Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analysed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies

Thermal degradation of Cross-Linked Polyisoprene and Polychloroprene

Polyisoprene and polychloroprene have been cross-linked either in solution or in solid state using free radical initiators. In the comparable experimental conditions higher cross-linking density was observed in the solid state process. Independent of the cross-linking method, polychloroprene tended to give a higher gel content and cross-link density than does polyisoprene. Infrared characterization of the cross-linked materials showed cis-trans isomerization occurred in the polyisoprene initiated by benzoyl peroxide, whereas no isomerization was found in the samples initiated by dicumyl peroxide. Polyisoprene does not cross-link by heating in a thermal analyzer, whereas polychloroprene easily undergoes cross-linking in such conditions. Infrared spectroscopy showed that in the case of polyisoprene, rearrangements occur upon heating which lead to the formation of terminal double bonds, while polychloroprene loses hydrogen chlorine which leads to a conjugated structure. There is apparently some enhancement of the thermal and thermal oxidative stability of polyisoprene because of the cross-linking. Cross-linked polychloroprene is less thermally stable than the virgin polymer. Cross-linking promotes polymers charring in the main step of weight loss in air, which leads to enhanced transitory char

Cytogenetic Studies of Normal and Cleft-Palate Epitheliums in Mice

This study investigated teratogenic activity on a cellular level through analysis of the cytogenetic complex in cleft-palate epithelial cells from the progenies of mice treated with cortisone. Analysis showed no detectable aberration from a normal chromosomal complement.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68120/2/10.1177_00220345690480041601.pd

Efficacy of a low-dose ferric-EDTA in reducing iron deficiency anaemia among underfive children living in malaria-holoendemic district of Mvomero, Tanzania

Iron deficiency anaemia is a public health problem in Tanzania especially among children under the age of five years. In malaria holoendemic areas, control of anaemia by supplementation with iron has been reported to increase serious adverse events. The World Health Organization recommends that, programs to control anaemia in such areas should go concurrently with malaria control programmes. The objectives of the study were to: (i) to determine if a supplement providing 2.5 mg of iron as ferric EDTA and 2.5 mg of iron as ferrous lactate (low dose) is as effective in correcting anaemia as a supplement providing the standard 10 mg of iron as ferrous lactate (high dose); and ii) determine if iron supplementation increased the risk of malaria. This study was carried out in Mvomero District of east-central Tanzania. Two groups (69 and 70 subjects per treatment) of moderately anaemic children (7.0–9.1 g of Hb/dl), received one of the two micronutrient supplements differing only in iron content for a period of 60 days. Results showed that, the average haemoglobin (Hb) concentration improved from 8.30±0.60 g/dl to 11.08±1.25 g/dl. The average weight-for-age for all children increased from 16.0 to 20.6% while their weight-for-height increased from 4.0 to 13.3%. The incidence of asymptomatic and symptomatic malaria ranged from 10.0 to 10.4% at all time points with no apparent increase in malaria severity due to iron supplementation. Overall, there was a significant reduction in anaemia during the 60 day supplementation period. This study demonstrated that, micronutrient supplements containing low-dose ferric-EDTA is just as effective as the high dose iron in reducing anaemia and can be safely utilized in malaria holoendemic areas to control iron deficiency anaemia. It is recommended that, a large study should be conducted to affirm the effectiveness of the low-dose ferric-EDTA in controlling iron deficiency anaemia among underfive children

Titanium sapphire : A decade of diode-laser pumping

For many years, Ti:sapphire was the prototypical example of a solid-state laser material that could not be diode pumped. The rationale for this assessment follows from the laser properties of Ti:sapphire, which combine to demand high brightness pumping in the blue-green region (see fig. 1 [1]). The development of efficient Gallium Nitride (GaN) based laser diodes eroded this logic [2], and improvements in the spatial brightness of GaN diode lasers subsequently enabled the first demonstration of a directly diode-laser pumped Ti:sapphire laser in 2009 [3], This presentation will outline the physics that makes diode-pumping difficult, and the developments that mean, it is, nonetheless, possible. Interestingly, diode-pumping of CW and modelocked Ti:sapphire lasers was achieved not by a radical redesign of the laser, but by careful optimisation of existing approaches that enabled the rapidly improving brightness of GaN diode lasers to be exploited [3-5]

IL-4 Signaling Drives a Unique Arginase\u3csup\u3e+\u3c/sup\u3e/IL-1β\u3csup\u3e+\u3c/sup\u3e Microglia Phenotype and Recruits Macrophages to the Inflammatory CNS: Consequences of Age-Related Deficits in IL-4Rα after Traumatic Spinal Cord Injury

Alternative activation of microglia/macrophages (M2a) by interleukin (IL)-4 is purported to support intrinsic growth and repair processes after CNS injury. Nonetheless, alternative activation of microglia is poorly understood in vivo, particularly in the context of inflammation, injury, and aging. Here, we show that aged mice (18-19 months) had reduced functional recovery after spinal cord injury (SCI) associated with impaired induction of IL-4 receptor α (IL-4Rα) on microglia. The failure to successfully promote an IL-4/IL-4Rα response in aged mice resulted in attenuated arginase (M2a associated), IL-1β, and chemokine ligand 2 (CCL2) expression, and diminished recruitment of IL-4Rα+ macrophages to the injured spinal cord. Furthermore, the link between reduced IL-4Rα expression and reduced arginase, IL-1β, and CCL2 expression was confirmed using adult IL-4Rα knock-out (IL-4RαKO) mice. To better understand IL-4Rα-mediated regulation of active microglia, a series of studies was completed in mice that were peripherally injected with lipopolysaccharide and later provided IL-4 by intracerebroventricular infusion. These immune-based studies demonstrate that inflammatory-induced IL-4Rα upregulation on microglia was required for the induction of arginase by IL-4. In addition, IL-4-mediated reprogramming of active microglia enhanced neurite growth ex vivo and increased inflammatory gene expression (i.e., IL-1β and CCL2) and the corresponding recruitment of CCR2+/IL-4Rα+/arginase+ myeloid cells in vivo. IL-4 reprogrammed active microglia to a unique and previously unreported phenotype (arginase+/IL-1β+) that augmented neurite growth and enhanced recruitment of peripheral IL-4Rα+ myeloid cells to the CNS. Moreover, this key signaling cascade was impaired with age corresponding with reduced functional recovery after SCI

Strain Accomodation in the Footwall of the Rubys Inn Thrust Fault, Hillsdale Canyon, Southern Utah

The Rubys Inn thrust fault in southern Utah has produced several styles of deformation in its footwall. This project describes four exceptionally well exposed examples of strain accommodation, including a mountain-scale, ductile footwall drag fold, cataclastic flexural slip between bedding surfaces of differing competencies, plastically deformed petrified wood within the zone of flexural slip, and cataclastic shear expressed as deformation bands. Such examples show how various lithologies can be deformed into a wide array of structures during a single deformation event. Furthermore, some of these structures result in changes in permeability, which are important for those interested in subsurface fluid flow

Bounds on the diameter of Cayley graphs of the symmetric group

In this paper we are concerned with the conjecture that, for any set of generators S of the symmetric group of degree n, the word length in terms of S of every permutation is bounded above by a polynomial of n. We prove this conjecture for sets of generators containing a permutation fixing at least 37% of the points.Comment: 17 pages, 6 table

The UK risk assessment scheme for all non-native species

1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa. 2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored. 3. Although designed for the UK, the scheme can readily be applied elsewhere