Current source enhancements in Electrical Impedance Spectroscopy (EIS) to cancel unwanted capacitive effects

Electrical Impedance Spectroscopy (EIS) has emerged as a non-invasive imaging modality to detect and quantify functional or electrical properties related to the suspicious tumors in cancer screening, diagnosis and prognosis assessment. A constraint on EIS systems is that the current excitation system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIS is an ill-posed inverse problem which depends on the noise level in EIS measured data and regularization parameter in the reconstruction algorithm. There is high complexity in the design of stable current sources, with stray capacitance reducing the output impedance and bandwidth of the system. To confront this, we have designed an EIS current source which eliminates the effect of stray capacitance and other impacts of the capacitance via a variable inductance. In this paper, we present a combination of operational CCII based on a generalized impedance converter (OCCII-GIC) with a current source. The aim of this study is to use the EIS system as a biomedical imaging technique, which is effective in the early detection of breast cancer. This article begins with the theoretical description of the EIS structure, current source topologies and proposes a current conveyor in application of a Gyrator to eliminate the current source limitations and its development followed by simulation and experimental results. We demonstrated that the new design could achieve a high output impedance over a 3MHz frequency bandwidth when compared to other types of GIC circuits combined with an improved Howland topology

Sustainable forest management in Iran: a factor analysis

Since 1996, several Forest Resources Management Plans (FRMPs) have been launched by the Iranian government in order to approach sustainable forest management in the Zagros area in west and south-west Iran. This survey study aimed to provide some policy recommendations in order to launch more successful FRMPs. Using a proportional cluster random sampling method, data were collected from 208 forest-dwellers (beneficiaries) and 90 practitioners. The results showed that the FRMPs are far from satisfactory. There are several reasons for this failure. First, the financial resources allocated to these plans are being used for other purposes. Second, the inputs and supplies needed for effective forest management interventions were not in place in a timely manner. Third, the forest management in the area is far from being decentralized. Both the beneficiaries and practitioners believe that forest-dwellers play a weak role in forest management interventions. Factor analysis revealed that three main factors influencing the Zagros management effectiveness are "the management capabilities of forest-dwellers", "the professional capabilities of practitioners in forest management", and "public support for forest-dwellers". The correlation analysis revealed that all the three factors are also positively and significantly associated with the success of the government's forestry programs. Accordingly, the main recommendation of this study was to reformulate forest management policies in the Zagros area by highlighting participatory approaches, not only as a tool, but also as a goal of FRMPs

Multi-stakeholder involvement and urban green space performance

This study aimed to identify the main factors influencing urban green space performance. Therefore, a conceptual framework on the relations of multi-stakeholder involvement (MSI) and the performance was conducted by a mixed-method approach. The study covered all urban green space projects (UGSPs) published in international journals as its population which were obtained from three main databases: ISI Web of Knowledge, Scopus and Picarta. Using a few combinations of keywords, 29 relevant journals were identified, which included 42 UGSPs as the main units of analysis in this study. A content analysis was used to determine the contribution of MSI to the performance of urban green space. The main internal (state, private, society, planning/design, implementation, maintenance, input for management, and financial support) and external (regulation, good leadership and financial support) MSI indicators were further identified. The findings showed that the main indicators that significantly influence urban green space performance are 'state, society, implementation and regulation'. The study concluded that the state plays a critical role in the UGSPs' performance although it is not the only actor. The influential role of the state and society should also be considered since most of green space projects are non-profit oriented. 'Society' involvement also contributes to the performance and 'regulation' is also needed as a legal basis for green space development and management. To validate the conceptual framework and mixed-method approach developed here, it is recommended that more studies should be conducted to compare the relationship of the MSI and the UGSPs' performance in different categories

A socio-psychological investigation into limitations and incentives concerning reporting a clinically suspect situation aimed at improving early detection of classical swine fever outbreaks

