Absorption of gas into a wavy falling film

In this work, we present results of a study of gas absorption into a falling film on a vertical substrate. The film flow is accompanied by the formation of nonlinear waves which strongly influence the diffusion layer that develops from the film surface. As a result, significant enhancement of mass transfer has been observed in experiments. We use recent advances in modelling of the hydrodynamics and solve a two-dimensional convective-diffusion equation for the solute concentration. Numerical solutions for the finite-amplitude wave regimes and associated integral absorption rates are obtained for a range of flow conditions. Our results show clearly the influence of waves on the development of the diffusion layer and, in particular, the enhancement of absorption due to the waves; the existence of optimal conditions for maximizing the absorption rate is also demonstrated.     

NGF Enhances CGRP Release Evoked by Capsaicin from Rat Trigeminal Neurons: Differential Inhibition by SNAP-25-Cleaving Proteases

Nerve growth factor (NGF) is known to intensify pain in various ways, so perturbing pertinent effects without negating its essential influences on neuronal functions could help the search for much-needed analgesics. Towards this goal, cultured neurons from neonatal rat trigeminal ganglia—a locus for craniofacial sensory nerves—were used to examine how NGF affects the Ca²⁺-dependent release of a pain mediator, calcitonin gene-related peptide (CGRP), that is triggered by activating a key signal transducer, transient receptor potential vanilloid 1 (TRPV1) with capsaicin (CAP). Measurements utilised neurons fed with or deprived of NGF for 2 days. Acute re-introduction of NGF induced Ca²⁺-dependent CGRP exocytosis that was inhibited by botulinum neurotoxin type A (BoNT/A) or a chimera of/E and/A (/EA), which truncated SNAP-25 (synaptosomal-associated protein with Mr = 25 k) at distinct sites. NGF additionally caused a Ca²⁺-independent enhancement of the neuropeptide release evoked by low concentrations (<100 nM) of CAP, but only marginally increased the peak response to ≥100 nM. Notably, BoNT/A inhibited CGRP exocytosis evoked by low but not high CAP concentrations, whereas/EA effectively reduced responses up to 1 µM CAP and inhibited to a greater extent its enhancement by NGF. In addition to establishing that sensitisation of sensory neurons to CAP by NGF is dependent on SNARE-mediated membrane fusion, insights were gleaned into the differential ability of two regions in the C-terminus of SNAP-25 (181–197 and 198–206) to support CAP-evoked Ca²⁺-dependent exocytosis at different intensities of stimulation.     

A Symmetrical Diester as the Sex Attractant Pheromone of the North American Click Beetle Parallelostethus attenuatus (Say) (Coleoptera: Elateridae)

Hexanoic acid, 1-octanol, 1,8-octanediol, octyl hexanoate, 1,8-octanediol monohexanoate, and 1,8-octanediol dihexanoate were identified in headspace volatiles collected from the crushed abdomen of a female click beetle of the species Parallelostethus attenuatus (Say) (Elaterinae, tribe Elaterini). In field trials carried out in Illinois, South Carolina, North Carolina, and Virginia, adult male beetles were strongly attracted to 1,8-octanediol dihexanoate alone. Blends of the dihexanoate with one or more of the other compounds proved to be less attractive than the dihexanoate alone, suggesting that the pheromone of this species may consist of a single compound. The symmetrical diester structure of the pheromone is a novel natural product and appears to be structurally unique among insect pheromones.

     

Structure-activity relationship for the first-in-class clinical steroid sulfatase inhibitor Irosustat (STX64, BN83495)

Structure–activity relationship studies were conducted on Irosustat (STX64, BN83495), the first steroid sulfatase (STS) inhibitor to enter diverse clinical trials for patients with advanced hormone‐dependent cancer. The size of its aliphatic ring was expanded; its sulfamate group was N,N‐dimethylated, relocated to another position and flanked by an adjacent methoxy group; and series of quinolin‐2(1H)‐one and quinoline derivatives of Irosustat were explored. The STS inhibitory activities of the synthesised compounds were assessed in a preparation of JEG‐3 cells. Stepwise enlargement of the aliphatic ring from 7 to 11 members increases potency, although a further increase in ring size is detrimental. The best STS inhibitors in vitro had IC₅₀ values between 0.015 and 0.025 nM . Other modifications made to Irosustat were found to either abolish or significantly weaken its activity. An azomethine adduct of Irosustat with N,N‐dimethylformamide (DMF) was isolated, and crystal structures of Irosustat and this adduct were determined. Docking studies were conducted to explore the potential interactions between compounds and the active site of STS, and suggest a sulfamoyl group transfer to formylglycine 75 during the inactivation mechanism.     

