bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conformation‐activity relationships of cyclo‐constrained µ/δ opioid agonists derived from the N‐terminal tetrapeptide segment of dermorphin/deltorphin
Authors: Rodziewicz‐MotowidŁo Sylwia , Czaplewski Cezary , Łuczak Sylwia , Ciarkowski Jerzy 
Published: March 2008

AbstractThe N‐terminal tetrapeptide segments of dermorphin (Tyr–D‐Ala–Phe–Gly–Tyr–Pro–Ser–NH2) and deltorphin (Tyr–D‐Ala–Phe–Asp/Glu–Val–Val–Gly–NH2) are agonists at the opioid receptors µ and δ, respectively. [D‐Arg2, Lys4]‐dermorphin‐(1–4) amide (Tyr–D‐Arg–Phe–Lys–NH2, DALDA) and [Dmt1]DALDA (where Dmt is 2′,6′‐dimethyltyrosine) are among the most potent and selective µ‐agonists reported to date, both in vitro (having picomolar µ receptor affinity) and in vivo. In this communication, conformation‐activity studies of the following four cyclic analogs of DALDA are presented and discussed: the lead peptide S2,S4‐cyclo (Tyr–D‐Cys–Phe–Cys–NH2), constrained by means of an S4.2S4.4 disulfide between Cys2 and Cys4; its two cis and trans C4.2C4.4‐olefinic dicarba analogs, and the product of saturation of them both. They are potent nonselective or moderately µ‐selective opioid agonists in vitro.They have been synthesized and tested earlier [Berezowska I, Chung NN, Lemieux C, Wilkes BC, and Schiller PW, Acta Biochim Polon 53, 2006, 73–76]. We have studied their conformations using NMR and molecular dynamics. With major conformational constraints imposed by the 11‐membered ring spanning residues 2–4, they show well defined conformations of this ring, while the exocylic Tyr1 and Phe3 side chains still have significant conformational freedom. The more active and selective µ versus δ disulfide and saturated dicarba agonists seem to have in common: (i) their ring structures more flexilble than those of the other two and (ii) their ring structures similar to each other and more diverse than those in the other two. Given this and the small size of the peptides having confirmed bioactivity profiles, there is a chance that their conformations determined in solution approach receptor‐bound conformations. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Surface modification of Ti by an Ar‐O mixture dc plasma
Authors: Valencia R. A. , de la Piedad‐Beneitez A. , de la Rosa‐Vázquez J. , López‐Callejas R. , Barocio S. R. , Mercado‐Cabrera A. , Peña‐Eguiluz R. , Muñoz‐Castro A. E. 
Published: March 2008

AbstractTitanium surface oxidation deserves a growing interest in biomedical engineering due to its biocompatibility enhancement and mechanical performance. In this work we report on the Ti surface modification, conducted into a toroidal vacuum vessel, by a DC plasma formed by an oxygen‐argon (20/80) mixture. By varying the gas pressure within the 2.5 to 5×10–3 mbar interval at the sample bias voltage –3000 V, we have gained control over the sample temperature up to the order of 650°C. In turn, the composition of the modified surface has been controlled by adjusting the flow rates of the gas mixture and the above mentioned temperature. The samples were characterised by microhardness tests, SEM, XRD and Raman spectroscopy. The diagnostics revealed a rutile TiO2 and TiO1.04 phase content in the modified layer. The remarkable effects of Ti sample temperature and treatment time on the morphology of the surface structure were explored. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monitoring of electric potential of semiconductor wafer
Authors: Noras Maciej A. , Maryniak William A. 
Published: March 2008

AbstractThe International Technology Roadmap for Semiconductors (ITRS) forecasts increasing number of issues with electrostatic discharge (ESD) related phenomena and the need for improved wafer electrostatic charge control in semiconductor wafer processing. This means that wafer metrology should encompass charge measurements as a routine operation. The ability to make wafer potential measurements in‐line, either before and after the wafer processing can help with detection and prevention of the ESD events and with minimizing wafer charging issues during loading/unloading operations. One of the instruments utilized in such measurements is an electrostatic voltmeter (ESVM). In this paper the authors would like to introduce and discuss novel designs of the ESVMs. A new, non‐contacting probe allows for the measurement of surface voltages with DC stability and millivolt sensitivity. Another design features a specially designed probe that permits contact with the wafer surface without transfer of the electric charge to/from the surface under test. Results of performance evaluation along with feasibility studies of the sensors are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deuterium retention near surface of TiO2 by low‐voltage D2 plasma discharge
Authors: Matsunami N. , Tanaka T. , Ohno N. , Tokitani M. 
Published: March 2008

