and characterizes the SCTs from Kaymakçı in detail. The authors are able to identify distinct differences between these tools and make suggestions for a more unified classification, underlining that such items are worthy of closer consideration in future studies.
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PublicationOpen Access
Drinking with animals: investigating zoomorphic decorations on second-millennium BCE Western Anatolian pottery
(Consiglio Nazionale delle Ricerche, 2025-08-25) Faculty Member, Roosevelt, Christopher; PhD Student, Kaner, Tunç; Bobik, Ján; Pavúk, Peter; Department of Archaeology and History of Art; ANAMED (Koç University Research Center for Anatolian Civilizations); College of Social Sciences and Humanities; Research Center
This study provides the first comprehensive analysis of zoomorphic plastic decorations on pottery from second-millennium BCE western Anatolia. Despite early observations by Heinrich Schliemann at Troy, these decorations have not been systematically studied until now. This research addresses a gap in figural iconographic material from western Anatolia, contrasted with the rich iconography of neighboring regions. Over 300 zoomorphic decorations of the second millennium BCE from western Anatolia are categorized and described. The chronological and geographical situation and changes over time of seven types are discussed across four recognized phases. Moreover, the article highlights similarities and possible links with central Anatolia, the Aegean, and Italy. It underscores the cultural and symbolic significance of these decorations, suggesting their role in ritual and economic contexts. Finally, the article also contributes to deeper understandings of western Anatolian material culture and its interactions with neighboring regions.