An investigation into the effect of surveillance drones on textile evidence at crime scenes

With increasing numbers of Police forces using drones for crime scene surveillance, the effect of the drones on trace evidence present needs evaluation. In this investigation the effect of flying a quadcopter drone at different heights over a controlled scene and taking off at different distances from the scene were measured. Yarn was placed on a range of floor surfaces and the number lost or moved from their original position was recorded.It was possible to estimate "safe" distances above and take off distance from the bath mat (2. m and 1. m respectively), and carpet tile (3. m and 1. m) which were the roughest surfaces. The maximum distances tested of 5. m above and 2. m from was not far enough to prevent significant disturbance with the other floor surfaces. This report illustrates the importance of considering the impact of new technologies into a forensic workflow on established forensic evidence prior to implementation

Detection and mapping of Cannabinoids in single hair samples through rapid derivatization- Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

The sample preparation method reported in this work has permitted for the first time the application of Matrix Assisted Laser Desorption Ionization Mass Spectrometry Profiling and Imaging (MALDI-MSP and MALDI-MSI) for the detection and mapping of cannabinoids in a single hair sample. MALDI-MSI analysis of hair samples has recently been suggested as an alternative technique to traditional methods of GC-MS and LC-MS due to simpler sample preparation, the ability to detect a narrower time frame of drug use and a reduction in sample amount required. However, despite cannabis being the most commonly used illicit drug worldwide, a MALDI-MS method for the detection and mapping of cannabinoids in a single hair has not been reported. This is probably due to the poor ionization efficiency of the drug and its metabolites and low concentration incorporated into hair. This research showed that the in situ derivatization of cannabinoids through addition of an N-methylpyridium group resulted in improved ionization efficiency, permitting both detection and mapping of Δ9-tetrahydrocannabinol (THC), Cannabinol (CBN), cannabidiol (CBD) and the metabolites 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH), 11-Hydroxy-delta-9-tetrahydrocannabinol (11-OH-THC) and 11-nor-delta(9)-carboxy-tetrahydrocannabinol glucuronide (THC-COO-glu). Additionally, for the first time an in-source re-arrangement of THC was observed and characterised in this paper thus contributing to new and accurate knowledge in the analysis of this drug by MALDI mass spectrometry

Encouraging innovation

The second annual report of the Government Chief Scientific Adviser (GCSA), Sir Mark Walport, looks at the power of forensic science and its many applications. The report draws on evidence provided by experts in several fields. It covers the use of forensic analysis within the criminal justice system through to the prevention, deterrence and detection of fraudulent products and services

<i>N,N</i>-bis-(dimethylfluorosilylmethyl)amides of <i>N</i>-organosulfonylproline and sarcosine: synthesis, structure, stereodynamic behaviour and <i>in silico</i> studies

(O→Si)-Chelate difluorides R3R2NCH(R1)C(O)N(CH2SiMe2F)2 (9a–c, R1R2 = (CH2)3, R3 = Ms (a), Ts (b); R1 = H, R2 = Me, R3 = Ms (c)), containing one penta- and one tetracoordinate silicon atoms were synthesized by silylmethylation of amides R3R2NCH(R1)C(O)NH2, subsequent hydrolysis of unstable intermediates R3R2NCH(R1)C(O)N(CH2SiMe2Cl)2 (7a–c) into 4-acyl-2,6-disilamorpholines R3R2NCH(R1)C(O)N(CH2SiMe2O)2 (8a–c) and the reaction of the latter compounds with BF3·Et2O. The structures of disilamorpholines 8a,c and difluoride 9a were confirmed by an X-ray diffraction study. According to the IR and NMR data, the O→Si coordination in solutions of these compounds was weaker than that in the solid state due to effective solvation of the Si–F bond. A permutational isomerisation involving an exchange of equatorial Me groups at the pentacoordinate Si atom in complexes 9a–c was detected, and its activational parameters were determined by 1H DNMR. In silico estimation of possible pharmacological effects and acute rat toxicity by PASS Online and GUSAR Online services showed a potential for their further pharmacological study

Perceptions of a program approach to virtual laboratory provision for analytical and bioanalytical sciences

When teaching chemistry and biosciences courses to undergraduate and postgraduate students, laboratory experience is a crucial requirement for skills development. Due to COVID-19 related closure of laboratories it became critical to replace that experience with virtual delivery. Through carefully designed learning experiences it is possible for students to gain skills such as experimental design, problem solving, record keeping and data analysis. Here we present a coordinated approach to the design of laboratory classes for a cross discipline postgraduate program. Virtual laboratory classes, using freely available web-based simulators, were run in a synchronous manner with pre lab briefing and post lab data analysis sessions. The laboratory scripts were developed using a command prompt design: [Do][Explore][Act] framework, which is intended to provide students with a guided approach to using the simulator while in a remote setting. The intended outcome was to develop student’s record keeping and understanding of the scientific principles of the instrumentation through practical experimentation. Student experience of the virtual laboratory provision was surveyed via a mix method approach, with an 81% response rate. Satisfaction with the virtual labs was high (68%), with students agreeing the laboratories contained the appropriate balance of challenge and support. The command prompts were thought to be a very useful way to structure a lab script (77% agreement) and many suggested this approach should be kept for future laboratory use. Students self-identified the main skills learnt as being laboratory bookkeeping, analyzing data, problem solving and use of equipment

