High Molecular Weight

Teaoil Camellia (Camellia oleifera Abel.) is a promising horticultural crop that has been cultivated for various purposes in China for more than 1000 years. It is a small tree, which grows naturally from latitudes of 18° to 34° North and in acidic soils where January mean temperatures do not drop below 2°C. As cooking oil, it compares favorably with olive oil, stores well at room temperature, and has a high smoke temperature. Teaoil is also used in the manufacture of soap, margarine, hair oil, lubricants, paint, rustproof oil and other compounds with a high-molecular weight as well as in cosmetology and dermopharmacy. Extracts from the residues of teaoil processing have been used in livestock feeds, pesticides and fertilizers. The use of tea oil products in controlling rice blast and wheat rust also suggests potential for the development of new biological-based pesticides from this plant. Although edible tea oil production covers about 40,000 km 2 in China, other countries know little about this species, only planting it as an ornamental plant. To share this valued crop to the world, selecting promising clones for targeted habitats is the key to success. Cloning propagation using hypocotyl grafting is recommended. Management practices, such as preparing planting sites with organic fertilizer, controlling weeds, thinning, pruning, alternating harvest time, improving harvest techniques, etc., could significantly increase the economic return for C. oleifera plantations. Further studies on the genetic improvement of tea oil will improve its popularity around the world.

Milling and baking tests were carried out on three transgenic wheat lines and their parental varieties grown in the field at two UK sites. The transgenic and control lines were essentially similar in their milling properties but the subunit 1Ax1 and 1Dx5 transgenes had different effects on breadmaking. The subunit 1Dx5 transgene resulted in a low loaf volume and poor crumb structure when expressed in lines with two or five endogenous HMW subunits, and this was accompanied by a greatly increased elastic modulus of the gel protein fraction. In contrast, the 1Ax1 transgene resulted in improved breadmaking quality and a more modest increase in the gel protein elastic modulus when expressed in the two subunit background. Blending of flour from a line expressing the 1Dx5 transgene with flour from a normal breadmaking wheat variety resulted in decreased breadmaking quality, even at a ratio of 1:9. The difference in the results obtained with the 1Ax1 and 1Dx5 transgenes may relate to the presence of an additional cysteine residue in the protein encoded by the latter, which promotes a more highly cross-linked glutenin network.

We present a complete DNA sequence and metabolic analysis of the dominant oral bacterium Fusobacterium nucleatum. Although not considered a major dental pathogen on its own, this anaerobe facilitates the aggregation and establishment of several other species including the dental pathogens Porphyromonas gingivalis and Bacteroides forsythus. The F. nucleatum strain ATCC 25586 genome was assembled from shotgun sequences and analyzed using the ERGO bioinformatics suite (http://www.integratedgenomics.com). The genome contains 2.17 Mb encoding 2,067 open reading frames, organized on a single circular chromosome with 27% GC content. Despite its taxonomic position among the gram-negative bacteria, several features of its core metabolism are similar to that of gram-positive Clostridium spp., Enterococcus spp., and Lactococcus spp. The genome analysis has revealed several key aspects of the pathways of organic acid, amino acid, carbohydrate, and lipid metabolism. Nine very-high-molecular-weight outer membrane proteins are predicted from the sequence, none of which has been reported in the literature. More than 137 transporters for the uptake of a variety of substrates such as peptides, sugars, metal ions, and cofactors have been identified. Biosynthetic pathways exist for only three amino acids: glutamate, aspartate, and asparagine. The remaining amino acids are imported as such or as di-or oligopeptides that are subsequently degraded in the cytoplasm. A principal source of energy appears to be the fermentation of glutamate to butyrate. Additionally, desulfuration of cysteine and methionine yields ammonia, H 2 S, methyl mercaptan, and butyrate, which are capable of arresting fibroblast growth, thus preventing wound healing and aiding penetration of the gingival epithelium. The metabolic capabilities of F. nucleatum revealed by its genome are therefore consistent with its specialized niche in the mouth. Fusobacterium nucleatum is a gram-negative anaerobe, which belongs to the Bacteroidaceae family and is found naturally in the microflora of the mouth in healthy or diseased humans. F. nucleatum is a very long rod with tapering ends and is one of the dominant species of the 500 or more organisms that coexist in the oral cavity (21). Many of the oral flora are commensals but a few are opportunistic pathogens. F. nucleatum can be isolated not only from the mouth but also from infections such as skin ulcers, peritonsillar abscesses, septic arthritis, and endocarditis (5). Several species of Fusobacterium have been isolated and studied, including F. necrophorum (the causative agent of Lemierre's syndrome), F. ulcercans (skin ulcers), F. russi (animal bite infections), and F. varium (eye infections), with F. nucleatum and F. necrophorum considered to be the most pathogenic. In the initial stages of the periodontal disease process, saccharolytic, aerobic Streptococcus spp. and other bacteria adhere to and colonize the tooth enamel and root surface. This sets the stage for F. nucleatum to coaggregate with these early colonizers and to permit late colonizers, including dental pathogens, to eventually form a biofilm. These complex interactions result in the release of factors that lead to tooth decay. Physical interaction is very specific among various genera in this complex microbial community. Due to the unusual length, adhesive nature, and other cell surface properties of F. nucleatum, periodontal disease-causing bacteria such as Porphyromonas gingivalis, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Treponema denticola, and Streptococcus spp. aggregate and thrive; hence, F. nucleatum is referred to as a "bridge bacterium" (5). The interaction between F. nucleatum and P. gingivalis has been reported to be very specific (19), mediated by a lactose-binding adhesin (20). The same adhesin protein mediates the binding of F. nucleatum to a variety of eukaryotic cell types including HeLa cells, buccal epithelial cells, macrophages, polymorphonuclear leukocytes, and gingival and periodontal ligaments (46). Helicobacter pylori was also shown to adhere selectively to F. nucleatum (1). Research on Fusobacterium spp. has focused primarily on species identification, oral ecology, cell-cell communication, extracellular surfaces, amino acid degradation, carbohydrate metabolism, organic acid fermentation, and antibiotic resistance (5, 21). However, many metabolic pathways and their roles in survival in such specialized niches are not known. Genetic experiments have been hampered by the lack of molecular tools, although recently three plasmids, pFN1, pFN2, and pFN3, have been isolated and sequenced from the strain ATCC 10953. A transformation system has been developed for gene manipulation using the pFN1 ori sequence (14). Although many potential virulence candidates have been

