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Additive manufacturing via direct ink writing and microwave dielectric characterisation of commercially produced low sintering temperature bismuth molybdenum oxide ceramics, have been both performed for the first time, following a powder-to-product holistic approach. We demonstrated that direct ink writing is an excellent candidate for producing dielectric substrates to be used for wireless telecommunication applications operating at microwave (MW) frequencies, with great repeatability and properties comparable to ceramics fabricated via conventional processing routes. The optimum density (relative density of ρr ≈ 93%) of the 3D printed test samples was obtained by sintering at 660 °C for 2 h, resulting in a relative permittivity er = 35.7, dielectric loss tanδ = 0.0004 and microwave quality factor Q × f = 14,928 GHz. Sintering at higher temperatures promoted a porosity increase due to mismatching grain growth mechanisms and phase decomposition, that collectively hindered the test samples’ microwave dielectric performance in terms of achievable relative permittivity (er) and dielectric loss (tanδ).

Low-dose palliative radiation may offer symptomatic relief in patients with spinal metastases from primary renal cell cancer and is unlikely to result in radiation injury. Patients with advanced malignancy requiring palliative radiation are often also receiving chemotherapy. Synergistic adverse effects resulting from combined palliative radiation and novel antiprogrammed cell death-1 (anti-PD 1) and/or multityrosine kinase inhibitors are rare. We report about a 60-year-old woman with metastatic clear-cell renal cancer, status post-left nephrectomy, with debilitating mid-back pain from metastatic tumor burden and foraminal nerve compression. Her chemotherapeutic regimen was repeatedly altered because of progression of disease until she was maintained on the anti-PD 1 checkpoint inhibitor, nivolumab. She received palliative radiation to her thoracic spine over a 2-week period, and nivolumab was then switched to cabozantinib midway through a course of palliative radiation. The patient rapidly developed severe esophagitis, progressing to esophageal stricture, and required placement of a percutaneous endoscopic gastrostomy tube. She was successfully treated with serial esophageal dilation and hyperbaric oxygen treatments to diminish inflammation and improve tissue vascularity. Concurrent use of anti-PD 1 and/or multityrosine kinase drugs may accelerate development of radiation injury regardless of radiation dosage. Radiation-induced esophageal stricture was managed successfully in this patient with serial esophageal dilation and adjuvant hyperbaric oxygen.

Background MRI of hyperpolarized 129 Xenon (HP 129 Xe) is increasingly utilized for investigating pulmonary function. The solubility of HP 129 Xe in lung tissue, blood plasma (Barrier), and red blood cells (RBC), with unique chemical shifts, enables spectroscopic imaging of potential imaging biomarkers of gas exchange and microstructural pulmonary physiology. Purpose To quantify global average and regional repeatability of Barrier:gas, RBC:gas, and RBC:Barrier ratios derived from dissolved-phase 129 Xe imaging and their dependence on intervisit changes in lung inflation volume. Study type Prospective. Population Fourteen healthy volunteers. One subject was unable to complete the study resulting in 13 subjects for analysis (eight female, five male, ages 24-69, 53.8 ± 13.9). Field strength 1.5T. Assessment Subjects were imaged using a 3D radial 1-point Dixon method to separate Barrier and RBC component signals, at two different timepoints, with ~1 month between visits. RBC:Gas, Barrier:Gas, and RBC:Barrier measures were compared across time and with pulmonary function tests (PFTs). Statistical tests Repeatablilty was quantified using Bland-Altman plots, coefficient of repeatability, coefficient of variation (CV), and intraclass correlation coefficients (ICCs). Dependence of imaging measures on PFTs and lung volume was evaluated using Spearman and Pearson correlation coefficients, respectively. Statistical significance was determined by F-test for intraclass correlations, and t-test for Spearman correlations and regression. Results Mean RBC:Gas, Barrier:Gas, and RBC:Barrier had CVs of 19.2%, 20.0%, and 11.5%, respectively, and had significant ICCs, equal to 0.78, 0.79, and 0.92, respectively. Intervisit differences in RBC:Barrier were significantly correlated with intervisit differences in DLCO (r = 0.93, P = 0.007). Significant correlations with intervisit lung volume differences and intervisit differences in mean RBC:Gas (r = -0.73, P = 0.005) and Barrier:Gas (r = -0.69, P = 0.009) were found. Data conclusion Three commonly used 129 Xe MRI-based measures of gas-exchange show good repeatability, particularly the Barrier:RBC ratio, which did not depend on lung inflation volume and was strongly associated with intervisit changes in DLCO . Level of evidence 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1182-1190.

The planktonic synthesis of reduced organophosphorus molecules, such as alkylphosphonates and aminophosphonates, represents one half of a vast global oceanic phosphorus redox cycle. Whilst alkylphosphonates tend to accumulate in recalcitrant dissolved organic matter, aminophosphonates do not. Here, we identify three bacterial 2-aminoethylphosphonate (2AEP) transporters, named AepXVW, AepP and AepSTU, whose synthesis is independent of phosphate concentrations (phosphate-insensitive). AepXVW is found in diverse marine heterotrophs and is ubiquitously distributed in mesopelagic and epipelagic waters. Unlike the archetypal phosphonate binding protein, PhnD, AepX has high affinity and high specificity for 2AEP (Stappia stellulata AepX Kd 23 ± 4 nM; methylphosphonate Kd 3.4 ± 0.3 mM). In the global ocean, aepX is heavily transcribed (~100-fold>phnD) independently of phosphate and nitrogen concentrations. Collectively, our data identifies a mechanism responsible for a major oxidation process in the marine phosphorus redox cycle and suggests 2AEP may be an important source of regenerated phosphate and ammonium, which are required for oceanic primary production., Here the authors show that 2-aminoethylphosphonate (2AEP) mineralisation is widespread in the global ocean, operating independently of exogenous inorganic phosphate concentration. They propose 2AEP may be a major route for the regeneration of phosphate required to support marine primary production.

PURPOSE: The MR properties (chemical shifts and R(2)* decay rates) of dissolved-phase hyperpolarized (HP) (129)Xe are confounded by the large magnetic field inhomogeneity present in the lung. This work improves measurements of these properties using a model-based image reconstruction to characterize the R(2)* decay rates of dissolved-phase HP (129)Xe in healthy subjects and patients with idiopathic pulmonary fibrosis (IPF). METHODS: Whole lung MRS and 3D radial MRI with four gradient echoes were performed after inhalation of HP (129)Xe in healthy subjects and patients with IPF. A model-based image reconstruction formulated as a regularized optimization problem was solved iteratively to measure regional signal intensity in the gas, barrier, and red blood cell (RBC) compartments, while simultaneously measuring their chemical shifts and R(2)* decay rates. RESULTS: The estimation of spectral properties reduced artifacts in images of HP (129)Xe in the gas, barrier, and RBC compartments and improved image SNR by over 20%. R(2)* decay rates of the RBC and barrier compartments were lower in patients with IPF compared to healthy subjects (P < 0.001 and P=0.005, respectively) and correlated to DL(CO) (R=0.71 and 0.64, respectively). Chemical shift of the RBC component measured with whole lung spectroscopy was significantly different between IPF and normal subjects (P = 0.022). CONCLUSION: Estimates for R(2)* in both barrier and RBC dissolved-phase HP (129)Xe compartments using a regional signal model improved image quality for dissolved phase images and provided additional biomarkers of lung injury in IPF.

