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Introduction

There is strong evidence of the links between car-dependence and the physical inactivity pandemic. Physical inactivity accounts for 6–10% of major non-communicable diseases. Research consistently shows that unlike passive transport, active transport is associated with higher total daily physical activity (PA). While there are public policies that support PA in transport and, as a result, overall PA levels, the specific quantitative effect of such policies on PA behaviour has not been sufficiently investigated. The aim of this systematic review is to determine the level and type of evidence for policies in the area of transport that contribute to higher PA levels of the whole of society.

ABSTRACTIn vivoelectroporation (EP) has proven to significantly increase plasmid transfection efficiency and to augment immune responses after immunization with plasmids. In this study, we attempted to establish an immunization protocol using intradermal (i.d.) EP. BALB/c mice were immunized with a plasmid encoding HIV-1 p37Gag, either i.d. with the Derma Vax EP device, intramuscularly (i.m.) without EP, or with combinations of both. A novel FluoroSpot assay was used to evaluate the vaccine-specific cellular immune responses. The study showed that i.d. EP immunizations induced stronger immune responses than i.m. immunizations using a larger amount of DNA and that repeated i.d. EP immunizations induced stronger immune responses than i.m. priming followed by i.d. EP boosting. Two and three i.d. EP immunizations induced immune responses of similar magnitude, and a short interval between immunizations was superior to a longer interval in terms of the magnitude of cellular immune responses. The FluoroSpot assay allowed for the quantification of vaccine-specific cells secreting either gamma interferon (IFN-?), interleukin-2 (IL-2), or both, and the sensitivity of the assay was confirmed with IFN-? and IL-2 enzyme-linked immunosorbent spot (ELISpot) assays. The data obtained in this study can aid in the design of vaccine protocols using i.d. EP, and the results emphasize the advantages of the FluoroSpot assay over traditional ELISpot assay and intracellular staining for the detection and quantification of bifunctional vaccine-specific immune responses.

Assembly of active Fe-hydrogenase in the chloroplasts of the green alga Chlamydomonas reinhardtii requires auxiliary maturases, the S-adenosylmethionine-dependent enzymes HydG and HydE and the GTPase HydF. Genes encoding homologous maturases had been found in the genomes of all eubacteria that contain Fe-hydrogenase genes but not yet in any other eukaryote. By means of proteomic analysis, we identified a homologue of HydG in the hydrogenosomes, mitochondrion-related organelles that produce hydrogen under anaerobiosis by the activity of Fe-hydrogenase, in the pathogenic protist Trichomonas vaginalis. Genes encoding two other components of the Hyd system, HydE and HydF, were found in the T. vaginalis genome database. Overexpression of HydG, HydE, and HydF in trichomonads showed that all three proteins are specifically targeted to the hydrogenosomes, the site of Fe-hydrogenase maturation. The results of Neighbor-Net analyses of sequence similarities are consistent with a common eubacterial ancestor of HydG, HydE, and HydF in T. vaginalis and C. reinhardtii, supporting a monophyletic origin of Fe-hydrogenase maturases in the two eukaryotes. Although Fe-hydrogenases exist in only a few eukaryotes, related Narf proteins with different cellular functions are widely distributed. Thus, we propose that the acquisition of Fe-hydrogenases, together with Hyd maturases, occurred once in eukaryotic evolution, followed by the appearance of Narf through gene duplication of the Fe-hydrogenase gene and subsequent loss of the Hyd proteins in eukaryotes in which Fe-hydrogenase function was lost.