High molecular weight (HMW) hydrocarbons (>C 40) and asphaltenes are important constituents of petroleum and can cause problems related to crystallization and deposition of paran waxes during production and transportation as well as in the formation of tar mats. However, traditional methods to isolate asphaltene fractions, by adding 40 volumes in excess of low boiling point solvents such as pentane, hexane or heptane, can produce asphaltene fractions which are contaminated with a signi®cant amount of microcrystalline waxes (>C 40). The presence of these microcrystalline waxes in the asphaltene fractions has the potential to provide misleading and ambiguous results in modeling and treatment programs. The sub-surface phase behaviour of an asphaltene fraction will be quite dierent from that of a wax-contaminated asphaltene fraction. Similarly accurate modelling of wax drop-out requires information on pure wax fractions and not asphaltene-dominated fractions. Hence the goal of this paper is to describe a novel method for the preparation of wax-free asphaltene fractions. In addition, this method provides a quantitative subdivision of the wax fraction into pentane soluble and insoluble waxes which, when correlated with physical properties of crude oil such as viscosity, pour point, cloud point, etc., may help explain causes of wax deposition during production, transportation and storage of petroleum.

The purpose of this study was to determine the absorption, distribution and excretion of 99mtechnetium-labeled, high-molecular-weight hyaluronan ((99mTc-HA) and 99mtechnetium pertechnetate (99mTc-P) after single dose, oral administration to Wistar ...

This paper presents the synthesis and characterization of an original class of supramolecular networks, the 'sliding' gels. In this new class of network materials the crosslink points are not fixed but sliding. The molecular structure is based on intermolecularly crosslinked acyclodextrins/poly(ethylene-glycol) precursor polyrotaxanes. A synthetic method was developed to obtain various high molecular weight precursor polyrotaxanes with various amounts of a-cyclodextrins (a-CD) per template chain (the so-called degree of complexation, N). The crosslinking reaction of the precursor polyrotaxanes was carried out with the divinyl-sulfone allowing an efficient and good control of the crosslinking density. This control permitted to obtain various network materials with unusual physical/mechanical properties depending on the crosslinker amount and on N. The unusual properties originate from the sliding character of the crosslink points, in these new network materials, which induces a variable and eventually controllable mean mass distribution of the entanglement length. The mechanical spectroscopy and rheological experiments showed two viscoelastic regimes evidencing the molecular mechanism of the change of the mean mass distribution between the crosslink points due to the sliding of a-CD rings on the template PEG chain.

High pressure thermal treatment (HPTT) is a new process developed by BTG and University of Twente with the potential to economically reduce the oxygen and water content of oil obtained by fast pyrolysis (pyrolysis oil), properties that currently complicate its co-processing in standard refineries. During the HPTT process, pyrolysis oil undergoes a phase split yielding a gas phase, an aqueous phase and an oil phase. In this study, HPTT experiments were carried out at different operating conditions in a continuous tubular reactor. Experimental results showed that, with increasing temperature and residence time, the release of gases (mainly CO 2) and the production of water increased, reducing the oxygen content of the oil phase and hence increasing the energy content (from 14.1 to 28.4 MJ/kg) having the temperature a larger effect when compared to the residence time. Using gel permeation chromatography (GPC), an increase of the molecular weight of the oil phase, probably due to polymerisation of the sugars present in pyrolysis oil, was observed. When water was added as solvent to dilute the feed oil, a decrease of the molecular weight of the resulting oil phase was observed. This indicated that the concentration of organic components had a direct effect on the formation of high molecular weight components. In conclusion, during HPTT an oil with lower oxygen and water content with higher energy value was produced, but adverse formation of high molecular weight components was also detected.

The effects of barley and oat b-glucans on rheological and creaming behaviour of concentrated egg-yolk-stabilized model emulsions were investigated. Four polysaccharide preparations were used, two from each cereal; one sample with high and one with low molecular weight, i.e. the molecular weights were alike in pairs (, 110 £ 10 3 and , 40 £ 10 3 , respectively). In order to elucidate the mechanism of action of b-glucans in emulsions, Tween 20-stabilized emulsions were also examined. Tween 20 enhances neither the continuous phase viscosity nor the interactions between the droplets, so the changes could be easily attributed to b-glucans. It appeared that the low Mw b-glucan samples stabilize emulsions against creaming by means of network formation in the continuous phase while their high molecular weight counterparts enhance the viscosity of the continuous phase. Comparison of dynamic rheological tests between a reference emulsion without b-glucans and emulsions containing b-glucans showed that the polysaccharides largely affects the viscoelastic behaviour of the emulsion. Ageing of b-glucan-containing emulsions did not affect significantly the viscoelastic properties except for the emulsions containing low Mw b-glucans extracted from oat. Interestingly, all emulsions containing b-glucans creamed approximately the same after 30 days of storage regardless which preparation was used. The egg yolk constituents seemed to play a dominant role on the viscoelastic and the creaming behaviour of the emulsions, i.e. the viscoelastic behaviour was further enhanced and this could not only be attributed to the presence of the b-glucans but also to the stronger interactions between the oil droplets. Ageing did not affect the viscoelastic properties of b-glucan-containing emulsions while the reference emulsion, prepared only with egg yolk, showed a decrease in the value of storage modulus. The former could be interpreted as a steady consistency of the product during storage independent of the creaming behaviour. The creaming behaviour varied among the samples with the high molecular weight b-glucans from oat showing the highest stability. q

It is well known that polypropylene undergoes simultaneous crosslinking and degradation under irradiation. However, there are speculations regarding the formation of branching under special conditions. It is also well known that the melt-strength property of a polymer increases with molecular weight and with long-chain branching due to the increase in the entanglement level. This study was a contribution to the

Ultra-high molecular weight polyethylene (UHMWPE) thin film was coated onto Ti6Al4V alloy specimens using dip coating method. Tribological performance of this coating (thickness of 19.6 ± 2.0 µm) was evaluated using 4 mm diameter Si 3 N 4 ball counterface in a ball-on-disk tribometer. Tests were carried out for different normal loads (0.5, 1.0, 2.0 and 4.0 N) and rotational speeds of the disk (200 and 400 rpm). UHMWPE coating formed in this study exhibits high hydrophobicity with water contact angle of 135.5 ± 3.3 • and meets the requirements of cytotoxicity test using the ISO 10993-5 elution method. This coating shows low coefficient of friction (0.15) and high wear durability (>96,000 cycles) for the tested conditions. PFPE overcoat on UHMWPE has further increased the wear durability of UHMWPE coating as evaluated at even higher rotational speed of 1000 rpm. c

