Abstract
A simple and robust method for electrochemical alkyl C–H fluorination is presented. Using a simple nitrate additive, a widely available fluorine source (Selectfluor), and carbon-based ...electrodes, a wide variety of activated and unactivated C–H bonds are converted into their C–F congeners. The scalability of the reaction is also demonstrated with a 100 gram preparation of fluorovaline.
Recent studies link increased ozone (O3) and carbon dioxide (CO2) levels to alteration of plant performance and plant-herbivore interactions, but their interactive effects on plant-pollinator ...interactions are little understood. Extra floral nectaries (EFNs) are essential organs used by some plants for stimulating defense against herbivory and for the attraction of insect pollinators, e.g., bees. The factors driving the interactions between bees and plants regarding the visitation of bees to EFNs are poorly understood, especially in the face of global change driven by greenhouse gases. Here, we experimentally tested whether elevated levels of O3 and CO2 individually and interactively alter the emission of Volatile Organic Compound (VOC) profiles in the field bean plant (Vicia faba, L., Fabaceae), EFN nectar production and EFN visitation by the European orchard bee (Osmia cornuta, Latreille, Megachilidae). Our results showed that O3 alone had significant negative effects on the blends of VOCs emitted while the treatment with elevated CO2 alone did not differ from the control. Furthermore, as with O3 alone, the mixture of O3 and CO2 also had a significant difference in the VOCs' profile. O3 exposure was also linked to reduced nectar volume and had a negative impact on EFN visitation by bees. Increased CO2 level, on the other hand, had a positive impact on bee visits. Our results add to the knowledge of the interactive effects of O3 and CO2 on plant volatiles emitted by Vicia faba and bee responses. As greenhouse gas levels continue to rise globally, it is important to take these findings into consideration to better prepare for changes in plant-insect interactions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Inspired by the recent observation of memory effects in the nonlinear optical response of a coherently-driven micro-cavity, we investigate the effects of varying the memory time on the dynamics of ...optical and mechanical resonators. For a memory time that is commensurate with the inverse dissipation rate, both optical and mechanical resonators display stable limit cycles. In this regime, we evidence a cascade of period-doubling bifurcations as the memory time increases. For longer memory times, the mechanical resonator displays a regime of chaotic dynamics associated with a double scroll attractor. We also analyze the effects of the memory time on the spectrum and oscillation amplitude of the oscillator. Our results point to new opportunities for nonlinear energy harvesting, provided that a nonlinearity with memory can be implemented in mechanical systems.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Purpose - This paper investigates the challenges encountered by manufacturing companies in managing sustainability in new product development (NPD). It describes six case studies of manufacturers ...aiming for sustainability improvements but experiencing difficulties in implementing them. Design/methodology/approach - The paper starts with a literature study. Academic literature offers explanations as to why manufacturers want to implement sustainability in NPD, and suggests methods for such implementations. This paper employs the systems theory of control to build a research framework for analyzing the challenges. Empirical data are gathered through workshops and interviews with NPD managers in the case companies. Findings - In-depth analyses have provided three insights. First, the study shows that sustainability pressures and incentives in a firm's contexts can be fuzzy or even absent. The fuzziness of sustainability incentives is often neglected in the literature on sustainability and NPD. Second, the case companies face difficulties when setting the scope, goals, and ambitions that effectively direct NPD decisions and efforts toward designing sustainable products. Third, the results show that deploying sustainability methods, tools, and metrics, such as a life-cycle assessment or design for environment (DfE), are not sufficient to achieve sustainability in NPD. These findings call for research on sustainability and NPD processes in contexts where sustainability incentives and needs are fuzzy so as to acquire insights applicable to sustainable product development management that is proactive rather than reactive. Originality/value - Instead of focusing only on the output of sustainable products, this paper presents a more nuanced perspective on managing sustainability in NPD. Moreover, by adopting the holistic perspective of the systems theory of control, the authors challenge the assumption that there are already sufficient external incentives to force companies toward greater sustainability. Consequently, in the light of proactive sustainability management, the authors recommend three tracks for further research: organization and filtering of information concerning sustainability pressures and incentives in a firm's context; and how to manage sustainability proactively rather than reactively.
Brain-on-a-chip systems are designed to simulate brain activity using traditional in vitro cell culture on an engineered platform. It is a noninvasive tool to screen new drugs, evaluate toxicants, ...and elucidate disease mechanisms. However, successful recapitulation of brain function on these systems is dependent on the complexity of the cell culture. In this study, we increased cellular complexity of traditional (simple) neuronal cultures by co-culturing with astrocytes and oligodendrocyte precursor cells (complex culture). We evaluated and compared neuronal activity (e.g., network formation and maturation), cellular composition in long-term culture, and the transcriptome of the two cultures. Compared to simple cultures, neurons from complex co-cultures exhibited earlier synapse and network development and maturation, which was supported by localized synaptophysin expression, up-regulation of genes involved in mature neuronal processes, and synchronized neural network activity. Also, mature oligodendrocytes and reactive astrocytes were only detected in complex cultures upon transcriptomic analysis of age-matched cultures. Functionally, the GABA antagonist bicuculline had a greater influence on bursting activity in complex versus simple cultures. Collectively, the cellular complexity of brain-on-a-chip systems intrinsically develops cell type-specific phenotypes relevant to the brain while accelerating the maturation of neuronal networks, important features underdeveloped in traditional cultures.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Carbon nanotubes (CNTs) possess many unique electronic and mechanical properties and are thus interesting for numerous novel industrial and biomedical applications. As the level of production and use ...of these materials increases, so too does the potential risk to human health. This study aims to investigate the feasibility and challenges associated with conducting a human health risk assessment for carbon nanotubes based on the open literature, utilising an approach similar to that of a classical regulatory risk assessment. Results indicate that the main risks for humans arise from chronic occupational inhalation, especially during activities involving high CNT release and uncontrolled exposure. It is not yet possible to draw definitive conclusions with regards the potential risk for long, straight multi-walled carbon nanotubes to pose a similar risk as asbestos by inducing mesothelioma. The genotoxic potential of CNTs is currently inconclusive and could be either primary or secondary. Possible systemic effects of CNTs would be either dependent on absorption and distribution of CNTs to sensitive organs or could be induced through the release of inflammatory mediators. In conclusion, gaps in the data set in relation to both exposure and hazard do not allow any definite conclusions suitable for regulatory decision-making. In order to enable a full human health risk assessment, future work should focus on the generation of reliable occupational, environmental and consumer exposure data. Data on toxicokinetics and studies investigating effects of chronic exposure under conditions relevant for human exposure should also be prioritised.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
STUDY QUESTION
Is it feasible to disseminate testicular tissue cryopreservation with a standardized protocol through a coordinated network of centers and provide centralized ...processing/freezing for centers that do not have those capabilities?
