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Adherent cell lines will grow in vitro until they have covered the surface area available or the medium is depleted of nutrients. At this point the cell lines should be sub-cultured in order to prevent the culture dying. To subculture the cells they need to be brought into suspension. The degree of adhesion varies from cell line to cell line but in the majority of cases proteases, e.g. trypsin, are used to release the cells from the flask. However, this may not be appropriate for some lines where exposure to proteases is harmful or where the enzymes used remove membrane markers/receptors of interest. In these cases cells should be brought into suspension into a small volume of medium mechanically with the aid of cell scrapers.

Schematic diagram of "Subculture of Adherent Cell Lines"

Materials

• Media– pre-warmed to 37oC (refer to the ECACC Cell Line Data Sheet for the correct medium)
• 70% ethanol in water
• PBS without Ca2+/Mg2+
• 0.25% trypsin/EDTA in HBSS, without Ca2+/Mg2+
• Trypsin
• ELISA Plate
• Soybean trypsin Inhibitor

Equipment

• Personal protective equipment (sterile gloves, Laboratory coat, safety visor)
• Waterbath set to appropriate temperature
• Microbiological safety cabinet at appropriate containment level
• CO2 incubator
• Pre-labeled flasks
• Cell Culture Plates(96-well plate)
• Marker Pen
• Pipettes
• Ampule Rack
• Tissue

Procedure

1. View cultures using an inverted microscope to assess the degree of confluency and confirm the absence of bacterial and fungal contaminants.
2. Remove spent medium.
3. Wash the cell monolayer with PBS without Ca2+/Mg2+ using a volume equivalent to half the volume of culture medium. Repeat this wash step if the cells are known to adhere strongly.
4. Pipette trypsin/EDTA onto the washed cell monolayer using 1ml per 25cm2 of surface area. Rotate flask to cover the monolayer with trypsin. Decant the excess trypsin.
5. Return flask to the incubator and leave for 2-10 minutes.
6. Examine the cells using an inverted microscope to ensure that all the cells are detached and floating. The side of the flasks may be gently tapped to release any remaining attached cells.
7. Resuspend the cells in a small volume of fresh serum-containing medium to inactivate the trypsin. Remove 100-200uL and perform a cell count.
8. Transfer the required number of cells to a new labeled flask containing pre-warmed medium.
9. Incubate as appropriate for the cell line.
10. Repeat this process as demanded by the growth characteristics of the cell line.

Key Points

1. Some cultures whilst growing as attached lines adhere only lightly to the flask and 96 well plate, thus it is important to ensure that the culture medium is retained and the flasks are handled with care to prevent the cells detaching prematurely.
2. Although most cells will detach in the presence of trypsin alone the EDTA is added to enhance the activity of the enzyme.
3. Trypsin is inactivated in the presence of serum. Therefore, it is essential to remove all traces of serum from the culture medium by washing the monolayer of cells with PBS without Ca2+/Mg2+.
4. Cells should only be exposed to trypsin/EDTA long enough to detach cells. Prolonged exposure could damage surface receptors.
5. Trypsin should be neutralized with serum prior to seeding cells into new flasks otherwise cells will not attach.
6. Trypsin may also be neutralized by the addition of soybean trypsin inhibitor, where an equal volume of inhibitor at a concentration of 1mg/ml is added to the trypsinised cells. The cells are then centrifuged, resuspended in fresh culture medium and counted as above. This is especially necessary for serum-free cell culture plates.
7. If a CO2 incubator is not available gas the flasks for 1-2min with 5% CO2 in 95% air filtered through a 0.25m filter.

Source: Sigmaaldrich

Many cultures obtained from a culture collection, such as ECACC, will arrive frozen and in order to use them the cells must be thawed and put into culture. It is vital to thaw cells correctly in order to maintain the viability of the culture and enable the culture to recover more quickly. Some cryoprotectants, such as DMSO, are toxic above 4oC therefore it is essential that cultures are thawed quickly and diluted in culture medium to minimize the toxic effects.

