Combining the tape-lift method and Fourier transform infrared spectroscopic imaging for forensic applications

Conventional Fourier transform infrared (FT-IR) spectroscopy and microscopy have been widely used in forensic science. New opportunities exist to obtain chemical images and to enhance the spatial resolution using attenuated total reflection (ATR) FT-IR spectroscopy coupled with a focal-plane array (FPA) detector. In this paper, the sensitivity limits of FT-IR imaging using three different ATR crystals (Ge, ZnSe, and diamond) in three different optical arrangements for the detection of model particles is discussed. Model systems of ibuprofen and paracetamol particles having sizes below 32 mum were studied. The collection of drug particles was achieved with the aid of two different tapes: common adhesive tape and a film of polydimethylsiloxane (PDMS). The surface of the film with collected particles was measured directly via ATR-FT-IR imaging. Since the removal of tape from porous surfaces can be difficult, the application of micro ATR-FT-IR imaging directly to the surface of a newspaper contaminated with particles of model drugs is also discussed. In order to assess the feasibility of the chosen method in a forensic case study, the detection of diacetylmorphine hydrochloride traces in PDMS matrix and the finger surface is investigated. The scenarios considered were that of the detection of evidence collected at a crime scene with the tape lift method and the analysis of the finger of an individual after drug handling. The results show broad implications in the detection of drugs of abuse.     

Visual evaluation of cattle cleanliness and correlation to carcass microbial contamination during slaughtering

The aim of the study was to establish whether the visual cleanliness of cattle slaughtered was correlated to hide and carcass contamination as indicated by aerobic colony count (ACC), Enterobacteriaceae count (EC) and Escherichia coli count (ECC). Cattle in a slaughterhouse were visually inspected and assigned to a category from 1 (very clean) to 5 (very dirty) based on cleanliness. Fifteen animals for each category were randomly selected, hide and carcass sampled and analyzed for ACC, EC and ECC. Results showed that increasing dirt on cattle was associated with higher ACC, EC and ECC on hide and carcasses. Carcass ACC and ECC belonging to animals classified in cleanliness categories 3, 4 or 5 have a higher probability of exceeding the limits set by the Reg. EU 2073/2005. The study supports the conclusion that the pre-slaughter visual evaluation of animal cleanliness and application of corrective actions can be an effective aid to reduce carcass contamination.     

Organochlorine compounds in Lake Superior: chiral polychlorinated biphenyls and biotransformation in the aquatic food web

The enantiomeric composition of seven chiral PCB congeners was measured in the Lake Superior aquatic food web sampled in 1998, to determine the extent of enantioselective biotransformation in aquatic biota. All chiral PCB congeners studied (CBs 91, 95, 136, 149, 174, 176, and 183) biomagnified in the Lake Superior aquatic food web, based on biomagnification and food web magnification factors greater than unity. PCB atropisomers were racemic in phytoplankton and zooplankton, suggesting no biotransformation potential toward PCBs for these low trophic level organisms. However, Diporeia and mysids had significantly nonracemic residues for most chiral congeners studied. This observation suggests that these macrozooplankton can stereoselectively metabolize chiral congeners. Alternatively, macrozooplankton obtained nonracemic residues from feeding on organic-rich suspended particles and sediments, which would imply that stereoselective microbial PCB biotransformation may be occurring in Lake Superior sediments at PCB concentrations far lower than that previously associated with such activity. Widely nonracemic PCB residues in forage fish (lake herring, rainbow smelt, and slimy sculpin) and lake trout suggest a combination of both in vivo biotransformation and uptake of nonracemic residues from prey for these species. Minimum biotransformation rates, calculated from enantiomer mass balances between predators and prey, suggest metabolic half-lives on the order of 8 yr for CB 136 in lake trout and 2.6 yr for CB 95 in sculpins. This result suggests that significant biotransformation may occur for metabolizable PCB congeners over the lifespan of these biota. This study highlights the potential of chiral analysis to study biotransformation processes in food webs.     

Antibacterial agents and cystic fibrosis: synthesis and antimicrobial evaluation of a series of N-thiomethylazetidinones

The increasing emergence of multidrug-resistant microorganisms is one of the greatest challenges in the clinical management of infectious disease. New antimicrobial agents are therefore urgently required, particularly in the treatment of chronic and recurrent infections often associated with antibiotic-resistant pathogens, as in the case of cystic fibrosis (CF) patients. This study reports the antibacterial activity of a series of monocyclic β-lactams with an alkylidenecarboxyl chain or electron-withdrawing groups such as 4-OAc, 4-SAc, and 4-SO(2)Ph at the C4 position of the ring. N-Unsubstituted and N-thiomethyl derivatives were compared. A total of 33 azetidinones were tested for their activity against Gram-positive and Gram-negative bacterial clinical isolates. The combination of an N-thiomethyl group and a benzyl ester on the 4-alkylidene side chain were found to increase the potency against Gram-positive bacteria. The N-thiomethyl group clearly elevated the activity of 4-acetoxyazetidinones relative to the corresponding NH derivatives. The most active compounds showed minimum inhibitory concentration (MIC) values of 4 and 8 mg L(-1) against methicillin-resistant Staphylococcus aureus isolated from pediatric patients with CF.     

