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Friday, 9 July 2010

The Cost of Cartilage Health: maintenance better than surgical repair?

Glucosamine and chondroitin are widely taken to help relieve knee pain from osteoarthritis but do they work?

The GAIT Study:

     Double blind
The study, like most good medical studies, was done ‘double blind’, that is neither the patients nor the people administering to them knew which treatment the patient was on.

     MORE cf link below
But when results of the group of patients with moderate to severe pain was analysed the investigators found that the combination of glucosamine and chondroitin sulphate WAS significantly effective for pain relief!
ie. a healthy dynamic life style may be pursued?
(This is true in my case - Add my experience to the study -Chondrosulf alone 400mg x 3 per day.)
The GUIDE finding Both glucosamine sulphate and acetaminophen were more effective in reducing pain than placebo. Patients taking glucosamine sulphate exhibited more relief than patients on acetaminophen.

It was concluded that once-daily 1500 mg oral doses of glucosamine sulphate may be the preferred treatment for knee osteoarthritis.

Note
It must be noted that unlike the GAIT study that was publicly funded the GUIDE study was sponsored by the manufacturers of the glucosamine compound that was used in the trial.


In both the GAIT and GUIDE studies 1500mg of glucosamine daily was used and in the GAIT study 1200mg of chondroitin daily was used. However, some manufacturers suggest that glucosamine and chondroitin sulphate supplements should be taken in two phases, for example -

* A loading phase of a month of increased levels of glucosamine (up to 2250mg) and 1200mg of chondroitin sulphate.

* A maintenance phase of 1500mg of glucosamine and 800mg of chondroitin sulphate.

Other suggestions are that glucosamine and chondroitin sulphate doses should be calculated based on a person’s body weight. One recommendation is 20mg of glucosamine for every 1kg of body weight, whilst another suggestion is as follows:

* If body weight is less than 54.5kg take 1,000mg glucosamine and 800mg chondroitin sulphate.
*
* If body weight is between 54.5 and 91kg take 1,500mg glucosamine and 1,200 mg chondroitin sulphate.
*
* If body weight is more than 91kg take 2,000mg glucosamine and 1,600mg chondroitin sulphate.
(sounds reasonably logical start point from a materials engineering stand point) Are these ploys by supplement companies to sell more of their product or is there a scientific basis for these recommendations? Well, at present the evidence for doses and schedules is fairly sparse and that is one of the reasons why daily doses of 1500mg of glucosamine and 1200mg of chondroitin sulphate are common recommendations.

What about the source of these products-QC-AC-TQM?

Chondroitin sulphate is usually produced from cow (bovine) cartilage but can be produced from pig (porcine), chicken and even shark cartilage. Glucosamine on the other hand is derived from shellfish, usually shrimp, lobster or crab shells.


An important and informative discussion followed cf link
en référence à :
"Other factors   Chondroitin sulphate production in the body can be hindered if there is a deficiency of some key vitamins and minerals, in particular manganese, vitamin C and vitamin A. As participants in the GAIT study didn’t appear to undergo a dietary analysis prior to the start of the trial it is possible that some individuals may have had deficiencies in these key substances."
- Cartilage Health - Glucosamine and Chondroitin Supplement (afficher sur Google Sidewiki)

COMMENT:

Although I have no information on the cost of "wide-spread full life-cycle cost of surgery, It would appear obvious to an industrial R&D person such as I that the low risk relatively easy to extend chemical route is the road to take and ought to be introduced before serious pain results. In my case knee pain was reaching the handicapping stage whereby X-Rat readily detected near absence of cartilage on one side of th knee joint. The chemical supplement has been working well for several years and I am sorry not to have discovered in a simple X-Ray check-up! Not only has knee pain practically totally disappeared improvement in back-pain and disc slip has also greatly improved by my Chondroitin suppliment intake

Materials Views_2010-05-28 reports superior hyper-duplex corrosion resistant stainless steel

Materials Views_2010-05-28 reports superior hyper-duplex corrosion resistance. "The Influence of microstructure on the corrosion resistance of a newly developed hyperduplex stainless steel has been studied by a team of Brazilian  Metallurgists; S. S. M. Tavares, J. M. Pardal, A. Loureiro , E. Ponzio,  J. A. de Souza from the Universidade Federal Fluminense -  (Brazil)"