A schematic diagram of "Resuscitation of Frozen Cell Lines"

Materials

• Media– pre-warmed to the appropriate temperature (refer to the ECACC Cell Line Data Sheet for the correct medium and size of flask to resuscitation into.)
• 70% ethanol in water
• DMSO

Equipment

• Personal protective equipment (sterile gloves, Laboratory coat, safety visor)
• Waterbath set to appropriate temperature
• Glass Bottom Dishes
• Microbiological safety cabinet at appropriate containment level
• CO2 incubator
• Pre labeled flasks
• Marker Pen
• Pipettes
• ELISA plates
• Ampule Rack
• Tissue

Procedure

1. Read Technical data sheet to establish specific requirements for your cell line.
2. Prepare the flasks as appropriate (information on technical data sheet). Label with cell line name, passage number and date.
3. Collect ampule of cells from liquid nitrogen storage wearing appropriate protective equipment and transfer to laboratory in a sealed container.
4. Still wearing protective clothing, remove ampule from container and place in a waterbath at an appropriate temperature for your cell line e.g. 37oC for mammalian cells. Submerge only the lower half of the ampule. Allow to thaw until a small amount of ice remains in the vial - usually 1-2 minutes. Transfer to class II safety cabinet.
5. Wipe the outside of the ampule with a tissue moistened (not excessively) with 70% alcohol hold tissue over ampule to loosen lid.
6. Slowly, dropwise, pipette cells into pre-warmed growth medium to dilute out the DMSO (cell culture flasks prepared in Step 2).
7. Incubate at the appropriate temperature for species and appropriate concentration of CO2 in atmosphere.
8. Examine cells microscopically (phase contrast) after 24 hours and sub-culture as necessary.

Key Points

1. Most text books recommend washing the thawed cells in media to remove the cryoprotectant. This is only necessary if the cryoprotectant is known to have an adverse effect on the cells. In such cases the cells should be washed in media before being added to their final culture flasks. See Protocol 7 for further details.
2. Do not use an incubator to thaw cell cultures since the rate of thawing achieved is too slow resulting in a loss of viability.
3. If a CO2 incubator is not available gas the flasks for 1-2 minutes with 5% CO2 in 95% air filtered through a 0.25m filter.
4. For some cultures it is necessary to subculture before confluence is reached in order to maintain their characteristics e.g. the contact inhibition of NIH 3T3 (Prod. No. 93061524) cells is lost if they are allowed to reach confluence repeatedly.

Scouce: ECACC Handbook Protocol 2

Aim To ensure all cell culture procedures are performed to a standard that will prevent contamination from bacteria, fungi and mycoplasma and cross contamination with other cell lines.

Materials

• Chloros / Presept solution (2.5g/l)
• 1% formaldehyde based disinfectant e.g.Virkon,Tegador
• 70% ethanol in water (Prod. No. R8382)

Equipment

• Personal protective equipment (sterile gloves, laboratory coat, safety visor)
• Microbiological safety cabinet at appropriate containment level
• Cell Culture Plates(6 well plate, 24 well plate, 96 well plate)

Procedure

1. Sanitize the cabinet using 70% ethanol before commencing work.
2. Sanitize gloves by washing them in 70% ethanol and allowing to air dry for 30 seconds before commencing work.
3. Put all materials and equipment into the cabinet prior to starting work after sanitizing the exterior surfaces with 70% ethanol.
4. Whilst working do not contaminate gloves by touching anything outside the cabinet (especially face and hair). If gloves become contaminated re-sanitize with 70% ethanol as above before proceeding.
5. Discard gloves after handling contaminated cultures and at the end of all cell culture procedures.
6. Equipment in the cabinet or that which will be taken into the cabinet during cell culture procedures (media bottles, pipette tip boxes, pipette aids, cell culture plates) should be wiped with tissue soaked with 70% ethanol prior to use.
7. Movement within and immediately outside the cabinet must not be rapid. Slow movement will allow the air within the cabinet to circulate properly.
8. Speech, sneezing and coughing must be directed away from the cabinet so as not to disrupt the airflow.
9. After completing work disinfect all equipment and material before removing from the cabinet. Spray the work surfaces inside the cabinet with 70% ethanol and wipe dry with tissue. Dispose of tissue by autoclaving.
10. Cell culture discard in chloros (10,000) ppm must be kept in the cabinet for a minimum of two hours (preferably overnight) prior to discarding down the sink with copious amounts of water.
11. Periodically clean the cabinet surfaces with a disinfectant such as Presept,Tegador or Virkon or fumigate the cabinet according to the manufacturers instructions. However you must ensure that it is safe to fumigate your own laboratory environment due to the generation of gaseous formaldehyde, consult your on-site Health and Safety Advisor.

