145 research outputs found
Plasmon Injection to Compensate and Control Losses in Negative Index Metamaterials
Metamaterials have introduced a whole new world of unusual materials with
functionalities that cannot be attained in naturally occurring material systems
by mimicking and controlling the natural phenomena at subwavelength scales.
However, the inherent absorption losses pose fundamental challenge to the most
fascinating applications of metamaterials. Based on a novel plasmon injection
(PI or \Pi) scheme, we propose a coherent optical amplification technique to
compensate losses in metamaterials. Although the proof of concept device here
operates under normal incidence only, our proposed scheme can be generalized to
arbitrary form of incident waves. The \Pi-scheme is fundamentally different
than major optical amplification schemes. It does not require gain medium,
interaction with phonons, or any nonlinear medium. The \Pi-scheme allows for
loss-free metamaterials. It is ideally suited for mitigating losses in
metamaterials operating in the visible spectrum and is scalable to other
optical frequencies. These findings open the possibility of reviving the early
dreams of making 'magical' metamaterials from scratch.Comment: Main text, 8 pages with 4 figures; supplemental material, 21 pages
with 21 figure
New subclasses of bi-univalent functions of complex order associated with hypergeometric functions
In the present paper, new subclasses of bi-univalent functions of complex order associated with hypergeometric functions are introduced and coefficient estimates for functions in these classes are obtained. Several new (or known) consequences of the results are also pointed out.Publisher's Versio
Antimicrobial activity of some endemic plant species from Turkey
Six plant extracts obtained from different parts such as the leaves, flowers and seeds of four species of the endemic plants in Turkey were tested on a total of 14 microorganisms, 10 of which were bacterialstrains and 4 yeast strains. Verbascum eriocarpum (flower) extract was found to be effective against Staphylococcus aureus; Stachys cretica subsp. anatolica (leaf and flower) and Heracleum paphlagonicum(seed) extracts were found to be effective against Bacillus subtilis; and Alcea apterocarpa (seed and sepal) extract was found to be effective against Pseudomonas aeruginosa. No antimicrobial activitywas observed in Heracleum paphlagonicum (leaf) and Alcea apterocarpa (leaf) plant extracts. The minimum inhibitory concentration (MIC) values of the plant extracts were calculated to be between 0.859 mg/ml and 110.5 mg/ml and the minimum bacteriocidal concentration (MBC) values were calculated to be between 3.44 mg/ml and 132 mg/ml
Computation of the resonant frequency of electrically thin and thick rectangular microstrip antennas with the use of fuzzy inference systems
A new method for calculating the resonant frequency of electrically thin and thick rectangular microstrip antennas, based on the fuzzy inference systems, is presented. The optimum design parameters of the fuzzy inference systems are determined by using the classical, modified, and improved tabu search algorithms. The calculated resonant frequency results are in very good agreement with the experimental results reported elsewhere
A Rare Novel Deletion of the Tyrosine Hydroxylase Gene in Parkinson Disease
Tyrosine hydroxylase (TH) enzyme is a rate limiting enzyme in dopamine biosynthesis. Missense mutation in both alleles of the TH gene is known to cause dopamine-related phenotypes, including dystonia and infantile Parkinsonism. However, it is not clear if single allele mutation in TH modifies the susceptibility to the adult form of Parkinson disease (PD). We reported a novel deletion of entire TH gene in an adult with PD. The deletion was first identified by copy number variation (CNV) analysis in a genome-wide association study using Illumina Infinium BeadChips. After screening 635 cases and 642 controls, the deletion was found in one PD case but not in any control. The deletion was confirmed by multiple quantitative PCR (qPCR) assays. There is no additional exonic single nucleotide variant in the one copy of TH gene of the patient. The patient has an age-at-onset of 54 years, no evidence for dystonia, and was responsive to L-DOPA. This case supports the importance of the TH gene in PD pathogenesis and raises more attention to rare variants in candidate genes being a risk factor for Parkinson disease. © 2010 Wiley-Liss, Inc
Active control of a plasmonic metamaterial for quantum state engineering
We experimentally demonstrate the active control of a plasmonic metamaterial
operating in the quantum regime. A two-dimensional metamaterial consisting of
unit cells made from gold nanorods is investigated. Using an external laser we
control the temperature of the metamaterial and carry out quantum process
tomography on single-photon polarization-encoded qubits sent through,
characterizing the metamaterial as a variable quantum channel. The overall
polarization response can be tuned by up to 33% for particular nanorod
dimensions. To explain the results, we develop a theoretical model and find
that the experimental results match the predicted behavior well. This work goes
beyond the use of simple passive quantum plasmonic systems and shows that
external control of plasmonic elements enables a flexible device that can be
used for quantum state engineering.Comment: 8 pages, 4 figure
Video-Based Hand Movement Analysis of Parkinson Patients before and after Medication Using High-Frame-Rate Videos and MediaPipe
