Phenyllithium or lithobenzene is an organometallic agent with the empirical formula C6H5Li. Crystalline phenyllithium is colorless; however, solutions of phenyllithium are various shades of brown or red depending on the solvent. It is a highly air and moisture sensitive compound, that could be easily decomposed by any protic solvent.
In this case it was a byproduct of a synthesis of an organophosphorous compound and it was only present in a LOW concentration, therefore it was safe to decompose it by simply adding cold water. It’s important to note that it could be dangerous to decompose organometallic compounds by simply adding water. Also, in this case, the highly toxic BENZENE was the product of this reaction, what should be handled with care.
Midwives and nurses sometimes came under suspicion because of their specialised knowledge and success - or failure - in treating those who were sick. These healing roles were traditionally taken on by women who, until around the turn of the nineteenth century, were excluded from formal medical training. However, many still practiced medicine in their homes and villages, and what they had learned came from shared knowledge and trial and error, rather than accepted official sources. A medical education might not have been a great help in any case. In the days before germ theory the causes of sickness and the reasons for recovery were not obvious. Any recoveries could be seen as miraculous … or the result of witchcraft.
Treating sickness and disease pre-germ theory was largely guesswork. All sorts of noxious compounds were administered to ailing individuals, and if they produced any effect on the body, be it vomiting, diarrhoea or sweating, it was seen as a good thing – and that was the practice of the so-called professionals. It is not hard to see how images of unofficial healers and herbalists (both men and women) stooping over boiling pots of herbs, roots and who-knows-what, could become a template for the image of a witch, especially when many of the concoctions they produced had such unpleasant effects on their patients.
Having said that, herbalists and traditional healers should not be dismissed as completely ignorant of the medical benefits of some of the plants and poultices they used. Some of the ingredients associated with traditional healing and witches’ potions have been found to be hugely beneficial to medicine once they have been isolated, tested and modified. Science has enabled us to identify the key components of some plants and test them to determine how and when they should be administered safely and effectively. Chemists have modified the structures of some of the compounds to reduce side-effects, make drugs more potent or lower their toxicity.
New Approach to Treating Alzheimer’s Disease
Alzheimer’s disease (AD) is one of the most common form of dementia. In search for new drugs for AD, the research team, led by Professor Mi Hee Lim of Natural Science at UNIST has developed a metal-based substance that works like a pair of genetic scissors to cut out amyloid-β (Aβ), the hallmark protein of AD.
The study has been featured on the cover of the January 2017 issue of the Journal of the American Chemical Society (JACS) and has been also selected as a JACS Spotlight article.
Alzheimer’s disease is the sixth leading cause of death among in older adults. The exact causes of Alzheimer’s disease are still unknown, but several factors are presumed to be causative agents. Among these, the aggregation of amyloid-β peptide (Aβ) has been implicated as a contributor to the formation of neuritic plaques, which are pathological hallmarks of Alzheimer’s disease (AD).
As therapeutics for AD, Professor Lim suggested a strategy that uses metal-based complexes for reducing the toxicity of the amyloid beta (Aβ). Althought various metal complexes have been suggested as therapeutics for AD, none of them work effectively in vivo.
The research team has found that they can hydrolyze amyloid-beta proteins using a crystal structure, called tetra-N methylated cyclam (TMC). Hydrolysis is the process that uses water molecules to split other molecules apart. The metal-mediated TMC structure uses the external water and cut off the binding of amyloid-beta protein effectively.
In this study, the following four metals (cobalt, nickel, copper and zinc) were placed at the center of the TMC structure. When the double-layered cobalt was added to the center, the hydrolysis activity was at the highest.
The research team reported that the cobalt-based metal complex (Co(II)(TMC)) had the potential to penetrate the blood brain barrier and the hydrolysis activity for nonamyloid protein was low. Moreover, the effects of this substance on the toxicity of amyloid-beta protein were also observed in living cell experiments.
“This material has a high therapeutic potential in the treatment of Alzheimer’s disease as it can penetrate the brain-vascular barrier and directly interact with the amyloid-beta protein in the brain,” says Professor Lim.