ABSTRACTAssembly of active Fe-hydrogenase in the chloroplasts of the green alga Chlamydomonas reinhardtiirequires auxiliary maturases, the S-adenosylmethionine-dependent enzymes HydG and HydE and the GTPase HydF. Genes encoding homologous maturases had been found in the genomes of all eubacteria that contain Fe-hydrogenase genes but not yet in any other eukaryote. By means of proteomic analysis, we identified a homologue of HydG in the hydrogenosomes, mitochondrion-related organelles that produce hydrogen under anaerobiosis by the activity of Fe-hydrogenase, in the pathogenic protist Trichomonas vaginalis. Genes encoding two other components of the Hyd system, HydE and HydF, were found in the T. vaginalisgenome database. Overexpression of HydG, HydE, and HydF in trichomonads showed that all three proteins are specifically targeted to the hydrogenosomes, the site of Fe-hydrogenase maturation. The results of Neighbor-Net analyses of sequence similarities are consistent with a common eubacterial ancestor of HydG, HydE, and HydF in T. vaginalisand C. reinhardtii, supporting a monophyletic origin of Fe-hydrogenase maturases in the two eukaryotes. Although Fe-hydrogenases exist in only a few eukaryotes, related Narf proteins with different cellular functions are widely distributed. Thus, we propose that the acquisition of Fe-hydrogenases, together with Hyd maturases, occurred once in eukaryotic evolution, followed by the appearance of Narf through gene duplication of the Fe-hydrogenase gene and subsequent loss of the Hyd proteins in eukaryotes in which Fe-hydrogenase function was lost.

This work describes a method to produce microstructured PDMS stamps that are metallized in two isolated sections, thus creating the possibility to electroprint a surface using such a stamp as both counter electrode and reference electrode in a surface contact electrochemical cell controlled using a potentiostat. This electromicrocontact printing method was used to perform patterned electroactivation of thiolated surfaces. Patterned electrooxidation of thiols to reactive thiolsulfinates/thiolsulfonates allowed for specific immobilization of thiolated polystyrene particles, showing the potential of this technique to be employed in selective covalent attachment of biomolecules through disulfide bonds.

Insect peptidoglycan recognition protein-S (PGRP-S), a member of a family of innate immunity pattern recognition molecules conserved from insects to mammals, recognizes bacterial cell wall peptidoglycan and activates 2 antimicrobial defense systems, prophenoloxidase cascade and antimicrobial peptides through Toll receptor. We show that mouse PGRP-S is present in neutrophil tertiary granules and that PGRP-S–deficient (PGRP-S-/-) mice have increased susceptibility to intraperitoneal infection with gram-positive bacteria of low pathogenicity but not with more pathogenic gram-positive or gram-negative bacteria. PGRP-S-/- mice have normal inflammatory responses and production of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6). Neutrophils from PGRP-S-/- mice have normal phagocytic uptake of bacteria but are defective in intracellular killing and digestion of relatively nonpathogenic gram-positive bacteria. Therefore, mammalian PGRP-S functions in intracellular killing of bacteria. Thus, only bacterial recognition by PGRP-S, but not its effector function, is conserved from insects to mammals.

Insect peptidoglycan recognition protein-S (PGRP-S), a member of a family of innate immunity pattern recognition molecules conserved from insects to mammals, recognizes bacterial cell wall peptidoglycan and activates 2 antimicrobial defense systems, prophenoloxidase cascade and antimicrobial peptides through Toll receptor. We show that mouse PGRP-S is present in neutrophil tertiary granules and that PGRP-S–deficient (PGRP-S-/-) mice have increased susceptibility to intraperitoneal infection with gram-positive bacteria of low pathogenicity but not with more pathogenic gram-positive or gram-negative bacteria. PGRP-S-/-mice have normal inflammatory responses and production of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6). Neutrophils from PGRP-S-/-mice have normal phagocytic uptake of bacteria but are defective in intracellular killing and digestion of relatively nonpathogenic gram-positive bacteria. Therefore, mammalian PGRP-S functions in intracellular killing of bacteria. Thus, only bacterial recognition by PGRP-S, but not its effector function, is conserved from insects to mammals.

