bluuebunny/crossref_metadata_2025 huggingface dataset:
Xenopus Zic4: Conservation and diversification of expression profiles and protein function among the Xenopus Zic family
Authors: Fujimi Takahiko J. , Mikoshiba Katsuhiko , Aruga Jun
Published: July 2006

We compared the expression and function of Xenopus Zic4 with those of the other four Xenopus laevis Zic family members (Zic1, Zic2, Zic3, and Zic5). Zic4 expression was detected mainly in the neural plate border, dorsal neural tube, and somites, and was similar to that of Zic1, which is adjacent to Zic4 on the same chromosome. Injection of wild‐type or mutant Zic4 RNA caused the induction of neural crest marker gene expression, hyperplastic neural tissue, and ectopic pigment cell formation, indicating that Zic4 can induce neural and neural crest tissue, as can other Xenopus Zic genes. Deletion analysis showed that the zinc‐finger domain is critical for many Zic4 functions, but the C‐terminal region is differently involved in induction of two neural crest markers, Slug and Sox10. The protein function as determined by the animal cap explant assay was similar to that of Zic5, but different from those of Zic1, Zic2, and Zic3, suggesting that Xenopus Zic genes can be divided into two groups based on function. These results indicate that the five Xenopus Zic genes cooperatively regulate both neural and neural crest development, despite significantly diverged expression profiles and functions. Developmental Dynamics 235:3379–3386, 2006. © 2006 Wiley‐Liss, Inc.
Influence of genotypes and precore mutations on fulminant or chronic outcome of acute hepatitis B virus infection
Authors: Ozasa Atsushi , Tanaka Yasuhito , Orito Etsuro , Sugiyama Masaya , Kang Jong-Hon , Hige Shuhei , Kuramitsu Tomoyuki , Suzuki Kazuyuki , Tanaka Eiji , Okada Shunichi , Tokita Hajime , Asahina Yasuhiro , Inoue Kazuaki , Kakumu Shinichi , Okanoue Takeshi , Murawaki Yoshikazu , Hino Keisuke , Onji Morikazu , Yatsuhashi Hiroshi , Sakugawa Hiroshi , Miyakawa Yuzo , Ueda Ryuzo , Mizokami Masashi
Published: July 2006

The outcome of acute hepatitis B virus (HBV) infection is variable, influenced by host and viral factors. From 1982 through 2004, 301 patients with acute HBV infection entered a multi-center cross-sectional study in Japan. Patients with fulminant hepatitis (n = 40) were older (44.7 ± 16.3 vs. 36.0 ± 14.3 years,

P

< .0017), less predominantly male (43% vs. 71%,

P

= .0005), less positive for hepatitis B e antigen (HBeAg) (23% vs. 60%,

P

< .0001), less infected with subgenotype Ae (0% vs. 13%,

P

< .05), and more frequently with Bj (30% vs. 4%,

P

< .0001) than those with acute self-limited hepatitis (n = 261). Precore (G1896A) and core-promoter (A1762T/G1764A) mutations were more frequent in patients with fulminant than acute self-limited hepatitis (53% vs. 9% and 50% vs. 17%,

P

< .0001 for both). HBV infection persisted in only three (1%) patients, and they represented 2 of the 23 infected with Ae and 1 of the 187 with the other subgenotypes (9% vs. 0.5%,

P

= .032); none of them received antiviral therapy. In multivariate analysis, age 34 years or older, Bj, HBeAg-negative, total bilirubin 10.0 mg/dL or greater, and G1896A mutation were independently associated with the fulminant outcome. In

in vitro

transfection experiments, the replication of Bj clone was markedly enhanced by introducing either G1896A or A1762T/G1764A mutation.

In conclusion

, persistence of HBV was rare (1%) and associated with Ae, whereas fulminant hepatitis was frequent (13%) and associated with Bj and lack of HBeAg as well as high replication due to precore mutation in patients with acute HBV infection.

Supplementary material for this article can be found on the HEPATOLOGY website
(http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).
Correlation between beta-lipoprotein levels and outcome of hepatitis C treatment
Authors: Gopal Kavitha , Johnson Timothy C. , Gopal Saraswathi , Walfish Aaron , Bang Christine T. , Suwandhi Pauline , Pena-Sahdala Helene N. , Clain David J. , Bodenheimer Henry C. , Min Albert D.
Published: July 2006

The low-density lipoprotein receptor (LDLR) has been proposed as a candidate receptor for the hepatitis C virus (HCV). Competitive inhibition of HCV binding to the LDLR by low-density lipoprotein (LDL) has been shown

in vitro

. If similar inhibition occurs

in vivo

, an elevated serum concentration of beta- lipoproteins may reduce the efficiency of infecting hepatocytes with HCV by competitively inhibiting HCV viral receptor binding. We investigated the role of baseline lipid values in influencing the outcome of HCV treatment. We conducted a retrospective chart review of patients treated with an interferon-based regimen at our liver and gastroenterology clinics between 1998 and 2004. Of 99 patients enrolled in the study, 49 (49.5%) had HCV genotype 1 (LDL 100.2 ± 30.2 mg/dL [mean ± SD]), and 50 patients (50.5%) had genotype 2 or 3 (LDL 110.1 ± 40 mg/dL) infection. Early viral response (EVR), end-of-treatment response (ETR), and sustained viral response (SVR) were documented in 99, 88, and 77 patients, respectively. LDL and cholesterol levels prior to treatment were found to be higher in patients with positive EVR, ETR, and SVR. This difference remained significant independent of age. Multivariate analysis controlling for genotype and age showed that the higher the cholesterol and LDL levels prior to treatment, the greater the odds of responding to treatment.