The goal of our study was to determine the susceptibility of different pancreatic cell lines to clinically applicable photodynamic therapy (PDT). The efficacy of PDT of two different commercially available photosensitizers, verteporfin and sodium porfimer, was compared using a panel of four different pancreatic cancer cell lines, PANC-1, BxPC-3, CAPAN-2, and MIA PaCa-2, and an immortalized non-neoplastic pancreatic ductal epithelium cell line, HPNE. The minimum effective concentrations and dose-dependent curves of verteporfin and sodium porfimer on PANC-1 were determined. Since pancreatic cancer is known to have significant stromal components, the effect of PDT on stromal cells was also assessed. To mimic tumor–stroma interaction, a co-culture of primary human fibroblasts or human pancreatic stellate cell (HPSCs) line with PANC-1 was used to test verteporfin-PDT-mediated cell death of PANC-1. Two cytokines (TNF-α and IL-1β) were used for stimulation of primary fibroblasts (derived from human esophageal biopsies) or HPSCs. The increased expression of smooth muscle actin (α-SMA) confirmed the activation of fibroblasts or HPSC upon treatment with TNF-α and IL-1β. Cell death assays showed that both sodium porfimer- and verteporfin-mediated PDT-induced cell death in a dose-dependent manner. However, verteporfin-PDT treatment had a greater efficiency with 60× lower concentration than sodium porfimer-PDT in the PANC-1 incubated with stimulated fibroblasts or HPSC. Moreover, activation of stromal cells did not affect the treatment of the pancreatic cancer cell lines, suggesting that the effects of PDT are independent of the inflammatory microenvironment found in this two-dimensional culture model of cancers.

Low sintering temperature, ultra-low loss microwave ceramics are envisaged as future dielectrics for fabricating low temperature co-fired ceramic (LTCC) components for 5G applications. Low sintering temperature bismuth molybdate β-Bi2Mo2O9 ceramic powders have been synthesised using a solid-state reaction method. Their additive manufacture and resulting microwave properties are reported for the first time. Optimum densification occurred for 3D printed samples sintered 4 hours at 670°C which resulted in a maximum relative density (ρr) of 92%, relative permittivity (er) of 34, dielectric loss (tanδ) of 0.0007, giving a microwave quality factor (Qxf) of 10,050 GHz, properties attractive for LTCC applications.

A series of lanthanide metal–organic frameworks (MOFs) of the general formula [Ln(Hodip)(H2O)]·nH2O (Sm, 1; Eu, 2; Gd, 3; Tb, 4; Dy, 5; Er, 6; H4odip = 5,5′-oxydiisophthalic acid) have been prepared and shown crystallographically to have isostructural three-dimensional frameworks. The fluorescence emission spectra of the europium compound 2, which is red, and the terbium compound 4, which is green, show characteristic peaks for transitions involving the metal centres, whereas that for the gadolinium compound 3 is dominated by transitions involving Hodip. Using a 1 : 1 : 1 mixture of europium, gadolinium and terbium nitrates in the synthesis resulted in the mixed-metal MOF [Gd0.17Tb0.19Eu0.64(Hodip)(H2O)]·nH2O 7, for which the ratio of the metal ions was determined using EDX spectroscopy. The fluorescence emission spectrum of 7 is dominated by europium emission bands reflecting the higher proportion of Eu3+ centres and quenching of the terbium fluorescence by metal-to-metal energy transfer. A series of core–shell MOF materials based on the Ln(Hodip)(H2O) framework have been prepared in order to isolate the lanthanides in different domains within the crystals. The emission spectra for materials with Gd@Tb@Eu (8) and Tb@Eu@Gd (9) are dominated by terbium emissions, suggesting that physical separation from europium suppresses quenching. In contrast, the material with Eu@Gd@Tb (10) shows only broad ligand bands and europium emissions. This confirms that core–shell MOFs have different fluorescence properties to simple mixed-metal MOFs, demonstrating that the spatial distribution of the metals within a mixed-lanthanide MOF affects the fluorescence behaviour.

We report here on a method to functionalize silicone surfaces, which is based on the deposition of silicone-containing amphiphilic block copolymers from a colloidal water–ethanol dispersion. Using cross-linked silicones (Sylgard 184) as substrates, copolymers composed of two poly(glycerol monomethacrylate) (PGMMA) terminal blocks and a central poly(dimethylsiloxane) (PDMS) block can be effectively deposited when the PDMS content is ≥46 wt%. (≥65 mol%); the deposition provides smooth and stable surfaces, which significantly affected the protein adsorption behaviour of the substrate, suggesting a possible application in biomaterial coating. In air, the block copolymer surface films underwent a reorganization, which differs from the classical hydrophobic recovery of silicones and may be related to a disordered folding of lamellar structures. This led to a predominant surface coverage by thin, possibly monomolecular layers, which displayed a non-restructuring polar surface. However, as a consequence of the reorganization also larger aggregates were produced, albeit in relatively small numbers; these aggregates underwent a progressive hydrophobization (in this case a hydrophobic recovery) and probably dominated the contact angle behaviour of the material. In summary, the colloidal deposition of amphiphilic silicone-based block copolymers successfully modifies the surface properties of silicone substrates; however, attention must paid to reorganization phenomena in order to maximize the stability of the coating.

We report for the first time the combination of ATRP and ring-opening episulfide polymerization as a means to synthesize polysulfide-based low-dispersity amphiphilic block copolymers. The most significant finding is the possibility to perform ATRP under mild conditions using poly(propylene sulfide) macroinitiators, apparently without any significant copper sequestration by the polysulfides. Using glycerol monomethacrylate (GMMA) as a hydrophilic monomer, the polymers self-assembled in colloidal structures with a morphology depending on the PS/GMMA ratio, but also probably on GMMA degree of polymerization. We here also present a new AFM-based method to calculate the average number of amphiphilic macromolecules per micelle. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A family of ferrocene-functionalised receptors of different topologies have been used as receptors for anions. The compounds have been designed to contain both amine nitrogen and ether oxygen atoms and comprises from monoaza to pentaaza derivatives both open-chain (L1, L2, L3) or cyclic (L4, L5) and having from one to five ferrocenyl groups. Solution studies directed to determine the protonation constants of L1, L2 and L3 have been carried out in water (0.1 mol dm3 KNO3, 25 °C) and those of L4 and L5 in 1,4-dioxane-water (70:30 v/v, 0.1 mol dm -3 KNO 3, 25 °C). The protonation behaviour of the receptors can be explained taking into account electrostatic considerations. Speciation studies in the presence of phosphate have been carried out in water for L', L2 and L3 and in dioxane-water for L4 and L5. Speciation studies have also been performed in the presence of ATP with L1, L2 and L3 in water. Selectivity of a mixture of receptors against a certain anion is discussed in terms of ternary diagrams. The shift of the redox potential of the ferrocenyl groups as a function of the pH has been studied. The difference between the oxidation potentials at basic and acidic pH has been determined experimentally and is compared with that theoretically predicted using an electrostatic model previously reported. The electrochemical shift in the presence of ATP and phosphate has been measured in water for L1, L2 and L3 and in the presence of phosphate and sulfate in 1,4-dioxane-water for L4 and L5 as a function of the pH. The electrochemical response found against those anions is quite poor with maximum cathodic shifts off. 30tO mV. The electrochemical response induced by HSO4 and H2PO4- has also been studied in acetonitrile solutions where a large cathodic shift for H 2PO 4- up to ca. 200 mV was found. © The Royal Society of Chemistry 2000.

