syn Getting in Synch: Understanding Student Perceptions of Synchronous Online Instruction By Published On :: 2022-12-09 Aim/Purpose: This study examines the impact of transitioning from in-person classrooms to remote online business education and provides analysis of key factors impacting course and instructor ratings as well as strategies for higher education institutions to provide engaging instruction. Background: “Zoom”ing into teaching and moving out of traditional classrooms during the COVID-19 pandemic has been a path full of twists and has impacted student perceptions of courses as well as instructors. One challenge has been to make the quality of synchronous online instruction perceived by students as positive as classroom-delivered ones. Methodology: We analyze primary data collected in the course evaluation process from Business & Accounting students over six semesters between Fall 2019 to Spring 2022, covering pre-pandemic instruction in the classroom and the conversion to virtual instruction via Zoom. A total of 1782 observations for 38 courses were examined using mean comparison, regression and correlation analyses, and pairwise comparisons. Contribution: We provide insights from the evaluation of those instructors who were able to make their Zoom-delivered courses perceived by students as equivalent or better than room-delivered ones. Specifically, clear presentation, stimulating delivery, providing feedback and encouraging discussion were positively correlated with successful online classes. Findings: We find that there is a clear downward shift in course and instructor ratings as the change to synchronous online delivery was made. However, in the Spring of 2022, even though instructors and students were still not completely back in the classroom, both instructor and course ratings moved back closer to the pre-pandemic levels. The parameters associated with instructor ratings, such as providing feedback, clear presentations, stimulating sessions, and encouraging discussion, showed similar downward fluctuations. Also, aspects related to course content were affected by the transition to online modality, including training on critical thinking quantitative analysis, research and writing abilities, and overall usefulness of the content. Moore’s model of Transactional Distance helps explain these changes. Recommendations for Practitioners: We recommend that practitioners allow sufficient time for students and faculty to learn through online instruction delivery and supply training for both populations in adapting to learning in this delivery mode. Recommendation for Researchers: The disruption in higher education caused by COVID-19 has provided a wealth of information on the pluses and minuses of online delivery. Careful inspection of trends can help provide guidance to higher education leaders. Impact on Society: One of the many changes the COVID-19 pandemic brought was the opportunity to try alternate ways of connecting and learning. This study shows how this experience can be used to guide the future of higher education. Future Research: Further research is needed to explore the in-depth reactions of students and faculty to the switch from classroom to online delivery, to explore whether these findings can be more broadly applied to other subjects and other types of universities. Full Article
syn Building a Framework to Support Project-Based Collaborative Learning Experiences in an Asynchronous Learning Network By Published On :: Full Article
syn How Do Students View Asynchronous Online Discussions As A Learning Experience? By Published On :: Full Article
syn Using Photos and Visual-Processing Assistive Technologies to Develop Self-Expression and Interpersonal Communication of Adolescents with Asperger Syndrome (AS) By Published On :: Full Article
syn Synthesizing Design and Informing Science Rationales for Driving a Decentralized Generative Knowledge Management Agenda By Published On :: 2019-04-11 Aim/Purpose: In a world of rapidly expanding complexity and exponentially increasing data availability, IT-based knowledge management tools will be needed to manage and curate available information. This paper looks at a particular tool architecture that has been previously proposed: The Personal Knowledge Management System (PKMS). The specific focus is on how the proposed architecture conforms to design science principles that relate to how it is likely to evolve. Background: We first introduce some recent informing science and design science research frameworks, then examine how the PKMS architecture would conform to these. Methodology: The approach taken is conceptual analysis. Contribution: The analysis provides a clearer understanding of how the proposed PKMS would serve the diverse-client ambiguous-target (DCAT) informing scenario and how it could be expected to evolve. Findings: We demonstrate how the PKMS informing architecture can be characterized as a “social machine” that appears to conform to a number of principles that would facilitate its long-term evolution. Future Research: The example provided by the paper could serve as a model future research seeking to integrate design science and informing science in the study of IT artefacts. Full Article
