Goran Stojanovic

Monitoring of Water Content in Building Materials Using a Wireless Passive Sensor

This paper describes an innovative design of a wireless, passive LC sensor and its application for monitoring of water content in building materials. The sensor was embedded in test material samples so that the internal water content of the samples could be measured with an antenna by tracking the changes in the sensor’s resonant frequency. Since the dielectric constant of water was much higher compared with that of the test samples, the presence of water in the samples increased the capacitance of the LC circuit, thus decreasing the sensor’s resonant frequency. The sensor is made up of a printed circuit board in one metal layer and water content has been determined for clay brick and autoclaved aerated concrete block, both widely used construction materials. Measurements were conducted at room temperature using a HP-4194A Impedance/Gain-Phase Analyzer instrument.

Analysis, design, and characterization of ferrite EMI suppressors

In this paper design, modeling and characterization of single and double coils, which consist of conductive layer embedded in the soft ferrite material, are described. These surface-mount components, comprising of a cofired multilayered ferrite and coil, have been developed in the ceramic coprocessing technology. A simple analytical model of proposed structures is presented. This model is very suitable for circuit simulations and for prediction of frequency characteristics of considered inductors. The inductance and impedance of coils embedded in low permeability or high permeability ferrite material are calculated and compared. Also, these suppressors were experimentally tested in the frequency range 1 MHz-3 GHz using an Agilent 4287 A RF LCR meter. The calculated results were in good agreement with the measured ones.

Advanced bronchoscopic techniques in diagnosis and staging of lung cancer

The role of advanced brochoscopic diagnostic techniques in detection and staging of lung cancer has steeply increased in recent years. Bronchoscopic imaging techniques became widely available and easy to use. Technical improvement led to merging in technologies making autofluorescence or narrow band imaging incorporated into one bronchoscope. New tools, such as autofluorescence imagining (AFI), narrow band imaging (NBI) or fuji intelligent chromo endoscopy (FICE), found their place in respiratory endoscopy suites. Development of endobronchial ultrasound (EBUS) improved minimally invasive mediastinal staging and diagnosis of peripheral lung lesions. Linear EBUS proven to be complementary to mediastinoscopy. This technique is now available in almost all high volume centers performing bronchoscopy. Radial EBUS with mini-probes and guiding sheaths provides accurate diagnosis of peripheral pulmonary lesions. Combining EBUS guided procedures with rapid on site cytology (ROSE) increases diagnostic yield even more. Electromagnetic navigation technology (EMN) is also widely used for diagnosis of peripheral lesions. Future development will certainly lead to new improvements in technology and creation of new sophisticated tools for research in respiratory endoscopy. Broncho-microscopy, alveoloscopy, optical coherence tomography are some of the new research techniques emerging for rapid technological development.

Narrow Band Imaging Videobronchoscopy Improves Assessment of Lung Cancer Extension and Influences Therapeutic Strategy

OBJECTIVE Narrow band imaging (NBI) videobronchoscopy is a new technique aimed at lung cancer detection. This study investigated its sensitivity and specificity for evaluation of lung cancer extension and its possible influence on therapeutic decision, compared with white light videobronchoscopy. METHODS In this prospective study, we evaluated 106 patients with suspected lung cancer. All patients were examined using EVIS LUCERA videoendoscopy system. In every patient, at least three biopsies were taken from places visualized as pathologic, surrounding primary tumor, and three biopsies from places that appeared normal. The overall number of biopsies performed in 106 patients was 636. RESULTS The specificity and sensitivity of NBI in revealing greater lung cancer extension were 85.6% and 95%, respectively; positive and negative predictive values were 84% and 95.6%, respectively. Specificity and sensitivity were significantly better when compared with white light bronchoscopy alone (P < 0.01). NBI led to the change in therapeutic decision in 14 patients. There was statistically significant correlation between NBI assessment of tumor extension and change in therapeutic decision (P < 0.000). CONCLUSIONS NBI showed significantly better specificity and sensitivity in the assessment of lung cancer extension. NBI proved that it might have potential influence on therapeutic decision, making it more accurate. The procedure is safe and easily deployed in everyday practice.

A Compact Inductive Position Sensor Made by Inkjet Printing Technology on a Flexible Substrate

This paper describes the design, simulation and fabrication of an inductive angular position sensor on a flexible substrate. The sensor is composed of meandering silver coils printed on a flexible substrate (Kapton film) using inkjet technology. The flexibility enables that after printing in the plane, the coils could be rolled and put inside each other. By changing the angular position of the internal coil (rotor) related to the external one (stator), the mutual inductance is changed and consequently the impedance. It is possible to determine the angular position from the measured real and imaginary part of the impedance, in our case in the frequency range from 1 MHz to 10 MHz. Experimental results were compared with simulation results obtained by in-house developed software tool, and very good agreement has been achieved. Thanks to the simple design and fabrication, smaller package space requirements and weight, the presented sensor represents a cost-effective alternative to the other sensors currently used in series production applications.

