A Review of Lubrication Conditions for Wear Simulation in Artificial Hip Replacements

It is essential to evaluate the wear behavior of joint replacement materials and designs. While synovial fluid is the biological joint lubricant, it is present in too small quantities to use for wear simulations. A variety of lubricants have been used, such as water, saline solutions, synovial fluid components (hyaluronic acid, lubricin, and phospholipids), serum, and custom-made lubricants. We review studies from our Loma Linda University Medical Center lab and other labs using metal-on-polyethylene, exploring the benefits and deficiencies of these pseudo-synovial fluids. Serum is used extensively as the lubricant because its results most closely match clinical results with polyethylene bearings. We summarize laboratory experiments that have explored the effects of serum with differences in proteins (concentration, type, and ratio), volume, viscosity, temperature, and additives and their wear response. Protein precipitates seem to protect the implants from wear. The properties of current lubricants, in particular the roles of proteins, are the current focus in the search for an ideal joint analogue fluid.

     

Soluble Hydrocolloids Enable Fat Reduction in Process Cheese Spreads

Aqueous dispersions of soluble hydrocolloids replaced lipids in process cheese spreads. About 40% and 50% fat reduction was obtained relative to a control cheese spread containing 25% fat by increasing moisture to 62% and 68%, respectively, and eliminating a portion of fat from the formulation. Xanthan, λ-carrageenan, three types of high-methoxyl pectin, propylene glycol alginate, low-viscosity guar and Zooglan 115 gums were added to process cheese spreads at 0.18% to 4.1% wet basis. Spreads with 2.2%λ -carrageenan, 1.7% to 2.2% pectin or 1.7% low-viscosity guar had textures consistent with a high-fat cheese control. Above these gum levels, cheese spread firmness (by Instron measure) increased while melt decreased. A 15% fat, 62% moisture cheese spread with 1.7% pectin was most like the control. In sensory studies it was less preferred than a control spread (25% fat, 48% moisture) due partially to less flavor.     

Chemical Composition of Distillers' Dried Grains with Solubles (DDGS) from Soft White Wheat, Hard Red Wheat and Corn

The chemical composition of distillers' dried grains with solubles (DDGS) produced from two varieties of soft white wheat, a blend of hard red wheats, and corn was determined. On the average, the concentration of protein increased 2.4–3.1 times, crude fiber 2.6–3.8 times, and lipid 1.4–2.4 times. The carbohydrate decreased by 30–50% in DDGS compared to the corresponding starting grain. The ash in DDGS was 3.8–7.8 times that of the original grain. Many of the differences (p < 0.05) in the concentration of lipid, protein, and crude fiber among the starting grains were also present in the DDGS products.     

THE GRADING OF LOW-ESTER PECTIN FOR USE IN DESSERT GELS

Dessert gels made from a commercially available low-ester pectin were examined for firmness with a modified Sunkist Exchange Ridgelimeter and for breaking pressure using a Marine Colloids Gel Tester. Data are presented to show the effect of temperature, pH, pectin concentration, cooking time and calcium level on these two quality characteristics. Based on the data obtained a suggested grading procedure in terms of low-ester firmness (F) and low-ester strength (S) was developed.     

A STUDY OF ALTERNATION OF NORMAL AND DISTORTED VISION.

SS RESPONDED IN ACCORDANCE WITH THE APPARENT DISTANCE OF A TARGET, ALTERNATING BETWEEN NORMAL VISION AND MINIFICATION. CHANGES IN PERFORMANCE INDUCED BY CHANGING THE VISUAL CONDITION WERE AS MARKED AFTER REPEATED EXPOSURES AS INITIALLY, PROVIDED THAT NO CURRENT FEEDBACK WAS SUPPLIED. THIS WAS TAKEN AS LACK OF SUPPORT FOR TAYLOR'S PREDICTION: THAT EFFECTS AND AFTEREFFECTS SHOULD DECLINE WITH ALTERNATION OF VISUAL CONDITIONS. CONTRARY TO THE DIFFERENTIAL CONDITIONING MODEL OF ADAPTATION, THEIR ELIMINATION APPARENTLY CONTINUES TO DEPEND ON RESPONSE-PRODUCED FEEDBACK. (FRENCH SUMMARY) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of marine aerosol particles in coastal zones using satellite imagery

