-
Medicina (Kaunas, Lithuania) Oct 2022The antimicrobial efficacy of a nonthermal atmospheric-pressure plasma jet (NAPPJ) on dental impression materials was investigated. Type 3 polyvinyl siloxane was used...
The antimicrobial efficacy of a nonthermal atmospheric-pressure plasma jet (NAPPJ) on dental impression materials was investigated. Type 3 polyvinyl siloxane was used as the impression material, and air and nitrogen NAPPJ were applied. The antibacterial effect of the NAPPJ was measured using the number of colony-forming units (CFUs) and scanning electron microscopy (SEM) images of . Surface chemical characteristics of the impression material were examined using X-ray photoelectron spectroscopy (XPS) and contact angle measurement. Additionally, physical properties were analyzed through surface roughness measurement, detail reproduction, and strain-in-compression test. Compared with the control group, the plasma treatment group showed ruptured bacteria membranes, destroyed bacteria structures, a significant reduction in the number of CFUs, and a significantly reduced contact angle. Further, XPS analysis showed that their surface was significantly richer in hydroxyl groups. The surface roughness, detail reproduction, and strain-in-compression results indicated no significant differences between the plasma treatment and control groups. NAPPJ treatment could remove bacteria from polyvinyl siloxane dental impression materials without changing the surface's physical properties. Therefore, it is considered a promising method for disinfection.
Topics: Humans; Plasma Gases; Surface Properties; Materials Testing; Dental Impression Materials
PubMed: 36363513
DOI: 10.3390/medicina58111556 -
PloS One 2022The wettability of a polymer surface plays a critical role in cell-cell interaction and behavior. The degree to which a surface is hydrophobic or hydrophilic affects the...
The wettability of a polymer surface plays a critical role in cell-cell interaction and behavior. The degree to which a surface is hydrophobic or hydrophilic affects the adhesion and behavior of cells. Two distinct techniques for patterning the surface wettability of a Cyclic Olefin Copolymer (COC) substrate were developed and investigated in this article for the purpose of patterning cell growth. These include oxygen plasma treatment and graphene oxide (GO) coating to alter the wettability of the COC substrate and create hydrophilic patterned regions on a hydrophobic surface. When the two techniques are compared, patterning the surface of COC using GO film results in a more stable wettability over time and increases the roughness of the patterned area. Interestingly, both developed techniques were effective at patterning the COC surface's wettability, which modulated cell adhesion and resulted in micropatterning of cell growth. The novel methods described herein can be used in the fields of cell and tissue culture as well as in the development of new biological assays.
Topics: Graphite; Hydrophobic and Hydrophilic Interactions; Polymers; Surface Properties; Wettability
PubMed: 35709175
DOI: 10.1371/journal.pone.0269914 -
PloS One 2023Species Distribution Models often include spatial effects which may improve prediction at unsampled locations and reduce Type I errors when identifying environmental...
Species Distribution Models often include spatial effects which may improve prediction at unsampled locations and reduce Type I errors when identifying environmental drivers. In some cases ecologists try to ecologically interpret the spatial patterns displayed by the spatial effect. However, spatial autocorrelation may be driven by many different unaccounted drivers, which complicates the ecological interpretation of fitted spatial effects. This study aims to provide a practical demonstration that spatial effects are able to smooth the effect of multiple unaccounted drivers. To do so we use a simulation study that fit model-based spatial models using both geostatistics and 2D smoothing splines. Results show that fitted spatial effects resemble the sum of the unaccounted covariate surface(s) in each model.
Topics: Computer Simulation; Spatial Analysis
PubMed: 37253039
DOI: 10.1371/journal.pone.0285463 -
Journal of Applied Statistics 2021An important feature in dentistry is teeth gloss. During an intervention, the doctor applies a resin and a polishing to achieve the lowest roughness and the highest...
An important feature in dentistry is teeth gloss. During an intervention, the doctor applies a resin and a polishing to achieve the lowest roughness and the highest gloss possible. This work aims to evaluate the effect of four polishing protocols in teeth surface roughness and gloss when combined with two different resins and eventually indicate the best combination (treatment). An atomic force microscope is used for measuring the roughness of a dental surface surrogate. We consider a shared parameters approach for linking the information carried by those two correlated variables. The model fitted to the gloss considers some features of the roughness, namely the information conveyed by a set of spatial structured random effects, specific to each treatment, and the within treatment variance, which allows interpreting how the heterogeneity and the variability of the surface roughness impacts a tooth gloss. The statistical model here developed is an alternative to the "traditional" two-way ANOVA used in dentistry journals. The results, using the recent R-NIMBLE package in R, show that variability characteristics of the surface's roughness are central for explaining differences among the gloss achieved after each treatment and not just the mean roughness of that surface.
PubMed: 35707688
DOI: 10.1080/02664763.2020.1724273 -
Journal of Anatomy Sep 2022Biological armors derive their mechanical integrity in part from their geometric architectures, often involving tessellations: individual structural elements tiled...