Autofluorescence Imaging Videobronchoscopy Improves Assessment of Tumor Margins and Affects Therapeutic Strategy in Central Lung Cancer

OBJECTIVE Autofluorescence imaging (AFI) videobronchoscopy is a new endoscopic tool that improves visualization of neoplastic changes in the bronchial mucosa. The major aim of our study was to determine sensitivity and specificity of the technique in the assessment of tumor extent (margins). The secondary objective was to evaluate the possible effect of AFI on the change in therapeutic decisions of lung cancer treatment. METHODS In this prospective trial, we enrolled 104 patients in whom we performed 624 targeted biopsies, 3 from the pathologically altered mucosa (red-brownish or magenta colored) and 3 from randomly picked normal areas. We were using the Olympus BF-F260 videobronchoscope and EVIS LUCERA system. White light videobronchoscopy (WLB) preceded AFI examination and biopsy collection. All biopsy specimens were examined by a pathologist blinded to bronchoscopy findings, and where applicable surgically resected specimens were examined. RESULTS In 14.4% of the patients, AFI revealed a greater extent of the tumor than WLB, and in 11.5% that finding led to change in therapeutic decision (lesser or greater resection or avoidance of surgery). We found a significant correlation between tumor extent determined by AFI and changes in therapeutic decisions (P < 0.01). Sensitivity, specificity, positive predictive value and negative predictive value for AFI in the assessment of tumor extension were 93%, 92%, 92% and 93%, respectively. Corresponding results for WLB were 84%, 79%, 77% and 85%, respectively. Relative sensitivity of AFI is 1.11. CONCLUSIONS Our results confirm that AFI videobronchoscopy significantly improves the assessment of central lung cancer extension and influences the therapeutic strategy. This technique has greater sensitivity and specificity, in assessment of tumor margins, than WLB alone.

Design, Modeling, and Analysis of a Compact Planar Transformer

This paper presents a new design of a planar transformer. Over the surface of a flat core, meander-type design was engraved, so that symmetrically adjusted primary and secondary coils, of the same meander-type, can fit into the engraved design. Primary and secondary coils were covered with another flat core consequently forming a compact planar transformer. Windings of primary and secondary coils are printed on both sides of PCB. Conductive stripes of a winding from upper and bottom layer are connected by vias. The transformer was analyzed when the primary and secondary coils were without a core and with a core. High frequency parameters of the transformer were obtained by finite element modeling software and Impedance Analyzer HP4194A in the frequency range from 50 kHz to 1 MHz. The transformer is intended to be used in DC-DC converters (for switching frequency up to several hundred kHz).

Micro force sensor fabricated in the LTCC technology

This paper presents resonant force sensor designed for the operation in the MHz range and for 0 to 6 N load. The LTCC technology is implemented for the sensor fabrication and a wireless readout of the measured data is provided. Used LTCC tape is characterised in order to demonstrate its mechanical and electrical properties at room temperature. Also, theoretical model of the sensor is developed to predict its behaviour. Fabricated sensor performance is experimentally characterised and obtained results are in good agreement with the ones derived from the presented theoretical model.

Autofluorescence videobronchoscopy (AFI) for the assessment of tumor extension in lung cancer.

The major objective of our study was to determine the specificity and sensitivity of AFI videobronchoscopy vs. white light videobronchoscopy, in the assessment of lung cancer extent. Secondary objective was to investigate whether or not AFI can reveal greater extension of the tumor, and can it influence therapy making decision. Autofluorescence videobronchoscopy systems are new technology for visualization of bronchial mucosa, and the proper indications for such systems will be determined in the near future. In this prospective trial we have enrolled 27 patients with suspected lung cancer in whom we performed 108 diagnostic biopsies and 54 control biopsies. All patients underwent WL videobronchoscopy followed by Auto Fluorescence Imaging (AFI) examination of tracheobronchial tree. We were using videobronchoscope BF-F260 and EVIS LUCERA SPECTRUM processor unit. Overall specificity for AFI in the diagnostics of lung cancer was found to be 85%, sensitivity was 90%, positive predictive value (PPV) 78%, and negative predictive value (NPV) 94%. Specificity, sensitivity, PPV, and NPV for WL videobronchoscopy in lung cancer diagnostics were 54%, 64%, 51%, and 69%, respectively. Relative sensitivity ratio of AFI over WL videobronchoscopy, which is calculated to be 1.41, confirmed superiority of AFI in lung cancer diagnostics. We confirmed significant correlation between the greater extension of the tumor (assessed with AFI) and the therapeutical decision in lung cancer treatment (p = 0.01). Influence of AFI on therapeutical decision was significant (p = 0.034). AFI videobronchoscopy system yields significantly higher sensitivity and specificity for the assessment of lung cancer extent than WLB videobronchoscopy alone. It had shown to be able to influence therapeutic option for lung cancer treatment. Further studies are needed to evaluate and validate these results.

Novel efficient methods for inductance calculation of meander inductor

Purpose – Present 3D electromagnetic simulators have high accuracy but they are time and memory expensive. Owing to a fast and simple expression for inductance is also necessary for initial inductor design. In this paper, new efficient methods for total inductance calculation of meander inductor, are given. By using an algorithm, it is possible to predict correctly all inductance variations introduced by varying geometry parameters such as number of turns, width of conductor or spacing between conductors.Design/methodology/approach – The starting point for the derivation of the recurrent formula is Greenhouse theory. Greenhouse decomposed inductor into its constituent segments. Meander inductor is divided into straight conductive segments. Then the total inductance of the meander inductor is a sum of self‐inductances of all segments and the negative and positive mutual inductances between all combinations of straight segments. The monomial equation for the total inductance of meander inductor has been obt...