146 research outputs found
Bacteriophage and their potential roles in the human oral cavity.
The human oral cavity provides the perfect portal of entry for viruses and bacteria in the environment to access new hosts. Hence, the oral cavity is one of the most densely populated habitats of the human body containing some 6 billion bacteria and potentially 35 times that many viruses. The role of these viral communities remains unclear; however, many are bacteriophage that may have active roles in shaping the ecology of oral bacterial communities. Other implications for the presence of such vast oral phage communities include accelerating the molecular diversity of their bacterial hosts as both host and phage mutate to gain evolutionary advantages. Additional roles include the acquisitions of new gene functions through lysogenic conversions that may provide selective advantages to host bacteria in response to antibiotics or other types of disturbances, and protection of the human host from invading pathogens by binding to and preventing pathogens from crossing oral mucosal barriers. Recent evidence suggests that phage may be more involved in periodontal diseases than were previously thought, as their compositions in the subgingival crevice in moderate to severe periodontitis are known to be significantly altered. However, it is unclear to what extent they contribute to dysbiosis or the transition of the microbial community into a state promoting oral disease. Bacteriophage communities are distinct in saliva compared to sub- and supragingival areas, suggesting that different oral biogeographic niches have unique phage ecology shaping their bacterial biota. In this review, we summarize what is known about phage communities in the oral cavity, the possible contributions of phage in shaping oral bacterial ecology, and the risks to public health oral phage may pose through their potential to spread antibiotic resistance gene functions to close contacts
Combining Soft Polysilazanes with Melt-Shear Organization of Core–Shell Particles: On the Road to Polymer-Templated Porous Ceramics
The preparation of ordered macroporous SiCN ceramics has attracted significant interest and is an attractive area for various applications, e.g., in the fields of catalysis, gas adsorption, or membranes. Non-oxidic ceramics, such as SiCN, own a great stability based on the covalent bonds between the containing elements, which leads to interesting properties concerning resistance and stability at high temperature. Their peculiar properties have become more and more important for a manifold of applications, like catalysis or separation processes, at high temperatures. Within this work, a feasible approach for the preparation of ordered porous materials by taking advantage of polymer-derived ceramics is presented. To gain access to free-standing films consisting of porous ceramic materials, the combination of monodisperse organic polymer-based colloids with diameters of 130 nm and 180 nm featuring a processable preceramic polymer is essential. For this purpose, the tailored design of hybrid organic/inorganic particles featuring anchoring sites for a preceramic polymer in the soft shell material is developed. Moreover, polymer-based core particles are used as sacrificial template for the generation of pores, while the preceramic shell polymer can be converted to the ceramic matrix after thermal treatment. Two different routes for the polymer particles, which can be obtained by emulsion polymerization, are followed for covalently linking the preceramic polysilazane Durazane1800 (Merck, Germany): (i) Free radical polymerization and (ii) atom transfer radical polymerization (ATRP) conditions. These hybrid hard core/soft shell particles can be processed via the so-called melt-shear organization for the one-step preparation of free-standing particle films. A major advantage of this technique is the absence of any solvent or dispersion medium, enabling the core particles to merge into ordered particle stacks based on the soft preceramic shell. Subsequent ceramization of the colloidal crystal films leads to core particle degradation and transformation into porous ceramics with ceramic yields of 18–54%
Combining Soft Polysilazanes with Melt-Shear Organization of Core–Shell Particles: On the Road to Polymer-Templated Porous Ceramics
The preparation of ordered macroporous SiCN ceramics has attracted significant interest and is an attractive area for various applications, e.g., in the fields of catalysis, gas adsorption, or membranes. Non-oxidic ceramics, such as SiCN, own a great stability based on the covalent bonds between the containing elements, which leads to interesting properties concerning resistance and stability at high temperature. Their peculiar properties have become more and more important for a manifold of applications, like catalysis or separation processes, at high temperatures. Within this work, a feasible approach for the preparation of ordered porous materials by taking advantage of polymer-derived ceramics is presented. To gain access to free-standing films consisting of porous ceramic materials, the combination of monodisperse organic polymer-based colloids with diameters of 130 nm and 180 nm featuring a processable preceramic polymer is essential. For this purpose, the tailored design of hybrid organic/inorganic particles featuring anchoring sites for a preceramic polymer in the soft shell