The Nascent State Ferreira, Filipe
Philosophies (Basel),
04/2024, Letnik:
9, Številka:
2
Journal Article
Recenzirano
Odprti dostop
I suggest here ecologies of the nascent state, posing the following general questions: what is this state and what is it to live, to fabricate modes of life, in its immanence? I believe populating ...this state is, by right, ‘ecological’, even if what I offer here is only a sketch or glimpse, playful as it is, of the possibility of such modes of life, of dwelling. As I develop it here, the nascent is in flight of being. It is populated by lesser, minoritarian existences. If it is ‘ecological’, it is because these existences, or modes of becoming, are themselves, in their own right, ‘ecologies’, that is, modes of dwelling, of life, on the ‘other side of existence’, as Antonin Artaud put it once, in exile from Being. The power to return eternally to the nascent state is the power to live, to dwell, in the absolute forgetfulness of Being, in the interstice where philosophy supposedly ends, but where it nevertheless begins again, in oblivion itself, where being is never already the verticality of Being, its difference with beings, but always nascent, in the beginning, eternally so.
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•Biomaterials are developed from lightweight and strong nanocellulose gels and foams.•Nanocellulose scaffolds (NCS) are promising analogues to extracellular matrices.•Their biology ...and structure make plant nanomaterials ideal for tissue engineering.•Cell culturing and implantation with NCS are demonstrated in vitro and in vivo.•Next-generation biomaterials can be engineered from nanocelluloses.
We report on the latest scientific advances related to the use of porous foams and gels prepared with cellulose nanofibrils (CNF) and nanocrystals (CNC) as well as bacterial nanocellulose (BNC) – collectively nanocelluloses – as biomedical materials for application in tissue regeneration. Interest in such applications stems from the lightweight and strong structures that can be efficiently produced from these nanocelluloses. Dried nanocellulose foams and gels, including xerogels, cryogels, and aerogels have been synthesized effortlessly using green, scalable, and cost-effective techniques. Methods to control structural features (e.g., porosity, morphology, and mechanical performance) and biological interactions (e.g., biocompatibility and biodegradability) are discussed in light of specific tissues of interest. The state-of-the-art in the field of nanocellulose-based scaffolds for tissue engineering is presented, covering physicochemical and biological properties relevant to these porous systems that promise groundbreaking advances. Specifically, these materials show excellent performance for in vitro cell culturing and in vivo implantation. We report on recent efforts related to BNC scaffolds used in animal and human implants, which furthermore support the viability of CNF- and CNC-based scaffolds in next-generation biomedical materials.
Influenza A virus has an eight-partite RNA genome that during viral assembly forms a complex containing one copy of each RNA. Genome assembly is a selective process driven by RNA-RNA interactions and ...is hypothesized to lead to discrete punctate structures scattered through the cytosol. Here, we show that contrary to the accepted view, formation of these structures precedes RNA-RNA interactions among distinct viral ribonucleoproteins (vRNPs), as they assemble in cells expressing only one vRNP type. We demonstrate that these viral inclusions display characteristics of liquid organelles, segregating from the cytosol without a delimitating membrane, dynamically exchanging material and adapting fast to environmental changes. We provide evidence that viral inclusions develop close to endoplasmic reticulum (ER) exit sites, depend on continuous ER-Golgi vesicular cycling and do not promote escape to interferon response. We propose that viral inclusions segregate vRNPs from the cytosol and facilitate selected RNA-RNA interactions in a liquid environment.
The availability of a reliable and accurate indoor positioning system (IPS) for emergency responders during on-duty missions is regarded as an essential tool to improve situational awareness of both ...the emergency responders and the incident commander. This tool would facilitate the mission planning, coordination, and accomplishment, as well as decrease the number of on-duty deaths. Due to the absence of global positioning system signal in indoor environments, many other signals and sensors have been proposed for indoor usage. However, the challenging scenarios faced by emergency responders imply explicit restrictions and requirements on the design of an IPS, making the use of some technologies, techniques, and methods inadequate on these scenarios. This survey identifies the specific requirements of an IPS for emergency responders and provides a tutorial coverage of the localization techniques and methods, highlighting the pros and cons of their use. Then, the existing IPSs specifically developed for emergency scenarios are reviewed and compared with a focus on the design choices, requirements, and additional features. By doing so, an overview of current IPS schemes as well as their performance is given. Finally, we discuss the main issues of the existing IPSs and some future directions.
