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Blazing car murder of 1930 investigated

January 15th, 2014

A forensic team from the University of Leicester and Northumbria University has spearheaded an investigation which has shed new light on a murder case from 1930.

A team from the University of Leicester, led by Dr John Bond OBE from the Department of Chemistry and Dr Lisa Smith from the Department of Criminology worked with colleagues from Northumbria University, Northamptonshire Police and The Royal London Hospital Museum to tackle the riddle of the ‘Blazing Car Murder’ from over 80 years ago.

The case involved the murder of a male in a car fire in Hardingstone, Northamptonshire, on 6 November 1930. Alfred Rouse was convicted, and later hanged, at Bedford Gaol in March 1931, for murdering his victim who to this day, has not been identified.

At the time, a post mortem examination was carried out in the garage of the local public house by the Home Office-appointed pathologist Sir Bernard Spilsbury, working alongside another local pathologist.

Sir Spilsbury reported that lavender coloured material and light brown hair were found at the scene. It was further documented that the victim’s jawbone was removed to assist with possible identification and tissue samples taken for microscopical examination.

Two of these tissue samples are still in existence and archived in The Royal London Hospital Museum: one from the prostate to confirm the sex of the victim, and another from the lung to determine whether or not the victim was already dead before the fire was started.

In recent months, attention has turned to the fact that a man named William Briggs left his family home in London to attend a doctor’s appointment at around the same time the crime was committed — and was never seen or heard of again.

As part of their family ancestry research, the relatives of William Briggs wanted to verify earlier generations’ belief that their ancestor may have been Rouse’s car murder victim.

Last year, a number of William Briggs’s relatives approached Northamptonshire Police in an attempt to put the 83-year-old mystery to rest and finally reveal the identity of the victim.

They met with the Force’s curator and archivist Richard Cowley, discussed the story of the murder and were shown artefacts relating to the crime which, at the time received worldwide attention.

With the help of Northamptonshire Police, the family contacted University of Leicester academic Dr John Bond OBE. He and Dr Lisa Smith negotiated with The Royal London Hospital museum to allow one of the remaining tissue samples to be examined.

The slide was released with the approval of Professor Richard Trembath, at Queen Mary College University of London. The slide originates from the old Department of Forensic Medicine which formed part of The London Hospital Medical College. The College was merged with Queen Mary College in 1995.

The University of Leicester team considered whether there might just be enough mitochondrial DNA (mtDNA) left on the slide to get a profile to compare with mtDNA from the family.

Mitochondrial DNA is wholly inherited from the maternal line so it is essential to have an unbroken maternal line of descendants to test.

University of Leicester worked with the Northumbria University Centre for Forensic Science and Dr Eleanor Graham, a former member of staff at the University of Leicester, and Victoria Barlow to carry out DNA analysis on the samples to see if there was a match from the sample and the relatives.

Fortunately, the scientists obtained a full single male mtDNA profile from the slide to compare to the family.

Dr John Bond, from the University of Leicester said: “It’s been very interesting and rewarding working on such a famous, local murder case. It was quite a unique investigation to be involved in, as the perpetrator had been identified long ago and brought to justice while the victim’s identity remained unknown.

“It was a great example of how the scientific and criminological expertise at the University of Leicester and Northumbria University, working together with the police, could provide answers to this family after 83 years.”

Detective Chief Superintendent Paul Phillips from Northamptonshire Police said: “From our perspective this is a closed case, the offender Alfred Rouse was convicted of murder and hanged, but this has been a long-standing mystery in Northamptonshire as the identity of the victim has never been established.

“Our work at Northamptonshire Police is victim focused so I was delighted to learn of new opportunities to establish the identity of the victim through the development of forensic science.”

Dr Eleanor Graham from Northumbria University stated: “Projects such as this highlight the fact that forensic DNA analysis is not confined to ‘catching criminals’. DNA analysis also has a critical role to play in the identification of those who have been killed during criminal acts, accidents or natural disasters, which have occurred recently, or many years ago.”