In conclusion

, having higher serum LDL and cholesterol levels before treatment may be significant prognostic indicators for treatment outcome of those with chronic hepatitis C infection, particularly in genotypes 1 and 2.
Loss of MMP 13 attenuates murine hepatic injury and fibrosis during cholestasis
Authors: Uchinami Hiroshi , Seki Ekihiro , Brenner David A. , D'Armiento Jeanine
Published: July 2006

Cholestasis occurs in a variety of clinical settings and often results in liver injury and secondary biliary fibrosis. Several matrix metalloproteinases (MMPs) are upregulated in the liver during cholestasis. The function of the major interstitial collagenase, MMP-13, in the initial phase of liver fibrosis is unknown. The aim of this study was to evaluate the role of MMP-13 during the development of cholestasis-induced liver fibrosis by comparing wild-type and MMP-13-deficient mice. Cholestasis was induced by bile duct ligation (BDL) for 5 days or 3 weeks. Activation and proliferation of hepatic stellate cells (HSCs) were detected by immunohistochemistry. Expression of MMP-13 mRNA increased significantly in BDL livers of WT mice. After BDL for 3 weeks liver fibrosis was suppressed in MMP-13-deficient mice versus WT animals. Activation and proliferation of HSCs were also suppressed in livers of MMP-13-deficient mice after BDL. To clarify the mechanism of this suppression, samples from 5-day BDL mice were used for evaluation of liver injury. Compared with those in WT animals, serum ALT and the number of hepatic neutrophils were reduced in MMP-13-deficient mice. Increased expression of the mRNA of inflammatory mediators such as tumor necrosis factor-alpha (TNF-α) was significantly suppressed in livers of MMP-13-deficient mice. Upregulation of fibrogenic markers, for example, transforming growth factor beta1 (TGF-β1), was also significantly suppressed in livers of MMP-13-deficient mice versus in WT mice.

In conclusion

, distinct from the known function of interstitial collagenase to reduce liver fibrosis by degrading the extracellular matrix, MMP-13 contributes to accelerating fibrogenesis in cholestatic livers by mediating the initial inflammation of the liver.
Immunosuppression using the mTOR inhibition mechanism affects replacement of rat liver with transplanted cells
Authors: Wu Yao-Ming , Joseph Brigid , Gupta Sanjeev
Published: July 2006

Successful grafting of tissues or cells from mismatched donors requires systemic immunosuppression. It is yet to be determined whether immunosuppressive manipulations perturb transplanted cell engraftment or proliferation. We used syngeneic and allogeneic cell transplantation assays based on F344 recipient rats lacking dipeptidyl peptidase IV enzyme activity to identify transplanted hepatocytes. Immunosuppressive drugs used were tacrolimus (a calcineurin inhibitor) and its synergistic partners, rapamycin (a regulator of the mammalian target of rapamycin [mTOR]) and mycophenolate mofetil (an inosine monophosphate dehydrogenase inhibitor). First, suitable drug doses capable of inducing long-term survival of allografted hepatocytes were identified. In pharmacologically effective doses, rapamycin enhanced cell engraftment by downregulating hepatic expression of selected inflammatory cytokines but profoundly impaired proliferation of transplanted cells, which was necessary for liver repopulation. In contrast, tacrolimus and/or mycophenolate mofetil perturbed neither transplanted cell engraftment nor their proliferation. Therefore, mTOR-dependent extracellular and intracellular mechanisms affected liver replacement with transplanted cells.

In conclusion

, insights into the biological effects of specific drugs on transplanted cells are critical in identifying suitable immunosuppressive strategies for cell therapy.
Hepatocellular carcinoma in ten children under five years of age with bile salt export pump deficiency
Authors: Knisely A. S. , Strautnieks Sandra S. , Meier Yvonne , Stieger Bruno , Byrne Jane A. , Portmann Bernard C. , Bull Laura N. , Pawlikowska Ludmila , Bilezikçi Banu , Özçay Figen , László Aranka , Tiszlavicz László , Moore Lynette , Raftos Jeremy , Arnell Henrik , Fischler Björn , Németh Antal , Papadogiannakis Nikos , Cielecka-Kuszyk Joanna , Jankowska Irena , Pawłowska Joanna , Melín-Aldana Hector , Emerick Karan M. , Whitington Peter F. , Mieli-Vergani Giorgina , Thompson Richard J.
Published: July 2006

Hepatocellular carcinoma (HCC) is rare in young children. We attempted to see if immunohistochemical and mutational-analysis studies could demonstrate that deficiency of the canalicular bile acid transporter bile salt export pump (BSEP) and mutation in

ABCB11

, encoding BSEP, underlay progressive familial intrahepatic cholestasis (PFIC)—or “neonatal hepatitis” suggesting PFIC—that was associated with HCC in young children. We studied 11 cases of pediatric HCC in the setting of PFIC or “neonatal hepatitis” suggesting PFIC. Archival liver were retrieved and immunostained for BSEP. Mutational analysis of

ABCB11

was performed in leukocyte DNA from available patients and parents. Among the 11 nonrelated children studied aged 13-52 months at diagnosis of HCC, 9 (and a full sibling, with neonatal hepatitis suggesting PFIC, of a tenth from whom liver was not available) had immunohistochemical evidence of BSEP deficiency; the eleventh child did not. Mutations in

ABCB11

were demonstrated in all patients with BSEP deficiency in whom leukocyte DNA could be studied (n = 7). These mutations were confirmed in the parents (n = 14). With respect to the other 3 children with BSEP deficiency, mutations in

ABCB11

were demonstrated in all 5 parents in whom leukocyte DNA could be studied. Thirteen different mutations were found.