A major challenge exists in the preparation of scaffolds for bone regeneration, namely, achieving simultaneously bioactivity, biocompatibility, mechanical performance and simple manufacturing. Here, ...cellulose nanofibrils (CNF) are introduced for the preparation of scaffolds taking advantage of their biocompatibility and ability to form strong 3D porous networks from aqueous suspensions. CNF are made bioactive for bone formation through a simple and scalable strategy that achieves highly interconnected 3D networks. The resultant materials optimally combine morphological and mechanical features and facilitate hydroxyapatite formation while releasing essential ions for
in vivo
bone repair. The porosity and roughness of the scaffolds favor several cell functions while the ions act in the expression of genes associated with cell differentiation. Ion release is found critical to enhance the production of the bone morphogenetic protein 2 (BMP-2) from cells within the fractured area, thus accelerating the
in vivo
bone repair. Systemic biocompatibility indicates no negative effects on vital organs such as the liver and kidneys. The results pave the way towards a facile preparation of advanced, high performance CNF-based scaffolds for bone tissue engineering.
Cellulose nanofibrils and bioactive glass are assembled into a porous network and used as scaffold for bone regeneration. The obtained organic-inorganic composite material optimally combine the necessary features for
in vivo
bone repair.
The interaction of low‐energy electrons with biomolecules plays an important role in the radiation‐induced alteration of biological tissue at the molecular level. At electron energies below 15 eV, ...dissociative electron attachment is one of the most important processes in terms of the chemical transformation of molecules. So far, a common approach to study processes at the molecular level has been to carry out investigations with single biomolecular building blocks like pyrimidine as model molecules. Electron attachment to single pyrimidine, as well as to pure clusters and hydrated clusters, was investigated in this study. In striking contrast to the situation with isolated molecules and hydrated clusters, where no anionic monomer is detectable, we were able to observe the molecular anion for the pure clusters. Furthermore, there is evidence that solvation effectively prevents the ring fragmentation of pyrimidine after electron capture.
Low‐energy electrons lead to efficient decomposition of single biomolecules in the gas phase. The situation radically changes when the molecules are solvated. Pure and hydrated clusters of pyrimidine were formed and exposed to low‐energy electrons. The monomer anion of pyrimidine can be stabilized only in the case of pure pyrimidine clusters and when the anion is first electronically excited.
Part of the energy deposited in biological tissue by high-energy radiation is converted to secondary electrons. The knowledge at the molecular level on radiation interaction with biological species ...has increased due to the contributions of many different scientists working on radiation physics and radiation chemistry. The intention of this Special Issue on electron and photon interactions with (bio) molecules is to bring together different areas of knowledge that focus on radiation interactions with matter.
We introduce a new drift model for slow environmental perturbation affecting modal coupling in optical multi-mode fibers. This model preserves the mode coupling strength asymmetries characteristic to ...mode pairs of different mode groups while decorrelating the fiber transmission matrix. Existing drift models were derived for the strong coupling regime, in which case the coupling matrix elements are identically distributed, and not suitable for the weak to intermediate coupling regime as shown here. The models' impact on the inherent crosstalk characteristic of a fiber were evaluated for all linear coupling regimes and for fibers with up to 42 spatial and polarization modes. Moreover, transmission performance of 32 GBd 16-QAM (per polarization mode) over the dynamic channel is studied considering singular value decomposition (SVD) pre-coding for the multiple-input multiple-output multi-mode fiber channel. The impact of slow drift on channel equalization performance is evaluated in terms of residual crosstalk. A large discrepancy is observed for fiber channels in the weak and intermediate coupling regimes, while converging in the strong coupling regime. Furthermore, we show that 2 × 1 multiple-input single-output equalizers can be sufficient to compensate for the residual crosstalk in the weak to intermediate linear coupling regime and achieve optimal performance.
We investigate transceiver design and digital signal processing for spatially multiplexed transmission over multimode fibers. In conventional architectures, the full spatial domain of the ...transmission fiber has to be detected and processed such that the modal walk-off and mixture can be estimated and equalized. These architectures scale poorly with the number of modes supported, besides the sparsity of the fiber transfer matrix is not fully exploited. Instead, here we aim to employ selective mode vector launch and detection in order to minimize the number of optical front-ends required. In this case, an ideal basis for multiplexing is offered by principal modes, that to first order are frequency independent. We show that such mode vector basis can be used for full baud rate transmission over inter-data center distances despite limited coherence bandwidth and vulnerability to environmental-induced drift of the optical channel. It is shown that crosstalk at the receiver front-end can be significantly suppressed, critically reducing the number of coherent receiver front-ends to that of spatial tributaries aimed for data transmission - as opposed to the total number of fiber modes. Residual crosstalk can still be experienced due to environmental-induced channel drift and loss of orthogonality in presence of mode dependent loss. Multiple-input single-output digital signal processing is shown to be effective in this case, with the required equalizer array size scaling sub-linearly with the number of tributaries. A multimode fiber with 156 spatial and polarization modes and optimized for low modal dispersion is considered.
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