Spectroscopy – Page 14 – David Bradley

Raman best for breast cancer

Breast cancer remains the most common form of cancer among women but screening with mammography involves exposure to ionising radiation and suffers from a high rate of false positives that then require a definitive assay. In the December issue of the journal Biopolymers, researchers in India describe how Raman spectroscopy might be used to discriminate between normal, benign, and malignant breast tissue and so provide a simple and relatively non-invasive complement to a suspicious mammogram.

Murali Krishna of the Center for Laser Spectroscopy at Manipal Academy of Higher Education, in Karnataka and a visiting scientist at the University of Reims, France, and colleagues at Department of Surgical Oncology, Shirdi Sai Baba Cancer Hospital and Research Center and the Department of General Surgery at Kasturba Medical College, both part of Manipal, explain that, as with most cancers, survival rates depend on the stage at which diagnosis is made. More reliable screening and diagnosis methodology could thus improve survival rates.

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Double heart trouble

US researchers have demonstrated that MRI is twice as sensitive as other techniques at detecting early heart damage in patients with the immune system disorder sarcoidosis.

The early detection of heart problems in patients with sarcoidosis is imperative if the risk of dying from heart failure is to be reduced for such patients. Sarcoidosis is characterized by tiny inflammatory growths, granulomas, that cluster in the lungs, lymph nodes and under the skin, but can also form in the heart. Conventional techniques cannot differentiate between which patients who have cardiac granulomas will suffer long-term heart damage and those who will not.

Now, caridiologists at Duke University Medical Center have shown how MRI can reveal minute areas of heart damage before they reach a critical size. The earlier diagnosis might allow physicians to reduce the incidence of sudden cardiac death, a leading cause of death in patients with sarcoidosis.

The full story is available in my science news column on SpectroscopyNOW

Cocaine pregnancy test

Incidences of poisoning and drugs overdoses are common in hospital emergency rooms the world over. But, one thing medical staff lack to deal with such cases is a quick and easy way to identify the particular poison.

For an initial diagnosis, they usually rely on circumstantial evidence provided by anyone accompanying the patient or the victims themselves. Laboratory tests on saliva, urine, or blood samples can be long winded and often the definitive identification of the poison is possible only post mortem, which is obviously too late for the victim.

A dip-test for illicit drugs and poisons that is as quick and easy as a home pregnancy test-kit could save many lives according to US researchers. The team used UV-Vis spectroscopy to verify the performance of a proof of principle test on cocaine.

“Based on this principle, we should be able to develop rapid tests for the emergency diagnosis of a large number of drugs and poisons,” says Yi Lu of the University of Illinois in Urbana. The same approach could also be used to test for physiological molecules and environmental monitoring, he adds.

Get the complete hit at SpectroscopyNOW

In vaguely related news, it has been reported that street cocaine is now more dangerous than ever before as it is allegedly being cut with a cancer-causing chemical. That’s according to the UK’s Serious and Organised Crime Agency (Soca), which reports that there has been an increase in the use of “bulking” additives that resemble cocaine but don’t cut into drug dealer and supplier’s profits. The current scare surrounds the painkiller Phenacetin .

According to the current reports, phenacetin was originally banned from general use in 1968 because of a link to bladder and kidney cancer. The ban was later lifted, but doubts about its safety remain, hence the scare-mongering headlines from the BBC et al containing the phrase “cancer chemical”.

However, a little digging on PubChem reveals that this compound was actually banned because this non-prostaglandin synthase inhibitor was used as a drug of abuse and led to nephropathy in users –

Alchemists, crucibles and chemistry

What alchemist’s den would be complete without a crucible? The tough little vessels used for mixing all those odd ingredients, goat urine, cow’s blood, sweat, philosopher’s wool, saltpeter etc etc…

Now, the 500-year old mystery of how crucibles could survive all that chemical punishment and high temperatures has been revealed by archaeologists at University College London and Cardiff University.

Earlier research had demonstrated that the crucibles are found in archaeological sites across the world, including Scandinavia, Central Europe, Spain, Portugal, the UK, and even colonial America. Many researchers have tried to reproduce these vessels but have always failed.

Now, writing in Nature, the researchers reveal using petrographic, chemical and X-ray diffraction analysis that Hessian crucible makers made use of an advanced material only properly identified and named in the 20th century.

Marcos MartinÃ³n-Torres explains, “Our analysis of 50 Hessian and non-Hessian crucibles revealed that the secret component in their manufacture is an aluminium silicate known as mullite (Al₆Si₂O₁₃). Today mullite (not to be confused with mullet) is used in a wide range of modern conventional and advanced ceramics, such as building materials, electronic packaging devices, optical materials and catalytic converters, as well as in ceramic matrix composites such as thermal protection systems and liners for aircraft and stationary gas turbine engines.

Mullite was only described in the 20th century although the makers of crucibles were exploiting its properties almost half a millennium ago. It was produced by firing a crucible made from kaolinitic clay to above 1100 degrees.

Mullite is extremely resistant to heat, chemical and mechanical stresses, making it perfect for the Alchemist’s den. It is thanks to the availability of Hessian crucibles that the discoveries of several chemical elements and their thermochemical behaviour took place.