In conclusion

, PFIC associated with BSEP deficiency represents a previously unrecognized risk for HCC in young children. Immunohistochemical evidence of BSEP deficiency correlates well with demonstrable mutation in

ABCB11

.
Bioindication and Functional Response in Floodplain Systems: Where to from Here?
Authors: Henle Klaus , Scholz Mathias , Dziock Frank , Stab Sabine , Foeckler Francis
Published: July 2006

We synthesise the results of the papers in this Special Issue, place them within the context of current trends in floodplain research, and outline promising new avenues that emerge from the contributions. The indication system presented complements existing approaches by focussing on a quantitative indication of environmental parameters. A promising research line that emerges is an extension of the systematic comparison of taxonomic groups with contrasting traits in terms of their performance as quantitative indicators for different environmental parameters. The studies show similarities and dissimilarities in the traits explaining the functional response of plants, molluscs, carabids, and syrphids to site conditions but trait databases and studies on additional taxa are required before broad generalisations can be made. The rigorous study design developed for the RIVA project, of which all contributions in this Special Issue are a part, not only was essential for an improvement of the understanding of species environment relationships and the role biological traits play for it, it also provides a baseline for assessing future change as part of long‐term ecological monitoring of floodplains. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of synthetic lubricating greases
Authors: Coffin P. S.
Published: July 2006

A fundamental characteristic of syntbetic lubricating greases is their price; all cost significantly more, sometimes by several orders of magnitude, than conventional mineral oil based greases. This fact is likely to remain true for the foreseeable future, given a stable supply situation for petroleum feed stocks. In consequence commercially, synthetic greases will only find use where improved performance characteristics over conventional greases justify their extra cost. There is a wide range of synthetic greases and each provides an individual performance profile. For specific applications with demanding performance requirements, one or more synthetic greases may offer considerable benefit over conventional greases. Thus synthetic greases are today being used in significant quantities, but only in those specific applications where the nature of the application places one or more demands on the lubricant that mineral oil based lubricants would find difficult to meet.
Oxidation and inhibition of pentaerythritol esters
Authors: Jensen R. K. , Korcek S. , Zinbo M.
Published: July 2006

Autoxidation and inhibited oxidation of pentaerythrityl tetraalkanoates, PETA, at elevated temperatures of 180 to 220°C have been investigated using a representative ester, pentaerytbrityl tetra heptanoate, PETH.1 In order to better understand reactions occurring in alkyl chains of PETA, similar studies were carried out with n‐bexadecane (HD), at 120 to 190°C.2,3 Based on the results of these studies, a general reaction scheme describing liquid phase autoxidation of organic compounds at temperatures of 120 to 220°C has been proposed.4 In this paper, kinetic and mechanistic information applicable to autoxidation of PETA is summarised and our recent contributions in the area of inhibition at elevated temperatures are reviewed.
Aliphatic dicarboxylic acid esters for synthetic lubricants
Authors: Debuan F. , Hänssle P.
Published: July 2006

Synthetic base oil components include mainly polyalphaolefins (PAO), dicarboxylic acid esters and polyol esters. In 1977, the world‐wide share of synthetic oils was about 0.5% of lubricant sales; today this is about 2%, and further annual growth rates of between 10 and 20%—relative to present consumption levels—are expected. The motor vehicle share of the synthetic oil market is about 30%, with the trend rising. In recent years, the literature has contained numerous reports on the general advantages and disadvantages of carboxylic acid esters. This standard knowledge is not repeated here. A few special and relatively new aspects are discussed, based on work carried out at VEBA Öl AG and Chemische Werke Hüls AG.
Synthetic lubricating greases for the food industry
Authors: Vámos E. , Neumann E.
Published: July 2006

The requirements of lubricating greases in the deep‐freezing industries, that lubricants do not undergo degradation of their lubricating properties, and the need for non‐aromatic and non‐toxic/non‐carcinogenic lubricants in food production, are discussed. Experimental data on the applicability of synthetic oils as bases for synthetic greases, are presented.
Air entrainment and foaming properties of synthetic lubricants at extreme temperatures
Authors: Hubman A. , Lanik A.
Published: July 2006

This paper examines the relationship between air retention (both by air entrainment and foaming) and lubricant characteristics. Laboratory research found that foaming is related to temperature; it may also be affected by other factors such as impurities. Data is presented on foaming properties and air separation for both mineral and synthetic oils. Foaming is also examined in relation to viscosity.
Recent developments in the performance properties of water based cutting and hydraulic fluids
Authors: Rudston S. G. , Whitby R. D.
Published: July 2006

