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Gas chromatography with state-of-the-art micromachined differential mobility detection: operation and industrial applications.

Ion mobility spectrometry (IMS) has potential analytical applications in very diverse fields such as chemical, petrochemical, environmental, and, more recently, in drug, chemical warfare agent, and explosives detection. Commercially available IMS instruments are based on time-of-flight (TOF) mass spectrometry. IMS is inherently suitable for field operation as it uses relatively simple microfluidic devices and operates at atmospheric pressure. It is portable, highly sensitive with tunable selectivity, yet can be produced at relatively low cost. Key limitations of this analytical detection technique are low duty cycle, ion cluster formation, short linear dynamic range, and restriction to only positive or negative ion collection in a single analysis. Microelectromechanical system, radio frequency modulated IMS (MEMS RF-IMS), also known as differential mobility spectrometry, has recently been developed and commercialized. The technology is based on IMS, and MEMS RF-IMS offers substantially better performance. In this study, the strengths and limitations of the recently introduced differential mobility detector when used with gas chromatography in trace analyses are discussed and illustrated with applications of industrial significance.

Journal Article↗

Suicide bombers form a new injury profile.

BACKGROUND: Recent explosions of suicide bombers introduced new and unique profiles of injury. Explosives frequently included small metal parts, increasing severity of injuries, challenging both physicians and healthcare systems. Timely detonation in crowded and confined spaces further increased explosion effect. METHODS: Israel National Trauma Registry data on hospitalized terror casualties between October 1, 2000 and December 31, 2004 were analyzed. RESULTS: A total of 1155 patients injured by explosion were studied. Nearly 30% suffered severe to critical injuries (ISS > or = 16); severe injuries (AIS > or = 3) were more prevalent than in other trauma. Triage has changed as metal parts contained in bombs penetrate the human body with great force and may result in tiny entry wounds easily concealed by hair, clothes etc. A total of 36.6% had a computed tomography (CT), 26.8% had ultrasound scanning, and 53.2% had an x-ray in the emergency department. From the emergency department, 28.3% went directly to the operating room, 10.1% to the intensive care unit, and 58.4% directly to the ward. Injuries were mostly internal, open wounds, and burns, with an excess of injuries to nerves and to blood vessels compared with other trauma mechanisms. A high rate of surgical procedures was recorded, including thoracotomies, laparotomies, craniotomies, and vascular surgery. In certain cases, there were simultaneous multiple injuries that required competing forms of treatment, such as burns and blast lung. CONCLUSIONS: Bombs containing metal fragments detonated by suicide bombers in crowded locations change patterns and severity of injury in a civil population. Specific injuries will require tailored approaches, an open mind, and close collaboration and cooperation between trauma surgeons to share experience, opinions, and ideas. Findings presented have implications for triage, diagnosis, treatment, hospital organization, and the definition of surge capacity.

Adolescent↗

Zero-valent iron treatment of RDX-containing and perchlorate-containing wastewaters from an ammunition-manufacturing plant at elevated temperatures.

The use of zero-valent iron for treating wastewaters containing RDX and perchlorate from an army ammunition plant (AAP) in the USA at elevated temperatures and moderately elevated temperature with chemical addition was evaluated through batch and column experiments. RDX in the wastewater was completely removed in an iron column after 6.4 minutes. Increasing the temperature to 75 degrees C decreased the required retention time to 2.1 minutes for complete RDX removal. Perchlorate in the wastewater was completely removed by iron at an elevated temperature of 150 degrees C in batch reactors in 6 hours without pH control. Significant reduction of perchlorate by zero-valent iron was also achieved at a more moderate temperature (75 degrees C) through use of a 0.2 M acetate buffer. Based on the evaluation results, we propose two innovative processes for treating RDX-containing and perchlorate-containing wastewaters: a temperature and pressure-controlled batch iron reactor and subsequent oxidation by existing industrial wastewater treatment plant; and reduction by consecutive iron columns with heating and acid addition capabilities and subsequent oxidation.

Explosive Agents↗

Challenges to military working dog management and care in the Kuwait theater of operation.

