Monday, 24 April 2017

NIH/NCI Grant Will Further Investigation of Breast Tumor Margin Assessment

The National Cancer Institute, part of the National Institutes of Health, has awarded a three-year, $424,081 grant to Magda El-Shenawee, electrical engineering professor, for her work on an intraoperative and rapid method of detecting positive cancer margins during conservative breast cancer surgery, or lumpectomy.
Standard medical imaging techniques insufficiently provide clear assessment of breast tissue margins, resulting in a reported second surgery rate of 20 to 40 percent.
The grant will allow El-Shenawee's research team to advance the assessment of breast tumor margins using new Terahertz imaging technology, which will provide the groundwork for fast, intraoperative tumor margin assessment and significantly reduce the occurrence of second surgeries, cancer reoccurrence and metastasis.

Investigators will image two types of tumor tissues. Pictured above, are samples of freshly excised tumors from mice.

Bowman demonstrates how images can be viewed using terahertz imaging.
"When we talk to any doctor about the tumor margins, they see issues," said El-Shenawee. "If they can't get all of the tumor in the first operation, two things can occur. Cancer can come back in the same spot, or the cancer can metastasize and spread to other organs. That is the danger of breast cancer."
Terahertz technology offers high, sub-millimeter resolution, as well as sensitivity to water content, which can be a major contrast factor in biological tissues. The researchers will focus their efforts on imaging two types of tumor tissues - one developed from phantom tissues that mimic freshly excised human tumors and the other freshly excised tumors grown in mice.
"We believe this new Terahertz technology will give us better images of the tissue than current, standard methods," El-Shenawee said.
El-Shenawee will collaborate with University of Arkansas professors Narasimhan Rajaram, assistant professor of biomedical engineering; Jingxian Wu, associate professor of electrical engineering, Avishek Chakraborty, assistant professor of mathematical sciences; and Tyler Bowman, doctoral student in electrical engineering. Bowman is an NSF Graduate Fellow and University of Arkansas Distinguished Doctoral Fellow. El-Shenawee will also collaborate with Keith Bailey, director of the Oklahoma Animal Disease Diagnostic Laboratory at Oklahoma State University; and with Lucas Campbell, M.D., pathologist at Northwest Arkansas Pathology Associates in Fayetteville.

CONTACTS
Magda El-Shenawee, professor 
Department of Electrical Engineering 
479-575-4037, magda@uark.edu
Matt McGowan, science and research communications officer 
University Relations 
479-575-4246, dmcgowa@uark.edu
Sierra Mendoza, administrative specialist 
Department of Electrical Engineering 
479-575-3005, smendoza@uark.edu
also see
http://www.azom.com/suppliers.aspx?SupplierID=12145

Terahertz Superresolution Stratigraphic Characterization of Multilayered Structures Using Sparse Deconvolution


Dong, J., Wu, X., Locquet, A., & Citrin, D. S. (2017). Terahertz Superresolution Stratigraphic Characterization of Multilayered Structures Using Sparse Deconvolution. IEEE Transactions on Terahertz Science and Technology.

Image result for david citrin terahertzAbstract:
Terahertz sparse deconvolution based on an iterative shrinkage algorithm is presented in this study to characterize multilayered structures. With an upsampling approach, sparse deconvolution with superresolution is developed to overcome the time resolution limited by the sampling period in the measurement and increase the precision of the estimation of echo arrival times. A simple but effective time-domain model for describing the temporal pulse spreading due to the frequency-dependent loss is also designed and introduced into the algorithm, which greatly improves the performance of sparse deconvolution in processing time-varying pulses during the propagation of terahertz waves in materials. Numerical simulations and experimental measurements verify the algorithms and show that sparse deconvolution can be considered as an effective tool for terahertz nondestructive characterization of multilayered structures.
For full paper see http://ieeexplore.ieee.org/abstract/document/7874211/
... A standard THz time-domain spectroscopy system (Teraview TPS Spectra 3000) is employed in this study to perform THz reflective imaging at almost normal incidence on these two samples.......
For more information see https://www.ece.gatech.edu/faculty-staff-directory/david-s-citrin
For more information about  TeraView see http://www.azom.com/suppliers.aspx?SupplierID=12145

Mathematical Modelling of Liquid Transport in Swelling Pharmaceutical Immediate Release Tablets

Markl, D., Yassin, S., Wilson, D. I., Goodwin, D. J., Anderson, A., & Zeitler, J. A. (2017). Mathematical Modelling of Liquid Transport in Swelling Pharmaceutical Immediate Release Tablets. International Journal of Pharmaceutics.

