Chemical fingerprinting of naphthenic acids and oil sands process waters-A review of analytical methods for environmental samples.

This article provides a review of the routine methods currently utilized for total naphthenic acid analyses. There is a growing need to develop chemical methods that can selectively distinguish compounds found within industrially derived oil sands process affected waters (OSPW) from those derived from the natural weathering of oil sands deposits. Attention is thus given to the characterization of other OSPW components such as oil sands polar organic compounds, PAHs, and heavy metals along with characterization of chemical additives such as polyacrylamide polymers and trace levels of boron species. Environmental samples discussed cover the following matrices: OSPW containments, on-lease interceptor well systems, on- and off-lease groundwater, and river and lake surface waters. There are diverse ranges of methods available for analyses of total naphthenic acids. However, there is a need for inter-laboratory studies to compare their accuracy and precision for routine analyses. Recent advances in high- and medium-resolution mass spectrometry, concomitant with comprehensive mass spectrometry techniques following multi-dimensional chromatography or ion-mobility separations, have allowed for the speciation of monocarboxylic naphthenic acids along with a wide range of other species including humics. The distributions of oil sands polar organic compounds, particularly the sulphur containing species (i.e., OxS and OxS2) may allow for distinguishing sources of OSPW. The ratios of oxygen- (i.e., Ox) and nitrogen-containing species (i.e., NOx, and N2Ox) are useful for differentiating organic components derived from OSPW from natural components found within receiving waters. Synchronous fluorescence spectroscopy also provides a powerful screening technique capable of quickly detecting the presence of aromatic organic acids contained within oil sands naphthenic acid mixtures. Synchronous fluorescence spectroscopy provides diagnostic profiles for OSPW and potentially impacted groundwater that can be compared against reference groundwater and surface water samples. Novel applications of X-ray absorption near edge spectroscopy (XANES) are emerging for speciation of sulphur-containing species (both organic and inorganic components) as well as industrially derived boron-containing species. There is strong potential for an environmental forensics application of XANES for chemical fingerprinting of weathered sulphur-containing species and industrial additives in OSPW.

Treating juveniles in a sex offender program using adventure-based programming: a matched group design.

Ninety-five male juvenile sex offenders in an adventure-based behavior management program (LEGACY) were matched with male juveniles in state treatment-as-usual and other specialized programs in the same state to determine program effectiveness (as measured by rearrest rates). The LEGACY program demonstrated significant treatment effectiveness on rearrest rates when compared with youth development centers and other specialized programs two and three years later. Overall, three-year rearrest rates for the most serious reoffenses for each of the placements were as follows: 34.8% for YDC, 32.6% for OSP, and 19% for LEGACY.

Thiopyran route to polypropionates: exploiting and overcoming double stereodifferentiation and mutual kinetic enantioselection in aldol couplings of chiral fragments.

The aldol reaction of tetrahydro-4H-thiopyranone with 1,4-dioxa-8-thiaspiro[4.5]decane-6-carboxaldehyde (I) gives four possible diastereomeric adducts (II). Aldol reactions of I with each of the diastereomers of II and their corresponding methoxymethyl ethers III via the Ti enolates were investigated. Using racemic reactants, reactions with II proceeded with high levels of mutual kinetic enantioselection (MKE) and double stereodifferentiation (DS) to give one of the eight possible bisaldol adducts. Similar reactions of III proceeded with low levels of MKE and DS and gave two bisaldol adducts, one from each of the possible combinations of enantiomeric reactants. By extension, 11 of the 20 possible diastereomers of the bisaldol adduct could be obtained selectively. These adducts are useful for polypropionate synthesis.

Asymmetric synthesis of hexapropionate synthons by sequential enantiotopic group selective enolization of meso diketones.

Meso 1,9-diketones (six to seven stereocenters) are readily obtained by stepwise or simultaneous two-directional aldol reactions of tetrahydro-4H-thiopyran-4-one with a thiopyran-derived aldehyde or dialdehyde. Enantioselective enolizations of these diketones with the lithium amide from (R,R)-bis(1-phenylethyl)amine occur with simultaneous kinetic resolution to give the mono-TMS enol ethers in >90% yields (BORSM) and >95% ee. The products are applicable to polypropionate synthesis. [reaction: see text]

Exact morphometric modeling of rat lungs for predicting mechanical impedance.

We have developed a computational approach that allows for one-to-one mapping of the airway anatomy when predicting the overall lung mechanical properties and their response to explicit constriction patterns imposed on the airway tree. Specifically, we have exploited the database from Raabe et al. (LF-53 Albuquerque, NM: Lovelace foundation for radical Education and Research), to build the first anatomically based computational model of the rat. The model was then used to predict the response to homogeneous and heterogeneous peripheral airway constriction. Unlike in humans, the inherent asymmetry in the airway tree of rats is predicted to be a dominant contributor to the frequency dependence of lung resistance and elastance even if the constriction is imposed homogeneously. A similar approach would, in principal, be applicable for humans, but the Raabe data is not sufficiently complete to permit this.

Airway remodeling in asthma amplifies heterogeneities in smooth muscle shortening causing hyperresponsiveness.