material is developed. Moreover, polymer-based core particles are used as sacrificial template for the generation of pores, while the preceramic shell polymer can be converted to the ceramic matrix after thermal treatment. Two different routes for the polymer particles, which can be obtained by emulsion polymerization, are followed for covalently linking the preceramic polysilazane Durazane1800 (Merck, Germany): (i) Free radical polymerization and (ii) atom transfer radical polymerization (ATRP) conditions. These hybrid hard core/soft shell particles can be processed via the so-called melt-shear organization for the one-step preparation of free-standing particle films. A major advantage of this technique is the absence of any solvent or dispersion medium, enabling the core particles to merge into ordered particle stacks based on the soft preceramic shell. Subsequent ceramization of the colloidal crystal films leads to core particle degradation and transformation into porous ceramics with ceramic yields of 18–54%
Is More, Better? Relationships of Multiple Psychological Well-Being Facets with Cardiometabolic Disease
Objective: Cardiometabolic disease (CMD) is a leading cause of death and disability worldwide. Assessments of psychological well-being taken at one time point are linked to reduced cardiometabolic risk, but psychological well-being may change over time and how longitudinal trajectories of psychological well-being may be related to CMD risk remains unclear. Furthermore, psychological well-being is a multidimensional construct comprised of distinct facets, but no work has examined whether sustaining high levels of multiple facets may confer additive protection. This study tested if trajectories of four psychological well-being facets would be associated with lower risk of self-reported nonfatal CMD. Method: Participants were 4,006 adults aged ≥50 years in the English Longitudinal study of Ageing followed for 18 years at biyearly intervals. Psychological well-being facets were measured in Waves 1–5 using subscales of the Control, Autonomy, Satisfaction, and Pleasure scale. Latent class growth modeling defined trajectories of each facet. Incident CMD cases were self-reported at Waves 6–9. Cox regression models estimated likelihood of incident CMD associated with trajectories of each facet individually and additively (i.e., having persistently high levels on multiple facets over time). Results: After adjusting for relevant covariates, CMD risk was lower for adults with persistently high versus persistently low levels of control and autonomy. When considering potential additive effects, lower CMD risk was also related to experiencing persistently high levels of ≥2 versus 0 psychological well-being facets. Conclusions: Findings suggest having and sustaining multiple facets of psychological well-being is beneficial for cardiometabolic health, and that effects may be additive
Robust Tumor Segmentation with Hyperspectral Imaging and Graph Neural Networks
Segmenting the boundary between tumor and healthy tissue during surgical
cancer resection poses a significant challenge. In recent years, Hyperspectral
Imaging (HSI) combined with Machine Learning (ML) has emerged as a promising
solution. However, due to the extensive information contained within the
spectral domain, most ML approaches primarily classify individual HSI
(super-)pixels, or tiles, without taking into account their spatial context. In
this paper, we propose an improved methodology that leverages the spatial
context of tiles for more robust and smoother segmentation. To address the
irregular shapes of tiles, we utilize Graph Neural Networks (GNNs) to propagate
context information across neighboring regions. The features for each tile
within the graph are extracted using a Convolutional Neural Network (CNN),
which is trained simultaneously with the subsequent GNN. Moreover, we
incorporate local image quality metrics into the loss function to enhance the
training procedure's robustness against low-quality regions in the training
images. We demonstrate the superiority of our proposed method using a clinical
ex vivo dataset consisting of 51 HSI images from 30 patients. Despite the
limited dataset, the GNN-based model significantly outperforms context-agnostic
approaches, accurately distinguishing between healthy and tumor tissues, even
in images from previously unseen patients. Furthermore, we show that our
carefully designed loss function, accounting for local image quality, results
in additional improvements. Our findings demonstrate that context-aware GNN
algorithms can robustly find tumor demarcations on HSI images, ultimately
contributing to better surgery success and patient outcome.Comment: 11 pages, 6 figure
Molecular mechanisms controlling synaptic recruitment of GluA4 subunit-containing AMPAreceptors
Synaptic recruitment of AMPA receptors (AMPARs) represents a key postsynaptic mechanism driving functional development and maturation of glutamatergic synapses. At immature hippocampal synapses, PKA-driven synaptic insertion of GluA4 is the predominant mechanism for synaptic reinforcement. However, the physiological significance and molecular determinants of this developmentally restricted form of plasticity are not known. Here we show that PKA activation leads to insertion of GluA4 to synaptic sites with initially weak or silent AMPAR-mediated transmission. This effect depends on a novel mechanism involving the extreme C-terminal end of GluA4, which interacts with the membrane proximal region of the C-terminal domain to control GluA4 trafficking. In the absence of GluA4, strengthening of AMPAR-mediated transmission during postnatal development was significantly delayed. These data suggest that the GluA4-mediated activation of silent synapses is a critical mechanism facilitating the functional maturation of glutamatergic circuitry during the critical period of experience-dependent fine-tuning