Biological armors derive their mechanical integrity in part from their geometric architectures, often involving tessellations: individual structural elements tiled together to form surface shells. The carapace of boxfish, for example, is composed of mineralized polygonal plates, called scutes, arranged in a complex geometric pattern and nearly completely encasing the body. In contrast to artificial armors, the boxfish exoskeleton grows with the fish; the relationship between the tessellation and the gross structure of the armor is therefore critical to sustained protection throughout growth. To clarify whether or how the boxfish tessellation is maintained or altered with age, we quantify architectural aspects of the tessellated carapace of the longhorn cowfish Lactoria cornuta through ontogeny (across nearly an order of magnitude in standard length) and in a high-throughput fashion, using high-resolution microCT data and segmentation algorithms to characterize the hundreds of scutes that cover each individual. We show that carapace growth is canalized with little variability across individuals: rather than continually adding scutes to enlarge the carapace surface, the number of scutes is surprisingly constant, with scutes increasing in volume, thickness, and especially width with age. As cowfish and their scutes grow, scutes become comparatively thinner, with the scutes at the edges (weak points in a boxy architecture) being some of the thickest and most reinforced in younger animals and thinning most slowly across ontogeny. In contrast, smaller scutes with more variable curvature were found in the limited areas of more complex topology (e.g., around fin insertions, mouth, and anus). Measurements of Gaussian and mean curvature illustrate that cowfish are essentially tessellated boxes throughout life: predominantly zero curvature surfaces comprised of mostly flat scutes, and with scutes with sharp bends used sparingly to form box edges. Since growth of a curved, tiled surface with a fixed number of tiles would require tile restructuring to accommodate the surface's changing radius of curvature, our results therefore illustrate a previously unappreciated advantage of the odd boxfish morphology: by having predominantly flat surfaces, it is the box-like body form that in fact permits a relatively straightforward growth system of this tessellated architecture (i.e., where material is added to scute edges). Our characterization of the ontogeny and maintenance of the carapace tessellation provides insights into the potentially conflicting mechanical, geometric, and developmental constraints of this species but also perspectives into natural strategies for constructing mutable tiled architectures.
Topics: Animal Shells; Animals; Skin; Tetraodontiformes; X-Ray Microtomography
PubMed: 35638264
DOI: 10.1111/joa.13692 -
Frontiers in Digital Health 2023
PubMed: 36895323
DOI: 10.3389/fdgth.2023.1150875 -
Materials (Basel, Switzerland) Jul 2022Electric discharge machining with a powder mix dielectric is a promising technique to harden a work piece's surface using electricity with a high energy density. The...
Electric discharge machining with a powder mix dielectric is a promising technique to harden a work piece's surface using electricity with a high energy density. The quality of the electrical discharge-machined surface is related to its surface integrity in which the surface's roughness, residual stresses, micro hardness and surface micro cracks are some of the major factors. In this research, graphite powder was mixed in a dielectric with a particle size of 20 µm, 30 µm, and 40 µm, with the concentration of the graphite powder ranging from 2 g/L to 4 g/L. Moreover, the peak current and pulse time on were also coupled with an additive of graphite powder to investigate the effect on the surface quality, i.e., the recast layer thickness, micro hardness and crater depth as well as the material removal rate (MRR) and tool wear rate (TWR). A Box-Behnken design was employed to design the experiments and the experimental results revealed that the graphite powder size and concentration coupled with the electrical parameters (peak current and pulse time on) significantly influenced the recast layer thickness, micro hardness, crater size, MRR and TWR. The crater depth and micro hardness were maximized at a higher concentration and particle size, while the recast layer thickness was reduced with a higher gain size.
PubMed: 35888399
DOI: 10.3390/ma15144932 -
Caries Research 2021The oral microbiome is unique at inter and intra-individual levels at various sites due to physical and biological factors. This study aimed to compare the bacterial...