syn Local Partnering in Foreign Ventures: Uncertainty, Experiential Learning, and Syndication in Cross-Border Venture Capital Investments By amj.aom.org Published On :: Thu, 14 May 2015 16:16:41 +0000 If partnering with local firms is an intuitive strategy with which to mitigate uncertainty in foreign ventures, then why don't organizations always partner with local firms, especially in uncertain settings? We address this question by unbundling the effects of uncertainty in foreign ventures at the venture and country levels. We contend that, while both levels increase the need for partnering with local firms in foreign ventures, country-level uncertainty increases the difficulty of partnering with local firms and decreases the likelihood of such partnerships. We also posit that experiential learning helps firms manage the two types of uncertainty, and thereby reduces the need for partnering—yet, experience in the host country makes partnering more feasible and increases the likelihood of such partnerships. To test our hypotheses, we conceptualize the decision to partner with a local firm in a foreign venture as a multilayered decision, and model it accordingly. Using a global sample of venture capital investments made between 1984 and 2011, we find support for the distinct effects of venture- and country-level uncertainty as well as for corresponding levels of experiential learning. These findings have implications for the literature on cross-border venture capital investment and international business in general. Full Article
syn After the Break-Up: The Relational and Reputational Consequences of Withdrawals from Venture Capital Syndicates By amj.aom.org Published On :: Thu, 10 Sep 2015 15:15:25 +0000 Organizational theorists are increasingly interested in the antecedents of terminating interorganizational relationships, but have paid little attention to the disruptive consequences of such terminations on future tie formation. To redress this imbalance, the present study focuses on how venture capital (VC) firms' withdrawals from VC syndicates are associated with their subsequent syndication over the 1985 through 2008 period. We argue that withdrawals disrupt the relationships of the withdrawing VC firms with the coinvestors and reduce the likelihood of them entering into subsequent exchange (relational consequences). Furthermore, public information on the withdrawals can undermine the withdrawing VC firm's reputation for reliability, making it a less desirable exchange partner overall (global reputational consequences). Finally, we find that abandoned coinvestors can spread negative, private information about the withdrawing firm, reducing its chances of syndication with their other network contacts (local reputational consequences). We also show that the global and local reputational consequences attenuate each other, due to redundancy in the content of information each provides. We discuss the implications of our theory for the research on network dynamics and reputation. Full Article
syn Di-O-Matic announces Lipsync MX Public Beta By www.di-o-matic.com Published On :: 10 Nov 2004 16:08:38 GMT Full Article
syn Immediate Availability of LipSync MX By www.di-o-matic.com Published On :: 16 Dec 2004 16:08:38 GMT Full Article
syn Immediate Availability of LipSync MX 2 By www.di-o-matic.com Published On :: 29 Aug 2006 16:08:38 GMT Full Article
syn Di-O-Matic announces LipSync MX 2.5 By www.di-o-matic.com Published On :: 22 Mar 2007 16:08:38 GMT Full Article
syn Immediate Availability of LipSync MX v3 By www.di-o-matic.com Published On :: 8 Jul 2008 16:08:38 GMT Full Article
syn Immediate Availlability of LipSync MX v4 By www.di-o-matic.com Published On :: 8 Jun 2011 06:00:00 GMT Full Article
syn Letter to the editor: Pray for Trump Derangement Syndrome sufferers By www.washingtontimes.com Published On :: Thu, 07 Nov 2024 09:12:03 -0500 If what former ABC News journalist Mark Halperin said last month about there being a national mental health crisis in the event of a second Trump presidency, as a "deplorable" I want to ensure that my friends and relatives suffering from Trump Derangement Syndrome stay fully calm. Full Article
