The structures of four bombesins and their cloned precursor-encoding cDNAs from acid-solvated skin secretion of the European yellow-bellied toad, Bombina variegata

Four different bombesins (bombesin, His(6)-bombesin, Phe(13)-bombesin and Asp(2)-, Phe(4)-SAP-bombesin) have been identified by a systematic sequencing study of peptides in reverse phase HPLC fractions of the skin secretion of the European yellow-bellied toad, Bombina variegata, that had been solvated in 0.1% (v/v) aqueous trifluoroacetic acid (TFA) and stored frozen at -20°C for 12 years. By using a 3'- and 5'-RACE PCR strategy, the corresponding biosynthetic precursor-encoding cDNAs of all four peptides were cloned from a cDNA library made from the same long-term frozen, acid-solvated skin secretion sample following thawing and lyophilization. Canonical bombesin and His(6)-bombesin are classical bombesin sub-family members, whereas Phe(13)-bombesin and Asp(2)-, Phe(4)-SAP-bombesin, belong to the litorin/ranatensin sub-family of bombesin-like peptides (BLPs). Assignment of these peptides to respective sub-families, was based upon both their primary structural similarities and their comparative pharmacological activities. An interesting observation in this study, was that the nucleotide sequences of the open-reading frames of cloned cDNAs encoding bombesin and its His(6)-substituted analog, were identical except for a single base that was responsible for the change observed at the position 6 residue in the mature peptide from Asn to His. In contrast, the precursor cDNA nucleotide sequences encoding the Phe(13)-bombesins, exhibited 53 base differences. The pharmacological activities of synthetic replicates of each bombesin were compared using two different mammalian smooth muscle preparations and all four peptides were found to be active. However, there were significant differences in their relative potencies.

Effect of precursor on the performance of alumina for the dehydration of methanol to dimethyl ether

Dimethyl ether (DME) is amongst one of the most promising alternative, renewable and clean fuels being considered as a future energy carrier. In this study, the comparative catalytic performance of γ-Al2O3 prepared from two common precursors (aluminum nitrate (AN) and aluminum chloride (AC)) is presented. The impact of calcination temperature was evaluated in order to optimize both the precursor and pre-treatment conditions for the production of DME from methanol in a fixed bed reactor. The catalysts were characterized by TGA, XRD, BET and TPD-pyridine. Under reaction conditions where the temperature ranged from 180 °C to 300 °C with a WHSV = 12.1 h−1 it was found that all the catalysts prepared from AN(η-Al2O3) showed higher activity, at all calcination temperatures, than those prepared from AC(γ-Al2O3). In this study the optimum catalyst was produced from AN and calcined at 550 °C. This catalyst showed a high degree of stability and had double the activity of the commercial γ-Al2O3 or 87% of the activity of commercial ZSM-5(80) at 250 °C.

Toluene dioxygenase-catalyzed cis-dihydroxylation of benzo[b]thiophenes and benzo[b]furans: synthesis of benzo[b]thiophene 2,3-oxide

Enzymatic cis-dihydroxylation of benzo[b]thiophene, benzo[b]furan and several methyl substituted derivatives was found to occur in both the carbocyclic and heterocyclic rings. Relative and absolute configurations and enantiopurities of the resulting dihydrodiols were determined. Hydrogenation of the alkene bond in carbocyclic cis-dihydrodiols and ring-opening epimerization/reduction reactions of heterocyclic cis/trans-dihydrodiols were also studied. The relatively stable heterocyclic dihydrodiols of benzo[b]thiophene and benzo[b]furan showed a strong preference for the trans configuration in aqueous solutions. The 2,3-dihydrodiol metabolite of benzo[b]thiophene was utilized as a precursor in the chemoenzymatic synthesis of the unstable arene oxide, benzo[b]thiophene 2,3-oxide.

