A new Raman-based apparatus for proximal detection of energetic materials on people, was developed and tested for the first time. All the optical and optoelectronics components of the apparatus, as well as their optical matching, were carefully chosen and designed to respect international eye-safety regulations. In this way, the apparatus is suitable for civil applications on people in public a...

The unique capability of secondary electrospray ionization (SESI) as a nonradioactive ionization source to detect analytes in both liquid and gaseous samples was evaluated using aqueous solutions of three common military explosives: cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), nitroglycerin (NG) and pentaerythritol tetranitrate (PETN). The adducts formed between the compounds and their re...

Terahertz range of electromagnetic spectrum (0.1 ÷ 10) THz has focused attention of scientists for years because of many interesting features including existence of spectral fingerprints of many materials (also explosives), through clothing imaging and safety for human being. Such advantages are of great importance for biochemical, defense and security related applications. Scanning of pure exp...

Large-scale molecular dynamics simulations and the reactive force field ReaxFF were used to study shock-induced initiation in crystalline pentaerythritol tetranitrate (PETN). In the calculations, a PETN single crystal was impacted against a wall, driving a shockwave back through the crystal in the [100] direction. Two impact speeds (4 and 3 km/s) were used to compare strong and moderate shock b...

This work investigates the stability of trace (tens of nanograms) deposits of six explosives: erythritol tetranitrate (ETN), pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitramine (HMX), 2,4,6-trinitrotoluene (TNT), and 2,4,6-trinitrophenylmethylnitramine (tetryl) to determine environmental stabilities and lifetimes of trace level materials. ...

Hybrid functional theory is applied for calculation of band gaps in the molecular crystals anthracene, pentaerythritol (PE), pentaerythritol tetranitrate (PETN), and cyclotrimethylene trinitramine (RDX). The B3LYP hybrid functional is observed to produce band gap estimates in reasonable agreement with experiment for anthracene and RDX. This approach, which has been successfully used recently fo...

Luminescent silicon nanocrystals (Si-NCs) surface functionalized with dodecyl groups were exposed to solutions of nitroaromatic compounds including nitrobenzene, nitrotoluene, and dinitrotoluene. It was found that Si-NC luminescence was quenched upon exposure to nitroaromatics via an electron transfer mechanism as indicated by Stern-Volmer analysis. This quenching was exploited and a straightfo...

We investigated the conservation and antibody accessibility of inner core epitopes of Neisseria meningitidis lipopolysaccharide (LPS) because of their potential as vaccine candidates. An immunoglobulin G3 murine monoclonal antibody (MAb), designated MAb B5, was obtained by immunizing mice with a galE mutant of N. meningitidis H44/76 (B. 15.P1.7,16 immunotype L3). We have shown that MAb B5 can b...

Shigella flexneri is the major pathogen causing bacillary dysentery in developing countries. S. flexneri is divided into at least 16 serotypes based on the combination of antigenic determinants present in the O-antigen. All the serotypes (except for serotype 6) share a basic O-unit containing one N-acetyl-d-glucosamine and three l-rhamnose residues, whereas differences between the serotypes are...

A mixture of explosives was analyzed by gas chromatography (GC) linked to ultraviolet (UV) spectrophotometry that enabled detection in the range of 178-330 nm. The gas-phase UV spectra of 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), ethylene glycol dinitrate (EGDN), glycerine trinitrate (NG, nitroglycerine), triacetone triperoxide (TATP), and pentaerythritol tetranitrate (PETN) were s...