Abstract
Results of a theoretical and experimental investigation of THz detection
of randomly-oriented metal particles smaller than 1 mm embedded in
pressboard are reported and critically compared with X-ray scanner
results. A theoretical description based on Gaussian beam theory and a
transfer function approach enabled simulation of signals transmitted
around and reflected from real particles and was able to predict signal
detectability. Simulated signals and detection limits were compared with
experimental transmission and reflection time domain spectroscopy (TDS)
raster scanning data. Simulated and measured pulse amplitude and shape
were in agreement. Reflection mode was superior to transmission mode in
terms of both particle visibility and hit ratio. Imaging of particles
was also possible in “reflection in transmission” mode, which can be
used to complement classical transmission mode. X-ray images did not
detect the smallest particles sufficiently and, therefore, could not be
used as reference data for comparison with THz data. The results
demonstrate that TDS reflection scanning is able to determine the
position of small metal particles and the technique could be possibly
used for quality control of pressboard insulation.
Read full article here
Tuesday, 5 January 2016
Sunday, 3 January 2016
Norfloxacin-loaded collagen/chitosan scaffold for skin reconstruction: Preparation, evaluation and in-vivo wound healing assessment
Abstract
Biomaterial scaffolds are versatile tools as drug carrier for treatment of wounds. A series of norfloxacin-loaded scaffolds were synthesized for treatment of wounds by combining collagen with two different types of chitosan using freeze-drying technique. Subsequently, scaffolds were screened in terms of morphology, water absorption and retention capacity, biodegradation, ex-vivo bioadhesive strength, in-vitro drug release biological compatibility, x-ray diffractometry, differential scanning calorimetry as well as in-vivo evaluation. The results indicate that the scaffold mechanical strength is dependent on the type of used chitosan. The prepared scaffolds contained interconnected porous architecture. The scaffolds had high water uptake and retention capacity with extended biodegradation rate. Scaffolds prepared with chitosan HCl showed superior bioadhesive strength compared to those prepared with low molecular weight chitosan. All scaffolds showed almost 100% drug release within 24 hours. As identified by the terahertz pulsed imaging measurements, there is single scaffold area with the same concentration. After 28 days of wound dressing with selected norfoloxacin-loaded or unloaded collagen/chitosan scaffolds in Albino rats, it was found that the tissue regeneration time was fast compared to non-treated wounds. Furthermore, the drug-loaded scaffolds showed normal structure of an intact epidermal layer as well as the underlying dermis as revealed by histopathological studies. The obtained results suggest that the investigated norfloxacin-loaded collagen/chitosan scaffold is a potential candidate for skin regeneration application.
Full article available here
Biomaterial scaffolds are versatile tools as drug carrier for treatment of wounds. A series of norfloxacin-loaded scaffolds were synthesized for treatment of wounds by combining collagen with two different types of chitosan using freeze-drying technique. Subsequently, scaffolds were screened in terms of morphology, water absorption and retention capacity, biodegradation, ex-vivo bioadhesive strength, in-vitro drug release biological compatibility, x-ray diffractometry, differential scanning calorimetry as well as in-vivo evaluation. The results indicate that the scaffold mechanical strength is dependent on the type of used chitosan. The prepared scaffolds contained interconnected porous architecture. The scaffolds had high water uptake and retention capacity with extended biodegradation rate. Scaffolds prepared with chitosan HCl showed superior bioadhesive strength compared to those prepared with low molecular weight chitosan. All scaffolds showed almost 100% drug release within 24 hours. As identified by the terahertz pulsed imaging measurements, there is single scaffold area with the same concentration. After 28 days of wound dressing with selected norfoloxacin-loaded or unloaded collagen/chitosan scaffolds in Albino rats, it was found that the tissue regeneration time was fast compared to non-treated wounds. Furthermore, the drug-loaded scaffolds showed normal structure of an intact epidermal layer as well as the underlying dermis as revealed by histopathological studies. The obtained results suggest that the investigated norfloxacin-loaded collagen/chitosan scaffold is a potential candidate for skin regeneration application.
Full article available here
Equivalent circuit for VO2 phase change material film in reconfigurable frequency selective surfaces
Abstract
We developed equivalent circuits of phase change materials based on vanadium dioxide (VO2) thin films. These circuits are used to model VO2thin films for reconfigurable frequency selective surfaces (FSSs). This is important as it provides a way for designing complex structures. A reconfigurable FSS filter using VO2 ON/OFF switches is designed demonstrating −60 dB isolation between the states. This filter is used to provide the transmission and reflection responses of the FSS in the frequency range of 0.1–0.6 THz. The comparison between equivalent circuit and full-wave simulation shows excellent agreement.
Read full article here
We developed equivalent circuits of phase change materials based on vanadium dioxide (VO2) thin films. These circuits are used to model VO2thin films for reconfigurable frequency selective surfaces (FSSs). This is important as it provides a way for designing complex structures. A reconfigurable FSS filter using VO2 ON/OFF switches is designed demonstrating −60 dB isolation between the states. This filter is used to provide the transmission and reflection responses of the FSS in the frequency range of 0.1–0.6 THz. The comparison between equivalent circuit and full-wave simulation shows excellent agreement.
Read full article here
Monday, 14 December 2015
OTST 2017 to be held in London
The seventh international conference on Optical Terahertz Science and Technology (OTST 2017) will bring researchers from around the world to present and discuss most recent advances in terahertz (THz) research, ranging from fundamental science to cutting edge developments in THz technology. For the first time the conference will be held in Europe in the heart of London following the previous six conferences held in USA and Japan. An introductory workshop/tutorial for students and those who are new to the field of THz science and technology will be organised on the first day (April 2).
Organised by the IOP Instrument Science and Technology Group
Conference Chairs:
Dr Oleg Mitrofanov - University College London
Dr Miriam Serena Vitiello - NEST, Istituto Nanoscience CNR and Scuola Normale Superiore, Italy
Link
Tuesday, 8 December 2015
Terahertz session at CLEO 2016
Invited speakers at the terahertz session at CLEO 2016
S&I 5: Terahertz Technologies and Applications
Tyler Cocker, Univ. of Regensburg, Germany
Taking sub-cycle THz nanoscopy to the Limits
Michael Johnston, Univ. of Oxford, UK
Understanding Charge Dynamics in Perovskite Semiconductors using Non-contact THz Probes
Jaime Gomez Rivas, Dutch Institute for Fundamental Energy Research (DIFFER); Eindhoven Univ. of Tech, The Netherlands, Netherlands
THz metamaterials and metasurfaces
Miriam Vitiello, Scuola Normale Superiore di Pisa, Italy
Efficient Room-tempareture Terahertz Nano-detectors based on Novel 2D Materials
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