The result is due to be revealed to the family on the BBC’s The One Show on a date to be fixed.

Blazing Car Murder background:

Alfred Rouse sustained a head wound in the First World War, which left him with a personality disorder, to the point that he was described as ‘a promiscuous rake with an enormous sexual appetite’.

Rouse was a commercial traveller who went all around the country and his promiscuous lifestyle resulted in him facing severe financial problems.

As a consequence, Rouse devised a plan to murder a homeless tramp who would not be missed by anyone which would enable him to stage his own death in a car accident and then disappear to start a new life free from financial restriction.

To that end, Rouse rendered his victim unconscious, placed him in the driver’s seat of his car and set the car alight.

Rouse was making his way from the scene but bumped into two local youths keen to see what was going on and take part in some late Bonfire Night celebrations.

This initial contact eventually led to Rouse’s arrest. He was convicted at Northampton Assizes and hanged in Bedford on 10 March 1931.

The local Herald newspaper suggested that the identity of Rouse’s victim ‘would likely remain a mystery forever.’ But will it………..?

Golden trap: Highly sensitive system to detect individual molecules

December 18th, 2013

The method’s high sensitivity lies in the customized environment for the substance of interest. Dresden’s Adrian Keller and his colleagues have constructed a type of “golden trap” capable of capturing the molecules and thereby enabling their detection. To this end, they arranged two tiny gold particles onto a substrate at predetermined distances. Next, the scientists anchored molecules of a dye called TAMRA within these gaps. They then irradiated the sample using laser light, which yielded what is known as a Raman spectrum. This optical method involves laser light that is scattered from the molecule which produces a spectrum that is like a fingerprint for this particular substance. Normally, Raman spectroscopy is a method with rather low sensitivity and a large number of molecules is needed to ensure their detection. By contrast, if the molecules are located near metallic surfaces, an astonishing effect is observed: the Raman signal is greatly amplified.

Such was the effect the HZDR researchers observed in their sample. HZDR researcher Adrian Keller explains: “An electric field develops within the gap between the gold spheres. If you select the proper dimensions, the field gets enhanced and we end up with so-called hot spots.” Next, the electric field, along with the incoming laser light, excites the molecules, which leads to enhanced Raman scattering. In other words, if the molecules are bound within these hot spots, their characteristic signals can be particularly well identified in the spectrum.

To construct their golden trap, the scientists chose the genetic material DNA. Its thread-like strands can be folded into different objects with arbitrary dimensions using multiple shorter DNA segments. This technique, known as DNA origami, is based on the chemical binding of complementary bases — the DNA strands essentially interlock like the two rows of a zipper. This allowed Adrian Keller and his colleagues to construct DNA triangles with edge lengths of approximately 100 nanometers. Two precisely placed anchors protrude from such a triangle which is used to attach two gold nanoparticles at predefined spacing.

In a first experiment, the researchers coated the tiny gold spheres with a sort of “DNA fur” containing also dye molecules. They then took a Raman spectrum of the sample and found that the TAMRA molecules could easily be detected. Since the gold nanoparticles’ fur coat is rather dense, Adrian Keller and his colleagues estimate that between 100 and 1,000 TAMRA molecules ultimately contribute to the detected signal. In control experiments, the researchers irradiated the furry gold spheres with laser light without arranging them on the DNA triangle. Here, only a very weak signal was detectable in the spectrum.

Yet the method is much more sensitive than that. In other experiments, the researchers attached a pair of naked gold nanoparticles to a DNA triangle and connected three single dye molecules to the DNA using additional anchors that were localized directly within the hot spots. Also in these Raman spectra, the dye’s signal could easily be identified. The tiny gold spheres’ optimal size was determined to be 25 nanometers, a size where the enhancement effect was especially large.

Finally, Keller and his colleagues carefully inserted only a single dye molecule into the gap between the two gold particles. Even this vanishingly small amount of TAMRA could still be detected. The surface illuminated by the laser beam contained a total of 17 DNA triangles. In other words, the signal originated from 17 single molecules.

