Geometrical Dependence on the Onset of Surface Plasmon Polaritons in THz Grid Metasurfaces

Abstract The transmission response of metallo-dielectric grid metasurfaces is experimentally investigated through Terahertz Time Domain Spectroscopy and the corresponding effective dielectric function is retrieved. Using a lumped element model we can determine the dependence of the effective plasma frequency (the transition frequency) on the metasurface filling factor F. The change of the transition frequency vs. F spans over one order of magnitude and sets the threshold between the metamaterial (homogeneous) and the photonic crystal (diffraction-like) regime, ruling the onset of two different Surface Plasmon Polaritons, spoof and high order. Field symmetry and spatial extension of such excitations are investigated for the possible applications of THz grid metasurfaces in bio- and chemical sensing and sub-wavelength imaging

Encoded-enhancement of THZ metasurface figure of merit for label-free sensing

We describe an experimental strategy for the use of Terahertz (THz) metasurfaces as a platform for label-free wide range detection of the dielectric function in biological fluids. Specifically, we propose a metagrid (MG), opportunely infiltrated with a fluid and then capped, as the reference structure for sensing experiments with a high reproducibility character. By combining experiments and full-wave simulations of the transmission T of such a structure, we introduce a reliable set up where the volume of the involved analyte in each unit cell is precisely determined. The unavoidable decrease in the quality factor of the intrinsic resonances due to the lossy fluid and cap layer is circumvented using an appropriate transformation of T that amplifies the change in the MG intrinsic resonances, improving in such a way the sensor sensitivity to values close to the experimental limits. The transformed signal features delta-like peaks enabling an easy readout of frequency positions at resonances

Effective EMI shielding behaviour of thin graphene/PMMA nanolaminates in the THz range

The use of graphene in a form of discontinuous flakes in polymer composites limits the full exploitation of the unique properties of graphene, thus requiring high filler loadings for achieving- for example- satisfactory electrical and mechanical properties. Herein centimetre-scale CVD graphene/polymer nanolaminates have been produced by using an iterative ‘lift-off/float-on’ process and have been found to outperform, for the same graphene content, state-of-the-art flake-based graphene polymer composites in terms of mechanical reinforcement and electrical properties. Most importantly these thin laminate materials show a high electromagnetic interference (EMI) shielding effectiveness, reaching 60 dB for a small thickness of 33 μm, and an absolute EMI shielding effectiveness close to 3·105 dB cm2 g−1 which is amongst the highest values for synthetic, non-metallic materials produced to date

Use of Integrated SPECT/CT Imaging for Tumor Dosimetry in I-131 Radioimmunotherapy: A Pilot Patient Study

Abstract Integrated systems combining functional (single-photon emission computed tomography; SPECT) imaging with anatomic (computed tomography; CT) imaging have the potential to greatly improve the accuracy of dose estimation in radionuclide therapy. In this article, we present the methodology for highly patient-specific tumor dosimetry by utilizing such a system and apply it to a pilot study of 4 follicular lymphoma patients treated with I-131 tositumomab. SPECT quantification included three-dimensional ordered-subset expectation-maximization reconstruction and CT-defined tumor outlines at each time point. SPECT/CT images from multiple time points were coupled to a Monte Carlo algorithm to calculate a mean tumor dose that incorporated measured changes in tumor volume. The tumor shrinkage, defined as the difference between volumes drawn on the first and last CT scan (a typical time period of 15 days) was in the range 5%-49%. The therapy-delivered mean tumor-absorbed dose was in the range 146-334cGy. For comparison, the therapy dose was also calculated by assuming a static volume from the initial CT and was found to underestimate this dose by up to 47%. The agreement between tracer-predicted and therapy-delivered tumor-absorbed dose was in the range 7%-21%. In summary, malignant lymphomas can have dramatic tumor regression within days of treatment, and advanced imaging methods allow for a highly patient-specific tumor-dosimetry calculation that accounts for this regression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78152/1/cbr.2008.0568.pd

Perspective of turkish medicine students on cancer, cancer treatments, palliative care, and oncologists (ares study): A study of the palliative care working committee of the turkish oncology group (TOG)