Abstract


Oral dosage forms are an integral part of modern health care and account for the majority of drug delivery systems. Traditionally the analysis of the dissolution behaviour of a dosage form is used as the key parameter to assess the performance of a drug product. However, understanding the mechanisms of disintegration is of critical importance to improve the quality of drug delivery systems. The disintegration performance is primarily impacted by the hydration and subsequent swelling of the powder compact. Here we compare liquid ingress and swelling data obtained using terahertz pulsed imaging (TPI) to a set of mathematical models. The interlink between hydration kinetics and swelling is described by a model based on Darcy's law and a modified swelling model based on that of Schott. Our new model includes the evolution of porosity, pore size and permeability as a function of hydration time. Results obtained from two sets of samples prepared from pure micro-crystalline cellulose (MCC) indicate a clear difference in hydration and swelling for samples of different porosities and particle sizes, which are captured by the model. Coupling a novel imaging technique, such as TPI, and mathematical models allows better understanding of hydration and swelling and eventually tablet disintegration.

for full paper see 
http://www.sciencedirect.com/science/article/pii/S037851731730296X

for information about TeraView see
http://www.azom.com/suppliers.aspx?SupplierID=12145

for information about the Cambridge Terahertz group see
http://thz.ceb.cam.ac.uk/

Sunday, 23 April 2017

Intermolecular anharmonicity in molecular crystals: interplay between experimental low-frequency dynamics and quantum quasi-harmonic simulations of solid purine

Ruggiero, Michael T., J. Axel Zeitler, and Alessandro Erba. "Intermolecular anharmonicity in molecular crystals: interplay between experimental low-frequency dynamics and quantum quasi-harmonic simulations of solid purine." Chemical Communications (2017).


Abstract

Image result for axel terahertzThe intermolecular anharmonic potential of crystalline purine is probed by means of temperature-dependent terahertz time-domain spectroscopy, low-frequency Raman scattering, X-ray diffraction, and ab initio quasi-harmonic quantum-chemical simulations. As temperature increases, anharmonicity in the intermolecular interactions results in strongly anisotropic thermal expansion – with a negative thermal expansion along the b crystallographic axis – yielding corresponding bulk structural modifications. The observed thermally-induced shifts of most vibrational bands in the terahertz region of the spectra are shown to arise from volume-dependent thermal changes of the hydrogen-bond pattern along the a and b crystallographic axes.

Dr Zeilter's group uses a TeraPulse 4000 for more information see http://www.azom.com/equipment-details.aspx?EquipID=4411

Friday, 21 April 2017

Non-contact paint thickness measurement system for industrial deployment




Abstract
We present a non-contact, multi-layer coating thickness sensor based on the use of pulsed terahertz light.
The coated surface is illuminated from a short distance with a terahertz light pulse. The reflected signal, containing reflections at the interface of adjacent coating layers, is analysed to determine the thickness of each layer.
The unit has been designed and tested for deployment in manufacturing environments and is available in both manual and automated (robotic) forms.
Being non-contact, it offers significant advantages over existing technologies: for example, line scans and measurement of curved surfaces, including windshield flanges.
The system has been tested by a number of automobile manufacturers. Summary results of trials are discussed.
For more information see http://dsctfocus.org/
Also, see http://www.azom.com/article.aspx?ArticleID=13544

Terahertz Imaging of Three-Dimensional Dehydrated Breast Cancer Tumors

T. Bowman, Y. Wu, J. Gauch, L. K. Campbell, and M. El-Shenawee

Bowman, T., Wu, Y., Gauch, J. et al. J Infrared Milli Terahz Waves (2017) 38: 766. doi:10.1007/s10762-017-0377-y

Abstract
Professor Magda El-Shenawee and graduate assistant, Tyler Bowman, use THz imaging technology to assess the margins of cancerous breast tumors.
This work presents the application of terahertz imaging to three-dimensional formalin-fixed, paraffin-embedded human breast cancer tumors. The results demonstrate the capability of terahertz for in-depth scanning to produce cross section images without the need to slice the tumor. Samples of tumors excised from women diagnosed with infiltrating ductal carcinoma and lobular carcinoma are investigated using a pulsed terahertz time domain imaging system. A time of flight estimation is used to obtain vertical and horizontal cross section images of tumor tissues embedded in paraffin block. Strong agreement is shown comparing the terahertz images obtained by electronically scanning the tumor in-depth in comparison with histopathology images. The detection of cancer tissue inside the block is found to be accurate to depths over 1 mm. Image processing techniques are applied to provide improved contrast and automation of the obtained terahertz images. In particular, unsharp masking and edge detection methods are found to be most effective for three-dimensional block imaging.