syn Biodiversity and Food Security – From Trade-offs to Synergies By www.eubon.eu Published On :: Thu, 29 May 2014 09:54:00 +0300 3rd International Conference on Biodiversity and the UN Millennium Development Goals - October 29-31, 2014, Aix-en-Provence, France This international conference is the third in a series, organized by the French CNRSInstitut Ecologie et Environnement (InEE) and the German Leibniz Association (WGL). The goal is to identify science-based solutions for global sustainability focusing on the issues of biodiversity and food security. Current ecological, economic and societal challenges for development require a holistic understanding of food security and environmental management: from this perspective, biodiversity can be seen as key to overcome trade-offs and to develop synergies between the food system and the conservation of landscapes, ecosystems, and species. The conference seeks to attract scientists from basic and applied research. It involves policy makers and other stakeholders concerned with biodiversity and food security themes who are interested in developing new solutions and strategies. It will connect researchers and stakeholders from natural sciences, social sciences, economics, humanities, technology and related fields. Full Article News
syn Biodiversity and Food Security – From Trade-offs to Synergies By www.eubon.eu Published On :: Fri, 22 Aug 2014 16:21:00 +0300 The 3rd International Conference on Biodiversity and the UN Millennium Development Goals will take place between October 29-31, 2014 in Aix-en-Provence, France. under the tematic title "Biodiversity and Food Security – From Trade-offs to Synergies". This conference is the third in a series, organized by the French CNRS Institut Ecologie et Environnement (InEE) and the German Leibniz Association (WGL). The conference is based on invited keynotes and contributed posters for any of the topics relevant to the conference theme. Keynote speakers are now confirmed, including Professor José Sarukhán, UNAM, México, and Professor Jacqueline McGlade, UNEP, Nairobi. Across scales from genes to species, landscapes and biomes, biodiversity is an important resource for humanity. It is the key for a broad range of services provided by ecosystems. Biodiversity helps regulate the nutrient cycle, water (e.g. floods) and mitigates impacts of climate change. Biodiversity is also of direct importance for human well-being and for cultural and other values including recreation. The provisioning of clean water and diverse food supply makes it vital for all people. Biodiversity at all levels, including the diversity of genes, species and ecosystems, is lost at alarming rates. Critical factors for these trends are habitat destruction, global warming and the uncontrolled spread of alien species. Pollution, nitrogen deposition and shifts in precipitation further affect biodiversity. Food security faces significant challenges due to population growth, poverty, globalization, climate change and other factors. Supplying healthy food to all citizens is crucial for global development - to reach it, not only food production but also equitable access to food for all people must be improved substantially. Biodiversity loss and global food security are hence two major challenges of our time. Linking biodiversity and food security issues from a research perspective, and seeking synergies between them is likely to generate multiple benefits for social, ecological and economic development. Follow this link to register, submit your abstract and secure your hotel reservations. Full Article News
syn Biodiversity and Food Security – From Trade-offs to Synergies By www.eubon.eu Published On :: Wed, 28 May 2014 08:57:00 +0300 3rd International Conference on Biodiversity and the UN Millennium Development Goals - October 29-31, 2014, Aix-en-Provence, France This international conference is the third in a series, organized by the French CNRSInstitut Ecologie et Environnement (InEE) and the German Leibniz Association (WGL). The goal is to identify science-based solutions for global sustainability focusing on the issues of biodiversity and food security. Current ecological, economic and societal challenges for development require a holistic understanding of food security and environmental management: from this perspective, biodiversity can be seen as key to overcome trade-offs and to develop synergies between the food system and the conservation of landscapes, ecosystems, and species. The conference seeks to attract scientists from basic and applied research. It involves policy makers and other stakeholders concerned with biodiversity and food security themes who are interested in developing new solutions and strategies. It will connect researchers and stakeholders from natural sciences, social sciences, economics, humanities, technology and related fields. http://biodiv2014.sciencesconf.org/ Full Article Events
syn Biodiversity knowledge synthesis at the European scale: actors and steps By www.eubon.eu Published On :: Wed, 15 Jun 2016 15:57:29 +0300 Full Article Events
