Lanthanum hexaaluminate—a new material for atmospheric plasma spraying of advanced thermal barrier coatings

One of the main application fields of the thermal spraying process is thermal barrier coatings (TBCs). Today, partially stabilized zirconia (YSZ or MSZ) is mainly used as a TBC material. At temperatures above 1000 °C, zirconia layers age distinctively, including phenomena shrinkage and microcrack formation. Therefore, there is a considerable interest in TBCs for higher temperature applications. In this paper, lanthanum hexaaluminate, a newly developed TBC material with long-term stability up to 1400 °C, is presented. It ages significantly more slowly at these high temperatures than commercial zirconia-based TBCs. Its composition favors the formation of platelets, which prevent a densification of the coating by postsintering. It consists of La₂O₃, Al₂O₃, and MgO. Its crystal structure corresponds to a magnetoplumbite phase. Lanthanum hexaaluminate powders were produced using two different fabrication routes, one based on salts and the other one based on oxides. To optimize the granulate, various raw materials and additives were tested. The slurry was spray dried in a laboratory spray drier and calcined at 1650 °C. Using these two powders, coatings were produced by atmospheric plasma spraying (APS). The residual stresses of the coatings were measured by the hole drilling method, and the deposition process was optimized with respect to the residual stresses in the TBC. The coatings were extensively analyzed regarding phase composition, thermal expansion, and long-term stability, as well as microstructural properties.     

Gastric pacing improves emptying and symptoms in patients with gastroparesis

BACKGROUND & AIMS: No effective treatment is available for patients with gastroparesis refractory to standard medical therapy. The aim of this study was to investigate the effects of gastric pacing on gastric electrical activity, gastric emptying, and symptoms in patients with gastroparesis. METHODS: Nine patients with gastroparesis participated in this study. Four pairs of cardiac pacing wires were implanted on the serosa of the stomach. The protocol consisted of two portions: a temporary inpatient study period and an outpatient study for a period of 1 month or more. RESULTS: Gastric pacing entrained the gastric slow wave in all subjects and converted tachygastria in 2 patients into regular 3-cpm slow waves. Gastric emptying was significantly improved after the outpatient treatment with gastric pacing. The gastric retention at 2 hours was reduced from 77.0% +/- 3.3% to 56.6% +/- 8.6% (P < 0.05). Symptoms of gastroparesis were substantially reduced at the end of the outpatient treatment (1.51 +/- 0.46 vs. 2.84 +/- 0.61; P < 0.04). Eight of 9 patients no longer relied on jejunostomy tube feeding, and no adverse events were noted related to the pacing unit. CONCLUSIONS: Gastric pacing seems to be able to improve symptoms of gastroparesis and to accelerate gastric emptying in patients with gastroparesis. More controlled studies are necessary to further investigate the role of gastric pacing in clinical practice.     

Denaturation and reactivation of dimeric human glutathione reductase--an assay for folding inhibitors

In response to a Department of Health, England, circular encouraging policies of named voluntary antenatal HIV antibody testing, one West Midlands health authority in England introduced a policy of raising the issue proactively at the first antenatal attendance. In order to facilitate this policy a short staff education programme was provided for midwives. This paper reports on part of a study which aimed to evaluate the impact of the HIV awareness training programme. A sample of midwives (n = 65) was randomly selected for inclusion in the study. Thirty-three had attended training and 32 had not. Data were collected using a self-administered questionnaire exploring knowledge of aetiology of HIV/AIDS, knowledge of transmission, knowledge of obstetric and paediatric HIV, attitudes to HIV, issues related to antenatal HIV antibody testing and opinions about the HIV awareness training programme. Results indicated no significant difference in levels of knowledge or in attitude between those who had attended the training programme and those who had not. Similarly, no significant difference was found in terms of how midwives would react to women requesting HIV antibody testing. Many of the results contradict the current literature and as a conclusion it is suggested that there is a need to review HIV-related training for midwives.     