Source: Sigma-Aldrich

In this article we explain how to choose the right bracelet. Your bracelet could be made in silver or gold, it could be a simple bracelet or be studded with stones and diamonds. Make sure that you know how to evaluate a good bracelet.

Step One

Basic Design: The first thing that you should consider is the basic design of the bracelet. The design should be streamlined without sharp or pointed edges. Sharp edges can not only injure delicate skin, but also get bent or dented easily. The type of mounting used for the diamonds and gemstones in your bracelet will depend on the design. Prongs used to mount gems need to be sturdy and strong. If the gemstones in your bracelet are mounted with thin needle-like prongs, the prongs can get caught in pockets and other places. This causes the prongs to gradually open up, this ofcourse loosens the gemstones which can then drop off. The design dimensions for your bracelet should take the metal weight into consideration. A wide width with low gold or silver weight, will mean that the metal is too thin. This can cause your bracelet to lose shape and get damaged.

Step Two

Metal Weight: The metal weight of the bracelet is another important thing to be checked. Good mounting of the gemstones or diamonds in your bracelet will need sufficient gold or silver weight. There can be no standard weight suitable for all bracelets, much will depend on the design, the number of gems and diamonds, the length and width of the bracelet etc. Looks can be deceptive so pay special attention to the weight of your bracelet. In general you can be sure that, ladies bracelets with a metal weight that is less than 10 grams will not be durable and sturdy. Your jeweller might tell you that, healthy metal weight will make your bracelet appear clumsy and bulky. Stop believing this nonsense, the truth is that the design needs to ensure that the bracelet does not appear bulky. The design for your bracelet should have good metal thickness, this will not be visible from the front of the bracelet. Compromising on the gold or silver weight of your bracelet would also mean that, the links that connect the segments of the bracelet will be weak. This can cause the bracelet to snap, it could then easily fall off your wrist and get lost. So remember that, good metal weight is essential for gold or silver bracelets.

Step Three

Gemstone Options:You should also be given a wide range of gemstone options to select for your bracelet. Many jewellers use whatever few gemstones they have and put a bracelet together. This does not work to your advantage as you are restricted in your choice. You could choose the gemstones in your bracelet based on color, type, birthstone or traditional beliefs. For example, a mother's bracelet could include the birthstone of the mother and all her children. Such family birthstone bracelets can be made only if a wide choice of gems is available. There is ofcourse the issue of budget that you have at your disposal. You might see a gorgeous sapphire bracelet but, the sapphires could drive the bracelet out of your budget. You should be allowed to choose the same bracelet with cheaper gems like, blue topaz, iolite or probably cheaper sapphires. A jeweller with limited access to gems and production facilities will restrict your choice too. There is also the issue of conditions in which your bracelet would be worn. For example, an emerald bracelet needs special care when wearing and storing, this is because of the nature of emeralds. You might pefer the same bracelet design with green tourmaline instead of emeralds. Your jeweller will need to satisfy your requirements and not the other way round.

Step Four

Choose The Metal: The metal for your bracelet will be a component of the price tag, a gold bracelet would add a substantial amount to the price tag. You should therefore have the option to choose gold or silver for your bracelet. Most jewellers are very eager to sell gold bracelets, but will either ignore you are provide you with second grade service if you talk about a silver bracelet. This is sad but true, so look for a jeweller who is willing to make a good quality silver bracelet for you if that is what you want. It is often said and rightly that, a good quality silver bracelet is better than a delicate and light weight gold bracelet. When you choose your silver bracelet remember that, no compromises regarding gemstone choice or craftsmanship need be made. For gold bracelets, you should have the option to select a 14k or 18k bracelet and also choose the gold color. If you are looking for a white gold bracelet, there is no reason why you should be happy with a yellow gold aquamarine bracelet. Jewellers make gold bracelets with low weight, this is done to allow lower price tags. They really don't care what problems these light weight junk will cause you after the payment has been made.