Potentiometric and electrochemical studies have been carried out with a family of ferrocene redox-functionalised polyamines (L1–L5) and have been directed towards the discrimination, using electrochemical techniques, between the two oxoanions phosphate and sulfate and the electrochemical sensing of ATP. Potentiometric titrations were carried out in THF–water (70∶30 v/v, 0.1 mol dm–3 tetrabutylammonium perchlorate, 25 °C) for L1, L2, L3, L5 and in water (0.1 mol dm–3 potassium nitrate, 25 °C) for L4. Potentiometric data indicate that all receptors studied form stable complexes with sulfate, phosphate and ATP. Distribution for the ternary diagram system sulfate–phosphate–L2 shows pH dependent selectivity patterns; [L2HjSO4]j – 2 species exist at greater than 90% in the pH range 3–4, whereas the corresponding phosphate complexes are the main species in the neutral and basic pH range. The electrochemical studies are in agreement with the speciation results. Sulfate produces in all cyclic receptors maximum cathodic shifts of the redox potential of the ferrocenyl groups around pH 3–4, whereas maximum cathodic shifts for phosphate were found between pH 7 and 8. This behaviour is not observed for the open-chain tetraamine L5. Selective quantitative electrochemical recognition of sulfate and phosphate in the presence of competing anions in aqueous solution has been achieved using the redox-active polyaza ferrocene macrocyclic L2, L3 and L4 receptors. Additionally ATP is able to cathodically shift the oxidation potential of the ferrocenyl groups of L2 and L3 receptors by up to 100 mV. The electrochemical response of L3 against ADP and AMP is also reported.

The cellular distribution of TAR DNA binding protein (TDP-43) is disrupted in several neurodegenerative disorders, including frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U subtype) and amyotrophic lateral sclerosis (ALS). In these conditions, TDP-43 is found in neuronal cytoplasmic inclusions, with loss of the normal nuclear expression. The mechanisms leading to TDP-43 redistribution and its role in disease pathophysiology remain unknown. We describe an in vitro neural tissue model that reproduces TDP-43 relocalization and inclusion formation. Two week-old coronal organotypic mouse brain slice cultures were treated with tunicamycin for 7 days. In cortical regions of treated slice cultures, cytoplasmic inclusions of TDP-43 immunoreactivity were observed, with loss of nuclear TDP-43 immunoreactivity. These inclusions were found in both astrocytes and neurons, and were of both skein-like and round morphologies. In contrast, TDP-43 cytoplasmic inclusions were not found in slices treated with staurosporine to induce apoptosis, or with trans-4-carboxy-l-proline (PDC) to induce chronic glutamate excitotoxicity. Furthermore, TDP-43 cytoplasmic inclusions did not co-localize with cleaved caspase-3, suggesting that TDP-43 mislocalization does not generally accompany caspase activation or apoptosis. The induction of TDP-43 cytoplasmic translocation in cerebrocortical slice cultures by tunicamycin provides a platform for further mechanistic investigations of pathological processing of TDP-43.

A stable, monoprotic nitroxide spin probe is utilized as a model to study molecular collisions in aqueous electrolyte solutions. The rate constants of bimolecular collisions, K(col) for 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-carboxylic acid (CP) when it is uncharged (at low pH) and K(col)⁻ when it is charged (CP⁻; at high pH), are measured as functions of temperature and ionic strength. The ratio f* ≡ K(col)⁻/K(col) is a direct measure of the effect of charge on the collision rate. Neglecting the small differences in size and diffusion coefficients of CP and CP⁻, f* is the fractional change in collision rate due to Coulomb repulsion which was treated theoretically in Debye's classic paper [Trans. Electr. Chem. Soc. 1942, 82, 265]. K(col) and K(col)⁻ are determined from EPR spectral changes due to spin-spin interactions which are dominated by Heisenberg spin exchange under the conditions of these experiments. Values of f* vary linearly with values of κ · d in the range 0.4 < κ · d < 1.8, where κ and d are the inverse Debye screening length and the distance at closest approach, respectively. Values of d obtained in two independent ways, (1) from rotational correlation times measured by EPR and (2) by insisting that the experimental results be consistent with the Debye theory at infinite dilution, yield similar results. As the ionic strength is increased (κ increased), the screening effect reduces the effect of the Coulomb barrier more slowly than predicted by the Debye theory. While values of K(col) and K(col)⁻ vary substantially with T, approximately following the Stokes-Einstein-Smoluchowski equation, values of f* depend only slightly on temperature at a given value of κ · d, as is predicted by Debye's theory.

Five 8-(4-R-phenyl)-1-naphthol derivatives were prepared by PdCl2-catalysed electrophilic aromatic substitution. The pKa' values for these 1,8-disubstituted arene naphthols have been measured in acetonitrile/water (R = NO2, 8.42; R = Cl, 8.52; R = H, 8.56; R = Me 8.68; and R = OMe, 8.71) and indicate a correlation with the electronic nature of the arene substituent, as determined through LFER analysis. Contributions to the relative pKa' values have been interpreted, using M06-2X DFT calculations, as consisting of two components: A small contribution from initial OH–π bonding in the starting materials and a larger contribution from anion–π interactions in the products. Such effects have implications for a range of other systems.

Background: To compare the efficacy and tolerance of three prostaglandin analogues, bimatoprost, latanoprost and travoprost in patients with previously untreated open-angle glaucoma and ocular hypertension. Methods: Prospective randomized single (investigator) masked comparative clinical trial at the Taunton and Somerset NHS Hospital, Taunton, UK. Newly diagnosed, treatment naive glaucoma/ocular hypertension patients were recruited. Patients were randomized into three groups to receive one of the three prostaglandin analogues. Intraocular pressure (IOP) was measured before starting treatment and after 2 and 6 months of treatment. The IOP reduction and the tolerance profile of each drug were compared. The data were analysed on the basis of intention to treat, using analysis of covariance comparing IOP in the three groups at 2 and 6 months, adjusting for baseline IOP. Tolerance levels were compared using Kruskal–Wallis test. Results: Of the 122 patients, 40 patients were given bimatoprost, 42 received latanoprost and 40 had travoprost. At 2 months, there was a significant difference between the three treatment groups (P = 0.013) with bimatoprost achieving a greater reduction in IOP than the other two drops. However, at 6 months, the difference was not statistically significant (P = 0.13). There was no significant difference in the tolerance profile. Conclusion: All the three topical prostaglandin analogues are effective at lowering IOP, but bimatoprost was found to be most effective in the initial phase of the trial, and there was no statistically significant difference in the efficacy, among the three prostaglandin analogue eye drops after 6 months of treatment.