Dapagliflozin and Diuretic Use in Patients With Heart Failure and Reduced Ejection Fraction in DAPA-HF
Background: In the DAPA-HF trial (Dapagliflozin and Prevention of Adverse-Outcomes in Heart Failure), the sodium-glucose cotransporter 2 inhibitor dapagliflozin reduced the risk of worsening heart failure and death in patients with heart failure and reduced ejection fraction. We examined the efficacy and tolerability of dapagliflozin in relation to background diuretic treatment and change in diuretic therapy after randomization to dapagliflozin or placebo. Methods: We examined the effects of study treatment in the following subgroups: No diuretic and diuretic dose equivalent to furosemide 40 mg daily at baseline. We examined the primary composite end point of cardiovascular death or a worsening heart failure event and its components, all-cause death and symptoms. Results: Of 4616 analyzable patients, 736 (15.9%) were on no diuretic, 1311 (28.4%) were on 40 mg. Compared with placebo, dapagliflozin reduced the risk of the primary end point across each of these subgroups: Hazard ratios were 0.57 (95% CI, 0.36-0.92), 0.83 (95% CI, 0.63-1.10), 0.77 (95% CI, 0.60-0.99), and 0.78 (95% CI, 0.63-0.97), respectively (P for interaction=0.61). The hazard ratio in patients taking any diuretic was 0.78 (95% CI, 0.68-0.90). Improvements in symptoms and treatment toleration were consistent across the diuretic subgroups. Diuretic dose did not change in most patients during follow-up, and mean diuretic dose did not differ between the dapagliflozin and placebo groups after randomization. Conclusions: The efficacy and safety of dapagliflozin were consistent across the diuretic subgroups examined in DAPA-HF
Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects
<p>Abstract</p> <p>Background</p> <p>The aim of this study was to evaluate the usefulness of an ultrasound-based method of examining extensor muscle architecture, especially the parameters important for force development. This paper presents the combination of two non-invasive methods for studying the extensor muscle architecture using ultrasound simultaneously with finger extension force measurements.</p> <p>Methods</p> <p>M. extensor digitorum communis (EDC) was examined in 40 healthy subjects, 20 women and 20 men, aged 35–73 years. Ultrasound measurements were made in a relaxed position of the hand as well as in full contraction. Muscle cross-sectional area (CSA), pennation angle and contraction patterns were measured with ultrasound, and muscle volume and fascicle length were also estimated. Finger extension force was measured using a newly developed finger force measurement device.</p> <p>Results</p> <p>The following muscle parameters were determined: CSA, circumference, thickness, pennation angles and changes in shape of the muscle CSA. The mean EDC volume in men was 28.3 cm<sup>3 </sup>and in women 16.6 cm<sup>3</sup>. The mean CSA was 2.54 cm<sup>2 </sup>for men and 1.84 cm<sup>2 </sup>for women. The mean pennation angle for men was 6.5° and for women 5.5°. The mean muscle thickness for men was 1.2 cm and for women 0.76 cm. The mean fascicle length for men was 7.3 cm and for women 5.0 cm. Significant differences were found between men and women regarding EDC volume (p < 0.001), CSA (p < 0.001), pennation angle (p < 0.05), muscle thickness (p < 0.001), fascicle length (p < 0.001) and finger force (p < 0.001). Changes in the shape of muscle architecture during contraction were more pronounced in men than women (p < 0.01). The mean finger extension force for men was 96.7 N and for women 39.6 N. Muscle parameters related to the extension force differed between men and women. For men the muscle volume and muscle CSA were related to extension force, while for women muscle thickness was related to the extension force.</p> <p>Conclusion</p> <p>Ultrasound is a useful tool for studying muscle architectures in EDC. Muscle parameters of importance for force development were identified. Knowledge concerning the correlation between muscle dynamics and force is of importance for the development of new hand training programmes and rehabilitation after surgery.</p
Science Forum: Consensus-based guidance for conducting and reporting multi-analyst studies
Any large dataset can be analyzed in a number of ways, and it is possible that the use of different analysis strategies will lead to different results and conclusions. One way to assess whether the results obtained depend on the analysis strategy chosen is to employ multiple analysts and leave each of them free to follow their own approach. Here, we present consensus-based guidance for conducting and reporting such multi-analyst studies, and we discuss how broader adoption of the multi-analyst approach has the potential to strengthen the robustness of results and conclusions obtained from analyses of datasets in basic and applied research
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