Objective: The introduction of focused ion beam (FIB) milling has facilitated preparation of hard tissue samples for transmission electron microscope (TEM). However, this technique generates high temperature that may alter or damage morphological features in biological tissue. Therefore, the aim of this study was to determine the effects of cryogenic cooling on the morphological features of dentin interfaces with dental restorative materials in samples prepared by FIB for TEM examination.
Methods: After preparation of a cylindrical-shaped cavities in extracted, non-carious premolar teeth, the specimens were restored with dental adhesive/composite and categorized into two restorative materials groups; (PB) a combination of Clearfil Protect Bond (Kuraray Noritake Dental, Japan)/Estelite Sigma Quick composite (Tokuyama Dental, Japan), and (SB) Filtek Silorane restorative system (3M ESPE, USA). The specimens were subjected to interfacial cross-sectioning, followed by observation and area selection using confocal laser microscopy. Later, ultrathin sections were prepared using FIB with cryogenic cooling (PB-C) and (SB-C), or without cooling (PB-NC) and (SB-NC) that all were examined under TEM.
Results: Resulting TEM images of the ultra-morphological features at the resin-dentin nano-interaction zone were improved when FIB preparation was conducted in the cryogenic condition and no sign of artifacts were detected.
Significance: Conducting ion beam milling with cryogenic cooling was advantageous in minimizing the elevation in specimen temperature. This led to preservation of dentin microstructures that revealed additional information about substrates that are necessary for advanced characterization of tooth-biomaterial interactions.
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http://dx.doi.org/10.1016/j.dental.2015.04.010 | DOI Listing |
Rev Sci Instrum
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NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
This work describes the design and implementation of optics for EXCLAIM, the EXperiment for Cryogenic Large-Aperture Intensity Mapping. EXCLAIM is a balloon-borne telescope that will measure integrated line emission from carbon monoxide at redshifts z < 1 and ionized carbon ([CII]) at redshifts z = 2.5 - 3.
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January 2025
Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India.
Quantum technology exploits fragile quantum electronic phenomena whose energy scales demand ultra-low electron temperature operation. The lack of electron-phonon coupling at cryogenic temperatures makes cooling the electrons down to a few tens of millikelvin a non-trivial task, requiring extensive efforts on thermalization and filtering high-frequency noise. Existing techniques employ bulky and heavy cryogenic metal-powder filters, which prove ineffective at sub-GHz frequency regimes and unsuitable for high-density quantum circuits such as spin qubits.
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EXpressLO LLC, 5483 Lee St Unit 12, Lehigh Acres, FL 33971, USA.
A conduction heat transfer analysis of ex situ lift-out specimen handling under cryogenic conditions (cryo-EXLO) is performed and compared with experimentally determined temperature values using a type K thermocouple. Using a finite-volume solver for heat conduction, the analysis confirms that manipulation of a specimen by a probe above a working surface cooled at liquid nitrogen (LN2) temperatures can remain below the critical vitreous temperature up to several hundreds of micrometers above the working surface, allowing for ample distance for lift out and specimen manipulation. In addition, the temperature above the cryogenic shuttle sample holder working surface remains below the vitreous temperature for several tens of minutes without adding cryogen, yielding sufficient time to complete multiple manipulations.
View Article and Find Full Text PDFBio Protoc
January 2025
Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark.
Magnetic resonance imaging (MRI) is an invaluable method of choice for anatomical and functional in vivo imaging of the brain. Still, accurate delineation of the brain structures remains a crucial task of MR image evaluation. This study presents a novel analytical algorithm developed in MATLAB for the automatic segmentation of cerebrospinal fluid (CSF) spaces in preclinical non-contrast MR images of the mouse brain.
View Article and Find Full Text PDFLasers Surg Med
January 2025
Main Line Center for Laser Surgery, Ardmore, Pennsylvania, USA.
Background: Poikiloderma of Civatte is a benign skin condition characterized by reticulate erythema and hyperpigmentation in sun-exposed areas, predominantly on the neck, cheeks, and chest. Chronic UV exposure leads to vascular proliferation and red cell extravasation resulting in hemosiderin and melanin deposition. While many light-based modalities have been utilized to treat the disorder, the significant vascularity makes it ideally suited for treatment with vascular lasers.
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