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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1333-1338 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two possible types of cadmium sulphide (CdS) nanostructures can be formed within Langmuir–Blodgett (LB) films of calixarene Cd salt as a result of exposure to H2S gas: nanoclusters with the size of about 1.5 nm or two-dimensional planes with the thickness of about 1.7 nm. Transmission electron microscopy and electron diffraction studies on calixarene/CdS LB films show that CdS particles are not present in the fresh samples at the beginning, but they are gradually formed under exposure to a high energy electron beam. A blueshift of the first exciton absorption band and an increase of the extinction coefficient, caused by exposure to H2S gas, were found with UV-visible optical spectroscopy and surface plasmon resonance, respectively. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Long-term adrenalectomy (ADX) is associated with marked down-regulation of pituitary corticotropin releasing factor type-1 receptors (CRF-R1) but normal CRF-R1 mRNA levels, suggesting that regulation of receptor levels occurs at post-transcriptional sites. We have reported that adrenal cytosolic proteins, which bind to cis elements in the 5′ leader sequence (5′LS) of the rat angiotensin II type 1a receptor (AT1aR) mRNA, participate in the regulation of AT1aR density by inhibiting AT1aR mRNA translation. In this study, we examined anterior pituitary cytosolic proteins that form RNA protein complexes (RPC) with the 5′LS of the CRF-R1 and the AT1aR. Competition studies and ultraviolet-crosslinking analysis suggest that formation of CRF-R1 and AT1aR 5′LS RPC require at least some proteins that are common to both receptor mRNAs. Pituitaries isolated from male Sprague-Dawley rats six days after ADX showed significant (P 〈 0.05) increases of 2.9-fold in CRF-R1 5′LS RNA binding protein (BP) activity compared to pituitaries from sham-operated rats; this effect of ADX was prevented by glucocorticoid replacement. By contrast, no differences in the number of pituitary AT1aR binding sites or pituitary AT1aR 5′LS BP activity were observed between sham and ADX rats, indicating that the effect of ADX on RPC formation was specific for CRF-R1 mRNA. Addition of pituitary cytosolic extracts inhibited in vitro translation of CRF-R1 mRNA by 79% under conditions that had no significant effects on the translation of a control mRNA. The data suggest that CRF-R1 translation is regulated by modulation of the HPA axis through pituitary cytosolic proteins binding to the CRF-R1 5′LS.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study aimed to elucidate development of the areola in the early dromedary placenta in comparison with that of the pig and mare. Placental tissues from 25 pregnant camels were obtained from Cairo abattoir and prepared for light, scanning and transmission electron microscopy by routine methods. Vascular casts were made by injection of 4 : 1 liquid plastic mixture of mercox and methylmethacrylate. Areolar formation was first observed at 4.5 cm curved-crown-rump CVR length, while by 5–9 cm CVR length, the endometrial surface was uneven and studded with numerous uterine gland openings, where corresponding foetal areolae were barely detectable and the foetal areolar cells were of variable appearance and covered with long microvilli. At 10–13 cm CVR length the uterine gland openings developed irregular folds and the maternal areolar cells showed numerous apical blebs. At 14–29 cm CVR length the foetal areolae showed a great increase in height at the expense of their width. At 30–34 cm (CVR) length the maternal areolae appeared discoid and sharply demarcated from the surrounding inter-areolar tissues and the foetal areolae were rounded to irregular in shape with well-developed areolar rims. The vascular casts showed a widely meshed capillary network on the maternal areola, connecting with the pre- and post-capillary vessels, whereas the foetal side showed a relatively dense capillary meshwork. These studies indicate that the areola in the placenta of the one-humped camel is of the regular type like in the pig, and is poorly vascularized.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Information management & computer security 11 (2003), S. 130-138 
    ISSN: 0968-5227
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Computer Science
    Notes: As the Internet revolution moves into full swing, those countries that have not embraced e-commerce technology will face new hurdles as they seek to develop their economies. Standing in the path of these countries' attempts to adapt e-commerce technologies are several key issues that can be broadly defined as trust barriers. Rather than think of the trust issues as barriers one must think of them as assets. Presents a conceptual model and framework that highlight the key factors in business trust relationships within developing countries; information security, technical and industrial infrastructure, education, government, and socio-cultural factors. These factors are considered in the light of different types of e-commerce business transactions taking place within and across borders such as business-to-business (B2B), business-to-consumer (B2C), consumer-to-business (C2B), and consumer-to-consumer (C2C).
