Carbon Aerogels Absorbs Hydrocarbons
Foamy aerogels made of carbon, like their more well studied silicon-based cousins, have innumerable potential uses, from catalysts to sensors. Until now, their synthesis has been expensive or complicated, or has required toxic materials. A team led by Yu Shuhong at the Hefei National Laboratory for Physical Sciences at Micrscale (HFNL), Univ.of Science and Technology of China (USTC) is pursuing their production from biomass. They selected bacterial cellulose (BC) pellicles, a commonly used, inexpensive, nontoxic form of biomass consisting of a tangled network of cellulose nanofibers, as precursor to produce carbon nanofiber aerogels in large-scale. This biomass can easily be produced on an industrial scale through microbial fermentation.
Read more: http://www.laboratoryequipment.com/news/2013/05/carbon-aerogels-absorbs-hydrocarbons
It’s been 17 years since Dolly the sheep was cloned from a mammary cell. And now scientists applied the same technique to make the first embryonic stem cell lines from human skin cells.
Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside of Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking – could humans be cloned in the same way? Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.
Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state. The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the body’s tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.
Nuclear transfer involves inserting a fully developed cell – in Mitalipov’s study, the cells came from the skin of fetuses – into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm. After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor. In Dolly’s case, those cells were allowed to continue developing into an embryo that was then transferred to a ewe to produce a cloned sheep. But Mitalipov says his process with the human cells isn’t designed to generate a human clone, but rather just to create the embryonic stem cells. These could then be manipulated to create heart, nerve or other cells that can repair or treat disease.
“I think this is a really important advance,” says Dieter Egli, an investigator at the New York Stem Cell Foundation. “I have a very high confidence that versions of this technique will work very well; it’s something that the field has been waiting for.” Egli is among the handful of scientists who have been working to perfect the technique with human cells and in 2011, succeeded in producing human stem cells, but with double the number of chromosomes. In 2004, Woo Suk Hwang, a veterinary scientist at Seoul National University, claimed to have succeeded in achieving the feat, but later admitted to faking the data. Instead of generating embryonic stem cell lines via nuclear transfer, Hwang’s group produced the stem cells from days-old embryos, a technique that had already been established by James Thomson at University of Wisconsin in 1998.
- Text by Tobias Capwell
- Sword dating: circa 1605 - 1615
- Culture: Hilt ~ England; blade ~ Germany
- Medium: Steel, gold, silver and wood, blackened, encrusted, and damascened
- Measurements: Length: 114 cm, blade; width: 3.3 cm, blade, above the ricasso; weight: 1.29 kg; length: 130.6 cm, width: 17.3 cm, guard; balance point: 15.6 cm, forward of the guard block
- Inscription: ‘·SANDRINVS · SCACCHVS·’
An exceptionally rare example of Jacobean swordsmithing, this beautiful sword was as much a fashion statement as it was a lethal weapon. Distinct in style from the work of the larger Italian and German sword producing centres, this robust yet refined piece exemplifies English taste, combining a strong construction with delicate gold and silver ornament. Before Sir Richard Wallace acquired this rapier, it was in the collection of William Meyrick, the cousin and heir to the great arms and armour scholar Sir Samuel Rush Meyrick (1786-1848).
In 1861 William Meyrick stated that the hilt and pommel of this sword had been ‘recently dug up at Saffron Walden’ in Essex. The pieces were cleaned and possibly to some extent restored and a ‘suitable blade’ added to reform the fragments into a complete weapon. Though in part restored, this fine rapier remains an important example of the type of sword fashionable at the court of King James I.
A number of features mark this piece out as being English work of a high quality, rather than the product of one of the great Italian or German workshops. The very large pear-shaped pommel is typical of English swords of this period. The rounded qualities of this sword are further emphasised by the oval terminals located on the ends of the cross-guard and forward-guard, and placed centrally on the knuckle-bow and loopguard. The decoration is also distinctively English, the rich silver encrusting being found on a number of comparable English swords, including that of Henry Frederick, Prince of Wales (1594-1612), the son of King James I.
The encrusting on this sword takes the typical form of masks surrounded with feathers and foliage, while lines of silver beads form panels along the bars of the hilt and surrounding surface of the pommel. These panels are filled with very fine gold foliate scrolls. These are false-damascened; the surface is roughened or cross-hatched and covered with gold foil or wire. The style of these scrolls is closely comparable to the decoration found on knives of the period bearing London cutlers’ marks.