This work describes a method for immobilization of biomolecules on surfaces via electrooxidation of surface thiols by generating thiolsulfinates/thiolsulfonates that display a high reactivity toward free thiols in molecules. This is done by applying a potential difference between a platinum cathode and a thiol-derivatized silicon surface as the anode, through a buffer solution. X-ray photoelectron spectroscopy data showed that the amount of thiolsulfinates/thiolsulfonates was voltage dependent. When a potential difference of 1.0 V was applied between the silicon surface and the platinum electrode for 1 min, about 80% of the thiols were converted to thiolsulfonates/thiolsulfinates. The results of comparative chronoamperometric experiments, using a three-electrode potentiostatic setup, indicate that the thiols are oxidized electrochemically at +0.6 V versus Ag/AgCl. This indicates the presence of a direct electrochemical oxidation of the thiols on the silicon surface rather than an oxidation of the thiols by, for example, oxygen formed during the oxidation of water. Peptides containing thiol groups were subsequently covalently bound to the surface through disulfide bonds involving 25% of the thiolsulfinates/thiolsulfonates, which indicates a fully saturated surface coverage with peptide molecules. It was possible to release 40% of the peptides using dithiothreitol. When a voltage was applied to such a surface for a second time, additional thiolsulfinates/thiolsulfonates were formed. This method, used together with nanosized electrodes or a scanning probe microscope tip as a counter electrode, will allow a spatially controlled immobilization of biomolecules on surfaces at the nanometer scale.

The electronic energy structure (EES) of Cu0.8Ni0.2Ti and Cu0.6Ni0.4Ti alloys, stoichiometric CuTi compound with a tetrahedral CuTi–type crystal lattice, and cubic NiTi was studied experimentally and theoretically. The experimental study of valence band EES was carried out by X‐ray photoelectron spectroscopy (XPS). The EES of both the stoichiometric compounds and the alloys was calculated using the cluster version of multiple scattering theory in a self‐consistent field approximation. The calculation and experimental results are in good agreement. The major contribution to XPS of the studied compounds is from the dstates of copper and nickel. The specifics of chemical bonding in the compounds are discussed. The EES of tetragonal Cu—Ni—Ti alloys is modeled.

The electronic energy structure (EES) of the valence band in tetragonal TiCu and Ti2Cu was studied experimentally and theoretically. The experimental study of valence band EES was carried out by X-ray photoelectron spectroscopy (XPS). The calculations were performed in terms of the cluster version of multiple scattering theory in a self-consistent field approximation. The results are compared with X-ray emission spectroscopy data available in the literature. The density of state curves agree well with spectroscopic data. The major contribution to XPS is from the copper d-states. The specifics of chemical bonding in the compounds leading to the observed changes in the shape of the valence band X-ray photoelectron spectra are discussed.

Oocytes from Xenopus laevishave provided a model system for studying the dynamic changes that occur in chromatin during gene activation. We have reconstituted glucocorticoid receptor (GR) induced transcription from the mouse mammary tumor virus (MMTV) promoter by intranuclear injection of an MMTV-driven reporter and cytoplasmic injection of synthetic mRNAGRinto Xenopusoocytes. Here we investigate the intranuclear distribution of injected DNA, which is assembled into chromatin. We show that this chromatin is organized as an intranuclear fibrous network. Unliganded GR is located in the cytosol and hormone triggers its nuclear translocation and association with the chromatin fibers. Furthermore, we analyze the intranuclear distribution of other factors involved in transcription from the MMTV promoter. Indirect immunofluorescence microscopy on cryostat-sectioned oocytes revealed that BRG1, which is a subunit of the SWI/SNF chromatin remodeling complex, as well as RNA polymerase II and recombinantly expressed Xenopusnuclear factor 1-B, are all associated with the endogenous chromosomes and the chromatin fibers formed on injected DNA. This association does not depend on specific DNA binding sites and appears to be nonspecific.

Peptidoglycan recognition protein (PGRP) is conserved from insects to mammals. In insects, PGRP recognizes bacterial cell wall peptidoglycan (PGN) and activates prophenoloxidase cascade, a part of the insect antimicrobial defense system. Because mammals do not have the prophenoloxidase cascade, its function in mammals is unknown. However, it was suggested that an identical protein (Tag7) was a tumor necrosis factor-like cytokine. Therefore, the aim of this study was to identify the function of PGRP in mammals. Mouse PGRP bound to PGN with fast kinetics and nanomolar affinity (Kd= 13 nm). The binding was specific for polymeric PGN or Gram-positive bacteria with unmodified PGN, and PGRP did not bind to other cell wall components or Gram-negative bacteria. PGRP mRNA and protein were expressed in neutrophils and bone marrow cells, but not in spleen cells, mononuclear cells, T or B lymphocytes, NK cells, thymocytes, monocytes, and macrophages. PGRP was not a PGN-lytic or a bacteriolytic enzyme, but it inhibited the growth of Gram-positive but not Gram-negative bacteria. PGRP inhibited phagocytosis of Gram-positive bacteria by macrophages, induction of oxidative burst by Gram-positive bacteria in neutrophils, and induction of cytokine production by PGN in macrophages. PGRP had no tumor necrosis factor-like cytotoxicity for mammalian cells, and it was not chemotactic on its own or in combination with PGN. Therefore, mammalian PGRP binds to PGN and Gram-positive bacteria with nanomolar affinity, is expressed in neutrophils, and inhibits growth of bacteria.

