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This chapter is organized to discuss the commonly used implantable antenna materials, in vitro, and in vivo testing. It discusses common conductors, their health effects, and alternate conductors in conjunction with biocompatibility and miniaturization techniques. Bench top testing discusses the mixture and measurement of in vitro gels, and common tests are performed on the bench top. The chapter provides an overview of in vivo testing, including different animal test models compared to a human test subject, dielectric mismatches between the dielectric properties of tissues seen in the literature and the tissues seen in the surgery room, and some practical testing considerations to perform antenna testing in a hospital or medical research facility. It concentrates on gelatin‐based semisolid tissue‐mimicking phantoms for the purpose of in vitro testing. The chapter also discusses the differences between human tissue and two common animal test models, porcine and rodent.

This article’s objective is to discuss the anatomical and technical challenges associated with designing subcutaneously implanted antennas for continuous wireless medical telemetry. One challenge in this design process is the connection between simulation setup and the anatomical layering of tissues in biological systems. This article presents an overview of the layers of tissues associated with subcutaneous implant (epidermis, dermis, and hypodermis) as well as the measured dielectric properties of these tissues. In addition, this study presents the design and measurement of an implantable dual-band antenna operating on the wireless medical telemetry service (WMTS) (1.395–1.432 GHz) and industrial, scientific, and medical (ISM) (2.4–2.5 GHz) communication bands. This antenna was validated ex vivo and in vivo using porcine animal models. The antenna has a simulated bandwidth of 2.3% for WMTS and 5.7% for ISM bands. In addition, the antenna saw a 300 MHz shift, ex vivo , to the right for WMTS while not having a shift for the ISM band. For in vivo validation, two antennas were made and tested in a porcine animal model and both show an adequate transmission range of 10 m.

This article discusses challenges in designing optically transparent antennas and filters for smart city applications. The smart city concept seeks to alleviate urban challenges that include infrastructure and network capacity. The proposed frequencies for the next generation of wireless networks (5G) would result in shorter broadcast distances and network dead zones. Additional access points and signal repeaters embedded into the existing infrastructure, by inserting transparent antennas into windows via either meshed conductors or transparent conductive oxides (TCOs), would help to mitigate these issues. Glass-embedded frequency-selective surfaces (FSSs) can be used anywhere that requires microwave filtering and optical transparency. The cyberphysical system security in this forthcoming network also poses challenges to entities that require strict network security. This article focuses mainly on TCOs, particularly doped zinc oxide (ZnO), as promising material for transparent antennas and filters. To demonstrate the potential of ZnOs as highly transparent conductive materials for antenna and filter applications, we designed, fabricated, and tested a gallium-doped ZnO- (GZO) based optically transparent 2.4-GHz Wi-Fi antenna and two FSSs (bandpass and bandstop filters) operating in the 23-29-GHz frequency range. These results confirm the potential for ZnO-based TCOs as suitable alternatives to indium tin oxide (ITO) for microwave applications.

This paper presents the design, fabrication, and test of antennas intended to be used for implantable biosensors. With the rising number of Americans managing chronic diseases, implantable biosensors offer better access to vital information for the management of these diseases. Diabetes, particularly, is managed by many through the means of a finger prick monitor, offering only a snap shot of blood glucose at a particular time without showing trends of a rise or fall in the glucose levels. Implantable sensors not only offer these trends via a continuous monitor, a fully implantable sensor offers these trends without the inconvenience of a monitoring system extending outside of the human body. Such appendages hinder the normal activity of patients monitoring their chronic diseases. Due to their full implantation, the sensor monitor needs to broadcast the analyte date from the human body outward to an external data collector. This broadcast requires an antenna made of a biocompatible antenna that operates on frequency bands allocated for medical telemetry as well as frequency bands allocated for unlicensed communication (e.g. WiFi and Bluetooth). This paper presents antennas designed using a biocompatible material Titanium Nitrite (TiN) for subcutaneous implant. The antennas presented operate on the Wireless Medical Telemetry System (WMTS) frequency band and the 2.4 GHz Industrial, Scientific, and Medical (ISM) frequency band.