Cancer is one of the most common causes of death all over the World (Rahib et al. in Cancer Res 74(11):2913–2921, 2014; Silbermann et al. in Ann Oncol 23(Suppl 3):iii15–iii28, 2012). It is crucial to diagnose this disease early by effective screening methods and also it is very important to acknowledge the community on various aspects of this disease such as the treatment methods and palliative care. Not only the oncologists but every medical doctor should be educated well in dealing with cancer patients. Previous studies suggested various opinions on the level of oncology education in medical schools (Pavlidis et al. in Ann Oncol 16(5):840–841, 2005). In this study, the perspectives of medical students on cancer, its treatment, palliative care, and the oncologists were analyzed in relation to their educational status. A multicenter survey analysis was performed on a total of 4224 medical school students that accepted to enter this study in Turkey. After the questions about the demographical characteristics of the students, their perspectives on the definition, diagnosis, screening, and treatment methods of cancer and their way of understanding metastatic disease as well as palliative care were analyzed. The questionnaire includes questions with answers and a scoring system of Likert type 5 (absolutely disagree = 1, completely agree = 5). In the last part of the questionnaire, there were some words to detect what the words “cancer” and “oncologist” meant for the students. The participant students were analyzed in two study groups; “group 1” (n = 1.255) were phases I and II students that had never attended an oncology lesson, and “group 2” (n = 2.969) were phases III to VI students that had attended oncology lessons in the medical school. SPSS v17 was used for the database and statistical analyses. A value of p < 0.05 was noted as statistically significant. Group 1 defined cancer as a contagious disease (p = 0.00025), they believed that early diagnosis was never possible (p = 0.042), all people with a diagnosis of cancer would certainly die (p = 0.044), and chemotherapy was not successful in a metastatic disease (p = 0.003) as compared to group 2. The rate of the students that believed gastric cancer screening was a part of the national screening policy was significantly more in group 1 than in group 2 (p = 0.00014). Group 2 had a higher anxiety level for themselves or their family members to become a cancer patient. Most of the students in both groups defined medical oncologists as warriors (57% in group 1 and 40% in group 2; p = 0.097), and cancer was reminding them of “death” (54% in group 1 and 48% in group 2; p = 0.102). This study suggested that oncology education was useful for the students’ understanding of cancer and related issues; however, the level of oncology education should be improved in medical schools in Turkey. This would be helpful for medical doctors to cope with many aspects of cancer as a major health care problem in this country. © 2018, American Association for Cancer Education

Management and prognostic factors of recurrent pleomorphic adenoma of the parotid gland: personal experience and review of the literature

The aim of this study was to investigate the management and prognostic determinants of recurrent pleomorphic adenoma (RPA). A retrospective analysis was performed to examine the clinical features, the prevalence of surgical complications, and new recurrences of RPA. Tumor recurrence rate was estimated by the Kaplan–Meier method, and the prognostic value of some of the variables was tested by univariate analysis using the log rank test. The study focused on 33 patients, 18 female (54.5%) and 15 male (45.5%), aged 12–71 years (median 41). A total or extended total parotidectomy was performed in 16 cases (48.5%), a superficial parotidectomy in 10 cases (30.3%), and a local excision in 7 cases (21.2%). In ten patients (30.3%), a branch or the trunk of the facial nerve was deliberately sacrificed. Major complications included one unexpected definitive paralysis of the marginal mandibular branch of the facial nerve and 14 cases of Frey syndrome. Follow-up varied from 2 to 25 years (median 10.5 years), and there were 11 new recurrences (33.3%) within a period varying from 1 to 16 years (median 6 years). The estimated tumor recurrence rates were 14.1 ± 6.6% at 5 years, 31.4 ± 9.4% at 10 years, 43.0 ± 10.8% at 15 years, and 57.2 ± 14.8% at 20 years. Presence of a multinodular lesion and the type of intervention performed were significantly associated with a higher probability of recurrence. RPAs are prone to new recurrences, especially when multinodular and treated with a local excision. Surgical treatment should include facial nerve resection in selected cases. Follow-up for the patient’s lifetime is warranted

Brixsino High-Flux Dual X-Ray and THz Radiation Source Based on Energy Recovery Linacs

We present the conceptual design of a compact light source named BriXSinO. BriXSinO was born as demonstrator of the Marix project, but it is also a dual high flux radiation source Inverse Compton Source (ICS) of X-ray and Free-Electron Laser of THz spectral range radiation conceived for medical applications and general applied research. The accelerator is a push-pull CW-SC Energy Recovery Linac (ERL) based on superconducting cavities technology and allows to sustain MW-class beam power with almost just one hundred kW active power dissipation/consumption. ICS line produces 33 keV monochromatic X-Rays via Compton scattering of the electron beam with a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz. The THz FEL oscillator is based on an undulator imbedded in optical cavity and generates THz wavelengths from 15 to 50 micron