First results of an inter-laboratory comparison (27 participants in Europe, Japan and USA) of XPS data obtained with non-conducting samples are presented. Binding energies of Al 2s for alumina, N 1s and imide C 1s for Kapton and Sr 3p3/2 for a strontium titanate film on glass were obtained after static charge referencing with the help of 15 nm gold particles deposited at the surface of the test samples. For the alumina sample C 1s static charge referenced data are also presented. Repeat standard deviations (sr), between standard deviations (sb), reproducibility standard deviations (sR) and total means are evaluated from the experimental data. It can be stated that although the repeat standard deviation is as small as 0.05 eV in the best case, the standard deviation characterizing the reproducibility of the method is obviously not better than 0.15 eV in the best case at the present time. The knowledge of these standard deviations is important for metrology, validations of analytical procedures relying on qualitative photoelectron spectroscopy and XPS databanking. Copyright © 2000 John Wiley & Sons, Ltd.

First results of an inter‐laboratory comparison (27 participants in Europe, Japan and USA) of XPS data obtained with non‐conducting samples are presented. Binding energies of Al 2s for alumina, N 1s and imide C 1s for Kapton and Sr 3p3/2for a strontium titanate film on glass were obtained after static charge referencing with the help of 15 nm gold particles deposited at the surface of the test samples. For the alumina sample C 1s static charge referenced data are also presented. Repeat standard deviations (sr), between standard deviations (sb), reproducibility standard deviations (sR) and total means are evaluated from the experimental data. It can be stated that although the repeat standard deviation is as small as 0.05 eV in the best case, the standard deviation characterizing the reproducibility of the method is obviously not better than 0.15 eV in the best case at the present time. The knowledge of these standard deviations is important for metrology, validations of analytical procedures relying on qualitative photoelectron spectroscopy and XPS databanking. Copyright © 2000 John Wiley & Sons, Ltd.

The formation of self-assembled chemisorbed layers of cystamine, cysteamine, and 4-aminothiophenol on gold has been studied by XPS and voltammetry. These compounds, often used in the preparation of biosensors and modified electrodes, are shown to yield surface coverages of approximately 80% of that of a octadecanethiol monolayer within 5 min in millimolar aqueous and ethanolic solutions. The results of the XPS experiments reveal that a shoulder on the S 2p3/2 peak (situated at 162.1 eV) develops at 161.3 eV upon increasing the adsorption time from minutes to 1 week and that the initial rate of formation of the shoulder is higher for cystamine than for cysteamine. This shoulder is believed to be due to the presence of a sulfur species with a higher coordination number with respect to gold. Increased adsorption times also give rise to increased amounts of oxidized carbon and sulfur in the films. The oxidation of the sulfur in the thiols results in a detachment of the molecules from the gold surface, as indicated by XPS experiments with different takeoff angles. The main N 1s peak for cystamine is shifted toward higher binding energies for increasing adsorption times while two prominent nitrogen peaks are generally seen for cysteamine. For cysteamine, increasing adsorption times result in an increase of the main nitrogen component at the higher binding energy, yielding an apparent shift in the nitrogen peak with time similar to that seen for cystamine. Possible explanations for these experimental findings are discussed. Cystamine, cysteamine, and 4-aminothiophenol films on gold are shown to be irreversibly oxidized in the gold oxide formation region. On the basis of evaluation of the oxidation charge, surface coverages of approximately 1 × 10^-9 mol/cm² were obtained for adsorption times between 5 min and 1 week.

