The Experts below are selected from a list of 56307 Experts worldwide ranked by ideXlab platform

Mariya Goray - One of the best experts on this subject based on the ideXlab platform.

  • investigation of secondary dna transfer of skin cells under controlled test conditions
    Legal Medicine, 2010
    Co-Authors: Mariya Goray, John R Mitchell, Roland A H Van Oorschot
    Abstract:

    Abstract There is a paucity of data on the relative transfer rates of deposited Biological Substances which could assist evaluation of the probability of given crime scene scenarios, especially for those relating to objects originally touched by hand. This investigation examines factors that may influence the secondary transfer of DNA from this source, including the freshness of the deposit, the nature of the primary and secondary substrate and the manner of contact between the surfaces. The transfer rates showed that both the primary and secondary type of substrate and the manner of contact are important factors influencing transfer of skin cells, but, unlike other Biological fluids, such as blood and saliva, the freshness of the deposit in most instances is not. Skin cells deposited on a non-porous primary substrate transferred more readily to subsequent substrates than those deposited on a porous substrate. Porous secondary substrates, however, facilitated transfer more readily than non-porous secondary substrates, from both porous and non-porous surfaces. Friction as the manner of contact significantly increased the rate of transfer. The findings of this study improve our general understanding of the transfer of DNA material contained in fingerprints that is left on a surface, and assist in the evaluation of the probability of secondary and further DNA transfer under specific conditions.

  • secondary dna transfer of Biological Substances under varying test conditions
    Forensic Science International-genetics, 2010
    Co-Authors: Mariya Goray, Ecec E Eken, R J Mitchell, Roland A H Van Oorschot
    Abstract:

    This research investigates factors that may influence the secondary transfer of DNA. These include the type of Biological substance deposited, the nature of the primary and secondary substrate, moisture content of the deposit and type of contact between the surfaces. Results showed that secondary transfer is significantly affected by both the type of primary substrate and the moisture (wetness) of the Biological sample. Porous substrates and/or dry samples diminished transfer (with on average only 0.36% of Biological material being transferred from one site to another), whereas non-porous substrates and/or wet samples facilitated transfer events (approximately 50–95% of Biological material was transferred from one site to another). Further, the type of secondary substrate also influenced transfer rate, with porous surfaces, absorbing transferred Biological Substances more readily than non-porous ones. No significant differences were observed among the Biological Substances tested (pure DNA, blood and saliva). Friction contact between the two substrates significantly enhanced secondary transfer compared to either passive or pressure contact. These preliminary results will assist in developing general assumptions when estimating probability of a secondary DNA transfer event under simple conditions.

  • impact of relevant variables on the transfer of Biological Substances
    Forensic Science International: Genetics Supplement Series, 2009
    Co-Authors: Roland A H Van Oorschot, Mariya Goray, Ece Eken, R J Mitchell
    Abstract:

    Abstract There is a paucity of data on the relative amounts of DNA containing material that is likely to be transferred given specific casework scenarios that incorporate multiple transfer steps. Availability and application of such data could be helpful in estimating the probability of a given set of circumstances actually occurring. Here we utilise data on transfer percentages, given knowledge of specific variables (type of Biological substance, level of moisture of the Biological substance, the substrate on which the sample is located, the substrate with which it comes into contact, and the manner of contact), as determined by Goray et al. [1,2] to extrapolate the amount of DNA expected to be retrieved from a targeted sample area, under particular multi-transfer step scenarios. We demonstrate that, in many scenarios incorporating multiple transfer steps, unrealistically large amounts of Biological material would need to be present at source to generate a detectable level of DNA from the targeted crime scene surface. These findings will assist in comparing the likelihood of postulated alternative crime scenarios involving DNA transfer, at the investigation stage and/or during court proceedings.

Vincenzo Schettino - One of the best experts on this subject based on the ideXlab platform.

  • sers investigation of possible extraterrestrial life traces experimental adsorption of adenine on a martian meteorite
    Meteoritics & Planetary Science, 2012
    Co-Authors: Stefano Caporali, Marco Pagliai, Giovanni Pratesi, Vincenzo Schettino, V Moggicecchi, Maurizio Munizmiranda
    Abstract:

    Abstract– The identification of adenine by surface enhanced Raman scattering (SERS) on different mineral phases of a Martian meteorite Dar al Gani (DaG) 670 has been adopted as a test to verify the capability of this technique to detect trace amounts of organic or Biological Substances deposited over, or contained in, extraterrestrial materials. Raman spectra of different phases of meteorite (olivine, pyroxene, and ilmenite), representative of Martian basaltic rocks, have been measured by three laser sources with wavelengths at 785, 632.8, and 514.5 nm, coupled to a confocal micro-Raman apparatus. Adenine deposited on the Martian meteorite cannot be observed in the normal Raman spectra; when, instead, meteorite is treated with silver colloidal nanoparticles, the SERS bands of adenine are strongly enhanced, allowing an easy and simple identification of this nucleobase at subpicogram level.

  • surface enhanced raman scattering investigation of nucleobases adsorbed on samples of martian analogue material
    Spectroscopy Letters, 2011
    Co-Authors: Stefano Caporali, Marco Pagliai, Giovanni Pratesi, Vincenzo Schettino
    Abstract:

    ABSTRACT The identification of two nucleobases (adenine and hypoxanthine) by Surface-Enhanced Raman Scattering (SERS) on different mineral substrates was adopted as a test case to verify the capability of this analytical technique to detect trace amounts of organic or Biological Substances deposited over, or contained in, Martian regolith. Raman spectra were collected on polished samples of calcite, dolomite, magnesite, siderite, anhydrite, and gypsum, onto which traces of nucleobases were added. While spectroscopic features of the two nucleobases could not be observed in normal Raman spectrum, the addition of silver nanoparticles allowed easy identification of the vibrational bands characteristic of the two nucleobases.