This paper presents a biocompatible antenna for a subcutaneous implantable biosensor. With the large number of Americans who manage chronic diseases, biosensors offer the capability for better management of these diseases. For diabetes, particularly, the most common monitoring system used is a blood finger pricking system only offers snapshots of blood glucose levels and not trends of glucose changes. These limitations yield a demand for a monitoring system that can provide continuous data streams of glucose levels for better dietary and medicinal regimens. Fully implantable systems offer continuous monitoring while not sacrificing normal daily activities that implantable sensors with an external transmitter can pose. One bottleneck is the miniaturization of telecommunication system. Current implantable devices use the MedRadio band, which offer a challenge for antenna miniaturization for subcutaneous implantation. Additionally the use of copper as the radiator is a challenge due to biocompatibility. As a result there is a need for an implantable antenna that utilizes biocompatible materials, such as Titanium Nitrite (TiN). This paper presents the design and fabrication of a TiN antenna for subcutaneous implant operating in the 2.4 GHz ISM band. The simulation and in vivo test data are presented.

This contribution presents the design and simulation of finite size narrow band transmission filters for applications in realtime and remote short wave infrared (SWIR) spectroscopy and imaging. The results can ultimately be extended to hyperspectral imaging that has gained interest in many fields ranging from agriculture to surveillance. As chemical compounds possess unique set of sharp spectral signatures, they can be differentiated using wideband spectral scanning. However, such standard approaches require bulky instruments and long acquisition times together with post-processing of acquired data. These technological bottlenecks result in a diminished usefulness of such systems in scenarios demanding short response times, such as law enforcement, homeland security, and military applications. To overcome these limitations, narrow-band and pixel-size filters can be incorporated to focal plane arrays for real-time spectral imaging systems. In this study, we explored several designs of narrow-band, finite-sized (

Hedgehog and Wingless signaling in the Drosophila embryonic epidermis represents one paradigm for organizer function. In patterning this epidermis, Hedgehog and Wingless act asymmetrically, and consequently otherwise equivalent cells on either side of the organizer follow distinct developmental fates. To better understand the downstream mechanisms involved, we have investigated mutations that disrupt dorsal epidermal pattern. We have previously demonstrated that the gene lines contributes to this process. Here we show that the Lines protein interacts functionally with the zinc-finger proteins Drumstick (Drm) and Bowl. Competitive protein-protein interactions between Lines and Bowl and between Drm and Lines regulate the steady-state accumulation of Bowl, the downstream effector of this pathway. Lines binds directly to Bowl and decreases Bowl abundance. Conversely, Drm allows Bowl accumulation in drm-expressing cells by inhibiting Lines. This is accomplished both by outcompeting Bowl in binding to Lines and by redistributing Lines to the cytoplasm, thereby segregating Lines away from nuclearly localized Bowl. Hedgehog and Wingless affect these functional interactions by regulating drm expression. Hedgehog promotes Bowl protein accumulation by promoting drm expression, while Wingless inhibits Bowl accumulation by repressing drm expression anterior to the source of Hedgehog production. Thus, Drm, Lines, and Bowl are components of a molecular regulatory pathway that links antagonistic and asymmetric Hedgehog and Wingless signaling inputs to epidermal cell differentiation. Finally, we show that Drm and Lines also regulate Bowl accumulation and consequent patterning in the epithelia of the foregut, hindgut, and imaginal discs. Thus, in all these developmental contexts, including the embryonic epidermis, the novel molecular regulatory pathway defined here is deployed in order to elaborate pattern across a field of cells.

In this letter, we present a small implantable antenna for MedRadio (401-406 MHz) and ISM (433-434.8 MHz) bands. The antenna is designed to be implanted under the skin and therefore tested by using skin-mimicking gels. We found very good agreement between the simulated and measured return loss. The antenna provided reliable data telemetry up to 20 m when tested indoors.

Elongation of the Drosophila embryonic hindgut epithelium occurs by a process of oriented cell rearrangement requiring the genes drumstick (drm) and lines (lin). The elongating hindgut becomes subdivided into domains – small intestine, large intestine and rectum – each characterized by a specific pattern of gene expression dependent upon normal drm and lin function. We show that drm encodes an 81 amino acid (10 kDa) zinc finger protein that is a member of the Odd-skipped family. drm expression is localized to the developing midgut-hindgut junction and is required to establish the small intestine, while lin is broadly expressed throughout the gut primordium and represses small intestine fate. lin is epistatic to drm, suggesting a model in which localized expression of drm blocks lin activity, thereby allowing small intestine fate to be established. Further supporting this model, ectopic expression of Drm throughout the hindgut produces a lin phenotype. Biochemical and genetic data indicate that the first conserved zinc finger of Drm is essential for its function. We have thus defined a pathway in which a spatially localized zinc finger protein antagonizes a globally expressed protein, thereby leading to specification of a domain (the small intestine) necessary for oriented cell rearrangement.