Hematuria caused by prerenal, glomerular, postglomerular, and postrenal causes is usually differentiated by a number of noninvasive and invasive diagnostic procedures. In the present study we have applied a new analytical strategy based on observations that the various forms of hematuria can be classified by their typical protein pattern. When analyzed by quantitative turbidimetric assays, urines from postrenal hematurias contained high-molecular-weight proteins (~2-macroglobulin and IgG) in proportions found in plasma. Relating excretion rates (mg/mg) of these proteins to those of albumin, ratios for c~2-macroglobulin/albumin and IgG/albumin were 2.0-31 x 10 .2 and 20.0-180x 10-2, respectively. In contrast, glomerular hematurias exhibited ratios of 0.01-2.0 x 10-2 (~2macroglobulin/albumin) and 2.0-20 x 10-2 (IgG/ albumin). Additional determination of ~-microglobulin allowed us to differentiate postglomerular hematurias caused by interstitial nephropathies from glomerular and postrenal diseases. Critical evaluation of 93 cases diagnosed by independent clinical examination including histology, sonography, and cystoscopy revealed that the criteria derived from protein measurements resulted in correct classification when urine albumin exceeds 100 mg/l. This noninvasive procedure is expected to be of considerable help in the primary care of patients with unexplained hematuria.

Ultra high molecular weight polyethylene (UHMWPE) is a semicrystalline polymer that has been used for over four decades as a bearing surface in total joint replacements. The mechanical properties and wear properties of UHMWPE are of interest with respect to the in vivo performance of UHMWPE joint replacement components. The mechanical properties of the polymer are dependent on both its crystalline and amorphous phases. Altering either phase (i.e., changing overall crystallinity, crystalline morphology, or crosslinking the amorphous phase) can affect the mechanical behavior of the material. There is also evidence that the morphology of UHMWPE, and, hence, its mechanical properties evolve with loading. UHMWPE has also been shown to be susceptible to oxidative degradation following gamma radiation sterilization with subsequent loss of mechanical properties. Contemporary UHMWPE sterilization methods have been developed to reduce or eliminate oxidative degradation. Also, crosslinking of UHMWPE has been pursued to improve the wear resistance of UHMWPE joint components. The 1 st generation of highly crosslinked UHMWPEs have resulted in clinically reduced wear; however, the mechanical properties of these materials, such as ductility and fracture toughness, are reduced when compared to the virgin material. Therefore, a 2 nd generation of highly crosslinked UHMWPEs are being introduced to preserve the wear resistance of the 1 st generation while also seeking to provide oxidative stability and improved mechanical properties.

The molecular weight distribution has been determined for the galactomannan solubilized from three types of locust bean gum (LBG) flours: single carob seeds, mixtures, and a range of commercial products. To prepare crude endosperm flours from carob seeds with minimal galactomannan degradation, a new extraction and milling method was developed. The method consists of applying a brief thermal shock to the seeds, followed by an extended 3-day swelling period, and manual separation of endosperms; particle size reduction to a flour is accomplished on hydrated endosperms using a centrifugal mill. This method was optimized so that redissolved LBG flours produced solutions with the highest possible viscosity and the least amount of galactomannan degradation as determined by SEC. For the three samples types, the molecular weight distribution, w(M), was found to be unimodal, appearing as a sharply defined main peak (M p E1.1 Â 10 6 g/mol) with a small high molecular weight tail (up to 2.0 Â 10 6 g/mol) and broad low molecular weight tail (down to 0.01 Â 10 6 g/mol); polydispersities (M w /M n ) were estimated to be 1.5-1.8. Variations in M w and [Z] for galactomannans extracted from individual seeds originating from the same carob tree were minimal and nearly indistinguishable from a bulk mixture (6 seeds, M w ¼ 0.96-1.1 Â 10 6 g/mol, [Z] ¼ 14.2-15.1 dl/g). There was a higher variability in these molecular parameters for galactomannans solubilized from commercial LBG flours, which generally exhibited lower M w and [Z], broader distributions, and reduced solubilities (M w ¼ 0.86-1.0 Â 10 6 g/mol, [Z] ¼ 12.4-13.6 dl/g). These side-effects were attributed to damage caused by industrial scale seed processing. The near constancy of M p for the three sample types suggests that the average molecular size of LBG galactomannan varies only slightly due to natural or biological causes. r

The isolation of DNA from whole blood by a modified rapid method (RM) was tested using various detergents and buffer conditions. Extraction of DNA with either NP-40 or Triton X-IO0 gave a high yield of undegraded DNA in less than an hour. The concentration of magnesium ion in the buffers was critical to obtaining intact, high molecular weight (HMW) DNA. Greater than 10 mM MgCl2 led to degradation. Addition of EDTA to the buffer inhibits this degradation. Preparation of DNA from blood stored at room temperature or incubated at 37~C for 24 hr resulted in the same amount and quality of DNA as from samples frozen at -70°C. DNA from blood samples that had undergone more than four freeze-thaw cycles was found to be pal¢ially degraded. The modified RM can be applied to extract DNA from as little as 10 ixl of blood (340 ng of DNA) and from dried blood samples. DNA samples remained intact and undegraded for longer times when DNA was dissolved in higher concentrations of EDTA.