Various applications of a new geophysical reconstruction method, generalized acoustical diffraction tomography (GADT), which is based on transmission data as input are considered. Conventional diffraction tomography methods normally require linearization with respect to a uniform reference medium and regular sampling along a straight line. Thus, these methods will not work well when the background is strongly non‐uniform and/or the acquisition geometry is arbitrary. However, GADT can, in principle, handle both irregularly spaced data, curved acquisition lines, and non‐uniform background models. A number of controlled model tank and field experiments, where the model and the test object(s) are known a priori, have been carried out. After acquiring the tomographic data in each experiment, these are used to compute a reconstruction of the model, which can then be compared with the actual, known model. The method's ability to yield high‐quality images of the different targets is demonstrated.

A generalized diffraction tomography algorithm is developed, which in principle can handle irregularly spaced data, curved acquisition lines and non‐uniform background models. By direct comparison with medical diffraction tomography, it is shown that the generalized method involves the same two processing steps: data filtering and back‐propagation. The filter handles the irregular sampling of the model space and the uneven energy coverage, while the back‐propagation operator removes the wave propagation effects. Paraxial ray‐tracing techniques are employed to compute both these quantities. In medical diffraction tomography, the resolution vector (i.e. the Fourier vector of the model space) is defined by the incident and scattered plane‐wave directions. It is shown here that a similar relationship exists for a non‐uniform background, where the resolution vector at a particular image point is defined by the incident and scattered ray directions. Consequently, the impulse response of the generalized algorithm becomes space variant. Finally, a general processing procedure for transmission mode seismic data, based on this generalized algorithm, is proposed. The potential of the method is demonstrated using synthetic cross‐hole data.

The shake-up structure of the carbon 1s electron line in the spectrum of benzene has been studied by ESCA in high resolution and also theoretically, by means of the Pariser—Parr—Pople (PPP) method, including configuration interaction (CI). The calculated positions of the different shake-up lines relative to the main peak are found to be in surprisingly good agreement with experiment, the errors in excitation energies being a few per cent in all cases. On the basis of the calculations all observed lines in the spectrum can be assigned to excitations in the π system of the ionized molecule.

In this paper, quantitative tomographic reconstructions of biological tissue are presented. First, the experimental setup and a hybrid filtered backpropagation (FBP) technique are briefly described. Using this technique, which includes exact backpropagation of data prior to reconstruction by means of the classical FBP algorithm, quantitative velocity maps of relatively large biological objects can be obtained. Since the FBP algorithm is based on a first-order scattering approximation, the deteriorating effects of higher-order scattering in diffraction tomography are also discussed. The higher-order scattering limits the size of the biological object to a few centimeters.

Tricyclohexylphosphine (TCHP) adsorbates on rhodium, prepared both from solution and by sublimation in UHV are studied by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), and temperature-programmed desorption (TPD). XPS and IRAS are used to investigate the molecular orientation of the adsorbates and the coordination to the surface. TPD is used to study the stability of the adsorbates. Molecular surface interactions causing chemical shifts in the core level spectra of the adsorbates on rhodium are investigated using multilayer films and adsorbates on gold as references. In the solution deposition procedure, freshly evaporated rhodium samples are shortly exposed to air, resulting in oxygen covered surfaces. The P(2p) core level XPS spectrum shows only one type of phosphorus with a P(2p3/2) binding energy about 2.7 eV higher than when adsorbed on gold. This is in agreement with molecular adsorption through oxygen to the surface. To study the interaction of TCHP with clean rhodium we also prepared a TCHP adsorbate by an in situ sublimation process in UHV. One dominating state of phosphorus is observed with a P(2p3/2)binding energy about 2.6 eV lower than when adsorbed from solution, but close to what was found when adsorbed on gold. This indicates formation of a soft donor/acceptor bond due to a direct coordination of the molecule through the phosphorus lone pair orbital to the rhodium surface. The soft donor/acceptor and oxygen bridging to rhodium lead to a large electronic reorganization of the phosphorus atom, which manifests itself as substantial infrared peak shifts of the cyclohexyl modes, especially the CH2 stretches. Combined IRAS and TPD measurements show molecular desorption at 465 K for the UHV prepared monolayer, which is consistent with strong chemisorption to the rhodium surface.

