1,986 research outputs found
Structural Geology of the Cariboo Gold Mining District, East-Central British Columbia:
No full textL.C. Struik.Memoir (Geological Survey of Canada) ; 421
Depolarization and decreased surface expression of K+ channels contribute to NSAID-inhibition of intestinal restitution
No full textNon-steroidal anti-inflammatory drugs (NSAIDs) contribute to gastrointestinal ulcer formation by inhibiting epithelial cell migration and mucosal restitution; however, the drug-affected signaling pathways are poorly defined. We investigated whether NSAID inhibition of intestinal epithelial migration is associated with depletion of intracellular polyamines, depolarization of membrane potential (Em) and altered surface expression of K+ channels. Epithelial cell migration in response to the wounding of confluent IEC-6 and IEC-Cdx2 monolayers was reduced by indomethacin (100μM), phenylbutazone (100μM) and NS-398 (100μM) but not by SC-560 (1μM). NSAID-inhibition of intestinal cell migration was not associated with depletion of intracellular polyamines. Treatment of IEC-6 and IEC-Cdx2 cells with indomethacin, phenylbutazone and NS-398 induced significant depolarization of Em, whereas treatment with SC-560 had no effect on Em. The Em of IEC-Cdx2 cells was: −38.5±1.8mV under control conditions; −35.9±1.6mV after treatment with SC-560; −18.8±1.2mV after treatment with indomethacin; and −23.7±1.4mV after treatment with NS-398. Whereas SC-560 had no significant effects on the total cellular expression of Kv1.4 channel protein, indomethacin and NS-398 decreased not only the total cellular expression of Kv1.4, but also the cell surface expression of both Kv1.4 and Kv1.6 channel subunits in IEC-Cdx2. Both Kv1.4 and Kv1.6 channel proteins were immunoprecipitated by Kv1.4 antibody from IEC-Cdx2 lysates, indicating that these subunits co-assemble to form heteromeric Kv channels. These results suggest that NSAID inhibition of epithelial cell migration is independent of polyamine-depletion, and is associated with depolarization of Em and decreased surface expression of heteromeric Kv1 channels.ID: S0006295207001931; M3: Article; Accession Number: S0006295207001931; Author: L.C. Freeman (b); Author: D.F. Narvaez (a); Author: A. McCoy (a); Author: F.B. von Stein (c); Author: S. Young (b); Author: K. Silver (a); Author: S. Ganta (b); Author: D. Koch (b); Author: R. Hunter (b); Author: R.F. Gilmour (c); Author: J.D. Lillich (a, ⁎); Affiliation: Department of Clinical Sciences, Kansas State University, Manhattan, KS 66506, United States; Affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States; Affiliation: Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, United States; Keyword: Non-steroidal anti-inflammatory drugs; Keyword: Intestinal epithelial cells; Keyword: Membrane potential; Keyword: Potassium channels; Number of Pages: 12; Language: English;Source type: Electronic(1)http://search.ebscohost.com/login.aspx?direct=true&db=edselp&AN=S0006295207001931&site=eds-live&scope=sit
Studies of the oxidation of zinc dialkyldithiophosphates and related compounds
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Raman spectroscopic analysis of Zn[(R0)2 PS2]2 (ZDDP) and Pb[(RO)2 PS2]2 (R=ethyl or n-butyl) indicate that four sulphur atoms co-ordinate to each zinc atom whilst only two co-ordinate to each lead atom. Dialkyl dithiophosphoric arids (RO)2P(:S)SH exhibit rotational isomerism about P-S and P-0 bonds. Temperature-dependence studies of 1 r (SH) and -(P-S) band intensities indicate LH for the equilibria to be 2.5 kJ mol-1,R= iso-propyl ; 3 kJmol-1 nice, R=n-butyl; 4.5 kJ mol-1, R= n-octyl. Thin film high pressure EEC analysis of solutions containing ZDDP's or related compounds reveal the following trend with respect to antioxidant effectiveness (R = n-octyl , R’ = iso-octyl):
(RO)2 P(:S)SH < [(RO2) PS2]2 < Zn [(RO)2 PS2]2 < commercial Zn[(R’O)2 PS2]2
Successive twofold dilutions of 0.08 M organothiophosphate antioxidant in squalane reduce the observed oxidation onset teTeratures and increase the heats of reaction these tend towards values determined for pure squalane. Dynamic DSC studies of cumene hydroperoxide (CHP) reduction (0.063 IA) by n-butyl ZDDP and notable related compounds (0.C41, ) in squalane produce the following trend of reactivity with respect to the decomposition of CHP (R.= n-butyl)
Zn[(RO)2 PS2]2 > [ (RO)2 PS2]2 > RSH > R2S2 > (RS)3 > R2S > (RO)2 (RS)P=S.
