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Abstract

Periodontal disease and diabetes mellitus have been said to have a two-way relationship, with diabetes leading to oral disease and periodontitis exacerbating hyperglycemia. The universal biologic mechanisms and demographic and behavioral risk drivers, underlying these associations in both directions, are also described.

Both the diseases are chronic and they are affecting large population worldwide. Periodontitis is also recognized as the sixth major complication of diabetes, while diabetes mellitus is a metabolic disorder which has an impact on the global health and plays a crucial role in the pathogenesis of periodontitis.

The aim of this article is to illustrate a systematic and comprehensive analysis of the literature, on the mutual relationship between diabetes mellitus and periodontal diseases,

trying to identify if the prevalence of periodontitis is higher in diabetics or if the incidence of diabetes is greater in patients with periodontal disease. Moreover, our intention is to increase the level of awareness of diabetologists and dentists about the interaction between this two pathologies.

Oral and periodontal health should be promoted as integral components of diabetes management. Dental professionals can detect unrecognized potential dysglycemia and refer for medical examination. Furthermore, the control of periodontal disease may enhance glycemic control which contributes to a better control of periodontal disease.

Abstract

The Modal Propellant Gauging (MPG) experiment has demonstrated sub-1% gauging accuracy under laboratory conditions on both flight hardware and subscale tanks. Recently, MPG was adapted for flight on Blue Origin's New Shepard vehicle and has flown twice, achieving equilibrated, zero-g surface configurations of propellant simulant at three different fill fractions. Flight data from MPG missions on New Shepard P7 and P9 show agreement between known and measured propellant levels of 0.3% for the fill fractions investigated in the present study. Two approaches for estimating zero-g propellant mass are described here. Both approaches rely on measuring shifts in modal frequencies of a tank excited by acoustic surface waves and subject to fluid mass loading by the propellant. In the first approach, shifts in the lowest mode frequency (LMF) are measured and associated with liquid fill-level changes. In the second approach, 1-g modal spectra at a range of known fill levels are used in a cross-correlation calculation to predict fill levels associated with a zero-g modal spectrum. Flight data for both approaches are consistent with finite element predictions using a simple fluid–structure interaction model. In both settled and unsettled microgravity environments, MPG meets or exceeds NASA Roadmap goals for in-space propellant mass gauging.

Abstract

Small, airless bodies are covered by a layer of regolith composed of particles ranging from μm-size dust to cm-size pebbles that evolve under conditions very different than those on Earth. Flight-based microgravity experiments investigating low-velocity collisions of cm-size projectiles into regolith have revealed that certain impact events result in a mass transfer from the target regolith onto the surface of the projectile. The key parameters that produce these events need to be characterized to understand the mechanical behavior of granular media, which is composed of the surfaces of small bodies. We carried out flight and ground-based research campaigns designed to investigate these mass transfer events. The goals of our experimental campaigns were (1) to identify projectile energy thresholds that influence mass transfer outcomes in low-energy collision events between cm-size projectiles and μm-size regolith, (2) to determine whether these mass transfer events required a microgravity environment to be observed, and (3) to determine whether the rebound portion of these collision events could be replicated in a laboratory drop tower environment. We found that (1) mass transfer events occurred for projectile rebound accelerations <7.8 m/s2 and we were unable to identify a corresponding impact velocity threshold, (2) mass transfer events require a microgravity environment, and (3) ourdrop tower experiments were able to produce mass transfer events. However, drop tower experiments do not exactly reproduce the free-particle impacts and rebound of the long-duration microgravity experiments and yielded systematically lower amounts of the overall mass transferred.

Abstract

Multiple private companies are building suborbital reusable launch vehicles possessing vastly different designs. Many of these companies originally focused on space tourism; however, revolutionary applications for scientific and engineering research as well as technology demonstrations and instrument development are emerging. The dramatic reduction in cost over traditional launch systems as well as a guaranteed (and rapid) safe payload return enable many new launch vehicle applications. These new capabilities will essentially move the laboratory environment up to the edge of space. To make use of these novel launch vehicles, the John Hopkins University Applied Physics Laboratory has established a Commercial Suborbital Program with a core system (JANUS) to support and enable many future suborbital missions. This program has already conducted six suborbital flight missions to establish vehicle interfaces and analyze the suitability and limits of each flight environment. Additionally, this program has also been selected by the NASA Flight Opportunities Program for five additional operational suborbital missions. Here we present the results of our completed missions as well as descriptions of future selected missions scheduled for 2021–2023.

Abstract

Nowadays, patients require the highest quality of treatment, but generally prefer to spend as little time as possible in the dental chair. Therefore, there is significant benefit for using new technologies such as CAD/CAM (computer aided design/computer aided manufacturing), which provides both quality and speed. There is an increase in ceramic materials and ceramic blocks/discs available, with varying properties. This has resulted in some confusion and difficulty in making an informed decision about which material is best for a specific clinical situation. The objective of this review is to provide an overview and comparison of basic mechanical properties of currently used CAD/CAM ceramic materials based on a review of the currently available literature.

