Elf: computer automation and error correction for a microwave network analyzer

A microwave measurement system has been developed that combines a personal computer (PC) and an conventional vector network analyzer to yield a full complex-error-corrected automatic network analyzer. The system consists of a Hewlett-Packard HP 8410C network analyzer, an HP 8350B sweep oscillator, and an IBM PC. A program called Elf runs on the PC, performing calibration and measurement algorithms and providing a flexible, menu-oriented user interface. The system, when calibrated, achieves a worst-case measurement error vector of magnitude ≤ 0.02 for transmission and reflection coefficient measurements over the 2-12.4-GHz frequency range and has a measurement speed of three frequency points/s. Elf provides an inexpensive method for upgrading the HP 8410 to achieve the high accuracy of an automatic network analyzer

Puff, an Interactive Microwave Computer Aided Design Program for Personal Computers

We will demonstrate a CAD program designed for the lay out and analysis of microstrip circuits. The program runs on the IBM PC or AT. Circuit elements are selected from a parts list and drawn on the screen using the cursor keys. The analysis may then be performed, directly from the screen drawing. Puff has been used by microwave students in classes at the California Institute of Technology and the University of California at Los Angeles

CARBONIZED STARCH MICROCELLULAR FOAM-CELLULOSE FIBER COMPOSITE STRUCTURES

The production of microporous carbon foams from renewable starch microcellular foam-fiber (SMCF-Fiber) composites is described. Carbon foams are used in applications such as thermal insulation, battery electrodes, filters, fuel cells, and medical devices. SMCF-Fiber compos-ites were created from an aquagel. The water in the aquagel was exchanged with ethanol and then dried and carbonized. Higher amylose content starches and fiber contents of up to 4% improved the processability of the foam. The SMCF structure revealed agglomerates of swollen starch granules connected by a web of starch with pores in the 50-200 nanometer range. Heating the SMCF-fiber in a nitrogen atmosphere to temperatures between 350-700˚C produced carbon foams with a three-dimensional closed cell foam structure with cell diameters around 50 microns and pore walls around 1-3 microns. The stress versus strain compression data for carbonized samples displayed a linear elastic region and a plateau indicative of brittle crushing, typical of an elastic-brittle foam. The carbon foam products from these renew-able precursors are promising carbon structures with moderate strength and low density

Submillimeter-wave antennas on thin membranes

Submillimeter-wave antennas with bismuth microbolometer detectors have been fabricated on 1-μm thick silicon-oxynitride membranes. This approach results in better patterns than previous lens-coupled integrated circuit antennas, and eliminates the dielectric loss associated with the substrate lens. Measurements on a wideband log-periodic antenna at 700 GHz, 380 GHz and 167 GHz, and on a 700 GHz log-periodic imaging array, show no sidelobee and a 3-dB beamwidth between 40° and 50°. Also, the effective area can be increased by 5 dB by the use of a back-shorting mirror. Possible application areas are superconducting tunnel junction receivers for radio astronomy and imaging arrays for plasma diagnostics

Defining the Internet of Devices: Privacy and Security Implications

Presented at the 2014 Privacy Law Scholars Conference, hosted by the George Washington University Law School in Washington, DC, June 2014.What observers have called the Internet of Things (IoT) presents privacy and security challenges for contemporary society. The conceptual model of the IoT evolved rapidly from technologies used to track parts in industrial supply chain management to a diverse set of smart technologies. This rapid evolution has merged several conceptually distinct technologies into a single, difficult-to-define concept. A key difficulty is defining what constitutes a “thing.” The term has been used to refer both to the things sensed, such as a star or the contents of a refrigerator, and to the things that do the sensing (devices). We argue that the Internet of Things is better conceptualized as an Internet of Devices (IoD) because devices, not things, act in a digital form and connect to the Internet. Along with the other requirements of an effective IoD, technologists and policy makers must develop standards, network protocols, identity management solutions, and governance for the IoD to address privacy and security challenges a priori rather than retrofitted after the fact. Privacy and security cannot easily be added to a system that is already deployed and established. In this paper, we define the IoT and the IoD and summarize the independent technologies from which they have evolved. We provide a five-stage general policy framework for evaluating privacy and security concerns in the IoD. Our framework seeks to provide a consistent approach to evaluating privacy and security concerns across all IoD technologies while remaining flexible enough to adapt to new technical developments