Detailed investigations by dynamic and isothermal DSC on the reduction of CHP by
[ R0)2 PS2]2 (R= n-octyl , n-butyl ) indicate that the mechanism of hydroperoxide decomposition is autocatalytic. The half-lives determined by F=31 NMR spectroscopic investigations on the oxidation of Zn[(RO)2 PS2 ]2 (R= n-octyl) to [(RO)2 PS2]2 and ClZn4[(RO)2 PS2 ]6 (basic ZDDP) by excess CHP (0.12 m ) are i) in squalane 10 min ; ii) in cyclohonane 7 min ; iii) in nitrobenzene 46 min. In cyclohexane and squalane the remaining hydroperoxide oxidises n-octyl basic ZDDP to an uncharacterised basic salt that produces a P-31 NMR signal 0.2 ppm lower than n-octyl basic MEP, and [(RO)2 PS2]2. The basic ZDDP salts are more resistant to oxidation by CHP than ZDDP and major products from their oxidation include [(R0)2 PS2]2, an unidentified dithiophosphate (with a P-31 RC signal of 84.4 ppm w.r.t tributyl phosphate) and an unidentified monothiophosphate (49 ppm).Supported by the Ministry of Defence D.Q.A/TS Woolwich
Les Observations sur l'éloquence de l'abbé de Saint-Pierre
No full textAbbé de Saint-Pierre : Observations sur l'éloquence. Presented by Lawrence Kerslake.
Many of the abbé de Saint-Pierre's writings remain little-known or even unpublished. The Observations sur l'éloquence constitute his chief discussion of literature. A preliminary draft appeared in the Mercure in 1726, but the work subsequently underwent two major revisions, both states represented in Ms. R.248 of the Bibliothèque publique et universitaire in Neuchâtel. A further copy (BNF. N.a.fr. 11232), with a few additional changes, is published here. The ideas in the text show the author to be a 'Modern' in his position on beauty and literary effect, and reflect his life-long concern for the improvement of his fellow-citizens.Kerslake L.C. Les Observations sur l'éloquence de l'abbé de Saint-Pierre. In: Dix-huitième Siècle, n°31, 1999. Mouvement des sciences et esthétique(s) sous la direction de Christine Rolland, François Azouvi et Michel Baridon. pp. 305-328
A 0.53pJK<sup>2</sup> 7000μm<sup>2</sup> resistor-based temperature sensor with an inaccuracy of ±0.35°C (3σ) in 65nm CMOS
No full textIn microprocessors and DRAMs, on-chip temperature sensors are essential components, ensuring reliability by monitoring thermal gradients and hot spots. Such sensors must be as small as possible, since multiple sensors are required for dense thermal monitoring. However, conventional BJT-based temperature sensors are not compatible with the sub-1V supply of advanced processes. Subthreshold MOSFETs can operate from lower supplies, but at high temperatures their performance is limited by leakage [1,2]. Thermal diffusivity (TD) sensors achieve sub-1V operation and small area with moderate accuracy, but require milliwatts of power [3]. Recently, resistor-based sensors based on RC WienBridge (WB) filters have realized high resolution and energy efficiency [4,5]. Fundamentally, they are robust to process and supply-voltage scaling. However, their readout circuitry has been based on continuous-time (CT) ΔΣ ADCs or frequency-locked loops (FLLs), which require precision analog circuits and occupy considerable area (>0.7mm 2 ).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microelectronic
A ±4A high-side current sensor with 25V input CM range and 0.9% gain error from -40°C to 85°C using an analog temperature compensation technique
No full textThis paper presents a fully integrated ±4A current sensor that supports a 25V input common-mode voltage range (CMVR) while operating from a single 1.5V supply. It consists of an on-chip metal shunt, a beyond-the-rails ADC [1] and a temperature-dependent voltage reference. The beyond-the-rails ADC facilitates high-side current sensing without the need for external resistive dividers or level shifters, thus reducing power consumption and system complexity. To compensate for the shunt's temperature dependence, the ADC employs a proportional-to-absolute-temperature (PTAT) reference voltage. Compared to digital temperature compensation schemes [2,3], this analog scheme eliminates the need for a temperature sensor, a band-gap voltage reference and calibration logic. As a result, the current sensor draws only 10.9μA and is 10x more energy efficient than [2]. Over a ±4A range, and after a one-point trim, the sensor exhibits a 0.9% (max) gain error from -40°C to 85°C and a 0.05% gain error at room temperature. The former is comparable with that of other fully-integrated current sensors [2-4], while the latter represents the state-of-the-art.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Optimised control and pipe burst detection by water demand forecasting
No full textWater demand forecasting The total water demand in an area is the sum of the water demands of all individual domestic and industrial consumers in that area. These consumers behave in repetitive daily, weekly and annual patterns, and the same repetitive patterns can be observed in the drinking water demand. The observations of the water demand were used to develop a fully adaptive forecasting model for short-term drinking water demand. The forecasting model automatically stores and updates water demand patterns and demand factors, and uses these when forecasting the water demand for the next 48 hours with 15-min. time steps (192 values). The model uses as single input the measured water demand and calendar information that appoints deviant days. The model is easy to implement, fully adaptive and accurate, which makes it suitable for application in real time control and pipe burst detection. The model was tested on datasets containing six years of water demand data in six different areas in the central and southern part of Netherlands. The areas vary in size from very large (950,000 inhabitants) to