4,271 research outputs found
Exploring the role of nanocellulose as potential sustainable material for enhanced oil recovery:New paradigm for a circular economy
Presently, due to growing global energy demand and depletion of existing oil reservoirs, oil industry is focussing on development of novel and effective ways to enhance crude oil recovery and exploration of new oil reserves, which are typically found in challenging environment and require deep drilling in high temperature and high-pressure regime. The nanocelluloses with numerous advantages such as high temperature and pressure stability, ecofriendly nature, excellent rheology modifying ability, interfacial tension reduction capability, etc., have shown a huge potential in oil recovery over conventional chemicals and macro/micro sized biopolymers-based approach. In present review, an attempt has been made to thoroughly investigate the potential of nanocellulose (cellulose nanocrystals/nanofibers) in development of drilling fluid and in enhancement of oil recovery. The impact of various factors such as nanocellulose shape, charge density, inter-particle or inter-fibers interactions after surface functionalization, rheometer geometries, additives, post processing techniques, etc., which provides insight into the attributes of nanocellulose suspension and exemplify their behaviour during oil recovery have also been reviewed and discussed. Finally, the conclusion and challenges in utility of nanocellulose for oilfield applications are addressed. Knowing how to adjust/quantify nanocrystals/nanofibers shape and size; and monitor their interactions might promote their utility in oilfield industry.</p
Neuromodulatory effects on early visual signal processing
Understanding how the brain processes information and generates simple to complex behavior constitutes one of the core objectives in systems neuroscience. However, when studying different neural circuits, their dynamics and interactions researchers often assume fixed connectivity, overlooking a crucial factor - the effect of neuromodulators. Neuromodulators can modulate circuit activity depending on several aspects, such as different brain states or sensory contexts. Therefore, considering the modulatory effects of neuromodulators on the functionality of neural circuits is an indispensable step towards a more complete picture of the brainâs ability to process information. Generally, this issue affects all neural systems; hence this thesis tries to address this with an experimental and computational approach to resolve neuromodulatory effects on cell type-level in a well-define system, the mouse retina. In the first study, we established and applied a machine-learning-based classification algorithm to identify individual functional retinal ganglion cell types, which enabled detailed cell type-resolved analyses. We applied the classifier to newly acquired data of light-evoked retinal ganglion cell responses and successfully identified their functional types. Here, the cell type-resolved analysis revealed that a particular principle of efficient coding applies to all types in a similar way. In a second study, we focused on the issue of inter-experimental variability that can occur during the process of pooling datasets. As a result, further downstream analyses may be complicated by the subtle variations between the individual datasets. To tackle this, we proposed a theoretical framework based on an adversarial autoencoder with the objective to remove inter-experimental variability from the pooled dataset, while preserving the underlying biological signal of interest. In the last study of this thesis, we investigated the functional effects of the neuromodulator nitric oxide on the retinal output signal. To this end, we used our previously developed retinal ganglion cell type classifier to unravel type-specific effects and established a paired recording protocol to account for type-specific time-dependent effects. We found that certain
retinal ganglion cell types showed adaptational type-specific changes and that nitric oxide had a distinct modulation of a particular group of retinal ganglion cells.