“We were able to show that this method basically allows us to detect single molecules,” says Adrian Keller. Now, the researchers are planning on further extending the setup. For example, they plan to attach an anchor in the gap between the gold particles, capable of binding a molecule of interest — such as a protein, for instance. This way, any type of biomolecule could be analyzed: DNA, RNA, or proteins. And since every class of molecule produces characteristic Raman signals, you can test for the presence of several substances at the same time using specially prepared DNA triangles. Going forward, this detection method could also be integrated into a chip and used in medical diagnostics.

World’s most sensitive plasmon resonance sensor inspired by ancient Roman cup

December 12th, 2013

“With this device, the nanoplasmonic spectroscopy sensing, for the first time, becomes colorimetric sensing, requiring only naked eyes or ordinary visible color photography,” explained Logan Liu, an assistant professor of electrical and computer engineering and of bioengineering at Illinois. “It can be used for chemical imaging, biomolecular imaging, and integration to portable microfluidics devices for lab-on-chip-applications. His research team’s results were featured in the cover article of the inaugural edition of Advanced Optical Materials (AOM, optical section of Advanced Materials).

The Lycurgus cup was created by the Romans in 400 A.D. Made of a dichroic glass, the famous cup exhibits different colors depending on whether or not light is passing through it; red when lit from behind and green when lit from in front. It is also the origin of inspiration for all contemporary nanoplasmonics research — the study of optical phenomena in the nanoscale vicinity of metal surfaces.

“This dichroic effect was achieved by including tiny proportions of minutely ground gold and silver dust in the glass,” Liu added. “In our research, we have created a large-area high density array of a nanoscale Lycurgus cup using a transparent plastic substrate to achieve colorimetric sensing. The sensor consists of about one billion nano cups in an array with sub-wavelength opening and decorated with metal nanoparticles on side walls, having similar shape and properties as the Lycurgus cups displayed in a British museum. Liu and his team were particularly excited by the extraordinary characteristics of the material, yielding 100 times better sensitivity than any other reported nanoplasmonic device.

Colorimetric techniques are mainly attractive because of their low cost, use of inexpensive equipment, requirement of fewer signal transduction hardware, and above all, providing simple-to-understand results. Colorimetric sensor can be used for both qualitative analytic identification as well as quantitative analysis. The current design will also enable new technology development in the field of DNA/protein microarray.

“Our label-free colorimetric sensor eliminates the need of problematic fluorescence tagging of DNA/ protein molecules, and the hybridization of probe and target molecule is detected from the color change of the sensor,” stated Manas Gartia, first author of the article, “Colorimetrics: Colorimetric Plasmon Resonance Imaging Using Nano Lycurgus Cup Arrays.” “Our current sensor requires just a light source and a camera to complete the DNA sensing process. This opens the possibility for developing affordable, simple and sensitive mobile phone-based DNA microarray detector in near future. Due to its low cost, simplicity in design, and high sensitivity, we envisage the extensive use of the device for DNA microarrays, therapeutic antibody screening for drug discovery, and pathogen detection in resource poor setting.”

Gartia explained that light-matter interaction using sub-wavelength hole arrays gives rise to interesting optical phenomena such as surface plasmon polaritons (SPPs) mediated enhanced optical transmission (EOT). In case of EOT, more than expected amount of light can be transmitted through nanoholes on otherwise opaque metal thin films. Since the thin metal film has special optical property called surface plasmon resonance (SPR) which is affected by tiny amount surrounding materials, such device has been used as biosensing applications.

According to the researchers, most of the previous studies have mainly focused on manipulating in-plane two-dimensional (2D) EOT structures such as tuning the hole diameter, shape, or distance between the holes. In addition, most of the previous studies are concerned with straight holes only. Here, the EOT is mediated mainly by SPPs, which limits the sensitivity and figure of merits obtainable from such devices.