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Stochastic environmental research and risk assessment 14 (2000), S. 428-448 
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract.  An efficient numerical solution for the two-dimensional groundwater flow problem using artificial neural networks (ANNs) is presented. Under stationary velocity conditions with unidirectional mean flow, the conductivity realizations and the head gradients, obtained by a traditional finite difference solution to the flow equation, are given as input-output pairs to train a neural network. The ANN is trained successfully and a certain level of recognition of the relationship between input conductivity patterns and output head gradients is achieved. The trained network produced velocity realizations that are physically plausible without solving the flow equation for each of the conductivity realizations. This is achieved in a small fraction of the time necessary for solving the flow equations. The prediction accuracy of the ANN reaches 97.5% for the longitudinal head gradient and 94.7% for the transverse gradient. Head-gradient and velocity statistics in terms of the first two moments are obtained with a very high accuracy. The cross covariances between head gradients and the fluctuating log-conductivity (log-K) and between velocity and log-K obtained with the ANN approach match very closely those obtained by a traditional numerical solution. The same is true for the velocity components auto-covariances. The results are also extended to transport simulations with very good accuracy. Spatial moments (up to the fourth) of mean-concentration plumes obtained using ANNs are in very good agreement with the traditional Monte Carlo simulations. Furthermore, the concentration second moment (concentration variance) is very close between the two approaches. Considering the fact that higher moments of concentration need more computational effort in numerical simulations, the advantage of the presented approach in saving long computational times is evident. Another advantage of the ANNs approach is the ability to generalize a trained network to conductivity distributions different from those used in training. However, the accuracy of the approach in cases with higher conductivity variances is being investigated.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1434-3932
    Keywords: Schlüsselwörter  Intraoperative Doppler Sonographie ; Karotis-TEA ; Intraoperative Angiographie ; Keywords  Carotid TEA ; Doppler ultrasonography ; Intraoperative angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract   Large multicenter studies have recently provided long-term results substantiating the superiority of surgical as compared to conservative therapy for symptomatic and asymptomatic extracranial internal carotid stenoses of more than 70%. These results led to an increase in the frequency of thromboendarterectomies (TEA). However, indications are limited by the perioperative complication rate. This explains the need for a reliable method of immediate intraoperative quality control. The present prospective study investigates the value of microvascular Doppler sonography (MDS) in carotid TEA. Of 39 patients who underwent carotid TEA of symptomatic (n=19) or asymptomatic (n=20) carotid stenosis, more than 70% were submitted to both intraoperative angiography (IOA) and MDS. The sensitivity and specificity of the two techniques were compared in the light of the intraoperative findings. IOA has a higher sensitivity in demonstrating minimal sacciform pouch, which, however, is not therapeutically relevant. In other respects, both methods are of equal value. There were no therapeutically relevant false negative results by MDS. It appears to be advisable to apply MDS routinely in cases of carotid TEA. Intraoperative angiography should be performed in patients in whom changes detected by MDS require morphologic confirmation.