Analytical approximations to numerical solutions of theoretical emission measure distributions

Emission line fluxes from cool stars are widely used to establish an apparent emission measure distribution, EmdApp(Te), between temperatures characteristic of the low transition region and the low corona. The true emission measure distribution, EmdTrue(Te), is determined by the energy balance and geometry adopted and, with a numerical model, can be used to predict EmdApp(Te), to guide further modelling. The scaling laws that exist between coronal parameters arise from the dimensions of the terms in the energy balance equation. Here, analytical approximations to numerical solutions for EmdTrue(Te) are presented, which show how the constants in the coronal scaling laws are determined. The apparent emission measure distributions show a minimum value at some T0 and a maximum at the mean coronal temperature Tc (although in some stars, emission from active regions can contribute). It is shown that, for the energy balance and geometry adopted, the analytical values of the emission measure and electron pressure at T0 and Tc depend on only three parameters: the stellar surface gravity and the values of T0 and Tc. The results are tested against full numerical solutions for e Eri (K2 V) and are applied to Procyon (a CMi, F5 IV/V). The analytical approximations can be used to restrict the required range of full numerical solutions, to check the assumed geometry and to show where the adopted energy balance may not be appropriate. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

DRIFTS/MS/Isotopic Labeling Study on the NO-Moderated Decomposition of a Silica-Supported Nickel Nitrate Catalyst Precursor

In the preparation of silica-supported nickel oxide from nickel nitrate impregnation and drying, the replacement of the traditional air calcination step by a thermal treatment in 1% NO/Ar prevents agglomeration, resulting in highly dispersed NiO. The mechanism by which NO prevents agglomeration was investigated by using combined in situ diffuse reflectance infrared fourier transform (DRIFT) spectroscopy and mass spectrometry (MS). After impregnation and drying, a supported nickel hydroxynitrate phase with composition Ni(3)(NO(3))(2)(OH)(4) had been formed. Comparison of the evolution of the decomposition gases during the thermal decomposition of Ni(3)(NO(3))(2)(OH)(4) in labeled and unlabeled NO and O(2) revealed that NO scavenges oxygen radicals, forming NO(2). The DRIFT spectra revealed that the surface speciation evolved differently in the presence of NO as compared with in O(2) or Ar. It is proposed that oxygen scavenging by NO depletes the Ni(3)(NO(3))(2)(OH)(4) phase of nitrate groups, creating nucleation sites for the formation of NiO, which leads to very small (similar to 4 nm) NiO particles and prevents agglomeration.

Molecular mapping the presence of druggable targets in preinvasive and precursor breast lesions:a comprehensive review of biomarkers related to therapeutic interventions

The analysis of clinical breast samples using biomarkers is integral to current breast cancer management. Currently, a limited number of targeted therapies are standard of care in breast cancer treatment. However, these targeted therapies are only suitable for a subset of patients and resistance may occur. Strategies to prevent the occurrence of invasive lesions are required to reduce the morbidity and mortality associated with the development of cancer. In theory, application of targeted therapies to pre-invasive lesions will prevent their progression to invasive lesions with full malignant potential. The diagnostic challenge for pathologists is to make interpretative decisions on early detected pre-invasive lesions. Overall, only a small proportion of these pre-invasive lesions will progress to invasive carcinoma and morphological assessment is an imprecise and subjective means to differentiate histologically identical lesions with varying malignant potential. Therefore differential biomarker analysis in pre-invasive lesions may prevent overtreatment with surgery and provide a predictive indicator of response to therapy. There follows a review of established and emerging potential druggable targets in pre-invasive lesions and correlation with lesion morphology.

STEADY-STATE SOLUTIONS IN NONLINEAR DIFFUSIVE SHOCK ACCELERATION

Stationary solutions to the equations of nonlinear diffusive shock acceleration play a fundamental role in the theory of cosmic-ray acceleration. Their existence usually requires that a fraction of the accelerated particles be allowed to escape from the system. Because the scattering mean free path is thought to be an increasing function of energy, this condition is conventionally implemented as an upper cutoff in energy space-particles are then permitted to escape from any part of the system, once their energy exceeds this limit. However, because accelerated particles are responsible for the substantial amplification of the ambient magnetic field in a region upstream of the shock front, we examine an alternative approach in which particles escape over a spatial boundary. We use a simple iterative scheme that constructs stationary numerical solutions to the coupled kinetic and hydrodynamic equations. For parameters appropriate for supernova remnants, we find stationary solutions with efficient acceleration when the escape boundary is placed at the point where growth and advection of strongly driven nonresonant waves are in balance. We also present the energy dependence of the distribution function close to the energy where it cuts off-a diagnostic that is in principle accessible to observation.