Lubricants and functional fluids may be grouped into those based on natural oils and those having man‐made (‘synthetic’) base stocks. This paper is concerned with the ‘dilute synthetic lubricant’ in which the man‐made component is blended with a major proportion of water. The developments covered include hydraulic and metal‐cutting fluids, with examples drawn from experience with solutions and dispersions. The performance required from these fluids in service is discussed with particular attention to improvements in corrosion protection, antiwear performance, extreme‐pressure properties, foam inhibition, air release, rolling bearing fatigue and resistance to erosion pitting. Water quality can have a significant impact on the performance properties of the fluids already listed. The service properties of aqueous lubricants may be classified according to their response to chemical additives. Examples are given of properties which respond well to additives and of those which are governed largely by the bulk physical properties of water. Manufacturers of equipment are continuing to develop new machinery. Fluid formulators are seeking to extend the current operating limitations of aqueous fluids. Future development relies on close co‐operation between users, equipment suppliers and lubricant formulators.
Lubrication and cooling in electricity generating plant
Authors: Goodwin M. J.
Published: July 2006

This paper describes the lubrication and cooling systems of modern electricity generating plant, particularly those of the generator. The paper discusses the development of the power plant manufacturing industry and shows how critical the selection of lubricants and coolants is on the efficiency of the plant. The operation and layout of plant of up to 1,200 MW power rating are described and the various lubrication and cooling systems which are incorporated are identified. The cooling media discussed include non‐synthetic, semi‐synthetic, and synthetic fluids, and in each case the reasons for its selection are examined. Basic design calculations relating to lubrication and cooling systems are included. The paper concludes by examining trends in plant design and how they may affect future selection of lubricants and coolants.
Synthetic lubricants for turbocharged passenger cars
Authors: Neadle D. J.
Published: July 2006

This paper discusses the lubrication requirements of turbocharged passenger car engines and describes some of the experience obtained with petroleum based oils. Features of ester and polyalphaolefin synthetic lubricants are discussed in relation to the requirements of turbocharged engines. An attempt is made to review the present situation with regard to the lubricant types accepted by motor manufacturers and the implications of equipment design changes.
Catalysts for the synthesis of alphaolefin oligomer
Authors: Isa Hiroshi
Published: July 2006

The polymerisation method in the production of alphaolefin oligomer rests on the catalyst selected, and certain conditions are given that the method should fulfil. After a brief examination of the results of three kinds of catalyst, the Friedels‐Craft catalyst type is discussed in terms of production of medium, high and low viscosity alphaolefin oligomers.
Aviation turbine lubricant development
Authors: Bishop G. J.
Published: July 2006

This paper reviews the development of aviation turbine lubricants from the early days of jet propulsion and projects it through to the end of this century. Up to the present period, ester‐based synthetic oils have predominated, and largely fulfilled service requirements. However, ester‐based ‘Type 2’ lubricants are now perceived to be close to their optimum performance level and a new lubricant type will be required for the next generation of engines. The development of a ‘Type 3’ oil presents a great challenge to the aviation industry and could signal a departure from traditional routes of lubricant development.
Helicopter manufacturers' requirements for lubricating oils
Authors: Hartmann Joachim , Jonda Wolfgang
Published: July 2006

Experience with existing oils used in helicopters for transmissions, engines, hydraulics and brakes has shown that three main characteristics could drastically improve the performance of the aircraft.

These characteristics are: (1) the same type of oil should be usable for all the above mentioned systems; (2) the oil brands, produced to a common specification, but by different manufacturers, should be mixable without restrictions; (3) some features of the oil, which are specially important for helicopter operations, should be improved. Tests on mixed oils are reported, and recommendations made for future specifications.
Effect of lubricant on helicopter transmission efficiency
Authors: Coy John J.
Published: July 2006

Efficiency tests were conducted using eleven different lubricants in the NASA Lewis Research Center's 500 hp torque regenerative helicopter transmission test stand. The test transmission was the OH58A helicopter main transmission. The mechanical power input to the test transmission was 224 kW (300 hp) at 6060 r/min. Tests were run at oil‐in temperatures of 335°K (180°F) and 372°K (210°F). The efficiency was calculated from a heat balance on the water running through an oil‐to‐water heat exchanger while the transmission was heavily insulated. The test lubricants were analysed for their physical and chemical properties. Data on pressure‐viscosity characteristics as well as friction data from LFW‐1 type testing were examined for possible correlation with the efficiency data.

The following results were obtained. (1) Among the eleven different lubricants, the efficiency ranged from 98.3 to 98.8%, which is a 50% variation relative to the losses associated with the maximum efficiency measured. (2) for a given lubricant, the efficiency increased as temperature increased and thus as viscosity decreased. There were two exceptions which could not be explained on the basis of available data. (3) There was a reasonable correlation of efficiency with absolute viscosity (corrected for temperature and pressure in the contact). (4) Between lubricants, efficiency did not correlate well with absolute viscosity at atmospheric pressure. (5) Between lubricants, efficiency did not correlate well with calculated lubricant film forming capacity. (6) Bench type (LFW‐1) sliding friction and wear measurements could not be correlated to transmission efficiency and component wear. (7) The lubricants had no significant effect on the vibration signature of the transmission.
Solid lubricant additives for bismaleimide resin
Authors: Tewari U. S. , Sharma S. K. , Vasudevan P.
Published: July 2006

Bismaleimides are the addition type of polyimide resin. They are synthesized by reaction of diamino compounds with maleic anhydride. By varying the structure of the diamino compound it is possible to make various bismaleimides. This paper discusses improvement of the friction and wear properties of bismaleimide resin, by the addition of solid lubricant additives such as MoS2, graphite and PTFE.

