Small Epidermal Antennas

Small magnetic loop antennas are proposed as skin transfer tattoos to overcome the efficiency limitations of human tissue and variability of detuning

Chitinase and Fizz family members are a generalized feature of nematode infection with selective Upregulation of Ym1 and F10.1 by antigen-presenting cells

Ym1 and Fizz1 are secreted proteins that have been identified in a variety of Th2-mediated inflammatory settings. We originally found Ym1 and Fizz1 as highly expressed macrophage genes in a Brugia malayi infection model. Here, we show that their expression is a generalized feature of nematode infection and that they are induced at the site of infection with both the tissue nematode Litomosoides sigmodontis and the gastrointestinal nematode Nippostrongylus brasiliensis. At the sites of infection with N. brasiliensis, we also observed induction of other chitinase and Fizz family members (ChaFFs): acidic mammalian chitinase (AMCase) and Fizz2. The high expression of both Ym1 and AMCase in the lungs of infected mice suggests that abundant chitinase production is an important feature of Th2 immune responses in the lung. In addition to expression of ChaFFs in the tissues, Ym1 and Fizz1 expression was observed in the lymph nodes. Expression both in vitro and in vivo was restricted to antigen-presenting cells, with the highest expression in B cells and macrophages. ChaFFs may therefore be important effector or wound-repair molecules at the site of nematode infection, with potential regulatory roles for Ym1 and Fizz1 in the draining lymph nodes

Popup Tunable Frequency Selective Surfaces for Strain Sensing

A 3D popup frequency selective surface (FSS) is presented that can be tuned by the amount of strain due to mechanical loading in its elastomeric substrate. The proposed FSS structure comprises periodic two-dimensional (2D) crossed dipoles attached to the substrate at selective bonding sites. Strain release in the substrate induces compressive stress in the attached FSS, converting it to a 3D periodic pattern. With the out of plane displacement, the interaction with the incident field and mutual interactions between the elements are altered, resulting in a resonant frequency shift and a more stable response regarding the incident angles from 0o to 45o. A design of popup FSS structure is introduced for strain sensing applications. The potential sensor can measure up to 50% strain in the substrate by frequency down-shift from 3.1 GHz to 2.4 GHz. Multiphysics Finite Element Method (FEM) modeling of the mechanical and RF simulation was in good correlation with the experimental data and demonstrates the potential of these structures as sensors

An On Body Accelerometer System for streaming therapy data using COTS UHF RFID

This paper details the use of an on body Accelerometer COTS RFID system for use in determining specific therapeutic movements, and the performance of said movements. Conventional methodologies rely on power intensive Bluetooth or Wi-Fi technologies for live communications, but this paper outlines the use of ultra-low power battery assistive passive modes on UHF RFID chips to harness sub-2mW continuous streaming of Accelerometer data

Minimally invasive battery-less microcontroller enabled implantable NFC tag for healthcare sensing applications

This paper presents a minimally invasive battery-less microcontroller enabled implant that utilizes near-field communication technology to both power and transfer data to and from the implanted device. The implant has been designed around a cylindrical glass vial for its housing, of the type found in pet and livestock identification. Requiring just an injector assembly for implantation it can be deemed as minimally invasive. The prototype tag incorporates a near-field communication front end, providing data transfer and power to a microcontroller and a light emitting diode array, with a maximum measured read range of ~ 5 mm off the skin surface. Although light technology can be used for neural stimulation here it is used as a proof of concept before enabling further sensing modalities. The tag is proposed for use as a wireless platform for patient health monitoring in both clinical and home environments using a smartphone as the reader. It could also have applications in general wellbeing monitoring or sports

Utilizing Everyday Metallic Structures as UHF RFID Antennas

This paper introduces a technique where everyday metallic objects can be made resonant at a frequency of interest and to function as an antenna. This is achieved by the coupling of parallel resonant devices referred to as “Linear Resonators” to a metallic structure, where the Linear Resonator fundamentally operates as a passive frequency selective switch. Presented here is an initial proof of concept design targeted at the European RFID band. The design performance is evaluated both by simulation and practical measurements on various tubular structures

Effect of symmetry reduction on the spin dynamics of (001)-oriented GaAs quantum wells

Spin quantum beat spectroscopy is employed to investigate the in-plane anisotropy of the spin dynamics in (001) GaAs/AlGaAs quantum wells induced by an external electric field. This technique allows the anisotropy of the spin relaxation rate Γs and the electron Landé g factor g* to be measured simultaneously. The measurements are compared to similar data from (001) GaAs/AlGaAs quantum wells with applied shear strain and asymmetric barrier growth. All of these operations act to reduce the symmetry compared to that of a symmetric (001) quantum well in an identical manner (D2d → C2v). However, by looking at the anisotropy of both Γs and g* simultaneously we show that the microscopic actions of these symmetry breaking operations are very different. The experiments attest that although symmetry arguments are a very useful tool to identify the allowed spin dependent properties of a material system, only a microscopic approach reveals if allowed anisotropies will manifest. © 2013 American Physical Society

11D supergravity at O(l3){\cal O}(l^3)

We compute certain spinorial cohomology groups controlling possible supersymmetric deformations of eleven-dimensional supergravity up to order $l^3$ in the Planck length. At ${\cal O}(l)$ and ${\cal O}(l^2)$ the spinorial cohomology groups are trivial and therefore the theory cannot be deformed supersymmetrically. At ${\cal O}(l^3)$ the corresponding spinorial cohomology group is generated by a nontrivial element. On an eleven-dimensional manifold $M$ such that $p_1(M)\neq 0$, this element corresponds to a supersymmetric deformation of the theory, which can only be redefined away at the cost of shifting the quantization condition of the four-form field strength.Comment: 10 pages, 1 figure. v2: references adde

An 8-bit UHF RFID tag for passive sensing applications

This paper presents a passive UHF RFID tag consisting of a single dipole antenna matched to multiple RFID devices, where each is programmed with a unique binary weighting in its EPC register. With each device having its own digital input this results in a single tag capable of binary counting or a tag with multiple inputs. Measurement results and associated reader software demonstrate a proof of concept for an 8-bit version of the tag