On the selection of measures of distance between probability distributions

A notion of relative strength and weakness is defined for the comparison of measures of distance between probability distributions and is shown to be appropriate for use in the selection of distances as quasioptimal design criteria in problems such as signal selection and detector design when the preferred criteria, probability of error and asymptotic relative efficiency, are intractable. Csiszar's work on the topological properties of ?-divergences, a class of distances also investigated by Ali and Silvey, enables one to identify strong distances and provides a justification for the experimental findings of previous investigators.     

Hydrogen production and consumption of organic acids by a phototrophic microbial consortium

Alternative fuel sources have been extensively studied. Hydrogen gas has gained attention because its combustion releases only water, and it can be produced by microorganisms using organic acids as substrates. The aim of this study was to enrich a microbial consortium of photosynthetic purple non-sulfur bacteria from an Upflow Anaerobic Sludge Blanket reactor (UASB) using malate as carbon source. After the enrichment phase, other carbon sources were tested, such as acetate (30 mmol l⁻¹), butyrate (17 mmol l⁻¹), citrate (11 mmol l⁻¹), lactate (23 mmol l⁻¹) and malate (14.5 mmol l⁻¹). The reactors were incubated at 30 °C under constant illumination by 3 fluorescent lamps (81 μmol m⁻² s⁻¹). The cumulative hydrogen production was 7.8, 9.0, 7.9, 5.6 and 13.9 mmol H₂ l⁻¹ culture for acetate, butyrate, citrate, lactate and malate, respectively. The maximum hydrogen yield was 0.6, 1.4, 0.7, 0.5 and 0.9 mmol H₂ mmol⁻¹ substrate for acetate, butyrate, citrate, lactate and malate, respectively. The consumption of substrates was 43% for acetate, 37% for butyrate, 100% for citrate, 49% for lactate and 100% for malate. Approximately 26% of the clones obtained from the Phototrophic Hydrogen-Producing Bacterial Consortium (PHPBC) were similar to Rhodobacter, Rhodospirillum and Rhodopseudomonas, which have been widely cited in studies of photobiological hydrogen production. Clones similar to the genus Sulfurospirillum (29% of the total) were also found in the microbial consortium.     

Co-control of urban air pollutants and greenhouse gases in Mexico City

This study addresses the synergies of mitigation measures to control urban air pollutant and greenhouse gas (GHG) emissions, in developing integrated "co-control" strategies for Mexico City. First, existing studies of emissions reduction measures--PROAIRE (the air quality plan for Mexico City) and separate GHG studies--are used to construct a harmonized database of options. Second, linear programming (LP) is developed and applied as a decision-support tool to analyze least-cost strategies for meeting co-control targets for multiple pollutants. We estimate that implementing PROAIRE measures as planned will reduce 3.1% of the 2010 metropolitan CO2 emissions, in addition to substantial local air pollutant reductions. Applying the LP, PROAIRE emissions reductions can be met at a 20% lower cost, using only the PROAIRE measures, by adjusting investments toward the more cost-effective measures; lower net costs are possible by including cost-saving GHG mitigation measures, but with increased investment. When CO2 emission reduction targets are added to PROAIRE targets, the most cost-effective solutions use PROAIRE measures for the majority of local pollutant reductions, and GHG measures for additional CO2 control. Because of synergies, the integrated planning of urban-global co-control can be beneficial, but we estimate that for Mexico City these benefits are often small.     

Survey of authenticity of meat species in food products subjected to different technological processes,by means of PCR-RFLP analysis

Polymerase chain reaction (PCR) coupled to restriction-fragment length polymorphism analysis (RFLP) was considered for exploring the incidence of incorrect labelling in food products containing one or more meat species. Universal primers CYT b1/CYT b2, which amplify a variable region of the mitochondrial cytochrome b of vertebrates, and endonucleases PalI, MboI, HinfI and AluI were used for this purpose. Fifty food products, nine of them raw or cured and the other 41 subjected to a variety of technological processes such as pre-cooking and freezing, cooking and smoking, dehydration or sterilisation, were investigated. Twenty of the 50 products declared mixtures of meat species on their labels. Fifteen (30%) of the 50 food samples investigated displayed an incorrect qualitative labelling. While this affected only one (11.1%) of the nine raw/cured products, 14 (34.2%) of the 41 products subjected to some type of heat-processing were not correctly labelled. The undeclared presence of turkey was the most frequent concern, since it was detected in seven food products. The complete absence of a declared species of high commercial value—such as beef or roe-deer—was observed in another four cases. The PCR-RFLP method used here proved to be a rapid and easy-to-perform two-step analytical approach to achieve qualitative meat species identification in raw and cooked food products containing one or more different species.     