The bismaleimide tested has the following structure: magnified image On heating, bismaleimide cross links through its unsaturated bonds, thus producing a highly cross linked polyimide. The friction and wear measurements were done on a Plint friction and wear machine (pin on disc type), wherein polymer pins slid against a steel disc at different loads and speeds.

The polymer itself had a high coefficient of friction, ranging from 0.3 to 0.6 and a higher wear rate. Solid lubricant additives helped in improving its friction and wear characteristics. The addition of graphite brought the coefficient of friction to 0.3 but wear remained high at high loads. Best results were obtained with additions to the resin of MoS2‐Sb2O3 and PTFE. Composites with MoS2‐Sb203 and PTFE had low coefficient of friction and low rate of wear, at low as well as at high loads. It appears that these solid lubricant additives transfer to the counterface, thereby reducing effective counterface roughness, hence reducing both friction and wear.
Fate of amine antioxidants during thermal oxidative ageing of neopentylpolyl ester oils
Authors: Zeman A. , Von Roenne V. , Trebert Y.
Published: July 2006

The main products of the thermal‐oxidative degradation of p, p'‐di‐tert‐ octyldiphenylamine, phenothiazine and 3,7‐di‐tert‐octylphenothiazine (DODPA/PTZ/DOPTZ) in pentaerythritol ester at 200°C were isolated and identified. Recombination o f aminyl radicals giving various dehydrodimers and dehydro‐trimers is obviously the dominating reaction in the primary stage of antioxidant depletion during ageing of inhibited ester oils. Minor degradation products include quinone imines, quinones, sulphoxides, phenoxazine and phenoxazone derivatives. Because of the complexity of the reactions product analyses are inevitably incomplete.
The effect of lubricant additives on friction and wear studies of polyphenylene sulphide
Authors: Tewari U. S. , Sharma S. K. , Vasudevan P.
Published: July 2006

Polyphenylene sulphide is a polymer with good thermal stability and high crystallinity. This paper summarizes the results of friction and wear studies of polyphenylene sulphide and its composites made with conventional solid lubricants to ascertain the suitability of the material as a matrix for solid lubricant additives. The polymer itself has a high coefficient of friction. Wear rate increases with load and speed. Addition of solid lubricant additives helps in improving the friction and wear of the polymer. Composites with MoS2‐Sb2O3 and PTFE gave better results than composites made by the addition of graphite and MoS2 graphite. Wear rate of these composites increased with load and speed; but load and speed had little effect on friction.
Precision instrument oils
Authors: Venkataramani P. S. , Srivastava R. D. , Kalra S. L. , Srivastava H. C.
Published: July 2006

Precision instrument mechanisms require highly specialized oils. These stringent requirements limit the choice of lubricants to synthetic types only. In this paper the physico‐chemical and peformance characteristics of a watch oil developed by the authors have been discussed to show how it meets the basic requirements of watch oils, and compares favourably with widely accepted watch oils. Where the test methods and test limits are at variance with the specification IS: 1088–1975 for watch and clock oils, commentary is given and suitable recommendations for modifying IS: 1088–1975 are made.
New developments in the field of synthetic lubricants from natural sources
Authors: Cosmacini E. , Vertuani M. L.
Published: July 2006

Oils derivedfrom natural sources like vegetable and animal fats are constituted by a variety of triglycerides. The major drawbacks as compared to petroleum lubricants is poor stability under operating conditions, caused by (1) presence of β‐hydrogen in the glyceride radical; (2) unsaturation in acyl radicals, which is linked to hydroxide formation and oxidation stability; (3) linear structure of the fatty acid which has poor resistance to hydrolysis and emulsification.

There are several reactions in oleochemistry by which the structure of triglycerides could be modified, and so liquids with good lubrication properties produced. These include hydrogenation, dimerization, alkylation, polyol formation and transesterification. This paper deals with the application of transesterfication for the modification of the glyceride structure into a lubricant. This permits preparation of a semisynthetic lubricant directly from natural glycerides. Molecular structure, molecular weight, polarity, rheological properties, thermal and hydrolytic stability of transesterification products are reported.
Energy conservation in stainless steel cold rolling applications
Authors: Ogura S. , Seki K.
Published: July 2006

In order to predict the performance of rolling oils in actual production mills, from tests in laboratory mills, the influence of various factors, such as shape factors work roll diameter (D), strip thickness (h1), operating conditions (reduction rate (r), peripheral velocity of roll (U0), strip velocity (U1)) and kinematic viscosity of the rolling oil (υ0) was investigated. A parameter RLI (Rolling Lubrication Index = u0(U0+U1)(1−r)(D/2h1.r)½) was found to be useful in predicting lubricating conditions in actual production mill applications.

The coefficients of friction of mineral oils, some synthetic hydrocarbons including polybutene, and several kinds of additives were obtained from laboratory mills under the same condition of RLI value as that for finish rolling in actual production mills. With hydrocarbons, paraffins showed the lowest coefficient offriction, while aromatics exhibited a higher coefficient of friction, with naphthenes showing the highest.