The aim of this study was to identify limitations and incentives in reporting clinically suspect situations, possibly caused by classical swine fever (CSF), to veterinary authorities with the ultimate aim to facilitate early detection of CSF outbreaks. Focus group sessions were held with policy makers from the veterinary authorities, and representatives of veterinary practitioners and pig farmer unions. Personal interviews with a small group of pig farmers and practitioners were held to check limitations raised and solutions proposed during the focus group sessions. An electronic questionnaire was mailed to pig farmers and practitioners to investigate perceptions and attitudes with respect to clinically suspect situations possibly caused by CSF. After triangulating the responses of veterinary authorities, veterinary practitioners and farmers, six themes emerged across all groups: (1) lack of knowledge on the early signs of CSF; (2) guilt, shame and prejudice; (3) negative opinion on control measures; (4) dissatisfaction with post-reporting procedures; (5) lack of trust in government bodies; (6) uncertainty and lack of transparency of reporting procedures. The following solutions to facilitate early detection of CSF were put forward: (a) development of a clinical decision-support system for vets and farmers, in order to get faster diagnosis and detection of CSF; (b) possibility to submit blood samples directly to the reference laboratory to exclude CSF in a clinical situation with non-specific clinical signs, without isolation of the farm and free of charge for the individual farmer; (c) decrease social and economic consequences of reporting CSF, for example by improving the public opinion on first reports; (d) better schooling of veterinary officers to deal with emotions and insecurity of farmers in the process after reporting; (e) better communication of rules and regulations, where to report, what will happen next; (f) up-to-date website with information and visual material of the clinical signs of CS

Using planar electrical impedance tomography as a structural health monitoring method to detect and evaluate the damage to CFRP composite

Electrical Impedance Tomography (EIT) is an emerging imaging modality that produces either a 2D or 3D impedance image (conductivity or impedivity) of the subject under test. In this study we tested and demonstrated a new application of applying an EIT system to detect delamination and evaluate the damage location, size, strain and severity for Structure Health Monitoring (SHM) of composites (i.e. Carbonfibre-reinforced polymer (CFRP) composites)

Comparing the indicators of general health among two groups of female Quran memorizers and non- memorizers in Kermanshah, Iran

For downloading the full-text of this article please click here.Background and Objective: General health has always been a critical issue in human’s life. Religion and religious education is influential in individuals’ general health. Thus, the purpose of this descriptive study was to determine the effect of Quran memorization on general health.Method: This study used a simple random sampling procedure to select 106 female Quran memorizers and 91 non-memorizers. With respect to the collected data, the demographic information, such as age, marital status, education, and occupation, was elicited; in addition, general health was measured using the General Health Questionnaire (GHQ-28). The data were analyzed through comparison of means to spot the group differences. In this study, all the ethical issues were considered; moreover, the authors declare no conflict of interest.Results: The results of the study revealed that Quran memorizers were in a better status in terms of general health when compared with the non-memorizers. Accordingly, there were significant differences between the two groups in terms of stress, sleep disorders, depression, and physical signs. Furthermore, a significant difference was detected in terms of social functioning.Conclusion: Since Quran memorizers enjoyed better general health, it could be concluded that extending Quran principles and realizing their effects on individuals’ general health could provide greater understanding of Quran and its potential for treating psychological disorders, hence promoting psychological and mental health.For downloading the full-text of this article please click here.

A high-performance, multi-frequency micro-controlled Electrical Impedance Mammography (EIM) excitation and phantom validation system