AbstractWe have investigated deuterium (D) uptake in TiO2 (rutile) films under exposure of low‐energy D2+ ions and thermal release of D from TiO2 films. The amount of deuterium in the films was analysed by means of nuclear reaction analysis, D(3He, α)p. D‐uptake under AC‐glow discharge in D2 pressure of ∼90 Pa is compared with that under DC‐discharge with well‐defined energy of D2+ ions in D2 pressure of ∼0.1 Pa. The results imply that the effective energy of D2+ ions in AC‐glow discharge is much lower than the energy derived from the applied voltage. The results are also compared with those for Ti sheet exposed to low‐energy D2+ ions. We find that D‐release temperature from TiO2 is considerably lower than from Ti, though D‐uptake in TiO2 is smaller than in Ti. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Background‐error correlation length‐scale estimates and their sampling statistics
Authors: Pannekoucke O. , Berre L. , Desroziers G. 
Published: March 2008

AbstractThis article presents different formulae to estimate correlation length‐scales, and an evaluation of their qualities for practical diagnostic applications. In particular, two new and simple formulae are introduced, which only require the computation of correlation with a single point for a given direction. It is then shown in a 1D heterogeneous context that all formulations lead to similar realistic length‐scale values, and that they represent geographical variations rather well.The estimation of length‐scales within a finite ensemble is also studied. While a positive bias occurs when the ensemble size is too small, the standard deviation of the length‐scale estimation is shown to be the main influence on the estimation error. The spatial structure of sampling noise is then diagnosed, and effects of spatial filtering techniques on the bias and standard deviation are illustrated.Finally, an ensemble of perturbed forecasts from a global NWP model is used, showing a real application example. Copyright © 2008 Royal Meteorological Society
Maintenance contract assessment for aging systems
Authors: Lisnianski Anatoly , Frenkel Ilia , Khvatskin Lev , Ding Yi 
Published: March 2008

AbstractThis paper considers an aging system, where the system failure rate is known to be an increasing function. After any failure, maintenance is performed by an external repair team. Repair rate and cost of repair are determined by a corresponding maintenance contract with a repair team. There are many different maintenance contracts suggested by the service market to the system owner. In order to choose the best maintenance contract, a total expected cost during a specified time horizon should be evaluated for an aging system. In this paper, a method is suggested based on a piecewise constant approximation for the increasing failure rate function. Two different approximations are used. For both types of approximations, the general approach for building the Markov reward model is suggested in order to assess lower and upper bounds of the total expected cost. Failure and repair rates define the transition matrix of the corresponding Markov process. Operation cost, repair cost and penalty cost for system failures are taken into account by the corresponding reward matrix definition. A numerical example is presented in order to illustrate the approach. Copyright © 2008 John Wiley & Sons, Ltd.
Surface characterization of polyester resins formulated with different cross‐linking agents
Authors: Marino Paolo , Lowe Chris , Abel Marie‐Laure , Watts John F. 
Published: March 2008

AbstractThree thermally cured coatings, formulated on a low Tg isophthalic‐based polyester, were investigated by XPS and ToF‐SIMS. A model formulation was employed for all three coatings investigated; however, the cross‐linking agents used were varied for each formulation. Hexamethoxymethyl melamine (HMMM), tris‐isocyanurate (TIC), and a combination of HMMM and TIC were included as the cross‐linking agents. The use of TIC alone required a tin‐based catalyst to promote the curing reaction.The aim of this work was to investigate the difference in the surface compositions of the three coatings and the distribution of the different cross‐linking agents used. This was in preparation for further studies which will involve interfacial analysis in order to elucidate the mechanism responsible for intercoat adhesion.The XPS analysis of the coating surfaces revealed a nitrogen concentration consistent with the concentration expected from the formulation for the coating containing HMMM. In the other two formulations a lower concentration than calculated was observed. The surface concentration of the two cross‐linking agents was not influenced by the presence of the others; indeed, the formulation containing both cross‐linking agents was, in terms of nitrogen concentration, merely a simple combination of the other two coatings. Peaks diagnostic of the cross‐linking agents were observed in ToF‐SIMS spectra acquired from the coating surfaces. By using XPS and ToF‐SIMS analysis, we could determine that the HMMM and the TIC have a different distribution at the coating surface, that is not affected by the presence of the other. Copyright © 2008 John Wiley & Sons, Ltd.
Insight into the Enzymatic Degumming Process of Soybean Oil
Authors: Yang Bo , Zhou Rong , Yang Ji‐Guo , Wang Yong‐Hua , Wang Wei‐Fei 
Published: March 2008