A high‐quality rolling oil was formulated using a combination of ester and paraffinic mineral oil. It is observed that this new oil can save 14% of energy consumed by a laboratory mill compared with conventional rolling oils. In production mills, nearly the same energy conservation level can be achieved.
Sxynthesis and properties of adamantane synthetic lubricants
Authors: Podehradskà J. , Vodička L. , Štěpina V.
Published: July 2006

Adamantane hydrocarbons and esters have already been described in the literature. This paper examines the properties of two types of adamantane oils, tri‐ and tetrabutyladamantanes, and esters prepared from adamantyl methanols and aliphatic acids, and alkyladamantane carboxylic acids and aliphatic alcohols. The preparation, properties and in particular the electrical properties are presented.
Friction and wear studies of an internally lubricated polyetherimide composite
Authors: Bijwe J. , Tewari U. S. , Vasudevan P.
Published: July 2006

Polyetherimide (PEI) is one of the latest generic high‐performance engineering thermoplastics. PEI (developed by General Electric (USA) under the trade name ULTEM) is an amber and amorphous polymer with a heat distortion temperature between those of polyarylate resin and thermally stable crystalline polymers such as polyether‐ether ketone (PEEK) and polyamideimide (PAI). It has excellent thermal, mechanical and electrical properties along with easy processability. In the work reported here, a wear‐resistant formulated composite supplied by GEC (ULTEM 4001) was selected for tribological investigations on a pin on disc machine under unlubricated conditions, against mild steel. Analysis of the composite revealed that this grade contained PTFE (13–15%), which is the most promising polymeric lubricant.

A very low and stable frictional coefficient was observed against moderately finished surfaces. However, its specific wear resistance (⋍10−14 m3/Nm) was comparatively lower than that of fibre‐reinforced thermoplastics. The wear mechanism was found to be significantly dominated by the presence of PTFE. The friction coefficient was in the range of 0.2 and reduced to a still lower value (0.1) as the apparent contactpressure increased. Scanning electron microscopy was used to investigate the underlying wear mechanism. Film transfer of PTFE was observed to be the principal factor responsible for reduced friction.
Deuterated grease thickener
Authors: Conte Alfeo A.
Published: July 2006

The ‘Deuterium Isotope Effect’ was investigated as a means of further increasing the oxidation resistance of soap‐thickened greases utilized in miniature bearing applications. Using lithium stearate as a model compound, the bearing performance life and induction period for oxidation were determined on four different greases prepared from non‐deuterated and deuterated base oil and thickener. The expected increase in oxidation resistance and bearing performance life was observed for the deuterated base fluid; however, the use of a deuterated thickener did not provide any significant improvement. Details concerning the preparation of thickener and grease formulations and their properties are presented.
Water‐based hydraulic fluids containing synthetic components
Authors: Rasp C. R.
Published: July 2006

This paper explains the nature offire‐resistant, water‐based hydraulic fluids, and their applications, and gives comparisons with mineral oil‐based hydraulic fluids. The content of the different types of fluid is described, and the technical requirements for water‐based hydraulic fluids discussed. The chemistry of the synthetic thickeners of water, their thickening effect and shear stability, as well as their technical properties, are explained and compared. The construction and the mode of action of thickeners for hydraulic fire‐resistant fluids (HFAS) or viscous high‐water‐based fluids (VHWBF) are detailed, and the physical chemistry of these hydrophilic‐hydrophobic thickeners, which form microemulsions in water, is considered in interaction with emulsifying agents. In this case laser‐light scattering correlation spectroscopy is shown to be helpful.
Thermal stability of synthetic oils in aviation applications
Authors: Koch B.
Published: July 2006

The thermal decomposition of selected synthetic base fluids has been investigated. The effects of temperature and time on the rate and extent of thermal degradation were studied in a modified steel bomb test device. The effects of chain length and branching are important factors in the thermal stability of hydrocarbons and similar fluids. In order to overcome the 350°C limit of thermal stability, other classes of chemical have to be used.
Development of a meta‐stable semi‐synthetic lubricant for cold rolling of steel
Authors: Mahanti S. , Bhatta A. K. , Biswas R. N. , Bhatia J. , Singh S. N.
Published: July 2006

A semi‐synthetic meta‐stable oil system for cold rolling of steel was developed as a substitute for a mineral oil based ‘stable emulsion’‐type soluble oil. The developed oil system, comprising a ‘coating oil’ for post‐pickling application and a ‘rolling oil’ for the rolling operation, was tested in the laboratory and subsequently subjected to extensive field trials in an integrated steel plant. Use of the developed oil system resulted in 25–50 per cent lower roll loads and 30–50 per cent reduction of inter‐stand tensions compared with the mineral oil‐based ‘stable emulsion’. It was also possible to increase the ‘strip reduction ratio’ and input coil width with the use of the newly‐developed oil. Overall performance of the new semi‐synthetic oil was found to be far superior to that of the mineral oil based ‘stable emulsion’.
Influence of cutting fluids on surface finish of holes drilled into aluminium 390
Authors: Leep Herman R.
Published: July 2006

The primary objective of this research was to compare the surface finish resulting when using a semi‐synthetic cutting fluid to that of a premium soluble oil. The secondary objective was to determine the effects of drill diameter, cutting speed, and fluid concentration on surface finish.