Metabolism of BTEX and naphtha compounds to methane in oil sands tailings

Naphtha, comprising low molecular weight aliphatics and aromatics (C3-C14), is used as a diluent in processing of bitumen from oil sands. A small fraction (<1%) is lost to tailings waste and incorporated into mature fine tailings (MFT). BTEX (benzene, toluene, ethylbenzene, and xylenes) and whole naphtha were assessed for biodegradation under methanogenic conditions using MFT from an oil sands tailings settling basin. MFT spiked with 0.05-0.1% w/v of BTEX compounds produced up to 2.1 (+/-0.1) mmol of methane during 36 weeks of incubation. Metabolism of 0.5-1.0% w/v naphtha in MFT yielded up to 5.7 (+/-0.2) mmol of methane during 46 weeks of incubation. Gas chromatographic analyses showed that BTEX degraded in the sequence: toluene > o-xylene > m- plus p-xylene > ethylbenzene > benzene. Only 15-23% of whole naphtha, mainly n-alkanes (in the sequence: nonane > octane > heptane) and some BTEX compounds (toluene > o-xylene > m-xylene), was metabolized. Other naphtha constituents, such as iso-paraffins and naphthenes, remained unchanged during this period. These results suggest that the microbial communities in the MFT can readily utilize certain fractions of unrecovered naphtha in oil sands tailings and support methanogenesis in settling basins. Current study findings could influence extraction process, MFT management, and reclamation options.     

Cationic copolymerization of phenyl glycidyl ether with lactones. Characterization of the reaction mixture with chromatographic methods

This paper refers to the influence of the catalysts boron trifluoride p-methoxyaniline complex (BF₃ · MA) and boron trifluoride etherate complex (BF₃ · Et₂O) having different reactivity in cationic copolymerization of phenyl glycidyl ether (PGE) with γ-butyrolactone (γ-BL) and ϵ-caprolactone (ϵ-CL), respectively. Reactions were followed by FT-IR, HPLC and SEC. SEC with multiple detection and Two-Dimensional-Chromatography HPLC/SEC were used to characterize the products in view to their copolymer compositions. In the presence of BF₃ · MA a preferred formation of spiroorthoesters (SOE) was observed; the polymerization of SOE under these conditions can be neglected. In case of the more reactive BF₃ · Et₂O the epoxide homopolymerization strongly competes with SOE formation, resulting in a product mixture of epoxide homopolymers (and in the case of ϵ-CL also lactone homopolymers) and copolymers with low lactone content.     

Wet‐Route Synthesis and Characterization of Yb:CaF2 Optical Ceramics

This paper reports a new strainless fabrication method for ytterbium‐doped CaF₂ laser ceramics involving no drying step before green body casting. The nanoparticles were kept in aqueous solution until green body shaping. Centrifugation was used to obtain correct compactness of the green body before sintering. Characterizations were conducted at different steps of the fabrication process. No grain boundaries oxidation was observed in the sintered ceramics although the nanoparticles were permanently maintained in water until they were sintered. Finally, these ceramics are more homogeneous and have less light scattering defects (no porosity), and present improved optical properties when compared to ceramics obtained from dried nanopowders.     

