Hepatic malignancies have historically been treated with surgical resection. Due to the shortcomings of this technique, there is interest in other, less invasive, treatment modalities, such as microwave hepatic ablation. Crucial to the development of this technique is the accurate knowledge of the dielectric properties of human liver tissue at microwave frequencies. To this end, we characterized the dielectric properties of in vivo and ex vivo normal, malignant and cirrhotic human liver tissues from 0.5 to 20 GHz. Analysis of our data at 915 MHz and 2.45 GHz indicates that the dielectric properties of ex vivo malignant liver tissue are 19 to 30% higher than normal tissue. The differences in the dielectric properties of in vivo malignant and normal liver tissue are not statistically significant (with the exception of effective conductivity at 915 MHz, where malignant tissue properties are 16% higher than normal). Also, the dielectric properties of in vivo normal liver tissue at 915 MHz and 2.45 GHz are 16 to 43% higher than ex vivo. No statistically significant differences were found between the dielectric properties of in vivo and ex vivo malignant tissue (with the exception of effective conductivity at 915 MHz, where malignant tissue properties are 28% higher than normal). We report the one-pole Cole-Cole parameters for ex vivo normal, malignant and cirrhotic liver tissue in this frequency range. We observe that wideband dielectric properties of in vivo liver tissue are different from the wideband dielectric properties of ex vivo liver tissue, and that the in vivo data cannot be represented in terms of a Cole-Cole model. Further work is needed to uncover the mechanisms responsible for the observed wideband trends in the in vivo liver data.

Abstract-We report a novel coaxial antenna for hepatic microwave ablation. This device uses a floating sleeve, that is, a metal conductor electrically isolated from the outer connector of the antenna coaxial body, to achieve a highly localized specific absorption rate pattern that is independent of insertion depth. This floating sleeve coaxial dipole antenna has low power reflection in the 2.4-GHz IMS band. Ex vivo experiments confirm our numerical simulation results.

Disaster-related interventions are actions or responses undertaken during any phase of a disaster to change the current status of an affected community or a Societal System. Interventional disaster research aims to evaluate the results of such interventions in order to develop standards and best practices in Disaster Health that can be applied to disaster risk reduction. Considering interventions as production functions (transformation processes) structures the analyses and cataloguing of interventions/responses that are implemented prior to, during, or following a disaster or other emergency. Since currently it is not possible to do randomized, controlled studies of disasters, in order to validate the derived standards and best practices, the results of the studies must be compared and synthesized with results from other studies (ie, systematic reviews). Such reviews will be facilitated by the selected studies being structured using accepted frameworks. A logic model is a graphic representation of the transformation processes of a program [project] that shows the intended relationships between investments and results. Logic models are used to describe a program and its theory of change, and they provide a method for the analyzing and evaluating interventions. The Disaster Logic Model (DLM) is an adaptation of a logic model used for the evaluation of educational programs and provides the structure required for the analysis of disaster-related interventions. It incorporates a(n): definition of the current functional status of a community or Societal System, identification of needs, definition of goals, selection of objectives, implementation of the intervention(s), and evaluation of the effects, outcomes, costs, and impacts of the interventions. It is useful for determining the value of an intervention and it also provides the structure for analyzing the processes used in providing the intervention according to the Relief/Recovery and Risk-Reduction Frameworks.