Fixed Bed Study of Ammonia Removal from Aqueous Solutions Using Natural Zeolite

Purpose
– The purpose of this paper is to investigate the performance of natural Jordanian zeolite tuff to remove ammonia from aqueous solutions using a laboratory batch method and fixed-bed column apparatus. Equilibrium data were fitted to Langmuir and Freundlich models.

Design/methodology/approach
– Column experiments were conducted in packed bed column. The used apparatus consisted of a bench-mounted glass column of 2.5 cm inside diameter and 100 cm height (column volume = 490 cm3). The column was packed with a certain amount of zeolite to give the desired bed height. The feeding solution was supplied from a 30 liter plastic container at the beginning of each experiment and fed to the column down-flow through a glass flow meter having a working range of 10-280ml/min.

Findings
– Ammonium ion exchange by natural Jordanian zeolite data were fitted by Langmuir and Freundlich isotherms. Continuous sorption of ammonium ions by natural Jordanian zeolite tuff has proven to be effective in decreasing concentrations ranging from 15-50 mg NH4-N/L down to levels below 1 mg/l. Breakthrough time increased by increasing the bed depth as well as decreasing zeolite particle size, solution flow-rate, initial NH4+ concentration and pH. Sorption of ammonium by the zeolite under the tested conditions gave the sorption capacity of 28 mg NH4-N/L at 20°C, and 32 mg NH4-N/L at 30°C.

Originality/value
– This research investigates the performance of natural Jordanian zeolite tuff to remove ammonia from aqueous solutions using a laboratory batch method and fixed-bed column apparatus. The equilibrium data of the sorption of Ammonia were plotted by using the Langmuir and Freundlich isotherms, then the experimental data were compared to the predictions of the above equilibrium isotherm models. It is clear that the NH4+ ion exchange data fitted better with Langmuir isotherm than with Freundlich model and gave an adequate correlation coefficient value.

Endodontic 'Solutions'. Part 2:An audit comparing current practice in Belfast with UK and Republic of Ireland Dental Schools

Endodontic lubricants, irrigating solutions and medicaments help reduce the microbial load within root canals. Primary and secondary cases involve different microbes. Each'solution'or combinations thereof could play a significant role but no detailed guidelines exist on their use. An audit was undertaken to compare current practice in Belfast Dental School to the others across the UK and Republic of Ireland (ROI). This audit highlighted three main differences between Belfast and other dental schools. Many other institutions utilized other irrigants besides sodium hypochlorite (NaOCl), different intracanal medicaments, including calcium hydroxide, and higher concentrations of NaOCl. Having gathered this information, we ask, 'Is there sufficient evidence to change the endodontic regime currently used at Belfast Dental School?'. Using the findings from the literature review (Part 1), we introduce new evidence-based protocols for primary and secondary cases for use in Belfast Dental School. Clinical Relevance: In the absence of detailed clinical guidelines on the use of endodontic lubricants, irrigants and medicaments in primary and secondary cases, it is important to be aware of current practice in UK and ROI dental schools where dentists and specialists are trained.

Endodontic 'solutions' part 1:A literature review on the use of endodontic lubricants, irrigants and medicaments

Endodontic lubricants, irrigants and medicaments help prepare and disinfect root canal systems (RCS) but primary and secondary cases involve different microbes and therefore it is unlikely that one protocol will be effective for both case types. Each individual 'solution' or sequence of 'solutions' could play a significant role in each case type, but there are no detailed published guidelines in existence. To help inform clinical practice it was decided to undertake a literature review followed by a UK and Republic of Ireland wide audit on current endodontic 'solution' usage within dental schools. The literature review was undertaken under the following headings: pre-op oral rinse; file lubricants; root canal irrigants and intracanal medicaments and provides an evidence base for protocol development for both primary and retreatment cases. The audit project and the protocols developed from the findings of both the literature review and audit will be presented in Part 2.