In summary, I first present several experimental and computational methods that allow to
study functional neuromodulatory effects on the retinal output signal in a cell type-resolved manner and, second, use these tools to demonstrate their feasibility to study the neuromodulator nitric oxide
Computational methods for biofabrication in tissue engineering and regenerative medicine - a literature review
This literature review rigorously examines the growing scientific interest in computational methods for
Tissue Engineering and Regenerative Medicine biofabrication, a leading-edge area in biomedical innovation, emphasizing the need for accurate, multi-stage, and multi-component biofabrication process models. The paper presents a comprehensive bibliometric and contextual analysis, followed by a literature review, to shed light on the vast potential of computational methods in this domain. It reveals that most existing methods focus on single biofabrication process stages and components, and there is a significant gap in approaches that utilize accurate models encompassing both biological and technological aspects. This analysis underscores the indispensable role of these methods in understanding and effectively manipulating complex biological systems and the necessity for developing computational methods that span multiple stages and components. The review concludes that such comprehensive computational methods are essential for developing innovative and efficient Tissue Engineering and Regenerative Medicine biofabrication solutions, driving forward advancements in this dynamic and evolving field
Sourceâbased morphometry reveals structural brain pattern abnormalities in 22q11.2 deletion syndrome
22q11.2 deletion syndrome (22q11DS) is the most frequently occurring microdeletion in humans. It is associated with a significant impact on brain structure, including prominent reductions in gray matter volume (GMV), and neuropsychiatric manifestations, including cognitive impairment and psychosis. It is unclear whether GMV alterations in 22q11DS occur according to distinct structural patterns. Then, 783 participants (470 with 22q11DS: 51% females, mean age [SD] 18.2 [9.2]; and 313 typically developing [TD] controls: 46% females, mean age 18.0 [8.6]) from 13 datasets were included in the present study. We segmented structural T1âweighted brain MRI scans and extracted GMV images, which were then utilized in a novel sourceâbased morphometry (SBM) pipeline (SSâDetect) to generate structural brain patterns (SBPs) that capture coâvarying GMV. We investigated the impact of the 22q11.2 deletion, deletion size, intelligence quotient, and psychosis on the SBPs. Seventeen GMVâSBPs were derived, which provided spatial patterns of GMV covariance associated with a quantitative metric (i.e., loading score) for analysis. Patterns of topographically widespread differences in GMV covariance, including the cerebellum, discriminated individuals with 22q11DS from healthy controls. The spatial extents of the SBPs that revealed disparities between individuals with 22q11DS and controls were consistent with the findings of the univariate voxelâbased morphometry analysis. Larger deletion size was associated with significantly lower GMV in frontal and occipital SBPs; however, history of psychosis did not show a strong relationship with these covariance patterns. 22q11DS is associated with distinct structural abnormalities captured by topographical GMV covariance patterns that include the cerebellum. Findings indicate that structural anomalies in 22q11DS manifest in a nonrandom manner and in distinct covarying anatomical patterns, rather than a diffuse global process. These SBP abnormalities converge with previously reported cortical surface area abnormalities, suggesting disturbances of early neurodevelopment as the most likely underlying mechanism
Cellular and molecular mechanisms of inflammatory arthritis and fibromyalgia
In Study I, we examined the impact of the hR100E-NGF mutation on inflammatory
pain and bone erosion in both female and male mice. Our findings indicate that
the hR100E-NGF mutation did not affect the development of the peripheral
sensory nervous system at the lumbar DRG, sciatic nerve, ankle joint, or glabrous
skin. Moreover, hR100E-NGF mice displayed sensory thresholds similar to those
of the hWT-NGF mice in response to mechanical, heat, or cold stimulation under
normal conditions. The hR100E-NGF and hWT-NGF mice developed comparable
mechanical and heat sensitivity impairments after the intra-articular injection of
complete Freundâs adjuvant. Notably, the hR100E-NGF mice were insensitive to
nociceptive stimulation in the deeper tissues assessed by weight bearing and gait
analysis. Furthermore, mRNA analysis from the inflamed joint showed a differential
sex-dependent gene expression profile between hR100E-NGF female and male
mice. Finally, the hR100E-NGF female but not the male mice were protected
against the CFA-bone erosion. These data collectively demonstrate that the
R100E NGF mutation effectively protects against joint pain-like behaviors in both
male and female mice while providing bone protection exclusively to female mice
in a monoarthritis model. We propose that manipulating the signaling of NGF and
its receptors in a manner similar to the R100E mutation could be a promising
approach to treating chronic pain and maintaining bone health, particularly in
women.
Study II investigated the effects of injecting purified IgG from fibromyalgia (FM)
patients and healthy controls (HC) in mice. We found that the injection of FM IgG
but not IgG from healthy controls (HC) induces pressure, mechanical, and cold
hypersensitivity in mice that were coupled to enhanced nociceptor
responsiveness to mechanical and cold stimulation. The FM IgG-injected mice
also developed impaired muscular strength and decreased locomotor activity.