Abstract

Usually, remote phosphor structures are beneficial in terms of flux but unfavorable in terms of color quality compared to conformal phosphor or in-cup phosphor packages. To eliminate this disadvantage, many studies have focused on increasing the chromatic quality of the remote phosphor configuration, which requires great efforts in improving two parameters of color: color rendering index (CRI) and color quality scale (CQS). CRI is known as the most useful quantitative method used to measure the ability of a light source to reproduce the colors of illuminated objects faithfully and naturally. Similarly, CQS is also a method of lighting quality determination and analysis, especially used as an alternative to the unsaturated CRI colors. In this paper, we proposed dual-layer remote phosphor structure as a novel method of CRI and CQS enhancement to improve WLEDs’ color quality. Five alike WLEDs but having different color temperatures in the range of 5600 K to 8500 K were applied in this study. The idea behind the study is to place a red phosphor layer SrwFxByOz:Eu2+,Sm2+ on the yellow phosphor layer YAG:Ce3+ and then determining an appropriate concentration of SrwFxByOz:Eu2+,Sm2+ added to achieve the highest color quality. The results point out that SrwFxByOz:Eu2+,Sm2+ brings great benefits to the improvement of CRI and CQS parameters. Specifically, the higher the SrwFxByOz:Eu2+,Sm2+ concentration results in the greater CRI and CQS, owning to the enriched red light components in the WLEDs. However, the flux has a tendency of dropping when SrwFxByOz:Eu2+,Sm2+ concentration rises excessively. This has been proved by using the Mie-scattering theory and the Lambert-Beer law. The results of this article are essential references for manufacturing WLEDs with higher chromatic quality.

Abstract

Good-quality semiorganic single crystals of bis(glycine) strontium dichloride trihydrate (GSC) were grown by slow evaporation technique. The lattice parameters of the grown crystal were verified through single crystal X-ray diffraction. Besides, the crystallinity of the material was analyzed with powder X-ray diffraction. The fingerprint of functional groups of this material was analyzed by FT-IR technique. The UV transparency cutoff wavelength of GSC was found to be 240 nm and the crystal exhibited 80 % transmission in the entire visible region. All intermolecular and intramolecular interactions of the grown crystal were interpreted by Hirshfeld surface analysis, and the strength of the interactions was graphically illustrated by fingerprint graphs. The intramolecular charge transfers of the crystal were assessed through frontier molecular orbital analysis.

Abstract

Cellulose nanocrystals were extracted from cotton. The cellulose nanocrystals made a self-assembly structure when dried under slow conditions, as it was revealed by the characterization made to the material. The AFM images of the nanocrystals showed that they had a changing local orientation, pointing in a preferred direction that underwent a periodic change. This periodic change resembles the orientation of a chiral nematic phase. The TEM images showed that the nanocrystals had a rod-like appearance with average length size of 98.5 nm and a diameter of 4.7 nm. The TEM characterization showed the nanocrystals with more details than AFM. In this paper, the self-assembling of CNC was observed by AFM, and further investigations were done by TEM, deconvoluting the process of CNC nanorods aggregation.

Abstract

The increasing availability of flights on suborbital rockets creates new avenues for the study of spaceflight effects on biological systems, particularly of the transitions between hypergravity and microgravity. This paper presents an initial comparison of the responses of Arabidopsis thaliana to suborbital and atmospheric parabolic flights as an important step toward characterizing these emerging suborbital platforms and their effects on biology. Transcriptomic profiling of the response of the Arabidopsis ecotype Wassilewskija (WS) to the aggregate suborbital spaceflight experiences in Blue Origin New Shepard and Virgin Galactic SpaceShipTwo revealed that the transcriptomic load induced by flight differed between the two flights, yet was biologically related to traditional parabolic flight responses. The sku5 skewing mutant and 14-3-3κ:GFP regulatory protein overexpression lines, flown in the Blue Origin and parabolic flights, respectively, each showed altered intra-platform responses compared to WS. An additional parabolic flight using the F-104 Starfighter showed that the response of 14-3-3κ:GFP to flight was modulated in a similar manner to the WS line. Despite the differing genotypes, experimental workflows, flight profiles, and platforms, differential gene expression linked to remodeling of central metabolic processes was commonly observed in the flight responses. However, the timing and directionality of differentially expressed genes involved in the conserved processes differed among the platforms. The processes included carbon and nitrogen metabolism, branched-chain amino acid degradation, and hypoxic responses. The data presented herein highlight the potential for various suborbital platforms to contribute insights into biological responses to spaceflight, and further suggest that in-flight fixation during suborbital experiments will enhance insights into responses during each phase of flight.

Abstract

This paper reports the synthesis and characterization of the Bi0:94Gd0:06FeO3 sample obtained by solid state reaction method. The structural and morphological analysis was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rietveld refinement analysis, confirming the obtaining of a rhombohedral crystalline phase and R3c space group (a = b = 5.577 Å and c = 13.847 Å), with an interconnected structure. Studies by X-ray photoelectron spectroscopy (XPS) revealed trivalent oxidation states of Bi, Fe and Gd ions. The synthesized sample exhibited a non-linear M–H loop indicating a weak ferromagnetic behavior with a remnant magnetization of 6.34 emu˙mol−1 and a coercive field of 295 Oe. The obtained structural and magnetic characteristics make these materials of great interest as multiferroic components.