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Nature Neuroscience Mar 2024Microglia are resident immune cells of the central nervous system and play key roles in brain homeostasis. During anesthesia, microglia increase their dynamic process...
Microglia are resident immune cells of the central nervous system and play key roles in brain homeostasis. During anesthesia, microglia increase their dynamic process surveillance and interact more closely with neurons. However, the functional significance of microglial process dynamics and neuronal interaction under anesthesia is largely unknown. Using in vivo two-photon imaging in mice, we show that microglia enhance neuronal activity after the cessation of isoflurane anesthesia. Hyperactive neuron somata are contacted directly by microglial processes, which specifically colocalize with GABAergic boutons. Electron-microscopy-based synaptic reconstruction after two-photon imaging reveals that, during anesthesia, microglial processes enter into the synaptic cleft to shield GABAergic inputs. Microglial ablation or loss of microglial β2-adrenergic receptors prevents post-anesthesia neuronal hyperactivity. Our study demonstrates a previously unappreciated function of microglial process dynamics, which enable microglia to transiently boost post-anesthesia neuronal activity by physically shielding inhibitory inputs.
Topics: Mice; Animals; Microglia; Brain; Synapses; Neurons; Anesthesia
PubMed: 38177340
DOI: 10.1038/s41593-023-01537-8 -
Radiologic Technology Nov 2023To explore the data and supporting evidence for the 2019 statement by the American Association of Physicists in Medicine (AAPM) that recommends limits to the routine use... (Review)
Review
PURPOSE
To explore the data and supporting evidence for the 2019 statement by the American Association of Physicists in Medicine (AAPM) that recommends limits to the routine use of fetal and gonadal shielding in medical imaging.
METHODS
Three researchers searched 5 online databases, selecting articles from scholarly journals and radiology trade publications. Search results were filtered to include literature published from January 1, 2016, to August 9, 2022, to ensure relevance and provide historical background for the 2019 AAPM statement.
RESULTS
The use of patient shielding during medical imaging did not reduce dose, and in certain instances, increased dose received by patients during computed tomography, fluoroscopy, or dental imaging. The use of shielding interfered with technology designed to reduce patient dose, including automatic exposure control and dose modulation. Research showed that errors in shield placement were common and that shields can act as sources of infection or carriers of harmful lead dust.
DISCUSSION
In each article reviewed, a compelling case was made for discontinuing routine patient shielding during radiographic procedures. Serious opposition to the discontinuation of the shielding practice was not found. Opportunities exist for further study into technologists' and the public's understanding of the effects of radiation and technologists' compliance with new shielding policies.
CONCLUSION
The challenges with properly using shielding, paired with recent technological advancements and a new understanding of radiation protection, have negated the need for contact shielding. This legacy practice can be discontinued in clinical settings, and educational materials for technologists and students should be updated to reflect these changes.
Topics: Humans; Radiation Dosage; Tomography, X-Ray Computed; Radiation Protection; Fluoroscopy; Protective Devices
PubMed: 37940176
DOI: No ID Found -
Nano-micro Letters Jul 2023Convincing candidates of flexible (stretchable/compressible) electromagnetic interference shielding nanocomposites are discussed in detail from the views of fabrication,... (Review)
Review
Convincing candidates of flexible (stretchable/compressible) electromagnetic interference shielding nanocomposites are discussed in detail from the views of fabrication, mechanical elasticity and shielding performance. Detailed summary of the relationship between deformation of materials and electromagnetic shielding performance. The future directions and challenges in developing flexible (particularly elastic) shielding nanocomposites are highlighted. With the extensive use of electronic communication technology in integrated circuit systems and wearable devices, electromagnetic interference (EMI) has increased dramatically. The shortcomings of conventional rigid EMI shielding materials include high brittleness, poor comfort, and unsuitability for conforming and deformable applications. Hitherto, flexible (particularly elastic) nanocomposites have attracted enormous interest due to their excellent deformability. However, the current flexible shielding nanocomposites present low mechanical stability and resilience, relatively poor EMI shielding performance, and limited multifunctionality. Herein, the advances in low-dimensional EMI shielding nanomaterials-based elastomers are outlined and a selection of the most remarkable examples is discussed. And the corresponding modification strategies and deformability performance are summarized. Finally, expectations for this quickly increasing sector are discussed, as well as future challenges.