Easily accessible oxygen‐containing derivatives of niobium pentachloride as catalytic precursors for ethylene polymerization

The low catalytic activity of NbCl₅ as an ethylene polymerization catalyst was significantly increased by the addition of a series of oxygen donors. The novel niobium derivatives NbCl₅(OPh₂) (1), NbCl₅(OEt₂) (3), NbCl₅(O?CPh₂) (5), NbCl₅(O?CHPh) (6), NbCl₅(O?CHMe) (7) and [NbCl₄(dppe)₂](NbCl₆) (18) (dppe is 1,2‐bis(diphenylphosphino)ethane) and the previously reported derivatives NbCl₅(OMePh) (2), NbCl₅(thf) (4) (thf is tetrahydrofuran), NbCl₅(O?CHOMe) (8), NbCl₅(O?CHNMe₂) (9), NbCl₅[O?C(NMe₂)₂] (10), NbCl₅(NCMe) (11), NbCl₄(κ²‐1,2‐OC₆H₄OMe) (12), NbCl₄[κ²‐O?C(Me)CH₂C(Me₂)O] (13), (14), [NbCl₄(O₂CMe)]₂ (15), NbCl₃(dme)(µ‐O)NbCl₅ (16) (dme is 1,2‐dimethoxyethane), [NbCl₄(κ²‐dmm)₂](NbCl₆) (17) (dmm is dimethylmaleate), TaCl₅(O?CMe₂) (19) and [TaCl₄(O₂CMe)]₂ (20) were tested as catalytic precursors in the ethylene polymerization reaction using AlMe₃‐depleted methylaluminoxane as co‐catalyst. Highly linear polyethylene was obtained. Compounds 1, 3, 5, 6 and 8–13 showed catalytic activities in the range 89–116 kg_polymer mol_Nb^?1 h^?1 bar^?1, i.e. comparable with the best performances reached with niobium pre‐catalysts up to now. However, the dinuclear compounds 14–16 and 18 were found to be less active, whereas17 and the tantalum derivatives 19 and 20 did not produce polymer. Relatively high molecular weights were achieved with the mononuclear compounds 1, 2, 8, 9, 10 and 12, the dinuclear 16 and the phosphine ionic 18. Copyright © 2011 Society of Chemical Industry     

XPS and FT-IR investigation of silicate polymers

This article presents the results of an investigation of the compositional and structural features of an inorganic polymer synthesized from amorphous silica and KOH. The inorganic polymers were characterized using Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). FT-IR investigation of the inorganic polymers showed that an increase in the hydroxide concentration used in the synthesis shifts the position of the maximum absorbance of Si–O bands toward lower wave numbers, indicating the transformation of Q⁴ units to Q³ and Q² units. XPS investigation of the inorganic polymers showed that the total amount of oxygen and potassium present in the sample increased when higher concentrations of hydroxide were used in the synthesis. The O/Si ratio of the inorganic polymers changed from 2 to 2.6 when the KOH concentration was increased from 0.75 to 4 M. The increase in the O/Si ratio can be explained by the greater dissolution of SiO₂ particles leading to the formation of branched polymers and gelation.     

Investigating heavy metal resistance, bioaccumulation and metabolic profile of a metallophile microbial consortium native to an abandoned mine

Contaminated sites represent new ecological niches where historical pollution has originated an unusual microbial biodiversity. The knowledge of these microorganisms contributes to the discovery of new pathways and metabolic networks and may offer potential solutions for damaged areas. In the present work seven microbial consortia have been isolated from an abandoned mine of blend and galena (Ingurtosu, Italy) through a selection for resistance to zinc (tested up to 40 mM in solution). All the consortia were able to accumulate zinc and the best accumulator, named Ing5, has been studied for the following characteristics: resistance and accumulation of Zn, Cd, Hg, bioaccumulation mechanisms of Zn, and influence of Zn and Cd on the metabolic profile. The results indicate that the consortium Ing5 bears resistance systems for Cd and Hg as well as Zn and that, for some of the 5 isolates belonging to Ing5, the resistance thresholds are higher in consortium than in pure culture. The prevalent mechanism for zinc accumulation can be reasonably considered to be metabolism-dependent, inducible and regulated by metal concentrations. The study on the metabolic profile, carried out by the Biolog system, shows that Zn exerts a very low influence on the metabolic profile and that this influence can also be positive; Cd has a stronger negative influence but that, despite this, the consortium is able to maintain a wide metabolic potential in the presence of heavy metals. These features of Ing5 make it a good candidate for biotechnological applications and for further investigation of the degradation of organic pollutants in the presence of metals.     

Oil spill detection by satellite remote sensing

This paper presents the state of the art for oil spill detection in the world oceans. We discuss different satellite sensors and oil spill detectability under varying conditions. In particular, we concentrate on the use of manual and automatic approaches to discriminate between oil slicks and look-alikes based on pattern recognition. We conclude with a discussion of suggestions for further research with respect to oil spill detection systems.     

Issues and Implications of Deaf Culture in Therapy.

In the United States, it is estimated that between 200,000 and 500,000 individuals are culturally Deaf. Deaf culture provides unique challenges that can impact standard therapeutic techniques. Issues regarding the ability of hearing therapists to effectively work with Deaf clients are addressed, and a number of guidelines are offered to assist hearing therapists in bridging language barriers and cultural gaps with Deaf clients. Additionally, concerns about the selection and inclusion of sign language interpreters are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)