Spectroscopy – Page 18 – David Bradley

Solvent solution

Interest in alternative solvents to replace volatile organic compounds is on the increase, so improved understanding of the properties of these alternatives is needed. One class of solvents researchers are keen to learn more about are the room temperature ionic liquids (RTILs). Researchers have commonly used absorption or fluorescence to study solvation properties. But now scientists in Japan, have carried out a Raman spectroscopic study of a series of RTILs using diphenylcyclopropenone (DPCP) and phenol blue (PB) as probes to reveal information about solvent acceptor numbers. Their results could have implications for the use of these “green” solvents.

Find out more in my latest news write-up on SpectroscopyNOW (Raman channel)

Bubbly extractions

Air-assisted solvent extraction (AASX) process is an important new technique for the extraction of valuable metals such as copper, nickel, cobalt and uranium, as well as wastewater treatment where metal concentrations are typically low.

Now, a Canadian research team has discovered that it is the bubbles that play a critical role in providing a high solvent-specific surface area and ease of phase separation. Now, the team has used layer interferometry (in the UV-vis region) to measure the time-dependent thickness of a film formed by blowing an air bubble in kerosene-based solvents. They used Fourier transform infra-red spectroscopy to determine its chemical composition.

Read more in my news article on the IR channel on spectroscopyNOW.com

Understanding soil pollution

A lack of understanding of how problematic contaminants, such as polycyclic aromatic hydrocarbons (PAHs), pesticides, and herbicides interact with soil organic matter (SOM) is an issue that can hinder remediation of polluted sites, muddy the waters when it comes to determining the ultimate fate of pollutants, and reduce the viability of risk assessment models when considering new uses for brownfield and old industrial sites. Fortunately, Canadian scientists have now suggested that a range of techniques, including NMR and mass spectrometry, could clarify the various underlying mechanisms.

According to Myrna Simpson of the University of Toronto, Canada, a combination of conventional methods, such as equilibrium sorption and isotherm modelling, with NMR characterization of organic matter in soil, could help researchers get to the root of the problem.

Dig in at SpectroscopyNOW.com to read my complete article.

Lighting up the near infra red

A novel class of lanthanide compounds that emit in the near-infra-red could open up new possibilities for the use of NIR in biological imaging as well as leading to materials for optical amplifiers and light-emitting diodes (LEDs) operating at telecommunications frequencies.

According to Jean-Claude BÃ¼nzli of the EPFL, the Federal Polytechnic School in Lausanne, Switzerland, lanthanide compounds are of great interest in a number of fields because they produce narrow and easily recognisable emission lines in the NIR, they also have relatively long excited state lifetimes relative to organic chromophores. It is this latter characteristic of lanthanide coordination polymers that makes them of particular interest as they can be applied to time-resolved spectroscopy in analytical procedures allowing an enhanced signal-to-noise ratio and so much-improved sensitivity for luminescent analyses and imaging.

Follow my full write-up in the IR channel on SpectroscopyNOW.com.

Nanotechnology and medicine

X-ray imaging is a very mature, although not infallible, field of medicine, but it does not lend itself to the detection of small tumours or their metastases. Now, Sangeeta Bhatia in Boston, Massachusetts and colleagues at the Harvard-MIT Division of Health Sciences and Technology hope to remedy that by using iron oxide nanoparticles to allow MRI to visualize areas of tumor invasion.

The key to their novel imaging agent is a tumour-specific protease, which is found, as the name would suggest, primarily in and around tumour cells. Bhatia and her team engineered a method by which iron(III) oxide nanoparticles could form aggregate clusters under physiological conditions.

Find out more about how Bhatia and her colleagues hope to exploit nanotechnology to improve medicine in my current news round-up on SpectroscopyNOW.com

Spectral Science News

The latest round up of science news from David Bradley goes live at spectroscopyNOW.com today.

Among May 15’s postings:

Biomedical researchers have long thought that male sex hormones play a critical role in controlling cholesterol levels and lipids and in the development of atherosclerosis, a serious risk factor for heart disease, but new research from Wyeth Laboratories reveals that a protein receptor in the body called FXR, could have a key role, as well as the receptor for the male hormone androgen. “Our results suggest that the activity of FXR must now be considered in studies on the roles of male sex hormones in cardiovascular disease,” Wyeth’s Mark Evans told me.

Also, Chinese scientists have developed a new cheminformatics method for analysing the products of chemical reactions without researchers having to worry too much about any impurities that might be present.