Despite many advantages, there are major problems associated with the current microwave ablation systems. These problems are mainly due to the narrowband nature of the antennas used in these systems. Our data show that although at the start of the ablation procedure more than 90% of the power is transmitted into the tissue due to good antenna-to-tissue impedance matching, as the temperature increases in the tissue, power transmission efficiency drops down to as low as 20%. Such degradation in power delivery creates three major problems: (1) Most of the power is reflected back to the device causing extreme heating and creating unwanted ablation zones beyond the region of interest. Currently, this problem is addressed by cooling the antenna shaft which complicates the probe design and increases the cost. We discuss this issue in detail and provide references in the “background and significance” section. (2) More power from the generator is needed to create the desired ablation zone. Currently, the power levels are as high as 100Watts (W). Our preliminary data suggest that even 20W is enough to create the desired ablation zones with UMAT. (3) Unnecessary increase in ablation time. Total ablation time suffers because of the inefficient power delivery into the tissue.

Summary form only given. The conventional monitoring technologies at the bedside in the hospital consist of a body-worn device and central monitoring station with wired connections. At the hospital settings, the patients' vital parameters such as blood pressure, ECG, temperature, oxygen saturation can easily be monitored through a nurse stationed at the central monitoring station. Although this technology offers unique features and timely patient monitoring and treatment for patients in the clinic, there is no technology to continually monitor the health conditions of the patients after they are released from the hospital. Development of wireless telehealth technologies is critical in providing a solution to this clinical need. Such devices that can provide the wireless telemetry consist of three parts; the sensor, associated electronics and the telemetry unit. In this study, we develop an alternate communication approach using wireless communication and new display technologies to assist healthcare providers in monitoring patients outside the clinic. Our main concentration will be the telemetry link and associated electronics therefore we chose a temperature sensor to show the validity and functionality of the device. More specifically, we investigate the efficiency and practicability for a wireless network in a two channel temperature monitoring system. Two wireless protocols were investigated: a Bluetooth (IEEE 802.15.1) ad-hoc network and a Wi-Fi (IEEE 802.11) ad-hoc network. To do so, two subsystems were designed: a sensor system and a display system. The sensor system consists of two thermometers and a wireless transmitter/receiver. The data will be communicated to the display system wirelessly. The display consists of a wireless transmitter/receiver and a iOS mobile device. The results concerning the efficacy and practicability of the designed system and the integration with a radiometer will be presented.

Recently, Microwave (MW) ablation emerged as a new technology with potential to eliminate the problems associated with RF ablation. In contrast to RF ablation, MW ablation uses higher frequencies (915 MHz and 2.4 GHz) and work on an electromagnetic energy propagation principle. When the microwave power is turned on, an antenna on the MW probe radiates electromagnetic energy into the tissue creating the ablation zone. As a result, MW ablation can be used for many organs such as lung and bones with higher impedance values where RF ablation would fail. Although microwave ablation therapy offers unique advantages over conventional radio frequency ablation therapy such as reduced ablation time, larger ablation zones, elimination of ground pads etc., there are still major problems associated with the existing microwave ablation devices on the market. Current devices use either dipole or slot antennas to deposit electromagnetic energy into the tissue. Such antennas are known to be very narrow band. During the design process, these antennas are matched to the tissue impedance at the frequency of operation (existing devices work at 915 MHz or 2.4 GHz). However, as soon as the microwave power is turned on, the electrical properties of the tissue (dielectric constant - er and conductivity - σ) change due to increased temperature in the tissue. As a result, the power transmission characteristics of the entire system deteriorate. In order to better understand the power transmission characteristics of ablation antennas, we studied the microwave electrical properties of porcine liver, lung, and heart using the Agilent 805070 E slim form probe, a fiber optic temperature probe, and a smooth surface heat source. We manipulated the temperature from 25 °C to 80 °C and measured the dielectric properties between 500 MHz and 20 GHz.

