59 research outputs found
Transgender Day of Visibility 2022 : an interview with Adam Armada-Moreira and Ave Bisesi on trans experiences in STEM
No full textThis year at Communications Biology, we wanted to celebrate Transgender Day of Visibility by highlighting researchers at multiple career stages. In this Q&A, we asked early-career biologists about their own achievements, academic experiences, and how STEM can better support trans researchers
Manganese dioxide nanosheet-containing reactors as antioxidant support for neuroblastoma cells
No full textSupporting mammalian cells against reactive oxygen species such as hydrogen peroxide (H2O2) is essential. Bottom-up synthetic biology aims to integrate designed artificial units with mammalian cells. Here, we used manganese dioxide nanosheets (MnO2-NSs) as catalytically active entities that have superoxide dismutase-like and catalase-like activities. The integration of these MnO2-NSs into 7 mu m reactors was able to assist SH-SY5Y neuroblastoma cells when stressed with H2O2. Complementary, Janus-shaped 800 nm reactors with one hemisphere coated with MnO2-NSs showed directed locomotion in cell media with top speeds up to 50 mu m s(-1) when exposed to 300 mM H2O2 as a fuel, while reactors homogeneously coated with MnO2-NSs were not able to outperform Brownian motion. These Janus-shaped reactors were able to remove H2O2 from the media, protecting cells cultured in the proximity. This effort advanced the use of bottom-up synthetic biology concepts in neuroscience
Plant electrophysiology with conformable organic electronics: Deciphering the propagation of Venus flytrap action potentials
No full textElectrical signals in plants are mediators of long-distance signaling and correlate with plant movements and responses to stress. These signals are studied with single surface electrodes that cannot resolve signal propagation and integration, thus impeding their decoding and link to function. Here, we developed a conformable multielectrode array based on organic electronics for large-scale and high-resolution plant electrophysiology. We performed precise spatiotemporal mapping of the action potential (AP) in Venus flytrap and found that the AP actively propagates through the tissue with constant speed and without strong directionality. We also found that spontaneously generated APs can originate from unstimulated hairs and that they correlate with trap movement. Last, we demonstrate that the Venus flytrap circuitry can be activated by cells other than the sensory hairs. Our work reveals key properties of the AP and establishes the capacity of organic bioelectronics for resolving electrical signaling in plants contributing to the mechanistic understanding of long-distance responses in plants
Manganese oxide nanoflowers and liposome encapsulated superoxide dismutase microreactors on preventing oxidative stress
No full textRESUMO: O cérebro é particularmente vulnerável ao stress oxidativo, uma vez que tem
um elevado consumo de oxigénio que leva à produção de espécies reativas de
oxigénio (ERO) e, simultaneamente, expressa uma baixa quantidade de enzimas
antioxidantes. Enquanto a maioria dos tratamentos para o stress oxidativo se focam
na eliminação das ERO, o mimetismo celular, que inclui reatores que podem
incorporar várias entidades ativas, é considerado um novo modelo de tratamento
eficiente e durador. Por exemplo, o consumo de ERO produzidas em excesso pode ser
alcançado através da utilização da enzima superóxido dismutase (SOD) e de
nanoflores de óxido de manganês.
Este trabalho teve como objetivo o desenvolvimento de microreatores com
capacidade de mimetizar as características celulares antioxidantes, de modo a
prevenir o stress oxidativo induzido por H2O2 e lipopolisacárido (LPS) na linha celular
SH-SY5Y de neuroblastoma humano e em culturas primárias mistas, respetivamente.
SOD encapsulado em lipossomas (LSOD) e nanoflores foram sintetizados e caracterizados
física- e cataliticamente. Microreatores foram construídos a partir dum núcleo de
poliestireno, incorporando nanoflores ou nanoflores+LSOD como entidades ativas, e com
deposição electroestática de camadas intermédias de polidopamina e poli-L-lisina.
Quer as nanoflores, quer os microreatores, demonstraram atividade de SOD e
catalase. O LSOD mostrou atividade baixa de SOD, que foi anulada pela incorporação
destes no microreactor. Enquanto as nanoflores livres mostraram altas taxas de
toxicidade na linha celular SH-SY5Y, quando incorporadas nos microreactores, estes
mostraram baixos níveis de toxicidade direta e inibição de proliferação na linha
celular. Os microreactores foram capazes de reverter parcialmente a viabilidade da
linha celular tratada com H2O2, no entanto induziram um aumento nos níveis de ERO
intracelulares nas culturas primarias, representativo de um efeito dual.