In a combat environment, troop safety and installation security are paramount. Documentation of the frequent use of explosive devices by insurgents in Southwest Asia has increased the need for augmentation of defensive capabilities. Military working dogs (MWDs) are trained and certified to perform missions supporting security and detection of explosives. Challenges arise in theater because the number of certified dogs available can be limited and the standards of housing and care that are available in the continental United States are not usually available in a combat theater. Planning, preparation, and training of MWD handlers,animal care specialists, and Veterinary Corps officers will maximize mission performance and MWD health. Some of th echallenges and needs associated with management and care of the MWDs in the Kuwait theater of operation are discussed. Suggested improvements to the current deployment readiness paradigm are offered from the perspective of a staff veterinarian who was deployed in support of Operation Iraqi Freedom in 2004.

Animals↗

[Raman spectrum of nano-graphite synthesized by explosive detonation].

The nano-graphite powder synthesized by the detonation of explosives with negative oxygen balance is a new powder material with potential applications. In this work, the preparation of nano-graphite powder in steel chamber by pure TNT (trinitrotoluene) explosives has been introduced. In the synthesis process, the protective gases in the steel chamber are N2, CO2 and Ar, and the pressure is 0.25-2 atm. Raman spectrum of the nano-graphite was measured. The characteristic Raman band assigned to sp2 of graphite has been observed at about 1 585 cm(-1) with half-peak width of 22 cm(-1). The peak shifted to a higher frequency by 5 cm(-1) compared with that of bulk graphite. The authors explain this blue shift phenomenon by size effect. The average size of nanographite from Raman measurement is 2.97-3.97 nm. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to measure the structure and particle size of the nano-graphite. The crystallite size of nano-graphite estimated from XRD andTEM are 2.58 nm (acid untreated) and 1.86 nm (acid treated) respectively, which is in accord with the results of the measurement approximately.

Argon↗

[Studies on nano-diamond prepared by explosive detonation by Raman and infrared spectroscopy].

Nano-diamond was synthesized by TNT/RDX explosives detonation in a steel chamber and characterized by X-ray diffraction (XRD), laser Raman spectroscopy, and infrared spectroscopy. XRD results indicate that nano-diamond has cubic diamond structure. The parameter of unit cell of nano-diamond is 0.359 23 nm and is 0.72% larger than that of the bulk diamond. The high-density defects and other impurity atoms in the nano-diamond structure may lead to the large lattice constant. The examination results of Raman spectra show that the Raman band is broader and shifts to l ow frequency by 3 cm(-1), because the size of nano-diamond reaches nanometer order. There is little graphite in the nano-diamond. There are two peaks in FTIR of the nano-diamond, which are characteristic peaks of diamond at 1 262 and 1 134 cm(-1). Besides these two peaks, there are six peaks at 3 422, 1 643, 2 971, 2 930, 2 857 and 1 788 cm(-1) respectively. The FTIR bands at 2 930 and 2 857 cm(-1) are the antisymmetrical and symmetrical stretch vibration absorption spectra of CH2 respectively. The 3 422 cm(-1) is the stretch vibration absorption peak of O-H. The 1 634 cm(-1) confirms that there are H2O in the nano-diamond. The 2 971 cm(-1) is the antisymmetrical stretch vibration absorption peak of CH3. The 1 788 cm(-1) is the stretch vibration absorption peak of C=O. These indicate that there are H and O elements in the nano-diamond. From the mechanism of the nano-diamond, the authors discuss the reason for the vibration absorption peaks of O-H, CH2, CH3, and C=O, existing in the FTIR of the nano-diamond.

Algorithms↗

[A peculiar speech disorder due to bomb injury of the brain].

Oslo was bombed by British bombers 6 September 1941, and a 28-year-old woman was hit on the head by a bomb fragment. She was seriously wounded with a large defect in the cranium frontally on the left side, and it was believed that she was not going to survive. She was unconscious for 3-4 days, and when she woke up she had right-sided hemiplegia and complete aphasia. She gradually recovered, and two months later she was discharged from hospital. Remarkably, the brain damage had altered her melody of language, and she spoke with a German-like accent. This led to problems for her during the war: she was for example not served in shops. The case story was published after the war by the Norwegian neurologist Georg Herman Monrad-Krohn (1884-1964), and it is the best known case of the so-called foreign accent syndrome. In this paper, this rare syndrome is presented, emphasising Monrad-Krohn's patient and based on his writings and the patient's medical record.