“Our current design employs 3D sub-wavelength tapered periodic hole array plasmonic structure. In contrast to the SPP mediated EOT, the proposed structure relies on Localized Surface Plasmon (LSP) mediated EOT,” Gartia said. “The advantage of LSPs is that the enhanced transmission at different wavelengths and with different dispersion properties can be tuned by controlling the size, shape, and materials of the 3D holes. The tapered geometry will funnel and adiabatically focus the photons on to the sub-wavelength plasmonic structure at the bottom, leading to large local electric field and enhancement of EOT.

“Secondly the localized resonance supported by 3D plasmonic structure will enable broadband tuning of optical transmission through controlling the shape, size, and period of holes as well as the shape, size, and period of metallic particles decorated at the side walls. In other words, we will have more controllability over tuning the resonance wavelengths of the sensor.”

Improved decoding of DNA for custom medical treatments

November 11th, 2013

The key to bringing about this revolutionary DNA-based medicine is the quick and accurate decoding of a patient’s genome. A genome is the unique sequence of special molecules along a chain of DNA that tells a cell’s machinery which proteins to produce, and when. Those crucial genome molecules are called “nucleobases,” and are known as adenine, thymine, cytosine, and guanine (or A, T, C, and G, for short). Prof. Meller and his team developed a way to record the As, Ts, Cs, and Gs in a person’s DNA by forcing a DNA molecule to slip through a tiny hole — called a “nanopore” — in a tiny silicon chip the size of the head of a nail.

(Just how small is a nanopore? It measures anywhere between 2 and 5 nanometers, or billionths of a meter, in diameter. In comparison, a human hair measures 100 micrometers, or millionths of a meter, in diameter.)

The scientists begin by dunking the DNA molecules in a combination of water and electrically charged salt molecules. As the saltwater flows through the nanopore, it creates an electric current. When a DNA molecule passes through the pore, however, the current is disrupted. And, the amount of current disruption depends on which A, T, C, or G is in the pore.

Therefore, to read the sequence of nucleobases, a scientist simply has to find out how much each base disrupts the electric current. With that information, he could read the sequence of DNA bases simply by logging the sequence of electrical disruptions as a DNA molecule passed through. There’s a catch, though. “To do this, each base must stay in the pore long enough to make it very clear how much current it blocks, so that one can correctly identify the nucleobase,” says Prof. Meller.

But DNA usually moves too quickly through the nanopores for Meller and his team to decode it. To slow the DNA down, they shone a green laser — no stronger than laser pointers used in classrooms — at the pore, which gave it a negative electric charge. The nanopore then attracted the positively charged potassium atoms in the saltwater. Those atoms, along with some of the water, moved towards the pore, creating a flow that blocked the movement of the DNA. “So, that creates a drag force on the DNA, slowing it down so that each base sites in the nanopore longer,” says Prof. Meller.

This method of reading DNA sequences is still under laboratory development. But Meller envisions a future in which the nanopore chip could be built into a portable device — about the size of a smartphone — that could be brought right to the patient.

The Technion research team collaborated with colleagues at Boston University on this project. The team’s results were published on the November 3rd in the online edition of Nature Nanotechnology.

Novel technique to detect fingerprints

October 25th, 2013

The product has been successfully put through its paces by the French Police and Gendarmerie as well as by Scotland Yard and the FBI. It has led to a publication on the website of the journal Forensic Science International and a patent has been filed.

Fingerprints are essential evidence in numerous criminal investigations. However, scientific police can find it difficult to make use of such fingerprints when they are too light or their contrast is too low. When someone places their finger on an object, they leave behind a trace composed of water, salts, fats, amino acids and, potentially, DNA. To reveal this latent trace, the most widely employed technique is fuming (2) of a cyanoacrylate compound (3), better known as “Super Glue.” This reacts with the elements present in the fingerprint and polymerizes, leaving a white deposit that technicians can then photograph and analyze. However, this technique can at times entail certain difficulties. For example, when the fingerprint support is of light color, the contrast with the fingerprint is too low to be photographed. Similarly, if the fingerprint is very light, the deposit will be too tenuous to obtain an exploitable image.