Summary Nucleoprotein complexes present challenges to genome stability by acting as potent blocks to replication. One attractive model of how such conflicts are resolved is direct targeting of blocked forks by helicases with the ability to displace the blocking protein-DNA complex. We show that Rep and UvrD each promote movement of E. coli replisomes blocked by nucleoprotein complexes in vitro, that such an activity is required to clear protein blocks (primarily transcription complexes) in vivo, and that a polarity of translocation opposite that of the replicative helicase is critical for this activity. However, these two helicases are not equivalent. Rep but not UvrD interacts physically and functionally with the replicative helicase. In contrast, UvrD likely provides a general means of protein-DNA complex turnover during replication, repair, and recombination. Rep and UvrD therefore provide two contrasting solutions as to how organisms may promote replication of protein-bound DNA.

Helicases play critical roles in all aspects of nucleic acid metabolism by catalyzing the remodeling of DNA and RNA structures. UvrD is an abundant helicase in Escherichia coli with well characterized functions in mismatch and nucleotide excision repair and a possible role in displacement of proteins such as RecA from single-stranded DNA. The mismatch repair protein MutL is known to stimulate UvrD. Here we show that the nucleotide excision repair proteins UvrA and UvrB can together stimulate UvrD-catalyzed unwinding of a range of DNA substrates containing strand discontinuities, including forked DNA substrates. The stimulation is specific for UvrD, as UvrAB failed to stimulate Rep helicase, a UvrD homologue. Moreover, although UvrAB can promote limited strand displacement, stimulation of UvrD did not require the strand displacement function of UvrAB. We conclude that UvrAB, like MutL, modulate UvrD helicase activity. This stimulation likely plays a role in DNA strand and protein displacement by UvrD in nucleotide excision repair. Promotion of UvrD-catalyzed unwinding of nicked duplexes by UvrAB may also explain the need for UvrAB and UvrD in Okazaki fragment processing in cells lacking DNA polymerase I. More generally, these data support the idea that helicase activity is regulated in vivo, with helicases acting as part of multisubunit complexes rather than in isolation.

The effects of ambient solar UV radiation (280 to 400 nm) were determined using 3 nat- ural marine protist communities incubated in 650 l tanks (minicosms) for 13 to 14 d over the summer of 2002-2003 at Davis Station, Antarctica. Minicosms were exposed to ambient light that was vari- ously attenuated to give treatments of photosynthetically active radiation (PAR, ≥385 nm wave- length), PAR + UV-A radiation (315 to 385 nm), and PAR + UV-A + 4 different treatments of UV-B radiation (280 to 315 nm) that simulated a range of equivalent depths (ED) in the water column from 4.43 to 7.15 m. Results showed a seasonal progression in the response of microbial communities to UV radiation exposure. The first experiment in November showed that the microbial community was sig- nificantly inhibited in the PAR + UV-A-exposed treatment but this inhibition declined with increas- ing addition of UV-B radiation. The second experiment in December showed that UV-A or UV-B radi- ation had few significant effects. Like in Expt 1, some taxa were inhibited by PAR + UV-A or promoted by UV-B, but most were inhibited at the highest UV-B irradiances (≤4.43 m ED). The last experiment in January showed UV-B induced inhibition of all but one of the dominant taxa. The sea- sonal transition in UV wavelengths responsible for inhibition of protists may be due to ozone reduc- tion, the light history of protists, and/or changes in species composition. The increasing UV-B- induced inhibition we observed over the summer corresponded to a decline in ozone concentrations over Davis. This recurrent decline in ozone over Antarctica between January and April coincides with blooms of diatoms that appear to have low UV-B tolerance but are responsible for ~47% of annual primary production in Antarctic waters.

The depth of seed dormancy can be influenced by a number of different environmental signals, but whether a common mechanism underlies this apparently similar response has yet to be investigated. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana Cape Verde Island accession seeds exposed to dry after-ripening (AR), or low temperature, nitrate and light when imbibed. Germination studies showed that the sensitivity of imbibed seeds to low temperature, nitrate and light was dependant upon the length of time spent AR following harvest. Seeds had an absolute requirement for light to complete dormancy release in all conditions, but this effect required an exposure to a prior dormancy relieving environment. Principal component analyses of the expression patterns observed grouped physiological states in a way that related to the depth of seed dormancy, rather than the type of environmental exposure. Furthermore, opposite changes in transcript abundance of genes in sets associated with dormancy, or dormancy relief through AR, were also related to the depth of dormancy and common to different environments. Besides these common quantitative changes, environment-specific gene expression patterns during dormancy relief are also described. For example, higher transcript abundance for genes linked to the process of nitrate accumulation, and nitrate reduction was associated with dormancy relief. The quantity of GA3ox1 transcripts increased during dormancy relief in all conditions, in particular when dormancy relief was completed by exposure to light. This contrasts with transcripts linked to abscisic acid (ABA) synthesis, which declined. The results are consistent with a role for the ABA/gibberellic acid balance in integrating dormancy-relieving environmental signals.

A new approach is reported for tailoring the pore geometry in five series of multivariate metal-organic frameworks (MOFs) based on the structure [Zn-2(bdc)(2)(dabco)] (bdc = 1,4-benzenedicarboxylate, dabco = 1,8-diazabicyclooctane), DMOF-1. A doping procedure has been adopted to form series of MOFs containing varying linker ratios. The series under investigation are [Zn-2(bdc)(2-x)(bdc-Br)(x)(dabco)]center dot nDMF 1 (bdc-Br = 2-bromo-1,4-benzenedicarboxylate), [Zn-2(bdc)(2-x)(bdc-I)(x)(dabco)]center dot nDMF 2 (bdc-I = 2-iodo-1,4-benzenedicarboxylate), [Zn-2(bdc)(2-x)(bdc-NO2)(x)(dabco)]center dot nDMF 3 (bdc-NO2 = 2-nitro-1,4-benzenedicarboxylate), [Zn-2(bdc)(2-x)(bdc-NH2)(x)(dabco)]center dot nDMF 4 (bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) and [Zn-2(bdc-Br)(2-x)(bdc-I)(x)(dabco)] nDMF 5. Series 1-3 demonstrate a functionality-dependent pore geometry transition from the square, open pores of DMOF-1 to rhomboidal, narrow pores with increasing proportion of the 2-substituted bdc linker, with the rhomboidal-pore MOFs also showing a temperature-dependent phase change. In contrast, all members of series 4 and 5 have uniform pore geometries. In series 4 this is a square pore topology, whilst series 5 exhibits the rhomboidal pore form. Computational analyses reveal that the pore size and shape in systems 1 and 2 is altered through non-covalent interactions between the organic linkers within the framework, and that this can be controlled by the ligand functionality and ratio. This approach affords the potential to tailor pore geometry and shape within MOFs through judicious choice of ligand ratios.

Many studies have demonstrated the need for processing of blocked replication forks to underpin genome duplication. UvrD helicase in Escherichia coli has been implicated in the processing of damaged replication forks, or the recombination intermediates formed from damaged forks. Here we show that UvrD can unwind forked DNA structures, in part due to the ability of UvrD to initiate unwinding from discontinuities within the phosphodiester backbone of DNA. UvrD does therefore have the capacity to target DNA intermediates of replication and recombination. Such an activity resulted in unwinding of what would be the parental duplex DNA ahead of either a stalled replication fork or a D-loop formed by recombination. However, UvrD had a substrate preference for fork structures having a nascent lagging strand at the branch point but no leading strand. Furthermore, at such structures the polarity of UvrD altered so that unwinding of the lagging strand predominated. This reaction is reminiscent of the PriC-Rep pathway of replication restart, suggesting that UvrD and Rep may have at least partially redundant functions.