This review describes various studies of marine plutonium distributions, behaviour and transfer carried out at the Marine Environment Laboratory of IAEA. Plutonium in sea water is primarily present in solution as Pu(V), probably as PuO+2, and on particles in reduced form as Pu(IV), most likely as species such as adsorbed Pu(OH)4. In nearshore sediments and coastal soils, plutonium is complexed with high molecular weight humic and low molecular weight fulvic compounds. Results of oxidation state studies in the Black Sea and Norwegian fjords show that major reduction of dissolved Pu(V) occurs [to Pu(III)] in anoxic waters in association with complexation of reduced plutonium with these dissolved and colloidal humics and fulvics. The IAEA-MEL has also been active in developing and applying laboratory radiotracer methods to study rates and pathways of plutonium flux through marine organisms, particularly using the),-emitting tracer, 237Pu. Plutonium concentration factors spanning five orders of magnitude have been observed, with no significant dependence on oxidation state. Almost complete excretion of ingested plutonium by zooplankton makes their defecation an extremely important mechanism in the scavenging of plutonium from surface waters. This phenomenon has been well documentated in many field studies using time-series sediment traps to quantify and characterize elemental flux. Plutonium fluxes in the northwestern Mediterranean have recently been shown to correlate well with mass flux and suggest residence times of 24 and 3.5 years, respectively, for 239' 24°pu and 24'Am in the upper mixed layers, values which are rather longer than those measured previously. The IAEA-MEL has recently studied plutonium distributions in the vicinity of former waste dumpsites in the NE Atlantic Ocean and in the Kara Sea. The results of these surveys provide evidence of radiologically negligible but measurable leakage at the former site and of no leakage whatsoever at the latter. Computer predictions of potential future dispersion of plutonium-containing wastes from the Kara Sea suggest that the maximum possible global collective dose (30 manSv) would be extremely low. Finally, the review notes the increasing analytical contribution to environmental plutonium studies which can be made by mass-spectrometric techniques. At IAEA-MEL, the ETV-ICPMS technique along with low-level radiometric methods is being refined in order to maximize the possibility of using aquatic isotopic signals to characterize and identify nuclear source-terms.

A series of follow-up investigations were performed to produce data for improving the four-indicator carbon selection method that we developed to identify high-potential activated carbons effective for removing specific organic water pollutants. The carbon's pore structure and surface chemistry are dependent on the raw material and the activation process. Coconut carbons have relatively more small pores than large pores; coal and apricot nutshell/walnut shell fruit carbons have the desirable pore structures for removing adsorbates of all sizes. Chemical activation, excessive activation, and/or thermal reactivation enlarge small pores, resulting in reduced phenol number and higher tannic acid number. Activated carbon's phenol, iodine, methylene blue, and tannic acid numbers are convenient indicators of its surface area and pore volume of pore diameters <10, 10-15, 15-28, and >28 A˚, respectively. The phenol number of a carbon is also a good indicator of its surface acidity of oxygen-containing organic functional groups that affect the adsorptive capacity for aromatic and other small polar organics. The tannic acid number is an indicator of carbon's capacity for large, high-molecular-weight natural organic precursors of disinfection by-products in water treatment. The experimental results for removing nitrobenzene, methyl-tert-butyl ether, 4,4-bisphenol, humic acid, and the organic constituents of a biologically treated coking-plant effluent have demonstrated the effectiveness of this capacity-indicator-based method of carbon selection. A comprehensive table of iodine, phenol, methylene blue, and tannic numbers of common activated carbons is a useful database to environmental professionals for selecting few high-potential activated carbons to be evaluated in an efficient water/wastewater treatability study.

Microorganisms synthesise a wide range of surface-active compounds (SAC), generally called biosurfactants. These compounds are mainly classified according to their molecular weight, physico-chemical properties and mode of action. The low-molecular-weight SACs or biosurfactants reduce the surface tension at the air/water interfaces and the interfacial tension at oil/water interfaces, whereas the high-molecular-weight SACs, also called bioemulsifiers, are more effective in stabilising oil-in-water emulsions. Biosurfactants are attracting much interest due to their potential advantages over their synthetic counterparts in many fields spanning environmental, food, biomedical, and other industrial applications. Their large-scale application and production, however, are currently limited by the high cost of production and by limited understanding of their interactions with cells and with the abiotic environment. In this paper, we review the current knowledge and the latest advances in biosurfactant applications and the biotechnological strategies being developed for improving production processes and future potential.

The study of the dense gas flows which occur in many technological applications demands for fluid dynamic simulation tools incorporating complex thermodynamic models that are not usually available in commercial software. Moreover, the software mentioned can be used to study ...

Palm oil esters are high molecular weight esters oil that has been newly synthesized by University Putra Malaysia researchers. It has received a lot of attention for its pharmaceutical and chemical application. Piroxicam is a nonsteroidal anti-inflammatory ...

Microorganisms synthesise a wide range of surface-active compounds (SAC), generally called biosurfactants. These compounds are mainly classified according to their molecular weight, physico-chemical properties and mode of action. The low-molecular-weight SACs or biosurfactants reduce the surface tension at the air/water interfaces and the interfacial tension at oil/water interfaces, whereas the high-molecular-weight SACs, also called bioemulsifiers, are more effective in stabilising oil-in-water emulsions. Biosurfactants are attracting much interest due to their potential advantages over their synthetic counterparts in many fields spanning environmental, food, biomedical, and other industrial applications. Their large-scale application and production, however, are currently limited by the high cost of production and by limited understanding of their interactions with cells and with the abiotic environment. In this paper, we review the current knowledge and the latest advances in biosurfactant applications and the biotechnological strategies being developed for improving production processes and future potential.

The development of techniques in molecular biology has led to their application to microbial ecology. The extraction of DNA, followed by the use of Polymerase Chain Reaction (PCR) to amplify a gene common to all organisms can provide information about microbial community structure, microbial diversity, evolution and taxonomy. Two methods, namely SDS-based extraction method and FastPrepTM method, were evaluated using four different soil samples represent major types of Egyptian soils. The DNA fragment size in the extracts from all soils was &gt;23 kb. The DNA yield from the 4 soils ranged from 18 -52 µg of DNA g-1. The highest DNA yield was observed in Beni-Suef soil rich in organic carbon and nitrogen content and high microbial population. However, Ismalia soil, which is low in organic carbon, nitrogen content and microbial population, had the lowest DNA yield. DNA extracts by SDS based method from all soils did not exhibit high absorbance ratios, due to the presence of absorbing co...

The effect of hot isostatic pressing (HIPing) on as-sintered a-Al 2 O 3 ceramics for total hip arthroplasty (THA) was investigated. The sinterability of these powders and the minimum temperature required to obtain closed porosity have been determined by pressureless sintering in air at temperatures between 1280 and 1460°C for 2 h. Temperatures of 1300 and 1325°C and applied pressures of 150 MPa for 30 min were utilised in the HIP cycles. Densities >98% of the theoretical density (TD) have been obtained after HIPing, and the grain sizes previously obtained during pressureless sintering increased slightly during the HIP treatment. The microstructures before and after HIP treatments were observed by means of scanning electron microscopy (SEM). The fracture toughness was obtained by the indentation fracture technique using a Vickers hardness tester at a load of 10 N with a dwell time of 15 s for all cases. The ceramics obtained at the lowest HIP temperature (1300°C) presented a grain size of 0.62 ± 0.04 lm, hardness of 20.5 ± 0.6 GPa, and fracture toughness of 4.8 ± 0.3 MPa m 1/2. The reported values were higher than those obtained by other authors and were in concordance with international standards that could make these ceramics available as a replacement for metal-on-polyethylene in orthopaedic surgery.