PubMed: 37420119
DOI: 10.1007/s40820-023-01122-5 -
PLoS Pathogens Aug 2023Among the many oral streptococci, Streptococcus pneumoniae (Spn) stands out for the capacity of encapsulated strains to cause invasive infection. Spread beyond upper...
Among the many oral streptococci, Streptococcus pneumoniae (Spn) stands out for the capacity of encapsulated strains to cause invasive infection. Spread beyond upper airways, however, is a biological dead end for the organism, raising the question of the benefits of expending energy to coat its surface in a thick layer of capsular polysaccharide (CPS). In this study, we compare mutants of two serotypes expressing different amounts of CPS and test these in murine models of colonization, invasion infection and transmission. Our analysis of the effect of CPS amount shows that Spn expresses a capsule of sufficient thickness to shield its surface from the deposition of complement and binding of antibody to underlying epitopes. While effective shielding is permissive for invasive infection, its primary contribution to the organism appears to be in the dynamics of colonization. A thicker capsule increases bacterial retention in the nasopharynx, the first event in colonization, and also impedes IL-17-dependent clearance during late colonization. Enhanced colonization is associated with increased opportunity for host-to-host transmission. Additionally, we document substantial differences in CPS amount among clinical isolates of three common serotypes. Together, our findings show that CPS amount is highly variable among Spn and could be an independent determinant affecting host interactions.
Topics: Animals; Mice; Streptococcus pneumoniae; Streptococcus; Polysaccharides; Nasopharynx; Nose; Pneumococcal Infections; Bacterial Capsules
PubMed: 37540710
DOI: 10.1371/journal.ppat.1011509 -
Nano Letters Nov 2023Lithium-sulfur batteries (LiSBs) are promising next-generation batteries because of their low cost and high theoretical energy densities. Despite remarkable advances...
Lithium-sulfur batteries (LiSBs) are promising next-generation batteries because of their low cost and high theoretical energy densities. Despite remarkable advances over the decades, polysulfide (PS) shuttling during battery cycling remains a challenge in the development of commercial LiSBs and is accelerated under practical conditions. Herein, we report a permselective ionic shield between the electrodes that blocks PS shuttles and passes Li ions to high-performance LiSBs. This shield is easily built onto the separator by ionic complexation and intermolecular bonding of functional polymers, thereby improving the battery performance and safety. The LiSB with the developed shield delivers a remarkable discharge capacity of 917 mAh g after 1000 cycles at 2 C. In addition, the behavior of LiSBs under practical conditions that can realize a high energy density is investigated to achieve the optimal balance in this system. This study provides new insights into the imminent development of separators for practical LiSBs.
PubMed: 37943575
DOI: 10.1021/acs.nanolett.3c03021 -
Nature Materials Nov 2023The mechanical properties of the extracellular matrix dictate tissue behaviour. In epithelial tissues, laminin is a very abundant extracellular matrix component and a...
The mechanical properties of the extracellular matrix dictate tissue behaviour. In epithelial tissues, laminin is a very abundant extracellular matrix component and a key supporting element. Here we show that laminin hinders the mechanoresponses of breast epithelial cells by shielding the nucleus from mechanical deformation. Coating substrates with laminin-111-unlike fibronectin or collagen I-impairs cell response to substrate rigidity and YAP nuclear localization. Blocking the laminin-specific integrin β4 increases nuclear YAP ratios in a rigidity-dependent manner without affecting the cell forces or focal adhesions. By combining mechanical perturbations and mathematical modelling, we show that β4 integrins establish a mechanical linkage between the substrate and keratin cytoskeleton, which stiffens the network and shields the nucleus from actomyosin-mediated mechanical deformation. In turn, this affects the nuclear YAP mechanoresponses, chromatin methylation and cell invasion in three dimensions. Our results demonstrate a mechanism by which tissues can regulate their sensitivity to mechanical signals.
Topics: Laminin; Cell Adhesion; Keratins; Extracellular Matrix; Fibronectins; Cytoskeleton; Integrins
PubMed: 37709930
DOI: 10.1038/s41563-023-01657-3 -
Federal Practitioner : For the Health... Nov 2023To address the COVID-19 pandemic and future threats, VA leadership assembled research and clinical teams to coordinate a unified response, which included creating the VA...
BACKGROUND
To address the COVID-19 pandemic and future threats, VA leadership assembled research and clinical teams to coordinate a unified response, which included creating the VA Science and Health Initiative to Combat Infectious and Emerging Life-Threatening Diseases (VA SHIELD).