Physiologically dormant seeds, like those of Arabidopsis, will cycle through dormant states as seasons change until the environment is favourable for seedling establishment. This phenomenon is widespread in the plant kingdom, but has not been studied at the molecular level. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana (accession Cvi) seeds in a range of dormant and dry after-ripened states during cycling. Principal component analysis of the expression patterns observed showed that they differed in newly imbibed primary dormant seeds, as commonly used in experimental studies, compared with those in the maintained primary and secondary dormant states that exist during cycling. Dormant and after-ripened seeds appear to have equally active although distinct gene expression programmes, dormant seeds having greatly reduced gene expression associated with protein synthesis, potentially controlling the completion of germination. A core set of 442 genes were identified that had higher expression in all dormant states compared with after-ripened states. Abscisic acid (ABA) responsive elements were significantly over-represented in this set of genes the expression of which was enhanced when multiple copies of the elements were present. ABA regulation of dormancy was further supported by expression patterns of key genes in ABA synthesis/catabolism, and dormancy loss in the presence of fluridone. The data support an ABA-gibberelic acid hormone balance mechanism controlling cycling through dormant states that depends on synthetic and catabolic pathways of both hormones. Many of the most highly expressed genes in dormant states were stress-related even in the absence of abiotic stress, indicating that ABA, stress and dormancy responses overlap significantly at the transcriptome level.

The frequency with which replication forks break down in all organisms requires that specific mechanisms ensure completion of genome duplication. In Escherichia coli a major pathway for reloading of the replicative apparatus at sites of fork breakdown is dependent on PriA helicase. PriA acts in conjunction with PriB and DnaT to effect loading of the replicative helicase DnaB back onto the lagging strand template, either at stalled fork structures or at recombination intermediates. Here we showed that PriB stimulates PriA helicase, acting to increase the apparent processivity of PriA. This stimulation correlates with the ability of PriB to form a ternary complex with PriA and DNA structures containing single-stranded DNA, suggesting that the known single-stranded DNA binding function of PriB facilitates unwinding by PriA helicase. This enhanced apparent processivity of PriA might play an important role in generating single-stranded DNA at stalled replication forks upon which to load DnaB. However, stimulation of PriA by PriB is not DNA structure-specific, demonstrating that targeting of stalled forks and recombination intermediates during replication restart likely resides with PriA alone.

PriA helicase is the major DNA replication restart initiator in Escherichia coli and acts to reload the replicative helicase DnaB back onto the chromosome at repaired replication forks and D-loops formed by recombination. We have discovered that PriA-catalysed unwinding of branched DNA substrates is stimulated specifically by contact with the single-strand DNA binding protein of E.coli, SSB. This stimulation requires binding of SSB to the initial DNA substrate and is effected via a physical interaction between PriA and the C-terminus of SSB. Stimulation of PriA by the SSB C-terminus may act to ensure that efficient PriA-catalysed reloading of DnaB occurs only onto the lagging strand template of repaired forks and D-loops. Correlation between the DNA repair and recombination defects of strains harbouring an SSB C-terminal mutation with inhibition of this SSB–PriA interaction in vitro suggests that SSB plays a critical role in facilitating PriA-directed replication restart. Taken together with previous data, these findings indicate that protein–protein interactions involving SSB may coordinate replication fork reloading from start to finish.

We describe the case of a 56-year old woman with no prior psychiatric history who was diagnosed with hormone receptor positive early-stage breast cancer and who developed severe mood changes after administration of anastrozole, which resolved after discontinuation of treatment. Aromatase inhibitors (AIs) are the preferred hormonal approach for postmenopausal women with estrogen hormone sensitive breast cancer. The third-generation agents (anastrozole, letrozole, and exemestane) have been shown to be more effective and safer than the selective estrogen receptor modulators tamoxifen and raloxifen. Treatment strategies with these agents include the use of an AI as an upfront strategy for 5 years, as a sequential approach after 2–3 years of tamoxifen, or as extended use after the classical 5 years of tamoxifen. The side effects of AIs, as compared with selective estrogen receptor modulators, are different, reflecting the specific mechanism of action of these drugs. AIs are well tolerated and cause a lower incidence of gynecological symptoms (vaginal bleeding, discharge, and endometrial neoplasia), venous thromboembolic events, and hot flashes compared with tamoxifen. However, the use of AIs have been associated with loss of bone density, arthralgia, myalgia, a negative effect on lipid metabolism, and cardiovascular risk (Tomao et al., 2011). Mood disturbances, somnolence, anxiety, fatigue, hot flashes, and memory impairment have been reported among patients receiving anastrozole as adjuvant therapy.

Recent evidence suggests that the level of interleukin-6 (IL-6) is elevated in Alzheimer's disease (AD) brains. IL-6 is produced by reactive glial cells and could potentially affect neuronal survival. Understanding the biochemical mechanism that regulates the production and release of IL-6 by astrocytic cells may help to identify potential targets for therapeutic intervention in AD. In the present study, glial fibrillary acidic protein-positive human U373MG astrocytoma cells were used as a model of reactive astrocytes. Production of IL-6 in response to drug treatment was monitored with an ELISA assay. Histamine (1-100 microM), substance P (SP; 1-100 nM), and human interleukin-1 beta (IL-1 beta; 1-30 pM) stimulated the release of IL-6 in a time- and concentration-dependent manner, with EC50 values of 4.5 microM, 8 nM, and 4.5 pM, respectively. The respective effects of histamine, SP, and IL-1 beta were effectively blocked by the histamine H1, SP, and IL-1 receptor antagonists, supporting a receptor-mediated event for these agents. Both histamine and SP enhanced the formation of inositol phosphates and increase intracellular calcium levels, suggesting that the phosphatidylinositol bisphosphate/protein kinase C pathway may be involved in the IL-6 release process. Indeed, phorbol 12-myristate 13-acetate, a protein kinase C activator, also evoked IL-6 release from the U373MG cells. On the other hand, IL-1 beta, which produces a much more robust release of IL-6 than histamine or SP, has no effect on inositol phosphate formation or intracellular calcium levels.(ABSTRACT TRUNCATED AT 250 WORDS)

The initiation of ethylene combustion (at Φ = 1 and Φ = 1.5) was studied over a wide range of temperatures (∼ 800-1620 K) in shock waves. Ignition delay data showed the presence of two or three different chemically controlling regimes in the combustion. At low temperatures (∼ 900-1000 K) the time development of a combustion bubble was tracked via Schlieren techniques and was observed to grow slowly. Unburnt gas between the bubble and end wall that was compressed and heated by the latter exploded and gave rise to a strong combustion wave that traveled back through the partially burning gas. Emission measurements showed the presence of CH*, OH*, C 2 *, and a continuum emission attributed to CO 2 * flame bands. C 2 * was found to be only important in richer mixtures. CH* was formed only microseconds ahead of the other diatomics.