Blends of high density polyethylene (HDPE) with ultra-high molecular weight polyethylene (UHMWPE) were obtained by mixing in a melted state at concentrations ranging from 10 to 30% by weight in an intermeshing co-rotating twin screw extruder (ICTSE). The abrasive resistance of the blends was evaluated according to the DIN53516 standard, and it was observed that the volumetric loss of the blends decreased with increasing concentration of UHMWPE. The mechanical properties of the samples were analyzed in terms of flexural, tensile, and impact strength; in general, the HDPE/UHMWPE blends had a good set of properties, most of which were better than the properties of pure HDPE. Thermal analysis of samples was made by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and no significant difference was observed between the blends and pure HDPE. The morphological analysis conducted by scanning electron microscopy (SEM) showed that the UHMWPE is present in the HDPE matrix as a second phase, but there is a good interface between the two. We found an inverse relationship between the volumetric loss in the abrasive wear of the samples and the product between the tensile strength at yielding and strain at yielding, y ε y , as proposed by Lancaster and Ratner (Sinha and Briscoe, 2009 [1]).

Tyrosinase initiates melanogenesis in a variety of organisms. The nature of melanin formed is modified subsequently by dopachrome isomerase and other melanogenic proteins. Earlier, we reported the partial purification of dopachrome isomerase (decarboxylating) from the hemolymph of Manduca sexta and demonstrated the generation of a new quinone methide intermediate during melanogenesis (Sugumaran, M., and Semensi, V. (1991) J. Biol. Chem. 266, 6073-6078). In this paper, we report the purification of this enzyme to homogeneity and a novel inhibition mechanism for regulation of phenoloxidase activity. The activity of phenoloxidase isolated from M. sexta was markedly inhibited by purified dopachrome isomerase. In turn, phenoloxidase also reciprocated by inhibiting the isomerase activity. Preformed dopaminechrome did not serve as the substrate for the isomerase; but dopaminechrome that generated in situ by phenoloxidase was readily converted to melanin pigment by the phenoloxidase/isomerase mixture. Furthermore, the isomerase, which has a molecular weight of about 40,000 in native state, exhibited retardation during affinity electrophoresis on sodium dodeyl sulfate (SDS)-polyacrylamide gel electrophoresis gel copolymerized with tyrosinase and migrated with a molecular weight of 50,000, indicating complex formation with phenoloxidase. Electrophoresis of pupal cuticu-lar extract on polyacrylamide gel, followed by activity staining revealed the presence of a protein band carrying both phenoloxidase and isomerase activity. Accordingly, a high-molecular-weight melanogenic complex was isolated from the pharate cuticle of M. sexta. The complex catalyzed the generation of melanochrome from dopa, while the free phenoloxidase produced only dopachrome from the same substrate. When the complex was treated with trace amounts of SDS, which inhibited the activity of dopachrome isomerase present in the complex, then only the conversion of dopa to dopachrome was observed. These studies confirm the formation of a melanogenic complex between phenoloxidase and dopachrome isomerase. By forming a complex and regulating each other's activity, these two enzymes seem to control the levels of endogenous quinones.

Four water-soluble high-molecular-weight (1000 kDa) fractions isolated from the roots and stems of Symphytum asperum and Symphytum caucasicum plants, in which the principal component is poly[3-3,4-dihydroxyphenyl)glyceric acid], exhibit significant anticomplement and antioxidant activity. These compounds are capable of decreasing the concentration of reactive oxygen species (ROS), either by directly influencing their production by the polymorphonuclear neutrophils or by scavenging these ROS. The high anticomplement and antioxidant properties suggest that this polymer can be a promising basis for antiinflammatory, vasoprotective, and wound-healing drugs.

The aim of this study was to determine the efficacy of Hylan G-F 20 on experimentally induced osteoarthritic changes in rabbit temporomandibular joint (TMJ). A 3mg/ml concentration of sodium mono iodoacetate (MIA) had been injected into both joints of 24 rabbits to create osteoartrosis. The study group was injected with Hylan G-F 20 in one joint and saline in the contralateral joint as a control (once a week for 3 weeks). Histological changes in articular cartilage, osteochondral junction, chondrocyte appearance and subchondral bone were determined at 4, 6, and 8 weeks. Regarding cartilage, there was a statistically significant difference between the two groups at 4 weeks. Degenerative bony changes to subchondral bone were significantly higher in the controls. No statistical difference was found in the study group at 6 weeks. A positive correlation was found between osteochondral junction and subchondral bone in the study group at 8 weeks. The changes in chondrocyte appearance were ...

Titan, the largest satellite of Saturn, with a dense atmosphere very rich in organics, and many couplings in the various parts of its "geofluid", is a reference for studying prebiotic chemistry on a planetary scale. New data have been obtained from experiments simulating this organic chemistry (gas and aerosol phases), within the right ranges of temperature and a careful avoiding of any chemical contamination. They show a very good agreement with the observational data, demonstrating for the first time the formation of all the organic species already detected in Titan atmosphere including, at last, CdNz, together with many other species not yet detected in Titan. This strongly suggests the presence of more complex organics in Titan's atmosphere and surface, including high molecular weight polyynes and cyanopolyynes. The NASA-ESA Cassini-Huygens mission has been successfully launched in October 1997. The Cassini spacecraft will reach the Saturn system in 2004 and become an orbiter around Saturn, while the Huygens probe will penetrate into Titan's atmosphere. In situ measurements, in particular from Huygens GC-MS and ACP instruments, will provide a detailed analysis of the organics present in the air, aerosols, and surface. This very ambitious mission should yield much information of crucial importance for our knowledge of the complexity of Titan's chemistry, and, more generally for the field of exobiology. 01999 COSPAR. Published by Elsevier Science Ltd.