Third up on the spectrometer this week – Coating an alloy with a biocompatible material is a key step in making implants, such as replacement hip joints, that sit comfortably with the patient’s skeleton and undergo osseointegration. A relatively new technique known as surface sol-gel processing (SSP), which is related to the well-known bulk sol-gel technique, can be used to prepare bioreactive nanostructured titanium oxides for adding a thin layer of material on a prosthetic joint. Understanding how calcium is subsequently deposited and phosphate released will help in the fine-tuning of the preparation for the most effective osseointegration.

Finally, watch out for bent copper under stress. Bend a metal bar, if you’re strong enough, and depending on certain microscopic conditions the bar will yield to curvature or snap. Understanding what occurs at the microscopic level when metals are placed under stress has been a key aspect of materials science research for decades. Now, researchers in Denmark and the USA have used a new technique for tracking the orientational changes that occur within the grains of metal as it stretched. The research shows how the accumulation of defects actually strengthens metals during deformation.

There’s plenty more news from the rest of the team on spectroscopyNOW too…

Pastel Chef and Chemist

In this week’s Alchemist I vaingloriously pronounced that oncologists might soon be able to image tumours as quickly and easily as radiologists view broken bones with X-rays.

Sciencebase contributor Dan Lednicer, a retired organic chemist turned pastel chef emailed me to point out that the statement regarding the power of X-rays required qualification:

“One day this last February, I happened to fall on my side in a parking lot. The persistent pain led me to get an X-ray the next day. This showed nothing out of the ordinary. When getting dressed one morning a week later, I found that any weight on my left leg led to excruciating pain. An X-ray in the emergency room at the hospital still showed nothing. It took an MRI (I almost wrote NMR!) to show a clean brake high up on the femur.

I now sport an impressive metal rod with a couple of appurtenances down the middle of that femur. This sails through metal detectors like a breeze, as it is made of titanium.”

So, it seems. X-rays are not the gods of imaging that my flippant remark would suggest. As to why titanium does not show up on airport metal detectors would make an interesting assignment for science class. Feel free to post your thoughts…

Science News with a Spectral Twist

Channelling toxins Novel treatments for high blood pressure and other disorders could emerge from high-resolution solid-state NMR studies that reveal how toxins affect the structure of potasssium channels in the cell.

Marc Baldus of the Max Planck Institute for Biophysical Chemistry in GÃ¶ttingen and colleagues in France and Germany have exploited a special protein synthesis procedure to follow how potassium channels and toxins combine to change the structure of the channel.

Zeolites step-by-step The evolution of zeolites has been followed by University of Minnesota chemical engineer Michael Tsapatsis and colleagues using microscopy and X-ray diffraction. Their study could lead to a new approach to designing and synthesizing novel variations on the zeolite theme for use as molecular sieves, catalysts, and sensors.

Analytical raft floats organic NLOs A combination of analytical techniques has proved its worth in assessing a series of non-linear optical materials for use in future organic optoelectronics devices. Juan LÃ³pez Navarrete of the University of Malaga, Spain, and colleagues at the University of Zaragoza-CSIC and the University of Minnesota, Morris, USA, used UV-vis, IR, and Raman spectroscopy, nonlinear optical (NLO) measurements, X-ray diffraction, and cyclic voltammetry to assess the properties of a series of tricyanovinyl (TCV)-substituted oligothiophenes.

A particularly golden study US researchers have devised what they describe as a very efficient method for making well-defined gold nanoparticles with equal numbers of hydrophobic and hydrophilic arms. The V-shaped arms are alternately distributed across the surface of 2 nanometre gold core particles. The solubility of these nanoparticles in a wide range of solvents means that they should be amenable to further processing with various chemical modifiers. Such nanoparticles have potential in optoelectronics, catalysis, and biomedical applications.

A Cadmium Conundrum

How do you clean up waste water contaminated with the deadly metal cadmium and what do you do with the resulting material? French scientists reckon they have found the answer.

The mineral hydroxyapatite, like its natural counterpart found in tooth and bone, has an affinity for the toxic heavy metal cadmium, they say. Now, they have used X-ray diffraction spectroscopic analysis, and electron microscopy to follow the kinetics of uptake and release of this metal from hydroxyapatite and have demonstrated that a solid apatite solution of cadmium is formed. Their findings could have implications for the dual use of this material as a decontaminant and a storage medium for cadmium.

Read on…

Improved Biological Imaging

French researchers have now demonstrated a way to circumvent one of the main problems associated with cellular imaging and can obtain nanomolar concentration readings even for complex biological samples using their approach.

The method has led to an extension of the use of spectroscopy and spectro-imaging to many more parameters associated with cellular activity in both cultured and xenografted cells, and living tissues. No other analytical technique is available that can analyse tissue sections without embedding, fixation, or reagents adding, at the resolution and sensitivity obtained by the team.

Read on…