syn Learn the Cure for Burned-Out Syndrome By www1.cbn.com Published On :: Wednesday, August 23, 2023 - 12:00pm BURNED OUT Burnout can occur for many reasons, and is common in certain professions, including the military, clergy, and healthcare. As a busy physician with young children, Dr. Saundra Dalton-Smith was a prime candidate. She remembers the day her chaotic life simply stopped her in her tracks: “So I did what any burned-out human would do after picking up the kids from day care. I set them in front of the TV with a snack, and I lay on the floor.” She remained there for quite a while. “The smile... Full Article
syn Computer vision syndrome By www.safetyandhealthmagazine.com Published On :: Mon, 31 Jul 2017 00:00:00 -0400 Computer vision syndrome, also referred to as digital eyestrain, encompasses a group of vision-related problems that result from prolonged computer, tablet, e-reader and smartphone use, according to the American Optometric Association. Full Article
syn Synerion USA Extends Security Market Presence With Qumulex Buy By www.sdmmag.com Published On :: Tue, 08 Oct 2024 09:02:21 -0400 Qumulex is a Fishers, Ind.-based provider of cloud-based video surveillance and access control solutions. Full Article
syn What is hypothenar hammer syndrome? By www.safetyandhealthmagazine.com Published On :: Sun, 25 Apr 2021 00:00:00 -0400 Workers, do you use the edge of the palm of your hand to grind, push or twist hard objects? If you do this often, you’re at risk of hypothenar hammer syndrome – a condition caused when blood flow to the fingers is reduced. Full Article
syn A better understanding of carpal tunnel syndrome By www.safetyandhealthmagazine.com Published On :: Sun, 29 Jan 2017 00:00:00 -0500 What is carpal tunnel syndrome, and where is the carpal tunnel? Mayo Clinic explains: The carpal tunnel is a narrow passageway located on the palm-side of your wrist that “protects a main nerve to your hand and the nine tendons that bend your fingers.” Carpal tunnel syndrome results from compressing this nerve, which produces “numbness, tingling and, eventually, hand weakness.” Full Article
syn A look at Raynaud’s syndrome By www.safetyandhealthmagazine.com Published On :: Sun, 23 Oct 2022 00:00:00 -0400 Raynaud’s phenomenon – sometimes called Raynaud’s syndrome or disease – is a disorder of blood circulation in the fingers and toes (and less commonly in the ears and nose). The cause: Several. Full Article
syn Study Shows Tree Nuts Reduce Metabolic Syndrome Risk in Young Adults By www.preparedfoods.com Published On :: Fri, 15 Dec 2023 05:00:00 -0500 Full Article
syn Florida Food Products: Remove Synthetics By www.preparedfoods.com Published On :: Thu, 12 Jan 2023 12:30:00 -0500 Visitors to booth #BC9419 can sample several prototypes, including a delicious hot dog bite that features FFP’s performance and protection ingredient solutions, showcasing how easily they can achieve a fully clean label with maximum protection, and better texture and flavor. Full Article
syn Echo Antioxidant Water by Synergy Science By www.preparedfoods.com Published On :: Wed, 04 Aug 2021 13:46:21 -0400 Echo Antioxidant Water™ is simply water infused with hydrogen gas. Hydrogen serves as a powerful selective antioxidant. While other sources of antioxidants, like blueberries, may promote healthy oxidation on a low level, hydrogen selectively neutralizes cytotoxic free radicals, helping eliminate oxidative stress and inflammation. Full Article
syn Shaw Sports Turf Named Official Synthetic Turf Provider of the College Football Playoff By www.floortrendsmag.com Published On :: Wed, 08 Nov 2023 18:00:00 -0500 Through this partnership, Shaw Sports Turf will showcase its innovative, differentiated products throughout the event spaces leading up to the 2024 national championship game, slated for January 8, 2023, at Houston’s NRG Stadium. Full Article
syn Synchrony’s Vince Lowe on the Future of the Retail Shopping Experience By www.floortrendsmag.com Published On :: Tue, 29 Oct 2024 10:30:00 -0400 Vince Lowe, senior VP and general manager home specialty and flooring with Synchrony, talks through the high points on“The Future of Retail” report, reveals more about consumer shopping trends, how technology is shaping the shopping experience and where technology is heading in the next six years. Full Article
syn J+J Flooring Launches Synergy, Expands Kinetex Line of Textile Composite Flooring By www.floortrendsmag.com Published On :: Tue, 22 Oct 2024 06:00:00 -0400 The structured pattern in warm and cool neutrals with unique accent colors provides a sophisticated look for workplace, retail, education, multifamily, and healthcare spaces Full Article
syn Syntegon Debuts Vertical Bagger for Coffee By www.foodengineeringmag.com Published On :: Tue, 03 Sep 2024 11:12:34 -0400 The vertical bagger has a compact machine layout for small footprint and good accessibility from all sides. Full Article