Moreover, FM IgG bound and stimulated satellite glial cells (SGCs) in vivo and in
vitro. No FM or HC IgG accumulation was found in the brain or spinal cord of the
injected mice. Our study also demonstrated that FM IgG can bind to satellite glial
cells and neurons in the human DRG. In addition, we observed a significant
reduction in the intraepidermal nerve fiber density in the mice 14 days after the
FM IgG injection. Our results suggest that transferring FM IgG into mice can
replicate some peripheral FM symptoms. This study can provide a valuable animal
model for studying the peripheral physiology of FM. Our discovery could
significantly advance the understanding and treatment of fibromyalgia and other
related conditions. However, more research is needed to understand the cellular
and molecular mechanisms involved in FM-IgG-mediated changes in mice.
Study III aimed to investigate the frequency of anti-satellite glial cell (SGC)
antibodies and the antibody association with the disease severity in FM patients.
We used serum (Karolinska Institutet, Sweden; n=30/group) and plasma (McGill
University, Canada; n=35/group) samples collected from FM patients and HCs. Our
results showed a higher binding intensity of the FM IgG to SGC in vitro.
Furthermore, the frequency of SGC bound to FM IgG was significantly higher than
HC IgG-treated cells. These findings correlated with pain intensity and
fibromyalgia impact questionnaire scores (FIQ, questionnaire was only assessed
in the Karolinska cohort). Further cluster analysis separated the FM group into
severe and mild groups. Additionally, we found that serum from FM patients
contains IgG that binds in greater proportion to SGC in the human DRG, measured
by higher signal intensity. There were no differences in the binding intensity to
neuronal cell bodies or axons between FM and HC serum samples. Finally, the
previous results were confirmed using an FM serum sample with high levels of
anti-SGC antibodies in 5 more human DRGs. To summarize, our report indicates
that levels of anti-human SGC and anti-mouse SGC antibodies are elevated in
patients with FM, which are linked to a more severe form of the disease. Patient
stratification based on their profile of anti-SGC antibodies might benefit from
therapies aiming to decrease circulating IgG or prevent IgG binding. Our results
point to the possible involvement of anti-SGC antibodies and SGCs in the severity
of FM; however, more in-depth studies are necessary to elucidate the antigen or
antigens expressed in the SGC that bind to the circulating anti-SGC antibodies.
In Study IV, we aimed to explore the neuroimmune signature of the FM skin. We
processed 16 FM and 16 HC sex-matched skin biopsies by immunohistochemistry.
Using a pan-neuronal marker, we found lower intraepidermal nerve fiber density
(IENFD) in the FM compared with HC skin. Moreover, the length and volume of
dermal NF200+ nerve profiles were significantly elevated, but we found no
changes in the length of dermal or epidermal Gap43+ nerve profiles in the FM
group. Similarly, we found no changes in the total volume of CD31+ blood vessels
between FM and HC skin. Our results showed that the density of non-nerve
associated S100b+, CD68+, and CD163+ cells was significantly lower in the FM skin.
Furthermore, the dermal CD117+FcERI+ mast cells in the dermis of FM patients were
significantly increased compared with the HCs. Additionally, we found similar
densities of CD207+, CD3+, or Neutrophil elastase+ cells between FM and HC skin
biopsies. mRNA analysis of FM skin showed no changes in Cd68, Cd163, Cx3cr1, or
FceR1 mRNA levels between FM and HC skin. In summary, this study reveals crucial
dermal and epidermal changes in FM skin, particularly regarding nerve fibers and
certain immune cell populations. These findings are highly relevant as they provide
deeper insights into the complex interactions between the nervous and immune
systems in FM. Understanding these changes could be key to developing more
effective treatments for FM, focusing on both the neuropathic and immune
components of the disease
Development of hydrogel cavities of tuneable stiffness for the growth of epithelial crypts
Treballs Finals de Grau d'Enginyeria BiomĂšdica. Facultat de Medicina i CiĂšncies de la Salut. Universitat de Barcelona. Curs: 2023-2024. Tutor/Director: Jordi Comelles PujadasDepending on their function, the epithelial cell monolayers that line the inner surfaces of organs
adopt a variety of three-dimensional shapes. Traditional studies in vitro have been using mainly flat
cell culture dishes, overseeing the impact of these in vivo shapes in tissue function. Recent
research has begun to address this issue, by trying to mimic the 3D structures found in tissues.