Tremor is one of the common symptoms of Parkinson’s disease (PD). Thanks to the recent evolution of digital technologies, monitoring of PD patients’ hand movements employing contactless methods gained momentum. Objective: We aimed to quantitatively assess hand movements in patients suffering from PD using the artificial intelligence (AI)-based hand-tracking technologies of MediaPipe. Method: High-frame-rate videos and accelerometer data were recorded from 11 PD patients, two of whom showed classical Parkinsonian-type tremor. In the OFF-state and 30 Minutes after taking their standard oral medication (ON-state), video recordings were obtained. First, we investigated the frequency and amplitude relationship between the video and accelerometer data. Then, we focused on quantifying the effect of taking standard oral treatments. Results: The data extracted from the video correlated well with the accelerometer-based measurement system. Our video-based approach identified the tremor frequency with a small error rate (mean absolute error 0.229 (±0.174) Hz) and an amplitude with a high correlation. The frequency and amplitude of the hand movement before and after medication in PD patients undergoing medication differ. PD Patients experienced a decrease in the mean value for frequency from 2.012 (±1.385) Hz to 1.526 (±1.007) Hz and in the mean value for amplitude from 8.167 (±15.687) a.u. to 4.033 (±5.671) a.u. Conclusions: Our work achieved an automatic estimation of the movement frequency, including the tremor frequency with a low error rate, and to the best of our knowledge, this is the first paper that presents automated tremor analysis before/after medication in PD, in particular using high-frame-rate video data
Full-wave modeling of broadband near field scanning microwave microscopy
The authors would like to thank professor Dr. Gabriel Gomila from Institut de Bioenginyeria de Catalunya
(IBEC) and Universitat de Barcelona for the fruitful discussion and support, as well as to Dr. Georg Gramse from
Johannes Kepler University Linz for the experimental data. B.W. thanks the funding from the China Scholarship
Council (CSC) for the support of his research at Queen Mary University of London, UK. Y.H. would like to thank
EU-FP7 Nanomicrowave project for the financial support
Effects of web-based electrocardiography simulation on strategies and learning styles
Objective: To identify the association between the use of web simulation electrocardiography and the learning approaches, strategies and styles of nursing degree students. Method: A descriptive and correlational design with a one-group pretest– posttest measurement was used. The study sample included 246 students in a Basic and Advanced Cardiac Life Support nursing class of nursing degree. Results: No significant differences between genders were found in any dimension of learning styles and approaches to learning. After the introduction of web simulation electrocardiography, significant differences were found in some item scores of learning styles: theorist (p < 0.040), pragmatic (p < 0.010) and approaches to learning. Conclusion: The use of a web electrocardiogram (ECG) simulation is associated with the development of active and reflexive learning styles, improving motivation and a deep approach in nursing students
Geriatric oncology: comparing health related quality of life in head and neck cancer patients
Background: Population ageing is increasing the number of people annually diagnosed with cancer worldwide, once most types of tumours are age-dependent. High-quality healthcare in geriatric oncology requires a multimodal approach and should take into account stratified patient outcomes based on factors other than chronological age in order to develop interventions able to optimize oncology care. This study aims to evaluate the Health Related Quality of Life in head and neck cancer patients and compare the scores in geriatric and younger patients. Methods. Two hundred and eighty nine head and neck cancer patients from the Oncology Portuguese Institute participated in the Health Related Quality of Life assessment. Two patient groups were considered: the geriatric ( 65 years old, n = 115) and the younger (45-60 years old, n= 174). The EORTC QLQ-C30 and EORTC QLQ-H&N35 questionnaires were used. Results: Head and neck cancer patients were mostly males, 77.4% within geriatric group and 91.4% among younger patients group. The most frequent tumour locations were similar in both groups: larynx, oral cavity and oropharynx - base of the tongue. At the time of diagnosis, most of younger male patients were at disease stage III/IV (55.9%) whereas the majority of younger female patients were at disease stage I/II (83.4%). The geriatric patient distribution was found to be similar in any of the four disease stages and no gender differences were observed. We found that age (geriatrics scored generally worse), gender (females scored generally worse), and tumour site (larynx tumours denounce more significant problems between age groups) clearly influences Health Related Quality of Life perceptions. Conclusions: Geriatric oncology assessments signalize age-independent indicators that might guide oncologic geriatric care optimization. Decision-making in geriatric oncology must be based on tumour characteristics and chronological age but also on performance status evaluation, co-morbidity, and patient reported outcomes assessment.info:eu-repo/semantics/publishedVersio
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