Although microwave ablation offers unique advantages over RF ablation, there are still issues with current microwave ablation devices. This is because the current microwave ablation devices use either dipole or slot antennas to deposit electromagnetic energy into the tissue. Such antennas are known to be very narrow band. During the design process, these antennas are matched to the tissue impedance at the frequency of operation (existing devices work at 915 MHz or 2.4 GHz). However, as soon as the microwave power is turned on, the electrical properties of the tissue (dielectric constant - er and conductivity - σ) change due to increased temperature in the tissue. As a result, the power transmission characteristics of the entire system deteriorate. This temperature increase can be as high as 60 °C raising the local tissue temperature up to ~100 °C. In order to understand the overall ablation device treatment efficiency, there is a need to explore the effect of the temperature on power delivery into the tissue. Therefore, in this study, we investigate the power transmission characteristics of a printed dipole antenna within liver, lung and heart tissues. Two microstrip dipole antennas designed for both 915 MHz and 2.4 GHz. The liver, lung and heart tissues along with antennas and temperature probe, is placed on a heating element to increase the temperature of the tissue. The return loss was measured at 5 °C (indicated by the temperature probe) intervals from 25 °C to 80 °C. We will present results regarding the effect of temperature on power transmission efficiency.

The elucidation of pathways linking patterning to morphogenesis is a problem of great interest. We show here that, in addition to their roles in patterning and morphogenesis of the hindgut, the Drosophila genes drumstick ( drm ) and bowl are required in the foregut for spatially localized gene expression and the morphogenetic processes that form the proventriculus. drm and bowl belong to a family of genes encoding C 2 H 2 zinc finger proteins; the other two members of this family are odd-skipped ( odd ) and sob . In both the fore- and hindgut, drm acts upstream of lines ( lin ), which encodes a putative transcriptional regulator, and relieves its repressive function. In spite of its phenotypic similarities with drm , bowl was found in both foregut and hindgut to act downstream, rather than upstream, of lin . These results support a hierarchy in which Drm relieves the repressive effect of Lin on Bowl, and Bowl then acts to promote spatially localized expression of genes (particularly the JAK/STAT pathway ligand encoded by upd ) that control fore- and hindgut morphogenesis. Since the odd -family and lin are conserved in mosquito, mouse, and humans, we propose that the odd -family genes and lin may also interact to control patterning and morphogenesis in other insects and in vertebrates.

Previously we demonstrated that a cell line derived from mouse inner medullary collecting duct (mIMCD-K2) absorbs Na+ and secretes Cl- by electrogenic mechanisms and that arginine vasopressin (AVP) stimulates Cl- secretion. The objective of the present study was to determine whether hyperosmolality, both acute (minutes) and chronic (weeks), affects electrogenic Na+ absorption IscNa and electrogenic Cl- secretion IscCl across the IMCD. To this end, we measured IscNa and IscCl across monolayers of mIMCD-K2 cells mounted in Ussing-type chambers. Osmolality was increased from 290 to 590 mosmol/kgH2O by adding 200 mosmol/kgH2O of NaCl and 100 mosmol/kgH2O of urea or 300 mosmol/kgH2O of sucrose to the bathing solutions. Acute and chronic hyperosmolality reduced basal IscNa and IscCl and the AVP-stimulated rise in IscCl. These findings indicate that osmolality is an important determinant of IscNa and IscCl across IMCD cells and that the osmolality of the interstitial fluid should be considered when evaluating the effects of hormones and other factors on Na+ and Cl- transport by the IMCD.

Notch signaling controls formation of joints at leg segment borders and growth of the developing Drosophila leg. Here, we identify the odd-skipped gene family as a key group of genes that function downstream of the Notch receptor to promote morphological changes associated with joint formation during leg development. odd, sob, drm, and bowl are expressed in a segmental pattern in the developing leg, and their expression is regulated by Notch signaling. Ectopic expression of odd, sob, or drm can induce invaginations in the leg disc epithelium and morphological changes in the adult leg that are characteristic of endogenous invaginating joint cells. These effects are not due to an alteration in the expression of other genes of the developing joint. While odd or drm mutant clones do not affect leg segmentation, and thus appear to act redundantly, bowl mutant clones do perturb leg development. Specifically, bowl mutant clones result in a failure of joint formation from the distal tibia to tarsal segment 5, while more proximal clones cause melanotic protrusions from the leg cuticle. Together, these results indicate that the odd-skipped family of genes mediates Notch function during leg development by promoting a specific aspect of joint formation, an epithelial invagination. As the odd-skipped family genes are involved in regulating cellular morphogenesis during both embryonic segmentation and hindgut development, we suggest that they may be required in multiple developmental contexts to induce epithelial cellular changes.