Coexisting hyperplastic antral polyp and hypertrophic pyloric stenosis

This report describes a child with hypertrophic pyloric stenosis with persistent vomiting after pyloromyotomy due to a coexistent hypertrophic antral polyp.     

Temperature uniformity in RTP furnaces

The heat transfer to a wafer in a rapid thermal processing (RTP) furnace is simulated by an analytical/numerical model. The model includes radiation heat transfer to the wafer from the lamps, heat conduction within the wafer, and emission of radiation from the wafer. Geometric optics are used to predict the radiant heat flux distribution over the wafer. The predicted wafer surface temperature distribution is compared to measurements made in an RTP furnace for two different reflector geometries. Lamp configurations and the resulting irradiance required to produce a uniform wafer temperature are defined     

Brain scanning with the Anger multiplane tomographic scanner as a second examination evaluation by the ROC method

The disposition kinetics and systemic availability of ketamine, a dissociative anaesthetic agent, was studied in normal domestic cats. A similar dose (25 mg/kg) of ketamine hydrochloride was administered by the i.v. and i.m. routes; drug concentrations in plasma were measured by a gas-liquid chromatographic procedure. A rapid distribution phase (t1/2 (alpha) = 3 min) was followed by a slower first-order elimination phase. The half-life of the drug (66.9 +/- 24.1 min) was independent of the route of parenteral administration. Absorption from i.m. site of administration was rapid, with peak plasma level at 10 min, and ca. 92 per cent of the dose was available systemically. Extent of plasma protein binding, measured in vitro at 5 and 20 mug/ml by equilibrium dialysis technique, was 53 per cent and independent of ketamine concentration. Simulated plasma and tissue level curves, which were generated by an analogue computer programmed with the individual rate constants of the two-compartment open model, showed that 10 and 15 per cent of the dose were present in the central and peripheral compartments, respectively, at 90 min after i.v. administration of the drug. Peak tissue level of 42 per cent of the dose was reached at 12 to 15 min. Parenteral administration of ketamine, at the dosage rate studied, quickly produced an immobilizing effect of variable duration (0.75 to 1.75 hr) in normal cats.     

Catalytic oxidation with air of tartronic acid to mesoxalic acid on bismuth-promoted platinum

Mesoxalic acid (ketomalonic acid) was prepared by oxidative dehydrogenation with air of tartronic acid in aqueous solution on carbon-supported platinum-bismuth catalysts. By increasing the pH, using a higher catalyst/substrate ratio or increasing the temperature, higher yields could be obtained (maximum yield obtained of 65% at 80% conversion). The results obtained for this reaction and for the analogous catalytic oxidations of glyceric acid to hydroxypyruvic acid, and lactic acid to pyruvic acid, enabled a general reaction mechanism to be proposed for the selective oxidation of α-hydroxy acids to α-keto acids on platinum-bismuth catalysts. This revised version was published online in July 2006 with corrections to the Cover Date.     

Polymer molecular weight and chain transfer during the photopolymerization of an aliphatic monoacrylate in a smectic liquid crystal

Polymer/liquid crystal (LC) composites offer a unique opportunity to study polymerizations in ordered media, specifically the potential effect mesophase order can have on polymer properties including molecular weight. To develop successful polymer/LC composites for display applications, it is important to understand the effect of mesophase order on polymer molecular weight in order to optimize the electro-optic (EO) properties of the polymer/LC composite. Polymer molecular weight may be influenced in a LC by changes in polymerization rate as LC order is modulated and by chain transfer. This work focuses on the photopolymerization of an aliphatic monoacrylate monomer, decyl acrylate (DA), both in the ordered LC phases of 8CB as well as in isotropic solutions with LC and co-solvent.When DA is polymerized using the LC as the solvent, enhanced polymerization rates and polymer molecular weights are observed in the highly ordered smectic phase compared to the less ordered nematic and isotropic phases. When conducted strictly in an isotropic environment using a co-solvent with increasing 8CB percentages, a dramatic decrease in the polymerization rate and a significant reduction of the polymer molecular weight is observed, implying degradative chain transfer to the LC. NMR results show that this chain transfer is a result of hydrogen abstraction from the liquid crystals, which leads to the reduction in the polymerization rate with increasing 8CB concentration. The most likely site of hydrogen abstraction is from the benzyl hydrogens of the alkyl chain of 8CB. This chain transfer also plays a role for polymerizations performed in the ordered phases of the LC. Chain transfer appears to be less significant when polymerizations are conducted in the smectic phase due to the anti-parallel association of the LC molecules. When polymerizations occur in the less ordered phases, chain transfer dominates leading to a large reduction in polymer molecular weight and polymerization rate.     