Adult↗

Professor Joseph Warren Horton (1889-1967): biological engineer.

Joseph Warren Horton graduated with a degree in electrical engineering from the Massachusetts Institute of Technology (MIT) in 1914. He became involved in the early development of electrical measurement devices, televised image transmission, and the detection of underwater sound transmission. In the mid-1930s he was appointed the first leader of the newly created Department of Biological Engineering at MIT and in this position he made major contributions to the application of physics to human physiology, in particular by increasing the safety of explosive inhalational anaesthetic agents.

Academies and Institutes↗

Clinical experiences with G17DT in gastrointestinal malignancies.

The development of new agents for the treatment of gastrointestinal malignancies is increasing in pace and importance. The discovery of novel targets, namely the epidermal growth factor receptor and vascular endothelial growth factor, have sparked an explosion of new agents being tested in gastrointestinal malignancies. Clearly, novel agents and approaches are required. G17DT is a novel immunoconjugate designed to elicit a humoral response against the N-terminal end of G17 gastrin. In this overview, the authors summarize the clinical research focused on gastrointestinal tract cancers to date. In total, there is a clear signal of efficacy with this compound, although further testing is required in order for this efficacy to be demonstrated in a manner that will support regulatory approval.

Animals↗

Microchip capillary electrophoresis coupled with a boron-doped diamond electrode-based electrochemical detector.

The attractive behavior and advantages of a diamond electrode detector for a micromachined capillary electrophoresis (CE) system are discussed. A chemically vapor-deposited boron-doped diamond (BDD) film band (0.3 x 6.0 mm) electrode is used for end-column amperomettic detection. The favorable performance of the diamond electrode microchip detector is indicated from comparison to a commonly used thick-film carbon detector. The diamond electrode offers enhanced sensitivity, lower noise levels, and sharper peaks for several groups of important anaytes (nitroaromatic explosives, organophosphate nerve agents, phenols). The favorable signal-to-background characteristics of the BDD-based CE detector are coupled with a greatly improved resistance to surface fouling and greater isolation from high separation voltages. The enhanced stability is indicated from a RSD of 0.8% for 60 repetitive measurements of 5 ppm 2,4,6-trinitrotoluene (vs RSD of 10.8% at the thick-film carbon electrode). A highly linear response is obtained for the explosives 1,3-dinitrobenzene and 2,4-dinitrotoluene over the 200-1,400 ppb range, with detection limits of 70 and 110 ppb, respectively. Factors influencing the performance of the BDD detector are assessed and optimized. The attractive properties of BDD make it very promising material for electrochemical detection in CE microchip systems and other micromachined flow analyzers.

Air Pollutants, Occupational↗

Explosion risk from swimming pool chlorinators and review of chlorine toxicity.

Two patients were admitted to the hospital emergency room in respiratory distress after an accidental explosion involving chlorinating agents for the swimming pool. The two primary agents involved were calcium hypochlorite and trichloro-s-triazinetrione; both are commonly used chlorinating agents. These chemicals were tested in a bomb apparatus measuring temperature and gas production. Combining the two chlorinators at 2, 6, 12, or 18 g of each produced a progressive increase in gas production from 234 to 1422 mL. The temperature increased from 30 degrees C at 2 g to 63 degrees C at 18 g. The time to complete the reaction decreased from 6.2 minutes at 2 g to 3.8 minutes at 18 g. The third run at the 18 g level resulted in an explosion. The results indicate that gas generation is dependent on both products. The addition of organic material was abandoned because of the explosive nature of the reaction. The amount of calcium hypochlorite primarily determines the rate of reaction and heat generation. Appropriate emergency action and treatment for chlorine gas is discussed.

Adult↗