Synthesis and Field Tests of Possible Minor Components of the Sex Pheromone of Prionus californicus

Earlier work has shown that adult male Prionus californicus Motschulsky (Coleoptera: Cerambycidae) are attracted to the female-produced compound (3R,5S)-3,5-dimethyldodecanoic acid, and to a synthetic mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid. Here, we report the results of field trials that tested whether or not three structurally related compounds (methyl 3,5-dimethyldodecanoate, 3,5-dimethyltridecanoic acid, and 3,5-dimethylpentadecanoic acid), present in extracts of virgin females, are attractive, and whether or not they influence attraction to 3,5-dimethyldodecanoic acid. In a trial with single components, only traps baited with the acid or its methyl ester captured more beetles than did control traps; catches to the acid were five times higher than to the methyl ester. Another trial, excluding 3,5-dimethyldodecanoic acid, confirmed the activity of the methyl ester. Finally, addition of the three compounds to 3,5-dimethyldodecanoic acid, in the ratio found in extracts from female beetles, gave a catch similar to that of traps baited with 3,5-dimethyldodecanoic acid alone. Consequently, the function of these minor compounds remains undetermined.     

Aromatase and dual aromatase-steroid sulfatase inhibitors from the letrozole and vorozole templates

Concurrent inhibition of aromatase and steroid sulfatase (STS) may provide a more effective treatment for hormone‐dependent breast cancer than monotherapy against individual enzymes, and several dual aromatase–sulfatase inhibitors (DASIs) have been reported. Three aromatase inhibitors with sub‐nanomolar potency, better than the benchmark agent letrozole, were designed. To further explore the DASI concept, a new series of letrozole‐derived sulfamates and a vorozole‐based sulfamate were designed and biologically evaluated in JEG‐3 cells to reveal structure–activity relationships. Amongst achiral and racemic compounds, 2‐bromo‐4‐(2‐(4‐cyanophenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethyl)phenyl sulfamate is the most potent DASI (aromatase: IC₅₀=0.87 nM ; STS: IC₅₀=593 nM ). The enantiomers of the phenolic precursor to this compound were separated by chiral HPLC and their absolute configuration determined by X‐ray crystallography. Following conversion to their corresponding sulfamates, the S‐(+)‐enantiomer was found to inhibit aromatase and sulfatase most potently (aromatase: IC₅₀=0.52 nM ; STS: IC₅₀=280 nM ). The docking of each enantiomer and other ligands into the aromatase and sulfatase active sites was also investigated.     

Physical and Chemical Processes to Enhance Oil Recovery from Condensed Corn Distillers Solubles

Oil recovery from corn fermentation co-products can provide feedstock for biodiesel production. The effects of physical and chemical processes on oil recovery from condensed corn distillers solubles (CCDS) were investigated. Heating disrupted physical interactions in the CCDS and increased oil recovery by 2.5-fold when temperature was increased from 25 to 59 °C. Oil recovery at acidic pH conditions was significantly greater than at alkaline pH. Oil recovery at alkaline pH was increased by heating and addition of the reducing agent, sodium metabisulfite. Oil extraction using polar solvents isopropanol and butanol achieved greater than 80% oil recovery. When oil was co-extracted with zein using hexane and ethanol as co-solvents, the greatest total oil recovery was achieved, 89%. Churning CCDS at pH 3.5, 50 °C for 3 h achieved up to 80% oil recovery. This study provides data for designing further effective methods for oil separation from corn ethanol co-products.     

Combustion characteristics of candles made from hydrogenated soybean oil

Hydrogenated soybean oil, referred to as soywax by candle makers, is a renewable and biodegradable alternative to paraffin wax in candle manufacturing. Soywax was investigated for its tendency to produce soot as well as potentially harmful organic volatiles (acrolein, formaldehyde, and acetaldehyde) during combustion. Beeswax and paraffin candles were used as references. A considerable amount of soot was produced from the combustion of paraffin candles, but little or none was observed from soywax candles. Compared to paraffin candles, soywax candles burned at a significantly slower rate and required less air. Small amounts of formaldehyde were detected and quantified in the fumes of burning paraffin candles. However, formaldehyde, peaks found in the chromatograms of soy- and beeswax candles were similar to or slightly higher than that of the blank. Since soywax candles exhibited burning properties similar to those of beeswax candles, soywax shows promise in candle applications.     

Response to walnut olfactory and visual cues by the parasitic wasp Diachasmimorpha juglandis

Diachasmimorpha juglandis is a specialist parasitoid attacking fly larvae in the genus Rhagoletis that feed exclusively on walnut fruit husks. In a free-foraging assay comparing response to uninfested, infested, and mechanically damaged fruits, we first determined that D. juglandis use host feeding damage on the fruit as a cue for host presence. In another free-foraging assay that used artificial walnut models and wind tunnel experiments, D. juglandis distinguished infested from uninfested fruits by using either olfactory or visual cues separately. However, the response rate of wasps in the wind tunnel was raised considerably when visual cues were also available. We analyzed the volatile compounds emitted by cohorts of uninfested, mechanically damaged, and infested fruits 1, 3, 5, 8, and 10 days after oviposition by flies into the infested fruits. Total volatile emissions did not differ significantly among treatments, but quantitative changes in volatiles distinguished infested fruits from uninfested and damaged fruits. The fact that parasitoids did not distinguish between infested and damaged fruits in assays where damage was visible indicates that they rely on visual cues when those are available.