In this case, crime scene investigators can opt for a second treatment using a colorant, which turns the fingerprint fluorescent. However, this post-treatment poses several problems. The products in question are toxic and carcinogenic and have to be used in a fume cupboard, whose cost is usually beyond the means of most police stations. In addition, this process can require up to 48h and can degrade the fingerprints through leaching, which in most cases compromises the sampling of DNA.

In a bid to overcome these problems, numerous chemists have been trying for the past three decades to come up with a product allowing fluorescent fingerprints to be detected directly. This has now been achieved and researchers from the Laboratoire de Photophysique et Photochimie Supramoléculaire et Macromoléculaire (CNRS/ENS Cachan), in partnership with the specialized firm Crime Scene Technology, were the first to do so while complying with the standard conditions of use of a conventional cyanoacrylate. To manage this, they combined cyanoacrylate with a molecule of the tetrazine family (4), the smallest fluorescent colorants known to date. Tetrazine molecules are fumed along with the cyanoacrylate onto the fingerprint support and adhere to the deposit. In this way, using a simple UV lamp or forensic lighting techniques (see footnote 1), the fluorescent traces are visible and can be photographed.

Lumicyano(tm) offers excellent detection performance. In addition, it reduces costs and treatment times. Another advantage is that it does not destroy the DNA that can sometimes be extracted from fingerprints. Its operational efficiency has been successfully tested and validated, not just by the French Police and Gendarmerie but also by several other police forces throughout the world such as Scotland Yard and the FBI. Already available in numerous countries, Lumicyano(tm) is generating increasing interest among CSIs the world over. It will be presented at the forthcoming Worldwide Internal State Security Exhibition (Milipol, Paris 2013), scheduled for 19-22 November 2013 in Paris Nord Villepinte.

Notes

(1) Specialized in research and development in forensic sciences, in other words in all of the scientific and technical disciplines applied to criminal investigation.

(2) Fuming is a process that consists in spraying a product in the atmosphere of an airtight enclosure.

(3) In technical and scientific police investigations, the cyanoacrylate used is ethyl 2-cyanoacrylate, of empirical formula C6H7NO2. This monomer is also used as “instant” super glue.

(4) A tetrazine is an organic compound constituted of a six-atom aromatic ring, containing four atoms of nitrogen and two atoms of carbon. Beginning in 2003, Professor P. Audebert’s team was the first to focus on the fluorescence engineering of these colorants and to explore new physical properties of these molecules.

Authenticated brain waves improve driver security

September 6th, 2013

Isao Nakanishi of the Graduate School of Engineering, at Tottori University, and colleagues explain that conventional biometric systems commonly assume that authentication is “one-time-only,” but if an imposter replaces the authenticated user in a hijacked car, for instance, such systems have no way of verifying that the person currently driving the car is the legitimate driver and that the hijacker hasn’t thrown the owner from the car or tied them up in the boot. An authentication system based on password entry or iris scanning that repeatedly checks that the driver is the legal driver of the vehicle would be not be safe and so would be wholly unviable.

However, measuring the driver’s brain waves continually — via sensors in the headgear of the driver’s headgear — would be straightforward and would allow authentication that could not be spoofed by an imposter. If the wrong brain waves are measured, the vehicle is safely immobilized.

The Tottori team has now developed a system that can process electroencephalogram (EEG) signals in the alpha-beta band of the brain’s electrical activity and verify the signals it receives against a pre-programmed sample from the legitimate driver. “Brain waves are generated by the neural activities in the cerebral cortex; therefore, it is hidden in the body and cannot be bypassed,” the team explains.

Fundamentally, the system records the pattern of alpha-beta brain waves of a driver with their eyes open carrying out the normal functions of driving, given that this is the condition in which authentication is required. An alternative brain wave scan might have them with eyes closed and not carrying out any task. Importantly, the ongoing authentication of drivers using their brain waves would facilitate a simple way to preclude starting the engine if the driver is intoxicated with drugs or alcohol, or even just too tired because their brain waves would not match their normal pattern under such circumstances.