AbstractAn enzymatic degumming trial of soybean oil was carried out at a capacity of 400 tons/day by applying microbial phospholipase A1 from Thermomyces lanuginosus/Fusarium oxysporum. When the pH was kept in the range of 4.8–5.1, less than 10 mg/kg of phosphorous content of The oil was obtained. The gum and oil were easily separated after centrifugation and the oil loss was minimal under the process conditions. Through analysis of phospholipids compounds in the gum by Electrospray Ionization‐Mass Spectrometer and phosphorous content, it could be seen that both glycerophospholipids and lysophospholipids existed with contents of 45.7 and 54.3%, respectively. The performance of enzymatic degumming was found to be related to the production of glycerophospholipids.
Synthesis of Ethyl 5Z,9Z,12Z‐octadecatrienoate (ethyl pinolenate) and Methyl 12Z,15Z‐octadecadienoate
Authors: Kaltia Seppo , Matikainen Jorma , Ala‐Peijari Maija , Hase Tapio 
Published: March 2008

AbstractPinolenic acid (5Z,9Z,12Z‐octadecatrienoic acid, 1a), one of the most abundant trienoic fatty acids in nature, is very difficult to obtain in quantity in a pure state from the highly complex mixture of unsaturated tall oil fatty acids. For this reason its chemistry has been little studied when compared to linolenic or linoleic acids. A simple synthesis of esters of 1a and of 12Z,15Z‐octadecadienoic acid 3 using the one pot double Wittig procedure is described here. The products of double Wittig reactions were purified by argentation chromatography, and their structural purity was established by 1H‐, 13C‐NMR and 2D‐NMR spectroscopies.
Rifampin and digoxin induction of MDR1 expression and function in human intestinal (T84) epithelial cells
Authors: Haslam I S , Jones K , Coleman T , Simmons N L 
Published: March 2008

Background and purpose: Oral drug bioavailability is limited by intestinal expression of P‐glycoprotein (MDR1, Pgp, ABCB1) whose capacity is regulated via nuclear receptors e.g. the pregnane X receptor (PXR, SXR, NR1I2). In order to study dynamic regulation of MDR1 transport capacity we have identified the T84 epithelial cell‐line as a model for human intestine co‐expressing MDR1 with PXR. The ability of rifampin, a known PXR agonist and digoxin, a model MDR1 substrate, to regulate MDR1 expression and transport activity has been tested, in these T84 cells.Experimental approach: Transport was assayed by bi‐directional [3H]‐digoxin transepithelial fluxes across epithelial layers of T84 cells seeded onto permeable filter supports following pre‐exposure to rifampin and digoxin. Quantitative real‐time PCR, Western blotting and immunocytochemistry were used to correlate induction of MDR1 transcript and protein levels with transport activity.Key results: Rifampin exposure (10 μM, 72 hours) increased MDR1 transcript levels (3.4 fold), MDR1 total protein levels (4.4 fold), apical MDR1 protein (2.7 fold) and functional activity of MDR1 (1.2 fold). Pre‐incubation with digoxin (1 μM, 72 hours) potently induced MDR1 transcript levels (92 fold), total protein (7 fold), apical MDR1 protein (4.7 fold) and functional activity (1.75 fold). Whereas PXR expression was increased by rifampin incubation (2 fold), digoxin reduced PXR expression (0.3 fold).Conclusions and implications: Chronic digoxin pre‐treatment markedly upregulates MDR1 expression and secretory capacity of T84 epithelia. Digoxin‐induced changes in MDR1 levels are distinct from PXR‐mediated changes resulting from rifampin exposure.
The Behaviour of Infused Human Platelets During the First Twenty‐Four Hours After Infusion
Authors: Davey M. G. , Lander H. 
Published: March 2008

