The perinatal mortality rate as an indicator of quality of care in international comparisons

Priming and recollection are expressions of human memory mediated by different brain events. These brain events were monitored while people discriminated words from nonwords. Mean response latencies were shorter for words that appeared in an earlier study phase than for new words. This priming effect was reduced when the letters of words in study-phase presentations were presented individually in succession as opposed to together as complete words. Based on this outcome, visual word-form priming was linked to a brain potential recorded from the scalp over the occipital lobe about 450 ms after word onset. This potential differed from another potential previously associated with recollection, suggesting that distinct operations associated with these two types of memory can be monitored at the precise time that they occur in the human brain.     

Growth of a human intestinal Desulfovibrio desulfuricans in continuous cultures containing defined populations of saccharolytic and amino acid fermenting bacteria

Ecological and physiological effects of the sulphate-reducing bacterium (SRB) Desulfovibrio desulfuricans on other intestinal organisms were investigated in anaerobic chemostats (dilution rate approximately 0.2 h-1). Reproducible defined bacterial communities were used in these experiments, comprising 14 different saccharolytic and amino acid fermenting species: Bifidobacterium longum, Bif. adolescentis, Bif. pseudolongum, Bif. infantis, Bacteroides thetaiotaomicron, Bact. vulgatus, Lactobacillus acidophilus, Enterococcus faecalis, Ent. faecium, Escherichia coli, Clostridium perfringens, Cl. butyricum, Cl. innocuum, Cl. bifermentans. Lactobacillus and Cl. bifermentans populations never rose above minimum detection limits (log10 2.0 and 4.0, respectively) under the experimental conditions employed in these studies. Inclusion of Des. desulfuricans in bacterial cultures (c. log10 8.4 viable cells ml-1) resulted in marked reductions (i.e. greater than 1 log) in planktonic cell population densities of several species, particularly Bif. longum, Cl. perfringens and Bif. pseudolongum. The two bacteroides species were unaffected by Des. desulfuricans, while numbers of Cl. butyricum increased. Extensive wall growth developed in the SRB culture, consisting mainly of Des. desulfuricans (log10 9.2 viable cells ml-1), Bact. thetaiotaomicron and Bact. vulgatus, with lesser numbers of facultative anaerobes, Cl. perfringens and Bif. longum. Wall growth was associated with a reduction in planktonic cell mass and increased acid production by the cultures. Chemotaxonomic study of chemostat microbiotas, on the basis of cellular fatty acid methyl ester (FAME) analyses, showed the existence of characteristic bacteroides (C15) and bifidobacterial (C18) markers, but desulfovibrio markers (i-C15:0, C16:0, i-C17:1) could be identified. The metabolic activities of saccharolytic organisms were altered in the SRB chemostat, including synthesis of a number of hydrolytic enzymes involved in carbohydrate breakdown, such as alpha-galactosidase, alpha-glucosidase and beta-galactosidase, together with several mucinolytic enzymes. High concentrations of sulphide (8.2 mmol 1-1) were detected in the SRB chemostat, suggesting that this metabolite may have been inhibitory to some species. Saccharolytic organisms growing in the SRB fermenter utilized more starch, but less galactose-containing polymers, which correlated with the observed glycosidase activities. Profound differences were also recorded with respect to fermentation product formation in the chemostats, where a major switch to acetate production occurred in the SRB culture, with concomitant reductions in propionate, butyrate and lactate, which is an important electron donor for desulfovibrios.     

Intrathyroidal parathyroid glands can be a cause of failed cervical exploration for hyperparathyroidism

BACKGROUND: The incidence of intrathyroidal parathyroid glands remains controversial. The purpose of this study was to determine the incidence in a series of patients with hyperparathyroidism. METHODS: Three hundred nine patients underwent parathyroidectomy. Patients were divided into two groups: uniglandular disease versus hyperplasia. RESULTS: Eighteen of 309 patients (6%) had abnormal intrathyroidal parathyroid glands. The incidence was 3% (7 of 222) in patients with uniglandular disease versus 15% (11 of 73) in those with hyperplasia. With a mean follow-up of 54 months, 12 patients are eucalcemic, 5 have persistent hypocalcemia, and 1 has recurrent hypercalcemia. There were no recurrent laryngeal nerve injuries. CONCLUSIONS: These data suggest that an intrathyroidal adenoma is an uncommon cause of failure, whereas abnormal intrathyroidal parathyroid tissue may be a more common cause of failure in patients with hyperplasia.     

Factors Influencing the Adhesion of Microorganisms to Surfaces

Starvation, growth phase, and carbon source influenced bacterial cell surface hydrophobicity. Both the number and kind of microorganisms that colonized metal surfaces depended on the type of metal and the presence of an imposed electrical potential. No significant differences in attachment and growth of a pure culture were observed when metal surfaces were dipped in an exogenous energy source. The chemical composition of naturally occurring adsorbed organic films on metal surfaces was shown to be independent of surface composition and polarization.     

Nanocolumnar Preferentially Oriented PSZT Thin Films Deposited on Thermally Grown Silicon Dioxide

We report the first instance of deposition of preferentially oriented, nanocrystalline, and nanocolumnar strontium-doped lead zirconate titanate (PSZT) ferroelectric thin films directly on thermal silicon dioxide. No intermediate seed or activation layers were used between PSZT and silicon dioxide. The deposited thin films have been characterised using a combination of diffraction and microscopy techniques.     