Making plants’ inner qualities visible

September 4th, 2013

A photographic airplane circles above an Australian vineyard in large arcs. An onboard camera takes pictures of the grapevines in regular intervals — anything but ordinary photos, though. Instead, this camera “looks” directly inside plants and delivers valuable information on their constituents to viticulturists. This enables viticulturists to systematically modify their cultivation in order to increase the yield of their grapevines by using hybrids with valuable properties — a real challenge under the basic conditions in Australia: The soil is dry and salty and summer temperatures are often extremely high.

This look at a grapevine’s “inner qualities” is made possible by special software that processes data from a hyperspectral camera, which records images of many adjacent wavelengths. Researchers at the Fraunhofer Institute for Factory Operation and Automation IFF in Magdeburg developed the software and the mathematical models it contains. “Every molecule absorbs light in a very specific wavelength range,” explains project manager Prof. Udo Seiffert. “The camera chip we use covers a large area of the relevant wavelength spectrum and, together with appropriate software, is able to scan the biochemical composition of every single recorded pixel precisely.” The camera thus delivers an overview of every constituent present in a plant in any significant concentration — a kind of hyperspectral “fingerprint.”

A camera delivers an overview of phytoconstituents

The raw data have to be processed appropriately in order to make them usable for clients. “Our data processing is based on mathematical modeling. On the basis of these algorithms, the software recognizes characteristic absorption properties of defined target constituents and filters them out of the raw data,” explains Seiffert. Initially, the researchers have to calibrate the software for the particular application so that it “knows” what constituents it should display. To do so, they photograph reference plants with their camera in order to obtain the fingerprint of the constituents. Then, the photographed tops of the plants are sent to a laboratory in order to analyze the concentrations of the constituents that are relevant to the user. Afterward, the laboratory results are entered into the mathematical model together with the hyperspectral fingerprint. The special thing about the software is its ability to correlate information autonomously and to save this knowledge. “Picture it somewhat like learning vocabulary,” explains Seiffert. Once the software has learned the correlation, it automatically filters the relevant constituents out of the hyperspectral camera images the next time. Then, a laboratory analysis is no longer needed for other series of measurements.

Looking inside plants creates effective new options for farmers to increase crop yield. For instance, certain metabolites — products of metabolism — provide information on the quality of a plant’s nutrition. Farmers can concentrate on cultivating those plants that thrive particularly well under the prevalent climatic conditions, thus enabling them to irrigate their fields less, for instance. Diseases such as fungal infections can also be detected faster thanks to hyperspectral technology. An infested plant activates defense mechanisms before an infection becomes outwardly visible — by dead leaves, stalks or mildew. Theses mechanisms indicate that the plant has detected and is combatting the infection. Previously, such tests required lengthy experiments in greenhouses. Not least, aerial photos can be used to detect sources of infection in a field quickly.

The first series of measurements with the project partner, the Australian Plant Phenomics Facility at the University of Adelaide, have concluded — the results are promising. At present, another use of the camera down under is in the planning stage. A demonstrator of the system’s use in greenhouses and laboratories will be on display at Booth E72 in Hall 9 at the BIOTECHNICA in Hannover from October 8 to 10, 2013.

Microelectronics: Automating cancer detection

September 1st, 2013

Genes that suppress tumors can be deactivated by the attachment of a methyl group to a specific DNA sequence — cytosine next to guanine — in their promoter region. The methyl group prevents the gene from being used as a template for protein synthesis and reduces the capacity of the cell to control its own proliferation.

Several well-established chemical methods exist for detecting such DNA methylation, but they are expensive, time-consuming and dependent on laboratory expertise. Shin and co-workers therefore investigated direct physical methods as an alternative. They focused particularly on silicon micro-ring resonators that amplify light at specific resonant frequencies. The resonators developed by the researchers are very sensitive detectors of a shift in light frequency, including the shift that occurs when a methyl group is attached or detached to DNA.