The surface measurements were made on the walls of 6.350 and 9.525 mm lind holes drilled 25.4 mm into aluminium 390. Each cutting fluid was introduced using a flood application. Additional factors in the experimental design for each cutting fluid included two levels of cutting speed and two levels of fluid concentration.

Variations in drill diameter, cutting speed, and the interaction between these factors were significant with respect to surface finish for both the semi‐synthetic fluid and the soluble oil. Fluid concentration for the semi‐synthetic fluid also had a significant effect on the surface finish. The surface finish produced while using the semi‐synthetic fluid was approximately the same as that with the soluble oil.
Analysis and quality control of aviation turbine oils
Authors: Bartl P. , Seinsche K.
Published: July 2006

A method is described in which capillary gas chromatographic data from aviation turbine oils are processed by methods of pattern recognition based on the chemometrics systempackage ‘Ein*Sight’. It allows an automatic, objective and quantitative comparison of the base oil components of production batches. This application can be used to advantage in a control scheme based on analytical data.
Optimal preparation conditions for some diester based synthetic lubricants
Authors: El‐Magly I. A. , Nasr E. S. , El‐Samanoudy M. S.
Published: July 2006

In this paper, work is reported on the esteriflcation of various materials, where di‐2‐ethythexyl esters of succinic, adipic, azelaic and sebacic acid were prepared. Water produced by the reaction was separated continuously and the reaction progress was followed up by measurement of the acid content. Factors affecting the esterification were studied and the optimal conditions for conversion of about 92% to 95% (by weight) were found to be: temperature — 179°C; molar ratio of add to alcohol — 1:2.4; catalyst concentration — 3% (by weight) based on acid; agitation rate — 350 r/min.
Testing the elastomer compatibility of aviation turbine oils
Authors: Uedelhoven W.
Published: July 2006

This paper covers different parameters influencing the elastomer compatibility of aviation turbine oils. It looks first at the chemistry of rubbers and oils, and then at the chemistry and physics of the interactions of elastomer thermodynamics and oils. The applicability of theory is then demonstrated and judged by means of a practical example.
The application of synthetic fluids to automotive lubricant development: Trends today and tomorrow
Authors: Coffin P. S. , Lindsay C. M. , Mills A. J. , Lindenkamp H. , Fuhrmann J.
Published: July 2006

Engineering design of the internal combustion engine is under a constant state of evolution which has been driven by many factors. These design changes have led to higher performance requirements from the lubricant, e.g. greater resistance to thermal and oxidative degradation, improved deposit and sludge control, and increased control of volatility. Mineralbased lubricants have traditionally proved successful for the vast majority of automotive applications. The current advances have stretched such products to the limit of their capabilities. In such areas, it has been found that synthetic lubricants offer benefits far outweighing their higher costs, providing clearcut performance benefits for the modern generation of higher‐performance vehicles. The current state of the art is reviewed from both application and chemical standpoints, and future trends are projected in the light of ongoing developments.
Synthetic lubricants in cold strip rolling
Authors: Lenard J. G.
Published: July 2006

The embedded‐pin technique is used to monitor the variation of the interfacial forces during cold rolling of aluminium slabs. The results confirm earlier conclusions, indicating that the frictional coefficient is a strong function of the process and material parameters. Coefficient of friction values deduced from forward slip measurements are close to the present data, confirming that in spite of several drawbacks of the experimental technique, it can yield very useful results. Lubricants are shown to reduce the loads on the rolling mills in a significant manner.
Improvement of antioxidation and antiwear properties of polyalphaolefin oils
Authors: Shkolnikov V. M. , Zvetkov O. N. , Chagina M. A. , Kolessova G. V.
Published: July 2006

Polyalphaolefin‐based lubricating oils were tested on a four‐ball tester, and in a stability test, with antiwear and antioxidant additives of different types, along with other (petroleum and alkylbenzene) base oils and additives. Antioxidant additives for PAOs essentially influence their thermo‐oxidation stability. It was found that binary inhibitors increased thermo‐oxidation stability effectively. In the antiwear tests, the addition of additives to PAOs sharply decreased wear scar diameters. A significant difference was observed in the action of small concentrations of antiwear additives as between PAO, alkylbenzene and mineral oils. Explanations of this behaviour are put forward.
Precision bearings and their tribological simulation
Authors: Stehr W.
Published: July 2006

Reliable laboratory simulation of the tribological conditions that lubricated sliding bearings face in the field requires the use of computer assisted test procedures. The example of lubricated plastic bearings given here illustrates the use of relational database systems combined with automated data analysis, and shows its relevance for practical applications.