FATIGUE CRACK GROWTH BEHAVIOUR IN MOLTEN-METAL PROCESSED Sic PARTICLE-REINFORCED ALUMINIUM ALLOYS

Fatigue crack initiation and subsequent short crack growth behaviour of 2014-5wt%SiC aluminium alloy composites has been examined in 4-point bend loading using smooth bar specimens. The growth rates of long fatigue cracks have also been measured at different stress ratios using pre-cracked specimens. The distributions of Sic particles and of coarse constituent particles in the matrix (which arise as a result of the molten-metal processing and relatively slow cooling rate) have been investigated. Preferential crack initiation sites were found to be Sic-matrix interfaces, Sic particles associated with constituent particles and the coarse constituent particles themselves. For microstructurally short cracks the dispersed SiC particles also act as temporary crack arresters. In the long crack growth tests, higher fatigue crack growth rates were obtained than for monolithic alloys. This effect is attributed to the contribution of void formation, due to the decohesion of Sic particles, to the fatigue crack growth process in the composite. Above crack depths of about 200 μm “short” crack growth rates were in good agreement with the long crack data, showing a Paris exponent, m= 4 in both cases. For the long crack and short crack growth tests little effect of specimen orientation and grain size was observed on fatigue crack growth rates, but, specimen orientation affected the toughness. No effect of stress ratio in the range R=0.2-0.5 was seen for long crack data in the Paris region.     

High-performance Li-S battery cathode with catalyst-like carbon nanotube-MoP promoting polysulfide redox

Despite promising characteristics such as high specific energy and low cost,current Li-S batteries fall short in cycle life.Improving the cycling stability of S cathodes requires immobilizing the lithium polysulfide (LPS) intermediates as well as accelerating their redox kinetics.Although many materials have been explored for trapping LPS,the ability to promote LPS redox has attracted much less attention.Here,we report for the first time on transition metal phosphides as effective host materials to enhance both LPS adsorption and redox.Integrating MoP-nanoparticle-decorated carbon nanotubes with S deposited on graphene oxide,we enable Li-S battery cathodes with substantially improved cycling stability and rate capability.Capacity decay rates as low as 0.017％ per cycle over 1,000 cycles can be realized.Stable and high areal capacity (＞ 3 mAh·cm-2) can be achieved under high mass loading conditions.Comparable electrochemical performance can also be achieved with analogous material structures based on CoP,demonstrating the potential of metal phosphides for long-cycle Li-S batteries.     

Development and in vitro characterization of self-emulsifying drug delivery system (SEDDS) for oral opioid peptide delivery

Aim: In this study, self-emulsifying drug delivery system (SEDDS) for oral delivery of opioid peptide dalargin were developed and characterized in vitro.

Methods: Dalargin lipophilicity was increased by O-esterification of tyrosine OH group, hydrophobic ion pairing, or a combination thereof. Distribution coefficients (log?D) of lipidized dalargin derivatives were determined. Then, dalargin was incorporated in chosen SEDDS, namely SEDDS-1, composed of 50% Capmul 907, 40% Cremophor EL, and 10% propylene glycol and comparatively more lipophilic SEDDS-2 composed of 30% Captex 8000, 30% Capmul MCM, 30% Cremophor EL, and 10% propylene glycol. Additionally, SEDDS were characterized regarding droplet size, polydispersity index (PDI), cloudy point, physical stability and stability against pancreatic lipase. Furthermore, mucus permeating properties of SEDDS and their ability to protect the incorporated dalargin against proteolysis by trypsin, α-chymotrypsin, elastase, simulated gastric fluid (SGF), and simulated intestinal fluid (SIF) were evaluated.

Results: The highest dalargin drug payload of 4.57% in SEDDS-2 was achieved when dalargin palmitate (pDAL) was ion paired with sodium dodecyl sulfate (SDS) in molar ratio 1:1. Moreover, SEDDS-1 and SEDDS-2 had a narrow droplet size distribution with average droplet sizes of 42.1 and 33.1?nm with PDI of 0.042 and 0.034, respectively. Lipolysis study showed that within 30?min 78.5% of SEDDS-1 and 92.1% of SEDDS-2 were digested. In addition, both SEDDS exhibited mucus permeating properties as well as a protective effect against enzymatic degradation by trypsin, α-chymotrypsin, elastase, SGF and SIF.

Conclusion: The results of this study suggest that the developed SEDDS could be considered for oral opioid peptide delivery.