When freshly collected human platelets are transfused into normal recipients, an appreciable proportion disappears extremely rapidly from the circulation and does not reappear. This proportion increases with the number of manipulations performed in the preparation of the platelet concentrate (Gardner, Howell and Hirsch, 1954), and with the period of storage before infusion (Baldini, Costea and Dameshek, 1960). Those platelets which remain in the circulation after 24 hours—so‐called ‘viable’platelets—disappear slowly from the blood in the course of a further 7–10 days (see reviews by Najean and Bernard, 1960, and Odell and Kniseley, 1962). This period of platelet survival in the circulation is similar to that determined by labelling platelets in vivo with di‐isopropylfluorophosphonate‐32 P (DF32 P) (Leeksma and Cohen, 1956; Zucker, Ley and Mayer, 1961).Following the infusion of labelled platelets into normal recipients, it has also been shown that the platelet‐bound radioactivity in the blood increases after 30 minutes to reach a maximum within 24–48 hours of infusion (Adelson, Rheingold and Crosby, 1957; Reisner, Keating, Friesen and Loeffler, 1958; Aas and Gardner, 1958; and others). This is contrary to what might be anticipated. A delayed increase in the number of circulating platelets has also been shown to occur when unlabelled platelets are given to thrombocytopenic subjects (Aas and Gardner, 1958). No such change is observed, however, when DF32P is injected to label circulating platelets (Zucker et al., 1961); this suggests that the phenomenon is due to changes which occur during the removal of platelets from the body and/or their manipulation in vitro.The fate of those infused platelets which are immediately and irreversibly cleared from the circulation is unknown; nor is it known where the potentially viable platelets reside before their return to the circulation, nor where they are finally destroyed. Surface‐counting procedures using platelets labelled in vitro with 51Cr have led some workers to suggest that temporary accumulation occurs in the liver, the lungs and possibly the spleen, and that the liver and spleen play some role in their final destruction (Aas and Gardner, 1958; Najean and Bernard, 1960; Najean, Larrieu and Bernard, 1961). This study is concerned particularly with the sequence of events in the brief period immediately following the infusion of 51Cr‐labelled human platelets—a period in which some of them disappear rapidly from the circulation, and later return to it. We have carried out 36 studies of these events.
Studies on Fibrinogen Fractions Isolated from Human Plasma by Precipitation with Cold Ether
Authors: Mackay Margaret , Maycock W. d'A. , Silk Elsie , Combridge B. S. 
Published: March 2008

During clinical trials of a human antihaemophilic globulin concentrate (HAHG) prepared from very fresh plasma by the method of Kekwick and Wolf (1957), it was observed (Maycock, Evans, Vallet, Combridge, Wolf, MacGibbon, French, Wallett, Dacie, Biggs, Handley and Macfarlane, 1963) that the transfusion of this material into haemophiliacs was sometimes followed by reactions similar to those observed by Fox, Goldsmith, Kidd and Lewis (1961) after the intravenous injection of purified bradykinin. A chemically similar fraction (ETF), prepared from aged plasma, has been used for many years for the treatment of hypofibrino‐genaemia without any reported reactions.The reactions described by Maycock et al. (1963) were sufficiently frequent and severe to warrant an investigation of the kininogenic properties of HAHG and, for comparative purposes, of ETF. For reasons not understood, but clearly associated with the adoption of a modification of the original technique (Kekwick and Walton, 1965), reactions occurring during the transfusion of recently prepared batches of HAHG into haemophiliacs are now no greater in number and severity than those occurring during the transfusion of fresh plasma. Human plasma contains prokininogenases, the precursors of enzymes which hydrolyse protein substrates (kininogens, kallidinogens) to produce kinins, polypeptides which cause vasodilation and plain muscle constriction (Lewis, 1960). Activation of two of these proenzymes, kallikrein and plasminogen (profibrinolysin), could lead to the production of kinin in HAHG either during preparation, or during transfusion, and might cause the observed reactions.
The Anaemia of Erythropoietic Porphyria with the First Description of the Disease in an Elderly Patient
Authors: Kramer S. , Viljoen E. , Meyer A. M. , Metz J. 
Published: March 2008