Mixed self-assembled monolayers provide an attractive model system for investigating the role of different molecules in biological membranes. This paper describes the preparation and characterization of a novel type of mixed monolayer assemblies composed of thiol analogues of cholesterol and fatty acid. The mixed monolayers are prepared by coadsorbing 11-mercaptoundecanoic acid (MUA) and thiocholesterol (cholest-5-ene-3β-thiol, TC) from solution directly onto evaporated gold surfaces. The influence of TC on the molecular composition and conformation in the mixed monolayer is analyzed by using a combination of infrared reflection−absorption spectroscopy (IRAS), X-ray photoelectron spectroscopy (XPS), ellipsometry, contact angle measurement, and cyclic voltammetry. The results indicate that the TC molecules maintain their conformation in the mixed monolayers, whereas the MUA molecules display a significantly more disordered conformation as compared to the MUA molecules in the pure monolayer. Cyclic voltammetry shows that the mixed monolayers are more densely packed and less permeable than the pure TC and MUA monolayers. The kinetics of the coadsorption of TC and MUA from ethanol indicates that adsorption of TC initially is strongly preferred over MUA but that MUA dominates over TC at long coadsorption times. This is because there is a larger energy gain per unit area in forming monolayers with MUA. Further, it is also seen that the number of molecules per unit area changes with the molecular composition, as a consequence of the different sizes of TC and MUA. We present herein a method for calculating the mole fraction of TC on the gold surface, χTC, which accounts for this variation. As a consequence of the dissimilar size and shape of the two molecules, the wetting properties of the mixed monolayer are found to be mainly governed by the fractional area of TC, rather than by the molecular composition of TC, χTC.

α-Functionalized terthiophenes containing disulfide (−S−T3−H)2 and alkanethiol (HS−(CH2)11−T3−H) anchoring groups have been synthesized for direct immobilization onto gold. Monolayer structures of these compounds are prepared by spontaneous assembly from ethanol solutions on evaporated gold substrates and thoroughly characterized by ellipsometry, contact angle goniometry, infrared and X-ray photoelectron spectroscopy, and cyclic voltammetry. The two molecules coordinate to the gold substrate exclusively via the anchoring groups upon formation of gold−thiolate bonds. The kinetics of monolayer formation vary dramatically for the two compounds. The alkanethiol analogue assembles rapidly, within a few minutes, and forms a densely packed and highly organized monolayer, with the alkyl chains in an almost perfect all-trans conformation and the Cα−Cα axis of the α-T3 units tilted about 14° away from the surface normal. The assembly process is much slower for the disulfide, but an organized monolayer with an average α-T3 chain tilt of about 33° will eventually form when the assembly is allowed to equilibrate with a solution containing the disulfide for at least 1 day. Moreover, the two monolayer assemblies also display a remarkably different electrochemical behavior. The heterogeneous electron-transfer rate at the disulfide-covered gold substrate is almost indistinguishable from that at bare gold, suggesting that the assembly contains a large number of easily accessible defects. An alternative mechanism for explaining the large electron-transfer rate involving electronic coupling via the conjugated π-system of the α-T3 units is also proposed. The electrochemical response is significantly reduced for the HS−(CH2)11−T3−H assembly, but another type of defects, the so-called “shallow defects” originating from sparsely populated areas on the electrode surface, can be identified.

In this paper, quantitative tomographic reconstructions of biological tissue are presented. First, the experimental setup and a hybrid filtered backpropagation (FBP) technique are briefly described. Using this technique, which includes exact backpropagation of data prior to reconstruction by means of the classical FBP algorithm, quantitative velocity maps of relatively large biological objects can be obtained. Since the FBP algorithm is based on a first-order scattering approximation, the deteriorating effects of higher-order scattering in diffraction tomography are also discussed. The higher-order scattering limits the size of the biological object to a few centimeters.