Although airway remodeling and inflammation in asthma can amplify the constriction response of a single airway, their influence on the structural changes in the whole airway network is unknown. We present a morphometric model of the human lung that incorporates cross-sectional wall areas corresponding to the adventitia, airway smooth muscle (ASM), and mucosa for healthy and mildly and severely asthmatic airways and the influence of parenchymal tethering. A heterogeneous ASM percent shortening stimulus is imposed, causing distinct constriction patterns for healthy and asthmatic airways. We calculate lung resistance and elastance from 0.1 to 5 Hz. We show that, for a given ASM stimulus, the distribution of wall area in asthmatic subjects will amplify not only the mean but the heterogeneity of constriction in the lung periphery. Moreover, heterogeneous ASM shortening that would produce only mild changes in the healthy lung can cause hyperresponsive changes in lung resistance and elastance at typical breathing rates in the asthmatic lung, even with relatively small increases in airway resistance. This condition arises when airway closures occur randomly in the lung periphery. We suggest that heterogeneity is a crucial determinant of hyperresponsiveness in asthma and that acute asthma is more a consequence of extensive airway wall inflammation and remodeling, predisposing the lung to produce an acute pattern of heterogeneous constriction.

How heterogeneous bronchoconstriction affects ventilation distribution in human lungs: a morphometric model.

Convective dependent flow heterogeneities associated with airways proximal to the acini are the dominant cause of abnormal ventilation distribution during induced bronchoconstriction (Verbanck, S., D. Schuermans, A. Van Muylem, M. Paira, M. Noppen, and W. Vincken. Ventilation distribution during histamine provocation. J. Appl. Physiol. 83:1907-1916, 1997). We applied a morphometric model of the human lung to predict flow distributions among the acini during heterogeneous bronchoconstriction and relate these distributions to impairments in the mechanical properties of the lung. The model has an asymmetrical branching airway system. Heterogeneous constriction was invoked by defining an airway constriction distribution with a mean (mu) and coefficient of variation (CV) and either a Gaussian or log normal distribution. The lung resistance (RL) and elastance (EL) were most sensitive to severely heterogeneous constriction that produced a few highly constricted or closed airways dispersed randomly throughout the periphery. Ventilation distribution in the healthy lung was effectively homogeneous over the frequency range of 0.1-5.0 Hz. With homogeneous or mildly heterogeneous constriction (CV< or =20%) ventilation remained fairly homogeneous at low frequencies (< or =0.1 Hz) but rapidly became heterogeneous as frequency increased. Conversely, a low mean but severely heterogeneous constriction that produced random airway closure produced abnormal ventilation distribution in most acini at all frequencies, and some acini received up to 25 times the normal ventilation. This suggests that certain forms of heterogeneity can lead to shear induced lung injury even at common mechanical ventilation rates.

Relationship between heterogeneous changes in airway morphometry and lung resistance and elastance.

We present a dog lung model to predict the relation between inhomogeneous changes in airway morphometry and lung resistance (RL) and elastance (EL) for frequencies surrounding typical breathing rates. The RL and EL were sensitive in distinct ways to two forms of peripheral constriction. First, when there is a large and homogeneous constriction, the RL increases uniformly over the frequency range. The EL is rather unaffected below 1 Hz but then increases with frequencies up to 5 Hz. This increase is caused by central airway wall shunting. Second, the RL and EL are extremely sensitive to mild inhomogeneous constriction in which a few highly constricted or nearly closed airways occur randomly throughout the periphery. This results in extreme increases in the levels and frequency dependence of RL and EL but predominantly at typical breathing rates (<1 Hz). Conversely, the RL and EL are insensitive to highly inhomogeneous airway constriction that does not produce any nearly closed airways. Similarly, alterations in the RL and EL due to central airway wall shunting are not likely until the preponderance of the periphery constricts substantially. The RL and EL spectra are far more sensitive to these two forms of peripheral constriction than to constriction conditions known to occur in the central airways. On the basis of these simulations, we derived a set of qualitative criteria to infer airway constriction conditions from RL and EL spectra.

Applications of S-layers.

The wealth of information existing on the general principle of S-layers has revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) functional groups on the surface and in the pores are aligned in well-defined positions and orientations and accessible for binding functional molecules in very precise fashion; (iii) isolated S-layer subunits from many organisms are capable of recrystallizing as closed monolayers onto solid supports at the air-water interface, on lipid monolayers or onto the surface of liposomes. Particularly their repetitive physicochemical properties down to the subnanometer scale make S-layers unique structures for functionalization of surfaces and interfaces down to the ultimate resolution limit. The following review focuses on selected applications in biotechnology, diagnostics, vaccine development, biomimetic membranes, supramolecular engineering and nanotechnology. Despite progress in the characterization of S-layers and the exploitation of S-layers for the applications described in this chapter, it is clear that the field lags behind others (e.g. enzyme engineering) in applying recent advances in protein engineering. Genetic modification and targeted chemical modification would allow several possibilities including the manipulation of pore permeation properties, the introduction of switches to open and close the pores, and the covalent attachment to surfaces or other macromolecules through defined sites on the S-layer protein. The application of protein engineering to S-layers will require the development of straightforward expression systems, the development of simple assays for assembly and function that are suitable for the rapid screening of numerous mutants and the acquisition of structural information at atomic resolution. Attention should be given to these areas in the coming years.