Hospital practices influence the pattern of infective endocarditis

OBJECTIVE: To identify factors contributing to infective endocarditis at a major teaching hospital. METHODS: Retrospective review of clinical records of patients diagnosed with endocarditis by standard case definitions with respect to causative organisms, clinical features and outcome. RESULTS: One hundred and ninety-three episodes of endocarditis seen between 1979 and 1992 at Westmead Hospital, Sydney, were reviewed. In the 174 cases where the causative organism was isolated, 75 (43%) were Staphylococcus aureus and 50 (29%) were viridans streptococci. Nosocomial acquisition and/or inter-hospital transfer accounted for 83 episodes; 48 (58%) S. aureus (P < 0.001) and nine (11%) viridans streptococci (P < 0.001). In cases from the local community, viridans streptococci were more common than S. aureus (37% versus 25%); these included 18 episodes (14 S. aureus) in intravenous drug users. CONCLUSION: We conclude that, compared with community-acquired infections, the aetiology of endocarditis in a large teaching hospital is influenced strongly by the prevalence of nosocomial endocarditis and the need for interhospital transfer of complicated cases.     

Grain Boundary Diffusion of Magnesium in Zirconia

This paper reports the transport kinetics of Mg in cubic yttria-stabilized zirconia (containing 10% mol of Y₂O₃ (10YSZ)) involving the bulk and the grain boundary diffusion coefficients. The diffusion-controlled concentration profiles of Mg were determined using secondary ion mass spectrometry (SIMS) in the range 1073–1273 K. The determined bulk diffusion coefficient and the grain boundary diffusion product may be expressed as the following functions of temperature, respectively: D = 5.7 exp[(−390 kJ/mol)/ RT ] cm²·s⁻¹ and D 'αδ= 3.2 × 10⁻¹⁵ exp[(−121 kJ/mol)/ RT ] cm³·s⁻¹, where α is the segregation enrichment factor and δ is the boundary layer thickness. The grain boundary enhancement factor decreases with temperature from 10⁵ at 1073 K to 10³ at 1273 K.     

Effects of Different Boron Compounds on the Corrosion Resistance of Andalusite-Based Low-Cement Castables in Contact with Molten Al Alloy

Interfacial reactions between Al alloy and andalusite low-cement castables (LCCs) containing 5 wt pct B₂O₃, B₄C, and BN were analyzed at 1123 K and 1433 K (850 °C and 1160 °C) using the Alcoa cup test. The results showed that the addition of boron-containing materials led to the formation of aluminoborate (9Al₂O₃.2B₂O₃) and glassy phase containing boron in the prefiring temperature (1373 K [1100 °C]), which consequently improved the corrosion resistance of the refractories. The high heat of formation of the aluminoborate phase (which increased its stability to reactions with molten Al alloy) and the low solubility of boron in molten Al were the major factors that contributed to the improvement in the corrosion resistance of B-doped samples.     

Missing carbon reductions? Exploring rebound and backfire effects in UK households

Households are expected to play a pivotal role in reducing the UK's greenhouse gas (GHG) emissions, and the UK Government is encouraging specific household actions to help meet its targets. However, due to the rebound effect, only a portion of the GHG emission reductions estimated by simple engineering calculations are generally achieved in practice. For example, replacing short car journeys by walking or cycling reduces consumption of motor fuels. But this frees up money that may be spent on, for example, purchasing extra clothes or flying on vacation. Alternatively, the money may be put into savings. Since all of these options lead to GHG emissions, total GHG savings may be less than anticipated. Indeed, in some instances, emissions may increase—a phenomenon known as ‘backfire’. We estimate that the rebound effect for a combination of three abatement actions by UK households is approximately 34%. Targeting re-spending on goods and services with a low GHG intensity reduces this to a minimum of around 12%, while re-spending on goods and services with a high GHG intensity leads to backfire. Our study highlights the importance of shifting consumption to lower GHG intensive categories and investing in low carbon investments.     

Color Tunable Poly (N‐Isopropylacrylamide)‐co‐Acrylic Acid Microgel–Au Hybrid Assemblies

A new class of materials that are capable of color tunability over 300 nm with a 15 °C temperature change is introduced. The materials are assembled from thermoresponsive poly (N‐isopropylacrylamide)‐co‐acrylic acid (pNIPAm‐co‐AAc) microgels, which are deposited on Au coated glass substrates. The films are also pH responsive; the temperature‐induced color change was suppressed at high pH and is consistent with the behavior of a solution of suspended microgels. The mechanism proposed to account for the observed optical properties suggests that they result from the two Au layers being separated from each other by the “monolithic” microgel film, much like a Fabry‐Pérot etalon or interferometer. It is the modulation of the distance between these two layers, facilitated by the microgel collapse transition at high temperature, that allows the color to be tuned. The sensitivity of the system presented here will be used for future sensing and biosensing applications, as well as for light filtering applications.     

Microwave systems design for high-performance moving targetindicators in radars

Clutter cancellation of 65 dB and better is directly proportional to good radar stability, and since many hardware areas produce instabilities at various levels, the architecture of a radar requires special design considerations to support this high stability. The noise character and generation methods of these instabilities in the various hardware areas are described, and design solutions are given to eliminate them. Microwave delay line, a reliable, accurate method of measuring radar stability in L- and S-band radars, is described. The longest microwave delay line available for use at L -band and S-band frequencies is a 15-μs sapphire bulk acoustic wave (BAW) delay line. For higher-frequency radars, smaller delays must be used to keep the insertion loss down to a usable level. The question is raised as to the adequacy of this delay time to provide sufficient visibility for stability measurements of the stable noise. For transmitter measurements, it is adequate for the more common pulse widths, which are less than 15 μs. For LO measurements, the analysis shows that this delay does provide sufficient decorrelation for accurate LO noise measurements     

Manufacturability issues in rapid thermal chemical vapor deposition

Rapid thermal processing (RTP) has been considered from a manufacturing point of view as a potential technology for depositing thin films by low-pressure chemical vapor deposition (LPCVD) in a single-wafer manufacturing environment. The results of this study suggest that new chemical processes must be developed to satisfy the throughput requirements of single-wafer manufacturing and the demands of cold-wall reactor design. Issues such as temperature measurement and uniformity are reviewed and reconsidered in the context of LPCVD. New tool requirements for reduced pressure operation are discussed. New advances in tool design are needed (especially in temperature measurement) before rapid thermal chemical vapor deposition (RTCVD) can be considered as a routine manufacturable process