However, those novel culture platforms still have some limitations, especially in cases where the
architecture must correspond with the original tissueâs stiffness. Tissues have a quite low
physiological rigidity, and most of the microfabrication techniques used nowadays need quite firm
materials to achieve the desired 3D structures without issue. A type of structure difficult to fabricate
using soft materials are invaginations, which can be found in vivo in kidneys, lungs, and the small
intestine. Low rigidity substrates are typically characterized by high deformability and lack of
structural support, which can result in unprecise final features due to distortions of the material
during the microfabricating process.
In this project, 3D cavities have been fabricated into polyacrylamide (PA), a material which allows
the tuneability of its rigidity by changing the proportion of acrylamides during the synthesis of the
prepolymer solution. Replica moulding has been employed to acquire these structures. The
invaginations successfully recreated key aspects of the in vivo environment, both with their shape
and stiffness, and multiple copies were created easily, enabling precise characterization. Finally,
after the assessment of the mechanical properties and the architectural features of the
microcavities, the functionalization of the samples was successful, confirming the suitability of the
resulting scaffold as a model to study epithelial growth, morphology, and conformity in these inward
bended structures
Bioceramic micro-fillers reinforce antibiofilm and remineralization properties of clear aligner attachment materials
Introduction: Clear aligners, while offering a more hygienic alternative to fixed appliances, are still associated with challenges including plaque accumulation and enamel demineralization. The aim of the present study was to investigate the antibiofilm and remineralization effectiveness of innovative flowable composite attachments containing bioceramic micro-fillers.Methods: Four experimental attachments were formulated and bonded to human enamel specimens: 3M Filtek Supreme flowable composite (Filtek SF) + 10% bioactive glass 45S5 (BAG), Filtek SF + 30% BAG, Filtek SF + 10% Bredigite (BRT), Filtek SF + 30% BRT. Plaque biofilms were grown on the bonded enamel using a standardized protocol and the biofilm-killing effect was assessed by confocal laser scanning microscopy and scanning electron microscopy. Vickers microhardness was measured to evaluate the remineralization effect of the attachments containing bioceramic fillers after acid challenge. Shear bond test was performed to assess the bonding strength.Results: Attachments with bioceramic fillers significantly inhibited plaque biofilm growth in 3 weeks on enamel, contributing over 20% bacterial cell killing in 10% filler groups and over 30% killing in 30% filler groups. All four experimental groups demonstrated significantly higher microhardness values than the control group without fillers on the attachment side. The shear bonding strength was not compromised in the attachments with micro-fillers.Discussion: Proper incorporation of bioceramic micro-fillers in attachments provides an innovative approach for clear aligner therapy with reinforced antibiofilm and remineralization effects without weakening shear bonding strength
CANCER TREATMENT BY TARGETING HDAC4 TRANSLOCATION INDUCED BY MICROSECOND PULSED ELECTRIC FIELD EXPOSURE: MECHANISTIC INSIGHTS THROUGH KINASES AND PHOSPHATASES
Epigenetic modifications, arising from sub-cellular shifts in histone deacetylase (HDAC) activity and localization, present promising strategies for diverse cancer treatments. HDACs, enzymes responsible for post-translational histone modifications, induce these epigenetic changes by removing acetyl groups from Δ-N-acetyl-lysine residues on histones, thereby suppressing gene transcription. Within the HDAC group, class IIa HDACs are notable for their responsiveness to extracellular signals, bridging the gap between external stimuli, plasma membrane, and genome through nuclear-cytoplasmic translocation. This localization offers two significant mechanisms for cancer treatment: nuclear accumulation of HDACs represses oncogenic transcription factors, such as myocyte-specific enhancer factor 2C (MEF2C), triggering various cell death pathways. Conversely, cytoplasmic HDAC accumulation acts similarly to HDAC inhibitors by silencing genes. My dissertation introduces an innovative approach for glioblastoma and breast cancer treatment by investigating the application of microsecond pulsed electric fields. It particularly focuses on HDAC4, a class IIa HDAC overexpressed in these cancers. Beyond demonstrating HDAC4 translocation, my research delves into the intricate roles of kinases and phosphatases, shedding light on the underlying factors governing HDAC4 translocation