less than 60 cases of erythropoietic porphyria have been described since the original report by Shultz in 1874. It is a congenital disease and is generally thought to be transmitted in a non sex‐linked recessive mode (Goldberg and Rimington, 1962, p. 49; Heilmeyer, Clotten, Kerp, Merker, Parra and Wetzel, 1964). All cases in whom a definitive statement was made regarding age of onset presented in childhood and no patient has survived to middle age (Goldberg and Rimington, 1962, p. 55). The first of the two cases described here is unusual in that the disease only manifested itself after the age of 50Most patients with erythropoietic porphyria have a haemolytic anaemia (Goldberg and Rimington, 1962, p. 54). There is frequently a reticulocytosis and the serum bilirubin may be slightly raised. Urobilinogen and stercobilinogen excretion are increased. Erythrocyte survival has been studied in a few cases with equivocal results (London, West, Shemin and Rittenburg, 1950; Gray, Muir and Neuberger, 1950; Rosenthal, Lipton and Asrow, 1955; Canivet and Pernard‐Considére, 1958; Heilmeyer et al., 1964). In an attempt to elucidate the mechanism underlying the anaemia associated with this disease two cases of erythropoietic porphyria were studied using a combined radioactive iron and chromium technique to make detailed simultaneous measurements of red‐cell production and destruction.
Electron‐Microscope Studies of the Red Cell in Paroxysmal Nocturnal Haemoglobinuria
Authors: Lewis S. M. , Danon D. , Marikovsky Y. 
Published: March 2008

It is generally accepted that in paroxysmal nocturnal haemoglobinuria (PNH) there is a fundamental defect in the red cell, but the nature of the defect has not been completely elucidated. The red cells show no particular abnormal morphological features when viewed by the optical microscope but several studies have been carried out on the red‐cell membrane to see if any defect might be revealed by electron microscopy. Matthes, Schubothe and Lindemann (1951) noted an abnormality in the red cell membrane consisting of a patchy appearance with many clefts. This was subsequently confirmed by Braunsteiner, Gisinger and Pakesch (1956) and by Cecchi and Conestabile (1957). However, results have been variable, possible due to the fact that the usual method of preparing red‐cell membranes (‘ghosts’) by drastic osmotic haemolysis in distilled water results in tears and other damage to the membrane (Ponder and Ponder, 1960, 1961; Danon, 1961). Thus, for example, when Douglas and Eaton (1955) used a slight variation of the usual technique they concluded that the membranes of PNH cells were not abnormal, although it should be remarked that electron‐dense ovoid structures can be seen in the illustration of their shadow‐cast preparation.In order to avoid subjecting red cells to a very low ionic strength, Danon, Nevo and Marikovsky (1956) devised a method of dialysis of red‐cell suspensions against hypotonic NaCl, by means of which a gradual decrease in the salt concentration of the medium surrounding the red cells is achieved. By this method ghosts of red cells have been obtained practically free of haemoglobin and relatively undamaged. Electron microscope studies of PNH cells prepared by this method showed a number of abnormalities, which will be described in this paper. It was observed that many of the PNH cell membranes contained electron‐dense material of varying form, size and amount. In order to investigate the nature of this residual material electron microscopy of ultra‐thin sections of the red cells was also carried out.
Changes in Iron Mobilization and Utilization Induced by Acute Haemorrhage
Authors: Meital V. , Izak G. , Rachmilewitz M. 
Published: March 2008

The measurement of the rate of appearance in the circulating blood of radioactive iron that has been previously injected is one of the most convenient techniques in the study of red‐cell production. Using this isotope, Dubach, Moore and Minnich (1946), Dubach, Callender and Moore (1948), Saylor and Finch (1953) and Dubach, Moore and Callender (1955) reported observations on the mechanism of the absorption of iron and its deposition in the storage organs. Jandl, Inman, Simmons and Allen (1959) and Morgan and Laurell (1963) described the competition between the reticulocytes and the iron‐binding protein of plasma for iron. Lamerton, Belcher and Harris (1959), Stohlman (1959), Donohue, Gabrio and Finch (1958), Bothwell, Pribilla, Mebust and Finch (1958) and others examined the uptake of iron by the early erythroid precursors in human and animal bone marrow. Stohlman (1959), Alpen and Cranmore (1959) and others examined the relationship between the incorporation of 59Fe into erythroid precursors and the release of mature red cells into the circulation. Information concerning iron absorption, utilization, storage and mobilization in iron‐deficiency anaemia due to chronic blood loss is also abundant.The present paper deals with the erythropoietic response as measured by ferrokinetic studies in the rat following acute haemorrhage. Evidence will be presented to show that this response is different from that produced by erythropoietin administration to the rat.