small (2,400 inhabitants). The mean absolute percentage error (MAPE) for the 24-hours forecasts varied between 1.44-5.12%, and for the 15-min. time step forecasts between 3.35-10.44%. When using temperature information as extra input, the average forecasting errors could be reduced by 6.3%, and the largest forecasting errors by 9.4%. ? Optimised control A first application of a short-term water demand forecasting model is using it for optimised control of water supply systems. The conventional automatic control of the production flow or the clear water pumps is often quite simple, resulting is highly varying production or transportation flows. This basic control results in sub-optimal operation of the system, and the operation can be improved when forecasts of the water demands in the system are used. To assess the differences between conventional basic control and optimised predictive control, five existing water supply systems in the Netherlands and one system in Poland were examined. The operational results in a period with conventional control were compared to the results in a period with optimised control. The results showed that the variation in the production flow was 75% lower with optimised control, which resulted in 17% lower turbidity rates in the clear water. The optimised control also resulted in a reduction of the energy costs of 5.2% at the Dutch systems and 11.5% at the Polish system. Pipe burst detection A second application of a short-term water demand forecasting model is using it for pipe burst detection. The now-cast of the water demand a good estimator for the actual water demand under normal circumstances. By comparing the measured water demand to this forecasted water demand, anomalies like pipe bursts can be detected. A pipe burst detection method based on this principle was developed. In the method, all measured and forecasted signals are transformed to moving averaged values over time frames of 2 up to 240 minutes. The transformation to longer moving average time frames resulted in lower threshold values which enabled the detection of smaller pipe bursts. The threshold values that distinguish between normal forecasting inaccuracies and pipe bursts, are derived by evaluating the forecasting deviations in the year prior to the monitoring year. The method was tested on different historic datasets with hydraulic data and pipe burst information in three areas in the western part of the Netherlands, and six areas in the northern part of the Netherlands. The method proved to be effective for detecting the relatively larger bursts: 80-90% of the bursts could be detected within 20 minutes, while generating false alarms on 3% of the days without a burst. The size of the pipe burst that can be detected showed a strong relation with the size of the area. Based on an analysis of problematic bursts, it was found that the burst detection method can effectively be applied to areas with an average demand of 150 m3/h or less.Water ManagementCivil Engineering and Geoscience
A phase-domain readout circuit for a CMOS-compatible thermal-conductivity-based carbon dioxide sensor
No full textThe measurement of carbon-dioxide (CO2) concentration is very important in home and building automation, e.g. to control ventilation in energy-efficient buildings. This application requires compact, low-cost sensors that can measure CO2 concentration with a resolution of <200 ppm over a 2500ppm range. Conventional optical (NDIR-based) CO2 sensors require components that are CMOS-incompatible, difficult to miniaturize and power-hungry [1]. Due to their CMOS compatibility, thermal-conductivity-based sensors are an attractive alternative [2,3]. They exploit the fact that the thermal conductivity (TC) of CO2 is lower than that of the other constituents of air, so that CO2 concentration can be indirectly measured via the heat loss of a hot wire to ambient. However, this approach requires the detection of very small changes in TC (0.25 ppm per ppm CO2 [3]).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Author Correction: Imaging-based representation and stratification of intra-tumor heterogeneity via tree-edit distance
No full textMartina Sollini and Paola Anna Erba were omitted from the author list in the original version of this Article. The Author Contributions section now reads: “L.C. conceived the pipeline, set up the case study, analysed the results, prepared the figures, and wrote the manuscript. M.P. formulated and tuned the pruned tree edit distance, provided the mathematical proofs and the simulation study, and wrote the manuscript. A.R. contributed to implement the patient representation pipeline. M.S. segmented the Prostate Cancer lesions and extracted the radiomic features for all patients in the case study. P.A.E collected the data and enrolled the patients in the clinical study. F.I. supervised the analyses and the conception of the pipeline. L.C., M.P., A.R. and F.I. reviewed and approved the manuscript.” The original Article and accompanying Supplementary Information file have been corrected.</p
Integration of drinking water treatment plant process models and emulated process automation software
No full textThe objective of this research is to limit the risks of fully automated operation of drinking water treatment plants and to improve their operation by using an integrated system of process models and emulated process automation software. This thesis contains the design of such an integrated system. The use of the system is investigated in the three identified applications, i) optimization of process control, ii) training of operation supervisors and iii) virtual commissioning of process automation software.Water ManagementCivil Engineering and Geoscience
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