A Conceptual Framework upon which the study of disasters can be organized is essential for understanding the epidemiology of disasters, as well as the interventions/responses undertaken. Application of the structure provided by the Conceptual Framework should facilitate the development of the science of Disaster Health. This Framework is based on deconstructions of the commonly used Disaster Management Cycle. The Conceptual Framework incorporates the steps that occur as a hazard progresses to a disaster. It describes an event that results from the changes in the release of energy from a hazard that may cause Structural Damages that in turn, may result in Functional Damages (decreases in levels of function) that produce needs (goods and services required). These needs can be met by the goods and services that are available during normal, day-to-day operations of the community, or the resources that are contained within the community's Response Capacity (ie, an Emergency), or by goods and services provided from outside of the affected area (outside response capacities). Whenever the Local Response Capacity is unable to meet the needs, and the Response Capacities from areas outside of the affected community are required, a disaster occurs. All responses, whether in the Relief or Recovery phases of a disaster, are interventions that use the goods, services, and resources contained in the Response Capacity (local or outside). Responses may be directed at preventing/mitigating further deterioration in levels of functions (damage control, deaths, injuries, diseases, morbidity, and secondary events) in the affected population and filling the gaps in available services created by Structural Damages (compromise in available goods, services, and/or resources; ie, Relief Responses), or may be directed toward returning the affected community and its components to the pre-event functional state (ie, Recovery Responses). Hazard Mitigation includes interventions designed to decrease the likelihood that a hazard will cause an event, and should an event occur, that the amount of energy released will be reduced. Capacity Building consists of all interventions undertaken before an event occurs in order to increase the resilience of the community to an event related to a hazard that exists in an area-at-risk. Resilience is the combination of the Absorbing, Buffering, and Response Capacities of a community-at-risk, and is enhanced through Capacity-Building efforts. A disaster constitutes a failure of resilience.

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The principal goal of research relative to disasters is to decrease the risk that a hazard will result in a disaster. Disaster studies pursue two distinct directions: (1) epidemiological (non-interventional); and (2) interventional. Both interventional and non-interventional studies require data/information obtained from assessments of function. Non-interventional studies examine the epidemiology of disasters. Interventional studies evaluate specific interventions/responses in terms of their effectiveness in meeting their respective objectives, their contribution to the overarching goal, other effects created, their respective costs, and the efficiency with which they achieved their objectives. The results of interventional studies should contribute to evidence that will be used to inform the decisions used to define standards of care and best practices for a given setting based on these standards. Interventional studies are based on the Disaster Logic Model (DLM) and are used to change or maintain levels of function (LOFs). Relief and Recovery interventional studies seek to determine the effects, outcomes, impacts, costs, and value of the intervention provided after the onset of a damaging event. The Relief/Recovery Framework provides the structure needed to systematically study the processes involved in providing relief or recovery interventions that result in a new LOF for a given Societal System and/or its component functions. It consists of the following transformational processes (steps): (1) identification of the functional state prior to the onset of the event (pre-event); (2) assessments of the current functional state; (3) comparison of the current functional state with the pre-event state and with the results of the last assessment; (4) needs identification; (5) strategic planning, including establishing the overall strategic goal(s), objectives, and priorities for interventions; (6) identification of options for interventions; (7) selection of the most appropriate intervention(s); (8) operational planning; (9) implementation of the intervention(s); (10) assessments of the effects and changes in LOFs resulting from the intervention(s); (11) determination of the costs of providing the intervention; (12) determination of the current functional status; (13) synthesis of the findings with current evidence to define the benefits and value of the intervention to the affected population; and (14) codification of the findings into new evidence. Each of these steps in the Framework is a production function that facilitates evaluation, and the outputs of the transformation process establish the current state for the next step in the process. The evidence obtained is integrated into augmenting the respective Response Capacities of a community-at-risk. The ultimate impact of enhanced Response Capacity is determined by studying the epidemiology of the next event.

Electromuscular incapacitating devices (EMDs), such as Tasers, deliver high current, short duration pulses that cause muscular contractions and temporarily incapacitate the human subject. Some reports suggest that EMDs can kill. To help answer the question, "Can the EMD directly cause ventricular fibrillation (VF)?", ten tests were conducted to measure the dart-to-heart distance that causes VF in anesthetized pigs [mass = 64 kg +/- 6.67 standard deviation (SD)] for the most common X26 Taser. The dart-to-heart distance that caused VF was 17 mm +/- 6.48 (SD) for the first VF event and 13.7 mm +/- 6.79 (SD) for the average of the successive VF events. The result shows that when the stimulation dart is close enough to the heart, X26 Taser current will directly trigger VF in pigs. Echocardiography of erect humans shows skin-to-heart distances from 10 to 57 mm (dart-to-heart distances of 1-48 mm). These results suggest that the probability of a dart on the body landing in 1 cm2 over the ventricle and causing VF is 0.000172.