Step Five

Good Craftsmanship: Insist on good craftsmanship for your bracelet, this should be the case for gold or silver bracelets. Bad craftsmanship could also mean loose gemstones and badly connected links. It is true that mass produced bracelets cannot be given individual attention. This is the reason why a custom bracelet could be best for you. Good craftsmanship is essential for ladies and men's bracelets, make sure that your bracelet is well crafted. Good craftsmanship provides more than just good appearance for your bracelet, this will clearly work to your advantage in the longterm.

Tiffany Mall is cheap tiffany jewelry online store. We have added about 200 Tiffany Jewelry to the site for our customers. Our mission is to provide the best products (sunch as tiffany bracelets) and service to our customers at the lowest prices possible.

I won an auction for a Tiffany bracelet. But before I even bid, I emailed the seller, asking her if this was authentic, even though in the auction details, she stated that it was.

I know there are A LOT of fakes on eBay, but with 100% feedback from 65 people, I thought they were legitimate. I was wrong.

Anyone who's bought/received Tiffany's jewelry from Tiffany's website KNOWS what to expect in the mail. A heavy polishing cloth/carrying case, a turquoise box, and an authentic piece.

I knew IMMEDIATELY when I opened the box that I had been duped. The lime green box had Tiffany & Co. smudged on top. The polishing cloth/carrying case was hollow inside and made of some hardened material. Again, the logo was printed and smudged. To make it worse, the bracelet didn't even say Tiffany & Co.

I contacted the seller, and she denied it was a fake. Owning several rings and bracelets, I know what tiffany jewelry is supposed to look like. She refused a refund, and I was out $80.00!!!

Apparently this seller bought a fake box (lime green!)and cleaning cloth/carrying case off of eBay - and was passing off a fake bracelet as authentic.

I contacted PayPal - they asked that I return the package to her so that my refund was processed. I did exactly that, and added delivery confirmation to "cover myself". She then tells PayPal the package was empty, and no ring was shipped back. I contacted eBay, and thought they would cancel the auction, absolving me from responsibility. I was wrong again. I had already paid and received the bracelet so I was basically stuck with a fake bracelet and nothing else.

I was out $80.00 PLUS $4.00 to ship the item back. The seller received the bracelet & my money.

Be sure to read all of the fine print of a auction. She stated at the bottom of the auction that the buyer had to pay for shipping it back!! I buy something I think is authentic, and when I find out it's not, I'm out the return shipping charges!!!

As Buyer, you must protect yourself.

While there are some people selling their Tiffany & Co. jewelry (tiffany necklaces, tiffany pendants, tiffany bracelets, tiffany earrings, tiffany rings), be careful. You could end up with a fake peice like I did, and have to pay to ship it back, and STILL not get refunded.

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It was Tiffany & Co. that introduced the engagement ring as we know it today. The celebrated six-prong “Tiffany® Setting” lifts the diamond above the band and into the light. The result is a ring whose beauty has never been equaled.

In 1848 the New York City newspapers dubbed Charles Lewis Tiffany, “The King of Diamonds.” And with good reason. The quality of Tiffany diamonds was then, and remains, exemplary. In the spring of 1887, Tiffany shocked the world by purchasing the French Crown Jewels. From this time on, Tiffany became the world’s authority on the finest diamonds.

Soon Tiffany designers were creating brilliance of their own. From the glittering 1890s on, timeless Tiffany designs graced women from the finest families: the Astors, the Vanderbilts, the Morgans. Celebrities from the theater, sports, and ultimately European royalty and Hollywood stars began to prize Tiffany diamond designs.

Around the world, museums treasure the Tiffany design aesthetic, from the Art Nouveau period to Art Deco to today’s modern classics. Year in, year out, the passion for Tiffany diamonds is clearly demonstrated in the world’s auction houses.

Today, the world-famous 128.54-carat Tiffany Diamond is on permanent display in the New York flagship store—proof positive of Tiffany’s diamond legacy.

List of Tiffany & Co. products:

• Tiffany Necklace
• Tiffany Pendant
• Tiffany Bracelet
• Tiffany Earrings
• Tiffany Ring
• Tiffany Pocket Mirror

But nowhere is a Tiffany diamond more beautiful or more treasured than in its place of honor, on the hand of a woman.

You can get more infomation from www.tiffany.com.

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