Regions of brightness variations are common in visible and near-infrared satellites images from clear coastal regions. The variations have been hypothesized to be caused by aerosol particles in the marine boundary layer. The hypothesis was tested using in situ particle measurements collected near the time of satellite overpasses. Boundary-layer particle concentrations related to the brightness variations: high concentrations existed in bright regions and vice versa. This result indicates that, in regions over the ocean free of clouds, sunglint and whitecaps, the visible and near-infrared sensors aboard certain orbiting meteorological satellites can detect variations in the concentrations of haze particles in the marine boundary layer.     

Degradation of δ-alumina fibre during extrusionof Al-20Si-X powder metallurgical composite

Powder metallurgical composites consisting of atomized Al-Si-X powder and Saffil δ-alumina fibres were previously consolidated by hot extrusion using various reduction ratios. The microstructure at the fibre-matrix interface, as well as the fibre chemistry of some of these composites, were investigated. The results point towards a relation between mechanical fibre damage during extrusion, extrusion reduction ratio, fibre volume fraction and matrix solute enrichment of fibres. Arguments are forwarded to support the view that the fibres’ specific internal texture (porosity/surface), their chemical surface activity at the temperature of extrusion and mechanical fragmentation, allowed the rapidity of the chemical interaction. The mechanical fibre damage partly arose from abrasion by equally hard silicon particles. The implications are that the strength and reinforcing potential of fibres in composites like these can be greatly reduced. This revised version was published online in November 2006 with corrections to the Cover Date.     

Characteristics of Israeli Citrus Peel and Citrus Juice

Data on the composition of Israeli orange juice, grapefruit juice, orange peel and grapefruit peel were analyzed. Significant differences were found mainly between the juice and peel in the content of isocitric acid, ash, minerals, total pectin, total flavonoids, chlorides, phosphates, chloramine-T number and arginine. The significance of these findings in detecting juice adulteration with peel extract solids is discussed. The chemical and amino acids characteristics of the citrus products analyzed may be used to establish guidelines required for detecting citrus juice adulteration.     

Effects of Sodium Tripolyphosphate on Physical and Sensory Properties of Beef and Pork Roasts

Six paired beef round and pork loin roasts were used to determine the effects of sodium tripolyphosphate (STPP) on fresh and reheated roasts. Roasts were pumped 10% of their weight with distilled water (control) or with distilled water containing 4.75% STPP. Roasts were cooked to internal temperatures of 70°C (beef) or 75°C (pork) and evaluated after 0, 1 or 3 days (roasts were reheated to cooked temperatures). This study indicates that phosphate in pork and beef roasts allowed them to be reheated after 1 and 3 days of refrigeration with minimal losses of juiciness, tenderness or flavor intensity, Phosphate injection reduced warmed-over flavor in reheated pork roasts but was not successful in decreasing the incidence of warmedover flavors in reheated beef roasts.     

Effects of Internal Temperature and Thickness on Palatability of Pork Loin Chops

Three thicknesses (2.54, 1.90 and 1.27 cm) of pork chops were cutl alternately from 20 paired loins of similar quality. Chops were cooked on Farberware grills or in a convection oven to internal temperatures of 60, 70 and 80°C for sensory and objective evaluations. Juiciness, percent moisture and tenderness decreased and cooking losses increased (P < 0.05) as temperature increased for both cooking methods. Pork flavor intensity increased in oven- prepared chops, while no change was observed in grilled chops at each level of increased temperature. Thickness had no effect (P > 0.05) on tenderness, juiciness or total cooking loss of oven-prepared or grilled chops. The thickest chops received the highest (P < 0.05) pork flavor scores.