syn Evidence-based decision-making in the treatment of speech, language, and communication disorders in Down syndrome; a scoping review By ifp.nyu.edu Published On :: Thu, 31 Oct 2024 02:39:16 +0000 Journal of Intellectual Disabilities, Ahead of Print. This scoping review examined available scientific evidence according to the PRISMA-ScR guideline on the subject of treatment interventions by speech and language therapists of speech, language, and communication needs in people with Down syndrome. A literature search in PubMed, Embase, Cinahl, Cochrane, and Web of Science yielded 41 […] The post Evidence-based decision-making in the treatment of speech, language, and communication disorders in Down syndrome; a scoping review was curated by information for practice. Full Article Meta-analyses - Systematic Reviews
syn Impact of selective reporting bias on stroke trials: potential compromise in evidence synthesis – A cross-sectional study By ifp.nyu.edu Published On :: Mon, 04 Nov 2024 02:21:07 +0000 Accurate reporting of outcomes is crucial for interpreting the results of randomized controlled trials (RCTs). However, selectively reporting outcomes in publications to achieve researchers’ anticipated result… Read the full article › The post Impact of selective reporting bias on stroke trials: potential compromise in evidence synthesis – A cross-sectional study was curated by information for practice. Full Article Open Access Journal Articles
syn Who masterminds the Havana syndrome phenomenon? By english.pravda.ru Published On :: Tue, 26 Oct 2021 21:18:00 +0300 On September 15, 2021, US Defense Secretary Lloyd Austin ordered all military personnel, Defense Department civilian officials and contractors to report any symptoms of Havana syndrome, a mysterious disease that affected US diplomatic missions in many countries around the world. Reference: The mysterious disease manifested itself for the first time in 2016 in Havana, Cuba, where it literally wiped out the staff of the US Embassy. The victims reported that at first they heard strange grinding and ringing sounds, and then they either lost consciousness, or began to experience severe migraines, dizziness and disorientation. The diplomatic mission had to be closed, and the personnel had to be repatriated. At least 59 Americans in Cuba and China have been screened or treated for the unknown illness. The total number of patients amounts to at least 130 people. Full Article Science
syn Alexander Solzhenitsyn, Dostoyevsky of 20th century, dies of heart failure By english.pravda.ru Published On :: Mon, 04 Aug 2008 02:26:02 +0400 Alexander Solzhenitsyn, Dostoyevsky of 20th century, dies of heart failureAlexander Solzhenitsyn died in Moscow at age 89. President Dmitry Medvedev presented his condolences to writer’s wife and sons. Stepan Solzhenitsyn told The Associated Press his father died late Sunday of heart failure, but declined further comment. Solzhenitsyn's unflinching accounts of torment and survival in the Soviet Union's labor camps riveted his countrymen, whose secret history he exposed. They earned him 20 years of bitter exile, but international renown. And they inspired millions, perhaps, with the knowledge that one person's courage and integrity could, in the end, defeat the totalitarian machinery of an empire. Full Article History traditions
syn Formula 1 looks to synthetic fuels as the future, Instead of going electric By english.pravda.ru Published On :: Fri, 03 Mar 2023 17:05:00 +0300 Formula 1 (F1) has been striving to become more environmentally friendly in recent years while still remaining relevant beyond the race track. The series has included more technology that is seen in street cars, such as small-displacement engines with turbos and hybridization. However, F1's CEO, Stefano Domenicali, has said in an interview with an Italian paper that the series will "never go electric." F1 sees synthetic fuels, also known as e-fuels, as the future of the series. These lab-created fuels are already in limited production but come with an extreme cost. However, this is not a problem for motorsport. F1's goal is to have e-fuels powering the grid by 2026 and then working towards finding a way to use them in passenger cars as combustion bans start to take effect in nations in the 2030s, just as F1 hopes to become carbon neutral. Full Article Sport
syn Exploiting fourth-generation synchrotron radiation for enzyme and photoreceptor characterization By journals.iucr.org Published On :: (Time-resolved) macromolecular crystallography at the new ESRF-ID29 beamline is described. Full Article text
syn Synthesis and structural study of the partially disordered complex hexagonal phase δ1-MnZn9.7 By journals.iucr.org Published On :: A detailed structural characterization of the δ1-MnZn9.7 phase is presented. Full Article text