Calibration of the binding energy scale in x‐ray photoelectron spectroscopy (XPS) requires location of the zero point. This zero point has previously been identified with the inflection point in the Fermi‐edge region of a valence‐band photoemission spectrum of nickel. Comparison of photoemission spectra of nickel and silver measured with monochromated x‐rays shows that the inflection points near the Fermi edge differ by 45±5 meV (where the stated uncertainty indicates the standard uncertainty) at an instrumental energy resolution of 0.30 eV. This difference is due to differences in the valence‐band densities of states (DOS) of the two metals. Simulations of the Ni photoemission spectrum have been performed based on the DOS calculated by Eckhardt and Fritsche, and the simulated spectrum agrees well with the measured spectrum in the near‐edge region. Additional simulations of the Ni photoemission spectrum have been carried out with both monochromated Al x‐rays and unmonochromated Mg and Al characteristic x‐rays to determine how the Ni near‐edge inflection point varies with the energy resolution of the electron energy analyzer in XPS. © 1998 John Wiley & Sons, Ltd.

A mathematical model for the liver uptake and excretion of 99mTc-diethyl IDA has been formulated and data from four patient studies have been fitted to the model, resulting in values for the model parameters. The model includes compartments for blood, extravascular space, hepatocytes, bile ducts, and kidneys. The parameter values obtained reflect a rapid exchange between blood and extravascular space and a significant reverse flow of the radiopharmaceutical from the liver to the blood.

Calibration of the binding energy scale in x-ray photoelectron spectroscopy (XPS) requires location of the zero point. This zero point has previously been identified with the inflection point in the Fermi-edge region of a valence-band photoemission spectrum of nickel. Comparison of photoemission spectra of nickel and silver measured with monochromated x-rays shows that the inflection points near the Fermi edge differ by 45±5 meV (where the stated uncertainty indicates the standard uncertainty) at an instrumental energy resolution of 0.30 eV. This difference is due to differences in the valence-band densities of states (DOS) of the two metals. Simulations of the Ni photoemission spectrum have been performed based on the DOS calculated by Eckhardt and Fritsche, and the simulated spectrum agrees well with the measured spectrum in the near-edge region. Additional simulations of the Ni photoemission spectrum have been carried out with both monochromated Al x-rays and unmonochromated Mg and Al characteristic x-rays to determine how the Ni near-edge inflection point varies with the energy resolution of the electron energy analyzer in XPS. © 1998 John Wiley & Sons, Ltd.

Molecular gradients of ω-substituted alkanethiols HS(CH2)15X (X:CH3, CH2OH, CO2CH3, CH2C&tbd1;N) were prepared on sputtered gold films by using a novel cross-diffusion methodology. Ellipsometry, contact angle measurements, infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used to monitor the coverage, chain conformation and gradient profiles. The XPS analysis were performed with improved lateral resolution as compared to our earlier infrared study (Langmuir 1995, 11, 3821) by imaging a 160 μm wide segment of the gradient surface on the slit of the XPS analyzer and by using a step size of 0.5 mm. The so-obtained gradient profiles are expected to be more representative of the true composition profiles and were for the three gradients investigated found to be 5−6 mm, about 2−3 mm shorter than the corresponding profiles obtained by scanning infrared spectroscopy. The coverages (alkyl chain densities) were found to be constant for the gradients prepared from thiols with relatively small tail groups OH, C&tbd1;N and CH3, whereas a minor reduction in coverage, ≈ 3−4%, was observed in a narrow range for the gradient containing the CO2CH3-terminated alkanethiol. This change is, however, too small to be detected by ellipsometry and infrared spectroscopy and supports a model where the gradient assemblies approach the limiting structure of densely packed all trans polymethylenes.