Multidisciplinary perspectives on Artificial Intelligence and the law
This open access book presents an interdisciplinary, multi-authored, edited collection of chapters on Artificial Intelligence (âAIâ) and the Law. AI technology has come to play a central role in the modern data economy. Through a combination of increased computing power, the growing availability of data and the advancement of algorithms, AI has now become an umbrella term for some of the most transformational technological breakthroughs of this age. The importance of AI stems from both the opportunities that it offers and the challenges that it entails. While AI applications hold the promise of economic growth and efficiency gains, they also create significant risks and uncertainty. The potential and perils of AI have thus come to dominate modern discussions of technology and ethics â and although AI was initially allowed to largely develop without guidelines or rules, few would deny that the law is set to play a fundamental role in shaping the future of AI. As the debate over AI is far from over, the need for rigorous analysis has never been greater. This book thus brings together contributors from different fields and backgrounds to explore how the law might provide answers to some of the most pressing questions raised by AI. An outcome of the CatĂłlica Research Centre for the Future of Law and its interdisciplinary working group on Law and Artificial Intelligence, it includes contributions by leading scholars in the fields of technology, ethics and the law.info:eu-repo/semantics/publishedVersio
Multifunctional liquid metal polymer composites
Liquid metals are fast becoming a new class of materials and additives for composites synthesis. In particular, gallium (Ga) and Ga-based liquid metal and alloys exhibit fluidity and frictionless behaviours along with metallic conductivity properties. Liquid metals based on Ga also present low-toxicity and can be readily formed into micro and nanodroplets or utilised in the bulk as conductive liquid substrates. The resulting Ga-based composites present novel physio-chemical behaviours and multifunctional properties that remain to be explored for a range of applications.
In this PhD thesis, the author investigates three liquid metal/polymer composite systems synthesised with low toxicity input materials for remote magnetic actuation, ionic sensing and separation, and cell electrostimulation capabilities.
In the first project, the author aims to develop conductive and magnetic liquid metal polymeric gels. Electrically and magnetic conductive nanodroplets of Ga-based alloys are in-situ synthesised in a polyvinyl alcohol (PVA) solution using mild mechanical agitation methods. The resulting conductive and magnetic gels show additional self-healing properties and demonstrate great potential for the design of soft electronic systems and robotics.
For the second project, Ga-based composites are investigated for the sensing and separation of alkali metal ions. Nanodroplets of Ga-based alloys embedded into a crosslinked PVA flat-sheet composite provide selectivity and sensing capability and stability in mixed ionic alkali metal solutions. The Ga-based flat-sheet composite has implications for the efficient and low-energy recovery of lithium ions from brines.
In the third project, conductive liquid metal polymer composites are prepared for cell culture and electrostimulation. The composite substrates are composed of bulk Ga coated with polydopamine (PDA) to enhance cell adhesion capability. The Ga/PDA composites surfaces show high biocompatibility for cell culture. With added electrical stimulation protocols, the proliferation of mouse embryonic fibroblast cells is promoted. The conductive and biocompatible substrates lead to the use of liquid metals in regenerative medicine and tissue engineering.
Collectively, the findings presented in this thesis provide deep insights and scientific findings for future research directions in the field of liquid metal-based composites for multifunctional materials in soft electronics, separation and sensing, and biomaterials
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