    Notes: Zusammenfassung   Große Multicenterstudien der letzten Jahre haben gezeigt, dass bei symptomatischen oder asymptomatischen Stenosen der extrakraniellen A. carotis interna von mehr als 70% die Langzeitergebnisse der operativen denen der konservativen Therapie überlegen sind. Diese Ergebnisse führten zu einer Zunahme der Karotisthrombendarteriektomien (Karotis-TEA). Da die Indikation zur chirurgischen Therapie maßgeblich durch die perioperative Komplikationsrate beeinflusst wird, ist die intraoperative Qualitätskontrolle ein obligater Bestandteil der Karotischirurgie. Diese Studie vergleicht die Wertigkeit der mikrovaskulären Dopplersonographie (MDS) als intraoperative Qualitätskontrolle bei der Karotis-TEA mit der der intraoperativen Angiographie. Bei 39 Patienten mit symptomatischer (n=19) und asymptomatischer (n=20) Karotisstenose von mehr als 70% wurde zur intraoperativen Qualitätskontrolle die MDS durchgeführt. Die Sensitivität, Spezifität und der positive Voraussagewert bei der Erkennung intraoperativer Gefäßveränderungen wurden mit den Ergebnissen der als ”golden standard” geltenden intraoperativen Angiographie verglichen. Die intraoperative Angiographie hatte eine höhere Sensitivität bei der Erkennung von therapeutisch irrelevanten minimalen sacciformen Ausbuchtungen der A. carotis interna. Der zeitliche Aufwand der intraoperativen Angiographie war wesentlich höher als der der MDS. Hinsichtlich therapeutisch relevanter Gefäßveränderungen lieferte die MDS keine falsch negativen Ergebnisse. Die MDS sollte bei jeder Karotis-TEA routinemäßig angewendet werden. Sie ist in der Lage, korrekturbedürftige Befunde zuverlässig zu erkennen. Die intraoperative Angiographie sollte durchgeführt werden, wenn durch die dopplersonographische Untersuchung Gefäßveränderungen festgestellt werden, die eine Ergänzung der funktionellen durch eine morphologische Untersuchung erfordern.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 471-472 (Dec. 2004), p. 87-91 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: During excessive fluid application processing, fluid ends up on the floor, the workers, and the machine, entail serious techno-environmental and biological problems. Very little fluid enters the tool/part interface. Recently, this excess fluid has become another costly control problem. Chemicals of all types introduced into the atmosphere must also be reduced to an absolute minimum. In this paper, the technique of minimum quantity of lubrication (MQL), which is the pulverization of a minimum volume of oil in a flow of compressed air, has been studied in face mill Ti-6Al-4V titanium alloys as one alternative to the use of abundant cooling to suppress the cutting heat resulted from low thermal conductivity and the density of the workpiece material. The results showed that MQL of 125ml/h flow amount was found to be the optimum, and there is no significant difference in temperature between MQL of this flow and wet cooling when low cutting speeds used
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Heat and mass transfer 36 (2000), S. 173-176 
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract  Using Green's function method, an analytical, closed form solution for the problem of transient mass diffusion into a two-layer medium is found. Two problems are considered; composite slab and composite cylinder. Carbon diffusion into slab composed of Ferrite steel and Austenite steel in perfect contact is investigated. From the results, the time required for carbon concentration to reach a certain level is estimated.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 61 (2000), S. 119-125 
    ISSN: 1572-8943
    Keywords: alkyl/arylphosphine gold(I) cyanide ; redox reaction ; thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Combined TG/DTA techniques have been used to study the thermal decomposition of R3PAuCN (where Ris ethyl, cyclohexyl, o-tolyl, m-tolyl, p-tolyl, allyl, cyanoethyl,1-naphthyl and phenyl) complexes. It was observed that all of these complexes underwant decomposition cum redox reactions in the range of 200–600oC with evolution of both transligands, which are phosphine and cyanide, leaving metallic gold as a residue. The thermal decomposition of o-Tol3PAuCN has revealed that this is a stepwise process. In the first step decomposition takes place with evolution of phosphine and generation of AuCN, which in second step undergoes a redox reaction to produce metallic gold. The DTA curves have also confirmed these results.
    Type of Medium: Electronic Resource
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