Poly(vinyl butyral) (PVB)/surfactant with high molecular weight (Pluronic F127) blend hollow fiber membranes were prepared via thermally induced phase separation (TIPS) from PVB/Pluronic F127/diluent (PEG200) system. The phase diagram of PVB/PEG200 system was obtained and the addition of Pluronic F127 to this system led to the decrease of the cloud point. In order to know the kinetic property in the

Anoxic Membrane bioreactor Carbon substrate a b s t r a c t The influence of carbon substrate chemistry on membrane bioreactor (MBR) fouling in anoxic conditions has been evaluated. The use of a weak carboxylic acid (acetic acid) resulted in the production of large open-floc structures (up to 508 mm) that were susceptible to breakage. Primary particles (d 10 and d 20 particle sizes, 5.571.3 and 15.378.2 mm, respectively) and macromolecular soluble microbial products (SMPs) were generated, directly impacting on membrane fouling. The use of a primary alcohol (ethanol), on the other hand, encouraged the growth of flocs similar to activated sludge. These flocs produced low concentrations of primary particles (d 10 and d 20 particle sizes, 120.6736.1 and 185.2762.7 mm, respectively) and high-molecular-weight SMP, and the particles had sufficient mechanical integrity to withstand shear. Consequently, the use of ethanol resulted in sufficient suppression of fouling to extend the filtration time by a factor of three.

The objective of the study is to design Diclofenac sodium SR tablets employing a combination of HPMC K 4M, (hydrophilic polymer), ethyl cellulose (lipophilic polymer) and Sodium alginate (hydrophobic polymer) for better controlled release. Diclofenac SR tablet formulation was optimized by 3 2factorial design. Diclofenac SR tablets were formulated employing the selected combinations of HPMC K4M (Factor A) Sodium alginate (Factor B) and EC (Factor C) as per 3 2-factorial study and prepared by direct compression method. The SR tablets were evaluated for drug release kinetics and mechanism. For optimization, time for % cumulative drug release was taken as response (Y1), % swelling index taken as response (Y2) and the percent of HPMC as X1, percent of sodium alginate as X2 and percent of EC as X3. The polynomial equation describing the relationship between the response Y1, Y2, Y3 and the variables X1, X2 and X3 based on the observed data was worked out. Diclofenac release from the matrix tablets prepared employing HPMC K4M (Factor A) Sodium alginate (Factor B) and EC (Factor C) as per 3 2 factorial design was slow and spread over a longer period of time up to 10 h. The release depended on the composition of the matrix tablet. Diclofenac release from formulations (F-F8) was slow and spread over 8-10 h. Drug release from these tablets was diffusion controlled. Non fickian diffusion was the drug release mechanism. The optimized SR formulation (F3) prepared to give a slow release of Diclofenac over 10 h with a %CDR 81.88%. Diclofenac sodium release from the optimized SR formulation was diffusion controlled and release was by nonfickian (anomalous) diffusion mechanism. Based on the pharmacokinetics, Diclofenac SR tablets for b.i.d administration should contain a total dose of 100 mg of Diclofenac and the desired release rate (K0) is 10.85 mg/h. The drug release rate of optimized SR tablets formulated was found to be 7.37 mg/h, which is very close to the theoretical desired release rate. Hence the optimized formulation (F3) is considered as the best Diclofenac SR formulation developed.

Aims: To investigate the effect of various single nutrient deficiencies on polyb-hydroxybutyrate (PHB) biosynthesis in a methane-utilizing mixed culture (dominant species Methylocystis sp. GB 25 DSM 7674). Methods and Results: Poly-b-hydroxybutyrate accumulation experiments were performed in 7 and 70 l bioreactors and initiated by potassium, sulfur or iron deficiency. After 24 h the PHB content reached levels of 33AE6%, 32AE6% and 10AE4% respectively. Interestingly a polymer with an ultra-high average-weight molecular weight (M w) of 3AE1 MDa was accumulated under potassium-limited conditions. When sulfur and iron were lacking M w were lower by 20AE6 and 41AE6%. Potassium-deficiency experiments were furthermore characterized by a maximum specific PHB formation rate 0AE08 g g)1 residual biomass (R) h)1 and a yield coefficient of 0AE45 g PHB g)1 CH 4. Conclusions: Biosynthesis of an ultra-high M w PHB in a methane-utilizing mixed culture can be induced by potassium deficiency. Significance and Impact of the Study: This study greatly extends the knowledge in the field of bacterial biopolymer formation with gaseous substrates. The special system used here combines the use of methane a low-cost substrate available from natural and renewable sources with the possibility of employing a mixed-culture in an open system for the synthesis of a high-value product.

Wheat and rye grain storage proteins were extracted with 50% (vjv) propan-I-ol at 60°C, and, following reduction with dithiothreitol (OTT), separated in a new, onestep SOS-PAGE system. This system facilitated the simultaneous separation of all the common high molecular weight (HMW) glutenin subunits (including 2 and 2*), low molecular weight (LMW) B-group glutenin subunits, omega-gliadins and 'E' group glutenin subunits of wheat as well as the high molecular weight rye storage proteins coded by genes on chromosomes IR and 2R. In addition to characterizing wheat cuItivars in terms of high and low molecular weight glutenin protein composition, this system can be used also to characterize wheat rye chromosome translocation and substitution lines involving the group I chromosomes, and to identify substituted triticales in which chromosome 20 of wheat has been substituted for chromosome 2R of rye. This simple technique should be applicable to routine screening oflarge numbers oflincs in breeding programs and to cuItivar identification.

We have used hybridization analysis to detect ancient DNA in wheat seeds collected from three archaeological sites in Europe and the Middle East. One of these samples, carbonized T. spelta dated to the first millennium BC, has yielded PCR products after amplification with primers directed at the leader regions of the HMW (high molecular weight) glutenin alleles. Sequences obtained from these products suggest that the DNA present in the Danebury seeds is chemically damaged, as expected for ancient DNA, and also indicate that it should be possible to study the genetic variability of archaeological wheat by ancient DNA analysis. Finally, we describe a PCR-based system that enables tetraploid and hexaploid wheats to be distinguished.