The underlying mechanism by which skeletal muscle adapts to exercise training or chronic energy deprivation is largely unknown. To examine this question, rats were fed for 9 wk either with or without beta-guanadinopropionic acid (beta-GPA; 1% enriched diet), a creatine analog that is known to induce muscle adaptations similar to those induced by exercise training. Muscle phosphocreatine, ATP, and ATP/AMP ratios were all markedly decreased and led to the activation of AMP-activated protein kinase (AMPK) in the beta-GPA-fed rats compared with control rats. Under these conditions, nuclear respiratory factor-1 (NRF-1) binding activity, measured using a cDNA probe containing a sequence encoding for the promoter of delta-aminolevulinate (ALA) synthase, was increased by about eightfold in the muscle of beta-GPA-fed rats compared with the control group. Concomitantly, muscle ALA synthase mRNA and cytochrome c content were also increased. Mitochondrial density in both extensor digitorum longus and epitrochlearis from beta-GPA-fed rats was also increased by more than twofold compared with the control group. In conclusion, chronic phosphocreatine depletion during beta-GPA supplementation led to the activation of muscle AMPK that was associated with increased NRF-1 binding activity, increased cytochrome c content, and increased muscle mitochondrial density. Our data suggest that AMPK may play an important role in muscle adaptations to chronic energy stress and that it promotes mitochondrial biogenesis and expression of respiratory proteins through activation of NRF-1.

The liquid spray combustion of toluene has been studied in shock waves at temperatures between 900 and 2000 K and pressures up to 20 bar in oxygen–argon mixtures. The ignition delays were found to be dependent on the pressure and or fuel/oxygen ratio and the presence of up to 10% of additive. Two types of combustion were found: Type I occurred at lower temperatures and gave a steady combustion where the pressure rose steadily. Type II was detected at higher temperatures and in the presence of certain additives and gave a very sharp ‘spiked’ pressure rise. This phenomenon may be due to the occurrence of small droplet explosions or microcombustions and is similar to that of ‘knock’ in engines. The effect of additives on the ignition delay time depended on both the additive used and the concentration. 1% DTBP (di-tert-butyl peroxide) in the toluene has little effect on the ignition delay but 10% DTBP reduced it a little. 5% IPN (isopropyl nitrate) and EHN (ethyl hexyl nitrate) both had a neglible effect on the ignition time in this temperature region. IPN was also found to affect the type of combustion, changing it from Type I to Type II.

To examine the relationship between mitochondrial energy coupling in skeletal muscle and change in uncoupling protein 3 (UCP3) expression during the transition from the fed to fasted state, we used a novel noninvasive31P/13C NMR spectroscopic approach to measure the degree of mitochondrial energy coupling in the hind limb muscles of awake rats before and after a 48-h fast. Compared with fed levels, UCP3 mRNA and protein levels in the gastrocnemius increased 1.7- (p

This review focuses on the electrochemical and optical sensing of anionic guest species in organic and aqueous media using transition metal signalling units such as cobaltocenium, ferrocene and ruthenium (II) bipyridyl incorporated into various acyclic, macrocyclic and calix[4]arene ligand frameworks. © 2000 Elsevier Science S.A. All rights reserved.

The results of a new experimental programme to measure auto-ignition delay times in mainly lean (ϕ = 0.5) propane–air mixtures at intermediate temperatures in the range 850 K upwards and pressures 5–40 bar are described. The delays are compared to predictions obtained by the integration of two detailed chemical kinetic reaction schemes. Experimentally, a decrease in activation energy was observed at around 1000 K. The work shows that extrapolation of ignition delays obtained at high temperatures T>1000 K can lead to significant overestimation of the actual delay times at lower temperatures. Despite the introduction of additional key reactions the kinetic schemes used could not fully reproduce the delay times observed experimentally at temperature below ca. 1000 K.

We describe the in vitro selection and characterisation of virus derived from B/Beijing/1/87 passaged in the presence of zanamivir. During zanamivir passage, the phenotype of virus isolates was either drug dependent or drug resistant in plaque reduction assays. The susceptibility of the neuraminidase of the drug-dependent isolates was unchanged from that of the wild-type enzyme. The drug-dependent isolates contained two mutations in the viral haemagglutinin: V90A, close to the proposed secondary sialic acid-binding site, and L240Q, close to the primary sialic acid-binding site. Virus isolates that were drug resistant contained the same mutations in the haemagglutinin but also contained the mutation E116G in the neuraminidase. For the drug-dependent viruses, zanamivir susceptibility could not be measured because plaque numbers increased with increasing drug concentration. The in vitro zanamivir susceptibility of drug-resistant viruses was lower than that of the wild-type virus by a factor of 275- to >2532-fold. Neuraminidase containing the E116G mutation has a 33-fold lower affinity for zanamivir than the wild-type enzyme. The finding that the same haemagglutinin mutations are found in both drug-dependent and drug-resistant viruses confirms that the same changes to the receptor binding function can contribute to both phenotypes. This observation demonstrates the interplay between the influenza virus haemagglutinin and neuraminidase in escape from zanamivir inhibition in vitro.

Small forests in agricultural landscapes are generally thought to be population sinks where the nesting success of Neotropical migrant songbirds is too low to sustain populations. In 1996 and 1997, we assessed the nesting success and productivity of Wood Thrushes ( Hylocichla mustelina) and Rose-breasted Grosbeaks ( Pheucticus ludovicianus) in the Region of Waterloo, a highly fragmented agricultural landscape with 14% forest cover in southwestern Ontario. We located 154 Wood Thrush nests and 63 Rose-breasted Grosbeak nests in 26 small forest fragments (3–14 ha) and 15 large fragments (26–140 ha). We used the Mayfield method to determine nesting success. Across all sites nesting success was 51% for Wood Thrushes and 46% for Rose-breasted Grosbeaks. Nesting success and productivity rates were used in a simple population growth model that suggested that the Wood Thrushes but not the Rose-breasted Grosbeaks were a self-sustaining population. Forest size and distance of nests to the nearest forest edge (measured in five distance classes ranging from 0 to over 100 m) did not significantly affect the nesting success or productivity of either species. Brown-headed Cowbirds ( Molothrus ater) parasitized 47% of all Wood Thrush nests and 10% of all Rose-breasted Grosbeak nests; parasitism significantly reduced Wood Thrush productivity but not that of Rose-breasted Grosbeaks. Our findings challenge the prevailing notion that small woodlots in a farmed landscape are invariably habitat sinks and offer additional incentive for habitat protection in settled landscapes where small forest fragments are often all that remain for conservation purposes. Resumen: Los bosques pequenos en paisajes agriculturales son generalmente vistos como sumideros poblacionales donde el exito de nidacion de aves canoras neotropicales migratorias es muy bajo como para sostener poblaciones. En 1996 y 1997 evaluamos el exito de nidacion y reproductivo del zorzalito maculado, Hylocichla mustelina y del picogrueso pechirrosado, Pheucticus ludovicianus en la region de Waterloo, un paisaje agricultural altamente fragmentado, con un 14% de la cobertura forestal en el Suroeste de Ontario. Localizamos 154 nidos de zorzales y 63 de picogrueso en 26 fragmentos pequenos de bosque (3–14 ha) y 15 fragmentos grandes (26–140 ha). Utilizamos el metodo Mayfield para determinar el exito de nidacion. A lo largo de todos los sitios el exito de nidacion fue de un 51% para los zorzales y de 46% para los picogruesos. El exito de nidacion y las tasas de productividad fueron usadas en un modelo de crecimiento poblacional simple que sugiere que los zorzales, pero no los picogruesos constituyeron una poblacion autosostenible. El tamano del bosque y las distancias de nidos al borde mas cercano del bosque (medidas en cinco categorias de distancia de 0 a> 100 m) no afectaron significativamente el exito de nidacion ni la productividad de las especies estudiadas. Los vaquero cabecicafe ( molothrus alter) parasitaron 47% del total de nidos de zorzales y 10% de los nidos del picogrueso; el parasitismo redujo significativamente la productividad del zorzalito pero no la del picogrueso. Nuestros resultados contrastan con la idea prevalente de que los lotes pequenos de bosques son habitats sumidero y ofrecen un incentivo adicional para la proteccion de habitats en paisajes habitados donde los fragmentos pequenos de bosque son todo lo que queda para propositos de conservacion.