Modeling planar arbitrarily shaped microstrip elements inmultilayered media

Microstrip elements of arbitrary shape are modeled in multilayered media. The Green's function for the multilayered structure is developed in a form useful for efficient computation for interacting microstrip elements, which may be located at any substrate layer and separated by an arbitrarily large distance. This result is of significant value to a variety of applications in wave propagation besides those discussed in this paper. The mixed-potential integral-equation (MPIE) method is developed in the spatial domain. Examples for regularly/arbitrarily shaped geometries in single and multilayered media are presented. These involve the optimization of an open-end microstrip, a radial-stub microstrip, a five-section overlay-gap-coupled filter, and a circular-patch proximity-coupled microstrip antenna. Very good agreement with measurement and other published data is observed     

A suggested methodology for the construction of national bone densitometry reference ranges: 1372 Caucasian women from four UK sites

This paper presents a simple methodology for combining bone densitometry data from different sites in the UK, having instruments from the same manufacturer (LUNAR Radiation). Additive normalization factors were used on all data prior to inclusion in a reference database which ultimately included data on 1372 Caucasian women, aged 20-70 years, of whom 749 were post-menopausal. Reference data for spine (L2-L4) and femoral neck bone mineral density are given in tabular form as 3 year moving averages for: (1) all women; (2) perimenopausal women grouped by menopausal status; and (3) post-menopausal women with respect to years since menopause. These data may be used to construct Z-score. T-score or percentile reporting ranges and may be adopted as the core for a UK reference range.     

The effect of gas composition and contaminants on the lifetime of surface‐treated FeCrAlRE alloys

The degradation of a variety of alumina‐forming Fe20Cr5Al based alloys has been investigated at temperatures ranging from 1100°C to 1300°C for up to 4000 h (100 h/cycle) in different oxidising environments such as laboratory air, air + 10 vol% H₂O, air + 60 vol% H₂O and simulated automotive exhaust gas. Seven model alloys with controlled levels of impurities such as P, S and C and carefully controlled levels of additional elements (Y, Zr, Ti, Hf, Si, La, etc.) and two different commercial alloys (Aluchrom YHfAl and Kanthal APMT) were chosen for this study. The investigation showed that the model alloys containing La, Y + Si and Y with added C, and the commercial alloy APMT usually had the lowest initial oxidation growth rates, whereas model alloys containing Y plus Zr, and the commercial alloy YHfAl had the higher oxidation rates regardless of the different oxidising environments. Scale spallation was more prevalent in the case of alloys with low oxide growth rates but changing the levels of water vapour in the oxidising atmospheres had only a minor influence on the degree of spallation or the oxide morphology. The scales formed on the alloys containing La, Y + Si and high C spalled in an adhesive manner (at the scale/metal interface), whereas scales formed on alloys containing Y plus Hf, Zr or Ti cracked and spalled in a cohesive manner (within the scale). Inhomogeneities in the distribution of the alloying additions led to greater changes in the oxide morphologies than any difference in oxidising atmosphere, but the crystallographic textures of all the oxides were similar. This pilot study enabled us to rank the alloys according to their resistance to spallation and also to determine the influence of minor elements when added as tightly controlled single or multiple element additions. Some of these alloys were then used as mechanically weak PVD coatings on a strong (APMT) substrate, and further oxidation experiments confirmed that the coatings then oxidised in a similar way to the bulk alloys.     

A survey of depressive symptoms among Vietnamese-American men in three locales: prevalence and correlates

Adolescent health problems are often undetected in physicians' offices. The Dartmouth Primary Care Cooperative Information Project has developed a validated and reliable approach to identify adolescent health problems and initiate education in a school setting. A self-administered, anonymous, 26-item questionnaire was given to 204 students in a rural high school. Responses were scanned into PC-based software. Within one working day students were given individualized letters identifying their problem health issues as detected by the questionnaire and recommendations for education. Ninety-nine percent of students participated. Six weeks later 49% of a sample of 41 students reported reading the information and 50% planned to change behavior. This standardized, validated strategy of adolescent health assessment, feedback, and education was feasible for use in schools. The school responded to the data by employing a psychologist to address mental health needs.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