Time-series stations BATS and HOT Amino acids, neutral sugars and amino sugars were analyzed to investigate the chemical composition and diagenetic processing of suspended particulate organic matter (POM, N100 nm), high-molecular-weight dissolved organic matter (HMW DOM, 1-100 nm) and low-molecular-weight dissolved organic matter (LMW DOM, b1 nm) at the time-series stations near Bermuda (BATS) and Hawaii (HOT). Differences between BATS and HOT were principally related to location-specific biogeochemical processes and water mass ventilation ages. Concentrations of amino acids, neutral sugar and amino sugars in unfiltered seawater sharply declined with depth at both stations, indicating an upper ocean source and rapid turnover of these components. The size distribution of organic matter was heavily skewed to smaller molecular sizes. Depth comparisons showed that larger size classes of organic matter were more efficiently removed than smaller size classes. Carbon-normalized yields of amino acids, neutral sugars and amino sugars decreased rapidly with depth and molecular size. Together these biochemicals accounted for 55% of organic carbon in surface POM but only 2% of the organic carbon in LMW DOM in deep water. Chemical compositions showed distinct differences between organic matter size classes indicating the extent of diagenetic processing increased with decreasing molecular size. These findings are consistent with the size-reactivity continuum model for organic matter in which bioreactivity decreases with decreasing molecular size and diagenetic processes lead to the formation of smaller components that are resistant to biodegradation. The data also provided evidence for a size-composition continuum. Carbon-normalized yields of amino acids, neutral sugars and amino sugars were sensitive indicators of diagenetic alterations. Diagenetic indicators based on amino acid compositions revealed distinct patterns for the North Pacific and Sargasso Sea possibly indicating the influence of varying sources or diagenetic processing.

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Runnability problems caused by suspended bacteria in water using industries, have, in contrast to biofilms, received little attention. We describe here that Pseudoxanthomonas taiwanensis, a wide-spread and abundant bacterium in paper machine water circuits, aggregated dispersions of wood extractives (''pitch'') and resin acid, under conditions prevailing in machine water circuits (10 9 cfu ml -1 , pH 8, 45°C). The aggregates were large enough (up to 50 lm) so that they could be expected to clog wires and felts and to reduce dewatering of the fiber web. The Pseudoxanthomonas bacteria were negatively charged over a pH range of 3.2-10. Cationic polyelectrolytes of the types used as retention aids or fixatives to flocculate ''anionic trash'' in paper machines were effective in flocculating the Pseudoxanthomonas bacteria. The polyelectrolyte most effective for this purpose was of high molecular weight (7-8 9 10 6 g mol -1 ) and low charge density (1 meq g -1 ), whereas polyelectrolytes that effectively zeroed the electrophoretic mobility (i.e., neutralized the negative charge) of the bacterium were less effective in flocculating the bacteria. Based on the results, we concluded that the polyelectrolytes functioning by bridging mechanism, rather than by neutralization of the negative charge, may be useful as tools for reducing harmful deposits resulting from interaction of bacteria with wood extractives in warm water industry.

Zn lactate, 3H20 and dehydrated Zn lactate were used as initiator to polymerize DL-lactide under various conditions. It is shown that the latter does polymerize DL-lactide up to high molecular weight at a slower rate than Sn octoate. Zn lactate being formed when lactic acid is allowed to react with Zn metal, it is believed that the active species in Zn metal initiation is Zn lactate. Comparison was made of the two poly(DL-lactide) initiated with Zn metal and Sn octoate respectively and selected to have almost similar characteristics. It is shown that degradation characteristics of the two polymers are different, especially water uptake and rate of heterogeneous degradation. It is further shown that residual Sn concentrated within the matrix remnants whereas the content in Zn remained constant according to degradation controlled release,

From multilocation trials involving 125 cultivars of wheat of mainly French and European origin four tests-protein content, Pelshenke, modified Zeleny and the mixograph-were used to establish six selection indices. Three of these indices-IW1, IW 2 and IW 3-were calculated in order to evaluate the genetic potentiality of the lines for dough strength as given by the Chopin alveograph. The indices IV1, IV 2 and IV 3 were established to evaluate loaf volume as measured by the French bread-making standard. A quality index IQ was calculated from the allelic effects of the high-molecular-weight (HMW) subunits of glutenin from 195 cultivars assessed by the Chopin alveograph and the Pelshenke test. Comparison of the relative efficiency of each of the six indices to the individual tests revealed the superiority of the indices over one or several technological parameters. The six selection indices and the quality index were compared using 30 very diverse 174 lines. Their ability to retain the good quality lines is discussed in particular.

Traditionally, garlic (Allium sativum) is known to be a significant immune booster. Aged garlic extract (AGE) possesses superior immunomodulatory effects than raw garlic; these effects are attributed to the transformed organosulfur compounds. AGE is also known to contain fructans; the amount of fructans in AGE represents a small fraction (0.22%) of the total fructans in raw garlic. In order to evaluate the biological activity of fructans present in AGE, both high molecular weight (>3.5 kDa; HF) and low molecular weight (<3 kDa; LF) fructans were isolated. The structures of purified HF and LF from AGE determined by 1 H NMR and 13 C NMR spectroscopy revealed that both have (2 ? 1) b-D-fructofuranosyl bonds linked to a terminal glucose at the non-reducing end and b-D-fructofuranosyl branching on its backbone. Biological activity of fructans was assessed by immunostimulatory activity using murine lymphocytes and peritoneal exudate cells (source of macrophages). Both HF and LF displayed mitogenic activity and activation of macrophages including phagocytosis. These activities were comparable to that of known polysaccharide immunomodulators such as zymosan and mannan. This study clearly demonstrates that garlic fructans also contribute to the immunomodulatory properties of AGE, and is the first such study on the biological effects of garlic fructans.

Polymersomes are polymer-based vesicular shells that form upon hydration of amphiphilic block copolymers. These high molecular weight amphiphiles impart physicochemical properties that allow polymersomes to stably encapsulate or integrate a broad range of active molecules. This robustness together with recently described mechanisms for controlled breakdown of degradable polymersomes as well as escape from endolysosomes suggests that polymersomes might be usefully viewed as having structure/property/function relationships somewhere between lipid vesicles and viral capsids.

The contamination of soils and waters by metals all over the world continues to present a serious danger to the environment and human health. The development of innovative metal clean-up technologies remains a challenge as current procedures have many limitations, such as being expensive, disruptive, and only efficient for certain concentrations. With high molecular weight and repetitive functional groups, biopolymers provide excellent chelating material for metals. Chitosan is a well-known and efficient metal chelator, but its practical use is limited due to the relatively high costs of constructing clean-up devices (filters) from chitosan alone. In the current study we attempt to find a more cost-effective solution by investigating a new adsorbent material based on chitosan immobilized on sand, namely, chitosan-coated sand (5% chitosan content). This new material was studied for its copper adsorption capacity at contact times of 2, 4, and 6 h and the equilibrium result was compared with copper adsorption capacities of chitosan and sand alone. Hopefully this concept will lead to an application as a large-scale permeable reactive barrier. Copper recovery from an adsorbent with the possible reuse of the adsorbent material was also evaluated in leaching tests. The equilibrium isotherms for Cu adsorption on chitosan-coated sand were described by the Langmuir model. These preliminary results indicate the possibility of using chitosan-coated sand to build inexpensive large-scale barrier filters for metal removal from moving contaminated groundwater plumes.