Globalmente, microreatores demonstraram a capacidade de proteção
antioxidante às células, oferecendo uma alternativa aos habituais agentes terapêuticos e
representando um suporte enzimático para as células biológicas.
Palavras-chave: stress oxidativo; mimetização celular; nanoflores de oxido de manganês;
microreator.ABSTRACT: The lack of antioxidant defences and high oxygen consumption rates render the
brain vulnerable to oxidative stress. While most treatments target the scavenging of
reactive oxygen species (ROS), cell mimicry does so by offering a long-term antioxidant
support to protect the brain cell population from oxidative damage. Layer-by-layer
microreactor assembling technique allows the development of personalized therapeutic
particles, incorporating various active principles into targeting pertinent issues. For
instance, catalytic activity can be achieved by superoxide dismutase (SOD) or manganese
oxide (Mn3O4) nanoflowers. Incorporation of liposome-encapsulated enzyme SOD (LSOD)
and/or nanoflowers in microreactors allows drawing a line between natural and artificial
catalytic entities in cell mimicry.
Thus, this work aimed to expand the use of microreactors to support
neuroblastoma cells and mixed primary cultures against H2O2- and lipopolysaccharide
(LPS) both physically and enzymatically. Microreactors were assembled with a
polystyrene core, following by the deposition of polydopamine and poly-L-lysine
precursor layers before immobilizing only nanoflowers or nanoflowers+LSOD as
intermediate layers.
Synthesized nanoflowers and microreactors showed both SOD and catalase
activity, while LSOD retained low activity that was abolished by microreactor assembly, and
therefore considered redundant for posterior use. While nanoflowers showed significant
toxicity at low concentrations when incubated with cells, microreactors with integrated
nanoflowers caused an inhibition of cell proliferation and only minor toxicity at high
concentrations. Importantly, cells in the presence of the microreactors showed higher
viability when subjected to H2O2, illustrating their capacity to rescue cells from oxidative
stress induced death. Primary cultures showed consistence with the previous toxicity
results but also a rise in intracellular ROS, reflective of possible underlying nanoflower
effect.
Taken together, microreactors with dual catalytic activity are a cell mimicry approach that
can assist their mammalian counterpart to survive changes in their environment
The role of glutamate receptors and transporters in epilepsy: evidence from animal studies
No full text: Epilepsy encompasses a group of chronic brain disorders characterized by recurrent, hypersynchronous activity of neuronal clusters, with epileptic seizures being the primary manifestation of these disorders. The objective of epilepsy treatment is to prevent seizures with minimum adverse side effects. However, approximately 30 % of patients do not respond to available medications. One proposed mechanism of epileptogenesis is glutamate excitotoxicity. When released in excess or not appropriately removed from the synaptic cleft, glutamate hyperactivates receptors, causing a biochemical cascade, which culminates in seizures and cell death. The use of animal models is essential for uncovering potential epileptogenic pathways, understanding the role of receptors and transporters in excitotoxicity, and screening effective antiepileptic treatments. This review examines studies that investigate the role of glutamate transporters and receptors in excitotoxicity and epileptogenesis using animal models. For this, we searched through both PubMed/Medline and ScienceDirect databases. After applying the inclusion and exclusion criteria, 26 (twenty-six) studies were selected for analysis. The studies addressed key glutamate transporter family of excitatory amino acid transporters (EAATs) EAAT1, EAAT2, and EAAT3, responsible for glutamate clearance, as well as AMPA receptor subunits GluA1 and GluA2, NMDA receptor subunits GluN1, GluN2a, and GluN2b, and the metabotropic receptors mGluR5 and mGluR2/3. Results showed that the dysregulation of these transporters and receptors is associated to seizure induction and excitotoxic damage, pointing to their fundamental role in the mechanisms of excitotoxicity and epileptogenesis. These findings highlight the potential of targeting glutamate transporters and receptors to stabilize glutamate homeostasis as an intervention in epilepsy management
Cooperative checkpointing for supercomputing systems