Sequence Variation and Expression of the Gimap Gene Family in the BB Rat

Positional cloning of lymphopenia (lyp) in the BB rat revealed a frameshift mutation in Gimap5, a member of at least seven related GTPase Immune Associated Protein genes located on rat chromosome 4q24. Our aim was to clone and sequence the cDNA of the BB diabetes prone (DP) and diabetes resistant (DR) alleles of all seven Gimap genes in the congenic DR.lyp rat line with 2 Mb of BB DP DNA introgressed onto the DR genetic background. All (100%) DR.lyp/lyp rats are lymphopenic and develop type 1 diabetes (T1D) by 84 days of age while DR.+/+ rats remain T1D and lyp resistant. Among the seven Gimap genes, the Gimap5 frameshift mutation, a mutant allele that produces no protein, had the greatest impact on lymphopenia in the DR.lyp/lyp rat. Gimap4 and Gimap1 each had one amino acid substitution of unlikely significance for lymphopenia. Quantitative RT-PCR analysis showed a reduction in expression of all seven Gimap genes in DR.lyp/lyp spleen and mesenteric lymph nodes when compared to DR.+/+. Only four; Gimap1, Gimap4, Gimap5, and Gimap9 were reduced in thymus. Our data substantiates the Gimap5 frameshift mutation as the primary defect with only limited contributions to lymphopenia from the remaining Gimap genes

Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating

Globular clusters have proven to be essential to our understanding of many important astrophysical phenomena. Here we analyse spectroscopic observations of ten Halo globular clusters to determine their dark matter content, their tidal heating by the Galactic disc and halo, describe their metallicities and the likelihood that Newtonian dynamics explain their kinematics. We analyse a large number of members in all clusters, allowing us to address all these issues together, and we have included NGC 288 and M30 to overlap with previous studies. We find that any flattening of the velocity dispersion profiles in the outer regions of our clusters can be explained by tidal heating. We also find that all our GCs have M/L_V < 5, therefore, we infer the observed dynamics do not require dark matter, or a modification of gravity. We suggest that the lack of tidal heating signatures in distant clusters indicates the Halo is not triaxial. The isothermal rotations of each cluster are measured, with M4 and NGC 288 exhibiting rotation at a level of 0.9 +/- 0.1 km/s and 0.25 +/- 0.15 km/s, respectively. We also indirectly measure the tidal radius of NGC 6752, determining a more realistic figure for this cluster than current literature values. Lastly, an unresolved and intriguing puzzle is uncovered with regard to the cooling of the outer regions of all ten clusters.Comment: 12 pages, 8 figures, 1 table. Accepted for publication in MNRAS

Quantitative proteomics identify Tenascin-C as a promoter of lung cancer progression and contributor to a signature prognostic of patient survival

The extracellular microenvironment is an integral component of normal and diseased tissues that is poorly understood owing to its complexity. To investigate the contribution of the microenvironment to lung fibrosis and adenocarcinoma progression, two pathologies characterized by excessive stromal expansion, we used mouse models to characterize the extracellular matrix (ECM) composition of normal lung, fibrotic lung, lung tumors, and metastases. Using quantitative proteomics, we identified and assayed the abundance of 113 ECM proteins, which revealed robust ECM protein signatures unique to fibrosis, primary tumors, or metastases. These analyses indicated significantly increased abundance of several S100 proteins, including Fibronectin and Tenascin-C (Tnc), in primary lung tumors and associated lymph node metastases compared with normal tissue. We further showed that Tnc expression is repressed by the transcription factor Nkx2-1, a well-established suppressor of metastatic progression. We found that increasing the levels of Tnc, via CRISPR-mediated transcriptional activation of the endogenous gene, enhanced the metastatic dissemination of lung adenocarcinoma cells. Interrogation of human cancer gene expression data revealed that high TNC expression correlates with worse prognosis for lung adenocarcinoma, and that a three-gene expression signature comprising TNC, S100A10, and S100A11 is a robust predictor of patient survival independent of age, sex, smoking history, and mutational load. Our findings suggest that the poorly understood ECM composition of the fibrotic and tumor microenvironment is an underexplored source of diagnostic markers and potential therapeutic targets for cancer patients