The aim of the study was to assess the predictive value of known risk factors of asthma, such as atopy, exposure to pet allergens at home, and tobacco smoking, in predicting the occurrence of occupational respiratory allergy due to high-molecularweight allergens. Methods: A questionnaire study, skin-prick tests (SPTs) for common and occupational allergens, and evaluation of total and-in selected cases-specific IgE, were performed in 357 apprentice bakers before and after a year of vocational training. Results: Mean age of examined subjects was 17.2±0.5 years. The prevalence of newly developed symptoms was 7% for rhinitis, 3.1% for chest symptoms, and 3.6% for skin symptoms. The frequency of at least one positive SPT result changed from 17.9% to 24.4% after the 1st year of vocational training, including SPTs for common allergens-from 16.8% to 22.7%, and for occupational allergens-from 2% to 8%. The proportion of subjects with elevated total IgE level increased from 38.7% to 44.3%. Generally, after a year of vocational training 9.2% of examined subjects presented hypersensitivity to occupational allergens. Logistic regression analysis revealed that positive results of SPTs for common allergens (odds ratio (OR) =4.4; 95% confidence intervals (CI) 1.9, 10.27) and elevated IgE level (OR=3.6; 95%CI 1.55, 8.57) were significant risk factors of hypersensitivity to occupational allergens. Conclusions: In apprentice bakers hypersensitivity to occupational allergens develops even during vocational training. SPTs for common allergens, performed before apprentices started their vocational training, would enable the identification of subjects at the highest risk of sensitisation to occupational allergens.

Hyaluronic acid (HA) is a high molecular weight biopolysacharide, discovered in 1934, by Karl Meyer and his assistant, John Palmer in the vitreous of bovine eyes. Hyaluronic acid is a naturally occurring biopolymer, which has important biological functions in bacteria and higher animals including humans. It is found in most connective tissues and is particularly concentrated in synovial fluid, the

The agronomical characters of nine high-protein mutant lines of T. aestivum produced by the IAEA were studied along with their mother line Mex22A and four local cultivars. The experiments were carried out under rainfed conditions in 1990 and 1991 in southern Syria. Statistical analysis revealed significant differences among the lines in all characters. Genotype by environment interaction was significant for all characters except for N yield. There was a negative correlation between grain nitrogen concentration (GNC) and yield. However, two of the check cultivars and seven mutant lines had similar yield to Mex22A with greater GNC. The other two mutant lines, 5074M and E296, were very late in heading and were characterized by low yield with extremely high GNC. Spikes per square meter contributed most to grain yield followed by number of seeds per spike and lastly seed weight. SDS sedimentation test values were negatively correlated with GNC. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE) was used to assay for high molecular weight (HMW) glutenin protein subunits of the grain endosperm. The results showed the presence of HMW glutenin GluD1 subunits 2 + 12 in Mex22A and all IAEA genotypes. Check varieties L92-6, Buhuth 4 and Cham 2 contain the good quality allelic GluDl subunits 5 + 10. Nevertheless, 4 of 9 IAEA mutant lines were characterized by having higher SDS sedimentation values due to the presence of GIu-B1 subunits 17 + 18 when compared to those that had subunits 7 + 8.

We reexamine here the computation of the Casimir force experienced by colloidal par- ticles immersed in a binary mixture, made of two chemically incompatible polymers of high-molecular-weight. Such a force originates from the strong fluctuations of composi- tion near the consolute point Tc, and the fact that one polymer of the mixture prefers to be attracted by colloids (critical adsorption).

In areas of intensive agriculture continuous applications of mineral and organic fertilizers can lead to an accumulation of phosphorus (P) in the soils and progressive saturation of their sorption capacities, increasing the risk of P losses to aquatic ecosystems. The long-term evolution (44 years) of soil P forms has been studied in a factorial experiment combining three soils (sandy, clay and a peaty) with three types of fertilization (no fertilizer, farmyard manure and mineral fertilizer). The P distribution in the calcium P (P Ca), iron P (P Fe), iron + aluminium P (P Fe+Al) forms, and the effect of treatments on P availability (oxalate extractable-P, Mehlich-3-P, Olsen-P, water extractable-P) were determined. Two sorption P indices and the degree of soil saturation were also calculated. Soil P forms were affected by both quantity and quality of P inputs. Farmyard manure caused a more consistent increase in soil P content, affecting the water soluble and labile P forms (Mehlich-3-P and Olsen-P) in particular. Readily assimilable and potentially mobile P forms were positively correlated with the amount of high molecular weight humic fractions, thus stressing the importance of the type of incorporated materials and their evolution in determining soil P behaviour. Soils treated with farmyard manure, and to a lesser extent with mineral fertilizer, exceeded the threshold values of 20 mg kg −1 for Olsen-P and 150 mg kg −1 for Mehlich-3-P, thus evidencing a potential risk of P loss to water bodies. While in absolute terms the more consistent accumulations were observed in clay and peaty soils, the P content of sandy soils is of particular concern, given their lower P sorption capacity and higher degree of saturation. Among the soil P tests, Mehlich-3-P proved to be the best indicator to assess Italian soil conditions for both agronomic and environmental purposes.

Concerns about reduced strength, fatigue resistance, and oxidative stability of highly cross-linked and remelted ultrahigh-molecular-weight polyethylene (UHMWPE) have limited its clinical acceptance for total knee arthroplasty. We hypothesized that a highly cross-linked UHMWPE stabilized with vitamin E would have less oxidation and loss of mechanical properties. We compared the oxidation, in vitro strength, fatigue-crack propagation resistance, and wear of highly cross-linked UHMWPE doped with vitamin E to γ-inert-sterilized direct compressionmolded UHMWPE (control). After accelerated aging, the control material showed elevated oxidation, loss of small-punch mechanical properties, and loss of fatigue-crack propagation resistance. In contrast, the vitamin E-stabilized material had minimal changes and exhibited 73% to 86% reduction in wear for both cruciate-retaining and posterior-stabilized total knee arthroplasty designs. Highly cross-linked vitamin E-stabilized UHMWPE performed well in vitro.