OBSERVATIONS
VA SHIELD is a comprehensive specimen and data repository. It links specific types of biospecimens with data regarding genetics, exposure, and disease risk by connecting data sources and the collections of biospecimens across clinical and research environments. Researchers can test novel diagnostic platforms and therapeutics for new and existing diseases, allowing for an expedited, more robust, and informed response. The existing longitudinal disease risk-factor information, records of causal processes, and outcomes data present an unparalleled opportunity to optimize prevention, diagnosis, and treatment of many acute and chronic diseases.
CONCLUSIONS
VA SHIELD will expand to become an enterprise resource for investigators and public health officials. The alignment of basic science, clinical, and translational research goals under one governance is a significant advancement. VA SHIELD has the opportunity to transform the VA research enterprise by creating an entirely new biorepository.
PubMed: 38577305
DOI: 10.12788/fp.0424 -
Attention, Perception & Psychophysics Jan 2024Magnetoencephalography (MEG) can measure brain activity in ms-level temporal resolution. MEG sensors are super sensitive devices for magnetic signals of the brain but...
Magnetoencephalography (MEG) can measure brain activity in ms-level temporal resolution. MEG sensors are super sensitive devices for magnetic signals of the brain but are also prone to electromagnetic interferences. The MEG device is located inside the magnetically shielded room (MSR), and any monitoring device used inside the MSR requires special shielding and its location must be carefully selected to suppress electromagnetic interference. Eye-tracker measures eye movements, providing spatial location of the gaze, pupil diameters, and eye blinks. Eye tracking in MEG enables, for example, categorization of the MEG data based on gaze position and interactive stimulus using gaze position. Combining the methods together will require considering the electromagnetic interference for the MEG-that is, additional shielding, positioning of the eye tracker, and subject-specific issues related to make-up and eye-corrective lenses.
PubMed: 38291204
DOI: 10.3758/s13414-024-02847-0 -
Molecules (Basel, Switzerland) Jul 2023The rapid advancement of electronic communication technology has greatly aided human productivity and quality of life, but it has also resulted in significant... (Review)
Review
The rapid advancement of electronic communication technology has greatly aided human productivity and quality of life, but it has also resulted in significant electromagnetic pollution issues. Traditional metals and alloys are often used for electromagnetic interference (EMI) shielding due to their excellent electrical conductivity. However, they have drawbacks such as being heavy, expensive, and having low corrosion resistance, which limits their application in electromagnetic shielding. Therefore, it is crucial to develop novel EMI shielding materials. Polymers, being highly flexible, corrosion-resistant, and possessing high specific strength, are frequently employed in electromagnetic shielding materials. In this review, we firstly introduce the basic theory of electromagnetic shielding. Then, we outline the processing methods and recent developments of polymer-based electromagnetic shielding composites, including uniform-, foam-, layered-, and segregated structures. Lastly, we present the challenges and prospects for the field, aiming to provide direction and inspiration for the study of polymer-based electromagnetic shielding composite materials.
PubMed: 37570598
DOI: 10.3390/molecules28155628 -
Molecules (Basel, Switzerland) Jul 2023A series of highly fluorinated polyimide/allomelanin nanoparticles (FPI/AMNPs) films were prepared with FPI as the matrix and AMNPs as the filler. Due to the formation...
A series of highly fluorinated polyimide/allomelanin nanoparticles (FPI/AMNPs) films were prepared with FPI as the matrix and AMNPs as the filler. Due to the formation of hydrogen bonds, significantly reinforced mechanical and UV-shielding properties are acquired. Stress-strain curves demonstrated a maximum tensile strength of 150.59 MPa and a fracture elongation of 1.40% (0.7 wt.% AMNPs), respectively, 1.78 and 1.56× that of pure FPI. The measurements of the UV-vis spectrum, photodegradation of curcumin and repeated running tests confirmed the splendid UV-shielding capabilities of FPI/AMNPs films. The enhancement mechanisms, such as synergistic UV absorption of the charge transfer complexes in FPI and AMNPs and photothermal conversion, were the reasons for its exceptional UV shielding. The excellent comprehensive properties above enable FPI/AMNPs nanocomposites to be potential candidates in the field of UV shielding.
PubMed: 37513395
DOI: 10.3390/molecules28145523