For more information about Professor El-Shenawee see http://terahertz.uark.edu/

For more information about TeraView visit www.teraview.com

Friday, 27 January 2017

TeraView to present results from pharmaceutical studies at this year’s Photonics West

TeraView's Dr Philip Taday will be presenting a talk entitled 'Using terahertz-pulsed imaging (TPI) to study osmotic tablets' at this years SPIE Photonics West conference. The event will take place at The Moscone Center, San Francisco, California, USA.

The conference runs from 28th January until 2nd February 2017. TeraView will be presenting their talk on Tuesday 31 January, 10:30 - 12:20 pm (Room 270).

More details on the conference can be found here.

Wednesday, 18 January 2017

Contrast in Terahertz Images of Archival Documents—Part I: Influence of the Optical Parameters from the Ink and Support

Tiphaine Bardon ; Robert K. May ; J. Bianca Jackson ; Gabriëlle Beentjes ; Gerrit de Bruin ; Philip F. Taday ; Matija Strlič


Abstract:

This study aims to objectively inform curators when terahertz time-domain (TD) imaging set in reflection mode is likely to give well-contrasted images of inscriptions in a complex archival document and is a useful non-invasive alternative to current digitisation processes. To this end, the dispersive refractive indices and absorption coefficients from various archival materials are assessed and their influence on contrast in terahertz images from historical documents is explored. Sepia ink and inks produced with bistre or verdigris mixed with a solution of Arabic gum or rabbit skin glue are unlikely to lead to well-contrasted images. However, dispersions of bone black, ivory black, iron gall ink, malachite, lapis lazuli, minium and vermilion are likely to lead to well-contrasted images. Inscriptions written with lamp black, carbon black and graphite give the best imaging results. The characteristic spectral signatures from iron gall ink, minium and vermilion pellets between 5 and 100 cm−1 relate to a ringing effect at late collection times in TD waveforms transmitted through these pellets. The same ringing effect can be probed in waveforms reflected from iron gall, minium and vermilion ink deposits at the surface of a document. Since TD waveforms collected for each scanning pixel can be Fourier-transformed into spectral information, terahertz TD imaging in reflection mode can serve as a hyperspectral imaging tool. However, chemical recognition and mapping of the ink is currently limited by the fact that the morphology of the document influences more the terahertz spectral response of the document than the resonant behaviour of the ink.

Full article here.


Wednesday, 11 January 2017

Preparation, characterization, Raman, and terahertz spectroscopy study on carbon nanotubes, graphene nano-sheets, and onion like carbon materials

A. Abouelsayed ; Badawi Anis ; Safwat Hassaballa ; Ahmed S.G. Khalil ; Usama M. Rashed ; Kamal A. Eid ; Emad Al-Ashkar ; W. El hotaby


Abstract:

We present the optical properties of carbon nanotubes, graphene nanosheets, and onion like carbon (OLC) samples with different cages size in wide frequency range from 0.06 to 1650 THz. The samples were characterized by high resolution transmission electron microscope (HRTEM), Raman, and UV–Vis-IR-THz spectroscopy. The broad absorption bands centered at around 10, 3, 2.5, 1.5, and 1.8 THz for SWCNTs, MWCNTs, graphene nanosheets, large cages (OLC1), and small cages (OLC2) samples, respectively, are assigned to plasmon resonance due to the localization of free carriers in a finite length. For SWCNTs, both the plasmon band position and the Drude weight (D) are located at higher values as compared with MWCNTs, graphene nanosheets, and OLC sample, suggesting that the dimensionality of the system plays a major role regarding the carrier mobility of the graphene structure. The differences in the estimated values of D, the Fermi energy (Ef), and density of carriers (N) in case of OLC samples can be due to the variation in sizes of the cages and the variation of the defects in the structure of the outermost layers of cages, where each cages consist of multi-layers of graphene enclosed one into another.

Full article available here.