Shin and co-workers tested the capacity of silicon micro-ring resonators to discriminate between methylated and unmethylated forms of genes known to trigger cancer in bladder cells. They fashioned separate DNA probes to capture one or other form when they passed a solution of the genes, amplified by the polymerase chain reaction, over a silicon chip to which the probes were attached. The resonators clearly distinguished between the forms within five minutes. Moreover, the method allowed the team to quantify the density of methylation, which means the technique should be able to track changes in patterns of methylation.

“Our sensors could be widely useful for DNA methylation detection specifically and rapidly in the field,” says Shin.

He also notes that the team has published several research papers on using silicon micro-ring resonators. “Among the techniques we have published is a novel technique that can be integrated with the methylation-specific sensor to amplify the methylated DNA from low amounts of DNA,” he explains. “So, we are now trying to make a single microfluidic-based chip system that integrates several techniques, such as DNA extraction, conversion, amplification and detection.”

New forensic technique for analyzing lipstick traces

August 20th, 2013

Using a technique called Raman spectroscopy, which detects laser light, forensic investigators will be able to analyse lipstick marks left at a crime scene, such as on glasses, a tissue, or cigarette butts, without compromising the continuity of evidence as the sample will remain isolated.

Analysis of lipstick traces from crime scenes can be used to establish physical contact between two individuals, such as a victim and a suspect, or to place an individual at a crime scene.

The new technique is particularly significant for forensic science as current analysis of lipstick traces relies on destructive forensic techniques or human opinion.

Professor Michael Went of the University’s School of Physical Sciences said: ‘Continuity of evidence is of paramount importance in forensic science and can be maintained if there is no need to remove it from the bag. Raman spectroscopy is ideal as it can be performed through transparent layers, such as evidence bags. For forensic purposes Raman spectroscopy also has the advantages that microscopic samples can be analysed quickly and non-destructively.’

Raman spectroscopy is a process involving light and vibrational energy of chemical bonds. When a material — in this case lipstick — scatters light, most of the light is scattered at its original wavelength but a very small proportion is scattered at altered wavelengths due to changes in vibrational energy of the material’s molecules. This light is collected using a microscope to give a Raman spectrum which gives a characteristic vibrational fingerprint which can be compared to spectra of lipsticks of various types and brands. Hence it is possible to determine identity of the lipstick involved.

Research into applying the same method on other types of cosmetic evidence, such as foundation powders, eye-liners and skin creams is also underway.

Recognizing people by the way they walk

July 31st, 2013

Detecting suspicious behaviour (video surveillance), access control to buildings or to restricted areas and demographic analysis of a population in terms of gender and age range are just some of the possible applications of this technology.

The role of biometrics as an artificial intelligence field is the identification of an individual based on certain physical and non-transferable aspects of his/her body, such as fingerprint or facial recognition. These are just two of the most widely used and developed biometric sources because, as the researcher states, “they are very reliable and difficult to fake, although both require that the user is close to the sensor and collaborates in the recognition process, and we can not always count on that.” Hence the importance of advancing in complementary techniques.

We all have a very personal way of walking. “Although it is easy to manipulate and consciously change, each person walks in a different way,” says Mollineda. “There are experiments in which a person has to recognize familiar people just watching his/her silhouette in motion and the success rate is very high,” he adds. It has to be kept in mind that there are several factors that influence so that each person has a unique way of walking. From a video of the subject walking, the developed system distinguishes the background silhouette and it becomes a sequence of silhouettes, placed one upon the other, resulting in a summary image. This final representation stores all physical appearance and movement of the person walking, thus getting a unique mark for each of them.

Mollineda warns that, for now, due to the margin of error that gait recognition has in not controlled real scenarios, this technique would be much more effective if combined with facial recognition. “They are complementary methods: the way you walk can be detected from a distance and does not require a high-resolution image (it can be done even against a backlight and with poor lighting), while face recognition is performed close-up and with a high-resolution image. In this way, surveys could be carried out in a wider range of conditions or, if both methods are applicable, results could be more reliable thanks to contrasting hypotheses about the identity of an individual generated by two biometric systems.”