Spin-polarised atomic hydrogen is used as a gaseous polarised proton target in high energy and nuclear physics experiments operating with internal beams in storage rings. When such beams are intense and bunched, this type of target can be depolarised by a resonant interaction with the transient magnetic field generated by the beam bunches. This effect has been studied with the HERA positron beam in the HERMES experiment at DESY. Resonances have been observed and a simple analytic model has been used to explain their shape and position. Operating conditions for the experiment have been found where there is no significant target depolarisation due to this effect., REVTEX, 6 pages, 5 figures

New ruthenium(II) bipyridyl polyaza receptors have been prepared and shown to bind and sense, via MLCT luminescent emission quenching, phosphate and ATP anions in aqueous solution.

A new family of aza-oxa open-chain and macrocyclic molecules functionalised with ferrocenyl groups have been synthesized and characterised. The crystal structures of the [HL1][PF6], [H2L3][PF6]2, [H2L4][PF6]2 and [H2L5][PF6]2 salts have been determined by single crystal X-ray procedures {L1 = 10-ferrocenylmethyl- 1,4,7-trioxa-10-azacyclododecane, L3 = 7,13-bis(ferrocenyl)-1,4,10-trioxa-7,13-diazacyclopentadecane, L4 = 1,8-bis[bis(ferrocenylmethylamino)]-3,6-dioxaoctane, L5 = 1,8-bis(ferrocenylmethylamino)-3,6-dioxaoctane}. They consist of cationic protonated amines linked via ionic interactions with hexafluorophosphate anions. Additionally hydrogen-bonding interactions have also been found. The receptors have been designed to promote discrimination, using electrochemical techniques, between toxic heavy metal ions such as Hg2+ over other commonly water present cations in aqueous environments. The presence in the receptors of oxygen and nitrogen donor atoms has been used to control the selectivity of large metal ions over small ones. Potentiometric and electrochemical studies have been mainly carried out to find pH ranges of selective electrochemical recognition. Potentiometric titrations were carried out in water (25°C, 0.1 mol dm-3 potassium perchlorate) for L1 and L2 [1,1′-(5,8-dioxa-2,11-diazadodecane-1,12-diyl)-ferrocene] and in 1,4-dioxane-water (25°C, 0.1 mol dm-3 potassium nitrate) for L3 and L5 with Ni2+, Cu2+, Zn2+, Cd2+, Pb2+ and Hg2+. All receptors show larger stability constants with Hg2+ than with the remaining metal ions studied. This is especially so for L1 and L2. The receptors L1, L2 and L5 are able electrochemically and selectively to sense the presence of Hg2+, whereas maximum electrochemical shifts are produced in L3 upon addition of Pb2+. Of importance is the large and selective electrochemical shift monitored in water for L2 and Hg2+ with an anodic displacement of the oxidation potential of ca. 130 mV which is one of the largest shifts ever reported in electrochemical cation sensing in water using related receptors. A good agreement has been found between potentiometric and electrochemical results. Selective electrochemical response against Hg2+ appears to be associated with (i) pH ranges of selective complexation or (ii) the existence of strong predominant receptor-metal complexes in a wide pH range. Additionally the electrochemical behaviour of receptors L1 and L2 in the presence of metal ions can be roughly predicted from potentiometric data. The stability constants of the complexes between L1 and Cu2+, Cd2+, Pb2+ and Hg2+ were also determined in the presence of Cl-. Whereas there is no important change in the stability constants of the L-H+-M2+ systems when M2+ = Cu2+, Cd2+ or Pb2+, there is a decrease of the co-ordination ability of L1 towards Hg2+. This is also reflected in electrochemical studies which demonstrate that [Hg(L1)]2+ electrochemically sense Cl- at pH 7. To the best of our knowledge this is the first time it has been shown that metal complexes functionalised with ferrocenyl groups can electrochemically sense anions.

The combustion/pyrolysis of three chemically different hydrocarbons, toluene, n-heptane, and propanol-1, has been investigated in reflected shock waves. The formation of soot and polycyclic aromatic hydrocarbons (PAHs) has been studied, and the factors which influence the production of these compounds during liquid spray combustion have also been investigated at temperatures between 1000 and 3000 K and pressures of 2–25 bar. The results indicate that formation of soot and PAH is significantly dependent on the chemical properties of fuel, temperature, and oxygen concentration, but the pressure dependence is found to be minimal in the pressure range less than 25 bar. The results are instrumental in adding to our understanding of the soot and PAH formation chemistry.

Non-aqueous routes to inorganic nanoparticles are supposedly based on the absence of water; here, this view is partially challenged, showing that the presence of water (or moisture) is probably necessary, and is surely useful to achieve a precise control over the growth/aggregation phenomena leading to titanium dioxide nanoparticles. This study is focused on the preparation of size-controlled and ligand-free titania (anatase) nanoparticles in water dispersion. This is achieved through a three-step process: 1) production of primary (3–4 nm) nanoparticles from titanium alkoxides (Ti(OnPr)4, Ti(OnBu)4 or Ti(OiPr)4) in benzyl alcohol through the controlled addition of water; 2) thermal growth phase, where the aggregation of primary nanoparticles at 80 °C leads to secondary nanoparticles with a typical fractal dimension of 2.2–2.4; the primary particles are still identifiable as the individual crystallites composing the secondary nanoparticles; 3) precipitation/re-dispersion in water, where secondary nanoparticles further agglomerate to yield tertiary nanoparticles. The size of the latter and their photocatalytic efficiency is primarily controlled by the nature of residual alkoxide chains; in particular, isopropoxide groups allow to produce anatase nanoparticles with an average size of 7–8 nm in water dispersion and in the absence of any stabilizing ligand, which is an unprecedented result.

The oxidation rates of soot particulates have been studied at high temperatures (1500–3500 K) in a shock tube in oxygen–argon mixtures at pressures between 4 and 14 atm. Complex Arrhenius plots were found above 2200 K for the lower oxygen concentrations with the rate going through a maximum and then increasing again. Below 2200 K, simple Arrhenius plots were obtained and the order of reaction with respect to oxygen was found to be 0.5.A final expression for the rate ω was obtained: log(ω/g cm–2 s–1)= log A+ 0.5 log([O2]/mol cm–3)– [graphic omitted]6366//T[graphic omitted] with log A= 3.731 ± 0.1, giving an activation energy of 121.9 ± 2.5 kJ mol–1 or log(ω/g cm–2 s–1)= log B+ 0.5 log([P(O2)]/atm)– [graphic omitted]6048//T[graphic omitted] with log B= 0.946 ± 0.1, giving an activation energy of 115.8 ± 2.8 kJ mol–1. From these data the reaction probabilities, α, for the attack of oxygen molecules on soot can be calculated to be α= 3.45 exp[graphic omitted]–14919//T[graphic omitted] which yields an activation energy of 124 037 J mol–1.No effect of total pressure other than that due to increasing oxygen was found. The results have been compared with those obtained by other workers.