No full textThesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 91-94).A system-level checkpointing mechanism, with global knowledge of the state and health of the machine, can improve performance and reliability by dynamically deciding when to skip checkpoint requests made by applications. This thesis presents such a technique, called cooperative checkpointing, and models its behavior as an online algorithm. Where C is the checkpoint overhead and I is the request interval, a worst-case analysis proves a lower bound of (2 + [C/I])-competitiveness for deterministic cooperative checkpointing algorithms, and proves that a number of simple algorithms meet this bound. Using an expected-case analysis, this thesis proves that an optimal periodic checkpointing algorithm that assumes an exponential failure distribution may be arbitrarily bad relative to an optimal cooperative checkpointing algorithm that permits a general failure distribution. Calculations suggest that, under realistic conditions, an application using cooperative checkpointing may make progress 4 times faster than one using periodic checkpointing. Finally, the thesis suggests an embodiment of cooperative checkpointing for a large-scale high performance computer system and presents the results of some preliminary simulations. These results show that, in extreme cases, cooperative checkpointing improved system utilization by more than 25%, reduced bounded slowdown by a factor of 9, while simultaneously reducing the amount of work lost due to failures by 30%. This thesis contributes a unique approach to providing large-scale system reliability through cooperative checkpointing, techniques for analyzing the approach, and blueprints for implementing it in practice.by Adam Jamison Oliner.M.Eng
Plant Bioelectronics and Biohybrids : The Growing Contribution of Organic Electronic and Carbon-Based Materials
No full textLife in our planet is highly dependent on plants as they are the primary source of food, regulators of the atmosphere, and providers of a variety of materials. In this work, we review the progress on bioelectronic devices for plants and biohybrid systems based on plants, therefore discussing advancements that view plants either from a biological or a technological perspective, respectively. We give an overview on wearable and implantable bioelectronic devices for monitoring and modulating plant physiology that can be used as tools in basic plant science or find application in agriculture. Furthermore, we discuss plant wearable devices for monitoring a plants microenvironment that will enable optimization of growth conditions. The review then covers plant biohybrid systems where plants are an integral part of devices or are converted to devices upon functionalization with smart materials, including self-organized electronics, plant nanobionics, and energy applications. The review focuses on advancements based on organic electronic and carbon-based materials and discusses opportunities, challenges, as well as future steps.Funding Agencies|European UnionEuropean Commission [800926]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR-2017-04910]; Swedish Foundation For Strategic ResearchSwedish Foundation for Strategic Research [FFL18-0101]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Wallenberg Wood Science Center; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]</p
The AWAKE Run 2 programme and beyond
No full textAutores: Edda Gschwendtner, Konstantin Lotov, Patric Muggli, Matthew Wing, Riccardo Agnello, Claudia Christina Ahdida, Maria Carolina Amoedo Goncalves, Yanis Andrebe, Oznur Apsimon, Robert Apsimon, Jordan Matias Arnesano, Anna-Maria Bachmann, Diego Barrientos, Fabian Batsch, Vittorio Bencini, Michele Bergamaschi, Patrick Blanchard, Philip Nicholas Burrows, Birger Buttenschön, Allen Caldwell, James Chappell, Eric Chevallay, Moses Chung, David Andrew Cooke, Heiko Damerau, Can Davut, Gabor Demeter, Amos Christopher Dexter, Steffen Doebert, Francesa Ann Elverson, John Farmer, Ambrogio Fasoli, Valentin Fedosseev, Ricardo Fonseca, Ivo Furno, Spencer Gessner, Aleksandr Gorn, Eduardo Granados, Marcel Granetzny, Tim Graubner, Olaf Grulke, Eloise Daria Guran, Vasyl Hafych, Anthony Hartin, James Henderson, Mathias Hüther, Miklos Kedves, Fearghus Keeble, Vadim Khudiakov, Seong-Yeol Kim, Florian Kraus, Michel Krupa, Thibaut Lefevre, Linbo Liang, Shengli Liu, Nelson Lopes, Miguel Martinez Calderon, Stefano Mazzoni, David Medina Godoy, Joshua Moody, Kookjin Moon, Pablo Israel Morales Guzmán, Mariana Moreira, Tatiana Nechaeva, Elzbieta Nowak, Collette Pakuza, Harsha Panuganti, Ans Pardons, Kevin Pepitone, Aravinda Perera, Jan Pucek, Alexander Pukhov, Rebecca Louise Ramjiawan, Stephane Rey, Adam Scaachi, Oliver Schmitz, Eugenio Senes, Fernando Silva, Luis Silva, Christine Stollberg, Alban Sublet, Catherine Swain, Athanasios Topaloudis, Nuno Torrado, Petr Tuev, Marlene Turner, Francesco Velotti, Livio Verra, Victor Verzilov, Jorge Vieira, Helmut Vincke, Martin Weidl, Carsten Welsch, Manfred Wendt, Peerawan Wiwattananon, Joseph Wolfenden, Benjamin Woolley, Samuel Wyler, Guoxing Xia, Vlada Yarygova, Michael Zepp, Giovanni Zevi Della Porta. ::: Publisher: [MDPI] ::: Location: [
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