Self-Lubricating Nano-Ball-Bearings

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55898/1/82_ftp.pd

Self-assembly of fluoride-encapsulated polyhedral oligomeric silsesquioxane (POSS) nanocrystals

The self-assembly and crystal packing of a unique series of nanocrystalline fluoride ion-encapsulated polyhedral oligomeric silsesquioxane compounds (F-POSS), with substituted electron-withdrawing group (EWG) perfluorinated alkyl chain arms of varying lengths was investigated. The fluorine-encapsulated T8[(CH2)n-EWG]8F--18-crown-6-ether-M+ and T8[(CH2)n-EWG]8F--tetrabutyl ammonium TBA+ compounds with fluorinated alkyl chain arms, were synthesized and subsequently analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and simultaneous small- and wide-angle X-ray scattering SAXS/WAXS techniques. DSC and TGA of the compounds showed that the melting temperatures occurred below 100 °C and were thermally stable above their melting temperatures. SAXS/WAXS data probed the crystalline structure and self-assembly of the nanocrystalline compounds. At ambient temperatures, the crystalline structures of the compounds were seen to be complex with triclinic unit cells. On cooling from the melt, the self-assembly of the compounds with shorter fluorinated alkyl chain arms is dominated by the ionic attraction between the cages such that the arms form a disordered state that only reorder on standing. In contrast, the self-assembly of the compounds with longer fluorinated alkyl chain arms is dominated by the alignment of the arms into rod-like morphologies such that a fully ordered solid is formed from the melt. Electrical characterization has revealed that the POSS cages exhibited an insulating behavior. The POSS cages with or without fluoride ion encapsulation had similar AC conductivities but cages without fluoride ion encapsulation have the highest relative permittivity. The results show that due to the inorganic-organic-ionic nature the F-POSS ion encapsulated compounds and nanocrystalline self-assembly, they have great potential as interfacial compatibilizers enhancing miscibility of polymer composites and aiding interactions between polar and non-polar solvents as ionic liquids

Spontaneous assembly of chemically encoded two-dimensional coacervate droplet arrays by acoustic wave patterning

The spontaneous assembly of chemically encoded, molecularly crowded, water-rich micro-droplets into periodic defect-free two-dimensional arrays is achieved in aqueous media by a combination of an acoustic standing wave pressure field and in situ complex coacervation. Acoustically mediated coalescence of primary droplets generates single-droplet per node micro-arrays that exhibit variable surface-attachment properties, spontaneously uptake dyes, enzymes and particles, and display spatial and time-dependent fluorescence outputs when exposed to a reactant diffusion gradient. In addition, coacervate droplet arrays exhibiting dynamical behaviour and exchange of matter are prepared by inhibiting coalescence to produce acoustically trapped lattices of droplet clusters that display fast and reversible changes in shape and spatial configuration in direct response to modulations in the acoustic frequencies and fields. Our results offer a novel route to the design and construction of ‘water-in-water' micro-droplet arrays with controllable spatial organization, programmable signalling pathways and higher order collective behaviour

Completely discontinuous organic/ inorganic hybrid nanocomposites by self-curing of nanobuilding blocks constructed from reactions of [HMe 2 SiOSiO 1.5 ] 8 with vinylcyclohexene

The reaction of 4-vinyl-1-cylcohexene with [HMe 2 SiOSiO 1.5 ] 8 provides tetra- and octa-2-cyclohexenylethyloctasilsesquioxanes. The tetrabifunctional [cyclohexenylethylMe 2 SiOSiO 1.5 ] 4 -[HMe 2 SiOSiO 1.5 ] 4 (average degree of functionalization) melts near 80 °C and can be cast and then cured (by thermal hydrosilylation) into transparent nanocomposite shapes. These materials, while not nanoporous, offer dielectric constants of 2.8–2.9 at 100 kHz to 3 MHz, and are air stable to temperatures ≥ 400 °C. The resulting materials appear (by X-ray diffraction) to be partially ordered after curing. The octafunctional material also melts at low temperatures ( ca 120 °C) and can be copolymerized with hydridosiloxanes to give similar materials with lower thermal stability. The synthesis and characterization of the starting materials is described, as well as thermal curing studies and properties characterization of the resultant nanocomposites. Copyright © 2007 Society of Chemical IndustryPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57384/1/2281_ftp.pd