The research concentrates on the design, development and calibration of a high performance Electrical Impedance Mammography (EIM) system for early detection of breast cancer at the macro and micro scale (at an early stage applicable for different breast sizes and shapes). The enhancement of the Electrical Impedance Tomography (EIT) system focuses on developing electrical and electronic instrumentations and improving the current source topologies to make them operate at multiple frequencies for the purpose of measuring permittivity and conductivity of different breast tissues. The calibration, assessment systems have employed current calibration in the EIT to evaluate the impedance distribution. This facilitates the acquisition of accurate impedance images to enable images of the internal structure of the breast to be constructed. A constraint on EIT systems is that the current injection system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIT is an ill-posed inverse problem which depends on the noise level in EIT measured data and regularization parameter in the reconstruction algorithm. This research aims are to prevent this problem by using a capacitance cancellation method based on a General Impedance Converter (GIC) implemented by operation of a second generation of current conveyor called OCCII-GIC and calibration methods to facilitate operation in the high frequency range. An EIT system based on a planar 85-electrode channel and using a Microcontroller unit (MCU) for addressing control between 85 electrodes and implementing calibration methods has been constructed. In EIT systems, assessment, validation of the performance and calibration of systematic errors in the electrical field generated inside of the interrogated volume is important. Evaluation of the EIT system will be assessed using a realistic electronic phantom (E-phantom). This enables the evaluation of the different conductivity values of the tissue, which has been created and evaluated based on the RSC circuit model for the different electrical conductivities and electrical impedivities in breast tissue

The Accuracy of Emergency Physicians in Ultrasonographic Screening of Acute Appendicitis; a Cross Sectional Study

Introduction: Diagnostic values reported for ultrasonographic screening of acute appendicitis vary widely and are dependent on the operator’s skill, patient’s gender, weight, etc. The present study aimed to evaluate the effect of operator skill on the diagnostic accuracy of ultrasonography in detection of appendicitis by comparing the results of ultrasonography done by radiologists and emergency physicians.Methods: This prospective diagnostic accuracy was carried out on patients suspected to acute appendicitis presenting to EDs of 2 hospitals. After the initial clinical examinations, all the patients underwent ultrasonography for appendicitis by emergency physician and radiologist, respectively. The final diagnosis of appendicitis was based on either pathology report or 48-hour follow-up. Screening performance characteristics of appendix ultrasonography by emergency physician and radiologist were compared using STATA 11.0 software.Results: 108 patients with the mean age of 23.91 ± 7.46 years were studied (61.1% male). Appendicitis was confirmed for 37 (34.26%) cases. Cohen's kappa coefficient between ultrasonography by the radiologist and emergency physician in diagnosis of acute appendicitis was 0.51 (95% CI: 0.35 – 0.76). Area under the ROC curve of ultrasonography in appendicitis diagnosis was 0.78 (95% CI: 0.69 – 0.86) for emergency physician and 0.88 (95% CI: 0.81 – 0.94) for radiologist (p = 0.052). Sensitivity and specificity of ultrasonography by radiologist and emergency physician in appendicitis diagnosis were 83.87% (95% CI: 67.32 – 93.23), 91.5% (95% CI: 81.89 – 96.52), 72.97% (95% CI: 55.61 – 85.63), and 83.10% (95% CI: 71.94 – 90.59), respectively.Conclusion: Findings of the present study showed that the diagnostic accuracy of ultrasonography carried out by radiologist (89%) is a little better compared to that of emergency physician (80%) in diagnosis of appendicitis, but none are excellent.

An Electronic Mesh phantom for planar structure EIS systems

There are two phantom types to assess EIT or EIS systems: physical and electronic phantoms. The physical phantom that is used for EIT or EIS systems typically is composed of a conductive saline solution or gel medium with objects embedded in this medium. The medium and object have different impedances, which permit the system to detect changes of impedance and image them. Physical phantoms have common problems of: short life, inflexibility, instability and uncontrollable physical characteristics. The E-phantom is used to assess the system characteristics of the EIT or EIS systems such as: current or voltage delivered, internal stray impedance and the effects of the impedance of the medium on the measurements. These results can then be used to optimise the electronic circuitry and components relevant to the impedance measurements to improve the performance of the system. Thus, the advantages of an E-phantom compared with a physical phantom are: improved quality, reproducibility, predictability and stability of signals. The Sussex EIS system is based on a planar 85-electrodes structure located at the bottom of the tank. Figure 1 shows planar 85-electrodes and 2D and 3D meshes of the system