The adsorption of 3-(2-thioethyl)pyrrole (3-TEP) and 1-(2-thioethyl)pyrrole (1-TEP) on gold has been studied in ultrahigh vacuum with infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption mass spectroscopy. Depositions were made from liquid phase at atmospheric pressure, from gas phase in ultrahigh vacuum, and from gas phase at atmospheric pressure. Both molecules were found to chemisorb to the gold surface regardless of the deposition method. Most of the 3-TEP, however, broke up, losing the pyrrole ring as it adsorbed on the surface. Both monolayers were sensitive to oxygen and oxidized quickly if stored in air. Deposition of 1-TEP from solution or vapor in air gave a higher desorption peak temperature than deposition from gas phase in UHV. The masses of the desorbing fragments that were detected from the heated monolayers were smaller than those seen upon introducing 1-TEP gas into the UHV system, revealing that a partial decomposition of the adsorbed molecules occurred prior to or at desorption. Some samples were electrochemically cycled to positive potentials to investigate the stability of the monolayers. A large fraction of the 1-TEP and 3-TEP stayed on the surface when cycled to 0.8 V, but some oxidation, fragmentation, and desorption were seen at higher potentials.

Results from an MO-SCF-LCAO study of the electronic structure of the sulphate ion is reported. An extended sp basis set of contracted Gaussian functions has been used together with 3d polarization functions on the sulphur atom. The effect of these functions has been found to be significant, but not as large as has been suggested from previous calculations made with a minimal sp-basis. The effect of the 3d functions on a number of expectation values of one-electron operators has been studied.

Results from anab initio MO-SCF-LCAO study of the thiophene molecule, using an extended set of contracted Gaussian basis functions, are presented. The ordering of the molecular orbitals and the ionization energies are discussed in relation to experimental data from electron spectroscopy. A number of molecular properties have been computed in good agreement with available experimental information. The effect of 3d functions on sulphur for the description of the chemical bond and for the physical and chemical properties of thiophene is elucidated. Molecular potential energy maps are used in a discussion of the mechanism for electrophilic substitution reactions.

•Policies that support physical activity (PA) in the school-setting have promise but their impact is poorly understood.•Nine policy action areas for which there was evidence of impact were identified. These were whole-school PA policy, physical education, sport/extracurricular PA, classroom-based PA, active breaks, physical environment, shared use agreements, active school transport and surveillance.•Evidence supports the effectiveness of PA policy actions within the school-setting but cautions a “one-size fits all” approach.•Further evaluation of policy implementation to maximise translation into practice is required.•Greater clarity regarding terminology, measurement, and methods for evaluation of policy interventions is needed, and suggestions pro vided.

This work describes an efficient novel method to incorporate reactive disulfide bonds onto a silica surface under mild reaction conditions. The reactive thiol groups introduced onto the silicon surface in the first reaction step will be oxidized but easily converted into highly reactive thiopyridyl groups, which can therefore easily be utilized for further organic synthesis involving thiol-containing molecules. This is done in a way that yields approximately a monolayer of reactant on the surface, thereby not adding to the roughness of the surface, of special importance, for instance, for single molecule interaction studies.

The blue Danzig woad ash was reproduced in an historical chemical experiment . As its colouring agent alkali hypomanganate could be identified. The portion of hvpomanganate formed depends on the alkali contents of the product, the heating time, and, especially, the heating temperature

Background: The field of physical activity abounds with recommendations, guidelines, action plans and other documents published by experts, organizations and institutions at the national and international level. However, working with these documents is difficult since similar names (e.g. “recommendations”) may be used to label substantially different contents, while identical topics may hide behind different monikers (e.g. “guidelines” and “strategy”). Methods: We built on an existing framework conceptualizing categories of physical activity evidence and on the Doern continuum for policy instruments to develop a nine-field matrix that classifies physical activity-related publications based on their evidence type and degree of coercion. We used a selection of eleven physical activity documents to perform an exploratory test of the functions and utility of the typology. Results: Placing central physical activity documents into the typology shows that recommendations, guidelines, and policies are found across the entire matrix, regardless of their denomination. It also suggests that some documents transcend boundaries between types by falling into more than one category, and that some categories may be underrepresented in current physical activity promotion. Conclusions: A typology to classify physical activity guidelines, recommendations, and policies can help us acquire a better overview of the landscape of existing physical activity documents than simple distinctions based on document names. It may guide both current initiatives and future development work in the field. It could also serve as a point of departure for future research, as conducting systematic overviews of the literature based on this typology may help reveal important gaps in current physical activity promotion.