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High-temperature stable \u3c0-phase-shifted fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask
No full textType II \u3c0-phase-shifted Bragg gratings stable up to ~1000\ub0C are written inside a standard single mode silica optical fiber (SMF-28) with infrared femtosecond pulses and a special phase mask. Inscription through the protective polyimide fiber coating is also demonstrated. The birefringence of the Bragg gratings and, as a result, the polarization dependence of their spectra are strongly affected by the femtosecond laser polarization. Using optimized writing conditions, the full width at half maximum of the \u3c0-phase-shifted passband feature can be ~30 pm in transmission, while the polarization-dependent shift of its central wavelength can be less than 8 pm, for a 7 mm long grating structure. This makes such gratings a unique tool for high-resolution measurements of temperature, load and vibration in extreme temperature environments.Peer reviewed: YesNRC publication: Ye
Novel type II Bragg grating structures in silica fibers using femtosecond lasers and phase masks
No full textThis review paper presents recent developments on the fabrication of novel thermally stable Type II fiber Bragg grating structures using femtosecond lasers and the phase mask technique. By manipulating the inscription beam and phase mask designs, exotic grating structures, such as ultrashort gratings < 100 \u3bcm in length, Fabry-Perot structures or \u3c0-phase shifted structures can be created that are stable at high temperatures. These novel structures can also be created directly through protective polymer coatings such as polyimide, thus simplifying their manufacture.Peer reviewed: YesNRC publication: Ye
Titanium dioxide: material for a sustainable environment
No full textTitanium dioxide is currently being used in many industrial products. It provides unique photocatalytic properties for water splitting and purification, bacterial inactivation, and organics degradation. It has also been widely used as the photoanode for dye-sensitized solar cells and coatings for self-cleaning surfaces, biomedical implants, and nanomedicine. This book covers various aspects of titanium dioxide nanomaterials including their unique one-dimensional, two-dimensional, mesoporous, and hierarchical nanostructures and their synthetic methods such as sol-gel, hydrothermal, anodic oxidation, and electrophoretic deposition, as well as its key applications in environmental and energy sectors. Through these 24 chapters written by experts from the international scientific community, readers will have access to a comprehensive overview of the recent research and development findings on the titanium dioxide nanomaterials.Peer reviewed: YesNRC publication: Ye
Camelid single-domain antibodies raised by DNA immunization are potent inhibitors of EGFR signaling
No full textUpregulation of epidermal growth factor receptor (EGFR) is a hallmark of many solid tumors, and inhibition of EGFR signaling by small molecules and antibodies has clear clinical benefit. Here, we report the isolation and functional characterization of novel camelid single-domain antibodies (sdAbs or VHHs) directed against human EGFR. The source of these VHHs was a llama immunized with cDNA encoding human EGFR ectodomain alone (no protein or cell boost), which is notable in that genetic immunization of large, outbred animals is generally poorly effective. The VHHs targeted multiple sites on the receptor's surface with high affinity ( KD range: 1-40 nM), including one epitope overlapping that of cetuximab, several epitopes conserved in the cynomolgus EGFR orthologue, and at least one epitope conserved in the mouse EGFR orthologue. Interestingly, despite their generation against human EGFR expressed from cDNA by llama cells in vivo (presumably in native conformation), the VHHs exhibited wide epitope-dependent variation in their apparent affinities for native EGFR displayed on tumor cell lines. As fusions to human IgG1 Fc, one of the VHH-Fcs inhibited EGFR signaling induced by EGF binding with a potency similar to that of cetuximab (IC50: ~30 nM). Thus, DNA immunization elicited high-affinity, functional sdAbs that were vastly superior to those previously isolated by our group through protein immunization.Peer reviewed: YesNRC publication: Ye
Investigation on the fatigue fracture characteristics between friction-stir welded aluminium overlap joints with different alloys and tools
No full textIn this study, overlap FSW joints were prepared using various aluminium alloys and tool shapes and tested in single-lap shear fatigue. Such configurations could be used in automotive applications. While all tests resulted in fracture by crack propagation through the upper sheet, performance differences appeared between alloys and tools. The objective is to understand the different fatigue strengths for a subset of aluminium alloys (5083SPF and 7075-T6) and tools (MX Triflute \uae and Flared Whisk Triflute \uae). The fatigue failure modes are investigated using a combination of experimental and numerical methods to establish process-microstructure-properties correlations, highlight key differences for the subset of alloys and tools under study, and identify favourable factors for fatigue performance.Peer reviewed: YesNRC publication: Ye
Software to determine sphere center from terrestrial laser scanner data per ASTM Standard E3125-17
No full textTerrestrial laser scanners (TLSs) are instruments that can measure 3D coordinates of objects at high speed using a laser, resulting in high density 3D point cloud data. The Dimensional Metrology Group (DMG) at NIST performed research to support the development of documentary standards within ASTM E57 committee on 3D imaging systems. This led to the publication of the ASTM E3125-2017 standard on point-to-point distance performance evaluation of 3D imaging systems such as TLSs. To ensure that the data from different TLS systems are processed identically, the ASTM E3125- 2017 mandates the use of a common algorithm to determine the center of a sphere from point cloud data. This paper describes this algorithm and software code is provided as a download.Peer reviewed: YesNRC publication: Ye
[INVITED] Subwavelength structures for silicon photonics biosensing
No full textSilicon photonic biosensors hold the potential for highly accurate, yet low cost point-of-care devices. Maximizing the sensitivity of the sensing chips while reducing the complexity and cost of the read-out system is pivotal to realize this potential. Here we present an extensive analysis, both from a practical and a theoretical perspective, of current biosensors, and analyze how subwavelength structures can be exploited to enhance their sensitivity. This study is not restricted just to the near-infrared band as we also determine the sensing capabilities of the suspended silicon waveguides with subwavelength metamaterial cladding working in the mid-infrared range. These waveguides have been recently proposed to cover the full transparency window of silicon (\u202f\u3bb<~8.5 \u3bcm), where the fingerprint spectral region of many molecules takes place and so a plethora of evanescent field absorption-based applications will be developed in the near future.Peer reviewed: YesNRC publication: Ye