syn Synthesis and structural study of the partially disordered complex hexagonal phase δ1-MnZn9.7 By journals.iucr.org Published On :: 2024-10-02 A detailed structural analysis of the Zn-rich δ1-MnZn9.7 phase using single-crystal X-ray diffraction is presented. The δ1 phase has been synthesized by the high-temperature synthetic route. The structure crystallizes in space group P63/mmc (Pearson symbol hP556) with unit-cell parameters: a = b = 12.9051 (2) Å and c = 57.640 (1) Å. The 556 atoms are distributed over 52 Wyckoff positions in the hexagonal unit cell: seven ordered Mn sites, 37 ordered Zn sites and eight positionally disordered Zn sites. The structure predominantly consists of Frank–Kasper polyhedra (endohedral icosahedra Zn12 and icosioctahedron Zn16) and four distinct types of glue Zn atoms. The structure comprises a 127-atom supercluster (Mn13Zn114), a 38-atom extended Pearce cluster (Mn3Zn35), a 46-atom L-tetrahedron (Mn4Zn42), a Friauf polyhedron (Zn17), a disordered icosahedral cluster (MnZn12) and four glue Zn atoms. Positionally disordered Zn sites around an Mn site can be visualized as the superimposition of three differently oriented Zn12 icosahedra. Full Article text
syn X-ray crystallographic structure of a novel enantiopure chiral isothiourea with potential applications in enantioselective synthesis By journals.iucr.org Published On :: 2024-01-01 The synthesis of a chiral isothiourea, namely, (4aR,8aR)-3-phenyl-4a,5,6,7,8,8a-hexahydrobenzo[4,5]imidazo[2,1-b]thiazol-9-ium bromide, C15H17N2S+·Br−, with potential organocatalytic and anti-inflammatory activity is reported. The preparation of the heterocycle of interest was carried out in two high-yielding steps. The hydrobromide salt of the isothiourea of interest provided suitable crystals for X-ray diffraction analysis, the results of which are reported. Salient observations from this analysis are the near perpendicular arrangement of the phenyl ring and the mean plane of the heterocycle. This conformational characteristic may be relevant with regard the stereoselectivity induced by the chiral isothiourea in asymmetric reactions. Furthermore, evidence was found for the existence of an S...Br− halogen bond. Full Article text
syn Synthesis and crystal structure of Ba2Y0.87(1)Mn1.71(1)Te5 By journals.iucr.org Published On :: 2024-01-01 We report the structural characterization of a new quaternary telluride, Ba2Y0.87(1)Mn1.71(1)Te5, which was synthesized by the direct reaction of the elements inside a vacuum-sealed fused-silica tube. The quaternary phase is the first member of the Ba–M–Mn–Te system (M = Sc and Y). The composition and structure of the phase were elucidated using SEM–EDX (scanning electron microscopy–energy dispersive X-ray spectrometry) and single-crystal X-ray diffraction (SCXRD) studies. The title phase is nonstoichiometric and crystallizes in the monoclinic system (space group C2/m) having the refined unit-cell parameters a = 15.1466 (8), b = 4.5782 (3), c = 10.6060 (7) Å and β = 116.956 (2)°, with two formula units (Z = 2). The pseudo-two-dimensional crystal structure of Ba2Y0.87(1)Mn1.71(1)Te5 consists of distorted YTe6 octahedra and MnTe4 tetrahedra as the building blocks of the structure. The YTe6 octahedra are arranged to form infinite one-dimensional chains by sharing edges along the [010] direction. These chains are further connected to the MnTe4 tetrahedra along the c axis to create layered two-dimensional polyanionic [Y0.87(1)Mn1.71(1)Te5]4− units. The stuffing of Ba2+ cations in between the layers of [Y0.87(1)Mn1.71(1)Te5]4− anions brings the charge neutrality of the structure. Each Ba atom in the structure sits at the centre of a distorted monocapped trigonal prism-like polyhedron of seven Te atoms. Full Article text
syn Room-temperature serial synchrotron crystallography structure of Spinacia oleracea RuBisCO By journals.iucr.org Published On :: 2024-05-29 Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is the enzyme responsible for the first step of carbon dioxide (CO2) fixation in plants, which proceeds via the carboxylation of ribulose 1,5-biphosphate. Because of the enormous importance of this reaction in agriculture and the environment, there is considerable interest in the mechanism of fixation of CO2 by RuBisCO. Here, a serial synchrotron crystallography structure of spinach RuBisCO is reported at 2.3 Å resolution. This structure is consistent with earlier single-crystal X-ray structures of this enzyme and the results are a good starting point for a further push towards time-resolved serial synchrotron crystallography in order to better understand the mechanism of the reaction. Full Article text