To predict the functioning of lubricated platic bearings, a multiple of test procedures and laboratory methods are necessary due to the large variety of synthetic lubricants and the multiple of plastics. Each test procedure generates a considerable amount of individual data. From these data, the information relevant for each particular application must be extracted. This procedure can be speeded up by using a database, and indeed some of it is only possible with the use of a database. This database acts as the central place for data collection. By using specific commands, with actual parameters acting as filters, the necessary information can be retrieved. The efficiency of tribological testing and its immediate relevance for the field is thereby greatly enhanced.
Synthetic lubricants for air cooled two cycle engine oils: Effect of esters on lubrication and tribological properties
Authors: Moura D. , Légeron J.‐P.
Published: July 2006

This paper reports the development of an air‐cooled two‐stroke engine lubricant using esters as synthetic base stocks, and performance additives. The viscosimetric and terminological properties as well as the performance in two‐cycle gasoline engines are described in comparison with standard lubricants. It is shown that the use of suitable esters can make possible the formulation of high performance lubricants for the severity of use.
A study of greases based on polyureas
Authors: Liangsen Xie , Hui Li
Published: July 2006

This paper illustrates the thickening effects of diureas and tetraureas formed from monoamines, diamines and diisocyanates on the mineral oils of different viscosity, and on the esters and polysiloxanes of different structures. It also reviews the properties and applications of such greases based on polyureas.
A study of the viscosity‐temperature relationship of synthetic lubricants
Authors: Yang‐Wu Zhang
Published: July 2006

Various workers have developed different viscosity ‐temperature relationships for fluids for many years. These relationships are suitable for a narrow temperature range, but they are unsuitable over the wide temperature ranges of synthetic lubricants. This paper describes a modified ASTM 0341 viscosity‐temperature relationship developed by a least‐squares treatment of large amount of available experimental viscosity data for synthetic lubricants. The modified relationship reads:

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The relationship can adequately describe viscosity‐temperature characteristics of synthetic lubricants over a wide temperature range. The relationship was examined for various synthetic lubricants. It was found capable of correlating the available experimental viscosity data with an average absolute error of less than 2% between calculated values and experimentally determined values over the temperature ranges studied for 14 synthetic lubricants.
A novel family of traction fluids deriving from molecular design
Authors: Dare‐Edwards M. P.
Published: July 2006

An investigation has been undertaken into the fundamental molecular design features that may be seen to correlate with high traction coefficients of lubricants operating under elastohydrodynamic conditions. With the assistance of computer‐aided molecular mechanics modelling, a novel family of fluids has been designed which display excellent tractional performance. Prospects for the further development of these modelling techniques and also the practical usage of the designed fluids are discussed.
Comparison of synthetic aromatic oil and crude oil resistances against the influence of nuclear radiation
Authors: Kostolányi Peter , Szücs Ladislav , Ruman Ján
Published: July 2006

The use of lubricants in conditions of radiation, as in nuclear power installation, poses certain problems for the stability of the lubricant. These include (1) changes in viscosity, (2) evolution of gases, (3) in air, accelerated oxidation, (4) secondary effects such as separation of additives and demulsibility deterioration. In this paper are reported the results of experiments on changes in kinematic viscosity and acid base number of mineral base oils and a synthetic oil.
Effect of temperature on the friction and wear of heat‐resistant polymer‐based composites
Authors: Tanaka Kyuichiro , Yamada Yoshinori , Ueda Seiichi
Published: July 2006

The friction and wear of polyether sulphone (PES: ‘Victrex’‐ICI), polyether etherketone (PEEK: ICI), polyamide‐imide (PAI: Torlon'‐Amoco) and Polytetrafluoroethylene (PTFE) composites were measured at a constant sliding speed and under a constant load at various temperatures up to 300 °C by rubbing against a steel disc. The frictions of the composites, except for some PAI composites, were generally little dependent upon temperature over a wide range of temperature. PTFE filler was effective in reducing the wear of composites at high temperatures. However, the addition of various fibres to the composites was not effective at high temperatures. The wear of PAI composites increased rapidly with increasing temperature and thus their temperature variations were considerably greater than those of the other composites. The wear of PTFE containing ‘Econol’ E–1 OI, a polyoxybenzylene nomo‐polymer (Sumitomo Chemical Co.) and graphite was similar to that of the PEEK composite containing PTFE, and their wear rates were remarkably low over a wide range of temperature. The wear‐reducing mechanisms of PTFE and ‘Econol’ fillers are discussed on the basis of microscopic examinations of the frictional surfaces.
Some experimental studies of lubricants in a two‐stroke methanol engine
Authors: Chadha B. R. , Gupta Mukesh , Gupta L. R. , Maji S. , Singhal S.
Published: July 2006

A two‐stroke cycle scooter engine modified to operate on methanol fuel has been tested. Castor and synthetic oil formulations were identified as potential lubricants. A formulation based on polypropylene glycol (PPG) has demonstrated excellent miscibility in methanol fuel. It also performed well in engine tests, especially with reference to piston tightening and deposit forming tendencies.
A mechanism of thermo‐oxidative degradation of polyol ester lubricants
Authors: Bakunin V. N. , Parenago O. P.
Published: July 2006

Polyol ester lubricants are used in a wide range of temperature conditions, normally from −54 up to +220 °C, and their application can be limited by high temperature oxidation leading to viscosity increase, sludge, and/or formation of deposits. This paper is concerned with the chemical processes which take place during the oxidation of esters, particularly polyol esters, and discusses the selectivity of oxygen attack on ester molecules, and the formation and decomposition of hydroperoxides as well as other products formed as a result of ester oxidation. Proposed mechanisms of polyol ester lubricant oxidation are discussed, and unresolved problems which require additional research efforts are revealed.
Perfluoropolyether lubricants
Authors: Corti C. , Savelli P.
Published: July 2006

This work reports the physico‐chemical characteristics, the tribological characteristics and additive susceptibility of two series of perfluoropolyether fluids and greases, one obtained from hexafluoropropene, the other from tetrafluoroethene. Some applications of perfluoropolyether lubricants are considered.