SUMMARY ANSWER
Centralized processing and freezing of testicular tissue from multiple sites is feasible and accelerates recruitment, providing the statistical power to make inferences that may inform fertility preservation practice.
WHAT IS KNOWN ALREADY
Several centers in the USA and abroad are preserving testicular biopsies for patients who cannot preserve sperm in anticipation that cell- or tissue-based therapies can be used in the future to generate sperm and offspring.
STUDY DESIGN, SIZE, DURATION
Testicular tissue samples from 189 patients were cryopreserved between January 2011 and November 2018. Medical diagnosis, previous chemotherapy exposure, tissue weight, and presence of germ cells were recorded.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Human testicular tissue samples were obtained from patients undergoing treatments likely to cause infertility. Twenty five percent of the patient’s tissue was donated to research and 75% was stored for patient’s future use. The tissue was weighed, and research tissue was fixed for histological analysis with Periodic acid-Schiff hematoxylin staining and/or immunofluorescence staining for DEAD-box helicase 4, and/or undifferentiated embryonic cell transcription factor 1.
MAIN RESULTS AND THE ROLE OF CHANCE
The average age of fertility preservation patients was 7.9 (SD = 5) years and ranged from 5 months to 34 years. The average amount of tissue collected was 411.3 (SD = 837.3) mg and ranged from 14.4 mg—6880.2 mg. Malignancies (n = 118) were the most common indication for testicular tissue freezing, followed by blood disorders (n = 45) and other conditions (n = 26). Thirty nine percent (n = 74) of patients had initiated their chemotherapy prior to undergoing testicular biopsy. Of the 189 patients recruited to date, 137 have been analyzed for the presence of germ cells and germ cells were confirmed in 132.
LIMITATIONS, REASONS FOR CAUTION
This is a descriptive study of testicular tissues obtained from patients who were at risk of infertility. The function of spermatogonia in those biopsies could not be tested by transplantation due limited sample size.
WIDER IMPLICATIONS OF THE FINDINGS
Patients and/or guardians are willing to pursue an experimental fertility preservation procedure when no alternatives are available. Our coordinated network of centers found that many patients request fertility preservation after initiating gonadotoxic therapies. This study demonstrates that undifferentiated stem and progenitor spermatogonia may be recovered from the testicular tissues of patients who are in the early stages of their treatment and have not yet received an ablative dose of therapy. The function of those spermatogonia was not tested.
STUDY FUNDING/COMPETING INTEREST(S)
Support for the research was from the Eunice Kennedy Shriver National Institute for Child Health and Human Development grants HD061289 and HD092084, the Scaife Foundation, the Richard King Mellon Foundation, the Departments of Ob/Gyn & Reproductive Sciences and Urology of the University of Pittsburgh Medical Center, United States-Israel Binational Science Foundation (BSF), and the Kahn Foundation. The authors declare that they do not have competing financial interests.
The replication of small DNA viruses requires both host DNA replication and repair factors that are often recruited to subnuclear domains termed viral replication centers (VRCs). Aside from serving ...as a spatial focus for viral replication, little is known about these dynamic areas in the nucleus. We investigated the organization and function of VRCs during murine polyomavirus (MuPyV) infection using 3D structured illumination microscopy (3D-SIM). We localized MuPyV replication center components, such as the viral large T-antigen (LT) and the cellular replication protein A (RPA), to spatially distinct subdomains within VRCs. We found that viral DNA (vDNA) trafficked sequentially through these subdomains post-synthesis, suggesting their distinct functional roles in vDNA processing. Additionally, we observed disruption of VRC organization and vDNA trafficking during mutant MuPyV infections or inhibition of DNA synthesis. These results reveal a dynamic organization of VRC components that coordinates virus replication.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The subjective sense of certainty, or confidence, in ambiguous sensory cues can alter the interpretation of reward feedback and facilitate learning. We trained rats to report the orientation of ...ambiguous visual stimuli according to a spatial stimulus-response rule that must be learned. Following choice, rats could wait a self-timed delay for reward or initiate a new trial. Waiting times increase with discrimination accuracy, demonstrating that this measure can be used as a proxy for confidence. Chemogenetic silencing of BLA shortens waiting times overall whereas ACC inhibition renders waiting times insensitive to confidence-modulating attributes of visual stimuli, suggesting contribution of ACC but not BLA to confidence computations. Subsequent reversal learning is enhanced by confidence. Both ACC and BLA inhibition block this enhancement but via differential adjustments in learning strategies and consistent use of learned rules. Altogether, we demonstrate dissociable roles for ACC and BLA in transmitting confidence and learning under uncertainty.
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