This study has also attracted attention by the editor of the Journal of the American Chemical Society. “Not only do they develop new materials, but they have been able to propose details of the working principles and experiments that support them,” according to the editor.
“As a scientist, this is such a great honor to know that our recent publication in JACS was highlighted in JACS Spotlights,” says Professor Lim. “This means that our research has not only been recognized as an important research, but also has caused a stir in academia.”
After the news of an accident in a French drug trial on Friday, you might be wondering what drug trials entail. Here’s a summary sheet on the drug discovery process to clear things up! http://wp.me/p4aPLT-1EZ
WATCH: A Macro Timelapse Highlights the Micro Movements of Spectacularly Colored Coral [video]
Individual bacterial cells have short memories. But groups of bacteria can develop a collective memory that can increase their tolerance to stress. This has been demonstrated experimentally for the first time in a study by Eawag and ETH Zurich scientists published in PNAS.
Roland Mathis, Martin Ackermann. Response of single bacterial cells to stress gives rise to complex history dependence at the population level. PNAS, March 7, 2016 DOI: 10.1073/pnas.1511509113
Experimental set-up with the bacterium Caulobacter crescentus in microfluidic chips: each chip comprises eight channels, with a bacterial population growing in each channel. The bacteria are attached to the glass surface by an adhesive stalk. When the bacterial cells divide, one of the two daughter cells remains in the channel, while the other is washed out. Using time-lapse microscopy, bacterial cell-division cycles and survival probabilities can thus be reconstructed. Credit: Stephanie Stutz
Happy Valentine’s Day! Hope everybody gets their share of dopamine and oxytocin today. #lovefeelings #scientificliteracy #braininlove #brainfeels
A tiny virus that may sting like a black widow spider.
That is one of the surprise discoveries made by a pair of Vanderbilt biologists when they sequenced the genome of a virus that attacks Wolbachia, a bacterial parasite that has successfully infected not only black widow spiders but more than half of all arthropod species, which include insects, spiders and crustaceans.
“Discovering DNA related to the black widow spider toxin gene came as a total surprise because it is the first time that a phage – a virus that infects bacteria – has been found carrying animal-like DNA,” said Associate Professor of Biological Sciences Seth Bordenstein. He and Senior Research Specialist Sarah Bordenstein reported the results of their study in a paper titled “Eukaryotic association module in phage WO genomes from Wolbachia” published Oct. 11 in the journal Nature Communications.
Sarah R. Bordenstein, Seth R. Bordenstein. Eukaryotic association module in phage WO genomes from Wolbachia. Nature Communications, 2016; 7: 13155 DOI: 10.1038/ncomms13155
DNA related to black widow spider toxin has been found in a bacterial virus. (iStock)
The oval shape in this electron microphotograph is a Wolbachia bacterium that has infected a Nasonia wasp. The small dots in the bacterium are WO phage particles. The inset shows them at a higher magnification. The white arrows in the inset point to the phage tails. The scale bar in the image is 200 nm and the bar in he inset is 100 nm. (Bordenstein Lab / Vanderbilt)
Ada Lovelace Day is an international celebration of the achievements of women in science, technology, engineering, math, and all related STEM fields.
The celebration is named in honor of English mathematician Augusta Ada King (1815-1852), Countess of Lovelace, known colloquially as Ada Lovelace. Lovelace, the daughter of Lord Byron, is sometimes considered the world’s first computer programmer for the algorithm she wrote for Charles Babbage’s analytical engine, one of the world’s first mechanical computers. Over the years there have been historical disagreements over the extent of Lovelace’s knowledge of the subject and the originality of the work she published in her article, “Sketch of the Analytical Engine, with Notes from the Translator,“ but Babbage himself seemed to dismiss such future claims in his memoir.
Check out the collection Science NetLinks put together for Women’s History Month for related resources to help all students understand the role women historically have played in the history of STEM development and those they play in current STEM fields.
Learn more.