‘Crucible makers were not aware of mullite, but they mastered a very successful recipe, and that’s why they kept it constant, and secret, for centuries.’

Lock up the cat for safer drugs

stereoselective catalyst Canadian and Korean chemists have locked in a form of handedness into a common catalytic molecule that could make it useful for separating the building blocks of proteins, amino acids, into their chiral forms for biotech applications and drug development. The new locked up cat, might also be used to make purer and safer chemical starting materials for reactions in the drug, agrochemicals, and polymer industries.

Jik Chin and colleagues at the University of Toronto, Canada, working with Jong-In Hong’s team at Seoul National University, Korea to synthesise a cobalt(III) complex of the ligand "salen". Salen is a commonly used ligand in organometallic chemistry. It is a Schiff base formed from a two to one reaction of derivatives of salicylaldehyde and ethylene diamine. Complexes of this ligand are very effective catalysts for a wide range of reactions including epoxidation of alkenes.

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Heart disease and the death zone

atheroma Arterial plaques represent a "death zone" within the artery in which white blood cells that would otherwise clear away such fatty deposits are killed before they can do their job.

The result is that these plaques eventually reduce the blood supply to the heart causing heart problems. These plaques can break apart at any stage in a person’s life, although most commonly in middle age, whether they are otherwise fit or not.

Chinese researchers have now used analytical chemistry to determine the toxic components of arterial plaques that are so deadly to white blood cells. Their finding not only improves our understanding of this form of heart disease, but might one day lead to new approaches to treating atherosclerosis.

Find out more in the latest news from SpectroscopyNOW.com

More than a flash in the pan

$x-ray diffraction$ A 25 femtosecond snapshot of a stick man is all that was needed to prove that a new free-electron laser technique would work. Unfortunately, the poor old stick man evaporated within that split second into a 60,000 degree plasma.

Theory suggested that researchers might be able to obtain a single diffraction pattern from a large macromolecule, a virus, or even a cell using a suitably short and bright burst of X-rays from such a free-electron laser. Only a single set of data would be possible because the sample would be fried by this pulse. Now an international team has demonstrated that the technique works. Their results will mean that biologists might be able to obtain crystal structures from complex molecules, such as proteins, without even having to crystallise them first. They can just blast a sample with an X-ray pulse and get almost all the data they need.

You can grab the full story in my regular techy news round-up on SpectroscopyNOW.com

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Metallic BO

“The smell of iron upon contact with skin is ironically a type of human body odour,” explains Dietmar Glindemann. “That we are smelling the metal itself is actually an illusion.”

Many people notice a peculiar “metallic” smell when handling iron objects, such as tools, utensils, door handles, railings, firearms, coins, and other objects. But, iron untouched by human hand has a subtly different almost garlic like smell. Dietmar Glindemann of the University of Leipzig and his colleagues Andrea Dietrich at Virginia Polytechnic Institute and State University, and Hans-Joachim Staerk and Peter Kuschk of the Leipzig Environmental Research Center, Germany, have used a sophisticated analytical process to sniff out the reason why. It transpires that the metallic smell of iron that has been touched is a kind of body odour rather than a smelly metal.

More… (fixed link)

For those worrying about other kinds of BO, chemists and microbiologists have an answer to why some people smell the way they do. The research reported in Reactive Reports might one day lead to a new type of deodorant for even the smelliest of pits.

If you’re interested in how armpit scents can affect other people here’s an article from my days freelancing for The Guardian that explains how “eau d’armpit” might be used to treat pre-menstrual syndrome.

Cultural evolution in the lab

Adding a little culture to the chemical laboratory could help chemists find structures much faster than before. According to UK chemists, Samantha Chong and Maryjane Tremayne, of the University of Birmingham, combining the principles of social and biological evolution with a little fashion sense to make a new Cultural Differential Evolution algorithm allowed them to half the time it took to solve the structure of a molecule from its powder diffraction data.

Their research could have widespread application in solving a variety of global optimization problems in chemistry, nanoscience and bioinformatics.

The use of evolutionary algorithms is a relatively new approach to solving problems based on mimicking the principles of “natural selection” and “survival of the fittest”. The Birmingham team reasoned that the much more rapid social evolution experienced by humans, essentially fashion sense, could be merged into an evolutionary algorithm to help reduce the number of likely candidates for a particular structure much more quickly. They have now demonstrated how this works on two compounds, a previously unsolved structure and baicalein, the active ingredient in the Asian herbal medicine “Sho-saiko-to”.

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Not fade away

sn14a N st peters No one of whatever religious persuasion who visits the Sistine Chapel in Rome can fail to be impressed by the results of a 20-year restoration project that has brought Michelangelo’s frescoes back to their original level of artistry. Most notable is the brilliance of the sky blue that almost illuminates the Last Judgement on the altar wall of the chapel. But, recent NMR analysis of the ultramarine pigment used to produce this stunning blue suggests its tendency to fade could see the Last Judgement and other works ultimately perish.

Alexej Jerschow of New York University, Eleonora Del Federico of the Pratt Institute, and their colleagues have now discovered why the blue pigment fades. Their findings could provide art conservationists with vital information on how to protect works of art.

You can read the full story in the latest news round up from DB in SpectroscopyNOW.com