"Hyperduplex UNS S32707 is a newly developed austenitic-ferritic (dual phase or duplex) stainless steel. The steel contains about 27%Cr, 7%Ni, 4.5%Mo, and 0.4%N, which results in a pitting resistance equivalent factor (PRE) equal to 49. In this study, the pitting corrosion resistance of this new grade of stainless steel was investigated by varying the microstructure using different thermal processes. The critical pitting temperature measurement and cyclic polarization tests confirm the high corrosion resistance of the hyperduplex steel in the solution treated condition. However, deleterious phases form easily during thermal processing and cause a drastic decrease in the corrosion resistance.

Jounal, Authors and ABSTRACT

Materials Views Summary

Materials Views' Martin Grolms gives the reader some some of the essentials:eg.
For ranking the pitting resistance equivalent (PRE) number is used. PRE is based on the chemical composition of the steel and can be calculated as following:

PRE=%Cr+3.3(%Mo+%W)+16(%N)).

Increasing some of the parameters, like in this case, the amounts of Cr and N, leads to the development of stainless steel with ultrahigh corrosion resistance - hyperduplex steel. It contains about 27%Cr, 7%Ni, 4.5%Mo, and 0.4%N, so that PRE is equal to 49.

Pitting potential at a fixed temperature and critical pitting temperature (CPT) both increase with the PRE value. For hyperduplex steel CPT values above 90 have been reported. However, precipitation of tertiary phases such as sigma (δ), chi (χ), and Cr2N often decreases the CPT.

At the Brazilian Fluminense Federal University (UFF) investigations were conducted to get a deeper insight into the microstructure and corrosion properties of the new hyperduplex stainless steel.

Experimental:
A tube of steel, with a diameter of 12.5 mm and thickness of 2 mm, was purchased under the solution treated condition. Small pieces of this tube were cut for the study.

One of the specimens represented the original hyperduplex tube, while the other ones were produced by six different thermal procedures.

Results-Microstructure:
Afterwards some specimens had unequal austenite/ferrite proportions, and other were δ-phase precipitated.

The experimental procedure and results are further summarised in Materials views

Findings:
The corrosion resistance of hyperduplex stainless steel is higher than the other austenitic–ferritic steels, since a CPT higher than 92°C was obtained. The Critical PRE values are approx. 45–55ºC for solution treated duplex steels and 80–90ºC for superduplex steels.

Applications:
“The first application of hyperduplex stainless steels seems to be as heat exchange tubes used in the petroleum platforms in Brazil”, says Sérgio S.M. Tavares from UFF. “The material has mechanical and corrosion resistance superior to superduplex steels, which makes it very attractive in the off-shore equipments. High Cr and Mo content makes it more susceptible to embrittlement phenomena associated to intermetallic precipitation. The challenge lies in the development of reliable welding procedures for the hyperduplex steel”.

“The first application of hyperduplex stainless steels seems to be as heat exchange tubes used in the petroleum platforms in Brazil”, says Sérgio S.M. Tavares from UFF. “The material has mechanical and corrosion resistance superior to superduplex steels, which makes it very attractive in the off-shore equipments. High Cr and Mo content makes it more susceptible to embrittlement phenomena associated to intermetallic precipitation. The challenge lies in the development of reliable welding procedures for the hyperduplex steel”.

References:
MaterialsViews with enlarged size micro-image.
Wiley Interscience

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It's not HSLA-Bainite"Nanostructured Steels"-Green Light by Irvine-based Materials Science Co-MMFX Tech Corp - Corrosion and Toughness Themes

Other References
Duplex Stainless Steels (Conference proceedings / American Society for Metals)Duplex Stainless Steels (Conference proceedings / American Society for Metals)

High Purity Cr sources for Superalloys

Energy for th Future:Phil.Trans.A-Vol. 365, N° 1853 / April 15, 2007, curtesy The Royal Soc. London

Engineered foams and porous materials: Phil Trans A. Vol 364, N° 1838 / 06 curtesy_The R Soc. Lond