Comparison of N-Heterocyclic Aromatics Dibenzo[c,g]Carbazole and Dibenz[a,j]Acridine : Metabolism,DNA Binding and Mutation

N-Heterocyclic aromatics, such as carbazole and acridine derivatives, are environmental carcinogenic pollutants. Examples of these compounds are 7H-dibenzo[c,g]carbazole (DBC) and dibenz[a,j]acridine (DBA). The ionization potential (IP) for DBC is lower than for DBA. DBC is metabolized in lung and liver by way of phenols or directly through radical cations. DBC-induced liver and lung tumors have mutations in the 61^st codon of ras. DBA is metabolized in skin by way of a diol-epoxide of DBA. DBA-induced skin tumors have mutations in 12^th, 13^th and 61^st codons of ras. In summary, the metabolic activation of DBC proceeds through different adduction pattern pathways than does DBA and leads to different ras mutational spectra.     

Adhesion of CPO onto high modulus TPO: Lap-shear tests in conjunction with microscopy studies of the fracture surface structure

A lap-shear test was employed to investigate the failure mechanism of a chlorinated polyolefin (CPO) coating on a high-modulus thermoplastic olefin (TPO) substrate fabricated as a blend of a highly crystalline Ziegler-Natta isotactic polypropylene (iPP) and a crystalline metallocene poly(ethylene-butene) (9 wt% butene, EB9) impact modifier. The CPO was a chlorinated polypropylene containing 20 wt% Cl. The results showed that the fracture strength increased with increasing EB9 content in TPO blends. They also showed that the presence of xylene vapor during the bake step improved the adhesion between CPO and iPP itself (by 40%), but had a much smaller effect for the TPOs. Optical and transmission electronic microscopy images revealed a well-defined skin layer approximately 230 μm thick at the mold surface of the injection molded substrates. For the 25 wt% EB9 blend (TPO₂₅), this skin layer consists of thin fibers of EB trapped in a transcrystalline iPP matrix, with crystalline lamellae propagating from the matrix across the EB9 domains. Laser scanning confocal fluorescence microscopy (LCFM) and scanning electron microscopy images of iPP/CPO/iPP samples indicate that failure occurred close to the interface between the CPO and the iPP substrate, and, during fracture, the CPO layer maintained its original thickness. For the TPO/CPO/TPO sandwich samples, the fracture surfaces themselves were much rougher than that between CPO and iPP. Substantial deformation of the CPO layer was seen in the fractured samples, and failure was due primarily to cohesive fracture of the CPO in the region adjacent to the TPO substrate. From the perspective of newly introduced environmental regulations restricting aromatic hydrocarbons in automotive coatings, the most important result was the strong adhesion between CPO and TPO₂₅, with little difference between the samples exposed to xylene vapor and those not exposed to xylene.     

Magnetic resonance studies of cement based materials in inhomogeneous magnetic fields

Single-sided magnets give hope that Nuclear Magnetic Resonance (NMR) might in future be used for in situ characterisation of hydration and water transport in the surface layers of concrete slabs. Towards that end, a portable NMR-MOUSE (MObile Universal Surface Explorer) has been used to follow the hydration of gypsum based plaster, a Portland cement paste and concrete mortar. The results compare favourably to those obtained using a standard laboratory bench-top spectrometer. Further, stray field imaging (STRAFI) based methods have been used with embedded NMR detector coils to study water transport across a mortar/topping interface. The measured signal amplitudes are found to correlate with varying sample conditions.     

Cl electrosorption on Ag(1 0 0): Lateral interactions and electrosorption valency from comparison of Monte Carlo simulations with chronocoulometry experiments

We present Monte Carlo simulations using an equilibrium lattice-gas model for the electrosorption of Cl on Ag(1 0 0) single-crystal surfaces. Fitting the simulated isotherms to chronocoulometry experiments, we extract parameters such as the electrosorption valency γ and the next-nearest-neighbor lateral interaction energy ϕ_nnn. Both coverage-dependent and coverage-independent γ were previously studied, assuming a constant ϕ_nnn [I. Abou Hamad, Th. Wandlowski, G. Brown, P.A. Rikvold, J. Electroanal. Chem. 554–555 (2003) 211]. Here, a self-consistent, entirely electrostatic picture of the lateral interactions with a coverage-dependent ϕ_nnn is developed, and a relationship between ϕ_nnn and γ is investigated for Cl on Ag(1 0 0).     

Effect of a coalescing aid on the earliest stages of polymer diffusion in poly(butyl acrylate-co-methyl methacrylate) latex films

In this article we use fluorescence resonance energy transfer (FRET) to investigate how a classic coalescing aid, such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Texanol?) (TX), acts on the earliest stages of polymer diffusion as the latex film is still drying. In our approach, we temporarily arrest the drying process of a partially wet latex film by sealing it in an airtight chamber previously cooled to near the latex T_g. At these conditions, we are able to effectively stop the drying process and the polymer diffusion. FRET measurements at various locations on such a sample provide us information about the mechanism operating at the initial stages of polymer diffusion as the latex film is still drying. We complete our study with FRET measurements carried out at longer aging times on predried latex films. We analyze our diffusion data in terms of free volume theory and propose a mechanism that can account for the results obtained.