On-line coupling of micellar electrokinetic chromatography to electrospray mass spectrometry

The possibility of selectivity enhancement in capillary electrophoresis-mass spectrometry (CE-MS) by hyphenating micellar electrokinetic chromatography (MEKC) and electrospray mass spectrometry (MS) is described for two quaternary ammonium compounds. Direct coupling of MEKC to MS is hazardous because of the contamination of the ion source due to presence of an excess of micelle forming agent in the MEKC buffer. Therefore, a coupled-capillary setup with the possibilities of voltage switching and buffer renewal has been designed. Such a system allows on-line heartcutting of the zones of interest in the MEKC capillary with subsequent transfer via a second capillary to the mass spectrometer.     

Economic reduction of refuse in the hospital

The effects are described of adding either the dried fruiting bodies of the oyster fungus Pleurotus ostreatus, or an ethanolic extract of it, to the diet of normal Wistar male rats and a strain with hereditary hypercholesterolaemia. Addition of the dry oyster fungus to the diet significantly increased, by more than two-fold, the triacylglycerol (TAG) level in the plasma of both groups of rats compared with their respective controls. In contrast, the ethanolic extract did not significantly change TAG levels. Values for total cholesterol and its high- and low-density lipoprotein fractions in the plasma, as well as the calculated atherogenic index, did not show any significant change. Levels of liver cholesterol were significantly lowered by the dried oyster fungus in both hypercholesterolaemic and normal groups of rats, and by the ethanolic extract in normal rats. A significantly increased phospholipid-to-cholesterol ratio in the aortas of both groups of rats, after the administration of either dried oyster fungus or the ethanolic extract of it, suggests a favourable anti-atherogenic effect for both.     

Cytomorphological features, AgNOR counts and c-erb B-2 in carcinoma breast

The present study was designed to evaluate the cytomorphological features (nuclear grade and smear pattern) and AgNOR counts in 60 cases of carcinoma breast. The smears were stained with May Gruenwald Giemsa (MGG) and Papanicolaou stains. Silver staining nucleolar organiser region (AgNOR) counts and c-erb B-2 immunostaining were also done in each case. The smear pattern was assessed and classified as 'typical', 'cluster predominant' or 'individual cell type', and the nuclei were graded as grade I, II or III. Smear pattern and nuclear grade were found to be related variables. A significant association was found between nuclear grade and AgNOR counts (p = 0.03). Also postmenopausal women had statistically significant higher nuclear grades and less cohesive cell clusters as compared to premenopausal women. Twenty-three carcinoma breast were positive for c-erb B-2, of these 14 were postmenopausal women.     

Biodegradation of polyhydroxyalkanoic acids

Stimulated by the commercial availability of bacteriologically produced polyesters such as poly[(R)-3-hydroxybutyric acid], and encouraged by the discovery of new constituents of polyhydroxyalkanoic acids (PHA), a considerable body of knowledge on the metabolism of PHA in microorganisms has accumulated. The objective of this essay is to give an overview on the biodegradation of PHA. The following topics are discussed: (i) general considerations of PHA degradation, (ii) methods for identification and isolation of PHA-degrading microorganisms, (iii) characterization of PHA-degrading microorganisms, (iv) biochemical properties of PHA depolymerases, (v) mechanisms of PHA hydrolysis, (vi) regulation of PHA depolymerase synthesis, (vii) molecular biology of PHA depolymerases, (viii) influence of the physicochemical properties of PHA on its biodegradability, (ix) degradation of polyesters related to PHA, (x) biotechnological aspects of PHA and PHA depolymerases.     

Methods of Antibiotic Applications as Related to Microbial Quality of Lamb by PCA and Bioluminescence

The effects of different methods of application of chlortetracycline and oxytetracycline on microbial properties of lamb meat were studied. A significant antibacterial effect of antibiotic was found on total mesophilic bacteria count. The mesophilic bacteria level was determined by two methods: the conventional method using Plate Count Agar and bioluminescence. Correlation curves of the CFU and RLU values proved two methods were highly related. Thus for the microbiology quality of meat hygiene the bioluminescence method may be used as a fast and alternative method to PCA. Note that bioluminescence requires a higher degree of skill and attention.