Image Credit: Alfred Edward Chalon [Public domain], via Wikimedia Commons
With the help of two young patients with a unique neurological disorder, an initial study by scientists at the National Institutes of Health suggests that a gene called PIEZO2 controls specific aspects of human touch and proprioception, a “sixth sense” describing awareness of one’s body in space. Mutations in the gene caused the two to have movement and balance problems and the loss of some forms of touch. Despite their difficulties, they both appeared to cope with these challenges by relying heavily on vision and other senses.
“Our study highlights the critical importance of PIEZO2 and the senses it controls in our daily lives,” said Carsten G. Bönnemann, M.D., senior investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and a co-leader of the study published in the New England Journal of Medicine. “The results establish that PIEZO2 is a touch and proprioception gene in humans. Understanding its role in these senses may provide clues to a variety of neurological disorders.”
Dr. Bönnemann’s team uses cutting edge genetic techniques to help diagnose children around the world who have disorders that are difficult to characterize. The two patients in this study are unrelated, one nine and the other 19 years old. They have difficulties walking; hip, finger and foot deformities; and abnormally curved spines diagnosed as progressive scoliosis.
Working with the laboratory of Alexander T. Chesler, Ph.D., investigator at NIH’s National Center for Complementary and Integrative Health (NCCIH), the researchers discovered that the patients have mutations in the PIEZO2 gene that appear to block the normal production or activity of Piezo2 proteins in their cells. Piezo2 is what scientists call a mechanosensitive protein because it generates electrical nerve signals in response to changes in cell shape, such as when skin cells and neurons of the hand are pressed against a table. Studies in mice suggest that Piezo2 is found in the neurons that control touch and proprioception.
“As someone who studies Piezo2 in mice, working with these patients was humbling,” said Dr. Chesler. “Our results suggest they are touch-blind. The patient’s version of Piezo2 may not work, so their neurons cannot detect touch or limb movements.”
Further examinations at the NIH Clinical Center suggested the young patients lack body awareness. Blindfolding them made walking extremely difficult, causing them to stagger and stumble from side to side while assistants prevented them from falling. When the researchers compared the two patients with unaffected volunteers, they found that blindfolding the young patients made it harder for them to reliably reach for an object in front of their faces than it was for the volunteers. Without looking, the patients could not guess the direction their joints were being moved as well as the control subjects could.
The patients were also less sensitive to certain forms of touch. They could not feel vibrations from a buzzing tuning fork as well as the control subjects could. Nor could they tell the difference between one or two small ends of a caliper pressed firmly against their palms. Brain scans of one patient showed no response when the palm of her hand was brushed.
Nevertheless, the patients could feel other forms of touch. Stroking or brushing hairy skin is normally perceived as pleasant. Although they both felt the brushing of hairy skin, one claimed it felt prickly instead of the pleasant sensation reported by unaffected volunteers. Brain scans showed different activity patterns in response to brushing between unaffected volunteers and the patient who felt prickliness.
Despite these differences, the patients’ nervous systems appeared to be developing normally. They were able to feel pain, itch, and temperature normally; the nerves in their limbs conducted electricity rapidly; and their brains and cognitive abilities were similar to the control subjects of their age.
“What’s remarkable about these patients is how much their nervous systems compensate for their lack of touch and body awareness,” said Dr. Bönnemann. “It suggests the nervous system may have several alternate pathways that we can tap into when designing new therapies.”
Previous studies found that mutations in PIEZO2 may have various effects on the Piezo2 protein that may result in genetic musculoskeletal disorders, including distal arthrogryposis type 5, Gordon Syndrome, and Marden-Walker Syndrome. Drs. Bönnemann and Chesler concluded that the scoliosis and joint problems of the patients in this study suggest that Piezo2 is either directly required for the normal growth and alignment of the skeletal system or that touch and proprioception indirectly guide skeletal development.
“Our study demonstrates that bench and bedside research are connected by a two-way street,” said Dr. Chesler. “Results from basic laboratory research guided our examination of the children. Now we can take that knowledge back to the lab and use it to design future experiments investigating the role of PIEZO2 in nervous system and musculoskeletal development.”
A pharmacist and a little science sideblog. "Knowledge belongs to humanity, and is the torch which illuminates the world." - Louis Pasteur
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