Chitosan nanoparticles are popular carriers for the delivery of macromolecular payloads, e.g. nucleic acids. In this study, nanoparticles were prepared via complexation with triphosphate (TPP) anions and were successively coated with hyaluronic acid (HA). Key variables of the preparative process (e.g. chitosan and HA molecular weight) were optimised in view of the maximisation of loading with DNA, of the Zeta potential and of the dimensional stability, and the resulting particles showed excellent storage stability. We have focused on the influence of chitosan molecular weight on nanoparticle properties. Larger molecular weight increased their porosity (=decreased cross-link density), and this caused also larger dimensional changes in response to variations in osmotic pressure or upon drying. The dependency of nanoparticle porosity on chitosan molecular weight had a profound effect on the adsorption of HA on the nanoparticles; HA was apparently able to penetrate deeply into the more porous high molecular weight (684 kDa) chitosan nanoparticles, while it formed a corona around those composed of more densely cross-linked low molecular weight (25 kDa) chitosan. Atomic Force Microscopy (AFM) allowed not only to highlight the presence of this corona, but also to estimate its apparent thickness to about 20-30 nm (in a dry state). The different morphology has a significant effect on the way HA is presented to biomolecules, and this has specific relevance in relation to interactions with HA receptors (e.g. CD44) that influence kinetics and mechanism of nanoparticle uptake. Finally, it is worth to mention that chitosan molecular weight did not appear to greatly affect the efficiency of nanoparticle loading with DNA, but significantly influenced its chitosanase-triggered release, with high molecular chitosan nanoparticles seemingly more prone to degradation by this enzyme.

Undiscovered petroleum resources may be assessed using a computer program that simulates drilling each trap in a play and estimates the size of each potential discovery by multiplying together estimates of area of closure (Acles) and resources per unit area (VA). There are several ways of determining values forAcles andVA so that the method can be widely applied. As an example, the sales gas potential of part of the Cooper Basin in South Australia is assessed using statistical projections of loglinear models to determine values forAcles andVA. A discontinuity in these particular data appears to result from an improvement in the quality and density of the seismic surveying, demonstrating that an assessment based on widely spaced or poor-quality seismic surveys can underestimate sales gas potential.

This brief communication describes the observation of small amounts of C60 in soot formed in the liquid spray combustion of benzene behind reflected shock waves. As far as we are aware this is the first reported detection of C60 in shock waves at such high pressures and temperatures. The soot containing C60 was produced from combustion in argon containing 1% O2 at temperatures of about 2400K and pressures about 2.0 bar. Identification and separation of C60 from co-produced polycyclic aromatic hydrocarbons (PAHs) in the soot samples were made by H.P.L.C. and mass spectrometry.

The feasibility of synthesising disubstituted cyclopent-2-enones chemoselectively from unsymmetrical γ-diketones, using an aldol reaction directed by magnesium chelation, has been studied. Treatment of 3,3-dimethylhexane-2,5-dione 15 with aqueous sodium hydroxide (0.5 mol dm–3) gives a mixture of 3,5,5-trimethyl-12 and 3,4,4-trimethylcyclopent-2-enone 14 in an isomer ratio of 2.2 : 1. Insertion of an α-methoxycarbonyl grouping as a control element allows formation of a magnesium chelate 17 when treated with magnesium methoxide, and the major product is then mainly the undehydrated aldol 21. This, when treated with aqueous sodium hydroxide (0.5 mol dm–3) to dehydrate, hydrolyse and decarboxylate, gives the 3,5,5-trimethyl- and 3,4,4-trimethylcyclopent-2-enones in a nearly chemospecific ratio of 1 : 49. When 3-methoxycarbonyl-4,4-dimethylhexane-2,5-dione 16 is treated with aqueous sodium hydroxide (0.5 mol dm–3), omitting the magnesium methoxide treatment, the corresponding ratio of cyclopentenones was still an interesting 1 : 7.3. Treatment with sodium methoxide in methanol gives, by contrast, γ-lactone 27.Treatment of undecane-4,7-dione 34 with aqueous sodium hydroxide (0.5 mol dm–3) at reflux gives 2,3-dipropylcyclopent-2-enone 36 and 3-butyl-2-ethylcyclopent-2-enones 35 in a ratio of almost 1 : 1. Treatment of 6-methoxycarbonylundecane-4,7-dione 33 with magnesium methoxide in methanol gives undehydrated aldol which when treated with aqueous sodium hydroxide gives the dipropylcyclopent-2-enone 36 and 3-butyl-2-ethylcyclopent-2-enones 35 in 9 : 1 ratio. Conversely, the 5-methoxycarbonyldione 32 gives a corresponding ratio of 36 to 35 of 1 : 9. The best ratios attained, 1 : 15 for 36 and 35 from 32 and 20 : 1 for 36 and 35 from 33, were when magnesium methoxide in refluxing benzene or toluene were employed. There is still a strong chemoselective effect when the magnesium treatment is omitted.Preliminary examination of the corresponding cyclohex-2-enone systems gave poorer chemoselectivities when either procedure was employed. 6-Methoxycarbonyldodecane-5,9-dione 52 gave 2,3-dipropyl-54 and 3-butyl-2-ethyl-cyclohex-2-enone 55 in a ratio of ∼4 : 1 whilst the 5-methoxycarbonyldodecane-4,8-dione 53 gave a 1: ∼4 ratio.

AB Purpose: Hyperventilation increases the clearance of carbon monoxide (CO) from blood; thus, we hypothesized that CO elimination would be enhanced with exercise. Accordingly, this study examined the effect of exercise on the half-life of carboxyhemolobin elimination. Methods: Six healthy subjects (three males and three females) with mean +/- SD ages of 23 +/- 4 yr were exposed to CO sufficient to raise blood carboxyhemolobin concentration to 10-14% on five separate days. The half-life for CO elimination was measured breathing room air at rest and during exercise at three intensities. Results: Comparisons showed that the half-life decreased with exercise from that during rest in all subjects. The half-life was also measured during 100% oxygen breathing at the lowest exercise intensity of 63 +/- 15 W and found to be the least of all measured (23 +/- 4 min). Conclusions: 1) Exercise increased isocapnic ventilation, thereby decreasing the half-life of CO elimination. 2) The half-life of CO elimination represents a hyperbolic function of ventilation [y = y0 + (a / x)], and so increasing ventilation by exercise reaches a point of diminishing returns. 3) Breathing 100% oxygen during mild exercise is as effective in eliminating CO as treatment with hyperbaric oxygen. 4) Moderate exercise under room air conditions is as effective in eliminating CO as breathing oxygen at rest. Thus, the combination of mild exercise, hyperventilation, and normobaric hyperoxia (100% oxygen inhalation) may be considered the "triple therapy" for CO elimination in some patients. (C)2012The American College of Sports Medicine