Zhijie Huan - One of the best experts on this subject based on the ideXlab platform.

  • closed loop control for trajectory tracking of a microparticle based on input to state stability through an electromagnetic manipulation system
    IEEE Access, 2020
    Co-Authors: Zhixiong Zhong, Zhijie Huan
    Abstract:

    Magnetic force-based manipulation has several advantages, including its minimally invasive feature and insensitivity to Biological Substances. Consequently, it has exhibited considerable potential in many medical applications, such as targeted delivery in precise medicine, in which microparticles are driven to the desired regions precisely in vivo. This study investigates an automated and accurate delivery of magnetic microparticles using a self-constructed electromagnetic coil system. After establishing a simplified second-order dynamic model of microparticles suspended in a fluidic environment, a visual-based automated controller that incorporates the concept of input-to-state stability (ISS) into fault-tolerant technique is developed. This controller enables microparticles to follow a desired trajectory under model uncertainties and environmental disturbances, and address the problem that the actual magnetic driving force may not reach the required value due to magnetic loss in the coil system simultaneously. Input constraint of the magnetic force provided by the system due to device capability is also considered in the fault-tolerant ISS-based controller design. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed approach.

  • closed loop control of trajectory tracking a microparticle through an electromagnetic manipulation system
    World Congress on Intelligent Control and Automation, 2018
    Co-Authors: Zhijie Huan, Hao Yang, Mingyang Xie
    Abstract:

    With the advantages of minimally invasive feature and insensitivity to Biological Substances, magnetic force-based manipulation has exhibited great biomedical application potential, where microparticles are driven to follow desired trajectories. This study proposes a closed-loop control approach for automated manipulation of magnetic microbeads using a self-made electromagnetic coil system. A visual-based closed-loop controller that incorporates the concept of input-to-state stability is developed, which enables the bead to follow the desired trajectory successfully, while maintaining the tracking error within a local area under model uncertainties and environmental disturbances. A high-gain observer is further designed to estimate the bead velocity, which solves the difficulty of measuring the bead velocity via visual feedback. Simulation and experimental results demonstrate that the proposed method could be effective.

Roland A H Van Oorschot - One of the best experts on this subject based on the ideXlab platform.

  • investigation of secondary dna transfer of skin cells under controlled test conditions
    Legal Medicine, 2010
    Co-Authors: Mariya Goray, John R Mitchell, Roland A H Van Oorschot
    Abstract:

    Abstract There is a paucity of data on the relative transfer rates of deposited Biological Substances which could assist evaluation of the probability of given crime scene scenarios, especially for those relating to objects originally touched by hand. This investigation examines factors that may influence the secondary transfer of DNA from this source, including the freshness of the deposit, the nature of the primary and secondary substrate and the manner of contact between the surfaces. The transfer rates showed that both the primary and secondary type of substrate and the manner of contact are important factors influencing transfer of skin cells, but, unlike other Biological fluids, such as blood and saliva, the freshness of the deposit in most instances is not. Skin cells deposited on a non-porous primary substrate transferred more readily to subsequent substrates than those deposited on a porous substrate. Porous secondary substrates, however, facilitated transfer more readily than non-porous secondary substrates, from both porous and non-porous surfaces. Friction as the manner of contact significantly increased the rate of transfer. The findings of this study improve our general understanding of the transfer of DNA material contained in fingerprints that is left on a surface, and assist in the evaluation of the probability of secondary and further DNA transfer under specific conditions.

  • secondary dna transfer of Biological Substances under varying test conditions
    Forensic Science International-genetics, 2010
    Co-Authors: Mariya Goray, Ecec E Eken, R J Mitchell, Roland A H Van Oorschot
    Abstract:

    This research investigates factors that may influence the secondary transfer of DNA. These include the type of Biological substance deposited, the nature of the primary and secondary substrate, moisture content of the deposit and type of contact between the surfaces. Results showed that secondary transfer is significantly affected by both the type of primary substrate and the moisture (wetness) of the Biological sample. Porous substrates and/or dry samples diminished transfer (with on average only 0.36% of Biological material being transferred from one site to another), whereas non-porous substrates and/or wet samples facilitated transfer events (approximately 50–95% of Biological material was transferred from one site to another). Further, the type of secondary substrate also influenced transfer rate, with porous surfaces, absorbing transferred Biological Substances more readily than non-porous ones. No significant differences were observed among the Biological Substances tested (pure DNA, blood and saliva). Friction contact between the two substrates significantly enhanced secondary transfer compared to either passive or pressure contact. These preliminary results will assist in developing general assumptions when estimating probability of a secondary DNA transfer event under simple conditions.

Michael J Natan - One of the best experts on this subject based on the ideXlab platform.

  • surface enhanced raman spectroscopy and homeland security a perfect match
    ACS Nano, 2009
    Co-Authors: Rebecca Stoermer Golightly, William E Doering, Michael J Natan
    Abstract:

    This Nano Focus article reviews recent developments in surface-enhanced Raman spectroscopy (SERS) and its application to homeland security. It is based on invited talks given at the "Nanorods and Microparticles for Homeland Security" symposium, which was organized by one of the authors and presented at the 238th ACS National Meeting and Exhibition in Washington, DC. The three-day symposium included approximately 25 experts from academia, industry, and national laboratories and included both SERS and non-SERS approaches to detection of chemical and Biological Substances relevant to homeland security, as well as fundamental advances. Here, we focus on SERS and how it is uniquely positioned to have an impact in a field whose importance is increasing rapidly. We describe some technical challenges that remain and offer a glimpse of what form solutions might take.