Tag archive for techniques

Don’t Judge a Book by Its Cover … Judge by Its Smell

OldBooksA recently published article in the journal Analytical Chemistry discusses the distinct “aroma” produced by old books and aims to better describe – at the molecular level – that musty smell you encounter in the back rooms of libraries.  Volatile organic compounds (VOCs) are responsible for the odor … hundreds of them.  The exact combination of VOCs results from degradation pathways that are dependent on the original material composition – including the paper source, applied media (e.g. inks) and binding.  The exact composition of the off-gassing VOCs can hold valuable information regarding the condition of the materials and possible ways to aid in preservation.  Unfortunately, most testing methods used to date involve destructive sampling techniques.  The authors of this paper have devised a new approach that involves non-destructive head-space sampling of the emitted VOCs, combined with some advanced statistical analyses (a method termed “material degradomics” … a twist on more popular terms like proteomics or metabolomics).  Although hundreds of potential VOCs can be emitted, the authors focused in on 15 that can be used as markers to track the degradation of paper and help optimize its preservation.  Some of these markers include compounds such as benzaldehyde, nonanal, furfural, acetic acid, hexadecane, and 2-ethylhexanol (among others).

Now we can have a whole new appreciation for those leather-bound books and libraries that smell of rich mahogany (and VOCs)…

Anal. Chem., 2009, 81 (20), pp 8617–8622, DOI: 10.1021/ac9016049.

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New Gene Therapy Technique Provides a Breath of Fresh Air for Lung Donor Recipients

A group of researchers at the University Health Network of Toronto led by Dr. Shaf Keshavjee, developed a novel gene therapy technique that repaired donated lungs deemed too damaged to transplant. The group’s findings, “Functional Repair of Human Donor Lungs by IL-10 Gene Therapy” were published in the October 28, 2009 edition of the journal Science Translational Medicine. Their simple and effective technique could significantly increase the number of available lungs for people desperately in need.

Lungs-close-up-lrgAs it stands, only about 15 percent of lungs donated are usable for transplant. Because doctors injure delicate airways as they try to keep donors alive, or the brain death of the donors causes further damage through massive inflammation of the lung tissue. Lungs that make it to transplantation are still vulnerable to inflammation during the first 72 hours after surgery. Overall, only about 40% of lung transplant recipients survive five years after receiving their new lungs.

The research conducted by the University Health Network’s team focused on saving donated lungs that would otherwise be discarded and, eventually, to improve patient outcomes after transplantation. The most important component of their study is the interleukin-10 gene, IL-10. Among IL-10’s many roles is inhibiting the immune response to infection or foreign materials, like transplanted organs. The research strategy consisted of two parts. The first preserved lungs at normal body temperature in a protective dome called the Toronto XVIVO Lung Perfusion System. The dome continuously pumps oxygen devoid of blood, proteins, and nutrients into the injured lungs to mimic normal body conditions. This made it possible for the injured cells to regenerate themselves. In the second part, researchers injected an adenovirus vector, a common cold virus, along with the IL-10 gene through the windpipe into the lungs. After testing the technique with lungs from pigs and then human donors, the team concluded that the gene therapy significantly improved the ability of the lungs to take in oxygen as well as expel carbon dioxide. The therapy improved blood flow throughout the lungs and lasted for up to 30 days. None of the tested lungs were transplanted into patients; however, future plans include starting clinical trials on humans and testing whether this therapy could protect against post-transplant inflammation.

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Chemical Profile of Decomposition Acquired to Improve Technology for Disasters and Crime

Jones Press Conference-1wFor many years, search dogs have been the standard for the discovery and retrieval of human cadavers in disasters and crimes. The problems with this method are the cost and time it takes to train these search dogs. A device to detect the gases given off of a cadaver would be cheaper and less time consuming than training detection dogs. When a cadaver decomposes, a series of gases are given off over time. In order to develop a device that could detect these gases, experiments had to be performed to discover which gases are given off in different stages of decomposition and also to analyze how the environment affects decomposition in different situations.

Such a device could have been helpful in the search for survivors and cadavers of the earthquake in Indonesia in September. Rescue workers were still searching with detection dogs on the fourth day, and hopes for finding survivors are slim. With a device to detect gases released during decomposition, the search process may have been accelerated.

The first tests were performed on human cadavers, but the human cadavers were not delivered until about two or three days after the person had died. There are certain gases, such as cadaverine and putrescine, that are given off very early in the decomposition process and would therefore be undetected by the time the scientists received the cadavers. Dan Sykes, Ph.D., and student, Sarah A. Jones, from Pennsylvania State University, studied the decomposition of pigs because they display the same stages of decomposition as humans. Sykes and Jones euthanized three pigs and put them into containers that were open at the bottom to allow for insects and air to reach the bodies of the pigs. The gases given off during the decomposition process were collected and analyzed by a solid phase micro extraction (SPME) bundle with polyacrylate fibers. These polyacrylate fibers are polar and are commonly used to collect air samples. Similarly, the gases given off by the body were collected into the fibers. The samples were collected every six to twelve hours over the period of one week and then analyzed using GC-MS. Certain gases, such as indole and putrescine, were not given off until later in the decomposition process, but precursor molecules to these gases were detected, which helped to estimate when the gases would be given off. Using this method, Sykes and Jones were able to create a timeline of decomposition for the pigs, which closely resembles the timeline for the decomposition of a human cadaver. Now that the decomposition timeline has been created, it is possible to begin to set up different scenarios in order to apply the timeline to real life situations of decomposition in disasters and crime scenes.

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