The oral microbiome is unique at inter and intra-individual levels at various sites due to physical and biological factors. This study aimed to compare the bacterial composition of supragingival biofilms collected from enamel sites with different caries activity, from active and inactive-caries subjects, and from caries-free (CF) subjects. Twenty-two individuals (aged between 13 and 76 years old; med = 23.5 years old) were allocated into 3 groups: caries-active (CA) (n = 10), caries-inactive (CI) (n = 6), and CF (n = 6). From the CA group, 3 sites were sampled: CA (active non-cavitated lesion), CI (inactive non-cavitated lesion), and sound enamel surface (S). From the subjects of the CI group, biofilm from a CI lesion was collected (INCL), while for the CF subjects, a pool of biofilm from sound enamel surfaces was sampled. The total RNA was extracted, and cDNA libraries were prepared and paired-end sequenced (Illumina HiSeq 3,000). Final dental biofilm samples analysed from CA was 16 (ANCL-CA = 6, INCL-CA = 4, S-CA = 6); from CI, 3 (INCL-CI = 3); and from CF, 6 (S-CF = 6) (some samples were lost by insufficient genetic material). Read sequences were processed and analysed using the Metagenomics RAST server. High-quality sequences (3,542,190) were clustered into operational taxonomic units (97% identity; SILVA SSU), representing 915 genera belonging to 29 phyla (higher abundant: Actinobacteria, Firmicutes, Bacteroidetes, and Fusobacteria). The presence of a core microbiome was observed (123 shared genera). The alpha diversity analysis showed less bacterial diversity in disease (S-CA) compared to health (S-CF). The dominant genera included Actinomyces, Corynebacterium, Capnocytophaga, Leptotrichia, Veillonella, Prevotella, Streptococcus, Eubacterium, and Neisseria. Veillonella and Leptotrichia were related with disease and Prevotella with health. Corynebacterium, Capnocytophaga, and Actinomyces clustered together presenting high abundance in health and disease. The Metric Multidimensional Scaling Ordination analysis shows that sites from active subjects (ANCL-CA, INCL-CA, and S-CA) are closer to each other than either INCL-CI subjects or S-CF subjects. In conclusion, supragingival bacterial communities presented intra-individual similarities, but inter-individual diversity and difference in bacterial composition reveal that the subject's caries activity status matters more than sites.
Topics: Adolescent; Adult; Aged; Biofilms; Dental Caries; Dental Caries Susceptibility; Humans; Microbiota; Middle Aged; RNA, Ribosomal, 16S; Young Adult
PubMed: 34380135
DOI: 10.1159/000518963 -
Neurosurgical Focus Aug 2021Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its...
OBJECTIVE
Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its limitations. Except for ultrasound, other methods are expensive. Three-dimensional virtual reconstruction and surgical simulation using 3D volume rendering (VR) is an economical and excellent technique for preoperative surgical planning and image-guided neurosurgery. In this article, the authors discuss several nuances of the 3D VR technique that have not yet been described.
METHODS
The authors included 6 patients with supratentorial gliomas who underwent surgery between January 2019 and March 2021. Preoperative clinical data, including patient demographics, preoperative planning details (done using the VR technique), and intraoperative details, including relevant photos and videos, were collected. RadiAnt software was used for generating virtual 3D images using the VR technique on a computer running Microsoft Windows.
RESULTS
The 3D VR technique assists in glioma surgery with a preoperative simulation of the skin incision and craniotomy, virtual cortical surface marking and navigation for deep-seated gliomas, preoperative visualization of morbid cortical surface and venous anatomy in surfacing gliomas, identifying the intervenous surgical corridor in both surfacing and deep-seated gliomas, and pre- and postoperative virtual 3D images highlighting the exact spatial geometric residual tumor location and extent of resection for low-grade gliomas (LGGs).
CONCLUSIONS
Image-guided neurosurgery with the 3D VR technique using RadiAnt software is an economical, easy-to-learn, and user-friendly method of simulating glioma surgery, especially in resource-constrained countries where expensive neuronavigation systems are not readily available. Apart from cortical sulci/gyri anatomy, FLAIR sequences are ideal for the 3D visualization of nonenhancing diffuse LGGs using the VR technique. In addition to cortical vessels (especially veins), contrast MRI sequences are perfect for the 3D visualization of contrast-enhancing high-grade gliomas.
Topics: Brain Neoplasms; Glioma; Humans; Imaging, Three-Dimensional; Neuronavigation; Virtual Reality
PubMed: 34333461
DOI: 10.3171/2021.5.FOCUS21236 -
American Journal of Botany Jul 2022Pollination in many aquatic plants takes place on the water surface, and the male flowers or stamens often produce gas bubbles underwater; however, the generation...
PREMISE
Pollination in many aquatic plants takes place on the water surface, and the male flowers or stamens often produce gas bubbles underwater; however, the generation mechanism and function of these bubbles are unknown.
METHODS
A common submerged plant, Hydrilla verticillata, was used as experimental material to observe the structure of male flowers, analyze the process of bubble generation, and simulate the movement process of the male flower with attached gas bubble in water.
RESULTS
The aerenchyma inside the male plants of H. verticillata transported the gas produced by the plant's branches during photosynthesis to the male flower, and the formed gas bubbles became attached to the edge of the perianth. The gas accumulation rate in the attached bubbles increased with light intensity. Once the bubble diameter increased to approximately 3.3 mm, the male flowers with the bubble detached from the plant and floated to the water surface. The removal of the attached bubbles did not affect the male flower detached from the plant; however, the surfacing of male flowers without gas bubbles was easily prevented by the plant's branches in the water, and they could not reach the water surface to complete pollen dispersal.
CONCLUSIONS
The gas bubbles produced by male flowers of H. verticillata came from the gas produced by branches under light. These bubbles can help ascending male flowers bypass the obstacles in water and reach the surface to complete pollination.
Topics: Flowers; Hydrocharitaceae; Plants; Pollen; Pollination; Water
PubMed: 35686633
DOI: 10.1002/ajb2.16022