syn Crystallographic fragment screen of the c-di-AMP-synthesizing enzyme CdaA from Bacillus subtilis By journals.iucr.org Published On :: 2024-08-23 Crystallographic fragment screening has become a pivotal technique in structure-based drug design, particularly for bacterial targets with a crucial role in infectious disease mechanisms. The enzyme CdaA, which synthesizes an essential second messenger cyclic di-AMP (c-di-AMP) in many pathogenic bacteria, has emerged as a promising candidate for the development of novel antibiotics. To identify crystals suitable for fragment screening, CdaA enzymes from Streptococcus pneumoniae, Bacillus subtilis and Enterococcus faecium were purified and crystallized. Crystals of B. subtilis CdaA, which diffracted to the highest resolution of 1.1 Å, were used to perform the screening of 96 fragments, yielding data sets with resolutions spanning from 1.08 to 1.87 Å. A total of 24 structural hits across eight different sites were identified. Four fragments bind to regions that are highly conserved among pathogenic bacteria, specifically the active site (three fragments) and the dimerization interface (one fragment). The coordinates of the three active-site fragments were used to perform an in silico drug-repurposing screen using the OpenEye suite and the DrugBank database. This screen identified tenofovir, an approved drug, that is predicted to interact with the ATP-binding region of CdaA. Its inhibitory potential against pathogenic E. faecium CdaA has been confirmed by ITC measurements. These findings not only demonstrate the feasibility of this approach for identifying lead compounds for the design of novel antibacterial agents, but also pave the way for further fragment-based lead-optimization efforts targeting CdaA. Full Article text
syn Crystal structure of guanosine 5'-monophosphate synthetase from the thermophilic bacterium Thermus thermophilus HB8 By journals.iucr.org Published On :: 2024-09-18 Guanosine 5'-monophosphate (GMP) synthetase (GuaA) catalyzes the last step of GMP synthesis in the purine nucleotide biosynthetic pathway. This enzyme catalyzes a reaction in which xanthine 5'-monophosphate (XMP) is converted to GMP in the presence of Gln and ATP through an adenyl-XMP intermediate. A structure of an XMP-bound form of GuaA from the domain Bacteria has not yet been determined. In this study, the crystal structure of an XMP-bound form of GuaA from the thermophilic bacterium Thermus thermophilus HB8 (TtGuaA) was determined at a resolution of 2.20 Å and that of an apo form of TtGuaA was determined at 2.10 Å resolution. TtGuaA forms a homodimer, and the monomer is composed of three domains, which is a typical structure for GuaA. Disordered regions in the crystal structure were obtained from the AlphaFold2-predicted model structure, and a model with substrates (Gln, XMP and ATP) was constructed for molecular-dynamics (MD) simulations. The structural fluctuations of the TtGuaA dimer as well as the interactions between the active-site residues were analyzed by MD simulations. Full Article text
syn Sheet-on-sheet fixed target data collection devices for serial crystallography at synchrotron and XFEL sources By journals.iucr.org Published On :: Fixed targets (`chips') offer efficient, high-throughput microcrystal delivery for serial crystallography at synchrotrons and X-ray free-electron lasers (XFELs). Within this family, sheet-on-sheet (SOS) chips offer noteworthy advantages in cost, adaptability, universality and ease of crystal loading. We describe our latest generation of SOS devices, which are now in active use at both synchrotrons and XFELs. Full Article text
syn A micro-beamstop with transmission detection by fluorescence for scanning-beam synchrotron scattering beamlines By journals.iucr.org Published On :: The correct determination of X-ray transmission at X-ray nanoprobes equipped with small beamstops for small- and wide-angle X-ray scattering collection is an unsolved problem with huge implications for data correction pipelines. We present a cost-effective solution to detect the transmission via the X-ray fluorescence of the beamstop with an avalanche photodiode. Full Article text
syn Position-independent product increase rate in a shaker mill revealed by position-resolved in situ synchrotron powder X-ray diffraction By journals.iucr.org Published On :: The position- and time-resolved monitoring of a mechanochemical reaction using synchrotron powder X-ray diffraction revealed a position-independent increase rate of product in the jar of a shaker mill. Full Article text
syn Synthesis and structure of pentakis(2-aminopyridinium) nonavanado(V)tellurate(VI) By journals.iucr.org Published On :: In the title compound, the tellurium(VI) and vanadium(V) atoms are statistically disordered over two of the ten metal-atom sites in the unprotonated [TeV9O28]5– heteropolyanion. Full Article text